University of Aberdeen

About: University of Aberdeen is a education organization based out in Aberdeen, United Kingdom. It is known for research contribution in the topics: Population & Randomized controlled trial. The organization has 21174 authors who have published 49962 publications receiving 2105479 citations. The organization is also known as: Aberdeen University.

The detection of inter-turn short circuits in the stator windings of operating motors

Abstract: This paper develops a winding-function-based method for modeling polyphase cage induction motors with inter-turn short circuits in the machine stator winding. Analytical consideration which sheds light on some components of the stator current spectra of both healthy and faulty machines is developed. It is shown that, as a result of the nature of the cage rotor, no new frequency components of the line current spectra can appear as a consequence of the fault. Only a rise in some of the frequency components which already exist in the line current spectra of a healthy machine can be observed. An experimental setup comprising a 3 kW delta-connected motor loaded by a generator was used to validate this approach. The experimental results obtained clearly validate the analytical and simulation results.

Reversible neural inactivation reveals hippocampal participation in several memory processes.

Abstract: Studies of patients and animals with brain lesions have implicated the hippocampal formation in spatial, declarative/relational and episodic types of memory. These and other types of memory consist of a series of interdependent but potentially dissociable memory processes—encoding, storage, consolidation and retrieval. To identify whether hippocampal activity contributes to these processes independently, we used a novel method of inactivating synaptic transmission using a water-soluble antagonist of AMPA/kainate glutamate receptors. Once calibrated using electrophysiological and two-deoxyglucose techniques in vivo, drug or vehicle was infused chronically or acutely into the dorsal hippocampus of rats at appropriate times during or after training in a water maze. Our findings indicate that hippocampal neural activity is necessary for both encoding and retrieval of spatial memory and for either trace consolidation or long-term storage.

Competition for land

Abstract: A key challenge for humanity is how a future global population of 9 billion can all be fed healthily and sustainably. Here, we review how competition for land is influenced by other drivers and pre...

Chronic pain and quality of life following open inguinal hernia repair.

Abstract: Background: The aim was to determine the frequency and characteristics of chronic pain following open inguinal hernia repair and to identify risk factors for its development. Methods: This was a questionnaire survey of a historical cohort of patients who underwent inguinal hernia surgery in Aberdeen. The sample comprised all patients (n = 351) who underwent surgery between January 1995 and December 1997, and who were alive and resident in Grampian in October 1999. Outcome measures included self-report of pain persisting for more than 3 months after operation. Pain was characterized by means of the McGill Pain Questionnaire, and quality of life was assessed with the Short Form 36 (SF-36). Results: A total of 226 patients (64 per cent) completed the questionnaire, 67 (30 per cent) of whom reported chronic pain. Reported pain was predominantly neuropathic in character. Patients at increased risk of chronic pain were under 40 years old (P < 0.001), had day-case surgery (P = 0.004), had subsequent surgery on the same side (P < 0.005) and recalled pain before operation (P = 0.005). The SF-36 scores were significantly different in the social functioning, mental health and pain dimensions in patients with chronic pain. Conclusion: Chronic pain occurred in 30 per cent of patients after open hernia repair, a higher frequency than has been reported previously. Several risk factors were identified and further prospective research is recommended.