On the existence of infinitely many closed geodesics on orbifolds of revolution

Using the theory of geodesics on surfaces of revolution, we introduce the period function. We use this as our main tool in showing that any two-dimensional orbifold of revolution homeomorphic to S^2 must contain an infinite number of geometrically distinct closed geodesics. Since any such orbifold of revolution can be regarded as a topological two-sphere with metric singularities, we will have extended Bangert's theorem on the existence of infinitely many closed geodesics on any smooth Riemannian two-sphere. In addition, we give an example of a two-sphere cone-manifold of revolution which possesses a single closed geodesic, thus showing that Bangert's result does not hold in the wider class of closed surfaces with cone manifold structures.Comment: 21 pages, 4 figures; for a PDF version see http://www.calpoly.edu/~jborzell/Publications/publications.htm

Factors Associated with Diabetes Risk in South Texas College Students

International Journal of Exercise Science 7(2) : 110-118, 2014. South Texas has a high prevalence of diabetes and college students may be particularly at risk. While increased BMI, sedentary activity and depression have been associated with diabetes progression in the general population, it has not been established whether these factors contribute to increased diabetes risk in college students. The purpose of this study was to assess diabetes risk and determine whether depressive symptoms or physical activity patterns are associated with increased diabetes risk in college students. Sixty-nine college students were assessed for diabetes risk using the Finnish Diabetes Risk Score (FINDRISC) . Each participant completed the International Physical Activity Questionnaire (IPAQ) which included a sitting subscale, the Zung Self-Rated Depression Scale, and had anthropometric measures taken. Of the participants, 21.7% reported elevated risk (FINDRISC score 7-11), and 4.3% of participants had a moderate-to-high risk of developing diabetes (FINDRISC \u3e12). On average, the sample was overweight (BMI = 26.81±0.75 kg . m-2), and BMI was associated with diabetes risk (r = 0.626, p \u3c 0.001). While diabetes risk was not correlated with IPAQ total physical activity score (r = 0.019, p = 0.874), it was modestly correlated with time spent sitting (r = 0.295, p = 0.015). There was no association between self-reported depressive symptoms and diabetes risk (r =0.078, p = 0.525). Although diabetes risk was not associated with total activity and depressive symptoms, it was associated with time spent sitting and BMI. These results suggest that in this population, sitting less and reducing weight may help lower the risk of developing diabetes

Solid serous microcystic adenoma of the pancreas

BACKGROUND: Cystic neoplasms of the pancreas are less common than solid tumors, and portend a better prognosis. They can be divided into serous and mucinous subtypes, with the former behaving less aggressively and generally considered benign. Of the serous neoplasms, serous microcystic adenoma is the most common. An extremely rare solid variant of serous microcystic adenoma lacking secretory capability has been described. Herein, we present the fourth described case of this solid variant and review the literature. CASE PRESENTATION: We present a case of a 62 year-old man with a history of abdominal pain, who on CT scan was found to have a solid mass at the junction of the head and body of the pancreas. The patient was offered resection for diagnosis and treatment, and subsequently underwent distal pancreatectomy and splenectomy. Based on gross pathology, histology and immunohistochemistry, the mass was determined to be a solid serous microcystic adenoma. CONCLUSION: Solid serous microcystic adenoma shows similar histologic and immunohistologic features to its classic cystic counterpart, but lacks any secretory functionality. It appears to behave in a benign manner, and as such, surgical resection is curative for patients with this tumor. Furthermore, until more cases of solid SMA are identified to further elucidate its natural history and improve the reliability of preoperative diagnosis, surgical resection of this solid pancreatic tumor should be considered standard therapy in order to exclude malignancy

Plant production of a virus-like particle-based vaccine candidate against porcine reproductive and respiratory syndrome

Porcine reproductive and respiratory syndrome (PRRS) is a disease leading to spontaneous abortions and stillbirths in sows and lowered life quality and expectancy in growing pigs. PRRS is prevalent worldwide and has significant economic impacts to swine industries around the globe. Co-expression of the two most abundant proteins in the viral envelope, the matrix protein (M) and glycosylated protein 5 (GP5), can produce a neutralizing immune response for the virus providing a potentially effective subunit vaccine against the disease, but these proteins are difficult to express. The goal of this research was to display antigenic portions of the M and GP5 proteins on the surface of tobacco mosaic virus-like particles. A modified tobacco mosaic virus coat protein (TMVc) was transiently expressed in Nicotiana benthamiana leaves and targeted to three subcellular compartments along the secretory pathway to introduce glycosylation patterns important for M-GP5 epitope immunogenicity. We found that accumulation levels in the apoplast were similar to the ER and the vacuole. Because glycans present on plant apoplastic proteins are closest to those present on PRRSV proteins, a TMVcM-GP5 fusion construct was targeted to the apoplast and accumulated at over 0.5 mg/g of plant fresh weight. TMVc virus-like particles self-assembled in plant cells and surface-displayed the M-GP5 epitope, as visualized by transmission electron microscopy and immunogold localization. These promising findings lay the foundation for immunogenicity and protective-immunity studies in animals to examine the efficacy of this vaccine candidate as a measure to control PRRS

Maternal plasma DHA levels increase prior to 29 days post-LH surge in women undergoing frozen embryo transfer: a prospective, observational study of human pregnancy

Context: Docosahexaenoic acid (DHA) is an important fatty acid required for neurological development but its importance during early fetal neurological organogenesis is unknown. Objective: To assess plasma fatty acid changes in early pregnancy in women undergoing natural cycle-frozen embryo transfer as a means of achieving accurately-timed periconceptual sampling. Design: Women undergoing frozen embryo transfer were recruited and serial fasting blood samples were taken pre-luteinising hormone (LH) surge, and at days 18, 29 and 45 post-LH surge and fatty acids were analysed using gas chromatography. Setting: Assisted Conception Unit, Glasgow Royal Infirmary, Scotland Main outcome measures: Plasma fatty acid concentrations, influence of twin pregnancies on DHA plasma concentration. Results: In pregnant women, there was a rapid, early increase in the maternal rate of change of plasma DHA concentration observed by 29 days post-LH surge (mean±SD, from 0.1±1.3 to 1.6±2.9 nmol DHA per mL plasma per day). This early pressure to increase plasma DHA concentration was further emphasised in twin pregnancies where the increase in DHA concentration over 45 days was two-fold higher than in singleton pregnancies (mean±SD increase, 74±39 nmol/mL versus 36±40 nmol/mL). An index of delta-6 desaturase activity increased 30% and positively correlated with the rate of change of DHA concentration between day 18 and 29-post LH surge (R-squared adjusted = 41%, P=0.0002). DHA was the only fatty acid with a continual accelerated increase in plasma concentration and a positive incremental area under the curve (mean±SD, 632±911 nmol/mL x day) over the first 45 days of gestation. Conclusions: An increase in maternal plasma DHA concentration is initiated in human pregnancy prior to neural tube closure which occurs at 28 days' gestation

Factors Associated with Diabetes Risk in South Texas College Students

South Texas has a high prevalence of diabetes and college students may be particularly at risk for developing diabetes. Early detection and prevention are crucial to reducing the prevalence of this disease. While increased BMI, sedentary activity and depression have been associated with diabetes progression in the general population, it has not been established whether these factors contribute to increased risk for developing diabetes in college students. PURPOSE: To assess diabetes risk and to determine whether depressive symptoms or physical activity patterns are associated with increased diabetes risk in college students. METHODS: 69 college students were assessed for diabetes risk using the Finnish Diabetes Risk Score (FINDRISC) questionnaire. Each subject also completed the International Physical Activity Questionnaire (IPAQ) long form which includes a sitting subscale, the Zung Self-Rated Depression Scale and had anthropometric measures taken. Relationships were determined using Pearson Product Movement correlation, α=0.05. RESULTS: 21.7% of students reported an elevated risk (FINDRISC score 7-11), and 4.3% of subjects had a moderate to high risk of developing diabetes (FINDRISC \u3e12). On average, the sample of students were overweight (BMI = 26.81±0.75 kg . m-2), and BMI was associated with diabetes risk (r = 0.626, p = 0.001). While diabetes risk was not correlated with the IPAQ total physical activity score (r = 0.019, p = 0.874), it had a modest correlation with time spent sitting (r = 0.295, p = 0.015). There was no association between self-reported depressive symptoms and diabetes risk (r =0.078, p = 0.525). CONCLUSION: A substantial number of college students in South Texas are at risk for developing diabetes. Although diabetes risk was not associated with total physical activity and depressive symptoms, it was associated with time spent sitting and BMI. This suggests that in this college-age population, sitting less and reducing weight may help lower the risk of developing diabetes

Comparison of work fluctuation relations

We compare two predictions regarding the microscopic fluctuations of a system that is driven away from equilibrium: one due to Crooks [J. Stat. Phys. 90, 1481 (1998)] which has gained recent attention in the context of nonequilibrium work and fluctuation theorems, and an earlier, analogous result obtained by Bochkov and Kuzovlev [Zh. Eksp. Teor. Fiz. 72(1), 238247 (1977)]. Both results quantify irreversible behavior by comparing probabilities of observing particular microscopic trajectories during thermodynamic processes related by time-reversal, and both are expressed in terms of the work performed when driving the system away from equilibrium. By deriving these two predictions within a single, Hamiltonian framework, we clarify the precise relationship between them, and discuss how the different definitions of work used by the two sets of authors gives rise to different physical interpretations. We then obtain a extended fluctuation relation that contains both the Crooks and the Bochkov-Kuzovlev results as special cases.Comment: 14 pages with 1 figure, accepted for publication in the Journal of Statistical Mechanic

Infrared Emission from the Nearby Cool Core Cluster Abell 2597

We observed the brightest central galaxy (BCG) in the nearby (z=0.0821) cool core galaxy cluster Abell 2597 with the IRAC and MIPS instruments on board the Spitzer Space Telescope. The BCG was clearly detected in all Spitzer bandpasses, including the 70 and 160 micron wavebands. We report aperture photometry of the BCG. The spectral energy distribution exhibits a clear excess in the FIR over a Rayleigh-Jeans stellar tail, indicating a star formation rate of ~4-5 solar masses per year, consistent with the estimates from the UV and its H-alpha luminosity. This large FIR luminosity is consistent with that of a starburst or a Luminous Infrared Galaxy (LIRG), but together with a very massive and old population of stars that dominate the energy output of the galaxy. If the dust is at one temperature, the ratio of 70 to 160 micron fluxes indicate that the dust emitting mid-IR in this source is somewhat hotter than the dust emitting mid-IR in two BCGs at higher-redshift (z~0.2-0.3) and higher FIR luminosities observed earlier by Spitzer, in clusters Abell 1835 and Zwicky 3146.Comment: Accepted at Ap

A Historical Perspective on Presentations of Hypertensive Acute Heart Failure

BACKGROUND: The initial systolic blood pressure (SBP) in patients presenting to the hospital with acute heart failure (AHF) informs prognosis, diagnosis, and guides initial treatment. However, over time AHF presentations with elevated SBP appear to have declined. The present study examined whether the frequency of AHF presentations with systolic hypertension (SBP \u3e 160 mmHg) declined over a nearly two-decade time interval. METHODS: This study compares four historical, cross-sectional cohorts with AHF who were admitted to tertiary care medical centres in the North-eastern USA in 1995, 2000, 2006, and 2011-13. The main outcome was the proportion of AHF patients presenting with an initial SBP \u3e 160 mmHg. RESULTS: 2,366 patients comprised the study sample. The average age was 77 years, 55% were female, 94% white, and 75% had prior heart failure. In 1995, 34% of AHF patients presented with an initial SBP \u3e 160 mmHg compared to 20% in 2011-2013 (p \u3c 0.01). Multivariate logistic regression demonstrated reduced odds of presenting with a SBP \u3e 160 mmHg in 2006 (0.64, 95% CI 0.42-0.96) and 2011-13 (0.46, 95% CI 0.28-0.74) compared with patients in 1995. CONCLUSION: The proportion of patients with AHF and initial SBP \u3e 160 mmHg significantly declined over the study time period. There are several potential reasons for this observation and these findings highlight the need for ongoing surveillance of patients with AHF as changing clinical characteristics can impact early treatment decisions