344 research outputs found
Modeling power corrections to the Bjorken sum rule for the neutrino structure function F_1
Direct measurements of the the structure functions F_1^{nu p} and F_1^{nu n}
at a neutrino factory would allow for an accurate extraction of alpha_s from
the Q^2-dependence of the Bjorken sum rule, complementing that based on the
Gross-Llewellyn-Smith sum rule for F_3. We estimate the power (1/Q^2-)
corrections to the Bjorken sum rule in the instanton vacuum model. For the
reduced matrix element of the flavor-nonsinglet twist-4 operator
ubar_g_Gdual_gamma_gamma5_u - (u -> d) we obtain a value of 0.18 GeV^2, in good
agreement with the QCD sum rule calculations of Braun and Kolesnichenko. Our
result allows to reduce the theoretical error in the determination of alpha_s.Comment: 3 pages, 1 figure, uses iopart.cls. Proceedings of the 4th NuFact'02
Workshop "Neutrino Factories based on Muon Storage Rings", Imperial College,
London, July 1-6, 200
Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network
We have studied the performance of a new algorithm for electron/pion
separation in an Emulsion Cloud Chamber (ECC) made of lead and nuclear emulsion
films. The software for separation consists of two parts: a shower
reconstruction algorithm and a Neural Network that assigns to each
reconstructed shower the probability to be an electron or a pion. The
performance has been studied for the ECC of the OPERA experiment [1].
The separation algorithm has been optimized by using a detailed Monte
Carlo simulation of the ECC and tested on real data taken at CERN (pion beams)
and at DESY (electron beams). The algorithm allows to achieve a 90% electron
identification efficiency with a pion misidentification smaller than 1% for
energies higher than 2 GeV
Combined and single effects of pesticide carbaryl and toxic Microcystis aeruginosa on the life history of Daphnia pulicaria
The combined influence of a pesticide (carbaryl) and a cyanotoxin (microcystin LR) on the life history of Daphnia pulicaria was investigated. At the beginning of the experiments animals were pulse exposed to carbaryl for 24 h and microcystins were delivered bound in Microcystis’ cells at different, sub-lethal concentrations (chronic exposure). In order to determine the actual carbaryl concentrations in the water LC–MS/MS was used. For analyses of the cyanotoxin concentration in Daphnia’s body enzyme-linked immunosorbent assay (ELISA) was used. Individual daphnids were cultured in a flow-through system under constant light (16 h of light: 8 h of dark), temperature (20°C), and food conditions (Scenedesmus obliquus, 1 mg of C l−1). The results showed that in the treatments with carbaryl egg numbers per female did not differ significantly from controls, but the mortality of newborns increased significantly. Increasing microcystin concentrations significantly delayed maturation, reduced size at first reproduction, number of eggs, and newborns. The interaction between carbaryl and Microcystis was highly significant. Animals matured later and at a smaller size than in controls. The number of eggs per female was reduced as well. Moreover, combined stressors caused frequent premature delivery of offspring with body deformations such as dented carapax or an undeveloped heart. This effect is concluded to be synergistic and could not be predicted from the effects of the single stressors.
Neoadjuvant chemotherapy versus debulking surgery in advanced tubo-ovarian cancers: pooled analysis of individual patient data from the EORTC 55971 and CHORUS trials
Background: Individual patient data from two randomised trials comparing neoadjuvant chemotherapy with upfront debulking surgery in advanced tubo-ovarian cancer were analysed to examine long-term outcomes for patients and to identify any preferable therapeutic approaches for subgroup populations. Methods: We did a per-protocol pooled analysis of individual patient data from the European Organisation for Research and Treatment of Cancer (EORTC) 55971 trial (NCT00003636) and the Medical Research Council Chemotherapy Or Upfront Surgery (CHORUS) trial (ISRCTN74802813). In the EORTC trial, eligible women had biopsy-proven International Federation of Gynecology and Obstetrics (FIGO) stage IIIC or IV invasive epithelial tubo-ovarian carcinoma. In the CHORUS trial, inclusion criteria were similar to those of the EORTC trial, and women with apparent FIGO stage IIIA and IIIB disease were also eligible. The main aim of the pooled analysis was to show non-inferiority in overall survival with neoadjuvant chemotherapy compared with upfront debulking surgery, using the reverse Kaplan-Meier method. Tests for heterogeneity were based on Cochran's Q heterogeneity statistic. Findings: Data for 1220 women were included in the pooled analysis, 670 from the EORTC trial and 550 from the CHORUS trial. 612 women were randomly allocated to receive upfront debulking surgery and 608 to receive neoadjuvant chemotherapy. Median follow-up was 7·6 years (IQR 6·0–9·6; EORTC, 9·2 years [IQR 7·3–10·4]; CHORUS, 5·9 years [IQR 4·3–7·4]). Median age was 63 years (IQR 56–71) and median size of the largest metastatic tumour at diagnosis was 8 cm (IQR 4·8–13·0). 55 (5%) women had FIGO stage II–IIIB disease, 831 (68%) had stage IIIC disease, and 230 (19%) had stage IV disease, with staging data missing for 104 (9%) women. In the entire population, no difference in median overall survival was noted between patients who underwent neoadjuvant chemotherapy and upfront debulking surgery (27·6 months [IQR 14·1–51·3] and 26·9 months [12·7–50·1], respectively; hazard ratio [HR] 0·97, 95% CI 0·86–1·09; p=0·586). Median overall survival for EORTC and CHORUS patients was significantly different at 30·2 months (IQR 15·7–53·7) and 23·6 months (10·5–46·9), respectively (HR 1·20, 95% CI 1·06–1·36; p=0·004), but was not heterogeneous (Cochran's Q, p=0·17). Women with stage IV disease had significantly better outcomes with neoadjuvant chemotherapy compared with upfront debulking surgery (median overall survival 24·3 months [IQR 14·1–47·6] and 21·2 months [10·0–36·4], respectively; HR 0·76, 95% CI 0·58–1·00; p=0·048; median progression-free survival 10·6 months [7·9–15·0] and 9·7 months [5·2–13·2], respectively; HR 0·77, 95% CI 0·59–1·00; p=0·049). Interpretation: Long-term follow-up data substantiate previous results showing that neoadjuvant chemotherapy and upfront debulking surgery result in similar overall survival in advanced tubo-ovarian cancer, with better survival in women with stage IV disease with neoadjuvant chemotherapy. This pooled analysis, with long-term follow-up, shows that neoadjuvant chemotherapy is a valuable treatment option for patients with stage IIIC–IV tubo-ovarian cancer, particularly in patients with a high tumour burden at presentation or poor performance status
Electrochemical Biosensing of Algal Toxins in Water: The Current State-of-the-Art
Due to increasing stringency of water legislation and extreme consequences that failure to detect some contaminants in water can involve, there has been a strong interest in developing electrochemical biosensors for algal toxin detection during the past decade, evidenced by literature increasing from 2 journal papers pre-2009 to 24 between 2009 and 2018. In this context, this review has summarized recent progress of successful algal toxin detection in water using electrochemical biosensing techniques. Satisfactory detection recoveries using real environmental water samples and good sensor repeatability and reproducibility have been achieved, along with some excellent limit-of-detection (LOD) reported. Recent electrochemical biosensor literature in algal toxin detection is compared and discussed to cover three major design components: (1) biorecognition elements, (2) electrochemical read-out techniques, and (3) sensor electrodes and signal amplification strategy. The recent development of electrochemical biosensors has provided one more step further toward quick in situ detection of algal toxins in the contamination point of the water source. In the end, we have also critically reviewed the current challenges and research opportunities regarding electrochemical biosensors for algal toxin detection that need to be addressed before they attain commercial viability
Disturbance and stress - different meanings in ecological dynamics?
There is an increasing frequency of papers
addressing disturbance and stress in ecology without
clear delimitation of their meaning. Some authors
use the terms disturbance and stress exclusively as
impacts, while others use them for the entire process,
including both causes and effects. In some studies, the
disturbance is considered as a result of a temporary
impact, which is positive for the ecosystem, while
stress is a negative, debilitating impact. By developing
and testing simple theoretical models, the authors
propose to differentiate disturbance and stress by
frequency. If the frequency of the event enables the
variable to reach a dynamic equilibrium which might
be exhibited without this event, then the event (plus its
responses) is a disturbance for the system. If frequency
prevents the variable’s return to similar pre-event
dynamics and drives or shifts it to a new trajectory,
then we are facing stress. The authors propose that
changes triggered by the given stimuli can be evaluated
on an absolute scale, therefore, direction of change of the variable must not be used to choose one
term or the other, i.e. to choose between stress and
disturbance
Healthcare utilization patterns for knee and hip osteoarthritis before and after changes in national health insurance coverage:A data linkage study from the Netherlands
Introduction: Medical guidelines aim to stimulate stepped care for knee and hip osteoarthritis, redirecting treatments from hospitals to primary care. In the Netherlands, this development was supported by changing health insurance coverage for physio/exercise therapy. The aim of this study was to evaluate healthcare utilization patterns before and after health changes in health insurance coverage. Method: We analyzed electronic health records and claims data from patients with osteoarthritis in the knee (N =32,091) and hip (N = 16,313). Changes between 2013 and 2019 in the proportion of patients treated by the general practitioner, physio/exercise therapist or orthopedic surgeon within 6 months after onset were assessed. Results: Joint replacement surgeries decreased for knee (OR 0.47 [0.41–0.54]) and hip (OR 0.81 [0.71–0.93]) osteoarthritis between 2013–2019. The use of physio/exercise therapy increased (knee: OR 1.38 [1.24–1.53], hip: OR 1.26 [1.08–1.47]). However, the proportion treated by a physio/exercise therapist decreased for patients that had not depleted their annual deductibles (knee: OR 0.86 [0.79 – 0.94], hip: OR 0.90 [0.79 – 1.02]). This might be affected by the inclusion of physio/exercise therapy in basic health insurance in 2018. Conclusion:We have found a shift from hospitals to primary care in knee and hip osteoarthritis care. However, the use of physio/exercise therapy declined after changes in insurance coverage for patients that had not depleted their deductibles
IMPROVING CYANOBACTERIA AND CYANOTOXIN MONITORING IN SURFACE WATERS FOR DRINKING WATER SUPPLY
Neoadjuvant chemotherapy versus debulking surgery in advanced tubo-ovarian cancers: pooled analysis of individual patient data from the EORTC 55971 and CHORUS trials.
BACKGROUND: Individual patient data from two randomised trials comparing neoadjuvant chemotherapy with upfront debulking surgery in advanced tubo-ovarian cancer were analysed to examine long-term outcomes for patients and to identify any preferable therapeutic approaches for subgroup populations. METHODS: We did a per-protocol pooled analysis of individual patient data from the European Organisation for Research and Treatment of Cancer (EORTC) 55971 trial (NCT00003636) and the Medical Research Council Chemotherapy Or Upfront Surgery (CHORUS) trial (ISRCTN74802813). In the EORTC trial, eligible women had biopsy-proven International Federation of Gynecology and Obstetrics (FIGO) stage IIIC or IV invasive epithelial tubo-ovarian carcinoma. In the CHORUS trial, inclusion criteria were similar to those of the EORTC trial, and women with apparent FIGO stage IIIA and IIIB disease were also eligible. The main aim of the pooled analysis was to show non-inferiority in overall survival with neoadjuvant chemotherapy compared with upfront debulking surgery, using the reverse Kaplan-Meier method. Tests for heterogeneity were based on Cochran's Q heterogeneity statistic. FINDINGS: Data for 1220 women were included in the pooled analysis, 670 from the EORTC trial and 550 from the CHORUS trial. 612 women were randomly allocated to receive upfront debulking surgery and 608 to receive neoadjuvant chemotherapy. Median follow-up was 7·6 years (IQR 6·0-9·6; EORTC, 9·2 years [IQR 7·3-10·4]; CHORUS, 5·9 years [IQR 4·3-7·4]). Median age was 63 years (IQR 56-71) and median size of the largest metastatic tumour at diagnosis was 8 cm (IQR 4·8-13·0). 55 (5%) women had FIGO stage II-IIIB disease, 831 (68%) had stage IIIC disease, and 230 (19%) had stage IV disease, with staging data missing for 104 (9%) women. In the entire population, no difference in median overall survival was noted between patients who underwent neoadjuvant chemotherapy and upfront debulking surgery (27·6 months [IQR 14·1-51·3] and 26·9 months [12·7-50·1], respectively; hazard ratio [HR] 0·97, 95% CI 0·86-1·09; p=0·586). Median overall survival for EORTC and CHORUS patients was significantly different at 30·2 months (IQR 15·7-53·7) and 23·6 months (10·5-46·9), respectively (HR 1·20, 95% CI 1·06-1·36; p=0·004), but was not heterogeneous (Cochran's Q, p=0·17). Women with stage IV disease had significantly better outcomes with neoadjuvant chemotherapy compared with upfront debulking surgery (median overall survival 24·3 months [IQR 14·1-47·6] and 21·2 months [10·0-36·4], respectively; HR 0·76, 95% CI 0·58-1·00; p=0·048; median progression-free survival 10·6 months [7·9-15·0] and 9·7 months [5·2-13·2], respectively; HR 0·77, 95% CI 0·59-1·00; p=0·049). INTERPRETATION: Long-term follow-up data substantiate previous results showing that neoadjuvant chemotherapy and upfront debulking surgery result in similar overall survival in advanced tubo-ovarian cancer, with better survival in women with stage IV disease with neoadjuvant chemotherapy. This pooled analysis, with long-term follow-up, shows that neoadjuvant chemotherapy is a valuable treatment option for patients with stage IIIC-IV tubo-ovarian cancer, particularly in patients with a high tumour burden at presentation or poor performance status. FUNDING: National Cancer Institute and Vlaamse Liga tegen kanker (Flemish League against Cancer)
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