7,181 research outputs found
Nasion Swelling as the Presenting Symptom of Lung Adenocarcinoma
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
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 . Second, there exist two types of Yukawa couplings
with different strengths: the lepton-number conserving couplings 's and the
lepton-number violating ones 's satisfying the condition in which the second
are much smaller than the first ones: .
With the acceptable set of parameters, numerical evaluation shows that in
this model, masses of the exotic quarks also have different scales, namely, the
exotic quark () gains mass 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
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
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: , , \om\sim
O(1) \mathrm{TeV} and . 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
in orders of and degenerate in
, while the Dirac masses get a large reduction down to
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?
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
Joint Research on Environmental Science and Technology for the Eart
Photoconductive UV Detectors Based on ZnO Films Prepared by R.F. Magnetron Sputtering Method
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 A 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
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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