High-resolution near-bottom vector magnetic anomalies over Raven Hydrothermal Field, Endeavour Segment, Juan de Fuca Ridge

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 7389–7403, doi:10.1002/2014JB011223.High-resolution, near-bottom vector magnetic data were collected by remotely operated vehicle Jason over the Raven hydrothermal vent field (47°57.3′N 129°5.75′W) located north of Main Endeavour vent field on the Endeavour segment of the Juan de Fuca Ridge. The survey was part of a comprehensive heat flow study of the Raven site using innovative thermal blanket technology to map the heat flux and crustal fluid pathways around a solitary hydrothermal vent field. Raven hydrothermal activity is presently located along the western axial valley wall, while additional inactive hydrothermal deposits are found to the NW on the upper rift valley wall. Magnetic inversion results show discrete areas of reduced magnetization associated with both active and inactive hydrothermal vent deposits that also show high conductive heat flow. Higher spatial variability in the heat flow patterns compared to the magnetization is consistent with the heat flow reflecting the currently active but ephemeral thermal environment of fluid flow, while crustal magnetization is representative of the static time-averaged effect of hydrothermal alteration. A general NW to SE trend in reduced magnetization across the Raven area correlates closely with the distribution of hydrothermal deposits and heat flux patterns and suggests that the fluid circulation system at depth is likely controlled by local crustal structure and magma chamber geometry. Magnetic gradient tensor components computed from vector magnetic data improve the resolution of the magnetic anomaly source and indicate that the hydrothermally altered zone directly beneath the Raven site is approximately 15 × 106 m3 in volume.This work was funded by the National Science Foundation under grant OCE-1037840 to Maurice Tivey and grant OCE-1037870 to H. Paul Johnson.2015-04-0

Quantitative estimate of heat flow from a mid-ocean ridge axial valley, Raven field, Juan de Fuca Ridge : observations and inferences

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 6841–6854, doi:10.1002/2014JB011086.A systematic heat flow survey using thermal blankets within the Endeavour segment of the Juan de Fuca Ridge axial valley provides quantitative estimates of the magnitude and distribution of conductive heat flow at a mid-ocean ridge, with the goal of testing current models of hydrothermal circulation present within newly formed oceanic crust. Thermal blankets were deployed covering an area of 700 by 450 m in the Raven Hydrothermal vent field area located 400 m north of the Main Endeavour hydrothermal field. A total of 176 successful blanket deployment sites measured heat flow values that ranged from 0 to 31 W m−2. Approximately 53% of the sites recorded values lower than 100 mW m−2, suggesting large areas of seawater recharge and advective extraction of lithospheric heat. High heat flow values were concentrated around relatively small “hot spots.” Integration of heat flow values over the Raven survey area gives an estimate of conductive heat output of 0.3 MW, an average of 0.95 W m−2, over the survey area. Fluid circulation cell dimensions and scaling equations allow calculation of a Rayleigh number of approximately 700 in Layer 2A. The close proximity of high and low heat flow areas, coupled with previous estimates of surficial seafloor permeability, argues for the presence of small-scale hydrothermal fluid circulation cells within the high-porosity uppermost crustal layer of the axial seafloor.This work has been funded by the National Science Foundation under grant OCE-1037870 and was supported under a National Science Foundation Graduate Research Fellowship to MSS2015-03-1

Analysis of the phenotypic variability of some varieties of durum wheat (Triticum durum Desf) to improve the efficiency of performance under the constraining conditions of semiarid environments

The experiment was conducted during three growing seasons and two planting dates. The cultivation site is placed at the ITGC Setif characterized by a semi-arid environment. The objective of the study is the analysis of phenotypic variability of traits measured for 15 varieties of durum wheat, through the average effects, to decline the ways, characters and varieties could play in favour of performance under the constraining semi-arid conditions. The year effect indicates that given the difficulty of predicting the performance enabled by years, it then makes sense to go straight for this performance within genotypes. Analysis of the effect genotype highlights characters connected to performance and is the Setifis variety that lends itself well. For the effect of sowing date, it is that early sowing promotes a better expression of the characteristics compared to late sowing.Keywords: Effect; genotype; year; date; variation; character

In vitro propagation of Acacia hybrid through alginate-encapsulated shoots and axillary buds

Seed collected from Acacia hybrid trees yields highly variable and poorly performing offspring and are not commonly used in regeneration. The present study described the incapsulation of Acacia hybrid shoots and axillary buds in the calcium alginate gel. The aim of the study was to evaluate the germination of the buds in vitro on the medium with different concentrations of plant growth regulator and; the performance of the germination under light and darkness. For encapsulation purposes, 3% sodium alginate (w/v) in the Murashige and Skoog (MS) free of calcium salt solution solvent were tested. While for complexation, 100 mM calcium chloride solutions (CaCl2.2H2O) were prepared in liquid MS medium. The encapsulated explants or the beads were cultured into the following media: Modified basal MS supplemented with 6-benzylaminopurine (BAP) ranging from 0 to 2.5 mg/L BAP. High germination rate (100%) was observed within five to eight days in all medium tested. Analysis of variance showed no significant difference in the ability of the synthetic seeds to germinate. This showed that the regeneration of shoots is possible by using basal MS only. It was observed that synthetic seeds needed sucrose more than plant growth regulator for its germination. They were also showing good regeneration and development under light condition.Key words: Acacia hybrid, synthetic seeds, encapsulation, germination, regeneration

Synthetic seed technology for encapsulation and regrowth of in vitro-derived Acacia hyrid shoot and axillary buds

In this study, various concentrations of sodium alginate solutions and calcium chloride solutions were tested in order to optimize the size, shape and texture of alginate synthetic seeds or beads for Acacia hybrid bud-sprouting. The shoot buds and axillary buds from in vitro Acacia hybrids, as explants were encapsulated with 2 to 5% sodium alginate (w/v) in the Murashige and Skoog (MS) free of calcium salt solution solvent and exposed to 25 to 100 mM calcium chloride solution (CaCl2.2H2O). Rounded beads were observed by the encapsulation with alginate 3% and exposed to 75 to 100 mM CaCl2.2H2O combinations and; the encapsulation with alginate 4 to 5% and exposed to any CaCl2.2H2O combinations. The produced synthetic seeds were then tested on the plantlets regeneration ability. The germination rate was within 73.3 to 100% in the duration of 6 to 20 days. It showed that encapsulation at any alginate concentrations and exposed to any of the CaCl2.2H2O concentrations, gave high germination frequency. These plantlets could then be used as the source of explants for the subsequent experiments. The synthetic seeds have the possibility of being an alternative planting material meant for forestry sector in the future, especially for the highly demanded species.Key word: Acacia hybrid, synthetic seeds, encapsulation, alternative planting material

Manganese pigmented anodized copper as solar selective absorber

The study concerns the optical and structural properties of layers obtained by a new efficient surface treatment totally free of chromium species. The process is made up of an anodic oxidation of copper in an alkaline solution followed by an alkaline potassium permanganate dipping post-treatment. Coatings, obtained at the lab and pilot scales, are stable up to 220 °C in air and vacuum, present low emissivity (0.14 at 70 °C) and high solar absorptivity (0.96), i.e. a suitable thermal efficiency (0.84 at 70 °C)

Effect of toroidal field ripple on plasma rotation in JET

Dedicated experiments on TF ripple effects on the performance of tokamak plasmas have been carried out at JET. The TF ripple was found to have a profound effect on the plasma rotation. The central Mach number, M, defined as the ratio of the rotation velocity and the thermal velocity, was found to drop as a function of TF ripple amplitude (3) from an average value of M = 0.40-0.55 for operations at the standard JET ripple of 6 = 0.08% to M = 0.25-0.40 for 6 = 0.5% and M = 0.1-0.3 for delta = 1%. TF ripple effects should be considered when estimating the plasma rotation in ITER. With standard co-current injection of neutral beam injection (NBI), plasmas were found to rotate in the co-current direction. However, for higher TF ripple amplitudes (delta similar to 1%) an area of counter rotation developed at the edge of the plasma, while the core kept its co-rotation. The edge counter rotation was found to depend, besides on the TF ripple amplitude, on the edge temperature. The observed reduction of toroidal plasma rotation with increasing TF ripple could partly be explained by TF ripple induced losses of energetic ions, injected by NBI. However, the calculated torque due to these losses was insufficient to explain the observed counter rotation and its scaling with edge parameters. It is suggested that additional TF ripple induced losses of thermal ions contribute to this effect

The interaction of cadmium and selenium in horse kidney cortex in relation to histopathological changes

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Perspectives of Science Teachers in Sultanate of Oman for Grades five to eight about the Effectiveness of the application of “Google Classroom Platform” in Providing Students with Self-Learning and Problem-Solving Skills

ملخص: هدفت هذه الدراسة إلى رصد تصوّرات معلمي العلوم، للصفوف من الخامس إلى الثامن، لفاعلية تطبيق منصة جوجل كلاس روم (Google Classroom)، في اكتساب الطلبة مهارات التعلّم الذاتي وحلّ المشكلات. اشتملت عينة الدراسة على (104) معلماً، و(293) معلمة، في ثماني محافظات تعليمية في سلطنة عُمان، ولتحقيق أهداف الدراسة، تبنّت الدراسة المنهج الوصفي، من خلال بناء مقياسٍ مجزء إلى محورين رئيسين، هما: مهارات التعلّم الذاتي، ومهارات حلّ المشكلات، وبإجمالي (23) عبارة للمقياس كاملاً، وذلك بالاستعانة بالأدب التربوي والدراسات السابقة ذات الصلة بموضوع الدراسة. تأكّد الباحثون من صدق المقياس وثباته. أظهرت نتائج الدراسة فاعلية تطبيق منصة جوجل كلاس روم (Google Classroom) في اكتساب الطلبة مهارات التعلّم الذاتي وحلّ المشكلات، وفقًا لتصوّرات معلمي العلوم، وبمتوسط حسابي مرتفع للمقياس ككل. أوصت الدراسة بضرورة دمج التعلّم الإلكتروني في التعليم؛ لتعزيز العمل التعاوني والجماعي، وتوظيف منصة جوجل كلاس روم (Google Classroom) في تعليم العلوم، والمقررات الدراسية الأخرى.Abstract: The current study's main aim was to monitor science teachers' perceptions for grades five to eight about the effectiveness of the Google Classroom application in equipping students with self-learning and problem-solving skills. The sample of this study consisted of (104) male-teacher and (293) female teachers from eight educational governorates in the Sultanate of Oman. To achieve the objectives of this study, the study used the descriptive methodology by developing a questionnaire. This questionnaire was established based on educational literature and previous studies. It was divided into two domains: self-learning and problem-solving skills, including (23) items. The reliability and the validity of the questionnaire were verified. The result revealed the effectiveness of the Google classroom platform in equipping students with self-learning and problem-solving skills according to the science teachers' perceptions with a high arithmetic average for the questionnaire. The study recommended the necessity of integrating e-learning into education to enhance collaborative and collective work and employing the Google classroom platform application in science education and other academic courses.&nbsp

Eosinophilic Pneumonia in a Patient with Bronchial Myiasis : Case report and literature review

Pulmonary myiasis is an unusual form of myiasis in humans and has been recently identified as a cause of eosinophilic pneumonia. We report the case of a 13-year-old Omani boy who presented to the Royal Hospital, Muscat, Oman, in October 2014 with respiratory distress. Bronchial aspirates revealed features of eosinophilic pneumonia. Possible larvae identified in the cytology report, a high immunoglobulin E level and the patient history all indicated bronchial myiasis. The patient was treated with steroids and ventilation and has since been diseasefree with no long-term side-effects. To the best of the authors’ knowledge, this is the first case of bronchial myiasis in Oman