5,741 research outputs found
Short Term Investment in Agriculture: Is there a Gender Bias?
Most developing countries strive to improve agricultural productivity by relaxing credit constraints, supplying better inputs, improving marketing and distribution. However the efficacy of these reforms needs to be examined in the context of the behavioral responses of farming households. This study examines gender biases within households that affect short-term investments in agriculture. The study utilizes data from ICRISATs village level studies in India (1975-85) to highlight the effects of child gender on the use of agricultural inputs. The main finding is that households with boys tend to use purchased inputs such as fertilizers and insecticides more intensively compared with households with girls. In general, household with boys also tend to have larger land holdings, and use animal and human labor to a greater extent than household with girls.Agricultural and Food Policy,
Isotropic properties of the photonic band gap in quasicrystals with low-index contrast
We report on the formation and development of the photonic band gap in
two-dimensional 8-, 10- and 12-fold symmetry quasicrystalline lattices of low
index contrast. Finite size structures made of dielectric cylindrical rods were
studied and measured in the microwave region, and their properties compared
with a conventional hexagonal crystal. Band gap characteristics were
investigated by changing the direction of propagation of the incident beam
inside the crystal. Various angles of incidence from 0 \degree to 30\degree
were used in order to investigate the isotropic nature of the band gap. The
arbitrarily high rotational symmetry of aperiodically ordered structures could
be practically exploited to manufacture isotropic band gap materials, which are
perfectly suitable for hosting waveguides or cavities.Comment: 16 pages, 7 figures, submitted to PR
EFFECTS AND DETERMINANTS OF MILD UNDERWEIGHT AMONG PRESCHOOL CHILDREN ACROSS COUNTRIES AND OVER TIME
Research on malnutrition typically focuses on severe cases, where anthropometric status falls below or above an extreme threshold. Such categorization is necessary for clinicians since mild cases may not justify intervention, but researchers could find that changes in mild malnutrition convey valuable information about mortality risk and health status. This paper focuses on changes in both mild and severe underweight in young children, as measured by 130 DHS surveys for 53 countries over a period from 1986 to 2007. We find that counting variance in all forms of underweight provides closer correlations with aggregate health outcomes (the underfive child mortality rate), and is more closely correlated to several influences of malnutrition (national income, gender equality and agricultural output). We conclude that the full distribution of nutritional status deserves greater attention, including in this case the prevalence of mild underweight among preschool children in developing countries.Underweight, weight-for-height, wasting, child mortality, FGT measures, DHS data
Preventing human immunodeficiency virus infection among sexual assault survivors in Cape Town, South Africa: an observational study.
We describe 131 South African sexual assault survivors offered HIV post-exposure prophylaxis (PEP). While the median days completed was 27 (IQR 27, 28), 34% stopped PEP or missed doses. Controlling for baseline symptoms, PEP was not associated with symptoms (OR = 1.30, 95% CI = 0.66, 2.64). Factors associated with unprotected sex included prior unprotected sex (OR = 6.46, 95% CI = 3.04, 13.74), time since the assault (OR = 1.33, 95% CI = 1.12, 1.57) and age (OR = 1.30, 95% CI = 1.08, 1.57). Trauma counseling was protective (OR = 0.18, 95% CI = 0.05, 0.58). Four instances of seroconversion were observed by 6 months (risk = 3.7%, 95% CI = 1.0, 9.1). Proactive follow-up is necessary to increase the likelihood of PEP completion and address the mental health and HIV risk needs of survivors. Adherence interventions and targeted risk reduction counseling should be provided to minimize HIV acquisition
Epirubicin With Cyclophosphamide Followed by Docetaxel With Trastuzumab and Bevacizumab as Neoadjuvant Therapy for HER2-Positive Locally Advanced Breast Cancer or as Adjuvant Therapy for HER2-Positive Pathologic Stage III Breast Cancer: A Phase II Trial of the NSABP Foundation Research Group, FB-5
Background The purpose of this study was to determine the cardiac safety and clinical activity of trastuzumab and bevacizumab with docetaxel after epirubicin with cyclophosphamide (EC) in patients with HER2-positive locally advanced breast cancer (LABC) or pathologic stage 3 breast cancer (PS3BC). Patients and Methods Patients received every 3 week treatment with 4 cycles of EC (90/600 mg/m2) followed by 4 cycles of docetaxel (100 mg/m2). Targeted therapy with standard-dose trastuzumab with bevacizumab 15 mg/kg was given for a total of 1 year. Coprimary end points were (1) rate of cardiac events (CEs) in all patients defined as clinical congestive heart failure with a significant decrease in left ventricular ejection fraction or cardiac deaths; and (2) pathologic complete response (pCR) in breast and nodes in the neoadjuvant cohort. An independent cardiac review panel determined whether criteria for a CE were met. Results A total of 105 patients were accrued, 76 with LABC treated with neoadjuvant therapy and 29 with PS3BC treated with adjuvant therapy. Median follow-up was 59.2 months. Among 99 evaluable patients for cardiac safety, 4 (4%; 95% confidence interval [CI], 1.1%-10.0%) met CE criteria. The pCR percentage in LABC patients was 46% (95% CI, 34%-59%). Five-year recurrence-free survival (RFS) and overall survival (OS) for all patients was 79.9% and 90.8%, respectively. Conclusion The regimen met predefined criteria for activity of interest with an acceptable rate of CEs. Although the pCR percentage was comparable with chemotherapy regimens with trastuzumab alone the high RFS and OS are of interest in these high-risk populations
GeneLink: a database to facilitate genetic studies of complex traits
BACKGROUND: In contrast to gene-mapping studies of simple Mendelian disorders, genetic analyses of complex traits are far more challenging, and high quality data management systems are often critical to the success of these projects. To minimize the difficulties inherent in complex trait studies, we have developed GeneLink, a Web-accessible, password-protected Sybase database. RESULTS: GeneLink is a powerful tool for complex trait mapping, enabling genotypic data to be easily merged with pedigree and extensive phenotypic data. Specifically designed to facilitate large-scale (multi-center) genetic linkage or association studies, GeneLink securely and efficiently handles large amounts of data and provides additional features to facilitate data analysis by existing software packages and quality control. These include the ability to download chromosome-specific data files containing marker data in map order in various formats appropriate for downstream analyses (e.g., GAS and LINKAGE). Furthermore, an unlimited number of phenotypes (either qualitative or quantitative) can be stored and analyzed. Finally, GeneLink generates several quality assurance reports, including genotyping success rates of specified DNA samples or success and heterozygosity rates for specified markers. CONCLUSIONS: GeneLink has already proven an invaluable tool for complex trait mapping studies and is discussed primarily in the context of our large, multi-center study of hereditary prostate cancer (HPC). GeneLink is freely available at
Ultrafast cooling reveals microsecond-scale biomolecular dynamics
The temperature-jump technique, in which the sample is rapidly heated by a powerful laser pulse, has been widely used to probe the fast dynamics of folding of proteins and nucleic acids. However, the existing temperature-jump setups tend to involve sophisticated and expensive instrumentation, while providing only modest temperature changes of ~10–15 °C, and the temperature changes are only rapid for heating, but not cooling. Here we present a setup comprising a thermally conductive sapphire substrate with light-absorptive nano-coating, a microfluidic device and a rapidly switched moderate-power infrared laser with the laser beam focused on the nano-coating, enabling heating and cooling of aqueous solutions by ~50 °C on a 1-μs time scale. The setup is used to probe folding and unfolding dynamics of DNA hairpins after direct and inverse temperature jumps, revealing low-pass filter behaviour during periodic temperature variations
Magnetic interactions in transition metal doped ZnO : An abinitio study
We calculate the nature of magnetic interactions in transition-metal doped
ZnO using the local spin density approximation and LSDA+\textit{U} method of
density functional theory. We investigate the following four cases: (i) single
transition metal ion types (Cr, Mn, Fe, Co, Ni and Cu) substituted at Zn sites,
(ii) substitutional magnetic transition metal ions combined with additional Cu
and Li dopants, (iii) substitutional magnetic transition metal ions combined
with oxygen vacancies and (iv) pairs of magnetic ion types (Co and Fe, Co and
Mn, etc.). Extensive convergence tests indicate that the calculated magnetic
ground state is unusually sensitive to the k-point mesh and energy cut-off, the
details of the geometry optimizations and the choice of the
exchange-correlation functional. We find that ferromagnetic coupling is
sometimes favorable for single type substitutional transition metal ions within
the local spin density approximation. However, the nature of magnetic
interactions changes when correlations on the transition-metal ion are treated
within the more realistic LSDA + \textit{U} method, often disfavoring the
ferromagnetic state. The magnetic configuration is sensitive to the detailed
arrangement of the ions and the amount of lattice relaxation, except in the
case of oxygen vacancies when an antiferromagnetic state is always favored.Comment: 11 pages, 17 figure
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