Two-Hop Interference Channels: Impact of Linear Time-Varying Schemes

We consider the two-hop interference channel (IC) with constant real channel coefficients, which consists of two source-destination pairs, separated by two relays. We analyze the achievable degrees of freedom (DoF) of such network when relays are restricted to perform scalar amplify-forward (AF) operations, with possibly time-varying coefficients. We show that, somewhat surprisingly, by providing the flexibility of choosing time-varying AF coefficients at the relays, it is possible to achieve 4/3 sum-DoF. We also develop a novel outer bound that matches our achievability, hence characterizing the sum-DoF of two-hop interference channels with time-varying AF relaying strategies.Comment: To appear in Proc. of ISIT 2013 (proof of lemma added

First report of Metarhizium anisopliae IP 46 pathogenicity in adult Anopheles gambiae s.s. and An. arabiensis (Diptera; Culicidae).

The entomopathogenic fungus Metarhizium anisopliae isolate IP 46, originating from a soil sample collected in 2001 in the Cerrado of Central Brazil, was tested for its ability to reduce the survival of adult male and female Anopheles gambiae s.s. and An. arabiensis mosquitoes. A 6-h exposure to the fungus coated on test paper at a concentration of 3.3 x 106 conidia cm-2 reduced the daily survival of both mosquito species (HR = 3.14, p < 0.001), with higher risk of dying in An. gambiae s.s relative to An. arabiensis (HR = 1.38, p < 0.001). Fungal sporulation was observed in >95% of mosquito cadavers in the treatment groups. The results indicate that M. anisopliae IP 46 has the potential to be a bio-control agent for African malaria vector species, and is a suitable candidate for further research and development

Entomopathogenic fungi, Metarhizium anisopliae and Beauveria bassiana reduce the survival of Xenopsylla brasiliensis larvae (Siphonaptera: Pulicidae).

Entomopathogenic fungi, particularly those belonging to the genera Metarhizium and Beauveria have shown great promise as arthropod vector control tools. These agents, however, have not been evaluated against flea vectors of plague. A 3-h exposure to the fungi coated paper at a concentration of 2 × 108 conidia m-2 infected >90% of flea larvae cadavers in the treatment groups. The infection reduced the survival of larvae that had been exposed to fungus relative to controls. The daily risk of dying was four- and over three-fold greater in larvae exposed to M. anisopliae (HR = 4, p<0.001) and B. bassiana (HR = 3.5, p<0.001) respectively. Both fungi can successfully infect and kill larvae of X. brasiliensis with a pooled median survival time (MST±SE) of 2±0.31 days post-exposure. These findings justify further research to investigate the bio-control potential of entomopathogenic fungi against fleas.\ud \u

Metallicities of 0.3<z<1.0 Galaxies in the GOODS-North Field

We measure nebular oxygen abundances for 204 emission-line galaxies with redshifts 0.3<z<1.0 in the Great Observatories Origins Deep Survey North (GOODS-N) field using spectra from the Team Keck Redshift Survey (TKRS). We also provide an updated analytic prescription for estimating oxygen abundances using the traditional strong emission line ratio, R_{23}, based on the photoionization models of Kewley & Dopita (2003). We include an analytic formula for very crude metallicity estimates using the [NII]6584/Halpha ratio. Oxygen abundances for GOODS-N galaxies range from 8.2< 12+log(O/H)< 9.1 corresponding to metallicities between 0.3 and 2.5 times the solar value. This sample of galaxies exhibits a correlation between rest-frame blue luminosity and gas-phase metallicity (i.e., an L-Z relation), consistent with L-Z correlations of previously-studied intermediate-redshift samples. The zero point of the L-Z relation evolves with redshift in the sense that galaxies of a given luminosity become more metal poor at higher redshift. Galaxies in luminosity bins -18.5<M_B<-21.5 exhibit a decrease in average oxygen abundance by 0.14\pm0.05 dex from z=0 to z=1. This rate of metal enrichment means that 28\pm0.07% of metals in local galaxies have been synthesized since z=1, in reasonable agreement with the predictions based on published star formation rate densities which show that ~38% of stars in the universe have formed during the same interval. (Abridged)Comment: AASTeX, 49 pages, 16 figures, accepted for publication in The Astrophysical Journa

A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves

We present an exhaustive, quantitative comparison of all of the known extinction curves in the Small and Large Magellanic Clouds (SMC and LMC) with our understanding of the general behavior of Milky Way extinction curves. The R_V dependent CCM relationship and the sample of extinction curves used to derive this relationship is used to describe the general behavior of Milky Way extinction curves. The ultraviolet portion of the SMC and LMC extinction curves are derived from archival IUE data, except for one new SMC extinction curve which was measured using HST/STIS observations. The optical extinction curves are derived from new (for the SMC) and literature UBVRI photometry (for the LMC). The near-infrared extinction curves are calculated mainly from 2MASS photometry supplemented with DENIS and new JHK photometry. For each extinction curve, we give R_V = A(V)/E(B-V) and N(HI) values which probe the same dust column as the extinction curve. We compare the properties of the SMC and LMC extinction curves with the CCM relationship three different ways: each curve by itself, the behavior of extinction at different wavelengths with R_V, and behavior of the extinction curve FM fit parameters with R_V. As has been found previously, we find that a small number of LMC extinction curves are consistent with the CCM relationship, but majority of the LMC and all of the SMC curves do not follow the CCM relationship. For the first time, we find that the CCM relationship seems to form a bound on the properties of all of the LMC and SMC extinction curves. This result strengthens the picture of dust extinction curves exhibit a continuum of properties between those found in the Milky Way and the SMC Bar. (abridged)Comment: 18 pages, 10 figures, ApJ in pres

Co-creation in service assemblages for service innovation : an empirical investigation

Co-creation could enhance service innovation (Perks, Gruber, and Edvardsson, 2012). Despite the research conducted on co-creation, the issue concerning how actors could form service system with high density still needs to be addressed (Michel, Vargo and Lusch, 2008). We conceptualized service system as an assemblage and investigated emergence and dynamic process of assemble and dissemble of service assemblages by drawing on theories of co-creation, affordance, task network and modularity and the notion of assemblage (Delanda, 2006). We developed a framework and empirically examined how to map the competences required for actors in a task network and how capacities could be optimally (re)configured as assemblages (clusters) for value co-creation. We demonstrated that the framework developed could be applied to formation, reformation of service assemblages for design of service offerings enabling optimal value co-creation

X-Ray Spectral Study of AGN Sources Content in Some Deep Extragalactic XMM-Newton Fields

We undertake a spectral study of a sample of bright X-ray sources taken from six XMM-Newton fields at high galactic latitudes, where AGN are the most populous class. These six fields were chosen such that the observation had an exposure time more than 60 ksec, had data from the EPIC-pn detector in the full-Frame mode and lying at high galactic latitude $|b| > 25^o$ . The analysis started by fitting the spectra of all sources with an absorbed power-law model, and then we fitted all the spectra with an absorbed power-law with a low energy black-body component model.The sources for which we added a black body gave an F-test probability of 0.01 or less (i.e. at 99% confidence level), were recognized as sources that display soft excess. We perform a comparative analysis of soft excess spectral parameters with respect to the underlying power-law one for sources that satisfy this criterion. Those sources, that do not show evidence for a soft excess, based on the F-test probability at a 99% confidence level, were also fitted with the absorbed power-law with a low energy black-body component model with the black-body temperature fixed at 0.1 and 0.2 keV. We establish upper limits on the soft excess flux for those sources at these two temperatures. Finally we have made use of Aladdin interactive sky atlas and matching with NASA/IPAC Extragalactic Database (NED) to identify the X-ray sources in our sample. For those sources which are identified in the NED catalogue, we make a comparative study of the soft excess phenomenon for different types of systems

“When I sleep under the net, nothing bothers me; I sleep well and I’m happy”: Senegal’s culture of net use and how inconveniences to net use do not translate to net abandonment

Abstract Background Despite recent advances in the fight against the disease, malaria remains a serious threat to the health and well-being of populations in endemic countries. The use of long-lasting insecticidal nets (LLIN) reduces contact between the vector and humans, thereby reducing transmission of the disease. LLINs have become an essential component of malaria control programmes worldwide. Methods The Culture of Net Use study used qualitative and quantitative methods in a longitudinal and iterative design over two phases, in order to capture changes in net use over a year and a half period and covering both dry and rainy seasons. Data were collected from a total of 56 households in eight regions to understand variations due to geographical, cultural, and universal coverage differences. At the time of the data collection, the universal coverage campaign had been completed in six of the eight regions (Dakar and Thies excluded). Results Perceived barriers to use were primarily related to the characteristics of the net itself, include shape, insecticide, and a variety of minority responses, such as perceived lack of mosquito density and being unaccustomed to using nets. Insecticide-related complaints found that insecticide did not present a significant barrier to use, but was cited as a nuisance. Feelings of suffocation continued to be the most commonly cited nuisance. Respondents who favoured the use of insecticide on nets appeared to be more aware of the health and malaria prevention benefits of the insecticide than those who perceived it negatively. Conclusion Despite prior evidence that barriers such as heat, shape, insecticide and perceived mosquito density contribute to non-use of LLINs in other countries, this study has shown that these factors are considered more as nuisances and that they do not consistently prevent the use of nets among respondents in Senegal. Of those who cited inconveniences with their nets, few were moved to stop using a net. Respondents from this study overcame these barriers and continue to value the importance of nets.http://deepblue.lib.umich.edu/bitstream/2027.42/109445/1/12936_2014_Article_3396.pd