179 research outputs found
Hard X-ray properties of NuSTAR blazars
Context. Investigation of the hard X-ray emission properties of blazars is
key to the understanding of the central engine of the sources and associated
jet process. In particular, simultaneous spectral and timing analyses of the
intra-day hard X-ray observations provide us a means to peer into the compact
innermost blazar regions, not accessible to our current instruments. Aims. The
primary objective of the work is to associate the observed hard X-ray
variability properties in the blazars to their flux and spectral states,
thereby, based on the correlation among them, extract the details about the
emission regions and the processes occurring near the central engine. Methods.
We carried out timing, spectral and cross-correlation analysis of 31 NuSTAR
observations of 13 blazars. We investigated the spectral shapes of the sources
using single power-law, broken power-law and log-parabola models. We also
studies the co-relation between the soft and the hard emission using
z-transformed discrete correlation function. Results. We found that for most of
the sources the hard X-ray emission can be well represented by log-parabola
model; and that the spectral slopes for different blazar sub-classes are
consistent with so called blazar sequence. We noted a close connection between
the flux and spectral slope within the source sub-class in the sense that high
flux and/or flux states tend to be harder in spectra. In BL Lacertae objects,
assuming particle acceleration by diffusive shocks and synchrotron cooling as
the dominant processes governing the observed flux variability, we constrain
the magnetic field of the emission region to be a few gauss; whereas in
flat-spectrum radio quasars, using external Compton models, we estimate the
energy of the lower end of the injected electrons to be a few Lorentz factors.Comment: 12 figures, 21 pages, A&A accepte
The experiences of adults living with epilepsy : an interpretive description
A qualitative interpretive description study was conducted to explore adults’ experiences of living with epilepsy. Adults integrate epilepsy into their daily lives; however, there is dearth of literature that explores their lived experiences. Semi-structured interviews were conducted with nine participants recruited from two health clinics situated in northern Ontario, Canada. The main theme was epilepsy as a temporal journey accompanied by others who knew of their past and present experiences, and future aspirations. The past included the onset of epilepsy and accompanied losses. The present was the balance between threats and well-being. Envisioned future was facilitated by hope. Each subtheme built upon the preceding in an attempt to create well-being and strive towards their envisioned future. Suggestions for nursing practice include fostering understanding in the past, promoting the creation of well-being in the present, and inspiring hope towards the future envisioned life.Master of Science (MSc) in Nursin
Sub two-cycle soliton-effect pulse compression at 800 nm in Photonic Crystal Fibers
The possibility of soliton self-compression of ultrashort laser pulses down
to the few-cycle regime in photonic crystal fibers is numerically investigated.
We show that efficient sub-two-cycle temporal compression of nanojoule-level
800 nm pulses can be achieved by employing short (typically 5-mm-long)
commercially available photonic crystal fibers and pulse durations of around
100 fs, regardless of initial linear chirp, and without the need of additional
dispersion compensation techniques. We envisage applications in a new
generation of compact and efficient sub-two cycle laser pulse sources.Comment: 16 pages, 6 figure
Seasonal food insecurity among farm workers in the Northern Cape, South Africa
Very little is known about seasonal hunger in South Africa, or about the food security and
nutritional status of farm workers. This article identifies a pathway to seasonal hunger—through
intra-annual fluctuations in agricultural employment and income—that is underanalyzed in the
literature. We report on findings from a year-long data collection process, comprising baseline
and endline surveys and monthly monitoring of three food security indicators, with a sample
of 195 female farm workers in the Northern Cape province in South Africa. The three monthly
monitoring indicators—the Household Food Insecurity Access Scale (HFIAS), Dietary Diversity
Score (DDS), and Coping Strategies Index (CSI)—which measure di erent aspects of food insecurity,
are analyzed to determine whether and to what extent food security fluctuates seasonally in our
sample. HFIAS results show unambiguous evidence of seasonal food insecurity, with the highest
prevalence (88 percent experiencing severe food insecurity) and severity during the low employment
winter period, and lowest prevalence (49 percent) and severity during the summer harvest, which
corresponds with relatively higher employment and earnings. The DDS results show evidence
of highest dietary diversity during summer and the CSI results reveal the need to employ coping
strategies to deal with intensified food insecurity during winter
Russian language skills and employment in the Former Soviet Union
During the Soviet era, proficiency in the Russian language was often a ticket to attractive employment opportunities in the member republics. Does it still contribute to securing employment in the former Soviet republics after two decades of transition? Using data from Armenia, Azerbaijan and Georgia in the years 2008-2010, this paper demonstrates that Russian language skills remain economically valuable. The baseline estimates suggest that Russian language skills increase probability of employment by about 6 (males) and 9 (females) percentage points. Our results bear important implications for the ongoing debates on language policies in the post-Soviet countries
Findings from a cluster randomised trial of unconditional cash transfers in Niger.
Unconditional cash transfers (UCTs) are used as a humanitarian intervention to prevent acute malnutrition, despite a lack of evidence about their effectiveness. In Niger, UCT and supplementary feeding are given during the June-September "lean season," although admissions of malnourished children to feeding programmes may rise from March/April. We hypothesised that earlier initiation of the UCT would reduce the prevalence of global acute malnutrition (GAM) in children 6-59 months old in beneficiary households and at population level. We conducted a 2-armed cluster-randomised controlled trial in which the poorest households received either the standard UCT (4 transfers between June and September) or a modified UCT (6 transfers from April); both providing 130,000 FCFA/£144 in total. Eligible individuals (pregnant and lactating women and children 6- 0.05), despite improved food security (p < 0.05), possibly driven by increased fever/malaria in children (p < 0.001). Nonfood related drivers of malnutrition, such as disease, may limit the effectiveness of UCTs plus supplementary feeding to prevent malnutrition in this context. Caution is required in applying the findings of this study to periods of severe food insecurity
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