Termite Distribution in Michigan

Subterranean termites have been present in Michigan for a long time. They were reported as being destructive to buildings in 1920 (Anonymous, 1961), and apparently damage done at that time was increasing over what had occurred earlier. Notwithstanding this long time presence of termites in the state a majority of the population still looks upon the termite as a strange insect most likely to be encountered in the South. All too many home owners and building proprietors as well as others are unacquainted with presence of termites in their areas. At the same time monetary loss due to termite attack is considerable. As an example, control costs and losses to structures in Tennessee due to termites in 1971 were reported (Anonymous, 1972) as over $8 million. Expenditures are less than this in Michigan but still substantial. Because of these facts it was felt that a wide cross-section of the public would benefit from knowledge of locations in Michigan where termites are present and most likely to cause damage. Unfortunately the general public is not aware that there are effective control methods to prevent damage where termites are a hazard. Retieulitermes flavipes (Kollar) is the most commonly encountered termite in Michigan. Other species found in the State are Reticulitermes arenincola Goellner and R. tibialis Banks. Areninocola is reported from the very southwest corner of the State and R. tibialis is known from scattered localities

Search for vertical stratification of metals in atmospheres of blue horizontal-branch stars

The observed abundance peculiarities of many chemical species relative to the expected cluster metallicity in blue horizontal-branch (BHB) stars presumably appear as a result of atomic diffusion in the photosphere. The slow rotation (typically $v\sin{i}<$ 10 km s$^{-1}$) of BHB stars with effective temperatures $T_{\rm eff}>$ 11,500 K supports this idea since the diffusion mechanism is only effective in a stable stellar atmosphere. In this work we search for observational evidence of vertical chemical stratification in the atmospheres of six hot BHB stars: B84, B267 and B279 in M15 and WF2-2541, WF4-3085 and WF4-3485 in M13. We undertake an abundance stratification analysis of the stellar atmospheres of the aforementioned stars, based on acquired Keck HIRES spectra. We have found from our numerical simulations that three stars (B267, B279 and WF2-2541) show clear signatures of the vertical stratification of iron whose abundance increases toward the lower atmosphere, while the other two stars (B84 and WF4-3485) do not. For WF4-3085 the iron stratification results are inconclusive. B267 also shows a signature of titanium stratification. Our estimates for radial velocity, $v\sin{i}$ and overall iron, titanium and phosphorus abundances agree with previously published data for these stars after taking the measurement errors into account. The results support the hypothesis regarding the efficiency of atomic diffusion in the stellar atmospheres of BHB stars with $T_{\rm eff}>$ 11,500 K.Comment: 8 pages, 12 figures, accepted for publication in Astronomy and Astrophysic

Stratification of the elements in the atmospheres of blue horizontal-branch stars

Blue horizontal-branch (BHB) stars with $T_{\rm eff}$ approximately larger than 11500 K show several observational anomalies. In globular clusters, they exhibit low rotational velocities, abundance anomalies (as compared to cluster abundances), photometric jumps and gaps and spectroscopic gravities lower than predicted by canonical models. It is commonly believed that the low rotational velocities of these stars permit atomic diffusion to be efficient in their atmosphere thereby causing the observed anomalies. Recent detections of vertical stratification of iron (and some other chemical elements) in several BHB stars concur with this framework. In this paper, improved model atmospheres that include the vertical stratification of the elements are applied to BHB stars to verify if they can explain their observational anomalies. The results from theoretical model atmospheres are consistent with the photometric jumps and gaps observed for BHB stars in globular clusters. It is found that iron stratification in the theoretical models and that obtained from observations have similar tendancies. Our results also show that the spectroscopic gravities obtained while using chemically homogeneous model atmospheres to fit observations are underestimated. These results significantly strengthen the belief that atomic diffusion is responsible for these BHB-star anomalies.Comment: 6 pages, 6 figure

Gender and Banking: Are Women Better Loan Officers?

We analyze gender differences associated with loan officer performance. Using a unique data set for a commercial bank in Albania over the period 1996 to 2006, we find that loans screened and monitored by female loan officers show statistically and economically significant lower default rates than loans handled by male loan officers. This effect comes in addition to a lower default rate of female borrowers and cannot be explained by sample selection, overconfidence of male loan officers or experience differences between female and male loan officers. Our results seem to be driven by differences in monitoring, as loan officers of different gender do not seem to screen borrowers differently based on observable borrower characteristics. This suggests that gender indeed matters in banking.Behavioral banking;loan officers;gender;loan default;monitoring;screening

Sex and Credit: Is There a Gender Bias in Microfinance?

This paper examines the effects of group identity in the credit market. Exploiting the quasirandom assignment of first-time borrowers to loan officers of a large Albanian lender, we test for own-gender bias in the loan officer-borrower match. We find that borrowers pay on average 29 basis points higher interest rates when paired with a loan officer of the other sex. The results indicate the presence of a taste-based rather than a statistical bias, as borrowers’ likelihood of going into arrears is independent of loan officer gender. Ending up with an opposite-sex loan officer also affects demand for credit, with borrowers being 11.5 percent less likely to return for a second loan. The bias is more pronounced when the social distance, as proxied by difference in age between the loan officer and the borrower, increases and when financial market competition declines. This is consistent with theories that predict a tastebased bias to be stronger when the psychological costs of being biased are lower and the discretion in setting interest rates is higher. Taken together, the findings suggest that owngender preferences can have substantial welfare effects.Identity;interest rates;gender;loan officers;microfinance

Si-induced superconductivity and structural transformations in DyRh4B4

DyRh4B4 has been known to crystallize in the primitive tetragonal (pt)-structure and to exhibit a ferromagnetic transition at 12 K, the highest magnetic transition temperature in the entire series of the RRh4B4 materials [1]. We show here that our silicon-added samples of the nominal composition DyRh4B4Si0.2 exhibit superconductivity below Tc ~ 4.5 K and an antiferromagnetic transition below TN ~ 2.7 K. The 12 K transition observed in the pt-DyRh4B4 is completely suppressed. Our annealed samples mainly consist of domains of the chemical composition DyRh3.9B4.2Si0.08. These domains contain two crystallographic phases belonging to the body-centred tetragonal (bct)-structure and the orthorhombic (o)-structure. We have reasons to suggest that superconductivity and antiferromagnetic ordering arise from bct- DyRh4B4 phase and, therefore, coexist below TN ~ 2.7 K.Comment: 11 pages, 6 figures, Accepted for publication in Journal of Alloys and Compound

On Time-Space Noncommutativity for Transition Processes and Noncommutative Symmetries

We explore the consequences of time-space noncommutativity in the quantum mechanics of atoms and molecules, focusing on the Moyal plane with just time-space noncommutativity ($[\hat{x}_\mu ,\hat{x}_\nu]=i\theta_{\mu\nu}$, \theta_{0i}\neqq 0, $\theta_{ij}=0$). Space rotations and parity are not automorphisms of this algebra and are not symmetries of quantum physics. Still, when there are spectral degeneracies of a time-independent Hamiltonian on a commutative space-time which are due to symmetries, they persist when \theta_{0i}\neqq 0; they do not depend at all on $\theta_{0i}$. They give no clue about rotation and parity violation when \theta_{0i}\neqq 0. The persistence of degeneracies for \theta_{0i}\neqq 0 can be understood in terms of invariance under deformed noncommutative ``rotations'' and ``parity''. They are not spatial rotations and reflection. We explain such deformed symmetries. We emphasize the significance of time-dependent perturbations (for example, due to time-dependent electromagnetic fields) to observe noncommutativity. The formalism for treating transition processes is illustrated by the example of nonrelativistic hydrogen atom interacting with quantized electromagnetic field. In the tree approximation, the $2s\to 1s +\gamma$ transition for hydrogen is zero in the commutative case. As an example, we show that it is zero in the same approximation for $\theta_{0i}\ne 0$. The importance of the deformed rotational symmetry is commented upon further using the decay $Z^0 \to 2\gamma$ as an example.Comment: 13 pages, revised version, references adde

Friedmann limits of rotating hypersurface-homogeneous dust models

The existence of Friedmann limits is systematically investigated for all the hypersurface-homogeneous rotating dust models, presented in previous papers by this author. Limiting transitions that involve a change of the Bianchi type are included. Except for stationary models that obviously do not allow it, the Friedmann limit expected for a given Bianchi type exists in all cases. Each of the 3 Friedmann models has parents in the rotating class; the k = +1 model has just one parent class, the other two each have several parent classes. The type IX class is the one investigated in 1951 by Goedel. For each model, the consecutive limits of zero rotation, zero tilt, zero shear and spatial isotropy are explicitly calculated.Comment: 39 pages, LaTeX, 1 postscript figure. Subjects: General relativity, exact solutions, cosmolog