Windows on language evolution: How are they constructed?

No abstract

Thermal analysis of the LLR optical telescope tube assembly based in Hartebeesthoek Radio Astronomy Observatory

The Hartebeesthoek Radio Astronomy Observatory of South Africa is currently developing a lunar laser ranger (LLR) system based on a one metre aperture telescope in collaboration with National Aeronautics and Space Administration and the Observatoire de la Côte d’Azur. This LLR will be an addition to a limited list of operating LLR stations globally and it is expected to achieve sub-centimetre range precision to the Moon. Key to this expectation including the overall telescope operational performance is thermal analysis of the telescope structure, based on the thermal properties of component materials and their interaction with the environment through conventional heat transfer mechanisms. This paper presents transient thermal simulation results of the telescope’s optical tube and one metre primary mirror in terms of thermal variations and consequent structural deformations. The results indicate that on a non-windy, cloud-free and winter day, the temperature gradients on the structure could be within 1 °C with respect to the temporal ambient air temperatures at the site when these are between 9 and 23 °C. Furthermore, these gradients were coupled with thermally-induced total deformations that vary between 2.9 and 40.7 μm of the assembled telescope components. In overall, these findings suggest that both the tube and especially the mirror may respond very slowly to ambient temperatures; however, correcting for structural thermal variations is imperative in maximizing the pointing accuracy of the telescope thereby increasing the chance being on-target with the retroreflectors located on the Moon surface.P. L. Tsela hereby acknowledges research support in part by the National Research Foundation of South Africa for the grant, Unique Grant No. 93952.http://link.springer.com/journal/403282017-09-30hb2016Geography, Geoinformatics and Meteorolog

Liver transplantation for non-resectable colorectal liver metastases at a single centre in South Africa: A report of the ethics and regulatory approval process

Non-resectable colorectal liver metastases (CLMs) are generally considered an absolute contraindication for liver transplantation. However, a 2013 Norwegian study transplanted livers in 21 patients with CLMs and reported excellent outcomes. The current article reports on the deliberations of the Wits Human Research Ethics Committee (Medical), which resulted in approval of the first liver transplant for a patient with CLMs in South Africa (SA). Factors considered included the scarcity of donor organs in SA, weighing the best interests of different groups of patients and the requirement for extensive and careful information provision. Originally under the auspices of Section 37 of the World Medical Association Declaration of Helsinki (2013), the protocol has now been formalised as a research project

The new SPIL logo: A face for the future

No abstract

Evaluation of the two-photon absorption characteristics of GaSb/GaAs quantum rings

The optical parameters describing the sub-bandgap response of GaSb/GaAs quantum rings solar cells have been obtained from photocurrent measurements using a modulated pseudomonochromatic light source in combination with a second, continuous photo-filling source. By controlling the charge state of the quantum rings, the photoemission cross-sections describing the two-photon sub-bandgap transitions could be determined independently. Temperature dependent photo-response measurements also revealed that the barrier for thermal hole emission from the quantum rings is significantly below the quantum ring localisation energy. The temperature dependence of the sub-bandgap photo-response of the solar cell is also described in terms of the photo-and thermal-emission characteristics of the quantum rings. (C) 2014 AIP Publishing LLC

Pre-operative Planning and Intra-operative Guidance for Shoulder Replacement Surgery

Shoulder joint replacement, or arthroplasty, is indicated in cases where arthritis or trauma has resulted in severe joint damage that in turn causes increased pain and decreased function. However, shoulder arthroplasty is less successful than hip and knee replacement, mostly due to the complexity of the shoulder joint and the resultant complexity of the replacement operation. In this paper we present a complete visualization-oriented pre-operative planning and intra-operative guidance approach for shoulder joint replacement. Our system assists the surgeon by allowing a virtual arthroplasty procedure whilst giving feedback, primarily via patient- and procedure-specific joint range of motion (ROM) simulation and visualization. After a successful planning, our system automatically generates a 3D model of a patient-specific mechanical guidance device that is then produced by a rapid prototyping machine and can be used during the operation. In this way, a computer-based guidance system is not required in the operating room

Favourable outcomes for the first 10 years of kidney and pancreas transplantation at Wits Donald Gordon Medical Centre, Johannesburg, South Africa

Background. It is important for centres participating in transplantation in South Africa (SA) to audit their outcomes. Wits Donald Gordon Medical Centre (WDGMC), Johannesburg, SA, opened a transplant unit in 2004. The first 10 years of kidney and pancreas transplantation were reviewed to determine outcomes in respect of recipient and graft survival.Methods. A retrospective review was conducted of all kidney-alone and simultaneous kidney-pancreas (SKP) transplants performed at WDGMC from 1 January 2004 to 31 December 2013, with follow-up to 31 December 2014 to ensure at least 1 year of survival data. Information was accessed using the transplant registers and clinical records in the transplant clinic at WDGMC. The Kaplan-Meier method was used to estimate 1-, 5- and 10-year recipient and graft survival rates for primary (first graft) kidney-alone and SKP transplants.Results. The overall 10-year recipient and graft survival rates were 80.4% and 66.8%, respectively, for kidney-alone transplantation. In the kidney-alone group, children tended towards better recipient and graft survival compared with adults, but this was not statistically significant. In adults, recipient survival was significantly better for living than deceased donor type. Recipient and graft survival were significantly lower in black Africans than in the white (largest proportion in the sample) reference group. For SKP transplants, the 10-year recipient survival rate was 84.7%, while kidney and pancreas graft survival rates were 73.1% and 43.2%, respectively.Conclusion. Outcomes of the first 10 years of kidney and pancreas transplantation at WDGMC compare favourably with local and international survival data

The ‘Galilean Style in Science’ and the Inconsistency of Linguistic Theorising

Chomsky’s principle of epistemological tolerance says that in theoretical linguistics contradictions between the data and the hypotheses may be temporarily tolerated in order to protect the explanatory power of the theory. The paper raises the following problem: What kinds of contradictions may be tolerated between the data and the hypotheses in theoretical linguistics? First a model of paraconsistent logic is introduced which differentiates between week and strong contradiction. As a second step, a case study is carried out which exemplifies that the principle of epistemological tolerance may be interpreted as the tolerance of week contradiction. The third step of the argumentation focuses on another case study which exemplifies that the principle of epistemological tolerance must not be interpreted as the tolerance of strong contradiction. The reason for the latter insight is the unreliability and the uncertainty of introspective data. From this finding the author draws the conclusion that it is the integration of different data types that may lead to the improvement of current theoretical linguistics and that the integration of different data types requires a novel methodology which, for the time being, is not available

The ‘Galilean Style in Science’ and the Inconsistency of Linguistic Theorising

Chomsky’s principle of epistemological tolerance says that in theoretical linguistics contradictions between the data and the hypotheses may be temporarily tolerated in order to protect the explanatory power of the theory. The paper raises the following problem: What kinds of contradictions may be tolerated between the data and the hypotheses in theoretical linguistics? First a model of paraconsistent logic is introduced which differentiates between week and strong contradiction. As a second step, a case study is carried out which exemplifies that the principle of epistemological tolerance may be interpreted as the tolerance of week contradiction. The third step of the argumentation focuses on another case study which exemplifies that the principle of epistemological tolerance must not be interpreted as the tolerance of strong contradiction. The reason for the latter insight is the unreliability and the uncertainty of introspective data. From this finding the author draws the conclusion that it is the integration of different data types that may lead to the improvement of current theoretical linguistics and that the integration of different data types requires a novel methodology which, for the time being, is not available