1,720,962 research outputs found
Influence of ventilation mode on neonatal cerebral blood flow and volume
No full textBACKGROUND:
Cerebral hemodynamics is supposed to be influenced by the different ventilation approach. Ventilation support can be classified as non-invasive (N-CPAP) or invasive (SIMV and HFV), the last known to induce endotrauma. Our aim was the non-invasive NIRS assessment of neonatal absolute cerebral blood flow (CBF) and relative cerebral blood volume changes (DeltaCBV) during synchronized intermittent ventilation (SIMV), or high frequency ventilation (HFV) and nasal continuous positive airways pressure (CPAP).
METHODS:
An observational study in a tertiary referral NICU. CBF and DeltaCBV changes were assessed in 41 preterm newborn infants with respiratory distress syndrome treated using mechanical ventilation or the CPAP device.
RESULTS:
Basal chromophore traces enabled DeltaCBV (mL/100 g) changes to be calculated. CBF was calculated in mL/100 g/min from the saturation rise integral and rate of rise [O(2)Hb-HHb]. Median DeltaCBV was 0.07 (range 0.01-0.13) in SIMV group, 0.07 (0.01-0.19) in HFV group and 0.13 (0.10-1.28) in CPAP group. Median CBF was 14.44 (2.70-32.10), 9.20 (2.94-19.58) and 31.69 (13.59-34.93) respectively. A multiple regression model showed a significant correlation between DeltaCBV or CBF and ventilation approach.
CONCLUSION:
In the light of our results, we might speculate that, assuming that hemodynamic autoregulation is safe and arterial blood pressure is preserved, ventilation per se influences brain circulation
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
Near-infrared spectroscopy measure of limb peripheral perfusion in neonatal arterial thromboembolic disease.
No full textAIM:
In critically ill neonates, peripheral perfusion and oxygenation assessment may provide indirect information on circulatory failure in limb arterial thromboembolic emergencies. Aims of our study were: 1) to evaluate the changes on tissue oxygenation index, oxyhemoglobin, deoxyhemoglobin and blood volume obtained by near-infrared spectroscopy (NIRS) on the infants legs; 2) to compare them with ultrasonographic data.
METHODS:
Tissue oxygenation index (TOI), oxyhemoglobin (O2Hb), deoxyhemoglobin (HHb) and blood volume (BV) differences were assessed by NIRS on the calf of 8 newborn infants (median weight 1995, range 585-3010 g; median gestational age 32.5, range 26-40 wks). An ultrasonographic scan of the arterial system was performed before the NIRS measurements, to validate the site of arterial occlusion.
RESULTS:
A t-test for independent samples showed lower values in the affected limb for all NIRS measurements. TOI measurements displayed lower values in the thromboembolic limb (mean 44.79±12%) versus unaffected (mean 47.95±17.08%) (P=0.0001). Mean (SD) peak systolic velocity in the patent artery below the occlusion decreased from 108±25 cm/s in the normal limb to 25.6±28 cm/s in the thrombus site (P=0.02).
CONCLUSION:
In neonatal intensive care units, measurement of limb peripheral perfusion and oxygenation seems to be clinically useful in arterial thromboembolic emergencie
Pneumomediastinum and pneumopericardium in an 11-year-old rugby player: a case report.
Full text linkObjective: Pneumomediastinum and pneumopericardium are rare occurrences in young athletes, but they can result in potentially life-threatening consequences. Background: While involved in a rugby match, an 11-year-old boy received a chest compression by 3 players during a tackle. He continued to play, but 2 hours later, he developed sharp retrosternal chest pain. A chest radiograph and an echocardiograph at the nearest emergency department showed pneumopericardium and pneumomediastinum. Differential Diagnosis: Sternal and rib contusions, rib fractures, heartburn, acute asthma exacerbation, pneumomediastinum, pneumopericardium, pneumothorax, traumatic tracheal rupture, myocardial infarction, and costochondritis (Tietze syndrome). Treatment: Acetaminophen for pain control. Uniqueness: To our knowledge, this is the only case in the international literature of the simultaneous occurrence of pneumomediastinum and pneumopericardium in a child as a consequence of blunt chest trauma during a rugby match. Conclusions: Pneumomediastinum and pneumopericardium may be consequences of rugby blunt chest trauma. Symptoms can appear 1 to 2 hours later, and the conditions may result in serious complications. Immediate admission to the emergency department is required
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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