2,964 research outputs found
Reconfigurable Flows and Defect Landscape of Confined Active Nematics
Using novel micro-printing techniques, we develop a versatile experimental
setup that allows us to study how lateral confinement tames the active flows
and defect properties of the microtubule/kinesin active nematic system. We
demonstrate that the active length scale that determines the self-organization
of this system in unconstrained geometries loses its relevance under strong
lateral confinement. Dramatic transitions are observed from chaotic to vortex
lattices and defect-free unidirectional flows. Defects, which determine the
active flow behavior, are created and annihilated on the channel walls rather
than in the bulk, and acquire a strong orientational order in narrow channels.
Their nucleation is governed by an instability whose wavelength is effectively
screened by the channel width. All these results are recovered in simulations,
and the comparison highlights the role of boundary conditions
Characterization of LR-115 Type 2 Detectors for Monitoring Indoor Radon 222: Determination of the Calibration Factor
The city of Lima, capital of Peru, has about 11 million inhabitants. Lima has no records about the indoor Radon 222 concentration levels in dwellings. Hereby, we are planning to register the indoor radon concentrations in Lima and in other cities of Peru in the next three years. First, we will determine the calibration factor for the detectors which will be used in our measurements. For this purpose, Solid State Nuclear Tracks Detectors of nitrocellulose nitrate (LR-115 type 2) were used.The calibration process using a Radium 226 source was described to obtain the calibration factor. Linear response in tracks number was found in relation with irradiation time and its stability after time at the calibration chamber
Pattern of Activated Pathways and Quality of Collateral Status in Patients with Symptomatic Internal Carotid Artery Occlusion
Background: Internal carotid artery occlusion (ICAO) is an important risk factor for stroke. Cerebral hemodynamics in patients with ICAO depends on the individual capacity to activate sufficient collateral pathways. Therefore, the assessment of intracranial collaterals is essential for the acute and long-term management of these patients and accurate estimation of further stroke risk.
Methods: Acute stroke patients with unilateral ICAO were prospectively enrolled. We assessed the following collaterals by transcranial color-coded sonography (TCCS): the anterior and posterior communicating artery (ACoA, PCoA), the ophthalmic artery (OA), and leptomeningeal collaterals of the posterior cerebral artery (LMC). We subdivided the flow pattern of the Doppler spectrum in the middle cerebral artery (MCA) into 3 categories: (1) good, (2) moderate, and (3) bad according to the hemodynamic effects on the ipsilateral MCA flow. Finally, we compared the individual TCCS results with the stroke pattern detected on CT or MRI scan.
Results: One hundred thirteen patients (age 66 +/- 12 years; female 24) were included. The collateral status was good, moderate, and bad in 59 (52%), 37 (33%), and 17 (15%) patients, respectively. The ACoA collateral was most frequently activated (81%), followed by the OA (63%), the PCoA (53%), and the LMC (22%). The quality of the collateral status was determined by the type (p = 0.0003) but not by the number (p = 0.19) of activated collateral pathways. Good collateral function was highly associated with primary collaterals (ACoA > PCoA). Best parameter for a good collateral status was an antegrade flow in the OA, indicating a high blood supply via the communicating arteries.
Conclusions: TCCS allows the assessment of intracranial collaterals and their hemodynamic capacity. Prevalence of collateral sufficiency in ICAO seems to be higher than previously reported. ACoA cross flow is essential for the optimal hemodynamic compensation of ICAO. Antegrade OA flow indicates good collateral status
Event-based modeling in temporal lobe epilepsy demonstrates progressive atrophy from cross-sectional data
Objective: Recent work has shown that people with common epilepsies have characteristic patterns of cortical thinning, and that these changes may be progressive over time. Leveraging a large multicenter cross-sectional cohort, we investigated whether regional morphometric changes occur in a sequential manner, and whether these changes in people with mesial temporal lobe epilepsy and hippocampal sclerosis (MTLE-HS) correlate with clinical features.
Methods: We extracted regional measures of cortical thickness, surface area, and subcortical brain volumes from T1-weighted (T1W) magnetic resonance imaging (MRI) scans collected by the ENIGMA-Epilepsy consortium, comprising 804 people with MTLE-HS and 1625 healthy controls from 25 centers. Features with a moderate case-control effect size (Cohen d ≥ .5) were used to train an event-based model (EBM), which estimates a sequence of disease-specific biomarker changes from cross-sectional data and assigns a biomarker-based fine-grained disease stage to individual patients. We tested for associations between EBM disease stage and duration of epilepsy, age at onset, and antiseizure medicine (ASM) resistance.
Results: In MTLE-HS, decrease in ipsilateral hippocampal volume along with increased asymmetry in hippocampal volume was followed by reduced thickness in neocortical regions, reduction in ipsilateral thalamus volume, and finally, increase in ipsilateral lateral ventricle volume. EBM stage was correlated with duration of illness (Spearman ρ = .293, p = 7.03 × 10-16 ), age at onset (ρ = -.18, p = 9.82 × 10-7 ), and ASM resistance (area under the curve = .59, p = .043, Mann-Whitney U test). However, associations were driven by cases assigned to EBM Stage 0, which represents MTLE-HS with mild or nondetectable abnormality on T1W MRI.
Significance: From cross-sectional MRI, we reconstructed a disease progression model that highlights a sequence of MRI changes that aligns with previous longitudinal studies. This model could be used to stage MTLE-HS subjects in other cohorts and help establish connections between imaging-based progression staging and clinical features.
Keywords: MTLE; disease progression; duration of illness; event-based model; patient staging
Constructivist Grounded Theory Approach in Understanding Couples’ Perceived Fairness of Gendered Division of Labor: Implications on Marxist Feminist Approach and Third Wave Feminist Thought
This study uses a constructivist Grounded Theory (GT) Approach guided by feminist and pro-feminism perspectives in developing a new model that analyzes the paradoxical question of why couples especially women perceive gendered division of labor as fair. Responses from agricultural partner dyads were subjected to the three-step method of the GT approach. Theoretical analysis revealed that perceived fairness of the gendered division of labor is grounded on the themes of (i) type of family upbringing, (ii) perceived physical advantage of men and perceived physical disadvantage of women, (iii) feelings of self-entitlement among men, (iv) role performance as indicator for self-worth among women, (v) sense of duty shared by the couple, (vi) open communication channels between couples, and (vii) observed family cooperation that entails delegation of household tasks to children. A new model illustrating the process of how gendered division of labor is regarded as fair between agricultural couples has been developed. Implications of this new model to Marxist Feminist Approach and Third Wave Feminism as basis for future social and policy reforms are also presented in this paper
The Sydney-AAO Multi-object Integral field spectrograph (SAMI)
We demonstrate a novel technology that combines the power of the multi-object
spectrograph with the spatial multiplex advantage of an integral field
spectrograph (IFS). The Sydney-AAO Multi-object IFS (SAMI) is a prototype
wide-field system at the Anglo-Australian Telescope (AAT) that allows 13
imaging fibre bundles ("hexabundles") to be deployed over a 1-degree diameter
field of view. Each hexabundle comprises 61 lightly-fused multimode fibres with
reduced cladding and yields a 75 percent filling factor. Each fibre core
diameter subtends 1.6 arcseconds on the sky and each hexabundle has a field of
view of 15 arcseconds diameter. The fibres are fed to the flexible AAOmega
double-beam spectrograph, which can be used at a range of spectral resolutions
(R=lambda/delta(lambda) ~ 1700-13000) over the optical spectrum (3700-9500A).
We present the first spectroscopic results obtained with SAMI for a sample of
galaxies at z~0.05. We discuss the prospects of implementing hexabundles at a
much higher multiplex over wider fields of view in order to carry out
spatially--resolved spectroscopic surveys of 10^4 to 10^5 galaxies.Comment: 24 pages, 16 figures. Accepted by MNRA
Decoherence and entanglement degradation of a qubit-qutrit system in non-inertial frames
We study the effect of decoherence on a qubit-qutrit system under the
influence of global, local and multilocal decoherence in non-inertial frames.
We show that the entanglement sudden death can be avoided in non-inertial
frames in the presence of amplitude damping, depolarizing and phase damping
channels. However, degradation of entanglement is seen due to Unruh effect. It
is shown that for lower level of decoherence, the depolarizing channel degrades
the entanglement more heavily as compared to the amplitude damping and phase
damping channels. However, for higher values of decoherence parameters,
amplitude damping channel heavily degrades the entanglement of the hybrid
system. Further more, no ESD is seen for any value of Rob's acceleration.Comment: 16 pages, 5 .eps figures, 1 table; Quantum Information Processing,
published online, 5 July, 201
Las comunidades terapéuticas como tratamiento para las drogodependencias: una revisión sistemática del seguimiento a corto plazo
Objetivo. Las comunidades terapéuticas (CT) constituyen uno de los tratamientos más extensos para las drogodependencias; sin embargo, su investigación es escasa. El objetivo fue realizar una revisión sistemática para conocer los elementos metodológicos de los estudios de seguimiento a corto plazo y, a su vez, describir las consecuencias de las CT. Material y método. Se aplicó el "Preferred Reporting Items for Systematic reviews and meta- Analyses" (PRISMA) para la búsqueda en Medline, PsycINFO, PsycARTICLES y PsycCRITIQUES de estudios de seguimiento a corto plazo de CT entre 1980 y 2010. Resultados. El seguimiento consiste en un registro inicial y, al menos, otro al medio año de tratamiento; la muestra mínima contiene 60 usuarios con una mayor prevalencia de hombres solteros;el 50% continúa en seguimiento y/o alcanza la abstinencia. Conclusión. Las CT parecen ser beneficiosas para el ajuste del consumo y otros aspectos psicosociales, aunque la falta de información dificulta garantizar la comparación de estos hallazgos. © 2013 Elsevier España, S.L. y SET. Todos los derechos reservados
WOU Community Health + Polk County COVID-19 Project: Campus-Community Partnership to Prevent Disease and Promote Community Well-Being During a Global Pandemic
The WOU Community Health + Polk County COVID-19 project is a local example of how Academic Health Departments can serve as public health training sites for students of public health and address the public health needs of the local community. An academic health department (AHD) represents a formal affiliation between an academic institution and a public health practice organization, such as a local health department. The WOU Community Health + Polk County COVID-19 project team consists of WOU faculty in Community Health, recent alumni, undergraduate students, and Polk County Public Health. This session will review the outcomes, challenges, and lessons learned from a one-year health communication and contact tracing intervention in Polk County, Oregon. How can undergraduate students, faculty, and community partners build a network for student success and community well-being? We share our publicly available health communication campaign materials and discuss students’ perspectives on professional development and networking opportunities within the project
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