165 research outputs found
Sticky Flavors
The Fr\'echet mean, a generalization to a metric space of the expectation of
a random variable in a vector space, can exhibit unexpected behavior for a wide
class of random variables. For instance, it can stick to a point (more
generally to a closed set) under resampling: sample stickiness. It can stick to
a point for topologically nearby distributions: topological stickiness, such as
total variation or Wasserstein stickiness. It can stick to a point for slight
but arbitrary perturbations: perturbation stickiness. Here, we explore these
and various other flavors of stickiness and their relationship in varying
scenarios, for instance on CAT() spaces, .
Interestingly, modulation stickiness (faster asymptotic rate than )
and directional stickiness (a generalization of moment stickiness from the
literature) allow for the development of new statistical methods building on an
asymptotic fluctuation, where, due to stickiness, the mean itself features no
asymptotic fluctuation. Also, we rule out sticky flavors on manifolds in
scenarios with curvature bounds
An improved head-space analysis method for methane in seawater
A widely used degassing method for methane in seawater employing vacuum was tested and subsequently improved. It yielded 62 ± 3.8% of the total dissolved methane, hence a reproducible correction factor was established. The method was then applied to measure CH4 in the sea-air boundary layer and simultaneously in the overlying air along two transects in the eastern Equatorial Pacific off Peru in March of 1992. The results showed surprising small-scale reversals of the methane exchange between ocean and atmosphere in this region. Generally the ocean acted as a source of methane but also methane uptake by the ocean was found. This was mainly a consequence of high CH4 concentrations in the air which deviated considerably from the long-term and large-scale average. If applied to the flux rate calculations, the observed variabilities indicate that both rate and direction of the methane flux through the air-sea interface vary considerably depending on the atmospheric CH4 content. The implications are that even ocean areas with high concentrations of dissolved CH4 can be considerably weaker sources than would be expected on the basis of 1.7 ppmv mean atmospheric methane content. Based on improved simultaneous analyses of both air and water samples, the ocean-atmosphere flux of methane would therefore be more dynamic than previously thought
Types of Stickiness in BHV Phylogenetic Tree Spaces and Their Degree
It has been observed that the sample mean of certain probability
distributions in Billera-Holmes-Vogtmann (BHV) phylogenetic spaces is confined
to a lower-dimensional subspace for large enough sample size. This non-standard
behavior has been called stickiness and poses difficulties in statistical
applications when comparing samples of sticky distributions. We extend previous
results on stickiness to show the equivalence of this sampling behavior to
topological conditions in the special case of BHV spaces. Furthermore, we
propose to alleviate statistical comparision of sticky distributions by
including the directional derivatives of the Fr\'echet function: the degree of
stickiness.Comment: 8 Pages, 1 Figure, conference submission to GSI 202
Fluidaustritte an kollidierenden Plattengrenzen
Plate collision cuases expulsion of fluids and gases and material turnover in the deep ocean along the global subduction zones. Such cold vents are characterized by mineral precipitates and characteristic assemblages of macro organisms. The latter harbor symbiotic bacteria which utilize the chemically-reduced constituents (CH4 and H2S) of the expelled fluids as their energy and supply their host with food. The interaction between tectonically-induced fluid flow and pumping activity of the vent fauna sets up a shallow recirculation system whose magnitude can be estimated from direct measurements by an in situ vent sampling device (VESP) in connection with tracer studies. The dewatering rates based on the biogeochemical estimates agree surprisingly well with those derived from geophysical estimates
Fluid venting in the eastern Aleutian subduction zone
Fluid venting has been observed along 800 km of the Alaska convergent margin. The fluid venting sites are located near the deformation front, are controlled by subsurface structures, and exhibit the characteristics of cold seeps seen in other convergent margins. The more important characteristics include (1) methane plumes in the lower water column with maxima above the seafloor which are traceable to the initial deformation ridges; (2) prolific colonies of vent biota aligned and distributed in patches controlled by fault scarps, overâsteepened folds or outcrops of bedding planes; (3) calcium carbonate and barite precipitates at the surface and subsurface of vents; and (4) carbon isotope evidence from tissue and skeletal hard parts of biota, as well as from carbonate precipitates, that vents expel either methaneâ or sulfideâdominated fluids. A biogeochemical approach toward estimating fluid flow rates from individual vents based on oxygen flux measurements and vent fluid analysis indicates a mean value of 5.5±0.7 L mâ2 dâ1 for tectonicsâinduced water flow [Wallmann et al., 1997b]. A geophysical estimate of dewatering from the same area [von Huene et al., 1997] based on sediment porosity reduction shows a fluid loss of 0.02 L mâ2 dâ1 for a 5.5 km wide converged segment near the deformation front. Our videoâguided surveys have documented vent biota across a minimum of 0.1% of the area of the convergent segment off Kodiak Island; hence an average rate of 0.006 L mâ2 dâ1 is estimated from the biogeochemical approach. The two estimates for tectonicsâinduced water flow from the accretionary prism are in surprisingly good agreement
Formin follows function: a muscle-specific isoform of FHOD3 is regulated by CK2 phosphorylation and promotes myofibril maintenance
Phosphorylation of the muscle-specific formin splice variant FHOD3 by CK2 regulates its stability, myofibril targeting, and myofibril integrity
Power increases the self-serving bias in the attribution of collective successes and failures
Three studies test the effect of power on the self?serving bias in attributing collective outcomes. The first two studies measure (Experiment 1) and manipulate (Experiment 2) power and then measure the internal (vs. external) attribution of past successes and failures. Consistently, those who feel powerful show a stronger self?serving tendency to selectively attribute successes internally and failures externally than those who feel powerless. Experiment 3 compares the effects of power (control over others) and personal control (over oneself). We find that power increases the self?serving bias, but a lack of control can limit this effect by reducing the external attribution of failures. Presumably, people who lack control are disinclined to attribute outcomesâincluding failuresâexternally because doing so would further aggravate their lack of control. Together, these results suggest that power increases a bias in the attribution of success and failure and thus presents a fundamental challenge to good leadership
Pulmonary Hypertension in Adults with Congenital Heart Disease: Real-World Data from the International COMPERA-CHD Registry
Introduction: Pulmonary hypertension (PH) is a common complication in patients with
congenital heart disease (CHD), aggravating the natural, post-operative, or post-interventional course
of the underlying anomaly. The various CHDs differ substantially in characteristics, functionality, and
clinical outcomes among each other and compared with other diseases with pulmonary hypertension.
Objective: To describe current management strategies and outcomes for adults with PH in relation to
different types of CHD based on real-world data. Methods and results: COMPERA (Comparative,
Prospective Registry of Newly Initiated Therapies for Pulmonary Hypertension) is a prospective,
international PH registry comprising, at the time of data analysis, >8200 patients with various forms of
PH. Here, we analyzed a subgroup of 680 patients with PH due to CHD, who were included between
2007 and 2018 in 49 specialized centers for PH and/or CHD located in 11 European countries. At
enrollment, the patientsâ median age was 44 years (67% female), and patients had either pre-tricuspid
shunts, post-tricuspid shunts, complex CHD, congenital left heart or aortic disease, or miscellaneous
other types of CHD. Upon inclusion, targeted therapies for pulmonary arterial hypertension (PAH) included endothelin receptor antagonists, PDE-5 inhibitors, prostacyclin analogues, and soluble
guanylate cyclase stimulators. Eighty patients with Eisenmenger syndrome were treatment-naĂŻve.
While at inclusion the primary PAH treatment for the cohort was monotherapy (70% of patients),
with 30% of the patients on combination therapy, after a median observation time of 45.3 months,
the number of patients on combination therapy had increased significantly, to 50%. The use of oral
anticoagulants or antiplatelets was dependent on the underlying diagnosis or comorbidities. In the
entire COMPERA-CHD cohort, after follow-up and receiving targeted PAH therapy (n = 511), 91
patients died over the course of a 5-year follow up. The 5-year KaplanâMeier survival estimate for
CHD associated PH was significantly better than that for idiopathic PAH (76% vs. 54%; p < 0.001).
Within the CHD associated PH group, survival estimates differed particularly depending on the
underlying diagnosis and treatment status. Conclusions: In COMPERA-CHD, the overall survival of
patients with CHD associated PH was dependent on the underlying diagnosis and treatment status,
but was significantly better as than that for idiopathic PAH. Nevertheless, overall survival of patients
with PAH due to CHD was still markedly reduced compared with survival of patients with other
types of CHD, despite an increasing number of patients on PAH-targeted combination therapy
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