213 research outputs found
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A study of the effects of interactive writing on reading comprehension in fifth grade.
This study describes an experimental fifth grade reading class in which an interactive writing program replaced the traditional school model\u27s follow-up activities of workbooks, skill worksheets or assigned comprehension questions. For the purpose of the case-study, the researcher made careful, systematic observations, collected samples of the students\u27 work and kept detailed ethnographic notes for an entire year. The researcher hoped to learn about the complementary relationship between reading and writing and more specifically the effects of a writing-infused program on the reading comprehension ability of the students involved. The subjects of the study were a group of fourteen students selected from the middle of a class of sixty-one fifth graders. The median IQ for the entire fifth grade was 108, while it was 100 for the fourteen students participating in the study group. The IQ ranged from 93-117. In this dissertation can be found the results of the writer\u27s exploration and her answers to five research questions. Did the students make observable improvements in their writing abilities and skills? Did the writing-infused students make gains in reading comprehension? How did the writing-infused students perform in tests measuring traditional language and reading achievement as compared to the other fifth grade students in the same school receiving traditional reading instruction as recommended by the teacher\u27s manual for their basal reader? How useful did the writing-infused students feel the writing activities were to their reading and writing development? And lastly, how much interest and enjoyment did the students have in the interactive writing activities? The findings cited in this study support the researcher\u27s belief that students can be taught a process of writing that will positively affect their general reading ability--specifically their reading comprehension. The performance of the reading-writing students compared favorably to the performance of the students in the traditional classrooms. The students found the writing instruction to be appealing, informative and instructive and as a result made great progress in their competencies
The application of compound-specific sulfur isotopes to the oilâsource rock correlation of Kurdistan petroleum
The concentrations and δ34S values of thioaromatic compounds of a suite of oils from several major oil fields in Kurdistan and their corresponding regional Type II-S source rocks have been measured to investigate their source relationship. The oils of three fields (Khabbaz, Jambur, Ajeel) and the bitumen extracted from specific rock formations (Alan, Sargelu, Naokelekan, Chia Gara) showed particularly high abundances of thioaromatics consistent with a carbonate source deposited in a restricted sulfate-rich marine platform setting. The δ34S [V-CDT] values of the major organosulfur compounds (OSCs) in these petroleum samples were measured with a gas chromatograph coupled to a multi-collector inductively coupled plasma mass spectrometer. δ34S values of dibenzothiophenes and methyldibenzothiophenes were consistently in the range â4â° to â12â° and â9â° to â18â° for the oils and rocks, respectively. Separate groupings of oils and rocks were distinguishable by >âŻ2â° difference, given an analytical reproducibility of <âŻ0.8â°. OSCs from rocks were consistently âź2â4â° depleted than in oils, reflecting a similar trend to previous bulk δ34S studies from which an initial evolution of 34S depleted H2S during diagenesis and thermal maturation had been proposed. Distinctive δ34SOSC data of the oils and rocks with particularly high thioaromatic abundances did suggest several oilsâsource rock relationships: the Ajeel and Jambur oils and sediments from the Chia Gara formation yielded relatively enriched δ34SOSC values, whereas consistently depleted δ34SOSC values were observed for the Khabbaz oil and Naokelekan source rocks. Results suggest that compound-specific S isotope analysis can help establish oilâsource rock relationships of S-rich petroleum
An open ocean record of the Toarcian oceanic anoxic event
Oceanic anoxic events were time intervals in the Mesozoic characterized by widespread distribution of marine organic matter-rich sediments (black shales) and significant perturbations in the global carbon cycle. These perturbations are globally recorded in sediments as carbon isotope excursions irrespective of lithology and depositional environment. During the early Toarcian, black shales were deposited on the epi- and pericontinental shelves of Pangaea, and these sedimentary rocks are associated with a pronounced (ca. 7 â°) negative (organic) carbon isotope excursion (CIE) which is thought to be the result of a major perturbation in the global carbon cycle. For this reason, the lower Toarcian is thought to represent an oceanic anoxic event (the T-OAE). If the T-OAE was indeed a global event, an isotopic expression of this event should be found beyond the epi- and pericontinental Pangaean localities. To address this issue, the carbon isotope composition of organic matter (δ13Corg of lower Toarcian organic matter-rich cherts from Japan, deposited in the open Panthalassa Ocean, was analysed. The results show the presence of a major (>6 â°) negative excursion in δ13Corg that, based on radiolarian biostratigraphy, is a correlative of the lower Toarcian negative CIE known from Pangaean epi- and pericontinental strata. A smaller negative excursion in δ13Corg (ca. 2 â°) is recognized lower in the studied succession. This excursion may, within the current biostratigraphic resolution, represent the excursion recorded in European epicontinental successions close to the Pliensbachian/Toarcian boundary. These results from the open ocean realm suggest, in conjunction with other previously published datasets, that these Early Jurassic carbon cycle perturbations affected the active global reservoirs of the exchangeable carbon cycle (deep marine, shallow marine, atmospheric)
Palaeoceanography: Methane release in the Early Jurassic period (Reply)
Wignall et al. suggest that the abrupt negative delta13Corg shifts that we recognize in our data set could be localized features caused by recycling of isotopically light marine carbon. This overlooks two important lines of evidence: that the early Toarcian negative delta13C excursion is present in several sections around the world and that the excursion is recorded in terrestrial plant material. These crucial observations together preclude the possibility that the event was restricted to a localized, marine environment
Radiolytic alteration of biopolymers in the Mulga Rock (Australia) uranium deposit
We investigated the effect of ionizing radiation on organic matter (OM) in the carbonaceous uranium (U) mineralization at the Mulga Rock deposit, Western Australia. Samples were collected from mineralized layers between 53 and 58.5 m depths in the Ambassador prospect, containing <5300 ppm U. Uranium bears a close spatial relationship with OM, mostly finely interspersed in the attrinite matrix and via enrichments within liptinitic phytoclasts (mainly sporinite and liptodetrinite). Geochemical analyses were conducted to: (i) identify the natural sources of molecular markers, (ii) recognize relationships between molecular markers and U concentrations and (iii) detect radiolysis effects on molecular marker distributions. Carbon to nitrogen ratios between 82 and 153, and RockâEval pyrolysis yields of 316â577 mg hydrocarbon/g TOC (HI) and 70â102 mg CO2/g TOC (OI) indicate a predominantly lipid-rich terrigenous plant OM source deposited in a complex shallow swampy wetland or lacustrine environment. Saturated hydrocarbon and ketone fractions reveal molecular distributions co-varying with U concentration. In samples with <1700 ppm U concentrations, long-chain n-alkanes and alkanones (C27âC31) reveal an odd/even carbon preference indicative of extant lipids.Samples with ⊞1700 ppm concentrations contain intermediate-length n-alkanes and alkanones, bearing a keto-group in position 2â10, with no carbon number preference. Such changes in molecular distributions are inconsistent with diagenetic degradation of terrigenous OM in oxic depositional environments and cannot be associated with thermal breakdown due to the relatively low thermal maturity of the deposits (Rr = 0.26%). It is assumed that the intimate spatial association of high U concentrations resulted in breakdown via radiolytic cracking of recalcitrant polyaliphatic macromolecules (spores, pollen, cuticles, or algal cysts) yielding medium chain length n-alkanes (C13âC24). Reactions of n-alkenes with OHâ radicals from water hydrolysis produced alcohols that dehydrogenated to alkanones or through carbonylation formed alkanones. Rapid reactions with hydroxyl radicals likely decreased the isomerization of n-alkenes and decreased alkanone diversity, such that the alkan-2-one isomer is predominant. This specific distribution of components generated by natural radiolysis enables their application as âradiolytic molecular markersâ. Breaking of CâC bonds through radiolytic cracking at temperatures much lower than the oil window (<50 °C) can have profound implications on initiation of petroleum formation, paleoenvironmental reconstructions, mineral exploration and in tracking radiolysis of OM
Exceptional preservation of palaeozoic steroids in a diagenetic continuum
The occurrence of intact sterols has been restricted to immature Cretaceous (~125 Ma) sediments with one report from the Late Jurassic (~165 Ma). Here we report the oldest occurrence of intact sterols in a Crustacean fossil preserved for ca. 380 Ma within a Devonian concretion. The exceptional preservation of the biomass is attributed to microbially induced carbonate encapsulation, preventing full decomposition and transformation thus extending sterol occurrences in the geosphere by 250 Ma. A suite of diagenetic transformation products of sterols was also identified in the concretion, demonstrating the remarkable coexistence of biomolecules and geomolecules in the same sample. Most importantly the original biolipids were found to be the most abundant steroids in the sample. We attribute the coexistence of steroids in a diagenetic continuum-ranging from stenols to triaromatic steroids-to microbially mediated eogenetic processes
Serum Cannabinoid 24 h and 1 Week Steady State Pharmacokinetic Assessment in Cats Using a CBD/CBDA Rich Hemp Paste
Hemp based cannabinoids have gained popularity in veterinary medicine due to the potential to treat pain, seizure disorders and dermatological maladies in dogs. Cat owners are also using hemp-based products for arthritis, anxiety and neoplastic disorders with no studies assessing hemp cannabinoids, namely cannabidiol efficacy, for such disorders. Initial twenty-four pharmacokinetic and chronic dosing serum concentration in cats are sparse. The aim of our study was to assess 8 cats physiological and 24 h and 1-week steady state pharmacokinetic response to a cannabidiol (CBD) and cannabidiolic acid (CBDA) rich hemp in a palatable oral paste. Using a standard dose of paste (6.4 mg/CBD + CBDA 5.3 mg/gram) across 8 cats weighing between 4.2 and 5.4 kg showed an average maximal concentration of CBD at 282.0 Âą 149.4 ng/mL with a half-life of ~2.1 Âą 1.1 h, and CBDA concentrations of 1,011.3 Âą 495.4 ng/mL with a half-life of ~2.7 Âą 1.4 h, showing superior absorption of CBDA. After twice daily dosing for 1 week the serum concentrations 6 h after a morning dosing showed that the acidic forms of the cannabinoids were approximately double the concentration of the non-acidic forms like CBD and Î9- tetrahydrocannabinol (THC). The results of this study compared to two other recent studies suggest that the absorption in this specific paste product may be superior to oil bases used previously, and show that the acidic forms of cannabinoids appear to be absorbed better than the non-acidic forms. More importantly, physical and behavioral examinations every morning after dosing showed no adverse events related to neurological function or behavioral alterations. In addition, bloodwork after 1 week of treatment showed no clinically significant serum biochemical alterations as a reflection of hepatic and renal function all remaining within the reference ranges set by the diagnostic laboratory suggesting that short-term treatment was safe
Physiological and pathophysiological homeostasis of astroglial channel proteins by Nedd4-2
Nedd4-2 is an E3 ubiquitin ligase, missense mutation of which is related to familial epilepsy, indicating its critical role in regulating neuronal network activity. However, Nedd4-2 substrates involved in neuronal network function have yet to be identified. Using mouse lines lacking Nedd4-1 and Nedd4-2, we identified astrocytic channel proteins inwardly rectifying K+ channel 4.1 (Kir4.1) and Connexin43 as Nedd4-2 substrates. We found that the expression of Kir4.1 and Connexin43 is increased upon conditional deletion of Nedd4-2 in astrocytes, leading to an elevation of astrocytic membrane ion permeability and gap junction activity, with a consequent reduction of Îł-oscillatory neuronal network activity. Interestingly, our biochemical data demonstrate that missense mutations found in familial epileptic patients produce gain-of-function of Nedd4-2 gene product. Our data reveal a process of coordinated astrocytic ion channel proteostasis that controls astrocyte function and astrocyte-dependent neuronal network activity, and elucidate a potential mechanism by which aberrant Nedd4-2 function leads to epilepsy
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