ALBERT

Description: The variable connectivity index, introduced by the chemist Milan Randić in the first quarter of 1990s, for a graph G is defined as ∑vw∈EGdv+γdw+γ−1/2, where γ is a non-negative real number and dw is the degree of a vertex w in G. We call this index as the variable Randić index and denote it by Rvγ. In this paper, we show that the graph created from the star graph of order n by adding an edge has the minimum Rvγ value among all unicyclic graphs of a fixed order n, for every n≥4 and γ≥0.

Description: There are two known mRNA degradation pathways, 3' to 5' and 5' to 3'. We identified likely pathogenic variants in two genes involved in these two pathways in individuals with intellectual disability. In a large family with multiple branches, we identified biallelic variants in DCPS in three affected individuals; a splice site variant (c.636+1G〉A) that results in an in-frame insertion of 45 nucleotides and a missense variant (c.947C〉T; p.Thr316Met). DCPS decaps the cap structure generated by 3' to 5' exonucleolytic degradation of mRNA. In vitro decapping assays showed an ablation of decapping function for both variants in DCPS. In another family, we identified a homozygous mutation (c.161T〉C; p.Phe54Ser) in EDC3 in two affected children. EDC3 stimulates DCP2, which decaps mRNAs at the beginning of the 5' to 3' degradation pathway. In vitro decapping assays showed that altered EDC3 is unable to enhance DCP2 decapping at low concentrations and even inhibits DCP2 decapping at high concentration. We show that individuals with biallelic mutations in these genes of seemingly central functions are viable and that these possibly lead to impairment of neurological functions linking mRNA decapping to normal cognition. Our results further affirm an emerging theme linking aberrant mRNA metabolism to neurological defects.

Description: We report the discovery and characterization of a new M-dwarf binary, with component masses and radii of $M_1 = 0.244_{-0.003}^{+0.003} \, \mathrm{M}_{\odot }$ , $R_1 = 0.261_{-0.009}^{+0.006} \, \mathrm{R}_{\odot }$ , $M_2 = 0.179_{-0.001}^{+0.002} \, \mathrm{M}_{\odot }$ , $R_2 = 0.218 _{-0.011}^{+0.007} \, \mathrm{R}_{\odot }$ , and orbital period of ~4.1 d. The M-dwarf binary HATS551–027 (LP 837–20) was identified as an eclipsing binary by the HATSouth survey, and characterized by a series of high-precision photometric observations of the eclipse events, and spectroscopic determinations of the atmospheric parameters and radial velocity orbits. HATS551–027 is one of few systems with both stellar components lying in the fully convective regime of very low mass stars, and can serve as a test for stellar interior models. The radius of HATS551–027A is consistent with models to 1, whilst HATS551–027B is inflated by 9 per cent at 2 significance. We measure the effective temperatures for the two stellar components to be T eff, 1  = 3190 ± 100 K and T eff, 2  = 2990 ± 110 K; both are slightly cooler than theoretical models predict, but consistent with other M-dwarfs of similar masses that have previously been studied. We also measure significant H α emission from both components of the binary system, and discuss this in the context of the correlation between stellar activity and the discrepancies between the observed and model temperatures.

Description: We propose decoupling energy and sensing planes in WSN. This decoupling represents a paradigm shift as it can alleviate the fundamental problem of energy depletion in WSN and can (in theory) offer a sensor network with infinite lifetime. We present energy transference as the mode of decoupling energy by allowing energy to move between energy-rich and energy-poor nodes. We present a first practical energy distribution architecture that allows us to decouple energy supply from sensing activities. Such a separation of responsibilities enables us to utilize abundant energy sources distant from the sensing location, allowing unrestricted lifetime and resolving unequal energy consumption in WSN. We demonstrate energy transfer for practical decoupling using low-cost and low-footprint, laser μ-power beaming that powers current WSN platforms at 100 m of range. We design and implement LAMP, a tiered architecture to manage energy supply to both mesh and clustered WSN deployments using an energy distribution protocol. We evaluate our system to show that, for an additional cost of $29 per mote, LAMP can support perpetual mesh functionality for up to 40 sensors or 120 nodes in clustered operation.

Description: International Journal of Distributed Sensor Networks, Volume 15, Issue 6, June 2019. 〈br/〉In underwater wireless sensor networks, stability and reliability of the network are of paramount importance. Stability of the network ensures persistent operation of the network that, in consequence, avoids data loss when nodes consume all the battery power and subject to death. Particularly, nodes bearing a low pressure of water die early in the usual routing approach due to being preferred choices for data routing. Reliability ensures minimization of the adverse channel effects on data packets so that the desired information is easily extracted from these packets. This article proposes two routing protocols for underwater wireless sensor networks: reliable and stability-aware routing and cooperative reliable and stability-aware routing. In reliable and stability-aware routing, energy assignment to a node is made on the basis of its depth. Sensor nodes having the lowest depth are assigned the highest amount of energy. This energy assignment is called the energy grade of a node and five energy grades are formed in the proposed network from top to bottom. The energy grade along with energy residing in a node battery and its depth decide its selection as a forwarder node. The reliable and stability-aware routing uses only a single link to forward packets. Such a link may not be reliable always. To overcome this issue, the cooperative reliable and stability-aware routing is proposed which introduces cooperative routing to reliable and stability-aware routing. Cooperative routing involves the reception of multiple copies of data symbols by destination. This minimizes the adverse channel effects on data packets and makes the information extraction convenient and less cumbersome at the final destination. Unlike the conventional approach, the proposed schemes do not take into account the coordinates of nodes for defining the routing trajectories, which is challenging in underwater medium. Simulation results reveal a better behavior of the proposed protocols than some competitive schemes in terms of providing stability to the network, packet transfer to the ultimate destination, and latency.

Description: We present a control strategy for nonlinear nontriangular uncertain systems. The proposed control method is a synergy between the dynamic adaptive backstepping (DAB) and integral sliding mode (ISM) and is referred to as DAB-ISMC. Our main objective is to find a recursive procedure to transform a nontriangular system into an implementable form that enables designing a control law which almost eliminates the reaching-phase. The proposed method further facilitates minimization of chattering which is believed to be a shortcoming of the sliding mode control. In this methodology, the ISM, as an integrated subsystem of DAB, is introduced at the final stage of backstepping. This strategy works very well to obtain a system that is robust against model imperfections, matching and unmatching uncertainties. The DAB-ISMC method is applied on a continuous stirred tank reactor (CSTR) and simulation results obtained on Matlab are found to be very promising.

Description: By using the dense coverage of the extrasolar planet survey project HATNet (Hungarian-made Automated Telescope Network), we Fourier analyse 381 high-probability members of the nearby open cluster Praesepe (Beehive/M44/NGC 2632). In addition to the detection of 10 variables (of Scuti and other types), we identify 180 rotational variables (including the two known planet hosts). This sample increases the number of known rotational variables in this cluster for spectral classes earlier than M by more than a factor of 3. These stars closely follow a colour/magnitude–period relation from early F to late K stars. We approximate this relation by polynomials for an easier reference to the rotational characteristics in different colours. The total (peak-to-peak) amplitudes of the large majority (94 per cent) of these variables span the range of 0.005–0.04 mag. The periods cover a range from 2.5 to 15 d. These data strongly confirm that Praesepe and the Hyades have the same gyrochronological ages. Regarding the two planet hosts, Pr0211 (the one with the shorter orbital period) has a rotational period that is ~2 d shorter than the one expected from the main rotational pattern in this cluster. This, together with other examples discussed in the paper, may hint that star–planet interaction via tidal dissipation can be significant in some cases in the rotational evolution of stars hosting hot Jupiters.

Description: In this paper, we have investigated the role of different fluid parameters particularly electromagnetic field and f ( R ) corrections on the evolution of cylindrical compact object. We have explored the modified field equations, kinematical quantities and dynamical equations. An expression for the mass function has been found in comparison with the Misner–Sharp formalism in modified gravity, after which different mass–radius diagrams are drawn. The coupled dynamical transport equation have been formulated to discuss the role of thermoinertial effects on the inertial mass density of the cylindrical relativistic interior. Finally, we have presented a framework, according to which all possible solutions of the metric f ( R )-Maxwell field equations coupled with static fluid can be written through set of scalar functions. It is found that modified gravity induced by Lagrangians f ( R ) = α R 2 , f ( R ) = α R 2 – β R and $f(R)=\frac{\alpha R^2-\beta R}{1+\gamma R}$ are likely to host more massive cylindrical compact objects with smaller radii as compared to general relativity.

Description: Different concentrations of Mg-doped ZnO nanoparticles (NPs) were synthesized by coprecipitation technique at 60°C. XRD data are used to study phase purity and crystal structure in different doping concentrations. The results indicated that increasing the doping from 0~7.5 wt.% caused a subsequent increase in FWHM in XRD and an associated systematic shift towards higher wavelength in the optical properties. Finally, the sensing of UV light is tested by observing the response of nanoparticles by exposing them to UV light and measuring the resistance in presence and absence of UV light.

Description: The authors propose a new tracking control design strategy for uncertain non-linear systems which are convertible to Semi-Strict Feedback Form (SSFF). The system in SSFF is first converted into new variables via existing adaptive backstepping control techniques. The control law is obtained by combining adaptive backstepping procedure and higher order integral sliding mode. The component of control law designed via backstepping is continuous which shows robustness against parametric uncertainties where as the discontinuous control component provides robustness against unmodeled dynamics and external disturbances. Since, this strategy relies on an integral manifold of the adaptively developed variables, therefore, the reaching phase is eliminated in this approach, which is an advantage in term of robustness. Furthermore, the parameters update law correctly provides the estimation of parameters which is again results in enhanced robustness of the strategy. The stability of proposed method is analysed theoretically and validated through a numerical example.