Bolometric and non-bolometric radio frequency detection in a metallic single-walled carbon nanotube

We characterize radio frequency detection in a high-quality metallic single-walled carbon nanotube. At a bath temperature of 77 K, only bolometric (thermal) detection is seen. At a bath temperature of 4.2 K and low bias current, the response is due instead to the electrical nonlinearity of the non-ohmic contacts. At higher bias currents, the contacts recover ohmic behavior and the observed response agrees well with the calculated bolometric responsivity. The bolometric response is expected to operate at terahertz frequencies, and we discuss some of the practical issues associated with developing high frequency detectors based on carbon nanotubes.Comment: 11 pages (double-spaced), 3 figure

Tonal structure and pitch targets in Italian focus constituents

This work investigates the tonal structure of the focal accent in narrow focus statements of Neapolitan Italian. The formal properties of this accent lend themselves to two competing analyses. Specifically, this accent could equally be described as a HL accentual fall or as a LH rise. The two analyses were evaluated on the basis of a set of utterances containing focus constituents with varying number of words. Long narrow focus constituents present in fact a medial F0 minimum that appears to be an actual tonal target. Such a target might be part of either a HL or of a LH accent. Tonal as well as timing evidence appear to lend support to the LH hypothesis. An important consequence is that the final fall of statement focus constituents must be analyzed as a tonal event that is separate from the nuclear pitch accent and is analogous to the question final fall.Aquest article investiga l'estructura tonal de l'accent focal de les oracions declaratives amb focus estret en italià de Nàpols. Les propietats formals de l'accent focal es podrien en principi analitzar de dues maneres possibles, bé com un accent tonal HL de tipus descendent o bé com un accent tonal LH de tipus ascendent. Les dues possibles anàlisis són avaluades en funció del comportament de l'accent tonal en constituents que contenen un nombre variable de mots. Els constituents focalitzats presenten una vall d'F0 que es comporta com un clar objectiu entonatiu. Aquest punt d'inflexió podria ser part també d'un accent HL o LH. Indicis tonals i temporals donen suport a la hipòtesi que es tracta d'un accent tonal ascendent. D'aquesta anàlisi se'n deriva el fet que el moviment tonal descendent final de les oracions declaratives s'ha d'analitzar com un gest tonal diferent de l'accent nuclear i que aquest es comporta de forma anàloga al to de frontera ascendent final de les oracions interrogatives

Energy loss of the electron system in individual single-walled carbon nanotubes

We characterize the energy loss of the non-equilibrium electron system in individual metallic single-walled carbon nanotubes at low temperature. Using Johnson noise thermometry, we demonstrate that, for a nanotube with ohmic contacts, the dc resistance at finite bias current directly reflects the average electron temperature. This enables a straightforward determination of the thermal conductance associated with cooling of the nanotube electron system. In analyzing the temperature- and length-dependence of the thermal conductance, we consider contributions from acoustic phonon emission, optical phonon emission, and hot electron outdiffusion.Comment: 16 pages, including supporting information; to appear in Nano Letter

Psychological and cultural determinants of women's intentions to donate oocytes.

In oocyte donation, oocytes from one woman can be transferred to another for fertility treatment or used for medical research. However, there is an acute shortage of women from the general population donating their oocytes and this has adverse consequences for infertile patients and medical researchers. The aims of this thesis were to explore the psychological determinants of oocyte donation intentions and to investigate the link between oocyte donation intentions and parenthood using components of the Theory of Planned Behaviour (TPB) among women from different ethnic backgrounds. In doing so, a triangulation approach was adopted and one systematic review and five empirical investigations consisting of quantitative, qualitative and experimental research methodologies were carried out. Results revealed that oocyte donation is best accounted for by a diverse dimension of factors, which include positive attitudes towards oocyte donation, unconventional perceptions of parenthood and demographic variables. Some theoretical components of the TPB were supported; in particular Structural Equation Modelling found positive attitudes towards oocyte donation and subjective norms demonstrated a direct influence on the decision to donate oocytes. However, the role of perceived behavioural control in intentions to donate remains uncertain. Perceptions of the importance of parenthood and genetic ties between parent and child are key in determining [un]willingness to donate oocytes for fertility treatment. In addition, findings from this thesis suggest that it may be possible to modify intentions towards oocyte donation using the Framing Effect among White women, but not Women from South East Asia. The results of this thesis have some important implications for research and clinical practice, particularly in its potential to tailor clinical service provision regarding the recruitment of oocyte donors

In situ detection of airbourne fibres by light scattering

Imperial Users onl

The Bio-Politics of Population Control and Sex Selective Abortion in China and India

China and India, two countries with skewed sex ratios in favor of males, have introduced a wide range of policies over the past few decades to prevent couples from deselecting daughters, including criminalizing sex-selective abortion through legal jurisdiction. This article aims to analyze how such policies are situated within the bio-politics of population control and how some of the outcomes reflect each government’s inadequacy in addressing the social dynamics around abortion decision making and the social, physical, and psychological effects on women’s wellbeing in the face of criminalization of sex-selective abortion. The analysis finds that overall, the criminalization of sex selection has not been successful in these two countries. Further, the broader economic, social, and cultural dynamics which produce bias against females must be a part of the strategy to combat sex selection, rather than a narrow criminalization of abortion which endangers women’s access to safe reproductive health services and their social, physical, and psychological wellbeing

The multidisciplinary management of type 2 and gestational diabetes in pregnancy

The UK is experiencing a dramatic increase in the prevalence of type 2 diabetes mellitus (T2D). Consequently, there is a corresponding increase in diabetes in pregnancy, with 87.5% of pregnancies in the UK complicated by diabetes due to gestational diabetes mellitus (GDM), and 27% of those with pre-existing diabetes having T2D (National Centre for Health and Clinical Excellence (NICE), 2008a). Although the risks to mother and baby are similar to type 1 diabetes (T1D), the approach and management often differ. Women with GDM and T2D are more likely to be older, multiparous and live in deprived areas. Certain ethnic groups are more prone to GDM and T2D, and there is a strong association between being overweight or obese and diabetes. Women who develop GDM in pregnancy also have an increased risk of T2D in later life (Diabetes UK, 2011a). Some surveys, such as the Confidential Enquiry into Maternal and Child Health (CEMACH, 2007a) have shown that women with T2D often receive suboptimum care prior to conception and in early pregnancy. This paper presents an overview of the multidisciplinary management of T2D and GDM in pregnancy and identifies areas where care may be lacking for these women

Determination of Arsenic, Mercury and Barium in herbarium mount paper using dynamic ultrasound-assisted extraction prior to atomic fluorescence and absorption spectrometry

A dynamic ultrasound-assisted extraction method using Atomic Absorption and Atomic Flourescence spectrometers as detectors was developed to analyse mercury, arsenic and barium from herbarium mount paper originating from the herbarium collection of the National Museum of Wales. The variables influencing extraction were optimised by a multivariate approach. The optimal conditions were found to be 1% HNO3 extractant solution used at a flow rate of 1 mL min-1. The duty cycle and amplitude of the ultrasonic probe was found to be 50% in both cases with an ultrasound power of 400 W. The optimal distance between the probe and the top face of the extraction chamber was found to be 0 cm. Under these conditions the time required for complete extraction of the three analytes was 25 min. Cold vapour and hydride generation coupled to atomic fluorescence spectrometry was utilized to determine mercury and arsenic, respectively. The chemical and instrumental conditions were optimized to provide detection limits of 0.01ng g-1 and 1.25 ng g-1 for mercury and arsenic, respectively. Barium was determined by graphite-furnace atomic absorption spectrometry, with a detection limit of 25 ng g-1. By using 0.5 g of sample, the concentrations of the target analytes varied for the different types of paper and ranged between 0.4–2.55 µg g-1 for Ba, 0.035–10.47 µg g-1 for As and 0.0046–2.37 µg g-1 for Hg

The effectiveness of persuasive health communication techniques

Objective: This study tests the effectiveness of Framing and Fear conditions to change attitudes towards elective single embryo transfer (eSET) in a large, non-clinical population. Method:A repeated measures randomised control trial design was used with 632 male and female participants allocated to one of two intervention groups (Framing or Fear condition) or a control group. There were two conditions in the Framing group (gain or loss frame), three conditions in the Fear group (high, medium or low fear) and two control conditions (education and non-education). Questionnaires were completed before exposure to the message (time 1) and immediately afterwards (time 2). Results: High fear (β = .637, P<0.008) and gain frame (β = .718, P<0.005) were the only significant conditions predicting hypothetical intentions towards eSET at Time 2 for the total sample. No other conditions were predictive of hypothetical intentions. Education only improved knowledge and non-education showed no changes in scores. Conclusion: These results highlight the benefits of multidisciplinary expertise in designing health promotion to reduce multiple pregnancies. Practice Implications: Findings suggest that educational material needs to be presented along- side persuasive communication techniques incorporating high fear and gain frames to help promote eSET in clinical practice