A Novel Family of Adaptive Filtering Algorithms Based on The Logarithmic Cost

We introduce a novel family of adaptive filtering algorithms based on a relative logarithmic cost. The new family intrinsically combines the higher and lower order measures of the error into a single continuous update based on the error amount. We introduce important members of this family of algorithms such as the least mean logarithmic square (LMLS) and least logarithmic absolute difference (LLAD) algorithms that improve the convergence performance of the conventional algorithms. However, our approach and analysis are generic such that they cover other well-known cost functions as described in the paper. The LMLS algorithm achieves comparable convergence performance with the least mean fourth (LMF) algorithm and extends the stability bound on the step size. The LLAD and least mean square (LMS) algorithms demonstrate similar convergence performance in impulse-free noise environments while the LLAD algorithm is robust against impulsive interferences and outperforms the sign algorithm (SA). We analyze the transient, steady state and tracking performance of the introduced algorithms and demonstrate the match of the theoretical analyzes and simulation results. We show the extended stability bound of the LMLS algorithm and analyze the robustness of the LLAD algorithm against impulsive interferences. Finally, we demonstrate the performance of our algorithms in different scenarios through numerical examples.Comment: Submitted to IEEE Transactions on Signal Processin

Total Synthesis of 6,7-Dimethyl-N-Methyl Aziridinomitosene

Mitomycin C (MC) is a naturally occurring antitumor agent isolated from a soil bacterium. MC is effective against solid hypoxic tumors that respond poorly to radiotherapy, such as colorectal, gastric, and lung tumors. Also, it has a role in the treatment of bladder, head and neck, and non-small cell lung cancers in combination with other chemotherapeutic. MC and other members of the mitomycin family of antitumor agents fight cancer by forming DNA interstrand crosslinks (ICLs), which leads to apoptosis. In order to form ICLs, MC requires a reductive activation step that produces reactive oxygen species. This activation step is proposed to lead to adverse side effects, such as myelosuppression and hemolytic uremic syndrome. Aziridinomitosenes (AZMs) are structurally related to MC and are believed to form during in vivo reduction of MC. AZMs are relatively stable but are more sensitive than the parent mitomycins due to an activated aziridine ring. Consequently, AZMs do not require the reductive activation step in order to alkylate DNA. The purpose of this work is to synthesize and study an AZM that is substituted with methyl groups at two potential electrophilic sites. It is hypothesized that certain synthetic AZMs crosslink DNA under non-reductive conditions as a result of a nucleophilic activation sequence involving the quinone ring. To test this hypothesis, analogs were prepared that would either reduce the rate of the activation step or prevent it from occurring. The synthetic route starts with commercially available reagents to form an oxazole, followed by the addition of a protected aldehyde that is converted to the required aziridine ring via a Mitsunobu reaction. Once the aziridine ring is formed, all of the reaction conditions must be conducted using mild conditions in order to prevent ring-opening. The completion of the synthesis and formation of the tetracyclic core was achieved by performing an oxazolium salt/azomethine ylide [3+2] cycloaddition sequence. This sequence was conducted multiple times, and the highest yield obtained was 44%. The final steps were the most challenging, requiring several transformations to accomplish a deprotection and oxidation to give a diketone that was oxidized to a quinone. Finally, the carbamate was attached in two steps using FmocNCO to yield the desired AZM product in an overall yield of 0.04% from the starting diol over the 22 step reaction sequence. The stability of the AZM was tested in buffered methanolic solutions, and the results were compared to other aziridinomitosenes. While unsubstituted AZMs decompose in basic solutions, the C6/C7 dimethyl AZM showed high stability under these conditions

Stochastic Subgradient Algorithms for Strongly Convex Optimization over Distributed Networks

We study diffusion and consensus based optimization of a sum of unknown convex objective functions over distributed networks. The only access to these functions is through stochastic gradient oracles, each of which is only available at a different node, and a limited number of gradient oracle calls is allowed at each node. In this framework, we introduce a convex optimization algorithm based on the stochastic gradient descent (SGD) updates. Particularly, we use a carefully designed time-dependent weighted averaging of the SGD iterates, which yields a convergence rate of $O\left(\frac{N\sqrt{N}}{T}\right)$ after $T$ gradient updates for each node on a network of $N$ nodes. We then show that after $T$ gradient oracle calls, the average SGD iterate achieves a mean square deviation (MSD) of $O\left(\frac{\sqrt{N}}{T}\right)$. This rate of convergence is optimal as it matches the performance lower bound up to constant terms. Similar to the SGD algorithm, the computational complexity of the proposed algorithm also scales linearly with the dimensionality of the data. Furthermore, the communication load of the proposed method is the same as the communication load of the SGD algorithm. Thus, the proposed algorithm is highly efficient in terms of complexity and communication load. We illustrate the merits of the algorithm with respect to the state-of-art methods over benchmark real life data sets and widely studied network topologies

Ultrastructural description of the corpora allata of Pimpla turionellae L. (Hymenoptera: Ichneumonidae)

The corpora allata, are endocrine glands which produced juvenile hormone. In this study, corpora allata of adult females of Pimpla turionellae were examined ultrastructurally by using the transmission electron microscopy. The gland is surrounded with thick fibrous capsule that penetrates into the gland as a stromatal ramification. The ultrastructure of gland cells had the same characteristic of proteinsecreting cells. These cells had oval shaped nuclei, numerous granules, lysosomes, mitochondria and vacuoles. There are granules of electron-dense, electron-modarate and electron-lucent. These granules are actually membrane-limited secretory vesicles which are filled with the proteinaceous hormone produced by the gland cells. Microtubules and mitochondria were observed in the cytoplasm of axons of neurosecretory cells found among the gland cells.Key words: Hymenoptera, Pimpla turionellae, corpora allata, ultrastructure, transmission electron microscopy

Ultimate Load of Different Types of Reinforced Self-Compacting Concrete Columns Attacked by Sulphate

In this study, the effects of the partial immersion of sulphate attack on the ultimate load capacity of reinforced self-compacting concrete (SCC) columns and the sulphate attack resistance improvement using silica fume, steel fibres, and the combination of silica fume and steel fibres were assessed. Twelve short circular self-compacting reinforced concrete columns (0.150 m in diameter and 0.7 m long) were cast and divided into groups according to (1) the three acid-attack groups. The first group was tested without an acid attack (control). The second group was tested after 1 month of exposure to 2% acid. The final group was tested after 1 month of exposure to 4% acid and was then (2) subdivided according to the type of casted concrete. The first group was cast with SCC. The second group was cast with SCC and silica fume (0.1% of the cement weight). The third group was cast with SCC and 1% volume fraction steel fibres. The fourth group was cast with SCC silica fume and 1% volume fraction steel fibre. All columns were tested by axial loading. The ultimate load was increased by 42% with silica fume, 190% with steel fibres, and 238% with silica fume and steel fibres. Exposure to 2% and 4% acid reduced the ultimate loads of the columns casted with SCC by 23% and 47%, the columns casted with SCC and silica fume by 34% and 37%, the columns casted with SCC and steel fibres by 69% and 78%, and the columns casted with SCC, silica fume, and steel fibres by 72% and 79%, respectively. Based on the results, using silica fumes improved sulphate resistance, and using steel fibres enhanced sulphate resistance at an acceptable ratio. Furthermore, the mix with silica fume and steel fibres improved sulphate resistance at a good ratio. We encountered several problems in this study. The partial immersion of sulphate affected the strain in both concrete and steel. Future studies using different immersion ratios are recommended. Doi: 10.28991/CEJ-2022-08-10-04 Full Text: PD

Quantitative assessment of people-oriented forestry in Bangladesh: A case study in the Tangail forest division

ArticleJOURNAL OF ENVIRONMENTAL MANAGEMENT. 88(1): 83-92 (2008)journal articl