765 research outputs found

    How Cultural Transmission Through Objects Impacts Inferences About Cultural Evolution

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    The cross-fertilisation between biological and cultural evolution has led to an extensive borrowing of key concepts, theories, and statistical methods for studying temporal variation in the frequency of cultural variants. Archaeologists have been among the front-runners of those engaging with this endeavour, and the last 2 decades have seen a number of case studies where modes of social learning were inferred from the changing frequencies of artefacts. Here, we employ a simulation model to review and examine under-discussed assumptions shared by many of these applications on the nature of what constitutes the 'population' under study. We specifically ask (1) whether cultural transmission via 'objects' (i.e. public manifestations of cultural traits) generates distinct patterns from those expected from direct transmission between individuals and (2) whether basing inference on the frequency of objects rather than on the frequency of mental representations underlying the production of those objects may lead to biased interpretations. Our results show that the rate at which ideational cultural traits are embedded in objects, and shared as such, has a measurable impact on how we infer cultural transmission processes when analysing frequency-based archaeological data. At the same time, when cultural transmission is entirely mediated by the material representation of ideas, we argue that copying error should be interpreted as a two-step process which may occur in either one or both of embedding information in objects and retrieving it from them

    The effects of land use and topographic changes on sediment connectivity in mountain catchments

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    Understanding the evolution of sediment connectivity associated with different land use and topographic changes is a prerequisite for a better understanding of sediment budgets and sediment transport processes. We used the Index of Sediment Connectivity (IC) developed by Cavalli et al. (2013) based on the original approach by Borselli et al. (2008) to study the effects of decadal-scale land use and topographic changes on sediment connectivity in mountain catchments. The input variables of the IC (i.e. land cover and topography) were derived from historical aerial photos using Structure from Motion-Multi View Stereo algorithms (SfM-MVS). The method was applied in different sub-catchments of the Upper River Cinca Catchment (Central Pyrenees), representative of three scenarios: (a) Land cover changes; (b) Topographic changes in agricultural fields (terracing); and (c) Topographic changes associated with infrastructure (road construction). In terms of land cover changes, results show that although connectivity is increased in some areas due to the establishment of new field crops, for most of the study area connectivity decreased due to afforestation caused by rural abandonment. Topographic changes due to the establishment of agricultural terraces affected connectivity to a larger degree than land cover changes. Terracing generally reduced connectivity due to the formation of flat areas in step-slopes, but in certain points, an increase in connectivity caused by the topographic convergence produced by terraces was observed. Finally, topographic changes associated with road construction greatly modified surface flow directions and the drainage network, resulting in changes in connectivity that may affect erosional processes nearby. The methodology used in this paper allows to study the effects of real decadal-scale land use and topographic changes on sediment connectivity and also evaluating and disentangling those changes. Furthermore, this approach can be a useful tool to identify potential risks associated with morphological and land use changes, involving road infrastructures

    Comparing Three Instructional Modes for an Engineering Economy Course

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    This study compares three instructional modes in an “Engineering Economy” course: online, face-to-face (FtF), and flipped. Engineering Economy is a core course in this study and incorporates students with diverse backgrounds from different engineering majors. To discern the relation between student characteristics and teaching modality, an online questionnaire was designed for each mode and distributed over a two-year period. Data was collected and several statistical analyses were conducted to study the relationship between pedagogical delivery modes and various student-based factors such as gender, age, course load, living distance from campus, computer skills, work status, and first language. Students’ performance, persistence, and knowledge self-evaluation were also compared in different modes. The statistical analyses of data at 95% confidence level show that among all the factors, only the ratio of native English speakers, course load and work category differ significantly in different instructional modes. No statistically significant difference was observed between different modes for other factors

    Debris flows in the eastern Italian Alps: seasonality and atmospheric circulation patterns

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    Abstract. The work examines the seasonality and large-scale atmospheric circulation patterns associated with debris-flow occurrence in the Trentino–Alto Adige region (eastern Italian Alps). Analysis is based on classification algorithms applied to a uniquely dense archive of debris flows and hourly rain gauge precipitation series covering the period 2000–2009. Results highlight the seasonal and synoptic forcing patterns linked to debris flows in the study area. Summer and fall season account for 92% of the debris flows in the record, while atmospheric circulation characterized by zonal west, mixed and meridional south and southeast (SE–S) patterns account for 80%. Both seasonal and circulation patterns exhibit geographical preference. In the case of seasonality, there is a strong north–south separation of summer–fall dominance, while spatial distribution of dominant circulation patterns exhibits clustering, with both zonal west and mixed patterns prevailing in the northwest and central east part of the region, while the southern part relates to meridional south and southeast pattern. Seasonal and synoptic pattern dependence is pronounced also on the debris-flow-triggering rainfall properties. Examination of rainfall intensity–duration thresholds derived for different data classes (according to season and synoptic pattern) revealed a distinct variability in estimated thresholds. These findings imply a certain control on debris-flow events and can therefore be used to improve existing alert systems

    Brief Communication: A new testing field for debris flow warning systems

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    Abstract. A permanent field installation for the systematic test of debris flow warning systems and algorithms has been equipped on the eastern Italian Alps. The installation was also designed to produce didactic videos and it may host informative visits. The populace education is essential and should be envisaged in planning any research on hazard mitigation interventions: this new installation responds to this requirement and offers an example of integration between technical and informative needs. The occurrence of a debris flow in 2014 allowed the first tests of a new warning system under development and to record an informative video on its performances. This paper will provide a description of the installation and an account of the first technical and informative results obtained

    Impacto da temperatura e fotoperíodo no desenvolvimento ovariano e oviposição de traça-das-crucíferas.

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    A migração é um fenômeno que pode ocorrer em algumas espécies de insetos e ela geralmente começa quando os ovários não estão desenvolvidos, ou o estão parcialmente. Para traça-das-crucíferas, Plutella xylostella (Lepidoptera: Yponomeutidae) já foi observado que a densidade larval afetou o grau de desenvolvimento ovariano. Neste trabalho foi determinado o impacto da temperatura e do fotoperíodo no desenvolovimento ovariano e na oviposição do inseto. Larvas de quarto estágio foram criadas individualmente em placas de Petri à temperaturas de 14 e 25ºC e fotofase de 8 e 14 h. As fêmeas recém-emergidas foram mortas em um freezer, dissecadas sob um microscópio e o ovário observado. Para determinar o impacto da temperatura sobre a oviposição do inseto, larvas de quarto estágio foram criadas a temperaturas de 14 e 25ºC e, quando os machos e fêmeas emergiram, casais foram colocados individualmente em placas de Petri. Foi determinado o período de pré-oviposição e o número de ovos depositados no primeiro dia. Os resultados mostraram que o grau de desenvolvimento ovariano não foi afetado pela temperatura e fotoperíodo empregados, indicando que estes fatores não afetaram o potencial migratório da espécie. Fêmeas criadas a 25ºC depositaram seus ovos dois dias após a emergência enquanto que fêmeas criadas a 14ºC o fizeram aos cinco dias, sugerindo que o período de pré-oviposição é aumentado a baixas temperaturas. O impacto destes resultados sobre a migração e dispersão da TDC são discutidos

    Neuromuscular electrical stimulation restores upper limb sensory-motor functions and body representations in chronic stroke survivors

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    Background: A conventional treatment outcome is suboptimal for sensory impairments in stroke patients. Novel approaches based on electrical stimulation or robotics are proposed as an adjuvant for rehabilitation, though their efficacy for motor, sensory, and body representation recovery have not been tested. Methods: Sixty chronic stroke patients with unilateral motor deficits were included in a pseudo-randomized open-label multi-arm control trial (ClinicalTrials.gov: NCT03349138). We tested the effects of a robotic glove (GloReha [GR]) and a new neuromuscular electrical stimulation system (Helping Hand [HH]) and compared them with conventional treatment (CT) in restoring motor and sensory functions and the affected limb perception. HH was designed to concurrently deliver peripheral motor activation and enhanced cutaneous sensation. Patients were split in four dose-matched groups: CT, GR, HH, and GRHH (receiving 50% GR and 50% HH). Assessments were performed at inclusion, halfway, end of treatment (week 9), and follow-up (week 13). Findings: HH provided an earlier benefit, quantified by the Motricity Index (MI), than GR. At the end of the treatment, the amelioration was higher in groups GRHH and HH and extended to somatosensory functions. These benefits persisted at the follow-up. GRHH and HH also improved the perceived dimensions and altered feeling toward the affected limb. Interestingly, the reduction of altered feelings correlated with MI improvements and depended on the amount of HH. Conclusions: We suggest that HH concurrently stimulates sensory and motor systems by generating an enhanced cutaneous sensation, coherent in location with the elicited motor recruitment, leading to ameliorated sensorimotor functions and bodily perceptions in stroke patients. Funding: This work was supported by a Foundation advised by CARIGEST, by Fondazione CARIPLO, by the SNSF NCCR Robotics, and by the Bertarelli Foundation

    Approximate Bayesian Computation of radiocarbon and paleoenvironmental record shows population resilience on Rapa Nui (Easter Island).

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    Examining how past human populations responded to environmental and climatic changes is a central focus of the historical sciences. The use of summed probability distributions (SPD) of radiocarbon dates as a proxy for estimating relative population sizes provides a widely applicable method in this research area. Paleodemographic reconstructions and modeling with SPDs, however, are stymied by a lack of accepted methods for model fitting, tools for assessing the demographic impact of environmental or climatic variables, and a means for formal multi-model comparison. These deficiencies severely limit our ability to reliably resolve crucial questions of past human-environment interactions. We propose a solution using Approximate Bayesian Computation (ABC) to fit complex demographic models to observed SPDs. Using a case study from Rapa Nui (Easter Island), a location that has long been the focus of debate regarding the impact of environmental and climatic changes on its human population, we find that past populations were resilient to environmental and climatic challenges. Our findings support a growing body of evidence showing stable and sustainable communities on the island. The ABC framework offers a novel approach for exploring regions and time periods where questions of climate-induced demographic and cultural change remain unresolved

    Spatial dimensions of water quality value in New England river networks

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    Households’ willingness to pay (WTP) for water quality improvements—representing their economic value—depends on where improvements occur. Households often hold higher values for improvements close to their homes or iconic areas. Are there other areas where improvements might hold high value to individual households, do effects on WTP vary by type of improvement, and can these areas be identified even if they are not anticipated by researchers? To answer these questions, we integrated a water quality model and map-based, interactive choice experiment to estimate households’ WTP for water quality improvements throughout a river network covering six New England states. The choice experiment was implemented using a push-to-web survey over a sample of New England households. Voting scenarios used to elicit WTP included interactive geographic information system (GIS) maps that illustrated three water quality measures at various zoom levels across the study domain. We captured data on how respondents maneuvered through these maps prior to answering the value-eliciting questions. Results show that WTP was influenced by regionwide quality improvements and improvements surrounding each respondent’s home, as anticipated, but also by improvements in individualized locations identifiable via each respondent’s map interactions. These spatial WTP variations only appear for low-quality rivers and are focused around particular areas of New England. The study shows that dynamic map interactions can convey salient information for WTP estimation and that predicting spatial WTP heterogeneity based primarily on home or iconic locations, as typically done, may overlook areas where water quality has high value. Copyright © 2023 the Author(s)
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