Major Tourists’ Security Concerns in France at the Present Stage of Travel Business Development

France is the first most popular tourist destination in the international tourism. The article gives another look on France: homeless illegal immigrants, raids on synagogues, inappropriate conduct of migrants from North Africa. Besides, the article gives some recommendations on less troubled areas of France

The reflection of very cold neutrons from diamond powder nanoparticles

We study possibility of efficient reflection of very cold neutrons (VCN) from powders of nanoparticles. In particular, we measured the scattering of VCN at a powder of diamond nanoparticles as a function of powder sample thickness, neutron velocity and scattering angle. We observed extremely intense scattering of VCN even off thin powder samples. This agrees qualitatively with the model of independent nanoparticles at rest. We show that this intense scattering would allow us to use nanoparticle powders very efficiently as the very first reflectors for neutrons with energies within a complete VCN range up to $10^{-4}$ eV

The Evaluation of V_{ud}, Experiment and Theory

The value of the V_{ud} matrix element of the Cabibbo-Kobayashi-Maskawa (CKM) matrix can be derived from nuclear superallowed beta decays, neutron decay, and pion beta decay. We survey current world data for all three. Today, the most precise value of V_{ud} comes from the nuclear decays; however, the precision is limited not by experimental error but by the estimated uncertainty in theoretical corrections. Experimental uncertainty does limit the neutron-decay result, which, though statistically consistent with the nuclear result, is approximately a factor of three poorer in precision. The value obtained for $V_{ud}$ leads to a result that differs at the 98% confidence level from the unitarity condition for the CKM matrix. We examine the reliability of the small calculated corrections that have been applied to the data, and assess the likelihood of even higher quality nuclear data becoming available to confirm or deny the discrepancy. Some of the required experiments depend upon the availability of intense radioactive beams. Others are possible today.Comment: 21 pages, 1 figure, LaTe

ВЛИЯНИЕ РАЗЛИЧНЫХ ФАКТОРОВ НА ПРИНЯТИЕ РЕШЕНИЯ О ПРИГОДНОСТИ ДОНОРСКОЙ ПОДЖЕЛУДОЧНОЙ ЖЕЛЕЗЫ К ТРАНСПЛАНТАЦИИ РЕЦИПИЕНТУ

AAim. To identify factors influencing upon decision on pancreas allograft suitability for transplant and their clinical significance. Materials and methods. We reviewed 95 multiorgan donors under the age of 45, who were considered as pancreas donor between January 2010 and December 2013. 28 pancreata were procured (Group I), 67 pancreata were refused (Group II). Demographic, clinical and laboratory data, anatomical hepatopancreatoduodenal varieties were taken into account. Results. We found that only three factors have an effect on pancreas allograft refusal probability. According to our data, non-transplantation of the liver from the same donor increases the pancreas graft refusal in 4 times. Elevated donor’s sodium and urea blood levels also increase the probability of donor pancreas denial for transplantation. For example, the probability of pancreas graft refusal from the donor with sodium level 145 mmol/l and urea level 6.0 mol/l is only 32%. As compared to the donor with sodium level 160 mmol/l and urea 12.0 mol/l where probability reaches 85%. Other factors: demographic, laboratory, clinical indicators, gepatopancreatoduodenal blood supply variations were not predictive for the procurement decision. Conclusion. Main predictors of pancreas allograft refusal to be taken into account, appropriate correction of donor metabolic disturbances and sufficient experience of the surgeon performing the procurement can increase the availability of pancreas transplantation.  Цель исследования: выявить закономерности, критерии и факторы, влияющие на решение об изъятии поджелудочной железы для трансплантации реципиенту и их клиническую значимость. Материалы и методы. Проанализированы донорские карты 95 мультиорганных доноров в возрасте до 45 лет, которые рассматривались как возможные доноры поджелудочной железы, в период с 1 января 2010 г. по 31 декабря 2013 г. Поджелудочная железа была изъята в составе других органов у 28 доноров (I группа), отказ от изъятия поджелудочной железы при изъятии других органов зафиксирован у 67 доноров (II группа). Учитывались возраст, рост, вес, половая и расовая принадлежности, клинические, лабораторные данные, анатомические  особенности  гепатопанкреатодуоденальной  зоны  доноров.  Результаты.  Установлено, что на вероятность изъятия поджелудочной железы влияют 3 фактора. Согласно полученным данным, отказ от изъятия печени увеличивает вероятность отказа от поджелудочной железы в 4 раза. Повышенные уровни натрия и мочевины в крови донора также повышают вероятность признания поджелудочной железы не пригодной для трансплантации. Например, вероятность отказа от поджелудочной железы у донора с уровнем Nа 145 ммоль/л, мочевиной 6,0 моль/л составляет лишь 32%. А у донора с уровнем Nа 160 ммоль/л, мочевиной 12,0 моль/л намного выше – 85%. Другие факторы – лабораторные, клинические показатели, вариантное кровоснабжение гепатопанкреатодуоденальной зоны – не являлись предикторами принятия решения об изъятии. Заключение. Учет при принятии решения качества донорской поджелудочной железы, своевременная коррекция метаболических нарушений у донора, достаточный опыт хирурга, выполняющего эксплантацию, могут увеличить доступность трансплантации поджелудочной железы

Magnetic trapping of ultracold neutrons

Three-dimensional magnetic confinement of neutrons is reported. Neutrons are loaded into an Ioffe-type superconducting magnetic trap through inelastic scattering of cold neutrons with 4He. Scattered neutrons with sufficiently low energy and in the appropriate spin state are confined by the magnetic field until they decay. The electron resulting from neutron decay produces scintillations in the liquid helium bath that results in a pulse of extreme ultraviolet light. This light is frequency downconverted to the visible and detected. Results are presented in which 500 +/- 155 neutrons are magnetically trapped in each loading cycle, consistent with theoretical predictions. The lifetime of the observed signal, 660 s +290/-170 s, is consistent with the neutron beta-decay lifetime.Comment: 17 pages, 18 figures, accepted for publication in Physical Review

Options for the Neutron Lifetime Measurements in Traps

Different geometries for the neutron lifetime measurements by the method of ultracold neutron storage in material traps and additional possibilities for the neutron storage in the magnetic storage ring are considered.Comment: 21 p., 11 figure

More about neutron - mirror neutron oscillation

It was pointed out recently that oscillation of the neutron $n$ into mirror neutron $n'$, a sterile twin of the neutron with exactly the same mass, could be a very fast process with the the baryon number violation, even faster than the neutron decay itself. This process is sensitive to the magnetic fields and it could be observed by comparing the neutron lose rates in the UCN storage chambers for different magnetic backgrounds. We calculate the probability of $n-n'$ oscillation in the case when a mirror magnetic field $\vec{B}'$ is non-zero and show that in this case it can be suppressed or resonantly enhanced by applying the ordinary magnetic field $\vec{B}$, depending on its strength and on its orientation with respect to $\vec{B}'$. The recent experimental data, under this hypothesis, still allow the $n-n'$ oscillation time order 1 s or even smaller. Moreover, they indicate that the neutron losses are sensitive to the orientation of the magnetic field. %at about $3\sigma$ level. If these hints will be confirmed in the future experiments, this would point to the presence of the mirror magnetic field on the Earth of the order of 0.1 G, or some equivalent spin-dependent force of the other origin that makes a difference between the neutron and mirror neutron states.Comment: 10 page

The neutron and its role in cosmology and particle physics

Experiments with cold and ultracold neutrons have reached a level of precision such that problems far beyond the scale of the present Standard Model of particle physics become accessible to experimental investigation. Due to the close links between particle physics and cosmology, these studies also permit a deep look into the very first instances of our universe. First addressed in this article, both in theory and experiment, is the problem of baryogenesis ... The question how baryogenesis could have happened is open to experimental tests, and it turns out that this problem can be curbed by the very stringent limits on an electric dipole moment of the neutron, a quantity that also has deep implications for particle physics. Then we discuss the recent spectacular observation of neutron quantization in the earth's gravitational field and of resonance transitions between such gravitational energy states. These measurements, together with new evaluations of neutron scattering data, set new constraints on deviations from Newton's gravitational law at the picometer scale. Such deviations are predicted in modern theories with extra-dimensions that propose unification of the Planck scale with the scale of the Standard Model ... Another main topic is the weak-interaction parameters in various fields of physics and astrophysics that must all be derived from measured neutron decay data. Up to now, about 10 different neutron decay observables have been measured, much more than needed in the electroweak Standard Model. This allows various precise tests for new physics beyond the Standard Model, competing with or surpassing similar tests at high-energy. The review ends with a discussion of neutron and nuclear data required in the synthesis of the elements during the "first three minutes" and later on in stellar nucleosynthesis.Comment: 91 pages, 30 figures, accepted by Reviews of Modern Physic