79 research outputs found

    Team decision theory of switched static and dynamic systems

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    This dissertation considers the decentralized control of switched linear systems with parameter dependent cost and system matrices. This problem class is investigated under a number of different formulations of player information structure, performance criteria and switching architecture. Such decentralized switched systems can be encountered in various applications like network control, control in a changing environment, economic theory, power systems, decision making in organizations, resource allocation. The thesis is roughly divided into three parts. The first part of the thesis focuses on the static quadratic team problem, where players observe partial observations of an underlying random state and generate actions with the objective of minimizing the expected value of a common quadratic cost function in the player actions. One of the motivations behind studying this problem is to solve a static stochastic-parameter problem useful in solving dynamic switched control problems encountered later. The problem however is studied in full generality and an operator theoretic framework is presented to analyze the same. We prove that a scheme where strategies are updated by sequentially applying the best responses of players, converges to the team optimal strategy. Such an update scheme provides a mechanism to numerically compute arbitrarily close approximations of the team optimal strategy. It also acts as a tool for validating structure of the team optimal strategy which can be beneficial in some cases for analytical computation of these strategies. The second part of the thesis considers dynamic switched optimal control problems with quadratic cost and players having local parameter knowledge. One of these problems is studied under full state feedback and i.i.d. parameter; the remaining two problems are output feedback, distinguished by the type of information structure: partially nested and one-step delayed sharing. For the former output feedback problem, parameters and measurements follow a partially nested structure with the parameters possibly being correlated across all stages. For the latter case, parameters are assumed to be Markov processes, with their values along with measurements available instantaneously to local controllers, but with a one time step delay to others. The solution to all these problems rely on the optimal solution to a static (one-stage) stochastic-parameter problem with local parameter dependent Gaussian measurements, and for this purpose the static quadratic team problem, examined in first part is used. The strategies obtained in all these dynamic problems are affine in the measurements with the parameter dependent coefficients obtained by solving a set of linear equations. These equations are immediately solvable when the total number of parameter values is finite. However, for the case of infinite parameter values, the update scheme examined in the first section also provides a mechanism to determine an approximation to the team optimal strategy. In the final part of the thesis, we consider a setup with switched linear nested plant whose system matrices switch between a finite number of values, with transitions in time governed by a finite state automaton. A linear nested controller is sought with corresponding system matrices dependent on a finite path history of the plant’s system matrices in order to stabilize the plant and achieve a desired level of l2-induced norm performance. The nested structures of both plant and controller are characterized by block lower-triangular system matrices with compatible dimensions. For this setup, exact conditions are provided for the existence of a finite path dependent synthesis. These include conditions for the completion of scaling matrices obtained through an extended matrix completion lemma. When individual controller dimensions are chosen at least as large as the plant, these conditions reduce to a set of linear matrix inequalities. The completion lemma also provides an algorithm to complete the closed loop scaling matrices leading to inequalities for controller synthesis

    Extreme conservation of noncoding DNA near HoxD complex of vertebrates

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    BACKGROUND: Homeotic gene complexes determine the anterior-posterior body axis in animals. The expression pattern and function of hox genes along this axis is colinear with the order in which they are organized in the complex. This 'chromosomal organization and functional correspondence' is conserved in all bilaterians investigated. Genomic sequences covering the HoxD complex from several vertebrate species are now available. This offers a comparative genomics approach to identify conserved regions linked to this complex. Although the molecular basis of 'colinearity' of Hox complexes is not yet understood, it is possible that there are control elements within or in the proximity of these complexes that establish and maintain the expression patterns of hox genes in a coordinated fashion. RESULTS: We have compared DNA sequence flanking the HoxD complex of several primate, rodent and fish species. This analysis revealed an unprecedented conservation of non-coding DNA sequences adjacent to the HoxD complex from fish to human. Stretches of hundreds of base pairs in a 7 kb region, upstream of HoxD complex, show 100% conservation across the vertebrate species. Using PCR primers from the human sequence, these conserved regions could be amplified from other vertebrate species, including other mammals, birds, reptiles, amphibians and fish. Our analysis of these sequences also indicates that starting from the conserved core regions, more sequences have been added on and maintained during evolution from fish to human. CONCLUSION: Such a high degree of conservation in the core regions of this 7 kb DNA, where no variation occurred during ~500 million years of evolution, suggests critical function for these sequences. We suggest that such sequences are likely to provide molecular handle to gain insight into the evolution and mechanism of regulation of associated gene complexes

    A clinical trial of treatment of uncomplicated typhoid fever: efficacy of ceftriaxone-azithromycin combination

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    Background: Typhoid fever is a systemic infection caused by Gram-negative bacterium Salmonella enterica serovar typhi (S. typhi). It is a major health problem in India. It carries significant morbidity and mortality. Antimicrobial therapy is critical for the management of typhoid fever. Emergence of multidrug-resistant (MDR) and nalidixic acid-resistant (NAR) strains of S. typhi has complicated therapy by limiting treatment options. Hence, this study was conducted to evaluate the efficacy and safety profile of ceftriaxone and azithromycin combination therapy in uncomplicated typhoid fever.Methods: Adults patients of blood culture proven uncomplicated typhoid fever admitted in the medicine ward of Teerthanker Mahaveer Medical College and Research Centre were treated with ceftriaxone intravenously (2 g daily for 14 days) and azithromycin orally (500 mg daily for 7 days). Patients were clinically and bacteriologically evaluated during the study period and follow-up.Results: 96% cure rate was observed. No relapse was recorded.Conclusion: Ceftriaxone-azithromycin combination may be considered as an empirical therapy for treatment of uncomplicated typhoid fever in view of the emergence of MDR and NAR strains of S. typhi

    Bio-Based PLA Membranes for Ion Transport and Ion Filtration

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    Lithium-ion batteries require battery separators for both safety and electrochemical performance. Due to that, they have received a lot of attention. In order to prevent any electronic current from moving within the negative and positive electrodes and allow ions to flow through while avoidance of electric contact between them, a porous membrane used as a separator is positioned between the electrodes with opposing polarities. Accordingly, the objective of the present work is to build a biodegradable PLA based battery separator, which has exceptional thermal capabilities and can endure temperatures of up to 300°C. They also seem to serve as the least degree of barrier for the flow of an ionic current. In this study bio-polymer battery separator membranes were developed using PLA as matrix material and fillers such as Copper slag (CS) and Cardanol resin (CNSL). CS and CNSL were preferred for the reason to realize the concept of a wealth reclaimed from wastes that act as toughening and pore forming agent for PLA matrix. It is found that at PLA-CS film has more brittleness when compared to neat PLA and PLA-CNSL resin. On the other hand, PLA-CNSL films are the toughest ones. Overall, it has been demonstrated that obtaining more sustainable and high-performance is possible by the usage of such sustainable materials for futuristic developments

    Optimization of state-of-the-art fuzzy-metaheuristic ANFIS-based machine learning models for flood susceptibility prediction mapping in the Middle Ganga Plain, India

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    CRediT authorship contribution statement: Dr. Aman Arora and Dr. Alireza Arabameri have conceptualized the study, prepared the dataset, and optimized the models. Dr. Manish Pandey has helped in writing the manuscript. Prof. Masood A. Siddiqui, Prof. U.K. Shukla, Prof. Dieu Tien Bui, Dr. Varun Narayan Mishra, and Dr. Anshuman Bhardwaj have helped in improving the manuscript at different stages of this work.Peer reviewedPostprin

    IL10 variant g.5311A is associated with Visceral Leishmaniasis in Indian population

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    Background: Visceral Leishmaniasis (VL) is a multifactorial disease, where the host genetics play a significant role in determining the disease outcome. The immunological role of anti-inflammatory cytokine, Interleukin 10 (IL10), has been well-documented in parasite infections and considered as a key regulatory cytokine for VL. Although VL patients in India display high level of IL10 in blood serum, no genetic study has been conducted to assess the VL susceptibility/resistance. Therefore, the aim of this study is to investigate the role of IL10 variations in Indian VL; and to estimate the distribution of disease associated allele in diverse Indian populations. Methodology: All the exons and exon-intron boundaries of IL10 were sequenced in 184 VL patients along with 172 ethnically matched controls from VL endemic region of India. Result and Discussion: Our analysis revealed four variations; rs1518111 (2195 A>G, intron), rs1554286 (2607 C>T, intron), rs3024496 (4976 T>C, 3’ UTR) and rs3024498 (5311 A>G, 3’ UTR). Of these, a variant g.5311A is significantly associated with VL (χ2 = 18.87; p = 0.00001). In silico approaches have shown that a putative micro RNA binding site (miR-4321) is lost in rs3024498 mRNA. Further, analysis of the above four variations in 1138 individuals from 34 ethnic populations, representing different social and linguistic groups who are inhabited in different geographical regions of India, showed variable frequency. Interestingly, we have found, majority of the tribal populations have low frequency of VL (‘A’ of rs3024498); and high frequency of leprosy (‘T’ of rs1554286), and Behcet’s (‘A’ of rs1518111) associated alleles, whereas these were vice versa in castes. Our findings suggest that majority of tribal populations of India carry the protected/less severe allele against VL, while risk/more severe allele for leprosy and Behcet’s disease. This study has potential implications in counseling and management of VL and other infectious diseases

    Association of Ficolin-2 serum levels and FCN2 genetic variants with Indian Visceral Leishmaniasis

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    Background: Visceral leishmaniasis (VL), one of the neglected tropical diseases, is endemic in the Indian subcontinent. Ficolins are circulating serum proteins of the lectin complement system and involved in innate immunity. Methods: We have estimated ficolin-2 serum levels and analyzed the functional variants of the encoding gene FCN2 in 218 cases of VL and in 225 controls from an endemic region of India. Results: Elevated levels of serum ficolin-2 were observed in VL cases compared to the controls (adjusted P<0.0001). The genetic analysis revealed that the FCN2 structural variant +6359 C>T (p.T236M) was associated with VL (OR=2.2, 95% CI = 1.23-7.25, P = 0.008) and with high ficolin-2 serum levels. We also found that the FCN2*AAAC haplotype occurred more frequently among healthy controls when compared to cases (OR = 0.59, 95% CI = 0.37-0.94, P = 0.023). Conclusions: Our findings indicate that the FCN2 variant +6359C>T is associated with the occurrence of VL and that ficolin-2 serum levels are elevated in Leishmania infections

    Genetic and functional evaluation of the role of CXCR1 and CXCR2 in susceptibility to visceral leishmaniasis in north-east India.

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    BACKGROUND: IL8RA and IL8RB, encoded by CXCR1 and CXCR2, are receptors for interleukin (IL)-8 and other CXC chemokines involved in chemotaxis and activation of polymorphonuclear neutrophils (PMN). Variants at CXCR1 and CXCR2 have been associated with susceptibility to cutaneous and mucocutaneous leishmaniasis in Brazil. Here we investigate the role of CXCR1/CXCR2 in visceral leishmaniasis (VL) in India. METHODS: Three single nucleotide polymorphisms (SNPs) (rs4674259, rs2234671, rs3138060) that tag linkage disequilibrium blocks across CXCR1/CXCR2 were genotyped in primary family-based (313 cases; 176 nuclear families; 836 individuals) and replication (941 cases; 992 controls) samples. Family- and population-based analyses were performed to look for association between CXCR1/CXCR2 variants and VL. Quantitative RT/PCR was used to compare CXCR1/CXCR2 expression in mRNA from paired splenic aspirates taken before and after treatment from 19 VL patients. RESULTS: Family-based analysis using FBAT showed association between VL and SNPs CXCR1_rs2234671 (Z-score = 2.935, P = 0.003) and CXCR1_rs3138060 (Z-score = 2.22, P = 0.026), but not with CXCR2_rs4674259. Logistic regression analysis of the case-control data under an additive model of inheritance showed association between VL and SNPs CXCR2_rs4674259 (OR = 1.15, 95%CI = 1.01-1.31, P = 0.027) and CXCR1_rs3138060 (OR = 1.25, 95%CI = 1.02-1.53, P = 0.028), but not with CXCR1_rs2234671. The 3-locus haplotype T_G_C across these SNPs was shown to be the risk haplotype in both family- (TRANSMIT; P = 0.014) and population- (OR = 1.16, P = 0.028) samples (combined P = 0.002). CXCR2, but not CXCR1, expression was down regulated in pre-treatment compared to post-treatment splenic aspirates (P = 0.021). CONCLUSIONS: This well-powered primary and replication genetic study, together with functional analysis of gene expression, implicate CXCR2 in determining outcome of VL in India.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are
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