Fuelling conditions at staging sites can mitigate Arctic warming effects in a migratory bird

© 2018, The Author(s). Under climate warming, migratory birds should align reproduction dates with advancing plant and arthropod phenology. To arrive on the breeding grounds earlier, migrants may speed up spring migration by curtailing the time spent en route, possibly at the cost of decreased survival rates. Based on a decades-long series of observations along an entire flyway, we show that when refuelling time is limited, variation in food abundance in the spring staging area affects fitness. Bar-tailed godwits migrating from West Africa to the Siberian Arctic reduce refuelling time at their European staging site and thus maintain a close match between breeding and tundra phenology. Annual survival probability decreases with shorter refuelling times, but correlates positively with refuelling rate, which in turn is correlated with food abundance in the staging area. This chain of effects implies that conditions in the temperate zone determine the ability of godwits to cope with climate-related changes in the Arctic

BTF-based Material Representations: Current Challenges

The development of Bidirectional Texture Functions (BTFs) has made it possible for a wide range of different materials to acquire their characteristic appearance from a real-world counterpart and reproduce it faithfully in a high-quality rendering, that is hard to distinguish from an actual photograph. However, they have not yet found wide-spread use in practical applications. In this paper, we discuss, from our point of view, the main reasons for this and which unanswered questions and challenges for future research in this area remain. We focus on three different aspects: How can BTFs be measured and represented more efficiently? How can they be edited intuitively? And finally, can we find a perceptual difference metric between materials?Eurographics Workshop on Material Appearance Modelin

An investigation into the snack-food market in the Western Cape

Thesis (M. Comm.) -- University of Stellenbosch, 1988.Full text to be digitised and attached to bibliographic record

Atlantis, a utopian nightmare

Resettlement, forced removal

Atlantis, a utopian nightmare

Resettlement, forced removal

Telomerase activity in needle biopsies from prostate cancer and benign prostates

Background Telomerase activation is thought to be essential for the immortality of cancer cells. It may be a prognostic factor in small volume well differentiated prostate cancers and hence a guide for the aggressiveness of the approach. The length of the chromosome tips (telomeres) are maintained by a specific enzyme (telomerase) independently of the normal cell division cycle. Although telomerase is not expressed in most normal human tissues, it is expressed in most human tumours. For the detection of telomerase in small prostate needle biopsy samples a recently developed telomeric repeat amplification protocol (TRAP) assay was used. The aim of the present study was: to measure telomerase activity in human prostate samples, and to evaluate the applicability of this assay on specimens from a prostate biopsy. Materials and methods From 36 patients referred for lower urinary tract symptoms (LUTS) or suspicion of having prostate cancer a total of 288 prostate biopsy samples were obtained (8 in each patient). When the digital rectal examination was abnormal and/or when the PSA level was elevated in L.U.T.S., or asymptomatic patients' tissue samples were obtained by transrectal ultrasound (TRUS) guided biopsies. Samples were tested for telomerase activity by a modified TRAP and forwarded for histology. Results In 19 out of 36 patients prostate cancer was diagnosed on histology. In 11 of these 19 tumours substantial telomerase activity was detected, whereas only very low telomerase activity existed in 2 of 17 samples from benign prostatic hypertrophy (BPH) patients. In this small series the relative telomerase activity in prostate cancer correlated with histopathological grade. Conclusions Our results show the applicability of a TRAP assay to measure telomerase activity in small needle biopsied prostate samples. In poorly differentiated and metastatic cancer we observed that levels of telomerase activity were high. To establish accuracy and to distinguish the 'relative good from the ugly' further study is needed