1,762 research outputs found
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Characteristics of Bay of Bengal monsoon depressions in the 21st Century
We show that 21st century increase in radiative forcing does not significantly impact the frequency of South Asian summer monsoon depressions (MDs) or their trajectories in the Coupled Model Intercomparison Project Phase 5 general circulation models (GCMs). A significant relationship exists between the climatological occurrences of MDs and the strength of the background upper (lower) tropospheric meridional (zonal) winds and tropospheric moisture in the core genesis region of MDs. Likewise, there is a strong relationship between the strength of the meridional tropospheric temperature gradient in the GCMs and the trajectories of MDs over land. While monsoon dynamics progressively weakens in the future, atmospheric moisture exhibits a strong increase, limiting the impact of changes in dynamics on the frequency of MDs. Moreover, the weakening of meridional tropospheric temperature gradient in the future is substantially weaker than its inherent underestimation in the GCMs. Our results also indicate that future increases in the extreme wet events are dominated by nondepression day occurrences, which may render the monsoon extremes less predictable in the future
Scenario of Accelerating Universe from the Phenomenological \Lambda- Models
Dark matter, the major component of the matter content of the Universe,
played a significant role at early stages during structure formation. But at
present the Universe is dark energy dominated as well as accelerating. Here,
the presence of dark energy has been established by including a time-dependent
term in the Einstein's field equations. This model is compatible with
the idea of an accelerating Universe so far as the value of the deceleration
parameter is concerned. Possibility of a change in sign of the deceleration
parameter is also discussed. The impact of considering the speed of light as
variable in the field equations has also been investigated by using a well
known time-dependent model.Comment: Latex, 9 pages, Major change
Curcumin and derivatives function through protein phosphatase 2A and presenilin orthologues in Dictyostelium discoideum.
Natural compounds often have complex molecular structures and unknown molecular targets. These characteristics make them difficult to analyse using a classical pharmacological approach. Curcumin, the main curcuminoid of turmeric, is a complex molecule possessing wide-ranging biological activities, cellular mechanisms and roles in potential therapeutic treatment including Alzheimer's disease and cancer. Here, we investigate the physiological effects and molecular targets of curcumin in Dictyostelium discoideum We show curcumin causes acute effects on cell behaviour, reduces cell growth, and slows multicellular development. We then employ a range of structurally related compounds to show the distinct role of different structural groups cell behaviour, growth, and development, highlighting active moieties in cell function, and showing that these cellular effects are unrelated to the well-known antioxidant activity of curcumin. Molecular mechanisms underlying the effect of curcumin and one synthetic analogue (EF24) were then investigated to identify a curcumin-resistant mutant lacking the protein phosphatase 2A regulatory subunit (PsrA) and an EF24-resistant mutant lacking the presenilin 1 orthologue (PsenB). Using in-silico docking analysis, we then show that curcumin may function through direct binding to a key regulatory region of PsrA. These findings reveal novel cellular and molecular mechanisms for the function of curcumin and related compounds
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SILICON CARBIDE MICRO-DEVICES FOR COMBUSTION GAS SENSING UNDER HARSH CONDITIONS
A sensor based on the wide bandgap semiconductor, silicon carbide (SiC), has been developed for the detection of combustion products in power plant environments. The sensor is a catalytic gate field effect device that can detect hydrogen containing species in chemically reactive, high temperature environments. For these capacitive sensors we have determined that the optimum sensor operating point in terms of sensor lifetime and response time is at midgap. Detailed measurements of the oxide leakage current as a function of temperature were performed to investigate the high temperature reliability of the devices. In addition, robust metallization and electrical contacting techniques have been developed for device operation at elevated temperatures. To characterize the time response of the sensor responses in the millisecond range, a conceptually new apparatus has been built. Using laser induced fluorescence imaging techniques we have shown that the gas underneath the sensor can be completely exchanged with a time constant under 1 millisecond. Ultrahigh vacuum studies of the surface chemistry of the platinum gate have shown that sensor deactivation by adsorbed sulfur is a possible problem. Investigations on the chemical removal of sulfur by catalytic oxidation or reduction are continuing
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Fiber Optical Micro-detectors for Oxygen Sensing in Power Plants
Spectroscopy of Mo{sub 6}Cl{sub 12} immobilized in a sol-gel matrix and heated to 200 C has been performed. Oxygen quenching of the luminescence was observed. Aging Mo{sub 6}Cl{sub 12} to temperatures above 250 C converts the canary yellow Mo{sub 6}Cl{sub 12} to a non-luminescent gray solid. Preliminary experiments point to oxidation of the clusters as the likely cause of thermally induced changes in the physical and optical properties of the clusters
Knowledge, attitudes and practices related to dietary salt intake among adults in North India.
OBJECTIVE: To assess the knowledge, attitudes and practices related to salt consumption among adults in rural and urban North India. DESIGN: Data for the study were obtained from a community-based cross-sectional survey using an interviewer-administered questionnaire and 24 h urine samples. SETTING: Data collection was conducted during March-October 2012 in rural Haryana and urban Delhi in North India. PARTICIPANTS: Adults (n 1635) aged ≥20 years (701 in rural Haryana; 934 in urban Delhi). RESULTS: Twenty-four per cent of rural and 40·5 % of urban participants knew that a high-salt diet causes high blood pressure. Nearly one-fifth of both rural and urban participants knew that there should be a maximum daily limit for consumption of salt. In rural and urban areas, 46·6 and 45·1 %, respectively, perceived it important to reduce the salt content of their diet; however, only 3·7 and 10·2 %, respectively, reported taking some actions. Participants reported they were consuming 'too little salt', 'just the right amount of salt' or 'too much salt', but their corresponding mean (95 % CI) actual salt consumption (g/d; as measured by 24 h urinary Na excretion) was higher, especially among rural participants (rural: 9·2 (8·13, 10·22), 8·5 (8·19, 8·77) or 8·4 (7·72, 8·99); urban: 5·6 (4·67, 6·57), 5·7 (5·32, 6·01) or 4·6 (4·10, 5·14), respectively). CONCLUSIONS: Knowledge about the deleterious health impact of excess salt consumption is low in this population. Tailored public education for salt reduction is warranted with a particular focus on rural residents
Prevalence and incidence of hypertension: Results from a representative cohort of over 16,000 adults in three cities of south Asia
Background: Despite high projected burden, hypertension incidence data are lacking in South Asian population. We measured hypertension prevalence and incidence in the Center for cArdio-metabolic Risk Reduction in South Asia (CARRS) adult cohort.Methods: The CARRS Study recruited representative samples of Chennai, Delhi, and Karachi in 2010/11, and socio-demographic and risk factor data were obtained using a standard common protocol. Blood pressure (BP) was measured in the sitting position using electronic sphygmomanometer both at baseline and two year follow-up. Hypertension and control were defined by JNC 7 criteria.Results: In total, 16,287 participants were recruited (response rate=94.3%) and two year follow-up was completed in 12,504 (follow-up rate=79.2%). Hypertension was present in 30.1% men (95% CI: 28.7-31.5) and 26.8% women (25.7-27.9) at baseline. BP was controlled in 1 in 7 subjects with hypertension. At two years, among non-hypertensive adults, average systolic BP increased 2.6mm Hg (95% CI: 2.1-3.1), diastolic BP 0.7mm Hg (95% CI: 0.4-1.0), and 1 in 6 developed hypertension (82.6 per 1000 person years, 95% CI: 80.8-84.4). Risk for developing hypertension was associated with age, low socio-economic status, current alcohol use, overweight, pre-hypertension, and dysglycemia. Risk of incident hypertension was highest (RR=2.95, 95% CI: 2.53-3.45) in individuals with pre-hypertension compared to normal BP. Collectively, 4 modifiable risk factors (pre-hypertension, overweight, dysglycemia, and alcohol use) accounted for 78% of the population attributable risk of incident hypertension.Conclusion: High prevalence and poor control of hypertension, along with high incidence, in South Asian adult population call for urgent preventive measures
Curcumin suppresses the production of interleukin-6 in Prevotella intermedia lipopolysaccharide-activated RAW 264.7 cells
Curcumin suppresses the production of interleukin-6 in Prevotella intermedia lipopolysaccharide-activated RAW 264.7 cells
In First Person Shooter (FPS) games the Round Trip Time (RTT), i.e., the sum of the network delay from client to server and the network delay from server to client, impacts the gamer's performance considerably. Game client software usually has a built-in process to measure this RTT (also referred to as ping time), and therefore gamers do not want to connect to servers with a long ping time. This paper develops a methodology to evaluate the ping time in a scenario where gamers access a common gaming server over an access network, consisting of a link per user that connects this user to a shared aggregation node that in turn is connected to the gaming server via a bottleneck link. First, a model for the traffic the users and the server generate, is proposed based on experimental results of previous papers. It turns out that the characteristics of the (downstream) traffic from server to clients differ substantially from the characteristics of the client-to-server (upstream) traffic. Then, two queuing models are developed (one for the upstream and one for the downstream direction) and combined such that a quantile of the RTT can be calculated given all traffic and network parameters (packet sizes, packet inter-arrival times, link rate, network load, ). This methodology is subsequently used to assess the (quantile of the) RTT in a typical Digital Subscriber Line (DSL) access scenario. In particular, given the capacity dedicated to gaming traffic on the bottleneck link (between the aggregation node and gaming server), the number of gamers (or equivalently the gaming load the bottleneck link can support) is determined under the restriction that the quantile of the RTT should not exceed a predefined bound. It turns out that this tolerable load is surprisingly low in most circumstances. Finally, it is remarked that this conclusion depends to some extent on the details of the downstream traffic characteristics and that measurements reported in literature do not give conclusive evidence on the exact value of all parameters, such that, although the qualitative conclusion still remains valid, additional experiments could refine the detailed quantitative results
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