bluuebunny/crossref_metadata_2025 huggingface dataset:
Researching the use of new technologies (ICTs) in Zimbabwean newsrooms: an ethnographic approach
Authors: Mawindi Mabweazara Hayes
Published: December 2010

This article examines the challenges of deploying ethnography to study the fluid and dispersed processes of ICT use in journalism practice. It draws on the author’s ethnographic field experience in Zimbabwean mainstream newsrooms. The article specifically focuses on the practicalities of deploying ethnography to study the fluid and diffuse processes of ICT use in the ‘real-world’ of journalism practice with the high ethnographic standard of firsthand experience. It closely examines how these challenges shaped and constrained the author’s fieldwork and attempts to highlight the strategies employed to manage them. In doing so, the article shows that there is more to gain from ones’ ‘insider-status’ and sustained intuitive and creative inclinations when researching in politically charged and unpredictable contexts such as Zimbabwean newsrooms. The discussion thus offers insight for practically negotiating methodological dilemmas likely to be faced by researchers who may find themselves in similar circumstances.
Process evaluation: the new miracle ingredient in public health research?
Authors: Munro Alison , Bloor Michael
Published: December 2010

Good evaluation practice in public health research has become equated with the inclusion of a mixed-methods ‘process evaluation’ alongside an ‘outcome evaluation’ to gather data on how and why interventions are effective or ineffective. While the incorporation of process evaluations in randomized controlled trials is to be welcomed, there is a danger that they are being oversold. The problematic position of process evaluations is illustrated by data from an evaluation of an unsuccessful schools health promotion intervention. The process evaluation data (designed to ‘explain’ the outcome evaluation results) must be collected before the outcome evaluation results are typically available: unanticipated outcomes cannot always be addressed satisfactorily from prior process data. Further, qualitative process data draw inductively general inferences from particular circumstances and the generalizability of those inferences is therefore uncertain: qualitative data can deepen our understanding of quantitative data, but the commensurability of the two classes of data remains problematic.
Interviews as encounters: issues of sexuality and reflexivity when men interview men about commercial same sex relations
Authors: Walby Kevin
Published: December 2010

Few qualitative sociologists have considered how men who have sex with men hold diverse understandings of sexuality and how these matter in research encounters, especially as it regards ‘touchy’ interview topics such as intimacy, intercourse and men’s bodies. Drawing from transcripts and field notes concerning my experiences of interviewing 30 male-for-male internet escorts in Montréal, Ottawa, Toronto (Canada), Houston and New York (USA), as well as London (England), I analyse moments where, as the interviewer, I was sexualized by respondents. A first question was often posed to me at the start of interviews: ‘ are you gay?’ The ‘ are you gay?’ question not only seeks out a singular identity declaration but also flips over established researcher-respondent roles, indicating that the reflexivity of the respondent is as important as the reflexivity of the researcher in shaping the conversation to come. My analysis demonstrates why it is important to consider the impact of researcher bodies and speech acts during interviews. Arguing that there are specificities of talk and gesture concerning queer sexualities that researchers must be aware of during interviews, I focus on how my responses to respondent propositions and sexualization shaped and modified the meanings produced through the research encounter.
Online petitions: new tools of secondary analysis?
Authors: Briassoulis Helen
Published: December 2010

Since the 1990s, internet-mediated research has been gradually gaining ground in the Social Sciences due, in part, to the expanding use of the internet by public and private organizations and individuals for numerous purposes. Among them, online petitions are often used nowadays to garner support on an issue. In several cases, they generate interesting sets of quantitative and qualitative data that can be used to address apposite research questions related to the cause of the petition and beyond. This research note negotiates selected issues of research methodology and offers examples based on this author’s experience with analysing petition data. The low cost of the wealth of information provided partly compensates for the limitations of online petitions, which more probably will be combined with other methods of scientific research. The role of researchers remains crucial. Thorough knowledge of the broader and specialist literature and familiarity with the theme of the petition are instrumental in making the best and most valid use of petition data.
Apples and oranges: ethnography and the IRB
Authors: Librett Mitch , Perrone Dina
Published: December 2010

This article outlines the trials and tribulations encountered in negotiating institutional review board approval of ethnographic research among undercover police officers and recreational drug users in dance club settings. While Institutional Review Boards (IRBs) and ethnographic research seek to protect the participants of research, they operate on two diametrically opposed paths. Ethnographers enter the research field with the goal of observing natural behavior, and taking steps to ensure they do not influence activity; anonymity is impossible, while confidentiality essential. IRBs, on the contrary, mandate an informed consent and oversight process that can compromise confidentiality. This has greatly affected contemporary ethnographic research and has had serious consequences for both the research participants and the production of knowledge.
Effects of Massage Therapy on African Americans with Type 2 Diabetes Mellitus: A Pilot Study
Authors: Edwards B.G. , Palmer J.
Published: December 2010

Aims: African American (AA) subjects with type 2 diabetes mellitus were studied to determine effects of Massage Therapy/Acupressure (MTA) on vital signs (VS): blood pressure (BP), heart rate (HR), blood flow (BF), skin temperature (TEMP), O2 saturation (O2); well-being (WB); glycosylated hemoglobin (A1c), cortisol, and insulin. Method: Eleven AA ages 45 to 72, (8 female/3 males) were subjects. VS were obtained before and after each of 20, 60-minute MTA sessions. BF was measured with a Pulsed Doppler and decibel meter. Blood collections (n = 9) and Well-Being-22 Questionnaires [(WBQ-22) n = 11] were completed at baseline and following the 20th massage. MTA involved acupressure on spine-T-8/T-9, Urinary Bladder-UB17/UB23/U2, Stomach-ST2, Kidney-K5, Renal-R3; and Effleurage-gliding/stroking, Petrissage-kneading, Tapotement-cupping/hacking/pinching of extremities, and back/torso and Vibration Friction-neck. Hand pressure provided massage to the pancreas. VS were analyzed with General Estimation Equations, and Wilcoxon Sign Tests evaluated WBQ-22/blood work. Results: Pre/Post MTA BF increased with sessions (p = .001). Immediately following a MTA session, BP (systolic) increased while HR and TEMP decreased. Over-time MTA therapy led to significant increases in HR and BF, while TEMP decreased. No significant changes in cortisol, A1c, or insulin were noted. WBQ-22 parameters improved insignificantly; +Energy, +Positive WB, and +Total WB. Anxiety/Depression decrease. 19.5%/13.8%, respectively. Conclusions: Immediate effects of MTA were increased BP (systolic) and lower HR and TEMP. Long-term effects were higher resting HR and increased BF, while TEMP significantly decreased. MTA was feasible, well received and could have potential health benefits. Randomized controlled studies are needed to thoroughly explore this therapy as a useful adjunct to conventional allopathic care.
The Peace Support Operations Model: Origins, Development, Philosophy and Use
Authors: Body Howard , Marston Colin
Published: December 2010

This article is intended to give the reader of this special Journal of Defense Modeling and Simulation edition an introduction to the UK Ministry of Defence’s Peace Support Operations Model (PSOM). It provides first a general description of the rationale and structure of the model, explaining something of the design philosophy and how this was translated into a viable game/model approach. The origins and need for a simple Irregular Warfare (IW) tool are explained and the expanding stakeholder interest catalogued. Issues of doctrine and terminology provided a constant challenge to the Study, and the PSOM’s efforts to navigate around these, and the friction from residual kinetic modelling legacy, is addressed. The progression from prototype to the current working model is described, along with the PSOM’s current development plans and approach. The intention to enhance the model’s representation of a number of ‘soft’ effects is stressed; some of these are introduced here and expanded in other papers included in this edition. Finally, a description of the extensive international collaboration and configuration control, particularly with the US, leaves the reader understanding that the PSOM provides a potentially unifying IW modelling approach to nations engaged in complex operations.
How I treat: the selection and acquisition of unrelated cord blood grafts
Authors: Barker Juliet N. , Byam Courtney , Scaradavou Andromachi
Published: December 2010

Use of unrelated donor cord blood (CB) as an alternative stem cell source is increasing, and yet there is little information to guide transplant centers in the unique aspects of the search and selection of CB grafts. There is no mechanism to easily access the global inventory of CB units, nor is the product information provided by all banks standardized. To address these challenges, this manuscript reviews the logistics of the search, selection process, and acquisition of CB grafts as practiced by our center. Topics include who should be considered for a CB search, how to access the global CB inventory, and how to balance total nucleated cell dose and human leukocyte antigen match in unit selection. We discuss aspects of unit quality and other graft characteristics (processing methods, unit age, availability of attached segments, infectious disease, and hemoglobinopathy screening) to be considered. We incorporate these considerations into a unit selection algorithm, including how to select double-unit grafts. We also describe how we plan for unit shipment and the role of backup grafts. This review aims to provide a framework for CB unit selection and help transplantation centers perform efficient CB searches.
A frequency-approximated approach to Kirchhoff migration
Authors: Vardy Mark E. , Henstock Timothy J.
Published: December 2010

The integral solution of the wave equation has long been one of the most popular methods for imaging (Kirchhoff migration) and inverting (Kirchhoff inversion) seismic data. For efficiency, this process is commonly formulated as a time-domain operation on each trace, applying antialiasing through high-cut filtering of the operator or pre-/postmigration dip filtering. Migration in the time domain, however, does not allow for velocity dispersion; standard antialiasing methods assume a flat reflector and tend to overfilter the data. We have recast the Kirchhoff integral in the frequency domain, enabling robust antialias filtering through appropriate dip limiting of each frequency and implicit accommodation of true dispersion. Full frequency decomposition of the input seismogram can be approximated by band-pass filtering (or correlation with band-limited source sweeps for Chirp/Vibroseisdata) into a few narrow-band traces that cumulatively retain the full source bandwidth. From prior knowledge of the source waveform, we have defined suitable bandwidths to describe broadband (3.0 octaves) data using just six frequency bands. Kirchhoff migration of these narrow-band traces using coefficients determined at their central frequencies significantly improves the preservation of higher frequencies and cancellation of steeply dipping aliased energy over traditional time-domain antialiasing methods. If, however, two bands per octave cease to be a robust approach, our frequency-approximated approach provides the processor with ultimate control over the frequency decimation, balancing increased resolution afforded by more bands against computing cost, whereas the number of frequency bands is few enough to permit detailed control over frequency-dependent antialias filtering parameters.
Applications of multiscale waveform inversion to marine data using a flooding technique and dynamic early-arrival windows
Authors: Boonyasiriwat Chaiwoot , Schuster Gerard T. , Valasek Paul , Cao Weiping
Published: December 2010

A recently developed time-domain multiscale waveform tomography (MWT) method is applied to synthetic and field marine data. Although the MWT method was already applied to synthetic data, the synthetic data application leads to a development of a hybrid method between waveform tomography and the salt flooding technique commonly use in subsalt imaging. This hybrid method can overcome a convergence problem encountered by inversion with a traveltime velocity tomogram and successfully provides an accurate and highly resolved velocity tomogram for the 2D SEG/EAGE salt model. In the application of MWT to the field data, the inversion process is carried out using a multiscale method with a dynamic early-arrival muting window to mitigate the local minima problem of waveform tomography and elastic effects. With the modified MWT method, reasonably accurate results as verified by comparison of migration images and common image gathers were obtained. The hybrid method with the salt flooding technique is not used in this field data example because there is no salt in the subsurface according to our interpretation. However, we believe it is applicable to field data applications.
INTRODUCTION
Authors: Love Heather
Published: December 2010

This introduction for “Rethinking Sex” frames the contributions of Gayle Rubin to the contemporary field of sexuality studies through a discussion of her 1984 essay “Thinking Sex.” It discusses the 2009 conference that was the basis for this special issue as well as the significance of Rubin's career and her scholarship, focusing in particular on links between feminism and queer studies, empiricism and description, coalitional politics, and memory and the significance of archives.
Mechanisms of mechanical signaling in development and disease
Authors: Janmey Paul A. , Miller R. Tyler
Published: December 2010

The responses of cells to chemical signals are relatively well characterized and understood. Cells also respond to mechanical signals in the form of externally applied force and forces generated by cell–matrix and cell–cell contacts. Many features of cell function that are generally considered to be under the control of chemical stimuli, such as motility, proliferation, differentiation and survival, can also be altered by changes in the stiffness of the substrate to which the cells are adhered, even when their chemical environment remains unchanged. Many examples from clinical and whole animal studies have shown that changes in tissue stiffness are related to specific disease characteristics and that efforts to restore normal tissue mechanics have the potential to reverse or prevent cell dysfunction and disease. How cells detect stiffness is largely unknown, but the cellular structures that measure stiffness and the general principles by which they work are beginning to be revealed. This Commentary highlights selected recent reports of mechanical signaling during disease development, discusses open questions regarding the physical mechanisms by which cells sense stiffness, and examines the relationship between studies in vitro on flat substrates and the more complex three-dimensional setting in vivo.
A population-based survey of Asian women's experience of premenstrual symptoms
Authors: Dennerstein Lorraine , Lehert Philippe , Keung Lam Siu , Pal Sadiah Ahsan , Choi Dooseok
Published: December 2010

Objective

This paper aims to explore women's experiences of premenstrual symptoms in three Asian countries and the factors affecting the prevalence of these symptoms.

Study design

Cross-sectional survey. A sample of 1202 women aged 15–49 years were recruited by random sampling in Hong Kong, Pakistan and Thailand.

Main outcome measures

The interviewer used a questionnaire with a checklist of 23 premenstrual symptoms, sociodemographic and lifestyle variables.

Results

The most prevalent symptoms were joint, muscle and back pain, cramps, abdominal pain and breast tenderness. The severity of symptoms was directly proportional to duration (months affected) ( R = 0.85). Significant effects on symptom duration, severity, index of age (linear and quadratic effects), educational level and parity were found by multiple regression. There were also differences between countries for certain symptoms.

Conclusions

Physical symptoms are an important component of premenstrual syndromes. These have been shown to be psychobiological in nature. Further analysis will examine the impact on the quality of life and the relationship with existing classificatory systems.
Imperfect Competition in Financial Markets: An Empirical Study of Island and Nasdaq
Authors: Biais Bruno , Bisière Christophe , Spatt Chester
Published: December 2010

The competition between Island and Nasdaq at the beginning of the century offers a natural laboratory to study competition between and within trading platforms and its consequences for liquidity supply. Our empirical strategy takes advantage of the difference between the pricing grids used on Island and Nasdaq, as well as of the decline in the Nasdaq tick. Using the finer grid prevailing on their market, Island limit order traders undercut Nasdaq quotes, much more than they undercut one another. The drop in the Nasdaq tick size triggered a drop in Island spreads, despite the Island tick already being very thin before Nasdaq decimalization. We also estimate a structural model of liquidity supply and find that Island limit order traders earned rents before Nasdaq decimalization. Our results suggest that perfect competition cannot be taken for granted, even on transparent open limit order books with a very thin pricing grid.
The Behavior of Risk and Market Prices of Risk Over the Nasdaq Bubble Period
Authors: Bakshi Gurdip , Wu Liuren
Published: December 2010

We exploit the information in the options market to study the variations of return risk and market prices of different sources of risk during the rise and fall of the Nasdaq market. We specify a model that accommodates fluctuations in both risk levels and market prices of different sources of risk, and we estimate the model using the time-series returns and option prices on the Nasdaq 100 tracking stock. Our analysis reveals three key variations during the period from March 1999 to March 2001. First, return volatility increased together with the rising Nasdaq index level, even though the two tend to move in opposite directions. Second, although the market price of diffusion return risk averages around 1.82 over the whole sample, the estimates reached negative territory at the end of 1999. The estimates reverted back to highly positive values after the collapse of the Nasdaq market. Third, the market price of jump risk increased with the rising Nasdaq valuation, and this increase in market price coincided with an increased imbalance in open interest between put and call options.
A Dynamic Inventory Model with the Right of Refusal
Authors: Bhaskaran Sreekumar , Ramachandran Karthik , Semple John
Published: December 2010

We consider a dynamic inventory (production) model with general convex order (production) costs and excess demand that can be accepted or refused by the firm. Excess demand that is accepted is backlogged and results in a backlog cost whereas demand that is refused results in a lost sales charge. Endogenizing the sales decision is appropriate in the presence of general convex order costs so that the firm is not forced to backlog a unit whose subsequent satisfaction would reduce total profits. In each period, the firm must determine the optimal order and sales strategy. We show that the optimal policy is characterized by an optimal buy-up-to level that increases with the initial inventory level and an order quantity that decreases with the initial inventory level. More importantly, we show the optimal sales strategy is characterized by a critical threshold, a backlog limit, that dictates when to stop selling. This threshold is independent of the initial inventory level and the amount purchased. We investigate various properties of this new policy. As demand stochastically increases, the amount purchased increases but the amount backlogged decreases, reflecting a shift in the way excess demand is managed. We develop two regularity conditions, one that ensures some backlogs are allowed in each period, and another that ensures the amount backlogged is nondecreasing in the length of the planning horizon. We illustrate the buy-up-to levels in our model are bounded above by buy-up-to levels from the pure lost sales and pure backlogging models. We explore additional extensions using numerical experiments.
Optimal Bundling of Technological Products with Network Externality
Authors: Prasad Ashutosh , Venkatesh R. , Mahajan Vijay
Published: December 2010

For many high-tech and Internet-related products, utility to consumers depends in part on the size of the user base, a phenomenon called network externality. A firm with a portfolio of these and other products—that are often asymmetric in their degree of network externality or marginal cost—may have to look beyond the traditional strategies of pure components, pure bundling, and mixed bundling. One such strategic alternative in a two-product case would be a so-called mixed bundling-1 under which the bundle and product 1 are offered, but the other product can only be purchased in a bundled form. The purpose of this study is to compare and contrast the impact of such asymmetry or symmetry in (direct) network externality and cost on the choice of bundling strategies. We model a monopolist firm that has a product in each of two categories and faces heterogeneous consumers. Results suggest that pure bundling is more profitable when both products have low marginal costs or high network externality whereas pure components or mixed bundling-1 is more profitable when the products diverge in their costs and network externality (e.g., only one product has network externality). Traditional mixed bundling is optimal in other instances.
Preparation and Characterization of Magnetic Composites Based on a Natural Zeolite
Authors: Gutiérrez Marlen , Escudey Mauricio , Escrig Juan , Denardin Juliano C. , Altbir Dora , Fabris Jose D. , Cavalcante Luis C. D. , García-González María Teresa
Published: December 2010

A magnetic composite was prepared by wet-impregnating a powder of a natural zeolite with a magnetic Fe oxide-containing synthetic material. Both starting materials were first characterized with X-ray diffraction, scanning electron microscopy, Mössbauer spectroscopy, and by isoelectric-point using vibrating-sample magnetometry. The synthetic Fe oxide-containing material was characterized as a mixture of magnetite (Fe3O4) and goethite (α-FeOOH). From the Fe Mössbauer analysis, the relative subspectral area for magnetite corresponds to 93(2)%; the remaining spectrum is assignable to goethite. After the impregnation process, magnetite was still identified in the composite material as a magnetic layer surrounding the zeolite particles; no magnetically ordered goethite could be detected. The Mössbauer pattern for this sample indicates a much more complex structure than for the precursor material, based on Fe oxides, with some more altered magnetite and an intense central doublet of (super)paramagnetic Fe3+, probably due to small Fe (hydr)oxides and/or to a residual contribution of Fe-bearing species from the starting zeolite material. The composite preparation procedure also promoted the change of the characteristic A-type zeolite to mordenite. The resulting magnetic composite presented a magnetic coercivity of as much as 0.140 A m−1, at 77 K. The final composite is now being evaluated as an adsorbent: results to date confirm that this novel magnetic material may have applications in the remediation of contaminated water bodies.
Synthesis and Characterization of Zn-Al Layered Double Hydroxides Intercalated With 1- to 19-Carbon Carboxylic Acid Anions
Authors: Kuehn Thomas , Poellmann Herbert
Published: December 2010

Layered double hydroxides (LDHs) are layered ion exchangers, with a large surface-charge density, which react easily with organic anions. Various types of organics are rapidly substituted in the interlayer space of inorganic precursor LDHs. ZnAl-LDHs were intercalated with 1- to 19-carbon monocarboxylic acid anions by anion exchange of NO3-saturated LDH precursor phases in order to study the dependence of exchange reactions on synthesis parameters (temperature, pH, and interlayer anion). The carboxylic acid anion-LDHs synthesized were characterized using X-ray diffraction, infrared spectroscopy, thermal analysis, scanning electron microscopy, chemical analysis, and N2 adsorption. Carboxylic anion quantities in excess of the LDH anion exchange capacity easily replaced exchangeable nitrate anions at moderate pH. The intercalated LDH interlayer space depended on the alkyl chain length and orientation (inclination angle) of thecarboxylic-acid anion. Thelatticeparameter c0 ranged from 3.4 to 13.5 nm, but the a0 lattice parameter remained constant at 0.31 nm. Crystallographic analyses indicated a monomolecular arrangement of intercalated short-chain fatty-acid anions. At pH < 7, intercalated long-chain carboxylates showed a preferred bimolecular interlayer orientation. Carboxylic-acid anion exchange with LDHs at pH 7 resulted in the formation of two different sets of basal spacings, which indicated the coexistence of LDHs intercalated with monomolecular and bimolecular arrangements of interlayer carboxylic compounds.

Thermal treatment of the carboxylic acid anion-intercalated LDHs indicated stability up to ~140ºC. The release of interlayer water led to distortion of the crystallographic units and resulted in smaller basal spacings without collapse of the layered structure. Heat treatment re-oriented alkyl-chain carbon carboxylates (with >10 carbons) to a more upright interlayer position.
Saponite-Rich Black Shales and Nontronite Beds of the Permian Irati Formation: Sediment Sources and Thermal Metamorphism (Paraná Basin, Brazil)
Authors: Dias Dos Anjos Camila Wense , Meunier Alain , Guimarães Edi Mendes , El Albani Abderrazzak
Published: December 2010

Shales and claystones in the Permian Irati Formation consist of Al-rich or Fe-Mg clay minerals in its southern/central and northern parts, respectively. The constrasting compositions indicate particular geological and paleo-environmental conditions. The purpose of this study was to determine the conditions of formation by characterizing the black shales and claystones from different sections of the northern edge of the basin, some of which reveal the presence of intruded diabase sills.

Black shales consist of saponite or saponite-talc mixed layers, talc, lizardite, nontronite, and quartz. Green claystones are nontronite-rich but also contain lizardite, talc, and quartz. The chemical compositions of the black shale and claystones, except for one sample (POR-56), exhibit a positive correlation of the TiO2, Cr, and P2O5 contents with Al2O3, which typically results from weathering processes. The presence of saponite, nontronite, and some accessory minerals (spinel, pyroxene, native silver) suggests altered basic-ultrabasic rocks as sediment sources, consistent with the rare earth element (REE) composition being less than the Post-Archean Average Shale (PAAS) or North American Shale Composite (NASC) levels and with negative Ce and Eu anomalies. Sample POR-56 consists largely of nontronite and is anomalously rich in zircon, monazite, and apatite. Chemically, sample POR-56 is different from the black shales and claystones, being richer in Al2O3-Fe2O3, MgO-poor, and having greater REE contents than the PAAS or NASC standards. The POR-56 bed is probably a bentonite resulting from the alteration of volcanic ash in sea water (strong, negative Ce anomaly). The Zr/TiO2vs. Nb/Y relation indicates that the magmatism was andesitic. During the Upper Permian, intermediate to basic volcanic activity was recorded in the Mitu Group of the Central Andes.

Close to the diabase sill, the black shales and claystones contain saponite, talc, and lizardite but nontronite is absent. Saponite and talc crystals, however, exhibit a larger coherent scattering domain size (CSDS) and are randomly oriented with respect to the sedimentary bedding. The thermal metamorphism effect is confirmed by the presence of secondary enstatite-augite and albite crystals.
Element Distribution Between Coexisting Authigenic Mineral Phases in Argillic and Zeolitic Altered Tephra, Olduvai Gorge, Tanzania
Authors: McHenry Lindsay J.
Published: December 2010

The current study demonstrates how co-existing zeolite and clay minerals formed by the alteration of tephra in a closed-basin lacustrine and lake-margin environment can retain the overall composition of the original bulk tephra for many elements, even when diagenetic conditions and resulting authigenic mineral assemblages change. Zeolite and clay minerals co-exist in the closed-basin, saline-alkaline lacustrine altered tephra of Pleistocene Olduvai Gorge, Tanzania, and their diagenetic histories can be reconstructed using variations in their textures and compositions. The authigenic minerals in the altered tephra of the Olduvai paleolake form a classic ‘bull’s-eye’ pattern, with clay-dominated tephra in the distal lake margin, chabazite and phillipsite in the proximal margin, and phillipsite ± K-feldspar in the intermittently dry lake and lake center. Fifteen representative samples of altered volcanic ash lapilli (designated Tuff IF) were analyzed by X-ray diffraction (XRD), X-ray fluorescence (XRF), electron probe microanalysis (EPMA), and scanning electron microscopy (SEM) to determine their authigenic mineral assemblages and bulk compositions, and to texturally and compositionally compare their clay mineral and zeolite components.

Textural observations indicate that clay minerals formed first, followed by zeolites and finally feldspars. Clay minerals, however, persist even in the most altered samples. The overall composition of Tuff IF shows only limited change in Fe, Si, Al, and Na between fresh, clay-altered, and zeolite-dominated diagenetic environments, despite significant differences in authigenic assemblage. Where zeolites dominate the assemblage, the remaining clay minerals are rich in Mg, Fe, and Ti, elements that are not readily incorporated in zeolite structures. Where clay minerals dominate, they are more Al-rich. A ‘mixing model’ combining clay-mineral and zeolite compositions yields a close approximation of the original volcanic glass for most elements (exceptions including Mg, Ca, and K). This initial composition was preserved in part by the redistribution of elements between co-existing clay minerals and zeolites.
Common Variations in the Genes Encoding C-Reactive Protein, Tumor Necrosis Factor-α, and Interleukin-6, and the Risk of Clinical Diabetes in the Women's Health Initiative Observational Study
Authors: Chan Kei-hang K , Brennan Kathleen , You Nai-chieh Y , Lu Xuyang , Song Yiqing , Hsu Yi-Hsiang , Chaudhuri Gautum , Nathan Lauren , Tinker Lesley , Liu Simin
Published: December 2010

BACKGROUND

Circulating concentrations of high-sensitivity C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) have been associated with an increased risk of diabetes.

METHODS

To examine the roles of genetic variation in the genes encoding CRP, TNF- α, and IL-6 in the development of diabetes, we conducted a prospective case–control study nested within the Women's Health Initiative Observational Study. We followed 82 069 postmenopausal women (50–79 years of age) with no history of diabetes for incident diabetes for a mean follow-up of 5.5 years. We identified 1584 cases and matched them with 2198 controls with respect to age, ethnicity, clinical center, time of blood draw, and length of follow-up. We genotyped 13 haplotype-tagging single-nucleotide polymorphisms (tSNPs) across 2.3 kb of the CRP (C-reactive protein, pentraxin-related) gene, 16 tSNPs across 2.8 kb of the TNF (tumor necrosis factor) gene, and 14 tSNPs across 4.8 kb of the IL6 [interleukin 6 (interferon, beta 2)] gene. Plasma concentrations of TNF-α receptor 2 (TNF-α-R2) and IL-6 were measured.

RESULTS

After adjusting for matching factors, confounding variables, and multiple comparisons, we found 8 variants in the TNF gene to be associated with plasma TNF-α-R2 concentrations in white women (q < 0.05). After adjusting for multiple comparisons (q > 0.05), we found no association of any IL6 gene variant with plasma IL-6 concentration, nor did we find any significant associations between any SNPs among these 3 genes and diabetes risk (q > 0.05).

CONCLUSIONS

We found modest associations between TNF variants and circulating concentrations of TNF-α-R2. Common variants of the CRP, TNF, and IL6 genes were not significantly associated with risk of clinical diabetes in postmenopausal women.
Two Dads: Gay Male Parenting and its Politicisation — A Cooperative Inquiry Action Research Study
Authors: Tuazon‐McCheyne Jason
Published: December 2010

Australian gay men have only recently become parents through surrogacy arrangements. They have had to overcome a discriminatory legal, social, political, cultural and financial environment. A cooperative inquiry action research group was formed, with seven two‐father families conceived via surrogacy, to explore their journey to parenthood and their consequent politicisation as gay fathers. This article reveals how that experience of the cooperative inquiry process strengthened their resolve to be intentionally ‘out’ in their communities to overcome discriminatory and conservative social attitudes. They embraced the political reality of their parenting and were stimulated to create improved support structures for themselves and future parents. This transformed the legal, social, political and cultural environment for their families.
‘Coming Out Tales’: Adult Sons and Daughters' Feelings About Their Gay Father's Sexual Identity
Authors: Tasker Fiona , Barrett Helen , De Simone Federica
Published: December 2010

Coming out to their children is a dilemma that concerns many gay, bisexual, and lesbian parents with children from previous heterosexual relationships. How children found out about having a father who identified himself as gay, and their feelings about their father's sexual identity, were explored through qualitative analysis of semi‐structured interviews with 36 sons and daughters (aged 19 to 36 years) whose gay fathers participated in the Gay & Bisexual Parenting Survey (Barrett and Tasker, 2001). Interpretative Phenomenological Analysis revealed that awareness of their father's sexual identity was often left unspoken for various reasons, and that acceptance came about through gradual understanding as well as direct discussion. Interview data indicated the complexity of the relationship between the young adult's personal acceptance of their father's gay identity and their consideration of social context when deciding how open to be to others about their father's sexual identity. This research has varied implications for therapeutic work with gay and bisexual fathers coming out to their children from previous heterosexual relationships.
Planned Gay Father Families in Kinship Arrangements
Authors: Bos Henny H.M.W.
Published: December 2010

The current study examined whether there are differences between gay father families (n = 36) and heterosexual families (n = 36) on father‐child relationship, fathers' experiences of parental stress and children's wellbeing. The gay fathers in this study all became parents while in same‐sex relationships. They donated sperm to lesbian couples and then shared the child‐rearing with them in kinship arrangements. It was also examined whether aspects that are related specifically to gay fathers (i.e., experiences of rejection, having to defend their family situation, with whom the children live, and conflicts with the children's mothers) are also related to the father‐child relationship, parental stress and children's wellbeing. Data were collected by means of questionnaires filled in by the fathers. No significant differences between the family types were found on emotional involvement and parental concern in the father‐child relationship, parental burden (as an aspect of parental stress) or the children's wellbeing. However, gay fathers felt less competent in their child‐rearing role than heterosexual fathers. For gay fathers especially, experiences of rejection and the feeling that they have to defend their situation were significantly related to father‐child relationship, parental stress and children's wellbeing.
A Commentary on ‘Common SNPs Explain a Large Proportion of the Heritability for Human Height’ by Yang et al. (2010)
Authors: Visscher Peter M. , Yang Jian , Goddard Michael E.
Published: December 2010

Recently a paper authored by ourselves and a number of co-authors about the proportion of phenotypic variation in height that is explained by common SNPs was published inNature Genetics(Yang et al., 2010). Common SNPs explain a large proportion of the heritability for human height (Yang et al.). During the refereeing process (the paper was rejected by two other journals before publication inNature Genetics) and following the publication of Yang et al. (2010) it became clear to us that the methodology we applied, the interpretation of the results and the consequences of the findings on the genetic architecture of human height and that for other traits such as complex disease are not well understood or appreciated. Here we explain some of these issues in a style that is different from the primary publication, that is, in the form of a number of comments and questions and answers. We also report a number of additional results that show that the estimates of additive genetic variation are not driven by population structure.
The Serotonin Transporter Gene Length Polymorphism (5-HTTLPR) and Life Events: No Evidence for an Interaction Effect on Neuroticism and Anxious Depressive Symptoms
Authors: Middeldorp Christel M. , de Geus Eco J. C. , Willemsen Gonneke , Hottenga Jouke-Jan , Slagboom P. Eline , Boomsma Dorret I.
Published: December 2010

The finding of a significant gene by environment interaction effect on depression of the serotonin transporter length polymorphism (5-HTTLPR) and the Number of experienced Life Events (NLE) was not replicated in two large meta-analyses (Munafo et al., 2009; Risch et al., 2009). These meta-analyses have been criticized on the grounds that large studies that get most weight in meta-analyses have the poorest measurement quality of life events and, as a consequence, do not find an effect. Another issue is the time frame across which the NLE are measured. Proximal life events appear to be better predictors of depression than more distal events. We present the results of analyses of the 5-HTTLPR × NLE effect on anxious depression and neuroticism scores in a sample of 1,155 twins and their parents and siblings from 438 families. The interaction effect was tested separately for NLE experienced across the life span and NLE experienced in the past year. There was a significant main effect of NLE on anxious depression and neuroticism, especially when these were experienced in the past year. No interaction with 5-HTTLPR was found for NLE either experienced across the life span or across the past year. Our results support the two recent meta-analyses. Given recent insights from genome wide association studies, it seems more useful to focus on the joint effect of several genes, that are, for example, part of the same biological pathway, in interaction with the environment, than on one candidate gene.
Externalizing Behaviors and Cigarette Smoking as Predictors for Use of Illicit Drugs: A Longitudinal Study Among Finnish Adolescent Twins
Authors: Korhonen Tellervo , Levälahti Esko , Dick Danielle M. , Pulkkinen Lea , Rose Richard J. , Kaprio Jaakko , Huizink Anja C.
Published: December 2010

We examined whether externalizing problem behaviors (hyperactivity–impulsivity, aggressiveness, and inattention) predict illicit drug use independently, or whether their associations with drug use are mediated through cigarette smoking. We used a prospective longitudinal design within theFinnTwin12-17study among Finnish adolescents with baseline at age 12 and follow-up surveys at ages 14 and 17. Path models were conducted withMplusand included 1992 boys and 2123 girls. The outcome was self-reported ever use of cannabis or other illicit drugs at age 17. The predictors were: externalizing behaviors (hyperactivity–impulsivity, aggressiveness, and inattention) assessed by teachers and parents (age 12) and self-reported cigarette smoking (age 14). The findings differed across behavior studied. The association of hyperactivity–impulsivity with drug use was mostly mediated through earlier cigarette smoking. Concerning aggressiveness and inattention, the results were different among girls than boys. Among girls no significant mediation occurred, whereas among boys more consistent evidence on mediation was seen. Consistently in all models, the direct association of early cigarette smoking on drug use was strong and highly significant. We conclude that the associations of externalizing problem behaviors with illicit drug use are partially mediated through cigarette smoking. Although interventions targeting externalizing problem behaviors may protect adolescents from early onset smoking and subsequently experimenting with drugs, interventions to prevent cigarette smoking initiation are also important in reducing risk of later drug use.
Genetic Modeling of Primary Tooth Emergence: A Study of Australian Twins
Authors: Bockmann Michelle R. , Hughes Toby E. , Townsend Grant C.
Published: December 2010

The aim of this study was to quantify contributions of genetic and environmental factors to variation in timing of emergence of the primary teeth in a sample of monozygotic and dizygotic twins, using univariate model-fitting approaches. The sample comprised 94 pairs of monozygotic twins and 125 pairs of dizygous twins, all of European ancestry, aged from 2–6 years. Tooth emergence timing was based on parental report, with a subset of data validated by clinical assessment. Heritability estimates for tooth emergence timing were generally high, around 90%, however estimates for the lower right lateral incisor and the lower canines were around 50%. These findings confirm a strong genetic influence on observed variation in the timing of emergence of the human primary teeth.
Outcome of Twin Pregnancies Complicated By Early Second Trimester Rupture of Membranes in One Sac
Authors: Zajicek Michal , Yagel Simcha , Ben-Ami Moshe , Weisz Boaz , Keselman Leandro , Lipitz Shlomo
Published: December 2010

The aim of this study was to present the outcome of bichorionic twin pregnancies complicated by early second trimester rupture of membranes in one sac. Data regarding all cases of ruptured membranes at 13–20 weeks in bichorionic twin pregnancies were collected retrospectively from three fetal medicine units. Patients who have chosen to terminate the pregnancy were excluded from the study. Between January 2003 and July 2009, nine patients met inclusion criteria. Three out of nine couples decided on expectant management, and six preferred selective feticide. With expectant management one fetus died in utero and take home baby rate was 83% (5 of 6 fetuses), delivered at 27–32 weeks. When selective termination was performed, all non-reduced fetuses were born alive at 33–40 weeks. Two survivors of rupture of membranes had limb contractures, none had lung hypoplasia. One patient had clinical signs of amnionitis, which was ruled out later on pathological examination. Her post partum course was uncomplicated. Our data suggest that rupture of membranes in one sac of bichorionic twins at 13–20 weeks has favorable prognosis whether an intervention is preformed or not. Nonetheless, selective termination may have an advantage over expectant management, since gestational age at delivery was higher when selective termination was performed.
The Frequency and Clinical Significance of Twin Gestations According to Zygosity and Chorionicity
Authors: Lee Kyung A. , Oh Kyung Joon , Lee Seung Mi , Kim Ahm , Jun Jong Kwan
Published: December 2010

Background:Although the clinical importance of chorionicity in twin pregnancies has been studied widely, the significance of perinatal determination of zygosity using molecular genetic analyses remains controversial. The purpose of this study was to determine the frequency and clinical significance of twin gestations according to zygosity and chorionicity in a Korean population.Methods:We enrolled 569 women who delivered twin newborns (> 24 weeks) at Seoul National University Hospital between 1999 and 2008. Chorionicity was established by histologic examination of placentae. Zygosity was determined with sex of neonates, chorionicity, and DNA analysis of umbilical cord blood.Results:The frequency of dizygotic (DZ) twins was 71.0% (404/569 pairs) based on the opposite sex (238/404 [58.9%]) and DNA analyses (166/404 [41.1%]); that of monozygotic (MZ) twins was 29.0% (165/569), including monochorionic (MC) (72.1% [119/165]) and dichorionic (DC) twins (27.9% [46/165]), which was confirmed by DNA analyses. Among spontaneously conceived twins, the frequency of MZ twins was more than twice that of DZ twins. The risk of low birth weight was 1.8-fold higher among MZDC twins and 1.9-fold higher among MZMC twins than among DZDC twins (p< .05). Bronchopulmonary dysplasia occurred more frequently among MZMC twins than among DZDC twins (adjusted OR 8.42, 95% CI 1.82–39.08,p< .01). However, the frequencies of other neonatal morbidities were not significantly higher in the MZMC group than in the MZDC and DZDC groups. The perinatal mortality rate was 15 per 1000 total births in the DZDC twins, 20 per 1000 total births in the MZDC and 56 per 1000 total births in the MZMC (p< .01).Conclusions:Although monozygosity was shown to be a risk factor for perinatal death and accurate determination of zygosity plays a great role in the future consideration of organ transplantation and twin studies, the value of zygosity determination along with chorionicity in relation to overall neonatal morbidity was not definite.