bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of dental students' performances and perceptions in preclinical and clinical pharmacology in an Irish Dental School
Authors: Barry O. P. , O'Sullivan E. 
Published: May 2016

AbstractIntroductionKnowledge of pharmacology is essential for dental students and for its safe application in the clinical environment.AimsThe goals of our study were to assess dental students' performances in pharmacology with and without shared instruction, to investigate correlations between students' final grades in pre‐clinical and clinical pharmacology, to determine if gender affects test performance and to explore characteristics of effective dental student learning.MethodsA 9 year mixed method study was undertaken comprising (i) quantitative analysis of undergraduate performances in basic and clinical pharmacology (n = 320) and (ii) quantitative and qualitative exploration of student perceptions on teaching and learning in pharmacology.ResultsMean basic pharmacology scores were not significantly different when dental students were co‐taught with medical and pharmacy students. Regression analysis showed a statistically significant correlation (r = 0.582, P < 0.01) between basic and clinical pharmacology dental student scores. Interestingly, correlation was independent of gender with female student scores demonstrating a correlation of r = 0.480, P < 0.01 and males a correlation of 0.684, P < 0.01. Quantitative and qualitative feedback highlighted four thematic areas of effective dental student learning namely: (i) quality of instructors, (ii) lecture content, (iii) assessment type and (iv) learning environment.ConclusionsTeaching basic pharmacology in a multidisciplinary environment did not adversely affect dental students' examination performances. Dental students who perform well in basic pharmacology perform similarly well in clinical pharmacology. However, whether students' understanding and the application of pharmacology affects the quality of patient care in the clinical environment awaits further investigation.
Calcium dynamics predict direction of synaptic plasticity in striatal spiny projection neurons
Authors: Jędrzejewska‐Szmek Joanna , Damodaran Sriraman , Dorman Daniel B. , Blackwell Kim T. 
Published: May 2016

AbstractThe striatum is a major site of learning and memory formation for sensorimotor and cognitive association. One of the mechanisms used by the brain for memory storage is synaptic plasticity – the long‐lasting, activity‐dependent change in synaptic strength. All forms of synaptic plasticity require an elevation in intracellular calcium, and a common hypothesis is that the amplitude and duration of calcium transients can determine the direction of synaptic plasticity. The utility of this hypothesis in the striatum is unclear in part because dopamine is required for striatal plasticity and in part because of the diversity in stimulation protocols. To test whether calcium can predict plasticity direction, we developed a calcium‐based plasticity rule using a spiny projection neuron model with sophisticated calcium dynamics including calcium diffusion, buffering and pump extrusion. We utilized three spike timing‐dependent plasticity (STDP) induction protocols, in which postsynaptic potentials are paired with precisely timed action potentials and the timing of such pairing determines whether potentiation or depression will occur. Results show that despite the variation in calcium dynamics, a single, calcium‐based plasticity rule, which explicitly considers duration of calcium elevations, can explain the direction of synaptic weight change for all three STDP protocols. Additional simulations show that the plasticity rule correctly predicts the NMDA receptor dependence of long‐term potentiation and the L‐type channel dependence of long‐term depression. By utilizing realistic calcium dynamics, the model reveals mechanisms controlling synaptic plasticity direction, and shows that the dynamics of calcium, not just calcium amplitude, are crucial for synaptic plasticity.
A global synthesis of the rate and temperature sensitivity of soil nitrogen mineralization: latitudinal patterns and mechanisms
Authors: Liu Yuan , Wang Changhui , He Nianpeng , Wen Xuefa , Gao Yang , Li Shenggong , Niu Shuli , Butterbach‐Bahl Klaus , Luo Yiqi , Yu Guirui 
Published: May 2016

AbstractSoil net nitrogen (N) mineralization (Nmin) is a pivotal process in the global N cycle regulating the N availability of plant growth. Understanding the spatial patterns of Nmin, its temperature sensitivity (Q10) and regulatory mechanisms is critical for improving the management of soil nutrients. In this study, we evaluated 379 peer‐reviewed scientific papers to explore how Nmin and the Q10 of Nmin varied among different ecosystems and regions at the global scale. The results showed that Nmin varied significantly among different ecosystems with a global average of 2.41 mg N soil kg−1 day−1. Furthermore, Nmin significantly decreased with increasing latitude and altitude. The Q10 varied significantly among different ecosystems with a global average of 2.21, ranging from the highest found in forest soils (2.43) and the lowest found for grassland soils (1.67) and significantly increased with increasing latitude. Path analyses indicated that Nmin was primarily affected by the content of soil organic carbon (C), soil C:N ratio, and clay content, where Q10 was primarily influenced by the soil C:N ratio and soil pH. Furthermore, the activation energy (Ea) of soil N mineralization was significantly and negative correlated with the substrate quality index among all ecosystems, indicating the applicability of the carbon quality temperature hypothesis to soil N mineralization at a global scale. These findings provided empirical evidence supporting that soil N availability, under global warming scenarios, is expected to increase stronger in colder regions as compared with that low‐latitude regions due to the higher Q10. This may alleviate the restriction of N supply for increased primary productivity at higher latitudes.
Impact of pollen resources drift on common bumblebees in NW Europe
Authors: Roger Nathalie , Moerman Romain , Carvalheiro Luísa Gigante , Aguirre‐Guitiérrez Jesús , Jacquemart Anne‐Laure , Kleijn David , Lognay Georges , Moquet Laura , Quinet Muriel , Rasmont Pierre , Richel Aurore , Vanderplanck Maryse , Michez Denis 
Published: May 2016

AbstractSeveral bee species are experiencing significant population declines. As bees exclusively rely on pollen for development and survival, such declines could be partly related to changes in their host plant abundance and quality. Here, we investigate whether generalist bumblebee species, with stable population trends over the past years, adapted their diets in response to changes in the distribution and chemical quality of their pollen resources. We selected five common species of bumblebee in NW Europe for which we had a precise description of their pollen diet through two time periods (‘prior to 1950’ and ‘2004–2005’). For each species, we assessed whether the shift in their pollen diet was related with the changes in the suitable area of their pollen resources. Concurrently, we evaluated whether the chemical composition of pollen resources changed over time and experimentally tested the impact of new major pollen species on the development of B. terrestris microcolonies. Only one species (i.e. B. lapidarius) significantly included more pollen from resources whose suitable area expanded. This opportunist pattern could partly explain the expansion of B. lapidarius in Europe. Regarding the temporal variation in the chemical composition of the pollen diet, total and essential amino acid contents did not differ significantly between the two time periods while we found significant differences among plant species. This result is driven by the great diversity of resources used by bumblebee species in both periods. Our bioassay revealed that the shift to new major pollen resources allowed microcolonies to develop, bringing new evidence on the opportunist feature of bumblebee in their diets. Overall, this study shows that the response to pollen resource drift varies among closely related pollinators, and a species‐rich plant community ensures generalist species to select a nutrient‐rich pollen diet.
Effects of temperature variability on community structure in a natural microbial food web
Authors: Zander Axel , Bersier Louis‐Félix , Gray Sarah M. 
Published: May 2016

AbstractClimate change research has demonstrated that changing temperatures will have an effect on community‐level dynamics by altering species survival rates, shifting species distributions, and ultimately, creating mismatches in community interactions. However, most of this work has focused on increasing temperature, and still little is known about how the variation in temperature extremes will affect community dynamics. We used the model aquatic community held within the leaves of the carnivorous plant, Sarracenia purpurea, to test how food web dynamics will be affected by high temperature variation. We tested the community response of the first (bacterial density), second (protist diversity and composition), and third trophic level (predator mortality), and measured community respiration. We collected early and late successional stage inquiline communities from S. purpurea from two North American and two European sites with similar average July temperature. We then created a common garden experiment in which replicates of these communities underwent either high or normal daily temperature variation, with the average temperature equal among treatments. We found an impact of temperature variation on the first two, but not on the third trophic level. For bacteria in the high‐variation treatment, density experienced an initial boost in growth but then decreased quickly through time. For protists in the high‐variation treatment, alpha‐diversity decreased faster than in the normal‐variation treatment, beta‐diversity increased only in the European sites, and protist community composition tended to diverge more in the late successional stage. The mortality of the predatory mosquito larvae was unaffected by temperature variation. Community respiration was lower in the high‐variation treatment, indicating a lower ecosystem functioning. Our results highlight clear impacts of temperature variation. A more mechanistic understanding of the effects that temperature, and especially temperature variation, will have on community dynamics is still greatly needed.
Blood Pressure Responses to Endovascular Stimulation: A Potential Therapy for Autonomic Disorders With Vasodilatation
Authors: NAKSUK NIYADA , KILLU AMMAR M. , YOGESWARAN VIDHUSHEI , DESIMONE CHRISTOPHER V. , SUDDENDORF SCOTT H. , LADEWIG DOROTHY J. , POWERS JOANNE M. , WEBER SARAH , MADHAVAN MALINI , CHA YONG‐MEI , KAPA SURAJ , ASIRVATHAM SAMUEL J. 
Published: May 2016

Endovascular Stimulation for Treatment of HypotensionBackgroundWe have previously shown that sympathetic ganglia stimulation via the renal vein rapidly increases blood pressure. This study further investigated the optimal target sites and effective energy levels for stimulation of the renal vasculatures and nearby sympathetic ganglia for rapid increase in blood pressure.MethodsThe pre‐study protocol for endovascular stimulations included 2 minutes of stimulation (1–150 V and 10 pulses per second) and at least 2 minutes of rest during poststimulation. If blood pressure and/or heart rate were changed during the stimulation, time to return to baseline was allowed prior to the next stimulation.ResultsIn 11 acute canine studies, we performed 85 renal artery, 30 renal vein, and 8 hepatic vasculature stimulations. The mean arterial pressure (MAP) rapidly increased during stimulation of renal artery (95 ± 18 mmHg vs. 103 ± 15 mmHg; P < 0.0001), renal vein (90 ± 16 mmHg vs. 102 ± 20 mmHg; P = 0.001), and hepatic vasculatures (74 ± 8 mmHg vs. 82 ± 11 mmHg; P = 0.04). Predictors of a significant increase in MAP were energy >10 V focused on the left renal artery, bilateral renal arteries, and bilateral renal veins (especially the mid segment). Overall, heart rate was unchanged, but muscle fasciculation was observed in 22.0% with an output >10 V (range 15–150 V). Analysis after excluding the stimulations that resulted in fasciculation yielded similar results to the main findings.ConclusionsStimulation of intra‐abdominal vasculatures promptly increased the MAP and thus may be a potential treatment option for hypotension in autonomic disorders. Predictors of optimal stimulation include energy delivery and the site of stimulation (for the renal vasculatures), which informs the design of subsequent research.
Efficacy of Left Atrial Voltage‐Based Catheter Ablation of Persistent Atrial Fibrillation
Authors: YAMAGUCHI TAKANORI , TSUCHIYA TAKESHI , NAKAHARA SHIRO , FUKUI AKIRA , NAGAMOTO YASUTSUGU , MUROTANI KENTA , ESHIMA KENICHI , TAKAHASHI NAOHIKO 
Published: May 2016

Low Voltage‐Based Ablation for Atrial FibrillationBackgroundLow‐voltage zones (LVZs) represent fibrotic tissue and are substrates for atrial fibrillation (AF). We hypothesized that LVZ‐based substrate modification along with pulmonary vein isolation (PVI) would improve outcomes in persistent AF (PeAF) patients with LVZs, whereas PVI alone would work in patients without LVZs.Methods and ResultsVoltage mapping of the left atrium (LA) was performed during sinus rhythm in 101 PeAF patients in whom LVZ was defined as an area with bipolar electrograms <0.5 mV. Thirty‐nine patients had LVZs and underwent ablation of the entire LVZ area after PVI (LVZabl group). In the remaining 62 patients without LVZs, PVI alone was performed with no further substrate modifications (PVI group). An additional group of 16 consecutive PeAF patients with LVZ did not undergo any substrate modification after PVI and were used as a comparison group (LVZnon‐abl group) despite having similar size of LVZs to that in the LVZabl group. After a single session, 28 (72%) patients in the LVZabl group had no recurrence, whereas 49 (79%) patients in the PVI group had no recurrence during 18 ± 7 months of follow‐up (log‐rank, P = 0.400). In the LVZnon‐abl group, only 6 patients (38%) had no recurrence during 32 ± 7 months of follow‐up, even after a mean number of sessions of 1.8 (log‐rank, P < 0.001, compared with the LVZabl group).ConclusionsAdditional LVZ‐based substrate modification after PVI improved the outcome in PeAF patients with LVZs, whereas PVI alone worked in patients without LVZs, even in those with PeAF.
Low‐Level But Not High‐Level Baroreceptor Stimulation Inhibits Atrial Fibrillation in a Pig Model of Sleep Apnea
Authors: LINZ DOMINIK , HOHL MATHIAS , KHOSHKISH SHAYAN , MAHFOUD FELIX , UKENA CHRISTIAN , NEUBERGER HANS‐RUPRECHT , WIRTH KLAUS , BÖHM MICHAEL 
Published: May 2016

Baroreflex Stimulation and Atrial FibrillationBackgroundObstructive sleep apnea (OSA) increases susceptibility to atrial fibrillation (AF) by a combined sympatho‐vagal hyperactivation. The purpose of this study was to investigate the effect of autonomic nervous system modulation by low‐level baroreceptor stimulation (LL‐BRS) compared to high‐level BRS (HL‐BRS) on atrial arrhythmogenic changes in a pig model of OSA.Methods and ResultsSixteen pigs received tracheotomy under general urethane/chloralose anesthesia. Group 1 pigs (n = 8) received LL‐BRS (at 80% of that slowing sinus rate) for 3 hours and group 2 pigs (n = 8) received HL‐BRS (slowing sinus rate). Changes in atrial effective refractory period (AERP) and AF‐inducibility were determined during applied negative thoracic pressure (NTP) for 2 minutes before and at the end of the 3‐hour stimulation protocol. Group 1: LL‐BRS prolonged AERP from 150 ± 5 to 172 ± 19 milliseconds (P < 0.001). After 3 hours of LL‐BRS, NTP‐induced AERP‐shortening was diminished from –51 ± 10 milliseconds (–34%) to –22 ± 4 milliseconds (–13%) (P < 0.01). AF‐inducibility during NTP maneuvers decreased from 90% at baseline to 15% (P < 0.01). Group 2: HL‐BRS shortened AERP from 150 ± 17 to 132 ± 8 milliseconds (P = 0.024). After 3 hours of HL‐BRS, NTP‐induced AERP‐shortening was increased from –55 ± 7 milliseconds (–36%) to –72 ± 11 milliseconds (–54%) (P < 0.05) and AF‐inducibility was not affected. NTP‐induced changes in blood gases and blood pressure were not different between the groups.ConclusionLL‐BRS suppressed NTP‐induced AERP‐shortening and AF‐inducibility. By contrast HL‐BRS further perpetuated NTP‐induced AERP‐shortening and increased AF‐inducibility. These findings support only the use of LL‐BRS as a novel therapeutic modality to treat AF in OSA.
Reinforcement and a cline in mating behaviour evolve in response to secondary contact and hybridization in shield‐back katydids (Orthoptera: Tettigoniidae)
Authors: Cole J. A. 
Published: May 2016

AbstractIn a dispersal‐limited species that has evolved reproductive character displacement at a contact zone, a cline in mating behaviour may result if gene flow diffuses alleles out of the contact zone into allopatric populations. Prior work has found such a clinal pattern in the shield‐back katydid Aglaothorax morsei, in which the male calling songs in a sympatric population have a displaced, short interpulse interval that increases in length with increasing distance from the contact zone. In this study, molecular phylogenetic and female preference data show that (1) sympatric populations result from secondary contact, (2) hybridization in sympatry has resulted in unidirectional mitochondrial introgression and (3) female preferences are consistent with reproductive character displacement and could generate a cline in mating behaviour. These data together suggest a history of reinforcement, generally considered rare in acoustically communicating insects; thus, Aglaothorax represents an important example of a rarely documented evolutionary process.
Genetic structure of phenotypic robustness in the collaborative cross mouse diallel panel
Authors: Gonzalez P. N. , Pavlicev M. , Mitteroecker P. , Pardo‐Manuel de Villena F. , Spritz R. A. , Marcucio R. S. , Hallgrímsson B. 
Published: May 2016

AbstractDevelopmental stability and canalization describe the ability of developmental systems to minimize phenotypic variation in the face of stochastic micro‐environmental effects, genetic variation and environmental influences. Canalization is the ability to minimize the effects of genetic or environmental effects, whereas developmental stability is the ability to minimize the effects of micro‐environmental effects within individuals. Despite much attention, the mechanisms that underlie these two components of phenotypic robustness remain unknown. We investigated the genetic structure of phenotypic robustness in the collaborative cross (CC) mouse reference population. We analysed the magnitude of fluctuating asymmetry (FA) and among‐individual variation of cranial shape in reciprocal crosses among the eight parental strains, using geometric morphometrics and a diallel analysis based on a Bayesian approach. Significant differences among genotypes were found for both measures, although they were poorly correlated at the level of individuals. An overall positive effect of inbreeding was found for both components of variation. The strainCAST/EiJ exerted a positive additive effect onFAand, to a lesser extent, among‐individual variance. Sex‐ and other strain‐specific effects were not significant. NeitherFAnor among‐individual variation was associated with phenotypic extremeness. Our results support the existence of genetic variation for both developmental stability and canalization. This finding is important because robustness is a key feature of developmental systems. Our finding that robustness is not related to phenotypic extremeness is consistent with theoretical work that suggests that its relationship to stabilizing selection is not straightforward.
Ornament size and colour as alternative strategies for effective communication in gliding lizards
Authors: Klomp D. A. , Ord T. J. , Das I. , Diesmos A. , Ahmad N. , Stuart‐Fox D. 
Published: May 2016

AbstractSexual ornamentation needs to be conspicuous to be effective in attracting potential mates and defending territories and indeed, a multitude of ways exists to achieve this. Two principal mechanisms for increasing conspicuousness are to increase the ornament's colour or brightness contrast against the background and to increase the size of the ornament. We assessed the relationship between the colour and size of the dewlap, a large extendible throat‐fan, across a range of species of gliding lizards (Agamidae; genus Draco) from Malaysia and the Philippines. We found a negative relationship across species between colour contrast against the background and dewlap size in males, but not in females, suggesting that males of different species use increasing colour contrast and dewlap size as alternative strategies for effective communication. Male dewlap size also increases with increasing sexual size dimorphism, and dewlap colour and brightness contrast increase with increasing sexual dichromatism in colour and brightness, respectively, suggesting that sexual selection may act on both dewlap size and colour. We further found evidence that relative predation intensity, as measured from predator attacks on models placed in the field, may play a role in the choice of strategy (high chromatic contrast or large dewlap area) a species employs. More broadly, these results highlight that each component in a signal (such as colour or size) may be influenced by different selection pressures and that by assessing components individually, we can gain a greater understanding of the evolution of signal diversity.
Histories of host shifts and cospeciation among free‐living parasitoids of Rhagoletis flies
Authors: Hamerlinck G. , Hulbert D. , Hood G. R. , Smith J. J. , Forbes A. A. 
Published: May 2016

AbstractHost shifts by specialist insects can lead to reproductive isolation between insect populations that use different hosts, promoting diversification. When both a phytophagous insect and its ancestrally associated parasitoid shift to the same novel host plant, they may cospeciate. However, because adult parasitoids are free living, they can also colonize novel host insects and diversify independent of their ancestral host insect. Although shifts of parasitoids to new insect hosts have been documented in ecological time, the long‐term importance of such shifts to parasitoid diversity has not been evaluated. We used a genus of flies with a history of speciation via host shifting (Rhagoletis [Diptera: Tephritidae]) and three associated hymenopteran parasitoid genera (Diachasma, Coptera and Utetes) to examine cophylogenetic relationships between parasitoids and their host insects. We inferred phylogenies of Rhagoletis, Diachasma, Coptera and Utetes and used distance‐based cophylogenetic methods (ParaFit and PACo) to assess congruence between fly and parasitoid trees. We used an event‐based method with a free‐living parasitoid cost model to reconstruct cophylogenetic histories of each parasitoid genus and Rhagoletis. We found that the current species diversity and host–parasitoid associations between the Rhagoletis flies and parasitoids are the primary result of ancient cospeciation events. Parasitoid shifts to ancestrally unrelated hosts primarily occur near the branch tips, suggesting that host shifts contribute to recent parasitoid species diversity but that these lineages may not persist over longer time periods. Our analyses also stress the importance of biologically informed cost models when investigating the coevolutionary histories of hosts and free‐living parasitoids.