66 research outputs found
Forecasting The Exchange Rate Series With Ann: The Case Of Turkey
As it is possible to model both linear and nonlinear structures in time series by using Artificial Neural Network (ANN), it is suitable to apply this method to the chaotic series having nonlinear component. Therefore, in this study, we propose to employ ANN method for high volatility Turkish TL/US dollar exchange rate series and the results show that ANN method has the best forecasting accuracy with respect to time series models, such as seasonal ARIMA and ARCH models. The suggestions about the details of the usage of ANN method are also made for the exchange rate of Turkey.Activation function, ARIMA, ARCH, Artificial neural network, Chaotic series, Exchange rate, Forecasting, Time series
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
Metronomic Chemotherapy
Metronomic chemotherapy, continuous and dose-dense administration of chemotherapeutic drugs with lowered doses, is being evaluated for substituting, augmenting, or appending conventional maximum tolerated dose regimens, with preclinical and clinical studies for the past few decades. To date, the principle mechanisms of its action include impeding tumoral angiogenesis and modulation of hosts' immune system, affecting directly tumor cells, their progenitors, and neighboring stromal cells. Its better toxicity profile, lower cost, and easier use are main advantages over conventional therapies. The evidence of metronomic chemotherapy for personalized medicine is growing, starting with unfit elderly patients and also for palliative treatment. The literature reviewed in this article mainly demonstrates that metronomic chemotherapy is advantageous for selected patients and for certain types of malignancies, which make it a promising therapeutic approach for filling in the gaps. More clinical studies are needed to establish a solidified role for metronomic chemotherapy with other treatment models in modern cancer management.PubMedWoSScopu
Thymoma with an incidental benign laryngeal mass mimicking laryngeal carcinoma: Case report
SIMSEK, GOKCE/0000-0001-5281-0986WOS: 000370834200006PubMed: 26930331Thymic carcinomas are rarely seen. Because of recurrent laryngeal nerve involvement, hoarseness is a common presenting symptom. Persistent hoarseness in a male smoker past his fifth decade is also a distinctive symptom for laryngeal carcinoma. Stroboscopic laryngeal examination and biopsy are required for the diagnosis. In this article we describe a case involving a patient with thymic carcinoma who, interestingly, also presented with a benign laryngeal mass with unilateral vocal fold fixation. We emphasize the importance of keeping in mind nonlaryngeal pathologies invading the recurrent laryngeal nerve in patients with persistent hoarseness and a nonspesific laryngeal mass
Negative Corneal Fluorescein Staining as an Exceptionally Early Sign of Acanthamoeba Keratitis: A Case Report
Objectives: To report the negative fluorescein staining as an early sign of Acanthamoeba keratitis (AK). Methods: Case report and brief review of related literature. Report of Case: A 30-year-old, contact lens wearer, woman presented with mild irritation and pain in the right eye. The best-corrected visual acuity (BCVA) was 20/20 in both eyes. Slit-lamp examination revealed a peripheral corneal infiltration. Empirical antimicrobial therapy was initiated. Within the third day, peripheral corneal opacity regressed but a Y-shaped linear epitheliopathy with a negative fluorescein staining, because of a ridge-like epithelial irregularity, was observed in the central cornea. Clinical findings progressed rapidly. Confocal microscopy revealed hyper-reflective cysts with the typical double-ring sign consistent with AK. Therefore, topical chlorhexidine and propamidine were initiated. Clinical findings regressed subsequently. The final BCVA was 20/20 in both eyes. Conclusion: Acanthamoeba keratitis usually manifest as superficial epitheliopathy and progresses to the stroma. Findings may be obscure or atypical; comprehensive and careful examination may reveal mild findings in the early stages
Salivary and Lacrimal Gland Alterations of the Epidermal Fatty Acid-Binding Protein (E-FABP) in Non-Obese Diabetic Mice
The purpose of this study was to investigate the changes in E-FABP in the salivary and lacrimal glands of the Sjögren syndrome (SS) model non-obese diabetic mice (NOD). Cotton thread and ocular vital staining tests were performed on 10-week NOD male mice (n = 24) and age- and sex-matched wild-type (WT) mice (n = 25). Tear and saliva samples were collected at sacrifice for E-FABP ELISA assays. Salivary and lacrimal gland specimens underwent immunohistochemistry stainings for E-FABP. Real-time RT-PCR was also performed for the quantification of mRNA expression levels in the salivary and lacrimal glands. Corneal vital staining scores in the NOD mice were significantly higher compared with those for the wild-type mice (p = 0.0001). The mean tear E-FABP level showed a significantly lower concentration in the NOD mice (p = 0.001). The mean saliva E-FABP level also showed a significantly lower concentration in the NOD mice (p = 0.04). Immunohistochemistry revealed intense E-FABP staining in the LG acinar epithelium and less intense staining in the acinar epitheliae of the SGs in the NOD mice compared to the WT mice. Real-time RT-PCR for the mRNA expression of E-FABP showed a significantly decreased expression in the SG and a significant increase in the LG of the NOD mice compared to the WT mice. In conclusion, the E-FABP showed marked alterations in the tear film, saliva, lacrimal, and salivary glands of the NOD mouse, which may help explain the ocular surface changes in relation to the dry eye disease in this SS model mouse and keratoconjunctivitis sicca in SS patients
- …