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To the Editor: Lassa fever is a zoonosis caused by Lassa virus (LASV; family Arenaviridae, genus Lassavirus). The primary reservoir of LASV is the multimammate rat (Mastomys natalensis), which is [...]

Spatial and temporal dynamics of carbon and nitrogen stable isotope signatures of the bottom-dwelling caridean shrimp Nauticaris marionis were measured during April and May between 1984 and 2000 in the vicinity of Marion Island (the Prince Edward Islands, Southern Ocean). There was one trophic-level enrichment in bulk [[delta].sup.15]N and [[delta].sup.13]C signatures between small (20 mm) specimens of N. marionis, suggesting distinct trophic differentiation among major shrimp size groups. Both [[delta].sup.15]N and [[delta].sup.13]C values of N. marionis increased with the depth, reflecting changes in their diet. There were no clear temporal trends in bulk [[delta].sup.15]N signatures of N. marionis. However, compound-specific [[delta].sup.15]N measurements of amino acids indicated that N. marionis from the inter-island realm occupied the trophic level of second order carnivores, while similarly sized shrimps in the near-shore realm were at the trophic level of first order carnivores. Compound-specific measurements also identified a change in the source of inorganic nitrogen at the base of the food web between the inter-island and nearshore realms. In contrast to the bulk [[delta].sup.15]N values, a significant shift in bulk [[delta].sup.13]C values of N. marionis was observed between 1984 and more recent years. This temporal change appears to be linked to changes in the overall productivity of the Prince Edward Island inter-island system, which could be linked to global climate change.

The authors have developed an approach to applying intelligent automation of liquid chromatography-mass spectrometry analysis for analytical screening of compound libraries using Microsoft Visual Basic macros. They performed the initial [...]

A method for introducing internal standards by direct infusion into the LC effluent for the quantitative LC-MS analysis of environmental samples is described. This postcolumn introduction method was found to be effective in correcting quantitative errors associated with matrix signal suppression. However, unlike surrogate or volumetric internal standards, the performance of the postcolumn method does not depend on the selection of an internal standard that shares identical elution time with the target analyte. As a result, either structural analogues (target analyte derivatives) or isotopically labeled compounds may be applied as effective internal standards. Furthermore, the postcolumn introduction method allows the application of one internal standard to address signal suppression effects for several analytes in a single LC-MS run. In contrast, volumetric and surrogate introduction methods require an isotopically labeled internal standard for each analyte to be quantified.

Research was conducted to find out whether the increase in plasma volume (PV) during pregnancy is caused by fluid retention or by a shift within the extracellular fluid volume (ECFV) from the interstitium toward the intravascular compartment. Total body water, ECFV and PV together with the hematocrit and plasma osmolality 4, 8 and 12 postsurgery in chronically instrumented pregnant and nonpregnant rats were measured. Results showed that the increased PV during pregnancy is due to fluid retention rather than ECFV.

A bacteria capable of anaerobic carboxylation of phenol to form benzoic acid has been isolated from a methanogenic consortium using antibiotics to remove the Clostridium species. The bacteria strain 6 is a Clostridium-related species, as its 16S rRNA and cellular fatty acid composition is similar to that of Clostridium. It is resistant to heat, chloramphenicol, and clindamycin, and has a low sensitivity to bacitracin.

The bacterial strains found in the intercellular spaces of sugarcane stems are morphologically identical to each other and to the bacteria Acetobacter diazotrophicus. The strains are also genetically similar to A. diazotrophicus because the composition of the cellular fatty acid of the strains and of A. diazotrophicus is similar. However, in the strains tested, the formation of hydrogen during nitrogenase activity is unaffected by the concentration of acetylene probably because of the formation of another type of nitrogenase in the absence of molybdenum.

A study was conducted to examine specific circulatory models which assess discharge of cardiac enzyme in dogs. Cardiac enzyme plasma functions were calculated for enhanced sudden types of ischemic heart impairment. The widening of interstitial protein area with dead myocyte volume affects protein washout from the heart, which relies on the microheterogeneity of necrotic tissue regions. The hastened discharge of enzymes into plasma following reperfusion indicates hastened cellular leakage rather than increased washout.

In December 1994, just before Mexico's financial collapse, Bill Clinton convened the 'Summit of the Americas' in Miami. It was attended by the leaders of all thirty-four Western hemisphere nations [...]

The authors, investigated the analytical capabilities of quadrupole, time-of-flight, and Fourier transform mass analyzers for liquid chromatography electrospray mass spectrometry (LC-MS) applications. They studied instrument parameters -- such as sensitivity, [...]

Electrospray ionization mass spectrometry (ESI-MS) was applied for the characterization of inorganic polyphosphates [orthophosphate, pyrophosphate, tripolyphosphate, trimetaphosphate, and tetrapolyphosphate]. The high selectivity of ESI-MS allows the detection of different polyphosphate species without preseparation by ion chromatography or capillary electrophoresis. Furthermore, ESI-MS does not require the incorporation of UV-absorbing chromophores into the analytical method for the detection of phosphates, unlike conventional UV-chromatographic methods. Limits of detection by ESI-MS were estimated to range from ~1 to 10 ng/mL The quantification of polyphosphate samples as single-component and multicomponent mixtures was investigated. Linear signal response for single-component samples ranged from the limit of detection to ~10 [micro]g/mL. Quantification of polyphosphate in streamwater is demonstrated using the standard addition method. The effect of multi-polyphosphate components and salts on signal response was also studied. For concentrations less than 2.0 [micro]g/mL, signal response from a tetrapolyphosphate sample was comparable to those obtained from tetrapolyphosphate-tripolyphosphate mixtures. Signal response obtained from tetrapolyphosphate in the presence of tripolyphosphate or [NH.sub.4][NO.sub.3] at higher concentrations (~50 [micro]g/mL and 35 [micro]g/mL, respectively) was significantly lower relative to single-component standards (~40%-70%).

To the Editor: Tamar Jacoby's article on immigration reform ('Immigration Nation,' November/December 2006) rightly argues that immigration is good for the United States. A mountain of evidence has affirmed that [...]