8 research outputs found
Visualization of a data leak : how can visualization assist to determine the scope of an attack?
The potential impact that data leakage can have on a country, both on a national level as well as on an individual level, can be wide reaching and potentially catastrophic. In January 2013, several South African companies became the target of a hack attack, resulting in the breach of security measures and the leaking of a claimed 700000 records. The affected companies are spread across a number of domains, thus making the leak a very wide impact area. The aim of this paper is to analyze the data released from the South African breach and to visualize the extent of the loss by the companies affected. The value of this work lies in its connection to and interpretation of related South African legislation. The data extracted during the analysis is primarily personally identifiable information, such as defined by the Electronic Communications and Transactions Act of 2002 and the Protection of Personal Information Bill of 2009
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The carbon and nitrogen isotopic composition of ureilites: Implications for their genesis
Fourteen ureilites were analyzed for stable C isotopic composition using stepped combustion. The
δ
13
C values over the temperature range 500 to 1000°C are fairly constant for any particular meteorite although there are differences between samples. The similarity in combustion temperatures of pure diamond (600–1000δC) and pure graphite (600–800°C) makes it difficult to ascertain the relative proportions of either component within each sample. However, the constant
δ
13
C values observed over the range 500 to 1000°C strongly suggests that ureilite diamond and graphite have the same isotopic composition. This would seem to confirm that the diamond in ureilites formed from the graphite during a process, presumably an impact event, which did not fractionate C isotopes.
There is a variation in C isotopic composition of graphite/diamond intergrowths among ureilites, which is not continuous—the samples fall into two groups, with
δ
13
C values clustered around −10%. and −2%. PDB. These groups are also distinguishable on the basis of the Fe content of their olivines, which may reflect the existence of more than one ureilite parent body. The brecciated ureilite North Haig has a
δ
13
C value of −6.5%. and it is thus possible that this sample contains components from mixed parent materials.
Nitrogen abundance and stable isotope measurements were made on five samples using stepped combustion analysis. Nitrogen concentrations range from 25 to 150 ppm and
C
N
ratios are substantially less than for carbonaceous chondrites. Variation in N isotopic composition is wide and there is evidence of different ratios in diamond/graphite, silicate and metal
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The carbon and oxygen isotopic composition of meteoritic carbonates
The
13C
12C
and
18O
16O
isotopic ratios of carbonates from carbonaceous and ordinary chondrites have been measured on CO
2 released by the action of H
3PO
4 on whole-rock samples. Carbonates from CI, CM and CR carbonaceous chondrites exhibit a range in
δ
18
O of
ca. 15%. (+20.5%. to +35.1%. relative to SMOW). Limited data from CO
2-water equilibration experiments suggest that meteoritic carbonates do not possess grossly anomalous
17O isotopic compositions; therefore, they are truly enriched in
13C, with
δ
13
C between +23.7%. and +80.7%. relative to PDB. Large internal variations in
δ
13
C and
δ
18
O were found in individual meteorites and suggest that two or more isotopically distinct carbonates of different origin may be present. The abundance,
δ
13
C and
δ
18
O of carbonate in CM2 chondrites may be related to the extent of aqueous alteration of the meteorites. Carbonates in CI and CR chondrites have a median
δ
13
C ca. +50 to +60%., whereas
δ
13
C of CM meteorites lie in the range +40 to +50%., although exceptions exist in both sets of samples. CV3 and CO3 carbonaceous chondrites and unequilibrated ordinary chondrites release small amounts of CO
2 on acid treatment, which might be from carbonate dissolution, but which is not enriched in
13C, exhibiting
δ
13
C values
ca. 0 ± 10%. The exception to this is Bishunpur, with
δ
13
C ca. −23.5%.. The difference in
δ
13
C of the CI, CM and CR
vs. CV, CO and ordinary chondrite carbonates may be a result of the progressive enrichment in
13C of percolating fluids, brought about by increasing solubilization of “exotic”
13C-enriched grains
Variation of the gene coding for DARPP-32 (PPP1R1B) and brain connectivity during associative emotional learning
Associative emotional learning, which is important for the social emotional functioning of individuals and is often impaired in psychiatric illnesses, is in part mediated by dopamine and glutamate pathways in the brain. The protein DARPP-32 is involved in the regulation of dopaminergic and glutaminergic signaling. Consequently, it has been suggested that the haplotypic variants of the gene PPP1R1B that encodes DARPP-32 are associated with working memory and emotion processing. We hypothesized that PPP1R1B should have a significant influence on the network of brain regions involved in associative emotional learning that are rich in DARPP-32, namely the striatum, prefrontal cortex (comprising the medial frontal gyrus and inferior frontal gyrus (IFG)), amygdala and parahippocampal gyrus (PHG). Dynamic causal models were applied to functional MRI data to investigate how brain connectivity during an associative emotional learning task is affected by different single-nucleotide polymorphisms (SNPs) of PPP1R1B: rs879606, rs907094 and rs3764352. Compared to heterozygotes, homozygotes with GTA alleles displayed increased intrinsic connectivity between the IFG and PHG, as well as increased excitability of the PHG for negative emotional stimuli. We have also elucidated the directionality of these genetic influences. Our data suggest that homozygotes with GTA alleles involve stronger functional connections between brain areas in order to maintain activation of these regions. Homozygotes might engage a greater degree of motivational learning and integration of information to perform the emotional learning task correctly. We conclude that PPP1R1B is associated with the neural network involved in associative emotional learning
Diversidade fenotípica e patogênica de Colletotrichum, agente causal da antracnose em mangueira, e identificação de espécie
O presente trabalho teve como objetivo estudar a diversidade fenotípica e patogênica de 40 isolados de Colletotrichum obtidos de mangueira no Nordeste do Brasil e identificar diferentes espécies desse fitopatógeno, agente causal de antracnose, através da análise da seqüência da região ITS do rDNA. Quanto à caracterização morfológica e cultural, as colônias dos isolados apresentaram diversidade em relação à cor e aspecto, sendo mais comum à cor branco-cinza, característica de Colletotrichum gloeosporioides. Não foram observadas variações expressivas na morfologia dos 40 isolados. Os conídios apresentaram-se, predominantemente, hialinos e unicelulares, com formato variando de bastonete para cilíndrico. Todos os isolados produziram apressórios variados em formato e quantidade e apenas 10 isolados apresentaram setas. Para efeito do crescimento micelial e taxa de crescimento foi possível classificar os isolados em sete grupos. Vinte e dois isolados exibiram taxa de crescimento >10mm/dia, considerada típica da espécie C. gloeosporioides. Os isolados foram patogênicos em folhas destacadas de mangueira, induzindo sintomas de antracnose, na forma de manchas escuras levemente deprimidas, e apresentando variações quanto à agressividade. Na identificação específica, baseada na análise da seqüência ITS do DNA ribossomal, 36 isolados amplificaram com o oligonucleotídeos CgInt, específico para C. gloeosporioides e o ITS4, Os isolados CM1, CM4, CM5 e CM10, não amplificaram produtos para nenhum dos oligonucleotídeos específicos, sendo identificados como Colletotrichum spp. Os resultados desse trabalho demonstraram que isolados de Colletotrichum, obtidos de mangueira, apresentam ampla variabilidade morfofisiológica e patogênica. E que, possivelmente, existe mais de uma espécie de Colletotrichum que causa antracnose em mangueira no Nordeste do Brasil