bluuebunny/crossref_metadata_2025_split huggingface dataset:
High fluid pressures and high fluid flow rates in the Megasplay Fault Zone, NanTroSEIZE Kumano Transect, SW Japan
Authors: Moore J. Casey , Barrett Myles , Thu Moe Kyaw 
Published: August 2012

Annular pressure while drilling data shows high fluid overpressures at Site C0001 in part of the megasplay fault zone of the NanTroSEIZE transect across the subduction zone of SW Japan. Mostly standard annular pressures while drilling occur at three other sites, including two penetrating major faults. The two holes at Site C0001 show a step up to lithostatic annular pressure at about 500 mbsf, following initial indicators of overpressure at about 375 mbsf (meters below seafloor). The annular pressure remains high and increasing to total depth of 1000 mbsf. Seismic lines through the site show bright reflectors in the zone of initial annular pressure increase. Borehole images, sonic velocities, and resistivity all suggest a zone of fractures, from about 490 to 630 mbsf. A hydraulic model of the fluid system explains the observed pressures by influx of formation fluid at about 500 mbsf. The combination of a natural influx of 3300 l/m plus 2200 l/m from the drilling system can explain the observed annular pressures. The highly fractured zone that bleeds fluids to the borehole may be sealed by a localized zone of compressive stress or by overlying gas hydrates.
Evidence of sudden rupture of a large asperity during the 2008 Mw7.9 Wenchuan earthquake based on strong motion analysis
Authors: Zhang Guohong , Vallée Martin , Shan Xinjian , Delouis Bertrand 
Published: August 2012

We investigate the rupture process of the 12 May 2008 Wenchuan earthquake using the records of 26 strong‐motion stations, located 20–120 km from the seismic fault and with a good azimuthal coverage. The wave velocity model required to conduct this analysis has been validated against aftershocks, for which the point source hypothesis is a very good approximation. The inversion of the main shock rupture process confirms the slip distribution and the average rupture velocity (∼3 km/s) previously determined. However, a very peculiar behavior is clearly resolved by the extensive data set used in this study: the major slip area of the Wenchuan earthquake, located at 20–50 km North‐East of the epicenter, is shown to break almost simultaneously, 25 s after earthquake initiation. This implies that slip in this part of the fault cannot be understood by simple stress release at the rupture front. A more likely interpretation is the presence of a strong asperity, which could break only when it was completely surrounded by stress increase, resulting in a delayed but brutal rupture.
Space‐based observations of megacity carbon dioxide
Authors: Kort Eric A. , Frankenberg Christian , Miller Charles E. , Oda Tom 
Published: August 2012

Urban areas now house more than half the world's population, and are estimated to contribute over 70% of global energy‐related CO2emissions. Many cities have emission reduction policies in place, but lack objective, observation‐based methods for verifying their outcomes. Here we demonstrate the potential of satellite‐borne instruments to provide accurate global monitoring of megacity CO2 emissions using GOSAT observations of column averaged CO2 dry air mole fraction (XCO2) collected over Los Angeles and Mumbai. By differencing observations over the megacity with those in nearby background, we observe robust, statistically significant XCO2 enhancements of 3.2 ± 1.5 ppm for Los Angeles and 2.4 ± 1.2 ppm for Mumbai, and find these enhancements can be exploited to track anthropogenic emission trends over time. We estimate that XCO2 changes as small as 0.7 ppm in Los Angeles, corresponding to a 22% change in emissions, could be detected with GOSAT at the 95% confidence level.
Charge moment change and lightning‐driven electric fields associated with negative sprites and halos
Authors: Li Jingbo , Cummer Steven , Lu Gaopeng , Zigoneanu Lucian 
Published: August 2012

Sprites are structured high altitude optical emissions produced by lightning‐driven electric fields. Both strong positive and negative cloud to ground flashes (CGs) are capable of initiating sprites. However, reported sprites are almost exclusively produced by +CGs. The very limited number of negative polarity sprites makes it difficult to reveal their morphologies and mechanisms. Since 2008, we have operated low light cameras at 5 locations in the United States to detect lightning‐driven transient luminous events (TLEs). At Duke University, two pairs of magnetic sensors simultaneously record lightning‐radiated magnetic fields. During 4 years of observations, the low light cameras collectively captured 1651 sprite events. Among them, 6 were produced by −CG lightning, which was confirmed by both the National Lightning Detection Network (NLDN) and magnetic field measurements. All of these negative sprites show similar features in their morphology, lightning source current, and lightning‐driven ambient electric fields. They all initiate within a few ms from their parent lightning discharges and always are accompanied by sprite halos. Compared to positive sprites, the downward streamers in negative sprites terminate at higher altitudes, about 55–60 km. The extracted source current of their parent lightning discharges is very impulsive and produces at least 450 C km charge moment change in 0.5 ms or less. Unlike most +CG strokes, essentially no continuing current follows these −CGs. Thus the uniformity of negative sprite morphology appears to reflect the uniformity of the characteristics of high charge transfer negative strokes. Numerical simulation shows these impulsive source currents produce very high (>2 Ek, where Ek is the local air breakdown field) but short‐lived electric fields at halo altitudes between 70 km and 90 km. At streamer termination altitudes, the inferred background electric field is 0.2–0.3 Ek, which is close to but below the critical field (0.4 Ek) for negative streamer propagation. The simulations also show that the timescale of the lightning source current has a significant impact on the high altitude electric fields and thus the sprite initiation and morphology. With the same amount of charge transfer, a more impulsive current source produces a higher electric field of shorter duration at halo and sprite altitudes. The short timescales may explain why a larger threshold of total charge moment change is required to initiate negative sprites than short‐delayed positive sprites, whose parent lightning source current is usually less impulsive.
Evolution of equatorial irregularities under varying electrodynamical conditions: A multitechnique case study from Indian longitude zone
Authors: Hajra R. , Chakraborty S. K. , Mazumdar S. , Alex S. 
Published: August 2012

A comprehensive multitechnique study on the postsunset evolutions of equatorial ionization anomaly (EIA) and equatorial plasma density irregularities in the context of the varying electrodynamical conditions under normal equatorial electrojet (EEJ), complete and partial counter electrojet (CEJ) events is presented from the Indian longitude zone. The study involves analysis of scintillation data at VHF (250 MHz) and GPS L1 (1575.42 MHz) frequency, ionosonde data, magnetometer data along with global ionospheric maps (GIMs) of total electron content (TEC) for the vernal equinoctial months (March–April) of 2011. The investigation reveals inefficiency of the noontime peak EEJ to dictate the day‐to‐day variability of postsunset irregularity phenomena. Intensification of EEJ after ∼1530 IST (Indian standard time) on normal EEJ days and significantly enhanced residual fields presumably due to CEJ event after ∼1700 IST on complete and partial CEJ days are found to be associated with the resurgence of EIA and evolution of postsunset irregularities. The results are discussed in terms of superposition effects of electric fields arising from E‐ and F‐ region dynamos.
Very‐low‐frequency saucers observed on DEMETER
Authors: James H. G. , Parrot M. , Berthelier J.‐J. 
Published: August 2012

Observations of very‐low‐frequency saucers by the electric field instrument (Instrument Champ Electrique, ICE) aboard the DEMETER spacecraft have added new evidence about the nature of the highly localized source of this radiation. DEMETER orbited sun‐synchronously at altitudes around 660 km, significantly below those at which earlier spacecraft detected saucers. Also, DEMETER data establish the existence of saucer sources in the dayside ionosphere. Frequency‐time slopes of saucers in DEMETER spectrograms have been analyzed with two‐dimensional ray tracing. To produce such slopes requires long vertical separations between the source and the spacecraft, in some cases much greater than the height of the spacecraft above ground. It is concluded that the sources lie above the satellite and radiate downward. Bidirectional radiation patterns and the broadband quasielectrostatic whistler mode energy spectrum are consistent with the published results of simulations of nonlinear two‐stream instabilities.
Variability of Indonesian throughflow within Makassar Strait, 2004–2009
Authors: Susanto R. Dwi , Ffield Amy , Gordon Arnold L. , Adi T. Rameyo 
Published: August 2012

In contrast to earlier measurements, January 2004 through May 2009 Makassar Strait velocities within the main Pacific inflow pathway of the Indonesian throughflow (ITF) are larger with a clear signal of the Asian‐Australian monsoon overriding the relatively weak 2006/2007 El Niño and 2007/2008 La Niña. The Makassar flow is thermocline intensified with maximum along‐channel velocity of −0.8 m/s near 120 m during the southeast monsoon, July to September, decreasing to −0.6 m/s from October to December, during the transition to the northwest monsoon. The temperature variability is highly correlated to ENSO, and the salinity variability reveals low‐salinity surface water inputs to the ITF, possibly from the Java and Sulu seas. Empirical Orthogonal Function (EOF) analysis of the velocity profile reveals that the first mode (45%) is dominated by the intrusions of Kelvin waves from the south, the second mode (30%) reflects ENSO modulation, and the third mode (17%) is associated with regional monsoon winds. The strength of the northward intrusions of Kelvin waves plays an important role in the total transport. The 2004–2009 average seasonal transport varied from −15.5 Sv (Sv = 106 m3/s) during the northwest monsoon (January to March) to −9.6 Sv during the monsoon transition (October to December). The annual mean transport is southward at 13.3 ± 3.6 Sv, with small year‐to‐year range from 12.5 to 14.0 Sv, substantially higher than measurements from 1997 when El Niño suppressed the transport (9.2 Sv).
Is the deep Indian Ocean MOC sustained by breaking internal waves?
Authors: Huussen T. N. , Naveira‐Garabato A. C. , Bryden H. L. , McDonagh E. L. 
Published: August 2012

The Indian Ocean hosts a vigorous basin‐scale overturning that constitutes one of the major deep upwelling branches of the global meridional overturning circulation (MOC). The extent to which the deep Indian Ocean MOC is sustained by breaking internal waves is assessed by quantifying and comparing the energetics of the overturning and those of the regional internal wave field. A range of published inverse estimates of the circulation across 32°S is used to assess the basin average buoyancy fluxes. The turbulent dissipation needed to sustain the MOC ranges between 0.17 ± 0.04 and 1.19 ± 0.17 TW, which is consistent with the estimated 0.35−0.26+1.04 TW dissipated by breaking internal waves, as inferred from observed fine structure. Both estimates of turbulent dissipation are consistent with the total energy input into the regional internal wave field (0.21−0.05+0.08TW) based on published estimates of energy conversion from winds, tides and geostrophic bottom flows. However, a discrepancy arises when comparing the energetics at different density levels. At mid‐ocean density levels (∼1000–3000 m) the dissipation of internal wave energy is found to be significantly smaller (factor 5–10) than the dissipation needed to sustain inverse estimates of the MOC. The uncertainty related to undersampling of internal wave breaking hot spots was analyzed and found to be small, which suggests that mixing processes other than wave breaking due to weak wave‐wave interactions, may be significant in the deep Indian Ocean.
Regional‐scale phenology modeling based on meteorological records and remote sensing observations
Authors: Yang Xi , Mustard John F. , Tang Jianwu , Xu Hong 
Published: August 2012

Changes of vegetation phenology in response to climate change in the temperate forests have been well documented recently and have important implications on the regional and global carbon and water cycles. Predicting the impact of changing phenology on terrestrial ecosystems requires an accurate phenology model. Although species‐level phenology models have been tested using a small number of vegetation species, they are rarely examined at the regional level. In this study, we used remotely sensed phenology and meteorological data to parameterize the species‐level phenology models. We used a remotely sensed vegetation index (Two‐band Enhanced Vegetation Index, EVI2) derived from the Moderate Resolution Spectroradiometer (MODIS) 8‐day reflectance product from 2000 to 2010 of New England, United States to calculate remotely sensed vegetation phenology (start/end of season, or SOS/EOS). The SOS/EOS and the daily mean air temperature data from weather stations were used to parameterize three budburst models and one senescence model. We compared the relative strengths of the models to predict vegetation phenology and selected the best model to reconstruct the “landscape phenology” in New England from year 1960 to 2010. Of the three budburst models tested, the spring warming model showed the best performance with an averaged Root Mean Square Deviation (RMSD) of 4.59 days. The Akaike Information Criterion supported the spring warming model in all the weather stations. For senescence modeling, the Delpierre model was better than a null model (the averaged phenology of each weather station, averaged model efficiency = 0.33) and has a RMSD of 8.05 days. A retrospective analysis using the spring warming model suggests a statistically significant advance of SOS in New England from 1960 to 2010 averaged as 0.143 days per year (p = 0.015). EOS calculated using the Delpierre model and growing season length showed no statistically significant advance or delay between 1960 and 2010 in this region. These results suggest the applicability of species‐level phenology models at the regional level (and potentially terrestrial biosphere models) and the feasibility of using these models in reconstructing and predicting vegetation phenology.
Regulation of hepatic insulin sensitivity by activating signal co-integrator-2
Authors: Kim Geun Hyang , Lee Kyung Jin , Oh Gyun-Sik , Yoon Jin , Kim Hae Won , Kim Seung-Whan 
Published: August 2012

ASC-2 (activating signal co-integrator-2, also known as AIB3 and NCoA6) is a transcriptional co-activator and regulates insulin secretion and β-cell survival. The present study was performed to elucidate the role of ASC-2 in the regulation of insulin sensitivity. Although islet cells from 10-week-old ASC-2+/− mice secreted less insulin than wild-type islets, there was no significant difference in glucose tolerance between ASC-2+/− and wild-type mice. However, ASC-2+/− mice did show increased insulin sensitivity compared with wild-type mice in insulin tolerance tests. Consistently, the levels of phosphorylated Akt were higher in ASC-2+/− hepatocytes than in wild-type hepatocytes after insulin treatment. Moreover, decreases in phosphoenol pyruvate carboxykinase mRNA in refed mice were more prominent in ASC-2+/− livers than in wild-type livers. Interestingly, the expression levels of SOCS1 (suppressor of cytokine signalling 1) and SOCS3, well-known insulin signalling inhibitors, were decreased in ASC-2+/− hepatocytes and increased in ASC-2-overexpressing hepatocytes. Furthermore, ASC-2 was recruited to the promoter region of SOCS1 and potentiated the transcription by SREBP-1c (sterol-regulatory-element-binding protein-1c). This transcription-activating function of ASC-2 was diminished by mutations of SREBP-1c-binding sites in the SOCS1 promoter. Taken together, these results suggest that ASC-2 negatively affects hepatic insulin sensitivity, at least in part, through induction of the insulin signalling inhibitors SOCS1 and SOCS3.
Reliability issues for a bolometer detector for ITER at high operating temperatures
Authors: Meister H. , Kannamüller M. , Koll J. , Pathak A. , Penzel F. , Trautmann T. , Detemple P. , Schmitt S. , Langer H. 
Published: August 2012

The first detector prototypes for the ITER bolometer diagnostic featuring a 12.5 μm thick Pt-absorber have been realized and characterized in laboratory tests. The results show linear dependencies of the calibration parameters and are in line with measurements of prototypes with thinner absorbers. However, thermal cycling tests up to 450 °C of the prototypes with thick absorbers demonstrated that their reliability at these elevated operating temperatures is not yet sufficient. Profilometer measurements showed a deflection of the membrane hinting to stresses due to the deposition processes of the absorber. Finite element analysis (FEA) managed to reproduce the deflection and identified the highest stresses in the membrane in the region around the corners of the absorber. FEA was further used to identify changes in the geometry of the absorber with a positive impact on the intrinsic stresses of the membrane. However, further improvements are still necessary.
Structures of dolomite at ultrahigh pressure and their influence on the deep carbon cycle
Authors: Merlini Marco , Crichton Wilson A. , Hanfland Michael , Gemmi Mauro , Müller Harald , Kupenko Ilya , Dubrovinsky Leonid 
Published: August 2012

Carbon-bearing solids, fluids, and melts in the Earth's deep interior may play an important role in the long-term carbon cycle. Here we apply synchrotron X-ray single crystal micro-diffraction techniques to identify and characterize the high-pressure polymorphs of dolomite. Dolomite-II, observed above 17 GPa, is triclinic, and its structure is topologically related to CaCO
3
-II. It transforms above 35 GPa to dolomite-III, also triclinic, which features carbon in [3 + 1] coordination at the highest pressures investigated (60 GPa). The structure is therefore representative of an intermediate between the low-pressure carbonates and the predicted ultra-high pressure carbonates, with carbon in tetrahedral coordination. Dolomite-III does not decompose up to the melting point (2,600 K at 43 GPa) and its thermodynamic stability demonstrates that this complex phase can transport carbon to depths of at least up to 1,700 km. Dolomite-III, therefore, is a likely occurring phase in areas containing recycled crustal slabs, which are more oxidized and Ca-enriched than the primitive lower mantle. Indeed, these phases may play an important role as carbon carriers in the whole mantle carbon cycling. As such, they are expected to participate in the fundamental petrological processes which, through carbon-bearing fluids and carbonate melts, will return carbon back to the Earth’s surface.
A quantitative version of the commutator theorem for zero trace matrices
Authors: Johnson William B. , Ozawa Narutaka , Schechtman Gideon 
Published: August 2012

Let
A
be an
m
×
m
complex matrix with zero trace and let
ε
> 0. Then there are
m
×
m
matrices
B
and
C
such that
A
= [
B
,
C
] and ‖
B
‖‖
C
‖ ≤
K

ε

m

ε

‖
A
‖ where
K

ε

depends only on
ε
. Moreover, the matrix
B
can be taken to be normal.
A search for thermal excursions from ancient extraterrestrial impacts using Hadean zircon Ti-U-Th-Pb depth profiles
Authors: Abbott Sunshine S. , Harrison T. Mark , Schmitt Axel K. , Mojzsis Stephen J. 
Published: August 2012

Few terrestrial localities preserve more than a trace lithic record prior toca.3.8 Ga greatly limiting our understanding of the first 700 Ma of Earth history, a period inferred to have included a spike in the bolide flux to the inner solar system atca.3.85–3.95 Ga (the Late Heavy Bombardment, LHB). An accessible record of this era may be found in Hadean detrital zircons from the Jack Hills, Western Australia, in the form of μm-scale epitaxial overgrowths. By comparing crystallization temperatures of pre-3.8 Ga zircon overgrowths to the archive of zircon temperature spectra, it should, in principle, be possible to identify a distinctive impact signature. We have developed Ti-U-Th-Pb ion microprobe depth profiling to obtain age and temperature information within these zircon overgrowths and undertaken a feasibility study of its possible use in identifying impact events. Of eight grains profiled in this fashion, four have overgrowths of LHB-era age. Age vs. temperature profiles reveal a period betweenca.3.85–3.95 Ga (i.e., LHB era) characterized by significantly higher temperatures (approximately 840–875 °C) than do older or younger zircons or zircon domains (approximately 630–750 °C). However, temperatures approaching 900 °C can result in Pb isotopic exchange rendering interpretation of these profiles nonunique. Coupled age-temperature depth profiling shows promise in this role, and the preliminary data we report could represent the first terrestrial evidence for impact-related heating during the LHB.
Kinetic mechanism of p53 oncogenic mutant aggregation and its inhibition
Authors: Wilcken Rainer , Wang GuoZhen , Boeckler Frank M. , Fersht Alan R. 
Published: August 2012

Aggregation of destabilized mutants of the tumor suppressor p53 is a major route for its loss of activity. In order to assay drugs that inhibit aggregation of p53, we established the basic kinetics of aggregation of its core domain, using the mutant Y220C that has a mutation-induced, druggable cavity. Aggregation monitored by light scattering followed lag kinetics. Electron microscopy revealed the formation of small aggregates that subsequently grew to larger amorphous aggregates. The kinetics of aggregation produced surprising results: progress curves followed either by the binding of Thioflavin T or the fluorescence of the protein at 340 nm fitted well to simple two-step sequential first-order lag kinetics with rate constants
k
1
and
k
2
that were independent of protein concentration, and not to classical nucleation-growth. We suggest a mechanism of first-order formation of an aggregation competent state as being rate determining followed by rapid polymerization with the higher order kinetics. By measuring the inhibition kinetics of
k
1
and
k
2
, we resolved that the process with the higher rate constant followed that of the lower. Further, there was only partial inhibition of
k
1
and
k
2
, which showed two parallel pathways of aggregation, one via a state that requires unfolding of the protein and the other of partial unfolding with the ligand still bound. Inhibition kinetics of ligands provides a useful tool for probing an aggregation mechanism.