Unconventional Charge Density Wave Arising from Electron–Phonon Interaction

We report of a theoretical study on quasi-one dimensional unconventional charge density wave (UCDW) driven by electron–phonon interaction. Within mean field theory, we find that the wavevector dependence of the coupling leads to a momentum dependent single particle gap on the Fermi surface. The presence of small energy single particle excitations around the gap nodes significantly changes the optical conductivity compared to the conventional CDW result. In addition to that, the collective phase excitation arising from fluctuation of the order parameter leads to further qualitative changes of the conductivity and results in an effective mass that is nonmonotonic in temperature.      

Differential Subcellular Distribution of Cytokinins: How Does Membrane Transport Fit into the Big Picture?

Cytokinins are a class of phytohormones, signalling molecules specific to plants. They act as regulators of diverse physiological processes in complex signalling pathways. It is necessary for plants to continuously regulate cytokinin distribution among different organs, tissues, cells, and compartments. Such regulatory mechanisms include cytokinin biosynthesis, metabolic conversions and degradation, as well as cytokinin membrane transport. In our review, we aim to provide a thorough picture of the latter. We begin by summarizing cytokinin structures and physicochemical properties. Then, we revise the elementary thermodynamic and kinetic aspects of cytokinin membrane transport. Next, we review which membrane-bound carrier proteins and protein families recognize cytokinins as their substrates. Namely, we discuss the families of “equilibrative nucleoside transporters” and “purine permeases”, which translocate diverse purine-related compounds, and proteins AtPUP14, AtABCG14, AtAZG1, and AtAZG2, which are specific to cytokinins. We also address long-distance cytokinin transport. Putting all these pieces together, we finally discuss cytokinin distribution as a net result of these processes, diverse in their physicochemical nature but acting together to promote plant fitness.     

Comments on “Necessary and sufficient stability condition of fractional-order interval linear systems” [Automatica 44 (2008), 2985–2988]

This paper shows that the main thesis of the article “Necessary and sufficient stability condition of fractional-order interval linear systems” by Ahn and Chen (Automatica, vol. 44, pp. 2985–2988) is only a sufficient (and not a necessary) condition for the robust stability of fractional-order linear systems.     

Changes in the size and docosahexaenoic acid content of adipocytes during chick embryo development

The development of adipose tissue in the chick embryo was investigated using two groups of fertile eggs which differed by 1.7-fold in their initial yolk lipid levels. The triacylglycerol content of the subcutaneous adipose depot in both groups increased dramatically from day 12 of the 21-day embryonic period, attaining a maximal value just prior to hatching. During this period, the amount of triacylglycerol deposited in the adipose tissue was very highly correlated with the amount of lipid transferred from the yolk. The triacylglycerol content of the depot was also dependent on the initial yolk lipid content. During the hatching period, the amount of adipose triacylglycerol remained approximately constant in the group with the higher initial yolk lipid content but, in the case of the group with the lower initial yolk lipid levels, decreased by approximately 25%. The size distribution of adipocytes isolated from the tissue was determined by computerized image analysis microscopy. The mean adipocyte diameter increased from approximately 6 to 35 μm between days 12 and 19, irrespective of the initial yolk content, although development within the eggs with the lower initial yolk content resulted in a decrease in cell size over the hatching period. Both the triacylglycerol and phospholipid fractions of the isolated adipocytes contained substantial proportions (approximately 6%, w/w) of docosahexaenoic acid (DHA) at days 12 and 14, and lower levels of this fatty acid at the later stages. The amount (mg/depot) of DHA in adipose triacylglycerol decreased dramatically over the hatching period. The amount (mg/brain) of DHA in brain phospholipid increased by more than 5-fold between day 12 of development and hatching. A possible explanation for the data may be that DHA is preferentially mobilized from adipose tissue in order to deliver the fatty acid to the developing neural tissues in a form suitable for uptake.     

An approach to reduce energy consumption and performance losses on heterogeneous servers using power capping

Journal of Scheduling - Rapid growth of demand for remote computational power, along with high energy costs and infrastructure limits, has led to treating power usage as a primary constraint in...     

SONIC: streaming overlapping community detection

A community within a graph can be broadly defined as a set of vertices that exhibit high cohesiveness (relatively high number of edges within the set) and low conductance (relatively low number of edges leaving the set). Community detection is a fundamental graph processing analytic that can be applied to several application domains, including social networks. In this context, communities are often overlapping, as a person can be involved in more than one community (e.g., friends, and family); and evolving, since the structure of the network changes. We address the problem of streaming overlapping community detection, where the goal is to maintain communities in the presence of streaming updates. This way, the communities can be updated more efficiently. To this end, we introduce SONIC—a find-and-merge type of community detection algorithm that can efficiently handle streaming updates. SONIC first detects when graph updates yield significant community changes. Upon the detection, it updates the communities via an incremental merge procedure. The SONIC algorithm incorporates two additional techniques to speed-up the incremental merge; min-hashing and inverted indexes. Results show that SONIC can provide high quality overlapping communities, while handling streaming updates several orders of magnitude faster than the alternatives performing from-scratch computation.     

Modelling and solving grid resource allocation problem with network resources for workflow applications

A problem of allocating resources of a grid to workflow applications is considered. The problem consists, generally, in allocating distributed grid resources to tasks of a workflow in such a way that the resource demands of each task are satisfied. Grid resources are divided into computational resources and network resources. Computational tasks and transmission tasks of a workflow are distinguished. We present a model of the problem, and an algorithm for finding feasible resource allocations. A numerical example is included, showing the importance of the resource allocation phase on a grid. Some conclusions and directions for future research are given.     

Understanding dengue fever dynamics: a study of seasonality in vector-borne disease models

Dengue fever dynamics show seasonality, with the disease transmission being higher during the warmer seasons. In this paper, we analyse seasonally forced epidemic models with and without vector dynamics. We assume small seasonal effects and obtain approximations for the real response of each state variable and also for the corresponding amplitude and phase via decomposition of the sinusoidal forcing into imaginary exponential functions. The analysis begins with the simplest susceptible-infected-susceptible (SIS) model, followed by the simplest model with vector dynamics, susceptible-infected-susceptible for hosts and uninfected-vector (SISUV). Finally, we compare the more complex susceptible-infected-recovered (SIR) and susceptible-infected-recovered for hosts and uninfected-vector (SIRUV) models and conclude that the models give basically the same information when we replace, in the SIR model, the human infectivity by a function of both human and mosquito infectivities.