The effect of mineral and organic nutrient input on yields and nitrogen balances in western Kenya

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Agriculture, Ecosystems & Environment 214 (2015): 10-20, doi:10.1016/j.agee.2015.08.006.Soil fertility declines constrain crop productivity on smallholder farms in sub-Saharan Africa. Government and non-government organizations promote the use of mineral fertilizer and improved seed varieties to redress nutrient depletion and increase crop yields. Similarly, rotational cropping with nitrogen (N)-fixing legume cover crops or trees is promoted to improve soil fertility and crop yields. We examined maize grain yields and partial N balances on 24 smallholder maize farms in western Kenya, where interventions have increased access to agricultural inputs and rotational legume technologies. On these farms, mineral fertilizer inputs ranged from 0 to 161 kg N ha-1 (mean = 48 kg N ha-1), and maize grain yields ranged from 1-7 tons ha-1 (mean = 3.4 t ha-1). Partial N balances ranged from large losses (-112 kg N ha-1) to large gains (93 kg N ha-1)with a mean of -3 kg N ha-1. Maize grain yields increased significantly with N inputs (from fertilizer and legumes) in 2012 but not in 2013 when rainfall was lower. Nitrogen inputs of 40 kg N ha-1 were required to produce 3 tons of maize ha-1. N balances varied both among farms and between years, highlighting the importance of tracking inputs and outputs on multiple farms over multiple years before drawing conclusions about nutrient management, soil fertility outcomes and food security. The addition of N from legume rotations was a strong predictor of grain yields and positive N balances in lower-yielding farms in both years. This suggested that legume rotations may be particularly important for buffering yields from climate variability and maintaining N balances in low rainfall years.This research was funded by an Earth Institute at Columbia University Cross-Cutting Initiative Grant, a National Science Foundation PIRE grant (IIA-0968211), and by the Bill and Melinda Gates Foundation (Gates Special Initiative Grant)

The first direct measurement of ¹²C (¹²C,n) ²³Mg at stellar energies

Neutrons produced by the carbon fusion reaction ¹²C(¹²C,n)²³Mg play an important role in stellar nucleosynthesis. However, past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement that extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction ¹²C(¹²C,p)²³Na. The new reaction rate has been determined with a well-defined uncertainty that exceeds the precision required by astrophysics models. Using our constrained rate, we find that ¹²C(¹²C,n)²³Mg is crucial to the production of Na and Al in Pop-III Pair Instability Supernovae. It also plays a non-negligible role in the production of weak s-process elements as well as in the production of the important galacti

Sarcomas de partes blandas. Análisis de 42 casos

El objetivo de este estudio es valorar el pronóstico a largo plazo de una serie de pacientes tratados en nuestro hospital en relación con diversos factores clínicos, diagnósticos y terapéuticos que podrían condicionarlo. Se revisaron 123 pacientes tratado por tumores malignos de partes blandas entre los años 1979 y 1999, de estos solo 42 cumplieron las características para incluirles en nuestro estudio. Se valoró su evolución teniendo en cuenta las variables pronosticas identificadas en trabajos previamente publicados y nuestra propia experiencia y se realizó el estudio estadístico de las mismas. En el análisis estadístico del estudio se utilizó el programa SPSS versión 8.0WIN y se realizó el análisis de supervivencia mediante el método de Kaplan-Meier. El tiempo de supervivencia total descrito según este método para el total de los casos estudiados presenta una mediana de 33 meses con un error estándar de 8 y un intervalo de confianza del 95% de (17,49), el tiempo libre de enfermedad presenta una mediana de 9 meses con un error estándar de 2 y un intervalo de confianza del 95% de (6,12) y el tiempo de aparición de metástasis presenta una mediana de 26 meses con un error estándar de 5 y un intervalo de confianza del 95% de (17,35). A su vez se realizó el análisis bivariante de las múltiples variables pronosticas. El gran número de variables y la dispersión de la muestra hacen aconsejable estudios multicéntricos prospectivos más numerosos para obtener conclusiones definitivas sobre este tipo de tumores.The aim of this study is to evaluate the long-term prognosis of a series of patients treated in our hospital with regard to various clinical, diagnostic and therapeutic factors. A total of 123 patients who had been treated for malignant soft tissue tumours between 1979 and 1999 were reviewed. Of these, only 42 fulfilled the requirements to be included in our study. The outcome was evaluated taking into account prognostic variables identified in previously published studies and our own experience, and a statistical study of these factors as carried out with the Kaplan-Meier survival analysis method. The total survival time for all the cases studied was 33+8 (median + SE) months with a 95% confidence interval of 17.49 months. The time free of illness was 9+2 (median + SE) months with a 95% confidence interval of 6.12 months. The time-period until metastasis appeared was 26+5 (median + SE) months with a 95% confidence interval of 17.35 months. At the same time, the bivariant analysis of the many prognostic variables was performed. The high number of variables and the dispersion of the sample group suggest that it would be advisable to carry out more prospective, multicentric studies to reach definitive conclusions about this type of tumour

A compactness theorem for scalar-flat metrics on manifolds with boundary

Let (M,g) be a compact Riemannian manifold with boundary. This paper is concerned with the set of scalar-flat metrics which are in the conformal class of g and have the boundary as a constant mean curvature hypersurface. We prove that this set is compact for dimensions greater than or equal to 7 under the generic condition that the trace-free 2nd fundamental form of the boundary is nonzero everywhere.Comment: 49 pages. Final version, to appear in Calc. Var. Partial Differential Equation

Stellar 36,38^{36,38}Ar(n,γ)37,39(n,\gamma)^{37,39}Ar reactions and their effect on light neutron-rich nuclide synthesis

The $^{36}$Ar$(n,\gamma)^{37}$Ar ($t_{1/2}$ = 35 d) and $^{38}$Ar$(n,\gamma)^{39}$Ar (269 y) reactions were studied for the first time with a quasi-Maxwellian ($kT \sim 47$ keV) neutron flux for Maxwellian Average Cross Section (MACS) measurements at stellar energies. Gas samples were irradiated at the high-intensity Soreq applied research accelerator facility-liquid-lithium target neutron source and the $^{37}$Ar/$^{36}$Ar and $^{39}$Ar/$^{38}$Ar ratios in the activated samples were determined by accelerator mass spectrometry at the ATLAS facility (Argonne National Laboratory). The $^{37}$Ar activity was also measured by low-level counting at the University of Bern. Experimental MACS of $^{36}$Ar and $^{38}$Ar, corrected to the standard 30 keV thermal energy, are 1.9(3) mb and 1.3(2) mb, respectively, differing from the theoretical and evaluated values published to date by up to an order of magnitude. The neutron capture cross sections of $^{36,38}$Ar are relevant to the stellar nucleosynthesis of light neutron-rich nuclides; the two experimental values are shown to affect the calculated mass fraction of nuclides in the region A=36-48 during the weak $s$-process. The new production cross sections have implications also for the use of $^{37}$Ar and $^{39}$Ar as environmental tracers in the atmosphere and hydrosphere.Comment: 18 pages + Supp. Mat. (13 pages) Accepted for publication in Phys. Rev. Let

Breakup branches of Borromean beryllium-9

The breakup reaction 9Be(4He, 3α)n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in 9Be up to 12 MeV were populated and reconstructed through the measurement of the charged reaction products. It is proposed that limits on the spins and parities of the states can be derived from the way that they decay. Various breakup paths for excited states in 9Be have been explored including the 8Be(g.s.) + n, 8Be(2+) + n and 5He(g.s.) + 4He channels. By imposing the condition that the breakup proceeded via the 8Be ground state, clean excitation spectra for 9Be were reconstructed. The remaining two breakup channels were found to possess strongly-overlapping kinematic signatures and more sophisticated methods (referenced) are required to completely disentangle these other possibilities. Emphasis is placed on the development of the experimental analysis and the usefulness of Monte-Carlo simulations for this purpose

Evidence for a 3.8 MeV state in 9Be

The breakup reaction 9Be(4He,3a)n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in 9Be up to 8 MeV were populated and reconstructed through measurements of the charged reaction products. Evidence is given for a state in 9Be at 3.82-0.09+0.08 MeV with width=1240-90+270 keV. This is consistent with two recent measurements of a state with similar properties in the mirror nucleus 9B. An analysis of the reduced widths (Beg.s.8 channel) of this state along with the proposed mirror state has led to a firm limit of J<=7/2 and a tentative assignment of J^pi=1/2- or 3/2-

Independent measurement of the Hoyle state β\beta feeding from 12B using Gammasphere

Using an array of high-purity Compton-suppressed germanium detectors, we performed an independent measurement of the $\beta$-decay branching ratio from $^{12}\mathrm{B}$ to the second-excited (Hoyle) state in $^{12}\mathrm{C}$. Our result is $0.64(11)\%$, which is a factor $\sim 2$ smaller than the previously established literature value, but is in agreement with another recent measurement. This could indicate that the Hoyle state is more clustered than previously believed. The angular correlation of the Hoyle state $\gamma$ cascade has also been measured for the first time. It is consistent with theoretical predictions

Cytidine deaminase as a molecular target in cancer: an insight

Cancer is one of the leading causes of death globally. Although more than 400 varieties of cancer have been reported, based on cell lines, still the actual reason of all types of cancer is not very clear. Several internal and external factors have been identified and the study is ongoing. Up to now about 73 proteins have been identified that are capable to influence directly various phases of cancer including mutation, cell proliferation, invasion, angiogenesis, and metastasis. Cytidine deaminase is one of the important proteins that is responsible for various types of cancer that includes gastric, liver, biliary tract, bladder, breast, pancreatic ductal adenocarcinoma (PDAC) and so on. Two excellent inhibitors of cytidine deaminase are commercially available. A brief overview is presented in this advanced review. Any omission is completely unintentional