A visual-display and storage device

Memory and display device uses cathodochromic material to store visual information and fast phosphor to recall information for display and electronic processing. Cathodochromic material changes color when bombarded with electrons, and is restored to its original color when exposed to light of appropiate wavelength

Delay Line as a Chemical Reaction Network

Chemistry as an unconventional computing medium presently lacks a systematic approach to gather, store, and sort data over time. To build more complicated systems in chemistries, the ability to look at data in the past would be a valuable tool to perform complex calculations. In this paper we present the first implementation of a chemical delay line providing information storage in a chemistry that can reliably capture information over an extended period of time. The delay line is capable of parallel operations in a single instruction, multiple data (SIMD) fashion. Using Michaelis-Menten kinetics, we describe the chemical delay line implementation featuring an enzyme acting as a means to reduce copy errors. We also discuss how information is randomly accessible from any element on the delay line. Our work shows how the chemical delay line retains and provides a value from a previous cycle. The system's modularity allows for integration with existing chemical systems. We exemplify the delay line capabilities by integration with a threshold asymmetric signal perceptron to demonstrate how it learns all 14 linearly separable binary functions over a size two sliding window. The delay line has applications in biomedical diagnosis and treatment, such as smart drug delivery.Comment: 9 pages, 11 figures, 6 table

Cathodochromic storage device

A memory and display device has been developed by combing a fast phosphor layer with a cathodochromic layer in a cathode ray tube. Images are stored as patterns of electron beam induced optical density in the cathodo-chromic material. The stored information is recovered by exciting the backing, fast phosphor layer with a constant current electron beam and detecting the emitted radiation which is modulated by absorption in the cathodochromic layer. The storage can be accomplished in one or more TV frames (1/30 sec each). More than 500 TV line resolution and close to 2:1 contrast ratio are possible. The information storage time in a dark environment is approximately 24 hours. A reconstituted (readout) electronic video signal can be generated continuously for times in excess of 10 minutes or periodically for several hours

The mid-domain effect: It’s not just about space

Ecologists and biogeographers have long sought to understand how and why diversity varies across space. Up until the late 20th century, the dominant role of environmental gradients and historical processes in driving geographical species richness patterns went largely undisputed. However, almost 20 years ago, Colwell & Hurtt (1994) proposed a radical reappraisal of ecological gradient theory that called into question decades of empirical and theoretical research. That controversial idea was later termed the ‘the mid-domain effect’: the simple proposition that in the absence of environmental gradients, the random placement of species ranges within a bounded domain will give rise to greatest range overlap, and thus richness, at the center of the domain (Colwell & Lees, 2000) (Fig. 1a). The implication of this line of reasoning is that the conventional null model of equal species richness regardless of latitude, elevation or depth should be replaced by one where richness peaks at some midpoint in geographical space. Our intention here is to draw attention to a neglected, yet important manifestation of the mid-domain effect, namely the application of mid-domain models (also referred to as geometric constraint models) to non-spatial domains. If individual species have ranges that exist not just in geographical space but also in environmental factors, such as temperature, rainfall, pH, productivity or disturbance, shouldn’t we also expect mid-domain richness peaks along non-spatial gradients? A mid-domain model applied to non-spatial gradients predicts the maximum potential richness for every value of an environmental factor. As with spatial mid-domain models, realized richness would probably be less, but the limits to richness are still predicted to be hump-shaped. Indeed, hump-shaped relationships emerge with remarkably high frequency across various non-spatial gradients. For instance, two of ecology’s most fundamental, albeit controversial theories – the productivity–diversity relationship and the intermediate disturbance hypothesis – predict mid-domain peaks in species richness. However, the potential of non-spatial mid-domain models has gone largely ignored

Dépistage des mammites subcliniques chez la brebis laitière

Un suivi bactériologique et cytologique de 709 demi-mamelles de brebis laitières a été réalisé sur les campagnes 1994-1995 et 1996-1997 dans le Rayon de Roquefort et dans les Pyrénées Atlantiques. Les 5426 analyses microbiologiques ont mis en évidence que 60% des prélèvements étaient stériles, les staphylocoques ont représenté 33% des isolements et parmi ceux-ci, 80% étaient des staphylocoques à coagulase négative (SCN). La définition et l'utilisation de 6 critères bactériologiques ont permis de classer les demi-mamelles suivies en « saines », « douteuses » ou « infectées » au vu des résultats d'analyses bactériologiques sur l'ensemble de la campagne laitière considérée. Le statut infectieux des brebis a ensuite été défini à partir des statuts de chacune des demi-mamelles d'un animal. Le statut infectieux a été mis en relation avec les résultats de comptages de cellules somatiques (CCS) afin de proposer un outil opérationnel de dépistage des mammites subcliniques. Cet outil consiste en des règles de décision à 2 seuils prenant en considération tout ou partie des comptages de cellules individuels réalisés durant la lactation. A titre d'exemple, l'une de ces règles propose de considérer comme infectée une brebis présentant 1 ou plusieurs CCS supérieurs à 1 million de cellules par mL. Après validation par confrontation à différentes situations de prévalence des mammites subcliniques, ces règles de décision pourraient être utilisées dans le cadre de programmes de maîtrise des comptages de cellules de troupeau