bluuebunny/crossref_metadata_2025_split huggingface dataset:
Late Pleistocene and early Holocene rivers and wetlands in the Bonneville basin of western North America
Authors: Oviatt Charles G. , Madsen David B. , Schmitt Dave N. 
Published: August 2003

AbstractField investigations at Dugway Proving Ground in western Utah have produced new data on the chronology and human occupation of late Pleistocene and early Holocene lakes, rivers, and wetlands in the Lake Bonneville basin. We have classified paleo-river channels of these ages as “gravel channels” and “sand channels.” Gravel channels are straight to curved, digitate, and have abrupt bulbous ends. They are composed of fine gravel and coarse sand, and are topographically inverted (i.e., they stand higher than the surrounding mudflats). Sand channels are younger and sand filled, with well-developed meander-scroll morphology that is truncated by deflated mudflat surfaces. Gravel channels were formed by a river that originated as overflow from the Sevier basin along the Old River Bed during the late regressive phases of Lake Bonneville (after 12,500 and prior to 11,000 14C yr B.P.). Dated samples from sand channels and associated fluvial overbank and wetland deposits range in age from 11,000 to 8800 14C yr B.P., and are probably related to continued Sevier-basin overflow and to groundwater discharge. Paleoarchaic foragers occupied numerous sites on gravel-channel landforms and adjacent to sand channels in the extensive early Holocene wetland habitats. Reworking of tools and limited toolstone diversity is consistent with theoretical models suggesting Paleoarchaic foragers in the Old River Bed delta were less mobile than elsewhere in the Great Basin.
A Rhizocarpon geographicum growth curve for the Cascade Range of Washington and northern Oregon, USA
Authors: O'Neal Michael A , Schoenenberger Katherine R 
Published: August 2003

AbstractLichen thallus measurements from 22 surfaces of known age on Mount Baker, Mount Hood, and Mount Rainier are used to construct a regional Rhizocarpon geographicum growth curve for the Cascade Range of Washington and northern Oregon. Growth rates determined by measuring the largest thallus diameters on the same surfaces at Mount Rainier in 1976 and 2002 are used for comparison with lichenometric data from Mount Baker and Mount Hood. Similar lichen thallus diameter vs age relationships identified in the data from the three mountains suggest the presence of uniform growth rates over the 400-km range. A regional growth curve developed during our study shows three growth phases of successively slower growth: a rapid phase from 8 to 20 yr, a linear phase from 20 to 145 yr, and a slow phase of unknown duration beyond ca. 145 yr. Uncertainty in lichen growth rates beyond 145 yr limits projection of the curve beyond that age; however, the age range of the constrained growth curve covers an important period of recent climate variability. When applied in appropriate settings, our growth curve can be used to determine numeric ages to ±10 yr for surfaces between 20 and 145 years old in areas where other techniques are not applicable or do not provide unique or well-constrained ages.
Exploring views on Swedish district nurses' prescribing – a focus group study in primary health care
Authors: Wilhelmsson Susan , Foldevi Mats 
Published: August 2003

Summary• Since 1994 district nurses (DNs) in Sweden have been permitted to prescribe drugs from a limited list. This reform has met severe resistance from doctors and the opinions of general practitioners (GPs) and DNs have differed in many aspects.• The aim of this study was to gain deeper understanding of the different opinions about DNs' prescribing and to explore the impact of the reform on primary care.• Six focus group interviews were conducted, four with DNs and two with GPs.• Data analysis revealed six categories, which were condensed into two dimensions. The dimensions were individual prerequisites, with the categories responsibility and knowledge, and organizational prerequisites, with the categories distribution of work, climate of co‐operation, resistance and economic considerations.• District nurses were very positive towards prescribing and had gained new knowledge through the compulsory training course and via discussions with pharmacists. Because of the responsibility required for prescribing, some nurses had introduced systems for self‐monitoring. Prescribing was seen as a natural part of the nursing process. All interviewees could describe periods of resistance against the reform, and the head of the health centre was a key person for attitudes at the workplace.• The DNs found the nurse prescribing reform very positive. They experienced a strengthening of professionalism and also thought that the reform was a natural development. Negative attitudes and opinions offset the positive feelings. The resistance that had appeared in the beginning had now turned into silent acceptance.
Seeing the person behind the patient: enhancing the care of older people using a biographical approach
Authors: Clarke Amanda , Jane Hanson Elizabeth , Ross Helen 
Published: August 2003

Summary• Recent policy statements have stressed the need for fundamental changes to the NHS, especially to the hospital care of older people. Person‐centred care underpins such changes. If practitioners are to deliver person‐centred care, then they need to learn more about the patient as an individual. One way that this might be achieved is through biographical approaches.• This paper describes the findings of a developmental study undertaken over a 6‐month period to investigate the introduction of a biographical approach to care on a unit in a NHS hospital. It concentrates on the views of the practitioners who used the approach.• The study aimed to explore whether a biographical approach – in the form of storytelling – might be used to encourage person‐centred practice.• Using a practice development approach, the study explored the views of older people, their family carers and practitioners regarding their participation in life story work.• Initial data were collected by focus groups with staff from a nursing home who regularly used life stories as a basis for care planning. Further data were collected through focus groups, semistructured interviews and observation – undertaken before and after the introduction of life story work – with older people, family carers and practitioners.• Findings revealed that life stories helped practitioners to see patients as people, to understand individuals more fully and to form closer relationships with their families. Support workers also said how much they enjoyed using the approach to inform their care.• Further longitudinal research is required to investigate biographical approaches more fully and to work more closely with practitioners to explore how biographical approaches can be undertaken as part of standard practice and be integrated into the culture and management of care.
Nurse practitioner–client interaction as resource exchange in a women's health clinic: an exploratory study
Authors: Donohue Rebecca K. 
Published: August 2003

Summary• Empirical research has thoroughly documented the success of nurse practitioners (NPs) in terms of patient satisfaction and cost‐effectiveness. What is missing is the in‐depth knowledge of the interactive process through which this is accomplished during a clinic visit.• The aim of this study was to understand the special nature and processes of NP and client encounters in the ambulatory primary care context using a resource exchange perspective.• An exploratory descriptive design was used to address the following research questions: (i) What do midlife female clients expect in terms of resources to be exchanged prior to a visit with a NP in an ambulatory clinic visit? (ii) What resources are actually exchanged during the clinic visit? (iii) To what extent is there congruence between a woman's expectations and what she is actually receiving from the clinic visit in terms of resources exchanged?• The participants included two women health NPs and eight midlife female clients.• Data for the study were comprised of audiotaped pre‐ and postencounter interviews with the clients, audiotapes of the entire clinic visits with the NP and field notes recorded by the researcher of the client visits. Content analysis was conducted using ETHNOGRAPH software.• Findings indicated that clients of both NPs had surprisingly similar expectations of receipt of services as well as actual receipt of services. Resources expected and received from the visits included some combination of services, health information, trust, self‐disclosure, support, affirmation, time, acceptance and respect.• Results of this study suggest that resource exchange theoretical formulations can be applied to NP–client interactions to understand and explain the specific nature of resources the clients expect and receive from a NP during a woman's health clinic visit.
Repression of the Ac‐transposase gene promoter by Ac transposase
Authors: Fridlender Marcelo , Harrison Kate , Jones Jonathan D.G. , Levy Avraham A. 
Published: August 2003

SummaryMobility of the maize Ac‐Ds transposable element family depends on the production of Ac‐encoded transposase (TPASE). The TPASE is a DNA‐binding protein which recognizes internal sites near both Ac termini in a region which overlaps the putative TPASE gene promoter. Therefore, it was hypothesized that TPASE may regulate its own transcription. The TPASE effect on Ac promoter activity was tested in transgenic tobacco plants and in protoplasts transformed with Ac‐promoter‐β‐glucuronidase gene fusions. It was found that TPASE can repress Ac promoter activity in cotyledons and leaves of transgenic plants, as well as in transient assays in protoplasts. TPASE‐mediated repression occurs independently of the presence of the Ac untranslated leader or of the 3′ termini. When fused to a deleted (−67) cauliflower mosaic virus 35S promoter, the first 237 bp of Ac (starting from the 5′ end) are sufficient to enable TPASE‐mediated repression. The results indicate that TPASE can act as a transcriptional repressor. The possible mechanisms and significance of TPASE‐mediated repression are discussed.
Design in Arabidopsis thaliana of a synchronous system of floral induction by one long day
Authors: Corbesier Laurent , Gadisseur Isabelle , Silvestre Georges , Jacqmard Annie , Bernier Georges 
Published: August 2003

SummaryA system of one‐shot induction of flowering in Arabidopsis thaliana, ecotype Columbia, is described. Plants from vernalized seeds are grown for 2 months in 8 h short days at an irradiance of 48 µmol m−2 sec−1 (fluorescent light only). At that age they can be induced to flower by exposure to either a single long day or a single displaced short day. Non‐induced plants stay vegetative for at least a further month. Synchrony of induction among the individuals of the population exposed to one long day is of the same order as in the best classical model plants, that is, the fastest individuals are only 6 h ahead of the slowest ones. A further advantage of this system is the large size of plants at the time of induction, allowing easy analysis of changes in leaves, leaf exudate and shoot meristem. The design of such a synchronous system will allow the timings of gene activations and deactivations to be established in the different plant parts, before flowers are initiated.
Electroanatomic Analysis of Sinus Impulse Propagation in Normal Human Atria
Authors: DE PONTI ROBERTO , HO SIEW YEN , SALERNO‐URIARTE JORGE A. , TRITTO MASSIMO , SPADACINI GIAMMARIO 
Published: August 2003

Sinus Impulse Propagation in Normal Human Atria.
Introduction: Better understanding of atrial propagation during sinus rhythm (SR) in normal hearts under the most normal physiologic conditions may be propaedeutic to pathophysiologic studies of complex atrial arrhythmias. In this study, qualitative and quantitative analyses of sinus impulse propagation in both atria were performed by electroanatomic mapping in patients with no organic heart disease who were undergoing an electrophysiologic procedure. Methods and Results: Seven patients (5 men and 2 women; age 37 ± 11 years) undergoing ablation of a left‐sided accessory pathway were considered. Associated heart disease and coexisting atrial arrhythmias were excluded. After obtaining informed consent, electroanatomic mapping of both atria was performed during SR using a nonfluoroscopic system in the postablation phase. Mapping was accomplished in all patients with no complications. Qualitative analysis showed that sinus impulse propagation gives a reproducible activation pattern with minor individual variations. During interatrial propagation, two breakthroughs (anterior and posterior) in the left atrium are observed in the majority of cases. The anterior breakthrough, which reflects conduction over Bachmann's bundle, is predominant and shows a peculiar “preexcitation‐like” endocardial activation pattern. Quantitative analysis showed minimal individual variations of propagation time intervals. Atria are activated simultaneously for 65% ± 9% of the duration of the atrial systolic time interval. Conclusion: In normal humans, electroanatomic mapping of SR identifies a typical and reproducible propagation pattern during SR. Bachmann's bundle plays the most important role in interatrial propagation. Atria are activated simultaneously by sinus impulse for a relevant portion of the systolic time interval.
Pulmonary Vein Isolation: Comparison of Bipolar and Unipolar Electrograms at Successful and Unsuccessful Ostial Ablation Sites
Authors: TADA HIROSHI , ORAL HAKAN , WASMER KRISTINA , GREENSTEIN RADMIRA , PELOSI FRANK , KNIGHT BRADLEY P. , STRICKBERGER S. ADAM , MORADY FRED 
Published: August 2003

Electrogram Analysis.
Introduction: No prior studies have quantitatively analyzed the characteristics of bipolar or unipolar electrograms that may be helpful in identifying successful ostial ablation sites in patients with atrial fibrillation undergoing segmental pulmonary vein isolation. Methods and Results: The characteristics of bipolar and unipolar electrograms recorded at 185 successful and 120 unsuccessful ostial pulmonary venous ablation sites were analyzed in 21 patients with atrial fibrillation. A decapolar Lasso catheter was positioned near the ostia of the pulmonary veins, and a conventional ablation catheter was used to deliver radiofrequency energy at individual ostial sites where pulmonary vein potentials were recorded. With both bipolar and unipolar recordings, the only timing parameter that distinguished successful from unsuccessful ostial ablation sites was the timing of the electrogram recorded by the ablation catheter relative to the earliest pulmonary vein potential recorded by the Lasso catheter. With both bipolar and unipolar recordings, electrograms demonstrated a larger amplitude at successful than at unsuccessful ablation sites. Unipolar electrograms had a steeper intrinsic deflection at successful than at unsuccessful ostial ablation sites. The morphologies of the unipolar electrograms recorded by the ablation catheter and by the contiguous electrode of the Lasso catheter usually were identical. Conclusion: In patients undergoing segmental isolation of the pulmonary veins, unipolar recordings provide more information than bipolar recordings helpful in distinguishing successful from unsuccessful ostial ablation sites. Furthermore, unipolar recordings, but not bipolar recordings, allow accurate localization of the position of the ablation catheter relative to the electrodes of the Lasso catheter.
Accelerated Inactivation of Voltage‐Dependent K+ Outward Current in Cardiomyocytes from Thyroid Hormone Receptor α1‐Deficient Mice
Authors: JOHANSSON CATARINA , KOOPMANN ROLF , VENNSTRÖM BJÖRN , BENNDORF KLAUS 
Published: August 2003

Voltage‐Dependent K+ Outward Current in TRα1‐Deficient Mice.
Introduction: Thyroid hormone affects the electrophysiologic properties of the heart. It is not known which of the different subtypes of thyroid hormone receptors mediate these effects. Methods and Results: Using standard patch‐clamp techniques, we studied time‐ and voltage‐dependent properties of depolarization‐activated K+ currents in ventricular heart cells isolated from mice lacking the thyroid hormone receptor α1 (TRα1) and compared these currents with those in respective wild‐type cells. In both groups of cells, the time course of current decay could be described by two inactivating exponential components and a sustained current component. In TRα1‐deficient cells, the total inactivation time course was accelerated due to both increase of the relative contribution of the fast component and shortening of the slow time constant. The peak amplitude of the total current was not altered. The main component of steady‐state inactivation of the voltage‐dependent K+ outward current was shifted to more hyperpolarized voltages by 7 mV in TRα1‐deficient cells compared with that in wild‐type cells. Under current‐clamp conditions, action potential duration at 90% repolarization was prolonged in TRα1‐deficient cells compared with that in wild‐type cells by 3.6 msec. Conclusion: The resulting acceleration of the total inactivation time course is proposed to contribute to action potential prolongation and thus to the increased QTend‐time observed previously on ECG of TRα1‐deficient mice.
Novel Electrophysiologic Parameter of Dispersion of Atrial Repolarization: Comparison of Different Atrial Pacing Methods
Authors: OGAWA MASAHIRO , KUMAGAI KOICHIRO , GONDO NAOKI , MATSUMOTO NAOMICHI , SUYAMA KAZUHIRO , SAKU KEIJIRO 
Published: August 2003

Novel Parameter of Dispersion of Atrial Repolarization.
Introduction: Heterogeneity of ventricular repolarization plays a major role in reentrant tachyarrhythmias in cardiac tissue. However, the role of atrial repolarization added activation time (AT) to refractoriness in atrial vulnerability has not been investigated in detail. Methods and Results: The study population consisted of 34 patients: 18 with atrial fibrillation (AF) and 16 without AF (control group). The effective refractory periods (ERPs) in the right atrial appendage, low lateral right atrium, high right septum, and distal coronary sinus, and ATs from P wave onset to each electrogram during sinus rhythm and right atrial appendage, low lateral right atrial, high right septal, distal coronary sinus, and biatrial pacing were measured. Atrial recovery time, defined as the sum of AT and ERP, and its dispersions during sinus rhythm, right atrial appendage, low lateral right atrial, high right septal, distal coronary sinus, and biatrial pacing were calculated. Both ERP dispersion and atrial recovery time dispersion during sinus rhythm were significantly greater in the AF group than in the control group. Atrial recovery time dispersion during distal coronary sinus, high right septal, or biatrial pacing was significantly smaller than that during right atrial appendage or low lateral right atrial pacing in each group. In particular, atrial recovery time dispersion during distal coronary sinus pacing was the smallest of the five pacing methods in the AF group. P wave duration during biatrial or high right septal pacing was significantly shorter than during right atrial appendage, low lateral right atrial, or distal coronary sinus pacing in each group. Conclusion: Atrial recovery time dispersion is suitable as an electrophysiologic parameter of atrial vulnerability. Distal coronary sinus pacing may prevent AF by increasing homogeneity of atrial repolarization, whereas biatrial and high right septal pacing contribute not only homogeneity of atrial repolarization but also improvement of atrial depolarization.
Sustained Monomorphic Ventricular Tachycardia Ablation from the Aortic Sinus of Valsalva
Authors: LI YI‐GANG , GRÖNEFELD GERIAN , ISRAEL CARSTEN , HOHNLOSER STEFAN H. 
Published: August 2003

Ablation of Monomorphic VT from the Aortic Sinus.
Introduction: The aim of this study was to delineate the electrophysiologic mechanisms of a novel type of ventricular tachycardia (VT) originating from the aortic sinus of Valsalva. Methods and Results: Endocardial mapping was performed in four patients with symptomatic VT originating from the aortic sinus of Valsalva. Two patients suffered from dilative cardiomyopathy; the other two patients had no structural heart disease. Five VTs could be induced and terminated by programmed ventricular stimulation. Successful ablation was performed in the noncoronary sinus of Valsalva in three VTs and in the left aortic sinus in two. Abnormal (diastolic or presystolic) potentials were recorded during sinus rhythm (mean interval from the end of QRS complex to the potential 121 ± 98 msec) and during VT (mean interval from the potential to QRS complex 64 ± 45 msec) at effective sites in the aortic sinuses of Valsalva. Concealed entrainment was demonstrated at all successful sites. VT recurred in one patient after 1 month, whereas no recurrences were observed during follow‐up of 8 ± 6 months in the other three patients. Conclusion: Reentry constitutes one mechanism of VT originating from the aortic sinus of Valsalva. Entrainment mapping is useful to characterize the reentrant circuit of these VTs and to guide ablation.
Clinical Evaluation of a Policy of Early Repeated Internal Cardioversion for Recurrence of Atrial Fibrillation
Authors: FYNN SIMON P. , TODD DERICK M. , HOBBS W. JULIAN C. , ARMSTRONG KAREN L. , FITZPATRICK ADAM P. , GARRATT CLIFFORD J. 
Published: August 2003

Early Repeated Cardioversion for AF Recurrence.
Introduction: The clinical value of cardioversion (CV) of persistent atrial fibrillation (AF) is limited by the high rate of early AF recurrence, which may be related to the persistence of atrial electrical remodeling. We examined the hypothesis that the likelihood of maintaining sinus rhythm after CV of persistent AF is significantly enhanced by a policy of early repeated CV. Methods and Results: Fifty‐nine patients with persistent AF underwent internal CV (CV 1). Those patients cardioverted were monitored with daily transtelephonic ECG. In the event of AF recurrence, these patients were admitted rapidly for repeat CV (CV 2) and, if further recurrence occurred, a third CV (CV 3) was performed. Daily ECG monitoring was continued until 1 month of sinus rhythm was maintained or a total of three CVs were performed. Of the 59 patients undergoing CV 1, 43 were discharged in sinus rhythm and 29 subsequently had AF recurrence during monitoring. Twenty‐three of these underwent CV 2 and 11 of these underwent CV 3. Of those having repeated CVs, only 4 patients maintained sinus rhythm for 1 month (3 after CV 2 and 1 after CV 3). The remaining patients had repeated AF recurrence during the monitoring period. Mean time from AF recurrence to CV 2 was 20 ± 13 hours and from AF recurrence to CV 3 was 13 ± 7.2 hours. Atrial effective refractory periods increased from 189 ± 16 msec at CV 1 to 215 ± 18 msec at CV 3 (P < 0.05), indicating reversal of atrial electrical remodeling during this period. Conclusion: A policy of early repeated CVs for AF recurrence has very limited clinical value despite evidence of reversal of atrial electrical remodeling. The time between AF recurrence and repeat CV may need to be reduced further if such a policy is to succeed.