1,720,964 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Prevalence and correlates of advanced retinopathy in a large selected hypertensive population. The Evaluation of Target Organ Damage in Hypertension (ETODH) study
No full textObjective. To describe the prevalence of advanced retinal microvascular lesions and their associations with cardiac and extracardiac signs of target organ damage (TOD) in a large selected hypertensive population. Methods. A total of 2172 nondiabetic untreated and treated uncomplicated essential hypertensives consecutively attending for the first time our hospital outpatient hypertension clinic and included in the Evaluation of Target Organ Damage in Hypertension (ETODH), an observational ongoing registry of hypertension-related TOD, were considered for this analysis. Advanced hypertensive retinopathy was defined by the presence of any of the following lesions: flame-shaped haemorrhages, soft exudates or cotton wool spots and papilloedema. Left ventricular hypertrophy (LVH), carotid structural abnormalities, such as plaques and intima media (IM) thickening, and microalbuminuria were diagnosed according to the 2003 ESH/ESC guidelines criteria. Results. Among the whole study population, 33 patients (1.5%) were found to have advanced hypertensive retinopathy. Patients with these retinal lesions were similar to those without for age, body mass index, known duration of hypertension, smoking habit, total serum cholesterol, fasting blood glucose and prevalence of antihypertensive treatment, whereas mean systolic and diastolic blood pressures were higher in the former group. The prevalence rates of LVH, carotid plaques, carotid IM thickening and microalbuminuria in patients with and without retinopathy were 57%, 67%, 69%, 19% and 25%, 47%, 44%, 12%, respectively. In a multivariate logistic regression analysis, advanced retinopathy was significantly associated with LVH (OR=4.0), carotid IM thickening (OR=2.9), carotid plaques (OR=2.8), but not with micro albuminuria. Conclusions. Our study indicates that: (i) advanced retinopathy is a rare finding in non-diabetic hypertensive patients seen in a specialist setting, (ii) a strong relation exists between retinal microvascular lesions and cardiac and macrovascular markers of TOD
Aortic coarctation suspected by echo-doppler of renal arteries in hypertensive patients referred to a hospital out-patient hypertension clinic
No full textAmbulatory blood pressure, target organ damage and left atrial size in never-treated essential hypertensive individuals
No full textObjective: To investigate the relationship between ambulatory blood pressure and different markers of target organ damage with left atrial size in never-treated essential hypertensive individuals. Methods: A total of 519 grade 1 and 2 hypertensive patients (mean age 46 ± 12 years), referred for the first time to our outpatient clinic, underwent routine examinations: 24-h urine collection for microalbuminuria, ambulatory blood pressure monitoring over two 24-h periods in 4 weeks, echocardiography and carotid ultrasonography. Results Left atrial diameter was increased in 17.3% of patients. No significant differences were found between subjects with and without increased left atrial size with regard to sex, duration of hypertension, clinic and mean 48-h ambulatory blood pressure, and daytime and night-time values. Compared with 429 patients with normal left atrial size, the 90 patients with enlarged left atria were older, had higher body mass index, were more frequently smokers, and included more individuals with the metabolic syndrome. The prevalence of left ventricular hypertrophy, of intima-media thickening, but not of microalbuminuria was significantly higher in subjects with increased left atrial size. Conclusion Left atrial enlargement is not an early echocardiographic finding in relatively young never-treated hypertensive individuals, as its prevalence is lower than that of well-validated markers of target organ damage, and it is unrelated to ambulatory blood pressure. Overweight, left ventricular hypertrophy, carotid 4ntima-media thickening and metabolic syndrome are independent predictors of left atrial dimension, suggesting that changes in left atrial size represent an adaptive response when high blood pressure is associated with other cardiovascular or metabolic abnormalities
Isolated ambulatory hypertension and changes in target organ damage in treated hypertensive patients
No full textIsolated ambulatory hypertension is a condition characterized by elevated ambulatory but normal clinic blood pressure ( BP), and has been reported to be associated with increased cardiovascular risk in untreated subjects. However, little is known about the relationship between this condition and intermediate end points such as target organ damage ( TOD) in treated hypertensives. We investigated the impact of isolated ambulatory hypertension on left ventricular hypertrophy ( LVH) and microalbuminuria ( MA) in a selected sample of treated nondiabetic hypertensives with effective and prolonged clinic BP control ( BP < 140/ 90 mmHg). Clinic BP measurements, routine diagnostic procedures, echocardiography and 24- h urine collection for MA, were undertaken in 80 patients ( mean age 53 +/- 8 years) with essential hypertension attending our hospital outpatient centre at baseline and after an average follow- up of 30 months. At follow- up evaluation BP status was assessed by self- measurement of BP and ambulatory BP monitoring ( ABPM). At the follow- up visit, 51 out of 80 patients ( 63.7%) reached a BP control according to ABP ( average daytime BP < 132/ 85 mmHg) criteria ( group I) whereas the remaining 29 did not ( group II); home BP was controlled ( BP < 135/ 85 mmHg) in all members of group I and in 86% of group II. In the overall study population, mean Sokolow voltage, LV mass index ( LVMI) and urinary albumin excretion ( UAE) decreased compared to baseline from 24.1 +/- 5.0 to 18.9 +/- 5.1 mm ( P < 0.05), 115.6 +/- 24.1 to 97.7 +/- 21.6 g/ m(2) ( P < 0.01), 11.8 +/- 23.7 to 5.8 +/- 14.9 mg/ 24 h ( P < 0.05), respectively. The prevalence of ECG LVH, altered LV patterns and MA fell from 7.5 to 2.5% ( P = NS), from 45 to 25 ( P < 0.01) and from 13.7 to 5.1% ( P < 0.05), respectively. However, when data were analysed separately for the two groups a significant decrease of echo LVH and MA was found only in patients with controlled ABP. LVMI and MA decreased from 117.1 +/- 23.1 to 95.9 +/- 22.1 g/ m(2) ( P < 0.01) and 12.8 +/- 24.7 to 4.1 +/- 5.7 mg/ 24 h ( P < 0.05) in group I, and from 114.1 +/- 24.8 to 102.3 +/- 20.3 ( P = NS) and 11.9 +/- 22.1 to 6.3 +/- 18.1 mg/ 24 h ( P = NS) in group II. In conclusion, in the present study isolated ambulatory hypertension in treated patients is associated with a lack of regression in cardiac and extracardiac TOD, suggesting that a tight BP control throughout the 24 h plays a key role in lowering hypertension- induced structural and functional alterations at cardiac and renal level
Prevalence and correlates of left atrial enlargement in essential hypertension : role of ventricular geometry and the metabolic syndrome
No full textBackground: The cardiac effects of hypertension include a variety of structural changes such as increases in left ventricular mass (LVM) and left atrium (LA) size. Although data on hypertension-induced left ventricular changes are extensive, relatively little information is available on LA size from large-scale studies. Objective: We sought to assess the prevalence of LA enlargement in a large selected hypertensive population and to determine the relations of LA size to several biologic variables including left ventricular hypertrophy (LVH) and metabolic disturbances. Methods: A total of 2500 untreated and treated uncomplicated essential hypertensives consecutively attending, for the first time, our hospital out-patient hypertension clinic and included in the Evaluation of Target Organ Damage in Hypertension, an observational ongoing registry of hypertension-related target organ damage (TOD), were considered for this analysis. All patients underwent extensive clinical, laboratory and ultrasonographic investigations searching for cardiac (and extracardiac) TOD. The LA was considered enlarged when its anteroposterior diameter exceeded 3.7 cm in women and 4.1 cm in men. LVH was defined according to two different criteria: ≥ 125 g/m2 in men and ≥ 110 g/m2 in women; or ≥ 51 g/m2.7 in men and ≥47 g/m2.7 in women. Results: Enlarged LA diameter was present in 24.5% of women and in 21.5% of men. Compared with 1925 patients with normal LA size, the 575 patients with enlarged LA were older, more frequently overweight, had higher systolic blood pressure and included a greater proportion of subjects under antihypertensive treatment, with diabetes and metabolic syndrome. Both LA size and prevalence of LA enlargement differed significantly in relation to left ventricular geometry and LVM, being greater in patients with concentric or eccentric LVH than in those with left ventricular concentric remodeling or normal geometry. The prevalence of LA enlargement was similar in patients with concentric and eccentric LVH. According to a logistic regression analysis, overweight, LVH, fasting blood glucose > 7.0 mmol/l and metabolic syndrome were the main independent predictors of LA enlargement in the overall population as well as in both untreated and treated hypertensive subgroups. Conclusions: Our study suggests that: LA enlargement is a common echocardiographic finding in selected essential hypertensive patients with different left ventricular geometric patterns; LA size and LA enlargement is related to LVM rather than the type of LVH; and, in addition to LVH, overweight, high fasting glucose and metabolic syndrome are associated with LA dimensions
Aortic coarctation suspected by Doppler echocardiography of renal arteries in hypertensive patients referred to a hospital outpatient hypertension clinic
No full textCoarctation of the aorta is the fourth most frequent form of congenital cardiovascular disease, which is diagnosed by the presence of higher blood pressures in the arms than in the legs. In this report we describe 3 cases of aortic coarctation, in which the correct diagnosis was suspected only months or years after the detection of hypertension, when a renal ultrasound examination was requested, despite the fact that the hallmarks of the disease were present at the physical examination in all patients. A marked reduction in renal flow velocities was suggestive of proximal aortic stenosis in all 3 cases. We conclude that the diagnosis of aortic coarctation, an uncommon but not so rare form of secondary hypertension, by renal ultrasonography rather than by a complete physical examination, reflects a commitment failure of physicians in everyday management of hypertension
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