1,635 research outputs found

    Attention, predictive learning, and the inverse base-rate effect: Evidence from event-related potentials

    Get PDF
    We report the first electrophysiological investigation of the inverse base-rate effect (IBRE), a robust non-rational bias in predictive learning. In the IBRE, participants learn that one pair of symptoms (AB) predicts a frequently occurring disease, whilst an overlapping pair of symptoms (AC) predicts a rarely occurring disease. Participants subsequently infer that BC predicts the rare disease, a non-rational decision made in opposition to the underlying base rates of the two diseases. Error-driven attention theories of learning state that the IBRE occurs because C attracts more attention than B. On the basis of this account we predicted and observed the occurrence of brain potentials associated with visual attention: a posterior Selection Negativity, and a concurrent anterior Selection Positivity, for C vs. B in a post-training test phase. Error-driven attention theories further predict no Selection Negativity, Selection Positivity or IBRE, for control symptoms matched on frequency to B and C, but for which there was no shared symptom (A) during training. These predictions were also confirmed, and this confirmation discounts alternative explanations of the IBRE based on the relative novelty of B and C. Further, we observed higher response accuracy for B alone than for C alone; this dissociation of response accuracy (B>C) from attentional allocation (C>B) discounts the possibility that the observed attentional difference was caused by the difference in response accuracy

    PKB/Akt-Dependent Regulation of Cell Motility

    Get PDF
    The prosurvival activity of phosphoinositide 3 kinase (PI3K)/Akt (also known as protein kinase B, PKB) pathway has been investigated in great detail in human physiology and disease. Accumulating evidence is emerging that this signaling axis also actively engages with the migratory process in motile cells, including metastatic cancer cells. Interference with the role of PI3K/Akt-mediated cell motility impairs cellular development and attenuates malignant progression of cancer metastasis. Because metastasis is responsible for 90% of mortality in cancer patients, the acceleration of cancer cell spreading observed in association with hyperactivation of the PI3K pathway, triggered for example by chemotherapy/radiotherapy in the clinic, has heightened awareness of the conflict between "good drugs” and unfavorable effects. Here, we discuss recent studies on PI3K/Akt-regulated cell motility in both physiological and pathological settings, with the aim of a better understanding of how activities of the PI3K/Akt axis initiate and transmit "migratory signals” that stimulate cell movement. We focus in particular on its direct influence on cell migration and invasion, epithelial-mesenchymal transition, and cancer metastasi

    Perioperative factor concentrate therapy

    Get PDF
    Transfusion of allogeneic plasma has been a life-saving measure for decades in patients with severe trauma or suffering from major surgical blood loss. The safety of allogeneic blood components has improved in terms of pathogen transmission, but haemostatic efficacy of plasma is hindered by the large volume and time required for thawing and infusion. Several plasma-derived and recombinant factor concentrates are clinically available and indicated for targeted replacement of missing coagulation elements in hereditary disorders of thrombosis and haemostasis. When used appropriately, factor concentrate therapy can rapidly restore deficient factor(s) without causing volume overload. The haemostatic defect in perioperative patients is often multifactorial, and therefore careful clinical judgement and timely coagulation testing must be exercised before the administration of factor concentrates. In this review, the rationale for including factor concentrates in perioperative haemostatic management will be discussed in conjunction with the limitations of plasma transfusio

    Glycaemic control in the perioperative period

    Get PDF
    The prevalence of type 2 diabetes mellitus and the potential for perioperative dysglycaemia (hyperglycaemia, hypoglycaemia, stress-induced hyperglycaemia, or glucose variability) continue to increase dramatically. The majority of investigations on perioperative glycaemic control focused on critically ill patients and concentrated on goals of therapy, level of intensity of insulin infusion, feeding regimes, concerns over hypoglycaemia, and promulgation of recent guidelines calling for less strict glucose control. Areas of perioperative glycaemic control that deserve further investigation include preoperative identification of patients with undiagnosed type 2 diabetes and other forms of dysglycaemia, determination of appropriate intraoperative glucose goals, and establishment of the impact and natural history of perioperative abnormalities in glucose homeostasis. In the heterogeneous adult perioperative population, it is unlikely that one standard of perioperative glycaemic control is appropriate for all patients. This review presents recent evidence and expert guidance to aid preoperative assessment, intraoperative management, and postoperative care of the dysglycaemic adult patien

    Fungal genomics in respiratory medicine: what, how and when?

    Get PDF
    Respiratory infections caused by fungal pathogens present a growing global healthconcern and are a major cause of death in immunocompromised patients. Worryingly,coronavirus disease-19 (COVID-19) resulting in acute respiratory distress syndrome,has been shown to predispose some patients to fungal co-infection and secondarypulmonary aspergillosis. Aspergillosis is most commonly caused by the fungalpathogen Aspergillus fumigatus and primarily treated using the triazole drug group,however in recent years, this fungus has been rapidly gaining resistance against theseantifungals. This is of serious clinical concern as multi-azole resistant forms ofaspergillosis have a higher risk of mortality when compared against azole-susceptibleinfections. With the increasing numbers of COVID-19 and other classes ofimmunocompromised patients, early diagnosis of fungal infections is critical to ensuringpatient survival. However, time-limited diagnosis is difficult to achieve with currentculture-based methods. Advances within fungal genomics have enabled moleculardiagnostic methods to become a fast, reproducible, and cost-effective alternative fordiagnosis of respiratory fungal pathogens and detection of antifungal resistance. Herewe describe what techniques are currently available within molecular diagnostics, howthey work and when they have been used

    PI3K/AKT, MAPK and AMPK signalling: protein kinases in glucose homeostasis

    Get PDF
    New therapeutic approaches to counter the increasing prevalence of obesity and type 2 diabetes mellitus are in high demand. Deregulation of the phosphoinositide-3-kinase (PI3K)/v-akt murine thymoma viral oncogene homologue (AKT), mitogen-activated protein kinase (MAPK) and AMP-activated protein kinase (AMPK) pathways, which are essential for glucose homeostasis, often results in obesity and diabetes. Thus, these pathways should be attractive therapeutic targets. However, with the exception of metformin, which is considered to function mainly by activating AMPK, no treatment for the metabolic syndrome based on targeting protein kinases has yet been developed. By contrast, therapies based on the inhibition of the PI3K/AKT and MAPK pathways are already successful in the treatment of diverse cancer types and inflammatory diseases. This contradiction prompted us to review the signal transduction mechanisms of PI3K/AKT, MAPK and AMPK and their roles in glucose homeostasis, and we also discuss current clinical implication

    Crib Biting and Equine Gastric Ulceration Syndrome: do horses that display oral stereotypies have altered gastric anatomy and physiology?

    Get PDF
    Equine Gastric Ulceration Syndrome (EGUS) and Crib biting are two separate conditions suffered by horses. Previous research has hypothesised causal relationships between these two conditions, whereby the behavior is driven by a requirement to stimulate saliva production to buffer gastric juice. However to date there is limited empirical evidence to support this notion. To identify if the anatomy and physiology of the equid stomach differed in crib biting (CB) horses and non-crib biting controls (N-CB) a two part experiment was conducted using cadaver stomachs. Twenty four stomachs (n=12) CB and (n=12) N-CB were collected from an abattoir. Duplicate 1.5 cm squared sections were taken from the fundic and pyloric mucosa for histology and H&E staining to identify gastrin (G) producing cells. Slides were scored using an adapted four point scale. A further 18 stomachs, (n=9) CB and (n=9) N-CB were collected to test the pH of the mucosa and digesta from the fundic and pyloric regions. G cell concentrations were analysed by Mann Whitney U-46 test. Stomach content pH was analysed by one-way ANOVA and L.S.D post hoc. Relationships between digesta and mucosal pH were evaluated by correlation. In both parts of the study there was no difference between the G-cell concentration (P>0.05) and pH (P>0.05) between CB and N-CB horses. There was a positive correlation between digesta and the mucosal surface of pyloric region in CB horses (R2 0.66, P<0.001), but not in N-CB horses. These findings suggest, from cadavers, that CB and N-CB stomachs are not anatomically nor physiologically different. It is plausible that there is no direct inherent link between CB and EGUS rather that both conditions are linked to environmental and physiological stress

    Obtaining Gold: A Heuristic Inquiry on Successful Non-Traditional Black Male Students at a Midwestern Predominantly White Institution

    Get PDF
    Title from PDF of title page viewed June 22, 2021Dissertation advisor: Tiffani Riggers-PiehlVitaIncludes bibliographical references (pages 130-142)Thesis (Ed.D.)--School of Education. University of Missouri--Kansas City, 2021The purpose of this qualitative, heuristic study was to explore the successful experiences of nontraditional Black male students at predominantly white institutions (PWIs) in the Midwest. With an astounding rate of growth of the nontraditional student populations in higher education, this study was conducted to contribute to the literature on nontraditional students; challenge deficit views on Black male education, and highlight the perspectives of successful nontraditional Black males in a postsecondary setting. As of this writing, extensive research focuses on the barriers to success such as racism, financial hardship, and lack of role models that hinder their success at colleges and universities, with little centering on the innate skills and abilities that lead to Black male success. This study was designed to promote the voices of successful Black male students and understand their perceptions of influences that contribute to their college success with a focus on students that identify as nontraditional. The research questions were: (1) How do nontraditional Black male students define success? (2) What are the college experiences of successful nontraditional Black male students at Mid Western University? and (3) To what internal and external factors do nontraditional Black male students attribute their college success? Fourteen Black male students who identified as nontraditional were interviewed, and the findings were utilized to explore the research questions for this qualitative study. The primary method of data analysis were the six basic phases in the heuristic process of phenomenological analysis: (a) initial engagement, (b) immersion, (c) incubation, (d) illumination, (e) explication, and (f) creative synthesis (Moustakas, 1990). Students provided varying definitions of success: (1) social integration and (2) independent thinking and financial independence. In defining what contributed to their success, two themes were discovered: (1) the value and beliefs of life and (2) support and belonging. Students suggested that they had intrinsic motivations and external motivators helping them succeed in terms of their values and beliefs. Additionally, students identified multiple sources of support and belonging, including acceptance, peer interactions, family influence, and building connections and relationships. The study findings are insightful as to how these nontraditional Black male students perceived their college success. Implications for this study include changing the overall negative narrative of Black male students and especially those who identify as nontraditional, by giving them the needed voice of their perceptions which aided their success. As PWIs look at increasing enrollment, retention, and graduation rates of this population, there is a need to expand the identified approaches, programs, and supports that participants attribute to their success. Future research direction includes: (1) an exploration of experiences of the nontraditional Black male student, their journey from elementary education to college; (2) a narrative study on faculty and staff perspectives on nontraditional Black male students; (3) a longitudinal inquiry to provide a national perspective on the success of nontraditional Black male students who attended five years after graduation; (4) increased research that uses asset-based and anti-deficit approaches to illuminate nontraditional Black male students’ voices. Keywords: Black males, nontraditional, success, anti-deficit, higher educationIntroduction -- Literature review -- Methodology -- Findings -- Conclusion and recommendations -- Appendix A. Consent to participate in research study -- Appendix B. IRB approval -- Appendix C. Letter to prospective participants -- Appendix D. Interview protocol -- Appendix E. Consent to audiotaping and transcription -- Appendix F. Thoughts and reflection

    The influence of long- and short-term volcanic strain on aquifer pressure:a case study from Soufrière Hills Volcano, Montserrat (W.I.)

    Get PDF
    Aquifers are poroelastic bodies that respond to strain by changes in pore pressure. Crustal deformation due to volcanic processes induces pore pressure variations that are mirrored in well water levels. Here, we investigate water level changes in the Belham valley on Montserrat over the course of two years (2004-2006). Using finite element analysis, we simulate crustal deformation due to different volcanic strain sources and the dynamic poroelastic aquifer response. While some additional hydrological drivers cannot be excluded, we suggest that a poroelastic strain response of the aquifer system in the Belham valley is a possible explanation for the observed water level changes. According to our simulations, the shallow Belham aquifer responds to a steadily increasing sediment load due to repeated lahar sedimentation in the valley with rising aquifer pressures. A wholesale dome collapse in May 2006 on the other hand induced dilatational strain and thereby a short-term water level drop in a deeper-seated aquifer, which caused groundwater leakage from the Belham aquifer and thereby induced a delayed water level fall in the wells. The system thus responded to both gradual and rapid transient strain associated with the eruption of Soufrière Hills Volcano (Montserrat). This case study gives field evidence for theoretical predictions on volcanic drivers behind hydrological transients, demonstrating the potential of hydrological data for volcano monitoring. Interrogation of such data can provide valuable constraints on stress evolution in volcanic systems and therefore complement other monitoring systems. The presented models and inferred results are conceptually applicable to volcanic areas worldwide
    • …
    corecore