Read by QxMD icon Read


Elena Sugrue, Paul D Carr, Colin Scott, Colin J Jackson
The desolvation of ionizable residues in the active sites of enzymes and the subsequent effects on catalysis and thermostability have been studied in model systems, yet little is known regarding how enzymes can naturally evolve active sites with highly reactive and desolvated charges. Variants of triazine hydrolase (TrzN) with significant differences in their active sites have been isolated from different bacterial strains: TrzN from Nocardioides sp. strain MTD22 contains a catalytic glutamate residue (Glu241) that is surrounded by hydrophobic and aromatic second-shell residues (Pro214, Tyr215), whereas TrzN from Nocardioides sp...
October 21, 2016: Biochemistry
Xiangyi Zhang, Gavin O Jones, James L Hedrick, Robert M Waymouth
Ring-opening polymerization of lactones is a versatile approach to generate well-defined functional polyesters. Typical ring-opening catalysts are subject to a trade-off between rate and selectivity. Here we describe an effective catalytic system combining alkoxides with thioureas that catalyses rapid and selective ring-opening polymerizations. Deprotonation of thioureas by sodium, potassium or imidazolium alkoxides generates a hydrogen-bonded alcohol adduct of the thiourea anion (thioimidate). The ring-opening polymerization of L-lactide mediated by these alcohol-bonded thioimidates yields highly isotactic polylactide with fast kinetics and living polymerization behaviour, as evidenced by narrow molecular weight distributions (Mw/Mn < 1...
November 2016: Nature Chemistry
Daniel B Schwab, Armin P Moczek
The elaboration of exaggerated, sexually selected weapons and ornaments often comes at a cost to other traits. For instance, by sustaining the growth of an exaggerated weapon during development, shared and limited resources such as morphogens, growth factors, and nutrients may become depleted and limit the size to which other structures can grow. Such interactions are characteristic of resource allocation trade-offs, which can constrain the production of phenotypic variation and bias evolutionary trajectories...
October 21, 2016: Journal of Experimental Zoology. Part A, Ecological Genetics and Physiology
Patrycja Podlaszczuk, Maciej Kamiński, Radosław Włodarczyk, Krzysztof Kaczmarek, Tomasz Janiszewski, Piotr Minias
BACKGROUND: Moult is one of the most costly activities in the annual cycle of birds and most avian species separate moult from other energy-demanding activities, such as migration. To this end, young birds tend to undergo the first post-juvenile moult before the onset of migration, but in some species the time window for the pre-migratory feather replacement is too narrow. We hypothesized that in such species an increased investment in the structural quality of juvenile feathers may allow to retain juvenile plumage throughout the entire migratory period and delay moult until arriving at wintering grounds, thus avoiding a moult-migration overlap...
2016: Frontiers in Zoology
Marta R Pereira, Cristian S Dambros, Charles E Zartman
PREMISE OF THE STUDY: Resource allocation is difficult to characterize in plants because of the challenges of quantifying gametes and propagules. We surveyed six sympatric, unisexual species in the family Calymperaceae (Bryophyta) to test for trade-offs in prezygotic sexual and asexual expression and density-dependent survivorship of female gametangia. METHODS: We tallied gametangial and asexual propagule output for 1820 shoots from 17 populations of six species at monthly intervals during one year (2010-2011) in a central Amazonian forest...
October 7, 2016: American Journal of Botany
Sandra A Heldstab, Carel P van Schaik, Karin Isler
Humans stand out among non-aquatic mammals by having both an extremely large brain and a relatively large amount of body fat. To understand the evolution of this human peculiarity we report a phylogenetic comparative study of 120 mammalian species, including 30 primates, using seasonal variation in adult body mass as a proxy of the tendency to store fat. Species that rely on storing fat to survive lean periods are expected to be less active because of higher costs of locomotion and have increased predation risk due to reduced agility...
November 2016: Journal of Human Evolution
Prunella Blinman, Linda Mileshkin, Pearly Khaw, Geraldine Goss, Carol Johnson, Anne Capp, Susan Brooks, Gerard Wain, Ilka Kolodziej, Anne-Sophie Veillard, Rachel O'Connell, Carien L Creutzberg, Martin R Stockler
BACKGROUND: To determine the minimum survival benefits that patients, and their clinicians, judged sufficient to make adjuvant chemotherapy (ACT) worthwhile, in addition to pelvic radiotherapy, for women with high risk and advanced stage endometrial cancer. METHODS: Eighty-three participants in the PORTEC-3 trial completed a time trade-off questionnaire before and after adjuvant therapy; 44 of their clinicians completed it once only. The questionnaire used four hypothetical scenarios including baseline survival times without ACT of 5 and 8 years, and baseline survival rates at 5 years without ACT of 50 and 65%...
October 20, 2016: British Journal of Cancer
Matthieu Barbier, James R Watson
Predators of all kinds, be they lions hunting in the Serengeti or fishermen searching for their catch, display various collective strategies. A common strategy is to share information about the location of prey. However, depending on the spatial characteristics and mobility of predators and prey, information sharing can either improve or hinder individual success. Here, our goal is to investigate the interacting effects of space and information sharing on predation efficiency, represented by the expected rate at which prey are found and consumed...
October 2016: PLoS Computational Biology
Maria Agapova, Brian B Bresnahan, Mitchell Higashi, Larry Kessler, Louis P Garrison, Beth Devine
The American College of Radiology develops evidence-based practice guidelines to aid appropriate utilization of radiological procedures. Panel members use expert opinion to weight trade-offs and consensus methods to rate appropriateness of imaging tests. These ratings include an equivocal range, assigned when there is disagreement about a technology's appropriateness and the evidence base is weak or for special circumstances. It is not clear how expert consensus merges with the evidence base to arrive at an equivocal rating...
October 19, 2016: Journal of Evaluation in Clinical Practice
Atsushi Nakagomi, Sho Okada, Toshihiro Shoji, Yoshio Kobayashi
Our aim was to assess the discrepancy in the blood pressure amplification (BPA) value defined as the aortic-to-brachial increase in systolic BP (SBP) between invasive and noninvasive brachial cuff-based methods. In 45 patients undergoing cardiac catheterization, BP in the brachial artery and ascending aorta were measured with an invasive catheter and a brachial cuff-based oscillometric device. To calculate aortic SBP, brachial waveforms were calibrated by the brachial systolic and diastolic BP (DBP) (C1 calibration) or by the brachial mean BP and DBP (C2 calibration)...
October 20, 2016: Hypertension Research: Official Journal of the Japanese Society of Hypertension
Jakub Tomek, Rebecca A B Burton, Gil Bub
Cardiac arrhythmias are one of the most frequent causes of death worldwide. A popular biological model used to study arrhythmogenesis is the cultured cardiac cell monolayer, which provides a good trade-off between physiological relevance and experimental access. Excitation wave patterns are imaged using high-bandwidth detectors, producing large data sets that are typically analyzed manually. To make such analysis less time consuming and less subjective, we have designed and implemented a toolkit for segmentation and tracking of cardiac waves in optical mapping recordings...
October 18, 2016: Biophysical Journal
Ewa Szwejser, B M Lidy Verburg-van Kemenade, Magdalena Maciuszek, Magdalena Chadzinska
Clinical and experimental evidence shows that estrogens affect immunity in mammals. Less is known about this interaction in the evolutionary older, non-mammalian, vertebrates. Fish form an excellent model to identify evolutionary conserved neuroendocrine-immune interactions: i) they are the earliest vertebrates with fully developed innate and adaptive immunity, ii) immune and endocrine parameters vary with season iii) physiology is constantly disrupted by increasing contamination of the aquatic environment...
October 16, 2016: Hormones and Behavior
Maxime Cailleret, Steven Jansen, Elisabeth M R Robert, Lucía Desoto, Tuomas Aakala, Joseph A Antos, Barbara Beikircher, Christof Bigler, Harald Bugmann, Marco Caccianiga, Vojtěch Čada, J Julio Camarero, Paolo Cherubini, Hervé Cochard, Marie R Coyea, Katarina Čufar, Adrian J Das, Hendrik Davi, Sylvain Delzon, Michael Dorman, Guillermo Gea-Izquierdo, Sten Gillner, Laurel J Haavik, Henrik Hartmann, Ana-Maria Hereş, Kevin R Hultine, Pavel Janda, Jeffrey M Kane, Vyacheslav I Kharuk, Thomas Kitzberger, Tamir Klein, Koen Kramer, Frederic Lens, Tom Levanic, Juan Carlos Linares Calderon, Francisco Lloret, Raquel Lobo-Do-Vale, Fabio Lombardi, Rosana López Rodríguez, Harri Mäkinen, Stefan Mayr, Ilona Mészáros, Juha M Metsaranta, Francesco Minunno, Walter Oberhuber, Andreas Papadopoulos, Mikko Peltoniemi, Any Mary Petritan, Brigitte Rohner, Gabriel Sangüesa-Barreda, Dimitrios Sarris, Jeremy M Smith, Amanda B Stan, Frank Sterck, Dejan B Stojanović, Maria Laura Suarez, Miroslav Svoboda, Roberto Tognetti, José M Torres-Ruiz, Volodymyr Trotsiuk, Ricardo Villalba, Floor Vodde, Alana R Westwood, Peter H Wyckoff, Nikolay Zafirov, Jordi Martínez-Vilalta
Tree mortality is a key factor influencing forest functions and dynamics, but our understanding of the mechanisms leading to mortality and the associated changes in tree growth rates are still limited. We compiled a new pan-continental tree-ring width database from sites where both dead and living trees were sampled (2,970 dead and 4,224 living trees from 190 sites, including 36 species), and compared early and recent growth rates between trees that died and those that survived a given mortality event. We observed a decrease in radial growth before death in ca...
October 19, 2016: Global Change Biology
Louise M Alissa, Danilo G Muniz, Glauco Machado
When there is a temporal trade-off between mating effort and parental care, theoretical models predict that intense sexual selection on males leads to reduced paternal care. Thus, high-quality males should invest more in mating effort because they have higher chances of acquiring mates, whereas low-quality males should bias their investment toward parental care. Once paternal care has evolved, offspring value should also influence males' decisions to invest in offspring attendance. Here we performed a manipulation under field conditions to investigate the factors that influence male allocation in either mating effort or parental care...
October 18, 2016: Journal of Evolutionary Biology
Laure Spieser, Mathieu Servant, Thierry Hasbroucq, Borís Burle
Both in real life and experimental settings, increasing response speed typically leads to more error-prone actions. Processes underlying such a "speed-accuracy trade-off" (SAT) are usually assumed to be purely decisional: cautiousness would be determined only by the amount of sensory evidence required to select a response. The present data challenges this largely accepted view, by directly showing that motor processes are speeded up under time pressure. In a choice reaction time task where emphasis was put either on response speed or accuracy, motor processes were investigated through the analysis of muscular activity related to response execution...
October 18, 2016: Psychonomic Bulletin & Review
Linda J Gormezano, Scott R McWilliams, David T Iles, Robert F Rockwell
Trade-offs between locomotory costs and foraging gains are key elements in determining constraints on predator-prey interactions. One intriguing example involves polar bears pursuing snow geese on land. As climate change forces polar bears to spend more time ashore, they may need to expend more energy to obtain land-based food. Given that polar bears are inefficient at terrestrial locomotion, any extra energy expended to pursue prey could negatively impact survival. However, polar bears have been regularly observed engaging in long pursuits of geese and other land animals, and the energetic worth of such behaviour has been repeatedly questioned...
2016: Conservation Physiology
Oliver R Wearn, Chris Carbone, J Marcus Rowcliffe, Henry Bernard, Robert M Ewers
Diversity responses to land-use change are poorly understood at local scales, hindering our ability to make forecasts and management recommendations at scales which are of practical relevance. A key barrier in this has been the underappreciation of grain-dependent diversity responses and the role that β-diversity (variation in community composition across space) plays in this. Decisions about the most effective spatial arrangement of conservation set-aside, for example high conservation value areas, have also neglected β-diversity, despite its role in determining the complementarity of sites...
July 2016: Ecological Applications: a Publication of the Ecological Society of America
Simone Vincenzi, Alain J Crivelli, Stephan Munch, Hans J Skaug, Marc Mangel
Better understanding of variation in growth will always be an important problem in ecology. Individual variation in growth can arise from a variety of processes; for example, individuals within a population vary in their intrinsic metabolic rates and behavioral traits, which may influence their foraging dynamics and access to resources. However, when adopting a growth model, we face trade-offs between model complexity, biological interpretability of parameters, and goodness of fit. We explore how different formulations of the von Bertalanffy growth function (vBGF) with individual random effects and environmental predictors affect these trade-offs...
July 2016: Ecological Applications: a Publication of the Ecological Society of America
Jeffrey D Kline, Mark E Harmon, Thomas A Spies, Anita T Morzillo, Robert J Pabst, Brenda C McComb, Frank Schnekenburger, Keith A Olsen, Blair Csuti, Jody C Vogeler
Forest policymakers and managers have long sought ways to evaluate the capability of forest landscapes to jointly produce timber, habitat, and other ecosystem services in response to forest management. Currently, carbon is of particular interest as policies for increasing carbon storage on federal lands are being proposed. However, a challenge in joint production analysis of forest management is adequately representing ecological conditions and processes that influence joint production relationships. We used simulation models of vegetation structure, forest sector carbon, and potential wildlife habitat to characterize landscape-level joint production possibilities for carbon storage, timber harvest, and habitat for seven wildlife species across a range of forest management regimes...
October 2016: Ecological Applications: a Publication of the Ecological Society of America
Christopher E Cattau, Robert J Fletcher, Brian E Reichert, Wiley M Kitchens
Identifying impacts of non-native species on native populations is central to conservation and ecology. While effects of non-native predators on native prey populations have recently received much attention, impacts of introduced prey on native predator populations are less understood. Non-native prey can influence predator behavior and demography through direct and indirect pathways, yet quantitative assessments of the relative impacts of multiple, potentially counteracting, effects on native predator population growth remain scarce...
October 2016: Ecological Applications: a Publication of the Ecological Society of America
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"