University of Alaska Anchorage

Abstract Recent research using repeat photography, long-term ecological monitoring and dendrochronology has documented shrub expansion in arctic, high-latitude and alpine tundra ecosystems. Here, we (1) synthesize these findings, (2) present a conceptual framework that identifies mechanisms and constraints on shrub increase, (3) explore causes, feedbacks and implications of the increased shrub cover in tundra ecosystems, and (4) address potential lines of investigation for future research. Satellite observations from around the circumpolar Arctic, showing increased productivity, measured as changes in ‘greenness’, have coincided with a general rise in high-latitude air temperatures and have been partly attributed to increases in shrub cover. Studies indicate that warming temperatures, changes in snow cover, altered disturbance regimes as a result of permafrost thaw, tundra fires, and anthropogenic activities or changes in herbivory intensity are all contributing to observed changes in shrub abundance. A large-scale increase in shrub cover will change the structure of tundra ecosystems and alter energy fluxes, regional climate, soil–atmosphere exchange of water, carbon and nutrients, and ecological interactions between species. In order to project future rates of shrub expansion and understand the feedbacks to ecosystem and climate processes, future research should investigate the species or trait-specific responses of shrubs to climate change including: (1) the temperature sensitivity of shrub growth, (2) factors controlling the recruitment of new individuals, and (3) the relative influence of the positive and negative feedbacks involved in shrub expansion.

A major challenge in predicting Earth's future climate state is to understand feedbacks that alter greenhouse-gas forcing. Here we synthesize field data from arctic Alaska, showing that terrestrial changes in summer albedo contribute substantially to recent high-latitude warming trends. Pronounced terrestrial summer warming in arctic Alaska correlates with a lengthening of the snow-free season that has increased atmospheric heating locally by about 3 watts per square meter per decade (similar in magnitude to the regional heating expected over multiple decades from a doubling of atmospheric CO2). The continuation of current trends in shrub and tree expansion could further amplify this atmospheric heating by two to seven times.

Research on gaze and eye contact was organized within the framework of Patterson's (1982) sequential functional model of nonverbal exchange. Studies were reviewed showing how gaze functions to (a) provide information, (b) regulate interaction, (c) express intimacy, (d) exercise social control, and (

At the close of the Fourth International Polar Year, we take stock of the ecological consequences of recent climate change in the Arctic, focusing on effects at population, community, and ecosystem scales. Despite the buffering effect of landscape heterogeneity, Arctic ecosystems and the trophic relationships that structure them have been severely perturbed. These rapid changes may be a bellwether of changes to come at lower latitudes and have the potential to affect ecosystem services related to natural resources, food production, climate regulation, and cultural integrity. We highlight areas of ecological research that deserve priority as the Arctic continues to warm.

A search for high-energy neutrinos interacting within the IceCube detector between 2010 and 2012 provided the first evidence for a high-energy neutrino flux of extraterrestrial origin. Results from an analysis using the same methods with a third year (2012-2013) of data from the complete IceCube detector are consistent with the previously reported astrophysical flux in the 100 TeV-PeV range at the level of 10(-8) GeV cm-2 s-1 sr-1 per flavor and reject a purely atmospheric explanation for the combined three-year data at 5.7σ. The data are consistent with expectations for equal fluxes of all three neutrino flavors and with isotropic arrival directions, suggesting either numerous or spatially extended sources. The three-year data set, with a live time of 988 days, contains a total of 37 neutrino candidate events with deposited energies ranging from 30 to 2000 TeV. The 2000-TeV event is the highest-energy neutrino interaction ever observed.

Understanding the sensitivity of tundra vegetation to climate warming is critical to forecasting future biodiversity and vegetation feedbacks to climate. In situ warming experiments accelerate climate change on a small scale to forecast responses of local plant communities. Limitations of this approach include the apparent site-specificity of results and uncertainty about the power of short-term studies to anticipate longer term change. We address these issues with a synthesis of 61 experimental warming studies, of up to 20 years duration, in tundra sites worldwide. The response of plant groups to warming often differed with ambient summer temperature, soil moisture and experimental duration. Shrubs increased with warming only where ambient temperature was high, whereas graminoids increased primarily in the coldest study sites. Linear increases in effect size over time were frequently observed. There was little indication of saturating or accelerating effects, as would be predicted if negative or positive vegetation feedbacks were common. These results indicate that tundra vegetation exhibits strong regional variation in response to warming, and that in vulnerable regions, cumulative effects of long-term warming on tundra vegetation - and associated ecosystem consequences - have the potential to be much greater than we have observed to date.

OBJECTIVE: Premature discontinuation from therapy is a widespread problem that impedes the delivery of otherwise effective psychological interventions. The most recent comprehensive review found an average dropout rate of 47% across 125 studies (Wierzbicki & Pekarik, 1993); however, given a number of changes in the field over the past 2 decades, an updated meta-analysis is needed to examine the current phenomenon of therapy dropout. METHOD: A series of meta-analyses and meta-regressions were conducted in order to identify the rate at which treatment dropout occurs and predictors of its occurrence. This review included 669 studies representing 83,834 clients. RESULTS: Averaging across studies using a random effects model, the weighted dropout rate was 19.7%, 95% CI [18.7%, 20.7%]. Further analyses, also using random effects models, indicated that the overall dropout rate was moderated by client diagnosis and age, provider experience level, setting for the intervention, definition of dropout, type of study (efficacy vs. effectiveness), and other design variables. Dropout was not moderated by orientation of therapy, whether treatment was provided in an individual or group format, and a number of client demographic variables. CONCLUSIONS: Although premature discontinuation is occurring at a lower rate than what was estimated 20 years ago (Wierzbicki & Pekarik, 1993), it is still a significant problem, with about 1 in every 5 clients dropping out of therapy. Special efforts should be made to decrease premature discontinuation, particularly with clients who are younger, have a personality or eating disorder diagnosis, and are seen by trainee clinicians.

Ratios of nitrogen (N) isotopes in leaves could elucidate underlying patterns of N cycling across ecological gradients. To better understand global-scale patterns of N cycling, we compiled data on foliar N isotope ratios (delta(15)N), foliar N concentrations, mycorrhizal type and climate for over 11,000 plants worldwide. Arbuscular mycorrhizal, ectomycorrhizal, and ericoid mycorrhizal plants were depleted in foliar delta(15)N by 2 per thousand, 3.2 per thousand, 5.9 per thousand, respectively, relative to nonmycorrhizal plants. Foliar delta(15)N increased with decreasing mean annual precipitation and with increasing mean annual temperature (MAT) across sites with MAT >or= -0.5 degrees C, but was invariant with MAT across sites with MAT < -0.5 degrees C. In independent landscape-level to regional-level studies, foliar delta(15)N increased with increasing N availability; at the global scale, foliar delta(15)N increased with increasing foliar N concentrations and decreasing foliar phosphorus (P) concentrations. Together, these results suggest that warm, dry ecosystems have the highest N availability, while plants with high N concentrations, on average, occupy sites with higher N availability than plants with low N concentrations. Global-scale comparisons of other components of the N cycle are still required for better mechanistic understanding of the determinants of variation in foliar delta(15)N and ultimately global patterns in N cycling.

We report on the observation of two neutrino-induced events which have an estimated deposited energy in the IceCube detector of $1.04\ifmmode\pm\else\textpm\fi{}0.16$ and $1.14\ifmmode\pm\else\textpm\fi{}0.17\text{ }\text{ }\mathrm{PeV}$, respectively, the highest neutrino energies observed so far. These events are consistent with fully contained particle showers induced by neutral-current ${\ensuremath{\nu}}_{e,\ensuremath{\mu},\ensuremath{\tau}}$ (${\overline{\ensuremath{\nu}}}_{e,\ensuremath{\mu},\ensuremath{\tau}}$) or charged-current ${\ensuremath{\nu}}_{e}$ (${\overline{\ensuremath{\nu}}}_{e}$) interactions within the IceCube detector. The events were discovered in a search for ultrahigh energy neutrinos using data corresponding to 615.9 days effective live time. The expected number of atmospheric background is $0.082\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{stat}{)}_{\ensuremath{-}0.057}^{+0.041}(\mathrm{syst})$. The probability of observing two or more candidate events under the atmospheric background-only hypothesis is $2.9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ ($2.8\ensuremath{\sigma}$) taking into account the uncertainty on the expected number of background events. These two events could be a first indication of an astrophysical neutrino flux; the moderate significance, however, does not permit a definitive conclusion at this time.

The IceCube Neutrino Observatory is a cubic-kilometer-scale high-energy neutrino detector built into the ice at the South Pole. Construction of IceCube, the largest neutrino detector built to date, was completed in 2011 and enabled the

The age, or residence time, of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways, and source of water in a single integrated measure. While there has been tremendous recent interest in residence time estimation to characterize watersheds, there are relatively few studies that have quantified residence time at the watershed scale, and fewer still that have extended those results beyond single catchments to larger landscape scales. We examined topographic controls on residence time for seven catchments (0.085–62.4 km 2 ) that represent diverse geologic and geomorphic conditions in the western Cascade Mountains of Oregon. Our primary objective was to determine the dominant physical controls on catchment‐scale water residence time and specifically test the hypothesis that residence time is related to the size of the basin. Residence times were estimated by simple convolution models that described the transfer of precipitation isotopic composition to the stream network. We found that base flow mean residence times for exponential distributions ranged from 0.8 to 3.3 years. Mean residence time showed no correlation to basin area (r 2 &lt; 0.01) but instead was correlated (r 2 = 0.91) to catchment terrain indices representing the flow path distance and flow path gradient to the stream network. These results illustrate that landscape organization (i.e., topography) rather than basin area controls catchment‐scale transport. Results from this study may provide a framework for describing scale‐invariant transport across climatic and geologic conditions, whereby the internal form and structure of the basin defines the first‐order control on base flow residence time.

This review paper examines thermal conditions (active layer and permafrost), internal composition (rock and ice components), kinematics and rheology of creeping perennially frozen slopes in cold mountain areas. The aim is to assemble current information about creep in permafrost and rock glaciers from diverse published sources into a single paper that will be useful in studies of the flow and deformation of subsurface ice and their surface manifestations not only on Earth, but also on Mars. Emphasis is placed on quantitative information from drilling, borehole measurements, geophysical soundings, photogrammetry, laboratory experiments, etc. It is evident that quantitative holistic treatment of permafrost creep and rock glaciers requires consideration of: (a) rock weathering, snow avalanches and rockfall, with grain-size sorting on scree slopes; (b) freezing processes and ice formation in scree at sub-zero temperatures containing abundant fine material as well as coarse-grained blocks; (c) coupled thermohydro-mechanical aspects of creep and failure processes in frozen rock debris; (d) kinematics of non-isotropic, heterogeneous and layered, ice-rich permafrost on slopes with long transport paths for coarse surface material from the headwall to the front and, in some cases, subsequent re-incorporation into an advancing rock glacier causing corresponding age inversion at depth; and (e) the dynamics of rock glaciers, which include spatial and temporal variations in velocity that are manifested in the ridges, furrows and other surface structures typical of rock glaciers, as well as their down-valley motion. Copyright © 2006 John Wiley & Sons, Ltd.

With a rigorous and comprehensive coverage, the second edition of Compliant Mechanisms: Design of Flexure Hinges provides practical answers to the design and analysis of devices that incorporate flexible hinges. Complex-shaped flexible-hinge mechanisms are generated from basic elastic segments by means of a bottom-up compliance (flexibility) approach. The same compliance method and the classical finite element analysis are utilized to study the quasi-static and dynamic performances of these compliant mechanisms. This book offers easy-to-use mathematical tools to investigate a wealth of flexible-hinge configurations and two- or three-dimensional compliant mechanism applications. FEATURES Introduces a bottom-up compliance-based approach to characterize the flexibility of new and existing flexible hinges of straight- and curvilinear-axis configurations Develops a consistent linear lumped-parameter compliance model to thoroughly describe the quasi-static and dynamic behavior of planar/spatial, serial/parallel flexible-hinge mechanisms Utilizes the finite element method to analyze the quasi-statics and dynamics of compliant mechanisms by means of straight- and curvilinear-axis flexible-hinge elements Covers miscellaneous topics such as stress concentration, yielding and related maximum load, precision of rotation of straight- and circular-axis flexible hinges, temperature effects on compliances, layered flexible hinges and piezoelectric actuation/sensing Offers multiple solved examples of flexible hinges and flexible-hinge mechanisms. This book should serve as a reference to students, researchers, academics and anyone interested to investigate precision flexible-hinge mechanisms by linear model-based methods in various areas of mechanical, aerospace or biomedical engineering, as well as in robotics and micro-/nanosystems.

The polyphasic approach used today in the taxonomy and systematics of the Bacteria and Archaea includes the use of phenotypic, chemotaxonomic and genotypic data. The use of 16S rRNA gene sequence data has revolutionized our understanding of the microbial world and led to a rapid increase in the number of descriptions of novel taxa, especially at the species level. It has allowed in many cases for the demarcation of taxa into distinct species, but its limitations in a number of groups have resulted in the continued use of DNA-DNA hybridization. As technology has improved, next-generation sequencing (NGS) has provided a rapid and cost-effective approach to obtaining whole-genome sequences of microbial strains. Although some 12,000 bacterial or archaeal genome sequences are available for comparison, only 1725 of these are of actual type strains, limiting the use of genomic data in comparative taxonomic studies when there are nearly 11,000 type strains. Efforts to obtain complete genome sequences of all type strains are critical to the future of microbial systematics. The incorporation of genomics into the taxonomy and systematics of the Bacteria and Archaea coupled with computational advances will boost the credibility of taxonomy in the genomic era. This special issue of International Journal of Systematic and Evolutionary Microbiology contains both original research and review articles covering the use of genomic sequence data in microbial taxonomy and systematics. It includes contributions on specific taxa as well as outlines of approaches for incorporating genomics into new strain isolation to new taxon description workflows.

We investigate the potential costs and benefits of firms constituting a heterogeneous pool of directors relative to more homogeneous boards. We measure director heterogeneity along six separate dimensions and divide board heterogeneity into occupational and social components. Our empirical analysis indicates that corporate complexity and managerial control exhibit significant influence on board heterogeneity. Using the heterogeneity of the county population of the firm's headquarters as an instrument, we also find that investors place valuation premiums on heterogeneous boards in complex firms but discount heterogeneity in less complex firms. Overall, our analysis indicates greater heterogeneity may not necessarily improve board efficacy.

The historical and presettlement relationships between drought and wildfire are well documented in North America, with forest fire occurrence and area clearly increasing in response to drought. There is also evidence that drought interacts with other controls (forest productivity, topography, fire weather, management activities) to affect fire intensity, severity, extent, and frequency. Fire regime characteristics arise across many individual fires at a variety of spatial and temporal scales, so both weather and climate - including short- and long-term droughts - are important and influence several, but not all, aspects of fire regimes. We review relationships between drought and fire regimes in United States forests, fire-related drought metrics and expected changes in fire risk, and implications for fire management under climate change. Collectively, this points to a conceptual model of fire on real landscapes: fire regimes, and how they change through time, are products of fuels and how other factors affect their availability (abundance, arrangement, continuity) and flammability (moisture, chemical composition). Climate, management, and land use all affect availability, flammability, and probability of ignition differently in different parts of North America. From a fire ecology perspective, the concept of drought varies with scale, application, scientific or management objective, and ecosystem.

UNLABELLED: In this era of insistence on evidence-based treatments, cognitive behavioral therapy (CBT) has emerged as a highly preferred choice for a spectrum of psychological disorders. Yet, it is by no means immune to some of the vagaries of client participation. Special concerns arise when clients drop out from treatment. OBJECTIVE: The aim of this study was to answer questions about the rate and timing of dropout from CBT, with specific reference to pretreatment versus during treatment phases. Also explored were several moderators of dropout. METHOD: A meta-analysis was performed on dropout data from 115 primary empirical studies involving 20,995 participants receiving CBT for a range of mental health disorders. RESULTS: Average weighted dropout rate was 15.9% at pretreatment, and 26.2% during treatment. Dropout was significantly associated with (a) diagnosis, with depression having the highest attrition rate; (b) format of treatment delivery, with e-therapy having the highest rates; (c) treatment setting, with fewer inpatient than outpatient dropouts; and (d) number of sessions, with treatment starters showing significantly reduced dropout as number of sessions increased. Dropout was not significantly associated with client type (adults or adolescents), therapist licensure status, study design (randomized control trial [RCT] vs. non-RCT), or publication recency. CONCLUSIONS: Findings are interpreted with reference to other reviews. Possible clinical applications include careful choice and supplementing of treatment setting/delivery according to the diagnosis, and use of preparatory strategies. Suggestions for future research include standardization of operational definitions of dropout, specification of timing of dropout, and exploration of additional moderator variables.

ABSTRACT The IceCube Collaboration has previously discovered a high-energy astrophysical neutrino flux using neutrino events with interaction vertices contained within the instrumented volume of the IceCube detector. We present a complementary measurement using charged current muon neutrino events where the interaction vertex can be outside this volume. As a consequence of the large muon range the effective area is significantly larger but the field of view is restricted to the Northern Hemisphere. IceCube data from 2009 through 2015 have been analyzed using a likelihood approach based on the reconstructed muon energy and zenith angle. At the highest neutrino energies between and a significant astrophysical contribution is observed, excluding a purely atmospheric origin of these events at significance. The data are well described by an isotropic, unbroken power-law flux with a normalization at neutrino energy of and a hard spectral index of . The observed spectrum is harder in comparison to previous IceCube analyses with lower energy thresholds which may indicate a break in the astrophysical neutrino spectrum of unknown origin. The highest-energy event observed has a reconstructed muon energy of which implies a probability of less than for this event to be of atmospheric origin. Analyzing the arrival directions of all events with reconstructed muon energies above no correlation with known γ -ray sources was found. Using the high statistics of atmospheric neutrinos we report the current best constraints on a prompt atmospheric muon neutrino flux originating from charmed meson decays which is below 1.06 in units of the flux normalization of the model in Enberg et al.

INTRODUCTION: Understanding, categorizing, and using implementation science theories, models, and frameworks is a complex undertaking. The issues involved are even more challenging given the large number of frameworks and that some of them evolve significantly over time. As a consequence, researchers and practitioners may be unintentionally mischaracterizing frameworks or basing actions and conclusions on outdated versions of a framework. METHODS: This paper addresses how the RE-AIM (Reach, Effectiveness, Adoption, Implementation, and Maintenance) framework has been described, summarizes how the model has evolved over time, and identifies and corrects several misconceptions. RESULTS: We address 13 specific areas where misconceptions have been noted concerning the use of RE-AIM and summarize current guidance on these issues. We also discuss key changes to RE-AIM over the past 20 years, including the evolution to Pragmatic Robust Implementation and Sustainability Model, and provide resources for potential users to guide application of the framework. CONCLUSIONS: RE-AIM and many other theories and frameworks have evolved, been misunderstood, and sometimes been misapplied. To some degree, this is inevitable, but we conclude by suggesting some actions that reviewers, framework developers, and those selecting or applying frameworks can do to prevent or alleviate these problems.

Evidence for an extraterrestrial flux of high-energy neutrinos has now been found in multiple searches with the IceCube detector. The first solid evidence was provided by a search for neutrino events with deposited energies $\gtrsim 30$ TeV and interaction vertices inside the instrumented volume. Recent analyses suggest that the extraterrestrial flux extends to lower energies and is also visible with throughgoing, νμ-induced tracks from the Northern Hemisphere. Here, we combine the results from six different IceCube searches for astrophysical neutrinos in a maximum-likelihood analysis. The combined event sample features high-statistics samples of shower-like and track-like events. The data are fit in up to three observables: energy, zenith angle, and event topology. Assuming the astrophysical neutrino flux to be isotropic and to consist of equal flavors at Earth, the all-flavor spectrum with neutrino energies between 25 TeV and 2.8 PeV is well described by an unbroken power law with best-fit spectral index −2.50 ± 0.09 and a flux at 100 TeV of $({6.7}_{-1.2}^{+1.1})\times {10}^{-18}\;{\mathrm{GeV}}^{-1}\;{{\rm{s}}}^{-1}\;{\mathrm{sr}}^{-1}\;{\mathrm{cm}}^{-2}$. Under the same assumptions, an unbroken power law with index −2 is disfavored with a significance of 3.8σ (p = 0.0066%) with respect to the best fit. This significance is reduced to 2.1σ (p = 1.7%) if instead we compare the best fit to a spectrum with index −2 that has an exponential cut-off at high energies. Allowing the electron-neutrino flux to deviate from the other two flavors, we find a νe fraction of 0.18 ± 0.11 at Earth. The sole production of electron neutrinos, which would be characteristic of neutron-decay-dominated sources, is rejected with a significance of 3.6σ (p = 0.014%).