3,555 research outputs found
Recommended from our members
Assessing Feeding Damage from Two Leaffooted Bugs, Leptoglossus clypealis Heidemann and Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae), on Four Almond Varieties.
Leaffooted bugs (Leptoglossus spp; Hemiptera: Coreidae) are phytophagous insects native to the Western Hemisphere. In California, Leptoglossus clypealis and Leptoglossus zonatus are occasional pests on almonds. Early season feeding by L. clypealis and L. zonatus leads to almond drop, while late season feeding results in strikes on kernels, kernel necrosis, and shriveled kernels. A field cage study was conducted to assess feeding damage associated with L. clypealis and L. zonatus on four almond varieties, Nonpareil, Fritz, Monterey, and Carmel. The objectives were to determine whether leaffooted bugs caused significant almond drop, to pinpoint when the almond was vulnerable, and to determine the final damage at harvest. Branches with ~20 almonds were caged and used to compare almond drop and final damage in four treatments: (1) control branches, (2) mechanically punctured almonds, (3) adult Leptoglossus clypealis, and (4) adult Leptoglossus zonatus. Replicates were set up for eight weeks during two seasons. Early season feeding resulted in higher almond drop than late season, and L. zonatus resulted in greater drop than L. clypealis. The almond hull width of the four varieties in the study did not influence susceptibility to feeding damage. The final damage assessment at harvest found significant levels of kernel strikes, kernel necrosis, and shriveled almonds in bug feeding cages, with higher levels attributed to L. zonatus than L. clypealis. Further research is warranted to develop an Integrated Pest Management program with reduced risk controls for L. zonatus
Does the adoption of IFRS affect corporate social disclosure in annual reports?
In this exploratory study we investigate the impact of the implementation of IFRS on corporate social disclosures (CSD) within the context of stakeholder theory. We measure the level of CSD in annual reports using a disclosure instrument based on the United Nations Conference on Trade and Development report “Guidance on Corporate Responsibility Indicators in Annual Reports”. We find that IFRS adoption had a differential effect on CSD based on a firm\u27s institutional setting i.e., the stakeholder–management relationship prevalent in their institutional environment. Firms in the stakeholder countries did not have a significant change in the level of CSD following the mandatory adoption of IFRS while firms from the shareholder countries experienced a significant increase over the same period resulting in shareholder countries providing an overall higher level of CSD after IFRS adoption than stakeholder countries. These findings suggest that firms\u27 reactions to the requirements of IFRS and the stakeholder pressure to provide additional CSD are influenced by institutional environment. Further, our results provide support for the use of stakeholder theory to predict the level of CSD
Release of Ciprofloxacin-HCl and Dexamethasone Phosphate by Hyaluronic Acid Containing Silicone Polymers
Nguyen, D., Hui, A., Weeks, A., Heynen, M., Joyce, E., Sheardown, H., & Jones, L. (2012). Release of Ciprofloxacin-HCl and Dexamethasone Phosphate by Hyaluronic Acid Containing Silicone Polymers. Materials, 5(12), 684–698. https://doi.org/10.3390/ma5040684The purpose of this study was to determine the effect of the covalent incorporation of hyaluronic acid (HA) into conventional hydrogel and hydrogels containing silicone as models for contact lens materials on the uptake and release of the fluoroquinolone antibiotic ciprofloxacin and the anti-inflammatory steroid dexamethasone phosphate. A 3 mg/mL ciprofloxacin solution (0.3% w/v) and a 1 mg/mL dexamethasone phosphate solution (0.1%) was prepared in borate buffered saline. Three hydrogel material samples (pHEMA; pHEMA TRIS; DMAA TRIS) were prepared with and without the covalent incorporation of HA of molecular weight (MW) 35 or 132 kDa. Hydrogel discs were punched from a sheet of material with a uniform diameter of 5 mm. Uptake kinetics were evaluated at room temperature by soaking the discs for 24 h. Release kinetics were evaluated by placing the drug-loaded discs in saline at 34 °C in a shaking water bath. At various time points over 6–7 days, aliquots of the release medium were assayed for drug amounts. The majority of the materials tested released sufficient drug to be clinically relevant in an ophthalmic application, reaching desired concentrations for antibiotic or anti-inflammatory activity in solution. Overall, the silicone-based hydrogels (pHEMA TRIS and DMAA TRIS), released lower amounts of drug than the conventional pHEMA material (p < 0.001). Materials with HA MW132 released more ciprofloxacin compared to materials with HA MW35 and lenses without HA (p < 0.02). Some HA-based materials were still releasing the drug after 6 days.This study is supported by the Natural Sciences and Engineering Research Council (NSERC) 20/20 Network for the Development of Advanced Ophthalmic Materials. AH is supported by NSERC Canada, the Canadian Optometric Education Trust Fund (COETF), and a Vistakon® Research Grant and Ezell Fellowship, both administered by the American Optometric Foundation (AOF)
Critical temperature of non-interacting Bose gases on disordered lattices
For a non-interacting Bose gas on a lattice we compute the shift of the
critical temperature for condensation when random-bond and onsite disorder are
present. We evidence that the shift depends on the space dimensionality D and
the filling fraction f. For D -> infinity (infinite-range model), using results
from the theory of random matrices, we show that the shift of the critical
temperature is negative, depends on f, and vanishes only for large f. The
connections with analogous results obtained for the spherical model are
discussed. For D=3 we find that, for large f, the critical temperature Tc is
enhanced by disorder and that the relative shift does not sensibly depend on f;
at variance, for small f, Tc decreases in agreement with the results obtained
for a Bose gas in the continuum. We also provide numerical estimates for the
shift of the critical temperature due to disorder induced on a non-interacting
Bose gas by a bichromatic incommensurate potential.Comment: 18 pages, 8 figures; Fig. 8 improved adding results for another value
of q (q=830/1076
Geographic Population Structure of the Sugarcane Borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), in the Southern United States
The sugarcane borer moth, Diatraea saccharalis, is widespread throughout the Western Hemisphere, and is considered an introduced species in the southern United States. Although this moth has a wide distribution and is a pest of many crop plants including sugarcane, corn, sorghum and rice, it is considered one species. The objective was to investigate whether more than one introduction of D. saccharalis had occurred in the southern United States and whether any cryptic species were present. We field collected D. saccharalis in Texas, Louisiana and Florida in the southern United States. Two molecular markers, AFLPs and mitochondrial COI, were used to examine genetic variation among these regional populations and to compare the sequences with those available in GenBank and BOLD. We found geographic population structure in the southern United States which suggests two introductions and the presence of a previously unknown cryptic species. Management of D. saccharalis would likely benefit from further investigation of population genetics throughout the range of this species
Tumor Mutation Burden Forecasts Outcome in Ovarian Cancer with BRCA1 or BRCA2 Mutations
Background: Increased number of single nucleotide substitutions is seen in breast and ovarian cancer genomes carrying disease-associated mutations in BRCA1 or BRCA2. The significance of these genome-wide mutations is unknown. We hypothesize genome-wide mutation burden mirrors deficiencies in DNA repair and is associated with treatment outcome in ovarian cancer. Methods and Results: The total number of synonymous and non-synonymous exome mutations (Nmut), and the presence of germline or somatic mutation in BRCA1 or BRCA2 (mBRCA) were extracted from whole-exome sequences of high-grade serous ovarian cancers from The Cancer Genome Atlas (TCGA). Cox regression and Kaplan-Meier methods were used to correlate Nmut with chemotherapy response and outcome. Higher Nmut correlated with a better response to chemotherapy after surgery. In patients with mBRCA-associated cancer, low Nmut was associated with shorter progression-free survival (PFS) and overall survival (OS), independent of other prognostic factors in multivariate analysis. Patients with mBRCA-associated cancers and a high Nmut had remarkably favorable PFS and OS. The association with survival was similar in cancers with either BRCA1 or BRCA2 mutations. In cancers with wild-type BRCA, tumor Nmut was associated with treatment response in patients with no residual disease after surgery. Conclusions: Tumor Nmut was associated with treatment response and with both PFS and OS in patients with high-grade serous ovarian cancer carrying BRCA1 or BRCA2 mutations. In the TCGA cohort, low Nmut predicted resistance to chemotherapy, and for shorter PFS and OS, while high Nmut forecasts a remarkably favorable outcome in mBRCA-associated ovarian cancer. Our observations suggest that the total mutation burden coupled with BRCA1 or BRCA2 mutations in ovarian cancer is a genomic marker of prognosis and predictor of treatment response. This marker may reflect the degree of deficiency in BRCA-mediated pathways, or the extent of compensation for the deficiency by alternative mechanisms
Building better scientists through cross-disciplinary collaboration in synthetic biology: a meeting report from the genome consortium for active teaching (GCAT) workshop 2010
Building Better Scientists through Cross-Disciplinary Collaboration in Synthetic Biology: A Report from the Genome Consortium for Active Teaching Workshop 2010
A common problem faced by primarily undergraduate institutions is the lack of funding and material support needed to adequately expose students to modern biology, including synthetic biology. To help alleviate this problem, the Genome Consortium for Active Teaching (GCAT) was founded in 2000 by Malcolm Campbell at Davidson College to bring genomics into the undergraduate curriculum. GCAT’s first tangible activity was to serve as a central clearinghouse both for the purchase and reading of DNA microarrays and for information on how to execute genomics experiments at undergraduate institutions. In response to the evolution of molecular biology in the last decade, Campbell, along with Davidson colleague Laurie Heyer and collaborators Todd Eckdahl and Jeff Poet of Missouri Western State University, organized a Howard Hughes Medical Institute (HHMI)-sponsored GCAT workshop at Davidson in July of 2010. This workshop explored how faculty from multiple disciplines could work together to bring synthetic biology to the undergraduate classroom and laboratory
Building Better Scientists through Cross-Disciplinary Collaboration in Synthetic Biology: A Report from the Genome Consortium for Active Teaching Workshop 2010
A common problem faced by primarily undergraduate institutions is the lack of funding and material support needed to adequately expose students to modern biology, including synthetic biology. To help alleviate this problem, the Genome Consortium for Active Teaching (GCAT) was founded in 2000 by Malcolm Campbell at Davidson College to bring genomics into the undergraduate curriculum. GCAT’s first tangible activity was to serve as a central clearinghouse both for the purchase and reading of DNA microarrays and for information on how to execute genomics experiments at undergraduate institutions. In response to the evolution of molecular biology in the last decade, Campbell, along with Davidson colleague Laurie Heyer and collaborators Todd Eckdahl and Jeff Poet of Missouri Western State University, organized a Howard Hughes Medical Institute (HHMI)-sponsored GCAT workshop at Davidson in July of 2010. This workshop explored how faculty from multiple disciplines could work together to bring synthetic biology to the undergraduate classroom and laboratory
- …