Lighting as a Circadian Rhythm-Entraining and Alertness-Enhancing Stimulus in the Submarine Environment

The human brain can only accommodate a circadian rhythm that closely follows 24 hours. Thus, for a work schedule to meet the brain’s hard-wired requirement, it must employ a 24 hour-based program. However, the 6 hours on, 12 hours off (6/12) submarine watchstanding schedule creates an 18-hour “day” that Submariners must follow. Clearly, the 6/12 schedule categorically fails to meet the brain’s operational design, and no schedule other than one tuned to the brain’s 24 hour rhythm can optimize performance. Providing Submariners with a 24 hour-based watchstanding schedule—combined with effective circadian entrainment techniques using carefully-timed exposure to light—would allow crewmembers to work at the peak of their daily performance cycle and acquire more restorative sleep. In the submarine environment, where access to natural light is absent, electric lighting can play an important role in actively entraining—and closely maintaining—circadian regulation. Another area that is likely to have particular importance in the submarine environment is the potential effect of light to help restore or maintain alertness

Low Gain Avalanche Detectors (LGAD) for particle physics and synchrotron applications

A new avalanche silicon detector concept is introduced with a low gain in the region of ten, known as a Low Gain Avalanche Detector, LGAD. The detector's characteristics are simulated via a full process simulation to obtain the required doping profiles which demonstrate the desired operational characteristics of high breakdown voltage (500 V) and a gain of 10 at 200 V reverse bias for X-ray detection. The first low gain avalanche detectors fabricated by Micron Semiconductor Ltd are presented. The doping profiles of the multiplication junctions were measured with SIMS and reproduced by simulating the full fabrication process which enabled further development of the manufacturing process. The detectors are 300 μm thick p-type silicon with a resistivity of 8.5 kΩcm, which fully depletes at 116 V. The current characteristics are presented and demonstrate breakdown voltages in excess of 500 V and a current density of 40 to 100 nAcm−2 before breakdown measured at 20oC. The gain of the LGAD has been measured with a red laser (660 nm) and shown to be between 9 and 12 for an external bias voltage range from 150 V to 300 V

Middle class parental aspiration and the transmission of advantage in contrasting locales

This thesis investigated parental aspirations regarding children's futurity, how they relate to parenting styles and to what extent their sense of belonging to their neighbourhood might be underpinned by values, personal and intergenerational biography and resources. This study considered how families help to reproduce social advantage and disadvantage through the perspective of Bourdieu's conceptual framework regarding social and cultural reproduction, with the family viewed as a habitus generating institution. Taken from a series of semi-­structured interviews with parents of children at key transition points in the English primary school, qualitative data examined parental aspirations for children's futurity in three urban settings. In this thesis it is argued that locational habitus can be seen as a structuring device, mediated through embodied capital within education, cultural practices and family socialisation. Findings from this study illuminated how some parents are seeking to map the life of their children, particularly through the acquisition of specific personality traits which facilitate social fluency, adaptability and resilience. An original contribution arising from this research is how these desirable dispositions are transformative at times of transition and form the basis for future occupational competencies. Findings also propose changing parental attitudes to higher education with ambiguity regarding the pursuit of a university degree accentuated by high tuition fees, economic instability and uncertainty as to its value and whether future investment is likely to be suitably rewarded. No longer seen as purely securing educational advantage based upon the value of a 'good degree', parental rationale for university attendance is more explicitly linked to the accumulation of personal capital to maximise employability

Solitons in the Yakushevich model of DNA beyond the contact approximation

The Yakushevich model of DNA torsion dynamics supports soliton solutions, which are supposed to be of special interest for DNA transcription. In the discussion of the model, one usually adopts the approximation $\ell_0 \to 0$, where $\ell_0$ is a parameter related to the equilibrium distance between bases in a Watson-Crick pair. Here we analyze the Yakushevich model without $\ell_0 \to 0$. The model still supports soliton solutions indexed by two winding numbers $(n,m)$; we discuss in detail the fundamental solitons, corresponding to winding numbers (1,0) and (0,1) respectively

Nonperturbative study of the two-frequency sine-Gordon model

The two-frequency sine-Gordon model is examined. The focus is mainly on the case when the ratio of the frequencies is 1/2, given the recent interest in the literature. We discuss the model both in a perturbative (form factor perturbation theory) and a nonperturbative (truncated conformal space approach) framework, and give particular attention to a phase transition conjectured earlier by Delfino and Mussardo. We give substantial evidence that the transition is of second order and that it is in the Ising universality class. Furthermore, we check the UV-IR operator correspondence and conjecture the phase diagram of the theory.Comment: Minor corrections, LaTeX2e, 39 pages, 26 figures (4 pslatex, 1 postscript and 21 eps

Performance evaluation of novel square-bordered position-sensitive silicon detectors with four-corner readout

We report on a recently developed novel type of large area (62 mm x 62 mm) position sensitive silicon detector with four-corner readout. It consists of a square-shaped ion-implanted resistive anode framed by additional low-resistivity strips with resistances smaller than the anode surface resistance by a factor of 2. The detector position linearity, position resolution, and energy resolution were measured with alpha-particles and heavy ions. In-beam experimental results reveal a position resolution below 1 mm (FWHM) and a very good non-linearity of less than 1% (rms). The energy resolution determined from 228Th alpha source measurements is around 2% (FWHM).Comment: 13 pages, 10 figures, submitted to Nucl. Instr. and Meth.

26.5 ps Time Resolution Using 50 {\mu}m Low Gain Avalanche Detectors Fabricated by Micron Semiconductor Ltd

Low Gain Avalanche Detectors (LGADs) are silicon semiconductor sensors with an implanted thin p-doped multiplication layer that is designed to provide low gain. Most importantly, LGADs are specifically engineered to provide excellent spatial and temporal resolution simultaneously. The technology shows promising prospects of fulfilling the 4D tracking requirements of future high energy physics experiments. Micron Semiconductor Ltd. has fabricated LGADs with an active thickness of 50 $\mu$m. The electrical and timing performance has been measured and compared with devices fabricated at IMB-CNM for reference. 50 $\mu$m thin LGADs by Micron Semiconductor Ltd. were measured to have a timing resolution in the region of 30 ps using a dedicated setup involving minimum ionising particles produced by Sr-90. Specifically, the best timing resolution of 26.5 ps was measured at a bias voltage of 200 V at -30{\deg}C