929 research outputs found
Observation of R-Band Variability of L Dwarfs
We report, for the first time, photometric variability of L dwarfs in
band. Out of three L1 dwarfs (2MASS 1300+19, 2MASS 1439+19, and 2MASS 1658+70)
observed, we have detected R band variability in 2MASS 1300+19 and 2MASS
1439+19. The objects exhibit variability of amplitude ranging from 0.01 mag to
0.02 mag. Object 2MASS 1658+70, turns out to be non-variable in both and
band. However, more observations are needed to infer its variability. No
periodic behaviour in the variability is found from the two L1 dwarfs that are
variable. All the three L1 dwarfs have either negligible or no
activity. In the absence of any direct evidence for the presence of
sufficiently strong magnetic field, the detection of polarization at the
optical favors the presence of dust in the atmosphere of L dwarfs. We suggest
that the observed band photometric variability is most likely due to
atmospheric dust activity.Comment: 13 pages (latex, aastex style) including 3 eps figures. Accepted for
publication in The Astrophysical Journal Letter
Night sky at the Indian Astronomical Observatory during 2000-2008
We present an analysis of the optical night sky brightness and extinction
coefficient measurements in UBVRI at the Indian Astronomical Observatory (IAO),
Hanle, during the period 2003-2008. They are obtained from an analysis of CCD
images acquired at the 2 m Himalayan Chandra Telescope at IAO. Night sky
brightness was estimated using 210 HFOSC images obtained on 47 nights and
covering the declining phase of solar activity cycle-23. The zenith corrected
values of the moonless night sky brightness in mag/square arcsecs are 22.14(U),
22.42(B), 21.28(V), 20.54(R) and 18.86(I) band. This shows that IAO is a dark
site for optical observations. No clear dependency of sky brightness with solar
activity is found. Extinction values at IAO are derived from an analysis of
1325 images over 58 nights. They are found to be 0.36 in U-band, 0.21 in
B-band, 0.12 in V-band, 0.09 in R-band and 0.05 in I-band. On average,
extinction during the summer months is slightly larger than that during the
winter months. No clear evidence for a correlation between extinction in all
bands and the average night time wind speed is found. Also presented here is
the low resolution moonless optical night sky spectrum for IAO covering the
wavelength range 3000-9300 \AA. Hanle region thus has the required
characteristics of a good astronomical site in terms of night sky brightness
and extinction, and could be a natural candidate site for any future large
aperture Indian optical-infrared telescope(s).Comment: 18 pages, 7 figures, uses basi.cls, accepted for publication in
Bulletin of the Astronomical Society of Indi
Surgical Management of a Rare Case of Congenital DoubleUpper Lip
Congenital double lip is a rare developmental anomaly which usually involves the upper lip. It may occur in isolation or as a part of Ascher's syndrome. The occurrence of double lip may result in facial deformity especially when patient attempts to talk, smile, or even try to show the teeth. It affects esthetics and also interferes with speech and mastication. Although surgery may be undertaken to facilitate speech and mastication, majority of cases are operated for cosmetic reasons. A case of congenital double upper lip which was surgically treated for cosmetic reason is reported
An unusual very low-mass high-amplitude pre-main sequence periodic variable
We have investigated the nature of the variability of CHS7797, an unusual
periodic variable in the Orion Nebula Cluster. An extensive I-band photometric
data set of CHS7797 was compiled between 2004-2010 using various telescopes.
Further optical data have been collected in R and z' bands. In addition,
simultaneous observations of the ONC region including CHS7797 were performed in
the I, J, Ks and IRAC [3.6] and [4.5] bands over a time interval of about 40d.
CHS7797 shows an unusual large-amplitude variation of about 1.7 mag in the R,
I, and z' bands with a period 17.786. The amplitude of the brightness
modulation decreases only slightly at longer wavelengths. The star is faint
during 2/3 of the period and the shape of the phased light-curves for seven
different observing seasons shows minor changes and small-amplitude variations.
Interestingly, there are no significant colour-flux correlations for
wavelengths smaller than 2microns, while the object becomes redder when fainter
at longer wavelengths. CHS7797 has a spectral type of M6 and an estimated mass
between 0.04-0.1Msun. The analysis of the data suggests that the periodic
variability of CHS7797 is most probably caused by an orbital motion.
Variability as a result of rotational brightness modulation by spots is
excluded by the lack of any color-brightness correlation in the optical. The
latter indicates that CHS7797 is most probably occulted by circumstellar matter
in which grains have grown from typical 0.1 microns to 1-2 micron sizes. We
discuss two possible scenarios in which CHS7797 is periodically eclipsed by
structures in a disc, namely that CHS7797 is a single object with a
circumstellar disc, or that CHS7797 is a binary system, similar to KH15D, in
which an inclined circumbinary disc is responsible of the variability. Possible
reasons for the typical 0.3mag variations in I-band at a given phase are
discussed.Comment: 11 pages, 9 figures, accepted for publication A&
Effect of dual-purpose summer legumes and zinc fertilization on system productivity, economics and nutrient use-efficiencies of rice (Oryza sativa) – wheat (Triticum aestivum) cropping system
A field experiment was conducted during 2007-09 at the research farm of IARI, New Delhi, India; to study the effects of dual-purpose summer legumes and zinc fertilization in aromatic hybrid rice (Oryza sativa L.)– wheat (Triticum aestivum L.) cropping system. The higher system productivity, N and Zn uptake, nutrient-use efficiencies, net return and B:C ratio were recorded in cowpea [Vigna unguiculata (L.) Walp.] or mungbean (Vigna radiata L.) residue incorporated plots. The N balance was negative (-) in all treatments but it was least negative (-) in cowpea among summer treatments followed by mungbean. The highest N and Zn uptake, system productivity in terms of grain yield, i.e. 12.32 and 12.71 tonnes/ha was observed with application of 2.0% ZEU (ZnSO4.7H2O). Among the Zn fertilization treatments the lowest negative (-) balance of N was recorded with control (only N), i.e. -36.92 kg/ha in 2007-08 however in 2008-09 it was recorded with coating material coated urea, i.e. -39.54 kg N/ha over rest of the Zn treatments. The application of 5.0 kg Zn/ha (ZnO) gave the highest (2 696 and 2 601 g/ha during 2007-08 and 2008-09, respectively) positive Zn balance under rice-wheat cropping system. Partial factor productivity, agronomic efficiency, apparent recovery and physiological efficiency of applied N and Zn in rice-wheat cropping system were increased with Zn-enriched urea. The agronomic efficiency of N with 2.0% ZEU (ZnSO4.7H2O) increased by 49.7% and the N recovery efficiency in grain increased up to 57.6% over normal practice of prilled urea application. With the application of 2.0% ZEU (ZnSO4.7H2O) the agronomic efficiency of Zn increased in the range of 54 to 160% while Zn apparent recovery (%) in grain increased from 70 to 318% over 2.0% ZEU (ZnO) and 5.0 kg Zn/ha (ZnO), respectively. The dual-purpose summer legume incorporation in rice-wheat system gave higher net returns by 29 to 34% in 2007-08 and 42 to 45% during 2008-09 over summer fallow with B:C ratio up to 3.01. The application of 2.0% ZEU (ZnSO4.7H2O) gave the highest B:C ratio of 3.02 and increased net returns of aromatic-hybrid rice-wheat system by 11.6 to 12.2% over prilled urea application
Orbital and physical parameters of eclipsing binaries from the ASAS catalogue - IV. A 0.61 + 0.45 M_sun binary in a multiple system
We present the orbital and physical parameters of a newly discovered low-mass
detached eclipsing binary from the All-Sky Automated Survey (ASAS) database:
ASAS J011328-3821.1 A - a member of a visual binary system with the secondary
component separated by about 1.4 seconds of arc. The radial velocities were
calculated from the high-resolution spectra obtained with the 1.9-m
Radcliffe/GIRAFFE, 3.9-m AAT/UCLES and 3.0-m Shane/HamSpec
telescopes/spectrographs on the basis of the TODCOR technique and positions of
H_alpha emission lines. For the analysis we used V and I band photometry
obtained with the 1.0-m Elizabeth and robotic 0.41-m PROMPT telescopes,
supplemented with the publicly available ASAS light curve of the system.
We found that ASAS J011328-3821.1 A is composed of two late-type dwarfs
having masses of M_1 = 0.612 +/- 0.030 M_sun, M_2 = 0.445 +/- 0.019 M_sun and
radii of R_1 = 0.596 +/- 0.020 R_sun, R_2 = 0.445 +/- 0.024 R_sun, both show a
substantial level of activity, which manifests in strong H_alpha and H_beta
emission and the presence of cool spots. The influence of the third light on
the eclipsing pair properties was also evaluated and the photometric properties
of the component B were derived. Comparison with several popular stellar
evolution models shows that the system is on its main sequence evolution stage
and probably is more metal rich than the Sun. We also found several clues which
suggest that the component B itself is a binary composed of two nearly
identical ~0.5 M_sun stars.Comment: 12 pages, 7 figures, 7 tables, to appear in MNRA
Omega-3 Fatty Acid and Iron Supplementation Alone, but Not in Combination, Lower Inflammation and Anemia of Infection in Mycobacterium tuberculosis-Infected Mice
Progressive inflammation and anemia are common in tuberculosis (TB) and linked to poor clinical outcomes. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have inflammation-resolving properties, whereas iron supplementation in TB may have limited efficacy and enhance bacterial growth. We investigated effects of iron and EPA/DHA supplementation, alone and in combination, on inflammation, anemia, iron status markers and clinical outcomes in Mycobacterium tuberculosis-infected C3HeB/FeJ mice. One week post-infection, mice received the AIN-93 diet without (control) or with supplemental iron (Fe), EPA/DHA, or Fe+EPA/DHA for 3 weeks. Mice supplemented with Fe or EPA/DHA had lower soluble transferrin receptor, ferritin and hepcidin than controls, but these effects were attenuated in Fe+EPA/DHA mice. EPA/DHA increased inflammation-resolving lipid mediators and lowered lung IL-1α, IFN-γ, plasma IL-1β, and TNF-α. Fe lowered lung IL-1α, IL-1β, plasma IL-1β, TNF-α, and IL-6. However, the cytokine-lowering effects in the lungs were attenuated with Fe+EPA/DHA. Mice supplemented with EPA/DHA had lower lung bacterial loads than controls, but this effect was attenuated in Fe+EPA/DHA mice. Thus, individually, post-infection EPA/DHA and iron supplementation lowered systemic and lung inflammation and mitigated anemia of infection in TB, but not when combined. EPA/DHA also enhanced bactericidal effects and could support inflammation resolution and management of anemia
Adjunct n-3 Long-Chain Polyunsaturated Fatty Acid Treatment in Tuberculosis Reduces Inflammation and Improves Anemia of Infection More in C3HeB/FeJ Mice With Low n-3 Fatty Acid Status Than Sufficient n-3 Fatty Acid Status
Populations at risk for tuberculosis (TB) may have a low n-3 polyunsaturated fatty acid
(PUFA) status. Our research previously showed that post-infection supplementation of
n-3 long-chain PUFA (LCPUFA) in TB without TB medication was beneficial in n-3
PUFA sufficient but not in low-status C3HeB/FeJ mice. In this study, we investigated
the effect of n-3 LCPUFA adjunct to TB medication in TB mice with a low compared
to a sufficient n-3 PUFA status. Mice were conditioned on an n-3 PUFA-deficient (n-
3FAD) or n-3 PUFA-sufficient (n-3FAS) diet for 6 weeks before TB infection. Postinfection
at 2 weeks, both groups were switched to an n-3 LCPUFA [eicosapentaenoic
acid (EPA)/docosahexaenoic acid (DHA)] supplemented diet and euthanized at 4- and
14- days post-treatment. Iron and anemia status, bacterial loads, lung pathology, lung
cytokines/chemokines, and lung lipid mediators were measured. Following 14 days of
treatment, hemoglobin (Hb) was higher in the n-3FAD than the untreated n-3FAS group
(p = 0.022), whereas the n-3FAS (drug) treated control and n-3FAS groups were not. Proinflammatory
lung cytokines; interleukin-6 (IL-6) (p = 0.011), IL-1a (p = 0.039), MCP1
(p = 0.003), MIP1- a (p = 0.043), and RANTES (p = 0.034); were lower, and the antiinflammatory
cytokine IL-4 (p=0.002) and growth factor GMCSF (p=0.007) were higher
in the n-3FAD compared with the n-3FAS mice after 14 days. These results suggest that
n-3 LCPUFA therapy in TB-infected mice, in combination with TB medication, may
improve anemia of infection more in low n-3 fatty acid status than sufficient status mice.
Furthermore, the low n-3 fatty acid status TB mice supplemented with n-3 LCPUFA
showed comparatively lower cytokine-mediated inflammation despite presenting with
lower pro-resolving lipid mediators
Effect of seed moisture content and storage temperature on seed longevity of hemp (Cannabis sativa)
Hemp (Cannabis sativa L.) is one of the earliest domesticated plants grown for its protein and oil rich seed, fiber and psychoactive substances and it is one of the earliest known medicinal plants in human history. Studies were conducted on seed germinability (germination test) and viability (topographical tetrazoliun chloride test) in three seed lots to determine the seed quality. Studies conducted on effect of five seed moisture contents (5, 7, 8, 10 and 12 % on fresh weight basis), three storage temperature (ambient, 15°C and -20°C) and eight storage periods (0, 3, 6, 9, 12, 18, 24 and 36 months) on seed longevity revealed that the critical moisture content (moisture content required in seeds for retaining initial germination after storage of seeds up to 36 months) of seeds for ambient storage condition of Delhi was 5 %, which increased to 7 % in 15°C and 12 % at -20°C storage temperature. The seeds are desiccation as well as chilling tolerant, therefore, exhibit orthodox storage behavior and are ideal for ex-situ conservation of seeds in seed/gene banks
Precision nutrient and conservation agriculture practices for enhancing productivity, profitability, nutrient-use efficiencies and soil nutrient status of maize (Zea mays) hybrids
A field experiment was conducted at New Delhi during kharif season to study the effect of precision nutrient and conservation agriculture practices for enhancing productivity, profitability, nutrient-use efficiencies and soil nutrient status of maize (Zea mays L) hybrids. Using nutrient expert system based site-specific nutrient management (SSNM) practices higher dose of K and N while lower dose of P were estimated for hybrid maize over recommended dose of fertilizers (RDF). Data of the previous crop, target yield, residue management and soil nutrient status were entered in the nutrient expert system. The significant interaction of SSNM and hybrids showed that hybrid PMH 3 along with site specific nutrient management (SSNM) produced significantly higher grain yield under conservation agriculture. The SSNM practice gave 14.7% higher grain yield (5 491 kg/ha) over RDF (4 182 kg/ha). Significantly higher gross return, net return (Rupees 41 137) and B:C ratio (1.57) was obtained with SSNM and the net returns of the maize were improved by rupees 7 856/ha by SSNM over RDF. Amongst genotypes, PMH 3 produced significantly higher gross, net return and B:C ratio over HQPM 1, however, it remained at par with PMH 1, S 6217 and CMH 08-292. Significantly higher partial factor productivity of applied N, P and K was obtained with 50% RDF while it remained at par for applied P by SSNM. Significantly highest agronomic efficiency of applied N and P was obtained with SSNM while for applied K it was significantly highest with 50% RDF. Initially before crop sowing, significantly highest organic carbon in soil was in 100% RDF plots. However, significantly higher organic carbon build up was obtained with SSNM which remained at par with 100% RDF, after crop harvest. In SSNM plots, significantly higher ammonical nitrogen and potassium was observed after maize harvest
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