Exploration of the functional consequences of fixational eye movements in the absence of a fovea.

A recent theory posits that ocular drifts of fixational eye movements serve to reformat the visual input of natural images, so that the power of the input image is equalized across a range of spatial frequencies. This "spectral whitening" effect is postulated to improve the processing of high-spatial-frequency information and requires normal fixational eye movements. Given that people with macular disease exhibit abnormal fixational eye movements, do they also exhibit spectral whitening? To answer this question, we computed the power spectral density of movies of natural images translated in space and time according to the fixational eye movements (thus simulating the retinal input) of a group of observers with long-standing bilateral macular disease. Just as for people with normal vision, the power of the retinal input at low spatial frequencies was lower than that based on the 1/f2 relationship, demonstrating spectral whitening. However, the amount of whitening was much less for observers with macular disease when compared with age-matched controls with normal vision. A mediation analysis showed that the eccentricity of the preferred retinal locus adopted by these observers and the characteristics of ocular drifts are important factors limiting the amount of whitening. Finally, we did not find a normal aging effect on spectral whitening. Although these findings alone cannot form a causal link between macular disease and spectral properties of eye movements, they suggest novel potential means of modifying the characteristics of fixational eye movements, which may in turn improve functional vision for people with macular disease

Suboptimal eye movements for seeing fine details.

Human eyes are never stable, even during attempts of maintaining gaze on a visual target. Considering transient response characteristics of retinal ganglion cells, a certain amount of motion of the eyes is required to efficiently encode information and to prevent neural adaptation. However, excessive motion of the eyes leads to insufficient exposure to the stimuli, which creates blur and reduces visual acuity. Normal miniature eye movements fall in between these extremes, but it is unclear if they are optimally tuned for seeing fine spatial details. We used a state-of-the-art retinal imaging technique with eye tracking to address this question. We sought to determine the optimal gain (stimulus/eye motion ratio) that corresponds to maximum performance in an orientation-discrimination task performed at the fovea. We found that miniature eye movements are tuned but may not be optimal for seeing fine spatial details

Motion Information via the Nonfixating Eye Can Drive Optokinetic Nystagmus in Strabismus

Purpose: Strabismic patients can perceptually suppress information from one eye to avoid double vision. However, evidence from prior studies shows that some parts of the visual field of the deviated eye are not suppressed. Our goal here was to investigate whether motion information available only to the deviated eye can be utilized by the oculomotor system to drive eye movements. Methods: Binocular eye movements were acquired in two exotropic monkeys in a dichoptic viewing task in which the fixating eye viewed a stationary spot and the deviated eye viewed a 10° × 10° stationary patch that contained a drifting grating stimulus moving at 10°/s to the right or left for 20 seconds. Spatial location and contrast of the grating were systematically varied in subsequent trials. For each trial, mean slow-phase velocity of the optokinetic nystagmus (OKN) elicited by grating motion was calculated. Results: We found that OKN responses can be elicited by a motion stimulus presented to the foveal region of the deviated eye. Optokinetic nystagmus magnitude varied depending on which eye was viewing the drifting grating and correlated well with fixation preference and fixation stability (indicators of amblyopia). The magnitude of OKN increased for increased relative contrast of the motion stimulus compared to the fixation spot. Conclusions: Our results show that motion information available only to the deviated eye can drive optokinetic eye movements. We conclude that the brain has access to visual information from portions of the deviated eye (including the fovea) in strabismus that it can use to drive eye movements

A study on the differentiation and the development of floral parts in grapes (Vitis vinifera L. var.)

Investigations on differentiation and development of floral parts in Vitis vinifera were conducted in 1967 and 1968 under Ankara conditions. Materials were Hasandede, Kalecik karasi and Papaz karasi varieties, which were grafted on Chasselas X V. berlandieri 41 B M.G. rootstocks. The results obtained can be summarized as follows:The differentiation time of floral parts is different in the three varieties.Not all flowers of one inflorescence have the same stages of development.The differentiation of floral parts initiated with the calyx in cluster primordia. The calyx can be noticed at the beginning of August in Hasandede and Kalecik karasi, at the end of August or the beginning of September in Papaz karasi.The differentiation and development of the sepals (calyx), petals (corolla), stamens and pistil is in the order named. All the essential flower parts were formed within 10-15 days of the appearance of the inflorescence after budburst

Perceptions of the Dilemma – Order versus Freedom at Managing Faculty: A Literature Review

This study aims to examine the perceptions of the middle management (deans and heads of departments) and academicians on the dilemma order versus freedom at faculty management. It discusses how this dilemma is seen at an operational level and how it can be managed at university where both parties -with a managerial role or not- are academicians/academics and have professional expertise. The literature on organizational dilemmas was analyzed to answer the questions “which side of the dilemma is seen dominantly in different organization types?”, “how does examining organizational structures from different perspectives help understand educational organizations?” and “in that way how can dilemmas be managed in educational contexts especially in the academic context?” The major findings include the tendency to one side of the dilemma in different perspectives to organizational structure creates problems in the organizational management. However, balancing the order or freedom dilemma at an operational level improves effectiveness. Balancing dilemmas at faculty management is specifically difficult due to differing perceptions of academicians and the management. It needs the effective usage of other instruments in organizational life. The dynamics of organizational structures and processes in Higher Education (HE) institutions are growing attention due to the growing importance of HE institutions worldwide. Research on how effectively the operating core itself at HE institutions is managed is becoming more important in the field. This study explores the problems in the management of faculty at an operational level based on dilemmas between academicians and the middle management. Keywords: Dilemmas, Faculty management, Middle managemen

Efficacy, Tolerability, and Acceptability of Iron Hydroxide Polymaltose Complex versus Ferrous Sulfate: A Randomized Trial in Pediatric Patients with Iron Deficiency Anemia

Iron polymaltose complex (IPC) offers similar efficacy with superior tolerability to ferrous sulfate in adults, but randomized trials in children are rare. In a prospective, open-label, 4-month study, 103 children aged >6 months with iron deficiency anemia (IDA) were randomized to IPC once daily or ferrous sulfate twice daily, (both 5 mg iron/kg/day). Mean increases in Hb to months 1 and 4 with IPC were 1.2 ± 0.9 g/dL and 2.3 ± 1.3 g/dL, respectively, (both P = 0.001 versus baseline) and 1.8 ± 1.7 g/dL and 3.0 ± 2.3 g/dL with ferrous sulfate (both P = 0.001 versus baseline) (n.s. between groups). Gastrointestinal adverse events occurred in 26.9% and 50.9% of IPC and ferrous sulfate patients, respectively (P = 0.012). Mean acceptability score at month 4 was superior with IPC versus ferrous sulfate (1.63 ± 0.56 versus 2.14 ± 0.75, P = 0.001). Efficacy was comparable with IPC and ferrous sulfate over a four-month period in children with IDA, but IPC was associated with fewer gastrointestinal adverse events and better treatment acceptability

Neopterin and Soluble Urokinase Type Plasminogen Activator Receptor as Biomarkers in Dogs with Systemic Inflammatory Response Syndrome

ΔΕΝ ΔΙΑΤΙΘΕΤΑΙ ΠΕΡΙΛΗΨΗThe systemic inflammatory response syndrome (SIRS) is a common cause of mortality in dogs. This study aims to investigate the diagnostic value of markers C-reactive protein (CRP), soluble urokinase-type plasminogen activator receptor (suPAR) and neopterin in dogs with SIRS. The materials of the study consist of 30 dogs with SIRS and 15 healthy dogs that show no clinical symptom, 45 dogs in total. CRP, suPAR and neopterin levels of the serum samples were determined by ELISA using commercial kits. In the study, it was found that CRP, suPAR and neopterin levels of dogs with SIRS were significantly higher (P < 0.001, P < 0.01 and P < 0.01, respectively) than those in the healthy group. The cut-off values for the healthy dogs and dogs with SIRS for CRP, suPAR and neopterin were determined to be 11.20 mg/L, 223.68 ng/L and 3.23 nmol/mL, respectively. At these cut-off values, sensitivity levels were determined as high (92.90%) for CRP, moderate (63.30%) for neopterin, and low (53.30%) for suPAR, and high specificities (93.30%) were determined for all. In conclusion, it was determined that CRP showed the best performance for the detection of systemic inflammatory response in dogs and neopterin and suPAR could be used as an alternative to CRP. It was also argued that further studies were necessary in order to determine diagnosis and prognosis of diseases

Brief ampelographic characterization of indigenous grapevine cultivars subjected to clonal selection in Turkey

A unique national clonal selection programme is still being conducted on 24 indigenous table (15 white, 6 black, 3 red), 16 wine (7 white, 9 red) and 4 raisin (2 white seedless, 2 white seeded) grape cultivars in 9 agricultural regions of Turkey. As the results of this programme, 127 candidate clones belonging to 13 cultivars have been selected This paper also includes a brief ampelographic description of the indigenous Turkish grape cultivars subjected to clonal selection, based mainly on fruit characteristics, growth, productivity and ripening periods in their primary locations

Incoterms 2020

The Incoterms (R) are internationally accepted standards defined by the International Chamber of Commerce (ICC) and is a trademark of ICC, which define the responsibilities of sellers and buyers depending on how the goods are delivered in sales contracts. These international resources were created to eliminate the differences of interpretation and to accurately and fairly share the costs and risks of goods delivery. The latest version of these rules was enforced from January 01, 2020. With the appropriate consideration for the current commercial practices, the Incoterms (R) 2020 rules aim to be useful to the practitioners by updating the previous version of the Incoterms (R) 2010 rules. Thus, Incoterms (R) 2020 amended one of the existing terms and enriched the content of some terms. In our article, we have attempted to demonstrate the type of changes occurring for each item for different types of delivery in the Incoterms (R) 2020