Stereoisomer libraries: Total synthesis of all 16 stereoisomers of the pine sawfly sex pheromone by a fluorous mixture-synthesis approach

All 16 stereoisomers of the sex pheromone of pine sawfly (3,7,11-trimethylundecanol propanoate ester) have been synthesized on a 10- to 20-mg scale by a split-parallel fluorous mixture-synthesis approach. Spectral data obtained for all 32 compounds (16 alcohols and the corresponding propionates) matched well with published data, thereby validating the fluorous-tag encoding of diastereoisomers. This fluorous-tag encoding method is recommended for the efficient synthesis of multiple stereoisomers for spectroscopic studies, biological tests, or other structure-function relationships

GRB Energetics in the Swift Era

We examine the rest frame energetics of 76 gamma-ray bursts (GRBs) with known redshift that were detected by the Swift spacecraft and monitored by the satellite's X-ray Telescope (XRT). Using the bolometric fluence values estimated in Butler et al. 2007b and the last XRT observation for each event, we set a lower limit the their collimation corrected energy Eg and find that a 68% of our sample are at high enough redshift and/or low enough fluence to accommodate a jet break occurring beyond the last XRT observation and still be consistent with the pre-Swift Eg distribution for long GRBs. We find that relatively few of the X-ray light curves for the remaining events show evidence for late-time decay slopes that are consistent with that expected from post jet break emission. The breaks in the X-ray light curves that do exist tend to be shallower and occur earlier than the breaks previously observed in optical light curves, yielding a Eg distribution that is far lower than the pre-Swift distribution. If these early X-ray breaks are not due to jet effects, then a small but significant fraction of our sample have lower limits to their collimation corrected energy that place them well above the pre-Swift Eg distribution. Either scenario would necessitate a much wider post-Swift Eg distribution for long cosmological GRBs compared to the narrow standard energy deduced from pre-Swift observations. We note that almost all of the pre-Swift Eg estimates come from jet breaks detected in the optical whereas our sample is limited entirely to X-ray wavelengths, furthering the suggestion that the assumed achromaticity of jet breaks may not extend to high energies.Comment: 30 pages, 10 figures, Accepted to Ap

Angiotensin II in the Treatment of Distributive Shock, an Old Theory Revitalized

Objective: To assess whether or not angiotensin II in combination with current treatment has a favorable outcome in the treatment of distributive shock in terms of decreasing duration of vasopressor usage, increasing mean arterial pressure (MAP) above 65 mmHg, and improving mortality. Design: Systematic Literature Review Methods: Searches were conducted in PubMed, Google Scholar, and the James Madison University Library Database for the key terms angiotensin II, shock, septic shock, vasodilatory shock, distributive shock, blood pressure, double-blind, humans, and vasoconstrictor agents. Search results were filtered by year, for animal trials, irrelevant therapies, meta-analysis, retrospective studies, and case studies. Only original studies published within the last ten years that used angiotensin II for human trials in the treatment of distributive shock were included in the review. Results: Two of three studies showed statistically significant data supporting the ability of angiotensin II to increase MAP above 65 mmHg; however, statistical significance was not found in the reduction of mortality. Conclusion: The addition of angiotensin II to current standard therapy for the treatment of distributive shock decreases the requirement for vasopressors and increases MAP. Further studies are needed to address the long-term effects of angiotensin II and to investigate outcomes in specific types of shock such as sepsis-induced and anaphylaxis

Electrophysiological correlates of high-level perception during spatial navigation

We studied the electrophysiological basis of object recognition by recording scalp\ud electroencephalograms while participants played a virtual-reality taxi driver game.\ud Participants searched for passengers and stores during virtual navigation in simulated\ud towns. We compared oscillatory brain activity in response to store views that were targets or\ud nontargets (during store search) or neutral (during passenger search). Even though store\ud category was solely defined by task context (rather than by sensory cues), frontal ...\ud \u

Multi-scale analysis and validation of the Envisat MERIS Terrestrial Chlorophyll Index (MTCI) in woodland

Satellite remote sensing can be used to estimate and monitor the chlorophyll content of vegetation canopies which are a key and dynamic component of global terrestrial ecosystems. The red-edge algorithm can be used to estimate chlorophyll content from remotely sensed data but is unsuitable for use with most satellite sensor imagery. To overcome this problem, the new Envisat MERIS Terrestrial Chlorophyll index (MTCI) has been developed. It is the only operational satellite chlorophyll index and MTCI data are available as a Level 2 product from the European Space Agency. However, there is a need to ‘validate’ the MTCI over a wide range of environmental conditions. This paper reports on research that attempts to validate the MTCI using Compact Airborne Spectrographic Imager (CASI) imagery and ground data of chlorophyll content. The study site was predominantly woodland in the south of England (New Forest National Park) and had a wide range of chlorophyll contents. A transfer function derived from CASI data was used to produce a reference map of chlorophyll content, when aggregated it was compared to MERIS MTCI data and used to derive the MTCI – chlorophyll content relationship (R squared = 0.56)

Information content of ozone retrieval algorithms

The algorithms are characterized that were used for production processing by the major suppliers of ozone data to show quantitatively: how the retrieved profile is related to the actual profile (This characterizes the altitude range and vertical resolution of the data); the nature of systematic errors in the retrieved profiles, including their vertical structure and relation to uncertain instrumental parameters; how trends in the real ozone are reflected in trends in the retrieved ozone profile; and how trends in other quantities (both instrumental and atmospheric) might appear as trends in the ozone profile. No serious deficiencies were found in the algorithms used in generating the major available ozone data sets. As the measurements are all indirect in someway, and the retrieved profiles have different characteristics, data from different instruments are not directly comparable

The Probability Distribution of Binary Pulsar Coalescence Rate Estimates. II. Neutron Star-White Dwarf Binaries

We consider the statistics of pulsar binaries with white dwarf companions (NS-WD). Using the statistical analysis method developed by Kim et al. (2003) we calculate the Galactic coalescence rate of NS-WD binaries due to gravitational-wave emission. We find that the most likely values for the total Galactic coalescence rate (R_tot) of NS-WD binaries lie in the range 0.2--10 per Myr depending on different assumed pulsar population models. For our reference model, we obtain R_tot=4.11_(-2.56)^(+5.25) per Myr at a 68% statistical confidence level. These rate estimates are not corrected for pulsar beaming and as such they are found to be about a factor of 20 smaller than the Galactic coalescence rate estimates for double neutron star systems. Based on our rate estimates, we calculate the gravitational-wave background due to coalescing NS-WD binaries out to extragalactic distances within the frequency band of the Laser Interferometer Space Antenna. We find the contribution from NS-WD binaries to the gravitational-wave background to be negligible.Comment: 20 pages, 2 figures, 2 tables, Accepted for publication in Ap