180 research outputs found
Dicluster Stopping in a Degenerate Electron Gas
In this paper we report on our theoretical studies of various aspects of the
correlated stopping power of two point-like ions (a dicluster) moving in close
but variable vicinity of each other in some metallic target materials the
latter being modelled by a degenerate electron gas with appropriate densities.
Within the linear response theory we have made a comprehensive investigation of
correlated stopping power, vicinage function and related quantities for a
diproton cluster in two metallic targets, aluminum and copper, and present
detailed and comparative results for three approximations to the electron gas
dielectric function, namely the plasmon-pole approximation without and with
dispersion as well as with the random phase approximation. The results are also
compared, wherever applicable, with those for an individual projectile.Comment: 29 figures, LaTe
Surveillance of enteric virus infections in a neonatal intensive care unit.
Objective. To investigate the epidemiology of neonatal viral gastroenteritis compared to
the circulation of enteric viruses in children, 109 newborns in the NICU of Mother and
Child Department and 214 children with enteritis admitted to the \u201cG. Di Cristina\u201d Children\u2019s
Hospital in Palermo were monitored for Rotavirus, Adenovirus, Astrovirus and Norovirus
infections.
Methods. Stool samples were examined by EIA to detect viral antigens. Rotavirus strains
were subjected to P- and G-typing.
Results. A Norovirus strain was detected in one neonatal stool specimen whereas an astrovirus
strain was dectected in two neonatal specimens. No Rotavirus or Adenovirus infection
was identified among the newborn infants, while Rotavirus infections were detected
in 24.8% of the symptomatic children. Type G4P[8] constituted 43.4% of the Rotavirus
strains, followed by G2P[4] (18.9%), G3P[8] (17%), G1P[8] (13.2%) and G9P[8] (1.9%).
Overall, Norovirus, Adenovirus and Astrovirus strains were responsible for 15.4% of infections
in the paediatric population with diarrhoea.
Conclusions. Viruses are diffuse agents of infection in children with enteritis. Virological
tests have to be performed to diagnose enteric infections in the paediatric population. Maternal
immunity to common Rotavirus strains combined with the limited circulation of the
emerging G9 Rotavirus type among our population may account for the absence of Rotavirus
infections in newborn infants
Quasi-classical Molecular Dynamics Simulations of the Electron Gas: Dynamic properties
Results of quasi-classical molecular dynamics simulations of the quantum
electron gas are reported. Quantum effects corresponding to the Pauli and the
Heisenberg principle are modeled by an effective momentum-dependent
Hamiltonian. The velocity autocorrelation functions and the dynamic structure
factors have been computed. A comparison with theoretical predictions was
performed.Comment: 8 figure
Sarcoma de Kaposi clĂĄsico en una adolescente inmunocompetente
El sarcoma de Kaposi (KS) es una enfermedad prevalente en Ăfrica, se sabe de su existencia hace mĂĄs de un siglo, por lo que se le ha denominado endĂ©mico. Desde la apariciĂłn del virus de la inmunodeficiencia humana (VIH) y el sĂndrome de inmunodeficiencia adquirida (SIDA), se reconociĂł un tipo de sarcoma de Kaposi, el llamado epidĂ©mico mĂĄs agresivo y diseminado, que recientemente se ha relacionado con el virus del herpes tipo 8. El sarcoma de Kaposi clĂĄsico se presenta en pacientes ancianos como manchas vasculares discretamente sobre-elevadas que se localizan predominantemente en los miembros inferiores, rara vez sucede en la infancia. Se presenta un caso de sarcoma de Kaposi clĂĄsico en una adolescente mexicana inmunocompetente.
Abstract
Kaposiâs sarcoma (KS) is a prevalent disease in Africa and is known of its existence for more than a century, which has been called endemic. Since the emergence of HIV (HIV) and acquired immunodeficiency syndrome (AIDS), a type of Kaposiâs sarcoma more aggressive and spread was recognized recently has been linked to the virus type 8 herpes, he has called classic Kaposiâs sarcoma. It occurs in elderly patients as vascular patches localized predominantly in the lower limbs, rarely seen in childhood. We report a case of classic Kaposiâs sarcoma in an immunocompetent Mexican teenager.
 
Sarcoma de Kaposi clĂĄsico en una adolescente inmunocompetente
El sarcoma de Kaposi (KS) es una enfermedad prevalente en Ăfrica, se sabe de su existencia hace mĂĄs de un siglo, por lo que se le ha denominado endĂ©mico. Desde la apariciĂłn del virus de la inmunodeficiencia humana (VIH) y el sĂndrome de inmunodeficiencia adquirida (SIDA), se reconociĂł un tipo de sarcoma de Kaposi, el llamado epidĂ©mico mĂĄs agresivo y diseminado, que recientemente se ha relacionado con el virus del herpes tipo 8. El sarcoma de Kaposi clĂĄsico se presenta en pacientes ancianos como manchas vasculares discretamente sobre-elevadas que se localizan predominantemente en los miembros inferiores, rara vez sucede en la infancia. Se presenta un caso de sarcoma de Kaposi clĂĄsico en una adolescente mexicana inmunocompetente.
Abstract
Kaposiâs sarcoma (KS) is a prevalent disease in Africa and is known of its existence for more than a century, which has been called endemic. Since the emergence of HIV (HIV) and acquired immunodeficiency syndrome (AIDS), a type of Kaposiâs sarcoma more aggressive and spread was recognized recently has been linked to the virus type 8 herpes, he has called classic Kaposiâs sarcoma. It occurs in elderly patients as vascular patches localized predominantly in the lower limbs, rarely seen in childhood. We report a case of classic Kaposiâs sarcoma in an immunocompetent Mexican teenager.
 
The role of E1-E2 interplay in multiphonon Coulomb excitation
In this work we study the problem of a charged particle, bound in a
harmonic-oscillator potential, being excited by the Coulomb field from a fast
charged projectile. Based on a classical solution to the problem and using the
squeezed-state formalism we are able to treat exactly both dipole and
quadrupole Coulomb field components. Addressing various transition amplitudes
and processes of multiphonon excitation we study different aspects resulting
from the interplay between E1 and E2 fields, ranging from classical dynamic
polarization effects to questions of quantum interference. We compare exact
calculations with approximate methods. Results of this work and the formalism
we present can be useful in studies of nuclear reaction physics and in atomic
stopping theory.Comment: 10 pages, 6 figure
Breeding systems of floral colour forms in the Drosera cistiflora species complex
The study was supported by the National Research Foundation of South Africa (Grant 46372 to SDJ).Variation in plant breeding systems has implications for pollinatorâmediated selection on floral traits and the ecology of populations. Here we evaluate pollinator contribution to seed production, selfâcompatibility and pollen limitation in different floral colour forms of Drosera cistiflora sensu lato (Droseraceae). These insectivorous perennial plants are endemic to fynbos and renosterveld vegetation in the Cape Floristic Region of South Africa, and the species complex includes five floral colour forms (pink, purple, red, white and yellow), some of which are known to be pollinated by beetles. Controlled handâpollination experiments were conducted in 15 populations of D. cistiflora s.l. (two to four populations per floral colour form) to test whether the colour forms vary in their degree of selfâcompatibility and their ability to produce seeds through autonomous selfâfertilization. Yellowâflowered forms were highly selfâincompatible, while other floral colour forms exhibited partial selfâcompatibility. Seed set resulting from autonomous selfing was very low, and pollinator dependence indices were high in all populations. Since hand crossâpollination resulted in greater seed set than open pollination in 13 of the 15 populations, we inferred that seed production is generally pollenâlimited.Drosera cistiflora s.l. typically exhibits high levels of pollinator dependence and pollen limitation. This is unusual among Drosera species worldwide and suggests that pollinators are likely to mediate strong selection on attractive traits such as floral colour and size in D. cistiflora s.l. These results also suggest that the floral colour forms of D. cistiflora s.l. which are rare and threatened are likely to be vulnerable to local extinction if mutualisms were to collapse indefinitely.PostprintPeer reviewe
Unravelling heterogeneous malaria transmission dynamics in the Peruvian Amazon: insights from a cross-sectional survey.
BACKGROUND: Malaria remains a global health challenge, particularly in Peru's Loreto region. Despite ongoing efforts, high infection rates and asymptomatic cases perpetuate transmission. The Peruvian Ministry of Health's "Zero Malaria Plan" targets elimination. This novel study combines microscopic, molecular, and serological techniques to assess transmission intensity, identify epidemiological risk factors, and characterize species-specific patterns across villages. The findings aim to inform targeted interventions and support broader malaria elimination efforts in line with the Zero Malaria Plan initiative. METHODS: A cross-sectional malaria survey was conducted in the Zungarococha community, comprising the villages Llanchama (LL), Ninarumi (NI), Puerto Almendra (PA), and Zungarococha (ZG), using microscopic, molecular, and serological techniques to evaluate malaria transmission intensity. Statistical analysis, including multivariate-adjusted analysis, seroprevalence curves, and spatial clustering analysis, were performed to assess malaria prevalence, exposure, and risk factors. RESULTS: The survey revealed a high prevalence of asymptomatic infections (6% by microscopy and 18% by PCR), indicating that molecular methods are more sensitive for detecting asymptomatic infections. Seroprevalence varied significantly between villages, reflecting the heterogeneous malaria transmission dynamics. Multivariate analysis identified age, village, and limited bed net use as significant risk factors for malaria infection and species-specific exposure. Seroprevalence curves demonstrated community-specific patterns, with Llanchama and Puerto Almendra showing the highest seroconversion rates for both Plasmodium species. CONCLUSIONS: The study highlights the diverse nature of malaria transmission in the Loreto region, particularly nothing the pronounced heterogeneity as transmission rates decline, especially in residual malaria scenarios. The use of molecular and serological techniques enhances the detection of current infections and past exposure, aiding in the identification of epidemiological risk factors. These findings underscore the importance of using molecular and serological tools to characterize malaria transmission patterns in low-endemic areas, which is crucial for planning and implementing targeted interventions and elimination strategies. This is particularly relevant for initiatives like the Zero Malaria Plan in the Peruvian Amazon
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