34 research outputs found
Readability index of essays as an alternative to the scoring procedure in L2 academic writing
Samples of participants’ writing were scored by two raters using TOEFL writing scoring rubric. The readability index of each text was calculated through the use of six readability formulae and graphs, i.e., Flesch-Kincaid index, Reading Ease index, FOG index, SMOG formula, Fry’s graph, and Dale-Chall readability index. The scores given to each essay were later compared to the obtained readability indices through the use of Spearman rho correlation coefficient formula. The correlation coefficients obtained ranged from .05 to .15, none of which significant. This indicates that readability index of a text and the writing assessment procedure through holistic rubrics are dealing with two different constructs and have very little in common. This also calls into question the reliability and validity of some computerized assessment programs such as PEG, LSA, or E-rater, which take into account factors very similar to those examined in readability formulae.
Motivating the Unmotivated: Making Teacher Corrective Feedback Work
It is often wrongly assumed that the provision of teacher corrective feedback naturally entails learners' attendance to and application of it, but learners have repeatedly been reported not to pay attention to teacher feedback due to lack of motivation and the distracting effect of the grades they receive. The present study was an attempt to tackle this problem. To do so, the technique named Draft-Specific Scoring (Nemati & Azizi, 2013) was implemented. In DSS, learners receive both teacher feedback and grades on their first drafts; however, they are given up to two opportunities to apply teacher feedback and revise their drafts accordingly. The scores they receive may improve as a result of the quality of revisions they make. Students’ final scores will be the mean score of the grades they receive on the final drafts of each assignment. 57 Iranian intermediate students attending the ‘Advanced Writing’ course at University of Teheran, with an age range of 21 to 27 took part in this study. The gain score analysis and the SPANOVA used showed the superiority of DSS over more traditional methods in improving learners’ overall writing proficiency as well as fluency and accuracy of their written texts. Moreover, no adverse effect was observed for the treatment group regarding the grammatical complexity of their texts. This indicates that in order to make teacher feedback work, there are a number of intervening variables one needs to consider, the most important of which being learners’ motivation to attend to teacher feedback
ISPIRANJE ŽELJEZA IZ SIROMAŠNE RUDE BOKSITA U CILJU NJEZINE UPORABE U VATROSTALNOJ INDUSTRIJI
Iron-bearing minerals are the most important interfering compounds that are found with bauxite reserves. The element iron has adverse effects on bauxite applications, including the use of bauxite in refractory soils. The purpose of this research is to investigate the possibility of iron removal from low-grade bauxite ores to utilize them in refractory industries. For achieving this purpose, iron removal tests were performed on bauxite samples with an alumina to silica modulus of 0.73. After determining the appropriate iron removal method among the magnetic separation, calcination, and leaching (with H2SO4 and HCl) processes, optimal separation conditions were determined by tests that were designed using the Taguchi method. According to leaching results, using HCl for raw feed (un-calcined) provided the best result for iron removal. During this test, Fe2O3 grade decreased from 5.14% to 0.08%, and the alumina to silica modulus increased to 0.75. Calcination of the concentrate obtained from this test has led to favorable results in reducing the Fe2O3 grade (0.04%) and increasing the Al2O3 grade. Afterwards, in tests designed by the Taguchi method, the effect of parameters such as time, process temperature, HCl concentration, and feed grain size on iron removal from bauxite by HCl leaching processes are discussed. According to the results, the best efficiency of iron removal for a feed grain size of 250 µm is achieved in the following conditions: 30% HCl, process temperature of 25°C, and process time of 120 minutes. In this case, iron removal efficiency and Fe2O3 grade in process concentrate are 92.78% and 0.56%, respectively.Minerali nosioci željeza najvažnije su nečistoće koje se nalaze u rezervama boksita. Željezo ima štetne učinke na primjenu boksita, uključujući korištenje boksita u vatrostalnim tlima. Svrha je ovoga rada istražiti mogućnost uklanjanja željeza iz ruda boksita niske kvalitete radi iskorištavanja u vatrostalnoj industriji. U tu svrhu provedena su ispitivanja izdvajanja željeza na uzorcima boksita s modulom aluminijeva oksida i silicija od 0,73. Nakon utvrđivanja odgovarajuće metode za izdvajanje željeza, uključujući magnetsku separaciju, kalcinaciju i luženje (s H2SO4 i HCl), određeni su optimalni uvjeti izdvajanja uz upotrebu Taguchijeve metode. Rezultati luženja HCl-om rovne sirovine (nekalcinirane) dali su najbolji rezultat izdvajanja željeza. Tijekom ovoga ispitivanja udio Fe2O3 smanjio se s 5,14 % na 0,08 %, a modul aluminijeva oksida i silicija povećao se na 0,75. Kalciniranje koncentrata dobivenoga ovim ispitivanjem dovelo je do povoljnih rezultata u smanjenju nekorisne komponente Fe2O3 (0,04 %) i povećanju korisne komponente Al2O3 . Nakon toga u ispitivanjima dizajniranim Taguchijevom metodom određen je utjecaj parametara kao što su vrijeme, temperatura procesa, koncentracija HCl i veličina zrna sirovine, na uklanjanje željeza iz boksita procesima luženja HCl. Prema dobivenim rezultatima najbolja učinkovitost uklanjanja željeza za veličinu ulaznoga zrna od 250 µm postiže se u sljedećim uvjetima: 30 % HCl, temperatura procesa od 25°C i vrijeme procesa 120 minuta. U ovome slučaju učinkovitost uklanjanja željeza i sadržaj Fe2O3 u procesnome koncentratu iznosi 92,78 % odnosno 0,56 %
Simultaneous Determination of TetracyclinesResidues in Bovine Milk Samples by Solid Phase Extraction and HPLC-FL Method
Introduction:Tetracyclines (TCs) are widely used in animal husbandry and their residues in milk may resultinharmful effects on human. The aim of this study was to investigate the presence of TCs residues in various bovine milk samples from local markets of Ardabil, Iran. Methods:One hundred and fourteen pasteurized, sterilized and raw milk samples were collected from markets of Ardabil. Tetracycline, Oxytetracycline and Chlortetracycline (TCs) residues extraction carried out by Solid Phase Extraction method. Determination of TCs residues were performed by high performance liquid chromatography (HPLC) method using Fluorescence detector.Results: The mean of total TCs residues in all samples (114 samples) was 97.6 ±16.9ng/g and that of pasteurized, sterilized and raw milk samples were 87.1 ± 17.7, 112.0 ± 57.3 and 154.0 ± 66.3ng/g respectively. Twenty five point four percent of the all samples, and24.4%, 30% and 28.6% of the pasteurized, sterilized and raw milk samples, respectively had higher TCs residues than the recommended maximum levels (100ng/g). Conclusion:This study indicates the presence of tetracycline residues more than allowed amount. Regulatory authorities should ensure proper withdrawal period before milking the animals and definite supervisions are necessary on application of these drugs
2,6-Diaminopyridinium bis(4-hydroxypyridine-2,6-dicarboxylato-κ3 O 2,N,O 6)ferrate(III) dihydrate
The reaction of iron(II) sulfate heptahydrate with the proton-transfer compound (pydaH)(hypydcH) (pyda = pyridine-2,6-diamine; hypydcH2 = 4-hydroxypyridine-2,6-dicarboxylic acid) in an aqueous solution led to the formation of the title compound, (C5H8N3)[Fe(C7H3NO5)2]·2H2O. The anion is a six-coordinated complex with a distorted octahedral geometry around the FeIII atom. Extensive intermolecular O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, involving the complex anion, (pydaH)+ counter-ion and two uncoordinated water molecules, and π–π [centroid-to-centroid distance 3.323 (11) Å] and C—O⋯π [O–centroid distance 3.150 (15) Å] interactions connect the various components into a supramolecular structure
Hemipiperazinediium bis(pyridine-2,6-dicarboxylato-κ3 O,N,O′)gallate(III) pyridine-2,6-dicarboxylic acid dihydrate
The asymmetric unit of the title compound, (C4H12N2)0.5[Ga(pydc)2]·pydcH2·2H2O, where pydcH2 is pyridine-2,6-dicarboxylic acid, C7H5NO4, contains one half of a centrosymmetric piperazinediium dication, one anion, one uncoordinated pydcH2 molecule and two uncoordinated water molecules, one of which is disordered over two sites in a 1:1 ratio. In the anion, the GaIII ion is coordinated by four O atoms [Ga—O = 1.9706 (16)–2.0494 (15) Å] and two N atoms [Ga—N = 1.9660 (18) and 1.9709 (17) Å] from two pydc ligands in a distorted octahedral geometry. The crystal structure exhibits intermolecular O—H⋯O, N—H⋯O and O—H⋯N hydrogen bonds and π–π interactions [centroid–centroid distances of 3.5359 (13) and 3.6550 (14) Å]
Ultrasonographic Evaluation of Bowel Wall Thickness and Intramural Blood Flow in Ulcerative Colitis
Aim. This study aimed at assessing Doppler ultrasonographic findings of gut wall vessels and thickness in active and quiescent ulcerative colitis. Methods. Fifty patients with ulcerative colitis were studied using transabdominal grayscale and Doppler sonography of sigmoid, distal and middle parts of descending colon in different stages of the disease. Thickness of colon wall in the most involved site, number of color signals in each box, resistive index (RI), and pulsatility index (PI) were evaluated.
Results. The median thickness of the colon wall in the most involved sites was 4.3 mm in acute phase and 4.4 mm in the inactive phase (P = 0.47). The median number of the color signals in the active phase at the most involved site, distal part of descending colon and sigmoid was higher than that of the color signals in the inactive phase (P = 0.0001). In the most involved site, the PI and RI were undetectable in the inactive phase. The median PI was 1.4 in the mild phase, 1.3 in the moderate phase, and 1.1 in the severe phase (P = 0.002). Conclusion. In contrast to the colon wall thickness, increased intramural blood flow reflected the clinical severity in ulcerative colitis patients
Comparison of normal values of Duplex indices of vertebral arteries in young and elderly adults
<p>Abstract</p> <p>Background</p> <p>Considering the role of aging in brain atrophy and cerebral vascular demand, we carried out this study to clarify the role of aging in duplex indices of vertebral arteries.</p> <p>Methods</p> <p>From June 2005 to June 2006, 96 volunteers with age range of 20 to 95 years, were evaluated with color doppler for duplex indices of vertebral arteries. Sever hemodynamic stenosis was excluded in all of these patients. These volunteers were subdivided in two groups: younger and older than 60 year old. In all of these patients we measured diameter, peak systolic velocity (PSV), resistive index (RI), and flow volume (FV) of vertebral arteries in right and left sides.</p> <p>Results</p> <p>There was no significant difference in diameter, PSV, RI and FV between two groups. We have clarified that in patients younger than 60 year old, comparing right and left vertebral arteries, PSV and FV were higher in left side.</p> <p>Conclusion</p> <p>Duplex indices of vertebral arteries are age independent in adults.</p
Sex differences in cerebral venous sinus thrombosis after adenoviral vaccination against COVID-19
Introduction: Cerebral venous sinus thrombosis associated with vaccine-induced immune thrombotic thrombocytopenia (CVST-VITT) is a severe disease with high mortality. There are few data on sex differences in CVST-VITT. The aim of our study was to investigate the differences in presentation, treatment, clinical course, complications, and outcome of CVST-VITT between women and men. Patients and methods: We used data from an ongoing international registry on CVST-VITT. VITT was diagnosed according to the Pavord criteria. We compared the characteristics of CVST-VITT in women and men. Results: Of 133 patients with possible, probable, or definite CVST-VITT, 102 (77%) were women. Women were slightly younger [median age 42 (IQR 28–54) vs 45 (28–56)], presented more often with coma (26% vs 10%) and had a lower platelet count at presentation [median (IQR) 50x109/L (28–79) vs 68 (30–125)] than men. The nadir platelet count was lower in women [median (IQR) 34 (19–62) vs 53 (20–92)]. More women received endovascular treatment than men (15% vs 6%). Rates of treatment with intravenous immunoglobulins were similar (63% vs 66%), as were new venous thromboembolic events (14% vs 14%) and major bleeding complications (30% vs 20%). Rates of good functional outcome (modified Rankin Scale 0-2, 42% vs 45%) and in-hospital death (39% vs 41%) did not differ. Discussion and conclusions: Three quarters of CVST-VITT patients in this study were women. Women were more severely affected at presentation, but clinical course and outcome did not differ between women and men. VITT-specific treatments were overall similar, but more women received endovascular treatment.</p