Projections of surfaces with a connected fold curve

AbstractLet S be a surface (compact, connected and without boundary) and ƒ: S → R2 a generic smooth mapping. Suppose the apparent contour γ is irreducible (which means the fold curve of ƒ is connected). We give a criterion to decide if the number of singularities in the contour is the least possible or not, and we see that these minimal values for the cusps and double points of γ depend on the the Euler-Poincaré characteristic χ(S) of the surface. In the course of our proof, we illustrate the construction of such “minimal” projections for surfaces of arbitrary genus. All operations involved can be performed by using manifolds immersed in R3

Trial application of pupillometry for a maritime usability study in field conditions

Eye-tracking is a tool employed in usability testing. It is primarily intended as a means for tracking the visual attention patterns of an observer on a continuous basis. Eye-tracking can also capture certain physiological data, such as pupil dilation. Pupil diameter is a validated metric of cognitive workload, meaning the pupil dilates with increasing workload. This research evaluates the fitness, in field conditions, of an eye-tracking based method for accurate measurement of cognitive workload. This implies evaluating the fitness of this tool in changing light conditions such as in coastal navigation. This methodology thus accounts for the effect of light on pupil dilation. This means we are able to account for the effect of only cognitive workload on the pupil dilation even in changing light conditions. This method was applied as a part of an analysis of a navigational exercise involving the navigator and the navigator’s assistant on board a training vessel of the Royal Norwegian Naval Academy. Pupillometry is used alongside egocentric video recordings and Geo-positioning systems (GPS) recordings to allow for multi-faceted evaluation of the activity. Subjective data was recorded as well to evaluate the quality of the eye-tracking data. Subjective data was recorded using NASA-TLX self-report of mental workload, self-report of mental workload (on three levels) using maps and an expert assessment of the mental workload was obtained for the navigational course. The analysis concluded that pupillometry (through eye-trackers) can have a substantial role in the evaluation of field operations and provide a good and objective estimate of the perceived workload. The eye-tracking technology has substantial limitations, for example sometimes strong infra-red sources of light can impede data collection as such with an eye-tracker, meaning the analysis is labour intensive as it relies on the ability of the operator to filter out low quality data and retain the rest

Tipografia parametrica e Developmental Dyslexia

Is a font designed for the purpose of helping people with a diagnosis of DD actually beneficial? Which are the visual variables that may facilitate reading in readers with a diagnosis of DD? We designed a parametric software that allows to generate a huge variety of fonts.The parametric variables allow to changethe appearance of the font without changing the proportions and the main metric dimensions. This allows to isolate the variables and to make the assessment more accurate. The experiments we conducted did not gave any evident and objective result that drive to the adoption of a specific font or variable in order to improve significantly the reading performance. The font which is preferred at a glance does not seem to improve objectively the reading performance

The C. elegans tailless/Tlx homolog nhr-67 regulates a stage-specific program of linker cell migration in male gonadogenesis

Cell migration is a common event during organogenesis, yet little is known about how migration is temporally coordinated with organ development. We are investigating stage-specific programs of cell migration using the linker cell (LC), a migratory cell crucial for male gonadogenesis of C. elegans. During the L3 and L4 larval stages of wild-type males, the LC undergoes changes in its position along the migratory route, in transcriptional regulation of the unc-5 netrin receptor and zmp-1 zinc matrix metalloprotease, and in cell morphology. We have identified the tailless homolog nhr-67 as a cell-autonomous, stage-specific regulator of timing in LC migration programs. In nhr-67-deficient animals, each of the L3 and L4 stage changes is either severely delayed or never occurs, yet LC development before the early L3 stage or after the mid-L4 stage occurs with normal timing. We propose that there is a basal migration program utilized throughout LC migration that is modified by stage-specific regulators such as nhr-67

Tipografia parametrica e Developmental Dyslexia

Is a font designed for the purpose of helping people with a diagnosis of DD actually beneficial? Which are the visual variables that may facilitate reading in readers with diag-nosis of DD?We designed a parametric software that allows to generate a huge variety of fonts.The parametric variables allow to change the appearance of the font without changing the proportions and the main metric dimensions. This allows to isolate the variables and to make the assessment more accurate. The experiments we conducted did not gave any evident and objective result that drive to the adoption of a specific font or variable in order to improve significantly the reading per-formance. The font which is preferred at a glance does not seem to improve objectively the reading performance

The Torso signaling pathway modulates a dual transcriptional switch to regulate tailless expression

The Torso (Tor) signaling pathway activates tailless (tll) expression by relieving tll repression. None of the repressors identified so far, such as Capicuo, Groucho and Tramtrack69 (Ttk69), bind to the tor response element (tor-RE) or fully elucidate tll repression. In this study, an expanded tll expression pattern was shown in embryos with reduced heat shock factor (hsf) and Trithorax-like (Trl) activities. The GAGA factor, GAF encoded by Trl, bound weakly to the tor-RE, and this binding was enhanced by both Hsf and Ttk69. A similar extent of expansion of tll expression was observed in embryos with simultaneous knockdown of hsf, Trl and ttk69 activities, and in embryos with constitutively active Tor. Hsf is a substrate of mitogen-activated protein kinase and S378 is the major phosphorylation site. Phosphorylation converts Hsf from a repressor to an activator that works with GAF to activate tll expression. In conclusion, the GAF/Hsf/Ttk69 complex binding to the tor-RE remodels local chromatin structure to repress tll expression and the Tor signaling pathway activate tll expression by modulating a dual transcriptional switch