128 research outputs found
Stochastic resonance between dissipative structures in a bistable noise-sustained dynamics
We study an extended system that without noise shows a monostable dynamics,
but when submitted to an adequate multiplicative noise, an effective bistable
dynamics arise. The stochastic resonance between the attractors of the
\textit{noise-sustained dynamics} is investigated theoretically in terms of a
two-state approximation. The knowledge of the exact nonequilibrium potential
allows us to obtain the output signal-to-noise ratio. Its maximum is predicted
in the symmetric case for which both attractors have the same nonequilibrium
potential value.Comment: RevTex, 13 pages, 6 figures, accepted in Physical Review
Transitie van een psychogeriatrische dagbehandeling in het verpleeghuis naar een laagdrempelige dagbehandeling in de wijk: een pilotonderzoek
Achtergrond
In deze studie wordt de transitie van een reguliere psychogeriatrische dagbehandeling in het verpleeghuis naar
laagdrempelige psychogeriatrische dagbehandeling met mantelzorgondersteuning (LPD-plus MO) in de wijk op de voet
gevolgd. Het bewezen effectieve Model Ontmoetingscentra vormde het uitgangspunt bij de transitie.
Methode
Door middel van kwalitatieve analyse van documenten en interviews met sleutelfiguren (n = 11) worden factoren opgespoord
die de overgang van de oude naar de nieuwe vorm van dagbehandeling bevorderen of belemmeren. Bij deelnemers en
mantelzorgers die langer dan 6 maanden gebruik maken van het ondersteuningsaanbod wordt de tevredenheid over het
nieuwe aanbod gepeild.
Resultaten
Verschillende kenmerken van LPD-plus MO blijken de samenwerking met andere zorg- en welzijnsaanbieders in de regio te
bevorderen, zoals: de laagdrempelige locatie, de sociale integratie in de buurt en de focus op gecombineerde ondersteuning
van zowel de persoon met dementie als de mantelzorger. Een goede samenwerking met andere zorg- en welzijnsorganisaties,
en een geschikte locatie vergemakkelijken de implementatie. De aanwezigheid van concurrerend aanbod in de regio, zoals
ontmoetingscentra voor mensen met dementie en hun mantelzorgers, belemmeren de werving van deelnemers voor de LPDplus
MO. Deelnemers en mantelzorgers zijn over het algemeen tevreden over het ondersteuningsprogramma.
Conclusie en discussie
De transitie is succesvol verlopen en levert andere reguliere dagbehandelingen tips op voor de transitie naar LPD-plus MO
Limit cycle induced by multiplicative noise in a system of coupled Brownian motors
We study a model consisting of nonlinear oscillators with {\em global
periodic} coupling and {\em local multiplicative} and additive noises. The
model was shown to undergo a nonequilibrium phase transition towards a
broken-symmetry phase exhibiting noise-induced "ratchet" behavior. A previous
study \cite{[7]} focused on the relationship between the character of
thehysteresis loop, the number of ``homogeneous'' mean-field solutions and the
shape of the stationary mean-field probability distribution function. Here we
show --as suggested by the absence of stable solutions when the load force is
beyond a critical value-- the existence of a limit cycle induced by
both:multiplicative noise and {\em global periodic} coupling.Comment: Submitted to Phys. Rev. E, RevTex, 18 pgs, 5 figure
Genetic factors and insulin secretion: gene variants in the IGF genes
IGFs are important regulators of pancreatic beta-cell development, growth, and maintenance. Mutations in the IGF genes have been found to be associated with type 2 diabetes, myocardial infarction, birth weight, and obesity. These associations could result from changes in insulin secretion. We have analyzed glucose-stimulated insulin secretion using hyperglycemic clamps in carriers of a CA repeat in the IGF-I promoter and an ApaI polymorphism in the IGF-II gene. Normal and impaired glucose-tolerant subjects (n = 237) were independently recruited from three different populations in the Netherlands and Germany to allow independent replication of associations. Both first- and second-phase insulin secretion were not significantly different between the various IGF-I or IGF-II genotypes. Remarkably, noncarriers of the IGF-I CA repeat allele had both a reduced insulin sensitivity index (ISI) and disposition index (DI), suggesting an altered balance between insulin secretion and insulin action. Other diabetes-related parameters were not significantly different for both the IGF-I and IGF-II gene variant. We conclude that gene variants in the IGF-I and IGF-II genes are not associated with detectable variations in glucose-stimulated insulin secretion in these three independent populations. Further studies are needed to examine the exact contributions of the IGF-I CA repeat alleles to variations in ISI and DI
Twitteren over grondrechten in tijden van de pandemie: Startpunt voor discussie of stok om mee te slaan?
The Legitimacy and Effectiveness of Law & Governance in a World of Multilevel Jurisdiction
From Pre-Diabetes to Type 2 Diabetes in Obese Youth: Pathophysiological characteristics along the spectrum of glucose dysregulation
Impaired glucagon-like peptide-1-induced insulin secretion in carriers of transcription factor 7-like 2 (TCF7L2) gene polymorphisms
Combined Risk Allele Score of Eight Type 2 Diabetes Genes Is Associated With Reduced First-Phase Glucose-Stimulated Insulin Secretion During Hyperglycemic Clamps
OBJECTIVE - At least 20 type 2 diabetes loci have now been identified, and several of these are associated with altered β-cell function. In this study, we have investigated the combined effects of eight known β-cell loci on insulin secretion stimulated by three different secretagogues during hyperglycemic clamps. RESEARCH DESIGN AND METHODS - A total of 447 subjects originating from four independent studies in the Netherlands and Germany (256 with normal glucose tolerance [NGT]/ 191 with impaired glucose tolerance [IGT]) underwent a hyperglycemic clamp. A subset had an extended clamp with additional glucagon-like peptide (GLP)-1 and arginine (n = 224). We next genotyped single nucleotide polymorphisms in TCF7L2, KCNJ11, CDKAL1, IGF2BP2, HHEX/IDE, CDKN2A/B, SLC30A8, and MTNR1B and calculated a risk allele score by risk allele counting. RESULTS - The risk allele score was associated with lower first-phase glucose-stimulated insulin secretion (GSIS) (P = 7.1 × 1
Serum Biomarker Profile Including CCL1, CXCL10, VEGF, and Adenosine Deaminase Activity Distinguishes Active From Remotely Acquired Latent Tuberculosis
INTRODUCTION: There is an urgent medical need to differentiate active tuberculosis (ATB) from latent tuberculosis infection (LTBI) and prevent undertreatment and overtreatment. The aim of this study was to identify biomarker profiles that may support the differentiation between ATB and LTBI and to validate these signatures. MATERIALS AND METHODS: The discovery cohort included adult individuals classified in four groups: ATB (n = 20), LTBI without prophylaxis (untreated LTBI; n = 20), LTBI after completion of prophylaxis (treated LTBI; n = 20), and healthy controls (HC; n = 20). Their sera were analyzed for 40 cytokines/chemokines and activity of adenosine deaminase (ADA) isozymes. A prediction model was designed to differentiate ATB from untreated LTBI using sparse partial least squares (sPLS) and logistic regression analyses. Serum samples of two independent cohorts (national and international) were used for validation. RESULTS: sPLS regression analyses identified C-C motif chemokine ligand 1 (CCL1), C-reactive protein (CRP), C-X-C motif chemokine ligand 10 (CXCL10), and vascular endothelial growth factor (VEGF) as the most discriminating biomarkers. These markers and ADA(2) activity were significantly increased in ATB compared to untreated LTBI (p ≤ 0.007). Combining CCL1, CXCL10, VEGF, and ADA2 activity yielded a sensitivity and specificity of 95% and 90%, respectively, in differentiating ATB from untreated LTBI. These findings were confirmed in the validation cohort including remotely acquired untreated LTBI participants. CONCLUSION: The biomarker signature of CCL1, CXCL10, VEGF, and ADA2 activity provides a promising tool for differentiating patients with ATB from non-treated LTBI individuals
Coexpression of vesicular glutamate transporters 1 and 2, glutamic acid decarboxylase and calretinin in rat entorhinal cortex
We studied the distribution and coexpression of vesicular glutamate transporters (VGluT1, VGluT2), glutamic acid decarboxylase
(GAD) and calretinin (CR, calcium-binding protein) in rat entorhinal cortex, using immunofluorescence staining and multichannel
confocal laser scanning microscopy. Images were computer processed and subjected to automated 3D object recognition, colocalization
analysis and 3D reconstruction. Since the VGluTs (in contrast to CR and GAD) occurred in fibers and axon terminals only, we
focused our attention on these neuronal processes. An intense, punctate VGluT1-staining occurred everywhere in the entorhinal
cortex. Our computer program resolved these punctae as small 3D objects. Also VGluT2 showed a punctate immunostaining pattern,
yet with half the number of 3D objects per tissue volume compared with VGluT1, and with statistically significantly larger
3D objects. Both VGluTs were distributed homogeneously across cortical layers, with in MEA VGluT1 slightly more densely distributed
than in LEA. The distribution pattern and the size distribution of GAD 3D objects resembled that of VGluT2. CR-immunopositive
fibers were abundant in all cortical layers. In double-stained sections we noted ample colocalization of CR and VGluT2, whereas
coexpression of CR and VGluT1 was nearly absent. Also in triple-staining experiments (VGluT2, GAD and CR combined) we noted
coexpression of VGluT2 and CR and, in addition, frequent coexpression of GAD and CR. Modest colocalization occurred of VGluT2
and GAD, and incidental colocalization of all three markers. We conclude that the CR-containing axon terminals in the entorhinal
cortex belong to at least two subpopulations of CR-neurons: a glutamatergic excitatory and a GABAergic inhibitory
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