Nonclassical statistics of intracavity coupled χ(2)\chi^{(2)} waveguides: the quantum optical dimer

A model is proposed where two $\chi^{(2)}$ nonlinear waveguides are contained in a cavity suited for second-harmonic generation. The evanescent wave coupling between the waveguides is considered as weak, and the interplay between this coupling and the nonlinear interaction within the waveguides gives rise to quantum violations of the classical limit. These violations are particularly strong when two instabilities are competing, where twin-beam behavior is found as almost complete noise suppression in the difference of the fundamental intensities. Moreover, close to bistable transitions perfect twin-beam correlations are seen in the sum of the fundamental intensities, and also the self-pulsing instability as well as the transition from symmetric to asymmetric states display nonclassical twin-beam correlations of both fundamental and second-harmonic intensities. The results are based on the full quantum Langevin equations derived from the Hamiltonian and including cavity damping effects. The intensity correlations of the output fields are calculated semi-analytically using a linearized version of the Langevin equations derived through the positive-P representation. Confirmation of the analytical results are obtained by numerical simulations of the nonlinear Langevin equations derived using the truncated Wigner representation.Comment: 15 pages, 8 figures, submitted to Phys. Rev.

Field Performance Of Domestic Heat Pumps For Heating And Hot Water In Switzerland Part I: Technology, Methods And State Of The Art Of The Field Studies

carried out by the Heat Pump Test Center (WPZ) in Buchs SG, Switzerland. In the current study, heat pumps for hydronic heating systems in single family houses within Switzerland have been investigated since 2016. So far, over 20 air-source and geothermal heat pumps have been added to this governmental quality assurance program (Swiss Federal authority EnergieSchweiz). For each heat pump system, more than 40 measured variables are recorded at a time interval of 10 s with calibrated sensors with very low measurement uncertainty. The aim of this field study is to record the real heat pump system efficiency in operation and to draw comparisons with characteristic values from laboratory measurements and manufacturer data. The study presented, is divided into two parts. The first part that is entitled “Technology, Methods and State of the Art of the field studies” focuses on the procedure, system boundaries and measuring technology of past and current field studies at WPZ Buchs and provides an insight to the state of the art of field performance measurements of domestic heat pumps carried out in Switzerland. The second part is entitled “Results, Analysis and Optimization of current field studies” and concentrates on various measured figures and the improvement potential of the investigated heat pump systems. Compared to the former studies made in the 1990s and early 2000s, the measurement methodology and data acquisition have changed considerably to date. Nowadays, thanks to digitalization, much more data is available. Short sampling intervals are used to describe temporal processes in heat pump systems in detail, enabling an easier detection of defects such as heat losses and unwanted circulation. Thanks to carefully defined system boundaries like JAZ, WNG and SNG heat pump systems can be compared and optimized effectively. Great importance is attached to the measurement of temperature because of its major influence on the overall uncertainty. Therefore, temperature is measured with an uncertainty of ±0.1 K/±0.02 K (absolute/relative) using directly immersed PT-100 sensors and four wire technology. Together with the prior calibration of the whole measuring equipment in the laboratory, an overall uncertainty of the target values (COP, JAZ) of 10% was achieved

Field Performance Of Domestic Heat Pumps For Heating And Hot Water In Switzerland Part II: Results, Analysis And Optimization

This study presents the development, the methods, and the state of the art of heat pump field trials as they are currently carried out by the Heat Pump Test Center (WPZ) in Buchs SG, Switzerland. In the current study, heat pumps for hydronic heating systems in single family houses within Switzerland have been investigated since 2016. So far, over 20 air-source and geothermal heat pumps have been added to this governmental quality assurance program (Swiss Federal authority EnergieSchweiz). For each heat pump system, more than 40 measured variables are recorded at a time interval of 10 s using calibrated sensors with very low measurement uncertainty. The aim of this field study is to record the real system efficiency in operation and to draw comparisons with characteristic values from laboratory measurements and manufacturer data. The study presented is divided into two parts. The first part entitled “Technology, Methods and State of the Art of the field studies” focuses on the procedure and measuring technology of field studies performed at WPZ Buchs. The second part is entitled “Results, Analysis and Optimization of current field studies” and presents meaningful results of the current field study as well as identification and optimization of possible deficiencies in the planning, installation and handling of the investigated heat pump systems. Heat pumps installed in new and refurbished buildings have been investigated with different system boundaries. In terms of performance, the current study shows an average annual coefficient of performance (SPF) of 3.6 and a span from 3.5 to 3.7 for floor heating and domestic hot water production using air/water heat pumps. Geothermal heat pump systems reach an average annual coefficient of performance of almost 5. Although the systems are running quite satisfying overall, the results also show considerable differences between the systems as well as typical mistakes in the installation and handling of the heat pumps. A controller that does not work optimally in terms of application and consumption is a frequently found cause of decreased performance. After evaluating the baseline performance for two years, the systems are optimized to increase performance and avoid poor operation. The collected data is also used to better define guidelines for planner and installers

Calling patterns of Western purple-faced langurs (Mammalia: Primates: Cercopithecidea: Trachypitchecus vetulus nestor) in a degraded human landscape in Sri

Abstract The study of calling patterns is a useful non-invasive method for determining population densities and the taxonomic relationships of rare or cryptic animal species. The Western purple-faced langur Trachypithecus vetulus nestor, endemic to Sri Lanka's lowland rainforests, is severely impacted by forest fragmentation, with most remaining populations living almost completely in home gardens. Due to their shy nature, little is known about the behaviour of this subspecies; analysing the regular loud calls emitted by these langurs could allow for improvement of census techniques, clarification of their taxonomy, and an understanding of the impact of forest destruction on their behaviour. In 2007, we recorded the calling patterns of five male T. v. nestor at Talangama Wetlands. Time, duration, weather conditions, and stimulant of 253 calls were noted. Loud calls comprised three structural units: harsh barks, whoops and residuals. The average call contained 4 phrases and 3.8 residuals, was 38 seconds in length, had an average maximum frequency of 3.5 kHz, a formant frequency of 0.36 kHz, and a fundamental frequency of 0.2 kHz. Significant differences were found between individuals for the number of phrases and residuals within a call, two different phrase lengths, the formant frequency and the fundamental frequency. The earliest call occurred at 05:27 hrs, while the latest was made at 17:57 hrs. The greatest percentage of calls (73.5%) was heard in the morning (05:00-09:59 hrs), mostly stimulated by territorial battles with neighbouring troops. These results show that vocalisations can be used to distinguish individual males; as langurs are more often heard than seen, and most troops contain only a single adult male, vocalisations may be used to determine the number of troops in an area. Calls of this taxon also differed from the other subspecies, suggesting that they may be used to distinguish subspecies and their boundaries. Finally, calling behaviour differed from other subspecies. Deforestation may be a direct cause of different calling patterns. These baseline data form a valuable starting point for further studies of this Critically Endangered primate

Imaging tumour hypoxia with positron emission tomography.

Hypoxia, a hallmark of most solid tumours, is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. Given its prominent role in oncology, accurate detection of hypoxia is important, as it impacts on prognosis and could influence treatment planning. A variety of approaches have been explored over the years for detecting and monitoring changes in hypoxia in tumours, including biological markers and noninvasive imaging techniques. Positron emission tomography (PET) is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels. This review provides an overview of imaging hypoxia with PET, with an emphasis on the advantages and limitations of the currently available hypoxia radiotracers.Cancer Research UK (CRUK) funded the National Cancer Research Institute (NCRI) PET Research Working party to organise a meeting to discuss imaging cancer with hypoxia tracers and Positron Emission Tomography. IF was funded by CRUK and is also supported by the Chief Scientific Office. ALH is supported by CRUK and the Breast Cancer Research Foundation. RM is funded by NIHR Cambridge Biomedical Research Centre.This is the accepted manuscript. The final version is available from Nature Publishing at http://www.nature.com/bjc/journal/vaop/ncurrent/full/bjc2014610a.html

Frequency, course and correlates of alcohol use from adolescence to young adulthood in a Swiss community survey

BACKGROUND: Few studies have analyzed the frequency of alcohol use across time from adolescence to young adulthood and its outcome in young adulthood. A Swiss longitudinal multilevel assessment project using various measures of psychopathology and psychosocial variables allowed for the study of the frequency and correlates of alcohol use so that this developmental trajectory may be better understood. METHOD: Alcohol use was studied by a questionnaire in a cohort of N = 593 subjects who had been assessed at three times between adolescence and young adulthood within the Zurich Psychology and Psychopathology Study (ZAPPS). Other assessment included questionnaire data measuring emotional and behavioural problems, life events, coping style, self-related cognitions, perceived parenting style and school environment, and size and efficiency of the social network. RESULTS: The increase of alcohol use from early adolescence to young adulthood showed only a few sex-specific differences in terms of the amount of alcohol consumption and the motives to drink. In late adolescence and young adulthood, males had a higher amount of alcohol consumption and were more frequently looking for drunkenness and feeling high. Males also experienced more negative consequences of alcohol use. A subgroup of heavy or problem drinkers showed a large range of emotional and behavioural problems and further indicators of impaired psychosocial functioning both in late adolescence and young adulthood. CONCLUSION: This Swiss community survey documents that alcohol use is problematic in a sizeable proportion of youth and goes hand in hand with a large number of psychosocial problems