Reproduction is associated with a tissue-dependent reduction of oxidative stress in eusocial female Damaraland mole-rats (Fukomys damarensis).

This is the final version of the article. Available from Public Library of Science via the DOI in this record.Oxidative stress has been implicated as both a physiological cost of reproduction and a driving force on an animal's lifespan. Since increased reproductive effort is generally linked with a reduction in survival, it has been proposed that oxidative stress may influence this relationship. Support for this hypothesis is inconsistent, but this may, in part, be due to the type of tissues that have been analyzed. In Damaraland mole-rats the sole reproducing female in the colony is also the longest lived. Therefore, if oxidative stress does impact the trade-off between reproduction and survival in general, this species may possess some form of enhanced defense. We assessed this relationship by comparing markers of oxidative damage (malondialdehyde, MDA; protein carbonyls, PC) and antioxidants (total antioxidant capacity, TAC; superoxide dismutase, SOD) in various tissues including plasma, erythrocytes, heart, liver, kidney and skeletal muscle between wild-caught reproductive and non-reproductive female Damaraland mole-rats. Reproductive females exhibited significantly lower levels of PC across all tissues, and lower levels of MDA in heart, kidney and liver relative to non-reproductive females. Levels of TAC and SOD did not differ significantly according to reproductive state. The reduction in oxidative damage in breeding females may be attributable to the unusual social structure of this species, as similar relationships have been observed between reproductive and non-reproductive eusocial insects.This research was supported by a DST-NRF SARChI research chair for Behavioural Ecology and Physiology to NCB and a University of Pretoria postdoctoral fellowship to CMS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

Digging for answers: contributions of density- and frequency-dependent factors on ectoparasite burden in a social mammal

Due to the density-dependent nature of parasite transmission parasites are generally assumed to constrain the evolution of sociality. However, evidence for a correlation between group size and parasite burden is equivocal, particularly for mammals. Host contact rates may be modified by mobility of the host and parasite as well as social barriers. In the current study, we used the common mole-rat (Cryptomys hottentotus hottentotus), a social subterranean rodent, as a model system to investigate the effect of host density and frequency of contact rates on ectoparasite burdens. To address these factors we used a study species that naturally varies in population densities and intergroup contact rates across its geographic range. We found that ectoparasite prevalence, abundance and species richness decreased with increasing host density at a regional scale. At the same time, measures of parasite burden increased with intergroup contact rates. Ectoparasite burdens decreased with colony size at the group level possibly as a result of increased grooming rates. Equating group size with population density might be too simplistic an approach when assessing parasite distributions in social mammals. Our data suggest that frequency-dependent mechanisms may play a much greater role at a population level than density-dependent mechanisms in determining parasite distributions in social species. We suggest that future studies should explicitly consider behavioural mechanisms that may affect parasite distributionNational Research Foundation (South Africa

The Freshman Academy Impact: A Comparison of Ninth Grade Structures Through Analyses of Student Perceptions and Performance Data

A student’s transition from middle school to high school can prove to be a difficult time, often leading to an academic decline, an increase in the number of accumulated discipline referrals, and an increase in absences. In order to help students make the transition, many school systems are establishing freshman academies on their high school campuses to serve as a metaphorical bridge between the middle school and high school. Clark County Schools employs the academy model. This study provides a holistic comparison between Clark County and Lewis County Schools (both pseudonyms), which does not use the ninth grade academy intervention strategy. In order to compare structures, student performance data was gathered in the form of English I End of Course test growth, absences, and discipline referrals. A survey collected student perceptual data with regard to achievement, attendance, and discipline. T-tests were used to determine if a significant difference existed in students’ performance and perceptions depending on their ninth grade structure. The student used student engagement as a framework as it is a strong predictor of academic outcomes such as test scores, grades, attendance, and graduation within the school environment

Factors That Affect The Faith Identity Development Of Evangelical Christian College Students

There is a decided lack of research regarding the faith identity development of evangelical Christian college students within the secular, four-year, public institution. Knowledge of significant events that influence faith identity development is critical to direct practice within the field of student development. In the fall of 2003, 10 college seniors participated in open-ended interviews. This qualitative study identifies key areas of the challenge and support of student' s evangelical Christian faith identitydevelopment. Various subcategories emerged within the broader areas of challenge and support as experienced by evangelical Christian students at one southeastern, comprehensive, public institution. Careful examination and interpretation of the interview responses revealed the liberal atmosphere, exposure to new and diverse ways of thinking, and peer relationships as some of the most salient issues affecting evangelical Christian faith identity development. The findings of this study generate practical applications for practitioners and a number of implications for future research

A feasibility study of two alternate proton radiation compensator designs for use in proton radiation therapy

The purpose of the current thesis was to conduct a feasibility study of alternate methods for creating proton range compensators. Currently, proton range compensators are made of solid materials, but an interest in creating a proton range compensator using fluid has arose in respect to a need for cost and time efficiency. The current process of making proton compensators is costly and time consuming. A fluid-based design is expected to allow doctors to quickly “dial up” a dose within a matter of minutes. The current study included the fabrication, and testing, of a fluid-based range compensator. The fluid-based design consisted of a block of acrylic with an array of holes. Each of the holes was plugged with an acrylic plunger. The plungers were depressed to a desired depth to achieve a specific dosimetric value. The testing sequence used in the current study included multiple compensator configurations that were used to compare the fluid-based design to the conventional solid design. Photon radiation was passed through each compensator and each compensator’s exposure image was compared. The results of the statistical analysis showed no significant similarities between the conventional compensator design and the fluid-based compensator design. Reflection of the current study discusses the potential for the fluid-based design to be used as an alternative method to achieve proton range compensation rather than a replacement for the conventional solid design

Genetic and phenotypic variation among fox squirrels in eastern North Carolina

The longleaf pine (Pinus palustris Mill) ecosystem serves as habitat for the eastern fox squirrel (Sciurus niger L) in the southeastern United States and has been reduced in size and fragmented. Fragmentation often leads to loss of genetic diversity and an increase in population structure of species. To determine if this is happening in the fox squirrels of North Carolina, five microsatellite loci and phenotypic variation were used to compare geographic variation among fox squirrel populations. Fox squirrels showed a low level of population subdivision indicated by FST values of 0.010 to 0.017. In contrast, FIS values were higher (0.222 to 0.230) indicating that inbreeding could be causing a loss of genetic diversity. Linear regression showed a positive correlation between individual weight and longitude and ANOVA analysis revealed squirrels were significantly heavier and shorter west of 78°W longitude, which runs just east of Wilmington N.C. North Carolina fox squirrels were found to be less heterozygous than those of the Midwestern United States, and one locus (FO-41) showed a major decrease in heterozygosity since 1983. Future management of fox squirrels should focus on maintaining habitat and population numbers sufficient to avoid inbreeding. Introducing individuals from other areas may help to increase overall genetic diversity which should also conserve the overall fitness of North Carolina's fox squirrels as it has with other species

A Glimmer of Light in the Great Depression: Women's Agency at the Southern Highlands Craft Guild in the 1930s and 1940s

During the Great Depression southern women’s economic opportunities were mainly limited to farm work or mill labor, with little to no economic equality or security. The Southern Highland Craft Guild of the Appalachian region was a unique entity made up of individual craft producing centers that hired women equally alongside men. Interest in this area stems from the overlooking of the guild in the southern economic narrative. By examining individual accounts of women working within the guild, this paper explores the experiences of rural women who were able to use this organization to achieve independence through craftwork and contributed to a widespread cultural movement throughout Appalachia

The Distribution of Gastrointestinal Parasites in Two Populations of Common Mole-Rats (Cryptomys hottentotus hottentotus)

The spread of parasites through a host population is based on the variation in behavior and immune function between individuals and is rarely uniform. We studied the gastrointestinal parasites of common mole-rats (Cryptomys hottentotus hottentotus, Lesson 1826) from 2 sites and assessed the levels of infection based on host sex, breeding status, and season. Only nematode species were found: Neoheligmonella sp. and Mammalakis macrospiculum (Ortlepp, 1939) and a single specimen of Trichuris sp., all of which have direct life cycles. Parasite burden and species richness was greater in the mesic habitat. The abundance of Neoheligmonella sp. differed significantly between seasons, and the season of peak abundance differed between sites, perhaps due to differences in host densities between sites. In addition, parasite burden did not differ between the sexes, but breeding animals had higher infections of Neoheligmonella sp. and M. macrospiculum than non-breeding animals. This and previous studies thus suggest that the subterranean environment is beneficial in reducing parasite diversity, although the restrictions on movement may lead to certain individuals suffering higher parasite burdens.The NRF-DST SARChI chair for Mammal Behavioural Ecology and Physiology to N.C.B. and a bursary to E.K.A. from the SARChI chair as well as a University of Pretoria Research Fellowship to H.L.http://digitalcommons.unl.edu/jrnlparasitologyhj2018Mammal Research InstituteZoology and Entomolog

Evidence for contrasting roles for prolactin in eusocial naked mole-rats, Heterocephalus glaber and Damaraland mole-rats, Fukomys damarensis

Elevated prolactin (PRL) has been associated with the expression of social and cooperative behaviours in a number of vertebrate species, as well as suppression of reproduction. As social mole-rats exhibit both of these traits, PRL is a prime candidate in mediating their social phenotype. While naked and Damaraland mole-rats (NMRs and DMRs) have evolved eusociality independently within their family, both species exhibit an extreme skew in lifetime reproductive success, with breeding restricted to a single female and one or two males. Non-breeding NMRs of both sexes are physiologically inhibited from reproducing, while in DMRs only the non-breeding females are physiologically suppressed. Newly emerging work has implicated the dopamine system and PRL as a component in socially induced reproductive suppression and eusociality in NMR, but the DMR remains unstudied in this context. To investigate evolutionary convergence in the role of PRL in shaping African mole-rat eusociality, we determined plasma PRL concentrations in breeders and non-breeders of both sexes, comparing DMRs with NMRs. Among samples from non-breeding NMRs 80% had detectable plasma PRL concentrations. As a benchmark, these often (37%) exceeding those considered clinically hyperprolactinaemic (25 ng ml−1) in humans: mean ± s.e.m.: 34.81 ± 5.87 ngml−1; range 0.00–330.30 ng ml−1. Conversely, 85% of non-breeding DMR samples had undetectable values and none had concentrations above 25 ng ml−1: 0.71 ± 0.38 ng ml−1; 0.00–23.87 ngml−1. Breeders in both species had the expected variance in plasma PRL concentrations as part of normal reproductive function, with lactating queens having significantly higher values. These results suggest that while elevated PRL in non-breeders is implicated in NMR eusociality, this may not be the case in DMRs, and suggests a lack of evolutionary convergence in the proximate control of the social phenotype in these mole-rats.SARCHI Chair to NCB (Grant N64756)http://rsbl.royalsocietypublishing2019-05-01hj2018Anatomy and PhysiologyMammal Research InstituteZoology and Entomolog

Remarks tangent to a thesis exhibition of paintings

A dim persistant knowledge of perfected rhythms, of right relations, of suspended and magical unions demands my concern. I do not conceive of art as a counterpart of life, something exchangable for it. It is rather a hopeful activity which our mind originates in order to hold to the possibility of reconciliation with the sensuous world beyond us. It is an intention to subject the immediate and present sensations of our consciousness to the process of a singular formation and capture a personal coherence from the passing moments. My temperament calls for the making of pictures. Desire moves me to search for the secret laws, of nature which are hidden in my spirit and reveal to consciousness correspondences between myself and the rest of the universe