bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of solvent polarity and fractionation temperature on the physicochemical properties of squid viscera stearin
Authors: Yang M. H. , Chang S. C. , Chen R. H.
Published: May 2007

Complete utilization of squid viscera oil was found to be feasible by solvent fractionation. The effects of solvent polarity and temperature on yield, soft melting point, fatty acid composition and solid fat content of the stearin were studied. Although yield increased with increasing solvent polarity and with decreasing fractionation temperature, the stearin obtained has a lower soft melting point. This makes it unsuitable as a table margarine. Operation at lower temperature also increased the operating cost. Solid fat content of the stearins fractionated at‐1°C was 10% higher than of those at ‐5 or ‐9°C for all solvent polarities studied. Solid fat content of stearin increased with the decrease of solvent polarity at every tested temperature. The combined effects of polarity and fractionation temperature affect the soft melting point and solid fat content, which determine the commercial application of the stearin. The percentage of saturated fatty acids of stearin decreased with increasing solvent polarity, and the percentage of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) increased with solvent polarity and fractionation temperature. The percentage of EPA + DHA in stearin decreased with temperature, except for those from 5.1 p′ solvent. The practical fractionation condition is at ‐1 or ‐5°C with a solvent polarity of 5.1 p′. The stearin fraction can be made into a series of products, such as high EPA‐ and DHA‐containing table margarine.
Fatty acids and triacylglycerols of cherry seed oil
Authors: Comes F. , Farines M. , Aumelas A. , Soulier J.
Published: May 2007

Cherry seed oil, from the Rosaceae family, prunoid subfamily, is characterized by the existence of about 10% α‐eleostearic acid. The structure of the acid was proven by H and13C nuclear magnetic resonance. The triacylglycerols of this oil were identified and quantitated by highperformance liquid chromatography by means of several types of detectors. α‐Eleostearic acid was not found in the seeds of previously studied prunoids (almond, peach, apricot and plum). The main fatty acids found in the seeds of cherry and other prunoids were linoleic (L), oleic (O) and palmitic acids, and the major triacylglycerols were LLO, LOO and OOO. These chemical data support the botanical relationship within the prunoid subfamily and show the proximity of cherry to the Chrysobalanaceae family.
The kinetics of hydrolysis ofNigella sativa (black cumin) seed oil catalyzed by native lipase in ground seed
Authors: Dandik L. , Aksoy H. A.
Published: May 2007

Kinetics of the lipolysis ofNigella sativa oil catalyzed by native lipase in crushed seed were studied between 20 and 90°C. Data fitted the pseudo first‐order rate equation at 20, 30 and 40°C; and the pseudo second‐order equation at 50, 60 and 70°C, but neither equation fit at 80 and 90°C. Lipolysis approximated first‐order with respect to water.
Mass spectral studies of deuterium‐labelled picolinyl fatty esters in the determination of double‐bond positions
Authors: Lie Ken Jie Marcel S. F. , Choi Y. C.
Published: May 2007

Deuteration (with Wilkinson’s catalyst) of methyl 12:1(3c), 14:1(5c), 18:1(9c), 18:2(9c,12c), 18:3(9c,12c,15c), 20:4(5c,11c,14c,17c), 20:5(5c,8c,11c,14c,17c) and 22:6(4c,7c,10c,13c,16c,19c) fatty acids gave the corresponding deuterium‐labelled saturated fatty esters. The mass spectral analysis of their picolinyl esters gave clear diagnostic ion fragments, which permitted the facile and accurate determination of the positions of the double bonds (up to six) in the alkyl chain of the fatty ester.
Anhydrous esterification of myristic acid with propylene: Ion exchange resin and acid‐treated clay as catalysts
Authors: Chakrabarti Animesh , Sharma Man Mohan
Published: May 2007

Anhydrous esterification of myristic acid with propylene was carried out in the temperature range of 110–145°C and pressure from 190–195 psig in the presence of Amberlyst‐15 (cation exchange resin) and Filtrol‐24 (acid‐treated clay) as catalysts. The product ester, isopropyl myristate finds use in cosmetic and topical medicinal preparations where good absorption through the skin is desired. Filtrol‐24 is the catalyst of choice, and the recommended operating temperature is 130°C with a pressure of 190 psig.
Formation of toxic aldehydes in cod liver oil after ultraviolet irradiation
Authors: Niyati‐Shirkhodaee Fatemeh , Shibamoto Takayuki
Published: May 2007

Formaldehyde, acrolein, malonaldehyde (MA), acetaldehyde and propanal produced from cod liver oil upon ultraviolet irradiation (λmax=300 nm) were derivatized into nitrogenor sulfur‐containing compounds and then analyzed by capillary gas chromatography with a nitrogen‐phosphorus detector or a flame photometric detector. Acrolein and MA were formed at levels of 10.9±3.06 and 190.2±38.4 nmol/mg of fish oil, respectively. Maximum levels of formaldehyde, acetaldehyde and propanal formed were 7.0±0.90, 49.1±4.5 and 35.8±4.0 nmol/mg of oil, respectively. Formation of propanal in large quantities corresponded to the high content of ɛ‐3 fatty acids in cod liver oil.
A method for bleaching rice bran oil with silica gel
Authors: Krishna A. G. Gopala
Published: May 2007

The color of bleached rice bran oil can be improved by silica gel treatment of the oil miscella before or after dewaxing. A silica gel/oil/solvent ratio of 1:5:5 (wt/wt/vol) is suitable. Silica gel treatment can be carried out either by column percolation or by merely shaking the miscella with the gel followed by decantation. However, column percolation is more efficient, with 30–72% color reductionvs. 19–36% reduction for shaking and decanting.
Process Technology for the Production of Micronutrient Rich Red Palm Olein
Authors: Mayamol P. N. , Balachandran C. , Samuel T. , Sundaresan A. , Arumughan C.
Published: May 2007

Crude palm oil (CPO) is the richest natural source of carotenes that are destroyed in the conventional processing. There is a growing demand for nutritional products containing bioactive constituents externally fortified or preserved through modified process. A commercially viable process for the production of red palm olein (RPOn) rich in carotenes, tocols and sterols has been developed at pilot scale. The process developed involved neutralization of CPO followed by crystallization at controlled rate of cooling and deodorization of the resultant neutralized and winterized palm olein (WPOn) under controlled conditions of temperature and high vacuum. Analytical data related to micronutrients at each process step was monitored. The RPOn thus produced had not more than 0.25% of free fatty acids (FFA) and it retained more than 80% of the carotenes, about 85% of tocols and 65% of sterols originally present in the CPO. The physico‐chemical characteristics of RPOn revealed that it is nutritionally of superior quality compared to that of the commercial refined bleached deodorized (RBD) palm olein currently available in the market. The carotenes, tocols and sterols profile of RPOn by HPLC showed that they were retained in their natural forms.
Replicative senescence, telomere shortening and cell proliferation rate in Gaddi goat's skin fibroblast cell line
Authors: Gupta Neelam , Taneja Ritu , Pandey Alok , Mukesh Manishi , Singh Hari , Gupta S.C.
Published: May 2007

We assessed aging in continuous donor skin fibroblast cell line GGM5 up to the 25th passage by in vitro replicative senescence, telomere dynamics and chromosomal abnormalities. Cell proliferation rate increased from 0.84 ± 0.26 (primary cells) to 1.20 ± 0.17 (13–15 passage group) per day and reduced to 0.65 ± 0.14 in 22–25 passages. Cell proliferation rate was reduced by 45.7% after 87.62 CPDs. Cell viability reduced from 100% to 97.4% up to the 25th passages. Frequency of β gal+ cells increased in successive passages and days in culture. The correlation coefficient between frequency of β gal+ cells and growth rate was −0.50 to −0.61. Loss of mean TRF length was 13.8 nucleotides (passage 15) to 95.4 nucleotides per cell division in later passages. All cells showed Robertsonian translocation in 22–25 passaged cells. The SCNT pre‐implantation embryos production was highest (22.5%) in donor cells used from 10–15 passages as compared to early (≤5) and late (22–25 passages). Our findings supports that cell proliferation rates, β gal staining, mean TRF loss and karyological profile are useful marker for evaluation of competent nuclear donor.
Reactive oxygen species, but not mitochondrial membrane potential, is associated with radiation‐induced apoptosis of AHH‐1 human lymphoblastoid cells
Authors: Wang Zi‐Bing , Liu Yu‐Qing , Zhang Ying , Li Yan , An Xiao‐Xia , Xu Han , Guo Ying , Jin Wei , Jiang Zhu‐Jun , Cui Yu‐Fang
Published: May 2007

The aim of the study was to investigate the sensitivity of AHH‐1 human lymphoblastoid cells to radiation and its relevance to intracellular events, specifically alteration in cellular energy‐producing systems. AHH‐1 human lymphoblastoid cells were irradiated with 6 Gy of γ radiation, and then were collected at the indicated time points. Parallel studies were conducted to assess the effects of radiation on the cell proliferation and apoptotic index. Mitochondrial membrane potential (MMP) and reactive oxygen species (ROS) production were monitored. A marked decrease of cell viability was observed as early as 12 h postirradiation and fraction of apoptotic cells was highest at 24 h. Intracellular ROS generation measured with 2′,7′‐dichlorodihydrofluorescein diacetate (DCFH‐DA) appeared to be highest as early as 30 min postirradiation and resumed to normal level at 6 h. Unexpectedly, the fluorescence intensity of Rhodamine 123 for measuring MMP did not change during the first 3 h after radiation and exhibited an aberrant increase at 6 h. The results suggest that AHH‐1 cells are sensitive to radiation‐induced apoptosis and ROS generation is an early phase in the apoptosis process. Moreover, the results might cast doubts on those studies using Rhodamine 123 which hypothesized that the fall in MMP is one of the early events of apoptosis.
Complications of three sacrospinous ligament fixation techniques
Authors: Pollak J. , Takacs P. , Medina C.
Published: May 2007

Objectives: To compare the complications of three techniques used to pass the suture through the sacrospinous ligament when performing sacrospinous ligament fixation (SSLF): (1) the standard needle driver with direct visualization; (2) the Deschamps ligature carrier by palpation; and (3) the Miya hook ligature carrier by palpation. Materials and methods: A retrospective chart review of 240 patients undergoing SSLF was performed. A standard needle driver with direct visualization was used for 46 patients; the Deschamps ligature carrier was used for 173, and the Miya hook for 21 patients. Intraoperative and postoperative complications were compared between the groups. Results: Twelve women (5%) had intraoperative and forty women (17%) had postoperative complications suspected directly from the suture placement. There was no statistically significant difference in the rate of total intraoperative complications among the three groups. The proportion of patients with postoperative complications that were felt to be directly related to the suture passage technique was significantly higher in the Deschamps group compared to the direct visualization group (18% vs 2%, P = 0.002). Conclusion; Passing the suture through the sacrospinous ligament under direct visualization may result in less intra and postoperative complications.
The erosion of vospitaniye (social upbringing) in post-Soviet Kyrgyzstan: Voices from the schools
Authors: DeYoung Alan J.
Published: May 2007

Independent Kyrgyzstan has inherited the Soviet school system, including vospitaniye as an essential part. Soviet social policy was driven by the belief that building communism partly depended upon the creation of the ‘‘Soviet man.’’ Such an individual would demonstrate unwavering commitment to aims of the October Revolution, and desire to undertake the technological and scientific training required to achieve collective purposes. The resulting social cohesion among like-minded individuals would thus reinforce the economic and political aims of the USSR. A primary institutional location for the creation of such individuals was the secondary school, formally organized to achieve two distinct but equally important goals: the transmission of formal knowledge (obrazovaniye) and the process of social upbringing (vospitaniye). This paper first considers the critical nature of vospitaniye as an aim of the USSR, an aim typically underestimated in the current discourse of reforming post-Soviet schools. It then suggests contemporary dilemmas voiced by practicing educators in several Kyrgyz schools who are still charged with social upbringing, but in a climate where the ideals and values upon which vospitaniye was initially created appear no longer viable.
Episodes of late Holocene aridity recorded by stalagmites from Devil's icebox Cave, Central Missouri, USA
Authors: Denniston Rhawn F. , DuPree Michelle , Dorale Jeffrey A. , Asmerom Yemane , Polyak Victor J. , Carpenter Scott J.
Published: May 2007

Two stalagmites from Devil's Icebox Cave, central Missouri, display similar δ13C and δ18O values and trends during the late Holocene. Positive δ13C excursions at 3.5–2.6 ka and 1.2–0.9 ka are interpreted to reflect drier conditions. These elevated stalagmite δ13C values could have plausibly been driven by increasing C4 plant abundances over the cave or an increased contribution of bedrock carbon, both of which could reflect decreased effective moisture. A lack of corresponding oxygen isotopic anomalies during these intervals suggests that neither mean annual temperature nor the seasonality of precipitation changed concomitantly with dryness. Both of the δ13C excursions identified in our stalagmite record are roughly coincident with dry intervals from a number of sites located across the Great Plains.
Comparative Analysis of Splice Site Regions by Information Content
Authors: Rekha T. Shashi , Mitra Chanchal K.
Published: May 2007

We have applied concepts from information theory for a comparative analysis of donor (gt) and acceptor (ag) splice site regions in the genes of five different organisms by calculating their mutual information content (relative entropy) over a selected block of nucleotides. A similar pattern that the information content decreases as the block size increases was observed for both regions in all the organisms studied. This result suggests that the information required for splicing might be contained in the consensus of ~6–8 nt at both regions. We assume from our study that even though the nucleotides are showing some degrees of conservation in the flanking regions of the splice sites, certain level of variability is still tolerated, which leads the splicing process to occur normally even if the extent of base pairing is not fully satisfied. We also suggest that this variability can be compensated by recognizing different splice sites with different spliceosomal factors.
A Network Partition Algorithm for Mining Gene Functional Modules of Colon Cancer from DNA Microarray Data
Authors: Ruan Xiao-Gang , Wang Jin-Lian , Li Jian-Geng
Published: May 2007

Computational analysis is essential for transforming the masses of microarray data into a mechanistic understanding of cancer. Here we present a method for finding gene functional modules of cancer from microarray data and have applied it to colon cancer. First, a colon cancer gene network and a normal colon tissue gene network were constructed using correlations between the genes. Then the modules that tended to have a homogeneous functional composition were identified by splitting up the network. Analysis of both networks revealed that they are scale-free. Comparison of the gene functional modules for colon cancer and normal tissues showed that the modules’ functions changed with their structures.
KaKs_Calculator: Calculating Ka and Ks Through Model Selection and Model Averaging
Authors: Zhang Zhang , Li Jun , Zhao Xiao-Qian , Wang Jun , Wong Gane Ka-Shu , Yu Jun
Published: May 2007

KaKs_Calculator is a software package that calculates nonsynonymous (Ka) and synonymous (Ks) substitution rates through model selection and model averaging. Since existing methods for this estimation adopt their specific mutation (substitution) models that consider different evolutionary features, leading to diverse estimates, KaKs_Calculator implements a set of candidate models in a maximum likelihood framework and adopts the Akaike information criterion to measure fitness between models and data, aiming to include as many features as needed for accurately capturing evolutionary information in protein-coding sequences. In addition, several existing methods for calculating Ka and Ks are also incorporated into this software. KaKs_Calculator, including source codes, compiled executables, and documentation, is freely available for academic use at http://evolution.genomics.org.cn/software.htm.
Body fat content and feeding level interact strongly in the short- and medium-term regulation of plasma leptin during underfeeding and re-feeding in adult sheep
Authors: Delavaud Carole , Bocquier François , Baumont René , Chaillou Elodie , Ban-Tokuda Tomomi , Chilliard Yves
Published: May 2007

Circulating leptin is regulated by food intake in the long, medium and short term; however, little is known about putative remnant effects of these successive regulations at any given time. To clarify this, two experiments were conducted in adult sheep, during which body condition parameters and plasma leptin were measured. During experiment 1, twenty ewes with normal body condition were either well fed (101 % of maintenance energy requirements (MER)) or underfed (41 % MER) for 166 d, then rapidly re-fed (at a mean of 208 % MER) for 3 d. Leptinaemia decreased after 14 d of underfeeding, remained depressed until day 166 and did not increase after 3 d re-feeding, whereas it was increased (+153 %;P < 0·05) by re-feeding the previously well-fed ewes. During experiment 2, twenty-four fat or lean ewes were either well fed (114 % MER) or underfed (52 % MER) for 94 d, and gradually re-fed for 2 d and maintained at a high feeding level (235 % MER) for 9 d. Underfeeding decreased leptinaemia in fat (from 4·19 to 2·63 ng/ml) but not lean ewes, and re-feeding increased leptinaemia after 5 d in lean previously well-fed (+123 %;P < 0·05) but not underfed ewes. In fat ewes, the impact of re-feeding was rapid (+144 %;P < 0·001 at 5 d) in previously well-fed ewes, whereas it was more gradual with a maximum at 11 d (+162 %;P < 0·01) in previously underfed ewes. In conclusion, leptinaemia is modulated by short-term energy intake level in interaction with long-term regulations involving nutritional history and body fatness, suggesting that a biological threshold of adiposity (about 20 %) is necessary to allow short- and medium-term leptin regulation.
Dietary patterns and their correlates among middle-aged and elderly Chinese men: a report from the Shanghai Men's Health Study
Authors: Cai Hui , Zheng Wei , Xiang Yong-Bing , Hong Xu Wang , Yang Gong , Li Honglan , Ou Shu Xiao
Published: May 2007

Dietary patterns, which reflect the complexity of food preference, lifestyle and socio-economic status, may play a major role in health and longevity. Understanding dietary patterns and their correlates is important to the research of diet and health relationships. In the Shanghai Men's Health Study (SMHS) a total of 61 582 men aged 40–74 were recruited between 2002 and 2006. Their food intake over the previous year was collected using a validated FFQ. Study participants (75·6 %) reported little or no change in meat and vegetable intake in the 5 years prior to recruitment. Using the baseline data of the SMHS, we assessed dietary patterns, as well as their relationship with socio-demographic and lifestyle factors and with prevalence of some chronic diseases. Three major dietary patterns, fruit-, vegetable- and meat-based diets, were identified in our population. Consumption of the fruit diet appeared to be more common among men who were older and more physically active, had higher income, and lower waist-to-hip ratio (WHR), while this diet was less common among manual labourers. The meat- or vegetable-based diets were less common among elderly men and more common among men with higher WHR. Dietary patterns appeared to be associated with the presence of health conditions. In general, subjects with a chronic disease were more likely to have the vegetable-based diet and less likely to have the fruit- or meat-based diets. Future studies of diet and health in this population will need to carefully take into account these potential confounders.
Acquired immunodeficiency syndrome related Kaposi's sarcoma eroding the maxillary bone
Authors: Konstantinopoulos P A , Goldsztein H , Dezube B J , Pantanowitz L
Published: May 2007

Background:

Oral involvement is a common manifestation of acquired immunodeficiency syndrome related Kaposi's sarcoma, and it occurs in approximately one-third of afflicted patients.

Methods:

We report an unusual case of Kaposi's sarcoma of the hard palate which invaded the underlying maxillary bone.

Results:

The patient underwent excisional biopsy and was subsequently treated with localised radiation and systemic chemotherapy including liposomal doxorubicin.

Conclusions:

The presentation, differential diagnosis, radiographic appearance and management of this serious complication are discussed. Our case highlights the need for a multidisciplinary approach, consisting of ENT, oncology and infectious disease consultation, to ensure appropriate management of maxillofacial, intraosseous, acquired immunodeficiency syndrome related Kaposi's sarcoma.
Mutational falsetto: intervention outcomes in 45 patients
Authors: Dagli M , Sati I , Acar A , Stone R E , Dursun G , Eryilmaz A
Published: May 2007

Objective:

The aim of this study was to evaluate the outcomes of therapeutic intervention in patients with mutational falsetto, by applying perceptual and acoustic analysis before and after voice therapy.

Materials and methods:

Forty-five consecutive patients with mutational falsetto were studied retrospectively. Acoustic analysis (i.e. fundamental frequency, jitter, shimmer, and formants one, two and three) was performed using the Multi-Dimensional Voice Program. Perceptual voice analyses were performed, including graded severity–roughness–breathiness–aesthenicity–strain assessment.

Results:

Subjects' fundamental frequency, voice formants one, two and three, jitter, and shimmer were greater before than after treatment. There were statistically significant differences between pre- and post-treatment average values for fundamental frequency, jitter and shimmer. There were also statistically significant differences between pre- and post-treatment average values for formants one and two. These results were maintained after six months of follow up, and there was no significant difference between results at three- and six-month follow up. According to perceptual evaluation, each subject's voice had altered from mutational falsetto to chest voice by completion of the intervention. Thus, all of the patients successfully lowered their modal speaking voice to an appropriate level.

Conclusion:

In the light of objective evaluations, and by applying the study treatment protocol, these results suggest that normal voice can be maintained after intervention, at six months' follow up.
Wave kinetic description of quantum pair plasmas
Authors: MENDONÇA J. T. , RIBEIRO J. E. , SHUKLA P. K.
Published: May 2007

The dispersion relation for a quantum pair plasma is derived, by using a wave kinetic description. A general form of the kinetic dispersion relation for electrostatic waves in a two-component quantum plasma is established. The particular case of an electron–positron pair plasma is considered in detail. Exact expressions for Landau damping are derived, and the quasi-classical limit is discussed.
Argument diagramming in logic, law and artificial intelligence
Authors: REED CHRIS , WALTON DOUGLAS , MACAGNO FABRIZIO
Published: May 2007

In this paper, we present a survey of the development of the technique of argument diagramming covering not only the fields in which it originated — informal logic, argumentation theory, evidence law and legal reasoning — but also more recent work in applying and developing it in computer science and artificial intelligence (AI). Beginning with a simple example of an everyday argument, we present an analysis of it visualized as an argument diagram constructed using a software tool. In the context of a brief history of the development of diagramming, it is then shown how argument diagrams have been used to analyse and work with argumentation in law, philosophy and AI.
Unofficial road building in the Brazilian Amazon: dilemmas and models for road governance
Authors: PERZ STEPHEN G. , OVERDEVEST CHRISTINE , CALDAS MARCELLUS M. , WALKER ROBERT T. , ARIMA EUGÊNIO Y.
Published: May 2007

Unofficial roads form dense networks in landscapes, generating a litany of negative ecological outcomes, but in frontier areas they are also instrumental in local livelihoods and community development. This trade-off poses dilemmas for the governance of unofficial roads. Unofficial road building in frontier areas of the Brazilian Amazon illustrates the challenges of ‘road governance.’ Both state-based and community-based governance models exhibit important liabilities for governing unofficial roads. Whereas state-based governance has experienced difficulties in adapting to specific local contexts and interacting effectively with local peoples, community-based governance has a mixed record owing to social inequalities and conflicts among local interest groups. A state-community hybrid model may offer more effective governance of unofficial road building by combining the oversight capacity of the state with locally-grounded community management via participatory decision-making.
What is Seen Through the Looking Glass: The Impact of Training on Practitioner Self-Rating of Motivational Interviewing Skills
Authors: Hartzler Bryan , Baer John S. , Dunn Chris , Rosengren Dave B. , Wells Elizabeth
Published: May 2007

Training efforts for evidenced based treatments require evaluation, yet the value of practitioner self-reports of skills acquisition has been questioned. Thus, a key issue concerns how accurately practitioners assess their own clinical skills. In the current study, 23 community practitioners participated in training of Motivational Interviewing (MI), completed standardized patient (SP) interviews before and after training, and provided self-ratings of MI elements after each interview. Interview recordings were later coded independently. Results suggest training contributed to: 1) reasonable agreement between practitioner and independent ratings; and 2) more effective use of MI, despite a tendency for practitioners to underestimate training gains. This micro-analysis of training documents initial skill gains along with increased practitioner self-awareness. Further, it exemplifies how practitioner self-ratings and objective skill assessment methods may be used in tandem to more fully describe practitioner learning.
Propositional theories are strongly equivalent to logic programs
Authors: CABALAR PEDRO , FERRARIS PAOLO
Published: May 2007

This paper presents a property of propositional theories under the answer sets semantics (called Equilibrium Logic for this general syntax): any theory can always be reexpressed as a strongly equivalent disjunctive logic program, possibly with negation in the head. We provide two different proofs for this result: one involving a syntactic transformation, and one that constructs a program starting from the countermodels of the theory in the intermediate logic of here-and-there.
Suzaku observation of the black hole transient 4U1630–472: discovery of absorption lines
Authors: Kubota Aya , Dotani Tadayasu , Cottam Jean , Kotani Taro , Done Chris , Ueda Yoshihiro , Fabian Andy C. , Yasuda Tomonori , Takahashi Hiromitsu , Fukazawa Yasushi , Yamaoka Kazutaka , Makishima Kazuo , Yamada Shinya , Kohmura Takayoshi , Angelini Lorella ,   the Suzaku team
Published: May 2007

We present the results of six Suzaku observations of the recurrent black hole transient 4U 1630–472 during its decline from its most recent outburst in 2006. All observations show the typical high/soft state spectral shape in the 2–50 keV band, roughly described by an optically thick disk spectrum in the soft energy band plus a weak power-law tail.

The disk temperature decreases from 1.4 keV to 1.2 keV as the flux decreases by a factor 2, consistent with a constant radius as expected for disk-dominated spectra. All the observations reveal significant absorption lines from highly ionized (H-like and He-like) iron Kα at 7.0 keV and 6.7 keV.

The energies of these absorption lines suggest a blue shift with an outflow velocity of ∼1000 km s−1. The H–like iron Kα equivalent width remains approximately constant at ∼30 eV over all the observations, while that of the He–like Kα line increases from 7 eV to 20 eV. Thus the ionization state of the material decreases, as expected from the decline in flux.

The data constrain the velocity dispersion of the absorber to 200–2000 km s−1, and the size of the plasma as ∼1010 cm assuming a source distance of 10 kpc.
Massive black holes: formation and evolution
Authors: Rees Martin J. , Volonteri Marta
Published: May 2007

Supermassive black holes are nowadays believed to reside in most local galaxies. Observations have revealed us vast information on the population of local and distant black holes, but the detailed physical properties of these dark massive objects are still to be proven. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. We briefly review here the basic properties of the population of supermassive black holes, focusing on the still mysterious formation of the first massive black holes, and their evolution from early times to now.
Variable and polarized emission from SgrA*
Authors: Eckart A. , Schödel R. , Meyer L. , Straubmeier C. , Dovčiak M. , Karas V. , Morris M. R. , Baganoff F. K.
Published: May 2007

The super-massive black hole in the Galactic Center (Sagittarius A*) is one of the most exciting targets in the sky. At a distance of ∼ 8 kpc it is about one hundred times closer than the second nearest nucleus of a similar galaxy, M31, and therefore the closest galactic nucleus that we can study. Here we report on the modeling of polarized near-infrared flare emission from SgrA* using a model in which a hot spot is moving on a relativistic orbit around the massive black hole. We also summarize the results from simultaneous radio/near-infrared/X-ray measurements of flare emission.
Observational evidence for intermediate-mass black holes: ultra-luminous X-ray sources
Authors: Makishima Kazuo
Published: May 2007

Incorporating early data from the Suzaku satellite launched in July 2005, properties of Ultra-Luminous compact X-ray sources (ULXs) were studied in close comparison with those of Galactic and Magellanic black-hole binaries. Based on an analogy between these two types of X-ray sources, ULXs showing power-law type spectra are considered to host Comptonized accretion disks, while those with multicolor-disk type spectra are interpreted to harbor “slim” disks. The analogy also suggests that ULXs are radiating near their Eddington limits, and hence their central black holes are significantly more massive than the ordinary stellar-mass black holes contained in Galactic and Magellanic black-hole binaries. In this sense, ULXs can be regarded as intermediate-mass black holes.
The optical counterpart of the ultraluminous X-ray source NGC6946 ULX-1
Authors: Abolmasov P. K. , Fabrika S. N. , Sholukhova O. N.
Published: May 2007

We present a study of a peculiar nebula MF16 associated with an Ultraluminous X-ray Source NGC6946 ULX-1. We use integral-field and long-slit spectral data obtained with the 6-m telescope (Russia). The nebula was for a long time considered powered by strong shocks enhancing both high-excitation and low-excitation lines. However, kinematical properties point to rather moderate expansion rates (VS ∼ 100÷200 km s−1). The total power of the emission-line source exceeds by one or two orders of magnitude the power observed expansion rate can provide, that points towards the existence of an additional source of excitation and ionization. Using CLOUDY96.01 photoionization code we derive the properties of the photoionizing source. Its total UV/EUV luminosity must be about 1040 erg/s.
Recipes for ULX formation: necessary ingredients and garnishments
Authors: Soria Roberto
Published: May 2007

We summarize the main observational features that seem to recur more frequently in the ULX population. We speculate that low metal abundance, and clustered star formation triggered by molecular cloud collisions are two fundamental physical requirements for ULX formation. In this scenario, most ULXs are formed from recent stellar processes, have black hole (BH) masses <100 M⊙, and do not require merger processes in super-star-clusters.
Explosion of very massive stars and the origin of intermediate mass black holes
Authors: Tsuruta Sachiko , Ohkubo Takuya , Umeda Hideyuki , Maeda Keiichi , Nomoto Ken'ichi , Suzuki Tomoharu , Rees Martin J.
Published: May 2007

We calculate evolution, collapse, explosion, and nucleosynthesis of Population III very massive stars with 500 M⊙ and 1000 M⊙. It was found that both 500 M⊙ and 1000 M⊙ models enter the region of pair-instability but continue to undergo core collapse to black holes. For moderately aspherical explosions, the patterns of nucleosynthesis match the observational data of intergalactic and intercluster medium and hot gases in M82, better than models involving hypernovae and pair instability supernovae.

Our results suggest that explosions of Population III core-collapse very massive stars contribute significantly to the chemical evolution of gases in clusters of galaxies. The final black hole masses are about 500 M⊙ for our most massive 1000 M⊙ models. This result may support the view that Population III very massive stars are responsible for the origin of intermediate mass black holes which were recently reported to be discovered.
The gravitational redshift in the broad line region of the active galactic nucleus Mrk 110
Authors: Gavrilović N. , Popović L.Č , Kollatschny W.
Published: May 2007

We used the long term spectroscopic observations of Mrk 110 (Hα and Hβ lines) to investigate the gravitational field influence on spectral line profiles. We found that effects of gravitational field can be measured and that the lines are more intense where the emission is originating close to the central black hole of Mrk 110.
AGN polarization modeling with Stokes
Authors: Goosmann René W. , Gaskell C. Martin , Shoji Masatoshi
Published: May 2007

We introduce a new, publicly available Monte Carlo radiative transfer code, Stokes, which has been developed to model polarization induced by scattering of free electrons and dust grains. It can be used in a wide range of astrophysical applications. Here, we apply it to model the polarization produced by the equatorial obscuring and scattering tori assumed to exist in active galactic nuclei (AGNs). We present optical/UV modeling of dusty tori with a curved inner shape and for two different dust types. The polarization spectra enable us to clearly distinguish between the two dust compositions. The Stokes code and its documentation can be freely downloaded from http://www.stokes-program.info/.
Measuring the supermassive black hole parameters with space missions
Authors: Zakharov Alexander F.
Published: May 2007

Recent X-ray observations of microquasars and Seyfert galaxies reveal broad emission lines in their spectra, which can arise in the innermost parts of accretion disks. Recently Müller & Camenzind (2004) classified different types of spectral line shapes and described their origin. Zakharov (2006b) clarified their conclusions about an origin of doubled peaked and double horned line shapes in the framework of a radiating annulus model and discussed s possibility to evaluate black hole parameters analyzing spectral line shapes.
Ramp initiation and spacing in a homogeneous thrust wedge
Authors: Panian John , Wiltschko David
Published: May 2007

Fold‐and‐thrust belts grow largely through sequential initiation of thrust faults and subsequent motion on them from hinterland to foreland, i.e., away from the plate boundary. While perturbations in basal geometry, stratigraphy, excess fluid pressure, folding, and surface slope have all been suggested as mechanisms for thrust ramp nucleation, we show that preexisting inhomogeneities are not necessary. We present a mechanically homogeneous finite element wedge model to assess the effects of variations in yield stress, dilation angle, and basal friction angle on foreland fold‐and‐thrust belt evolution. Computer experiments produce a broad foreland dipping plastic strain band that marks the topographic inflection produced by the previous ramp. This band migrates toward the rigid base, where the plastic strain is preferentially concentrated in a thrust ramp. Subsequent ramps develop toward the foreland in a self‐similar fashion. The ramp formation process is systematic. Ramps form at the same location with respect to the wedge origin regardless of significant variations in yield stress, dilation angle, or basal friction. However, the backstop displacement required to initiate a new ramp is dependent on these variables. We conclude that the wedge geometry is the primary factor in determining both thrust ramp location and spacing. Syntectonic erosion and deposition, or any other process that changes wedge geometry, may in some cases control the location of thrust ramps.
Season‐dependent dynamics of nonlinear optimal error growth and El Niño‐Southern Oscillation predictability in a theoretical model
Authors: Mu Mu , Duan Wansuo , Wang Bin
Published: May 2007

Most state‐of‐the‐art climate models have difficulty in the prediction of El Niño‐Southern Oscillation (ENSO) starting from preboreal spring seasons. The causes of this spring predictability barrier (SPB) remain elusive. With a theoretical ENSO system model, we investigate this controversial issue by tracing the evolution of conditional nonlinear optimal perturbation (CNOP) and by analyzing the behavior of initial error growth. The CNOPs are the errors in the initial states of ENSO events, which have the biggest impact on the uncertainties at the prediction time under proper physical constraints. We show that the evolution of CNOP‐type errors associated with El Niño episodes depends remarkably on season with the fastest growth occurring during boreal spring in the onset phase. There also exist other kinds of initial errors, which have either somewhat smaller growth rates or neutral ones during spring. However, for La Niña events, even if initial errors are of CNOP‐type, the errors grow without significant seasonal dependence. These findings suggest that the SPB in this model results from combined effects of three factors: the annual cycle of the mean state, the structure of El Niño, and the pattern of the initial errors. On the basis of the error tendency equations derived from the model, we addressed how the combination of the three factors causes the SPB and proposed a mechanism responsible for the error growth in the model ENSO events. Our results help in clarifying the role of the initial error pattern in SPB, which may provide a clue for explaining why SPB can be eliminated by improving initial conditions. The results also illustrate a theoretical basis for improving data assimilation in ENSO prediction.
Variations of the ACC‐CDW during MIS3 traced by magnetic grain deposition in midlatitude South Indian Ocean cores: Connections with the northern hemisphere and with central Antarctica
Authors: Mazaud A. , Kissel C. , Laj C. , Sicre M. A. , Michel E. , Turon J. L.
Published: May 2007

We examine the magnetic mineral deposition in three cores located at midlatitude sites in the South Indian Ocean, in an area where sediment eroded from the Kerguelen‐Crozet plateau and transported by the marine currents, principally the Antarctic Circum Current, accumulates at a high sedimentation rate. We focus on Marine Isotopic Stage 3, characterized by large climatic fluctuations at northern latitudes, and compare the obtained records to the climatic records at Byrd (Antarctica) and Summit (GISP2, Greenland) and to the North Atlantic Deep Water variations in the North Atlantic. Magnetic mineral deposition at the studied sites exhibits a profile with maxima at the time of Heinrich events H4 and H5, which suggests a strong Antarctic Circum Current when the North Atlantic Deep Water was reduced at northern latitude during these events. We show that an interhemispheric seesaw, characterized by temporary surface warmings in the southern hemisphere, is also marked by a strong Antarctic Circum Current at the time of the northern Heinrich events. The rapid Dansgaard‐Oeschger oscillations evidenced in the northern records after interstadials IS12 and IS8 are not visible, suggesting a limited counterpart of these events in the midlatitude southern Indian Ocean.
Prompt thermospheric response to the 6 November 2001 magnetic storm
Authors: Mishin E. V. , Marcos F. A. , Burke W. J. , Cooke D. L. , Roth C. , Petrov V. P.
Published: May 2007

Thermospheric densities observed by the STAR accelerometer on CHAMP, near 400 km altitude, are used to examine the response to the major geomagnetic storm on 6 November 2001. This is the first large storm studied with CHAMP data at these near dawn‐dusk local times. New features of the neutral density response at both global and local temporal/spatial scales have been revealed. Prompt response of the neutral atmosphere observed at the beginning of the storm was enriched by short‐ and meso‐scale perturbations. Simultaneous observations of electromagnetic and ionospheric plasma perturbations and particle precipitations from the DMSP satellites, electron energy fluxes from NOAA‐14 and Polar/UVI specified the energy source and the time delay. The suggested mechanism for this prompt thermospheric response appears to be due mainly to enhanced perpendicular electric fields. Large‐scale, global changes caused by the geomagnetic storm show generally greater enhancements in the winter (northern) hemisphere at both 0700 and 1900 local time and greater at 0700 LT than 1900 LT.
Spatial‐Temporal characteristics of ion beamlets in the plasma sheet boundary layer of magnetotail
Authors: Grigorenko Elena E. , Sauvaud Jean‐Andre , Zelenyi Lev M.
Published: May 2007

The processes of nonadiabatic ion acceleration occurring in the vicinity of magnetic neutral lines produce highly accelerated (up to 2500 km/s) field‐aligned ion beams (beamlets) with transient appearance streaming earthward in the plasma sheet boundary layer (PSBL) of the Earth’s magnetotail. Previous studies of these phenomena based on single spacecraft (s/c) missions supported the view that beamlets are temporal transients, since the typical time of a beamlet observation at a given s/c very rarely exceeds ∼1–2 min. Now multipoint Cluster observations have led to a new understanding of these phenomena with a spatial rather than a temporal structure. On the basis of 3‐year Cluster measurements made in the PSBL, we present statistical evaluation of the beamlet duration (at least 5–15 min) and confirm well‐manifested localization of the beamlet along Z and in some cases along Y directions, i.e., approximately across the lobe magnetic field. Earlier results reporting shorter beamlet observations could be understood by invoking not only PSBL flapping motions but also of an additional effect revealed by Cluster: earthward propagation of kink‐like perturbations along the beamlet filaments. Phase velocity of these perturbations is of the order of the local Alfven velocity (V ∼ 600–1400 km/s) and related fast flappings of localized beamlet structures in the Y‐Z direction significantly decreasing the time of their observation at a given spacecraft. Multipoint observations of beamlets revealed that they represent long‐living (∼5–15 min) plasma filaments elongated along the lobe magnetic field (∼60–100RE) and strongly localized in direction perpendicular to the PSBL‐lobe boundary (∼0.2–0.7RE). In some cases, it was also possible to estimate the width of beamlet in dawn‐dusk direction which was of the order of fractions of RE.
A scale‐free analysis of magnetic holes at 1 AU
Authors: Stevens M. L. , Kasper J. C.
Published: May 2007

We describe a scale‐free search for magnetic holes in the solar wind using Wind magnetometer observations between 1994 and 2004. Using magnetic field and ion measurements on the Wind spacecraft, we present the first statistical study of magnetic hole plasma signatures on the kinetic scale and we evaluate magnetic holes as kinetic and fluid phenomena. Magnetic holes are shown to be pressure‐balanced structures with similar properties on all scales. Temperature anisotropy measurements are combined with magnetic field measurements to give direct evidence that magnetic holes observed at 1 AU are stable remnants of magnetic pressure depletions generated in a source region closer to the Sun, likely through the mirror‐mode instability.
Conditions for intense ionospheric storms expanding to lower midlatitudes
Authors: Maruyama Takashi , Nakamura Maho
Published: May 2007

For studying conditions of intense ionospheric storms at lower midlatitudes, several storms that occurred in March and April 2001 were compared. In the two largest magnetic disturbances that occurred during this period, the disturbance (Dst) index reached −387 and −271 nT. The two largest ionospheric storms occurred in response to other weaker magnetic disturbances, in which Dst reached −149 and −102 nT. For the largest ionospheric storms on 21 March 2001 and 22 April 2001, a sequence of ionospheric and thermospheric disturbances was analyzed. We found that a nighttime disturbance dynamo plays an important role in expanding ionospheric storms to lower latitudes. When an eastward disturbance dynamo electric field forms after midnight, the ionospheric layer is uplifted, and the ion drag is reduced. The storm‐time equatorward surge effectively reaches lower‐latitude regions without decaying under the condition of reduced ion drag. The equatorward surge pushes up the ionosphere, in turn, and the ion drags might be further reduced. The large event‐to‐event variation of ionospheric storms might be partly owing to such a positive feedback process in addition to the well‐known local time effect.
Seismic velocity reductions caused by the 2003 Tokachi‐Oki earthquake
Authors: Rubinstein Justin L. , Uchida Naoki , Beroza Gregory C.
Published: May 2007

We use four repeating earthquake sequences located near Hokkaido to identify velocity changes caused by the Mw 8.0 2003 Tokachi‐Oki earthquake. Using a moving window cross‐correlation technique, we identify delays in the arrival time of seismic waves that accumulate linearly with time into the seismogram. This behavior is indicative of multiple scattering within a medium where the seismic velocity has been reduced. For all of our earthquake‐receiver geometries, we find evidence of significant velocity reductions close to the receiver. The correlation of the size of the velocity reductions with both strong shaking and site characteristics suggests that these velocity reductions are caused by damage to near‐surface materials created by nonlinear strong ground motion. For earthquake/receiver geometries where the seismic waves cross the Tokachi‐Oki rupture zone, we identify particularly large reductions in velocity as a result of the earthquake. For these geometries, we believe that the rupture zone of the Tokachi‐Oki earthquake or the shallow crust above it represents a second region where seismic velocities are reduced as a result of the main shock.