Use of acrylic sheet molds for elastomeric products

Molds constructed of acrylic sheet are more easily machined than metal, are transparent to ensure complete filling during injection, and have smooth surfaces free of contamination. Technique eliminates flashing on molded parts and mold release agents

The PVLAS experiment: measuring vacuum magnetic birefringence and dichroism with a birefringent Fabry-Perot cavity

Vacuum magnetic birefringence was predicted long time ago and is still lacking a direct experimental confirmation. Several experimental efforts are striving to reach this goal, and the sequence of results promises a success in the next few years. This measurement generally is accompanied by the search for hypothetical light particles that couple to two photons. The PVLAS experiment employs a sensitive polarimeter based on a high finesse Fabry-Perot cavity. In this paper we report on the latest experimental results of this experiment. The data are analysed taking into account the intrinsic birefringence of the dielectric mirrors of the cavity. Besides the limit on the vacuum magnetic birefringence, the measurements also allow the model-independent exclusion of new regions in the parameter space of axion-like and milli-charged particles. In particular, these last limits hold also for all types of neutrinos, resulting in a laboratory limit on their charge

Measurements of vacuum magnetic birefringence using permanent dipole magnets: the PVLAS experiment

The PVLAS collaboration is presently assembling a new apparatus (at the INFN section of Ferrara, Italy) to detect vacuum magnetic birefringence (VMB). VMB is related to the structure of the QED vacuum and is predicted by the Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by measuring the ellipticity acquired by a linearly polarised light beam propagating through a strong magnetic field. Using the very same optical technique it is also possible to search for hypothetical low-mass particles interacting with two photons, such as axion-like (ALP) or millicharged particles (MCP). Here we report results of a scaled-down test setup and describe the new PVLAS apparatus. This latter one is in construction and is based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity ($>4\times 10^5$) and two 0.8 m long 2.5 T rotating permanent dipole magnets. Measurements with the test setup have improved by a factor 2 the previous upper bound on the parameter $A_e$, which determines the strength of the nonlinear terms in the QED Lagrangian: $A_e^{\rm (PVLAS)} < 3.3 \times 10^{-21}$ T$^{-2}$ 95% c.l. Furthermore, new laboratory limits have been put on the inverse coupling constant of ALPs to two photons and confirmation of previous limits on the fractional charge of millicharged particles is given

New PVLAS model independent limit for the axion coupling to γγ\gamma\gamma for axion masses above 1meV

During 2014 the PVLAS experiment has started data taking with a new apparatus installed at the INFN Section of Ferrara, Italy. The main target of the experiment is the observation of magnetic birefringence of vacuum. According to QED, the ellipticity generated by the magnetic birefringence of vacuum in the experimental apparatus is expected to be $\psi^{\rm(QED)} \approx 5\times10^{-11}$. No ellipticity signal is present so far with a noise floor $\psi^{\rm(noise)} \approx 2.5\times10^{-9}$ after 210 hours of data taking. The resulting ellipticity limit provides the best model independent upper limit on the coupling of axions to $\gamma\gamma$ for axion masses above $10^{-3}$eV

Measurement of the Cotton Mouton effect of water vapour

In this paper we report on a measurement of the Cotton Mouton effect of water vapour. Measurement performed at room temperature ($T=301$ K) with a wavelength of 1064 nm gave the value $\Delta n_u = (6.67 \pm 0.45) \cdot 10^{-15}$ for the unit magnetic birefringence (1 T magnetic field and atmospheric pressure)

First results from the new PVLAS apparatus: a new limit on vacuum magnetic birefringence

Several groups are carrying out experiments to observe and measure vacuum magnetic birefringence, predicted by Quantum Electrodynamics (QED). We have started running the new PVLAS apparatus installed in Ferrara, Italy, and have measured a noise floor value for the unitary field magnetic birefringence of vacuum $\Delta n_u^{\rm (vac)}= (4\pm 20) \times 10^{-23}$ T$^{-2}$ (the error represents a 1$\sigma$ deviation). This measurement is compatible with zero and hence represents a new limit on vacuum magnetic birefringence deriving from non linear electrodynamics. This result reduces to a factor 50 the gap to be overcome to measure for the first time the value of $\Delta n_u^{\rm (vac,QED)}$ predicted by QED: $\Delta n_u^{\rm (vac,QED)}= 4\times 10^{-24}$ ~T$^{-2}$. These birefringence measurements also yield improved model-independent bounds on the coupling constant of axion-like particles to two photons, for masses greater than 1 meV, along with a factor two improvement of the fractional charge limit on millicharged particles (fermions and scalars), including neutrinos

Tourist creative processes and experiences in the European Cultural Itinerary ‘The Phoenicians’ Route’

Cultural itineraries represent a favourable context for the development of creative processes and experiences. This paper examines the creative activities and projects of a European Cultural Itinerary, The Phoenicians’ Route. The aim was to explore the creative features related to the production and development of the cultural-tourist offer, through a survey of participants in a pilot project, and on a network of local partners that co-operate in running the itinerary. The results of this research provide a rating of the total potential of itinerary itself, contributing to its definition as a ‘creative system’

No Difference in Stress Level Based on Physical Activity During the COVID-19 Pandemic Among Parents of School-Aged Children

Stress levels among children and parents have been heightened during the COVID-19 pandemic, especially with related changes in school structure. Regular physical activity (PA) represents a way to decrease stress levels and improve overall mood. Thus, regular PA is even more important during this period of prolonged stress as the pandemic continues to affect communities. PURPOSE: The purpose of this study was to examine differences in stress levels among parents of school-aged children during the COVID-19 pandemic based upon physical activity patterns. METHODS: Parents (n = 115, 91% female, 91% White) of school-aged children in the United States participated in surveys regarding their stress levels and physical activity. Stress levels were determined by the Perceived Stress Scale and dichotomized into Low Stress or Moderate/High Stress. To determine level of physical activity, participants also completed the Recreational and Sedentary portions of the WHO\u27s Global Physical Activity Questionnaire (7 questions). They were then dichotomized into “met” or “did not meet” World Health Organization’s recommendations for weekly physical activity (150 minutes moderate PA (MPA), 70 minutes of vigorous PA (VPA), or 600 MET*minutes). Perceived stress levels were analyzed using a chi-square test to determine any differences between the two groups based upon each WHO recommendation for physical activity (MPA, VPA, MET*minutes). RESULTS: A total of 47% of parents perceived themselves as having low stress while 53% reported moderate/high stress. A majority of parents did not meet WHO PA recommendations for weekly MPA (63%) nor VPA (64%) but did meet recommendations for weekly MET*min (59%). All chi-square tests were non-significant (MPA: Χ2 = .246, df = 1, p = .620; VPA: Χ2 = 3.422, df = 1, p = .064; MET*min: Χ2 = 1.361, df = 1, p = .243). CONCLUSION: The present study demonstrates that there was no significant difference in perceived stress levels based upon physical activity among parents of school-aged children during the COVID-19 pandemic, regardless of intensity of the physical activity. Even with the known positive benefits of PA to decrease stress, PA was not significantly associated with reduced stress levels among parents of school-aged youth. This finding could reflect stress exceeding normal levels due to the novel and unknown nature of the pandemic. It is also possible that PA did have a positive impact on stress levels but was too small to significantly counteract the abnormal increase in perceived stress. However, PA is still important for adults, including parents of school-aged youth, during the COVID-19 pandemic due to the numerous other health benefits it can provide beyond reducing stress levels

Open and / or laparoscopic surgical treatment of liver hydatic cysts

Hydatid disease is a severe parasitic disease with a widely ranging distribution. In the human being the liver is the most frequent organ affected. 1 The treatment should be individualized to the morphology, size, number and location of the cysts, that is why a variety of surgical operations have been advocated from complete resection like total pericystectomy or partial hepatectomy to laparoscopy to a minimally invasive procedures like percutaneous aspiration of cysts to conservative drug therapy. 3-4 This study compares laparoscopic versus open management of the hydatid cyst of liver the surgical approach to liver echinococcosis is still a controversial issue and shows our results of surgical treatment of liver hydatid cysts during a 3-years period