RbHe Potential Energy Surface Sensitivity Study

This paper studies how alterations of features of RbHe potential energy surfaces (PES) for a diode pumped alkali laser (DPAL) system effect the collisional cross section. The Split-Operator method is used to propagate a wave function along these PES and because they are radially coupled, the wave function can be transmitted from the starting surface to other energy surfaces. This transmittance is encoded in the correlation function. The full Hamiltonian used for propagation consists of the electronic potential, the nuclear kinetic energy, and the Coriolis coupling. The correlation function is used to generate the Scattering Matrix elements. These elements describe the transmittance and reflectance coefficients of the reactant wave packet. A temperature averaged cross section is then calculate for the π1/2 to π3/2 transition. Despite large changes in the correlation function and S-Matrix elements, the temperature averaged cross section varied little with change in PES and fell within experimental error margins

Expression patterns of chondrocyte genes cloned by differential display in tibial dyschondroplasia

AbstractTibial dyschondroplasia (TD) appears to involve a failure of the growth plate chondrocytes within growing long bones to differentiate fully to the hypertrophic stage, resulting in a mass of prehypertrophic chondrocytes which form the avascular TD lesion. Many biochemical and molecular markers of chondrocyte hypertrophy are absent from the lesion, or show reduced expression, but the cause of the disorder remains to be identified. As differentiation to the hypertrophic state is impaired in TD, we hypothesised that chondrocyte genes that are differentially expressed in the growth plate should show altered expression in TD. Using differential display, four genes, B-cadherin, EF2, HT7 and Ex-FABP were cloned from chondrocytes stimulated to differentiate to the hypertrophic stage in vitro, and their differential expression confirmed in vivo. Using semi-quantitative RT-PCR, the expression patterns of these genes were compared in chondrocytes from normal and TD growth plates. Surprisingly, none of these genes showed the pattern of expression that might be expected in TD lesion chondrocytes, and two of them, B-cadherin and Ex-FABP, were upregulated in the lesion. This indicates that the TD phenotype does not merely reflect the absence of hypertrophic marker genes, but may be influenced by more complex developmental mechanisms/defects than previously thought

Mollusc shell periostracum as an alternative to tissue in isotopic studies

Recent studies have used carbon and nitrogen stable isotope ratios of preserved soft tissues to examine historical changes in trophic patterns of aquatic ecosystems. A limitation in this application is the difficulty in finding specimens for primary consumers, which can act as a surrogate for basal food sources in determining the trophic status of higher consumers. The availability of preserved soft tissues of invertebrate primary consumers is often limited in museum and archival collections; hard parts such as mollusc shells, however, are often abundant because of their ease of storage. We used stable isotope ratios of carbon and nitrogen to determine if there was a relationship between the isotopic composition of the periostracum of the shell and soft body tissue of freshwater molluscs. We found a significant correlation between (1) periostracum and tissue of freshly collected freshwater mussels, (2) ethanol-preserved adductor muscle tissue and dry-preserved mussels from museum collections, and (3) ethanol-preserved tissue and periostracum of gastropods from museum collections. The predictability of these relationships enhances the capacity to track changes in trophic complexity over time and responses of food webs to natural and anthropogenic environmental perturbations

Putting New Life Into Pastures

Many of the old permanent bluegrass pastures in Iowa can almost be made “ to feed two cattle where one fed before.” We found this out from a study of the problem at Mt. Pleasant during the 6 years, 1933 to 1938. In the past 3 years some 250 Iowa farmers in 45 counties have cooperated in demonstrating the possibilities of increasing the returns from permanent pastures by introducing clover into old grass sods and from applying lime and phosphate fertilizer in addition to reseeding

Animal diets in the Waterberg based on stable isotopic composition of faeces

Faecal analysis of diet in free-ranging mammals can provide insight into local habitat conditions by reflecting the resources actually utilized. Here we used stable light isotope analysis of faeces to qualify, as well as quantify, certain aspects of mammal food selection in a recovering, nutrient-poor, savanna habitat in the Waterberg. Stable carbon isotope ratios in faeces reflect proportions of C3-foods (browse) to C4-foods (grass) consumed, whereas stable nitrogen isotope ratios reflect a combination of trophic behaviour, protein intake, and water and nutritional stress. Percentage nitrogen indicates the nutritional quality of the diet, at least in terms of crude protein intake. We used these data to reconstruct and compare the diets of various mammal species from two reserves in the Waterberg: the Welgevonden Private Game Reserve and Zoetfontein Private Game Farm

The ALMaQUEST survey – III. Scatter in the resolved star-forming main sequence is primarily due to variations in star formation efficiency

Using a sample of 11,478 spaxels in 34 galaxies with molecular gas, star formation and stellar maps taken from the ALMA-MaNGA QUEnching and STar formation (ALMaQUEST) survey, we investigate the parameters that correlate with variations in star formation rates on kpc scales. We use a combination of correlation statistics and an artificial neural network to quantify the parameters that drive both the absolute star formation rate surface density (Sigma_SFR), as well as its scatter around the resolved star forming main sequence (Delta Sigma_SFR). We find that Sigma_SFR is primarily regulated by molecular gas surface density (Sigma_H2) with a secondary dependence on stellar mass surface density (Sigma_*), as expected from an `extended Kennicutt-Schmidt relation'. However, Delta Sigma_SFR is driven primarily by changes in star formation efficiency (SFE), with variations in gas fraction playing a secondary role. Taken together, our results demonstrate that whilst the absolute rate of star formation is primarily set by the amount of molecular gas, the variation of star formation rate above and below the resolved star forming main sequence (on kpc scales) is primarily due to changes in SFE

Accuracy of Ultrasonography-Guided Fine-Needle Aspiration in Detecting Persistent Nodal Disease After Chemoradiotherapy

IMPORTANCE: Few patients with persistent adenopathy following chemoradiotherapy (CRT) for head and neck squamous cell carcinoma harbor viable disease. Improved selectivity for surgical salvage is needed to prevent unnecessary salvage neck dissection. OBJECTIVE: To determine whether ultrasonography-guided fine-needle aspiration (FNA) can be used to identify viable cancer cells in the lymph nodes of patients with persistent radiographic adenopathy following CRT. DESIGN, SETTING, AND PARTICIPANTS: A pilot study included patients undergoing preoperative ultrasonography-guided FNA of lymph nodes considered suspicious on radiography prior to planned neck dissection at a quaternary care facility from February 28, 2011, to March 18, 2013. Data analysis was performed from April 28 to December 24, 2013. Patients treated for head and neck squamous cell carcinoma with CRT who were determined to have persistent neck disease on a 6-week posttreatment computed tomographic scan of the neck and scheduled for salvage neck dissection were considered candidates for this pilot study. All patients enrolled in the study underwent ultrasonography-guided FNA of the suspicious lymph nodes within 2 weeks of the planned neck dissection. The cytopathologist reading the samples was blinded to the patient's identity. EXPOSURES: Fine-needle aspiration with a 23- to 25-gauge needle following CRT. MAIN OUTCOMES AND MEASURES: The accuracy of ultrasonography-guided FNA cytologic results was compared with the standard of surgical pathologic examination of neck dissection specimens. RESULTS: Fourteen patients (11 [79%] men; mean [SD] age, 57.8 [11.2] years) were enrolled in this pilot study; data were collected on 17 lymph nodes. Among these 14 patients with incomplete radiographic clinical response, 17 lymph node aspirations were performed. Ultrasonography-guided FNA identified squamous cell carcinoma in the aspirates of 4 (80%) of the 5 nodes with squamous cell carcinoma identified on pathologic testing and confirmed the absence of disease in the remaining 12 (71%) lymph nodes. The statistical analysis of these results revealed a sensitivity of 80%; specificity, 100%; positive predictive value, 100%; and negative predictive value, 92.3%. The diagnostic accuracy of ultrasonography-guided FNA at detecting residual persistent cancer was 88%. CONCLUSIONS AND RELEVANCE: This pilot study suggests that ultrasonography-guided FNA may be a feasible ancillary diagnostic imaging tool to imaging to assess patients with radiographic persistent disease prior to consideration of salvage neck dissection

Institutional management of greenhouse gas emissions: How much does 'green' reputation matter?

Climate Change, green reputation, conjoint analysis, Environmental Economics and Policy, Resource /Energy Economics and Policy, Q29, Q40, Q51,

The decline and conservation of bumblebees

Declines in bumblebee species in the last 60 years are well documented in Europe, where they are primarily driven by habitat loss and declines in floral abundance and diversity resulting from agricultural intensification. Impacts of habitat degradation and fragmentation are likely to be compounded by the social nature of bumblebees and their largely monogamous breeding system which renders their effective population size low. Hence populations are susceptible to stochastic extinction events and inbreeding. In North America, catastrophic declines of some bumblebee species since the 1990s are probably attributable to the accidental introduction of a non-native parasite from Europe, a result of global trade in domesticated bumblebee colonies used for pollination of greenhouse crops. Given the importance of bumblebees as pollinators of crops and wildflowers, it is vital that steps be taken to prevent further declines. Suggested measures include tight regulation of commercial bumblebee use and targeted use of agri-environment schemes to enhance floristic diversity in agricultural landscapes