643 research outputs found
Oil bearing seasonal crops in India:energy and phytoremediation potential
Purpose: A variety of biomass plantations are being raised for energy production. This case study is on energy production potential of seasonal oil bearing crops in India. These crops have the advantage of producing oil (liquid fuel) as well as biomass as agro residue (solid fuel). The purpose of the study is to estimate total energy yields of oil bearing crops and compare with other types of energy plantations. Also oil bearing crops bioaccumulate metals and thus phytoremediate soil. This provides scope for waste water irrigation. Design/methodology/approach: Relevant published papers on energy production by raising oil bearing crops have been analyzed. The effect of waste water irrigation and agronomic practices on increasing productivity is given special attention. Findings: It is shown that the seasonal oil bearing crops such as castor have a high potential to generate energy and this is comparable to energy produced by many perennial grasses. The energy yields of castor under irrigated condition was 196Ă103 MJ/ha and this is comparable to the reed canary grass which yields 195Ă103 MJ/ha. Some of the oil bearing crops are also super accumulators of certain toxic metals. Research limitations/implications: In this study, only all the accessible papers on the topic could be analyzed. Practical implications: This case study indicates that raising oil bearing crops such as castor using waste water has many advantages which include high energy yields, utilization of waste water for productive purpose and phytoremediation of soil. Originality/value: The comparison made between various types of energy crops for their energy generation is an original contribution. Findings of economic and environmental benefits by waste water irrigation are also of value
Mass-Transport Models with Multiple-Chipping Processes
We study mass-transport models with multiple-chipping processes. The rates of
these processes are dependent on the chip size and mass of the fragmenting
site. In this context, we consider k-chip moves (where k = 1, 2, 3, ....); and
combinations of 1-chip, 2-chip and 3-chip moves. The corresponding mean-field
(MF) equations are solved to obtain the steady-state probability distributions,
P (m) vs. m. We also undertake Monte Carlo (MC) simulations of these models.
The MC results are in excellent agreement with the corresponding MF results,
demonstrating that MF theory is exact for these models.Comment: 18 pages, 4 figures, To appear in European Physical Journal
Remarks on 't Hooft's Brick Wall Model
A semi-classical reasoning leads to the non-commutativity of the space and
time coordinates near the horizon of Schwarzschild black hole. This
non-commutativity in turn provides a mechanism to interpret the brick wall
thickness hypothesis in 't Hooft's brick wall model as well as the boundary
condition imposed for the field considered. For concreteness, we consider a
noncommutative scalar field model near the horizon and derive the effective
metric via the equation of motion of noncommutative scalar field. This metric
displays a new horizon in addition to the original one associated with the
Schwarzschild black hole. The infinite red-shifting of the scalar field on the
new horizon determines the range of the noncommutativ space and explains the
relevant boundary condition for the field. This range enables us to calculate
the entropy of black hole as proportional to the area of its original horizon
along the same line as in 't Hooft's model, and the thickness of the brick wall
is found to be proportional to the thermal average of the noncommutative
space-time range. The Hawking temperature has been derived in this formalism.
The study here represents an attempt to reveal some physics beyond the brick
wall model.Comment: RevTeX, 5 pages, no figure
Carotenoid content and reflectance of yellow and red nuptial plumages in widowbirds (Euplectes spp.)
1. Ornamental carotenoid coloration is commonly based on several different pigments with different nutritional and metabolic constraints. The identification and quantification of carotenoid pigments is therefore crucial to the understanding of signal content and signal evolution. 2. In male widowbirds (Euplectes spp.), the striking yellow and red carotenoid colours have been measured by reflectance spectrometry and studied with respect to sexual selection through male contest competition, but their biochemical mechanisms have not been analysed. 3. Here we use reflectance analysis and high performance liquid chromatography (HPLC) to describe the species-specific colours and plumage carotenoids in three widowbird species: yellow-mantled widowbird (YMW) Euplectes macrourus, red-shouldered widowbird (RSW) E. axillaris and red-collared widowbird (RCW) E. ardens. 4. YMW yellow (âhueâ colorimetric λR50 = 522 nm) derives from the two âdietary yellowâ xanthophylls lutein and zeaxanthin, together with small amounts of âderived yellowâ pigments (3âČ-dehydrolutein and canary xanthophylls). 5. RCW red (λR50 = 574 nm) is achieved by the addition of low concentrations of âderived red â 4-keto-carotenoids, notably α- and ÎČ-doradexanthin and canthaxanthin. 6. RSW red (λR50 = 589 nm) is, in contrast, created by high concentrations of âdietary yellow â pigments (lutein, zeaxanthin) and âderived yellow â anhydrolutein, the latter only recently described in birds. 7. The two different mechanisms of producing red plumage are compared with other bird species and discussed with regard to costs and signal âhonestyâ
Continuity of the Maximum-Entropy Inference
We study the inverse problem of inferring the state of a finite-level quantum
system from expected values of a fixed set of observables, by maximizing a
continuous ranking function. We have proved earlier that the maximum-entropy
inference can be a discontinuous map from the convex set of expected values to
the convex set of states because the image contains states of reduced support,
while this map restricts to a smooth parametrization of a Gibbsian family of
fully supported states. Here we prove for arbitrary ranking functions that the
inference is continuous up to boundary points. This follows from a continuity
condition in terms of the openness of the restricted linear map from states to
their expected values. The openness condition shows also that ranking functions
with a discontinuous inference are typical. Moreover it shows that the
inference is continuous in the restriction to any polytope which implies that a
discontinuity belongs to the quantum domain of non-commutative observables and
that a geodesic closure of a Gibbsian family equals the set of maximum-entropy
states. We discuss eight descriptions of the set of maximum-entropy states with
proofs of accuracy and an analysis of deviations.Comment: 34 pages, 1 figur
Analysis of the vector and axialvector mesons with QCD sum rules
In this article, we study the vector and axialvector mesons with the
QCD sum rules, and make reasonable predictions for the masses and decay
constants, then calculate the leptonic decay widths. The present predictions
for the masses and decay constants can be confronted with the experimental data
in the future. We can also take the masses and decay constants as basic input
parameters and study other phenomenological quantities with the three-point
vacuum correlation functions via the QCD sum rules.Comment: 14 pages, 16 figure
Brane matter, hidden or mirror matter, their various avatars and mixings: many faces of the same physics
Numerous papers deal with the phenomenology related to photon-hidden photon
kinetic mixing and with the effects of a mass mixing on particle-hidden
particle oscillations. In addition, recent papers underline the existence of a
geometrical mixing between branes which would allow a matter swapping between
branes. These approaches and their phenomenologies are reminiscent of each
other but rely on different physical concepts. In the present paper, we suggest
there is no rivalry between these models, which are probably many faces of the
same physics. We discuss some phenomenological consequences of a global
framework.Comment: 9 pages. Typo corrected. Published in European Physical Journal
Age-specific mortality rate ratios in adolescents and youth aged 10-24 years living with perinatally versus nonperinatally acquired HIV
Objective: To measure mortality incidence rates and incidence rate ratios (IRR) in adolescents and youth living with perinatally acquired HIV (YPHIV) compared with those living with nonperinatally acquired HIV (YNPHIV), by region, by sex, and during the ages of 10-14, 15-19, and 20-24 years in IeDEA. Design and methods: All those with a confirmed HIV diagnosis, antiretroviral therapy (ART)-naive at enrollment, and who have post-ART follow-up while aged 10-24 years between 2004 and 2016 were included. We estimated post-ART mortality incidence rates and 95% confidence intervals (95% CI) per 100 person-years for YPHIV (enrolled into care <10 years of age) and YNPHIV (enrolled â„10 years and <25 years). We estimate mortality IRRs in a negative binomial regression model, adjusted for sex, region time-varying age, CD4+cell count at ART initiation (<350cells/ÎŒl, â„350cells/ÎŒl, unknown), and time on ART (<12 and â„12 months). Results: Overall, 104846 adolescents and youth were included: 21340 (20%) YPHIV (50% women) and 83506 YNPHIV (80% women). Overall mortality incidence ratios were higher among YNPHIV (incidence ratio: 2.3/100 person-years; 95% CI: 2.2-2.4) compared with YPHIV (incidence ratio: 0.7/100 person-years; 95% CI: 0.7-0.8). Among adolescents aged 10-19 years, mortality was lower among YPHIV compared with YNPHIV (all IRRs <1, ranging from 0.26, 95% CI: 0.13-0.49 in 10-14-year-old boys in the Asia-Pacific to 0.51, 95% CI: 0.30-0.87 in 15-19-year-old boys in West Africa). Conclusion: We report substantial amount of deaths occurring during adolescence. Mortality was significantly higher among YNPHIV compared to YPHIV. Specific interventions including HIV testing and early engagement in care are urgently needed to improve survival among YNPHIV
Measurement of the p-pbar -> Wgamma + X cross section at sqrt(s) = 1.96 TeV and WWgamma anomalous coupling limits
The WWgamma triple gauge boson coupling parameters are studied using p-pbar
-> l nu gamma + X (l = e,mu) events at sqrt(s) = 1.96 TeV. The data were
collected with the DO detector from an integrated luminosity of 162 pb^{-1}
delivered by the Fermilab Tevatron Collider. The cross section times branching
fraction for p-pbar -> W(gamma) + X -> l nu gamma + X with E_T^{gamma} > 8 GeV
and Delta R_{l gamma} > 0.7 is 14.8 +/- 1.6 (stat) +/- 1.0 (syst) +/- 1.0 (lum)
pb. The one-dimensional 95% confidence level limits on anomalous couplings are
-0.88 < Delta kappa_{gamma} < 0.96 and -0.20 < lambda_{gamma} < 0.20.Comment: Submitted to Phys. Rev. D Rapid Communication
Models of support for disclosure of HIV status to HIV-infected children and adolescents in resource-limited settings
Introduction: Disclosure of HIV status to HIV-infected children and adolescents is a major care challenge. We describe current site characteristics related to disclosure of HIV status in resource-limited paediatric HIV care settings within the International Epidemiology Databases to Evaluate AIDS (IeDEA) consortium. Methods: An online site assessment survey was conducted across the paediatric HIV care sites within six global regions of IeDEA. A standardized questionnaire was administered to the sites through the REDCap platform. Results: From June 2014 to March 2015, all 180 sites of the IeDEA consortium in 31 countries completed the online survey: 57% were urban, 43% were health centres and 86% were integrated clinics (serving both adults and children). Almost all the sites (98%) reported offering disclosure counselling services. Disclosure counselling was most often provided by counsellors (87% of sites), but also by nurses (77%), physicians (74%), social workers (68%), or other clinicians (65%). It was offered to both caregivers and children in 92% of 177 sites with disclosure counselling. Disclosure resources and procedures varied across geographical regions. Most sites in each region reported performing staff members' training on disclosure (72% to 96% of sites per region), routinely collecting HIV disclosure status (50% to 91%) and involving caregivers in the disclosure process (71% to 100%). A disclosure protocol was available in 14% to 71% of sites. Among the 143 sites (79%) routinely collecting disclosure status process, the main collection method was by asking the caregiver or child (85%) about the child's knowledge of his/her HIV status. Frequency of disclosure status assessment was every three months in 63% of the sites, and 71% stored disclosure status data electronically. Conclusion: The majority of the sites reported offering disclosure counselling services, but educational and social support resources and capacities for data collection varied across regions. Paediatric HIV care sites worldwide still need specific staff members' training on disclosure, development and implementation of guidelines for HIV disclosure, and standardized data collection on this key issue to ensure the long-term health and wellbeing of HIV-infected youth
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