746 research outputs found
THE SKY IS FALLING: AN EXAMINATION OF BROILER CONTRACT DESIGN AND GROWER REVENUES
A math program is used to examine an integrators problem of assigning broiler growers into settlement pools. The integrator varies the size and frequency of flock placements by grower ability. This differentiates grower incentives by ability. Which growers receive the strongest incentives depends on amount of excess grow-out capacity.Research Methods/ Statistical Methods,
The asymmetric profile of the H76 alpha line emission from MWC349
MWC349 is an emission-line star found by Merrill, Humason and Burwell (1932). Braes, Habing and Schoenmaker (1972) discovered that it is a strong radio source. The radio emission originates in a massive ionized wind that is expanding with a velocity of about 50 km s(-1). Its continuum spectrum fits well a nu(0.6) power law from the cm wavelengths to the far-IR. Radio recombination line emission from the envelope of MWC349 was first detected by Altenhoff, Strittmatter and Wendker (1981). We have obtained good signal-to-noise ratio, Very Large Array observations of the H76 alpha radio recombination line from the ionized wind of MWC349. Our data reveal that the profile is markedly asymmetric, with a steep rise on the blue side. This asymmetry could be due to non-LTE effects in the formation and transfer of the line or to intrinsic asymmetries in the envelope. Our analysis suggests that most probably the peculiar profile is caused by a non-LTE enhancement of the line emission from the side of the envelope nearer to the observer. This asymmetry has the opposite sense than that observed in optical and IR recombination lines, where a different effect (absorption of the stellar continuum by the gas in the wind between the star and the observer) is known to be dominant, leading to the classic P Cygni profile. We propose that the profiles of the radio recombination lines from ionized stellar winds will have this characteristic shape, while optical and IR recombination lines are characterized by P Cygni-like profiles. Unfortunately, at present the detection of radio recombination lines from ionized stellar winds is only feasible for MWC349 and a few other objects
Skeletally Diverse Small Molecules Using a Build/Couple/Pair Strategy
Intermolecular couplings of simple building blocks using catalytic, stereoselective cross-Mannich reactions followed by intramolecular functional group-pairing reactions of easily accessed variants of the Mannich products are explored as a route to skeletally diverse small molecules. The synthetic pathway yields products having 12 different skeletons using only three steps and has the potential to enable substantial stereochemical diversification in the future
Hearing and Vestibular Loss with Misuse of Opioids and Illicit Drugs: A Review of the Literature
Background: The purpose of this review was to summarize the literature regarding the effects of opioids and illicit drugs on the auditory and vestibular systems.
Methods: Data were sourced from published papers reporting hearing loss (HL) and/or vestibular loss (VL) following misuse or overdose of opioids or illicit drugs. Most papers consisted of retrospective single-case reports, with few retrospective reviews or prospective cohort studies. Search terms included variations of HL, VL, opioids, and illicit drugs. Search results yielded 51 articles published between 1976 and 2021. A total of 44 articles were reviewed after excluding studies that were not available in English (n = 3), only described acute effects in healthy cohorts (n = 3) or only described general health aspects in a group on methadone maintenance (n = 1).
Results: Sixteen studies reported ototoxicity from illicit drugs, 27 from prescription opioids, and 1 was unspecified. This review shows that HL associated with amphetamines and cocaine was typically sudden, bilateral, and temporary. HL from cocaine/ crack and heroin often presented with greatest losses in the mid-frequency range. HL associated with opioids was typically sudden, bilateral, moderately severe to profound, and in most cases permanent. The literature is sparse regarding VL from illicit drugs and opioids.
Conclusion: Practitioners who see patients for sudden or rapidly progressive HL or VL with no apparent cause should inquire about misuse of illicit drugs and opioids, particularly when the HL does not respond to steroid treatment
Surface Acoustic Wave Single-Electron Interferometry
We propose an experiment to observe interference of a single electron as it
is transported along two parallel quasi-one-dimensional channels trapped in a
single minimum of a travelling periodic electric field. The experimental device
is a modification of the surface acoustic wave (SAW) based quantum processor.
Interference is achieved by creating a superposition of spatial wavefunctions
between the two channels and inducing a relative phase shift via either a
transverse electric field or a magnetic field. The interference can be used to
estimate the decoherence time of an electron in this type of solid-state
device
Vestibular Evoked Myogenic Potential (VEMP) Test-Retest Reliability in Children
Objective—Vestibular evoked myogenic potentials (VEMPs) are short-latency muscle potentials measured from the neck (cervical VEMP; cVEMP) or under the eyes (ocular VEMP; oVEMP), which provide information regarding function of the saccule and utricle, respectively. VEMPs are reliable when performed in adults; however, reliability of VEMPs in children is unknown. Therefore, the purpose of the study was to determine the test-retest reliability of c- and oVEMP testing in normal control children.
Study Design—Prospective.
Setting—Hospital.
Patients—Ten adults, 14 adolescent children and 13 young children with normal hearing.
Interventions—c- and oVEMP testing were completed across two test sessions in response to air-conduction 500 Hz tone-burst and impulse hammer stimuli. Additionally, oVEMP was completed using eyes-open and eyes-closed conditions.
Main Outcome Measures—Intraclass correlation coefficients were calculated to determine the reliability of c- and oVEMP outcomes.
Results—When using air-conduction stimuli, c- and oVEMP amplitudes are reliable across test sessions in normal control children and adults. With impulse hammer stimuli, cVEMP amplitudes showed high reliability; however, oVEMP amplitudes showed low reliability in both eyes-open and eyes-closed conditions. Comparison between eyes-open and eyes-closed oVEMP conditions revealed shorter latencies and higher peak-to-peak amplitudes in the eyes-open condition.
Conclusions—In this small cohort of normal control children, cVEMPs are reliable using air-conduction and impulse hammer stimuli and oVEMPs are reliable using air-conduction stimuli in the eyes-open condition. oVEMP in eyes-closed conditions were less reliable compared to eyes-open conditions and resulted in a large number of absent responses
Gamma Ray Burst Neutrinos Probing Quantum Gravity
Very high energy, short wavelength, neutrinos may interact with the
space-time foam predicted by theories of quantum gravity. They would propagate
like light through a crystal lattice and be delayed, with the delay depending
on the energy. This will appear to the observer as a violation of Lorenz
invariance. Back of the envelope calculations imply that observations of
neutrinos produced by gamma ray bursts may reach Planck-scale sensitivity. We
revisit the problem considering two essential complications: the imprecise
timing of the neutrinos associated with their poorly understood production
mechanism in the source and the indirect nature of their energy measurement
made by high energy neutrino telescopes.Comment: 14 pages, 2 figure
The Voices and Choices of Women in the Academy
While it is clear that gender inequity still exists, this situation is compounded by race, ethnicity and sexism. The daily experiences of women confirm that racism and sexism is alive and well. This article presents and examines the experiences of Latino, Black, Arab, and Asian professional women and the consequences of their career decisions. Synthesized with literature, conceptual patterns of significance are noted for young girls and women of color aspiring and pursuing professional careers in education. The strategies utilized by these diverse professional women to cope with the trials and tribulations of contemporary educational and professional challenges are reviewed. It is necessary to continue to educate the public about the struggles and successes of women of diverse backgrounds to assist both high school and college age women as they prepare to contribute to the global economy of the 21st century.https://digitalcommons.georgiasouthern.edu/jiasgag/1004/thumbnail.jp
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