Leaf Mines: Life in (almost) Two Dimensions

The pigmy moths of the family Nepticulidae are the smallest Lepidoptera. They are also called leaf miners as, in the larval stage, they feed on leaves by excavating tunnels in between the two laminas. Some species are considered pests by gardeners and farmers since they feed on fruit plants or flowers, like roses. It is on a plant of rose that grows on a side of our house that I discovered this seasonal intruder that decorate with long tracks lined with the black strip of their frass, the green leaf of our rose. I did some research and I found the name of the culprit: Stigmella anomalella. A nice name for a small pest! Reading more about this little creature, I discovered that has been found fossils dated 97 millions of year ago, this minuscule insect survived dinosaurs (to bother our roses!) so they deserve all my respect for their resilience! – By the way, the study of traces left by insects is a science and it is called Ichnoentomology [3]. Indeed, the curious sinuous trajectory of dwelling inside the leaf cathed my curiosity and I decided to analyze more in details their mining behavior. There are different websites dedicated to the Nepticulidae and on leaf miners in general [2, 3]. I have also found an interesting old book (1955) on the topics of E.M. Hering titled “Biology of the Leaf Miners” that contains interesting information about these insects [4]. Miner tracks are classified  accordingly to their shapes in the following types: 

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La programmazione in Awk II: Life in a Shell

Il gioco Life fu inventato negli anni ’70 dal prolifico matematico John H. Conway (vedi [5] per la sua biografia) ed è diventato famoso dopo la pubblicazione di Martin Gardner nella sua rubrica di matematica amatoriale sulla rivista Scientific American [1,2]. Il gioco è basato sugli automi cellulari concepiti da Konrad Zuse e Stanislaw M. Ulam all’inizio degli anni ’50, e poi adottati da John von Neumann per il suo studio sugli automi auto-replicanti [2,3]. Un automa cellulare è composto da unità (celle) interagenti disposte in una griglia quadrataIl sistema si evolve in cicli di vita in cui ogni cella cambia stato e nuove celle possono nascere e altre possono sopravvivere o, eventualmente, morire. Lo stato di ogni cella nel ciclo successivo è definito dall’interazione con le celle adiacenti in base a delle regole. L’interazione avviene con i primi vicini di ciascuna cella. Come mostrato nella Figura 1, è possibile utilizzare due tipi di intorni (cerchi) della cella centrale. Il gioco Life usa il tipo di proposto da Moore. 

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Awk Programming II: Life in a Shell

The game of Life was invented in the ’70 by the prolific mathematician John H. Conway (on the 11/4/2020 sadly J.H. Conway passed away at the age of 82 after having contracted the COVID-19, see [5] for his biography). The game becomes popular after Martin Gardner described it in his famous column in the Scientific American magazine [1,2].  The game is based on cellular automata conceived by Konrad Zuse and Stanislaw M. Ulam at beginning of the ’50 and then adopted by John von Neumann for his study on self-replicating automata [2,3]. A cellular automaton is composed of interacting units (cells) arranged in a square grid. The system evolves in life cycles where each cell change status and new cells can be born, and others can survive or eventually die. The status of each cell in the next cycle is defined by the interaction with their neighbor cells according to a given set of rules. The interaction occurs with the first neighbors of each cell. As shown in Figure 1, two type of neighbor’s cells (circles) can be used, the game of Life uses the Moore type neighborhood.

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