Model systems for aging research: syncretic concepts and diversity of mechanisms

Genome ◽  
1989 ◽  
Vol 31 (1) ◽  
pp. 406-412 ◽  
Author(s):  
Robert J. Shmookler Reis

A variety of very different phenomena have been subsumed under the heading of "aging" research. A review of recent experimental data, in several of the best-studied model systems for the investigation of aging, indicates that molecular changes which are putative or demonstrated proximal causes of senescent deterioration are generally not shared by other systems examined. It is thus argued that different aberrant biochemical processes have evolved as the "weakest link" limiting longevity or intermeiotic interval in different systems, although in each case the germ line must be exempted.Key words: aging, senescence, meiosis, DNA, RNA.

2015 ◽  
Vol 11 (2) ◽  
pp. 2972-2978
Author(s):  
Fouad A. Majeed ◽  
Yousif A. Abdul-Hussien

In this study the calculations of the total fusion reaction cross section have been performed for fusion reaction systems 17F + 208Pb and 15C + 232Th which involving halo nuclei by using a semiclassical approach.The semiclassical treatment is comprising the WKB approximation to describe the relative motion between target and projectile nuclei, and Continuum Discretized Coupled Channel (CDCC) method to describe the intrinsic motion for both target and projectile nuclei. For the same of comparsion a full quantum mechanical clacualtions have been preforemd using the (CCFULL) code. Our theorticalrestuls are compared with the full quantum mechaincialcalcuations and with the recent experimental data for the total fusion reaction  checking the stability of the distancesThe coupled channel calculations of the total fusion cross section σfus, and the fusion barrier distribution Dfus. The comparsion with experiment proves that the semiclassiacl approach adopted in the present work reproduce the experimental data better that the full quantal mechanical calcautions. 


2010 ◽  
Vol 20 (3) ◽  
pp. 193
Author(s):  
Doan Nhat Quang ◽  
Nguyen Huyen Tung ◽  
Nguyen Trung Hong ◽  
Tran Thi Hai

We present a theoretical study of the effects from symmetric modulation of the envelop wave function on quantum transport in square quantum wells (QWs). Within the variational approach we obtain analytic expressions for the carrier distribution and their scattering in symmetric two-side doped square QWs. Roughness-induced scattering are found significantly weaker than those in the asymmetric one-side doped counterpart. Thus, we propose symmetric modulation of the wave function as an efficient method for enhancement of the roughness-limited QW mobility. Our theory is able to well reproduce the recent experimental data about low-temperature transport of electrons and holes in two-side doped square QWs, e.g., the mobility dependence on the channel width, which have not been explained so far.


1978 ◽  
Vol 31 (5) ◽  
pp. 451 ◽  
Author(s):  
DP Bhattacharyya

A study is made of the influence of long-term solar modulation on the low energy sea level muon spectrum near the geomagnetic equator. Recent experimental data are compared with theoretical results calculated from the phenomenological model of Allkofer and Dau. It is suggested that the observed enhancement in the muon intensity is mainly due to a shift in the solar potential.


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