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Endoscopy represents a commonly employed technique for canine enteropathies. Different trials in human intestinal endoscopy have suggested that the introduction of water for luminal distension, in place of air, improves the visualization of the mucosal texture and decreases pain. The aim of the study was to compare water immersion (WI) vs. air insufflation (AI) during duodenoscopy in anesthetized dogs in terms of mucosal visualization and nociception. Twenty-five dogs undergoing duodenoscopy were included. The same image of the descending duodenum was recorded applying WI and AI. Each pair of images was analyzed using morphological skeletonization, an image entropy evaluation, and a subjective blind evaluation by three experienced endoscopists. To evaluate differences in nociception related to the procedure applied, heart rate and arterial blood pressure were measured before, during and after WI/AI. To compare the two methods, a t-test for paired data was applied for the image analysis, Fleiss' Kappa evaluation for the subjective evaluation and a Friedman test for anesthetic parameters. No differences were found between WI and AI using morphological skeletonization and entropy. The subjective evaluation identified the WI images as qualitatively better than the AI images, indicating substantial agreement between the operators. No differences in nociception were found. The results of the study pointed out the absence of changes in pain response between WI and AI, likely due to the sufficient control of nociception by the anesthesia. Based on subjective evaluation, but not confirmed by the image analysis, WI provided better image quality than AI.

Background: Anakinra might improve the prognosis of patients with moderate to severe COVID-19 (ie, patients requiring oxygen supplementation but not yet receiving organ support). We aimed to assess the effect of anakinra treatment on mortality in patients admitted to hospital with COVID-19. Methods: For this systematic review and individual patient-level meta-analysis, a systematic literature search was done on Dec 28, 2020, in Medline (PubMed), Cochrane, medRxiv, bioRxiv, and the ClinicalTrials.gov databases for randomised trials, comparative studies, and observational studies of patients admitted to hospital with COVID-19, comparing administration of anakinra with standard of care, or placebo, or both. The search was repeated on Jan 22, 2021. Individual patient-level data were requested from investigators and corresponding authors of eligible studies; if individual patient-level data were not available, published data were extracted from the original reports. The primary endpoint was mortality after 28 days and the secondary endpoint was safety (eg, the risk of secondary infections). This study is registered on PROSPERO (CRD42020221491). Findings: 209 articles were identified, of which 178 full-text articles fulfilled screening criteria and were assessed. Aggregate data on 1185 patients from nine studies were analysed, and individual patient-level data on 895 patients were provided from six of these studies. Eight studies were observational and one was a randomised controlled trial. Most studies used historical controls. In the individual patient-level meta-analysis, after adjusting for age, comorbidities, baseline ratio of the arterial partial oxygen pressure divided by the fraction of inspired oxygen (PaO2/FiO2), C-reactive protein (CRP) concentrations, and lymphopenia, mortality was significantly lower in patients treated with anakinra (38 [11%] of 342) than in those receiving standard of care with or without placebo (137 [25%] of 553; adjusted odds ratio [OR] 0·32 [95% CI 0·20–0·51]). The mortality benefit was similar across subgroups regardless of comorbidities (ie, diabetes), ferritin concentrations, or the baseline PaO2/FiO2. In a subgroup analysis, anakinra was more effective in lowering mortality in patients with CRP concentrations higher than 100 mg/L (OR 0·28 [95% CI 0·17–0·47]). Anakinra showed a significant survival benefit when given without dexamethasone (OR 0·23 [95% CI 0·12–0·43]), but not with dexamethasone co-administration (0·72 [95% CI 0·37–1·41]). Anakinra was not associated with a significantly increased risk of secondary infections when compared with standard of care (OR 1·35 [95% CI 0·59–3·10]). Interpretation: Anakinra could be a safe, anti-inflammatory treatment option to reduce the mortality risk in patients admitted to hospital with moderate to severe COVID-19 pneumonia, especially in the presence of signs of hyperinflammation such as CRP concentrations higher than 100 mg/L. Funding: Sobi. © 2021 Elsevier Ltd

BackgroundThere is currently no consensual definition of flare in axial spondyloarthritis (axSpA).ObjectivesThe aims of this study were to determine thresholds of variations of BASDAI associated with patient-reported flare and to test performance of ASAS preliminary definitions of flare1.MethodsThis prospective study was proposed to all patients registered on the Spondy+ platform, a secure e-health platform for SpA patients. Every week during one year, patients were invited to connect to the platform to fill a BASDAI questionnaire, a 0-10 pain visual analogic scale and to answer to the following question: “has your disease flared up since last week?”. Variations of BASDAI and pain between connections were assessed and associated to the change of perception of flare. ROC curves were built to assess performances of BASDAI and VAS to identify patient-reported occurrence and resolution of flare. Performance of ASAS preliminary definitions of flare was also assessed.Results99 patients participated to this study for an average duration of 309 ± 148 days. 92% of them reported at least one episode of flare over follow-up. Area under the ROC curve (AUC) was significantly higher for ΔBASDAI than for Δpain, to predict outbreak of flare (0.81 vs 0.77, p=0.02). In contrast, ΔBASDAI and Δpain were comparably accurate to predict flare resolution with no significant difference of AUC (0.78 vs 0.80, p=0.4). Best performance was obtained for an increase of 0.2 points of BASDAI (sensitivity=70%; specificity=79%) and 0.5 of pain VAS to predict outbreak of flare and a decrease of 0.4 points of BASDAI and 0.5 of pain VAS to predict flare resolution (Figure 1). None of the ASAS definitions yielded sensitivity values higher than 37% whereas specificity was higher than 95% for all of them.Figure 1.Sensitivity (red dots) and specificity (blue dots) according to ΔBASDAI (panels A,C) and Δpain (panels B,D) threshold as predictors of outbreak (panels A,B) or resolution (panels C,D) of flare.ConclusionΔBASDAI appeared as a suitable variable to monitor both occurrence and resolution of SpA flare, as reported by patient.References[1]Gossec L et al. Ann Rheum Dis 2016;75:991–6. doi:10.1136/annrheumdis-2015-208593AcknowledgementsThe authors thank MSD France for unrestricted financial support to the SPONDY+ platform and Frédéric Durand-Salmon for giving us the possibility to use SPONDY+, a patient support program developed by BEPATIENT.Disclosure of InterestsNone declared

Population densities of a species measured in different locations are often correlated over time, a phenomenon referred to as synchrony. Synchrony results from dispersal of individuals among locations and spatially correlated environmental variation, among other causes. Synchrony is often measured by a correlation coefficient. However, synchrony can vary with timescale. We demonstrate theoretically and experimentally that the timescale-specificity of environmental correlation affects the overall magnitude and timescale-specificity of synchrony, and that these effects are modified by population dispersal. Our laboratory experiments linked populations of flour beetles by changes in habitat size and dispersal. Linear filter theory, applied to a metapopulation model for the experimental system, predicted the observed timescale-specific effects. The timescales at which environmental covariation occurs can affect the population dynamics of species in fragmented habitats.

Pyogranulomatous inflammation has been extensively described in cats, in particular in cases of feline infectious peritonitis and also associated with Mycobacteria, Actinomyces, Nocardia, Rhodococcus and fungal infections. Idiopathic sterile pyogranulomatous dermatitis has also been described. In this case series we describe the clinical presentation, histopathology and outcome of three cases of feline idiopathic sterile steroid-responsive pyogranuloma with different presentation and different locations of the lesion, but with the common feature of having a mass with no superficial skin involvement.

Background This prospective study evaluated the technical aspects and microbiological consequences of laparoscopic resection with transanal specimen extraction and per ano transcolonic stapler anvil insertion in patients requiring elective operation for previous diverticulitis. Methods Laparoscopic sigmoid colectomy was performed with three ports, and specimen extraction carried out transanally through a complete opening of the rectal stump. A triple-stapled anastomosis restored colonic continuity. Systematic intraoperative bacteriological sampling was performed. Intraoperative data as well as microbiological and postoperative outcomes were evaluated prospectively. Results Sixteen consecutive patients were studied over a 6-month period. All procedures were technically satisfactory, with a mean(s.d.) operating time of 120·9(41·9) min. No conversion or additional access was required. Four of the 16 patients developed complications, but none required intervention. Although polybacterial growth was present in all peritoneal culture samples, no infection-related complications were observed. Two patients had an extended course of perioperative antibiotic cover owing to overt peritoneal cavity contamination during surgery, and in two further patients antibiotics were instituted empirically following the development of postoperative fever alone. Conclusion Transanal specimen extraction in addition to per ano transcolonic stapler anvil insertion allows laparoscopic sigmoid resection to be performed with just three ports. Although intraperitoneal bacterial contamination occurs, this does not appear to translate into infectious morbidity.

Radial and longitudinal strain assessment in the carotid artery wall using speckle tracking

Populations fluctuate because of their internal dynamics, which can be nonlinear and stochastic, and in response to environmental variation. Theory predicts how the colour of environmental stochasticity affects population means, variances and correlations with the environment over time. The theory has not been tested for cycling populations, commonly observed in field systems. We applied noise of different colours to cycling laboratory beetle populations, holding other statistical properties of the noise fixed. Theory was largely validated, but failed to predict observations in sufficient detail. The main period of population cycling was shifted up to 33% by the colour of environmental stochasticity. Noise colour affected population means, variances and dominant periodicities differently for populations that cycled in different ways without noise. Our results show that changes in the colour of climatic variability, partly caused by humans, may affect the main periodicity of cycling populations, possibly impacting industry, pest management and conservation.

Stochasticity alters the nonlinear dynamics of inherently cycling populations. The power spectrum can describe and explain the impacts of stochasticity. We fitted models to short observed time series of flour beetle populations in the frequency domain, then used a well fitting stochastic mechanistic model to generate detailed predictions of population spectra. Some predicted spectral peaks represent periodic phenomena induced or modified by stochasticity and were experimentally confirmed. For one experimental treatment, linearization theory explained that these peaks represent overcompensatory decay of deviations from deterministic oscillation. In another treatment, stochasticity caused frequent directional phase shifting around a cyclic attractor. This directional phase shifting was not explained by linearization theory and modified the periodicity of the system. If field systems exhibit directional phase shifting, then changing the intensity of demographic or environmental noise while holding constant the structure of the noise can change the main frequency of population fluctuations.

A scaling rule of ecological theory, accepted but lacking experimental confirmation, is that the magnitude of fluctuations in population densities due to demographic stochasticity scales inversely with the square root of population numbers. This supposition is based on analyses of models exhibiting exponential growth or stable equilibria. Using two quantitative measures, we extend the scaling rule to situations in which population densities fluctuate due to nonlinear deterministic dynamics. These measures are applied to populations of the flour beetle Tribolium castaneum that display chaotic dynamics in both 20-g and 60-g habitats. Populations cultured in the larger habitat exhibit a clarification of the deterministic dynamics, which follows the inverse square root rule. Lattice effects, a deterministic phenomenon caused by the discrete nature of individuals, can cause deviations from the scaling rule when population numbers are small. The scaling rule is robust to the probability distribution used to model demographic variation among individuals.

The Tribolium (flour beetle) competition experiments conducted by Park have been highly influential in ecology. We have previously shown that the dynamics of single-species Tribolium populations can be well-described by the discrete-time, 3-dimensional larva–pupa–adult (LPA) model. Motivated by Park's experiments, we explore the dynamics of a 6-dimensional “competition LPA model” consisting of two LPA models coupled through cannibalism. The model predicts a double-loop coexistence attractor, as well as an unstable exclusion equilibrium with a 5-dimensional stable manifold that plays an important role in causing one of the species to go extinct in the presence of stochastic perturbations. We also present a stochastic version of the model, using binomial and Poisson distributions to describe the aggregation of demographic events within life stages. A novel “stochastic outcome diagram,” the stochastic counterpart to a bifurcation diagram, summarizes the model-predicted dynamics of uncertainty on the double-l...

Summary 1. In this journal 35 years ago, P. H. Leslie, T. Park and D. B. Mertz reported competitive exclusion data for two Tribolium species. It is less well-known that they also reported ‘difficult to interpret’ coexistence data. We suggest that the species exclusion and the species coexistence are consequences of a stable coexistence two-cycle in the presence of two stable competitive exclusion equilibria. 2. A stage-structured insect population model for two interacting species forecasts that as interspecific interaction is increased there occurs a sequence of dynamic changes (bifurcations) in which the classic Lotka‐Volterra-type scenario with two stable competitive exclusion equilibria is altered abruptly to a novel scenario with three locally stable entities; namely, two competitive exclusion equilibria and a stable coexistence cycle. This scenario is novel in that it predicts the competitive coexistence of two nearly identical species on a single limiting resource and does so under circumstances of increased interspecific competition. This prediction is in contradiction to classical tenets of competition theory.

An important component of the mathematical definition of chaos is sensitivity to initial conditions. Sensitivity to initial conditions is usually measured in a deterministic model by the dominant Lyapunov exponent (LE), with chaos indicated by a positive LE. The sensitivity measure has been extended to stochastic models; however, it is possible for the stochastic Lyapunov exponent (SLE) to be positive when the LE of the underlying deterministic model is negative, and vice versa. This occurs because the LE is a long-term average over the deterministic attractor while the SLE is the long-term average over the stationary probability distribution. The property of sensitivity to initial conditions, uniquely associated with chaotic dynamics in deterministic systems, is widespread in stochastic systems because of time spent near repelling invariant sets (such as unstable equilibria and unstable cycles). Such sensitivity is due to a mechanism fundamentally different from deterministic chaos. Positive SLE's should therefore not be viewed as a hallmark of chaos. We develop examples of ecological population models in which contradictory LE and SLE values lead to confusion about whether or not the population fluctuations are primarily the result of chaotic dynamics. We suggest that “chaos” should retain its deterministic definition in light of the origins and spirit of the topic in ecology. While a stochastic system cannot then strictly be chaotic, chaotic dynamics can be revealed in stochastic systems through the strong influence of underlying deterministic chaotic invariant sets.

Introduction: A novel technique for secure placement of the anvil for mechanical stapled anastomosis in the proximal colon without exteriorization of the bowel is described. Methods: After standard laparoscopic segmental colonic mobilization, a needle-cannula from a percutaneous endoscopic gastrostomy kit is passed under direct endoscopic vision transparietally into the colon at the site intended for anvil placement. A wire passed through the cannula into the colon is then withdrawn endoscopically per ano. The stapler anvil is fixed to the wire and pulled back along the intestine before being positioned by traction through the needle puncture site. After distal specimen transection, a standard stapled anastomosis is performed. Results: The technique is illustrated in 2 patients undergoing laparoscopic sigmoidectomy by either a single port or a multiport procedure with transanal specimen extraction. Conclusion: By positioning the anvil without colon exteriorization, this technique enables pure intraperitoneal colonic anastomoses that may advance natural orifice operating.

We use the concepts of composite maps, basins of attraction, basin switching, and saddle fly-by's to make the ecological hypothesis of the existence of multiple attractors more accessible to experimental scrutiny. Specifically, in a periodically forced insect population growth model we identify multiple attractors, namely, two locally stable 4-cycles. Using the model-predicted basins of attraction, we examine data time series from a Tribolium experiment for evidence of the multiple attractors. We conclude that the multiple attractor hypothesis together with demographic stochasticity accounts for the experimental observations.

Introduction La maladie de Still est responsable classiquement d’une eruption urticarienne fugace vesperale. D’autres manifestations dermatologiques moins typiques sont decrites : pseudo-urticaire fixe et eruption pseudo-dermatomyosite. Nous rapportons un cas d’inflammation periorbitaire symptomatique chez une patiente de 45 ans suivie pour une maladie de Still depuis l’âge de 12 ans, en interruption therapeutique. Observations Apres 32 annees d’evolution d’une maladie de Still, ou arthrite juvenile idiopathique systemique, la patiente etait en remission durable sous perfusions mensuelles de tocilizumab (Roactemra®) et 9 mg/j de prednisone. Apres une pause therapeutique de 3 mois pour une chirurgie digestive compliquee de surinfection locale et 6 semaines apres la reprise du tocilizumab, la malade a presente un œdeme douloureux palpebral periorbital gauche fixe et d’aggravation progressive en 8 semaines. Il n’y avait ni baisse d’acuite visuelle ni trouble oculomoteur ou autre signe neurologique. D’autres symptomes apparaissaient rapidement : une odynophagie, une eruption cutanee maculeuse erythemateuse des avant-bras et des cuisses, une fievre a 38,4 °C, des arthralgies d’horaire inflammatoire des genoux, poignets, coude droit et inter- et metacarpophalangiennes. Biologiquement, la C-reactive proteine etait elevee a 20 mg/L (N Fig. 1 et 2 ). Conclusion La dacryoadenite est une localisation peu frequente de la maladie de Still. Il faut savoir evoquer ce diagnostic devant un oedeme periorbitaire. La particularite de cette atteinte reside dans son caractere fixe, contrastant avec l’eruption cutanee pseudo-urticarienne evanescente accompagnant la fievre vesperale habituellement decrite. Nous rapportons ici le premier cas de dacryoadenite efficacement traite par anakinra.

To document more fully the characteristics of chronic recurrent multifocal osteomyelitis (CRMO) in pediatric patients, to collect data on the outcomes and management of the disease, and to define prognostic factors.One hundred seventy-eight patients were included (123 female patients and 55 male patients), with a mean ± SD age at diagnosis of 10.9 ± 2.9 years. Inclusion criteria were a diagnosis of CRMO, evidence of at least one lesion of osteitis confirmed by imaging, and development of the syndrome before age 18 years.Longitudinal clinical and imaging studies revealed that only 12 of 178 CRMO patients (7%) had unifocal lesions at the last medical visit. We were able to apply the clinical chronic nonbacterial osteomyelitis score to 110 of 178 patients (62%), which indicated that bone biopsy could have been avoided in 27 cases (25%). At the last medical visit, disease was in remission in only 73 of 171 patients (43%) (41% receiving therapy) after a mean ± SD of 47.9 ± 38.9 months; 44 of 171 patients (26%) experienced sequelae. Using cluster analysis, the CRMO cohort was separated into 3 homogeneous phenotypes (severe, mild, and intermediate). Patients with the severe phenotype had the worst prognosis. This group was entirely composed of male patients, most of whom had the multifocal form of CRMO and inflammatory syndrome. Patients with the mild phenotype had the best prognosis. This group was primarily composed of female patients with a unifocal form of CRMO and infrequent clavicle involvement and inflammatory syndrome. Patients with the intermediate phenotype had a good prognosis but greater reliance on treatment. This group primarily included female patients with multifocal lesions and inflammatory syndrome.This is the largest CRMO cohort described in the literature to date. Clinical evolution and imaging investigations confirmed the multifocal pattern of the disease. Three distinct subgroups of CRMO patients were distinguished, with very different prognoses.

We used small perturbations in adult numbers to control large fluctuations in the chaotic demographic dynamics of laboratory populations of the flour beetle Tribolium castaneum. A nonlinear mathematical model was used to identify a sensitive region of phase space where the addition of a few adult insects would result in a dampening of the life stage fluctuations. Three experimental treatments were applied: one in which perturbations were made whenever the populations were inside the sensitive region (“in-box treatment”), another where perturbations were made whenever the populations were outside the sensitive region (“out-box treatment”), and an unperturbed control. The in-box treatment caused a stabilization of insect densities at numbers well below the peak values exhibited by the out-box and control populations. This study demonstrates how small perturbations can be used to influence the chaotic dynamics of an ecological system.

A defining hypothesis of theoretical ecology during the past century has been that population fluctuations might largely be explained by relatively low-dimensional, non- linear ecological interactions, provided such interactions could be correctly identified and modeled. The realization in recent decades that such nonlinear interactions might result in chaos and other exotic dynamic behaviors has been exciting but tantalizing, in that attri- buting the fluctuations of a particular real population to the complex dynamics of a particular mathematical model has proved to be an elusive goal. We experimentally tested a model- predicted sequence of transitions (bifurcations) in the dynamic behavior of a population from stable equilibria to quasiperiodic and periodic cycles to chaos to three-cycles using cultures of the flour beetle Tribolium. The predictions arose from a system of difference equations (the LPA model) describing the nonlinear life-stage interactions, predominantly cannibalism. We built a stochastic version of the model incorporating demographic vari- ability and obtained conditional least-squares estimates for the model parameters. We gen- erated 2000 ''bootstrapped data sets'' with a time-series bootstrap technique, and for each set we reestimated the model parameters. The resulting 2000 bootstrapped parameter vectors were used to obtain confidence intervals for the model parameters and estimated distri- butions of the Liapunov exponents for the deterministic portion (the skeleton) of the model as well as for the full stochastic model. Frequency distributions of estimated dynamic behaviors of the skeleton at each experimental treatment were produced. For one treatment, over 83% of the bootstrapped parameter estimates corresponded to chaotic attractors, and the remainder of the estimates yielded high-period cycles. The low-dimensional skeleton accounted for at least 90% of the variability in the population abundances and accurately described the responses of populations to experimental demographic manipulations, in- cluding treatments for which the predicted dynamic behavior was chaos. Demographic stochasticity described the remaining noise quite well. We conclude that the fluctuations of experimental flour beetle populations are explained largely by known nonlinear forces involving cannibalistic-stage interactions. Claims of dynamic behavior such as periodic cycles or chaos must be accompanied by a consideration of the reliability of the estimated parameters and a realization that the population fluctuations are a blend of deterministic forces and stochastic events.

Chaos has now been documented in a laboratory population. In controlled laboratory experiments, cultures of flour beetles (Tribolium castaneum) undergo bifurcations in their dynamics as demographic parameters are manipulated. These bifurcations, including a specific route to chaos, are predicted by a well-validated deterministic model called the “LPA model”. The LPA model is based on the nonlinear interactions among the life cycle stages of the beetle (larva, pupa and adult). A stochastic version of the model accounts for the deviations of data from the deterministic model and provides the means for parameterization and rigorous statistical validation. The chaotic attractor of the deterministic LPA model and the stationary distribution of the stochastic LPA model describe the experimental data in phase space with striking accuracy. In addition, model-predicted temporal patterns on the attractor are observed in the data. This paper gives a brief account of the interdisciplinary effort that obtained these results.

Mathematical models predict that a population which oscillates in the absence of time-dependent factors can develop multiple attracting final states in the advent of periodic forcing. A periodically-forced, stage-structured mathematical model predicted the transient and asymptotic behaviors of Tribolium (flour beetle) populations cultured in periodic habitats of fluctuating flour volume. Predictions included multiple (2-cycle) attractors, resonance and attenuation phenomena, and saddle influences. Stochasticity, combined with the deterministic effects of an unstable 'saddle cycle' separating the two stable cycles, is used to explain the observed transients and final states of the experimental cultures. In experimental regimes containing multiple attractors, the presence of unstable invariant sets, as well as stochasticity and the nature, location, and size of basins of attraction, are all central to the interpretation of data.

Oscillatory populations may exhibit a phase change in which, for example, a high–low periodic pattern switches to a low–high pattern. We propose that phase shifts correspond to stochastic jumps between basins of attraction in an appropriate phase space which associates the different phases of a periodic cycle with distinct attractors. This mechanism accounts for two-cycle phase shifts and the occurrence of asynchronous replicates in experimental cultures of Tribolium .

Heparin (HE) was injected into the allantoic sac of chick embryo eggs on the 5th day of incubation. After 48 h, a morphometric analysis of angiogenic response and an immunohistochemical investigation of fibronectin (FN) and type IV collagen immunoreactivity in developing vasculature were performed in order to verify whether HE-related choriollantoic membrane (CAM) angiogenic activity was associated with overexpression of FN and/or type IV collagen changes in CAM extracellular matrix. Data to be presented show a close relationship between HE treatment, angiogenic processes, and overexpression of FN, but not of type IV collagen in CAM extracellular matrix. They agree with other studies proving a facilitating role of FN in angiogenic processes.

The chapter reports a wide survey on the synthesis, structure and properties of many zirconium phosphates and phosphonates, with a special attention devoted to the work made in the Laboratory of Inorganic Chemistry of University of Perugia in the last thirty years. Zirconium phosphates and phosphonates with alpha or gamma type layered structure are first reported. In the second part of the chapter the structure of zirconium aminopolyphosphonates with different dimensionality is also discussed.

We describe a research program which covers a spectrum of activities essential to testing nonlinear population theory: from the translation of the biology into the formal language of mathematics, to the analysis of mathematical models, to the development and application of statistical techniques for the analysis of data, to the design and implementation of biological experiments. The statistical analyses, mathematics, and biology are thoroughly integrated. We review several aspects of our current research effort that demonstrate this integration.

Our approach to testing nonlinear population theory is to connect rigorously mathematical models with data by means of statistical methods for nonlinear time series. We begin by deriving a biologically based demographic model. The mathematical analysis identifies boundaries in parameter space where stable equilibria bifurcate to periodic 2-cy- cles and aperiodic motion on invariant loops. The statistical analysis, based on a stochastic version of the demographic model, provides procedures for parameter estimation, hypothesis testing, and model evaluation. Experiments using the flour beetle Tribolium yield the time series data. A three-dimensional map of larval, pupal, and adult numbers forecasts four possible population behaviors: extinction, equilibria, periodicities, and aperiodic motion including chaos. This study documents the nonlinear prediction of periodic 2-cycles in laboratory cultures of Tribolium and represents a new interdisciplinary approach to un- derstanding nonlinear ecological dynamics.

SIMPLE nonlinear models can generate fixed points, periodic cycles and aperiodic oscillations in population abundance without any external environmental variation. Another familiar theoretical result is that shifts in demographic parameters (such as survival or fecundity) can move a population from one of these behaviours to another1–4. Unfortunately, empirical evidence to support these theoretical possibilities is scarce5–15. We report here a joint theoretical and experimental study to test the hypothesis that changes in demographic parameters cause predictable changes in the nature of population fluctuations. Specifically, we developed a simple model describing population growth in the flour beetle Tribolium16. We then predicted, using standard mathematical techniques to analyse the model, that changes in adult mortality would produce substantial shifts in population dynamic behaviour. Finally, by experimentally manipulating the adult mortality rate we observed changes in the dynamics from stable fixed points to periodic cycles to aperiodic oscillations that corresponded to the transitions forecast by the mathematical model.

To assess the current state of the art of transanal specimen extraction in colonic resections.A systematic literature search was conducted including the terms 'transrectal or transanal specimen extraction', 'Natural Orifice Specimen Extraction' and 'laparoscopic colectomy' for the period from 1955 to May 2011. Exclusion criteria were abdomino-perineal resections, pull-through technique, experimental studies and paediatric population.Nineteen studies met the inclusion criteria, representing 154 patients. The overall postoperative complication rate was 10%. The risks of peritoneal contamination and sphincter dysfunction were evaluated by a single study of each.Transanal extraction is a feasible option to minimize incisions in colorectal surgery.

In many stage-structured species, different life stages often occupy separate spatial niches in a heterogeneous environment. Life stages of the giant flour beetle Tribolium brevicornis (Leconte), in particular adults and pupae, occupy different locations in a homogeneous habitat. This unique spatial pattern does not occur in the well-studied stored grain pests T. castaneum (Herbst) and T. confusum (Duval). We propose density dependent dispersal as a causal mechanism for this spatial pattern. We model and explore the spatial dynamics of T. brevicornis with a set of four density dependent integrodifference and difference equations. The spatial model exhibits multiple attractors: a spatially uniform attractor and a patchy attractor with pupae and adults spatially separated. The model attractors are consistent with experimental observations.

Laparoscopic reversal of Hartmann's procedure is technically demanding. We evaluated the technical aspects and outcome of a standardized approach in a single centre and examined the feasibility of including this into training curricula.The procedure entails a laparoscopy for adhesiolysis and identification and mobilization of the rectal stump. Mobilization of the splenic flexure is performed if necessary, and a colorectal anastomosis is fashioned after introduction of the stapler anvil via the colostomy with intra-abdominal positioning and delivery into the proximal colonic segment to be anastomosed. The stoma is excised as the last step in the operation.Forty-two patients underwent the procedure over an 8-year period with either an expert (n=21) or trainee under expert mentorship (n=21) as first operator. Intra-operative data and postoperative outcomes were evaluated by retrospective review of clinical charts and theatre records. There was a 9.5% conversion rate and 0% mortality. One patient suffered a ureteric injury, while postoperative surgical complications occurred in 7 patients (including one clinical anastomotic leakage). The mean operative time was 117 min. There was no significant difference in intra operative technical parameters or postoperative clinical consequences between procedures performed by a trained surgeon or by a trainee under mentorship.Adherence to a standardized operative protocol and expert mentorship allows this technically demanding operation to be associated with low conversion and complication rates. The absence of any difference between procedures performed by a trainee or trained surgeon suggests that the operation can be included in training programmes for laparoscopic surgery.

Simultaneous occurrence of acute myeloid leukaemia with mutated nucleophosmin ( NPM1 ) in the same family

Motivated by the genetic hypothesis that natural selection results in the maximization of the equilibrium population size, we quantified this latter equilibrium for laboratory populations of the flour beetle Tribolium castaneum, using the gamma probability density function. Gamma density functions were fitted to adult numbers for each of the experimental treatments that were started with frequencies of the corn oil sensitive (cos) allele in the range 0–1 at intervals of 0.1. The gamma density function adequately described all observed distributions. However, contrary to theory, statistical comparisons of the fitted distribution indicate that the polymorphic populations did not converge to the same identical distribution and that the polymorphic populations are intermediate in population size to the two homozygous groups. The need for a stochastic theory that combines both population size and genetic selection is discussed.Key words: natural selection, Tribolium, gamma distribution, maximum population size, stationary distribution, stochastic differential equation, stochastic population model.

We explore the persistence of corn oil sensitivity in a population of the flour beetle Tribolium castaneum using evolutionary game methods that model population dynamics and changes in the mean strategy of a population over time. The strategy in an evolutionary game is a trait that affects the fitness of the organisms. Corn oil sensitivity represents such a strategy in the flour beetle. We adapt an existing model of the ecological dynamics of T. castaneum into an evolutionary game framework to explore the persistence of corn oil sensitivity in the population. The equilibrium allele frequencies resulting from the evolutionary game are evolutionarily stable strategies and compare favorably with those obtained from the experimental data.

Summary Invasive fungal infections are usually associated with immunocompromised states About 40–60% of these patients are refractory to standard antifungal therapy We describe the effect of posoconazole in the treatment of a 12 years-old girl with uncontrolled diabetes mellitus with life-threatening cerebral mucor mycosis and a 4 year old girl boy with chronic granulomatous disease presenting with invasive Aspergillus nidulans infection.

A nonlinear demographic model was used to predict the population dynamics of the flour beetle Tribolium under laboratory conditions and to establish the experimental protocol that would reveal chaotic behavior. With the adult mortality rate experimentally set high, the dynamics of animal abundance changed from equilibrium to quasiperiodic cycles to chaos as adult-stage recruitment rates were experimentally manipulated. These transitions in dynamics corresponded to those predicted by the mathematical model. Phase-space graphs of the data together with the deterministic model attractors provide convincing evidence of transitions to chaos.

This chapter summarizes the concepts and models associated with chaos and bifurcations. It reviews the modeling methodology, nonlinear phenomenon, and dynamics of biological populations. Model assessment is important to distinguish between procedures to parameterize (calibrate) a model and those to validate a model. Part of the success of the deterministic LPA model can be attributed to the model's design around the dominant mechanism known to drive the dynamics of the species. Another aspect of the mechanistic modeling approach that is considered is the inclusion of stochasticity. The connection of the deterministic model to real data is accomplished by modeling the expected deviations of data from model predictions in terms of probabilistic assumptions concerning environmental and demographic sources of noise. One conclusion drawn from the studies is that the deterministic LPA model provides a remarkably accurate description of the flour beetle cultures under various laboratory conditions. It made accurate a priori predictions of the long-term dynamics of beetle populations when demographic parameters of the populations are changed by direct manipulation. One of the features of nonlinearity is that responses are not (necessarily) proportional to disturbances; they might be very unexpected and nonintuitive. Animal numbers or densities come from a finite set of discrete numbers called lattice. The LPA model provides an accurate explanation of patterns. The chapter provides insights into nonlinear population dynamics and a modest step toward the hardening of ecological science.

When observation and theory collide, scientists turn to carefully designed experiments for resolution. Their motivation is especially high in the case of biological systems, which are typically far too complex to be grasped by observation and theory alone. The best procedure, as in the rest of science, is first to simplify the system, then to hold it more or less constant while varying the important parameters one or two at a time to see what happens. —Edward O. Wilson (2002)