bluuebunny/crossref_metadata_2025 huggingface dataset:
The association between female genital mutilation and intimate partner violence
Authors: Salihu HM , August EM , Salemi JL , Weldeselasse H , Sarro YS , Alio AP
Published: August 2012

Please cite this paper as: Salihu H, August E, Salemi J, Weldeselasse H, Sarro Y, Alio A. The association between female genital mutilation and intimate partner violence. BJOG 2012;119:1597–1605.

Objective  To determine whether female genital mutilation (FGM) is a risk factor for intimate partner violence (IPV) and its subtypes (physical, sexual and emotional).

Design  Population‐based cross‐sectional study.

Setting  The study used the 2006 Demographic and Health Survey (DHS) conducted in Mali.

Population  A total of 7875 women aged 15–49 years who responded to the domestic violence and female circumcision modules in the 2006 administration of the DHS in Mali.

Methods  Multivariable logistic regression was used to compute adjusted odds ratios (aOR) and 95% confidence intervals (CI) to measure risk for IPV.

Main outcome measures  The outcomes of interest were IPV and its subtypes.

Results  Women with FGM were at heightened odds of IPV (aOR 2.71, 95% CI 2.17–3.38) and IPV subtypes: physical (aOR 2.85, 95% CI 2.22–3.66), sexual (aOR 3.24, 95% CI 1.80–5.82), and emotional (aOR 2.28, 95% CI 1.68–3.11). The odds of IPV increased with ascending FGM severity (P for trend <0.0001). The most elevated odds were observed among women with severe FGM, who were nearly nine times as likely to experience more than one IPV subtype (aOR 8.81, 95% CI 5.87–13.24).

Conclusions  Study findings underscore the need for multi‐tiered strategies, incorporating policy and education, to reduce FGM and IPV, potentially improving the holistic health and wellbeing of Malian women.
Isolated dorsal root ganglion neurones inhibit receptor‐dependent adenylyl cyclase activity in associated glial cells
Authors: Ng KY , Yeung BHS , Wong YH , Wise H
Published: August 2012

Background and Purpose

Hyper‐nociceptive PGE2 EP4 receptors and prostacyclin (IP) receptors are present in adult rat dorsal root ganglion (DRG) neurones and glial cells in culture. The present study has investigated the cell‐specific expression of two other Gs‐protein coupled hyper‐nociceptive receptor systems: β‐adrenoceptors and calcitonin gene‐related peptide (CGRP) receptors in isolated DRG cells and has examined the influence of neurone–glial cell interactions in regulating adenylyl cyclase (AC) activity.

Experimental Approach

Agonist‐stimulated AC activity was determined in mixed DRG cell cultures from adult rats and compared with activity in DRG neurone‐enriched cell cultures and pure DRG glial cell cultures.

Key Results

Pharmacological analysis showed the presence of Gs‐coupled β2‐adrenoceptors and CGRP receptors, but not β1‐adrenoceptors, in all three DRG cell preparations. Agonist‐stimulated AC activity was weakest in DRG neurone‐enriched cell cultures. DRG neurones inhibited IP receptor‐stimulated glial cell AC activity by a process dependent on both cell–cell contact and neurone‐derived soluble factors, but this is unlikely to involve purine or glutamine receptor activation.

Conclusions and Implications

Gs‐coupled hyper‐nociceptive receptors are readily expressed on DRG glial cells in isolated cell cultures and the activity of CGRP, EP4 and IP receptors, but not β2‐adrenoceptors, in glial cells is inhibited by DRG neurones. Studies using isolated DRG cells should be aware that hyper‐nociceptive ligands may stimulate receptors on glial cells in addition to neurones, and that variable numbers of neurones and glial cells will influence absolute measures of AC activity and affect downstream functional responses.
Polymetamorphism in the mainland Lewisian complex, NW Scotland – phase equilibria and geochronological constraints from the Cnoc an t’Sidhean suite
Authors: ZIRKLER A. , JOHNSON T. E. , WHITE R. W. , ZACK T.
Published: August 2012

The metamorphic evolution of rocks cropping out near Stoer, within the Assynt terrane of the central region of the mainland Lewisian complex of NW Scotland, is investigated using phase equilibria modelling in the NCKFMASHTO and MnNCKFMASHTO model systems. The focus is on the Cnoc an t’Sidhean suite, garnet‐bearing biotite‐rich rocks (brown gneiss) with rare layers of white mica gneiss, which have been interpreted as sedimentary in origin. The results show that these rocks are polymetamorphic and experienced granulite facies peak metamorphism (Badcallian) followed by retrograde fluid‐driven metamorphism (Inverian) under amphibolite facies conditions. The brown gneisses are inferred to have contained an essentially anhydrous granulite facies peak metamorphic assemblage of garnet, quartz, plagioclase and ilmenite (±rutile, K‐feldspar and pyroxene) with biotite, hornblende, muscovite, chlorite and/or epidote as hydrous retrograde minerals. P–T constraints imposed by phase equilibria modelling imply conditions of 13–16 kbar at >900 °C for the Badcallian granulite facies metamorphic peak, consistent with the field evidence for partial melting in most lithologies. The white mica gneiss comprises a muscovite‐dominated matrix containing porphyroblasts of staurolite, corundum, kyanite and rare garnet. Previous studies have suggested that staurolite, corundum, kyanite and muscovite all grew at the granulite facies peak, with partial melting and melt loss producing a highly aluminous residue. However, at the inferred peak P–T conditions, staurolite and muscovite are not predicted to be stable, suggesting they are retrograde phases that grew during amphibolite facies retrograde metamorphism. The large proportion of mica suggests extensive H2O‐rich fluid‐influx, consistent with the retrograde growth of hornblende, biotite, epidote and chlorite in the brown gneisses. P–T conditions of 5.0–6.5 kbar at 520–550 °C are derived for the Inverian event. In situ dating of zircon from samples of the white mica gneiss yield apparent ages that are difficult to interpret. However, the data are permissive of granulite facies (Badcallian) metamorphism having occurred at c. 2.7–2.8 Ga with subsequent fluid driven (Inverian) retrogression at c. 2.5–2.6 Ga, consistent with previous interpretations.
Adolescent Rearing Conditions Influence the Relationship Between Initial Anxiety‐Like Behavior and Ethanol Drinking in Male Long Evans Rats
Authors: Chappell Ann M. , Carter Eugenia , McCool Brian A. , Weiner Jeff L.
Published: August 2012

Background

Rodent studies have demonstrated that adolescent social isolation results in many behavioral perturbations, including increases in anxiety‐like behaviors. Socially isolated (SI) rats have also been shown to self‐administer greater amounts ethanol (EtOH) in some, but not all, studies. Here, we tested whether juvenile social isolation increases EtOH drinking using an intermittent procedure that engenders relatively high intake in normally reared animals. We also compared the behavioral phenotype of rats reared under social isolation or group‐housed conditions with adult rats housed under conditions commonly used in EtOH‐drinking studies.

Methods

Male Long Evans rats were procured immediately postweaning and were group housed for 1 week. Subjects were then randomly divided into 2 groups: SI rats, housed individually for 6 weeks and group‐housed (GH) rats (4/cage). A third group was procured as young adults and was housed individually upon arrival for 1 week (standard housing condition). Rats were then tested in a plus‐maze and novelty assay, and then, all subjects were singly housed and EtOH drinking was assessed.

Results

SI rats displayed increased anxiety‐like behaviors on the plus‐maze, a greater locomotor response to a novel environment, and increased EtOH intake, relative to GH rats. Age‐matched standard housed (STD) rats exhibited an anxiety‐like behavioral profile on the plus‐maze that was similar to SI, and not GH rats, and also drank EtOH at levels comparable with SI subjects. In addition, anxiety‐like behavior on the plus‐maze correlated with intermittent EtOH intake in SI and GH rats.

Conclusions

These data further support the validity of the rodent juvenile social isolation model for studies directed at elucidating behavioral and neurobiological mechanisms linking anxiety and EtOH drinking. These findings further suggest that housing conditions commonly employed in rodent drinking studies may recapitulate the anxiety‐like and EtOH‐drinking phenotype engendered by a juvenile social isolation procedure.
Array‐Based Profiling of DNA Methylation Changes Associated with Alcohol Dependence
Authors: Zhang Huiping , Herman Aryeh I. , Kranzler Henry R. , Anton Raymond F. , Zhao Hongyu , Zheng Wei , Gelernter Joel
Published: August 2012

Background

Epigenetic regulation through DNA methylation may influence vulnerability to numerous disorders, including alcohol dependence (AD).

Methods

Peripheral blood DNA methylation levels of 384 CpGs in the promoter regions of 82 candidate genes were examined in 285 African Americans (AAs; 141 AD cases and 144 controls) and 249 European Americans (EAs; 144 AD cases and 105 controls) using Illumina GoldenGate Methylation Array assays. Association of AD and DNA methylation changes was analyzed using multivariate analyses of covariance with frequency of intoxication, sex, age, and ancestry proportion as covariates. CpGs showing significant methylation alterations in AD cases were further examined in a replication sample (49 EA cases and 32 EA controls) using Sequenom's MassARRAY EpiTYPER technology.

Results

In AAs, 2 CpGs in 2 genes (GABRB3 and POMC) were hypermethylated in AD cases compared with controls (p ≤ 0.001). In EAs, 6 CpGs in 6 genes (HTR3A, NCAM1, DRD4, MBD3, HTR2B, and GRIN1) were hypermethylated in AD cases compared with controls (p ≤ 0.001); CpG cg08989585 in the HTR3A promoter region showed a significantly higher methylation level in EA cases than in EA controls after Bonferroni correction (p = 0.00007). Additionally, methylation levels of 6 CpGs (including cg08989585) in the HTR3A promoter region were analyzed in the replication sample. Although the 6 HTR3A promoter CpGs did not show significant methylation differences between EA cases and EA controls (p = 0.067 to 0.877), the methylation level of CpG cg08989585 was nonsignificantly higher in EA cases (26.9%) than in EA controls (18.6%; p = 0.139).

Conclusions

The findings from this study suggest that DNA methylation profile appears to be associated with AD in a population‐specific way and the predisposition to AD may result from a complex interplay of genetic variation and epigenetic modifications.
Complete paternal uniparental isodisomy for Chromosome 2 revealed in a parentage testing case
Authors: Ou Xueling , Liu Chao , Chen Suqin , Yu Jianfeng , Zhang Yinming , Liu Sujuan , Sun Hongyu
Published: August 2012

BACKGROUND: Uniparental disomy (UPD) is a rare cytogenetic event that has previously been reported mostly via genetic analysis of patients with phenotypes of recessive diseases. The incidence of UPD of any chromosome is estimated to be approximately1:3500 live births.

CASE REPORT: In a case of disputed paternity involving a phenotypically normal male child, mother–child exclusions were observed at five short tandem repeat markers, which were all located on Chromosome 2. Ten additional dinucleotide repeat markers spanning both arms of Chromosome 2 were investigated. The results revealed that the child was homozygous for all markers tested with all alleles originating from a single paternal Chromosome 2, which was consistent with paternal UPD for Chromosome 2.

CONCLUSION: This case and other previous reports demonstrate that UPD poses a high risk for false exclusion and incorrect expert opinion. Furthermore, this case highlights that a conclusion of exclusion of paternity or maternity should not be postulated if multiple genetic incompatibilities are located on the same chromosome because of the occurrence of UPD.
Bioavailability and Antioxidant Activity of Black Chokeberry (Aronia melanocarpa) Polyphenols: in vitro and in vivo Evidences and Possible Mechanisms of Action: A Review
Authors: Denev Petko N. , Kratchanov Christo G. , Ciz Milan , Lojek Antonin , Kratchanova Maria G.
Published: August 2012

Abstract:  Black chokeberry (Aronia melanocarpa) is a distinctive berry with a high content of polyphenol compounds and possesses one of the highest in vitro antioxidant activities among fruits. The bioavailability of aronia polyphenols seems to be low, but there is ample evidence for chokeberry health benefits including antidiabetic, cardioprotective, hepatoprotective, antimutagenic, and anticarcinogenic effects. This review presents the available information for the bioavailability and antioxidant activity of chokeberry polyphenols and explains the possible mechanisms of action in vivo in the prevention and treatment of oxidative stress‐related diseases. The review shows the available data for chokeberry antioxidant activity in vitro, in isolated cells and cell lines, and in vivo, in both human subjects and animals. It is evident that in vivo antioxidant action of chokeberry extends far beyond radical scavenging and includes suppression of reactive oxygen and nitrogen species formation, inhibition of prooxidant enzymes, restoration of antioxidant enzymes, and probably cellular signaling to regulate the level of antioxidant compounds and enzymes. The original contribution of this work is that it compiles the available information up to date and outlines the gaps and future directions in the assessment of chokeberry antioxidant action in vivo.
Heparin‐grafted dialysis membrane allows minimal systemic anticoagulation in regular hemodialysis patients: A prospective proof‐of‐concept study
Authors: Kessler Michèle , Gangemi Concetta , Gutierrez Martones Alberto , Lacombe Jean‐Louis , Krier‐Coudert Marie‐Jeanne , Galland Roula , Kielstein Jan T. , Moureau Frédérique , Loughraieb Nathalie
Published: August 2012

This prospective, multicenter, proof‐of‐concept study aimed to evaluate the possibility to reduce the ordinary heparin dose and the systemic anti‐Xa activity during hemodialysis (HD) sessions using a new heparin‐grafted HD membrane. In 45 stable HD patients, the use of a heparin‐grafted membrane with the ordinary heparin dose was followed by a stepwise weekly reduction of dose. Reduction was stopped when early signs of clotting (venous pressure, quality of rinse‐back) occurred during two out of three weekly HD sessions. Heparin dose was decreased for 67% of patients resulting in the lowering of these patients' anti‐Xa activity by 50%. Dose reductions were achieved with both types of heparin (low‐molecular‐weight heparin: 64 ± 14 to 35 ± 12 IU/kg, P < 0.0001; unfractionated heparin: 82 ± 18 to 46 ± 13 IU/kg, P < 0.0001) resulting in a decrease of anti‐Xa activity at dialysis session end (low‐molecular‐weight heparin: 0.51 ± 0.25 to 0.25 ± 0.11 IU/mL, P < 0.0001; unfractionated heparin: 0.28 ± 0.23 to 0.13 ± 0.07 IU/mL, P < 0.0001). Failure to further decrease heparin dose was related to signs of clotting in blood lines (57% of sessions), in dialyzer (9%), or both (34%). Significant reduction of heparin dose and anti‐Xa activity at the end of HD sessions was possible in stable HD patients using heparin‐grafted membrane. HD patients who require low anti‐Xa activity at the end of HD sessions might benefit from a heparin‐grafted membrane to reduce bleeding risk and other heparin adverse events.
What determines skin sensitization potency–myths, maybes and realities. Part 1. The 500 molecular weight cut‐off
Authors: Roberts David W. , Mekenyan Ovanes G. , Dimitrov Sabcho D. , Dimitrova Gergana D.
Published: August 2012

Background. It is widely accepted that there is a molecular weight (MW) cut‐off of 500, such that single chemicals with MWs higher than 500 cannot be skin sensitizers. If true, this could serve as a useful principle for designing non‐sensitizing chemicals.

Objectives. To assess whether the 500 MW cut‐off is a myth or a reality.

Methods. A database of 699 chemicals tested for skin sensitization in guinea pigs or mice was analysed to establish the number of tested chemicals with MW > 500, and to establish whether any of these were sensitizers.

Results. Only 13 (2%) of the 699 chemicals in the database have MW > 500. Of the 13 tested compounds with MW > 500 in the database, five are sensitizers and eight are non‐sensitizers.

Conclusions. The 500 MW cut‐off for skin sensitization is a myth, probably derived from the widespread misconception that ability to efficiently penetrate the stratum corneum is a key determinant of sensitization potency. The scarcity of sensitizers with MW > 500 simply reflects the general scarcity of chemicals with MW > 500.
Opportunistic filamentous mycoses: aspergillosis, mucormycosis, phaeohyphomycosis and hyalohyphomycosis
Authors: Perusquía‐Ortiz Ana María , Vázquez‐González Denisse , Bonifaz Alexandro
Published: August 2012

Opportunistic filamentous mycoses are widely distributed all over the world. They are rarely observed in Europe but are common in developing countries. The most common are the aspergilloses (due to Aspergillus spp.) mostly in neutropenia and immunosuppression; the mucormycoses characterized by rapid progression in patients with diabetic ketoacidosis; the phaeohyphomycoses due to pigmented fungi causing either a mild superficial or a very serious deep disease and the hyalohyphomycoses due to hyaline filamentous fungi (Fusarium spp., Pseudallescheria spp., Scopulariopsis spp.). Cutaneous manifestations are usually secondary to dissemination from pulmonary or visceral disease; primary cases are less frequent and due to direct inoculation into the skin.

We review epidemiological, clinical, diagnostic, and therapeutic data on the four most important opportunistic filamentous mycoses: aspergillosis, mucormycosis, phaeohyphomycosis and hyalohyphomycosis.
The zebrafish as a model for paediatric diseases
Authors: Lohi Olli , Parikka Mataleena , Rämet Mika
Published: August 2012

The rapid increase in information about genes and their associations with human diseases has highlighted the need for model organisms suitable for genetic manipulation and drug testing. The zebrafish is a valuable vertebrate animal model that offers many advantages, including the relative ease of husbandry and genetic manipulation and the capacity for high‐throughput screens. In this review, we describe the zebrafish as a model for paediatric diseases, with particular emphasis on haematopoietic and infectious diseases.

Conclusion:  The zebrafish has become an established vertebrate model in which to elucidate the molecular mechanisms of various human diseases.
Phloem‐Mobile Aux/IAA Transcripts Target to the Root Tip and Modify Root ArchitectureF
Authors: Notaguchi Michitaka , Wolf Shmuel , Lucas William J.
Published: August 2012

In plants, the phloem is the component of the vascular system that delivers nutrients and transmits signals from mature leaves to developing sink tissues. Recent studies have identified proteins, mRNA, and small RNA within the phloem sap of several plant species. It is now of considerable interest to elucidate the biological functions of these potential long‐distance signal agents, to further our understanding of how plants coordinate their developmental programs at the whole‐plant level. In this study, we developed a strategy for the functional analysis of phloem‐mobile mRNA by focusing on IAA transcripts, whose mobility has previously been reported in melon (Cucumis melo cv. Hale's Best Jumbo). Indoleacetic acid (IAA) proteins are key transcriptional regulators of auxin signaling, and are involved in a broad range of developmental processes including root development. We used a combination of vasculature‐enriched sampling and hetero‐grafting techniques to identify IAA18 and IAA28 as phloem‐mobile transcripts in the model plant Arabidopsis thaliana. Micro‐grafting experiments were used to confirm that these IAA transcripts, which are generated in vascular tissues of mature leaves, are then transported into the root system where they negatively regulate lateral root formation. Based on these findings, we present a model in which auxin distribution, in combination with phloem‐mobile Aux/IAA transcripts, can determine the sites of auxin action.
Wellbore‐Wall Compression Effects on Monitored Groundwater Levels and Qualities
Authors: Eguchi S. , Sawamoto M. , Shiba M. , Iiyama I. , Hasegawa S.
Published: August 2012

The effects of wellbore‐wall compression from rough excavation on monitored groundwater levels and qualities under natural hydraulic gradient conditions were investigated in a shallow clayey Andisol aquifer. Nine wellbores reaching the underlying aquitard at about 2.6‐m depth were constructed by dynamic cone penetrometry to mimic rough wellbore construction. Five of these were constructed under wet aquifer soil conditions and the remaining four under dry conditions. A 15‐month period monitoring showed that the groundwater levels in the wellbores constructed under wet conditions responded significantly in retard of, and in narrower ranges than, those constructed under dry conditions. The wellbore‐wall hydraulic conductivities at the former wellbores were calculated to be more than one to two orders of magnitude lower than those at the latter ones. Furthermore, remarkable nitrate removal attributable to the occurrence of a heterotrophic denitrification was observed in one of the former wellbores. In contrast, the groundwater levels and qualities in the latter wellbores appeared to be generally similar to those monitored in the conventional soil coring and augering‐derived wellbores. Our results suggest that the wellbore‐wall compression induced by rough excavation under wet and soft aquifer soil conditions leads to a substantial decrease in the wellbore‐wall hydraulic conductivity, which in turn can lead to unreliable groundwater levels and qualities. This problem can occur in clayey Andisols whenever the aquifer soil is wet; however, the problem can be largely avoided by constructing the wellbore under dry and hard aquifer soil conditions.
Skin Cancer Risks Avoided by the Montreal Protocol—Worldwide Modeling Integrating Coupled Climate‐Chemistry Models with a Risk Model for UV
Authors: van Dijk Arjan , Slaper Harry , den Outer Peter N. , Morgenstern Olaf , Braesicke Peter , Pyle John A. , Garny Hella , Stenke Andrea , Dameris Martin , Kazantzidis Andreas , Tourpali Kleareti , Bais Alkiviadis F.
Published: August 2012

The assessment model for ultraviolet radiation and risk “AMOUR” is applied to output from two chemistry‐climate models (CCMs). Results from the UK Chemistry and Aerosols CCM are used to quantify the worldwide skin cancer risk avoided by the Montreal Protocol and its amendments: by the year 2030, two million cases of skin cancer have been prevented yearly, which is 14% fewer skin cancer cases per year. In the “World Avoided,” excess skin cancer incidence will continue to grow dramatically after 2030. Results from the CCM E39C‐A are used to estimate skin cancer risk that had already been inevitably committed once ozone depletion was recognized: excess incidence will peak mid 21st century and then recover or even super‐recover at the end of the century. When compared with a “No Depletion” scenario, with ozone undepleted and cloud characteristics as in the 1960s throughout, excess incidence (extra yearly cases skin cancer per million people) of the “Full Compliance with Montreal Protocol” scenario is in the ranges: New Zealand: 100–150, Congo: −10–0, Patagonia: 20–50, Western Europe: 30–40, China: 90–120, South‐West USA: 80–110, Mediterranean: 90–100 and North‐East Australia: 170–200. This is up to 4% of total local incidence in the Full Compliance scenario in the peak year.
Using systematic conservation planning to minimize REDD+ conflict with agriculture and logging in the tropics
Authors: Venter Oscar , Possingham Hugh P. , Hovani Lex , Dewi Sonya , Griscom Bronson , Paoli Gary , Wells Phillip , Wilson Kerrie A.
Published: August 2012

This article describes the first application of systematic conservation planning for prioritizing REDD+ (reducing emissions from deforestation and forest degradation) strategies and agricultural expansion. For a REDD+ program in Indonesian Borneo, we find that the most cost‐effective way to reduce forest‐based emissions by 25% is to better manage protected areas and logging concessions. A more ambitious emissions reduction target would require constraining agricultural expansion and logging, which incurs opportunity costs. We discover, however, that these impacts can be mitigated by relocating oil palm (Elaeis guineensis) agricultural leases to areas that store, on average, 130 tons less carbon per hectare and are 8% more productive for oil palm. This reduces the costs of meeting REDD+ targets, avoids conflict with agriculture, and has the unanticipated effect of minimizing impacts on logging. Our approach presents a transparent and defensible method for prioritizing REDD+ locations and strategies in a way that minimizes development trade‐offs and promotes implementation success.
CHANGE PROCESS DURING SYNCHRONISED CONVERSION TO A ONCE‐MONTHLY ERYTHROPOIESIS‐STIMULATING AGENT (ESA) ADMINISTRATION AT A SINGLE SATELLITE HAEMODIALYSIS UNIT
Authors: Chow Josephine Sau Fan , Rayment Glenda , Britos Veronica , Cleland Bruce , Suranyi Michael
Published: August 2012

Background: There are currently no published data on the impact of changes to practice caused by introducing coordinated once‐monthly erythropoiesis‐stimulating agent (ESA) administration.

Objective: This study aimed to measure staff satisfaction during and after ESA synchronisation within a single satellite haemodialysis unit.

Design: A quantitative survey using a Likert scale was distributed to dialysis nurses pre‐synchronisation and during follow‐up at three and nine months post‐synchronisation. Secondary outcomes included monitoring of haemoglobin (Hb) levels.

Results: A total of 19 respondents completed the surveys. By nine months post‐synchronisation, most nurses responded that ESA synchronisation was not a time‐consuming task, did not increase their workload, had saved them time and was simpler for the unit. Additionally, most nurses reported that they had coped well with the change and that they wanted ESA synchronisation to be permanently introduced. At 8 months post‐synchronisation, 53.3% of patients had an Hb level >11 g/dl and <12g/dl.

Conclusion: Changes to practice resulting from ESA synchronisation did not appear to negatively impact nurse workplace satisfaction.
Structural outer rim of Chesapeake Bay impact crater: Seismic and bore hole evidence
Authors: Poag C. Wylie
Published: August 2012

Abstract— Nine seismic‐reflection profiles and four continuous core holes define the gross structural and stratigraphic framework of the outer rim of the Chesapeake Bay impact crater. The rim is manifested as a 90 km diameter ring of terraced normal‐fault blocks, which forms a ∼320 m–1200 m high rim escarpment. The top of the rim escarpment is covered by a 20 m–30 m thick ejecta blanket. The escarpment encircles a flat‐floored annular trough, which is partly filled with an ∼250 m thick breccia lens (Exmore breccia). The Exmore breccia overlies a 200 m–800 m thick interval of slumped sedimentary megablocks, which, in turn, rests on crystalline basement rocks. All postimpact strata (upper Eocene to Quaternary) sag structurally into the annular trough, and most units also thicken as they cross the rim into the crater. Postimpact compaction and subsidence of the Exmore breccia have created extensive normal faulting in overlying strata.
Noble gas study of a philippinite with an unusually large bubble
Authors: Matsuda Jun‐ichi , Maruoka Teruyuki , Pinti Daniele Luigi , Koeberl Christian
Published: August 2012

Abstract— A philippinite with a large bubble (volume ⋍5 cm3) was crushed in a specifically constructed device under vacuum. The total pressure, the major gas components, and the concentration and the isotopic composition of noble gases in the trapped gas were measured. The total gas pressure was found to be low, ∼10−4 atm. Compared to terrestrial atmosphere, the abundances of He and Ne are considerably more enriched than the concentrations of the heavy noble gases. Unusually high 20Ne/22Ne and 21Ne/22Ne ratios were measured in the bubble gas. These ratios are higher than values expected for any steady state process and are interpreted to reflect very fast nonsteady state diffusion in the early stages of tektite formation.
A transmission electron microscopy (TEM) investigation of opaque phases in shocked chondrites
Authors: Joreau Pascal , Leroux Hugues , Doukhan Jean‐Claude
Published: August 2012

Abstract— Shock defects in the most common silicate minerals of chondrites (olivine, pyroxenes and feldspars) have been investigated in detail, but there have been almost no studies of the shock defects in other components, like metal and sulfide. This probably stems from the fact that these latter phases are opaque in the optical microscope. The same reason explains why veins and melt pockets, which are constituted of microcrystalline or glassy phases (i.e., isotropic) are also poorly documented. We have investigated such phases by analytical transmission electron microscopy (ATEM) in two shocked chondrites, Tenham (L6) and Gaines County (H5).

We have characterized shock defects in troilite very similar to those occurring in silicates (i.e., a mosaic texture and sets of straight and very narrow, ⋍10 nm, lamellae of amorphized FeS).

There are many small regions in shocked chondrites that are composed of very fine grained (⋍1 μm) mixtures of metal and sulfide or of various silicates. They must result from local melting followed by a rapid cooling that prevented grain growth. We have determined the chemical compositions and the volume proportions of the tiny grains in these veins and melt pockets, which has allowed their temperature and pressure (T, P) history to be partially deciphered.

Finally, we have observed a dense network of very narrow fractures (down to 10 nm) in the olivine and enstatite grains. These fractures are systematically filled with an amorphous (or cryptocrystalline) material that stems from the melt pockets and was injected when the fractures were opened by the rarefaction wave. This material was then quenched at the contact with the colder crystalline rims.
Mantle material in the main belt: Battered to bits?
Authors: BURBINE Thomas H. , MEIBOM Anders , BINZEL Richard P.
Published: August 2012

Abstract— The complete (or near complete) differentiation of a chondritic parent body is believed to result in an object with an Fe‐Ni core, a thick olivine‐dominated mantle and a thin plagioclase/pyroxene crust. Compositional groupings of iron meteorites give direct evidence that at least 60 chondritic parent bodies have been differentiated and subsequently destroyed. A long standing problem has been that our meteorite collections, and apparently our asteroid observations as well, show a great absence of olivine‐dominated metal‐free mantle material. While the basaltic achondrites (HED meteorites) represent metal‐free pyroxene‐dominated crustal samples, the isotopic and geochemical evidence implies that this class is derived from only one parent body (perhaps Vesta). Thus the meteoritic (and perhaps astronomical) evidence also suggests a great absence of crustal material resulting from the collisional disruption of numerous parent bodies.

One explanation for the rarity of olivine‐dominated metal‐free and basaltic asteroids that fits all the available evidence is that all differentiated parent bodies, with the exception of Vesta, were either disrupted or had their crusts and mantles stripped very early in the age of the solar system. The resulting basaltic and olivine‐dominated metal‐free fragments were continually broken down until their sizes dropped at least below our current astronomical measurement limit (∼5–10 km for inner‐belt objects) and perhaps completely comminuted such that meteorite samples are no longer delivered. Because of their greater strengths and longer survival time in interplanetary space, only the iron and the stony‐iron meteorites remain as the final tracers of this differentiation and collisional history. However, other scenarios remain plausible such as those which invoke “space weathering” processes that effectively disguise the distinctive basaltic and olivine spectra of possible remnant crustal and mantle material within the main asteroid belt.
Evidence in a glassy cosmic spherule from Antarctica for grazing incidence encounters with the Earth's atmosphere
Authors: GENGE Matthew J. , GRADY Monica M. , HUTCHISON Robert
Published: August 2012

Abstract— Cosmic dust accreted by the Earth can be extensively reprocessed during atmospheric encounters. The textures and compositions of reprocessed material provide important constraints by which the processes affecting extraterrestrial matter in the Earth's atmosphere can be better understood. Here we report results on an unusual Antarctic glassy cosmic spherule that demonstrates strong textural evidence for at least two grazing incidence encounters with the Earth's atmosphere prior to final reentry. The particle consists of a central glassy core with four peripheral glass lobes that transect a silicate particle rim. The texture of the particle confirms previous theoretical speculations that some high velocity, low incidence angle interplanetary particles experience numerous encounters with the Earth's atmosphere and also indicates that micrometeorites demonstrating multiple melting episodes should be interpreted with caution.
Processing of chondritic and planetary material in spiral density waves in the nebula
Authors: WOOD J. A.
Published: August 2012

Abstract— A widely held view of nebular evolution is that during the ∼0.5 Ma while interstellar material was collapsing onto the disk, the latter grew in mass to the point of gravitational instability. It responded to this by losing axial symmetry, growing spiral arms that had the capacity to tidally redistribute disk mass (inward) and angular momentum (outward) and prevent further increase in the disk/protosun mass ratio. The spiral arms (density waves) rotated differently than the substance of the nebula, and in some parts of the disk, nebular material may have encountered the arms at supersonic velocities. The disk gas, and solid particles entrained in it, would have been heated to some degree when they passed through shock fronts at the leading edges of the spiral arms. The present paper proposes this was the energetic nebular setting or environment that has long been sought, in which the material now in the planets and chondritic meteorites was thermally processed.
Impact microcraters on an Australasian microtektite
Authors: Prasad M. Shyam , Sudhakar M.
Published: August 2012

Abstract— Microcraters attributable to impact have been discovered on an Australasian microtektite from a core in the Central Indian Basin. The craters resemble lunar microcraters and those generated during impact experiments. The largest crater here, which has a welded promontory, is unique. The projectiles that produced the impacts defined varying trajectories and velocities, ranging from hypervelocity to low velocity (a few 10 m/s). The impacts took place while the microtektite was in flight at an elevated target temperature. This is the first observation of the microimpact phenomenon on a microtektite.
Red Wing Creek structure, North Dakota: Petrographical and geochemical studies, and confirmation of impact origin
Authors: Koeberl Christian , Reimold Wolf Uwe , Brandi Dion
Published: August 2012

Abstract The 9 km diameter Red Wing Creek structure, North Dakota, is located within the oil‐rich Williston Basin at 47°36′N and 103°33′W. Earlier geophysical studies indicated that this subsurface structure has a central uplift, surrounded by an annular crater moat, and a raised rim. Breccias were encountered during drilling between ∼2000 and 2800 m depth in the central uplift area, and the presence of shatter cone fragments in drill core samples was suggested to indicate an impact origin of the Red Wing Creek structure. We studied the petrographic and geochemical characteristics of samples of well cuttings from two boreholes at the center of the structure: the True Oil 22–27 Burlington Northern and True Oil 11–27 Burlington Northern wells. We found planar deformation features (PDFs) in quartz with up to three sets of different crystallographic orientations in sandstone‐ and siltstone‐dominated samples from the True Oil 11–27 borehole. U‐stage measurements of the crystallographic orientations of the PDFs showed the occurrence of the shock‐characteristic (0001), and orientations, with a dominance of (0001) and orientations. The relative frequencies of the orientations indicate a shock pressure of at least 12–20 GPa. These results provide unambiguous evidence for shock metamorphism at Red Wing Creek and confirm that the structure was formed by impact.
On the relationship between the Apollo 16 ancient regolith breccias and feldspathic fragmental breccias, and the composition of the prebasin crust in the Central Highlands of the Moon
Authors: Korotev Randy L.
Published: August 2012

Abstract Two types of texturally and compositionally similar breccias that consist largely of fragmental debris from meteorite impacts occur at the Apollo 16 lunar site: Feldspathic fragmental breccias (FFBs) and ancient regolith breccias (ARBs). Both types of breccia are composed of a suite of mostly feldspathic components derived from the early crust of the Moon and mafic impact‐melt breccias produced during the time of basin formation. The ARBs also contain components, such as agglutinates and glass spherules, indicating that the material of which they are composed occurred at the surface of the Moon as fine‐grained regolith prior to lithification of the breccias. These components are absent from the FFBs, suggesting that the FFBs might be the protolith of the ARBs. However, several compositional differences exist between the two types of breccia, making any simple genetic relationship implausible. First, clasts of mafic impact‐melt breccia occurring in the FFBs are of a different composition than those in the ARBs. Also the feldspathic “prebasin” components of the FFBs have a lower average Mg/Fe ratio than the corresponding components of the ARBs; the average composition of the plagioclase in the FFBs is more sodic than that of the ARBs; and there are differences in relative abundances of rare earth elements. The two breccia types also have different provenances: the FFBs occur primarily in ejecta from North Ray crater and presumably derive from the Descartes Formation, while the ARBs are restricted to the Cayley plains. Together these observations suggest that although some type of fragmental breccia may have been a precursor to the ARBs, the FFBs of North Ray crater are not a significant component of the ARBs and, by inference, the Cayley plains. The average compositions of the prebasin components of the two types of fragmental breccia are generally similar to the composition of the feldspathic lunar meteorites. With 30–31% Al2O3, however, they are slightly richer in plagioclase than the most feldspathic lunar meteorites (∼29% Al2O3), implying that the crust of the early central nearside of the Moon contained a higher abundance of highly feldspathic anorthosite than typical lunar highlands, as inferred from the lunar meteorites. The ancient regolith breccias, as well as the current surface regolith of the Cayley plains, are more mafic than (1) prebasin regoliths in the Central Highlands and (2) regions of highlands presently distant from nearside basins because they contain a high abundance (∼30%) of mafic impact‐melt breccias produced during the time of basin formation that is absent from other regoliths.
The Tianlin meteorite
Authors: Bartoschewitz R. , Spettel B.
Published: August 2012

Abstract Chemical data are reported for the Tianlin iron meteorite from south China. The meteorite is classified as a coarse octahedrite of group IA with complete decomposition of cohenite to ferrite and graphite.
The fall of the St‐Robert meteorite
Authors: BROWN Peter , HILDEBRAND Alan R. , GREEN Daniel W. E. , PAGÉ Denis , JACOBS Cliff , REVELLE Doug , TAGLIAFERRI Edward , WACKER John , WETMILLER Bob
Published: August 2012

Abstract The St‐Robert (Québec, Canada) meteorite shower occurred on 1994 June 15 at 0h02m UT accompanied by detonations audible for >200 km from the fireball endpoint. The fireball was recorded by visual observers in Vermont, New York State, New Hampshire, Québec and Ontario as well as by optical and infrared sensors in Earth‐orbit. Penetration to an altitude of 36 km occurred ∼60 km to the northeast of Montreal, where the bolide experienced several episodes of fragmentation. A total of 20 fragments of this H5 chondrite, comprising a total mass of 25.4 kg, were recovered in an ellipse measuring 8 × 3.5 km. One fragment of the shower partially penetrated the aluminum roof of a shed.

Interpretation of the visual and satellite data suggests that the fireball traveled from south‐southwest to north‐northeast, with a slope from the horizontal of 55°–61°. A statistical evaluation of the likely heliocentric orbits for the body prior to collision with the Earth, coupled with theoretical modeling of the entry, suggests an entry velocity in the range of 12.7–13.3 km/s; the meteoroid had moved in a low‐inclination orbit, with orbital perihelion located extremely close to the Earth's orbit.

From satellite optical data, it is found that the photometric mass consumed during the largest detonation is ∼1200 kg. Estimation of the amplitude of the acoustic signal detected by the most distant observer yields a source energy near 0.5 kt TNT equivalent energy, which corresponds to a mass of order 10 metric tonnes. This measure is uncertain to approximately one order of magnitude. Theoretical modeling of the entry of the object suggests a mass near 1600 kg. Cosmogenic radionuclide activities constrain the lower initial mass to be ∼700 kg with an upper limit near 4000 kg. Seismic data possibly associated with the fireball suggest extremely poor coupling between the airwave and the ground.

The total mass estimated to have reached the ground is ∼100 kg (in material comprising >55 g fragments), while the preatmospheric mass is found to be most probably in the range of 1200–2000 kg.
The Meteoritical Bulletin, No. 79, 1996 July: Recently classified specimens in the United States Antarctic Meteorite Collection (1994–1996)*
Authors: Grossman Jeffrey N. , Score Roberta
Published: August 2012

Abstract— The Meteoritical Bulletin No. 79 contains a list of all meteorites classified between 1994 March and 1996 February by the United States' Antarctic meteorite program. The compilation includes available information on classification, mass, weathering, olivine and pyroxene composition, 26Al activities, natural thermoluminescence levels, pairing, collection location, and references to published descriptions for 1761 meteorite specimens. A list of the most significant meteorites in the entire ANSMET collection of 7298 classified specimens is also included.
S‐type asteroids, ordinary chondrites, and space weathering: The evidence from Galileo's fly‐bys of Gaspra and Ida
Authors: CHAPMAN Clark R.
Published: August 2012

Abstract— New observations of the S‐type asteroids Gaspra and Ida, especially, by the Galileo spacecraft demonstrate that a “space weathering” process operates, which modifies the reflectance spectra of fresh material to be redder, straighter, and have shallower absorption bands. The weathering process appears similar to but less potent than that observed on the Moon. It operates in the sense that it would tend to convert spectra of ordinary chondrites (OC) to having the spectral traits of S‐type asteroids. These results appear to resolve the major obstacles of the long standing “S‐type conundrum” about the provenance of ordinary chondrite meteorites. A wide body of recent research, which is reviewed here, builds on previous meteoritical evidence to support a new, developing consensus that the larger S‐type asteroids are a diverse assortment of silicaceous assemblages, which includes the ordinary chrondite parent bodies. Recent fairly realistic laboratory simulations of space weathering processes have changed OC spectra to resemble S‐type spectra. J. F. Bell's highly regarded earlier paradigm that OC parent bodies would be found only among sub‐10 km main‐belt asteroids has been tested by an extensive observational survey by R. Binzel and his proteges; the result is that no small, main‐belt analog for the OCs has been found, not even the somewhat OC‐like object Boznemcová.

This article reviews the history of the S‐type conundrum, which set the stage for Galileo's historic flybys. I review the findings about Gaspra and Ida, including results about their geology, their geophysical structure and probable origins, and about Ida's small moonlet, Dactyl. Density constraints on Ida set by Dactyl's orbit rule out (for Ida, at least) the classic view of S‐types as metallic, stripped cores of differentiated precursor asteroids. New analysis of the Galileo spectral images of Ida is presented that provides strong evidence that space weathering occurs on Ida, and that Ida, and the Koronis family asteroids in general, are plausibly OC‐like in composition. After reviewing 1990s developments on the S‐type conundrum, I advocate a new perspective that the ordinary chondrite parent bodies are among the S‐type asteroids, a diverse grouping that also contains other silicaceous and silicate/metal assemblages, presumably including various stony‐irons and primitive achondrites represented in meteorite collections; Gaspra may be such a metal‐rich assemblage.
The search for exsolved ferromagnesian olivines: A meteoritic survey
Authors: PETAEV Michail I.
Published: August 2012

Abstract— Olivine grains from selected meteorites (the Springwater pallasite, the Lowicz mesosiderite, the ALH 84025 brachinite, the Krymka LL3 chondrite, and the Calcalong Creek lunar meteorite) and terrestrial rocks (San Carlos forsterite and Rockport fayalite) were studied by optical microscopy and high‐precision electron microprobe analysis. Detailed microprobe traverses revealed regular igneous zoning in the Krymka and Calcalong Creek olivines. Traverses across the San Carlos forsterite grain are flat and display no chemical variations larger than the 2σ range of counting error (±0.2 mol% Fa). Traverses across olivine grains in the ALH 84025, Lowicz, and Springwater meteorites show regular patterns of periodic or wavy chemical variations well exceeding the 2σ uncertainty range. However, no lamellar structure was seen in backscattered electron images. It is suggested that the periodic chemical variations may be due to spinodal decomposition of primary, more or less homogeneous grains. I conclude that the absence of earlier reports of such variations simply means that olivine grains in equilibrated meteorites have not been examined closely enough to detect them.