1,183 research outputs found
Canada in a Climate Disrupted World
Climate change has already begun impacting economies and societies across the globe, and its impacts are expected to increase into the future. Adaptation to climate change is and will continue to be one of the greatest policy challenges facing the Canadian government. However, im- portant and much-needed work on understanding the future of climate change has not yet been completed. Gaps remain in the body of academic, government, and other policy-relevant publications. Specifically, there is a relative paucity of research done on the indirect impacts of climate change on Canada. These external impacts outside of Canada’s borders may have second-order effects, the implications of which have thus far remained largely unexplored. In this report, we identify key issue areas which are currently or potentially affected by these indirect impacts. We also undergo a thorough literature review, and locate areas in which further data re- search is required
A catch-free stock assessment model with application to goliath grouper (Epinephelus itajara) off southern Florida
Many modern stock assessment methods provide the machinery for determining the status of a stock in relation to certain reference points and for estimating how quickly a stock can be rebuilt. However, these methods typically require catch data, which are not always available. We introduce a model-based framework for estimating reference points, stock status, and recovery times in situations where catch data and other measures of absolute abundance are unavailable. The specif ic estimator developed is essentially an age-structured production model recast in terms relative to pre-exploitation levels. A Bayesian estimation scheme is adopted to allow the incorporation of pertinent auxiliary information such as might be obtained from meta-analyses of similar stocks or anecdotal observations. The approach is applied to the population of goliath grouper (Epinephelus itajara) off southern Florida, for which there are three indices of relative abundance but no reliable catch data. The results confirm anecdotal accounts of a marked decline in abundance during the 1980s followed by a substantial increase after the harvest of goliath grouper was banned in 1990. The ban appears to have reduced fishing pressure to between 10% and 50% of the levels observed during the 1980s. Nevertheless, the predicted fishing mortality rate under the ban appears to remain substantial, perhaps owing to illegal harvest and depth-related release mortality. As a result, the base model predicts that there is less than a 40% chance that the spawning biomass will recover to a level that would produce a 50% spawning potential ratio
Is the Custom Service Industry\u27s Role in Precision Agriculture Linked to Workforce Development?
Retail dealership survey data suggests that the lack of a qualified precision agriculture (PA) workforce limits the ability of the PA service industry to provide technological knowledge and services to producers who have adopted PA technology. The key empirical findings suggest that retail dealerships have the greatest difficulty finding workers who have, a) the capability to operate and collect data using specialized PA technology, b) the capability to interpret and develop management strategies using PA generated data, and c) a basic generalized competency in PA technology and its applications. The perceived shortage of skilled workers suggests that there is a need to expand the PA workforce with individuals who have knowledge, skills, and abilities (KSAs). A PA qualified workforce is necessary to provide support for the provision of PA services to current users of PA technology and new PA adopters
Knowledge, Skills, and Abilities in the Precision Agriculture Workforce: An Industry Survey
Precision agriculture encompasses a set of related technologies aimed at better utilizing crop inputs, increasing yield and quality, reducing production risks, and enabling information flow throughout the crop supply and end-use chains. As agricultural businesses invest in precision offerings, their capacity to provide these products and services will depend on their ability to hire and retain employees with appropriate proficiency as defined in their knowledge, skills, and abilities (KSAs). A 2015 survey of agricultural retailers examined the minimum educational requirements retailers were seeking in their hires, along with the importance of a list of KSAs for the various positions that they customarily fill. The positions included equipment operators, sales specialists, technical support, and agronomists. The KSAs included specifics, such as the ability to install, calibrate, troubleshoot, and repair equipment; knowledge of precision agriculture software; and also more broad skills such as effective written and verbal communication and in making agronomy recommendations. As expected, retailers expressed different educational minimums and different levels of importance for various positions. Overwhelmingly, the retailers indicated difficulty in finding qualified candidates and a predominance of candidates with low or deficient proficiency in areas they rated important. The survey was accomplished using email lists from both CropLife and the Certified Crop Adviser program
The Custom Service Industry\u27s Role in Precision Agriculture Adoption: A Literature Review
This literature review focuses on the role of the precision agriculture (PA) custom services industry in facilitating farmer adoption of PA technology. Based on the review, a series of stylized facts are developed that characterize the custom services industry\u27s role in the PA adoption process in the United States. The literature suggests that increasing the availability of custom services in local agricultural production markets will positively influence the rate of PA adoption. Recent PA custom services industry field surveys, however, indicate that skilled labor, proficient in PA technology, is critical to develop and provide custom services needed to increase the supply of PA services to farmers. These surveys suggest that currently there is a shortage of qualified labor to work in the PA custom services sector. The PA labor issue appears to pose a potential barrier to the provision of PA technical training desired by customers, and the deployment of PA custom services to customers who have adopted or are considering the adoption of PA technology
Global patterns and drivers of ecosystem functioning in rivers and riparian zones
River ecosystems receive and process vast quantities of terrestrial organic carbon, the fate of which depends strongly on microbial activity. Variation in and controls of processing rates, however, are poorly characterized at the global scale. In response, we used a peer-sourced research network and a highly standardized carbon processing assay to conduct a global-scale field experiment in greater than 1000 river and riparian sites. We found that Earth’s biomes have distinct carbon processing signatures. Slow processing is evident across latitudes, whereas rapid rates are restricted to lower latitudes. Both the mean rate and variability decline with latitude, suggesting temperature constraints toward the poles and greater roles for other environmental drivers (e.g., nutrient loading) toward the equator. These results and data set the stage for unprecedented “next-generation biomonitoring” by establishing baselines to help quantify environmental impacts to the functioning of ecosystems at a global scale
Fish growth changes over time in a Midwestern USA lake
Growth of Walleye Sander vitreus, Yellow Bass Morone mississippiensis, Common Carp Cyprinus carpio, and Black Bullhead Ameiurus melas was assessed in Clear Lake, Iowa, USA, over several decades and in relation to environmental variables. Growth of Common Carp was positively correlated with phytoplankton concentration. Recent Black Bullhead growth was faster than in the 1950s and 1990s, which may be a consequence of their recent decline in abundance. Growth of Common Carp and Yellow Bass was faster in the 1940s than in more recent time periods. Relative to their entire range, Common Carp first year growth was below average whereas length at later ages was above average. Walleye relative growth showed a similar pattern. The large changes in growth over several decades suggest that as the Clear Lake ecosystem continues to change, growth rates of its important fish species are also likely to continue changing
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The formation and evolution of dust in semi-analytic models of galaxy formation
The formation and evolution of galaxies is an interesting subject to study because it incorporates
astrophysics from all scales, from the initial perturbations in the early universe
creating the large scale structures that produce galaxies, right down to the evolution of
stellar populations and their manipulation of the host galaxy. Simulations of galaxy formation
allow us to test the various physical recipes against that which is observed in order
to build a true and proper picture of what is happening in the real universe.
L-Galaxies is a semi-analytic model of galaxy formation built on top of the merger
trees from the Millennium dark matter simulation, and is constrained to match certain key
observations at low redshift by applying a Monte Carlo Markov Chain (MCMC) method
to constrain the free parameters. In using the model to make high redshift predictions
of the stellar mass function, UV luminosity function and star formation rate distribution
function we found that the model starts to deviate from observational constraints at the
highest redshifts, particularly in high mass galaxies. In the case of the UV luminosity
function, this is because the current dust model is calibrated at low redshift and lacks
sophistication in that it only depends on the cold gas mass and the density of metals.
To improve on this we implement a physically motivated dust model that traces the
formation of dust from stellar sources, such as in the stellar winds of AGB stars and in
the supernovae remnants of massive stars, the growth of dust inside molecular clouds, and
the destruction of dust due to supernovae explosions. The model is fully integrated into
L-Galaxies such that the evolution of dust is included in all the recipes relevant to the
formation and evolution of galaxies, including: star formation; radiative feedback; cooling
and reheating; and both major and minor mergers.
Our results show a good fit to observations of the dust mass in galaxies both in the
local universe and out to high redshift and we note a similar conclusion as in the literature
that dust growth inside molecular clouds is not only necessary but the dominant source
of the dust mass in these galaxies. However, stellar sources of dust can not be neglected
as molecular clouds must first be seeded by dust grains in order for accretion to occur.
This could be important in the very early universe, perhaps for the first galaxies that
will hopefully be observed by JWST in the future, because these galaxies may not have
had sufficient time to seed their molecular clouds and as such the dust produced by these
stellar sources would be important for calculating the galaxies true observed luminosity.
We finish by discussing the limitations of the model and discuss areas for possible
improvement as well as the next steps in using this to better predict the luminosity of
galaxies in future models
Senior Recital: Lindsay Peterson, mezzo-soprano
This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Music Education. Ms. Peterson studies voice with Todd Wedge.https://digitalcommons.kennesaw.edu/musicprograms/2207/thumbnail.jp
Spring Clipping, Fire, and Simulated Increased Atmospheric Nitrogen Deposition Effects on Tallgrass Prairie Vegetation
Defoliation aimed at introduced cool-season grasses, which uses similar resources of native grasses, could substantially reduce their competitiveness and improve the quality of the northern tallgrass prairie. The objective was to evaluate the use of early season clipping and fire in conjunction with simulated increased levels of atmospheric nitrogen deposition on foliar canopy cover of tallgrass prairie vegetation. This study was conducted from 2009 to 2012 at two locations in eastern South Dakota. Small plots arranged in a split-plot treatment design were randomized in four complete blocks on a warm-season grass interseeded and a native prairie site in east-central South Dakota. The whole plot consisted of seven treatments: annual clip, biennial clip, triennial clip, annual fire, biennial fire, triennial fire, and undefoliated control. The clip plots consisted of weekly clipping in May to simulate heavy grazing. Fire was applied in late April or early May. The subplot consisted of nitrogen applied at 0 or 15 kg N · ha−1 in early June. All treatments were initially applied in 2009. Biennial and triennial treatments were reapplied in 2011 and 2012, respectively. Canopy cover of species/major plant functional groups was estimated in late August/early September. Annual clipping was just as effective as annual fire in increasing native warm-season grass and decreasing introduced cool-season grass cover. Annual defoliation resulted in greater native warm-season grass cover, less introduced cool-season grass cover, and less native cool-season grass cover than biennial or triennial defoliation applications. Low levels of nitrogen did not affect native warm-season grass or introduced cool-season cover for any of the defoliation treatments, but it increased introduced cool-season grass cover in the undefoliated control at the native prairie site. This study supports the hypothesis that appropriately applied management results in consistent desired outcomes regardless of increased simulated atmospheric nitrogen depositions
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