756 research outputs found
Thermal stability of a special class of black hole solutions in F(R) gravity
In this paper, we work on the topological Lifshitz-like black hole solutions
of a special class of vacuum gravity that are static and spherically
symmetric. We investigate geometric and thermodynamic properties of the
solutions with due respect to the validity of the first law of thermodynamics.
We examine the van der Waals like behavior for asymptotically AdS solutions
with spherical horizon by studying the , and
diagrams and find a consistent result. We also investigate the same behavior
for hyperbolic horizon and interestingly find that the system under study can
experience a phase transition with negative temperature.Comment: 14 pages with 7 captioned figures. Some additional notes are added.
Accepted in EPJ
The effect of salinity on the growth, morphology and physiology of Echium amoenum Fisch. & Mey.
The salinity of water and soil decreases the growth and yield of agricultural products. Salinity affects many physiological and morphological processes of plant by influencing soil solution osmotic potential and ion absorption and accumulation of minerals. To evaluate the effect of salinity on some physiological and morphological characteristics of the medicinal plant of Echium amoenum, an experiment was carried out with completely random design in four replications. In this study, the effect of different levels of salinity, including control (non-saline water), 3, 6, 9 and 12 dS m-1 from natural saline water was examined on root length, leaf area, dry weight of roots and shoots, also on the amount of absorption of salts Na+, K+, Cl-, Ca2+, Mg2+ and the ratio of Na+/K+ and Ca2+/Na+ in root and shoot of plants and proline and total soluble sugars of leaf in the vegetative growth stage in the greenhouses. Results indicated that the application of saline water reduces significantly all morphological traits under study. Also, as the salinity increased, the density of K+, Ca2+ and Mg2+ and the ratio of Na+/K+ and Ca2+/Na+ in root and shoot of E. amoenum declined. In contrast, by increasing salinity, Na+ and Cl- concentration in roots and shoots significantly increased. As the salinity increased, proline concentration and leaf total soluble sugars also increased significantly compared with the control. The results showed that the accumulation of proline and soluble sugars are good indicators of salinity tolerance. Results also suggest that the plant resists against salinity through osmotic adjustment and ion absorption and sharing within its cells. This process is essential for the survival of plants in saline conditions.Key words: Salinity, Echium amoenum, vegetative growth, ion composition, proline, soluble sugars
Evaluation of the antioxidant activity of dried (rehydrate) and fresh sea cucumber, Holothuria parava
Sea cucumber is a valuable resource containing several materials that can be used as natural products and pharmaceutical industries. In this study, proximate composition and the amount of total phenols, flavonoids and antioxidant activity of fresh and rehydrated (after drying) sea cucumber, Holothuria parva, were examined. The samples were collected from Bandar Lengeh in the Persian Gulf during low tide and kept frozen. The samples were freeze-dried and the moisture content was calculated. The protein, lipid, ash and carbohydrate contents were then measured. The amounts of antioxidant activity (DPPH), phenol and flavonoid contents were also measured. All results have possibility (p<0.05). In fresh sample, the moisture, protein, lipid, ash and carbohydrate contents were 81.20, 12.00, 0.34, 5.50 and 0.95%, respectively, while they were 92.50, 3.76, 0.36, 1.00 and 2.07% in rehydrated sample. The antioxidant activity in fresh and rehydrated samples were equal to 0.063 and 0.060 mg vitamin C/g dry sample, respectively. The IC50 in fresh sample was 5.26 while in the rehydrated sample was 4.14. Total phenol content of fresh and rehydrated samples were equal to 0.22 and 0.19 mg gallic acid/g dry sample, repectively. The flavonoid contents in fresh and rehydrated samples were equal to 3.86 and 5.02 mg Quercetin/g dry sample, respectively. The amounts of protein and ash in fresh sample were significantly higher than rehydrated sample with significant difference (p<0.05). Moisture in rehydrated sample was significantly higher than fresh sample with significant difference (p<0.05). There were no significant difference between fresh and rehydrated samples in terms of their phenon and flavonoid contents. The DPPH radical scavenging capacity was significantly higher in the fresh sample compared to the rehydrated sample with significant difference(p<0.05). It can be concluded that this species of fresh sea cucumber has more antioxidant activity than rehydrated (after drying) sea cucumber and more beneficial to be used in pharmaceutical and food industries
Unidirectional Nonlinear PT-symmetric Optical Structures
We show that non-linear optical structures involving a balanced gain-loss
profile, can act as unidirectional optical valves. This is made possible by
exploiting the interplay between the fundamental symmetries of parity (P) and
time (T), with optical nonlinear effects. This novel unidirectional dynamics is
specifically demonstrated for the case of an integrable PT-symmetric nonlinear
system.Comment: 6 pages,5 figure
Risk-Based Capacitor Placement in Distribution Networks
In this paper, the problem of sizing and placement of constant and switching capacitors in electrical distribution systems is modelled considering the load uncertainty. This model is formu- lated as a multicriteria mathematical problem. The risk of voltage violation is calculated, and the stability index is modelled using fuzzy logic and fuzzy equations. The instability risk is introduced as the deviation of our fuzzy-based stability index with respect to the stability margin. The capacitor placement objectives in our paper include: (i) minimizing investment and installation costs as well as loss cost; (ii) reducing the risk of voltage violation; and (iii) reducing the instability risk. The proposed mathematical model is solved using a multi-objective version of a genetic algorithm. The model is implemented on a distribution network, and the results of the experiment are discussed. The impacts of constant and switching capacitors are assessed separately and concurrently. Moreo- ver, the impact of uncertainty on the multi-objectives is determined based on a sensitivity analysis. It is demonstrated that the more the uncertainty is, the higher the system cost, the voltage risk and the instability risk are
EAP-CRA for WiMAX, WLAN and 4G LTE Interoperability
Today we are moving into a âpost-PCâ world! Not many people sit in front of custom built PCs to do their businesses any more. Hand held devices such as iPod Touch, iPhone, Galaxy S3, iPad, Galaxy Tab, Airbook, Notepad etc. are bringing in a new paradigm as to how people use and communicate information. These devices can be thought as a theoretical âblack-boxâ. They are for people who want to use it without wanting to know how they work. Such devices have third generation user interfaces â multi touch, physics and gestures (MPG). They need updates, but the user is not worried of how and where the files are stored. When a new application is installed, the user sees the icon and starts using it. The user is not interested in, what files were installed or where it was installed â there is no file management. The post-PC approach to dealing with software is that itâs discovered on an app store, downloaded with a single touch and deleted with another touch. Updates all come at once from the app store and it all happens behind the scene with minimal user involvement. All this is happening and adopted rapidly because people are able to do a number of things without being restricted to one place. They can download apps, watch movies, listen to news, browse the web etc. while on the move.Griffith Sciences, School of Information and Communication TechnologyFull Tex
Automated Sustainability Compliance Checking Using Process Mining and Formal Logic
Business processes need to have certain constraints such that they can lead
to sustainable outcomes. These constraints can be manifold and their adherence
has to be monitored. In the past compliance checking has been applied in
several business domains without considering certain sustainability aspects,
such as multi-dimensionality and impact level. With my research I want to
contribute to the application of compliance checking techniques for the purpose
of sustainability compliance. In order to achieve this, I want to analyse and
develop data-driven approaches, which allow to automate the task of compliance
checking. The way in which this can be achieved, is be combining methods from
process mining with formal languages that can express sustainability rules in a
machine-readable manner. The main goal is to develop a compliance engine that
can be adapted by ERP systems in order to evaluate sustainability conformance
in business processes
Scattering of a Dirac electron on a mass barrier
The interaction of a wave packet (and in particular the wave front) with a
mass barrier is investigated in one dimension. We discuss the main features of
the wave packet that are inherent to two-dimensional wave packets, such as
compression during reflection, penetration in the case when the energy is lower
than the height of the barrier, waving tails, precursors, and the retardation
of the reflected and penetrated wave packets. These features depend on the
wave-packet envelope function which we demonstrate by considering the case of a
rectangular wave packet with sharp front and trailing edges and a smooth
Gaussian wave packet. The method of Fourier integral for obtaining the
nonstationary solutions is used.Comment: 12 pages, 9 figure
Transmitter and Receiver Architectures for Molecular Communications: A Survey on Physical Design with Modulation, Coding, and Detection Techniques
Inspired by nature, molecular communications (MC), i.e., the use of molecules to encode, transmit, and receive information, stands as the most promising communication paradigm to realize the nanonetworks. Even though there has been extensive theoretical research toward nanoscale MC, there are no examples of implemented nanoscale MC networks. The main reason for this lies in the peculiarities of nanoscale physics, challenges in nanoscale fabrication, and highly stochastic nature of the biochemical domain of envisioned nanonetwork applications. This mandates developing novel device architectures and communication methods compatible with MC constraints. To that end, various transmitter and receiver designs for MC have been proposed in the literature together with numerable modulation, coding, and detection techniques. However, these works fall into domains of a very wide spectrum of disciplines, including, but not limited to, information and communication theory, quantum physics, materials science, nanofabrication, physiology, and synthetic biology. Therefore, we believe it is imperative for the progress of the field that an organized exposition of cumulative knowledge on the subject matter can be compiled. Thus, to fill this gap, in this comprehensive survey, we review the existing literature on transmitter and receiver architectures toward realizing MC among nanomaterial-based nanomachines and/or biological entities and provide a complete overview of modulation, coding, and detection techniques employed for MC. Moreover, we identify the most significant shortcomings and challenges in all these research areas and propose potential solutions to overcome some of them.This work was supported in part by the European Research Council (ERC) Projects MINERVA under Grant ERC-2013-CoG #616922 and MINERGRACE under Grant ERC-2017-PoC #780645
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