125 research outputs found

    On Optimal Control at the Onset of a New Viral Outbreak

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    An optimal control problem for the early stage of an infectious disease outbreak is considered. At that stage, control is often limited to non-medical interventions like social distancing and other behavioral changes. We show that the running cost of control satisfying mild, problem-specific, conditions generates an optimal control strategy that stays inside its admissible set for the entire duration of the study period [0,T][0 ,T]. For the optimal control problem, restricted by SIR compartmental model of disease transmission, we prove that the optimal control strategy, u(t)u(t), may be growing until some moment tˉ[0,T)\bar{t} \in [0 ,T). However, for any t[tˉ,T]t \in [\bar{t}, T], the function u(t)u(t) will decline as tt approaches TT, which may cause the number of newly infected people to increase. So, the window from 00 to tˉ\bar{t} is the time for public health officials to prepare alternative mitigation measures, such as vaccines, testing, antiviral medications, and others. Our theoretical findings are illustrated with numerical examples showing optimal control strategies for various cost functions and weights. Simulation results provide a comprehensive demonstration of the effects of control on the epidemic spread and mitigation expenses, which can serve as invaluable references for public health officials

    In awe of God, nature and technology : a lexical approach to the differentiation of emotional responses

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    This article investigates typical usage patterns of the word awe in the English language and how it is related to psychology to depict specific lexical representation of emotions. Contextual analysis of the corpus data revealed inconsistencies in the lexicographic description of awe, regarded by most dictionaries as monosemous. Using linguistic tools of analysis, a functional classification of awe experiences in English-speaking culture was created in the form of a dictionary entry for the word awe. The analysis demonstrates that awe has a threefold sense structure based on two major distinctions: 1) evaluative attitudes of the perceiving self (ambivalent, positive, negative) and 2) vastness of perceived stimulus (transcendental vs mundane). The established collocational patterns suggest that cases exist of purely negative transcendence described by the word awe as it is largely overlooked by modern psychological studies because of prescriptive research designs. Therefore, the descriptive tools of lexical analysis might better be considered for improved differentiation of the emotional states as highlighted in typical collocational patterns of natural language

    Example of two different potentials which have practically the same fixed-energy phase shifts

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    It is shown that the Newton-Sabatier procedure for inverting the fixed-energy phase shifts for a potential is not an inversion method but a parameter-fitting procedure. Theoretically there is no guarantee that this procedure is applicable to the given set of the phase shifts, if it is applicable, there is no guaran- tee that the potential it produces generates the phase shifts from which it was reconstructed. Moreover, no generic potential, specifically, no potential which is not analytic in a neighborhood of the positive real semiaxis can be reconstructed by the Newton-Sabatier procedure. A numerical method is given for finding spherically symmetric compactly supported potentials which produce practically the same set of fixed-energy phase shifts for all values of angular momentum. Concrete example of such potentials is given

    On deconvolution problems: numerical aspects

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    An optimal algorithm is described for solving the deconvolution problem of the form ku:=0tk(ts)u(s)ds=f(t){\bf k}u:=\int_0^tk(t-s)u(s)ds=f(t) given the noisy data fδf_\delta, ffδδ.||f-f_\delta||\leq \delta. The idea of the method consists of the representation k=A(I+S){\bf k}=A(I+S), where SS is a compact operator, I+SI+S is injective, II is the identity operator, AA is not boundedly invertible, and an optimal regularizer is constructed for AA. The optimal regularizer is constructed using the results of the paper MR 40#5130.Comment: 7 figure

    Effect of the mineral-biological preparation Glauxin on the intensity of the development of the test culture of Lettuce (Lactuca sativa)

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    To ensure the safety of the drugs being developed and their guaranteed effectiveness, large-scale experiments using sufficient groups and types of test objects are required. The composition of the studied preparation, which includes the main representatives of rhizospheric microorganisms sorbed on mineral sorbent, allows us to judge its environmental safety. At the same time, the preparations offered for organic farming should have sufficient effectiveness, stimulating the growth and development of cultivated plants. The article presents the results of an experimental study and analyzes the effect of the mineral-biological drug Glauxin on the intensity of development of a test culture – Lettuce variety «Vostorg». The formed groups of experience and control, and identical growing conditions made it possible to obtain objective data, and the number of test objects in the groups (n=50) was sufficient for statistical processing of the results obtained. To obtain the most complete picture of the effect of the drug being developed, observations were carried out for 60 days, which exceeds the productive period of this culture by 15 days. To determine the most effective ways of using the drug Glauxin, two treatment schemes were applied to the tested plants: with soaking of seeds and without pre-soaking, using the studied drug only when watering and spraying. The results obtained indicate a high stimulating activity of the drug, allow us to judge its safety, because in the recommended modes of use they do not cause physiological changes and violations of the development of the test culture of lettuce. Based on the results obtained, conclusions were drawn about the most effective method of using the mineral-biological drug Glauxin, statistical data processing will allow us to draw conclusions about the economic efficiency of its use on an industrial scale

    Gene amplification in human cells knocked down for RAD54

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    Background: In mammalian cells gene amplification is a common manifestation of genome instability promoted by DNA double-strand breaks (DSBs). The repair of DSBs mainly occurs through two mechanisms: non-homologous end-joining (NHEJ) and homologous recombination (HR). We previously showed that defects in the repair of DSBs via NHEJ could increase the frequency of gene amplification. In this paper we explored whether a single or a combined defect in DSBs repair pathways can affect gene amplification. Results: We constructed human cell lines in which the expression of RAD54 and/or DNA-PKcs was constitutively knocked-down by RNA interference. We analyzed their radiosensitivity and their capacity to generate amplified DNA. Our results showed that both RAD54 and DNA-PKcs deficient cells are hypersensitive to γ-irradiation and generate methotrexate resistant colonies at a higher frequency compared to the proficient cell lines. In addition, the analysis of the cytogenetic organization of the amplicons revealed that isochromosome formation is a prevalent mechanism responsible for copy number increase in RAD54 defective cells. Conclusions: Defects in the DSBs repair mechanisms can influence the organization of amplified DNA. The high frequency of isochromosome formation in cells deficient for RAD54 suggests that homologous recombination proteins might play a role in preventing rearrangements at the centromeres

    Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

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    A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

    The Baltimore declaration toward the exploration of organoid intelligence

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    We, the participants of the First Organoid Intelligence Workshop - "Forming an OI Community" (22-24 February 2022), call on the international scientific community to explore the potential of human brain-based organoid cell cultures to advance our understanding of the brain and unleash new forms of biocomputing while recognizing and addressing the associated ethical implications. The term "organoid intelligence" (OI) has been coined to describe this research and development approach (1) in a manner consistent with the term "artificial intelligence" (AI) - used to describe the enablement of computers to perform tasks normally requiring human intelligence. OI has the potential for diverse and far-reaching applications that could benefit humankind and our planet, and which urge the strategic development of OI as a collaborative scientific discipline. OI holds promise to elucidate the physiology of human cognitive functions such as memory and learning. It presents game-changing opportunities in biological and hybrid computing that could overcome significant limitations in silicon-based computing. It offers the prospect of unparalleled advances in interfaces between brains and machines. Finally, OI could allow breakthroughs in modeling and treating dementias and other neurogenerative disorders that cause an immense and growing disease burden globally. Realizing the world-changing potential of OI will require scientific breakthroughs. We need advances in human stem cell technology and bioengineering to recreate brain architectures and to model their potential for pseudo-cognitive capabilities. We need interface breakthroughs to allow us to deliver input signals to organoids, measure output signals, and employ feedback mechanisms to model learning processes. We also need novel machine learning, big data, and AI technologies to allow us to understand brain organoids
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