Staying in the science stream: patterns of participation in A-level science subjects in the UK.

This paper describes patterns of participation and attainment in A-level physics, chemistry and biology from 1961 to 2009. The A-level has long been seen as an important gateway qualification for higher level study, particularly in the sciences. This long term overview examines how recruitment to these three subjects has changed in the context of numerous policies and initiatives that seek to retain more young people in the sciences. The results show that recruitment to the pure sciences has stagnated, general trends have hardly varied and the track record of government policy in influencing change is not strong. There is no evidence for increasing achievement gaps between the sexes at A-level and even national policy requiring that all young people study science up to the age of 16 appears to have had little impact on recruitment at this leve

Discourse and identity in a corpus of lesbian erotica

This article uses corpus linguistic methodologies to explore representations of lesbian desires and identities in a corpus of lesbian erotica from the 1980s and 1990s. We provide a critical examination of the ways in which “lesbian gender,” power, and desire are represented, (re-)produced, and enacted, often in ways that challenge hegemonic discourses of gender and sexuality. By examining word frequencies and collocations, we critically analyze some of the themes, processes, and patterns of representation in the texts. Although rooted in linguistics, we hope this article provides an accessible, interdisciplinary, and timely contribution toward developing understandings of discursive practices surrounding gender and sexuality

Milestones: a mixed methods study of an educational intervention to improve care of the dying

Background: Approximately 460 000 people die annually in England. Three-quarters of these deaths are expected. Health Education England is prioritising upskilling of clinical staff in response to reports of poor care quality in the last days of life in acute hospitals, where almost half of all deaths occur. This study explores the impact of an end-of-life care (EoLC) educational intervention, Milestones, in acute hospital trusts in Greater London. Methods: This is a mixed methods study. Learners completed a questionnaire pre- (n=452), immediately post- (n=488) and 3 to 8 months post- (n=37) intervention. The questionnaire measured learner confidence in EoLC covering the National Health Service adopted ‘Priorities for the Care of the Dying Person’. Paired t-tests were used to determine statistically significant difference in learner confidence pre- and post-intervention. A convenience sample of learners (n=7) and educators (n=5) were recruited to qualitative semi-structured interviews that sought to understand if, how and why Milestones worked. Data were analysed using a thematic approach. Results: A statistically significant increase in learner confidence across all five priorities of care’ was sustained up to 8 months (p<0.001). Interviewees wanted to discuss wider challenges in EoLC related to the organisations and cultural contexts in which they worked. Concerns included balancing hope when decision-making, learning as a multidisciplinary team and emotional impact. Conclusion: The findings suggest that Milestones is a flexible, beneficial resource for teaching EoLC that facilitates enhanced learner engagement. Understanding generated about wider concerns can inform future educational material development, organisational process and research study design

Structural determinants and regulation of spontaneous activity in GABAA receptors

GABA_{A} receptors are vital for controlling neuronal excitability and can display significant levels of constitutive activity that contributes to tonic inhibition. However, the mechanisms underlying spontaneity are poorly understood. Here we demonstrate a strict requirement for β3 subunit incorporation into receptors for spontaneous gating, facilitated by α4, α6 and δ subunits. The crucial molecular determinant involves four amino acids (GKER) in the β3 subunit's extracellular domain, which interacts with adjacent receptor subunits to promote transition to activated, open channel conformations. Spontaneous activity is further regulated by β3 subunit phosphorylation and by allosteric modulators including neurosteroids and benzodiazepines. Promoting spontaneous activity reduced neuronal excitability, indicating that spontaneous currents will alter neural network activity. This study demonstrates how regional diversity in GABA_{A} receptor isoform, protein kinase activity, and neurosteroid levels, can impact on tonic inhibition through the modulation of spontaneous GABA_{A} receptor gating

An Atom Michelson Interferometer on a Chip Using a Bose-Einstein Condensate

An atom Michelson interferometer is implemented on an "atom chip." The chip uses lithographically patterned conductors and external magnetic fields to produce and guide a Bose-Einstein condensate. Splitting, reflecting, and recombining of condensate atoms are achieved by a standing-wave light field having a wave vector aligned along the atom waveguide. A differential phase shift between the two arms of the interferometer is introduced by either a magnetic-field gradient or with an initial condensate velocity. Interference contrast is still observable at 20% with atom propagation time of 10 ms

Tip-Clearance Actuation With Magnetic Bearings for High-Speed Compressor Stall Control

Magnetic bearings are widely used as active suspension devices in rotating machinery, mainly for active vibration control purposes. The concept of active tip clearance control suggests a new application of magnetic bearings as servo-actuators to stabilize rotating stall in axial compressors. This paper presents a first-of-a-kind feasibility study of an active stall control experiment with a magnetic bearing servo-actuator in the NASA Glenn high-speed single-stage compressor test facility. Together with CFD and experimental data a two-dimensional, incompressible compressor stability model was used in a stochastic estimation and control analysis to determine the required magnetic bearing performance for compressor stall control. The resulting requirements introduced new challenges to the magnetic bearing actuator design. A magnetic bearing servo-actuator was designed which fulfilled the performance specifications. Control laws were then developed to stabilize the compressor shaft. In a second control loop, a constant gain controller was implemented to stabilize rotating stall. A detailed closed loop simulation at 100% corrected design speed resulted in a 2.3% reduction of stalling mass flow which is comparable to results obtained in the same compressor by Weigl et al. (1998) using unsteady air injection. The design and simulation results presented here establish the viability of magnetic bearings for stall control in aero-engine high-speed compressors. Furthermore the paper outlines a general design procedure to develop magnetic bearing servo-actuators for high-speed turbomachinery.United States. National Aeronautics and Space Administration (Grant NAG3-1457

REVIEWS: Professional Materials

Jerry L. Johns (1991). Basic Reading Inventory; Children\u27s Books: Merry Christmas, Amanda and April; Chicken Man; All the Lights in the Night; Jack and the Beanstalk; The Swineherd; The Worst Person\u27s Christmas; That\u27s Exactly the Way it Wasn’t; An Auto Mechanic, A Carpenter, A Potter; Meredith\u27s Mother Takes the Trai

Bacteriological assessment of some borehole water samples in Mile 50, Abakaliki, Ebonyi State, Nigeria

Water as excellent natural resource is meant to be of high quality to reduce the outbreak of water-borne diseases. Bacteriological load of some borehole water samples in Mile 50 Abakaliki were carried out to determine their potability. Fifteen borehole water samples were sampled during rainy and dry season from June to July and November to December 2018 respectively. The total bacterial count was determined by tenfold serial dilution method using peptone water. Eight bacterial species namely Vibrio cholerae, Pseudomonas aeroginosa, Escherichia coli, Staphylococcus aureus, Salmonella typhi, Shigella flexineri, Proteus vulgaris and Klebsiella&nbsp; pneumoniaewere isolated using standard analytical procedures. The bacterium that had the highest frequency of occurrence during both rainy and dry season’s was K. pneumoniae with percentage frequency of&nbsp; 21.81% and 20.79%&nbsp; respectively, and P. vulgaris had the least value of 6.96% during rainy season. E. coli and S. aureus have the least value of 5.94% during dry season. Amoxicillin (30ug) was mostly resisted by the bacterial isolates why being was more susceptible to Ciprofloxacin (10ug) among the antibiotics used for susceptibility test. Two way analysis of variance (ANOVA) was used to determine the level of significance among the bacteriological analyses of both seasons. Therefore, there is need to create awareness about the present situation of the borehole waters and the necessity for further treatment of water by consumers, before it can be used for both drinking and domestic purposes to prevent disease outbreak in the area

Effective Hamiltonian Approach to Hyperon Beta Decay with Final-State Baryon Polarization

Using an effective Hamiltonian approach, we obtain expressions for hyperon beta decay final-state baryon polarization. Terms through second order in the energy release are retained. The resulting approximate expressions are much simpler and more compact than the exact expressions, and they agree closely with them.Comment: 1 Figure Will appear in Phys Rev D 60 Article 117505 (Dec 1, 1999