1,624 research outputs found
Time Use and Educational Attainment: A Study of Undergraduate Students
This research examines the effects of students' time use in academically related activities and paid employment on their educational attainment. A theoretical model containing fourteen background, social psychological, time use, and educational attainment variables was formulated. The data were obtained from questionnaires administered to 308 undergraduate students in the Faculty of Education at a Western Canadian University. A stratified random cluster sampling procedure was used to select classes of students. Structural equation modelling is used to test the relationships among the variables. Results indicate that when other variables are taken into account, the time students spend in academically related activities and paid employment has little effect on their educational achievement and their educational expectations.Cette recherche examine les effets de la répartition du temps d'étude et du temps alloué à un emploi sur le succès académique des étudiants. Un modèle théorique comportant quatorze variables de type général, socio-psychologique, d'utilisation du temps, et portant sur les résultats de l'expérience éducative, a été développé. Les données ont été obtenues d'une enquête effectuée auprès de 308 étudiants non diplômés de la faculté d'éducation d'une université canadienne. Une méthode d'échantillonnage stratifié par groupe a été utilisée pour sélectionner les groupes-cibles d'étudiants. Une modélisation par équation structurale a été effectuée pour analyser les résultats. Ils indiquent, qu'une fois l'effet des autres variables pris en compte, le temps dédié aux activités académiques et à un emploi rémunéré a peu d'impact sur le succès académique des étudiants et sur leurs attentes en matière de formation
SNAPPI-DB: a database and API of Structures, iNterfaces and Alignments for Protein–Protein Interactions
SNAPPI-DB, a high performance database of Structures, iNterfaces and Alignments of Protein–Protein Interactions, and its associated Java Application Programming Interface (API) is described. SNAPPI-DB contains structural data, down to the level of atom co-ordinates, for each structure in the Protein Data Bank (PDB) together with associated data including SCOP, CATH, Pfam, SWISSPROT, InterPro, GO terms, Protein Quaternary Structures (PQS) and secondary structure information. Domain–domain interactions are stored for multiple domain definitions and are classified by their Superfamily/Family pair and interaction interface. Each set of classified domain–domain interactions has an associated multiple structure alignment for each partner. The API facilitates data access via PDB entries, domains and domain–domain interactions. Rapid development, fast database access and the ability to perform advanced queries without the requirement for complex SQL statements are provided via an object oriented database and the Java Data Objects (JDO) API. SNAPPI-DB contains many features which are not available in other databases of structural protein–protein interactions. It has been applied in three studies on the properties of protein–protein interactions and is currently being employed to train a protein–protein interaction predictor and a functional residue predictor. The database, API and manual are available for download at:
Uncovering the natural variability of araucariacean exudates from ex situ and in situ tree populations in New Caledonia using FTIR spectroscopy
Background Understanding the natural variability of plant resins is crucial for evaluating the chemical information stored in ambers that may support inferring palaeoenvironmental conditions. However, even among extant resin-producing plants, the variation of resinous exudates within and between tree genera and species is still poorly understood. Methods We analysed plant exudates from across the Araucariaceae in New Caledonia using Fourier-transform infrared spectroscopy in attenuated total reflection mode (FTIR-ATR). Both, wild (in situ) and arboretum grown (ex situ) populations were used to uncover the effects of intergeneric, inter- and intraspecific variation of the araucariacean plants on the resin chemistry. Results We show that even resins from the same species in the same habitat do have natural (intraspecific) chemical variation. Some of the variation can result from the degree of resin polymerisation, but this is not the only source of variation. Wild sourced resins have greater natural intraspecific chemical variation than the arboretum sourced ones. Interspecific and intergeneric differences were not easy to distinguish in the resins sampled. This has strong implications for the evaluation of the chemical information from worldwide ambers: multiple samples should be analysed to give a more accurate picture of the natural chemical variation present and how this may or may not overlap with the chemistries of other resin types. Additionally we discovered that the Araucariacean species can produce up to three distinct types of exudate (gum, resin, and gum resin). This is the first time that gum resins have been identified and characterized with FTIR-ATR. We also provide a guide on how to distinguish the exudate types when using FTIR-ATR.Peer reviewe
Autoimmune hyperphosphatemic tumoral calcinosis in a patient with FGF23 autoantibodies
Hyperphosphatemic familial tumoral calcinosis (HFTC)/hyperostosis-hyperphosphatemia syndrome (HHS) is an autosomal recessive disorder of ectopic calcification due to deficiency of or resistance to intact fibroblast growth factor 23 (iFGF23). Inactivating mutations in FGF23, N-acetylgalactosaminyltransferase 3 (GALNT3), or KLOTHO (KL) have been reported as causing HFTC/HHS. We present what we believe is the first identified case of autoimmune hyperphosphatemic tumoral calcinosis in an 8-year-old boy. In addition to the classical clinical and biochemical features of hyperphosphatemic tumoral calcinosis, the patient exhibited markedly elevated intact and C-terminal FGF23 levels, suggestive of FGF23 resistance. However, no mutations in FGF23, KL, or FGF receptor 1 (FGFR1) were identified. He subsequently developed type 1 diabetes mellitus, which raised the possibility of an autoimmune cause for hyperphosphatemic tumoral calcinosis. Luciferase immunoprecipitation systems revealed markedly elevated FGF23 autoantibodies without detectable FGFR1 or Klotho autoantibodies. Using an in vitro FGF23 functional assay, we found that the FGF23 autoantibodies in the patient's plasma blocked downstream signaling via the MAPK/ERK signaling pathway in a dose-dependent manner. Thus, this report describes the first case, to our knowledge, of autoimmune hyperphosphatemic tumoral calcinosis with pathogenic autoantibodies targeting FGF23. Identification of this pathophysiology extends the etiologic spectrum of hyperphosphatemic tumoral calcinosis and suggests that immunomodulatory therapy may be an effective treatment
Cretaceous gnetalean yields first preserved plant gum
Some liquid plant exudates (e.g. resin) can be found preserved in the fossil record. However, due to their high solubility, gums have been assumed to dissolve before fossilisation. The visual appearance of gums (water-soluble polysaccharides) is so similar to other plant exudates, particularly resin, that chemical testing is essential to differentiate them. Remarkably, Welwitschiophyllum leaves from Early Cretaceous, Brazil provide the first chemical confirmation of a preserved gum. This is despite the leaves being exposed to water twice during formation and subsequent weathering of the Crato Formation. The Welwitschiophyllum plant shares the presence of gum ducts inside leaves with its presumed extant relative the gnetalean Welwitschia. This fossil gum presents a chemical signature remarkably similar to the gum in extant Welwitschia and is distinct from those of fossil resins. We show for the first time that a water-soluble plant exudate has been preserved in the fossil record, potentially allowing us to recognise further biomolecules thought to be lost during the fossilisation process
Reinvestigating the fossil leaf <i>Welwitschiophyllum brasiliense</i> Dilcher et al. (2005), from the Lower Cretaceous Crato Formation of Brazil
Polyploidy breaks speciation barriers in Australian burrowing frogs Neobatrachus
Polyploidy has played an important role in evolution across the tree of life but it is still unclear how polyploid lineages may persist after their initial formation. While both common and well-studied in plants, polyploidy is rare in animals and generally less understood. The Australian burrowing frog genus Neobatrachus is comprised of six diploid and three polyploid species and offers a powerful animal polyploid model system. We generated exome-capture sequence data from 87 individuals representing all nine species of Neobatrachus to investigate species-level relationships, the origin and inheritance mode of polyploid species, and the population genomic effects of polyploidy on genus-wide demography. We describe rapid speciation of diploid Neobatrachus species and show that the three independently originated polyploid species have tetrasomic or mixed inheritance. We document higher genetic diversity in tetraploids, resulting from widespread gene flow between the tetraploids, asymmetric inter-ploidy gene flow directed from sympatric diploids to tetraploids, and isolation of diploid species from each other. We also constructed models of ecologically suitable areas for each species to investigate the impact of climate on differing ploidy levels. These models suggest substantial change in suitable areas compared to past climate, which correspond to population genomic estimates of demographic histories. We propose that Neobatrachus diploids may be suffering the early genomic impacts of climate-induced habitat loss, while tetraploids appear to be avoiding this fate, possibly due to widespread gene flow. Finally, we demonstrate that Neobatrachus is an attractive model to study the effects of ploidy on the evolution of adaptation in animals
Homeopathy for treatment of irritable bowel syndrome
BACKGROUND: Irritable bowel syndrome (IBS) is a common, chronic disorder that leads to decreased health-related quality of life and work productivity. A previous version of this review was not able to draw firm conclusions about the effectiveness of homeopathic treatment for IBS and recommended that further high quality RCTs were conducted to explore the clinical and cost effectiveness of homeopathic treatment for IBS. Two types of homeopathic treatment were evaluated in this systematic review: 1. Clinical homeopathy where a specific remedy is prescribed for a specific condition; 2. Individualised homeopathic treatment, where a homeopathic remedy based on a person's individual symptoms is prescribed after a detailed consultation. OBJECTIVES: To assess the effectiveness and safety of homeopathic treatment for IBS. SEARCH METHODS: For this update we searched MEDLINE, CENTRAL, Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Allied and Complementary Medicine Database (AMED), the Cochrane IBD Group Specialised Register and trials registers from inception to 31 August 2018. SELECTION CRITERIA: Randomised controlled trials (RCTs), cohort and case-control studies that compared homeopathic treatment with placebo, other control treatments, or usual care, in adults with IBS were considered for inclusion. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the risk of bias and extracted data. The primary outcome was global improvement in IBS as measured by an IBS symptom severity score. Secondary outcomes included quality of life, abdominal pain, stool frequency, stool consistency, and adverse events. The overall certainty of the evidence supporting the primary and secondary outcomes was assessed using the GRADE criteria. We used the Cochrane risk of bias tool to assess risk of bias. We calculated the mean difference (MD) and 95% confidence interval (CI) for continuous outcomes and the risk ratio (RR) and 95% CI for dichotomous outcomes. MAIN RESULTS: Four RCTs (307 participants) were included. Two studies compared clinical homeopathy (homeopathic remedy, asafoetida or asafoetida plus nux vomica) to placebo for IBS with constipation (IBS-C). One study compared individualised homeopathic treatment (consultation plus remedy) to usual care for the treatment of IBS in female patients. One study was a three armed RCT comparing individualised homeopathic treatment to supportive listening or usual care. The risk of bias in three studies (the two studies assessing clinical homeopathy and the study comparing individualised homeopathic treatment to usual care) was unclear on most criteria and high for selective reporting in one of the clinical homeopathy studies. The three armed study comparing individualised homeopathic treatment to usual care and supportive listening was at low risk of bias in four of the domains and high risk of bias in two (performance bias and detection bias).A meta-analysis of the studies assessing clinical homeopathy, (171 participants with IBS-C) was conducted. At short-term follow-up of two weeks, global improvement in symptoms was experienced by 73% (46/63) of asafoetida participants compared to 45% (30/66) of placebo participants (RR 1.61, 95% CI 1.18 to 2.18; 2 studies, very low certainty evidence). In the other clinical homeopathy study at two weeks, 68% (13/19) of those in the asafoetida plus nux vomica arm and 52% (12/23) of those in the placebo arm experienced a global improvement in symptoms (RR 1.31, 95% CI 0.80 to 2.15; very low certainty evidence). In the study comparing individualised homeopathic treatment to usual care (N = 20), the mean global improvement score (feeling unwell) at 12 weeks was 1.44 + 4.55 (n = 9) in the individualised homeopathic treatment arm compared to 1.41 + 1.97 (n=11) in the usual care arm (MD 0.03; 95% CI -3.16 to 3.22; very low certainty evidence).In the study comparing individualised homeopathic treatment to usual care, the mean IBS symptom severity score at 6 months was 210.44 + 112.4 (n = 16) in the individualised homeopathic treatment arm compared to 237.3 + 110.22 (n = 60) in the usual care arm (MD -26.86, 95% CI -88.59 to 34.87; low certainty evidence). The mean quality of life score (EQ-5D) at 6 months in homeopathy participants was 69.07 (SD 17.35) compared to 63.41 (SD 23.31) in usual care participants (MD 5.66, 95% CI -4.69 to 16.01; low certainty evidence).For In the study comparing individualised homeopathic treatment to supportive listening, the mean IBS symptom severity score at 6 months was 210.44 + 112.4 (n = 16) in the individualised homeopathic treatment arm compared to 262 + 120.72 (n = 18) in the supportive listening arm (MD -51.56, 95% CI -129.94 to 26.82; very low certainty evidence). The mean quality of life score at 6 months in homeopathy participants was 69.07 (SD 17.35) compared to 63.09 (SD 24.38) in supportive listening participants (MD 5.98, 95% CI -8.13 to 20.09; very low certainty evidence).None of the included studies reported on abdominal pain, stool frequency, stool consistency, or adverse events. AUTHORS' CONCLUSIONS: The results for the outcomes assessed in this review are uncertain. Thus no firm conclusions regarding the effectiveness and safety of homeopathy for the treatment of IBS can be drawn. Further high quality, adequately powered RCTs are required to assess the efficacy and safety of clinical and individualised homeopathy for IBS compared to placebo or usual care
Enhanced Cellular Immunity in Shrimp (Litopenaeus vannamei) after ‘Vaccination’
It has long been viewed that invertebrates rely exclusively upon a wide variety of innate mechanisms for protection from disease and parasite invasion and lack any specific acquired immune mechanisms comparable to those of vertebrates. Recent findings, however, suggest certain invertebrates may be able to mount some form of specific immunity, termed ‘specific immune priming’, although the mechanism of this is not fully understood (see Textbox S1). In our initial experiments, either formalin-inactivated Vibrio harveyi or sterile saline were injected into the main body cavity (haemocoel) of juvenile shrimp (Litopenaeus vannamei). Haemocytes (blood cells) from V. harveyi-injected shrimp were collected 7 days later and incubated with a 1∶1 mix of V. harveyi and an unrelated Gram positive bacterium, Bacillus subtilis. Haemocytes from ‘vaccinated’ shrimp showed elevated levels of phagocytosis of V. harveyi, but not B. subtilis, compared with those from saline-injected (non-immunised) animals. The increased phagocytic activity was characterised by a significant increase in the percentage of phagocytic cells. When shrimp were injected with B. subtilis rather than vibrio, there was no significant increase in the phagocytic activity of haemocytes from these animals in comparison to the non-immunised (saline injected) controls. Whole haemolymph (blood) from either ‘immunised’ or non-immunised’ shrimp was shown to display innate humoral antibacterial activity against V. harveyi that was absent against B. subtilis. However, there was no difference in the potency of antibacterial activity between V. harveyi-injected shrimp and control (saline injected) animals showing that ‘vaccination’ has no effect on this component of the shrimp's immune system. These results imply that the cellular immune system of shrimp, particularly phagocytosis, is capable of a degree of specificity and shows the phenomenon of ‘immune priming’ reported by other workers. However, in agreement with other studies, this phenomenon is not universal to all potential pathogens
- …