bluuebunny/crossref_metadata_2025 huggingface dataset:
A Flat Faint End of the Fornax Cluster Galaxy Luminosity Function
Authors: Mieske S. , Hilker M. , Infante L. , de Oliveira C. Mendes
Published: February 2008

We analyse the photometric properties of the early-type Fornax cluster dwarf galaxy population (MV > −17 mag), based on a wide field imaging study of the central cluster area in V and I band-passes with IMACS/Magellan at Las Campanas Observatory. We create a fiducial sample of ~ 100 Fornax cluster dwarf ellipticals (dEs) with −16.6 < MV < −8.8 mag in the following three steps: (1) To verify cluster membership, we measured I-band surface brightness fluctuations (SBF) distances to candidate dEs known from previous surveys; (2) We re-assessed morphological classifications for those candidate dEs that are too faint for SBF detection; and (3) We searched for new candidate dEs in the size-luminosity regime close to the resolution limit of previous surveys. The resulting fiducial dE sample follows a well-defined surface brightness – magnitude relation, showing that Fornax dEs are about 40% larger than Local Group dEs. The sample also defines a colour-magnitude relation similar to that of Local Group dEs. The early-type dwarf galaxy luminosity function in Fornax has a very flat faint end slope α ≃ −1.1 ± 0.1. We compare the number of dwarfs per unit mass with those in other environments and find that the Fornax cluster fits well into a general trend of a lack of high-mass dwarfs in more massive environments.
Can Massive Dark Haloes Destroy the Discs of Dwarf Galaxies?
Authors: Fuchs B. , Esquivel O.
Published: February 2008

Recent high-resolution simulations together with theoretical studies of the dynamical evolution of galactic disks have shown that contrary to wide-held beliefs a ‘live’, dynamically responsive, dark halo surrounding a disk does not stabilize the disk against dynamical instabilities. We generalize Toomre's Q stability parameter for a disk-halo system and show that if a disk, which would be otherwise stable, is embedded in a halo, which is too massive and cold, the combined disk-halo system can become locally Jeans unstable. The good news is, on the other hand, that this will not happen in real dark haloes, which are in radial hydrostatic equilibrium. Even very low-mass disks are not prone to such dynamical instabilities.
“Dark Galaxies” and Local Very Metal-Poor Gas-Rich Glaxies: Possible Interrelations
Authors: Pustilnik Simon A.
Published: February 2008

There are only a few “dark galaxy” candidates discovered to date in the local Universe. One of the most prominent of them is the SW component of a merging system HI 1225+01. On the other hand, the number of known very metal-poor gas-rich dwarfs similar to I Zw 18 and SBS 0335–052 E, W has grown drastically during the last decade, from a dozen and a half to about five dozen. Many of them are very gas-rich, having from ~90 to 99% of all baryons in gas. For some of such objects that have the deep photometry data, no evidences for the light of old stars are found. At least a half of such galaxies with the prominent starbursts have various evidences of interactions, including advanced mergers. This suggests that a fraction of this group objects can be a kind of very stable protogalaxies (or “dark galaxies”), which have recently experienced strong disturbances from nearby massive galaxy-size bodies. Such a collision caused the gas instabilities and its collapse with the subsequent onset of starburst. We briefly discuss the morphology and gas kinematics for the subsample of the most metal-poor dwarfs that illustrate this picture. We discuss also the relation of these rare galaxies to the processes by which “dark galaxies” can occasionally transform to optically visible galaxies.
Arecibo Survey of HI Emission from Disk Galaxies at Redshift z~0.2
Authors: Catinella B. , Haynes M. P. , Gardner J. P. , Connolly A. J. , Giovanelli R.
Published: February 2008

We present results from a targeted survey undertaken with the 305m Arecibo radiotelescope to detect HI-line emission from disk galaxies at redshift z>0.16. Among other applications, this dataset will be used to study the evolution of disk scaling relations at intermediate redshifts. Compared to optical velocity widths, HI measurements sample a larger fraction of the disks, where the rotation curves are typically flat, and are not affected by slit smearing and misalignment or by aperture effects. Thus, in contrast to studies based on optical spectroscopy, this dataset allows for a direct comparison with the local Tully-Fisher relation that is technique independent.
Radio Observations of AGN in Low Surface Brightness Galaxies
Authors: Das M. , McGaugh S. S. , Kantharia N. , Vogel S. N.
Published: February 2008

We present preliminary results of a study of the low frequency radio continuum emission from the nuclei of Giant Low Surface Brightness (LSB) galaxies. We have mapped the emission and searched for extended features such as radio lobes/jets associated with AGN activity. LSB galaxies are poor in star formation and generally less evolved compared to nearby bright spirals. This paper presents low frequency observations of 3 galaxies; PGC 045080 at 1.4 GHz, 610 MHz, 325MHz, UGC 1922 at 610 MHz and UGC 6614 at 610 MHz. The observations were done with the GMRT. Radio cores as well as extended structures were detected and mapped in all three galaxies; the extended emission may be assocated with jets/lobes associated with AGN activity. Our results indicate that although these galaxies are optically dim, their nuclei can host AGN that are bright in the radio domain.
Low Surface Brightness Galaxies Around the Hubble Deep Field South
Authors: Haberzettl L. , Bomans D. J. , Dettmar R.-J.
Published: February 2008

We present results from a study of the SFH of a sample of LSB galaxies around the HDF-S. For the selection of the LSB galaxy candidates we used color–color diagrams, from which we selected the candidates based on their different location in comparison to the HSB galaxy redshift tracks. We compared measured spectra to synthetic SEDs from synthesis evolution models. We were able to fit SEDs in the range of 2 to 5 Gyr to the spectra of the LSB galaxies, while applying the same method to a sample of HSB galaxies resulted in an averaged stellar population of about 10 to 14 Gyr. Therefore, LSB galaxies tend to show much younger averaged stellar populations. This implies that the major star formation event of LSB galaxies took place at a redshift of z ~ 0.2 to 0.4 while for HSB galaxies this tends to be at z ~ 2 to 4.
Spitzer Observations of Tidal Dwarf Galaxies
Authors: Higdon Sarah J. U. , Higdon James L.
Published: February 2008

We present Spitzer observations of Tidal Dwarf Galaxies (TDGs) in three interacting systems: NGC 5291, Arp 105 & Stephan's Quintet. The spectra show bright emission from polyaromatic hydrocarbons (PAHs), nebular lines and warm molecular hydrogen, characteristic of recent episodes of star formation. The PAH emission that falls in the IRAC 8.0 μm band leads to the TDGs having an extremely red IRAC color, with [4.5] − [8.0] > 3. The emission from PAHs is characterized by a model with mainly neutral 100-C PAH atoms.
A 500 kpc HI Tail of the Virgo Pair NGC4532/DDO137 Detected by ALFALFA
Authors: Koopmann Rebecca A.
Published: February 2008

HI observations of the Virgo Cluster pair NGC 4532/DDO 137, conducted as part of the Arecibo Legacy Fast ALFA Survey, reveal an HI feature extending ~500kpc to the southwest. The structure has a total mass of up to 7 x 108M⊙, equivalent to 10% of the pair HI mass. Optical R imaging reveals no counterparts to a level of 26.5 mag arcsec−2. The structure is likely the result of galaxy harassment.
Virgo Early-Type Dwarfs in ALFALFA
Authors: Koopmann Rebecca A.
Published: February 2008

Early-type dwarf galaxies dominate cluster populations, but their formation and evolutionary histories are poorly understood. The ALFALFA (Arecibo Legacy Fast ALFA) survey has completed observations of the Virgo Cluster in the declination range of 6 – 16 degrees. Less than 2% of the early-type dwarf population is detected, a significantly lower fraction than reported in previous papers based on more limited samples. In contrast ~30% of the irregular/BCD dwarf population is detected. The detected early-type galaxies tend to be located in the outer regions of the cluster, with a concentration in the direction of the M Cloud. Many show evidence for ongoing/recent star formation. Galaxies such as these may be undergoing morphological transition due to cluster environmental effects.
Neutral Hydrogen Gas in Star Forming Galaxies at z=0.24
Authors: Lah Philip , Chengalur Jayaram N. , Briggs Frank H. , Colless Matthew , De Propris Roberto , Pracy Michael B. , de Blok W. J. G.
Published: February 2008

We use observations from the Giant Metrewave Radio Telescope (GMRT) to measure the atomic hydrogen gas content of star-forming galaxies at z = 0.24 (i.e. a look-backtime of ~3 Gyr). To measure the HI 21 cm emission signal we stack the signal from 121 galaxies with known optical positions and redshifts. We find an average HI mass for the galaxies of (2.26 ± 0.90) × 109 M⊙. We translate this HI measurement into a cosmic density of neutral gas at z=0.24 of Ωgas = (0.91 ± 0.42) × 10−3. This value is consistent with that estimated from damped Lyα systems around this redshift.
The Distribution of ALFALFA Galaxies
Authors: Martin Ann M.
Published: February 2008

The ALFALFA2 blind HI survey will enable a census of the distribution of gas-rich galaxies in the local Universe. Sensitive to an HI mass of 107 solar masses at the distance of the Virgo cluster, ALFALFA will probe the smallest objects locally and provide a new consideration of near-field cosmology. Additionally, with a larger, cosmologically significant sample volume and wider bandwidth than previous blind surveys, a much larger number of detections in each mass bin is possible, with adequate angular resolution to eliminate the need for extensive follow-up observations. This increased sensitivity will greatly enhance the utility of cosmological probes in HI. ALFALFA will eventually measure the correlation function of HI selected galaxies in a large local volume. The larger sample and volume size of the ALFALFA dataset will also robustly measure the HI mass function (HIMF). Here, we present the preliminary results on the distribution of local gas-rich galaxies from a first ALFALFA catalog covering 540 deg2.
Dark Galaxies: How about this one?
Authors: Struve Christian , Józsa Gyula I.G. , Kenn Franz , Klein Uli , Gentile Gianfranco
Published: February 2008

We report on the (serendipitous) detection and analysis of an extremely massive HI cloud without an obvious stellar counterpart nearby the relatively isolated giant spiral galaxy NGC 1030 and present first results of this dark galaxy candidate.
The Detectability of Dark Galaxies Through Image-Splitting Effects
Authors: Zackrisson E. , Riehm T. , Lietzen H. , Möller O. , Wiik K. , Nurmi P.
Published: February 2008

In principle, dark galaxies in the dwarf-galaxy mass range may be detectable through additional, small-scale image splitting of quasars that are already known to be multiply-imaged on arcsecond scales. Here, we derive the image separations expected for dark galaxies with density profiles favoured by recent N-body simulations. The results are compared to the angular resolution of existing and planned telescopes at X-ray, optical, near-infrared and radio wavelengths.
Sediment organic carbon burial in agriculturally eutrophic impoundments over the last century
Authors: Downing J. A. , Cole J. J. , Middelburg J. J. , Striegl R. G. , Duarte C. M. , Kortelainen P. , Prairie Y. T. , Laube K. A.
Published: February 2008

We estimated organic carbon (OC) burial over the past century in 40 impoundments in one of the most intensively agricultural regions of the world. The volume of sediment deposited per unit time varied as a function of lake and watershed size, but smaller impoundments had greater deposition and accumulation rates per unit area. Annual water storage losses varied from 0.1–20% and were negatively correlated with impoundment size. Estimated sediment OC content was greatest in lakes with low ratios of watershed to impoundment area. Sediment OC burial rates were higher than those assumed for fertile impoundments by previous studies and were much higher than those measured in natural lakes. OC burial ranged from a high of 17,000 g C m−2 a−1 to a low of 148 g C m−2 a−1 and was significantly greater in small impoundments than large ones. The OC buried in these lakes originates in both autochthonous and allochthonous production. These analyses suggest that OC sequestration in moderate to large impoundments may be double the rate assumed in previous analyses. Extrapolation suggests that they may bury 4 times as much carbon (C) as the world's oceans. The world's farm ponds alone may bury more OC than the oceans and 33% as much as the world's rivers deliver to the sea.
Antarctic records of precession‐paced insolation‐driven warming during early Pleistocene Marine Isotope Stage 31
Authors: Scherer R. P. , Bohaty S. M. , Dunbar R. B. , Esper O. , Flores J.‐A. , Gersonde R. , Harwood D. M. , Roberts A. P. , Taviani M.
Published: February 2008

Precisely dated Antarctic continental margin and Southern Ocean geological records show that the early Pleistocene interglacial Marine Isotope Stage 31 (MIS‐31) was characterized by warmer than present surface waters with reduced sea‐ice and enhanced high latitude marine carbonate production. Micropaleontologic, isotopic, and paleomagnetic evidence from drill cores at 77°S (Cape Roberts Project‐1) and 53°S (ODP Site 1094) indicate circumantarctic changes in sea surface temperature and water mass stratification that are in phase with high southern latitude insolation changes during MIS‐31. These changes imply a significant, though as yet unquantifiable reduction in Antarctic ice volume. This study supports the hypothesis that the interhemispheric antiphased relationship of the precession cycle attenuates a potentially significant Antarctic ice volume signal in the deep sea oxygen isotope record. The implications are that Antarctic marine ice sheets may be more susceptible to warming and high insolation driven retreat than has been widely recognized.
Zeta potential estimation of volcanic rocks on 11 island arc‐type volcanoes in Japan: Implication for the generation of local self‐potential anomalies
Authors: Aizawa Koki , Uyeshima Makoto , Nogami Kenji
Published: February 2008

From streaming potential measurements, we deduced the zeta potential of 73 volcanic rock samples collected in 11 volcanoes where self‐potential (SP) surveys had also been conducted. Experiments with crushed rock samples and 0.001 mol/L NaCl solution showed a large variation in streaming potential coefficient, which ranged from −2860 to 2280 mV/MPa (deduced zeta potential ranged from −45.1 to 37.2 mV). Among the 73 samples, 9 samples showed positive values, and 11 samples showed small absolute values less than 10 mV. Even in a volcano, the zeta potential values of rocks were sometimes highly variable. To investigate the reason for the variation in zeta potential, we performed X‐ray fluorescence (XRF) measurements on the rock samples. However, no significant correlations between zeta potential (or isoelectric point) and weight percentage of major elements were found, implying that the zeta potential of the volcanic rocks is not controlled by chemical composition but by mineralogical composition or crystalline structure. In volcanic areas, rocks with positive or small absolute values of zeta potential, which are considered to be unusual, frequently exist in areas along with local positive SP anomalies. Although positive SP anomalies are usually interpreted as an indication of hydrothermal upflow, this correlation suggests that in addition to the groundwater flow pattern, the polarity of zeta potential should also be considered for interpretation of SP data. Therefore, in cases where detailed zeta potential measurements have not been conducted, local positive SP anomalies should be interpreted with caution.
Estimation of heat and freshwater transports in the North Pacific using high‐resolution expendable bathythermograph data
Authors: Uehara Hiroki , Kizu Shoichi , Hanawa Kimio , Yoshikawa Yasushi , Roemmich Dean
Published: February 2008

The mean heat and freshwater transports in the North Pacific subtropical gyre during 1998–2002 are estimated. High‐resolution expendable bathythermograph/expendable conductivity‐temperature‐depth (XBT/XCTD) transects (PX‐40, Honolulu to Japan; PX‐37, San Francisco to Honolulu; PX‐10, Honolulu to Guam; PX‐44, Guam to Taiwan/Hong Kong) are used to calculate geostrophic transport across each of the ship tracks. Ekman transport is estimated from satellite‐scatterometer wind stress. The mean heat and freshwater transport convergences into the northern box bounded by the PX‐40/37 transects and the Tsushima and Bering Straits are 0.26 ± 0.16 pW (pW = 1015 W) and −0.26 ± 0.11 Sv (Sv = 106 m3/s), respectively. Heat and freshwater transport convergences into the western box bounded by the PX‐40/10/44 transects and the Tsushima Strait are estimated to be 0.32 ± 0.17 pW and 0.08 ± 0.07 Sv, respectively. In both boxes, warmer waters transported inward by the Ekman flow and by the Kuroshio are compensated by the export of waters at cooler temperatures, whose peaks are found in the temperatures of the mode waters formed in the North Pacific. The salt budget is also described to consider the mechanisms of freshwater transport. Since the western box includes the region with the strongest heat loss to the atmosphere and is possibly a key region for climatic decadal variation, it is necessary to continue the high‐resolution XBT/XCTD measurement and to make an effort at improving the estimation of heat and freshwater transports in order to contribute to advancing climate studies.
Seasonal mixed layer salinity balance of the tropical North Atlantic Ocean
Authors: Foltz Gregory R. , McPhaden Michael J.
Published: February 2008

In this study the causes of the seasonal cycle of mixed layer salinity in the tropical North Atlantic Ocean are investigated from a combination of satellite, atmospheric reanalysis, and in situ data sets. Results indicate that the salinity balance varies regionally, leading to a seasonal cycle in sea surface salinity (SSS) with significant spatial inhomogeneity. For example, horizontal salinity advection plays a key role in the salinity balance of the western tropical North Atlantic (10–25°N, 50–65°W), where seasonal variations in SSS are relatively large. In contrast, in the north‐central basin (15–25°N, 20–50°W), freshening from meridional advection balances an excess of evaporation over precipitation, resulting in a very weak seasonal cycle of mixed layer salinity. Farther south (5–15°N, 20–45°W), seasonal variations of precipitation are more significant and drive a pronounced seasonal cycle of mixed layer salinity. Throughout most of the tropical North Atlantic the sum of the surface moisture flux and horizontal advection underestimates the mixed layer salinity tendency during boreal fall and winter. This is the time of year with highest wind speeds and highest negative buoyancy flux, suggesting that vertical turbulent entrainment of high‐salinity thermocline water may be important. Daily measurements from a moored buoy in the central tropical North Atlantic are consistent with this interpretation. The results of this study highlight the complexity of the seasonal salinity balance in the tropical North Atlantic Ocean and the need for continued in situ monitoring of upper ocean salinity and currents to complement future space‐based surface salinity measurements.
From Subduction to Collision: The Sunda‐Banda Arc Transition
Authors: Müller Christian , Barckhausen Udo , Ehrhardt Axel , Engels Martin , Gaedicke Christoph , Keppler Hans , Lutz Rüdiger , Lüschen Ewald , Neben Sönke , Kopp Heidrun , Flueh Ernst R. , Djajadihardja Yusuf S. , Soemantri Dzulkarnaen D. P. , Seeber Leonardo
Published: February 2008

In the aftermath of the Mw 9.3 Indian Ocean earthquake and tsunami of 26 December 2004, which killed more than 250,000 people, numerous investigations have been commissioned near the epicenter offshore northern Sumatra to evaluate future earthquake and tsunami hazards. These projects have mapped seafloor morphology and imaged deep structures and faults in order to better understand the origin of megathrust earthquakes and tsunamis in the western portion of the Sunda Arc subduction system offshore northern Sumatra [e.g., Henstock et al., 2006].

In contrast, the eastern part of the arc has received relatively little attention, even though it may be just as hazardous. Our geophysical data from the eastern Sunda Arc and the transition to the Banda Arc (Figure 1) provide evidence for recent tectonic activity and thus for a similar earthquake and tsunami risk.
New AGU Fellows
Authors: Anonymous
Published: February 2008

Fellows of AGU are members who have attained acknowledged eminence in the Earth and space sciences. On 8 December 2007, the Fellows Committee elected 51 members for the class of 2008. Candidates are nominated by colleagues and then vetted by relevant sections and focus groups, who forward the top nominees to the Fellows Committee, which comprises 11 Fellows. Members of the 2006–2008 Fellows Committee are Tuija Pulkkinen, chair, and Shaw Liu, Andrea Rinaldo, Roberta Rudnick, Barbara Romanowicz, Lawrence Mysak, Steve Running, Thomas Herring, Lisa Tauxe, Julian McCreary, and Maria Zuber.
Earth Science Instrumentation and Facilities Program Review
Authors: Jeanloz Raymond , Beck Susan L. , Lisowski Michael , Lorenzo Juan M. , Mora Claudia I. , Rimstidt J. Donald , Shirey Steven B. , Stein Seth , Wirth Karl
Published: February 2008

The Instrumentation and Facilities (IF) program of the U.S. National Science Foundation's Division of Earth Sciences (NSF/EAR) supports a remarkably broad span of research, both in the science that is addressed and in the nature of awards provided, according to a review by a Committee of Visitors on 22–24 August 2007. The present article, written by committee members, provides a synopsis of our findings to promote community‐wide discussion of the size, scope, and responsibilities of the IF program.

The IF program funds infrastructure ranging from an individual investigator's purchase of laboratory equipment to support for major, multiuser facilities requiring millions of dollars per year (Figure 1). Partial support is also provided for technicians (for up to 5 years, with a decreasing level of funding each year).
High‐Speed Solar Wind Streams: A Call for Key Research
Authors: Denton Michael H. , Borovsky Joseph E. , Horne Richard B. , McPherson Robert L. , Morley Steven K. , Tsurutani Bruce T.
Published: February 2008

The arrival of high‐speed solar wind streams (HSSs) at the Earth's magnetopause drives particle and wave phenomena that are distinct from the phenomena caused by other solar wind structures. Although HSS events do not generally produce a particularly strong ring current (the current caused by ions and electrons drifting around the Earth), they do produce storm levels of other magnetospheric phenomena (enhanced convection, heating, precipitation, relativistic electron energization, and so forth) that can persist for an extended time period (e.g., many days). These events contrast with interplanetary coronal mass ejection (ICME) events, where more transient driving (e.g., 1 day) is the norm. As such, the energy input to the magnetosphere during HSS events is comparable to, or may exceed, the energy input to the magnetosphere during ICME events.
Continental Margins: Linking Ecosystems: Impacts of Global, Local and Human Forcings on Biogeochemical Cycles and Ecosystems, IMBER/LOICZ Continental Margins Open Science Conference; Shanghai, China, 17–21 September 2007
Authors: Kelly‐Gerreyn Boris , Rabalais Nancy , Middelburg Jack , Roy Sylvie , Liu Kon‐Kee , Thomas Helmuth , Zhang Jing
Published: February 2008

More than 100 scientists from 25 countries came together to address global, regional, local, and human pressures interactively affecting continental margin biogeochemical cycles, marine food webs, and society. Continental margins cover only 12% of the global ocean area yet account for more than 30% of global oceanic primary production. In addition, continental margins are the most intensely used regions of the world's ocean for natural commodities, including productive fisheries and mineral and petroleum resources. The land adjacent to continental margins hosts about 50% of the world's population, which will bear many direct impacts of global change on coastal margins. Understanding both natural and human‐influenced alterations of biogeochemical cycles and ecosystems on continental margins and the processes (including feedbacks) that threaten sustainability of these systems is therefore of global interest.
Clement, Hardebeck, and Nimmo Receive 2007 James B. Macelwane Medals
Authors: Cane Mark A. , Clement Amy C. , Michael Angeles , Hardebeck Jeanne L. , Stevenson Dave , Nimmo Francis
Published: February 2008

I am pleased and honored to cite Amy Clement for the 2007 James B. Macelwane Medal. Amy's work has introduced new ways of thinking that altered research strategies; that is, she is an intellectual leader. Not everyone agrees with her ideas, but no paleoclimate scientist ignores them. Amy's work has been instrumental in changing the way paleoclimatologists think about the tropics and their influence on global climate. The ocean‐atmosphere dynamics concepts that she introduced to paleoclimate are now widely used.
Protein oxidation: key to bacterial desiccation resistance?
Authors: Fredrickson James K , Li Shu-mei W , Gaidamakova Elena K , Matrosova Vera Y , Zhai Min , Sulloway Heather M , Scholten Johannes C , Brown Mindy G , Balkwill David L , Daly Michael J
Published: February 2008

For extremely ionizing radiation-resistant bacteria, survival has been attributed to protection of proteins from oxidative damage during irradiation, with the result that repair systems survive and function with far greater efficiency during recovery than in sensitive bacteria. Here we examined the relationship between survival of dry-climate soil bacteria and the level of cellular protein oxidation induced by desiccation. Bacteria were isolated from surface soils of the shrub-steppe of the US Department of Energy's Hanford Site in Washington State. A total of 63 isolates were used for phylogenetic analysis. The majority of isolates were closely related to members of the genus Deinococcus, with Chelatococcus, Methylobacterium and Bosea also among the genera identified. Desiccation-resistant isolates accumulated high intracellular manganese and low iron concentrations compared to sensitive bacteria. In vivo, proteins of desiccation-resistant bacteria were protected from oxidative modifications that introduce carbonyl groups in sensitive bacteria during drying. We present the case that survival of bacteria that inhabit dry-climate soils are highly dependent on mechanisms, which limit protein oxidation during dehydration.
Functional responses of prokaryotes and viruses to grazer effects and nutrient additions in freshwater microcosms
Authors: Pradeep Ram Angia Sriram , Sime-Ngando Télesphore
Published: February 2008

For aquatic systems, there is little data on the interactions between viruses, prokaryotes, grazers and the availability of resources. We conducted a microcosm experiment using a size fractionation approach to manipulate grazers, with a purpose to examine the effects of inorganic and organic nutrients on viral and prokaryotic standing stocks and activities, and on prokaryotic community composition as assessed by fluorescent in situ hybridization (FISH) method. Experiments were performed during periods of severe phosphate (P)-limiting conditions in the oligotrophic Sep Reservoir (Massif Central, France). In the absence of nutrient addition, the presence of grazers in microcosms stimulated prokaryotic growth and viral proliferation, likely through nutrient and substrate enrichment. Addition of nutrients had a stronger effect on viral infection of prokaryotes than grazing. Addition of P led to the most pronounced increase in prokaryotic abundance, production and growth efficiency, thus providing direct evidence of P limitation of prokaryotes. Enhanced prokaryotic activity in P treatments also stimulated viral abundance and viral-induced lyses of prokaryotes. Changes in prokaryotic community composition due to nutrient additions were evident in the grazer-free samples. Prokaryotic populations hybridizing for the probes bacteria, β-Proteobacteria and α-Proteobacteria responded to nutrient enrichment with significant increases in their relative abundances, whereas cells hybridizing for Archaea and Cytophaga-Flavobacterium (now known as Bacteroidetes) probes failed to show any functional response. Cells hybridizing for the latter cluster increased towards the end of incubation period in the control samples (that is, without nutrient additions) with grazers present, suggesting the development of grazing resistant forms. From our nutrient enrichment microcosm experiments, we conclude that the presence of grazers is a stimulating factor for prokaryotic growth and viral proliferation in the plankton, probably through nutrient regeneration process.
Alterations in Hepatic Mitochondrial Compartment in a Model of Obesity and Insulin Resistance
Authors: Raffaella Crescenzo , Francesca Bianco , Italia Falcone , Marina Prisco , Giovanna Liverini , Susanna Iossa
Published: February 2008

The objective of this paper is to evaluate adaptations in hepatic mitochondrial protein mass, function and efficiency in a rat model of high‐fat diet‐induced obesity and insulin resistance that displays several correlates to human obesity. Adult male rats were fed a high‐fat diet for 7 weeks. Mitochondrial state 3 and state 4 respiratory capacities were measured in liver homogenate and isolated mitochondria by using nicotinamide adenine dinucleotide, flavin adenine dinucleotide and lipid substrates. Mitochondrial efficiency was evaluated by measuring proton leak kinetics. Mitochondrial mass was assessed by ultrastructural observations and citrate synthase (CS) activity measurements. Mitochondrial oxidative damage and antioxidant defence were also considered by measuring lipid peroxidation, aconitase and superoxide dismutase (SOD) specific activity. Whole body metabolic characteristics were obtained by measuring 24‐h oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory quotient (RQ) and nonprotein respiratory quotient (NPRQ), using indirect calorimetry with urinary nitrogen analysis. Whole body glucose homeostasis was assessed by measuring plasma insulin and glucose levels after a glucose load. Adult rats fed a high‐fat diet for 7 weeks, exhibit not only obesity, insulin resistance and hepatic steatosis, but also reduced respiratory capacity and increased oxidative stress in liver mitochondria. Our present results indicate that alterations in the mitochondrial compartment induced by a high‐fat diet are associated with the development of insulin resistance and ectopic fat storage in the liver. Our results thus fit in with the emerging idea that mitochondrial dysfunction can led to the development of metabolic diseases, such as obesity, type 2 diabetes mellitus and nonalcoholic steatohepatitis.
Waist Circumference, Not the Metabolic Syndrome, Predicts Glucose Deterioration in Type 2 Diabetes
Authors: Blaha Michael J. , Gebretsadik Tebeb , Shintani Ayumi , Elasy Tom A.
Published: February 2008

We sought to assess the relationship between the metabolic syndrome, abdominal obesity, and glucose deterioration amongst patients with type 2 diabetes. Our prospective cohort consisted of 164 adult patients with established diabetes who have a history of poor glycemic control, have just completed an intensive intervention aimed at improved control, and have demonstrated reduced HbA1c prior to enrollment. Waist circumference and presence of metabolic syndrome were assessed at baseline, and patients were followed up (median 24 months) for assessment of the study outcome, namely, time‐to‐hyperglycemic relapse, predefined as HbA1c >8% and >1% rise over baseline. Kaplan–Meier estimates of relapse‐free glucose maintenance and multivariable Cox regression models were used for quantifying the independent effects of the metabolic syndrome and waist circumference on risk of glucose deterioration. The mean baseline waist circumference was 42.9 ± 5.5 inches. Prevalence of the metabolic syndrome was 80%. During follow‐up, 39 patients (24%) experienced hyperglycemic relapse. The metabolic syndrome was not associated with time‐to‐relapse (P = 0.15). The waist circumference component by itself, however, was associated with increased likelihood of hyperglycemic relapse with an unadjusted hazard ratio of 3.4 (95% confidence interval (CI) 1.2–9.7) and a hazard ratio of 3.2 (95% CI 1.1–9.1) after adjusting for age, gender, insulin use, weight change, and physical activity level. The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII) metabolic syndrome had limited ability to predict glucose deterioration in this type 2 diabetes cohort. Waist circumference by itself, however, is a strong predictor of future glucose control, and may be a parsimonious tool for risk stratification. BMI may also be a useful predictive tool.
Renal Cytochrome P450 as a Determinant of Impaired Natriuresis by PPAR‐γ Ligands in Ovariectomized Obese Rats
Authors: Yoshioka Kyoko , Wakino Shu , Homma Koichiro , Kanda Takeshi , Tatematsu Satoru , Hasegawa Kazuhiro , Sugano Naoki , Ito Osamu , Omata Ken , Saruta Takao , Hayashi Koichi
Published: February 2008

Objective: Peroxisome proliferator–activated receptor (PPAR)‐γ ligand, pioglitazone (PIO), is reported to induce edema especially in postmenopausal women. The aim of this study was to elucidate the mechanism for PIO‐induced sodium retention and to discover the therapeutic strategy for the PIO‐induced changes in renal sodium handling.

Methods and Procedures: Zucker obese rats were ovariectomized and were given PIO for 8 weeks. Renal sodium excretion and renal expressions of several enzymes that generate natriuretic substances were examined.

Results: Sodium excretion was decreased in ovariectomized (OVX) rats that were given PIO when compared with OVX rats that were not. Urinary nitrites/nitrates excretion was decreased in OVX rats, but was restored by PIO. The expressions of nitric oxide synthases (NOSs) and cyclooxygenases‐1/2 (COX‐1/2) were unaltered. Similarly, the expression of epithelial sodium channels (ENaC), identified as a PPAR‐γ‐regulated gene product, was unaffected. In contrast, the expression of cytochrome P450 4A (CYP4A) was increased in OVX rats, and was downregulated by PIO. Co‐treatment of OVX rats with PIO and PPAR‐α ligand, fenofibrate, a putative inducer of CYP4A, restored not only the impaired sodium excretion but also the downregulated CYP4A expression.

Discussion: PIO‐induced sodium retention is specific in female OVX rats. Ovariectomy decreases renal NO production, but upregulates renal CYP4A expression to compensate for renal sodium balance. In this setting, PIO downregulates CYP4A, leading to sodium retention. Furthermore, PPAR‐α ligands can provide a novel strategy for preventing the PIO‐induced sodium retention.
Effect of 3‐Year Weight History on Blood Pressure: The Atherosclerosis Risk in Communities Study
Authors: Truesdale Kimberly P. , Stevens June , Cai Jianwen
Published: February 2008

The objective of this study was to examine the effect of weight history on blood pressure. Extant data from the Atherosclerosis Risk in Communities (ARIC) study were used to compare blood pressure in women (n = 5,675) and men (n = 4,893) with different 3‐year weight histories, but similar current BMI. We used mixed models regression adjusted for ethnicity, age, education, field center, smoking, alcohol consumption, antihypertensive medications, interval length, and BMI at follow‐up. We also examined associations between 3‐year weight history and blood pressure within weight status categories (normal weight (≥18.5 to <25.0 kg/m2), overweight (≥25.0 to <30.0 kg/m2), and obese (≥30.0 kg/m2)). We found weight history affected both systolic and diastolic blood pressures. Compared to men at the same BMI who had maintained their weight, men who had experienced a 10% weight gain over the previous 3 years had systolic and diastolic blood pressures that were 2.6 and 1.9 mm Hg higher, respectively (P < 0.001 for both). Associations in women were in the same direction, but smaller at 0.9 and 0.6 mm Hg (P < 0.001). With the exception of diastolic blood pressure in normal weight women, we found no significant interactions between weight change and current weight status. In conclusion, some of the variation in blood pressure among individuals at the same BMI may be due to weight change history. Effects of 3‐year weight change history appear to be stronger and more consistent in men than in women, and generally similar regardless of current weight status.
Trends in Obesity and Its Distribution: Data From the Northern Sweden MONICA Survey, 1986–2004
Authors: Lilja Mikael , Eliasson Mats , Stegmayr Birgitta , Olsson Tommy , Söderberg Stefan
Published: February 2008

Objective: Obesity, especially abdominal, is a risk factor for many diseases. This study explored trends in the prevalence of general and abdominal obesity, 1986–2004, in northern Sweden.

Methods and Procedures: Cross‐sectional population surveys were performed in 1986, 1990, 1994, 1999, and 2004; 250 men and 250 women aged 25–34, 35–44, 45–54, and 55–64 years (from 1994, also 65–74 years) were randomly selected; the overall participation rate was 77%. Anthropometric data were used.

Results: Weight and BMI increased in all men, most significantly in men aged 25–64 years (P < 0.0005). Weight increased in women aged 25–64 years (P < 0.005) and BMI in women aged 25–44 years (P < 0.005). Prevalence of obesity (BMI ≥ 30) increased significantly in men aged 25–44 and 55–74 years (P < 0.005; for men 65–74 years old, P < 0.05) and in women aged 25–44 years (P < 0.005). Waist circumference decreased significantly between 1986 and 1990 in all women (P < 0.005) and in men aged 55–64 years (P < 0.05). After 1990 waist circumference increased, most markedly so in women; by 2004 circumference measurements for women, and for men aged 55–64 years, were equal to those of 1986, while for men aged 25–54 years they were higher. Prevalence of abdominal obesity has increased since 1990, most markedly so in women aged 45–64 years (P < 0.0005).

Discussion: The rapid increase in both general and central obesity raises concern for the future; increasing abdominal obesity in women is particularly alarming.
Mobile Analytics for Emergency Response and Training
Authors: Kim SungYe , Maciejewski Ross , Ostmo Karl , Delp Edward J. , Collins Timothy F. , Ebert David S.
Published: February 2008

During emergency response events, situational awareness is critical in effectively managing and safe-guarding civilians and in-field personnel. To better support both command center controllers and in-field operators, we have developed a mobile visual analytics tool to help enhance situational awareness and support rapid decision making. Our mobile visual analytics tool consists of a 2D/3D visualization component, which shows personnel-related information, situational and static scene-related information, integrated multi media playback functionality for personnel outfitted with cameras, and fast-forward/rewind capabilities for reviewing events. Our current system has been employed in the evaluation of two different scenarios: a simulated evacuation of The Station nightclub fire that occurred in Rhode Island during 2003 and a testing exercise for a rescue operation in an elementary school. Our system has been deployed on a Dell Axim X51v PDA, an OQO 02, and on a Sprint PCS Vision SM smart device PPC-6700.
Multilayer bipolar field-effect transistors
Authors: Cho Shinuk , Yuen Jonathan , Kim Jin Young , Lee Kwanghee , Heeger Alan J. , Lee Sangyun
Published: February 2008

Field-effect transistors comprising a layer of regioregular poly(3-hexylthiophene) (rr-P3HT) separated from a parallel layer of the soluble fullerene,[6,6]-phenyl C61-butyric acid methyl ester (PCBM) by a layer of titanium suboxide (TiOx), are fabricated by solution processing. Because the TiOx is an electron transporting material and a hole blocking material, this multilayer architecture operates either in the p-channel mode with holes in the rr-P3HT layer or in the n-channel mode with electrons in the PCBM layer.
Microscale temperature measurement by the multispectral and statistic method in the ultraviolet-visible wavelengths
Authors: Pierre Thomas , Rémy Benjamin , Degiovanni Alain
Published: February 2008

The aim of this paper is to present a nonintrusive and optical method based on the classical thermal radiation laws for the measurement of microscale surface temperature. To overcome the diffraction limit, measurements are performed in the ultraviolet-visible range. According to the Planck’s law, emitting energy is low at these wavelengths and only a photonic flux can be measured through a cooled photomultiplier tube and a photon-counting card. The photonic flux exhibits a random character that can be described through well-known statistic laws such as Poisson or normal distributions. It is shown in this paper that the measured signal (photonic flux) agrees well with these statistics laws and that the surface temperature can be obtained either from the average or/and the standard deviation of the photonic flux. A multispectral technique is also introduced to get rid of the knowledge of the local surface emissivity, which is of particular interest for the measurement of temperature in microscale applications. Finally, temperature measurements carried out on a specific high temperature blackbody developed in our laboratory are compared with those obtained through an infrared camera and allow us to validate our facility and the proposed measurement technique.
Rotational spectroscopy and molecular structure of the 1,1,2-trifluoroethylene-acetylene complex
Authors: Leung Helen O. , Marshall Mark D. , Cashion Winn T. , Chen Vincent L.
Published: February 2008

Guided by ab initio calculations, Fourier transform microwave rotational spectra in the 6–22GHz region are obtained for the complex formed between 1,1,2-trifluoroethylene and acetylene, including the normal isotopomer, three of four singly substituted C13 species obtained in natural abundance, and using commercially available isotopic varieties of acetylene, species containing HCCD and HC13C13H. Although the ab initio calculations suggest two possible low energy planar arrangements for the molecules in the complex, only a single, unique structure is obtained from a combined analysis of the rotational constants derived from the spectra and atomic positions determined using Kraitchman [Am. J. Phys. 21, 17 (1953)] substitution coordinates. This structure is similar to that obtained for the CF2CHFHF complex [H. O. Leung and M. D. Marshall, J. Chem. Phys. 126, 114310 (2007)] in which both the primary and secondary interactions occur between the HCCH molecule and a F atom and a H atom bonded to the same carbon of CF2CHF. The 2.748(15)Å hydrogen bond has acetylene as the donor and 1,1,2-trifluoroethylene as the acceptor and forms a 104.49(15)° CF⋯H angle. The 2.8694(9)Å secondary interaction between the π bond of acetylene and the H atom geminal to the acceptor F atom causes the hydrogen bond to deviate 69.24(67)° from linearity. This large deviation from linearity and the similarity of the two intermolecular bond lengths suggest that the two interactions are becoming comparable in importance.
A smooth ℓ1-norm sparseness function for orbital based linear scaling total energy minimization
Authors: Weber Valéry , Hutter Jürg
Published: February 2008

A smooth ℓ1-norm based function to obtain a sparse representation of the orbital coefficients is introduced. This sparseness function is further parametrized with respect to unitary transformations among the occupied orbitals. Thus the function can be straightforwardly included in an optimization scheme or used on the fly during self-consistent field iterations to induce or maintain the sparsity of the orbital coefficients. As practical examples, we induce sparsity in the orbital coefficients of liquid water and bulk silicon. We also report the sparsity of the orbital coefficients of 1024 water molecules along a short Born–Oppenheimer molecular dynamics trajectory. It is observed that, after a stabilization period, the sparsity of the orbitals can be kept stable along the dynamics with small additional computational effort.
The ν1 CH stretching mode of the ketenyl (HCCO) radical
Authors: Wilhelm Michael J. , McNavage William , Groller Raymond , Dai Hai-Lung
Published: February 2008

The ν1 CH stretch, a previously uncharacterized mode of the ketenyl (HCCO) radical, has been identified at 3232cm−1 through time-resolved Fourier transform infrared emission spectroscopy of rovibrationally excited ketenyl generated, along with ethyl (CH2CH3), with near-unit quantum efficiency via the 193nm photodissociation of ethyl ethynyl ether. IR emission from the vibrationally excited photoproducts was detected with both temporal and frequency resolutions. Spectral assignments were supported by comparison with theoretical calculations as well as two-dimensional correlation analysis.
Visualizations of transition dipoles, charge transfer, and electron-hole coherence on electronic state transitions between excited states for two-photon absorption
Authors: Sun Mengtao , Chen Jianing , Xu Hongxing
Published: February 2008

The one-photon absorption (OPA) properties of donor-π–bridge-acceptor-π–bridge-donor (D-π-A-π-D)-type 2,1,3-benzothiadiazoles (BTD) were studied with two dimensional (2D) site and three dimensional (3D) cube representations. The 2D site representation reveals the electron-hole coherence on electronic state transitions from the ground state. The 3D representation shows the orientation of transition dipole moment with transition density, and the charge redistribution on the excited states with charge difference density. In this paper, we further developed the 2D site and 3D cube representations to investigate the two-photon absorption (TPA) properties of D-π-A-π-D-type BTD on electronic transitions between excited states. With the new developed 2D site and 3D cube representations, the orientation of transition dipole moment, the charge redistribution, and the electron-hole coherence for TPA of D-π-A-π-D-type BTD on electronic state transitions between excited states were visualized, which promote deeper understanding to the optical and electronic properties for OPA and TPA.
Multivariate analysis of homogeneous nucleation rate measurements. Nucleation in the p-toluic acid/sulfuric acid/water system
Authors: McGraw Robert , Zhang Renyi
Published: February 2008

Recent kinetic extensions of the nucleation theorem suggest that the logarithm of the steady-state nucleation rate has strong multilinear dependence on the log concentrations of condensable species present in the vapor phase. A further remarkable result is that the coefficients of this linear dependency provide a direct determination of the molecular content of the critical nucleus itself. Building on these results, the powerful utility of multivariate statistical methods is demonstrated here for physically based parametrization and interpretation of nucleation rate measurements. The new approach is applied to recent measurements by Zhang et al. [Science 304, 1487 (2004)] on the p-toluic acid/sulfuric acid/water ternary vapor system. A linear minimum variance parametrization for nucleation rate dependence on vapor composition, accurate over the range of the measurements, is obtained. Estimates of critical nucleus molecular composition are also presented. These suggest that a single molecule of p-toluic acid present in the critical nucleus is sufficient to trigger a ternary nucleation event. Efforts under way to apply the new methods to analysis of new particle formation in the atmosphere are discussed.