122 research outputs found
Systematic evaluation of cryptic freshwater snails from central Chile, including the enigmatic Littoridina santiagensis (Gastropoda, Truncatelloidea)
In 1944, Walter Biese described Littoridina santiagensis (Cochliopidae) from Estero Dehesa based exclusively on external shell features and a second allopatric population in Yeso Spring three years later. Different samplings carried out since 2011 in the type locality have only provided specimens of the morphologically similar invasive mudsnail Potamopyrgus antipodarum (Tateidae) raising doubts about the identity of the species. The recent finding of two snail morphotypes in Yeso Spring, a thick shelled form congruent with type specimens of L. santiagensis and a slender one morphologically associable to P. antipodarum, allowed comparative studies, including the taxonomic analysis of additional populations with similar shell morphology occurring in central Chile. A DNA barcoding (COI) approach identified the slender form from Yeso Spring in Maipo Basin and a second population from the contiguous Rapel Basin indeed as the invasive P. antipodarum, however, L. santiagensis was recovered among species of Potamolithus (Tateidae) justifying the binomem Potamolithus santiagensis as a new combination. Besides recognition of other three populations as belonging to Potamolithus, the molecular analysis also suggests trans-Andean dispersal of this group of snails in the Southern Cone of South America.Fil: Collado, Gonzalo A.. Universidad del Bio Bio; ChileFil: Aguayo, Karina P.. Universidad del Bio Bio; ChileFil: Cazzaniga, Néstor Jorge. Universidad Nacional del Sur; ArgentinaFil: Gutierrez Gregoric, Diego Eduardo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: de Lucia, Micaela. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Invertebrados; ArgentinaFil: Haase, Martin. University of Greifswald; Alemani
Perturbed Field Ionization for Improved State Selectivity
Selective field ionization (SFI) is used to determine the state or distribution of states to which a Rydberg atom is excited. By evolving a small perturbation to the ramped electric field using a genetic algorithm, the shape of the time-resolved ionization signal can be controlled. This allows for the separation of signals from pairs of states that would be indistinguishable with unperturbed SFI. Measurements and calculations are presented that demonstrate this technique and shed light on how the perturbation directs the pathway of the electron to ionization. Pseudocode for the genetic algorithm is provided. Using the improved resolution afforded by this technique, quantitative measurements of the 36p3/2 + 36p3/2 --\u3e 36s1/2 + 37s1/2 dipole–dipole interaction are made
Revisión de 5 casos de sarcoidosis pulmonar
La Sarcoidosis es una patología de alta prevalencia a nivel mundial y con heterogeneidad en la presentación clínica. Nuestro objetivo consiste en revisar en una serie de casos de Sarcoidosis las manifestaciones sistémicas y órgano específicas, imagenológicas y de laboratorio previas y posteriores al tratamiento.Facultad de Ciencias Médica
Revisión de 5 casos de sarcoidosis pulmonar
La Sarcoidosis es una patología de alta prevalencia a nivel mundial y con heterogeneidad en la presentación clínica. Nuestro objetivo consiste en revisar en una serie de casos de Sarcoidosis las manifestaciones sistémicas y órgano específicas, imagenológicas y de laboratorio previas y posteriores al tratamiento.Facultad de Ciencias Médica
Coronary Flow Capacity and Survival Prediction after Revascularization: Physiological Basis and Clinical Implications
BACKGROUND AND AIMS: Coronary flow capacity (CFC) is associated with an observed 10-year survival probability for individual patients before and after actual revascularization for comparison to virtual hypothetical ideal complete revascularization.
METHODS: Stress myocardial perfusion (mL/min/g) and coronary flow reserve (CFR) per pixel were quantified in 6979 coronary artery disease (CAD) subjects using Rb-82 positron emission tomography (PET) for CFC maps of artery-specific size-severity abnormalities expressed as percent left ventricle with prospective follow-up to define survival probability per-decade as fraction of 1.0.
RESULTS: Severely reduced CFC in 6979 subjects predicted low survival probability that improved by 42% after revascularization compared with no revascularization for comparable severity (P = .0015). For 283 pre-and-post-procedure PET pairs, severely reduced regional CFC-associated survival probability improved heterogeneously after revascularization (P \u3c .001), more so after bypass surgery than percutaneous coronary interventions (P \u3c .001) but normalized in only 5.7%; non-severe baseline CFC or survival probability did not improve compared with severe CFC (P = .00001). Observed CFC-associated survival probability after actual revascularization was lower than virtual ideal hypothetical complete post-revascularization survival probability due to residual CAD or failed revascularization (P \u3c .001) unrelated to gender or microvascular dysfunction. Severely reduced CFC in 2552 post-revascularization subjects associated with low survival probability also improved after repeat revascularization compared with no repeat procedures (P = .025).
CONCLUSIONS: Severely reduced CFC and associated observed survival probability improved after first and repeat revascularization compared with no revascularization for comparable CFC severity. Non-severe CFC showed no benefit. Discordance between observed actual and virtual hypothetical post-revascularization survival probability revealed residual CAD or failed revascularization
Exposure assessment of radon in the drinking water supplies: a descriptive study in Palestine
<p>Abstract</p> <p>Background</p> <p>Radon gas is considered as a main risk factor for lung cancer and found naturally in rock, soil, and water. The objective of this study was to determine the radon level in the drinking water sources in Nablus city in order to set up a sound policy on water management in Palestine.</p> <p>Methods</p> <p>This was a descriptive study carried out in two phases with a random sampling technique in the second phase. Primarily, samples were taken from 4 wells and 5 springs that supplied Nablus city residents. For each source, 3 samples were taken and each was analyzed in 4 cycles by RAD 7 device manufactured by Durridge Company. Secondly, from the seven regions of the Nablus city, three samples were taken from the residential tap water of each region. Regarding the old city, ten samples were taken. Finally, the mean radon concentration value for each source was calculated.</p> <p>Results</p> <p>The mean (range) concentration of radon in the main sources were 6.9 (1.5-23.4) Becquerel/liter (Bq/L). Separately, springs and wells' means were 4.6 Bq/L and 9.5 Bq/L; respectively. For the residential tap water in the 7 regions, the results of the mean (range) concentration values were found to be 1.0 (0.9-1.3) Bq/L. For the old city, the mean (range) concentration values were 2.3 (0.9-3.9) Bq/L.</p> <p>Conclusions</p> <p>Except for Al-Badan well, radon concentrations in the wells and springs were below the United State Environmental Protection Agency maximum contaminated level (U.S EPA MCL). The level was much lower for tap water. Although the concentration of radon in the tap water of old city were below the MCL, it was higher than other regions in the city. Preventive measures and population awareness on radon's exposure are recommended.</p
Morphological and molecular analysis of cryptic native and invasive freshwater snails in Chile
Species delimitation in minute freshwater snails is often difcult to perform using solely shell morphology. The problem intensifes when invasive species spread within the distribution range of morphologically similar native species. In Chile, the Truncatelloidean snails are represented by the native genera Heleobia and Potamolithus plus the invasive mudsnail Potamopyrgus antipodarum, which can easily be confused. Using an integrative approach, we performed molecular phylogenetic analysis and studied reproductive and morphological features to identify superfcially similar forms inhabiting the central area of the country. Truncatelloidean snails were identifed in 40 of 51 localities sampled, 10 containing Potamopyrgus antipodarum, 23 Heleobia and 7 Potamolithus. Based on these results and previously published data, the known distribution of the mudsnail in Chile encompasses 6 hydrological basins, including 18 freshwater ecosystems. The fnding of the mudsnails in several type localities of native species/subspecies of “Heleobia” that were not fnd in situ suggests species replacement or signifcant extinction of native fauna, a hypothesis supported by the restudy of type material that shows that endemic forms belong to the genus Potamolithus. This study shows the usefulness of integrative taxonomy not only resolving complex taxa with cryptic morphology but also measuring the extent of an ongoing invasion.Facultad de Ciencias Naturales y Muse
Experimental neck muscle pain impairs standing balance in humans
Impaired postural control has been reported in patients with chronic neck
pain of both traumatic and non-traumatic etiologies, but whether painful
stimulation of neck muscle per se can affect balance control during quiet
standing in humans remains unclear. The purpose of the present experiment was
thus to investigate the effect of experimental neck muscle pain on standing
balance in young healthy adults. To achieve this goal, 16 male university
students were asked to stand upright as still as possible on a force platform
with their eyes closed in two conditions of No pain and Pain of the neck
muscles elicited by experimental painful electrical stimulation. Postural
control and postural performance were assessed by the displacements of the
center of foot pressure (CoP) and of the center of mass (CoM), respectively.
The results showed increased CoP and CoM displacements variance, range, mean
velocity, and mean and median frequencies in the Pain relative to the No pain
condition. The present findings emphasize the destabilizing effect of
experimental neck muscle pain per se, and more largely stress the importance of
intact neck neuromuscular function on standing balance
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