364 research outputs found
What do shrimper trawlers fish in North West Africa? The issue of discards
In compliance with the Regulation ( 2017 1004 of the European Parliament and of the Council of 17 May 2017 on the establishment of a Union framework for the collection, management and use of data in the fisheries sector and support for scientific advice regarding the common fisheries policy (Data Collection Framework, DCF), Spain performs a monitoring program through scientific observations onboard the Spanish shrimper fishery operating in Mauritanian waters.The Spanish shrimper trawlers fishing off Mauritanian waters usually alternate the use of two different gears, depending on the target species. Outriggers are used to fish Parapenaeus longirostris and Penaeus notialis usually during daylight hauls and the classic bottom otter trawl with trawl doors baka type) is employed for a deeper fishery, especially targeting Aristeus varidens These last deep hauls are usually made at night. This fishery is characterized by capturing a great diversity of species three target species, other retained species and a significant amount of species that end up back in the sea, discard
The structure of the class of maximum tsallis-havrda-chavat entropy copulas
A maximum entropy copula is the copula associated with the joint distribution, with prescribed marginal distributions on [0, 1], which maximizes the Tsallis-Havrda-Chavat entropy with q = 2. We find necessary and sufficient conditions for each maximum entropy copula to be a copula in the class introduced in Rodriguez-Lallena and Ubeda-Flores (2004), and we also show that each copula in that class is a maximum entropy copula.A maximum entropy copula is the copula associated with the joint distribution, with prescribed marginal distributions on [0, 1], which maximizes the Tsallis-Havrda-Chavat entropy with q = 2. We find necessary and sufficient conditions for each maximum entropy copula to be a copula in the class introduced in Rodriguez-Lallena and Ubeda-Flores (2004), and we also show that each copula in that class is a maximum entropy copula.18
Interdecadal variability of Southeastern South America rainfall and moisture sources during the austral summertime
Sea surface temperature (SST) anomalies over the tropical oceans are able to generate extratropical atmospheric circulation anomalies that can induce rainfall variability and changes in the sources of moisture. The work reported here evaluates the interdecadal changes in the moisture sources for southeastern South America (SESA) during austral summer, and it is divided into two complementary parts. In the first part the authors construct a climate network to detect synchronization periods among the tropical oceans and the precipitation over SESA. Afterward, taking into account these results, the authors select two periods with different degrees of synchronization to compare the spatial distribution of the SESA moisture sources. Results show that during the last century there were three synchronization periods among the tropical oceans and the precipitation over SESA (during the 1930s, 1970s, and 1990s) and suggest that the main moisture sources of SESA are the recycling over the region, the central-eastern shore of Brazil together with the surrounding Atlantic Ocean, and the southwestern South Atlantic surrounding the SESA domain. Comparison of SESA moisture sources for the 1980s (a period of nonsignificant synchronization) and the 1990s (a synchronized period) shows that the principal differences are in the intensity of the recycling and in the strength of the central-eastern shore of Brazil. Moreover, the authors find that a region centered at (20°S, 300°E) is a moisture source for SESA only during the 1990s. These differences can be associated with the development of a low-level anticyclonic (cyclonic) anomaly circulation over central-eastern Brazil that favors the transport of moisture from central Brazil (central-eastern shore of Brazil) toward SESA in the 1990s (1980s
Biomarkers in ocular chronic graft versus host disease: tear cytokine- and chemokine-based predictive model.
Producción CientíficaPurpose: To develop a tear molecule level-based predictive model based on a panel of tear cytokines and their correlation with clinical features in ocular chronic graft versus host disease (cGVHD).
Methods: Twenty-two ocular cGVHD patients and 21 healthy subjects were evaluated in a controlled environmental research laboratory (CERLab). Clinical parameters were recorded, and tears were collected. Levels of 15 molecules (epidermal growth factor [EGF], IL receptor antagonist [IL-1Ra], IL-1β, IL-2, IL-6, IL-8/CXCL8, IL-10, IL-12p70, IL-17A, interferon inducible protein [IP]-10/CXCL10, IFN-γ, VEGF, TNF-α, eotaxin 1, and regulated on activation normal T cell expressed and secreted [RANTES]) were measured by multiplex-bead assay and correlated with clinical parameters. Logistic regression was used to develop a predictive model. Leave-one-out cross-validation was applied. Classification capacity was evaluated in a cohort of individuals with dry eye (DE) of other etiologies different from GVHD.
Results: Epidermal growth factor and IP-10/CXCL10 levels were significantly decreased in ocular cGVHD, positively correlating with tear production and stability and negatively correlating with symptoms, hyperemia, and vital staining. Interleukin-1Ra, IL-8/CXCL8, and IL-10 were significantly increased in ocular cGVHD, and the first two correlated positively with symptoms, hyperemia, and ocular surface integrity while negatively correlating with tear production and stability. Predictive models were generated, and the best panel was based on IL-8/CXCL8 and IP-10/CXCL10 tear levels along with age and sex, with an area under the receiving operating curve of 0.9004, sensitivity of 86.36%, and specificity of 95.24%.
Conclusions: A predictive model based on tear levels of IL-8/CXCL8 and IP-10/CXCL10 resulted in optimal sensitivity and specificity. These results add further knowledge to the search for potential biomarkers in this devastating ocular inflammatory disease.Ministry of Economy and Competitiveness, Madrid, Spain, SAF-2010 15631 (AES)
Discards from a deep-sea shrimp fishery in Angolan waters (SW Africa)
A programme of observers on board Spanish shrimp trawlers in Angola was initiated by IEO in 2018 in order to improve the scientific information required by Sustainable Management of External Fishing Fleets (SMEFF Regulation of the EU). In this context, discard studies are considered very relevant, both for assessment purposes and for obtaining information on adverse ecological impacts in marine ecosystems. Most fishing hauls performed during the observed period November 2018 to December 2019 were carried out at depths between 384 and 649 m, with classic bottom otter trawl targeting the striped red shrimp Aristeus varidens. Discards accounted for 60% of the total catch during the analysed period. The estimated global discard rate for 2019 (2.2 discard/retained catch) indicates that 1915 tonnes of retained catch produced 4213 tonnes of discards, of which a small amount is of commercial species, as A. varidens (3.8 tonnes) and Merluccius polli (153 tonnes). A total of 131 discarded species were identified, with the highest group contribution being fish (70%), followed by crustaceans (20%). The most abundant species in discard weight were Ariomma melanum, Lamprogrammus exutus, Chaunax pictus, Centroscymnus owstonii, Hoplostethus cadenati, Lophius vaillanti, Yarrella blackfordi and Ariomma bondi (all together accounting for 55% of discards). The most frequent species were H. cadenati and L. exutus, discarded in 95% of the analysed fishing hauls. Discards estimations of commercial species obtained through a long-term observers program might result in improving the assessments of main commercial species from Angolan deep sea waters
Discard and by-catch of the shrimper fleet in a West African fishing ground: towards an Ecosystem Approach to Fisheries Management.
It is widely recognized that discards and overexploitation produced by intense fishing activities are not only a risk for fisheries sustainability but also the cause of the marine resources decline, this involving significant changes in the trophic webs and habitats. This is especially the case of bottom trawl fisheries, and more specifically shrimp trawls, which produce average discards that can be higher than 70% of catches.
A Spanish shrimp fishery has been traditionally developed in West African fishing grounds, being especially relevant in Mauritanian waters, due to their high productivity. Since 2010, discards produced by this fishery have been studied from the information obtained through a “Program of scientific observers onboard” carried out by the Spanish Institute of Oceanography (IEO). Two annual observation cycles (2010 and 2014) have been conducted in Mauritania, giving information on catches and discards from a total of 996 (2014) and 1143 hauls (2010). More than 250 species were identified in the discards produced by this fleet. Cluster analyses and multidimensional scaling (MDS) revealed the occurrence of three well-defined assemblages, related to the depth fishery of the three main target species: one coastal shelf assemblage, in fishing depths of the southern pink shrimp Penaeus notialis (30-60 m depth), one slope assemblage in fishing depths of the deep-water rose shrimp Parapenaeus longirostris (90-300 m) and a deep slope assemblage in fishing depths of the striped red shrimp Aristeus varidens (300-900 m). The structure of each assemblage is presented in this work.
Quantifying the bycatch and discard and identifying the main species are key steps to address a solution to effectively reduce their effects and to maintain healthy marine ecosystems.Fondo Europeo Marítimo y de Pesca (FEMP
Antioxidant and angiotensin I-converting enzyme (ACE) inhibitory peptides of rainbow trout (Oncorhynchus mykiss) viscera hydrolysates subjected to simulated gastrointestinal digestion and intestinal absorption
The objective of this work was to evaluate in vitro bioaccessibility, intestinal absorption, antioxidant and angiotensin I-converting enzyme (ACE) inhibitory activities of peptides from rainbow trout viscera hydrolysate (H). Rainbow trout Viscera (V) was hydrolyzed by Alcalase® 2.4L and a degree of hydrolysis (DH) of 44.8 ± 2.5% was achieved. Viscera and its hydrolysate were subjected to simulated gastrointestinal digestion (SGID) and intestinal absorption across Caco-2/TC7 cell monolayers. After the hydrolysis with Alcalase® 2.4L and the SGID of V, the species between 60.6 kDa and 13.0 kDa were decreased, causing an increase in species less than 6.51 kDa. The SGID of H did not modify the oxygen radical absorbance capacity (ORAC) or ACE inhibitory values but caused a significant decrease in the hydroxyl radical antioxidant capacity (HORAC) (30.2%). It also produced an increase in ABTS radical cation (ABTS assay) scavenging activity and ferric reducing antioxidant power (FRAP) (9.46% and 20.2%, respectively). Bioactive peptides in H were stable after SGID and they were partially able to cross Caco-2/TC7 cell monolayer, which demonstrates their possible intestinal absorption and their potential to act inside the organism.Fil: Vásquez, Priscilla. Universidad de Antioquia. Facultad de Ciencias Farmaceuticas y Alimentarias. Departamento de Alimentos; ColombiaFil: Zapata, José E.. Universidad de Antioquia. Facultad de Ciencias Farmaceuticas y Alimentarias. Departamento de Alimentos; ColombiaFil: Chamorro, Verónica C.. Instituto Nacional de Tecnología Agropecuaria; ArgentinaFil: García Fillería, Susan Fiorella. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Tironi, Valeria Anahi. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentin
Growth of the deep water rose shrimp Parapenaeus longirostris in Mauritanian waters (NW Africa)
The deep water rose shrimp Parapenaeus longirostris is the main target species of a Spanish fleet of shrimp bottom trawlers operating in the Mauritanian EEZ. The life history of this species is well known in north eastern Atlantic and Mediterranean waters, while the information is quite limited for the eastern central Atlantic. Biological samplings of the species were conducted by scientific observers onboard this fleet, from catches obtained during 17 fishing trips performed between March 2014 and June 2019. The carapace lengths (CL) of 91662 specimens (54% females and 46% males) were grouped in 33 monthly length frequency distributions. For the study of the length–age relationship, the Von Bertalanffy Growth Function (VBGF) was fit to the monthly length distributions by using the ELEFAN I routine followed by separating the frequency histograms into normal components through the Bhattacharya’s method and the NORMSEP routine. These analyses were carried out separately for males, females, and combined sexes, using the FISAT II automatic calculation program. CL of females and males ranged from 11.6 to 39.2 mm and 10.5 to 30.5 mm, respectively. Three and five modal components (annual cohorts) were identified for females and males, respectively. The growth function estimated parameters were CL∞=41.74, k=0.51 for combined sexes, CL∞= 41.67, k= 0.51 for females and CL∞= 32.24, k=0.84 for males. Estimated growth performance indices were around 2.95 for combined sexes, females and males. The estimated parameters may be used as input to test length-based methodologies for the assessment of this data-limited stock, for which only production models have been used so far
Revisión de resultados experimentales en técnicas de prueba y de educción de conocimientos
La cantidad de experimentos realizados en el ámbito de la ingeniería del software ha ido aumentando considerablemente en los últimos años. Estos experimentos cubren un amplio rango de temas, como por ejemplo, técnicas de pruebas en software, técnicas de educción de conocimientos, lenguajes de programación, etc. Sin embargo, si los experimentos no son tratados como investigaciones controladas, formales y rigurosas, existe un riesgo de obtener conclusiones que carezcan de validez.
En este reporte, se analizan 32 experimentos sobre técnicas de prueba y de educción de conocimientos para verificar la correctitud de los mismos.
En la sección 2, se describe el estado de la cuestión, donde se exponen nociones de experimentación y técnicas estadísticas. La sección 3, describe el problema a tratar; y la sección 4, la solución propuesta. Los resultados se exponen en la sección 5. En la sección 6, se presentan las conclusiones, seguidas por las futuras líneas de investigación y la bibliografía en las secciones 7 y 8 respectivamente.Eje: Ingeniería de Software y Base de DatosRed de Universidades con Carreras en Informática (RedUNCI
Revisión de resultados experimentales en técnicas de prueba y de educción de conocimientos
La cantidad de experimentos realizados en el ámbito de la ingeniería del software ha ido aumentando considerablemente en los últimos años. Estos experimentos cubren un amplio rango de temas, como por ejemplo, técnicas de pruebas en software, técnicas de educción de conocimientos, lenguajes de programación, etc. Sin embargo, si los experimentos no son tratados como investigaciones controladas, formales y rigurosas, existe un riesgo de obtener conclusiones que carezcan de validez.
En este reporte, se analizan 32 experimentos sobre técnicas de prueba y de educción de conocimientos para verificar la correctitud de los mismos.
En la sección 2, se describe el estado de la cuestión, donde se exponen nociones de experimentación y técnicas estadísticas. La sección 3, describe el problema a tratar; y la sección 4, la solución propuesta. Los resultados se exponen en la sección 5. En la sección 6, se presentan las conclusiones, seguidas por las futuras líneas de investigación y la bibliografía en las secciones 7 y 8 respectivamente.Eje: Ingeniería de Software y Base de DatosRed de Universidades con Carreras en Informática (RedUNCI
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