{Bis[2-(diphenyl­phosphino)eth­yl]phenyl­phosphine-κ3 P,P′,P′′}chloridoplatinium(II) hexa­fluoridophosphate

In the title compound, [PtCl(C34H33P3)]PF6, the PtII cation adopts a distorted square-planar PtClP3 geometry, arising from the P,P′,P′′-tridentate triphos ligand and a chloride ion. Four of the F atoms of the PF6 − anion are disordered over two sets of positions in a 0.614 (17):0.386 (17) ratio

Stochastic volatility and leverage effect

We prove that a wide class of correlated stochastic volatility models exactly measure an empirical fact in which past returns are anticorrelated with future volatilities: the so-called ``leverage effect''. This quantitative measure allows us to fully estimate all parameters involved and it will entail a deeper study on correlated stochastic volatility models with practical applications on option pricing and risk management.Comment: 4 pages, 2 figure

Generalized pricing formulas for stochastic volatility jump diffusion models applied to the exponential Vasicek model

Path integral techniques for the pricing of financial options are mostly based on models that can be recast in terms of a Fokker-Planck differential equation and that, consequently, neglect jumps and only describe drift and diffusion. We present a method to adapt formulas for both the path-integral propagators and the option prices themselves, so that jump processes are taken into account in conjunction with the usual drift and diffusion terms. In particular, we focus on stochastic volatility models, such as the exponential Vasicek model, and extend the pricing formulas and propagator of this model to incorporate jump diffusion with a given jump size distribution. This model is of importance to include non-Gaussian fluctuations beyond the Black-Scholes model, and moreover yields a lognormal distribution of the volatilities, in agreement with results from superstatistical analysis. The results obtained in the present formalism are checked with Monte Carlo simulations.Comment: 9 pages, 2 figures, 1 tabl

Values of natural and human-made wetlands: A meta-analysis

The values of goods and services provided by wetland ecosystems are examined through a meta-analysis of an expanded database of wetland value estimates and with a focus on human-made wetlands. This study extends and improves upon previous meta-analyses of the wetland valuation literature in terms of the number of observations, geographical coverage, wetland class and integrity, and the measurement of the effects of scarcity and anthropogenic pressure. We find that water quality improvement, nonconsumptive recreation, and provision of natural habitat and biodiversity are highly valued services. Substitution effects are observed through the negative correlation between values and abundance of other wetlands. Wetland values are found to increase with anthropogenic pressure. An extended metaregression model with cross effects shows that the valuation of specific services varies with the type of wetland producing them. Human-made wetlands are highly valued for biodiversity enhancement, water quality improvement, and flood control

Gender differences in health care use among the elderly population in areas of Norway and Finland. A cross-sectional analysis based on the HUNT study and the FINRISK Senior Survey

BACKGROUND: The aim of the study was to examine gender differences in the self-reported use of health care services by the elderly in rural and metropolitan areas of two Nordic countries with slightly different health care systems: Finland and Norway. METHODS: Population based, cross-sectional surveys conducted in Nord-Tröndelag Norway (1995–97) and in rural and metropolitan areas of Finland (1997) were employed. In the Norwegian data, a total of 7,919 individuals, aged 65–74 years old were included, and the Finnish data included 1,500 individuals. The outcome variables comprised whether participants had visited a general practitioner or a specialist, or had received hospital care or physiotherapy during the past 12 months. Gender differences in the use of health care services were analysed by multiple logistic regression, controlling for health status and socio-demographic characteristics. RESULTS: In Norway, elderly women visited a specialist or were hospitalised less often than men. In Finland, elderly women used all health care services except hospital care more often than men. In Norway, less frequent use of specialist care by women was not associated with self-reported health or chronic diseases. CONCLUSION: The findings revealed differences in self-reported use of secondary care among different genders in areas of Norway and Finland

Why Rice Farmers Don't Sail: Coastal Subsistence Traditions and Maritime Trends in Early China

The Lower Yangtze River Valley is a key region for the early development of rice farming and the emergence of wet rice paddy field systems. Subsistence evidence from Neolithic sites in this area highlights the importance of freshwater wetlands for both plant and animal food resources. Early Neolithic rice cultivators looked inland, especially to wetlands and nearby woodlands, for their main protein sources. Links to the sea among these Neolithic populations are notably scarce. Due to the high yields of wet rice, compared with other staple crops as well as dryland rice, the wetland rice focused subsistence strategy of the Lower Yangtze would have supported high, and increasing, local population densities. Paddy agriculture demands labor input and water management on a large scale, which would have stimulated and reinforced trends towards more complex societies, such as that represented by Liangzhu in the lower Yangtze region. Population growth could have been largely absorbed locally, suggesting that population packing, not migration, was the dominant trend. Other case studies of agricultural dispersal, for the Korean Peninsula and Japan further illustrate the lack of correlation between the spread of rice agriculture and wet rice cultivation. Although wet rice cultivation was a pull factor that drew local populations towards increased density and increased social complexity, it did not apparently push groups to migrate outwards. Instead, the transition from wetland to rain fed rice cultivation systems and/or the integration of rice with rain fed millet crops are much more likely to have driven the demographic dynamics that underpin early farmer migrations and crop dispersal