663 research outputs found
Edge overload breakdown in evolving networks
We investigate growing networks based on Barabasi and Albert's algorithm for
generating scale-free networks, but with edges sensitive to overload breakdown.
the load is defined through edge betweenness centrality. We focus on the
situation where the average number of connections per vertex is, as the number
of vertices, linearly increasing in time. After an initial stage of growth, the
network undergoes avalanching breakdowns to a fragmented state from which it
never recovers. This breakdown is much less violent if the growth is by random
rather than preferential attachment (as defines the Barabasi and Albert model).
We briefly discuss the case where the average number of connections per vertex
is constant. In this case no breakdown avalanches occur. Implications to the
growth of real-world communication networks are discussed.Comment: To appear in Phys. Rev.
AC-conductance of a quantum wire with electron-electron interaction
The complex ac-response of a quasi-one dimensional electron system in the
one-band approximation with an interaction potential of finite range is
investigated. It is shown that linear response is exact for this model. The
influence of the screening of the electric field is discussed. The complex
absorptive conductance is analyzed in terms of resistive, capacitive and
inductive behaviors.Comment: 13 pages, REVTeX, 7 eps figures, to appear in Phys. Rev.
tumor infiltrating lymphocytes tils as an independent prognostic factor for early her2 breast cancer patients treated with adjuvant chemotherapy and trastuzumab in the randomized shorther trial
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191pd_pr9 weeks versus 1 year adjuvant trastuzumab for her2 early breast cancer subgroup analysis of the shorther trial allows to identify patients for whom a shorter trastuzumab administration may have a favourable risk benefit ratio
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Renormalization approach for quantum-dot structures under strong alternating fields
We develop a renormalization method for calculating the electronic structure
of single and double quantum dots under intense ac fields. The nanostructures
are emulated by lattice models with a clear continuum limit of the
effective-mass and single-particle approximations. The coupling to the ac field
is treated non-perturbatively by means of the Floquet Hamiltonian. The
renormalization approach allows the study of dressed states of the nanoscopic
system with realistic geometries as well arbitrary strong ac fields. We give
examples of a single quantum dot, emphasizing the analysis of the
effective-mass limit for lattice models, and double-dot structures, where we
discuss the limit of the well used two-level approximation.Comment: 6 pages, 7 figure
Pressure Dependence of the Elastic Moduli in Aluminum Rich Al-Li Compounds
I have carried out numerical first principles calculations of the pressure
dependence of the elastic moduli for several ordered structures in the
Aluminum-Lithium system, specifically FCC Al, FCC and BCC Li, L1_2 Al_3Li, and
an ordered FCC Al_7Li supercell. The calculations were performed using the full
potential linear augmented plane wave method (LAPW) to calculate the total
energy as a function of strain, after which the data was fit to a polynomial
function of the strain to determine the modulus. A procedure for estimating the
errors in this process is also given. The predicted equilibrium lattice
parameters are slightly smaller than found experimentally, consistent with
other LDA calculations. The computed elastic moduli are within approximately
10% of the experimentally measured moduli, provided the calculations are
carried out at the experimental lattice constant. The LDA equilibrium shear
modulus C11-C12 increases from 59.3 GPa in Al, to 76.0 GPa in Al_7Li, to 106.2
GPa in Al_3Li. The modulus C_44 increases from 38.4 GPa in Al to 46.1 GPa in
Al_7Li, then falls to 40.7 GPa in Al_3Li. All of the calculated elastic moduli
increase with pressure with the exception of BCC Li, which becomes elastically
unstable at about 2 GPa, where C_11-C_12 vanishes.Comment: 17 pages (REVTEX) + 7 postscript figure
Symptom clusters in newly diagnosed glioma patients:which symptom clusters are independently associated with functioning and global health status?
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Ensuring Quality in AFRINEST and SATT: Clinical Standardization and Monitoring
Background: Three randomized open-label clinical trials [Simplified Antibiotic Therapy Trial (SATT) Bangladesh, SATT Pakistan and African Neonatal Sepsis Trial (AFRINEST)] were developed to test the equivalence of simplified antibiotic regimens compared with the standard regimen of 7 days of parenteral antibiotics. These trials were originally conceived and designed separately; subsequently, significant efforts were made to develop and implement a common protocol and approach. Previous articles in this supplement briefly describe the specific quality control methods used in the individual trials; this article presents additional information about the systematic approaches used to minimize threats to validity and ensure quality across the trials. Methods: A critical component of quality control for AFRINEST and SATT was striving to eliminate variation in clinical assessments and decisions regarding eligibility, enrollment and treatment outcomes. Ensuring appropriate and consistent clinical judgment was accomplished through standardized approaches applied across the trials, including training, assessment of clinical skills and refresher training. Standardized monitoring procedures were also applied across the trials, including routine (day-to-day) internal monitoring of performance and adherence to protocols, systematic external monitoring by funding agencies and external monitoring by experienced, independent trial monitors. A group of independent experts (Technical Steering Committee/Technical Advisory Group) provided regular monitoring and technical oversight for the trials. Conclusions: Harmonization of AFRINEST and SATT have helped to ensure consistency and quality of implementation, both internally and across the trials as a whole, thereby minimizing potential threats to the validity of the trials’ results
Conclusions and recommendations of a who expert consultation meeting on iron supplementation for infants and young children in malaria endemic areas [Conclusions et recommandations à l\u27issue de la consultation de l\u27oms sur la lutte contre la carence martiale chez le nourrisson et le jeune enfant dans les pays d\u27endémie palustre]
This article presents the results of an expert consultation meeting aimed at evaluating the safety and public health implications of administering supplemental iron to infants and young children in malaria-endemic areas. Participants at this meeting that took place in Lyon, France on June 12-14, 2006 reached consensus on several important issues related to iron supplementation for infants and young children in malaria-endemic areas. The conclusions in this report apply specifically to regions where malaria is endemic
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