bluuebunny/crossref_metadata_2025_split huggingface dataset:
Die Musen Im Dienste Christi: Strategien Der Rechtfertigung Christlicher Dichtung in Der Lateinischen Spätantike
Authors: Gärtner Thomas 
Published: December 2004

AbstractThe present article examines the arguments by which early Christian poets in Late Antiquity justify their attempt to combine Christian content and pagan poetical form. It focuses on the poetologically significant parts of their works, especially the proems. Whereas the earliest poets, i.e.Proba, Prudentius and Orientius, justify Christian poetry by its effects on the poet's personality and in the context of the poet's life, Juvencus prefigures another type of argument which is fully developed in Sedulius' Carmen paschale, according to which Christian poetry is justified by its material and formal qualities. This new type of argument has enormous reception in the Middle Ages and is especially adapted by Hrotsvith of Gandersheim who combines content and form as two coordinates of a more differentiated system.
Motion Estimation from Image and Inertial Measurements
Authors: Strelow Dennis , Singh Sanjiv 
Published: December 2004

Cameras and inertial sensors are each good candidates for autonomous vehicle navigation, modeling from video, and other applications that require six-degrees-of-freedom motion estimation. However, these sensors are also good candidates to be deployed together, since each can be used to resolve the ambiguities in estimated motion that result from using the other modality alone. In this paper, we consider the specific problem of estimating sensor motion and other unknowns from image, gyro, and accelerometer measurements, in environments without known fiducials. This paper targets applications where external positions references such as global positioning are not available, and focuses on the use of small and inexpensive inertial sensors, for applications where weight and cost requirements preclude the use of precision inertial navigation systems. We present two algorithms for estimating sensor motion from image and inertial measurements. The first algorithm is a batch method, which produces estimates of the sensor motion, scene structure, and other unknowns using measurements from the entire observation sequence simultaneously. The second algorithm recovers sensor motion, scene structure, and other parameters recursively, and is suitable for use with long or “infinite” sequences, in which no feature is always visible. We evaluate the accuracy of the algorithms and their sensitivity to their estimation parameters using a sequence of four experiments. These experiments focus on cases where estimates from image or inertial measurements alone are poor, on the relative advantage of using inertial measurements and omni directional images, and on long sequences in which the percentage of the image sequence in which individual features are visible is low.
Design of Zone Tariff Systems in Public Transportation
Authors: Hamacher Horst W. , Schöbel Anita 
Published: December 2004

Dedicated to our doctor father and grandfather, Prof. Dr. E. Rainer Burkard, on the occasion of his 60th birthday Given a public transportation system represented by its stops and direct connections between stops, we present OR models for two problems dealing with the prices for the customers. In the first, the fare problem, subsets of stops are already aggregated to zones and “good” tariffs have to be found in the existing zone system. Closed form solutions for the fare problem are presented for three objective functions. The second problem, the zone problem includes the design of the zones. In an exemplary way we study this problem for one of the objectives. It is NP hard and we therefore propose three heuristics which prove to be very successful in the redesign of one of Germany's transportation systems.
A Diffusion Approximation for the G/GI/n/m Queue
Authors: Whitt Ward 
Published: December 2004

We develop a diffusion approximation for the queue-length stochastic process in the G/GI/n/m queueing model (having a general arrival process, independent and identically distributed service times with a general distribution, n servers, and m extra waiting spaces). We use the steady-state distribution of that diffusion process to obtain approximations for steady-state performance measures of the queueing model, focusing especially upon the steady-state delay probability. The approximations are based on heavy-traffic limits in which n tends to infinity as the traffic intensity increases. Thus, the approximations are intended for large n. For the GI/M/n/∞ special case, Halfin and Whitt (1981) showed that scaled versions of the queue-length process converge to a diffusion process when the traffic intensity ρn approaches 1 with (1 – ρn)√n → β for 0 < β < ∞. A companion paper, Whitt (2005), extends that limit to a special class of G/GI/n/mn models in which the number of waiting places depends on n and the service-time distribution is a mixture of an exponential distribution with probability p and a unit point mass at 0 with probability 1 – p. Finite waiting rooms are treated by incorporating the additional limit mn/√n → κ for 0 < κ ≤ ∞. The approximation for the more general G/GI/n/m model developed here is consistent with those heavy-traffic limits. Heavy-traffic limits for the GI/PH/n/∞ model with phase-type service-time distributions established by Puhalskii and Reiman (2000) imply that our approximating process is not asymptotically correct for nonexponential phase-type service-time distributions, but nevertheless, the heuristic diffusion approximation developed here yields useful approximations for key performance measures such as the steady-state delay probability. The accuracy is confirmed by making comparisons with exact numerical results and simulations.
On the Stability of Supply Chains
Authors: Daganzo Carlos F. 
Published: December 2004

This paper examines the stability of decentralized, multistage supply chains under arbitrary demand conditions. It looks for intrinsic properties of the inventory replenishment policies that hold for all customer demand processes and for policies with desirable properties. It is found that the overall conditions experienced by suppliers several stages removed from the final customer, e.g., the variances of the orders they receive and the inventories they keep, depend on the policy much more than on the demand process. A policy-specific but demand-independent upper bound for the order variance amplification factor of any decentralized policy is shown to exist, and its formula is presented. The bound is always tight for the suppliers at the end of a long chain so that a policy exhibits the “bullwhip effect” if and only if its bound is greater than 1. A simple necessary condition for bullwhip avoidance is also identified in terms of a policy's “gain.” Gain is the marginal change in average inventory induced by a policy when there is a small but sustained change in the demand rate. It is shown that all policies with positive gain produce the bullwhip effect if they do not use future order commitments. Because manufacturers can reduce costs by operating with positive gain, this explains the prevalence of the bullwhip effect. A family of commitment-based policies that can dynamically maintain any desired inventory level for any demand rate (e.g., achieve positive gain) without the bullwhip effect is also presented. The family includes just-in-time strategies as a special case. Simulation results are used as an illustration.
A General Equilibrium Model for Industries with Price and Service Competition
Authors: Bernstein Fernando , Federgruen Awi 
Published: December 2004

This paper develops a stochastic general equilibrium inventory model for an oligopoly, in which all inventory constraint parameters are endogenously determined. We propose several systems of demand processes whose distributions are functions of all retailers' prices and all retailers' service levels. We proceed with the investigation of the equilibrium behavior of infinite-horizon models for industries facing this type of generalized competition, under demand uncertainty. We systematically consider the following three competition scenarios. (1) Price competition only: Here, we assume that the firms' service levels are exogenously chosen, but characterize how the price and inventory strategy equilibrium vary with the chosen service levels. (2) Simultaneous price and service-level competition: Here, each of the firms simultaneously chooses a service level and a combined price and inventory strategy. (3) Two-stage competition: The firms make their competitive choices sequentially. In a first stage, all firms simultaneously choose a service level; in a second stage, the firms simultaneously choose a combined pricing and inventory strategy with full knowledge of the service levels selected by all competitors. We show that in all of the above settings a Nash equilibrium of infinite-horizon stationary strategies exists and that it is of a simple structure, provided a Nash equilibrium exists in a so-called reduced game. We pay particular attention to the question of whether a firm can choose its service level on the basis of its own (input) characteristics (i.e., its cost parameters and demand function) only. We also investigate under which of the demand models a firm, under simultaneous competition, responds to a change in the exogenously specified characteristics of the various competitors by either: (i) adjusting its service level and price in the same direction, thereby compensating for price increases (decreases) by offering improved (inferior) service, or (ii) adjusting them in opposite directions, thereby simultaneously offering better or worse prices and service.
Fairness and Transaction Costs: The Contribution of Organizational Justice Theory to an Integrative Model of Economic Organization
Authors: Husted Bryan W. , Folger Robert 
Published: December 2004

In this article, we begin to integrate two fields that have, until now, remained largely independent of one another: organizational justice and transaction-cost economics. Transaction costs consist of search, bargaining, monitoring, enforcement, and other costs not directly related to the production of goods or services. Usually such costs are attributed to difficulties in measurement (the metering problem) or difficulties in redeploying assets to alternative uses (asset specificity). These variables are thought to be objective features of economic transactions. Rarely are the social-psychological dimensions of these objective features taken into account. Although economic transactions are fundamentally human activities, human behavior in the economics literature is usually reduced to such simplifying assumptions as shirking and bounded rationality. In this article, we develop a model of transaction costs based on a more complete description of human psychology as it operates in exchange relationships.We argue that transaction costs are often due to the difficulty of evaluating the fairness of a specific exchange of goods and services. Besides asset specificity and the metering problem, which are treated in the transaction-cost economics literature, the organizational justice literature is especially relevant. Beginning with the work of Ouchi (1980), the paper examines some of the ways that the organizational justice literature complements transaction-cost economics. Because mechanisms that order economic transactions are essentially conflict-resolution structures, we develop a model of economic organization in which transaction costs are related to the perception of fairness in economic exchange. In the literature, governance mechanisms are selected so as to minimize transaction costs. Based on the organizational justice framework, we suggest that the transaction-cost calculus is affected by the perception of fairness in the exchange. In addition, the relationship between the governance mechanism and the perception of fairness is moderated by the elements of interactional justice that characterize the exchange.
Effect of Dietary Lipid Level on Growth Performance of Splittail at 18°C
Authors: Deng Dong-Fang , Teh Swee J , Min Tae-Sun , Hung Silas S O 
Published: December 2004

Abstract
A 12-week feeding trial was conducted to study the effect of dietary lipid level on growth performance of juvenile Sacramento splittail Pogonichthys macrolepidotus at 18°C. We selected this temperature to simulate their natural habitats, although an earlier study showed that their optimum temperature was 22–26°C. Six isonitrogenous and isoenergetic purified diets were formulated to contain 2–12% lipid in 2% increments, and dietary lipid was an equal mix of corn oil and cod liver oil. Fish with an average initial body weigh of 9.0 ± 0.2 g (mean ± SE, n = 24) were kept in a 24-tank, flow-through system with 15 fish per tank, and each diet was randomly assigned to four replicate tanks of fish. Fish were fed 3.0% of their body weight per day by automatic feeders, which dispensed a small amount of feed every few minutes in daylight hours. Body weight and feed efficiency increased significantly with increasing dietary lipid level up to 8%. Fish fed the diet containing 8% lipid showed significantly higher body weight increase and feed efficiency than those fed the diets containing less than 6% lipid. Dietary lipid level did not affect the hepatosomatic index, condition factor, and intraperitoneal fat ratio. Whole-body moisture was significantly lower but lipid was higher in fish fed the diet containing 8% lipid than in those fed the diets containing less than 6% lipid. Histological analysis revealed a higher prevalence of hepatocellular fatty vacuolation in fish fed the diet containing 12% lipid. Based on a broken-line analysis, a dietary lipid level of 8.4% is recommended for juvenile splittail reared at 18°C.
The role of stroma in prostatic carcinogenesis
Authors: Grossfeld G D , Hayward S W , Tlsty T D , Cunha G R 
Published: December 2004

Abstract
Most human prostate tumors are adenocarcinomas which arise from the epithelial cells that line the glands and ducts of the prostate. Consequently, the malignant epithelial cell, or more specifically genetic damage suffered by that malignant epithelial cell, has been the major focus of prostate cancer research to date. There is, however, increasing evidence to suggest that alterations in the stromal microenvironment associated with a malignant epithelium may be necessary for progression of carcinogenesis.
We have recently hypothesized that interactions between the stroma and epithelium become altered as a result of genetic damage to the prostatic epithelial cell. During prostatic carcinogenesis, this abnormal signaling may lead to changes in both the prostatic epithelium and smooth muscle with concomitant loss of growth control. In this way, both a malignant epithelium and an abnormal or ‘tumor stroma’ evolve.
The purpose of this article is to describe interactions between the stroma and epithelium of the normal prostate, and then to summarize evidence suggesting that stromal cells derived from benign versus malignant sources may exert differential effects on epithelial cell growth and differentiation.
Acknowledgements
This work was supported by NIH grants DK52721, CA 59831, DK 45861, CA 64872, DK 52708 and DK 47517, and by an AFUD/Pfizer USPG Research Scholarship to GDG.
Cardiac metastasis from primary anaplastic thyroid carcinoma: report of three cases and a review of the literature.
Authors: Giuffrida D , Gharib H 
Published: December 2004

BACKGROUNDClinically evident cardiac metastases from malignant neoplasms are uncommon. The frequency of thyroid metastasis to the heart is very low. To our knowledge, over the last 20 years only a few cases have been reported in the entire literature. Metastatic cardiac involvement occurs most often during the terminal stage.PATIENTSWe present three cases of anaplastic thyroid cancer with metastatic involvement of the heart.RESULTSTwo of the patients died from cardiac problems. The absence of early symptoms makes the clinical diagnosis of metastatic carcinoma difficult.CONCLUSIONSAnaplastic thyroid cancer is an aggressive cancer with a dismal prognosis. It should be borne in mind as a source of cardiac metastasis and a cause of cardiac death.
Dexamethasone modulates insulin receptor expression and subcellular distribution of the glucose transporter GLUT 1 in UMR 106-01, a clonal osteogenic sarcoma cell line
Authors: Thomas D M , Rogers S D , Ng K W , Best J D 
Published: December 2004

ABSTRACT
Corticosteroids have profound effects on bone metabolism, though the underlying mechanisms remain unclear. They are also known to alter glucose metabolism, in part by induction of insulin resistance. To determine whether corticosteroids impair glucose metabolism in bone cells, we have examined the actions of dexamethasone (DEX) on glucose transport and insulin receptor expression using osteoblast-like UMR 106-01 cells. DEX was shown to inhibit basal 2-deoxyglucose uptake by up to 30% in a time- and dose-dependent manner. It inhibited insulin-stimulated glucose transport by 13%. By Northern and Western blot analysis, DEX was shown to stimulate insulin receptor mRNA and protein by up to 5·6-fold, but it had no effect on expression of the glucose transporter GLUT 1 mRNA or protein under basal conditions. However, DEX augmented insulin-stimulated GLUT 1 mRNA and protein levels. By Scatchard analysis of labelled insulin binding, DEX increased insulin receptor number per cell by 54%. Subcellular fractionation and Western blot analysis demonstrated that DEX caused a redistribution of immunoreactive GLUT 1 from plasma membrane to intracellular microsomes, resulting in a 21% decrease in GLUT 1 at the plasma membrane. These data suggest that (i) DEX impairs basal glucose transport by post-translational mechanisms in UMR 106-01 cells, (ii) DEX increases insulin receptor mRNA, protein and insulin binding and (iii) the inhibition of glucose transport by DEX dominates its effects on the insulin receptor. It is possible that DEX inhibition of glucose transport in osteoblasts may contribute to steroid-induced osteoporosis.
Expression of activin βC subunit mRNA in reproductive tissues
Authors: Loveland K L , McFarlane J R , de Kretser D M 
Published: December 2004

ABSTRACT
A cDNA encoding the potential activin βC subunit was produced from human testis RNA using reverse transcription and PCR and then used as a probe in Northern blot analysis of poly(A)+ RNA. A transcript of ∼1·8 kb was evident in human ovary, placenta and testis samples. A transcript of this size was also detected in adult rat caput and cauda epididymis, and adult and day-15 testis and adult spleen, while adult liver contained a single transcript of ∼2·1 kb. Poly(A)+ RNA from primary spermatocytes but not from round spermatids contained the 1·8kb activin βC mRNA. These findings highlight the need for further studies to determine the physiological role(s) of activin βC in a wide variety of tissues.
Production of [3H]choline-labelled metabolites from endogenously 3H-labelled phosphatidylcholine in mouse pancreatic islets
Authors: Capito K , Hansen S E , Thams P 
Published: December 2004

ABSTRACT
The involvement of phosphatidylcholine (PC) hydrolysis in the regulation of insulin secretion was studied in mouse pancreatic islets prelabelled with [3H]choline. Phospholipase C (PLC) and phospholipase D (PLD) activities were demonstrated and also that of an enzyme that removes both fatty acids from PC and thus catalyses the production of [3H]glycerophosphorylcholine (GroPCho). After 2 min of incubation with 20 mm glucose a 35% increase in the content of [3H]GroPCho was observed in prelabelled islets, whereas the amount of [3H]lysoPC, [3H]phosphorylcholine (PCho) and [3H]choline was unaffected. After 30 min of incubation with 20 mm glucose, 0·2 mm tolbutamide, 40 mm KC1, 10 mm succinic acid monomethyl ester (SME) or 10 mm NaF, a 25-50% increase in [3H]GroPCho was observed. In the presence of 100 μm diazoxide or 35 μm RHC 80267 the glucose activation was attenuated. PLC was stimulated slightly by tolbutamide and 100 μm isoprenaline (isoproterenol), whereas SME decreased the amount of [3H]PCho by 10%. [3H]Choline content was increased by 25-40% in the presence of 0·16 μm 12-O-tetradecanoylphorbol 13-acetate (TPA), 10 mm NaF or 100 μm carbachol. This effect of fluoride was potentiated in the presence of 20 mm glucose. It is concluded that metabolism of PC to GroPCho may be involved in the regulation of glucose-stimulated insulin secretion, and that PLD may participate in insulin secretion evoked by TPA, carbachol and fluoride.
The role of fetal parathyroid hormone-related protein in transplacental calcium transport
Authors: Tucci J , Hammond V , Senior P V , Gibson A , Beck F 
Published: December 2004

ABSTRACT
During pregnancy, a placental calcium pump maintains the fetus in a hypercalcaemic state relative to the mother, a condition which has been thought to facilitate normal development of the fetal skeleton. Based on experiments performed in the sheep, parathyroid hormone-related protein (PTHrP) has been implicated as the hormone responsible for maintaining the placental calcium pump. In the present study on mice in which the PTHrP gene has been ablated by homologous recombination, we have measured both fetal and maternal circulating total and ionised calcium levels, as well as fetal total body calcium, in order to determine whether absence of PTHrP during fetal development has an effect on fetal calcium levels. Our results show that, in fetuses lacking PTHrP, circulating ionised calcium levels are significantly lower than those of heterozygote and wild-type littermates, but circulating total calcium levels show no difference. Total body calcium levels of null mutants are significantly higher than those of normal littermates.
The role of PTHrP in maintaining the integrity of the transplacental calcium pump in the rodent thus remains unclear. It may be that the lower levels of fetal blood ionised calcium in mutant animals are due to disruption of the placental pump, but, if this is the case, compensatory mechanisms have operated to allow the excessive calcium deposition seen in the skeletons of these animals. Alternatively, the increased avidity of the bones for calcium may in itself have produced a lower equilibrium level of available ionised calcium.