21,329 research outputs found
PrivLava: Synthesizing Relational Data with Foreign Keys under Differential Privacy
Answering database queries while preserving privacy is an important problem
that has attracted considerable research attention in recent years. A canonical
approach to this problem is to use synthetic data. That is, we replace the
input database R with a synthetic database R* that preserves the
characteristics of R, and use R* to answer queries. Existing solutions for
relational data synthesis, however, either fail to provide strong privacy
protection, or assume that R contains a single relation. In addition, it is
challenging to extend the existing single-relation solutions to the case of
multiple relations, because they are unable to model the complex correlations
induced by the foreign keys. Therefore, multi-relational data synthesis with
strong privacy guarantees is an open problem. In this paper, we address the
above open problem by proposing PrivLava, the first solution for synthesizing
relational data with foreign keys under differential privacy, a rigorous
privacy framework widely adopted in both academia and industry. The key idea of
PrivLava is to model the data distribution in R using graphical models, with
latent variables included to capture the inter-relational correlations caused
by foreign keys. We show that PrivLava supports arbitrary foreign key
references that form a directed acyclic graph, and is able to tackle the common
case when R contains a mixture of public and private relations. Extensive
experiments on census data sets and the TPC-H benchmark demonstrate that
PrivLava significantly outperforms its competitors in terms of the accuracy of
aggregate queries processed on the synthetic data.Comment: This is an extended version of a SIGMOD 2023 pape
Elite perceptions of the Victorian and Edwardian past in inter-war England
It is often argued by historians that members of the cultivated Elite after 1918 rejected the pre-war past. or at least subjected it to severe denigration. This thesis sets out to challenge such a view. Above all, it argues that inter-war critics of the Victorian and Edwardian past were unable to reject it even if that was what they felt inclined to do. This was because they were tied to those periods by the affective links of memory, family, and the continually unfolding consequences of the past in the present. Even the severest critics of the pre-war world, such as Lytton Strachey, were less frequently dismissive of history than ambivalent towards it. This ambivalence, it is argued, helped to keep the past alive and often to humanise it. The thesis also explores more positive estimation of Victorian and Edwardian history between the wars. It examines nostalgia for the past, as well as instances of continuity of practice and attitude. It explores the way in which inter-war society drew upon aspects of Victorian and Edwardian history both as illuminating parallels to contemporary affairs and to understand directly why the present was shaped as it was. Again, this testifies to the enduring power of the past after 1918. There are three parts to this thesis. Part One outlines the cultural context in which writers contemplated the Victorian and Edwardian past. Part Two explores some of the ways in which history was written about and used by inter-war society. Part Three examines the ways in which biographical depictions of eminent Victorians after 1918 encouraged emotional negotiation with the pas
Sponsorship image and value creation in E-sports
.E-sports games can drive the sports industry forward and sponsorship is the best way to engage consumers of this new sport. The purpose of this study is to examine the effect of sponsorship image and consumer participation in co-creation consumption activities on fansâ sponsorship response (represented by the variables interest, purchase intention and word of mouth) in e-sports. Four antecedent variables build sponsorship image (i.e., ubiquity of sport, sincerity of sponsor, attitude to sponsor and team identification). A quantitative approach is used for the purposes of this study. Some 445 questionnaires were filled in by fans who watch e-sports in Spain; these are analyzed using partial least squares structural equation modeling (PLS-SEM). The outcomes show that sponsor antecedents are crucial factors if a sponsor wants to change their sponsorship image and influence sponsorship response, and that it is also possible to use participation to improve responsesS
Embodying entrepreneurship: everyday practices, processes and routines in a technology incubator
The growing interest in the processes and practices of entrepreneurship has
been dominated by a consideration of temporality. Through a thirty-six-month
ethnography of a technology incubator, this thesis contributes to extant
understanding by exploring the effect of space. The first paper explores how
class structures from the surrounding city have appropriated entrepreneurship
within the incubator. The second paper adopts a more explicitly spatial analysis
to reveal how the use of space influences a common understanding of
entrepreneurship. The final paper looks more closely at the entrepreneurs within
the incubator and how they use visual symbols to develop their identity. Taken
together, the three papers reject the notion of entrepreneurship as a primarily
economic endeavour as articulated through commonly understood language and
propose entrepreneuring as an enigmatic attractor that is accessed through the
ambiguity of the non-verbal to develop the ânewâ. The thesis therefore contributes
to the understanding of entrepreneurship and proposes a distinct role for the non-verbal in that understanding
Underwater optical wireless communications in turbulent conditions: from simulation to experimentation
Underwater optical wireless communication (UOWC) is a technology that aims to apply high speed optical wireless communication (OWC) techniques to the underwater channel. UOWC has the potential to provide high speed links over relatively short distances as part of a hybrid underwater network, along with radio frequency (RF) and underwater acoustic communications (UAC) technologies. However, there are some difficulties involved in developing a reliable UOWC link, namely, the complexity of the channel. The main focus throughout this thesis is to develop a greater understanding of the effects of the UOWC channel, especially underwater turbulence. This understanding is developed from basic theory through to simulation and experimental studies in order to gain a holistic understanding of turbulence in the UOWC channel.
This thesis first presents a method of modelling optical underwater turbulence through simulation that allows it to be examined in conjunction with absorption and scattering. In a stationary channel, this turbulence induced scattering is shown to cause and increase both spatial and temporal spreading at the receiver plane. It is also demonstrated using the technique presented that the relative impact of turbulence on a received signal is lower in a highly scattering channel, showing an in-built resilience of these channels. Received intensity distributions are presented confirming that fluctuations in received power from this method follow the commonly used Log-Normal fading model. The impact of turbulence - as measured using this new modelling framework - on link performance, in terms of maximum achievable data rate and bit error rate is equally investigated.
Following that, experimental studies comparing both the relative impact of turbulence induced scattering on coherent and non-coherent light propagating through water and the relative impact of turbulence in different water conditions are presented. It is shown that the scintillation index increases with increasing temperature inhomogeneity in the underwater channel. These results indicate that a light beam from a non-coherent source has a greater resilience to temperature inhomogeneity induced turbulence effect in an underwater channel. These results will help researchers in simulating realistic channel conditions when modelling a light emitting diode (LED) based intensity modulation with direct detection (IM/DD) UOWC link.
Finally, a comparison of different modulation schemes in still and turbulent water conditions is presented. Using an underwater channel emulator, it is shown that pulse position modulation (PPM) and subcarrier intensity modulation (SIM) have an inherent resilience to turbulence induced fading with SIM achieving higher data rates under all conditions. The signal processing technique termed pair-wise coding (PWC) is applied to SIM in underwater optical wireless communications for the first time. The performance of PWC is compared with the, state-of-the-art, bit and power loading optimisation algorithm. Using PWC, a maximum data rate of 5.2 Gbps is achieved in still water conditions
RNA pull-down-confocal nanoscanning (RP-CONA), a novel method for studying RNA/protein interactions in cell extracts that detected potential drugs for Parkinsonâs disease targeting RNA/HuR complexes
MicroRNAs (miRNAs, miRs) are a class of small non-coding RNAs that regulate gene expression through specific base-pair targeting. The functional mature miRNAs usually undergo a two-step cleavage from primary miRNAs (pri-miRs), then precursor miRNAs (pre-miRs). The biogenesis of miRNAs is tightly controlled by different RNA-binding proteins (RBPs). The dysregulation of miRNAs is closely related to a plethora of diseases. Targeting miRNA biogenesis is becoming a promising therapeutic strategy.
HuR and MSI2 are both RBPs. MiR-7 is post-transcriptionally inhibited by the HuR/MSI2 complex, through a direct interaction between HuR and the conserved terminal loop (CTL) of pri-miR-7-1. Small molecules dissociating pri-miR-7/HuR interaction may induce miR-7 production. Importantly, the miR-7 levels are negatively correlated with Parkinsonâs disease (PD).
PD is a common, incurable neurodegenerative disease causing serious motor deficits. A hallmark of PD is the presence of Lewy bodies in the human brain, which are inclusion bodies mainly composed of an aberrantly aggregated protein named α-synuclein (α-syn). Decreasing α-syn levels or preventing α-syn aggregation are under investigation as PD treatments. Notably, α-syn is negatively regulated by several miRNAs, including miR-7, miR-153, miR-133b and others. One hypothesis is that elevating these miRNA levels can inhibit α-syn expression and ameliorate PD pathologies.
In this project, we identified miR-7 as the most effective α-syn inhibitor, among the miRNAs that are downregulated in PD, and with α-syn targeting potentials. We also observed potential post-transcriptional inhibition on miR-153 biogenesis in neuroblastoma, which may help to uncover novel therapeutic targets towards PD.
To identify miR-7 inducers that benefit PD treatment by repressing α-syn expression, we developed a novel technique RNA Pull-down Confocal Nanoscaning (RP-CONA) to monitor the binding events between pri-miR-7 and HuR. By attaching FITC-pri-miR-7-1-CTL-biotin to streptavidin-coated agarose beads and incubating them in human cultured cell lysates containing overexpressed mCherry-HuR, the bound RNA and protein can be visualised as quantifiable fluorescent rings in corresponding channels in a confocal high-content image system. A pri-miR-7/HuR inhibitor can decrease the relative mCherry/FITC intensity ratio in RP-CONA. With this technique, we performed several small-scale screenings and identified that a bioflavonoid, quercetin can largely dissociate the pri-miR-7/HuR interaction. Further studies proved that quercetin was an effective miR-7 inducer as well as α-syn inhibitor in HeLa cells.
To understand the mechanism of quercetin mediated α-syn inhibition, we tested the effects of quercetin treatment with miR-7-1 and HuR knockout HeLa cells. We found that HuR was essential in this pathway, while miR-7 hardly contributed to the α-syn inhibition. HuR can directly bind an AU-rich element (ARE) at the 3â untranslated region (3â-UTR) of α-syn mRNA and promote translation. We believe quercetin mainly disrupts the ARE/HuR interaction and disables the HuR-induced α-syn expression.
In conclusion, we developed and optimised RP-CONA, an on-bead, lysate-based technique detecting RNA/protein interactions, as well as identifying RNA/protein modulators. With RP-CONA, we found quercetin inducing miR-7 biogenesis, and inhibiting α-syn expression. With these beneficial effects, quercetin has great potential to be applied in the clinic of PD treatment. Finally, RP-CONA can be used in many other RNA/protein interactions studies
Immunoinformatics and Computer-Aided Drug Design as New Approaches against Emerging and Re-Emerging Infectious Diseases
Infectious diseases are initiated by small pathogenic living germs that are transferred from person to person by direct or indirect contact. Recently, different newly emerging and reemerging infectious viral diseases have become greater threats to human health and global stability. Investigators can anticipate epidemics through the advent of numerous mathematical tools that can predict specific pathogens and identify potential targets for vaccine and drug design and will help to fight against these challenges. Currently, computational approaches that include mathematical and essential tools have unfolded the way for a better understanding of newly originated emerging and re-emerging infectious disease, pathogenesis, diagnosis, and treatment option of specific diseases more easily, where immunoinformatics plays a crucial role in the discovery of novel peptides and vaccine candidates against the different viruses within a short time. Computational approaches include immunoinformatics, and computer-aided drug design (CADD)-based model trained biomolecules that offered reasonable and quick implementation approaches for the modern discovery of effective viral therapies. The essence of this review is to give insight into the multiple approaches not only for the detection of infectious diseases but also profound how people can pick appropriate models for the detection of viral therapeutics through computational approaches
The biology and general ecology of the Koaro (Galaxias brevipinnis) in some tributary streams of Lake Taupo
The ecology and general biology of Galaxias brevipinnis were studied in three tributary streams of Lake Taupo between May 1988 and April 1989. Adult koaro were found in relatively high densities in the Waipehi and Omori streams but in low densities in the larger Waiotaka stream. The results of population estimation studies suggest that the distribution and abundance of koaro is negatively correlated with that of trout. There was a general decline in the population density of stream-resident koaro in the winter months. Juvenile koaro were found to migrate into the tributaries from August to December, with migrations being at a peak in October and November.
Population length-frequency distributions and otoliths used to age koaro indicated that there were up to 5 age classes. Growth was allometric and was adequately described by the von Bertalanffy equation after the first year of life. Koaro were found to be in best condition in the Spring and lowest in Winter.
Spawning appeared to occur from December through to April peaking in late Summer to early in the Waipehi Stream was Autumn. The mean fecundity of koaro approximately 5500. A sex-ratio of approximately 1:1 (males: females) were found in the koaro populations in the Omori and Waipehi streams, but during spawning there were always more ripe males than gravid females.
There was considerable overlap in the diets of both koaro and juvenile rainbow trout in the Waipehi and Omori streams, with invertebrates being consumed according to their relative abundance in the benthos. Ephemeroptera larvae were numerically the most important food item in the diet of both species. However, by weight, fish (juvenile koaro) were the most important food · item in the diet of koaro and rainbow trout in the Waipehi stream. In the Omori stream in Winter, trout eggs were the most important food item in terms of weight. Terrestrial prey was found to be of relatively minor importance in the diets of koaro and rainbow trout in the Waipehi and Omori streams
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