Variability in a radiolarian time series and its relationship to climate

EXTRACT (SEE PDF FOR FULL ABSTRACT): Recently, paleoceanographers have been challenged to produce reliable proxies of climate variables that can be incorporated into climate models. In developing proxies using time series of annual radiolarian species fluxes from Santa Barbara Basin, we identify groups of species associated with years of extreme sea surface temperatures and sea level heights.

Oceanographic variability at Clipperton Atoll since the 1880s: stable isotopic evidence from massive corals [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Clipperton Atoll (10°18'N, 109°13'W), lies within the eastern Pacific elongated warm water pool centered at 10°N and is situated at the boundary of the North Equatorial Counter-Current (NECC) and westward-flowing eddy currents moving away from Central America. ... Fifteen coral cores were collected from massive heads of Porites lobata in April 1994 for the purpose of reconstructing oceanographic and climatic conditions at this open ocean site in the eastern Pacific.

Decadal hydroclimatic variability in the western coastal United States: temporal and spatial variations in precipitation, streamflow, and lake level

EXTRACT (SEE PDF FOR FULL ABSTRACT): We have analyzed streamflow variations recorded at 15 USGS gauging stations in California during the past 90 years or so. The anomalies (departures from the 1960-1990 mean discharge) of streamflow on annual-to-decadal time scales are strongly correlated with precipitation anomalies in each drainage basin. ... Although causes of the decadal climate (precipitation) variability are not known with certainty, the use of streamflow records may help us understand the relative strengths of moisture sources and shift of the jet stream in atmospheric circulation.

Variability in the distribution of planktonic fish eggs and larvae in the nearshore waters off Bombay

Distribution of planktonic fish eggs and larvae in the nearshore waters off Bombay was studied during November 1979 to December 1980. Monthly samples were collected along three transects (Versova, Mahim and Thana) covering eleven stations which represented different environmental conditions. Fish eggs and larvae were common in the area of study with maximum abundance in December 1979 and April/August 1980. Mean density of fish eggs was maximum along the Mahim transect while population of larvae was more in the Versova transect. Total number of families of fish larvae represented in the collections increased from nearshore to offshore area.

Seasonal variability in penaeid prawn larval abundance in the Mandovi and Zuari estuaries, Goa

Seasonal variations in the occurrence and abundance of penaeid prawn larvae in the Mandovi and Zuari estuaries of Goa were studied. Larvae and post-larvae of commercially important species viz. Metapenaeus dobsoni (Miers), M.affinis (H. Milne Edwards). M. Monoceros (Fabricius), Penaeus merguiensis de Man and Parapenaeopsis stylifera (H. Milne Edwards) were recorded in that order of abundance. Protozoea and mysis stages were dominant in surface zooplankton collections while the post-larvae were more in the bottom samples. Based on larval density, M. dobsoni appeared to be a continuous breeder. The active spawning periods in other species were during the late post-monsoon and pre-monsoon seasons varying with the species. Peak recruitment of post-larvae in the estuaries was observed mostly during southwest monsoon months (June to September). Penaeid prawn larval ingression was more in the Zuari estuary compared to the Mandovi estuary. Their numerical abundance gradually decreased towards the upstream areas. The feasibility of large scale collection of penaeid prawn larvae for aquaculture is indicated.

Variability of nanoindentation responses of bone and artificial bone-like composites

Nanoindentation is a popular technique for measuring the intrinsic mechanical response of bone and has been used to measure a single-valued elastic modulus. However, bone is a composite material with 20-80 nm hydroxyapatite plates embedded in a collagen matrix, and modern instrumentation allows for measurements at these small length scales. The present study examines the indentation response of bone and artificial gelatin-apatite nanocomposite materials across three orders of magnitude of lengthscale, from nanometers to micrometers, to isolate the composite phase contributions to the overall response. The load-displacement responses were variable and deviated from the quadratic response of homogeneous materials at small depths. The distribution of apparent elastic modulus values narrowed substantially with increasing indentation load. Indentation of particulate nanocomposites was simulated using finite element analysis. Modeling results replicated the convergence in effective modulus seen in the experiments. It appears that the apatite particles are acting as the continuous ("matrix") phase in bone and nanocomposites. Copyright © 2004 by ASME.

MicroRNA regulation and the variability of human cortical gene expression

Understanding the driving forces of gene expression variation within human populations will provide important insights into the molecular basis of human phenotypic variation. In the genome, the gene expression variability differs among genes, and at prese

Long-term changes and variability of monthly extreme temperatures in India

Extreme temperatures are changing worldwide together with changes in the mean temperatures. This study investigates the long-term trends and variations of the monthly maximum and minimum temperatures and their effects on seasonal fluctuations in various climatological regions in India. The magnitude of the trends and their statistical significance were determined by parametric ordinary least square regression techniques and the variations were determined by the respective coefficient of variations. The results showed that the monthly maximum temperature increased, though unevenly, over the last century. Minimum temperature changes were more variable than maximum temperature changes, both temporally and spatially, with results of lesser significance. The results of this study are good indicators of Indian climate variability and its changes over the last century. © Springer-Verlag 2009.

Bayesian classification of acoustical waveforms under environmental variability

We present in this paper a new multivariate probabilistic approach to Acoustic Pulse Recognition (APR) for tangible interface applications. This model uses Principle Component Analysis (PCA) in a probabilistic framework to classify tapping pulses with a high degree of variability. It was found that this model, achieves a higher robustness to pulse variability than simpler template matching methods, specifically when allowed to train on data containing high variability. © 2011 IEEE.

Probabilistic computation in human perception under variability in encoding precision.

A key function of the brain is to interpret noisy sensory information. To do so optimally, observers must, in many tasks, take into account knowledge of the precision with which stimuli are encoded. In an orientation change detection task, we find that encoding precision does not only depend on an experimentally controlled reliability parameter (shape), but also exhibits additional variability. In spite of variability in precision, human subjects seem to take into account precision near-optimally on a trial-to-trial and item-to-item basis. Our results offer a new conceptualization of the encoding of sensory information and highlight the brain's remarkable ability to incorporate knowledge of uncertainty during complex perceptual decision-making.