222 research outputs found
Aerosol tests conducted at Aberdeen Proving Grounds MD.
Test data are reported that demonstrate the deposition from a spray dispersion system (Illinois Tool Works inductively charging rotary atomization nozzle) for application of decontamination solution to various surfaces in the passenger cabin of a Boeing 737 aircraft. The decontamination solution (EnviroTru) was tagged with a known concentration of fluorescein permitting determination of both airborne decontaminant concentration and surface deposited decontaminant solution so that the effective deposition rates and surface coverage could be determined and correlated with the amount of material sprayed. Six aerosol dispersion tests were conducted. In each test, aluminum foil deposition coupons were set out throughout the passenger area and the aerosol was dispersed. The aerosol concentration was measured with filter samplers as well as with optical techniques Average aerosol deposition ranged from 3 to 15 grams of decontamination solution per square meter. Some disagreement was observed between various instruments utilizing different measurement principles. These results demonstrate a potentially effective method to disperse decontaminant to interior surfaces of a passenger aircraft
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Stochastic Model of Tsc1 Lesions in Mouse Brain
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder due to mutations in either TSC1 or TSC2 that affects many organs with hamartomas and tumors. TSC-associated brain lesions include subependymal nodules, subependymal giant cell astrocytomas and tubers. Neurologic manifestations in TSC comprise a high frequency of mental retardation and developmental disorders including autism, as well as epilepsy. Here, we describe a new mouse model of TSC brain lesions in which complete loss of Tsc1 is achieved in multiple brain cell types in a stochastic pattern. Injection of an adeno-associated virus vector encoding Cre recombinase into the cerebral ventricles of mice homozygous for a Tsc1 conditional allele on the day of birth led to reduced survival, and pathologic findings of enlarged neurons, cortical heterotopias, subependymal nodules, and hydrocephalus. The severity of clinical and pathologic findings as well as survival was shown to be dependent upon the dose and serotype of Cre virus injected. Although several other models of TSC brain disease exist, this model is unique in that the pathology reflects a variety of TSC-associated lesions involving different numbers and types of cells. This model provides a valuable and unique addition for therapeutic assessment
Momentum dependent mean-field dynamics of compressed nuclear matter and neutron stars
Nuclear matter and compact neutron stars are studied in the framework of the
non-linear derivative (NLD) model which accounts for the momentum dependence of
relativistic mean-fields. The generalized form of the energy-momentum tensor is
derived which allows to consider different forms of the regulator functions in
the NLD Lagrangian. The thermodynamic consistency of the NLD model is
demonstrated for arbitrary choice of the regulator functions. The NLD approach
describes the bulk properties of the nuclear matter and compares well with
microscopic calculations and Dirac phenomenology. We further study the high
density domain of the nuclear equation of state (EoS) relevant for the matter
in -equilibrium inside neutron stars. It is shown that the low density
constraints imposed on the nuclear EoS and by the momentum dependence of the
Schr\"odinger-equivalent optical potential lead to a maximum mass of the
neutron stars around which accommodates the observed
mass of the J1614-2230 millisecond radio pulsar.Comment: 25 pages, 11 figures, accepted for publication in Nuclear Physics
Racism, anti-racist practice and social work: articulating the teaching and learning experiences of Black social workers
In the mid 1990s a Black practice teacher programme was established in Manchester and Merseyside with the primary aim to increase the number of Black practice teachers in social work organisations, and in turn provide a supportive and encouraging learning environment for Black student social workers whilst on placement. In the north‐west of England research has been undertaken, to establish the quality of the practice teaching and student learning taking place with Black practice teachers and students. This paper is an exploration of the ideas generated within the placement process that particularly focused on the discourse of racism and ant‐racist practice. Black students and practice teachers explain their understanding of racism and anti‐racist practice within social work. From the research, the paper will critique some of the ideas concerning anti‐racism. In particular, it will question whether anti‐racist social work practice needs to be re‐evaluated in the light of a context with new migrants, asylum seekers and refugees. It will concluded, by arguing that whilst the terms anti‐racism, Black and Minority Ethnic have resonance as a form of political strategic essentialism, it is important to develop more positive representations in the future
An experimental and numerical study of particle nucleation and growth during low-pressure thermal decomposition of silane
Abstract This paper discusses an experimental and numerical study of the nucleation and growth of particles during low-pressure (∼1:0 Torr) thermal decomposition of silane (SiH 4 ). A Particle Beam Mass Spectrometer was used to measure particle size distributions in a parallel-plate showerhead-type semiconductor reactor. An aerosol dynamics moment-type formulation coupled with a chemically reacting uid ow model was used to predict particle concentration, size, and transport in the reactor. Particle nucleation kinetics via a sequence of chemical clustering reactions among silicon hydride molecular clusters, growth by heterogeneous chemical reactions on particle surfaces and coagulation, and transport by convection, di usion, and thermophoresis were included in the model. The e ect of pressure, temperature, ow residence time, carrier gas, and silane concentration were examined under conditions typically used for low-pressure (∼1 Torr) thermal chemical vapor deposition of polysilicon. The numerical simulations predict that several pathways involving linear and polycyclic silicon hydride molecules result in formation of particle "nuclei," which subsequently grow by heterogeneous reactions on the particle surfaces. The model is in good agreement with observations for the pressure and temperature at which particle formation begins, particle sizes and growth rates, and relative particle concentrations at various process conditions. A simpliÿed, computationally inexpensive, quasi-coupled modeling approach is suggested as an engineering tool for process equipment design and contamination control during low-pressure thermal silicon deposition.
Experimental Study of the Shortest Reset Word of Random Automata
In this paper we describe an approach to finding the shortest reset word of a
finite synchronizing automaton by using a SAT solver. We use this approach to
perform an experimental study of the length of the shortest reset word of a
finite synchronizing automaton. The largest automata we considered had 100
states. The results of the experiments allow us to formulate a hypothesis that
the length of the shortest reset word of a random finite automaton with
states and 2 input letters with high probability is sublinear with respect to
and can be estimated as $1.95 n^{0.55}.
Nocturnal Oximetry-based Evaluation of Habitually Snoring Children
Rationale: The vast majority of children around the world
undergoing adenotonsillectomy for obstructive sleep
apnea–hypopnea syndrome (OSA) are not objectively diagnosed by
nocturnal polysomnography because of access availability and cost
issues. Automated analysis of nocturnal oximetry (nSpO2), which is
readily and globally available, could potentially provide a reliable and
convenient diagnostic approach for pediatric OSA.
Methods: DeidentifiednSpO2 recordings froma total of 4,191 children
originating from13 pediatric sleep laboratories around the worldwere
prospectively evaluated after developing and validating an automated
neural network algorithm using an initial set of single-channel nSpO2
recordings from 589 patients referred for suspected OSA.
Measurements and Main Results: The automatically
estimated apnea–hypopnea index (AHI) showed high
agreement with AHI from conventional polysomnography
(intraclass correlation coefficient, 0.785) when tested in 3,602
additional subjects. Further assessment on the widely used AHI
cutoff points of 1, 5, and 10 events/h revealed an incremental
diagnostic ability (75.2, 81.7, and 90.2% accuracy; 0.788, 0.854, and
0.913 area under the receiver operating characteristic curve,
respectively).
Conclusions: Neural network–based automated analyses of
nSpO2 recordings provide accurate identification of OSA
severity among habitually snoring children with a high pretest
probability of OSA. Thus, nocturnal oximetry may enable a
simple and effective diagnostic alternative to nocturnal
polysomnography, leading to more timely interventions and
potentially improved outcomes.Supported in part by project VA037 U16 from the Consejer´ıa de Educacio´ n de la Junta de Castilla y Leo´ n and the European Regional Development Fund (FEDER), project RTC-2015-3446-1 from the Ministerio de Econom´ıa y Competitividad and FEDER, and project 153/2015 of the Sociedad Espan˜ ola de Neumolog´ıa y Cirug´ıa Tora´ cica (SEPAR). L.K.-G. is supported by NIH grant 1R01HL130984. M.F.P. was supported by a Fellowship Educational grant award from the Kingdom of Saudi Arabia. D.´A. was in receipt of a Juan de la Cierva grant from the Ministerio de Econom´ıa y Competitividad. The funders played no role in the study design, data collection, data analysis, interpretation, and writing of the manuscript
Overweight, physical activity, tobacco and alcohol consumption in a cross-sectional random sample of German adults
BACKGROUND: There is a current paucity of data on the health behaviour of non-selected populations in Central Europe. Data on health behaviour were collected as part of the EMIL study which investigated the prevalence of infection with Echinococcus multilocularis and other medical conditions in an urban German population. METHODS: Participating in the present study were 2,187 adults (1,138 females [52.0%]; 1,049 males [48.0%], age: 18–65 years) taken from a sample of 4,000 persons randomly chosen from an urban population. Data on health behaviour like physical activity, tobacco and alcohol consumption were obtained by means of a questionnaire, documentation of anthropometric data, abdominal ultrasound and blood specimens for assessment of chemical parameters. RESULTS: The overall rate of participation was 62.8%. Of these, 50.3% of the adults were overweight or obese. The proportion of active tobacco smokers stood at 30.1%. Of those surveyed 38.9% did not participate in any physical activity. Less than 2 hours of leisure time physical activity per week was associated with female sex, higher BMI (Body Mass Index), smoking and no alcohol consumption. Participants consumed on average 12 grams of alcohol per day. Total cholesterol was in 62.0% (>5.2 mmol/l) and triglycerides were elevated in 20.5% (≥ 2.3 mmol/l) of subjects studied. Hepatic steatosis was identified in 27.4% of subjects and showed an association with male sex, higher BMI, higher age, higher total blood cholesterol, lower HDL, higher triglycerides and higher ALT. CONCLUSION: This random sample of German urban adults was characterised by a high prevalence of overweight and obesity. This and the pattern of alcohol consumption, smoking and physical activity can be considered to put this group at high risk for associated morbidity and underscore the urgent need for preventive measures aimed at reducing the significantly increased health risk
Nocturnal Oximetry-based Evaluation of Habitually Snoring Children
Rationale: The vast majority of children around the world
undergoing adenotonsillectomy for obstructive sleep
apnea–hypopnea syndrome (OSA) are not objectively diagnosed by
nocturnal polysomnography because of access availability and cost
issues. Automated analysis of nocturnal oximetry (nSpO2), which is
readily and globally available, could potentially provide a reliable and
convenient diagnostic approach for pediatric OSA.
Methods: DeidentifiednSpO2 recordings froma total of 4,191 children
originating from13 pediatric sleep laboratories around the worldwere
prospectively evaluated after developing and validating an automated
neural network algorithm using an initial set of single-channel nSpO2
recordings from 589 patients referred for suspected OSA.
Measurements and Main Results: The automatically
estimated apnea–hypopnea index (AHI) showed high
agreement with AHI from conventional polysomnography
(intraclass correlation coefficient, 0.785) when tested in 3,602
additional subjects. Further assessment on the widely used AHI
cutoff points of 1, 5, and 10 events/h revealed an incremental
diagnostic ability (75.2, 81.7, and 90.2% accuracy; 0.788, 0.854, and
0.913 area under the receiver operating characteristic curve,
respectively).
Conclusions: Neural network–based automated analyses of
nSpO2 recordings provide accurate identification of OSA
severity among habitually snoring children with a high pretest
probability of OSA. Thus, nocturnal oximetry may enable a
simple and effective diagnostic alternative to nocturnal
polysomnography, leading to more timely interventions and
potentially improved outcomes.Supported in part by project VA037 U16 from the Consejer´ıa de Educacio´ n de la Junta de Castilla y Leo´ n and the European Regional Development Fund (FEDER), project RTC-2015-3446-1 from the Ministerio de Econom´ıa y Competitividad and FEDER, and project 153/2015 of the Sociedad Espan˜ ola de Neumolog´ıa y Cirug´ıa Tora´ cica (SEPAR). L.K.-G. is supported by NIH grant 1R01HL130984. M.F.P. was supported by a Fellowship Educational grant award from the Kingdom of Saudi Arabia. D.´A. was in receipt of a Juan de la Cierva grant from the Ministerio de Econom´ıa y Competitividad. The funders played no role in the study design, data collection, data analysis, interpretation, and writing of the manuscript
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