Arithmetic and algebraic problem-solving approaches of prospective teachers and teachers in service

The aim of this study is to determine mathematical problem-solving approaches of elementary school pre-service mathematics teachers and elementary school mathematics teachers. This is a mixed method research and was carried out using exploratory sequential pattern. The sample of the study consists of 128 pre-service teachers (59 sophomores, 41 juniors and 28 seniors) registered to department of elementary mathematics teaching in a state university located in the Eastern Anatolian Region of Turkey and 22 secondary school mathematics teachers working in different cities of Eastern Anatolia Region at the same period. Clinical interviews were conducted with 12 pre-service teacher and 5 teachers. The data were obtained by Problem-solving Test [PST] and Semi-Structured Interview Form [SSIF]. The PST was prepared to examine the problem-solving processes of the teachers and pre-service teachers participating in the research. According to the findings of the research, it was observed that the participants preferred the algebraic approach while solving the problems and could not solve the problem with an arithmetical approach. It is also understood that they tend to use algorithms they know by heart while making algebraic solutions. These results show that the participants have some deficiencies in terms of bringing both arithmetic and algebraic solutions to the problems

Bridging the COVID-19 Data and the Epidemiological Model using Time Varying Parameter SIRD Model

This paper extends the canonical model of epidemiology, SIRD model, to allow for time varying parameters for real-time measurement of the stance of the COVID-19 pandemic. Time variation in model parameters is captured using the generalized autoregressive score modelling structure designed for the typically daily count data related to pandemic. The resulting specification permits a flexible yet parsimonious model structure with a very low computational cost. This is especially crucial at the onset of the pandemic when the data is scarce and the uncertainty is abundant. Full sample results show that countries including US, Brazil and Russia are still not able to contain the pandemic with the US having the worst performance. Furthermore, Iran and South Korea are likely to experience the second wave of the pandemic. A real-time exercise show that the proposed structure delivers timely and precise information on the current stance of the pandemic ahead of the competitors that use rolling window. This, in turn, transforms into accurate short-term predictions of the active cases. We further modify the model to allow for unreported cases. Results suggest that the effects of the presence of these cases on the estimation results diminish towards the end of sample with the increasing number of testing

Generalized Autoregressive Score Trees and Forests

We propose methods to improve the forecasts from generalized autoregressive score (GAS) models (Creal et. al, 2013; Harvey, 2013) by localizing their parameters using decision trees and random forests. These methods avoid the curse of dimensionality faced by kernel-based approaches, and allow one to draw on information from multiple state variables simultaneously. We apply the new models to four distinct empirical analyses, and in all applications the proposed new methods significantly outperform the baseline GAS model. In our applications to stock return volatility and density prediction, the optimal GAS tree model reveals a leverage effect and a variance risk premium effect. Our study of stock-bond dependence finds evidence of a flight-to-quality effect in the optimal GAS forest forecasts, while our analysis of high-frequency trade durations uncovers a volume-volatility effect

Age-related changes in egg yolk composition between conventional and organic table eggs

The aim of this study was to investigate fatty acids, fat-soluble vitamins, malondialdehyde and cholesterol in conventional and organic eggs obtained from hens of different ages (30 and 60 weeks). A total of 360 egg yolks were used in this study. Polyunsaturated fatty acid, omega-3, and omega-6 levels were higher in the organic eggs from the 30-week-old hens. The monounsaturated fatty acid level was higher in the conventional eggs but was the same between the two age groups. Cholesterol and vitamin A levels were not influenced by either the rearing system or the age of the hens. The malondialdehyde, vitamin D2, and vitamin K2 were higher in the organic eggs; however, vitamin E was higher in the conventional eggs. The results showed that the rearing system and age, as well as the diet, had an impact on the composition of the egg. Total levels of polyunsaturated fatty acid, omega-3, and omega-6 are higher in organic eggs produced by younger hens

Application of Some Proteome Analysis Techniques in Animal Reproduction

This chapter focuses on the application of proteome analysis techniques to animal reproduction and provides general information on one-dimensional (1D) and two-dimensional (2D) electrophoresis, chromatographic methods, and mass spectrometer (MS), widely used in proteomics studies. Proteome consists of an entire complement of proteins expressed by a cell, tissue, or organism. Proteomics reveals functions of proteins encoded in the genome. These functions include posttranslational modifications (PTMs) and alterations in the protein synthesis. Animal reproduction takes a key role in livestock, and increasing the reproduction rate in flocks plays an important role in livestock management. Studying the proteins related to reproduction could guide on how to increase fertility. Recent studies addressed the proteome constitution of both male and female reproductive system. Follicular fluid, endometrium, and ovary proteins were analyzed in females by proteomics study, while in males, sperm proteomics was more focused. Information obtained on this issue is also beneficial for the development of reproductive technologies such as in vitro fertilization and embryo transfer. Strategies to increase fertility in animals can be revealed by proteomic studies, and a more profound knowledge on proteomics may become helpful to develop and enhance the efficiency of reproductive technologies

Treatment of Hypoglycemia

Hypoglycemia is an important condition that can be seen in everyone, more often in those with diabetes mellitus, and can sometimes be life-threatening. Hypoglycemia is a condition that can be prevented with simple precautions. It is a simple procedure that can be done mostly by ordinary people when the treatment is known. The most important step in the treatment is the education of those at risk of hypoglycemia and their relatives. The first step in treatment is to measure blood glucose, if possible. If blood sugar is below 70 mg/dl, hypoglycemia is diagnosed; if it is below 50 mg/dl, it is called severe hypoglycemia. The first approach in a conscious patient is to give the patient 15 mg of carbohydrate and measure the blood glucose again after 15 minutes. If the measured value is <70 mg/dl, the procedure should be repeated. If possible, glucagon should be administered to unconscious, out-of-hospital hypoglycemic patients until emergency help arrives. If glucagon is not available, glucose gel can be applied to the buccal mucosa. 50 ml of 50% glucose IV is administered to an unconscious hypoglycemic patient in the hospital. If the blood sugar does not rise above 70 mg/dl, the procedure is repeated

Anatomical and functional outcomes of scleral buckling versus primary vitrectomy in pseudophakic retinal detachment

Retinal detachment is the separation of the sensory retina from the retinal pigment epithelium by subretinal fluid. There are several types of retinal re-attachment surgery, including scleral buckling (SB), pneumatic retinopexy, and vitrectomy (with or without SB). The objective of this study was to compare anatomical and visual outcomes between patients with pseudophakic rhegmatogenous retinal detachment (RRD) who underwent pars plana vitrectomy (PPV) with silicone oil (SO) or perfluoropropane (C3F8) gas tamponade and pseudophakic RRD patients who underwent SB surgery. We evaluated retrospectively 101 pseudophakic RRD patients from a single center. The patients were classified into three groups according to the surgical procedure performed: PPV + Silicone - patients who underwent PPV with SO tamponade; PPV + Gas - patients who underwent PPV with perfluoropropane gas tamponade; and SB group - patients who underwent SB surgery. The groups were compared with regard to primary and final anatomical and visual outcomes. The number of patients in PPV + Silicone, PPV + Gas, and SB group was 39 (38.6%), 32 (31.7%), and 30 (29.7%), respectively. The mean follow-up period in PPV + Silicone, PPV + Gas, and SB group was 33.95 ± 23.58, 32.62 ± 10.95, and 33.76 ± 16.62 months, respectively. No significant difference was observed between the groups neither with regard to primary and final anatomical and visual success rates nor in relation to the recurrence rate of retinal detachment. According to our anatomical and visual outcome results, either of the three methods (i.e., PPV + Silicone, PPV + Gas, or SB) can be used in the treatment of pseudophakic retinal detachment

Atrial electromechanical delay is impaired in patients with primary hyperparathyroidism

Introduction: Primary hyperparathyroidism (PHPT) is an endocrine disease that poses a risk for cardiac arrhythmias. Atrial electromechanical delay (EMD) has been known as an early marker of atrial fibrillation (AF). This study aimed to evaluate the atrial EMD in PHPT. Material and methods: Fifty PHPT patients (45 females, 5 males) aged 30–75 years and 38 controls (35 females, 3 males) aged 31–73 years were included in the study. Atrial EMD parameters were measured by using tissue Doppler imaging (TDI). Inter-atrial EMD was calculated as the difference between PA lateral and PA tricuspid; intra-atrial EMD was calculated as the difference between PA septum and PA tricuspid, and left-atrial EMD was calculated as the difference between PA lateral and PA septum. Results: Atrial EMD parameters (PA lateral, PA septum, PA tricuspid) significantly increased in the PHPT group compared to the control group (p &lt; 0.001, for all). Also, inter-atrial and intra-atrial EMD were higher in the PHPT group than in the control group (p &lt; 0.001, for all). In correlation analysis, calcium was closely associated with PA lateral (r = 0.749, p &lt; 0.001), PA septum (r = 0.735, p &lt; 0.001), inter-atrial EMD (r = 0.807, p &lt; 0.001), and intra-atrial EMD (r = 0.838, p &lt; 0.001). The same correlation relationship was seen between PTH levels with PA lateral (r = 671, p &lt; 0.001), PA septum (r = 0.660, p &lt; 0,001), inter-atrial EMD (r = 0.674, p &lt; 0.001), and intra-atrial EMD (r = 0.732, p &lt; 0.001). Conclusions: Atrial EMD parameters were prolonged in PHPT. The measurement of atrial EMD parameters might be used in determining the risk of AF development in PHPT

Etiopathogenesis of Sheehan’s Syndrome: Roles of Coagulation Factors and TNF-Alpha

Sheehan’s Syndrome (SS) is defined as pituitary hormone deficiency due to ischemic infarction of the pituitary gland as a result of massive postpartum uterine hemorrhage. Herein, we aimed to investigate the roles of Factor II (G20210A), Factor V (G1691A), MTHFR (C677T and A1298C), PAI-1 4G/5G, and TNF-α (-308  G>A) gene polymorphisms in the etiopathogenesis of SS. Venous blood samples were obtained from 53 cases with SS and 43 healthy women. Standard methods were used to extract the genomic DNAs. Factor II (G20210A), Factor V (G1691A), and MTHFR (C677T and A1298C) polymorphisms were identified by real-time PCR. PAI-1 4G/5G and TNF-α (-308  G>A) gene polymorphisms were detected with polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) methods. According to statistical analysis, none of the polymorphisms were found to be significantly higher in the SS group compared to the control group. Hence, we suggest that genetic factors other than Factor II, Factor V, MTHFR, PAI-1, and TNF-α gene polymorphisms should be researched in the etiopathogenesis of SS