Improving EFL Learners Language Written Production Using Subtitled Videos

English as a Foreign Language (EFL) Learners tend to produce their speech or written production as they are associated with what they see and what they hear. So, they are able and desired to give comment spontaneously after watching and listening to them. Producing written language can, as a matter of fact, be detected from learners\u27 fluency, accuracy and complexity. This article endeavors to elaborate written language production done by university students by using English subtitled videos. Two intact groups were assigned to accomplish two different tasks; that is, one group watched the video with subtitle and the other one without subtitle. The result of the study reveals that learners who carry out the tasks of watching video with subtitle improve their ability in written production in terms of fluency and accuracy regardless to complexity

Isoperimetric Inequalities in Carnot Groups

The isoperimetric problem is a very classical problem whose history dates back to more than two thousand years ago. Roughly speaking, the isoperimetric problem is to determine the largest possible area enclosed by a closed curve which has a specified length. In this thesis, we give proofs of a few theorems on isoperimetric inequalities in Carnot groups. Specifically, for a free nilpotent Carnot group $G$ of step 2, we show the filling function $FA_0(r)$ of the central product G\cp G has a quadratic isoperimetric inequality. Moreover, for Carnot group $G$ of step 2 which satisfies quadratic isoperimetric inequality, we show the filling function of its quotient group satisfies \fa \preceq r^2\log r. As a result of two previous theorems, we prove the following result: For a Carnot group $G$ of step $2$, the filling function of the central product $G\times_z G$ satisfies $FA_0 (r) \preceq r^2\log (r)$

Atmospheric Oxidation Mechanism of Phenol Initiated by OH Radical

The gas-phase oxidation mechanism of phenol initiated by OH radical was investigated using DFT and ab initio calculations. The initiation of the reaction is dominated by OH addition to <i>ortho</i>-position, forming P2, which subsequently combines with O₂ at the <i>ipso</i>-position to form P2-1-OO adduct. A concerted HO₂ elimination process from P2-1-OO was found to be much faster than the common ring closure to bicyclic intermediates. The HO₂ elimination process from P2-1-OO forms 2-hydroxy-3,5-cyclohexadienone (<b>HCH</b>) as the main product and is also responsible for the experimental fact that the rate constants for reaction between P2 and O₂ are about 2 orders of magnitude higher than those between other aromatic–OH adducts and O₂. It was speculated that <b>HCH</b> would isomerize to catechol, which is thermodynamically more stable than <b>HCH</b> and was the experimentally observed main product, possibly through heterogeneous processes. Reaction of P2 with NO₂ proceeded by addition to form P2-<i>n</i>-NO₂ (<i>n</i> = 1, 3, 5), followed by HONO elimination from P2-1/3-NO₂ to form catechol. The barriers for HONO elimination and catechol formation are below the separate reactants P2 and NO₂, being consistent with the experimental observation of catechol in the absence of O₂, while H₂O elimination from P2-1/3-NO₂ to form 2-nitrophenol (2NP) is hindered by high barriers. The most likely pathway for 2NP is the reaction of phenoxy radical and NO₂

Atmospheric Oxidation Mechanism of Furfural Initiated by Hydroxyl Radicals

Furfural is emitted into the atmosphere because of its potential applications as an intermediate to alkane fuels from biomass, industrial usages, and biomass burning. The kinetic and mechanistic information on the furfural chemistry is necessary to assess the fate of furfural in the atmosphere and its impact on the air quality. Here we studied the atmospheric oxidation mechanisms of furfural initiated by the OH radicals using quantum chemistry and kinetic calculations. The reaction of OH and furfural was initiated mainly by OH additions to C₂ and C₅ positions, forming R2 and R5 adducts, which could undergo rapid ring-breakage to form R2B and R5B, respectively. Our calculations showed that these intermediate radicals reacted rather slowly with O₂ under the atmospheric conditions because the additions of O₂ to these radicals are only slightly exothermic and highly reversible. Alternatively, these radicals would react directly with O₃, NO₂, HO₂/RO₂, etc. Namely, the atmospheric oxidation of furfural would unlikely result in ozone formation. Under typical atmospheric conditions, the main products in OH-initiated furfural oxidation include 2-oxo-3-pentene-1,5-dialdehyde, 5-hydroxy-2­(5<i>H</i>)-furanone, 4-oxo-2- butenoic acid, and 2,5-furandione. These compounds will likely stay in the gas phase and are subject to further photo-oxidation

Atmospheric Oxidation Mechanism of <i>m</i>‑Xylene Initiated by OH Radical

The atmospheric oxidation mechanism of <i>m</i>-xylene (<i>m</i>X) initiated by the OH radical is investigated at M06-2X and ROCBS-QB3 levels, coupled with reaction kinetics calculations by using transition state theory and unimolecular RRKM-ME theory. The calculations show that the reaction between OH and <i>m</i>X is dominated by OH addition to the C₂ and C₄ positions, forming adducts <i>m</i>X–2-OH (R2) and <i>m</i>X–4-OH (R4). In the atmosphere, R2 and R4 react with O₂ by irreversible H-abstraction to dimethylphenols or by reversible additions to bicyclic radical intermediates, which would recombine again with O₂ to form bicyclic peroxy radicals, to bicyclic alkoxyl radicals by reacting with NO or HO₂, and eventually to final products such as glyoxal, methylglyoxal, and their coproducts. The effects of reaction pressure and temperature are explored by RRKM-ME calculations. A mechanism at 298 K is proposed on the basis of current predictions and previous experimental and modeling results. The predicted product yields support the values in the SAPRC mechanism, even though the predicted yield of 1.0% for glyoxal is lower than the value of ∼11% from the experimental measurements

Mechanism of Gas-Phase Ozonolysis of β‑Myrcene in the Atmosphere

β-Myrcene is one of the major monoterpenes in the atmosphere. Ozonolysis is one of the oxidation removal processes for myrcene in the atmosphere during the daytime. In this study, the mechanism of myrcene ozonolysis is studied using high-level quantum chemistry calculations and kinetic calculations. The reaction starts with the formation of primary ozonides (POZs), which decompose to three primary product channels as 4-vinyl-4-pentenal (<b>4V4P</b>) + (CH₃)₂OO and two Criegee intermediates (<i>anti</i>- and <i>syn</i>-My-CIs) + acetone with branching ratios of 0.73, 0.23, and 0.04, respectively. The Criegee intermediates (CIs) are formed with high excitation, and they could either isomerize promptly or be thermalized to stabilized CIs (sCIs) at fractions of 0.39, 0.23, and 0.25 for (CH₃)₂COO*, <i>anti</i>-My-CI*, and <i>syn</i>-My-CI*. For stabilized My-CIs, <i>syn</i>-My-CI would undergo unimolecular H-migration to a vinyl hydroperoxide (VHP), which decomposes readily to OH radical and a vinoxy-type radical, while <i>anti</i>-My-CI would most likely react with water vapor or cyclize to a bicyclic compound when relative humidity is low. Reaction of My-CIs with SO₂ is important only for conditions of low temperatures (<273 K) and low relative humidity. The predicted yields of 0.73 and 0.27 for <b>4V4P</b> and acetone agree reasonably with previous experimental measurements

New Mechanism for the Atmospheric Oxidation of Dimethyl Sulfide. The Importance of Intramolecular Hydrogen Shift in a CH₃SCH₂OO Radical

Theoretical study has been carried out on the fate of methylthiomethylperoxy radical (CH₃SCH₂OO, <b>MSP</b>) in the atmosphere. The intramolecular H-shift followed by recombination with O₂, <b>MSP</b> → CH₂SCH₂OOH → OOCH₂SCH₂OOH (<b>MSPO</b>_<b>2</b>), is found to be fast enough, that is, 2.1 s^–1 at 293 K, to compete with and even surpass the possible bimolecular reactions of <b>MSP</b> with NO_<i>x</i>, HO₂, and RO₂ in the remote marine atmosphere. <b>MSPO</b>_<b>2</b> would also undergo another intramolecular H-shift and decompose to the most important intermediate HOOCH₂SCHO instead of the CH₃SCH₂O radical. HOOCH₂SCHO would be further oxidized via the route as HOOCH₂SCO (by OH radical) → HOOCH₂S (by decomposition) → HOOCH₂SO (by O₃ or NO₂) → HOOCH₂SO₂ (by O₃ and NO₂) → OH + CH₂O + SO₂ (by decomposition). Our calculations suggest a drastically different oxidation mechanism for dimethyl sulfide (CH₃SCH₃, DMS) in the remote marine atmosphere

Image_1_Impacts of different fencing periods and grazing intensities on insect diversity in the desert steppe in Inner Mongolia.tif

For the past several decades, both species biodiversity and productivity of desert steppe have been reduced due to excessive use and climate factors. To counteract this, Chinese government has supported large-scale grassland ecological restoration programs since the year 2000. The policy needs a standard for the evaluation of the effects of such restorative measures on the grasslands after decades. Grassland insect diversity plays an important role in the maintenance of plant species and functional diversity. To understand the relation of grazing management and insect diversity, we use a complete two factor design, two fencing periods (3 or 7 years) and three grazing intensities (0, 6, or 12 sheep per ha), to examine the response of the insect diversity to fencing and grazing in desert steppe. We found almost no significant differences in either plant or insect species diversity between the sites fenced for 3 and 7 years, as the pressure of grazing increased, insect diversity decreased to a greater extent at 7-year enclosure sites than at 3-year sites. We recommend the most suitable grazing intensity for the sustainability of biodiversity of the desert steppe in Inner Mongolia is light grazing (8 sheep/ha 0.5 yr−1), and the most suitable fencing period is three years, which suggest that policies that remove livestock from the desert grassland for long periods (7 + years) are not beneficial for maintaining insect diversity, and heavy grazing lead ecological environment weaker and insect diversity decreasing. Thus, periodic livestock grazing is important in the design of management actions to preserve biodiversity.</p

Image_3_Impacts of different fencing periods and grazing intensities on insect diversity in the desert steppe in Inner Mongolia.tif

For the past several decades, both species biodiversity and productivity of desert steppe have been reduced due to excessive use and climate factors. To counteract this, Chinese government has supported large-scale grassland ecological restoration programs since the year 2000. The policy needs a standard for the evaluation of the effects of such restorative measures on the grasslands after decades. Grassland insect diversity plays an important role in the maintenance of plant species and functional diversity. To understand the relation of grazing management and insect diversity, we use a complete two factor design, two fencing periods (3 or 7 years) and three grazing intensities (0, 6, or 12 sheep per ha), to examine the response of the insect diversity to fencing and grazing in desert steppe. We found almost no significant differences in either plant or insect species diversity between the sites fenced for 3 and 7 years, as the pressure of grazing increased, insect diversity decreased to a greater extent at 7-year enclosure sites than at 3-year sites. We recommend the most suitable grazing intensity for the sustainability of biodiversity of the desert steppe in Inner Mongolia is light grazing (8 sheep/ha 0.5 yr−1), and the most suitable fencing period is three years, which suggest that policies that remove livestock from the desert grassland for long periods (7 + years) are not beneficial for maintaining insect diversity, and heavy grazing lead ecological environment weaker and insect diversity decreasing. Thus, periodic livestock grazing is important in the design of management actions to preserve biodiversity.</p

Image_2_Impacts of different fencing periods and grazing intensities on insect diversity in the desert steppe in Inner Mongolia.tif

For the past several decades, both species biodiversity and productivity of desert steppe have been reduced due to excessive use and climate factors. To counteract this, Chinese government has supported large-scale grassland ecological restoration programs since the year 2000. The policy needs a standard for the evaluation of the effects of such restorative measures on the grasslands after decades. Grassland insect diversity plays an important role in the maintenance of plant species and functional diversity. To understand the relation of grazing management and insect diversity, we use a complete two factor design, two fencing periods (3 or 7 years) and three grazing intensities (0, 6, or 12 sheep per ha), to examine the response of the insect diversity to fencing and grazing in desert steppe. We found almost no significant differences in either plant or insect species diversity between the sites fenced for 3 and 7 years, as the pressure of grazing increased, insect diversity decreased to a greater extent at 7-year enclosure sites than at 3-year sites. We recommend the most suitable grazing intensity for the sustainability of biodiversity of the desert steppe in Inner Mongolia is light grazing (8 sheep/ha 0.5 yr−1), and the most suitable fencing period is three years, which suggest that policies that remove livestock from the desert grassland for long periods (7 + years) are not beneficial for maintaining insect diversity, and heavy grazing lead ecological environment weaker and insect diversity decreasing. Thus, periodic livestock grazing is important in the design of management actions to preserve biodiversity.</p