5,249 research outputs found
Application of pulsed UV-irradiation and pre-coagulation to control ultrafiltration membrane fouling in the treatment of micro-polluted surface water.
A major cause of ultrafiltration (UF) membrane fouling is the accumulation of microorganisms and their associated soluble products. To mitigate fouling the application of pulsed short-wavelength ultraviolet (UVC) light (around 254Ā nm) within the membrane tank together with pre-coagulation was investigated. In mini-pilot-scale tests carried out in parallel with conventional pre-treatment (CUF), the impact of pulsed UV (CUF-UV) at different UV irradiances and fluxes on the increase of trans-membrane pressure (TMP) was evaluated and explained in terms of the quantity and nature of membrane deposits in the membrane cake layer and pores. The results indicated that at a flux of 20Ā LĀ m(-2)Ā h(-1), the pulsed UV (1Ā min within 31Ā min cycle) at 3.17Ā ĆĀ 10(-2)Ā W/cm(2) prevented any measureable increase in TMP over a period of 32 days, while there was a fourfold increase in TMP for the conventional pre-treatment. For the CUF-UV system the concentration of bacteria and soluble microbial products was much less than the conventional CUF system, and the cake layer was thinner and contained less biopolymers (proteins and polysaccharides). In addition, the pores of the CUF-UV membrane appeared to have less organic deposits, and particularly fractions with a high molecular weight (>10Ā kDa). At a lower UV irradiance (1.08Ā ĆĀ 10(-2)Ā W/cm(2)), or higher flux (40Ā LĀ m(-2)Ā h(-1)) with the same UV irradiance, there was a measurable increase in TMP, indicating some fouling of the CUF-UV membrane, but the rate of TMP development was significantly lower (ā¼50%) than the conventional CUF membrane system. Overall, the results show the potential advantages of applying intermittent (pulsed) UVC irradiation with coagulation to control UF membrane fouling
Temporal-spatial analysis of severe acute respiratory syndrome among hospital inpatients
Background. We report the temporal-spatial spread of severe acute respiratory syndrome (SARS) among inpatients in a hospital ward during a major nosocomial outbreak and discuss possible mechanisms for the outbreak. Methods. All inpatients who had stayed in the same ward as the initial index case patient for any duration before isolation were recruited into a cohort and followed up to document the occurrence of SARS. The normalized concentration of virus-laden aerosols at different locations of the ward was estimated by use of computational fluid dynamics modeling. The attack rates in the various subgroups stratified by bed location were calculated. Multivariate Cox proportional hazards regression was used to document important risk factors. Results. The overall attack rate of SARS was 41% (30 of 74 subjects). It was 65%, 52%, and 18% in the same bay, adjacent bay, and distant bays, respectively (P = .001). Computation fluid dynamics modeling indicated that the normalized concentration of virus-laden aerosols was highest in the same bay and lowest in the distant bays. Cox regression indicated that staying in the ward on 6 or 10 March entailed higher risk, as well as staying in the same or adjacent bays. The epidemic curve showed 2 peaks, and stratified analyses by bed location suggested >1 generation of spread. Conclusions. The temporal-spatial spread of SARS in the ward was consistent with airborne transmission, as modeled by use of computational fluid dynamics. Infected health care workers likely acted as secondary sources in the latter phase of the outbreak. Ā© 2005 by the Infectious Diseases Society of America. All rights reserved.published_or_final_versio
Risks for heart disease and lung cancer from passive smoking by workers in the catering industry
Workers in the catering industry are at greater risk of exposure to secondhand smoke (SHS) when smoke-free workplace policies are not in force. We determined the exposure of catering workers to SHS in Hong Kong and their risk of death from heart disease and lung cancer. Nonsmoking catering workers were provided with screening at their workplaces and at a central clinic. Participants reported workplace, home, and leisure time exposure to SHS. Urinary cotinine was estimated by enzyme immunoassay. Catering facilities were classified into three types: nonsmoking, partially restricted smoking (with nonsmoking areas), and unrestricted smoking. Mean urinary cotinine levels ranged from 3.3 ng/ml in a control group of 16 university staff through 6.4 ng/ml (nonsmoking), 6.1 ng/ml (partially restricted), and 15.9 ng/ml (unrestricted smoking) in 104 workers who had no exposures outside of work. Workers in nonsmoking facilities had exposures to other smoking staff. We modeled workers' mortality risks using average cotinine levels, estimates of workplace respirable particulates, risk data for cancer and heart disease from cohort studies, and national (US) and regional (Hong Kong) mortality for heart disease and lung cancer. We estimated that deaths in the Hong Kong catering workforce of 200,000 occur at the rate of 150 per year for a 40-year working-lifetime exposure to SHS. When compared with the current outdoor air quality standards for particulates in Hong Kong, 30% of workers exceeded the 24-h and 98% exceeded the annual air quality objectives due to workplace SHS exposures. Ā© 2006 Oxford University Press.postprin
A contextualizaĆ§Ć£o como estruturante curricular na educaĆ§Ć£o em ciĆŖncias : uma discussĆ£o a partir dos documentos oficiaisbra sileiros e artigos especializados
As Diretrizes e Bases da EducaĆ§Ć£o Nacional desencadearam polĆticas educacionais para a redefiniĆ§Ć£o do Ensino MĆ©dio no Brasil. Como parte dessa polĆtica, os ParĆ¢metros Curriculares Nacionais incorporam a contextualizaĆ§Ć£o como princĆpio curricular central. Empregando anĆ”lise de conteĆŗdo,analisamos artigos de periĆ³dicos que atribuem diferentes sentidos para a contextualizaĆ§Ć£o no Ensino de CiĆŖncias. Com a construĆ§Ć£o de categorias inspiradas na anĆ”lise vigotskiana, dimensionamos o conteĆŗdo da contextualizaĆ§Ć£o como sentido epistemolĆ³gico/cognitivo, Ć©tico e hĆbridos destes dois.Encontramos a preponderĆ¢ncia de um hibridismo entre uma contextualizaĆ§Ć£o que busca dar um sentido cognitivo ao conhecimento e uma contextualizaĆ§Ć£o que busca um sentido Ć©tico, articulaĆ§Ć£o nem sempre presentes de forma explicita nos documentos oficiais
Assessing architectural evolution: A case study
This is the post-print version of the Article. The official published can be accessed from the link below - Copyright @ 2011 SpringerThis paper proposes to use a historical perspective on generic laws, principles,
and guidelines, like Lehmanās software evolution laws and Martinās design principles, in order to achieve a multi-faceted process and structural assessment of a systemās architectural evolution. We present a simple structural model with associated historical metrics and
visualizations that could form part of an architectās dashboard. We perform such an assessment for the Eclipse SDK, as a case study of a large, complex, and long-lived system for which sustained effective architectural evolution is paramount. The twofold aim of checking generic principles on a well-know system is, on the one hand,
to see whether there are certain lessons that could be learned for best practice of architectural evolution, and on the other hand to get more insights about the applicability of such principles. We find that while the Eclipse SDK does follow several of the laws and principles, there are some deviations, and we discuss areas of architectural improvement and limitations of the assessment approach
Linguistic Structure Guided Context Modeling for Referring Image Segmentation
Referring image segmentation aims to predict the foreground mask of the
object referred by a natural language sentence. Multimodal context of the
sentence is crucial to distinguish the referent from the background. Existing
methods either insufficiently or redundantly model the multimodal context. To
tackle this problem, we propose a "gather-propagate-distribute" scheme to model
multimodal context by cross-modal interaction and implement this scheme as a
novel Linguistic Structure guided Context Modeling (LSCM) module. Our LSCM
module builds a Dependency Parsing Tree suppressed Word Graph (DPT-WG) which
guides all the words to include valid multimodal context of the sentence while
excluding disturbing ones through three steps over the multimodal feature,
i.e., gathering, constrained propagation and distributing. Extensive
experiments on four benchmarks demonstrate that our method outperforms all the
previous state-of-the-arts.Comment: Accepted by ECCV 2020. Code is available at
https://github.com/spyflying/LSCM-Refse
Self-rated health in middle-aged and elderly Chinese : distribution, determinants and associations with cardio-metabolic risk factors
Background: Self-rated health (SRH) has been demonstrated to be an accurate reflection of a person's health and a valid predictor of incident mortality and chronic morbidity. We aimed to evaluate the distribution and factors associated with SRH and its association with biomarkers of cardio-metabolic diseases among middle-aged and elderly Chinese.
Methods: Survey of 1,458 men and 1,831 women aged 50 to 70 years, conducted in one urban and two rural areas of Beijing and Shanghai in 2005. SRH status was measured and categorized as good (very good and good) vs. not good (fair, poor and very poor). Determinants of SRH and associations with biomarkers of cardio-metabolic diseases were evaluated using logistic regression.
Results: Thirty two percent of participants reported good SRH. Males and rural residents tended to report good SRH. After adjusting for potential confounders, residence, physical activity, employment status, sleep quality and presence of diabetes, cardiovascular disease, and depression were the main determinants of SRH. Those free from cardiovascular disease (OR 3.68; 95%CI 2.39; 5.66), rural residents (OR 1.89; 95% CI 1.47; 2.43), non-depressed participants (OR 2.50; 95% CI 1.67; 3.73) and those with good sleep quality (OR 2.95; 95% CI 2.22; 3.91) had almost twice or over the chance of reporting good SRH compared to their counterparts. There were significant associations -and trend- between SRH and levels of inflammatory markers, insulin levels and insulin resistance.
Conclusion: Only one third of middle-aged and elderly Chinese assessed their health status as good or very good. Although further longitudinal studies are required to confirm our findings, interventions targeting social inequalities, lifestyle patterns might not only contribute to prevent chronic morbidity but as well to improve populations' perceived health
Outlier Edge Detection Using Random Graph Generation Models and Applications
Outliers are samples that are generated by different mechanisms from other
normal data samples. Graphs, in particular social network graphs, may contain
nodes and edges that are made by scammers, malicious programs or mistakenly by
normal users. Detecting outlier nodes and edges is important for data mining
and graph analytics. However, previous research in the field has merely focused
on detecting outlier nodes. In this article, we study the properties of edges
and propose outlier edge detection algorithms using two random graph generation
models. We found that the edge-ego-network, which can be defined as the induced
graph that contains two end nodes of an edge, their neighboring nodes and the
edges that link these nodes, contains critical information to detect outlier
edges. We evaluated the proposed algorithms by injecting outlier edges into
some real-world graph data. Experiment results show that the proposed
algorithms can effectively detect outlier edges. In particular, the algorithm
based on the Preferential Attachment Random Graph Generation model consistently
gives good performance regardless of the test graph data. Further more, the
proposed algorithms are not limited in the area of outlier edge detection. We
demonstrate three different applications that benefit from the proposed
algorithms: 1) a preprocessing tool that improves the performance of graph
clustering algorithms; 2) an outlier node detection algorithm; and 3) a novel
noisy data clustering algorithm. These applications show the great potential of
the proposed outlier edge detection techniques.Comment: 14 pages, 5 figures, journal pape
Effect of Body Mass Index on pregnancy outcomes in nulliparous women delivering singleton babies
Peer reviewedPublisher PD
Existence, uniqueness and structure of second order absolute minimisers
Let ā Rn be a bounded open C1,1 set. In this paper we prove the existence
of a unique second order absolute minimiser uā of the functional
Eā(u, O) := F(Ā·, u)Lā(O), O ā measurable,
with prescribed boundary conditions for u and Du on ā and under natural assumptions
on F. We also show that uā is partially smooth and there exists a harmonic
function fā ā L1() such that
F(x, uā(x)) = eā sgn
fā(x)
for all x ā { fā = 0}, where eā is the infimum of the global energy
- ā¦