bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution of the MBH–σ and MBH–Lbulge Relations
Authors: Woo J.-H. , Bennert N. V. , Treu T. , Malkan M. , Blandford R.
Published: June 2010

To constrain the origin of scaling relations between black hole mass and galaxy properties, i.e., stellar velocity dispersion and bulge luminosity, we investigate the evolution of scaling relations in the past 6 Gyrs. Over the last three years, we have obtained high signal-to-noise ratio Keck spectra of ~ 50 intermediate luminosity broad-line AGNs at z ~ 0.4 and z ~ 0.6, to measure stellar velocity dispersion, and HST (ACS and NICMOS) images of the same objects (~ 40 so far), to measure bulge luminosity from the two-dimensional AGN-galaxy decomposition analysis. In this paper, we will summarize the main results on the MBH–σ and MBH–bulge luminosity relations and their evolution to the present-day universe. The measured scaling relations show that the relations have evolved significantly in the past 6 billion years, and that black hole growth predates the final galaxy assembly.
Quasar Mass Functions Across Cosmic Time
Authors: Vestergaard Marianne
Published: June 2010

I present mass functions of actively accreting black holes detected in different quasar surveys which in concert cover a wide range of cosmic history. I briefly address what we learn from these mass functions. I summarize the motivation for such a study and the methods by which we determine black hole masses.
Advection-Dominated Accretion, Jets, and the Spectral Energy Distribution of LINERs
Authors: Nemmen Rodrigo S. , Storchi-Bergmann Thaisa , Eracleous Michael , Yuan Feng
Published: June 2010

Low-luminosity active galactic nuclei (LLAGNs) represent the bulk of the AGN population in the present-day universe and they trace low-level accreting supermassive black holes. The observational properties of LLAGNs suggest that their central engines are intrinsically different from those of more luminous AGNs. It has been suggested that accretion in LLAGNs occurs via an advection-dominated accretion flow (ADAF) associated with strong jets. In order to probe the accretion physics in LLAGNs as a class, we model the multiwavelength spectral energy distributions (SEDs) of 24 LINERs (taken from a recent compilation by Eracleous et al.) with a coupled accretion-jet model. The accretion flow is modeled as an inner ADAF outside of which there is a truncated standard thin disk. These SEDs include radio, near-IR to near-UV HST data, and Chandra X-ray data. We find that the radio emission is severely underpredicted by ADAF models but can be explained by the relativistic jet. The origin of the X-ray radiation in most sources can be explained by three distinct scenarios: the X-rays can be dominated by emission from the ADAF, the jet, or from both components contributing at similar levels. From the model fits, we estimate important parameters of the central engine of LINERs, such as the mass accretion rate — relevant for studies of the feeding of AGNs — and the mass-loss rate in the jet and the jet power — relevant for studies of the kinetic feedback from jets.
Origin of the Gas in the Extended Narrow-Line Region of Nearby Seyfert Galaxies: The Case of Mrk 6
Authors: Cracco V. , Ciroi S. , Di Mille F. , Vaona L. , Rafanelli P. , Moiseev A. V. , Smirnova A. A.
Published: June 2010

Ionization cones are one of the most important pieces of evidence supporting the AGN unified model (Antonucci & Miller 1985; Urry & Padovani 1995). Until now, the physical processes at work in the cones are not completely understood. A still open question concerns the origin of the gas. To study the origin of the ionized gas, we first selected a sample of nearby (z<0.03) Seyfert galaxies showing extended [O iii] λ5007 emission. We then observed these galaxies with the MultiPupil Fiber Spectrograph (MPFS) at the 6-m telescope of the Special Astrophysical Observatory (Russia). Here we present very preliminary results on the properties of the narrow-line region (NLR) of the intermediate Seyfert galaxy Mrk 6.
Optical Flares from the Tidal Disruption of Stars by Massive Black Holes
Authors: Strubbe Linda E. , Quataert Eliot
Published: June 2010

A star that wanders too close to a massive black hole (BH) is shredded by the BH's tidal gravity. Stellar gas falls back to the BH, releasing a flare of energy. In anticipation of upcoming transient surveys, we predict the light curves and spectra of tidal flares as a function of time, highlighting the unique signatures of tidal flares in the optical and near-IR. Some of the gas initially bound to the BH is likely blown away when the fallback rate is super-Eddington at early times. This outflow produces an optical luminosity comparable to that of a supernova (Figure 1, left panel); such events have durations of ~ 10 days and may have been missed in supernova searches that exclude the nuclear regions of galaxies. When the fallback rate subsides below Eddington, the gas accretes onto the BH via a thin disk whose emission peaks in the UV to soft X-rays. Some of this emission is reprocessed by the unbound stellar debris, producing a spectrum of very broad emission lines, with no corresponding narrow forbidden lines (center panel). These lines are strongest for BHs with MBH ~ 105–106M⊙ and thus optical surveys are particularly sensitive to the lowest mass BHs in galactic nuclei. Calibrating our models to ROSAT and GALEX observations, we predict detection rates for Pan-STARRS, Palomar Transit Factory, and LSST (right panel) and highlight observational challenges in the optical. Pan-STARRS should detect at least several events per year — many more if current theoretical models of super-Eddington outflows are correct. These surveys will significantly improve our knowledge of stellar dynamics in galactic nuclei, the physics of super-Eddington accretion, the demography of intermediate mass BHs, and the role of tidal disruption in the growth of massive BHs.
Highly Ionized Gas as a Diagnostic of the Inner NLR
Authors: Ward M. J. , Mullaney J. , Jin C. , Davies R.
Published: June 2010

The spectra of AGN, from the ultraviolet to the near infrared, exhibit emission lines covering a wide range of ionization states, from neutral species such as [O i] λ 6300, up to [Fe iv] λ 5303. Here we report on some recent studies of the properties of highly ionized lines (HILs), plus two case studies of individual objects. Future IFU observations at high spatial and good spectral resolution will probe the excitation and kinematics of the gas in the zone between the extended NLR and unresolved BLR. Multi-component SED fitting can be used to link the source of photoionization with the strengths and ratios of the HILs.
Confucian Values and Elite Support for Liberal Democracy in Taiwan: The Perils of Priestly Religion
Authors: Fetzer Joel S. , Soper J. Christopher
Published: June 2010

It is widely recognized that religious institutions and values play a prominent political role in various countries around the world. What is less clear is the degree to which other prominent ideologies perform an analogous role in regions where they predominate. The purpose of this article is to explore the relationship between Confucianism and liberal democracy in Taiwan. As the most important belief system in Taiwan and, indeed, in much of East Asia, Confucianism has provided a model of civic behavior for centuries, performing a largely priestly role. What is less apparent is whether Confucianism inhibited or promoted the development of liberal democracies in the region. While an extensive theoretical debate exists on this question, virtually no work analyzes how Confucianism has been understood by political actors on the ground. The data for this study consist of interviews with 27 politicians, democracy activists, Confucianism scholars, and journalists in Taiwan. The article tests whether or not, in the minds of these key political and cultural leaders, Confucian values are an aid or a hindrance to their efforts to promote liberal democracy. The concluding section discusses the implications of the empirical results for East Asian countries and addresses the parallels between Confucianism as an ideology in East Asia and the religious institutions and values in Western countries.
Array analysis and precise source location of deep tremor in Cascadia
Authors: La Rocca Mario , Galluzzo Danilo , Malone Steve , McCausland Wendy , Del Pezzo Edoardo
Published: June 2010

We describe a new method to estimate the S‐P time of tremor‐like signals and its application to the nonvolcanic tremor recorded in July 2004 by three dense arrays in Cascadia. The cross correlation between vertical and horizontal components indicates that very often the high‐amplitude tremor signal contains sequences of P and S waves characterized by constant S‐P times (TS‐P) in the range 3.5–7 s. A detailed observation of the three component seismograms stacked over the array stations confirms the presence of P and S wave sequences. The knowledge of the TS‐P poses a strong constrain on the source‐array distance, which dramatically reduces the uncertainty on source locations when used with more traditional array processing techniques. Data were analyzed using the zero lag cross‐correlation technique (ZLCC) to estimate the propagation properties of the most correlated phases in the wavefield. Detailed polarization analyses were computed using the covariance matrix method in the time domain. Polarization parameters, joint with the results of ZLCC, allows for the discrimination between P and S coherent waves. Results show that the tremor wavefield is composed mostly by shear waves, although a consistent amount of coherent P waves is often observable. The comparison of the back azimuth at the three arrays indicate that the source of deep tremor migrates over a wide area, and often many independent sources located far from each other are active at the same time. The tremor source was located by a probabilistic method that uses the results of ZLCC, given a velocity model. When available, the inclusion of the TS‐P time in the location procedure strongly reduces the depth range, with a distribution of hypocenters very near the subduction interface. This result, significantly different compared with previous less precise locations, makes the Cascadia nonvolcanic tremor more similar to the nonvolcanic tremor recorded in Japan, at least in cases of measurable TS‐P. The polarization azimuth aligned with the slow slip direction and the source located on the plate interface indicate that deep tremor and slow slip are two different manifestations of a common phenomenon related with the subduction dynamics.
Continental degassing flux of 4He and its variability
Authors: Torgersen Thomas
Published: June 2010

The existing measures of the 4He flux from the Earth's continental solid surface have been evaluated collectively. The lognormal mean of continental crustal flux measurements (n = 33) globally covering many geological environments is 4.18 × 1010 4He atoms m−2 s−1 with an estimated one sigma variance of */45X based on an assumption of symmetric error bars (lognormal distribution provides a standard deviation with a multiplication or division factor (*/) by which the mean may statistically vary). The range of the continental 4He degassing flux (95th percentile) increases with decreasing time scales (to */∼106X at 0.5 year) and decreasing space scales (to */∼106X at 1 km). The statistics can be interpreted as reflecting natural variability and suggest that the mechanisms transporting the crustal helium degassing flux contain a high degree of both spatial and temporal variability. This lognormal mean of the continental degassing flux of 4He as well as the (n = 271) estimate of degassing from Precambrian Shield lakes are both approximately equivalent to the radiogenic production rate for 4He in the whole crust. Large‐scale vertical mass transport in continental crust is estimated as scaled values of the order 10−5 cm2 s−1 for helium (over 2 Gyr and 40 km vertically) versus 10−2 cm2 s−1 for heat. This rate of mass transport requires not only release of He from the solid phase via diffusion, fracturing, or comminution but also an enhanced rate of mass transport facilitated by some degree of fluid advection. This further implies a separation of heat and mass during transport which will significantly influence the interpretations of heat and 3He/4He relations.
Characteristics of infrasound from lightning and sprites near thunderstorm areas
Authors: Farges Thomas , Blanc Elisabeth
Published: June 2010

Research about thunder was mainly performed 20–30 years ago but has been renewed in recent years due to new interest about infrasound in the framework of the verification of the compliance of the Comprehensive Nuclear‐Test‐Ban Treaty. During the Eurosprite 2005 campaign, an infrasound miniarray has been set up in France to measure the characteristics of infrasound from lightning and sprites when these kinds of sources were close to the sensors (that is, for lightning distances lower than 100 km and sprite distances lower than 300 km). For two large thunderstorms which passed over the station, detection conditions of infrasound from lightning are detailed, and some characteristics are thoroughly described (e.g., amplitude variation with distance and spectrum of an individual event in the frequency range from 0.01 to 10 Hz). The locations of infrasound sources are determined using a 3‐D inversion. Infrasound signals from sprites have also been detected, and the 3‐D inversion method used for lightning infrasound has been adapted to locate the sources of infrasound from sprites. Four different sprite infrasound events are analyzed in this way. The infrasound source corresponds well to the sprite spatial characteristics deduced from camera observations. Questions about generation mechanisms of infrasound from lightning and sprites still remain. These new results should help us to understand the sound generation processes.
Morphological characterization of soot aerosol particles during LACIS Experiment in November (LExNo)
Authors: Kiselev A. , Wennrich C. , Stratmann F. , Wex H. , Henning S. , Mentel T. F. , Kiendler‐Scharr A. , Schneider J. , Walter S. , Lieberwirth I.
Published: June 2010

Combined mobility and aerodynamic measurements were used to characterize the morphology of soot particles in an experimental campaign on the hygroscopic growth and activation of an artificial biomass burning aerosol. A custom‐made, single‐stage low‐pressure impactor and two aerosol mass spectrometers (AMS) operating in the free molecular regime were used to measure the vacuum aerodynamic diameter of mobility‐selected artificial soot particles that were produced in a spark discharge generator and then modified by condensation of ammonium hydrogen sulfate or levoglucosan as a coating to change their hydroscopic activity. Transmission electron microscope images revealed a relationship between the electrical mobility diameter and the diameter of the enveloping sphere, thus enabling evaluation of the effective density of soot agglomerates. A fractal description of the morphology of the soot aggregates allowed for evaluation of the average mass of the hygroscopic material per particle. The average mass of the hygroscopic material per particle was also measured directly with the two AMS instruments, and the agreement between the two methods was found satisfactory. This tandem approach allows detection of small changes in the particle effective density and morphology caused by condensation of organic material.
Infrared reflectance spectra of particulate mixtures
Authors: Fonti S. , Montanaro S. , Politi R. , Blanco A. , Marra A. C. , Marzo G. A. , Orofino V.
Published: June 2010

In this work we report the main results of a laboratory test program aimed to check the spectral behavior of several mixtures of particulate samples. The chosen spectral interval is from 2.5 to 25.0 μm since it is the range where many minerals have their characteristic features and it is important for the interpretation of remote sensing spectra of planetary surfaces. The present study uses directional hemispherical reflectance spectra of three particulate minerals (dolomite, olivine, and quartz), with different grain sizes (ranging from 1 to 300 μm), and of their mixtures. It was found that, in the spectral range between 2.5 μm and the Christiansen feature, the reflectance of the mixtures is a nonlinear combination of the reflectance of the single pure materials, in agreement with the results found at shorter wavelength and reported in the literature. Our experimental results also confirm that, for longer wavelength, the reflectance of the mixtures is a linear combination of the reflectance of the single pure minerals. In this work, after checking some important simplifying hypotheses, we show that the mixture spectra cannot be always accurately reproduced using the volume percentage of each component, but it has a complicate behavior requiring a careful evaluation of all the parameters involved in the process. In particular we have determined experimentally the penetration depth of the radiation at different wavelengths in some of the mixtures. In this way we have been able to address the important issue of the influence of surface composition on the observed spectra.
Numerical modeling of Martian gully sediment transport: Testing the fluvial hypothesis
Authors: Parsons R. A. , Nimmo F.
Published: June 2010

Using a stereo pair of HiRISE images of a pole‐facing crater slope at 38°S, 218°E, we measure topographic profiles along nine gullies. Typical slopes of the interior channel region (above the depositional apron) are ∼20°. We test the hypothesis that sediment transport on gully slopes occurs via fluvial transport processes by developing a numerical sediment transport model based on steep flume experiments performed by Smart (1984). At 20° slopes, channels 1 m deep by 8 m wide and 0.1 m deep by 3 m wide transport a sediment volume equal to the alcove volume of 6 × 105 m3 in 10 h and 40 days, respectively, under constant flow conditions. Snowpack melting cannot produce the water discharge rates necessary for fluvial sediment transport unless long‐term (kyr) storage of the resulting meltwater occurs. If these volumes of water are discharged as groundwater, the required aquifer thicknesses and aquifer drawdown lengths would be unrealistically large for a single discharge event. More plausibly, the water volume required by the fluvial transport model could be discharged in ∼10 episodes for an aquifer 30 m thick, with a recurrence interval similar to that of Martian obliquity cycles (∼0.1 Myr).
A multiobjective response surface approach for improved water quality planning in lakes and reservoirs
Authors: Castelletti A. , Pianosi F. , Soncini‐Sessa R. , Antenucci J. P.
Published: June 2010

Improved data collection techniques as well as increasing computing power are opening up new opportunities for the development of sophisticated models that can accurately reproduce hydrodynamic and biochemical conditions of water bodies. While increasing model complexity is considered a virtue for scientific purposes, it is a definite disadvantage for management (engineering) purposes, as it limits the model applicability to what‐if analysis over a few, a priori defined interventions. In the recent past, this has become a significant limitation, particularly considering recent advances in water quality rehabilitation technologies (e.g., mixers or oxygenators) for which many design parameters have to be decided. In this paper, a novel approach toward integrating science‐oriented and engineering‐oriented models and improving water quality planning is presented. It is based on the use of a few appropriately designed simulations of a complex process‐based model to iteratively identify the multidimensional function (response surface) that maps the rehabilitation interventions into the objective function. On the basis of the response surface (RS), a greater number of interventions can be quickly evaluated and the corresponding Pareto front can be approximated. Interesting points on the front are then selected and the corresponding interventions are simulated using the original process‐based model, thus obtaining new decision‐objective samples to refine the RS approximation. The approach is demonstrated in Googong Reservoir (Australia), which is periodically affected by high concentrations of manganese and cyanobacteria. Results indicate that significant improvements could be observed by simply changing the location of the two mixers installed in 2007. Furthermore, it also suggests the best location for an additional pair of mixers.
Future of Hydrology Education Explored During EGU Town Hall Meeting
Authors: Showstack Randy
Published: June 2010

How should hydrology education adapt to deal with major environmental and other issues and to take advantage of advances in computational capabilities? What should students be learning about hydrology? And, with hydrologists having a diversity of backgrounds, interest, and training, is there such a thing as a cohesive hydrology community? These and other topics generated a provocative discussion during a 5 May town hall meeting at the European Geosciences Union (EGU) General Assembly, in Vienna, Austria.
Aircraft and Volcanic Ash a Key Focus of EGU Meeting
Authors: Showstack Randy
Published: June 2010

The erupting Eyjafjallajökull volcano in southern Iceland, which has intermittently disrupted European air traffic since 14 April, provided a dramatic backdrop for the recent European Geosciences Union (EGU) General Assembly in Vienna, Austria, about 2700 kilometers to the east. EGU organized several last‐minute conference sessions about the eruption, and a number of scientists, including some from Iceland, discussed the latest situation, monitoring and assessment needs, and new guidance about flying through volcanic ash, which volcanologist and incoming EGU president‐elect Donald Dingwell of the University of Munich, Germany, called “one of the ugliest cocktails nature throws up.”

Although the eruption was small compared with those at Mount St. Helens in 1980 or Mount Pinatubo in 1991, the event produced an estimated 0.1±0.05 cubic kilometer of tephra between 14 and 16 April, according to preliminary numbers from the Institute of Earth Sciences in Reykjavik, Iceland (see the related news item in this issue). An enormous amount of ash from the eruption got lofted into the jet stream toward the United Kingdom and the European mainland. European air traffic controllers, operating under the best guidance and guidelines available at that time—which indicated no flying in ash—shut down European air space to avoid a potential catastrophe if ash clogged up an aircraft's engines.
Kahn and Salawitch Receive 2009 Yoram J. Kaufman Award for Unselfish Cooperation in Research
Authors: Kahn Ralph A. , Salawitch Ross J.
Published: June 2010

Ralph A. Kahn and Ross J. Salawitch received the 2009 Yoram J. Kaufman Award for Unselfish Cooperation in Research at the 2009 AGU Fall Meeting, held 14–18 December in San Francisco, Calif. The award is for “broad influence in atmospheric science through exceptional creativity, inspiration of younger scientists, mentoring, international collaborations, and unselfish cooperation in research.”
Role of β2‐Adrenergic Receptor Polymorphisms on Body Weight and Body Composition Response to Energy Restriction in Obese Women: Preliminary Results
Authors: Ruiz Jonatan R , Larrarte Eider , Margareto Javier , Ares Raquel , Labayen Idoia
Published: June 2010

We investigated the role of common β2‐adrenergic receptor (ADRB2) rs1042714 (Gln27Glu) and rs1042713 (Arg16Gly) polymorphisms on body weight and body composition response to 12‐week energy‐restricted diet in women. The study comprised 78 Spanish obese (BMI: 34.0 ± 2.8 kg/m2) women (age: 36.7 ± 7 years). We measured (before and after the dietary intervention) weight and height, and BMI calculated. Moreover, body fat mass and lean mass (LM) were measured by dual energy X‐ray absorptiometry. We observed an interaction effect between the Gln27Glu polymorphism and diet‐induced changes on body weight (P = 0.006), BMI (P = 0.004), and LM (P = 0.001). Women carrying the Glu allele had a greater reduction in body weight than non‐Glu allele carriers (9.5 ± 2.9 vs. 7.0 ± 3.5%, respectively, P = 0.002). Moreover, women with the Glu allele lost more LM than the Gln27Gln group (5.9 ± 2.7 vs. 4.0 ± 2.7%, respectively, P = 0.001). We did not find any significant interaction effect between the Arg16Gly polymorphism and diet‐induced changes on the outcome variables (all P > 0.1). The results suggest that the ADRB2 Gln27Glu polymorphism has a modulating effect on diet‐induced changes on body weight and body composition, and should be considered in future obesity treatments. These findings should be taken as preliminary and be replicated in further energy restriction studies with larger sample sizes.
Proteolytic processing of the serine protease matriptase-2: identification of the cleavage sites required for its autocatalytic release from the cell surface
Authors: Stirnberg Marit , Maurer Eva , Horstmeyer Angelika , Kolp Sonja , Frank Stefan , Bald Tobias , Arenz Katharina , Janzer Andreas , Prager Kai , Wunderlich Patrick , Walter Jochen , Gütschow Michael
Published: June 2010

Matriptase-2 is a member of the TTSPs (type II transmembrane serine proteases), an emerging class of cell surface proteases involved in tissue homoeostasis and several human disorders. Matriptase-2 exhibits a domain organization similar to other TTSPs, with a cytoplasmic N-terminus, a transmembrane domain and an extracellular C-terminus containing the non-catalytic stem region and the protease domain. To gain further insight into the biochemical functions of matriptase-2, we characterized the subcellular localization of the monomeric and multimeric form and identified cell surface shedding as a defining point in its proteolytic processing. Using HEK (human embryonic kidney)-293 cells, stably transfected with cDNA encoding human matriptase-2, we demonstrate a cell membrane localization for the inactive single-chain zymogen. Membrane-associated matriptase-2 is highly N-glycosylated and occurs in monomeric, as well as multimeric, forms covalently linked by disulfide bonds. Furthermore, matriptase-2 undergoes shedding into the conditioned medium as an activated two-chain form containing the catalytic domain, which is cleaved at the canonical activation motif, but is linked to a released portion of the stem region via a conserved disulfide bond. Cleavage sites were identified by MS, sequencing and mutational analysis. Interestingly, cell surface shedding and activation of a matriptase-2 variant bearing a mutation at the active-site serine residue is dependent on the catalytic activity of co-expressed or co-incubated wild-type matriptase-2, indicating a transactivation and trans-shedding mechanism.
The obese healthy paradox: is inflammation the answer?
Authors: Barbarroja Nuria , López-Pedrera Rosario , Mayas Maria Dolores , García-Fuentes Eduardo , Garrido-Sánchez Lourdes , Macías-González M. , El Bekay Rajaa , Vidal-Puig Antonio , Tinahones Francisco J.
Published: June 2010

A paradoxical but common finding in the obesity clinic is the identification of individuals who can be considered ‘inappropriately’ healthy for their degree of obesity. We think that studying these obese but metabolically healthy individuals and comparing them with equally obese but insulin-resistant individuals could provide important insights into the mechanistic link between adipose tissue expansion and associated metabolic alterations. In the present study, we investigated whether there are differences in inflammatory and insulin signalling pathways in VAT (visceral adipose tissue) that could account for the metabolic differences exhibited by morbidly obese individuals who are either insulin-resistant (IR-MO) or paradoxically insulin-sensitive (NIR-MO). Our results indicate that there are pathways common to obesity and unrelated to insulin resistance and others that are discriminative for insulin resistance for a similar degree of obesity. For instance, all morbidly obese patients, irrespective of their insulin resistance, showed increased expression of TNFα (tumour necrosis factor α) and activation of JNK1/2 (c-Jun N-terminal kinase 1/2). However, the IR-MO group showed significantly elevated expression levels of IL (interleukin)-1β and IL-6 and increased macrophage infiltrates compared with non-obese individuals and NIR-MO. IκBα [inhibitor of NF-κB (nuclear factor κB) α], the activation of ERK1/2 (extracellular-signal-regulated kinase 1/2) and NF-κB were discriminative of the state of insulin resistance and correlated with differential changes in IRS-1 (insulin receptor substrate 1) expression and Akt activation between IR-MO and NIR-MO individuals. Our results support the concept that NIR-MO individuals lack the inflammatory response that characterizes the IR-MO patient and that IL-6, IL-1β, ERK and NF-κB are important effectors that mediate the inflammation effects promoting insulin resistance.
Age‐related association of rDNA and telomeres with the nuclear matrix in mouse hepatocytes
Authors: Moraes Alberto S. , Mondin Mateus , Beletti Marcelo E. , Aguiar‐Perecin Margarida LR , Guaraldo Ana MA , Mello Maria Luiza S.
Published: June 2010

Transcribed sequences have been suggested to be associated with the nuclear matrix, differing from non‐transcribing sequences, which have been reported to be contained in DNA loops. However, although a dozen of genes have their expression level affected by aging, data on chromatin–nuclear matrix interactions under this physiological condition are still scarce. In the present study, liver imprints from young, adult and old mice were subjected to FISH (fluorescence in situ hybridization) for 45S rDNA and telomeric sequences, with or without a lysis treatment to produce extended chromatin fibres. There was an increased amount of 45S rDNA sequences located in DNA loops as the animals grow older, while telomeric sequences were always observed in DNA loops irrespective of the animal age. We assume that active rRNA genes associate with the nuclear matrix, while DNA loops contain silent sequences. Transcription of each 45S rDNA repeat unit is suggested to be dependent on its interaction with the nuclear matrix.
Regulation of subcutaneous adipose tissue blood flow is related to measures of vascular and autonomic function
Authors: Funada Jun-ichi , Dennis A. Louise , Roberts Rachel , Karpe Fredrik , Frayn Keith N.
Published: June 2010

Appropriate blood vessel function is important to cardiovascular health. Adipose tissue plays an important role in metabolic homoeostasis, and subcutaneous abdominal ATBF (adipose tissue blood flow) is responsive to nutritional stimuli. This response is impaired in obesity, suggesting parallels with endothelial function. In the present study, we assessed whether regulation of ATBF is related to the regulation of endothelial function, assessed by FMD (flow-mediated vasodilatation) of the brachial artery. Impaired FMD is a marker of atherosclerotic risk, so we also assessed relationships between ATBF and a marker of atherosclerosis, common carotid artery IMT (intima-media thickness). As ATBF is responsive to sympatho-adrenal stimuli, we also investigated relationships with HRV (heart rate variability). A total of 79 healthy volunteers (44 female) were studied after fasting and after ingestion of 75 g of glucose. FMD, fasting ATBF and the responsiveness of ATBF to glucose were all negatively related to BMI (body mass index), confirming the adverse cardiovascular effects of adiposity. FMD was related to fasting ATBF (rs=0.32, P=0.008) and, at least in males, this relationship was independent of BMI (P=0.02). Common carotid artery IMT, measured in a subset of participants, was negatively related to fasting ATBF [rs=−0.51, P=0.02 (n=20)]. On the other hand, ATBF responsiveness to glucose had no relationship with either FMD or IMT. In multiple regression models, both fasting and stimulated ATBF had relationships with HRV. In conclusion, our results show that the regulation of ATBF has features in common with endothelial function, but also relationships with autonomic cardiovascular control as reflected in HRV.
High-Pressure Calibration: A Critical Review
Authors: Decker D. L. , Bassett W. A. , Merrill L. , Hall H. T. , Barnett J. D.
Published: June 2010

A critical review of experimental technique for measuring high pressures has been made. The broad coverage includes discussions relating to (a) the establishment of a primary pressure scale using the free-piston gage, (b) the selection and precise measurement of identifiable phase changes as fixed pressure points, and (c) the use of interpolation and extrapolation techniques such as resistance gages, equations of state, and optical changes. The emphasis is on static pressure measurements above 10 kbar, but shock measurements are also considered for completeness. The pressure values to be associated with the fixed points have been analyzed in detail. Temperature measurement in the high pressure environment is also reviewed. The accuracy with which pressures can be measured has been carefully considered; the maximum accuracies now obtainable are considered to be of the order of 0.02 percent at 8 kbar, 0.25 percent at 25 kbar, 2 percent at 50 kbar, and 4 percent at 100 kbar.
The Surface Tension of Pure Liquid Compounds
Authors: Jasper Joseph J.
Published: June 2010

The surface tension tables presented herein are the result of a literature survey, evaluation, and compilation of data of some 2200 pure liquid compounds, 226 of which were reported for a single temperature. These are arranged with related compounds in the increasing order of their molecular weights. As far as possible the method of measurement, nature of atmosphere to which the liquid was exposed during measurements, and the estimated accuracy are given for each liquid. The tabulated values were calculated from the derived results of directly measured quantities reported in the literature of many countries from about 1874 to 1969. Preliminary plots of the experimentally measured quantities indicated that the surface tensions of the liquid compounds are linear functions of the temperature over the reported operational range. The principle of least squares was applied to experimental surface tension values to establish the regression curves and their equations. The constants of the equations (slope and intercept), together with the standard deviations are given for each compound. The selection factors establishing criteria of quality of surface tension data are discussed. These include (a) method of measurement, (b) purity of compound, (c) quality of apparatus and assembly, (d) experimental procedure (experimentation), (e) reliability of measurements (most probable values), (f) experience of investigator, and (g) availability of data. There are 274 references listed alphabetically.
Compilation of Energy Band Gaps in Elemental and Binary Compound Semiconductors and Insulators
Authors: Strehlow W. H. , Cook E. L.
Published: June 2010

Energy band gaps are tabulated for elemental and binary compound semiconductors and insulators reported in 723 references. The method of measurement, transition, type of sample, and other pertinent information are included for each entry. The determinations believed to be the most reliable are indicated.
Quantum confinement effects in Si/Ge heterostructures with spatially ordered arrays of self-assembled quantum dots
Authors: Agafonov Oleksiy B. , Dais Christian , Grützmacher Detlev , Haug Rolf J.
Published: June 2010

Magnetotunneling spectroscopy was employed to probe the confinement in vertical Si/Ge double-barrier resonant tunneling diodes with regularly distributed Ge quantum dots. Their current-voltage characteristics reveal a steplike behavior in the vicinity of zero bias, indicating resonant tunneling of heavy-holes via three-dimensionally confined unoccupied hole states in Ge quantum dots. Assuming parabolic confinement, we extract the strength of the confinement potential of quantum dots.
Chirped pulse shadowgraphy for single shot time resolved plasma expansion measurements
Authors: Prasad Y. B. S. R. , Barnwal S. , Naik P. A. , Chakera J. A. , Khan R. A. , Gupta P. D.
Published: June 2010

The dynamics of ultrashort laser plasmas demand single shot temporal measurements on fast time scales. We describe a method to record the plasma expansion on picosecond (ps) timescales continuously over hundreds of ps, in single shot. The method uses the chirp of a Ti:sapphire laser as a time-resolved optical diagnostic tool. Using this technique, the evolution of the plasma expansion had been recorded with ps time resolutions, by probing with a chirped laser pulse of 200 ps duration. A peak expansion velocity of 1.8×107 cm/s is observed and its evolution in time is obtained for ∼300 ps.
Temperature effects on metal-alumina-nitride-oxide-silicon memory operations
Authors: Padovani Andrea , Larcher Luca , Heh Dawei , Bersuker Gennadi , Della Marca Vincenzo , Pavan Paolo
Published: June 2010

We present a detailed investigation of temperature effects on the operation of TaN/Al2O3/Si3N4/SiO2/Si (TANOS) memory devices. We show that not only retention but also program and erase operations are affected significantly by temperature. Using a large set of experimental data and simulations on a variety of TANOS stacks, we show that the temperature dependence of TANOS program and erase operations can be explained by accounting for that the alumina dielectric constant increases by 20%–25% over a 125 K temperature range.
Band structure measurement of organic single crystal with angle-resolved photoemission
Authors: Ding Huanjun , Reese Colin , Mäkinen Antti J. , Bao Zhenan , Gao Yongli
Published: June 2010

The electronic structure of bulk rubrene single crystal was studied with angle-resolved photoemission spectroscopy. Highly reproducible dispersive features were observed with nice symmetry about the Brillouin zone center and boundaries, representing the band structure measured for a bulk organic single crystal. The high quality of the surface was confirmed with scanning tunneling microscopy. The energy dispersion of the highest occupied molecular orbitals derived bands showed strong anisotropic behavior in the a-b plane of the unit cell. The measured band structure, however, differs unexpectedly from theoretical calculations in terms of the amount of the dispersion and the separation of the bands.
A critical review of the Stark widths and shifts of spectral lines from non-hydrogenic atoms
Authors: Konjevic N. , Roberts J. R.
Published: June 2010

A critical review of all available data on the Stark broadening and shifts of spectral lines of neutral elements has been undertaken. Over 200 papers compiled by the NBS Data Center on Atomic Line Shapes and Shifts have been evaluated, and of these, 68 were chosen as having reviewable data. Only those papers with properly determined critical factors, such as electron density, temperature, spatial homogeneity, optical depth, and instrument function deconvolution, were selected.
Survey of superconductive materials and critical evaluation of selected properties
Authors: Roberts B. W.
Published: June 2010

This publication includes all data on superconductive materials intercepted through March 1975. Data on the bulk elements have been critically evaluated, and values on alloys, compounds, and other forms have been selected and condensed to indicate the probable value and spread of values observed. Proven non-superconductors have been noted. Conflict in data values has been noted. All data have been keyed to the literature in one or more of the tables. Special subdivisions are presented for superconductive materials with organic constituents and for those based on semiconductive materials. The properties presented are superconductive critical temperature, critical magnetic fields, material state and composition including crystal-structure type where noted, a key to thin-film forms, and the presence of thermodynamic data (generally the electronic specific heat, γ, and Debye ϑ). High-magnetic-field superconductors are noted with listing of Hc1, Hc, Hc2, and Hc3 plus the temperature of observation Tobs.
Nuclear Spins and Moments
Authors: Fuller Gladys H.
Published: June 2010

A summary of nuclear-moment values and an index, arranged by Z and A is presented. The summary value is based on the experimentally determined values of the nuclear moments which have been listed in tables according to the techniques used. Each table is preceded by a short introduction describing the experimental technique involved and the method of calculating the moment from the measured quantities. References are given for all data quoted. The date for the last systematic literature search is included with each table. This tabulation supplements and revises the earlier tables which appeared in Nuclear Data Tables, Volume A5, 433−612(1969).
Heat Capacity and Other Thermodynamic Properties of Linear Macromolecules. V. Polystyrene
Authors: Gaur Umesh , Wunderlich Bernhard
Published: June 2010

The heat capacity of polystyrene from 0 K to 600 K is reviewed on the basis of measurements on 29 samples reported in the literature. A set of recommended data for amorphous polystyrene is derived. The effect of tacticity on the heat capacity is also evaluated. Entropy and enthalpy functions are calculated. This paper is the fifth in a series of publications which will ultimately cover all heat capacity measurements on linear macromolecules.
Spectroscopy and Structure of the Lithium Hydride Diatomic Molecules and Ions
Authors: Stwalley William C. , Zemke Warren T.
Published: June 2010

All significant experimental measurements and many theoretical calculations of the spectroscopy and structure of the isotopic lithium hydrides ( 6LiH, 7LiH, 6LiD, 7LiD) are identified and reviewed. Published molecular constant determinations from conventional and laser spectroscopy are evaluated; recommended spectroscopic constants for the X  1Σ+, A  1Σ+, and B  1Π states are tabulated. Potential energy curves (RKR, IPA, and hybrid) for the X  1Σ+, A  1Σ+, and B  1Π states are evaluated and recommended curves are tabulated. Dissociation energy estimates are evaluated and recommended D0 and De values tabulated for X  1Σ+, A  1Σ+, and B 1Π states. Accurate electronic structure calculations (Hartree Fock or better) on this ‘‘workbench of theoretical chemistry’’ are listed and described briefly; all excited electronic states considered are included. Experimental and theoretical radiative and dipole properties are noted and discussed. Adiabatic corrections to the Born–Oppenheimer approximation are also reviewed. Calculations on LiH+ and LiH− are also listed and described briefly.
Thermodynamic Properties of Alkali Metal Hydroxides. Part 1. Lithium and Sodium Hydroxides
Authors: Gurvich L. V. , Bergman G. A. , Gorokhov L. N. , Iorish V. S. , Leonidov V. Ya. , Yungman V. S.
Published: June 2010

The data on thermodynamic and molecular properties of the lithium and sodium hydroxides have been collected, critically reviewed, analyzed, and evaluated. Tables of thermodynamic properties (C°p,Φ°=−(G°−H°(0)/T, S°, H°−H°(0), ΔfH°, ΔfG°) of these hydroxides in the condensed and gaseous states have been calculated using the results of the analysis and some estimated values. The recommendations are compared with earlier evaluations given in the JANAF Thermochemical Tables and Thermodynamic Properties of Individual Substances. The properties considered are: the temperature and enthalpy of phase transitions and fusion, heat capacities, spectroscopic data, structures, bond energies, and enthalpies of formation at 298.15 K. The thermodynamic functions in solid, liquid, and gaseous states are calculated from T=0 to 2000 K for substances in condensed phase and up to 6000 K for gases.
Ternus Effect: Two Processes or Differential Activation? Comments on Odic and Pratt's 2008 Paper
Authors: Petersik J Timothy
Published: June 2010

Using a bistable apparent-motion display, Odic and Pratt (2008, Perception37 1790–1804) have recently presented data that they interpret as being inconsistent with what they call “the two-process theory”. Instead, they argue, their data can be explained by the differential-activation theory along with a process they identify as “temporal summation of contrast”. It is argued here that Odic and Pratt misinterpreted the two-process distinction and used a display that was too unusual to be adequately addressed by it. Further, their use of the differential-activation theory and, in particular, the temporal summation of contrast, seems problematic. It is concluded that there is little in their data and theoretical interpretation to justify rejection of the two-process approach.
Differential-Activation Theory Can Account for the Ternus Display: Rejoinder to Petersik
Authors: Odic Darko , Pratt Jay
Published: June 2010

The Ternus display is a bistable apparent-motion display that has captivated researchers for decades. Recently, Odic and Pratt (2008, Perception37 1790–1804) provided evidence against the well-known two-process theory of Braddick and Adlard [1978, Visual Psychophysics and Physiology (New York: Academic Press) pp 417–426] and provided an explanatory framework using the differential-activation theory of Gilroy et al (2001, Perception & Psychophysics63 847–861). A comment by Petersik (this issue) challenges the methodology and theoretical implications of Odic and Pratt, and claims that the two-process distinction still has a role to play in the Ternus display. In this rejoinder, we examine the main points made by Petersik and expand on the differential-activation theory and its applicability to the Ternus display.
Force-dependent polymorphism in type IV pili reveals hidden epitopes
Authors: Biais Nicolas , Higashi Dustin L. , Brujić Jasna , So Magdalene , Sheetz Michael P.
Published: June 2010

Through evolution, nature has produced exquisite nanometric structures, with features unrealized in the most advanced man-made devices. Type IV pili (Tfp) represent such a structure: 6-nm-wide retractable filamentous appendages found in many bacteria, including human pathogens. Whereas the structure of
Neisseria gonorrhoeae
Tfp has been defined by conventional structural techniques, it remains difficult to explain the wide spectrum of functions associated with Tfp. Here we uncover a previously undescribed force-induced quaternary structure of the
N. gonorrhoeae
Tfp. By using a combination of optical and magnetic tweezers, atomic force microscopy, and molecular combing to apply forces on purified Tfp, we demonstrate that Tfp subjected to approximately 100 pN of force will transition into a new conformation. The new structure is roughly 3 times longer and 40% narrower than the original structure. Upon release of the force, the Tfp fiber regains its original form, indicating a reversible transition. Equally important, we show that the force-induced conformation exposes hidden epitopes previously buried in the Tfp fiber. We postulate that this transition provides a means for
N. gonorrhoeae
to maintain attachment to its host while withstanding intermittent forces encountered in the environment. Our findings demonstrate the need to reassess our understanding of Tfp dynamics and functions. They could also explain the structural diversity of other helical polymers while presenting a unique mechanism for polymer elongation and exemplifying the extreme structural plasticity of biological polymers.