43,280 research outputs found
Note On Endomorphism Algebras Of Separable Monoidal Functors
We recall the Tannaka construction for certain types of split monoidal
functor into Vect_{k}, and remove the compactness restriction on the domain
The thalamic reticular nucleus: a functional hub for thalamocortical network dysfunction in schizophrenia and a target for drug discovery
The thalamus (comprising many distinct nuclei) plays a key role in facilitating sensory discrimination and cognitive processes through connections with the cortex. Impaired thalamocortical processing has long been considered to be involved in schizophrenia. In this review we focus on the thalamic reticular nucleus (TRN) providing evidence for it being an important communication hub between the thalamus and cortex and how it may play a key role in the pathophysiology of schizophrenia. We first highlight the functional neuroanatomy, neurotransmitter localisation and physiology of the TRN. We then present evidence of the physiological roles of the TRN in relation to oscillatory activity, cognition and behaviour. Next we discuss the role of the TRN in rodent models of risk factors for schizophrenia (genetic and pharmacological) and provide evidence for TRN deficits in schizophrenia. Finally we discuss new drug targets for schizophrenia in relation to restoring TRN circuitry dysfunction
Binocular interactions underlying the classic optomotor responses of flying flies.
In response to imposed course deviations, the optomotor reactions of animals reduce motion blur and facilitate the maintenance of stable body posture. In flies, many anatomical and electrophysiological studies suggest that disparate motion cues stimulating the left and right eyes are not processed in isolation but rather are integrated in the brain to produce a cohesive panoramic percept. To investigate the strength of such inter-ocular interactions and their role in compensatory sensory-motor transformations, we utilize a virtual reality flight simulator to record wing and head optomotor reactions by tethered flying flies in response to imposed binocular rotation and monocular front-to-back and back-to-front motion. Within a narrow range of stimulus parameters that generates large contrast insensitive optomotor responses to binocular rotation, we find that responses to monocular front-to-back motion are larger than those to panoramic rotation, but are contrast sensitive. Conversely, responses to monocular back-to-front motion are slower than those to rotation and peak at the lowest tested contrast. Together our results suggest that optomotor responses to binocular rotation result from the influence of non-additive contralateral inhibitory as well as excitatory circuit interactions that serve to confer contrast insensitivity to flight behaviors influenced by rotatory optic flow
Supersymmetric Flavor-Changing Sum Rules as a Tool for b -> s gamma
The search for supersymmetry (SUSY) and other classes of new physics will be
tackled on two fronts, with high energy, direct detection machines, and in high
precision experiments searching for indirect signatures. While each of these
methods has its own strengths, even more can be gained by finding ways to
combine their results. In this paper, we examine one way of bridging these two
types of experiments by calculating sum rules which link physical squark masses
to the flavor-violating squark mixings. These sum rules are calculated for
minimally flavor-violating SUSY theories at both high and low tan(beta). We
also explore how the sum rules could help to disentangle the relative strengths
of different SUSY contributions to b -> s gamma, a favored channel for indirect
searches of new physics. Along the way, we show that the gluino contributions
to b -> s gamma can be very sizable at large tan(beta).Comment: 27 pages, 3 figure
Managing Option Fragility
We analyze and explore option fragility, the notion that option incentives are fragile due to their non-linear payoff structure. Option incentives become weaker as options fall underwater, leading to pressures to reprice options or restore incentives through additional grants of equity-based pay. We build a detailed data set on executives' portfolios of stock and options and find that executive options are frequently underwater, even when average stock returns have been high. For example, at the height of the bull market in 1999, approximately one-third of all executive options were underwater. We find that, in contrast to the incentives provided by stock, the incentives provided by options are quite sensitive to stock price changes, especially on the downside. Overall, we find that the incentives created by all executive holdings have an elasticity with respect to stock price decreases of about 0.7, and this elasticity is larger for high-option executives and for executives with high percentages of options already underwater. The dominant mechanism through which companies manage option fragility is larger option grants following stock price declines; on average, these larger grants restore approximately 40% of the stock-price-induced incentive declines. Option repricings are far less prevalent, despite the attention they have garnered. Interestingly, we find that for positive stock returns, higher returns lead to larger option grants, which raise incentives further. Thus, option grants are largest when companies do very poorly or very well. Executive exercising behavior also affects option fragility. Since executives are much less likely to exercise options following stock price decreases, the natural declines in incentives due to exercises are attenuated on the downside, leading executives to 'manage their own incentives' in a way that augments company management of option fragility.
Representation in the classroom: The effect of own-race teachers on student achievement
Previous research suggests that there are academic benefits when students and teachers share the same race/ethnicity because such teachers can serve as role models, mentors, advocates, or cultural translators. In this paper, we obtain estimates of achievement changes as students are assigned to teachers of different races/ethnicities from grades 3 through 10 utilizing a large administrative dataset provided by the Florida Department of Education that follows the universe of test-taking students in Florida public schools from 2001–2002 through 2008–2009. We find small but significant positive effects when black and white students are assigned to race-congruent teachers in reading (.004–.005 standard deviations) and for black, white and Asian/Pacific Island students in math (.007–.041 standard deviations). We also examine the effects of race matching by students' prior performance level, finding that lower-performing black and white students appear to particularly benefit from being assigned to a race-congruent teacher.http://sites.bu.edu/marcuswinters/files/2017/09/Egalite-et-al-2015-FLTM_EER.pdfAccepted manuscrip
Easy Come, EZ-GO: A Federal Role in Removing Jurisdictional Impediments to College Education
Outlines the need to raise college degree attainment by creating Educational Zone Governance Organizations in multistate metropolitan regions to coordinate and incentivize policies that expand access. Offers data by metro area, age, and race/ethnicity
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