4,383 research outputs found
Accidental Father-to-Son HIV-1 Transmission During the Seroconversion Period
A 4-year-old child born to an HIV-1 seronegative mother was diagnosed with HIV-1, the main risk factor being transmission from the child's father who was seroconverting at the time of the child's birth. In the context of a forensic investigation, we aimed to identify the source of infection of the child and date of the transmission event. Samples were collected from the father and child at two time points about 4 years after the child's birth. Partial segments of three HIV-1 genes (gag, pol, and env) were sequenced and maximum likelihood (ML) and Bayesian methods were used to determine direction and estimate date of transmission. Neutralizing antibodies were determined using a single cycle assay. Bayesian trees displayed a paraphyletic-monophyletic topology in all three genomic regions, with the father's host label at the root, which is consistent with father-to-son transmission. ML trees found similar topologies in gag and pol and a monophyletic-monophyletic topology in env. Analysis of the time of the most recent common ancestor of each HIV-1 gene population indicated that the child was infected shortly after the father. Consistent with the infection history, both father and son developed broad and potent HIV-specific neutralizing antibody responses. In conclusion, the direction of transmission implicated the father as the source of transmission. Transmission occurred during the seroconversion period when the father was unaware of the infection and was likely accidental. This case shows how genetic, phylogenetic, and serological data can contribute for the forensic investigation of HIV transmission.info:eu-repo/semantics/publishedVersio
Finite-size scaling of the quasiespecies model
We use finite-size scaling to investigate the critical behavior of the
quasiespecies model of molecular evolution in the single-sharp-peak replication
landscape. This model exhibits a sharp threshold phenomenon at Q=Q_c=1/a, where
Q is the probability of exact replication of a molecule of length L and a is
the selective advantage of the master string.
We investigate the sharpness of the threshold and find that its
characteristic persist across a range of Q of order L^(-1) about Q_c.
Furthermore, using the data collapsing method we show that the normalized mean
Hamming distance between the master string and the entire population, as well
as the properly scaled fluctuations around this mean value, follow universal
forms in the critical region.Comment: 8 pages,tex. Submitted to Physical Review
Note on Dirac--K\"ahler massless fields
We obtain the canonical and symmetrical Belinfante energy-momentum tensors of
Dirac--K\"{a}hler's fields. It is shown that the traces of the energy-momentum
tensors are not equal to zero. We find the canonical and Belinfante dilatation
currents which are not conserved, but a new conserved dilatation current is
obtained. It is pointed out that the conformal symmetry is broken. The
canonical quantization is performed and the propagator of the massless fields
in the first-order formalism is found.Comment: 16 pages, minor corrections in the text, published versio
Study of adsorption process of iron colloid substances on activated carbon by ultrasound
The paper reports on the adsorption of iron colloid substances on activated carbon (PAC) Norit SA UF with using ultrasound. It is found that time of adsorption is equal to three hours. High-frequency electrical oscillation is 35 kHz. The adsorption capacity of activated carbon was determined and it is equal to about 0.25 mg iron colloid substances /mg PAC. The iron colloid substances size ranging from 30 to 360 nm was determined. The zeta potential of iron colloid substances which consists of iron (III) hydroxide, silicon compounds and natura organic substances is about (-38mV). The process of destruction iron colloid substances occurs with subsequent formation of a precipitate in the form of Fe(OH)[3] as a result of the removal of organic substances from the model solution
A lattice study of the two-dimensional Wess Zumino model
We present results from a numerical simulation of the two-dimensional
Euclidean Wess-Zumino model. In the continuum the theory possesses N=1
supersymmetry. The lattice model we employ was analyzed by Golterman and
Petcher in \cite{susy} where a perturbative proof was given that the continuum
supersymmetric Ward identities are recovered without finite tuning in the limit
of vanishing lattice spacing. Our simulations demonstrate the existence of
important non-perturbative effects in finite volumes which modify these
conclusions. It appears that in certain regions of parameter space the vacuum
state can contain solitons corresponding to field configurations which
interpolate between different classical vacua. In the background of these
solitons supersymmetry is partially broken and a light fermion mode is
observed. At fixed coupling the critical mass separating phases of broken and
unbroken supersymmetry appears to be volume dependent. We discuss the
implications of our results for continuum supersymmetry breaking.Comment: 32 pages, 12 figure
Qualidade da carne e desempenho de genótipos de suínos alimentados com dois níveis de aminoácidos.
Projeto/Plano de Ação: 16.00.300.04-00
Gluino Condensation in an Interacting Instanton Ensemble
We perform a semi-classical study of chiral symmetry breaking and of the
spectrum of the Dirac operator in QCD with adjoint fermions. For this purpose
we calculate matrix elements of the adjoint Dirac operator between instanton
zero modes and study their symmetry properties. We present simulations of the
instanton ensemble for different numbers of Majorana fermions in the adjoint
representation. These simulations provide evidence that instantons lead to
gluino condensation in supersymmetric gluodynamics.Comment: 32 pages, 5 figures, acknowledgment adde
Co infection of OMMV and OLV-1 enhances symptoms and increases both viruses accumulation and viral derived siRNAs in plants
Previous extensive field surveys in olive orchards have revealed high levels of Olive mild mosaic virus (OMMV) and Olive latent
virus 1 (OLV-1), frequently appearing in mixed infections. These viruses belong to genus Alphanecrovirus and their RNA dependent
RNA polymerase (RdRp),as well as their p6 and p8 amino acid sequences share over 87% identity
ACUTE EFFECTS OF VOLUME-ORIENTED INCENTIVE SPIROMETRY ON CHEST WALL VOLUMES IN PATIENTS AFTER STROKE.
The aim of the present study was to assess how volume-oriented incentive spirometry (IS) applied to patients after stroke modify total and compartmental chest wall volume variations, including right and left hemithorax compared to controls.20 post-stroke patients (stroke group, SG) and 20 age-matched healthy subjects (control group, CG) were studied by optoelectronic plethysmography during spontaneous quiet breathing (QB), IS and in the recovery period after IS.IS determined an increase of chest wall volume and its rib cage and abdominal compartments in both groups (p = 0.0008) and between the three instances (p < 0.0001). Compared to healthy control subjects, tidal volume of patients with stroke was 24.7\%, 18\% and 14.7\% lower during QB, , IS and post-IS, respectively. In all the three conditions the contribution of the abdominal compartment to tidal volume was greater in the stroke patients (54.1, 43.2 and 48.9\%) than controls (43.7, 40.8 and 46.1\%, p = .039). In the vast majority of patients 13/20 and 18/20 during QB and IS, respectively), abdominal expansion led rib cage expansion during inspiration. A greater asymmetry between the right and left hemithoracic expansion occurred in stroke patients compared to controls but it decreased during IS (62.5\% (p = 0.0023) QB; 19.7\% IS; and 67.6\% (p = 0.135) post-IS.IS promotes an increased expansion in all compartments of the chest wall and reduces the asymmetric expansion between right and left pulmonary rib cage and therefore it should be considered as a tool for rehabilitation
Stochastic semiclassical fluctuations in Minkowski spacetime
The semiclassical Einstein-Langevin equations which describe the dynamics of
stochastic perturbations of the metric induced by quantum stress-energy
fluctuations of matter fields in a given state are considered on the background
of the ground state of semiclassical gravity, namely, Minkowski spacetime and a
scalar field in its vacuum state. The relevant equations are explicitly derived
for massless and massive fields arbitrarily coupled to the curvature. In doing
so, some semiclassical results, such as the expectation value of the
stress-energy tensor to linear order in the metric perturbations and particle
creation effects, are obtained. We then solve the equations and compute the
two-point correlation functions for the linearized Einstein tensor and for the
metric perturbations. In the conformal field case, explicit results are
obtained. These results hint that gravitational fluctuations in stochastic
semiclassical gravity have a ``non-perturbative'' behavior in some
characteristic correlation lengths.Comment: 28 pages, RevTeX, no figure
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