Suppressors of selection

Inspired by recent works on evolutionary graph theory, an area of growing interest in mathematical and computational biology, we present the first known examples of undirected structures acting as suppressors of selection for any fitness value $r > 1$. This means that the average fixation probability of an advantageous mutant or invader individual placed at some node is strictly less than that of this individual placed in a well-mixed population. This leads the way to study more robust structures less prone to invasion, contrary to what happens with the amplifiers of selection where the fixation probability is increased on average for advantageous invader individuals. A few families of amplifiers are known, although some effort was required to prove it. Here, we use computer aided techniques to find an exact analytical expression of the fixation probability for some graphs of small order (equal to $6$, $8$ and $10$) proving that selection is effectively reduced for $r > 1$. Some numerical experiments using Monte Carlo methods are also performed for larger graphs.Comment: New title, improved presentation, and further examples. Supporting Information is also include

[Review of] Library of Congress. The Card Catalog: Books, Cards, and Literary Treasures

Review of the book "The Card Catalog: Books, Cards, and Literary Treasures" published by the Library of Congres

Presencia de Mirosphinctes (Ammonitina, Perisphinctacea) en la zona Subbética (Cordilleras Béticas, España)

Todavia no había sido citado en las Cordilleras béticas (Zona Subbética) el género Mirosphinctes; recientemente ha sido encontrado en la zona de bimammatum de Sierra Gorda (Loja, España) un ejemplar clasificado como nueva especie (Mirosphinctes myczynskii nov. sp.) similar a la fauna procedente de la parte occidental de Cuba

Bibliotecas públicas em tempos difíceis

The study of everyday-life during World War II showed how attendance and valuation of public libraries may considerably increase during “Hard Times”. Some of the reasons are expected – free reading – and some other are occasionally surprising – shelter under adverse atmospheric conditions, appreciated levels of comfort such as lighting, desired (and recently-lost?) social interaction. It should be noted that, in some European and North-American countries, there were neighbourhood libraries located throughout the big city, acting as estimated proximity services. Being aware of this reality helps us understand why cultural and recreational services, and nowadays Web services too, are not less, but even more important in times of crisis. In Portugal, and in the last decade, public libraries have been steadily degraded through the reduction of adequately qualified personnel and through a generalised lack of the updating of collections, along with other cuts. Certain technological options do not appear to have been made according to the needs of readers but following non-transparent investment choices away of public scrutiny. If Wi-Fi is quite widespread now, ebooks have not entered public libraries yet. However, we may question: What shelters do we want in our city to read in, and how do we want to read? “Secludedly” alone, in a community without propinquity? Do we tolerate intrusions while reading in public? Who pushes those technological choices? And above all: if we are deprived of these spaces or of these services, who will fill this void? Will they still be "built for us"?O estudo de quotidianos da 2ª Grande Guerra mostrou como a afluência e valorização das bibliotecas públicas podem aumentar consideravelmente em Tempos Difíceis. Por razões expectáveis – leitura gratuita – e por outras talvez mais surpreendentes – abrigo em condições atmosféricas adversas, iluminação, níveis de conforto apreciados, interação social desejada (e recém-perdida?). Note-se que, em alguns países da Europa e no Norte da América, havia bibliotecas de bairro distribuídas pela cidade grande, atuando como estimados serviços de proximidade. Conhecer essa realidade ajuda a compreender porque serviços culturais, de recreação (e hoje em dia também serviços Web) são, não menos, mas ainda mais importantes em tempos de crise. Em Portugal, na última década, as bibliotecas públicas têm sido paulatinamente degradadas pela redução no pessoal com qualificação adequada e por uma generalizante falta de atualização das coleções, a par doutros cortes. Certas opções tecnológicas não parecem ter sido feitas de acordo com necessidades de leitores mas por opções de investimento não transparentes para o público. Se o Wi-Fi está bastante generalizado, os ebooks não chegaram ainda às bibliotecas públicas. Entretanto podemos questionar: Que abrigos queremos na cidade e como queremos ler? Esconsamente sós, em comunidade sem propinquidade? Toleramos intrusões na leitura pública? Quem empurra estas opções tecnológicas? E acima de tudo: se ficarmos sem estes espaços ou serviços, quem irá preencher o vazio? Serão ainda “construídos para nós”