Habitat Conservation Plans under the Endangered Species Act

This Comment analyzes the development of Habitat Conservation Plans (HCP) as a means for planners to free themselves from the prohibitions against the taking of endangered species under the Endangered Species Act. The author argues that the use of the HCP has resulted in an increase in the number of parties seeking statutory permission to take endangered species. The author examines the statutory requirements for the development and approval of HCPs under section 10(a) of the Endangered Species Act. The author further critiques the first three HCPs that were developed, and suggests various changes to harmonize section 10(a) with the rest of the Endangered Species Act

Computer simulation of confined liquid crystal dynamics.

Results are presented from a series of simulations undertaken to determine whether dynamic processes observed in device-scale liquid crystal cells confined between aligning substrates can be simulated in a molecular system using parallel molecular dynamics of the Gay-Berne model.In a nematic cell, on removal of an aligning field, initial near-surface director relaxation can induce flow, termed 'backflow', in the liquid. This, in turn, can cause director rotation, termed 'orientational kickback', in the centre of the cell. Simulations are performed of the relaxation in nematic systems confined between substrates with a common alignment on removal of an aligning field. Results show that relaxation timescales of medium sized systems are accessible. Following this, simulations are performed of relaxation in hybrid aligned nematic systems, where each surface induces a different alignment. Flow patterns associated with director reorientation are observed. The damped oscillatory nature of the relaxation process suggests that the behaviour of these systems is dominated by orientational elastic forces and that the observed director motion and flow do not correspond to the macroscopic processes of backflow and kickback. Chevron structures can occur in confined smectic cells which develop two domains of equal and opposite layer tilt on cooling. Layer tilting is thought to be caused by a need to reconcile a mismatch between bulk and surface smectic layer spacing. Here, simulations are performed of the formation of structures in confined smectic systems where layer tilt is induced by an imposed surface pretilt. Results show that bookshelf, chevron and tilted layer structures are observable in a confined Gay-Berne system. The formation and stability of the chevron structure are shown to be influenced by surface slip

Systematic reviews of surgical procedures in children: Quantity, coverage and quality

Aim Systematic reviews have the potential to map those areas where children are under‐represented in surgical research. We aimed to describe and evaluate the quantity, coverage and the quality of conduct and reporting of systematic reviews of surgical procedures in children. Methods We searched four biomedical databases, a systematic review register, reference lists and conducted hand searching to identify relevant reviews. Two reviewers worked independently to critically appraise included studies and abstract data. We assessed reporting quality using the preferred reporting items for systematic reviews and meta‐analysis statement and methodological quality using the Assessment of Multiple SysTemAtic Reviews tool. Results Fifteen systematic reviews were identified, representing 0.01% of all paediatric surgical citations in MEDLINE and E mbase. Thirteen of the reviews were C ochrane reviews, and most reviews (12/15) addressed subspecialty interests such as otorhinolaryngology. The median number of included trials per systematic review was four (interquartile range 1 to 9.5), the median number of primary outcomes was 5.5 (interquartile range 3.5 to 7.5). In general, reporting and methodological quality was good although there were several omissions, particularly around completeness of reporting of statistical methods used, and utilisation of quality assessments in analyses. Outcomes were often not clearly defined and descriptions of procedures lacked sufficient detail to determine the similarities and differences among surgical procedures within the contributing trials. Conclusion Systematic reviews of surgical procedures in children are rarely published. To improve the evidence base and guide research agendas, more systematic reviews should be conducted, using standard guidelines for conduct and reporting

Medical Device Regulation in Australia: Safe and Effective?

Objective: To describe the frequency, characteristics and outcomes of reports of possible harms related to medical devices submitted to the Australian Therapeutic Goods Administration (TGA) using data made publicly available on the TGA website. Design and setting: A retrospective analysis, conducted in January 2012, of data made publicly available on the TGA website from January 2000 to December 2011. Main outcome measures: The number and nature of reports of medical device incidents, recalls and alerts. Results: Up to December 2011, 6812 incidents involving medical devices were reported to the TGA, although there were several periods where data were unavailable. Incidents were reported more frequently in later years, most often by device sponsors, and were often attributed to mechanical problems. 295 deaths and 2357 serious injuries have been related to incidents, with serious injury (597) highest in 2009. Most incidents involving medical devices were not investigated (47.5%), or, after investigation, no further action was taken (25.0%). During the same time period, there were 35 medical device recalls and 34 medical device alerts issued by the TGA, with no consistent increase over time. Conclusions: Despite TGA reform proposals, greater transparency is still needed. Issues that have not been addressed include patchy and conflicting data in the public domain and lack of explanations for the large proportion of uninvestigated reports. To maintain public confidence in the national regulatory system these problems need to be resolved

Capillary-gravity waves: The effect of viscosity on the wave resistance

The effect of viscosity on the wave resistance experienced by a 2d perturbation moving at uniform velocity over the free surface of a fluid is investigated. The analysis is based on Rayleigh's linearized theory of capillary-gravity waves. It is shown in particular that the wave resistance remains bounded as the velocity of the perturbation approches the minimun phase speed, unlike what is predicted by the inviscid theory.Comment: Europhysics Letters, in pres

Bulk Properties of the Oxygen Reduction Catalyst SrCo_(0.9)Nb_(0.1)O_(3-δ)

The perovskite SrCo_(0.9)Nb_(0.1)O_(3−δ) (SCN) has excellent electrochemical activity toward oxygen reduction, and it is also valuable as a possible model material for other state-of-the-art perovskite catalysts based on strontium and cobalt, such as Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3−δ) (BSCF). Here we report thermogravimetric, conductivity, and diffraction measurements from SCN. We find that the thermodynamic stability limits of SCN are slightly more favorable than those reported for BSCF, although both materials exhibit a slow oxidative partial decomposition under likely operating conditions. In SCN, this decomposition is thermodynamically preferred when the average formal oxidation state of cobalt is greater than ∼3.0+, but due to sluggish kinetics, metastable SCN with higher cobalt valence can be observed. The oxygen stoichiometry 3−δ varies from 2.45 to 2.70 under the conditions studied, 500–1000 °C and 10^(–4)–1 bar O_2, which encompass both stable and metastable behavior. The electronic conductivity is p-type and thermally activated, with a value at 600 °C in air of 250 S cm^(–1), comparable to that of La_(0.8)Sr_(0.2)MnO_(3−δ). The polaron migration enthalpy decreases linearly from 0.30 to 0.05 eV as 3−δ increases from 2.52 to 2.64. Thermal and chemical expansivities are also reported

Bacterial Antigen Expression Is an Important Component in Inducing an Immune Response to Orally Administered Salmonella-Delivered DNA Vaccines

BACKGROUND: The use of Salmonella to deliver heterologous antigens from DNA vaccines is a well-accepted extension of the success of oral Salmonella vaccines in animal models. Attenuated S. typhimurium and S. typhi strains are safe and efficacious, and their use to deliver DNA vaccines combines the advantages of both vaccine approaches, while complementing the limitations of each technology. An important aspect of the basic biology of the Salmonella/DNA vaccine platform is the relative contributions of prokaryotic and eukaryotic expression in production of the vaccine antigen. Gene expression in DNA vaccines is commonly under the control of the eukaryotic cytomegalovirus (CMV) promoter. The aim of this study was to identify and disable putative bacterial promoters within the CMV promoter and evaluate the immunogenicity of the resulting DNA vaccine delivered orally by S. typhimurium. METHODOLOGY/PRINCIPAL FINDINGS: The results reported here clearly demonstrate the presence of bacterial promoters within the CMV promoter. These promoters have homology to the bacterial consensus sequence and functional activity. To disable prokaryotic expression from the CMV promoter a series of genetic manipulations were performed to remove the two major bacterial promoters and add a bacteria transcription terminator downstream of the CMV promoter. S. typhimurium was used to immunise BALB/c mice orally with a DNA vaccine encoding the C-fragment of tetanus toxin (TT) under control of the original or the modified CMV promoter. Although both promoters functioned equally well in eukaryotic cells, as indicated by equivalent immune responses following intramuscular delivery, only the original CMV promoter was able to induce an anti-TT specific response following oral delivery by S. typhimurium. CONCLUSIONS: These findings suggest that prokaryotic expression of the antigen and co-delivery of this protein by Salmonella are at least partially responsible for the successful oral delivery of C-fragment DNA vaccines containing the CMV promoter by S. typhimurium

The effect of oil sands process-affected water and model naphthenic acids on photosynthesis and growth in Emiliania huxleyi and Chlorella vulgaris

Naphthenic acids (NAs) are among the most toxic organic pollutants present in oil sands process waters (OSPW) and enter marine and freshwater environments through natural and anthropogenic sources. We investigated the effects of the acid extractable organic (AEO) fraction of OSPW and individual surrogate NAs, on maximum photosynthetic efficiency of photosystem II (PSII) (FV/FM) and cell growth in Emiliania huxleyi and Chlorella vulgaris as representative marine and freshwater phytoplankton. Whilst FV/FM in E. huxleyi and C. vulgaris was not inhibited by AEO, exposure to two surrogate NAs: (4'-n-butylphenyl)-4-butanoic acid (n-BPBA) and (4'-tert-butylphenyl)-4-butanoic acid (tert-BPBA), caused complete inhibition of FV/FM in E. huxleyi (≥10 mg L-1 n-BPBA; ≥50 mg L-1 tert-BPBA) but not in C. vulgaris. Growth rates and cell abundances in E. huxleyi were also reduced when exposed to ≥10 mg L-1 n- and tert-BPBA; however, higher concentrations of n- and tert-BPBA (100 mg L-1) were required to reduce cell growth in C. vulgaris. AEO at ≥10 mg L-1 stimulated E. huxleyi growth rate (p ≤ 0.002), yet had no apparent effect on C. vulgaris. In conclusion, E. huxleyi was generally more sensitive to NAs than C. vulgaris. This report provides a better understanding of the physiological responses of phytoplankton to NAs which will enable improved monitoring of NA pollution in aquatic ecosystems in the future