Weekly Gridded Aquarius L-band Radiometer-Scatterometer Observations and Salinity Retrievals over the Polar Regions - Part 2: Initial Product Analysis

Following the development and availability of Aquarius weekly polar-gridded products, this study presents the spatial and temporal radiometer and scatterometer observations at L band (frequency1.4 GHz) over the cryosphere including the Greenland and Antarctic ice sheets, sea ice in both hemispheres, and over sub-Arctic land for monitoring the soil freeze-thaw state. We provide multiple examples of scientific applications for the L-band data over the cryosphere. For example, we show that over the Greenland Ice Sheet, the unusual 2012 melt event lead to an L-band brightness temperature (TB) sustained decrease of 5 K at horizontal polarization. Over the Antarctic ice sheet, normalized radar cross section (NRCS) observations recorded during ascending and descending orbits are significantly different, highlighting the anisotropy of the ice cover. Over sub-Arctic land, both passive and active observations show distinct values depending on the soil physical state (freeze-thaw). Aquarius sea surface salinity (SSS) retrievals in the polar waters are also presented. SSS variations could serve as an indicator of fresh water input to the ocean from the cryosphere, however the presence of sea ice often contaminates the SSS retrievals, hindering the analysis. The weekly grided Aquarius L-band products used a redistributed by the US Snow and Ice Data Center at http:nsidc.orgdataaquariusindex.html, and show potential for cryospheric studies

Infrared studies of the orientation process in polyethylene terephthalate, part II STATUS report, Oct. 31, 1965 - Apr. 30, 1966

Infrared determination of orientation process in polyethylene terephthalat

Dusty Cometary Globules in W5

We report the discovery of four dusty cometary tails around low mass stars in two young clusters belonging to the W5 star forming region. Fits to the observed emission profiles from 24 micron observations with the Spitzer Space Telescope give tail lifetimes < 30 Myr, but more likely < 5 Myr. This result suggests that the cometary phase is a short lived phenomenon, occurring after photoevaporation by a nearby O star has removed gas from the outer disk of a young low mass star (see also Balog et al. 2006; Balog et al. 2008).Comment: 11 pages, 3 figures. Accepted for publication to ApJ Letter

Use of the Ober2 system for analysis of eye movements made during reading

Introduction: The Ober2 system uses infrared reflections to record and analyze eye movements made during reading. The system\u27s ability to analyze data from normal subjects, and the reliability of the data produced by subjects who read standard paragraphs were investigated in this study. Subjects: Forty-two college students and 20 junior high students participated in the project. All were self-reported normal readers. Methods: Subjects read 5 different paragraphs during each of two sessions. Ober2 analysis was attempted for each paragraph; analysis of all 10 paragraphs was successful for 38 percent of the college subjects and 20 percent of the junior high subjects. Use of manual calibration procedures did not allow any additional data to be analyzed by the Ober2 system. Results: Data from 30% of the paragraph presentations could not be analyzed by the Ober2. When analysis was successful, grade equivalent scores based on fixations, span of recognition, regressions, fixation duration, and reading rate were provided. Using mean grade equivalents from the 16 college subjects for whom all 10 paragraphs could be analyzed, significant differences were found between results for two of the test paragraphs. Split-half reliability coefficients for grade equivalent data from the two sessions ranged from 0.84 to 0.95. Conclusions: Although the Ober2 can provide valuable information on eye movements made during reading, problems exist with respect to its ability to analyze data. The analysis failures that occurred for approximately one-third of the paragraph presentations were frustrating and time consuming. With respect to the standard paragraphs, significant grade equivalent differences were found between several of them. These results suggest that caution be used when interpreting data from the Ober2 reading analysis system

The acute neurotoxicity of mefloquine may be mediated through a disruption of calcium homeostasis and ER function in vitro

BACKGROUND: There is no established biochemical basis for the neurotoxicity of mefloquine. We investigated the possibility that the acute in vitro neurotoxicity of mefloquine might be mediated through a disruptive effect of the drug on endoplasmic reticulum (ER) calcium homeostasis. METHODS: Laser scanning confocal microscopy was employed to monitor real-time changes in basal intracellular calcium concentrations in embryonic rat neurons in response to mefloquine and thapsigargin (a known inhibitor of the ER calcium pump) in the presence and absence of external calcium. Changes in the transcriptional regulation of known ER stress response genes in neurons by mefloquine were investigated using Affymetrix arrays. The MTT assay was employed to measure the acute neurotoxicity of mefloquine and its antagonisation by thapsigargin. RESULTS: At physiologically relevant concentrations mefloquine was found to mobilize neuronal ER calcium stores and antagonize the pharmacological action of thapsigargin, a specific inhibitor of the ER calcium pump. Mefloquine also induced a sustained influx of extra-neuronal calcium via an unknown mechanism. The transcription of key ER proteins including GADD153, PERK, GRP78, PDI, GRP94 and calreticulin were up-regulated by mefloquine, suggesting that the drug induced an ER stress response. These effects appear to be related, in terms of dose effect and kinetics of action, to the acute neurotoxicity of the drug in vitro. CONCLUSIONS: Mefloquine was found to disrupt neuronal calcium homeostasis and induce an ER stress response at physiologically relevant concentrations, effects that may contribute, at least in part, to the neurotoxicity of the drug in vitro

How Does Restored Habitat For Chinook Salmon ( Oncorhynchus Tshawytscha ) In The Merced River In California Compare With Other Chinook Streams?

The amount of time and money spent on restoring rivers for declining populations of salmon has grown substantially in recent decades. But despite the infusion of resources, many studies suggest that salmon populations are continuing to decline, leading some to question the effectiveness of restoration efforts. Here we examine whether a particular form of salmon restoration—channel reconfiguration with gravel augmentation—generates physical and biological habitat that is comparable with other streams that support salmon. We compared a suite of habitat features known to influence the various life stages of Chinook salmon in a restoration project in California's Merced River with 19 other streams that also support Chinook that we surveyed in the same geographic region. Our survey showed that riffle habitats in the restored site of the Merced River have flow discharge and depth, substrate and food web characteristics that cannot be distinguished from other streams that support Chinook, suggesting that these factors are unlikely to be bottlenecks to salmon recovery in the Merced. However, compared with other streams in the region, the Merced has minimal riparian cover, fewer undercut banks, less woody debris and higher water temperatures, suggesting that these factors might limit salmon recovery. After identifying aspects in the Merced that differ from other streams, we used principal components analysis to correlate salmon densities to independent axes of environmental variation measured during our survey. These analyses suggested that salmon densities tend to be greatest in streams that have more undercut banks and woody debris and lower water temperatures. These are the same environmental factors that appear to be missing from the Merced River restoration effort. Collectively, our results narrow the set of candidate factors that may limit salmon recovery in channel reconfiguration restoration efforts. Copyright © 2012 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97512/1/rra1604.pd

Cotunneling thermopower of single electron transistors

We study the thermopower of a quantum dot weakly coupled to two reservoirs by tunnel junctions. At low temperatures the transport through the dot is suppressed by charging effects (Coulomb blockade). As a result the thermopower shows an oscillatory dependence on the gate voltage. We study this dependence in the limit of low temperatures where the transport through the dot is dominated by the processes of inelastic cotunneling. We also obtain a crossover formula for intermediate temperatures which connects our cotunneling results to the known sawtooth behavior in the sequential tunneling regime. As the temperature is lowered, the amplitude of thermopower oscillations increases, and their shape changes qualitatively.Comment: 9 pages, including 4 figure

Photoassociation of cold atoms with chirped laser pulses: time-dependent calculations and analysis of the adiabatic transfer within a two-state model

This theoretical paper presents numerical calculations for photoassociation of ultracold cesium atoms with a chirped laser pulse and detailed analysis of the results. In contrast with earlier work, the initial state is represented by a stationary continuum wavefunction. In the chosen example, it is shown that an important population transfer is achieved to $\approx 15$ vibrational levels in the vicinity of the v=98 bound level in the external well of the $0_g^-(6s+6p_{3/2})$ potential. Such levels lie in the energy range swept by the instantaneous frequency of the pulse, thus defining a ``photoassociation window''. Levels outside this window may be significantly excited during the pulse, but no population remains there after the pulse. Finally, the population transfer to the last vibrational levels of the ground $a^3\Sigma_u^+$(6s + 6s) is significant, making stable molecules. The results are interpreted in the framework of a two state model as an adiabatic inversion mechanism, efficient only within the photoassociation window. The large value found for the photoassociation rate suggests promising applications. The present chirp has been designed in view of creating a vibrational wavepacket in the excited state which is focussing at the barrier of the double well potential.Comment: 49 pages, 9 figures, submitted to Phys. Rev.

Seychelles warblers: complexities of the helping paradox

IntroductionThe Seychelles warbler (Acrocephalus sechellensis), a passerine endemic to the Seychelles archipelago, is a facultatively cooperative breeder that lives either in pairs or small groups. Breeding groups normally consist of a dominant pair and one to three subordinates, although up to nine have been observed. Subordinates can be of either sex, and are often offspring that have delayed dispersal and remained in their natal territory (Komdeur 1992; Richardson et al. 2002; Eikenaar et al. 2008, 2010). By the 1960s the last remnant population of this then critically endangered species was confined to Cousin Island (Figure 12.1). Subsequent conservation actions, including the restoration of forest habitat and the establishment of new populations through translocations, have provided unique opportunities to study the evolutionary ecology of cooperative breeding in this species. We have followed the entire world population of the Seychelles warbler since our study started in 1981. In 1997, however, we increased the intensity of work on Cousin and since then nearly all individuals, including fledglings, have been captured, ringed, blood sampled, sexed, and monitored for breeding and status. Molecular tools have been used to assign the sex and genetic parentage of young birds and to determine levels of relatedness between individuals. In addition, a comprehensive set of behavioral, life history, and annual fitness parameters have been recorded for nearly all individuals, providing important opportunities for assessing changes in social behavior. The lack of interisland dispersal (Komdeur et al. 2004a), combined with sampling of the entire population, provides a rare opportunity to monitor the survival, reproduction, and lifetime fitness of all individuals within the population. Our long-term research program into cooperative breeding, hand-in-hand with conservation actions, has created an experimental system in which we can attempt to unravel the factors that alter the cost-benefit trade-offs of cooperative breeding. Over time, this system has become proof of the power of the experimental methods and of the corrective value of long-term studies, where iterative examination with longer-term data sheds new insights on short-term findings. Here we detail various findings that have allowed us to uncover how changing social and ecological factors influence the form and function of reproductive competition and cooperation in the Seychelles warbler. We also outline how molecular genetic tools have given us a better understanding of the species’ cooperative breeding system and the selective factors that favor switching between different forms of cooperative and independent breeding