8,357 research outputs found
Natural and Synthetic Corticosteroids Inhibit Uptake\u3csub\u3e2\u3c/sub\u3e-Mediated Transport in CNS Neurons
In addition to exerting actions via mineralocorticoid and glucocorticoid receptors, corticosteroids also act by inhibiting uptake2, a high-capacity monoamine transport system originally described in peripheral tissues. Recent studies have demonstrated that uptake2 transporters are expressed in the brain and play roles in monoamine clearance, suggesting that they mediate some corticosteroid effects on physiological and behavioral processes. However, the sensitivity of brain uptake2 to many natural and synthetic corticosteroids has not been characterized. Cultured rat cerebellar granule neurons (CGNs) were previously shown to exhibit corticosterone-sensitive accumulation of the uptake2 substrate1-methyl-4-phenylpyridinium (MPP+). We examined the expression of uptake1 and uptake2 transporters in CGNs, and tested the effects of a variety of natural and synthetic corticosteroids on accumulation of [3H]-MPP+ by these cells. Cultured rat CGNs expressed mRNA for three uptake2-like transporters: organic cation transporters 1 and 3, and the plasma membrane monoamine transporter. They did not express mRNA for the dopamine or norepinephrine transporters, and expressed very little mRNA for the serotonin reuptake transporter. Accumulation of [3H]-MPP+ by CGNs was dose-dependently inhibited by corticosterone and decynium-22, known inhibitors of uptake2. Accumulation of MPP+ was also dose-dependently inhibited, with varying efficacies, by aldosterone, 11-deoxycorticosterone, cortisol, and cortisone, and by the synthetic glucocorticoids betamethasone, dexamethasone and prednisolone, and the glucocorticoid receptor antagonist RU38486. These studies demonstrate that uptake2 in the CNS is inhibited by a variety of natural and synthetic corticosteroids, and suggest that inhibition of uptake2-mediated monoamine clearance may underlie some behavioral and physiological effects of these hormones
Sexual and reproductive health of adolescents in rural Nepal: Knowledge, attitudes and behavior
Background: Nepal has a relatively young and growing population, like most low-income countries. Recently, Nepal has accelerated its commitment to the International Conference on Population and Development (ICPD) Programme of Action by introducing a programme focusing on the sexual and reproductive health of adolescents. This paper aims to report the sexual health knowledge, attitudes and behaviour of adolescents in rural Nepal. Methods: A survey was conducted in four districts of Nepal with representative sample among adolescents aged 15ā19 years using pre-tested structured questionnaire in 2011. Questionnaire contents socio-demographic questions including knowledge, attitudes and behaviours related to reproductive and sexual health. The study was approved by the Nepal Health Research Council. Results: A total 3041 adolescents (mean age 16.4 years, 49.4% male and 50.6% female) completed the questionnaire. The data indicated that HIV/AIDS and other reproductive and sexual health knowledge among the respondents was moderate. Male respondents have better knowledge on HIV/AIDS compare to female respondents. Similarly, male have better access to modern means of communications. Both male and female were equally likely to say that they had used a condom the last time they had sex. A small proportion of all respondents (9.3%) had acquired emergency contraception, two thirds of those were male (65%) and among total users of emergency contraceptives, 85% were unmarried. Conclusions: Both education and youth-friendly services, targeting to female adolescents are required to improve the sexual health status of adolescents. The findings have important implications for the (re-)development sexual health interventions for adolescents in Nepal
Soil media CO\u3csub\u3e2\u3c/sub\u3e and N\u3csub\u3e2\u3c/sub\u3eO fluxes dynamics from sand-based roadside bioretention systems
Green stormwater infrastructure such as bioretention is commonly implemented in urban areas for stormwater quality improvements. Although bioretention systems\u27 soil media and vegetation have the potential to increase carbon (C) and nitrogen (N) storage for climate change mitigation, this storage potential has not been rigorously studied, and any analysis of it must consider the question of whether bioretention emits greenhouse gases to the atmosphere. We monitored eight roadside bioretention cells for CO2-C and N2O-N fluxes during two growing seasons (May through October) in Vermont, USA. C and N stocks in the soil media layers, microbes, and aboveground vegetation were also quantified to determine the overall C and N balance. Our bioretention cells contained three different treatments: plant species mix (high diversity versus low diversity), soil media (presence or absence of P-sorbent filter layer), and hydrologic (enhanced rainfall and runoff in some cells). CO2-C and N2O-N fluxes from all cells averaged 194 mg m-2 h-1 (range: 37 to 374 mg m-2 h-1) and 10 Ī¼g m-2 h-1 (range: -1100 to 330 Ī¼g m-2 h-1), respectively. There were no treatment-induced changes on gas fluxes. CO2-C fluxes were highly significantly correlated with soil temperature (R2 = 0.68, p \u3c 0.0001), while N2O-N fluxes were weakly correlated with temperature (R2 = 0.017, p = 0.04). Bioretention soil media contained the largest pool of total C and N (17122 g and 1236 g, respectively) when compared with vegetation and microbial pools. Microbial biomass C made up 14% (1936 g) of the total soil C in the upper 30 cm media layer. The total C and N sequestered by bioretention plants were 13,020 g and 320 g, respectively. After accounting for C and N losses via gas fluxes, the bioretention appeared to be a net sink for those nutrients. We also compared our bioretention gas fluxes to those from a variety of natural (i.e., grasslands and forests) and artificial (i.e., fertilized and irrigated or engineered) land-use types. We found bioretention fluxes to be in the mid-range among these land-use types, mostly likely due to organic matter (OM) influences on decomposition being similar to processes in natural systems
Multichannel parametrization of \pi N scattering amplitudes and extraction of resonance parameters
We present results of a new multichannel partial-wave analysis for \pi N
scattering in the c.m. energy range 1080 to 2100 MeV. This work explicitly
includes \eta N and K \Lambda channels and the single pion photoproduction
channel. Resonance parameters were extracted by fitting partial-wave amplitudes
from all considered channels using a multichannel parametrization that is
consistent with S-matrix unitarity. The resonance parameters so obtained are
compared to predictions of quark models
Solving hidden terminal problem in MU-MIMO WLANs with fairness and throughput-aware precoding and a degrees-of-freedom-based MAC design
Ā© 2016, Shrestha et al. We generally emphasize that the zeroforcing (ZF) technique backed by an appropriate medium access control (MAC) protocol can be used to address the inevitable hidden terminal (HT) problem in multi-user multiple input multiple output (MU-MIMO) wireless local area network (WLAN) settings. However, to address the implementation-specific requirements of MU-MIMO WLANs, such as fairness in client access and throughput of the network, we propose a fairness and a throughput-aware ZF precoding in our design at the physical layer (PHY). This precoding scheme not only solves the HT problem but also meets the fairness and the throughput requirements of MU-MIMO WLANs. Besides, we design a MAC layer protocol, supportive to PHY, which decides transmission opportunities (TXOPs) among access points (APs) based on the available degrees of freedom (DoF). We make a mandatory provision in our design that APs should have a sufficient DoF. This can ensure collision-free transmission whenever APs/transmitters transmit in the HT scenario. Additionally, we design an improved channel sounding process for MU-MIMO WLANs with a less signaling overhead than IEEE802.11ac. We demonstrate the feasibility of our PHY in a USRP2/GNU Radio testbed prototype in the lab settings. It is found that our PHY improves the SNR and effective SNR of the received signal from about 5 to 11 dB in the HT scenario. The performance of our MAC design is checked with simulation studies in a typical six-antenna AP and clients scenario. We observe that our MAC protocol has a slightly higher signaling overhead than traditional ready to send/clear to send (RTS/CTS) due to design constraints; however, the signaling time overheads are reduced by 98.67 Ī¼s compared to IEEE802.11ac. Another interesting aspect to highlight is the constant Throughput gain of four to five times that of the traditional RTS/CTS. Our MAC protocol obtains this gain as early as 98.67 Ī¼s compared to IEEE802.11ac
Zeroforcing precoding based MAC design to address hidden terminals in MU-MIMO WLANs
Ā© 2015 IEEE. This paper focuses on the Medium Access Control (MAC) layer design for an inevitable Hidden Terminal problem in Multi User Multiple Input Multiple Output (MU-MIMO) Wireless Local Area Networks (WLANs). Specifically, our MAC design is supported by the precoding vectors obtained by Zeroforcing technique which are used to address the Hidden Terminals. An efficient channel sounding process is used by our MAC protocol to obtain the Channel State Information (CSI) from the desired and undesired clients which are used to calculate the precoding vectors at the transmitters (Access Points). Our MAC design then uses these precoding vectors in order to null interferences among the undesired clients to avoid collision of signals and to maintain the concurrent transmissions among the desired clients. The the parameters such as network capacity, signaling overheads and fairness are considered in the design. Our MAC layer design shows a slightly higher signaling overhead compared to RTS/CTS scheme. However, due to the concurrent transmissions after the handshaking process, the cost of singling overheads are compensated. The simulation study of our MAC layer design shows a remarkable constant network capacity gain of 4-5 times in comparison to traditional RTS/CTS. Moreover, the gain is irrespective to the available air-time
Use of continuous simulation model (COSIMAT) as a complementary tool to model sewer systems: a case study on the Paruck collector, Brussels, Belgium
Episodic Combined Sewer Overflow (CSO) discharges effectively control the ecological status of receiving water bodies. Hydrodynamic models like the Storm Water Management Model (SWMM) are often used to model the CSO events. However, such detailed models are computationally demanding especially when a longāterm simulation of a complex system is required. Considering this, we developed an alternative simple continuous simulation model (COSIMAT) using the SIMULINKā¢ module in MATLABā¢ as a means of solving the issue of computational time associated with the detailed models. The COSIMAT model was tested against a detailed model set up on the SWMM. The Paruck collector ā one of the major Collector of the Brusselsā sewer system was used as an example case. Results showed that the accuracy of the simplified COSIMAT model was comparable to that of the detailed hydrodynamic model (SWMM) with a significant reduction of computational time by a factor of 8. We believe such alternative approaches would be useful to replace a computationally demanding model component of an integrated modelling system of a complex sewer system
Effects of different soil media, vegetation, and hydrologic treatments on nutrient and sediment removal in roadside bioretention systems
Water quality performance of eight roadside bioretention cells in their third and fourth years of implementation were evaluated in Burlington, Vermont. Bioretention cells received varying treatments: (1) vegetation with high-diversity (7 species) and low-diversity plant mix (2 species); (2) proprietary SorbtiveMediaā¢ (SM) containing iron and aluminum oxide granules to enhance sorption capacity for phosphorus; and (3) enhanced rainfall and runoff (RR) to certain cells (including one with SM treatment) at three levels (15%, 20%, 60% more than their control counterparts), mimicking anticipated precipitation increases associated with climate change. A total of 121 storms across all cells were evaluated in 2015 and 2016 for total suspended solids (TSS), nitrate/nitrite-nitrogen (NOx), ortho-phosphorus (Ortho-P), total nitrogen (TN) and total phosphorus (TP). Heavy metals were also measured for a few storms, but in 2014 and 2015 only. Simultaneous measurements of flow rates and volumes allowed for evaluation of the cellsā hydraulic performances and estimation of pollutant load removal efficiencies and EMC reductions. Significant average reductions in effluent stormwater volumes (75%; range: 48ā96%) and peak flows (91%; range: 86ā96%) was reported, with 31% of the storms events (all less than 25.4 mm (1 in.), and one 39.4 mm (1.55 in.)) depth completely captured by bioretention cells. Influent TSS concentrations and event mean concentrations (EMCs) was mostly significantly reduced, and TSS loads were well retained by all bioretention cells (94%; range: 89ā99%) irrespective of treatments, storm characteristics or seasonality. In contrast, nutrient removal was treatment-dependent, where the SM treatments consistently removed P concentrations, loads and EMCs, and sometimes N as well. The vegetation and RR treatments mostly exported nutrients to the effluent for those three metrics with varying significance. We attribute observed nutrient exports to the presence of excess compost in the soil media. Rainfall depth and peak inflow rate had consistently negative effects on all nutrient removal efficiencies from the bioretention cells likely by increasing pollutant mobilization. Seasonality followed by soil media presence, and antecedent dry period were other predictors significantly influencing removal efficiencies for some nutrient types. Results from the analysis will be useful to make bioretention designers aware of the hydrologic and other design factors that will be the most critical to the performance of the bioretention systems in response to interactive effects of climate change
Understanding parents and professionals knowledge and awareness of autism in Nepal
Autism is a global phenomenon. Yet, there is a dearth of knowledge of how it is understood and its impact in low-income countries. We examined parentsā and professionalsā understanding of autism in one low-income country, Nepal. We conducted focus groups and semi-structured interviews with parents of autistic and non-autistic children and education and health professionals from urban and rural settings (nā=ā106), asking questions about typical and atypical development and presenting vignettes of children to prompt discussion. Overall, parents of typically developing children and professionals had little explicit awareness of autism. They did, however, use some distinctive terms to describe children with autism from children with other developmental conditions. Furthermore, most participants felt that environmental factors, including in-utero stressors and birth complications, parenting style and home or school environment were key causes of atypical child development and further called for greater efforts to raise awareness and build community capacity to address autism. This is the first study to show the striking lack of awareness of autism by parents and professionals alike. These results have important implications for future work in Nepal aiming both to estimate the prevalence of autism and to enhance support available for autistic children and their families
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