951 research outputs found
On the validity of the adiabatic approximation in compact binary inspirals
Using a semi-analytical approach recently developed to model the tidal
deformations of neutron stars in inspiralling compact binaries, we study the
dynamical evolution of the tidal tensor, which we explicitly derive at second
post-Newtonian order, and of the quadrupole tensor. Since we do not assume a
priori that the quadrupole tensor is proportional to the tidal tensor, i.e. the
so called "adiabatic approximation", our approach enables us to establish to
which extent such approximation is reliable. We find that the ratio between the
quadrupole and tidal tensors (i.e., the Love number) increases as the inspiral
progresses, but this phenomenon only marginally affects the emitted
gravitational waveform. We estimate the frequency range in which the tidal
component of the gravitational signal is well described using the stationary
phase approximation at next-to-leading post-Newtonian order, comparing
different contributions to the tidal phase. We also derive a semi-analytical
expression for the Love number, which reproduces within a few percentage points
the results obtained so far by numerical integrations of the relativistic
equations of stellar perturbations.Comment: 13 pages, 1 table, 2 figures. Minor changes to match the version
appearing on Phys. Rev.
Odd and Even Lidstone-type polynomial sequences. Part 1: basic topics
Abstract Two new general classes of polynomial sequences called respectively odd and even Lidstone-type polynomials are considered. These classes include classic Lidstone polynomials of first and second kind. Some characterizations of the two classes are given, including matrix form, conjugate sequences, generating function, recurrence relations, and determinant forms. Some examples are presented and some applications are sketched
Morphological characteristics of the facial bone wall related to the tooth position in the alveolar crest in the maxillary anterior
The purpose of this study was to analyze whether the position of the tooth in the alveolar ridge influences the thickness of the facial bone wall and the distance between the cemento-enamel junction (CEJ) and osseous zenith (OZ). Cone-beam computed tomography (CBCT) scans from fifty four dentate patients were included in the study (22 male and 32 female, mean age 41. 5 years). The measurements taken included: (1). The Facial bone thickness at 7 different equidistant levels -measuring levels (ML 1-7) - between OZ and the root apex (A). (2) The CEJ -OZ distance. (3) Facial position of the tooth (FPT) relative to a straight line traced from mesial to distal interproximal depressions of the alveolar plate at the level of the CEJ. The Facial bone wall thickness ranged between 0 mm and 3. 8 mm, with greater values at more apical levels. Mean values were smaller than 1 mm at every level except ML7. The CEJ-OZ distance varied between 0. 5 mm and 6. 9 mm (mean 2. 9 mm). The Mean of FPT value was 0. 6 mm. No statistically significant correlation was found between FPT and the CEJ-OZ distance. Weak negative statistically significant correlations were found between FPT and the thickness of the facial bone wall at MP1 and MP3. Within the limits of this study, no clinically relevant correlation between FPT and facial bone thickness - CEJ-OZ distance was found. More studies should be conducted to evaluate a greater number of teeth, especially those that may present misalignment with greater FPT values.El objetivo del presente estudio fue analizar si la posición de la pieza dentaria en el reborde alveolar influencia el espesor de la tabla ósea vestibular y la distancia entre el limite amelo-cementario (LAC) y el cenit óseo (CO). Tomografías computadas haz de cono (TC) de 54 pacientes dentados fueron incluidas en el estudio (22 hombres y 32 mujeres, edad promedio 41. 5 anos). Las medidas registradas fueron: (1) espesor de la tabla ósea vestibular en 7 diferentes niveles de medición (NM1-7) entre CO y el ápice radicular (AR). (2) La distancia LAC-CO. (3) Posición vestibular de la pieza dentaria (PVD) en relación a una línea recta trazada desde la depresión interproximal mesial a la depresión interproximal distal de la tabla ósea a nivel del LAC. El espesor de la tabla ósea vestibular fue 0-3. 8mm, con valores mayores registrados a nivel más apical. El valor promedio fue menor a 1 mm excepto en NM7. La distancia LAC-CO varió entre 0. 5 y 6. 9mm (promedio 2. 9mm). El promedio de PVD fue de 0. 6mm. No se encontró correlación estadísticamente significativa entre la PVD y la distancia LAC-CO. Se halló una correlación débil negativa estadísticamente significativa entre la PVD y el espesor de la tabla ósea vestibular en NM1 y NM3. Dentro de las limitaciones de este estudio, no se encontró una correlación clínicamente significativa entre PVD y espesor de la tabla ósea vestibular - distancia LAC-CO. Se deben llevar a cabo más estudios para evaluar un mayor número de piezas dentarias, especialmente aquellas que se encuentran desalineadas con valores PVD mayores
Multi-mode TES bolometer optimization for the LSPE-SWIPE instrument
In this paper we explore the possibility of using transition edge sensor
(TES) detectors in multi-mode configuration in the focal plane of the Short
Wavelength Instrument for the Polarization Explorer (SWIPE) of the
balloon-borne polarimeter Large Scale Polarization Explorer (LSPE) for the
Cosmic Microwave Background (CMB) polarization. This study is motivated by the
fact that maximizing the sensitivity of TES bolometers, under the augmented
background due to the multi-mode design, requires a non trivial choice of
detector parameters. We evaluate the best parameter combination taking into
account scanning strategy, noise constraints, saturation power and operating
temperature of the cryostat during the flight.Comment: in Journal of Low Temperature Physics, 05 January 201
Fatal viral and bacterial septicemia in a seventeen-year-old woman with immunodepressive influenza A H1N1: an autopsy case
: The Influenza A H1N1 subtype can present with a wide spectrum of severity, from mild symptoms of influenza to severe respiratory distress. The morbidity and mortality connected to influenza are mostly associated with secondary bacterial infections. The influenza syndrome alone can cause a massive release of cytokines with dysregulation of the immune system, and it can act in synergy with other bacteria which can enhance cytokines secretion. This article deals with a case of severe pneumonia of H1N1 in a 17-year-old woman with bacterial superinfection with Staphylococcus aureus characterized by a high level of interleukine-6 (105900 pg/mL) and the appearance of severe leukopenia with immuno-suppression, such that HIV infection and hematological diseases were included in the initial differential diagnosis. After death, the autopsy confirmed the presence of severe pneumonia, in addition to an hepatic steatosis in absence of other risk factors. This case reports the rapid and lethal course of influenza A /H1N1 in a young and healthy subject without comorbidities, in an age group in which mortality is about 0.3 deaths per 100,000. The case underlines the importance of quickly diagnosis of viral infections and the differential diagnoses with other immunosuppressive diseases, which can be fatal even in adolescent and healthy subjects
Turbulent flow through random vegetation on a rough bed
River vegetation radically modifies the flow field and turbulence characteristics. To analyze the vegetation effects on the flow, most scientific studies are based on laboratory tests or numerical simulations with vegetation stems on smooth beds. Nevertheless, in this manner, the effects of bed sediments are neglected. The aim of this paper is to experimentally investigate the effects of bed sediments in a vegetated channel and, in consideration of that, comparative experiments of velocity measures, performed with an Acoustic Doppler Velocimeter (ADV) profiler, were carried out in a laboratory flume with different uniform bed sediment sizes and the same pattern of randomly arranged emergent rigid vegetation. To better comprehend the time-averaged flow conditions, the time-averaged velocity was explored. Subsequently, the analysis was focused on the energetic characteristics of the flow field with the determination of the Turbulent Kinetic Energy (TKE) and its components, as well as of the energy spectra of the velocity components immediately downstream of a vegetation element. The results show that both the vegetation and bed roughness surface deeply affect the turbulence characteristics. Furthermore, it was revealed that the roughness influence becomes predominant as the grain size becomes larger
Where is iron in erionite? A multidisciplinary study on fibrous erionite-Na from Jersey (Nevada, USA)
Fibrous erionite is a mineral fibre of great concern but to date mechanisms by which it induces cyto- and geno-toxic damage, and especially the role of iron associated to this zeolite species, remain poorly understood. One of the reasons is that we still don\u2019t know exactly where iron is in natural erionite. This work is focused on fibrous erionite-Na from Jersey (Nevada, USA) and attempts to draw a general model of occurrence of iron in erionite and relationship with toxicity mechanisms. It was found that iron is present as 6-fold coordinated Fe3+ not part of the zeolite structure. The heterogeneous nature of the sample was revealed as receptacle of different iron-bearing impurities (amorphous iron-rich nanoparticles, micro-particles of iron oxides/hydroxides, and flakes of nontronite). If iron is not part of the structure, its role should be considered irrelevant for erionite toxicity, and other factors like biopersistence should be invoked. An alternative perspective to the proposed model is that iron rich nano-particles and nontronite dissolve in the intracellular acidic environment, leaving a residue of iron atoms at specific surface sites anchored to the windows of the zeolite channels. These sites may be active later as low nuclearity groups
Non-intimate Relationships and Psychopathic Interpersonal and Affective Deficits as Risk Factors for Criminal Career: A Comparison Between Sex Offenders and Other Offenders
Sex-offenders are at risk of criminal recidivism. For the treatment to be truly effective, it must be individualized. For this purpose, an accurate assessment should focus on criminological, psychological, and psychopathological features. The present study compared sex offenders with other offenders on historical experiences (i.e., problems with violence, anti-social behaviors, problems with personal relationships, problems with substance use, traumatic experiences, and parenting style). In addition, given the association between life events and psychopathy, we explored whether the relation between life events and crime type (sexual crime vs. other types of crime) might be moderated by psychopathy traits (interpersonal and affective deficits and antisocial behavior). Eighty-eight sex offenders (76% of whom child molesters) and 102 other offenders were included. The Historical, Clinical and Risk Management - 20 item Version 3 (HCR-20V3) and Psychopathy Checklist-Revised (PCL-R) were administered. The scores of the HCR-20V3 Historical scale items were computed to assess life events. The scores of the PCL-R factors, F1 Interpersonal affective deficits and F2 Antisocial behavior, were recorded. The presence of a history of problems with non-intimate relationships was the only significant risk factor for sexual crime compared with other crimes. Interpersonal and affective deficits provided an increased likelihood of being sex offenders as compared with other offenders when problems with non-intimate relationships were possibly/partially or certainly present
Modeling the iron oxides and oxyhydroxides for the prediction of environmentally sensitive phase transformations
Iron oxides and oxyhydroxides are challenging to model computationally as
competing phases may differ in formation energies by only several kJ/mol, they
undergo magnetization transitions with temperature, their structures may
contain partially occupied sites or long-range ordering of vacancies, and some
loose structures require proper description of weak interactions such as
hydrogen bonding and dispersive forces. If structures and transformations are
to be reliably predicted under different chemical conditions, each of these
challenges must be overcome simultaneously, while preserving a high level of
numerical accuracy and physical sophistication. Here we present comparative
studies of structure, magnetization, and elasticity properties of iron oxides
and oxyhydroxides using density functional theory calculations with plane-wave
and locally-confined-atomic-orbital basis sets, which are implemented in VASP
and SIESTA packages, respectively. We have selected hematite, maghemite,
goethite, lepidocrocite, and magnetite as model systems from a total of 13
known iron oxides and oxyhydroxides; and use same convergence criteria and
almost equivalent settings in order to make consistent comparisons. Our results
show both basis sets can reproduce the energetic stability and magnetic
ordering, and are in agreement with experimental observations. There are
advantages to choosing one basis set over the other, depending on the intended
focus. In our case, we find the method using PW basis set most appropriate, and
combine our results to construct the first phase diagram of iron oxides and
oxyhydroxides in the space of competing chemical potentials, generated entirely
from first principlesComment: 46 pages - Accepted for publication in PRB (19 journal pages),
January 201
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