168 research outputs found
Decadal-centennial scale monsoon variations in the Arabian Sea during the Early Holocene
An essential prerequisite for the prediction of future climate change due to anthropogenic input is an understanding of the natural processes that control Earth's climate on timescales comparable to human-lifespan. The Early Holocene period was chosen to study the natural climate variability in a warm interval when solar insolation was at its maximum. The monsoonal system of the Tropics is highly sensitive to seasonal variations in solar insolation, and consequently marine sediments from the region are a potential monitor of past climate change. Here we show that during the Early Holocene period rapid
Brownian markets
Financial market dynamics is rigorously studied via the exact generalized
Langevin equation. Assuming market Brownian self-similarity, the market return
rate memory and autocorrelation functions are derived, which exhibit an
oscillatory-decaying behavior with a long-time tail, similar to empirical
observations. Individual stocks are also described via the generalized Langevin
equation. They are classified by their relation to the market memory as heavy,
neutral and light stocks, possessing different kinds of autocorrelation
functions
Characterization of DLK1(PREF1)+/CD34+ cells in vascular stroma of human white adipose tissue
AbstractSorting of native (unpermeabilized) SVF-cells from human subcutaneous (s)WAT for cell surface staining (cs) of DLK1 and CD34 identified three main populations: ~10% stained cs-DLK1+/cs-CD34−, ~20% cs-DLK1+/cs-CD34+dim and ~45% cs-DLK1−/cs-CD34+. FACS analysis after permeabilization showed that all these cells stained positive for intracellular DLK1, while CD34 was undetectable in cs-DLK1+/cs-CD34− cells. Permeabilized cs-DLK1−/cs-CD34+ cells were positive for the pericyte marker α-SMA and the mesenchymal markers CD90 and CD105, albeit CD105 staining was dim (cs-DLK1−/cs-CD34+/CD90+/CD105+dim/α-SMA+/CD45−/CD31−). Only these cells showed proliferative and adipogenic capacity. Cs-DLK1+/cs-CD34− and cs-DLK1+/cs-CD34+dim cells were also α-SMA+ but expressed CD31, had a mixed hematopoietic and mesenchymal phenotype, and could neither proliferate nor differentiate into adipocytes. Histological analysis of sWAT detected DLK1+/CD34+ and DLK1+/CD90+ cells mainly in the outer ring of vessel-associated stroma and at capillaries. DLK1+/α-SMA+ cells were localized in the CD34− perivascular ring and in adventitial vascular stroma. All these DLK1+ cells possess a spindle-shaped morphology with extremely long processes. DLK1+/CD34+ cells were also detected in vessel endothelium. Additionally, we show that sWAT contains significantly more DLK1+ cells than visceral (v)WAT. We conclude that sWAT has more DKL1+ cells than vWAT and contains different DLK1/CD34 populations, and only cs-DLK1−/cs-CD34+/CD90+/CD105+dim/α-SMA+/CD45−/CD31− cells in the adventitial vascular stroma exhibit proliferative and adipogenic capacity
Precision of the current methods to measure the alkenone proxy UK'37 and absolute alkenone abundance in sediments : results of an interlaboratory comparison study
Measurements of the UK'37 index and the absolute abundance of alkenones in marine sediments are increasingly used in paleoceanographic research as proxies of past sea surface temperature and haptophyte (mainly coccolith-bearing species) primary productivity, respectively. An important aspect of these studies is to be able to compare reliably data obtained by different laboratories from a wide variety of locations. Hence the intercomparability of data produced by the research community is essential. Here we report results from an anonymous interlaboratory comparison study involving 24 of the leading laboratories that carry out alkenone measurements worldwide. The majority of laboratories produce data that are intercomparable within the considered confidence limits. For the measurement of alkenone concentrations, however, there are systematic biases between laboratories, which might be related to the techniques employed to quantify the components. The maximum difference between any two laboratories for any two single measurements of UK'37 in sediments is estimated, with a probability of 95%, to be <2.18C. In addition, the overall within-laboratory precision for the UK'37 temperature estimates is estimated to be <1.68C (95% probability). Similarly, from the analyses of alkenone concentrations the interlaboratory reproducibility is estimated at 32%, and the repeatability is estimated at 24%. The former is compared to a theoretical estimate of reproducibility and found to be excessively high. Hence there is certainly scope and a demonstrable need to improve reproducibility and repeatability of UK'37 and especially alkenone quantification data across the community of scientists involved in alkenone research
Sea surface temperatures of the western Arabian Sea during the last deglaciation.
In this study we present a sea surface temperature (SST) record from the western Arabian Sea for the last\ud
20,000 years. We produced centennial-scale d18O and Mg/Ca SST time series of core NIOP929 with focus on\ud
the glacial-interglacial transition. The western Arabian Sea is influenced by the seasonal NE and SW monsoon\ud
wind systems. Lowest SSTs occur during the SW monsoon season because of upwelling of cold water, and\ud
highest SSTs can be found in the low-productivity intermonsoon season. The Mg/Ca-based temperature record\ud
reflects the integrated SST of the SW and NE monsoon seasons. The results show a glacial-interglacial SST\ud
difference of 2C, which is corroborated by findings from other Arabian Sea cores. At 19 ka B.P. a yet\ud
undescribed warm event of several hundred years duration is found, which is also reflected in the d18O record. A\ud
second centennial-scale high SST/low d18O event is observed at 17 ka B.P. This event forms the onset of the\ud
stepwise yet persistent trend toward Holocene temperatures. Highest Mg/Ca-derived SSTs in the NIOP929\ud
record occurred between 13 and 10 ka B.P. Interglacial SST is 24C, indicating influence of upwelling. The\ud
onset of Arabian Sea warming occurs when the North Atlantic is experiencing minimum temperatures. The rapid\ud
temperature variations at 19, 17, and 13 ka B.P. are difficult to explain with monsoon changes alone and are\ud
most likely also linked to regional hydrographic changes, such as trade wind induced variations in warm water\ud
advection
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Precision of the current methods to measure the alkenone proxy U₃₇ K’ and absolute alkenone abundance in sediments: results of an interlaboratory comparison study
Measurements of the U₃₇ K’ index and the absolute abundance of alkenones in marine sediments are increasingly used in paleoceanographic research as proxies of past sea surface
temperature and haptophyte (mainly coccolith-bearing species) primary productivity, respectively. An
important aspect of these studies is to be able to compare reliably data obtained by different laboratories
from a wide variety of locations. Hence the intercomparability of data produced by the research
community is essential. Here we report results from an anonymous interlaboratory comparison study
involving 24 of the leading laboratories that carry out alkenone measurements worldwide. The majority
of laboratories produce data that are intercomparable within the considered confidence limits. For the measurement of alkenone concentrations, however, there are systematic biases between laboratories,
which might be related to the techniques employed to quantify the components. The maximum
difference between any two laboratories for any two single measurements of U₃₇ K’ in sediments is
estimated, with a probability of 95%, to be <2.1°C. In addition, the overall within-laboratory precision
for the U₃₇ K’ temperature estimates is estimated to be <1.6°C (95% probability). Similarly, from the
analyses of alkenone concentrations the interlaboratory reproducibility is estimated at 32%, and the
repeatability is estimated at 24%. The former is compared to a theoretical estimate of reproducibility
and found to be excessively high. Hence there is certainly scope and a demonstrable need to improve
reproducibility and repeatability of U₃₇ K’ and especially alkenone quantification data across the
community of scientists involved in alkenone research
Trženjska strategija za prodajo avtomobilskih nadomestnih delov blagovne znamke Motrio
The literature on information aggregation predicts that market growth
unambiguously reduces uncertainty about the value of traded goods. The
results were developed within the classical model, which assumes that
traders’ values for the exchanged good are determined by
fundamental (common) shocks. At the same time, design innovation in
contemporaneous markets seems to exploit demand interdependence among
agents with similar tastes or common information sharing (e.g., Facebook
ads, the practice of customer targeting). This paper demonstrates that
with heterogeneous interdependence among agents’ values or noise
in signals about values, opportunities to innovate in smaller or less
connected (in the network-theoretic sense) markets may dominate those in
larger or better connected markets
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