2995 research outputs found
Sort by
Exposure of Canadian electronic waste dismantlers to flame retardants
No full textExposure of e-waste workers to eight halogenated and five organophosphate ester flame retardant chemicals (FRs) was studied at a Canadian e-waste dismantling facility. FR concentrations were measured in air and dust samples collected at a central location and at four work benches over five-24 hour periods spanning two weeks. The highest concentrations in air from workbenches were of BDE-209 (median 156 ng m), followed by Tris(2-chloroethyl) phosphate (TCEP, median 59 ng m). Dust concentrations at the workbenches were higher than those measured at the central location, consistent with the release of contaminated dust during dismantling. Dust concentrations from the workbenches were also dominated by BDE-209 (median 96,300 ng g), followed by Triphenyl phosphate (TPhP, median 47,000 ng g). Most FRs were in coarse particles 5.6–18 μm diameter and ~30% were in respirable particles (<~3 μm). Exposure estimates indicated that dust ingestion accounted for 63% of total FR exposure; inhalation and dermal absorption contributed 35 and 2%, respectively. Some air and dust concentrations as well as some estimated exposures in this formal facility in a high-income country exceeded those from informal e-waste facilities located in low and middle income countries. Although there is demonstrated toxicity of some FRs, FR exposure in the e-waste industry has received minimal attention and occupational limits do not exist for most FRs
Chronic stress produces enduring sex- and region-specific alterations in novel stress-induced c-Fos expression
No full textProlonged or repeated exposure to stress increases risk for a variety of psychological disorders, many of which are marked by dysfunction of corticolimbic brain regions. Notably, women are more likely than men to be diagnosed with these disorders, especially when onset of symptoms follows stressful life events. Using rodent models, investigators have recently begun to elucidate sex-specific changes in the brain and behavior that occur immediately following chronic stress. However, little is known regarding the lasting sequelae of chronic stress, as well as how potential changes may impact responsivity to future stressors. We recently demonstrated that male and female rats show different patterns of dendritic reorganization in medial prefrontal cortex in the days following chronic stress. Here, we examined the immediate and lasting effects of chronic restraint stress (CRS; 3 h/day, 10 days) on neuronal activation, across several corticolimbic brain regions, induced by novel acute stress exposure. Chronically stressed male and female rats were exposed to acute elevated platform stress (EPS) either 1 (CRS-EPS) or 7 (CRS-Rest-EPS) days after CRS. Compared to rats exposed to EPS only, significant reductions in acute stress-induced c-Fos expression were observed in the medial prefrontal cortex, hippocampus, and paraventricular nucleus of the hypothalamus (PVN) in CRS-EPS male rats, some of which persisted to 7 days post-stress. In contrast, we found little modulation of novel stress-induced c-Fos expression in CRS-EPS female rats. However, CRS-Rest-EPS female rats exhibited a significant enhancement of acute stress-induced neuronal activity in the PVN. Together, these data show that prior chronic stress produces sex- and region-specific alterations in novel stress-induced neuronal activation, which are dependent on the presence or absence of a rest period following chronic stress. These findings suggest that the post-stress rest period may give rise to sex-specific neuroadaptations to stress, which may underlie sex differences in stress susceptibility versus resilience
Adopting Text Mining on Rehabilitation Therapy Repositioning for Stroke
No full textStroke is a common disabling disease that severely affects the daily life of patients. Accumulating evidence indicates that rehabilitation therapy can improve movement function. However, no clear guidelines have specific and effective rehabilitation therapy schemes, and the development of new rehabilitation techniques has been relatively slow. This study used a text mining approach, the ABC model, to identify an existing rehabilitation candidate therapy method that is most likely to be repositioned for stroke. In the model, we built the internal links of stroke (A), assessment scales (B), and rehabilitation therapies (C) in PubMed and the links were related to upper limb function measurements for patients with stroke. In the first step, using E-utility, we retrieved both stroke-related assessment scales and rehabilitation therapy records and then compiled two datasets, which were called Stroke_Scales and Stroke_Therapies, respectively. In the next step, we crawled all rehabilitation therapies co-occurring with the Stroke_Therapies and then named them as All_Therapies. Therapies that were already included in Stroke_Therapies were deleted from All_Therapies; therefore, the remaining therapies were the potential rehabilitation therapies, which could be repositioned for stroke after subsequent filtration by a manual check. We identified the top-ranked repositioning rehabilitation therapy and subsequently examined its clinical validation. Hand-arm bimanual intensive training (HABIT) was ranked the first in our repositioning rehabilitation therapies and had the most interaction links with Stroke_Scales. HABIT significantly improved clinical scores on assessment scales [Fugl-Meyer Assessment (FMA) and action research arm test (ARAT)] in the clinical validation study for acute stroke patients with upper limb dysfunction. Therefore, based on the ABC model and clinical validation, HABIT is a promising repositioned rehabilitation therapy for stroke, and the ABC model is an effective text mining approach for rehabilitation therapy repositioning. The findings in this study would be helpful in clinical knowledge discovery
Observation of Excess Yield at Very Low Transverse Momenta in Au+Au Collisions at =200 GeV and U+ U Collisions at =193 GeV
No full textWe report on the first measurements of production at very low transverse momentum ( < 0.2 GeV/) in hadronic Au+Au collisions at = 200 GeV and U+U collisions at = 193 GeV. Remarkably, the inferred nuclear modification factor of at mid-rapidity in Au+Au (U+U) collisions reaches about 24 (52) for < 0.05 GeV/ in the 60-80% collision centrality class. This noteworthy enhancement cannot be explained by hadronic production accompanied by cold and hot medium effects. In addition, the distribution of for the very low range is presented for the first time. The distribution is consistent with that expected from the Au nucleus and shows a hint of interference. Comparison of the measurements to theoretical calculations of coherent production shows that the excess yield can be described reasonably well and reveals a partial disruption of coherent production in semi-central collisions, perhaps due to the violent hadronic interactions. Incorporating theoretical calculations, the results strongly suggest that the dramatic enhancement of yield observed at extremely low originates from coherent photon-nucleus interactions. In particular, coherently produced 's in violent hadronic collisions may provide a novel probe of the quark-gluon-plasma
Rest Evaluation for Active Concussion Treatment (ReAct) Protocol: a prospective cohort study of levels of physical and cognitive rest after youth sports-related concussion
No full textIntroduction: Although current guidelines for the early clinical management of sports-related concussion (SRC) call for a gradual return-to-activity, the optimal level of rest needed to promote recovery remains unknown. This paper describes the protocol of the Rest Evaluation for Active Concussion Treatment (ReAct) study which objectively measures physical and cognitive rest following SRC and its relation to recovery among youth athletes. Methods and analysis: Youth athletes aged 11–17 years are recruited preinjury and enrolled within 72 hours following a physician-diagnosed concussion. Injury information and acute clinical presentation are assessed at the time of injury. Youth participants are prospectively followed to objectively monitor daily physical and cognitive rest using two electronic devices: ActiGraph (to measure physical rest and sleep) and Narrative Clip (to measure cognitive rest), along with self-reported postconcussive symptoms using daily surveys. Other concussion outcomes, including functional outcomes, are assessed by surveying youth and their parents at three time points: (1) within 72 hours of injury, (2) at day 7 postenrolment and (3) at symptom resolution (or a maximum of 45 days postconcussion)
Bisect and Conquer: Hierarchical Clustering via Max-Uncut Bisection
No full textHierarchical Clustering is an unsupervised data analysis method which has been widely used for decades. Despite its popularity, it had an underdeveloped analytical foundation and to ad- dress this, Dasgupta recently introduced an optimization viewpoint of hierarchical clustering with pairwise similarity information that spurred a line of work shedding light on old algorithms (e.g., Average-Linkage), but also designing new algorithms. Here, for the maximization dual of Das- gupta’s objective (introduced by Moseley-Wang), we present polynomial-time .4246 approxima- tion algorithms that use Max-Uncut Bisection as a subroutine. The previous best worst-case approximation factor in polynomial time was .336, improving only slightly over Average-Linkage which achieves 1/3. Finally, we complement our positive results by providing APX-hardness (even for 0-1 similarities), under the Small Set Expansion hypothesis
Stable manifolds for a class of singular evolution equations and exponential decay of kinetic shocks
No full textWe construct stable manifolds for a class of singular evolution equations including the steady Boltzmann equation, establishing in the process exponential decay of associated kinetic shock and boundary layers to their limiting equilibrium states. Our analysis is from a classical dynamical systems point of view, but with a number of interesting modifications to accomodate ill-posedness with respect to the Cauchy problem of the underlying evolution equation
Diversity in Natural Transformation Frequencies and Regulation across Vibrio Species
No full textIn Vibrio species, chitin-induced natural transformation enables bacteria to take up DNA from the external environment and integrate it into their genome. Expression of the master competence regulator TfoX bypasses the need for chitin induction and drives expression of the genes required for competence in several Vibrio species. Here, we show that TfoX expression in Vibrio campbellii strains DS40M4 and NBRC 15631 enables high natural transformation frequencies. Conversely, transformation was not achieved in the model quorum-sensing strain V. campbellii BB120 (previously classified as Vibrio harveyi). Surprisingly, we find that quorum sensing is not required for transformation in V. campbellii DS40M4 or Vibrio parahaemolyticus in contrast to the established regulatory pathway in Vibrio cholerae in which quorum sensing is required to activate the competence regulator QstR. Similar to V. cholerae, expression of both QstR and TfoX is necessary for transformation in DS40M4. There is a wide disparity in transformation frequencies among even closely related Vibrio strains, with V. vulnificus having the lowest functional transformation frequency. Ectopic expression of both TfoX and QstR is sufficient to produce a significant increase in transformation frequency in Vibrio vulnificus. To explore differences in competence regulation, we used previously studied V. cholerae competence genes to inform a comparative genomics analysis coupled with transcriptomics. We find that transformation capability cannot necessarily be predicted by the level of gene conservation but rather correlates with competence gene expression following TfoX induction. Thus, we have uncovered notable species- and strain-level variations in the competence gene regulation pathway across the Vibrio genus
An Investigation into the Origin of Autopoiesis
Full text linkUsing a glider in the Game of Life cellular automaton as a toy model of minimal persistent individuals, this article explores how questions regarding the origin of life might be approached from the perspective of autopoiesis. Specifically, I examine how the density of gliders evolves over time from random initial conditions and then develop a statistical mechanics of gliders that explains this time evolution in terms of the processes of glider creation, persistence, and destruction that underlie it
American Abyss: Simulating a Modern American Civil War
Full text linkIn recent years, speculation has arisen in the United States about the possibility of a civil war. Here I introduce a paper simulation of such a war using state-of-the-art lessons about modern civil war that have been developed within the diplomatic/military/intelligence conflict simulation community. According to those lessons, counter-insurgency (COIN) operations are a beastly mess for everyone involved. The simulation allows players to see why: In a modern intra-state conflict, there are many actors at play, each with their own access to the critical resources of media, money, and arms. These actors all have asymmetric aims, which lead to constantly shifting loyalties. The result is a conflict that is unlikely to end until all of the players are completely exhausted. I developed the simulation described in this paper as a warning to those who want to take up arms: Do not