bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of land use on stream ecosystem function in a Mediterranean catchment
Authors: VON SCHILLER D. , MARTÍ E. , RIERA J. L. , RIBOT M. , MARKS J. C. , SABATER F.
Published: July 2008

1. Due to the hierarchical organization of stream networks, land use changes occurring at larger spatial scales (i.e. the catchment) can affect physical, chemical and biological characteristics at lower spatial scales, ultimately altering stream structure and function. Anthropogenic effects on streams have primarily been documented using structural metrics such as water chemistry, channel alteration and algal biomass. Functional parameters, including metrics of nutrient retention and metabolism, are now being widely used as indicators of stream condition.

2. Within this hierarchical context, we used a multivariate approach to examine how structural and functional (i.e. nutrient retention and metabolism) attributes of streams are related to catchment variables, including land use. The study was done in 13 streams located within a single Mediterranean catchment, but draining sub‐catchments with contrasting land use.

3. At the catchment scale, results showed two contrasting land use gradients: (i) from forested‐ to urban‐dominated catchments and (ii) from low to moderate agricultural‐dominated catchments. Variation in structural and functional parameters was strongly related to these land use gradients. Specifically, NH4+ demand (measured as the uptake velocity, Vf) decreased along the gradient from forested‐ to urban‐dominated catchments primarily in response to increases in stream nutrient concentrations [NH4+, dissolved organic nitrogen (DON) and carbon (DOC)]. Both primary production and respiration increased along the gradient of agricultural development in response to increases in algal biomass (chlorophyll a). Soluble reactive phosphorus demand was not related to any of the land use gradients.

4. Our results illustrate the connections among factors operating at different spatial scales (i.e. from catchments to streams) and their distinct influence on stream ecosystem function. Managers should take into consideration these connections when designing stream management and restoration plans. Because ecologically successful stream management and restoration is expected to restore function as well as structure to streams, the use of appropriate measures of functional processes is required. Nutrient retention and metabolism parameters are good candidates to fill this gap.
Using computer assisted learning for clinical skills education in nursing: integrative review
Authors: Bloomfield Jacqueline G. , While Alison E. , Roberts Julia D.
Published: July 2008

Title.  Using computer assisted learning for clinical skills education in nursing: integrative review.

Aim.  This paper is a report of an integrative review of research investigating computer assisted learning for clinical skills education in nursing, the ways in which it has been studied and the general findings.

Background.  Clinical skills are an essential aspect of nursing practice and there is international debate about the most effective ways in which these can be taught. Computer assisted learning has been used as an alternative to conventional teaching methods, and robust research to evaluate its effectiveness is essential.

Data sources.  The CINAHL, Medline, BNI, PsycInfo and ERIC electronic databases were searched for the period 1997–2006 for research‐based papers published in English. Electronic citation tracking and hand searching of reference lists and relevant journals was also undertaken.

Findings.  Twelve studies met the inclusion criteria. An integrative review was conducted and each paper was explored in relation to: design, aims, sample, outcome measures and findings. Many of the study samples were small and there were weaknesses in designs. There is limited empirical evidence addressing the use of computer assisted learning for clinical skills education in nursing. Computer assisted learning has been used to teach a limited range of clinical skills in a variety of settings.

Conclusion.  The paucity of evaluative studies indicates the need for more rigorous research to investigate the effect of computer assisted learning for this purpose. Areas that need to be addressed in future studies include: sample size, range of skills, longitudinal follow‐up and control of confounding variables.
Implementing nursing diagnostics effectively: cluster randomized trial
Authors: Müller‐Staub Maria , Needham Ian , Odenbreit Matthias , Lavin Mary Ann , Van Achterberg Theo
Published: July 2008

Title.  Implementing nursing diagnostics effectively: cluster randomized trial.

Aim.  This paper is a report of a study to investigate the effect of guided clinical reasoning. This method was chosen as a follow‐up educational measure (refresher) after initial implementation of standardized language.

Background.  Research has demonstrated nurses’ need for education in diagnostic reasoning to state and document accurate nursing diagnoses, and to choose effective nursing interventions to attain favourable patient outcomes.

Methods.  In a cluster randomized controlled experimental study, nurses from three wards received guided clinical reasoning, an interactive learning method. Three wards, receiving classic case discussions, functioned as control group. Data were collected in 2004–2005. The quality of 225 randomly selected nursing records, containing 444 documented nursing diagnoses, corresponding interventions and outcomes was evaluated by applying 18 Likert‐type items with a 0–4 scale of the instrument Quality of Nursing Diagnoses, Interventions and Outcomes. The effect of guided clinical reasoning was tested against classic case discussions using T‐tests and mixed effects model analyses.

Findings.  The mean scores for nursing diagnoses, interventions and outcomes increased significantly in the intervention group. Guided clinical reasoning led to higher quality of nursing diagnosis documentation; to aetiology‐specific interventions and to enhanced nursing‐sensitive patient outcomes. In the control group, the quality was unchanged.

Conclusion.  Guided clinical reasoning supported nurses’ abilities to state accurate nursing diagnoses, to select effective nursing interventions and to reach and document favourable patient outcomes. The results support the use of the North American Nursing Diagnosis Association, Nursing Interventions Classification and Nursing Outcomes Classification classifications and demonstrate implications for the electronic nursing documentation.
The role of inter‐professional relationships and support for nurse prescribing in acute and chronic pain
Authors: Stenner Karen , Courtenay Molly
Published: July 2008

Title.  The role of inter‐professional relationships and support for nurse prescribing in acute and chronic pain.

Aim.  This paper is a report of a study to explore nurse prescribers’ views on the role of inter‐professional relationships and other means of support for nurse prescribing for patients in acute and chronic pain.

Background.  Research indicates that good team relationships are important for supporting nurse prescribing but that poor understanding of the role by other healthcare professionals can act as a barrier. While collaborative working is central to the role of pain nurses, there is a lack of research on the impact of nurse prescribing on inter‐professional working or the support needs of these nurses.

Method.  A qualitative approach was adopted using thematic analysis of semi‐structured interview data collected during 2006 and 2007. Participants were 26 nurses who prescribed medicines for patients with acute and/or chronic pain.

Findings.  Nurses’ believed that prescribing encouraged collaborative working and sharing of knowledge across professional boundaries and that this helped to broaden understanding of the wider remit of pain management. Collaboration with doctors served a number of functions, including support and continuous learning. Barriers to effective nurse prescribing were a lack of understanding of its role amongst healthcare professionals and inadequate support. Formal support structures, such as regular clinical supervision, were seen as crucial to meeting nurses’ ongoing learning.

Conclusion.  Factors that promote understanding of nurse prescribing and support inter‐professional relationships are likely to have a positive impact on the effectiveness of nurse prescribing. A more consistent approach is required within organisations to support nurse prescribing.
Childbirth‐related fatigue trajectories during labour
Authors: Tzeng Ya‐Ling , Chao Yu‐Mei Y. , Kuo Shu‐Yu , Teng Yu Kuei
Published: July 2008

Title.  Childbirth‐related fatigue trajectories during labour.

Aim.  This paper is a report on a study identifying trajectories of childbirth‐related fatigue intensity changes over time and the influencing factors related to specific trajectory patterns.

Background.  Childbirth is a period of time that encompasses considerable physiological and psychological fatigue, often having an adverse impact on women in labour. Empirical studies on this issue are scarce. How childbirth‐related fatigue changes over time, and factors influencing fatigue development, remain unclear.

Method.  A prospective, correlational design with repeated measures was used. Data were collected by self‐reported measures and laboratory analysis of blood specimens. From December 2004 to November 2005 a convenience sample of 209 low‐risk pregnant Taiwanese women was followed throughout the labour process. Repeated measures of fatigue were analysed by using a semiparametric mixture model. Variables explaining trajectory class membership were identified by means of logistic regression.

Results.  Two distinct trajectories of childbirth‐related fatigue were identified: low intensity (30·8% of women) and high intensity (69·2% of women). Fatigue level of both classes intensified following labour. The fastest period of fatigue‐increasing rate was in the active phase. After birth, fatigue levels in the high‐fatigue intensity class remained high. Primiparas in the high‐fatigue intensity class experienced significantly more anxiety and higher lactate concentration at admission than the low‐intensity class.

Conclusion.  Caregivers should endeavour to prevent high levels of fatigue once women enter the labour phase. Women who present with high fatigue at onset of labour should be targeted for early intervention, especially in the period of rapid fatigue increase.
Learning to teach with worked‐out examples: a computer‐based learning environment for teachers
Authors: Hilbert T.S. , Renkl A. , Schworm S. , Kessler S. , Reiss K.
Published: July 2008

Abstract  Learning from worked‐out examples has been shown to be very effective in initial cognitive skill acquisition. In order to fully exploit the potential of example‐based learning, teachers should, however, know how to effectively employ such examples in classroom instruction. Therefore, we have designed a computer‐based learning environment in which mathematics and science teachers learn how to effectively employ worked‐out examples. The learning environment was developed according to approved design criteria. The topics that are addressed in the learning environment were chosen in response to the results of a needs assessment that analysed schoolbooks and classroom videos, and took interviews with teachers into account. In experiments as well as in several teacher trainings on example‐based learning, the computer‐based learning environment was evaluated and improved accordingly. On a more general level, our research and development project showed that a computer‐based learning programme could be a sensible tool that supports follow‐up work in teacher training contexts.
Antibiotics for nasopharyngitis are associated with a lower risk of office‐based physician visit for acute otitis media within 14 days for 3‐ to 6‐year‐old children
Authors: Salomon Jérôme , Sommet Agnès , Bernède Claire , Tonéatti Christine , Carbon Claude , Guillemot Didier
Published: July 2008

Objectives  This study was designed to analyse factors potentially influencing children's return visits to physicians for symptoms of acute otitis media (AOM) within 14 days after being diagnosed with nasopharyngitis (NP), and the impact of recent antibiotic use.

Design  A controlled population‐based pharmaco‐epidemiological trial in 3‐ to 6‐year‐old children conducted from January to May 2000.

Setting  Three different geographical regions in France.

Participants  Among 2507 eligible children, 2456 could be analysed and 505 children had 634 office‐based physician visits (OBPV) for NP symptoms.

Interventions  The statistical associations between antibiotics prescribed for NP and an OBPV for AOM within 14 days in a population‐based study were analysed along with risk factors of AOM.

Main outcomes measure  Clinical events and antibiotic use.

Results  During the 2 weeks following physician‐diagnosed NP, antibiotic use, especially a beta‐lactam, significantly decreased the risk of OBPV for AOM in children (odds ratio = 0.2; 95% confidence interval = 0.09–0.7; P = 0.002).

Conclusion  Antibiotics prescribed to children for NP seem to protect during the following 2 weeks against the risk of OBPV for AOM. It remains to be determined whether a subgroup at high risk of developing AOM after a viral infection exists and what might be the best strategy to adopt for NP in a national programme of optimal antibiotic use.
The effectiveness of nurse‐led telemonitoring of asthma: results of a randomized controlled trial
Authors: Willems Daniëlle C. M. , Joore Manuela A. , Hendriks Johannes J. E. , Nieman Fred H. M. , Severens Johan L. , Wouters Emiel F. M.
Published: July 2008

Rationale, aims and objectives  The aim of the study was to evaluate the effects on, and the relationship between, asthma symptoms, asthma‐specific quality of life and medical consumption of a nurse‐led telemonitoring intervention compared with regular care in asthma in the Netherlands.

Methods  One hundred and nine asthmatic outpatients (56 children; 53 adults) were randomly assigned to the treatment arms (12‐month follow‐up). The control group received regular outpatient care, while the intervention group used an asthma monitor with modem at home with an asthma nurse as the main caregiver. Clinical asthma symptoms and medical consumption were measured by using diaries. Asthma‐specific quality of life was measured by the (Paediatric) Asthma Quality of Life Questionnaire.

Results  The study population generally represented mild to moderate asthmatics. The results show improvement in follow‐up, but no statistically significant difference between the groups was observed. Moderate to high correlations were found within the outcome parameters, but the most remarkable was the low and statistically significant correlation between asthma‐specific quality of life (daily functioning) and the self‐reported beta‐2 agonists.

Conclusion  Overall, the telemonitoring programme evaluated in this study did not significantly decrease asthma symptoms or medical consumption, or improve asthma‐specific quality of life. The results showed that a telemonitoring programme on its own is not a guarantee of success. The patients' perception of asthma‐specific quality of life (daily functioning) should be a key element in asthma telemonitoring programmes.
Exploring dietitians’ verbal and nonverbal communication skills for effective dietitian–patient communication
Authors: Cant R. P. , Aroni R. A.
Published: July 2008

Background  Little is known about how dietitians conduct their communication with individual patients in the process of nutrition education. To study this issue, both practitioners’ and patients’ perceptions of dietitians’ skills were examined in the first phase of a two‐phase study. The resulting narratives were used to develop a questionnaire to survey Australian dietitians involved in clinical practice.

Methods  A purposive sample of dietitians in one state (n = 46; 12%), working in hospital, community or private practice, and a quota of their adult patients (n = 34), were interviewed. In the second stage, Australian dietitians (n = 258; 16%) responded to a national survey in 2006, which asked about educational strategies, communication skills, and professional attributes. Descriptive statistics were used to compare response distributions, and nonparametric statistics were used to examine between‐group relationships. Criterion for item acceptance was established as ≥70% agreement. Triangulation of results revealed strong agreement between data sources.

Results  Four main communication competencies were established: interpersonal communication skill, nonverbal communication, professional values, and counselling skill. There was no significant difference in practice by work category or experience. The communication competencies, together with 26 accompanying skills, are described.

Conclusion  An understanding of this guide to communication practice might help enhance dietitian–patient relations.
Self‐reported chewing side preference and its associations with occlusal, temporomandibular and prosthodontic factors: results from the population‐based Study of Health in Pomerania (SHIP‐0)
Authors: DIERNBERGER S. , BERNHARDT O. , SCHWAHN C. , KORDASS B.
Published: July 2008

Summary  This study investigated the prevalence of a preferred chewing side (PCS) and associations between a PCS and signs of temporomandibular disorders (TMD), antagonist contact and prosthetic restoration. A population representative sample of 4086 adults of the cross‐sectional epidemiologic ‘Study of Health in Pomerania’ (SHIP‐0) (age range 20–80 years, female 50·2%) was divided in two groups by the presence or absence of a PCS. PCS was evaluated by a questionnaire. Chi‐squared tests and multiple logistic regression were used to determine the impact of the relation between a PCS and signs and symptoms of TMD as well as dental factors. The prevalence of a PCS was 45·4%. Women between 40 and 69 years reported more frequently a PCS. There was a preference for the right side (64%). The following independent variables were significantly associated with a PCS: subjective unilateral pain in the temporomandibular joint (TMJ), odds ratio (OR) 2·4; subjective unilateral joint clicking, OR 1·7; unilateral TMJ/muscle pain on palpation, OR 1·6/OR 1·3; loss of one supporting zone (Eichner‐Classification), OR 1·9; loss of both supporting zones on one side, OR 2·2, one supporting zone left, OR 1·4; presence of a removable partial denture, OR 1·6; presence of an attachment restoration, OR 1·5. A PCS was found in almost half the study population and was associated with unilateral signs of TMD, most of all TMJ pain and asymmetrical loss of antagonist contact. Despite replacement of lost teeth not all restorations seemed to support bilateral mastication.
Patterns of missing occlusal units and oral health‐related quality of life in SDA patients
Authors: BABA K. , IGARASHI Y. , NISHIYAMA A. , JOHN M. T. , AKAGAWA Y. , IKEBE K. , ISHIGAMI T. , KOBAYASHI H. , YAMASHITA S.
Published: July 2008

Summary  The aim of this study was to explore the relationship between patterns of missing occlusal units (OUs) and oral health‐related quality of life (OHRQoL) in subjects with the shortened dental arches (SDAs). Subjects with SDAs were recruited consecutively for 1 month from six university‐based prosthodontic clinics. In total, 115 SDA subjects participated (mean age, 58·5 ± 10·0 years; 71% female). The location and number of missing teeth were examined and the number of missing OUs was calculated. To evaluate OHRQoL, the Japanese version of the Oral Health Impact Profile (OHIP‐J) was administered and the summary score of OHIP‐J was calculated. The SDA subjects were categorized depending upon the anterior‐posterior lengths of the missing or remaining OUs. Regression analyses were performed to investigate the OHIP‐J differences between groups of subjects with various anterior–posterior SDA lengths. The analyses revealed that subjects who only lost the second molar contact exhibited significantly better OHRQoL than those who lost more teeth [coefficient: 11·1, 95% confidence interval (CI): 2·8–19·2, P = 0·02]. Furthermore a statistically significant group difference was observed between the groups with and without the first molar occlusal contact (coefficient: 12·8, 95% CI: 1·4 to 24·1, P = 0·03). In conclusion, although our results are of exploratory nature and need validation, patterns of missing OUs are likely to be related to the OHRQoL impairment in SDA subjects with the presence of first molar contact having a particularly important role.
Time‐variant nature of sleep bruxism outcome variables using ambulatory polysomnography: implications for recognition and therapy evaluation
Authors: VAN DER ZAAG J. , LOBBEZOO F. , VISSCHER C. M. , HAMBURGER H. L. , NAEIJE M.
Published: July 2008

Summary  The aim of this study was to quantify the time‐variant nature of sleep bruxism (SB) and to discuss its consequences. Six clinically diagnosed bruxers and six non‐bruxers participated. Four ambulatory polysomnographic (PSG) recordings were obtained for every participant. As SB outcome variables, the number of episodes per hour of sleep (Epi h−1), the number of bursts per hour (Bur h−1) and the bruxism time index (BTI: the percentage of total sleep time spent bruxing) were established. To quantify the time‐variant nature of SB, standard errors of measurement (SEMs) were calculated. For the non‐bruxers, the SEMs for Epi h−1, Bur h−1 and BTI were 1·0, 5·7 and 0·1. For the bruxers, the respective values were 2·1, 14·9 and 0·4. In the discussion, arguments are given that because of the time‐variant nature of the PSG recordings, cut‐off bands around cut‐off points might be useful for the recognition of SB.
Comparative efficacy of maropitant and selected drugs in preventing emesis induced by centrally or peripherally acting emetogens in dogs
Authors: SEDLACEK H. S. , RAMSEY D. S. , BOUCHER J. F. , EAGLESON J. S. , CONDER G. A. , CLEMENCE R. G.
Published: July 2008

Maropitant (Cerenia™; a novel, selective neurokinin1 receptor antagonist), chlorpromazine, metoclopramide and ondansetron were compared in two randomized, placebo‐controlled studies for efficacy in preventing emesis induced by emetogens acting centrally (apomorphine; Study 1) or peripherally (syrup of ipecac; Study 2) in dogs. In each study, ten male and ten female beagles were treated in a five‐treatment, five‐period crossover design. The five treatments were 0.9% saline (0.1 mL/kg), maropitant (1 mg/kg), metoclopramide (0.5 mg/kg), or chlorpromazine (0.5 mg/kg) all administered subcutaneously, or ondansetron (0.5 mg/kg) administered intravenously. One hour posttreatment dogs were challenged with apomorphine at 0.1 mg/kg intravenously (Study 1) or syrup of ipecac at 0.5 mL/kg orally (Study 2). Following emetogen challenge, dogs were observed for 30 min (Study 1) or 1 h (Study 2) for emesis. No clinical signs, other than those related to emesis, were observed. Efficacy of maropitant in preventing emesis induced centrally by apomorphine was not different (P > 0.05) from metoclopramide or chlorpromazine but was superior (P < 0.0001) to ondansetron. Efficacy of maropitant in preventing emesis induced by syrup of ipecac was not different (P > 0.05) from ondansetron but was superior (P ≤ 0.0102) to metoclopramide or chlorpromazine. Maropitant was effective (P < 0.0001 relative to control) in preventing vomiting caused by stimulation of either central or peripheral emetic pathways, whereas the other drugs examined prevented vomiting caused by central (metoclopramide and chlorpromazine; P < 0.0001) or peripheral (ondansetron; P < 0.0001) stimulation but not both.
Two essential MYST‐family proteins display distinct roles in histone H4K10 acetylation and telomeric silencing in trypanosomes
Authors: Kawahara Taemi , Siegel T. Nicolai , Ingram Alexandra K. , Alsford Sam , Cross George A. M. , Horn David
Published: July 2008

Chromatin modification is important for virtually all aspects of DNA metabolism but little is known about the consequences of such modification in trypanosomatids, early branching protozoa of significant medical and veterinary importance. MYST‐family histone acetyltransferases in other species function in transcription regulation, DNA replication, recombination and repair. Trypanosoma brucei HAT3 was recently shown to acetylate histone H4K4 and we now report characterization of all three T. brucei MYST acetyltransferases (HAT1–3). First, GFP‐tagged HAT1–3 all localize to the trypanosome nucleus. While HAT3 is dispensable, both HAT1 and HAT2 are essential for growth. Strains with HAT1 knock‐down display mitosis without nuclear DNA replication and also specific de‐repression of a telomeric reporter gene, a rare example of transcription control in an organism with widespread and constitutive polycistronic transcription. Finally, we show that HAT2 is responsible for H4K10 acetylation. By analogy to the situation in Saccharomyces cerevisiae, we discuss low‐level redundancy of acetyltransferase function in T. brucei and suggest that two MYST‐family acetyltransferases are essential due to the absence of a Gcn5 homologue. The results are also consistent with the idea that HAT1 contributes to establishing boundaries between transcriptionally active and repressed telomeric domains in T. brucei.
Occurrence and molecular characterization of Turkish isolates of Turnip mosaic virus
Authors: Korkmaz S. , Tomitaka Y. , Onder S. , Ohshima K.
Published: July 2008

A total of 142 samples of plants showing symptoms of Turnip mosaic virus (TuMV) were collected from fields planted to Brassicaceae and non‐Brassicaceae crops in the southwest Marmora region of Turkey, during the 2004−06 growing seasons. Using enzyme‐linked immunosorbent assay (ELISA) TuMV was detected in the main brassica‐crop fields of Turkey, with an overall incidence of 13·4%. TuMV was detected in samples from Brussels sprouts, cabbage, wild mustard, radish and wild radish, but not cauliflower or broccoli. The full‐length sequences of the genomic RNAs of two biologically distinct isolates, TUR1 and TUR9, were determined. Recombination analyses showed that TUR1 was an intralineage recombinant, whereas TUR9 was a non‐recombinant. Phylogenetic analyses of the Turkish isolates with those from the rest of the world showed that the TUR1 and TUR9 isolates belonged to world‐Brassica and Asian‐Brassica/Raphanus groups, respectively. This study showed that TuMV is widely distributed in the Asia Minor region of Turkey.
Induced expression of sucrose synthase and alcohol dehydrogenase I genes in phytoplasma‐infected grapevine plants grown in the field
Authors: Hren M. , Ravnikar M. , Brzin J. , Ermacora P. , Carraro L. , Bianco P. A. , Casati P. , Borgo M. , Angelini E. , Rotter A. , Gruden K.
Published: July 2008

Interaction between phytoplasma and grapevine at the physiological level is still poorly understood, as are plant defence mechanisms against the pathogen. This study investigates the level of gene expression of three selected genes in a large number of grapevine plants belonging to six disease/cultivar groups (healthy Chardonnay, Bois noir‐infected Chardonnay, Flavescence dorée‐infected Barbera and Prosecco, and recovered Barbera and Prosecco). All plants were grown in vineyards in uncontrolled conditions in order to represent the physiology of disease as accurately as possible. Sucrose synthase was significantly upregulated in infected plants of all cultivars with the lowest P‐values in cvs Chardonnay and Prosecco (P < 0·001) and median fold‐change around 2. This clearly indicates that carbohydrate metabolism changed in infected compared to healthy or recovered plants. Alcohol dehydrogenase I was significantly upregulated in infected relative to healthy Chardonnay plants (P < 0·05) indicating that alcoholic fermentation, a sign of hypoxic conditions, was induced in infected plants. Heat shock protein 70 was upregulated in infected compared to recovered plants only in cv. Prosecco. Linear discriminant analysis showed that classification of samples into disease status groups based on gene expression was highly accurate (82%), indicating that the response of field‐grown plants to phytoplasma infection at the level of expression of selected genes was so intensive and uniform that it was possible to detect it in grapevine plants regardless of natural variables.
Chestnut blight fungus in Croatia: diversity of vegetative compatibility types, mating types and genetic variability of associated Cryphonectria hypovirus 1
Authors: Krstin L. , Novak‐Agbaba S. , Rigling D. , Krajačić M. , Ćurković Perica M.
Published: July 2008

In order to improve understanding of its diversity, 338 isolates of Cryphonectria parasitica, the causal agent of chestnut blight, were sampled from 10 chestnut populations throughout chestnut‐growing coastal and continental areas of Croatia. Eighteen vegetative compatibility (VC) types were identified. The VC type EU‐1 was the most widespread, comprising 42·9% of the isolates, followed by EU‐2 (21%) and EU‐12 (14·2%). In respect to the occurrence of the main VC types, the C. parasitica populations in Croatia combined features of both northwestern and southeastern European populations. Perithecia and mating‐type ratios of approximately 1 : 1 were found in all populations, suggesting that sexual reproduction of the fungus is common in Croatia. Natural hypovirulence was also evident in all populations, with incidence of hypovirus‐infected isolates ranging from 12·7% in Istria‐Buje to 66·6% in the continental part of the country. A total of 36 hypovirus‐infected isolates sampled throughout Croatia were analysed in ORF‐A and ORF‐B by RT‐PCR/RFLP analysis. All viral isolates belonged to the Italian subtype of Cryphonectria hypovirus 1 (CHV‐1) and were closely related to the isolates found in other European countries. The RFLP patterns found were also identical or similar to the patterns of three isolates collected in Croatia 22 years ago, suggesting a slow evolution of the hypovirus.
Dolomite–silica stromatolites in Miocene lacustrine deposits from the Duero Basin, Spain: the role of organotemplates in the precipitation of dolomite
Authors: SANZ‐MONTERO MARÍA E. , RODRÍGUEZ‐ARANDA JUAN P. , GARCÍA DEL CURA MARÍA A.
Published: July 2008

This research provides an ancient analogue for biologically mediated dolomite precipitation in microbial mats and biofilms, and describes the involvement of highly structured extracellular polymeric secretion (EPS) templates in dolomite nucleation. The structure of EPS is shown to match the hexagonal–trigonal lattice geometry of dolomite, which favoured the epitaxial crystallization of dolomite on the organic substrate. This structure of EPS also matches the arrangement of silica nanospheres in opal, which further accounts for the organically‐templated formation of opal enabling the non‐replacive co‐existence of dolomite and silica. The study is focused on a 50 m thick dolomite succession that is exposed in central areas of the Tertiary Duero Basin and was deposited in a mudflat‐saline lake sedimentary complex during the Middle to Late Miocene (9 to 15 Ma). In the intermediate intervals of the succession, poorly indurated dolomite beds pass gradually into silica beds. On the basis of sedimentological, compositional, geochemical and petrographic data, silica and dolomite beds have been interpreted as mineralized microbial mats. The silica beds formed in marginal areas of the lake in response to intense evaporative concentrations; this resulted in the rapid and early precipitation of opal. Silicification accounted for the exceptional preservation of the microbial mat structure, including biofilms, filamentous and coccoid microbes, and EPS. Extracellular polymeric secretions have a layered structure, each layer being composed of fibres which are arranged in accordance with a reticular pattern, with frequent intersection angles at 120° and 60°. Therefore, the structure of EPS matches the lattice geometry of dolomite and the arrangement of silica nanospheres in opal. Additionally, EPS binds different elements, with preference to Si and Mg. The concurrence of suitable composition and surface lattice morphologies in the EPS favoured the crystallization of dolomite on the substrate. In some cases, dolomite nucleation took place epicellularly on coccoid micro‐organisms, which gave way to spheroid crystals. Organic surfaces enable the inorganic mineral precipitation by lowering the free energy barrier to nucleation. Most of the microbial mats probably developed on the lake floor, under sub‐aqueous conditions, where the decomposition of organic matter took place. The subsequent formation of openly packed dolomite crystals, with inter‐related Si‐enriched fibrils throughout, is evidence for the pre‐existence of fibrillar structures in the mats. Miocene dolomite crystals are poorly ordered and non‐stoichiometric, with a slight Ca‐excess (up to 5%), which is indicative of the low diagenetic potential the microbial dolomite has towards a more ordered and stoichiometric structure; this confirms that microbial imprints can be preserved in the geological record, and validates their use as biosignatures.
Biosedimentology of the Early Jurassic post‐extinction carbonate depositional system, central High Atlas rift basin, Morocco
Authors: WILMSEN MARKUS , NEUWEILER FRITZ
Published: July 2008

This study documents a Liassic example of the long‐ranging effects of mass extinction on carbonate systems. Biohistoric constraints inherent in the Liassic carbonate depositional system are deciphered from normal‐marine, sub‐tidal deposits of the central High Atlas rift basin (Morocco) through ?Hettangian/Sinemurian to Early Toarcian times. The integration of results from the analysis of lithofacies, depositional geometries, microfacies, macrobenthos, carbonate build‐ups, carbon and oxygen stable isotopes, and rare earth element + yttrium distribution patterns allows the intrinsic (or biohistoric) control on the central High Atlas deposits to be separated from extrinsic factors, such as basin development and palaeoclimate. The survival interval in the aftermath of the end‐Triassic mass extinction persisted until the Early Sinemurian indicated by a severely depleted carbonate system impoverished in skeletal organisms. A tectonic pulse at the Early to Late Sinemurian boundary interval caused a basin widening with immigration of a marine fauna. However, until the latest Sinemurian (macdonelliSubzone of theraricostatumZone) the deposits were dominated by filter‐feeding benthic heterotrophs (sponges, brachiopods, polychaetes and crinoids). During this stage, primary production within the enlarged basin must have been largely planktonic and there was a net‐flux of organic matter to the sea floor (oxygen minimum zone). A regional radiation of organic‐walled phytoplankton is inferred to explain the selective success of the filter‐feeding community and the occurrence of sponge mounds. Thus, significant effects of the end‐Triassic mass extinction are still present during the Late Sinemurian. Through almost the entire Pliensbachian a highly productive, shoal‐rimmed carbonate platform existed; it developed subsequent to tectonic reorganization and a marine recirculation event (radiolarian facies, Δδ13C ≈ −1·1, strongly negative Ce‐anomaly). Photosymbiotic sediment producers (mainly large bivalves) now state the success of specialists and environmental equilibrium conditions. In the latest Pliensbachian the climax stage was reached with the development of a coralgal reef‐rimmed carbonate platform. The Liassic carbonate depositional system experienced a terminal, multicausal Early Toarcian drowning event during which most of the large bivalves became extinct.
Trace fossils as diagnostic indicators of deep‐marine environments, Middle Eocene Ainsa‐Jaca basin, Spanish Pyrenees
Authors: HEARD THOMAS G. , PICKERING KEVIN T.
Published: July 2008

A quantitative study of trace fossil abundance in the Middle Eocene deep‐marine clastic systems, Ainsa‐Jaca basin, Spanish Pyrenees, shows that they are powerful discriminators of submarine fan and related environments. Sixteen fan and related environments are recognized from upper‐slope gully to the distal basin‐floor. For each environment, the degree of bioturbation (density), trace‐fossil diversity, number of pre‐depositional and post‐depositional trace fossils, as well as the number of graphoglyptid ichnospecies were quantified. In the more laterally confined and channel‐dominated Ainsa basin, there is a trend of increasing bioturbation intensity and trace‐fossil diversity away from channel‐axis to off‐axis environments. In the more unconfined and distal Jaca basin, there is a trend of increasing trace‐fossil diversity and number of pre‐depositional trace fossils including graphoglyptids from the channel‐lobe transition to the fan‐fringe. The trace‐fossil assemblages of the Ainsa‐Jaca basin are characteristic of a number of sub‐ichnofacies of the Nereites ichnofacies. In the distal Jaca basin, the Paleodictyon sub‐ichnofacies occurs in the lobe‐fringe and fan‐fringe, whereas the distal basin‐floor has a trace‐fossil assemblage typical of the Paleodictyon sub‐ichnofacies, but with a high proportion of post‐depositional fodinichnia. Trace‐fossil assemblages of proximal basin, axial, environments are characteristic of the Ophiomorpha rudis sub‐ichnofacies, whilst proximal off‐axis environments, have a mixed Paleodictyon‐Ophiomorpha rudis sub‐ichnofacies trace‐fossil assemblage.
The influence of hydrology and climate on the isotope geochemistry of playa carbonates: a study from Pilot Valley, NV, USA
Authors: LIUTKUS CYNTHIA M. , WRIGHT JAMES D.
Published: July 2008

Carbonates often accompany lake and lake‐margin deposits in both modern and ancient geological settings. If these carbonates are formed in standing water, their stable isotope values reflect the aquatic chemistry at the time of precipitation and may provide a proxy for determining regional hydrologic conditions. Carbonate rhizoliths and water samples were collected from a playa lake in eastern Nevada. Pilot Valley (∼43°N) is a closed‐basin, remnant playa from the Quaternary desiccation of palaeo‐Lake Bonneville. Water is added to the playa margin by free convection of dense brines to the east and forced convection of freshwater off the alluvial fan to the west. Both freshwater and saline springs dot the playa margin at the base of an alluvial fan. Water samples collected from seven springs show a range from −16 to −0·2‰ (Vienna Standard Mean Ocean Water), and are consistent with published values. The δ18Ocalcite values from rhizolith samples range from −18·3 to −6·7‰ (Vienna Pee Dee Belemnite), and the average is −12‰ V‐PDB (1 − σ SD 2‰). With the exception of samples from Little Salt Spring, the range in the δ18Ocalcite values collected from the rhizoliths confirms that they form in equilibrium with ambient water conditions on the playa. The initial geochemical conditions for the spring waters are dictated by local hydrology: freshwater springs emerge in the northern part of the basin to the east of a broad alluvial fan, and more saline springs emerge to the south where the influence of the alluvial fan diminishes. Rhizoliths are only found near the southern saline springs and their δ13Ccalcite values, along with their morphology, indicate that they only form around saltgrass (Distichlis sp.). As the residence time of water on the playa increases, evaporation, temperature change and biological processes alter the aquatic chemistry and initiate calcite precipitation around the plant stems. The range in δ18Ocalcite values from each location reflects environmental controls (e.g. evaporation and temperature change). These rhizoliths faithfully record ambient aquatic conditions during formation (e.g. geochemistry and water depth), but only record a partial annual signal that is constrained by saltgrass growth and the presence of standing water on the playa margin.
Architecture and evolution of the Paine channel complex, Cerro Toro Formation (Upper Cretaceous), Silla Syncline, Magallanes Basin, Chile
Authors: CRANE WILLIAM H. , LOWE DONALD R.
Published: July 2008

The Upper Cretaceous Cerro Toro Formation in the Silla Syncline, Parque Nacional Torres del Paine, Magallanes Basin, Chile, includes over 1100 m of mainly thin‐bedded mud‐rich turbidites containing three thick divisions of coarse conglomerate and sandstone. Facies distributions, stacking patterns and lateral relationships indicate that the coarse‐grained sandstone and conglomerate units represent the fill of a series of large south to south‐east trending deep‐water channels or channel complexes. The middle coarse division, informally named the Paine member, represents the fill of at least three discrete channels or channel complexes, termed Paine A, B and C. The uppermost of these, Paine C, represents a channel belt about 3·5 km wide and its fill displays explicit details of channel geometry, channel margins, and the processes of channel development and evolution. Along its northern margin, Paine C consists of stacked, laterally offset channels, each eroded into fine‐grained mudstone and thin‐bedded sandy turbidites. Along its southern margin, the Paine C complex was bounded by a single, deeply incised but stepped erosional surface. The evolution of the Paine C channel occurred through multiple cycles of activity, each involving: (i) an initial period of channel erosion into underlying fine‐grained sediments; (ii) deposition of coarse‐grained pebble to cobble conglomerate and sandstone within the channel; and (iii) waning of coarse sediment deposition and accumulation of a widespread sheet of fine‐grained, thin‐bedded turbidites inside and outside the channel. The thin‐bedded turbidites deposited within, and adjacent to, the channel along the northern margin of the Paine C complex do not appear to represent levée deposits but, rather, a separate fine‐grained turbidite system that impinged on the Paine C channel from the north. The Cerro Toro channel complex in the Silla Syncline may mark either an early axial zone of the Magallanes Basin or a local slope mini‐basin developed behind a zone of slope faulting and folding now present immediately east of the syncline. If the latter, flows moving downslope toward the basin axis further east were diverted to the south by this developing structural high, deposited part of their coarse sediment loads, and exited the mini‐basin at a point located near the south‐eastern edge of the present Silla Syncline.
Stratigraphy and sedimentology of phosphate‐rich sediments in Malta and south‐eastern Sicily (latest Oligocene to early Late Miocene)
Authors: FÖLLMI K. B. , GERTSCH B. , RENEVEY J.‐P. , DE KAENEL E. , STILLE P.
Published: July 2008

The Maltese archipelago and south‐eastern Sicily include an Uppermost Oligocene to Upper Miocene hemipelagic sedimentary succession representing the Malta‐Hyblean plateau, which limits the eastern Mediterranean to the west. This succession hosts a unique and well‐exposed series of condensed and allochthonous phosphate‐rich beds, which were formed in a sedimentary regime of erosion, sediment reworking and frequent gravity‐flow deposition. The combination of nannofossil biostratigraphy and 87Sr/86Sr isotope stratigraphy allows for the precise attribution of ages to the phosphate deposits and for the distinction of three periods of major phosphogenesis. The first phase occurred between 24·5 and 21 Ma and 25 and 18·9 Ma (clustering of ages between 25 and 22·5 Ma) on Malta and Sicily, respectively. The second and third phases of phosphogenesis are documented from the Maltese Islands and are dated as 17·2 to 13·1 Ma and 10·9 to 9·8 Ma, respectively. The phosphate‐rich beds are associated with hiatuses and phases of important condensation which, for the oldest phosphogenic period, envelop the time period of 23·2 to 22 Ma for the Fomm Ir Rhi Bay section (Malta) and from 19·1 to 16·3 Ma for the sections of Sampieri and Modica (Sicily). For the second phase of phosphogenesis on the Maltese Islands, a consistent hiatus was found which embraces the time period of approximately 17 to 15 Ma. Also the third phase of phosphogenesis appears to be associated with a major hiatus, which probably envelops the time period between 12·5 and 10·9 Ma, but a better age control is needed here.

The correspondence in timing of the Maltese‐Sicilian phases of phosphogenesis with major phases of phosphogenesis outside the Mediterranean realm, to maxima in oceanic phosphorus‐burial rates and maxima in the δ13C benthic foraminiferal record suggests that the palaeoceanographic evolution of the eastern Mediterranean was well in phase with that of other ocean basins until at least the early Late Miocene, despite its increasing isolation due to the gradual closure of the Eurasian‐Arabian Strait and progressive sea‐level fall.
Petrography and temporal changes in petrofacies of deep‐marine Ainsa–Jaca basin sandstone systems, Early and Middle Eocene, Spanish Pyrenees
Authors: GUPTA KANCHAN DAS , PICKERING KEVIN T.
Published: July 2008

A petrographic study of 157 samples from the Early to Middle Eocene deep‐marine sandy systems, Ainsa–Jaca basin, Spanish Pyrenees, shows that each system has a characteristic petrofacies. Three main petrofacies are recognized. Petrofacies 1 sandstones comprise mainly siliciclastic grains (≥80%), subordinate terrigenous carbonate grains and negligible intrabasinal grains. Petrofacies 2 hybrid arenites are characterized by significant amounts (≥10%) of intrabasinal carbonate grains. Petrofacies 3 calcilithites contain relatively abundant (≥10%) extrabasinal carbonate grains. On the basis of these petrofacies, a revised correlation of the sandy systems is proposed between the more proximal Ainsa basin, and the more distal Jaca basin sediments, now separated by the Boltaña anticline, across which it is impossible to actually trace out individual beds or sandstone packages between both basins. The arenite composition in the Ainsa and Jaca basins is interpreted as being controlled mainly by synsedimentary tectonic processes that led to changes in sediment sources during basin evolution.
Trans‐specific gene silencing between host and parasitic plants
Authors: Tomilov Alexey A. , Tomilova Natalia B. , Wroblewski Tadeusz , Michelmore Richard , Yoder John I.
Published: July 2008

Species of Orobanchaceae parasitize the roots of nearby host plants to rob them of water and other nutrients. Parasitism can be debilitating to the host plant, and some of the world’s most pernicious agricultural pests are parasitic weeds. We demonstrate here that interfering hairpin constructs transformed into host plants can silence expression of the targeted genes in the parasite. Transgenic roots of the hemi‐parasitic plantTriphysaria versicolorexpressing the GUS reporter gene were allowed to parasitize transgenic lettuce roots expressing a hairpin RNA containing a fragment of the GUS gene (hpGUS). When stained for GUS activity,Triphysariaroots attached to non‐transgenic lettuce showed full GUS activity, but those parasitizing transgenic hpGUS lettuce lacked activity in root tissues distal to the haustorium. Transcript quantification indicated a reduction in the steady‐state level of GUS mRNA inTriphysariawhen they were attached to hpGUS lettuce. These results demonstrate that the GUS silencing signal generated by the host roots was translocated across the haustorium interface and was functional in the parasite. Movement across the haustorium was bi‐directional, as demonstrated in double‐junction experiments in which non‐transgenicTriphysariaconcomitantly parasitized two hosts, one transgenic for hpGUS and the other transgenic for a functional GUS gene. Observation of GUS silencing in the second host demonstrated that the silencing trigger could be moved from one host to another using the parasite as a physiological bridge. Silencing of parasite genes by generating siRNAs in the host provides a novel strategy for controlling parasitic weeds.