Measuring Propagation Speed of Coulomb Fields

The problem of gravity propagation has been subject of discussion for quite a long time: Newton, Laplace and, in relatively more modern times, Eddington pointed out that, if gravity propagated with finite velocity, planets motion around the sun would become unstable due to a torque originating from time lag of the gravitational interactions. Such an odd behavior can be found also in electromagnetism, when one computes the propagation of the electric fields generated by a set of uniformly moving charges. As a matter of fact the Li\'enard-Weichert retarded potential leads to a formula indistinguishable from the one obtained assuming that the electric field propagates with infinite velocity. Feyman explanation for this apparent paradox was based on the fact that uniform motions last indefinitely. To verify such an explanation, we performed an experiment to measure the time/space evolution of the electric field generated by an uniformely moving electron beam. The results we obtain on such a finite lifetime kinematical state seem compatible with an electric field rigidly carried by the beam itself.Comment: 23 pages, 15 figure

The Impact of Flag Desecration on Social Justice Movements: The Case of Occupy SLU

The unrest in Ferguson, Missouri brought about many points of contention that evolved into a collective, dualistic mindset: an “us-versus-them mentality” that set community members at odds with each other. A notable instance of divisiveness was the desecration of the American flag by some demonstrators, the merit of which is hotly debated. Some see the desecration of the flag as a powerful means of protest, a literal destruction of a perceived symbol of institutional oppression. Others see it as the ultimate insult to our nation and our nation’s service members who volunteer to uphold the very foundations that protect demonstrators. In the months following the unrest, the demonstrations made their way onto the campus of Saint Louis University, a Jesuit institution in St. Louis, Missouri, organizing the Occupy SLU movement. In the aftermath of this movement, researchers asked students to share their experiences. This research has its origins in that study, focused upon the student experiences on and near campus. This paper provides a brief overview of the historical foundations of flag desecration and evaluates the perceptions of students concerning the use of flag desecration as a tactic during the Occupy SLU movement

Alternative somatic cell count traits exploitable in genetic selection for mastitis resistance in Italian Holsteins

The aim of the present study was to characterize alternative somatic cell count (SCC) traits that could be exploited in genetic selection for mastitis resistance. Data were from 66,407 first-parity Holsteins in 404 herds. Novel SCC traits included average somatic cell score (SCS, log-transformation of SCC) in early lactation (SCS_150), standard deviation of SCS of the entire lactation (SCS_SD), the presence of at least one test-day (TD) SCC >400,000 cells/mL in the lactation, and the ratio of number of TD SCC >400,000 cells/mL to total number of TD in the lactation. Novel traits and lactation-mean SCS (SCS_LM) were analyzed using linear mixed or logistic regression models, including month of calving, year of calving, number of TD, and milk yield as fixed effects, and herd and residual as random terms. A multitrait linear animal model was applied to a random subset of 152 herds (n = 22,695 cows) to assess heritability of and genetic correlations between SCC traits. Alternative SCC traits were affected by the environmental factors included in the model; in particular, results suggested a seasonal effect and a tendency toward an improvement of the udder health status in the last years. Association was also found between novel SCC traits and milk production. Alternative SCC traits exhibited coefficients of additive genetic variation that were similar to or larger than that of traditional SCS_LM. Heritability of novel SCC traits was smaller than heritability of SCS_LM (0.126 \ub1 0.014), ranging from 0.044 \ub1 0.008 (SCS_SD) to 0.087 \ub1 0.010 (SCS_150). Genetic correlations between SCC traits ranged from 0.217 \ub1 0.096 (SCS_150 and SCS_SD) to 0.969 \ub1 0.010 (SCS_LM and SCS_150). Alternative SCC traits exhibited additive genetic variation that is potentially exploitable in breeding programs of Italian Holstein population to improve resistance to mastitis

Some closure operations in Zariski-Riemann spaces of valuation domains: a survey

In this survey we present several results concerning various topologies that were introduced in recent years on spaces of valuation domains

Beam test of scintillation tiles with MPPC readout

This paper describes measurements made using counters composed of a small (3 by 3 by 0.5 cm3) scintillation tile coupled to a Multi-Photon Pixel Counter (MPPC) produced by Hamamatsu and exposed to an electron beam at the Beam Test Facility in Frascati. We show our first results for charge spectra and efficiency, and a very preliminary measurement of device linearity