Conicoid Mirrors

The first order equation relating object and image location for a mirror of arbitrary conic-sectional shape is derived. It is also shown that the parabolic reflecting surface is the only one free of aberration and only in the limiting case of distant sources.Comment: 9 page

Two-ply channels for faster wicking in paper-based microfluidic devices

This article describes the development of porous two-ply channels for paper-based microfluidic devices that wick fluids significantly faster than conventional, porous, single-ply channels. The two-ply channels were made by stacking two single-ply channels on top of each other and were fabricated entirely out of paper, wax and toner using two commercially available printers, a convection oven and a thermal laminator. The wicking in paper-based channels was studied and modeled using a modified Lucas–Washburn equation to account for the effect of evaporation, and a paper-based titration device incorporating two-ply channels was demonstrated

Transversality of Electromagnetic Waves in the Calculus-Based Introductory Physics Course

Introductory calculus-based physics textbooks state that electromagnetic waves are transverse and list many of their properties, but most such textbooks do not bring forth arguments why this is so. Both physical and theoretical arguments are at a level appropriate for students of courses based on such books, and could be readily used by instructors of such courses. Here, we discuss two physical arguments (based on polarization experiments and on lack of monopole electromagnetic radiation), and the full argument for the transversality of (plane) electromagnetic waves based on the integral Maxwell equations. We also show, at a level appropriate for the introductory course, why the electric and magnetic fields in a wave are in phase and the relation of their magnitudes.Comment: 10 pages, 6 figure

Analysis of 19 Minerals and Cortisol in Red Deer Hair in Two Different Areas of the Stelvio National Park: A Preliminary Study

The aim of the study was to perform an investigation on the concentration of 19 minerals and cortisol in red deer (Cervuselaphus) hair, a matrix that is easy to collect with non-invasive and painless sampling, able to represent an integrative values of long-term substance concentrations, and able to give useful information, also when performed on dead animals, given its extreme stability over time. In the study thirty-five animals were included, coming from two different sides of a valley in the Stelvio National Park, where official water analysis had pointed out elevated concentrations of As in one of the two orographic sides. Hair cortisol concentrations were measured using a RIA(Radio Immuno Assay), while minerals were detected using ICP-MS (Inductively Coupled Plasma- Mass Spectrometry). Results showed a negative relationship between cortisol and some mineral concentrations (Li, Co, As, Cd, Cr and Tl) and significant differences in some mineral concentrations between park areas (Al, Co, Cu, Cd and Ni). As, Cr and cortisol differences approached statistical significance. This preliminary study represents a step forward in the study of wildlife allostatic load and a valid method for applications in wildlife management programs, in environmental studies and in public health programs

Ultrafast time-resolved spectroscopy of 1D metal-dielectric photonic crystals

We study the all-optical switching behavior of one-dimensional metal-dielectric photonic crystals due to the nonlinearity of the free metal electrons. A polychromatic pump-probe setup is used to determine the wavelength and pump intensity dependence of the ultrafast transmission suppression as well as the dynamics of the process on a subpicosecond timescale. We find ultrafast (sub-picosecond) as well as a slow (millisecond) behavior. We present a model of the ultrafast dynamics and nonlinear response which can fit the measured data well and allows us to separate the thermal and the electronic response of the system.Comment: 7 pages, 5 figure

The case report of a 31-year-old man with giant cell myocarditis successfully treated with combined immunosuppression and veno-arterial extracorporeal membrane oxygenation for 21 days

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Il rischio di saturnismo negli uccelli necrofagi in relazione alle attuali modalità di caccia degli ungulati

Summary Wildlife may be exposed to lead contamination as a consequence of hunting activities. Waterfowls and grouses may directly assume lead from the ground (primary assumption), while in raptors lead intoxication may be due to the ingestion of preys with elevated lead concentrations in their tissues (secondary assumption). Recent studies demonstrated that viscera of shot ungulates are quite often directly contaminated with lead due to bullet fragmentation after the shot. If released on the ground, viscera represent a threat for scavenger species. In Europe, saturnism in birds of prey has been quite rarely described and some reports are available for large raptors as griffon vulture Gyps fulvus, golden eagle Aquila chrysaetos and bearded vulture Gypaetus barbatus. In the Alps this problem affects the abundant population of golden eagle and the recently re-introduced population of bearded vulture that is still considered as vulnerable. For the bearded vulture two cases of lead intoxication have already been described in dispersing juveniles. The most viable nucleus of bearded vultures is distributed in the central Alps, between Italy and Switzerland and is characterized by the highest reproductive rates. Hunting management of ungulates is here commonly performed with lead ammunition. The practice of leaving on the ground the ungulate viscera after the shot is still frequent. Hunting season partially overlaps with the most limiting season, in terms of food availability, for birds. The extraordinary conservation value of this bearded vulture population led the Stelvio National Park and the Sondrio Province to implement a study for monitoring the potential risk of lead intoxication for raptors tied to the practice of ungulate viscera deposition after the shot. The viscera of 153 ungulates shot in the Sondrio Province during hunting season 2009-2010 have been collected and examined to detect and quantify lead presence. Information regarding the hunted animal, the type of ammunition, the condition and the outcome of the shot have been collected as ancillary data. Lead fragments in the samples have been investigated through CAT (computed axial tomography) and digital radiography and subsequently manually collected. Overall, in 62.1% of samples lead fragments have been detected. Preliminary results refer to a partial sample of 147 viscera of roe deer, red deer, chamois, wild boar and mouflon. Higher frequencies have been recorded in roe deer (77.7%), chamois (69.6%) while lower in red deer (50%). The highest frequencies of lead in viscera have been detected in ungulates shot in the thorax or in the thigh and hind parts. These first preliminary outcomes confirm the high risk of lead intoxication for large raptors in areas where ungulates are commonly hunted and demonstrate the need of more sustainable hunting practices as the substitution of lead ammunition with non-toxic bullets or concealing under the ground the viscera of the shot ungulates

Constructing Fresnel reflection coefficients by ruler and compass

A simple and intuitive geometical method to analyze Fresnel formulas is presented. It applies to transparent media and is valid for perpendicular and parallel polarizations. The approach gives a graphical characterization particularly simple of the critical and Brewster angles. It also provides an interpretation of the relation between the reflection coefficients for both basic polarizations as a symmetry in the plane