Statistical power analysis with microsoft excel: normal tests for one or two means as a prelude to using non-central distributions to calculate power

This article presents statistical power analysis (SPA) based on the normal distribution using Excel, adopting textbook and SPA approaches. The objective is to present the latter in a comparative way within a framework that is familiar to textbook level readers, as a first step to understand SPA with other distributions. The analysis focuses on the case of the equality of the means of two populations with equal variances for independent samples with the same size. This is the situation adopted as case 0 by Cohen (1988), a pioneer in the subject, to develop his set of tables and so, the present article can be seen as an introduction to Cohen's methodology applied to tests based on samples from normal populations. We also discuss how to extend the calculation to cases with other characteristics (cases 1 to 4), similarly to what Cohen proposes, as well as a brief discussion about the advantages and shortcomings of Excel. We teach mainly in the area of business and economics, which determines the scope of our analysis.info:eu-repo/semantics/publishedVersio

The clustering conditions for managing creative tourism destinations: the Alqueva region case, Portugal

This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this recordThe paper discusses conditions and format of a cluster model to support the management of a potential creative tourism destination in a setting where regional cross-sectoral collaboration is lacking. Creative tourism development requires a flexible framework and a healthy collaboration environment, more so when associated with resources shared by several stakeholders. This article focuses on the tourism potential of archaeological knowledge discovered during the environmental impact assessment of the Alqueva dam (Alentejo, Portugal). Interviews were conducted with 38 regional actors in the tourism and heritage sectors, as well as the dam developers and the companies responsible for archaeological interventions. Findings indicate that the lack of specific local policy addressing archaeological heritage hampers its potential use for tourism development, which is further aggravated by the absence of stakeholder communication and cooperation. A conceptual cluster model for the management of creative tourism destinations based on heritage resources and other local resources is proposed.Portuguese national funding agency for Science, Research and Technology (FCT

Urban stream assessment system (UsAs): An integrative tool to assessbiodiversity, ecosystem functions and services

©. This manuscript version is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/ This document is the Published Manuscript version of a Published Work that appeared in final form in [Ecological Indicators]. To access the final edited and published work see[https://doi.org/10.1016/j.ecolind.2020.106980

Stay with the flow: How macroinvertebrate communities recover during the rewetting phase in Alpine streams affected by an exceptional drought

Droughts are affecting an increasing number of lotic ecosystems worldwide due to the combined effects of climatic and anthropogenic pressures. Unlike naturally intermittent rivers, where the drying phase is a part of the annual flow regime, water scarcity in Alpine rivers represents a relatively recent phenomenon and, therefore, a major threat for the biodiversity of these lotic ecosystems. However, Alpine stream community response to drought is still poorly investigated. Here, we assess the recovery of macroinvertebrates in two Alpine streams after a supraseasonal drought. As water returned, a total of 10 sampling sessions were carried out, and temporal patterns in diversity, density, and taxonomic composition of benthic communities, as well as in the percentage of functional feeding groups, were investigated. We found that the resistance of invertebrate communities in Alpine streams is generally low: drought markedly reduced the diversity and density of macroinvertebrates. Conversely, our results suggest that the passive dispersal by drift from the upstream river sections seems the most probable mechanism promoting the post-drought recovery. Nevertheless, this resilience ability appears to be stream specific and influenced by intrinsic stream characteristics, including the flow permanence and distance from the nearest upstream perennial reach. This work sheds light on the ecological consequences of droughts on macroinvertebrate communities. As flow intermittency in Alpine areas is expected to intensify under current global change scenarios, results of this study provide important information to predict changes in the taxonomic composition and diversity of macroinvertebrate communities

Invertebrados

Os invertebrados aquáticos são importantes elementos dos ecossistemas ribeirinhos. Possuem adaptações e estratégias diversificadas para fazer face à multiplicidade de condições que se fazem sentir nestes ambientes, nomeadamente de velocidade de corrente, oxigénio dissolvido, tipo e quantidade de alimento disponível, entre outros. Desempenham importantes funções nestes ecossistemas garantindo a sua integridade. Por exemplo, estabelecem a ligação energética entre os níveis inferiores e superiores das cadeias alimentares, por se alimentarem de algas, microorganismos e detritos orgânicos, que entram nos ambientes lóticos provenientes do meio terrestre, e servirem de alimento a predadores (outros invertebrados, peixes, aves, anfíbios). Devido às diferentes sensibilidades das várias espécies às condições externas, as comunidades de invertebrados presentes num local funcionam como bioindicadores da integridade ecológica destes ecossistemas lóticos. Em Portugal, os invertebrados aquáticos bentónicos têm sido dos elementos biológicos mais estudados. Desde os anos 1980 foram examinados os padrões regionais de distribuição e ecologia dos invertebrados bentónicos, identificadas as principais fontes de perturbação destas comunidades e avaliada a sua aplicação como bioindicadores, contribuindo para o desenvolvimento de métodos para a avaliação da sua integridade estrutural e funcional, ajustados às condições do país. Destaca-se ainda a ocorrência de endemismos de invertebrados aquáticos em Portugal continental e ilhas, alguns dos quais em declínio dadas as múltiplas ameaças aos seus habitats, potenciado pela crescente introdução de espécies de invertebrados invasores. Palavras-chave: adaptações, bioindicadores, diversidade, endémicos, insetos aquáticos, invasore