Byline: K. M. Lau (1), M. K. Kim (2), K. M. Kim (3) In this paper we present results of a numerical study using the NASA finite-volume GCM to elucidate a plausible mechanism for aerosol impact on the ...Asian summer monsoon involving interaction with physical processes over the Tibetan Plateau (TP). During the pre-monsoon season of March--April, dusts from the deserts of western China, Afghanistan/Pakistan, and the Middle East are transported into and stacked up against the northern and southern slopes of the TP. The absorption of solar radiation by dust heats up the elevated surface air over the slopes. On the southern slopes, the atmospheric heating is reinforced by black carbon from local emission. The heated air rises via dry convection, creating a positive temperature anomaly in the mid-to-upper troposphere over the TP relative to the region to the south. In May through early June in a manner akin to an "elevated heat pump", the rising hot air forced by the increasing heating in the upper troposphere, draws in warm and moist air over the Indian subcontinent, setting the stage for the onset of the South Asia summer monsoon. Our results suggest that increased dust loading coupled with black carbon emission from local sources in northern India during late spring may lead to an advance of the rainy periods and subsequently an intensification of the Indian summer monsoon. The enhanced rainfall over India is associated with the development of an aerosol-induced large-scale sea level pressure anomaly pattern, which causes the East Asia (Mei-yu) rain belt to shift northwestward, suppressing rainfall over East Asia and the adjacent oceanic regions. Author Affiliation: (1) Laboratory for Atmospheres, NASA Goddard Space Flight Center, Greenbelt, MD, USA (2) Department of Atmospheric Science, Kongju National University, Gongju, Korea (3) Science Systems and Applications, Inc, Lanham, MD, USA Article History: Registration Date: 12/01/2006 Received Date: 12/07/2005 Accepted Date: 15/12/2005 Online Date: 09/02/2006
Preliminary observational evidences are presented showing that the Indian subcontinent and surrounding regions are subject to heavy loading of absorbing aerosols, i.e., dust and black carbon, which ...possess spatial and temporal variability that are closely linked to those of the Asian monsoon water cycle. Consistent with the Elevated Heat Pump hypothesis, we find that increased loading of absorbing aerosols over the Indo‐Gangetic Plain in the pre‐monsoon season is associated with a) increased heating of the upper troposphere, with the formation of a warm‐core upper level anticyclone over the Tibetan Plateau in April–May, b) an advance of the monsoon rainy season in northern India in May, and c) subsequent increased rainfall over the Indian subcontinent, and decreased rainfall over East Asia in June–July.
In this study, the authors apply the NCEP–NCAR reanalysis and other observations to depict the association of the Asian–Pacific–American climate with the East Asian jet stream (EAJS). With an ...emphasis on boreal winter seasons and on interannual timescales, they analyze the variations of the EAJS and their relationships with El Niño–Southern Oscillation (ENSO) and extratropical North Pacific sea surface temperature (SST), and assess the relative connections of the EAJS and ENSO to the anomalies of atmospheric circulation, surface temperature, and precipitation in the Asian–Pacific–American region.
It is found that the EAJS is coupled to a teleconnection pattern spanning the entire Asian–Pacific–American region with the strongest signals over east Asia and the western Pacific. This pattern differs significantly from that associated with ENSO, which influences the earth’s climate extensively with a strongest impact on the climate over the central Pacific and east. A strong EAJS is associated with an intensification of the weather and climate systems in Asia and over the Pacific such as deepening of the east Asian trough and the Aleutian low and strengthening of the east Asian winter monsoon. It is linked to colder and drier conditions in east Asia and stronger convection over the tropical Asia–Australia sector. Compared with ENSO, the EAJS seems to link to the climate signals of Asia and the Pacific more strongly. An intensified EAJS is also associated with anomalies of temperature and precipitation in North America due to the related changes in stationary wave patterns.
While the EAJS does not strongly link to the tropical central-eastern Pacific SST, it is significantly associated with the extratropical North Pacific SST, more specifically the second most dominant mode of the empirical orthogonal function analysis of the SST. In addition, a strong (weak) EAJS seems to follow a large (small) meridional gradient of the western Pacific SST associated with warming (cooling) in the Tropics–subtropics and cooling (warming) in the extratropics.
Anatomy of STEM teaching in North American universities Stains, M; Harshman, J; Barker, M K ...
Science (American Association for the Advancement of Science),
2018-Mar-30, 2018-03-30, 20180330, Letnik:
359, Številka:
6383
Journal Article
Recenzirano
Odprti dostop
Lecture is prominent, but practices vary
A large body of evidence demonstrates that strategies that promote student interactions and cognitively engage students with content (
1
) lead to gains in ...learning and attitudinal outcomes for students in science, technology, engineering, and mathematics (STEM) courses (
1
,
2
). Many educational and governmental bodies have called for and supported adoption of these student-centered strategies throughout the undergraduate STEM curriculum. But to the extent that we have pictures of the STEM undergraduate instructional landscape, it has mostly been provided through self-report surveys of faculty members, within a particular STEM discipline e.g., (
3
–
6
). Such surveys are prone to reliability threats and can underestimate the complexity of classroom environments, and few are implemented nationally to provide valid and reliable data (
7
). Reflecting the limited state of these data, a report from the U.S. National Academies of Sciences, Engineering, and Medicine called for improved data collection to understand the use of evidence-based instructional practices (
8
). We report here a major step toward a characterization of STEM teaching practices in North American universities based on classroom observations from over 2000 classes taught by more than 500 STEM faculty members across 25 institutions.
Colorectal cancer (CRC) is the second most deadly cancer. Global incidence and mortality are likely to be increased in the coming decades. Although the deaths associated with CRC are very high in ...high-income countries, the incidence and fatalities related to CRC are growing in developing countries too. CRC detected early is entirely curable by surgery and subsequent medications. However, the recurrence rate is high, and cancer drug resistance increases the treatment failure rate. Access to early diagnosis and treatment of CRC for survival is somewhat possible in developed countries. However, these facilities are rarely available in developing countries. Highlighting the current status of CRC, its development, risk factors, and management is crucial in creating public awareness. Therefore, in this review, we have comprehensively discussed the current global epidemiology, drug resistance, challenges, risk factors, and preventive and treatment strategies of CRC. Additionally, there is a brief discussion on the CRC development pathways and recommendations for preventing and treating CRC.
In this study, we find from analyses of projections of 14 CMIP5 models a robust, canonical global response in rainfall characteristics to a warming climate. Under a scenario of 1% increase per year ...of CO2 emission, the model ensemble projects globally more heavy precipitation (+7 ± 2.4%K−1), less moderate precipitation (−2.5 ± 0.6%K−1), more light precipitation (+1.8 ± 1.3%K−1), and increased length of dry (no‐rain) periods (+4.7 ± 2.1%K−1). Regionally, a majority of the models project a consistent response with more heavy precipitation over climatologically wet regions of the deep tropics, especially the equatorial Pacific Ocean and the Asian monsoon regions, and more dry periods over the land areas of the subtropics and the tropical marginal convective zones. Our results suggest that increased CO2 emissions induce a global adjustment in circulation and moisture availability manifested in basic changes in global precipitation characteristics, including increasing risks of severe floods and droughts in preferred geographic locations worldwide.
Key Points
A canonical rainfall response is found in CMIP‐5 models
increased floods and droughts under global warming are connected
Changing rainfall types are more sensitive than total rainfall
For better exciton separation and high catalytic activity, the most trailblazing stratagem is to construct defect engineered low-dimensional p–n heterojunction framed photocatalytic systems. In this ...context, we have developed a rod–sheet (1D–2D) p–n heterojunction of MCeO2–BiFeO3 by a simple hydrothermal method and scrutinized its photocatalytic performance toward N2 fixation and phenol/Cr(VI) detoxification. The intimate contact between MCeO2 and BiFeO3 in the junction material is well established via X-ray diffraction (XRD), UV–vis diffuse reflectance spectrosopy (DRS), transmission electron microscopy (TEM), and photoelectrochemical studies. Further, scanning electron microscopy (SEM) and TEM pictures clearly support the decoration of MCeO2 nanorods over BiFeO3 sheets and also depict the junction boundary. Additionally, photoluminescence (PL), electron paramagnetic resonance (EPR), X-ray photoelectron spectroscopy (XPS), and Raman measurements give solid evidence toward the presence of an oxygen vacancy. Moreover, the Mott–Schottky result indicates a feasible band edge potential favoring the p–n heterojunction with a built-in electric field between BiFeO3 and MCeO2 favoring a double charge dynamic. The MCeO2–BFO p–n junction displays a notable catalytic activity, i.e., 98.2% Cr(VI) reduction and 85% phenol photo-oxidation, and produces 117.77 μmol h–1 g–1 of ammonia under light irradiation. Electrochemical analysis suggests a four-electron/five proton-coupled N2 photoreduction pathway. The designed oxygen vacancy oriented p–n heterojunction suffering double charge migration shows significant catalytic performance due to effective electron–hole separation as justified via PL, electrochemical impedance spectra (EIS), and Bode phase analysis.
In this paper, the authors present a description of the internal dynamics and boundary forcing characteristics of two major subcomponents of the Asian summer monsoon (ASM), that is, the South Asian ...monsoon (SAM) and the East–Southeast Asian monsoon (EAM). The description is based on a new monsoon-climate paradigm in which the variability of ASM is considered as the outcome of the interplay of a “fast” and an “intermediate” monsoon subsystem, under the influence of “slow” external forcings. Two sets of regional monsoon indices derived from dynamically consistent rainfall and wind data are used in this study. Results show that the internal dynamics of SAM are representative of a “classical” monsoon system in which the anomalous circulation is governed by Rossby wave dynamics, where anomalous vorticity induced by an off-equatorial heat source is balanced by the advection of planetary vorticity. On the other hand, the internal dynamics of EAM are characterized by a “hybrid” monsoon system featuring multicellular meridional circulation over the East Asian sector, extending from the deep Tropics to the midlatitudes. These meridional cells link tropical heating to extratropical circulation systems via the East Asian jet stream and are responsible for the observed zonally oriented anomalous rainfall patterns over East and Southeast Asia and the subtropical western Pacific. In the extratropical regions, the major upper-level vorticity balance is between the advection and generation by anomalous divergent circulation and basic-state circulation. A consequence of the different dynamical underpinnings is that EAM is associated with stronger extratropical teleconnection patterns to regions outside ASM compared to SAM.
The interannual variability of SAM is linked to basin-scale SST fluctuation with pronounced signals in the equatorial eastern Pacific. During the boreal spring, warming of the Arabian Sea and the subtropical western Pacific may lead to a strong SAM. For EAM, interannual variability is tied to SST anomalies over the East China Sea, the Sea of Japan (East Sea), and the South China Sea regions, while the linkage to equatorial basin-scale SST anomaly is weak at best. A strong EAM is foreshadowed by a large-scale SST anomaly dipole with warming (cooling) in the subtropical central (eastern) Pacific.
Comparison with the P. J. Webster and S. Yang (WY) monsoon index shows that WY is not significantly correlated with either the SAM or EAM regional-scale rainfall separately. It is demonstrated that WY can be considered as a measure of the large-scale atmospheric circulation state over the Indian/Pacific Ocean basin, including the integrated heat source over the ASM region. As such, the regional monsoon indices developed in this paper and WY provide a complementary description of the broadscale and regional aspects of the ASM.
Context:
Vitamin D deficiency during pregnancy may be associated with suboptimal fetal growth, but direct evidence is lacking.
Objectives:
The aim of the study was to validate a method for fetal ...femur volume (FV) measurement using three-dimensional ultrasound and to detect correlations between FV and maternal vitamin D concentration.
Design, Setting, and Participants:
A novel method for assessing FV consists of three ultrasound measurements—femur length, proximal metaphyseal diameter (PMD), and midshaft diameter—and a volume equation; this was validated by comparing ultrasound to computed tomography measurements in six pregnancies after mid-trimester termination. This method was then applied in a cohort of healthy pregnant women participating in the Southampton Women Survey. Fetal three-dimensional ultrasound and maternal 25-hydroxyvitamin D 25(OH)D levels were performed at 34 wk; dual-energy x-ray absorptiometry of the newborn was performed shortly after birth. Univariate and multiple linear regression analyses were performed between maternal characteristics and fetal outcomes.
Main Outcome Measures:
We performed ultrasound measurements of the fetal femur.
Results:
In 357 pregnant participants, serum 25(OH)D correlated significantly with FV (P = 0.006; r = 0.147) and PMD (P = 0.001; r = 0.176); FV also demonstrated positive univariate correlations with maternal height (P < 0.001; r = 0.246), weight (P = 0.003; r = 0.160), triceps skinfold thickness (P = 0.013; r = 0.134), and a borderline negative effect from smoking (P = 0.061). On multiple regression, independent predictors of FV were the maternal height and triceps skinfold thickness; the effect of 25(OH)D on FV was attenuated, but it remained significant for PMD.
Conclusion:
Using a novel method for assessing FV, independent predictors of femoral size were maternal height, adiposity, and serum vitamin D. Future trials should establish whether pregnancy supplementation with vitamin D is beneficial for the fetal skeleton, using FV and PMD as fetal outcome measures.
Summary
Background
Gastric cancer can be divided into cardia and noncardia gastric adenocarcinoma (NCGA). Non cardia gastric cancer is a disease that has declined in global incidence but has remained ...as an extremely lethal cancer.
Aim
To review recent advances in epidemiology and strategies in prevention of non cardia gastric cancer.
Methods
A rapid literature search strategy was developed for all English language literature published before March 2013. The search was conducted using the electronic databases PubMed and EMBASE. The search strategy included the keywords ‘stomach neoplasms’, ‘gastric cancer’, ‘epidemiology’, ‘risk factor’, ‘early detection of cancer’, ‘mass screening’, ‘cancer burden’, ‘prevention’ and ‘cost‐effectiveness’. The search strategy was adjusted according to different requirements for each database. The specific search was also performed in cancer‐related websites for country‐specific information. The search was limited to past 10 years.
Results
Gastric cancer is the fifth most common cancer but the third leading cause of cancer death. The case fatality rate is 75%. Screening by radiological or endoscopic methods has limited success in prevention of gastric cancer. Helicobacter pylori has been identified as a carcinogen, accounting for 60–70% of gastric cancer globally and eradication is a potential preventive measure. A meta‐analysis in 2009 demonstrated that individuals treated with H. pylori eradication therapy can reduce gastric cancer risk. The extended Shandong Intervention trial that lasted 14.3 years showed that H. pylori eradication therapy significantly reduced gastric cancer incidence by 39%. Consensus groups from Asia, Europe and Japan have recommended H. pylori eradication as primary prevention in high‐risk areas. Following eradication therapy, endoscopic surveillance of pre‐malignant lesions using enhanced imaging appears to be another promising preventive strategy.
Conclusions
Gastric cancer remains a major diagnostic and therapeutic challenge. There is emerging evidence that H. pylori eradication in high gastric cancer regions can lead to a decline in the incidence of this highly lethal disease.
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