Natural source zone depletion of LNAPL: A critical review supporting modelling approaches

Natural source zone depletion (NSZD) of light non-aqueous phase liquids (LNAPLs) includes partitioning, transport and degradation of LNAPL components. NSZD is being considered as a site closure option during later stages of active remediation of LNAPL contaminated sites, and where LNAPL mass removal is limiting. To ensure NSZD meets compliance criteria and to design enhanced NSZD actions if required, residual risks posed by LNAPL and its long term behaviour require estimation. Prediction of long-term NSZD trends requires linking physicochemical partitioning and transport processes with bioprocesses at multiple scales within a modelling framework. Here we expand and build on the knowledge base of a recent review of NSZD, to establish the key processes and understanding required to model NSZD long term. We describe key challenges to our understanding, inclusive of the dominance of methanogenic or aerobic biodegradation processes, the potentially changeability of rates due to the weathering profile of LNAPL product types and ages, and linkages to underlying bioprocesses. We critically discuss different scales in subsurface simulation and modelling of NSZD. Focusing on processes at Darcy scale, 36 models addressing processes of importance to NSZD are investigated. We investigate the capabilities of models to accommodate more than 20 subsurface transport and transformation phenomena and present comparisons in several tables. We discuss the applicability of each group of models for specific site conditions

Effectiveness of Mobile Phones as Learning Aid among Senior High School Students

Mobile phone usage by students is beneficial and found to have a great impact on students learning. This study assessed the effectiveness of mobile phones as a learning aid among senior high school students. The assessment is based on the dimensions using Gavriel Salomon’s symbol system theory. The study used the descriptive method of research, respondents are randomly selected using the cluster sampling technique. The principal instrument used is the survey questionnaire and a face-to-face survey is conducted. The survey used the 5-point Likert scale. For inferential statistics, the independent t-test is employed to compare the means based on gender. Results yield that there is no significant difference in the scores for males and females in the dimensions such as content, connectivity, and cognitive abilities. There is a significant difference in the dimensions such as convenience and digital literacy. There is no significant difference in the scores for males and females for the overall assessment of the effectiveness of mobile phones as learning aid across dimensions. Gender has no moderating effect. Implications for future research on capability infrastructures both for teachers and students across levels addressing gaps in institutionalizing online education portals/ applications for Filipino learners

Genomics and transcriptomics yields a system-level view of the biology of the pathogen Naegleria fowleri

Background The opportunistic pathogen Naegleria fowleri establishes infection in the human brain, killing almost invariably within 2 weeks. The amoeba performs piece-meal ingestion, or trogocytosis, of brain material causing direct tissue damage and massive inflammation. The cellular basis distinguishing N. fowleri from other Naegleria species, which are all non-pathogenic, is not known. Yet, with the geographic range of N. fowleri advancing, potentially due to climate change, understanding how this pathogen invades and kills is both important and timely. Results Here, we report an -omics approach to understanding N. fowleri biology and infection at the system level. We sequenced two new strains of N. fowleri and performed a transcriptomic analysis of low- versus high-pathogenicity N. fowleri cultured in a mouse infection model. Comparative analysis provides an in-depth assessment of encoded protein complement between strains, finding high conservation. Molecular evolutionary analyses of multiple diverse cellular systems demonstrate that the N. fowleri genome encodes a similarly complete cellular repertoire to that found in free-living N. gruberi. From transcriptomics, neither stress responses nor traits conferred from lateral gene transfer are suggested as critical for pathogenicity. By contrast, cellular systems such as proteases, lysosomal machinery, and motility, together with metabolic reprogramming and novel N. fowleri proteins, are all implicated in facilitating pathogenicity within the host. Upregulation in mouse-passaged N. fowleri of genes associated with glutamate metabolism and ammonia transport suggests adaptation to available carbon sources in the central nervous system. Conclusions In-depth analysis of Naegleria genomes and transcriptomes provides a model of cellular systems involved in opportunistic pathogenicity, uncovering new angles to understanding the biology of a rare but highly fatal pathogen.publishedVersio

Characterization and genomic analysis of chromate resistant and reducing Bacillus cereus strain SJ1

<p>Abstract</p> <p>Background</p> <p>Chromium is a toxic heavy metal, which primarily exists in two inorganic forms, Cr(VI) and Cr(III). Chromate [Cr(VI)] is carcinogenic, mutational, and teratogenic due to its strong oxidizing nature. Biotransformation of Cr(VI) to less-toxic Cr(III) by chromate-resistant and reducing bacteria has offered an ecological and economical option for chromate detoxification and bioremediation. However, knowledge of the genetic determinants for chromate resistance and reduction has been limited so far. Our main aim was to investigate chromate resistance and reduction by <it>Bacillus cereus </it>SJ1, and to further study the underlying mechanisms at the molecular level using the obtained genome sequence.</p> <p>Results</p> <p><it>Bacillus cereus </it>SJ1 isolated from chromium-contaminated wastewater of a metal electroplating factory displayed high Cr(VI) resistance with a minimal inhibitory concentration (MIC) of 30 mM when induced with Cr(VI). A complete bacterial reduction of 1 mM Cr(VI) was achieved within 57 h. By genome sequence analysis, a putative chromate transport operon, <it>chrIA</it>1, and two additional <it>chrA </it>genes encoding putative chromate transporters that likely confer chromate resistance were identified. Furthermore, we also found an azoreductase gene <it>azoR </it>and four nitroreductase genes <it>nitR </it>possibly involved in chromate reduction. Using reverse transcription PCR (RT-PCR) technology, it was shown that expression of adjacent genes <it>chrA</it>1 and <it>chrI </it>was induced in response to Cr(VI) but expression of the other two chromate transporter genes <it>chrA</it>2 and <it>chrA</it>3 was constitutive. In contrast, chromate reduction was constitutive in both phenotypic and gene expression analyses. The presence of a resolvase gene upstream of <it>chrIA</it>1, an arsenic resistance operon and a gene encoding Tn7-like transposition proteins ABBCCCD downstream of <it>chrIA</it>1 in <it>B. cereus </it>SJ1 implied the possibility of recent horizontal gene transfer.</p> <p>Conclusion</p> <p>Our results indicate that expression of the chromate transporter gene <it>chrA</it>1 was inducible by Cr(VI) and most likely regulated by the putative transcriptional regulator ChrI. The bacterial Cr(VI)-resistant level was also inducible. The presence of an adjacent arsenic resistance gene cluster nearby the <it>chrIA</it>1 suggested that strong selective pressure by chromium and arsenic could cause bacterial horizontal gene transfer. Such events may favor the survival and increase the resistance level of <it>B. cereus </it>SJ1.</p

A service plan for Enchanted Kingdom

This paper is an in depth study about Enchanted Kingdom (EK), the first and only world-class theme park in the Philippines. EK began as a vision for Filipino families to enjoy a quality amusement place without having to go to other countries. EK has become a Filipino household name and one of Philippine\u27s Top Tourist attraction through the years. As a pioneer in the Theme Park/Amusement Park industry, this paper is a comprehensive service plan that will present research data gathered in terms of its industry study, company\u27s current brand situation, competitive analysis and current company strategies 8 P\u27s. It also discusses the trends in local tourism, a big factor that contributes to EKâ\u27s success

Development of a biomorphic and hyper-redundant caecilian based robots

This paper presents the development and design of a mobile multilink robot. Because of its multilink property, snake robots are appropriate in tight and hard to reach places. This is robot is intended to be deployed in such areas specifically in disaster rubbles. The robot is composed of 10 segments each of which has one degree of freedom. The robot is equipped with proximity sensors for obstacle detection and IMU for orientation sensing. In front of the robot, a wireless camera is attached so that the environment where the robot operates is viewed by the base controller. Experiments showed that the movement algorithm which follows the snake\u27s biological motion is successfully implemented with a maximum movement velocity of 70cm/s. The maximum climb height is 22cm. This study demonstrates the effectiveness of the snake robot in different terrain with obstacles and small obstacle gaps. © 2017 IEEE

Snake robot: Development of a serpentine robot for disaster-aid

The paper presents the development of a snake robot which can be used for disaster-aid to lessen the danger that the rescuers may encounter. The design of the snake robot considers the use of its own body segments for motion rather than using wheel. The use of segments enables the snake robot to move on uneven terrain. Servo motors are used for the movement of each joint and are powered by a lithium-polymer battery. Sensors and a head-mounted wireless pinhole camera will be used to monitor the vicinity and locate victims. An Arduino Pro Mini 328 is used as the microcontroller configured to receive commands from the base computer via wireless XBee transceivers. Its main movements will be used on a biological snakes rectilinear motion