946 resultados para mesh opening rigidity
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It is a distinct honor for me to help recognize the 2003 Master Conservationists tonight. Tonight's event marks the 20th anniversary of the program sponsored by the Omaha World-Herald and the Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln.
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It is a real pleasure to participate in this recognition program honoring the 2004 Master-Conservationists. We are grateful for the partnership with the Omaha World Herald in this unique program. In an effort to keep the program in tune with current developments in soil and waster conservation, a special committee is considering the idea of including conservation easements in the 2005 program. Some members of the committee are in the audience tonight. We appreciate the efforts of members of the Omaha World Herald, Natural Resources Districts, the USDA Natural-Resources Conservation Service and the Institute of Agriculture and Natural Resources in carrying out this program.
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To open this Third Vertebrate Pest Conference is a real privilege. It is a pleasure to welcome all of you in attendance, and I know there are others who would like to be meeting with us, but, for one reason or another cannot be. However, we can serve them by taking back the results of discussion and by making available the printed transactions of what is said here. It has been the interest and demand for the proceedings of the two previous conferen- ces which, along with personal contacts many of you have with the sponsoring committee, have gauged the need for continuing these meetings. The National Pest Control Association officers who printed the 1962 proceedings still are supplying copies of that conference. Two reprintings of the 1964 conference have been necessary and repeat orders from several universities indicate that those proceedings have become textbooks for special classes. When Dr. Howard mentioned in opening the first Conference in 1962 that publication of those papers would make a valuable handbook of animal control, he was prophetic, indeed. We are pleased that this has happened, but not surprised, since to many of us in this specialized field, the conferences have provided a unique opportunity to meet colleagues with similar interests, to exchange information on control techniques and to be informed by research workers of problem solving investigations as well as to hear of promising basic research. The development of research is a two-way street and we think these conferences also identify areas of inadequate knowledge, thereby stimulating needed research. We have represented here a number of types of specialists—animal ecologists, public health and transmissible disease experts, control methods specialists, public agency administration and enforcement staffs, agricultural extension people, manufacturing and sale industry representatives, commercial pest control operators, and others—and in addition to improving communications among these professional groups an equally important purpose of these conferences is to improve understanding between them and the general public. Within the term general public are many individuals and also organizations dedicated to appreciation and protection of certain animal forms or animal life in general. Proper concepts of vertebrate pest control do not conflict with such views. It is worth repeating for the record the definition of "vertebrate pest" which has been stated at our previous conferences. "A vertebrate pest is any native or introduced, wild or feral, non-human spe- cies of vertebrate animal that is currently troublesome locally or over a wide area to one or more persons either by being a general nuisance, a health hazard or by destroying food or natural resources. In other words, vertebrate pest status is not an inherent quality or fixed classification but is a circumstantial relationship to man's interests." I believe progress has been made in reducing the misunderstanding and emotion with which vertebrate pest control was formerly treated whenever a necessity for control was stated. If this is true, I likewise believe it is deserved, because control methods and programs have progressed. Control no longer refers only to population reductions by lethal means. We have learned something of alternate control approaches and the necessity for studying the total environment; where reduction of pest animal numbers is the required solution to a problem situation we have a wider choice of more selective, safe and efficient materials. Although increased attention has been given to control methods, research when we take a close look at the severity of animal damage to so many facets of our economy, particularly to agricultural production and public health, we realize it still is pitifully small and slow. The tremendous acceleration of the world's food and health requirements seems to demand expediting vertebrate pest control to effectively neutralize the enormous impact of animal damage to vital resources. The efforts we are making here at problem delineation, idea communication and exchange of methodology could well serve as both nucleus and rough model for a broader application elsewhere. I know we all hope this Third Conference will advance these general objectives, and I think there is no doubt of its value in increasing our own scope of information.
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This paper discusses some aspects related to Wireless Sensor Networks over the IEEE 802.15.4 standard, and proposes, for the very first time, a mesh network topology with geographic routing integrated to the open Freescale protocol (SMAC - Simple Medium Access Control). For this is proposed the SMAC routing protocol. Before this work the SMAC protocol was suitable to perform one hop communications only. However, with the developed mechanisms, it is possible to use multi-hop communication. Performance results from the implemented protocol are presented and analyzed in order to define important requirements for wireless sensor networks, such as robustness, self-healing property and low latency. (c) 2011 Elsevier Ltd. All rights reserved.
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Prosthetic meshes are commonly used to correct abdominal wall defects. However, the inflammatory reaction induced by these devices in the peritoneum is not completely understood. We hypothesized that nitric oxide (NO), produced by nitric oxide synthase 2 (NOS2) may modulate the response induced by mesh implants in the abdominal wall and, consequently, affect the outcome of the surgical procedure. Polypropylene meshes were implanted in the peritoneal side of the abdominal wall in wild-type and NOS2-deficient (NOS2(-/-)) mice. After 15 days tissues around the mesh implant were collected, and inflammatory markers (the cytokine interleukin 1 beta (IL-1 beta) and NO) and tissue remodeling (collagen and metalloproteinases (MMP) 2 and 9) were analyzed. The lack of NOS2-derived NO induced a higher incidence of visceral adhesions at the mesh implantation site compared with wild-type mice that underwent the same procedure (P < 0.05). Additionally, higher levels of IL-1 beta were present in the mesh-implanted NOS2(-/-) animals compared with control and wild-type mice. Mesh implantation induced collagen I and III deposition, but in smaller amounts in NOS2(-/-) mice. MMP-9 activity after the surgical procedure was similarly increased in both groups. Conversely, MMP-2 activity was unchanged in mesh-implanted wild-type mice, but was significantly increased in NOS2(-/-) mice (P < 0.01), due to decreased S-nitrosylation of the enzyme in these animals. We conclude that NOS2-derived NO is crucial for an adequate response to and integration of polypropylene mesh implants in the peritoneum. NO deficiency results in a prolonged inflammatory reaction to the mesh implant, and reduced collagen deposition may contribute to an increased incidence of visceral adhesions. (C) 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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We study isoparametric submanifolds of rank at least two in a separable Hilbert space, which are known to be homogeneous by the main result in [E. Heintze and X. Liu, Ann. of Math. (2), 149 (1999), 149-181], and with such a submanifold M and a point x in M we associate a canonical homogeneous structure I" (x) (a certain bilinear map defined on a subspace of T (x) M x T (x) M). We prove that I" (x) , together with the second fundamental form alpha (x) , encodes all the information about M, and we deduce from this the rigidity result that M is completely determined by alpha (x) and (Delta alpha) (x) , thereby making such submanifolds accessible to classification. As an essential step, we show that the one-parameter groups of isometries constructed in [E. Heintze and X. Liu, Ann. of Math. (2), 149 (1999), 149-181] to prove their homogeneity induce smooth and hence everywhere defined Killing fields, implying the continuity of I" (this result also seems to close a gap in [U. Christ, J. Differential Geom., 62 (2002), 1-15]). Here an important tool is the introduction of affine root systems of isoparametric submanifolds.
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Object. The aim of this study was to describe the surgical anatomy of the mediobasal aspect of the temporal lobe and the supracerebellar transtentorial (SCTT) approach performed not with an opening, but with the resection of the tentorium, as an alternative route for the neurosurgical management of vascular and tumoral lesions arising from this region. Methods. Cadaveric specimens were used to illustrate the surgical anatomy of the mediobasal region of the temporal lobe. Demographic aspects, characteristics of lesions, clinical presentation, surgical results, follow-up findings, and outcomes were retrospectively reviewed for patients referred to receive the SCTT approach with tentorial resection. Results. Ten patients (83%) were female and 2 (17%) were male. Their ages ranged from 6 to 59 years (mean 34.5 +/- 15.8 years). All lesions (3 posterior cerebral artery aneurysms, 3 arteriovenous malformations, 3 cavernous malformations, and 3 tumors) were completely excluded or resected. After a mean follow-up period of 143 months (range 10-240 months), the mean postoperative Glasgow Outcome Scale score was 4.9. Conclusions. Knowledge of the surgical anatomy provides improvement for microsurgical approaches. The evolution from a small opening to a resection of the tentorium absolutely changed the exposure of the mediobasal aspect of the temporal lobe. The SCTT approach with tentorial resection is an excellent alternative route to the posterior part of mediobasal aspect of the temporal lobe, and it was enough to achieve the best neurosurgical management of tumoral and vascular lesions located in this area. (http://thejns.org/doi/abs/10.3171/2011.12.JNS111256)
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One drawback of in vitro cell culturing is the dedifferentiation process that cells experience. Smooth muscle cells (SMC) also change molecularly and morphologically with long term culture. The main objective of this study was to evaluate if culture passages interfere in vascular SMC mechanical behavior. SMC were obtained from five different porcine arterial beds. Optical magnetic twisting cytometry (OMTC) was used to characterize mechanically vascular SMC from different cultures in distinct passages and confocal microscopy/western blotting, to evaluate cytoskeleton and extracellular matrix proteins. We found that vascular SMC rigidity or viscoelastic complex modulus (G) decreases with progression of passages. A statistically significant negative correlation between G and passage was found in four of our five cultures studied. Phalloidin-stained SMC from higher passages exhibited lower mean signal intensity per cell (confocal microscopy) and quantitative western blotting analysis showed a decrease in collagen I content throughout passages. We concluded that vascular SMC progressively lose their stiffness with serial culture passaging. Thus, limiting the number of passages is essential for any experiment measuring viscoelastic properties of SMC in culture.
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Fluctuation-dissipation theorems can be used to predict characteristics of noise from characteristics of the macroscopic response of a system. In the case of gene networks, feedback control determines the "network rigidity," defined as resistance to slow external changes. We propose an effective Fokker-Planck equation that relates gene expression noise to topology and to time scales of the gene network. We distinguish between two situations referred to as normal and inverted time hierarchies. The noise can be buffered by network feedback in the first situation, whereas it can be topology independent in the latter.
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BACKGROUND: Posttraumatic knee stiffness is a very debilitating condition. Judet's quadricepsplasty technique has been used for more than 50 years. However, few reports of quadricepsplasty results exist in the literature. METHODS: We report the results of 45 cases of posttraumatic arthrofibrosis of the knee treated with Judet's quadricepsplasty. The results of the procedure were analyzed by measuring the degrees of flexion of the operated knees at different time points (before, immediately after, and late postoperatively). RESULTS: The degree of flexion increased from 33.6 degrees (range, 5-80 degrees) preoperatively to 105 degrees (range, 45-160 degrees) immediately after surgery, followed by a slight fall in the range of motion (ROM) in the late postoperative period, which reached an average of 84.8 degrees. There was no significant correlation between knee strength and the patient's gender, but there was a slight trend of lower strength with age. Although Judet's quadricepsplasty technique dates from more than 50 years ago, it still provides good outcomes in the treatment of rigid knees of various etiologies. In general, all cases showed the same pattern of a small decrease in the ROM in the late postoperative period. CONCLUSION: Judet's quadricepsplasty can increase the ROM of rigid knees. The ROM obtained with the surgery persists long term. (J Trauma. 2012; 72: E77-E80. Copyright (C) 2012 by Lippincott Williams & Wilkins)
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Since instrumentation of the apical foramen has been suggested for cleaning and disinfection of the cemental canal, selection of the file size and position of the apical foramen have challenging steps. This study analyzed the influence of apical foramen lateral opening and file size can exert on cemental canal instrumentation. Thirty-four human maxillary central incisors were divided in two groups: Group 1 (n=17), without flaring, and Group 2 (n=17), with flaring with LA Axxess burs. K-files of increasing diameters were progressively inserted into the canal until binding at the apical foramen was achieved and tips were visible and bonded with ethyl cyanoacrylate adhesive. Roots/files set were cross-sectioned 5 mm from the apex. Apices were examined by scanning electron microscopy at ×140 and digital images were captured. Data were analyzed statistically by Student’s t test and Fisher’s exact test at 5% significance level. SEM micrographs showed that 19 (56%) apical foramina emerged laterally to the root apex, whereas 15 (44%) coincided with it. Significantly more difficulty to reach the apical foramen was noted in Group 2. Results suggest that the larger the foraminal file size, the more difficult the apical foramen instrumentation may be in laterally emerged cemental canals.
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The role played by human activity in coastline changes indicates a general tendency of retreating coasts, especially deltaic environments, as a result of the recent trend of sea level rise as well as the blockage of the transfer of sediments towards the coast, especially due to the construction of dams. This is particularly important in deltaic environments which are suffering a dramatic loss of area in the last decades. In contrast, in this paper, we report the origin and evolution of an anthropogenic delta, the Valo Grande delta, on the south-eastern Brazilian coast, whose origin is related to the opening of an artificial channel and the diversion of the main flow of the Ribeira de Iguape River. The methodology included the analysis of coastline changes, bathymetry and coring, which was used to determine the sedimentation rates and grain-size changes over time. The results allowed us to recognize the different facies of the anthropogenic delta and to establish its lateral and vertical depositional trends. Despite not being very frequent, anthropogenic deltas represent a favorable environment for the record of natural and anthropogenic changes in historical times and, thus, deserve more attention from researchers of different subjects
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We find conditions for two piecewise 'C POT.2+V' homeomorphisms f and g of the circle to be 'C POT.1' conjugate. Besides the restrictions on the combinatorics of the maps (we assume that the maps have bounded combinatorics), and necessary conditions on the one-side derivatives of points where f and g are not differentiable, we also assume zero mean-nonlinearity for f and g.
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[EN]The meccano method is a novel and promising mesh generation method for simultaneously creating adaptive tetrahedral meshes and volume parametrizations of a complex solid. We highlight the fact that the method requires minimum user intervention and has a low computational cost. The method builds a 3-D triangulation of the solid as a deformation of an appropriate tetrahedral mesh of the meccano. The new mesh generator combines an automatic parametrization of surface triangulations, a local refinement algorithm for 3-D nested triangulations and a simultaneous untangling and smoothing procedure. At present, the procedure is fully automatic for a genus-zero solid. In this case, the meccano can be a single cube. The efficiency of the proposed technique is shown with several applications...
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[EN]The meccano method is a novel and promising mesh generation technique for simultaneously creating adaptive tetrahedral meshes and volume parameterizations of a complex solid. The method combines several former procedures: a mapping from the meccano boundary to the solid surface, a 3-D local refinement algorithm and a simultaneous mesh untangling and smoothing. In this paper we present the main advantages of our method against other standard mesh generation techniques. We show that our method constructs meshes that can be locally refined by using the Kossaczky bisection rule and maintaining a high mesh quality. Finally, we generate volume T-mesh for isogeometric analysis, based on the volume parameterization obtained by the method…