t-­stories: improving and expanding t-­words

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Evolución de la Estructura en el Universo. Evolution of structure in the universe.

Se analizará la evolución de la estructura en el Universo desde los puntos de vista numérico, estadístico y observacional dando una caracterización de las propiedades globales del Universo en Gran Escala. Para ello se analizarán los mayores catálogos de Galaxias existentes, nuevas observaciones y simulaciones numéricas Cosmológicas de alta resolución. Mediante la aplicación de diferentes métodos capaces de proporcionar información útil acerca de las propiedades del Universo, se pretende aportar significativamente a la comprensión de la dinámica y la características generales de Galaxias y sistemas de Galaxias.

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.

Note on homology of expanding foliations

This note contains some remarks about the homologies that can be associated to a foliation which is invariant and uniformly expanded by a diffeomorphism. We construct a family of 'dynamical' closed currents supported on the foliation which help us relate the geometric volume growth of the leaves under the diffeomorphism with the map induced on homology in the case when these currents have nonzero homology.

Optimized venous return with a self-expanding cannula: from computational fluid dynamics to clinical application.

The Smart canula concept allows for collapsed cannula insertion, and self-expansion within a vein of the body. (A) Computational fluid dynamics, and (B) bovine experiments (76+/-3.8 kg) were performed for comparative analyses, prior to (C) the first clinical application. For an 18F access, a given flow of 4 l/min (A) resulted in a pressure drop of 49 mmHg for smart cannula versus 140 mmHg for control. The corresponding Reynolds numbers are 680 versus 1170, respectively. (B) For an access of 28F, the maximal flow for smart cannula was 5.8+/-0.5 l/min versus 4.0+/-0.1 l/min for standard (P<0.0001), for 24F 5.5+/-0.6 l/min versus 3.2+/-0.4 l/min (P<0.0001), and for 20F 4.1+/-0.3 l/min versus 1.6+/-0.3 l/min (P<0.0001). The flow obtained with the smart cannula was 270+/-45% (20F), 172+/-26% (24F), and 134+/-13% (28F) of standard (one-way ANOVA, P=0.014). (C) First clinical application (1.42 m2) with a smart cannula showed 3.55 l/min (100% predicted) without additional fluids. All three assessment steps confirm the superior performance of the smart cannula design.

Stress Perception in Public Organizations: Expanding the Job Demands - Job Resources Model by Including Public Service Motivation

Although stress has been a longstanding issue in organizations and management studies, it has never been studied in relation to Public Service Motivation. This article therefore aims to integrate PSM into the job demands-job resources model of stress in order to determine whether PSM might contribute to stress in public organizations. Drawing upon original data from a questionnaire in a Swiss municipality, this study unsurprisingly shows that "red tape" is an antecedent of stress perception, whereas satisfaction with organizational support, positive feedback, and recognition significantly decrease the level of perceived stress. Astonishingly, the empirical results show that PSM is positively and significantly related to stress perception. By increasing individuals' expectations towards their jobs, PSM might thus contribute to increased pressure on public agents. Ultimately, this article investigates the "dark side" of PSM, which has been neglected by the literature thus far.

Expanding the phenotype and genotype of female GnRH deficiency.

Context: GnRH deficiency is a rare genetic disorder of absent or partial pubertal development. The clinical and genetic characteristics of GnRH-deficient women have not been well-described. Objective: To determine the phenotypic and genotypic spectrum of a large series of GnRH-deficient women. Design, Setting, and Subjects: Retrospective study of 248 females with GnRH deficiency evaluated at an academic medical center between 1980 and 2010. Main Outcome Measures: Clinical presentation, baseline endogenous GnRH secretory activity, and DNA sequence variants in 11 genes associated with GnRH deficiency. Results: Eighty-eight percent had undergone pubarche, 51% had spontaneous thelarche, and 10% had 1-2 menses. Women with spontaneous thelarche were more likely to demonstrate normal pubarche (P = 0.04). In 27% of women, neuroendocrine studies demonstrated evidence of some endogenous GnRH secretory activity. Thirty-six percent (a large excess relative to controls) harbored a rare sequence variant in a gene associated with GnRH deficiency (87% heterozygous and 13% biallelic), with variants in FGFR1 (15%), GNRHR (6.6%), and PROKR2 (6.6%) being most prevalent. One woman had a biallelic variant in the X-linked gene, KAL1, and nine women had heterozygous variants. Conclusions: The clinical presentation of female GnRH deficiency varies from primary amenorrhea and absence of any secondary sexual characteristics to spontaneous breast development and occasional menses. In this cohort, rare sequence variants were present in all of the known genes associated with GnRH deficiency, including the novel identification of GnRH-deficient women with KAL1 variants. The pathogenic mechanism through which KAL1 variants disrupt female reproductive development requires further investigation.

Manipulating sleep spindles - expanding views on sleep, memory, and disease.

Sleep spindles are distinctive electroencephalographic (EEG) oscillations emerging during non-rapid-eye-movement sleep (NREMS) that have been implicated in multiple brain functions, including sleep quality, sensory gating, learning, and memory. Despite considerable knowledge about the mechanisms underlying these neuronal rhythms, their function remains poorly understood and current views are largely based on correlational evidence. Here, we review recent studies in humans and rodents that have begun to broaden our understanding of the role of spindles in the normal and disordered brain. We show that newly identified molecular substrates of spindle oscillations, in combination with evolving technological progress, offer novel targets and tools to selectively manipulate spindles and dissect their role in sleep-dependent processes.

Glucose transporter-1 deficiency syndrome: the expanding clinical and genetic spectrum of a treatable disorder.

Glucose transporter-1 deficiency syndrome is caused by mutations in the SLC2A1 gene in the majority of patients and results in impaired glucose transport into the brain. From 2004-2008, 132 requests for mutational analysis of the SLC2A1 gene were studied by automated Sanger sequencing and multiplex ligation-dependent probe amplification. Mutations in the SLC2A1 gene were detected in 54 patients (41%) and subsequently in three clinically affected family members. In these 57 patients we identified 49 different mutations, including six multiple exon deletions, six known mutations and 37 novel mutations (13 missense, five nonsense, 13 frame shift, four splice site and two translation initiation mutations). Clinical data were retrospectively collected from referring physicians by means of a questionnaire. Three different phenotypes were recognized: (i) the classical phenotype (84%), subdivided into early-onset (<2 years) (65%) and late-onset (18%); (ii) a non-classical phenotype, with mental retardation and movement disorder, without epilepsy (15%); and (iii) one adult case of glucose transporter-1 deficiency syndrome with minimal symptoms. Recognizing glucose transporter-1 deficiency syndrome is important, since a ketogenic diet was effective in most of the patients with epilepsy (86%) and also reduced movement disorders in 48% of the patients with a classical phenotype and 71% of the patients with a non-classical phenotype. The average delay in diagnosing classical glucose transporter-1 deficiency syndrome was 6.6 years (range 1 month-16 years). Cerebrospinal fluid glucose was below 2.5 mmol/l (range 0.9-2.4 mmol/l) in all patients and cerebrospinal fluid : blood glucose ratio was below 0.50 in all but one patient (range 0.19-0.52). Cerebrospinal fluid lactate was low to normal in all patients. Our relatively large series of 57 patients with glucose transporter-1 deficiency syndrome allowed us to identify correlations between genotype, phenotype and biochemical data. Type of mutation was related to the severity of mental retardation and the presence of complex movement disorders. Cerebrospinal fluid : blood glucose ratio was related to type of mutation and phenotype. In conclusion, a substantial number of the patients with glucose transporter-1 deficiency syndrome do not have epilepsy. Our study demonstrates that a lumbar puncture provides the diagnostic clue to glucose transporter-1 deficiency syndrome and can thereby dramatically reduce diagnostic delay to allow early start of the ketogenic diet.

Routine use of self-expanding venous cannulas for cardiopulmonary bypass: benefits and pitfalls in 100 consecutive cases.

OBJECTIVE: Assess the performance of self-expanding venous cannulas for routine use in open-heart surgery. METHODS: Prospective study in 100 unselected consecutive patients undergoing open-heart surgery with either remote or central smart venous cannulation. RESULTS: The study focuses on the 76 consecutive adult patients (mean age 59.2+/-17.3 years; 60 males, 16 females) undergoing surgical procedures with total cardiopulmonary bypass for either valve procedures (42/76 patients=55.3%), ascending aorta and arch repair (20/76 patients=26.3%), coronary artery revascularization (13/76 patients=17.1%) or other procedures (11/76 patients=14.5%) with 14/76 patients (18.4%) undergoing redo surgery and 6/76 patients (7.9%) undergoing small access surgery. The mean pump flow achieved by gravity drainage alone accounted for 5.0+/-0.6l/min (=114% of target) in the entire study population (n=76) as compared to the calculated, theoretical pump flow of 4.4+/-0.5l/min (p<0.0001). For the femoral cannulation sub-group (n=35) pump flow achieved by gravity drainage alone accounted for 4.9+/-0.6l/min (=114% of target) as compared to the calculated theoretical pump flow of 4.3+/-0.4l/min (p<0.0001). The corresponding numbers for trans-subclavian cannulation (n=7) are 5.2+/-0.5l/min (111%) for the pump flow achieved by gravity drainage as compared to the theoretical target flow of 4.7+/-0.4l/min. For the central cannulation sub-group (n=34) mean flow achieved by gravity drainage with a self-expanding venous cannula accounted for 5.1+/-0.7l/min (=116% of target) as compared to the calculated theoretical flow of 4.4+/-0.6l/min (p<0.0001). CONCLUSION: Full or more than target flow was achieved in 97% of the patients studied undergoing CPB with self-expanding venous cannulas and gravity drainage. Remote venous cannulation with self-expanding cannulas provides similar flows as central cannulation. Augmentation of venous return is no longer necessary.

Expanding view of phenotype and oxidative stress in Friedreich's ataxia patients with and without idebone.

Friedreich's ataxia (FRDA), the most common autosomal recessive ataxia, is characterised by progressive ataxia with dysarthria of speech, loss of deep-tendon reflexes, impaired vibratory and proprioceptive sensations and corticospinal weakness with a Babinski's sign. Patients eventually also develop kyphoscoliosis, cardiomyopathy and diabetes mellitus. The disease is a GAA repeat disorder resulting in severely reduced levels of frataxin, with secondary increased sensitivity to oxidative stress. The anti-oxidative drug, idebenone, is effective against FRDA-associated cardiomyopathy. We provide detailed clinical, electrophysiological and biochemical data from 20 genetically confirmed FRDA patients and have analysed the relationship between phenotype, genotype and malondialdehyde (MDA), which is a marker of superoxide formation. We assessed the effects of idebenone biochemically by measuring blood MDA and clinically by serial measurements of the International Cooperative Ataxia Rating Scale (ICARS). The GAA repeat length influenced the age at onset (p <0.001), the severity of ataxia (p = 0.02), the presence of cardiomyopathy (p = 0.04) and of low-frequency hearing loss (p = 0.009). Multilinear regression analysis showed (p = 0.006) that ICARS was dependent on the two variables of disease duration (p = 0.01) and size of the GAA expansion (p = 0.02). We found no correlation to bilateral palpebral ptosis, visual impairment, diabetes mellitus or skeletal deformities, all of which appear to be signs of disease progression rather than severity. We discuss more thoroughly two underrecognised clinical findings: palpebral ptosis and GAA length-dependent low-frequency hearing loss. The average ICARS remained unchanged in 10 patients for whom follow-up on treatment was available (mean 2.9 years), whereas most patients treated with idebenone reported an improvement in dysarthria (63%), hand dexterity (58%) and fatigue (47%) after taking the drug for several weeks or months. Oxidative stress analysis showed an unexpected increase in blood MDA levels in patients on idebenone (p = 0.04), and we discuss the putative underlying mechanism for this result, which could then explain the unique efficacy of idebenone in treating the FRDA-associated cardiomyopathy, as opposed to other antioxidative drugs. Indeed, idebenone is not only a powerful stimulator of complexes II and III of the respiratory chain, but also an inhibitor of complex I activity, then promoting superoxide formation. Our preliminary clinical observations are the first to date supporting an effect of idebenone in delaying neurological worsening. Our MDA results point to the dual effect of idebenone on oxidative stress and to the need for controlled studies to assess its potential toxicity at high doses on the one hand, and to revisit the exact mechanisms underlying the physiopathology of Friedreich's ataxia on the other hand, while recent reports suggest non-oxidative pathophysiology of the disease.

Self-expanding mini-cannula for remote perfusion with pediatric scenarios.

The aim of this report is to address the benefits of the minimal invasive venous drainage in a pediatric cardio surgical scenario. Juvenile bovine experiments (67.4+/-11 kg) were performed. The right atrium was cannulated in a trans-jugular way by using the self-expandable (Smart Stat, 12/20F, 430 mm) venous cannula (Smartcannula LLC, Lausanne, Switzerland) vs. a 14F 250 mm (Polystan Lighthouse) standard pediatric venous cannula. Establishing the cardiopulmonary bypass (CPB), the blood flows were assessed for 20 mmHg, 30 mmHg and 40 mmHg of driving pressure. Venous drainage (flow in l/min) at 20 mmHg, 30 mmHg, and 40 mmHg drainage load was 0.26+/-0.1, 0.35+/-0.2 and 0.28+/-0.08 for the 14F standard vs. 1.31+/-0.22, 1.35+/-0.24 and 1.9+/-0.2 for the Smart Stat 12/20F cannula. The 43 cm self-expanding 12/20F Smartcannula outperforms the 14F standard cannula. The results described herein allow us to conclude that usage of the self-expanding Smartcannula also in the pediatric patients improves the flow and the drainage capacity, avoiding the insufficient and excessive drainage. We believe that similar results may be expected in the clinical settings.