Extensions and degenerations of spectral triples

For a unital C*-algebra A, which is equipped with a spectral triple and an extension T of A by the compacts, we construct a family of spectral triples associated to T and depending on the two positive parameters (s,t). Using Rieffel's notation of quantum Gromov-Hausdorff distance between compact quantum metric spaces it is possible to define a metric on this family of spectral triples, and we show that the distance between a pair of spectral triples varies continuously with respect to the parameters. It turns out that a spectral triple associated to the unitarization of the algebra of compact operators is obtained under the limit - in this metric - for (s,1) -> (0, 1), while the basic spectral triple, associated to A, is obtained from this family under a sort of a dual limiting process for (1, t) -> (1, 0). We show that our constructions will provide families of spectral triples for the unitarized compacts and for the Podles sphere. In the case of the compacts we investigate to which extent our proposed spectral triple satisfies Connes' 7 axioms for noncommutative geometry.Comment: 40 pages. Addedd in ver. 2: Examples for the compacts and the Podle`s sphere plus comments on the relations to matricial quantum metrics. In ver.3 the word "deformations" in the original title has changed to "degenerations" and some illustrative remarks on this aspect are adde

Galaxy and mass assembly (GAMA) : The wavelength-dependent sizes and profiles of galaxies revealed by MegaMorph

We investigate the relationship between colour and structure within galaxies using a large, volume-limited sample of bright, low-redshift galaxies with optical-near-infrared imaging from the Galaxy AndMass Assembly survey.We fit single-component,wavelength-dependent, elliptical Sérsic models to all passbands simultaneously, using software developed by the MegaMorph project. Dividing our sample by n and colour, the recovered wavelength variations in effective radius (Re) and Sérsic index (n) reveal the internal structure, and hence formation history, of different types of galaxies. All these trends depend on n; some have an additional dependence on galaxy colour. Late-type galaxies (nr 2.5), even though they maintain constant n with wavelength, revealing that ellipticals are a superimposition of different stellar populations associated with multiple collapse and merging events. Processes leading to structures with larger Re must be associated with lower metallicity or younger stellar populations. This appears to rule out the formation of young cores through dissipative gas accretion as an important mechanism in the recent lives of luminous elliptical galaxies.Peer reviewe

Faraday effect and fragmentation of ferromagnetic layers in multilayer Co/Cu(1 1 1) nanofilms

With purpose to investigate influence of magnetically non-active metal layers on the Faraday effect in multilayer Ferromagnetic/Normal metal films, dependences of the Faraday rotation angles of the light polarization plane on magnetic field have been studied in multilayer [Co/Cu] nanofilms. It was revealed that the Faraday rotation φ varies with thickness of the Cu layers dCu. This φ(dCu) dependence consists of the monotonic component, namely a gradual rise of the angle with increase of dCu, and the non-monotonic one represented by two minima. The monotonic changes of the Faraday rotation were satisfactory described in frames of the effective medium method. Two minima are explained with the Co layer’s fragmentation due to influence of size electron quantization in the Cu layers on formation of Co clusters during deposition of the films.publishe

Galaxy And Mass Assembly (GAMA) : stellar mass functions by Hubble type

This work was supported by the Austrian Science Foundation FWF under grant P23946. AWG was supported under the Australian Research Council's funding scheme FT110100263.We present an estimate of the galaxy stellar mass function and its division by morphological type in the local (0.025 < z < 0.06) Universe. Adopting robust morphological classifications as previously presented (Kelvin et al.) for a sample of 3727 galaxies taken from the Galaxy And Mass Assembly survey, we define a local volume and stellar mass limited sub-sample of 2711 galaxies to a lower stellar mass limit of M = 109.0 MΘ. We confirm that the galaxy stellar mass function is well described by a double-Schechter function given by Μ* = 1010.64 MΘ, α1 = 0.43, φ1* = 4.18 dex-1 Mpc-3, α2 = −1.50 and φ2* = 0.74 dex-1 Mpc-3. The constituent morphological-type stellar mass functions are well sampled above our lower stellar mass limit, excepting the faint little blue spheroid population of galaxies. We find approximately 71-4+3 per cent of the stellar mass in the local Universe is found within spheroid-dominated galaxies; ellipticals and S0-Sas. The remaining 29-3+4 per cent falls predominantly within late-type disc-dominated systems, Sab-Scds and Sd-Irrs. Adopting reasonable bulge-to-total ratios implies that approximately half the stellar mass today resides in spheroidal structures, and half in disc structures. Within this local sample, we find approximate stellar mass proportions for E : S0-Sa : Sab-Scd : Sd-Irr of 34 : 37 : 24 :5.Publisher PDFPeer reviewe

The mitochondrial calcium uniporter regulates breast cancer progression via HIF-1\u3b1

Triple-negative breast cancer (TNBC) represents the most aggressive breast tumor subtype. However, the molecular determinants responsible for the metastatic TNBC phenotype are only partially understood. We here show that expression of the mitochondrial calcium uniporter (MCU), the selective channel responsible for mitochondrial Ca(2+) uptake, correlates with tumor size and lymph node infiltration, suggesting that mitochondrial Ca(2+) uptake might be instrumental for tumor growth and metastatic formation. Accordingly, MCU downregulation hampered cell motility and invasiveness and reduced tumor growth, lymph node infiltration, and lung metastasis in TNBC xenografts. In MCU-silenced cells, production of mitochondrial reactive oxygen species (mROS) is blunted and expression of the hypoxia-inducible factor-1α (HIF-1α) is reduced, suggesting a signaling role for mROS and HIF-1α, downstream of mitochondrial Ca(2+) Finally, in breast cancer mRNA samples, a positive correlation of MCU expression with HIF-1α signaling route is present. Our results indicate that MCU plays a central role in TNBC growth and metastasis formation and suggest that mitochondrial Ca(2+) uptake is a potential novel therapeutic target for clinical intervention

Infarct Location and Sleep Apnea: Evaluating the Potential Association in Acute Ischemic Stroke.

Background: The literature about the relationship between obstructive sleep apnea (OSA) and stroke location is conflicting with some studies finding an association and others demonstrating no relationship. Among acute ischemic stroke patients, we sought to examine the relationship between stroke location and the prevalence of OSA; OSA severity based on apnea-hypopnea index (AHI), arousal frequency, and measure of hypoxia; and number of central and obstructive respiratory events. Methods: Data were obtained from patients who participated in a randomized controlled trial (NCT01446913) that evaluated the effectiveness of a strategy of diagnosing and treating OSA among patients with acute ischemic stroke and transient ischemic attack. Stroke location was classified by brain imaging reports into subdivisions of lobes, subcortical areas, brainstem, cerebellum, and vascular territory. The association between acute stroke location and polysomnographic findings was evaluated using logistic regression for OSA presence and negative binomial regression for AHI. Results: Among 73 patients with complete polysomnography and stroke location data, 58 (79%) had OSA. In unadjusted models, no stroke location variable was associated with the prevalence or severity of OSA. Similarly, in multivariable modeling, groupings of stroke location were also not associated with OSA presence. Conclusions: These results indicate that OSA is present in the majority of stroke patients and imply that stroke location cannot be used to identify a group with higher risk of OSA. The results also suggest that OSA likely predated the stroke. Given this high overall prevalence, strong consideration should be given to obtaining polysomnography for all ischemic stroke patients

Diagnosing and Treating Sleep Apnea in Patients With Acute Cerebrovascular Disease

Background Obstructive sleep apnea ( OSA ) is common among patients with acute ischemic stroke and transient ischemic attack. We evaluated whether continuous positive airway pressure for OSA among patients with recent ischemic stroke or transient ischemic attack improved clinical outcomes. Methods and Results This randomized controlled trial among patients with ischemic stroke/transient ischemic attack compared 2 strategies (standard or enhanced) for the diagnosis and treatment of OSA versus usual care over 1 year. Primary outcomes were National Institutes of Health Stroke Scale and modified Rankin Scale scores. Among 252 patients (84, control; 86, standard; 82, enhanced), OSA prevalence was as follows: control, 69%; standard, 74%; and enhanced, 80%. Continuous positive airway pressure use occurred on average 50% of nights and was similar among standard (3.9±2.1 mean hours/nights used) and enhanced (4.3±2.4 hours/nights used; P=0.46) patients. In intention-to-treat analyses, changes in National Institutes of Health Stroke Scale and modified Rankin Scale scores were similar across groups. In as-treated analyses among patients with OSA, increasing continuous positive airway pressure use was associated with improved National Institutes of Health Stroke Scale score (no/poor, -0.6±2.9; some, -0.9±1.4; good, -0.3±1.0; P=0.0064) and improved modified Rankin Scale score (no/poor, -0.3±1.5; some, -0.4±1.0; good, -0.9±1.2; P=0.0237). In shift analyses among patients with OSA, 59% of intervention patients had best neurological symptom severity (National Institutes of Health Stroke Scale score, 0-1) versus 38% of controls ( P=0.038); absolute risk reduction was 21% (number needed to treat, 4.8). Conclusions Although changes in neurological functioning and functional status were similar across the groups in the intention-to-treat analyses, continuous positive airway pressure use was associated with improved neurological functioning among patients with acute ischemic stroke/transient ischemic attack with OS

Mapping genetic determinants of host susceptibility to Pseudomonas aeruginosa lung infection in mice.

Background: P. aeruginosa is one of the top three causes of opportunistic human bacterial infections. The remarkable variability in the clinical outcomes of this infection is thought to be associated with genetic predisposition. However, the genes underlying host susceptibility to P. aeruginosa infection are still largely unknown. Results: As a step towards mapping these genes, we applied a genome wide linkage analysis approach to a mouse model. A large F2 intercross population, obtained by mating P. aeruginosa-resistant C3H/HeOuJ, and susceptible A/J mice, was used for quantitative trait locus (QTL) mapping. The F2 progenies were challenged with a P. aeruginosa clinical strain and monitored for the survival time up to 7 days post-infection, as a disease phenotype associated trait. Selected phenotypic extremes of the F2 distribution were genotyped with high-density single nucleotide polymorphic (SNP) markers, and subsequently QTL analysis was performed. A significant locus was mapped on chromosome 6 and was named P. aeruginosa infection resistance locus 1 (Pairl1). The most promising candidate genes, including Dok1, Tacr1, Cd207, Clec4f, Gp9, Gata2, Foxp1, are related to pathogen sensing, neutrophils and macrophages recruitment and inflammatory processes. Conclusions: We propose a set of genes involved in the pathogenesis of P. aeruginosa infection that may be explored to complement human studie

The polymyxin B-induced transcriptomic response of a clinical, multidrug-resistant Klebsiella pneumoniae involves multiple regulatory elements and intracellular targets

Background: The emergence of multidrug-resistant Klebsiella pneumoniae is a major public health concern. Many K. pneumoniae infections can only be treated when resorting to last-line drugs such as polymyxin B (PB). However, resistance to this antibiotic is also observed, although insufficient information is described on its mode of action as well as the mechanisms used by resistant bacteria to evade its effects. We aimed to study PB resistance and the influence of abiotic stresses in a clinical K. pneumoniae strain using whole transcriptome profiling. Results: We sequenced 12 cDNA libraries of K. pneumoniae Kp13 bacteria, from two biological replicates of the original strain Kp13 (Kp13) and five derivative strains: induced high-level PB resistance in acidic pH (Kp13(pH)), magnesium deprivation (Kp13(Mg)), high concentrations of calcium (Kp13(Ca)) and iron (Kp13(Fe)), and a control condition with PB (Kp13(PolB)). Our results show the involvement of multiple regulatory loci that differentially respond to each condition as well as a shared gene expression response elicited by PB treatment, and indicate the participation of two-regulatory components such as ArcA-ArcB, which could be involved in re-routing the K. pneumoniae metabolism following PB treatment. Modules of co-expressed genes could be determined, which correlated to growth in acid stress and PB exposure. We hypothesize that polymyxin B induces metabolic shifts in K. pneumoniae that could relate to surviving against the action of this antibiotic. Conclusions: We obtained whole transcriptome data for K. pneumoniae under different environmental conditions and PB treatment. Our results supports the notion that the K. pneumoniae response to PB exposure goes beyond damaged membrane reconstruction and involves recruitment of multiple gene modules and intracellular targets.Fundacao de Amparo a Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Lab Nacl Comp Cient, Petropolis, RJ, BrazilFiocruz MS, Ctr Pesquisas Goncalo Moniz, Salvador, BA, BrazilUniv Fed Sao Paulo, Escola Paulista Med, Dept Internal Med, Lab Alerta,Div Infect Dis, Sao Paulo, SP, BrazilUniv Catolica Cordoba, Fac Ingn, CONICET, Cordoba, ArgentinaUniv Fed Sao Paulo, Escola Paulista Med, Dept Internal Med, Lab Alerta,Div Infect Dis, Sao Paulo, SP, BrazilFAPERJ: E-26/110.315/2014FAPESP: 2010/12891-9CAPES: 23038.010041/2013-13Web of Scienc