Collective enhancement and suppression in Bose-Einstein condensates

The coherent and collective nature of Bose-Einstein condensate can enhance or suppress physical processes. Bosonic stimulation enhances scattering in already occupied states which leads to atom amplification, and the suppression of dissipation leads to superfluidity. In this paper, we review several experiments where suppression and enhancement have been observed and discuss the common roots of and differences between these phenomena.Comment: ICAP proceedings; 12 figure

Epigenetics and the exposomes: Obesity and beyond

The specific genetic alterations that result in diseases and complex syndromes have been and continue to be identified. Search for the origins of disease have led to investigations into the roles of dietary and environmental factors as potential triggers or modifiers of risk. Genome-wide association studies have identified concepts such as the rare variant-common disease hypothesis and the common variant-common disease hypothesis. Through association studies, unique gene-environment interactions, which may occur with or without specific periods of permissiveness or vulnerabilities, have also been identified. Major conditions where the role of exposomes and epigenetics are rapidly evolving are obesity, neurological disorders, immune disorders and cancers. These concepts are particularly intriguing in the context of obesity

Impact of Job Complexity and Performance on CFO Compensation

Prior research suggests that Big 4 auditors provide higher quality audits by virtue of their large size. Still, the recent reforms mandated by the Sarbanes Oxley Act – by increasing client and auditor incentives for accurate reporting – may have narrowed audit quality differences across auditor groups. In this paper, we examine audit quality for Big 4 and Mid-tier auditors during 2003-06 and include clients of other smaller audit firms for comparison purposes. We examine actual audit quality (as proxied by earnings management metrics) as well as perceived audit quality (as proxied by the client- and year-specific eloading and ex ante equity risk premium metrics). We include in our analysis only those Big 4 clients for whom the Mid-tier firms are potentially viable as auditors. Relative to other smaller audit firm clients, we find Big 4 and Mid-tier audit clients to have (1) lower levels of accrual management, (2) higher levels of real earnings management, and (3) higher levels of investor-perceived accruals quality. In each case, we were unable to reject the null that Big 4 and Mid-tier audits are similar. However, we find Big 4 audit clients to have a lower client-specific ex ante equity risk premium relative to both Mid-tier and other smaller audit firm clients. Collectively, our findings indicate that in situations where a Mid-tier auditor is potentially viable, Big 4 clients could utilize a Mid-tier firm without adversely affecting audit quality. Still, the results suggest that Big 4 clients have a lower ex ante cost of equity capital which is likely related to the insurance considerations (“deep pockets”) – rather than the audit quality -- associated with having a Big 4 auditor.Auditor concentration, Audit quality, Earnings management, Cost of equity capital.

Continuous vortex pumping into a spinor condensate with magnetic fields

We study the mechanisms and the limits of pumping vorticity into a spinor condensate through manipulations of magnetic (B-) fields. We discover a fundamental connection between the geometrical properties of the magnetic fields and the quantized circulation of magnetically trapped atoms, a result which generalizes several recent experimental and theoretical studies. The optimal procedures are devised that are capable of continuously increasing or decreasing a condensate's vorticity by repeating certain two step B-field manipulation protocols. We carry out detailed numerical simulations that support the claim that our protocols are highly efficient, stable, and robust against small imperfections of all types. Our protocols can be implemented experimentally within current technologies.Comment: 9 pages, 6 figure

Litigation Risk and Abnormal Accruals

In this paper, we examine the relation between auditor litigation risk and abnormal accruals over the 1989-2007 time period. We address potential endogeneity in prior studies by jointly modeling abnormal accruals and litigation risk in a simultaneous equation system. Our findings suggest that client-specific litigation risk affects auditor incentives to acquiesce to client demands for earnings management, i.e., the higher the risk of auditor litigation, the greater the auditor’s restraining influence on the abnormal accruals reported by the client. We also find evidence that abnormal accruals increase the likelihood of auditor litigation. We also document that the 1995 Public Securities Litigation Reform Act (PSLRA) lowered the client-specific risk of auditor litigation. Litigation reform remains a topic of ongoing interest. Our findings contribute to a better understanding of the effects of litigation reform (and related changes in legal exposure) on auditor incentives and earnings management.: Litigation risk, abnormal accruals, auditor incentives

An evaluation of orbital exenteration at st John eye hospital

A dissertation submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of Master of Medicine in OphthalmologyOrbital exenteration is a surgical procedure used in the management of advanced malignant disease. It is used to treat both invasive and recurrent orbital tumours. This disfiguring surgical procedure involves removal of orbital contents, including the periorbita, eyelids and sometimes varying amounts of the surrounding peri-orbital skin. Studies from developing countries have shown that Squamous Cell Carcinoma (SCC) is the predominant indication for orbital exenteration. The high prevalence of conjunctival SCC in Sub-Saharan African has a strong link to ultraviolet radiation, Human Immunodeficiency Virus infection (HIV) and Human Papilloma Virus (HPV) infection. As the burden of disease increases, it becomes crucial for clinicians in Africa and other developing countries to understand how these Tumours’ behave, and how HIV potentially impacts on the disease. Such an evaluation may potentially benefit current management strategies. Furthermore, the need to effectively and appropriately manage such a neoplastic burden in a developing world setting with limited resources is of fundamental importance. This study reports an experience of orbital exenteration at this institution. OBJECTIVES: Firstly to describe all orbital tumours exenterated at St. John Eye Hospital over a four year period in terms of histopathology, tumour behaviour and completeness of excision. Secondly to determine if a link to HIV infection exists. DESIGN AND METHOD: A retrospective analysis of electronic records from the National Health Laboratory System (NHLS) was conducted on all the patients who underwent an orbital exenteration at St. John Eye Hospital from the 1st of July 2008 to 30th of June 2012 RESULTS: The total number of patients who underwent an orbital exenteration in the stated time period was 84. Twenty eight patients were excluded from the study and the final sample size was therefore 56. The average age of presentation was 42 and the overall female to male ratio was 1:1.07. Four patients underwent a lid sparing procedure while the remaining 52 patients had a total exenteration. The tissue of origin was conjunctival in 75% of cases. The most frequent presenting complaint and indication for surgery was an invasive conjunctival tumour in 56% of patients, followed by a gross orbital tumour in 27% of patients. Squamous cell carcinoma of the conjunctiva was the most frequently diagnosed tumour. Out of 56 specimens, 51(91.06%) were of the squamous cell type, 1.79% High Grade Squamous Dysplasia, 3.57% Leiomyosarcoma, 1.79% Metastatic Breast Adenocarcinoma and 1.79% Spindle Cell Melanoma. Histological grading of all specimens showed 69.64% of these tumours were moderately differentiated, 21.43% poorly differentiated and 8.93% were unknown. The distribution of the tumour staging in the sample group, according to the TNM Classification was as follows, 51.79%- Stage 4, 19.64% -Stage 3, 10.71%-Stage 2, 1.79% Stage 1, 1.79% Stage Tumour In Situ and 14.28% unknown. Regarding completeness of excision, 53.57% of tumours had positive tumour margins and 42.86% showed complete excision with clear margins, 3.57% were unknown. Only 28(50%) patients had a HIV result on electronic record. CD4 counts were available for 23 out of the 28 patients.MT201

Non-invasive genetic monitoring for the threatened valley elderberry longhorn beetle.

The valley elderberry longhorn beetle (VELB), Desmocerus californicus dimorphus (Coleoptera: Cerambycidae), is a federally threatened subspecies endemic to the Central Valley of California. The VELB range partially overlaps with that of its morphologically similar sister taxon, the California elderberry longhorn beetle (CELB), Desmocerus californicus californicus (Coleoptera: Cerambycidae). Current surveying methods are limited to visual identification of larval exit holes in the VELB/CELB host plant, elderberry (Sambucus spp.), into which larvae bore and excavate feeding galleries. Unbiased genetic approaches could provide a much-needed complementary approach that has more precision than relying on visual inspection of exit holes. In this study we developed a DNA sequencing-based method for indirect detection of VELB/CELB from frass (insect fecal matter), which can be easily and non-invasively collected from exit holes. Frass samples were collected from 37 locations and the 12S and 16S mitochondrial genes were partially sequenced using nested PCR amplification. Three frass-derived sequences showed 100% sequence identity to VELB/CELB barcode references from museum specimens sequenced for this study. Database queries of frass-derived sequences also revealed high similarity to common occupants of old VELB feeding galleries, including earwigs, flies, and other beetles. Overall, this non-invasive approach is a first step towards a genetic assay that could augment existing VELB monitoring and accurately discriminate between VELB, CELB, and other insects. Furthermore, a phylogenetic analysis of 12S and 16S data from museum specimens revealed evidence for the existence of a previously unrecognized, genetically distinct CELB subpopulation in southern California