Cat(0) and Cat (-1) dimensions of torsion free

We show that a particular free-by-cyclic group has CAT(0) dimension equal to 2, but CAT(-1) dimension equal to 3. We also classify the minimal proper 2-dimensional CAT(0) actions of this group; they correspond, up to scaling, to a 1-parameter family of locally CAT(0) piecewise Euclidean metrics on a fixed presentation complex for the group. This information is used to produce an infinite family of 2-dimensional hyperbolic groups, which do not act properly by isometries on any proper CAT(0) metric space of dimension 2. This family includes a free-by-cyclic group with free kernel of rank 6.

Valuations, intersections et fonctions de Belyi

We present in this article several possibilities to approach the height of an algebraic curve defined over a number field : as an intersection number via the Arakelov theory, as a limit point of the heights of its algebraic points and, finally, using the minimal degree of Belyi functions.

Renormalization and α-limit set for expanding Lorenz maps

We establish a one-to-one correspondence between the renormalizations and proper totally invariant closed sets (i.e., α-limit sets) of expanding Lorenz map, which enable us to distinguish periodic and non-periodic renormalizations. We describe the minimal renormalization by constructing the minimal totally invariant closed set, so that we can define the renormalization operator. Using consecutive renormalizations, we obtain complete topological characteriza- tion of α-limit sets and nonwandering set decomposition. For piecewise linear Lorenz map with slopes ≥ 1, we show that each renormalization is periodic and every proper α-limit set is countable.

Situación del jamón curado en las tendencias nutricionales actuales (transición nutricional)

The definition of nutritional transition could be related to all the aspects involved in human behaviour, genetics and technological changes that show an influence on nutrition. Obesity is considered one of the most important risk factors for human health. Human genetics plays an important role that needs to be defined in more detail to improve the knowledge on pathology of obesity. Dry cured ham has a moderate value of energy density (ED), but this parameter is variable for the different types of dry cured hams and the different commercial preparations. The most important challenge of dry cured ham is the content of salt that should be optimised to arise the minimal concentration without compromise the sensorial quality and the technological possibilities available. On the other hand, the high content of protein and a good ratio polyunsaturated/saturated could be of interest to include dry cured ham in a diet, mainly in the case where the content of fat is moderated or low. Food industry needs to develop new products, improve the information to consumers and to consider the different distribution of population in developed and developing countries.

The interaction of Gram negative bacteria and S. mansoni in mice with experimental Schistosomiasis

Animals (122 mice) were infected each with eighty cercariae of S. mansoni and subsequently challenged intravenously eight weeks later with the following gram-negative organisms. S. typhi, E. coli, Klebsiella-enterobacter species, Proteus mirabilis and Pseudomonas aeruginosa. Enumeration of bacteria in the liver, spleen and blood and S. mansoni from the portal sistem was performed from one to four weeks later in infected animals. A significant difference between infection produced by S. typhi and other gram negative organisms was observed: S. typhi persisted longer in the spleen and liver and could be recovered from S. mansoni worms up to three weeks following bacterial infection. Other gram negative bacteria disappeared from S. mansoni worms after two weeks of initial challenge. Additional animals (51 mice) infected with S. mansoni were given S. typhi, E. coli or sterile saline. After two weeks, animals were sacrificed and the recovery rate of worms from the portal system, and the mesenteric and hepatic oogram were determined. in animals infected with E. coli a significant decrease in the number of worms was observed compared to the saline control group; thirty worms were recovered in the control group compared to two worms in e. coli infected animals. In addition, the patterns of oviposition was significantly different in these latter animals suggesting complete inhibition of this process. Following S. typhi infection the difference in recovery of worms and pattern of oviposition was minimal. These findings suggest a difference in the interaction of various gram negative bacteria and S. mansoni and are consistent with the clinical observation of prolonged salmonella bacteremia in patients with schistosomiasis.

Glomerulonephritis in schistosomiasis with mesangial IgM deposits

Twenty one cases of hepatoesplenic schistosomiasis patients without clinical and laboratory evidence of renal disease, were studied by surgical biopsies using light microscopy and immunofluorescence. The cases were classified histologically as: normal pattern (6 cases); minimal changes (6 cases); and mesangial proliferative glomerulonephritis (9 cases). By the immunofluorescence microscopy using anti IgM, IgG, IgA and C3, the predominant finding in all biopsies, except the normal cases, was granular deposits of IgM in the mesangium along with C3. On the other hand, IgG was present in all cases including normal biopsies along the capillary walls. However IgG was also present in the mesangium only in cases with glomerular lesions. This finding may well be similar to that recently described as IgM mesangial nephropathy. According to our cases a mesangial proliferative glomerulonephritis, characterized by segmental cell proliferation and deposition of IgM in the mesangium, is probably the entity found in the early stages of mansonic schistosomiasis.

Catalan's intervals and realizers of triangulations

The Stanley lattice, Tamari lattice and Kreweras lattice are three remarkable orders defined on the set of Catalan objects of a given size. These lattices are ordered by inclusion: the Stanley lattice is an extension of the Tamari lattice which is an extension of the Kreweras lattice. The Stanley order can be defined on the set of Dyck paths of size n as the relation of being above. Hence, intervals in the Stanley lattice are pairs of non-crossing Dyck paths. In a former article, the second author defined a bijection Φ between pairs of non-crossing Dyck paths and the realizers of triangulations (or Schnyder woods). We give a simpler description of the bijection Φ. Then, we study the restriction of Φ to Tamari’s and Kreweras’ intervals. We prove that Φ induces a bijection between Tamari intervals and minimal realizers. This gives a bijection between Tamari intervals and triangulations. We also prove that Φ induces a bijection between Kreweras intervals and the (unique) realizers of stack triangulations. Thus, Φ induces a bijection between Kreweras intervals and stacktriangulations which are known to be in bijection with ternary trees.

Competitive interactions between species of freshwater snails: I. Laboratory: Ia. General methodology

For the development of laboratory experiments on the competitive interacitons between freshwater snail populations, special snail rooms were set up in the main building of the Research Center "Aggeu Magalhães". In the current paper, the first of a series on this subject, the general methodology of the laboratory work is described in detail. Using indoor cement channels in which a uniform seminatural environment was created, interactions of freshwater snail populations can be studied with minimal interference of the usual variables. Controlled indoor environmental techniques, as described in the current paper, may also be utilized in different types of experiments in malacology, and represent a substantial technical advance in malacological work.

Stock market volatility and learning

Introducing bounded rationality in a standard consumption-based asset pricing model with time separable preferences strongly improves empirical performance. Learning causes momentum and mean reversion of returns and thereby excess volatility, persistence of price-dividend ratios, long-horizon return predictability and a risk premium, as in the habit model of Campbell and Cochrane (1999), but for lower risk aversion. This is obtained, even though our learning scheme introduces just one free parameter and we only consider learning schemes that imply small deviations from full rationality. The findings are robust to the learning rule used and other model features. What is key is that agents forecast future stock prices using past information on prices.

PulseCath iVAC 3LTM hemodynamic performance for simple assisted flow.

The PulseCath iVAC 3L? left ventricular assist device is an option to treat transitory left heart failure or dysfunction post-cardiac surgery. Assisted blood flow should reach up to 3 l/min. In the present in vitro model exact pump flow, depending on various frequencies and afterload was examined. Optimal flow was achieved with inflation/deflation frequencies of about 70-80/min. The maximal flow rate was achieved at about 2.5 l/min with a minimal afterload of 22 mmHg. Handling of the device was easy due to the connection to a standard intra-aortic balloon pump console. With increasing afterload (up to a simulated mean systemic pressure of 66 mmHg) flow rate and cardiac support are in some extent limited.

Importation of Acinetobacter baumannii into a burn unit: a recurrent outbreak of infection associated with widespread environmental contamination.

A burn patient was infected with Acinetobacter baumannii on transfer to the hospital after a terrorist attack. Two patients experienced cross-infection. Environmental swab samples were negative for A. baumannii. Six months later, the bacteria reemerged in 6 patients. Environmental swab samples obtained at this time were inoculated into a minimal mineral broth, and culture results showed widespread contamination. No case of infection occurred after closure of the unit for disinfection.

Bioluminescent sensor proteins for point-of-care therapeutic drug monitoring.

For many drugs, finding the balance between efficacy and toxicity requires monitoring their concentrations in the patient's blood. Quantifying drug levels at the bedside or at home would have advantages in terms of therapeutic outcome and convenience, but current techniques require the setting of a diagnostic laboratory. We have developed semisynthetic bioluminescent sensors that permit precise measurements of drug concentrations in patient samples by spotting minimal volumes on paper and recording the signal using a simple point-and-shoot camera. Our sensors have a modular design consisting of a protein-based and a synthetic part and can be engineered to selectively recognize a wide range of drugs, including immunosuppressants, antiepileptics, anticancer agents and antiarrhythmics. This low-cost point-of-care method could make therapies safer, increase the convenience of doctors and patients and make therapeutic drug monitoring available in regions with poor infrastructure.

Portal vein embolization before right hepatectomy: prospective clinical trial.

OBJECTIVE: To assess the impact of liver hypertrophy of the future liver remnant volume (FLR) induced by preoperative portal vein embolization (PVE) on the immediate postoperative complications after a standardized major liver resection. SUMMARY BACKGROUND DATA: PVE is usually indicated when FLR is estimated to be too small for major liver resection. However, few data exist regarding the exact quantification of sufficient minimal functional hepatic volume required to avoid postoperative complications in both patients with or without chronic liver disease. METHODS: All consecutive patients in whom an elective right hepatectomy was feasible and who fulfilled the inclusion and exclusion criteria between 1998 and 2000 were assigned to have alternatively either immediate surgery or surgery after PVE. Among 55 patients (25 liver metastases, 2 cholangiocarcinoma, and 28 hepatocellular carcinoma), 28 underwent right hepatectomy after PVE and 27 underwent immediate surgery. Twenty-eight patients had chronic liver disease. FLR and estimated rate of functional future liver remnant (%FFLR) volumes were assessed by computed tomography. RESULTS: The mean increase of FLR and %FFLR 4 to 8 weeks after PVE were respectively 44 +/- 19% and 16 +/- 7% for patients with normal liver and 35 +/- 28% and 9 +/- 3% for those with chronic liver disease. All patients with normal liver and 86% with chronic liver disease experienced hypertrophy after PVE. The postoperative course of patients with normal liver who underwent PVE before right hepatectomy was similar to those with immediate surgery. In contrast, PVE in patients with chronic liver disease significantly decreased the incidence of postoperative complications as well as the intensive care unit stay and total hospital stay after right hepatectomy. CONCLUSIONS: Before elective right hepatectomy, the hypertrophy of FLR induced by PVE had no beneficial effect on the postoperative course in patients with normal liver. In contrast, in patients with chronic liver disease, the hypertrophy of the FLR induced by PVE decreased significantly the rate of postoperative complications.

The role of the hypothalamic kisspeptin/GPR54 system in the control of GnRH neurons

Summary : The hypothalamus represents less than 1 % of the total volume of the brain tissue, yet it plays a crucial role in endocrine regulations. Puberty is defined as a process leading to physical, sexual and psychosocial maturation. The hypothalamus is central to this process, via the activation of GnRH neurons. Pulsatile GnRH secretion, minimal during childhood, increases with the onset of puberty. The primary function of GnRH is to regulate the growth, development and function of testes in boys and ovaries in girls, by stimulating the pituitary gland secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Several factors contribute to the timing of puberty, including sex and ethnicity, genetics, dietary intake and energy expenditure. Kisspeptins constitute a family of small peptides arising from the proteolytic cleavage of metastin, a peptide with 54 amino acids initially purified from human placenta. These kisspeptins were the subject of much attention following their discovery because of their antimetastatic properties, but it was more recently that their determining role in the reproductive function was demonstrated. It was shown that kisspeptins are ligands of a receptor, GPR54, whose natural inactivating mutation in humans, or knockout in the mouse, lead to infertility. GnRH neurons play a pivotal role in the central regulation of fertility. Kisspeptin greatly increases GnRH release and GnRH neuron firing activity, but the neurobiological mechanisms for these actions are unknown. Gprotein-coupled receptor 54, the receptor for kisspeptin, is expressed by GnRH neurons as well as other hypothalamic neurons, suggesting that both direct and indirect effects are possible. In the first part of my thesis, we investigated a possible connection between the acceleration of sexual development induced by leptin and hypothalamic metastin neurons. However, the data generated by our preliminary experiments confirmed that the commercially available antibodies are non-specific. This finding constituted a major drawback for our studies, which relied heavily upon the neuroanatomical study of the hypothalamic metastinergic pathways to elucidate their sensitivity to exogenous leptin. Therefore, we decided to postpone any further in vivo experiment until a better antibody becomes available, and focused on in vitro studies to better understand the mechanisms of action of kisspeptins in the modulation of the activity of GnRH neurons. We used two GnRH-expressing neuronal cell lines to investigate the cellular and molecular mechanisms of action of metastin in GnRH neurons. We demonstrated that kisspeptin induces an early activation of the MAP kinase intracellular signaling pathway in both cell lines, whereas the SAP/JNK or the Akt pathways were unaffected. Moreover, we found an increase in GnRH mRNA levels after 6h of metastin stimulation. Thus, we can conclude that kisspeptin regulates GnRH neurons both at the secretion and the gene expression levels. The MAPK pathway is the major pathway activated by metastin in GnRH expressing neurons. Taken together, these data provide the first mechanism of action of kisspeptin on GnRH neurons. Résumé : L'hypothalamus est une zone située au centre du cerveau, dont il représente moins de 1 du volume total. La puberté est la période de transition entre l'enfance et l'age adulte, qui s'accompagne de transformations somatiques, psychologiques, métaboliques et hormonales conduisant à la possibilité de procréer. La fonction principale de la GnRH est la régulation de la croissance, du développement et de la fonction des testicules chez les hommes, et des ovaires chez les femmes en stimulant la sécrétion de l'hormone lutéinisante (LH) et de l'hormone folliculostimulante (FSH) par la glande hypophysaire. Plusieurs facteurs contribuent au déclanchement de la puberté, y compris le sexe et l'appartenance ethnique, la génétique, l'apport alimentaire et la dépense énergétique. Les Kisspeptines constituent une famille de peptides résultant de la dissociation proteolytique de la métastine, un peptide de 54 acides aminés initialement purifié à partir de placenta humain. Ces kisspeptines ont fait l'objet de beaucoup d'attention à la suite de leur découverte en raison de leurs propriétés anti-metastatiques, et c'est plus récemment que leur rôle déterminant dans la fonction reproductive a été démontré. Les kisspeptines sont des ligands du récepteur GPR54, dont la mutation inactivatrice chez l'homme, ou le knockout chez la souris, conduisent à l'infertilité par hypogonadisme hypogonadotrope. Les neurones à GnRH jouent un rôle central dans le règlement des fonctions reproductrices et la kisspeptine stimule l'activité des neurones à GnRH et la libération de GnRH par ces neurones. Toutefois, les mécanismes neurobiologiques de ces actions ne sont pas connus. Dans la première partie de ma thèse, nous avons étudié le lien potentiel entre l'accélération du développement sexuel induite par la leptine et les neurones hypothalamiques à metastine. Les données générées dans cette première série d'expériences ont malheureusement confirmé que les anticorps anti-metastine disponibles dans le commerce sont aspécifiques. Ceci a constitué un inconvénient majeur pour nos études, qui devaient fortement s'appuyer sur l' étude neuroanatomique des neurones hypothalamiques à metastine pour évaluer leur sensibilité à la leptine exogène. Nous avons donc décidé de focaliser nos travaux sur une étude in vitro des mécanismes d'action de la kisspeptine pour moduler l'activité des neurones à GnRH. Nous avons utilisé deux lignées de cellules neuronales exprimant la GnRH pour étudier les mécanismes d'action cellulaires et moléculaires de la metastine dans des neurones. Nous avons ainsi pu démontrer que la kisspeptine induit une activation précoce de la voie f de signalisation de la MAP kinase dans les deux lignées cellulaires, alors que nous n'avons observé aucune activation de la voie de signalisation de la P13 Kinase et de la SAP/JNK. Nous avons en outre démontré une augmentation de l'expression de la GnRH par la stimulation avec la Kisspeptine. L'ensemble de ces données contribue à élucider le mécanisme d'action avec lequel la kisspeptine agit dans les neurones à GnRH, en démontrant un effet sur l'expression génique de la GnRH. Nous pouvons également conclure que la voie de la MAPK est la voie principale activée par la metastine dans les neurones exprimant la GnRH.

Coupling and monotonicity of queueing processes

The main purpose of this work is to give a survey of main monotonicity properties of queueing processes based on the coupling method. The literature on this topic is quite extensive, and we do not consider all aspects of this topic. Our more concrete goal is to select the most interesting basic monotonicity results and give simple and elegant proofs. Also we give a few new (or revised) proofs of a few important monotonicity properties for the queue-size and workload processes both in single-server and multi- server systems. The paper is organized as follows. In Section 1, the basic notions and results on coupling method are given. Section 2 contains known coupling results for renewal processes with focus on construction of synchronized renewal instants for a superposition of independent renewal processes. In Section 3, we present basic monotonicity results for the queue-size and workload processes. We consider both discrete-and continuous-time queueing systems with single and multi servers. Less known results on monotonicity of queueing processes with dependent service times and interarrival times are also presented. Section 4 is devoted to monotonicity of general Jackson-type queueing networks with Markovian routing. This section is based on the notable paper [17]. Finally, Section 5 contains elements of stability analysis of regenerative queues and networks, where coupling and monotonicity results play a crucial role to establish minimal suficient stability conditions. Besides, we present some new monotonicity results for tandem networks.