6,663 research outputs found

    Nasion Swelling as the Presenting Symptom of Lung Adenocarcinoma

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    AbstractMetastasis to the paranasal sinuses from lung cancer is extremely rare. Here, we reported a patient of lung adenocarcinoma presenting with nasion swelling because of metastasis to the paranasal sinuses. A review of the literature from 1966 to 2008 yielded another 15 patients. Adenocarcinoma was the most commonly encountered histologic subtype, and modern combination chemotherapy was probably the most effective treatment modality. Headache, visual disturbance, facial mass, and facial pain were the symptoms frequently associated with paranasal sinus metastasis; however, all of them were nonspecific for a metastatic tumor. A thorough history taking, ear, nose, and throat examination, and laboratory investigations are of paramount importance to achieve a correct diagnosis

    Fermion masses in the economical 3-3-1 model

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    We show that, in frameworks of the economical 3-3-1 model, all fermions get masses. At the tree level, one up-quark and two down-quarks are massless, but the one-loop corrections give all quarks the consistent masses. This conclusion is in contradiction to the previous analysis in which, the third scalar triplet has been introduced. This result is based on the key properties of the model: First, there are three quite different scales of vacuum expectation values: \om \sim {\cal O}(1) \mathrm{TeV}, v \approx 246 \mathrm{GeV} and u∼O(1)GeV u \sim {\cal O}(1) \mathrm{GeV}. Second, there exist two types of Yukawa couplings with different strengths: the lepton-number conserving couplings hh's and the lepton-number violating ones ss's satisfying the condition in which the second are much smaller than the first ones: s≪h s \ll h. With the acceptable set of parameters, numerical evaluation shows that in this model, masses of the exotic quarks also have different scales, namely, the UU exotic quark (qU=2/3q_U = 2/3) gains mass mU≈700m_U \approx 700 GeV, while the D_\al exotic quarks (q_{D_\al} = -1/3) have masses in the TeV scale: m_{D_\al} \in 10 \div 80 TeV.Comment: 20 pages, 8 figure

    Fish distribution in the Ba Che and Tien Yen rivers

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    The ichthyo-fauna in the Ba Che and Tien Yen rivers, northern Vietnam is highly diverse, with a total of 245 species determined. However, data on the distribution of fish species are not sufficiently provided for the whole area. This study was conducted from 2008 to 2011 at 27 stations from the Ba Che and Tien Yen river basins to determine the distribution of fish species according to different sections of the rivers, water bodies, seasons, and salinity levels. The results show that fish species are distributed mainly in the river (with 210 species), concentrated in the downstream area (with 213 species). Fishes are mainly collected in the dry season when the salinity level of river is high, due to seawater intrusion which also brings in 160 species of marine fish. This shows that fish distribution in the research areas is mainly dominated by the presence of marine species. While for freshwater fish, it is clearly affected by the mountainous features. Apart from the common characteristics sharing between the two river basins, but the number of both freshwater and marine fish species in the Tien Yen river are larger than those of Ba Che river, which is related to fresh water surface, river morphology, the width and location of the estuary to the sea. The downstream area is home to the fish species recorded in the Red Data Book of Vietnam and the complementary species for Vietnam, while the middle and upstream of the rivers may offer a high potential of biodiversity, with many possibly new species for science. These are important data for the conservation and sustainable development of fish resources in the Ba Che and Tien Yen river basins.

    Neutrino masses in the economical 3-3-1 model

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    We show that, in frameworks of the economical 3-3-1 model, the suitable pattern of neutrino masses arises from the three quite different sources - the lepton-number conserving, the spontaneous lepton-number breaking and the explicit lepton-number violating, widely ranging over the mass scales including the GUT one: u∼O(1)GeVu\sim O(1) \mathrm{GeV}, v≈246GeVv\approx 246 \mathrm{GeV}, \om\sim O(1) \mathrm{TeV} and M∼O(1016)GeV\mathcal{M}\sim \mathcal{O}(10^{16}) \mathrm{GeV}. At the tree-level, the model contains three Dirac neutrinos: one massless, two large with degenerate masses in the order of the electron mass. At the one-loop level, the left-handed and right-handed neutrinos obtain Majorana masses ML,RM_{L,R} in orders of 10−2−10−3eV10^{-2}-10^{-3} \mathrm{eV} and degenerate in MR=−MLM_R=-M_L, while the Dirac masses get a large reduction down to eV\mathrm{eV} scale through a finite mass renormalization. In this model, the contributions of new physics are strongly signified, the degenerations in the masses and the last hierarchy between the Majorana and Dirac masses can be completely removed by heavy particles. All the neutrinos get mass and can fit the data.Comment: 15 pages, 8 figure

    How large should whales be?

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    The evolution and distribution of species body sizes for terrestrial mammals is well-explained by a macroevolutionary tradeoff between short-term selective advantages and long-term extinction risks from increased species body size, unfolding above the 2g minimum size induced by thermoregulation in air. Here, we consider whether this same tradeoff, formalized as a constrained convection-reaction-diffusion system, can also explain the sizes of fully aquatic mammals, which have not previously been considered. By replacing the terrestrial minimum with a pelagic one, at roughly 7000g, the terrestrial mammal tradeoff model accurately predicts, with no tunable parameters, the observed body masses of all extant cetacean species, including the 175,000,000g Blue Whale. This strong agreement between theory and data suggests that a universal macroevolutionary tradeoff governs body size evolution for all mammals, regardless of their habitat. The dramatic sizes of cetaceans can thus be attributed mainly to the increased convective heat loss is water, which shifts the species size distribution upward and pushes its right tail into ranges inaccessible to terrestrial mammals. Under this macroevolutionary tradeoff, the largest expected species occurs where the rate at which smaller-bodied species move up into large-bodied niches approximately equals the rate at which extinction removes them.Comment: 7 pages, 3 figures, 2 data table

    SOME RESULTS OF AIR MONITORING QUALITY IN HANOI AND ASSESSMENT OF AIR MONITORING METHODS USED IN VIETNAM

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    Joint Research on Environmental Science and Technology for the Eart

    Photoconductive UV Detectors Based on ZnO Films Prepared by R.F. Magnetron Sputtering Method

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    Highly c-axis oriented zinc oxide (ZnO) thin films were deposited on glass substrates by radio frequency (r.f.) sputtering. The photoconductor UV detector based on ZnO films, having a metal-semiconductor-metal (MSM) structure with interdigitation configuration, were fabricated by using aluminium (Al) as a contact metal. The characteristics of dark and photocurrent of the ultraviolet (UV) detector and the UV photo-response of the detector were investigated. The linear current-voltage (I-V) characteristics under both forward and reverse bias exhibit ohmic metal-semiconductor contacts. Under illumination by monochromatic light at a wavelength of 365~nm, the photo-generated current was measured to be 0.56 μ\muA at a bias of 6 V. The photo-response decay in these devices is slow

    Ventricular divergence correlates with epicardial wavebreaks and predicts ventricular arrhythmia in isolated rabbit hearts during therapeutic hypothermia

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    INTRODUCTION: High beat-to-beat morphological variation (divergence) on the ventricular electrogram during programmed ventricular stimulation (PVS) is associated with increased risk of ventricular fibrillation (VF), with unclear mechanisms. We hypothesized that ventricular divergence is associated with epicardial wavebreaks during PVS, and that it predicts VF occurrence. METHOD AND RESULTS: Langendorff-perfused rabbit hearts (n = 10) underwent 30-min therapeutic hypothermia (TH, 30°C), followed by a 20-min treatment with rotigaptide (300 nM), a gap junction modifier. VF inducibility was tested using burst ventricular pacing at the shortest pacing cycle length achieving 1:1 ventricular capture. Pseudo-ECG (p-ECG) and epicardial activation maps were simultaneously recorded for divergence and wavebreaks analysis, respectively. A total of 112 optical and p-ECG recordings (62 at TH, 50 at TH treated with rotigaptide) were analyzed. Adding rotigaptide reduced ventricular divergence, from 0.13±0.10 at TH to 0.09±0.07 (p = 0.018). Similarly, rotigaptide reduced the number of epicardial wavebreaks, from 0.59±0.73 at TH to 0.30±0.49 (p = 0.036). VF inducibility decreased, from 48±31% at TH to 22±32% after rotigaptide infusion (p = 0.032). Linear regression models showed that ventricular divergence correlated with epicardial wavebreaks during TH (p<0.001). CONCLUSION: Ventricular divergence correlated with, and might be predictive of epicardial wavebreaks during PVS at TH. Rotigaptide decreased both the ventricular divergence and epicardial wavebreaks, and reduced the probability of pacing-induced VF during TH
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