Extensive retreat and re-advance of the West Antarctic Ice Sheet during the Holocene.

To predict the future contributions of the Antarctic ice sheets to sea-level rise, numerical models use reconstructions of past ice-sheet retreat after the Last Glacial Maximum to tune model parameters 1 . Reconstructions of the West Antarctic Ice Sheet have assumed that it retreated progressively throughout the Holocene epoch (the past 11,500 years or so)2-4. Here we show, however, that over this period the grounding line of the West Antarctic Ice Sheet (which marks the point at which it is no longer in contact with the ground and becomes a floating ice shelf) retreated several hundred kilometres inland of today's grounding line, before isostatic rebound caused it to re-advance to its present position. Our evidence includes, first, radiocarbon dating of sediment cores recovered from beneath the ice streams of the Ross Sea sector, indicating widespread Holocene marine exposure; and second, ice-penetrating radar observations of englacial structure in the Weddell Sea sector, indicating ice-shelf grounding. We explore the implications of these findings with an ice-sheet model. Modelled re-advance of the grounding line in the Holocene requires ice-shelf grounding caused by isostatic rebound. Our findings overturn the assumption of progressive retreat of the grounding line during the Holocene in West Antarctica, and corroborate previous suggestions of ice-sheet re-advance 5 . Rebound-driven stabilizing processes were apparently able to halt and reverse climate-initiated ice loss. Whether these processes can reverse present-day ice loss 6 on millennial timescales will depend on bedrock topography and mantle viscosity-parameters that are difficult to measure and to incorporate into ice-sheet models.

Linking forage choice behavior of goats with the metabolome of contrasting silages.

The interrelationships between silage preference of ruminants and compounds that may affect forage choice are not yet fully enlightened. Analysis of the forage metabolome in addition to conventional chemical analysis and preference trials can provide new insights. Six silage treatments each of alfalfa (AL) and red clover (RC), with different dry matter concentrations (222-391 g/kg), silage additives, and intended addition of soil, were produced in quadruplicate to obtain a range of qualities. After 120 d of ensiling, silages were sampled for chemical analysis, vacuum-packed, and refrigerated for subsequent preference trials with goats. Within 21 d, each possible combination of 2 silages and an AL hay that served as control (n = 21) was presented to goats (Saanen-type wethers, n = 8, body weight 105 ± 2.7 kg) for 3 h for ad libitum intake. Comparisons among means for 3-h dry matter intake (DMI) for forages offered in choice situations were made using variance analysis, including terms for treatment and animal and the Waller-Duncan k-ratio t-test to separate means. The most preferred and avoided treatments of AL and RC silage amounted to 863, 858, 226, and 282 g DMI/3 h, respectively. To further explore relations between silage composition and preference, a metabolome analysis of the most preferred and most avoided AL and RC treatments were conducted. Metabolites (all low molecular weight molecules) were analyzed by a nontargeted metabolite profiling in the range of 50-1,700 Da. Metabolites showing the most distinct difference between preferred and avoided silages were identified by partial least squares discriminant analysis. In the 2 selected treatments of each plant species (those that were most different in forage preference), more than 6,400 compounds were detected and 2,010 were identified. Between preferred and avoided treatments, 934 of the detected compounds differed in RC and 1,860 in AL, of which 475 were altered in both plant species (251 were reduced and 186 were increased; only 38 behaved contrarily, meaning that they were increased in one substrate and decreased in the other). The database provides a useful foundation for the approach of explaining silage preference by ruminants.

CONSORT 2010 statement: extension checklist for reporting within person randomised trials.

Evidence shows that the quality of reporting of randomised controlled trials (RCTs) is not optimal. The lack of transparent reporting impedes readers from judging the reliability and validity of trial findings and researchers from extracting information for systematic reviews and results in research waste. The Consolidated Standards of Reporting Trials (CONSORT) statement was developed to improve the reporting of RCTs. Within person trials are used for conditions that can affect two or more body sites, and are a useful and efficient tool because the comparisons between interventions are within people. Such trials are most commonly conducted in ophthalmology, dentistry, and dermatology. The reporting of within person trials has, however, been variable and incomplete, hindering their use in clinical decision making and by future researchers. This document presents the CONSORT extension to within person trials. It aims to facilitate the reporting of these trials. It extends 16 items of the CONSORT 2010 checklist and introduces a modified flowchart and baseline table to enhance transparency. Examples of good reporting and evidence based rationale for CONSORT within person checklist items are provided.

Neutrophilic superoxide production can assess pharmacological and pharmacogenetic ß-adrenoreceptor effects.

Asthma can be controlled well in most patients by inhaled ß-adrenoreceptor (ß2 AR) agonists and steroids. Poor response to ß2 AR agonists is difficult to predict, especially in young children and by lung function testing, which may be affected by multiple influences. As an alternative approach, we analyzed ex vivo neutrophilic superoxide inhibition in response to ß2 AR stimulation. In 60 healthy volunteers, this assay was unaffected by sex, age, smoking, atopy or asthma status. Furthermore, we assessed effects of genetic variants in ß2 AR by sequencing the ADRB2 gene in our cohort and relating genotypes to ß2 AR-mediated neutrophilic superoxide inhibition. Gly16Arg genotypes correlated with minor decrease in overall adrenoresponse in this small study population. Taken together, ex vivo testing of the ß2 AR response in human neutrophils represents a robust tool with good signal-to-noise ratio at physiological ß2 AR agonist concentrations, and this assay may be useful to complement future pharmacogenetic studies in asthma.

Obliquity-paced Pliocene West Antarctic ice sheet oscillations.

Thirty years after oxygen isotope records from microfossils deposited in ocean sediments confirmed the hypothesis that variations in the Earth's orbital geometry control the ice ages, fundamental questions remain over the response of the Antarctic ice sheets to orbital cycles. Furthermore, an understanding of the behaviour of the marine-based West Antarctic ice sheet (WAIS) during the 'warmer-than-present' early-Pliocene epoch ( approximately 5-3 Myr ago) is needed to better constrain the possible range of ice-sheet behaviour in the context of future global warming. Here we present a marine glacial record from the upper 600 m of the AND-1B sediment core recovered from beneath the northwest part of the Ross ice shelf by the ANDRILL programme and demonstrate well-dated, approximately 40-kyr cyclic variations in ice-sheet extent linked to cycles in insolation influenced by changes in the Earth's axial tilt (obliquity) during the Pliocene. Our data provide direct evidence for orbitally induced oscillations in the WAIS, which periodically collapsed, resulting in a switch from grounded ice, or ice shelves, to open waters in the Ross embayment when planetary temperatures were up to approximately 3 degrees C warmer than today and atmospheric CO(2) concentration was as high as approximately 400 p.p.m.v. (refs 5, 6). The evidence is consistent with a new ice-sheet/ice-shelf model that simulates fluctuations in Antarctic ice volume of up to +7 m in equivalent sea level associated with the loss of the WAIS and up to +3 m in equivalent sea level from the East Antarctic ice sheet, in response to ocean-induced melting paced by obliquity. During interglacial times, diatomaceous sediments indicate high surface-water productivity, minimal summer sea ice and air temperatures above freezing, suggesting an additional influence of surface melt under conditions of elevated CO(2).

Bortezomib Treatment can Overcome Glucocorticoid Resistance in Childhood B-cell Precursor Acute Lymphoblastic Leukemia Cell Lines.

BACKGROUND: The response to initial glucocorticoid (gc) treatment is a reliable stratification factor in childhood acute lymphoblastic leukemia (ALL) and may predict the response to multi-agent chemotherapy. In a former study we detected that the valosin-containing protein (VCP, cdc48), a member of the ubiquitin proteasome degradation system (UPS), is altered in gc-resistant leukemic cells suggesting that the associated pathways might be involved in chemotherapy resistance in childhood ALL. METHODS: Human B-cell precursor leukemia cell lines, gc-resistant MHH-cALL-2 and gc-sensitive MHH-cALL-3, were treated with prednisolone and various concentrations of bortezomib. Viability and apoptosis rates were determined. RESULTS: Both cell lines showed a dose-dependent increase in caspase activity after bortezomib single treatment. The gc-sensitive cells showed an additive effect after combined treatment with prednisolone and bortezomib. In contrast, both cell lines showed a reduced viability and enhanced propidium iodide positivity after combined treatment as determined by flow cytometry. Western blot analyses of poly-(ADP-ribose) polymerase 1 (PARP-1) suggested that combined treatment promote necrotic cleavage of PARP-1 in gc-resistant cells. Furthermore, after prednisolone treatment the UPS associated proteins VCP and NFκB-inhibitor IκBα were differentially modulated in gc-resistant cells. CONCLUSIONS: The proteasome inhibitor bortezomib seems to sensitize gc-resistant childhood ALL cells for prednisolone-induced cell death.

Hsa-mir-124-3 CpG island methylation is associated with advanced tumours and disease recurrence of patients with clear cell renal cell carcinoma.

BACKGROUND: Whether methylation of the microRNA (mir)-124-3 CpG island is of relevance for the clinical course of a solid cancer and whether it shows association with clinicopathology or survival of patients with renal cell cancer (RCC) is not known as yet. METHODS: In a cross-sectional study, relative methylation of mir-124-3 was measured in 111 RCC samples and 77 paired normal appearing tissues using quantitative methyl-specific PCR. Results were statistically compared with tumour histology, clinicopathological parameters and disease recurrence. RESULTS: We found tumour-specific hypermethylation of mir-124-3 in samples of RCCs with clear cell histology (ccRCC) compared with paired normal appearing tissues (P<0.0001). Methylation was significantly increased in tumours with state of advanced disease (P<0.0001). Higher relative methylation was associated with worse recurrence-free survival in both univariate (hazard ratio=9.37; P=0.0005) as well as bivariate Cox regression analyses considering age, sex, diameter of tumours and state of advanced disease, metastasis and lymph node metastases as covariates (hazard ratios=5.9-18.2; P-values of 0.0003-0.008). CONCLUSION: We identified mir-124-3 CpG islands (CGI) methylation as a relevant epigenetic mark for ccRCC thus underlining the need for functional studies of potentially affected signalling pathways in kidney tumour models. Methylation of mir-124-3 is suggested as an independent prognosticator for ccRCC.

Measurement of the N170 during facial neuromuscular electrical stimulation (fNMES).

BACKGROUND: Studies on facial feedback effects typically employ props or posed facial expressions, which often lack temporal precision and muscle specificity. NEW METHOD: Facial Neuromuscular Electrical Stimulation (fNMES) allows for a controlled influence of contractions of facial muscles, and may be used to advance our understanding of facial feedback effects, especially when combined with Electroencephalography (EEG). However, electrical stimulation introduces significant interference that can mask underlying brain dynamics. Whether established signal processing methods can allow for a reduction of said interference whilst retaining effects of interest, remains unexplored. RESULTS: We addressed these questions focusing on the classic N170 visual evoked potential, a face-sensitive brain component: 20 participants viewed images of houses, and of sad, happy, and neutral faces. On half of the trials, fNMES was delivered to bilateral lower-face muscles during the presentation of visual stimuli. A larger N170 amplitude was found for faces relative to houses. Interestingly, this was the case both without and during fNMES, regardless of whether the fNMES artefact was removed or not. Moreover, sad facial expressions elicited a larger N170 amplitude relative to neutral facial expressions, both with and without fNMES. COMPARISON WITH EXISTING METHODS: fNMES offers a more precise way of manipulating proprioceptive feedback from facial muscles, which affords greater diversity in experimental design for studies on facial feedback effects. CONCLUSIONS: We show that the combining of fNMES and EEG can be achieved and may serve as a powerful means of exploring the impact of controlled proprioceptive inputs on various types of cognitive processing.

Plant stem cell extract from Coffea canephora shows antioxidant, anti-inflammatory, and skin regenerative properties mediated by suppression of nuclear factor-κB.

Plant cell cultures have become a promising production platform of bioactive compounds for biomedical and cosmetic uses in the last decades. However, the success so far has been limited. The study aimed to evaluate the effectiveness of this unique biotechnology process to obtain a bioactive stem cell extract of Coffea canephora (SCECC) with antioxidant, anti-inflammatory, and regenerative properties. Total phenolic and flavonoid contents were determined in the SCECC by spectrophotometry. The chemical composition of the extracts was characterized by mass spectrometry. Antioxidant activity was evaluated using the colorimetric methods of free radical scavenging 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and the ferric reducing ability of plasma (FRAP). The anti-inflammatory activity was determined in lipopolysaccharide-stimulated RAW 264.7 macrophages through the production of superoxide anion (O2•-), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and the activity of nuclear factor kappa B (NF-κB). Moreover, the ability of SCECC to stimulate the proliferation and migration of fibroblasts was assessed. Five compounds were tentatively identified, two flavonoids, two phenolic acids, and one sugar. High phenolic content and antioxidant activity were observed in the SCECC. SCECC promoted the proliferation and migration of fibroblasts and suppressed the pro-inflammatory mediators O2•-, NO, TNF-α, and IL-6 in a dose-dependent manner. Moreover, SCECC inhibited the NF-κB transcription factor. Therefore, we obtained evidence that the extract from C. canephora stem cells can be used as a natural agent against skin damage. Hence, it could be of interest in cosmetics for preventing skin aging.

High gamma mapping using EEG.

High gamma (HG) power changes during motor activity, especially at frequencies above 70 Hz, play an important role in functional cortical mapping and as control signals for BCI (brain-computer interface) applications. Most studies of HG activity have used ECoG (electrocorticography) which provides high-quality spatially localized signals, but is an invasive method. Recent studies have shown that non-invasive modalities such as EEG and MEG can also detect task-related HG power changes. We show here that a 27 channel EEG (electroencephalography) montage provides high-quality spatially localized signals non-invasively for HG frequencies ranging from 83 to 101 Hz. We used a generic head model, a weighted minimum norm least squares (MNLS) inverse method, and a self-paced finger movement paradigm. The use of an inverse method enables us to map the EEG onto a generic cortex model. We find the HG activity during the task to be well localized in the contralateral motor area. We find HG power increases prior to finger movement, with average latencies of 462 ms and 82 ms before EMG (electromyogram) onset. We also find significant phase-locking between contra- and ipsilateral motor areas over a similar HG frequency range; here the synchronization onset precedes the EMG by 400 ms. We also compare our results to ECoG data from a similar paradigm and find EEG mapping and ECoG in good agreement. Our findings demonstrate that mapped EEG provides information on two important parameters for functional mapping and BCI which are usually only found in HG of ECoG signals: spatially localized power increases and bihemispheric phase-locking.

STARR with Contour Transtar: prospective multicentre European study.

OBJECTIVE: The stapled transanal rectal resection (STARR) in patients with defecation disorders is limited by the shape and capacity of the circular stapler. A new device has been recently developed, the Contour Transtar stapler, in order to improve the safety and effectiveness of the STARR technique. The study has been designed to confirm this declaration. METHOD: From January to June 2007 a prospective European multicentre study of consecutive patients with defecation disorder caused by internal rectal prolapse underwent the new STARR technique. The assessment of perioperative morbidity and functional outcome after 6 weeks, 3 and 12 months was documented by different scores. RESULTS: In all 75 patients, median age 64, the Transtar procedure was performed with 9% intraoperative difficulties, 7% postoperative complications and no mortality. The mean reduction of the ODS score was -15.6 (95%-CI: -17.3 to -13.8, P < 0.0001), mean reduction of SSS was -12.6 (95%-CI: -14.2 to -11.2; P < 0.0001). 41% stated improvement of their continence status by CCF score, only 4 patients (5%) had deterioration. CONCLUSION: The Transtar procedure is technically demanding, with good functional results similar to the conventional STARR.

Innovative technique for the closure of rectovaginal fistula using Surgisis mesh.

BACKGROUND: The aim of this prospective study was to analyse the efficacy of Surgisis mesh for closure of rectovaginal fistulas. Prospective data were collected from two centres. METHODS: All patients with a rectovaginal fistula who underwent definitive surgery using Surgisis mesh were prospectively enrolled in this study. Inclusion criteria included a rectovaginal fistula in the lower two-thirds of the rectovaginal septum. Surgery was performed with a standardized technique including combined transrectal and transvaginal excision of the rectovaginal fistula with transvaginal placement of the mesh. Success was defined as closure of both internal and external (perianal and vaginal) openings, absence of drainage without further intervention, and no abscess formation. RESULTS: Over a period of 16 months, a total of 21 mesh procedures were performed in two centres. The mean age of the patients was 47 years (18-59 years). Of the 21 patients, 18 (86%) had recurrent rectovaginal fistula, and the mean number of prior attempts was 2.3 (0-8). The majority of patients (nine) had Crohn's disease-associated fistula, followed by six with iatrogenic fistula, two with radiation-induced fistula, two with obstetric injury-induced fistula, and two with idiopathic fistula. The mesh procedure was performed under faecal diversion in eight patients (38%). The mean operative time was 38 min; no intraoperative morbidity occurred. Patients were discharged from hospital on day 4. After a mean follow-up of 12 months (range, 3-18 months), the overall success rate after primary mesh procedure was 71% (15/21; 6 patients had failure or recurrence). All patients with failure or recurrence were reoperated upon. Out of these six patients who were reoperated upon, four had definite healing (75%). Among the eight patients who had faecal diversion, four (50%) had reversal of their stoma. CONCLUSION: The preliminary success rate for this innovative technique using Surgisis mesh for the closure of rectovaginal fistulas is promising. Further studies are needed to assess the definite role of this novel technique in comparison to traditional surgical procedures.

Fatty acid composition of vegetable oil blend and in vitro effects of pharmacotherapeutical skin care applications.

Vegetable oils have been used for a plethora of health benefits by their incorporation in foods, cosmetics, and pharmaceutical products, especially those intended for skin care. This study aimed to investigate the cutaneous benefits of a vegetable oil blend (VOB) formulation and its fatty acid composition. The anti-inflammatory activity was studied in macrophages of RAW 264.7 cells by investigating the release of nitric oxide (NO), superoxide anion generation (O2-), tumor necrosis factor-alpha (TNF-α), and interleukin 6 (IL-6). ABTS cation radical scavenging capacity assay, ferric reducing antioxidant potential (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and NO free radical scavenging assays were used to evaluate the antioxidant activity. VOB was tested for its ability to stimulate fibroblast proliferation and migration using the scratch assay, and antibacterial activity by the microdilution test. The fatty acid profile of a freshly prepared VOB formulation was determined by gas chromatography before and after accelerated stability testing. Chemical composition of VOB revealed the presence of oleic acid (C18:1n-9; 63.3%), linoleic acid (C18:2n-6; 4.7%), and linolenic acid (C18:3n-6; 5.1%) as major mono- and polyunsaturated fatty acids. No changes in the organoleptic characteristics and fatty acid composition were observed after the accelerated stability test. VOB 100 µg/mL reduced the healing time by increasing the total number of cells in the wounded area by 43.0±5.1% compared to the negative control group. VOB also suppressed the pro-inflammatory TNF-α and IL-6 cytokines, and NO and O2- production in lipopolysaccharide-stimulated macrophage cells. In conclusion, the VOB formulation contributed to the improvement of current therapeutic strategies for cutaneous applications in skin care.

Short-lived brain state after cued motor imagery in naive subjects.

Multi-channel electroencephalography recordings have shown that a visual cue, indicating right hand, left hand or foot motor imagery, can induce a short-lived brain state in the order of about 500 ms. In the present study, 10 able-bodied subjects without any motor imagery experience (naive subjects) were asked to imagine the indicated limb movement for some seconds. Common spatial filtering and linear single-trial classification was applied to discriminate between two conditions (two brain states: right hand vs. left hand, left hand vs. foot and right hand vs. foot). The corresponding classification accuracies (mean +/- SD) were 80.0 +/- 10.6%, 83.3 +/- 10.2% and 83.6 +/- 8.8%, respectively. Inspection of central mu and beta rhythms revealed a short-lasting somatotopically specific event-related desynchronization (ERD) in the upper mu and/or beta bands starting approximately 300 ms after the cue onset and lasting for less than 1 s.

Plant stem cell extract from Coffea canephora shows antioxidant, anti-inflammatory, and skin regenerative properties mediated by suppression of nuclear factor-κB

Plant cell cultures have become a promising production platform of bioactive compounds for biomedical and cosmetic uses in the last decades. However, the success so far has been limited. The study aimed to evaluate the effectiveness of this unique biotechnology process to obtain a bioactive stem cell extract of Coffea canephora (SCECC) with antioxidant, anti-inflammatory, and regenerative properties. Total phenolic and flavonoid contents were determined in the SCECC by spectrophotometry. The chemical composition of the extracts was characterized by mass spectrometry. Antioxidant activity was evaluated using the colorimetric methods of free radical scavenging 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and the ferric reducing ability of plasma (FRAP). The anti-inflammatory activity was determined in lipopolysaccharide-stimulated RAW 264.7 macrophages through the production of superoxide anion (O2•-), nitric oxide (NO), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and the activity of nuclear factor kappa B (NF-κB). Moreover, the ability of SCECC to stimulate the proliferation and migration of fibroblasts was assessed. Five compounds were tentatively identified, two flavonoids, two phenolic acids, and one sugar. High phenolic content and antioxidant activity were observed in the SCECC. SCECC promoted the proliferation and migration of fibroblasts and suppressed the pro-inflammatory mediators O2•-, NO, TNF-α, and IL-6 in a dose-dependent manner. Moreover, SCECC inhibited the NF-κB transcription factor. Therefore, we obtained evidence that the extract from C. canephora stem cells can be used as a natural agent against skin damage. Hence, it could be of interest in cosmetics for preventing skin aging.

Cross-disciplinarity in the advance of Antarctic ecosystem research.

The biodiversity, ecosystem services and climate variability of the Antarctic continent and the Southern Ocean are major components of the whole Earth system. Antarctic ecosystems are driven more strongly by the physical environment than many other marine and terrestrial ecosystems. As a consequence, to understand ecological functioning, cross-disciplinary studies are especially important in Antarctic research. The conceptual study presented here is based on a workshop initiated by the Research Programme Antarctic Thresholds - Ecosystem Resilience and Adaptation of the Scientific Committee on Antarctic Research, which focussed on challenges in identifying and applying cross-disciplinary approaches in the Antarctic. Novel ideas and first steps in their implementation were clustered into eight themes. These ranged from scale problems, through risk maps, and organism/ecosystem responses to multiple environmental changes and evolutionary processes. Scaling models and data across different spatial and temporal scales were identified as an overarching challenge. Approaches to bridge gaps in Antarctic research programmes included multi-disciplinary monitoring, linking biomolecular findings and simulated physical environments, as well as integrative ecological modelling. The results of advanced cross-disciplinary approaches can contribute significantly to our knowledge of Antarctic and global ecosystem functioning, the consequences of climate change, and to global assessments that ultimately benefit humankind.

A fully automated correction method of EOG artifacts in EEG recordings.

OBJECTIVE: A fully automated method for reducing EOG artifacts is presented and validated. METHODS: The correction method is based on regression analysis and was applied to 18 recordings with 22 channels and approx. 6 min each. Two independent experts scored the original and corrected EEG in a blinded evaluation. RESULTS: The expert scorers identified in 5.9% of the raw data some EOG artifacts; 4.7% were corrected. After applying the EOG correction, the expert scorers identified in another 1.9% of the data some EOG artifacts, which were not recognized in the uncorrected data. CONCLUSIONS: The advantage of a fully automated reduction of EOG artifacts justifies the small additional effort of the proposed method and is a viable option for reducing EOG artifacts. The method has been implemented for offline and online analysis and is available through BioSig, an open source software library for biomedical signal processing. SIGNIFICANCE: Visual identification and rejection of EOG-contaminated EEG segments can miss many EOG artifacts, and is therefore not sufficient for removing EOG artifacts. The proposed method was able to reduce EOG artifacts by 80%.

Self-initiation of EEG-based brain-computer communication using the heart rate response.

Self-initiation, that is the ability of a brain-computer interface (BCI) user to autonomously switch on and off the system, is a very important issue. In this work we analyze whether the respiratory heart rate response, induced by brisk inspiration, can be used as an additional communication channel. After only 20 min of feedback training, ten healthy subjects were able to self-initiate and operate a 4-class steady-state visual evoked potential-based (SSVEP) BCI by using one bipolar ECG and one bipolar EEG channel only. Threshold detection was used to measure a beat-to-beat heart rate increase. Despite this simple method, during a 30 min evaluation period on average only 2.9 non-intentional switches (heart rate changes) were detected.

Study of on-line adaptive discriminant analysis for EEG-based brain computer interfaces.

A study of different on-line adaptive classifiers, using various feature types is presented. Motor imagery brain computer interface (BCI) experiments were carried out with 18 naive able-bodied subjects. Experiments were done with three two-class, cue-based, electroencephalogram (EEG)-based systems. Two continuously adaptive classifiers were tested: adaptive quadratic and linear discriminant analysis. Three feature types were analyzed, adaptive autoregressive parameters, logarithmic band power estimates and the concatenation of both. Results show that all systems are stable and that the concatenation of features with continuously adaptive linear discriminant analysis classifier is the best choice of all. Also, a comparison of the latter with a discontinuously updated linear discriminant analysis, carried out in on-line experiments with six subjects, showed that on-line adaptation performed significantly better than a discontinuous update. Finally a static subject-specific baseline was also provided and used to compare performance measurements of both types of adaptation.

Handsearching versus electronic searching to identify reports of randomized trials.

BACKGROUND: Systematic reviewers need to decide how best to reduce bias in identifying studies for their review. Even when journals are indexed in electronic databases, it can still be difficult to identify all relevant studies reported in these journals. Over 1700 journals have been or are being handsearched within The Cochrane Collaboration to identify reports of controlled trials in order to help address these problems. OBJECTIVES: To review systematically empirical studies, which have compared the results of handsearching with the results of searching one or more electronic databases to identify reports of randomized trials. SEARCH STRATEGY: Studies were sought from The Cochrane Methodology Register (The Cochrane Library, Issue 2, 2002), MEDLINE (1966 to Week 1 July 2002), EMBASE (1980 to Week 25 2002), AMED (1985 to June 2002), BIOSIS (1985 to June 2002), CINAHL (1982 to June 2002), LISA (1969 to July 2002) and PsycINFO (1972 to May 2002). Researchers who may have carried out relevant studies were contacted. SELECTION CRITERIA: A research study was considered eligible for this review if it compared handsearching with searching one or more electronic databases to identify reports of randomized trials. DATA COLLECTION AND ANALYSIS: The main outcome measure was the number of reports of randomized trials identified by handsearching as compared to electronic searching. Data were extracted on the electronic database searched, the complexity of electronic search strategy used, the characteristics of the journal reports identified, and the type of trial report identified. MAIN RESULTS: Thirty-four studies were included. Handsearching identified between 92% to 100% of the total number of reports of randomized trials found in the various comparisons in this review. Searching MEDLINE retrieved 55%, EMBASE 49% and PyscINFO 67%. The retrieval rate of the electronic database varied depending on the complexity of the search. The Cochrane Highly Sensitive Search Strategy (HSSS) identified 80% of the total number of reports of randomized trials found, searches categorised as 'complex' (including the Cochrane HSSS) found 65% and 'simple' found 42%. The retrieval rate for an electronic search was higher when the search was restricted to English language journals; 62% versus 39% for journals published in languages other than English. When the search was restricted to full reports of randomized trials, the retrieval rate for an electronic search improved: a complex search strategy (including the Cochrane HSSS) retrieved 82% of the total number of such reports of randomized trials. AUTHORS' CONCLUSIONS: Handsearching still has a valuable role to play in identifying reports of randomized trials for inclusion in systematic reviews of health care interventions, particularly in identifying trials reported as abstracts, letters and those published in languages other than English, together with all reports published in journals not indexed in electronic databases. However, where time and resources are limited, searching an electronic database using a complex search (or the Cochrane HSSS) will identify the majority of trials published as full reports in English language journals, provided, of course, that the relevant journals have been indexed in the database.