Interference phenomenon for the Faddeevian regularization of 2D chiral fermionic determinants

The classification of the regularization ambiguity of a 2D fermionic determinant in three different classes according to the number of second-class constraints, including the new Faddeevian regularization, is examined and extended. We find a new and important result that the Faddeevian class, with three second-class constraints, possesses a free continuous one parameter family of elements. The criterion of unitarity restricts the parameter to the same range found earlier by Jackiw and Rajaraman for the two-constraint class. We studied the restriction imposed by the interference of right-left modes of the chiral Schwinger model (χQED2) using Stone's soldering formalism. The interference effects between right and left movers, producing the massive vectorial photon, are shown to constrain the regularization parameter to belong to the four-constraint class which is the only nonambiguous class with a unique regularization parameter. ©1999 The American Physical Society.

A new firefly luciferase with bimodal spectrum: Identification of structural determinants of spectral pH-sensitivity in firefly luciferases

Fireflies emit flashes in the green-yellow region of the spectrum for the purpose of sexual attraction. The bioluminescence color is determined by the luciferases. It is well known that the in vitro bioluminescence color of firefly luciferases can be shifted toward the red by lower pH and higher temperature; for this reason they are classified as pH-sensitive luciferases. However, the mechanism and structural origin of pH sensitivity in fireflies remains unknown. Here we report the cloning of a new luciferase from the Brazilian twilight active firefly Macrolampis sp2, which displays an unusual bimodal spectrum. The recombinant luciferase displays a sensitive spectrum with the peak at 569 nm and a shoulder in the red region. Comparison of the bioluminescence spectra of Macrolampis, Photinus and Cratomorphus firefly luciferases shows that the distinct colors are determined by the ratio between green and red emitters under luciferase influence. Comparison of Macrolampis luciferase with the highly similar North American Photinus pyralis luciferase (91%) showed few substitutions potentially involved with the higher spectral sensitivity in Macrolampis luciferase. Site-directed mutagenesis showed that the natural substitution E354N determines the appearance of the shoulder in the red region of Macrolampis luciferase bioluminescence spectrum, helping to identify important interactions and residues involved in the pH-sensing mechanism in firefly luciferases. © 2005 American Society for Photobiology.

Excision of an atypical case of palatal bone exostosis: a case report.

Bone exostosis has long been described in the literature, appearing in most cases as a torus palatinus or mandibularis. These two variations are relatively common and affect approximately 30% of the world's population. Incidence is even higher when human skulls are examined post mortem, indicating that in some cases the exostosis is small and cannot be seen under the soft tissue. Removal of an exostosis is usually associated with the construction of a prothesis, but in rare cases such as the present, the lesion enlarges enough to affect speech and feeding. Few studies have reported the removal of such a large exostosis, and all were conducted in a hospital environment. In this case, complete removal was successfully conducted in an ambulatory clinic under local anesthesia.

The determinants of firms' distant collaboration. Evidence from Argentina, 1998-2001

Includes bibliography

Exploring the patterns and determinants of U.S. antidumping actions against Latin American imports, 1980-2004

Includes bibliography

Risk-adjusted poverty in Argentina: measurement and determinants

Includes bibliography

Savings in Latin America after the mid 1990s: determinants, constraints and policies

Includes bibliography

Dietary, anthropometric, and biochemical determinants of plasma high-density lipoprotein-cholesterol in free-living adults

The level of high-density lipoprotein is thought to be critical in inhibiting lesion formation as well as reducing the lipid load of preexisting atherosclerotic lesions. With the aim of determining the main determinants of plasma HDL-cholesterol (HDL-c) in free-living adults, 997 individuals (52.3 10 years, 67 females) were selected for a descriptive cross-sectional study. The used data corresponded to the baseline obtained from participants clinically selected for a lifestyle modification program. Covariables of clinical, anthropometry, food intake, aerobic fitness, and plasma biochemistry were analyzed against plasma HDL-c either as continuous or categorized variables. After adjustments for age, gender, and BMI the excess of abdominal fat along with high carbohydrate-energy intake and altered plasma triglycerides were the stronger predictors of reduced plasma HDL-c. In conclusion lifestyle interventions aiming to normalize abdominal fatness and plasma triglycerides are recommended to restore normal levels of HDL-c in these free-living adults. Copyright © 2011 Erick Prado de Oliveira et al.

Determinants of blood pressure in type 2 diabetic subjects with high occurrence of inadequate glycemic control

Study design: Association study Objective: To analyze the association between different biological/behavioral risk factors and blood pressure in a sample of type 2 diabetes mellitus patients with poor glycemic control. Methods: A sample of 121 type 2 diabetic patients was selected in the Public Healthcare System in a middle size Brazilian city. Blood pressure was measured using an aneroid device, previously calibrated. Six determinants of blood pressure were taken into count: age, hypoglycemic agents, general obesity, abdominal obesity, eating behaviors and physical activity level. Results: The type 2 diabetic patients presented mean age of 60.1±8.9 years-old and, at least, one risk factor. Eating behaviors (OR adj= 0.31 [0.12-0.75]) and sports practice (OR adj= 0.12 [0.02-0.75]) constituted protective factors associated with lower systolic blood pressure. On the other hand, age was positively associated with high systolic blood pressure (OR adj= 3.81 [1.39-10.38]). Patients with 5-6 risk factors, presented higher values of systolic and (F= 3.857; p= 0.011 [post hoc with p= 0.039]), diastolic blood pressure (F= 4.158; p= 0.008 [post hoc with p= 0.036]) and increased occurrence of hypertension (p= 0.010). Conclusion: Our findings indicate that, behavioral variables were important determinants of blood pressure in type 2 diabetic patients with poor glycemic control and clustering of behavioral and biological risk factors increase the hypertension occurrence.

Crystallographic portrayal of different conformational states of a Lys49 phospholipase A2 homologue: Insights into structural determinants for myotoxicity and dimeric configuration

Catalytically inactive phospholipase A2 (PLA2) homologues play key roles in the pathogenesis induced by snake envenomation, causing extensive tissue damage via a mechanism still unknown. Although, the amino acid residues directly involved in catalysis are conserved, the substitution of Asp49 by Arg/Lys/Gln or Ser prevents the binding of the essential calcium ion and hence these proteins are incapable of hydrolyzing phospholipids. In this work, the crystal structure of a Lys49-PLA2 homologue from Bothrops brazili (MTX-II) was solved in two conformational states: (a) native, with Lys49 singly coordinated by the backbone oxygen atom of Val31 and (b) complexed with tetraethylene glycol (TTEG). Interestingly, the TTEG molecule was observed in two different coordination cages depending on the orientation of the nominal calcium-binding loop and of the residue Lys49. These structural observations indicate a direct role for the residue Lys49 in the functioning of a catalytically inactive PLA2 homologue suggesting a contribution of the active site-like region in the expression of pharmacological effects such as myotoxicity and edema formation. Despite the several crystal structures of Lys49-PLA2 homologues already determined, their biological assembly remains controversial with two possible conformations. The extended dimer with the hydrophobic channel exposed to the solvent and the compact dimer in which the active site-like region is occluded by the dimeric interface. In the MTX-II crystal packing analysis was found only the extended dimer as a possible stable quaternary arrangement. © 2012 Elsevier B.V.

Socio-economic determinants of internal migration with special reference to Latin America and the Caribbean region

Includes bibliography

Indicators and determinants of savings for Latin America and the Caribbean

Includes bibliography