340 research outputs found

    Determining the probability of cyanobacterial blooms: the application of Bayesian networks in multiple lake systems

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    A Bayesian network model was developed to assess the combined influence of nutrient conditions and climate on the occurrence of cyanobacterial blooms within lakes of diverse hydrology and nutrient supply. Physicochemical, biological, and meteorological observations were collated from 20 lakes located at different latitudes and characterized by a range of sizes and trophic states. Using these data, we built a Bayesian network to (1) analyze the sensitivity of cyanobacterial bloom development to different environmental factors and (2) determine the probability that cyanobacterial blooms would occur. Blooms were classified in three categories of hazard (low, moderate, and high) based on cell abundances. The most important factors determining cyanobacterial bloom occurrence were water temperature, nutrient availability, and the ratio of mixing depth to euphotic depth. The probability of cyanobacterial blooms was evaluated under different combinations of total phosphorus and water temperature. The Bayesian network was then applied to quantify the probability of blooms under a future climate warming scenario. The probability of the "high hazardous" category of cyanobacterial blooms increased 5% in response to either an increase in water temperature of 0.8°C (initial water temperature above 24°C) or an increase in total phosphorus from 0.01 mg/L to 0.02 mg/L. Mesotrophic lakes were particularly vulnerable to warming. Reducing nutrient concentrations counteracts the increased cyanobacterial risk associated with higher temperatures

    Electron/pion separation with an Emulsion Cloud Chamber by using a Neural Network

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    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 e/πe/\pi 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

    Modeling power corrections to the Bjorken sum rule for the neutrino structure function F_1

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    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

    Neoadjuvant chemotherapy versus debulking surgery in advanced tubo-ovarian cancers: pooled analysis of individual patient data from the EORTC 55971 and CHORUS trials

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    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

    Revisiting consistency with random utility maximisation: theory and implications for practical work

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    While the paradigm of utility maximisation has formed the basis of the majority of applications in discrete choice modelling for over 40 years, its core assumptions have been questioned by work in both behavioural economics and mathematical psychology as well as more recently by developments in the RUM-oriented choice modelling community. This paper reviews the basic properties with a view to explaining the historical pre-eminence of utility maximisation and addresses the question of what departures from the paradigm may be necessary or wise in order to accommodate richer behavioural patterns. We find that many, though not all, of the behavioural traits discussed in the literature can be approximated sufficiently closely by a random utility framework, allowing analysts to retain the many advantages that such an approach possesses

    Electrochemical Biosensing of Algal Toxins in Water: The Current State-of-the-Art

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    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

    The long road to automated trucking: Insights from driver focus groups

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    With the rapid progress of automated driving technology, self-driving vehicles are on the horizon. In this study, we look at what is likely to be the first implementation of a form of automated driving on public roads, i.e., truck platooning, where virtually connected trucks drive at short headways to save fuel and associated emissions. With progressing technology, we may see platoons with drivers resting while being in the truck or even platoons in which not all trucks require drivers. Hence, platooning technology has a significant impact on the jobs of truck drivers. Driver acceptance of this emerg- ing technology is therefore an important factor in the implementation of platooning and, consequently, automated driving in general. In this study, we explore the range of per- spectives that exist among drivers by conducting focus groups in the Netherlands. These discussions indicate that drivers foresee that platooning will eventually become a reality but believe it will have a negative impact on the quality of their work and their job satisfaction

    Különböző országokból származó cianobaktérium populációk toxicitása

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    7 Microcystis és 2 Planktothrix toxintermelő cianobaktérium minta vizsgálatára került sor, melyek a Velencei tóból, Braziliából és Németországból származnak. A minták egy része a természetben gyűjtött biomassza, míg másik része törzsizolátum. A toxicitás detektálására Thamnotox kittet, patkány májsejtvonalat, egértesztet alkalmaztunk. Az eredményeket összevetettük a HPLC-s analízis eredményeivel, mely szerint a brazil mintákban microcystin LR forma, vagyis a legtoxikusabb variáns nem fordult elő. A magyar és német minták egyaránt tartalmazták mindhárom vizsgált microcystin formát (LR, RR, YR), azonban a magyar mintákban az LR forma koncentrációja egy nagyságrenddel nagyobb volt, mint a német mintákban. Toxicitásban a magyar és brazil minták mutattak hasonlóságot, bár a brazil minták nem tartalmaztak LR variánst, de az RR forma koncentrációja olyan magas volt (12,5 és 14,8 mg/g), hogy ez jelentkezett a hasonló toxicitásban. A német minták alacsonyabb toxicitása a kisebb toxintartalommal magyarázható. A korreláció a Thamnotox teszt eredmények és az egérteszt eredmények között igen szoros (r: 0,967), míg a teljes toxin koncentráció és az egérteszt között 0,473, ugyanígy a teljes toxin koncentráció és a Thamnotoxkit teszt között (r: 0,680) jóval gyengébb az összefüggés. Hasonló eredményre jutottunk a májsejtekre kifejtett toxikus hatással kapcsolatban is. A biomassza kivonatok toxikusabbnak tűnnek, mint az a microcystin tartalommal magyarázható lenne, tehát feltételezhető, hogy a már ismert toxinokon kívül más toxikus hatású vegyületekkel is kell számolnunk a cianobaktériumoknál
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