258 research outputs found
Absorption Cross Sections of NH_3, NH_2D, NHD_2, and ND_3 in the Spectral Range 140-220 nm and Implications for Planetary Isotopic Fractionation
Cross sections for photoabsorption of NH_3, NH_2D, NHD_2, and ND_3 in the spectral region 140-220 nm were determined at ~298 K using synchrotron radiation. Absorption spectra of NH_2D and NHD_2 were deduced from spectra of mixtures of NH_3 and ND_3, of which the equilibrium concentrations for all four isotopologues obey statistical distributions. Cross sections of NH_2D, NHD_2, and ND_3 are new. Oscillator strengths, an integration of absorption cross sections over the spectral lines, for both A â X and B â X systems of NH_3 agree satisfactorily with previous reports; values for NH_2D, NHD_2, and ND_3 agree with quantum chemical predictions. The photolysis of NH_3 provides a major source of reactive hydrogen in the lower stratosphere and upper troposphere of giant planets such as Jupiter. Incorporating the measured photoabsorption cross sections of NH_3 and NH_2D into the Caltech/JPL photochemical diffusive model for the atmosphere of Jupiter, we find that the photolysis efficiency of NH_2D is lower than that of NH_3 by as much as 30%. The D/H ratio in NH_2D/NH_3 for tracing the microphysics in the troposphere of Jupiter is also discussed
Women and Industry in Taiwan
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68847/2/10.1177_009770047900500303.pd
Isotopic Fractionation of Nitrogen in Ammonia in the Troposphere of Jupiter
Laboratory measurements of the photoabsorption cross section of ^(15)NH_3 at wavelengths between 140 and 220 nm are presented for the first time. Incorporating the measured photoabsorption cross sections of ^(15)NH_3 and ^(14)NH_3 into a one-dimensional photochemical diffusive model, we find that at 400 mbar, the photolytic efficiency of ^(15)NH_3 is about 38% greater than that of ^(14)NH_3. In addition, it is known that ammonia can condense in the region between 200 and 700 mbar, and the condensation tends to deplete the abundance ratio of ^(15)NH_3 and ^(14)NH_3. By matching the observed ratio of ^(15)NH_3 and ^(14)NH_3 at 400 mbar, the combined effect of photolysis and microphysics produces the ratio of (2.42 ± 0.34) à 10^(-3) in the deep atmosphere, in excellent agreement with the Galileo spacecraft measurements. The usefulness of the isotopic composition of ammonia as a tracer of chemical and dynamical processes in the troposphere of Jupiter is discussed
Vacuum ultraviolet photoabsorption spectra of nitrile ices for their identification on Pluto
Icy bodies, such as Pluto, are known to harbor simple and complex molecules. The recent New Horizons flyby of Pluto has revealed a complex surface composed of bright and dark ice surfaces, indicating a rich chemistry based on nitrogen (N2), methane (CH4), and carbon monoxide (CO). Nitrile (CN) containing molecules such as acetonitrile (CH3CN), propionitrile (CH3CH2CN), butyronitrile (CH3CH2CH2CN), and isobutyronitrile ((CH3)2CHCN) are some of the nitrile molecules that are known to be synthesized by radiative processing of such simple ices. Through the provision of a spectral atlas for such compounds we propose that such nitriles may be identified from the ALICE payload on board New Horizons</i
An econometric analysis of SARS and Avian flu on international tourist arrivals to Asia
This paper compares the impacts of SARS and human deaths arising from Avian Flu on international tourist arrivals to Asia. The effects of SARS and human deaths from Avian Flu will be compared directly according to human deaths. The nature of the short run and long run relationship is examined empirically by estimating a static line fixed effect model and a difference transformation dynamic model, respectively. Empirical results from the static fixed effect and difference transformation dynamic models are consistent, and indicate that both the short run and long run SARS effect have a more significant impact on international tourist arrivals than does Avian Flu. In addition, the effects of deaths arising from both SARS and Avian Flu suggest that SARS is more important to international tourist arrivals than is Avian Flu. Thus, while Avian Flu is here to stay, its effect is currently not as significant as that of SARS
Rapid intensification of Typhoon Hato (2017) over shallow water
© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Pun, I., Chan, J. C. L., Lin, I., Chan, K. T. E., Price, J. F., Ko, D. S., Lien, C., Wu, Y., & Huang, H. Rapid intensification of Typhoon Hato (2017) over shallow water. Sustainability, 11(13), (2019): 3709, doi:10.3390/su11133709.On 23 August, 2017, Typhoon Hato rapidly intensified by 10 kt within 3 h just prior to landfall in the city of Macau along the South China coast. Hatoâs surface winds in excess of 50 m sâ1 devastated the city, causing unprecedented damage and social impact. This study reveals that anomalously warm ocean conditions in the nearshore shallow water (depth < 30 m) likely played a key role in Hatoâs fast intensification. In particular, cooling of the sea surface temperature (SST) generated by Hato at the critical landfall point was estimated to be only 0.1â0.5 °C. The results from both a simple ocean mixing scheme and full dynamical ocean model indicate that SST cooling was minimized in the shallow coastal waters due to a lack of cool water at depth. Given the nearly invariant SST in the coastal waters, we estimate a large amount of heat flux, i.e., 1.9k W mâ2, during the landfall period. Experiments indicate that in the absence of shallow bathymetry, and thus, if nominal cool water had been available for vertical mixing, the SST cooling would have been enhanced from 0.1 °C to 1.4 °C, and sea to air heat flux reduced by about a quarter. Numerical simulations with an atmospheric model suggest that the intensity of Hato was very sensitive to air-sea heat flux in the coastal region, indicating the critical importance of coastal ocean hydrography.The work of I.-F.P. is supported by Taiwanâs Ministry of Science and Technology Grant MOST 107-2111-M-008-001-MY3. The work of J.C.L.C. is supported by the Research Grants Council of Hong Kong Grant E-CityU101/16. The work of I.-I.L. is supported by Taiwanâs Ministry of Science and Technology (MOST 106-2111-M-002-011-MY3, MOST 108-2111-M-002-014-MY2). The work of K.T.F.C. is jointly supported by the National Natural Science Foundation of China (41775097), and the National Natural Science Foundation of China and Macau Science and Technology Development Joint Fund (NSFC-FDCT), China and Macau (41861164027)
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Hypokalemia, Its Contributing Factors and Renal Outcomes in Patients with Chronic Kidney Disease
Background: In the chronic kidney disease (CKD) population, the impact of serum potassium (sK) on renal outcomes has been controversial. Moreover, the reasons for the potential prognostic value of hypokalemia have not been elucidated. Design, Participants & Measurements 2500 participants with CKD stage 1â4 in the Integrated CKD care program Kaohsiung for delaying Dialysis (ICKD) prospective observational study were analyzed and followed up for 2.7 years. Generalized additive model was fitted to determine the cutpoints and the U-shape association between sK and end-stage renal disease (ESRD). sK was classified into five groups with the cutpoints of 3.5, 4, 4.5 and 5 mEq/L. Cox proportional hazard regression models predicting the outcomes were used. Results: The mean age was 62.4 years, mean sK level was 4.2±0.5 mEq/L and average eGFR was 40.6 ml/min per 1.73 m2. Female vs male, diuretic use vs. non-use, hypertension, higher eGFR, bicarbonate, CRP and hemoglobin levels significantly correlated with hypokalemia. In patients with lower sK, nephrotic range proteinuria, and hypoalbuminemia were more prevalent but the use of RAS (renin-angiotensin system) inhibitors was less frequent. Hypokalemia was significantly associated with ESRD with hazard ratios (HRs) of 1.82 (95% CI, 1.03â3.22) in sK 5 mEq/L conferred 1.6-fold (95% CI,1.09â2.34) increased risk of ESRD compared with sK = 4.5â5 mEq/L. Hypokalemia was also associated with rapid decline of renal function defined as eGFR slope below 20% of the distribution range. Conclusion: In conclusion, both hypokalemia and hyperkalemia are associated with increased risk of ESRD in CKD population. Hypokalemia is related to increased use of diuretics, decreased use of RAS blockade and malnutrition, all of which may impose additive deleterious effects on renal outcomes
Extinction-free Census of AGNs in the AKARI/IRC North Ecliptic Pole Field from 23-band Infrared Photometry from Space Telescopes
In order to understand the interaction between the central black hole and the whole galaxy or their co-evolution history along with cosmic time, a complete census of active galactic nuclei (AGN) is crucial. However, AGNs are often missed in optical, UV and soft X-ray observations since they could be obscured by gas and dust. A mid-infrared (mid-IR) survey supported by multiwavelength data is one of the best ways to find obscured AGN activities because it suffers less from extinction. Previous large IR photometric surveys, e.g., WISE and Spitzer, have gaps between the mid-IR filters. Therefore, star forming galaxy (SFG)-AGN diagnostics in the mid-IR were limited. The AKARI satellite has a unique continuous 9-band filter coverage in the near to mid-IR wavelengths. In this work, we take advantage of the state-of-the-art spectral energy distribution (SED) modelling software, CIGALE, to find AGNs in mid-IR. We found 126 AGNs in the NEP-Wide field with this method. We also investigate the energy released from the AGN as a fraction of the total IR luminosity of a galaxy. We found that the AGN contribution is larger at higher redshifts for a given IR luminosity. With the upcoming deep IR surveys, e.g., JWST, we expect to find more AGNs with our method
Using spatial analysis to demonstrate the heterogeneity of the cardiovascular drug-prescribing pattern in Taiwan
<p>Abstract</p> <p>Background</p> <p>Geographic Information Systems (GIS) combined with spatial analytical methods could be helpful in examining patterns of drug use. Little attention has been paid to geographic variation of cardiovascular prescription use in Taiwan. The main objective was to use local spatial association statistics to test whether or not the cardiovascular medication-prescribing pattern is homogenous across 352 townships in Taiwan.</p> <p>Methods</p> <p>The statistical methods used were the global measures of Moran's <it>I </it>and Local Indicators of Spatial Association (LISA). While Moran's <it>I </it>provides information on the overall spatial distribution of the data, LISA provides information on types of spatial association at the local level. LISA statistics can also be used to identify influential locations in spatial association analysis. The major classes of prescription cardiovascular drugs were taken from Taiwan's National Health Insurance Research Database (NHIRD), which has a coverage rate of over 97%. The dosage of each prescription was converted into defined daily doses to measure the consumption of each class of drugs. Data were analyzed with ArcGIS and GeoDa at the township level.</p> <p>Results</p> <p>The LISA statistics showed an unusual use of cardiovascular medications in the southern townships with high local variation. Patterns of drug use also showed more low-low spatial clusters (cold spots) than high-high spatial clusters (hot spots), and those low-low associations were clustered in the rural areas.</p> <p>Conclusions</p> <p>The cardiovascular drug prescribing patterns were heterogeneous across Taiwan. In particular, a clear pattern of north-south disparity exists. Such spatial clustering helps prioritize the target areas that require better education concerning drug use.</p
The experience of admission to psychiatric hospital among Chinese adult patients in Hong Kong
<p>Abstract</p> <p>Background</p> <p>The paper reports on a study to evaluate the psychometric properties and cultural appropriateness of the Chinese translation of the Admission Experience Survey (AES).</p> <p>Methods</p> <p>The AES was translated into Chinese and back-translated. Content validity was established by focus groups and expert panel review. The Chinese version of the Admission Experience Survey (C-AES) was administered to 135 consecutively recruited adult psychiatric patients in the Castle Peak Hospital (Hong Kong SAR, China) within 48 hours of admission. Construct validity was assessed by comparing the scores from patients admitted voluntarily versus patients committed involuntarily, and those received physical or chemical restraint versus those who did not. The relationship between admission experience and psychopathology was examined by correlating C-AES scores with the Brief Psychiatric Rating Scale (BPRS) scores.</p> <p>Results</p> <p>Spearman's item-to-total correlations of the C-AES ranged from 0.50 to 0.74. Three factors from the C-AES were extracted using factor analysis. Item 12 was omitted because of poor internal consistency and factor loading. The factor structure of the Process Exclusion Scale (C-PES) corresponded to the English version, while some discrepancies were noted in the Perceived Coercion Scale (C-PCS) and the Negative Pressure Scale (C-NPS). All subscales had good internal consistencies. Scores were significantly higher for patients either committed involuntarily or subjected to chemical or physical restrain, independent on severity of psychotic symptoms.</p> <p>Conclusion</p> <p>The Chinese AES is a psychometrically sound instrument assessing the three different aspects of the experience of admission, namely "negative pressure, "process exclusion" and "perceived coercion". The potential of C-AES in exploring subjective experience of psychiatric admission and effects on treatment adherence should be further explored.</p
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