No abstract

ObjectiveTo determine whether not waiting for the elimination of direct oral anticoagulants (DOACs) has an effect on the amount of perioperative bleeding in patients who undergo operative treatment of a hip fracture.DesignObservation, retrospective case–control study.SettingA single UK major trauma centre.ParticipantsPatients who sustained a hip fracture were identified using the National Hip Fracture Database (NHFD). All those found to be taking a DOAC at the time of fracture were identified (n=63). A matched group not taking a DOAC was also identified from the NHFD (n=62).Main outcomePerioperative drop in haemoglobin concentration.ResultsThere was no relationship between admission to operation interval and perioperative change in haemoglobin concentration in patients taking DOACs (regression coefficient=−0.06 g/L/hour; 95% CI −0.32–0.20; p=0.64). No relationship was found between the time from admission to operation interval and the probability of transfusion (OR=0.94; 95% CI 0.85 to 1.90; p=0.16) or reoperation (OR=1.04; 95% CI 0.93 to 1.16; p=0.49). One mortality was recorded in the DOAC group within 30 days of admission, and this compared with five in the matched group of patients (p=0.2).ConclusionsDelaying surgery in patients who sustain a hip fracture who are taking a DOAC drug has not been shown to reduce perioperative bleeding or affect their mortality in this study.

The ZigBee specification builds upon IEEE 802.15.4 low-rate wireless personal area standards by adding security and mesh networking functionality. ZigBee networks may be secured through 128-bit encryption keys and by MAC address access control lists, yet these credentials are vulnerable to interception and spoofing via free software tools available over the Internet. This work proposes a multi-factor PHY-MAC-NWK security framework for ZigBee that augments bit-level security using radio frequency (RF) PHY features. These features, or RF fingerprints, can be used to differentiate between dissimilar or like-model wireless devices. Previous PHY-based works on mesh network device differentiation predominantly exploited the signal turn-on region, measured in nanoseconds. For an arbitrary benchmark of 90% or better classification accuracy, this work shows that reliable PHY-based ZigBee device discrimination can be achieved at SNR ≥ 8 dB. This is done using the entire transmission preamble, which is less technically challenging to detect and is over 1000 times longer than the signal turn-on region. This work also introduces a statistical, pre-classification feature ranking technique for identifying relevant features that dramatically reduces the number of RF fingerprint features without sacrificing classification performance.

This paper evaluates the performance of several ad hoc routing protocols in the context of a swarm of autonomous unmanned aerial vehicles (UAVs). It has been proposed that a wireless network where nodes have on average 5.1774 log n neighbors, where n is the total number of network nodes, has a high probability of having no partitions. By decreasing transmission range and implementing multi-hop routing between nodes, while ensuring network connectivity is maintained, spatial multiplexing of the wireless channel is exploited. The proposed process is evaluated using the OPNET network simulation tool for the Greedy Perimeter Stateless Routing (GPSR), Optimized Link State Routing (OLSR), and Ad hoc Ondemand Distance Vector (AODV) routing protocols in the context of a swarm of UAVs.