416 results on '"Nienow, P."'
Search Results
2. Medical Child Welfare Task Force: A Multidisciplinary Approach to Identifying Medical Child Abuse.
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Vega, Sarah, Nienow, Shalon M, Huang, Maria Z, and Stover, Laurie Bernard
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Humans ,Child Abuse ,Child Welfare ,Child ,Physical Injury - Accidents and Adverse Effects ,Pediatric ,Child Abuse and Neglect Research ,Clinical Research ,Behavioral and Social Science ,Health Services ,Childhood Injury ,Violence Research ,7.3 Management and decision making ,Management of diseases and conditions ,Generic health relevance ,Good Health and Well Being ,Medical and Health Sciences ,Psychology and Cognitive Sciences ,Pediatrics - Abstract
Medical child abuse is a complex form of maltreatment with powerful and long-lasting impacts on the overall health of affected children. The complexity of this condition renders it challenging for clinicians to recognize its presence and intervene appropriately. The failure of medical systems to identify and deescalate care in this form of maltreatment can result in grievous patient harm. Although the medical literature provides limited guidance on how to address these multifaceted cases, several studies advocate for a multidisciplinary approach. Following a severe and chronic case of medical child abuse at our institution, deficits in response became clear within our hospital system. In reaction to these gaps, the Medical Child Welfare Task Force was developed to formalize education and multidisciplinary collaboration around medical child abuse. The support of institutional leadership and the involvement of multiple medical disciplines that commonly encounter these patients was vital to the implementation and long-term success of the endeavor. To facilitate case identification, education was provided to clinicians in a variety of forums. Moreover, we leveraged the electronic medical record to streamline our ability to monitor cases of medical child abuse and communicate the concerns and plan of care to other providers, both within and outside of our health system. A postimplementation survey determined that the establishment of a multidisciplinary team increased provider comfort and skill in identifying and managing cases of suspected medical child abuse.
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- 2023
3. Exploitation, Labor and Sex Trafficking of Children and Adolescents: Health Care Needs of Patients.
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Greenbaum, Jordan, Kaplan, Dana, Young, Janine, Haney, Suzanne B, Sirotnak, Andrew P, Asnes, Andrea Gottsegen, Gavril, Amy R, Gilmartin, Amanda Bird Hoffert, Girardet, Rebecca Greenlee, Heavilin, Nancy D, Laskey, Antoinette, Messner, Stephen A, Mohr, Bethany A, Nienow, Shalon Marie, Rosado, Norell, Forkey, Heather, Keefe, Rachael, Keeshin, Brooks, Matjasko, Jennifer, Edward, Heather, Stedt, Elaine, Hurley, Tammy Piazza, Linton, Julie, Gutierrez, Raul, Caballero, Tania, Falusi, Olanrewaju Lanre Omojokun, Giri, Minal, Griffin, Marsha, Ibrahim, Anisa, Mukerjee, Kimberly, Shah, Sural, and Shapiro, Alan
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Health Services and Systems ,Biomedical and Clinical Sciences ,Health Sciences ,Clinical Research ,Pediatric ,Health Services ,Patient Safety ,Pediatric Research Initiative ,8.1 Organisation and delivery of services ,Health and social care services research ,Management of diseases and conditions ,7.1 Individual care needs ,Generic health relevance ,Mental health ,Good Health and Well Being ,Decent Work and Economic Growth ,Peace ,Justice and Strong Institutions ,Pregnancy ,Female ,Child ,Humans ,United States ,Adolescent ,Human Trafficking ,Risk Factors ,Child Advocacy ,Parturition ,Delivery of Health Care ,COUNCIL ON CHILD ABUSE AND NEGLECT ,COUNCIL ON IMMIGRANT CHILD AND FAMILY HEALTH ,Medical and Health Sciences ,Psychology and Cognitive Sciences ,Pediatrics ,Biomedical and clinical sciences ,Health sciences ,Psychology - Abstract
Exploitation and labor and sex trafficking of children and adolescents is a major public health problem in the United States and throughout the world. Significant numbers of US and non-US-born children and adolescents (including unaccompanied immigrant minors) are affected by this growing concern and may experience a range of serious physical and mental health problems associated with human trafficking and exploitation (T/E). Despite these considerations, there is limited information available for health care providers regarding the nature and scope of T/E and how providers may help recognize and protect children and adolescents. Knowledge of risk factors, recruitment practices, possible indicators of T/E, and common medical, mental, and emotional health problems experienced by affected individuals will assist health care providers in recognizing vulnerable children and adolescents and responding appropriately. A trauma-informed, rights-based, culturally sensitive approach helps providers identify and treat patients who have experienced or are at risk for T/E. As health care providers, educators, and leaders in child advocacy and development, pediatricians play an important role in addressing the public health issues faced by children and adolescents who experience exploitation and trafficking. Working across disciplines with professionals in the community, health care providers can offer evidence-based medical screening, treatment, and holistic services to individuals who have experienced T/E and assist vulnerable patients and families in recognizing signs of T/E.
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- 2023
4. Using thermal UAV imagery to model distributed debris thicknesses and sub-debris melt rates on debris-covered glaciers
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Rosie R. Bisset, Peter W. Nienow, Daniel N. Goldberg, Oliver Wigmore, Raúl A. Loayza-Muro, Jemma L. Wadham, Moya L. Macdonald, and Robert G. Bingham
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Debris-covered glaciers ,melt – surface ,remote sensing ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Supraglacial debris cover regulates the melt rates of many glaciers in mountainous regions around the world, thereby modifying the availability and quality of downstream water resources. However, the influence of supraglacial debris is often poorly represented within glaciological models, due to the absence of a technique to provide high-precision, spatially continuous measurements of debris thickness. Here, we use high-resolution UAV-derived thermal imagery, in conjunction with local meteorological data, visible UAV imagery and vertically profiled debris temperature time series, to model the spatially distributed debris thickness across a portion of Llaca Glacier in the Cordillera Blanca of Peru. Based on our results, we simulate daily sub-debris melt rates over a 3-month period during 2019. We demonstrate that, by effectively calibrating the radiometric thermal imagery and accounting for temporal and spatial variations in meteorological variables during UAV surveys, thermal UAV data can be used to more precisely represent the highly heterogeneous patterns of debris thickness and sub-debris melt on debris-covered glaciers. Additionally, our results indicate a mean sub-debris melt rate nearly three times greater than the mean melt rate simulated from satellite-derived debris thicknesses, emphasising the importance of acquiring further high-precision debris thickness data for the purposes of investigating glacier-scale melt processes, calibrating regional melt models and improving the accuracy of runoff predictions.
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- 2023
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5. Minimal Impact of Late‐Season Melt Events on Greenland Ice Sheet Annual Motion
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Ryan N. Ing, Peter W. Nienow, Andrew J. Sole, Andrew J. Tedstone, and Kenneth D. Mankoff
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ice dynamics ,Greenland ,ice sheet ,subglacial hydrology ,Geophysics. Cosmic physics ,QC801-809 - Abstract
Abstract Extreme melt and rainfall events can induce temporary acceleration of Greenland Ice Sheet motion, leading to increased advection of ice to lower elevations where melt rates are higher. In a warmer climate, these events are likely to become more frequent. In September 2022, seasonally unprecedented air temperatures caused multiple melt events over the Greenland Ice Sheet, generating the highest melt rates of the year. The scale and timing of the largest event overwhelmed the subglacial drainage system, enhancing basal sliding and increasing ice velocities by up to ∼240% relative to pre‐event velocities. However, ice motion returned rapidly to pre‐event levels, and the speed‐ups caused a regional increase in annual ice discharge of only ∼2% compared to when the effects of the speed‐ups were excluded. Therefore, although late melt‐season events are forecast to become more frequent and drive significant runoff, their impact on net mass loss via ice discharge is minimal.
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- 2024
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6. Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis).
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Rocha, Daniel G, de Barros Ferraz, Katia Maria Paschoaletto Micchi, Gonçalves, Lucas, Tan, Cedric Kai Wei, Lemos, Frederico G, Ortiz, Carolina, Peres, Carlos A, Negrões, Nuno, Antunes, André Pinassi, Rohe, Fabio, Abrahams, Mark, Zapata-Rios, Galo, Teles, Davi, Oliveira, Tadeu, von Mühlen, Eduardo M, Venticinque, Eduardo, Gräbin, Diogo M, Mosquera B, Diego, Blake, John, Lima, Marcela Guimarães Moreira, Sampaio, Ricardo, Percequillo, Alexandre Reis, Peters, Felipe, Payán, Esteban, Borges, Luiz Henrique Medeiros, Calouro, Armando Muniz, Endo, Whaldener, Pitman, Renata Leite, Haugaasen, Torbjørn, Silva, Diego Afonso, de Melo, Fabiano R, de Moura, André Luis Botelho, Costa, Hugo CM, Lugarini, Camile, de Sousa, Ilnaiara Gonçalves, Nienow, Samuel, Santos, Fernanda, Mendes-Oliveiras, Ana Cristina, Del Toro-Orozco, Wezddy, D'Amico, Ana Rafaela, Albernaz, Ana Luisa, Ravetta, André, do Carmo, Elaine Christina Oliveira, Ramalho, Emiliano, Valsecchi, João, Giordano, Anthony J, Wallace, Robert, Macdonald, David W, and Sollmann, Rahel
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carnivore conservation ,deforestation ,endemic species ,forest fragmentation ,multi-scale analysis ,species distribution - Abstract
The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species.
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- 2020
7. Environmental photochemistry on plants: recent advances and new opportunities for interdisciplinary research
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Sleiman, Mohamad, Nienow, Amanda, and Richard, Claire
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- 2022
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8. Functional Coronary Artery Assessment: a Systematic Literature Review
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Freitas, Samuel A., Nienow, Débora, da Costa, Cristiano A., and Ramos, Gabriel de O.
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- 2022
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9. Modelling the effect of submarine iceberg melting on glacier-adjacent water properties
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B. J. Davison, T. Cowton, A. Sole, F. Cottier, and P. Nienow
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
The rate of ocean-driven retreat of Greenland's tidewater glaciers remains highly uncertain in predictions of future sea level rise, in part due to poorly constrained glacier-adjacent water properties. Icebergs and their meltwater contributions are likely important modifiers of fjord water properties, yet their effect is poorly understood. Here, we use a 3-D ocean circulation model, coupled to a submarine iceberg melt module, to investigate the effect of submarine iceberg melting on glacier-adjacent water properties in a range of idealised settings. Submarine iceberg melting can modify glacier-adjacent water properties in three principal ways: (1) substantial cooling and modest freshening in the upper ∼50 m of the water column; (2) warming of Polar Water at intermediate depths due to iceberg melt-induced upwelling of warm Atlantic Water and; (3) warming of the deeper Atlantic Water layer when vertical temperature gradients through this layer are steep (due to vertical mixing of warm water at depth) but cooling of the Atlantic Water layer when vertical temperature gradients are shallow. The overall effect of iceberg melt is to make glacier-adjacent water properties more uniform with depth. When icebergs extend to, or below, the depth of a sill at the fjord mouth, they can cause cooling throughout the entire water column. All of these effects are more pronounced in fjords with higher iceberg concentrations and deeper iceberg keel depths. These iceberg melt-induced changes to glacier-adjacent water properties will reduce rates of glacier submarine melting near the surface, increase them in the Polar Water layer, and cause typically modest impacts in the Atlantic Water layer. These results characterise the important role of submarine iceberg melting in modifying ice sheet-ocean interaction and highlight the need to improve representations of fjord processes in ice sheet scale models.
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- 2022
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10. Complex multi-decadal ice dynamical change inland of marine-terminating glaciers on the Greenland Ice Sheet
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Joshua J. Williams, Noel Gourmelen, and Peter Nienow
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Arctic glaciology ,atmosphere-ice-ocean interactions ,glacier flow ,ice dynamics ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Greenland's future contribution to sea-level rise is strongly dependent on the extent to which dynamic perturbations, originating at the margin, can drive increased ice flow within the ice-sheet interior. However, reported observations of ice dynamical change at distances >~50 km from the margin have a very low spatial and temporal resolution. Consequently, the likely response of the ice-sheet's interior to future oceanic and atmospheric warming is poorly constrained. Through combining GPS and satellite-image-derived ice velocity measurements, we measure multi-decadal (1993–1997 to 2014–2018) velocity change at 45 inland sites, encompassing all regions of the ice sheet. We observe an almost ubiquitous acceleration inland of tidewater glaciers in west Greenland, consistent with acceleration and retreat at glacier termini, suggesting that terminus perturbations have propagated considerable distances (>100 km) inland. In contrast, outside of Kangerlussuaq, we observe no acceleration inland of tidewater glaciers in east Greenland despite terminus retreat and near-terminus acceleration, and suggest propagation may be limited by the influence of basal topography and ice geometry. This pattern of inland dynamical change indicates that Greenland's future contribution to sea-level will be spatially complex and will depend on the capacity for dynamic changes at individual outlet glacier termini to propagate inland.
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- 2021
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11. Changes in elevation and mass of Arctic glaciers and ice caps, 2010–2017
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Tepes, P., Gourmelen, N., Nienow, P., Tsamados, M., Shepherd, A., and Weissgerber, F.
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- 2021
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12. Quantification of bovine plasma amino acids via liquid chromatography–electrospray ionization-mass spectrometry: Comparison of underivatized and precolumn derivatized methods
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Mateus Z. Toledo, Caleb Nienow, Daniel Luchini, Sebastian I. Arriola Apelo, and Milo C. Wiltbank
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Dairy processing. Dairy products ,SF250.5-275 - Abstract
The objectives of this experiment were to evaluate and compare underivatized (UND) and precolumn derivatized (DER) methods for quantification of bovine plasma AA by isotope dilution ratio via liquid chromatography-electrospray ionization (ESI)-single quadrupole mass spectrometry. Linearity of the mass-to-charge ratio signal and area signal sensitivity of 12C were evaluated for each AA with 5-point standard curves (range: 1.1–500 µM). Plasma from lactating dairy cows was isolated by centrifugation and deproteinized using 1 N perchloric acid with a final concentration of 0.5 N. Deproteinized plasma was filtered and injected into a 50 × 2-mm column (Imtakt) or extracted, derivatized, and injected into a 250 × 3-mm column (EZ:faast, Phenomenex) and analyzed via liquid chromatography-ESI-single quadrupole mass spectrometry. Coefficients of variation and recovery rates were evaluated using 4 replicates of pooled plasma samples spiked with each AA at concentrations of 10, 20, and 50 µM. In addition, a subset of 24 plasma samples was used to directly compare methods using linear regression, correlation coefficient (r), concordance correlation coefficient (CCC), and Bland-Altman plot test. Both methods showed linearity within the dynamic range analyzed for all essential AA (coefficient of determination, R2 ≥ 0.995) and most other AA, although the UND samples had poor linearity (R2 ≤ 0.990) or peak resolution problems for Asp, Gly, Tyr, and Ser. Moreover, area signal sensitivity for 12C AA was greater for DER samples than for UND samples [range: 2.2× (Pro) to 309.5× (Ala)]. Both methods had recovery rates ranging from 85.7 to 119.8.0%, and none differed from 100% except Gln [20 µM (85.7%) and 50 µM (87.6%)] and Val [50 µM (119.8%)] using the UND method. The UND method had a coefficient of variation ranging from 0.9% (Val) to 7.8% (His), whereas for the DER method the range was 2.2% (Glu) to 8.8% (Asp). The highest correlation coefficient (>0.90) and CCC (>0.90) were observed for Arg, Ile, Leu, Met, Thr, Trp, Val, and Gln, with the Bland-Altman plot test showing minimal mean bias for these AA. Lowest values were observed for His (r = 0.46; CCC = 0.45), Lys (r = 0.76; CCC = 0.75), Ala (r = 0.83; CCC = 0.73), and Glu (r = 0.65; CCC = 0.42). The UND method showed linearity, precision, and accurate recovery rates for most AA, with most essential AA having comparable values between the 2 methods. However, the DER method had greater 12C AA area signal sensitivity, linearity, and recovery rates.
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- 2021
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13. Needle to needle robot‐assisted manufacture of cell therapy products
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Jelena Ochs, Mariana P. Hanga, Georgina Shaw, Niamh Duffy, Michael Kulik, Nokilaj Tissin, Daniel Reibert, Ferdinand Biermann, Panagiota Moutsatsou, Shibani Ratnayake, Alvin Nienow, Niels Koenig, Robert Schmitt, Qasim Rafiq, Christopher J. Hewitt, Frank Barry, and J. Mary Murphy
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automation: bioreactors ,cell therapy ,human stem cells ,manufacturing ,Chemical engineering ,TP155-156 ,Biotechnology ,TP248.13-248.65 ,Therapeutics. Pharmacology ,RM1-950 - Abstract
Abstract Advanced therapeutic medicinal products (ATMPs) have emerged as novel therapies for untreatable diseases, generating the need for large volumes of high‐quality, clinically‐compliant GMP cells to replace costly, high‐risk and limited scale manual expansion processes. We present the design of a fully automated, robot‐assisted platform incorporating the use of multiliter stirred tank bioreactors for scalable production of adherent human stem cells. The design addresses a needle‐to‐needle closed process incorporating automated bone marrow collection, cell isolation, expansion, and collection into cryovials for patient delivery. AUTOSTEM, a modular, adaptable, fully closed system ensures no direct operator interaction with biological material; all commands are performed through a graphic interface. Seeding of source material, process monitoring, feeding, sampling, harvesting and cryopreservation are automated within the closed platform, comprising two clean room levels enabling both open and closed processes. A bioprocess based on human MSCs expanded on microcarriers was used for proof of concept. Utilizing equivalent culture parameters, the AUTOSTEM robot‐assisted platform successfully performed cell expansion at the liter scale, generating results comparable to manual production, while maintaining cell quality postprocessing.
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- 2022
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14. Influence of glacier runoff and near-terminus subglacial hydrology on frontal ablation at a large Greenlandic tidewater glacier
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Charlie Bunce, Peter Nienow, Andrew Sole, Tom Cowton, and Benjamin Davison
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Arctic glaciology ,ice/ocean interactions ,iceberg calving ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Frontal ablation from tidewater glaciers is a major component of the total mass loss from the Greenland ice sheet. It remains unclear, however, how changes in atmospheric and oceanic temperatures translate into changes in frontal ablation, in part due to sparse observations at sufficiently high spatial and temporal resolution. We present high-frequency time-lapse imagery (photos every 30 min) of iceberg calving and meltwater plumes at Kangiata Nunaata Sermia (KNS), southwest Greenland, during June–October 2017, alongside satellite-derived ice velocities and modelled subglacial discharge. Early in the melt season, we infer a subglacial hydrological network with multiple outlets that would theoretically distribute discharge and enhance undercutting by submarine melt, an inference supported by our observations of terminus-wide calving during this period. During the melt season, we infer hydraulic evolution to a relatively more channelised subglacial drainage configuration, based on meltwater plume visibility indicating focused emergence of subglacial water; these observations coincide with a reduction in terminus-wide calving and transition to an incised planform terminus geometry. We suggest that temporal variations in subglacial discharge and near-terminus subglacial hydraulic efficiency exert considerable influence on calving and frontal ablation at KNS.
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- 2021
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15. Social Participation in the Brazilian National Biodiversity Monitoring Program Leads to Multiple Socioenvironmental Outcomes
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Monitora, Cecilia Cronemberger, Katia Torres Ribeiro, Rachel Klaczko Acosta, Dárlison Fernandes Carvalho de Andrade, Onildo João Marini-Filho, Laura Shizue Moriga Masuda, Keila Rêgo Mendes, Samuel dos Santos Nienow, Carla Natacha Marcolino Polaz, Marcelo Lima Reis, Ricardo Sampaio, Jumara Marques Souza, and Cristina Farah de Tófoli
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adaptive management ,knowledge management ,governance ,protected area management ,community-based programs ,Science - Abstract
The Brazilian Biodiversity Monitoring Program (Monitora Program) is a long-term large-scale program aimed at monitoring the state of biodiversity and associated ecosystem services in the protected areas (PAs) managed by Instituto Chico Mendes de Conservação da Biodiversidade (ICMBio). Encouraging qualified social participation is one of Monitora Program’s guiding principles. In this case study, we describe how citizen participation occurs in various stages of the Monitora Program, including planning, data collection, interpretation, and discussion of results. Aspects that are crucial for a legitimate and continuous involvement and participation are described. We also illustrate some of the results from the Program and discuss how the program can contribute to Brazil’s achievement of the United Nations (UN) Sustainable Development Goals (SDGs). In 2022, the program was implemented in 113 of the 334 protected areas managed by ICMBio, most of them in the Amazon. The program results are aligned to 12 of the 17 SDGs, influencing changes that move society closer to these goals at the local scale. Data from the Monitora Program can be used to support Brazilian SDG reporting, but this requires further developments. Social participation in Monitora Program has strengthened links between institutions and people of different profiles, enhancing participation in protected area (PA) management and generating multiple local impacts, while producing quality biodiversity information to inform decision-making in conservation.
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- 2023
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16. Development and validation of a set of standard area diagrams to assess severity of gray mold in strawberry fruit
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Filippi, Débora, Nienow, Alexandre Augusto, Chiomento, José Luís Trevizan, dos Santos Trentin, Thomas, Dornelles, Alana Grando, Calvete, Eunice Oliveira, and Huzar-Novakowiski, Jaqueline
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- 2021
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17. Design and development of a new ambr250® bioreactor vessel for improved cell and gene therapy applications
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Rotondi, Marco, Grace, Ned, Betts, John, Bargh, Neil, Costariol, Elena, Zoro, Barney, Hewitt, Christopher J., Nienow, Alvin W., and Rafiq, Qasim A.
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- 2021
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18. Perspective: child abuse in the military
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Rooks, Veronica J., Wood, Jonathan R., Hamele, Mitchell T., Farnsworth, Grant M., and Nienow, Shalon M.
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- 2021
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19. Review article: Earth's ice imbalance
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T. Slater, I. R. Lawrence, I. N. Otosaka, A. Shepherd, N. Gourmelen, L. Jakob, P. Tepes, L. Gilbert, and P. Nienow
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
We combine satellite observations and numerical models to show that Earth lost 28 trillion tonnes of ice between 1994 and 2017. Arctic sea ice (7.6 trillion tonnes), Antarctic ice shelves (6.5 trillion tonnes), mountain glaciers (6.1 trillion tonnes), the Greenland ice sheet (3.8 trillion tonnes), the Antarctic ice sheet (2.5 trillion tonnes), and Southern Ocean sea ice (0.9 trillion tonnes) have all decreased in mass. Just over half (58 %) of the ice loss was from the Northern Hemisphere, and the remainder (42 %) was from the Southern Hemisphere. The rate of ice loss has risen by 57 % since the 1990s – from 0.8 to 1.2 trillion tonnes per year – owing to increased losses from mountain glaciers, Antarctica, Greenland and from Antarctic ice shelves. During the same period, the loss of grounded ice from the Antarctic and Greenland ice sheets and mountain glaciers raised the global sea level by 34.6 ± 3.1 mm. The majority of all ice losses were driven by atmospheric melting (68 % from Arctic sea ice, mountain glaciers ice shelf calving and ice sheet surface mass balance), with the remaining losses (32 % from ice sheet discharge and ice shelf thinning) being driven by oceanic melting. Altogether, these elements of the cryosphere have taken up 3.2 % of the global energy imbalance.
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- 2021
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20. Mycorrhization of strawberry plantlets potentiates the synthesis of phytochemicals during ex vitro acclimatization
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José Luís Trevizan Chiomento, Fabiola Stockmans de Nardi, Débora Filippi, Thomas dos Santos Trentin, Ana Paula Anzolin, Charise Dallazem Bertol, Alexandre Augusto Nienow, and Eunice Oliveira Calvete
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Fragaria x ananassa Duch. ,arbuscular mycorrhiza ,biochar ,biomolecules ,enzymatic activity. ,Agriculture (General) ,S1-972 - Abstract
Ex vitro strawberry plantlets from micropropagation and coinoculated with arbuscular mycorrhizal fungi (AMF) and biochar can provide beneficial health effects. In the present study, we evaluated the effects of different proportions of biochar in the presence and absence of AMF on the production of secondary metabolites in the leaves and roots of strawberry plantlets during ex vitro acclimatization. Additionally, the enzymatic activity of the substrate enriched with AMF and biochar was analyzed. The experiment consisted of the control (absence of the mycorrhizal community) and four biochar proportions (0, 3, 6, and 9% of the volume of the container) coinoculated with AMF. Plantlets produced on substrates enriched with AMF showed higher levels of polyphenols, flavonoids, phenolic acids, and tannins in the tissues analyzed than control plantlets. The combination of AMF and 9% biochar increased the content of total flavonoids in the leaves of strawberry plantlets and increased the activity of phosphatase. The substrate with up to 6% biochar and mycorrhizae showed increased β-glucosidase activity. In conclusion, mycorrhizae are excellent tools to improve the phytochemical quality of strawberry plantlets acclimatized ex vitro. The association between host plants, mycorrhizal symbionts, and bioactivators of these fungi potentiates properties beneficial to health, which can be exploited efficiently in sustainable agriculture.
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- 2022
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21. Fluctuations of a Greenlandic tidewater glacier driven by changes in atmospheric forcing: Observations and modelling of Kangiata Nunaata Sermia, 1859-present
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Lea, JM, Mair, DWF, Nick, FM, Rea, BR, Van As, D, Morlighem, M, Nienow, PW, and Weidick, A
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Meteorology & Atmospheric Sciences ,Oceanography ,Physical Geography and Environmental Geoscience - Abstract
Many tidewater glaciers in Greenland are known to have undergone significant retreat during the last century following their Little Ice Age maxima. Where it is possible to reconstruct glacier change over this period, they provide excellent records for comparison to climate records, as well as calibration/validation for numerical models. These glacier change records therefore allow for tests of numerical models that seek to simulate tidewater glacier behaviour over multi-decadal to centennial timescales. Here we present a detailed record of behaviour from Kangiata Nunaata Sermia (KNS), SW Greenland, between 1859 and 2012, and compare it against available oceanographic and atmospheric temperature data between 1871 and 2012. We also use these records to evaluate the ability of a well-established one-dimensional flow-band model to replicate behaviour for the observation period. The record of terminus change demonstrates that KNS has advanced/retreated in phase with atmosphere and ocean climate anomalies averaged over multi-annual to decadal timescales. Results from an ensemble of model runs demonstrate that observed dynamics can be replicated. Model runs that provide a reasonable match to observations always require a significant atmospheric forcing component, but do not necessarily require an oceanic forcing component. Although the importance of oceanic forcing cannot be discounted, these results demonstrate that changes in atmospheric forcing are likely to be a primary driver of the terminus fluctuations of KNS from 1859 to 2012. We propose that the detail and length of the record presented makes KNS an ideal site for model validation exercises investigating links between climate, calving rates, and tidewater glacier dynamics.
- Published
- 2014
22. Seasonal Variations in Iceberg Freshwater Flux in Sermilik Fjord, Southeast Greenland From Sentinel‐2 Imagery
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A. N. Moyer, D. A. Sutherland, P. W. Nienow, and A. J. Sole
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iceberg freshwater flux ,Greenland Ice Sheet ,Sermilik Fjord ,remote sensing ,Sentinel‐2%22">>Sentinel‐2 ,Geophysics. Cosmic physics ,QC801-809 - Abstract
Abstract Iceberg discharge is estimated to account for up to 50% of the freshwater flux delivered to glacial fjords. The amount, timing, and location of iceberg melting impacts fjord‐water circulation and heat budget, with implications for glacier dynamics, nutrient cycling, and fjord productivity. We use Sentinel‐2 imagery to examine seasonal variations in freshwater flux from open‐water icebergs in Sermilik Fjord, Greenland during summer and fall of 2017–2018. Using iceberg velocities derived from visual‐tracking and changes in total iceberg volume with distance down‐fjord from Helheim Glacier, we estimate maximum average two‐month full‐fjord iceberg‐derived freshwater fluxes of ~1,060 ± 615, 1,270 ± 735, 1,200 ± 700, 3,410 ± 1,975, and 1,150 ± 670 m3/s for May–June, June–July, July–August, August–September, and September–November, respectively. Fluxes decrease with distance down‐fjord, and on average, 86–91% of iceberg volume is lost before reaching the fjord mouth. This method provides a simple, invaluable tool for monitoring seasonal and interannual iceberg freshwater fluxes across a range of Greenlandic fjords.
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- 2019
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23. Spatio-temporal variations in seasonal ice tongue submarine melt rate at a tidewater glacier in southwest Greenland
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A. N. MOYER, P. W. NIENOW, N. GOURMELEN, A. J. SOLE, D. A. SLATER, M. TRUFFER, and M. FAHNESTOCK
- Subjects
glacier calving ,ice/ocean interactions ,remote sensing ,subglacial processes ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Submarine melting of tidewater glaciers is proposed as a trigger for their recent thinning, acceleration and retreat. We estimate spring submarine melt rates (SMRs) of Kangiata Nunaata Sermia in southwest Greenland, from 2012 to 2014, by examining changes in along-fjord freeboard and velocity of the seasonal floating ice tongue. Estimated SMRs vary spatially and temporally near the grounding line, with mean rates of 1.3 ± 0.6, 0.8 ± 0.3 and 1.0 ± 0.4 m d−1 across the tongue in 2012, 2013 and 2014, respectively. Higher melt rates correspond with locations of emerging subglacial plumes and terminus calving activity observed during the melt season using time-lapse camera imagery. Modelling of subglacial flow paths suggests a dynamic system capable of rapid re-routing of subglacial discharge both within and between melt seasons. Our results provide an empirically-derived link between the presence of subglacial discharge plumes and areas of high spring submarine melting and calving along glacier termini.
- Published
- 2019
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- View/download PDF
24. Linear response of east Greenland’s tidewater glaciers to ocean/atmosphere warming
- Author
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Cowton, T. R., Sole, A. J., Nienow, P. W., Slater, D. A., and Christoffersen, P.
- Published
- 2018
25. Heterogeneous and rapid ice loss over the Patagonian Ice Fields revealed by CryoSat-2 swath radar altimetry
- Author
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Foresta, L., Gourmelen, N., Weissgerber, F., Nienow, P., Williams, J.J., Shepherd, A., Drinkwater, M.R., and Plummer, S.
- Published
- 2018
- Full Text
- View/download PDF
26. Twenty-first century glacier slowdown driven by mass loss in High Mountain Asia
- Author
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Dehecq, Amaury, Gourmelen, Noel, Gardner, Alex S., Brun, Fanny, Goldberg, Daniel, Nienow, Peter W., Berthier, Etienne, Vincent, Christian, Wagnon, Patrick, and Trouvé, Emmanuel
- Published
- 2019
- Full Text
- View/download PDF
27. Micorrhizal biotechnology as an alternative to potentialize the strawberry quality
- Author
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Rosiani Castoldi da Costa, Gregori Caglioni Durante, Nicolas dos Santos Trentin, José Luís Trevizan Chiomento, Fabiola Stockmans de Nardi, Alexandre Augusto Nienow, and Eunice Oliveira Calvete
- Subjects
arbuscular mycorrhizal fungi ,total soluble solids ,titratable total acidity ,Fragaria x ananassa Duch. ,Agriculture ,Biology (General) ,QH301-705.5 - Abstract
The need to develop and use biotechnology tools to improve management and nutritional techniques in strawberry cultivation are increasing. Based on this, the objective of this study was to test if the mycorrhizal inoculation changes the agronomic and qualitative performance of strawberry fruits. The strawberry daughters plants used were of the cultivar Camarosa. The study was carried out in an agricultural greenhouse, Horticulture Sector of the Faculty of Agronomy and Veterinary Medicine (FAMV) of UPF, in the city of Passo Fundo, Rio Grande do Sul (RS), Brazil. The experiment was developed and maintained from June to December 2015. The treatments consisted of five inoculum: T1 = no inoculum (control); T2 = Acaulospora morrowiae; T3 = Rhizophagus clarus; T4 = mycorrhizal community; T5 = Claroideoglomus etunicatum. The experimental design was a randomized block with four replicates. Each plot consisted of a bag containing 6 plants spaced 0.15 mx 0.15 m. In the pits of the plants, it was applied, with the aid of syringe and water, about 70 infective propagules of the tested inocula. During the conduction of the experiment the temperature and photosynthetically active radiation (PAR) were monitored in the culture environment. It was evaluated the agronomic and qualitative performance of the fruits and the percentage of mycorrhizal colonization of the plants roots. The data were submitted to analysis of variance and the differences between means were compared by the Tukey test at 5% of probability error. The cultivar Camarosa produced more fruits in October. In September, the month before the one with the best agronomic performance, the mean temperature was 17.7 ºC. The mean PAR recorded in the growing environment was low in relation to crop requirements, throughout the growing period. Fruits produced by plants inoculated with A. morrowiae presented higher values of TSS/TTA ratio in September and October. The percentage of mycorrhizal colonization varied from 26.2% for A. morrowiae to 46.2% for R. clarus. The inoculation of arbuscular mycorrhizal fungi does not alter the production of strawberry fruits. However, when the plants are inoculated with A. morrowiae there is an improvement in the fruit flavor.
- Published
- 2020
28. Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)
- Author
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Daniel G. Rocha, Katia Maria Paschoaletto Micchi de Barros Ferraz, Lucas Gonçalves, Cedric Kai Wei Tan, Frederico G. Lemos, Carolina Ortiz, Carlos A. Peres, Nuno Negrões, André Pinassi Antunes, Fabio Rohe, Mark Abrahams, Galo Zapata-Rios, Davi Teles, Tadeu Oliveira, Eduardo M. von Mühlen, Eduardo Venticinque, Diogo M. Gräbin, Diego Mosquera B., John Blake, Marcela Guimarães Moreira Lima, Ricardo Sampaio, Alexandre Reis Percequillo, Felipe Peters, Esteban Payán, Luiz Henrique Medeiros Borges, Armando Muniz Calouro, Whaldener Endo, Renata Leite Pitman, Torbjørn Haugaasen, Diego Afonso Silva, Fabiano R. de Melo, André Luis Botelho de Moura, Hugo C. M. Costa, Camile Lugarini, Ilnaiara Gonçalves de Sousa, Samuel Nienow, Fernanda Santos, Ana Cristina Mendes-Oliveiras, Wezddy Del Toro-Orozco, Ana Rafaela D'Amico, Ana Luisa Albernaz, André Ravetta, Elaine Christina Oliveira do Carmo, Emiliano Ramalho, João Valsecchi, Anthony J. Giordano, Robert Wallace, David W. Macdonald, and Rahel Sollmann
- Subjects
carnivore conservation ,deforestation ,endemic species ,forest fragmentation ,multi-scale analysis ,species distribution ,Science - Abstract
The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species.
- Published
- 2020
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- View/download PDF
29. The Structural Glaciology of a Temperate Valley Glacier: Haut Glacier d'Arolla, Valais, Switzerland
- Author
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Hambrey, M. J., Nienow, P., and Mair, D.
- Published
- 2005
30. Ice front change of marine-terminating outlet glaciers in northwest and southeast Greenland during the 21st century
- Author
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CHARLIE BUNCE, J. RACHEL CARR, PETER W. NIENOW, NEIL ROSS, and REBECCA KILLICK
- Subjects
arctic glaciology ,glacier fluctuations ,glacier mapping ,remote sensing ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
The increasingly negative mass balance of the Greenland ice sheet (GrIS) over the last ~25 years has been associated with enhanced surface melt and increased ice loss from marine-terminating outlet glaciers. Accelerated retreat during 2000–2010 was concentrated in the southeast and northwest sectors of the ice sheet; however, there was considerable spatial and temporal variability in the timing and magnitude of retreat both within and between these regions. This behaviour has yet to be quantified and compared for all glaciers in both regions. Furthermore, it is unclear whether retreat has continued after 2010 in the northwest, and whether the documented slowdown in the southeast post-2005 has been sustained. Here, we compare spatial and temporal patterns of frontal change in the northwest and southeast GrIS, for the period 2000–2015. Our results show near-ubiquitous retreat of outlet glaciers across both regions for the study period; however, the timing and magnitude of inter-annual frontal position change is largely asynchronous. We also find that since 2010, there is continued terminus retreat in the northwest, which contrasts with considerable inter-annual variability in the southeast. Analysis of the role of glacier-specific factors demonstrates that fjord and bed geometry are important controls on the timing and magnitude of glacier retreat.
- Published
- 2018
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- View/download PDF
31. Dynamic response of the Greenland ice sheet to recent cooling
- Author
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Williams, Joshua J., Gourmelen, Noel, and Nienow, Peter
- Published
- 2020
- Full Text
- View/download PDF
32. A Controlled Trial of Adaptive Disclosure–Enhanced to Improve Functioning and Treat Posttraumatic Stress Disorder.
- Author
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Litz, Brett T., Yeterian, Julie, Berke, Danielle, Lang, Ariel J., Gray, Matt J., Nienow, Tasha, Frankfurt, Sheila, Harris, Jeanette Irene, Maguen, Shira, and Rusowicz-Orazem, Luke
- Subjects
POST-traumatic stress disorder ,REINTEGRATION of veterans ,EVIDENCE-based psychotherapy ,SYMPTOM burden ,PSYCHOSOCIAL functioning ,HARM (Ethics) - Abstract
Objective: This is a randomized controlled trial (NCT03056157) of an enhanced adaptive disclosure (AD) psychotherapy compared to present-centered therapy (PCT; each 12 sessions) in 174 veterans with posttraumatic stress disorder (PTSD) related to traumatic loss (TL) and moral injury (MI). AD employs different strategies for different trauma types. AD-Enhanced (AD-E) uses letter writing (e.g., to the deceased), loving-kindness meditation, and bolstered homework to facilitate improved functioning to repair TL and MI-related trauma. Method: The primary outcomes were the Sheehan Disability Scale (SDS), evaluated at baseline, throughout treatment, and at 3- and 6-month follow-ups (Brief Inventory of Psychosocial Functioning was also administered), the Clinician-Administered PTSD Scale (CAPS-5), the Dimensions of Anger Reactions, the Revised Conflict Tactics Scale, and the Quick Drinking Screen. Results: There were statistically significant between-group differences on two outcomes: The intent-to-treat (ITT) mixed-model analysis of SDS scores indicated greater improvement from baseline to posttreatment in the AD-E group (d = 2.97) compared to the PCT group, d = 1.86; −2.36, 95% CI [−3.92, −0.77], t(1,510) = −2.92, p <.001, d = 0.15. Twenty-one percent more AD-E cases made clinically significant changes on the SDS than PCT cases. From baseline to posttreatment, AD-E was also more efficacious on the CAPS-5 (d = 0.39). These differential effects did not persist at follow-up intervals. Conclusion: This was the first psychotherapy of veterans with TL/MI-related PTSD to show superiority relative to PCT with respect to functioning and PTSD, although the differential effect sizes were small to medium and not maintained at follow-up. What is the public health significance of this article?: Warzone-related posttraumatic stress disorder (PTSD) is a highly multifarious clinical problem, partly because combat trauma can entail extensive traumatic loss and moral injury, either from personal transgressive acts or bearing witness to or being victimized by others' transgressions. Adaptive disclosure (AD) is an evidence-based psychotherapy that was designed to help service members and veterans with war-related PTSD. We applied lessons learned from previous research on AD and enhanced AD to better help war veterans with loss- and moral-injury-related PTSD. We compared the enhanced AD (AD-E) with present-centered therapy (PCT) in a clinical trial of 174 veterans with PTSD. We found AD-E to be superior to PCT with respect to helping veterans function better and in terms of reducing PTSD symptom burden. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
33. Application of a Machine Learning Algorithm in Prediction of Abusive Head Trauma in Children.
- Author
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Jadhav, Priyanka, Sears, Timothy, Floan, Gretchen, Joskowitz, Katie, Nienow, Shalon, Cruz, Sheena, David, Maya, de Cos, Víctor, Choi, Pam, and Ignacio, Romeo C.
- Abstract
We explored the application of a machine learning algorithm for the timely detection of potential abusive head trauma (AHT) using the first free-text note of an encounter and demographic information. First free-text physician notes and demographic information were collected for children under 5 years of age at a Level 1 Trauma Center. The control group, which included patients with head/neck injury, was compared to those with AHT diagnosed by the Child Protective Team. Differential scores accounted for words overrepresented in AHT patient vs. control notes. Sentiment scores were reflective of note positivity/negativity and subjectivity scores accounted for note subjectivity/objectivity. The composite scores reflected the patient's differential score modified by the subjectivity score. Composite, sentiment, and subjectivity scores combined with demographic information trained a Random Forest (RF) machine learning algorithm to predict AHT. Final composite scores with demographic information were highly associated with AHT in a test dataset. The control group included 587 patients and the test group included 193 patients. Combining composite scores with demographic information into the RF model improved AHT classification area under the curve (AUC) from 0.68 to 0.78, with an overall accuracy of 84%. Feature importance analysis of our RF model revealed that composite score, sentiment, age, and subjectivity were the most impactful predictors of AHT. The sentiment was not significantly different between control and AHT notes (p = 0.87), while subjectivity trended higher for AHT notes (p = 0.081). We conclude that a machine learning algorithm can recognize patterns within free-text notes and demographic information that aid in AHT detection in children. III. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
34. Thalassiosira mala (Bacillariophyta), a potentially harmful, marine diatom from Chilka Lake and other coastal localities of Odisha, India: Nomenclature, frustule morphology and global biogeography
- Author
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Prasad, Akshinthala K S K, Nienow, James A, and Lochner, Eric
- Published
- 2018
- Full Text
- View/download PDF
35. Spatially distributed runoff at the grounding line of a large Greenlandic tidewater glacier inferred from plume modelling
- Author
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DONALD SLATER, PETER NIENOW, ANDREW SOLE, TOM COWTON, RUTH MOTTRAM, PETER LANGEN, and DOUGLAS MAIR
- Subjects
glacier hydrology ,ice/ocean interactions ,subglacial processes ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Understanding the drivers of recent change at Greenlandic tidewater glaciers is of great importance if we are to predict how these glaciers will respond to climatic warming. A poorly constrained component of tidewater glacier processes is the near-terminus subglacial hydrology. Here we present a novel method for constraining near-terminus subglacial hydrology with application to marine-terminating Kangiata Nunata Sermia in South-west Greenland. By simulating proglacial plume dynamics using buoyant plume theory and a general circulation model, we assess the critical subglacial discharge, if delivered through a single compact channel, required to generate a plume that reaches the fjord surface. We then compare catchment runoff to a time series of plume visibility acquired from a time-lapse camera. We identify extended periods throughout the 2009 melt season where catchment runoff significantly exceeds the discharge required for a plume to reach the fjord surface, yet we observe no plume. We attribute these observations to spatial spreading of runoff across the grounding line. Persistent distributed drainage near the terminus would lead to more spatially homogeneous submarine melting and may promote more rapid basal sliding during warmer summers, potentially providing a mechanism independent of ocean forcing for increases in atmospheric temperature to drive tidewater glacier acceleration.
- Published
- 2017
- Full Text
- View/download PDF
36. Ice sheets as a missing source of silica to the polar oceans
- Author
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Jon R. Hawkings, Jemma L. Wadham, Liane G. Benning, Katharine R. Hendry, Martyn Tranter, Andrew Tedstone, Peter Nienow, and Rob Raiswell
- Subjects
Science - Abstract
Glacial runoff often has relatively low dissolved silica concentrations and therefore ice sheets have been thought insignificant in the global silicon cycle. Here, the authors show that ice sheets likely play an important role in the production and export of dissolved and dissolvable amorphous silica downstream.
- Published
- 2017
- Full Text
- View/download PDF
37. Peroxidase activity and initial growth of ‘Barbosa’ peach on clonal rootstocks
- Author
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Chirlene Márcia Oldoni, Alexandre Augusto Nienow, Jurema Schons, and Newton Alex Mayer
- Subjects
Prunus persica (L.) Batsch ,graft ,graft compatibility ,Plant culture ,SB1-1110 - Abstract
Abstract In the peach nursery trees production, the use of rootstocks with unknown genetic identity obtained from peach seeds in the canning industry is frequent. The hypothesis tested was that there are rootstocks that express greater graft compatibility, enabling greater survival and growth, and that peroxidase activity can be used as indication of graft incompatibility. The aim of this study was to evaluate the survival and the peroxidase activity efficiency in identifying graft incompatibility and the trunk diameter growth of ‘Barbosa’ peach grafted onto 18 Prunus clonal rootstocks, propagated by herbaceous cuttings, compared to own-rooted scion trees. The experimental design was three randomized blocks, with one tree per plot. The first three vegetative cycles of trees conducted in double Y (5.0m x 2.0m) without irrigation were evaluated. The highest trunk diameter growth was provided by ‘Okinawa’, ‘Tsukuba-1’, ‘Tsukuba-2’, Mexico F1 and ‘Flordaguard’ rootstocks, without differing from own-rooted ‘Barbosa’ peach. Peroxidase activity differs by rootstock effect at the beginning of the dormancy period, and is higher than in vegetative growth, especially in interspecific graft combinations. Peroxidase activity is a biochemical indicator of stress, but should not be used alone and generalized to characterize graft incompatibility.
- Published
- 2019
- Full Text
- View/download PDF
38. Temporal Switching between Englacial and Subglacial Drainage Pathways: Dye Tracer Evidence from the Haut Glacier d'Arolla, Switzerland
- Author
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Nienow, P., Sharp, M., and Willis, I.
- Published
- 1996
- Full Text
- View/download PDF
39. Weathering Dynamics Under Contrasting Greenland Ice Sheet Catchments
- Author
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Alejandra Urra, Jemma Wadham, Jon R. Hawkings, Jon Telling, Jade E. Hatton, Jacob C. Yde, Bent Hasholt, Dirk van As, Maya P. Bhatia, and Peter Nienow
- Subjects
Greenland ,ice sheet ,glaciers ,solute fluxes ,cations ,silica ,Science - Abstract
Chemical weathering dynamics in Greenland Ice Sheet (GrIS) catchments are largely unknown, due to a scarcity of field data. This paper presents the most comprehensive study to date of chemical weathering rates from four GrIS catchments of contrasting size. Cationic denudation rates varied greatly between catchments studied (2.6–37.6 tons km–2 a–1, world mean = 11.9 tons km–2 a–1), but were of the same order of magnitude to the world non-glacial riverine mean, and are greater than those documented in some major temperate rivers catchments (e.g., Mississippi (1.3 tons km–2 a–1) and Nile (0.4 tons km–2 a–1) rivers). These high chemical denudation rates indicate that the GrIS is a potential source of solute to downstream environments. Dissolved silica yields, indicative of silicate weathering rates, also varied by an order of magnitude, with upper values similar to the world mean (0.2–3.8 tons km–2 a–1, world mean = 3.53 tons km–2 a–1). Elevated chemical weathering rates in GrIS catchments are strongly influenced by the specific discharge, which drives flushing of the subglacial environment and physical erosion of the ice sheet bed. The direct relationship between specific discharge and chemical denudation rates supports the hypothesis that GrIS chemical weathering rates and solute fluxes are likely to increase with enhanced melt rates in a warming climate.
- Published
- 2019
- Full Text
- View/download PDF
40. The Influence of Hydrology on the Dynamics of Land-Terminating Sectors of the Greenland Ice Sheet
- Author
-
Benjamin Joseph Davison, Andrew John Sole, Stephen John Livingstone, Tom R. Cowton, and Peter William Nienow
- Subjects
subglacial hydrology ,ice dynamics ,land-terminating ,supraglacial lakes ,Greenland Ice Sheet ,glaciers ,Science - Abstract
Coupling between runoff, hydrology, basal motion, and mass loss (“hydrology-dynamics”) is a critical component of the Greenland Ice Sheet system. Despite considerable research effort, the mechanisms by which runoff influences ice dynamics and the net long-term (decadal and longer) dynamical effect of variations in the timing and magnitude of runoff delivery to the bed remain a subject of debate. We synthesise key research into land-terminating ice sheet hydrology-dynamics, in order to reconcile several apparent contradictions that have recently arisen as understanding of the topic has developed. We suggest that meltwater interaction with subglacial channels, cavities, and deforming subglacial sediment modulates ice flow variability. Increasing surface runoff supply to the bed induces cavity expansion and sediment deformation, leading to early-melt season ice flow acceleration. In the ablation area, drainage of water at times of low runoff from high-pressure subglacial environments toward more efficient drainage pathways is thought to result in reductions in water pressure, ice-bed separation and sediment deformation, causing net slow-down on annual to decadal time-scales (ice flow self-regulation), despite increasing surface melt. Further inland, thicker ice, small surface gradients and reduced runoff suppress efficient drainage development, and a small net increase in both summer and winter ice flow is observed. Predicting ice motion across land-terminating sectors of the ice sheet over the twenty-first century is confounded by inadequate understanding of the processes and feedbacks between runoff and subglacial motion. However, if runoff supply increases, we suggest that ice flow in marginal regions will continue to decrease on annual and longer timescales, principally due to (i) increasing drainage system efficiency in marginal areas, (ii) progressive depression of basal water pressure, and (iii) thinning-induced lowering of driving stresses. At higher elevations, we suggest that minor year-on-year ice flow acceleration will continue and extend further into the interior where self-regulation mechanisms cannot operate and if surface-to-bed meltwater connections form. Based on current understanding, we expect that ice flow deceleration due to the seasonal development of efficient drainage beneath the land-terminating margins of the Greenland Ice Sheet will continue to regulate its future mass loss.
- Published
- 2019
- Full Text
- View/download PDF
41. Controls on the transport of oceanic heat to Kangerdlugssuaq Glacier, East Greenland
- Author
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TOM COWTON, ANDREW SOLE, PETER NIENOW, DONALD SLATER, DAVID WILTON, and EDWARD HANNA
- Subjects
arctic glaciology ,calving ,glacier discharge ,ice/ocean interactions ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
Greenland's marine-terminating glaciers may be sensitive to oceanic heat, but the fjord processes controlling delivery of this heat to glacier termini remain poorly constrained. Here we use a three-dimensional numerical model of Kangerdlugssuaq Fjord, East Greenland, to examine controls on fjord/shelf exchange. We find that shelf-forced intermediary circulation can replace up to ~25% of the fjord volume with shelf waters within 10 d, while buoyancy-driven circulation (forced by subglacial runoff from marine-terminating glaciers) exchanges ~10% of the fjord volume over a 10 d period under typical summer conditions. However, while the intermediary circulation generates higher exchange rates between the fjord and shelf, the buoyancy-driven circulation is consistent over time hence more efficient at transporting water along the full length of the fjord. We thus find that buoyancy-driven circulation is the primary conveyor of oceanic heat to glaciers during the melt season. Intermediary circulation will however dominate during winter unless there is sufficient input of fresh water from subglacial melting. Our findings suggest that increasing shelf water temperatures and stronger buoyancy-driven circulation caused the heat available for melting at Kangerdlugssuaq Glacier to increase by ~50% between 1993–2001 and 2002–11, broadly coincident with the onset of rapid retreat at this glacier.
- Published
- 2016
- Full Text
- View/download PDF
42. Sources, cycling and export of nitrogen on the Greenland Ice Sheet
- Author
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J. L. Wadham, J. Hawkings, J. Telling, D. Chandler, J. Alcock, E. O'Donnell, P. Kaur, E. Bagshaw, M. Tranter, A. Tedstone, and P. Nienow
- Subjects
Ecology ,QH540-549.5 ,Life ,QH501-531 ,Geology ,QE1-996.5 - Abstract
Fjord and continental shelf environments in the polar regions are host to some of the planet's most productive ecosystems and support economically important fisheries. Their productivity, however, is often critically dependent upon nutrient supply from upstream terrestrial environments delivered via river systems. In glacially fed coastal ecosystems, riverine nutrients are largely sourced from melting snow and ice. The largest and most extensive glacially fed coastal ecosystem in the Arctic is that bordering the Greenland Ice Sheet. The future primary productivity of this ecosystem, however, is uncertain. A potential increase in primary productivity driven by reduced sea ice extent and associated increased light levels may be curtailed by insufficient nutrient supply, and specifically nitrogen. Research on small valley glaciers indicates that glaciers are important sources of nitrogen to downstream environments. However, no data exist from ice sheet systems such as Greenland. Time series of nitrogen concentrations in runoff are documented from a large Greenland glacier, demonstrating seasonally elevated fluxes to the ocean. Fluxes are highest in mid-summer, when nitrogen limitation is commonly reported in coastal waters. It is estimated that approximately half of the glacially exported nitrogen is sourced from microbial activity within glacial sediments at the surface and bed of the ice sheet, doubling nitrogen fluxes in runoff. Summer dissolved inorganic nitrogen fluxes from the Greenland Ice Sheet (30–40 Gg) are a similar order of magnitude to those from a large Arctic river (Holmes et al., 2012). Nitrogen yields from the ice sheet (236 kg TDN km−2 a−1), however, are approximately double those from Arctic riverine catchments. We assert that this ice sheet nitrogen subsidy to Arctic coastal ecosystems may be important for understanding coastal biodiversity, productivity and fisheries and should be considered in future biogeochemical modelling studies of coastal marine productivity in the Arctic regions.
- Published
- 2016
- Full Text
- View/download PDF
43. Variability in ice motion at a land-terminating Greenlandic outlet glacier: the role of channelized and distributed drainage systems
- Author
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TOM COWTON, PETER NIENOW, ANDREW SOLE, IAN BARTHOLOMEW, and DOUGLAS MAIR
- Subjects
glacier hydrology ,ice dynamics ,subglacial processes ,Environmental sciences ,GE1-350 ,Meteorology. Climatology ,QC851-999 - Abstract
We use a combination of field observations and hydrological modelling to examine the mechanisms through which variability in meltwater input affects ice motion at a land-terminating Greenlandic outlet glacier. We find a close agreement between horizontal ice velocity, vertical ice velocity and modelled subglacial water pressure over the course of a melt season. On this basis, we argue that variation in horizontal and vertical ice velocity primarily reflects the displacement of basal ice during periods of cavity expansion and contraction, a process itself driven by fluctuations in basal water pressure originating in subglacial channels. This process is not captured by traditional sliding laws linking water pressure and basal velocity, which may hinder the simulation of realistic diurnal to seasonal variability in ice velocity in coupled models of glacial hydrology and dynamics.
- Published
- 2016
- Full Text
- View/download PDF
44. DIVERSIDADE FÍSICO-QUÍMICA DOS FRUTOS DE JABUTICABEIRAS EM UM SÍTIO DE OCORRÊNCIA NATURAL
- Author
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LUCAS ZERBIELLI, ALEXANDRE AUGUSTO NIENOW, LUANA DALACORTE, RONALDO JACOBS, and TÁLISSON DARONCH
- Subjects
divergência genética ,frutas nativas ,jabuticaba ,Plinia cauliflora ,Plant culture ,SB1-1110 - Abstract
RESUMO Conhecer a variabilidade genética de uma espécie, manifestada em caracteres morfológicos e agronômicos, é fundamental para orientar sua conservação e manejo, e subsidiar programas de melhoramento. O objetivo deste estudo foi avaliar a diversidade físico-química dos frutos de jabuticabeiras (Plinia cauliflora) em um sítio de ocorrência natural, no município de Passo Fundo-RS. Em uma população de aproximadamente 300 jabuticabeiras, coletaram-se frutos de 40 genótipos para a avaliação de doze caracteres. Os dados foram submetidos à análise descritiva, de correlação e multivariada. Utilizou-se do método de agrupamento UPGMA, a partir da distância euclidiana média. Os genótipos G18 e G35 destacaram-se pelas características relacionadas com o tamanho e o sabor dos frutos, e também por apresentarem alta divergência genética com os demais genótipos. A relação SST/ATT foi o caractere que mais contribuiu para a divergência genética (41,56%), seguido pela porcentagem de polpa (25,76%) e de casca (23,24%). Houve a formação de seis grupos de genótipos similares. Verificou-se, portanto, que jabuticabeiras nativas de um mesmo sítio de ocorrência apresentam frutos com características físico-químicas variáveis, revelando a existência de genótipos com caracteres de interesse no melhoramento da espécie.
- Published
- 2016
- Full Text
- View/download PDF
45. Recent Advances in Our Understanding of the Role of Meltwater in the Greenland Ice Sheet System
- Author
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Nienow, P. W., Sole, A. J., Slater, D. A., and Cowton, T. R.
- Published
- 2017
- Full Text
- View/download PDF
46. Time of treatment with IBA in Olive cultivars rooting
- Author
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Verena Heloise Hanel Inocente, Alexandre Augusto Nienow, and Laura Tre
- Subjects
Olea europaea L. ,propagação vegetativa ,estaquia ,ácido indolbutírico ,Plant culture ,SB1-1110 - Abstract
Abstract Phytoregulators such as indole butyric acid (IBA), have been used in the process of olive tree rooting in the form of concetrated hydroalcoholic solutions. The objective of this present study was to evaluate the efficiency of a low concentration of IBA (300 mg L-1), diluted in a solution of only 10% of alcohol 70 oGL, in the rooting of four olive tree cultivars (Arbequina, Arbosana, Frantoio and Koroneiki), treated in different times of base immersion (0, 1, 2, 4 and 8 hours). The rooting was carried out in november 2015, in greenhouse with an irrigation system type intermittent mist chamber. The cuttings standard were 12 cm length and two pairs of leaves, planted in plastic tubings, containing carbonized rice husk as substrate. The experimental design was achieved in randomized blocks, in factorial arrangement of 4 x 5, with four replications and 12 cuttings per plot. After 70 days of rooting it was verified that the increase of treatment time affected the leaf retention, survival and rooting negativelly. Leaf retention presented positive relationship with survival and rooting. The treatment for one hour in a solution of IBA was effective in the cuttings rooting stimulus of cultivar Arbosana (66,7%). Cultivars Koroneiki and Arbequina presented low or null rooting whether or not the IBA was used.
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- 2018
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47. Changes in the firn structure of the western Greenland Ice Sheet caused by recent warming
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S. de la Peña, I. M. Howat, P. W. Nienow, M. R. van den Broeke, E. Mosley-Thompson, S. F. Price, D. Mair, B. Noël, and A. J. Sole
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
Atmospheric warming over the Greenland Ice Sheet during the last 2 decades has increased the amount of surface meltwater production, resulting in the migration of melt and percolation regimes to higher altitudes and an increase in the amount of ice content from refrozen meltwater found in the firn above the superimposed ice zone. Here we present field and airborne radar observations of buried ice layers within the near-surface (0–20 m) firn in western Greenland, obtained from campaigns between 1998 and 2014. We find a sharp increase in firn-ice content in the form of thick widespread layers in the percolation zone, which decreases the capacity of the firn to store meltwater. The estimated total annual ice content retained in the near-surface firn in areas with positive surface mass balance west of the ice divide in Greenland reached a maximum of 74 ± 25 Gt in 2012, compared to the 1958–1999 average of 13 ± 2 Gt, while the percolation zone area more than doubled between 2003 and 2012. Increased melt and column densification resulted in surface lowering averaging −0.80 ± 0.39 m yr−1 between 1800 and 2800 m in the accumulation zone of western Greenland. Since 2007, modeled annual melt and refreezing rates in the percolation zone at elevations below 2100 m surpass the annual snowfall from the previous year, implying that mass gain in the region is retained after melt in the form of refrozen meltwater. If current melt trends over high elevation regions continue, subsequent changes in firn structure will have implications for the hydrology of the ice sheet and related abrupt seasonal densification could become increasingly significant for altimetry-derived ice sheet mass balance estimates.
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- 2015
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48. Modelling the transfer of supraglacial meltwater to the bed of Leverett Glacier, Southwest Greenland
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C. C. Clason, D. W. F. Mair, P. W. Nienow, I. D. Bartholomew, A. Sole, S. Palmer, and W. Schwanghart
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Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
Meltwater delivered to the bed of the Greenland Ice Sheet is a driver of variable ice-motion through changes in effective pressure and enhanced basal lubrication. Ice surface velocities have been shown to respond rapidly both to meltwater production at the surface and to drainage of supraglacial lakes, suggesting efficient transfer of meltwater from the supraglacial to subglacial hydrological systems. Although considerable effort is currently being directed towards improved modelling of the controlling surface and basal processes, modelling the temporal and spatial evolution of the transfer of melt to the bed has received less attention. Here we present the results of spatially distributed modelling for prediction of moulins and lake drainages on the Leverett Glacier in Southwest Greenland. The model is run for the 2009 and 2010 ablation seasons, and for future increased melt scenarios. The temporal pattern of modelled lake drainages are qualitatively comparable with those documented from analyses of repeat satellite imagery. The modelled timings and locations of delivery of meltwater to the bed also match well with observed temporal and spatial patterns of ice surface speed-ups. This is particularly true for the lower catchment (
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- 2015
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49. Estimating Spring Terminus Submarine Melt Rates at a Greenlandic Tidewater Glacier Using Satellite Imagery
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Alexis N. Moyer, Peter W. Nienow, Noel Gourmelen, Andrew J. Sole, and Donald A. Slater
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submarine melt ,ice/ocean interactions ,tidewater glaciers ,remote sensing ,TanDEM-X ,Science - Abstract
Oceanic forcing of the Greenland Ice Sheet is believed to promote widespread thinning at tidewater glaciers, with submarine melting proposed as a potential trigger of increased glacier calving, retreat, and subsequent acceleration. The precise mechanism(s) driving glacier instability, however, remain poorly understood, and while increasing evidence points to the importance of submarine melting, estimates of melt rates are uncertain. Here we estimate submarine melt rate by examining freeboard changes in the seasonal ice tongue of Kangiata Nunaata Sermia (KNS) at the head of Kangersuneq Fjord (KF), southwest Greenland. We calculate melt rates for March and May 2013 by differencing along-fjord surface elevation, derived from high-resolution TanDEM-X digital elevation models (DEMs), in combination with ice velocities derived from offset tracking applied to TerraSAR-X imagery. Estimated steady state melt rates reach up to 1.4 ± 0.5 m d−1 near the glacier grounding line, with mean values of up to 0.8 ± 0.3 and 0.7 ± 0.3 m d−1 for the eastern and western parts of the ice tongue, respectively. Melt rates decrease with distance from the ice front and vary across the fjord. This methodology reveals spatio-temporal variations in submarine melt rates (SMRs) at tidewater glaciers which develop floating termini, and can be used to improve our understanding of ice-ocean interactions and submarine melting in glacial fjords.
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- 2017
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50. PERFORMANCE PRODUCTION OF STRAWBERRY IN ENVIRONMENT CULTIVATED WITH FIG TREE
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HELOISA FERRO CONSTÂNCIO MENDONÇA, EUNICE OLIVEIRA CALVETE, ROSIANI CASTOLDI DA COSTA, and ALEXANDRE AUGUSTO NIENOW
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Fragaria x ananassa Duch. ,phenology ,fruit production ,crop integration ,Plant culture ,SB1-1110 - Abstract
ABSTRACT The use of protected environment in horticulture has been increasingly used as it provides increased precocity and productivity, in addition to produce outside the normal growing season. Both woody species such as herbs are possible to cultivate in this environment. However fruit plants occupy large spaces with a short production period. The study aimed to test whether strawberry genotypes present different production peaks in cultivated environment with fig trees. The treatments consisted of strawberry cultivars Aromas, Albion, Camino Real, Camarosa and Ventana distributed in delineation of randomized blocks with four replications and with a population of 10 plants m-2. It was recorded precocity in cultivars Albion, Camarosa and Ventana, because they started flowering at 63 days after planting. Aromas and Camino Real were characterized as late. Aromas achieved greater total number of fruit, but with a lower percentage of commercial fruits in relation to the other cultivars. Peak production for all cultivars was found when there was an accumulation 2008 °C day -1, corresponding to the month of November. There were differences in performance production between strawberry cultivars conducted in the environment with fig tree, with different production peaks.
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- 2017
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