Females in Control: Female Sensitivity to Predation Risk Affects Courtship and Reproductive Behaviours

Even in the absence of direct killing, predators have a pervasive effect on prey populations through costly anti-predator behavioural responses. In high risk environments, animals can reduce conspicuous behaviours such as courtship displays decreasing exposure at the cost of reproduction. Previous studies typically looked at male behaviour immediately following a predator cue, thus, not considering temporal variations in risk or the impact of female receptivity on male courtship. I placed male and female brown-headed cowbirds under chronically elevated predation risk with periods of high and low risk. Under high predation risk, females performed fewer chatter calls and were more likely to reject courting males. Females also spent less time searching for host nests. Males greatly attenuated courtship displays, but male-male interactions were unaffected. I suggest that females perceive a greater risk associated with these reproductive behaviours and that it is the females that drive the predation risk effects on courtship

Elliptic Genera and 3d Gravity

We describe general constraints on the elliptic genus of a 2d supersymmetric conformal field theory which has a gravity dual with large radius in Planck units. We give examples of theories which do and do not satisfy the bounds we derive, by describing the elliptic genera of symmetric product orbifolds of $K3$, product manifolds, certain simple families of Calabi-Yau hypersurfaces, and symmetric products of the "Monster CFT." We discuss the distinction between theories with supergravity duals and those whose duals have strings at the scale set by the AdS curvature. Under natural assumptions we attempt to quantify the fraction of (2,2) supersymmetric conformal theories which admit a weakly curved gravity description, at large central charge.Comment: 50 pages, 9 figures, v2: minor corrections to section

Development of serial verb constructions in Cantonese- speaking preschool children

"A dissertation submitted in partial fulfilment of the requirements for the Bachelor of Science (Speech and Hearing Sciences), The University of Hong Kong, June 30, 2006."Also available in print.Thesis (B.Sc)--University of Hong Kong, 2006.published_or_final_versionSpeech and Hearing SciencesBachelorBachelor of Science in Speech and Hearing Science

PARPis As Immune Modulating Agents in Preventing Ovarian Cancer Recurrence

https://openworks.mdanderson.org/sumexp22/1144/thumbnail.jp

Age-like Phenotype of Microglia During HIV-1 Infection

HIV Associated Neurocognitive Disorder (HAND) persists in 50% of infected patients despite treatments. Moreover, HAND potentiates aging-associated neurocognitive decline as the infected population grow older. Microglia cells support productive HIV-1 infection in the brain and elevated senescence markers including p53 and p21 have been detected in microglia in HAND tissues. We hypothesize that HIV-1 induces age-like phenotypes in microglia. In an in vitro model of primary human microglia infected with HIV-1 pseudotype, we examined various markers of aging including the expression of cell cycle inhibitors (p53, p21 and p16), DNA damage associated p53 binding protein 1 (53BP1) foci formation, senescence associated [beta]-galactosidase (SA-[beta]-gal) activity, and the development of Senescence Associated Secretory Phenotype (SASP). Finally, we examined mitochondrial reactive oxygen species (ROS) and mitochondrial respiration, which are known to be altered during organismal aging. We detected elevated expression of p53 and p21, increased percentage of cells expressing 53BP1 foci and [beta]-gal, as well as significantly elevated levels of various cytokines including IL8 and IL6 post infection. The development of age-like phenotype is accompanied by increased mitochondrial ROS production and altered mitochondrial respiratory activity. Finally, exposure to the supernatant of infected microglia results in elevated p21 and caveolin-1 protein expression. Overall, we have demonstrated for the first time age-like phenotypes in human microglia during HIV-1 infection. HIV-1 induced microglial age-like phenotype could play a role in the development of HAND.Ph.D., Molecular and Cell Biology and Genetics -- Drexel University, 201

Speleothem record of mild and wet mid-Pleistocene climate in northeast Greenland

The five interglacials before the Mid-Brunhes Event (MBE) [c.430 thousand years (ka) ago] are generally considered to be globally cooler than those post-MBE. Inhomogeneities exist regionally, however, which suggest that the Arctic was warmer than present during Marine Isotope Stage (MIS) 15a. Using the first speleothem record for the High Arctic, we investigate the climatic response of northeast Greenland between c.588 and c.549 ka ago. Our results indicate an enhanced warmth of at least +3.5 degrees C relative to the present, leading to permafrost thaw and increased precipitation. We find that delta O-18 of precipitation was at least 3 parts per thousand higher than today and recognize two local cooling events (c.571 and c.594 ka ago) thought to be caused by freshwater forcing. Our results are important for improving understanding of the regional climatic response leading up to the MBE and specifically provide insights into the climatic response of a warmer Arctic