New results on q-positivity

In this paper we discuss symmetrically self-dual spaces, which are simply real vector spaces with a symmetric bilinear form. Certain subsets of the space will be called q-positive, where q is the quadratic form induced by the original bilinear form. The notion of q-positivity generalizes the classical notion of the monotonicity of a subset of a product of a Banach space and its dual. Maximal q-positivity then generalizes maximal monotonicity. We discuss concepts generalizing the representations of monotone sets by convex functions, as well as the number of maximally q-positive extensions of a q-positive set. We also discuss symmetrically self-dual Banach spaces, in which we add a Banach space structure, giving new characterizations of maximal q-positivity. The paper finishes with two new examples.Comment: 18 page

Compulsory Secondary Education students explanations regarding phenomena related to the volume of liquid moved by a immersed solid, to the density and to the buoyancy

En este artículo se realiza un diagnóstico de las explicaciones del alumnado respecto al volumen de líquido que desplaza un sólido en inmersión y a la relación entre flotabilidad de los cuerpos y la densidad. El estudio se plantea con estudiantes de cuarto curso de Educación Secundaria Obligatoria (ESO) a comienzos del curso escolar, donde el dominio de los conceptos de volumen de líquido desplazado y de densidad son un pre-requisito para comprender fenómenos que se estudiaran durante el desarrollo del curso (valor del empuje y dependencia del equilibrio entre las fuerzas peso y empuje para justificar la flotabilidad de los cuerpos). Los resultados indican que los estudiantes llegan a este nivel con concepciones sobre las variables que influyen en el volumen de líquido desplazado similares a las de los escolares de Primaria. La dependencia del contexto de sus explicaciones pone de manifiesto que, para explicar la flotabilidad de un sólido en un líquido, no siempre llegan a aplicar el criterio de comparación de densidades. Estas dificultades se acentúan en el caso concreto de la flotación-inmersión de un submarino, como cuerpo sólido que es capaz de variar su densidad media.This paper presents a diagnosis of the explanations that the students give regarding the volume of fluid that moves an immersed solid and regarding the relationship between buoyancy of objects and its density. The study sets out with students from fourth year of Compulsory Secondary Education (ESO) at the beginning of the school year. In this respect, the knowledge of concepts displaced liquid volume and density are a pre-requisite for understanding phenomena studied during the school year (value of thrust and balance between weight and thrust forces to justify the buoyancy of objects). Results indicate that students reach this level with conceptions of the variables that influence the volume of displaced liquid that are similar to those of primary school children ones. The context-sensitive explanations show that students do not always apply the densities comparison criterion to explain the buoyancy of a solid in a liquid. These difficulties are all the greater in the case of buoyancyimmersion of a submarine, as a solid that is able to vary its average density

Tjänstekvalitet och kundtillfredsställelse på restaurang Solna

En global konkurrens, kunder med höga krav och en ständigt växande medvetenhet har medfört en ökad satsning på kvalitetsutveckling. Kvalitetsutveckling innebär ett ständigt utvecklings- och förbättringsarbete. Syftet med denna empiriska studie är att mäta restaurang Solnas tjänstekvalitet och kundtillfredsställelse. Delsyftet är att mäta tjänstekvaliteten och ge förslag till hur denna kan vidareutvecklas. Förslagen grundar sig på den teori jag beskrivit som berör kvalitet, tjänster, kunden och kundmätningar. Kvalitet spelar huvudrollen i den teoretiska referensramen. Problemställningen är om Solna uppfattas kvalitetsmässigt som bra, och om en god kundtillfredsställelse uppnås och hur företaget kunde förbättra tjänstekvaliteten så att den optimala kundtillfredsställelsen kan uppnås. Som datainsamlingsmetod används den kvantitativa metoden. Undersökningen görs med stöd av ett frågeformulär och resultaten analyseras statistiskt. Frågeformuläret består av 26 stycken frågor, både slutna och öppna. Dessa frågor berör områden som kvaliteten på den utförda tjänsten, maten och servicen. Resultaten av undersökningen är mycket positiva. Solnas kunder är tillfredsställda och tjänstekvaliteten anses vara god. Några brister finns dock. Kommunikation mellan kund och personal är ett område som kunde förbättras och utvecklas. Personalen kunde uppmärksamma kunden under hela processen, från början till slut. Man kunde motivera personalen med work shop- kvällar då personalen kunde komma med sina egna tankar om hur tjänstekvaliteten kunde se ut på restaurangen. Personalen kunde också motiveras med t.ex. presentkort till en restaurang.Global competitiveness, customers with high demands and growing awareness has brought out a growing investment on developing quality of service. Developing of quality service is a continuous improvement process. The aim of this thesis is to measure Solna’s quality of service and customer satisfaction. The secondary aim is to measure the quality of service and give suggestions on how to take the next step in developing the quality of service at the restaurant. The suggestions are based on the written theory that consists of quality, services and the customer. My central questions in my thesis are; does Solna pass for a restaurant with good quality and if it has a high customer satisfaction rate. Probable flaws are analyzed; what is the contributor to these possible flaws and what can the restaurant do to achieve the optimal customer satisfaction? The method used in this study is of quantitative nature. The study is executed with the help of a questionnaire and the results are analyzed statistically. The questionnaire consists of 26 questions. The questions tangle areas like quality of the service, food and the staff. The results of the study are positive. The customers of the restaurant are satisfied and the quality of service is regarded as good. There are some exceptions though. The communication between the customer and staff is lacking confidence. This is an area where improvements could be made. There could be “work shop” evenings for the staff where they could come up with ideas on how to improve the service quality at the restaurant. The staff could also receive a restaurant gift certificate as an incentive

The traditional maximal lactate steady state test versus the 5× 2000 m test

Here, we compared the maximal lactate steady state velocity (vMLSS) estimated from a single-visit protocol (v5 × 2000) to the traditional multi-day protocol (vMLSS). Furthermore, we determined whether there was a lactate steady state during the time limits (Tlim) at vMLSS or v5 × 2000. Eight runners completed a half marathon (HM), the traditional protocol to determine the vMLSS and the 5 × 2000 m test in a randomised order, and a Tlim at vMLSS and at v5 × 2000 in a randomised order. The vMLSS (13.56 ± 0.90 km·h − 1 ) was higher than the v5 × 2000 (12.93 ± 0.90 km·h − 1 , p = 0.001) and comparable to the vHM (13.34 ± 0.75 km·h − 1 ). The vMLSS (r = 0.83) and the v5 × 2000 (r = 0.91) were associated with the vHM but were not indicative of the competition pace. The Tlim at vMLSS (64 ± 15 min) was lower than the Tlim at v5 × 2000 (94 ± 21 min) and the HM time (95 ± 5 min). In both Tlim, lactate was lower at 45 min than upon fi nishing the eff ort and was predictive of its duration (p < 0.05). Our results indicate that the 5 × 2000 m test can be equally useful to assess runners as the traditional MLSS protocol and that there is no lactate steady state during the Tlim at vMLSS or at v5 × 200

Multilevel convergence of interoceptive impairments in hypertension: New evidence of disrupted body-brain interactions

Interoception, the sensing of visceral body signals, involves an interplay between neural and autonomic mechanisms. Clinical studies into this domain have focused on patients with neurological and psychiatric disorders, showing that damage to relevant brain mechanisms can variously alter interoceptive functions. However, the association between peripheral cardiac-system alterations and neurocognitive markers of interoception remains poorly understood. To bridge this gap, we examined multidimensional neural markers of interoception in patients with early stage of hypertensive disease (HTD) and healthy controls. Strategically, we recruited only HTD patients without cognitive impairment (as shown by neuropsychological tests), brain atrophy (as assessed with voxel-based morphometry), or white matter abnormalities (as evidenced by diffusion tensor imaging analysis). Interoceptive domains were assessed through (a) a behavioral heartbeat detection task; (b) measures of the heart-evoked potential (HEP), an electrophysiological cortical signature of attention to cardiac signals; and (c) neuroimaging recordings (MRI and fMRI) to evaluate anatomical and functional connectivity properties of key interoceptive regions (namely, the insula and the anterior cingulate cortex). Relative to controls, patients exhibited poorer interoceptive performance and reduced HEP modulations, alongside an abnormal association between interoceptive performance and both the volume and functional connectivity of the above regions. Such results suggest that peripheral cardiac-system impairments can be associated with abnormal behavioral and neurocognitive signatures of interoception. More generally, our findings indicate that interoceptive processes entail bidirectional influences between the cardiovascular and the central nervous systems.Work has been partially supported by the CONICET, the INECO Foundation and regular projects of CONICYT/FONDECYT (1170010); FONCyT‐PICT (2012‐0412 and 2012‐1309), and FONDAP (15150012)info:eu-repo/semantics/publishedVersio

Multimodal mechanisms of human socially reinforced learning across neurodegenerative diseases

Social feedback can selectively enhance learning in diverse domains. Relevant neurocognitive mechanisms have been studied mainly in healthy persons, yielding correlational findings. Neurodegenerative lesion models, coupled with multimodal brain measures, can complement standard approaches by revealing direct multidimensional correlates of the phenomenon. To this end, we assessed socially reinforced and non-socially reinforced learning in 40 healthy participants as well as persons with behavioural variant frontotemporal dementia (n = 21), Parkinson's disease (n = 31) and Alzheimer's disease (n = 20). These conditions are typified by predominant deficits in social cognition, feedback-based learning and associative learning, respectively, although all three domains may be partly compromised in the other conditions. We combined a validated behavioural task with ongoing EEG signatures of implicit learning (medial frontal negativity) and offline MRI measures (voxel-based morphometry). In healthy participants, learning was facilitated by social feedback relative to non-social feedback. In comparison with controls, this effect was specifically impaired in behavioural variant frontotemporal dementia and Parkinson's disease, while unspecific learning deficits (across social and non-social conditions) were observed in Alzheimer's disease. EEG results showed increased medial frontal negativity in healthy controls during social feedback and learning. Such a modulation was selectively disrupted in behavioural variant frontotemporal dementia. Neuroanatomical results revealed extended temporo-parietal and fronto-limbic correlates of socially reinforced learning, with specific temporo-parietal associations in behavioural variant frontotemporal dementia and predominantly fronto-limbic regions in Alzheimer's disease. In contrast, non-socially reinforced learning was consistently linked to medial temporal/hippocampal regions. No associations with cortical volume were found in Parkinson's disease. Results are consistent with core social deficits in behavioural variant frontotemporal dementia, subtle disruptions in ongoing feedback-mechanisms and social processes in Parkinson's disease and generalized learning alterations in Alzheimer's disease. This multimodal approach highlights the impact of different neurodegenerative profiles on learning and social feedback. Our findings inform a promising theoretical and clinical agenda in the fields of social learning, socially reinforced learning and neurodegeneration.Fil: Legaz, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; Argentina. Universidad Nacional de Córdoba; ArgentinaFil: Abrevaya, Sofia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; ArgentinaFil: Dottori, Martín. Universidad de San Andrés; ArgentinaFil: Campo, Cecilia González. Universidad de San Andrés; ArgentinaFil: Birba, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; ArgentinaFil: Martorell Caro, Miguel Angel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Neurociencia Cognitiva. Fundación Favaloro. Instituto de Neurociencia Cognitiva; ArgentinaFil: Aguirre, María Julieta. Universidad Nacional de Córdoba. Instituto de Investigaciones Psicológicas. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Psicológicas; ArgentinaFil: Slachevsky, Andrea. Universidad de Chile.; ChileFil: Aranguiz, Rafael. Instituto Nacional de Geriatría; ChileFil: Serrano, Cecilia Mariela. Unidad Asistencial "Dr. César Milstein"; ArgentinaFil: Gillan, Claire M.. University of California; Estados UnidosFil: Leroi, Iracema. University of California; Estados UnidosFil: García, Adolfo Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de San Andrés; Argentina. University of California; Estados Unidos. Trinity College; Estados Unidos. Universidad Nacional de Cuyo; Argentina. Universidad de Santiago de Chile; ChileFil: Fittipaldi, Sol. Universidad de San Andrés; ArgentinaFil: Ibañez, Agustin Mariano. Universidad de San Andrés; Argentina. University of California; Estados Unidos. Trinity College; Estados Unidos. Universidad Adolfo Ibañez; Chile. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The membrane-spanning 4-domains, subfamily A (MS4A) gene cluster contains a common variant associated with Alzheimer's disease

Background\ud In order to identify novel loci associated with Alzheimer's disease (AD), we conducted a genome-wide association study (GWAS) in the Spanish population.\ud \ud Methods\ud We genotyped 1,128 individuals using the Affymetrix Nsp I 250K chip. A sample of 327 sporadic AD patients and 801 controls with unknown cognitive status from the Spanish general population were included in our initial study. To increase the power of the study, we combined our results with those of four other public GWAS datasets by applying identical quality control filters and the same imputation methods, which were then analyzed with a global meta-GWAS. A replication sample with 2,200 sporadic AD patients and 2,301 controls was genotyped to confirm our GWAS findings.\ud \ud Results\ud Meta-analysis of our data and independent replication datasets allowed us to confirm a novel genome-wide significant association of AD with the membrane-spanning 4-domains subfamily A (MS4A) gene cluster (rs1562990, P = 4.40E-11, odds ratio = 0.88, 95% confidence interval 0.85 to 0.91, n = 10,181 cases and 14,341 controls).\ud \ud Conclusions\ud Our results underscore the importance of international efforts combining GWAS datasets to isolate genetic loci for complex diseases

Enhanced Working Memory Binding by Direct Electrical Stimulation of the Parietal Cortex

Recent works evince the critical role of visual short-term memory (STM) binding deficits as a clinical and preclinical marker of Alzheimer’s disease (AD). These studies suggest a potential role of posterior brain regions in both the neurocognitive deficits of Alzheimer’s patients and STM binding in general. Thereupon, we surmised that stimulation of the posterior parietal cortex (PPC) might be a successful approach to tackle working memory deficits in this condition, especially at early stages. To date, no causal evidence exists of the role of the parietal cortex in STM binding. A unique approach to assess this issue is afforded by single-subject direct intracranial electrical stimulation of specific brain regions during a relevant cognitive task. Electrical stimulation has been used both for clinical purposes and to causally probe brain mechanisms. Previous evidence of electrical currents spreading through white matter along well defined functional circuits indicates that visual working memory mechanisms are subserved by a specific widely distributed network. Here, we stimulated the parietal cortex of a subject with intracranial electrodes as he performed the visual STM task. We compared the ensuing results to those from a non-stimulated condition and to the performance of a matched control group. In brief, direct stimulation of the parietal cortex induced a selective improvement in STM. These results, together with previous studies, provide very preliminary but promising ground to examine behavioral changes upon parietal stimulation in AD. We discuss our results regarding: (a) the usefulness of the task to target prodromal stages of AD; (b) the role of a posterior network in STM binding and in AD; and (c) the potential opportunity to improve STM binding through brain stimulation

Genome-wide association analysis of dementia and its clinical endophenotypes reveal novel loci associated with Alzheimer's disease and three causality networks : The GR@ACE project

Introduction: Large variability among Alzheimer's disease (AD) cases might impact genetic discoveries and complicate dissection of underlying biological pathways. Methods: Genome Research at Fundacio ACE (GR@ACE) is a genome-wide study of dementia and its clinical endophenotypes, defined based on AD's clinical certainty and vascular burden. We assessed the impact of known AD loci across endophenotypes to generate loci categories. We incorporated gene coexpression data and conducted pathway analysis per category. Finally, to evaluate the effect of heterogeneity in genetic studies, GR@ACE series were meta-analyzed with additional genome-wide association study data sets. Results: We classified known AD loci into three categories, which might reflect the disease clinical heterogeneity. Vascular processes were only detected as a causal mechanism in probable AD. The meta-analysis strategy revealed the ANKRD31-rs4704171 and NDUFAF6-rs10098778 and confirmed SCIMP-rs7225151 and CD33-rs3865444. Discussion: The regulation of vasculature is a prominent causal component of probable AD. GR@ACE meta-analysis revealed novel AD genetic signals, strongly driven by the presence of clinical heterogeneity in the AD series