bluuebunny/crossref_metadata_2025 huggingface dataset:
A model for electric degradation of interconnect low-k dielectrics in microelectronic integrated circuits
Authors: Haase Gaddi S.
Published: February 2009

The low-k dielectric used in interconnect systems of advanced microelectronic devices tends to degrade faster than gate oxide under electric field. The scaling down of the spacing between metal lines to a few tens of nanometers in emerging complementary metal oxide semiconductor technologies calls for re-examining and refining of existing degradation models for ensuring the reliability of future technology nodes without compromising performance. This paper suggests a simple model to explain the nature of the field- and current-induced degradation by taking the electron temperature into account. It is based on experimentally observed trapped charge and current versus time behavior under constant voltage stress. The model explains the low observed activation energy but predicts its increase at operating conditions. It suggests that the commonly used E model may be too conservative for the extrapolation of dielectric lifetime measured under accelerated test (high voltage) conditions to operating voltages. It also predicts that the use of the recently proposed E model is safe for reliability engineering purposes, although it does not describe the full degradation process complexity adequately.
Field enhancement effect of nanocrystals in bandgap engineering of tunnel oxide for nonvolatile memory application
Authors: Lo Yun-Shan , Liu Ke-Chih , Cheng Cheng-Wei , Wu Jyun-Yi , Hou Cheng-Hao , Wu Tai-Bor
Published: February 2009

Charge storage characteristics of metal-oxide-semiconductor (MOS) structures containing Au nanocrystals on tunnel oxide composed of Al2O3/HfO2/Al2O3 stacks in different thickness piling up sequences were investigated. A significant enhancement of charge injection efficiency for both electrons and holes without sacrificing charge retention performance was found in the sample with a relatively thicker (∼3 nm) Al2O3 sublayer adjacent to Au nanocrystals and a thinner (∼1 nm) Al2O3 sublayer in front of the Si substrate. It is attributed to the local enhancement of electric field induced by the embedded Au nanocrystals, which greatly modifies the effective barrier of tunnel oxide.
Density functional approach for modeling CO2 pressurized polymer thin films in equilibrium
Authors: Talreja Manish , Kusaka Isamu , Tomasko David L.
Published: February 2009

We have used polymer density functional theory to analyze the equilibrium density profiles and interfacial properties of thin films of polymer in the presence of CO2. Surface tension, surface excess adsorption of CO2 on polymer surface, and width of the interface are discussed. We have shown the changes in these properties in the presence of CO2 and with increasing film thickness and their inverse linear relationship with increasing chain length. One of our important findings is the evidence of segregation of end segments toward the interface. We have introduced a new method of representing this phenomenon by means of Δ profiles that show increase in segregation owing to the presence of CO2 and with increasing chain length. We also make predictions for the octacosane-CO2 binary system near the critical point of CO2. Our results indicate qualitative trends that are comparable to the similar experimental and simulation studies.
An analysis of imprinted hysteresis loops for a ferroelectric Pb(Zr,Ti)O3 thin film capacitor using the switching transient current measurements
Authors: Kim Gun Hwan , Lee Hyun Ju , Jiang An Quan , Park Min Hyuk , Hwang Cheol Seong
Published: February 2009

This study examined the imprint mechanism of a ferroelectric Pt/Pb(Zr,Ti)O3(150-nm-thick)/Pt capacitor using pulse switching transient current measurements. The progression of the imprint was well explained by the propagation of a localized charge injection area, where there was an increase in coercive voltage and interfacial capacitance over the entire capacitor area. The as-received samples exhibited uniform interfacial capacitance over the total area. Charge injection resulted in a more rectified remanent polarization–applied voltage relationship compared with the as-received sample. Analytic functional forms for the switching charge and local switching area were also derived.
A parametric analysis of the density of states and intraband energy gaps in an ordered nanopore array diode laser
Authors: Verma V. B. , Coleman J. J.
Published: February 2009

We present a detailed analytical study of the effect of nanopore lattice geometry, material parameters, and temperature on the density of states and intraband energy gaps in an ordered nanopore array diode laser. An improved fabrication process is proposed to increase the peak gain achievable in the nanopore laser by a factor of 3 based on the simulation results.
Signal extraction using ensemble empirical mode decomposition and sparsity in pipeline magnetic flux leakage nondestructive evaluation
Authors: Chen Liang , Li Xing , Li Xun-bo , Huang Zuo-ying
Published: February 2009

The commonly used and cost effective corrosion inspection tools for the evaluation of pipelines utilize the magnetic flux leakage (MFL) technique. The MFL signal is usually contaminated by various noise sources. In this paper, we propose that the pipeline flaw MFL signal is extracted using the ensemble empirical mode decomposition (EEMD) and the sparsity. At first, we introduce the EEMD method. The EEMD defines the true intrinsic mode function (IMF) components as the mean of an ensemble of trials, each consisting of the signal plus a white noise of finite amplitude. Moreover, sparsity selection restriction was defined. Then, The MFL signal is decomposed into several IMFs used for signal reconstruction. Some modes are selected to reconstruct a new signal considering their sparsity. Finally, the comparison is made with the empirical mode decomposition. At the same time, the comparison of the selection restriction between the sparsity and the energy is described. The results show that the EEMD and the sparsity is an efficient technology with the pipeline flaw extraction.
Self-aligned placement of biologically synthesized Coulomb islands within nanogap electrodes for single electron transistor
Authors: Kumagai Shinya , Yoshii Shigeo , Matsukawa Nozomu , Nishio Kazuaki , Tsukamoto Rikako , Yamashita Ichiro
Published: February 2009

Biological synthesis and self-aligned placement of a Coulomb island was demonstrated for single electron transistor (SET) fabrication using a cage-shaped protein, apoferritin. Homogenous ϕ7 nm Co3O4 and In oxide nanoparticles (NPs) were synthesized utilizing the apoferritin cavity as a spatially restricted chemical reaction chamber. Apoferritin accommodating a NP (Co3O4, In oxide) showed specific affinity to a Ti surface and self-aligned itself between a pair of Au/Ti nanogap electrodes. After the protein cage was eliminated, two tunnel junctions between the NP and each electrode had the same gap, thereby forming an ideal SET structure. The produced SET exhibited a Coulomb-staircase/oscillation at 4.2 K.
The perfect quadruples model for electron correlation in a valence active space
Authors: Parkhill John A. , Lawler Keith , Head-Gordon Martin
Published: February 2009

A local approximation to the Schrödinger equation in a valence active space is suggested based on coupled cluster (CC) theory. Working in a pairing active space with one virtual orbital per occupied orbital, this perfect quadruples (PQ) model is defined such that electrons are strongly correlated up to “four-at-a-time” in up to two different (occupied-virtual) electron pairs. This is a truncation of the CC theory with up to quadruple substitutions (CCSDTQ) in the active space, such that the retained amplitudes in PQ are proportional to the fourth root of the number of CCSDTQ amplitudes. Despite the apparently drastic nature of the PQ truncation, in the cases examined this model is a very accurate approximation to complete active space self-consistent field. Examples include deformations of square H4, dissociation of two single bonds (water), a double bond (ethene), and a triple bond (nitrogen). The computational scaling of the model (fourth order with molecule size) is less than integral transformation, so relatively large systems can be addressed with improved accuracy relative to earlier methods such as perfect and imperfect pairing, which are truncations of CCSD in an active space.
Metal-enhanced bioluminescence: An approach for monitoring biological luminescent processes
Authors: Eltzov Evgeni , Prilutsky Daria , Kushmaro Ariel , Marks Robert S. , Geddes Chris D.
Published: February 2009

In this letter, the observation of metal (plasmon)-enhanced bioluminescence is reported. Bacteria, which are capable of generating specific bioluminescence signatures upon metabolic changes (general toxicity), have been studied from both glass and silvered glass microwell bottoms, where the silvered microwells have been modified with surface deposited silver island films (SiFs). The presence of the SiFs plasmon amplifies the near-field bioluminescence signatures, ≈<50 nm from the surface, enabling amplified detection of the reporter bioluminescence indicating sample toxicity. Using our approach a greater than fivefold enhancement in far-field bioluminescence occurs with much greater enhancements in the near-field predicted.
Optical microcavities on Si formed by self-assembled InGaAs/GaAs quantum dot microtubes
Authors: Vicknesh S. , Li F. , Mi Z.
Published: February 2009

We report on the fabrication and emission characteristics of InGaAs/GaAs quantum dot microtube ring resonators on Si substrates achieved using a simple but controllable substrate-on-substrate transfer process. We have observed three-dimensionally confined optical modes, including both radial and axial field distributions from quantum dot microtubes on Si with an engineered geometry at 77 K, which agrees well with results calculated using a photonic quasi-Schrödinger equation. An intrinsic Q-factor of ∼2000 is also derived.
A low-cost method of forming epitaxy SiGe on Si substrate by laser annealing
Authors: Ong C. Y. , Pey K. L. , Ong K. K. , Tan D. X. M. , Wang X. C. , Zheng H. Y. , Ng C. M. , Chan L.
Published: February 2009

In this letter, a low-cost alternative for forming high grade silicon germanium (SiGe) by a laser-induced crystallization of an amorphous Ge layer deposited directly on Si+ preamorphized implantation Si substrate is demonstrated. The results show that a fully strained epitaxial SiGe layer on the Si (100) substrate can be obtained at laser fluence above the epitaxial threshold. This is due to a liquid-phase epitaxial regrowth process of the laser annealing induced melted layer. Below the epitaxial threshold, polycrystalline SiGe is formed due to explosive recrystallization process. Simultaneous boron activation is achieved with the SiGe formation, a result due to the high temperature induced by the laser annealing.
Effects of thermal annealing on charge density and N chemical states in HfSiON films
Authors: Tanimura T. , Kamada H. , Toyoda S. , Kumigashira H. , Oshima M. , Liu G. L. , Liu Z. , Ikeda K.
Published: February 2009

We have investigated the charge density and N chemical states in HfSiON films annealed at various oxygen gas pressures by time-dependent photoemission spectroscopy. The Si 2p core-level spectra and the sample current reveal that annealing these films at low oxygen partial pressures affects the number of inherent fixed charges and annealing at high oxygen partial pressures results in a decrease in the number of trapped charges. The N 1s spectra of the annealed HfSiON samples indicate a decrease in Hf–N bonds due to the substitution of N by O along with a decrease in the number of trapped charges.
An Appetite for Yield: The Anatomy of the Subprime Mortgage Crisis
Authors: Ashton Philip
Published: February 2009

Whereas policy makers and industry advocates have hailed the growth of the subprime mortgage market in the US as evidence that financial innovation can more efficiently price and absorb credit risk, the 2007 mortgage crisis provides an opportunity to revisit the nature of financial risk. This paper employs a forensic analysis of the development of the subprime market from the 1980s through 2007 to argue that, in a competitive environment marked by the greater integration between housing finance and capital/equity markets, financial innovations provide new opportunities to hedge risk even as they collapse the barriers to rivalries between firms. This has changed the terrain for risk assessment, promoting new modes of financial competition that have intensified systemic risk and extended it to a widening set of firms, households, and communities.
Home Alone: The Individualization of Young, Urban Japanese Singles
Authors: Ronald Richard , Hirayama Yosuke
Published: February 2009

Social life in Japan has been historically orientated towards hierarchical networks of social integration starting in the family home and extending to the neighborhood, company, and nation. In the postwar period, households and life courses were largely fixed, mediated by company society, a standard breadwinner family model and an ascent up an owner-occupied housing ladder. The bursting of the economic bubble two decades ago, and the subsequent ‘lost decade’, disrupted established flows into employment, family life, and owner-occupation. We examine recent restructuring of life courses around the home which has become characteristic of social changes and a medium of individualization. The home, once ingrained with notions of the eternal Japanese family, has become a conduit of atomization for younger generations who have experienced radical shifts in social and economic conditions. Since the 1990s numbers of single-only and couple-only households have ballooned while marriage and fertility rates have declined. Although homeownership norms have persisted, new patterns of renting and single living in the city, or remaining in the family home as a ‘parasite single’, are increasing. We consider how the reconstitution of ‘home’ under more insecure housing and employment conditions is embedded with the reshaping of life courses, housing pathways, and patterns of urban space and living.
Facing Airport Security: Affect, Biopolitics, and the Preemptive Securitisation of the Mobile Body
Authors: Adey Peter
Published: February 2009

This paper explores how the mobile body and, specifically, the face have become a site of observation, calculation, prediction, and action in the process of moving across borders. The paper explores how in the circulatory space of the airport/border, the body's circulatory systems, biological rhythms, and affective expressions have become objects of suspicion—mobile surfaces from which inner thoughts and potentially hostile intentions are scrunitized, read, and given threatening meaning by the newest modes of airport security and surveillance. Examined according to the vectoral modes of historicity and virtual possibility, as well as the internal and external play of intention and feeling, the paper uncovers an increased attention to differential axes of mobility—of past and future, surface and interior. The paper situates these techniques within the preemptive biopolitical securitisation of mobility across borders which, it is argued, has found its referent object in the primal realm of affective capacities.
Sex on premises venue (SOPV) health promotion project in response to sustained increases in HIV notifications
Authors: Mullens Amy B. , Staunton Shaun , Debattista Joseph , Hamernik Elisabeth , Gill Darren
Published: February 2009

Background: Due to increases in HIV notifications in Queensland, a health promotion outreach project was developed with sex on premises venues (SOPV) in Brisbane. Methods: A health promotion officer (HPO) promoted safer sex behaviours among SOPV patrons over 14 months, including providing information, counselling and skills to enhance safer sexual behaviours and providing referrals. Surveys were introduced to facilitate discussions regarding HIV/sexually transmissible infections, testing and safer sex practices. Results: The project demonstrated feasibility within this highly sexualised environment, and was enhanced by careful monitoring and revising the procedure to improve patron/staff responses to the project. The introduction of a survey instrument was a significant contributor to the project’s effectiveness, providing opportunities for patrons to discuss a variety of key sexual health issues. Conclusions: This initiative reflected effective partnering between the Health Department, a community HIV/lesbian, gay, bisexual and transgender organisation and private industry. Despite initial difficulties, the presence of a health worker within an SOPV was acceptable to patrons and allowed for brief interventions to be conducted. This project was deemed effective for a limited time period and within certain constraints.
Novel approach to an effective community-based chlamydia screening program within the routine operation of a primary healthcare service
Authors: Buhrer-Skinner Monika , Muller Reinhold , Menon Arun , Gordon Rose
Published: February 2009

Background: A prospective study was undertaken to develop an evidence-based outreach chlamydia screening program and to assess the viability and efficiency of this complementary approach to chlamydia testing within the routine operations of a primary healthcare service. Methods: A primary healthcare service based in Townsville, Queensland, Australia, identified high-prevalence groups for chlamydia in the community. Subsequently, a series of outreach clinics were established and conducted between August 2004 and November 2005 at a defence force unit, a university, high school leavers’ festivities, a high school catering for Indigenous students, youth service programs, and backpacker accommodations. Results: All target groups were easily accessible and yielded high participation. Chlamydia prevalence ranged between 5 and 15% for five of the six groups; high school leavers had no chlamydia. All participants were notified of their results and all positive cases were treated (median treatment interval 7 days). Five of the six assessed groups were identified as viable for screening and form the basis for the ongoing outreach chlamydia screening program. Conclusion: The present study developed an evidence-based outreach chlamydia screening program and demonstrated its viability as a complementary approach to chlamydia testing within the routine operations of the primary healthcare service, i.e. without the need for additional funding. It contributes to the evidence base necessary for a viable and efficient chlamydia management program. Although the presented particulars may not be directly transferable to other communities or health systems, the general two-step approach of identifying local high-risk populations and then collaborating with community groups to access these populations is.
Risk reduction as an accepted framework for safer-sex promotion among women who have sex with women
Authors: Cox Peta , McNair Ruth
Published: February 2009

Background: Safer-sex information for women who have sex with women (WSW) is often very difficult to locate. Girl2girl.info is one of the only websites focussed on safer sex for WSW. The present article describes the predevelopment consultation and evaluation of girl2girl.info. A risk-reduction framework was used to develop the website. Methods: Girl2girl.info was developed in 2004 using questionnaires and focus groups with 36 consumers who were WSW, largely based in Canberra, Australia. In 2006–2007 the site was evaluated using mixed methods of questionnaires with 74 WSW and interviews with 17 health professionals around Australia. Results: This research has identified some key attitudes toward safer sex of WSW participants, in particular a misperception that the majority of WSW are at low risk for sexually transmissible infections and a consistent aversion to using latex for safer sex. Conclusions: The article concludes that the promotion of a risk-reduction approach – including non-latex-based safer-sex practices – for WSW is both a theoretically appropriate and engaging form of health promotion for WSW.
Performance of serological tests for syphilis in sexually transmitted diseases clinics in Guangxi Autonomous Region, China: implications for syphilis surveillance and control
Authors: Yin Yue-Ping , Wei Wan-Hui , Wang Hong-Chun , Zhu Bang-Yong , Yu Yan-Hua , Chen Xiang-Sheng , Peeling Rosanna W. , Cohen Myron S.
Published: February 2009

Background: China is experiencing a growing syphilis epidemic. Individuals are currently screened and cases are confirmed using traditional serological testing methods. Methods: A total of 11 558 serum specimens from patients at 14 sexually transmitted diseases (STD) clinics at provincial, prefecture and county levels in Guangxi Autonomous Region were tested at local clinics using the toluidine red unheated serum test (TRUST) and the SD Bioline Syphilis 3.0 Treponema Pallidum (SD-TP) test and then transported to the National STD Reference Laboratory for TRUST and confirmatory Treponema pallidum particle assay (TPPA) testing. Results: In local clinics, 13.2% of specimens were TRUST positive and 12.8% were TRUST and SD-TP positive. At the Reference Laboratory, 15.4% of specimens were TRUST positive and 11.8% were TRUST and TPPA positive. Local clinics showed a significantly higher prevalence of active syphilis compared with results from the Reference Laboratory (12.8 v. 11.8%, χ2 = 4.59, P = 0.03). The local TRUST tests had consistent results with Reference Laboratory tests qualitatively among 96.2% of the specimens and quantitatively among 95.5% of the specimens. The algorithm of TRUST screening and then SD-TP confirmation among positive TRUST specimens at local STD clinics had 96.6% sensitivity and 99.3% specificity in diagnosing active syphilis compared with the ‘gold standard’ based on TRUST and TPPA positivity at the Reference Laboratory (positive predictive value 95.1% and negative predictive value 99.5%). Conclusion: The TRUST screening and SD-TP confirmation in combination can be used at local STD clinics for the efficient diagnosis of serologically active syphilis. However, continuing capacity building and quality assurance remain critical in ensuring the quality of syphilis diagnosis at local clinics.
In vitro evaluation of the viability of vaginal cells (VK2/E6E7) and probiotic Lactobacillus species in lemon juice
Authors: Anukam Kingsley C. , Reid Gregor
Published: February 2009

Background: Women, especially in developing countries, most often bear the brunt of HIV infections. The continued lack of viable vaccines and microbicides has made some women resort to using natural products such as lemon or lime juice to avoid infection. Few in vitro studies have been done on the effect of lemon juice on vaginal cells and lactobacilli that constitute the major microbiota in healthy women. Objective: The objective of the present study was to evaluate in vitro the effect of lemon juice on the viability of vaginal cells (VK2/E6E7) and vaginal Lactobacillus species. Methods: Vaginal cells were exposed to different concentrations (0–30%) of lemon juice at pH 2.3 and 4.5 for 10 min. Viability was determined by staining the cells with propidium iodide and analysing them by flow cytometry. Lactobacillus organisms were dispensed into microplates with vaginally defined medium + peptone (VDMP) containing different concentrations of lemon juice ranging from 0 to 100%. Results: Lemon juice at pH 2.3 had a significant (P = 0.03) toxic effect on the vaginal cell line used. At 30% concentration, the vaginal cells were practically non-viable, typified by a 95% loss of viability, whereas at pH 4.5 there was only 5% cell loss. Lemon juice had varying growth inhibitory effects on the Lactobacillus species tested. At pH 4.5 and using 10–30% lemon juice, there was a stimulatory growth effect on certain Lactobacillus species. Conclusions: Lemon juice (20–30%) at pH 2.3 was highly toxic to VK2/E6E7 cells, and at pH 4.5 there was no significant effect on the viability of the cells within 10 min. Lemon juice above 10% at pH 2.3 was found to be detrimental to the growth of vaginal lactobacilli. Although lemon juice may be useful in other applications, its use in the vaginal region should be discouraged.
Sexually transmissible infections among sex workers and their clients: variation in prevalence between sectors of the industry
Authors: Seib Charrlotte , Debattista Joseph , Fischer Jane , Dunne Michael , Najman Jackob M.
Published: February 2009

Objectives: The risk of sexually transmissible infection (STI) among sex workers and their clients may be higher than the general population. However, many studies have categorised workers or clients into homogenous groups for the purposes of analysis. The aim of the present study was to assess variations in self-reported STI rates among licenced brothel, private and illegal sex workers and their clients. Methods: In 2003, self-report data were collected from female sex workers and their male commercial clients residing in the state of Queensland, Australia. Overall, 247 sex workers (aged 19–57 years) and 185 of their respective clients (aged between 19 and 72 years) completed anonymous questionnaires. Results: There was little variation in self-reported lifetime STI prevalence of licenced brothel, private and illegal (predominantly street-based) sex workers, although licenced brothel workers were less likely to report ever being diagnosed with gonorrhoea or pubic lice in the past (P = 0.035 and 0.004 respectively). In contrast, clients accessing illegal services reported higher lifetime STI (36.0%, 95% confidence interval (CI) 20.2–55.6) than men recruited through private sex workers (20.0%, 95% CI 11.4–32.5) and clients from licenced brothels (7.6%, 95% CI 3.7–14.5). Conclusions: This study found high self-reported lifetime prevalence of infection among sex workers and their clients. It is notable, however, that lower STI rates were reported by clients and sex workers from licenced brothels. This would suggest that risk of infection is not equivalent across industry sectors and highlights some of the inherent risks associated with generalisation across the sex industry.
Access to sexual health advice using an automated, internet-based risk assessment service
Authors: Lee David M. , Fairley Christopher K. , Sze Jun Kit , Kuo Tim , Cummings Rosey , Bilardi Jade , Chen Marcus Y.
Published: February 2009

Background: The present study aimed to determine the sexual risk profile of people using an automated, internet-based service that allows internet users to receive recommendations on sexually transmissible infection screening (‘Check your risk’ (CYR), http://www.checkyourrisk.org.au/), and to compare this with that of patients attending the Melbourne Sexual Health Centre (MSHC) for the first time over the same 6-month period: January–June 2006. Methods: The characteristics of those who used CYR and those who attended MSHC were compared using a χ2-test for categorical variables and the Mann–Whitney U-test for non-parametric data. Results: There were 2492 users who accessed CYR and 2735 who attended MSHC over the period. The age of CYR users was similar to that of MSHC patients when compared according to risk groups. The median number of recent sexual partners reported by CYR users was similar to and not significantly lower than that reported by MSHC patients. Of the 309 CYR users who provided a rating for the CYR site, 215 (70%) rated it as being ‘useful’ to ‘very useful’. Conclusions: Individuals who accessed an automated, internet-based sexual risk assessment service were at substantial risk for sexually transmitted infections, similar to those attending a sexual health service.
Vulval Crohn's disease
Authors: Edmiston Natalie , Ooi Catriona , Otton Geoffrey , Boyle Michael
Published: February 2009

We report a case of vulval Crohn’s disease, the diagnosis of which was complicated by the presence of sexually transmissible infections.
Rapidly ageing HIV epidemic among men who have sex with men in Australia
Authors: Murray John M. , McDonald Ann M. , Law Matthew G.
Published: February 2009

Background: Antiretroviral therapy has increased survival for individuals living with HIV and has led to an ageing of this population in developed countries. To date the rate of ageing has been unquantified, giving rise to uncertainty in the treatment emphasis and burden in this population. Methods: A mathematical model was used in conjunction with HIV/AIDS data from the Australian National HIV/AIDS Registry to estimate numbers and ages of Australian men who have sex with men (MSM) living with HIV infection from 1980 to 2005. Results: The average age of HIV-infected Australian MSM is estimated to exceed 44 years of age by the year 2010 and has increased by 1 year of age for each two calendar years since the mid-1980s. HIV-infected MSM over 60 years of age have been increasing in number by 12% per year since 1995. A consequence of successful therapy with subsequent ageing of those infected has meant that from 2001 estimated deaths from other causes exceed AIDS deaths in Australia. Conclusions: In summary, our analyses indicate an increasing and rapidly ageing population living with HIV in Australia. This will inevitably lead to more serious non-AIDS conditions in ageing patients living with HIV, and to increased treatment complexity.
Importance of promoting HIV testing for preventing secondary transmissions: modelling the Australian HIV epidemic among men who have sex with men
Authors: Wilson David P. , Hoare Alexander , Regan David G. , Law Matthew G.
Published: February 2009

Background: We address the research questions: (i) what proportion of new HIV infections is transmitted from people who are (a) undiagnosed, (b) in primary HIV infection (PHI), (c) on antiretroviral therapy?; and (ii) what is the expected epidemiological impact of (a) increasing the proportion of newly acquired HIV infections receiving early treatment, and (b) increasing HIV testing rates? Methods: We used a mathematical model to simulate HIV transmission in the population of men who have sex with men (MSM) in Australia. We calibrated the model using established biological and clinical data and a wide range of Australian MSM epidemiological and behavioural data sources. Results: We estimate that ~19% of all new HIV infections are transmitted from the ~3% of Australian HIV-infected MSM who are in PHI; ~31% of new HIV infections are estimated to be transmitted from the ~9% of MSM with undiagnosed HIV. We estimate that the average number of infections caused per HIV-infected MSM through the duration of PHI is ~0.14–0.28. Conclusions: The epidemiological impact of increasing treatment in PHI would be modest due to insufficient detection of newly-infected individuals. In contrast, increases in HIV testing rates could have substantial epidemiological consequences. The benefit of testing will also increase over time. Promoting increases in the coverage and frequency of testing for HIV could be a highly-effective public health intervention, but the population-level impact of interventions based on promoting early treatment of patients diagnosed in PHI is likely to be small. Treating PHI requires further evaluation of its long-term effects on HIV-infected individuals.
Endangered minority and regional languages (‘dialects’) in Italy
Authors: Coluzzi Paolo
Published: February 2009

The Italian linguistic situation is characterised by a remarkable number of language varieties, although the development of Italian in the past 150 years has been the cause of a language shift from local languages to Italian. The degree of endangerment suffered by so-called ‘Italian dialects’ is shown using theMajor Evaluative Factors of Language Vitalitydrawn up by a UNESCO ad hoc expert group in 2003, and the data offered by the 2006 ISTAT survey on language use. The debate in Italy on the vitality of ‘dialects’ and their future has done little to activate mechanisms and strategies to reverse the worrying language shift that both minority languages and ‘dialects’ are undergoing.
The making of ‘proper’ homes: Everyday practices in migrant domestic work in Naples
Authors: Näre Lena
Published: February 2009

Changing from a country of emigration into one of immigration has been one of the major phenomena of Italian society in recent years. One of the realms where this has been most evident is in Italian households employing migrants for domestic service and care work. This article looks at domestic and care practices in the everyday life of a Neapolitan household. Based on participant observation conducted in Giuseppe's apartment, it shows how the traditional Neapolitan way of life can be maintained by employing a live-in worker. It discusses some of the contradictions and tensions involved in this kind of work, and, by looking at everyday life, it also questions depictions of vulnerable migrant workers at the mercy of their employers.
Sociology of the stumbling-block: A profile of Alessandro Pizzorno
Authors: Di Mascio Fabrizio
Published: February 2009

‘But he has nothing on!’ Throughout his career, the Italian sociologist Alessandro Pizzorno's sophisticated and penetrating sociological analysis has laid bare the shortcomings of the theoretical ‘new clothes’ woven by methodological individualism out of concepts of ‘individual’, ‘interest’, ‘decision’. As well as articulating Pizzorno's critique, this article aims to draw attention to the substantial and skilfully designed suit of theoretical clothes in which he has dressed the naked emperor. Pizzorno calls on sociologists to pay particular attention to processes of mutual recognition and attribution of identity: these processes, Pizzorno argues, give standards of value to the individuals involved, who are seen as ‘jealous of their reputation’ rather than as utility maximisers.
Valerie Horsley: Getting under the skin
Authors: Short Ben
Published: February 2009

Valerie Horsley investigates the regulation and differentiation of stem cells in mammalian skin.
Identification of cell cycle–arrested quiescent osteoclast precursors in vivo
Authors: Mizoguchi Toshihide , Muto Akinori , Udagawa Nobuyuki , Arai Atsushi , Yamashita Teruhito , Hosoya Akihiro , Ninomiya Tadashi , Nakamura Hiroaki , Yamamoto Yohei , Kinugawa Saya , Nakamura Midori , Nakamichi Yuko , Kobayashi Yasuhiro , Nagasawa Sakae , Oda Kimimitsu , Tanaka Hirofumi , Tagaya Mitsuo , Penninger Josef M. , Ito Michio , Takahashi Naoyuki
Published: February 2009

Osteoclasts are multinucleated cells that resorb bone. Although osteoclasts originate from the monocyte/macrophage lineage, osteoclast precursors are not well characterized in vivo. The relationship between proliferation and differentiation of osteoclast precursors is examined in this study using murine macrophage cultures treated with macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB (RANK) ligand (RANKL). Cell cycle–arrested quiescent osteoclast precursors (QuOPs) were identified as the committed osteoclast precursors in vitro. In vivo experiments show that QuOPs survive for several weeks and differentiate into osteoclasts in response to M-CSF and RANKL. Administration of 5-fluorouracil to mice induces myelosuppression, but QuOPs survive and differentiate into osteoclasts in response to an active vitamin D3 analogue given to those mice. Mononuclear cells expressing c-Fms and RANK but not Ki67 are detected along bone surfaces in the vicinity of osteoblasts in RANKL-deficient mice. These results suggest that QuOPs preexist at the site of osteoclastogenesis and that osteoblasts are important for maintenance of QuOPs.
WldS protein requires Nmnat activity and a short N-terminal sequence to protect axons in mice
Authors: Conforti Laura , Wilbrey Anna , Morreale Giacomo , Janeckova Lucie , Beirowski Bogdan , Adalbert Robert , Mazzola Francesca , Di Stefano Michele , Hartley Robert , Babetto Elisabetta , Smith Trevor , Gilley Jonathan , Billington Richard A. , Genazzani Armando A. , Ribchester Richard R. , Magni Giulio , Coleman Michael
Published: February 2009

The slow Wallerian degeneration (WldS) protein protects injured axons from degeneration. This unusual chimeric protein fuses a 70–amino acid N-terminal sequence from the Ube4b multiubiquitination factor with the nicotinamide adenine dinucleotide–synthesizing enzyme nicotinamide mononucleotide adenylyl transferase 1. The requirement for these components and the mechanism of WldS-mediated neuroprotection remain highly controversial. The Ube4b domain is necessary for the protective phenotype in mice, but precisely which sequence is essential and why are unclear. Binding to the AAA adenosine triphosphatase valosin-containing protein (VCP)/p97 is the only known biochemical property of the Ube4b domain. Using an in vivo approach, we show that removing the VCP-binding sequence abolishes axon protection. Replacing the WldS VCP-binding domain with an alternative ataxin-3–derived VCP-binding sequence restores its protective function. Enzyme-dead WldS is unable to delay Wallerian degeneration in mice. Thus, neither domain is effective without the function of the other. WldS requires both of its components to protect axons from degeneration.
WldS requires Nmnat1 enzymatic activity and N16–VCP interactions to suppress Wallerian degeneration
Authors: Avery Michelle A. , Sheehan Amy E. , Kerr Kimberly S. , Wang Jing , Freeman Marc R.
Published: February 2009

Slow Wallerian degeneration (WldS) encodes a chimeric Ube4b/nicotinamide mononucleotide adenylyl transferase 1 (Nmnat1) fusion protein that potently suppresses Wallerian degeneration, but the mechanistic action of WldS remains controversial. In this study, we characterize WldS-mediated axon protection in vivo using Drosophila melanogaster. We show that Nmnat1 can protect severed axons from autodestruction but at levels significantly lower than WldS, and enzyme-dead versions of Nmnat1 and WldS exhibit severely reduced axon-protective function. Interestingly, a 16–amino acid N-terminal domain of WldS (termed N16) accounts for the differences in axon-sparing activity between WldS and Nmnat1, and N16-dependent enhancement of Nmnat1-protective activity in WldS requires the N16-binding protein valosin-containing protein (VCP)/TER94. Thus, WldS-mediated suppression of Wallerian degeneration results from VCP–N16 interactions and Nmnat1 activity converging in vivo. Surprisingly, mouse Nmnat3, a mitochondrial Nmnat enzyme that localizes to the cytoplasm in Drosophila cells, protects severed axons at levels indistinguishable from WldS. Thus, nuclear Nmnat activity does not appear to be essential for WldS-like axon protection.
Mitochondrial outer and inner membrane fusion requires a modified carrier protein
Authors: Hoppins Suzanne , Horner Jennifer , Song Cheng , McCaffery J. Michael , Nunnari Jodi
Published: February 2009

In yeast, three proteins are essential for mitochondrial fusion. Fzo1 and Mgm1 are conserved guanosine triphosphatases that reside in the outer and inner membranes, respectively. At each membrane, these conserved proteins are required for the distinct steps of membrane tethering and lipid mixing. The third essential component is Ugo1, an outer membrane protein in the mitochondrial transport protein family. We show that Ugo1 is a modified member of this family, containing three transmembrane domains and existing as a dimer, a structure that is critical for the fusion function of Ugo1. Our functional analysis of Ugo1 indicates that it is required distinctly for both outer and inner membrane fusion after membrane tethering, indicating that it operates at the lipid-mixing step of fusion. This role is distinct from the fusion dynamin-related proteins and thus demonstrates that at each membrane, a single fusion protein is not sufficient to drive the lipid-mixing step, but instead, this step requires a more complex assembly of proteins.
Mitochondrial membrane biogenesis: phospholipids and proteins go hand in hand
Authors: Gohil Vishal M. , Greenberg Miriam L.
Published: February 2009

Mitochondrial membrane biogenesis requires the import and synthesis of proteins as well as phospholipids. How the mitochondrion regulates phospholipid levels and maintains a tight protein-to-phospholipid ratio is not well understood. Two recent papers (Kutik, S., M. Rissler, X.L. Guan, B. Guiard, G. Shui, N. Gebert, P.N. Heacock, P. Rehling, W. Dowhan, M.R. Wenk, et al. 2008. J. Cell Biol. 183:1213–1221; Osman, C., M. Haag, C. Potting, J. Rodenfels, P.V. Dip, F.T. Wieland, B. Brügger, B. Westermann, and T. Langer. 2009. J. Cell Biol. 184:583–596) identify novel regulators of mitochondrial phospholipid biosynthesis. The biochemical approach of Kutik et al. (2008) uncovered an unexpected role of the mitochondrial translocator assembly and maintenance protein, Tam41, in the biosynthesis of cardiolipin (CL), the signature phospholipid of mitochondria. The genetic analyses of Osman et al. (2009) led to the discovery of a new class of mitochondrial proteins that coordinately regulate CL and phosphatidylethanolamine, another key mitochondrial phospholipid. These elegant studies highlight overlapping functions and interdependent roles of mitochondrial phospholipid biosynthesis and protein import and assembly.
A Lie-theoretic construction of some representations of the degenerate affine and double affine Hecke algebras of type 𝐵𝐶_{𝑛}
Authors: Etingof Pavel , Freund Rebecca , Ma Xiaoguang
Published: February 2009

Let

G
=
G
L
(
N
)

G=GL(N)

,

K
=
G
L
(
p
)
×
G
L
(
q
)

K=GL(p)\times GL(q)

, where

p
+
q
=
N

p+q=N

, and let

n
n

be a positive integer. We construct a functor from the category of Harish-Chandra modules for the pair

(
G
,
K
)

(G,K)

to the category of representations of the degenerate affine Hecke algebra of type

B
n

B_n

, and a functor from the category of

K
K

-monodromic twisted

D
D

-modules on

G

/

K

G/K

to the category of representations of the degenerate double affine Hecke algebra of type

B

C
n

BC_n

; the second functor is an extension of the first one.
StowawayMITEs inHordeum(Poaceae): evolutionary history, ancestral elements and classification
Authors: Petersen Gitte , Seberg Ole
Published: February 2009

Given the lack of direct observational data relating to transposition ofStowawayminiature inverted repeat transposable elements, phylogenetic methods may provide a means of generating data that adds to our knowledge of these elements. In a phylogenetic framework the evolutionary history of homologous elements may be traced, and the nucleotide sequence of elements at or close to the time of insertion can be reconstructed. Based on a phylogeny of the diploid species of the genusHordeumwe explore evolutionary aspects of four non‐homologous groups ofStowawayelements inserted into three nuclear genes: nucellin, xylose isomerase, and barley leucine zipper 1. The data illustrate how elements starting from a high degree of sequence similarity between terminal inverted repeat regions gradually degrade, and confirm previous notions about preferential insertion at particular TA target sites. It is shown how creation of consensus sequences as estimates of ancestral elements may be positively misleading. TheStowawayfamily of transposable elements is often further divided into subfamilies based on sequence similarity between elements. Sequence similarity data from the elements discovered in the xylose isomerase gene, and other elements found through BLAST searches in GenBank, reveal inconsistency in the rules used for classification. In order to reflect natural groups, a classification of transposable elements must be based on phylogenetic evidence rather than raw similarity. © The Willi Hennig Society 2009.
Pastoralist’s livestock and settlements influence game bird diversity and abundance in a savanna ecosystem of southern Kenya
Authors: Morris Dana L. , Western David , Maitumo David
Published: February 2009

We investigated the vegetation structure and density of game birds along a successional gradient created by varying intensity of human settlement in a pastoral community in Shompole group ranch in southern Kenya. We examined four habitat types including heavily‐grazed grass in currently occupied settlements, short grass in seasonal settlements, patches of bushed woodland in settlement sites that had been abandoned up to 30 years ago, and tall grass in a wildlife sanctuary. Vegetation biomass was the highest in the sanctuary where livestock are excluded and the lowest in the vicinity of currently occupied settlements. Abundance of doves (Oena spp. and Streptopelia spp.) was best associated with moderate grazing and per cent green grass, which provide good foraging opportunities. Francolin and spurfowl (Francolinus spp.) were positively associated with vegetation biomass. Quail (Coturnix spp.) were positively associated with tree cover. These data reflect the importance of maintaining a balance of wildlife and livestock grazing with patches of ungrazed grasslands and bushed woodlands in providing a mosaic of habitats that support a diverse population of game birds. The results have wide application for an integrated management approach to livestock, wildlife and game bird management in the savannas.
Effects of habitat disturbance and food supply on population densities of three primate species in the Kakamega Forest, Kenya
Authors: Mammides Christos , Cords Marina , Peters Marcell K.
Published: February 2009

While habitat disturbance and food availability are major factors thought to determine the abundance of primates, evidence for their importance is uneven. We assessed the effects of these factors on three monkey species, guerezas (Colobus guereza), blue monkeys (Cercopithecus mitis) and redtails (Cercopithecus ascanius), in four areas of the Kakamega Forest, Kenya. Group densities of guerezas and blue monkeys were higher in areas where disturbance levels were also higher. Food availability measured as basal area density of food trees did not correlate significantly with the group densities of any of the three monkeys. The diversity of food trees, another potential measure of food abundance did, however, correlate with group densities of guerezas and blue monkeys suggesting that food availability may positively influence monkey density, and may sometimes increase with disturbance. Group densities of redtails did not correlate with any habitat variable examined, suggesting that factors other than those we considered may have influenced the abundance of this species particularly.