Showing papers by "University of Valencia published in 2001"

Astrocytes Give Rise to New Neurons in the Adult Mammalian Hippocampus

Abstract: Neurogenesis in the dentate gyrus of the hippocampus persists throughout life in many vertebrates, including humans. The progenitors of these new neurons reside in the subgranular layer (SGL) of the dentate gyrus. Although stem cells that can self-renew and generate new neurons and glia have been cultured from the adult mammalian hippocampus, the in vivo primary precursors for the formation of new neurons have not been identified. Here we show that SGL cells, which express glial fibrillary acidic protein and have the characteristics of astrocytes, divide and generate new neurons under normal conditions or after the chemical removal of actively dividing cells. We also describe a population of small electron-dense SGL cells, which we call type D cells and are derived from the astrocytes and probably function as a transient precursor in the formation of new neurons. These results reveal the origins of new neurons in the adult hippocampus.

MAGPACK1 A package to calculate the energy levels, bulk magnetic properties, and inelastic neutron scattering spectra of high nuclearity spin clusters

Abstract: M agnetic molecular clusters, i.e., molecular assemblies formed by a finite number of exchange-coupled magnetic moments, are currently receiving much attention in several active areas of research as molecular chemistry, magnetism, and biochemistry. A reason for this interest lies in the possibility to use simple molecular clusters as magnets of nanometer size exhibiting unusual magnetic properties as superparamagnetic like behavior or quantum tunneling of magnetization.2 – 4 Organic molecules of increasing sizes and large number of unpaired electrons are being explored as a means of obtaining building blocks for molecule-based magnets.5 Magnetic clusters of metal ions are also relevant in biochemistry.6 This area between molecule and bulk will require new theoretical concepts and techniques for investigation of their peculiar properties. Still, the theoretical treatment required to understand the magnetic and spectroscopic properties of this wide variety of compounds is a challenging problem in molecular magnetism.7 For a long time, this problem has been mostly restricted to treat comparatively simple clusters comprising a reduced number of exchange-coupled centers and special spin topologies, for which solutions can be obtained either analytically or numerically. However, on increasing the spin nuclearity of the cluster, the problem rapidly becomes unapproachable because the lack of translational symmetry in the clusters. An additional complication is the spin anisotropy of the cluster. Until now only the isotropic-exchange case has been treated, so as to take full advantage of the spin symmetry of the cluster.8 In this article we present a very powerful and efficient computational approach to solve the exchange problem in high nuclearity spin clusters with all kind of exchange interactions (isotropic and anisotropic), including the single-ion anisotropic effects. The clusters are formed by an arbitrary number of exchangecoupled centers that combine different spin values and arbitrary topology. This approach is based on the use of the irreducible tensor operators (ITO) technique.7, 9 – 12 It allows evaluation of both eigenvalues and eigenvectors of the system, and then, calculation of the magnetic susceptibility, magnetization, or heat capacity, and also the inelastic neutron scattering spectra. In the following sections we will present both the theory and the four different implemented FORTRAN programs that integrate a package called MAGPACK . In the last section some examples are presented in order to show the possibilities of the programs.

Methyl-CpG-binding proteins. Targeting specific gene repression.

Abstract: CpG methylation, the most common epigenetic modification of vertebrate genomes, is primarily associated with transcriptional repression. MeCP2, MBD1, MBD2, MBD3 and MBD4 constitute a family of vertebrate proteins that share the methyl-CpG-binding domain (MBD). The MBD, consisting of about 70 residues, possesses a unique alpha/beta-sandwich structure with characteristic loops, and is able to bind single methylated CpG pairs as a monomer. All MBDs except MBD4, an endonuclease that forms a complex with the DNA mismatch-repair protein MLH1, form complexes with histone deacetylase. It has been established that MeCP2, MBD1 and MBD2 are involved in histone deacetylase-dependent repression and it is likely that this is also the case for MBD3. The current model proposes that MBD proteins are involved in recruiting histone deacetylases to methyl CpG-enriched regions in the genome to repress transcription. The lack of selectivity for MBD association with particular DNA sequences indicates that other mechanisms account for their recruitment to particular regions in the genome.

Doublecortin expression in the adult rat telencephalon.

Abstract: Doublecortin (DCX) is a protein required for normal neuronal migration in the developing cerebral cortex, where it is widely expressed in both radially and tangentially migrating neuroblasts. Moreover, it has been observed in the adult rostral migratory stream, which contains the neuronal precursors traveling to the olfactory bulb. We have performed DCX immunocytochemistry in the adult rat brain to identify precisely the neuronal populations expressing this protein. Our observations confirm the presence of DCX immunoreactive cells with the characteristic morphology of migrating neuroblasts in the subventricular zone, rostral migratory stream and the main and accessory olfactory bulbs. We have also found putative migratory cells expressing DCX in regions were no adult neuronal migration has been described, as the corpus callosum, the piriform cortex layer III/endopiriform nucleus and the striatum. Surprisingly, many cells with the phenotype of differentiated neurons were DCX immunoreactive; e.g. certain granule neurons in the hilar border of the granular layer of the dentate gyrus, some neuronal types in the piriform cortex layer II, granule and periglomerular neurons in the main and accessory olfactory bulbs, and isolated cells in the striatum. Almost all DCX immunoreactive cells also express the polysialylated form of neural cell adhesion molecule and have a similar distribution to rat collapsin receptor-mediated protein-4, two molecules involved in neuronal structural plasticity. Given these results, we hypothesize that DCX expression in differentiated neurons could be related to its capacity for microtubule reorganization and that this fact could be linked to axonal outgrowth or synaptogenesis.

Resuscitation With Room Air Instead of 100% Oxygen Prevents Oxidative Stress in Moderately Asphyxiated Term Neonates

Abstract: Background. Traditionally, asphyxiated newborn infants have been ventilated using 100% oxy- gen. However, a recent multinational trial has shown that the use of room air was just as efficient as pure oxygen in securing the survival of severely asphyxiated newborn infants. Oxidative stress markers in moderately asphyx- iated term newborn infants resuscitated with either 100% oxygen or room air have been studied for the first time in this work. Methods. Eligible term neonates with perinatal as- phyxia were randomly resuscitated with either room air or 100% oxygen. The clinical parameters recorded were those of the Apgar score at 1, 5, and 10 minutes, the time of onset of the first cry, and the time of onset of the sustained pattern of respiration. In addition, reduced and oxidized glutathione concentrations and antioxidant en- zyme activities (superoxide dismutase, catalase, and glu- tathione peroxidase) were determined in blood from the umbilical artery during delivery and in peripheral blood at 72 hours and at 4 weeks' postnatal age. Results. Our results show that the room-air resusci- tated (RAR) group needed significantly less time to first cry than the group resuscitated with 100% oxygen (1.2 6 0.6 minutes vs 1.7 6 0.5). Moreover, the RAR group needed less time undergoing ventilation to achieve a sustained respiratory pattern than the group resuscitated with pure oxygen (4.6 6 0.7 vs 7.5 6 1.8 minutes). The reduced-to-oxidized-glutathione ratio, which is an accu- rate index of oxidative stress, of the RAR group (53 6 9) at 28 days of postnatal life showed no differences with the control nonasphyxiated group (50 6 12). However, the reduced-to-oxidized-glutathione ratio of the 100% ox- ygen-resuscitated group (OxR) (15 6 5) was significantly lower and revealed protracted oxidative stress. Further- more, the activities of superoxide dismutase and catalase in erythrocytes were 69% and 78% higher, respectively, in the OxR group than in the control group at 28 days of postnatal life. Thus, this shows that these antioxidant enzymes, although higher than in controls, could not cope with the ongoing generation of free radicals in the OxR group. However, there were no differences in anti- oxidant enzyme activities between the RAR group and the control group at this stage. Conclusions. There are no apparent clinical disadvan- tages in using room air for ventilation of asphyxiated neonates rather than 100% oxygen. Furthermore, RAR infants recover more quickly as assessed by Apgar scores, time to the first cry, and the sustained pattern of respi- ration. In addition, neonates resuscitated with 100% ox- ygen exhibit biochemical findings reflecting prolonged oxidative stress present even after 4 weeks of postnatal life, which do not appear in the RAR group. Thus, the current accepted recommendations for using 100% oxy- gen in the resuscitation of asphyxiated newborn infants should be further discussed and investigated. Pediatrics 2001;107:642- 647; asphyxia, newborn infant, resuscitation, glutathione, oxidative stress.

Influence of soil properties on the aggregation of some Mediterranean soils and the use of aggregate size and stability as land degradation indicators

Abstract: Soil aggregation in relation to other soil properties was studied along a climatological transect in the Southeast of Spain. Three sites were selected along this transect ranging from semiarid to subhumid climatological conditions. The aggregate size distribution, the macro and microaggregate stability of the superficial soil horizon and their relations with other soil properties were analysed. Large aggregates (>10, 10–5, 5–2 mm) were present in highest proportions in the most arid of the studied areas. These large aggregates were associated with high values of water-stable microaggregates; however, they did not improve soil structure and are related to high bulk densities and low water retention. Aggregates 1–0.105 mm were positively correlated to medium, fine, very fine sand and silt fractions and to organic matter. Aggregates Water stability of microaggregates showed a positive correlation with clay content while the stability of the macroaggregates depended on the organic matter content when the organic matter content was greater than 5 or 6%. Below that threshold the carbonate content was strongly correlated with aggregate stability. A general conceptual scheme of associations between aggregate size distribution, water-stable microaggregation and textural characteristics for the area was developed. The land use history affecting soil overlaps the pattern of climatological situations and has to be taken into account. Aggregate size distribution and stability can be used as indicator of soil degradation, but not as a unique parameter.

Designing the properties of dispersion-flattened photonic crystal fibers

Abstract: We present a systematic study of group-velocity-dispersion properties in photonic crystal fibers (PCF’s). This analysis includes a thorough description of the dependence of the fiber geometrical dispersion on the structural parameters of a PCF. The interplay between material dispersion and geometrical dispersion allows us to established a well-defined procedure to design specific predetermined dispersion profiles. We focus on flattened, or even ultraflattened, dispersion behaviors both in the telecommunication window (around 1.55 µm) and in the Ti-Za laser wavelength range (around 0.8 µm). We show the different possibilities of obtaining normal, anomalous, and zero dispersion curves in the above frequency domains and discuss the limits for the existence of the above dispersion profiles.

Para uma imagem não deformada do trabalho científico

Abstract: O presente artigo pretende evidenciar a importância de (re)conhecer as visoes deformadas dos professores sobre o trabalho cientifico, para a partir dai poderem consciencializar e modificar as suas proprias concepcoes epistemologicas acerca da natureza da ciencia e da construcao do conhecimento cientifico. Afirma-se que o trabalho colaborativo de grupos de docentes, quando da realizacao de workshops, e bem mais produtivo e positivo do que o trabalho individual na deteccao de tais visoes. Enumeram-se sete visoes deformadas; alias, abundantemente referidas na literatura, aqui intencionalmente extensa. Caracterizam-se tais visoes deformadas e desenvolvem-se sobre elas consideracoes que ajudam a reflexao. Por outro lado, referem-se as caracteristicas do trabalho cientifico e tecem-se orientacoes epistemologicamente mais adequadas, por sua vez capazes de ajudar a (re)pensar e a qualificar o trabalho cientifico. Sugerem-se implicacoes para o ensino das ciencias e, num contexto mais vasto, para a Nova Didatica das Ciencias.

On the Asymmetric Recognition of Good and Bad News in France, Germany and the United Kingdom

Abstract: We investigate whether accounting systems recognise bad news more promptly in earnings than good news, where news is proxied by changes in share price. The analysis is based on a sample of firm/years drawn from France, Germany, and the UK during 1990 to 1998. These three countries are the originators of three distinct legal traditions. Previous studies have argued that asymmetric recognition, one manifestation of conservative accounting, is sensitive to legal background and history. We find that in all three countries the contemporaneous association between earnings and returns is much stronger for bad news (i.e. when price changes are negative) than for good news, and although the results are strongest for the UK, and then France, the inter-country differences are not statistically significant. The stronger reaction to bad news is more pronounced for firms with relatively low capitalisation. We also find that the relative persistence of profits and losses are consistent with asymmetric recognition in France and the UK, but not in Germany, and that the more timely recognition of bad news is maintained even when we control for earnings persistence. When we extend the model to include price changes from previous periods, we see that the stronger reaction to bad news decays over time. The results from this model also suggest that 'pervasive' conservatism, unrelated to news, is observed in Germany and France, but the UK results are consistent with optimism. Although asymmetric recognition is generally strongest in the UK and weakest in Germany, and this broadly conforms to our expectations, the differences are less clear than the results from earlier periods

Human Endometrial Mucin MUC1 Is Up-Regulated by Progesterone and Down-Regulated In Vitro by the Human Blastocyst

Abstract: Expression of MUC1 in endometrial epithelium has been suggested to create a barrier to embryo attachment that must be lifted at the time of implantation. In this study, we investigated the hormonal regulation of human endometrial MUC1 in hormone replacement therapy cycles and in the human blastocyst. We also analyzed the embryonic regulation of MUC1 in human endometrial epithelial cells (EECs) during the apposition and adhesion phases of human implantation using two different in vitro models. Our results indicate that endometrial MUC1 mRNA and immunoreactive protein increase in receptive endometrium compared to nonreceptive endometrium. Human blastocysts express MUC1, as demonstrated by reverse transcription-polymerase chain reaction and immunocytochemistry, localized at the trophectoderm. In vitro, MUC1 was present at the surface of primary cultures of human EEC, and presence of a human blastocyst (i.e., apposition phase) increases EEC MUC1 protein and mRNA compared to control EEC lacking embryos. Interestingly, when human blastocysts were allowed to attach to the EEC monolayer (i.e., adhesion phase), MUC1 was locally removed in a paracrine fashion on EEC at the implantation site. These results demonstrate a coordinated hormonal and embryonic regulation of EEC MUC1. Progesterone combined with estradiol priming induces an up-regulation of MUC1 at the receptive endometrium. During the apposition phase, presence of a human embryo increases EEC MUC1. However, at the adhesion phase, the embryo induces a paracrine cleavage of EEC MUC1 at the implantation site. These findings strongly suggest that MUC1 may act as an endometrial antiadhesive molecule that must be locally removed by the human blastocyst during the adhesion phase.

Daily Air Temperature and Electricity Load in Spain

Abstract: Weather has a significant impact on different sectors of the economy. One of the most sensitive is the electricity market, because power demand is linked to several weather variables, mainly the air temperature. This work analyzes the relationship between electricity load and daily air temperature in Spain, using a population-weighted temperature index. The electricity demand shows a significant trend due to socioeconomic factors, in addition to daily and monthly seasonal effects that have been taken into account to isolate the weather influence on electricity load. The results indicate that the relationship is nonlinear, showing a “comfort interval” of ±3°C around 18°C and two saturation points beyond which the electricity load no longer increases. The analysis has also revealed that the sensitivity of electricity load to daily air temperature has increased along time, in a higher degree for summer than for winter, although the sensitivity in the cold season is always more significant than in th...

Spatial shaping of cochlear innervation by temporally regulated neurotrophin expression.

Abstract: Previous work suggested qualitatively different effects of neurotrophin 3 (NT-3) in cochlear innervation patterning in different null mutants We now show that all NT-3 null mutants have a similar phenotype and lose all neurons in the basal turn of the cochlea To understand these longitudinal deficits in neurotrophin mutants, we have compared the development of the deficit in the NT-3 mutant to the spatial-temporal expression patterns of brain-derived neurotrophic factor (BDNF) and NT-3, using lacZ reporters in each gene and with expression of the specific neurotrophin receptors, trkB and trkC In the NT-3 mutant, almost normal numbers of spiral ganglion neurons form, but fiber outgrowth to the basal turn is eliminated by embryonic day (E) 135 Most neurons are lost between E135 and E155 During the period preceding apoptosis, NT-3 is expressed in supporting cells, whereas BDNF is expressed mainly in hair cells, which become postmitotic in an apical to basal temporal gradient During the period of neuronal loss, BDNF is absent from the basal cochlea, accounting for the complete loss of basal turn neurons in the NT-3 mutant The spatial gradients of neuronal loss in these two mutants appear attributable to spatial-temporal gradients of neurotrophin expression Our immunocytochemical data show equal expression of their receptors, TrkB and TrkC, in spiral sensory neurons and thus do not relate to the basal turn loss Mice in which NT-3 was replaced by BDNF show a qualitative normal pattern of innervation at E135 This suggests that the pattern of expression of neurotrophins rather than their receptors is essential for the spatial loss of spiral sensory neurons in NT-3 null mutants

Cuantificación de insulinorresistencia con los valores de insulina basal e índice HOMA en una población no diabética

Abstract: Fundamento Calcular la prevalencia y definir el sindrome de insulinorresistencia mediante la determinacion de insulinemia basal y el indice HOMA, y estudiar su relacion con otros componentes del sindrome metabolico. Sujetos y metodo Estudiamos una poblacion de 292 sujetos no diabeticos, de ambos sexos y edades entre 20 y 65 anos, seleccionados por un metodo de muestreo simple aleatorio entre los que consultaron durante un ano en un centro de salud (en el area metropolitana de Valencia), mediante un metodo de busqueda oportunista. De ellos se selecciono a un subgrupo formado por 96 sujetos que no tenian caracteristicas clinicas ni analiticas del sindrome de insulinorresistencia, y se estudiaron los lipidos plasmaticos, parametros antropometricos, glucosa e insulina plasmatica y el valor del indice HOMA. Resultados El diagnostico de insulinorresistencia se ha establecido por los cortes del percentil 90 de la subpoblacion sin parametros clinicos ni analiticos del sindrome de insulinorresistencia, considerando una insulina plasmatica basal de 16,7 mU/l o superior, o indice HOMA de 3,8 o mayor. El indice HOMA es mas sensible que la insulina plasmatica para el diagnostico de insulinorresistencia. La prevalencia de insulinorresistencia (HOMA ≥ 3,8) en la poblacion estudiada por nosotros es elevada, 31,8%, siendo mas frecuente en hombres que en mujeres. Conclusion Ademas de los valores plasmaticos de insulina e indice HOMA, los mejores indicadores clinicobioquimicos de insulinorresistencia son los valores de glucemia en ayunas, el indice de masa corporal (IMC) y los trigliceridos plasmaticos. Asi, la razon de probabilidad de tener insulinorresistencia es de 5,9, 2,6 y 2,2, respectivamente para glucemia ≥ 110 mg/dl, IMC ≥ 25 kg/m2 y trigliceridos ≥ 150 mg/dl.

Molecule-based magnets formed by bimetallic three-dimensional oxalate networks and chiral tris(bipyridyl) complex cations. The series [ZII(bpy)3][ClO4][MIICrIII(ox)3] (ZII = Ru, Fe, Co, and Ni; MII = Mn, Fe, Co, Ni, Cu, and Zn; ox = oxalate dianion).

Abstract: The synthesis, structure, and physical properties of the series of molecular magnets formulated as [ZII(bpy)3][ClO4][MIICrIII(ox)3] (ZII = Ru, Fe, Co, and Ni; MII = Mn, Fe, Co, Ni, Cu, and Zn; ox = oxalate dianion) are presented. All the compounds are isostructural to the [Ru(bpy)3][ClO4][MnCr(ox)3] member whose structure (cubic space group P4(1)32 with a = 15.506(2) A, Z = 4) consists of a three-dimensional bimetallic network formed by alternating MII and CrIII ions connected by oxalate anions. The identical chirality (lambda in the solved crystal) of all the metallic centers determines the 3D chiral structure adopted by these compounds. The anionic 3D sublattice leaves some holes where the chiral [Z(bpy)3]2+ and ClO4- counterions are located. These compounds behave as soft ferromagnets with ordering temperatures up to 6.6 K and coercive fields up to 8 mT.

The medial sural artery perforator free flap.

Abstract: The medial sural artery supplies the medial gastrocnemius muscle and sends perforating branches to the skin. The possible use of these musculocutaneous perforators as the source of a perforator-based free flap was investigated in cadavers. Ten legs were dissected, and the topography of significant perforating musculocutaneous vessels on both the medial and the lateral gastrocnemius muscles was recorded. A mean of 2.2 perforators (range, 1 to 4) was noted over the medial gastrocnemius muscle, whereas in only 20 percent of the specimens was a perforator of moderate size noted over the lateral gastrocnemius muscle. The perforating vessels from the medial sural artery clustered about 9 to 18 cm from the popliteal crease. When two perforators were present (the most frequent case), the perforators were located at a mean of 11.8 cm (range, 8.5 to 15 cm) and 17 cm (range, 15 to 19 cm) from the popliteal crease. A series of six successful clinical cases is reported, including five free flaps and one pedicled flap for ipsilateral lower-leg and foot reconstruction. The dissection is somewhat tedious, but the vascular pedicle can be considerably long and of suitable caliber. Donor-site morbidity was minimal because the muscle was not included in the flap. Although the present series is short, it seems that the medial sural artery perforator flap can be a useful flap for free and pedicled transfer in lower-limb reconstruction.

NMDA receptor antagonist treatment induces a long‐lasting increase in the number of proliferating cells, PSA‐NCAM‐immunoreactive granule neurons and radial glia in the adult rat dentate gyrus

Abstract: During adulthood, neural precursors located in the subgranular zone of the dentate gyrus continue to proliferate, leading to the generation of new granule neurons. These recently generated cells transiently express the polysialylated form of the neural cell adhesion molecule, PSA-NCAM, and are supported by radial glia-like cells that are likely to play a role in neuronal migration and differentiation, or even act as their precursors. Previous reports indicate that treatment with NMDA receptor antagonists stimulates adult neurogenesis in the dentate gyrus, and because of the potential therapeutic value of this approach, we were interested in further characterizing the consequences of pharmacologically modulating this process. We treated adult rats with the competitive NMDA receptor antagonist, CGP43487, and examined cell proliferation, PSA-NCAM expression, and changes in the radial glia cell population in the subgranular zone at different time points. In addition, we sought to determine if this treatment led to changes in cell death or gliotic reactions. The number of proliferating cells in the subgranular region of the dentate gyrus was increased significantly 2 days after treatment and it remained elevated 7 days postinjection. PSA-NCAM-immunoreactive granule cells and nestin-expressing radial glia-like cells also increased in number 7 days after the treatment. In contrast, we did not observe any change in granule cell death, and we were unable to detect any microglial or astroglial reaction during the first 7 days after treatment. Thus, NMDA receptor antagonist treatment serves as a valuable tool to increase neurogenesis in the adult hippocampus without undesirable collateral deleterious effects.

Fasciola hepatica and lymnaeid snails occurring at very high altitude in South America.

Abstract: Fascioliasis due to the digenean species Fasciola hepatica has recently proved to be an important public health problem, with human cases reported in countries of the five continents, including severe symptoms and pathology, with singular epidemiological characteristics, and presenting human endemic areas ranging from hypo- to hyperendemic. One of the singular epidemiological characteristics of human fascioliasis is the link of the hyperendemic areas to very high altitude regions, at least in South America. The Northern Bolivian Altiplano, located at very high altitude (3800-4100 m), presents the highest prevalences and intensities of human fascioliasis known. Sequences of the internal transcribed spacers ITS-1 and ITS-2 of the nuclear ribosomal DNA of Altiplanic Fasciola hepatica and the intermediate snail host Lymnaea truncatula suggest that both were recently introduced from Europe. Studies were undertaken to understand how the liver fluke and its lymnaeid snail host adapted to the extreme environmental conditions of the high altitude and succeeded in giving rise to high infection rates. In experimental infections of Altiplanic lymnaeids carried out with liver fluke isolates from Altiplanic sheep and cattle, the following aspects were studied: miracidium development inside the egg, infectivity of miracidia, prepatent period, shedding period, chronobiology of cercarial emergence, number of cercariae shed by individual snails, survival of molluscs at the beginning of the shedding process, survival of infected snails after the end of the shedding period and longevity of shedding and non-shedding snails. When comparing the development characteristics of European F. hepatica and L. truncatula, a longer cercarial shedding period and a higher cercarial production were observed, both aspects related to a greater survival capacity of the infected lymnaeid snails from the Altiplano. These differences would appear to favour transmission and may be interpreted as strategies associated with adaptation to high altitude conditions.

Antecedents and consequences of market orientation in public organisations

Abstract: The aim of this article is to link research on market orientation in the field of marketing with the proposals of reform and modernisation made in the administrative and political field. Market orientation in business organisations is a highly topical issue, or even more, it is considered by someacademicians as the new marketing paradigm. Following these studies and their proposals of application in other sectors, a market orientation model is developed, from a public management perspective, in the setting of local governments through testing a set ofhypotheses about the construct and its antecedents and consequences. Antecedents explaining why some local governments are more market oriented than others are identified. Moreover, market orientation is shown to influence public organisation performance.

Diet of the bottlenose dolphin ( Tursiops truncatus ) in the western Mediterranean Sea

Abstract: The stomach contents of 16 bottlenose dolphins Tursiops truncatus (Cetacea: Odontoceti) stranded in the Spanish Mediterranean coast were examined. Remains and size of prey were analysed and correlated with the ecological characteristics and behavioural patterns of this dolphin. Fish and cephalopods represented the main diet components, and hake Merluccius merluccius was the most important prey. The food habits were considered as mainly demersal according to the characteristics of the prey. The study suggested ontogenic and sexual differences in feeding behaviour based on diet composition and hake size. The potential causative factors, particularly as they relate to dolphin social structure, are discussed.