401 research outputs found
Beam-excited whistler waves at oblique propagation with relation to STEREO radiation belt observations
Isotropic electron beams are considered to explain the excitation of
whistler waves which have been observed by the STEREO satellite in the Earth's radiation belt.
Aside from their large amplitudes (~240 mV/m), another main signature is the strongly
inclined propagation direction relative to the ambient magnetic field. Electron
temperature anisotropy with <I>T</I><sub>e⊥</sub>><I>T</I><sub>e||</sub>, which preferentially generates parallel
propagating whistler waves, can be excluded as a free energy source.
The instability
arises due to the interaction of the Doppler-shifted cyclotron mode ω=−Ω<sub>e</sub>+<I>kV</I><sub>b</sub>cosθ with
the whistler mode in the wave number range
of <I>kc</I>/ω<sub>e</sub>≤1 (θ is the propagation angle
with respect to the background magnetic field direction, ω<sub>e</sub> is the electron plasma frequency
and Ω<sub>e</sub> the electron cyclotron frequency).
Fluid and kinetic dispersion analysis have been used to calculate the growth rate of the
beam-excited whistlers including the most important parameter dependencies.
One is the beam
velocity (<I>V</I><sub>b</sub>) which, for instability, has to be larger than about 2<I>V</I><sub>Ae</sub>, where <I>V</I><sub>Ae</sub> is the
electron Alfvén speed. With increasing <I>V</I><sub>Ae</sub> the propagation angle (θ) of the fastest growing
whistler waves shifts from θ~20° for <I>V</I><sub>b</sub>=2<I>V</I><sub>Ae</sub> to θ~80° for <I>V</I><sub>b</sub>=5<I>V</I><sub>Ae</sub>.
The growth rate is
reduced by finite electron temperatures and disappears if the electron plasma beta (β<sub>e</sub>)
exceeds β<sub>e</sub>~0.2.
In addition, Gendrin modes (<I>kc</I>/ω<sub>e</sub>≈1) are analyzed to determine the conditions
under which stationary nonlinear waves (whistler oscillitons) can exist. The corresponding
spatial wave profiles are calculated using the full nonlinear fluid approach. The results
are compared with the STEREO satellite
observations
Developing an app to provide physical and mental health benefits for menopausal women
Background: Menopause is the end of a women’s menstrual cycle and reproductive years. For some women the transition is without major problems; others struggle with various psychological and physical symptoms. Regular walking exercise can be an easy way to maintain physical and mental health. Previous focus groups revealed that women enjoy and want the social aspect of walking groups.
Objectives: The goal of this study is to test use and effectiveness of a walking app platform specific for menopausal women that allows them to connect with each other to schedule walks in Edmonton, and track the effect of walking on their symptom changes.
Methods: Women will be recruited from the Edmonton Menopause clinics and by word of mouth. Interested and consented women receive login information to use the app to schedule and sign-up for walks. Women will complete menopause-specific QOL and symptom questionnaires at their first login and will be prompted to complete them monthly thereafter. Women will also be asked to record their walking durations and intensities. Participating women will be invited to focus groups to discuss their experience using the app. Descriptive statistics will be applied to analyze data collected at the backend from questionnaires and surveys, and qualitative content analysis will be applied to analyze the audio-recorded focus groups.
Results: A prototypic online application has been created including a user manual.
Access is restricted and all potential participants will be screened after their first login by the research team prior to gaining full access. Women will then be able to use the app features for schedules and surveys. Data collected at the back end by the researchers will determine the use and effectiveness of the app and explore the impact of social walking on menopause symptom changes.
Conclusion: This is the first social platform of this kind created specifically for menopausal women. Ultimately we hope that this platform will empower women to seek lifestyle changes such as walking exercises and connect with each other on the communality of menopause. Testing the use and effectiveness of the app will help us to improve and further develop the app
Metabolomic profiles are gender, disease and time specific in the interleukin-10 gene-deficient mouse model of inflammatory bowel disease.
Metabolomic profiling can be used to study disease-induced changes in inflammatory bowel diseases (IBD). The aim of this study was to investigate the difference in the metabolomic profile of males and females as they developed IBD. Using the IL-10 gene-deficient mouse model of IBD and wild-type mice, urine at age 4, 6, 8, 12, 16, and 20 weeks was collected and analyzed by nuclear magnetic resonance (NMR) spectroscopy. Multivariate data analysis was employed to assess differences in metabolomic profiles that occurred as a consequence of IBD development and severity (at week 20). These changes were contrasted to those that occurred as a consequence of gender. Our results demonstrate that both IL-10 gene-deficient and wild-type mice exhibit gender-related changes in urinary metabolomic profile over time. Some male-female separating metabolites are common to both IL-10 gene-deficient and control wild-type mice and, therefore, appear to be related predominantly to gender maturation. In addition, we were able to identify gender-separating metabolites that are unique for IL-10 gene-deficient and wild-type mice and, therefore, may be indicative of a gender-specific involvement in the development and severity of the intestinal inflammation. The comparison of the gender-separating metabolomic profile from IL-10 gene-deficient mice and wild-type mice during the development of IBD allowed us to identify changes in profile patterns that appear to be imperative in the development of intestinal inflammation, but yet central to gender-related differences in IBD development. The knowledge of metabolomic profile differences by gender and by disease severity has potential clinical implications in the design of both biomarkers of disease as well as the development of optimal therapies
Визначення кількісного вмісту проціанідинів плодів глоду
Aim. To determine the quantitative content of procyanidins in hawthorn fruits.Results and discussion. It was found that the quantitative content of procianidinsin Crataegus succulentha Sarg. fruits was 1.45 % ± 0.02; C. prunifolia Sarg. – 1.24 % ± 0.05; C. pseudokyrtostila Klok. – 1.15 % ± 0.03; C. leiomonogyna Klok. – 1.28 % ± 0.04; C. arnoldii Sarg. – 1.38 %± 0.02; C. submollis Sarg. – 1.37 % ± 0.03; C. mollis Sarg. 1.48 % ± 0.01.Ехperimental part. The content of procyanidins was determined by the spectrophotometric method calculated with the reference to cyanidin chloride. The optical density of the test solution was measured at a wavelength of 545 nm. The study was performed on a Thermo Fisher Scientific model EVOVUTION 60S spectrophotometer.Conclusions. Procyanidins of fruits of 7 nonofficinal species of the genus Crataegus L. have been studied. It has been determined that all samples under research meet the requirements of the SPhU and EuPh by the indicator “Assay for procyanidins”, which should be at least 1 %.Цель. Установление количественного содержания процианидинов плодов боярышника.Результаты и их обсуждение. Установлено, что количественное содержание процианидинов в плодах Crataegus succulentha Sarg. составило 1,45 % ± 0,02; C. prunifolia Sarg. – 1,24 % ± 0,05; C. pseudokyrtostila Klok. – 1,15 % ± 0,03; C. leiomonogyna Klok. – 1,28 % ± 0,04; C. arnoldii Sarg. – 1,38 %± 0,02; C. submollis Sarg. – 1,37 % ± 0,03; C. mollis Sarg. 1,48 % ± 0,01.Экспериментальная часть. Содержание процианидинов в сырье определяли спектрофотометрическим методом в пересчете на цианидина хлорид. Оптическую плотность измеряли при длине волны 545 нм. Исследования проводили на спектрофотометре Thermo Fisher Scientific model EVOVUTION 60S.Выводы. Исследованы процианидины плодов 7 неофицинальных видов рода Crataegus L. Установлено, что все исследованные образцы отвечают требованиям ГФУ и EuPh по показателю «Количественное определение процианидинов», который должен быть не меньше 1 %.Мета. Встановлення кількісного вміступроціанідинів плодів глоду.Результати та їх обговорення. Встановлено, що кількісний вміст проціанідинів у плодах Crataegus succulentha Sarg. склав 1,45 % ± 0,02; C. prunifolia Sarg. – 1,24 % ± 0,05; C. pseudokyrtostila Klok. – 1,15 % ± 0,03; C. leiomonogyna Klok. – 1,28 % ± 0,04; C. arnoldii Sarg. – 1,38 % ± 0,02; C. submollis Sarg. – 1,37 % ± 0,03; C. mollis Sarg. 1,48 % ± 0,01.Експериментальна частина. Вміст проціанідинів у сировині визначали спектрофотометричним методом у перерахунку на ціанідину хлорид. Оптичну густину випробовуваного розчину вимірювали при довжині хвилі 545 нм. Дослідження проводили на спектрофотометрі Thermo Fisher Scientific model EVOVUTION 60S.Висновки. Досліджені проціанідини плодів 7 неофіційних видів роду Crataegus L. Встановлено, що усі досліджені зразки відповідають вимогам ДФУ та EuPh за показником «Кількісне визначення проціанідинів», який повинен бути не менше 1 %
Fluid Simulations of Three-Dimensional Reconnection that Capture the Lower-Hybrid Drift Instability
Fluid models that approximate kinetic effects have received attention
recently in the modelling of large scale plasmas such as planetary
magnetospheres. In three-dimensional reconnection, both reconnection itself and
current sheet instabilities need to be represented appropriately. We show that
a heat flux closure based on pressure gradients enables a ten moment fluid
model to capture key properties of the lower-hybrid drift instability (LHDI)
within a reconnection simulation. Characteristics of the instability are
examined with kinetic and fluid continuum models, and its role in the
three-dimensional reconnection simulation is analysed. The saturation level of
the electromagnetic LHDI is higher than expected which leads to strong kinking
of the current sheet. Therefore, the magnitude of the initial perturbation has
significant impact on the resulting turbulence.Comment: 20 pages, 9 figure
Particle Energization in an Expanding Magnetized Relativistic Plasma
Using a 2-1/2-dimensional particle-in-cell (PIC) code to simulate the
relativistic expansion of a magnetized collisionless plasma into a vacuum, we
report a new mechanism in which the magnetic energy is efficiently converted
into the directed kinetic energy of a small fraction of surface particles. We
study this mechanism for both electron-positron and electron-ion (mi/me=100, me
is the electron rest mass) plasmas. For the electron-positron case the pairs
can be accelerated to ultra-relativistic energies. For electron-ion plasmas
most of the energy gain goes to the ions.Comment: 7 pages text plus 5 figures, accepted for publication by Physical
Review Letter
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