280 research outputs found

    Evidence from Cameroon reveals differences in the genetic structure and histories of chimpanzee populations

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    The history of the genus Pan is a topic of enduring interest. Chimpanzees (Pan troglodytes) are often divided into subspecies, but the population structure and genetic history of chimpanzees across Africa remain unclear. Some population genetics studies have led to speculation that, until recently, this species constituted a single population with ongoing gene flow across its range, which resulted in a continuous gradient of allele frequencies. Chimpanzees, designated here as P. t. ellioti, occupy the Gulf of Guinea region that spans southern Nigeria and western Cameroon at the center of the distribution of this species. Remarkably, few studies have included individuals from this region, hindering the examination of chimpanzee population structure across Africa. Here, we analyzed microsatellite genotypes of 94 chimpanzees, including 32 designated as P. t. ellioti. We find that chimpanzees fall into three major populations: (i) Upper Guinea in western Africa (P. t. verus); (ii) the Gulf of Guinea region (P. t. ellioti); and (iii) equatorial Africa (P. t. troglodytes and P. t. schweinfurthii). Importantly, the Gulf of Guinea population is significantly different genetically from the others, sharing a last common ancestor with the populations in Upper Guinea similar to 0.46 million years ago (mya) and equatorial Africa similar to 0.32 mya. Equatorial chimpanzees are subdivided into up to three populations occupying southern Cameroon, central Africa, and eastern Africa, which may have constituted a single population until similar to 0.10-0.11 mya. Finally, occasional hybridization may be occurring between the Gulf of Guinea and southern Cameroon population

    Incorporating psychological influences in probabilistic cost analysis

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    ABSTRACT Today's typical probabilistic cost analysis assumes an "ideal" project that is devoid of the human and organizational considerations that heavily influence the success and cost of real-world projects. In the real world "Money Allocated Is Money Spent" (MAIMS principle); cost underruns are rarely available to protect against cost overruns while task overruns are passed on to the total project cost. Realistic cost estimates therefore require a modified probabilistic cost analysis that simultaneously models the cost management strategy including budget allocation. Psychological influences such as overconfidence in assessing uncertainties and dependencies among cost elements and risks are other important considerations that are generally not addressed. It should then be no surprise that actual project costs often exceed the initial estimates and are delivered late and/or with a reduced scope. This paper presents a practical probabilistic cost analysis model that incorporates recent findings in human behavior and judgment under uncertainty, dependencies among cost elements, the MAIMS principle, and project management practices. Uncertain cost elements are elicited from experts using the direct fractile assessment method and fitted with three-parameter Weibull distributions. The full correlation matrix is specified in terms of two parameters that characterize correlations among cost elements in the same and in different subsystems. The analysis is readily implemented using standard Monte Carlo simulation tools such as @Risk and Crystal Ball. The analysis of a representative design and engineering project substantiates that today's typical probabilistic cost analysis is likely to severely underestimate project cost for probability of success values of importance to contractors and procuring activities. The proposed approach provides a framework for developing a viable cost management strategy for allocating baseline budgets and contingencies. Given the scope and magnitude of the cost-overrun problem, the benefits are likely to be significant

    Changes in the allostatic response to whole-body cryotherapy and static-stretching exercises in chronic fatigue syndrome patients vs. Healthy individuals

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    Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This study represents a comparison of the functional interrelation of fatigue and cognitive, cardiovascular and autonomic nervous systems in a group of Chronic Fatigue Syndrome (CFS) patients compared with those in healthy individuals at different stages of analysis: at baseline and after changes induced by whole-body cryotherapy (WBC) combined with a static-stretching (SS) program. The study included 32 patients (Fukuda criteria) and 18 healthy controls. Fatigue, cogni-tive, cardiovascular and autonomic function and arterial stiffness were measured before and after 10 sessions of WBC with SS. In the patients, a disturbance in homeostasis was observed. The network relationship based on differences before and after intervention showed comparatively higher stress and eccentricity in the CFS group: 50.9 ± 56.1 vs. 6.35 ± 8.72, p = 0.002, r = 0.28; and 4.8 ± 0.7 vs. 2.4 ± 1, p < 0.001, r = 0.46, respectively. Before and after intervention, in the CFS group increased fatigue was related to baroreceptor function, and baroreceptor function was in turn related to aortic stiffness, but no such relationships were observed in the control group. Differences in the network structure underlying the interrelation among the four measured criteria were observed in both groups, before the intervention and after ten sessions of whole cryotherapy with a static stretching exercise.publishersversionPeer reviewe

    Hemodynamic Response to the Head-Up Tilt Test in Patients With Syncope as a Predictor of the Test Outcome: A Meta-Analysis Approach

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    Aim: The paper presents a meta-analysis of studies comparing hemodynamic parameters: heart rate (HR), systolic blood pressure (sBP), diastolic blood pressure (dBP), and stroke volume (SV) measured during head-up tilt table test (HUTT) in patients with positive and negative HUT test outcome.Methods: Pubmed and Clinical Key databases were searched for English-only articles presenting results of biosignals measurements during tilt test in patients suffering from syncope. From 3,289 articles 13 articles published between 1997 and 2015 investigating 892 patients (467 with positive HUTT outcome and 401 with negative one) were selected.Results: There were not statistically significant differences observed between the parameters measured in supine position in patients with positive and negative test outcome [HR (p = 0.86), sBP (p = 0.32), dBP (p = 0.21), SV (p = 0.71)]. In tilt position the parameters HR and SV were significantly different when compared between the two groups of patients [HR (p = 0.02), sBP (p = 0.10), dBP (p = 0.59), SV (p = 0.0004)].Conclusions: Changes in HR and SV parameters in response to tilt test turned out to be statistically significant. In supine position the differences between patients with positive and negative test outcome were not significant, hence tilt test can be considered as necessary in the diagnosis of vasovagal syndrome

    Bloggers Behavior and Emergent Communities in Blog Space

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    Interactions between users in cyberspace may lead to phenomena different from those observed in common social networks. Here we analyse large data sets about users and Blogs which they write and comment, mapped onto a bipartite graph. In such enlarged Blog space we trace user activity over time, which results in robust temporal patterns of user--Blog behavior and the emergence of communities. With the spectral methods applied to the projection on weighted user network we detect clusters of users related to their common interests and habits. Our results suggest that different mechanisms may play the role in the case of very popular Blogs. Our analysis makes a suitable basis for theoretical modeling of the evolution of cyber communities and for practical study of the data, in particular for an efficient search of interesting Blog clusters and further retrieval of their contents by text analysis

    Effects of Sitting Callisthenic Balance and Resistance Exercise Programs on Cognitive Function in Older Participants

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    Background: Exercise training programs have the potential to improve cognitive function in older subjects. However, the majority of training programs are based on aerobic modality. In the current study, the influence of 3 months programs of sitting callisthenic balance (SCB) and resistance training (RT) on cognitive functioning and the mediating role that a change in the level of neurotrophic factors and strength in older, healthy participants plays were examined. Material and methods: Global cognitive function was examined using MoCA, short-term memory using Digit Span and Delayed Matching to Sample, set shifting using Trial Making Test Part B, speed of processing simple visual stimuli using Simple Reaction Time, decision making using Choice Reaction Time, visual attention with Visual Attention Test (VAT), tests. Strength of lower and upper limbs, neurotrophin level (irisin, brain-derived neurotrophic factor (BDNF), neurotrophin 3 (NT-3), neurotrophin 4/5 (NT 4/5) were examined. Results: Improved scores in RT vs. SCB were noted in MoCA (p = 0.02), reaction time in SRT (p = 0.02), TMT B (p = 0.03), errors committed in CRT (p = 0.04) and VAT (p = 0.02) were observed. No significant changes in the level of neurotrophic factors were observed. Changes in upper limb strength were related to changes in the number of errors committed in the SRT (p = 0.03). Lower limb strength changes explained the dynamics of the number of correct answers (p = 0.002) and errors committed (p = 0.006) in VAT. Conclusions: Both SCB and RT influenced multiple cognitive domains. The RT program improved global cognitive functioning, while no improvement was noticed in the SCB group. Decision making, visual attention and global cognitive function were improved after the RT program. Set-shifting, short-term visual memory processing speed of simple visual stimuli were improved after the SCB program, while a decrease in the processing speed of simple visual stimuli was noted in the RT group. Changes in irisin were related to set-shifting and short-term memory, while in BDNF to an improvement in the processing speed of simple visual stimuli. Resistance exercise training programs could be applied to prevent age related declines of cognitive function in healthy older subjects

    Effects of whole-body cryotherapy and static stretching are maintained 4 weeks after treatment in most patients with chronic fatigue syndrome

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    Funding Information: This article/publication is based upon work from COST Action CA15111 ”European Network on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome, EUROMENE,” supported by COST (European Cooperation in Science and Technology, weblink: www.cost.eu , access date: 09.06.2022). Publisher Copyright: © 2023 The AuthorsIn the previous study, whole-body cryotherapy (WBC)+static stretching (SS) has been shown 25 to reduce the severity of some symptoms in Chronic Fatigue Syndrome (CFS) noted just after 26 the therapy. Here we consider the effects of treatment and explore the sustainability of 27 symptom improvements at four weeks (one-month) follow-up. Twenty-two CFS patients were 28 assessed one month after WBC+SS programme. Parameters related to fatigue (Chalder 29 Fatigue Questionnaire (CFQ), Fatigue Impact Scale (FIS), Fatigue Severity Scale (FSS)), 30 cognitive function (Trial Making test part A and B (TMT A and TMT B and its difference 31 (TMT B-A)), Coding) hemodynamic, aortic stiffness (aortic systolic blood pressure (sBP 32 aortic)) and autonomic nervous system functioning were measured. TMT A, TMT B, TMT B33 A and Coding improved at one month after the WBC+SS programme. WBC+SS had a 34 significant effect on the increase in sympathetic nervous system activity in rest. WBC+SS had 35 a significant, positive chronotropic effect on the cardiac muscle. Peripheral and aortic systolic 36 blood pressure decreased one month after WBC+SS in comparison to before. Effects of 37 WBC+SS on reduction of fatigue, indicators of aortic stiffness and symptoms severity related 38 to autonomic nervous system disturbance and improvement in cognitive function were 39 maintained at one month. However, improvement in all three fatigue scales (CFQ, FIS and 40 FSS) was noted in 17 of 22 patients. In addition, ten patients were treated initially but they 41 were not assessed at 4 weeks, and are thus not included in the 22 patients who were examined 42 on follow-up. The overall effects of WBC+SS noted at one month post-treatment should be 43 interpreted with caution.publishersversionPeer reviewe

    Screening for impact of popular herbs improving mental abilities on the transcriptional level of brain transporters

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    There are a number of compounds that can modify the activity of ATP-binding cassette (ABC) and solute carrier (SLC) transporters in the blood-brain barrier (BBB). The aim of this study was to investigate the effect of natural and synthetic substances on the expression level of genes encoding transporters present in the BBB (mdr1a, mdr1b, mrp1, mrp2, oatp1a4, oatp1a5 and oatp1c1). Our results showed that verapamil caused the greatest reduction in the mRNA level while other synthetic (piracetam, phenobarbital) and natural (codeine, cyclosporine A, quercetin) substances showed a selective inhibitory effect. Moreover, extract from roots of Panax ginseng C. A. Meyer exhibited a decrease of transcription against selected transporters whereas extract from Ginkgo biloba L. leaves resulted in an increase of the expression level of tested genes except for mrp2. Extract from aerial parts of Hypericum perforatum L. was the only one to cause an increased mRNA level for mdr1 and oatp1c1. These findings suggest that herbs can play an important role in overcoming the BBB and multidrug resistance against pharmacotherapy of brain cancer and mental disorders, based on the activity of selected drug-metabolizing enzymes and transporters located in the BBB

    Cardiovascular and autonomic consequences of sleep fragmentation

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    Introduction: Sleep disruption is commonly found in normal individuals and those with sleep disorders. Risk factors for sleep fragmentation involve a combination of lifestyle, environmental, psychosocial factors and/or medical conditions. The main objective of this study was to analyse the impact of acute, induced sleep fragmentation upon autonomic cardiovascular regulation, measured by a non-invasive haemodynamic measurement technique. Material and methods: The authors analysed beat-to-beat measurements of haemodynamic and autonomic parameters at 5-time points during sleep fragmentation: 9:00 a.m. (baseline), 9:00 p.m., 00:30 a.m., 4:00 a.m., and 7:30 a.m. Differences in the mean values for chronotropic parameters, cardiac contractility, parameters related to blood pressure regulation and workload of the left ventricle, and autonomic parameters were examined in seventeen healthy male volunteers. Direct results obtained from every time point were analysed using analysis of variance with repeated measures or the Friedman rank sum test. Results: Sleep fragmentation had a significant negative impact on haemodynamic parameters related to cardiac contractility (SV p &lt; 0.001, IC p &lt; 0.001, HI p &lt; 0.001); parameters related to workload of the left ventricle (CO p &lt; 0.001, LVWI p &lt; 0.001, ACI p &lt; 0.001); parameters related to blood pressure regulation (sBP p = 0.001, TPR p &lt; 0.001); on chronotropic parameters (HR p &lt; 0.001, PEP p &lt; 0.001, LVET p &lt; 0.001) and an indicator of cardiac autonomic regulation: LF-RRI (p = 0.001). Conclusions: Acute sleep fragmentation can modify haemodynamic control and autonomic cardiovascular regulation in healthy men; the most important changes were seen in the morning hours (4:00 a.m.). Therefore, conditions of chronic sleep fragmentation (e.g. shift work, uniformed services, clinicians), might lead to disturbance in the autonomic nervous system and therefore to problems with homeostasis in the cardiovascular system. Future research is needed in standardized conditions with large-scale studies to clarify the effects of chronic sleep fragmentation

    Coffee Consumption and Blood Pressure: Results of the Second Wave of the Cognition of Older People, Education, Recreational Activities, Nutrition, Comorbidities, and Functional Capacity Studies (COPERNICUS)

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    This study examined the relationship between the frequency of coffee consumption and blood pressure over a two year follow up of a cohort of elderly people. Healthy, older people (N = 205) were examined at baseline and at two years. Participants completed physical and behavioural assessments, which included body composition, current pharmacological treatment, and frequency of coffee consumption grouped into three categories: “never to a few times per month”, “once a week to a few times per week”, and “every day”. Blood pressure (systolic (sBP), diastolic (dBP), mean (mBP), and pulse pressure (PP)) was measured at baseline and after two years. After adjusting for body composition, smoking status, age, sex, heart rate, and number of antihypertensive agents taken, participants who drank coffee everyday had a significant increase in sBP, with a mean of 8.63 (1.27; 15.77) and an mBP, with a mean of 5.55 mmHg (0.52; 10.37) after two years (t = 2.37, p = 0.02 and t = 2.17, p = 0.03, respectively) compared to participants who never or very rarely (up to a few times per month) drank coffee. DBP and PP were not affected by coffee consumption frequency in a statistically significant manner.info:eu-repo/semantics/publishedVersio
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