2,376 research outputs found
Opportunistic behaviour by private irrigators within a capacity-sharing regime
The concept of capacity-sharing (as a specific type of demand-orientated water management strategy) is a relatively newcomer on the South African water management regime and much debate is currently under way regarding the viability of the concept for the South African context. One of the main features is that it decentralises and integrates water management to a much greater degree than state-dominated management regimes. However, as the concept of capacity-sharing allows a greater degree of decision-making autonomy to the private decision-maker, the question could be asked to what extent the management of a capacity-sharing regime would be exposed to opportunistic behaviour from private irrigators. If it is heavily exposed, there are considerable scope for opportunistic decision-making behaviour under private decision-makers and therefore problems of moral hazard / adverse selection and rent seeking could present itself. Therefore, the question arises what safety features do capacity sharing present to confine possible opportunistic decision-making practices. This article discusses two areas within a capacity-sharing regime that are likely to be exposed to opportunistic decision-making behaviour. Possible safety-features from capacity sharing to account for this type of behaviour are identified and discussed briefly. This article concludes with the notion that capacity sharing does feature some properties that could minimise opportunistic behaviour from private decision-makers.Resource /Energy Economics and Policy,
Paying the price: why parties that turn their back on civil society face electoral upheaval
Political parties are increasingly confronted with high levels of electoral volatility. Nick Martin, Sarah de Lange and Wouter van der Brug write, however, that even in times of increased volatility, connections between party elites and organised civil society matter electorally. Drawing on a new study, they illustrate how these ties can help to stabilise the electorates of parties on both the left and right
Automated Jerboa Startling Device
ME450 Capstone Design and Manufacturing Experience: Winter 2021A hallway module that startles a jerboa with an air puff as well as a noise tone. It will then record the jerboa throughout the length of the hallway as well as take data from a force platform on the Jerboa.Talia Moore: Moore Biomechanicshttp://deepblue.lib.umich.edu/bitstream/2027.42/167640/1/Team_23-Automated_Jerboa_Startling_Device.pd
Reliability of computerized eye-tracking reaction time tests in non-athletes, athletes, and individuals with traumatic brain injury
Background: Eye tracking technologies and methodologies have advanced significantly in recent years. Specifically, the use of eye tracking to quantitatively measure oculomotor and psychophysiological constructs is gaining momentum. Reaction time has been measured in a number of different ways from a simple response to a stimulus to more challenging choice or discrimination responses to stimuli. Traditionally, reaction time is measured from the beginning of a stimulus event to a response event and includes both visual and motor response times. Eye tracking technology can provide a more discrete measurement of reaction time to include visual components such as visual latencies and visual speed, and can identify if the person was looking at the target area when a stimulus is presented. The aim of this paper was to examine the reliability of the simple reaction time, choice reaction time, and discriminate reaction time tests measured using eye tracking technology. Additionally, we sought to establish performance norms and examine gender differences in reaction time in the general population. A final objective was to conduct a preliminary comparison of reaction time measures across different populations including non-athletes, athletes, and individuals that had sustained a traumatic brain injury. Methods: A sample of 125 participants were recruited to undertake test-retest reliability, analysed using Cronbach’s alpha and intraclass correlation coefficients. A different data set of 1893 individuals, including athletes (n = 635), non-athletes (n = 627) and people with traumatic brain injury (n = 631) were compared using MANOVA to explore group differences in reaction time. Results: Results demonstrated that overall, the tests had good test-retest reliability. No significant differences were found for gender. Significant differences were found between groups with athletes performing best overall. Reaction times of people with traumatic brain injury were overall much more variable, showing very large standard deviations, than those of the non-athletes and athletes. Conclusions: Future research should consider the accuracy of eye movements and various demographic variables within groups
The cytoplasmic domain of the AAA+ protease FtsH is tilted with respect to the membrane to facilitate substrate entry
AAA+ proteases are degradation machines that use ATP hydrolysis to unfold protein substrates and translocate them through a central pore toward a degradation chamber. FtsH, a bacterial membrane-anchored AAA+ protease, plays a vital role in membrane protein quality control. How substrates reach the FtsH central pore is an open key question that is not resolved by the available atomic structures of cytoplasmic and periplasmic domains. In this work, we used both negative stain TEM and cryo-EM to determine 3D maps of the full-length Aquifex aeolicus FtsH protease. Unexpectedly, we observed that detergent solubilization induces the formation of fully active FtsH dodecamers, which consist of two FtsH hexamers in a single detergent micelle. The striking tilted conformation of the cytosolic domain in the FtsH dodecamer visualized by negative stain TEM suggests a lateral substrate entrance between the membrane and cytosolic domain. Such a substrate path was then resolved in the cryo-EM structure of the FtsH hexamer. By mapping the available structural information and structure predictions for the transmembrane helices to the amino acid sequence we identified a linker of ∼20 residues between the second transmembrane helix and the cytosolic domain. This unique polypeptide appears to be highly flexible and turned out to be essential for proper functioning of FtsH as its deletion fully eliminated the proteolytic activity of FtsH
The spread, treatment, and prevention of HIV-1: evolution of a global pandemic
The most up-to-date estimates demonstrate very heterogeneous spread of HIV-1, and more than 30 million people are now living with HIV-1 infection, most of them in sub-Saharan Africa. The efficiency of transmission of HIV-1 depends primarily on the concentration of the virus in the infectious host. Although treatment with antiviral agents has proven a very effective way to improve the health and survival of infected individuals, as we discuss here, the epidemic will continue to grow unless greatly improved prevention strategies can be developed and implemented. No prophylactic vaccine is on the horizon. However, several behavioral and structural strategies have made a difference — male circumcision provides substantial protection from sexually transmitted diseases, including HIV-1, and the application of antiretroviral agents for prevention holds great promise
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Leveraging population admixture to characterize the heritability of complex traits.
Despite recent progress on estimating the heritability explained by genotyped SNPs (h(2)g), a large gap between h(2)g and estimates of total narrow-sense heritability (h(2)) remains. Explanations for this gap include rare variants or upward bias in family-based estimates of h(2) due to shared environment or epistasis. We estimate h(2) from unrelated individuals in admixed populations by first estimating the heritability explained by local ancestry (h(2)γ). We show that h(2)γ = 2FSTCθ(1 - θ)h(2), where FSTC measures frequency differences between populations at causal loci and θ is the genome-wide ancestry proportion. Our approach is not susceptible to biases caused by epistasis or shared environment. We applied this approach to the analysis of 13 phenotypes in 21,497 African-American individuals from 3 cohorts. For height and body mass index (BMI), we obtained h(2) estimates of 0.55 ± 0.09 and 0.23 ± 0.06, respectively, which are larger than estimates of h(2)g in these and other data but smaller than family-based estimates of h(2)
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