bluuebunny/crossref_metadata_2025_split huggingface dataset:
A systemic approach to entrepreneurial learning: an exploration using storytelling
Authors: Warren Lorraine 
Published: January 2004

AbstractThe promotion of entrepreneurial activity is high on the educational agenda, reflecting economic and political interest and support. However, the study of entrepreneurial learning is characterized by a diffuse and fragmented literature which spans policy, individual learning and business development, with conclusions based on a plethora of methodological approaches. In this paper, a systemic schema is modified and developed to provide a frame of reference for the study of entrepreneurial learning. The paper is based on a study of women's narratives of their experience as small/micro‐enterprise owner/managers in the UK. Theoretical developments concerning the potential usefulness of the schema are discussed; practical implications for the design of entrepreneurship development programmes are also presented. Copyright © 2004 John Wiley & Sons, Ltd.
Systems thinking and knowledge management: positional assertions and preliminary observations
Authors: Kawalek J. P. 
Published: January 2004

AbstractIn recent years, there has been significant interest in [knowledge management]. However, the plethora of both conceptual and practitioner literature has provided little consistency regarding key definitions or methodologies that can act to guide practice. This can result in practitioners selecting particular ideas, constructs or language that has weak conceptual grounding and result in ephemeral and [ad hoc] practices. This paper analyses the use of systems thinking for [knowledge management] practices because it is argued to have the potential to provide methodological guidance for practitioners. The context of the research in the paper is in the humanitarian sector, and in operations that are often politically messy and complex, where there are often many unknown factors. It is a context in which knowledge in a broad sense of the word, as in any human activity, plays an instrumental role. Copyright © 2004 John Wiley & Sons, Ltd.
The problem of knowledge imposition: Paulo Freire and critical systems thinking
Authors: Mejía Andrés 
Published: January 2004

AbstractTwo different ways can be distinguished in which the problem of imposition of knowledge has been addressed by Paulo Freire's radical educational proposal: (1) through an examination of formal aspects of the interactions in which knowledge is produced and/or reproduced—the problem of interactions—and (2) through the provision of critical tools with which the validity of any proposed knowledge can be questioned—the problem of validity. In that proposal, these strategies appear represented by Freire's notions of dialogue—on the side of interactions—and critical consciousness—on the side of validity. There appears, however, a tension between them, as the critical tools provided to question validity and develop a critical consciousness might go against the beliefs held by the students whose reasoning autonomy is to be developed, making it necessary to manipulate interactions and therefore promote a non‐genuine dialogue. In critical systems thinking, the ways in which knowledge imposition occurs or is prevented through the use of both boundary critique—represented in Ulrich's CSH—and critical pluralism—represented in Jackson's TSI—are analysed in relation to the use of the same or similar strategies to those found in Freire's work, and to the tension between them. Copyright © 2004 John Wiley & Sons, Ltd.
Where is ENSO stress balanced?
Authors: Münnich Matthias , Neelin J. David 
Published: January 2004

AbstractThe zonal surface torque budget associated with the tropical wind stress anomalies during El Niño/Southern Oscillation is analyzed. Mountain and surface stress torques over South America are found to play a prominent role. Local momentum change is negligible for 6 month averages allowing the balance among regional contributions to the torque anomalies to be compared. During El Niño, eastward torque anomalies over the central equatorial Pacific are largely compensated by westward anomalies elsewhere in the equatorial band, notably over South America. Torque anomalies over South America and the Pacific in latitude bands north and south of the equator are both westward and are not compensated within the band, implying an export of eastward momentum to higher latitudes. Copyright © 2003 Royal Meteorological Society. Published by Elsevier Ltd. All rights reserved.
Searching for circulation patterns affecting North Europe annual temperature
Authors: Kryjov Vladimir N. 
Published: January 2004

AbstractStatistical analysis of Northern Europe annual temperature against monthly pressure fields reveals that the circulation modes resembling North Atlantic/Arctic Oscillation significantly contribute to annual temperature only in January and February. In November, significant contribution is associated with the Labrador–Scandinavia teleconnection pattern. The January–February and November circulation modes are significantly (negatively) correlated with each other. Copyright © 2003 Royal Meteorological Society. Published by Elsevier Ltd. All rights reserved.
N‐acetyl‐GLP‐1: a DPP IV‐resistant analogue of glucagon‐like peptide‐1 (GLP‐1) with improved effects on pancreatic β‐cell‐associated gene expression
Authors: Liu Hui‐Kang , Green Brian D. , Gault Victor A. , McCluskey Jane T. , McClenaghan Neville H. , O'Harte P. M. Finbarr , Flatt Peter R. 
Published: January 2004

AbstractGlucagon‐like peptide‐1(7‐36)amide (GLP‐1) is a key insulinotropic hormone with the reported potential to differentiate non‐insulin secreting cells into insulin‐secreting cells. The short biological half‐life of GLP‐1 after cleavage by dipeptidylpeptidase IV (DPP IV) to GLP‐1(9‐36)amide is a major therapeutic drawback. Several GLP‐1 analogues have been developed with improved stability and insulinotropic action. In this study, the N‐terminally modified GLP‐1 analogue, N‐acetyl‐GLP‐1, was shown to be completely resistant to DPP IV, unlike native GLP‐1, which was rapidly degraded. Furthermore, culture of pancreatic ductal ARIP cells for 72 h with N‐acetyl‐GLP‐1 indicated a greater ability to induce pancreatic β‐cell‐associated gene expression, including insulin and glucokinase. Further investigation of the effects of stable GLP‐1 analogues on β‐cell differentiation is required to assess their potential in diabetic therapy.
Neuronal primary cilia: a review
Authors: Fuchs Jannon L. , Schwark Harris D. 
Published: January 2004

AbstractPrimary cilia in neurons have often been regarded as rare, vestigial curiosities. However, neuronal cilia are now gaining recognition as ubiquitous organelles in the mammalian brain, raising speculation about what their functions may be. They might have some features tailored for the nervous system and others that serve needs shared by a spectrum of other cell types. Here we review clues from the literature and present new data supporting several possibilities for the significance of neuronal cilia. Our immunocytochemical results show regional heterogeneity in neuronal cilia. Brain regions nearer to the cerebral ventricles had longer cilia, suggesting that they might sense chemicals such as peptides, originating from cerebrospinal fluid. In mutant Tg737orpkmice, most brain regions appeared to be missing cilia. The importance of intraflagellar transport proteins establishes a functional link between neuronal cilia and other primary cilia.
Endothelial dysfunction in congestive heart failure: ACE inhibition vs. angiotensin II antagonism
Authors: Schäfer Andreas , Fraccarollo Daniela , Tas Piet , Schmidt Isabel , Ertl Georg , Bauersachs Johann 
Published: January 2004

AbstractBackground:Endothelial dysfunction of the vasculature contributes to the elevated peripheral resistance and reduced myocardial perfusion in congestive heart failure (CHF). The present study systematically investigated the effect of angiotensin II (AT1)‐ receptor blockade on vascular superoxide (O2−) production and endothelial dysfunction.Methods and results:Vasodilator responses and O2− production were determined in aortic rings from Wistar rats with experimental CHF 10 weeks after extensive myocardial infarction and compared with sham‐operated animals (Sham). Rats were either treated with placebo (P), with the AT1‐receptor antagonist Irbesartan (50 mg kg−1 day−1) or with the ACE inhibitor Trandolapril (0.3 mg kg−1 day−1). In CHF‐P, endothelium‐dependent, acetylcholine‐induced relaxation was significantly attenuated compared with Sham‐P. Chronic treatment with Trandolapril or Irbesartan significantly improved endothelium‐dependent relaxation. Aortic O2− formation was markedly increased in CHF, and was not significantly affected by Trandolapril treatment, while it was reduced by Irbesartan. eNOS expression was reduced in CHF and normalised by both treatments.Conclusion:Endothelial vasomotor function in CHF rats was normalised by long‐term treatment with an ACE inhibitor or an AT1‐antagonist. Reduced aortic eNOS expression was normalised by both treatments, whereas aortic superoxide formation was only reduced by the AT1‐antagonist Irbesartan.
Urotensin II in patients with chronic heart failure
Authors: Krüger Stefan , Graf Jürgen , Kunz Dagmar , Stickel Tina , Merx Marc W. , Hanrath Peter , Janssens Uwe 
Published: January 2004

Background:Human Urotensin II (hU‐II) is the most potent vasoconstrictor known to date. HU‐II receptors are predominant in the human heart and arterial vessels, suggesting hU‐II to be of importance as a cardiovascular mediator.Methods:We studied 32 consecutive patients (60±12 years) with chronic heart failure (CHF) and 10 control subjects (54±12 years, n.s.) with cardiopulmonary exercise testing. Blood samples for the measurement of plasma hU‐II and big‐endothelin‐1 (big‐ET1) were obtained at rest and at peak exercise.Results:Peak VO2 was significantly higher in controls than in CHF patients (19.8±3.8 vs. 14.7±3.6 ml min−1 kg−1, P<0.001). Big‐ET1 levels were increased in CHF compared to controls at rest (2.8±1.8 vs. 1.7±0.1 fmol/ml, P<0.01) and at peak exercise (2.7±1.7 vs. 1.6±0.2 fmol/ml, P<0.005). HU‐II concentrations were comparable in patients with CHF and controls at rest (2990±1104 vs. 3290±508 pg/ml, n.s.) and peak exercise (3063±1185 vs. 3213±1188 pg/ml, n.s.). Resting hU‐II levels demonstrated no correlation with peak VO2 in controls or CHF patients.Conclusions:The measurement of circulating plasma levels of hU‐II does not seem to be very helpful in studying the effects of hU‐II in human cardiovascular regulation. A local paracrine or autocrine mediator effect of hU‐II in CHF is possible.
Diagnosis of periodontal manifestations of systemic diseases
Authors: Jordan Richard C. K. 
Published: January 2004

SummaryMany systemic diseases can mimic periodontitis or gingivitis. These include many immunologic, infectious, neoplastic and metabolic disorders. In comparison with periodontitis and gingivitis, these disorders are considerably less common. However, since their diagnosis and management differ, a high index of suspicion is frequently needed when confronted a patient presenting with gingival or periodontal disease. This chapter has reviewed a number of systemic conditions that may mimic clinically both gingivitis and chronic periodontitis and has focused on the features that may assist the clinician in making the diagnosis and providing specific therapies.
Electrophysiology of inducible atrial flutter in patients with atrioventricular nodal reentrant tachycardia
Authors: Liu Shaowen , Yuan Shiwen , Hertervig Eva , Kongstad Ole , Ljungstrom Erik , Bertil Olsson S. 
Published: January 2004

SummaryAn association between atrial flutter and atrioventricular nodal reentrant tachycardia (AVNRT) has been observed, but the underlying mechanisms are poorly defined. This issue was therefore investigated by comparing the electrophysiological properties of AVNRT patients with and without inducible atrial flutter and those of patients with a history of flutter. Twenty‐nine patients with clinically documented atrial flutter and 104 with AVNRT were studied. Atrial flutter was induced in 38 (37%) AVNRT patients during standardized electrophysiological testing before radiofrequency ablation. The atrial relative refractory periods in AVNRT patients with inducible flutter (260 ± 30 ms) were significantly shorter than those of either patients with a history of flutter (282 ± 30 ms; P = 0·02) or AVNRT patients without inducible flutter (284 ± 38 ms; P = 0·006). The atrial effective refractory periods in AVNRT patients with inducible flutter (205 ± 31 ms) were shorter than in AVNRT patients without inducible flutter (227 ± 40 ms; P = 0·01). The maximum AH interval during premature atrial stimulation in patients with clinical flutter (239 ± 94 ms) was shorter than in AVNRT patients either with (290 ± 91 ms; P = 0·04) or without inducible flutter (313 ± 101 ms; P = 0·002). However, no significant differences were found in the maximum AH interval achieved during incremental atrial pacing among different groups. Our data show that a non‐clinical flutter could more often be induced in those who had short atrial refractoriness. Despite their anatomical proximity, the slow pathway conduction of AVNRT and the isthmus slow conduction of flutter may be related to different mechanisms.
Electromyographic signs of neuromuscular fatigue are concomitant with further increase in ventilation during static handgrip
Authors: Hug F. , Faucher M. , Marqueste T. , Guillot Ch. , Kipson N. , Jammes Y. 
Published: January 2004

SummaryWe questioned if a non‐linear increase in ventilation defining a ventilatory threshold (VTh) accompanied the electromyographic (EMG) signs of neuromuscular fatigue. Indeed, the intramuscular accumulation of metabolites may activate the afferent nervous pathways responsible for both the ‘muscle wisdom’ phenomenon and the respiratory centre activation. During inframaximal (50%) handgrip sustained until exhaustion, minute ventilation (VE), VE/Vo2 and VE/Vco2 ratios were measured simultaneously with surface EMG of the ‘flexor digitorum’ muscle. VTh was defined as a non‐linear VE increase and/or an abrupt VE/Vo2 increase without any concomitant increase in the VE/Vco2 ratio. Handgrip was repeated during complete arterial blood flow interruption in order to suppress any venous return from the exercising forearm. In both control and blood flow interruption conditions, an abrupt increase in the VE/Vo2 ratio was measured in the majority of trials (13 of 15 and 14 of 15, respectively) and the EMG signs of neuromuscular fatigue (a decline in median frequency and/or a non‐linear increase in low‐frequency EMG energies, EL) were concomitant with the VTh determination. Thus, VTh occurs during sustained static contraction and is concomitant with EMG signs of neuromuscular fatigue. Neurogenic factors seem to be responsible for the two responses which persist despite the absence of any release of metabolites in the circulation.
Assessment of 99mTc‐sestamibi myocardial redistribution following acute myocardial infarction and revascularization
Authors: Kaltoft Anne , Bøttcher Morten , Rehling Michael 
Published: January 2004

SummaryRevascularization with primary percutaneous coronary intervention for ST segment elevation myocardial infarction results in restored epicardial flow in the majority of patients. However, in more than 25% of patients, flow does not translate into tissue perfusion. To assess revascularization success, it is necessary to evaluate beyond epicardial flow and to address tissue perfusion. 99mTc‐sestamibi single photon emission computed tomography (SPECT) might be useful in this setting, but whether sestamibi redistributes when administered during reperfusion has been debated. The aim of this study was to investigate whether clinically significant redistribution could be detected in a porcine model mimicking acute myocardial infarction and revascularization. Ten pigs were studied in a closed‐chest model of myocardial infarction. 99mTc‐sestamibi was administered during reperfusion, and SPECT was performed every 30 min for 4 h. The quantitative program CEQUAL was used for analysis and perfusion defects were reported in percentage. All animals had eight acquisitions. The size of the perfusion defect in the individual animals ranged from (mean ± SD) 13 ± 3 to 34 ± 2%. The difference between the first and the last perfusion defect in a single animal was (mean ± SD) 2·5 ± 5·3%, which is not statistically significant (P = 0·17). The slopes of regression lines obtained from plots of the individual values ranged from −1·39 to 0·76 with a mean of −0·23 ± 0·68, which is not statistically significant (P = 0·31). In conclusion, we found no sign of sestamibi redistribution in this experimental set‐up of reperfused myocardial infarction. If these findings can be extrapolated to clinical practice, then it means that acquisition can be performed at any time within the first 4 h after tracer injection without significant difference in perfusion assessment.
Peripheral pulse pressure responses to postural stress do not reflect those at the carotid artery
Authors: Steinback Craig D. , O'Leary Deborah D. , Wang Simon S. , Kevin Shoemaker J. 
Published: January 2004

SummaryObjective:  Interpretation of baroreflex cardiovascular control requires accurate assessment of pulse pressure (PP) in central arteries under conditions of varying systemic or hydrostatic pressure. The objective of this study was to examine whether changes in PP during postural stress were similar in the peripheral versus carotid arteries.Design:  Protocol A: Pulse pressure was measured in both the left (Millar tonometer) and right (Colin Pilot) radial arteries, and in the finger (Finapres) in seated subjects (n = 7) who performed Valsalva's manoeuvre. Protocol B: PP was measured from the carotid (Millar tonometer), and from the finger and wrist kept at the level of the carotid artery, during supine and 60° head‐up postures.Results:  Protocol A: Pulse pressures during Valsalva's manoeuvre were highly correlated between all devices (r = 0·6–0·8). Protocol B: compared with supine, PP was reduced in both the finger and wrist during head‐up‐tilt (HUT) (P<0·05), but not in the carotid artery.Conclusions:  During Valsalva manoeuvers the Millar and Colin tonometers similarly tracked PP over a wide range of rapidly changing pressures. This observation provided confidence for the further use of the hand‐held device for central measurements during changes in posture. The results from Protocol B indicate that peripheral PP measurements are not suitable surrogates for carotid pulse pressures during HUT.
Estimate of pulmonary diffusing capacity for oxygen during exercise in humans from routine O2 and CO2 measurements
Authors: Vidal Melo M. F. , Barazanji K. , Winga E. , Johnson R. L. 
Published: January 2004

SummaryA method to estimate pulmonary diffusing capacity for O2 (DLo2) during exercise based on routine O2 and CO2 transport variables is presented. It is based on the fitting of a mathematical model to gas exchange data. The model includes heterogeneity (described as two exchanging compartments), diffusion limitation and right‐to‐left shunt. Mass conservation equations and Bohr integration were solved to calculate partial pressures in each compartment. Diffusion was distributed with perfusion. Two‐compartment ventilation and perfusion distributions were estimated at rest during conditions of negligible diffusion limitation. These distributions were used during hypoxic and normoxic exercise to obtain the DLo2 from the model computations (DLo22C) compatible with experimental data. Three normals, four sarcoid patients and four patients after lung resection were studied. An independent technique for carbon monoxide was used to provide experimental estimates of DLo2 (DLo2EXP, rebreathing technique for sarcoid patients and single breath for lung resection). DLo22C was highly correlated with DLo2EXP (r2 = 0·95, P<0·001) and the slope of the regression line was not statistically different from 1. The mean (DLo2EXP − DLo22C) difference was −1·0 ± 7·4 ml min−1 mmHg−1. The results suggest that use of a refined analytical procedure allows for assessment of DLo2 from routine O2 and CO2 measurements comparable with those obtained from independent carbon monoxide techniques. The method may be an alternative for estimates of DLo2 during exercise.
Regional ventilation and distribution of emphysema – a quantitative comparison
Authors: Johansson Åke , Vikgren Jenny , Moonen Michaela , Tylén Ulf , Bake Björn 
Published: January 2004

SummaryThe distribution of ventilation and emphysema throughout the lung was compared in 20 emphysematous patients who were candidates for lung volume reduction surgery. Ventilation distribution among 1·6‐cm‐high stripe regions was obtained in supine position by planar gamma camera scintigraphy after inhalation of technegas®. Results from nine healthy subjects provided normal stripe count rates. Patient count rates were expressed as the difference from predicted normal stripe count rate (ΔSVI). Thus, ΔSVI is a relative index of abnormal ventilation. Emphysema was assessed quantitatively by a density mask method on corresponding slices of high resolution computed tomography (HRCT). The results show that in the majority of patients, there is a highly significant relationship between the degree of stripe hypoventilation and the amount of distribution of emphysema, but in some patients no such relationship is found. We speculate that the distribution of airway obstruction not necessarily follows the distribution of emphysema, which could explain the lack of concordance between ventilation and emphysema distribution in some patients. We conclude that ventilation scintigraphy contains complementary information to lung HRCT.
Efficacy of mosquito nets treated with insecticide mixtures or mosaics against insecticide resistant Anopheles gambiae and Culex quinquefasciatus (Diptera: Culicidae) in Côte d'Ivoire
Authors: Hougard J.-M. , Corbel V. , N'Guessan R. , Darriet F. , Chandre F. , Akogbéto M. , Baldet T. , Guillet P. , Carnevale P. , Traoré-Lamizana M. 
Published: January 2004

AbstractOnly pyrethroid insecticides have so far been recommended for the treatment of mosquito nets for malaria control. Increasing resistance of malaria vectors to pyrethroids threatens to reduce the potency of this important method of vector control. Among the strategies proposed for resistance management is to use a pyrethroid and a non-pyrethroid insecticide in combination on the same mosquito net, either separately or as a mixture. Mixtures are particularly promising if there is potentiation between the two insecticides as this would make it possible to lower the dosage of each, as has been demonstrated under laboratory conditions for a mixture of bifenthrin (pyrethroid) and carbosulfan (carbamate). The effect of these types of treatment were compared in experimental huts on wild populations of Anopheles gambiae Giles and the nuisance mosquito Culex quinquefasciatus Say, both of which are multi-resistant. Four treatments were evaluated in experimental huts over six months: the recommended dosage of 50 mg m−2 bifenthrin, 300 mg m−2 carbosulfan, a mosaic of 300 mg m−2 carbosulfan on the ceiling and 50 mg m−2 bifenthrin on the sides, and a mixture of 6.25 mg m−2 carbosulfan and 25 mg m−2 bifenthrin. The mixture and mosaic treatments did not differ significantly in effectiveness from carbosulfan and bifenthrin alone against anophelines in terms of deterrency, induced exophily, blood feeding inhibition and overall mortality, but were more effective than in earlier tests with deltamethrin. These results are considered encouraging, as the combination of different classes of insecticides might be a potential tool for resistance management. The mixture might have an advantage in terms of lower cost and toxicity.