bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differential regulation of K+ channels in Arabidopsis epidermal and stelar root cells
Authors: DIATLOFF E. , GEIGER D. , SHANG L. , HEDRICH R. , ROBERTS S. K. 
Published: July 2004

ABSTRACTThe patch clamp technique was applied to protoplasts isolated from the epidermis and pericycle of Arabidopsis roots and their plasma membrane currents investigated. In the whole cell configuration, all protoplasts from the epidermis exhibited depolarization‐activated time‐dependent outwardly rectifying (OR) currents whereas OR currents were present in only 50% of cells from the pericycle. The properties of the OR currents in the epidermis and pericycle were compared with respect to their selectivity, pharmacology and gating. The time‐dependent activation kinetics, selectivity and sensitivity to extracellular tetraethyl ammonium of the OR current in each cell type were not significantly different. The reversal potential (Erev) of the OR currents indicated that they were primarily due to the movement of K+. However, the gating properties of the OR currents from the epidermis differed markedly from those exhibited in the pericycle. Although both cell types displayed OR currents with voltage‐dependent gating modulated in a potassium‐dependent fashion [i.e. the activation threshold (V0.5) was displaced to more positive voltages as extracellular K+ increased], the OR currents in the epidermis also displayed voltage‐independent gating by extracellular K+ which dramatically regulated current density. In the present study, reducing extracellular K+ activity from 40 to 0.87 mm reduced the OR current density in epidermal cells by approximately 80%. The chord conductance of the OR current saturated as a function of extracellular K+ and could be fitted with a Michaelis–Menten function to yield a binding constant (Km) of 10.5 mm. The ability of other monovalent cations to substitute for K+‐gating of the OR currents was also investigated and shown to exhibit a relative sequence of K+ ≥ Rb+ > Cs+ > Na+ ≥ Li+ (Eisenmann sequence IV) with respect to efficacy of gating. Furthermore, single channel recordings demonstrated that channel activity rather than the single channel conductance was modulated by extracellular K+. In contrast, OR current density in the pericycle was largely independent of extracellular K+. It is suggested that the contrasting gating properties of the K+ channels in the epidermis and pericycle reflect their different physiological roles, particularly with respect to their role in K+ (nutrient) transport from the soil solution to the shoot.
A root trait accounting for the extreme phosphorus sensitivity of Hakea prostrata (Proteaceae)
Authors: SHANE M. W. , SZOTA C. , LAMBERS H. 
Published: July 2004

ABSTRACTProteaceae are adapted to acquire P from nutrient‐impoverished soils; many function at very low leaf P levels, but are killed by P fertilization. Phosphorus toxicity develops at a remarkably low external P concentration. Previous studies have described P toxicity in Proteaceae, but the physiological basis for it remained unclear. The aim of the present study was to elucidate the physiological basis of P toxicity in Hakea prostrata R. Br. (Proteaceae). Triticum aestivum L. (Gramineae), Medicago truncatula Gaertn., Lupinus albus L. (both Fabaceae) and Hakea prostrata R.Br. were grown in solution at a range of P concentrations (0–1000 mmol P m−3), and determined net P‐uptake rates at 5 (all species) and 50 mmol P m−3 (H. prostrata only). With the exception of H. prostrata, net P‐uptake rates were fastest for plants grown without added P. Down‐regulation occurred for T. aestivum, M. truncatula and L. albus when the P concentration during growth was increased from 0 to 0.8 mmol P m−3, whereas in H. prostrata rates decreased only for plants grown at 10 mmol P m−3 or more. The leaf [P] at which P toxicity occurred in H. prostrata exceeded 10 mg g−1 dry matter, similar to that for crop species. The low capacity to reduce P uptake in response to increased supply offers a physiological explanation for the extreme sensitivity to P supply in H. prostrata, and possibly other Proteaceae.
New evidence for a role of vessel‐associated cells and phloem in the rapid xylem refilling of cavitated stems of Laurus nobilis L.
Authors: SALLEO S. , LO GULLO M. A. , TRIFILÒ P. , NARDINI A. 
Published: July 2004

ABSTRACTXylem recovery from embolism was studied in Laurus nobilis L. stems that were induced to cavitate by combining negative xylem pressure potentials (PX = −1.1 MPa) with positive air pressures (PC) applied using a pressure collar. Xylem refilling was measured by recording the percentage loss of hydraulic conductance (PLC) with respect to the maximum 2 min, 20 min and 15 h after pressure release. Sodium orthovanadate (an inhibitor of many ATP‐ases) strongly inhibited xylem refilling while fusicoccin (a stimulator of the plasma membrane H+‐ATPase) promoted complete embolism reversal. So, the refilling process was interpreted to result from energy‐dependent mechanisms. Stem girdling induced progressively larger inhibition to refilling the nearer to the embolized stem segment phloem was removed. The starch content of wood parenchyma was estimated as percentages of ray and vasicentric cells with high starch content with respect to the total, before and after stem embolism was induced. A closely linear positive relationship was found to exist between recovery from PLC and starch hydrolysis. This, was especially evident in vasicentric cells. A mechanism for xylem refilling based upon starch to sugar conversion and transport into embolized conduits, assisted by phloem pressure‐driven radial mass flow is proposed.
Locomotor Ability and Wariness in Yellow‐Bellied Marmots
Authors: Blumstein Daniel T. , Runyan Andrea , Seymour Mona , Nicodemus Amanda , Ozgul Arpat , Ransler Findley , Im Soyeon , Stark Tricia , Zugmeyer Claire , Daniel Janice C. 
Published: July 2004

AbstractAnimals employ a variety of behaviors to reduce or manage predation risk. Often, these are studied in isolation, but selection may act on packages of behavior that are referred to as behavioral syndromes. We focused on yellow‐bellied marmots (Marmota flaviventris) and examined three commonly studied antipredator behaviors. We fitted general linear models to explain variation in maximum running speed, time allocated to vigilance and foraging during bouts of foraging, and flight initiation distance (FID). Marmot maximum running speed was influenced by the substrate run across; marmots ran fastest across dirt or low vegetation and slowest across stones or talus. Incline and several other variables shown to affect running speed in other marmot species failed to explain significant variation in yellow‐bellied marmots. From these results we expected marmots to be sensitive to substrate while foraging, but insensitive to incline. However, time allocated to foraging was affected by incline but not by substrate. In bouts of foraging observed in different habitats, and on different inclines, more time was allocated to foraging and less to vigilance on steep slopes and less on level ground. Substrate influenced FID. Marmots in tall vegetation were less tolerant of an approaching person than were those in shorter vegetation. Finally, we found significant correlations between the residuals from the maximum running speed model and the residuals from the time allocated to vigilance and foraging models. We found a tendency for marmots that ran slower than predicted to be less vigilant while foraging. We also found that relatively slow marmots engaged in more active foraging and less vigilance during foraging bouts. This finding suggests a ‘locomotor ability‐wariness while foraging’ syndrome. It also suggests that vulnerable individuals minimize their exposure while foraging.
An Unusual Feature at the N‐terminal end of the Coat Protein of Maize dwarf mosaic virus isolated in Hungary
Authors: Tóbiás I. , Palkovics L. 
Published: July 2004

AbstractMaize dwarf mosaic is the most widespread virus disease affecting corn production in Hungary. In attempts to identify the causal virus by test plant reactions, enzyme‐linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR), only Maize dwarf mosaic virus (MDMV) was detected. To further characterize Hungarian isolates of MDMV, one isolate from each of the sweet corn varieties Dallas, Royalty and GH23‐85 was selected for sequence analysis of its coat protein (CP) gene. The three Hungarian isolates shared CP amino acid sequence similarities of 95–98% not only with one another but also with MDMV isolates from other countries. However, the N‐terminus of the CP of the ‘Dallas’ isolate was unusual in containing a stretch of 13 additional amino acids. This is the first report of variation in the size of the N‐terminus of the MDMV CP.
The Relationship between Branch Canker and Twig Dieback of Tea Caused by Macrophoma theicola
Authors: Thseng F. M. , Chen J. S. , Ko W. H. 
Published: July 2004

AbstractDuring a recent survey of the inoculum source of twig dieback of tea caused by Macrophoma theicola, symptoms of canker were observed on branches of a number of tea cultivars. Most cankered areas contained minute black pycnidia of M. theicola, which ooze white conidial masses in strands when incubated under moist conditions. Macrophoma theicola was also consistently isolated from cankered branches. When healthy branches of tea were inoculated with conidia of M. theicola obtained from diseased branches, cankers similar to those occurring in nature developed in the inoculated areas, and M. theicola was re‐isolated from all experimentally induced cankers. Isolates derived from conidia of M. theicola also caused dieback on healthy tea twigs, indicating that fruiting bodies on the cankered branches are the main inoculum source of twig dieback of tea. There was a positive correlation between the severity of twig dieback and the prevalence of branch canker among the tea cultivars surveyed. Six of the cultivars surveyed were highly resistant to M. theicola.
Spreading of ESFY Phytoplasmas in Stone Fruit in Catalonia (Spain)
Authors: Torres E. , Martín M. P. , Paltrinieri S. , Vila A. , Masalles R. , Bertaccini A. 
Published: July 2004

AbstractA survey was carried out in nine stone fruit commercial orchards located in Barcelona province where plum and apricot trees of different cultivars showing European stone fruit yellows (ESFY) symptoms were present. A 4‐year survey with visual inspection of symptoms in one apricot orchard showed a rather high ESFY disease spread, also in a Japanese plum plantation newly infected plants were detected every year in a similar rate (about 2%). All the inspected symptomatic trees were polymerase chain reaction (PCR) tested and ESFY phytoplasma identity was confirmed by restriction fragment length polymorphism analyses and sequencing of ribosomal DNA amplification products. In apricot plantation the detection of ESFY phytoplasma was also tested on 69 asymptomatic trees sampled in summer 2002. The nested PCR with 16SrX group‐specific primers allowed detection of ESFY phytoplasmas in 50% of the trees that indeed showed symptoms by the next winter (2003). The molecular detection of ESFY phytoplasma in asymptomatic apricot trees indicates the risk of maintaining phytoplasma foci in the fields where eradication is based only on visual inspection.
Partial Molecular Characterization of a Czech Isolate of Grapevine leafroll‐associated virus 3
Authors: Komínek P. , Bryxiová M. , Glasa M. 
Published: July 2004

Abstract Grapevine leafroll‐associated virus 3 (GLRaV‐3) is an important pathogen of grapevine in the Czech Republic. A Czech isolate was studied at the molecular level in order to extend data on molecular variability of the virus from the central European region. Three conserved regions (genes encoding the RNA‐dependent RNA polymerase, the heat shock protein 70 and the 55 kDa protein) were amplified using reverse transcriptase‐polymerase chain reaction, sequenced and compared with related available sequences. On the sequenced regions, the Czech isolate revealed more than 99% nucleotide and amino acid identity with the published full‐length sequence of a North American GLRaV‐3 isolate and a similarly high identity with available partial GLRaV‐3 sequences of isolates from different parts of the world. The phylogenetic position of the new and already characterized GLRaV‐3 isolates within the Ampelovirus genus is discussed.
The Enlightenment Function and Dimensions of Time: Evolutionary Theory and Limits of Privatisation in British Trunk Roads Policy
Authors: Dudley Geoffrey 
Published: July 2004

The evolutionary model provides important insights into the causal mechanisms of policy change. This works particularly through the notion that the introduction and success or failure of new ideas is a key element in instigating these policy change processes. The survival of an idea is also dependent on key temporal and spatial factors. An idea therefore urgently requires a method of propagation in order to reproduce itself. One means of this idea transmission is through the ‘enlightenment function’, whereby an effective policy network may gradually alter the assumptions and idea ‘images' of policy makers over time. For example, the interrelationships between ideas, established epistemic communities and time emerge as key variables in determining the enlightenment function in implementation arenas. Time emerges as a vital multi-dimensional independent variable, and in one crucial dimension approximates with a state of readiness as outlined in Vickers' appreciative system. The article employs the case study of the limits of the privatisation idea in British trunk roads policy, and concludes that, even in seeking stability, actors tend to generate unpredictable change.
Rebel Colours: ‘Framing’ in Global Social Movements
Authors: Chesters Graeme , Welsh Ian 
Published: July 2004

This paper presents data gathered during and since the protests against the IMF and World Bank meetings in Prague in September 2000. It describes the interactional and deliberative processes that were undertaken by activists involved in framing the protests and the manifestation of this ‘frame-work’ in three separate marches denoted by different colours, which took place on September 26th during a ‘global day of action’. The paper utilises ethnographic detail to develop a critically engaged model of social movement frame analysis that focuses upon the genesis of these ‘action frames’, including the elaborate negotiation of conflicting ideological and tactical dispositions that lay behind them, and the variety of democratic decision making forums which were instrumental in their design.
Risks for the Long Run: A Potential Resolution of Asset Pricing Puzzles
Authors: Bansal Ravi , Yaron Amir 
Published: July 2004

ABSTRACTWe model consumption and dividend growth rates as containing (1) a small long‐run predictable component, and (2) fluctuating economic uncertainty (consumption volatility). These dynamics, for which we provide empirical support, in conjunction with Epstein and Zin's (1989) preferences, can explain key asset markets phenomena. In our economy, financial markets dislike economic uncertainty and better long‐run growth prospects raise equity prices. The model can justify the equity premium, the risk‐free rate, and the volatility of the market return, risk‐free rate, and the price–dividend ratio. As in the data, dividend yields predict returns and the volatility of returns is time‐varying.
The Nature of Discipline by Corporate Takeovers
Authors: Kini Omesh , Kracaw William , Mian Shehzad 
Published: July 2004

ABSTRACTThis paper provides a comprehensive examination of the disciplinary role of the corporate takeover market using a sample of U.S. target firms over the period 1979 to 1998. The time period spanned allows a broader study not only of the disciplinary role of the takeover market in general, but also of the interaction between the takeover market and alternative governance mechanisms during the 1980s and 1990s. Overall, our evidence is consistent with the view of the corporate takeover market as a “court of last resort,” that is, it is an external source of discipline that intercedes when internal control mechanisms are relatively weak or ineffective.
Employee Stock Options, Corporate Taxes, and Debt Policy
Authors: Graham John R. , Lang Mark H. , Shackelford Douglas A. 
Published: July 2004

ABSTRACTWe find that employee stock option deductions lead to large aggregate tax savings for Nasdaq 100 and S&P 100 firms and also affect corporate marginal tax rates. For Nasdaq firms, including the effect of options reduces the estimated median marginal tax rate from 31% to 5%. For S&P firms, in contrast, option deductions do not affect marginal tax rates to a large degree. Our evidence suggests that option deductions are important nondebt tax shields and that option deductions substitute for interest deductions in corporate capital structure decisions, explaining in part why some firms use so little debt.
Improving the Acceptability of the Atrial Defibrillator:
Authors: BOODHOO LANA , MITCHELL ANDREW , UJHELYI MICHAEL , SULKE NEIL 
Published: July 2004

Acceptability of the atrial defibrillator is partly limited by concerns about shock related anxiety and discomfort. Sedation and/or automatic cardioversion therapy during sleep may ease shock discomfort and improve patient acceptability. Three atrial cardioversion techniques were compared: patient‐activated cardioversion with sedation, automatic night cardioversion with sedation, and automatic night cardioversion without sedation. Sedation was oral midazolam (15 mg). Fifteen patients aged 60 ± 13 years were assigned each strategy randomly for three consecutive episodes of persistent atrial fibrillation requiring cardioversion. Patients completed questionnaires for multiple parameters immediately and again at 24 hours postcardioversion. Atrial cardioversion strategies with oral sedation (patient‐activated and automatic) significantly reduced shock recall by 77% (P < 0.005), therapy dissatisfaction by 57%‐71% (P < 0.03), shock discomfort by 61%‐73% (P < 0.01), shock pain by 79%‐83% (P < 0.001), and shock intensity by 73%‐77% (P < 0.03), compared to automatic night cardioversion without sedation (P < 0.02). Atrial shock pain was short‐lived and caused little disruption to the patients' daily routines. Automatic night cardioversion without sedation, resulted in sleep disturbances not seen with the other strategies (42% vs 0%, P < 0.001) as well as concerns about future pain or discomfort. Twelve patients (80%) chose patient‐activated cardioversion with sedation as their preferred treatment, and three (20%) remainder chose automatic night cardioversion with sedation. Ninety percent of patients chose automatic night cardioversion without sedation as the least acceptable therapy. Sedation significantly increases atrial shock acceptability regardless of cardioversion method. Shocks without sedation are significantly less acceptable to patients using the atrial defibrillators. (PACE 2004; 27:910–917)
High Incidence of Appropriate and Inappropriate ICD Therapies in Children and Adolescents with Implantable Cardioverter Defibrillator
Authors: KORTE THOMAS , KÖDITZ HARALD , NIEHAUS MICHAEL , PAUL THOMAS , TEBBENJOHANNS JÜRGEN 
Published: July 2004

Appropriate and inappropriate therapies of implantable cardioverter defibrillators have a major impact on morbidity and quality of life in ICD recipients, but have not been systematically studied in children and young adults during long‐term follow‐up. ICD implantation was performed in 20 patients at the mean age of 16 ± 6 years, 11 of which had prior surgical repair of a congenital heart defect, 9 patients had other cardiac diseases. Implant indications were aborted sudden cardiac death in six patients, recurrent ventricular tachycardia in 9 patient, and syncope in 5 patients. Epicardial implantation was performed in 6 and transvenous implantation in 14 patients. Incidence, reasons and predictors (age, gender, repaired congenital heart disease, history of supraventricular tachycardia, and epicardial electrode system) of appropriate and inappropriate ICD therapies were analyzed during a mean follow‐up period of 51 ± 31 months range 18‐132 months. There were a total 239 ICD therapies in 17 patients (85%) with a therapy rate of 2.8 per patient‐years of follow‐up. 127 (53%) ICD therapies in 15 (75%) patients were catagorized as appropriate and 112 (47%) therapies in 10 (50%) patients as inappropriate, with a rate of 1.5 appropriate and 1.3 inappropriate ICD therapies per patient‐years of follow‐up. Time to first appropriate therapy was 16 ± 18 months. Appropriate therapies were caused by ventricular fibrillation in 29 and ventricular tachycardia in 98 episodes. Termination was successful by antitachycardia pacing in 4 (3%) and by shock therapy in 123 episodes (97%). Time to first inappropriate therapy was 16 ± 17 months. Inappropriate therapies were caused by supraventricular tachycardia in 77 (69%), T wave oversensing in 19 (17%), and electrode defect in 16 episodes (14%). It caused shocks in 87 (78%) and only antitachycardia pacing in 25 episodes (22%). No clinical variable could be identified as predictor of either appropriate or inappropriate ICD therapies. There is a high rate of ICD therapies in young ICD recipients, the majority of which occur during early follow‐up. The rate of inappropriate therapies is as high as 47% and is caused by supraventricular tachycardia and electrode complications in the majority of cases. Prospective trials are required to establish preventative startegies of ICD therapies in this young patient population. (PACE 2004; 27:924–932)
Keeping a good heart: The experience of Japanese elders in a health‐care facility for the elderly
Authors: HAMAHATA Akiko , MAGILVY Kathy , HOSHINO Junko , KOMATSU Misa 
Published: July 2004

AbstractAim:  To clarify the experience of elderly people admitted to a health‐care facility for the elderly.Methods:  An ethnographic approach and qualitative descriptive design was used to understand and describe the viewpoints of the elderly living in a health‐care facility. A semistructured interview was conducted in the resident's room. One at a time, the transcript of each participant's interview was read repeatedly and the parts corresponding to the participant's experience were extracted and analysed qualitatively.Results:  The participants were seven elderly residents of a health‐care facility for the elderly who were over 65 years of age and able to converse. The current experience of the seven elderly participants were divided into seven categories based upon the qualitative descriptive analysis: family ties, emotional response to entering the facility, rehabilitation to support independence, principles for living and getting along with others, life after leaving the facility, relationships with facility staff, and memories. An over‐arching theme was also identified, ‘keeping a good heart’ described as following the category descriptions.Conclusions:  Keeping a good heart symbolized the resilience and positive acceptance of life in the health‐care facility for the elderly.