Post-"pill" amenorrhoea--cause or coincidence?

The relationship of contraceptive history to diagnostic category of amenorrhoea was analysed in 131 consecutively investigated cases of secondary amenorrhoea. Amenorrhoea occurred in 52 patients immediately after discontinuing the oral contraceptive. Twenty-two had had amenorrhoea before oral contraceptive treatment and 23 patients before the episode of non-contraceptive-related amenorrhoea investigated here. When these cases were excluded from analysis there was no significant difference in the distribution of any of the diagnostic categories between those who had used the oral contraceptive and those who had not. The results suggest that using oral contraceptives does not cause subsequent amenorrhoea.     

Negative effects revisited: A rejoinder.

Responds to A. E. Bergin's critique (see record 1981-08376-001) of the present authors' article (see record 1981-08419-001). Arguments that Bergin offers to support his conclusion that therapy causes deterioration are evaluated. If psychotherapy causes deterioration, one would expect to find at least one adequate outcome study in which a higher rate of decline occurs among the treated patients. This study has yet to be found. (12 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stress and rewards in women's multiple roles: The case of women in the middle.

Examined stress and rewards experienced by 95 women who were simultaneously occupying the roles of caregiver, mother, and wife. The study examined role-specific stress and rewards as predictors of well-being (physical health, positive affect, negative affect, and role overload) and examined the effects of an accumulation of role stress and role rewards across these 3 roles. Role rewards contributed unique variance to well-being, even after role stress had been considered. An accumulation of role stress across roles was related to poorer well-being, whereas an accumulation of role rewards was related to better well-being. Findings indicate that caregivers' experiences in multiple roles could both detract from and enhance their mental and physical health. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Anion distribution in alkaline silicates

Alkaline sodium silicates have been prepared by heating sodium carbonate and silica mixtures in the mole ratio of 2.51.The silicates have been examined by chronopotentiometric and thermogravimetric methods. The electro-analytical technique has allowed the identification of the oxy-anions SiO₄ ^4–, Si₂O₇ ^6– and Si₃O₁₀ ^8– by their electro-reduction at cathodic potentials with reference to a graphite anode of approximately –1.0, –1.6, –2.0 V respectively.     

Electroanalysis of iron in molten slags

It has been found, using chronopotentiometry, that ferric and ferrous ions in sodium disilicate at 950° C act as separate reducible species. The electrode processes have been examined and the diffusion coefficients have been determined.Using known weights of ferric oxide and ferrous oxalate in sodium disilicate glass, calibration curves have been obtained. These gave a good agreement between experimental and estimated values for mixtures of ferric and ferrous ions and suggest that the electroanalytical method could be suitable for the examination of ferric/ferrous ratios in steel-making slags.     

Learning agent influence in MAS with complex social networks

In complex open multi-agent systems (MAS), where there is no centralised control and individuals have equal authority, ensuring cooperative and coordinated behaviour is challenging. Norms and conventions are useful means of supporting cooperation in an emergent decentralised manner, however it takes time for effective norms and conventions to emerge. Identifying influential individuals enables the targeted seeding of desirable norms and conventions, which can reduce the establishment time and increase efficacy. Existing research is limited with respect to considering (i) how to identify influential agents, (ii) the extent to which network location imbues influence on an agent, and (iii) the extent to which different network structures affect influence. In this paper, we propose a methodology for learning a model for predicting the network value of an agent, in terms of the extent to which it can influence the rest of the population. Applying our methodology, we show that exploiting knowledge of the network structure can significantly increase the ability of individuals to influence which convention emerges. We evaluate our methodology in the context of two agent-interaction models, namely, the language coordination domain used by Salazar et al. (AI Communications 23(4): 357–372, 2010) and a coordination game of the form used by Sen and Airiau (in: Proceedings of the 20th International Joint Conference on Artificial Intelligence, 2007) with heterogeneous agent learning mechanisms, and on a variety of synthetic and real-world networks. We further show that (i) the models resulting from our methodology are effective in predicting influential network locations, (ii) there are very few locations that can be classified as influential in typical networks, (iii) four single metrics are robustly indicative of influence across a range of network structures, and (iv) our methodology learns which single metric or combined measure is the best predictor of influence in a given network.     

Reflection X-ray microscopy

X-ray microscopy has an important role to play both in microstructural studies of materials and in the examination of high temperature plasmas. Reflection microscopy offers some advantages over other types of X-ray microscopy in the range of wavelengths which can be employed, in its potential for absorption analysis and in the ultimate resolution of about 10 nm, which may be achieved in favourable circumstances. In the first of a series of microscopes now under development, submicrometre resolution has been achieved at a wavelength of 0.8 nm.     

Freeze casting for near‐net‐shaping of dense zirconium diboride ceramics

Zirconium diboride (ZrB₂) was formed into dense complex shapes using freeze casting as a near‐net‐shaping technique. Aqueous‐based formulations were compared with nonaqueous (cyclohexane) based formulations in terms of rheological behavior, particle packing in the green body, sintered density, macroscale porosity, and cracking. The influence of particle solids concentration and freezing rate was investigated. The aqueous formulations were found to be deficient in that they produced macroscale porosity that could not be eliminated during sintering resulting in low density and large pores in the final shaped objects. The nonaqueous‐based system was able to produce complex shaped objects with significantly reduced macroscale porosity. The higher concentration of solids in the nonaqueous‐based formulations was primarily responsible for the reduced macroscale porosity and enabled higher sintered densities (up to 90%‐91.5% of theoretical density for fast freezing). The microstructure of the ZrB₂ formed at fast freezing rates and high solids content typically had isolated pores in the order of 5‐10 μm in size, mainly found along grain boundaries (grain sizes between 20 and 50 μm). Although this rapid freezing produced denser components, it tended to produce objects with internal cracks. When slower freezing rates were used, intricate complex shaped objects could be produced without cracks but their density was only between 65% and 80% of theoretical density.