92 research outputs found
Sex-Specific Phenotypic Plasticity as a Complex Reaction of Human Organism to Different Environmental Conditions
Complex anthropological investigations of modern students were carried out in the three big cities of the Russian Federation (Samara, Arkhangelsk, Saransk), as well as in the villages of Mordovia. The program of morphofunctional investigation included body characteristics, body mass components (evaluated with the bioelectrical impedance analyzer âMedass-1â), physiological characteristics of cardiovascular and respiratory systems, right hand grip strength (dynamometry). To evaluate the level of sexual dimorphism, coefficient of sexual dimorphism (CSD) was used in this study. The total number of the studied subjects was 476 young women and 375 young men, from 17 to 23 years old. The results of ANOVA analyses show the presence of non-random variations for the majority of studied characteristics in the examined groups. On this basis, it is possible to consider that different environmental conditions exert significant influence on human organism, which is the core of the adaptation process. The largest distance separates the groups from the city of Saransk and Mordovian villages. It shows that the impact of social and environmental factors for rural and urban inhabitants is much larger as compared to ecological ones, e.g., latitude of the location. Comparison of the CSD values in all groups showed that the degree of adaptation potentials is considerably different in males and females for many characteristics. Thus, for body mass components, characteristics of respiratory system, height and BMI, males are more sensitive to environmental influences. For the cardiovascular system traits, the degree of fat tissue development and body mass, the strength of adaptation changes is practically equal in men and women, with slight advantages in men
Model-Based Analysis of Changes in the Morphological Characteristics of Moscow Students for the Last Two Decades
The aim of the paper is to develop a model of changes in morphological characteristics of young males and females body structure at the beginning of the 21st century. For this purpose the results of Moscow studentsâ annual screenings from 2000 to 2018 were analyzed (total number of 17â18-year-olds â 6,433 individuals). As a result, five factors describing the trends of changes were revealed and further analysis demonstrated variants of their values over time. An original model was developed, which reflected real morphological transformations in the body parameters of the young generation for the last 20 years. For both sex groups a trend towards macrosomia (gr. macros â big, soma- body) was revealed. For the boys some increase in linear traits was found with a decrease in muscularity. In girls, parabolic association between athletic characteristics and the year of investigation was found: the decrease in muscularity for the first decade, and its increase for the second one
Two-spinor Formulation of First Order Gravity coupled to Dirac Fields
Two-spinor formalism for Einstein Lagrangian is developed. The gravitational
field is regarded as a composite object derived from soldering forms. Our
formalism is geometrically and globally well-defined and may be used in
virtually any 4m-dimensional manifold with arbitrary signature as well as
without any stringent topological requirement on space-time, such as
parallelizability. Interactions and feedbacks between gravity and spinor fields
are considered. As is well known, the Hilbert-Einstein Lagrangian is second
order also when expressed in terms of soldering forms. A covariant splitting is
then analysed leading to a first order Lagrangian which is recognized to play a
fundamental role in the theory of conserved quantities. The splitting and
thence the first order Lagrangian depend on a reference spin connection which
is physically interpreted as setting the zero level for conserved quantities. A
complete and detailed treatment of conserved quantities is then presented.Comment: 16 pages, Plain TE
Magnetic operations: a little fuzzy physics?
We examine the behaviour of charged particles in homogeneous, constant and/or
oscillating magnetic fields in the non-relativistic approximation. A special
role of the geometric center of the particle trajectory is elucidated. In
quantum case it becomes a 'fuzzy point' with non-commuting coordinates, an
element of non-commutative geometry which enters into the traditional control
problems. We show that its application extends beyond the usually considered
time independent magnetic fields of the quantum Hall effect. Some simple cases
of magnetic control by oscillating fields lead to the stability maps differing
from the traditional Strutt diagram.Comment: 28 pages, 8 figure
Conformal geometry of the supercotangent and spinor bundles
We study the actions of local conformal vector fields Xâconf(M,g) on the spinor bundle of (M,g) and on its classical counterpart: the supercotangent bundle M of (M,g). We first deal with the classical framework and determine the Hamiltonian lift of conf(M,g) to M. We then perform the geometric quantization of the supercotangent bundle of (M,g), which constructs the spinor bundle as the quantum representation space. The Kosmann Lie derivative of spinors is btained by quantization of the comoment map.
The quantum and classical actions of conf(M,g) turn, respectively, the space of differential operators acting on spinor densities and the space of their symbols into conf(M,g)-modules. They are filtered and admit a common associated graded module. In the conformally flat case, the latter helps us determine the conformal invariants of both conf(M,g)-modules, in particular the conformally odd powers of the Dirac operator.Peer reviewe
Geometric Construction of Killing Spinors and Supersymmetry Algebras in Homogeneous Spacetimes
We show how the Killing spinors of some maximally supersymmetric supergravity
solutions whose metrics describe symmetric spacetimes (including and H-waves) can be easily constructed using purely geometrical and
group-theoretical methods. The calculation of the supersymmetry algebras is
extremely simple in this formalism.Comment: misprints corrected and references added. Version to appear in
Classical and Quantum Gravit
Colorectal cancer after bariatric surgery (Cric-Abs 2020): Sicob (Italian society of obesity surgery) endorsed national survey
Background: The published colorectal cancer (CRC) outcomes after bariatric surgery (BS) are conflicting, with some anecdotal studies reporting increased risks. The present nationwide survey CRIC-ABS 2020 (Colo-Rectal Cancer Incidence-After Bariatric Surgery-2020), endorsed by the Italian Society of Obesity Surgery (SICOB), aims to report its incidence in Italy after BS, comparing the two commonest laparoscopic proceduresâSleeve Gastrectomy (SG) and Roux-en-Y gastric bypass (GBP). Methods: Two online questionnairesâfirst having 11 questions on SG/GBP frequency with a follow-up of 5â10 years, and the second containing 15 questions on CRC incidence and management, were administered to 53 referral bariatric, high volume centers. A standardized incidence ratio (SIRâa ratio of the observed number of cases to the expected number) with 95% confidence intervals (CI) was calculated along with CRC incidence risk computation for baseline characteristics. Results: Data for 20,571 patients from 34 (63%) centers between 2010 and 2015 were collected, of which 14,431 had SG (70%) and 6140 GBP (30%). 22 patients (0.10%, mean age = 53 ± 12 years, 13 males), SG: 12 and GBP: 10, developed CRC after 4.3 ± 2.3 years. Overall incidence was higher among males for both groups (SG: 0.15% vs 0.05%; GBP: 0.35% vs 0.09%) and the GBP cohort having slightly older patients. The right colon was most affected (n = 13) and SIR categorized/sex had fewer values < 1, except for GBP males (SIR = 1.07). Conclusion: Low CRC incidence after BS at 10 years (0.10%), and no difference between procedures was seen, suggesting that BS does not trigger the neoplasm development
Relations between the K_{l3} and tau --> K pi nu_tau decays
We investigate the relations between the K_{l3} and tau --> K pi nu_tau
decays using the meson dominance approach. First, the experimental branching
fractions (BF) for K^-_{e3} and K^0_{e3} are used to fix two normalization
constants (isospin invariance is not assumed). Then, the BF of tau^- -->
K^*(892)^- nu_tau is calculated in agreement with experiment. We further argue
that the nonzero value of the slope parameter lambda_0 of the K^-_{mu3} and
K^0_{mu3} form factors f_0(t) implies the existence of the tau^- -->
K_0^*(1430)^- nu_tau decay. We calculate its BF, together with BF's of the
K^-_{mu3}, K^0_{mu3}, tau- --> K^- pi^0 nu_tau, and tau- --> antiK^0 pi^0
nu_tau decays, as a function of the lambda_0 parameter. At some value of
lambda_0, different for charged and neutral kaons, calculated BF's seem to
match existing data and a prediction is obtained for the tau^- --> K pi nu
decays going through the K_0^*(1430)^- resonance.Comment: 14 pages, RevTeX, epsf.sty, 3 embedded figure
Higgs branch localization in three dimensions
We show that the supersymmetric partition function of three-dimensional N =2 R-symmetric Chern-Simons-matter theories on the squashed S 3 and on S 2
7 S 1 can be computed with the so-called Higgs branch localization method, alternative to the more standard Coulomb branch localization. For theories that could be completely Higgsed by Fayet-Iliopoulos terms, the path integral is dominated by BPS vortex strings sitting at two circles in the geometry. In this way, the partition function directly takes the form of a sum, over a finite number of points on the classical Coulomb branch, of a vortex-string times an antivortex-string partition functions. \ua9 2014 The Author(s)
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