1,036 research outputs found
High-frequency Oscillations in Small Magnetic Elements Observed with Sunrise/SuFI
We characterize waves in small magnetic elements and investigate their
propagation in the lower solar atmosphere from observations at high spatial and
temporal resolution. We use the wavelet transform to analyze oscillations of
both horizontal displacement and intensity in magnetic bright points found in
the 300 nm and the Ca II H 396.8 nm passbands of the filter imager on board the
Sunrise balloon-borne solar observatory. Phase differences between the
oscillations at the two atmospheric layers corresponding to the two passbands
reveal upward propagating waves at high frequencies (up to 30 mHz). Weak
signatures of standing as well as downward propagating waves are also obtained.
Both compressible and incompressible (kink) waves are found in the small-scale
magnetic features. The two types of waves have different, though overlapping,
period distributions. Two independent estimates give a height difference of
approximately 450+-100 km between the two atmospheric layers sampled by the
employed spectral bands. This value, together with the determined short travel
times of the transverse and longitudinal waves provide us with phase speeds of
29+-2 km/s and 31+-2 km/s, respectively. We speculate that these phase speeds
may not reflect the true propagation speeds of the waves. Thus, effects such as
the refraction of fast longitudinal waves may contribute to an overestimate of
the phase speed.Comment: 14 pages, 7 figure
A note on void ratio of fibre-reinforced soils
This technical note extends the concept of void ratio, presented traditionally in soil mechanics, for fibre-reinforced soils. Phase relationships related to the void ratio of fibre-reinforced soils are presented along with their definitions. A simple analytical model verified with experimental data for estimating the void ratio of fibre-reinforced soils is developed which can be used to express the compressibility of fibre-reinforced soils in geotechnical engineering applications. The results indicate that the void ratio of fibre-reinforced soils is dependent on the volume ratio of fibre-soil solid
Kinematics of Magnetic Bright Features in the Solar Photosphere
Convective flows are known as the prime means of transporting magnetic fields
on the solar surface. Thus, small magnetic structures are good tracers of the
turbulent flows. We study the migration and dispersal of magnetic bright
features (MBFs) in intergranular areas observed at high spatial resolution with
Sunrise/IMaX. We describe the flux dispersal of individual MBFs as a diffusion
process whose parameters are computed for various areas in the quiet Sun and
the vicinity of active regions from seeing-free data. We find that magnetic
concentrations are best described as random walkers close to network areas
(diffusion index, gamma=1.0), travelers with constant speeds over a
supergranule (gamma=1.9-2.0), and decelerating movers in the vicinity of flux
emergence and/or within active regions (gamma=1.4-1.5). The three types of
regions host MBFs with mean diffusion coefficients of 130 km^2/s, 80-90 km^2/s,
and 25-70 km^2/s, respectively. The MBFs in these three types of regions are
found to display a distinct kinematic behavior at a confidence level in excess
of 95%.Comment: 8 pages, 4 figure
Interdisciplinary evidence-based recommendations for the follow-up of testicular cancer patients: a joint effort
Detailed recommendations for the treatment of testicular cancer exist and due to the stringent application of the standard therapies, most patients can nowadays be cured. Moreover in the treatment of early stage disease, active surveillance is now a cornerstone of treatment. Hence there is a clear need for recommendations regarding the long term follow-up of these young patients. These have to be safe, feasible and the intensity of procedures have to reflect the known risk of recurrence. Different proposals have been published but they differ widely especially in terms of frequency and modality of imaging. In the last few years, new evidence has become available regarding the relapse pattern of different disease stages of testicular cancer, the use of imaging in follow-up and the risks of excessive radiation due to imaging, in particular with CT scans. In this article, an interdisciplinary, multinational working group has reviewed the evidence and based on this has formulated practical recommendations for the follow-up of patients with testicular cancer
МНОГОПАРАМЕТРОВЫЙ ЭЛЕКТРОМАГНИТНЫЙ МЕТОД КОНТРОЛЯ ЦИЛИНДРИЧЕСКИХ ТОКОПРОВОДОВ
In the paper the principle of electromagnetic transducer with a spatially periodic magnetic field to control, electrical and geometrical parameters of cylindrical elongated metal products. Obtain the basic mathematical equations that describe the distribution of the electromagnetic field inside the product, product in-between it and the transmitter coils, as well as agents of the converter. Ref. 7, Fig. 1.В работе рассмотрен принцип построения электромагнитного преобразователя с пространственно-периодическим полем для контроля магнитных, электрических и геометрических параметров цилиндрических протяженных металлических изделий. Получены основные математические выражения, описывающие распределение напряженности электромагнитного поля внутри изделия, между изделием и обмотками преобразователя, а также за проводниками преобразователя. Библ. 7, рис. 1.У роботі розглянуто принцип побудови електромагнітного перетворювача з просторово-періодичним полем для контролю магнітних, електричних і геометричних параметрів циліндричних протяжних металевих виробів. Отримано основні математичні вирази, що описують розподіл напруженості електромагнітного поля всередині виробу, між виробом і обмотками перетворювача, а також за провідниками перетворювача. Бібл. 7, рис. 1
Building cooperation through health initiatives: an Arab and Israeli case study
<p>Abstract</p> <p>Background</p> <p>Ongoing conflict in the Middle East poses a major threat to health and security. A project screening Arab and Israeli newborns for hearing loss provided an opportunity to evaluate ways for building cooperation. The aims of this study were to: a) examine what attracted Israeli, Jordanian and Palestinian participants to the project, b) describe challenges they faced, and c) draw lessons learned for guiding cross-border health initiatives.</p> <p>Methods</p> <p>A case study method was used involving 12 key informants stratified by country (3 Israeli, 3 Jordanian, 3 Palestinian, 3 Canadian). In-depth interviews were tape-recorded, transcribed and analyzed using an inductive qualitative approach to derive key themes.</p> <p>Results</p> <p>Major reasons for getting involved included: concern over an important health problem, curiosity about neighbors and opportunities for professional advancement. Participants were attracted to prospects for opening the dialogue, building relationships and facilitating cooperation in the region. The political situation was a major challenge that delayed implementation of the project and placed participants under social pressure. Among lessons learned, fostering personal relationships was viewed as critical for success of this initiative.</p> <p>Conclusion</p> <p>Arab and Israeli health professionals were prepared to get involved for two types of reasons: a) Project Level: opportunity to address a significant health issue (e.g. congenital hearing loss) while enhancing their professional careers, and b) Meta Level: concern about taking positive steps for building cooperation in the region. We invite discussion about roles that health professionals can play in building "cooperation networks" for underpinning health security, conflict resolution and global health promotion.</p
PlantSimLab - a modeling and simulation web tool for plant biologists.
BACKGROUND: At the molecular level, nonlinear networks of heterogeneous molecules control many biological processes, so that systems biology provides a valuable approach in this field, building on the integration of experimental biology with mathematical modeling. One of the biggest challenges to making this integration a reality is that many life scientists do not possess the mathematical expertise needed to build and manipulate mathematical models well enough to use them as tools for hypothesis generation. Available modeling software packages often assume some modeling expertise. There is a need for software tools that are easy to use and intuitive for experimentalists.
RESULTS: This paper introduces PlantSimLab, a web-based application developed to allow plant biologists to construct dynamic mathematical models of molecular networks, interrogate them in a manner similar to what is done in the laboratory, and use them as a tool for biological hypothesis generation. It is designed to be used by experimentalists, without direct assistance from mathematical modelers.
CONCLUSIONS: Mathematical modeling techniques are a useful tool for analyzing complex biological systems, and there is a need for accessible, efficient analysis tools within the biological community. PlantSimLab enables users to build, validate, and use intuitive qualitative dynamic computer models, with a graphical user interface that does not require mathematical modeling expertise. It makes analysis of complex models accessible to a larger community, as it is platform-independent and does not require extensive mathematical expertise
Retinal Angiogenesis Suppression through Small Molecule Activation of p53
Neovascular age-related macular degeneration is a leading cause of irreversible vision loss in the Western world. Cytokine-targeted therapies (such as anti-vascular endothelial growth factor) are effective in treating pathologic ocular angiogenesis, but have not led to a durable effect and often require indefinite treatment. Here, we show that Nutlin-3, a small molecule antagonist of the E3 ubiquitin protein ligase MDM2, inhibited angiogenesis in several model systems. We found that a functional p53 pathway was essential for Nutlin-3-mediated retinal antiangiogenesis and disruption of the p53 transcriptional network abolished the antiangiogenic activity of Nutlin-3. Nutlin-3 did not inhibit established, mature blood vessels in the adult mouse retina, suggesting that only proliferating retinal vessels are sensitive to Nutlin-3. Furthermore, Nutlin-3 inhibited angiogenesis in nonretinal models such as the hind limb ischemia model. Our work demonstrates that Nutlin-3 functions through an antiproliferative pathway with conceivable advantages over existing cytokine-targeted antiangiogenesis therapies
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