The Role of Computer Modeling in Enhancing Students' Conceptual Understanding of Physics

The purpose of this study was to investigate how the use of the computer simulations program VPython facilitated students’ conceptual understanding of fundamental physical principles and in constructing new knowledge of physics. We focused on students in a calculus-based introductory physics course, based on the Matter and Interactions curriculum of Chabay & Sherwood (2002) at a large state engineering and science university in the USA. A major emphasis of this course was on computer modeling by using VPython to write pro¬grams simulating physical systems. We conducted multiple student interviews, as well as an open-ended exit survey, to find out student views on how creating their own simulations to enhanced-conceptual understanding of physics and in constructing new knowledge of phys¬ics. The results varied in relation to the phases when the interviews were conducted. At the beginning of the course, students viewed the simulation program as a burden. However, dur¬ing the course, students stated that it promoted their knowledge and better conceptual understanding of physical phenomena. We deduce that VPython computer simulations can improve students’ conceptual understanding of fundamental physical concepts and promote construction of new knowledge in physics, once they overcome the initial learning curve associated with the VPython software package

Surgical amniotic membrane transplantation after conjunctival and limbal tumor excision

Purpose: To evaluate the clinical results of patients treated by amniotic membrane transplantation (AMT) following excision of conjunctival and limbal tumors. Methods: A total of 14 eyes of 14 patients who underwent AMT after total lesion-free tumor excision and perilesional cryotherapy were evaluated. Results: The excised tumors comprised 7 conjunctival intraepithelial neoplasia, 5 conjunctival nevus, 1 primary acquired melanosis, and 1 squamous cell carcinoma. Limbus was involved in 10 cases, whereas cornea was involved in 6 cases. The average measurement of the tumor base was 14.8 mm (range 6-20 mm, SD 16 mm). The mean follow-up time period was 17.5 months (range 6 -60 months, SD 20 months). Complete healing occurred in eight eyes, but limbal cell deficiency developed in two eyes. Four cases had recurrence and were treated with the same surgical and medical procedures; during follow-up after recurrence, superficial peripheral vascularization and corneal scar were noted to have developed. Conclusions: AMT was effective for reconstruction of tissue defect after excision and cryotherapy of limbal and conjunctival tumors. In most of these cases, complete healing was achieved with a smooth, stable, and translucent surface

Hybrid contact lenses for visual management of patients after keratoplasty

Aim: This study aims to report the outcomes of new‑generation hybrid contact lenses for visual rehabilitation of postkeratoplasty patients.Materials and Methods: Twenty eyes of twenty postkeratoplasty patients were fitted with hybrid lenses. Each patient’s keratometric values, ocular surface irregularity indices, central corneal thickness (CCT), uncorrected visual acuity (UCVA),  spectacle‑corrected visual acuity, contact lens‑corrected visual acuity, contact lens fitting data, and contact lens daily wearing time were recorded. Follow‑up  examinations were performed at 1st week, 1st month, and 3rd month visit after successful fitting of the lenses.Results: The mean age of the patients was 38.42 ± 4.89 years. The mean spherical component of refractive error was −4.46 ± 2.1 D, and the mean astigmatism was −5.31 ± 1.55 D. The median UCVA was 1.00 logarithm of the minimum angle of resolution (logMAR) which improved to 0.40 logMAR after spectacle correction. The median visual acuity with hybrid contact lenses was 0.05 logMAR. The median CCT was 544.4 μm and increased to 549.2 μm at 3 months after contact lens wear. The difference was not statistically significant (P = 0.38). The mean follow‑up of patients was 4.32 ± 0.45 months. Eighteen of twenty patients reported a mean of 8.37 ± 1.95 h comfortable wearing time per day during this period. Two patients  discontinued contact lens wearing due to conjunctival hyperemia. No graft‑related complications such as decompensation, rejection, and infection were documented during the follow‑up period.Conclusion: The new‑generation hybrid contact lenses can be considered helpful in the visual management of postcorneal graft patients, particularly who are unable to achieve an adequate visual outcome with spectacles. Keywords: Contact lens complications, hybrid contact lens, irregular cornea, penetrating keratoplasty, postkeratoplasty astigmatis

Rethinking our understanding of diagrams

The role and value of diagrams in advancing human knowledge throughout history is evident in the literature. However, persistent evidence from the research and practitioner communities from across a range of disciplines points to difficulties and problems with understanding and using diagrams. Whether it is at the application level or as an abstract definition, our existing frameworks for understanding diagrams reduce the full meaning of diagrams to a single perspective or emphasis. This paper advocates placing multi-aspectual human functioning in a central role in the development of an enriched meta-approach to understanding diagrams. Two such aspects, namely, the spatial and symbolic, are essential to the understanding of diagrams across applications. The philosophical underpinnings and practical contributions of this approach to dealing with long standing problems of diagrams are discussed

First report of bacterial leaf spot caused by Xanthomonas axonopodis pv. begoniae, on begonia in Turkey

[No abstract available

Ocular Behcet's disease presenting with retinal tear and panuveitis

WOS: 000260917500017PubMed: 18344955

Changing indications and techniques for corneal transplantations at a tertiary referral center in Turkey, from 1995 to 2014

Yesim Altay, Ayse Burcu, Gozde Aksoy, Evin Singar Ozdemir, Firdevs Ornek Department of Ophthalmology, Ankara Training and Research Hospital, Ankara, Turkey Background: Indications for corneal transplantation in developed and developing nations differ according to the different spectrum of corneal disease in each country. Objective: The purpose of this study is to analyze the changing indications and surgical techniques for corneal transplantation over the past 20 years at a tertiary referral center in Turkey. Methods: We retrospectively reviewed the records of patients who underwent keratoplasty from January 1995 to December 2014 (between 1995 and 2004, period 1, and between 2005 and 2014, period 2). Patients’ demographic data, indications for corneal transplantation, and the type of surgery were recorded. Results: The number of keratoplasties performed ranged from 548 in period 1 to 782 in period 2. Between 1995 and 2004, the leading indications were keratoconus (34.1%), bullous keratopathy (17%), and non-herpetic corneal scar (13.3%), and between 2005 and 2014, they were keratoconus (33.8%), corneal stromal dystrophy (14.2%), and bullous keratopathy (12.7%). All the keratoplasties performed in the 1995–2004 period were penetrating keratoplasty (PKP). During the period 2005–2014, PKP accounted for 93%, automated lamellar keratoplasty 5.8%, and deep anterior lamellar keratoplasty 1.2% of all corneal transplantations. Conclusion: Keratoconus was the leading indication for keratoplasty in both periods. In the 2005–2014 period, corneal stromal dystrophy increased significantly. All the keratoplasties performed in period 1 and 93% of all keratoplasties performed in period 2 were PKP. Keywords: corneal transplantation, indication, keratoconus, keratoplasty technique, pene­trating keratoplast