bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen and methane depletion in soil affected by leakage of natural gas
Authors: Steven M. D. , Smith K. L. , Beardsley M. D. , Colls J. J.
Published: November 2006

As part of a study to simulate plant responses to leaks from pipelines, we injected natural gas into soil at a depth of 1 m in plots of grass, wheat and beans. Measurements of oxygen and methane in soil exposed to gas show that oxygen is depleted significantly to values less than would be caused by simple displacement by natural gas, indicating consumption within the soil by methanotrophic bacteria. Gas concentrations were clustered into two groups: 18% of the oxygen values were less than 1% by volume and 52% of the methane values were less than 5% by volume, indicating a tendency towards either oxygen‐limiting or methane‐limiting conditions. Oxygen depletion was significantly greater in summer. Depletion rates were greatest under grass, and least under wheat. In grass, 36% of the variation in depletion is explained by soil temperature at 10 cm with Q10 = 2.0 over the 0–20°C range. We developed a model that accounts for three gas exchange mechanisms: soil‐air displacement by the injected gas; gas consumption by bacteria; and re‐infusion of the soil atmosphere to account for a net loss of gas volume by consumption. Using this model, we calculate that an average of 37% of the methane was consumed. At initial methane concentrations less than 10% by volume, as much as 100% of the gas was consumed, but consumption efficiency decreased rapidly thereafter. These findings indicate that the soil sink for methane is dynamic and adaptive, acting as a significant constraint on underground methane sources, limited primarily by oxygen availability.
Yield response of crops amended with sewage sludge in the field is more affected by sludge properties than by final soil metal concentration
Authors: De Brouwere K. , Smolders E.
Published: November 2006

Adverse effects on crop yield or quality have been reported in sewage‐sludge treated soils at soil total metal concentrations below those of the current EU directives. A field trial was set up in Belgium (2002–2004) to assess crop response to the application of sewage sludge below these soil thresholds but with sludge metal concentrations either above (high‐metal) or below (low‐metal) sludge metal limits. Two lime‐stabilized and two raw, dewatered sludges were applied annually at rates of 10, 25 and 50 t dry matter (dm) ha−1 for 3 years with four rates of N‐fertilizer as a reference. Final soil metal concentrations increased to maximums of 1.6 mg Cd kg−1 and 225 mg Zn kg−1 through sludge applications. Maize yield was marginally affected by treatments in year 1, whereas wheat and barley grain yields in subsequent years increased up to threefold with increasing sludge or fertilizer rates and were mainly explained by grain‐N. However, the grain yield of winter wheat in year 2 was reduced by about 14% in lime‐stabilized high‐metal sludge treatments compared with wheat receiving N‐fertilizer at equivalent grain‐N. Wheat grain and straw analysis showed no nutrient deficiencies but Zn concentrations in grain and straw were greater than in N‐fertilizer and lime‐stabilized, low‐metal sludge treatments, suggesting Zn toxicity. Sludge properties other than Cd concentration (e.g. electrical conductivity) affected crop Cd in the first year (maize), whereas significant correlations between Cd application and wheat grain Cd were found in the second year. Wheat grain Cd concentrations reached the international trade guideline of 0.1 mg Cd kg−1 fresh weight in the plots amended with lime‐treated, high‐metal sludge even though soil Cd remained below EU limits. In the third year, barley grain Cd remained largely below EU limits. We discuss the possibility that sludge properties rather than soil total metal concentrations are related to effects on crops in the initial years after sludge applications. In none of the 3 years were any adverse effects on crops found for sludge meeting current EU regulations.
Suppression of major histocompatibility complex class II‐associated invariant chain enhances the potency of an HIV gp120 DNA vaccine
Authors: Lu Xueqing , Wu Shuzhen , Blackwell Catherine E. , Humphreys Robert E. , Von Hofe Eric , Xu Minzhen
Published: November 2006

One function of the major histocompatibility complex (MHC) class II‐associated invariant chain (Ii) is to prevent MHC class II molecules from binding endogenously generated antigenic epitopes. Ii inhibition leads to MHC class II presentation of endogenous antigens by APC without interrupting MHC class I presentation. We present data that in vivo immunization of BALB/c mice with HIV gp120 cDNA plus an Ii suppressive construct significantly enhances the activation of both gp120‐specific T helper (Th) cells and cytotoxic T lymphocytes (CTL). Our results support the concept that MHC class II‐positive/Ii‐negative (class II+/Ii–) antigen‐presenting cells (APC) present endogenously synthesized vaccine antigens simultaneously by MHC class II and class I molecules, activating both CD4+ and CD8+ T cells. Activated CD4+ T cells locally strengthen the response of CD8+ CTL, thus enhancing the potency of a DNA vaccine.
Differential type I interferon activation and susceptibility of dendritic cell populations to porcine arterivirus
Authors: Loving Crystal L. , Brockmeier Susan L. , Sacco Randy E.
Published: November 2006

Dendritic cells (DCs) play a role in anti‐viral immunity by providing early innate protection against viral replication and by presenting antigen to T cells for initiation of the adaptive immune response. Studies show the adaptive response to porcine reproductive and respiratory syndrome virus (PRRSV) is ineffective for complete viral elimination. Other studies describe the kinetics of the adaptive response to PRRSV, but have not investigated the early response by DCs. We hypothesize that there is an aberrant activation of DCs early in PRRSV infection; consequently, the adaptive response is triggered inadequately. The current study characterized a subtype of porcine lung DCs (L‐DCs) and investigated the ability of PRRSV to infect and replicate in L‐DCs and monocyte‐derived DCs (MDDCs). Furthermore, the type I interferon anti‐viral response to PRRSV with and without the addition of recombinant porcine IFN‐α (rpIFN‐α), an important cytokine that signals for anti‐viral mediator activation, was analysed. Results show that PRRSV replicated in MDDCs but not L‐DCs, providing evidence that these cells have followed distinct differentiation pathways. Although both cell types responded to PRRSV with an induction of IFN‐β mRNA, the magnitude and duration of the response differed between cell types. The addition of rpIFN‐α was protective in MDDCs, and mRNA synthesis of Mx (myxovirus resistant) and PKR (double‐stranded RNA dependent protein kinase) was observed in both cell types after rpIFN‐α addition. Overall, PRRSV replicated in MDDCs but not L‐DCs, and rpIFN‐α was required for the transcription of protective anti‐viral mediators. DC response to PRRSV was limited to IFN‐β transcription, which may be inadequate in triggering the adaptive immune response.
MEKK3 is essential for lipopolysaccharide‐induced interleukin‐6 and granulocyte–macrophage colony‐stimulating factor production in macrophages
Authors: Kim Kihwan , Duramad Omar , Qin Xiao‐Feng , Su Bing
Published: November 2006

Mitogen‐activated protein/ERK kinase kinase 3 (MEKK3) is a Ser/Thr protein kinase belonging to the MEKK/STE11 subgroup of the MAP3K family. Recently, we found that MEKK3 plays a critical role in interleukin‐1 (IL‐1) receptor and Toll‐like receptor 4 signalling using established primary mouse embryonic fibroblast (MEF) cell lines. However, the function of MEKK3 in immune cells has not been studied because germ‐line MEKK3 knockout mice are embryonically lethal between embryonic days 10 and 11. In this study, we used small interference RNA to the mouse Mekk3 gene to specifically knock down MEKK3 expression in the macrophage line Raw264.7. We found that the lipopolysaccharide‐induced IL‐6 and granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) production was dramatically decreased in MEKK3 knockdown cells whereas the tumour necrosis factor‐α and IL‐1β production were not affected. We also observed that the ERK1/2, p38 and JNK MAPK induction in MEKK3 knockdown cells were moderately inhibited within the first 60 min of stimulation, while the ERK and p38 were more severely inhibited after 2–4 hr of stimulation. Degradation of IκBα was also partially blocked in MEKK3 knockdown cells. Notably, the impairment in IL‐6 and GM‐CSF production in the MEKK3 knockdown cells was restored by reintroducing a human Mekk3 cDNA that could not be targeted by mouse Mekk3‐siRNAs. In conclusion, this study showed that MEKK3 is a crucial and specific regulator of the proinflammatory cytokines IL‐6 and GM‐CSF in macrophages and provided a novel method for investigating MEKK3 function in other immune cells.
Does supplementary prenatal nursing and home visitation reduce healthcare costs in the year after childbirth?
Authors: Au Flora , Shiell Alan , Van Der Pol Marjon , Johnston David W. , Tough Suzanne
Published: November 2006

Aim. This paper reports the costs of a programme of supplementary prenatal care, including healthcare costs, in the year following childbirth.

Background. Publicly funded healthcare systems have provided pregnant women with adequate medical care, but access to resources to address their non‐medical needs is still an issue. To improve women's access to pregnancy‐related resources, a community‐based, prenatal programme involving consultations with a specialist nurse, or nurse plus a home visitor was evaluated.

Method. A sample of 284 women who had participated in a randomized controlled trial of the prenatal care programme participated in this partial economic analysis. Women had been randomized to one of three trial arms: (1) standard care, (2) standard care plus consultations with a specialist prenatal care nurse, or (3) standard care plus nurse consultations and a home visitor. For the economic study, each woman was asked about her and her baby's use of healthcare services in the 12 months after the baby's birth. Health service utilization was multiplied by the unit cost of each service and summed to arrive at the total cost of services used. The study was undertaken in 2004.

Results. Supplementary prenatal care neither increased the use of health services nor resulted in savings in health spending. Compared with standard care, women in the two intervention groups made more use of family physicians and less use of paediatricians, but no significant differences in the overall costs of health care were noted.

Conclusion. While supplementary prenatal care had no impact on costs, some benefits occurred for those at greatest risk of not accessing services. However, it would be premature to draw widespread recommendations for policy from the results of a single study. Further investment in prenatal care should continue to be accompanied by rigorous evaluation of its costs and the value that women place on the service provided.
Disentangling the effects of psychological and physical work demands on sleep, recovery and maladaptive chronic stress outcomes within a large sample of Australian nurses
Authors: Winwood Peter C. , Lushington Kurt
Published: November 2006

Aim.  This paper reports a study to determine if different types of work strain experienced by nurses, particularly those of an essentially psychological nature, such as emotional demand, mental effort and problems with peers and/or supervisors, have a differential impact on sleep quality and overall recovery from work strain, compared with physical work strains, and lead to higher maladaptive chronic fatigue outcomes.

Background.  Various studies have shown that the dominant work‐demand strain associated with nursing work can vary between different areas of nursing. For example, whereas emotional strain is reported to be the principal strain associated with work in areas such as oncology, haematology and renal units, medical and surgical unit nurses report work pace and staffing issues as the dominant work strain. Purely physical strain seems to be less commonly reported as a concern.

Method.  A large sample (n = 760) of Australian nurses working in a large metropolitan hospital completed questionnaires on their work demands, sleep quality, fatigue, and recovery between shifts in January 2004.

Findings.  A high work pace exacerbates the psychological rather than the physical strain demands of nursing. Psychological strain affects sleep quality and impairs recovery from overall work strain between shifts. This combination is highly predictive of serious maladaptive stress/fatigue outcomes among nurses.

Conclusion.  Coping with psychological stressors adequately is an important requirement for nurses in order to avoid adverse health effects and maintain a long‐term career in nursing. Appropriate training of undergraduate nursing students in managing the stresses they are likely to encounter would seem to be an essential requirement for the 21st century. Such training might constitute an important long‐term component in overcoming the chronic nurse shortages evident in many countries.
Organizational predicaments: ethical conditions for nursing research
Authors: Toffoli Luisa , Rudge Trudy
Published: November 2006

Aim.  This paper highlights the sometimes problematic matter of access to the field in clinical ethnographic research by discussing a hypothetical scenario of an instance of change in the terms of access.

Background.  A review of the methodological literature about research access revealed that there was little in the nursing literature about this issue, although anecdotally many nurse researchers reveal that access is not unproblematic and requires active maintenance to ensure smooth operation of a project. However, in returning to literature in sociology and anthropology, where gaining access for fieldwork is not considered so routine, we found much in the literature about dilemmas, predicaments and conflicts over access, confidentiality and anonymity that were not mentioned in nursing research about access to clinical areas. We returned also to the ethical and legal framework guiding access practices so as to explore the issues in fieldwork situations.

Discussion.  In exploring the problems arising from maintaining confidentiality, safety of participants and researchers, it is clear that the much‐vaunted insider status is both a boon and a burden. Intimate and inquisitive research using ethnographic techniques has the potential to unsettle organizations and workers through the very processes used to undertake the research.

Conclusion.  Ethical comportment is not enough to protect a study. A more overt and less naïve approach to access for fieldwork is required to better inform future nurse researchers how to maintain access to the field and the requirement of constant negotiation and adjustment.
Impact of recurrent changes in the work environment on nurses’ psychological well‐being and sickness absence
Authors: Verhaeghe Rik , Vlerick Peter , Gemmel Paul , Maele Georges Van , Backer Guy De
Published: November 2006

Aim.  This paper is a report of a study of how the occurrence and appraisal of recurrent changes in the work environment of hospital nurses affect psychological well‐being (i.e. job satisfaction, eustress and distress) and absence through illness.

Background.  Many researchers have demonstrated the impact of major organizational changes on employees’ psychological well‐being, but only a few have focused on the permanent consequences in work conditions. In a contemporary healthcare setting, an increased number of recurrent operational changes has become a normal characteristic of nurses’ work environment. Specific work situations have frequently been associated with occupational stress, whereas employees’ appraisal of recurrent changes as stressors and their relation to psychological well‐being and health outcomes (i.e. sickness absence) have been dismissed.

Methods.  A cross‐sectional questionnaire survey was conducted in 2003 with 2094 Registered Nurses in 10 general hospitals. Logistic regressions were used to investigate the impact on psychological well‐being and prospectively measured rates of sickness absence (frequency and duration).

Results.  The occurrence of changes in the work environment (in the past 6 months) had had a negative impact on staff psychological well‐being. Nurses who had been confronted with changes scored statistically significantly higher for distress. Changes appraised as threatening were negatively related to job satisfaction and eustress, and positively related to distress and sickness absence (frequency and duration). Changes appraised as challenging were positively related to job satisfaction and eustress but had no impact on distress and sickness absence.

Conclusion.  Future research should take into consideration the impact of the occurrence and appraisal of recurrent changes in the work environment of healthcare employees (i.e. Registered Nurses) on psychological well‐being and sickness absence. This should also be considered by managers when dealing with these nursing workforce issues.
Women's perceptions of partner support and conflict in the development of postpartum depressive symptoms
Authors: Dennis Cindy‐Lee , Ross Lori
Published: November 2006

Aim.  This paper reports a study examining the influence of maternal perceptions of conflict and relationship‐ and postpartum‐specific support from the partner on the development of depressive symptoms in the first 8‐weeks postpartum.

Background.  Although the quality of a woman's relationship with her partner has been associated with risk for postpartum depression, few studies have examined which elements of partner‐specific support and conflict are determinants of maternal mental health.

Methods.  Self‐administered measures of partner support (Social Provisions Checklist, Postpartum Partner Support Scale), partner conflict (Quality of Relationships Inventory), and depression (Edinburgh Postnatal Depression Scale) were mailed postnatally to a population‐based sample of 396 mothers between April 2001 to January 2002. Differences in partner support and conflict at 1 and 4‐weeks postpartum were examined between those women who met criteria for probable depression (Edinburgh Postnatal Depression Scale > 9) and those who did not meet criteria for probable depression at 8‐weeks postpartum.

Findings.  Women with depressive symptoms at 8‐weeks postpartum had significantly lower perceptions of relationship‐specific and postpartum‐specific partner support and significantly higher levels of relationship conflict than women with no depressive symptoms. Multiple regression analyses revealed that three variables, perceived social integration, partner encouragement to obtain help when needed, and partner agreed with infant care, significantly explained the variance in Edinburgh Postnatal Depression Scale scores.

Conclusions.  Maternal perceptions of social integration and partner provision of problem‐focused informational support and positive feedback are important in determining maternal mental health. Therefore, in the antenatal period healthcare professionals should teach couples appropriate ways to provide feedback and communicate expectations, especially those relating to infant care strategies. The importance of appraisal and emotional support should be highlighted in order to foster maternal feelings of acceptance and being cared for. Partners should also be encouraged to participate actively in household tasks and infant care activities to protect the mother from becoming overwhelmed.
Patterns in the assembly of an island plant community
Authors: Burns K. C.
Published: November 2006

Aim  To test for patterns in the assembly of an island plant community.

Location  Islands off the west coast of Vancouver Island, British Columbia, Canada.

Methods  Twenty‐seven islands were visited by boat, and the abundance of six woody angiosperm species was quantified. Null models were then used to test whether: (1) some species co‐occur less than expected by chance (i.e. co‐occurrence assembly rule), (2) the incidence and abundance of some species are inversely related to the abundance of other species (i.e. incidence assembly rule), and (3) support for assembly rules precludes evidence for nestedness, which refers to a pattern in species composition in which the species present on depauperate islands form regular subsets of those occurring on progressively more diverse islands.

Results  Most species co‐occurred with other species at frequencies expected by chance. However, one species (Sambucus racemosa) co‐occurred with other species less frequently than randomized expectations. The observed incidence and abundance patterns of most species were also consistent with randomized patterns. However, the incidence and abundance of S. racemosa declined with the abundance of other plant species. Weak, variable support was found for nestedness of the total plant community. However, stronger, consistent support was found after removing S. racemosa from the matrix prior to analyses.

Main conclusions  Most species were assembled on islands in a manner consistent with randomized expectations. However, non‐random distributional patterns were observed in one species whose distribution was consistent with the hypothesis that competition limits the assembly of island communities.
Ecology and biogeography of plant communities associated with the post Plio‐Pleistocene relictRhododendron ponticumsubsp.baeticumin southern Spain
Authors: Mejías José A. , Arroyo Juan , Marañón Teodoro
Published: November 2006

Aims Rhododendron ponticumL. is reputed to be a post Plio‐Pleistocene relict plant species with a disjunct distribution that comprises the Iberian Peninsula to the west and the Euxinian region plus some restricted Mediterranean areas to the east. We analysed the ecological range (of subsp.baeticum) in the western area (Aljibe Mountains, north of the Strait of Gibraltar) to understand the factors determining the present area limitation.

Location Sierra del Aljibe, north of the Strait of Gibraltar (Iberian Peninsula).

Methods We selected 20 riparian sites whereR. ponticumis common, and compiled data on the ecological diversity of associated woody species and ferns. We established a 500‐m main transect in each site, along the stream or river course, in which we placed five 20‐m‐long plots at regular intervals. We recorded physiographic habitat features, woody plants and fern abundance, and the number ofR. ponticumindividuals.

Results Rhododendron ponticumin southern Spain is restricted to riparian forests in acidic soils (pH 4.0–6.4), and is mainly found on the banks of inclined and enclosed streams. In our inventory we recorded 59 woody taxa and 12 ferns, withR. ponticumbeing the dominant species of the understorey (mean abundance 78.6%). The communities are characterized by a high incidence of the humid warm temperate element, both in number of species (18.8 ± 3.7 per site) and abundance; meanwhile, the presence of the modern Mediterranean element (mean number of species 3.4 ± 3.8 per site) appears to be favoured by disturbance. These ecological–historical groups of taxa also show distinct patterns of typological habit, frequency of endemism, infrageneric diversity and geographical range. Populations ofR. ponticumare characterized by a very variable density of seedlings in many sites, and the virtual lack of juveniles.

Main conclusions Riparian forests of the Aljibe Mountains constitute a refuge forR. ponticumwhere the species persists, but populations appear to be in decline. The narrow ecological range ofR. ponticumin the area strongly contrasts with its wide amplitude in the eastern natural area, mainly the Euxinian region, whereR. ponticumprobably finds better conditions due to the environmental heterogeneity of the region, and the lack of a hot dry season.
An analysis of the stressors and coping strategies of Chinese adults with a partner admitted to an intensive care unit in Hong Kong: an exploratory study
Authors: Chan Keung‐Sum , Twinn Sheila
Published: November 2006

Aims.  The aim of this study was to identify the major stressors affecting Chinese adults whose partner had been admitted to an intensive care unit and to understand the major coping strategies employed to manage such stressors.

Background.  Recently a greater number of patients of higher acuity have been admitted to intensive care units and survive lengthy illnesses of an unpredictable course. Such critical illnesses have been identified as a major life event to family members of these patients. Little is known, however, about the stressors and coping mechanisms of Chinese adults whose critically ill partner is admitted to an intensive care unit.

Methods.  An exploratory qualitative design was selected to achieve the aims of the study. A purposive sample of 10 Chinese adults with a partner in an intensive care unit of a regional general hospital in Hong Kong participated in tape‐recorded semi‐structured interviews. Content analysis was employed to analyse the translated interviews.

Findings.  Categories of stressors included uncertainty, difficulties in communication, changes in roles and responsibilities, difficulties in decision making, financial strain as well as changes in relationships. Analysis identified a range of coping strategies which included seeking information, seeking support, reliance on cultural beliefs and practices, turning to religious beliefs, maintaining hope and acceptance of illness.

Conclusions.  The findings demonstrate the importance of cultural beliefs and practices in determining the coping mechanisms employed to manage the stressors identified by this sample of Chinese adults. Such findings indicate the use of both internal and external coping strategies in order to maintain equilibrium in the family.

Relevance to clinical practice.  Implications for nursing practice highlight the significance of seeking information throughout the critical period and also culturally appropriate support from healthcare professionals.
Review of effective advanced cardiac life support training using experiential learning
Authors: Kidd Tracy , Kendall Sharon
Published: November 2006

Aims and objectives. This paper examines issues of contention regarding current practices and suggests the application of the experiential theory of learning (incorporating reflective practice) to advanced cardiac life support (ACLS) training.

Background. The need for formalized training in cardiopulmonary resuscitation (CPR) and ACLS is well documented. However, the effectiveness of traditional training programmes has not been firmly established. The question still remains – how to best ensure transfer of learning enabling learners to apply classroom knowledge successfully in the clinical setting. It is argued that educators can no longer rely on traditional teaching methods and more effective learner‐centred education techniques are required.

Method. A review of available literature regarding ACLS training has been conducted for this discussion. Data sources and selection: MEDLINE, CINAHL, OVID, Expanded Academic and Proquest were searched using textwords. English‐language articles related to CPR and ACLS practices and also experiential learning were reviewed. Additional references were also reviewed from the bibliographies and from citation searches on key articles. Articles related to CPR/ACLS and experiential learning practices published within the last 10 years were reviewed.

Results. There is evidence that past ACLS training programmes have proven inconsistent and inadequate, with numerous studies reporting trainees have poor retention; and, therefore, ineffective ACLS skills as a result.

Conclusions. The reviewed literature demonstrates that the need for effective ACLS training is clear. Increasing numbers of critically ill patients in hospitals means that it has never been more important to ensure the competence of healthcare professionals. Training must give learners a chance to pull together all aspects of ACLS and the use of experiential learning has the potential to achieve this aim.

Relevance to clinical practice. It is argued that providing training designed and implemented using experimental learning enhances learning through critical thinking and reflection, and subsequently should improve ACLS outcomes.
A systematic review of predictors and screening instruments to identify older hospitalized patients at risk for functional decline
Authors: Hoogerduijn Jita G , Schuurmans Marieke J , Duijnstee Mia SH , De Rooij Sophia E , Grypdonck Mieke FH
Published: November 2006

Aims and objectives. To determine a valid, reliable and clinical user‐friendly instrument, based on predictors of functional decline, to identify older patients at risk for functional decline. The predictors of functional decline are initially considered and, subsequently, the characteristics and psychometric qualities of existing screening instruments are investigated.

Background. Functional decline is a common and serious problem in older hospitalized patients, resulting in a change in quality of life and lifestyle. Studies have shown that 30–60% of older people develop new dependencies in activities of daily living (ADL) during their hospital stay. Adverse health outcomes such as mortality, a prolonged hospital stay, nursing home placement and increased dependency of older people at home are the results. Not only are the personal costs high but also, in a rapidly growing older population, the impact on health‐care costs is also high.

Results. Age, lower functional status, cognitive impairment, preadmission disability in instrumental activities of daily life (IADL), depression and length of hospital stay were identified as predictors of functional decline. Three screening instruments to identify hospitalized patients at risk for functional decline were found in the literature: the Hospital Admission Risk Profile, the Identification of Seniors at Risk and the Care Complexity Prediction Instrument. The reported validity was moderate. Reliability and the ease of use in the clinical setting were not well described.

Conclusion. These three instruments should be further tested in a hospitalized older population.

Relevance to clinical practice. Screening is a first step to identify patients at risk for functional decline and this will make it possible to treat patients who are identified so as to prevent functional decline. Because of their ability to observe and to guide the patients and the overall view they have, nurses play a key role in this process.
In vitro replication models for the hepatitis C virus
Authors: Sheehy P. , Mullan B. , Moreau I. , Kenny‐Walsh E. , Shanahan F. , Scallan M. , Fanning L. J.
Published: November 2006

Summary.  Soon after the discovery of the hepatitis C virus (HCV), attention turned to the development of models whereby replication of the virus could be investigated. Among the HCV replication models developed, the HCV RNA replicon model and the newly discovered infectious cell culture systems have had an immediate impact on the study of HCV replication, and will continue to lead to important advances in our understanding of HCV replication. The aim of this study is to deal with developments in HCV replication models in a chronological order from the early 1990s to the recent infectious HCV cell culture systems.
Epidemiological characteristics and response to peginterferon plus ribavirin treatment of hepatitis C virus genotype 4 infection
Authors: Roulot D. , Bourcier V. , Grando V. , Deny P. , Baazia Y. , Fontaine H. , Bailly F. , Castera L. , De Ledinghen V. , Marcellin P. , Poupon R. , Bourlière M. , Zarski J. P. , Roudot‐Thoraval F. ,   The Observational VHC4 Study Group
Published: November 2006

Summary.  Hepatitis C virus genotype 4 (HCV‐4) infection is progressing in Europe, where epidemiology and sustained virological response (SVR) seem to be different than in the Middle East. We analysed epidemiological features and SVR rates in a retrospective study of 1532 HCV‐4‐infected patients, including 1056 patients infected in France, 227 immigrants infected in Egypt and 249 in sub‐Saharan Africa. SVR rates were assessed in 242 naive patients of the 1532, who received peginterferon plus ribavirin for 48 weeks. HCV subtype 4a or 4d was the most common among patients infected in France, where the predominant route of transmission was intravenous drug abuse. The 4a subtype was largely predominant (93%) among patients infected in Egypt, where transmission was mostly because of parenteral treatment for schistosomiasis. More than seven different subtypes and no predominant route of infection were found in patients infected in sub‐Saharan Africa. Liver fibrosis was significantly less severe in patients infected in France and Africa than in patients infected in Egypt. SVR rates were higher in patients infected in Egypt, compared with those infected in France or Africa (54.9%, 40.3% and 32.4%, respectively, P < 0.05). An overall better response was observed in patients infected with the 4a subtype. In multivariate analysis, two factors were associated independently with SVR: the Egyptian origin of transmission and the absence of severe fibrosis. In conclusion, the distribution of HCV‐4 subtypes varies with the geographical origin of transmission and affects the SVR following antiviral treatment.
Fine‐scale spatial genetic structure and dispersal among spotted salamander (Ambystoma maculatum) breeding populations
Authors: ZAMUDIO KELLY R. , WIECZOREK ANIA M.
Published: November 2006

We examined fine‐scale genetic variation among breeding aggregations of the spotted salamander (Ambystoma maculatum) to quantify dispersal, interpopulation connectivity and population genetic structure. Spotted salamanders rely on temporary ponds or wetlands for aggregate breeding. Adequate breeding sites are relatively isolated from one another and field studies suggest considerable adult site fidelity; therefore, we expected to find population structure and differentiation at small spatial scales. We used microsatellites to estimate population structure and dispersal among 29 breeding aggregations in Tompkins County, New York, USA, an area encompassing 1272 km2. Bayesian and frequency‐based analyses revealed fine‐scale genetic structure with two genetically defined demes: the North deme included seven breeding ponds, and the South deme included 13 ponds. Nine ponds showed evidence of admixture between these two genetic pools. Bayesian assignment tests for detection of interpopulation dispersal indicate that immigration among ponds is common within demes, and that certain populations serve as sources of immigrants to neighbouring ponds. Likewise, spatial genetic correlation analyses showed that populations ≤ 4.8 km distant from each other show significant genetic correlation that is not evident at higher scales. Within‐population levels of relatedness are consistently larger than expected if mating were completely random across ponds, and in the case of a few ponds, within‐population processes such as inbreeding or reproductive skew contribute significantly to differentiation from neighbouring ponds. Our data underscore the importance of these within‐population processes as a source of genetic diversity across the landscape, despite considerable population connectivity. Our data further suggest that spotted salamander breeding groups behave as metapopulations, with population clusters as functional units, but sufficient migration among demes to allow for potential rescue and recolonization. Amphibian habitats are becoming increasingly fragmented and a clear understanding of dispersal and patterns of population connectivity for taxa with different ecologies and life histories is crucial for their conservation.
Genetic analysis reveals population structure and recent migration within the highly fragmented range of the Cross River gorilla (Gorilla gorilla diehli)
Authors: BERGL RICHARD A. , VIGILANT LINDA
Published: November 2006

Recently developed methods of individual‐based analysis of genetic data allow an unprecedented opportunity to understand the relationships among fragmented populations. By defining population structure and identifying migrant individuals, such analyses can provide a framework to aid in evaluating the threats posed by inbreeding and reduced genetic variability as a consequence of limited gene flow among fragments. Here we investigate population structure in the critically endangered Cross River gorilla (Gorilla gorilla diehli) by applying a suite of individual‐based analyses to data obtained from between one‐quarter and one‐third of the estimated total population through the use of noninvasively collected DNA samples. The population structure inferred using data from 11 autosomal microsatellite loci was broadly consistent with geography and habitat fragmentation, but showed no simple isolation‐by‐distance effects. In contrast to previous field surveys, which suggested that all gorilla localities were isolated from one another, we infer low levels of gene flow and identify migrants between habitat fragments as well as individuals of admixed ancestry, suggesting persistent recent reproductive contact between many of the localities. These results are encouraging for the conservation of the Cross River gorilla population. Conservation efforts should strive to maintain connectivity between subpopulations that are still in migratory contact and attempt to restore connectivity where it has been lost.
Hybridization between white‐headed ducks and introduced ruddy ducks in Spain
Authors: MUÑOZ‐FUENTES V. , VILÀ C. , GREEN A. J. , NEGRO J. J. , SORENSON M. D.
Published: November 2006

The ruddy duck, Oxyura jamaicensis, was introduced to Great Britain in the mid‐20th century and has recently spread to other Western European countries. In Spain, ruddy ducks hybridize with the globally endangered white‐headed duck, Oxyura leucocephala. We assessed the effects of hybridization on the Spanish white‐headed ducks, which constitute 25% of the global population of this species, using a panel of eight nuclear intron markers, 10 microsatellite loci, and mtDNA control region sequences. These data allowed parental individuals, F1 hybrids, and the progeny of backcrossing to be reliably distinguished. We show that hybrids between the two species are fertile and produce viable offspring in backcrosses with both parental species. To date, however, we found no extensive introgression of ruddy duck genes into the Spanish white‐headed duck population, probably due to the early implementation of an effective ruddy duck and hybrid control programme. We also show that genetic diversity in the expanding European ruddy duck population, which was founded by just seven individuals, exceeds that of the native Spanish white‐headed duck population, which recently recovered from a severe bottleneck. Unless effective control of ruddy ducks is continued, genetic introgression will compromise the unique behavioural and ecological adaptations of white‐headed ducks and consequently their survival as a genetically and evolutionary distinct species.
Tectono‐sedimentary evolution of lower to middle Miocene half‐graben basins related to an extensional detachment fault (western Crete, Greece)
Authors: Seidel Markus , Seidel Eberhard , Stöckhert Bernhard
Published: November 2006

Crustal extension in the overriding plate at the Aegean subduction zone, related to the rollback of the subducting African slab in the Miocene, resulted in a detachment fault separating high‐pressure/low‐temperature (HP‐LT) metamorphic lower from non‐metamorphic upper tectonic units on Crete. In western Crete, detachment faulting at deeper crustal levels was accompanied by structural disintegration of the hangingwall leading to the formation of half‐graben‐type sedimentary basins filled by alluvial fan and fan‐delta deposits. The coarse‐grained clastic sediments in these half‐grabens are exclusively derived from the non‐metamorphic units atop the detachment fault. Being in direct tectonic contact with HP‐LT metamorphic rocks of the lower tectonic units today, the basins must have formed in the period between c. 20 and 15 Ma, prior to the exposure of the HP‐LT metamorphic rocks at the surface, and juxtaposed with the latter during ongoing deformation.
A CDPK isoform participates in the regulation of nodule number inMedicago truncatula
Authors: Gargantini Pablo R. , Gonzalez‐Rizzo Silvina , Chinchilla Delphine , Raices Marcela , Giammaria Verónica , Ulloa Rita M. , Frugier Florian , Crespi Martin D.
Published: November 2006

Medicagospp. are able to develop root nodules via symbiotic interaction withSinorhizobium meliloti. Calcium‐dependent protein kinases (CDPKs) are involved in various signalling pathways in plants, and we found that expression ofMtCPK3, a CDPK isoform present in roots of the model legumeMedicago truncatula, is regulated during the nodulation process. Early inductions were detected 15 min and 3–4 days post‐inoculation (dpi). The very early induction ofCPK3messengers was also present in inoculatedM. truncatuladmimutants and in wild‐type roots subjected to salt stress, indicating that this rapid response is probably stress‐related. In contrast, the later response was concomitant with cortical cell division and the formation of nodule primordia, and was not observed in wild‐type roots inoculated withnod −strains. This late induction correlated with a change in the subcellular distribution of CDPK activities. Accordingly, an anti‐MtCPK3 antibody detected two bands in soluble root extracts and one in the particulate fraction. CPK3::GFP fusions are targeted to the plasma membrane in epidermal onion cells, a localization that depends on myristoylation and palmitoylation sites of the protein, suggesting a dual subcellular localization.MtCPK3mRNA and protein were also up‐regulated by cytokinin treatment, a hormone linked to the regulation of cortical cell division and other nodulation‐related responses. An RNAi‐CDPK construction was used to silence CPK3 inAgrobacterium rhizogenes‐transformed roots. Although no major phenotype was detected in these roots, when infected with rhizobia, the total number of nodules was, on average, twofold higher than in controls. This correlates with the lack ofMtCPK3induction in the inoculated super‐nodulatorsunnmutant. Our results suggest that CPK3 participates in the regulation of the symbiotic interaction.
Genomic‐assisted identification of genes involved in secondary growth in Arabidopsis utilising transcript profiling of poplar wood‐forming tissues
Authors: Ubeda‐Tomas Susana , Edvardsson Ellinor , Eland Cathlene , Singh Sunil Kumar , Zadik Daniel , Aspeborg Henrik , Gorzsàs Andràs , Teeri Tuula T. , Sundberg Björn , Persson Per , Bennett Malcolm , Marchant Alan
Published: November 2006

Despite the importance of secondary growth in plants, relatively few genes regulating this process have been identified to date. By using data from detailed transcript profiling of the poplar wood‐forming tissues, 150 genes that are differentially expressed within the zone of secondary growth were identified. In order to determine the possible function of these poplar genes, potential Arabidopsis thaliana orthologs were identified and gene knockout lines analysed. Three selection filters were used to identify the most likely orthologous genes using poplar and Arabidopsis sequence comparisons, expression profiling in secondary thickened Arabidopsis hypocotyls and global expression analysis of Arabidopsis tissues. Three genes encoding AtCSLA2 (At5g22740), the AtGUT1 GT47 glycosyltransferase (At1g27440) and a protein with no proposed function AtUNKA (At4g27435) were selected for further detailed analysis of their role in secondary growth in Arabidopsis. The presented genome‐based approach using both poplar and Arabidopsis systems provides powerful means towards assigning biological functions to enzymes with poorly understood biochemical activity, such as AtCSLA2 and AtGUT1, as well as for proteins with no known function.
A Myb transcription factor (TaMyb1) from wheat roots is expressed during hypoxia: roles in response to the oxygen concentration in root environment and abiotic stresses
Authors: Lee Tong Geon , Jang Cheol Seong , Kim Jae Yoon , Kim Dong Sub , Park Jae Han , Kim Dae Yeon , Seo Yong Weon
Published: November 2006

Oxygen deficiency is one of the major stresses to plants under waterlogging. A low‐oxygen‐signaling pathway is the most important mechanism for adaptation and survival under anaerobic conditions. To find genes related to the oxygen concentration in root environment in common wheat roots, we investigated the transcriptional expression in vitro for low‐oxygen treatment. Dramatic increases in the transcripts of a TaMyb1 (Triticum aestivum Myb transcription factor 1) gene occurred under hypoxia. Presence of TaMyb1 on the 3BL was confirmed by using Chinese Spring aneuploid accessions including nullisomic–tetrasomic and ditelosomic lines. The transcriptional expression of TaMyb1 was continued until approximate anoxia, being enhanced by light under hypoxia, but little expression during anoxia could be shown by Northern hybridization. The TaMyb1 expression was high in the epidermis, endodermis and the cortex adjacent to the endodermis under hypoxia but undetectable in the vascular tissues or cortex, which contained aerenchyma. TaMyb1 transcription levels in roots gradually increased as the result of treatment with NaCl. Slight increases in expression were noted during the early stages of exogenous treatment of with both abscisic acid and polyethylene glycol. Little and constant expressions were detected as the result of citric acid treatment. Our data suggested that the expression of TaMyb1 in roots could be strongly related to the oxygen concentration in root environment and the wheat plant responses to abiotic stresses.
Mate Choice and Spawning Success in the Fighting FishBetta splendens: the Importance of Body Size, Display Behavior and Nest Size
Authors: Clotfelter Ethan D. , Curren Leslie J. , Murphy Caleb E.
Published: November 2006

Courtship displays should be exaggerated enough to attract mates and yet tempered so as not to deter them. We tested this hypothesis in the fighting fishBetta splendensby studying courtship displays and body size and their relationships with male parental quality and female fecundity, as well as the effects of display behavior and body size on mate choice decisions and spawning success. Because of their high degree of parental investment, males are expected to be discriminating in their choice of mates. Males who displayed more frequently built larger nests, a measure of parental quality, but larger males did not. When females were paired with males with high display rates, however, the pair had fewer eggs in their nest, even when accounting for female body mass. In a mate choice test using computer‐generated male stimuli that differed only in display behavior, females showed no preferences for displaying males vs. non‐displaying males, or for males with higher display rates vs. lower display rates. In similar tests in which the computer‐generated males differed only in size, females preferred larger males, but also preferred males that differed with respect to body size (negative assortative mating). Males preferred computer‐generated females that performed courtship displays over non‐displaying females, but showed no preferences for female body size. Neither a female's body size nor her display behavior was a significant predictor of her fecundity as estimated by the number of eggs released during spawning. Thus, our results suggest that femaleB. splendensmust balance male parental quality (nest size) with the risk of potentially disruptive or dangerous behavior during spawning, and that females may minimize these risks through negative size‐assortative mating. Female display behavior, while unrelated to fecundity in our study, may attract males because it indicates reproductive readiness or serves a species‐recognition function.