An evaluation of completeness of tuberculosis notification in the United Kingdom

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Abstract
Background: There has been a resurgence of tuberculosis worldwide, mainly in developing
countries but also affecting the United Kingdom (UK), and other Western countries. The control
of tuberculosis is dependent on early identification of cases and timely notification to public health
departments to ensure appropriate treatment of cases and screening of contacts. Tuberculosis is
compulsorily notifiable in the UK, and the doctor making or suspecting the diagnosis is legally
responsible for notification. There is evidence of under-reporting of tuberculosis. This has
implications for the control of tuberculosis as a disproportionate number of people who become
infected are the most vulnerable in society, and are less likely to be identified and notified to the
public health system. These include the poor, the homeless, refugees and ethnic minorities.
Method: This study was a critical literature review on completeness of tuberculosis notification
within the UK National Health Service (NHS) context. The review also identified data sources
associated with reporting completeness and assessed whether studies corrected for undercount
using capture-recapture (CR) methodology. Studies were included if they assessed completeness
of tuberculosis notification quantitatively. The outcome measure used was notification
completeness expressed between 0% and 100% of a defined denominator, or in numbers not
notified where the denominator was unknown.
Results: Seven studies that met the inclusion and exclusion criteria were identified through
electronic and manual search of published and unpublished literature. One study used CR
methodology. Analysis of the seven studies showed that undernotification varied from 7% to 27%
in studies that had a denominator; and 38%–49% extra cases were identified in studies which
examined specific data sources like pathology reports or prescriptions for anti-tuberculosis drugs.
Cases notified were more likely to have positive microbiology than cases not notified which were
more likely to have positive histopathology or be surgical in-patients. Collation of prescription data
of two or more anti-tuberculosis drugs increases case ascertainment of tuberculosis.
Conclusion: The reporting of tuberculosis is incomplete in the UK, although notification is a
statutory requirement. Undernotification leads to an underestimation of the disease burden and
hinders implementation of appropriate prevention and control strategies. The notification systemneeds to be strengthened to include education and training of all sub-specialities involved in
diagnosis and treatment of tuberculosis

دانلود مقاله Performance Evaluation of Network Coding in IEEE 802.11 Wireless Ad Hoc Networks - انتشار 2014

اختصاصی از فی توو دانلود مقاله Performance Evaluation of Network Coding in IEEE 802.11 Wireless Ad Hoc Networks - انتشار 2014 دانلود با لینک مستقیم و پر سرعت .

Ad Hoc Networks

Volume 16, May 2014, Pages 131–141

Kyu-Hwan Lee, Sunghyun Cho, Jae-Hyun Kim

Abstract
We evaluate the practical network coding (NC) gain in a wireless ad hoc networks.
First, we introduce how network coding can be applied to IEEE 802.11
ad hoc networks. Next, we find obstructive factors by which the NC gain
may decrease as compared with the theoretical NC gain. Finally, through
the performance evaluation, we analyze why a performance difference occurs
between practical and theoretical NC gains owing to the suggested obstructive
factors. According to the simulated results, even though there is some
overhead caused by the characteristics of the media access control (MAC)
protocol and control signals to apply NC to wireless ad hoc networks, the
practical NC gain is almost the same as the theoretical gain in an ideal environment
for NC. However, in the NC system with the hidden node problem,
the NC gain decreases because of packet collision. In the NC system using
a promiscuous mode where packet overhearing is possible, nodes consume
more power than the conventional system because of overhearing packets.
For instance, when the number of overhearing nodes not related to NC is set
to 15, the power reduction rate is −38.04%. Furthermore, under the network
conditions inappropriate for NC, such as asymmetric flows and scarce coding
structures, the NC gain can be considerably reduced. For example, in
5x5 and 7x7 grid topology networks, the load reduction rate by NC are only
4.12% and 7.01%, respectively. Therefore, research to solve the suggested
obstructive factors is necessary to achieve sufficient NC gain in a practicalwireless network such as an IEEE 802.11 ad hoc networks.

Keywords: Network coding, Wireless ad hoc network, Wireless LAN,
Performance evaluation.