1,154 research outputs found
The Cause of Photospheric and Helioseismic Responses to Solar Flares: High-Energy Electrons or Protons?
Analysis of the hydrodynamic and helioseismic effects in the photosphere
during the solar flare of July 23, 2002, observed by Michelson Doppler Imager
(MDI) on SOHO, and high-energy images from RHESSI shows that these effects are
closely associated with sources of the hard X-ray emission, and that there are
no such effects in the centroid region of the flare gamma-ray emission. These
results demonstrate that contrary to expectations the hydrodynamic and
helioseismic responses (''sunquakes") are more likely to be caused by
accelerated electrons than by high-energy protons. A series of multiple
impulses of high-energy electrons forms a hydrodynamic source moving in the
photosphere with a supersonic speed. The moving source plays a critical role in
the formation of the anisotropic wave front of sunquakes.Comment: 13 pages, 5 figures, ApJL in pres
СТАН ТА ПЕРСПЕКТИВИ РОЗВИТКУ ФРІЛАНСУ В УКРАЇНІ
In this article the key motives of freelance activity on the basis of the polls analysis of freelancers are considered. The tendencies of freelance market development in particular in the context of cities, are explored in Ukraine. It is described the division of Ukrainian freelancers according to the sphere of activity. The size and dynamics of pays of employees of this sphere of employment are analyzed. The main problems arising in the conditions of freelance activity areconsidered. Forecasts about freelance development in Ukraine by SWOT-analysis method are investigated.В данной статье рассмотрены основные мотивы фриланс- деятельности на основе анализа опросов фрилансеров. Исследованы тенденции развития рынка фриланса в Украине, в частности в разрезе городов. Охарактеризовано распределение украинских фрилансеров по сфере деятельности. Проанализированы размер и динамика заработка работников данной формы занятости. Рассмотрены основные препятствия, возникающие в условиях фриланс деятельности. Исследованы перспективы развития фриланса в Украине методом SWOT-анализа.В даній статті розглянуто основні мотиви фріланс-діяльності на основі аналізу опитувань фрілансерів. Досліджено тенденції розвитку ринку фрілансу в Україні, зокрема в розрізі міст. Охарактеризовано розподіл українських фрілансерів за сферою діяльності. Проаналізовано розмір та динаміку заробітку працівників даної форми зайнятості. Розглянуто основні перешкоди, що виникають в умовах фріланс-діяльності. Досліджено перспективи розвитку фрілансу в Україні методом SWOT-аналізу
Non-obvious Problems in Clark Electrode Application at Elevated Temperature and Ways of Their Elimination
Well-known cause of frequent failures of closed oxygen sensors is the appearance of gas bubbles in the electrolyte. The problem is traditionally associated with insufficient sealing of the sensor that is not always true. Study of a typical temperature regime of measurement system based on Clark sensor showed that spontaneous release of the gas phase is a natural effect caused by periodic warming of the sensor to a temperature of the test liquid. The warming of the sensor together with the incubation medium causes oversaturation of electrolyte by dissolved gases and the allocation of gas bubbles. The lower rate of sensor heating in comparison with the medium reduces but does not eliminate the manifestation of this effect. It is experimentally established, that with each cycle of heating of measuring system up to 37 ∘ C followed by cooling the volume of gas phase in the electrolyte (KCl; 60 g/L; 400 L) increased by 0.6 L approximately. Thus, during just several cycles it can dramatically degrade the characteristics of the sensor. A method was developed in which the oxygen sensor is heated in contact with the liquid, (depleted of dissolved gases), allowing complete exclusion of the above-mentioned effect
Synthetic Melatoninergic Ligands: Achievements and Prospects
TesisLa investigación que se presenta tiene como objetivo principal analizar las
ventajas competitivas de las empresas representativas de bebidas gaseosas en
el Perú durante el periodo 2015-2016. Se trabajó con un diseño de
investigación no experimental porque la variable no se ve afectada por la
investigación a estudiar, el tipo de diseño es transversal porque se ciñe al
estudio en un tiempo determinado; descriptiva porque solo se realizó el análisis
y descripción de las teorías de las ventajas competitivas en las empresas
representativas de bebidas gaseosas en el Perú durante el periodo 2015-2016
y cualitativo porque se basa en recolección de datos sin medición numérica
como el análisis documental, memoria anual y entrevistas de profundidad a
colaboradores estratégicos de las empresas Arca Continental Lindley y Aje
Group
Antisocial behaviour and teacher–student relationship quality: The role of emotion‐related abilities and callous–unemotional traits
Background: Childhood antisocial behaviour has been associated with poorer teacher-student relationship (TSR) quality. It is also well-established that youth with antisocial behaviour have a range of emotion-related deficits, yet the impact of these students’ emotion-related abilities on the TSR is not understood. Furthermore, the addition of the Limited Prosocial Emotions specifier in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) indicates that understanding the role of callous-unemotional (CU) traits for youth with antisocial behaviour problems is of particular importance.
Aims: The aim of this study was to investigate the association between antisocial behaviour difficulties and the TSR by examining the influence of emotion-related abilities and CU traits.
Sample: Twelve teachers from 10 primary schools provided anonymised information on 108 children aged 6-11 years.
Results: Antisocial behaviour was associated with higher teacher-student conflict (but not closeness) as well as higher emotion lability/negativity and lower emotion understanding/empathy. Emotion lability/negativity was associated with higher teacher-student conflict (but not closeness), and emotion understanding/empathy was associated with lower teacher-student conflict and higher closeness. CU traits was associated with higher teacher-student conflict and lower teacher-student closeness (controlling for antisocial behaviour more broadly). We found no evidence of a moderating effect of CU traits or emotion-related abilities on the association between antisocial behaviour and TSR quality.
Conclusions: Interventions for behaviour difficulties should consider teacher-student relationships in the classroom. Strategies which aim to improve teacher-student closeness as well as reduce teacher-student conflict may be of particular value to students with high CU traits
Observation of an Excited Bc+ State
Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+π+π- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bc∗(2S31)+ state reconstructed without the low-energy photon from the Bc∗(1S31)+→Bc+γ decay following Bc∗(2S31)+→Bc∗(1S31)+π+π-. A second state is seen with a global (local) statistical significance of 2.2σ (3.2σ) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date
A pulsating auroral X-ray hot spot on Jupiter
Jupiter's X-ray aurora has been thought to be excited by energetic sulphur and oxygen ions precipitating from the inner magnetosphere into the planet's polar regions(1-3). Here we report high-spatial-resolution observations that demonstrate that most of Jupiter's northern auroral X-rays come from a 'hot spot' located significantly poleward of the latitudes connected to the inner magnetosphere. The hot spot seems to be fixed in magnetic latitude and longitude and occurs in a region where anomalous infrared(4-7) and ultraviolet(8) emissions have also been observed. We infer from the data that the particles that excite the aurora originate in the outer magnetosphere. The hot spot X-rays pulsate with an approximately 45-min period, a period similar to that reported for high-latitude radio and energetic electron bursts observed by near-Jupiter spacecraft(9,10). These results invalidate the idea that jovian auroral X-ray emissions are mainly excited by steady precipitation of energetic heavy ions from the inner magnetosphere. Instead, the X-rays seem to result from currently unexplained processes in the outer magnetosphere that produce highly localized and highly variable emissions over an extremely wide range of wavelengths.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/62624/1/4151000a.pd
Scientific Rationale of Saturn's In Situ Exploration
Remote sensing observations meet some limitations when used to study the bulk atmospheric composition of the giant planets of our solar system. A remarkable example of the superiority of in situ probe measurements is illustratedby the exploration of Jupiter, where key measurements such as the determination of the noble gases abundances and the precise measurement of the helium mixing ratio have only been made available through in situ measurements by the Galileo probe. This paper describes the main scienti-c goals to be addressed by the future in situ exploration of Saturn placing the Galileo probe exploration of Jupiter in a broader context and before the future probe exploration of the more remote ice giants. In situ exploration of Saturn's atmosphere addresses two broad themes that are discussedthroughout this paper : rst, the formation history of our solar system and second, the processes at play in planetary atmospheres. In this context, we detail the reasons why measurements of Saturn's bulk elemental and isotopiccomposition would place important constraints on the volatile reservoirs in the protosolar nebula. We also show that the in situ measurement of CO (or any other disequilibrium species that is depleted by reaction with water) in Saturn's upper troposphere may help constraining its bulk OH ratio. We compare predictions of Jupiter and Saturn's bulk compositions from different formation scenarios, and highlight the key measurements required to distinguish competing theories to shed light on giant planet formation as a common process in planetary systems with potential applications to mostextrasolar systems. In situ measurements of Saturn's stratospheric and tropospheric dynamics, chemistry and cloud-forming processes will provide access to phenomena unreachable to remote sensing studies. Dierent mission architectures are envisaged, which would benet from strong international collaborations, all based on an entry probe that would descend through Saturn's stratosphere and troposphere under parachute down to a minimum of 10 bars of atmospheric pressure. We rally discuss the science payload required on a Saturn probe to match the measurement requirements
Split or straight? Evidence of the effects of work schedules on workers’ well-being, time use, and productivity
About half of all employees in Spain are on a daytime split work schedule, i.e. they typically work for 5 h in the morning, take a 2-hour break at lunch time, and work for another 3 h in the afternoon/evening. This paper studies the effects of split work schedule on workers’ psychological well-being, daily time use, and productivity. Using cross-sectional data from the 2002 to 2003 Spanish Time Use Survey, I find that female split-shifters experience an increased feeling of being at least sometimes overwhelmed by tasks and not having enough time to complete them. On working days, a split work schedule is positively related to time spent on the job, sleeping, and eating and drinking, and negatively associated with time spent on housework, parental child care, and leisure activities. Most of the time-use effects are similar across the sexes, and only a few of the time reductions are partly made up on days off. I also find that the split work schedule is associated with lower hourly wages
Observation of the Decay Λ0b→Λ+cτ−¯ν
The first observation of the semileptonic b-baryon decay Λb0→Λc+τ-ν¯τ, with a significance of 6.1σ, is reported using a data sample corresponding to 3 fb-1 of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ- lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+π-π+π-) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λb0→Λc+τ-ν¯τ)=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λb0→Λc+π-π+π-. The ratio of semileptonic branching fractions R(Λc+)B(Λb0→Λc+τ-ν¯τ)/B(Λb0→Λc+μ-ν¯μ) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λb0→Λc+μ-ν¯μ contributes to the last term. This result is in agreement with the standard model prediction
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