WDM transmission at 2μm over low-loss hollow core photonic bandgap fiber

World's first demonstration of WDM transmission in a HC-PBGF at the predicted low loss region of 2m is presented. A total capacity of 16 Gbit/s is achieved using 1×8.5 Gbit/s and 3×2.5 Gbit/s channels modulated using NRZ OOK over 290 meters of hollow core fiber

First demonstration of 2μm data transmission in a low-loss hollow core photonic Bandgap fiber

The first demonstration of a hollow core photonic bandgap fiber suitable for high-rate data transmission at 2µm is presented. Using a custom built Thulium doped fiber amplifier, error-free 8Gbit/s transmission in an optically amplified data channel at 2008nm is reported for the first time

The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients

Fibre Optic Sensors for Dynamic Signal Detection

There is both commercial and practical demand to extend the applications for which fibre optic sensors are used. This thesis describes the development of fibre optic sensors and systems for security and defence applications, based on established fibre-optic hydrophone I technology. Dynamic acoustic and seismic signals have been detected with sensor arrays, and used to demonstrate the detection of targets. Achievements have been made in the development and characterisation of entirely novel designs of fibre optic accelerometers and microphones, with the demonstration of arrays of these in practical application to intruder detection and the location of distant acoustic sources. Several prototypes of both acoustic and seismic sensors have been developed. Research efforts focused on designing ,,/ . /~nd establishing the perfonnance of these sensors, then refining the strongest designs for incorporation into arrays of sensors. These arrays have been deployed in environments representative of real operational deployment situations, extending the proof of principle established in the laboratory to demonstration in the field. Specifically, six entirely novel· fibre optic microphone designs are presented, concerning both intensity and interferometric schemes, and evaluated for responsivity and suitability to the location of acoustic targets in a battlefield application. The strongest of these is identified to be a foam-backed fibre wrapped mandrel, of simple design and high responsivity, and readily multiplexed into and interrogated with an inter~rometric system. An array of such foam-backed mandrel microphones is also demonstrated in the field and shown to have very good target location capability at ranges in excess of lkm. In other work, an entirely novel design of fibre optic accelerometer is presented, and theresponse of this is characterised in detail, in terms of both responsivity and the impact of the sensor set-up condition on responsivity. A buried array of such accelerometers combined with distributed cable sensors is demonstrated in a field deployment detecting the presence of signals from an intruder in the region of the array.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Love in livery. An original farce in one act.

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Discrimination of fluvial and eolian features on large ignimbrite sheets around La Pacana Caldera, Chile, using Landsat and SRTM-derived DEM

Satellite images and ground-based observations were used to investigate the morphology and origin of valleys and ridges across large ignimbrite provinces around La Pacana Caldera, N. Chile. We studied 12 separate sites that included five different ignimbrite units that range in age from 5.6 ± 0.5 Ma to 1.35 ± 0.15 Ma. Over 400 features from within these study sites were quantified. Study sites typically have dimensions of 25 × 35 km. Measurements were made using Landsat TM, ETM+, and SRTM-derived DEM and Shaded Relief images. Morphological measurements were made of the ridges and channels, including the direction of regional slope, length, orientation and gradient of each feature. A classification of the different ignimbrite erosion influences, resulting in varying landscape morphologies identified 4 landscape types; Fluvial, Eolian, Modified and Complex. We conclude that the most prevalent features are fluvial-derived channels but the most distinctive are linear, wind-derived ridges. The orientation of these ridges suggests that strong uni-directional winds from the northwest have been constant over a long period of time (> 1 My)

First demonstration of a 2µm OTDR and its use in photonic bandgap CO2 sensing fiber

We report the first demonstration of an optical time domain reflectometer (OTDR) designed for the emerging wavelength band of 2 µm. A dynamic range of 30 dB with a spatial resolution of 5 m is achieved. The characterization of three different fibers using the 2 µm OTDR is described. Two solid core fibers (SMF with a cutoff at 1.7 µm and SMF 28e) have been probed to ascertain their transmission loss values, while measurements in a 19-cell hollow core photonic bandgap fiber show the presence of carbon dioxide gas in the fiber core and allow the contribution that it makes to the fiber loss to be quantified