4,650 research outputs found
Thermal equilibrium of two quantum Brownian particles
The influence of the environment in the thermal equilibrium properties of a
bipartite continuous variable quantum system is studied. The problem is treated
within a system-plus-reservoir approach. The considered model reproduces the
conventional Brownian motion when the two particles are far apart and induces
an effective interaction between them, depending on the choice of the spectral
function of the bath. The coupling between the system and the environment
guarantees the translational invariance of the system in the absence of an
external potential. The entanglement between the particles is measured by the
logarithmic negativity, which is shown to monotonically decrease with the
increase of the temperature. A range of finite temperatures is found in which
entanglement is still induced by the reservoir.Comment: 8 pages, 1 figur
Universal dissipation scaling for non-equilibrium turbulence
It is experimentally shown that the non-classical high Reynolds number energy
dissipation behaviour, ,
observed during the decay of fractal square grid-generated turbulence is also
manifested in decaying turbulence originating from various regular grids. For
sufficiently high values of the global Reynolds numbers , .Comment: 5 pages, 6 figure
Cerebral Abscess in a Patient with Rendu-Osler-Weber
A telangiectasia hemorrágica hereditária é uma doença familiar rara, descrita pela primeira vez no final do século 19, caracterizada por telangiectasias mucocutâneas e viscerais, e por malformações arteriovenosas. Manifestações neurológicas ocorrem em 8 a 12% dos doentes e resultam em mais de metade dos casos
de malformações arteriovenosas pulmonares. A telangiectasia hemorrágica hereditária é uma das causas mais frequentes de abcessos cerebrais recorrentes, múltiplos e bilaterais, tendendo estes a ocorrerem na 3a para a 5a década. Apresentamos o caso de uma mulher de 88 anos admitida por prostração, febre e insuficiência respiratória, com a suspeita de metastização pulmonar de neoplasia oculta, cuja investigação revelou, entretanto, um abcesso cerebral secundário a malformações arteriovenosas pulmonares.
Apesar da antibioterapia e da drenagem cirúrgica do abcesso, a paciente veio a falecer. O prognóstico após drenagem dos abcessos sem ressecção das lesões pulmonares é desfavorável, podendo sua elevada mortalidade refletir um atraso diagnóstico pela falta de reconhecimento dessa associação.info:eu-repo/semantics/publishedVersio
Microbial plankton communities in the coastal southeastern Black Sea: Biomass, composition and trophic interactions
We investigated biomass and composition of the pico-, nano- and microplankton communities in a coastal station of the southeastern Black Sea during 2011. We also examined trophic interactions within these communities from size-fractionated dilution experiments in February, June and December. Autotrophic and heterotrophic biomasses showed similar seasonal trends, with a peak in June, but heterotrophs dominated throughout the year. Autotrophic biomass was mainly comprised by nanoflagellates and diatoms in the first half of the year, and by dinoflagellates and Synechococcus spp. in the second half. Heterotrophic biomass was mostly dominated by heterotrophic bacteria, followed by nanoflagellates and microzooplankton. Dilution experiments suggest that nano- and microzooplankton were significant consumers of autotrophs and heterotrophic bacteria. More than 100% of bacterial production was consumed by grazers in all experiments, while 46%, 21% and 30% of daily primary production were consumed in February, June and December, respectively. In February, autotrophs were the main carbon source, but in December, it was heterotrophic bacteria. An intermediate situation was observed in June, with similar carbon flows from autotrophs and heterotrophic bacteria. Size-fraction dilution experiments suggested that heterotrophic nanoflagellates are an important link between the high heterotrophic bacterial biomass and microzooplankton. In summary, these results indicate that nano- and microzooplankton were responsible for comprising a significant fraction of total microbial plankton biomass, standing stocks, growth and grazing processes. This suggests that in 2011, the microbial food web was an important compartment of the planktonic food web in the coastal southeastern Black Sea
Abcessos Hepáticos Recidivantes Provocados por Klebsiella Pneumoniae num Homem Diabético Não Asiático
The Klebsiella pneumoniae invasive syndrome, first described in Asia, is being reported in other parts of the world. It causes liver abcsesses, with or without extrahepatic lesions. Diabetes mellitus is the most common hosts’ underlying condition. It’s frequent among asian people, even outside Asia, appearing to exist genetic factors, not yet established, increasing the risk.
We present a case of a 55-year-old portuguese white diabetic man, who had a previous hospital admittion due to Klebsiella penumoniae pneumonia and a two-week latter diagnosis of liver abcsess. 4 years latter he was readmitted with nausea, chills, fever and myalgias. He had elevated inflammatory markers and the CT-scan showed 2 liver abscesses. Klebsiella pneumoniae was isolated in blood and antibiotics were given with complete clinical and imaging resolution. We present this case of relapsing Klebsiella pneumonia liver abscesses in a non-asian man emphasizing the growing incidence of this condition in Europe.info:eu-repo/semantics/publishedVersio
Decoherence by electromagnetic fluctuations in double-quantum-dot charge qubits
We discuss decoherence due to electromagnetic fluctuations in charge qubits
formed by two lateral quantum dots. We use an effective circuit model to
evaluate correlations of voltage fluctuations in the qubit setup. These
correlations allows us to estimate energy (T1) and phase (T2) relaxation times
of the the qubit system. Our theoretical estimate of the quality factor due to
dephasing by electromagnetic fluctuations yields values much higher than those
found in recent experiments, indicating that other sources of decoherence play
a dominant role.Comment: 12 pages, 5 figure
First Results from Nb3Sn Coatings of 2.6 GHz Nb SRF Cavities Using DC Cylindrical Magnetron Sputtering System
A DC cylindrical magnetron sputtering system has been commissioned and
operated to deposit Nb3Sn onto 2.6 GHz Nb SRF cavities. After optimizing the
deposition conditions in a mock-up cavity, Nb-Sn films are deposited first on
flat samples by multilayer sequential sputtering of Nb and Sn, and later
annealed at 950 {\deg}C for 3 hours. X-ray diffraction of the films showed
multiple peaks for the Nb3Sn phase and Nb (substrate). No peaks from any Nb3Sn
compound other than Nb3Sn were detected. Later three 2.6 GHz Nb SRF cavities
are coated with ~1 m thick Nb3Sn. The first Nb3Sn coated cavity reached
close to Eacc = 8 MV/m, demonstrating a quality factor Q0 of 3.2 x 108 at Tbath
= 4.4 K and Eacc = 5 MV/m, about a factor of three higher than that of Nb at
this temperature. Q0 was close to 1.1 x 109, dominated by the residual
resistance, at 2 K and Eacc = 5 MV/m. The Nb3Sn coated cavities demonstrated Tc
in the range of 17.9 - 18 K. Here we present the commissioning experience,
system optimization, and the first results from the Nb3Sn fabrication on flat
samples and SRF cavities.Comment: 21st Intl Conf Radio Frequency Superconductivity (SRF 2023
Is there any clinical relevant difference between non mosaic Klinefelter Syndrome patients with or without Androgen Receptor variations?
Klinefelter Syndrome (KS) is the most common chromosomal disorder in men leading to non-obstructive azoospermia. Spermatozoa can be found by TESE in about 50% of adults with KS despite severe testicular degeneration. We evaluated AR variations and polymorphism length in 135 non-mosaic KS patients, aimed to find possible correlation with clinical features, sex hormones and sperm retrieval. Among 135 KS patients we found AR variations in eight subjects (5.9%). All variations but one caused a single amino acid substitution. Four variations P392S, Q58L, L548F, A475V found in six patients had been previously described to be associated with different degrees of androgen insensitivity. Moreover we observed in two patients Y359F and D732D novel variations representing respectively a missense variation and a synonymous variation not leading to amino acid substitution. All the Klinefelter patients with AR gene variations were azoospermic. Spermatozoa were retrieved with TESE for two men (40%), sperm retrieval was unsuccessful in other 3 patients. This is the only study reporting AR variations in KS patients. Relevant clinical differences not emerged between AR mutated and not AR mutated KS patients, but does each variation play an important role in the trasmission to the offspring obtained by ART in this patients
Role of viral infections in testicular cancer etiology: Evidence from a systematic review and meta-analysis
Detecting Community Structure in Dynamic Social Networks Using the Concept of Leadership
Detecting community structure in social networks is a fundamental problem
empowering us to identify groups of actors with similar interests. There have
been extensive works focusing on finding communities in static networks,
however, in reality, due to dynamic nature of social networks, they are
evolving continuously. Ignoring the dynamic aspect of social networks, neither
allows us to capture evolutionary behavior of the network nor to predict the
future status of individuals. Aside from being dynamic, another significant
characteristic of real-world social networks is the presence of leaders, i.e.
nodes with high degree centrality having a high attraction to absorb other
members and hence to form a local community. In this paper, we devised an
efficient method to incrementally detect communities in highly dynamic social
networks using the intuitive idea of importance and persistence of community
leaders over time. Our proposed method is able to find new communities based on
the previous structure of the network without recomputing them from scratch.
This unique feature, enables us to efficiently detect and track communities
over time rapidly. Experimental results on the synthetic and real-world social
networks demonstrate that our method is both effective and efficient in
discovering communities in dynamic social networks
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