Modeling Differentiated Quality Standards in the Agri-Food Sector: The Case of Meat Trade in the EU

This paper looks at trade impacts of quality related standards from the supply side of the exporting country. We argue that food quality standards imposed by an importing country have profound effects on the market structure of the exporting industry, and hence a significant impact on the supply response. For our analysis, we develop a stylized oligopoly model that allows for the co-existence of complying and non-complying suppliers. The model is applied to two alternative policy options to explore different mechanisms an importing county may use to enhance the quality of its imports. We take the Polish meat sector as an empirical example, since after Poland's accession to the EU the tight EU food quality standards indeed apply but the process of adjusting to them is far from complete - particularly in Polish meat production/processing. The simulations show that a subsidy scheme, such as the EU's SAPARD program in Poland, can be an effective instrument to promote the compliance with standards and to upgrade the industry in the exporting country.food quality standards, trade, market structure, Poland, meat sector, oligopoly, International Relations/Trade, Livestock Production/Industries, Q17, Q18, L1,

Search for mixing of D0 and its antiparticle using neural networks

Mixing is a process in which a particle spontaneously turns into its antiparticle. The Standard Model of particle physics at the box diagram level predicts that mixing of a D0 should occur approximately once every ten billion decays, while other theories predict much larger mixing rates. Measurement of the mixing rate of the D0 is an important test of the Standard Model. If mixing rates are larger than what the Standard Model predicts, this could be evidence of physics beyond the Standard Model and would be a major physics discovery. Since the D0 has zero electric charge and a lifetime of only 4×10-13 seconds, limitations in current elementary particle detector technology require examination of the decay products of the D0. Some other processes have decay products that are similar to the decay products resulting from the mixing of a D0, so it is necessary to distinguish these processes. In this analysis neural networks are used to help determine whether a D0 decay involved mixing or another process. Neural networks are models of complicated functions that, given a number of inputs, will attempt to predict the value of one or more outputs. In this study, the inputs consist of observables measured by the BaBar detector at the Stanford Linear Accelerator Center. The neural network output is binary, with 1 representing the signal candidates and 0 representing all background events. The signal mode is a D0 decaying into K+, an electron, and an antineutrino, while the D0 normally decays into K-, a positron, and a neutrino. In this study we use the neural network computer program MLPfit. MLPfit requires training data which is used to develop the neural network. This training data consists of inputs that are known to produce a certain output. These neural networks were trained with MLPfit using Monte Carlo simulation data from the BaBar experiment. The goal is to produce a neural network that will provide a cleaner data sample with fewer background events than the neural network that is currently being used in the experiment. Comparisons show neural networks trained by MLPfit are comparable to the neural network that is currently being used in the experiment. Advisor: Richard D. KassSigma XiArts and Sciences Undergraduate Research Scholarshi

A Review of Educational Balance and its Relationship to the Daily Schedule in Eighteen Seventh-day Adventist Residence Academies in the United States

Problem. Within the time constraints of the 24-hour day and the sevenday week, and under the pressure of the increased number of units to be earned before graduation from Seventh-day Adventist (SDA) residence academies, it was doubtful that students were experiencing educational balance. The number of and time for activities in which a student could be engaged, plus the content and emphasis on daily functions, were studied and reported under five areas of educational balance: academic achievement, vocational and professional interests, social growth, physical activities, and religious experience. Method. Representing grades ten, eleven, and twelve in 18 out of 36 SDA residence academies in the Unifed States, 1,997 students completed a pilot-tested questionnaire consisting of 99 items; 55 administrators from these schools selected time provisions for 27 student activities; and the principals completed a short questionnaire designed to give demographic information for their schools. Responses from students were scored using a panel-prescribed weighting schedule and percentages calculated for each reply. These scores were used as possible indicators of educational balance. Results. In academic achievement, social growth, and religious experience the students rated above the mean ideal expectancy for educational balance. In physical activities the students rated slightly above this mean, but in vocational and professional interests the rating was slightly below the mean ideal expectancy. Time provisions for daily student activities exceeded the 24-hour day time limit, a constraint that had to be removed to insure educational balance. To accomplish this goal seven of the 24 total activities were placed into a variable category to be set by advisors, counselors, and work coordinators, according to individual student academic and work needs. Conclusions. Teachers were perhaps responsible for requiring their students to think, the depth depending on the students; for allowing, as opposed to requiring, their students to get everything done on time; and for encouraging temperance and good posture. Students chose to pay tithe and to make prayer a part of their daily life, two actions probably reinforced by tangible results promised by God. Student desires may have conflicted with time-limited activities such as increased study load and work. Students may have been guilty of time robbery, causing inability to meet with the guidance counselor and lack of devotional time. Time adjustments for student activities were shown to be necessary, complicated, and delicately interrelated to prevent imbalance from occurring

10 years after Kannisto: further evidence for mortality decline at advanced ages in developed countries

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The temperature dependent bandstructure of a ferromagnetic semiconductor film

The electronic quasiparticle spectrum of a ferromagnetic film is investigated within the framework of the s-f model. Starting from the exact solvable case of a single electron in an otherwise empty conduction band being exchange coupled to a ferromagnetically saturated localized spin system we extend the theory to finite temperatures. Our approach is a moment-conserving decoupling procedure for suitable defined Green functions. The theory for finite temperatures evolves continuously from the exact limiting case. The restriction to zero conduction band occupation may be regarded as a proper model description for ferromagnetic semiconductors like EuO and EuS. Evaluating the theory for a simple cubic film cut parallel to the (100) crystal plane, we find some marked correlation effects which depend on the spin of the test electron, on the exchange coupling, and on the temperature of the local-moment system.Comment: 11 pages, 9 figure

Analysis of a turbine rotor containing a transverse crack at Oak Creek Unit 17

Transient increases in one, two and three per revolution vibration characteristics of a low pressure steam turbine were observed during steam temperature reduction operations. Vibration and fracture mechanics analyses suggested the presence of a transverse shaft crack which was eventually identified by ultrasonic inspection and confirmed by destructive sectioning. Signature analyses of vibration data recorded over a two-year period prior to crack identification are correlated with fatigue crack growth, which occurred intermittently during transient temperature decreases. The apparent increased response of the rotor to vibration is due to asymmetric stiffness changes introduced by the growing transverse crack. The vibration response is predicted to increase with increasing crack depths in excess of 10% of the shaft diameter. Fracture mechanics analyses predict that fatigue crack growth occurred during periods of steam temperature decrease, when high surface tensile stresses are present. These same transient thermal stresses are shown to have retarded and prevented subsequent fatigue crack growth during steady operation

Modelling the atmosphere of the carbon-rich Mira RU Vir

Context. We study the atmosphere of the carbon-rich Mira RU Vir using the mid-infrared high spatial resolution interferometric observations from VLTI/MIDI. Aims. The aim of this work is to analyse the atmosphere of the carbon-rich Mira RU Vir, with state of the art models, in this way deepening the knowledge of the dynamic processes at work in carbon-rich Miras. Methods. We compare spectro-photometric and interferometric measurements of this carbon-rich Mira AGB star, with the predictions of different kinds of modelling approaches (hydrostatic model atmospheres plus MOD-More Of Dusty, self-consistent dynamic model atmospheres). A geometric model fitting tool is used for a first interpretation of the interferometric data. Results. The results show that a joint use of different kind of observations (photometry, spectroscopy, interferometry) is essential to shed light on the structure of the atmosphere of a carbon-rich Mira. The dynamic model atmospheres fit well the ISO spectrum in the wavelength range {\lambda} = [2.9, 25.0] {\mu}m. Nevertheless, a discrepancy is noticeable both in the SED (visible), and in the visibilities (shape and level). A possible explanation are intra-/inter-cycle variations in the dynamic model atmospheres as well as in the observations. The presence of a companion star and/or a disk or a decrease of mass loss within the last few hundred years cannot be excluded but are considered unlikely.Comment: 15 pages. Accepted in A&

Recent advances in minimally invasive colorectal cancer surgery

Laparoscopy has improved surgical treatment of various diseases due to its limited surgical trauma and has developed as an interesting therapeutic alternative for the resection of colorectal cancer. Despite numerous clinical advantages (faster recovery, less pain, fewer wound and systemic complications, faster return to work) the laparoscopic approach to colorectal cancer therapy has also resulted in unusual complications, i.e. ureteral and bladder injury which are rarely observed with open laparotomy. Moreover, pneumothorax, cardiac arrhythmia, impaired venous return, venous thrombosis as well as peripheral nerve injury have been associated with the increased intraabdominal pressure as well as patient's positioning during surgery. Furthermore, undetected small bowel injury caused by the grasping or cauterizing instruments may occur with laparoscopic surgery. In contrast to procedures performed for nonmalignant conditions, the benefits of laparoscopic resection of colorectal cancer must be weighed against the potential for poorer long-term outcomes of cancer patients that still has not been completely ruled out. In laparoscopic colorectal cancer surgery, several important cancer control issues still are being evaluated, i.e. the extent of lymph node dissection, tumor implantation at port sites, adequacy of intraperitoneal staging as well as the distance between tumor site and resection margins. For the time being it can be assumed that there is no significant difference in lymph node harvest between laparoscopic and open colorectal cancer surgery if oncological principles of resection are followed. As far as the issue of port site recurrence is concerned, it appears to be less prevalent than first thought (range 0-2.5%), and the incidence apparently corresponds with wound recurrence rates observed after open procedures. Short-term (3-5 years) survival rates have been published by a number of investigators, and survival rates after laparoscopic surgery appears to compare well with data collected after conventional surgery for colorectal cancer. However, long-term results of prospective randomized trials are not available. The data published so far indicate that the oncological results of laparoscopic surgery compare well with the results of the conventional open approach. Nonetheless, the limited information available from prospective studies leads us to propose that minimally invasive surgery for colorectal cancer surgery should only be performed within prospective trials

Computer-aided space shuttle orbiter wing design study

An analytical and experimental investigation has been made to provide a space shuttle orbiter wing design that met the guideline requirements of landing performance, stability, and hypersonic trim for a specified center-of-gravity envelope. The analytical study was facilitated by the use of the Optimal Design Integration system (ODIN) and the experimental part of the investigation was conducted in the Langley low-turbulence pressure tunnel and the Langley continuous-flow hypersonic tunnel