10,974 research outputs found
Sound
Sound, basically characterized as air in motion
since ancient Greece, has been at the core of the
theories of many philosophers, as well as musicians,
poets, scientists, and theologians. Under
the auspices of Hellenic thought, Renaissance
scholars tried to define what sound is,
unveiling its vibrating forces to understand its
ability to shake the human body and soul. In
such a way, the ever-present metaphors of harmony
were much more than mere imagined,
unreal thoughts: through them, Renaissance
humanists shaped, organized, and understood
the structure and passions of the world itself.Este trabajo forma parte del proyecto de investigación “La obra musical renacentista: fundamentos, repertorios y prácticas” HAR 2015-70181-P (MINECO/FEDER, UE
RETAILER LOCATIONS, LOCAL SUPPLY AND PRICE POLICIES
Two retailers operate in a monopsonistic, oligopolistic environment. They have to buy from spatially dispersed suppliers and use uniform pricing downstream. We characterize prices and location in the two-stage location-then-price game under two different pricing policies in the upstream market: uniform pricing and spatial price discrimination. We analyze how local supply conditions affect equilibrium locations and profits. We show that if retailers can choose a price policy initially they commit to uniform pricing in the upstream market.Spatial Competition; Intermediation; Uniform Pricing
Corporate Valuation and Governance: Evidence from Colombia
We examine for the first time the association of different measures of ownership and control, and separation ratios with firm’s value and performance for 108 non-financial firms that traded their stock during the period 1998 to 2002. We found that large blockholders exert a positive influence upon firm’s valuation and performance, which validates the positive monitoring approach of large shareholders, but also found that this relation is not monotone implying that when separation of control and ownership tends to increase, a negative effect is exerted on firm’s valuation. Furthermore, we report first estimates of a survey of corporate governance practices conducted in 2004 for 43 Colombian non-financial companies. The index’s scores suggest that implementation of good governance in Colombian firms has been slow and poor as measured by the average of the Index that is below half the maximum attainable value. Regrettably, we did not find any support to recent theories that predict a positive association between good governance practices, measured by the CGI, and performance. At most there exists a positive relationship for sub-index but the results were not statistically significant in general.Ownership, Control, Corporate Governance, Colombia
Corporate Valuation and Governance: Evidence from Colombia
This paper examines for the first time the association of different ownership and control measures and separation ratios with a firm`s value and performance for 108 non-financial firms that traded their stock during the period 1998 to 2002. Large blockholders were found to exert a positive influence upon a firm`s valuation and performance, which validates the positive monitoring approach of large shareholders, but it was also found that this relationship is not monotonic, implying that when separation of control and ownership tends to increase, a negative effect is exerted on firm`s valuation. This paper also reports the first estimates of a survey of corporate governance practices conducted in 2004 for 43 Colombian non-financial companies. The corporate governance index`s (CGI) scores suggest that implementation of good governance in Colombian firms has been slow and poor, as measured by an index average that is below half the maximum attainable value. Regrettably, it was not possible to find any support to recent theories that predict a positive association between good governance practices -as measured by the CGI - and performance. At most, there exists a positive relationship for the sub-index, but the results were not statistically significant in general.
Corporate Governance and Firm Valuation in Colombia
This paper studies the separation of ownership and control of 108 listed companies in Colombia from 1996 to 2002, finding that voting rights are greater than cash flow rights because of indirect ownership across firms. The paper also examines the association of various ownership and control measures and separation ratios with a firm’s value and performance for the same sample of companies that traded their stock from 1998 to 2002. Large blockholders were found to exert a positive influence upon a firm’s valuation and performance, which validates the positive monitoring approach of large shareholders, but this relationship is not monotonic. The paper further reports results from a 2004 survey which suggests that Colombian firms have been slow to improve their corporate governance practices.
Service provision on a network with endogenous consumption capacity
We present a model in which the consumers' capacity to access a service provided on a network depends negatively on the price charged by the network owner per capacity unit. Several scenarios concerning the structure of the downstream service provision market are studied. First, a monopolist operates in both the network and the service provision stage. Second, we assume duopolistic competition between the network owner and the entrant. Third, we allow for endogenous differentiation of the services provided by the two competitors. Generally speaking, the duopolistic structure does not necessarily enhance consumer surplus. Furthermore, competition in the service provision market may reduce social welfare, either due to excessive differentiation or due to a low network density.telecommunications markets, regulation, endogenous consumption.
The convex hull of a finite set
We study -separately convex hulls of finite
sets of points in , as introduced in
\cite{KirchheimMullerSverak2003}. When is considered as a
certain subset of matrices, this notion of convexity corresponds
to rank-one convex convexity . If is identified instead
with a subset of matrices, it actually agrees with the quasiconvex
hull, due to a recent result \cite{HarrisKirchheimLin18}.
We introduce " complexes", which generalize constructions. For a
finite set , a " -complex" is a complex whose extremal points
belong to . The "-complex convex hull of ", , is the union
of all -complexes. We prove that is contained in the
convex hull .
We also consider outer approximations to convexity based in the
locality theorem \cite[4.7]{Kirchheim2003}. Starting with a crude outer
approximation we iteratively chop off "-prisms". For the examples in
\cite{KirchheimMullerSverak2003}, and many others, this procedure reaches a
" -complex" in a finite number of steps, and thus computes the
convex hull.
We show examples of finite sets for which this procedure does not reach the
convex hull in finite time, but we show that a sequence of outer
approximations built with -prisms converges to a -complex. We
conclude that is always a " -complex", which has interesting
consequences
Description and molecular phylogeny of a new and one known needle nematode of the genus Paralongidorus (Nematoda: Longidoridae) from grapevine in Portugal
A new and a known longidorid nematode, Paralongidorus lusitanicus n. sp. and Paralongidorus plesioepimikis, are described and illustrated from populations extracted from soil associated with grapevine (Vitis vinifera L.) from Escaroupim and Pó (central-Western Portugal), respectively. The new needle nematode P. lusitanicus n. sp. is characterised by a very large body size (8072–12,022 μm), an expanded and rounded lip region, ca 30 μm wide, with a clear constriction followed by a depression posterior to the amphidial aperture, amphidial fovea very large (11.0–19.0 μm), stirrup-shaped, with conspicuous slit-like aperture as shown in scanning electron microscopy studies, a very long and flexible odontostyle (180.0–223.0 μm), guiding ring located at 28.0–41.5 μm from anterior end, vulva anterior to the mid-body (34–41%), a dorsally convex-conoid tail with rounded terminus (29–42 μm long), bearing two or three pairs of caudal pores and males common (ratio 1:1.6 females) with spicules ca 80 μm long. Morphological and morphometric traits for P. plesioepimikis fit well with the original description, and is reported for the first time in Portugal. Integrative diagnosis of both species was completed with molecular data obtained using D2-D3 expansion segments of 28S rDNA, ITS1-rDNA and partial 18S–rDNA. The phylogenetic relationships of these species with other Paralongidorus spp. using these three molecular markers indicated that P. lusitanicus n. sp. clustered together with other Paralongidorus spp. forming a sister clade with P. plesioepimikis, both of them sharing a large body, long odontostyle, an anteriorly located vulva and an expanded and rounded lip region with a clear constriction followed by a depression posterior to the amphidial aperture
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