The high inclination orbit for the International Space Station poses a risk to astronauts on EVA during occasional periods of enhanced high energy particle flux from the sun known as Solar Particle Events. We are currently unable to predict these events within the few-hour lead time required for evasive action. Compounding the threat is the fact that station construction occurs during increasing solar activity and through the peak of the solar cycle. In this paper we present an overview of the risk, the current methods to provide forecasts of SPEs, and potential risk mitigation options.

Aerospace Medicine↗

PubMedDate not supplied

Orbit selection and its impact on radiation warning architecture for a human mission to Mars.

With the recent announcement of the discovery of the possibility of life on Mars, there is renewed interest in Mars missions, perhaps eventually in human missions. Astronauts on such missions are at risk to occasional periods of enhanced high energy particle flux from the sun known as Solar Particle Events. These events can pose a substantial risk to the health of the astronauts and to the on-board electronics. Effective forecast and warning of these events could provide time to take steps to minimize the risk (retreating to a safe haven, shutting down sensitive equipment, etc.) Providing that forecast capability, will require additional monitoring capability. The extent of this architecture is sensitive to the orbit selected for the transfer to and from Mars. This paper looks at the major classes of Mars missions (Conjunction and Opposition) and sub-categories of these classes and draws conclusions on the number of monitoring satellites needed for each, with a goal to reducing total system cost through optimum orbit selection.

Forecasting↗

PubMedDate not supplied

Characterization of a multicopy family of genes encoding a surface-expressed serine endoprotease in rat Pneumocystis carinii.

A unique family of genes encoding serine endoproteases related to the Saccharomyces cerevisiae serine endoprotease kexin was identified in Pneumocystis carinii. Unlike previously described serine endoprotease genes that are single copies, multiple copies of the P. carinii serine endoprotease are distributed throughout the genome. The proteins predicted by these variant genes demonstrate sequence variability, but they retain the conserved active sites associated with endoprotease activity. The serine endoprotease was localized to the organism surface by immunohistochemical and immunofluorescence studies and to the electron lucent layer of the cyst wall by immunoelectron microscopy. The findings of multiple copies of the serine endoprotease gene in the P. carinii genome, and its localization to the cell surface, suggest that this protease plays an important role in the biology of P. carinii and that antigenic variation of the surface-expressed serine endoprotease may be a strategy for immune evasion. P. carinii serine endoprotease provides a novel target for chemotherapeutic and immune-based approaches to the treatment of P. carinii pneumonia.

Amino Acid Sequence↗

PubMedDate not supplied

Hypoxia in the Gulf of Mexico.

Seasonally severe and persistent hypoxia, or low dissolved oxygen concentration, occurs on the inner- to mid-Louisiana continental shelf to the west of the Mississippi River and Atchafalaya River deltas. The estimated areal extent of bottom dissolved oxygen concentration less than 2 mg L-1 during mid-summer surveys of 1993-2000 reached as high as 16,000 to 20,000 km2. The distribution for a similar mapping grid for 1985 to 1992 averaged 8000 to 9000 km2. Hypoxia occurs below the pycnocline from as early as late February through early October, but is most widespread, persistent, and severe in June, July, and August. Spatial and temporal variability in the distribution of hypoxia exists and is, at least partially, related to the amplitude and phasing of the Mississippi and Atchafalaya discharges and their nutrient flux. Mississippi River nutrient concentrations and loadings to the adjacent continental shelf have changed dramatically this century, with an acceleration of these changes since the 1950s to 1960s. An analysis of diatoms, foraminiferans, and carbon accumulation in the sedimentary record provides evidence of increased eutrophication and hypoxia in the Mississippi River delta bight coincident with changes in nitrogen loading.

Animals↗

PubMedDate not supplied

The development of forensic clinics.

Explore the source record for details and available documents.

Canada↗

PubMedDate not supplied

Erythrocyte sedimentation, viscosity, and plasma proteins in disease detection.

In order to assess the relationships of erythrocyte sedimentation rates (ESR) and various acute phase reactants in diagnosing and following the remissions and exacerbations of various chronic diseases, multiple tests were performed on patients for whom an ESR was ordered. The Wintrobe and Westergren ESR, plasma and serum viscosity, hemoglobin, blood cell indices, fibrinogen, serum protein electrophoresis, triglycerides, and complement (C-3) were performed. A discussion of the relative merits of correcting the Wintrobe ESR by the Wintrobe anemia correction chart of the Hynes and Whitby method is presented. Although many significant correlations exist, only the Wintrobe and Westergren ESRs and plasma viscosity approached the same number of abnormal results. If the results of the Wintrobe and Westergren are combined 67 abnormal results are observed. The plasma viscosity exhibited a 10.4 percent false positive rate compared to the combined ESR's and a 6.0 percent false negative rate. The plasma viscosity was not only highly significantly correlated with the ESR's (P < < 0.001), but also with all acute phase reactants measured as well as total protein, albumin, and gamma-globulin. The plasma viscosity appears to give the best overall summation of the many non-specific changes observed in chronic disease.

Adolescent↗