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Polycyclic aromatic hydrocarbons (PAHs) are among the most widely spread pollutants in the environment including the agricultural soil. PAH degradation by indigenous bacteria is an effective and economical means to remove these pollutants from the environment. Here, we report a bacterial consortium (Pdy-1) isolated from paddy rice soil in northern Japan able to degrade polycyclic aromatic hydrocarbons (PAHs) at high rates. Pdy-1 was incubated with a mixture of PAH compounds (fluorene, phenanthrene, and pyrene) in Bushnell Haas Medium at a final concentration of 100mg/L each. PDY-1 degraded 100% of fluorene, 95% of phenanthrene, and 52% of pyrene in 5 days. Phenanthrene and pyrene were completely degraded at 10 d and 15 d, respectively. Cloning of the 16S rRNA gene revealed that the consortium was composed of 40% Achromobacter and 7% each of Castelaniella, Rhodanobacter, and Hypomicrobium. Comamonas, Ferrovibrio, Terrimonas, Bordetella, Rhizobium, and Pseudonocardia were also detected. PCR-DGGE showed the dynamics of the consortium during the incubation period. Real-time PCR revealed that PAH degrading genes such as the gram-positive ring dihydroxylating genes (PAH-RDH) and pyrene dioxygenase (nidA) were most abundant at day 5 when the rapid biodegradation of the PAHs was observed. This study improves our understanding on dynamics and characteristics of an effective PAH-degrading bacterial consortium from paddy rice soil. [ABSTRACT FROM AUTHOR]

Arsenic (As) hyperaccumulator Pteris ferns are renowned for their capacity to accumulate As and have been used to remediate As-contaminated environmental. However, there is less information on how they perform under low temperature though it is important for practical phytoremediation. The purpose of this study was to identify the effect of temperature on As accumulation by three As hyperaccumulators, Pteris multifida, Pteris cretica and Pteris vittata. Ferns were cultured with 5 mg/L As addition under 25 °C to 5 °C for 15 days. The results showed that dropping of temperatures reduced As accumulation by P. vittata moderately but not P. multifida and P. cretica until 10 °C. At 5 °C, all ferns discontinued As accumulation, and the morphology showed necrosis in P. vittata, wherein P. multifida and P. cretica kept healthy. The As distribution showed that As was mainly accumulated in fronds, while P. multifida stored partial As in its root. Both translocation factor and As efflux showed that temperate zone ferns manage As more strictly as compared to P. vittata. Our findings demonstrated that temperature should be considered when applying Pteris ferns for As phytoremediation, and P. multifida could be the most suitable fern for treating As-contaminated water in temperate zone area. [ABSTRACT FROM AUTHOR]

This paper investigates the comparability between the video-conferencing and face-to-face modes of the IELTS Speaking Test in terms of scores and language functions generated by test-takers. Data were collected from 10 trained IELTS examiners and 99 test-takers who took two speaking tests under face-to-face and video-conferencing conditions. Many-facet Rasch Model (MFRM) analysis of test scores indicated that the delivery mode did not make any meaningful difference to test-takers' scores. An examination of language functions revealed that both modes equally elicited the same language functions except asking for clarification. More test-takers made clarification requests in the video-conferencing mode (63.3%) than in the face-to-face mode (26.7%). Drawing on the findings, as well as practical implications, we extend emerging thinking about video-conferencing speaking assessment and the associated features of this modality in its own right. [ABSTRACT FROM AUTHOR]

This mixed methods study compared IELTS examiners' scores when assessing spoken performances under live and two 'non-live' testing conditions using audio and video recordings. Six IELTS examiners assessed 36 test-takers' performances under the live, audio, and video rating conditions. Scores in the three rating modes were calibrated using the many-facet Rasch model (MFRM). For all three modes, examiners provided written justifications for their ratings, and verbal reports were also collected to gain insights into examiner perceptions towards performance under the audio and video conditions. Results showed that, for all rating criteria, audio ratings were significantly lower than live and video ratings. Examiners noticed more negative performance features under the two non-live rating conditions, compared to the live condition. However, richer information about test-taker performance in the video mode appeared to cause raters to rely less on such negative evidence than audio raters when awarding scores. Verbal report data showed that having visual information in the video-rating mode helped examiners to understand what the test-takers were saying, to comprehend better what test-takers were communicating using non-verbal means, and to understand with greater confidence the source of test-takers' hesitation, pauses, and awkwardness. [ABSTRACT FROM AUTHOR]

The main threats to the environment from heavy metals are associated with arsenic (As), lead (Pb) and cadmium (Cd). In this study, the potential of Pteris multifida for removing As, Pb and Cd from hydroponic solution and pot soil was evaluated for the first time. Short-term (5 day) experiments were conducted to assess phytofiltration efficiency of temperate zone fern P. multifida and to compare it with mostly studied tropical zone fern P. vittata. Within 5 days, P. multifida accumulated 33% of As(III), whereas P. vittata could not accumulate that most toxic arsenic species As(III) at all. Long-term hydroponic results showed that 90% of Pb, 50% of As and 36% of Cd were removed by P. multifida. Concentration of As in the frond (22 mg/kg dw) was comparatively higher than other parts of plant and significantly higher concentration of Cd and Pb were stored in root and rhizome. Pot soil experiment of P multifida confirmed the comparative uptake and translocation of As(V), Pb and Cd from soil. Therefore, from the assessment of heavy metal accumulation capacity, translocation and healthy survival for long time, P. multifida was identified as an excellent species for the treatment of multi-metal contaminated water and soil. [ABSTRACT FROM AUTHOR]

This research explores how Internet-based video-conferencing technology can be used to deliver and conduct a speaking test, and what similarities and differences can be discerned between the standard and computer-mediated face-to-face modes. The context of the study is a high-stakes speaking test, and the motivation for the research is the need for test providers to keep under constant review the extent to which their tests are accessible and fair to a wide constituency of test takers. The study examines test-takers’ scores and linguistic output, and examiners’ test administration and rating behaviors across the two modes. A convergent parallel mixed-methods research design was used, analyzing test-takers’ scores and language functions elicited, examiners’ written comments, feedback questionnaires and verbal reports, as well as observation notes taken by researchers. While the two delivery modes generated similar test score outcomes, some differences were observed in test-takers’ functional output and the behavior of examiners who served as both raters and interlocutors. [ABSTRACT FROM PUBLISHER]

The constructs of complexity, accuracy and fluency (CAF) have been used extensively to investigate learner performance on second language tasks. However, a serious concern is that the variables used to measure these constructs are sometimes used conventionally without any empirical justification. It is crucial for researchers to understand how results might be different depending on which measurements are used, and accordingly, choose the most appropriate variables for their research aims. The first strand of this article examines the variables conventionally used to measure syntactic complexity in order to identify which may be the best indicators of different proficiency levels, following suggestions by Norris and Ortega. The second strand compares the three variables used to measure accuracy in order to identify which one is most valid. The data analysed were spoken performances by 64 Japanese EFL students on two picture-based narrative tasks, which were rated at Common European Framework of Reference for Languages (CEFR) A2 to B2 according to Rasch-adjusted ratings by seven human judges. The tasks performed were very similar, but had different degrees of what Loschky and Bley-Vroman term ‘task-essentialness’ for subordinate clauses. It was found that the variables used to measure syntactic complexity yielded results that were not consistent with suggestions by Norris and Ortega. The variable found to be the most valid for measuring accuracy was errors per 100 words. Analysis of transcripts revealed that results were strongly influenced by the differing degrees of task-essentialness for subordination between the two tasks, as well as the spread of errors across different units of analysis. This implies that the characteristics of test tasks need to be carefully scrutinised, followed by careful piloting, in order to ensure greater validity and reliability in task-based research. [ABSTRACT FROM PUBLISHER]

On March 11, 2011, one of the negative effects of the tsunami phenomenon that devastated the Pacific coast of the Tohoku district in Japan was the deposition of a wide range of arsenic (As) contamination to the soil. To remediate such a huge area of contamination, phytoremediation byPteris vittata, an As-hyperaccumulator, was considered. To evaluate the efficacy of applyingP. vittatato the area, the salt tolerance ofP. vittataand the phytoextraction of As from soil samples were investigated. For the salt tolerance test, spore germination was considerably decreased at an NaCl level of more than 100 mM. At 200 mM, the gametophytes exhibited a morphological defect. Furthermore, the growth inhibition ofP. vittatawas observed with a salinity that corresponded to 66.2 mS/m of electric conductivity (EC) in the soil. A laboratory phytoremediation experiment was conducted using As-contaminated soils for 166 days.P. vittatagrew and accumulated As at 264 mg/kg-DW into the shoots. Consequently, the soluble As in the soil was evidently decreased. These results showed thatP. vittatawas applicable to the phytoremediation of As-contaminated soil with low salinity as with the contamination caused by the 2011 tsunami. [ABSTRACT FROM PUBLISHER]

The discovery of novel accumulating plants is useful for efficient phytoremediation due to the demands of various conditions of impacted sites such as land use, soil properties, concentration of pollutants, and climate. In the present study, we investigated foliar application or a field with highly bioavailable arsenic (As) to screen As-accumulating plants. Plants grown in the downstream of a hot springs area were analyzed for native As accumulation and As foliar application, and the rhizosphere soils were collected. The water-soluble As in the rhizosphere soils had a high average, 144 μg/kg, whereas total As was similar to normal soil in Japan. Among 34 herbaceous plants and 17 woody plants,Chelidonium majus var. asiaticumaccumulated a relatively high As level, 8.07 mg/kg DW (93.6% of As added), that was not revealed by native accumulation. In a further pot experiment,C. majusaccumulated a moderately high As level (314 mg/kg DW) in the roots but not in the shoot (30.1 mg/kg DW), and exhibited a low transfer factor (TF = 0.096). Thus, a foliar application would be a simple and high-throughput method to screen plants that accumulate and tolerate As.C. majuswould be useful as a tool for phytostabilization of As. [ABSTRACT FROM AUTHOR]

Mangroves constitute valuable coastal resources that are vulnerable to oil pollution. One of the major processes to remove oil from contaminated mangrove sediment is microbial degradation. A study on heavy oil- and hydrocarbon-degrading bacterial consortia from mangrove sediments in Okinawa, Japan was performed to evaluate their capacity to biodegrade and their microbial community composition. Surface sediment samples were obtained from mangrove sites in Okinawa (Teima, Oura, and Okukubi) and enriched with heavy oil as the sole carbon and energy source. The results revealed that all enriched microbial consortia degraded more than 20% of heavy oil in 21 days. The K1 consortium from Okukubi site showed the most extensive degradative capacity after 7 and 21 days. All consortia degraded more than 50% of hexadecane but had little ability to degrade polycyclic aromatic hydrocarbons (PAHs). The consortia were dominated byPseudomonasorBurkholderia.When incubated in the presence of hydrocarbon compounds, the active bacterial community shifted to favor the dominance ofPseudomonas. The K1 consortium was a superior degrader, demonstrating the highest ability to degrade aliphatic and aromatic hydrocarbon compounds; it was even able to degrade heavy oil at a concentration of 15%(w/v). The dominance and turn-over ofPseudomonasandBurkholderiain the consortia suggest an important ecological role for and relationship between these two genera in the mangrove sediments of Okinawa. [ABSTRACT FROM AUTHOR]