12,274 research outputs found
Minority ethnic groups in British labour market (1972-2005): Exploring patterns, trends and processes of minority ethnic disadvantages
On the Security of Millimeter Wave Vehicular Communication Systems using Random Antenna Subsets
Millimeter wave (mmWave) vehicular communica tion systems have the potential
to improve traffic efficiency and safety. Lack of secure communication links,
however, may lead to a formidable set of abuses and attacks. To secure
communication links, a physical layer precoding technique for mmWave vehicular
communication systems is proposed in this paper. The proposed technique
exploits the large dimensional antenna arrays available at mmWave systems to
produce direction dependent transmission. This results in coherent transmission
to the legitimate receiver and artificial noise that jams eavesdroppers with
sensitive receivers. Theoretical and numerical results demonstrate the validity
and effectiveness of the proposed technique and show that the proposed
technique provides high secrecy throughput when compared to conventional array
and switched array transmission techniques
Systematic review of carbapenem-resistant Enterobacteriaceae causing neonatal sepsis in China.
BACKGROUND: Carbapenems are β-lactam antibiotics which are used to treat severe infections caused by multidrug resistant Enterobacteriacea. The recent emergence and rapid spread of Enterobacteriaceae resistant to carbapenems is a global concern. We undertook a systematic review of the antibiotic susceptibility and genotypic characteristics of carbapenem-resistant Enterobacteriaceae in Chinese neonates. METHODS: Systematic literature reviews were conducted (PubMed/Medline, Embase, Wanfang medical online databases, China National Knowledge Infrastructure (CNKI) database) regarding sepsis caused by carbapenem-resistant Enterobacteriaceae in Chinese neonates aged 0-30 days. RESULTS: 17 studies were identified. Eleven patients in the six studies reported the source of infection. Ten patients (10/11, 90.9%) were hospital-acquired infections. Genotypic data were available for 21 isolates in 11 studies (20 K. pneumoniae, 1 E. coli). NDM-1 was the most frequently reported carbapenem-resistant genotype (81.0%, 17/21). Carbapenem-resistant Klebsiella pneumoniae and Escherichia coli were resistant to many antibiotic classes with the exception of colistin and fosfomycin. Sequence type 105 (ST105) was the most commonly reported K. pneumoniae ST type (30.8%; 4/13), which was from the same hospital in Western China. ST17 and ST20 were the second and third most common K. pneumoniae ST type, 23.1% (3/13) and 15.4% (2/13) respectively. The three strains of ST17 are all from the same hospital in central China. The two strains of ST20, although not from the same hospital, belong to the eastern part of China. CONCLUSIONS: Klebsiella pneumoniae with the NDM-1 genotype was the leading cause of neonatal carbapenem resistant sepsis in China. Hospital acquired infection is the main source of carbapenem resistant sepsis. There is currently no licenced antibiotic regimen available to treat such an infection in China. Improved surveillance, controlling nosocomial infection and the rational use of antibiotics are the key factors to prevent and reduce its spread
Inequalities in education, employment and earnings among equality groups: A research review and analysis of trends over time
How Many and What Types of SPARQL Queries can be Answered through Zero-Knowledge Link Traversal?
The current de-facto way to query the Web of Data is through the SPARQL
protocol, where a client sends queries to a server through a SPARQL endpoint.
Contrary to an HTTP server, providing and maintaining a robust and reliable
endpoint requires a significant effort that not all publishers are willing or
able to make. An alternative query evaluation method is through link traversal,
where a query is answered by dereferencing online web resources (URIs) at real
time. While several approaches for such a lookup-based query evaluation method
have been proposed, there exists no analysis of the types (patterns) of queries
that can be directly answered on the live Web, without accessing local or
remote endpoints and without a-priori knowledge of available data sources. In
this paper, we first provide a method for checking if a SPARQL query (to be
evaluated on a SPARQL endpoint) can be answered through zero-knowledge link
traversal (without accessing the endpoint), and analyse a large corpus of real
SPARQL query logs for finding the frequency and distribution of answerable and
non-answerable query patterns. Subsequently, we provide an algorithm for
transforming answerable queries to SPARQL-LD queries that bypass the endpoints.
We report experimental results about the efficiency of the transformed queries
and discuss the benefits and the limitations of this query evaluation method.Comment: Preprint of paper accepted for publication in the 34th ACM/SIGAPP
Symposium On Applied Computing (SAC 2019
Haemophilus influenzae type b reemergence after combination immunization
An increase in Haemophilus influenzae type b (Hib) in
British children has been linked to the widespread use of a
diphtheria/tetanus/acellular pertussis combination vaccine
(DTaP-Hib). We measured anti-polyribosyl-ribitol phos-
phate antibody concentration and avidity before and after a
Hib booster in 176 children 2–4 years of age who had
received 3 doses of DTP-Hib (either DT whole cell pertus-
sis-Hib or DTaP-Hib) combination vaccine in infancy. We
also measured pharyngeal carriage of Hib. Antibody con-
centrations before and avidity indices after vaccination
were low (geometric mean concentration 0.46μg/mL, 95%
confidence interval [CI] 0.36–0.58; geometric mean avidity
index 0.16, 95% CI 0.14–0.18) and inversely related to the
number of previous doses of DTaP-Hib (p = 0.02 and
p<0.001, respectively). Hib was found in 2.1% (95% CI
0.7%–6.0%) of study participants. Our data support an
association between DTaP-Hib vaccine combinations and
clinical Hib disease through an effect on antibody concen-
tration and avidit
Secure Communications in Millimeter Wave Ad Hoc Networks
Wireless networks with directional antennas, like
millimeter wave (mmWave) networks, have enhanced security.
For a large-scale mmWave ad hoc network in which eavesdroppers are randomly located, however, eavesdroppers can still intercept the confidential messages, since they may reside in the signal beam. This paper explores the potential of physical layer security in mmWave ad hoc networks. Specifically, we characterize the impact of mmWave channel characteristics, random blockages, and antenna gains on the secrecy performance. For the special case of uniform linear array (ULA), a tractable approach is proposed to evaluate the average achievable secrecy rate. We also characterize the impact of artificial noise in such networks. Our results reveal that in the low transmit power regime, the use of low mmWave frequency achieves better secrecy performance, and when increasing transmit power, a transition from low mmWave frequency to high mmWave frequency is demanded for obtaining a higher secrecy rate. More antennas at the transmitting nodes are needed to decrease the antenna gain obtained by the eavesdroppers when using ULA. Eavesdroppers can intercept more information by using a wide beam pattern. Furthermore, the use of artificial noise may be ineffective forenhancing the secrecy rate
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