Effects of air pollution on asthma hospitalization rates in different age groups in metropolitan cities of Korea

Many studies have shown relationships between air pollution and the rate of hospital admissions for asthma. A few studies have controlled for age-specific effects by adding separate smoothing functions for each age group. However, it has not yet been reported whether air pollution effects are significantly different for different age groups. This lack of information is the motivation for this study, which tests the hypothesis that air pollution effects on asthmatic hospital admissions are significantly different by age groups. Each air pollutant's effect on asthmatic hospital admissions by age groups was estimated separately. In this study, daily time-series data for hospital admission rates from seven cities in Korea from June 1999 through 2003 were analyzed. The outcome variable, daily hospital admission rates for asthma, was related to five air pollutants which were used as the independent variables, namely particulate matter <10 micrometers (μm) in aerodynamic diameter (PM10), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), and sulfur dioxide (SO2). Meteorological variables were considered as confounders. Admission data were divided into three age groups: children (<15 years of age), adults (ages 15-64), and elderly (≥ 65 years of age). The adult age group was considered to be the reference group for each city. In order to estimate age-specific air pollution effects, the analysis was separated into two stages. In the first stage, Generalized Additive Models (GAMs) with cubic spline for smoothing were applied to estimate the age-city-specific air pollution effects on asthmatic hospital admission rates by city and age group. In the second stage, the Bayesian Hierarchical Model with non-informative prior which has large variance was used to combine city-specific effects by age groups. The hypothesis test showed that the effects of PM10, CO and NO2 were significantly different by age groups. Assuming that the air pollution effect for adults is zero as a reference, age-specific air pollution effects were: -0.00154 (95% confidence interval(CI)= (-0.0030,-0.0001)) for children and 0.00126 (95% CI = (0.0006, 0.0019)) for the elderly for PM 10; -0.0195 (95% CI = (-0.0386,-0.0004)) for children for CO; and 0.00494 (95% CI = (0.0028, 0.0071)) for the elderly for NO2. Relative rates (RRs) were 1.008 (95% CI = (1.000-1.017)) in adults and 1.021 (95% CI = (1.012-1.030)) in the elderly for every 10 μg/m3 increase of PM10 , 1.019 (95% CI = (1.005-1.033)) in adults and 1.022 (95% CI = (1.012-1.033)) in the elderly for every 0.1 part per million (ppm) increase of CO; 1.006 (95%CI = (1.002-1.009)) and 1.019 (95%CI = (1.007-1.032)) in the elderly for every 1 part per billion (ppb) increase of NO2 and SO2, respectively. Asthma hospital admissions were significantly increased for PM10 and CO in adults, and for PM10, CO, NO2 and SO2 in the elderly.^

Cancer perceptions: Implications from the 2007 Health Information National Trends Survey

Background. Research has demonstrated associations between sociodemographic characteristics and illness perceptions; however, the impact of cancer exposure through personal or family diagnoses is not well-studied. The purposes of this study were to examine the prevalence of different cancer beliefs and the disparity in cancer beliefs across groups of individuals with distinct cancer histories; and to identify whether, when adjusted for sociodemographic characteristics, cancer history predicts a set of cancer beliefs.^ Methods. Using Leventhal’s Common Sense Model and data from the 2007 Health Information National Trends Survey (N=7172), we constructed multivariable logistic regressions to evaluate the effect of different stimuli, including cancer experience, on cancer perceptions (e.g., risk, worry, causation, outcome).^ Results. Findings indicate significant associations between cancer history and cancer perceptions. Individuals with family and personal cancer histories were more likely than individuals without any cancer history to worry about getting cancer (OR=3.55, P<0.01), agree they will develop cancer in the future (OR=8.81, P<0.01), and disagree that cancer is most often caused by a person’s behavior or lifestyle (OR=1.24, P=0.03). Additionally, results support education’s role in forming cancer perceptions. Individuals with high levels of education were more likely to endorse cancer prevention (OR=1.68, P<0.01) and higher 5-year survival rates (OR=1.41, P<0.01). ^ Conclusions. Results indicate cancer history affects cancer perceptions throughout the cancer continuum. Additionally, cancer history may influence coping behaviors and outcomes related to cancer.^ Impact. Cancer education and survivorship programs should assess important variables (e.g., cancer history) to more effectively tailor services and monitor evolving needs throughout cancer care.^

AN ANALYSIS OF THE RELATIVE INFLUENCE OF RACE, INCOME, EDUCATION, AND FOOD STAMP PROGRAM PARTICIPATION/NONPARTICIPATION ON THE FOOD AND NUTRIENT CONSUMPTION OF A NORTH FLORIDA URBAN CLINIC POPULATION IN CONJUNCTION WITH A SURVEY OF NUTRITION RELATED HABITS AND ATTITUDES

The relative influence of race, income, education, and Food Stamp Program participation/nonparticipation on the food and nutrient intake of 102 fecund women ages 18-45 years in a Florida urban clinic population was assessed using the technique of multiple regression analysis. Study subgroups were defined by race and Food Stamp Program participation status. Education was found to have the greatest influence on food and nutrient intake. Race was the next most influential factor followed in order by Food Stamp Program participation and income. The combined effect of the four independent variables explained no more than 19 percent of the variance for any of the food and nutrient intake variables. This would indicate that a more complex model of influences is needed if variations in food and nutrient intake are to be fully explained.^ A socioeconomic questionnaire was administered to investigate other factors of influence. The influence of the mother, frequency and type of restaurant dining, and perceptions of food intake and weight were found to be factors deserving further study.^ Dietary data were collected using the 24-hour recall and food frequency checklist. Descriptive dietary findings indicated that iron and calcium were nutrients where adequacy was of concern for all study subgroups. White Food Stamp Program participants had the greatest number of mean nutrient intake values falling below the 1980 Recommended Dietary Allowances (RDAs). When Food Stamp Program participants were contrasted to nonparticipants, mean intakes of six nutrients (kilocalories, calcium, iron, vitamin A, thiamin, and riboflavin) were below the 1980 RDA compared to five mean nutrient intakes (kilocalories, calcium, iron, thiamin and riboflavin) for the nonparticipants. Use of the Index of Nutritional Quality (INQ), however, revealed that the quality of the diet of Food Stamp Program participants per 1000 kilocalories was adequate with exception of calcium and iron. Intakes of these nutrients were also not adequate on a 1000 kilocalorie basis for the nonparticipant group. When mean nutrient intakes of the groups were compared using Student's t-test oleicacid intake was the only significant difference found. Being a nonparticipant in the Food Stamp Program was found to be associated with more frequent consumption of cookies, sweet rolls, doughnuts, and honey. The findings of this study contradict the negative image of the Food Stamp Program participant and emphasize the importance of education. ^

PROJECTION OF HEALTH DEMAND IN TERMS OF HOSPITAL ADMISSIONS FOR SELECTED DIAGNOSES IN HEALTH SYSTEMS AGENCY SERVICE AREAS

The National Health Planning and Resources Development Act of 1974 (Public Law 93-641) requires that health systems agencies (HSAs) plan for their health service areas by the use of existing data to the maximum extent practicable. Health planning is based on the identificaton of health needs; however, HSAs are, at present, identifying health needs in their service areas in some approximate terms. This lack of specificity has greatly reduced the effectiveness of health planning. The intent of this study is, therefore, to explore the feasibility of predicting community levels of hospitalized morbidity by diagnosis by the use of existing data so as to allow health planners to plan for the services associated with specific diagnoses.^ The specific objectives of this study are (a) to obtain by means of multiple regression analysis a prediction equation for hospital admission by diagnosis, i.e., select the variables that are related to demand for hospital admissions; (b) to examine how pertinent the variables selected are; and (c) to see if each equation obtained predicts well for health service areas.^ The existing data on hospital admissions by diagnosis are those collected from the National Hospital Discharge Surveys, and are available in a form aggregated to the nine census divisions. When the equations established with such data are applied to local health service areas for prediction, the application is subject to the criticism of the theory of ecological fallacy. Since HSAs have to rely on the availability of existing data, it is imperative to examine whether or not the theory of ecological fallacy holds true in this case.^ The results of the study show that the equations established are highly significant and the independent variables in the equations explain the variation in the demand for hospital admission well. The predictability of these equations is good when they are applied to areas at the same ecological level but become poor, predominantly due to ecological fallacy, when they are applied to health service areas.^ It is concluded that HSAs can not predict hospital admissions by diagnosis without primary data collection as discouraged by Public Law 93-641. ^

Prevalence and risk factors of asthma and work -related asthma among U.S. adults: Data from the Third National Health and Nutrition Examination Survey, 1988--1994

This cross-sectional analysis of the data from the Third National Health and Nutrition Examination Survey was conducted to determine the prevalence and determinants of asthma and wheezing among US adults, and to identify the occupations and industries at high risk of developing work-related asthma and work-related wheezing. Separate logistic models were developed for physician-diagnosed asthma (MD asthma), wheezing in the previous 12 months (wheezing), work-related asthma and work-related wheezing. Major risk factors including demographic, socioeconomic, indoor air quality, allergy, and other characteristics were analyzed. The prevalence of lifetime MD asthma was 7.7% and the prevalence of wheezing was 17.2%. Mexican-Americans exhibited the lowest prevalence of MD asthma (4.8%; 95% confidence interval (CI): 4.2, 5.4) when compared to other race-ethnic groups. The prevalence of MD asthma or wheezing did not vary by gender. Multiple logistic regression analysis showed that Mexican-Americans were less likely to develop MD asthma (adjusted odds ratio (ORa) = 0.64, 95%CI: 0.45, 0.90) and wheezing (ORa = 0.55, 95%CI: 0.44, 0.69) when compared to non-Hispanic whites. Low education level, current and past smoking status, pet ownership, lifetime diagnosis of physician-diagnosed hay fever and obesity were all significantly associated with MD asthma and wheezing. No significant effect of indoor air pollutants on asthma and wheezing was observed in this study. The prevalence of work-related asthma was 3.70% (95%CI: 2.88, 4.52) and the prevalence of work-related wheezing was 11.46% (95%CI: 9.87, 13.05). The major occupations identified at risk of developing work-related asthma and wheezing were cleaners; farm and agriculture related occupations; entertainment related occupations; protective service occupations; construction; mechanics and repairers; textile; fabricators and assemblers; other transportation and material moving occupations; freight, stock and material movers; motor vehicle operators; and equipment cleaners. The population attributable risk for work-related asthma and wheeze were 26% and 27% respectively. The major industries identified at risk of work-related asthma and wheeze include entertainment related industry; agriculture, forestry and fishing; construction; electrical machinery; repair services; and lodging places. The population attributable risk for work-related asthma was 36.5% and work-related wheezing was 28.5% for industries. Asthma remains an important public health issue in the US and in the other regions of the world. ^

Isotopic signature of specific biomarkers derived from anaerobic methanotrophic archaea (ANME groups) and sulphate-reducing bacteria (SRB) at different cold seep provinces

Anaerobic methane-oxidizing microbial communities in sediments at cold methane seeps are important factors in controlling methane emission to the ocean and atmosphere. Here, we investigated the distribution and carbon isotopic signature of specific biomarkers derived from anaerobic methanotrophic archaea (ANME groups) and sulphate-reducing bacteria (SRB) responsible for the anaerobic oxidation of methane (AOM) at different cold seep provinces of Hydrate Ridge, Cascadia margin. The special focus was on their relation to in situ cell abundances and methane turnover. In general, maxima in biomarker abundances and minima in carbon isotope signatures correlated with maxima in AOM and sulphate reduction as well as with consortium biomass. We found ANME-2a/DSS aggregates associated with high abundances of sn-2,3-di-O-isoprenoidal glycerol ethers (archaeol, sn-2-hydroxyarchaeol) and specific bacterial fatty acids (C16:1omega5c, cyC17:0omega5,6) as well as with high methane fluxes (Beggiatoa site). The low to medium flux site (Calyptogena field) was dominated by ANME-2c/DSS aggregates and contained less of both compound classes but more of AOM-related glycerol dialkyl glycerol tetraethers (GDGTs). ANME-1 archaea dominated deeper sediment horizons at the Calyptogena field where sn-1,2-di-O-alkyl glycerol ethers (DAGEs), archaeol, methyl-branched fatty acids (ai-C15:0, i-C16:0, ai-C17:0), and diagnostic GDGTs were prevailing. AOM-specific bacterial and archaeal biomarkers in these sediment strata generally revealed very similar d13C-values of around -100 per mill. In ANME-2-dominated sediment sections, archaeal biomarkers were even more 13C-depleted (down to -120 per mill), whereas bacterial biomarkers were found to be likewise 13C-depleted as in ANME-1-dominated sediment layers (d13C: -100 per mill). The zero flux site (Acharax field), containing only a few numbers of ANME-2/DSS aggregates, however, provided no specific biomarker pattern. Deeper sediment sections (below 20 cm sediment depth) from Beggiatoa covered areas which included solid layers of methane gas hydrates contained ANME-2/DSS typical biomarkers showing subsurface peaks combined with negative shifts in carbon isotopic compositions. The maxima were detected just above the hydrate layers, indicating that methane stored in the hydrates may be available for the microbial community. The observed variations in biomarker abundances and 13C-depletions are indicative of multiple environmental and physiological factors selecting for different AOM consortia (ANME-2a/DSS, ANME-2c/DSS, ANME-1) along horizontal and vertical gradients of cold seep settings.

Petrological parameters of sands and sandstones from DSDP and ODP holes in arc-related areas

Detrital modes for 524 deep-marine sand and sandstone samples recovered on circum-Pacific, Caribbean, and Mediterranean legs of the Deep Sea Drilling Project and the Ocean Drilling Program form the basis for an actualistic model for arc-related provenance. This model refines the Dickinson and Suczek (1979) and Dickinson and others (1983) models and can be used to interpret the provenance/tectonic history of ancient arc-related sedimentary sequences. Four provenance groups are defined using QFL, QmKP, LmLvLs, and LvfLvmiLvl ternary plots of site means: (1) intraoceanic arc and remnant arc, (2) continental arc, (3) triple junction, and (4) strike-slip-continental arc. Intraoceanic- and remnant-arc sands are poor in quartz (mean QFL%Q < 5) and rich in lithics (QFL%L > 75); they are predominantly composed of plagioclase feldspar and volcanic lithic fragments. Continental-arc sand can be more quartzofeldspathic than the intraoceanic- and remnant-arc sand (mean QFL%Q values as much as 10, mean QFL%F values as much as 65, and mean QmKP%Qm as much as 20) and has more variable lithic populations, with minor metamorphic and sedimentary components. The triple-junction and strike-slip-continental groups compositionally overlap; both are more quartzofeldspathic than the other groups and show highly variable lithic proportions, but the strike-slip-continental group is more quartzose. Modal compositions of the triple junction group roughly correlate with the QFL transitional-arc field of Dickinson and others (1983), whereas the strike-slip-continental group approximately correlates with their dissected-arc field.

Relative contents of principal diatom groups in suspended matter and surface layer bottom sediments from the Indian Ocean

Data on relative contents of principal diatom groups in suspended matter collected by a separator on the way of the ship and in bottom sediments from different areas of the Indian Ocean are presented in the paper.

Chemical composition of basalts and minerals from basalts of the Bouvet triple junction

This study focuses on mafic volcanic rocks from the Bouvet triple junction, which fall into six geochemically distinct groups: (1) N-MORB, the most widespread type, encountered throughout the study area. (2) Subalkaline volcanics, hawaiites and mugearites strongly enriched in lithophile elements and radiogenic isotopes and composing the Bouvet volcanic rise, and compositionally similar basalts and basaltic andesites from the Spiess Ridge, generated in a deeper, fertile mantle region. (3) Relatively weakly enriched basalts, T-MORB derived by the mixing of Type 1 and 2 melts and exposed near the axes of the Mid-Atlantic, Southwest Indian, and America-Antarctic Ridges. (4) Basalts with a degree of trace lithophile element enrichment similar to the Spiess Ridge and Bouvet Island rocks, but higher in K, P, Ti, and Cr. These occur within extensional structures: the rift valley of the Southwest Indian Ridge, grabens of the East Dislocation Zone, and the linear rise between the Spiess Ridge and Bouvet volcano. Their parental melts presumably separated from plume material that spread from the main channels and underwent fluid-involving differentiation in the mantle. (5) A volcanic suite ranging from basalt to rhyolite, characterized by low concentrations of lithophile elements, particularly TiO2, and occurring on the Shona Seamount and other compressional features within the Antarctic and South American plates near the Bouvet triple junction. Unlike Types 1 to 4, which display tholeiitic differentiation trends, this suite is calc-alkaline. Its parental melts were presumably related to the plume material as well but, subsequently, they underwent a profound differentiation involving fluids and assimilated surrounding rocks in closed magma chambers in the upper mantle. Alternatively, the Shona Seamount might be a fragment of an ancient oceanic island arc. (6) Enriched basalts, distinguished from the other enriched rock types in very high P and radiogenic isotope abundances and composing a tectonic uplift near the junction of the three rifts. It thus follows that the main factors responsible for the compositional diversity of volcanic rocks in this region include (i) mantle source heterogeneity, (ii) plume activity, (iii) an intricate geodynamic setup at the triple junction giving rise to stresses in adjacent plate areas, and (iv) the geological prehistory. The slow spreading rate and ensuing inefficient mixing of the heterogeneous mantle material result in strong spatial variations in basaltic compositions.

Building Trust for Lambda-Congenial Secret Groups

Establishing trust while preserving privacy is a challenging research problem. In this paper we introduce lambda -congenial secret groups which allow users to recognize trusted partners based on common attributes while preserving their anonymity and privacy. Such protocols are different from authentication protocols, since the latter are based on identities, while the former are based on attributes. Introducing attributes in trust establishment allows a greater flexibility but also brings up several issues. In this paper, we investigate the problem of building trust with attributes by presenting motivating examples, analyzing the security requirements and giving an informal definition. We also survey one of the most related techniques, namely private matching, and finally present solutions based on it.

Detection of growth-related QTLs in turbot (Scophtalmus maximux)

Background The turbot (Scophthalmus maximus) is a highly appreciated European aquaculture species. Growth related traits constitute the main goal of the ongoing genetic breeding programs of this species. The recent construction of a consensus linkage map in this species has allowed the selection of a panel of 100 homogeneously distributed markers covering the 26 linkage groups (LG) suitable for QTL search. In this study we addressed the detection of QTL with effect on body weight, length and Fulton's condition factor. Results Eight families from two genetic breeding programs comprising 814 individuals were used to search for growth related QTL using the panel of microsatellites available for QTL screening. Two different approaches, maximum likelihood and regression interval mapping, were used in order to search for QTL. Up to eleven significant QTL were detected with both methods in at least one family: four for weight on LGs 5, 14, 15 and 16; five for length on LGs 5, 6, 12, 14 and 15; and two for Fulton's condition factor on LGs 3 and 16. In these LGs an association analysis was performed to ascertain the microsatellite marker with the highest apparent effect on the trait, in order to test the possibility of using them for marker assisted selection. Conclusions The use of regression interval mapping and maximum likelihood methods for QTL detection provided consistent results in many cases, although the high variation observed for traits mean among families made it difficult to evaluate QTL effects. Finer mapping of detected QTL, looking for tightly linked markers to the causative mutation, and comparative genomics are suggested to deepen in the analysis of QTL in turbot so they can be applied in marker assisted selection programs.

Research activities of Spanish antenna groups

When we look at the history of electricity and electromagnetism in Spain we discover that the most important Spanish researchers are generally out of the official institutions or stable research groups until the 20th century [1] [2]. In the 20th century most of the scientific research is done in stable research institutions and universities and the most important electromagnetism research centres in Spain are located in the Faculty of Physics of the most important universities, the National Scientific Research Council (CSIC) and the School for Telecommunication Engineering created in 1923. But the greatest impulse of research in the antenna and radiowave propagation field is done after 1960 reaching the first national URSI conference in 1980. After that year, the relation between groups and the number of research groups is continuously growing and the relation to industry is also increasing. When Spain joins the European research organizations (COST, ERC...) and the European Union in 1985 the research support experience a fast growing and the participation in the European research structures. In the antenna design field, there exist some specializations although most of the groups have dome specific projects in almost all the antenna analysis and design fields. Here, we have selected the most important and characteristic area related to each of the research groups and institutions. The easiest way to classify the research work in antennas is the selection between antenna analysis, design and measurement. After that the selected frequency bands technology, the type of antennas and the related circuits can be a good criterion to describe the variety of research work and specialization between groups.

Leader Rural Development Program in Spain: Profile and Functions of Workers in Local Action Groups.

Occupations in the labor market are linked with to a minimum basic training and other capacities. Hired workers should be able to accomplish required functions related to their specific job. Regarding the rural development labor market, local action groups? workers have defined performance areas?projects, strategy, organization and training & market?but specific functions within each of these areas are not as clearly defined. Neither both, basic training and capacities needed to perform each job profile within the local action group are defined. This communication analyses training and other capacities linked to each of the job profiles within the local action group. Functions within each of the performance areas previously defined are also analyzed regarding the job profiles.

Fishing effort control regulations influence on stability, safety and operability of small fishing vessels: study of a series of stability related accidents occurred in Spain between 2004 and 2007

Entre los años 2004 y 2007 se hundieron por problemas de estabilidad cinco pesqueros españoles de pequeña eslora, de características parecidas, de relativamente poca edad, que habían sido construidos en un intervalo de pocos años. La mayoría de los tripulantes de esos pesqueros fallecieron o desaparecieron en esos accidentes. Este conjunto de accidentes tuvo bastante repercusión social y mediática. Entre ingenieros navales y marinos del sector de la pesca se relacionó estos accidentes con los condicionantes a los diseños de los pesqueros impuestos por la normativa de control de esfuerzo pesquero. Los accidentes fueron investigados y publicados sus correspondientes informes; en ellos no se exploró esta supuesta relación. Esta tesis pretende investigar la relación entre esos accidentes y los cambios de la normativa de esfuerzo pesquero. En la introducción se expone la normativa de control de esfuerzo pesquero analizada, se presentan datos sobre la estructura de la flota pesquera en España y su accidentalidad, y se detallan los criterios de estabilidad manejados durante el trabajo, explicando su relación con la seguridad de los pesqueros. Seguidamente se realiza un análisis estadístico de la siniestralidad en el sector de la pesca para establecer si el conjunto de accidentes estudiados supone una anomalía, o si por el contrario el conjunto de estos accidentes no es relevante desde el punto de vista estadístico. Se analiza la siniestralidad a partir de diversas bases de datos de buques pesqueros en España y se concluye que el conjunto de accidentes estudiados supone una anomalía estadística, ya que la probabilidad de ocurrencia de los cinco sucesos es muy baja considerando la frecuencia estimada de pérdidas de buques por estabilidad en el subsector de la flota pesquera en el que se encuadran los cinco buques perdidos. A continuación el trabajo se centra en la comparación de los buques accidentados con los buques pesqueros dados de baja para construir aquellos, según exige la normativa de control de esfuerzo pesquero; a estos últimos buques nos referiremos como “predecesores” de los buques accidentados. Se comparan las dimensiones principales de cada buque y de su predecesor, resultando que los buques accidentados comparten características de diseño comunes que son sensiblemente diferentes en los buques predecesores, y enlazando dichas características de diseño con los requisitos de la nueva normativa de control del esfuerzo pesquero bajo la que se construyeron estos barcos. Ello permite establecer una relación entre los accidentes y el mencionado cambio normativo. A continuación se compara el margen con que se cumplían los criterios reglamentarios de estabilidad entre los buques accidentados y los predecesores, encontrándose que en cuatro de los cinco casos los predecesores cumplían los criterios de estabilidad con mayor holgura que los buques accidentados. Los resultados obtenidos en este punto permiten establecer una relación entre el cambio de normativa de esfuerzo pesquero y la estabilidad de los buques. Los cinco buques accidentados cumplían con los criterios reglamentarios de estabilidad en vigor, lo que cuestiona la relación entre esos criterios y la seguridad. Por ello se extiende la comparativa entre pesqueros a dos nuevos campos relacionados con la estabilidad y la seguridad delos buques: • Movimientos a bordo (operatividad del buque), y • Criterios de estabilidad en condiciones meteorológicas adversas El estudio de la operatividad muestra que los buques accidentados tenían, en general, una mayor operatividad que sus predecesores, contrariamente a lo que sucedía con el cumplimiento de los criterios reglamentarios de estabilidad. Por último, se comprueba el desempeño de los diez buques en dos criterios específicos de estabilidad en caso de mal tiempo: el criterio IMO de viento y balance intenso, y un criterio de estabilidad de nueva generación, incluyendo la contribución original del autor de considerar agua en cubierta. Las tendencias observadas en estas dos comparativas son opuestas, lo que permite cuestionar la validez del último criterio sin un control exhaustivo de los parámetros de su formulación, poniendo de manifiesto la necesidad de más investigaciones sobre ese criterio antes de su adopción para uso regulatorio. El conjunto de estos resultados permite obtener una serie de conclusiones en la comparativa entre ambos conjuntos de buques pesqueros. Si bien los resultados de este trabajo no muestran que la aprobación de la nueva normativa de esfuerzo pesquero haya significado una merma general de seguridad en sectores enteros de la flota pesquera, sí se concluye que permitió que algunos diseños de buques pesqueros, posiblemente en busca de la mayor eficiencia compatible con dicha normativa, quedaran con una estabilidad precaria, poniendo de manifiesto que la relación entre seguridad y criterios de estabilidad no es unívoca, y la necesidad de que éstos evolucionen y se adapten a los nuevos diseños de buques pesqueros para continuar garantizando su seguridad. También se concluye que la estabilidad es un aspecto transversal del diseño de los buques, por lo que cualquier reforma normativa que afecte al diseño de los pesqueros o su forma de operar debería estar sujeta a evaluación por parte de las autoridades responsables de la seguridad marítima con carácter previo a su aprobación. ABSTRACT Between 2004 and 2007 five small Spanish fishing vessels sank in stability related accidents. These vessels had similar characteristics, had relatively short age, and had been built in a period of a few years. Most crewmembers of these five vessels died or disappeared in those accidents. This set of accidents had significant social and media impact. Among naval architects and seamen of the fishing sector these accidents were related to the design constraints imposed by the fishing control effort regulations. The accidents were investigated and the official reports issued; this alleged relationship was not explored. This thesis aims to investigate the relationship between those accidents and changes in fishing effort control regulations. In the introduction, the fishing effort control regulation is exposed, data of the Spanish fishing fleet structure and its accident rates are presented, and stability criteria dealt with in this work are explained, detailing its relationship with fishing vessel safety. A statistical analysis of the accident rates in the fishing sector in Spain is performed afterwards. The objective is determining whether the set of accidents studied constitute an anomaly or, on the contrary, they are not statistically relevant. Fishing vessels accident rates is analyzed from several fishing vessel databases in Spain. It is concluded that the set of studied accidents is statistically relevant, as the probability of occurrence of the five happenings is extremely low, considering the loss rates in the subsector of the Spanish fishing fleet where the studied vessels are fitted within. From this point the thesis focuses in comparing the vessels lost and the vessels that were decommissioned to build them as required by the fishing effort control regulation; these vessels will be referred to as “predecessors” of the sunk vessels. The main dimensions between each lost vessel and her predecessor are compared, leading to the conclusion that the lost vessels share design characteristics which are sensibly different from the predecessors, and linking these design characteristics with the requirements imposed by the new fishing control effort regulations. This allows establishing a relationship between the accidents and this regulation change. Then the margin in fulfilling the regulatory stability criteria among the vessels is compared, resulting, in four of the five cases, that predecessors meet the stability criteria with greater clearance than the sunk vessels. The results obtained at this point would establish a relationship between the change of fishing effort control regulation and the stability of vessels. The five lost vessels complied with the stability criteria in force, so the relation between these criteria and safety is put in question. Consequently, the comparison among vessels is extended to other fields related to safety and stability: • Motions onboard (operability), and • Specific stability criteria in rough weather The operability study shows that the lost vessels had in general greater operability than their predecessors, just the opposite as when comparing stability criteria. Finally, performance under specific rough weather stability criteria is checked. The criteria studied are the IMO Weather Criterion, and one of the 2nd generation stability criteria under development by IMO considering in this last case the presence of water on deck, which is an original contribution by the author. The observed trends in these two cases are opposite, allowing to put into question the last criterion validity without an exhaustive control of its formulation parameters; indicating that further research might be necessary before using it for regulatory purposes. The analysis of this set of results leads to some conclusions when comparing both groups of fishing vessels. While the results obtained are not conclusive in the sense that the entry into force of a new fishing effort control in 1998 caused a generalized safety reduction in whole sectors of the Spanish fishing fleet, it can be concluded that it opened the door for some vessel designs resulting with precarious stability. This evidences that the relation between safety and stability criteria is not univocal, so stability criteria needs to evolve for adapting to new fishing vessels designs so their safety is still guaranteed. It is also concluded that stability is a transversal aspect to ship design and operability, implying that any legislative reform affecting ship design or operating modes should be subjected to assessing by the authorities responsible for marine safety before being adopted.