Modelling the potential of rainwater harvesting in western Kenya using remote sensing and GIS techniques

Water scarcity is among the many problems faced today by many countries in the world, especially African countries. The Kakamega area in western Kenya is known for plenty of rainfall (around 2000 mm annually), however, rainwater harvesting (RHW) from roofs is not yet a common practice in the region. In this study, we determined the potential of RWH as an alternative or preferred source of safe water for domestic use. Spatial modelling techniques using amount of rainfall, census data and detailed information available from the classification of very high resolution QuickBird satellite imagery as input data were applied to implement various approaches. Four conceptual models were developed at three different levels of detail: the Kakamega-Nandi forests area (3900 km²), the QuickBird imagery covered area (473 km² of farmland) and Buyangu village (1.9 km²). The four models were implemented in ArcGIS ModelBuilder and reveal the potential of such spatially explicit simulations to guide planners and to demonstrate the benefits of RWH to the local people. In the Kakamega-Nandi forests area, it rains enough to meet the annual water demand of 7300 l per person almost throughout the entire area

A SILAC-based Approach Identifies Substrates of Caspase-dependent Cleavage upon TRAIL-induced Apoptosis

The extracellular ligand-induced extrinsic pathway of apoptosis is executed via caspase protease cascades that activate downstream effectors by means of site-directed proteolysis. Here we identify proteome changes upon the induction of apoptosis by the cytokine tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in a Jurkat T cell line. We detected caspase-dependent cleavage substrates by quantifying protein intensities before and after TRAIL induction in SDS gel slices. Apoptotic protein cleavage events are identified by a characteristic stable isotope labeling with amino acids in cell culture (SILAC) ratio pattern across gel slices that results from differential migration of the cleaved and uncleaved proteins. We applied a statistical test to define apoptotic substrates in the proteome. Our approach identified more than 650 of these cleaved proteins in response to TRAIL-induced apoptosis, including many previously unknown substrates and cleavage sites. Inhibitor treatment combined with triple SILAC demonstrated that the detected cleavage events were caspase dependent. Proteins located in the lumina of organelles such as mitochondria and endoplasmic reticulum were significantly underrepresented in the substrate population. Interestingly, caspase cleavage is generally observed in not only one but several members of stable complexes, but often with lower stoichiometry. For instance, all five proteins of the condensin I complex were cleaved upon TRAIL treatment. The apoptotic substrate proteome data can be accessed and visualized in the MaxQB database and might prove useful for basic and clinical research into TRAIL-induced apoptosis. The technology described here is extensible to a wide range of other proteolytic cleavage events

X-ray emission from the old pulsar B0950+08

We present the timing and spectral analyses of theXMM-newton data on the 17-Myr-old, nearby radio pulsar B0950+08. This observation revealed pulsations of the X-ray flux of the pulsar at its radio period. The pulse shape and pulsed fraction are apparently different at lower and higher energies of the observed 0.2-10 keV energy range, which suggests that the radiation cannot be explained by a single emission mechanism. The X-ray spectrum of the pulsar can be fitted with a power-law model with a photon index about 1.75 and an (isotropic) luminosity about 9.8e29 erg/s in the 0.2-10 keV. Better fits are obtained with two-component, power-law plus thermal, models with index of 1.30 and 9.7e29 erg/s for the power-law component that presumably originates from the pulsar's magnetosphere. The thermal component, dominating at E>0.7 keV, can be interpreted as radiation from heated polar caps on the neutron star surface covered with a hydrogen atmosphere. The inferred effective temperature, radius, and bolometric luminosity of the polar caps are about 1 MK, 250 m, and 3e29 erg/s. Optical through X-ray nonthermal spectrum of the pulsar can be described as a single power-law with index 1.3-1.4 for the two-component X-ray fit. The ratio of the nonthermal X-ray (1-10 keV) luminosity to the nonthermal optical (4000-9000 \AA) luminosity is within the range of 1e2-1e3 observed for younger pulsars, which suggests that the magnetospheric X-ray and optical emissions are powered by the same mechanism in all pulsars. An upper limit on the temperature of the bulk of the neutron star surface, inferred from the optical and X-ray data, is about 0.15 MK. We also analyze X-ray observations of several other old pulsars, B2224+65, J2043+2740, B0628-28, B1813-36, B1929+10, and B0823+26.Comment: To be published in ApJ. Nonthermal optical and X-ray luminosities of seven radio pulsars are updated and presented in a new Table. Figure 6 showing the ratios of the luminosities vs. spin-down energy is also update

A possible optical counterpart to the old nearby pulsar J0108-1431

The multi-wavelength study of old (>100 Myr) radio pulsars holds the key to understanding the long-term evolution of neutron stars, including the advanced stages of neutron star cooling and the evolution of the magnetosphere. Optical/UV observations are particularly useful for such studies because they allow one to explore both thermal and non-thermal emission processes. In particular, studying the optical/UV emission constrains temperature of the bulk of the neutron star surface, too cold to be measured in X-ray observations.Aim of this work is to identify the optical counterpart of the very old (166 Myr) radio pulsar J0108-1431. We have re-analyzed our original VLT observations (Mignani et al. 2003), where a very faint object was tentatively detected close to the radio position, near the edge of a field galaxy. We found that the backward extrapolation of the PSR J0108-1431 proper motion recently measured by CHANDRA(Pavlov et al. 2008) nicely fits the position of this object. Based on that, we propose it as a viable candidate for the optical counterpart to PSR J0108-1431. The object fluxes (U =26.4+/-0.3; B =27.9; V >27.8) are consistent with a thermal spectrum with a brightness temperature of 9X10^4 K (for R = 13 km at a distance of 130 pc), emitted from the bulk of the neutron star surface. New optical observations are required to confirm the optical identification of PSR J0108-1431 and measure its spectrum.Comment: 5 pages, 4 figures, submitted to A&

Comparing proportional compositions of geospatial technology-related programs at three universities

Today, graduates seek employment in a global marketplace, regardless of the country in which they studied. Comparing academic programs helps students, academics and employers to make informed decisions about study options, program offerings and the employment of recent graduates. In this study, we juxtapose geospatial technologyrelated programs at three universities located in Europe, Africa and America. Initially, the authors contributed information about these programs through a questionnaire comprising several open-ended questions about the origins and development of the respective programs. Subsequently, the proportional thematic compositions of programs at the three universities were compared. As expected, this study was not without challenges. From the outset, we struggled with agreeing on terminology and semantics. Results of the study indicate that there is not a one-size-fits-all strategy for establishing, shaping and sustaining such programs. Program composition is guided by many factors, including staff expertise, university politics, legislation, attractiveness to students,  technological developments, demands in the job market and requirements set by a professional body. Some of these factors are strongly influenced by the local (university) environment (e.g. staff expertise), others are of national relevance (e.g. legislation and a national professional body), while some apply globally (e.g. technological developments). The study illustrated how a comparison of proportional program composition can reveal significant differences and similarities that are not obvious when only content is compared. The compositional differences naturally result in graduates with different knowledge and skills that allow different career paths and meet different needs of the job market

Cooling of Neutron Stars: Two Types of Triplet Neutron Pairing

We consider cooling of neutron stars (NSs) with superfluid cores composed of neutrons, protons, and electrons (assuming singlet-state pairing of protons, and triplet-state pairing of neutrons). We mainly focus on (nonstandard) triplet-state pairing of neutrons with the $|m_J| = 2$ projection of the total angular momentum of Cooper pairs onto quantization axis. The specific feature of this pairing is that it leads to a power-law (nonexponential) reduction of the emissivity of the main neutrino processes by neutron superfluidity. For a wide range of neutron critical temperatures $T_{cn}$, the cooling of NSs with the $|m_J| = 2$ superfluidity is either the same as the cooling with the $m_J = 0$ superfluidity, considered in the majority of papers, or much faster. The cooling of NSs with density dependent critical temperatures $T_{cn}(\rho)$ and $T_{cp}(\rho)$ can be imitated by the cooling of the NSs with some effective critical temperatures $T_{cn}$ and $T_{cp}$ constant over NS cores. The hypothesis of strong neutron superfluidity with $|m_J| = 2$ is inconsistent with current observations of thermal emission from NSs, but the hypothesis of weak neutron superfluidity of any type does not contradict to observations.Comment: 10 pages, 6 figure

Neutral weak currents in nucleon superfluid Fermi liquids: Larkin-Migdal and Leggett approaches

Neutrino emission in processes of breaking and formation of nucleon Cooper pairs is calculated in the framework of the Larkin-Migdal and the Leggett approaches to the description of superfluid Fermi liquids at finite temperatures. We explain peculiarities of both approaches and explicitly demonstrate that they lead to the same expression for the emissivity in pair breaking and formation processes.Comment: 24 pages, 3 figure

Diquark Condensates and Compact Star Cooling

The effect of color superconductivity on the cooling of quark stars and neutron stars with large quark cores is investigated. Various known and new quark-neutrino processes are studied. As a result, stars being in the color flavor locked (CFL) color superconducting phase cool down extremely fast. Quark stars with no crust cool down too rapidly in disagreement with X-ray data. The cooling of stars being in the N_f =2 color superconducting (2SC) phase with a crust is compatible with existing X-ray data. Also the cooling history of stars with hypothetic pion condensate nuclei and a crust does not contradict the data.Comment: 10 pages, 5 figures, accepted for publication in Ap

Timing evolution of accreting strange stars

It has been suggested that the QPO phenomenon in LMXB's could be explained when the central compact object is a strange star. In this work we investigate within a standard model for disk accretion whether the observed clustering of spin frequencies in a narrow band is in accordance with this hypothesis. We show that frequency clustering occurs for accreting strange stars when typical values of the parameters of magnetic field initial strength and decay time, accretion rate are chosen. In contrast to hybrid star accretion no mass clustering effect is found.Comment: 10 pages, 3 figures, version accepted for publication in New Astronom

Time- and compartment-resolved proteome profiling of the extracellular niche in lung injury and repair

The extracellular matrix (ECM) is a key regulator of tissue morphogenesis and repair. However, its composition and architecture are not well characterized. Here, we monitor remodeling of the extracellular niche in tissue repair in the bleomycin-induced lung injury mouse model. Mass spectrometry quantified 8,366 proteins from total tissue and bronchoalveolar lavage fluid (BALF) over the course of 8 weeks, surveying tissue composition from the onset of inflammation and fibrosis to its full recovery. Combined analysis ofproteome, secretome, and transcriptome highlighted post-transcriptional events during tissue fibrogenesis and defined the composition of airway epithelial lining fluid. To comprehensively characterize the ECM, we developed a quantitative detergent solubility profiling (QDSP) method, which identified Emilin-2 and collagen-XXVIII as novel constituents of the provisional repair matrix. QDSP revealed which secreted proteins interact with the ECM, and showed drastically altered association of morphogens to the insoluble matrix upon injury. Thus, our proteomic systems biology study assigns proteins to tissue compartments and uncovers their dynamic regulation upon lung injury and repair, potentially contributing to the development of anti-fibrotic strategies