436 research outputs found

    Resolving the chemical substructure of Orion-KL

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    The Kleinmann-Low nebula in Orion (Orion-KL) is the nearest example of a high-mass star-forming environment. For the first time, we complemented 1.3 mm Submillimeter Array (SMA) interferometric line survey with IRAM 30 m single-dish observations of the Orion-KL region. Covering a 4 GHz bandwidth in total, this survey contains over 160 emission lines from 20 species (25 isotopologues), including 11 complex organic molecules (COMs). At a spatial resolution of 1200 AU, the continuum substructures are resolved. Extracting the spectra from individual substructures and providing the intensity-integrated distribution map for each species, we studied the small-scale chemical variations in this region. Our main results are: (1) We identify lines from the low-abundance COMs CH3COCH3 and CH3CH2OH, as well as tentatively detect CH3CHO and long carbon-chains C6H and HC7N. (2) We find that while most COMs are segregated by type, peaking either towards the hot core (e.g., N-bearing species) or the compact ridge (e.g., O-bearing species like HCOOCH3 and CH3OCH3), while the distributions of others do not follow this segregated structure (e.g., CH3CH2OH, CH3OH, CH3COCH3). (3) We find a second velocity component of HNCO, SO2, 34SO2, and SO lines, which may be associated with a strong shock event in the low-velocity outflow. (4) Temperatures and molecular abundances show large gradients between central condensations and the outflow regions, illustrating a transition between hot molecular core and shock-chemistry dominated regimes. Our observations of spatially resolved chemical variations in Orion-KL provide the nearest reference source for hot molecular core and outflow chemistry, which will be an important example for interpreting the chemistry of more distant HMSFRs.Comment: 51 pages, 17 figures, accepted on 12 March 2015 Dashed lines in Figure 10 of the published paper was missin

    Phytopharmacotherapeutic and Antimicrobial Attributes of Bitter Apple (Citrullus colocynthis) - A Review

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    Emergence of drug-resistant microorganisms over the past few decades has resulted in the search for bioactive compounds potent against these microorganisms. Phytochemicals derived from plants have shown positive curative properties and can be extracted from any part of the plant such as the roots, stem or flower. Bitter apple (Citrullus colocynthis) has been used traditionally for the treatment of infectious diseases and this has stimulated pharmacological interest in the active ingredients responsible for its medicinal properties. The plant also possesses several biological and pharmacological activities including anti-inflammatory, antidiabetic, antimicrobial, anticancer, and antioxidant. This review discussed the phytochemicals present in C. colocynthis, their mode of action and their antimicrobial attributes

    Phytopharmacotherapeutic and Antimicrobial Attributes of Bitter Apple (Citrullus colocynthis) - A Review

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    Emergence of drug-resistant microorganisms over the past few decades has resulted in the search for bioactive compounds potent against these microorganisms. Phytochemicals derived from plants have shown positive curative properties and can be extracted from any part of the plant such as the roots, stem or flower. Bitter apple (Citrullus colocynthis) has been used traditionally for the treatment of infectious diseases and this has stimulated pharmacological interest in the active ingredients responsible for its medicinal properties. The plant also possesses several biological and pharmacological activities including anti-inflammatory, antidiabetic, antimicrobial, anticancer, and antioxidant. This review discussed the phytochemicals present in C. colocynthis, their mode of action and their antimicrobial attributes

    Analysis of Groundwater Pollution from an Unlined Constructed Wetland Sludge Drying Bed

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    Sludge drying beds (SBDs) are part of wastewater treatment processes where dewatering and reduction of water content from the substrate sludge take place to enhance caking and thus facilitate handling and disposal. In this study, the effect of the operation of an unlined drying bed of a constructed wetland for domestic wastewater treatment on the adjourning groundwater was investigated. Experimental boreholes for water quality monitoring were constructed downstream of the SBD prior to its operation. Preliminary investigations of the quality of water in the boreholes were carried out before the operation of the SBD. The concentration levels of pH, Conductivity, Total Dissolved Solids, Colour, Mn, Fe, SO4, NO3, Total Coliform and e-coli were used to empirically and statistically determine the level of pollution of the ground water during the operation of the SDB. The 2-way ANOVA at (=0.05) showed that the operation of the SBD had statistically significant impact on the quality of the groundwater on all the observed parameters. For the parameters observed, p<0.05 (p=0.00 for the averages of pH, EC, TDS, Turbidity, Colour, Mn+2, Fe+2, SO4 and NO3), while p=0.0028 and 0.0018 for the averages of Total coliform and E.coli respectively in all the boreholes. The distances from the discharge point of the SDB were at 15m, 20m, 25m, 30m, 35m, 40m and 50m for boreholes 1, 2, 3, 4, 5, 6 and 7 respectively. Also, comparison of the means of the quality parameters with the allowable limits set by the Nigerian National Environmental Surface and Groundwater Quality Control Regulations (NSGQCR) indicated that the operation of the SBD rendered the quality of the groundwater unacceptable

    A line confusion-limited millimeter survey of Orion KL. III. Sulfur oxide species

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    We present a study of the sulfur-bearing species detected in a line confusion-limited survey towards Orion KL performed with the IRAM 30m telescope in the range 80-281 GHz. The study is part of an analysis of the line survey divided into families of molecules. Our aim is to derive accurate physical conditions and molecular abundances in the different components of Orion KL from observed SO and SO2 lines. First we assumed LTE conditions obtain rotational temperatures. We then used a radiative transfer model, assuming either LVG or LTE excitation to derive column densities of these molecules in the different components of Orion KL. We have detected 68 lines of SO, 34SO, 33SO, and S18O and 653 lines of SO2, 34SO2, 33SO2, SO18O and SO2 v2=1. We provide column densities for all of them and also upper limits for the column densities of S17O, 36SO, 34S18O, SO17O and 34SO2 v2=1 and for several undetected sulfur-bearing species. In addition, we present 2'x2' maps around Orion IRc2 of SO2 transitions with energies from 19 to 131 K and also maps with four transitions of SO, 34SO and 34SO2. We observe an elongation of the gas along the NE-SW direction. An unexpected emission peak appears at 20.5 km/s in most lines of SO and SO2. A study of the spatial distribution of this emission feature shows that it is a new component ~5" in diameter, which lies ~4" west of IRc2. We suggest the emission from this feature is related to shocks associated to the BN object. The highest column densities for SO and SO2 are found in the high-velocity plateau (a region dominated by shocks) and in the hot core. These values are up to three orders of magnitude higher than the results for the ridge components. We also find high column densities for their isotopologues in both components. Therefore, we conclude that SO and SO2 are good tracers, not only of regions affected by shocks, but also of regions with warm dense gas.Comment: Paper (ref AA/2013/21285) accepted for publication by A&A. 52 Pages, 26 figures, 13 table

    Extended warm gas in Orion KL as probed by methyl cyanide

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    In order to study the temperature distribution of the extended gas within the Orion Kleinmann-Low nebula, we have mapped the emission by methyl cyanide (CH3CN) in its J=6_K-5_K, J=12_K-11_K, J=13_K-12_K, and J=14_K-13_K transitions at an average angular resolution of ~10 arcsec (22 arcsec for the 6_K-5_K lines), as part of a new 2D line survey of this region using the IRAM 30m telescope. These fully sampled maps show extended emission from warm gas to the northeast of IRc2 and the distinct kinematic signatures of the hot core and compact ridge source components. We have constructed population diagrams for the four sets of K-ladder emission lines at each position in the maps and have derived rotational excitation temperatures and total beam-averaged column densities from the fitted slopes. In addition, we have fitted LVG model spectra to the observations to determine best-fit physical parameters at each map position, yielding the distribution of kinetic temperatures across the region. The resulting temperature maps reveal a region of hot (T > 350 K) material surrounding the northeastern edge of the hot core, whereas the column density distribution is more uniform and peaks near the position of IRc2. We attribute this region of hot gas to shock heating caused by the impact of outflowing material from active star formation in the region, as indicated by the presence of broad CH3CN lines. This scenario is consistent with predictions from C-shock chemical models that suggest that gas-phase methyl cyanide survives in the post-shock gas and can be somewhat enhanced due to sputtering of grain mantles in the passing shock front.Comment: 24 pages, 20 figures, accepted for publication in A&

    Patogenisitas Beberapa Isolat Cendawan Entomopatogen Metarhizium Spp. Terhadap Telur Spodoptera Litura Fabricius (Lepidoptera: Noctuidae)

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    Metarhizium spp. is one of the entomopathogenic fungus that can be used to control Spodoptera litura. The purpose of this research was to study the pathogenicity of Metarhizium spp. to Spodoptera litura eggs. The isolates were collected from rhizosphere of different crops i.e., cabbage, onion, leek and Chili. The results showed that there was effect of all isolates on egg mortality. Mortality of S. litura eggs depend on the fungal isolates, ranged between 19.79%-75.70%. First instar larvae was also died 3 days after eclosion. The maximum mortality of first instar larvae was 58.65%. At a concentration of 108 conidia/ml, isolate Mt-kb had the highest virulence which caused higher mortality of eggs and first instar larvae

    Scientific Advancement in Contemporary Society: The Interface between Technology, Science and Law

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    This article is premised on the relation of technology and applied sciences with law. The three subjects are not only interwoven but cannot be protected and regulated without the viable use of law. The unprecedented advancement ofscientific innovations has far-reaching implication in virtually all ramifications of human endeavour. Technology is an invention created using science, which needs to be sustained by prudent management and law. The research goal is to narrow down a middle ground where all these independent fields can meet and share a symbiotic relationship without stifling each other. The research seeks to ascertain the knowledge and perception of selected university students of Nigeria and India, about Science, Law and Technology. The authors adopted the doctrinal and empirical research methodology coupled with the use of cases and legislations as source of information. The research revealed that majority of the participants has knowledge about the co-existence and impact of Science, Technology and Law in the society. However, the attitude and perception of the participants constitute a fundamental influence on the degree to which technological orientations occur during learning process. Also, 85% of 200 participants agreed that there is need for frequent education and legislation as science and technology evolves in the society. Hence, this article recommends the implementation and frequent modifications of law to continually protect, encourage and ensure the societal sustainability of ethical standards

    The hot core towards the intermediate mass protostar NGC7129 FIRS 2: Chemical similarities with Orion KL

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    NGC 7129 FIRS 2 (hereafter FIRS 2) is an intermediate-mass (2 to 8 Msun) protostar located at a distance of 1250 pc. High spatial resolution observations are required to resolve the hot core at its center. We present a molecular survey from 218200 MHz to 221800 MHz carried out with the IRAM Plateau de Bure Interferometer. These observations were complemented with a long integration single-dish spectrum taken with the IRAM 30m telescope. We used a Local Thermodynamic Equilibrium (LTE) single temperature code to model the whole dataset. The interferometric spectrum is crowded with a total of ~300 lines from which a few dozens remain unidentified yet. The spectrum has been modeled with a total of 20 species and their isomers, isotopologues and deuterated compounds. Complex molecules like methyl formate (CH3OCHO), ethanol (CH3CH2OH), glycolaldehyde (CH2OHCHO), acetone (CH3COCH3), dimethyl ether (CH3OCH3), ethyl cyanide (CH3CH2CN) and the aGg' conformer of ethylene glycol (aGg'-(CH2OH)_2) are among the detected species. The detection of vibrationally excited lines of CH3CN, CH3OCHO, CH3OH, OCS, HC3N and CH3CHO proves the existence of gas and dust at high temperatures. In fact, the gas kinetic temperature estimated from the vibrational lines of CH3CN, ~405 K, is similar to that measured in massive hot cores. Our data allow an extensive comparison of the chemistry in FIRS~2 and the Orion hot core. We find a quite similar chemistry in FIRS 2 and Orion. Most of the studied fractional molecular abundances agree within a factor of 5. Larger differences are only found for the deuterated compounds D2CO and CH2DOH and a few molecules (CH3CH2CN, SO2, HNCO and CH3CHO). Since the physical conditions are similar in both hot cores, only different initial conditions (warmer pre-collapse phase in the case of Orion) and/or different crossing time of the gas in the hot core can explain this behavior.Comment: 30 pages, 9 figure

    A combined IRAM and Herschel/HIFI study of cyano(di)acetylene in Orion KL: tentative detection of DC3N

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    We present a study of cyanoacetylene (HC3N) and cyanodiacetylene (HC5N) in Orion KL, through observations from two line surveys performed with the IRAM 30m telescope and the HIFI instrument on board the Herschel telescope. The frequency ranges covered are 80-280 GHz and 480-1906 GHz. We model the observed lines of HC3N, HC5N, their isotopologues (including DC3N), and vibrational modes, using a non-LTE radiative transfer code. To investigate the chemical origin of HC3N and DC3N in Orion KL, we use a time-dependent chemical model. We detect 40 lines of the ground state of HC3N and 68 lines of its 13C isotopologues. We also detect 297 lines of six vibrational modes of this molecule (nu_7, 2nu_7, 3nu_7, nu_6, nu_5, and nu_6+nu_7) and 35 rotational lines of the ground state of HC5N. We report the first tentative detection of DC3N in a giant molecular cloud with a DC3N/HC3N abundance ratio of 0.015. We provide column densities and isotopic and molecular abundances. We also perform a 2x2" map around Orion IRc2 and we present maps of HC3N lines and maps of lines of the HC3N vibrational modes nu_6 and nu_7. In addition, a comparison of our results for HC3N with those in other clouds allows us to derive correlations between the column density, the FWHM, the mass, and the luminosity of the clouds. The high column densities of HC3N obtained in the hot core, make this molecule an excellent tracer of hot and dense gas. In addition, the large frequency range covered reveals the need to consider a temperature and density gradient in the hot core in order to obtain better line fits. The high D/H ratio (comparable to that obtained in cold clouds) that we derive suggests a deuterium enrichment. Our chemical models indicate that the possible deuterated HC3N present in Orion KL is formed during the gas-phase. This fact provides new hints concerning the processes leading to deuteration.Comment: 50 pages, 33 figures, 13 tables. Accepted for publication in A&
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