bluuebunny/crossref_metadata_2025 huggingface dataset:
Mental health of the non-heterosexual population of
England
Authors: Chakraborty Apu , McManus Sally , Brugha Terry S. , Bebbington Paul , King Michael
Published: January 2011

Background

There has been little research into the prevalence of mental health
problems in lesbian, gay and bisexual (LGB) people in the UK with most
work conducted in the USA.

Aims

To relate the prevalence of mental disorder, self-harm and suicide
attempts to sexual orientation in England, and to test whether
psychiatric problems were associated with discrimination on grounds of
sexuality.

Method

The Adult Psychiatric Morbidity Survey 2007 (n = 7403)
was representative of the population living in private UK households.
Standardised questions provided demographic information. Neurotic
symptoms, common mental disorders, probable psychosis, suicidality,
alcohol and drug dependence and service utilisation were assessed. In
addition, detailed information was obtained about aspects of sexual
identity and perceived discrimination on these grounds.

Results

Self-reported identification as non-heterosexual (determined by both
orientation and sexual partnership, separately) was associated with
unhappiness, neurotic disorders overall, depressive episodes, generalised
anxiety disorder, obsessive–compulsive disorder, phobic disorder,
probable psychosis, suicidal thoughts and acts, self-harm and alcohol and
drug dependence. Mental health-related general practitioner consultations
and community care service use over the previous year were also elevated.
In the non-heterosexual group, discrimination on the grounds of sexual
orientation predicted certain neurotic disorder outcomes, even after
adjustment for potentially confounding demographic variables.

Conclusions

This study corroborates international findings that people of
non-heterosexual orientation report elevated levels of mental health
problems and service usage, and it lends further support to the
suggestion that perceived discrimination may act as a social stressor in
the genesis of mental health problems in this population.
Coming home may hurt: risk factors for mental ill health in US
reservists after deployment in Iraq
Authors: Riviere Lyndon A. , Kendall-Robbins Athena , McGurk Dennis , Castro Carl A. , Hoge Charles W.
Published: January 2011

Background

Little research has been conducted on the factors that may explain the
higher rates of mental health problems in United States National Guard
soldiers who have deployed to the Iraq War.

Aims

To examine whether financial hardship, job loss, employer support and the
effect of deployment absence on co-workers were associated with
depression and post-traumatic stress disorder (PTSD).

Method

Cross-sectional data were obtained from 4034 National Guard soldiers at
two time points. All measures were assessed by self-report.

Results

The four factors were associated with depression and PTSD, with
variability based on outcome and time point. For example, job loss
increased the odds of meeting criteria for depression at 3 and 12 months
and for PTSD at 12 months; the negative effect of deployment absence on
co-workers increased the likelihood of meeting criteria for PTSD, but not
depression, at both time points.

Conclusions

The findings demonstrate that National Guard soldiers have unique
post-deployment social and material concerns that impair their mental
health.
Violence against mental health staff: a survey in a Nigerian psychiatric hospital
Authors: Ukpong Dominic Ignatius , Owoeye Olugbenga , Udofia Owoidoho , Abasiubong Festus , Ukpong Sunday
Published: January 2011

Aims and method

A survey was conducted to investigate physical assaults against mental health staff of a Nigerian psychiatric hospital in a 12-month period and also during their working career in the hospital retrospectively using a questionnaire method.

Results

In total, 101 out of 120 questionnaires were completed (response rate 84.2%). Within the period of their employment in the hospital 49.5% of staff had been physically assaulted at least once, and over the previous 12 months 33.7% had been physically assaulted. Nursing staff (82.3%) were more frequently assaulted than doctors, most often during routine assessment of patients (44.3%). In total, 88% of staff sustained injuries requiring medical attention. Vulnerability to assaults was not associated with attending a course on prevention and management of psychiatric patient violence.

Clinical implications

Assaults by patients against mental health staff, especially nurses, are quite widespread in Nigeria. There is a need to formulate policies on prevention and management of violence in people with mental disorders in Nigerian psychiatric hospitals.
THE CHIMERA OF RELATIVISM
Authors: Smith Barbara Herrnstein
Published: January 2011

In this contribution to the Common Knowledge symposium “Comparative Relativisim,” Smith argues that relativism is a chimera, half straw man, half red herring. Over the past century, she shows, objections to the supposed position so named have typically involved either crucially improper paraphrases of general observations of the variability and contingency of human perceptions, interpretations, and judgments or dismaying inferences gratuitously drawn from such observations. More recently, the label relativism has been elicited by the display, especially by anthropologists or historians, of attitudes of epistemic tolerance or efforts at explanatory or evaluative symmetry. Objections here commonly involve mistaken, unwarranted universalizing of those attitudes or recommendations. Purported refutations of what is identified as relativism commonly have no force for alleged relativists because relativism-refuters commonly deploy and depend on the very concepts (e.g., truth and reason) and relations (e.g., between what are referred to as facts and evidence) that are at issue. The result is circular argumentation, intellectual nonengagement, and perfect deadlock. Although there are signs that this tragicomic episode of intellectual history has run its course, two contemporary sites of antirelativist energy are worth noting. One is the claim that so-called cultural relativism is refuted by the existence of cognitive universals. The other is the fear that evaluative symmetry leads to ethically or politically debilitating neutrality. Consideration of the nature of cognitive universals indicates that their existence does not contradict observations of the significance of cultural variability. Consideration of anxieties about the supposed quietistic implications of commitments to epistemic tolerance or symmetry indicates that such anxieties are misplaced.
COMPARISON AS A MATTER OF CONCERN
Authors: Stengers Isabelle
Published: January 2011

The question of universalism and relativism is often taken to be a matter of critical reflexivity. This article attempts to present the question instead as a matter of practical, political, and always-situated concern. The attempt starts from the consideration of modern experimental sciences. These sciences usually serve as the stronghold for universalist claims and as such are a target of relativism. It is argued that the specificity of these sciences is not a method but a concern. To be able to claim that they have not unilaterally imposed their definitions on the phenomena they study is the leading concern of experimenters and should be understood in terms of the following achievement: the creation of a very particular “rapport” that authorizes claiming that what is operationally defined “lends itself” to this correlation. Linking knowledge production with a creation of rapports entails a pluralization of sciences along with the pluralization of modes of concern associated with the rapport. However, resisting unilaterally imposed definitions is not enough, since with the coming “knowledge economy” the questions that this article raises will soon be part of a romantic past. Thus it concludes with a speculative touch, which may be a requiem, relating the creation of rapports with an ecology of practices akin to William James's always-under-construction pluriverse.
COMPARISON AS PARTICIPANT
Authors: Verran Helen
Published: January 2011

This comment argues that Isabelle Stengers, in her article “Comparison as a Matter of Concern,” is justifiably concerned about the future of science in an imperium of commerce where epistemology has no clout. Agreeing with Stengers that we should focus attention on comparison-as-participant, this comment relates Stengers's argument to Verran's own work in contexts where the epistemic practices of science are challenged—in science lessons in Nigeria (case 1) and in episodes where environmental scientists try to work with Aboriginal Australian landowners (case 2). Drawing inspiration from her African and Aboriginal colleagues, Verran disagrees with Stengers that the only option for science is to make the terms of its defeat explicit. This comment suggests that the sciences might learn from other knowledge traditions in finding the places and the means to develop divergent practices through which resistance is possible. Verran identifies temporal disjunctions as possible sites of innovation, suggesting that contemporary sciences should forego their backward-looking traditional epistemic practices and learn to focus instead on equipping their participant-comparisons for an uncertain future.
RATS, ELEPHANTS, AND BEES AS MATTERS OF CONCERN
Authors: Brown Steven D.
Published: January 2011

This commentary on Isabelle Stengers's article, “Comparison as a Matter of Concern” is an assessment of her stance toward experimental psychology. At the various points in her work where she considers that discipline, she tends to accuse it of failing to embrace the “risk” that she sees as defining the “collective games” of science. Brown invokes the behavioral approach to experimental psychology of the early to mid-twentieth century to contextualize Stengers's treatment of continuous comparison conducted by scientists around “matters of concern.” Her use of the metaphor of predator/prey relationships between practices is seen as reversing the usual direction of critique within psychology, such that experimental psychology appears to have, in the Wistar rat, an object grounding a community that is capable of performing continuous comparison, which its critics contrastingly lack. Stengers's ecological view of practices may then ultimately lead to a reappraisal of branches of the human sciences, such as experimental psychology, which she tends, on occasion, to dismiss.
HOPEFUL COMPARISONS ON THE BRINK OF THE GRAVE
Authors: Winthereik Brit Ross
Published: January 2011

This commentary on Isabelle Stengers's article “Comparison as a Matter of Concern,” takes its entry point in a battle between comparisons: imposed comparisons, where extraneous, irrelevant criteria are laid down, and active, interested comparisons, where rapport is established between the scientist and the phenomenon she studies. According to Stengers, the comparison, which establishes rapport, is a crucial ingredient in good science. In the context of a symposium titled “Comparative Relativism,” perhaps the crucial point to make about what characterizes Stengers's matter of concern is that, in being utterly uninterested in defining absolute scales for comparison and in focusing only on the generative potential of comparing, she relativizes the very act of comparing. What matters to her is how experimental devices simultaneously sensitize their users to the phenomena at hand and to the workings of particular comparisons. Since (a relativized) comparison is a matter of concern to the scientists involved, finding out what other ways of comparing there are (besides objectivist comparison) should be a matter of concern to those of us who are engaged in studying knowledge production. This commentary suggests that “knowledge economy” researchers begin unpacking the science/industry collaboration through participation and careful analysis as a way of staying with the present moment.
SCIENCES WERE NEVER “GOOD”
Authors: Stengers Isabelle
Published: January 2011

This piece is an answer to the responses of Helen Verran, Steven D. Brown, and Brit Ross Winthereik to the author's article, “Comparison as a Matter of Concern.” She acknowledges the difficulty of her respondents to accept her claim that the sciences may be destroyed as many practices before them have been. She opposes, however, an “adaptationist” or “transformationist” perspective, in order to emphasize that, if the sciences are to survive, a radical mutation would be needed. She emphasizes that what is at stake is not a “good science” threatened by its alliance with industry. The recruitment of powerful allies has been part of the scientific enterprise since its beginning. What is at stake is the collective fabric of sciences as characterized by Bruno Latour in terms of “links and knots.”
BINARY LICENSE
Authors: Strathern Marilyn
Published: January 2011

This article exploits the “binary license” offered by the title of the symposium in which it appears (“Comparative Relativism”) as a kind of promise of connection. The author suggests, however tentatively, that in the challenge of heterogeneity, fractality, perspective/-alism, and multiplicities lies the power of the forking pathway: the moment a relation is created through divergence. If we are invited—in the same breath—to consider forms of comparison and forms of relativism (dropping difference and similarity), we are also offered two paths, one based on a world of singularities and multiplicities, and the other on a world of not-quite repetitions. The article asks if the binary is not essential to the epistemic work that Western (Euro-American) scholars might want to do, since we forever reinvent the divide between the modern and the post-/pre-modern. Strathern assumes the anthropologist's license to talk about concepts through persons, and begins by asking how Papua New Guineans who come together in a city compare themselves, and in contrast to ethnic comparisons elsewhere (e.g., contra Sarah Green's Balkan interactions). In talking about persons through concepts, it is worth asking what is entailed in relativizing one scholar's work through that of another. The author says that her “hunch” is that in both cases the analyst might wish to have the liberty of discerning—in the same breath—the multiplicities of what John Law and Annemarie Mol call perspectivalism (their very general alternative to comparison) and Eduardo Viveiros de Castro's radically divergent perspectivism (a self-contained, recursive and above all socially specific relativism).
STRATHERN'S NEW COMPARATIVE ANTHROPOLOGY
Authors: Kapferer Bruce
Published: January 2011

This piece addresses Marilyn Strathern's article, “Binary License,” and the important contribution she makes to the development of an anthropology that is truly comparative and that aims to escape some important disadvantages of an earlier relativism. This comment places her in the context of the related effort of Louis Dumont, which involved a sustained critique of Eurocentricism, in which he saw anthropological comparativism as hitherto being bound. A question is raised concerning the extent to which Strathern has escaped the kind of criticism that Dumont developed. Additionally, Strathern's Hagen materials are considered in relation to the earlier Zambian studies of the “Manchester school” of anthropology and which addressed similar ethnographic materials. Strathern's work is regarded in this comment as bearing some similarity with current directions in actor-network theory, although sustaining an ontological approach that is seen by some as contributing to the risks of anthropological relativism. The comment attempts to work within the spirit of Strathern's original contribution and is concerned with how anthropological comparativism may avoid some of the pitfalls that are commonly associated with it.
ONE, TWO, THREE
Authors: Mol Annemarie
Published: January 2011

This piece is a response to Marilyn Strathern's article, “Binary License,” in the Common Knowledge symposium on “comparative relativism.” Arguing that, across noncoherent practices, there is room for different natures, the essay suggests that modes of relating (the briefly invoked example given is of divergent counting practices) do not need a shared conceptual apparatus in order to be combined. What is held in the juxtaposition of acts and practices seems to be the sense in which acts are not affected by how they are described. The main example given is of surgery, and the emphasis placed on how splitting open part of patient's body is never a matter of a point of view. But to know exactly what is going on in the operating theater, we might wish to ask how this act speaks to the act of intellectual bifurcation, splitting open what up to then had been a seamless argument. To know exactly what is going on in the operating theater, we might also wish to ask how this act speaks to persons cutting themselves off from one another.
NON-IDENTITY POLITICS
Authors: Pedersen Morten Axel
Published: January 2011

This commentary on Marilyn Strathern's article, “Binary License,” discusses certain implications of her assertion that intertribal relationships among urban migrants in Papua New Guinea are not “ethnic.” For if such social encounters do not involve a conventional politics of identity, what then might its politics be? By comparing Strathern's Melanesian case with ethnographic examples in Corsica and Mongolia, a novel relational modality of “intensive ethnicity” may be identified, one that differs qualitatively from the “extensive ethnicity” with which anthropologists have usually been concerned. The two forms of ethnicity are equally relative, in that a given group's self-understanding and self-designation are in both cases the result of its relations with other groups. However, ethnically extensive relations of the standard anthropological variety involve symbolic processes of boundary making and boundary maintenance whereby contrasting cultural traits or contents are arbitrarily assigned to and distributed among preexisting social forms and social scales (whether individuals, communities, or nations). Conversely, the more intensive intertribal engagements described by Strathern and certain other anthropologists are relational all the way down, given that everything about the terms of these relations (including their form, scale, and dimensioning) is defined by the particular quality in question. Thus a contrast may be established between the politics of identity and what might be called non-identity politics. If the former amounts to an ethnic economy in which subjectivities are exchanged in a commodity-like, alienable way, then, in the latter, stereotypical naming and other seeming “ethnic” practices amount to gift-like, non-alienable insertions of selves into others.
ZENO AND THE ART OF ANTHROPOLOGY
Authors: de Castro Eduardo Viveiros
Published: January 2011

The article assumes that the expression “comparative relativism”—the title of the Common Knowledge symposium in which the essay appears—is neither tautological nor oxymoronic. Rather, the author construes the term as an apt synthetic characterization of anthropology and illustrates that idea by means of four quotations, taken from authors as different as Richard Rorty and David Schneider, Marcel Mauss and Henri Michaux. The quotations can be said to “exemplify” anthropology in terms that are interestingly (and diversely) restrictive: some of them amount to extrinsic negations of anthropology that would paralyze it; others suggest intrinsic negativities that would propel it. All of the passages chosen evoke the idea of belief, which is profoundly implicated, in all possible senses (and especially the worse ones), in the majority of arguments that connect the themes of anthropology, comparison, and relativism.
VÚJÀ DE AND THE QUINTESSENTIALISTS' GUILD
Authors: Wagner Roy
Published: January 2011

This essay asks: Is “culture” the subject of a communication among anthropologists, or are anthropologists subjects to a communication among cultures? Put more simply, is there only one culture, comprised of multiplex variations recovered from various parts of an ever-changing world, or are there a great many, all of them variations on a single theoretical insight, which anthropologists have made up in secret and carefully keep as a secret from themselves? (Why not? the author asks, adding that such is exactly how the modern state operates.) Is it possible, he further asks, for a memory to have an independent existence, untroubled by the people who constantly keep occurring to it? It is of course absurd to ascribe agency to what amount to mere figures of speech, metaphors, or enigmatic perceptual cues, “but if a metaphor could not think, as an agency in and of itself, then neither could we.” (Memories would have to be metaphors; otherwise how could we forget them?) Finally, the essays asks: What is more natural than the agency of the one you see in the mirror, that steals your act of looking, but only to view itself?
Isoaspartate-dependent molecular switches for integrin–ligand recognition
Authors: Corti Angelo , Curnis Flavio
Published: January 2011

Integrins are cell-adhesion receptors that mediate cell–extracellular-matrix (ECM) and cell–cell interactions by recognizing specific ligands. Recent studies have shown that the formation of isoaspartyl residues (isoAsp) in integrin ligands by asparagine deamidation or aspartate isomerization could represent a mechanism for the regulation of integrin–ligand recognition. This spontaneous post-translational modification, which might occur in aged proteins of the ECM, changes the length of the peptide bond and, in the case of asparagine, also of the charge. Although these changes typically have negative effects on protein function, recent studies suggested that isoAsp formation at certain Asn-Gly-Arg (NGR) sites in ECM proteins have a gain-of-function effect, because the resulting isoAsp-Gly-Arg (isoDGR) sequence can mimic Arg-Gly-Asp (RGD), a well-known integrin-binding motif. Substantial experimental evidence suggests that the NGR-to-isoDGR transition can occur in vitro in natural proteins and in drugs containing this motif, thereby promoting integrin recognition and cell adhesion. In this Commentary, we review these studies and discuss the potential effects that isoAsp formation at NGR, DGR and RGD sites might have in the recognition of integrins by natural ligands and by drugs that contain these motifs, as well as their potential biological and pharmacological implications.
The Cabals of a Few or the Confusion of a Multitude: The Institutional Trade-off Between Representation and Governance
Authors: Brooks Leah , Phillips Justin , Sinitsyn Maxim
Published: January 2011

Our model illustrates how political institutions trade off between the competing goals of representation and governance, where governance is the responsiveness of an institution to a single pivotal voter. We use exogenous variation from the 30-year history of the federal Community Development Block Grant program to identify this trade-off. Cities with more representative governments—those with larger city councils—use more grant funds to supplement city revenues rather than implementing tax cuts, thereby moving policy further away from the governance ideal. In sum, more representative government is not without cost. (JEL D72, H71, R50)
Payment Choice, Image Motivation and Contributions to Charity: Evidence from a Field Experiment
Authors: Soetevent Adriaan R
Published: January 2011

This paper examines the impact of payment choice on charitable giving with a door-to-door fund-raising field experiment. Respondents can donate cash only, use debit only, or have both options. Cash donations have lower visibility vis-à-vis solicitors than debit card donations. When debit replaces cash, participation drops by 87 percent. Conditional on participation, donors in the Debit-only treatment give more than donors in Cash-only. In Cash&Debit, almost all donors prefer cash; participation decreases compared to Cash-only. Physical attractiveness of both female and male solicitors increases contributions. Solicitor self-confidence has a negative impact. (JEL D14, D64, L31)
The Effect of Classmate Characteristics on Post-Secondary Outcomes: Evidence from the Add Health
Authors: Bifulco Robert , Fletcher Jason M , Ross Stephen L
Published: January 2011

This paper uses a within-school/across-cohort design to present new evidence of the effects of high school classmate characteristics on a wide range of post-secondary outcomes. We find that increases in the percent of classmates with college-educated mothers decreases the likelihood of dropping out and increases the likelihood of attending college, despite showing no impact on a range of in-school achievement, attitudes, and behaviors. The percent of students from disadvantaged minority groups does not show any effects on post-secondary outcomes, but is associated with students reporting less caring student-teacher relationships and increased prevalence of some undesirable student behaviors during high school. (JEL I21, J13, J15)
Transfer Program Complexity and the Take-Up of Social Benefits
Authors: Kleven Henrik Jacobsen , Kopczuk Wojciech
Published: January 2011

We model complexity in social programs as a by-product of the screening process. While a more rigorous screening process may improve targeting efficiency, the associated complexity is costly to applicants and induces incomplete take-up. We integrate the study of take-up with the study of rejection (Type I) and award (Type II) errors, and characterize optimal programs when policy makers choose screening intensity (and complexity), an eligibility rule, and a benefit level. Consistent with many real-world programs, optimal programs feature high complexity, incomplete take-up, classification errors of both Type I and II and, in some cases, “excessive” benefits. (JEL D04, D82, H23, I18, I38)
Calorie Posting in Chain Restaurants
Authors: Bollinger Bryan , Leslie Phillip , Sorensen Alan
Published: January 2011

We study the impact of mandatory calorie posting on consumers' purchase decisions using detailed data from Starbucks. We find that average calories per transaction fall by 6 percent. The effect is almost entirely related to changes in consumers' food choices—there is almost no change in purchases of beverage calories. There is no impact on Starbucks profit on average, and for the subset of stores located close to their competitor Dunkin Donuts, the effect of calorie posting is actually to increase Starbucks revenue. Survey evidence and analysis of commuters suggests the mechanism for the effect is a combination of learning and salience. (JEL D12, D18, D83, L83)
Medical Students Compete for College Prize
Authors: Chinn Naomi
Published: January 2011

On 3 November 2010 the 15 other finalists and I made our way to the Royal College of Surgeons for the final stage of the Professor Harold Ellis Medical Student Prize for Surgery 2010. Each candidate had reached this stage after submitting a 500-word abstract on the assigned title:'Which surgical specialty will become extinct first and why?' The first round had been entered by around 60 hopefuls so every finalist had done well to get through to the final stage.
John Hunter's Beard
Authors: Livesley Brian
Published: January 2011

In this paper, evidence is provided to show that the John Hunter portrait owned by the Worshipful Society of Apothecaries (WSA) was painted by Sir Joshua Reynolds as a preliminary sketch for his famous portrait donated to the College by Mrs Hunter and her son. The provenance of the sketch has been disputed by art experts, who have given no explanation about how Hunter came to have the beard that features in the WSA portrait. The answer is a simple clinical one.
Medical Museums Past, Present and Future
Authors: Alberti Sam
Published: January 2011

It is tempting, especially for those working in them, to think that the turbulence experienced by medical museums in the past two decades has been unprecedented. However, these fascinating collections have always been subject to change: in ownership, in purpose, in audience. Museums are not static mausolea but are dynamic, vibrant entities that grow, shrink and adapt to shifting circumstances. As our own Hunterian Museum approaches the bicentenary of its opening here in Lincoln's Inn Fields, it seems a good time to reflect on the key historical shifts, to assess where medical museums are now and to suggest where they might go next.
Shortening length of stay in breast cancer surgery
Authors: Marsden Jo
Published: January 2011

The Cancer Reform Strategy is currently undergoing a review and improving access to short stay surgery is top of the agenda. This move will start making its presence felt in hospitals around the country. The Bulletin asked one surgeon who has successfully applied this in her own department to offer some pointers for getting on top of the process.
Children from Developing Nations Requiring Specialist Surgery
Authors: Boys A , Hutchison I , Murugiah M
Published: January 2011

We love surgery because through it we can improve or even save lives, often instantaneously. Excision of cancer can prevent death, shattering of stones can silence pain, repairing a cleft completes a smile and replacing a valve rejuvenates a life. A skilled surgeon holds the power to transform.
Operation Orange
Authors: Casey Heather
Published: January 2011

A wave of laughter ripples around the table when it becomes clear that the consultant surgeon in the group is struggling to remove the 'nipple' of his orange with his pink craft knife. Before long Kelly Stevens, workshop host and patient of Sheikh Ahmad, interrupts saying: 'the next step will be to scoop out the flesh of our oranges, if Sheikh gets a move on.' Sheikh holds his hands up in response:'Give me a break; I've been awake for 32 hours straight!'
Europe moves
Authors: Black John
Published: January 2011

It is now two years since the College began its campaign against the restrictions of the European Working Time Regulations (EWTR). In February 2009 I asked Alan Johnson, the Secretary of State for Health, for an opt-out for all the surgical specialties up to a maximum 65-hour week of work and on-call, a figure defined as optimum by our two trainee organisations (the Association of Surgeons in Training (ASiT) and the British Orthopaedic Trainees Association (BOTA)). My request was declined and in theory if not in practice all junior doctors in the NHS have worked a 48-hour week since August 2009. It is a matter of regret that all the adverse effects we predicted have come about.
Automated Fitting of X-Ray Powder Diffraction Patterns from Interstratified Phyllosilicates
Authors: Yuan Hongji , Bish David L.
Published: January 2011

NEWMOD®, developed by R.C. Reynolds, Jr., has been an important tool for evaluating quantitatively X-ray diffraction (XRD) patterns from interstratified clay minerals for more than 20 years. However, a significant drawback to the NEWMOD® approach is that analyses are done by forward simulation, making results sensitive to user input and starting-model assumptions. In the present study, a reverse-fitting procedure was implemented in a new program, FITMOD, which automatically minimizes the differences between experimental and simulated XRD patterns. The differences are minimized by varying model parameters (such as Reichweite, crystal-size distribution, cation content, type of disorder, etc.) using the downhill simplex method. The downhill simplex method is a non-linear optimization technique for determining minima of functions. This method does not require calculation of the derivatives of the functions being minimized, an important consideration with many of the parameters in NEWMOD- type simulations. Instead, the downhill simplex method calculates pseudo-derivatives by evaluating sufficient points to define a derivative for each independent variable. The performance of FITMOD was evaluated by fitting a series of synthetic XRD patterns generated by NEWMOD+, yielding agreement factors, Rwp, of <0.3%. As long as the correct interstratified system was specified (e.g. illite-smectite), excellent fits were obtained irrespective of the starting parameters for the simulations. FITMOD was also tested using experimental XRD patterns, which gave very good fits, in agreement with previously published results. The optimization routine yields good fits for both synthetic and experimental XRD profiles in a reasonable time, with the possibility of varying all important structural parameters. FITMOD automatically provides optimum fits to experimental XRD data without operator bias, and fitting efficiency and accuracy were, therefore, significantly improved.
Evolution of Boron and Nitrogen Content During Illitization of Bentonites
Authors: Środoń Jan
Published: January 2011

The incorporation of boron (B) and nitrogen (N) into illite is the key demand-side process responsible for the diagenetic budget of these elements in sedimentary basins, with important implications for pore-water chemistry, natural-gas composition, and borehole geophysics. The purpose of the present study was to take advantage of recent advances in quantitative mineral analysis of sedimentary rocks which have opened new possibilities for investigating this particular process. In order to avoid complications with recycled (detrital) N and B, clays from pyroclastic horizons of sedimentary rocks (bentonites) were used. The B and N contents in illite-smectite were measured in samples from different sedimentary basins, representing a complete range of diagenetic alteration. The bulk-rock chemical measurements, performed on raw rock samples in order to avoid any loss of exchangeable B and N, were referred to the contents of illite-smectite clays and to the content of illite alone, both measured by a combination of XRD and chemistry-based techniques.

Both B and N (as NH4) are present in illite, so their contents in illite-smectite clay increase in a more or less linear manner with progressing illitization. Thus, during diagenesis, the illite-smectite clay is a net consumer of B and N from the pore water. The amount of N in individual illite layers decreases during diagenesis and the amount of B either decreases or remains stable. Bentonitic illite must acquire both B and N from outside of the bentonite bed. In one diagenetic cycle, bentonitic illite fixes up to 800–1000 ppm B and up to >1% N expressed as (NH4)2O, corresponding to >20% of the fixed cation sites.
Illitization of Kaolinite: The Effect of Pressure on the Reaction Rate
Authors: Mantovani Marco , Becerro Ana Isabel
Published: January 2011

Studies of the paragenesis of authigenic illite in arkosic sandstones of various regions and ages have revealed that the illitization of kaolinite is an important reaction accounting for the formation of authigenic illite in sandstones during burial diagenesis. The illitization of kaolinite takes place at an intermediate burial depth of 3–4 km, where pressure can reach values of 100 MPa (≈ 1000 bars). The purpose of the present study was to analyze the effect of pressure on the rate of kaolinite illitization in alkaline conditions. Hydrothermal reactions were conducted on KGa-1b kaolinite in KOH solution at 300°C and under pressures of 500, 1000, and 3000 bars for 1 to 24 h. The visual examination of the X-ray diffraction (XRD) patterns indicated a notable influence of pressure on the reaction rate. Molar percentages of muscovite/illite formed at each time interval were calculated from the analysis of two diagnostic XRD peaks, representing the 060 reflections of kaolinite and muscovite/illite. The data were modeled to obtain the initial rate of conversion at each pressure. The results indicated that the initial rate of kaolinite to muscovite/illite conversion is one order of magnitude greater at 3000 bars than at 500 or 1000 bars. Comparison of these data with those in the literature show a faster conversion rate (several orders of magnitude) in an initially high-alkaline solution than in a near-neutral solution.
XAS Study of Fe Mineralogy in a Chronosequence of Soil Clays Formed in Basaltic Cinders
Authors: Baker Leslie L. , Strawn Daniel G. , Vaughan Karen L. , McDaniel Paul A.
Published: January 2011

The characterization of poorly crystalline minerals formed by weathering is difficult using conventional techniques. The objective of this study was to use cutting-edge spectroscopic techniques to characterize secondary Fe mineralogy in young soils formed in basaltic cinders in a cool, arid environment. The mineralogy of a chronosequence of soils formed on 2, 6, and 15 thousand year old basaltic cinders at Craters of the Moon National Monument (COM) was examined using synchrotron-based X-ray absorption fine structure (XAFS) spectroscopy in combination with selective extractions. Fe K-edge XAFS is useful for determining speciation in poorly crystalline materials such as young weathering products. Over 86% of Fe in the soil clay fractions was contained in poorly crystalline materials, mostly in the form of ferrihydrite, with the remainder in a poorly crystalline Fe-bearing smectite. The XAFS spectra suggest that ferrihydrite in the 15 ka soil clay is more resistant to ammonium oxalate (AOD) extraction than is ferrihydrite in the younger materials. Fe in the poorly crystalline smectite is subject to dissolution during citrate-bicarbonate- dithionite (CBD) extraction. The results indicate that relatively few mineralogical changes occur in these soils within the millennial time frame and under the environmental conditions associated with this study. Although the secondary mineral suite remains similar in the soils of different ages, ferrihydrite crystallinity appears to increase with increasing soil age.
Characterization of Organo-Bentonites Obtained from Different Linear-Chain Quaternary Alkylammmonium Salts
Authors: Erkan Ïlker , Alp Ïbrahim , Çelik Mehmet SabrÏ
Published: January 2011

The effects of surfactants on bentonites have been of great scientific interest for many years. Even though quaternary alkylammonium salts (QAS) have been studied, very few data are available on the comparative performance of different chain-length QAS for the modification of the surface properties and adsorption properties of bentonites. The objective of this study was to investigate the effect of chain length on the adsorption of cationic surfactants onto bentonite. The surface and adsorption properties of different chain-length QAS, i.e. hexadecyltrimethylammonium bromide (HTAB, C16), tetradecyltrimethylammonium bromide (TTAB, C14), and dodecyltrimethylammonium bromide (DTAB, C12), to produce organo- bentonites (OB) were studied. The concentrations of QAS were selected based on the cation exchange capacity (CEC) of the clay mineral. Zeta potential, swelling, and viscosity measurements and scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) analyses were used to explain the changes in surface properties. The results indicated that the best modification of bentonite was obtained using a 16-carbon chain length QAS (HTAB) in a 1:1 ratio of QAS to CEC. The basal spacing at this concentration was measured to be 22.19 Å, which also corresponded to the maximum adsorption density. The OB produced at this concentration showed the best hydrophobic character based on the swelling tests in toluene. The extent of hydrophobicity and adsorption density was correlated with the CEC and alkyl chain of the QAS. All these properties were used to elucidate the mechanism of modification governing the bentonite/QAS system.
Atomic Force Microscopy Method for Measuring Smectite Coefficients of Friction
Authors: Kosoglu Laura M. , Bickmore Barry R. , Filz George M. , Madden Andrew S.
Published: January 2011

The coefficient of friction of clay minerals at the micro-scale has generally not been studied due to difficulties in obtaining measurements in a bulk-soil volume undergoing shear at such small scales. Information on friction at the micro-scale may provide insight into grain-scale processes that operate in bulk samples or in natural faults. The objective of this study was to develop a method to measure the microscale friction coefficient of smectites. The experiments described show that the axial atomic force microscopy method can be adapted to easily obtain accurate coefficient of friction (μ) measurements for smectites from force curves involving colloidal probes. The method allows for the measurements to be performed over spatial scales of a few μm, can be carried out under dry conditions or a wide range of aqueous solutions, and requires no calibration beyond making a few microscopic measurements of the probe. This method provides measurements of micro-scale normal and shear forces between minerals, which can be used for a variety of applications such as the study of shear deformation, consolidation, and fault dynamics. Control tests of silica on mica (μ = 0.29±0.02) agree with literature values where limits indicate one standard deviation. Coefficient of friction values for wet and dry Na-montmorillonite were determined to be 0.20±0.03 and 0.72±0.03, respectively.
Reductive Degradation ofp,p′-DDT cy Fe(II) in Nontronite NAu-2
Authors: Fialips Claire I. , Cooper Nicola G. A. , Jones D. Martin , White Maggie L. , Gray Neil D.
Published: January 2011

Clay minerals are abundant in soils and sediments and often contain Fe. Some varieties, such as nontronites, contain as much as 40 wt.% Fe2O3within their molecular structure. Several studies have shown that various Fe-reducing micro-organisms can use ferric iron in Fe-bearing clay minerals as their terminal electron acceptor, thereby reducing it to ferrous iron. Laboratory experiments have also demonstrated that chemically or bacterially reduced clays can promote the reductive degradation of various organics, including chlorinated pesticides and nitroaromatics. Therefore, Fe-bearing clays may play a crucial role in the natural attenuation of various redox-sensitive contaminants in soils and sediments. Although the organochlorinated pesticidep,p′-DDT is one of the most abundant and recalcitrant sources of contamination in many parts of the world, the impact of reduced Fe-bearing clays on its degradation has never been documented. The purpose of the present study was to evaluate the extent of degradation ofp,p′-DDT during the bacterial reduction of Fe(III) in an Fe-rich clay. Microcosm experiments were conducted under anaerobic conditions using nontronite (sample NAu-2) spiked with p,p′-DDT and the metal-reducing bacteriaShewanella oneidensisMR-1. Similar experiments were conducted using a sand sample to better ascertain the true impact of the clayvs.the bacteria on the degradation of DDT. Samples were analyzed for DDT and degradation products after 0, 3, and 6 weeks of incubation at 30°C. Results revealed a progressive decrease inp,p′-DDT and increase inp,p′-DDD concentrations in the clay experiments compared to sand and abiotic controls, indicating that Fe-bearing clays may substantially contribute toward the reductive degradation of DDT in soils and sediments. These new findings further demonstrate the impact that clay materials can have on the natural attenuation of pollutants in natural and artificial systems and open new avenues for the passive treatment of contaminated land.
Coupling Among CH Stretching, Bending and Rocking Vibrational Modes in CH2Cl2
Authors: Liua Qing-hua , Li Xiao-ning , Hao Lu-yuan , Tan Chuang , Zhou Yin-gui , Chen Ping , Zhu Huai
Published: January 2011

Infrared absorption spectra of gaseous CH2Cl2 in the regions of 120012000 cm1 were measured using a Bruker IFS 120HR Fourier transform spectrometer in conjunction with a multipass cell. 47 vibrational levels of overtone and combinational spectral lines of the CH stretching (v1, v6), bending (v2), and rocking (v8) modes were analyzed and assigned. Utilizing the normal mode model and considering the coupling among CH stretching, bending and rocking vibrations, values of the harmonic frequency i, the anharmonic constant xij, and the coefficients of Fermi and the Darling-Dennison resonances of v1, v6, v2 and v8 modes were also determined from experimental spectral data with nonlinear least-square fitting. These spectral constants reproduced the experimental levels very well. These results showed that Fermi resonance between CH stretching and rocking vibrations (k188 = 254.63 cm1) is stronger than that between CH stretching and bending vibrations (k122 = 54.87 cm1); and that Darling-Dennison resonances between CH stretching and bending vibrations (k1166 = 215.28 cm1) is also much stronger than that between CH bending and rocking vibrations (k2288 = 5.72 cm1).
Computer Assisted Assignments of Rotationally Resolved Molecular Spectra
Authors: Wu Ling , Zheng Li-juan , Yang Xiao-hua , Liu Yu-yan , Chen Yang-qin
Published: January 2011

A graphically oriented interactive program for assignments of rotationally resolved molecular spectra has been devised. The program functions by grouping spectral lines in term of the second difference principle, and graphing spectral intensity versus frequency in a bar graph of the selected groups, distinguished by color and/or line-type. This allows for easy detection of regular patterns buried in the observed spectrum. Furthermore, it includes a LoomisWood view for assisting in spectral assignments. As an example, the program was applied in assigning the molecular spectrum of the production in the discharge of PCl3 buffered by helium gas, which may belong to several species. The results suggest that the program is highly efficient and quite useful in the assignment and the analysis of molecular spectra, especially those of symmetric top, slightly asymmetric top and linear molecules. The accuracy and efficiency of this program will likely ensure its wide application in the processing of molecular spectra.
Algebraic Study of the Vibrational Levels and Potential Energy Surface of the Excited Electronic State (C1A') for S2O
Authors: Wang Xiao-yan , Ding Shi-liang , Xie Jin-dong , Wang Peng-cheng , Zhong Wei-gang
Published: January 2011

The vibrational levels and potential energy surface of a stable structure for S2O in the excited electronic states C1A' were carried out with algebraic method. The vibrational spectra were obtained (with total quantum number v = 20) by fitting 30 spectra data. The fitted rms (root mean square) error based on the Hamiltonian with 9 parameters was 2.40 cm1. The dissociation energy and force constant were also determined by the analytical potential energy surface. The method is proved to be effective by comparing these results with the experimental data.
Theoretical Comparison of Oxygen Adsorption on Cu(100) Surface
Authors: Chen Wen-kai , Lu Chun-hai , Chen Zhan-hong , Li Yi , Li Jun-qian
Published: January 2011

The interaction of atomic oxygen with the clean Cu(100) surface has been studied by means of cluster and periodic slab models density functional theory in the present paper. The Cu(4,9,4) cluster and a three-layer slab with c(2 2) structure are used to model the perfect Cu(100) surface. Three possible adsorption sites, top, bridge and hollow site, were considered in the calculations. The predicted results show that the hollow site is the prefer site for atomic oxygen adsorbed on Cu(100) surface energetically. This is in good agreement with the experiment. The calculated binding energies are respective 2.014, 3.154 and 3.942 eV for top, bridge and hollow sites at mPW1PW91/LanL2dz level for the cluster model. The geometry of Cu(100) surface has also been optimized theoretically with various density functional methods and the results show that the prediction from the B3PW91/LanL2dz and mPW1PW91/LanL2dz reproduce the experimental observation. The frontier molecular orbitals and partial density of states analysis show that the electron transfer from the d orbital of substrate to the p orbital of the surface oxygen atom.