bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of GaN on Si(111): Surfaces and crystallinity of the epifilms and the transport behavior of GaN/Si heterojunctions
Authors: Xu Zhongjie , Zhang Lixia , He Hongtao , Wang Jiannong , Xie Maohai
Published: November 2011

Growths of GaN on Si(111) – (7 × 7) substrates by plasma-assisted molecular-beam epitaxy (PA-MBE) have been studied. Optimal conditions of MBE and the effect of a low-temperature (LT) buffer are followed. It is found that irrespective of the growth conditions and the growth strategies (direct versus two-step growth), a thin amorphous-like interface layer always forms. For smooth surfaces and better crystallinity of the epifilms, a LT-buffer preceding the high-temperature deposition is helpful, and the grown GaN films are of nitrogen-polar. Transport measurements of the heterojunctions of GaN on heavily p- and n-doped Si reveal ohmic behavior, whereas that of n-GaN on lightly doped n−-Si substrate shows rectifying characteristics.
Surface effect on resistive switching behaviors of ZnO
Authors: Ke Jr-Jian , Liu Zi-Jheng , Kang Chen-Fang , Lin Su-Jien , He Jr-Hau
Published: November 2011

The interaction between chemisorbed oxygen adatoms (O2(ad)−) and oxygen vacancies associated with the formation/rupture of conductive filaments dominates the switching yield of ZnO, which is also confirmed by the fact that the reduction of SET/RESET voltage with the temperature. The pronounced surface effect-induced conductivity lowering due to O2(ad)− chemisorption leads to increased resistance of high resistance state (HRS). The current decay of the HRS with increased temperatures/times is owing to the severe O2(ad)− chemisorption as Joule heating is continuously applied. The statistical analysis for over 400 cells provides essential evidence for evaluating the surface effect on resistive switching.
Probing the metal-insulator transition of NdNiO3 by electrostatic doping
Authors: Son Junwoo , Jalan Bharat , Kajdos Adam P. , Balents Leon , James Allen S. , Stemmer Susanne
Published: November 2011

Modulation of the charge carrier density in a Mott material by remote doping from a highly doped conventional band insulator is proposed to test theoretical predictions of band filling control of the Mott metal-insulator transition without introducing lattice distortions or disorder, as is the case for chemical doping. The approach is experimentally tested using ultrathin (2.5 nm) NdNiO3 films that are epitaxially grown on La-doped SrTiO3 films. We show that remote doping systematically changes the charge carrier density in the NdNiO3 film and causes a moderate shift in the metal-insulator transition temperature. These results are discussed in the context of theoretical models of this class of materials exhibiting a metal-insulator transition.
Ultra-high four wave mixing efficiency in slot waveguides with silicon nanocrystals
Authors: Trita A. , Lacava C. , Minzioni P. , Colonna J.-P. , Gautier P. , Fedeli J.-M. , Cristiani I.
Published: November 2011

We report on wavelength conversion through four-wave-mixing in silicon slot-waveguides with embedded silicon nanocrystals. The combination of strong optical confinement and Si:nc nonlinearity provides a huge waveguide nonlinear coefficient γ = 1100 W−1m−1. Moreover, the improvement in the fabrication procedure allowed a loss reduction with respect to previous reported structures, enabling the achievement of an extreme value for the conversion efficiency which represents the best result ever reported in the scientific literature.
High performance bulk metallic glass/carbon nanotube composite cathodes for electron field emission
Authors: Hojati-Talemi Pejman , Gibson Mark A. , East Daniel , Simon George P.
Published: November 2011

We report the preparation of new nanocomposites based on a combination of bulk metallic glass and carbon nanotubes for electron field emission applications. The use of bulk metallic glass as the matrix ensures high electrical and thermal conductivity, high thermal stability, and ease of processing, whilst the well dispersed carbon nanotubes act as highly efficient electron emitters. These advantages, alongside excellent electron emission properties, make these composites one of the best reported options for electron emission applications to date.
Crystallization behavior and high temperature magnetic phase transitions of Nb-substituted FeCoSiBCu nanocomposites
Authors: Roy R. K. , Kernion S. J. , Shen S. , McHenry M. E.
Published: November 2011

The effect of Nb substitution on the nanocrystallization process and high temperature magnetic properties of FeCoSiBCu nanocomposites is reported. Magnetization changes accompany the primary crystallization of α-Fe(Co) nanocrystals and the secondary crystallization of (FeCo)23B6 and (FeCo)2B phases. With increasing the Nb fraction in the alloys, the diffusion barrier to growth of α-Fe(Co) nanocrystals increases, resulting in an increase of thermal stability and a delay of Fe(Co) dissolution required for (FeCo)23B6 phase formation. The transmission electron microscopy images reveal finer grains with increasing Nb content.
Annealing of silicon optical fibers
Authors: Gupta N. , McMillen C. , Singh R. , Podila R. , Rao A. M. , Hawkins T. , Foy P. , Morris S. , Rice R. , Poole K. F. , Zhu L. , Ballato J.
Published: November 2011

The recent realization of silicon core optical fibers has the potential for novel low insertion loss rack-to-rack optical interconnects and a number of other uses in sensing and biomedical applications. To the best of our knowledge, incoherent light source based rapid photothermal processing (RPP) was used for the first time to anneal glass-clad silicon core optical fibers. X-ray diffraction examination of the silicon core showed a considerable enhancement in the length and amount of single crystallinity post-annealing. Further, shifts in the Raman frequency of the silicon in the optical fiber core that were present in the as-drawn fibers were removed following the RPP treatment. Such results indicate that the RPP treatment increases the local crystallinity and therefore assists in the reduction of the local stresses in the core, leading to more homogenous fibers. The dark current-voltage characteristics of annealed silicon optical fiber diodes showed lower leakage current than the diodes based on as-drawn fibers. Photons in UV and vacuum ultraviolet (VUV) regions play a very important role in improving the bulk and carrier transport properties of RPP-treated silicon optical fibers, and the resultant annealing permits a path forward to in situ enhancement of the structure and properties of these new crystalline core optical fibers.
Dye-sensitized solar cells with modified TiO2 surface chemical states: The role of Ti3+
Authors: Yu Yang , Wu Kunjie , Wang Deliang
Published: November 2011

Dye-sensitized solar cells (DSSCs) with TiO2 electrodes, which were modified to have different surface chemical states, were fabricated. The DSSCs had an ultra-flat TiO2 electrode, on which only a mono-layer dye was attached. The cell I-V measurement showed that Ti3+ ion had a dramatic effect on cell performance. The efficiency of a DSSC was shown to have a strong correlation with the concentration of the Ti3+ surface state, it decreased almost linearly with increased Ti3+ concentration. The oxygen vacancy-Ti3+ defect served as electron recombination center and decreased both the open-circuit voltage and the fill factor.
Oscillatory quantum screening effects on the positronium (Ps) formation in quantum plasmas
Authors: Kim Chang-Geun , Jung Young-Dae
Published: November 2011

The oscillatory quantum screening effects on the positronium formation by the positron are investigated in quantum plasmas. It is found that the oscillatory screening effects suppress the positronium formation radius as well as the positronium formation cross section. It is also found that the positronium formation radius decreases with increasing quantum wave number. It is found that the peak position of the differential cross section is receded from the projectile with decreasing quantum wave number. In addition, the oscillatory screening effects on the positronium formation cross section are found to be decreased with an increase of the collision energy.
Low levels of uptake of free interpreters by Australian doctors in private practice: secondary analysis of national data
Authors: Phillips Christine B. , Travaglia Joanne
Published: November 2011

Background. One in thirty-five Australians has poor proficiency in English, and may need language support in health consultations. Australia has the world’s most extensive system of fee-free provision of interpreters for doctors, but the degree of uptake relative to need is unknown. Objective. To assess the current unmet and projected future needs for interpreters in Australia in Medicare-funded medical consultations. Method. Secondary analysis of Australian Census, Medicare and Translating and Interpreting Service (TIS) datasets. Age-specific rates of non-Indigenous populations who had self-reported poor proficiency in English were applied to age-specific attendances to general practitioners (GPs) and private specialists to estimate the need for language-assisted consultations in 2006–07. The proportion of services where language assistance was used when needed was estimated through aggregate data from the Medicare and TIS datasets. Results. We estimate that interpreters from the national fee-free service were used for patients with poor proficiency in English is less than 1 in 100 (0.97%) Medicare-funded consultations. The need for interpreters will escalate in future, particularly among those over 85 years. Discussion. Doctors currently underuse interpreters. Increasing the use of interpreters requires education and incentives, but also sustained investment in systems, infrastructure and interpreters to meet the escalation in demand as the population ages. What is known about this topic? Australia is a multilingual country, with 1 in 35 Australians rating their spoken English as poor. Australia is regarded internationally as a model of service provision in its national fee-free rapid-access telephone interpreter service (the Doctors Priority Line) for doctors charging Medicare-rebateable services. Little is known of the extent of uptake of interpreter services by private doctors, relative to estimated patient need. What does this paper add? Using estimates generated from Medicare statistics, Translating and Interpreting Service statistics and rates calculated from ABS data on language proficiency, we estimate that for every 100 people with poor English proficiency who see a private GP or specialist, only 1 will have an interpreter from the free Doctors Priority Line. Although there are interpreter services funded by States and Territories, these are used very infrequently by GPs and consultants in private practice. The demand for interpreters will increase in future as the population ages. What are the implications for practitioners? Even with a free, rapid-access service, doctors underuse interpreters. Public policy should focus on both education and financial incentives to encourage doctors to use interpreters. Future increases in demand for interpreters will require sustained input into developing the interpreter workforce, and training healthcare practitioners and their businesses to be proactive about using interpreters.
The state of physical environments in Australian residential aged care facilities
Authors: Moore Kirsten J. , Hill Keith D. , Robinson Andrew L. , Haines Terry P. , Haralambous Betty , Nitz Jennifer C.
Published: November 2011

Objective.
This paper examines the quality and safety of the physical environment in Australian residential aged care facilities (RACFs).

Design.
Cross-sectional study. One assessor completed environmental audits to identify areas of the physical environment that needed to be addressed to improve the wellbeing and safety of residents.

Setting.
Nine RACFs participating in a broader falls prevention project were audited. RACFs were located in Queensland, Tasmania or Victoria and were chosen by convenience to represent high level, low level, dementia and psychogeriatric care, regional and metropolitan facilities, small and large facilities and a culturally specific facility.

Main outcome measure.
An environmental audit tool was adapted from a tool designed to foster older person friendly hospital environments. The tool consisted of 147 items.

Results.
Across all sites 450 items (34%) required action. This ranged from 21 to 44% across sites. The audit domains most commonly requiring action included signage, visual perception and lighting, and outdoor areas.

Conclusions.
Although not representative of all residential facilities in Australia, this audit process has identified common environmental problems across a diverse mix of residential care facilities. Results highlight the need for further investigation into the quality of physical environments, and interventions to improve physical environments in Australian RACFs.

What is known about the topic?
Despite the importance of the physical environment on the health, wellbeing and safety of older people in residential aged care facilities, few studies have comprehensively evaluated the physical environment in facilities in Australia.

What does this paper add?
This paper provides findings from comprehensive audits of nine residential aged care facilities representing a broad range of facility settings in terms of location, level and type of care and target population. Findings indicate that each facility had at least 21% of items requiring action with an average of 34% of items requiring action across all facilities.

What are the implications for practitioners?
There is a need to undertake intermittent, thorough assessments of the physical environments in which residents live and, if applicable, implement strategies or modifications to improve the environment. Areas requiring particular consideration may be lighting, colour contrasts, signage and outdoor areas.
Complex health service needs for people who are homeless
Authors: Moore Gaye , Manias Elizabeth , Gerdtz Marie Frances
Published: November 2011

Background. Homeless people face many challenges in accessing and utilising health services to obtain psychosocial supports offered in hospital and community settings. The complex nature of health issues is compounded by lack of accessibility to services and lack of appropriate and safe housing. Objective. To examine the perceptions and experiences of homeless people in relation to their health service needs as well as those of service providers involved with their care. Design. A purposive sampling approach was undertaken with a thematic framework analysis of semi-structured interviews. Participants. Interviews were undertaken with 20 homeless people who accessed the emergency department in an acute hospital in Melbourne, Australia and 27 service providers involved in hospital and community care. Results. Six key themes were identified from interviews: complexity of care needs, respect for homeless people and co-workers, engagement as a key strategy in continued care, lack of after-hour services, lack of appropriate accommodation and complexity of services. Conclusions. Findings revealed the complex and diverse nature of health concerns in homeless people. The demand on hospital services continues to increase and unless government policies take into consideration the psychosocial demands of the communities most vulnerable people efforts to divert hospital demand will continue to fail. What is known about the topic? Homeless people have complex healthcare needs and are high users of emergency departments (EDs). The increasing demand on hospital services has led to a focus by the Australian State, Territory and Federal Governments on strategies to divert homeless people from presenting to the ED. What does this paper add? This paper gives an insight into the experiences of homeless people and health service provides who are directly involved in their care. This insight gives important focus on the health needs and service responses that currently exist and the ongoing challenges that face homeless people and the health professionals responding to those needs. What are the implications for practitioners? To adequately respond to the needs of homeless people safe and supportive accommodation is a crucial component of services required to try and break the cycle of representation to the emergency department. Individual engagement strategies with coordinated care between hospital and community are required to address the complex care needs and psychosocial issues.
Growth and yield responses to amendments to the sugarcane monoculture: towards identifying the reasons behind the response to breaks
Authors: Garside A. L. , Bell M. J.
Published: November 2011

Experiments involving breaks to the sugarcane monoculture, soil fumigation and the application of biocides were conducted in Bundaberg, the Burdekin Valley and at Tully, three sugarcane-growing regions in Queensland, Australia. The aim was to elucidate the cause(s) of previously observed positive yield responses to breaks in the monoculture and assess persistence into a subsequent cane cycle. In all three experiments there was a positive response in the plant cane crop to fumigation of land that was under sugarcane monoculture, the response being 32, 39 and 21% for the Burdekin, Tully and Bundaberg experiments, respectively. Further, at Tully, the response was maintained into the ratoons.
Fumigation after breaks also enhanced yields but the results were variable and were generally less than the response following sugarcane monoculture. At Tully, fumigating after bare fallow, grain crop and pasture breaks enhanced cane yields by 23, 26 and 29%, respectively, while in the Burdekin, responses to fumigation were much smaller at 9% (bare fallow), 4% (grain crop) and 8% (pasture). In Bundaberg, responses ranged from nil following a long-term (70 months) grass pasture up to 35% following a short-term (12 months) grass pasture, with a general trend for the response to fumigation being larger following short-term than long-term breaks.
In the Tully experiment, biocides had variable effects on sugarcane growth and yield. Fungicide application produced as good a yield as fumigation whereas nematicides had little direct influence. However, when combined with fungicides, nematicides provided a synergistic effect in terms of shoot development. The results suggested that at the Tully site, fungi were the major detrimental biota associated with poor yields in long-term sugarcane monoculture, but nematodes had some influence once fungi were controlled.
In two additional experiments at Bundaberg and Burdekin, it was shown that if the cane stool was removed after the plant crop (Bundaberg) and second ratoon (Burdekin) and sugarcane re-planted, there were no residual effects of breaks and fumigation. Thus it appears that the positive effects of breaks and fumigation measured in the ratoons were more associated with the development of a healthy stool in the plant crop than any residual effect on soil biota.
In general the similarly positive response to fumigation and breaks indicated that a considerable part of the overall response to breaks was due to reducing the adverse effect of detrimental soil biota (largely fungi although there was an effect on nematodes). The type and duration of break was also important with long-term pasture being the most effective. However, the duration of the fumigation and break effects on soil biota only lasted for the plant crop.
Advertising sexual health services that provide sexually transmissible infection screening for rural young people - what works and what doesn't
Authors: Gamage Deepa G. , Fuller Candice A. , Cummings Rosey , Tomnay Jane E. , Chung Mark , Chen Marcus , Garrett Cameryn C. , Hocking Jane S. , Bradshaw Catriona S. , Fairley Christopher K.
Published: November 2011

Background ‘TESTme’ is a sexually transmissible infection (STI) screening service for Victorian young people living in rural areas. We evaluated the effectiveness of advertising for this service over an 11-month pilot period. Methods: The advertising that was used included websites, a Facebook page, posters, flyers, business cards, wrist bands and professional development sessions for health nurses that occurred throughout the pilot period. We also used once-off methods including advertisements in newspapers, student diaries and short messages to mobile phones. Results: Twenty-eight clients had a consultation through TESTme. Twenty found the service through health professionals, six through the Melbourne Sexual Health Centre (MSHC) web page, one through the Facebook page and one through the student diary. The total direct costs incurred by the centre for advertising were $20 850. The advertising cost per client reached for each advertising method was $26 for health professionals, $80 for the MSHC web advertisement, $1408 for Facebook and $790 for the student diary. Other advertising methods cost $12 248 and did not attract any clients. Conclusion: Advertising STI health services for rural young people would be best to focus on referrals from other health services or health care websites.
Liver disease, HIV and aging
Authors: Falade-Nwulia Oluwaseun , Thio Chloe L.
Published: November 2011

The life expectancy of HIV-infected patients has increased due to the efficacy of highly active antiretroviral therapy (HAART) in controlling HIV replication; thus, the population living with HIV infection is steadily aging. Liver-related morbidity and mortality has emerged as a leading problem in HIV-infected patients. Since aging, HIV infection and HAART all affect the liver, understanding the impact of the combination of these factors on liver disease is crucial for optimisation of care in the aging HIV-infected population. This review will focus on the current understanding of liver disease in older (>50 years old) HIV-negative individuals and in HIV-infected individuals. Areas for future research in the area of HIV, liver disease and aging will also be discussed.
HIV infection, aging and cardiovascular disease: epidemiology and prevention
Authors: Petoumenos Kathy , Worm Signe W.
Published: November 2011

In the developed world, HIV infection is now well managed with very effective and less toxic antiretroviral treatment. HIV-positive patients therefore are living longer, but are now faced by challenges associated with aging. Several non-AIDS associated morbidities are increased in this population, including cardiovascular disease (CVD). It is suggested that CVD occurs earlier among HIV-positive patients compared with HIV-negative patients, and at a higher rate. Several factors have been proposed to contribute to this. First, the traditional CVD risk factors are highly prevalent in this population. High rates of smoking, dyslipidaemia and a family history of CVD have been reported. This population is also aging, with estimates of more than 25% of HIV-positive patients in the developed world being over the age of 50. Antiretroviral treatment, both through its effect on lipids and through other, sometimes less well understood, mechanisms, has been linked to increased CVD risk. HIV infection, especially untreated, is a further contributing factor to increased CVD risk in HIV-positive patients. As the HIV-positive population continues to age, the risk of CVD will continue to increase. Guidelines for the management and prevention of CVD risk have been developed, and are largely modelled on those used in the general population. However, the data currently suggest that these interventions, such as the use of lipid-lowering medications and smoking cessation programs, remain quite low. A better understanding the mechanisms of CVD risk in this aging population and further efforts in improving uptake of prevention strategies will remain an important research area.
Optimal antiretroviral therapy for aging
Authors: Cordery Damien V. , Cooper David A.
Published: November 2011

The introduction of highly active antiretroviral therapy (HAART) has irrevocably changed the nature of the HIV epidemic in developed countries. Although the use of HAART does not completely restore health in HIV-infected individuals, it has dramatically reduced morbidity and mortality. Increases in life expectancy resulting from effective long-term treatment mean that the proportion of older people living with HIV has increased substantially in the past 15 years. Increasing age is associated with many complications including cardiovascular disease, neurological complications, kidney and liver dysfunction, and metabolic complications such as dyslipidaemia and diabetes. HIV infection and antiretroviral drugs have also been associated with similar complications to those seen with increasing age. The increase in HIV prevalence in older age groups has not been accompanied by the development of treatment guidelines or recommendations for appropriate antiretroviral therapy or clinical management in these patients.
HIV, cancer, and aging
Authors: Grulich Andrew E. , Jin Fengyi , Poynten I. Mary , Vajdic Claire M.
Published: November 2011

As people with HIV age, they will experience increasing rates of all diseases of aging, including cancer. However, the pattern of higher cancer risk in people with HIV is mostly explained by the chronic effects of certain oncogenic infections, and is not consistent with a syndrome of accelerated aging. Many of those cancers that are most closely associated with aging do not occur at increased rates in people with HIV compared with the general population. The risk of many infection-associated cancers in people with HIV is closely related to the degree of immune deficiency, and for some types of cancer, it is also associated with ongoing HIV replication. Thus, if HIV therapy can provide durable HIV suppression and maintain near normal levels of immune function, the excess risk of cancer is likely to be minimised. While avoidance of profound immunity will greatly reduce cancer risk, it is unclear how close to normal immune function must be to minimise HIV-associated cancer risk. People with HIV are also at a high risk of cancer because they have high rates of lifestyle risks for cancer, in particular tobacco and alcohol exposure. For most cancers, it is appropriate to follow general population guidelines on cancer screening. The exception is cervical cancer, for which annual screening is recommended. In addition, active research is required to establish whether anal cancer screening would prevent the unacceptably high levels of morbidity caused by this disease in people with HIV, most particularly in gay men.
The incidence of induced abortion in a prospective cohort study of 16- to 25-year-old Australian women
Authors: Walker Jennifer , McNamee Kathleen , Kaldor John K. , Donovan Basil , Fairley Christopher K. , Pirotta Marie , Bradshaw Catriona S. , Chen Marcus Y. , Garland Suzanne , Hocking Jane S.
Published: November 2011

In Australia, data for induced abortions (IA) is unreliable, although accurate information is essential for the development of policy and funding for services relating to IA. The rate of induced abortion was an incidental finding from questionnaire data collected for a longitudinal study of chlamydia in young women in Australia. We found a pregnancy rate of 7.2/100 woman years (95% confidence interval (CI): 5.7–9.0) (n = 76) and IA rate of 2.1/100 women years (95% CI: 1.4–3.2) (n = 22). Differences were found between States and Territories, information which might influence the development of services in regions of Australia.
Colonic mucosa-associated microbiota is influenced by an interaction of Crohn disease and
FUT2
(
Secretor
) genotype
Authors: Rausch Philipp , Rehman Ateequr , Künzel Sven , Häsler Robert , Ott Stephan J. , Schreiber Stefan , Rosenstiel Philip , Franke Andre , Baines John F.
Published: November 2011

The
FUT2
(
Secretor
) gene is responsible for the presence of ABO histo-blood group antigens on the gastrointestinal mucosa and in bodily secretions. Individuals lacking a functional copy of
FUT2
are known as “nonsecretors” and display an array of differences in susceptibility to infection and disease, including Crohn disease. To determine whether variation in resident microbial communities with respect to
FUT2
genotype is a potential factor contributing to susceptibility, we performed 454-based community profiling of the intestinal microbiota in a panel of healthy subjects and Crohn disease patients and determined their genotype for the primary nonsecretor allele in Caucasian populations,
W143X
(G428A). Consistent with previous studies, we observe significant deviations in the microbial communities of individuals with Crohn disease. Furthermore, the
FUT2
genotype explains substantial differences in community composition, diversity, and structure, and we identified several bacterial species displaying disease-by-genotype associations. These findings indicate that alterations in resident microbial communities may in part explain the variety of host susceptibilities surrounding nonsecretor status and that
FUT2
is an important genetic factor influencing host–microbial diversity.
On homology spheres with few minimal non-faces
Authors: Katthän Lukas
Published: November 2011

Let

Δ
\Delta

be a

(
d
−
1
)

(d-1)

-dimensional homology sphere on

n
n

vertices with

m
m

minimal non-faces. We consider the invariant

α
(
Δ
)
=
m
−
(
n
−
d
)

\alpha (\Delta ) = m - (n-d)

and prove that for a given value of

α
\alpha

, there are only finitely many homology spheres that cannot be obtained through one-point suspension and suspension from another. Moreover, we describe all homology spheres with

α
(
Δ
)

\alpha (\Delta )

up to four and, as a corollary, all homology spheres with up to eight minimal non-faces. To prove these results we consider the lcm-lattice and the nerve of the minimal non-faces of

Δ
\Delta

. Also, we give a short classification of all homology spheres with

n
−
d
≤
3

n-d \leq 3

.
Phosphodiesterase 5 inhibition with sildenafil reverses exercise oscillatory breathing in chronic heart failure: a long‐term cardiopulmonary exercise testing placebo‐controlled study
Authors: Guazzi Marco , Vicenzi Marco , Arena Ross
Published: November 2011

Aims

Exercise oscillatory breathing (EOB) is a ventilatory abnormality that occurs in ∼20% of heart failure (HF) patients and carries a very unfavourable prognosis. Pulmonary vasoconstriction has been suggested to be involved in this disorder. We hypothesized that modulation of pulmonary vascular hypertone by oversignalling of the nitric oxide pathway with phosphodiesterase 5 (PDE5) inhibition might be beneficial. Accordingly, we performed a 1‐year pilot trial with sildenafil in patients with HF and EOB.

Methods and results

Among 122 HF cases, 32 presented with EOB during cardiopulmonary exercise testing (CPX) and were randomized to receive placebo (n = 16) or sildenafil (n = 16) at the dose of 50 mg three times a day, in addition to their current antifailure treatment. CPX‐derived variables and pulmonary haemodynamics were assessed at 6 and 12 months. Sildenafil reversed EOB in 87% of patients at 6 months and 93% at 1 year, respectively (P < 0.01). This effect was accompanied by an improvement in functional performance (peak VO2; from 9.6 to 12.4 and 13.2 mL/min/kg; P < 0.01) and exercise ventilation efficiency (ventilation to CO2 production slope; from 41.1 to 32.7 and 31.5; P < 0.01). Chronic treatment with PDE5 inhibition significantly decreased pulmonary capillary wedge pressure (from 21 to 14 and 14 mmHg), mean pulmonary artery pressure (PAP; from 34.8 to 23 and 24 mmHg), and pulmonary vascular resistance (PVR; from 360 to 270 and 266 dyne/s/cm5) compared with placebo (P < 0.01 for each comparison). On exploratory analysis, there was a correlation between PAP and PVR and the decrease in EOB in the treatment group. Placebo did not alter any of the aforementioned variables.

Conclusions

PDE5 inhibition in HF patients with EOB offers the dual advantage of improving functional capacity and modulating the EOB pattern. PAP and PVR reduction seem to underlie the correction of the breathing disorder. Whether reversal of this unfavourable prognostic signal can affect survival remains unconfirmed at the moment.
Biological Control of Take-All by FluorescentPseudomonasspp. from Chinese Wheat Fields
Authors: Yang Ming-Ming , Mavrodi Dmitri V. , Mavrodi Olga V. , Bonsall Robert F. , Parejko James A. , Paulitz Timothy C. , Thomashow Linda S. , Yang He-Tong , Weller David M. , Guo Jian-Hua
Published: November 2011

Take-all disease of wheat caused by the soilborne fungus Gaeumannomyces graminis var. tritici is one of the most important root diseases of wheat worldwide. Bacteria were isolated from winter wheat from irrigated and rainfed fields in Hebei and Jiangsu provinces in China, respectively. Samples from rhizosphere soil, roots, stems, and leaves were plated onto King's medium B agar and 553 isolates were selected. On the basis of in vitro tests, 105 isolates (19% of the total) inhibited G. graminis var. tritici and all were identified as Pseudomonas spp. by amplified ribosomal DNA restriction analysis. Based on biocontrol assays, 13 strains were selected for further analysis. All of them aggressively colonized the rhizosphere of wheat and suppressed take-all. Of the 13 strains, 3 (HC9-07, HC13-07, and JC14-07, all stem endophytes) had genes for the biosynthesis of phenazine-1-carboxylic acid (PCA) but none had genes for the production of 2,4-diacetylphloroglucinol, pyoluteorin, or pyrrolnitrin. High-pressure liquid chromatography (HPLC) analysis of 2-day-old cultures confirmed that HC9-07, HC13-07, and JC14-07 produced PCA but no other phenazines were detected. HPLC quantitative time-of-flight 2 mass-spectrometry analysis of extracts from roots of spring wheat colonized by HC9-07, HC13-07, or Pseudomonas fluorescens 2-79 demonstrated that all three strains produced PCA in the rhizosphere. Loss of PCA production by strain HC9-07 resulted in a loss of biocontrol activity. Analysis of DNA sequences within the key phenazine biosynthesis gene phzF and of 16S rDNA indicated that strains HC9-07, HC13-07, and JC14-07 were similar to the well-described PCA producer P. fluorescens 2-79. This is the first report of 2-79-like bacteria being isolated from Asia.
Modeling Cold Curing of Pierce's Disease in Vitis vinifera ‘Pinot Noir’ and ‘Cabernet Sauvignon’ Grapevines in California
Authors: Lieth J. H. , Meyer M. M. , Yeo K.-H. , Kirkpatrick B. C.
Published: November 2011

Pierce's disease (PD) of Vitis vinifera grapevines is caused by the bacterium Xylella fastidiosa, a pathogen with a wide plant host range. Exposure of X. fastidiosa-infected plant tissue to cold temperatures has been shown to be effective at eliminating the pathogen from some plant hosts such as grapevines. This “cold curing” phenomenon suggests itself as a potential method for disease management and perhaps control. We investigated cold therapy of PD-affected ‘Pinot Noir’ and ‘Cabernet Sauvignon’ grapevine. In the fall, inoculated plants and controls of each cultivar were transported to each of four field sites in California (Foresthill, McLaughlin, Hopland, and Davis) that differed in the magnitude of cold winter temperatures. A model for progression of the elimination of plant disease in relation to temperature was conceptualized to be a temperature-duration effect, where temperatures below a particular threshold kill X. fastidiosa with increasing efficacy as the temperature decreases to some value <6°C. The temperature effect was modeled as a likelihood of a particular temperature killing the pathogen and is termed the “killing index”. We developed a mathematical model for cold curing of grapevines inoculated with X. fastidiosa and calibrated the model with cold-curing data collected in a field study. Parameter estimation resulted in lowest sum of squared differences across all 10 trials to be low temperature below which the organism is killed (T0) = 6°C, number of hours to achieve 100% cure (N100) = 195 h, number of hours to achieve 10% cure (N10) = 20 h, and killing index (Kx) = 0.45 for Pinot Noir and T0 = 6°C, N100 = 302 h, N10 = 170 h, and Kx = 0.41 for Cabernet Sauvignon. With the parameter estimates optimized by model calibration, the simulation model was effective at predicting cold curing in four locations during the experiment, although there were some differences between Hopland for Pinot Noir and Davis for Cabernet Sauvignon. Using historical temperature data, the model accurately predicted the known severity of PD in other grape-growing regions of California, suggesting that it may have utility in assessing the relative risk of developing PD in proposed new vineyard sites.
Adaptive significance of permanent female mimicry in a bird of prey
Authors: Sternalski Audrey , Mougeot François , Bretagnolle Vincent
Published: November 2011

Permanent female mimicry, in which adult males express a female phenotype, is known only from two bird species. A likely benefit of female mimicry is reduced intrasexual competition, allowing female-like males to access breeding resources while avoiding costly fights with typical territorial males. We tested this hypothesis in a population of marsh harriers
Circus aeruginosus
in which approximately 40 per cent of sexually mature males exhibit a permanent, i.e. lifelong, female plumage phenotype. Using simulated territorial intrusions, we measured aggressive responses of breeding males towards conspecific decoys of females, female-like males and typical males. We show that aggressive responses varied with both the type of decoys and the type of defending male. Typical males were aggressive towards typical male decoys more than they were towards female-like male decoys; female-like male decoys were attacked at a rate similar to that of female decoys. By contrast, female-like males tolerated male decoys (both typical and female-like) and directed their aggression towards female decoys. Thus, agonistic responses were intrasexual in typical males but intersexual in female-like males, indicating that the latter not only look like females but also behave like them when defending breeding resources. When intrasexual aggression is high, permanent female mimicry is arguably adaptive and could be seen as a permanent ‘non-aggression pact’ with other males.
A minute fossil phoretic mite recovered by phase-contrast X-ray computed tomography
Authors: Dunlop Jason A. , Wirth Stefan , Penney David , McNeil Andrew , Bradley Robert S. , Withers Philip J. , Preziosi Richard F.
Published: November 2011

High-resolution phase-contrast X-ray computed tomography (CT) reveals the phoretic deutonymph of a fossil astigmatid mite (Acariformes: Astigmata) attached to a spider's carapace (Araneae: Dysderidae) in Eocene (44–49 Myr ago) Baltic amber. Details of appendages and a sucker plate were resolved, and the resulting three-dimensional model demonstrates the potential of tomography to recover morphological characters of systematic significance from even the tiniest amber inclusions without the need for a synchrotron. Astigmatids have an extremely sparse palaeontological record. We confirm one of the few convincing fossils, potentially the oldest record of Histiostomatidae. At 176 µm long, we believe this to be the smallest arthropod in amber to be CT-scanned as a complete body fossil, extending the boundaries for what can be recovered using this technique. We also demonstrate a minimum age for the evolution of phoretic behaviour among their deutonymphs, an ecological trait used by extant species to disperse into favourable environments. The occurrence of the fossil on a spider is noteworthy, as modern histiostomatids tend to favour other arthropods as carriers.
Population structure in theNeisseria, and the biological significance of fuzzy species
Authors: Corander Jukka , Connor Thomas R. , O'Dwyer Clíona A. , Kroll J. Simon , Hanage William P.
Published: November 2011

Phenotypic and genetic variation in bacteria can take bewilderingly complex forms even within a single genus. One of the most intriguing examples of this is the genusNeisseria, which comprises both pathogens and commensals colonizing a variety of body sites and host species, and causing a range of disease. Complex relatedness among both named species and previously identified lineages ofNeisseriamakes it challenging to study their evolution. Using the largest publicly available collection of bacterial sequence data in combination with a population genetic analysis and experiment, we probe the contribution of inter-species recombination to neisserial population structure, and specifically whether it is more common in some strains than others. We identify hybrid groups of strains containing sequences typical of more than one species. These groups of strains, typical of a fuzzy species, appear to have experienced elevated rates of inter-species recombination estimated by population genetic analysis and further supported by transformation experiments. In particular, strains of the pathogenNeisseria meningitidisin the fuzzy species boundary appear to follow a different lifestyle, which may have considerable biological implications concerning distribution of novel resistance elements and meningococcal vaccine development. Despite the strong evidence for negligible geographical barriers to gene flow within the population, exchange of genetic material still shows directionality among named species in a non-uniform manner.
Operation of the alula as an indicator of gear change in hoverflies
Authors: Walker Simon M. , Thomas Adrian L. R. , Taylor Graham K.
Published: November 2011

The alula is a hinged flap found at the base of the wings of most brachyceran Diptera. The alula accounts for up to 10 per cent of the total wing area in hoverflies (Syrphidae), and its hinged arrangement allows the wings to be swept back over the thorax and abdomen at rest. The alula is actuated via the third axillary sclerite, which is a component of the wing hinge that is involved in wing retraction and control. The third axillary sclerite has also been implicated in the gear change mechanism of flies. This mechanism allows rapid switching between different modes of wing kinematics, by imposing or removing contact with a mechanical stop limiting movement of the wing during the lower half of the downstroke. The alula operates in two distinct states during flight—flipped or flat—and we hypothesize that its state indicates switching between different flight modes. We used high-speed digital video of free-flying hoverflies (Eristalis tenaxandEristalis pertinax) to investigate whether flipping of the alula was associated with changes in wing and body kinematics. We found that alula state was associated with different distributions of multiple wing kinematic parameters, including stroke amplitude, stroke deviation angle, downstroke angle of incidence and timing of supination. Changes in all of these parameters have previously been linked to gear change in flies. Symmetric flipping of the alulae was associated with changes in the symmetric linear acceleration of the body, while asymmetric flipping of the alulae was associated with asymmetric angular acceleration of the body. We conclude that the wings produce less aerodynamic force when the alula is flipped, largely as a result of the accompanying changes in wing kinematics. The alula changes state at mid-downstroke, which is the point at which the gear change mechanism is known to come into effect. This transition is accompanied by changes in the other wing kinematic parameters. We therefore find that the state of the alula is linked to the same parameters as are affected by the gear change mechanism. We conclude that the state of the alula does indeed indicate the operation of different flight modes inEristalis, and infer that a likely mechanism for these changes in flight mode is the gear change mechanism.
John Wallis as editor of Newton's mathematical work
Authors: Guicciardini Niccolò
Published: November 2011

This paper explores Wallis's role as editor of Newton's mathematical work. My objective is to understand how two mathematicians who held different views concerning mathematical method could nonetheless cooperate with one another quite effectively. Most notably, Wallis and Newton pursued different policies as far as the printing of algebra is concerned. In the 1690s Newton held the view that algebra is a heuristic method ‘not worthy of publication’. Wallis, instead, for all his life was keen on making algebraic methods explicit in print. As the analysis of the correspondence between Wallis, Collins and Newton reveals, the methodological tension between Wallis and Newton was resolved in such a way that Newton agreed to print his heuristic methods in Wallis's English
Algebra
(1685) and Latin
Opera
(1693–99). Newton wished to guarantee his priority rights on discoveries in algebra and calculus, yet he also sought to avoid any tight authorial commitment towards them. Wallis, in contrast, received from Newton material that turned out to be useful for the fulfilment of a nationalistic programme aimed at eulogizing British mathematicians as well as his own work.
Arctic plant diversity in the Early Eocene greenhouse
Authors: Harrington Guy J. , Eberle Jaelyn , Le-Page Ben A. , Dawson Mary , Hutchison J. Howard
Published: November 2011

For the majority of the Early Caenozoic, a remarkable expanse of humid, mesothermal to temperate forests spread across Northern Polar regions that now contain specialized plant and animal communities adapted to life in extreme environments. Little is known on the taxonomic diversity of Arctic floras during greenhouse periods of the Caenozoic. We show for the first time that plant richness in the globally warm Early Eocene (approx. 55–52 Myr) in the Canadian High Arctic (76° N) is comparable with that approximately 3500 km further south at mid-latitudes in the US western interior (44–47° N). Arctic Eocene pollen floras are most comparable in richness with today's forests in the southeastern United States, some 5000 km further south of the Arctic. Nearly half of the Eocene, Arctic plant taxa are endemic and the richness of pollen floras implies significant patchiness to the vegetation type and clear regional richness of angiosperms. The reduced latitudinal diversity gradient in Early Eocene North American plant species demonstrates that extreme photoperiod in the Arctic did not limit taxonomic diversity of plants.
Old World monkeys are more similar to humans than New World monkeys when playing a coordination game
Authors: Brosnan Sarah F. , Wilson Bart J. , Beran Michael J.
Published: November 2011

There is much debate about how humans' decision-making compares with that of other primates. One way to explore this is to compare species' performance using identical methodologies in games with strategical interactions. We presented a computerized Assurance Game, which was either functionally simultaneous or sequential, to investigate how humans, rhesus monkeys and capuchin monkeys used information in decision-making. All species coordinated via sequential play on the payoff-dominant Nash equilibrium, indicating that information about the partner's choice improved decisions. Furthermore, some humans and rhesus monkeys found the payoff-dominant Nash equilibrium in the simultaneous game, even when it was the first condition presented. Thus, Old World primates solved the task without any external cues to their partner's choice. Finally, when not explicitly prohibited, humans spontaneously used language to coordinate on the payoff-dominant Nash equilibrium, indicating an alternative mechanism for converting a simultaneous move game into a sequential move game. This phylogenetic distribution implies that no single mechanism drives coordination decisions across the primates, while humans' ability to spontaneously use language to change the structure of the game emphasizes that multiple mechanisms may be used even within the same species. These results provide insight into the evolution of decision-making strategies across the primates.