High Prevalence of Lifestyle Factors Attributable for Oral Cancer, and of Oral Potentially Malignant Disorders in Rural Sri Lanka

Background: Oral Cancer is a major public health problem in most of the South East Asian countries including Sri Lanka. Use of tobacco in the form of smokeless tobacco and smoking, use of alcohol and betel quid chewing are the major contributory factors for causation oral cancer. The aim of this study was to investigate the prevalence of lifestyle factors responsible for causation of oral cancer and Oral Potentially Malignant Disorders (OPMD) in the Sabaragamuwa province of Sri Lanka. Methods: A cross-sectional community based study was conducted in Sabaragamuwa province by interviewing, then conducting an oral examination, on 1029 subjects over 30 years of age, over a one year period from November 2006. The study protocol included an interviewer-administered questionnaire to gather socio-demographic factors, recording of habits that included areca/betel chewing, smoking, and alcohol consumption. A three-day food diary was obtained, particularly to assess the consumption of tea, fruits and vegetables. The weight and height of residents was taken for calculation of Body Mass Index (BMI). Results: One hundred and two individuals with one or more OPMD were detected among these 1029 subjects. The prevalence of OPMD, weighted according to the estate sector and gender, was estimated as 11.3%. The prevalence of daily betel quid chewing in this study was 53.8%: 15.7% without tobacco and 47.4% with tobacco. The prevalence of individuals who reported consumption of alcohol at least weekly was 13.4%. A significant minority, 31.7%, were under nourished, with a BMI < 18.5. Forty six percent of the males practiced combined habits of betel quid chewing, smoking and regular use of alcohol. Conclusions: This study discloses high prevalence of OPMD and of lifestyle factors for oral cancer in these communities. There is an urgent need for a comprehensive strategy to control the use of tobacco, betel quid chewing and alcohol for prevention of oral cancer.Full Tex

Challenges and opportunities for integrating lake ecosystem modelling approaches

A large number and wide variety of lake ecosystem models have been developed and published during the past four decades. We identify two challenges for making further progress in this field. One such challenge is to avoid developing more models largely following the concept of others (‘reinventing the wheel’). The other challenge is to avoid focusing on only one type of model, while ignoring new and diverse approaches that have become available (‘having tunnel vision’). In this paper, we aim at improving the awareness of existing models and knowledge of concurrent approaches in lake ecosystem modelling, without covering all possible model tools and avenues. First, we present a broad variety of modelling approaches. To illustrate these approaches, we give brief descriptions of rather arbitrarily selected sets of specific models. We deal with static models (steady state and regression models), complex dynamic models (CAEDYM, CE-QUAL-W2, Delft 3D-ECO, LakeMab, LakeWeb, MyLake, PCLake, PROTECH, SALMO), structurally dynamic models and minimal dynamic models. We also discuss a group of approaches that could all be classified as individual based: super-individual models (Piscator, Charisma), physiologically structured models, stage-structured models and trait-based models. We briefly mention genetic algorithms, neural networks, Kalman filters and fuzzy logic. Thereafter, we zoom in, as an in-depth example, on the multi-decadal development and application of the lake ecosystem model PCLake and related models (PCLake Metamodel, Lake Shira Model, IPH-TRIM3D-PCLake). In the discussion, we argue that while the historical development of each approach and model is understandable given its ‘leading principle’, there are many opportunities for combining approaches. We take the point of view that a single ‘right’ approach does not exist and should not be strived for. Instead, multiple modelling approaches, applied concurrently to a given problem, can help develop an integrative view on the functioning of lake ecosystems. We end with a set of specific recommendations that may be of help in the further development of lake ecosystem model

Impacts of climate warming on the long-term dynamics of key fish species in 24 European lakes

Fish play a key role in the trophic dynamics of lakes. With climate warming, complex changes in fish assemblage structure may be expected owing to direct effects of temperature and indirect effects operating through eutrophication, water level changes, stratification and salinisation. We reviewed published and new long-term (10–100 years) fish data series from 24 European lakes (area: 0.04–5,648 km2; mean depth: 1–177 m; a north–south gradient from Sweden to Spain). Along with an annual temperature increase of about 0.15–0.3°C per decade profound changes have occurred in either fish assemblage composition, body size and/or age structure during recent decades and a shift towards higher dominance of eurythermal species. These shifts have occurred despite a reduction in nutrient loading in many of the lakes that should have benefited the larger-sized individuals and the fish species typically inhabiting cold-water, low-nutrient lakes. The cold-stenothermic Arctic charr has been particularly affected and its abundance has decreased in the majority of the lakes where its presence was recorded. The harvest of cool-stenothermal brown trout has decreased substantially in two southern lakes. Vendace, whitefish and smelt show a different response depending on lake depth and latitude. Perch has apparently been stimulated in the north, with stronger year classes in warm years, but its abundance has declined in the southern Lake Maggiore, Italy. Where introduced, roach seems to take advantage of the higher temperature after years of low population densities. Eurythermal species such as common bream, pike–perch and/or shad are apparently on the increase in several of the lakes. The response of fish to the warming has been surprisingly strong and fast in recent decades, making them ideal sentinels for detecting and documenting climate-induced modifications of freshwater ecosystems