scholarly journals THE HIGH-ENERGY PROPERTIES OF 3C 454.3: A FOUR-YEAR STUDY

2012 ◽  
Vol 08 ◽  
pp. 404-407 ◽  
Author(s):  
◽  
STEFANO VERCELLONE
Keyword(s):  
Gamma Ray ◽  
High Energy ◽  
Short Term ◽  
Multi Wavelength ◽  
Vela Pulsar ◽  
Short And Long Term ◽  
Γ Ray ◽  
Short Term Variability ◽  
Daily Time

The blazar 3C 454.3 has become the most active and brightest γ-ray source of the sky, earning the nickname of Crazy Diamond. The short-term variability in the γ-ray energy band and the extremely high peak fluxes reached during intense flaring episodes make 3C 454.3 one of the best targets to investigate the blazar jet properties. We will review four years of observational properties of this remarkable source, discussing both short- and long-term multi-wavelength campaigns, with particular emphasis on the recent flaring episode which occurred on 2010 November 20, when 3C 454.3 reached on a daily time-scale a gamma-ray flux (E > 100 MeV) higher than 6 × 10-5 photons cm-2 s-1, about six times the flux of the brightest γ-ray steady source, the Vela Pulsar.

scholarly journals Modelling large timescale and small timescale service variability

2019 ◽  
Vol 293 (1) ◽  
pp. 123-140
Author(s):  
Marco Gribaudo ◽  
Illés Horváth ◽  
Daniele Manini ◽  
Miklós Telek
Keyword(s):  
Service Time ◽  
Large Scale ◽  
Service Time Distribution ◽  
Efficient Computation ◽  
Short Term ◽  
Service Unit ◽  
Long Term Effect ◽  
Short And Long Term ◽  
Short Term Variability

Abstract The performance of service units may depend on various randomly changing environmental effects. It is quite often the case that these effects vary on different timescales. In this paper, we consider small and large scale (short and long term) service variability, where the short term variability affects the instantaneous service speed of the service unit and a modulating background Markov chain characterizes the long term effect. The main modelling challenge in this work is that the considered small and long term variation results in randomness along different axes: short term variability along the time axis and long term variability along the work axis. We present a simulation approach and an explicit analytic formula for the service time distribution in the double transform domain that allows for the efficient computation of service time moments. Finally, we compare the simulation results with analytic ones.

scholarly journals Radio Galaxies—The TeV Challenge

Galaxies ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 23 ◽  
Author(s):  
Bindu Rani
Keyword(s):  
Gamma Ray ◽  
Radio Galaxies ◽  
High Energy ◽  
Energy Emission ◽  
Long Baseline ◽  
Multi Wavelength ◽  
Emission Models ◽  
Γ Ray ◽  
Radiation Processes ◽  
High Energy Emission

Over the past decade, our knowledge of the γ -ray sky has been revolutionized by ground- and space-based observatories by detecting photons up to several hundreds of tera-electron volt (TeV) energies. A major population of the γ -ray bright objects are active galactic nuclei (AGN) with their relativistic jets pointed along our line-of-sight. Gamma-ray emission is also detected from nearby misaligned AGN such as radio galaxies. While the TeV-detected radio galaxies ( T e V R a d ) only form a small fraction of the γ -ray detected AGN, their multi-wavelength study offers a unique opportunity to probe and pinpoint the high-energy emission processes and sites. Even in the absence of substantial Doppler beaming T e V R a d are extremely bright objects in the TeV sky (luminosities detected up to 10 45 erg s − 1 ), and exhibit flux variations on timescales shorter than the event-horizon scales (flux doubling timescale less than 5 min). Thanks to the recent advancement in the imaging capabilities of high-resolution radio interferometry (millimeter very long baseline interferometry, mm-VLBI), one can probe the scales down to less than 10 gravitational radii in T e V R a d , making it possible not only to test jet launching models but also to pinpoint the high-energy emission sites and to unravel the emission mechanisms. This review provides an overview of the high-energy observations of T e V R a d with a focus on the emitting sites and radiation processes. Some recent approaches in simulations are also sketched. Observations by the near-future facilities like Cherenkov Telescope Array, short millimeter-VLBI, and high-energy polarimetry instruments will be crucial for discriminating the competing high-energy emission models.

scholarly journals THE 2010 M 87 VHE FLARE AND ITS ORIGIN: THE MULTI-WAVELENGTH PICTURE

2012 ◽  
Vol 08 ◽  
pp. 184-189 ◽  
Author(s):  
◽  
M. RAUE ◽  
L. STAWARZ ◽  
D. MAZIN ◽  
P. COLIN ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Galactic Nuclei ◽  
High Energy ◽  
Massive Black Hole ◽  
Long Baseline ◽  
Multi Wavelength ◽  
Very High Energy ◽  
Γ Ray ◽  
Very Long Baseline Array ◽  
Innermost Region

The giant radio galaxy M 87, with its proximity (16 Mpc) and its very massive black hole ((3-6) × 109 M⊙), provides a unique laboratory to investigate very high energy (E>100 GeV; VHE) gamma-ray emission from active galactic nuclei and, thereby, probe particle acceleration to relativistic energies near supermassive black holes (SMBH) and in relativistic jets. M 87 has been established as a VHE γ-ray emitter since 2005. The VHE γ-ray emission displays strong variability on timescales as short as a day. In 2008, a rise in the 43 GHz Very Long Baseline Array (VLBA) radio emission of the innermost region (core; extension of < 100 R s ; Schwarzschild radii) was found to coincide with a flaring activity at VHE. This had been interpreted as a strong indication that the VHE emission is produced in the direct vicinity of the SMBH. In 2010 a flare at VHE was again detected triggering further multi-wavelength (MWL) observations with the VLBA, Chandra, and other instruments. At the same time, M 87 was also observed with the Fermi-LAT telescope at MeV/GeV energies, the European VLBI Network (EVN), and the Liverpool Telescope (LT). Here, preliminary results from the 2010 campaign will be reported.

scholarly journals Maternal Vaginal Ureaplasma spp. Colonization in Early Pregnancy Is Associated with Adverse Short- and Long-Term Outcome of Very Preterm Infants

Children ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 276
Author(s):  
Judith Rittenschober-Böhm ◽  
Tanja Habermüller ◽  
Thomas Waldhoer ◽  
Renate Fuiko ◽  
Stefan M. Schulz ◽  
...  
Keyword(s):  
Preterm Infants ◽  
Early Pregnancy ◽  
Short Term ◽  
Term Outcome ◽  
Long Term Outcome ◽  
Very Preterm Infants ◽  
Very Preterm ◽  
Vaginal Colonization ◽  
Short And Long Term

Vaginal colonization with Ureaplasma (U.) spp. has been shown to be associated with adverse pregnancy outcome; however, data on neonatal outcome are scarce. The aim of the study was to investigate whether maternal vaginal colonization with U. spp. in early pregnancy represents a risk factor for adverse short- or long-term outcome of preterm infants. Previously, 4330 pregnant women were enrolled in an observational multicenter study, analyzing the association between vaginal U. spp. colonization and spontaneous preterm birth. U. spp. colonization was diagnosed via PCR analysis from vaginal swabs. For this study, data on short-term outcome were collected from medical records and long-term outcome was examined via Bayley Scales of Infant Development at 24 months adjusted age. Two-hundred-and-thirty-eight children were born <33 weeks gestational age. After exclusion due to asphyxia, malformations, and lost-to-follow-up, data on short-term and long-term outcome were available from 222 and 92 infants, respectively. Results show a significant association between vaginal U. spp. colonization and severe intraventricular hemorrhage (10.4% vs. 2.6%, p = 0.03), retinopathy of prematurity (21.7% vs. 10.3%, p = 0.03), and adverse psychomotor outcome (24.3% vs. 1.8%, OR 13.154, 95%CI 1.6,110.2, p = 0.005). The data suggest an association between vaginal U. spp. colonization in early pregnancy and adverse short- and long-term outcome of very preterm infants.

scholarly journals Spatio-temporal associations of air pollutant concentrations, GP respiratory consultations and respiratory inhaler prescriptions: a 5-year study of primary care in the borough of Lambeth, South London

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Mark Ashworth ◽  
◽  
Antonis Analitis ◽  
David Whitney ◽  
Evangelia Samoli ◽  
...  
Keyword(s):  
Primary Care ◽  
Negative Binomial ◽  
Hospital Admissions ◽  
Air Pollutant ◽  
Respiratory Morbidity ◽  
Short Term ◽  
Short Term Exposure ◽  
Short And Long Term ◽  
Spatio Temporal

Abstract Background Although the associations of outdoor air pollution exposure with mortality and hospital admissions are well established, few previous studies have reported on primary care clinical and prescribing data. We assessed the associations of short and long-term pollutant exposures with General Practitioner respiratory consultations and inhaler prescriptions. Methods Daily primary care data, for 2009–2013, were obtained from Lambeth DataNet (LDN), an anonymised dataset containing coded data from all patients (1.2 million) registered at general practices in Lambeth, an inner-city south London borough. Counts of respiratory consultations and inhaler prescriptions by day and Lower Super Output Area (LSOA) of residence were constructed. We developed models for predicting daily PM2.5, PM10, NO2 and O3 per LSOA. We used spatio-temporal mixed effects zero inflated negative binomial models to investigate the simultaneous short- and long-term effects of exposure to pollutants on the number of events. Results The mean concentrations of NO2, PM10, PM2.5 and O3 over the study period were 50.7, 21.2, 15.6, and 49.9 μg/m3 respectively, with all pollutants except NO2 having much larger temporal rather than spatial variability. Following short-term exposure increases to PM10, NO2 and PM2.5 the number of consultations and inhaler prescriptions were found to increase, especially for PM10 exposure in children which was associated with increases in daily respiratory consultations of 3.4% and inhaler prescriptions of 0.8%, per PM10 interquartile range (IQR) increase. Associations further increased after adjustment for weekly average exposures, rising to 6.1 and 1.2%, respectively, for weekly average PM10 exposure. In contrast, a short-term increase in O3 exposure was associated with decreased number of respiratory consultations. No association was found between long-term exposures to PM10, PM2.5 and NO2 and number of respiratory consultations. Long-term exposure to NO2 was associated with an increase (8%) in preventer inhaler prescriptions only. Conclusions We found increases in the daily number of GP respiratory consultations and inhaler prescriptions following short-term increases in exposure to NO2, PM10 and PM2.5. These associations are more pronounced in children and persist for at least a week. The association with long term exposure to NO2 and preventer inhaler prescriptions indicates likely increased chronic respiratory morbidity.

scholarly journals Paleolithic Diet—Effect on the Health Status and Performance of Athletes?

Nutrients ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 1019
Author(s):  
Barbara Frączek ◽  
Aleksandra Pięta ◽  
Adrian Burda ◽  
Paulina Mazur-Kurach ◽  
Florentyna Tyrała
Keyword(s):  
Blood Pressure ◽  
Body Mass ◽  
Positive Impact ◽  
Model Assessment ◽  
Paleolithic Diet ◽  
Short Term ◽  
Positive Effects ◽  
Short And Long Term ◽  
The Impact

The aim of this meta-analysis was to review the impact of a Paleolithic diet (PD) on selected health indicators (body composition, lipid profile, blood pressure, and carbohydrate metabolism) in the short and long term of nutrition intervention in healthy and unhealthy adults. A systematic review of randomized controlled trials of 21 full-text original human studies was conducted. Both the PD and a variety of healthy diets (control diets (CDs)) caused reduction in anthropometric parameters, both in the short and long term. For many indicators, such as weight (body mass (BM)), body mass index (BMI), and waist circumference (WC), impact was stronger and especially found in the short term. All diets caused a decrease in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), albeit the impact of PD was stronger. Among long-term studies, only PD cased a decline in TC and LDL-C. Impact on blood pressure was observed mainly in the short term. PD caused a decrease in fasting plasma (fP) glucose, fP insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) and glycated hemoglobin (HbA1c) in the short run, contrary to CD. In the long term, only PD caused a decrease in fP glucose and fP insulin. Lower positive impact of PD on performance was observed in the group without exercise. Positive effects of the PD on health and the lack of experiments among professional athletes require longer-term interventions to determine the effect of the Paleo diet on athletic performance.

scholarly journals Induction of cell wall phenolic monomers as part of direct defense response in maize to pink stem borer (Sesamia inferens Walker) and non-insect interactions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Lakshmi Soujanya ◽  
J. C. Sekhar ◽  
C. V. Ratnavathi ◽  
Chikkappa G. Karjagi ◽  
E. Shobha ◽  
...  
Keyword(s):  
Induced Defense ◽  
Stem Borer ◽  
Defense Responses ◽  
Short Term ◽  
Mechanical Wounding ◽  
Leaf Tissues ◽  
Short And Long Term ◽  
Insect Interactions ◽  
Induced Defense Responses

AbstractPink stem borer (PSB) causes considerable yield losses to maize. Plant–insect interactions have significant implications for sustainable pest management. The present study demonstrated that PSB feeding, mechanical wounding, a combination of mechanical wounding and PSB regurgitation and exogenous application of methyl jasmonate have induced phenolic compound mediated defense responses both at short term (within 2 days of treatment) and long term (in 15 days of treatment) in leaf and stalk tissues of maize. The quantification of two major defense related phenolic compounds namely p-Coumaric acid (p-CA) and ferulic acid (FA) was carried out through ultra-fast liquid chromatography (UFLC) at 2 and 15 days after imposing the above treatments. The p-CA content induced in leaf tissues of maize genotypes were intrinsically higher when challenged by PSB attack at V3 and V6 stages in short- and long-term responses. Higher p-CA content was observed in stalk tissues upon wounding and regurgitation in short- and long-term responses at V3 and V6 stages. Significant accumulation of FA content was also observed in leaf tissues in response to PSB feeding at V3 stage in long-term response while at V6 stage it was observed both in short- and long-term responses. In stalk tissues, methyl jasmonate induced higher FA content in short-term response at V3 stage. However, at V6 stage PSB feeding induced FA accumulation in the short-term while, wounding and regurgitation treatment-induced defense responses in the long-term. In general, the resistant (DMRE 63, CM 500) and moderately resistant genotypes (WNZ ExoticPool) accumulated significantly higher contents of p-CA and FA content than susceptible ones (CM 202, BML 6) in most of the cases. The study indicates that phenolic mediated defense responses in maize are induced by PSB attack followed by wounding and regurgitation compared to the other induced treatments. Furthermore, the study confirmed that induced defense responses vary with plant genotype, stage of crop growth, plant tissue and short and long-term responses. The results of the study suggested that the Phenolic acids i.e. p-CA and FA may contribute to maize resistance mechanisms in the maize-PSB interaction system.

scholarly journals Short-Term Exuberance and Long-Term Stability: A Simultaneous Optimization of Stock Return Predictions for Short and Long Horizons

Mathematics ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 620
Author(s):  
Ioannis Kyriakou ◽  
Parastoo Mousavi ◽  
Jens Perch Nielsen ◽  
Michael Scholz
Keyword(s):  
Stock Returns ◽  
Simultaneous Optimization ◽  
Investment Risk ◽  
Short Term ◽  
Fundamental Interest ◽  
Long Term Stability ◽  
Risk Appetite ◽  
Short And Long Term ◽  
Excess Stock Returns

The fundamental interest of investors in econometric modeling for excess stock returns usually focuses either on short- or long-term predictions to individually reduce the investment risk. In this paper, we present a new and simple model that contemporaneously accounts for short- and long-term predictions. By combining the different horizons, we exploit the lower long-term variance to further reduce the short-term variance, which is susceptible to speculative exuberance. As a consequence, the long-term pension-saver avoids an over-conservative portfolio with implied potential upside reductions given their optimal risk appetite. Different combinations of short and long horizons as well as definitions of excess returns, for example, concerning the traditional short-term interest rate but also the inflation, are easily accommodated in our model.

scholarly journals Effect of short-term smoking & L-arginine on coronary endothelial function assessed by cardiac magnetic resonance cold pressor testing: a pilot study

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Andreas M. Weng ◽  
Herbert Köstler ◽  
Thorsten A. Bley ◽  
Christian O. Ritter
Keyword(s):  
Magnetic Resonance ◽  
Imaging Techniques ◽  
Cold Pressor Test ◽  
Cold Pressor ◽  
Short Term ◽  
Pressor Test ◽  
Coronary Vasomotion ◽  
Short And Long Term ◽  
Coronary Endothelium

Abstract Background The effect of smoking on coronary vasomotion has been investigated in the past with various imaging techniques in both short- and long-term smokers. Additionally, coronary vasomotion has been shown to be normalized in long-term smokers by L-Arginine acting as a substrate for NO synthase, revealing the coronary endothelium as the major site of abnormal vasomotor response. Aim of the prospective cohort study was to investigate coronary vasomotion of young healthy short-term smokers via magnetic resonance cold pressor test with and without the administration of L-Arginine and compare obtained results with the ones from nonsmokers. Methods Myocardial blood flow (MBF) was quantified with first-pass perfusion MRI on a 1.5 T scanner in healthy short-term smokers (N = 10, age: 25.0 ± 2.8 years, 5.0 ± 2.9 pack years) and nonsmokers (N = 10, age: 34.3 ± 13.6) both at rest and during cold pressor test (CPT). Smokers underwent an additional examination after administration of L-Arginine within a median of 7 days of the naïve examination. Results MBF at rest turned out to be 0.77 ± 0.30 (smokers with no L-Arginine; mean ± standard deviation), 0.66 ± 0.21 (smokers L-Arginine) and 0.84 ± 0.08 (nonsmokers). Values under CPT were 1.21 ± 0.42 (smokers no L-Arginine), 1.09 ± 0.35 (smokers L-Arginine) and 1.63 ± 0.33 (nonsmokers). In all groups, MBF was significantly increased under CPT compared to the corresponding rest examination (p < 0.05 in all cases). Additionally, MBF under CPT was significantly different between the smokers and the nonsmokers (p = 0.002). MBF at rest was significantly different between the smokers when L-Arginine was given and the nonsmokers (p = 0.035). Conclusion Short-term smokers showed a reduced response to cold both with and without the administration of L-Arginine. However, absolute MBF values under CPT were lower compared to nonsmokers independently of L-Arginine administration.

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