Optimization of resource allocation can explain the temporal dynamics and honesty of sexual signals

In species in which males are free to dynamically alter their allocation to sexual signaling over the breeding season, the optimal investment in signaling should depend on both a male’s state and the level of competition he faces at any given time. We developed a dynamic optimization model within a game‐theoretical framework to explore the resulting signaling dynamics at both individual and population levels and tested two key model predictions with empirical data on three‐spined stickleback (Gasterosteus aculeatus) males subjected to dietary manipulation (carotenoid availability): (1) fish in better nutritional condition should be able to maintain their signal for longer over the breeding season, resulting in an increasingly positive correlation between nutritional status and signal (i.e., increasing signal honesty), and (2) female preference for more ornamented males should thus increase over the breeding season. Both predictions were supported by the experimental data. Our model shows how such patterns can emerge from the optimization of resource allocation to signaling in a competitive situation. The key determinants of the honesty and dynamics of sexual signaling are the condition dependency of male survival, the initial frequency distribution of nutritional condition in the male population, and the cost of signaling

Optical matrix elements in tight-binding models with overlap

We investigate the effect of orbital overlap on optical matrix elements in empirical tight-binding models. Empirical tight-binding models assume an orthogonal basis of (atomiclike) states and a diagonal coordinate operator which neglects the intra-atomic part. It is shown that, starting with an atomic basis which is not orthogonal, the orthogonalization process induces intra-atomic matrix elements of the coordinate operator and extends the range of the effective Hamiltonian. We analyze simple tight-binding models and show that non-orthogonality plays an important role in optical matrix elements. In addition, the procedure gives formal justification to the nearest-neighbor spin-orbit interaction introduced by Boykin [Phys. Rev \textbf{B} 57, 1620 (1998)] in order to describe the Dresselahaus term which is neglected in empirical tight-binding models.Comment: 16 pages 6 figures, to appear in Phys. Rev.

P-wave Pairing and Colossal Magnetoresistance in Manganese Oxides

We point out that the existing experimental data of most manganese oxides show the {\sl frustrated} p-wave superconducting condensation in the ferromagnetic phase in the sense that the superconducting coherence is not long enough to cover the whole system. The superconducting state is similar to the $A_{1}$ state in superfluid He-3. The sharp drop of resistivity, the steep jump of specific heat, and the gap opening in tunneling are well understood in terms of the p-wave pairing. In addition, colossal magnetoresistance (CMR) is naturally explained by the superconducting fluctuations with increasing magnetic fields. The finite resistivity may be due to some magnetic inhomogeneities. This study leads to the possibility of room temperature superconductivity.Comment: LaTex, 14 pages, For more information, please send me an e-mail. e-mail adrress : [email protected]

Alternate Site Selection Process for the Falls City, Texas, Umtra Project

This evaluation of possible alternate disposal sites for the Falls City Uranium Mill Tailings Remediation Act (UMTRA) site in southeastern Texas (fig. 1) was undertaken in response to the requirements promulgated by the U.S. Department of Energy (DOE) for the remediation of UMTRA sites in accordance with the Uranium Mill Tailings Radiation Control Act of 1978. Primary objectives of this report are to (1) describe the general geology and hydrology of the areas that have been identified as containing potential alternate tailings sites and (2) describe the systematic process utilized to identify those areas that may contain potential alternate tailings disposal sites. The alternate site selection process employed for the Falls City site generally follows the format established in the 1988 UMTRA-DOE/AL Document 200129.0007 R-4 titled "Alternate Site Selection Process for UMTRA Project Sites." Implementation of the final step of the alternate site selection process as described in the 1988 UMTRA-DOE document would, however, require the collection of detailed, site-specific lithologic and hydrologic data, and this is beyond the scope of the present study. The site selection process used in the current study comprises three distinct phases: (1) designation of the search region and identification of the geologic formations exposed within this region; (2) screening of geologic units within the search region based upon broad geologic characteristics; and (3) application of geologic, hydrologic, environmental, and engineering criteria to the formation(s) not excluded by phase two of the process in order to identify the less favorable outcrop areas within these formations. Implementation of this three-phase process reduced the original 7,850 mi2 alternate site search region to a final region of interest of less than 30 mi2. The geologic and hydrologic characteristics of the final region of interest suggest that it may contain one or more alternate tailings storage sites.Bureau of Economic Geolog

Response of a particle in a one-dimensional lattice to an applied force: Dynamics of the effective mass

We study the behaviour of the expectation value of the acceleration of a particle in a one-dimensional periodic potential when an external homogeneous force is suddenly applied. The theory is formulated in terms of modified Bloch states that include the interband mixing induced by the force. This approach allows us to understand the behaviour of the wavepacket, which responds with a mass that is initially the bare mass, and subsequently oscillates around the value predicted by the effective mass. If Zener tunneling can be neglected, the expression obtained for the acceleration of the particle is valid over timescales of the order of a Bloch oscillation, which are of interest for experiments with cold atoms in optical lattices. We discuss how these oscillations can be tuned in an optical lattice for experimental detection.Comment: 15 pages, 12 figure

Environmental effects shape the maternal transfer of carotenoids and vitamin E to the yolk.

This is the final version of the article. Available from BioMed Central via the DOI in this record.UNLABELLED: INTRODUCTION: Maternal effects occur when the phenotype of the offspring is influenced by the phenotype of the mother, which in turn depends on her heritable state as well as on influences from the current and past environmental conditions. All of these pathways may, therefore, form significant sources of variation in maternal effects. Here, we focused on the maternal transfer of carotenoids and vitamin E to the egg yolk, using canaries as a model species. Maternal yolk carotenoids and vitamin E are known to generate significant phenotypic variation in offspring, representing examples of maternal effects. We studied the intra-individual consistency in deposition patterns across two years and the mother-daughter resemblance across two generations in order to estimate the level of heritable variation. The effects of the current environmental conditions were studied via a food supplementation experiment, while the consequences of past environmental conditions were estimated on the basis of the early growth trajectories. RESULTS: There was a significant effect of the current environmental conditions on the yolk carotenoid and vitamin E deposition, but this effect varied between antioxidant components. The deposition of yolk carotenoids and vitamin E were linked to the process of yolk formation. Past environmental conditions did not contribute to the variation in yolk carotenoid and vitamin E levels nor did we find significant heritable variation. CONCLUSIONS: The transfer of carotenoids or vitamin E may be an example where current environmental variation is largely passed from the mother to the offspring, despite the numerous intermediate physiological steps that are involved. Differences in the effect of the environmental conditions as experienced by the mother during laying may be due to differences in availability as well as physiological processes such as competitive exclusion or selective absorption.All experiments have been conducted according to Belgian legislation for animal experimentation (permit number 2006–19 and 2008–26). We thank Peter Scheys and Geert Eens for their assistance with taking care of the birds, and four anonymous reviewers provided valuable comments, which helped to improve the manuscript. WM was supported by FWO Flanders Belgium (1503307 and 1503307 N) and by the University of Antwerp (KP BOF UA 2006, 2008). JV by the Institute for the Promotion of Innovation through Science and Technology (IWT) in Flanders, ME was supported by the University of Antwerp and FWO Flanders. JDB was supported by a Royal Society University Research Fellowship

Subsurface Capture of Carbon Dioxide

A process and apparatus of separating CO.sub.2 gas from industrial off-gas source in which the CO.sub.2 containing off-gas is introduced deep within an injection well. The CO.sub.2 gases are dissolved in the, liquid within the injection well while non-CO.sub.2 gases, typically being insoluble in water or brine, are returned to the surface. Once the CO.sub.2 saturated liquid is present within the injection well, the injection well may be used for long-term geologic storage of CO.sub.2 or the CO.sub.2 saturated liquid can be returned to the surface for capturing a purified CO.sub.2 gas

Small Leaf Mid-Rib Xylem Related to Leaf Freeze Tolerance Trait in Bahia (\u3cem\u3ePaspalum Notatum\u3c/em\u3e Flugge) Grass Lines

Controlled freeze (-60o C) trials of 31 bahiagrass selections from a breeding program for cold tolerance by Blount et al. (2001) showed diverse genotype Leaf Tissue Cold Damage (LTCD). Breman et al. (2003) defined LTCD on a rating scale (1 = no damage to 9 = 100% leaf damage). Unique midrib damage was observed as part of LTCD in bahiagrass under transpiration stress after a freeze trial. Small xylem conduit diameter and area has been strongly correlated with reduced cavitation caused by freeze thaw cycles which maintain leaf tissue in evergreen temperate woody plants; further shown in twelve woody species by Davis et al. (1999). Air bubbles in vessel ice columns prevent normal refill and function upon thawing. The purpose of this study was to test whether genotype xylem diameter and area could be used to predict LTCD

Indigenous and Non-Indigenous Paraprofessionals: An Empirical Comparison

This paper provides a comparative description of indigenous and nonindigenous paraprofessionals who were employed in a social service capacity in a large urban setting. Personal interviews were conducted with 88 paraprofessionals employed by the Fulton County Department of Family and Children Servives (Atlanta, Ga.). The primary variables discussed include an assessment of the respondent\u27s background, their present employment situation, experience with and attitudes toward welfare and general attitudinal measures. The results provide a basic demographic profile of the indigenous and non-indigenous paraprofessional and indicate their differing characteristics. Briefly, the indigenous respondents were less anomic, felt more efficacious in terms of helping clients, had a less favorable stance toward welfare, had less training and were considerably more more satisfied with their job than were their non-indigenous counterparts. Additionally, the implications of these findings and considerations which need to be explored in future research are discussed

Carbon dioxide capture from a cement manufacturing process

A process of manufacturing cement clinker is provided in which a clean supply of CO.sub.2 gas may be captured. The process also involves using an open loop conversion of CaO/MgO from a calciner to capture CO.sub.2 from combustion flue gases thereby forming CaCO.sub.3/CaMg(CO.sub.3).sub.2. The CaCO.sub.3/CaMg(CO.sub.3).sub.2 is then returned to the calciner where CO.sub.2 gas is evolved. The evolved CO.sub.2 gas, along with other evolved CO.sub.2 gases from the calciner are removed from the calciner. The reactants (CaO/MgO) are feed to a high temperature calciner for control of the clinker production composition