The Constructs of PhD Students about Infinity: An Application of Repertory Grids

Infinity has been one of the more difficult concepts for humanity to grasp. A major component of the research on mathematics education related to infinity has been the study of student’s conceptions and reasoning about calculus subjects, particularly limits and series. Some related studies are about Cantor’s ordinal and cardinal infinity. However since most students at the high school and college level are unfamiliar with symbolic representations and terminology, such as a set theoretic approach, a context (generally geometric) is used for investigating notions of infinity indirectly. In this paper we report on a study on the constructs of PhD Students about the notion of infinity. The aim of our study was to gain insight into the constructs about infinity held by PhD students and to investigate the effects of a graduate level set theory course on their informal models. We also propose repertory grid methodology as a way of capturing the constructs of students and argue that this methodology can help us to learn further details about the understanding of infinity

Comperative Analysis of Problem Posing Ability Between the Anatolian High School Students and the Public High School Students Located in Bagcilar District of Istanbul

AbstractThe purpose of this case study was to investigate the problem posing abilities of the “Anatolian High School” students and the “Public High School” students who had been studying in the Bagcilar district of the city of Istanbul.The methodology employed in the study was qualitative in nature. Document analysis method was applied. The participants, who had been successful for an exam carried out by a private course located in the district of Bagcilar of Istanbul, were including four “Anatolian High School” 11 th grade students and the other four “Public High School” 11 th grade students. In the research, students were provided with five different types of worksheets for problem posing Types of worksheets were including story editing, information translating, problem posing according to the previously defined equation, figure and result or conclusion. As a result of the study, two “Public High School” students could not accomplish the study concerning the problem posing according to the previously defined equation. On the other hand, the “Anatolian High School” students were much more successful than the “Public High School” students

Fibrin sealant as a carrier for sustained delivery of antibiotics

Objective: To evaluate the activity and sustained release of antibiotics from fibrin sealant against common strains of ocular bacteria. Methods: Vancomycin, ceftazidime, moxifloxacin and lomefloxacin were incorporated into fibrin sealant in the shape of discs. Each antibiotic disc and control fibrin disc without drug was tested in vitro against standard bacterial strains of Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae and Pseudomonas aeroginosa. After 24 hours of incubation at 37 °C, the discs were transferred to new plates of bacteria and triplicated for each antibiotic. Results: All antibiotic discs demonstrated detectable activity after 24 hours. Vancomycin had the longest duration of activity (4 days) on the S. pneumonia grown plate. The moxifloxacin discs showed a prolonged inhibition of S. aureus and S. pneumonia for 3 days and inhibited the other strains for 2 days. Conclusion: Fibrin sealants provided prolonged drug delivery, which indicates that antibiotic-loaded fibrin clots could be useful for early ocular postoperative care and treatment. J Clin Exp Invest 2014; 5 (2): 194-19

Efficient computation of the Ambiguity Function and the Wigner Distribution on arbitrary line segments

Efficient algorithms are proposed for the computation of Wigner distribution and ambiguity function samples on arbitrary line segments based on the relationship of Wigner distribution and ambiguity function with the fractional Fourier transformation. The proposed algorithms make use of an efficient computation algorithm of fractional Fourier transformation to compute N uniformly spaced samples O(N log N) flops. The ability of obtaining samples on arbitrary line segments provides significant freedom in the shape of the grids used in the Wigner distribution or in ambiguity function computations

Theoretical investigation on exact blind channel and input sequence estimation

Recent work on fractionally spaced blind equalizers have shown that it is possible to exactly identify the channel and its input sequence from the noise-free channel outputs. However, the obtained results are based on a set of over-restrictive constrainst on the channel. In this paper it is shown that the exact identification can be achieved in a broader class of channels

Robust Transmission of Multi-View Video Streams Using Flexible Macroblock Ordering and Systematic LT codes

The transmission of fully compatible H.264/AVC multi-view video coded streams over packet erasure networks is examined. Macroblock classification into unequally important slice groups is considered using the flexible macroblock ordering (FMO) tool of H.264/AVC. Systematic LT codes are used for error protection due to their low complexity and advanced performance. The optimal slice grouping and channel rate allocation are jointly determined by an iterative optimization algorithm based on dynamic programming. The experimental evaluation clearly demonstrates the validity of the proposed method

Clinical Study The Role of Serum Cytokines in the Pathogenesis of Hepatic Osteodystrophy in Male Cirrhotic Patients

Objective. In this study, we aimed to investigate the possible role of serum cytokines in the development of hepatic osteodystrophy. Matherial and Methods. 44 consecutive male cirrhotic patients (17 alcoholic, 20 hepatitis B, 7 hepatitis C), 15 age-and sex-matched chronic alcoholics without liver disease, and 17 age-and sex-matched healthy controls were included in the study during one year period. Bone mineral density was measured by dual X-ray absorptiometry in the lumbar vertebrate and femoral neck. Serum interleukin levels were measured by ELISA method. Results. Although osteopenia frequency between our cirrhotic patients was 20%, there was no difference in T-scores among the controls and other groups. Serum interleukin-1, interleukin-8, and tumor necrosis factor-alpha levels were not different between all groups. Serum interleukin-2 and interleukin-6 levels were higher in the cirrhotics than controls (P < 0.001). However, there were no significant difference between osteopenic and nonosteopenic cirrhotics. Conclusion. According to the results of the study in this small population of 44 male cirrhotic patients, frequency of hepatic osteopenia is small and serum interleukins 1, 2, 6, 8, and tumor necrosis factor-alpha may not play a role in the pathogenesis of hepatic osteodystrophy. Further studies in which large number of patients involved are necessary in this field

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat