1,758 research outputs found

    Capabilities of dating of glazed ceramics with monochrome glaze

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    Excavations of Kazan Kremlin conducted in 1994-2005 yielded diverse material in the form of numerous fragments of monochrome glazed ceramics. The fragments of glazed dishware originate from layers dating back to various epochs starting with the Kazan Khanate and ending with the Post Medieval period. This article is concerned with the research of the chemical composition of the glaze and paste of ceramics dating back to the late Middle Ages. Natural scientific research has allowed to identify two primary types of glass-forming components - sodium and lead. Groups differing in the elemental composition of paste and glaze were identified as a result of statistical processing of the analytical data. This distribution significantly corresponds to dating of artefacts on the basis of their stratigraphic chronology and comparative morphological analysis. A comparison of the obtained materials allows to identify samples of glazed ceramics from the excavations of Kazan Kremlin with unknown or speculative dating.peer-reviewe

    Nonlocality of the NN interaction in an effective field theory

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    We investigate low energy nucleon dynamics in the effective field theory (EFT) of nuclear forces. In leading order of the two-nucleon EFT we show that nucleon dynamics is governed by the generalized dynamical equation with a nonlocal-in-time interaction operator. This equation is shown to open new possibilities for applying the EFT approach to the description of low energy nucleon dynamics.Comment: 13 pages, 4 figures, REVTeX

    Time Ordering in Kicked Qubits

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    We examine time ordering effects in strongly, suddenly perturbed two-state quantum systems (kicked qubits) by comparing results with time ordering to results without time ordering. Simple analytic expressions are given for state occupation amplitudes and probabilities for singly and multiply kicked qubits. We investigate the limit of no time ordering, which can differ in different representations.Comment: 26 pages, 5 figure

    Novel statistical approaches for non-normal censored immunological data: analysis of cytokine and gene expression data

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    Background: For several immune-mediated diseases, immunological analysis will become more complex in the future with datasets in which cytokine and gene expression data play a major role. These data have certain characteristics that require sophisticated statistical analysis such as strategies for non-normal distribution and censoring. Additionally, complex and multiple immunological relationships need to be adjusted for potential confounding and interaction effects. Objective: We aimed to introduce and apply different methods for statistical analysis of non-normal censored cytokine and gene expression data. Furthermore, we assessed the performance and accuracy of a novel regression approach in order to allow adjusting for covariates and potential confounding. Methods: For non-normally distributed censored data traditional means such as the Kaplan-Meier method or the generalized Wilcoxon test are described. In order to adjust for covariates the novel approach named Tobit regression on ranks was introduced. Its performance and accuracy for analysis of non-normal censored cytokine/gene expression data was evaluated by a simulation study and a statistical experiment applying permutation and bootstrapping. Results: If adjustment for covariates is not necessary traditional statistical methods are adequate for non-normal censored data. Comparable with these and appropriate if additional adjustment is required, Tobit regression on ranks is a valid method. Its power, type-I error rate and accuracy were comparable to the classical Tobit regression. Conclusion: Non-normally distributed censored immunological data require appropriate statistical methods. Tobit regression on ranks meets these requirements and can be used for adjustment for covariates and potential confounding in large and complex immunological datasets

    Social media use and impact during the holiday travel planning process

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    Through an empirical study among holiday travellers, residing in the Former Soviet Union Republics, this paper presents a comprehensive view of role and impact of social media on the whole holiday travel planning process: Before, during and after the trip, providing insights on usage levels, scope of use, level of influence and trust. Findings suggest that social media are predominantly used after holidays for experience sharing. It is also shown that there is a strong correlation between perceived level of influence from social media and changes made in holiday plans prior to final decisions. Moreover, it is revealed that user-generated content is perceived as more trustworthy when compared to official tourism websites, travel agents and mass media advertising

    Plasma therapy in atypical haemolytic uremic syndrome: lessons from a family with a factor H mutation

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    Whilst randomised control trials are undoubtedly the best way to demonstrate whether plasma exchange or infusion alone is the best first-line treatment for patients with atypical haemolytic uremic syndrome (aHUS), individual case reports can provide valuable information. To that effect, we have had the unique opportunity to follow over a 10-year period three sisters with aHUS associated with a factor H mutation (CFH). Two of the sisters are monozygotic twins. A similar natural evolution and response to treatment would be expected for the three patients, as they all presented with the same at-risk polymorphisms for CFH and CD46 and no identifiable mutation in either CD46 or CFI. Our report of different modalities of treatment of the initial episode and of three transplantations and relapses in the transplant in two of them, strongly suggest that intensive plasma exchange, both acutely and prophylactically, can maintain the long-term function of both native kidneys and allografts. In our experience, the success of plasma therapy is dependent on the use of plasma exchange as opposed to plasma infusion alone, the prolongation of daily plasma exchange after normalisation of haematological parameters followed by prophylactic plasma exchange, the use of prophylactic plasma exchange prior to transplantation and the use of prophylactic plasma exchange at least once a week posttransplant with immediate intensification of treatment if there are any signs of recurrence

    Recursive construction of perfect DNA molecules from imperfect oligonucleotides

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    Making faultless complex objects from potentially faulty building blocks is a fundamental challenge in computer engineering, nanotechnology and synthetic biology. Here, we show for the first time how recursion can be used to address this challenge and demonstrate a recursive procedure that constructs error-free DNA molecules and their libraries from error-prone oligonucleotides. Divide and Conquer (D&C), the quintessential recursive problem-solving technique, is applied in silico to divide the target DNA sequence into overlapping oligonucleotides short enough to be synthesized directly, albeit with errors; error-prone oligonucleotides are recursively combined in vitro, forming error-prone DNA molecules; error-free fragments of these molecules are then identified, extracted and used as new, typically longer and more accurate, inputs to another iteration of the recursive construction procedure; the entire process repeats until an error-free target molecule is formed. Our recursive construction procedure surpasses existing methods for de novo DNA synthesis in speed, precision, amenability to automation, ease of combining synthetic and natural DNA fragments, and ability to construct designer DNA libraries. It thus provides a novel and robust foundation for the design and construction of synthetic biological molecules and organisms

    Developing and implementing an integrated delirium prevention system of care:a theory driven, participatory research study

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    Background: Delirium is a common complication for older people in hospital. Evidence suggests that delirium incidence in hospital may be reduced by about a third through a multi-component intervention targeted at known modifiable risk factors. We describe the research design and conceptual framework underpinning it that informed the development of a novel delirium prevention system of care for acute hospital wards. Particular focus of the study was on developing an implementation process aimed at embedding practice change within routine care delivery. Methods: We adopted a participatory action research approach involving staff, volunteers, and patient and carer representatives in three northern NHS Trusts in England. We employed Normalization Process Theory to explore knowledge and ward practices on delirium and delirium prevention. We established a Development Team in each Trust comprising senior and frontline staff from selected wards, and others with a potential role or interest in delirium prevention. Data collection included facilitated workshops, relevant documents/records, qualitative one-to-one interviews and focus groups with multiple stakeholders and observation of ward practices. We used grounded theory strategies in analysing and synthesising data. Results: Awareness of delirium was variable among staff with no attention on delirium prevention at any level; delirium prevention was typically neither understood nor perceived as meaningful. The busy, chaotic and challenging ward life rhythm focused primarily on diagnostics, clinical observations and treatment. Ward practices pertinent to delirium prevention were undertaken inconsistently. Staff welcomed the possibility of volunteers being engaged in delirium prevention work, but existing systems for volunteer support were viewed as a barrier. Our evolving conception of an integrated model of delirium prevention presented major implementation challenges flowing from minimal understanding of delirium prevention and securing engagement of volunteers alongside practice change. The resulting Prevention of Delirium (POD) Programme combines a multi-component delirium prevention and implementation process, incorporating systems and mechanisms to introduce and embed delirium prevention into routine ward practices. Conclusions: Although our substantive interest was in delirium prevention, the conceptual and methodological strategies pursued have implications for implementing and sustaining practice and service improvements more broadly
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