Underpricing of venture backed IPOs: a meta-analysis approach

Listing firms are subject to underpricing mainly because of asymmetries of information, but IPOs backed by a venture capitalist are generally found to be subject to less underpricing. Although this condition is commonly verified by the empirical evidence, a consistent number of studies finds contrasting results. This paper aims to answer to the question: do venture capitalists effectively reduce underpricing at IPO? Evidence provides a negative answer, with venture-backed IPOs having higher underpricing especially in US markets. Meta-regression results confirm the different effect of VC between US and European IPOs. Results overall suggest that other explanations on underpricing might hold in US markets

Discovery of parity-violating Majorana fermions in a chiral superconductor Sr2RuO4

We found parity-violating Majorana fermions in a chiral superconductor Sr2RuO4. The current-voltage curves show an anomalous behavior: The induced voltage is an even function of the bias current. The magnetic field dependent results suggest the excitation of the Majorana fermions along the closed chiral edge current of the single domain under bias current. We also discuss the relationship between a change of the chirality and spontaneous magnetization of the single domain Sr2RuO4

Nonlocal transport in the charge density waves of oo-TaS3_3

We studied the nonlocal transport of a quasi-one dimensional conductor $o$-TaS$_3$. Electric transport phenomena in charge density waves include the thermally-excited quasiparticles, and collective motion of charge density waves (CDW). In spite of its long-range correlation, the collective motion of a CDW does not extend far beyond the electrodes, where phase slippage breaks the correlation. We found that nonlocal voltages appeared in the CDW of $o$-TaS$_3$, both below and above the threshold field for CDW sliding. The temperature dependence of the nonlocal voltage suggests that the observed nonlocal voltage originates from the CDW even below the threshold field. Moreover, our observation of nonlocal voltages in both the pinned and sliding states reveals the existence of a carrier with long-range correlation, in addition to sliding CDWs and thermally-excited quasiparticles.Comment: 8 pages, 4 figure

Intravenous cocaine, morphine and amphetamine preferentially increase extracellular dopamine in the 'shell' as compared to the 'core' of the rat nucleus accumbens.

The nucleus accumbens is considered a critical target of the action of drugs of abuse. In this nucleus a "shell" and a "core" have been distinguished on the basis of anatomical and histochemical criteria. The present study investigated the effect in freely moving rats of intravenous cocaine, amphetamine, and morphine on extracellular dopamine concentrations in the nucleus accumbens shell and core by means of microdialysis with vertically implanted concentric probes. Doses selected were in the range of those known to sustain drug self-administration in rats. Morphine, at 0.2 and 0.4 mg/kg, and cocaine, at 0.5 mg/kg, increased extracellular dopamine selectivity in the shell. Higher doses of cocaine (1.0 mg/kg) and the lowest dose of amphetamine tested (0.125 mg/kg) increased extracellular dopamine both in the shell and in the core, but the effect was significantly more pronounced in the shell compared with the core. Only the highest dose of amphetamine (0.250 mg/kg) increased extracellular dopamine in the shell and in the core to a similar extent. The present results provide in vivo neurochemical evidence for a functional compartmentation within the nucleus accumbens and for a preferential effect of psychostimulants and morphine in the shell of the nucleus accumbens at doses known to sustain intravenous drug self-administration

Ascertaining the Ideality of Photometric Stereo Datasets under Unknown Lighting

The standard photometric stereo model makes several assumptions that are rarely verified in experimental datasets. In particular, the observed object should behave as a Lambertian reflector, and the light sources should be positioned at an infinite distance from it, along a known direction. Even when Lambert’s law is approximately fulfilled, an accurate assessment of the relative position between the light source and the target is often unavailable in real situations. The Hayakawa procedure is a computational method for estimating such information directly from data images. It occasionally breaks down when some of the available images excessively deviate from ideality. This is generally due to observing a non-Lambertian surface, or illuminating it from a close distance, or both. Indeed, in narrow shooting scenarios, typical, e.g., of archaeological excavation sites, it is impossible to position a flashlight at a sufficient distance from the observed surface. It is then necessary to understand if a given dataset is reliable and which images should be selected to better reconstruct the target. In this paper, we propose some algorithms to perform this task and explore their effectiveness

Natural convection heat transfer from a ribbed vertical plate: Effect of rib size, pitch, and truncation

Buoyancy-induced flows over ribbed vertical surfaces involve complex thermal and dynamic interactions between the mainstream and the surface texture, yielding contrasting effects on the heat transfer performance of the heated plate; proper analysis of the overall effect on the heat transfer rate is essential for efficient operation and optimization purposes. The present work pursues an insight into the different factors controlling this problem. Natural convection heat transfer from a vertical plate of 0.5 m height, regularly roughened with wooden transverse square ribs, is experimentally investigated. The surface temperature of the baseplate is varied so that a range of the plate Rayleigh number (Ra) from 3.4 × 108 to 4.9 × 108 is covered. The density of the roughness pattern and the rib pitch-to-height ratio (P/e) are varied by changing the number of ribs attached to the surface (from 10 to 40 rib rows) and using three different square cross-sections (of side lengths 2, 3, or 5 mm). The experimental work relies on the schlieren optical technique, through which the thermal boundary layer is visualized and the Nusselt number distribution is acquired. Analysis of the results reveals that enhancement of the local Nusselt number, relative to a corresponding smooth surface, may be attained only at the central part of the inter-rib region; this occurs exclusively for relatively large values of P/e. At a later stage, the effectiveness of rib truncation in enhancing the heat transfer from the baseplate is explored. Three staggered arrangements are considered, by varying the number of rib segments per row, and heat transfer enhancement, sensitive to the number of rib segments per row, is found. This paper also provides insight into the role of thermal-field disturbances close to turbulent transition, and sheds light on the potential of truncated ribs to amplify such perturbations

The impact of City Logistics on Retailers inventory management: an exploratory analysis

City Logistics (CL) can be defined as a comprehensive solution aimed at “totally optimizing” the logistics and transport activities in urban areas, by considering the environment, the congestion and energy consumption. Many CL initiatives have been implemented to improve the efficiency and the effectiveness of the urban logistics processes. The adoption of such initiatives by logistics service providers implies a reshaping of supply chains configuration in terms of vehicles used as well as consolidation and reception of goods. Therefore, CL initiatives are likely to have an impact on the inventory policy of the retailers, in terms of order frequency, time windows for receiving the deliveries, and batching lots. In this context, there is a lack of studies investigating the influence of CL on retailers’ inventory management practices. In order to bridge this research gap, this paper proposes an exploratory analysis of the perception of the CL issues by apparel and grocery store managers and owners. To this end, a survey is submitted to retailers of different sizes and type (e.g. multi-brand vs. mono-brand) located in the limited traffic zone (LTZ) of Turin (Italy). The objective of this analysis is twofold. First, the survey aims at confirming the findings from inventory policy literature and outlining different profiles of retailers based on the factors that characterize their inventory policy. Second, the shopkeepers’ perception, both positive and negative, of three different CL innovations is explored. Results show that there is a wide variety of inventory management practices even within an enclosed environment such as the one of a city’s LTZ, and that the adoption of CL innovations by retailers might depend strongly on their inventory policy. Therefore, logistics service providers and local administrations need to take into account such diversity if they intend to scale up CL innovations

Superconducting networks with the proximity effect

We report on the first observation of a novel type of superconducting proximity network using a superconductor-normal metal bilayer. Little-Parks oscillation measurements show that the superconducting current flows through a path enclosed by the edge rather than by the center of the Pb/Au wire in the network. Furthermore, several peaks were observed in a power spectrum analysis. We observed that the sequence of these peaks and that of the monolayer network were connected by the power function, which is a factor of the line width, S_{B_n} = \alpha^{n-2}S_{A_n}. This suggests that even in a proximity network vortices are arranged in a way identical to a monolayer network.Comment: 13 pages, 5 figure

Application of optical methods to the study of convective heat transfer in rib-roughened channels

The non-invasive liquid-crystal and schlieren methods have been applied to the study of convective heat transfer in rib-roughened channels. The importance of investigating heat transfer from rib-roughened surfaces and of using non-invasive tools to gain information on thermal fields for similar complex geometries is stressed in Chapter 1. Chapter 2 is devoted to a description of main important published papers related to this project. Firstly, studies concerning heat transfer from rib-roughened surfaces in forced and free convection are listed and discussed in detail. Moreover, a literature survey on optical methods in heat transfer is presented, with special attention to the methods (liquid-crystal thermography and schlieren) applied in this study. Experiments performed by using liquid-crystal thermography are presented and discussed in Chapter 3. Three configuration geometries have been investigated: a smooth channel (having flat plates) and two different ribbed channels. The investigated heat transfer mechanism was forced convection. These experiments were performed at City University, London. Chapter 4 is devoted to experiments performed by using the schlieren optical technique. Again, the experimental study included a preliminary activity on smooth channels, followed by tests performed for rib-roughened channels. The heat transfer mechanism was natural convection. These experiments, which constitute the main body of the project, were conducted at the Dipartimento di Termoenergetica e Condizionamento Ambientale, Universita di Genova, Italy. Finally, most important conclusions are drawn in Chapter 5. Details of relationships between the recorded optical data and the thermal field (or heat transfer coefficients) are reported in Appendix Al and A2 for the liquid-crystal thermography and the schlieren method, respectively