Nitrogen cycling and bacterial production

I. Bacterial abundance and production in Nueces and Guadalupe Estuaries, Texas -- II. Ammonium regeneration and utilization in Nueces Estuary, Texas -- III. Comparison of benthic ammonium flux with ammonium regeneration in the water column of Nueces and Guadalupe Estuaries, Texas -- IV. Denitrification in Nueces and Guadalupe Estuaries, Texas -- V. Ammonium regeneration and utilization in Guadalupe Estuary, Texas.Marine Scienc

DNA Steganalysis Using Deep Recurrent Neural Networks

Recent advances in next-generation sequencing technologies have facilitated the use of deoxyribonucleic acid (DNA) as a novel covert channels in steganography. There are various methods that exist in other domains to detect hidden messages in conventional covert channels. However, they have not been applied to DNA steganography. The current most common detection approaches, namely frequency analysis-based methods, often overlook important signals when directly applied to DNA steganography because those methods depend on the distribution of the number of sequence characters. To address this limitation, we propose a general sequence learning-based DNA steganalysis framework. The proposed approach learns the intrinsic distribution of coding and non-coding sequences and detects hidden messages by exploiting distribution variations after hiding these messages. Using deep recurrent neural networks (RNNs), our framework identifies the distribution variations by using the classification score to predict whether a sequence is to be a coding or non-coding sequence. We compare our proposed method to various existing methods and biological sequence analysis methods implemented on top of our framework. According to our experimental results, our approach delivers a robust detection performance compared to other tools

Synthesis of Two- and Three-Dimensional Carbon-Based Materials and Their Applications

Department of Energy EngineeringDue to abundant carbon reserves (15th most element in the earth???s crust) and light weight advantage, carbon based materials have been studied to replace rare and expansive inorganic materials in energy materials. Since the discovery of graphene, two dimensional structure, in 2004, two dimensional carbon materials have attracted the attention of researchers from around the globe. Keeping in view the importance of carbon materials, we first produced edge-selective functionalized graphene (EFG) for the production of large-area uniform graphene film for transparent and flexible electrode and transistor by top-down method from graphite to graphene. The resultant graphene films show ambipolar transport properties with sheet resistances of 0.52-3.11 k??/sq at 63-90% optical transmittance. EFG allows solution processing methods for the scalable production of electrically conductive, optically transparent, and mechanically robust flexible graphene films for use in practice. Secondary, we designed and synthesized two dimensional benzimidazole based network polymer for counter electrode in dye-sensitized solar cell (DSSC) to replace platinum. We confirm the effect of thermal annealing and additives of iron from T-HPBI for electrocatalytic activity from the symmetrical dummy cell with two identical electrodes. Furthermore, we also designed and synthesized three-dimensional polymer through solid-state reaction without catalyst at low-temperature for solid sorbent for CO2 capture. The reaction is triggered by metastable crystal lattice energy below its crystal melting temperature. The driving force for the reaction is systematically studied with single-crystal X-ray diffraction and differential scanning calorimetry.ope

Denitrification and Oxygen Consumption in Sediments of Two South Texas Estuaries

Spatial and temporal variations in rates of denitrification and oxygen consumption were measured in sediments of the Nueces and Guadalupe Estuaries in southern Texas, USA. Denitrification rates varied from 4.0 to 71.1 µmol N2 m-2 h-1 in the Nueces Estuary and from 4.6 to 34.7 µmol N2 m-2 h-1 in the Guadalupe Estuary. Denitrification accounted for 29 to 80% of total benthic N flux in the study areas. Oxygen consumption rates ranged from 176 to 818 µmol O2 m-2 h-1 in Nueces Estuary and from 208 to 550 µmol O2 m-2 h-1 in Guadalupe Estuary. In both estuaries denitrification and oxygen consumption rates were generally higher in the upper estuaries where the porosity and organic matter contents of sediments were typically highest. Among 3 measurements in different seasons, the lowest denitrification and oxygen consumption rates were usually observed during winter. Chemical oxygen consumption, as measured using formalin-killed controls, was about 50 % of the total oxygen consumption. A considerable portion (ca 50 %,) of biological oxygen consumption was attributed to nitrification in sediments. We estimated that carbon mineralization by denitrifiers was as much as 40 to 179% of that by aerobic heterotrophs. In the Guadalupe Estuary, denitrification removed about 38 % of the measured inputs of organic and inorganic nitrogen. In the Nueces Estuary, the amount of nitrogen removed by denitrification was ca 2 times greater than the measured nitrogen inputs from the Nueces River and precipitation, suggesting that unmeasured anthropogenic inputs along the perimeter of the estuary were very important for maintaining nitrogen balance

Empty Squares in Arbitrary Orientation Among Points

This paper studies empty squares in arbitrary orientation among a set $P$ of $n$ points in the plane. We prove that the number of empty squares with four contact pairs is between $\Omega(n)$ and $O(n^2)$, and that these bounds are tight, provided $P$ is in a certain general position. A contact pair of a square is a pair of a point $p\in P$ and a side $\ell$ of the square with $p\in \ell$. The upper bound $O(n^2)$ also applies to the number of empty squares with four contact points, while we construct a point set among which there is no square of four contact points. These combinatorial results are based on new observations on the $L_\infty$ Voronoi diagram with the axes rotated and its close connection to empty squares in arbitrary orientation. We then present an algorithm that maintains a combinatorial structure of the $L_\infty$ Voronoi diagram of $P$, while the axes of the plane continuously rotates by $90$ degrees, and simultaneously reports all empty squares with four contact pairs among $P$ in an output-sensitive way within $O(s\log n)$ time and $O(n)$ space, where $s$ denotes the number of reported squares. Several new algorithmic results are also obtained: a largest empty square among $P$ and a square annulus of minimum width or minimum area that encloses $P$ over all orientations can be computed in worst-case $O(n^2 \log n)$ time.Comment: 39 pages, 11 figure