864 research outputs found
An Application of Mixed Logit Estimation in the Analysis of Producers’ Stated Preferences
This paper analyzes Colorado Corn producers’ preferences over both private- and environmental public-good production system attributes. Current production practices are characterized by intensive water and chemical use, resulting in non-point source pollution to water bodies as well as soil erosion problems. Data from a stated preference survey are employed to analyze key attributes of experimentally configured irrigation systems, proposed as alternatives to current practices. Panel mixed logit estimations find positive preferences for profit, risk reduction, and, importantly, systems with less environmental impact in terms of nitrate leaching and soil erosion. The results also find presence of significant preference heterogeneity and a complementary relationship between the two environmental attributes. Analysis of this kind can be used by policy makers to predict behavioral responses associated with introduction of new technologies, or to assess welfare implications of agricultural policy changes and stricter environmental regulations.Agricultural production, profit-maximization, environment, mixed logit, stated preference, attribute part-worth, nitrate leaching, soil erosion, risk, Crop Production/Industries, C10, D62, Q12, Q15, Q51,
Are Agricultural PACs Monolithic? An Empirical Investigation
This paper analyzes donation strategies of agricultural PACs by examining and testing a variety of variables theoretically related to contributions and formally testing for equivalence of donation strategies across PACs of varying levels of aggregation. Both chambers of the 108th Congress were modeled, with particular attention paid to the targeting of different power or influence sources within the legislature. Results showed significant heterogeneity across PAC subaggregates within a chamber, as well as between chambers, in terms of overall strategy and magnitude of marginal impacts. Evidence supporting the conditional party government hypothesis where PACs target top Party officials rather than influential legislative members was mixed and subindustry specific, with chairmanships apparently less important in the Senate than in the House.Monolithic Behavior, Political Action Committee, Political Donation Strategies, Tobit model, Agricultural and Food Policy,
Leading, Learning, and Earning: Creating a Meaningful Student Employment Program
This book chapter outlines the student employment program at Brookens Library at the University of Illinois Springfield and provides practical strategies for application of a student employment program that is focused on student empowerment and student learning.Ope
Burn-Out Among Social Work Professionals: A Behavioral Approach to Causal and Interventive Knowledge
Although the phenomenon of staff burn-out represents a significant problem for the effective administration and functioning of social service settings, there has been a general paucity of empirically based research on this issue. The staggering financial, personal and social costs associated with staff burn-out emphasize the fact that we can no longer accept the sole use of descriptive and correlational studies of the problem. This paper suggests refocusing our theoretical perspective of the problem of staff burn-out from an emphasis on the dispositional qualities of burnedout staff members, to examining the social and situational contingencies of reinforcement responsible for the acquisition and maintenance of burnout. In addition, this paper discusses the application of experimental methodologies designed to identify causative factors and evaluate interventive procedures. It is believed that this approach will facilitate our understanding of the causes of burn-out and assist in developing effective interventive procedures
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A Tablespoon or Two Food Blog
A Tablespoon or Two is a food blog featuring recipes, featured folks, featured ingredients, an about me section, and my food history. The target audience is Pacific Northwest young chefs who like to cook affordable and fresh comfort food. The pages of the blog feature posts such as a trip to the Corvallis Farmers’ Market, a history of Lebanese cuisine and some profiles of local influential people in the Corvallis food community.
This thesis examines the process of creating a food blog by detailing which blogs and magazines provided inspiration, how my background as a new media communications major played a role in blogging and the content decisions that led to establishing a brand and logo. How improvements were made, the social media aspect and the blog future are discussed in great detail as crucial components to maintaining a successful food blog
First Results from the KMOS Lens-Amplified Spectroscopic Survey (KLASS): Kinematics of Lensed Galaxies at Cosmic Noon
We present the first results of the KMOS Lens-Amplified Spectroscopic Survey
(KLASS), a new ESO Very Large Telescope (VLT) large program, doing multi-object
integral field spectroscopy of galaxies gravitationally lensed behind seven
galaxy clusters selected from the HST Grism Lens-Amplified Survey from Space
(GLASS). Using the power of the cluster magnification we are able to reveal the
kinematic structure of 25 galaxies at , in four
cluster fields, with stellar masses . This sample includes 5 sources at with lower stellar masses
than in any previous kinematic IFU surveys. Our sample displays a diversity in
kinematic structure over this mass and redshift range. The majority of our
kinematically resolved sample is rotationally supported, but with a lower ratio
of rotational velocity to velocity dispersion than in the local universe,
indicating the fraction of dynamically hot disks changes with cosmic time. We
find no galaxies with stellar mass in our sample
display regular ordered rotation. Using the enhanced spatial resolution from
lensing, we resolve a lower number of dispersion dominated systems compared to
field surveys, competitive with findings from surveys using adaptive optics. We
find that the KMOS IFUs recover emission line flux from HST grism-selected
objects more faithfully than slit spectrographs. With artificial slits we
estimate slit spectrographs miss on average 60% of the total flux of emission
lines, which decreases rapidly if the emission line is spatially offset from
the continuum.Comment: Accepted for publication in Ap
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College student novice spreadsheet reasoning and errors
The spreadsheet has become a common technology tool and is now a predominant form of end-user programming. Some of the same features that make spreadsheets excellent tools for ad-hoc development can introduce errors into the final product. Although a variety of research has been performed investigating methods to detect errors in spreadsheets, little has been done to investigate initial reasoning errors. The spreadsheet error taxonomy developed by Rajalingham, Chadwick, and Knight (2001) includes categories for reasoning errors that have not yet been investigated. Previous studies have categorized errors in existing spreadsheets, but have not analyzed the source of the error. This study investigates the reasoning of college students while developing spreadsheets and examines the reasoning associated with errors generated in spreadsheet development. For this study, a phenomenological qualitative design incorporated a think-aloud protocol, interviews, and recordings of spreadsheet development of three purposefully-selected students. Data sources were analyzed to determine their reasoning, the types of errors produced based on the taxonomy, and associations between reasoning and errors.
The findings indicated that students used different types of reasoning in the mathematical phases of spreadsheet development than they do in the spreadsheet implementation phase. As novice spreadsheet developers, the students had significant difficulties translating problems into mathematical representations. Spreadsheet skills and concepts improved with practice through the course, but mathematical representations remained problematic. The students enjoyed using the spreadsheet as a tool for doing mathematical reasoning. Several themes emerged as the study progressed: Reasoning differences during mathematical and spreadsheet phases of development; using icons for functions affected conceptualization of the functions; copy operations were perceived as ―painting‖ rather than applying a formula to a series; and the effectiveness of the taxonomy for categorizing reasoning errors . The results suggested modifications to student learning experiences leading to more accurate spreadsheet development: Integrate spreadsheets into mathematics courses; increase education in spreadsheet development; integrate formal design and testing components to the spreadsheet curriculum; include spreadsheet errors in the curriculumKeywords: Reasoning, Spreadsheet, Errors, Educatio
The Grism Lens-Amplified Survey from Space (GLASS). XII. Spatially Resolved Galaxy Star Formation Histories and True Evolutionary Paths at z > 1
Modern data empower observers to describe galaxies as the spatially and
biographically complex objects they are. We illustrate this through case
studies of four, systems based on deep, spatially resolved, 17-band
+ G102 + G141 Hubble Space Telescope grism spectrophotometry. Using full
spectrum rest-UV/-optical continuum fitting, we characterize these galaxies'
observed kpc-scale structures and star formation rates (SFRs) and
reconstruct their history over the age of the universe. The sample's
diversity---passive to vigorously starforming; stellar masses to ---enables us to draw spatio-temporal inferences
relevant to key areas of parameter space (Milky Way- to super-Andromeda-mass
progenitors). Specifically, we find signs that bulge mass-fractions () and
SF history shapes/spatial uniformity are linked, such that higher s
correlate with "inside-out growth" and central specific SFRs that peaked above
the global average for all starforming galaxies at that epoch. Conversely, the
system with the lowest had a flat, spatially uniform SFH with normal peak
activity. Both findings are consistent with models positing a feedback-driven
connection between bulge formation and the switch from rising to falling SFRs
("quenching"). While sample size forces this conclusion to remain tentative,
this work provides a proof-of-concept for future efforts to refine or refute
it: JWST, WFIRST, and the 30-m class telescopes will routinely produce data
amenable to this and more sophisticated analyses. These samples---spanning
representative mass, redshift, SFR, and environmental regimes---will be ripe
for converting into thousands of sub-galactic-scale empirical windows on what
individual systems actually looked like in the past, ushering in a new dialog
between observation and theory.Comment: 18 pp, 15 figs, 3 tables (main text); 5 pp, 5 figs, 1 table
(appendix); Submitted to AAS Journals 1 October 201
Inferences on the Timeline of Reionization at z~8 From the KMOS Lens-Amplified Spectroscopic Survey
Detections and non-detections of Lyman alpha (Ly) emission from
galaxies ( Gyr after the Big Bang) can be used to measure the timeline of
cosmic reionization. Of key interest to measuring reionization's mid-stages,
but also increasing observational challenge, are observations at z > 7, where
Ly redshifts to near infra-red wavelengths. Here we present a search
for z > 7.2 Ly emission in 53 intrinsically faint Lyman Break Galaxy
candidates, gravitationally lensed by massive galaxy clusters, in the KMOS
Lens-Amplified Spectroscopic Survey (KLASS). With integration times of ~7-10
hours, we detect no Ly emission with S/N>5 in our sample. We determine
our observations to be 80% complete for 5 spatially and spectrally
unresolved emission lines with integrated line flux erg
s cm. We define a photometrically selected sub-sample of 29
targets at , with a median 5 Ly EW limit of 58A.
We perform a Bayesian inference of the average intergalactic medium (IGM)
neutral hydrogen fraction using their spectra. Our inference accounts for the
wavelength sensitivity and incomplete redshift coverage of our observations,
and the photometric redshift probability distribution of each target. These
observations, combined with samples from the literature, enable us to place a
lower limit on the average IGM neutral hydrogen fraction of at z ~ 8, providing further evidence of rapid reionization
at z~6-8. We show that this is consistent with reionization history models
extending the galaxy luminosity function to , with
low ionizing photon escape fractions, .Comment: Accepted for publication in MNRA
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