| 1. |
- Abazov, V. M., et al.
(författare)
-
The upgraded DO detector
- 2006
-
Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
-
Tidskriftsartikel (refereegranskat)abstract
- The DO experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid -argon calorimeters and central muon detector, remaining from Run 1, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DO.
|
|
| 2. |
- Chen, Li-Jen, et al.
(författare)
-
Observation of energetic electrons within magnetic islands
- 2008
-
Ingår i: Nature Physics. - : Nature Publishing Group. - 1745-2473 .- 1745-2481. ; 4:1, s. 19-23
-
Tidskriftsartikel (refereegranskat)abstract
- Magnetic reconnection is the underlying process that releases impulsively an enormous amount of magnetic energy(1) in solar flares(2,3), flares on strongly magnetized neutron stars(4) and substorms in the Earth's magnetosphere(5). Studies of energy release during solar flares, in particular, indicate that up to 50% of the released energy is carried by accelerated 20-100 keV suprathermal electrons(6-8). How so many electrons can gain so much energy during reconnection has been a long-standing question. A recent theoretical study suggests that volume-filling contracting magnetic islands formed during reconnection can produce a large number of energetic electrons(9). Here we report the first evidence of the link between energetic electrons and magnetic islands during reconnection in the Earth's magnetosphere. The results indicate that energetic electron fluxes peak at sites of compressed density within islands, which imposes a new constraint on theories of electron acceleration.
|
|
| 3. |
|
|
| 4. |
- 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.
|
|
| 5. |
- Chen, Li-Jen, et al.
(författare)
-
Evidence of an extended electron current sheet and its neighboring magnetic island during magnetotail reconnection
- 2008
-
Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 113:A12, s. A12213-
-
Tidskriftsartikel (refereegranskat)abstract
- We have identified a spatially extended electron current sheet (ECS) and its adjacent magnetic island during a magnetotail reconnection event with no appreciable guide field. This finding is based on data from the four Cluster spacecraft and is enabled by detailed maps of electron distribution functions and DC electric fields within the diffusion region. The maps are developed using two-dimensional particle-in-cell simulations with a mass ratio m(i)/m(e) = 800. One spacecraft crossed the ECS earthward of the reconnection null and, together with the other three spacecraft, registered the following properties: (1) The ECS is colocated with a layer of bipolar electric fields normal to the ECS, pointing toward the ECS, and with a half width less than 8 electron skin depths. (2) In the inflow region up to the ECS and separatrices, electrons have a temperature anisotropy (Te-parallel to/Te-perpendicular to > 1), and the anisotropy increases toward the ECS. (3) Within about 1 ion skin depth (d(i)) above and below the ECS, the electron density decreases toward the ECS by a factor of 3-4, reaching a minimum at edges of the ECS, and has a local distinct maximum at the ECS center. (4) A di-scale magnetic island is attached to the ECS, separating it from another reconnection layer. Our simulations established that the electric field normal to the ECS is due to charge imbalance and is of the ECS scale, and ions exhibit electron-scale structures in response to this electric field.
|
|
| 6. |
- El-Sheikh, A, et al.
(författare)
-
A selective tumor microvasculature thrombogen that targets a novel receptor complex in the tumor angiogenic microenvironment
- 2005
-
Ingår i: Cancer Research. - 1538-7445. ; 65:23, s. 11109-11117
-
Tidskriftsartikel (refereegranskat)abstract
- We have previously shown that part of the heparin-binding domain of the vascular endothelial growth factor (VEGF), designated HBDt, localizes very selectively to surfaces of the endothelial cells of U blood vessels. Here, we have coupled the HBDt to the extracellular domain of tissue factor (TFt), to locally initiate the thrombogenic cascade. In tumor-bearing mice, infusion of this HBDt.TFt results in rapid occlusive thrombosis selective only for tumor microvasculature with resultant infarctive destruction of tumors. We now show that infusion of an optimal combination of this HBDt.TFt and its requisite cofactor (factor VIIa) in tumor models results in significant tumor eradication. Binding studies and confocal microscopy indicate that the target for the HBDt.TFt seems to be a trimolecular complex of chondroitin C sulfate proteoglycan, neuropilin-1, and VEGF receptor-2, overexpressed together only in highly angiogenic sites of the tumor microenvironment. The HBDt.TFt was also colocalized with the trimolecular receptor complex in endothelial sprouts from tumor tissues, and its binding inhibited the growth of such sprouts. In vitro, we show that the HBDt structure has its highest affinity for chondroitin 6 sulfate. We show the potential of this HBDt.TFt as a candidate therapeutic and elucidate its target in vivo.
|
|
| 7. |
- Maitra, M., et al.
(författare)
-
An intelligent location management strategy for next generation wireless networks : A rule base approach
- 2005
-
Ingår i: 2005 IEEE Wireless Communications and Networking Conference. - : IEEE Communications Society. - 0780389662 ; , s. 1365-1370
-
Konferensbidrag (refereegranskat)abstract
- This work proposes an integrated location management scheme, which essentially rests on our previous work in which we proposed a novel Rule-Based Paging Scheme (RBPS) for reducing the cost for terminal paging in a cellular wireless environment The present work is an enhancement, where we extend our previous work to propose a complete location management scheme. This requires application of RBPS together with a judicious movement based location update (LU) scheme. Numerical results show that proposed integrated location management scheme, which we call, RBPS*, not only attempts to resolve the issue of inherent tradeoff between the cost components, comprising of paging and LU cost, it does reduce the total cost for location management compared to the other schemes referred in this work. RBPS* significantly outperforms RBPS and GSM-adopted blanket paging scheme along with movement based LU. When compared with the popular Shortest Distance First (SDF) scheme, results are again encouraging. The proposed scheme, RBPS*, is a generic one and can be deployed on-line. It has the potential for use in next generation wireless networks, irrespective of any standards.
|
|
| 8. |
- Maitra, M., et al.
(författare)
-
Real time implementations aspects of an intelligent rule based paging scheme
- 2005
-
Ingår i: 2005 IEEE International Conference on Personal Wireless Communications. - : IEEE. - 0780389646 ; , s. 379-383
-
Konferensbidrag (refereegranskat)abstract
- In our earlier work we proposed a novel rule-based approach for locating a mobile terminal (MT) in a mobile cellular wireless networks. The scheme, which we called Rule-Based Paging Scheme (RBPS), significantly outperformed GSM-adopted blanket paging scheme. We have found that when compared with the popular Shortest Distance First (SDF) scheme, results are again encouraging. However, in this work, we have discussed the real time implementation of our proposed scheme and compared performance of the RBPS-adopted blanket paging scheme with GSM-adopted blanket paging scheme, as it is most popularly practiced in real life. The scheme is a generic one and has the potential for use in the next generation wireless networks, irrespective of any standards.
|
|
