895 research outputs found
Energy loss mechanism for suspended micro- and nanoresonators due to the Casimir force
A so far not considered energy loss mechanism in suspended micro- and
nanoresonators due to noncontact acoustical energy loss is investigated
theoretically. The mechanism consists on the conversion of the mechanical
energy from the vibratory motion of the resonator into acoustic waves on large
nearby structures, such as the substrate, due to the coupling between the
resonator and those structures resulting from the Casimir force acting over the
separation gaps. Analytical expressions for the resulting quality factor Q for
cantilever and bridge micro- and nanoresonators in close proximity to an
underlying substrate are derived and the relevance of the mechanism is
investigated, demonstrating its importance when nanometric gaps are involved
Nuevos registros de hiedevivos (Insecta: Hemiptera: Pentatomidae) para la RepĂșblica Dominicana y la Hispaniola, incluyendo el nuevo hallazgo de Piezosternum subulatum (Thunberg, 1783)
Se registran las especies Oebalus linki (Heidemann, 1917) y Podisus subferrugineus Barber et Bruner, 1932, por primera vez para la RepĂșblica Domincana y La Hispaniola. TambiĂ©n se presenta el nuevo hallazgo de Piezosternum subulatum (Thunberg, 1783) luego de 200 años sin registros
Quantum capacitor with discrete charge-anticharge: spectrum and forces
The quantum capacitor with discrete charge is modeled by a Hamiltonian
containing an inductive intrinsic term (tunnel effect between plates). The
spectrum is obtained using a double Hilbert space. Fluctuations in the
charge-anticharge pairs (zero total charge) give rise to an elementary
attraction which is compared to the Casimir force. In this case, the
field-fluctuations force could be also interpreted as charge-fluctuations
force
An ST2âdependent role of bone marrowâderived group 2 innate lymphoid cells in pulmonary fibrosis
Recent evidence supports that bone marrow (BM)âderived hematopoietic progenitor cells play an important role in lung injury and fibrosis. While these cells give rise to multiple cell types, the ST2 (Il1rl1)âexpressing group 2 innate lymphoid cells (ILC2s) derived from BM progenitors have been implicated in tissue repair and remodeling, including in lung fibrosis. To further investigate the precise role of BMâderived ILC2s in the pathogenesis of fibrotic lung disease, their importance in the bleomycinâinduced lung fibrosis model was evaluated by analyzing the effects of selective ST2 deficiency in the BM compartment. The results showed that while ST2âsufficient control mice exhibited activation of lung ILâ33/ST2 signaling, ILC2 recruitment, ILâ13 induction, and fibrosis, these responses were significantly diminished in ST2âdeficientâBM chimera mice, with selective loss of ST2 expression only in the BM. This diminished response to bleomycin was similar to that seen in ST2 global knockout mice, suggesting the predominant importance of ST2 from the BM compartment. In wildâtype mice, ILC2 recruitment to the lung was accompanied by a concomitant decrease in ST2+ BM cells. ST2âdeficient BM cells were unresponsive to ILâ33âinduced ILC2 maturation. Finally, lineageânegative wildâtype, but not ST2âdeficient BM cells from bleomycinâtreated mice stimulated lung fibroblast type I collagen expression, which was associated with elevated TGFÎČ expression in the BM cells. Taken together, these findings suggested that the BMâderived ILC2s were recruited to fibrotic lung through the ILâ33/ST2 pathway, and contributed to fibroblast activation to promote lung fibrosis. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145267/1/path5092.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145267/2/path5092_am.pd
Nonequilibrium wetting transitions with short range forces
We analyze within mean-field theory as well as numerically a KPZ equation
that describes nonequilibrium wetting. Both complete and critical wettitng
transitions were found and characterized in detail. For one-dimensional
substrates the critical wetting temperature is depressed by fluctuations. In
addition, we have investigated a region in the space of parameters (temperature
and chemical potential) where the wet and nonwet phases coexist. Finite-size
scaling analysis of the interfacial detaching times indicates that the finite
coexistence region survives in the thermodynamic limit. Within this region we
have observed (stable or very long-lived) structures related to spatio-temporal
intermittency in other systems. In the interfacial representation these
structures exhibit perfect triangular (pyramidal) patterns in one (two
dimensions), that are characterized by their slope and size distribution.Comment: 11 pages, 5 figures. To appear in Physical Review
Benign infantile seizures with mild gastroenteritis: Study of 22 patients
AbstractPurposeTo analyze the electroclinical features, aetiology and outcome in patients with normal neurological examination and psychomotor development who presented seizures during a mild gastroenteritis (MG).Patients and methodsEvaluation of the clinical charts of 22 patients who were assessed in the Neurology Department, Hospital Nacional de PediatrĂa Prof. Dr. JP Garrahan between 1999 and 2007.ResultsTwelve patients were boys and 10 were girls, the age of onset ranged from 5 to 26 months, and the median age was 10 months. Rotavirus antigen test in stool was positive in 9 of 18 studied patients. The seizures were brief, focal with secondary generalization in 15 patients (68.5%), apparently generalized in 5 (22.5%) and focal in two (9%). Seven of the patients (35%) had more than one seizure in 24h. The interictal EEG was normal in all patients. Neuroradiological studies were performed in 19 patients with a normal result. No patient was put on long-term treatment with antiepileptic drugs. Four patients had subsequent mild gastroenteritis and two of them presented convulsions during the disease. After between 12 and 67 months of follow-up, all patients had normal psychomotor development and neurological examination.ConclusionsIn this study we confirmed the association of benign infantile seizures (BIS) and MG with or without rotavirus. The identification of this entity allows avoiding unnecessary complementary studies and treatment with antiepileptic drugs
Nonequilibrium wetting
When a nonequilibrium growing interface in the presence of a wall is
considered a nonequilibrium wetting transition may take place. This transition
can be studied trough Langevin equations or discrete growth models. In the
first case, the Kardar-Parisi-Zhang equation, which defines a very robust
universality class for nonequilibrium moving interfaces, with a soft-wall
potential is considered. While in the second, microscopic models, in the
corresponding universality class, with evaporation and deposition of particles
in the presence of hard-wall are studied. Equilibrium wetting is related to a
particular case of the problem, it corresponds to the Edwards-Wilkinson
equation with a potential in the continuum approach or to the fulfillment of
detailed balance in the microscopic models. In this review we present the
analytical and numerical methods used to investigate the problem and the very
rich behavior that is observed with them.Comment: Review, 36 pages, 16 figure
Viability of competing field theories for the driven lattice gas
It has recently been suggested that the driven lattice gas should be
described by a novel field theory in the limit of infinite drive. We review the
original and the new field theory, invoking several well-documented key
features of the microscopics. Since the new field theory fails to reproduce
these characteristics, we argue that it cannot serve as a viable description of
the driven lattice gas. Recent results, for the critical exponents associated
with this theory, are re-analyzed and shown to be incorrect.Comment: 4 pages, revtex, no figure
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