bluuebunny/crossref_metadata_2025_split huggingface dataset:
AGN-controlled cooling in elliptical galaxies
Authors: Best P. N. , Kaiser C. R. , Heckman T. M. , Kauffmann G. 
Published: March 2006

Abstract
A long-standing problem for models of galaxy formation has been the mismatch between the predicted shape of the mass function of dark matter halos and the observed shape of the luminosity function of galaxies. The number of massive haloes is predicted to decrease as a power law (N∝M−2) out to very large masses, while the galaxy luminosity function cuts off exponentially at luminosities above L*. This implies that the efficiency with which gas cools onto massive systems is lower than expected. This letter investigates the role of radio-loud active galactic nuclei (AGN) in continually re-heating the cooling gas. By combining two observational results, the time-averaged energy output associated with recurrent radio source activity is determined, as a function of the black hole mass of the host galaxy: . It is shown that for massive elliptical galaxies this radio-source heating balances the radiative energy losses from the hot gas surrounding the galaxy. The recurrent radio-loud AGN activity may therefore provide a self-regulating feedback mechanism capable of controlling the rate of growth of galaxies.
The growth of the nuclear black holes in submillimetre galaxies
Authors: Granato G. L. , Silva L. , Lapi A. , Shankar F. , De Zotti G. , Danese L. 
Published: March 2006

Abstract
We show that the ABC scenario we proposed for the co-evolution of spheroids and QSOs predicts accretion rates and masses of supermassive black holes in submillimetre galaxies in keeping with recent X-ray determinations. These masses are well below the local values as well as those predicted by alternative models. The observed column densities may be mostly due to interstellar medium in the galaxy. The contribution of the associated nuclear activity to the X-ray background is likely negligible, while they may contribute a sizeable fraction of ∼10 per cent to hard X-ray cumulative counts at the faintest observed fluxes.
Psychosocial Differences Between Whites and African Americans Living With HIV/AIDS in Rural Areas of 13 US States
Authors: Heckman Bernadette Davantes 
Published: March 2006

ABSTRACT:
Context: Acquired immunodeficiency syndrome (AIDS) prevalence rates are increasing rapidly in rural areas of the United States. As rural African Americans are increasingly affected by human immunodeficiency virus (HIV), it is important to identify psychosocial factors unique to this group so that AIDS mental health interventions can be culturally contextualized to meet their unique needs. Purpose: The current study characterized psychosocial functioning in 43 rural African Americans living with HIV/AIDS and compared their levels of functioning to those of 196 HIV‐infected rural white persons. Methods: All participants were recruited through AIDS service organizations in 13 US states. Surveys were completed as part of a preintervention phase of a randomized clinical trial evaluating 2 mental health interventions for HIV‐infected rural persons. Findings: Compared to their white counterparts, fewer African Americans had progressed to AIDS. African American participants also reported higher levels of coping self‐efficacy, more support from family members, and marginally fewer depressive symptoms, and they engaged in more active coping. African Americans who had greater HIV disease severity also received less support from family members and experienced more loneliness. Conclusions: Study findings caution that rural African Americans and whites living with HIV disease should not be considered a homogeneous group.
Variations in Health Insurance Coverage for Rural and Urban Nonelderly Adult Residents of Florida, Indiana, and Kansas
Authors: Hu Hsou Mei , Duncan R. Paul , Radcliff Tiffany A. , Porter Colleen K. , Hall Allyson G. 
Published: March 2006

ABSTRACT:
Context: Evidence exists for differences in health insurance coverage among states, but less is known about variations across different kinds of communities within states. Purpose: This article assesses the role of residential setting (metropolitan county, rural adjacent, and rural nonadjacent) in health insurance coverage for adult residents, under age 65, using data from large‐scale surveys collected in 3 diverse states (Florida, Indiana, and Kansas). Methods: Descriptive statistics are provided, and logistic regression models are used to examine the relationship between uninsurance status and residential settings while controlling for personal characteristics. Adjusted uninsurance rates by residential settings are presented for each state. Findings: Residential settings are significantly associated with uninsurance status in 2 of the 3 states we examined. We find that adult Floridians of rural adjacent counties are more likely to be uninsured than those in urban counties, but, for Indiana residents, uninsurance status is comparable between urban and rural adjacent residents. Rural nonadjacent Indiana residents are more likely to be uninsured compared to those in urban counties. The insurance status of adult Kansans does not vary across residential settings. Conclusion: Residential settings are significantly associated with being uninsured, but the significance of this link between residential locations and uninsurance status varies from state to state.
Planning and Providing End‐of‐life Care in Rural Areas
Authors: Wilson Donna M. , Justice Christopher , Sheps Sam , Thomas Roger , Reid Pam , Leibovici Karen 
Published: March 2006

ABSTRACT:
Context: Approximately 20% of North Americans and 25% of Europeans reside in rural areas. Planning and providing end‐of‐life (EOL) care in rural areas presents some unique challenges. Purpose: In order to understand these challenges, and other important issues or circumstances, a literature search was conducted to assess the state of science on rural EOL care. Methods: The following databases were searched for articles published from 1988 through 2003: EMBASE, Medline, CINAHL, AHMED, Psychinfo, ERIC, HealthStar, Sociological Abstracts, and Cochrane. All articles were systematically reviewed. Findings: Thirty‐six research articles were identified. Only 1 randomized controlled trial was located. Most research was single site, small sample, and exploratory/descriptive in design. Four distinct foci in this body of research were noted: (1) identifying and describing differences between urban and rural EOL care; (2) exploring rural EOL care; (3) assessing the EOL needs and wishes of terminally ill or dying persons, their family members, and health care professionals in rural areas; and (4) exploring EOL education for rural EOL care providers. Conclusions: Although rural EOL care research is not extensive, the existing literature is helpful for realizing the importance of EOL care in rural communities, as well as for conceptualizing and planning EOL care in rural communities. One of the chief considerations for rural EOL care is that dying at home is a common wish, with home‐based nursing care a key factor for this to become a reality. Another chief consideration is ensuring all rural health care professionals are both prepared for and supported while delivering EOL care.
The Characteristics of Successful Family Physicians in Rural Nebraska: A Qualitative Study of Physician Interviews
Authors: Backer Elisabeth L. , McIlvain Helen E. , Paulman Paul M. , Ramaekers Ryan C. 
Published: March 2006

ABSTRACT:
Context: In studying physician shortage issues, few studies have utilized individual interviews, allowing rural physicians to voice their own stories. Purpose: To explore rural physicians’ unique characteristics affecting their decisions and satisfactions with practice in a rural area. Methods: A qualitative interview study with 11 Nebraska family physicians practicing in rural (frontier) areas. Findings: Previous experience and preference for a rural lifestyle, desire for autonomy, a wide scope of practice, and close relationships with patients defined those physicians choosing rural practice.
Effects of exhaustive stretch‐shortening cycle exercise on muscle blood flow during exercise
Authors: Laaksonen M. S. , Kivelä R. , Kyröläinen H. , Sipilä S. , Selänne H. , Lautamäki R. , Nuutila P. , Knuuti J. , Kalliokoski K. K. , Komi P. V. 
Published: March 2006

AbstractAim:  The influence of exhaustive stretch‐shortening cycle exercise (SSC) on skeletal muscle blood flow (BF) during exercise is currently unknown.Methods:  Quadriceps femoris (QF) BF was measured in eight healthy men using positron emission tomography before and 3 days after exhaustive SSC exercise. The SSC protocol consisted of maximal and submaximal drop jumps with one leg. Needle biopsies of the vastus lateralis muscles were taken immediately and 2 days after SSC for muscle endothelial nitric oxide synthase (eNOS) and interleukin‐1‐beta (IL‐1β) mRNA level determinations.Results:  All subjects reported subjective muscle soreness after SSC (P < 0.001), which was well in line with a decrease in maximal isometric contraction force (MVC) and increase in serum creatine kinase activity (CK) (P = 0.018). After SSC muscle BF was 25% higher in entire QF (P = 0.043) and in its deep and superficial muscle regions, whereas oxygen uptake remained unchanged (P = 0.893). Muscle biopsies revealed increased IL‐1β (30 min: 152 ± 75%, P = 0.012 and 2 days: 108 ± 203%, P = 0.036) but decreased or unchanged eNOS (30 min; −21 ± 57%, P = 0.050 and 2 days: +101 ± 204%, P = 0.779) mRNA levels after SSC.Conclusion:  It was concluded that fatiguing SSC exercise induces increased muscle BF during exercise, which is likely to be associated with pro‐inflammatory processes in the exercised muscle.
Products of cyclooxygenase‐2 depress duodenal function in rats subjected to abdominal surgery
Authors: Pihl L. , Nylander O. 
Published: March 2006

AbstractAim:  Abdominal surgery evokes powerful biological responses that affect gastrointestinal functions. Here we investigate the role of the cyclooxygenase‐1 (COX‐1) and cyclooxygenase‐2 (COX‐2) isoforms in post‐operative duodenal ileus.Methods:  Proximal duodenum of anesthetized rats was perfused in situ with isotonic or hypotonic (50 mM) NaCl. Mucosal bicarbonate secretion, motility, mucosal permeability and effluent osmolality were determined in the absence and presence of different COX inhibitors.Results:  The majority of control animals had no or few duodenal contractions and bicarbonate secretion averaged 10.9 ± 1.4 μmol cm−1 h−1. These ‘paralytic’ controls responded to hypotonic NaCl with a small increase in mucosal permeability. In control animals exhibiting spontaneous duodenal contractions, the bicarbonate secretion was 50% higher and the hypotonicity‐induced net increase in mucosal permeability sevenfold higher than in ‘paralytic’ controls. Treatment with the selective COX‐2 inhibitors rofecoxib or parecoxib induced duodenal motility, increased bicarbonate secretion and potentiated the hypotonicity‐induced increase in mucosal permeability. COX‐2‐inhibited animals had a twofold greater capacity to adjust luminal osmolality than ‘paralytic’ controls. The selective COX‐1 inhibitor SC‐560 only transiently stimulated motility and bicarbonate secretion and the hypotonicity‐induced increase in mucosal permeability was smaller than in COX‐2‐inhibited animals.Conclusions:  Abdominal surgery increases the synthesis of prostanoids, particularly via the COX‐2 isoform. This compromises the ability of the duodenum to contract and to secrete HCO and to adjust luminal osmolality possibly via altered mucosal permeability. It is proposed that studies of gastrointestinal functions in animals subjected to abdominal surgery should include animals pre‐treated with a COX‐2 inhibitor.
Morphological Quantitation of Emphysema: A Debate
Authors: Weibel Ewald R. 
Published: March 2006

The following series of letters to the editor concerns a recently published morphologic method proposed by Parameswaran and colleagues for sensitive, early detection of emphysema ( J Appl Physiol 100: 186–193, 2006). The validity of the proposed method was critiqued by Ewald Weibel, and, in turn, this critique was rebutted by Parameswaran et al. Additional brief commentaries were contributed by scientists working in the field. Further comments on this important topic are welcome. The following is the abstract of the article discussed in the subsequent letter:The mean linear intercept ( Lm) can be used to estimate the surface area for gas exchange in the lung. However, in recent years it is most commonly used as an index for characterizing the enlargement of airspaces in emphysema and the associated severity of structural destruction in the lung. Specifically, an increase in Lmis thought to result from an increase in airspace sizes. In this paper, we examined how accurately Lmmeasures the linear dimensions of airspaces from histological sections and a variety of computer-generated test images. To this end, we developed an automated method for measuring linear intercepts from digitized images of tissue sections and calculate Lmas their mean. We examined how the shape of airspaces and the variability of their sizes influence Lmas well as the distribution of linear intercepts. We found that for a relatively homogeneous enlargement of airspaces, Lmwas a reliable index for detecting emphysema. However, in the presence of spatial heterogeneities with a large variability of airspace sizes, Lmdid not significantly increase and sometimes even decreased compared to its value in normal tissue. We also developed an automated method for measuring the area and computed an equivalent diameter of each individual airspace that is independent of shape. Finally, we introduced new indexes based on the moments of diameter that we found to be more reliable than Lmto characterize airspace enlargement in the presence of heterogeneities.
Design Assumptions by ‘Adult’ Designers versus ‘Child’ User Behaviour
Authors: Ramachandran Sandhya 
Published: March 2006

Instructional theories postulate that learning is most effective when the learning environment is friendly, non-threatening and attractive to the child. However, designing fun-based interactivity to deliver serious educational content is quite a challenge. Sudiksha has designed and developed a series of multilingual CD-ROMs in collaboration with not-for-profit organizations. The objectives of these are to make learning fun in government schools in India. The titles are custom designed to suit the school curricula; the courses are socio-culturally relevant to an Indian audience. The crux of designing courses for schools is that we are ‘adults’ designing content for children. Our panel of design advisers usually consists of pedagogy experts, psychologists and teachers. But the child-user is as dynamic as the medium and more. The user who learns on the run makes our solutions obsolete at a rapid pace. We often take pulse checks to figure out if we are on track with our solutions and our findings are often surprising. The findings of one such study are elaborated here.
Petrogenesis of anorogenic peralkaline granitic complexes from eastern Egypt
Authors: Abdel-Rahman A. M. 
Published: March 2006

AbstractThe Pan-African orogenic shield rocks of eastern Egypt were intruded by several anorogenic within- plate granitic complexes, including Mounts Abu-Kharif and El-Dob. These two massifs were emplaced at the intersection of a fault system and a shear zone. The two massifs are made up of hypersolvus peralkaline granites, consisting essentially of perthitic alkali feldspar (55–65 vol.%), quartz (30–35%), and alkali amphibole (ferrorichterite to arfvedsonite; 5–12%), with accessory zircon, apatite and ilmenite. The rocks are evolved in composition, are relatively enriched in Nb (53–75 ppm), Y (34–72 ppm), Zr (421–693 ppm), Ga (26–29 ppm), and the REE (294–562 ppm), and depleted in Al, Mg, Ca, Sr, Ba and Eu. The REE patterns are sub-parallel, LREE -enriched over HREE , and show prominent negative Eu anomalies. The rocks exhibit mineralogical and chemical traits typical of within-plate A-type granites. Rb-Sr radiometric age dating produced a Cambrian age of 522±21 Ma, and an initial 87Sr/86Sr ratio of 0.7080±0.0042. Thus, the investigated peralkaline granitic rocks were emplaced following the termination of the Pan-African orogeny. The rocks are interpreted to have formed in an extensional tectonic environment during a phase of cooling, relaxation, crustal attenuation, and fracturing of the newly-formed shield.Results of geochemical modelling indicate that the magma may have formed by a large degree of batch partial melting (F = 0.57) of Pan-African calc-alkaline shield rocks, which had been metasomatized possibly by a Na-rich fluid. The volatile flux may have caused fenitization-type reactions along fissures and re-activated Pan-African fractures prior to anatexis, and is considered to have played a role as an important agent of heat transfer. Shear heating, caused possibly by a rapid change in the direction of plate motions beneath eastern Egypt during the Early Palaeozoic, is likely to have produced temperatures necessary for crustal anatexis. The confining pressure must have been released by fissuring of the crust. Magma ascent may have been facilitated by reactivation of pre-existing Pan-African fractures.
Long-range Al,Si equilibrium configuration in Sr feldspar treated at high temperatures
Authors: Benna P. , Bruno E. 
Published: March 2006

AbstractSingle crystals of Sr feldspar (SrAl2Si2O8, space group: I2/c) were treated isothermally in the temperature range between 1410 and 1640°C, in order to determinate the evolution of the Al,Si configurations at equilibrium with thermal treatments. X-ray intensity data collection and structural refinement were performed on the quenched crystals. Significant modifications were observed in the average tetrahedral distances and therefore in Qod values.Two different series of thermal treatments were performed: (1) a crystal of ordered Sr feldspar (Qod= 0.85) was progressively disordered at 1560°C (Qod = 0.82), at 1610°C (Qod = 0.74) and at 1640°C (Qod = 0.69); (2) another crystal with Qod = 0.72 (obtained by annealing a glass at T =1625°C), was ordered at T = 1600° (Qod = 0.75).As already observed in anorthite quenched from 1530°C (Qod = 0.78), also in Sr feldspar, annealing near Tmelt, caused significant disorder in the Al-Si configuration (Qod = 0.69).Observations by transmission electron microscopy show an increase in the average size of the i-type antiphase domains up to 5000Å in the samples quenched from 1640°C, in comparison with samples annealed at 1450°C (∼ 2000 Å). The modifications observed in the Al,Si configurations are due to intradomain disorder.
Crystal symmetry and chemical composition of yukonite: TEM study of specimens collected from Nalychevskie hot springs, Kamchatka, Russia and from Venus Mine, Yukon Territory, Canada
Authors: Nishikawa O. , Okrugin V. , Belkova N. , Saji I. , Shiraki K. , Tazaki K. 
Published: March 2006

AbstractYukonite, a rare arsenic-bearing hydrous mineral, the crystal symmetry and variety in chemical composition of which have so far been insufficiently studied, has been found in the modern deposit of Nalychevskie hot springs in Central Kamchatka, Russia. This is the first finding of yukonite in Eastern Eurasia and Siberia. Yukonite specimens from Nalychevskie hot springs and from Venus Mine in Yukon Territory, Canada, have been investigated using an analytical transmission electron microscope (TEM). Yukonite is a crystalline substance with extremely thin (~5 nm) platy morphology. Yukonite from Venus Mine forms brittle aggregates in which grains are irregularly bent and randomly distributed. At Nalychevskie hot springs, yukonite occurs as single plates, coexisting with some amorphous material of similar composition. Intensity distributions in electron diffraction indicate that most plates of yukonite at Nalychevskie hot springs have orthorhombic symmetry, but some are hexagonal with ahex = 11.3 Å. The orthorhombic cell is C-centred with aorth = √3ahex, borth= ahex. High-resolution images of edge-on mounts indicate that the periodicity normal to the planes is d001=11.2 Å. Yukonite from Nalychevskie hot springs contains anomalously high Si relative to that in yukonite from Venus Mine and that reported previously. Strong negative correlation between As and Si indicates that Si substitutes for As in the structure.
Crystal structure of a synthetic aluminoan tantalian titanite: a reconnaissance study
Authors: Liferovich R. P. , Mitchell R. H. 
Published: March 2006

AbstractA synthetic analogue, Ca(Ti0.6Al0.2Ta0.16Nb0.04)OSiO4, of an aluminoan tantalian titanite previously described from Craveggia pegmatite (Piemonte, Italy) has been prepared by a ceramic synthesis technique and its crystal structure determined by Rietveld analysis of the powder X-ray diffraction pattern. The synthetic Al-Ta-Nb-rich titanite adopts space groupA2/aimplying that substitutions at the single octahedral site destroy the coherence of the off-centering of octahedral chains in the titanite structure resulting in aP21/a →A2/aphase transition. Unit-cell dimensions obtained for the Al-Ta-Nb-rich titanite are:a =7.0649(1) Å;b =8.7187(1) Å;c =6.5701(1) Å; β = 113.755(1)°,V =370.41(1) Å3. The extensive replacement of Ti by Al, Ta and Nb results in a considerable decrease in the distortion of all coordination polyhedra in the structure of this titanite. These structural data suggest that a solid solution CaTi1-x(Alx/2[Ta,Nb]x/2)OSiO4(0 ≤x≤ 0.4) adopting the titanite structure might exist.
Kalungaite, PdAsSe, a new platinum-group mineral from the Buraco do Ouro gold mine, Cavalcante, Goiás State, Brazil
Authors: Botelho N. F. , Moura M. A. , Peterson R. C. , Stanley C. J. , Silva D. V. G. 
Published: March 2006

AbstractKalungaite, PdAsSe, is a new mineral discovered in the Buraco do Ouro gold mine, Cavalcante town, Goiás State, Brazil. It occurs in a quartz-muscovite mylonite, related to a peraluminous granite, in platy anhedral aggregates along foliation planes. Associated ore minerals are gold, chalcopyrite, bohdanowiczite, an unnamed Pb-Bi-Se-S mineral, clausthalite, guanajuatite, stibiopalladinite, sperrylite and padmaite. Gangue minerals are muscovite, quartz and rare tourmaline and magnetite. Kalungaite is lead-grey, has a metallic lustre, a black streak and is brittle with uneven fracture. No cleavage was observed. The mineral has a micro-indentation hardness of VHN25 = 438 (range of 429–455 kg/mm2 from five indentations). Under reflected light, kalungaite is cream, or creamy grey adjacent to gold grains, has no internal reflections and is isotropic. Reflectance values in air (and in oil) are: 47.5 (33.3) at 470 nm, 46.9 (32.6) at 546 nm, 46.8 (32.6) at 589 nm and 48.0 (34.0) at 650 nm. The average of eight electron-microprobe analyses gives: Pd 41.32, As 27.49, Bi 0.35, Sb 1.59, Se 27.67 and S 1.22, total 99.64 wt. %, corresponding to Pd1.006(As0.950Sb0.034Bi0.004)Σ0.988(Se0.908S0.099)Σ1.007Kalungaite is cubic, space group Pa, a = 6.089(4) Å, V = 225.78 Å3, Z = 4. Dcalc is 7.59 g/cm3. The strongest seven X-ray powder-diffraction lines [d in Å(I)(hkl )] are: 3.027(75)(002), 1.838(100)(113), 1.172(95)(115, 333), 1.077(80)(044, 144, 334), 0.988(70)(116, 235, 253), 0.929(90)(335) and 0.918(70)(226). Kalungaite is interpreted as having formed from hydrothermal fluids of granitic origin, during syn-emplacement shearing and alteration, producing an unusual gold-platinum-group element deposit.