Cooperative Research Centre

About: Cooperative Research Centre is a based out in . It is known for research contribution in the topics: Population & Sea ice. The organization has 7633 authors who have published 8607 publications receiving 429721 citations.

Stochastic generation of annual, monthly and daily climate data: A review

Abstract: . The generation of rainfall and other climate data needs a range of models depending on the time and spatial scales involved. Most of the models used previously do not take into account year to year variations in the model parameters. Long periods of wet and dry years were observed in the past but were not taken into account. Recently, Thyer and Kuczera (1999) developed a hidden state Markov model to account for the wet and dry spells explicitly in annual rainfall. This review looks firstly at traditional time series models and then at the more complex models which take account of the pseudo-cycles in the data. Monthly rainfall data have been generated successfully by using the method of fragments. The main criticism of this approach is the repetitions of the same yearly pattern when only a limited number of years of historical data are available. This deficiency has been overcome by using synthetic fragments but this brings an additional problem of generating the right number of months with zero rainfall. Disaggregation schemes are effective in obtaining monthly data but the main problem is the large number of parameters to be estimated when dealing with many sites. Several simplifications have been proposed to overcome this problem. Models for generating daily rainfall are well developed. The transition probability matrix method preserves most of the characteristics of daily, monthly and annual characteristics and is shown to be the best performing model. The two-part model has been shown by many researchers to perform well across a range of climates at the daily level but has not been tested adequately at monthly or annual levels. A shortcoming of the existing models is the consistent underestimation of the variances of the simulated monthly and annual totals. As an alternative, conditioning model parameters on monthly amounts or perturbing the model parameters with the Southern Oscillation Index (SOI) result in better agreement between the variance of the simulated and observed annual rainfall and these approaches should be investigated further. As climate data are less variable than rainfall, but are correlated among themselves and with rainfall, multisite-type models have been used successfully to generate annual data. The monthly climate data can be obtained by disaggregating these annual data. On a daily time step at a site, climate data have been generated using a multisite type model conditional on the state of the present and previous days. The generation of daily climate data at a number of sites remains a challenging problem. If daily rainfall can be modelled successfully by a censored power of normal distribution then the model can be extended easily to generate daily climate data at several sites simultaneously. Most of the early work on the impacts of climate change used historical data adjusted for the climate change. In recent studies, stochastic daily weather generation models are used to compute climate data by adjusting the parameters appropriately for the future climates assumed.

Apical membrane antigen 1 plays a central role in erythrocyte invasion by Plasmodium species

Abstract: Apical membrane antigen 1 (AMA1) is an asexual blood-stage protein expressed in the invasive merozoite form of Plasmodia species, which are the causative agent of malaria. We have complemented the function of Plasmodium falciparum AMA1 (PfAMA1) with a divergent AMA1 transgene from Plasmodium chabaudi (PcAMA1). It was not possible to disrupt the PfAMA1 gene using 'knock-out' plasmids, although we demonstrate that the PfAMA1 gene can be targeted by homologous recombination. These experiments suggest that PfAMA1 is critical, perhaps essential, for blood-stage growth. Importantly, we showed that PcAMA1 expression in P. falciparum provides trans-species complementation to at least 35% of the function of endogenous PfAMA1 in human red cells. Furthermore, expression of this transgene in P. falciparum leads to more efficient invasion of murine erythrocytes. These results indicate an important role for AMA1 in the invasion of red blood cells (RBCs) across divergent Plasmodium species.

Decrease in rate of myopia progression with a contact lens designed to reduce relative peripheral hyperopia: one-year results.

Abstract: PURPOSE. To determine whether a novel optical treatment using contact lenses to reduce relative peripheral hyperopia can slow the rate of progress of myopia. METHODS. Chinese children, aged 7 to 14 years, with baseline myopia from sphere 0.75 to 3.50 D and cylinder 1.00 D, were fitted with novel contact lenses (n 45) and followed up for 12 months, and their progress was compared with that of a group (n 40) matched for age, sex, refractive error, axial length, and parental myopia wearing normal, single-vision, spherocylindrical spectacles. RESULTS. On adjusting for parental myopia, sex, age, baseline spherical equivalent (SphE) values, and compliance, the estimated progression in SphE at 12 months was 34% less, at 0.57 D, with the novel contact lenses (95% confidence interval [CI], 0.45 0.69 D) than at 0.86 D, with spectacle lenses (95% CI, 0.74 to 0.99 D). For an average baseline age of 11.2 years, baseline SphE of 2.10 D, a baseline axial length of 24.6 mm, and 320 days of compliant lens wear, the estimated increase in axial length (AL) was 33% less at 0.27 mm (95% CI, 0.22‐0.32 mm) than at 0.40 mm (95% CI, 0.35‐0.45 mm) for the contact lens and spectacle lens groups, respectively. CONCLUSIONS. The 12-month data support the hypothesis that reducing peripheral hyperopia can alter central refractive development and reduce the rate of progress of myopia. (chictr.org number, chiCTR-TRC-00000029 or chiCTRTRC-00000032.) (Invest Ophthalmol Vis Sci. 2011;52: 9362‐9367) DOI:10.1167/iovs.11-7260 I n addition to the cost, inconvenience, and complications associated with traditional optical and surgical correction strategies, myopia is associated with ocular complications that can lead to permanent vision loss. Excessive axial elongation in high myopia increases the risk for cataract, glaucoma, chorioretinal degeneration, and idiopathic retinal detachment 1‐3

Reliable communication over channels with insertions, deletions, and substitutions

Abstract: A new block code is introduced which is capable of correcting multiple insertion, deletion, and substitution errors. The code consists of nonlinear inner codes, which we call "watermark"" codes, concatenated with low-density parity-check codes over nonbinary fields. The inner code allows probabilistic resynchronization and provides soft outputs for the outer decoder, which then completes decoding. We present codes of rate 0.7 and transmitted length 5000 bits that can correct 30 insertion/deletion errors per block. We also present codes of rate 3/14 and length 4600 bits that can correct 450 insertion/deletion errors per block.

The Ecophysiology of Foliar Anthocyanin

Abstract: The accumulation of foliar anthocyanins can be consistently attributed to a small range of contexts. Foliar anthocyanin accumulates in young, expanding foliage, in autumnal foliage of deciduous species, in response to nutrient deficiency or ultraviolet (UV) radiation exposure, and in association with damage or defense against browsing herbivores or pathogenic fungal infection. A common thread through these causative factors is low photosynthetic capacity of foliage with accumulated anthocyanin relative to leaves at different ontogenetic stages or unaffected by the environmental factor in question.