A MODEL OF ENTRY-EXIT DECISIONS AND CAPACITY CHOICE UNDER DEMAND UNCERTAINTY

Many investment decisions of agribusiness firms such as when to invest in an emerging market or whether to expand the capacity of the firm involve irreversible investment and uncertainty about demand, cost or competition. This paper uses an option-value model to examine the factors affecting an agribusiness firm's decision whether and how much to invest in an emerging market under demand uncertainty. Demand uncertainty and irreversibility of investment make investment less desirable than the net present value (NPV) rule indicates. The inactive firm is more reluctant to enter the market when it takes into account demand uncertainty because it preserves the opportunity of making a better investment later. The active firm is more reluctant to abandon the investment because there is an option value of keeping the operation alive. There is a greater distance between the entry and exit thresholds under the option-value approach than under the NPV rule due to demand uncertainty. The results have implications for agribusiness decision-making to understand and respond to uncertainty.agribusiness decision-making, demand uncertainty, entry-exit decisions, net present value, real options, remote sensing, Demand and Price Analysis,

Some fixed point theorems for multi-valued mappings on partial cone metric spaces

In this paper, we study the fixed point theory for multi-valued mappings on partial cone metric spaces. We prove an analogous to the well-known Kannan$'s$ fixed point theorem and Chatterjea$'s$ fixed point theorem for multi-valued mappings on partial cone metric spaces.Comment: arXiv admin note: substantial text overlap with arXiv:2208.0679

Dieulafoy Lesion in the Stomach

Dieulafoy disease is an uncommon cause of gastrointestinal system bleeding. Although the exact cause is not known, it is characterized by bleeding from abnormal submucosal vessels. There are many methods for diagnosis and treatment. In this case, a patient with a long-time undiagnosed stomach Dieulafoy lesion had a surgical resection. During the postoperative period the patient was discharged without any complication

Neural Network Compression for Noisy Storage Devices

Compression and efficient storage of neural network (NN) parameters is critical for applications that run on resource-constrained devices. Although NN model compression has made significant progress, there has been considerably less investigation in the actual physical storage of NN parameters. Conventionally, model compression and physical storage are decoupled, as digital storage media with error correcting codes (ECCs) provide robust error-free storage. This decoupled approach is inefficient, as it forces the storage to treat each bit of the compressed model equally, and to dedicate the same amount of resources to each bit. We propose a radically different approach that: (i) employs analog memories to maximize the capacity of each memory cell, and (ii) jointly optimizes model compression and physical storage to maximize memory utility. We investigate the challenges of analog storage by studying model storage on phase change memory (PCM) arrays and develop a variety of robust coding strategies for NN model storage. We demonstrate the efficacy of our approach on MNIST, CIFAR-10 and ImageNet datasets for both existing and novel compression methods. Compared to conventional error-free digital storage, our method has the potential to reduce the memory size by one order of magnitude, without significantly compromising the stored model's accuracy.Comment: 19 pages, 9 figure

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

Genetic Variation of Juvenile Wood Properties in a Loblolly Pine Diallel Test

The reduced rotation age for loblolly pine plantations has resulted in an increased percentage of juvenile wood. Juvenile wood has lower wood density, shorter tracheid length and higher lignin content than mature wood. The increased use of juvenile wood has reduced yields and increased pulping costs for the pulp and paper industry. If significant genetic variation in juvenile wood properties can be found, breeders may be able to improve juvenile wood properties to reduce pulping losses. Genetic variation in several wood quality traits of loblolly pine (Pinus taeda L.) was investigated for 14 full-sib families generated by a 6-parent half-diallel mating design. Wood samples of 12 mm increment cores were collected from 11-year-old trees from one test site. Earlywood and latewood of ring three (juvenile wood) and ring eight (transition wood) for each increment core were analyzed for alpha cellulose content (ACY), average fiber length (FLW), coarseness (COA), and lignin content (LIG). Ring three and ring eight had significant differences in ACY, FLW, and COA, but not for LIG. Latewood of both rings had higher ACY, FLW, and COA than earlywood. Transition wood had significantly higher ACY, FLW, and COA, but lower LIG than juvenile wood. Families differed significantly for ACY, FLW, and COA, but not for LIG. In general, additive genetic effects explained greater percentages of family variation than dominance genetic effects. Genetic variation increased from juvenile to transition wood. While weak individual and family heritabilities were found for ACY, FLW, and COA for juvenile wood, heritability estimates for transition wood were moderate, indicating the potential for improving these juvenile traits.Papers and abstracts from the 27th Southern Forest Tree Improvement Conference held at Oklahoma State University in Stillwater, Oklahoma on June 24-27, 2003

Heterotopic gastrointestinal cyst mimicking chronic cholecystitis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Heterotopic gastric mucosa is described almost everywhere in the gastrointestinal tract, from the oral cavity to the rectum. The occurrence of heterotopic gastric tissue in the gallbladder is rare. A choristoma can be defined as a new growth developing from a displaced anlage not normally present in the anatomical site where it developed. We present an extremely uncommon case of a cyst (choristoma) attached to the gallbladder, which contained gastric and intestinal mucosa.</p> <p>Case presentation</p> <p>A 33-year-old woman was hospitalized with clinical symptoms of chronic cholecystitis. The laboratory findings were within the normal range. Abdominal ultrasonography revealed a thickened gallbladder wall and a stone in the cystic duct was suspected. In the course of laparoscopic cholecystectomy, a cyst was visualized in the vicinity of the duct and the gallbladder neck. Microscopic examination of the removed cyst revealed evidence of gastric, duodenal and small-intestinal mucosa. The immunohistochemical study revealed many endocrine cells, which were positive for several endocrine cell markers such as chromogranin, serotonin, gastrin and so on. It can be inferred that the observed cyst had arisen from the foregut early in the development of the gastrointestinal tract.</p> <p>Conclusion</p> <p>The presence of endocrine cells together with epithelial cells supports the hypothesis that these had developed simultaneously, and that the endocrine cells had probably supported the development of the epithelial cells by the release of hormones and growth factors. To the best of the authors' knowledge, this report is the first to report a gastrointestinal cyst choristoma with endocrine cells in the region of the cystic duct and gallbladder.</p

FAPRI 2002 World Agricultural Outlook

Crop Production/Industries, Livestock Production/Industries,