Самоподобие массивов сетевых публикаций по компьютерной вирусологии

Описан подход к организации анализа потока тематических публикаций по компьютерной вирусологии, представленных в web-пространстве. Обоснована фрактальная природа информационных потоков, описаны основные алгоритмы, применяемые в процессе исследований, а также приведены прогнозные выводы на основе свойств персистентности временных рядов.Описано підхід до організації аналізу потоку тематичних публікацій з комп’ютерної вірусології, які наведені у web-просторі. Обґрунтовано фрактальну природу інформаційних потоків, описано основні алгоритми, що застосовуються в процесі досліджень, а також наведено прогнозні висновки на базі властивостей персистентності часових рядів.An approach to the organization of the analysis of a thematic publications stream on computer virology, submitted in web-space, is described. The fractal nature of information streams is proved, the basic algorithms used during researches are described and forecasts conclusions on the basis of persistent properties of time series are given

Identification of Additional Trials in Prospective Trial Registers for Cochrane Systematic Reviews

Background: Publication and selective outcome reporting bias are a threat to the validity of systematic reviews. Extensive searching for additional trials in prospective trial registers could reduce this problem. We have evaluated how authors of Cochrane systematic reviews currently make use of trial registers as an additional source for the identification of potentially eligible trials. Methodology/Principal Findings: We included 210 systematic Cochrane reviews of interventions published between 2008 and 2010 of which the protocol was first published in 2008. When prospective trial registers were searched we recorded the names of the register(s), the authors' motive(s) and if they yielded any extra trials. In 80 reviews (38.1%) the authors had searched in one or more prospective trial register(s) of which 55% had searched in overlapping search portals and individual registers. Most frequently assessed were the MetaRegister (66.3%) and Clinicaltrials.gov (60%) which is in sharp contrast of other registers or portals like the WHO ICTRP Search Portal (20%). Reported motives to use registers were to identify ongoing trials (83.3%), to identify unpublished outcomes or trials (23.5%), to identify recently published trials (11.8%), or to identify any relevant trial (3.9%). In 28 reviews (35%) the authors had selected (ongoing) trials identified in trial registers as potentially eligible. Discussion: Trial registers as an additional source of information are gaining acknowledgement amongst Cochrane reviewers. Nevertheless, searches seem to be inefficient as overlapping databases are frequently consulted, while the WHO ICTRP Search Portal that includes the data from all approved registers worldwide is being underused. Moreover, the emphasis is now on the identification of ongoing trials, although the prospective registers offer a broader potential. Further familiarity of registers and guidance how to search and to report will help to implement this as a common method and utilize the full potential of prospective trial registers for systematic review

Overview of combinations of trial registers/search portals that were searched in 80 Cochrane reviews.

<p>Overview of combinations of trial registers/search portals that were searched in 80 Cochrane reviews.</p

Overview of trial registers that were searched in 80 Cochrane reviews.

*<p>Most review authors searched in more than one register. Therefore, the summation of percentages exceeds 100%.</p

Methods applied for identification of trials in addition to searching in biomedical databases in 210 Cochrane reviews.

*<p>Most review authors applied multiple strategies to identify additional trials. Therefore, the summation of percentages exceeds 100%.</p

Clinical diagnostic evaluation for scaphoid fractures: a systematic review and meta-analysis

To provide an overview of available clinical evaluation tests for scaphoid fractures and to compare their diagnostic accuracies. PWe performed a systematic review of all studies assessing diagnostic characteristics of clinical evaluation in scaphoid fractures by searching MEDLINE, EMBASE, Cochrane, and CINAHL databases. Only studies on clinical testing prior to radiographic evaluation and with acceptable reference standard for occult fractures were included. Thirteen relevant articles were analyzed that described a total of 25 tests. Diagnostic characteristics of the tests were used to construct contingency tables. If possible, data were pooled and summary receiver operating characteristic curves were fitted. Anatomic snuff-box tenderness (ASB, 8 studies, 1,164 patients) and longitudinal thumb compression (LTC, 8 studies, 961 patients) had sufficient data for statistical analyses. Sensitivity for ASB ranged from 0.87 to 1.00; for LTC, 0.48 to 1.00. Specificity of ASB ranged from 0.03 to 0.98; for LTC, 0.22 to 0.97. Owing to considerable heterogeneity, pooled estimate points were not calculated. Other high-sensitivity tests were scaphoid tubercle tenderness, with sensitivity and specificity ranging from 0.82 to 1.00 and 0.17 to 0.57, respectively, and painful ulnar deviation, ranging from 0.67 to 1.00 and 0.17 to 0.60, respectively. Three studies showed that combining tests increased the specificity and post-test fracture probability while maintaining high sensitivity. Quality assessment showed high or unclear risk of bias and applicability concerns in reference standard and patient selection. Twelve study designs were prospective, and 1 was retrospective. Anatomical snuff box tenderness was the most sensitive clinical test. The low specificity of the clinical tests may result in a considerable number of overtreated patients. Combining tests improved the post-test fracture probability. This can be used to limit unnecessary immobilization, number of hospital visits, and use of imaging. The data presented herein may help to develop clinical prediction rules that could increase specificity without reducing sensitivity. Diagnostic I

Meta-epidemiologic analysis indicates that MEDLINE searches are sufficient for diagnostic test accuracy systematic reviews

To investigate how the summary estimates in diagnostic test accuracy (DTA) systematic reviews are affected when searches are limited to MEDLINE. A systematic search was performed to identify DTA reviews that had conducted exhaustive searches and included a meta-analysis. Primary studies included in selected reviews were assessed to determine whether they were indexed on MEDLINE. The effect of omitting non-MEDLINE studies from meta-analyses was investigated by calculating the summary relative diagnostic odds ratio (RDORs) = DORMEDLINE only/DORall studies. We also calculated the summary difference in sensitivity and specificity between all studies and only MEDLINE-indexed studies. Ten reviews contributing 15 meta-analyses met inclusion criteria for quantitative analysis. The RDOR comparing MEDLINE-only studies with all studies was 1.04 (95% confidence interval [CI], 0.95, 1.15). Summary estimates of sensitivity and specificity remained almost unchanged (difference in sensitivity: -0.08%; 95% CI -1% to 1%; difference in specificity: -0.1%; 95% CI -0.8% to 1%). Restricting to studies indexed on MEDLINE did not influence the summary estimates of the meta-analyses in our sample. In certain circumstances, for instance, when resources are limited, it may be appropriate to restrict searches to MEDLINE. However, the impact on individual reviews cannot be predicte

Systematic overview finds variation in approaches to investigating and reporting on sources of heterogeneity in systematic reviews of diagnostic studies

To examine how authors explore and report on sources of heterogeneity in systematic reviews of diagnostic accuracy studies. A cohort of systematic reviews of diagnostic tests was systematically identified. Data were extracted on whether an exploration of the sources of heterogeneity was undertaken, how this was done, the number and type of potential sources explored, and how results and conclusions were reported. Of the 65 systematic reviews, 12 did not perform a meta-analysis and eight of these gave heterogeneity between studies as a reason. Of the 53 reviews containing a meta-analysis, 40 explored potential sources of heterogeneity in a formal manner and 27 identified at least one source of heterogeneity. The reviews not investigating heterogeneity were smaller than those that did (median [interquartile range {IQR}], 8 [5-15] vs. 14 [11-19] primary studies). Twelve reviews performed a sensitivity analysis, 25 stratified analyses, and 19 metaregression. Many sources of heterogeneity were explored compared with the number of primary studies in a meta-analysis (median ratio, 1:5). Review authors placed importance on the exploration of sources of heterogeneity; 37 mentioned the exploration or the findings thereof in the abstract or conclusion of the main text.results Methods for investigating sources of heterogeneity varied widely between reviews. Based on our findings of the review, we made suggestions on what to consider and report on when exploring sources of heterogeneity in systematic reviews of diagnostic studie