Years In Length Research Articles

Cyclic formation of zokor mounds promotes plant diversity and renews plant communities in alpine meadows on the Tibetan Plateau

Disturbance regimes are changing rapidly, along with the generation of patchy habitats, and the consequences of such changes for ecosystems will be profound. Plateau zokor mounds are a common natural disturbance on the Tibetan Plateau, and this disturbance leads to bare patches, and catalyse new paradigms of plant community dynamics in alpine ecosystems. We investigated, over 6 consecutive years, the dynamic changes of new zokor mounds, the effects of different zokor mound densities on plant diversity in alpine meadows at the spatial scale, and successional shifts in plant community on the bare mound patches at the temporal scale. The results showed that as the mound density increased, the species diversity and biomass of the plant communities (within mound-free regions between the mounds) significantly increased. Zokor mounds representing different successional stages comprise a mosaic and together constitute the alpine meadow. The cycle of plant succession on the bare mounds is about 6 years in length. The pioneer species were mainly rhizomatous grasses and broadleaf forbs. As succession progressed, the dominant species differed among the different mound patches. However, at the end of succession, the dominant species were grasses, and the species compositions were similar in the communities. The plant succession on the bare mound patches of the alpine meadow is a developmental process from founder-controlled to dominance-controlled communities. The coupling between patch-to-patch mosaic on different phases and year-to-year succession on bare mound patches is very important for species coexistence and promotes alpine meadow renewal.

Measuring sexual relationship power equity among young women and young men South Africa: Implications for gender-transformative programming.

IntroductionMeasures used to assess equitable relationship dynamics, including the sexual relationship power scale (SRPS) have previously been associated with lower HIV-risk among young women, and reduced perpetration of intimate partner violence among men. However, few studies describe how the SRPS has been adapted and validated for use within global youth sexual health studies. We examined gender-specific psychometric properties, reliability, and validity of a SRPS used within a South African youth-engaged cohort study.MethodsYoung men and women (16–24 years) enrolled in community-based cohorts in Durban and Soweto (2014–2016) reporting a primary partner at 6-month follow-up completed a 13-item (strongly agree/agree/disagree/strongly disagree) South African adaptation of Pulerwitz’s SRPS (range 13–52, higher scores indicating greater sexual relationship power [SRP] equity). SRPS modifications were made using gender-specific exploratory factor analyses (EFAs), removing items with factor loadings <0.3. Cronbach alphas were conducted for full and modified scales by gender. Using modified scales, unadjusted and adjusted regression models examined associations between 1. relevant socio-demographic and relationship determinants and SRP equity, and 2. SRP equity and sexual relationship related outcomes. All models adjusted for education, age, site, and current employment.Results235 sexually-active youth (66% women, median age = 20) were included. Mean scores across all 13 scale items were 2.71 (SD 0.30) for women and 2.70 (SD 0.4) for men. Scale Cronbach’s alphas were 0.63 for women and 0.64 for men. EFAs resulted in two gender-specific single-factor SRPS. Modified SRPS Cronbach alphas increased to 0.67 for women (8-items) and 0.70 for men (9-items). After adjusting for age, site and current employment, higher education remained associated with SRP equity across genders. In adjusted models, correlates of SRP equity included primary partnerships that were age-similar (<5 years older) and <2 years in length for women and living in Soweto and younger age for men. Greater SRP equity among women was also independently associated with no recent partner violence.ConclusionsResults highlight important gender differences in SRP equity measures and associations, highlighting the critically need for future research to examine gendered constructions of SRP equity in order to accurately develop, validate and use appropriate measures within quantitative surveys.

Combined Residency Programs in Emergency Medicine.

There are currently 5 combined residencies in emergency medicine (EM), namely EM/pediatrics, EM/internal medicine, EM/internal medicine/critical care, EM/family medicine and EM/anesthesiology. These combined programs vary from 5-6years in length. Like categorical programs, the decision to enter a 5- or 6-year program should be an informed and comprehensive decision. We describe the history and current status of the combined EM programs, discuss the process of applying to a combined EM program, describe the life of combined EM residents, and explore common career opportunities available to combined EM program graduates.

Two Family Interventions to Reduce BMI in Low-Income Urban Youth: A Randomized Trial.

Our primary aim was to evaluate the effects of 2 family-based obesity management interventions compared with a control group on BMI in low-income adolescents with overweight or obesity. In this randomized clinical trial, 360 urban-residing youth and a parent were randomly assigned to 1 of 2 behaviorally distinct family interventions or an education-only control group. Eligible children were entering the sixth grade with a BMI ≥85th percentile. Interventions were 3 years in length; data were collected annually for 3 years. Effects of the interventions on BMI slope (primary outcome) over 3 years and a set of secondary outcomes were assessed. Participants were primarily African American (77%), had a family income of <25 000 per year, and obese at enrollment (68%). BMI increased over time in all study groups, with group increases ranging from 0.95 to 1.08. In an intent-to-treat analysis, no significant differences were found in adjusted BMI slopes between either of the family-based interventions and the control group (P = .35). No differences were found between the experimental and control groups on secondary outcomes of diet, physical activity, sleep, perceived stress, or cardiometabolic factors. No evidence of effect modification of the study arms by sex, race and/or ethnicity, household income, baseline levels of child and parent obesity, or exposure to a school fitness program were found. In this low-income, adolescent population, neither of the family-based interventions improved BMI or health-related secondary outcomes. Future interventions should more fully address poverty and other social issues contributing to childhood obesity.

Tree-Ring Reconstructions of Streamflow for the Tennessee Valley

This study reports the preliminary results from a statistical screening of tree-ring width records from the International Tree-Ring Data Bank (ITRDB), to evaluate the strength of the hydrological signal, in dendrochronological records from the Tennessee Valley. We used United States Geological Survey (USGS) streamflow data from 11 gages, within the Tennessee Valley, and regional tree-ring chronologies, to analyze the dendroclimatic potential of the region, and create seasonal flow reconstructions. Prescreening methods included correlation, date, and temporal stability analysis of predictors to ensure practical and reliable reconstructions. Seasonal correlation analysis revealed that large numbers of regional tree-ring chronologies were significantly correlated (p ≤ 0.05) with the May–June–July streamflow. Stepwise linear regression was used to create the May–June–July streamflow reconstructions. Ten of the 12 streamflow stations were considered statistically skillful (R2 ≥ 0.40). Skillful reconstructions ranged from 208 to 301 years in length, and were statistically validated using leave-one-out cross validation, the sign test, and a comparison of the distribution of low flow years. The long-term streamflow variability was analyzed for the Nolichucky, Nantahala, Emory, and South Fork (SF) Holston stations. The reconstructions revealed that while most of the Western United States (U.S.). was experiencing some of its highest flow years during the early 1900s, the Tennessee Valley region was experiencing a very low flow. Results revealed the potential benefit of using tree-ring chronologies to reconstruct hydrological variables in the Southeastern U.S., by demonstrating the ability of proxy-based reconstructions to provide useful data beyond the instrumental record.

Atmosphere oxygen cycling through the Proterozoic and Phanerozoic

Variations in atmosphere oxygen and ocean sulfate concentrations through time are regarded as important controls on the cycles of sediment-hosted and volcanic-hosted ore deposits. However, estimates of atmosphere oxygen in the Proterozoic have been frustrated by the lack of a direct measurement method and conflicting evidence from various proposed geochemical proxies. Studies in the 1970s to 1990s suggested a relatively oxygenated atmosphere (> 3 wt% O2) in the Proterozoic. However, since the late 1990s, new proxies and modelling have suggested very much lower levels of oxygen (< 0.02 wt% O2). Focusing on redox-sensitive trace elements, here we combine a dataset of over 3000 LA-ICP-MS trace-element analyses on sedimentary pyrite, standardised against Berner’s Phanerozoic O2 modelling and direct measurement of oxygen concentrations in fluid inclusions in sedimentary halite, to develop the first detailed estimate for atmosphere O2 concentration and secular variation from 2200 Ma to the present. The estimates suggest dynamic cycles of atmosphere oxygen that increased in frequency through time. There were possibly three first-order cycles in the Proterozoic varying from 400 to 600 million years in length and a further five first-order cycles in the Phanerozoic from 60 to 120 million years in length. Our estimates of oxygen concentration are at odds with most previous estimates. We suggest, rather than very low atmosphere oxygen in the Proterozoic, the mean concentration was about 7 wt%, rising to a mean of about 10 wt% in the Phanerozoic, but with significant cyclic variation of up to a maximum concentration of possibly over 30 wt%. We observe that the proposed oxygen cycles correlate with biodiversity cycles and to the timing of major stratiform base-metal deposits in sedimentary basins. For example, minima in atmosphere oxygenation correlate with mass extinction events and stratiform Zn–Pb–Ag deposits, whereas maxima in oxygenation correlate with major evolutionary events, global periods of evaporite formation and the timing of stratiform copper deposits.

Influence of initial ocean conditions on temperature and precipitation in a coupled climate model's solution

Abstract. This paper describes results of an experiment that perturbed the initial conditions for the ocean's temperature field of the Community Earth System Model (CESM) with a well defined design. The resulting 30-member ensemble of CESM simulations, each of 10 years in length, is used to create an emulator (a nonlinear regression relating the initial conditions to various outcomes) from the simulators. Through the use of the emulator to expand the output distribution space, we estimate the spatial uncertainties at 10 years for surface air temperature, 25 m ocean temperature, precipitation, and rain. Outside the tropics, basin averages for the uncertainty in the ocean temperature field range between 0.48 ∘C (Indian Ocean) and 0.87 ∘C (North Pacific) (2 standard deviation). The tropical Pacific uncertainty is the largest due to different phasings of the ENSO signal. Over land areas, the regional temperature uncertainty varies from 1.03 ∘C (South America) to 10.82 ∘C (Europe) (2 standard deviation). Similarly, the regional average uncertainty in precipitation varies from 0.001 cm day−1 over Antarctica to 0.163 cm day−1 over Australia with a global average of 0.075 cm day−1. In general, both temperature and precipitation uncertainties are larger over land than over the ocean. A maximum covariance analysis is used to examine how ocean temperatures affect both surface air temperatures and precipitation over land. The analysis shows that the tropical Pacific influences the temperature over North America, but the North America surface temperature is also moderated by the state of the North Pacific outside the tropics. It also indicates which regions show a high degree of variance between the simulations in the ensemble and are, therefore, less predictable. The calculated uncertainties are also compared to an estimate of internal variability within CESM. Finally, the importance of feedback processes on the solution of the simulation over the 10 years of the experiment is quantified. These estimates of uncertainty do not take into consideration the anthropogenic effect on warming of the atmosphere and ocean.

Royal College of Physicians Medical Training Initiative: making the difference

The Medical Training Initiative (MTI) scheme supports international medical graduates (IMGs) seeking short-term training posts in the UK of up to 2 years in length through international partnerships, locating of well-qualified trainees and often linking with UK trust training posts. By facilitating General Medical Council (GMC) registration, sponsoring Tier 5 visas and providing additional benefits and pastoral support, the Royal College of Physicians’ (RCP's) MTI scheme aims to bring the highest standards of UK medical training to a diverse global group and make a significant impact on the development of medical training, knowledge and skills in the partner countries that we engage with. In order to deliver the highest standard of UK training posts to IMG …

GUARANTEED STRENGTH OF PIPES WITH TRANSVERSE CRACKS UNDER STRESS

Background One of the priority tasks to ensure reliable operation of main gas pipelines is to identify defects in pipe walls. Modern intratubal flaw detectors provide reliable finding of defects such as «transverse cracks» and «transverse cracks zone» at a level of at least 20 % of the pipe wall thickness. This circumstance implies that pipes with these defects types (with a depth of less than 20 %) remain in operation, but they can lead to accidental failures of gas pipelines. In this regard, there is a need to assess the cracks risk in terms of brittle fracture, as the most unpredictable and rapid process. Aims and Objectives Based on the numerical calculation of the stress intensity factor, to determine the level of longitudinal stresses, which guarantees the strength of the pipeline section with transverse cracks under stress. Methods A stretchable strip of infinite length with a transverse crack is taken as the computational model. To account for the viscous component in the fracture of the pipe wall, the problem was considered in the elastoplastic formulation, with the calculation of the Cherepanov-Rice integral. Results In the absence of data, the following values are used to estimate the growth rate of developing defects: the growth rate of the stress-corrosion defect: 1.0 mm / year in depth, 4.0 mm / year in length and width. A theoretically undetected crack 3.14 mm deep over 2 years of operation (the frequency of in-line inspection in areas with identified stress-corrosion cracking defects) may increase to a depth of 5.14 mm and actually lead to destruction over a given period of time. The presented calculation results show the need to determine the pipe steel ductility characteristics: fracture toughness, elastoplastic fracture toughness, and also allow to determine the longitudinal stresses level for guaranteed strength of a section of the main gas pipeline.

Augmenting limited background monitoring data for improved performance in land use regression modelling: Using support vector regression and mobile monitoring

Land Use Regression (LUR) models was developed using fixed site and mobile station data in Dublin Ireland. The uncertainty associated with short term, mobile station data was accounted for using a weighted function, considering the differences in record duration of data across the study. A systematic buffer distance decay curve-based approach was also considered in this study to identify appropriate predictors and their associated buffer distance. The analysis was performed in Dublin city for fine particulate matter (PM2.5) where 10 fixed monitoring stations data were available, with average daily concentration data records of 1–7 years in length. 105 mobile station data were also collected at several locations in the city for durations of 12 h to 3 days. The performance of a developed multiple linear regression based LUR model was evaluated by using the leave-one-out-cross-validation procedure. The model explained variances (R2) of the LUR model were found to be 0.219 for winter and 0.688 for summer months. One of the primary reasons for poor performance of the LUR model was that the relationship between the predictors and the mean PM2.5 concentration were found to be non-linear which cannot be modelled by using multiple linear regression approach. To address this, a weighted support vector regression (WSVR) approach was also considered that can account for non-linearity while developing the LUR model. The model performance in terms of R2 was found to improve to 0.912 for winter and 0.916 for summer using this method. The developed WSVR model can be used to predict PM2.5 concentration at any ungauged locations in the study area with considerable accuracy, which can be the basis for future epidemiological studies.

The Welfare Effects of Long-Term Health Insurance Contracts

Reclassification risk is a major concern in health insurance where contracts are typically one year in length but health shocks often persist for much longer. We use rich individual-level medical information from the Utah all-payer claims database to empirically study one possible solution: long-term insurance contracts. We characterize optimal long-term contracts with one-sided commitment theoretically, derive the contracts that are optimal for consumers in Utah, and assess the welfare level that a full implementation of these contracts could achieve relative to several key benchmarks. We find that dynamic contracts perform very well for the majority of the population, for example, eliminating over 94% of the welfare loss from reclassification risk for individuals who arrive on the market at age 25 in good health. However, dynamic contracts instead provide very little benefit to the worst pre-age-25 health risks. Their value is also substantially lower for consumers whose income growth with age is relatively high. With pre-age-25 insurance in place, consumers with flat net income prefer dynamic contracts to an ACA-like environment, but consumers with steeper income profiles prefer the ACA-like environment. Overall, we show that there are scenarios in which dynamic contracts can provide substantial welfare benefits, but that complementary policies are crucial for unlocking these benefits.

Extreme reduction in nutritional value of a key forage fish during the Pacific marine heatwave of 2014-2016

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 613:171-182 (2019) - DOI: https://doi.org/10.3354/meps12891 Extreme reduction in nutritional value of a key forage fish during the Pacific marine heatwave of 2014-2016 Vanessa R. von Biela1,*, Mayumi L. Arimitsu2, John F. Piatt1, Brielle Heflin2, Sarah K. Schoen1, Jannelle L. Trowbridge1,3, Chelsea M. Clawson1,4 1US Geological Survey, Alaska Science Center, 4210 University Drive, Anchorage, Alaska 99508, USA 2US Geological Survey, Alaska Science Center, 250 Egan Dr., Juneau, Alaska 99801, USA 3University of Alaska Anchorage, Alaska Native Science & Engineering Program, 3211 Providence Drive, Anchorage, Alaska 99508, USA 4Alaska Sea Grant Marine Advisory Program, 1007 W 3rd Avenue, Suite 100, Anchorage, Alaska 99501, USA *Corresponding author: vvonbiela@usgs.gov ABSTRACT: Pacific sand lance Ammodytes personatus are a key forage fish in the North Pacific for many species of salmon, groundfish, seabirds, and marine mammals and have historically been important to predators in relatively warm years. However, extreme declines in the nutritional value of sand lance in Prince William Sound, Alaska, USA, during 2012-2016 indicate that energy transfer from lower trophic levels to predators via sand lance may have been disrupted during the North Pacific marine heatwave in 2015 and 2016. Nutritional value (length, energy density, and whole-body energy) was measured in age-0 and age-1 sand lance collected during July in cool (2012-2013) and increasingly warm (2014-2016) years. The value of age-0 fish was relatively stable, with only minor differences among years for length and whole-body energy. By contrast, the value of age-1 fish significantly declined in 2015, and by 2016 they were 38% shorter and 13% lower in energy density compared to cooler years. This contributed to significant declines in whole-body energy of 44% in 2015 and 89% in 2016 compared to cooler years (2012-2014). The 2015 sand lance cohort experienced little growth or lipid accumulation from July 2015 at age-0 to July 2016 at age-1. This effective disruption of energy flow through pelagic food webs probably contributed to population declines and/or breeding failures observed among several predators in the Gulf of Alaska and suggests that tipping points were reached during the heatwave. KEY WORDS: Pacific sand lance · Ammodytes personatus · ‘The Blob’ · Gulf of Alaska · Body condition · Energy density Full text in pdf format PreviousNextCite this article as: von Biela VR, Arimitsu ML, Piatt JF, Heflin B, Schoen SK Trowbridge JL, Clawson CM (2019) Extreme reduction in nutritional value of a key forage fish during the Pacific marine heatwave of 2014-2016. Mar Ecol Prog Ser 613:171-182. https://doi.org/10.3354/meps12891 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 613. Online publication date: March 21, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Altimeter-era emergence of the patterns of forced sea-level rise in climate models and implications for the future

The satellite altimeter record has provided an unprecedented database for understanding sea-level rise and has recently reached a major milestone at 25 years in length. A challenge now exists in understanding its broader significance and its consequences for sea-level rise in the coming decades and beyond. A key question is whether the pattern of altimeter-era change is representative of longer-term trends driven by anthropogenic forcing. In this work, two multimember climate ensembles, the Community Earth System Model (CESM) and the Earth System Model Version 2M (ESM2M), are used to estimate patterns of forced change [also known as the forced response (FR)] and their magnitudes relative to internal variability. It is found that the spatial patterns of 1993-2018 trends in the ensembles correlate significantly with the contemporaneous FRs (0.55 ± 0.10 in the CESM and 0.61 ± 0.09 in the ESM2M) and the 1950-2100 FRs (0.43 ± 0.10 in the CESM and 0.51 ± 0.11 in the ESM2M). Unforced runs for each model show such correlations to be extremely unlikely to have arisen by chance, indicating an emergence of both the altimeter-era and long-term FRs and suggesting a similar emergence in nature. Projected patterns of the FR over the coming decades resemble those simulated during the altimeter era, suggesting a continuation of the forced pattern of change in nature in the coming decades. Notably, elevated rates of rise are projected to continue in regions that are susceptible to tropical cyclones, exacerbating associated impacts in a warming climate.

Teacher training in GIS: what is needed for long-term success?

This article explores teacher training in geographic information system (GIS) and hopes to uncover the necessary elements required for long-term and sustained use of GIS in the K-12 classroom. A variety of models have been proposed for successful GIS professional development including long-term teacher training lasting up to a year in length. Our study takes an additional step by following up with teachers over a full year after they have completed training to determine if they are continuing to teach with GIS and if so, how. We find there remains a disconnect between providing GIS teacher professional development and actually seeing long-term classroom implementation. We offer three recommendations for transformation in teacher practice: pre-service teacher geography and GIS intervention, continuous follow-up and coaching, and including GIS in Academic Standards.

An Empirical Mode-Spatial Model for Environmental Data Imputation

Complete and accurate data are necessary for analyzing and understanding trends in time-series datasets; however, many of the available time-series datasets have gaps that affect the analysis, especially in the earth sciences. As most available data have missing values, researchers use various interpolation methods or ad hoc approaches to data imputation. Since the analysis based on inaccurate data can lead to inaccurate conclusions, more accurate data imputation methods can provide accurate analysis. We present a spatial-temporal data imputation method using Empirical Mode Decomposition (EMD) based on spatial correlations. We call this method EMD-spatial data imputation or EMD-SDI. Though this method is applicable to other time-series data sets, here we demonstrate the method using temperature data. The EMD algorithm decomposes data into periodic components called intrinsic mode functions (IMF) and exactly reconstructs the original signal by summing these IMFs. EMD-SDI initially decomposes the data from the target station and other stations in the region into IMFs. EMD-SDI evaluates each IMF from the target station in turn and selects the IMF from other stations in the region with periodic behavior most correlated to target IMF. EMD-SDI then replaces a section of missing data in the target station IMF with the section from the most closely correlated IMF from the regional stations. We found that EMD-SDI selects the IMFs used for reconstruction from different stations throughout the region, not necessarily the station closest in the geographic sense. EMD-SDI accurately filled data gaps from 3 months to 5 years in length in our tests and favorably compares to a simple temporal method. EMD-SDI leverages regional correlation and the fact that different stations can be subject to different periodic behaviors. In addition to data imputation, the EMD-SDI method provides IMFs that can be used to better understand regional correlations and processes.

Plasmodiophora brassicae resting spore dynamics in clubroot resistant canola (Brassica napus) cropping systems

The soilborne pathogen Plasmodiophora brassicae, causal agent of clubroot of canola (Brassica napus), is difficult to manage due to the longevity of its resting spores, ability to produce large amounts of inoculum, and the lack of effective fungicides. The cropping of clubroot resistant (CR) canola cultivars is one of the few effective strategies for clubroot management. This study evaluated the impact of the cultivation of CR canola on P. brassicae resting spore concentrations in commercial cropping systems in Alberta, Canada. Soil was sampled pre‐seeding and post‐harvest at multiple georeferenced locations within 17 P. brassicae‐infested fields over periods of up to 4 years in length. Resting spore concentrations were measured by quantitative PCR analysis, with a subset of samples also evaluated in greenhouse bioassays with a susceptible host. The cultivation of CR canola in soil with quantifiable levels of P. brassicae DNA resulted in increased inoculum loads. There was a notable lag in the release of inoculum after harvest, and quantifiable P. brassicae inoculum peaked in the year following cultivation of CR canola. Rotations that included a ≥2‐year break from P. brassicae hosts resulted in significant declines in soil resting spore concentrations. A strong positive relationship was found between the bioassays and qPCR‐based estimates of soil infestation. Results suggest that CR canola should not be used to reduce soil inoculum loads, and crop rotations in P. brassicae infested fields should include breaks of at least 2 years away from B. napus, otherwise the risk of selecting for virulent pathotypes may increase.

Pediatric Emergency Medicine Simulation Curriculum: Cardiac Tamponade.

Cardiac tamponade is an uncommon presentation to the pediatric emergency department and requires early recognition and emergent intervention. We developed this patient simulation case to simulate a low-frequency, high-acuity scenario for pediatric emergency medicine fellows and resident physicians in emergency medicine, pediatrics, and family medicine. We ran the case in a pediatric emergency department using a high-fidelity pediatric mannequin and equipment found in the clinical environment, including a bedside ultrasound machine. The case involved a 10-year-old patient with Hodgkin lymphoma who presented with fever, neutropenia, and shock and was found to have a pericardial effusion with tamponade after evaluation. The providers were expected to identify signs and symptoms of shock, as well as cardiac tamponade, and demonstrate appropriate emergent evaluation and management. Required personnel included a simulation technician, instructors, and a nurse. Debriefing tools tailored specifically for this scenario were created to facilitate a formal debriefing and formative learner assessment at the end of the simulation. This case has been implemented with 10 pediatric emergency medicine fellows during two 3-year cycles of fellow education. Session feedback reflected a high level of satisfaction with the case and an increased awareness of bedside ultrasound in the identification of cardiac tamponade. This resource for teaching the critical components for diagnosing and managing unstable cardiac tamponade in the pediatric patient, including use of bedside ultrasound, was well received by pediatric emergency medicine fellows.

Systematic variation in evapotranspiration trends and drivers across the Northeastern United States

AbstractThe direction and magnitude of responses of evapotranspiration (ET) to climate change are important to understand, as ET represents a major water and energy flux from terrestrial ecosystems, with consequences that feed back to the climate system. We inferred multidecadal trends in water balance in 11 river basins (1940–2012) and eight smaller watersheds (with records ranging from 18 to 61 years in length) in the Northeastern United States. Trends in river basin actual ET (AET) varied across the region, with an apparent latitudinal pattern: AET increased in the cooler northern part of the region (Maine) but decreased in some warmer regions to the southwest (Pennsylvania–Ohio). Of the four small watersheds with records longer than 45 years, two fit this geographic pattern in AET trends. The differential effects of the warming climate on AET across the region may indicate different mechanisms of change in more‐ vs. less‐energy‐limited watersheds, even though annual precipitation greatly exceeds potential ET across the entire region. Correlations between AET and time series of temperature and precipitation also indicate differences in limiting factors for AET across the Northeastern U.S. climate gradient. At many sites across the climate gradient, water‐year AET correlated with summer precipitation, implying that water limitation is at least transiently important in some years, whereas correlations with temperature indices were more prominent in northern than southern sites within the region.

Long-term and regional perspectives on recent change in lacustrine diatom communities in the tropical Andes

Understanding and managing the responses of natural systems to climate change requires knowing whether recent changes in ecosystem structure and function are within the bounds of natural variation or whether the systems are entering new states that are unprecedented. Several recent studies of the fossil diatom record of the last ~ 150 years in Andean lakes have shown changes in diatom species composition that suggest changes in lake thermal structure in response to regional climate warming. Yet these paleolimnological records are only a few hundred years in length, so it is unclear whether the systems have entered new states, with potentially severe consequences for ecosystem structure and function, or whether current trends are within the natural variability of the systems. Here, we use a recently compiled diatom database from tropical South America to explore the regional distribution and ecological controls of selected planktic diatom taxa that are associated with warming and changes in the lake thermal structure. We also review published Andean stratigraphic records that span thousands of years to characterize the long-term dynamics of relevant planktic species in response to past climate change. The contemporary data show that many planktic taxa have broad latitudinal and elevational distributions. The distributions of several taxa are correlated with surface water temperature, but most also are correlated with pH and/or conductivity. A review of existing stratigraphic data from Andean lakes demonstrates that rapid changes in diatom abundance, including abrupt increases followed by decades to centuries of near extirpation, are a common mode of population variation for some planktic taxa. Yet the majority of these published paleolimnological investigations are of lakes that are larger and differ in nutrient status and conductivity from the small dilute systems where recent species shifts have been observed. We propose that assessing the resilience of contemporary diatom communities and, by inference, lake ecosystems is best done by generating new records from Andean lakes of varied size and chemistry that span a millennium or more and hence a broader spectrum of climate conditions, coupled with new ecological and biogeographic studies that build upon ongoing research programs in the tropical Andes. (Less)

The durability of oral diabetic medications: Time to A1c baseline and a review of common oral medications used by the primary care provider

Cost of generic medications has risen more in the past few years than any other time in history. While medical insurance covers much of these costs, health care professionals can better provide medications that have the longest duration of action when compared to placebo-treated controls. This will save health care costs and improve prescribing accuracy. Papers in PubMed were identified with keywords placebo. The study must be at least 2 years in length to evaluate the change in A1c over time. The primary endpoint was time to A1c neutrality (return of A1c to baseline at a maximum dose of single oral agent). A medication would be considered at neutrality if the 95% CI crossed baseline. Time to neutrality was averaged for each medication within the class and each summarized for class effect. Effective therapy for the DPP-4 and sulfonylurea classes of medications are 3-4 years as compared to a 5-year time to A1c neutrality for metformin usage. In comparison, the projected time to A1c neutrality was approximately 6-8 years for rosiglitazone and pioglitazone. While only a few studies have been published in the SGLT-2 class of medication, the time to A1c neutrality was also 6-8 years with Canagliflozin and full dosage of Empagliflozin. Metformin appears to have a 5-year duration of effect before the A1c returns to baseline. The sulfonylureas and DPP-4 inhibitors class of medications have one of the shortest durability which ranges between 3.3 to 4.4 years. In contrast, the SGLT-2 class of medication and the TZD class of medications has a projected time to A1c neutrality from 6-8 years. Diabetic duration of therapy as compared to placebo should be listed with those medications tested so the provider can choose wisely.