456 research outputs found
THE EFFECT OF REFLECTIVE PRACTICE ON HIGH SCHOOL SCIENCE STUDENTS’ CRITICAL AND REFLECTIVE THINKING
This study investigates the impact of a reflection treatment program on the critical thinking skills and reflection level of high school science students. Although research indicates there is a connection between reflection and critical thinking, there is limited empirical research related to this topic in high school science classrooms. Therefore, this study will attempt to determine whether a reflection implementation not only improves selected domains of critical thinking, but also impacts the level of reflective thinking in high school science students.
The research took place in a small, suburban high school in the northeast from January to May of the year 2013. A sample of convenience comprised of high school students, 9th through 12th grade was used. The study was quasi-experimental in nature, with a pretest/posttest comparison group design using intact classrooms of students. Administration of two instruments measuring the characteristics of dispositions associated with critical thinking and the level of reflective thinking were used. The scores of those students who received the reflection treatment were compared to the scores of those students in the traditional science classroom who did not receive the treatment to determine the impact of this method of delivering instruction. In the multivariate analysis of variance, data revealed that there was a statistically significant difference, (p = .020) between the means of the treatment and comparison groups as measured by the Reflective Thinking Questionnaire (RTQ). The reflective practice treatment group scored significantly higher for the sub-scale of Reflection (p = .007) than the comparison group. In the hierarchal multiple regression analysis, the variable of Reflection, as measured by the RTQ, significantly predicted mean scores of Mental Focus (p = .022) and Cognitive Integrity (p = .048) as measured by the California Measure of Mental Motivation (CM3). Findings suggest that students who engage in reflective practice in science class will have significantly higher levels of reflection, as measured by the RTQ, than students who do not. In addition, students’ levels of reflective thinking predict their critical thinking dispositions of Mental Focus and Cognitive Integrity
OpenFluor- an online spectral library of auto-fluorescence by organic compounds in the environment
An online repository of published organic fluorescence spectra has been developed, which can be searched for quantitative matches with any set of unknown spectra. It fills a critical gap by increasing access to measured and modelled (PARAFAC) spectra, and linking across studies and systems to reveal "global" fluorescence trends
Fluorescence quantum yields of natural organic matter and organic compounds: Implications for the fluorescence-based interpretation of organic matter composition
Absorbance and fluorescence spectroscopy are economical tools for tracing the supply, turnover and fate of dissolved organic matter (DOM). The colored and fluorescent fractions of DOM (CDOM and FDOM, respectively) are linked by the apparent fluorescence quantum yield (AQY) of DOM, which reflects the likelihood that chromophores emit fluorescence after absorbing light. Compared to the number of studies investigating CDOM and FDOM, few studies have systematically investigated AQY spectra for DOM, and linked them to fluorescence quantum yields (Ф) of organic compounds. To offer a standardized approach, a MATLAB toolbox for the determination of apparent quantum yields of DOM (aquaDOM), featuring two calculation approaches, was developed and used to derive AQYs for samples from the Norwegian Sea. Ф of the organic compounds varied between 0.00079 and 0.35, whereas the average AQY for DOM samples at 350 nm was 0.011 ± 0.003. The AQY at 350 nm increased with depth, while the AQY at 250 nm showed no trend. Laboratory tests indicated that Ф of compound mixtures are additive and represent an intermediate of the constituents. Additionally, the presence of non-fluorescent chromophores greatly suppressed calculated AQYs. Similar trends in the DOM AQY at 350 nm were observed in natural samples. We therefore hypothesize that fluorescence AQYs can indicate changes in the relative abundances of CDOM and FDOM. Additionally, the optical properties of 15 potential DOM constituents were determined and compared to more than 200 modelled spectra (PARAFAC components) in the OpenFluor database. Apparent matches, based on spectral similarity, were subsequently evaluated using molar fluorescence and absorbance. Five organic compounds were potential matches with PARAFAC components from 16 studies; however, the ability to confirm matches was limited due to multiple compounds exhibiting very similar spectra. This reiterates the fact that spectral similarity alone is insufficient evidence of the presence of particular compounds, and additional evidence is required
The one-sample PARAFAC approach reveals molecular size distributions of fluorescent components in dissolved organic matter
Molecular size plays an important role in dissolved organic matter (DOM) biogeochemistry, but its relationship with the fluorescent fraction of DOM (FDOM) remains poorly resolved. Here high-performance size exclusion chromatography (HPSEC) was coupled to fluorescence emission-excitation (EEM) spectroscopy in full spectral (60 emission and 34 excitation wavelengths) and chromatographic resolution (<1 Hz), to enable the mathematical decomposition of fluorescence on an individual sample basis by parallel factor analysis (PARAFAC). The approach allowed cross-system comparisons of molecular size distributions for individual fluorescence components obtained from independent data sets. Spectra extracted from allochthonous DOM were highly similar. Allochthonous and autochthonous DOM shared some spectra, but included unique components. In agreement with the supramolecular assembly hypothesis, molecular size distributions of the fluorescence fractions were broad and chromatographically unresolved, possibly representing reoccurring fluorophores forming noncovalently bound assemblies of varying molecular size. Samples shared underlying fluorescence components that differed in their size distributions but not their spectral properties. Thus, in contrast to absorption measurements, bulk fluorescence is unlikely to reliably indicate the average molecular size of DOM. The one-sample approach enables robust and independent cross-site comparisons without large-scale sampling efforts and introduces new analytical opportunities for elucidating the origins and biogeochemical properties of FDOM
Fluorescence spectroscopy and multi-way techniques. PARAFAC
PARAllel FACtor analysis (PARAFAC) is increasingly used to decompose fluorescence excitation emission matrices (EEMs) into their underlying chemical components. In the ideal case where fluorescence conforms to Beers Law, this process can lead to the mathematical identification and quantification of independently varying fluorophores. However, many practical and analytical hurdles stand between EEM datasets and their chemical interpretation. This article provides a tutorial in the practical application of PARAFAC to fluorescence datasets, demonstrated using a dissolved organic matter (DOM) fluorescence dataset. A new toolbox for MATLAB is presented to support improved visualisation and sensitivity analyses of PARAFAC models in fluorescence spectroscopy. © 2013 The Royal Society of Chemistry
Assessment of drinking water quality at the tap using fluorescence spectroscopy
Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap relative to the water leaving the treatment plant is a potential indicator of contamination, and can be measured sensitively, inexpensively and potentially on-line via fluorescence and absorbance spectroscopy. Detecting elevated DOM requires potential contamination events to be distinguished from natural fluctuations in the system, but how much natural variation to expect in a stable distribution system is unknown. In this study, relationships between DOM optical properties, microbial indicator organisms and trace elements were investigated for households connected to a biologically-stable drinking water distribution system. Across the network, humic-like fluorescence intensities showed limited variation (RSDÂ =Â 3.5-4.4%), with half of measured variation explained by interactions with copper. After accounting for quenching by copper, fluorescence provided a very stable background signal (RSD
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Refining genetic boundaries for Agassiz’s desert tortoise (Gopherus agassizii) in the western Sonoran Desert: the influence of the Coachella Valley on gene flow among populations in southern California
Understanding the influence of geographic features on the evolutionary history and population structure of a species can assist wildlife managers in delimiting genetic units (GUs) for conservation and management. Landscape features including mountains, low elevation depressions, and even roads can influence connectivity and gene flow among Agassiz’s desert tortoise (Gopherus agassizii) populations. Substantial changes in the landscape of the American Southwest occurred during the last six million years (including the formation of the Gulf of California and the lower Colorado River), which shaped the distribution and genetic structuring of tortoise populations. The area northwest of the Gulf of California is occupied by the Salton Trough, including the Coachella Valley at its northern end. Much of this area is below sea level and unsuitable as tortoise habitat, thus forming a potential barrier for gene flow. We assessed genetic relationships among three tortoise populations separated by the Coachella Valley. Two adjacent populations were on the east side of the valley in the foothills of the Cottonwood and Orocopia mountains separated by Interstate 10. The third population, Mesa, was located about 87 km away in the foothills of the San Bernardino Mountains at the far northwestern tip of the valley. The Cottonwood and Orocopia localities showed genetic affiliation with the adjacent Colorado Desert GU immediately to the east, and the Mesa population exhibited affiliation with both the Southern Mojave and Colorado Desert GUs, despite having a greater geographic distance (0.5x–1.5x greater) to the Colorado Desert GU. The genetic affiliation with the Colorado Desert GU suggests that the boundary for that GU needs to be substantially extended to the west to include the desert tortoise populations around the Coachella Valley. Their inclusion in the Colorado Desert GU may benefit these often overlooked populations when recovery actions are considered
The One-Sample PARAFAC Approach Reveals Molecular Size Distributions of Fluorescent Components in Dissolved Organic Matter
Patient/Family Education for Newly Diagnosed Pediatric Oncology Patients
There is a paucity of data to support evidence-based practices in the provision of patient/family education in the context of a new childhood cancer diagnosis. Since the majority of children with cancer are treated on pediatric oncology clinical trials, lack of effective patient/family education has the potential to negatively affect both patient and clinical trial outcomes. The Children’s Oncology Group Nursing Discipline convened an interprofessional expert panel from within and beyond pediatric oncology to review available and emerging evidence and develop expert consensus recommendations regarding harmonization of patient/family education practices for newly diagnosed pediatric oncology patients across institutions. Five broad principles, with associated recommendations, were identified by the panel, including recognition that (1) in pediatric oncology, patient/family education is family-centered; (2) a diagnosis of childhood cancer is overwhelming and the family needs time to process the diagnosis and develop a plan for managing ongoing life demands before they can successfully learn to care for the child; (3) patient/family education should be an interprofessional endeavor with 3 key areas of focus: (a) diagnosis/treatment, (b) psychosocial coping, and (c) care of the child; (4) patient/family education should occur across the continuum of care; and (5) a supportive environment is necessary to optimize learning. Dissemination and implementation of these recommendations will set the stage for future studies that aim to develop evidence to inform best practices, and ultimately to establish the standard of care for effective patient/family education in pediatric oncology
Infections in hematopoietic cell transplant recipients: Results from the Organ Transplant Infection Project, a multicenter, prospective, cohort study
Background. Infection is a major cause of morbidity and mortality after allogeneic hematopoietic cell transplantation (HCT). Our object was to better define the epidemiology and outcomes of infections after HCT. Methods. This was a prospective, multicenter cohort study of HCT recipients and conducted from 2006 to 2011. The study included 4 US transplant centers and 444 HCT recipients. Data were prospectively collected for up to 30 months after HCT using a standardized data collection tool. Results. The median age was 53 years, and median follow up was 413 (range, 5-980) days. The most common reason for HCT was hematologic malignancy (87%). The overall crude mortality was 52%. Death was due to underlying disease in 44% cases and infection in 21%. Bacteremia occurred in 231 (52%) cases and occurred early posttransplant (median day 48). Gram-negative bloodstream infections were less frequent than Gram-positive, but it was associated with higher mortality (45% vs 13%, P = .02). Clostridium difficile infection developed in 148 patients (33%) at a median of 27 days post-HCT. There were 53 invasive fungal infections (IFIs) among 48 patients (11%). The median time to IFI was 142 days. Of 155 patients with cytomegalovirus (CMV) infection, 4% had CMV organ involvement. Varicella zoster infection (VZV) occurred in 13 (4%) cases and was disseminated in 2. Infection with respiratory viruses was seen in 49 patients. Pneumocystis jirovecii pneumonia was rare (1%), and there were no documented cases of nocardiosis, toxoplasmosis, endemic mycoses, or mycobacterial infection. This study lacked standardized antifungal and antiviral prophylactic strategies. Conclusions. Infection remains a significant cause of morbidity and mortality after HCT. Bacteremias and C difficile infection are frequent, particularly in the early posttransplant period. The rate of IFI is approximately 10%. Organ involvement with CMV is infrequent, as are serious infections with VZV and herpes simplex virus, likely reflecting improved prevention strategies
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