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40Ar/39Ar and paleomagnetic constraints on the age and areal extent of the Picabo volcanic field: Implications for the Yellowstone hotspot
(Geosphere, 2019) Anders, Mark H.; DiVenere, Viktor J.; Hemming, Sidney R.; Gombiner, Joel
The Picabo volcanic field is one of the key silicic volcanic fields in the time-transgressive track of the Yellowstone hotspot. The Picabo volcanic field is also one of the most poorly defined volcanic fields along the track of the Yellowstone hotspot. Determining the age and areal extent of the Picabo volcanic field ignimbrites is one of the primary objectives of this study. In our effort to correlate ignimbrites within the Picabo volcanic field as well as identify those from the neighboring Twin Falls and Heise volcanic fields, we present new petrographic, 40Ar/39Ar, and paleomagnetic data. With these data, we correlated several ignimbrites within the Picabo volcanic field. In some cases, we correlate units previously thought to be in the Picabo volcanic field to older volcanic fields. This includes the Picabo Tuff, which we suggest originates from the Twin Falls volcanic field rather from its namesake volcanic field. The first and best documented major silicic eruption of the volcanic field, the Arbon Valley Tuff, is also the largest ignimbrite in the Picabo volcanic field. There is disagreement as to whether the Arbon Valley Tuff is the result of a single ignimbrite eruption or multiple eruptions. We previously have suggested that the Arbon Valley Tuff is the result of two eruptions, one at 10.41 ± 0.01 Ma and the other at 10.22 ± 0.01 Ma (Anders et al., 2014). Those combining radiometric dates into a single eruption age report ages of 10.2 Ma, 10.27 ± 0.01 Ma, 10.34 ± 0.03 Ma, and 10.44 ± 0.27 Ma. We also suggest the final eruption of the Picabo volcanic field was the tuff of American Falls dated at 7.58 ± 0.02 Ma. Estimates of the location of Picabo volcanic field have been used to mark a major change in the migration rate of the Yellowstone–Snake River Plain silicic volcanic system. Based on our new data, we found only minor changes of the boundaries of the Picabo volcanic field from previous studies. Using the age of the Arbon Valley Tuff (10.41 Ma), we calculated an extension-corrected migration rate of 2.27 ± 0.2 cm/yr between the position of the Picabo volcanic field and that of the Yellowstone volcanic field over the past ~10 m.y. This estimate is close to the extension corrected 2.38 ± 0.21 cm/yr value based on the migration of the hotspot deformation field. These rates are consistent with independent estimates of North American plate velocity over the past 10 m.y. and therefore consistent with a fixed reference frame for the Yellowstone hotspot. These results stand in contrast with several recent models for the evolution of the Yellowstone–Snake River Plain volcanic system.
A computational model of pattern separation efficiency in the dentate gyrus with implications in schizophrenia
(Frontiers Media, 2015-03-25) Faghihi, Faramarz; Moustafa, Ahmed A.
Information processing in the hippocampus begins by transferring spiking activity of the entorhinal cortex (EC) into the dentate gyrus (DG). Activity pattern in the EC is separated by the DG such that it plays an important role in hippocampal functions including memory. The structural and physiological parameters of these neural networks enable the hippocampus to be efficient in encoding a large number of inputs that animals receive and process in their life time. The neural encoding capacity of the DG depends on its single neurons encoding and pattern separation efficiency. In this study, encoding by the DG is modeled such that single neurons and pattern separation efficiency are measured using simulations of different parameter values. For this purpose, a probabilistic model of single neurons efficiency is presented to study the role of structural and physiological parameters. Known neurons number of the EC and the DG is used to construct a neural network by electrophysiological features of granule cells of the DG. Separated inputs as activated neurons in the EC with different firing probabilities are presented into the DG. For different connectivity rates between the EC and DG, pattern separation efficiency of the DG is measured. The results show that in the absence of feedback inhibition on the DG neurons, the DG demonstrates low separation efficiency and high firing frequency. Feedback inhibition can increase separation efficiency while resulting in very low single neuron’s encoding efficiency in the DG and very low firing frequency of neurons in the DG (sparse spiking). This work presents a mechanistic explanation for experimental observations in the hippocampus, in combination with theoretical measures. Moreover, the model predicts a critical role for impaired inhibitory neurons in schizophrenia where deficiency in pattern separation of the DG has been observed.
A continuum of compass spin models on the honeycomb lattice
(New Journal of Physics, 2016-05) Zhao, Erhai; Zou, Haiyuan; Liu, Bo; Liu, W Vincent
Quantum spin models with spatially dependent interactions, known as compass models, play an important role in the study of frustrated quantum magnetism. One example is the Kitaev model on the honeycomb lattice with spin-liquid (SL) ground states and anyonic excitations. Another example is the geometrically frustrated quantum 120° model on the same lattice whose ground state has not been unambiguously established. To generalize the Kitaev model beyond the exactly solvable limit and connect it with other compass models, we propose a new model, dubbed 'the tripod model', which contains a continuum of compass-type models. It smoothly interpolates the Ising model, the Kitaev model, and the quantum 120° model by tuning a single parameter ${\theta }^{\prime }$, the angle between the three legs of a tripod in the spin space. Hence it not only unifies three paradigmatic spin models, but also enables the study of their quantum phase transitions. We obtain the phase diagram of the tripod model numerically by tensor networks in the thermodynamic limit. We show that the ground state of the quantum 120° model has long-range dimer order. Moreover, we find an extended spin-disordered (SL) phase between the dimer phase and an antiferromagnetic phase. The unification and solution of a continuum of frustrated spin models as outline here may be useful to exploring new domains of other quantum spin or orbital models.
A G protein‐coupled α7 nicotinic receptor regulates signaling and TNF‐α release in microglia
(FEBS Open Bio, 2017-07) King, Justin R.; Gillevet, Trudy C.; Kabbani, Nadine
Acetylcholine activation of α7 nicotinic acetylcholine receptors (α7 nAChRs) in microglia attenuates neuroinflammation and regulates TNF‐α release. We used lipopolysaccharide to model inflammation in the microglial cell line EOC20 and examined signaling by the α7 nAChR. Co‐immunoprecipitation experiments confirm that α7 nAChRs bind heterotrimeric G proteins in EOC20 cells. Interaction with Gαi mediates α7 nAChR signaling via enhanced intracellular calcium release and a decrease in cAMP, p38 phosphorylation, and TNF‐α release. These α7 nAChR effects were blocked by the inhibition of Gαi signaling via pertussis toxin, PLC activity with U73122, and α7 nAChR channel activity with the selective antagonist α‐bungarotoxin. Moreover, α7 nAChR signaling in EOC20 cells was significantly diminished by the expression of a dominant‐negative α7 nAChR, α7345‐8A, shown to be impaired in G protein binding. These findings indicate an essential role for G protein coupling in α7 nAChR function in microglia leading to the regulation of inflammation in the nervous system.
A Neural Mechanism for Background Information-Gated Learning Based on Axonal-Dendritic Overlaps
(Public Library of Science, 2015-03-13) Mainetti, Matteo; Ascoli, Giorgio A.
Experiencing certain events triggers the acquisition of new memories. Although necessary, however, actual experience is not sufficient for memory formation. One-trial learning is also gated by knowledge of appropriate background information to make sense of the experienced occurrence. Strong neurobiological evidence suggests that long-term memory storage involves formation of new synapses. On the short time scale, this form of structural plasticity requires that the axon of the pre-synaptic neuron be physically proximal to the dendrite of the post-synaptic neuron. We surmise that such “axonal-dendritic overlap” (ADO) constitutes the neural correlate of background information-gated (BIG) learning. The hypothesis is based on a fundamental neuroanatomical constraint: an axon must pass close to the dendrites that are near other neurons it contacts. The topographic organization of the mammalian cortex ensures that nearby neurons encode related information. Using neural network simulations, we demonstrate that ADO is a suitable mechanism for BIG learning. We model knowledge as associations between terms, concepts or indivisible units of thought via directed graphs. The simplest instantiation encodes each concept by single neurons. Results are then generalized to cell assemblies. The proposed mechanism results in learning real associations better than spurious co-occurrences, providing definitive cognitive advantages.
A New Model for a Carpool Matching Service
(Public Library of Science, 2015-06-30) Xia, Jizhe; Curtin, Kevin M.; Li, Weihong; Zhao, Yonglong
Carpooling is an effective means of reducing traffic. A carpool team shares a vehicle for their commute, which reduces the number of vehicles on the road during rush hour periods. Carpooling is officially sanctioned by most governments, and is supported by the construction of high-occupancy vehicle lanes. A number of carpooling services have been designed in order to match commuters into carpool teams, but it known that the determination of optimal carpool teams is a combinatorially complex problem, and therefore technological solutions are difficult to achieve. In this paper, a model for carpool matching services is proposed, and both optimal and heuristic approaches are tested to find solutions for that model. The results show that different solution approaches are preferred over different ranges of problem instances. Most importantly, it is demonstrated that a new formulation and associated solution procedures can permit the determination of optimal carpool teams and routes. An instantiation of the model is presented (using the street network of Guangzhou city, China) to demonstrate how carpool teams can be determined.
A Novel Application of Musculoskeletal Ultrasound Imaging
(Journal of Visualized Experiments, 2013-09) Eranki, Avinash; Cortes, Nelson; Ferenček3, Zrinka Gregurić; Siddhartha, Sikdar
Ultrasound is an attractive modality for imaging muscle and tendon motion during dynamic tasks and can provide a complementary methodological approach for biomechanical studies in a clinical or laboratory setting. Towards this goal, methods for quantification of muscle kinematics from ultrasound imagery are being developed based on image processing. The temporal resolution of these methods is typically not sufficient for highly dynamic tasks, such as drop-landing. We propose a new approach that utilizes a Doppler method for quantifying muscle kinematics. We have developed a novel vector tissue Doppler imaging (vTDI) technique that can be used to measure musculoskeletal contraction velocity, strain and strain rate with sub-millisecond temporal resolution during dynamic activities using ultrasound. The goal of this preliminary study was to investigate the repeatability and potential applicability of the vTDI technique in measuring musculoskeletal velocities during a drop-landing task, in healthy subjects. The vTDI measurements can be performed concurrently with other biomechanical techniques, such as 3D motion capture for joint kinematics and kinetics, electromyography for timing of muscle activation and force plates for ground reaction force. Integration of these complementary techniques could lead to a better understanding of dynamic muscle function and dysfunction underlying the pathogenesis and pathophysiology of musculoskeletal disorders.
A Stochastic Spatiotemporal Model of Rat Ventricular Myocyte Calcium Dynamics Demonstrated Necessary Features for Calcium Wave Propagation
(MDPI, 2021-11) Hoang-Trong, Tuan Minh; Ullah, Aman; Lederer, William Jonathan; Jafri, Mohsin Saleet
Calcium (Ca2+) plays a central role in the excitation and contraction of cardiac myocytes. Experi-ments have indicated that calcium release is stochastic and regulated locally suggesting the pos-sibility of spatially heterogeneous calcium levels in the cells. This spatial heterogeneity might be important in mediating different signaling pathways. During more than 50 years of computa-tional cell biology, the computational models have been advanced to incorporate more ionic cur-rents, going from deterministic models to stochastic models. While periodic increases in cyto-plasmic Ca2+ concentration drive cardiac contraction, aberrant Ca2+ release can underly cardiac arrhythmia. However, the study of the spatial role of calcium ions has been limited due to the computational expense of using a three-dimensional stochastic computational model. In this pa-per, we introduce a three-dimensional stochastic computational model for rat ventricular myo-cytes at the whole-cell level that incorporate detailed calcium dynamics, with (1) non-uniform re-lease site placement, (2) non-uniform membrane ionic currents and membrane buffers, (3) sto-chastic calcium-leak dynamics and (4) non-junctional or rogue ryanodine receptors. The model simulates spark-induced spark activation and spark-induced Ca2+ wave initiation and propaga-tion that occur under conditions of calcium overload at the closed-cell condition, but not when Ca2+ levels are normal. This is considered important since the presence of Ca2+ waves contribute to the activation of arrhythmogenic currents.
Abundance and Size of Gulf Shrimp in Louisiana's Coastal Estuaries following the Deepwater Horizon Oil Spill
(Public Library of Science, 2014-10-01) van der Ham, Joris L.; de Mutsert, Kim
The Deepwater Horizon oil spill impacted Louisiana's coastal estuaries physically, chemically, and biologically. To better understand the ecological consequences of this oil spill on Louisiana estuaries, we compared the abundance and size of two Gulf shrimp species (Farfantepeneus aztecus and Litopeneus setiferus) in heavily affected and relatively unaffected estuaries, before and after the oil spill. Two datasets were used to conduct this study: data on shrimp abundance and size before the spill were available from Louisiana Department of Wildlife and Fisheries (LDWF). Data on shrimp abundance and size from after the spill were independently collected by the authors and by LDWF. Using a Before-After-Control-Impact with Paired sampling (BACIP) design with monthly samples of two selected basins, we found brown shrimp to become more abundant and the mean size of white shrimp to become smaller. Using a BACIP with data on successive shrimp year-classes of multiple basins, we found both species to become more abundant in basins that were affected by the spill, while mean shrimp size either not change after the spill, or increased in both affected and unaffected basins. We conclude that following the oil spill abundances of both species increased within affected estuaries, whereas mean size may have been unaffected. We propose two factors that may have caused these results: 1) exposure to polycyclic aromatic hydrocarbons (PAHs) may have reduced the growth rate of shrimp, resulting in a delayed movement of shrimp to offshore habitats, and an increase of within-estuary shrimp abundance, and 2) fishing closures established immediately after the spill, may have resulted in decreased fishing effort and an increase in shrimp abundance. This study accentuates the complexities in determining ecological effects of oil spills, and the need of studies on the organismal level to reveal cause-and-effect relationships of such events.
“Advocacy” and “Activism” Are Not Dirty Words–How Activists Can Better Help Conservation Scientists
(Frontiers in Marine Science, 2016) Parsons, E. Christien Michael
Whether scientists should be advocates for conservation has been a matter of debate in the scientific community and literature (Brussard and Tull, 2007; Lackey, 2007; Noss, 2007; Chan, 2008; Nelson and Vucetich, 2009; Scott and Rachlow, 2010; Parsons, 2013; Rose and Parsons, 2015). Some are set against it, such as Lackey (2007), who considers that while scientists should be involved in the policy process, they should not show any preferences for conservation policies, nor even use value-laden terms in their work, such as good, healthy, or degradation. On the other side of the spectrum, Noss (2007) argues that everyone has opinions and values and, when it comes to making policy recommendations, who better to do so than scientists, who are closest to the facts?
Age-Independent Rise of Inflammatory Scores May Contribute to Accelerated Aging in Multi-Morbidity
(Impact Journals, LLC, 2015-02-10) Stepanova, Maria; Rodriguez, Edgar; Birerdinc, Aybike; Baranova, Ancha
Aging is associated with an increase in a chronic, low-grade inflammation. This phenomenon, termed “inflammaging” is also a risk factor for both morbidity and mortality in the elderly. Frequent co-occurrence of chronic diseases, known as multi-morbidity, may be explained by interconnected pathophysiology of these conditions, most of which depend on its inflammatory component. Here we present an analysis of the U.S. National Health and Nutrition Examination Survey data collected between 1999 and 2008, for the presence, and the number, of chronic diseases along with HDL-cholesterol, C-reactive protein, white blood cell count, lymphocyte percent, monocyte percent, segmented neutrophils percent, eosinophils percent, basophils percent, and glycohemoglobin levels. Importantly, even after adjustment for age and BMI, many inflammatory markers continued to be associated to multi-morbidity. C-reactive protein (CRP) levels and Glasgow Prognostic Score (GPS) were most dramatically increased in parallel with an accumulation of chronic diseases, and may be utilized as multi-morbidity predictors. These observations point at background inflammation as direct, age-independent contributor to an accumulation of the disease burden. Our findings also suggest a possibility that systemic inflammation associated with chronic diseases may explain accelerated aging phenomenon previously observed among the patients with heavy disease burden.
Alveoli, teeth, and tooth loss: Understanding the homology of internal mandibular structures in mysticete cetaceans
(PLOS One, 2017) Peredo, Carlos Mauricio; Pyenson, Nicholas D.; Uhen, Mark D.; Marshall, Christopher D.
The evolution of filter feeding in baleen whales (Mysticeti) facilitated a wide range of ecological diversity and extreme gigantism. The innovation of filter feeding evolved in a shift from a mineralized upper and lower dentition in stem mysticetes to keratinous baleen plates that hang only from the roof of the mouth in extant species, which are all edentulous as adults. While all extant mysticetes are born with a mandible lacking a specialized feeding structure (i.e., baleen), the bony surface retains small foramina with elongated sulci that often merge together in what has been termed the alveolar gutter. Because mysticete embryos develop tooth buds that resorb in utero, these foramina have been interpreted as homologous to tooth alveoli in other mammals. Here, we test this homology by creating 3D models of the internal mandibular morphology from terrestrial artiodactyls and fossil and extant cetaceans, including stem cetaceans, odontocetes and mysticetes. We demonstrate that dorsal foramina on the mandible communicate with the mandibular canal via smaller canals, which we explain within the context of known mechanical models of bone resorption. We suggest that these dorsal foramina represent distinct branches of the inferior alveolar nerve (or artery), rather than alveoli homologous with those of other mammals. As a functional explanation, we propose that these branches provide sensation to the dorsal margin of the mandible to facilitate placement and occlusion of the baleen plates during filer feeding.
Alveoli, teeth, and tooth loss: Understanding the homology of internal mandibular structures in mysticete cetaceans
(PLoS ONE, 2017) Peredo, Carlos Mauricio; Pyenson, Nicholas D.; Uhen, Mark D.; Marshall, Christopher D.
The evolution of filter feeding in baleen whales (Mysticeti) facilitated a wide range of ecological diversity and extreme gigantism. The innovation of filter feeding evolved in a shift from a mineralized upper and lower dentition in stem mysticetes to keratinous baleen plates that hang only from the roof of the mouth in extant species, which are all edentulous as adults. While all extant mysticetes are born with a mandible lacking a specialized feeding structure (i.e., baleen), the bony surface retains small foramina with elongated sulci that often merge together in what has been termed the alveolar gutter. Because mysticete embryos develop tooth buds that resorb in utero, these foramina have been interpreted as homologous to tooth alveoli in other mammals. Here, we test this homology by creating 3D models of the internal mandibular morphology from terrestrial artiodactyls and fossil and extant cetaceans, including stem cetaceans, odontocetes and mysticetes. We demonstrate that dorsal foramina on the mandible communicate with the mandibular canal via smaller canals, which we explain within the context of known mechanical models of bone resorption. We suggest that these dorsal foramina represent distinct branches of the inferior alveolar nerve (or artery), rather than alveoli homologous with those of other mammals. As a functional explanation, we propose that these branches provide sensation to the dorsal margin of the mandible to facilitate placement and occlusion of the baleen plates during filer feeding.
An Evaluation Synthesis of US AIDS Drug Assistance Program Policy
(Scientific Research, 2013-06) Horneffer, Michael A.; Yang, Y. Tony
US Congress passed the CARE Act in 1990 in response to a dramatically growing need for resources to combat the AIDS epidemic. One of the programs contained in the Act was the AIDS Drug Assistance Program (ADAP), a federally-funded but state-maintained and managed program primarily concerned with providing medication for low-income HIV/AIDS patients. While ADAP programs across the country reached one-third of all patients in 2007, these programs are now in budgetary danger due to the economic recession, state budgetary constraints, the rising cost of healthcare generally, and longer life expectancies associated with current highly active antiretroviral therapy (HAART). This paper first evaluates the current state of ADAP, its strengths and weaknesses, and examines its sustainability in the short term if short-term measures are taken. Concluding that such measures would not lead to long-term sustainability, this paper then argues for a long-term solution to ADAP’s current problems, namely a national, centralized ADAP standard for budgetary and administrative matters. Such a program would increase the long-term sustainability and effectiveness of current ADAP programs by employing more efficient, standard policies and allowing larger, wholesale purchases of costly HAART medications. Moreover, a national policy would address the disparity that currently exists in ADAP programs today with regard to both minorities and those on the waiting lists for treatment. The institution of a national ADAP program would certainly face many political hurdles. Consequently, this paper also looks to a recent political dispute, the enactment of the Affordable Care Act (ACA), for guidance. Using the passage of the ACA as an example could light the path for passage of a national ADAP standard. Ultimately, this would lead to a more effective and sustainable program for HIV/AIDS patients in the United States.
An expanded nuclear phylogenomic PCR toolkit for Sapindales
(Wiley, 2016-12-07) Collins, Elizabeth S.; Gostel, Morgan R.; Weeks, Andrea
Premise of the study: We tested PCR amplification of 91 low‐copy nuclear gene loci in taxa from Sapindales using primers developed for Bursera simaruba (Burseraceae). Methods and Results: Cross‐amplification of these markers among 10 taxa tested was related to their phylogenetic distance from B. simaruba. On average, each Sapindalean taxon yielded product for 53 gene regions (range: 16–90). Arabidopsis thaliana (Brassicales), by contrast, yielded product for two. Single representatives of Anacardiaceae and Rutacaeae yielded 34 and 26 products, respectively. Twenty‐six primer pairs worked for all Burseraceae species tested if highly divergent Aucoumea klaineana is excluded, and eight of these amplified product in every Sapindalean taxon. Conclusions: Our study demonstrates that customized primers for Bursera can amplify product in a range of Sapindalean taxa. This collection of primer pairs, therefore, is a valuable addition to the toolkit for nuclear phylogenomic analyses of Sapindales and warrants further investigation.
An open repository for single-cell reconstructions of the brain forest
(Scientific Data, 2018-02) Akram, Masood A.; Nanda, Sumit; Maraver, Patricia; Armañanzas, Rubén; Ascoli, Giorgio A.
NeuroMorpho.Org was launched in 2006 to provide unhindered access to any and all digital tracings of neuronal morphology that researchers were willing to share freely upon request. Today this database is the largest public inventory of cellular reconstructions in neuroscience with a content of over 80,000 neurons and glia from a representative diversity of animal species, anatomical regions, and experimental methods. Datasets continuously contributed by hundreds of laboratories worldwide are centrally curated, converted into a common non-proprietary format, morphometrically quantified, and annotated with comprehensive metadata. Users download digital reconstructions for a variety of scientific applications including visualization, classification, analysis, and simulations. With more than 1,000 peer-reviewed publications describing data stored in or utilizing data retrieved from NeuroMorpho.Org, this ever-growing repository can already be considered a mature resource for neuroscience.
An unshielded radio-frequency atomic magnetometer with sub-femtoTesla sensitivity
(AIP Publishing LLC, 2014-12-31) Keder, David A.; Prescott, David W.; Conovaloff, Adam W.; Sauer, Karen L.
We demonstrate a radio-frequency potassium-vapor magnetometer operating with sensitivities of 0.3 fT/√Hz at 0.5 MHz and 0.9 fT/ √Hz at 1.31 MHz in the absence of radio-frequency and mu-metal or magnetic shielding. The use of spatially separated magnetometers, two voxels within the same cell, permits for the subtraction of common mode noise and the retention of a gradient signal, as from a local source. At 0.5 MHz the common mode noise was white and measured to be 3.4 fT/ √Hz; upon subtraction the noise returned to the values observed when the magnetometer was shielded. At 1.31 MHz, the common mode noise was from a nearby radio station and was reduced by a factor of 33 upon subtraction, limited only by the radio signal picked up by receiver electronics. Potential applications include in-the-field low-field magnetic resonance, such as the use of nuclear quadrupole resonance for the detection of explosives.
Anthropometrics, Physical Performance, and Injury Characteristics of Youth American Football
(Sage, 2016-08-18) Caswell, Shane V.; Ausborn, Ashley; Guoqing, Diao; Johnson, David C.; Johnson, Timothy S.; Atkins, Rickie; Ambegaonkar, Jatin P.; Cortes, Nelson
Background: Prior research has described the anthropometric and physical performance characteristics of professional, collegiate, and high school American football players. Yet, little research has described these factors in American youth football and their potential relationship with injury. Purpose: To characterize anthropometric and physical performance measures, describe the epidemiology of injury, and examine the association of physical performance measures with injury among children participating within age-based divisions of a large metropolitan American youth football league. Study Design: Case-control study; Level of evidence, 3. Methods: Demographic, anthropometric, and physical performance characteristics and injuries of 819 male children were collected over a 2-year period (2011-2012). Injury data were collected by the league athletic trainer (AT) and coaches. Descriptive analysis of demographic, anthropometric, and physical performance measures (40-yard sprint, pro-agility, push-ups, and vertical jump) were conducted. Incidence rates were computed for all reported injuries; rates were calculated as the number of injuries per 1000 athlete-exposures (AEs). Multinomial logistic regression was used to identify whether the categories of no injury, no-time-loss (NTL) injury, and time-loss (TL) injury were associated with physical performance measures. Results: Of the 819 original participants, 760 (92.8%) completed preseason anthropometric measures (mean ± SD: age, 11.8 ± 1.2 years; height, 157.4 ± 10.7 cm; weight, 48.7 ± 13.3 kg; experience, 2.0 ± 1.8 years); 640 (78.1%) players completed physical performance measures. The mean (±SD) 40-yard sprint and pro-agility measures of the players were 6.5 ± 0.6 and 5.7 ± 0.5 seconds, respectively; the number of push-ups and maximal vertical jump height were 16.5 ± 9.3 repetitions and 42.3 ± 8.4 cm, respectively. Players assigned to different teams within age divisions demonstrated no differences in anthropometric measures; 40-yard dash and pro-agility times differed significantly (P < .05) between players assigned to different teams. A total of 261 NTL and TL injuries were reported during 35,957 AEs (games: 22%, n = 7982 AEs; practices: 78%, n = 27,975 AEs). The overall incidence rate was 7.26 per 1000 AEs (95% CI, 6.37-8.14). Physical performance measures did not predict NTL or TL injuries (P > .05). Conclusion: No practically meaningful differences existed in anthropometric or physical performance measures between teams within age-based levels of play. Findings suggest that age-only criterion for player groupings can evenly match in terms of physical performance.
Assessing recent warming using instrumentally homogeneous sea surface temperature records
(Scientific Advances, 2017) Hausfather, Zeke; Cowtan, Kevin; Clarke, David C.; Jacobs, Peter H; Richardson, Mark; Rohde, Robert
Sea surface temperature (SST) records are subject to potential biases due to changing instrumentation and measurement practices. Significant differences exist between commonly used composite SST reconstructions from the National Oceanic and Atmospheric Administration’s Extended Reconstruction Sea Surface Temperature (ERSST), the Hadley Centre SST data set (HadSST3), and the Japanese Meteorological Agency’s Centennial Observation-Based Estimates of SSTs (COBE-SST) from 2003 to the present. The update from ERSST version 3b to version 4 resulted in an increase in the operational SST trend estimate during the last 19 years from 0.07° to 0.12°C per decade, indicating a higher rate of warming in recent years. We show that ERSST version 4 trends generally agree with largely independent, near-global, and instrumentally homogeneous SST measurements from floating buoys, Argo floats, and radiometer-based satellite measurements that have been developed and deployed during the past two decades. We find a large cooling bias in ERSST version 3b and smaller but significant cooling biases in HadSST3 and COBE-SST from 2003 to the present, with respect to most series examined. These results suggest that reported rates of SST warming in recent years have been underestimated in these three data sets.
Assessing the methods needed for improved dengue mapping: a SWOT analysis
(African Field Epidemiology Network, 2014-04-16) Attaway, David Frost; Jacobsen, Kathryn H.; Falconer, Allan; Manca, Germana; Waters, Nigel M.
Introduction: Dengue fever, a mosquito-borne viral infection, is a growing threat to human health in tropical and subtropical areas worldwide. There is a demand from public officials for maps that capture the current distribution of dengue and maps that analyze risk factors to predict the future burden of disease. Methods: To identify relevant articles, we searched Google Scholar, PubMed, BioMed Central, and WHOLIS (World Health Organization Library Database) for published articles with a specific set of dengue criteria between January 2002 and July 2013. Results: After evaluating the currently available dengue models, we identified four key barriers to the creation of high-quality dengue maps: (1) data limitations related to the expense of diagnosing and reporting dengue cases in places where health information systems are underdeveloped; (2) issues related to the use of socioeconomic proxies in places with limited dengue incidence data; (3) mosquito ranges which may be changing as a result of climate changes; and (4) the challenges of mapping dengue events at a variety of scales. Conclusion: An ideal dengue map will present endemic and epidemic dengue information from both rural and urban areas. Overcoming the current barriers requires expanded collaboration and data sharing by geographers, epidemiologists, and entomologists. Enhanced mapping techniques would allow for improved visualizations of dengue rates and risks.

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