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From the classical gold standard up to the current ERM2 arrangement of the European Union, target zones have been a widely used exchange regime in contemporary history. This paper presents a benchmark model that rationalizes the choice of... more
From the classical gold standard up to the current ERM2 arrangement of the European Union, target zones have been a widely used exchange regime in contemporary history. This paper presents a benchmark model that rationalizes the choice of target zones over the rest of regimes: the fixed rate, the free float and the managed float. It is shown that the
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This paper studies the contribution of Information and Communication Technologies (ICT) to economic growth and labor productivity growth in Andalucía (Spain) over 1995-2004. We find that the contribution of ICT assets to total market GVA... more
This paper studies the contribution of Information and Communication Technologies (ICT) to economic growth and labor productivity growth in Andalucía (Spain) over 1995-2004. We find that the contribution of ICT assets to total market GVA growth is quantitatively modest. However the contribution to GVA growth and employment growth within the intensive ICT sectors has experienced a considerable increase during the
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This paper analyzes the linkages between the credibility of a target zone regime, the volatility of the exchange rate, and the width of the band where the exchange rate is allowed to fluctuate. These three concepts should be related since... more
This paper analyzes the linkages between the credibility of a target zone regime, the volatility of the exchange rate, and the width of the band where the exchange rate is allowed to fluctuate. These three concepts should be related since the band width induces a trade-off between credibility and volatility. Narrower bands give less scope for the exchange rate to
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This paper analyzes the linkages between the credibility of a target zone regime, the volatility of the exchange rate, and the width of the band where the exchange rate is allowed to fluctuate. These three concepts should be related since... more
This paper analyzes the linkages between the credibility of a target zone regime, the volatility of the exchange rate, and the width of the band where the exchange rate is allowed to fluctuate. These three concepts should be related since the band width induces a trade-off between credibility and volatility. Narrower bands should give less scope for the exchange rate
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The spatiotemporal sequence of the appearance of cholinergic structures in the brain of Xenopus laevis during development was studied by means of choline acetyltransferase (ChAT) immunohistochemistry. The first ChAT labeling in the... more
The spatiotemporal sequence of the appearance of cholinergic structures in the brain of Xenopus laevis during development was studied by means of choline acetyltransferase (ChAT) immunohistochemistry. The first ChAT labeling in the central nervous system of Xenopus was obtained at late embryonic stages in the spinal motoneurons, the cranial nerve motor nuclei of the brainstem, and in amacrine cells of the retina. During premetamorphosis, these cholinergic structures maturated significantly and new ChAT-immunoreactive cells were observed in several other nuclei such as the solitary tract nucleus, isthmic nucleus, laterodorsal and pedunculopontine tegmental nuclei, epiphysis, dorsal habenular nucleus, medial amygdala, bed nucleus of the stria terminalis, and dorsal pallidum. Further maturation continued through prometamorphosis and the climax of the metamorphosis together with the appearance of new cell groups in the efferent octaval nucleus, ventral hypothalamic nucleus, anterior pre...
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Many of the genes involved in brain patterning during development are highly conserved in vertebrates and similarities in their expression patterns help to recognize homologous cell types or brain regions. Among these genes, Pax6 and Pax7... more
Many of the genes involved in brain patterning during development are highly conserved in vertebrates and similarities in their expression patterns help to recognize homologous cell types or brain regions. Among these genes, Pax6 and Pax7 are expressed in regionally restricted patterns in the brain and are essential for its development. In the present immunohistochemical study we analyzed the distribution of Pax6 and Pax7 cells in the brain of six representative species of tetrapods and lungfishes, the closest living relatives of tetrapods, at several developmental stages. The distribution patterns of these transcription factors were largely comparable across species. In all species only Pax6 was expressed in the telencephalon, including the olfactory bulbs, septum, striatum, and amygdaloid complex. In the diencephalon, Pax6 and Pax7 were distinct in the alar and basal parts, mainly in prosomeres 1 and 3. Pax7 specifically labeled cells in the optic tectum (superior colliculus) and ...
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Cladistians are primitive actinopterygian fishes mostly neglected in neuroanatomical studies. In the present study, the detailed neuroanatomical distribution of orexin (hypocretin)-like immunoreactive (OX-ir) cell bodies and fibers was... more
Cladistians are primitive actinopterygian fishes mostly neglected in neuroanatomical studies. In the present study, the detailed neuroanatomical distribution of orexin (hypocretin)-like immunoreactive (OX-ir) cell bodies and fibers was analyzed in the brain of two species representative of the two extant genera of cladistians. Antibodies against mammalian orexin-A and orexin-B peptides were used. Simultaneous detection of orexins with neuropeptide Y (NPY), tyrosine hydroxylase (TH), and serotonin (5-HT) was used to establish accurately the topography of the orexin system and to evaluate the possible interactions with NPY and monoaminergic systems. A largely common pattern of OX-ir distribution in the two cladistian species was observed. Most OX-ir cells were located in the suprachiasmatic nucleus and tuberal hypothalamus, whereas scarce cells were observed in the posterior tubercle. In addition, a population of OX-ir cells was found in the preoptic area only in Polypterus and some c...
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In this paper, we use a dynamic general equilibrium growth model to quantify the contribution of different technological sources to productivity growth in the three leading economies: Germany, Japan, and the U.S. The sources of technology... more
In this paper, we use a dynamic general equilibrium growth model to quantify the contribution of different technological sources to productivity growth in the three leading economies: Germany, Japan, and the U.S. The sources of technology are classified as representing either neutral progress or investment-specific progress. The latter can be split into two different types of equipment: information and communication technologies (ICT) and non-ICT equipment. We find that in the long run, neutral technological change is the main source of productivity growth in Germany. For Japan and the U.S., the main source of productivity growth is investment-specific technological change, mainly associated with ICT. We also find that a non negligible part of productivity growth has been due to technology specific to non-ICT equipment; this is mainly true after 1995.
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From the classical gold standard up to the current ERM2 arrangement of the European Union, target zones have been a widely used exchange regime in contemporary history. This paper presents a benchmark model that rationalizes the choice of... more
From the classical gold standard up to the current ERM2 arrangement of the European Union, target zones have been a widely used exchange regime in contemporary history. This paper presents a benchmark model that rationalizes the choice of target zones over the rest of regimes: the fixed rate, the free float and the managed float. It is shown that the monetary authority may gain efficiency by reducing volatility of both the exchange rate and the interest rate at the same time. Furthermore, the model is consistent with some known stylized facts in the empirical literature that previous models were not able to generate, namely, the positive relation between the exchange rate and the interest rate differential, the degree of non-linearity of the function linking the exchage rate to fundamentals and the shape of the exchange rate stochastic distribution. Keywords: Target zones, exchange rate agreements, monetary policy, time consistency. JEL classification: E52, F31, F33.
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Research Interests: Physiology, Nonparametric Statistics, Evolution, Immunohistochemistry, Treatment Outcome, and 43 moreDISTRIBUTION, IP, Brain, Neuropeptides, Humans, Practice, Cerebral Cortex, IS, Glioblastoma, Po, Female, Animals, Spinal Cord, Male, DB, Ms, Ac, Ri, Peptides, Sol, Amphibians, BST, Th, Tyrosine Hydroxylase, Clinical Sciences, Aged, Middle Aged, Adult, Neuropeptide Y, Analysis of Variance, STR, Locus coeruleus, LF, IT, Distribution, Cell Proliferation, Suprachiasmatic Nucleus, C, A, Preoptic Area, Brain Neoplasms, Ad, and Cc
Research Interests: Neuroscience, Psychology, Cognitive Science, Evolution, Immunohistochemistry, and 17 moreBrain Mapping, Xenopus, Animals, Spinal Cord, Acetylcholine, Amphibians, Biological evolution, Neurons, Ranidae, Reticular Formation, Neural pathways, Species Specificity, Suprachiasmatic Nucleus, Preoptic Area, Neurosciences, Choline Acetyltransferase, and Brain stem
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Research Interests: Zoology, Cognitive Science, Immunohistochemistry, Somatostatin, Hippocampus, and 17 moreBrain, Animals, Spinal Cord, Male, Central Nervous System, Peptides, The, Amphibians, Medical Physiology, Neurons, Larva, Macaca fascicularis, Species Specificity, Comparative Neurology, Neurosciences, Median Eminence, and Transient Expression
Polypterid bony fishes are believed to be basal to other living ray-finned fishes, and their brain organization is therefore critical in providing information as to primitive neural characters that existed in the earliest ray-finned... more
Polypterid bony fishes are believed to be basal to other living ray-finned fishes, and their brain organization is therefore critical in providing information as to primitive neural characters that existed in the earliest ray-finned fishes. The cholinergic system has been characterized in more advanced ray-finned fishes, but not in polypterids. In order to establish which cholinergic neural centers characterized the earliest ray-finned fishes, the distribution of choline acetyltransferase (ChAT) is described in Polypterus and compared with the distribution of this molecule in other ray-finned fishes. Cell groups immunoreactive for ChAT were observed in the hypothalamus, the habenula, the optic tectum, the isthmus, the cranial motor nuclei, and the spinal motor column. Cholinergic fibers were observed in both the telencephalic pallium and the subpallium, in the thalamus and pretectum, in the optic tectum and torus semicircularis, in the mesencephalic tegmentum, in the cerebellar crest, in the solitary nucleus, and in the dorsal column nuclei. Comparison of the data within a segmental neuromeric context indicates that the cholinergic system in polypterid fishes is generally similar to that in other ray-finned fishes, but cholinergic-positive neurons in the pallium and subpallium, and in the thalamus and cerebellum, of teleosts appear to have evolved following the separation of polypterids and other ray-finned fishes.
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The organization of the basal forebrain cholinergic system (BFCS) in the frog was studied by means of choline acetyltransferase (ChAT) immunohistochemistry. The BFCS was observed as a conspicuous cholinergic cell population extending... more
The organization of the basal forebrain cholinergic system (BFCS) in the frog was studied by means of choline acetyltransferase (ChAT) immunohistochemistry. The BFCS was observed as a conspicuous cholinergic cell population extending through the diagonal band, medial septal nucleus, bed nucleus of the stria terminalis, and pallidal regions. Abundant fiber labeling was also found around the labeled cell bodies. The combination of retrograde tract tracing with dextran amines and ChAT immunohistochemistry revealed intraseptal and intra-BFCS cholinergic connections. In addition, an extratelencephalic cholinergic input from the laterodorsal tegemental nucleus was demonstrated. The possible influence of monoaminergic inputs on the BFCS neurons was examined by means of tyrosine hydroxylase and serotonin immunohistochemistry combined with ChAT immunolabeling. Our results showed that catecholaminergic fibers overlapped the BFCS, with the exception of the medial septal nucleus. Serotoninergic innervation was widespread, but less abundant in the caudal extent of the BFCS. Taken together, our results on the localization of the cholinergic neurons in the basal forebrain and their relationship with cholinergic, catecholaminergic, and serotoninergic afferents have shown numerous common features with amniotes. In particular, anurans and mammals (for which most data is available) share a strikingly comparable organization pattern of the BFCS.
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The development of nitric oxide synthase (NOS) expression in the brain of Xenopus laevis tadpoles was studied by means of immunohistochemistry using specific antibodies against NOS and enzyme histochemistry for nicotinamide adenine... more
The development of nitric oxide synthase (NOS) expression in the brain of Xenopus laevis tadpoles was studied by means of immunohistochemistry using specific antibodies against NOS and enzyme histochemistry for nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase. Both techniques yielded identical results and were equally suitable for demonstrating the nitrergic system in the brain. The only mismatches were observed in the olfactory nerve and glomeruli and in the terminal nerve; they were intensely labeled with the NADPH-diaphorase technique but failed to stain with NOS immunohistochemistry. As early as stage 33, nitrergic cells were observed in the caudal rhombencephalon within the developing inferior reticular nucleus. At later embryonic stages, different sets of reticular and tegmental neurons were labeled in the middle reticular nucleus and, more conspicuously, in the laterodorsal and pedunculopontine tegmental nuclei. As development proceeded, new nitrergic cell groups gradually appeared in the mesencephalon, diencephalon, and telencephalon. A general caudorostral temporal sequence was observed, both in the whole brain and within each main brain subdivision. The premetamorphic period was mainly characterized by the maturation of the cell populations developed in the embryonic period. During prometamorphosis, the nitrergic system reached an enormous development, and many new cell groups were observed for the first time, in particular in the telencephalon. By the climax of metamorphosis, the pattern of organization of nitrergic cells and fibers observed in the brain was similar to that present in the adult brain. Transient expression of NOS was not detected in any brain region. Our data suggest that nitric oxide plays an important role during brain development of Xenopus. Comparison with the developmental pattern of nitrergic systems in other vertebrates shows that amphibians possess more common features with amniotes than with anamniotes.
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Pax6 and Pax7 are transcription factors essential for the development of the CNS. In addition, increasing data, mainly obtained in amniotes, support that they are expressed in subsets of neurons in the adult, likely playing a role in... more
Pax6 and Pax7 are transcription factors essential for the development of the CNS. In addition, increasing data, mainly obtained in amniotes, support that they are expressed in subsets of neurons in the adult, likely playing a role in maintaining neuron type identity. In the present study we analyzed the detailed distribution of Pax6 and Pax7 cells in the adult CNS of Xenopus laevis. Immunohistochemistry with antibodies that are required for high-resolution analysis of Pax-expressing cells was conducted. A wide distribution of Pax6 and Pax7 cells throughout the CNS was detected, with distinct patterns that showed only slight overlapping. Only Pax6 was expressed in the telencephalon, including the olfactory bulbs, septum, striatum and amygdaloid complex. In the diencephalon, Pax6 and Pax7 were distinct in the alar and basal parts, respectively, of prosomere 3. Large numbers of Pax6 and Pax7 cells were distributed in the pretectal region (alar plate of prosomere 1) but only Pax6 cells extended into basal plate. Pax7 specifically labeled cells in the optic tectum, including the ventricular zone, and Pax6 cells were the only cells found in the tegmentum. Pax6 was found in most granule cells of the cerebellum and Pax7 expression was found only in the ventricular zone. In the rostral rhombomere 1, Pax7 labeling was detected in cells of the ventricular zone of the alar plate, but numerous migrated cells were located in the basal plate, including the griseum centrale and the interpeduncular nucleus. Pax6 cells also formed a column of scattered neurons in the reticular formation and were found in the octavolateral area. The rhombencephalic ventricular zone of the alar plate expressed Pax7. Dorsal Pax7 cells and ventral Pax6 cells were found along the spinal cord separated from the ventricle, which did not show immunoreactivity. Our results show that the expression of Pax6 and Pax7 is widely maintained in the adult brain of Xenopus, like in urodele amphibians and in contrast to the situation described in amniotes. Therefore, in amphibians these transcription factors seem to be needed to maintain specific entities of subpopulations of neurons in the adult CNS.
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Research Interests: Immunohistochemistry, Chemical, Comparative, Nucleus Accumbens, IP, and 60 moreDopamine, Brain Mapping, Phylogeny, Vitamin D receptor, IS, Lizards, RH, Animals, Spinal Cord, RF, Turtles, Ct, PT, DB, Ms, dopamine receptor D4, Ac, Ri, Pdi, Substantia nigra, Sol, BST, Neurons, Th, Tyrosine Hydroxylase, Fluorescent Antibody Technique, LM, Neuropeptide Y, SCR, Ranidae, STR, Columbidae, Xenopus laevis, Basal ganglia, Poa, Locus coeruleus, Reticular Formation, Olfactory Bulb, LF, Substance P, IT, Cholinergic Systems, Mes, Neural pathways, Species Specificity, Neuropil, SPV, Brain Chemistry, Suprachiasmatic Nucleus, Catecholamines, C, R, L, Environment, Preoptic Area, Neurosciences, Pigeon, Interneurons, Telencephalon, and Cc
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This paper explores the contribution of Information and Communication Technologies (ICT) on economic growth and labor productivity growth of Andaluc??a during 1995-2004. We find that the contribution of ICT assets to total market GVA... more
This paper explores the contribution of Information and Communication Technologies (ICT) on economic growth and labor productivity growth of Andaluc??a during 1995-2004. We find that the contribution of ICT assets to total market GVA growth is quantitatively modest. ...
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Cladistians (Polypteriformes) are currently considered basal to other living ray-finned fishes (actinopterygians), and their brain organization is therefore critical to providing information about the primitive neural characters that... more
Cladistians (Polypteriformes) are currently considered basal to other living ray-finned fishes (actinopterygians), and their brain organization is therefore critical to providing information about the primitive neural characters that existed in the earliest ray-finned fishes. The organization of the serotonergic system in the brain has been carefully analyzed in most vertebrate groups, and in the present study we provide the first detailed information on the distribution of serotonergic cell bodies and fibers in the central nervous system of representative species of the two extant genera of cladistians, i.e. Polypterus senegalus and Erpetoichthys calabaricus, by means of immunohistochemistry against serotonin (5-HT). Distinct groups of immunoreactive cells were detected in the preoptic area, the hypothalamic paraventricular organ, the pineal organ, the pretectal region, the long column of the raphe in the rhombencephalic midline, the spinal cord, and amacrine cells in the inner nuclear layer of the retina. Fiber labeling was widely distributed in all main brain subdivisions but was more abundant in distinct pallial and subpallial areas, the preoptic area, the thalamus, the optic tectum, the tori semicircularis and lateralis, the rhombencephalic reticular formation, the nucleus of the solitary tract, and the dorsal aspect of the spinal cord. Our analysis makes it possible to establish which serotonergic structures characterized the earliest ray-finned fishes, and a comparison of these results with those from other classes of vertebrates, including a segmental analysis to correlate cell populations, reveals that most characteristics, such as the presence of serotonergic cells in the preoptic area and the basal hypothalamus, are preserved in all anamniotes. However, this system seems to be reduced in amniotes, mainly mammals, although important features are shared, such as the presence of serotonergic cells in the pineal organ, the retina, and the raphe nuclei.
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The organization of nitrergic systems in the brains of anuran and urodele amphibians was recently studied and significant differences were noted between both amphibian orders. However, comparable data are not available for the third order... more
The organization of nitrergic systems in the brains of anuran and urodele amphibians was recently studied and significant differences were noted between both amphibian orders. However, comparable data are not available for the third order of amphibians, the gymnophionans (caecilians). In the present study we have investigated the distribution of neuronal elements that express nitric oxide synthase (NOS) in the brain of the gymnophionan amphibian Dermophis mexicanus by means of immunohistochemistry with specific antibodies against NOS and enzyme histochemistry for NADPH-diaphorase. Both techniques yielded identical results and were equally suitable to demonstrate the nitrergic system. In addition, they were useful tools in the identification of cell groups and brain structures, otherwise indistinct in the brains of caecilians. The distribution of nitrergic structures observed in Dermophis conforms to the overall amphibian pattern but numerous distinct peculiarities were also noted. These included a dense innervation of the olfactory bulbs but a lack of reactivity in olfactory and vomeronasal fibers and glomeruli. A large population of nitrergic cells in the striatum and the presence of thalamic neurons, as well as the specific distribution of nitrergic cells in the isthmic region, are some of the differential features in the gymnophionan brain. Given the variability among species in the same class of vertebrates any discussion including amphibians should also include evidence for gymnophionans.
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Lungfishes are currently considered the closest living relatives of tetrapods and represent an interesting group for the study of evolutionary traits in the transition from fishes to tetrapods. The brains of lungfishes have received... more
Lungfishes are currently considered the closest living relatives of tetrapods and represent an interesting group for the study of evolutionary traits in the transition from fishes to tetrapods. The brains of lungfishes have received little attention in comparative studies probably due to the difficulty of obtaining these unique animals. In the present study the distribution of orexin (hypocretin)-like immunoreactivity was studied in the brain of the African lungfish Protopterus dolloi and the Australian lungfish Neoceratodus forsteri by using antibodies directed against the mammalian orexin-A and orexin-B peptides. Simultaneous detection of orexins and tyrosine hydroxylase or serotonin was used to assess the precise location of the orexins in the brain and to evaluate the possible influence of the orexin system on the monoaminergic cell groups. Although some differences were noted, a common pattern for the distribution of orexins in the two lungfishes studied was observed. In both species, most immunoreactive neurons were observed in the suprachiasmatic nucleus and dorsal hypothalamus. Only in Neoceratodus, however, were important cell populations found in the preoptic area and infundibular hypothalamus, whereas small numbers of faintly reactive neurons were present in the lateral septum and ventral striatum. Fiber labeling was widely distributed in all main brain subdivisions, but was more abundant in regions such as the septum, preoptic area, suprachiasmatic nucleus, lateral hypothalamic area, thalamus, pretectum and tegmentum. Less conspicuous was the innervation of the pallial regions, habenula, optic tectum, rhombencephalic reticular formation and spinal cord. Orexinergic innervation was found in close contact with dopaminergic, noradrenergic and serotoninergic cell groups, homologous to the substantia nigra in the midbrain tegmentum, the locus coeruleus, the nucleus of the solitary tract and the raphe nuclei. Although unique features have been found for lungfishes, the location of orexin immunoreactive elements is largely consistent with that recently reported following a similar approach in amphibians and amniotes, suggesting that the general organization of this peptidergic system occurred in the common ancestor of lungfishes and tetrapods.
Research Interests: Evolution, Immunohistochemistry, Comparative Study, Biological Sciences, Serotonin, and 15 moreNeuropeptides, Interest Groups, Hypothalamus, Animals, Spinal Cord, Fishes, Substantia nigra, Biological evolution, Tyrosine Hydroxylase, Locus coeruleus, Reticular Formation, Brain Chemistry, Suprachiasmatic Nucleus, Preoptic Area, and Ventral Striatum
Research Interests: Physiology, Zoology, Immunohistochemistry, Biological Sciences, Brain Mapping, and 23 moreBrain, Lizards, Hypothalamus, Female, Animals, Spinal Cord, Male, Central Nervous System, Peptides, Amphibians, Medical Physiology, Neurons, Comparative Neuroanatomy, Reticular Formation, Olfactory Bulb, Neural pathways, Comparative Neurology, Trigeminal, Catecholamines, Axons, Neurosciences, Gray Matter, and FMRFamide
The organization of the serotonergic system, one of the most important neurotransmitter systems in the brain, has been carefully analyzed in most vertebrate groups, and major shared characteristics have been described, although traits... more
The organization of the serotonergic system, one of the most important neurotransmitter systems in the brain, has been carefully analyzed in most vertebrate groups, and major shared characteristics have been described, although traits particular to each vertebrate class have also been found. The present study is the first that provides a comprehensive and detailed map of the serotonergic structures in the brain of two representative species of lungfishes, the African lungfish (Protopterus dolloi) and the Australian lungfish (Neoceratodus forsteri), as revealed by immunohistochemistry against serotonin (5-HT). Lungfishes are currently considered the closest living relatives of tetrapods and represent an interesting group for the study of evolutionary traits in the transition from fishes to tetrapods. Distinct groups of serotonin immunoreactive cells were observed in the preoptic area, nucleus of the periventricular organ, pretectum, optic tectum and the long column of the raphe. Fiber labeling was widely distributed in all main brain subdivisions but was more abundant in regions such as the striatum, septum, amygdaloid complex, preoptic area, suprachiasmatic nucleus, lateral hypothalamic area, prethalamus, thalamus, mesencephalic tegmentum and rhombencephalic reticular formation. Comparison of these results with those from other classes of vertebrates highlights numerous common traits shared by most groups of fishes but also reveals that the serotonergic system in lungfishes largely resembles those of amphibians and other tetrapods.
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The recent availability of technologies for high throughput proteome analysis has led to the emergence of integrated mRNA and protein expression data. In one such study by Ideker and co-workers, changes in mRNA and protein abundance... more
The recent availability of technologies for high throughput proteome analysis has led to the emergence of integrated mRNA and protein expression data. In one such study by Ideker and co-workers, changes in mRNA and protein abundance levels were quantified following systematic perturbation of a specific metabolic pathway [1]. The authors calculated an overall Pearson correlation coefficient between changes in mRNA and protein expression of 0.61, however, no change in protein expression was observed for almost 80% of genes reported as having a significant change in mRNA indicating that a complex relationship exists between mRNA and protein expression. To try and address this issue, the data were sorted according to various criteria: protein and mRNA expression ratios, confidence values, length of protein, fraction of cysteine residues and half-life prediction, to try and identify any bias in experimental technique which may affect the correlation. mRNA expression ratio and the confidence value had the strongest affect on how well the data correlated, whilst protein detection was weakly dependent on the fraction of cysteine residues in the protein. Initial investigations have indicated that integrating the data with domain knowledge provides the best opportunity for distinguishing between those transcriptome results which may be interpreted in a straightforward manner and those which should be treated with caution.
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Data analysis in bioinformatics relies heavily on statistics and machine learning. Many of these approaches use simplistic formats for representing real-world objects. Recent computational methods rely on more structured representations.... more
Data analysis in bioinformatics relies heavily on statistics and machine learning. Many of these approaches use simplistic formats for representing real-world objects. Recent computational methods rely on more structured representations. This paper presents an object-oriented approach to model toxicity as an intelligent data type. The intelligent data type representing toxicity is potentially useful for a wide range of bioinformatics methodologies
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In this paper we report outcomes of our computational analysis applied to time-series gene expression data generated by Kagami et al [1]. Gene expression data were generated using Affimetrix chips and validated by quantitative RT-PCR... more
In this paper we report outcomes of our computational analysis applied to time-series gene expression data generated by Kagami et al [1]. Gene expression data were generated using Affimetrix chips and validated by quantitative RT-PCR (reverse transcription-polymerase ...
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In this work, an algorithm based on the Ant System was used for the dynamical resource allocation in a multiple input/output experimentation platform. This platform, which mimics a temperature grid plant, is composed of multiple sensors... more
In this work, an algorithm based on the Ant System was used for the dynamical resource allocation in a multiple input/output experimentation platform. This platform, which mimics a temperature grid plant, is composed of multiple sensors and actuators organized in zones. The use of ants in this application allows the search the best actuator in each sample time. This allowed
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In this work, an algorithm based on the Bacteria Swarm Foraging Optimization was used for the dynamical resource allocation in a multiple input/output experimentation platform. This platform, which mimics a temperature grid plant, is... more
In this work, an algorithm based on the Bacteria Swarm Foraging Optimization was used for the dynamical resource allocation in a multiple input/output experimentation platform. This platform, which mimics a temperature grid plant, is composed of multiple sensors and actuators organized in zones. The use of the bacteria based algorithm in this application allows the search the best actuators in
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This paper analyses the influence of the modulation technique on the size of the grid EMI filter inductor in a full bridge converter for photovoltaic systems. Additionally, the use of an alternative modulation technique is proposed which... more
This paper analyses the influence of the modulation technique on the size of the grid EMI filter inductor in a full bridge converter for photovoltaic systems. Additionally, the use of an alternative modulation technique is proposed which exhibits the best compromise concerning efficiency, current quality and EMI filter size.
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ABSTRACT The Permanent Magnet Synchronous Generator (PMSG) with diode bridge is frequently used in small Wind Energy Conversion Systems (WECS). This configuration is robust and cheap, and therefore suitable for small WECS. In order to... more
ABSTRACT The Permanent Magnet Synchronous Generator (PMSG) with diode bridge is frequently used in small Wind Energy Conversion Systems (WECS). This configuration is robust and cheap, and therefore suitable for small WECS. In order to achieve Maximum Power Point Tracking (MPPT) with no mechanical sensors, it is possible to impose the relationship between the DC voltage and the DC current on the optimum operating points. However, this relationship is difficult to calculate theoretically since the whole system is involved. In fact, as there is no model of the whole system in the literature, the optimum curve I*(L)(V-dc) is obtained with experimental tests or simulations. This paper develops an accurate model of the whole WECS, thereby making it possible to relate the electrical variables to the mechanical ones. With this model, it is possible to calculate the optimum curve I*(L)(V-dc) from commonly-known system parameters and to control the system from the DC side. Experimental results validate the theoretical analysis and show that maximum power is extracted for actual wind speed profiles.
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ABSTRACT Designing adequate control laws for grid-connected inverters with LCL filters is complicated. The power quality standards and the system resonances burden the task. In order to deal with resonances, system damping has to be... more
ABSTRACT Designing adequate control laws for grid-connected inverters with LCL filters is complicated. The power quality standards and the system resonances burden the task. In order to deal with resonances, system damping has to be implemented. Active damping is preferred to passive damping so as to improve the efficiency of the conversion. In addition, paralleled grid-connected inverters in photovoltaic (PV) plants are coupled due to grid impedance. Generally, this coupling is not taken into account when designing the control laws. In consequence, depending on the number of paralleled grid-connected inverters and the grid impedance, the inverters installed in PV plants do not behave as expected. In this paper, the inverters of a PV plant are modeled as a multivariable system. The analysis carried out enables to obtain an equivalent inverter that describes the totality of inverters of a PV plant. The study is validated through simulation and field experiments. The coupling effect is described and the control law design of paralleled grid-connected inverters with LCL filters in PV plants is clarified.
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Page 1. 2694 IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 55, NO. 7, JULY 2008 Transformerless Single-Phase Multilevel-Based Photovoltaic Inverter Roberto González, Eugenio Gubía, Member, IEEE, Jesús ...
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... Index TermsDoubly fed induction generator (DFIG), protec-tion, wind power generation. NOMENCLATURE i Current space vector ... 47 GW in 2004 with a 20% growth in this year [1]. Due to their advantageous characteristics, most of the... more
... Index TermsDoubly fed induction generator (DFIG), protec-tion, wind power generation. NOMENCLATURE i Current space vector ... 47 GW in 2004 with a 20% growth in this year [1]. Due to their advantageous characteristics, most of the grid-connected wind turbines operate at ...
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... The influence of the dip type and instant of occurrence is also studied. Index TermsDoublyfed induction generator (DFIG), protec-tion, wind power generation. NOMENCLATURE i Current space vector. Lm Magnetizing inductance. Ls, Lr... more
... The influence of the dip type and instant of occurrence is also studied. Index TermsDoublyfed induction generator (DFIG), protec-tion, wind power generation. NOMENCLATURE i Current space vector. Lm Magnetizing inductance. Ls, Lr Stator, rotor self-inductance. ...
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AbstractA harmful aspect of adjustable speed drives is the presence of large high-frequency stray currents. The most important, from the view of electromagnetic compatibility, are common-mode currents at the output and input sides of the... more
AbstractA harmful aspect of adjustable speed drives is the presence of large high-frequency stray currents. The most important, from the view of electromagnetic compatibility, are common-mode currents at the output and input sides of the converter. Currents at the ...