On the Expressivity of Multidimensional Markov Reward

We consider the expressivity of Markov rewards in sequential decision making under uncertainty. We view reward functions in Markov Decision Processes (MDPs) as a means to characterize desired behaviors of agents. Assuming desired behaviors are specified as a set of acceptable policies, we investigate if there exists a scalar or multidimensional Markov reward function that makes the policies in the set more desirable than the other policies. Our main result states both necessary and sufficient conditions for the existence of such reward functions. We also show that for every non-degenerate set of deterministic policies, there exists a multidimensional Markov reward function that characterizes itComment: Presented at RLDM Workshop on Reinforcement Learning as a Model of Agenc

Cyclic phosphatidic acid influences the expression and regulation of cyclic nucleotide phosphodiesterase 3B and lipolysis in 3T3-L1 cells

Cyclic phosphatidic acid (CPA) is found in cells from slime mold to humans and has a largely unknown function. We previously reported that cPA significantly inhibited the lipid accumulation in 3T3-L1 adipocytes through inhibition of PPAR gamma activation. We find here that CPA reduced intracellular triglyceride levels and inhibited the phosphodiesterase 3B (PDE3B) expression in 3T3-L1 adipocytes. PPAR gamma activation in adipogenesis that can be blocked by treatment with cPA then participates in adipocyte function through inhibition of PDE3B expression. We also found the intracellular cAMP levels in 3T3-L1 adipocytes increased after exposure to cPA. These findings contribute to the participation of cPA on the lipolytic activity in 3T3-L1 adipocytes. Our studies imply that CPA might be a therapeutic compound in the treatment of obesity and obesity-related diseases.ArticleBIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. 404(1):109-114 (2011)journal articl

Hydrogenation of toluene on Ni-Co-Mo supported zeolite catalysts

Mixed oxides of Ni, Co and Mo supported on five zeolites -ZSM-5-a, ZSM-5-b, HY-a, HY-b and Mordenite were prepared and characterized using many techniques for use as hydrotreating catalysts. In a preliminary investigation, toluene was employed as model compound to test the catalysts in hydrogenation, as a major upgrading reaction. TGA/DSC analysis showed that the impregnation of the metals slightly affected the thermal stability of the zeolites with all catalytic samples displaying good stability up to 730oC.The XRD patterns for all the catalytic samples showed that the framework of the zeolites were retained after impregnation. XRD and TPR results confirmed the presence of molybdenum trioxide on the zeolites with NiCoMo/HY-b displaying high metal-support interaction due to low reduction temperatures. The activity results showed that toluene conversion of almost 100% and selectivity to mainly methyl-cyclohexane was achieved. The catalysts activity test showed that the zeolite support textural properties particularly surface area, pore volume and pore diameter affect the performance of the catalysts. NiCoMo/HY-b displayed the best performance after the few minutes of the reaction due to its high surface area, pore volume and average pore diameter.Keywords: Hydro treating catalysts; Hydrogenation; Toluene conversion; Surface area; Pore diamete

The CPEB Protein Orb2 Has Multiple Functions during Spermatogenesis in Drosophila melanogaster

Cytoplasmic Polyadenylation Element Binding (CPEB) proteins are translational regulators that can either activate or repress translation depending on the target mRNA and the specific biological context. There are two CPEB subfamilies and most animals have one or more genes from each. Drosophila has a single CPEB gene, orb and orb2, from each subfamily. orb expression is only detected at high levels in the germline and has critical functions in oogenesis but not spermatogenesis. By contrast, orb2 is broadly expressed in the soma; and previous studies have revealed important functions in asymmetric cell division, viability, motor function, learning, and memory. Here we show that orb2 is also expressed in the adult male germline and that it has essential functions in programming the progression of spermatogenesis from meiosis through differentiation. Like the translational regulators boule (bol) and off-schedule (ofs), orb2 is required for meiosis and orb2 mutant spermatocytes undergo a prolonged arrest during the meiotic G2-M transition. However, orb2 differs from boule and off-schedule in that this arrest occurs at a later step in meiotic progression after the synthesis of the meiotic regulator twine. orb2 is also required for the orderly differentiation of the spermatids after meiosis is complete. The differentiation defects in orb2 mutants include abnormal elongation of the spermatid flagellar axonemes, a failure in individualization and improper post-meiotic gene expression. Amongst the orb2 differentiation targets are orb and two other mRNAs, which are transcribed post-meiotically and localized to the tip of the flagellar axonemes. Additionally, analysis of a partial loss of function orb2 mutant suggests that the orb2 differentiation phenotypes are independent of the earlier arrest in meiosis

Numerical analysis of a micro horizontal axis wind turbine tower under extreme loads

One of the major challenges in the development of horizontal axis wind turbine is the selection of appropriate and cost effective tower that will elevate the rotor meters above the ground for wind energy harvest. In this work a tubular structural steel material having an external diameter of 0.1 m, internal diameter of 0.092 m and height of 10 m was selected based on cost, mechanical properties and market availability for the tower. Response of this tower material due to simultaneously applied extreme static, dynamic and aerodynamic loading conditions was analyzed in terms of frequency of vibration, deformation and stress using the numerical code COMSOL Multi-physics 5.2. Three dimensional model of the structural steel tower was developed and boundary conditions defined in the numerical code’s model wizard interface. The tower was considered as a cantilever and a static load of 2128.77 N was applied at 10 m height in the plane. Dynamic load of 413.96 N was applied on the tower in the x,y,z planes and an aerodynamic load of 4967.58 N was applied as uniformly distributed loads in the x plane. Extra fine regular quadrilateral mesh was generated for the computation. Frequency response result of the transfer function at 110 GHz excitation shown in terms of electric field norm was uniformly distributed at the outer boundary layer of the tower with a minimum value of 3.7 x 10-79 V/m. The result of the deformation analysis under the predefined extreme loading conditions shows a maximum deflection value of 197 mm at 10 m height and 0 mm at 0 m height of the tower. Additionally, the stress analysis result shows a predicted maximum value 3.28 x 106 N/m2 between 0 m and 1.98 m height of the tower in the wind direction. The deformation was within the elastic limit of the tower material, because the total exerted extreme loads without the self-weight of the tower (2,397.54 N) was less than the determined safe load of the tower (7,107.96 N). The study has established that the selected horizontal axis wind turbine (HAWT) tower material was reliable under the predefined simultaneously applied extreme loads, thus the structural steel tower can function in areas this or similar loading conditions

Performance Analysis of Horizontal Axis Wind Turbine using Variable Blade Pitch Control Mechanism

This work investigates the performance of a horizontal axis wind turbine (HAWT) with variable blade pitch control mechanism. The control mechanism is a simple mechanical Watt governor design, which was developed to regulate the blade pitch angle of the HAWT depending on wind speed magnitude. The HAWT model with the control mechanism was tested for performance in a wind tunnel. Response of the control mechanism in terms of blade pitch angle, rotor speed and generator power output were analyzed based on regulated predetermined wind speeds. The result shows a gradual increase in rotor speed and a proportional increase in generator power output between cut-in wind speed of 2.5m/s and rated wind speed of 6 m/s. These parameters were kept constant at 100 RPM and 50 Watts as observed due to the steady response of the control mechanism. The steadiness lasted up to a cut-out wind speed of 9 m/s. The control mechanism subsequently shutdown the turbine at the cut-out wind speed to protect the turbine against wind speeds higher than 9 m/s. The performance test predicts that the variable blade pitch control mechanism was able to regulate and bring about the require control of HAWT model. The mechanism allows the turbine to only operate between 2.5 and 9 m/s at blade pitch angle between 82 and 90 degrees from the axis of wind flow and change in governor height between 0 to 8 mm

Cyclic phosphatidic acid decreases proliferation and survival of colon cancer cells by inhibiting peroxisome proliferator-activated receptor gamma

Cyclic phosphatidic acid (CPA) a structural analog of lysophosphatidic acid (LPA) is one of the simplest phospholipids found in every cell type cPA is a specific high-affinity antagonist of peroxisome proliferator-activated receptor gamma (PPAR gamma) however the molecular mechanism by which cPA inhibits cellular proliferation remains to be clarified In this study we found that inhibition of PPAR gamma prevents proliferation of human colon cancer HT-29 cells CPA suppressed cell growth and this effect was reversed by the addition of a PPAR gamma agonist These results indicate that the physiological effects of cPA are partly due to PPAR gamma inhibition Our results identify PPAR gamma as a molecular mediator of CPA activity in HT-29 cells and suggest that cPA and the PPAR gamma pathway might be therapeutic targets in the treatment of colon cancerArticlePROSTAGLANDINS & OTHER LIPID MEDIATORS. 93(3-4):126-133 (2010)journal articl

Usable Privacy Mechanisms in Home Security Camera Systems

IoT is the interconnection of People and things. When our home is connected to IoT devices it is referred to as smart home. The idea behind smart home is to make life easier such that there is little human intervention. The IoT devices in our smart home exchange data for storage and processing. This exchange of data leads to users concerns on data security and privacy. In this work, we implemented home security camera systems in such a way that the data is encrypted first before being sent to the cloud in a very simplified and almost automatic encryption process. This implementation was done putting in mind usability. A questionnaire was used to gather results on users’ perception about the system. The user study conducted yielded positive result