1,226 research outputs found
Efficiency of free energy calculations of spin lattices by spectral quantum algorithms
Quantum algorithms are well-suited to calculate estimates of the energy
spectra for spin lattice systems. These algorithms are based on the efficient
calculation of the discrete Fourier components of the density of states. The
efficiency of these algorithms in calculating the free energy per spin of
general spin lattices to bounded error is examined. We find that the number of
Fourier components required to bound the error in the free energy due to the
broadening of the density of states scales polynomially with the number of
spins in the lattice. However, the precision with which the Fourier components
must be calculated is found to be an exponential function of the system size.Comment: 9 pages, 4 figures; corrected typographical and minor mathematical
error
Analisis Hasil Pemeriksaan Spesimen Darah Penderita Demam Berdarah Dengue di Jakarta Tahun 1988
Dengue Haemorrhagic Fever is an endemic and important public health disease in Indonesia. Surveillance of hospitalized case usually reported 5.000 cases annually but 10.000 cases could be reported during an outbreak period. The case fatality rate had been decreasing to 4% at present. Studies to analyse the risk factors of an area, pathophysiology of shock or bleeding, prevention, eradication and surveillance were still needed. The important Dengue Haemorrhagic Fever factors were analysed in this tudy based on the 1756 specimens tested in the Communicable Disease Research Center during the period from January1988 to Desember 1988, sent by most of the hospitals in Jakarta. The overall difference between male and female was not significant, although on January, July, September and Desember 1988 females were almost 2 times higher then males.Theoverall difference of children and adult groups were also not significant, although on February, March, November and December 1988 adults were higher 2-5 times then children. This findings were not usual. The antibody response titers during acute and convalescence period of illness was lower among children. These findings were not usual. The antibody response titers during acute and convalescence period of illness was lower among children then adults, although it was still lower then in Thailand
Clinical characteristics and management of cancer-associated acute venous thromboembolism: findings from the MASTER Registry.
Background: Clinical characteristics and management of acute deep vein thrombosis and pulmonary embolism (PE) have been reported to be different in patients with and without cancer. The aim of this paper was to provide information on clinical characteristics and management of acute venous thromboembolism in patients with cancer by means of a large prospective registry. Design and Methods: MASTER is a multicenter registry of consecutively recruited patients with symptomatic, objectively confirmed, acute venous thromboembolism. Information about clinical characteristics and management was collected by an electronic data network at the time of the index event. Results: A total of 2119 patients were enrolled, of whom 424 (20%) had cancer. The incidence of bilateral lower limb deep vein thrombosis was significantly higher in patients with cancer than in patients without cancer (8.5% versus 4.6%; p<0.01), as were the rates of iliocaval thombosis (22.6% versus 14%; p<0.001), and upper limb deep vein thrombosis (9.9% versus 4.8%; p<0.001). Major bleeding (3.3% versus 1.1%; p=0.001), in-hospital treatment (73.3% versus 66.6%; p=0.02) and inferior vena cava filter implantation (7.3% versus 4.1%; p=0.005) were significantly more frequent in patients with cancer, in whom oral anticoagulants were less often used (64.2% versus 82%; p<0.0001). Conclusions: The clinical presentation of acute venous thromboembolism is different and often more extensive in cancer patients than in patients free from malignancy. Moreover, the management of the acute phase of venous thromboembolism is more problematic in cancer patients, especially because of a higher rate of major bleeding and the need for implantation of inferior vena cava filters
Angle selective backscattered electron contrast in the low-voltage scanning electron microscope: simulation & experiment for polymers
Recently developed detectors can deliver high resolution and high contrast images of nanostructured carbon based materials in low voltage scanning electron microscopes (LVSEM) with beam deceleration. Monte Carlo Simulations are also used to predict under which exact imaging conditions purely compositional contrast can be obtained and optimised. This allows the prediction of the electron signal intensity in angle selective conditions for back-scattered electron (BSE) imaging in LVSEM and compares it to experimental signals. Angle selective detection with a concentric back scattered (CBS) detector is considered in the model in the absence and presence of a deceleration field, respectively. The validity of the model prediction for both cases was tested experimentally for amorphous C and Cu and applied to complex nanostructured carbon based materials, namely a Poly(N-isopropylacrylamide)/Poly(ethylene glycol) Diacrylate (PNIPAM/PEGDA) semi-interpenetration network (IPN) and a Poly(3-hexylthiophene-2,5-diyl) (P3HT) film, to map nano-scale composition and crystallinity distribution by avoiding experimental imaging conditions that lead to a mixed topographical and compositional contrast
Quantum simulation of spin ordering with nuclear spins in a solid state lattice
An experiment demonstrating the quantum simulation of a spin-lattice
Hamiltonian is proposed. Dipolar interactions between nuclear spins in a solid
state lattice can be modulated by rapid radio-frequency pulses. In this way,
the effective Hamiltonian of the system can be brought to the form of an
antiferromagnetic Heisenberg model with long range interactions. Using a
semiconducting material with strong optical properties such as InP, cooling of
nuclear spins could be achieved by means of optical pumping. An additional
cooling stage is provided by adiabatic demagnetization in the rotating frame
(ADRF) down to a nuclear spin temperature at which we expect a phase transition
from a paramagnetic to antiferromagnetic phase. This phase transition could be
observed by probing the magnetic susceptibility of the spin-lattice. Our
calculations suggest that employing current optical pumping technology,
observation of this phase transition is within experimental reach.Comment: 11 pages, 3 figues; Published versio
The complex TIE between macrophages and angiogenesis
Macrophages are primarily known as phagocytic immune cells, but they also play a role in diverse processes, such as morphogenesis, homeostasis and regeneration. In this review, we discuss the influence of macrophages on angiogenesis, the process of new blood vessel formation from the pre-existing vasculature. Macrophages play crucial roles at each step of the angiogenic cascade, starting from new blood vessel sprouting to the remodelling of the vascular plexus and vessel maturation. Macrophages form promising targets for both pro- and anti-angiogenic treatments. However, to target macrophages, we will first need to understand the mechanisms that control the functional plasticity of macrophages during each of the steps of the angiogenic cascade. Here, we review recent insights in this topic. Special attention will be given to the TIE2-expressing macrophage (TEM), which is a subtype of highly angiogenic macrophages that is able to influence angiogenesis via the angiopoietin-TIE pathway
Dampak Imunisasi Hepatitis B Rekombinan terhadap Penularan Vertikal Virus Hepatitis B pada Bayi di Kota Bandung, Jawa Barat
DAMPAK IMUNISASI HEPATITIS B REKOMBINAN TERHADAP PENULARAN VERTIKAL VIRUS HEPATITIS B PADA BAYI DI KOTA BANDUNG, JAWA BARA
Species recovery in the united states: Increasing the effectiveness of the endangered species act
The Endangered Species Act (ESA) has succeeded in shielding hundreds of species from extinction and improving species recovery over time. However, recovery for most species officially protected by the ESA - i.e., listed species-has been harder to achieve than initially envisioned. Threats to species are persistent and pervasive, funding has been insufficient, the distribution of money among listed species is highly uneven, and at least 10 times more species than are actually listed probably qualify for listing. Moreover, many listed species will require ongoing management for the foreseeable future to protect them from persistent threats. Climate change will exacerbate this problem and increase both species risk and management uncertainty, requiring more intensive and controversial management strategies to prevent species from going extinct
Cross-Disciplinarity in the Advance of Antarctic Ecosystem Research
The biodiversity, ecosystem services and climate variability of the Antarctic continent, and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disciplinary studies are especially important in Antarctic research. The conceptual study presented here is based on a workshop initiated by the Research Programme Antarctic Thresholds - Ecosystem Resilience and Adaption of the Scientific Committee on Antarctic Research, which focused on challenges in identifying and applying cross-disciplinary approaches in the Antarctic. Novel ideas, and first steps in their implementation, were clustered into eight themes, ranging from scale problems, risk maps, organism and ecosystem responses to multiple environmental changes, to evolutionary processes. Scaling models and data across different spatial and temporal scales were identified as an overarching challenge. Approaches to bridge gaps in the research programmes included multi-disciplinary monitoring, linking biomolecular findings and simulated physical environments, as well as integrative ecological modelling. New strategies in academic education are proposed. The results of advanced cross-disciplinary approaches can contribute significantly to our knowledge of ecosystem functioning, the consequences of climate change, and to global assessments that ultimately benefit humankind
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