3,551 research outputs found
Financial forecasts of SMEs in IPOs: fact or fiction?
Este artículo valora el proceso de previsión financiera de las pequeñas y medianas
empresas (PYME) en sus salidas a bolsa. Específicamente, se analiza la calidad de las
previsiones de beneficios realizadas y se exploran los factores que determinan la precisión
de tales previsiones. Este estudio considera todas las empresas que han salido a cotizar al
Mercado Alternativo Bursátil español (MAB). Los resultados muestran que los directivos de
las empresas del MAB han sido mayoritariamente optimistas y altamente imprecisos en la
estimación de los beneficios futuros.This article assesses the financial forecasts of small and medium-sized enterprises (SMEs)
in their process of initial public offering (IPO). In particular, the quality of earnings forecasts is
analysed and the determinants of accuracy of earning forecasts are explored. To this end, the
empirical study considers all the companies listed on the Spanish Alternative Stock Market
(MAB). The results show that managers of newly listed Spanish SMEs have mostly been
optimistic and highly inaccurate when estimating their future earnings
Hidrofugación de rocas carbonatadas porosas: Propiedades que controlan su eficacia
La finalidad del presente estudio es la de tratar de establecer
que propiedades físicas pueden ser empleadas de una forma
rutinaria para conocer el grado de eficacia de un
tratamiento aplicado sobre un determinado sustrato pétreo.
Con esta finalidad se han seleccionado dos tipos de rocas
carbonatadas, la caliza dellontoria (Burgos) y la dolomía
deLaspra (Asturias), con una configuración del sistema
poroso muy diferente. Se han empleado tres productos
protectores de naturaleza silicoorgánica, ampliamente
utilizados, dos siloxanosy un copolimero.
Las propiedades seleccionadas (ángulo de contado y
permeabilidad al vapor de agua) han resultado idóneas para
determinar el grado de eficacia de los distintos tratamientos.
Se ha comprobado que dicho grado está condicionado por
las características químicas del producto, siendo
prácticamente nula la influencia de las características de la
roca.
Se están llevando a cabo otras investigaciones con las
mismas piedras y productos de tratamiento en un intento de
establecer correlaciones entre el grado de eficacia de dichos
tratamientos y la durabilidadThe aim of this study is to establish which physical
properties may be used, in a routine way, in order to know
the efficacy rate of a treatment applied on a specific rocky
substrate.
Whit this purpose, two types of carbonated rocks, the
limestone ofHontoria (Burgos) and the dolomite ofLaspra
(Asturias) have been chosen, with a very different
configuration of their porosity systems. Three protection
products, with silico-organic nature and widely used have
been used, to wit: two siloxenes and a copolymer.
Tue properties chosen (contact angle and water vapour
permeability) have been the proper ones in order to
determine the efficacy level of the different treatments. This
level was demonstrated to be conditioned by the chemical
characteristics of this product, and characteristics is practically null.
Other investigations are being carried out with the same
rocks and treatmen products in orderPeer reviewe
Evaluating Labor Market Reforms: A General Equilibrium Approach
Job security provisions are commonly invoked to explain the high and persistent European unemployment rates. This belief has led several countries to reform their labor markets and liberalize the use of fixed-term contracts. Despite how common such contracts have become after deregulation, there is a lack of quantitative analysis of their impact on the economy. To fill this gap, we build a general equilibrium model with heterogeneous agents and firing costs in the tradition of Hopenhayn and Rogerson (1993). We calibrate our model to Spanish data, choosing in part parameters estimated with firm-level longitudinal data. Spain is particularly interesting, since its labor regulations are among the most protective in the OECD, and both its unemployment and its share of fixed-term employment are the highest. We find that fixed term contracts increase unemployment, reduce output, and raise productivity. The welfare effects are ambiguous.Fixed-term contracts, Firing costs, General equilibrium, Heterogeneous agents
EVALUATING LABOR MARKET REFORMS: A GENERAL EQUILIBRIUM APPROACH
Job security provisions are commonly invoked to explain the high and persistent European unemployment rates. This belief has led several countries to reform their labor markets and liberalize the use of fixed-term contracts. Despite how common such contracts have become after deregulation, there is a lack of quantitative analysis of their impact on the economy. To fill this gap, we build a general equilibrium model with heterogeneous agents and firing costs in the tradition of Hopenhayn and Rogerson (1983). We calibrate our model to Spanish data, choosing in part parameters estimated with firm-level longitudinal data. Spain is particularly interesting, since its labor regulations are among the most protective in the OECD, and both its unemployment and its share of fixed-term employment are the highest. We find that fixedterm contracts increase unemployment, reduce output, and raise productivity. The welfare effects are ambiguous.
La protección al empleo en España : evolución y consecuencias
Este trabajo se centra en la influencia de las regulaciones del mercado de trabajo en el
funcionamiento de éste. Para ello, describe las reformas laborales ocurridas en Europa
en las dos últimas décadas, con especial atención al mercado de trabajo español. A este
mercado, que ha registrado históricamente las mayores tasas de paro de la OCDE, su
grado de protección al empleo lo ha situado como uno de los mercados de trabajo
menos flexible del mundo. Se investigan las consecuencias de la protección al empleo en
España tanto a nivel micro como macroeconómico. Asimismo, se describen las
principales características de la economía española y los desafíos y problemas a los que
se enfrenta su mercado de trabajo en el futuro próximoLos autores agradecen la financiación del Ministerio de Educación y Ciencia a través de los proyectos SEJ2006-05710/ECON y SEJ2005-03470/ECON, respectivamentePublicad
Assessment of Postural Load during Melon Cultivation in Mediterranean Greenhouses
Health and safety at work directly influence the development of sustainable agriculture. In the agricultural sector, many farm workers suffer musculoskeletal disorders caused by forced posture. The objective of this research is to assess working postures during melon cultivation in Almería-type greenhouses. The Ovako Working Posture Assessment System (OWAS) has been used with pictures of the tasks. The variables studied by multiple correspondence analysis were as follows: Subtask, Posture code, Back, Arms, Legs, Load, Risk, and Risk combination. The OWAS analysis showed that 47.57% of the postures were assessed as risk category 2, 14.32% as risk category 3, 0.47% as risk category 4, and the rest as risk category 1. Corrective measures should be implemented immediately, as soon as possible, or in the near future, depending on the risks detected
MIRACLE’s hybrid approach to bilingual and monolingual Information Retrieval
The main goal of the bilingual and monolingual participation of the MIRACLE team at CLEF 2004 was testing the effect of combination approaches to information retrieval. The starting point is a set of basic components: stemming, transformation, filtering, generation of n-grams, weighting and relevance feedback. Some of these basic components are used in different combinations and order of application for document indexing and for query processing. Besides this, a second order combination is done, mainly by averaging or by selective combination of the documents retrieved by different approaches for a particular query
Visual and refractive outcomes of 100 small incision lenticule extractions (SMILE) in moderate and high myopia: a 24-month follow-up study
Purpose: We aimed to present the visual results obtained in 100 small incision lenticule extraction (SMILE) refractive surgeries, demonstrate whether the technique is effective in the treatment of moderate and high myopia, and observe the follow-up of these patients over 24-month period. Methods: One hundred eyes of 50 consecutive patients were treated with SMILE. The preoperative spherical equivalent refraction was − 5.64 ± 1.23 D. During the postoperative period, patients were examined at 3, 6, 12, and 24 months. We analysed the efficacy, safety, predictability, and stability of the technique. Results: The Snellen visual acuity of 99% of the patients was 20/20 or better after 24 months of follow-up. Two eyes had a loss of two lines of visual acuity; 1% of the patients had a loss of one line of visual acuity. The postoperative spherical refraction was − 0.04 ± 0.35 D (− 1.00 to 0.50 D). The postoperative spherical equivalent refraction was − 0.19 ± 0.38 D (− 1.25 to 0.50 D). Eighty-three percent of the eyes were within ± 0.50 D, and 87% obtained a residual astigmatism of 0.50 D or less. Conclusion: The SMILE technique was demonstrated to be an effective, predictable, safe, and stable technique in the treatment of moderate-to-severe myopia during the 24-month follow-up. Long-term follow-up should be undertaken to observe possible refractive regressions
Use of a new enrichment nanosorbent for speciation of mercury by FI-CV-ICP-MS
Mercury is one of the most toxic environmental pollutants and its effects on human and ecosystem health are well known. All mercury species are toxic, with organic mercury compounds generally being more toxic than inorganic species. Chromatography techniques (GC, HPLC) coupled to element specific detectors, are able to separate mercury species in order to elucidate mercury transformation and transport processes where the determination of all mercury species is desirable. However, in practice, especially in sampling campaigns for sea water analysis where a large number of samples are collected over a longer period of time, a combination of methods is usually applied to accurately determine the most toxic mercury species. These include non-chromatographic methods based on the different chemical and/or physical behavior of the mercury species. These non-chromatographic methods can be less time consuming, more cost effective and available, and present competitive limits of detection. Especially when mercury could vapor (CV) generation technique is employed, which reduces salt effect on the analytical signal and improve the sensibility. Among non-chromatographic methods, solid phase extraction and microextraction (SPE and SPME) which is becoming increasingly popular for sample preparation in organic analysis, found its way to speciation analysis of organometals. SPE/SPME is the most popular sample preconcentration method for its simplicity, high enrichment factor, low or no consumption of organic solvents and feasibly to be automated. On the other hand, the exploration of new materials, especially nanometer sized materials, as the support phase is another active research area in SPE/SPME for mercury determination. The use of nanoparticles leads to higher extraction capacity/efficiency and rapid dynamics of extraction originated from the higher surface area to volume ratio and short diffusion route.
In this work, a new enrichment nanosorbent functionalized with 1,5 bis (2-pyridyl) methylene thiocarbohidrazide was synthesized and characterized. From the study of its adsorption capacity toward metal ions, Hg2+ was observed to be one of the most retained 173.1 µmol g-1 at pH 5. Thus, a flow injection solid phase extraction and cold vapor generation method for its determination and speciation based on the use of this new chelating nanosorbent was optimized. The method developed has showed to be useful for the automatic pre-concentration and sequential speciation of mercury and methylmercury in environmental and biological samples. The system was based on chelating retention of the analytes onto a mini-column filled with the new nanosorbent and their sequential elution by using two different eluents, 0.2 % HCl for CH3Hg+ and 0.1 % thiourea in 0.5 % HCl for Hg2+. The determination was performed using inductively coupled plasma mass spectrometry. Under the optimum conditions and 120 s preconcentration time, the enrichment factors were 4.7 and 11.0; the detection limits (3σ) were 0.002 and 0.004 µg L-1; the determination limits (10σ) were 0.011 and 0.024 µg L-1; and the precisions (calculated for 10 replicate determinations at a 2 µg L-1 standard of both species) were 2.8 and 2.6 % (RSD); for CH3Hg+ and Hg2+, respectively. Linear calibration graphs were obtained for both species from the determination limits to at least 70 µg L-1. For the quality control of the analytical performance and the validation of the newly developed method, the analysis of two certified samples, LGC 6016 estuarine water and SRM 2976 mussel tissue were addressed. The results showed good agreement with the certified values. The method was successfully applied to the speciation of mercury in sea-water samples collected in the Málaga Bay.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Heterogeneous catalysis for the extraction of arabinoxylans from wheat bran
Introduction
The conversion of biomass within biorefineries into chemicals and energy is seen as a real possibility for the substitution of fossil resources. Raw materials of high lignocellulosic content are an interesting option. Besides wood and non-food crops, agricultural residues like straw and corn stover as well as other by-products of various origins are of high interest as feedstocks. Wheat bran represents such a by-product, which accrues in enormous quantities during the production of white wheat flour. It is estimated that 150 million tons are produced per year worldwide [1]. Currently wheat bran is mainly used as a low value ingredient in animal feed. Arabinoxylans are the most abundant structural polysaccharides in wheat bran, and they can be suitable compounds for the production of sugar alcohols. In general terms, the conversion of these hemicellulosic components from biomass into sugar alcohols is a two‑step reaction: 1) extraction and hydrolysis of arabinoxylans and 2) hydrogenation of these hemicelluloses into polyols (Figure 1).
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