1,720,980 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
Changes in gastric electrical activity following upper gastrointestinal surgery: The electrophysiological and histological changes that occur following upper gastrointestinal surgery
No full textIntroduction
Upper gastrointestinal surgery and hepaticopancreatobiliary surgery comprise a major subset of general surgery. While most patients recover well post-operatively, some patients unfortunately experience persistent post-surgical symptoms including nausea, vomiting, delayed gastric emptying, and reflux. Recent research has focused on the role of aberrant gastrointestinal electrophysiology in contributing to post-surgical gastric function, enabled by advances in high-resolution (HR) gastric mapping technologies. This thesis therefore aimed to better understand changes in gastrointestinal electrophysiology, relevant histology, along with relationships to symptoms and quality of life following upper gastrointestinal surgery.
Methods
HR gastric serosal (invasive) mapping was performed on porcine models, including healthy weaner pigs and those who underwent a formation of gastrointestinal anastomosis two weeks prior. Data on gastric slow wave frequency, velocity, amplitude, and propagation direction were analysed. Histology was used to assess Interstitial Cells of Cajal (ICC). HR body surface gastric mapping was also performed to assess the changes in gastric electrophysiology and motility following surgeries of different cohorts including oesophagectomies, sleeve gastrectomy, gastric bypass, and pancreaticoduodenectomies in human subjects. Data on gastric slow wave frequency, amplitude and meal response, were obtained and analysed.
Results
Normal physiological relationships between gastric slow wave parameters were defined, together with changes related to ICC loss and senescence. In the porcine model, changes in gastric frequency, velocity and amplitude were identified at 2 weeks following the formation of gastrointestinal anastomosis, with intestinal slow waves showing capability to cross through the anastomotic scar and into the stomach. There was also consistent regrowth of ICC into the anastomosis. The translational significance of these findings was demonstrated in a patient with chronic gastric dysmotility, with these abnormalities termed “Gastric Aberrant Pathway (GAP) Syndrome". In humans, abnormal gastric slow wave frequency, rhythm and other parameters were variably identified, dependent on cohort of post-surgical patients, and these changes show correlations with patient symptoms and quality of life in post-bariatric cohorts.
Conclusion
The results of this thesis advance the understanding of normal gastric electrophysiology, and demonstrate several novel abnormalities in gastrointestinal electrophysiology following upper gastrointestinal surgery. These insights will inform future diagnostic, preventative and therapeutic strategies for post-surgical gastric dysfunction
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
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
Can Psychological Factors and Colonic Motility Predict Postoperative Complications? An Observational Pilot Study
No full textFull Text is available to authenticated members of The University of Auckland only.Prolonged postoperative ileus (PPOI) describes delayed bowel function recovery and oral intake intolerance following surgery. PPOI affects up to 30% of colorectal patients, causes discomfort, complication risk, lengthen hospital stays and increases costs. Recent evidence suggests heightened preoperative anxiety may contribute to PPOI by dysregulating gastrointestinal motility patterns.
This study aimed to evaluate the feasibility of a large observational study investigating the role of psychological factors on gut function and recovery following major surgery.
An observational pilot study was conducted at Auckland City and North Shore Hospitals. Nine colonic and nine non-colonic surgical patients (undergoing major non-spinal orthopaedic, breast or non-bowel-abdominal) were recruited. Surgical anxiety, optimism, depression, stress, and expectations were assessed at baseline. Baseline, preoperative and postoperative colonic electrophysiology and electrodermal activity were measured using Body Surface Mapping Electrocolonography (BSM EColG) and Empatica E4 wristband. Primary outcomes were protocol and device feasibility. Secondary outcomes included preliminary effect sizes between psychological predictors and postoperative bowel function recovery. A factor analysis was completed to create two overall psychological constructs named ‘general negative affect’ and ‘surgical mindset’.
Eligibility rates, recruitment rates and sample retention were acceptable in both patient groups. Self-reported measures were appropriate and performed well except the repeated state anxiety measure. Both devices were acceptable, appropriate, uncomplicated to place and worn for the full study duration in most patients. Empatica E4 data quality was moderate due to some missing HRV data and low levels of EDA artefact. EColG demonstrated acceptable connectivity. PPOI was only diagnosed in 33% of the colonic sample. Preliminary analyses were non-significant but suggest increased PPOI risk with negative surgical mindset. General negative affect and negative surgical mindset had mixed non-significant effects on time until overall and individual bowel function recovery was achieved. Exploratory analyses indicate a difference in sympathetic output (p = .002) but not state anxiety between baseline and preoperative timepoints.
Eligibility and recruitment processes were feasible and appropriate for this patient population. Patients were accepting of and agreeable to wear the both the BSM EColG and Empatica E4
devices. These devices demonstrated adequate data quality. Current methods and devices are suitable for a large observational study. Preliminary results suggest psychological factors may have deleterious effects on postoperative bowel function recovery
Redefining Low Anterior Resection Syndrome
No full textLow Anterior Resection Syndrome (LARS) is used to describe bowel dysfunction
which patients experience after rectal cancer treatment. There is interest in the field as
the accumulating evidence reinforces that LARS is common. However, lack of definition
and complex pathophysiological mechanism have limited the ability to progress
the understanding of LARS.
The overall aims of this thesis are to critically advance the clinical understanding of
low anterior resection syndrome (LARS) and propose a consensus definition of LARS.
To achieve these aims, it was necessary to explore the current clinical definition, measurement,
prevalence, and factors associated with LARS.
Clinical and translational research methods were used including review and synthesis
of the literature, a case-control study, secondary analyses of randomized control
trials, a clinical trial, a Delphi survey and consensus meetings.
Cross-sectional measurement of LARS in multiple populations (New Zealand, Australia,
Sweden, Denmark) found that the majority of patients suffer from LARS after
rectal resection. Cross-sectional assessment in a control group also provided the novel
finding that there is a significant rate of similar symptoms in an age- and sex-matched
non-operative population (major LARS 26%).
Assessment of risk factors in non-controlled populations demonstrated the difficulty
differentiating the effect of inter-related factors. Lower anastomotic height and radiotherapy
were consistently associated with LARS and there was a suggestion that the
use of an ileostomy may also be associated with LARS. Surgical approach showed no
association with LARS.
Differences in colonic motility after rectosigmoid resection, specifically in the cyclic
motor pattern, were found using high resolution manometry. These were more pronounced
in patients suffering from LARS supporting the concept of a rectosigmoid
brake and offering insights into potential biomarkers and therapeutic options for LARS.
An international consensus definition of LARS that incorporates both symptoms
and consequences was constructed by reviewing the literature and consulting major
stakeholders, including patients.
This work provides a series of original contributions to the literature. The international
consensus definition will allow future advances to standardise the measurement
of LARS. The findings relating to use of an ileostomy and colonic motility may enable
future advances in prevention, diagnosis, or treatment of LARS
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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