2,242 research outputs found
Alternative Measures of Risk in Commodity Supply Models: An Analysis of Sow Farrowing Decisions in the United States
The role of price risk in sow farrowings is investigated by using bivariate ARCH-M and GARCH-M models and a nonparametric kernel estimator. To account for the relevant time horizon of irreversible supply decisions, predictions for mean price and conditional price variance are iterated forward. The empirical results vary markedly in terms of their implications for risk response in hog supply decisions, with the ARCH-M and GARCH-M models suggesting a small and negative risk effect. Estimates of the marginal risk premium also indicate moderate and variable departures from marginal cost pricing in sow far rowing supply decisions
Mandates and the Incentive for Environmental Innovation
Mandates are policy tools that are becoming increasingly popular to promote renewable energy use. In addition to mitigating the pollution externality of conventional energy, mandates have the potential to promote R&D investments in renewable energy technology. But how well do mandates perform as innovation incentives? To address this question, we develop a partial equilibrium model with endogenous innovation to examine the R&D incentives induced by a mandate, and compare this policy to two benchmark situations: laissez-faire and a carbon tax. Innovation is stochastic and the model permits an endogenous number of multiple innovators. We find that mandates can improve upon laissez faire, and that the prospect of innovation is essential for their desirability. However, mandates suffer from several limitations. A mandate creates relatively strong incentives for investment in R&D in low-quality innovations, but relatively weak incentives to invest in high-quality innovations, so that the dispersion of realized innovation quality is comparatively low. Moreover, a mandate achieves lower welfare than a carbon tax, and its optimal level is more sensitive to the structure of the innovation process
How to test for phasic modulation of neural and behavioural responses.
Research on whether perception or other processes depend on the phase of neural oscillations is rapidly gaining popularity. However, it is unknown which methods are optimally suited to evaluate the hypothesized phase effect. Using a simulation approach, we here test the ability of different methods to detect such an effect on dichotomous (e.g., "hit" vs "miss") and continuous (e.g., scalp potentials) response variables. We manipulated parameters that characterise the phase effect or define the experimental approach to test for this effect. For each parameter combination and response variable, we identified an optimal method. We found that methods regressing single-trial responses on circular (sine and cosine) predictors perform best for all of the simulated parameters, regardless of the nature of the response variable (dichotomous or continuous). In sum, our study lays a foundation for optimized experimental designs and analyses in future studies investigating the role of phase for neural and behavioural responses. We provide MATLAB code for the statistical methods tested
The Role of Targeted HIV Screening in the Emergency Department:A Scoping Review
BACKGROUND: Human immunodeficiency virus (HIV) infection continues to expand worldwide and a significant proportion of infection is still undiagnosed. Recent studies have addressed the impact and feasibility of 'opt-out' HIV screening in Emergency Departments (EDs) in urban settings at high HIV prevalence, whereas little is known about the yield of implementing 'targeted' HIV testing especially in low-prevalence areas.OBJECTIVE: The present study undertakes a scoping review of research carried out on the implementation of targeted HIV screening in adult EDs to determine the impact, feasibility and acceptability of HIV testing in different HIV prevalence settings.DESIGN: Online databases (EMBASE, MEDLINE) were used to identify papers published between 2000 to 2020. A threeconcept search was employed with HIV (HIV, Human immunodeficiency virus infection, HIV infections), targeted testing (Target, screening or testing) and emergency medicine (Emergency Service, emergency ward, A&E, accident and emergency or Emergency Department) (28th February 2020). Only full-text articles written in English, French, Spanish or Italian and using impact and/or feasibility and/or acceptability of the program as primary or secondary outcomes were analysed.RESULTS: The search returned 416 articles. Of these, 12 met inclusion criteria and were included in the final review. Most of the included studies were carried out in the United States (n=8; 67%) and in areas of high HIV prevalence (n=11; 92%). Three (20%) were randomized control studies. While the rate of newly diagnosed HIV cases varied widely (0.03-2.2%), likely due to methodological heterogeneity between studies, the linkage of new HIV diagnosis was often high (80-100%) and median CD4+ cell count was always greater than 200 cells per microliter. Targeted HIV screening was found to be cost-effective (out of 2 studies) and well accepted by participants (out 2 studies).CONCLUSIONS: Targeted HIV screening at the ED can be impactful, feasible and well accepted, but often requires extra funding and staff. Most previous work has focused on areas of high disease prevalence
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Zebrafish behavioural profiling identifies GABA and serotonin receptor ligands related to sedation and paradoxical excitation.
Anesthetics are generally associated with sedation, but some anesthetics can also increase brain and motor activity-a phenomenon known as paradoxical excitation. Previous studies have identified GABAA receptors as the primary targets of most anesthetic drugs, but how these compounds produce paradoxical excitation is poorly understood. To identify and understand such compounds, we applied a behavior-based drug profiling approach. Here, we show that a subset of central nervous system depressants cause paradoxical excitation in zebrafish. Using this behavior as a readout, we screened thousands of compounds and identified dozens of hits that caused paradoxical excitation. Many hit compounds modulated human GABAA receptors, while others appeared to modulate different neuronal targets, including the human serotonin-6 receptor. Ligands at these receptors generally decreased neuronal activity, but paradoxically increased activity in the caudal hindbrain. Together, these studies identify ligands, targets, and neurons affecting sedation and paradoxical excitation in vivo in zebrafish
Decision-Making Authority, Team Efficiency and Human Worker Satisfaction in Mixed Human-Robot Teams
has opened up the possibility of integrating highly autonomous mobile robots into human teams. However, with this capability comes the issue of how to maximize both team efficiency and the desire of human team members to work with robotic counterparts. We hypothesized that giving workers partial decision-making authority over a task allocation process for the scheduling of work would achieve such a maximization, and conducted an experiment on human subjects to test this hypothesis. We found that an autonomous robot can outperform a worker in the execution of part or all of the task allocation (p < 0.001 for both). However, rather than finding an ideal balance of control authority to maximize worker satisfaction, we observed that workers preferred to give control authority to the robot (p < 0.001). Our results indicate that workers prefer to be part of an efficient team rather than have a role in the scheduling process, if maintaining such a role decreases their efficiency. These results provide guidance for the successful introduction of semi-autonomous robots into human teams. I
Mis-splicing of the GALNS gene resulting from deep intronic mutations as a cause of Morquio a disease
Background
Mucopolysaccharidosis-IVA (Morquio A disease) is a lysosomal disorder in which the abnormal accumulation of keratan sulfate and chondroitin-6-sulfate is consequent to mutations in the galactosamine-6-sulfatase (GALNS) gene. Since standard DNA sequencing analysis fails to detect about 16% of GALNS mutant alleles, gross DNA rearrangement screening and uniparental disomy evaluation are required to complete the molecular diagnosis. Despite this, the second pathogenic GALNS allele generally remains unidentified in ~ 5% of Morquio-A disease patients.
Methods
In an attempt to bridge the residual gap between clinical and molecular diagnosis, we performed an mRNA-based evaluation of three Morquio-A disease patients in whom the second mutant GALNS allele had not been identified. We also performed sequence analysis of the entire GALNS gene in two patients.
Results
Different aberrant GALNS mRNA transcripts were characterized in each patient. Analysis of these transcripts then allowed the identification, in one patient, of a disease-causing deep intronic GALNS mutation. The aberrant mRNA products identified in the other two individuals resulted in partial exon loss. Despite sequencing the entire GALNS gene region in these patients, the identity of a single underlying pathological lesion could not be unequivocally determined. We postulate that a combination of multiple variants, acting in cis, may synergise in terms of their impact on the splicing machinery.
Conclusions
We have identified GALNS variants located within deep intronic regions that have the potential to impact splicing. These findings have prompted us to incorporate mRNA analysis into our diagnostic flow procedure for the molecular analysis of Morquio A disease
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Depth-resolved cathodoluminescence spectroscopy of silicon supersaturated with sulfur
We investigate the luminescence of Si supersaturated with S (Si:S) using depth-resolved cathodoluminescence spectroscopy and secondary ion mass spectroscopy as the S concentration is varied over 2 orders of magnitude . In single-crystalline supersaturated Si:S, we identify strong luminescence from intra-gap states related to Si self-interstitials and a S-related luminescence at 0.85 eV, both of which show a strong dependence on S concentration in the supersaturated regime. Sufficiently high S concentrations in Si result in complete luminescence quenching, which we propose is a consequence of the overlapping of the defect band and conduction band.Engineering and Applied Science
A search for radio afterglows from gamma-ray bursts with the Australian Square Kilometre Array Pathfinder
We present a search for radio afterglows from long gamma-ray bursts using the
Australian Square Kilometre Array Pathfinder (ASKAP). Our search used the Rapid
ASKAP Continuum Survey, covering the entire celestial sphere south of
declination , and three epochs of the Variables and Slow Transients
Pilot Survey (Phase 1), covering square degrees per epoch. The
observations we used from these surveys spanned a nine-month period from 2019
April 21 to 2020 January 11. We crossmatched radio sources found in these
surveys with 779 well-localised (to ) long gamma-ray bursts
occurring after 2004 and determined whether the associations were more likely
afterglow- or host-related through the analysis of optical images. In our
search, we detected one radio afterglow candidate associated with GRB 171205A,
a local low-luminosity gamma-ray burst with a supernova counterpart SN 2017iuk,
in an ASKAP observation 511 days post-burst. We confirmed this detection with
further observations of the radio afterglow using the Australia Telescope
Compact Array at 859 days and 884 days post-burst. Combining this data with
archival data from early-time radio observations, we showed the evolution of
the radio spectral energy distribution alone could reveal clear signatures of a
wind-like circumburst medium for the burst. Finally, we derived semi-analytical
estimates for the microphysical shock parameters of the burst: electron
power-law index , normalised wind-density parameter ,
fractional energy in electrons , and fractional energy in
magnetic fields .Comment: 18 pages, 7 figures; accepted for publication in MNRA
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