Orbits and masses in the young triple system TWA 5

We aim to improve the orbital elements and determine the individual masses of the components in the triple system TWA 5. Five new relative astrometric positions in the H band were recorded with the adaptive optics system at the Very Large Telescope (VLT). We combine them with data from the literature and a measurement in the Ks band. We derive an improved fit for the orbit of TWA 5Aa-b around each other. Furthermore, we use the third component, TWA 5B, as an astrometric reference to determine the motion of Aa and Ab around their center of mass and compute their mass ratio. We find an orbital period of 6.03+/-0.01 years and a semi-major axis of 63.7+/-0.2 mas (3.2+/-0.1 AU). With the trigonometric distance of 50.1+/-1.8 pc, this yields a system mass of 0.9+/-0.1 Msun, where the error is dominated by the error of the distance. The dynamical mass agrees with the system mass predicted by a number of theoretical models if we assume that TWA5 is at the young end of the age range of the TW Hydrae association. We find a mass ratio of M_Ab / M_Aa = 1.3 +0.6/-0.4, where the less luminous component Ab is more massive. This result is likely to be a consequence of the large uncertainties due to the limited orbital coverage of the observations.Comment: 9 pages, 8 figures, accepted by Astronomy and Astrophysic

Self-similar dynamics for the modified Korteweg-de Vries equation

We prove a local well posedness result for the modified Korteweg-de Vries equa- tion in a critical space designed so that is contains self-similar solutions. As a consequence, we can study the flow of this equation around self-similar solutions: in particular, we give an as- ymptotic description of small solutions as t → +∞ and construct solutions with a prescribed blow up behavior as t → 0

Beyond the operating room: do hospital characteristics have an impact on surgical site infections after colorectal surgery? A systematic review

Background: Hospital characteristics have been recognized as potential risk factors for surgical site infection for over 20 years. However, most research has focused on patient and procedural risk factors. Understanding how structural and process variables influence infection is vital to identify targets for effective interventions and to optimize healthcare services. The aim of this study was to systematically review the association between hospital characteristics and surgical site infection in colorectal surgery. Main body: A systematic literature search was conducted using PubMed, Scopus and Web of Science databases until the 31st of May, 2021. The search strategy followed the Participants, Exposure/Intervention, Comparison, Outcomes and Study design. The primary outcome of interest was surgical site infection rate after colorectal surgery. Studies were grouped into nine risk factor typologies: hospital size, ownership affiliation, being an oncological hospital, safety-net burden, hospital volume, surgeon caseload, discharge destination and time since implementation of surveillance. The STROBE statement was used for evaluating the methodological quality. A total of 4703 records were identified, of which 172 were reviewed and 16 were included. Studies were published between 2008 and 2021, and referred to data collected between 1996 and 2016. Surgical site infection incidence ranged from 3.2 to 27.6%. Two out of five studies evaluating hospital size adjusted the analysis to patient and procedure-related risk factors, and showed that larger hospitals were either positively associated or had no association with SSI. Public hospitals did not present significantly different infection rates than private or non-profit ones. Medical school affiliation and higher safety-net burden were associated with higher surgical site infection (crude estimates), while oncological hospitals were associated with higher incidence independently of other variables. Hospital caseload showed mixed results, while surgeon caseload and surveillance time since implementation appear to be associated with fewer infections. Conclusions: Although there are few studies addressing hospital-level factors on surgical site infection, surgeon experience and the implementation of a surveillance system appear to be associated with better outcomes. For hospitals and services to be efficiently optimized, more studies addressing these variables are needed that take into account the confounding effect of patient case mix.The Epidemiology Research Unit (EPIUnit, Unidade de Investigação em Epidemiologia—Instituto de Saúde Pública da Universidade do Porto) is funded by the Portuguese Foundation for Science and Technology (POCI-01-0145-FEDER-006862; Ref. ()

Asymptotics in Fourier space of self-similar solutions to the modified Korteweg-de Vries equation

We give the asymptotics of the Fourier transform of self-similar solutions to the modified Korteweg-de Vries equation, through a fixed point argument in weighted $W^{1,\infty}$ around a carefully chosen, two term ansatz. Such knowledge is crucial in the study of stability properties of the self-similar solutions for the modified Korteweg-de Vries flow. In the defocusing case, the self-similar profiles are solutions to the PainlevéII equation. Although they were extensively studied in physical space, no result to our knowledge describe their behavior in Fourier space. We are able to relate the constants involved in the description in Fourier space with those involved in the description in physical space

Asymptotics in Fourier space of self-similar solutions to the modified Korteweg-de Vries equation

We give the asymptotics of the Fourier transform of self-similar solutions for the modified Korteweg-de Vries equation. In the defocussing case, the self-similar profiles are solutions to the Painlevé II equation; although they were extensively studied in physical space, no result to our knowledge describe their behavior in Fourier space. These Fourier asymptotics are crucial in the study of stability properties of the self-similar solutions for the modified Korteweg-de Vries flow. Our result is obtained through a fixed point argument in a weighted W1,∞ space around a carefully chosen, two term ansatz, and we are able to relate the constants involved in the description in Fourier space with those of the description in physical space

Semi-automatic 3D reconstruction of urban areas using epipolar geometry and template matching

WOS:000240143800002 (Nº de Acesso Web of Science)In this work we describe a novel technique for semi-automatic three-dimensional (3D) reconstruction of urban areas, from airborne stereo-pair images whose output is VRML or DXF. The main challenge is to compute the relevant information—building's height and volume, roof's description, and texture—algorithmically, because it is very time consuming and thus expensive to produce it manually for large urban areas. The algorithm requires some initial calibration input and is able to compute the above-mentioned building characteristics from the stereo pair and the availability of the 2D CAD and the digital elevation model of the same area, with no knowledge of the camera pose or its intrinsic parameters. To achieve this, we have used epipolar geometry, homography computation, automatic feature extraction and we have solved the feature correspondence problem in the stereo pair, by using template matching

Fetopathy associated with exposure to angiotensin converting enzyme inhibitors

Angiotensin Converting Enzyme Inhibitors (ACEI) are commonly used antihypertensive drugs, although contraindicated during pregnancy by fetopathy association such as renal dysgenesis, oligohydramnios, hipocalvaria, pulmonary hypoplasia, intrauterine growth restriction, and neonatal anuric renal failure. The authors present a clinical report of a child that developed neonatal anuric renal failure with peritoneal dialysis support by an in uterus exposure to ACEI with very good recovery. This case and literature review states the need to avoid ACEI prescription to Young women and it's suspension as soon as possible during pregnancy