39 research outputs found
Fat Content and Fatty Acids Profile in Follow-on Formulas Commercialized in CĂ´te d'Ivoire
This study evaluates the follow-on formula for infants. These products are available under several brands in the Ivorian market. In order to verify their conformity to the WHO standards a post-market control by gravimetric method and gas chromatography with mass spectrometry is executed to evaluate the quantity and quality of fat products contained in the milks of brands available in Côte d’Ivoire. Out of the nine brands of milks analyzed, only four of them were close to the values revealed by their manufacturers, whereas the other products had their values below their respective indications
GRMHD simulations of accretion onto Sgr A*: How important are radiative losses?
We present general relativistic magnetohydrodynamic (GRMHD) numerical
simulations of the accretion flow around the supermassive black hole in the
Galactic centre, Sagittarius A* (Sgr A*). The simulations include for the first
time radiative cooling processes (synchrotron, bremsstrahlung, and inverse
Compton) self-consistently in the dynamics, allowing us to test the common
simplification of ignoring all cooling losses in the modeling of Sgr A*. We
confirm that for Sgr A*, neglecting the cooling losses is a reasonable
approximation if the Galactic centre is accreting below ~10^{-8} Msun/yr i.e.
Mdot < 10^{-7} Mdot_Edd. But above this limit, we show that radiative losses
should be taken into account as significant differences appear in the dynamics
and the resulting spectra when comparing simulations with and without cooling.
This limit implies that most nearby low-luminosity active galactic nuclei are
in the regime where cooling should be taken into account.
We further make a parameter study of axisymmetric gas accretion around the
supermassive black hole at the Galactic centre. This approach allows us to
investigate the physics of gas accretion in general, while confronting our
results with the well studied and observed source, Sgr A*, as a test case. We
confirm that the nature of the accretion flow and outflow is strongly dependent
on the initial geometry of the magnetic field. For example, we find it
difficult, even with very high spins, to generate powerful outflows from discs
threaded with multiple, separate poloidal field loops.Comment: Resubmitted to MNRAS, including modifications in response to referee
report. 13 pages, 15 figure
L’INCONTINENCE URINAIRE DU POST PARTUM : INTERET DE LA REEDUCATION PERINEALE
The urinary incontinence is defined as the occurrence of involuntary urine leakage responsible for social or hygienic problem. The prevalence of symptoms of urinary incontinence increases during pregnancy and decreases spontaneously in the first three months in the postpartum. Several risk factors can be incriminated, some related to pregnancy and childbirth and others are constitutional. Prevention plays an important role and perineal rehabilitation gives good results.L’incontinence urinaire d’effort se définit comme la survenuede fuites involontaires d'urineresponsables d'un problème hygiénique ou social.La prévalence des symptômes d’incontinence urinaire augmente au cours de la grossesse puis diminue spontanément dans les trois premiers mois du post-partum. Plusieurs facteurs de risque peuvent être incriminés, certains sont liés à la grossesse et l’accouchement et d’autres sont constitutionnels. La prévention joue un rôle important et la rééducation périnéale donne de bons résultats
THROMBASTHENIE DE GLANZMANN ET GROSSESSE : A PROPOS D’UN CAS COMPLIQUE D’HEMORRAGIE DE LA DELIVRANCE
Glanzmann's thrombasthenia is a rare hereditary, having autosomal recessive transmission, due to a deficiency of platelet membrane glycoprotein GPIIbIIIa, which is responsible for a decrease in platelet aggregation. It is the source of bleeding more or less important, appearing in childhood. Its association with pregnancy is rare, and may be complicated by bleeding. Mrs F.Z, a 23 years old primigravida, reaching Glanzmann’s thrombastenia since its infancy and has a postpartum hemorrhage that could be treated medically. We tried, through this case and a review of the literature, to review the management of this rare association, which may involve the prognosis of the mother.La thrombasthénie de Glanzmann est une maladie héréditaire rare, à transmission autosomale récessive, due à un déficit de la glycoprotéine membranaire plaquettaire GPIIbIIIa responsable d’une diminution de l’agrégation plaquettaire. Elle est à l'origine d'hémorragies plus ou moins importantes, apparaissant dès l'enfance. Son association avec la grossesse est rare, et peut se compliquer de plusieurs accidents hémorragiques. Nous rapportant le cas d’une primigeste de 23ans, connue porteuse d’une thrombasthénie de Glanzmann depuis son bas âge et qui présente une hémorragie de la délivrance qui a pu être jugulée médicalement. Nous avons essayé, à travers ce cas et une revue de la littérature, de mettre le point sur la prise en charge de cette association rare, qui peut mettre en jeu le pronostic vital maternel
Current Status of Simulations
As the title suggests, the purpose of this chapter is to review the current
status of numerical simulations of black hole accretion disks. This chapter
focuses exclusively on global simulations of the accretion process within a few
tens of gravitational radii of the black hole. Most of the simulations
discussed are performed using general relativistic magnetohydrodynamic (MHD)
schemes, although some mention is made of Newtonian radiation MHD simulations
and smoothed particle hydrodynamics. The goal is to convey some of the exciting
work that has been going on in the past few years and provide some speculation
on future directions.Comment: 15 pages, 14 figures, to appear in the proceedings of the ISSI-Bern
workshop on "The Physics of Accretion onto Black Holes" (8-12 October 2012
General Overview of Black Hole Accretion Theory
I provide a broad overview of the basic theoretical paradigms of black hole
accretion flows. Models that make contact with observations continue to be
mostly based on the four decade old alpha stress prescription of Shakura &
Sunyaev (1973), and I discuss the properties of both radiatively efficient and
inefficient models, including their local properties, their expected stability
to secular perturbations, and how they might be tied together in global flow
geometries. The alpha stress is a prescription for turbulence, for which the
only existing plausible candidate is that which develops from the
magnetorotational instability (MRI). I therefore also review what is currently
known about the local properties of such turbulence, and the physical issues
that have been elucidated and that remain uncertain that are relevant for the
various alpha-based black hole accretion flow models.Comment: To be published in Space Science Reviews and as hard cover in the
Space Sciences Series of ISSI: The Physics of Accretion on to Black Holes
(Springer Publisher
Black hole spin: theory and observation
In the standard paradigm, astrophysical black holes can be described solely
by their mass and angular momentum - commonly referred to as `spin' - resulting
from the process of their birth and subsequent growth via accretion. Whilst the
mass has a standard Newtonian interpretation, the spin does not, with the
effect of non-zero spin leaving an indelible imprint on the space-time closest
to the black hole. As a consequence of relativistic frame-dragging, particle
orbits are affected both in terms of stability and precession, which impacts on
the emission characteristics of accreting black holes both stellar mass in
black hole binaries (BHBs) and supermassive in active galactic nuclei (AGN).
Over the last 30 years, techniques have been developed that take into account
these changes to estimate the spin which can then be used to understand the
birth and growth of black holes and potentially the powering of powerful jets.
In this chapter we provide a broad overview of both the theoretical effects of
spin, the means by which it can be estimated and the results of ongoing
campaigns.Comment: 55 pages, 5 figures. Published in: "Astrophysics of Black Holes -
From fundamental aspects to latest developments", Ed. Cosimo Bambi, Springer:
Astrophysics and Space Science Library. Additional corrections mad
Studying MHD and radiative processes in Sgr A*
This thesis details four different studies of accretion and emission processes around the Galactic Center Sgr A*. We are studying Sgr A* in particular because it is the closest supermassive black hole and therefore we have incomparable observational data to test our theories and predictions. However, as explained in the introduction, the physics is certainly similar to that around other supermassive black holes at the center of many other galaxies, and comparable as well to the accretion and emission processes around hundreds of millions of smaller mass black holes that are present in our Milky Way. It is interesting to understand what is happening around compact objects like black holes, because they are at the origin of the most energetic phenomena in the universe (such as jet launching) and therefore have an important role in its evolution. Moreover physical conditions around a black hole are extremely different to anything we can see and reproduce on Earth; Sgr A* is thus an excellent laboratory to test the limits of our understanding of compact objects and phenomena surrounding them
ANN Modeling of Electronic Nose Based on Co-doped SnO2 Nanofiber Sensor
We present in this paper a novel neural network based technique to create a model incorporates intelligence for electronic nose. The idea is to create intelligent models; the first one, called selector, can select exactly the nature of gas detected. The second intelligent model is a corrector, which can automatically compensate the electronic nose’s response characteristics and discriminating exactly the detected gas (nature and concentration), and make the response increases all time when the temperature increases. The electronic nose is based on Co-doped SnO2 nanofiber sensor. The MATLAB environment is used during the design phase and optimization. The method discriminates qualitatively and quantitatively between six gases. The advantage of the method is that it uses a small representative database so we can easily implement the model in an electrical simulator
Exploring plasma evolution during Sagittarius A* flares
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