3,924 research outputs found
AGRICULTURAL MARKETS LIBERALIZATION AND THE DOHA ROUND
Using a partial equilibrium model of world agriculture, we investigate the multilateral removal of all border taxes and farm programs and their distortion of world agricultural markets. These distortions have significant terms-of-trade effects. World trade is also significantly impacted by both types of distortions. Trade expansion is substantial for most commodities, especially dairy, meats, and vegetable oils. Net agricultural and food exporters (Brazil, Australia, and Argentina) emerge with expanded exports; whereas net importing countries with limited distortions before liberalization are penalized by higher world markets prices and reduced imports. The US gains significant export shares in livestock products and imports more dairy products. Without protection and domestic subsidies, the EU loses many of its livestock and dairy export markets.Doha, Agriculture, trade liberalization, domestic policy, International Relations/Trade,
A new method in thoracoscopic inferior mediastinal lymph node biopsy: a case report
<p>Abstract</p> <p>Introduction</p> <p>We performed video-thoracoscopy with a video-mediastinoscope to conduct a mediastinal lymph node biopsy. Here, we discuss the various advantages of the method.</p> <p>Case presentation</p> <p>A 56-year-old Turkish Caucasian man had been complaining of dyspnea on exertion, hacking cough, fever and continuous sweating for one and a half months. Thoracic computed tomography revealed enlarged paratracheal and aorticopulmonary lymph nodes, the largest of which was 1 cm in diameter and reticulo-micronodular interstitial infiltration extending symmetrically to the pleural surfaces in both pulmonary perihilar areas. Computed tomography supported positron emission tomography showed increased fluorodeoxyglucose retention in lymph nodes in both hilar areas (10R and 10L) (maximum standardized uptake values 5.6 and 5.7), and in the right lower paratracheal (4R) (maximum standardized uptake value 4.1) and right para-esophageal (8) (maximum standardized uptake value 8.9) lymph nodes. Pathological examination of the right lymph node number 8 biopsy using the video-mediastinoscope revealed the presence of granulomatous inflammation. No problems were observed during the postoperative period.</p> <p>Conclusion</p> <p>The use of the video-mediastinoscope for inferior lymph node biopsy in thoracoscopy is an easy, safe and practical method, especially in patients with pleural adhesions.</p
Sparse random networks for communication-efficient federated learning
One main challenge in federated learning is the large communication cost of ex-changing weight updates from clients to the server at each round. While prior work has made great progress in compressing the weight updates through gradient compression methods, we propose a radically different approach that does not update the weights at all. Instead, our method freezes the weights at their initial random values and learns how to sparsify the random network for the best performance. To this end, the clients collaborate in training a stochastic binary mask to find the optimal sparse random network within the original one. At the end of the training, the final model is a sparse network with random weights – or a sub-network inside the dense random network. We show improvements in accuracy, communication (less than 1 bit per parameter (bpp)), convergence speed, and final model size (less than 1 bpp) over relevant baselines on MNIST, EMNIST, CIFAR- 10, and CIFAR-100 datasets, in the low bitrate regime
Volume Gains of Rooted Loblolly Pine Clones at Age 10 in Florida and Alabama
An estimate of the growth potential of clonal lines produced from elite crosses compared to trees grown from seed is needed to justify clonal forestry programs. A series of age 10 loblolly pine (Pinus taeda L.) rooted cutting tests planted in Nassau County, Florida and Monroe County, Alabama are some of the oldest clonally replicated studies in existence. A 3 X 3 factorial produced 9 cross families from which 4-6 clones were produced as rooted cuttings from seedling hedges. Clones and seedlings were planted in a randomized complete block design with split-plots for seedlings and rooted cuttings. Clone genetic values were estimated by Best Linear Unbiased Prediction method and genetic gains were estimated for various clone selection scenarios. Average volume gain over the family mean estimate by choosing the best clones from each family was 12.6%. The top clone of the 45 tested clones yielded 39.8% more volume than the grand mean. The top five and the top 10 clones had 30% and 23% more volume gain than the grand mean, respectively.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003
Variation in Estimation of Genetic Parameters from Small Disconnected Diallel Mating
Diallel mating designs are widely used in plant improvement programs to estimate additive and dominance genetic variances, and to provide a base population for advanced selection. It is very common to limit the number of parents in a diallel small (4-8) in order to keep the number of crosses in a manageable size and complete the diallel breeding within a short time period. Many such diallels are created in a breeding program, and often are disconnected. Thus there are generally large sampling errors among diallels for genetic variance components. In this study, we examined variation in estimates of variance components and heritabilities of two loblolly pine breeding populations. Over 100 diallels (105) from the Coastal breeding population and and 114 from Piedmont breeding populations were examined for the distribution of these parameters. Frequency distribution of GCA variance and narrow-sense heritability showed an approximate normal distribution, while SCA variance showed a considerable skewness and displayed a significant departure from normality. Genetic parameter estimates fluctuated considerably from one diallel to another as expected due to the effect of the small population size. Individual heritability ranged from 0.0 to 0.62 in the Coastal breeding population and from 0.0 to 0.52 in the Piedmont population. Some theoretical considerations regarding to the optimum sample size to estimate reliable genetic parameters from diallel tests were addressed.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003
Microstructural characterization and simulation of damage for geared sheet components
The evolution of damage in geared components manufactured from steel sheets was investigated, to analyse the influence of damage caused by the sheet-bulk-metal forming. Due to the inhomogeneous and multi-axial deformation in the investigated parts, different aspects such as the location-dependent shape and size of voids are analysed by means of various microscopic methods. In particular, a method to characterize the state of damage evolution, i. e. void nucleation, growth and coalescence using scanning electron microscopy (SEM) is applied. The investigations reveal a strong dependence of the void area fraction, shape of voids and thus damage evolution on the loading mode. The microstructural analysis is complemented with FEM simulations using material models which consider the characteristics of the void evolution. © Published under licence by IOP Publishing Ltd
Resuscitation and quantification of stressed Escherichia coli K12 NCTC8797 in water samples
The aim of this study was to investigate the impact on numbers of using different media for the enumeration of Escherichia coli subjected to stress, and to evaluate the use of different resuscitation methods on bacterial numbers. E. coli was subjected to heat stress by exposure to 55 °C for 1 h or to light-induced oxidative stress by exposure to artificial light for up to 8 h in the presence of methylene blue. In both cases, the bacterial counts on selective media were below the limits of detection whereas on non-selective media colonies were still produced. After resuscitation in non-selective media, using a multi-well MPN resuscitation method or resuscitation on membrane filters, the bacterial counts on selective media matched those on non-selective media. Heat and light stress can affect the ability of E. coli to grow on selective media essential for the enumeration as indicator bacteria. A resuscitation method is essential for the recovery of these stressed bacteria in order to avoid underestimation of indicator bacteria numbers in water. There was no difference in resuscitation efficiency using the membrane filter and multi-well MPN methods. This study emphasises the need to use a resuscitation method if the numbers of indicator bacteria in water samples are not to be underestimated. False-negative results in the analysis of drinking water or natural bathing waters could have profound health effects
New fixed point theorems for orthogonal -contractions in incomplete -metric spaces
In this paper, we introduce the concept of orthogonal -metric spaces and by using -contraction in orthogonal -metric spaces, we give the concept of orthogonal -contraction (briefly, -contraction) and investigate fixed point results for such mappings. Many existing results in the literature appear to be special case of results proved in this paper. An example to support our main results is also mentioned
Energy Efficiency of Distributed Environmental Control Systems
In this report, we present an analytical evaluation of the potential of occupant-regulated distributed environmental control systems (DECS) to enhance individual occupant thermal comfort in an office building with no increase, and possibly even a decrease in annual energy consumption. To this end we developed and applied several analytical models that allowed us to optimize comfort and energy consumption in partitioned office buildings equipped with either conventional central HVAC systems or occupant-regulated DECS. Our approach involved the following interrelated components: 1. Development of a simplified lumped-parameter thermal circuit model to compute the annual energy consumption. This was necessitated by the need to perform tens of thousands of optimization calculations involving different US climatic regions, and different occupant thermal preferences of a population of ~50 office occupants. Yearly transient simulations using TRNSYS, a time-dependent building energy modeling program, were run to determine the robustness of the simplified approach against time-dependent simulations. The simplified model predicts yearly energy consumption within approximately 0.6% of an equivalent transient simulation. Simulations of building energy usage were run for a wide variety of climatic regions and control scenarios, including traditional “one-size-fits-all” (OSFA) control; providing a uniform temperature to the entire building, and occupant-selected “have-it-your-way” (HIYW) control with a thermostat at each workstation. The thermal model shows that, un-optimized, DECS would lead to an increase in building energy consumption between 3-16% compared to the conventional approach depending on the climate regional and personal preferences of building occupants. Variations in building shape had little impact in the relative energy usage. 2. Development of a gradient-based optimization method to minimize energy consumption of DECS while keeping each occupant’s thermal dissatisfaction below a given threshold. The DECS energy usage was calculated using the simplified thermal model. OSFA control; providing a uniform temperature to the entire building, and occupant-selected HIYW control with a thermostat at each workstation were implemented for 3 cities representing 3 different climatic regions and control scenarios. It is shown that optimization allows DECS to deliver a higher level of individual and population thermal comfort while achieving annual energy savings between 14 and 26% compared to OSFA. The optimization model also allowed us to study the influence of the partitions’ thermal resistance and the variability of internal loads at each office. These influences didn’t make significant changes in the optimized energy consumption relative to OSFA. The results show that it is possible to provide thermal comfort for each occupant while saving energy compared to OSFA Furthermore, to simplify the implementation of this approach, a fuzzy logic system has been developed to generalize the overall optimization strategy. Its performance was almost as good as the gradient system. The fuzzy system provided thermal comfort to each occupant and saved energy compared to OSFA. The energy savings of the fuzzy system were not as high as for the gradient-optimized system, but the fuzzy system avoided complete connectivity, and the optimization did not have to be repeated for each population. 3. We employed a detailed CFD model of adjacent occupied cubicles to extend the thermal-circuit model in three significant ways: (a) relax the “office wall” requirement by allowing energy to flow between zones via advection as well as conduction, (b) improve the comfort model to account both for radiation as well as convection heat transfer, and (c) support ventilation systems in which the temperature is stratified, such as in underfloor air distribution systems. Initially, three-dimensional CFD simulations of several cubicle configurations, with an adjoining corridor, were performed both to understand the advection between cubicles and the resulting temperature stratification. These simulations showed that the advective flow between cubicles is very significant and severely limits the occupants’ ability to control the personal micro-environments by simply controlling the temperature of the incoming air. Subsequently, the existing thermal-circuit model was extended to include the phenomena described above. The modifications to the thermal-circuit model, which were incorporated such that the simulation time was only slightly impacted, showed that accounting for room stratification resulting from the use of floor swirl diffusers could lead to 10%-26% reduction in the annual energy consumed for HVAC in non-temperate climates. This trend was evident in both OSFA and HIYW scenarios. However, the ratio of energy usage in the two scenarios was little affected by the enhancements in the thermal model
Fourth-Year Results from a Clonal Test of Loblolly Pine
In November and December 1998, two experimental plantings were established using rooted cuttings from 450 clones of eight unrelated full-sib families of loblolly pine (Pinus taeda L.). Clones from four of the families (282 clones) were planted in South Carolina and clones from the other four families in Florida (168 clones). Both tests were laid out as randomized complete blocks with nine blocks and one ramet/clone/block. Height, survival and rust resistance were measured annually and diameter was measured at age four. Best Linear Unbiased Prediction of clone genetic values were estimated for height and volume at age four. Estimated genetic gains from various clone selection strategies, the effect of increasing or decreasing the number of ramets for testing on genetic gain, height age-age and trait-trait genetic correlations were estimated. Estimated genetic gain was highly sensitive to the intensity of clonal selection. Selecting the single best clone from each test resulted in an estimated gain of 13% (SC) and 14% (FL) in height at age four over the test average (all the clones). The single best clone from each family at each site (four in total) resulted in an estimated gain of 10% (SC) and 10% (FL). However, if six clones were selected from each family (twenty-four in total), gain was reduced to 8% (SC) and 6% (FL) in height. The genetic correlations between height at age one and height at age four were low (0.60 at SC, 0.58 at FL), but increased to 0.96 (SC) and 0.97 (FL) between heights at ages three and four. Simulations using test parameters showed that estimated gain increased with the number of ramets tested up until ten ramets per clone, but did not increase appreciably with ramet numbers above ten. Moreover, approximately 90% of the gain could be obtained using only six ramets. These data, additional details and the implications of these results will be discussed.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003
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