Auctions of licences and market structure

This paper studies sequential auctions of licences to operate in amarket where those firms that obtain at least one licence then engage ina symmetric market game. I employ a new refinement of Nash equilibrium,the concept of {\sl Markovian recursively undominated equilibrium}.The unique solution satisfies the following properties: (i) when severalfirms own licences before the auction (incumbents), new entrants buylicences in each stage, and (ii) when there is no more than one incumbent,either the single firm preempts entry altogether or entry occurs inevery stage, depending on the parameter configuration.

A two-mean reverting-factor model of the term structure of interest rates

This paper presents a two--factor model of the term structure ofinterest rates. We assume that default free discount bond prices aredetermined by the time to maturity and two factors, the long--term interestrate and the spread (difference between the long--term rate and theshort--term (instantaneous) riskless rate). Assuming that both factorsfollow a joint Ornstein--Uhlenbeck process, a general bond pricing equationis derived. We obtain a closed--form expression for bond prices andexamine its implications for the term structure of interest rates. We alsoderive a closed--form solution for interest rate derivatives prices. Thisexpression is applied to price European options on discount bonds andmore complex types of options. Finally, empirical evidence of the model'sperformance is presented.

Dynamic structure function in 3-4He mixtures

Relevant features of the dynamic structure function S(q,¿) in 3-4He mixtures at zero temperature are investigated starting from known properties of the ground state. Sum rules are used to fix rigorous constraints to the different contributions to S(q,¿), coming from 3He and 4He elementary excitations, as well as to explore the role of the cross term S(3,4)(q,¿). Both the low-q (phonon-roton 4He excitations and 1p-1h 3He excitations) and high-q (deep-inelastic-scattering) ranges are discussed.

Quantum wire with periodic serial structure

Electron wave motion in a quantum wire with periodic structure is treated by direct solution of the Schrödinger equation as a mode-matching problem. Our method is particularly useful for a wire consisting of several distinct units, where the total transfer matrix for wave propagation is just the product of those for its basic units. It is generally applicable to any linearly connected serial device, and it can be implemented on a small computer. The one-dimensional mesoscopic crystal recently considered by Ulloa, Castaño, and Kirczenow [Phys. Rev. B 41, 12 350 (1990)] is discussed with our method, and is shown to be a strictly one-dimensional problem. Electron motion in the multiple-stub T-shaped potential well considered by Sols et al. [J. Appl. Phys. 66, 3892 (1989)] is also treated. A structure combining features of both of these is investigated

Quantum wire with periodic serial structure

Electron wave motion in a quantum wire with periodic structure is treated by direct solution of the Schrödinger equation as a mode-matching problem. Our method is particularly useful for a wire consisting of several distinct units, where the total transfer matrix for wave propagation is just the product of those for its basic units. It is generally applicable to any linearly connected serial device, and it can be implemented on a small computer. The one-dimensional mesoscopic crystal recently considered by Ulloa, Castaño, and Kirczenow [Phys. Rev. B 41, 12 350 (1990)] is discussed with our method, and is shown to be a strictly one-dimensional problem. Electron motion in the multiple-stub T-shaped potential well considered by Sols et al. [J. Appl. Phys. 66, 3892 (1989)] is also treated. A structure combining features of both of these is investigated.

Structure and magnetic properties of Sm/Fe multilayers versus substrate temperature

Three Sm(2 Å)/Fe(3 Å) multilayers have been made using two electron beams in a high vacuum chamber onto very thin Kapton foils at different substrate temperatures, (Ts=40°C, 150°C and 230°C), with the same total thickness of 3000 Å. We have found that the substrate temperature strongly affects structure and magnetic properties of the samples. For a substrate temperature of 150°C the sample behaves as a three dimensional random magnet.

Effects of Pig Slurry Application and Crops on Phosphorus Content in Soil and the Chemical Species in Solution

The application of pig slurry rates and plant cultivation can modify the soil phosphorus (P) content and distribution of chemical species in solution. The purpose of this study was to evaluate the total P, available P and P in solution, and the distribution of chemical P species in solution, in a soil under longstanding pig slurry applications and crop cultivation. The study was carried out in soil columns with undisturbed structure, collected in an experiment conducted for eight years in the experimental unit of the Universidade Federal de Santa Maria (UFSM), Santa Maria (RS). The soil was an Argissolo Vermelho distrófico arênico (Typic Hapludalf), subjected to applications of 0, 20, 40, and 80 m3 ha-1 pig slurry. Soil samples were collected from the layers 0-5, 5-10, 10-20, 20-30, 30-40, and 40-60 cm, before and after black oat and maize grown in a greenhouse, for the determination of available P, total P and P in the soil solution. In the solution, the concentration of the major cations, anions, dissolved organic carbon (DOC), and pH were determined. The distribution of chemical P species was determined by software Visual Minteq. The 21 pig slurry applications increased the total P content in the soil to a depth of 40 cm, and the P extracted by Mehlich-1 and from the solution to a depth of 30 cm. Successive applications of pig slurry changed the balance between the solid and liquid phases in the surface soil layers, increasing the proportion of the total amount of P present in the soil solution, aside from changing the chemical species in the solution, reducing the percentage complexed with Al and increasing the one complexed with Ca and Mg in the layers 0-5 and 5-10 cm. Black oat and maize cultivation increased pH in the solution, thereby increasing the proportion of HPO42- and reducing H2PO4- species.

Neutron structure of type-III antifreeze protein allows the reconstruction of AFP-ice interface.

Antifreeze proteins (AFPs) inhibit ice growth at sub-zero temperatures. The prototypical type-III AFPs have been extensively studied, notably by X-ray crystallography, solid-state and solution NMR, and mutagenesis, leading to the identification of a compound ice-binding surface (IBS) composed of two adjacent ice-binding sections, each which binds to particular lattice planes of ice crystals, poisoning their growth. This surface, including many hydrophobic and some hydrophilic residues, has been extensively used to model the interaction of AFP with ice. Experimentally observed water molecules facing the IBS have been used in an attempt to validate these models. However, these trials have been hindered by the limited capability of X-ray crystallography to reliably identify all water molecules of the hydration layer. Due to the strong diffraction signal from both the oxygen and deuterium atoms, neutron diffraction provides a more effective way to determine the water molecule positions (as D(2) O). Here we report the successful structure determination at 293 K of fully perdeuterated type-III AFP by joint X-ray and neutron diffraction providing a very detailed description of the protein and its solvent structure. X-ray data were collected to a resolution of 1.05 Å, and neutron Laue data to a resolution of 1.85 Å with a "radically small" crystal volume of 0.13 mm(3). The identification of a tetrahedral water cluster in nuclear scattering density maps has allowed the reconstruction of the IBS-bound ice crystal primary prismatic face. Analysis of the interactions between the IBS and the bound ice crystal primary prismatic face indicates the role of the hydrophobic residues, which are found to bind inside the holes of the ice surface, thus explaining the specificity of AFPs for ice versus water.

Cardiac structure and function in the obese: a cardiovascular magnetic resonance imaging study.

BACKGROUND: Obesity is a major health problem in the Western world. Among obese subjects cardiac pathology is common, but conventional noninvasive imaging modalities are often suboptimal for detailed evaluation of cardiac structure and function. We investigated whether cardiovascular magnetic resonance imaging (CMR) can better characterize possible cardiac abnormalities associated with obesity, in the absence of other confounding comorbidities. METHODS: In this prospective cross-sectional study, CMR was used to quantify left and right ventricular volumes, ejection fraction, mass, cardiac output, and apical left ventricular rotation in 25 clinically healthy obese men and 25 age-matched lean controls. RESULTS: Obese subjects had higher left ventricular mass (203 +/- 38 g vs. 163 +/- 22 g, p < 0.001), end-diastolic volume (176 +/- 29 mL vs. 156 +/- 25 mL, p < 0.05), and cardiac output (8.2 +/- 1.2 L/min vs. 6.4 +/- 1.3 L/min, p < 0.001). The obese also had increased right ventricular mass (105 +/- 25 g vs. 87 +/- 18 g, p < 0.005) and end-diastolic volume (179 +/- 36 mL vs. 155 +/- 28 mL, p < 0.05). When indexed for height, differences in left and right ventricular mass, and left ventricular end-diastolic volume remained significant. Apical left ventricular rotation and rotational velocity patterns were also different between obese and lean subjects. CONCLUSIONS: Obesity is independently associated with remodeling of the heart. Cardiovascular magnetic resonance imaging identifies subtle cardiac abnormalities and may be the preferred imaging technique to evaluate cardiac structure and function in the obese.

The Brief Psychiatric Rating Scale (version 4.0) factorial structure and its sensitivity in the treatment of outpatients with unipolar depression.

The 24-item Brief Psychiatric Rating Scale (BPRS, version 4.0) enables the rater to measure psychopathology severity. Still, little is known about the BPRS's reliability and validity outside of the psychosis spectrum. The aim of this study was to examine the factorial structure and sensitivity to change of the BPRS in patients with unipolar depression. Two hundred and forty outpatients with unipolar depression were administered the 24-item BPRS. Assessments were conducted at intake and at post-treatment in a Crisis Intervention Centre. An exploratory factor analysis of the 24-item BPRS produced a six-factor solution labelled "Mood disturbance", "Reality distortion", "Activation", "Apathy", "Disorganization", and "Somatization". The reduction of the total BPRS score and dimensional scores, except for "Activation", indicates that the 24-item BPRS is sensitive to change as shown in patients that appeared to have benefited from crisis treatment. The findings suggest that the 24-item BPRS could be a useful instrument to measure symptom severity and change in symptom status in outpatients presenting with unipolar depression.

Percolation and three-dimensional structure of supercritical water

It is well established that at ambient and supercooled conditions water can be described as a percolating network of H bonds. This work is aimed at identifying, by neutron diffraction experiments combined with computer simulations, a percolation line in supercritical water, where the extension of the H-bond network is in question. It is found that in real supercritical water liquidlike states are observed at or above the percolation threshold, while below this threshold gaslike water forms small, sheetlike configurations. Inspection of the three-dimensional arrangement of water molecules suggests that crossing of this percolation line is accompa- nied by a change of symmetry in the first neighboring shell of molecules from trigonal below the line to tetrahedral above.

The organizational structure of online academic advising

Academic advising is a key element for learning success in virtual environments that has received little attention from researchers. This paper focuses on the organizational arrangements needed for the delivery of academic advising in online higher education. We present the general dimensions of organizational structures (division of labor, hierarchy of authority and formalization) and their possible forms when applied to academic advising. The specific solution adopted at the Open University of Catalonia is described and assessed in order to draw general conclusions of interest for other institutions.

Structure, bioactivity and synthesis of natural products with hexahydropyrrolo[2,3-b]indole

Research on natural products containing hexahydropyrrolo[2,3-b]indole (HPI) has dramatically increased during the past few years. Newly discovered natural products with complex structures and important biological activities have recently been isolated and synthesized. This review summarizes the structures, biological activities, and synthetic routes for natural compounds containing HPI, emphasizing the different strategies for assembling this motif. It covers a broad gamut of molecules, from small alkaloids to complex peptides.

Value added logistical support service: logistics cost structure and performance in the new concept. Part 3

The aim of this study is to present an Activity-Based Costing spreadsheet tool for analyzing the logistics costs. The tool can be used both by customer-companies and logistics service providers. The study discusses the influence of different activity models on costs. Additionally this paper discusses about the logistical performance across the total supply chain This study is carried out using ananalytical research approach and literature material has been used for supplementing the concerned research approach. Cost structure analysis was based on the theory of activity-based management. This study was outlined to spare part logistics in machine-shop industry. The outlines of logistics services and logisticalperformance discussed in this report are based on the new logistics business concept (LMS-concept), which has been presented earlier in the Valssi-project. Oneof the aims of this study is to increase awareness of different activity modelson logistics costs. The report paints an overall picture about the business environment and requirements for the new logistics concept.

Cryo-negative staining: advantages and applications for three-dimensional electron microscopy of biological macromolecules

Les échantillons biologiques ne s?arrangent pas toujours en objets ordonnés (cristaux 2D ou hélices) nécessaires pour la microscopie électronique ni en cristaux 3D parfaitement ordonnés pour la cristallographie rayons X alors que de nombreux spécimens sont tout simplement trop << gros D pour la spectroscopie NMR. C?est pour ces raisons que l?analyse de particules isolées par la cryo-microscopie électronique est devenue une technique de plus en plus importante pour déterminer la structure de macromolécules. Néanmoins, le faible rapport signal-sur-bruit ainsi que la forte sensibilité des échantillons biologiques natifs face au faisceau électronique restent deux parmi les facteurs limitant la résolution. La cryo-coloration négative est une technique récemment développée permettant l?observation des échantillons biologiques avec le microscope électronique. Ils sont observés à l?état vitrifié et à basse température, en présence d?un colorant (molybdate d?ammonium). Les avantages de la cryo-coloration négative sont étudiés dans ce travail. Les résultats obtenus révèlent que les problèmes majeurs peuvent êtres évités par l?utilisation de cette nouvelle technique. Les échantillons sont représentés fidèlement avec un SNR 10 fois plus important que dans le cas des échantillons dans l?eau. De plus, la comparaison de données obtenues après de multiples expositions montre que les dégâts liés au faisceau électronique sont réduits considérablement. D?autre part, les résultats exposés mettent en évidence que la technique est idéale pour l?analyse à haute résolution de macromolécules biologiques. La solution vitrifiée de molybdate d?ammonium entourant l?échantillon n?empêche pas l?accès à la structure interne de la protéine. Finalement, plusieurs exemples d?application démontrent les avantages de cette technique nouvellement développée.<br/><br/>Many biological specimens do not arrange themselves in ordered assemblies (tubular or flat 2D crystals) suitable for electron crystallography, nor in perfectly ordered 3D crystals for X-ray diffraction; many other are simply too large to be approached by NMR spectroscopy. Therefore, single-particles analysis has become a progressively more important technique for structural determination of large isolated macromolecules by cryo-electron microscopy. Nevertheless, the low signal-to-noise ratio and the high electron-beam sensitivity of biological samples remain two main resolution-limiting factors, when the specimens are observed in their native state. Cryo-negative staining is a recently developed technique that allows the study of biological samples with the electron microscope. The samples are observed at low temperature, in the vitrified state, but in presence of a stain (ammonium molybdate). In the present work, the advantages of this novel technique are investigated: it is shown that cryo-negative staining can generally overcome most of the problems encountered with cryo-electron microscopy of vitrified native suspension of biological particles. The specimens are faithfully represented with a 10-times higher SNR than in the case of unstained samples. Beam-damage is found to be considerably reduced by comparison of multiple-exposure series of both stained and unstained samples. The present report also demonstrates that cryo-negative staining is capable of high- resolution analysis of biological macromolecules. The vitrified stain solution surrounding the sample does not forbid the access to the interna1 features (ie. the secondary structure) of a protein. This finding is of direct interest for the structural biologist trying to combine electron microscopy and X-ray data. developed electron microscopy technique. Finally, several application examples demonstrate the advantages of this newly