| 1. |
- Riley, M A, et al.
(författare)
-
Beyond band termination in Er-157 and the search for wobbling excitations in strongly deformed Hf-174
- 2005
-
Ingår i: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. 1735-1740
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin terminating bands in heavy nuclei were first identified in nuclei around Er-158(90). While examples of special terminating states have been identified in a number of erbium isotopes, almost nothing is known about the states lying beyond band termination. In the present work the high-spin structure of Er-157 has been studied using the Gammasphere spectrometer. The subject of triaxial superdeformation and 'wobbling' modes in Lu nuclei has rightly attracted a great deal of attention. Very recently, four strongly or superdeformed (SD) sequences have been observed in Hf-174 and ultimate cranker calculations predict, such structures may have significant triaxial deformation. We have performed two experiments in an attempt to verify the possible triaxial nature of these bands. A lifetime measurement was performed to confirm the large (and similar) deformation of the bands. In addition, a high-statistics, thin-target experiment was run to search for linking transitions between the SD bands and possible wobbling modes.
|
|
| 2. |
- Riley, M. A., et al.
(författare)
-
Observation of states beyond band termination in Er-156,Er-157,Er-158 and strongly deformed structures in Hf-173,Hf-174,Hf-175
- 2006
-
Ingår i: Physica Scripta. - 0031-8949. ; T125, s. 123-126
-
Tidskriftsartikel (refereegranskat)abstract
- High-spin terminating bands in heavy nuclei were first identified in nuclei around Er-158(90). While examples of terminating states have been identified in a number of erbium isotopes, almost nothing is known about the states lying beyond band termination. In the present work, the high-spin structure of Er-156,Er-157,Er-158 has been studied using the Gammasphere spectrometer. The subject of triaxial superdeformation and 'wobbling' modes in Lu nuclei has rightly attracted a great deal of attention. Very recently four strongly or superdeformed (SD) sequences have been observed in Hf-174, and cranking calculations using the Ultimate Cranker code predict that such structures may have significant triaxial deformation. We have performed two experiments in an attempt to verify the possible triaxial nature of these bands. A lifetime measurement was performed to confirm the large (and similar) deformation of the bands. In addition, a high-statistics, thin-target experiment took place to search for linking transitions between the SD bands, possible wobbling modes, and new SD band structures.
|
|
| 3. |
- Chanda, Somen, et al.
(författare)
-
Seven-quasiparticle bands in Ce-139
- 2009
-
Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 79:5
-
Tidskriftsartikel (refereegranskat)abstract
- The high spin states in the Ce-139 nucleus have been studied by in-beam gamma-spectroscopic techniques using the reaction Te-130(C-12,3n)Ce-139 at E-beam=65 MeV. A gamma detector array, consisting of five Compton-suppressed Clover detectors was used for coincidence measurements. 15 new levels have been proposed and 28 new gamma transitions have been assigned to Ce-139 on the basis of gamma gamma coincidence data. The level scheme of Ce-139 has been extended above the known 70 ns 19/2 isomer up to similar to 6.1 MeV in excitation energy and 35/2h in spin. The spin-parity assignments for most of the newly proposed levels have been made using the deduced Directional Correlation from Oriented states of nuclei (DCO ratio) and the Polarization Directional Correlation from Oriented states (PDCO ratio) for the de-exciting transitions. The observed level structure has been compared with a large basis shell model calculation and also with the predictions from cranked Nilsson-Strutinsky (CNS) calculations. A general consistency has been observed between these two different theoretical approaches.
|
|
| 4. |
- Nriagu, J. O., et al.
(författare)
-
Arsenic in soil and groundwater : an overview
- 2007. - 9
-
Ingår i: Arsenic in Soil and Groundwater Environment. - Amsterdam, The Netherlands : Elsevier. - 9780444518200 ; , s. 3-60
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Contamination of the environment with arsenic (As) from both anthropogenic and natural sources has occurred in many parts of the world and is recognized as a global problem. Principal anthropogenic sources of As include base metal smelters, gold mines, power plants that burn As-rich coals or treated lumber, disposal sites for wastes from As-processing plants, as well as industrial and municipal dump sites. In many areas, the levels of As in the environment have become one of concern and epidemiological studies have documented various adverse health effects on local populations. Arsenic poisoning episodes from exposure to industrial sources have been reported all over the world; for instance, in Japan, where cases have been associated with pollution around As mines and pollution of groundwater around As-using industries and industrial waste burial sites. Other examples of contaminated environments with increased risk for As poisoning include agricultural lands treated with arsenical pesticides, urban areas, war zones defoliated or sprayed with As compounds, and the superfund sites in the United States and other countries. Although a lot of people get exposed, most often, however, it is not possible to associate the exposure to elevated As levels with adverse human health effects. Nevertheless, long-term cumulative exposure to As in these contaminated environments should be a matter of public health concern and scientific interest.
|
|
| 5. |
|
|
| 6. |
- Valiente-Dobon, JJ, et al.
(författare)
-
Evidence for nontermination of rotational bands in Kr-74
- 2005
-
Ingår i: Physical Review Letters. - 1079-7114. ; 95:23
-
Tidskriftsartikel (refereegranskat)abstract
- Three rotational bands in Kr-74 were studied up to (in one case one transition short of) the maximum spin I-max of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I-max. This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I=I-max.
|
|
| 7. |
- Ghosh, A. K., et al.
(författare)
-
Sender side intelligence for TCP throughput enhancement in wired-cum-wireless network
- 2007
-
Ingår i: 2007 IEEE 18th International Symposium on Personal, Indoor and Mobile Radio Communications. - 1424411440 - 9781424411443 ; , s. 4394381-
-
Konferensbidrag (refereegranskat)abstract
- Performance of the TCP Congestion Control Algorithm has been the focus of research over the last decade. In this paper we propose modifications to TCP Congestion Control to improve its performance in wired-cum-wireless networks The key idea to determine the Optimal Congestion Window for a TCP Sender, in a particular network scenario (that corresponds to the fair share of that connection) and keep this congestion window a constant to a point where the fair share in the network has changed considerably from the instance of the calculation of the size of the last window. At this point, the TCP Congestion Window is recalculated according to the nature of new scenario. The proposed mechanism is particularly effective over wireless links, which have an inherently loss-prone nature, as Modified TCP's congestion window being independent of packet losses (be it corruption losses or it congestion losses), keeps transmitting at the same rate at before.
|
|
| 8. |
- Hao, Limin, et al.
(författare)
-
The hedgehog-related gene qua-1 is required for molting in Caenorhabditis elegans
- 2006
-
Ingår i: Developmental Dynamics. - : Wiley. - 1058-8388 .- 1097-0177. ; 235:6, s. 1469-1481
-
Tidskriftsartikel (refereegranskat)abstract
- The Caenorhabditis elegans genome encodes ten proteins that share similarity with Hedgehog through the C-terminal Hint/Hog domain. While most genes are members of larger gene families, qua-1 is a single copy gene. Here we show that orthologs of qua-1 exist in many nematodes, including Brugia malayi, which shared a common ancestor with C. elegans about 300 million years ago. The QUA-1 proteins contain an N-terminal domain, the Qua domain, that is highly conserved, but whose molecular function is not known. We have studied the expression pattern of qua-1 in C. elegans using a qua-1::GFP transcriptional fusion. qua-1 is mainly expressed in hyp1 to hyp11 hypodermal cells, but not in seam cells. It is also expressed in intestinal and rectal cells, sensilla support cells, and the P cell lineage in L1. The expression of qua-1::GFP undergoes cyclical changes during development in phase with the molting cycle. It accumulates prior to molting and disappears between molts. Disruption of the qua-1 gene function through an internal deletion that causes a frame shift with premature stop in the middle of the gene results in strong lethality. The animals arrest in the early larval stages due to defects in molting. Electron microscopy reveals double cuticles due to defective ecdysis, but no obvious defects are seen in the hypodermis. Qua domain-only::GFP and full-length QUA-1::GFP fusion constructs are secreted and associated with the overlying cuticle, but only QUA-1::GFP rescues the mutant phenotype. Our results suggest that both the Hint/Hog domain and Qua domain are critically required for the function of QUA-1.
|
|
| 9. |
|
|
| 10. |
- Mukherjee, A. B., et al.
(författare)
-
Mercury emissions from industrial sources in India and its effects in the environment
- 2009
-
Ingår i: Mercury Fate and Transport in the Global Atmosphere. - Boston, MA : Springer-Verlag New York. - 9780387939575 - 9780387939582 ; , s. 81-112
-
Bokkapitel (refereegranskat)abstract
- This study describes the atmospheric mercury (Hg) emissions from industrial sources in India for the years 2000 to 2004. In India emission inventories of Hg and other trace elements from anthropogenic sources have been largely neglected, although the GDP (Gross Domestic Products growth) has touched 9.6% at the beginning of the 21st century. In coal production India is the third largest in the world, whereas Indian cement and brick production have reached second place in the world. With increased industrial development, acute pollution problems have been identified in the subcontinent. There is no consistent earlier information for Hg emissions to the environment for any sectors of industry. This paper may be the first road map in which we have tried to find out the total emission of Hg from a wide range of sources, e.g. from coal combustion to clinical thermometers broken during production or packing. There is a lack of basic data and in an attempt to correct this, emission factors suitable for Asian countries have been selected to complete this study. Before this document, there were some efforts in Europe to develop emission inventories for Hg from coal combustion or chlor-alkali plants for India. In this study it was found that total atmospheric emission from industrial sources has decreased from 321 Mg in 2000 to 253 Mg in 2004 due to a switch for the membrane cell process in the chlor-alkali industry. In 2004 the largest part of the Hg emissions stemmed from coal combustion in thermal power plants. Hg-cell technology had been used earlier in chlorine and sodium hydroxide production, as a result of which Hg concentration in terrestrial and aquatic species are nowadays quite high in coastal areas. India can thus be referred to as a mercury hot spot. We have received limited information on emissions of Hg from industrial sources in India. Estimates are based on emission factors and the values taken from the literature. Against a background of limited data and information, this paper gives an overview of Hg emissions in India and of the recent steps undertaken by authorities to curb the emissions of Hg and its subsequent trans-boundary movement in the global environment.
|
|
