1,064 research outputs found
The Structure on Invariant Measures of generic diffeomorphisms
Let be an isolated non-trival transitive set of a generic
diffeomorphism f\in\Diff(M). We show that the space of invariant measures
supported on coincides with the space of accumulation measures of
time averages on one orbit. Moreover, the set of points having this property is
residual in (which implies the set of irregular points is also
residual in ). As an application, we show that the non-uniform
hyperbolicity of irregular points in with totally 0 measure
(resp., the non-uniform hyperbolicity of a generic subset in )
determines the uniform hyperbolicity of
The microbiological profile and presence of bloodstream infection influence mortality rates in necrotizing fasciitis
Sampling Neural Radiance Fields for Refractive Objects
Recently, differentiable volume rendering in neural radiance fields (NeRF)
has gained a lot of popularity, and its variants have attained many impressive
results. However, existing methods usually assume the scene is a homogeneous
volume so that a ray is cast along the straight path. In this work, the scene
is instead a heterogeneous volume with a piecewise-constant refractive index,
where the path will be curved if it intersects the different refractive
indices. For novel view synthesis of refractive objects, our NeRF-based
framework aims to optimize the radiance fields of bounded volume and boundary
from multi-view posed images with refractive object silhouettes. To tackle this
challenging problem, the refractive index of a scene is reconstructed from
silhouettes. Given the refractive index, we extend the stratified and
hierarchical sampling techniques in NeRF to allow drawing samples along a
curved path tracked by the Eikonal equation. The results indicate that our
framework outperforms the state-of-the-art method both quantitatively and
qualitatively, demonstrating better performance on the perceptual similarity
metric and an apparent improvement in the rendering quality on several
synthetic and real scenes.Comment: SIGGRAPH Asia 2022 Technical Communications. 4 pages, 4 figures, 1
table. Project: https://alexkeroro86.github.io/SampleNeRFRO/ Code:
https://github.com/alexkeroro86/SampleNeRFR
Diffuse tensor cardiac MRI evaluation of fiber architecture of athlete hypertrophic heart in vivo
âI canât see an end in sight.â How the COVID-19 pandemic may influence suicide risk: a qualitative study
<jats:p> Zusammenfassung: Theoretischer Hintergrund: Das Ziel der vorliegenden Studie war es, eine deutschsprachige Adaptation der Bergen Study Addiction Scale (BStAS), einer Skala zur Erfassung von exzessivem Studierverhalten, zu entwickeln und zu validieren. Methode: Die Daten von 615 Studierenden wurden analysiert. Die DimensionalitĂ€t der BStAS wurde mittels konfirmatorischer Faktorenanalyse ĂŒberprĂŒft. AuĂerdem wurden Korrelations- und hierarchische Regressionsanalysen durchgefĂŒhrt, um ZusammenhĂ€nge von exzessivem Studierverhalten mit Persönlichkeit und Gesundheit zu untersuchen. Ergebnisse: Der Vergleich mit Dynamic Fit Index Cutoffs deutete auf eine moderate Missspezifikation des einfaktoriellen Modells hin. Wie erwartet war exzessives Studierverhalten positiv mit wöchentlichen Lernstunden, Neurotizismus, wahrgenommenem Stress, psychosomatischen Beschwerden und Schlafproblemen assoziiert und hing negativ mit Lebenszufriedenheit zusammen. Schlussfolgerung: Es ist fraglich, ob alle Items der BStAS Aspekte einer Verhaltenssucht erfassen. Die Ergebnisse legen dennoch nahe, dass die BStAS ein Studierverhalten misst, das in Bezug auf physische und psychische Gesundheit von Relevanz ist. </jats:p>
Enhanced Thermoelectric Power in Dual-Gated Bilayer Graphene
Thermoelectric power of a material, typically governed by its band structure
and carrier density, can be varied by chemical doping that is often restricted
by solubility of the dopant. Materials showing large thermoelectric power are
useful for many industrial applications, such as the heat-to-electricity
conversion and the thermoelectric cooling device. Here we show a full electric
field tuning of thermoelectric power in a dual-gated bilayer graphene device
resulting from the opening of a band-gap by applying a perpendicular electric
field on bilayer graphene. We uncover a large enhancement in thermoelectric
power at low temperature, which may open up a new possibility in low
temperature thermoelectric application using graphene-based device.Comment: 12 pages, 4 figure
Early utilization of hypertonic peritoneal dialysate and subsequent risks of non-traumatic amputation among peritoneal dialysis patients: a nationwide retrospective longitudinal study
BACKGROUND: The hemodialysis (HD) population has a particularly high incidence of amputation, which is likely associated with decreased tissue oxygenation during HD. However, information about the risk factors leading to amputation in peritoneal dialysis (PD) patients is limited. Here, we have investigated the association between the use of hypertonic peritoneal dialysate (HPD) and subsequent amputation in PD patients. METHODS: Based on the data from the Taiwan National Health Insurance research database, this observational cohort study enrolled 203 PD patients who had received HPD early during treatment and had not undergone amputation and 296 PD controls who had not undergone amputation. Subjects were followed through until the end of 2009 and the event rates of new non-traumatic amputation were compared between groups. RESULTS: The incidence of amputation was 3 times higher for the HPD cohort than for the comparison cohort (23.68 vs. 8.01 per 1000 person-years). The hazard ratio (HR) for this group, estimated using a multivariable Cox model, was 2.48 (95% confidence interval [CI] = 1.06â5.79). The HR for patients with both diabetes and early adoption of HPD increased to 44.34 (95% CI = 5.51-357.03), compared to non-HPD non-diabetic PD controls. CONCLUSION: Early utilization of HPD in PD patients is associated with increasing risk of amputation; this risk considerably increases for those with concomitant diabetes
Diagnostic efficacy of the triglycerideâglucose index in the prediction of contrast-induced nephropathy following percutaneous coronary intervention
IntroductionContrast-induced nephropathy (CIN) is a common complication of percutaneous coronary intervention (PCI). Identifying patients at high CIN risk remains challenging. The triglyceride-glucose (TyG) index may help predict CIN but evidence is limited. We conducted a meta-analysis to evaluate the diagnostic value of TyG index for CIN after PCI.MethodsA systematic literature search was performed in MEDLINE, Cochrane, and EMBASE until August 2023 (PROSPERO registration: CRD42023452257). Observational studies examining TyG index for predicting CIN risk in PCI patients were included. This diagnostic meta-analysis aimed to evaluate the accuracy of the TyG index in predicting the likelihood of CIN. Secondary outcomes aimed to assess the pooled incidence of CIN and the association between an elevated TyG index and the risk of CIN.ResultsFive studies (Turkey, n=2; China, n=3) with 3518 patients (age range: 57.6 to 68.22 years) were included. The pooled incidence of CIN was 15.3% [95% confidence interval (CI) 11-20.8%]. A high TyG index associated with increased CIN risk (odds ratio: 2.25, 95% CI 1.82-2.77). Pooled sensitivity and specificity were 0.77 (95% CI 0.59-0.88) and 0.55 (95% CI 0.43-0.68) respectively. Analysis of the summary receiver operating characteristic (sROC) curve revealed an area under the curve of 0.69 (95% CI 0.65-0.73). There was a low risk of publication bias (p = 0.81).ConclusionThe TyG index displayed a noteworthy correlation with the risk of CIN subsequent to PCI. However, its overall diagnostic accuracy was found to be moderate in nature. While promising, the TyG index should not be used in isolation for CIN screening given the heterogeneity between studies. In addition, the findings cannot be considered conclusive given the scarcity of data. Further large-scale studies are warranted to validate TyG cutoffs and determine how to optimally incorporate it into current risk prediction models.Systematic Review Registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023452257, identifier CRD42023452257
- âŠ