Uncertain Quality Research Articles

Augmenting Chinese hamster genome assembly by identifying regions of high confidence

Chinese hamster Ovary (CHO) cell lines are the dominant industrial workhorses for therapeutic recombinant protein production. The availability of genome sequence of Chinese hamster and CHO cells will spur further genome and RNA sequencing of producing cell lines. However, the mammalian genomes assembled using shot-gun sequencing data still contain regions of uncertain quality due to assembly errors. Identifying high confidence regions in the assembled genome will facilitate its use for cell engineering and genome engineering. We assembled two independent drafts of Chinese hamster genome by de novo assembly from shotgun sequencing reads and by re-scaffolding and gap-filling the draft genome from NCBI for improved scaffold lengths and gap fractions. We then used the two independent assemblies to identify high confidence regions using two different approaches. First, the two independent assemblies were compared at the sequence level to identify their consensus regions as "high confidence regions" which accounts for at least 78 % of the assembled genome. Further, a genome wide comparison of the Chinese hamster scaffolds with mouse chromosomes revealed scaffolds with large blocks of collinearity, which were also compiled as high-quality scaffolds. Genome scale collinearity was complemented with EST based synteny which also revealed conserved gene order compared to mouse. As cell line sequencing becomes more commonly practiced, the approaches reported here are useful for assessing the quality of assembly and potentially facilitate the engineering of cell lines.

Mapping ignorance: 300 years of collecting flowering plants in Africa

AbstractAimSpatial and temporal biases in species‐occurrence data can compromise broad‐scale biogeographical research and conservation planning. Although spatial biases have been frequently scrutinized, temporal biases and the overall quality of species‐occurrence data have received far less attention. This study aims to answer three questions: (1) How reliable are species‐occurrence data for flowering plants in Africa? (2) Where and when did botanical sampling occur in the past 300 years? (3) How complete are plant inventories for Africa?LocationAfrica.MethodsBy filtering a publicly available dataset containing 3.5 million records of flowering plants, we obtained 934,676 herbarium specimens with complete information regarding species name, date and location of collection. Based on these specimens, we estimated inventory completeness for sampling units (SUs) of 25 km × 25 km. We then tested whether the spatial distribution of well‐sampled SUs was correlated with temporal parameters of botanical sampling. Finally, we determined whether inventory completeness in individual countries was related to old or recently collected specimens.ResultsThirty‐one per cent of SUs contained at least one specimen, whereas only 2.4% of SUs contained a sufficient number of specimens to reliably estimate inventory completeness. We found that the location of poorly sampled areas remained almost unchanged for half a century. Moreover, there was pronounced temporal bias towards old specimens in South Africa, the country that holds half of the available data for the continent. There, high inventory completeness stems from specimens collected several decades ago.Main conclusionsDespite the increasing availability of species occurrence data for Africa, broad‐scale biogeographical research is still compromised by the uncertain quality and spatial and temporal biases of such data. To avoid erroneous inferences, the quality and biases in species‐occurrence data should be critically evaluated and quantified prior to use. To this end, we propose a quantification method based on inventory completeness using easily accessible species‐occurrence data.

Antibiotics for otitis media with effusion in children.

Otitis media with effusion (OME) is characterised by an accumulation of fluid in the middle ear behind an intact tympanic membrane, without the symptoms or signs of acute infection. Since most cases of OME will resolve spontaneously, only children with persistent middle ear effusion and associated hearing loss potentially require treatment. Previous Cochrane reviews have focused on the effectiveness of ventilation tube insertion, adenoidectomy, nasal autoinflation, antihistamines, decongestants and corticosteroids in OME. This review, focusing on the effectiveness of antibiotics in children with OME, is an update of a Cochrane review published in 2012. To assess the benefits and harms of oral antibiotics in children up to 18 years with OME. The Cochrane ENT Information Specialist searched the ENT Trials Register; Central Register of Controlled Trials (CENTRAL 2016, Issue 3); PubMed; Ovid EMBASE; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 14 April 2016. Randomised controlled trials comparing oral antibiotics with placebo, no treatment or therapy of unproven effectiveness in children with OME. We used the standard methodological procedures expected by Cochrane. Twenty-five trials (3663 children) were eligible for inclusion. Two trials did not report on any of the outcomes of interest, leaving 23 trials (3258 children) covering a range of antibiotics, participants, outcome measures and time points for evaluation. Overall, we assessed most studies as being at low to moderate risk of bias.We found moderate quality evidence (six trials including 484 children) that children treated with oral antibiotics are more likely to have complete resolution at two to three months post-randomisation (primary outcome) than those allocated to the control treatment (risk ratio (RR) 2.00, 95% confidence interval (CI) 1.58 to 2.53; number needed to treat to benefit (NNTB) 5). However, there is evidence (albeit of low quality; five trials, 742 children) indicating that children treated with oral antibiotics are more likely to experience diarrhoea, vomiting or skin rash (primary outcome) than those allocated to control treatment (RR 2.15, 95% CI 1.29 to 3.60; number needed to treat to harm (NNTH) 20).In respect of the secondary outcome of complete resolution at any time point, we found low to moderate quality evidence from five meta-analyses, including between two and 14 trials, of a beneficial effect of antibiotics, with a NNTB ranging from 3 to 7. Time periods ranged from 10 to 14 days to six months.In terms of other secondary outcomes, only two trials (849 children) reported on hearing levels at two to four weeks and found conflicting results. None of the trials reported data on speech, language and cognitive development or quality of life. Low quality evidence did not show that oral antibiotics were associated with a decrease in the rate of ventilation tube insertion (two trials, 121 children) or in tympanic membrane sequelae (one trial, 103 children), while low quality evidence indicated that children treated with antibiotics were less likely to have acute otitis media episodes within four to eight weeks (five trials, 1086 children; NNTB 18) and within six months post-randomisation (two trials, 199 children; NNTB 5). It should, however, be noted that the beneficial effect of oral antibiotics on acute otitis media episodes within four to eight weeks was no longer significant when we excluded studies with high risk of bias. This review presents evidence of both benefits and harms associated with the use of oral antibiotics to treat children up to 16 years with OME. Although evidence indicates that oral antibiotics are associated with an increased chance of complete resolution of OME at various time points, we also found evidence that these children are more likely to experience diarrhoea, vomiting or skin rash. The impact of antibiotics on short-term hearing is uncertain and low quality evidence did not show that oral antibiotics were associated with fewer ventilation tube insertions. Furthermore, we found no data on the impact of antibiotics on other important outcomes such as speech, language and cognitive development or quality of life.Even in situations where clear and relevant benefits of oral antibiotics have been demonstrated, these must always be carefully balanced against adverse effects and the emergence of bacterial resistance. This has specifically been linked to the widespread use of antibiotics for common conditions such as otitis media.

Art Fairs as a Medium for Branding Young and Emerging Artists: The Case of Frieze London

ABSTRACTWhile previous researchers have attempted to explain the uncertain quality of visual arts with reference to branding theory, they have overlooked the role of art fairs. Socio-cultural approaches to branding allow us to explore the function of intermediaries in valuing contemporary arts. This article aims to analyze the role of art fairs in the process of branding young and emerging artists. In particular, a prestigious art fair, Frieze London, serves as an instrumental case study for developing a systematic understanding of art fairs in terms of valuing and branding contemporary art.

Willingness to Pay for Solar Lanterns: Does the Trial Period Play a Role?

AbstractWhere electricity access is limited, solar lanterns are a viable and relatively inexpensive source of basic lighting for households. However, the creation of commercially viable business models for solar lanterns is difficult because the customers are poor and make decisions under tight liquidity constraints. To understand the economics of technology adoption in the case of solar lanterns, we conduct a field experiment on willingness to pay (WTP) for solar lanterns in rural Uttar Pradesh. Applying the Becker–DeGroot–Marschak method of eliciting WTP, we evaluate the ability of a trial period and postponed payment to increase sales. We find no evidence for the effectiveness of the trial period and only weak evidence for the positive effect of postponed payment. Overall, WTP for the product among the customers is low. There is no clear evidence for concerns about the uncertain quality of the product, liquidity constraints, or present‐bias. In this context, policies to subsidize very small solar lanterns would not correct a market failure, as people appear to have only a limited interest in the product.

Prise en compte de l’état des produits pour la planification de leur désassemblage

This paper adresses the problem of disassembly process planning taking into account the quality or states of the product to be disassembled. We propose an approach which is able to return the best disassembly level for a product considering the disassembly cost and the state of the product and/or the states of its subassemblies or components. The state of the product is represented using the concept of « Potentiel d’Utilisation Residuel (PUR) » which is assumed to be a Gaussian random variable with known truncated distribution. A stochastic program is proposed to model the problem with the objective of maximizing the disassembly process profit. The latter is calculated as the difference between the positive revenue generated by recovered parts and the costs of the disassembly tasks. The revenue of a recovered part is a function of PUR. The developed approach is tested on two example case studies from the literature to analyze the impact of uncertain product quality on its disassembly process planning.

A robust optimisation model for hybrid remanufacturing and manufacturing systems under uncertain return quality and market demand

In remanufacturing research, most researchers predominantly emphasised on the recovery of whole product (core) rather than at the component level due to its complexity. In contrast, this paper addresses the challenges to focus on remanufacturing through component recovery, so as to solve production planning problems of hybrid remanufacturing and manufacturing systems. To deal with the uncertainties of quality and quantity of product returns, the processing time of remanufacturing, remanufacturing costs, as well as market demands, a robust optimisation model was developed in this research and a case study was used to evaluate its effectiveness and efficiency. To strengthen this research, a sensitivity analysis of the uncertain parameters and the original equipment manufacturer’s (OEM’s) pricing strategy was also conducted. The research finding shows that the market demand volatility leads to a significant increase in the under fulfilment and a reduction in OEM’s profit. On the other hand, recovery cost reduction, as endogenous cost saving, encourages the OEM to produce more remanufactured products with the increase in market demand. Furthermore, the OEM may risk profit loss if they raise the price of new products, and inversely, they could gain more if the price of remanufactured products is raised.

Judgement devices and the evaluation of singularities: The use of performance ratings and narrative information to guide film viewer choice

The focus of this study is to examine how management accounting information is used in the evaluation of singularities. As highlighted by Karpik (2010), singularities represent everyday goods and services that are unique, multidimensional, incommensurable, and of uncertain quality. The paper draws on these underlying properties in investigating how they are evaluated. It does so in the realm of popular culture, a space in which singularities are a common feature, using the example of a particular social phenomenon—that is, the Internet Movie Database (IMDb). Through the conduct of netnographic and interview-based research, the study explores how management accounting tools embedded within IMDb play a role in shaping diverse social outcomes in relation to popular culture (in this case, the unpredictable and varying film choices of individuals). It further explores how these tools also become constitutive of the core functioning of innovative social phenomena such as IMDb, so as to direct and somehow provide a semblance of order to these social outcomes and the derivation of them. Findings indicate that while the evaluation of singularities such as films are driven by a reliance on quantitative measures, such as the ratings and rankings on IMDb, they also are derived through aligning individual personal interests with that of the ‘information provider’, for example the interests and tastes of reviewers on IMDb. In this respect, our case shows how the problematic nature of imperfect and conflicting performance information can be effectively overcome.

Selection of Avocado Plants Based on Fruit Characters, Fat Content, and Continual Harvest along The Year in West Java-Indonesia

Avocado ( Persea americana Mill.) belongs to Lauraceae family, is originated from lowland and highland tropical America region. Avocado plant was introduced to Indonesia in 1750 by Spanish. Fruit of avocado contains high unsaturated ( healthy) fat, protein, fiber, vitamins, minerals, and energy. Fruit of avocado can be eaten freshly, used as an additional ingredient cooking and material for cosmetics. Avocado fruits are available along the year in market cities of Indonesia but their fruits fluctuate in quantity and uncertain quality. It because the plants commonly come from seeds and grown in home-yards or small areas by small farmers. The purposes of this research were to evaluate and select some cultivars for parent plants that produce good fruit characters, high content of fat, and continual yield along the year. The research was started on January 2011 until 2013 for obtaining data, collecting avocado fruits and scions in West Java province, which is the biggest avocado fruit production in Indonesia. From 180 accessions of avocado fruits, there were 31 potential accessions for selecting good cultivars and 6 accessions of them (10, 5, 39, 48, 61, 123) were selected. The selected fruit character had scores 72 – 80 of maximum 100, fat content 9.78% – 20.57%, and harvest periods from January to December. These accessions as grafted plants have grown and propagated in our research station of the Indonesian Institute of Sciences (LIPI) in Cibinong for further study and for releasing to the farmers.

An Integrated Multiechelon Logistics Model with Uncertain Delivery Lead Time and Quality Unreliability

Nowadays, in order to achieve advantages in supply chain management, how to keep inventory in adequate level and how to enhance customer service level are two critical practices for decision makers. Generally, uncertain lead time and defective products have much to do with inventory and service level. Therefore, this study mainly aims at developing a multiechelon integrated just-in-time inventory model with uncertain lead time and imperfect quality to enhance the benefits of the logistics model. In addition, the Ant Colony Algorithm (ACA) is established to determine the optimal solutions. Moreover, based on our proposed model and analysis, the ACA is more efficient than Particle Swarm Optimization (PSO) and Lingo in SMEIJI model. An example is provided in this study to illustrate how production run and defective rate have an effect on system costs. Finally, the results of our research could provide some managerial insights which support decision makers in real-world operations.

Platform-Intermediated Trade with Uncertain Quality

Platform-Intermediated Trade with Uncertain Quality

Platform-Intermediated Trade with Uncertain Quality

Author(s): Hermalin, BE | Abstract: Consider trade conducted via a platform, such as an online app store or a farmers’ market. The quality sellers choose for their products affects the surplus trade generates. Because the platform’s profit depends on that surplus, the platform can have an incentive to regulate quality. This is true even if quality is observable at time of purchase or if sellers can develop reputations concerning quality. It is also true if the platform charges sellers only; that is, even if the platform has no direct interest in buyers’ well-being.

Platform-Intermediated Trade with Uncertain Quality

Platform-Intermediated Trade with Uncertain Quality

Are the Newer Antidiabetic Agents Worth the Cost?

Type 2 Diabetes Mellitus (T2DM) is a multisystem metabolic disease that requires lifelong medical management. While the burden of T2DM to society can be measured in dollars and rupees, the cost of T2DM to the patient may be immeasurable, reflecting the daily challenges of this chronic disease and uncertain quality of life. Citizens of the 21st century are experiencing a pandemic of T2DM which has motivated development of an armamentarium of new antidiabetic drugs. The new antidiabetic medicines, classified by mechanism of action, include: (i) the glucagon like polypeptide (GLP-1) analogues exenatide and liraglutide; (ii) the renal sodium glucose transport-2 (SGLT-2) inhibitors canagliflozin and dafagliflozin; (iii) the dipeptidyl peptidase-4 (DPP-4) inhibitor sitagliptin; (iv) the amylin analogue pramlinitide; and (v) the insulin analogues: aspart, lispro, and glargine. The older, conventional antidiabetic medicines such as glibenclamide, glimepiride, metformin, pioglitazone, and the insulin preparations are, largely, much less expensive and therefore more affordable to the diabetic patient than the newer drugs. Furthermore, it is known that patient compliance with antidiabetic treatments, almost exclusively, depends on the direct cost to the patient [1]. This problem of compliance is magnified by the fact that antidiabetic treatments are lifelong and, hence, present the diabetic patient with substantial financial, behavioral and emotional challenges which must be overcome. Another challenge is that patients may not have health insurance, but even if they do, health insurance policies often do not cover drugs for outpatient use. Zhang et al., analysed the benefits and harms of antihyperglycaemic treatment regimens considering clinical effectiveness, quality of life, and cost. They found that older agents like sulfonylureas were associated with greater benefit in terms of both life-years, quality adjusted life years, and less expensive compared with newer glucose lowering agents like, sitagliptin and exenatide. Monthly medication cost (USD) of metformin 81.75, sulfonylurea 54.85, whereas newer medications like GLP-1 agonist 325.97, DPP-4 inhibitor 232.84 [2]. Limited knowledge of the longterm safety of the newer antidiabetic agents is another important issue. For example, it has been reported that, a 51-year-old woman with longstanding T2DM developed liraglutide induced acute pancreatitis. Her symptoms resolved after withdrawal of this GLP-1 analogue [3]. GLP-1 agonists are contraindicated in patients with histories of pancreatitis, glomerular filtration rate < 30 mL/min, or gastroparesis. Another report demonstrates a significant risk of subclinical pancreatic inflammation, pancreatic cancer, and neuroendocrine tumours in users of exenatide [4]. The DPP-4 inhibitors are commonly associated with nasopharyngitis, headache, and respiratory infections, but pancreatitis, pancreatic cancer, elevation of hepatic enzyme activity; skin reactions and severe joint pain are also reported in users of DPP-4 inhibitors [5]. The SGLT-2 inhibitors are known to cause urinary and genital tract infections, dehydration, and hyperkalaemia. As per a recent report of a 60-year-old man with T2DM treated with glimepiride, metformin, insulin, and canagliflozin developed hypercalcaemia due to intestinal and urinary calcium absorption possibly due to inhibition of SGLT by the canagliflozin [6]. These are but a few examples of why more research is needed to support the safe use of these novel antidiabetic agents. Apart from the financial challenges faced by diabetic patients there is substantial uncertainty about the safety of the newer antidiabetic drugs—newer is not necessarily better.

An Uncertain QFD Approach for the Strategic Management of Logistics Services

Due to customers’ growing concern about logistics performances related to products, logistics service increasingly contributes to the core competence of an enterprise or product, which calls an appropriate tool to develop effective strategic actions to improve logistics performances and gain customer satisfaction. Therefore, an uncertain quality function deployment (QFD) approach for selecting the most effective strategic actions in terms of efficiency to meet the customer requirements is developed in this paper, which integrates uncertainty theory into the traditional QFD methodology in order to rationally deal with imprecise information inherently involved in the QFD process. The framework and systematic procedures of the approach are presented in the context of logistics services. Specifically, the calculations for the prioritization of strategic actions are discussed in detail, in which uncertain variables are used to capture the linguistic judgements given by customers and experts. Applications of the proposed approach are presented as well for illustration.

Losigamone add-on therapy for partial epilepsy.

Epilepsy is a common neurologic disorder, affecting approximately 50 million people worldwide; nearly a third of these people are not well controlled by a single antiepileptic drug (AED) and usually require treatment with a combination of two or more AEDs. In recent years, many newer AEDs have been investigated as add-on therapy for partial epilepsy; losigamone is one of these drugs and is the focus of this systematic review. This is an update of a Cochrane review first published in 2012 (Cochrane Database of Systematic Reviews 2012, Issue 6). To investigate the efficacy and safety of losigamone when used as an add-on therapy for partial epilepsy. We searched the Cochrane Epilepsy Group Specialized Register (16 February 2015), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 16 February 2015) and MEDLINE (Ovid, 1946 to 16 February 2015). We searched trials registers and contacted themanufacturer of losigamone and authors of included studies for additional information. We did not impose any language restrictions. Randomized controlled, add-on trials comparing losigamone with placebo for partial epilepsy. Two review authors independently assessed trial quality and extracted data. The primary outcomes were 50% or greater reduction in seizure frequency and seizure freedom; the secondary outcomes were treatment withdrawal and adverse events. Results are presented as risk ratios (RRs) with 95% confidence intervals (CIs) or 99% CIs (for the individual listed adverse events to make an allowance for multiple testing). Two trials involving a total of 467 patients, aged over 18 years, were eligible for inclusion. Both trials assessed losigamone 1200 mg/day or 1500 mg/day as an add-on therapy for partial epilepsy. One trial was assessed as being of good methodological quality while the other was of uncertain quality. For the efficacy outcomes, results did show patients taking losigamone were significantly more likely to achieve a 50% or greater reduction in seizure frequency (RR 1.76; 95% CI 1.14 to 2.72), but associated with a significant increase of treatment withdrawal when compared with those taking placebo (RR 2.16; 95% CI 1.28 to 3.67). For the safety outcomes, results indicated the proportion of patients who experienced adverse events in the losigamone group was higher than the placebo group (RR 1.34; 95% CI 1.00 to 1.80), dizziness was the only adverse event significantly reported in relation to losigamone (RR 3.82; 99% CI 1.69 to 8.64). The proportion of patients achieving seizure freedom was not reported in either trial report. A subgroup analysis according to different doses of losigamone showed that a higher dose of losigamone (1500 mg/day) was associated with a greater reduction in seizure frequency than lower doses, but was also associated with more dropouts due to adverse events. The results of this review showed losigamone did reduce seizure frequency but was associated with more treatment withdrawals when used as an add-on therapy for people with partial epilepsy. However, trials included were of short-term duration and uncertain quality. Future well-designed randomized, double-blind, placebo-controlled trials with a longer-term duration are needed. No new studies have been found since the last version of this review.

The Role of Networks in International Trade with Uncertain Product Quality

Networks, primarily common language and colonial ties, are known to help foster trade. I propose that a channel though which common language acts to foster trade is through distinguishing the quality of a variety. When the quality of a variety has a higher level of uncertainty, sharing a common language helps to foster more trade for these varieties as it reduces uncertainty. Also using sharing a common language increases the likelihood of an exporter staying in the market.

Experimentally validated stochastic geometry description for textile composite reinforcements

The uncertain quality of composites, due to variability in the mechanical response, forces design engineers to employ high safety margins to ensure that the design requirements are met. Especially for textile composites, an improved assessment of the quality of any composite material is achieved by identification and simulation of the inherent uncertainty in the reinforcement geometry. This paper presents such a comprehensive multi-scale strategy to develop realistic stochastic replicas of a composite material, with emphasis on the identification step. First, the scatter in the tow reinforcement is characterised on the short-range (meso-scale) and long-range (macro-scale) from high-resolution images. Next, a probabilistic uncertainty quantification method is proposed to analyse the variability of each path parameter in terms of average trend, standard deviation and correlation information. This set of statistical information is essential to reproduce the random textile geometry in a numerical simulation approach. The multi-scale framework delivers representative models in the WiseTex format and is demonstrated for a carbon-epoxy 2/2 twill woven composite produced by resin transfer moulding.

Integrated crude selection and refinery optimization under uncertainty

Crude oil selection and procurement is the most important step in the refining process and impacts the profit margin of the refinery significantly. Due to uncertain quality of the crudes, conventional deterministic modeling and optimization methods are not suitable for refinery profitability enhancement. Therefore, a novel optimization scheme for crude oil procurement integrated with refinery operations in the face of uncertainties is presented. The decision process comprises two stages and is solved using a scenario‐based stochastic programming formulation. In Stage I, the optimal crude selections and purchase amounts are determined by maximizing the expected profit across all scenarios. In Stage II, the uncertainties are realized and optimal operations for the refinery are determined according to this realization. The resulting large‐scale mixed‐integer nonlinear programming formulation incorporates integer variables for crude selection and continuous variables for refinery operations, as well as bilinear terms for pooling processes. Nonconvex generalized Benders decomposition is used to solve this problem to obtain an global optimum efficiently. © 2015 American Institute of Chemical Engineers AIChE J, 62: 1038–1053, 2016

Дискретная задача оптимального управления с неопределённым критериям качества

Дискретная задача оптимального управления с неопределённым критериям качества