Combined intermittent hypoxia and surface muscle electrostimulation as a method to increase peripheral blood progenitor cell concentration.

Background: Our goal was to determine whether short-term intermittent hypoxia exposure, at a level well tolerated by healthy humans and previously shown by our group to increase EPO and erythropoiesis, could mobilizehematopoietic stem cells (HSC) and increase their presence in peripheral circulation. Methods: Four healthy male subjects were subjected to three different protocols: one with only a hypoxic stimulus (OH), another with a hypoxic stimulus plus muscle electrostimulation (HME) and the third with only muscle electrostimulation (OME). Intermittent hypobaric hypoxia exposureconsisted of only three sessions of three hours at barometric pressure 540 hPa (equivalent to an altitude of 5000 m) for three consecutive days, whereas muscular electrostimulation was performed in two separate periods of 25 min in each session. Blood samples were obtained from an antecubital vein on three consecutive days immediately before the experiment and 24 h, 48 h, 4 days and 7 days after the last day of hypoxic exposure. Results: There was a clear increase in the number of circulating CD34+ cells after combined hypobaric hypoxia and muscular electrostimulation. This response was not observed after the isolated application of the same stimuli. Conclusion: Our results open a new application field for hypobaric systems as a way to increase efficiency in peripheral HSC collection.

Erosió hídrica en vinya per a producció de vi d'alta qualitat en zona mediterrània (Anoia-Penedès): quantificació de les pèrdues de nutrients per erosió del sòl i implicacions

La vinya, malgrat que no és una planta exigent pel que fa als sòls, es veu afectada per la pèrdua de sed per causa de l'erosió hídrica. En aquest treball es presenten uns primers resultats de mesures de pèrdues de sed en condicions reals de camp. Les parcel les control són de grans dimensions, conreades segons els costums de la zona. Com a referencia es prenen les pèrdues de sòl mitjanes, calculades a partir de l'USLE, per al conreu de vinya. Es determinen, a més de les pèrdues globals de sòlids, les de nutrients que això comporta. Tenint en compte que la metodologia emprada en el camp i en el laboratori condueix a resultats per defecte, les pèrdues mesurades del període de l'any de màximes pluges (tardor) són, de mitjana, de 13 Mg ha-1 en un sistema de cultiu tradicional i fins a 100 Mg ha-1 en un sistema de cultiu emparrat. La importància del problema a curt termini encareix els factors de producció i fa perillar la sostenibilitat de la vinya a llarg termini.

The offspring of the diabetic mother--short- and long-term implications.

In the 1980s, David Barker and Colleagues proposed that the major causes of cardiovascular and metabolic diseases have their roots in early development. There is now robust evidence that an hyperglycemic intrauterine environment is responsible not only for significant short-term morbidity in the fetus and the neonate but also for an increased risk of developing diabetes as well as other chronic, noncommunicable diseases at adulthood. The risk is higher in pregestational diabetes, but unrecognized and/or poorly managed gestational diabetes (GDM) may have similar consequences. Although a relatively clear picture of the pathogenesis of the fetal and neonatal complications of maternal diabetes and of their interrelationship is available today, the intimate molecular mechanisms involved in the long term are far from being understood. While the rate of GDM is sharply increasing in association with the pandemic of obesity and of type 2 diabetes over the world, we review here the current understanding of short- and long-term outcomes of fetuses exposed to a diabetic environment.

Hints for a fast precessing relativistic radio jet in LS I + 61° 303

Here we discuss two consecutive MERLIN observations of the X-ray binary LS I +61° 303 . The first observation shows a double-sided jet extending up to about 200 AU on both sides of a central source. The jet shows a bent S-shaped structure similar to the one displayed by the well-known precessing jet of SS 433 . The precession suggested in the first MERLIN image becomes evident in the second one, showing a one-sided bent jet significantly rotated with respect to the jet of the day before. We conclude that the derived precession of the relativistic (beta=0.6) jet explains puzzling previous VLBI results. Moreover, the fact that the precession is fast could be the explanation of the never understood short term (days) variability of the associated gamma-ray source 2CG 135+01 / 3EG J0241+6103

Neural correlates of language learning in adults

The human language-learning ability persists throughout life, indicating considerable flexibility at the cognitive and neural level. This ability spans from expanding the vocabulary in the mother tongue to acquisition of a new language with its lexicon and grammar. The present thesis consists of five studies that tap both of these aspects of adult language learning by using magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) during language processing and language learning tasks. The thesis shows that learning novel phonological word forms, either in the native tongue or when exposed to a foreign phonology, activates the brain in similar ways. The results also show that novel native words readily become integrated in the mental lexicon. Several studies in the thesis highlight the left temporal cortex as an important brain region in learning and accessing phonological forms. Incidental learning of foreign phonological word forms was reflected in functionally distinct temporal lobe areas that, respectively, reflected short-term memory processes and more stable learning that persisted to the next day. In a study where explicitly trained items were tracked for ten months, it was found that enhanced naming-related temporal and frontal activation one week after learning was predictive of good long-term memory. The results suggest that memory maintenance is an active process that depends on mechanisms of reconsolidation, and that these process vary considerably between individuals. The thesis put special emphasis on studying language learning in the context of language production. The neural foundation of language production has been studied considerably less than that of perceptive language, especially on the sentence level. A well-known paradigm in language production studies is picture naming, also used as a clinical tool in neuropsychology. This thesis shows that accessing the meaning and phonological form of a depicted object are subserved by different neural implementations. Moreover, a comparison between action and object naming from identical images indicated that the grammatical class of the retrieved word (verb, noun) is less important than the visual content of the image. In the present thesis, the picture naming was further modified into a novel paradigm in order to probe sentence-level speech production in a newly learned miniature language. Neural activity related to grammatical processing did not differ between the novel language and the mother tongue, but stronger neural activation for the novel language was observed during the planning of the upcoming output, likely related to more demanding lexical retrieval and short-term memory. In sum, the thesis aimed at examining language learning by combining different linguistic domains, such as phonology, semantics, and grammar, in a dynamic description of language processing in the human brain.

Pituitary-thyroid axis in short- and long-term experimental diabetes mellitus

Short-term experimental diabetes mellitus (DM) produces a significant decrease in serum thyroid hormones, a decreased or normal serum thyroid-stimulating hormone (TSH) and a reduction in hepatic and renal T4-5'-deiodination. However, little is known about the effects of chronic diabetes mellitus on the pituitary-thyroid axis function. We evaluated the changes induced by very short-term (6 days), short-term (15 days) and chronic (6 months) streptozotocin-induced diabetes mellitus in 3-month old female Dutch-Miranda rat serum T4, serum TSH and T4-5'-deiodinase activity in the thyroid and pituitary glands. Serum hormones were determined by specific radioimmunoassays. Iodothyronine-5'-deiodinase activities were assayed in the thyroid and pituitary microsomal fractions using 2 µM T4 as substrate. Mean serum T4 was significantly decreased from 3.3 to 2.0 µg/dl 6 days after diabetes mellitus induction, and from 2.2 to 1.5 µg/dl after 15 days of DM, with no significant changes in serum TSH, indicating a decreased pituitary TSH responsiveness to the diminished suppression by T4, even though pituitary T4-5'-deiodinase activity was unchanged. Thyroid T4-5'-deiodinase was unchanged after 6 days of diabetes mellitus, but was significantly increased from 20.6 to 37.0 pmol T3/mg protein after 15 days. Six months after diabetes mellitus induction, both serum T4 and thyroid T4-5'-deiodinase returned to normal ranges and serum TSH was unchanged, although pituitary T4-5'-deiodinase was now significantly decreased from 2.7 to 1.7 pmol T3/mg protein. These findings indicate that some kind of adaptation to chronic insulinopenia may occur at the thyroid level, but this does not seem to be true for the pituitary

The brain decade in debate: I. Neurobiology of learning and memory

This article is a transcription of an electronic symposium in which some active researchers were invited by the Brazilian Society for Neuroscience and Behavior (SBNeC) to discuss the last decade's advances in neurobiology of learning and memory. The way different parts of the brain are recruited during the storage of different kinds of memory (e.g., short-term vs long-term memory, declarative vs procedural memory) and even the property of these divisions were discussed. It was pointed out that the brain does not really store memories, but stores traces of information that are later used to create memories, not always expressing a completely veridical picture of the past experienced reality. To perform this process different parts of the brain act as important nodes of the neural network that encode, store and retrieve the information that will be used to create memories. Some of the brain regions are recognizably active during the activation of short-term working memory (e.g., prefrontal cortex), or the storage of information retrieved as long-term explicit memories (e.g., hippocampus and related cortical areas) or the modulation of the storage of memories related to emotional events (e.g., amygdala). This does not mean that there is a separate neural structure completely supporting the storage of each kind of memory but means that these memories critically depend on the functioning of these neural structures. The current view is that there is no sense in talking about hippocampus-based or amygdala-based memory since this implies that there is a one-to-one correspondence. The present question to be solved is how systems interact in memory. The pertinence of attributing a critical role to cellular processes like synaptic tagging and protein kinase A activation to explain the memory storage processes at the cellular level was also discussed.

Aberrant crypt foci and colon cancer: comparison between a short- and medium-term bioassay for colon carcinogenesis using dimethylhydrazine in Wistar rats

Aberrant crypt foci (ACF) in the colon of carcinogen-treated rodents are considered to be the earliest hallmark of colon carcinogenesis. In the present study the relationship between a short-term (4 weeks) and medium-term (30 weeks) assay was assessed in a model of colon carcinogenesis induced by dimethylhydrazine (DMH) in the rat. Six-week-old male Wistar rats were given subcutaneous injections of DMH (40 mg/kg) twice a week for 2 weeks and killed at the end of the 4th or 30th week. ACF were scored for number, distribution pattern along the colon and crypt multiplicity in 0.1% methylene-blue whole-mount preparations. ACF were distinguished from normal crypts by their larger size and elliptical shape. The incidence, distribution and morphology of colon tumors were recorded. The majority of ACF were present in the middle and distal colon of DMH-treated rats and their number increased with time. By the 4th week, 91.5% ACF were composed of one or two crypts and 8.5% had three or more crypts, while by the 30th week 46.9% ACF had three or more crypts. Thus, a progression of ACF consisting of multiple crypts was observed from the 4th to the 30th week. Nine well-differentiated adenocarcinomas were found in 10 rats by the 30th week. Seven tumors were located in the distal colon and two in the middle colon. No tumor was found in the proximal colon. The present data indicate that induction of ACF by DMH in the short-term (4 weeks) assay was correlated with development of well-differentiated adenocarcinomas in the medium-term (30 weeks) assay.

Inhibition of PKC-dependent extracellular Ca2+ entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas

We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT2R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT2R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca2+-free medium or the subsequent tonic constrictions induced by the addition of Ca2+ in the absence of agonists. Thus, the contractions induced by Ca2+ release from intracellular stores and Ca2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca2+. Neither levels of angiotensins nor of AT2R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca2+ entry.

Resuming growth in Latin America: short and long term policies

The authors of this paper assert that the paralysis of the state generated by the crises of the 1970s and 1980s deprived the economies of the region of an important lever to resume and sustain growth. They thus maintain that to overcome stagnation it will be necessary to reconstruct the state's capacity to implement pro-growth policies. Following Keynes and Kalecki's ideas, but also classical development economists, the authors argue, first, that short-term macroeconomic policies, to reduce unemployment and to increase the degree of capacity utilization, should be used to promote the generation of profits to firms and to wake up entrepreneurs' animal spirits. Short-term expansionary policies should be coupled with measures to improve competitiveness and avoid balance of payments problems. They also claim that alternatives to the liberal programme will fail unless a pro-growth strategy is adopted which includes both short- and long-term policies. They thus propose that long-term policies must complete the package, signaling: a) sustained increases of effective demand in the future; and b) investment priorities to ensure that capacities will be created in strategic sectors and branches of the economy.

Entwicklung eines Windleistungprognosemodells zur Verbesserung der Kraftwerkseinsatzplanung

Die Maßnahmen zur Förderung der Windenergie in Deutschland haben wichtige Anstöße zur technologischen Weiterentwicklung geliefert und die Grundlagen für den enormen Anlagenzubau geschaffen. Die installierte Windleistung hat heute eine beachtliche Größenordnung erreicht und ein weiteres Wachstum in ähnlichen Dimensionen ist auch für die nächsten Jahre zu erwarten. Die aus Wind erzeugte elektrische Leistung deckt bereits heute in einigen Netzbereichen die Netzlast zu Schwachlastzeiten. Dies zeigt, dass die Windenergie ein nicht mehr zu vernachlässigender Faktor in der elektrischen Energieversorgung geworden ist. Im Rahmen der Kraftwerkseinsatzplanung sind Betrag und Verlauf der Windleistung des folgenden Tages mittlerweile zu wichtigen und zugleich schwierig zu bestimmenden Variablen geworden. Starke Schwankungen und falsche Prognosen der Windstromeinspeisung verursachen zusätzlichen Bedarf an Regel- und Ausgleichsleistung durch die Systemführung. Das im Rahmen dieser Arbeit entwickelte Prognosemodell liefert die zu erwartenden Windleistungen an 16 repräsentativen Windparks bzw. Gruppen von Windparks für bis zu 48 Stunden im Voraus. Aufgrund von prognostizierten Wetterdaten des deutschen Wetterdienstes (DWD) werden die Leistungen der einzelnen Windparks mit Hilfe von künstlichen neuronalen Netzen (KNN) berechnet. Diese Methode hat gegenüber physikalischen Verfahren den Vorteil, dass der komplexe Zusammenhang zwischen Wettergeschehen und Windparkleistung nicht aufwendig analysiert und detailliert mathematisch beschrieben werden muss, sondern anhand von Daten aus der Vergangenheit von den KNN gelernt wird. Das Prognosemodell besteht aus zwei Modulen. Mit dem ersten wird, basierend auf den meteorologischen Vorhersagen des DWD, eine Prognose für den Folgetag erstellt. Das zweite Modul bezieht die online gemessenen Leistungsdaten der repräsentativen Windparks mit ein, um die ursprüngliche Folgetagsprognose zu verbessern und eine sehr genaue Kurzzeitprognose für die nächsten drei bis sechs Stunden zu berechnen. Mit den Ergebnissen der Prognosemodule für die repräsentativen Standorte wird dann über ein Transformationsmodell, dem so genannten Online-Modell, die Gesamteinspeisung in einem größeren Gebiet berechnet. Das Prognoseverfahren hat seine besonderen Vorzüge in der Genauigkeit, den geringen Rechenzeiten und den niedrigen Betriebskosten, da durch die Verwendung des bereits implementierten Online-Modells nur eine geringe Anzahl von Vorhersage- und Messstandorten benötigt wird. Das hier vorgestellte Prognosemodell wurde ursprünglich für die E.ON-Netz GmbH entwickelt und optimiert und ist dort seit Juli 2001 im Einsatz. Es lässt sich jedoch auch leicht an andere Gebiete anpassen. Benötigt werden dazu nur die Messdaten der Leistung ausgewählter repräsentativer Windparks sowie die dazu gehörenden Wettervorhersagen, um die KNN entsprechend zu trainieren.

Hints for a fast precessing relativistic radio jet in LS I + 61° 303

Here we discuss two consecutive MERLIN observations of the X-ray binary LS I +61° 303 . The first observation shows a double-sided jet extending up to about 200 AU on both sides of a central source. The jet shows a bent S-shaped structure similar to the one displayed by the well-known precessing jet of SS 433 . The precession suggested in the first MERLIN image becomes evident in the second one, showing a one-sided bent jet significantly rotated with respect to the jet of the day before. We conclude that the derived precession of the relativistic (beta=0.6) jet explains puzzling previous VLBI results. Moreover, the fact that the precession is fast could be the explanation of the never understood short term (days) variability of the associated gamma-ray source 2CG 135+01 / 3EG J0241+6103

El risc dinàmic: concepte, mesura i determinants econòmics

Aquesta tesi té la intenció de realitzar una contribució metodològica en el camp de la direcció estratègica, per mitjà de tres objectius: la revisió del concepte de risc ex post o realitzat per l'àmbit de la direcció estratègica; la concreció d'aquest concepte en una mesura de risc vàlida; i l'exploració de les possibilitats i l'interès de la descomposició del risc en diferents determinants que puguin explicar-ne la seva naturalesa. El primer objectiu es du a terme prenent com a base el concepte intuïtiu de risc i revisant la literatura en els camps més afins, especialment en la teoria comportamental de la decisió i la direcció estratègica. L'anàlisi porta a formular el risc ex post d'una activitat com el grau en què no s'han assolit els objectius per a aquesta activitat. La concreció d'aquesta definició al camp de la direcció estratègica implica que els objectius han de portar a l'obtenció de l'avantatge competitiu sostenible, el que descobreix l'interès de realitzar la mesura del risc a curt termini, és a dir, estàticament, i a llarg termini, és a dir, dinàmicament, pel que es defineix una mesura de Risc Estàtic i una altra de Risc dinàmic, respectivament. En l'anàlisi apareixen quatre dimensions conceptuals bàsiques a incorporar en les mesures: sign dependence, relativa, longitudinal i path dependence. Addicionalment, la consideració de que els resultats puguin ser cardinals o ordinals justifica que es formulin les dues mesures anteriors per a resultats cardinals i, en segon lloc, per a resultats ordinals. Les mesures de risc que es proposen sintetitzen els resultats ex post obtinguts en una mesura de centralitat relativa dels resultats, el Risc Estàtic, i una mesura de la tendència temporal dels resultats, el Risc Dinàmic. Aquesta proposta contrasta amb el plantejament tradicional dels models esperança-variància. Les mesures desenvolupades s'avaluen amb un sistema de propietats conceptuals i tècniques que s'elaboren expressament en la tesi i que permeten demostrar el seu gra de validesa i el de les mesures existents en la literatura, destacant els problemes de validesa d'aquestes darreres. També es proporciona un exemple teòric il·lustratiu de les mesures proposades que dóna suport a l'avaluació realitzada amb el sistema de propietats. Una contribució destacada d'aquesta tesi és la demostració de que les mesures de risc proposades permeten la descomposició additiva del risc si els resultats o diferencials de resultats es descomponen additivament. Finalment, la tesi inclou una aplicació de les mesures de Risc Estàtic i Dinàmic cardinals, així com de la seva descomposició, a l'anàlisi de la rendibilitat del sector bancari espanyol, en el període 1987-1999. L'aplicació il·lustra la capacitat de les mesures proposades per a analitzar la manifestació de l'avantatge competitiu, la seva evolució i naturalesa econòmica. En les conclusions es formulen possibles línees d'investigació futures.

Serviceability behaviour of fibre reinforced polymer reinforced concrete beams

El uso de materiales compuestos de matriz polimérica (FRP) emerge como alternativa al hormigón convencionalmente armado con acero debido a la mayor resistencia a la corrosión de dichos materiales. El presente estudio investiga el comportamiento en servicio de vigas de hormigón armadas con barras de FRP mediante un análisis teórico y experimental. Se presentan los resultados experimentales de veintiséis vigas de hormigón armadas con barras de material compuesto de fibra de vidrio (GFRP) y una armada con acero, todas ellas ensayadas a flexión de cuatro puntos. Los resultados experimentales son analizados y comparados con algunos de los modelos de predicción más significativos de flechas y fisuración, observándose, en general, una predicción adecuada del comportamiento experimental hasta cargas de servicio. El análisis de sección fisurada (CSA) estima la carga última con precisión, aunque se registra un incremento de la flecha experimental para cargas superiores a las de servicio. Esta diferencia se atribuye a la influencia de las deformaciones por esfuerzo cortante y se calcula experimentalmente. Se presentan los aspectos principales que influyen en los estados límites de servicio: tensiones de los materiales, ancho máximo de fisura y flecha máxima permitida. Se presenta una metodología para el diseño de dichos elementos bajo las condiciones de servicio. El procedimiento presentado permite optimizar las dimensiones de la sección respecto a metodologías más generales.

Controlled trial of the short- and long-term effect of psychological treatment of post-partum depression 2. Impact on the mother-child relationship and child outcome

Background: Postnatal depression is associated with adverse child cognitive and socio-emotional outcome. It is not known whether psychological treatment affects the quality of the mother-child relationship and child outcome. Aims: To evaluate the effect of three psychological treatments on the mother-child relationship and child outcome. Method: Women with post-partum depression (n=193) were assigned randomly to routine primary care, non-directive counselling, cognitive-behavioural therapy or psychodynamic therapy The women and their children, were assessed at 43, [8 and 60 months post-partum. Results: Indications of a positive benefit were limited. All three treatments had a significant benefit on maternal reports of early difficulties in relationships with the infants, counselling gave better infant emotional and behaviour ratings at 18 months and more sensitive early mother-infant interactions. The treatments had no significant impact on maternal management of early infant behaviour problems, security of infant-mother attachment. Infant cognitive development or any child outcome at 5 years. Conclusions: Early intervention was of short-term benefit to the mother-child relationship and infant behaviour problems. More-prolonged intervention may be needed. Health visitors could deliver this.