Magnetic interactions in EuTe epitaxial layers and EuTe/PbTe superlattices

The magnetic properties of antiferromagnetic (AFM) EuTe epitaxial layers and short period EuTe/PbTe superlattices (SLs), grown by molecular beam epitaxy on (111) BaF$_2$ substrates, were studied by magnetization and neutron diffraction measurements. Considerable changes of the N\'eel temperature as a function of the EuTe layer thickness as well as of the strain state were found. A mean field model, taking into account the variation of the exchange constants with the strain-induced lattice distortions, and the nearest neighbor environment of a Eu atoms, was developed to explain the observed $T_{\text N}$ changes in wide range of samples. Pronounced interlayer magnetic correlations have been revealed by neutron diffraction in EuTe/PbTe SLs with PbTe spacer thickness up to 60 \AA. The observed diffraction spectra were analyzed, in a kinematical approximation, assuming partial interlayer correlations characterized by an appropriate correlation parameter. The formation of interlayer correlations between the AFM EuTe layers across the nonmagnetic PbTe spacer was explained within a framework of a tight-binding model. In this model, the interlayer coupling stems from the dependence of the total electronic energy of the EuTe/PbTe SL on the spin configurations in adjacent EuTe layers. The influence of the EuTe and PbTe layer thickness fluctuations, inherent in the epitaxial growth process, on magnetic properties and interlayer coupling is discussed.Comment: 17 pages, 19 figures, accepted to PR

How does gender influence the recognition of cardiovascular risk and adherence to self-care recommendations? : a study in polish primary care

Background: Studies have shown a correlation between gender and an ability to change lifestyle to reduce the risk of disease. However, the results of these studies are ambiguous, especially where a healthy lifestyle is concerned. Additionally, health behaviors are strongly modified by culture and the environment. Psychological factors also substantially affect engagement with disease-related lifestyle interventions. This study aimed to examine whether there are differences between men and women in the frequency of health care behavior for the purpose of reducing cardiovascular risk (CVR), as well as cognitive appraisal of this type of risk. We also aimed to identify the psychological predictors of engaging in recommended behavior for reducing the risk of cardiovascular disease after providing information about this risk in men and women. Methods: A total of 134 consecutive eligible patients in a family practice entered a longitudinal study. At initial consultation, the individual’s CVR and associated health burden was examined, and preventive measures were recommended by the physician. Self-care behavior, cognitive appraisal of risk, and coping styles were then assessed using psychological questionnaires. Six months after the initial data collection, the frequency of subjects’ self-care behavior was examined. Results: We found an increase in health care behavior after providing information regarding the rate of CVR in both sexes; this increase was greater for women than for men. Women followed self-care guidelines more often than men, particularly for preventive measures and dietary advice. Women were more inclined to recognize their CVR as a challenge. Coping style, cognitive appraisal, age, level of health behaviors at baseline and CVR values accounted for 48% of the variance in adherence to self-care guidelines in women and it was 52% in men. In women, total risk of CVD values were most important, while in men, cognitive appraisal of harm/loss was most important. Conclusions: Different predictors of acquisition of health behavior are encountered in men and women. Our results suggest that gender-adjusted motivation models influencing the recognition process need to be considered to optimize compliance in patients with CVR

Hardware Accelerated Simulation of Crest Factor Reduction Block for Mobile Telecommunications

This paper reports results of the hardware accelerated simulations of the crest factor reduction (CFR) block which is a common element of the radio signal processing path in base stations for mobile telecommunications. Presented approach increases productivity of radio system architects by shortening the time of model architecture evaluation. This enables unprecedented scale of CFR parameter optimization which requires thousands of simulation runs. We use FPGA device and Xilinx System Generator for DSP technology in order to model CFR block in MATLAB/Simulink environment, implement the accelerator and use it for mixed hardware-software simulation. Reported approach reduces simulation time by 70%, provides straight forward use of fixed-point arithmetic and lowers power consumption by 73% at the cost of constant and relatively low overhead on model development

Hardware Accelerated Simulation of Crest Factor Reduction Block for Mobile Telecommunications

This paper reports results of the hardware accelerated simulations of the crest factor reduction (CFR) block which is a common element of the radio signal processing path in base stations for mobile telecommunications. Presented approach increases productivity of radio system architects by shortening the time of model architecture evaluation. This enables unprecedented scale of CFR parameter optimization which requires thousands of simulation runs. We use FPGA device and Xilinx System Generator for DSP technology in order to model CFR block in MATLAB/Simulink environment, implement the accelerator and use it for mixed hardware-software simulation. Reported approach reduces simulation time by 70%, provides straight forward use of fixed-point arithmetic and lowers power consumption by 73% at the cost of constant and relatively low overhead on model development

The visualization of the traces of the blocked wheels and the change of the breaking distance at various levels of humidity of the asphalt surface

Zatrzymanie pojazdu przed torem ruchu innego użytkownika drogi jest możliwe wtedy, gdy w chwili powstania zagrożenia pojazd znajduje się w odległości większej niż droga potrzebna do jego zatrzymania. Często zdarza się, że od chwili zaistnienia zdarzenia do chwili podjęcia oględzin miejsca zdarzenia wilgotność nawierzchni jezdni, w wyniku działania warunków atmosferycznych, ulega zmianie. W artykule omówiono wpływ zmiany drogi zatrzymania pojazdu przy różnej wilgotności nawierzchni asfaltowej na podstawie przeprowadzonego eksperymentu oraz wizualizację śladów powstałych na mokrej nawierzchni asfaltowej po jej wyschnięciu.Stopping the vehicle in front of another road user’s traffic track is possible when, at the moment when the danger occurred, the vehicle’s distance is greater than the distance required to stop it. Often does it happen that since the time of the traffic incident to the time of the inspection, the humidity of the road surface changes as a result of the change of weather conditions. The article discusses the influence of the change of the vehicle stopping distance at different humidity levels of the asphalt surface on the basis of the conducted experiment and the visualization of the traces made on wet asphalt after drying

The Ångström (B1\text{}^{1}Σ+\text{}^{+} → A1\text{}^{1}Π) Band System of 13\text{}^{13}C16\text{}^{16}O: New Observations and Analyses

The emission spectrum of the Ångström system (B$\text{}^{1}$Σ$\text{}^{+}$ → A$\text{}^{1}$Π) of $\text{}^{13}$C$\text{}^{16}$O was recorded and analysed by classical photographical spectroscopy. Under high resolution and with a precision estimated to be 0.010-0.020 cm$\text{}^{-1}$ the bands 1-2, 1-7, and 0-6 were recorded for the first time and the 0-1, 0-2, 1-1, and 1-5 bands were rephotographed and reexaminated. After the rotational analysis of the bands the following constants were calculated: (1) the rotational constants B$\text{}_{v}$, D$\text{}_{v}$ for the B$\text{}^{1}$Σ$\text{}^{+}$ and A$\text{}^{1}$Π states; (2) the equilibrium constants B$\text{}_{e}$,α$\text{}_{e}$, D$\text{}_{e}$, andβ$\text{}_{e}$ for the B$\text{}^{1}$Σ$\text{}^{+}$ state; (3) theν$\text{}_{0}$ band origins. A combined analysis of the currently observedÅ ngström bands and the previously observed Herzberg (C$\text{}^{1}$Σ$\text{}^{+}$ → A$\text{}^{1}$Π) and the (E$\text{}^{1}$ Π → A$\text{}^{1}$Π) bands made it possible to perform a precise relative characteristic of the B$\text{}^{1}$ Σ$\text{}^{+}$(v=0 and 1), C$\text{}^{1}$Σ$\text{}^{+}$(v=0) and E$\text{}^{1}$Π(v=0) Rydberg levels in $\text{}^{13}$C$\text{}^{16}$O. Numerous rotational perturbations observed in the A$\text{}^{1}$ Π state were confronted with the perturbations predicted from the theoretical calculations

The study of the scope of visibility of a pedestrian equipped with a reflective element during the night time

W artykule omówiony został problem dostrzegania pieszego oświetlonego światłami mijania w porze nocnej. Przedstawione zostały wyniki badań dotyczące odległości postrzegania w światłach mijania pieszego nie posiadającego elementu odblaskowego a następnie wyposażonego w pryzmatyczną opaskę odblaskową umieszczoną na przedramieniu. Na podstawie wyników przeprowadzonych badań odniesiono się również do długości drogi zatrzymania pojazdu przy prędkości maksymalnie dozwolonej administracyjnie w danych warunkach drogowych oraz możliwości uniknięcia wypadku poprzez wykonanie manewru omijania lub zatrzymania pojazdu przed pieszym w oparciu o zmierzone odległości. Uzyskane wyniki badań poddano analizie statystycznej, która pozwoliła ocenić poprawność wnioskowania na ich podstawie.The article discusses the issue of the detection of a pedestrian illuminated with the DRL lights during the night time. There were presented the results of the study concerning the distance of perception of the pedestrian without a reflective element, and then, equipped with a prismatic reflective band on the forearm. The study was conducted with the presence of DRL lights. The results of the study were also the basis of the analysis of the stopping distance in the condition of maximum speed allowed administratively and the possibility of avoiding an accident by evading or stopping the vehicle before the pedestrian, based on the measured distances. The obtained results of the study were subjected to statistical analysis, which allowed to assess their correctness of reasoning based on them

Zastosowanie modelowania numerycznego w analizie pracy fragmentu sieci kanalizacji deszczowej

The increase in paved surfaces area in cities, in relation to the natural permeable areas, results in increased loads of pollutants transported by the storm sewage system directly to the receivers. Storm wastewater, as it was reported in literature, in dependence to the type and of urbanized basin and manner of drainage contains significant concentration of pollutants, mainly: Total Suspended Solids (TSS), Total Nitrogen (TN), Total Phosphorus (TP), heavy metals and oil derivatives. In according with the Water Framework Directive, in many European countries, the alternative methods of managing rain sewage are being developed, allowing retention and purification of storm water at the place of its formation. In the case of existing storm swage networks, the numerical analysis of hydraulic conditions and quantitative assessment of transported pollutants may support actions taken to protect the natural ecosystems against the exceeding the permissible concentrations of pollutants. This paper presents the results of modelling of hydraulic parameters and quality conditions of storm wastewater in a selected part of the urban storm sewage system. The USEPA’s (United States Environmental Protection Agency) software SWMM 5 (Storm Water Management Model) was applied to our studies. Three different rainfall events of various intensity and time duration were studied in our research. The conducted simulation tests enabled the analysis of the sewage flow rate, the canals filling height as well as the concentrations and loads of TSS, TP, TN at the outlet from the sewage system to the receiver. The results of the performed calculations showed that in the case of low-intensity rainfall, the unfavourable hydraulic conditions are present in the studied network. At the same time, the occurrence of storm event or extreme rainfall can lead to the flushing of deposits collected at the basin surface as well as at the bottom of pipes and the increase in loads of pollutants transported to the receiver.Wzrost udziału powierzchni utwardzonych w stosunku do naturalnych powierzchni przepuszczalnych miast powoduje wzrost ładunków zanieczyszczeń przenoszonych przez system kanalizacji deszczowej bezpośrednio do odbiorników. Ścieki deszczowe, jak wykazują badania literaturowe, w zależności od sposobu wykorzystania odwadnianej powierzchni zurbanizowanej przenoszą znaczne ładunki zanieczyszczeń, głównie zawiesiny ogólnej, ChZT, BZT, metali ciężkich czy związków ropopochodnych. Zgodnie z Ramową Dyrektywą Wodną w wielu krajach europejskich podejmowane są działania mające na celu rozwój alternatywnych metod zagospodarowania ścieków deszczowych, umożliwiających ich zatrzymywanie i oczyszczanie w miejscu ich powstawania. W przypadku istniejących już sieci deszczowych numeryczna analiza warunków hydraulicznych oraz ocena ilościowa transportowanych zanieczyszczeń może wspomóc działania podejmowane w celu ochrony naturalnych ekosystemów przed wzrostem/przekroczeniem dopuszczalnych stężeń zanieczyszczeń. W pracy zaprezentowano wyniki badań modelowych warunków hydraulicznych oraz jakościowych transportowanych ścieków deszczowych w wybranym fragmencie sieci deszczowej. Badania przeprowadzono w programie SWMM 5 przy założeniu zróżnicowanego natężenia deszczu oraz czasu jego trwania. Przeprowadzone badania symulacyjne umożliwiły analizę prędkości przepływu ścieków, wysokości napełnienia ścieków w przewodach, a także stężeń i ładunków zanieczyszczeń zawiesiny ogólnej, fosforu i azotu na wylocie z układu kanalizacyjnego do odbiornika. Wyniki przeprowadzonych obliczeń wykazały, iż w sieci kanalizacji deszczowej w przypadku opadów o niewielkim natężeniu panują niesprzyjające warunki hydrauliczne. Jednocześnie występowanie deszczów burzowych czy ekstremalnych może prowadzić do wymywania osadów zgromadzonych na dnie przewodów i wzrostu zanieczyszczeń przenoszonych do odbiornika

Varying Calcium Abundances in Solar Flares Seen by the Solar Maximum Mission

We report on calcium abundance A (Ca) estimates during the decay phases of 194 solar X-ray flares using archived data from the Bent Crystal Spectrometer (BCS) on the Solar Maximum Mission (operational 1980–1989). The abundances are derived from the ratio of the total calcium X-ray line emission in BCS channel 1 to that in neighboring continuum, with temperature from a satellite-to-resonance line ratio. Generally, the calcium abundance is found to be about 3 times the photospheric abundance, as previously found, indicating a “first ionization potential” (FIP) effect for calcium, which has a relatively low FIP value. The precision of the abundance estimates (referred to hydrogen on a logarithmic scale with A (H) = 12), is typically ∼± 0.01, enabling any time variations of A (Ca) during the flare decay to be examined. For a total of 270 short time segments with A (Ca) determined to better than 2.3% accuracy, many (106; 39%) showed variations in A (Ca) at the 3 σ level. For the majority, in 74 (70%) of these 106 segments A (Ca) decreased with time, and for 32 (30%) A (Ca) increased with time. For 79 out of 270 (29%) we observed constant or nearly constant A (Ca), and the remaining 85 (31%) with irregular time behavior. A common feature was the presence of discontinuities in the time behavior of A (Ca). Relating these results to the ponderomotive force theory of Laming, we attribute the nature of varying A (Ca) to the emergence of loop structures in addition to the initial main loop, each with its characteristic calcium abundance