Designing a resource-efficient data structure for mobile data systems

Designing data structures for use in mobile devices requires attention on optimising data volumes with associated benefits for data transmission, storage space and battery use. For semi-structured data, tree summarisation techniques can be used to reduce the volume of structured elements while dictionary compression can efficiently deal with value-based predicates. This project seeks to investigate and evaluate an integration of the two approaches. The key strength of this technique is that both structural and value predicates could be resolved within one graph while further allowing for compression of the resulting data structure. As the current trend is towards the requirement for working with larger semi-structured data sets this work would allow for the utilisation of much larger data sets whilst reducing requirements on bandwidth and minimising the memory necessary both for the storage and querying of the data

Compressed materialised views of semi-structured data

Query performance issues over semi-structured data have led to the emergence of materialised XML views as a means of restricting the data structure processed by a query. However preserving the conventional representation of such views remains a significant limiting factor especially in the context of mobile devices where processing power, memory usage and bandwidth are significant factors. To explore the concept of a compressed materialised view, we extend our earlier work on structural XML compression to produce a combination of structural summarisation and data compression techniques. These techniques provide a basis for efficiently dealing with both structural queries and valuebased predicates. We evaluate the effectiveness of such a scheme, presenting results and performance measures that show advantages of using such structures

Extracting partition statistics from semistructured data

The effective grouping, or partitioning, of semistructured data is of fundamental importance when providing support for queries. Partitions allow items within the data set that share common structural properties to be identified efficiently. This allows queries that make use of these properties, such as branching path expressions, to be accelerated. Here, we evaluate the effectiveness of several partitioning techniques by establishing the number of partitions that each scheme can identify over a given data set. In particular, we explore the use of parameterised indexes, based upon the notion of forward and backward bisimilarity, as a means of partitioning semistructured data; demonstrating that even restricted instances of such indexes can be used to identify the majority of relevant partitions in the data

Wave Climate at Moffat Beach

The analysis of a series of wave recordings made at Moffat Beach, Queensland using an OSPOS wave recorder during 1963-1964 is described. This analysis included (i) the establishment of representative parameters for each wave recording; (ii) the determination of the frequency of occurrence of the representative parameters over the total recording period and (iii) the comparison of the recorded data with visual observations at Cape Moreton and the adjustment of the frequency curves to a longer more Queensland coast cannot be recommended.representative period of time.The results of the analysis provide confirmation of the\ua0applicability of the Rayleigh distribution to the short term wave\ua0height distribution within a given wave recording. On the other hand\ua0no definite conclusions are made concerning which theoretical\ua0representation of the long term wave height frequency of occurrence\ua0is to be preferred.The data analysed shows that at least four distinct types\ua0of wave conditions make up the overall wave climate in this area. The\ua0general wave height and period characteristics representative of these\ua0conditions together with seasonal variations are presented.The Moffat Beach wave data is compared with that obtained off\ua0the Gold Coast using Wave Rider buoys. Generally similar values of\ua0significant wave height are found but the wave periods are appreciably\ua0different. An analysis of possible explanations for this difference\ua0suggests that the filter effect due to pressure attenuation almost\ua0completely removes local wind generated seas from the OSPOS records.\ua0The question of a representative wave period for a given wave recording\ua0is considered and it is concluded that the use of the zero crossing\ua0period Tz\ua0for the analysis of unfiltered surface wave recordings of\ua0simultaneous sea and swell such as generally occurs off the southern\ua0Queensland coast cannot be recommended

Sharing large data collections between mobile peers

New directions in the provision of end-user computing experiences mean that we need to determine the best way to share data between small mobile computing devices. Partitioning large structures so that they can be shared efficiently provides a basis for data-intensive applications on such platforms. In conjunction with such an approach, dictionary-based compression techniques provide additional benefits and help to prolong battery life

Unanchored tri-NEDD8 inhibits PARP-1 to protect from oxidative stress-induced cell death

NEDD8 is a ubiquitin‐like protein that activates cullin‐RING E3 ubiquitin ligases (CRLs). Here, we identify a novel role for NEDD8 in regulating the activity of poly(ADP‐ribose) polymerase 1 (PARP‐1) in response to oxidative stress. We show that treatment of cells with H2O2 results in the accumulation of NEDD8 chains, likely by directly inhibiting the deneddylase NEDP1. One chain type, an unanchored NEDD8 trimer, specifically bound to the second zinc finger domain of PARP‐1 and attenuated its activation. In cells in which Nedp1 is deleted, large amounts of tri‐NEDD8 constitutively form, resulting in inhibition of PARP‐1 and protection from PARP‐1‐dependent cell death. Surprisingly, these NEDD8 trimers are additionally acetylated, as shown by mass spectrometry analysis, and their binding to PARP‐1 is reduced by the overexpression of histone de‐acetylases, which rescues PARP‐1 activation. Our data suggest that trimeric, acetylated NEDD8 attenuates PARP‐1 activation after oxidative stress, likely to delay the initiation of PARP‐1‐dependent cell death

Factors associated with uptake of services to prevent mother-to-child transmission of HIV in a community cohort in rural Tanzania.

OBJECTIVES: This study aimed to identify factors associated with access to HIV care and antiretroviral (ARV) drugs for prevention of mother-to-child transmission (PMTCT) of HIV among HIV-positive pregnant women in a community cohort in rural Tanzania (Kisesa). METHODS: Kisesa-resident women who tested HIV-positive during HIV serosurveillance and were pregnant (while HIV-positive) between 2005 and 2012 were eligible. Community cohort records were linked to PMTCT and HIV clinic data from four facilities (PMTCT programme implemented in 2009; referrals to city-based hospitals since 2005) to ascertain service use. Factors associated with access to HIV care and ARVs during pregnancy were analysed using logistic regression. RESULTS: Overall, 24% of women accessed HIV care and 12% accessed ARVs during pregnancy (n=756 pregnancies to 420 women); these proportions increased over time. In multivariate analyses for 2005-2012, being married, prior voluntary counselling and testing, increasing age, increasing year of pregnancy and increasing duration of infection were independently associated with access to care and ARVs. Residence in roadside areas was an independent predictor of access to care but not ARVs. There was no evidence of an interaction with time period. CONCLUSIONS: Access to PMTCT services was low in this rural setting but improved markedly over time. There were fairly few sociodemographic differentials although support for young women and those without partners may be needed. Further decentralisation of HIV services to more remote areas, promotion of voluntary counselling and testing and implementation of Option B+ are likely to improve uptake and may bring women into care and treatment sooner after infection

Risk factors for service use and trends in coverage of different HIV testing and counselling models in northwest Tanzania between 2003 and 2010.

OBJECTIVES: To investigate the relative effectiveness of different HIV testing and counselling (HTC) services in improving HIV diagnosis rates and increasing HTC coverage in African settings. METHODS: Patient records from three HTC services [community outreach HTC during cohort study rounds (CO-HTC), walk-in HTC at the local health centre (WI-HTC) and antenatal HIV testing (ANC-HTC)] were linked to records from a community cohort study using a probabilistic record linkage algorithm. Characteristics of linked users of each HTC service were compared to those of cohort participants who did not use the HTC service using logistic regression. Data from three cohort study rounds between 2003 and 2010 were used to assess trends in the proportion of persons testing at different service types. RESULTS: The adjusted odds ratios for HTC use among men with increasing numbers of sexual partners in the past year, and among HIV-positive men and women compared to HIV-negative men and women, were higher at WI-HTC than at CO-HTC and ANC-HTC. Among sero-survey participants, the largest numbers of HIV-positive men and women learned their status via CO-HTC. However, we are likely to have underestimated the numbers diagnosed at WI-HTC and ANC-HTC, due to low sensitivity of the probabilistic record linkage algorithm. CONCLUSIONS: Compared to CO-HTC or ANC-HTC, WI-HTC was most likely to attract HIV-positive men and women, and to attract men with greater numbers of sexual partners. Further research should aim to optimise probabilistic record linkage techniques, and to investigate which types of HTC services most effectively link HIV-positive people to treatment services relative to the total cost per diagnosis made