581 research outputs found
New risks and opportunities for food security: scenario analyses for 2015 and 2050
"Given the number of undernourished people in the developing world and the increasingly complex risks to food security, policymakers are faced with an enormous agenda. Freeing people from hunger will require more and better-targeted investments, innovations, and policy actions, driven by a keen understanding of the dynamic risks and forces that shape the factors affecting people's access to food and the links with nutrition. The International Food Policy Research Institute's (IFPRI's) International Model for Policy Analysis of Agricultural Commodities and Trade (IMPACT) provides insight into the management of these risks through appropriate policy actions. By projecting future global food scenarios to 2050, IMPACT explores the potential implications of policy action and inaction in several main risk areas as well as the effects on child malnutrition in the developing world, commodity prices, demand, cereal yields, production, and net trade. In the progressive policy actions scenario, which assumes increased investment in rural development, health, education, and agricultural research and development, developing country governments and the international community are able to dramatically reduce the number of food-insecure people, leading to a worldwide decline in hunger. Under these conditions, Latin America and China are able to virtually eliminate child malnutrition by 2050. Bolstered by the development and dissemination of improved technologies and better infrastructure, crop production and yields increase in developing countries. Notably, the bulk of the growth in production is driven by yield increases rather than by expanding land area. Spurred by growth in the agricultural sector, average incomes in developing countries increase. Rising incomes bolster demand for high-value agricultural products, such as meat, dairy, and fruits and vegetables; global livestock production more than doubles, for example. Average per capita calorie supplies for developing countries exceed 3,400 per day, well in excess of minimum requirements. The policy failure scenario assumes greater political discord and more extensive agricultural protectionism, together with the failure of policies to deal with food emergencies related to conflict. Slow growth and trade restrictions lead to stagnation in average per capita calorie availability, which remains only slightly above minimum requirements until after 2030, when availability increases. In addition, crucial investments in agriculture, rural development, and poverty reduction are forgone or displaced. Because of limited investment in agricultural research and technology, this scenario has a high level of crop area expansion as a result of relatively rapid population growth and slim yield improvements in developing countries. This scenario also results in flat maize prices, declining per capita cereal demand, falling beef prices, and relatively flat meat demand. As a result of the policies in this scenario, the number of malnourished children in developing countries rises between 1997 and 2015, after which there are only modest declines. In the technology and natural resource management failure scenario, yield growth falls even more than under the preceding scenario, forcing farmers to move into marginal producing areas, which causes a more rapid expansion of cereal area into less productive land that does not compensate for the yield shortfalls (and causes environmental degradation). As a result, cereal prices rise substantially through 2030 and then fall off only gradually. Beef and other meat prices, which are affected by the price of feed, follow a similar pattern. Developing-country per capita calorie availability is essentially unchanged over 1997–2050 and remains at a barely adequate average level. Given unequal access to the food that is available, millions of people actually consume less than the minimum. The occurrence of child undernourishment is even higher than under the policy failure scenario in all developing-country regions. Overall, the technology and natural resource management failure scenario results in the worst impact on food security and child malnourishment in the developing world. The progressive policy scenario outlines several of the most crucial positive steps. National governments and the international community must assume a new focus on agricultural growth and rural development, along with increasing their investments in education, social services, and health. Policies to encourage synergistic growth in the nonfarm sectors are also needed to spur broad-based economic growth. Underpinning these strategies and research agendas must be a firm commitment to reducing hunger and improving the welfare of the world's undernourished people." From Authors' Executive SummaryImpact model, Caloric intake, Safety nets,
Impact of 6 month conjugated equine estrogen versus estradiol-treatment on biomarkers and enriched gene sets in healthy mammary tissue of non-human primates.
OBJECTIVE
To identify distinctly regulated gene markers and enriched gene sets in breast tissue of cynomolgus monkeys (Macaca fascicularis) treated for six months with either conjugated equine estrogens (CEE) or estradiol (E2) by analysis of corresponding mRNA levels of genes associated with breast development, carcinogenesis, apoptosis and immune regulation. Additionally, translation of three nuclear markers was analyzed.
METHODS
RNA from breast biopsies and necropsies was isolated from two independent study trials from Ethun et al. (CEE) and Foth et al. (E2) after 6 month of treatment duration. RNA was subjected to qRT-PCR and MicroArray analysis. Immunohistochemical stainings were performed for the estrogen receptor alpha subunit (ERa), the progesterone receptor (PGR) and the proliferation marker Ki67.
RESULTS
We identified a total of 36 distinctly enriched gene sets. Thirty-one were found in the CEE treatment group and five were found in the E2 treatment group, with no overlap. Furthermore, two individual genes IGFBP1 and SGK493 were upregulated in CEE treated animals. Additional targeted qRT-PCR analysis of ten specific estrogen-related genes showed upregulation of three genes (TFF1, PGR and GREB1) after CEE treatment, respectively one gene (TFF1) after E2 treatment. Immunohistochemical stains of breast biopsies showed a significant increase in expression of the PGR marker after CEE treatment.
CONCLUSIONS
In this study we identified enriched gene sets possibly induced by CEE or E2 treatment in various processes associated with cancer biology and immunology. This preliminary translational data supports the concept that different estrogen types have different effects on healthy breast tissue and may help generate hypotheses for future research
Ponderomotive effects in multiphoton pair production
The Dirac-Heisenberg-Wigner formalism is employed to investigate
electron-positron pair production in cylindrically symmetric but otherwise
spatially inhomogeneous, oscillating electric fields. The oscillation
frequencies are hereby tuned to obtain multiphoton pair production in the
nonperturbative threshold regime. An effective mass as well as a
trajectory-based semi-classical analysis are introduced in order to interpret
the numerical results for the distribution functions as well as for the
particle yields and spectra. The results, including the asymptotic particle
spectra, display clear signatures of ponderomotive forces.Comment: 9 pages, 3 Tables, 3 Figure
Morinda citrifolia (Noni) Juice Augments Mammary Gland Differentiation and Reduces Mammary Tumor Growth in Mice Expressing the Unactivated c-erbB2 Transgene
Morinda citrifolia (noni) is reported to have many beneficial properties, including on immune, inflammatory, quality of life, and cancer endpoints, but little is known about its ability to prevent or treat breast cancer. To test its anticancer potential, the effects of Tahitian Noni Juice (TNJ) on mammary carcinogenesis were examined in MMTV-neu transgenic mice. Mammary tumor latency, incidence, multiplicity, and metastatic incidence were unaffected by TNJ treatment, which suggests that it would not increase or decrease breast cancer risk in women taking TNJ for its other benefits. However, noni may be useful to enhance treatment responses in women with existing HER2/neu breast cancer since TNJ resulted in significant reductions in tumor weight and volume and in longer tumor doubling times in mice. Remarkably, its ability to inhibit the growth of this aggressive form of cancer occurred with the mouse equivalent of a recommended dose for humans (<3 oz/day). A 30-day treatment with TNJ also induced significant changes in mammary secondary ductule branching and lobuloalveolar development, serum progesterone levels, and estrous cycling. Additional studies investigating TNJ-induced tumor growth suppression and modified reproductive responses are needed to characterize its potential as a CAM therapy for women with and without HER2+ breast cancer
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A role for foregut tyrosine metabolism in glucose tolerance
Objective: We hypothesized that DA and L-DOPA derived from nutritional tyrosine and the resultant observed postprandial plasma excursions of L-DOPA and DA might affect glucose tolerance via their ability to be taken-up by beta cells and inhibit glucose-stimulated b-cell insulin secretion.
Methods: To investigate a possible circuit between meal-stimulated 3,4-dihydroxy-L-phenylalanine (L-DOPA) and dopamine (DA) production in the GI tract and pancreatic b-cells, we: 1) mapped GI mucosal expression of tyrosine hydroxylase (TH) and aromatic amino acid decarboxylase (AADC); 2) measured L-DOPA and DA content of GI mucosal tissues following meal challenges with different L-tyrosine (TYR) content, 3) determined whether meal TYR content impacts plasma insulin and glucose excursions; and 4) characterized postprandial plasma excursions of L-DOPA and DA in response to meal tyrosine content in rodents and a population of bariatric surgery patients. Next, we characterized: 1) the metabolic transformation of TYR and L-DOPA into DA in vitro using purified islet tissue; 2) the metabolic transformation of orally administrated stable isotope labeled TYR into pancreatic DA, and 3) using a nuclear medicine technique, we studied endocrine beta cells in situ release and binding of DA in response to a glucose challenge. Results: We demonstrate in rodents that intestinal content and circulatory concentrations L-DOPA and DA, plasma glucose and insulin are responsive to the tyrosine (TYR) content of a test meal. Intestinal expression of two enzymes, Tyrosine hydroxylase (TH) and Aromatic Amino acid Decarboxylase (AADC), essential to the transformation of TYR to DA was mapped and the metabolism of metabolism of TYR to DA was traced in human islets and a rodent beta cell line in vitro and from gut to the pancreas in vivo. Lastly, we show that b cells secrete and bind DA in situ in
response to glucose stimulation.
Conclusions: We provide proof-of-principle evidence for the existence of a novel postprandial circuit of glucose homeostasis dependent on nutritional tyrosine. DA and L-DOPA derived from nutritional tyrosine may serve to defend against hypoglycemia via inhibition of glucosestimulated
b-cell insulin secretion as proposed by the anti-incretin hypothesis
Sphalerons in Two Higgs Doublet Theories
We undertake a comprehensive investigation of the properties of the sphaleron
in electroweak theories with two Higgs doublets. We do this in as
model-independent a way as possible: by exploring the physical parameter space
described by the masses and mixing angles of the Higgs particles. If there is a
large split in the masses of the neutral Higgs particles, there can be several
sphaleron solutions, distinguished by their properties under parity and the
behaviour of the Higgs field at the origin. In general, these solutions appear
in parity conjugate pairs and are not spherically symmetric, although the
departure from spherical symmetry is small. Including CP violation in the Higgs
potential can change the energy of the sphaleron by up to 14 percent for a
given set of Higgs masses, with significant implications for the baryogenesis
bound on the mass of the lightest Higgs
Beam test results for the FiberGLAST instrument
The FiberGLAST scintillating fiber telescope is a large-area instrument concept for NASA\u27s GLAST program. The detector is designed for high-energy gamma-ray astronomy, and uses plastic scintillating fibers to combine a photon pair tracking telescope and a calorimeter into a single instrument. A small prototype detector has been tested with high energy photons at the Thomas Jefferson National Accelerator Facility. We report on the result of this beam test, including scintillating fiber performance, photon track reconstruction, angular resolution, and detector efficiency
Development and testing of a fiber/multianode photomultiplier system for use on FiberGLAST
A scintillating fiber detector is currently being studied for the NASA Gamma-Ray Large Area Space Telescope (GLAST) mission. This detector utilizes modules composed of a thin converter sheet followed by an x, y plane of scintillating fibers to examine the shower of particles created by high energy gamma-rays interacting in the converter material. The detector is composed of a tracker with 90 such modular planes and a calorimeter with 36 planes. The two major component of this detector are the scintillating fibers and their associated photodetectors. Here we present current status of development and test result of both of these. The Hamamatsu R5900-00-M64 multianode photomultiplier tube (MAPMT) is the baseline readout device. A characterization of this device has been performed including noise, cross- talk, gain variation, vibration, and thermal/vacuum test. A prototype fiber/MAPMT system has been tested at the Center for Advanced Microstructures and Devices at Louisiana State University with a photon beam and preliminary results are presented
String windings in the early universe
We study string dynamics in the early universe. Our motivation is the
proposal of Brandenberger and Vafa, that string winding modes may play a key
role in decompactifying three spatial dimensions. We model the universe as a
homogeneous but anisotropic 9-torus filled with a gas of excited strings. We
adopt initial conditions which fix the dilaton and the volume of the torus, but
otherwise assume all states are equally likely. We study the evolution of the
system both analytically and numerically to determine the late-time behavior.
We find that, although dynamical evolution can indeed lead to three large
spatial dimensions, such an outcome is not statistically favored.Comment: 26 pages, LaTeX, 4 eps figure
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