230 research outputs found
Update of Albacore tag release-recapture information in the North-Atlantic and Mediterranean for the period 1968-1999
This paper updates and completes the ICCAT database on albacore tag release–recapture from the North Atlantic including the Mediterranean Sea. In this revision French tag release–
recapture data from the sixties and seventies is included, as well as additional information
obtained from existing bibliography.Le présent document actualise et complète la base de données de l'ICCAT sur le marquage et la
recapture de germon de l'Atlantique nord, Méditerranée comprise. Cette révision comporte des
données françaises de marquage/recapture des années 1960 et 1970, ainsi que des informations
additionnelles extraites de la bibliographie disponible.En el presente documento se actualiza y completa la base ICCAT de datos de marcadorecaptura
de atún blanco del Atlántico Norte, incluyendo el Mediterráneo. En esta revisión se
incluyen los datos de marcado-recaptura franceses de los años los años sesenta y setenta, así
como otras informaciones procedentes de revisiones bibliográficas
Characterization of Chemically Modified Human Amniotic Membranes for Tissue Engineering Applications
The human amniotic membrane (hAM) is a collagen-based extracellular matrix derived from the human placenta. It is a readily-available, inexpensive, and naturally biocompatible material. Despite its attractive biological and biochemical properties, the hAM has been restricted for some tissue engineering or regenerative medicine applications by its moderate mechanical properties and rapid biodegradation. In this work, the use of riboflavin, a water-soluble vitamin, is investigated to crosslink and strengthen the human amniotic membrane under UVA light. The effect of riboflavin-UVA crosslinking on hAM properties were determined via infrared spectroscopy, uniaxial tensile testing, proteolytic degradation, permeability testing, SEM, and quantification of free (un-crosslinked) amine groups. Improved hAM mechanical properties must not come at the expense of reduced cellular proliferation and induction capabilities. In this study were assessed the viability, proliferation, immunophenotype, and multilineage differentiation ability of human adipose-derived stem cells seeded on riboflavin-UVA crosslinked membranes. Overall, hAM crosslinked with riboflavin-UVA benefited from a stable 2.5-fold increase in mechanical properties and improved biodegradation, all while retaining their biocompatibility and abilities to support the cultivation and differentiation of adipose-derived stem cells. Together, these results suggest that riboflavin-UVA crosslinking is an effective strategy to enhance the hAM for potential cardiovascular and tendon tissue engineering applications. Additionally, porcine adipose-derived stem cells (pASCs) were identified as a reliable stem cell source thanks to their abundance, straightforward isolation, and broad differentiation abilities. Knowledge of the properties of pASCs is critical for the success of therapeutic studies in preclinical pig models. Finally, the construction of a simple mechanical testing apparatus using off-the-shelf materials and open-source software for a total cost of less than $100 is reported
Age-length keys availability for Atlantic bluefin tuna captured in the eastern management area
This paper analyzes the available direct ageing information in the last decade from Atlantic bluefin tuna caught in the eastern management area. To investigate differences among ALKs, a standard Von Bertalanffy growth function (VB) was fit to length at age data for each stratum. A deficient convergence of VB fitting to the asymptotic length due to the scarcity of old specimens was found for all available ALKs. After these analyses some records were identified as outliers (reading methodological issues) and removed from the data base.En prensa0,000
Estimating albacore movement rates between the North Atlantic and the Mediterraneal from conventional tagging data
A tag attrition model is fit to albacore tag-recapture data in order to estimate albacore movement
rates between the Atlantic and the Mediterranean. The estimated transfer rate from the Atlantic to
the Mediterranean is not significantly different from zero, and the estimated annual transfer rate
in the opposite direction, under the assumptions of the same catchability and reporting rates is
5,49%. Sensitivity tests to assumed reporting rates and relative catchabilities are performed, and
observed lower recovery rates in the Mediterranean may suggest either a lower catchability or
reporting rate in this area, that would give an even lower estimate of the transfer rate, which is
also supported by information from later tag recaptures of fish tagged in the Mediterranean. The
small impact of these transfer rates on stock assessment is discussed and a preliminary assessment
of the amount of tagged fish needed in order to get accurate and precise estimates of these low
transfer rates is also done by simulating different tagging scenarios.Un modèle de déperdition des marques est ajusté aux données de marquage-recapture du germon afin d’estimer les taux de déplacement du germon entre l’Atlantique et la Méditerranée.
Le taux de transfert estimé de l’Atlantique à la Méditerranée n’est pas sensiblement différent de
zéro, et le taux de transfert annuel estimé dans la direction opposée, en prenant comme postulat
une capturabilité et des taux de soumission de données identiques, s’élève à 5,49%. On a réalisé des tests de sensibilité aux taux de soumission de données supposés et à la capturabilité
relative. Les taux de récupération inférieurs observés en Méditerranée suggèrent
éventuellement une capturabilité ou un taux de soumission de données plus faible dans cette
zone, ce qui donnerait une estimation encore plus faible du taux de transfert. Cela est
également appuyé par des informations provenant de récupérations tardives de marques de
poissons marqués en Méditerranée. Le faible impact de ces taux de transfert sur l’évaluation du
stock est discuté et une évaluation préliminaire du volume de poissons marqués nécessaire pour
obtenir des estimations exactes et précises de ces faibles taux de transfert est également
réalisée en simulant différents scénarios de marquage.Se ajusta un modelo de tasa de pérdida de marcas a los datos de marcado-recuperación de
atún blanco con el fin de estimar las tasas de movimiento del atún blanco entre el Atlántico y el
Mediterráneo. La tasa de transferencia estimada del Atlántico al Mediterráneo no se diferencia
significativamente de cero, y la tasa de transferencia anual estimada en la dirección opuesta,
bajo el supuesto de la misma tasa de capturabilidad y comunicación, es de 5,49%. Se
realizaron pruebas de sensibilidad de las tasas de comunicación y capturabilidades relativas supuestas, y las tasas de recuperación inferiores observadas en el Mediterráneo pueden sugerir
una tasa de capturabilidad o de comunicación más baja en esta zona, lo que proporcionaría
una estimación aún más baja de transferencia, que se ve sustentada por la información de
recuperaciones de marcas posteriores de peces marcados en el Mediterráneo. Se discute el
bajo impacto de estas tasas de transferencia en la evaluación del stock y también se realiza una
evaluación preliminar de la cantidad de peces marcados necesarios para obtener estimaciones
precisas y exactas de estas bajas tasas de trasferencia mediante una simulación de diferentes
escenarios de marcado
Simplified screening approach of anabolic steroid esters using a compact atmospheric solid analysis probe mass spectrometric system
Due to the absence of chromatographic separation, ambient ionization mass spectrometry had the potential to improve the throughput of control laboratories in the last decades and will soon be an excellent approach for on-site use as well. In this study, an atmospheric solids analysis probe (ASAP) with a single quadrupole mass analyzer has been evaluated to identify anabolic steroid esters rapidly. Sample introduction, applied scan time, and probe temperature were optimized for sensitivity. The in-source fragmentations of seventeen selected steroid esters, commonly found in illicit samples, were determined by applying different cone voltages (12, 20, 30, and 40 V). A spectral library was created for these steroid esters based on the four stages of in-source fragmentation spectra. The applicability of this method was demonstrated for the rapid identification of steroid esters in oily injection solutions, providing test results in less than 2 min
Use of lectins to characterise genetic variability and geographic differentiation in natural populations of Thunnus alalunga (Bonn. 1788)
New tools from cell and molecular biology can be used to implement the knowledge of fish
biology and fisheries. In this sense, we suggest that the use of lectins can be an understandable
procedure to study population structure of fishes. Lectins are proteins or glycoproteins of nonimmune
origin that agglutinate cells and/or precipitate complex carbohydrates. Several lectins
behave like blood group antibodies and can be used as specific gene markers. We characterise
blood groups of Thunnus alalunga worldwide populations under a population genetics point of
view using lectins. Fishes from several populations of Mediterranean Sea, Atlantic, Pacific and
Indian Oceans were captured and 5 mL blood was obtained from each fish. Each fish was
treated with 8 FITC-labelled lectins. The binding activity of the lectins was detected using a
fluorescence assay. Several statistical procedures of populations genetics were employed to
analyse genetic variability, geographic differentiation, and genetic distance showing that: i)
there is genetic variability within Thunnus alalunga populations, ii) we detect highly
significant heterogeneity among populations, and considerable geographic differentiation, iii)
Mediterranean population is quite distant of North Atlantic population, iv) North and South
Atlantic populations are extremely distant, v) Pacific population is the most distant from the
others , vi) Gulf of Guinea and South Atlantic populations are distant, vii) Gulf of Guinea and
North Atlantic are proximate, viii) Indian and South Atlantic populations are also proximate.De nouveaux moyens fournis par la biologie cellulaire et moléculaire peuvent servir à
appliquer les connaissances sur la biologie et la pêche du poisson. A cet égard, nous
suggérons que l'utilisation des lectines peut constituer un processus raisonnable pour étudier
la structure des stocks de poisson. Les lectines sont des protéines ou des glycoprotéines
d'origine non-immunitaire qui agglutinent les cellules et/ou précipitent les carbohydrates
complexes. Plusieurs lectines se comportent comme des anticorps de groupes sanguins et
peuvent servir de marqueurs génétiques spécifiques. Nous identifions les groupes sanguins des
populations globales de Thunnus alalunga du point de vue de la génétique des populations au
moyen de lectines. Des poissons de plusieurs stocks de la Méditerranée, de l'Atlantique, du
Pacifique et de l'océan Indien ont été capturés, et 5 ml de leur sang a été prélevé. Chacun de ces poissons a été traité avec des lectines dénommées 8 FITC. L'activité agglutinante des
lectines a été détectée au moyen de tests de fluorescence. Plusieurs processus statistiques de
génétique des populations ont été employées pour analyser la variabilité générique, la
différentiation géographique et l'écartement génétique, d'où: i) il existe une variabilité
génétique su sein des populations de Thunnus alalunga, ii) nous détectons un degré très
significatif d'hétérogénéité entre les populations, et une différentiation géographique
considérable, iii) la population méditerranéenne se démarque assez de la population nordatlantique,
iv) les populations du nord et du sud de l'Atlantique sont extrêmement distinctes, v)
la population du Pacifique est celle qui se différencie le plus des autres, vi) les populations du golfe de Guinée et de l'Atlantique sud sont distinctes, vii) les populations du golfe de Guinée et
de l'Atlantique nord sont proches, viii) les populations de l'océan Indien et de l'Atlantique sud
sont également proches.Las nuevas herramientas de biología molecular y celular se pueden utilizar para implementar el
conocimiento de la biología de los peces y de la pesca. En este sentido, proponemos la utilización
de lectinas como procedimiento comprensible para estudiar la estructura de población de los
peces. Las lectinas son proteínas o glucoproteínas de origen no inmune que aglutinan células o
precipitan carbohidratos complejos. Muchas lectinas se comportan como anticuerpos de grupos
sanguíneos y pueden utilizarse como marcadores genéticos específicos. Hemos identificado grupos
sanguíneos de poblaciones de Thunnus alalunga de todo el mundo desde el punto de vista de
genética de poblaciones mediante lectinas. Se capturaron peces de varias poblaciones del mar
Mediterráneo y de los océanos Atlántico, Pacífico e Índico y se les extrajo 5 mL de sangre a cada
uno. Se trató a cada pez con lectinas marcadas con FITC 8. La actividad aglutinante de la lectina
se detectó utilizando fluorimetrías. Se emplearon varios procedimientos estadísticos de genética
de poblaciones para analizar la variabilidad genética, diferenciación geográfica y distancia
genética, que mostraron que: i) existe una variabilidad genética dentro de las poblaciones de
Thunnus alalunga; ii) detectamos una heterogeneidad muy significativa entre las poblaciones y
una considerable diferenciación geográfica; iii) la población mediterránea se distancia bastante
de la población del Atlántico Norte, iv) las poblaciones del Atlántico norte y sur son
extremadamente distantes; v) La población del Pacífico es la que presenta una mayor distancia
con respecto a las demás; vi) las poblaciones del Atlántico Sur y del Golfo de Guinea son
distantes; vii) las poblaciones del Golfo de Guinea y el Atlántico norte son próximas; viii) las poblaciones del Índico y el Atlántico sur también son próximas
2PI effective action and gauge invariance problems
The problem of maintaining gauge invariance when truncating the two particle
irreducible (2PI) effective action has been studied recently by several
authors. Here we give a simple and very general derivation of the gauge
dependence identities for the off-shell 2PI effective action. We consider the
case where the gauge is fixed by an arbitrary function of the quantum gauge
field, subject only to the restriction that the Faddeev-Popov matrix is
invertable. We also study the background field gauge. We address the role that
these identies play in solving gauge invariance problems associated with
physical quantities calculated using a truncated on-shell 2PI effective action.Comment: 11 pages, version accepted for publication in Eur. Phys. Jour.
Detecting the presence-absence of bluefin tuna by automated analysis of medium-range sonars on fishing vessels
This study presents a methodology for the automated analysis of commercial medium-range sonar signals for detecting presence/absence of bluefin tuna (Tunnus thynnus) in the Bay of Biscay. The approach uses image processing techniques to analyze sonar screenshots. For each sonar image we extracted measurable regions and analyzed their characteristics. Scientific data was used to classify each region into a class (“tuna” or “no-tuna”) and build a dataset to train and evaluate classification models by using supervised learning. The methodology performed well when validated with commercial sonar screenshots, and has the potential to automatically analyze high volumes of data at a low cost. This represents a first milestone towards the development of acoustic, fishery-independent indices of abundance for bluefin tuna in the Bay of Biscay. Future research lines and additional alternatives to inform stock assessments are also discussed
Study on the migrations and stock structure of Albacore (Thunnus alalunga) from the Atlantic Ocean and the Mediterranean sea based on conventional tag release-recapture experiences
In this paper a study on the migrations of albacore from the North Atlantic Ocean and the
Mediterranean Sea is made, based on the information from conventional tag release-recapture
experiences. Information on 643 recaptured fish from a total of 23,777 tagged fish has been
analyzed. This information highlights the long distance movements of albacore, their
transoceanic migrations and the possibility of an interchange of fish between the North
Atlantic and the Mediterranean.Le présent document fait état d'une étude sur les migrations du germon de l'Atlantique nord et
de la Méditerranée, d'après des informations provenant d'expériences de marquage et de
recapture avec marques conventionnelles. L'information correspondant à 643 poissons
recapturés sur un total de 23.777 poissons marqués a été analysée. Cette information révèle les
déplacements du germon sur de grandes distances, ses migrations transocéaniques et
l'éventualité d'échanges de poissons entre l'Atlantique nord et la Méditerranée.En este documento se hace un estudio de las migraciones del atún blanco del Atlántico norte y
Mediterráneo en base a las informaciones procedentes de las experiencias de marcado-recaptura
convencionales. Se ha analizado la información procedente de 643 peces
recapturados de un total de 23.777 peces marcados. Con esta información se ponen de
manifiesto los grandes movimientos del atún blanco, sus desplazamientos transoceánicos y la
posibilidad de intercambio de peces entre el Atlántico norte y el Mediterráneo
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