2,032 research outputs found

    Common Biases In Business Research

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    In research, bias occurs when an error is introduced into sampling or testing which results in selecting or encouraging one outcome, conclusion, or answer over others. Bias can happen at any phase of research, including study design, methodology selection, data collection, and stating conclusions [1]. Given the significant threats of these biases on the reliability and validity of research conclusions, understanding different types of biases, their consequences, and treatment methods is the corner stone in avoiding such biases and an important step in critically evaluating research. This chapter discusses biases that are common in quantitative research, biases associated with quantitative research and biases that usually occur in quantitative research using qualitative data. It will focus on introducing business researchers to their definitions and sources. The chapter also suggests methods to uncover those biases and provides remedies and ways to deal with such biases

    Inhibitory properties of ibuprofen and its amide analogues towards the hydrolysis and cyclooxygenation of the endocannabinoid anandamide

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    A dual-action cyclooxygenase (COX)–fatty acid amide hydrolase (FAAH) inhibitor may have therapeutic usefulness as an analgesic, but a key issue is finding the right balance of inhibitory effects. This can be done by the design of compounds exhibiting different FAAH/COX-inhibitory potencies. In the present study, eight ibuprofen analogues were investigated. Ibuprofen (1), 2-(4-Isobutylphenyl)-N-(2-(3-methylpyridin-2-ylamino)-2-oxoethyl)propanamide (9) and N-(3-methylpyridin-2-yl)-2-(4′-isobutylphenyl)propionamide (2) inhibited FAAH with IC50 values of 134, 3.6 and 0.52 µM respectively. The corresponding values for COX-1 were ~29, ~50 and ~60 µM, respectively. Using arachidonic acid as substrate, the compounds were weak inhibitors of COX-2. However, when anandamide was used as COX-2 substrate, potency increased, with approximate IC50 values of ~6, ~10 and ~19 µM, respectively. Compound 2 was confirmed to be active in vivo in a murine model of visceral nociception, but the effects of the compound were not blocked by CB receptor antagonists. Read More: http://informahealthcare.com/doi/abs/10.3109/14756366.2011.64330

    Factors affecting continuation of clean intermittent catheterisation in people with multiple sclerosis: results of the COSMOS mixed-methods study

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    Background:  Clean intermittent catheterisation (CIC) is often recommended for people with multiple sclerosis (MS).  Objective:  To determine the variables that affect continuation or discontinuation of the use of CIC.  Methods:  A three-part mixed-method study (prospective longitudinal cohort (n = 56), longitudinal qualitative interviews (n = 20) and retrospective survey (n = 456)) was undertaken, which identified the variables that influenced CIC continuation/discontinuation. The potential explanatory variables investigated in each study were the individual’s age, gender, social circumstances, number of urinary tract infections, bladder symptoms, presence of co-morbidity, stage of multiple sclerosis and years since diagnosis, as well as CIC teaching method and intensity.  Results:  For some people with MS the prospect of undertaking CIC is difficult and may take a period of time to accept before beginning the process of using CIC. Ongoing support from clinicians, support at home and a perceived improvement in symptoms such as nocturia were positive predictors of continuation. In many cases, the development of a urinary tract infection during the early stages of CIC use had a significant detrimental impact on continuation.  Conclusion:  Procedures for reducing the incidence of urinary tract infection during the learning period (i.e. when being taught and becoming competent) should be considered, as well as the development of a tool to aid identification of a person’s readiness to try CIC

    Decreased copper in alzheimer's disease brain is predominantly in the soluble extractable fraction

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    Alzheimer's disease (AD) is the leading cause of dementia and represents a significant burden on the global economy and society. The role of transition metals, in particular copper (Cu), in AD has become of significant interest due to the dyshomeostasis of these essential elements, which can impart profound effects on cell viability and neuronal function. We tested the hypothesis that there is a systemic perturbation in Cu compartmentalization in AD, within the brain as well as in the periphery, specifically within erythrocytes. Our results showed that the previously reported decrease in Cu within the human frontal cortex was confined to the soluble (P<0.05) and total homogenate (P<0.05) fractions. No differences were observed in Cu concentration in erythrocytes. Our data indicate that there is a brain specific alteration in Cu levels in AD localized to the soluble extracted material, which is not reflected in erythrocytes. Further studies using metalloproteomics approaches will be able to elucidate the metabolic mechanism(s) that results in the decreased brain Cu levels during the progression of AD. © 2013 Alan Rembach et al

    Discovery of mating in the major African livestock pathogen Trypanosoma congolense

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    The protozoan parasite, Trypanosoma congolense, is one of the most economically important pathogens of livestock in Africa and, through its impact on cattle health and productivity, has a significant effect on human health and well being. Despite the importance of this parasite our knowledge of some of the fundamental biological processes is limited. For example, it is unknown whether mating takes place. In this paper we have taken a population genetics based approach to address this question. The availability of genome sequence of the parasite allowed us to identify polymorphic microsatellite markers, which were used to genotype T. congolense isolates from livestock in a discrete geographical area of The Gambia. The data showed a high level of diversity with a large number of distinct genotypes, but a deficit in heterozygotes. Further analysis identified cryptic genetic subdivision into four sub-populations. In one of these, parasite genotypic diversity could only be explained by the occurrence of frequent mating in T. congolense. These data are completely inconsistent with previous suggestions that the parasite expands asexually in the absence of mating. The discovery of mating in this species of trypanosome has significant consequences for the spread of critical traits, such as drug resistance, as well as for fundamental aspects of the biology and epidemiology of this neglected but economically important pathogen

    Managing uncertainty in data-derived densities to accelerate density functional theory

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    Faithful representations of atomic environments and general models for regression can be harnessed to learn electron densities that are close to the ground state. One of the applications of data-derived electron densities is to orbital-free density functional theory. However, extrapolations of densities learned from a training set to dissimilar structures could result in inaccurate results, which would limit the applicability of the method. Here, we show that a non-Bayesian approach can produce estimates of uncertainty which can successfully distinguish accurate from inaccurate predictions of electron density. We apply our approach to density functional theory where we initialise calculations with data-derived densities only when we are confident about their quality. This results in a guaranteed acceleration to self-consistency for configurations that are similar to those seen during training and could be useful for sampling based methods, where previous ground state densities cannot be used to initialise subsequent calculations

    Plasmodium knowlesi Genome Sequences from Clinical Isolates Reveal Extensive Genomic Dimorphism.

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    Plasmodium knowlesi is a newly described zoonosis that causes malaria in the human population that can be severe and fatal. The study of P. knowlesi parasites from human clinical isolates is relatively new and, in order to obtain maximum information from patient sample collections, we explored the possibility of generating P. knowlesi genome sequences from archived clinical isolates. Our patient sample collection consisted of frozen whole blood samples that contained excessive human DNA contamination and, in that form, were not suitable for parasite genome sequencing. We developed a method to reduce the amount of human DNA in the thawed blood samples in preparation for high throughput parasite genome sequencing using Illumina HiSeq and MiSeq sequencing platforms. Seven of fifteen samples processed had sufficiently pure P. knowlesi DNA for whole genome sequencing. The reads were mapped to the P. knowlesi H strain reference genome and an average mapping of 90% was obtained. Genes with low coverage were removed leaving 4623 genes for subsequent analyses. Previously we identified a DNA sequence dimorphism on a small fragment of the P. knowlesi normocyte binding protein xa gene on chromosome 14. We used the genome data to assemble full-length Pknbpxa sequences and discovered that the dimorphism extended along the gene. An in-house algorithm was developed to detect SNP sites co-associating with the dimorphism. More than half of the P. knowlesi genome was dimorphic, involving genes on all chromosomes and suggesting that two distinct types of P. knowlesi infect the human population in Sarawak, Malaysian Borneo. We use P. knowlesi clinical samples to demonstrate that Plasmodium DNA from archived patient samples can produce high quality genome data. We show that analyses, of even small numbers of difficult clinical malaria isolates, can generate comprehensive genomic information that will improve our understanding of malaria parasite diversity and pathobiology

    Fowler's syndrome: a primary disorder of urethral sphincter relaxation

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    Key content: Urinary retention is a relatively uncommon presentation in young women. Women with Fowler's syndrome are often found to have an abnormally elevated urethral pressure profile, increased urethral sphincter volume and characteristically abnormal electromyography of the urethral sphincter. The only treatment that has been found to restore voiding in women with Fowler's syndrome is sacral neuromodulation. Sphincter injections of botulinum toxin are a possible outpatient‐based alternative. / Learning objectives: To review the typical symptoms and signs associated with Fowler's syndrome. To share the current understanding about why this condition may occur. To understand how to evaluate and treat a woman with suspected Fowler's syndrome. / Ethical issues: Fowler's syndrome should be considered in women presenting with urinary retention where the cause for retention is uncertain

    How consistent are the transcriptome changes associated with cold acclimation in two species of the Drosophila virilis group?

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    This work was financially support by a Marie Curie Initial Training Network grant, “Understanding the evolutionary origin of biological diversity” (ITN-2008–213780 SPECIATION), grants from the Academy of Finland to A.H. (project 132619) and M.K. (projects 268214 and 272927), a grant from NERC, UK to M.G.R. (grant NE/J020818/1), and NERC, UK PhD studentship to D.J.P. (NE/I528634/1).For many organisms the ability to cold acclimate with the onset of seasonal cold has major implications for their fitness. In insects, where this ability is widespread, the physiological changes associated with increased cold tolerance have been well studied. Despite this, little work has been done to trace changes in gene expression during cold acclimation that lead to an increase in cold tolerance. We used an RNA-Seq approach to investigate this in two species of the Drosophila virilis group. We found that the majority of genes that are differentially expressed during cold acclimation differ between the two species. Despite this, the biological processes associated with the differentially expressed genes were broadly similar in the two species. These included: metabolism, cell membrane composition, and circadian rhythms, which are largely consistent with previous work on cold acclimation/cold tolerance. In addition, we also found evidence of the involvement of the rhodopsin pathway in cold acclimation, a pathway that has been recently linked to thermotaxis. Interestingly, we found no evidence of differential expression of stress genes implying that long-term cold acclimation and short-term stress response may have a different physiological basis.PostprintPeer reviewe
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