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Impaired emotional processing is a core feature of schizophrenia (SZ). Consistent findings suggested that abnormal emotional processing in SZ could be paralleled by a disrupted functional and structural integrity within the fronto-limbic circuitry. The effective connectivity of emotional circuitry in SZ has never been explored in terms of causal relationship between brain regions. We used functional magnetic resonance imaging and Dynamic Causal Modeling (DCM) to characterize effective connectivity during implicit processing of affective stimuli in SZ.
We performed DCM to model connectivity between amygdala (Amy), dorsolateral prefrontal cortex (DLPFC), ventral prefrontal cortex (VPFC), fusiform gyrus (FG) and visual cortex (VC) in 25 patients with SZ and 29 HC. Bayesian Model Selection and average were performed to determine the optimal structural model and its parameters.
Analyses revealed that patients with SZ are characterized by a significant reduced top-down endogenous connectivity from DLPFC to Amy, an increased connectivity from Amy to VPFC and a decreased driving input to Amy of affective stimuli compared to HC. Furthermore, DLPFC to Amy connection in patients significantly influenced the severity of psychopathology as rated on Positive and Negative Syndrome Scale.
Results suggest a functional disconnection in brain network that contributes to the symptomatic outcome of the disorder. Our findings support the study of effective connectivity within cortico-limbic structures as a marker of severity and treatment efficacy in SZ.
Bipolar disorder (BD) is a severe, disabling and life-threatening illness. Disturbances in emotion and affective processing are core features of the disorder with affective instability being paralleled by mood-congruent biases in information processing that influence evaluative processes and social judgment. Several lines of evidence, coming from neuropsychological and imaging studies, suggest that disrupted neural connectivity could play a role in the mechanistic explanation of these cognitive and emotional symptoms. The aim of the present study is to investigate the effective connectivity in a sample of bipolar patients.
Dynamic causal modeling (DCM) technique was used to study 52 inpatients affected by bipolar disorders consecutively admitted to San Raffaele hospital in Milano and forty healthy subjects. A face-matching task was used as activation paradigm.
Patients with BD showed a significantly reduced endogenous connectivity in the DLPFC to Amy connection. There was no significant group effect upon the endogenous connection from Amy to ACC, from ACC to Amy and from DLPFC to ACC.
Both DLPFC and ACC are part of a network implicated in emotion regulation and share strong reciprocal connections with the amygdale. The pattern of abnormal or reduced connectivity between DLPFC and amygdala may reflect abnormal modulation of mood and emotion typical of bipolar patients.
Where two species occupy the same habitat and similar niches, competition is likely to drive small-scale spatial niche separation or resource partitioning that may not be immediately apparent. A stable isotope approach was used to investigate potential trophic niche separation between co-existing rocky shore crabs in the North-West (NW) Arabian Gulf. Leptodius exaratus and Pilumnopeus convexus which occupy similar shore height on the same rocky intertidal habitats. We also investigated conspecific differences between males vs females and adults vs juveniles. δ15N results indicated that adults of both species occupy a high trophic level in the rocky shore community, suggesting similar functional roles and potential for competition for food resources, while significant differences in δ13C values indicated differences in dietary sources between the two species, and also changes in diet between juveniles and adults in both species. MixSIAR analysis of δ15N and δ13C data confirmed field observations that both species are generalist omnivores, with potential for direct competition including adult predation on juveniles, including conspecifics. Differentiation in isotopic niches (SIBER analysis) was mainly driven by the significant differences in δ13C values, suggesting that co-existence of the two crab species is at least in part mediated by trophic niche separation or dietary resource partitioning, with some (unquantified) potential for spatial resource partitioning at the microhabitat level.
In this paper we construct an abelian category of mixed perverse sheaves attached to any realization of a Coxeter group, in terms of the associated Elias–Williamson diagrammatic category. This construction extends previous work of the first two authors, where we worked with parity complexes instead of diagrams, and we extend most of the properties known in this case to the general setting. As an application we prove that the split Grothendieck group of the Elias–Williamson diagrammatic category is isomorphic to the corresponding Hecke algebra, for any choice of realization.
This paper extends the resource-capability-based view in strategic management and discusses the capabilities for the firms to stay competitive in emerging economies. Faced with low levels of efficiency, technology, and skills, firms in emerging economies need to implement best management practices to overcome operational inefficiency while engage in innovation processes to address new opportunities. They have to develop the capabilities to enhance efficiency, the capabilities to undertake innovation, and the synthesis capabilities to combine the two to keep rivals at bay. The paper tests hypotheses against a data set of more than 20,000 firms from 36 emerging economies provided by the World Bank in 2012–2015 and finds strong evidence to support the arguments. The paper finds that the three sets of capabilities are positively related to productivity and, through it, financial performance.
Catechol-O-methyltransferase (COMT) inactivates catecholamines, Val/Val genotype was associated to an increased amygdala (Amy) response to negative stimuli and can influence the symptoms severity and the outcome of bipolar disorder, probably mediated by the COMT polymorphism (rs4680) interaction between cortical and subcortical dopaminergic neurotransmission. The aim of this study is to explore how rs4680 and implicit emotional processing of negative emotional stimuli could interact in affecting the Amy connectivity in bipolar depression. Forty-five BD patients (34 Met carriers vs. 11 Val/Val) underwent fMRI scanning during implicit processing of fearful and angry faces. We explore the effect of rs4680 on the strength of functional connectivity from the amygdalae to whole brain. Val/Val and Met carriers significantly differed for the connectivity between Amy and dorsolateral prefrontal cortex (DLPFC) and supramarginal gyrus. Val/Val patients showed a significant positive connectivity for all of these areas, where Met carriers presented a significant negative one for the connection between DLPFC and Amy. Our findings reveal a COMT genotype-dependent difference in corticolimbic connectivity during affective regulation, possibly identifying a neurobiological underpinning of clinical and prognostic outcome of BD. Specifically, a worse antidepressant recovery and clinical outcome previously detected in Val/Val patients could be associated to a specific increased sensitivity to negative emotional stimuli.
The common prawn (Palaemon serratus) supports a small-scale but economically important seasonal static-gear fishery in Cardigan Bay, Wales (UK). Due to a lack of statutory obligation and scientific evidence, the fishery has operated to date without any harvest-control rules that afford protection from overfishing. In response to fluctuations in landings and in pursuit of increased economic returns for their catch, some members of the fishing industry have adopted a size-selective harvesting regime, which we evaluate here using baseline data. Monthly samples were obtained from fishers operating out of five ports between October 2013 and May 2015 (N = 4233). All prawn were sexed, weighed and measured, whilst the fecundity of females was estimated for 273 (44%) individuals. Peak spawning occurred during the spring and females were estimated to undergo a ‘puberty moult’ at a carapace length (CL) of 7.7 mm, whilst functional maturity was estimated at a CL of 9.9 mm. The sampled population exhibited sexual dimorphism, with females attaining a greater size than males. The current harvesting regime results in a sex bias in landings as even large mature males remained under the recruitment size to the fishery, unlike the large mature females. The temporal trend in sex-ratio indicates a continual decrease in the catchability of female prawn through the fishing season; however, whether this is caused by depletion via fishing mortality or migratory behaviour is yet to be resolved. Here, we provide a comprehensive baseline evaluation of population biology and discuss the implications of our findings for fisheries management.
We present a review of our recent studies of Bias Temperature Instability (BTI) in Metal-Oxide-Semiconductor Field-Effect-Transistors (MOSFETs) fabricated with different material systems, highlighting the reliability opportunities and challenges of each novel device family. We discuss first the intrinsic reliability improvement offered by SiGe and Ge p-channel technologies, if a Si cap is used to passivate the channel, in order to fabricate a standard SiO2/HfO2 gate stack. We focus on SiGe gate stack optimizations for maximum BTI reliability, and on a simple physics-based model able to reproduce the experimental trends. This model framework is then used to understand the suboptimal BTI reliability and excessive time-dependent variability induced by oxide defect charging in different high-mobility channel gate stacks, such as Ge/GeOx/high-k and InGaAs/high-k. Finally we discuss how to pursue a reduction of charge trapping in alternative material systems in order to boost the device reliability and minimize time-dependent variability.
This paper reports an experiment to evaluate the effectiveness of repeated interactions in deterring leaders from using divide-and-conquer strategies to extract surplus from their subordinates, when every decision-maker involved is a group instead of an individual. We find that both the resistance rate by subordinates and the divide-and-conquer transgression rate by leaders are the same in the group and individual repeated coordinated resistance games. Similar to the individual game, adding communication to the group game can help deter opportunistic behavior by the leaders even in the presence of repetition.
The probabilistic solutions of the nonlinear stochastic dynamic (NSD) systems with polynomial type of nonlinearity are investigated with the subspace-EPC method. The space of the state variables of large-scale nonlinear stochastic dynamic system excited by white noises is separated into two subspaces. Both sides of the Fokker-Planck-Kolmogorov (FPK) equation corresponding to the NSD system is then integrated over one of the subspaces. The FPK equation for the joint probability density function of the state variables in another subspace is formulated. Therefore, the FPK equation in low dimensions is obtained from the original FPK equation in high dimensions and it makes the problem of obtaining the probabilistic solutions of large-scale NSD systems solvable with the exponential polynomial closure method. Examples about the NSD systems with polynomial type of nonlinearity are given to show the effectiveness of the subspace-EPC method in these cases.
To characterize the clinical outcomes of patients with bloodstream infection caused by carbapenem-resistant Acinetobacter baumannii during a 2-state monoclonal outbreak.
Multicenter observational study.
Four tertiary care hospitals and 1 long-term acute care hospital.
A retrospective medical chart review was conducted for all consecutive patients during the period January 1, 2005, through April 30, 2006, for whom 1 or more blood cultures yielded carbapenem-resistant A. baumannii.
We identified 86 patients from the 16-month study period. Their mortality rate was 41%; of the 35 patients who died, one-third (13) had positive blood culture results for carbapenem-resistant A. baumannii at the time of death. Risk factors associated with mortality were intensive care unit stay, malignancy, and presence of fever and/or hypotension at the time blood sample for culture was obtained. Only 5 patients received adequate empirical antibiotic treatment, but the choice of treatment did not affect mortality.
Fifty-seven patients (66.2%) had a single positive blood culture result for carbapenem-resistant A. baumannii; the only factor associated with a single positive blood culture result was the presence of decubitus ulcers. Interestingly, during the study period, a transition from single to multiple positive blood culture results was observed. Four patients, 3 of whom were in a burn intensive care unit, were bacteremic for more than 30 days (range, 36–86 days).
To our knowledge, this is the first time a study has described 2 patterns of bloodstream infection with A. baumannii: single versus multiple positive blood culture results, as well as a subset of patients with prolonged bacteremia.
Competition for coastal land use and overexploitation have reduced or degraded mangrove coverage throughout much of their distribution, especially in South-east Asia. Timber production was the initial motivation for early mangrove reforestation projects. More recently, benefits from protection against erosion and extreme weather events and direct improvements in livelihoods and food security are perceived as justifications for such restoration efforts. This study examines the socioeconomic impacts of a community-led reforestation project in the Philippines through a survey of the local fishers. Revenues from mangrove fisheries, tourism and timber result in an annual benefit to the community of US$ 315 ha−1 yr−1. This figure is likely to be considerably more if the contribution of the mangrove to the coastal catch of mangrove-associated species is included. This estimate only includes direct benefits to the community from mangroves, and not intangible benefits such as coastal protection, which paradoxically is perceived by the community as one of the most important functions. More than 90% of all fishers, regardless of where they fished, thought the mangrove provided protection from storms and typhoons and acted as a nursery site and should be protected. Those fishing only in the mangrove perceived more benefits from the mangrove and were prepared to pay more to protect it than those fishing outside. This study concludes that replanting mangroves can have a significant economic impact on the lives of coastal communities. Acknowledgement of the value of replanted mangroves compared with other coastal activities and the benefits they bring to the more economically-vulnerable coastal dwellers should support better informed policy and decision-making with regard to coastal habitat restoration.
Special Collections & Archives contains several important named theatre collections. Notable collections include the Arena Stage Collection, the Robert Breen / American National Theater and Academy Collection, and the Theater of the Thirties Collection. Used by researchers all over the world, these collections contain production notebooks, playbills, playscripts, photographs, scrapbooks, correspondence, and news clippings.
We first pay attention to the inflight charge state distribution
in a Pb ion beam propagating in a reactor-sized chamber delimited
by metallic walls. We thus compare Livermore (code BIC) and
Orsay (code BPIC) distributions in the presence of a residual
Flibe gas pressure. Next, we replace the electron plasma due
to Flibe ionization by a gliding plasma produced by the polarization
of the incoming ion beam on insulating walls. Corresponding electrons,
when attracted by the beam, are demonstrated to yield a very efficient
The numerical simulation of the driving beams in a heavy ion
fusion power plant is a challenging task, and simulation of
the power plant as a whole, or even of the driver, is not yet
possible. Despite the rapid progress in computer power, past
and anticipated, one must consider the use of the most advanced
numerical techniques, if we are to reach our goal expeditiously.
One of the difficulties of these simulations resides in the
disparity of scales, in time and in space, which must be resolved.
When these disparities are in distinctive zones of the simulation
region, a method which has proven to be effective in other areas
(e.g., fluid dynamics simulations) is the mesh refinement
technique. We discuss the challenges posed by the implementation
of this technique into plasma simulations (due to the presence
of particles and electromagnetic waves). We present the prospects
for and projected benefits of its application to heavy ion fusion,
in particular to the simulation of the ion source and the final
beam propagation in the chamber. A collaboration project is
under way at Lawrence Berkeley National Laboratory between the
Applied Numerical Algorithms Group (ANAG) and the Heavy Ion
Fusion group to couple the adaptive mesh refinement library
CHOMBO developed by the ANAG group to the particle-in-cell
accelerator code WARP developed by the Heavy Ion
Fusion–Virtual National Laboratory. We describe our progress
and present our initial findings.
This article presents analytical and simulation studies of
intense heavy ion beam propagation, including the injection,
acceleration, transport and compression phases, and beam transport
and focusing in background plasma in the target chamber. Analytical
theory and simulations that support the High Current Experiment
(HCX), the Neutralized Transport Experiment (NTX), and the advanced
injector development program, are being used to provide a basic
understanding of the nonlinear beam dynamics and collective
processes, and to develop design concepts for the next-step
Integrated Beam Experiment (IBX), an Integrated Research Experiment
(IRE), and a heavy ion fusion driver. Three-dimensional nonlinear
perturbative simulations have been applied to collective
instabilities driven by beam temperature anisotropy, and to
two-stream interactions between the beam ions and any unwanted
background electrons; three-dimensional particle-in-cell
simulations of the 2-MV electrostatic quadrupole (ESQ) injector
have clarified the influence of pulse rise time; analytical
studies and simulations of the drift compression process have
been carried out; syntheses of a four-dimensional particle
distribution function from phase-space projections have been
developed; and studies of the generation and trapping of stray
electrons in the beam self-fields have been performed.
Particle-in-cell simulations, involving preformed plasma, are
being used to study the influence of charge and current
neutralization on the focusing of the ion beam in NTX and in
a fusion chamber.
For the intense beams in heavy ion fusion accelerators, details
of the beam distribution as it emerges from the source region
can determine the beam behavior well downstream. This occurs
because collective space-charge modes excited as the beam is
born remain undamped for many focusing periods. Traditional
studies of the source region in particle beam systems have
emphasized the behavior of averaged beam characteristics, such
as total current, rms beam size, or emittance, rather than the
details of the full beam distribution function that are necessary
to predict the excitation of the collective modes. Simulations
of the beam in the source region and comparisons to experimental
measurements at Lawrence Berkeley National Laboratory and the
University of Maryland are presented to illustrate some of the
complexity in beam characteristics that has been uncovered as
increased attention has been devoted to developing a detailed
understanding of the source region. Also discussed are methods
of using the simulations to infer characteristics of the beam
distribution that can be difficult to measure directly.