576 research outputs found
The Economic Importance of the Bristol Bay Salmon Industry
By any measure, the Bristol Bay sockeye salmon fishery is very large and valuable. It is the worldâs most
valuable wild salmon fishery, and typically supplies almost half of the worldâs wild sockeye salmon. In
2010, harvesting, processing, and retailing Bristol Bay salmon and the multiplier effects of these activities
created 165 million in direct
harvest value alone. That represented 31% of the total Alaska salmon harvest value, and was greater
than the total value of fish harvests in 41 states. Salmon processing in Bristol Bay increased the value by
390 million. The total value of Bristol
Bay salmon product exports in 2010 was about 500 million in income. For every dollar of direct output
value created in Bristol Bay fishing and processing, more than two additional dollars of output value are
created in other industries, as payments from the Bristol Bay fishery ripple through the economy. These
payments create almost three jobs for every direct job in Bristol Bay fishing and processing.
United States domestic consumption of Bristol Bay frozen sockeye salmon products has been growing
over time as a result of sustained and effective marketing by the industry, new product development and
other factors. This growth is likely to continue over time, which will result in even greater output value
figures for the industryâs economic impacts across the U.S.
The economic importance of the Bristol Bay salmon industry extends far beyond Alaska, particularly to
the West Coast states of Washington, Oregon and California.Bristol Bay Regional Seafood Development Associatio
UA Research Summary No. 15
Utterly worthless. Thatâs how a congressman from Missouri
described Alaska in 1867, when the U.S. bought it from Russia. A
lot of Americans agreed. For almost 100 years, hardly anyoneâ
except some Alaskansâwanted Alaska to become a state.
But Alaska did finally become a state, in 1959. Today, after
142 years as a U.S. possession and 50 years as a state, Alaska has
produced resources worth (in todayâs dollars) around 7.2 million for Alaska, equal to about $106 million
now. For perspective, thatâs roughly what the state government
collected in royalties from oil produced on state-owned land in just
the month of March 2009.
To help mark 50 years of statehood, this publication first takes
a broad look at whatâs changed in Alaska since 1959. Thatâs on
this page and the back page. Weâve also put together a timeline
of political and economic events in Alaska from 1867 to the present.
Thatâs on the inside pages. Thereâs an interactive version of the
timelineâwith photos, figures, and moreâon ISERâs Web site:
www.iser.uaa.alaska.edu
Adversarially Learned Anomaly Detection on CMS Open Data: re-discovering the top quark
We apply an Adversarially Learned Anomaly Detection (ALAD) algorithm to the
problem of detecting new physics processes in proton-proton collisions at the
Large Hadron Collider. Anomaly detection based on ALAD matches performances
reached by Variational Autoencoders, with a substantial improvement in some
cases. Training the ALAD algorithm on 4.4 fb-1 of 8 TeV CMS Open Data, we show
how a data-driven anomaly detection and characterization would work in real
life, re-discovering the top quark by identifying the main features of the
t-tbar experimental signature at the LHC.Comment: 16 pages, 9 figure
Identifying performance limiting parameters in perovskite solar cells using machine learning
Herein, it is shown that machine learning (ML) methods can be used to predict the parameter that limits the solar-cell performance most significantly, solely based on the current densityâvoltage (JâV) curve under illumination. The data (11â150 JâV curves) to train the model is based on device simulation, where 20 different physical parameters related to charge transport and recombination are varied individually. This approach allows to cover a wide range of effects that could occur when varying fabrication conditions or during degradation of a device. Using ML, the simulated JâV curves are classified for the changed parameter with accuracies above 80%, where Random Forests perform best. It turns out that the key parameters, short-circuit current density, open-circuit voltage, maximum power conversion efficiency, and fill factor are sufficient for accurate predictions. To show the practical relevance, the ML algorithms are then applied to reported devices, and the results are discussed from a physics perspective. It is demonstrated that if some specified conditions are met, satisfying results can be reached. The proposed workflow can be used to better understand a device's behavior, e.g., during degradation, or as a guideline to improve its performance without costly and time-consuming lab-based trial-and-error methods
Size dependent exciton dynamics in one-dimensional perylene bisimide aggregates
The size dependent exciton dynamics of one-dimensional aggregates of
substituted perylene bisimides are studied by ultrafast transient absorption
spectroscopy and kinetic Monte-Carlo simulations in dependence on the
temperature and the excitation density. For low temperatures the aggregates can
be treated as infinite chains and the dynamics is dominated by diffusion driven
exciton-exciton annihilation. With increasing temperature the aggregates
decompose into small fragments consisting of very few monomers. This scenario
is also supported by the time dependent anisotropy deduced from polarization
dependent experiments
Methods to estimate the between-study variance and its uncertainty in meta-analysis
Metaâanalyses are typically used to estimate the overall/mean of an outcome of interest. However, inference about betweenâstudy variability, which is typically modelled using a betweenâstudy variance parameter, is usually an additional aim. The DerSimonian and Laird method, currently widely used by default to estimate the betweenâstudy variance, has been long challenged. Our aim is to identify known methods for estimation of the betweenâstudy variance and its corresponding uncertainty, and to summarise the simulation and empirical evidence that compares them. We identified 16 estimators for the betweenâstudy variance, seven methods to calculate confidence intervals, and several comparative studies. Simulation studies suggest that for both dichotomous and continuous data the estimator proposed by Paule and Mandel and for continuous data the restricted maximum likelihood estimator are better alternatives to estimate the betweenâstudy variance. Based on the scenarios and results presented in the published studies, we recommend the Qâprofile method and the alternative approach based on a âgeneralised Cochran betweenâstudy variance statisticâ to compute corresponding confidence intervals around the resulting estimates. Our recommendations are based on a qualitative evaluation of the existing literature and expert consensus. Evidenceâbased recommendations require an extensive simulation study where all methods would be compared under the same scenarios. © 2015 The Authors. Research Synthesis Methods published by John Wiley & Sons Ltd
High prevalence and factors associated with the distribution of the integron intI1 and intI2 genes in Scottish cattle herds
Integrons are genetic elements that capture and express antimicrobial resistance genes within arrays, facilitating horizontal spread of multiple drug resistance in a range of bacterial species. The aim of this study was to estimate prevalence for class 1, 2, and 3 integrons in Scottish cattle and examine whether spatial, seasonal or herd management factors influenced integron herd status. We used fecal samples collected from 108 Scottish cattle herds in a national, cross-sectional survey between 2014 and 2015, and screened fecal DNA extracts by multiplex PCR for the integrase genes intI1, intI2, and intI3. Herd-level prevalence was estimated [95% confidence interval (CI)] for intI1 as 76.9% (67.8â84.0%) and intI2 as 82.4% (73.9â88.6%). We did not detect intI3 in any of the herd samples tested. A regional effect was observed for intI1, highest in the North East (OR 11.5, 95% CI: 1.0â130.9, P = 0.05) and South East (OR 8.7, 95% CI: 1.1â20.9, P = 0.04), lowest in the Highlands. A generalized linear mixed model was used to test for potential associations between herd status and cattle management, soil type and regional livestock density variables. Within the final multivariable model, factors associated with herd positivity for intI1 included spring season of the year (OR 6.3, 95% CI: 1.1â36.4, P = 0.04) and watering cattle from a natural spring source (OR 4.4, 95% CI: 1.3â14.8, P = 0.017), and cattle being housed at the time of sampling for intI2 (OR 75.0, 95% CI: 10.4â540.5, P < 0.001). This study provides baseline estimates for integron prevalence in Scottish cattle and identifies factors that may be associated with carriage that warrant future investigation
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