Several proteins involved in DNA repair and DNA damage signaling have been shown to produce discrete foci in response to ionizing radiation. These foci are believed to co-localize to DSB and referred ...to as ionizing radiation-induced foci (IRIF) or DNA repair foci.
Recent studies have revealed that some residual IRIF remain in cells for a relatively long time after irradiation, and have indicated a possible correlation between radiosensitivity of cells and residual IRIF. Remarkably, residual foci are significantly larger in size than the initial foci. Increase in the size of IRIF with time upon irradiation has been found in various cell types and has partially been correlated with dynamics and fusion of initial foci.
Although it is admitted that the number of IRIF reflect that of DSB, several studies report a lack of correlation between kinetics for IRIF and DSB and a lack of co-localization between DSB repair proteins. These studies suggest that some proportion of residual IRIF that depend on cell type, dose, and post-irradiation time may represent alternations in chromatin structure after DSB have been repaired or misrepaired. While precise functions of residual foci are presently unknown, their possible link to remaining chromatin alternations, nuclear matrix, apoptosis, delayed repair and misrejoining of DSB, activity of several kinases, phosphatases, and checkpoint signaling has been suggested. Another intriguing possibility is that some of DNA repair foci may mark break-points at chromosomal aberrations (CA). While this possibility has not been confirmed substantially, the residual foci seem to be useful for biological dosimetry and estimation of individual radiosensitivity in radiotherapy of cancer.
The LHCb simulation application, Gauss, consists of two independent phases, the generation of the primary event and the tracking of particles produced in the experimental setup. For the LHCb ...experimental program it is particularly important to model B meson decays: the EvtGen code developed in CLEO and BABAR has been chosen and customized for non-coherent B production as occuring in pp collisions at the LHC. The initial proton-proton collision is provided by a different generator engine, currently PYTHIA 6 for massive production of signal and generic pp collisions events. Beam gas events, background events originating from proton halo, cosmics and calibration events for different detectors can be generated in addition to pp collisions. Different generator packages as available in the physics community or specifically developed in LHCb are used for the different purposes. Running conditions affecting the generated events such as the size of the luminous region, the number of collisions occuring in a bunch crossing and the number of spill-over events from neighbouring bunches are modeled via dedicated algorithms appropriately configured. The design of the generator phase of Gauss will be described: a modular structure with well defined interfaces specific to the various tasks, e.g. pp collisions, particle decays, selections, etc. has been chosen. Different implementations are available for the various tasks allowing selecting and combining them as most appropriate at run time as in the case of PYTHIA 6 for pp collisions or HIJING for beam gas. The advantages of such structure, allowing for example to adopt transparently new generators packages, will be discussed.
Whether the use of mobile phones (MP) represents a health hazard is still under debate. As part of the attempts to resolve this uncertainty, there has been an extensive characterization of the ...electromagnetic fields MP emit and receive. While the radiofrequencies (RF) have been studied exhaustively, the static magnetic fields (SMF) have received much less attention, regardless of the fact there is a wealth of evidence demonstrating their biological effects. We performed 2D maps of the SMF at several distances from the screen of 5 MP (models between 2013 and 2018) using a tri-axis magnetometer. We built a mathematical model to fit our measurements, extrapolated them down to the phones' screen, and calculated the SMF on the skin of a 3D head model, showing that exposure is in the µT to mT range. Our literature survey prompts the need of further research not only on the biological effects of SMF and their gradients, but also on their combination with extremely low frequency (ELF) and RF fields. The study of combined fields (SMF, ELF, and RF) as similar as possible to the ones that occur in reality should provide a more sensible assessment of potential risks.
The aim of this study was to research the cost effectiveness of creating forest reclamation complexes on slopes, as well as to determine the patterns of their orographic dynamics, taking into account ...environmental aspects in arid conditions. With the help of modeling agroforestry landscapes, we established forest plantations created from Lanceolate ash (Fraxinus lanceolata) in arid climatic conditions on sloping lands, the cost of planting of which is EUR 1202–EUR 1453 per ha of forest. The specific capital intensity of the arrangement of land use by forest stands is EUR 24–EUR 63 per hectare of afforested plot, while 5–11% accounts for the cost of logging of forest care and 2–30% for the inclusion of a hydraulic element in forest reclamation systems. The monetary equivalent of the return on these investments in the form of prevented damage from soil erosion and air pollution is EUR 333–EUR 940 per hectare of afforested plot per year. This economic effect increases with the growth of the protective forest cover of the plot (by reducing the interband space) by almost 3 times. The benefit–cost ratio for all forest reclamation strategies on slopes is greater than 1, which confirms the high efficiency and expediency of capital investments in forest reclamation activities on slope lands to preserve the land resources of various regions.
The aim of this study was to study the effectiveness and economic efficiency of the impact of agroforestry complexes on the adaptation of agriculture to climate change in the south of the Russian ...Plain. It has been established that this manifests quantitatively in a significant decrease (by almost a third) in the area of wind-destroyed lands and drought-dead crops in farms protected by forest strips compared with open agricultural territories. The calculation of direct damage prevented by protective forest plantations from degradation and loss of soil fertility as a result of dust storms and indirect damage prevented by protective forest plantations from crop loss as a result of extreme droughts shows that the total amount of remuneration received by farmers from agroforestry in connection with the placement of a forest-forming element in their fields is EUR 317–1239 ha−1 year−1. This value is the contribution of agroforestry to adaptation to climate change and is subject to zonal dynamics—it depends on natural and climatic conditions. The application developed as part of this research has value for decision makers, since it allows for preliminary assessment of the effectiveness and efficiency of agroforestry for various areas of farms and various natural zones.
Earphones (EP) are a worldwide, massively adopted product, assumed to be innocuous provided the recommendations on sound doses limits are followed. Nevertheless, sound is not the only physical ...stimulus that derives from EP use, since they include a built-in permanent magnet from which a static magnetic field (SMF) originates. We performed 2D maps of the SMF at several distances from 6 models of in-ear EP, showing that they produce an exposure that spans from ca. 20 mT on their surface down to tens of μT in the inner ear. The numerous reports of bioeffects elicited by SMF in that range of intensities (applied both acutely and chronically), together with the fact that there is no scientific consensus over the possible mechanisms of interaction with living tissues, suggest that caution could be recommendable. In addition, more research is warranted on the possible effects of the combination of SMF with extremely low frequency and radiofrequency fields, which has so far been scarcely studied. Overall, while several open questions about bioeffects of SMF remain to be addressed by the scientific community, we find sensible to suggest that the use of air-tube earphones is probably the more conservative, cautious choice.
•Experimental mapping of the static magnetic fields near 6 earphones.•Physical modeling of the measured fields allows extrapolation and simulation.•3D simulations allow for visualization of field distribution in the ear.•Field intensity and gradients, plus their combination with RF/ELF should be studied.
Abstract
The effect of static and alternating magnetic fields on the conformation of nucleoids in cells of different types is considered. The model of slow and nonuniform rotation of the charged DNA ...domain is used. An equation is obtained for the resonance frequencies of the alternating magnetic field.
The noise of a modern regional aircraft was measured using the beamforming method during flight tests in the landing approach configuration with extended landing gear and deflected high-lift devices ...(slats and flaps). The localization and ranking of aircraft noise sources for full-scale Reynolds numbers has been carried out. Comparison of the flight test results with the results of acoustic measurements of airframe noise for a large-scale wing model obtained earlier at DNW-NWB showed good agreement between noise measurements of the large-scale model, scaled to full size, with the results for the airframe noise of an aircraft wing in flight tests.
The importance of jet noise for prospective supersonic transport (SST) in takeoff and climb modes dictates the need to develop methods for reducing jet noise and their subsequent validation in large- ...and full-scale tests. This paper presents the results of Russia’s first ground acoustic tests of a rectangular nozzle with a noise suppression system, installed on a subsonic aircraft engine to demonstrate the technology. The authors studied a rectangular beveled nozzle with an ejector and screens—elements of the SST airframe. The test results were compared for three nozzle geometries: a round nozzle corresponding to measurements for the original engine without modifications, a rectangular nozzle without screens, and a rectangular nozzle with screens. It was found that when the rectangular nozzle without screens is used, there two opposite effects occur: noise amplification compared to the round nozzle for angles of observation close to the jet axis, and noise attenuation at angles of observation close to the fan rotation plane. Installing screens increases noise up to 5 dB in the low-frequency region below 150 Hz and reduces noise by 2 dB for frequencies higher than 250 Hz. Estimation of community noise in the EPNL metric showed that this rectangular nozzle with the noise suppression system has the effect of reducing community noise in comparison with the baseline round nozzle.
The history of LHCb Belyaev, I.; Carboni, G.; Harnew, N. ...
European physical journal H,
12/2021, Letnik:
46, Številka:
1
Journal Article
Recenzirano
Odprti dostop
In this paper, we describe the history of the LHCb experiment over the last three decades, and its remarkable successes and achievements. LHCb was conceived primarily as a
b
-physics experiment, ...dedicated to
CP
violation studies and measurements of very rare
b
decays; however, the tremendous potential for
c
-physics was also clear. At first data taking, the versatility of the experiment as a general-purpose detector in the forward region also became evident, with measurements achievable such as electroweak physics, jets and new particle searches in open states. These were facilitated by the excellent capability of the detector to identify muons and to reconstruct decay vertices close to the primary
pp
interaction region. By the end of the LHC Run 2 in 2018, before the accelerator paused for its second long shut down, LHCb had measured the CKM quark mixing matrix elements and
CP
violation parameters to world-leading precision in the heavy-quark systems. The experiment had also measured many rare decays of
b
and
c
quark mesons and baryons to below their Standard Model expectations, some down to branching ratios of order 10
-
9
. In addition, world knowledge of
b
and
c
spectroscopy had improved significantly through discoveries of many new resonances already anticipated in the quark model, and also adding new exotic four and five quark states. The paper describes the evolution of the LHCb detector, from conception to its operation at the present time. The authors’ subjective summary of the experiment’s important contributions is then presented, demonstrating the wide domain of successful physics measurements that have been achieved over the years.
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