877 research outputs found

    Non-assimilated tidal modeling of the South China Sea

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    AbstractThe tides in the South China Sea were simulated using an established tidal model, with the purpose to evaluate if non-assimilated modeling of the area is feasible. Simulations were done for the locally dominating diurnal (K1) and semi-diurnal (M2) tidal constituents, and the model was shown to provide reasonably accurate results in terms of both elevations and levels of dissipation. However, this was only the case when a realistic tidal conversion parameterization was included in the model, and it is suggested that tidal conversion is a missing process in other model efforts of the area. Compared to observations, the modeled dissipation levels were slightly overestimated when integrated over the entire domain, and far larger in the model at topography with a slope which is supercritical for the baroclinic tidal waves. A crude, empirical correction of the tidal conversion rates at supercritical topography is suggested and implemented in the model and shown to improve the model results in terms of both elevations and dissipation rates. It is concluded that the presented model set up is suitable for investigations of how perturbations, e.g., future sea-level rise, will affect the tidal dynamics in the South China Sea

    ANTIBACTERIAL PROPERTIES AND DRYING EFFECTS OF FLAX DENIM AND ANTIBACTERIAL PROPERTIES OF NONWOVEN FLAX FABRIC

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    A modification of “AATCC Test Method 100-1999” was used for assaying for bacteriostatic/antibacterial properties of denim containing various flax concentrations. Since no direct evidence that increasing the flax content of fabric imparted the fabric with increased bacteriostatic properties was found against the control bacteria, Staphylococcus aureus and Klebsiella pneumoniae, other possible explanations for the long held presumption that flax fabric exhibited antibacterial properties was sought. Because the appearance of having antibacterial or bacteriostatic properties might be imitated if the flax content would decrease the time fabric would be moist enough for bacterial growth, the effect of drying was evaluated. When flax fabric was saturated and the moisture lost during incubation was measured, there was no improved drying associated with increased flax content. When untreated nonwoven flax was evaluated as possibly containing more ‘antibacterial’ or bacteriostatic components than scoured nonwoven flax material, the population densities increased. This increase suggests that the unscoured nonwoven flax contain compo-nents that support bacterial growth to the extent that bacteriostatic or antibacterial components, if any, are overwhelmed by the components that support bacterial growth. In tests involving the control bacteria, Staphylococcus aureus and Klebsiella pneumoniae, increasing the flax content of flax fabric did not demonstrate increased antibacterial properties

    Discovery learning approach to classic electrical machines principles

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    This paper aims at presenting the concept of Socratic interactions and discovery learning of classic electrical machines principles. The theories of electrical machines are by nature quite boring and abstract although there are a lot of experiments supported the theories. Traditional, students learnt the subject by drill and practice approach with standard textbooks. In the past two decades, computer is no doubt recognized to be the educational tool. The so-called “interactive” approach is applied to the learning process. Most of this approach applied to various subjects in different levels is mainly based on drill and practice. However, few packages are developed for electrical machine subject. In this paper, two different approaches “Rote Learning” and “Discovery Learning” applied to the interactive computer aided learning package of classic electric machine principles are discussed. Design of a discovery learning approach will also be presented

    Reliability and Validity of a Hong Kong Chinese Version of the St George's Respiratory Questionnaire in Patients with COPD

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    AbstractThe St George's Respiratory Questionnaire (SGRQ) is a self-administered questionnaire designed to measure quality of life (QOL) covering three areas (symptoms, activity and impacts) in patients with chronic obstructive pulmonary disease (COPD). The aim of the present study was to develop a Chinese version of the SGRQ (SGRQ-HK) and assess its psychometric properties. A forward and back-translation method was used, which included professional and lay people. Psychometric and clinical evaluations included 54 patients with COPD (31 males: mean age, 71.22 ± 5.95 years; 23 females: mean age, 68.8 ± 8.64 years). An additional QOL questionnaire and clinical and physiological data were also collected. The correlation coefficient between “symptoms” and dyspnoea was 0.67, that between “activity” and the 6-minute walk test was −0.78, between “impacts” and “mental health” of the SF-36 Health Survey Mental Health Inventory was −0.62; and between “total” and “general health” of the SF-36 was −0.87. Cronbach's a ranged from 0.74 to 0.95 for the whole questionnaire and its three subscales. Test-retest reliability showed intraclass correlation coefficients of all the dimensions exceeding 0.70. The three-factor structure of the SGRQ-HK was established. In conclusion, the SGRQ-HK is reliable and valid and compares well with the original English version

    Molecular cloning and chromosomal localization of a novel Drosophila protein phosphatase

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    AbstractA 1.0 kilobase cDNA coding for the complete amino acid sequence of a putative protein phosphatase (314 amino acid residues, molecular mass 36 kDa) has been isolated from a Drosophila head cDNA library. The cDNA hybridises to a single site on the right arm of the second chromosome at cytological position 55A1–3. The deduced sequence of the protein, designated protein phosphatase-Y, is homologous to the catalytic subunits of Drosophila and rabbit protein phosphatase- 1α (64 and 59% identity, respectively) and rabbit protein phosphatase-2A (39% identity). These and other comparisons demonstrate that this novel enzyme is not the Drosophila counterpart of mammalian protein phosphatases 1, 2A, 2B, 2C or X

    The Relationship Between Consumption of Beverages and Tooth Wear Among Adults in The United States

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    Objectives: To investigate the prevalence and severity of tooth wear (TW) and its relationship with consumption of beverages among adults in the United States. Methods: The National Health and Nutrition Examinations Survey data for 2003-2004 was analyzed. TW was defined as “wear on at least one surface of at least one examined tooth.” Drink/juice consumption was ascertained via a Food Frequency Questionnaire processed with Diet*Calc software to obtain the average daily consumption frequency for all queried drinks and juice categories including milk. Survey-weighted descriptive and multivariable analyses with interaction terms were performed. Results: Our study sample consisted of 3,773 adults (aged 20 and above). Eighty percent of the subjects had evidence of TW, and soft drinks were the most consumed beverage. Significant interactions between the effects of age, gender, and race/ethnicity on TW were found (P \u3c  0.001). After adjustment for demographic factors, consumption of fruit drinks was found to be significantly associated with the severity [odds ratio (OR) = 1.32 and 1.42], but not prevalence of TW. However, this trend was reversed for grape juice consumption (OR = 0.34, 0.41). Conclusions: This study demonstrates that a substantial proportion of adults had evidence of TW, which was affected by demographic factors in a complex way. Fruit drinks consumption in adults was associated with the severity of TW, but not with the prevalence of TW after adjusting for demographics. These findings are important for the development of appropriate treatment guidelines, public policy, and programs aimed at reducing TW in adults

    Disruption of marine habitats by artificial light at night from global coastal megacities

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    Half of globally significant megacities are situated near the coast, exposing urban marine ecosystems to multiple stressors such as waste-water discharge containing a host of organic and inorganic pollutants, air and noise pollution. In addition to these well recognized sources, artificial light at night (ALAN) pollution is inseparable from cities but poorly quantified in marine ecosystems to date. We have developed a time- and wavelength-resolving hydrological optical model that includes solar (daylight and twilight components), lunar and ALAN source terms and propagates these spectrally through a tidally varying water column using Beer’s Law. Our model shows that for 8 globally distributed cities surface ALAN dosages are up to a factor of 6 greater than moonlight, as ALAN intensities vary little throughout the night, over monthly or seasonal cycles. Moonlight only exceeds ALAN irradiances over the ±3-day period around full moon, and particularly during the brightest moons (mid-latitude winter, at zenith). Unlike the relatively stable surface ALAN, underwater ALAN varies spectrally and in magnitude throughout the night due to tidal cycles. The extent of ALAN in-water attenuation is location-specific, driven by the season, tidal range and cycle, and water clarity. This work highlights that marine ALAN ecosystem pollution is a particularly acute global change issue near some of the largest cities in the world

    A model problem for conformal parameterizations of the Einstein constraint equations

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    We investigate the possibility that the conformal and conformal thin sandwich (CTS) methods can be used to parameterize the set of solutions of the vacuum Einstein constraint equations. To this end we develop a model problem obtained by taking the quotient of certain symmetric data on conformally flat tori. Specializing the model problem to a three-parameter family of conformal data we observe a number of new phenomena for the conformal and CTS methods. Within this family, we obtain a general existence theorem so long as the mean curvature does not change sign. When the mean curvature changes sign, we find that for certain data solutions exist if and only if the transverse-traceless tensor is sufficiently small. When such solutions exist, there are generically more than one. Moreover, the theory for mean curvatures changing sign is shown to be extremely sensitive with respect to the value of a coupling constant in the Einstein constraint equations.Comment: 40 pages, 4 figure

    Reference on copy number variations in pleomorphic xanthoastrocytoma: Implications for diagnostic approach

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    Pleomorphic xanthoastrocytoma (PXA) poses a diagnostic challenge. The present study relies on methylation-based predictions and focuses on copy number variations (CNV) in PXA. We identified 551 tumors from patients having received the histologic diagnosis or differential diagnosis pleomorphic xanthoastrocytoma (PXA) uploaded to the web page www.molecularneuropathology.org. Of these 551 tumors, 165 received the prediction “methylation class (anaplastic) pleomorphic xanthoastrocytoma” with a calibrated score >=0.9 by the brain tumor classifier version v12.8 and, therefore, were defined the PXA reference set designated mcPXAref. In addition to these 165 mcPXAref, 767 other tumors received the prediction mcPXA with a calibrated score >=0.9 but without a histological PXA diagnosis. The total number of individual tumors predicted by histology and/or by methylome based classification as PXA, mcPXA or both was 1318, and these were designated the study cohort. The selection of a control cohort was guided by methylation-based predictions recurrently observed for the other 386/551 tumors diagnosed as histologic PXA. 131/386 received predictions for another entity besides PXA with a score >=0.9. Control tumors corresponding to the 11 most common other predictions were selected, adding up to 1100 reference cases. CNV profiles were calculated from all methylation datasets of the study and control cohorts. Special attention was given to the 7/10 signature, gene amplifications and homozygous deletion of CDKN2A/B. Comparison of CNV in the subsets of the study cohort and the control cohort were used to establish relations independent of histological diagnoses. Tumors in mcPXA were highly homogenous in regard to CNV alterations, irrespective of the histological diagnoses. The 7/10 signature commonly present in glioblastoma, IDH-wildtype, was present in 15-20% of mcPXA, whereas amplification of oncogenes (likewise common in glioblastoma) was very rare in mcPXA (<1%). In contrast, the histology-based PXA group exhibited high variance in regard to methylation classes as well as to CNVs. Our data add to the notion, that histologically defined PXA likely only represent a subset of the biological disease

    Expression of proadrenomedullin derived peptides in the mammalian pituitary: co-localization of follicle stimulating hormone and proadrenomedullin N-20 terminal peptide-like peptide in the same secretory granules of the gonadotropes

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    Expression of proadrenomedullin-derived peptides in the rat, cow and human pituitary was studied by a variety of techniques. Immunocytochemical detection showed a widespread expression of adrenomedullin peptide in the adenohypophysis and the neural lobe, with low expression in the intermediate pituitary. Proadrenomedullin N-20 terminal peptide (PAMP)-immunoreactivity was also present in the anterior pituitary but showed a more marked heterogeneous distribution, with cells going from very strong to negative immunostaining. Lower levels of PAMP were found in the neural lobe. Interestingly, the distribution of adrenomedullin and PAMP immunoreactivity in the anterior pituitary did not completely overlap. In the present study, we concentrated our efforts to determine which cell type of the adenohypophysis expresses PAMP. Paraffin and semithin serial sections immunostained for PAMP and the classical pituitary hormones revealed that a subpopulation of the gonadotropes expresses high levels of PAMP-immunoreactive material. Ultrastructural analysis clearly showed PAMP-immunoreactivity in the follicle stimulating hormone (FSH)-containing large secretory granules of the gonadotropes, suggesting simultaneous secretion of PAMP and FSH by this cell type. Three mouse adenohypophysis-derived cell lines (AtT20, GH3, and alphaT3-1 derived from corticotropes, lacto/somatotropes and gonadotropes, respectively) were also analysed and showed expression of both proadrenomedullin-derived peptides and their mRNA. Functional studies in these three cell lines showed that neither adrenomedullin nor PAMP was able to stimulate cAMP production in our experimental conditions. Taken together, our results support that proadrenomedullin derived peptides are expressed in the pituitary in cell-specific and not overlapping patterns, that could be explained by differences in postranslational processing. Our data showing costorage of PAMP and FSH in the same secretory granules open a way by which PAMP could be involved in the control of reproductive physiology in a coordinated manner with FSH
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