3,749 research outputs found
Sodium intake and hypertension
The close relationship between hypertension and dietary sodium intake is widely recognized and supported by several studies. A reduction in dietary sodium not only decreases the blood pressure and the incidence of hypertension, but is also associated with a reduction in morbidity and mortality from cardiovascular diseases. Prolonged modest reduction in salt intake induces a relevant fall in blood pressure in both hypertensive and normotensive individuals, irrespective of sex and ethnic group, with larger falls in systolic blood pressure for larger reductions in dietary salt. The high sodium intake and the increase in blood pressure levels are related to water retention, increase in systemic peripheral resistance, alterations in the endothelial function, changes in the structure and function of large elastic arteries, modification in sympathetic activity, and in the autonomic neuronal modulation of the cardiovascular system. In this review, we have focused on the effects of sodium intake on vascular hemodynamics and their implication in the pathogenesis of hypertensio
Conics constructions by pins and string: tangential and physical properties
2noopenWe introduce conic sections' construction by pins and string, without rigid linear components. In addition to well-known methods (as gardener’s ellipse), we analyze some recent constructions based on tangent properties and, as an
original contribution, extend these constructions to all kinds of conics. In this setting, the physical analysis of the string's tension permits us to smoothly analyze these
constructions since the first years of high school.
From a didactical perspective, we think that such ideas can be fruitfully adopted in laboratory activities to deepen the tangential properties of conics by a rich
interaction between mathematics and physics. Furthermore, the simplicity of the required materials allows the introduction of these manipulative activities in distance
learning.openMilici P; Salvi MMilici, P; Salvi,
Left ventricular ejection time, not heart rate, is an independent correlate of aortic pulse wave velocity.
Salvi P, Palombo C, Salvi GM, Labat C, Parati G, Benetos A. Left
ventricular ejection time, not heart rate, is an independent correlate of
aortic pulse wave velocity. J Appl Physiol 115: 1610–1617, 2013. First
published September 19, 2013; doi:10.1152/japplphysiol.00475.2013.—
Several studies showed a positive association between heart rate and
pulse wave velocity, a sensitive marker of arterial stiffness. However, no
study involving a large population has specifically addressed the dependence
of pulse wave velocity on different components of the cardiac
cycle. The aim of this study was to explore in subjects of different age the
link between pulse wave velocity with heart period (the reciprocal of
heart rate) and the temporal components of the cardiac cycle such as left
ventricular ejection time and diastolic time. Carotid-femoral pulse wave
velocity was assessed in 3,020 untreated subjects (1,107 men). Heart
period, left ventricular ejection time, diastolic time, and early-systolic
dP/dt were determined by carotid pulse wave analysis with high-fidelity
applanation tonometry. An inverse association was found between pulse
wave velocity and left ventricular ejection time at all ages (25 years,
r2 0.043; 25–44 years, r2 0.103; 45–64 years, r2 0.079; 65–84
years, r2 0.044; 85 years, r2 0.022; P 0.0001 for all). A
significant (P 0.0001) negative but always weaker correlation between
pulse wave velocity and heart period was also found, with the exception
of the youngest subjects (P0.20). A significant positive correlation was
also found between pulse wave velocity and dP/dt (P 0.0001). With
multiple stepwise regression analysis, left ventricular ejection time and
dP/dt remained the only determinant of pulse wave velocity at all ages,
whereas the contribution of heart period no longer became significant.
Our data demonstrate that pulse wave velocity is more closely related to
left ventricular systolic function than to heart period. This may have
methodological and pathophysiological implications
Landing of ‘Flying Gurnard’ in Mumbai
A rare fish ‘flying gurnard’ was landed
by a trawler operating in 70-100 m depth
in the sea off Mumbai. The species was
identified as Dactyloptena peterseni
(Nystrom, 1887) and it is reported for the
first time along the Indian coast
Molecular detection of parasites (Trematoda, Digenea: Bucephalidae and Monorchiidae) in the European flat oyster Ostrea edulis (Mollusca: Bivalvia)
Members of the globally distributed bivalve family Ostreidae (oysters) have a significant role in marine ecosystems and include species of high economic importance. In this work, we report the occurrence of digenean parasites of the families Bucephalidae (Prosorhynchoides sp.) and Monorchiidae (Postmonorchis sp.) in Mediterranean native populations of Ostrea edulis (but not in the introduced Magallana gigas). Molecular detection was based on DNA sequencing of the ribosomal intergenic spacer 2 (ITS2) marker. The importance of detecting the presence of overlooked digenean parasites in Mediterranean oysters is discussed. © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group
Bragg gravity-gradiometer using the S-P intercombination transition of Sr
We present a gradiometer based on matter-wave interference of
alkaline-earth-metal atoms, namely Sr. The coherent manipulation of the
atomic external degrees of freedom is obtained by large-momentum-transfer Bragg
diffraction, driven by laser fields detuned away from the narrow
S-P intercombination transition. We use a well-controlled
artificial gradient, realized by changing the relative frequencies of the Bragg
pulses during the interferometer sequence, in order to characterize the
sensitivity of the gradiometer. The sensitivity reaches
s for an interferometer time of 20 ms, limited only by geometrical
constraints. We observed extremely low sensitivity of the gradiometric phase to
magnetic field gradients, approaching a value 10 times lower than the
sensitivity of alkali-atom based gradiometers. An efficient double-launch
technique employing accelerated red vertical lattices from a single
magneto-optical trap cloud is also demonstrated. These results highlight
strontium as an ideal candidate for precision measurements of gravity
gradients, with potential application in future precision tests of fundamental
physics.Comment: 10 pages, 7 figure
An Evaluation Schema for the Ethical Use of Autonomous Robotic Systems in Security Applications
We propose a multi-step evaluation schema designed to help procurement agencies and others to examine the ethical dimensions of autonomous systems to be applied in the security sector, including autonomous weapons systems
Structured light techniques for 3D surface reconstruction in robotic tasks
Robotic tasks such as navigation and path planning can be greatly enhanced by a vision system capable of providing depth perception from fast and accurate 3D surface reconstruction. Focused on robotic welding tasks we present a comparative analysis of a novel mathematical formulation for 3D surface reconstruction and discuss image processing requirements for reliable detection of patterns in the image. Models are presented for a parallel and angled configurations of light source and image sensor. It is shown that the parallel arrangement requires 35\% fewer arithmetic operations to compute a point cloud in 3D being thus more appropriate for real-time applications. Experiments show that the technique is appropriate to scan a variety of surfaces and, in particular, the intended metallic parts for robotic welding tasks
A multilocus view on Mediterranean aeolid nudibranchs (Mollusca): Systematics and cryptic diversity of Flabellinidae and Piseinotecidae
Recent molecular studies revealed high level of endemism and numerous cryptic species within opisthobranchs, with Mediterranean taxa clearly understudied. Here we used genetic data from both mitochondrial and nuclear gene fragments as well as morphological data from taxonomically relevant characters to investigate the phylogenetic relationships and systematics of Mediterranean taxa of the Flabellinidae and Piseinotecidae families. Phylogenetic analyses based on Bayesian and Maximum-Likelihood methods indicate that Flabellinidae and Pisenotecidae taxa and species within the genera Flabellina, Calmella and Piseinotecus do not form monophyletic clades. These results are supported by our morphological analyses which allowed the re-evaluation of the triseriate radula condition in Pisenotecidae and Calmella taxa and their inclusion in the genus Flabellina as Flabellina gaditana comb. nov. (synonym of F. confusa), Flabellina gabinierei comb. nov. and Flabellina cavolini comb. nov. Species delimitation and barcoding gap analyses allowed uncovering cryptic species within Flabellina gracilis (Alder and Hancock, 1844), F. trophina (Bergh, 1890), F. verrucosa (M. Sars, 1829) and F. ischitana Hirano and Thompson, 1990, the latter with an Atlantic form which is under description. This study corroborates the relevance of combining molecular and morphological data from multiple populations and species in the assessment of nudibranch diversity and classification
Multiple carcasses of Olive Ridleys along Malvan Beach
The Olive Ridley turtle (Lepidochelys olivacea) is protected under the Indian Wildlife (Protection) Act, 1972. Maharashtra government along with NGOs are undertaking several efforts in conservation of sea turtles along the coast. There is a state sponsored incentive program of `500 for locating and sharing information with forest officials. Malvan coast in Sindhudurg district of Maharashtra is known for turtle and fisheries interactions. Occasional turtle nestings can be seen between November to April
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