1,090 research outputs found
Comparison of students\u27 opinions toward experiential learning in two undergraduate agricultural capstone courses designed with contrasting delivery techniques
The purpose of this study was to determine similarities and differences in students\u27 perceptions towards learning in two senior-level farm management experientially based capstone courses, similar in content, but vastly different in delivery and teaching methods. A secondary purpose was to determine if there was a favorable means for teaching farm business management concepts to young adult learners.;The objectives of the study were: (1) To examine selected demographic characteristics of the students enrolled in these two experientially-based capstone courses. (2) To determine the effectiveness of these two capstone courses using Crunkilton\u27s criteria. (3) To identify the effectiveness of experiential learning, learning outcomes, and knowledge/skill enhancement as it occurs, using students\u27 perceptions towards these courses. (4) To compare students\u27 attitudes towards the effectiveness of various teaching and delivery methods used in each course and its impact upon their learning in an experiential setting.;A survey was developed and conducted to evaluate the AGEDS 450, Farm Management and Operation and ECON 430, Advanced Farm Business Management courses at Iowa State University. This survey was administered at the conclusion of the respective courses. The survey was administered at the end of the Fall 2003 semester to 61 students enrolled in ECON 430 and 37 students in AGEDS 450. Additionally, 31 students in the Spring 2004 AGEDS 450 course completed the survey. Therefore, responses were received from 61 ECON 430 students and 68 AGEDS 450 students.;Data analysis was accomplished through the use of demographic characteristics, means, standard deviations, rankings, and analysis of variance (ANOVA). The major discussion and findings indicated a favorable rating for using experiential learning within capstone courses in undergraduate agricultural education, specifically farm management. The data revealed positive student responses to capstone course effectiveness, learning outcomes, knowledge/skills enhancement, and delivery methods within the two courses. The study also provided some justification for the use of adult learning principles with undergraduate agricultural students.;A recommendation for further study and increased use of experiential learning, capstone courses and adult learning theory was provided. Implications within experiential learning, agricultural education and adult learning are also included
How marriages based on bride capture differ : Evidence from Kyrgyzstan
BACKGROUND: A significant proportion of women in the Kyrgyz Republic marry viaala kachuu,generally translated as bride capture or kidnapping. Many regard this practice asharmless elopement or a tradition; others perceive it as a form of forced marriage. OBJECTIVE: This paper contributes to the understanding ofala kachuu by exploring the extent towhich couples in these marriages differ from those in arranged or love marriages. METHODS: We use the 2013 wave of the Life in Kyrgyzstan survey to compute profile similarityindices for the personality of couples. We then regress marriage type on the profilesimilarity index, controlling for sociodemographic variables.RESULTSCouples in marriages resulting from bride capture are far less assortatively matched onpersonality traits than other couples, especially those who have only recently married. CONCLUSIONS: This greater dissimilarity is consistent withala kachuu being forced marriage ratherthan merely staged or ritualized elopement. CONTRIBUTION: This paper provides a novel source of evidence on the possible nonconsensual nature ofbride capture in Kyrgyzstan, adding further weight to those arguing that it is forced
How police use of force at arrest can lead to greater mental health problems among prison inmates.
In many arrests, police use force to restrain suspects, often when suspects are not resisting. But what are the long-term effects of the use of force on those who are arrested? Benjamin Meade, Benjamin Steiner, and Charles Klahm examine the effects of exposure to police use of force, finding that it is significantly associated with increased mental health problems among prison inmates. Such inmates were more likely to experience a greater number of both manic and depressive symptoms compared to those who were not exposed to violence upon arrest. They write that in light of their findings, police administrators may wish reexamine existing use of force policies, and prison administrators should identify inmates who were exposed to police use of force so that they might be assessed for trauma related needs
Using force in arrests against those who are not resisting can mean more violent prisoners.
Recent events have seen a re-evaluation of the relationship between the police and citizens, with increased concern about the use of force during arrests. In new research, Charles Klahm, Benjamin Steiner, and Benjamin Meade find another consequence of police using violent force during arrests: once in prison, inmates who did not resist their arrests were more likely to be involved in rule violations, including acts of violence. They argue that these inmates’ beliefs that their treatment was unfair mean that they may no longer believe in the legitimacy of the police, leading them to be less likely to cooperate with authorities
Quantitation of the Hydroxyl Radical by Reaction with Dimethyl Sulfoxide
This investigation was conducted to validate the use of dimethyl sulfoxide (DMSO) as a quantitative molecular probe for the generation of hydroxyl radicals (HO) in aqueous systems. Reaction of HO with DMSO produces methane sulfinic acid as a primary product, which can be detected by a simple calorimetric assay. To evaluate this method for estimating total HO production, we studied three model systems, including the Fenton reaction, irradiation of water, and ultraviolet photolysis of hydrogen peroxide, for which the theoretical maximum yield of HO could be calculated and compared to measured DMSO oxidation. The results confirm that 0.05 to 1 M DMSO may be used to capture nearly all of the expected HO radicals formed. Thus, methane sulfinic acid production from DMSO holds promise as an easily measured marker for HO formation in aqueous systems pretreated with DMSO
A model for implementing a college-wide experiential learning program in higher education
ScienceWith Practice (SWP) was conceptualized to provide opportunities for agriculture students to develop a planned learning component as part of their work experiences with faculty and staff in university research laboratories, farms, greenhouses, and other units. This college-wide program was designed and implemented using adult learning theory and best practices found in the literature. Activities included development of learning agreements, individual progress visits, regular student seminars, an end-of-experience symposium, a recognition banquet, and a formal evaluation. Students had opportunities to acquire technical agriculture skills; explore linkages between upperlevel coursework, research, and the world of work; develop skills related to organizing, planning, and conducting research; and consider graduate education and research as a potential career. Students earned academic credit for articulating their personal growth and what was learned. Student expectations included: 1) participation and communication; 2) a journal of activities and experiences; 3) a final report and reflection; 4) a formal 20-minute presentation; and 5) a comprehensive portfolio. Science With Practice developed into a program in which students took more responsibility for their work and connected their learning and work experiences and faculty transitioned from employers to mentors
Simulation of Free Radical Reactions in Biology and Medicine: A New Two-Compartment Kinetic Model of Intracellular Lipid Peroxidation
To explore mechanisms of free radical reactions leading to intracellular lipid peroxidation in living systems, we developed a computational model of up to 109 simultaneous enzymatic and free radical reactions thought to be involved in the initiation, propagation, and termination of membrane lipid peroxidation. Rate constants for the various reactions were obtained from the published literature. The simulation model included a lipid membrane compartment and an aqueous cytosolic compartment, between which various chemical species were partitioned. Lipid peroxidation was initiated by the iron-catalyzed, superoxide-driven Fenton reaction. A C -language computer program implemented numerical solution of the steady-state rate equations for concentrations of nine relevant free radicals. The rate equations were integrated by a modified Euler technique to describe the evolution with time of simulated concentrations of hydrogen peroxide, ferric and ferrous iron, unsaturated lipid, lipid hydroperoxides, superoxide anion, and biological antioxidants, including SOD and catalase. Initial results led to significant insights regarding mechanisms of membrane lipid peroxidation: 1. segregation and concentration of lipids within membrane compartments promotes chain propagation; 2. in the absence of antioxidants computed concentrations of lipid hydroperoxides increase linearly about 40 M/min during oxidative stress; 3. lipid peroxidation is critically dependent upon oxygen concentration and the modeled dependence is similar to the experimental function; 4. lipid peroxidation is rapidly quenched by the presence of Vitamin E-like antioxidants, SOD, and catalase; 5. only small (l to 50 M) amounts of free iron are required for initiation of lipid peroxidation; 6. substantial lipid peroxidation occurs only when cellular defense mechanisms have been weakened or overcome by prolonged oxidative stress, hence understanding of the balance between free radical generation and antioxidant defense systems is critical to the understanding and control of free radical reactions in biology and medicine
The Low-Spin Black Hole in LMC X-3
Building upon a new dynamical model for the X-ray binary LMC X-3, we measure
the spin of its black hole primary via the continuum-fitting method. We
consider over one thousand thermal-state RXTE X-ray spectra of LMC X-3. Using a
large subset of these spectra, we constrain the spin parameter of the black
hole to be spin = 0.21(+0.18,-0.22), 90% confidence. Our estimate of the
uncertainty in spin takes into account a wide range of systematic errors. We
discuss evidence for a correlation between a black hole's spin and the
complexity of its X-ray spectrum.Comment: Submitted to ApJL, 5 pages emulateapj, 2 figures and 1 tabl
Modeling the Optical-X-ray Accretion Lag in LMC X-3: Insights Into Black-Hole Accretion Physics
The X-ray persistence and characteristically soft spectrum of the black hole
X-ray binary LMC X-3 make this source a touchstone for penetrating studies of
accretion physics. We analyze a rich, 10-year collection of optical/infrared
(OIR) time-series data in conjunction with all available contemporaneous X-ray
data collected by the ASM and PCA detectors aboard the Rossi X-ray Timing
Explorer. A cross-correlation analysis reveals an X-ray lag of ~2 weeks.
Motivated by this result, we develop a model that reproduces the complex OIR
light curves of LMC X-3. The model is comprised of three components of
emission: stellar light; accretion luminosity from the outer disk inferred from
the time-lagged X-ray emission; and light from the X-ray-heated star and outer
disk. Using the model, we filter a strong noise component out of the
ellipsoidal light curves and derive an improved orbital period for the system.
Concerning accretion physics, we find that the local viscous timescale in the
disk increases with the local mass accretion rate; this in turn implies that
the viscosity parameter alpha decreases with increasing luminosity. Finally, we
find that X-ray heating is a strong function of X-ray luminosity below ~50% of
the Eddington limit, while above this limit X-ray heating is heavily
suppressed. We ascribe this behavior to the strong dependence of the flaring in
the disk upon X-ray luminosity, concluding that for luminosities above ~50% of
Eddington, the star lies fully in the shadow of the disk.Comment: Accepted in ApJ (12 pages long in emulateapj format
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