123 results on '"F., Hansen"'
Search Results
2. Computational fluid dynamics (CFD) modeling applied to biological wastewater treatment systems: An overview of strategies for the kinetics integration
- Author
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M.C. Sadino-Riquelme, A. Donoso-Bravo, F. Zorrilla, E. Valdebenito-Rolack, D. Gómez, and F. Hansen
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General Chemical Engineering ,Environmental Chemistry ,General Chemistry ,Industrial and Manufacturing Engineering - Published
- 2023
3. Predicting Hearing Loss in Testicular Cancer Patients after Cisplatin-Based Chemotherapy
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Sara Garcia, Jakob Lauritsen, Bernadette K. Christiansen, Ida F. Hansen, Mikkel Bandak, Marlene D. Dalgaard, Gedske Daugaard, and Ramneek Gupta
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History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2022
4. Childhood cancer confers increased risk of migraine – A Danish nationwide register study
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Olafur B. Davidsson, Klaus Rostgaard, Lisa Lyngsie Hjalgrim, Mona A. Chalmer, Isa A. Olofsson, Signe Holst Søegaard, Jeanette F. Winther, Line Kenborg, Thomas F. Hansen, and Henrik Hjalgrim
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Pediatric cancers/childhood cancers ,Cancer Research ,Oncology ,Epidemiology ,Survivorship research ,Migraine - Abstract
Background: Investigations of migraine among childhood cancer survivors have predominantly relied on self-reported information and hospital discharge diagnoses. Alone, both approaches are liable to bias. We used Danish nationwide registers to obtain data on both prescriptions of acute migraine medications (antimigraines) and hospital discharge diagnoses of migraine to assess the relative risk of migraine across a wider spectrum of migraine presentations than previously studied. Methods: We followed a Danish population-based cohort of 7771 individuals with childhood cancer diagnosed in the period from Jan 1st, 1978 to Dec 31st, 2017, for risk of prescription antimigraine initiation and for risk of hospitalization due to migraine. Rates of hospitalization were assessed for the entire follow-up period whereas rates of antimigraine initiations were assessed in the period from Jan 1st, 1997, to Dec 31st, 2017. Relative to the general population without childhood cancer, standardized incidence ratios (SIRs) were calculated for each outcome. Results: Individuals exposed to childhood cancer were at increased risk of antimigraine initiation (SIR of 1.24, 95% CI: 1.11–1.38) and of migraine hospitalization (SIR of 2.44, 95% CI: 1.87–3.12) from the day of their cancer diagnosis and up to 40 years after. Conclusions: Individuals diagnosed with childhood cancer have a higher risk of migraine of varying presentations, in addition to migraine resulting in hospitalization as previously reported. This potentially preventable problem warrants clinical attention.
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- 2022
5. Effects of dietary protein level and energy intake from 50 to 120 kg on body weight, back fat thickness and body composition in gilts
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J. Hales, A. V. Strathe, Pia Brandt, Charlotte Amdi, C. F. Hansen, and T. S. Bruun
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Dietary protein ,Low energy ,Animal science ,General Veterinary ,Back fat ,Body fatness ,Animal Science and Zoology ,Composition (visual arts) ,Factorial experiment ,Biology ,Body weight - Abstract
Body composition and body weight at mating plays an important role in reproductive performance and longevity of the sows, and therefore the dietary supply of protein and energy during rearing of the gilts are manipulated to obtain a more optimal body weight and composition at mating. The objective of the present study was to design a smaller but fatter gilt through different levels of dietary protein and different feeding strategies. It was hypothesized that gilts fed a low dietary protein concentration and had a high energy intake would have a lower BW and higher body fatness compared with gilts fed higher dietary protein levels with low energy intake. A total of 44 gilts entered the experiment at a BW of 47.6 ± 2.6 kg and were randomly allotted to one of six treatments in a 3 × 2 factorial experiment. The six dietary treatments consisted of three dietary protein levels (low (LP), medium (MP), high (HP)) and two energy levels (high (HE) and low (LE)). The BW of the gilts was recorded weekly for 84 days and back fat (BF) thickness was measured at day 1, 42 and 84. The body composition of the gilts was measured at day 1 and 84 by dual-energy x-ray absorptiometry (DXA) scans. At day 84 gilts fed HP and HE had the greatest BW (136 kg) and gilts fed LP and MP at LE had the least BW (107–109 kg; P P P
- Published
- 2019
6. High-yielding lactating sows maintained a high litter growth when fed reduced crude protein, crystalline amino acid-supplemented diets
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C. F. Hansen, A. V. Strathe, Jens-Erik Zerrahn, Camilla K Hojgaard, and T. S. Bruun
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0301 basic medicine ,Litter (animal) ,Body weight ,High yielding ,03 medical and health sciences ,chemistry.chemical_compound ,Animal science ,Crude protein ,Weaning ,High-yielding ,Lactose ,chemistry.chemical_classification ,General Veterinary ,Milk protein ,Back fat ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,Amino acid ,Milk ,030104 developmental biology ,chemistry ,Sow ,piglet ,Animal Science and Zoology ,amino acid - Abstract
The study was conducted to determine the optimal standardized ileal digestible (SID) CP level to maximize litter gain in high-yielding lactating sows when feeding reduced CP, crystalline amino acid-supplemented diets. In total, 520 Landrace × Yorkshire sows (parity 1 to 5) were allocated to 1 of 6 diets from day 2 post-partum when litters were standardized to 14 piglets. All diets were formulated to meet or slightly exceed Danish recommendations for Lys, Met, Met + Cys, Thr and Trp using crystalline amino acids. Diets contained 116, 126, 132, 138, 144, and 153 g SID CP per kg (as-fed). Sow body weight, back fat thickness, and litter weight were recorded at litter standardization and at weaning. On a subsample of 72 sows (parity 2 to 4), milk samples were collected at day 3, 10 and 17 post-partum, and blood was sampled at day 10 and 17 post-partum. All data were subjected to ANOVA using the MIXED procedure in SAS. Litter size at weaning was not affected by the dietary CP content (13.0 ± 0.06; P = 0.40), nor was litter ADG (3.13 ± 0.03 kg/d; P = 0.52), nor milk contents of fat and lactose (P > 0.05). Likewise, the daily changes in sow body weight (−0.58 ± 0.04 kg/d, P = 0.44) and back fat thickness (−0.15 ± 0.004 mm/d, P = 0.20) were similar across dietary treatments. Milk protein (P 0.05), but concentrations of plasma urea nitrogen were elevated (P
- Published
- 2019
7. Phenology, cold injury and growth of American chestnut in a Range-Wide provenance test
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Paul G. Schaberg, Paula F. Murakami, Kendra M. Collins, Christopher F. Hansen, and Gary J. Hawley
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Forestry ,Management, Monitoring, Policy and Law ,Nature and Landscape Conservation - Published
- 2022
8. First description of Onchocerca flexuosa infections in Danish red deer (Cervus elaphus)
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Stine T, Nielsen, Mette F, Hansen, Mariann, Chriél, and Heidi H, Petersen
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Male ,General Veterinary ,Deer ,Denmark ,Animals ,Female ,Parasitology ,Onchocerca - Abstract
The prevalence of Onchocerca infection in wild cervids from Denmark was studied in 119 fallow deer (Dama dama), 123 red deer (Cervus elaphus), 51 roe deer (Capreolus capreolus) and eight sika deer (Cervus Nippon) shot during the hunting season from October 2017 to January 2018 from 18 geographical locations across Denmark. The carcasses were macroscopic checked for nodules, and skin samples were examined for microfilaria. All roe deer, fallow deer and sika deer were negative for Onchocerca, while 30.9% red deer were positive for either microfilaria, nodules or both. Significantly more adult red deer (50.8%; 37.6-62.4; p 0.0001) were infected with Onchocerca than juveniles1 year (7.8%; 2.1-18.5), while there was an insignificant (p = 0.075) difference in prevalence observed between males (17.4%; 7.8-31.4) and females (41.7%; 30.2-53.9). Onchocerca-positive red deer were observed from 91.7% (11/12) of the sampled geographical locations. Species identification was done on adult worms from nodules taken from the lumbar region of 20 red deer of different geographical origin by sequencing the mitochondrial 12S, 16S and nad5 gene fragments. The sequences matched with previously published sequences for Onchocerca flexuosa. The high prevalence of Onchocerca infection caused by O. flexuosa in red deer in Denmark shows that Denmark has favourable vector conditions and a suitable environment for the maintenance of the parasite. To our knowledge, this is the first systematic study of Onchocerca in wild-living cervids in Denmark.
- Published
- 2022
9. Early intervention with enrichment can prevent tail biting outbreaks in weaner pigs
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Björn Forkman, R. B. D'Eath, H. P. Lahrmann, M. E. Busch, Jens Nielsen, and C. F. Hansen
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Litter (animal) ,Tail-biting ,genetic structures ,General Veterinary ,040301 veterinary sciences ,Production cost ,0402 animal and dairy science ,Outbreak ,04 agricultural and veterinary sciences ,Biology ,Straw ,040201 dairy & animal science ,0403 veterinary science ,Animal science ,Pig farming ,Animal Science and Zoology ,Weaner pigs ,Cage - Abstract
Tail biting is a serious animal welfare problem in the modern pig production. A frequently studied preventive measure is enrichment materials, and increasing levels of enrichment materials, especially litter materials, reduces the risk of tail biting. However, permanent access to litter materials, can cause blockage of the slurry system and increase production cost. The aim of the present study was, therefore, to investigate if providing extra enrichment material, when observing the first tail damage could reduce the prevalence of tail biting outbreaks. The study included 1804 weaner pigs from 7 to 30 kg distributed in 60 pens with intact tails. As basic enrichment material, pens were equipped with two wooden sticks and daily provided with approximately 400 g of fine chopped straw. From outside the pen pigs were checked for tail damages three times weekly. When the first tail damage (fresh or scabbed) was recorded, the pen was assigned to one of four treatments; chopped straw (approximately 200 g/pen) on the floor (straw), haylage in a spherical cage (haylage), hanging rope with a sweet block (rope) or no extra material (control). From first treatment day and until a tail biting outbreak, tails were scored three times weekly. A tail biting outbreak occurred when four pigs in a pen had a tail damage, irrespective of wound freshness. The experiment was designed to compare the prevalence of tail biting outbreaks in each of the extra material group with the control group. A treatment was carried out in 44 of the 60 pens: 10 pens with straw, 8 pens with haylage, 7 pens with rope and 19 control pens. The risk of a tail biting outbreak was significantly lower in pens with haylage and straw compared with control pens (P
- Published
- 2018
10. Tail posture predicts tail biting outbreaks at pen level in weaner pigs
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C. F. Hansen, H. P. Lahrmann, M. E. Busch, Björn Forkman, and R. B. D'Eath
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Tail-biting ,genetic structures ,040301 veterinary sciences ,0402 animal and dairy science ,Direct observation ,Outbreak ,04 agricultural and veterinary sciences ,Biology ,040201 dairy & animal science ,0403 veterinary science ,Animal science ,Food Animals ,Weaning ,Animal Science and Zoology ,Scan sampling ,Weaner pigs - Abstract
Detecting a tail biting outbreak early is essential to reduce the risk of pigs getting severe tail damage. A few previous studies suggest that tail posture and behavioural differences can predict an upcoming outbreak. The aim of the present study was therefore to investigate if differences in tail posture and behaviour could be detected at pen level between upcoming tail biting pens (T-pens) and control pens (C-pens). The study included 2301 undocked weaner pigs in 74 pens (mean 31.1 pigs/pen; SD 1.5). Tails were scored three times weekly (wound freshness, wound severity and tail length) between 07:00 h–14:00 h from weaning until a tail biting outbreak. An outbreak (day 0) occurred when at least four pigs had a tail damage, regardless of wound freshness. On average 7.6 (SD 4.3) pigs had a damaged tail (scratches + wound) in T-pens on day 0. Tail posture and behaviour (activity, eating, explorative, pen mate and tail directed behaviour) were recorded in T-pens and in matched C-pens using scan sampling every half hour between 0800–1100 h 1700–2000 h on day -3, -2 and -1 prior to the tail biting outbreak in T-pens. Further, to investigate if changes in tail posture could be a measure for use under commercial conditions, tail posture was recorded by direct observation from outside the pen. The live observations were carried out just before tail scoring on each observation day until the outbreak. The video results showed more hanging/tucked tails in T-pens than in C-pens on each recording day (P 8 tail damaged pigs than in pens with 4–5 tail damaged pigs (P
- Published
- 2018
11. Reinforcement learning based process optimization and strategy development in conventional tunneling
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Zhongqiang Liu, Georg Hermann Erharter, Tom F. Hansen, and Thomas Marcher
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business.industry ,Computer science ,Process (engineering) ,0211 other engineering and technologies ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,computer.software_genre ,0201 civil engineering ,Strategy development ,Control and Systems Engineering ,Virtual machine ,021105 building & construction ,Reinforcement learning ,Process optimization ,Artificial intelligence ,business ,computer ,Quantum tunnelling ,Civil and Structural Engineering - Abstract
Reinforcement learning (RL) - a branch of machine learning - refers to the process of an agent learning to achieve a certain goal by interaction with its environment. The process of conventional tunneling shows many similarities, where a geotechnician (agent) tries to achieve a breakthrough (goal) by excavating the rockmass (environment) in an optimum way. In this paper we present a novel RL based framework for strategy development for conventional tunneling. We developed a virtual environment with the goal of a tunnel breakthrough and with a deep Q-network as the agent's architecture. It can choose from different excavation sequences to reach that goal and learns to do so in an economical and safe way by getting feedback from a specially designed reward system. Result analyses show that the optimal policies have great similarities to current practices of sequential tunneling and the framework has the potential to discover new tunneling strategies.
- Published
- 2021
12. Increased dietary protein levels during lactation improved sow and litter performance
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C. F. Hansen, Niels Geertsen, A. V. Strathe, T. S. Bruun, and Jens Erik Zerrahn
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0301 basic medicine ,Litter (animal) ,medicine.medical_specialty ,Back fat ,Chemistry ,media_common.quotation_subject ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,03 medical and health sciences ,chemistry.chemical_compound ,030104 developmental biology ,Endocrinology ,Dietary protein ,medicine.anatomical_structure ,Animal science ,Internal medicine ,Lactation ,Linear regression ,medicine ,Weaning ,Animal Science and Zoology ,Reproduction ,Lactose ,media_common - Abstract
The study was conducted to investigate the effect of increasing balanced dietary protein for hyper-prolific lactating sows. In total 544 sows (parity 1–4) was allotted to one of six diets from day 2 post-partum until weaning. The diets were analyzed to have a standardized ileal digestible (SID) crude protein (CP) level of 104.3, 113.3, 120.9, 128.5, 139.2 or 150.0 g/kg. At d 2 post-partum litters were standardized to 14 piglets and body weight (BW), back fat (BF) thickness of sows and litter weight were recorded. Body weight, BF thickness and litter weight was also recorded at weaning. On a subsample of 70 sows (parity 2 and 3) milk samples were obtained at day 3, 10 and 17 post-partum and analyzed for fat, CP and lactose. In the analysis of the dose-response data the dietary SID CP concentration were used as explanatory variable. The abovementioned response variables were fitted with linear broken-line, quadratic broken-line and linear regression models. Sow BW and BF loss reached a break point at 143 g SID CP/kg and 127 g SID CP/kg, where sows lost 0.58 kg/d and 3 mm, respectively (P
- Published
- 2017
13. Evolvability and robustness: A paradox restored
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Christine Mayer and Thomas F. Hansen
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0106 biological sciences ,0301 basic medicine ,Statistics and Probability ,Evolutionary capacitance ,Biology ,Positive correlation ,010603 evolutionary biology ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Evolution, Molecular ,03 medical and health sciences ,Genetic Association Studies ,Genetics ,Neutral network ,Generality ,Models, Genetic ,General Immunology and Microbiology ,Applied Mathematics ,Robustness (evolution) ,General Medicine ,Biological Evolution ,Evolvability ,030104 developmental biology ,Boolean network ,Evolutionary biology ,Large networks ,Modeling and Simulation ,Nerve Net ,General Agricultural and Biological Sciences - Abstract
Evolvability and robustness are crucial for the origin and maintenance of complex organisms, but may not be simultaneously achievable as robust traits are also hard to change. Andreas Wagner has proposed a solution to this paradox by arguing that the many-to-few aspect of genotype-phenotype maps creates neutral networks of genotypes coding for the same phenotype. Phenotypes with large networks are genetically robust, but they may also have more neighboring phenotypes and thus higher evolvability. In this paper, we explore the generality of this idea by sampling large numbers of random genotype-phenotype maps for Boolean genotypes and phenotypes. We show that there is indeed a preponderance of positive correlations between the evolvability and robustness of phenotypes within a genotype-phenotype map, but also that there are negative correlations between average evolvability and robustness across maps. We interpret this as predicting a positive correlation across the phenotypic states of a character, but a negative correlation across characters. We also argue that evolvability and robustness tend to be negatively correlated when phenotypes are measured on ordinal or higher scale types. We conclude that Wagner's conjecture of a positive relation between robustness and evolvability is based on strict and somewhat unrealistic biological assumptions.
- Published
- 2017
14. Comparable cortisol, heart rate and milk let-down in nurse sows and non-nurse sows
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L.H. Diness, G. Sørensen, Charlotte Amdi, C. F. Hansen, V. A. Moustsen, K.B. Eriksson, Emma M. Baxter, L. C. Oxholm, and M.B.F. Nielsen
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Litter (animal) ,Saliva ,Milk Let-down ,General Veterinary ,business.industry ,animal diseases ,05 social sciences ,0402 animal and dairy science ,food and beverages ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,fluids and secretions ,Animal science ,medicine.anatomical_structure ,Nursing ,Lactation ,Heart rate ,medicine ,Weaning ,Cross-fostering ,0501 psychology and cognitive sciences ,Animal Science and Zoology ,050102 behavioral science & comparative psychology ,business ,Cortisol level - Abstract
Increasing litter size in hyperprolific sows has led to the need for management systems for surplus piglets, one of which is the use of nurse sows. The aim of this study was to investigate physiological changes in salivary cortisol, heart rate and number of milk let-downs in nurse sows compared to non-nurse sows. Sows were divided into three treatments: 1) control (non-nurse) sows nursed their own piglets until weaning at 26 days of age; 2) nurse1 sows had their own piglets removed and replaced with newborn piglets (between 6−24 h old) at Day 7, these were weaned at Day 33 of the sow's lactation period and 3) nurse2 sows weaned their own piglets at Day 21 and received a litter of 7 day old piglets from a nurse1 sow. These new piglets were weaned at Day 40 of the nurse2 sow's lactation period. Saliva samples were collected for cortisol analyses and the sows were fitted with pulse belts to monitor heart rate. Cameras were placed above the pens to record milk let-downs. Overall, there was no influence of treatment on salivary cortisol, heart rate or the number of milk let-downs/h. There was an effect of time as cortisol levels fell throughout lactation (P
- Published
- 2017
15. Confinement of sows 24h before expected farrowing affects the performance of nest building behaviours but not progress of parturition
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Sandra Edwards, J. Hales, C. F. Hansen, V. A. Moustsen, and Pernille M. Weber
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Veterinary medicine ,05 social sciences ,0402 animal and dairy science ,Free access ,04 agricultural and veterinary sciences ,Biology ,040201 dairy & animal science ,Observational period ,Animal science ,Food Animals ,Nest ,0501 psychology and cognitive sciences ,Animal Science and Zoology ,050102 behavioral science & comparative psychology - Abstract
The effects of confinement prior to farrowing on the performance of nest building behaviour and progress of parturition were investigated using hyper prolific sows. Forty first parity and 41 second/third parity sows were allocated to one of two treatments: loose housed (40) or confined (41). All sows had free access to a straw rack with long stemmed straw and were housed in a freedom farrowing pen with an option of confinement. Loose sows were loose housed throughout the observational period and confined sows were confined from 2 days before expected farrowing until the completion of parturition. Sows were video recorded from 2 days before expected farrowing until birth of the last piglet, and behaviours (biting/rooting pen fittings, straw directed and rooting/pawing floor) and postures (lying sternal, lying lateral, sitting and standing/walking) of the sows during the last 24 h before farrowing were recorded continuously. The time of birth of every piglet was recorded from the video recordings, and it was noted if the piglet was alive or stillborn. Treatments were compared by use of linear models with treatment and parity as fixed effects. Results showed that confinement did not influence duration of the nest building period, but affected the performance of nest building behaviour. Loose housed sows tended to perform more nest building behaviour during the nest building period than confined sows (817 (95% CI: 713–929) vs 686 (590–789) s/h/sow, P = 0.08). Loose housed sows had fewer bouts of nest building behaviours than confined sows (4.6 ± 0.48 vs 6.1 ± 0.48 bouts/sow/h, P = 0.03) but mean duration of bouts was longer (154 (95% CI: 136–173) vs 98 (83–114) s/bout, P
- Published
- 2017
16. Early and non-intrusive lameness detection in dairy cows using 3-dimensional video
- Author
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Lyndon N. Smith, K. Abdul Jabbar, Melvyn L. Smith, and Mark F. Hansen
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040301 veterinary sciences ,business.industry ,Video capture ,Dairy herds ,Computer science ,Centre for Machine Vision ,0402 animal and dairy science ,Soil Science ,Early detection ,Pattern recognition ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,Milking ,0403 veterinary science ,Support vector machine ,3D computer vision, early lameness detection, gait asymmetry, locomotion analysis ,Gait asymmetry ,Binary classification ,Control and Systems Engineering ,Lameness ,Artificial intelligence ,business ,Agronomy and Crop Science ,Simulation ,Food Science - Abstract
© 2016 IAgrE Lameness is a major issue in dairy herds and its early and automated detection offers animal welfare benefits together with potentially high commercial savings for farmers. Current advancements in automated detection have not achieved a sensitive measure for classifying early lameness. A novel proxy for lameness using 3-dimensional (3D) depth video data to analyse the animal's gait asymmetry is introduced. This dynamic proxy is derived from the height variations in the hip joint during walking. The video capture setup is completely covert and it facilitates an automated process. The animals are recorded using an overhead 3D depth camera as they walk freely in single file after the milking session. A 3D depth image of the cow's body is used to automatically track key regions such as the hooks and the spine. The height movements are calculated from these regions to form the locomotion signals of this study, which are analysed using a Hilbert transform. Our results using a 1–5 locomotion scoring (LS) system on 22 Holstein Friesian dairy cows, a threshold could be identified between LS 1 and 2 (and above). This boundary is important as it represents the earliest point in time at which a cow is considered lame, and its early detection could improve intervention outcome thereby minimising losses and reducing animal suffering. Using a linear Support Vector Machine (SVM) binary classification model, the threshold achieved an accuracy of 95.7% with a 100% sensitivity (detecting lame cows) and 75% specificity (detecting non-lame cows).
- Published
- 2017
17. A reduced CP level without medicinal zinc oxide does not alter the intestinal morphology in weaned pigs 24 days post-weaning
- Author
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Jens Nielsen, Anni Øyan Pedersen, Julie C Lynegaard, Christina Larsen, C. F. Hansen, Charlotte Amdi, and N.J. Kjeldsen
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Dietary protein ,medicine.medical_specialty ,Low protein ,Brush border ,Swine ,040301 veterinary sciences ,medicine.medical_treatment ,Weaning ,Urine ,Biology ,SF1-1100 ,0403 veterinary science ,Animal science ,Low-protein diet ,Intestine, Small ,Diet, Protein-Restricted ,medicine ,Animals ,Blood urea nitrogen ,0402 animal and dairy science ,04 agricultural and veterinary sciences ,Animal Feed ,040201 dairy & animal science ,Small intestine ,Diet ,Animal culture ,medicine.anatomical_structure ,Intestinal brush border ,Dietary Supplements ,Intestinal histopathology ,Animal Science and Zoology ,Histopathology ,Zinc Oxide - Abstract
The use of medicinal zinc oxide (ZnO) to prevent diarrhoea post-weaning will be banned in the EU from 2022. Therefore, new alternatives are needed to avoid an increase in diarrhoea and higher antibiotic use. A low dietary CP level has shown to lower the frequency of diarrhoea in pigs, due to lower microbial protein fermentation in the colon as well as improved conditions in the small intestine after weaning. The objective of this study was to examine the effect of decreased CP levels post-weaning as an alternative to medicinal ZnO on gut morphology and histopathology. Five hundred and sixty pigs were randomly assigned into one of six groups receiving a two-phase diet from 5.5 to 15 kg: positive control group (PC) with medicinal ZnO and standard levels of protein (19.1–18.4% CP), negative control group (NC) without medicinal ZnO and standard levels of protein (19.1–18.4% CP). The remaining four low protein groups were a low-standard (LS) CP level (16.6–18.4% CP), a low-low (LL) CP level (16.6–16.2% CP), a very low-high (VLH) CP level (14–19.3% CP) and a very low-medium (VLM) CP level (14–17.4% CP). Individual BW was recorded at day 0, 10 and 24 post-weaning, and all antibiotic treatments were recorded. Tissue samples from the small intestine (mid-jejunum) for morphological and histopathologic analysis, organ weights, blood and urine samples were collected at day 10 and 24 post-weaning from a total of 90 sacrificed weaners. The results demonstrated no differences in intestinal morphology between groups, but the histopathology showed a damaged brush border score in VLM and VLH pigs . In addition, a lower blood urea nitrogen in VLM pigs at 24 days was found. The LL and VLM pigs had a significantly decreased average daily gain in the overall trial period compared to PC and NC pigs. Conclusively, intestinal brush border was damaged by the very low protein diet at 24 days post-weaning, but intestinal morphology was unaffected by dietary strategy.
- Published
- 2021
18. The effect of temporary confinement of hyperprolific sows in Sow Welfare and Piglet protection pens on sow behaviour and salivary cortisol concentrations
- Author
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V. A. Moustsen, J. Hales, M. B. F. Nielsen, and C. F. Hansen
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Veterinary medicine ,040301 veterinary sciences ,animal diseases ,media_common.quotation_subject ,0402 animal and dairy science ,food and beverages ,04 agricultural and veterinary sciences ,Biology ,040201 dairy & animal science ,0403 veterinary science ,fluids and secretions ,Animal science ,medicine.anatomical_structure ,Food Animals ,Lactation ,medicine ,Weaning ,Gestation ,Animal Science and Zoology ,Welfare ,Salivary cortisol ,media_common - Abstract
The aim of this study was to investigate effects of confinement in Sow Welfare and Piglet protection pens (SWAP pen) for four days after farrowing on sow behaviour and salivary cortisol levels. Sows were randomly allocated to three treatments: loose-loose (LL), loose-confined (LC) or confined-confined (CC). Sows in LL were loose housed when they entered the farrowing unit until weaning. Sows in LC were loose housed to the end of farrowing and then confined to day 4 of lactation. Sows in CC were confined from day 114 of gestation to day 4 after farrowing. All sows were loose housed from day 4 to weaning. Regardless of treatment, sow behaviour was characterized by a low frequency of postural changes (
- Published
- 2016
19. Status epilepticus stimulates NDEL1 expression via the CREB/CRE pathway in the adult mouse brain
- Author
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Kelin L. Wheaton, Paul Horning, Sydney Aten, Katelin F. Hansen, Karl Obrietan, Kari R. Hoyt, Boyoung Lee, Yun Sik Choi, and Soren Impey
- Subjects
0301 basic medicine ,Nervous system ,Neurite ,Green Fluorescent Proteins ,Central nervous system ,Mice, Transgenic ,Biology ,CREB ,Article ,03 medical and health sciences ,Immunolabeling ,Prosencephalon ,Status Epilepticus ,Downregulation and upregulation ,medicine ,Animals ,Humans ,Cyclic AMP Response Element-Binding Protein ,Neurons ,General Neuroscience ,Pilocarpine ,Mice, Inbred C57BL ,Disease Models, Animal ,030104 developmental biology ,medicine.anatomical_structure ,Forebrain ,biology.protein ,Neuroglia ,Carrier Proteins ,Neuroscience - Abstract
Nuclear distribution element-like 1 (NDEL1/NUDEL) is a mammalian homolog of the Aspergillus nidulans nuclear distribution molecule NudE. NDEL1 plays a critical role in neuronal migration, neurite outgrowth and neuronal positioning during brain development; however within the adult central nervous system, limited information is available regarding NDEL1 expression and functions. Here, the goal was to examine inducible NDEL1 expression in the adult mouse forebrain. Immunolabeling revealed NDEL1 within the forebrain, including the cortex and hippocampus, as well as the midbrain and hypothalamus. Expression was principally localized to perikarya. Using a combination of immunolabeling and RNA seq profiling, we detected a marked and long-lasting upregulation of NDEL1 expression within the hippocampus following a pilocarpine-evoked repetitive seizure paradigm. Chromatin immunoprecipitation (ChIP) analysis identified a cAMP response element-binding protein (CREB) binding site within the CpG island proximal to the NDEL1 gene, and in vivo transgenic repression of CREB led to a marked downregulation of seizure-evoked NDEL1 expression. Together these data indicate that NDEL1 is inducibly expressed in the adult nervous system, and that signaling via the CREB/CRE transcriptional pathway is likely involved. The role of NDEL1 in neuronal migration and neurite outgrowth during development raises the interesting prospect that inducible NDEL1 in the mature nervous system could contribute to the well-characterized structural and functional plasticity resulting from repetitive seizure activity.
- Published
- 2016
20. Reproductive performance of 'nurse sows' in Danish piggeries
- Author
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C. F. Hansen, T. S. Bruun, Charlotte Amdi, A. B. Strathe, M. Schop, and Jens Vinther
- Subjects
Litter (animal) ,Veterinary medicine ,Litter Size ,Swine ,040301 veterinary sciences ,Denmark ,animal diseases ,Biology ,Reproductive cycle ,0403 veterinary science ,Danish ,Animal science ,Food Animals ,Nursing ,Pregnancy ,Lactation ,medicine ,Animals ,Weaning ,Animal Husbandry ,Small Animals ,Estrous cycle ,Equine ,0402 animal and dairy science ,food and beverages ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,language.human_language ,medicine.anatomical_structure ,language ,Female ,Animal Science and Zoology - Abstract
The use of nurse sows in Danish piggeries is common practice because of large litter sizes; however, the effect of being selected as a nurse sow on subsequent reproductive performance is unknown. Therefore, the aim of this study was to quantify a nurse sow's reproductive performance in the subsequent litter. Nurse sows were defined as sows weaning their own litter at least 18 days postpartum and thereafter nursing another litter (nurse litter) before service. Data (2012-2013) from 20 piggeries with more than 14.5 live born piglets per litter and a stable distribution of sows among parities over time were selected. Records from 79,864 litters were obtained and analyzed using mixed linear and logistic regression models. The average lactation lengths were 40.3 days for nurse sows and 27.8 days for non-nurse (normal) sows. Nurse sows weaned on average 12.4 piglets and subsequently 11.5 nurse piglets, whereas non-nurse weaned 11.7 piglets in their single weaning. There was no difference in re-service rate between nurse and non-nurse sows in the subsequent reproductive cycle. Subsequent litter size in the next reproductive cycle was higher for nurse sows than that for non-nurse sows (18.69 vs. 18.11 total born piglets; P 0.001). Nurse sows were of a slightly lower parity than non-nurse sows (3.12 vs. 3.27, P 0.001), and nurse sows had an increased weaning to estrus interval compared to non-nurse sows (4.23 vs. 4.19 days, P 0.001). The results indicate that nurse sows were selected among sows nursing large litters and could therefore suggest that these sows represent the best percentile of sows in a given piggery. In conclusion, this survey indicated no negative effects of being selected as a nurse sow on the subsequent reproductive performance. On the contrary, nurse sows gave birth to more piglets compared to non-nurse sows in their subsequent litter.
- Published
- 2016
21. Evolutionary modeling and correcting for observation error support a 3/5 brain-body allometry for primates
- Author
-
Kjetil L. Voje, Thomas F. Hansen, and Mark Grabowski
- Subjects
Primates ,0106 biological sciences ,0301 basic medicine ,Physiology ,Macroevolution ,Biology ,Models, Biological ,010603 evolutionary biology ,01 natural sciences ,03 medical and health sciences ,Phylogenetics ,Animals ,Body Size ,Phylogeny ,Ecology, Evolution, Behavior and Systematics ,Fossils ,Encephalization ,Brain ,Organ Size ,Encephalization quotient ,Phylogenetic comparative methods ,Biological Evolution ,030104 developmental biology ,Human evolution ,Evolutionary biology ,Anthropology ,Brain size ,Allometry - Abstract
The tight brain-body allometry across mammals and primates has motivated and informed many hypotheses about brain evolution in humans and other taxa. While a 2/3 or a 3/4 scaling is often at the core of such research, such exponents are derived from estimates based on particular statistical and evolutionary assumptions without careful consideration of how either may influence findings. Here we quantify primate brain-body allometry using phylogenetic comparative methods based on models of both adaptive and constrained evolution, and estimate and account for observational error in both response and predictor variables. Our results supported an evolutionary model in which brain size is directly constrained to evolve in unison with body size, rather than adapting to changes in the latter. The effects of controlling for phylogeny and observation error were substantial, and our analysis yielded a novel 3/5 scaling exponent for primate brain-body evolutionary allometry. Using this exponent with the latest brain- and body-size estimates to calculate new encephalization quotients for apes, humans, and fossil hominins, we found early hominins were substantially more encephalized than previously thought.
- Published
- 2016
22. F-value Calculator – A Tool for Calculation of Acceptable F-value in Canned Luncheon Meat Reduced in NaCl
- Author
-
F. Hansen, Claus Borggaard, and Annemarie Gunvig
- Subjects
Luncheon meat ,Canned luncheon meat ,aqueous salt ,C. botulinum ,food and beverages ,04 agricultural and veterinary sciences ,General Medicine ,040401 food science ,predictive model ,0404 agricultural biotechnology ,Value (economics) ,Food science ,F-value ,Mathematics - Abstract
Canned meat products are usually protected against C. botulinum by combinations of heat, NaCl and NaNO2. When meat products are reduced in NaCl for health reasons, they need a higher heat treatment to maintain same level of protection against C. botulinum. We describe a new tool for calculating the F-value, necessary to obtain equivalent safety for canned meat when reduced in NaCl, compared to the original combination of aqueous salt and F–value. The tool is valid for combinations of F–values between 0.51 and 3.25 and aqueous salt between 1.66 and 3.54%. The tool is available at http://dmripredict.dk.
- Published
- 2016
23. Microfiltration of raw milk for production of high-purity milk fat globule membrane material
- Author
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Sean A. Hogan, Steffen F. Hansen, Lars Wiking, Jan T. Rasmussen, John T. Tobin, and Lotte Bach Larsen
- Subjects
Chromatography ,Chemistry ,Microfiltration ,Extraction (chemistry) ,Pasteurization ,04 agricultural and veterinary sciences ,Raw milk ,Permeation ,040401 food science ,law.invention ,03 medical and health sciences ,0404 agricultural biotechnology ,0302 clinical medicine ,Membrane ,law ,030221 ophthalmology & optometry ,Globules of fat ,Filtration ,Food Science - Abstract
Commercial ingredients containing milk fat globule membrane (MFGM) material are currently isolated from heavily processed dairy streams. The aim of this study was to achieve a more gentle isolation of MFGM material by means of ceramic dia-microfiltration of raw whole milk to separate fat globules from casein micelles and whey proteins prior to MFGM extraction. A pilot-scale experiment with 1.4 μm pore size (membrane surface area 1.05 m 2) resulted in an optimal outcome of low permeation of fat (2.5% permeation) and high permeation of proteins (97% permeation). This yielded an MFGM isolate with 7% w/w polar lipids and 30% w/w proteins, where contamination of non-MFGM proteins was only 25% of total protein content. Furthermore, mild pasteurization (72 °C, 15 s) introduced either before or after microfiltration had no impact on filtration efficiency or MFGM yield and composition. The work describes an industrially relevant production method for a less-processed MFGM material of high purity with potential for further separation and valorisation of protein-rich permeate streams.
- Published
- 2020
24. Image segmentation of underfloor scenes using a mask regions convolutional neural network with two-stage transfer learning
- Author
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Mathew Holloway, Wenhao Zhang, Mark F. Hansen, Ashley Napier, and Gary A. Atkinson
- Subjects
Training set ,Computer science ,business.industry ,Deep learning ,0211 other engineering and technologies ,Convolutional neural network ,020101 civil engineering ,02 engineering and technology ,Building and Construction ,Image segmentation ,Underfloor maintenance ,0201 civil engineering ,Robotic systems ,Control and Systems Engineering ,021105 building & construction ,RGB color model ,Robot ,Computer vision ,Artificial intelligence ,business ,Transfer of learning ,Civil and Structural Engineering - Abstract
© 2020 Elsevier B.V. Enclosed spaces are common in built structures but pose a challenge to many forms of manual or robotic surveying and maintenance tasks. Part of this challenge is to train robot systems to understand their environment without human intervention. This paper presents a method to automatically classify features within a closed void using deep learning. Specifically, the paper considers a robot placed under floorboards for the purpose of autonomously surveying the underfloor void. The robot uses images captured using an RGB camera to identify regions such as floorboards, joists, air vents and pipework. The paper first presents a standard mask regions convolutional neural network approach, which gives modest performance. The method is then enhanced using a two-stage transfer learning approach with an existing dataset for interior scenes. The conclusion from this work is that, even with limited training data, it is possible to automatically detect many common features of such areas.
- Published
- 2020
25. The DendroEcological Network: A cyberinfrastructure for the storage, discovery and sharing of tree-ring and associated ecological data
- Author
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Alexandra Kosiba, James Duncan, Paula F. Murakami, Shelly A. Rayback, Christopher F. Hansen, and Paul G. Schaberg
- Subjects
0106 biological sciences ,010504 meteorology & atmospheric sciences ,Ecology ,Computer science ,media_common.quotation_subject ,Ecological data ,Plant Science ,Conservation communities ,01 natural sciences ,Data science ,Cyberinfrastructure ,Data transparency ,Scale (social sciences) ,Leverage (statistics) ,Quality (business) ,010606 plant biology & botany ,0105 earth and related environmental sciences ,media_common - Abstract
The DendroEcological Network (DEN; https://www.uvm.edu/femc/dendro) is an opensource repository of high quality dendrochronological and associated ecological data. Launched in 2018, the mission of the DEN is to provide a centralized, standards-driven cyberinfrastructure for data storage, exploration and sharing. Specifically, the objectives of the DEN are to, 1) act as an integrator of dendrochronological and ecological data, 2) facilitate synthetic investigation and analyses of these data, 3) uphold the scientific community’s goals of data transparency and reproducibility of results, 4) serve as a long-term data archiving platform for use by individuals, laboratories and the greater scientific, management and conservation communities and, 5) leverage and extend previous and future research. The DEN facilitates the gathering of individual studies into a larger network, expanding the scale of inquiry to address pressing ecological questions that no single study can answer alone.
- Published
- 2020
26. Determination of protein and amino acid requirements of lactating sows using a population-based factorial approach
- Author
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Ermias Kebreab, A.B. Strathe, Peter Kappel Theil, A. V. Strathe, and C. F. Hansen
- Subjects
Litter (animal) ,medicine.medical_specialty ,Factorial ,Litter Size ,Dairy & Animal Science ,Swine ,Energy balance ,Population based ,Models, Biological ,SF1-1100 ,Animal science ,Models ,Internal medicine ,Lactation ,medicine ,Animals ,Computer Simulation ,Amino Acids ,Adiposity ,Mathematics ,chemistry.chemical_classification ,Agricultural and Veterinary Sciences ,Lysine ,Population variation ,Nutritional Requirements ,protein requirement ,dietary recommendations ,Biological Sciences ,Biological ,Animal culture ,Diet ,lactating sows ,Amino acid ,Milk ,Endocrinology ,medicine.anatomical_structure ,chemistry ,amino acid requirements ,Energy density ,Female ,Animal Nutritional Physiological Phenomena ,Animal Science and Zoology ,Energy Metabolism ,Monte Carlo Method ,between-animal variation - Abstract
© The Animal Consortium 2015. Determination of appropriate nutritional requirements is essential to optimize the productivity and longevity of lactating sows. The current recommendations for requirements do not consider the large variation between animals. Therefore, the aim of this study was to determine the amino acid recommendations for lactating sows using a stochastic modeling approach that integrates population variation and uncertainty of key parameters into establishing nutritional recommendations for lactating sows. The requirement for individual sows was calculated using a factorial approach by adding the requirement for maintenance and milk. The energy balance of the sows was either negative or zero depending on feed intake being a limiting factor. Some parameters in the model were sow-specific and others were population-specific, depending on state of knowledge. Each simulation was for 1000 sows repeated 100 times using Monte Carlo simulation techniques. BW, back fat thickness of the sow, litter size (LS), average litter gain (LG), dietary energy density and feed intake were inputs to the model. The model was tested using results from the literature, and the values were all within ±1 s.d. of the estimated requirements. Simulations were made for a group of low- (LS = 10 (s.d. = 1), LG = 2 kg/day (s.d. = 0.6)), medium- (LS = 12 (s.d. = 1), LG = 2.5 kg/day (s.d. = 0.6)) and high-producing (LS = 14 (s.d. = 1), LG = 3.5 kg/day (s.d. = 0.6)) sows, where the average requirement was the result. In another simulation, the requirements were estimated for each week of lactation. The results were given as the median and s.d. The average daily standardized ileal digestible (SID) protein and lysine requirements for low-, medium- and high-producing sows were 623 (CV = 2.5%) and 45.1 (CV = 4.8%); 765 (CV = 4.9%) and 54.7 (CV = 7.0%); and 996 (CV = 8.5%) and 70.8 g/day (CV = 9.6%), respectively. The SID protein and lysine requirements were lowest at week 1, intermediate at week 2 and 4 and the highest at week 3 of lactation. The model is a valuable tool to develop new feeding strategies by taking into account the variable requirement between groups of sows and changes during lactation. The inclusion of between-sow variation gives information on safety margins when developing new dietary recommendations of amino acids and protein for lactating sows.
- Published
- 2015
27. Comparable farrowing progress in confined and loose housed hyper-prolific sows
- Author
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A.M. Devreese, J. Hales, M.B.F. Nielsen, C. F. Hansen, and V. A. Moustsen
- Subjects
Birth intervals ,Veterinary medicine ,medicine.anatomical_structure ,Animal science ,General Veterinary ,Lactation ,medicine ,Weaning ,Animal Science and Zoology ,Biology - Abstract
The aim of this study was to determine the effect of confinement from day 114 of gestation and the first four lactation days on farrowing progress and piglet survival. All sows (parity 1–7) were randomly allocated to one of the four treatment groups: confined–confined (CC, n =30), confined–loose (CL, n =32), loose–confined (LC, n =28) or loose–loose (LL, n =30). Before and during farrowing sows in CC and CL were confined in crates whereas sows in LC and LL were loose housed in this period. The first four days after farrowing sows in CC and LC were confined in crates whereas sows in CL and LL were loose housed during this time. All sows were loose housed from day 4 until weaning. Compared to loose sows (LC and LL), confinement before and during farrowing (CC and CL) did not affect total born piglets ( P =0.69), stillborn piglets ( P =0.68), farrowing duration ( P =0.26) or birth interval ( P =0.25). However, birth duration for stillborn piglets tended ( P =0.06) to be shorter in the loose housed sows than in confined sows. Loose housed sows with short farrowing duration ( P =0.06) to have fewer stillborns than confined sows with short farrowing duration. However, number of stillborn piglets increased with increasing farrowing duration for loose housed sows ( P P P P =0.10) to have greater piglet mortality than sows in LL. In conclusion, confinement from day 114 of gestation until birth of last piglet did not affect farrowing progress compared to sows that were loose housed. However, the results suggested that confinement of sows for four days after farrowing reduced piglet mortality compared to loose housed sows.
- Published
- 2015
28. Atheroprotective immunization with malondialdehyde-modified LDL is hapten specific and dependent on advanced MDA adducts: implications for development of an atheroprotective vaccine
- Author
-
Maripat Corr, Xuchu Que, Lotte F. Hansen, Dimitrios Tsiantoulas, Michael S. VanNieuwenhze, Meng-Yun Chou, Christoph J. Binder, Erica N. Montano, Philipp Wiesner, Karsten Hartvigsen, Sotirios Tsimikas, Ayelet Gonen, William W. Turner, Apaїs Rafia, and Joseph L. Witztum
- Subjects
Male ,Immunogen ,Biology ,Biochemistry ,Epitope ,Mice ,chemistry.chemical_compound ,Th2 Cells ,Endocrinology ,Immune system ,Antigen ,Malondialdehyde ,Animals ,Humans ,Research Articles ,Mice, Knockout ,Immunity, Cellular ,Vaccines ,Albumin ,Cell Biology ,Atherosclerosis ,Immunity, Humoral ,Lipoproteins, LDL ,chemistry ,Immunization ,Immunology ,Haptens ,Hapten - Abstract
Immunization with homologous malondialdehyde (MDA)-modified LDL (MDA-LDL) leads to atheroprotection in experimental models supporting the concept that a vaccine to oxidation-specific epitopes (OSEs) of oxidized LDL could limit atherogenesis. However, modification of human LDL with OSE to use as an immunogen would be impractical for generalized use. Furthermore, when MDA is used to modify LDL, a wide variety of related MDA adducts are formed, both simple and more complex. To define the relevant epitopes that would reproduce the atheroprotective effects of immunization with MDA-LDL, we sought to determine the responsible immunodominant and atheroprotective adducts. We now demonstrate that fluorescent adducts of MDA involving the condensation of two or more MDA molecules with lysine to form malondialdehyde-acetaldehyde (MAA)-type adducts generate immunodominant epitopes that lead to atheroprotective responses. We further demonstrate that a T helper (Th) 2-biased hapten-specific humoral and cellular response is sufficient, and thus, MAA-modified homologous albumin is an equally effective immunogen. We further show that such Th2-biased humoral responses per se are not atheroprotective if they do not target relevant antigens. These data demonstrate the feasibility of development of a small-molecule immunogen that could stimulate MAA-specific immune responses, which could be used to develop a vaccine approach to retard or prevent atherogenesis.
- Published
- 2014
29. Higher preweaning mortality in free farrowing pens compared with farrowing crates in three commercial pig farms
- Author
-
J. Hales, M. B. F. Nielsen, C. F. Hansen, and V. A. Moustsen
- Subjects
piglet mortality ,Litter (animal) ,Sus scrofa ,loose sows ,Parturition ,Biology ,Animal husbandry ,SF1-1100 ,Housing, Animal ,Crate ,animal welfare ,Animal culture ,Animals, Suckling ,farrowing accommodation ,Animal science ,Pregnancy ,Linear Models ,Herd ,Animals ,Female ,Animal Science and Zoology ,Animal Husbandry ,Mortality ,Pig farms - Abstract
If loose-housed farrowing systems are to be an alternative to traditional farrowing crates, it is important that they can deliver the same production results as can be achieved in farrowing crates under commercial conditions. The aim of this study was to compare preweaning mortality in farrowing crates and free farrowing pens (FF-pens) within herds that had both systems. The study was conducted over 2 years in three commercial Danish herds that had FF-pens as well as traditional farrowing crates in their farrowing unit. Piglet mortality was analysed in two periods: before litter equalisation and after litter equalisation. Linear models were used to analyse effects of housing (crate or pen), herd (Herd A, B or C), parity (parities 1, 2, 3 to 4 or 5 to 8) as well as the effect of number of total born piglets on mortality before litter equalisation, and the effect of equalised litter size on piglet mortality after litter equalisation. All corresponding interactions were included in the models. Before litter equalisation piglet mortality was higher (P
- Published
- 2014
30. Quantifying the legacy of foliar winter injury on woody aboveground carbon sequestration of red spruce trees
- Author
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Alexandra Kosiba, Gary J. Hawley, Paul G. Schaberg, and Christopher F. Hansen
- Subjects
Aboveground carbon ,Crown (botany) ,Diameter at breast height ,Xylem ,Forestry ,Management, Monitoring, Policy and Law ,Biology ,Moderate temperature ,Basal area ,Animal science ,Botany ,Dominance (ecology) ,Tree health ,Nature and Landscape Conservation - Abstract
Red spruce (Picea rubens Sarg.) decline has been quantitatively attributed to foliar winter injury caused by freezing damage. The results of this injury include foliar mortality, crown deterioration, and negative carbon (C) balances that can lead to tree health declines and eventual mortality. In 2003, a severe region-wide event damaged over 90% of red spruce in the northeastern United States (US). We assessed the influence of the 2003 winter injury event on long-term growth and C sequestration of red spruce trees by measuring the xylem growth (basal area increment) in forest stands in Vermont (VT), New Hampshire (NH), and Massachusetts (MA) where winter injury was quantified in 2003. Although previous work reported 2 years of significant linear relationships between winter injury and growth declines, here we show that growth declines relative to pre-injury (average for 2001 and 2002) growth persisted for an additional (third) year. Using 3 years of significantly reduced growth, we estimated that the 2003 winter injury event reduced the regional C sequestration of red spruce trees >17.78 cm diameter at breast height (DBH) by about 673,000 metric tons (t) of C (approximately 2,465,000 t of CO2) - approximately 70% larger than the previous estimate. Because winter injury in 2003 was positively and significantly related to plot elevation, we also examined relative changes in red spruce growth for three elevation groups: low (920 m). Relative growth was below pre-injury levels and significantly less for high compared to low elevation groups from 2003 to 2006, after which growth between these groups was indistinguishable through 2010. In 2007, and continuing through 2010, trees in mid-elevation plots exhibited significantly higher growth relative to pre-winter injury levels. Eight years after the winter injury event, mid-elevation plots had significantly higher net growth than high elevation plots and had rebounded from growth declines following the 2003 winter injury event. As of 2010, trees in the high elevation plots continued to show net C reductions - an enduring legacy of the 2003 winter injury event. The long-lasting reductions in growth subsequent to the 2003 winter injury event were followed by an unprecedented upsurge of growth in recent years, particularly in 2009 and 2010 at mid-elevation plots. This growth increase could reflect the dominance and established ecological niche of red spruce at these elevations, but it could also be influenced by more moderate temperature trends during fall through spring in recent years.
- Published
- 2013
31. Measurements of turbulent mixing due to Kelvin–Helmholtz instability in high-energy-density plasmas
- Author
-
C.C. Kuranz, H.-S. Park, Omar Hurricane, Bruce Remington, Christine Krauland, Dov Shvarts, David Martinez, J. F. Hansen, D. C. Marion, Y. Elbaz, R. J. Wallace, G. Langstaff, Harry Robey, Oleg Schilling, R. P. Drake, C. A. Di Stefano, A. Shimony, V. A. Smalyuk, and Kumar Raman
- Subjects
Shock wave ,Physics ,Nuclear and High Energy Physics ,Radiation ,business.industry ,Turbulence ,Mechanics ,Plasma ,Kinetic energy ,Instability ,Optics ,Surface roughness ,business ,FOIL method ,Mixing (physics) - Abstract
Kelvin–Helmholtz (KH) turbulent mixing measurements were performed in experiments on the OMEGA Laser Facility [T.R. Boehly et al., Opt. Commun. 133 (1997) 495]. In these experiments, laser-driven shock waves propagated through low-density plastic foam placed on top of a higher-density plastic foil. Behind the shock front, lower-density foam plasma flowed over the higher-density plastic plasma. The interface between the foam and plastic was KH unstable. The experiments were performed with pre-imposed, sinusoidal 2D perturbations, and broadband 3D perturbations due to surface roughness at the interface between the plastic and foam. KH instability growth was measured using X-ray, point-projection radiography. The mixing layer caused by the KH instability with layer width up to ∼100 μm was observed at a location ∼1 mm behind the shock front. The measured mixing layer width was in good agreement with simulations using a K–L turbulent mixing model in the two-dimensional ARES hydrodynamics code. In the definition of the K–L model K stands for the specific turbulent kinetic (K) energy, and L for the scale length (L) of the turbulence.
- Published
- 2013
32. A mathematical model for predicting growth/no-growth of psychrotrophic C. botulinum in meat products with five variables
- Author
-
C. Borggaard, Annemarie Gunvig, and F. Hansen
- Subjects
chemistry.chemical_compound ,Volume (thermodynamics) ,Chemistry ,C. botulinum ,Modified atmosphere ,Enumeration ,Sodium lactate ,Food science ,Sodium nitrite ,Food Science ,Biotechnology - Abstract
The objective of this study was to develop a mathematical model for predicting growth/no-growth of psychrotrophic Clostridium botulinum in pasteurised meat products packed in modified atmosphere for combinations of storage temperature, pH, NaCl, added sodium nitrite and sodium lactate. Data for developing and training the artificial neural network (ANN) were generated in meat products. A total of 249 growth experiments were carried out in three different meat products with different combinations of storage temperature, pH, NaCl, sodium nitrite and sodium lactate. The meat batter was inoculated with approx. 10 4 spores/g using a 4-strain cocktail of gas-producing C. botulinum . The meat products were sliced, packed in modified atmosphere (30% CO 2 /70% N 2 ) and stored at 4 °C, 8 °C and 12 °C, respectively, for up to 8 weeks. The enumeration of C. botulinum was performed when the volume of the package had increased by 9% or more, or at the end of the storage period. Based on 10–20 replicates for each combination, the “frequency of growth” was calculated. An ANN with 5 input neurons, 3 hidden and a single output neuron was trained using the 5 hurdle values as inputs and the observed “frequency of growth” as target value. The inputs for the final model are the five variables: temperature, pH, added sodium nitrite, NaCl and sodium lactate within the ranges 4–12 °C, 5.4–6.4, 0–150 ppm, 1.2–2.4% and 0–3% respectively. As reference a logistic regression method was also applied and subsequently compared to the full neural network model. Based on RMSEC value of 0.104 and 0.144 for ANN and the logistic regression model respectively, the ANN was preferred. On a separate set of test data ( n = 60) the ANN model was validated by comparing the predicted “probability of growth” with the observed growth. A bias of 0.0166 was obtained, indicative of a model that is slightly fail-safe.
- Published
- 2013
33. A phylogenetic comparative method for studying multivariate adaptation
- Author
-
Petter Mostad, Staffan Andersson, Thomas F. Hansen, Jason Pienaar, and Krzysztof Bartoszek
- Subjects
Male ,Statistics and Probability ,Multivariate statistics ,Comparative method ,Biology ,Models, Biological ,General Biochemistry, Genetics and Molecular Biology ,Statistics ,Animals ,Phylogeny ,Likelihood Functions ,Stochastic Processes ,General Immunology and Microbiology ,Phylogenetic tree ,Deer ,Applied Mathematics ,Body Weight ,Animal Structures ,Ornstein–Uhlenbeck process ,General Medicine ,Phylogenetic comparative methods ,Adaptation, Physiological ,Data set ,Modeling and Simulation ,Multivariate Analysis ,Female ,Allometry ,Adaptation ,General Agricultural and Biological Sciences - Abstract
Phylogenetic comparative methods have been limited in the way they model adaptation. Although some progress has been made, there are still no methods that can fully account for coadaptation between traits. Based on Ornstein-Uhlenbeck (OU) models of adaptive evolution, we present a method, with R implementation, in which multiple traits evolve both in response to each other and, as in previous OU models, to fixed or randomly evolving predictor variables. We present the interpretation of the model parameters in terms of evolutionary and optimal regressions enabling the study of allometric and adaptive relationships between traits. To illustrate the method we reanalyze a data set of antler and body-size evolution in deer (Cervidae).
- Published
- 2012
34. Potential role of soil calcium in recovery of paper birch following ice storm injury in Vermont, USA
- Author
-
Gary J. Hawley, Christopher F. Hansen, Joshua M. Halman, and Paul G. Schaberg
- Subjects
Betulaceae ,geography ,Marsh ,geography.geographical_feature_category ,Crown (botany) ,chemistry.chemical_element ,Forestry ,Management, Monitoring, Policy and Law ,Biology ,Calcium ,biology.organism_classification ,Ice storm ,Agronomy ,chemistry ,Soil water ,Forest ecology ,Botany ,Temperate climate ,Nature and Landscape Conservation - Abstract
In recent years, an increased number of mature paper birch (Betula papyrifera Marsh.) and heart-leafed paper birch (B. papyrifera var. cordifolia (Regel) Fern.) in northeastern United States forests have exhibited decline symptoms including foliar loss, reduced fine branching, and tree mortality. We assessed crown health, radial growth, and available soil cations in 2006 as a preliminary assessment of factors that may be influencing paper birch decline. Tree rings began to decrease in width in 1998--the year of a severe region-wide ice storm. All trees (regardless of their current decline status) experienced reduced growth starting in 1998 and tree growth continued to decrease for two years following the ice storm. After this generalized growth decrease, trees that now have vigorous crowns showed a marked increase in growth, whereas trees that now have low crown vigor did not rebound in growth, but instead exhibited a significantly higher incidence of locally absent annual rings. Extractable soil-aluminum (Al), a phytotoxic element mobilized by acid deposition, was significantly higher in soils associated with declining trees compared to those adjacent to vigorous trees. Higher soil calcium (Ca) availability was associated with both vigorous crowns and increased radial growth following the 1998 ice storm. Furthermore, increased soil Ca availability was negatively correlated to the percentage of declining trees, and positively related to increased radial growth, whereas elevation was not significantly associated with either parameter. Although previously overlooked as a factor influencing paper birch recovery from injury, we found that available soil Ca was linked to crown vigor and rebounds in growth following an inciting event.
- Published
- 2011
35. TRK wild-type and fusion protein expression in solid tumors: Characterization by immunohistochemistry and in situ hybridization
- Author
-
P. Thorne-Nuzzo, D. Morosini, A.N. Sireci, K. Ebata, J. Feng, L. Kivi, T.-S. Shen, F. Hansen, C. Kriegshauser, and Brian B. Tuch
- Subjects
business.industry ,Wild type ,Hematology ,In situ hybridization ,Molecular biology ,Fusion protein ,03 medical and health sciences ,0302 clinical medicine ,Oncology ,Fusion Protein Expression ,030220 oncology & carcinogenesis ,Trk receptor ,Medicine ,Immunohistochemistry ,030211 gastroenterology & hepatology ,business - Published
- 2018
36. 3D face reconstructions from photometric stereo using near infrared and visible light
- Author
-
Melvyn L. Smith, Lyndon N. Smith, Mark F. Hansen, and Gary A. Atkinson
- Subjects
Ground truth ,Brightness ,Pixel ,Computer science ,business.industry ,3D reconstruction ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Image processing ,Iterative reconstruction ,Photometry (optics) ,Photometric stereo ,Signal Processing ,Computer vision ,Computer Vision and Pattern Recognition ,Artificial intelligence ,business ,Software - Abstract
This paper seeks to advance the state-of-the-art in 3D face capture and processing via novel Photometric Stereo (PS) hardware and algorithms. The first contribution is a new high-speed 3D data capture system, which is capable of acquiring four raw images in approximately 20ms. The results presented in this paper demonstrate the feasibility of deploying the device in commercial settings. We show how the device can operate with either visible light or near infrared (NIR) light. The NIR light sources offer the advantages of being less intrusive and more covert than most existing face recognition methods allow. Furthermore, our experiments show that the accuracy of the reconstructions is also better using NIR light. The paper also presents a modified four-source PS algorithm which enhances the surface normal estimates by assigning a likelihood measure for each pixel being in a shadowed region. This likelihood measure is determined by the discrepancies between measured pixel brightnesses and expected values. Where the likelihood of shadow is high, then one light source is omitted from the computation for that pixel, otherwise a weighted combination of pixels is used to determine the surface normal. This means that the precise shadow boundary is not required by our method. The results section of the paper provides a detailed analysis of the methods presented and a comparison to ground truth. We also analyse the reflectance properties of a small number of skin samples to test the validity of the Lambertian model and point towards potential improvements to our method using the Oren-Nayar model.
- Published
- 2010
37. Decontamination of a rotating cutting tool during operation by means of atmospheric pressure plasmas
- Author
-
T. Jacobsen, Frank Leipold, F. Hansen, and Yukihiro Kusano
- Subjects
Materials science ,Atmospheric pressure ,Cutting tool ,Nuclear engineering ,education ,Human decontamination ,Plasma ,Dielectric barrier discharge ,Slicing ,surgical procedures, operative ,sense organs ,Plasma processing ,After treatment ,Food Science ,Biotechnology - Abstract
The decontamination of a rotating cutting tool used for slicing in the meat industry by means of atmospheric pressure plasmas is investigated. The target is Listeria monocytogenes, a bacterium which causes listeriosis and can be found in plants and food. The non-pathogenic species, Listeria innocua, is used for the experiments. A rotating knife was inoculated with L. innocua. The surface of the rotating knife was partly exposed to an atmospheric pressure dielectric barrier discharge operated in air, where the knife itself served as a ground electrode. The rotation of the knife ensures a treatment of the whole cutting tool. A log 5 reduction of L. innocua is obtained after 340 s of plasma operation. The temperature of the knife after treatment was found to be below 30 °C. The design of the setup allows a decontamination during slicing operation.
- Published
- 2010
38. The possible effects of magnetic fields on laser experiments of Rayleigh–Taylor instabilities
- Author
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A. R. Miles, J. P. Knauer, Michael Grosskopf, Tomasz Plewa, N. Hearn, A. Budde, C.C. Kuranz, Bruce Fryxell, R. P. Drake, and J. F. Hansen
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Physics ,Nuclear and High Energy Physics ,Radiation ,Computer simulation ,Richtmyer–Meshkov instability ,Astrophysics ,Mechanics ,Instability ,Magnetic field ,symbols.namesake ,symbols ,Rayleigh scattering ,Ejecta ,Blast wave ,Envelope (waves) - Abstract
The interaction of a blast wave generated in a supernova explosion with a composition discontinuity in the star's envelope produces crossed density and pressure gradients that are unstable to the growth of Rayleigh–Taylor modes. This instability is thought to be responsible for mixing of nuclear species in the ejecta and to produce observable effects in the light curve and spectrum of the explosion. Blast-wave-driven instabilities of this type have been studied extensively by numerical simulation as well as experimentally using the Omega Laser at the University of Rochester. Initial comparisons between the numerical simulations and the experiments show poor agreement. The simulations show the bubble and spike morphology of the classic Rayleigh–Taylor instability, with well-developed mushroom caps at the tips of the spikes. However, the mushroom caps seem to be completely absent from experiments with three-dimensional initial seed perturbations and are smaller than expected in two-dimensional experiments. Also, some experiments show mass extending beyond the spikes and penetrating almost to the shock front. This effect is completely absent from the numerical simulations. This paper discusses the possibility that the morphology of the instability is significantly altered by the generation of very strong magnetic fields during the laser experiments.
- Published
- 2010
39. Estimating genetic architectures from artificial-selection responses: A random-effect framework
- Author
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Hans J. Skaug, Thomas F. Hansen, and Arnaud Le Rouzic
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Genetic Research ,Maximum likelihood ,Breeding ,Biology ,Machine learning ,computer.software_genre ,Econometrics ,Animals ,Selection, Genetic ,Ecology, Evolution, Behavior and Systematics ,Selection (genetic algorithm) ,Likelihood Functions ,Models, Genetic ,business.industry ,Model selection ,Design of experiments ,Genetic Drift ,Genetic Variation ,Quantitative genetics ,Random effects model ,Genetic architecture ,Rats ,Phenotype ,Key (cryptography) ,Artificial intelligence ,business ,computer - Abstract
Artificial-selection experiments on plants and animals generate large datasets reporting phenotypic changes in the course of time. The dynamics of the changes reflect the underlying genetic architecture, but only simple statistical tools have so far been available to analyze such time series. This manuscript describes a general statistical framework based on random-effect models aiming at estimating key parameters of genetic architectures from artificial-selection responses. We derive explicit Mendelian models (in which the genetic architecture relies on one or two large-effect loci), and compare them with classical polygenic models. With simulations, we show that the models are accurate and powerful enough to provide useful estimates from realistic experimental designs, and we demonstrate that model selection is effective in picking few-locus vs. polygenic genetic architectures even from medium-quality artificial-selection data. The method is illustrated by the analysis of a historical selection experiment, carried on color pattern in rats by Castle et al.
- Published
- 2010
40. Biologically inspired 3D face recognition from surface normals
- Author
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Mark F. Hansen and Gary A. Atkinson
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Face hallucination ,3D face recognition ,Caricature ,Biometrics ,Computer science ,business.industry ,3D single-object recognition ,Dimensionality reduction ,Surface normals ,Facial recognition system ,Eigenface ,Face (geometry) ,Human visual system model ,Dimension reduction ,General Earth and Planetary Sciences ,Three-dimensional face recognition ,Computer vision ,Artificial intelligence ,Face detection ,business ,General Environmental Science - Abstract
A major consideration in state-of-the-art face recognition systems is the amount of data that is required to represent a face. Even a small (64×64) photograph of a face has 212 dimensions in which a face may sit. When large (>1 MB) photographs of faces are used, this represents a very large (and practically intractable) space and ways of reducing dimensionality without losing discriminatory information are needed for storing data for recognition. The eigenface technique, which is based upon Principal Components Analysis (PCA), is a well established dimension reduction method in face recognition research but does not have any biological basis. Humans excel at familiar face recognition and this paper attempts to show that modelling a biologically plausible process is a valid alternative approach to using eigenfaces for dimension reduction. Using a biologically inspired method to extract the certain facial discriminatory information which mirrors some of the idiosyncrasies of the human visual system, we show that recognition rates remain high despite 90% of the raw data being discarded.
- Published
- 2010
- Full Text
- View/download PDF
41. Baseline face recognition using photometric stereo data
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Melvyn L. Smith, Stefanos Zafeiriou, Mark F. Hansen, Gary A. Atkinson, and Maria Petrou
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3D face recognition ,Photometric stereo ,Computer science ,business.industry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Pattern recognition ,Facial recognition system ,Expression (mathematics) ,Session (web analytics) ,Range (mathematics) ,Face (geometry) ,Principal component analysis ,General Earth and Planetary Sciences ,Computer vision ,Artificial intelligence ,Baseline (configuration management) ,business ,General Environmental Science - Abstract
This research is motivated by the need for face recognition in uncontrolled environments. In other words, we are interested in face recognition arrangements whereby the users do not need to interact with the recognition technology. The contribution of this paper is to perform a range of recognition experiments on face image data as people casually enter a building, without any instructions about expression. Specifically, we capture four images per session in rapid succession (all within 20 ms). The four images are synchronised to different light sources to enable photometric stereo processing to estimate albedo images, surface normals and depth maps. Additional capture sessions then take place over periods of many weeks. Our recognition experiments are on each of the three modalities as well as a fusion technique for the albedo and depth. Using a variety of photometric stereo methods, surface integration methods (to recover depth) and recognition algorithms such as principal component analysis and nonnegative matrix factorisation, we acquire a maximum recognition rate of 86% for 96 subjects.
- Published
- 2010
42. Effects of Stronach Dam removal on fluvial geomorphology in the Pine River, Michigan, United States
- Author
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Jessica Mistak, Daniel B. Hayes, Kristi D. Klomp, Bryan A. Burroughs, and Jonathan F. Hansen
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Headward erosion ,Hydrology ,geography ,geography.geographical_feature_category ,Floodplain ,Dam removal ,Erosion ,Fluvial ,Sediment ,Geology ,Deposition (geology) ,Channel (geography) ,Earth-Surface Processes - Abstract
Although dam removal has been increasingly used as an option in dam management, and as a river restoration tool, few studies provide detailed quantitative assessment of the geomorphological response of rivers to dam removal. In this study, we document the response of the Pine River, Michigan, to the gradual removal of Stronach Dam. In 1996, prior to the initiation of removal, 31 permanent cross-sectional transects were established in the 10-km study area. These transects were surveyed annually during the course of the removal (1996–2003) and for the three years following removal (2004–2006). Dam removal resulted in progressive headcutting of sediments in the former impoundment, extending upstream 3.89 km of the dam. Over the course of the 10 years since dam removal was initiated, a net total of 92 000 m 3 of sediment erosion occurred. The majority of sediments stored in the former reservoir remained in place, with only 12% of the estimated reservoir sediment fill being eroded. Approximately 14% of the net erosion was deposited within the stream channel 1 km downstream of the dam location, with the remainder being transported further downstream or deposited in the floodplain. Sediment fill incision resulted in a narrower and deeper channel upstream, with higher mean water velocity and somewhat coarser substrates. Downstream deposition resulted in a wider and shallower channel, with little change in substrate size composition. Counter-intuitively, water velocity also increased downstream because of the increased slope that developed. Prior to removal, bedforms in the former impoundment were dominated by runs but are showing signs of restoration toward reference conditions. Continuing changes in river geomorphology are evident even three years following removal and are likely to occur for years to come.
- Published
- 2009
43. Using LiDAR data to map gullies and headwater streams under forest canopy: South Carolina, USA
- Author
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William F. Hansen, Darrell Glen Watson, and L. Allan James
- Subjects
Data set ,Canopy ,Tree canopy ,Lidar ,Aerial photography ,Vegetation ,Scale (map) ,Change detection ,Geology ,Earth-Surface Processes ,Remote sensing - Abstract
The southeastern Piedmont of the USA was severely gullied during the early 20th century. A thick canopy established by reforestation in many areas now inhibits the identification or mapping of gullies by aerial photography or other conventional remote sensing methods. An Airborne Laser-Scanning (ALS or LiDAR) mapping mission flown for the U.S. Forest Service in April, 2004 acquired bare-Earth topographic data. This paper tests the ability of the ALS topographic data to identify headwater channels and gullies for two branching gully systems in forested areas and to extract gully morphologic information. Comparisons are made with field traverses using differential GPS and reference cross sections measured by leveling surveys. At the gully network scale, LiDAR data provide accurate maps – the best available – with robust detection of small gullies except where they are narrow or parallel and closely spaced. Errors in mapping channel location and network topological connectivity under forest canopy increase with attempts to identify smaller features such as large rills. The ability of LiDAR data to map gullies and channels in a forested landscape should improve channel-network maps and topological models. At the gully reach scale, attempts to use LiDAR data to extract gully cross-section morphologic information under forest canopy were less successful due to systematic underestimation of gully depths and overestimation of gully top widths. Limited morphologic accuracy of the data set at this scale may be due to low bare-Earth point densities, shadowing of gully bottoms, and filtering of topographic discontinuities during post-processing. The ALS data used in this study are not suitable for detailed morphometric analysis or subtle change detection to monitor gullies or develop sediment budgets. Data collection may be improved by orienting flights over gullies and with increased point densities through improved scanner technology or better filtering and software capabilities to differentiate between vegetation and ground surfaces.
- Published
- 2007
44. Link between the diversity, heterogeneity and kinetic properties of amorphous ice structures
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R.P. May, Thomas F. Hansen, Helmut Schober, and Michael Marek Koza
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Diffraction ,Mesoscopic physics ,Chemistry ,Kinetics ,FOS: Physical sciences ,Disordered Systems and Neural Networks (cond-mat.dis-nn) ,Condensed Matter - Disordered Systems and Neural Networks ,Condensed Matter - Soft Condensed Matter ,Neutron scattering ,Condensed Matter Physics ,Small-angle neutron scattering ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Crystallography ,Chemical physics ,Amorphous ice ,Materials Chemistry ,Ceramics and Composites ,Soft Condensed Matter (cond-mat.soft) ,Structure factor - Abstract
Based on neutron wide-angle diffraction and small-angle neutron scattering experiments, we show that there is a correlation between the preparational conditions of amorphous ice structures, their microscopic structural properties, the extent of heterogeneities on a mesoscopic spatial scale and the transformation kinetics. There are only two modifications that can be identified as homogeneous disordered structures, namely the very high-density vHDA and the low-density amorphous LDA ice. Structures showing an intermediate static structure factor with respect to vHDA and LDA are heterogeneous phases. This holds independently from their preparation procedure, i.e. either obtained by pressure amorphization of ice I h or by heating of vHDA. The degree of heterogeneity can be progressively suppressed when higher pressures and temperatures are applied for the sample preparation. In accordance with the suppressed heterogeneity the maximum of the static structure factor displays a pronounced narrowing of the first strong peak, shifting towards higher Q -numbers. Moreover, the less heterogeneous the obtained structures are the slower is the transformation kinetics from the high-density modifications into LDA. The well known high-density amorphous structure HDA does not constitute any particular state of the amorphous water network. It is formed due to the preparational procedure working in liquid nitrogen as thermal bath, i.e. at about 77 K.
- Published
- 2006
45. Attitudes of faculty and students toward case-based learning in the third-year obstetrics and gynecology clerkship
- Author
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Wendy F. Hansen, Joel I Sorosky, C. Sipe, and Kristi J. Ferguson
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Clinical clerkship ,Educational measurement ,Faculty, Medical ,Students, Medical ,media_common.quotation_subject ,Teaching method ,education ,Specialty ,Presentation ,Obstetrics and gynaecology ,Humans ,Learning ,Medicine ,Prospective Studies ,media_common ,Medical education ,business.industry ,Clinical Clerkship ,Obstetrics and Gynecology ,Obstetrics ,Attitude ,Problem-based learning ,Gynecology ,Case-Control Studies ,Learning disability ,medicine.symptom ,business - Abstract
This study was undertaken to compare the attitudes of faculty and medical students toward case-based learning and lecture format during the obstetrics and gynecology clerkship.For this prospective comparative study, student presentations were alternately assigned to traditional lecture- or case-based format every 6 weeks. Presentations were made to other students and a single faculty. A total of 31 faculty members, 30 student presenters, and 122 student participants completed evaluations. Teaching methods were compared. RESULTS Faculty members favored lecture format over case-based learning for "attentiveness and interaction of the group" (3.9 vs 4.5, P.018) and for "meeting the objectives" (3.7 vs 4.5, P.002). Student participants favored case-based learning in "understanding the relationship between knowledge and clinical practice" (4.34 vs 4.06, P.05) and "enjoyed" (4.34 vs 3.90, P.008). Student presenters showed no differences between groups.Faculty favored lecture format whereas student participants favored a case-based presentation. Student presenters were comfortable with both formats.
- Published
- 2005
46. Pulsatile Wall Motion (PWM) Measurements after Endovascular Abdominal Aortic Aneurysm Exclusion are not Useful in the Classification of Endoleak
- Author
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Martin Malina, Timothy Resch, Krassi Ivancev, F Hansen, Nuno Dias, Björn Sonesson, and Bengt Lindblad
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Male ,medicine.medical_specialty ,Endoleak ,Movement ,Pulsatile flow ,chemical and pharmacologic phenomena ,Blood Vessel Prosthesis Implantation ,Aortic aneurysm ,medicine.artery ,medicine ,Humans ,Stent-graft ,Aorta, Abdominal ,Postoperative Period ,Prospective Studies ,Wall motion ,Long-term follow-up ,Aged ,Aged, 80 and over ,Medicine(all) ,Aorta ,business.industry ,medicine.disease ,Abdominal aortic aneurysm ,Prosthesis Failure ,Surgery ,Endovascular aneurysm reconstruction ,Pulsatile Flow ,Hemorheology ,Female ,Radiology ,Ultrasonography ,Cardiology and Cardiovascular Medicine ,business ,Pulse-width modulation ,Pulsatile wall motion ,Aortic Aneurysm, Abdominal ,Abdominal surgery - Abstract
The pulsatile wall motion (PWM) of AAA is reduced after endovascular stent-graft placement. The purpose of this study was to identify whether PWM after endografting was useful in the classification of endoleak. Patients and Methods 162 patients treated with EVAR underwent pre- and post-operative PWM assessment with ultrasonography. Follow-up was 1–9 years. 111 patients had well-excluded aneurysms, three patients had enlarging aneurysms without any recognizable endoleak (endotension), 16 had type I, 31 had type II and 1 had type III endoleak. Results The PWM was reduced from about 1 mm pre-operatively to 0.24 mm post-operatively in well-excluded aneurysms. PWM remained stable during follow-up. Type I endoleak was associated with moderately reduced PWM (proximal endoleak 0.79 mm and distal 0.32 mm). PWM in patients with type II endoleak was higher (0.32 mm) post-operatively ( p =0.002) compared to well-excluded aneurysms. Conclusion PWM is permanently reduced after endografting. The smallest reduction in PWM was in patients with type II endoleaks. However, the overlap between the groups does not allow reliable identification of patients having endoleak with PWM-measurements.
- Published
- 2004
47. Towards an international standard for PCR-based detection of foodborne thermotolerant campylobacters: interaction of enrichment media and pre-PCR treatment on carcass rinse samples
- Author
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Mathilde Hartmann Josefsen, Peter Stephensen Lübeck, Jeffrey Hoorfar, and F. Hansen
- Subjects
DNA, Bacterial ,Microbiology (medical) ,Meat ,DNA polymerase ,Pcr assay ,Diagnostic Specificity ,DNA-Directed DNA Polymerase ,medicine.disease_cause ,Polymerase Chain Reaction ,Sensitivity and Specificity ,Microbiology ,law.invention ,chemistry.chemical_compound ,law ,Campylobacter Infections ,medicine ,Animals ,Molecular Biology ,Polymerase chain reaction ,Chromatography ,biology ,Campylobacter ,Amplicon ,DNA extraction ,Molecular biology ,Culture Media ,Ducks ,PCR ,Enrichment ,chemistry ,Food ,Food Microbiology ,biology.protein ,Chickens ,Carcass rinse ,DNA - Abstract
As part of a large EU project for standardisation of polymerase chain reaction (PCR), a systematic evaluation of the interaction of enrichment media, type of DNA polymerase and pre-PCR sample treatment for a PCR detecting thermotolerant campylobacters was carried out. The growth-supporting capacity and PCR compatibility of enrichment in Preston, Mueller-Hinton and Bolton broth (blood-containing and blood-free) were evaluated. The effect of resin-based DNA extraction and DNA extraction by boiling on the final PCR assay was investigated. The time-course studies indicated that a 20-h sample enrichment in blood-containing Bolton broth, followed by a simple resin-based extraction of DNA and a PCR amplification using Tth polymerase, resulted in strong and clear PCR amplicons for target (287 bp) and internal amplification control (IAC, 124 bp). The enrichment PCR-based method, tested on 68 presumably naturally contaminated poultry-rinse samples, showed a diagnostic sensitivity of 97.5% (39 PCR-positive/40 total positive samples) and a diagnostic specificity of 100% (28 PCR-negative/28 total negative samples; P=0.32) when compared to a standard bacteriological method (ISO 10272).
- Published
- 2004
48. Processes leading to a spatial aggregation of Echinococcus multilocularis in its natural intermediate host Microtus arvalis
- Author
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Florian Jeltsch, Christoph Staubach, Kirsten Tackmann, F. Hansen, and Hans-Hermann Thulke
- Subjects
biology ,Arvicolinae ,Ecology ,Vulpes ,Host (biology) ,Species distribution ,Intermediate host ,Foxes ,Wildlife disease ,biology.organism_classification ,Spatial distribution ,Echinococcus multilocularis ,Models, Biological ,Echinococcus ,Host-Parasite Interactions ,Infectious Diseases ,parasitic diseases ,Animals ,Parasitology ,Microtus ,Institut für Biochemie und Biologie - Abstract
The small fox tapeworm (Echinococcus multilocularis) shows a heterogeneous spatial distribution in the intermediate host (Microtus arvalis). To identify the ecological processes responsible for this heterogeneity, we developed a spatially explicit simulation model. The model combines individual-based (foxes, Vulpes vulpes) and grid- based (voles) techniques to simulate the infections in both intermediate and definite host. If host populations are homogeneously mixed, the model reproduces field data for parasite prevalence only for a limited number of parameter combinations. As ecological parameters inevitably vary to a certain degree, we discarded the homogeneous mixing model as insufficient to gain insight into the ecology of the fox tapeworm cycle. We analysed five different model scenarios, each focussing on an ecological process that might be responsible for the heterogeneous spatial distribution of E multilocularis in the intermediate host. Field studies revealed that the prevalence ratio between intermediate and definite host remains stable over a wide range of ecological conditions. Thus, by varying the parameters in simulation experiments, we used the robustness of the agreement between field data and model output as quality criterion for the five scenarios. Only one of the five scenarios was found to reproduce the prevalence ratio over a sufficient range of parameter combinations. In the accentuated scenario most tapeworm eggs die due to bad environmental conditions before they cause infections in the intermediate host. This scenario is supported by the known sensitivity of tapeworm eggs to high temperatures and dry conditions. The identified process is likely to lead to a heterogeneous availability of infective eggs and thus to a clumped distribution of infected intermediate hosts. In conclusion, areas with humid conditions and low temperatures must be pointed out as high risk areas for human exposure to E. multilocularis eggs as well. (C) 2004 on behalf of Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved
- Published
- 2004
49. Is modularity necessary for evolvability?
- Author
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Thomas F. Hansen
- Subjects
Statistics and Probability ,Evolutionary capacitance ,Theoretical computer science ,Property (philosophy) ,Applied Mathematics ,Modularity (biology) ,media_common.quotation_subject ,General Medicine ,Biology ,General Biochemistry, Genetics and Molecular Biology ,Adaptability ,Evolvability ,Pleiotropy (drugs) ,Evolutionary biology ,Modeling and Simulation ,Adaptation ,Selection (genetic algorithm) ,media_common - Abstract
Evolvability is the ability to respond to a selective challenge. This requires the capacity to produce the right kind of variation for selection to act upon. To understand evolvability we therefore need to understand the variational properties of biological organisms. Modularity is a variational property, which has been linked to evolvability. If different characters are able to vary independently, selection will be able to optimize each character separately without interference. But although modularity seems like a good design principle for an evolvable organism, it does not therefore follow that it is the only design that can achieve evolvability. In this essay I analyze the effects of modularity and, more generally, pleiotropy on evolvability. Although, pleiotropy causes interference between the adaptation of different characters, it also increases the variational potential of those characters. The most evolvable genetic architectures may often be those with an intermediate level of integration among characters, and in particular those where pleiotropic effects are variable and able to compensate for each other's constraints.
- Published
- 2003
50. Phase equilibria for complex polymer solutions
- Author
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Anders F Hansen, Georgios M. Kontogeorgis, Thomas Lindvig, Michael Locht Michelsen, and Line L Hestkjær
- Subjects
chemistry.chemical_classification ,Activity coefficient ,Work (thermodynamics) ,General Chemical Engineering ,General Physics and Astronomy ,Thermodynamics ,Polymer ,Miscibility ,Dilution ,Solvent ,chemistry ,Phase (matter) ,Organic chemistry ,Physical and Theoretical Chemistry - Abstract
Many commercially important mixtures contain complex polymers, e.g. paints and coatings. If a good thermodynamic description can be given of these systems it is possible to develop paints, which possess a certain set of properties and at the same time meet some basic requirement as, e.g. regarding the content of organic solvents. This work presents an investigation of the three polymer models Entropic-FV (EFV), UNIFAC-FV (UFV) and GC-Flory (GCF) for their capability of predicting solvent activity coefficients in binary systems containing complex polymers. It is possible to obtain good predictions at finite concentrations and satisfactory predictions at infinite dilution, particularly with the EFV model. The investigation shows that EFV is the most robust and stable of the models, which indicates that it is the most well suited model for further development of methods for predicting the miscibility behavior of paints and related systems.
- Published
- 2002
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