Optimal capital structure: a trade-off model and its empirical testing

In the present research we have set forth a new, simple, Trade-Off model that would allow us to calculate how much debt and, by default, how much equity a company should have, using easily available information and calculating the cost of debt dynamically on the basis of the effect that the capital structure of the company has on the risk of bankruptcy; in an attempt to answer this question. The proposed model has been applied to the companies that make up the Dow Jones Industrial Average (DJIA) in 2007. We have used consolidated financial data from 1996 to 2006, published by Bloomberg. We have used simplex optimization method to find the debt level that maximizes firm value. Then, we compare the estimated debt with real debt of companies using statistical nonparametric Mann-Whitney. The results indicate that 63% of companies do not show a statistically significant difference between the real and the estimated debt.

L'aprofitament ramader a la vall del Madriu-Perafita-Claror (Principat d'Andorra)

The farming exploitation in the Madriu-Perafita-Claror Valley (Principality of Andorra). The Madriu-Perafita-Claror Valley, a natural space located in the Principality of Andorra, has kept a high ecological and landscape value through time. At present, the Valley is considered in the cultural landscape category of the UNESCO World-wide Heritage. A study of the spatial variability of pastures in the Valley conducted from 1994 to 2003 concluded that there was an optimistic future for livestock. This future was mainly explained by new policies in the country, as well as by the new hopes of the tockbreeders. The study also stated that cattle and horse movements within the Valley did not varied over the study period, although entrance and exit points changed. Sheep only fed in the Madriu-Perafita-Claror Valley, but it wouldbe convenient its introduction in other areas where horses and cattle did not pasture. The study concluded that the use of the Valley by the stockbreeders contributed to the development of the vegetation and the landscape, and that the livestock is very important to keep natural and landscape values of the Valley.

Re-writing and Its Pedagogical Value: A Case Study

Tenint en compte el temps i la energia que els mestres i professors dediquen a la correcció de redaccions i produccions escrites i el poc efecte que aquestes semblen tenir en altres produccions dels aprenents, es va dissenyar la recerca que es presenta en aquest article. Els resultats de l'estudi semblen suggerir que les correccions no faciliten l'aprenentatge. Com presentem aquesta activitat de retroalimentació a l'alumnat i la posició que li donem dins d'un enfocament basat en el procés de l'escriptura seran clau per fer que les correccions siguin facilitadores de l'aprenentatge de la producció escrita.

La planificació estratègica i la gestió de projectes. Una línia de canvi de present i de futur a la Secretaria de Política Lingüística

L’article situa el procés de planificació estratègica que ha iniciat la Secretaria de Política Lingüística en el context dels reptes que afronta la gestió pública en un moment de transformació social i tecnològica. En aquest àmbit destaca la importància del treball planificat, desgrana el mètode que guiarà el procés i exposa la importància de la formació. Unes conclusions orientatives tanquen la reflexió.

Responsabilitat social de l’empresa i política lingüística. Una interessant eina de sensibilització de present i de futur

L'article explora les connexions entre la responsabilitat social corporativa (RSE) i la política lingüística. S'obre amb una introducció a la responsabililtat social corporativa; a continuació, s'aborda la compatibilitat entre aquest concepte i el de política lingüística de manera genèrica i en l'àmbit específic d'una empresa. Finalment es tracta la tasca en matèria de RSE impulsada per la Secretaria de Política Lingüística. L'article es tanca amb unes reflexions finals.

Conservation and management of the Common Quail (Coturnix coturnix) in Europe: past, present and future.

En el presente estudio hacemos una revisión del estado de conservación y las tendencias poblacionales de la codorniz común (Coturnix coturnix) desde 1900 hasta nuestros días. Algunos de los datos de los que disponemos son contradictorios con respecto al estado de la especie, que presenta ciertas características que dificultan el poder proporcionar estimas poblacionales fiables. Datos recientes sugieren claramente, tanto a escala local como a escala transnacional, que las poblaciones atlánticas de codorniz común han permanecido estables en las dos últimas décadas y que la práctica de liberar codornices criadas en granjas (híbridas con la codorniz japonesa, Coturnix japonica) con finalidades cinegéticas, no afectan significativamente a nuestras estimas. Por otra parte, los complejos patrones de desplazamiento de esta especie requieren especial atención. En este sentido, el análisis de recuperaciones de anillas puede aportar información relevante, especialmente de los movimientos nomádicos de codornices a la búsqueda de hábitats adecuados, tras la destrucción de los cultivos invernales de cereales debido a la siega. Así, al desarrollar un modelo de distribución de cría para esta especie, se debe incorporar continuamente información actualizada de los cambios estacionales de hábitat y clima, con el fin de obtener unas predicciones óptimas. En este sentido, por ejemplo, la inclusión de datos quincenales de índices de vegetación en los modelos de distribución ha dado muy buenos resultados. La obtención de predicciones fiables de los cambios de la distribución de la especie y de sus desplazamientos durante la estación de cría puede ser muy útil para un mejor conocimiento del estado de conservación y las tendencias poblacionales de la especie, así como para el diseño de futuras medidas de gestión.

BUSINESS CONCEPTS OF MOBILE VALUE-ADDED SERVICES FROM OPERATOR’S POINT OF VIEW

Tämä diplomityö on tehty Lappeenrannassa Telecom Business Research Centerin 5T-projektiin liittyen. Työssä tutkitaan matkaviestinnän lisäarvopalveluiden liiketoimintakonsepteja operaattoreiden näkökulmasta. Lisäarvopalvelut laajentavat operaattoreiden palveluvalikoimaa. Niiden osuuden telekommunikaatioalan yritysten ja erityisesti operaattoreiden tuotoista on ennustettu kasvavan huomattavasti. Työn tärkeimpänä tavoitteena on tuoda uusia näkökulmia ja lisätä ymmärrystä lisäarvopalveluiden liiketoimintakonseptin rakentamisprosessista. Tätä tietämystä käytetään edesauttamaan työn empiirisessä osuudessa tutkitun Content Gateway -tuotteen liiketoimintaa. Tarjoamalla nopean liitynnän ja laskutuskanavan ulkopuolisten palveluntarjoajien ja operaattorin välille tämä tuote mahdollistaa operaattorille ja palveluntarjoajille lisäarvopalveluiden liiketoiminnan käynnistämisen. Lisäarvopalveluiden arvonluontiprosessi vaatii lukuisia yhteistyötä tekeviä osapuolia, joiden yhteistoiminta on dynaamista ja tiedonvälitys avointa, interaktiivista ja nopeaa. Arvonluontiin liittyy myös monia konvergoituvia kehityssuuntia. Perinteinen arvoketjuajattelu on riittämätön uuteen, verkottuneeseen toimintaympäristöön ja sen tilalle on tullut modernimpi arvoverkostomalli. Arvoverkosto luo kilpailuetunsa muita verkostoja vastaan jakamalla resurssit ja kompetenssit optimaalisesti ja liittämällä strategisen ja operationaalisen johtamisen kulttuurit toisiinsa. Tässä työssä verrataan arvoverkoston teoreettisia tavoitteita kahteen lisäarvopalveluiden liiketoimintakonseptiin. Näistä ensimmäinen, i-mode –niminen konsepti on valittu vertailuun edistyksellisyytensä ja tulevaa kehitystä ennakoivien ominaispiirteidensä vuoksi. Toinen esimerkkikonsepti on rakennettu edellä mainitun Content Gateway -tuotteen ympärille. Tutkimus sisältää mm. liikekumppaneiden hankinnan, ansaintalogiikoiden ja verkostojen johtamisen analysoinnin. Työn tuloksena on saatu ohjeita siihen, miten operaattori voi rakentaa tällaista konseptia ja mitä seikkoja tulee ottaa huomioon erityisesti sanomapalveluihin liittyvässä liiketoiminnassa.

The reproductive cycle of the sea urchin Arbacia lixula in northwest mediterranean: potential influence of temperature and photoperiod

We studied the reproductive cycle of the sea urchin Arbacia lixula in a subtidal population from northeast Spain over four years using a gonadosomatic index (GSI) and gonad histology. Our results show that the GSI of A. lixula follows a seasonal cycle which peaks in May-July and attains its lowest values in October-November every year. The time course of the GSI matched closely the photoperiod cycle. We also found a remarkable inter-annual variability in the maximum value of GSI, which correlated with mean water temperature during the gonad growth period (winter and spring). Gonad histology was also in agreement with a single gametogenic cycle per year in this species. We explored the application of circular statistics to present and analyse gonadal development data, which allowed us to adequately handle the high intra-individual variability detected, with several developmental stages commonly found within the same gonad. The picture that emerged is one of a gametogenic timing driven by photoperiod, while the amount of reproductive output is determined by temperature. This is coherent with the tropical origin of the species and lends support to recent warnings about an increase in the abundance of this species in the Mediterranean as a result of global warming, with associated increased impact potential in sublittoral communities.

Comparison of quality of life after stereotactic body radiotherapy and surgery for early-stage prostate cancer

Background: As the long-term efficacy of stereotactic body radiation therapy (SBRT) becomes established and other prostate cancer treatment approaches are refined and improved, examination of quality of life (QOL) following prostate cancer treatment is critical in driving both patient and clinical treatment decisions. We present the first study to compare QOL after SBRT and radical prostatectomy, with QOL assessed at approximately the same times pre- and post-treatment and using the same validated QOL instrument. Methods: Patients with clinically localized prostate cancer were treated with either radical prostatectomy (n = 123 Spanish patients) or SBRT (n = 216 American patients). QOL was assessed using the Expanded Prostate Cancer Index Composite (EPIC) grouped into urinary, sexual, and bowel domains. For comparison purposes, SBRT EPIC data at baseline, 3 weeks, 5, 11, 24, and 36 months were compared to surgery data at baseline, 1, 6, 12, 24,and 36 months. Differences in patient characteristics between the two groups were assessed using Chi-squared tests for categorical variables and t-tests for continuous variables. Generalized estimating equation (GEE) models were constructed for each EPIC scale to account for correlation among repeated measures and used to assess the effect of treatment on QOL. Results: The largest differences in QOL occurred in the first 1-6 months after treatment, with larger declines following surgery in urinary and sexual QOL as compared to SBRT, and a larger decline in bowel QOL following SBRT as compared to surgery. Long-term urinary and sexual QOL declines remained clinically significantly lower for surgery patients but not for SBRT patients. Conclusions: Overall, these results may have implications for patient and physician clinical decision making which are often influenced by QOL. These differences in sexual, urinary and bowel QOL should be closely considered in selecting the right treatment, especially in evaluating the value of non-invasive treatments, such as SBRT.

Neutron skin thickness in the droplet model with surface width dependence: Indications of softness of the nuclear symmetry energy

We analyze the neutron skin thickness in finite nuclei with the droplet model and effective nuclear interactions. The ratio of the bulk symmetry energy J to the so-called surface stiffness coefficient Q has in the droplet model a prominent role in driving the size of neutron skins. We present a correlation between the density derivative of the nuclear symmetry energy at saturation and the J/Q ratio. We emphasize the role of the surface widths of the neutron and proton density profiles in the calculation of the neutron skin thickness when one uses realistic mean-field effective interactions. Next, taking as experimental baseline the neutron skin sizes measured in 26 antiprotonic atoms along the mass table, we explore constraints arising from neutron skins on the value of the J/Q ratio. The results favor a relatively soft symmetry energy at subsaturation densities. Our predictions are compared with the recent constraints derived from other experimental observables. Though the various extractions predict different ranges of values, one finds a narrow window L∼45-75 MeV for the coefficient L that characterizes the density derivative of the symmetry energy that is compatible with all the different empirical indications.

The Banzhaf Value in the Presence of Externalities

[eng] We propose two generalizations of the Banzhaf value for partition function form games. In both cases, our approach is based on probability distributions over the set of possible coalition structures that may arise for any given set of agents. First, we introduce a family of values, one for each collection of the latter probability distributions, defined as the Banzhaf value of an expected coalitional game. Then, we provide two characterization results for this new family of values within the framework of all partition function games. Both results rely on a property of neutrality with respect to amalgamation of players. Second, as this collusion transformation fails to be meaningful for simple games in partition function form, we propose another generalization of the Banzhaf value which also builds on probability distributions of the above type. This latter family is characterized by means of a neutrality property which uses an amalgamation transformation of players for which simple games are closed.

Thomas-Fermi theory for atomic nuclei revisited

The recently developed semiclassical variational Wigner-Kirkwood (VWK) approach is applied to finite nuclei using external potentials and self-consistent mean fields derived from Skyrme inter-actions and from relativistic mean field theory. VWK consist s of the Thomas-Fermi part plus a pure, perturbative h 2 correction. In external potentials, VWK passes through the average of the quantal values of the accumulated level density and total en energy as a function of the Fermi energy. However, there is a problem of overbinding when the energy per particle is displayed as a function of the particle number. The situation is analyzed comparing spherical and deformed harmonic oscillator potentials. In the self-consistent case, we show for Skyrme forces that VWK binding energies are very close to those obtained from extended Thomas-Fermi functionals of h 4 order, pointing to the rapid convergence of the VWK theory. This satisfying result, however, does not cure the overbinding problem, i.e., the semiclassical energies show more binding than they should. This feature is more pronounced in the case of Skyrme forces than with the relativistic mean field approach. However, even in the latter case the shell correction energy for e.g.208 Pb turns out to be only ∼ −6 MeV what is about a factor two or three off the generally accepted value. As an adhoc remedy, increasing the kinetic energy by 2.5%, leads to shell correction energies well acceptable throughout the periodic table. The general importance of the present studies for other finite Fermi systems, self-bound or in external potentials, is pointed out.

Quantifying the time for accurate EEG decoding of single value-based decisions.

BACKGROUND: Recent neuroimaging studies suggest that value-based decision-making may rely on mechanisms of evidence accumulation. However no studies have explicitly investigated the time when single decisions are taken based on such an accumulation process. NEW METHOD: Here, we outline a novel electroencephalography (EEG) decoding technique which is based on accumulating the probability of appearance of prototypical voltage topographies and can be used for predicting subjects' decisions. We use this approach for studying the time-course of single decisions, during a task where subjects were asked to compare reward vs. loss points for accepting or rejecting offers. RESULTS: We show that based on this new method, we can accurately decode decisions for the majority of the subjects. The typical time-period for accurate decoding was modulated by task difficulty on a trial-by-trial basis. Typical latencies of when decisions are made were detected at ∼500ms for 'easy' vs. ∼700ms for 'hard' decisions, well before subjects' response (∼340ms). Importantly, this decision time correlated with the drift rates of a diffusion model, evaluated independently at the behavioral level. COMPARISON WITH EXISTING METHOD(S): We compare the performance of our algorithm with logistic regression and support vector machine and show that we obtain significant results for a higher number of subjects than with these two approaches. We also carry out analyses at the average event-related potential level, for comparison with previous studies on decision-making. CONCLUSIONS: We present a novel approach for studying the timing of value-based decision-making, by accumulating patterns of topographic EEG activity at single-trial level.

The Banzhaf Value in the Presence of Externalities

[eng] We propose two generalizations of the Banzhaf value for partition function form games. In both cases, our approach is based on probability distributions over the set of possible coalition structures that may arise for any given set of agents. First, we introduce a family of values, one for each collection of the latter probability distributions, defined as the Banzhaf value of an expected coalitional game. Then, we provide two characterization results for this new family of values within the framework of all partition function games. Both results rely on a property of neutrality with respect to amalgamation of players. Second, as this collusion transformation fails to be meaningful for simple games in partition function form, we propose another generalization of the Banzhaf value which also builds on probability distributions of the above type. This latter family is characterized by means of a neutrality property which uses an amalgamation transformation of players for which simple games are closed.

Newly described human polyomaviruses Merkel Cell, KI and WU are present in urban sewage and may represent potential environmental contaminants

Recently, three new polyomaviruses (KI, WU and Merkel cell polyomavirus) have been reported to infect humans. It has also been suggested that lymphotropic polyomavirus, a virus of simian origin, infects humans. KI and WU polyomaviruses have been detected mainly in specimens from the respiratory tract while Merkel cell polyomavirus has been described in a very high percentage of Merkel cell carcinomas. The distribution, excretion level and transmission routes of these viruses remain unknown. Here we analyzed the presence and characteristics of newly described human polyomaviruses in urban sewage and river water in order to assess the excretion level and the potential role of water as a route of transmission of these viruses. Nested-PCR assays were designed for the sensitive detection of the viruses studied and the amplicons obtained were confirmed by sequencing analysis. The viruses were concentrated following a methodology previously developed for the detection of JC and BK human polyomaviruses in environmental samples. JC polyomavirus and human adenoviruses were used as markers of human contamination in the samples. Merkel cell polyomavirus was detected in 7/8 urban sewage samples collected and in 2/7 river water samples. Also one urine sample from a pregnant woman, out of 4 samples analyzed, was positive for this virus. KI and WU polyomaviruses were identified in 1/8 and 2/8 sewage samples respectively. The viral strains detected were highly homologous with other strains reported from several other geographical areas. Lymphotropic polyomavirus was not detected in any of the 13 sewage neither in 9 biosolid/sludge samples analyzed. This is the first description of a virus isolated from sewage and river water with a strong association with cancer. Our data indicate that the Merkel cell polyomavirus is prevalent in the population and that it may be disseminated through the fecal/urine contamination of water. The procedure developed may constitute a useful tool for studying the excreted strains, prevalence and transmission of these recently described polyomaviruses.