A simpler and more efficient algorithm for the next-to-shortest path problem

Given an undirected graph $G=(V,E)$ with positive edge lengths and two vertices $s$ and $t$, the next-to-shortest path problem is to find an $st$-path which length is minimum amongst all $st$-paths strictly longer than the shortest path length. In this paper we show that the problem can be solved in linear time if the distances from $s$ and $t$ to all other vertices are given. Particularly our new algorithm runs in $O(|V|\log |V|+|E|)$ time for general graphs, which improves the previous result of $O(|V|^2)$ time for sparse graphs, and takes only linear time for unweighted graphs, planar graphs, and graphs with positive integer edge lengths.Comment: Partial result appeared in COCOA201

Non-destructive, dynamic detectors for Bose-Einstein condensates

We propose and analyze a series of non-destructive, dynamic detectors for Bose-Einstein condensates based on photo-detectors operating at the shot noise limit. These detectors are compatible with real time feedback to the condensate. The signal to noise ratio of different detection schemes are compared subject to the constraint of minimal heating due to photon absorption and spontaneous emission. This constraint leads to different optimal operating points for interference-based schemes. We find the somewhat counter-intuitive result that without the presence of a cavity, interferometry causes as much destruction as absorption for optically thin clouds. For optically thick clouds, cavity-free interferometry is superior to absorption, but it still cannot be made arbitrarily non-destructive . We propose a cavity-based measurement of atomic density which can in principle be made arbitrarily non-destructive for a given signal to noise ratio

Job Scheduling Using successive Linear Programming Approximations of a Sparse Model

EuroPar 2012In this paper we tackle the well-known problem of scheduling a collection of parallel jobs on a set of processors either in a cluster or in a multiprocessor computer. For the makespan objective, i.e., the completion time of the last job, this problem has been shown to be NP-Hard and several heuristics have already been proposed to minimize the execution time. We introduce a novel approach based on successive linear programming (LP) approximations of a sparse model. The idea is to relax an integer linear program and use lp norm-based operators to force the solver to find almost-integer solutions that can be assimilated to an integer solution. We consider the case where jobs are either rigid or moldable. A rigid parallel job is performed with a predefined number of processors while a moldable job can define the number of processors that it is using just before it starts its execution. We compare the scheduling approach with the classic Largest Task First list based algorithm and we show that our approach provides good results for small instances of the problem. The contributions of this paper are both the integration of mathematical methods in the scheduling world and the design of a promising approach which gives good results for scheduling problems with less than a hundred processors

Magnetic Nanoparticles for Power Absorption: optimizing size, shape and magnetic properties

We present a study on the magnetic properties of naked and silica-coated Fe3O4 nanoparticles with sizes between 5 and 110 nm. Their efficiency as heating agents was assessed through specific power absorption (SPA) measurements as a function of particle size and shape. The results show a strong dependence of the SPA with the particle size, with a maximum around 30 nm, as expected for a Neel relaxation mechanism in single-domain particles. The SiO2 shell thickness was found to play an important role in the SPA mechanism by hindering the heat outflow, thus decreasing the heating efficiency. It is concluded that a compromise between good heating efficiency and surface functionality for biomedical purposes can be attained by making the SiO2 functional coating as thin as possible.Comment: 15 pages, 7 figures, 2 table

Phylogeny and climate explain contrasting hydraulic traits in different life forms of 150 woody Fabaceae species

The contrasting hydraulic traits observed among different plant life forms are shaped by entangled environmental and evolutionary processes. However, we lack understanding of the relative importance of life form, climate and phylogeny in explaining the variance of hydraulic traits. We analysed seven hydraulic traits and eleven climatic variables of 150 Fabaceae species representing three life forms from 62 sites worldwide, using phylogenetic comparative analyses and variance partitioning. The phylogenetic signal found in most traits disappeared after considering life form, indicating that phylogenetic conservatism in traits originated from the divergence among life forms. The trait‐climate relationships were also phylogenetically dependent, implying that trait responses are driven by climate and phylogeny together. Variance partitioning showed that phylogeny and climate explained greater trait variation than life form did. Synthesis. The climate‐driven hydraulic trait responses in Fabaceae still existed with phylogeny being considered, suggesting that this large family may be particularly sensitive to climate change. Our results emphasise the need to include phylogeny in plant hydraulic adaptation studies under future climate change

Theories of Low-Energy Quasi-Particle States in Disordered d-Wave Superconductors

The physics of low-energy quasi-particle excitations in disordered d-wave superconductors is a subject of ongoing intensive research. Over the last decade, a variety of conceptually and methodologically different approaches to the problem have been developed. Unfortunately, many of these theories contradict each other, and the current literature displays a lack of consensus on even the most basic physical observables. Adopting a symmetry-oriented approach, the present paper attempts to identify the origin of the disagreement between various previous approaches, and to develop a coherent theoretical description of the different low-energy regimes realized in weakly disordered d-wave superconductors. We show that, depending on the presence or absence of time-reversal invariance and the microscopic nature of the impurities, the system falls into one of four different symmetry classes. By employing a field-theoretical formalism, we derive effective descriptions of these universal regimes as descendants of a common parent field theory of Wess-Zumino-Novikov-Witten type. As well as describing the properties of each universal regime, we analyse a number of physically relevant crossover scenarios, and discuss reasons for the disagreement between previous results. We also touch upon other aspects of the phenomenology of the d-wave superconductor such as quasi-particle localization properties, the spin quantum Hall effect, and the quasi-particle physics of the disordered vortex lattice.Comment: 42 Pages, 8 postscript figures, published version with updated reference

Synergistic effect of Fe and Ni on carbon aerogel for enhanced oxygen reduction and H₂O₂ activation in electro-Fenton process

A novel cathode, iron-nickel alloy modified carbon aerogel (FeNi-CA), was successfully synthesized and utilized as the cathode in an electro-Fenton process for acetaminophen degradation. The incorporation of Fe and Ni in the carbon matrix resulted in superior electrochemical characteristics and catalytic performance compared to Fe-CA and Ni-CA. The unique microstructure of FeNi-CA, including the presence of alloy nanoparticles, carbon defects, and abundant oxygen functional groups, enhanced 2e⁻ oxygen reduction activity and electrocatalytic performance. This enabled FeNi-CA to exhibit a dual functionality of H₂O₂ electro-generation and in situ activation. FeNi-CA demonstrated good performance over a wide pH range at a low current density of 4.44 mA/cm². Under optimal conditions, 99.9 % of acetaminophen was removed with a reaction rate constant (kobs) of 0.054 min⁻¹ through electro-sorption and oxidation processes. Importantly, a satisfactory degradation effect was achieved in the absence of external aeration. This work provides a potential wastewater treatment solution without the need for external aeration or additional chemical input by simultaneously achieving oxygen evolution reaction at the anode and oxygen reduction reaction at the cathode. Furthermore, FeNi-CA demonstrated good reusability performance with controlled metal leaching after five consecutive runs, suggesting its potential for sustained use in electro-Fenton processes over the long term

Hybrid materials based on polyethylene and MCM-41 microparticles functionalized with silanes: catalytic aspects of in situ polymerization, crystalline features and mechanical properties

New nanocomposites based on polyethylene have been prepared by in situ polymerization of ethylene in presence of mesoporous MCM-41. The polymerization reactions were performed using a zirconocene catalyst either under homogenous conditions or supported onto mesoporous MCM-41 particles, which are synthesized and decorated post-synthesis with two silanes before polymerization in order to promote an enhanced interfacial adhesion. The existence of polyethylene chains able to crystallize within the mesoporous channels in the resulting nanocomposites is figured out from the small endothermic process, located at around 80 C, on heating calorimetric experiments, in addition to the main melting endotherm. These results indicate that polyethylene macrochains can grow up during polymerization either outside or inside the MCM-41 channels, these keeping their regular hexagonal arrangements. Mechanical response is observed to be dependent on the content in mesoporous MCM-41 and on the crystalline features of polyethylene. Accordingly, stiffness increases and deformability decreases in the nanocomposites as much as MCM-41 content is enlarged and polyethylene amount within channels is raised. Ultimate mechanical performance improves with MCM-41 incorporation without varying the final processing temperature

Rapid And Durable Responses With The Syk/Jak Inhibitor Cerdulatinib In A Phase 2 Study In Relapsed/Refractory Follicular Lymphoma—Alone Or In Combination With Rituximab

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149541/1/hon30_2629.pd

Stabilization and pumping of giant vortices in dilute Bose-Einstein condensates

Recently, it was shown that giant vortices with arbitrarily large quantum numbers can possibly be created in dilute Bose-Einstein condensates by cyclically pumping vorticity into the condensate. However, multiply quantized vortices are typically dynamically unstable in harmonically trapped nonrotated condensates, which poses a serious challenge to the vortex pump procedure. In this theoretical study, we investigate how the giant vortices can be stabilized by the application of a Gaussian potential peak along the vortex core. We find that achieving dynamical stability is feasible up to high quantum numbers. To demonstrate the efficiency of the stabilization method, we simulate the adiabatic creation of an unsplit 20-quantum vortex with the vortex pump.Comment: 8 pages, 6 figures; to be published in J. Low Temp. Phys., online publication available at http://dx.doi.org/10.1007/s10909-010-0216-