25 research outputs found
Bimetallic copper palladium nanorods: plasmonic properties and palladium content effects
Cu is an inexpensive alternative plasmonic metal with optical behaviour comparable to Au but with much poorer environmental stability. Alloying with a more stable metal can improve stability and add functionality, with potential effects on the plasmonic properties. Here we investigate the plasmonic behaviour of Cu nanorods and Cu–CuPd nanorods containing up to 46 mass percent Pd. Monochromated scanning transmission electron microscopy electron energy-loss spectroscopy first reveals the strong length dependence of multiple plasmonic modes in Cu nanorods, where the plasmon peaks redshift and narrow with increasing length. Next, we observe an increased damping (and increased linewidth) with increasing Pd content, accompanied by minimal frequency shift. These results are corroborated by and expanded upon with numerical simulations using the electron-driven discrete dipole approximation. This study indicates that adding Pd to nanostructures of Cu is a promising method to expand the scope of their plasmonic applications
On the Security of HB# against a Man-in-the-Middle Attack
At EuroCrypt ’08, Gilbert, Robshaw and Seurin proposed HB# to improve on HB+ in terms of transmission cost and security against man-in-the-middle attacks. Although the security of HB# is formally proven against a certain class of man- in-the-middle adversaries, it is only conjectured for the general case. In this paper, we present a general man-in-the-middle attack against HB# and Random-HB#, which can also be applied to all anterior HB-like protocols, that recovers the shared secret in 225 or 220 authentication rounds for HB# and 234 or 228 for Random-HB#, depending on the parameter set. We further show that the asymptotic complexity of our attack is polynomial under some conditions on the parameter set which are met on one of those proposed in [8]
No evidence that protein truncating variants in BRIP1 are associated with breast cancer risk: implications for gene panel testing.
BACKGROUND: BRCA1 interacting protein C-terminal helicase 1 (BRIP1) is one of the Fanconi Anaemia Complementation (FANC) group family of DNA repair proteins. Biallelic mutations in BRIP1 are responsible for FANC group J, and previous studies have also suggested that rare protein truncating variants in BRIP1 are associated with an increased risk of breast cancer. These studies have led to inclusion of BRIP1 on targeted sequencing panels for breast cancer risk prediction. METHODS: We evaluated a truncating variant, p.Arg798Ter (rs137852986), and 10 missense variants of BRIP1, in 48 144 cases and 43 607 controls of European origin, drawn from 41 studies participating in the Breast Cancer Association Consortium (BCAC). Additionally, we sequenced the coding regions of BRIP1 in 13 213 cases and 5242 controls from the UK, 1313 cases and 1123 controls from three population-based studies as part of the Breast Cancer Family Registry, and 1853 familial cases and 2001 controls from Australia. RESULTS: The rare truncating allele of rs137852986 was observed in 23 cases and 18 controls in Europeans in BCAC (OR 1.09, 95% CI 0.58 to 2.03, p=0.79). Truncating variants were found in the sequencing studies in 34 cases (0.21%) and 19 controls (0.23%) (combined OR 0.90, 95% CI 0.48 to 1.70, p=0.75). CONCLUSIONS: These results suggest that truncating variants in BRIP1, and in particular p.Arg798Ter, are not associated with a substantial increase in breast cancer risk. Such observations have important implications for the reporting of results from breast cancer screening panels.The COGS project is funded through a European Commission's Seventh Framework Programme grant
(agreement number 223175 - HEALTH-F2-2009-223175). BCAC is funded by Cancer Research UK
[C1287/A10118, C1287/A12014] and by the European Community´s Seventh Framework Programme under
grant agreement number 223175 (grant number HEALTH-F2-2009-223175) (COGS). Funding for the iCOGS
infrastructure came from: the European Community's Seventh Framework Programme under grant agreement
n° 223175 (HEALTH-F2-2009-223175) (COGS), Cancer Research UK (C1287/A10118, C1287/A 10710,
C12292/A11174, C1281/A12014, C5047/A8384, C5047/A15007, C5047/A10692, C8197/A16565), the
National Institutes of Health (CA128978) and Post-Cancer GWAS initiative (1U19 CA148537, 1U19
16
CA148065 and 1U19 CA148112 - the GAME-ON initiative), the Department of Defense (W81XWH-10-1-
0341), the Canadian Institutes of Health Research (CIHR) for the CIHR Team in Familial Risks of Breast
Cancer, Komen Foundation for the Cure, the Breast Cancer Research Foundation, and the Ovarian Cancer
Research Fund. This study made use of data generated by the Wellcome Trust Case Control consortium.
Funding for the project was provided by the Wellcome Trust under award 076113. The results published here
are in part based upon data generated by The Cancer Genome Atlas Project established by the National Cancer
Institute and National Human Genome Research Institute.This is the author accepted manuscript. The final version is available from BMJ Group at http://dx.doi.org/10.1136/jmedgenet-2015-103529
Padrão Nictemeral do pH Ruminal e Comportamento Alimentar de Cabras Leiteiras Alimentadas com Dietas Contendo Diferentes Relações Volumoso: Concentrado Nictemeral Pattern of Ruminal pH and Feeding Behavior of Dairy Goats Fed Diets with Different Roughage to Concentrate Ratio
Os objetivos do presente estudo foram a caracterização do padrão nictemeral do pH ruminal e a avaliação do comportamento alimentar de cabras leiteiras alimentadas com dietas compostas por diferentes relações volumoso:concentrado. Foram utilizadas cinco cabras, com peso médio de 58 kg, não-lactantes, não-gestantes, fistuladas no rúmen, em cinco períodos experimentais. Cada animal foi observado em cada um dos cinco tratamentos, que consistiram das relações volumoso:concentrado de 100:0, 80:20, 60:40, 40:60 e 20:80, em um delineamento em quadrado latino 5×5. As dietas foram fornecidas a cada 6 horas, buscando amenizar a variação dos níveis de pH ruminal, durante o período de 24 horas, para todos os tratamentos. Após a adaptação dos animais às dietas experimentais, estes foram observados por um período de 48 horas, no qual foi mensurado o pH ruminal a cada hora, bem como em outro período de mesma duração, em que se observou o comportamento a cada 10 minutos. Foi constatado que o nível de concentrado crescente resultou em decréscimo sobre o pH, cujos valores decresceram mais drasticamente em níveis acima de 60%. Observou-se também o efeito de tratamento sobre tempo de alimentação, ruminação e ócio. O tempo de alimentação foi maior para as dietas contendo valores acima de 60% de volumoso. A dieta contendo 100% de volumoso apresentou maior tempo de ruminação e menor ócio, seguida das dietas contendo 80 e 60% de volumoso, enquanto aquelas contendo 40 e 20% apresentaram menor tempo de ruminação e maior ócio.<br>The objectives of the present study were to characterize nictemeral pattern of ruminal pH and feed behavior of dairy goats fed diets presenting different ratios of roughage:concentrate. Five non pregnant non lactating goats, ruminally cannulated, and averaging 58 kg were used during the five experimental periods. A 5x5 Latin square was used to evaluate five treatments consisted of roughage to concentrate ratio of 100:0, 80:20, 60:40, 40:60 e 20:80. Diets were fed every 6h in order to reduce ruminal pH variation during the 24h period. After adaptation to experimental diets, a 48h period was given to measure ruminal pH hourly for 24h, to be used as a covariate, following a study of feeding behavior where measurement was taken at every 10 minutes for the remaining 24h period. It was observed that increasing level of concentrate resulted in reduction of pH, especially when concentrate accounted for more than 60%. Treatment effect was also observed on time spent eating, ruminating and idling. Time spent eating was greater as percentage of roughage in the diet increased, especially over 60%. Roughage content of 100% presented the highest value of rumination time and the lowest value for idle, following diets containing 80 e 60% respectively. There were no difference between diets containing 40 e 20% roughage, which presented the lowest value for rumination and the highest for idle time
Parallel and concurrent security of the HB and HB+ protocols
Abstract. Juels and Weis (building on prior work of Hopper and Blum) propose and analyze two shared-key authentication protocols — HB and HB + — whose extremely low computational cost makes them attractive for low-cost devices such as radio-frequency identification (RFID) tags. Security of these protocols is based on the conjectured hardness of the “learning parity with noise ” (LPN) problem: the HB protocol is proven secure against a passive (eavesdropping) adversary, while the HB + protocol is proven secure against active attacks. Juels and Weis prove security of these protocols only for the case of sequential executions, and explicitly leave open the question of whether security holds also in the case of parallel or concurrent executions. In addition to guaranteeing security against a stronger class of adversaries, a positive answer to this question would allow the HB + protocol to be parallelized, thereby substantially reducing its round complexity. Adapting a recent result by Regev, we answer the aforementioned question in the affirmative and prove security of the HB and HB + protocols under parallel/concurrent executions. We also give what we believe to be substantially simpler security proofs for these protocols which are more complete in that they explicitly address the dependence of the soundness error on the number of iterations.
Solving LPN Using Covering Codes
We present a new algorithm for solving the LPN problem. The algorithm has a similar form as some previous methods, but includes a new key step that makes use of approximations of random words to a nearest codeword in a linear code. It outperforms previous methods for many parameter choices. In particular, we can now solve instances suggested for 80-bit security in cryptographic schemes like HB variants, LPN-C and Lapin, in less than 2(80) operations