The construction of an aptitude test for particular ability in the bookkeeping and accounting field.

Thesis (Ed.D.)--Boston University

A Review of the Use of Resorbable Plateing Systems in Cranio-Maxillofacial Surgery

Resorbable materials have been used for many different procedures in cranio-maxillofacial surgery. However, they have had varying rates of success. The use of resorbable for oncological reconstruction is a relatively new area, compared with paediatric trauma and orthognathic surgery

Field tests of a portable MEMS gravimeter

Gravimeters are used to measure density anomalies under the ground. They are applied in many different fields from volcanology to oil and gas exploration, but present commercial systems are costly and massive. A new type of gravity sensor has been developed that utilises the same fabrication methods as those used to make mobile phone accelerometers. In this study, we describe the first results of a field-portable microelectromechanical system (MEMS) gravimeter. The stability of the gravimeter is demonstrated through undertaking a multi-day measurement with a standard deviation of 5.58 × 10−6 ms−2 . It is then demonstrated that a change in gravitational acceleration of 4.5 × 10−5 ms−2 can be measured as the device is moved between the top and the bottom of a 20.7 m lift shaft with a signal-to-noise ratio (SNR) of 14.25. Finally, the device is demonstrated to be stable in a more harsh environment: a 4.5 × 10−4 ms−2 gravity variation is measured between the top and bottom of a 275-m hill with an SNR of 15.88. These initial field-tests are an important step towards a chip-sized gravity senso

Restructuring the Defined Benefit Pension

Under the traditional approach to defined benefit plans, well-intended disciplinary and regulatory regimes have sought to restrict discretion, reduce uncertainty and risk, and protect workers and employers. Nevertheless the discouraging state of US defined benefit plans indicates that past efforts have gone awry. This chapter suggests that a new approach to defined benefit plans could resurrect the key elements required for retirement income security, rather than pursuing piecemeal reform

The White-Eyed Blowout fracture in the child: beware of distractions

Inferior ‘trapdoor’ orbital floor fractures with muscle and soft tissue incarceration are the most common type of orbital fracture in children. Delays to treatment can lead to a significant morbidity. It has been recommended that children who present with a ‘white-eyed blowout’ fracture should have surgery performed within 48 h of diagnosis, otherwise prognosis is poor. A 14-year-old boy was initially misdiagnosed with a head injury due to the minor appearance of his orbital injury and his presenting complaint of nausea and vomiting. This resulted in a significant delay to surgery. The oculovagal reflex associated with orbital injuries is well documented (Wei and Durairaj in Pediatric orbital floor fractures. J AAPOS 2011;15:173–80). It should be considered by emergency department and paediatric staff when dealing with patients who have sustained a blow to the orbital region, despite not having a subconjunctival haemorrhage. The importance of examination to detect other features of orbital blow-out and entrapment are stressed

Do we forget to treat concussion?

Although the absolute definition is often debated, concussion can be defined as a temporary disruption in normal brain function after a mechanical impact or transmission of force through cerebral tissue. A frequent misconception in the diagnosis is that an individual must have ‘lost consciousness’ to have become concussed; this is not the case. A temporary loss of function may be manifested as blurring of vision, confusion or unsteadines

A High Stability Optical Shadow Sensor with Applications for Precision Accelerometers

Gravimeters are devices which measure changes in the value of the gravitational acceleration, \textit{g}. This information is used to infer changes in density under the ground allowing the detection of subsurface voids; mineral, oil and gas reserves; and even the detection of the precursors of volcanic eruptions. A micro-electro mechanical system (MEMS) gravimeter has been fabricated completely in silicon allowing the possibility of cost e-effective, lightweight and small gravimeters. To obtain a measurement of gravity, a highly stable displacement measurement of the MEMS is required. This requires the development of a portable electronics system that has a displacement sensitivity of $\leq 2.5$ nm over a period of a day or more. The portable electronics system presented here has a displacement sensitivity $\leq 10$ nm$/\sqrt{\textrm{Hz}}$ ($\leq 0.6$ nm at $1000$ s). The battery power system used a modulated LED for measurements and required temperature control of the system to $\pm$ 2 mK, monitoring of the tilt to $\pm$ 2 $\mu$radians, the storage of measured data and the transmission of the data to an external server.Comment: 8 Pages, 12 figures, 5 equations, currently submitted and under review at IEEE Sensors SIE

Microelectromechanical system gravimeters as a new tool for gravity imaging

A microelectromechanical system (MEMS) gravimeter has been manufactured with a sensitivity of 40 ppb in an integration time of 1 s. This sensor has been used to measure the Earth tides: the elastic deformation of the globe due to tidal forces. No such measurement has been demonstrated before now with a MEMS gravimeter. Since this measurement, the gravimeter has been miniaturized and tested in the field. Measurements of the free-air and Bouguer effects have been demonstrated by monitoring the change in gravitational acceleration measured while going up and down a lift shaft of 20.7 m, and up and down a local hill of 275 m. These tests demonstrate that the device has the potential to be a useful field-portable instrument. The development of an even smaller device is underway, with a total package size similar to that of a smartphone