Theory of pixel lensing towards M31 I: the density contribution and mass of MACHOs

POINT-AGAPE is an Anglo-French collaboration which is employing the Isaac Newton Telescope (INT) to conduct a pixel-lensing survey towards M31. In this paper we investigate what we can learn from pixel-lensing observables about the MACHO mass and fractional contribution in M31 and the Galaxy for the case of spherically-symmetric near-isothermal haloes. We employ detailed pixel-lensing simulations which include many of the factors which affect the observables. For a maximum MACHO halo we predict an event rate in V of up to 100 per season for M31 and 40 per season for the Galaxy. However, the Einstein radius crossing time is generally not measurable and the observed full-width half-maximum duration provides only a weak tracer of lens mass. Nonetheless, we find that the near-far asymmetry in the spatial distribution of M31 MACHOs provides significant information on their mass and density contribution. We present a likelihood estimator for measuring the fractional contribution and mass of both M31 and Galaxy MACHOs which permits an unbiased determination to be made of MACHO parameters, even from data-sets strongly contaminated by variable stars. If M31 does not have a significant population of MACHOs in the mass range 0.001-1 Solar masses strong limits will result from the first season of INT observations. Simulations based on currently favoured density and mass values indicate that, after three seasons, the M31 MACHO parameters should be constrained to within a factor four uncertainty in halo fraction and an order of magnitude uncertainty in mass (90% confidence). Interesting constraints on Galaxy MACHOs may also be possible. For a campaign lasting ten years, comparable to the lifetime of current LMC surveys, reliable estimates of MACHO parameters in both galaxies should be possible. (Abridged)Comment: 21 pages, 14 figures. Submitted to MNRA

Social Economic Factors Affecting Consumption of Sweet Potato Products: An Empirical Approach

The objective of the study was to analyze factors affecting consumption of value added products of sweet potato. The study was conducted in Shinyanga rural and Mwanza urban. Using cross sectional design, the study employed individual interviews, focused group discussions; review of relevant practical documents and discussions in data collection from a total of 200 surveyed households. Data collected was summarized using Statistical Package of Social Science (SPSS) windows versions 18.0.Analyses of the factors hypothesized to influence the consumption of sweet potatoes was carried out using multiple regression analysis. The goodness of fit of the model which is high as measured using coefficients of determination (R2). The higher value of R2 suggests that variables included in the model explained about 73% of the variations in the dependent variable. The F –Value is significant, indicating that the explanatory variables were statistically significant in explaining variation in the dependent variable. Furthermore, Variation Inflation Factor confirms absence of serious collinearity problem. Similarly, Durbin Watson test confirms the absence of autocorrelation. Furthermore, the data revealed that the sizes of land owned and education level are highly statistically significant at (p < 0.01) and statistically significant (p < 0.05) respectively. Hence there is need for farmers to increase the land area for sweet potatoes production to medium scale. Regarding to sweet potato prices it was found to vary from one node to another. However, there are a number of challenges facing the development of the sweet potato industry in Tanzania. The chronic shortage of seed is the most important challenge that needs to be dealt with (33.1%). Others were lack of capital (26.8%) unpredicted weather and pests/insect attack were the most critical challenges facing the subsector. Keywords: Sweet potato, value added products, consumption, Michembe, Matobolw

Resistenz gegenüber Online-Werbung - Einflussfaktoren und Konsequenzen der Werberesistenz im Internet

Die weltweit wachsende Akzeptanz des Mediums Internet führt zu einem steigenden Interesse der Werbeindustrie an der Nutzung des Mediums zur werblichen Kommunikation. Parallel wird in der sich verschärfenden wissenschaftlichen und öffentlichen Diskussion deutlich, dass beim Rezipienten erhebliche Widerstände gegen Werbung im Internet auftreten. In der Konsumentenverhaltensforschung mangelt es jedoch an wissenschaftlichen Untersuchungen, die sich mit der Thematik Werberesistenz detailliert auseinandersetzen. Die vorliegende Arbeit befasst sich daher zunächst mit der konzeptuellen Erarbeitung des Konstrukts Werberesistenz durch eine umfangreiche Analyse bisheriger Konzeptualisierungsansätze. Die Auswertung impliziert ein Resistenzverständnis, das sich durch die Kombination einer Einstellungs- und einer Verhaltenskomponente auszeichnet. In einem komplexen Hypothesensystem werden anschließend persönlichkeitsbezogene sowie vom Management beeinflussbare Determinanten der Werberesistenz modelliert. Die empirische Prüfung des Hypothesensystems erfolgt mittels der LISREL-Kausalanalyse (n=316). Die Ergebnisse der Studie bestätigen die Konzeptualisierung des Konstrukts Werberesistenz. Im hergeleiteten Bezugsrahmen kann die Relevanz der allgemeinen Werbeeinstellung, der persönlichkeitsbezogenen Merkmale Extraversion und Neurotizismus sowie die wahrgenommene Freiheitseinengung durch zu häufige Werbekontakte als Determinanten der Werberesistenz identifiziert werden. Abschließend werden konkrete Maßnahmen erläutert, wie das Marketingmanagement Resistenzen gegenüber OnlineWerbung unterbinden kann

Low absorption InP/InGaAs-MQW phase shifters for optical switching

InP/InGaAs-MQW phase shifters with low absorption loss and low electroabsorption loss have been realized. Phase shift efficiency for TE-polarized light at lambda =1.55 mu m was 6.8 degrees V/sup -1/ mm/sup -1/ with negligible absorption loss and at lambda =1.51 mu m the efficiency was 8.9 degrees V/sup -1/ mm/sup -1/ with 5 dB/cm absorption los

Formation and quantification of protein complexes between peroxisomal alcohol oxidase and GroEL

We have studied the use of yeast peroxisomal alcohol oxidase (AO) as a model protein for in vitro binding by GroEL. Dilution of denatured AO in neutral buffer leads to aggregation of the protein, which is prevented by the addition of GroEL. Formation of complexes between GroEL and denatured AO was demonstrated by a gel-shift assay using non-denaturing polyacrylamide gel electrophoresis, and quantified by laser-densitometry of the gels. In the presence of MgAMP-PNP or MgADP the affinity of GroEL for AO was enhanced. Under these conditions up to 70% of the purified GroEL formed a complex with this protein. Release was stimulated at room temperature by MgATP, and was further enhanced by addition of GroES.