Influence of sampling frequency on the estimates of runoff water quality

Tiivistelmä: Havaintotiheyden vaikutus valumavesien laatuarvioihin

Noninvasive biomarkers for early smoking related lung disease

Chronic obstructive pulmonary disease (COPD) is a slowly progressive disease characterized by airway inflammation and largely irreversible airflow limitation. One major risk factor for COPD is cigarette smoking. Since the inflammatory process starts many years prior to the onset of clinical symptoms and still continues after smoking cessation, there is an urgent need to find simple non-invasive biomarkers that can be used in the early diagnosis of COPD and which could help in predicting the disease progression. The first aim of the present study was to evaluate the involvement of different oxidative/nitrosative stress markers, matrix metalloproteinases (MMPs) and their tissue inhibitor-1 (TIMP-1) in smokers and in COPD. Elevated numbers of inducible nitric oxide synthase (iNOS), nitrotyrosine, myeloperoxidase (MPO) and 4-hydroxy-2-nonenal (4-HNE) positive cells and increased levels of 8-isoprostane and lactoferrin were found in sputum of non-symptomatic smokers compared to non-smokers, and especially in subjects with stable mild to moderate COPD, and they correlated with the severity of airway obstruction. This suggests that an increased oxidant burden exists already in the airways of smokers with normal lung function values. However, none of these markers could differentiate healthy smokers from symptomatic smokers with normal lung function values i.e. those individuals who are at risk of developing COPD. In contrast what is known about asthma exhaled nitric oxide (FENO) was lower in smokers than in non-smokers, the reduced FENO value was significantly associated with neutrophilic inflammation and the elevated oxidant burden (positive cells for iNOS, nitrotyrosine and MPO). The levels of sputum MMP-8 and plasma MMP-12 appeared to differentiate subjects who have a risk for COPD development but these finding require further investigations. The levels of all studied MMPs correlated with the numbers of neutrophils, and MMP-8 and MMP-9 with markers of neutrophil activation (MPO, lactoferrin) suggesting that especially neutrophil derived oxidants may stimulate the tissue destructive MMPs already in lungs of smokers who are not yet experiencing any airflow limitation. When investigating the role of neutrophil proteases (neutrophil elastase, MMP-8, MMP-9) during COPD exacerbation and its recovery period, we found that levels of all these proteases were increased in sputum of patients with COPD exacerbation as compared to stable COPD and controls, and decreased during the one-month recovery period, giving evidence for a role of these enzymes in COPD exacerbations. In the last study, the effects of subject`s age and smoking habits were evaluated on the plasma levels of surfactant protein A (SP-A), SP-D, MMP-9 and TIMP-1. Long-term smoking increased the levels of all of these proteins. SP-A most clearly correlated with age, pack years and lung function decline (FEV1/FVC), and based on the receiver operating characteristic curve analysis, SP-A was the best marker for discriminating subjects with COPD from controls. In conclusion, these findings support the hypothesis that especially neutrophil derived oxidants may activate MMPs and induce an active remodeling process already in the lungs of smokers with normal lung function values. The marked increase of sputum levels of neutrophil proteases in smokers, stable COPD and/or during its exacerbations suggest that these enzymes play a role in the development and progression of COPD. Based on the comparison of various biomarkers, SP-A can be proposed to serve as sensitive biomarker in COPD development.

Early Growth and Later Health, Focus on Metabolic Syndrome, Obesity and Physical Activity

The Developmental Origins of Health and Disease Hypothesis proposes that adverse health outcomes in adult life are in part programmed during fetal life and infancy. This means that e.g. restricted nutrition during pregnancy programmes the offspring to store fat more effectively, to develop faster and to reach puberty earlier. These adaptations are beneficial in terms of short term survival. However, in developed countries these adaptations often lead to an increased risk of obesity and metabolic disturbances in later life, due to a mismatch between the prenatal and postnatal environment. This thesis aimed to study the role of early growth in people who are obese as adults, but metabolically healthy as well as in those who are normal in weight but metabolically obese. Other study aims were to assess whether physical activity and cardiorespiratory fitness are programmed early in life. The role of socioeconomic status in the development of obesity from a life course setting was also studied. These studies included 2003 men and women born in Helsinki between 1934 and 1944 with detailed information of their prenatal and childhood growth as well as living conditions. They participated in the detailed clinical examination during the years 2001-2004. A sub-group of the subjects participated in the UKK Institute 2-kilometre walk test. Metabolic syndrome was defined according to the 2005 criteria of the International Diabetes Federation. Among the obese men and women 20 % were metabolically healthy. Those with metabolic syndrome did not differ in birth size compared to the healthy ones, but by two years of age, they were lighter and thinner, and remained so up to 11 years. The period when changes in BMIs were predictive of the metabolic syndrome was from birth to 7 years. Of the normal weight individuals 17 % were metabolically obese. Again, there were no differences in birth size. However, by the age 7 years, those men who later developed metabolic syndrome were thinner. Gains in BMI during the first two years of life were protective of the syndrome. Children who were heavier, and especially taller, were more physically active, exercised with higher intensity and had higher cardiorespiratory fitness in their adult life than those who were shorter and thinner as children. Lower educational attainment and lower adult social class were associated with obesity in both men and women. Childhood social class was inversely associated with body mass index only in men while lower household income was associated with higher BMI in women. These results support the role of early life factors in the development of metabolic syndrome and adult life style. Early detection of risk factors predisposing to these conditions is highly relevant from a public health point of view.

A Sub-Nyquist Sampling Method For Computing The Level-crossing-times Of An Analog Signal: Theory And Applications

We address the problem of computing the level-crossings of an analog signal from samples measured on a uniform grid. Such a problem is important, for example, in multilevel analog-to-digital (A/D) converters. The first operation in such sampling modalities is a comparator, which gives rise to a bilevel waveform. Since bilevel signals are not bandlimited, measuring the level-crossing times exactly becomes impractical within the conventional framework of Shannon sampling. In this paper, we propose a novel sub-Nyquist sampling technique for making measurements on a uniform grid and thereby for exactly computing the level-crossing times from those samples. The computational complexity of the technique is low and comprises simple arithmetic operations. We also present a finite-rate-of-innovation sampling perspective of the proposed approach and also show how exponential splines fit in naturally into the proposed sampling framework. We also discuss some concrete practical applications of the sampling technique.

An Efficient Random Walk Strategy for Sampling Based Robot Motion Planners

Sampling based planners have been successful in path planning of robots with many degrees of freedom, but still remains ineffective when the configuration space has a narrow passage. We present a new technique based on a random walk strategy to generate samples in narrow regions quickly, thus improving efficiency of Probabilistic Roadmap Planners. The algorithm substantially reduces instances of collision checking and thereby decreases computational time. The method is powerful even for cases where the structure of the narrow passage is not known, thus giving significant improvement over other known methods.

Electronic structure of early 3d-transition-metal oxides by analysis of the 2p core-level photoemission spectra

The electronic structures of a wide range of early transition-metal (TM) compounds, including Ti and V oxides with metal valences ranging from 2+ to 5+ and formal d-electron numbers ranging from 0 to 2, have been investigated by a configuration-interaction cluster model analysis of the core-level metal 2p x-ray photoemission spectra (XPS). Inelastic energy-loss backgrounds calculated from experimentally measured electron-energy-loss spectra (EELS) were subtracted from the XPS spectra to remove extrinsic loss features. Parameter values deduced for the charge-transfer energy Delta and the d-d Coulomb repulsion energy U are shown to continue the systematic trends established previously for the late TM compounds, giving support to a charge-transfer mechanism for the satellite structures. The early TM compounds are characterized by a large metal d-ligand p hybridization energy, resulting in strong covalency in these compounds. Values for Delta and U suggest that many early TM compounds should be reclassified as intermediate between the charge-transfer regime and the Mott-Hubbard regime.

Recovery of tropical rainforest avifauna in relation to vegetation succession following shifting cultivation in Mizoram, north-east India

1. Recovery of rainforest bird community structure and composition, in relation to forest succession after slash-and-burn shifting cultivation or jhum was studied in Mizoram, north-east India. Replicate fallow sites abandoned after shifting cultivation 1, 5, 10, 25 and approximate to 100 years ago, were compared with primary evergreen and semi-evergreen forest using transect and quadrat sampling. 2. Vegetation variables such as woody plant species richness, tree density and vertical stratification increased with fallow age in a rapid. nun-linear, asymptotic manner. Principal components analysis of vegetation variables summarized 92.8% of the variation into two axes: PC1 reflecting forest development and woody plant succession (variables such as tree density, woody plant species richness), and PC2 depicting bamboo density, which increased from 1 to 25 years and declined thereafter. 3. Bird species richness, abundance and diversity, increased rapidly and asymptotically during succession paralleling vegetation recovery as shown by positive correlations with fallow age and PC1 scores of sites. Bamboo density reflected by PC2 had a negative effect on bird species richness and abundance. 4. The bird community similarity (Morisita index) of sites with primary forest also increased asymptotically with fallow age indicating sequential species turnover during succession. Bird community similarity of sites with primary forest (or between sites) was positively correlated with both physiognomic and floristic similarities with primary forest (or between sites). 5. The number of bird species in guilds associated with forest development and woody plants (canopy insectivores, frugivores: bark feeders) was correlated with PCI scores of the sites. Species in other guilds (e. g. granivores, understorey insectivores) appeared to dominate during early and mid-succession. 6. The non-linear relationships imply that fallow periods less than a threshold of 25 years for birds, and about 50-75 years for woody plants, are likely to cause substantial community alteration. 7. As 5-10-year rotation periods or jhum cycles prevail in many parts of north-east India. there is a need to protect and conserve tracts of late-successional and primary forest.

Nucleation and growth characteristics of cavities during the early stages of tensile creep deformation in a superplastic zirconia-20 wt% alumina composite

Constant-stress tensile creep experiments on a superplastic 3-mol%-yttria-stabilized tetragonal zirconia composite with 20 wt% alumina revealed that cavities nucleate relatively early during tensile deformation. The number of cavities nucleated increases with increasing imposed stress. The cavities nucleate at triple points associated largely with an alumina grain, and then grow rapidly in a cracklike manner to attain dimensions on the order of the grain facet size. It is suggested that coarser-grained superplastic ceramics exhibit lower ductility due to the ease in formation of such grain boundary facet-cracks and their interlinkage to form a macroscopic crack of critical dimensions.

Profiling of late Tertiary-early Quaternary surface in the lower reaches of Narmada valley using microtremors

In this paper, we propose the first approximation for thickness of Quaternary sediment and late Quaternary early Tertiary topography for the part of lower reaches of Narmada valley in a systematic way using the shallow seismic method, that records both horizontal and vertical components of the microtremor (ambient noise) caused by natural processes. The measurements of microtremors were carried out at 31 sites spaced at a grid interval of 5 km s using Lennartz seismometer (5 s period) and City shark-II data acquisition system. The signals recorded were analysed for horizontal to the vertical (H/V) spectral ratio using GEOPSY software. For the present study, we concentrate on frequency range between 0.2 Hz and 10 Hz. The thickness of unconsolidated sediments at various sites is calculated based on non-linear regression equations proposed by Ibs-von Seht and Wohlenberg (1999) and Parolai et al. (2002). The estimated thickness is used to plot digital elevation model and cross profiles correlating with geomorphology and geology of the study area. (C) 2011 Elsevier Ltd. All rights reserved.

Tidally compressed gas in centers of early-type and ultraluminous galaxies

In this paper we propose that the compressive tidal held in the centers of flat-core early-type galaxies and ultraluminous galaxies compresses molecular clouds producing dense gas observed in the centers of these galaxies. The effect of galactic tidal fields is usually considered disruptive in the literature. However, for some galaxies, the mass profile flattens toward the center and the resulting galactic tidal field is not disruptive, but instead it is compressive within the flat-core region. We have used the virial theorem to determine the minimum density of a molecular cloud to be stable and gravitationally bound within the tidally compressive region of a galaxy. We have applied the mechanism to determine the mean molecular cloud densities in the centers of a sample of flat-core, early-type galaxies and ultraluminous galaxies. For early-type galaxies with a core-type luminosity profile, the tidal held of the galaxy is compressive within half the core radius. We have calculated the mean gas densities for molecular gas in a sample of early-type galaxies which have already been detected in CO emission, and we obtain mean densities of [n] similar to 10(3)-10(6) cm(-3) within the central 100 pc radius. We also use our model to calculate the molecular cloud densities in the inner few hundred parsecs of a sample of ultraluminous galaxies. From the observed rotation curves of these galaxies we show that they have a compressive core within their nuclear region. Our model predicts minimum molecular gas densities in the range 10(2)-10(4) cm(-3) in the nuclear gas disks; the smaller values are applicable typically for galaxies with larger core radii. The resulting density values agree well with the observed range. Also, for large core radii, even fairly low-density gas (similar to 10(2) cm(-3)) can remain bound and stable close to the galactic center.

Geochemistry of water and ground water in the Nhecolandia, Pantanal of Mato Grosso, Brazil: Variability and associated processes

A distinctive feature of the Nhecolandia, a sub-region of the Pantanal wetland in Brazil, is the presence of both saline and freshwater lakes. Saline lakes used to be attributed to a past and phase during the Pleistocene. However, recent studies have shown that saline and fresh water lakes are linked by a continuous water table, indicating that saline water could come from a contemporary concentration process. This concentration process could also be responsible for the large chemical variability of the waters observed in the area. A regional water sampling has been conducted in surface and sub-surface water and the water table, and the results of the geochemical and statistical analysis are presented. Based on sodium contents, the concentration shows a 1: 4443 ratio. All the samples belong to the same chemical family and evolve in a sodic alkaline manner. Calcite or magnesian calcite precipitates very early in the process of concentration, probably followed by the precipitation of magnesian silicates. The most concentrated solutions remain under-saturated with respect to the sodium carbonate salt, even if this equilibrium is likely reached around the saline lakes. Apparently, significant amounts of sulfate and chloride are lost simultaneously from the solutions, and this cannot be explained solely by evaporative concentration. This could be attributed to the sorption on reduced minerals in a green sub-surface horizon in the "cordilhieira" areas. In the saline lakes, low potassium, phosphate, magnesium, and sulfate are attributed to algal blooms. Under the influence of evaporation, the concentration of solutions and associated chemical precipitations are identified as the main factors responsible for the geochemical variability in this environment (about 92 % of the variance). Therefore, the saline lakes of Nhecolandia have to be managed as landscape units in equilibrium with the present water flows and not inherited from a past and phase. In order to elaborate hydrochemical tracers for a quantitative estimation of water flows, three points have to be investigated more precisely: (1) the quantification of magnesium involved in the Mg-calcite precipitation; (2) the identification of the precise stoichiometry of the Mg-silicate; and (3) the verification of the loss of chloride and sulfate by sorption onto labile iron minerals.

Performance analysis of the random early detection algorithm

In this article we consider a finite queue with its arrivals controlled by the random early detection algorithm. This is one of the most prominent congestion avoidance schemes in the Internet routers. The aggregate arrival stream from the population of transmission control protocol sources is locally considered stationary renewal or Markov modulated Poisson process with general packet length distribution. We study the exact dynamics of this queue and provide the stability and the rates of convergence to the stationary distribution and obtain the packet loss probability and the waiting time distribution. Then we extend these results to a two traffic class case with each arrival stream renewal. However, computing the performance indices for this system becomes computationally prohibitive. Thus, in the latter half of the article, we approximate the dynamics of the average queue length process asymptotically via an ordinary differential equation. We estimate the error term via a diffusion approximation. We use these results to obtain approximate transient and stationary performance of the system. Finally, we provide some computational examples to show the accuracy of these approximations.