Don’t bring me down: People, puzzles, and social loafing

Identifiability (others knowing an individual’s effort) and social cohesion (personal attachment to a group) are both established influencers of social loafing (decreased effort when in a group). Much of the evidence indicates that identifiability and social cohesion are negatively correlated with social loafing. One hundred and sixty undergraduate students at a private northeast Ohio university participated in this experiment to examine the effect of identifiability and face-to-face contact on social loafing. There were independent groups of two variables: identifiability (yes or no) and group presence (present or absent). Participants worked on a puzzle for 15 minutes after which completed pieces were counted as the measure of effort. Results indicate there was no interaction between identifiability and presence of a group on social loafing and no significant main effect for either variable

A magnetar engine for short GRBs and kilonovae

We investigate the influence of magnetic fields on the evolution of binary neutron-star (BNS) merger remnants via three-dimensional (3D) dynamical-spacetime general-relativistic (GR) magnetohydrodynamic (MHD) simulations. We evolve a postmerger remnant with an initial poloidal magnetic field, resolve the magnetoturbulence driven by shear flows, and include a microphysical finite-temperature equation of state (EOS). A neutrino leakage scheme that captures the overall energetics and lepton number exchange is also included. We find that turbulence induced by the magnetorotational instability (MRI) in the hypermassive neutron star (HMNS) amplifies magnetic field to beyond magnetar-strength ($10^{15}\, \mathrm{G}$). The ultra-strong toroidal field is able to launch a relativistic jet from the HMNS. We also find a magnetized wind that ejects neutron-rich material with a rate of $\dot{M}_{\mathrm{ej}} \simeq 1 \times10^{-1}\, \mathrm{M_{\odot}\, s^{-1}}$. The total ejecta mass in our simulation is $5\times 10^{-3}\, \mathrm{M_{\odot}}$. This makes the ejecta from the HMNS an important component in BNS mergers and a promising source of $r$-process elements that can power a kilonova. The jet from the HMNS reaches a terminal Lorentz factor of $\sim 5$ in our highest-resolution simulation. The formation of this jet is aided by neutrino-cooling preventing the accretion disk from protruding into the polar region. As neutrino pair-annihilation and radiative processes in the jet (which were not included in the simulations) will boost the Lorentz factor in the jet further, our simulations demonstrate that magnetars formed in BNS mergers are a viable engine for short gamma-ray bursts (sGRBs).Comment: Resubmitted versio

Pharmacogenetics and individualizing drug treatment during pregnancy

Pharmacogenetics as a tool to aid clinicians implement individualized pharmacotherapy is utilized in some areas of medicine. Pharmacogenetics in pregnancy is still a developing field. However, there are several areas of obstetric therapeutics where data are emerging that give glimpses into future therapeutic possibilities. These include opioid pain management, antihypertensive therapy, antidepressant medications, preterm labor tocolytics, antenatal corticosteroids and drugs for nausea and vomiting of pregnancy, to name a few. More data are needed to populate the therapeutic models and to truly determine if pharmacogenetics will aid in individualizing pharmacotherapy in pregnancy. The objective of this review is to summarize current data and highlight research needs

The use of simultaneous chemical precipitation in modified activated sludge systems exhibiting biological enhanced phosphate removal

Includes bibliographies.Since its first full-scale implementation in the late 1970s, considerable practical experience has been gained with biological enhanced phosphate removal (BEPR) in activated sludge systems for treating wastewater. However, BEPR tends to be sensitive and subject to many fluctuations, making it difficult to achieve full compliance with discharge standards. Simultaneous chemical addition in the activated sludge systems is a practical and economically attractive means of increasing the phosphate (P) removal capacity of these systems. However, it is also clear that the economic benefit of building a BEPR system could be lost if simultaneous addition of chemicals results in significant inhibition of the biological P removal mechanism. In South Africa anecdotal evidence of such inhibition has emerged. In view of its fundamental importance to the design and operation of BEPR plants which incorporate simultaneous chemical addition, it was considered imperative that the impact of simultaneous chemical addition on the biological P removal mechanism be investigated further, particularly with a view to addressing possible outstanding questions arising from re-interpretation of earlier work. Experimental work was conducted using two identical pilot (or laboratory-scale) activated sludge plants operated such that the BEPR phenomenon was strongly exhibited. The two plants were operated in parallel under identical conditions. Chemical precipitant (aluminium sulphate, ferric chloride or ferrous chloride) was dosed into one plant (the Test unit), while the other served as Control. As a means of distinguishing the chemically-precipitated phosphate content of the mixed liquor from biologically-stored phosphate (or poly P) pool, methods for chemical fractionation of the phosphate compounds in activated sludge were investigated. A fractionation procedure was adopted which appeared to be capable of broadly distinguishing between chemical and biological forms of stored phosphorus in activated sludge and showed satisfactory agreement with the predicted results for BEPR obtained using a mathematical model of such systems. However, caution in interpretation of the fractionation data was advised since artefacts imposed by the fractionation procedure itself may be difficult to avoid