Photometric Redshift Requirements for Self-Calibration of Cluster Dark Energy Studies

The ability to constrain dark energy from the evolution of galaxy cluster counts is limited by the imperfect knowledge of cluster redshifts. Ongoing and upcoming surveys will mostly rely on redshifts estimated from broad-band photometry (photo-z's). For a Gaussian distribution for the cluster photo-z errors and a high cluster yield cosmology defined by the WMAP 1 year results, the photo-z bias and scatter needs to be known better than 0.003 and 0.03, respectively, in order not to degrade dark energy constrains by more than 10% for a survey with specifications similar to the South Pole Telescope. Smaller surveys and cosmologies with lower cluster yields produce weaker photo-z requirements, though relative to worse baseline constraints. Comparable photo-z requirements are necessary in order to employ self-calibration techniques when solving for dark energy and observable-mass parameters simultaneously. On the other hand, self-calibration in combination with external mass inferences helps reduce photo-z requirements and provides important consistency checks for future cluster surveys. In our fiducial model, training sets with spectroscopic redshifts for ~5%-15% of the detected clusters are required in order to keep degradations in the dark energy equation of state lower than 20%.Comment: 18 pages, 8 figures, submitted to PR

Super-sample covariance approximations and partial sky coverage

Super-sample covariance (SSC) is the dominant source of statistical error on large scale structure (LSS) observables for both current and future galaxy surveys. In this work, we concentrate on the SSC of cluster counts, also known as sample variance, which is particularly useful for the self-calibration of the cluster observable-mass relation; our approach can similarly be applied to other observables, such as galaxy clustering and lensing shear. We first examined the accuracy of two analytical approximations proposed in the literature for the flat sky limit, finding that they are accurate at the 15% and 30-35% level, respectively, for covariances of counts in the same redshift bin. We then developed a harmonic expansion formalism that allows for the prediction of SSC in an arbitrary survey mask geometry, such as large sky areas of current and future surveys. We show analytically and numerically that this formalism recovers the full sky and flat sky limits present in the literature. We then present an efficient numerical implementation of the formalism, which allows fast and easy runs of covariance predictions when the survey mask is modified. We applied our method to a mask that is broadly similar to the Dark Energy Survey footprint, finding a non-negligible negative cross-z covariance, i.e. redshift bins are anti-correlated. We also examined the case of data removal from holes due to, for example bright stars, quality cuts, or systematic removals, and find that this does not have noticeable effects on the structure of the SSC matrix, only rescaling its amplitude by the effective survey area. These advances enable analytical covariances of LSS observables to be computed for current and future galaxy surveys, which cover large areas of the sky where the flat sky approximation fails.Comment: 14 pages, 10 figures. Updated to match version published in Astronomy & Astrophysic

Self-Calibration of Cluster Dark Energy Studies: Observable-Mass Distribution

The exponential sensitivity of cluster number counts to the properties of the dark energy implies a comparable sensitivity to not only the mean but also the actual_distribution_ of an observable mass proxy given the true cluster mass. For example a 25% scatter in mass can provide a ~50% change in the number counts at z~2 for the upcoming SPT survey. Uncertainty in the scatter of this amount would degrade dark energy constraints to uninteresting levels. Given the shape of the actual mass function, the properties of the distribution may be internally monitored by the shape of the_observable_ mass function. An arbitrary evolution of the scatter of a mass-independent Gaussian distribution may be self-calibrated to allow a measurement of the dark energy equation of state of Delta w ~0.1. External constraints on the mass_variance_ of the distribution that are more accurate than Delta var < 0.01 at z~1 can further improve constraints by up to a factor of 2. More generally, cluster counts and their sample variance measured as a function of the observable provide internal consistency checks on the assumed form of the observable-mass distribution that will protect against misinterpretation of the dark energy constraints.Comment: 6 pages, 6 figures, submitted to PR

Magnification Effects on Source Counts and Fluxes

We consider the effect of lensing magnification on high redshift sources in the case that magnification varies on the sky, as expected in wide fields of view or within observed galaxy clusters. We give expressions for number counts, flux and flux variance as integrals over the probability distribution of the magnification. We obtain these through a simple mapping between averages over the observed sky and over the magnification probability distribution in the source plane. Our results clarify conflicting expressions in the literature and can be used to calculate a variety of magnification effects. We highlight two applications: 1. Lensing of high-z galaxies by galaxy clusters can provide the dominant source of scatter in SZ observations at frequencies larger than the SZ null. 2. The number counts of high-z galaxies with a Schechter-like luminosity function will be changed at high luminosities to a power law, with significant enhancement of the observed counts at L > 10 L*.Comment: 5 pages, 2 figures; accepted for publication in MNRA

First record of the genus Eumunida Smith, 1883 (Crustacea, Decapoda, Eumunididae) from the southwestern Atlantic, with the description of a new species

Eumunida picta Smith, 1883, was considered for over a century an amphi-Atlantic species and the only representative of the genus in the Atlantic Ocean, until being split into three species: E.&nbsp;picta sensu&nbsp;stricto (from the northwestern Atlantic), E.&nbsp;bella de Saint Laurent &amp; MacPherson, 1990 and E.&nbsp;squamifera de Saint Laurent &amp; MacPherson, 1990 (from the northeastern and southeastern Atlantic, respectively). Eumunida is now expanded to include a new species, E.&nbsp;notialis, from off the Brazilian coast. Hence, this is the first record of Eumunida and Eumunididae from the southwestern Atlantic. The new species differs from all its Atlantic counterparts in having (1)&nbsp;four hepatic spines; (2)&nbsp;two carapace inframarginal spines; (3)&nbsp;the distal end of the antennal acicle nearly reaching to the articulation between fourth and fifth antennal segments; and (4)&nbsp;the anterolateral spine of the second pleonal tergite obsolete

Phyllodocida (Annelida, Polychaeta) of the North East Atlantic as a model for the investigation of cryptic species

Tese de doutoramento em Biology (especialização em Integral Management of the Sea)Molecular techniques have been effective in signalling potential hidden diversity in species displaying similar morphology and presumed widespread distribution. In this study, members of Phyllodocida collected along European coasts were used as a model taxon to investigate this topic, by employing a combination of multi-locus molecular data (mtCOI-5P, 16SrRNA, ITS regions and 28SrRNA), together with morphological and morphometric examination. This work identified a large number of undescribed cryptic lineages within 6 morphospecies, namely: Eumida sanguinea (22 Molecular Operational Taxonomic Units - MOTUs); Eulalia clavigera (9 MOTUs); Hediste diversicolor (5 MOTUs); Platynereis dumerilii (10 MOTUs); Perinereis cultrifera (14 MOTUs) and Trypanosyllis zebra (10 MOTUs). In total 70 lineages were uncovered, of which 43 are unique to this work. Five of these morphospecies have a dedicated chapters where an integrative approach allowed the description of 13 new species to science and the clarification of ambiguities regarding previously descriptions. The Macaronesian islands and especially, the western part of the Mediterranean Sea, are hotspots of cryptic diversity, with a total of 10 and 30 unique lineages for each region, respectively. Mediterranean MOTUs appear to be genetically closer to the ones from Macaronesia islands, instead of the NE Atlantic lineages. A total of 2171 new sequences (1012 COI, 307 16S, 320 ITS and 532 28S) were added to the reference libraries (GenBank and BOLD systems) and will be publicly available upon publication in peer-reviewed journals. Upon minute morphological examination of the specimens, it become apparent that several lineages with obvious morphological differences have been overlooked in the literature, being commonly misidentified to the morphologically closer described species. Morphological stasis was challenged, since it appears that the older the ancestral split resulting from the different geological event periods, the higher is the probability of finding slight phenotypic disparities in cryptic lineages, previously thought to be morphological identical. Evidence for this can be seen in the deep divergence between major phylogenetic clades within some of the analysed species complex, and the perfect match of each clade to the specific morphological variation (e.g. complexes within Perinereis, Platynereis and Eulalia). In spite of these contributes, the analyses indicated that only 11% of the existing Phyllodocida species have DNA barcodes publicly available. Naming molecular lineages which lacked enough specimens with structural integrity, further sampling in subtidal regions and additional bio-informatic tools to explore the cryptic phenomena from an evolutionary and phylogeographic point of view is desirable in future works.Técnicas moleculares têm vindo a ser eficazes na sinalização de diversidade oculta em espécies com uma ampla distribuição geográfica. Nesta tese, membros dos Phyllodocida coletados ao longo das costas europeias foram utilizados como um táxon modelo para investigar espécies crípticas, usando uma combinação de dados moleculares multi-locus (mtCOI-5P, rRNA16S, regiões ITS e rRNA28S), morfológicos e morfométricos. Este estudo identificou um grande número de linhagens crípticas não descritas em 6 morfo-espécies distintas: Eumida sanguinea (22 Unidades moleculares taxonómicas operacionais - MOTUs); Eulalia clavigera (9 MOTUs); Hediste diversicolor (5 MOTUs); Platynereis dumerilii (10 MOTUs); Perinereis cultrifera (14 MOTUs) e Trypanosyllis zebra (10 MOTUs). No total, foram descobertas 70 linhagens, das quais 43 aparentam ser exclusivas deste trabalho. Cinco dessas morfo espécies têm nesta tese um capítulo dedicado, onde uma abordagem integrativa permitiu a descrição de 13 novas espécies para a ciência e a remoção de ambiguidades em relação a descrições anteriores. As ilhas da Macaronésia e a parte ocidental do Mar Mediterrâneo, são hotspots de especiação críptica, tendo-se encontrado um total de 10 e 30 linhagens únicas para cada região, respetivamente. MOTUs mediterrâneos aparentam ser geneticamente mais próximos das ilhas da Macaronésia, com as linhagens do Nordeste Atlântico aparentando ser mais distantes. Um total de 2171 novas sequencias (1012 COI, 307 16S, 320 ITS e 532 28S) foram adicionadas às bibliotecas de referência (GenBank e BOLD) e estarão disponíveis publicamente após publicação. Ao examinar mais detalhadamente o grau real de semelhança morfológica entre algumas destas supostas linhagens crípticas, fica claro que um numero considerável possui diferenças morfológicas que foram negligenciadas e erroneamente identificadas. A estase morfológica foi desafiada, uma vez que parece que quanto mais antiga a divisão ancestral resultante dos diferentes períodos geológicos, maior é a probabilidade de encontrar pequenas disparidades fenotípicas em linhagens que inicialmente aparentavam ser morfologicamente idênticas. A evidência disso pode ser vista na divergência profunda entre os principais clados filogenéticos em alguns dos complexos aqui analisados e a combinação perfeita de cada clado com uma variação morfológica específica (por exemplo, nos complexos Perinereis, Platynereis e Eulalia). Além do mais, verificou-se neste estudo que apenas 11% das espécies existentes na ordem dos Phyllodocida têm códigos de barra de ADN disponíveis ao público. Linhagens moleculares por nomear, mais amostragens em regiões subtidais e ferramentas bioinformáticas adicionais são necessárias para continuar a explorar este fenômeno críptico do ponto de vista evolutivo e filogeográfico.I am grateful to the Portuguese Foundation for Science and Technology (FCT) for supporting my PhD grant SFRH/BD/131527/2017, hosted by the University of Minho (Portugal), the University of Aveiro (Portugal) and University of Gothenburg (Sweden) in the scope of the PhD programme in Marine Science, Technology and Management (Do*Mar), specialization in Integral Management of the Sea. I also received financial support from the DNAqua-Net STSM grant "Rich and hidden biodiversity not yet barcoded in the Canary archipelago (Spain) as an opportunity to enrich the DNA barcode reference library for European polychaetes", under the EU Cost action CA15219 - Developing new genetic tools for bioassessment of aquatic ecosystems in Europe. The research leading to these results also received partial funding, from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 730984, ASSEMBLE Plus project (application n. 8229, 4th CALL, "Crypticism in the marine realm: DNA barcode-based outlook into selected invertebrate taxa of the Eastern Mediterranean"). I would like to thank the project “The NextSea: Next generation monitoring of coastal ecosystems in a scenario of global change” (NORTE-01-0145-FEDER-000032), supported by NORTE 2020 (Norte Portugal Regional Operational Programme), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF), and the project River2Ocean – Socio-ecological and biotechnological solutions for the conservation and valorisation of aquatic biodiversity in the Minho Region, with the reference NORTE-01-0145-FEDER-000068, co-financed by the European Regional Development Fund (ERDF), through Programa Operacional Regional do Norte (NORTE 2020), for supporting this work. Financial support to Arne Nygren from the Norwegian Taxonomy Initiative [http://www.biodiversity.no/Pages/135523] (Cryptic polychaete species in Norwegian waters, knr 49- 13, pnr 70184228), the Swedish Taxonomy Initiative [https://www.artdatabanken.se/en/the-swedish taxonomy-initiative/] (Polychaete species complexes in Swedish waters, dnr 140/07 1.4 and 166/08 1.4), and Kungliga Fysiografiska sällskapet Nilsson-Ehle donationerna [https://www.fysiografen.se/sv/]

Prática de recuperação e dificuldade do item : um estudo normativo e um estudo experimental

Dissertação (mestrado)—Universidade de Brasília, Instituto de Psicologia, Departamento de Processos Psicológicos Básicos, Programa de Pós-Graduação em Ciências do Comportamento, 2019.A prática de recuperação de informações da memória promove a retenção em longo prazo. De fato, recuperar informações por meio de testagem melhora a retenção mais que o estudo repetido dessa mesma informação, um fenômeno conhecido como efeito de prática de recuperação. Uma teoria sugere que testes envolvem maior esforço cognitivo que o reestudo, e que tal esforço adicional explica os benefícios de memória proporcionados pela testagem. Se essa hipótese de esforço de recuperação (HER) estiver correta, então itens de estudo difíceis deveriam se beneficiar mais da prática de recuperação que itens de estudo fáceis. Aqui, testou-se essa predição usando a memorabilidade do item como uma estimativa de sua dificuldade. Primeiro, conduzimos um estudo normativo (Manuscrito 1) para obter estimativas de dificuldade do item. No Estudo 1, os participantes julgaram o grau de familiaridade, concretude, valência e alerta de 80 palavras em português, bem como a wordlikeness (grau de similaridade com palavras em português) de suas 80 palavras suaíli correspondentes; no Estudo 2, os participantes realizaram três ciclos de estudo–teste de associações suaíli–português. Regressões múltiplas mostraram que familiaridade, wordlikeness e a memorabilidade prévia predizem a memorabilidade do item. Os pares de palavras normatizados nesses dois estudos foram então usados em dois experimentos de prática de recuperação (Manuscrito 2). Depois do estudo inicial de items fáceis e difíceis, os participantes repetidamente reestudaram metade dos pares e recuperaram a outra metade. Em ambos os experimentos, nós replicamos o efeito de prática de recuperação e o efeito de dificuldade do item. Mais importante, observou-se (a) um menor efeito de prática de recuperação para itens difíceis (Experimento 1) e, depois de controlar os níveis de recordação na fase de prática, (b) uma tendência (não significativa) em direção a um maior efeito de prática de recuperação para itens difíceis, especialmente para participantes que se beneficiaram da testagem (Experimento 2). Os resultados mistos fornecem somente evidências fracas para a HER, sendo discutidos à luz de teorias alternativas do efeito de prática de recuperação.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).Retrieval practice promotes long-term retention. In fact, retrieving information by testing improves retention more than repeated study of that same information, a phenomenon known as the retrieval practice effect. One account suggests that tests involve greater cognitive effort than restudy, and that such additional effort explains the memory benefits afforded by testing. If this retrieval effort hypothesis (REH) is correct, then difficult study items (which require more retrieval effort) should benefit more from retrieval practice than easy study items (which require less retrieval effort). Here we tested this prediction by using item memorability as an estimate of item difficulty. First, we conducted a normative study (Manuscript 1) to obtain item difficulty estimates. In Study 1, participants judged 80 Portuguese words for familiarity, concreteness, valence, arousal and 80 corresponding Swahili words for wordlikeness (similarity to Portuguese); in Study 2, participants underwent three study–test cycles on Swahili–Portuguese associations. Multiple regressions showed that familiarity, wordlikeness, and previous memorability predicted current item memorability. The word pairs normed in these two studies were then used in two retrieval practice experiments (Manuscript 2). After the initial study of easy and difficult items, participants repeatedly restudied half of the pairs and retrieval practiced the other half. In both experiments, we replicated the retrieval practice effect and the item difficulty effect. More importantly, we also found (a) a smaller retrieval practice effect for difficult items (Experiment 1) and, after controlling for practice-phase recall levels, (b) a (non-significant) trend toward a greater retrieval practice effect for difficult items, particularly for positive testers (Experiment 2). The mixed results provide only weak evidence for the REH and are discussed in relation to alternative accounts of the retrieval practice effect