578 research outputs found

    Optokinetic stimulation rehabilitation in preventing seasickness

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    SummaryObjectivesSeasickness occurs when traveling on a boat: symptoms such as vomiting are very disturbing and may be responsible for discontinuing travel or occupation and can become life-threatening. The failure of classical treatment to prevent seasickness has motivated this retrospective study exploring optokinetic stimulation in reducing these symptoms.Patients and methodsExperimental training of 75 sailors with optokinetic stimulation attempted to reduce seasickness manifestations and determine the factors that could predict accommodation problems.ResultsEighty percent of the trained subjects were able to return on board. No predictive factors such as sex, occupation, degree of illness, number of treatment sessions, time to follow-up, and age were found to influence training efficacy.ConclusionOptokinetic stimulation appears to be promising in the treatment of seasickness. Nevertheless, statistically significant results have yet to demonstrate its efficacy

    Inorganic chlorine partitioning in the summer lower stratosphere: Modeled and measured [ClONO_2]/[HCl] during POLARIS

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    We examine inorganic chlorine (Cl_y,) partitioning in the summer lower stratosphere using in situ ER-2 aircraft observations made during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) campaign. New steady state and numerical models estimate [ClONO_2]/[HCl] using currently accepted photochemistry. These models are tightly constrained by observations with OH (parameterized as a function of solar zenith angle) substituting for modeled HO_2 chemistry. We find that inorganic chlorine photochemistry alone overestimates observed [ClONO_2]/[HCl] by approximately 55–60% at mid and high latitudes. On the basis of POLARIS studies of the inorganic chlorine budget, [ClO]/[ClONO_2], and an intercomparison with balloon observations, the most direct explanation for the model-measurement discrepancy in Cl_y, partitioning is an error in the reactions, rate constants, and measured species concentrations linking HCl and ClO (simulated [ClO]/[HCl] too high) in combination with a possible systematic error in the ER-2 ClONO_2 measurement (too low). The high precision of our simulation (±15% 1σ for [ClONO_2]/[HCl], which is compared with observations) increases confidence in the observations, photolysis calculations, and laboratory rate constants. These results, along with other findings, should lead to improvements in both the accuracy and precision of stratospheric photochemical models

    Quantitative constraints on the atmospheric chemistry of nitrogen oxides: An analysis along chemical coordinates

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    In situ observations Of NO_2, NO, NO_y, ClONO_2, OH, O_3, aerosol surface area, spectrally resolved solar radiation, pressure and temperature obtained from the ER-2 aircraft during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) experiments are used to examine the factors controlling the fast photochemistry connecting NO and NO_2 and the slower chemistry connecting NO_x and HNO_3. Our analysis uses “chemical coordinates” to examine gradients of the difference between a model and precisely calibrated measurements to provide a quantitative assessment of the accuracy of current photochemical models. The NO/NO_2 analysis suggests that reducing the activation energy for the NO+O_3 reaction by 1.7 kJ/mol will improve model representation of the temperature dependence of the NO/NO_2 ratio in the range 215–235 K. The NO_x/HNO_3 analysis shows that systematic errors in the relative rate coefficients used to describe NO_x loss by the reaction OH + NO_2 → HNO_3 and by the reaction set NO_2 + O_3 → NO_3; NO_2 + NO_3 → N_(2)O_5; N_(2)O_5 + H_(2)O → 2HNO_3 are in error by +8.4% (+30/−45%) (OH+NO_2 too fast) in models using the Jet Propulsion Laboratory 1997 recommendations [DeMore et al., 1997]. Models that use recommendations for OH+NO2 and OH+HNO_3 based on reanalysis of recent and past laboratory measurements are in error by 1.2% (+30/−45%) (OH+NO_2 too slow). The +30%/−45% error limit reflects systematic uncertainties, while the statistical uncertainty is 0.65%. This analysis also shows that the POLARIS observations only modestly constrain the relative rates of the major NO_x production reactions HNO3 + OH → H_(2)O + NO_3 and HNO_3 + hÎœ → OH + NO_2. Even under the assumption that all other aspects of the model are perfect, the POLARIS observations only constrain the rate coefficient for OH+HNO_3 to a range of 65% around the currently recommended value

    Comparison of modeled and observed values of NO_2 and JNO_2 during the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) mission

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    Stratospheric measurements of NO, NO_(2), O_(3), ClO, and HO_(2) were made during spring, early summer, and late summer in the Arctic region during 1997 as part of the Photochemistry of Ozone Loss in the Arctic Region in Summer (POLARIS) field campaign. In the sunlit atmosphere, NO_(2) and NO are in steady state through NO2 photolysis and reactions involving O_(3), ClO, BrO, and HO_(2). By combining observations of O_(3), ClO, and HO_(2), observed and modeled values of the NO_(2) photolysis rate coefficient (JNO_(2)), and model estimates of BrO, several comparisons are made between steady state and measured values of both NO_(2) and JNO_(2). An apparent seasonal dependence in discrepancies between calculated and measured values was found; however, a source for this dependence could not be identified. Overall, the mean linear fits in the various comparisons show agreement within 19%, well within the combined uncertainties (±50 to 70%). These results suggest that photochemistry controlling the NO_(2)/NO abundance ratio is well represented throughout much of the sunlit lower stratosphere. A reduction in the uncertainty of laboratory determinations of the rate coefficient of NO + O_(3) → NO_(2) + O_(2) would aid future analyses of these or similar atmospheric observations

    A guide to writing systematic reviews of rare disease treatments to generate FAIR-compliant datasets: Building a Treatabolome

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    Background: Rare diseases are individually rare but globally affect around 6% of the population, and in over 70% of cases are genetically determined. Their rarity translates into a delayed diagnosis, with 25% of patients waiting 5 to 30 years for one. It is essential to raise awareness of patients and clinicians of existing gene and variant-specific therapeutics at the time of diagnosis to avoid that treatment delays add up to the diagnostic odyssey of rare diseases' patients and their families. Aims: This paper aims to provide guidance and give detailed instructions on how to write homogeneous systematic reviews of rare diseases' treatments in a manner that allows the capture of the results in a computer-accessible form. The published results need to comply with the FAIR guiding principles for scientific data management and stewardship to facilitate the extraction of datasets that are easily transposable into machine-actionable information. The ultimate purpose is the creation of a database of rare disease treatments ("Treatabolome") at gene and variant levels as part of the H2020 research project Solve-RD. Results: Each systematic review follows a written protocol to address one or more rare diseases in which the authors are experts. The bibliographic search strategy requires detailed documentation to allow its replication. Data capture forms should be built to facilitate the filling of a data capture spreadsheet and to record the application of the inclusion and exclusion criteria to each search result. A PRISMA flowchart is required to provide an overview of the processes of search and selection of papers. A separate table condenses the data collected during the Systematic Review, appraised according to their level of evidence. Conclusions: This paper provides a template that includes the instructions for writing FAIR-compliant systematic reviews of rare diseases' treatments that enables the assembly of a Treatabolome database that complement existing diagnostic and management support tools with treatment awareness data

    Blaming Active Volcanoes or Active Volcanic Blame? Volcanic Crisis Communication and Blame Management in the Cameroon

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    This chapter examines the key role of blame management and avoidance in crisis communication with particular reference to developing countries and areas that frequently experience volcanic episodes and disasters. In these contexts, the chapter explores a key paradox prevalent within crisis communication and blame management concepts that has been rarely tested in empirical terms (see De Vries 2004; BrĂ€ndström 2016a). In particular, the chapter examines, what it calls, the ‘paradox of frequency’ where frequency of disasters leads to twin dispositions for crisis framed as either: (i) policy failure (active about volcanic blame on others), where issues of blame for internal incompetency takes centre stage, and blame management becomes a focus of disaster managers, and/or: (ii) as event failure (in this case, the blaming of lack of external capacity on active volcanoes and thereby the blame avoidance of disaster managers). Put simply, the authors investigate whether perceptions of frequency itself is a major determinant shaping the existence, operation, and even perceived success of crisis communication in developing regions, and countries experiencing regular disaster episodes. The authors argue frequency is important in shaping the behaviour of disaster managers and rather ironically as part of crisis communication can shape expectations of community resilience and (non)-compliance. In order to explore the implications of the ‘paradox of frequency’ further, the chapter examines the case of the Cameroon, where volcanic activity and events have been regular, paying particular attention to the major disasters in 1986 (Lake Nyos Disaster - LND) and 1999 (Mount Cameroon volcanic eruption - MCE)

    Mathematical Properties of a New Levin-Type Sequence Transformation Introduced by \v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. I. Algebraic Theory

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    \v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la [J. Math. Phys. \textbf{44}, 962 - 968 (2003)] introduced in connection with the summation of the divergent perturbation expansion of the hydrogen atom in an external magnetic field a new sequence transformation which uses as input data not only the elements of a sequence {sn}n=0∞\{s_n \}_{n=0}^{\infty} of partial sums, but also explicit estimates {ωn}n=0∞\{\omega_n \}_{n=0}^{\infty} for the truncation errors. The explicit incorporation of the information contained in the truncation error estimates makes this and related transformations potentially much more powerful than for instance Pad\'{e} approximants. Special cases of the new transformation are sequence transformations introduced by Levin [Int. J. Comput. Math. B \textbf{3}, 371 - 388 (1973)] and Weniger [Comput. Phys. Rep. \textbf{10}, 189 - 371 (1989), Sections 7 -9; Numer. Algor. \textbf{3}, 477 - 486 (1992)] and also a variant of Richardson extrapolation [Phil. Trans. Roy. Soc. London A \textbf{226}, 299 - 349 (1927)]. The algebraic theory of these transformations - explicit expressions, recurrence formulas, explicit expressions in the case of special remainder estimates, and asymptotic order estimates satisfied by rational approximants to power series - is formulated in terms of hitherto unknown mathematical properties of the new transformation introduced by \v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. This leads to a considerable formal simplification and unification.Comment: 41 + ii pages, LaTeX2e, 0 figures. Submitted to Journal of Mathematical Physic

    Switch-maintenance gemcitabine after first-line chemotherapy in patients with malignant mesothelioma (NVALT19):an investigator-initiated, randomised, open-label, phase 2 trial

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    Background Almost all patients with malignant mesothelioma eventually have disease progression after first-line therapy. Previous studies have investigated maintenance therapy, but none has shown a great effect. We aimed to assess the efficacy and safety of switch-maintenance gemcitabine in patients with malignant mesothelioma without disease progression after first-line chemotherapy. Methods We did a randomised, open-label, phase 2 trial in 18 hospitals in the Netherlands (NVALT19). We recruited patients aged older than 18 years with unresectable malignant mesothelioma with no evidence of disease progression after at least four cycles of first-line chemotherapy (with platinum and pemetrexed), who had a WHO performance status of 0-2, adequate organ function, and measurable or evaluable disease. Exclusion criteria were active uncontrolled infection or severe cardiac dysfunction, serious disabling conditions, symptomatic CNS metastases, radiotherapy within 2 weeks before enrolment, and concomitant use of any other drugs under investigation. Patients were randomly assigned (1:1), using the minimisation method, to maintenance intravenous gemcitabine (1250 mg/m(2) on days 1 and 8, in cycles of 21 days) plus supportive care, or to best supportive care alone, until disease progression, unacceptable toxicity, serious intercurrent illness, patient request for discontinuation, or need for any other anticancer agent, except for palliative radiotherapy. A CT scan of the thorax or abdomen (or both) and pulmonary function tests were done at baseline and repeated every 6 weeks. The primary outcome was progression-free survival in the intention-to-treat population. Safety was analysed in all participants who received one or more doses of the study drug or had at least one visit for supportive care. Recruitment is now closed; treatment and follow-up are ongoing. This study is registered with the Netherlands Trial Registry, NTR4132/NL3847. Findings Between March 20, 2014, and Feb 27, 2019, 130 patients were enrolled and randomly assigned to gemcitabine plus supportive care (65 patients [50%]) or supportive care alone (65 patients [50%]). No patients were lost to follow-up; median follow-up was 36.5 months (95% CI 34.2 to not reached), and one patient in the supportive care group withdrew consent. Progression-free survival was significantly longer in the gemcitabine group (median 6.2 months [95% CI 4.6-8.7]) than in the supportive care group (3.2 months [2.8-4.1]; hazard ratio [HR] 0.48 [95% CI 0.33-0.71]; p=0.0002). The benefit was confirmed by masked independent central review (HR 0.49 [0.33-0.72]; p=0.0002). Grade 3-4 adverse events occurred in 33 ( 52%) of 64 patients in the gemcitabine group and in ten (16%) of 62 patients in the supportive care group. The most frequent adverse events were anaemia, neutropenia, fatigue or asthenia, pain, and infection in the gemcitabine group, and pain, infection, and cough or dyspnoea in the supportive care group. One patient (2%) in the gemcitabine group died, due to a treatment-related infection. Interpretation Switch-maintenance gemcitabine, after first-line chemotherapy, significantly prolonged progression-free survival compared with best supportive care alone, among patients with malignant mesothelioma. This study confirms the activity of gemcitabine in treating malignant mesothelioma

    Implementation of Novel Molecular Biomarkers for Non-small Cell Lung Cancer in the Netherlands:How to Deal With Increasing Complexity

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    The diagnostic landscape of non-small cell lung cancer (NSCLC) is changing rapidly with the availability of novel treatments. Despite high-level healthcare in the Netherlands, not all patients with NSCLC are tested with the currently relevant predictive tumor markers that are necessary for optimal decision-making for today's available targeted or immunotherapy. An expert workshop on the molecular diagnosis of NSCLC involving pulmonary oncologists, clinical chemists, pathologists, and clinical scientists in molecular pathology was held in the Netherlands on December 10, 2018. The aims of the workshop were to facilitate cross-disciplinary discussions regarding standards of practice, and address recent developments and associated challenges that impact future practice. This paper presents a summary of the discussions and consensus opinions of the workshop participants on the initial challenges of harmonization of the detection and clinical use of predictive markers of NSCLC. A key theme identified was the need for broader and active participation of all stakeholders involved in molecular diagnostic services for NSCLC, including healthcare professionals across all disciplines, the hospitals and clinics involved in service delivery, healthcare insurers, and industry groups involved in diagnostic and treatment innovations. Such collaboration is essential to integrate different technologies into molecular diagnostics practice, to increase nationwide patient access to novel technologies, and to ensure consensus-preferred biomarkers are tested
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