18 research outputs found

    Climate and habitat configuration limit range expansion and patterns of dispersal in a non-native lizard

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    Invasive species are one of the main causes of biodiversity loss worldwide. As introduced, populations increase in abundance and geographical range, so does the potential for negative impacts on native communities. As such, there is a need to better understand the processes driving range expansion as species become established in recipient landscapes. Through an investigation into capacity for population growth and range expansion of introduced populations of a non‐native lizard (Podarcis muralis), we aimed to demonstrate how multi‐scale factors influence spatial spread, population growth, and invasion potential in introduced species. We collated location records of P. muralis presence in England, UK through data collected from field surveys and a citizen science campaign. We used these data as input for presence‐background models to predict areas of climate suitability at a national‐scale (5 km resolution), and fine‐scale habitat suitability at the local scale (2 m resolution). We then integrated local models into an individual‐based modeling platform to simulate population dynamics and forecast range expansion for 10 populations in heterogeneous landscapes. National‐scale models indicated climate suitability has restricted the species to the southern parts of the UK, primarily by a latitudinal cline in overwintering conditions. Patterns of population growth and range expansion were related to differences in local landscape configuration and heterogeneity. Growth curves suggest populations could be in the early stages of exponential growth. However, annual rates of range expansion are predicted to be low (5–16 m). We conclude that extensive nationwide range expansion through secondary introduction is likely to be restricted by currently unsuitable climate beyond southern regions of the UK. However, exponential growth of local populations in habitats providing transport pathways is likely to increase opportunities for regional expansion. The broad habitat niche of P. muralis, coupled with configuration of habitat patches in the landscape, allows populations to increase locally with minimal dispersal

    Response behaviour of native lizards and invading wall lizard to interspecific scent: implications for invasion success

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    The human-assisted movement of species beyond their native range facilitates novel interactions between invaders and native species that can determine whether an introduced species becomes invasive and the nature of any consequences for native communities. Avoiding costly interactions through recognition and avoidance can be compromised by the naïvety of native species to novel invaders and vice versa. We tested this hypothesis using the common wall lizard, Podarcis muralis, and the native lizard species with which it may now interact in Britain (common lizard, Zootoca vivipara, sand lizard, Lacerta agilis) and on Vancouver Island (northern alligator lizard, Elgaria coerulea) by exploring species' responses (tongue flicks, avoidance behaviour) to heterospecific scent cues in controlled experiments. The tongue flick response of P. muralis depended on the different species’ scent, with significantly more tongue flicks directed to E. coerulea scent than the other species and the control. This recognition did not result in any other behavioural response in P. muralis (i.e. attraction, aggression, avoidance). Lacerta agilis showed a strong recognition response to P. muralis scent, with more tongue flicks occurring close to the treatment stimuli than the control and aggressive behaviour directed towards the scent source. Conversely, Z. vivipara spent less time near P. muralis scent cues than the control but its tongue flick rate was higher towards this scent in this reduced time, consistent with an avoidance response. There was no evidence of E. coerulea recognition of P. muralis scent in terms of tongue flicks or time spent near the stimuli, although the native species did show a preference for P. muralis-scented refuges. Our results suggest a variable response of native species to the scent of P. muralis, from an avoidance response by Z. vivipara that mirrors patterns of exclusion observed in the field to direct aggression observed in L. agilis and an ambiguous reaction from E. coerulea which may reflect a diminished response to a cue with a low associated cost. These results have significant implications for the invasive success and potential impacts of introduced P. muralis populations on native lizards

    Importance of exercise and motor fitness in 11–13 year old primary school children in liechtenstein

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    Several studies have shown that the behavioral pattern in exercise and motor fitness of children has changed dramatically in the last two generations. Because childhood is a very important period of life, the promotion of physical activity (PA) has been identified as a major public health priority. Therefore the aim of this study was to observe the fitness level and the importance of PA among 5th grade pupils in Liechtenstein. This cross-sectional study was carried out from March to June 2007. A total of 313 children (aged 11.8 ± 0.6 years) were randomly selected. PA and socio-demographic data were acquired with a short questionnaire, the motor fitness with a test battery, consisting of eight items. In summary, the physical performance of all the children is satisfactory, but with obvious deficits in coordination, flexibility and basic motor skills. Children’s general fitness was significantly higher among those, who were members of sports clubs than non members (p<.05). A high level of PA in free time was associated with better motor fitness (p < .001). According to other studies, this survey illustrates the controversial findings of a high participation in sports of school children in their free time activities but at the same time increasing motor disorders

    Expertise-related functional brain network efficiency in healthy older adults

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    BACKGROUND: In view of age-related brain changes, identifying factors that are associated with healthy aging are of great interest. In the present study, we compared the functional brain network characteristics of three groups of healthy older participants aged 61-75 years who had a different cognitive and motor training history (multi-domain group: participants who had participated in a multi-domain training; visuomotor group: participants who had participated in a visuomotor training; control group: participants with no specific training history). The study's basic idea was to examine whether these different training histories are associated with differences in behavioral performance as well as with task-related functional brain network characteristics. Based on a high-density electroencephalographic measurement one year after training, we calculated graph-theoretical measures representing the efficiency of functional brain networks. RESULTS: Behaviorally, the multi-domain group performed significantly better than the visuomotor and the control groups on a multi-domain task including an inhibition domain, a visuomotor domain, and a spatial navigation domain. In terms of the functional brain network features, the multi-domain group showed significantly higher functional connectivity in a network encompassing visual, motor, executive, and memory-associated brain areas in the theta frequency band compared to the visuomotor group. These brain areas corresponded to the multi-domain task demands. Furthermore, mean connectivity of this network correlated positively with performance across both the multi-domain and the visuomotor group. In addition, the multi-domain group showed significantly enhanced processing efficiency reflected by a higher mean weighted node degree (strength) of the network as compared to the visuomotor group. CONCLUSIONS: Taken together, our study shows expertise-dependent differences in task-related functional brain networks. These network differences were evident even a year after the acquisition of the different expertise levels. Hence, the current findings can foster understanding of how expertise is positively associated with brain functioning during aging

    Physical activity and screen time in children who survived cancer: A report from the Swiss Childhood Cancer Survivor Study

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    BACKGROUND Physical activity (PA) can reduce the risk of chronic adverse health conditions in childhood cancer survivors. We examined PA and sedentary screen time behavior in a nationwide study in Switzerland. PROCEDURES The Swiss Childhood Cancer Survivor Study sent questionnaires to parents of all Swiss resident ≥5-year survivors diagnosed between 1995 and 2010. We assessed PA including compulsory school sport, recreational sport, commuting to school, and time spent with screen media in those aged 5-15 years, and compared results with international recommendations. RESULTS We included 766 survivors with a median age at diagnosis of 2.8 (interquartile range 1.4-5.0) years and a median age at study of 12.5 (10.0-14.3) years. Median PA time was 7.3 (4.8-10.0) h/week and median screen time was 82 (45-120) min/day. Compulsory school sport hours and walking or cycling to school contributed significantly to total PA. Note that 55% of survivors met PA and 68% screen time recommendations. PA was lower for children living in regions of Switzerland speaking French or Italian compared to German, and for those who had a relapse or musculoskeletal/neurological conditions. Screen time was higher in males, children with lower parental education, and a migration background. CONCLUSIONS PA and sedentary screen watching were associated with social factors, and PA also with clinical risk factors. Structural preventions that afford active commuting to school and sufficient school sport are essential, as is counseling vulnerable survivor groups such as those with musculoskeletal and neurological problems, and those who have had a relapse

    Imaging-Based Prevalence of Oligometastatic Disease: A Single-Center Cross-Sectional Study

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    PURPOSE Oligometastatic disease refers to a distinct state in patients with cancer characterized by a low metastatic burden, with diagnosis being informed by a limited number of distant metastases in radiologic imaging. However, oligometastasis remains poorly understood in terms of its biology and prevalence in the metastatic cascade. In the absence of clinically viable molecular biomarkers, this study examined the prevalence of oligometastasis using oncological imaging. METHODS AND MATERIALS This study is based on all consecutive [fluorine-18]-fluorodeoxyglucose (FDG)- and [gallium-68]-prostate specific membrane antigen (PSMA)-positron emission tomography (PET) scans conducted at our cancer center between January and December 2020. We identified and analyzed all PET scans from patients with a maximum of 5 distant metastases from a solid malignancy and also reviewed concurrent cranial magnetic resonance imaging (cMRI) imaging in all candidate patients. Data on the number and sites of metastases were extracted from the imaging reports and verified on imaging studies in case of uncertainties. RESULTS In total, 7000 PET scans were analyzed, of which 1155 were performed in unique metastatic patients, and 637 patients showed extracranial oligometastatic disease (55%). Concurrent cMRI scans were available for 20% (130/637) of extracranial oligometastatic patients, 36 of which proved to be polymetastatic after combined PET and cMRI analysis. Prevalence of oligometastatic disease was influenced by primary tumor histology and was most frequent in pancreatic, liver and gallbladder cancers (59%), but was least frequent in cancer of unknown primary (26%). In 72% of oligometastatic cases, only 1 or 2 metastases were detected. Bone/soft tissue metastases were the most common sites of distant metastasis (41%). About 75% of patients had metachronous oligometastatic disease. CONCLUSIONS Our analysis suggests that about half of patients with metastatic cancer are characterized by a limited tumor burden detectable on PET and cMRI imaging. This finding warrants intensified research efforts to better understand the biology of oligometastatic disease and to optimize multidisciplinary treatment strategies

    Upper limb movement quality measures: comparing IMUs and optical motion capture in stroke patients performing a drinking task

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    Introduction: Clinical assessment of upper limb sensorimotor function post-stroke is often constrained by low sensitivity and limited information on movement quality. To address this gap, recent studies proposed a standardized instrumented drinking task, as a representative daily activity combining different components of functional arm use. Although kinematic movement quality measures for this task are well-established, and optical motion capture (OMC) has proven effective in their measurement, its clinical application remains limited. Inertial Measurement Units (IMUs) emerge as a promising low-cost and user-friendly alternative, yet their validity and clinical relevance compared to the gold standard OMC need investigation. Method: In this study, we conducted a measurement system comparison between IMUs and OMC, analyzing 15 established movement quality measures in 15 mild and moderate stroke patients performing the drinking task, using five IMUs placed on each wrist, upper arm, and trunk. Results: Our findings revealed strong agreement between the systems, with 12 out of 15 measures demonstrating clinical applicability, evidenced by Limits of Agreement (LoA) below the Minimum Clinically Important Differences (MCID) for each measure. Discussion: These results are promising, suggesting the clinical applicability of IMUs in quantifying movement quality for mildly and moderately impaired stroke patients performing the drinking task.ISSN:2673-253
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