RSS-Based Sensor Localization in the Presence of Unknown Channel Parameters

This correspondence studies the received signal strength-based localization problem when the transmit power or path-loss exponent is unknown. The corresponding maximum-likelihood estimator (MLE) poses a difficult nonconvex optimization problem. To avoid the difficulty in solving the MLE, we use suitable approximations and formulate the localization problem as a general trust region subproblem, which can be solved exactly under mild conditions. Simulation results show a promising performance for the proposed methods, which also have reasonable complexities compared to existing approaches

RSS-based sensor localization with unknown transmit power

Received signal strength (RSS)-based single source localization when there is not a prior knowledge about the transmit power of the source is investigated. Because of nonconvex behavior of maximum likelihood (ML) estimator, convoluted computations are required to achieve its global minimum. Therefore, we propose a novel semidefinite programming (SDP) approach by approximating ML problem to a convex optimization problem which can be solved very efficiently. Computer simulations show that our proposed SDP has a remarkable performance very close to ML estimator. Linearizing RSS model, we also derive the partly novel least squares (LS) and weighted total least squares (WTLS) algorithms for this problem. Simulations illustrate that WTLS improves the performance of LS considerably

Bearing-only target localization with uncertainties in observer position

In this paper, the bearing-only target localization problem when the observer positions are subject to error is investigated. In this problem, the angle of arrival of the transmitted signal between target and observer are used to estimate the target position. It is assumed that not only the bearing measurements are corrupted by noise but also the exact position of observer is not available to the estimator. The accuracy of estimated location of target depends on the reliability of information from the observer position. Therefore, the previously published algorithms considering only the bearing measurement noise do not meet the expected performance when the observer positions are subject to error. The maximum likelihood, the least squares and total least square algorithms and a new method of localization based on weighted total least squares approach are developed for this problem. The corresponding Cram´er-Rao lower bound (CRLB) is derived for this problem. Computer simulations are performed to evaluate the performance of the proposed algorithms. Simulation results show that the new method can attain the CRLB for sufficiently high SNR

Pancreas divisum. Correlation between anatomical abnormalities and bile precipitation in the gallbladder in seven patients

Pancreas divisum is a genetic defect associated with recurrent acute pancreatitis due to insufficient drainage of the accessory pancreatic duct. Seven young patients diagnosed with pancreatic divisum and thickening of the gallbladder bile as shown on magnetic resonance cholangio-pancreatography without pancreatic ductal changes underwent laparoscopic cholecystectomy. During the mean follow-up of 32 months no episode of pancreatitis was reported. There is an association between PD and higher concentration of bile in the gallbladder. Cholecystectomy can be considered curative in patients with PD in the absence of indications for major surgery

Rational Design of an Epitope-Based Hepatitis C Virus Vaccine

Despite improving treatment methods and therapeutic options, hepatitis C virus (HCV) remains a major global disease burden, and a vaccine would help greatly in reducing its incidence. Due to its extremely high sequence variability, HCV can readily escape the immune response, thus a vaccine must elicit an immune response toward conserved, functionally important epitopes. Using structural data of the broadly neutralizing antibody HCV1 in complex with a conserved linear epitope from the HCV E2 protein (aa 412-423, referred to as epitope I or domain E), we performed structure-based design to generate vaccine immunogens to induce antibody responses to this epitope. Designs selected for immunological characterization included a stabilized minimal epitope structure based on a defensin protein, as well as a bivalent vaccine featuring two copies of epitope I on the E2 surface. In vivo studies confirmed that these designs successfully generated robust antibody responses to this epitope, and sera from vaccinated mice neutralized HCV. In addition to presenting several effective HCV vaccine immunogens, this study demonstrates that induction of neutralizing anti-HCV antibodies is possible using an epitope-based vaccine, providing the basis for further efforts in structure-based vaccine design to target this and other critical epitopes of HCV

APPLICATION OF MORPHO-ANATOMICAL TRAITS OF MAIZE PLANT TO QUALITY CONTROL AND QUALITY ASSURANCE IN MAIZE SEED SYSTEM

Good seed quality can be obtained through control of the entire seed production process. There are emerging issues in the seed sector due to seed quality in market. In many countries seed and planting materials available to farmers are often of insufficient quality, thus undermining the potential performance of crops. The objective this study was to use morpho-anatomical traits to determine the levels of maize hybrid seed purity on the market in Uganda. A total of 120 samples of four popular commercial maize hybrid were collected from agro-dealers in 13 districts, representing 3 seed companies\u2019 distribution network. The samples were planted and evaluated based on their descriptors, using an Alpha Lattice Design, with two replications at the National Crops Resources Research Institute (NaCRRI), Namulonge. Data were collected for 33 morpho-anatomical traits. Results showed significant (P<0.05) differences within hybrids, and sources of seed among districts. Among the test materials, only Longe 9H had no significant (P<0.05) difference within traits but others had some levels of significant (P<0.05) differences. The principal component analysis of quantitative traits resulted in four components for each variety, with the explanation total of 53.3% for Longe 6H, 51.1% for Longe 7H, and 92.8% for Longe 9H and 39.1% for Longe 10%. There were varying levels of contamination of commercial hybrids based on morphoanatomical traits diversity within hybrids, compared to their descriptors for the traits evaluated. Hence, there is need to strengthen the quality control sub-sector for improved productivity at farmer levels.Des semences de bonne qualit\ue9 peuvent \ueatre obtenues en exer\ue7ant un control syst\ue9matique sur chacun des maillons du syst\ue8me de production semenci\ue8re. Le secteur semencier conna\ueet de plus en plus de difficult\ue9s, et ceci en raison de la qualit\ue9 des semences sur le march\ue9. Dans plusieurs pays, les semences disponibles pour les producteurs sont souvent de qualit\ue9 non satisfaisante, reduisant ainsi la performance des cultures. L\u2019objectif de l\u2019\ue9tude \ue9tait de se servir des caract\ue8res morpho-anatomiques afin de determiner le niveau purit\ue9 des semences de ma\uefs hybride sur le march\ue9 semencier en Ouganda. Au total 120 \ue9chantillons des quatre vari\ue9t\ue9es commerciales populaires de ma\uefs hybride ont \ue9t\ue9 collect\ue9s chez les distributeurs de semences dans 13 districts, repr\ue9sentant les r\ue9seaux de distribution de 3 compagnies semenci\ue8res. Les \ue9chantillons ont \ue9t\ue9 sem\ue9s et \ue9valu\ue9s en se basant sur leurs descripteurs. Le dispositive exp\ue9rimental Alpha Lattice a \ue9t\ue9 utilis\ue9, avec deux r\ue9p\ue9titions \ue0 l\u2019institut national de recherche des ressources culturales (NaCRRI), Namulonge. Les donn\ue9es de 33 caract\ue8res morphoanatomiques ont \ue9t\ue9 collect\ue9es. Les r\ue9sultats ont montr\ue9 des differences significatives (P<0,05) ont \ue9t\ue9 observ\ue9es parmi les hybrides, ainsi que les sources des semences au sein des districts. Parmi les mat\ue9riels test\ue9s, seul Longe 9H n\u2019avait exhib\ue9 aucune difference significative (P<0,05) des caract\ue8res \ue9valu\ue9s, mais certains ont des differences significatives \ue0 (P<0,05). l\u2019analyse en composntes principales des traits quantitatifs a montr\ue9 quatre composantes pour chaque vari\ue9t\ue9, avec l\u2019ensemble de ces composantes expliquant 53,3% de la variation totale pour Longe 6H, 51,1% pour Longe 7H, 92,8% pour Longe 9H et 39,1% pour Longe 10%. Les niveaux de contamination \ue9taient variables, sugg\ue9rant la n\ue9cessit\ue9 de renforcer le sous-secteur de control de qualit\ue9 en vue d\u2019une meilleure productivit\ue9 au niveau des producteurs

Structure-Based Design of Hepatitis C Virus Vaccines That Elicit Neutralizing Antibody Responses to a Conserved Epitope

Despite recent advances in therapeutic options, hepatitis C virus (HCV) remains a severe global disease burden, and a vaccine can substantially reduce its incidence. Due to its extremely high sequence variability, HCV can readily escape the immune response; thus, an effective vaccine must target conserved, functionally important epitopes. Using the structure of a broadly neutralizing antibody in complex with a conserved linear epitope from the HCV E2 envelope glycoprotein (residues 412 to 423; epitope I), we performed structure-based design of immunogens to induce antibody responses to this epitope. This resulted in epitope-based immunogens based on a cyclic defensin protein, as well as a bivalent immunogen with two copies of the epitope on the E2 surface. We solved the X-ray structure of a cyclic immunogen in complex with the HCV1 antibody and confirmed preservation of the epitope conformation and the HCV1 interface. Mice vaccinated with our designed immunogens produced robust antibody responses to epitope I, and their serum could neutralize HCV. Notably, the cyclic designs induced greater epitope-specific responses and neutralization than the native peptide epitope. Beyond successfully designing several novel HCV immunogens, this study demonstrates the principle that neutralizing anti-HCV antibodies can be induced by epitope-based, engineered vaccines and provides the basis for further efforts in structure-based design of HCV vaccines. IMPORTANCE: Hepatitis C virus is a leading cause of liver disease and liver cancer, with approximately 3% of the world\u27s population infected. To combat this virus, an effective vaccine would have distinct advantages over current therapeutic options, yet experimental vaccines have not been successful to date, due in part to the virus\u27s high sequence variability leading to immune escape. In this study, we rationally designed several vaccine immunogens based on the structure of a conserved epitope that is the target of broadly neutralizing antibodies. In vivo results in mice indicated that these antigens elicited epitope-specific neutralizing antibodies, with various degrees of potency and breadth. These promising results suggest that a rational design approach can be used to generate an effective vaccine for this virus

The inherent tensions within sustainable supply chains: a case study from Bangladesh

The complexities surrounding the supply chain logistics for perishable commodities within Bangladesh are extensive. Poor infrastructure, fragmented transportation and corruption compound the operational complexities within this emerging market. This case study analyses many of the day-to-day operational challenges and tensions inherent within Micro-Small-Medium Enterprises (MSMEs) forming the backbone of the Bangladesh socio-economic structure. The drive for transition toward greater levels of sustainability and corporate responsibility is problematic, affecting many levels within an extended and fragmented supply chain. The selected case study highlights the “lived in” geographical, environmental, economic and cultural factors that impact the ability of emerging market enterprises to remain profitable within emergency scenarios whilst transitioning toward a more sustainable model. This study, whilst detailing many of the tensions and critical issues facing MSMEs, highlights the benefits of direct Government intervention, criticality of a leaner and more efficient supply chain and reassessment of financial incentives to drive the transition to a more efficient and sustainable economy

Experiences of dementia in a foreign country: qualitative content analysis of interviews with people with dementia

Background: Dementia is a worldwide health concern of epidemic proportions. Research in the field of subjective experience of dementia suffers from a lack of diversity of their participants including immigrants. Different portraits of life with dementia could help us understand how people with dementia conceptualise their experiences of dementia and how they live. Our study aimed to explore the subjective experiences of living with dementia among Iranian immigrants in Sweden. Methods: Qualitative content analysis of interviews with fifteen people with dementia from Iranian immigrant backgrounds were conducted (8 females and 7 males). Results: Three themes and seven associated sub-themes were revealed. The themes included: Being a person with dementia means living with forgetfulness (personal sphere), living with forgetfulness in the private sphere means feeling incompetent but still loved, living with forgetfulness in the public sphere means feeling confident and secure but also isolated. Conclusions: Living with dementia for the participants meant living with forgetfulness. They experienced feeling incompetent but still loved within their families and feeling confident and secure but also isolated in the society. Educating people with dementia and their families about the course and process of dementia may help them understand the changes better and adjust their expectations. Our study can provide a basis for healthcare workers to understand the experiences of living with dementia from this specific perspective