bluuebunny/crossref_metadata_2025 huggingface dataset:
Excavating Second Life
Authors: Harrison Rodney
Published: February 2009

While the anthropology of online communities has emerged as a significant area of research, there has been little discussion of the possibilities of the archaeology of virtual settlements, defined here as interactive synthetic environments in which users are sensually immersed and which respond to user input. Bartle (in Designing Virtual Worlds, 2003: 1) has described such virtual settlements as `places where the imaginary meets the real'. In this sense, an examination of the role of heritage in virtual settlements has the potential to shed light on the role of heritage in both `real' and `imagined' communities more generally. This article develops the concept of `cyberarchaeology' (originally devised by Jones in his 1997 article, `Virtual Communities') to study the virtual material culture of the settlement Second Life, and in particular, its explicit programme of heritage conservation. A survey of heritage places in Second Life suggests that the functions of heritage in virtual settlements may be far more limited than in the actual world, functioning primarily as a structure of governance and control through the establishment of the rationale for (virtual) land ownership and the production of a sense of community through memorials which produce a sense of `rootedness' and materialize social memory. Such functions of heritage are consistent with recent discussion of the role of heritage in western societies. Nonetheless, this study of heritage and cyber-archaeology provides insights into the ways in which the notions of heritage are transforming in the early 21st century in connection with the proliferation of virtual environments, and the challenge this provides to contemporary society.
The Art of Auto-Mobility
Authors: Chattopadhyay Swati
Published: February 2009

The article examines the images and texts on privately operated public buses in contemporary Calcutta as a form of popular culture. By situating the vehicular art within the larger socio-political milieu of the city, this paper analyzes the manner in which the artwork acts as a unique mode of communication and everyday resistance. A close reading of the relation between the images and texts enables us to grasp the spatial logic by which subaltern groups make room for themselves within the bourgeois frame of the city.
When Cross-Racial Contact Transforms Intercultural Communication Competence
Authors: Kerssen-Griep Jeff , Eifler Karen
Published: February 2009

This study examined whether and why an academic mentoring program affected how skillfully its participants communicated with students from a different cultural environment. Based on theory and research about achieving perspective shift via intercultural contact, this longitudinal study assessed changes in the observed intercultural communication abilities of White preservice teachers over their 8 months as academic mentors for members of an African American cultural group, from whom they themselves learned realities of institutional racism. Analysis revealed several statistically significant improvements in these novice teachers' observed interactional abilities over time. By highlighting actual improved actions, these results extend previous attitude-focused and affect-focused research about intergroup contact outcomes. Advancing antiracism education aims, this report also explicates the teacher training experience that successfully prepared these novice teachers to invest in communicating mindfully and skillfully across cultural boundaries.
Results of high-dose imatinib mesylate in intermediate Sokal risk chronic myeloid leukemia patients in early chronic phase: a phase 2 trial of the GIMEMA CML Working Party
Authors: Castagnetti Fausto , Palandri Francesca , Amabile Marilina , Testoni Nicoletta , Luatti Simona , Soverini Simona , Iacobucci Ilaria , Breccia Massimo , Rege Cambrin Giovanna , Stagno Fabio , Specchia Giorgina , Galieni Piero , Iuliano Franco , Pane Fabrizio , Saglio Giuseppe , Alimena Giuliana , Martinelli Giovanni , Baccarani Michele , Rosti Gianantonio ,   for the GIMEMA CML Working Party
Published: February 2009

Imatinib mesylate has become the treatment of choice for chronic myeloid leukemia (CML): the standard dose for chronic- phase (CP) CML is 400 mg daily. Response rates are different according to Sokal score, being significantly lower in intermediate and high Sokal risk patients. Phase 1 and 2 trials have shown a dose-response effect and high-dose imatinib trials in early CP CML showed better results compared with standard dose. Our study is the first prospective trial planned to evaluate the efficacy and tolerability of high-dose imatinib in previously untreated intermediate Sokal risk CML patients. Seventy-eight patients were treated with 400 mg imatinib twice daily: complete cytogenetic response (CCgR) rates at 12 and 24 months were 88% and 91%; moreover, at 12 and 24 months 56% and 73% of CCgR patients achieved a major molecular response. The incidence of adverse events was slightly higher than reported by the most important standard-dose trials. With a median follow-up of 24 months, 3 patients progressed to advanced phase. In intermediate Sokal risk newly diagnosed CML patients, high-dose imatinib induced rapid and high response rates, apparently faster than those documented in the International Randomized Study of IFN and Imatinib for the same risk category. These clinical trials are registered at www.clinicaltrials.gov as no. NCT00510926.
The F12-Vif derivative Chim3 inhibits HIV-1 replication in CD4+ T lymphocytes and CD34+-derived macrophages by blocking HIV-1 DNA integration
Authors: Porcellini Simona , Alberici Luca , Gubinelli Francesco , Lupo Rossella , Olgiati Clelia , Rizzardi Gian-Paolo , Bovolenta Chiara
Published: February 2009

The viral infectivity factor (Vif) is essential for HIV-1 infectivity and hence is an ideal target for promising anti–HIV-1/AIDS gene therapy. We previously demonstrated that F12-Vif mutant inhibits HIV-1 replication in CD4+ T lymphocytes. Despite macrophage relevance to HIV-1 pathogenesis, most gene therapy studies do not investigate macrophages because of their natural resistance to genetic manipulation. Here, we confirm the F12-Vif antiviral activity also in macrophages differentiated in vitro from transduced CD34+ human stem cells (HSCs). Moreover, we identified the 126- to 170-amino-acid region in the C-terminal half of F12-Vif as responsible for its antiviral function. Indeed, Chim3 protein, containing this 45-amino-acid region embedded in a WT-Vif backbone, is as lethal as F12-Vif against HIV-1. Of major relevance, we demonstrated a dual mechanism of action for Chim3. First, Chim3 functions as a transdominant factor that preserves the antiviral function of the natural restriction factor APOBEC3G (hA3G). Second, Chim3 blocks the early HIV-1 retrotranscript accumulation and thereby HIV-1 DNA integration regardless of the presence of WT-Vif and hA3G. In conclusion, by impairing the early steps of HIV-1 life cycle, Chim3 conceivably endows engineered cells with survival advantage, which is required for the efficient immune reconstitution of patients living with HIV/AIDS.
Healthcare workers' attitudes to working during pandemic influenza: a qualitative study
Authors: Ives Jonathan , Greenfield Sheila , Parry Jayne M , Draper Heather , Gratus Christine , Petts Judith I , Sorell Tom , Wilson Sue
Published: February 2009

Background

Healthcare workers (HCWs) will play a key role in any response to pandemic influenza, and the UK healthcare system's ability to cope during an influenza pandemic will depend, to a large extent, on the number of HCWs who are able and willing to work through the crisis. UK emergency planning will be improved if planners have a better understanding of the reasons UK HCWs may have for their absenteeism, and what might motivate them to work during an influenza pandemic.

This paper reports the results of a qualitative study that explored UK HCWs' views (n = 64) about working during an influenza pandemic, in order to identify factors that might influence their willingness and ability to work and to identify potential sources of any perceived duty on HCWs to work.

Methods

A qualitative study, using focus groups (n = 9) and interviews (n = 5).

Results

HCWs across a range of roles and grades tended to feel motivated by a sense of obligation to work through an influenza pandemic. A number of significant barriers that may prevent them from doing so were also identified. Perceived barriers to the ability to work included being ill oneself, transport difficulties, and childcare responsibilities. Perceived barriers to the willingness to work included: prioritising the wellbeing of family members; a lack of trust in, and goodwill towards, the NHS; a lack of information about the risks and what is expected of them during the crisis; fear of litigation; and the feeling that employers do not take the needs of staff seriously. Barriers to ability and barriers to willingness, however, are difficult to separate out.

Conclusion

Although our participants tended to feel a general obligation to work during an influenza pandemic, there are barriers to working, which, if generalisable, may significantly reduce the NHS workforce during a pandemic. The barriers identified are both barriers to willingness and to ability. This suggests that pandemic planning needs to take into account the possibility that staff may be absent for reasons beyond those currently anticipated in UK planning documents. In particular, staff who are physically able to attend work may nonetheless be unwilling to do so. Although there are some barriers that cannot be mitigated by employers (such as illness, transport infrastructure etc.), there are a number of remedial steps that can be taken to lesson the impact of others (providing accommodation, building reciprocity, provision of information and guidance etc). We suggest that barriers to working lie along an ability/willingness continuum, and that absenteeism may be reduced by taking steps to prevent barriers to willingness becoming perceived barriers to ability.
Chemical tools selectively target components of the PKA system
Authors: Bertinetti Daniela , Schweinsberg Sonja , Hanke Susanne E , Schwede Frank , Bertinetti Oliver , Drewianka Stephan , Genieser Hans-Gottfried , Herberg Friedrich W
Published: February 2009

Background

In the eukaryotic cell the cAMP-dependent protein kinase (PKA) is a key enzyme in signal transduction and represents the main target of the second messenger cAMP. Here we describe the design, synthesis and characterisation of specifically tailored cAMP analogs which can be utilised as a tool for affinity enrichment and purification as well as for proteomics based analyses of cAMP binding proteins.

Results

Two sets of chemical binders were developed based on the phosphorothioate derivatives of cAMP, Sp-cAMPS and Rp-cAMPS acting as cAMP-agonists and -antagonists, respectively. These compounds were tested via direct surface plasmon resonance (SPR) analyses for their binding properties to PKA R-subunits and holoenzyme. Furthermore, these analogs were used in an affinity purification approach to analyse their binding and elution properties for the enrichment and improvement of cAMP binding proteins exemplified by the PKA R-subunits. As determined by SPR, all tested Sp-analogs provide valuable tools for affinity chromatography. However, Sp-8-AEA-cAMPS displayed (i) superior enrichment properties while maintaining low unspecific binding to other proteins in crude cell lysates, (ii) allowing mild elution conditions and (iii) providing the capability to efficiently purify all four isoforms of active PKA R-subunit in milligram quantities within 8 h. In a chemical proteomics approach both sets of binders, Rp- and Sp-cAMPS derivatives, can be employed. Whereas Sp-8-AEA-cAMPS preferentially binds free R-subunit, Rp-AHDAA-cAMPS, displaying antagonist properties, not only binds to the free PKA R-subunits but also to the intact PKA holoenzyme both from recombinant and endogenous sources.

Conclusion

In summary, all tested cAMP analogs were useful for their respective application as an affinity reagent which can enhance purification of cAMP binding proteins. Sp-8-AEA-cAMPS was considered the most efficient analog since Sp-8-AHA-cAMPS and Sp-2-AHA-cAMPS, demonstrated incomplete elution from the matrix, as well as retaining notable amounts of bound protein contaminants. Furthermore it could be demonstrated that an affinity resin based on Rp-8-AHDAA-cAMPS provides a valuable tool for chemical proteomics approaches.
Anti-malarial activities of Andrographis paniculata and Hedyotis corymbosa extracts and their combination with curcumin
Authors: Mishra Kirti , Dash Aditya P , Swain Bijay K , Dey Nrisingha
Published: February 2009

Background

Herbal extracts of Andrographis paniculata (AP) and Hedyotis corymbosa (HC) are known as hepato-protective and fever-reducing drugs since ancient time and they have been used regularly by the people in the south Asian sub-continent. Methanolic extracts of these two plants were tested in vitro on choloroquine sensitive (MRC-pf-20) and resistant (MRC-pf-303) strains of Plasmodium falciparum for their anti-malarial activity.

Methods

Growth inhibition was determined using different concentrations of these plant extracts on synchronized P. falciparum cultures at the ring stage. The interactions between these two plant extracts and individually with curcumin were studied in vitro. The performance of these two herbal extracts in isolation and combination were further evaluated in vivo on Balb/c mice infected with Plasmodium berghei ANKA and their efficacy was compared with that of curcumin. The in vivo toxicity of the plant derived compounds as well as their parasite stage-specificity was studied.

Results

The 50% inhibitory concentration (IC50) of AP (7.2 μg/ml) was found better than HC (10.8 μg/ml). Combination of these two herbal drugs showed substantial enhancement in their anti-malarial activity. Combinatorial effect of each of these with curcumin also revealed anti-malarial effect. Additive interaction between the plant extracts (AP + HC) and their individual synergism with curcumin (AP+CUR, HC+CUR) were evident from this study. Increased in vivo potency was also observed with the combination of plant extracts over the individual extracts and curcumin. Both the plant extracts were found to inhibit the ring stage of the parasite and did not show any in vivo toxicity, whether used in isolation or in combination.

Conclusion

Both these two plant extracts in combination with curcumin could be an effective, alternative source of herbal anti-malarial drugs.
Massively parallel pyrosequencing highlights minority variants in the HIV-1 env quasispecies deriving from lymphomonocyte sub-populations
Authors: Rozera Gabriella , Abbate Isabella , Bruselles Alessandro , Vlassi Crhysoula , D'Offizi Gianpiero , Narciso Pasquale , Chillemi Giovanni , Prosperi Mattia , Ippolito Giuseppe , Capobianchi Maria R
Published: February 2009

Background

Virus-associated cell membrane proteins acquired by HIV-1 during budding may give information on the cellular source of circulating virions. In the present study, by applying immunosorting of the virus and of the cells with antibodies targeting monocyte (CD36) and lymphocyte (CD26) markers, it was possible to directly compare HIV-1 quasispecies archived in circulating monocytes and T lymphocytes with that present in plasma virions originated from the same cell types. Five chronically HIV-1 infected patients who underwent therapy interruption after prolonged HAART were enrolled in the study. The analysis was performed by the powerful technology of ultra-deep pyrosequencing after PCR amplification of part of the env gene, coding for the viral glycoprotein (gp) 120, encompassing the tropism-related V3 loop region. V3 amino acid sequences were used to establish heterogeneity parameters, to build phylogenetic trees and to predict co-receptor usage.

Results

The heterogeneity of proviral and viral genomes derived from monocytes was higher than that of T-lymphocyte origin. Both monocytes and T lymphocytes might contribute to virus rebounding in the circulation after therapy interruptions, but other virus sources might also be involved. In addition, both proviral and circulating viral sequences from monocytes and T lymphocytes were predictive of a predominant R5 coreceptor usage. However, minor variants, segregating from the most frequent quasispecies variants, were present. In particular, in proviral genomes harboured by monocytes, minority variant clusters with a predicted X4 phenotype were found.

Conclusion

This study provided the first direct comparison between the HIV-1 quasispecies archived as provirus in circulating monocytes and T lymphocytes with that of plasma virions replicating in the same cell types. Ultra-deep pyrosequencing generated data with some order of magnitude higher than any previously obtained with conventional approaches. Next generation sequencing allowed the analysis of previously inaccessible aspects of HIV-1 quasispecies, such as co-receptor usage of minority variants present in archived proviral sequences and in actually replicating virions, which may have clinical and therapeutic relevance.
A simple model for the early events of quorum sensing in Pseudomonas aeruginosa: modeling bacterial swarming as the movement of an "activation zone"
Authors: Netotea Sergiu , Bertani Iris , Steindler Laura , Kerényi Ádám , Venturi Vittorio , Pongor Sándor
Published: February 2009

Background

Quorum sensing (QS) is a form of gene regulation based on cell-density that depends on inter-cellular communication. While there are a variety of models for bacterial colony morphology, there is little work linking QS genes to movement in an open system.

Results

The onset of swarming in environmental P. aeruginosa PUPa3 was described with a simplified computational model in which cells in random motion communicate via a diffusible signal (representing N-acyl homoserine lactones, AHL) as well as diffusible, secreted factors (enzymes, biosurfactans, i.e. "public goods") that regulate the intensity of movement and metabolism in a threshold-dependent manner. As a result, an "activation zone" emerges in which nutrients and other public goods are present in sufficient quantities, and swarming is the spontaneous displacement of this high cell-density zone towards nutrients and/or exogenous signals. The model correctly predicts the behaviour of genomic knockout mutants in which the QS genes responsible either for the synthesis (lasI, rhlI) or the sensing (lasR, rhlR) of AHL signals were inactivated. For wild type cells the model predicts sustained colony growth that can however be collapsed by the overconsumption of nutrients.

Conclusion

While in more complex models include self-orienting abilities that allow cells to follow concentration gradients of nutrients and chemotactic agents, in this model, displacement towards nutrients or environmental signals is an emergent property of the community that results from the action of a few, well-defined QS genes and their products. Still the model qualitatively describes the salient properties of QS bacteria, i.e. the density-dependent onset of swarming as well as the response to exogenous signals or cues.

Reviewers

This paper was reviewed by Gáspár Jékely, L. Aravind, Eugene V. Koonin and Artem Novozhilov (nominated by Eugene V. Koonin).
Asymmetric relationships between proteins shape genome evolution
Authors: Notebaart Richard A , Kensche Philip R , Huynen Martijn A , Dutilh Bas E
Published: February 2009

Background

The relationships between proteins are often asymmetric: one protein (A) depends for its function on another protein (B), but the second protein does not depend on the first. In metabolic networks there are multiple pathways that converge into one central pathway. The enzymes in the converging pathways depend on the enzymes in the central pathway, but the enzymes in the latter do not depend on any specific enzyme in the converging pathways. Asymmetric relations are analogous to the “if->then” logical relation where A implies B, but B does not imply A (A->B).

Results

We show that the majority of relationships between enzymes in metabolic flux models of metabolism in Escherichia coli and Saccharomyces cerevisiae are asymmetric. We show furthermore that these asymmetric relationships are reflected in the expression of the genes encoding those enzymes, the effect of gene knockouts and the evolution of genomes. From the asymmetric relative dependency, one would expect that the gene that is relatively independent (B) can occur without the other dependent gene (A), but not the reverse. Indeed, when only one gene of an A->B pair is expressed, is essential, is present in a genome after an evolutionary gain or loss, it tends to be the independent gene (B). This bias is strongest for genes encoding proteins whose asymmetric relationship is evolutionarily conserved.

Conclusions

The asymmetric relations between proteins that arise from the system properties of metabolic networks affect gene expression, the relative effect of gene knockouts and genome evolution in a predictable manner.
PDGF/VEGF signaling controls cell size in Drosophila
Authors: Sims David , Duchek Peter , Baum Buzz
Published: February 2009

Background

In multicellular animals, cell size is controlled by a limited set of conserved intracellular signaling pathways, which when deregulated contribute to tumorigenesis by enabling cells to grow outside their usual niche. To delineate the pathways controlling this process, we screened a genome-scale, image-based Drosophila RNA interference dataset for double-stranded RNAs that reduce the average size of adherent S2R+ cells.

Results

Automated analysis of images from this RNA interference screen identified the receptor tyrosine kinase Pvr, Ras pathway components and several novel genes as regulators of cell size. Significantly, Pvr/Ras signaling also affected the size of other Drosophila cell lines and of larval hemocytes. A detailed genetic analysis of this growth signaling pathway revealed a role for redundant secreted ligands, Pvf2 and Pvf3, in the establishment of an autocrine growth signaling loop. Downstream of Ras1, growth signaling was found to depend on parallel mitogen-activated protein kinase (MAPK) and phospho-inositide-3-kinase (PI3K) signaling modules, as well as the Tor pathway.

Conclusions

This automated genome-wide screen identifies autocrine Pvf/Pvr signaling, upstream of Ras, MAPK and PI3K, as rate-limiting for the growth of immortalized fly cells in culture. Since, Pvf2/3 and Pvr show mutually exclusive in vivo patterns of gene expression, these data suggest that co-expression of this receptor-ligand pair plays a key role in driving cell autonomous growth during the establishment of Drosophila cell lines, as has been suggested to occur during tumor development.
DNA binding-dependent and -independent functions of the Hand2 transcription factor during mouse embryogenesis
Authors: Liu Ning , Barbosa Ana C. , Chapman Shelby L. , Bezprozvannaya Svetlana , Qi Xiaoxia , Richardson James A. , Yanagisawa Hiromi , Olson Eric N.
Published: February 2009

The basic helix-loop-helix (bHLH) transcription factor Hand2 is required for growth and development of the heart, branchial arches and limb buds. To determine whether DNA binding is required for Hand2 to regulate the growth and development of these different embryonic tissues, we generated mutant mice in which the Hand2 locus was modified by a mutation (referred to as Hand2EDE) that abolished the DNA-binding activity of Hand2, leaving the remainder of the protein intact. In contrast to Hand2 null embryos, which display right ventricular hypoplasia and vascular abnormalities, causing severe growth retardation by E9.5 and death by E10.5, early development of the heart appeared remarkably normal in homozygous Hand2EDE mutant embryos. These mutant embryos also lacked the early defects in growth of the branchial arches seen in Hand2null embryos and survived up to 2 to 3 days longer than did Hand2null embryos. However, Hand2EDE mutant embryos exhibited growth defects in the limb buds similar to those of Hand2 null embryos. These findings suggest that Hand2 regulates tissue growth and development in vivo through DNA binding-dependent and -independent mechanisms.
Incentives and Services for College Achievement: Evidence from a Randomized Trial
Authors: Angrist Joshua , Lang Daniel , Oreopoulos Philip
Published: February 2009

This paper reports on an experimental evaluation of strategies designed to improve academic performance among college freshmen. One treatment group was offered academic support services. Another was offered financial incentives for good grades. A third group combined both interventions. Service use was highest for women and for subjects in the combined group. The combined treatment also raised the grades and improved the academic standing of women. These differentials persisted through the end of second year, though incentives were given in the first year only. This suggests study skills among some treated women increased. In contrast, the program had no effect on men. (JEL I21, I28)
The Social Multiplier and Labor Market Participation of Mothers
Authors: Maurin Eric , Moschion Julie
Published: February 2009

In France, as in the US, a mother's labor market participation is influenced by the sex composition of her two eldest siblings. This paper shows that it is also affected by the sex composition of the eldest siblings of the other mothers living in the same close neighborhood. Using the sex composition of neighbors' eldest siblings as an instrumental variable, we identify a significant elasticity of own labor market participation to neighbors' participation. We present supportive evidence by comparing the estimates under two regimes for family benefits (pre- and post-1994 reform) and using quarter of birth as an alternative instrument. (JEL J16, J22)
Sticking with Your Vote: Cognitive Dissonance and Political Attitudes
Authors: Mullainathan Sendhil , Washington Ebonya
Published: February 2009

Cognitive dissonance theory predicts that the act of voting for a candidate leads to a more favorable opinion of the candidate in the future. We find support for the empirical relevance of cognitive dissonance to political attitudes. We examine the presidential opinion ratings of voting-age eligibles and ineligibles two years after the president's election. We find that eligibles show two to three times greater polarization of opinions than comparable ineligibles. We find smaller effects when we compare polarization in opinions of senators elected during high turnout presidential campaign years with senators elected during nonpresidential campaign years. (JEL D72)
Rent Preservation and the Persistence of Underdevelopment
Authors: Rajan Raghuram G
Published: February 2009

When citizens in a poor constrained society are unequally endowed, they are likely to find it hard to agree on reforms, even though the status quo hurts them collectively. Each citizen group or constituency prefers reforms that expand its opportunities, but in an unequal society, this will typically hurt another constituency's rents. Competitive rent preservation ensures no comprehensive reform path may command broad support. The roots of underdevelopment may therefore lie in the natural tendency toward rent preservation in a divided society. (JEL D72, O10, O17)
Convergence in Macroeconomics: Elements of the New Synthesis
Authors: Woodford Michael
Published: February 2009

While macroeconomics is often thought of as a deeply divided field, with less of a shared core and correspondingly less cumulative progress than other areas of economics, in fact, there are fewer fundamental disagreements among macroeconomists now than in past decades. This is due to important progress in resolving seemingly intractable debates. In this paper, I review some of those debates and outline important elements of the new synthesis in macroeconomic theory. I discusses the extent to which the new developments in theory and research methods are already affecting macroeconomic analysis in policy institutions. (JEL A11, E00)
Convergence in Macroeconomics: The Labor Wedge
Authors: Shimer Robert
Published: February 2009

I review research on the behavior of the labor wedge, the ratio between the marginal rate of substitution of consumption for leisure and the marginal product of labor. According to competitive, market-clearing macroeconomic models, the ratio is easy to measure and should be equal to the sum of consumption and labor taxes. The observation that the wedge is higher in continental Europe than in the United States has proved useful for understanding the extent to which taxes can explain differences in labor market outcomes. The observation that the ratio rises during recessions suggests some failure of competitive, market-clearing macroeconomic models at business cycle frequencies. The latter observation has guided recent research, including work on sticky wage models and job search models. (JEL E24, E32, J64)
A Black Swan in the Money Market
Authors: Taylor John B , Williams John C
Published: February 2009

The recent financial crisis saw a dramatic and persistent jump in interest rate spreads between overnight federal funds and longer-term interbank loans. The Fed took several actions to reduce these spreads including the creation of the Term Auction Facility (TAF). The effectiveness of these policies depends on the cause of the increased spreads such as counterparty risk, liquidity, or other factors. Using a no-arbitrage pricing framework and various measures of risk, we find robust evidence that increased counterparty risk contributed to the rise in spreads but do not find robust evidence that the TAF had a significant effect on spreads.
The Compromise Game: Two-Sided Adverse Selection in the Laboratory
Authors: Carrillo Juan D , Palfrey Thomas R
Published: February 2009

We analyze a game of two-sided private information where players have privately known “strengths” and can decide to fight or compromise. If either chooses to fight, the stronger player receives a high payoff and the weaker player receives a low payoff. If both choose to compromise, each player receives an intermediate payoff. The only equilibrium is for players to always fight. In our experiment, we observe frequent compromise, more fighting the lower the compromise payoff and less fighting by first than second movers. We explore several theories of cognitive limitations in an attempt to understand these anomalous findings. (JEL C91, D82)
The Origin of the Winner's Curse: A Laboratory Study
Authors: Charness Gary , Levin Dan
Published: February 2009

The Winner's Curse (WC) is a robust and persistent deviation from theoretical predictions established in experimental economics and claimed to exist in field environments. Recent attempts to reconcile such deviation include “cursed equilibrium” and level-k reasoning. We design and implement a simplified version of the Acquiring-a-Company game that transformed the game to an individual-choice problem that still retains the adverse-selection problem. We further simplified the problem so that simple ordinal reasoning could replace both Bayesian updating and contingent thinking. Our results suggest that the WC reflects bounded rationality in that people have difficulties performing contingent reasoning on future events. (JEL D81, D82)
The Geography of Trade in Online Transactions: Evidence from eBay and MercadoLibre
Authors: Hortaçsu Ali , Martínez-Jerez F. Asís , Douglas Jason
Published: February 2009

We analyze geographic patterns of trade between individuals using transactions data from eBay and MercadoLibre, two large online auction sites. We find that distance continues to be an important deterrent to trade between geographically separated buyers and sellers, though to a lesser extent than has been observed in studies of non-Internet commerce between business counterparties. We also find a strong “home bias” for trading with counterparties located in the same city. Further analyses suggest that location-specific goods such as opera tickets, cultural factors, and the possibility of direct contract enforcement in case of breach may be the main reasons behind the same-city bias. (JEL D44, F11, R12)
Technology's Edge: The Educational Benefits of Computer-Aided Instruction
Authors: Barrow Lisa , Markman Lisa , Rouse Cecilia Elena
Published: February 2009

We present results from a randomized study of a well-defined use of computers in schools, a popular instructional computer program for pre-algebra and algebra. We primarily assess the program using a test designed to target pre-algebra and algebra skills. Students randomly assigned to computer-aided instruction score significantly higher on a pre-algebra and algebra test than students randomly assigned to traditional instruction. We hypothesize that this effectiveness arises from increased individualized instruction as the effects appear larger for students in larger classes and in classes with high student absentee rates. (JEL H75, I21)
Telling Tales to End Wails: Narrative Therapy Techniques and Rehabilitation Counselling
Authors: Biggs Herbert C. , Hinton-Bayre Anton D.
Published: February 2009

Therapeutic intervention usually begins with a detailed description of the presenting problem and its antecedent history. Through the process of communicating their problem the client presents a story, potentially laden with their experiences, attitudes, beliefs and understandings. The topic and manner in which a story is relayed provides direct and indirect sources of information that help the therapist to both understand the client's problem and formulate goals and approaches to therapy. Rather than simply using the client's story as a guide to understanding and treatment, narrative therapy focuses on the client's story or ‘narrative’ as a medium through which change can be effected. During the process of narrative therapy the client is encouraged to deconstruct and critically appraise their story in the search for new meanings (White & Epston, 1990). The client is encouraged to retell their story with new language and new insights. Thus, the implementation of narrative therapy may be construed as a natural extension of taking the client's problem history, where the story told serves as the content foundation for the therapeutic process. The purpose of the present article is to provide a brief overview of narrative therapy techniques and their application in counselling.
Eating Attitudes, Self-Dissatisfaction and Emotional Distress Among Early Adolescents in Hawai'i: A Gender Comparison
Authors: Edman Jeanne L. , Yates Alayne , Aruguete Mara , Draeger John
Published: February 2009

The present study examines whether there are gender differences in eating attitudes among a sample of early adolescents in Hawai'i. A total of 79 female and 65 male 7th graders completed a survey that included measures of eating attitudes and other psychological constructs. Contrary to our prediction, males reported higher levels of disordered eating attitudes and body dissatisfaction than females. However, there were no gender differences in symptom levels of anxiety and depression. Eating attitudes were associated with symptoms of depression, anxiety and self-dissatisfaction among females, while only self-dissatisfaction was associated with eating attitudes among males. The findings fail to support past studies that suggest females report more disordered eating attitudes than males.
Twins Reared Apart: A Forgotten Case / Twin Research Reviews: X-Inactivation and Female Co-Twin Discordance for Hemophilia; Transplantation for Breast Reconstruction; Chimerism and Telomere Attrition in Dizygotic Twins; Divergent Life Histories in Twins Reared Apart / Current Concerns: High ACT-Scoring Twins; Dating a Twin; When Gender Identities Diverge / The Holland Twins
Authors: Segal Nancy L.
Published: February 2009

A forgotten story of monozygotic twins reared apart is described. The pair, born in 1941 in Fribourg, Switzerland, were separated due to switch-baby incident in the hospital. This caused one twin to be raised as a singleton by an unrelated family, and the other twin to be raised as a ‘dizygotic’ twin with an unrelated child. This is followed by reviews of recent twin research and case studies of X-inactivation and hemophilia, breast reconstruction, chimerism and life histories. The final section of the article includes human interest pieces on academic twins, dating twins, transsexual twins and athletic twins.
Flexible Mx Specification of Various Extended Twin Kinship Designs
Authors: Maes Hermine H. , Neale Michael C. , Medland Sarah E. , Keller Matthew C. , Martin Nicholas G. , Heath Andrew C. , Eaves Lindon J.
Published: February 2009

The extended twin kinship design allows the simultaneous testing of additive and nonadditive genetic, shared and individual-specific environmental factors, as well as sex differences in the expression of genes and environment in the presence of assortative mating and combined genetic and cultural transmission (Eaves et al., 1999). It also handles the contribution of these sources of variance to the (co)variation of multiple phenotypes. Keller et al. (2008) extended this comprehensive model for family resemblance to allow or a flexible specification of assortment and vertical transmission. As such, it provides a general framework which can easily be reduced to fit subsets of data such as twin-parent data, children-of-twins data, etc. A flexible Mx specification of this model that allows handling of these various designs is presented in detail and applied to data from the Virginia 30,000. Data on height, body mass index, smoking status, church attendance, and political affiliation were obtained from twins and their families. Results indicate that biases in the estimation of variance components depend both on the types of relative available for analysis, and on the underlying genetic and environmental architecture of the phenotype of interest.
Linkage Disequilibrium and Its Expectation in Human Populations
Authors: Sved John A.
Published: February 2009

Linkage disequilibrium (LD), the association in populations between genes at linked loci, has achieved a high degree of prominence in recent years, primarily because of its use in identifying and cloning genes of medical importance. The field has recently been reviewed by Slatkin (2008). The present article is largely devoted to a review of the theory of LD in populations, including historical aspects.
Paternal Alcoholism and Offspring ADHD Problems: A Children of Twins Design
Authors: Knopik Valerie S. , Jacob Theodore , Haber Jon Randolph , Swenson Lance P. , Howell Donelle N.
Published: February 2009

Objective:A recent Children-of-Female-Twin design suggests that the association between maternal alcohol use disorder and offspring ADHD is due to a combination of genetic and environmental factors, such as prenatal nicotine exposure. We present here a complementary analysis using a Children-of-Male-Twin design examining the association betweenpaternalalcoholism and offspring attention deficit hyperactivity problems (ADHP).Methods:Children-of-twins design: offspring were classified into 4 groups of varying genetic and environmental risk based on father and co-twin's alcohol dependence status.Results:Univariate results are suggestive of a genetic association between paternal alcohol dependence and broadly defined offspring ADHP. Specifically, offspring of male twins with a history of DSM-III-R alcohol dependence, as well as offspring of non-alcohol dependent monozygotic twins whose co-twin was alcohol dependent, were significantly more likely to exhibit ADHP than control offspring. However, multivariate models show maternal variables independently predicting increased risk for offspring ADHP and significantly decreased support for a genetic mechanism of parent-to-child transmission.Conclusions:In support of earlier work, maternal variables (i.e., maternal ADHD and prenatal exposure) were strongly associated with child ADHP; however, the role of paternal alcohol dependence influences was not definitive. While genetic transmission may be important, the association between paternal alcohol dependence and child ADHP is more likely to be indirect and a result of several pathways.
The Estimated Probability of Dizygotic Twins: A Comparison of Two Methods
Authors: Hardin Jill , Selvin Steve , Carmichael Suzan L. , Shaw Gary M.
Published: February 2009

This study presents a general model of two binary variables and applies it to twin sex pairing data from 21 twin data sources to estimate the frequency of dizygotic twins. The purpose of this study is to clarify the relationship between maximum likelihood and Weinberg's differential rule zygosity estimation methods. We explore the accuracy of these zygosity estimation measures in relation to twin ascertainment methods and the probability of a male. Twin sex pairing data from 21 twin data sources representing 15 countries was collected for use in this study. Maximum likelihood estimation of the probability of dizygotic twins is applied to describe the variation in the frequency of dizygotic twin births. The differences between maximum likelihood and Weinberg's differential rule zygosity estimation methods are presented as a function of twin data ascertainment method and the probability of a male. Maximum likelihood estimation of the probability of dizygotic twins ranges from 0.083 (95% approximate CI: 0.082, 0.085) to 0.750 (95% approximate CI: 0.749, 0.752) for voluntary ascertainment data sources and from 0.374 (95% approximate CI: 0.373, 0.375) to 0.987 (95% approximate CI: 0.959, 1.016) for active ascertainment data sources. In 17 of the 21 twin data sources differences of 0.01 or less occur between maximum likelihood and Weinberg zygosity estimation methods. The Weinberg and maximum likelihood estimates are negligibly different in most applications. Using the above general maximum likelihood estimate, the probability of a dizygotic twin is subject to substantial variation that is largely a function of twin data ascertainment method.
Modeling Extended Twin Family Data I: Description of the Cascade Model
Authors: Keller Matthew C. , Medland Sarah E. , Duncan Laramie E. , Hatemi Peter K. , Neale Michael C. , Maes Hermine H. M. , Eaves Lindon J.
Published: February 2009

The classical twin design uses data on the variation of and covariation between monozygotic and dizygotic twins to infer underlying genetic and environmental causes of phenotypic variation in the population. By using data from additional relative classes, such as parents, extended twin family designs more comprehensively describe the causes of phenotypic variation. This article introduces an extension of previous extended twin family models, the Cascade model, which uses information on twins as well as their siblings, spouses, parents, and children to differentiate two genetic and six environmental sources of phenotypic variation. The Cascade also relaxes assumptions regarding mating and cultural transmission that existed in previous extended twin family designs. The estimation of additional parameters and relaxation of assumptions is potentially important, not only because it allows more fine-grained descriptions of the causes of phenotypic variation, but more importantly, because it can reduce the biases in parameter estimates that exist in earlier designs.
Trends in the Probability of Twins and Males in California, 1983–2003
Authors: Hardin Jill , Carmichael Suzan L. , Selvin Steve , Shaw Gary M.
Published: February 2009

This study examines the probability of twins by birth year, maternal race–ethnicity, age, and parity and the influences of these demographic factors on the probability of male in twins and singletons in a large, racially diverse population. Recent publications note steep increases in twin births while the probability of male births has been reported to vary by parental race–ethnicity and age and birth order. Probability of male stratified by plurality has not been investigated in California prior to this study. Cubic spline estimates and Poisson regression techniques were employed to describe trends in twins and males using California vital statistics birth and fetal death records over the period from 1983–2003. This study includes 127,787 twin pair and 11,025,106 singleton births. The probability of twins varied by birth year, maternal race–ethnicity, age, and parity. The probability of twins increased by 10.1% from 1983–1992 and increased by 20.1% from 1993–2003, nearly doubling the previous increase. All maternal race–ethnicity groups showed increases in probability of twins with increasing maternal age. Parous women compared to nulliparous women had larger increases in the probability of twins. The probability of males in twins decreased from 1983–1992 and increased from 1993–2003; while in singletons the probability appeared unchanged. These findings show increases in the probability of twins in California from 1983–2003 and identify maternal age, race–ethnicity, and parity groups most likely to conceive twins. The cause of the increase in twins is unknown but coincides with trends towards delayed childbearing and increased use of subfertility treatments.
Virtual reality in theatre education and design practice new developments and applications
Authors: Kuksa Iryna
Published: February 2009

The global use of Information and Communication Technologies (ICTs) has already established new approaches to theatre education and research, shifting traditional methods of knowledge delivery towards a more visually enhanced experience, which is especially important for teaching scenography.
In this paper, I examine the role of multimedia within the field of theatre studies, with particular focus on the theory and practice of theatre design and education. I discuss various IT applications that have transformed the way we experience, learn and co-create our cultural heritage. I
explore a suite of rapidly developing communication and computer-visualization techniques that enable reciprocal exchange between students, theatre performances and artefacts. Eventually, I analyse novel technology-mediated teaching techniques that attempt to provide a new media platform for
visually enhanced information transfer. My findings indicate that the recent developments in the personalization of knowledge delivery, and also in student-centred study and e-learning, necessitate the transformation of the learners from passive consumers of digital products to active and
creative participants in the learning experience.
The United States and Iraq at cross purposes a historic overview
Authors: Terry Janice J
Published: February 2009

The United States and Iraq have alternately been good friends and enemies. In the 1980s, after the overthrow of Iran's Shah, the United States encouraged Iraq to wage war against the Islamic Republic. This was followed by arms, intelligence information and money. When the IranIraq war
ended, tensions between Baghdad and the Arab states increased. Some Arab states, especially Kuwait, demanded that Hussein should repay the wartime loans. Iraq argued that the money was not loaned but a gift to help fight the Persians. The United States was apparently neutral until Iraq invaded
Kuwait. Alarmed by the loss of Kuwaiti oil and perhaps even the fall of the Saudis, the United States launched the 1991 Gulf War. This was followed by 12 years of sanctions against Iraq and the Second Gulf War in 2003. For the last 5 years, the war on Iraq has resulted in the destabilization
of the Middle East. The author draws attention to the report of George McGovern and William Polk and agrees with its conclusions. Withdrawal of US armed forces from Iraq, positioning of an international police keeping force, reconstruction aid and the closing down of detention centres. Also,
the author believes that there will be no peace in the Middle East until there is a resolution of the Palestine/Israel conflict.