256 research outputs found
Executive Functions in Chronic Mesial Temporal Lobe Epilepsy
There is no consensus as to whether mesial temporal lobe epilepsy (MTLE) leads to executive function deficits. In this study, we adopted an extensive neuropsychological test battery and assessed different executive functions in chronic, unilateral MTLE. Performance of MTLE patients was compared with that of healthy peers and with normative data. Several MTLE patients had scores below cut-off or below the 10th percentile of normative data. Scores of the whole patient group were overall in the average range of normative data. Relative to controls, MTLE patients performed poorly in tests of working memory, cognitive flexibility, categorical verbal fluency, set-shifting, categorization, and planning. These findings raise an important methodological issue as they suggest that executive function deficits in chronic MTLE may be individually variable and that their assessment should include different tests. Deficits in chronic MTLE are not limited to temporal lobe functions, such as memory, but may extend to extra temporal cognitive domains, such as executive functions
Towards Scalable Real-time Analytics:: An Architecture for Scale-out of OLxP Workloads
We present an overview of our work on the SAP HANA Scale-out Extension, a novel distributed database architecture designed to support large scale analytics over real-time data. This platform permits high performance OLAP with massive scale-out capabilities, while concurrently allowing OLTP workloads. This dual capability enables analytics over real-time changing data and allows fine grained user-specified service level agreements (SLAs) on data freshness. We advocate the decoupling of core database components such as query processing, concurrency control, and persistence, a design choice made possible by advances in high-throughput low-latency networks and storage devices. We provide full ACID guarantees and build on a logical timestamp mechanism to provide MVCC-based snapshot isolation, while not requiring synchronous updates of replicas. Instead, we use asynchronous update propagation guaranteeing consistency with timestamp validation. We provide a view into the design and development of a large scale data management platform for real-time analytics, driven by the needs of modern enterprise customers
Soft Supersymmetry Breaking in Calabi-Yau Orientifolds with D-branes and Fluxes
In this paper we compute the N=1 effective low energy action for a stack of N
space-time filling D3-branes in generic type IIB Calabi-Yau orientifolds with
non-trivial background fluxes by reducing the Dirac-Born-Infeld and
Chern-Simons actions. Specifically, we determine the Kahler potential for the
excitations of the D-brane including their couplings to all bulk moduli fields.
In the effective theory, N=1 supergravity is spontaneously broken by the
presence of fluxes and we compute the induced soft supersymmetry breaking
terms. We find an interesting structure in the resulting soft terms with
generically universal soft scalar masses.Comment: LaTeX, 41 pages, minor corrections and references adde
The effective action of N=1 Calabi-Yau orientifolds
We determine the N=1 low energy effective action for compactifications of
type IIB string theory on compact Calabi-Yau orientifolds in the presence of
background fluxes from a Kaluza-Klein reduction. The analysis is performed for
Calabi-Yau threefolds which admit an isometric and holomorphic involution. We
explicitly compute the Kahler potential, the superpotential and the gauge
kinetic functions and check the consistency with N=1 supergravity. We find a
new class of no-scale Kahler potentials and show that their structure can be
best understood in terms of a dual formulation where some of the chiral
multiplets are replaced by linear multiplets. For O3- and O7-planes the scalar
potential is expressed in terms of a superpotential while for O5- and O9-planes
also a D-term and a massive linear multiplet can be present. The relation with
the associated F-theory compactifications is briefly discussed.Comment: 40 pages, typos corrected, discussion of no-scale property improve
The Kahler Cone as Cosmic Censor
M-theory effects prevent five-dimensional domain-wall and black-hole
solutions from developing curvature singularities. While so far this analysis
was performed for particular models, we now present a model-independent proof
that these solutions do not have naked singularities as long as the Kahler
moduli take values inside the extended Kahler cone. As a by-product we obtain
information on the regularity of the Kahler-cone metric at boundaries of the
Kahler cone and derive relations between the geometry of moduli space and
space-time.Comment: 21 pages, 1 figure. Improved discussion of the relation between
Kahler moduli and five-dimensional scalars. No changes in the conclusion
The effective action of Type IIA Calabi-Yau orientifolds
The N=1 effective action for generic type IIA Calabi-Yau orientifolds in the
presence of background fluxes is computed from a Kaluza-Klein reduction. The
Kahler potential, the gauge kinetic functions and the flux-induced
superpotential are determined in terms of geometrical data of the Calabi-Yau
orientifold and the background fluxes. The moduli space is found to be a Kahler
subspace of the N=2 moduli space and shown to coincide with the moduli space
arising in compactification of M-theory on a specific class of G_2 manifolds.
The superpotential depends on all geometrical moduli and vanishes at leading
order when background fluxes are turned off. The N=1 chiral coordinates
linearize the appropriate instanton actions such that instanton effects can
lead to holomorphic corrections of the superpotential. Mirror symmetry between
type IIA and type IIB orientifolds is shown to hold at the level of the
effective action in the large volume - large complex structure limit.Comment: 51 pages, typos correcte
Cancer Incidence of 2,4-D Production Workers
Despite showing no evidence of carcinogenicity in laboratory animals, the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) has been associated with non-Hodgkin lymphoma (NHL) in some human epidemiology studies, albeit inconsistently. We matched an existing cohort of 2,4-D manufacturing employees with cancer registries in three US states resulting in 244 cancers compared to 276 expected cases. The Standardized Incidence Ratio (SIR) for the 14 NHL cases was 1.36 (95% Confidence Interval (CI) 0.74–2.29). Risk estimates were higher in the upper cumulative exposure and duration subgroups, yet not statistically significant. There were no clear patterns of NHL risk with period of hire and histology subtypes. Statistically significant results were observed for prostate cancer (SIR = 0.74, 95% CI 0.57–0.94), and “other respiratory” cancers (SIR = 3.79, 95% CI 1.22–8.84; 4 of 5 cases were mesotheliomas). Overall, we observed fewer cancer cases than expected, and a non statistically significant increase in the number of NHL cases
Genetic regulation of pituitary gland development in human and mouse
Normal hypothalamopituitary development is closely related to that of the forebrain and is dependent upon a complex genetic cascade of transcription factors and signaling molecules that may be either intrinsic or extrinsic to the developing Rathke’s pouch. These factors dictate organ commitment, cell differentiation, and cell proliferation within the anterior pituitary. Abnormalities in these processes are associated with congenital hypopituitarism, a spectrum of disorders that includes syndromic disorders such as septo-optic dysplasia, combined pituitary hormone deficiencies, and isolated hormone deficiencies, of which the commonest is GH deficiency. The highly variable clinical phenotypes can now in part be explained due to research performed over the last 20 yr, based mainly on naturally occurring and transgenic animal models. Mutations in genes encoding both signaling molecules and transcription factors have been implicated in the etiology of hypopituitarism, with or without other syndromic features, in mice and humans. To date, mutations in known genes account for a small proportion of cases of hypopituitarism in humans. However, these mutations have led to a greater understanding of the genetic interactions that lead to normal pituitary development. This review attempts to describe the complexity of pituitary development in the rodent, with particular emphasis on those factors that, when mutated, are associated with hypopituitarism in humans
Monitoring changes of paramagnetically-shifted 31P signals in phospholipid vesicles
Phospholipid vesicles are commonly used as biomimetics in the investigation of the interaction of various species with cell membranes. In this paper we present a 31P NMR investigation of a simple vesicle system using a paramagnetic shift reagent to probe the inner and outer layers of the lipid bilayer. Time-dependent changes in the 31P NMR signal are observed, which differ whether the paramagnetic species is inside or outside the vesicle, and on the choice of buffer solution used. An interpretation of these results is given in terms of the interaction of the paramagnetic shift reagent with the lipids
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