POPULATION GENETICS AND MALE SOCIAL BEHAVIOR IN THE AUSTRALIAN SMALL CARPENTER BEE, CERATINA AUSTRALENSIS

Small carpenter bees (Xylocopinae: Ceratinini) in the genus Ceratina are a cosmopolitan group of stem nesting bees. All Ceratina show a degree of mutual tolerance for nestmates as they nest together in pre-dispersal assemblages and display extended maternal care. Many Ceratina also nest facultatively with multiple females per nest. Males usually disperse before the beginning of the reproductive season. Ceratina have emerged as model organisms to study the evolution of social behavior within the Hymenoptera (ants, bees and wasps). As hymenopteran sex is determined by the haplodiploid sex determination system wherein males are haploid and females are diploid, the result is a relatedness asymmetry between brothers and sisters, whereby sisters share a greater proportion of similar genes compared to brothers. Kin selection theory predicts that daughters are more likely to help rear sisters compared to brothers and is used to explain the prevalence of social behavior within the Hymenoptera. Here the relatedness between populations and within nests of the Australian small carpenter bee Ceratina (neoceratina) australensis is examined with the use 8 polymorphic microsatellite loci. In chapter 1, the eight microsatellite loci are described and applied to three known populations of Ceratina australensis within Australia. Chapter 1 provides evidence for migration from north to south following the river systems of the Murray-Darling River Basin (MRDB). The MRDB has undergone substantial anthropogenic alterations to the natural vegetation communities since European settlement. Chapter 1 provides evidence for the hypothesis that C. australensis expansion into Australia has been aided by the introduction of pithy stemmed plants and establishes how patterns of dispersal can affect the social biology of this species. Chapter 2 deals directly with understanding the presence of male bees within nests of C. australensis that were found predominately, but not exclusively, within the most genetically homogenous population from chapter 1. The existence of inbreeding was not confirmed by visual inspection of genotypes or relatedness estimates between male adults and female offspring. Nests with males had lower brood survivorship compared to solitary nests but reproductive females in nests with males did not have significantly lower fitness compared to reproductive females in other nest types. The inclusive fitness of non-reproductive females was significantly lower than the fitness of reproductive females and the inclusive fitness of males was zero. I speculate that males were potentially delaying reproduction though it is odd that males were not forcefully removed by females. These findings underscore the importance of factors related to the timing of dispersal within the study of social insects

Investigation of frequency-response characteristics of engine speed for a typical turbine-propeller engine

Experimental frequency-response characteristics of engine speed for a typical turbine-propeller engine are presented. These data were obtained by subjecting the engine to sinusoidal variations of fuel flow and propeller-blade-angle inputs. Correlation is made between these experimental data and analytical frequency-response characteristics obtained from a linear differential equation derived from steady-state torque-speed relations

Charged Cylindrical Collapse of Anisotropic Fluid

Following the scheme developed by Misner and Sharp, we discuss the dynamics of gravitational collapse. For this purpose, an interior cylindrically symmetric spacetime is matched to an exterior charged static cylindrically symmetric spacetime using the Darmois matching conditions. Dynamical equations are obtained with matter dissipating in the form of shear viscosity. The effect of charge and dissipative quantities over the cylindrical collapse are studied. Finally, we show that homogeneity in energy density and conformal flatness of spacetime are necessary and sufficient for each other.Comment: 19 pages, accepted for publication in Gen. Relativ. Gra

Investigation of dynamic characteristics of a turbine-propeller engine

Time constants that characterize engine speed response of a turbine-propeller engine over the cruising speed range for various values of constant fuel flow and constant blade angle were obtained both from steady-state characteristics and from transient operation. Magnitude of speed response to changes in fuel flow and blade angle was investigated and is presented in the form of gain factors. Results indicate that at any given value of speed in the engine cruising speed range, time constants obtained both from steady-state characteristics and from transient operation agree satisfactorily for any given constant fuel flow, whereas time constants obtained from transient operation exceed time constants obtained from steady-state characteristics by approximately 14 percent for any given blade angle

Investigation of acceleration characteristics of a single-spool turbojet engine

Operation of a single-spool turbojet engine with constant exhaust-nozzle area was investigated at one flight condition. Data were obtained by subjecting the engine to approximate-step changes in fuel flow, and the information necessary to show the relations of acceleration to the sensed engine variables was obtained. These data show that maximum acceleration occurred prior to stall and surge. In the low end of the engine-speed range the margin was appreciable; in the high-speed end the margin was smaller but had not been completely defined by these data. Data involving acceleration as a function of speed, fuel flow, turbine-discharge temperature, compressor-discharge pressure, and thrust have been presented and an effort has been made to show how a basic control system could be improved by addition of an override in which the acceleration characteristic is used not only to prevent the engine from entering the surge region but also to obtain acceleration along the maximum acceleration line during throttle bursts

Microfiltration in oceanographic research II. Retention of colloidal micelles by adsorptive filters and by filter-feeding invertebrates; proportions of dispersed organic to dispersed inorganic matter and to organic solutes

To adsorb and retain quantitatively the minute colloidal micelles held in dilute suspensions, fine inert inorganic powders (such as MgO and refined diatomaceous earth) or finely porous cellulose membranes may be employed. Minute micelles, such as molecular hemoglobin, are retained also by setous or ciliary-mucous filterfeeders...

Diffusing wild type and sterile mosquitoes in an optimal control setting

This paper develops an optimal control framework to investigate the introduction of sterile type mosquitoes to reduce the overal moquito population. As is well known, mosquitoes are vectors of disease. For instance the WHO lists, among other diseases, Malaria, Dengue Fever, Rift Valley Fever, Yellow Fever, Chikungunya Fever and Zika. [http://www.who.int/mediacentre/factsheets/fs387/en/ ] The goal is to establish the existence of a solution given an optimal sterilization protocol as well as to develop the corresponding optimal control representation to minimize the infiltrating mosquito population while minimizing fecundity and the number of sterile type mosquitoes introduced into the environment per unit time. This paper incorporates the diffusion of the mosquitoes into the controlled model and presents a number of numerical simulations

Cool White Dwarfs Revisited -- New Spectroscopy and Photometry

In this paper we present new and improved data on 38 cool white dwarfs identified by Oppenheimer et al. 2001 (OHDHS) as candidate dark halo objects. Using the high-res spectra obtained with LRIS, we measure radial velocities for 13 WDs that show an H alpha line. We show that the knowledge of RVs decreases the UV-plane velocities by only 6%. The radial velocity sample has a W-velocity dispersion of sig_W = 59 km/s--in between the values associated with the thick disk and the stellar halo. We also see indications for the presence of two populations by analyzing the velocities in the UV plane. In addition, we present CCD photometry for half of the sample, and with it recalibrate the photographic photometry of the remaining WDs. Using the new photometry in standard bands, and by applying the appropriate color-magnitude relations for H and He atmospheres, we obtain new distance estimates. New distances of the WDs that were not originally selected as halo candidates yield 13 new candidates. On average, new distances produce velocities in the UV plane that are larger by 10%, with already fast objects gaining more. Using the new data, while applying the same UV-velocity cut (94 km/s) as in OHDHS, we find a density of cool WDs of 1.7e-4 pc^-3, confirming the value of OHDHS. In addition, we derive the density as a function of the UV-velocity cutoff. The density (corrected for losses due to higher UV cuts) starts to flatten out at 150 km/s (0.4e-4 pc^-3), and is minimized (thus minimizing a possible non-halo contamination) at 190 km/s (0.3e-4 pc^-3). These densities are in a rough agreement with the estimates for the stellar halo WDs, corresponding to a factor of 1.9 and 1.4 higher values.Comment: Accepted to ApJ. New version contains some additional data. Results unchange

Measuring volunteerability and the capacity to volunteer among non-volunteers: implications for social policy

As volunteering and its benefits gain global recognition, social policymakers can sustain and increase volunteering through social policy, legislation and other types of involvement. A key performance practice is to measure the rate of volunteering based on the percentage of the population that volunteer or the number of hours donated. The focus of this article, however, is on the capacity to volunteer by non‐volunteers as well as by volunteers. The concept and theory of volunteerability (an individual's ability to overcome related obstacles and volunteer, based on his or her willingness, capability and availability) offers a richer understanding of how people can be assisted to overcome barriers to maximize their volunteer potential and thus increase volunteering. The article details the definitions and benefits of volunteering and covers examples of related social policy, as well as explaining the concept of volunteerability and how it can be measured using existing and new scales. Based on a mixed methods study in Australia, the article offers specific measures to examine the concept of volunteerability and reveals important differences between volunteers and non‐volunteers. The article also details major barriers to volunteering and how social policies can be developed to overcome them