406 research outputs found
Intestinal microbiome in normal ageing, frailty and cognition decline
No full textPurpose of review: The intestinal microbiome modulates the risk of several age-related chronic diseases and syndromes, including frailty and neurodegenerative diseases. Herein we provided an update on the influence of gut microbiota on physical and cognitive performance in older age and suggest microbiota-targeted interventions for healthy ageing.
Recent findings: Low uniqueness index of the gut microbiome and high representation of Bacteroides are independently associated with mortality in older individuals, while the centenarian microbiome is characterized by high abundance of Lactobacilli and Bifidobacteria. Frailty syndrome, sarcopenia and cognitive decline are associated with reduced faecal microbiota biodiversity, reduced abundance of bacteria able to synthetize short-chain fatty acids (SCFA), including Faecalibacterium prausnitzii, and reduced faecal butyrate levels. Dietary intervention, especially involving Mediterranean diet, and exercise training seem to be associated with improved biodiversity of the microbiota, increased capacity of SCFA synthesis and, probably, protection against the onset of frailty and cognitive decline.
Summary: The gut microbiota biodiversity and composition may reflect the different ageing trajectory, but further research is needed to understand potential independent and combined effects of environmental and lifestyle factors in older adults, especially from a clinical point of view
Author comment on RC4: 'Review of Strasser et al.: Rofental catchment', Adam Winstral, 02 Oct 2017
No full textJohnson Hall
No full textJohnson Hall basement residents: Janaree Ediger, Sharon Pavlish, Jean Sterritt, Liz Hageman, Martha Strasser, Henriette Mantel, Andrea Babcock, Pat Neneman
The New Paternalism
No full textThe author argues that the belief that patient autonomy has great
moral value has justified a new form of medical paternalism which can have
effects similar to those of the old rejected form. He cites the argument that
"all illness represents a state of diminished autonomy" and that therefore
autonomy is not overridden when physicians make all decisions. Another view
is that, in some situations, withholding information may prevent patient
deterioration and loss of autonomy. Abridgement of present autonomy, then, is
permissible if it promotes future autonomy. Strasser also rejects physician
decision making based on patients' previously communicated values or on the
theory that patient values are important but not decisive. He concludes that
if we "allow paternalistic practices, then we should admit that we are denying
autonomy in light of some other good rather than claim that, somehow, we are
respecting autonomy by abridging it." (KIE abstract
Mass-transport processes and sedimentary mélanges: internal deformation, stratal disruption and occurrence of exotic blocks
No full textDetailed studies in recent years of mélanges and chaotic deposits in various mountain ranges around the world have resulted in the recognition of a large number of sedimentary mélanges. These sedimentary mélanges mostly originated from sedimentary mass-transport processes and flows, although they were strongly deformed by post-depositional, tectonic and mud-diapiric events. Therefore, they commonly represent excellent fossil examples of mass-transport deposits (MTDs) to investigate the processes involved in their origin. Large scale, basin-wide fossil MTDs, including sedimentary mélanges, are complex units involving the entire spectra of mass-transport processes. Their down-slope movement is facilitated by: 1) shear-dominated viscous flows within a muddy matrix, 2) mud-silt-sandy matrix sustained by fluid overpressure, 3) mm-thick shear zones with advection of grains/fluids. These three types of MTDs display different potential of stratal disruption depending on the sediment strength (composition and compaction), the activity of fluid (over)pressure, the length of en-mass transport and the rheology of the MTD-substratum interface. The potential of mixing of rocks of different ages and metamorphic degrees, and of diverse structural units and paleogeographic domains is conditioned by: 1) the geometry and evolution of slope failure, 2) the depth of the headwall surface, 3) the geometry and tectonic setting of sedimentary basins and basin margins, 4) the effectiveness of tectonic structures and serpentinite diapirs in exposing/exhuming deep-seated HP rocks.
We discuss here the potential of mass-transport processes in mélange formation, based on both on-land and seafloor examples and on their distribution and volumetric relevance in the sedimentary record of accretionary wedges
A complementary role for ELF3 and TFL1 in the regulation of flowering time by ambient temperature.
No full textPlants regulate their time to flowering by gathering information from the environment. Photoperiod and temperature are among the most important environmental variables. Sub-optimal, but not near-freezing, temperatures regulate flowering through the thermosensory pathway, which overlaps with the autonomous pathway. Here we show that ambient temperature regulates flowering by two genetically distinguishable pathways, one requiring TFL1 and another requiring ELF3. The delay in flowering time observed at lower temperatures was partially suppressed in single elf3 and tfl1 mutants, whereas double elf3 tfl1 mutants were insensitive to temperature. tfl1 mutations abolished the temperature response in cryptochrome mutants that are deficient in photoperiod perception, but not in phyB mutants, which have a constitutive photoperiodic response. In contrast to tfl1, elf3 mutations were able to suppress the temperature response in phyB mutants, but not in cryptochrome mutants. Gene expression profiles revealed that the tfl1 and elf3 effects are due to the activation of different sets of genes, and identified CCA1 and SOC1/AGL20 as being important cross-talk points. Finally, genome-wide gene expression analysis strongly suggests a general and complementary role for ELF3 and TFL1 in temperature signalling.Fil: Strasser, Bárbara. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Alvarez, Mariano J.. Columbia University; Estados UnidosFil: Califano, Andrea. Columbia University; Estados UnidosFil: Cerdan, Pablo Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin
Message from the Organizers
No full textGreen Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Electrical Power Grid
The covariance structure of conditional maximum likelihood estimates
No full textIn this paper we consider conditional maximum likelihood (cml) estimates for
item parameters in the Rasch model under random subject parameters. We give
a simple approximation for the asymptotic covariance matrix of the cml-estimates.
The approximation is stated as a limit theorem when the number of item parameters
goes to infinity. The results contain precise mathematical information on the order
of approximation.
The results enable the analysis of the covariance structure of cml-estimates when
the number of items is large. Let us give a rough picture. The covariance matrix has
a dominating main diagonal containing the asymptotic variances of the estimators.
These variances are almost equal to the efficient variances under ml-estimation when
the distribution of the subject parameter is known. Apart from very small numbers
n of item parameters the variances are almost not affected by the number n. The
covariances are more or less negligible when the number of item parameters is large.
Although this picture intuitively is not surprising it has to be established in precise
mathematical terms. This has been done in the present paper.
The paper is based on previous results [5] of the author concerning conditional
distributions of non-identical replications of Bernoulli trials. The mathematical background
are Edgeworth expansions for the central limit theorem. These previous results
are the basis of approximations for the Fisher information matrices of cmlestimates.
The main results of the present paper are concerned with the approximation
of the covariance matrices.
Numerical illustrations of the results and numerical experiments based on the
results are presented in Strasser, [6]. (author's abstract
- …
