104 research outputs found
Evidence for long-term variability in the ultra high energy photon flux from Cygnus X-3
A time-correlation analysis of atmospheric Cerenkov pulses by a wide-angle photomultiplier system was previously shown to have present in it a nonrandom component which seemed associated with the Right Ascension (RA) range approx. 20+or-04h. A recent examination of multi-muon events recorded by a photon-decay detector shows a similar time-dependent effect, closely matching the previous results, supporting the suggestion that the effect is of cosmic origin. However, even though Cyg. X-3 lies well inside the region of peak intensity, it does not seem possible to ascribe to it the whole effect, for the implied photon flux appears too large to be reconciled to various gamma-ray measurements of Cyg. X-3. The original data were subjected to a phase-histogram analysis and it as found that only 2.5% of overall recorded data are compatible with a phase-dependent emission from Cyg. X-3. Assuming these events to be gamma rays yields a detected flux of (2.6 + or - 0.3) x 10 to the minus 12th power gamma cm -2s-1 above 5 x 10 to the 14th power eV. Comparing this value with more recent ultra high energy (UHE) photon data from the same source, it is suggested that the available data generally favor a long-term reduction in the Cyg. X-3 inferred luminosity ( 10 to the 13th power eV) by a factor of (1.8 + or - 0.3) per year
Periodic gamma-ray emissions from Geminga at or = 10(12) eV
Analysis of data from an atmospheric Cerenkov telescope indicated the periodic emission of gamma rays of energy 10 to the 12th power eV, at 60.25 second period, from 2CG 195+4. The gamma ray flux at 99% confidence level is estimated to be 9.5 x 10 to 12 photons/sq cm/s
Antioxidant and Antimicrobial Properties of the Essential Oil and Extracts of Zanthoxylum alatum
The essential oil obtained from the fresh leaves of Zanthoxylum alatum was analysed by gas chromatography/mass spectrometry (GC/MS). Fourteen components were identified, and linalool (30.58%), 2-decanone (20.85%), β-fenchol (9.43%), 2-tridecanone (8.86%), β-phellandrene (5.99%), Sabinene (4.82%), and α-pinene (4.11%) were the main components. The EO and methanolic extract of Z. alatum exhibited potent antifungal activity against Alternaria alternata, Alternaria brassicae, and Curvularia lunata. The EO also showed significant antibacterial activity against Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus, and Escherichia coli. Further, antimicrobial constituents of the EO were isolated by bioautography and preparative thin layer chromatography (PTLC) and identified as β-fenchol and linalool using GC/MS analysis. In addition to this, the free radical scavenging activity and antioxidant potential of EO and methanolic extract/fractions of Z. alatum were also investigated using in vitro assays including scavenging ability against DPPH•, reducing power and chelating ability on Fe2+ ions. Our results demonstrate that Z. alatum could be used as a resource of antioxidant and antimicrobial compounds which may find applications in food and pesticide industries
Solid-phase synthesis and crystal structure of 5(3-nitrophenyl)-3,7-diphenyl-4H,6H-1,2-diazepine
Scaling in the Bombay Stock Exchange Index
In this paper we study BSE Index financial time series for fractal and
multifractal behaviour. We show that Bombay stock Exchange (BSE)Index time
series is mono-fractal and can be represented by a fractional Brownian motion.Comment: 11 pages,3 figure
Interações químico-fisiolóficas entre acidificantes, probióticos, enzimas e lisofosfolipídios na digestão de leitões
Causes, consequences and biomarkers of stress in swine: an update
BACKGROUND: In recent decades there has been a growing concern about animal stress on intensive pig farms due to the undesirable consequences that stress produces in the normal physiology of pigs and its effects on their welfare and general productive performance. This review analyses the most important types of stress (social, environmental, metabolic, immunological and due to human handling), and their biological consequences for pigs. The physio-pathological changes associated with stress are described, as well as the negative effects of stress on pig production. In addition an update of the different biomarkers used for the evaluation of stress is provided. These biomarkers can be classified into four groups according to the physiological system or axis evaluated: sympathetic nervous system, hypothalamic-pituitary-adrenal axis, hypothalamic-pituitary-gonadal axis and immune system. CONCLUSIONS: Stress it is a process with multifactorial causes and produces an organic response that generates negative effects on animal health and production. Ideally, a panel of various biomarkers should be used to assess and evaluate the stress resulting from diverse causes and the different physiological systems involved in the stress response. We hope that this review will increase the understanding of the stress process, contribute to a better control and reduction of potential stressful stimuli in pigs and, finally, encourage future studies and developments to better monitor, detect and manage stress on pig farms
Microwave absorption studies of BaCoTi ferrite composites
422-425<span style="font-size:
15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">A
ferrite series of the composition BaFe12-2x,CoxTixO19,
wherein <span style="font-size:16.0pt;mso-bidi-font-size:9.0pt;
font-family:" times="" new="" roman","serif""="">x <span style="font-size:
15.0pt;mso-bidi-font-size:8.0pt;font-family:" times="" new="" roman","serif""="">varies
from 0.0 to 0.9 in steps of 0.2, has been prepared by the standard ceramic technique.
The microwave absorption studies of ferrite-polymer composites with different till-factors
have been made in the frequency range from 8.6- 12.4 GHz. A maximum return loss
of 14.7 dB has been obtained for composites with x
<span style="font-size:15.0pt;mso-bidi-font-size:8.0pt;font-family:
" times="" new="" roman","serif""="">equal 0.3 and absorber thickness of 4.0 mm at 9.2
GHz. The dependence of matching frequency on composition is apparent for this
thickness. The maximum values of dc resistivity and the Curie temperature have
been found to be 234.8 kQ and 469°C respectively. These values correspond to
the same composition for which the return loss is the maximum. A dependence of
return loss on complex dielectric constant and permeability has been investigated
in the X-band.
</span
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