Numerical Methods for Unconstrained Minimization : An Integrated Computational Environment

This study discusses the methods, algorithms and implementation techniques involved in the computational solution of unconstrained minimization problem : min x ∈ Rn f : Rn −! R Where Rn denotes the n-dimensional Euclidean space. The main goal in this study was to implement an easy-to-use software package running in personal computers for unconstrained minimization of multidimensional functions. This software package includes C language implementations of six minimization methods (listed below), an user-interface for entering each minimization problem, and an interface to a general software system called MathematicaTM which is used for plotting the problem function and the minimization route. The following minimization methods are discussed here : - Parabolic interpolation in one-dimension - Downhill simplex method in multidimensions - Direction set method in multidimensions - Variable metric method in multidimensions - Conjugate gradients method in multidimensions - Modified steepest descent method in multidimensions The first part of this study discusses the theoretical background of the minimization algorithms to be implemented in the software package. The second part introduces the overall design of the minimization software and in greater detail describes the individual software modules, which, as a whole, implement the software package. The third part introduces the techniques for testing the minimization algorithms, describes the set of test problems, and discusses the test results

An integrated simulation model to evaluate national policies for the abatement of agricultural nutrients in the Baltic Sea

This study introduces a prototype model for evaluating policies to abate agricultural nutrients in the Baltic Sea from a Finnish national point of view. The stochastic simulation model integrates nutrient dynamics of nitrogen and phosphorus in the sea basins adjoining the Finnish coast, nutrient loads from land and other sources, benefits from nutrient abatement (in the form of recreation and other ecosystem services) and the costs of agricultural abatement activities. The aim of this study is to present the overall structure of the model and to demonstrate its potential using preliminary parameters

An integrated simulation model to evaluate national policies for the abatement of agricultural nutrients in the Baltic Sea

This study introduces a prototype model for evaluating policies to abate agricultural nutrients in the Baltic Sea from a Finnish national point of view. The stochastic simulation model integrates nutrient dynamics of nitrogen and phosphorus in the sea basins adjoining the Finnish coast, nutrient loads from land and other sources, benefits from nutrient abatement (in the form of recreation and other ecosystem services) and the costs of agricultural abatement activities. The aim of this study is to present the overall structure of the model and to demonstrate its potential using preliminary parameters. The model is made flexible for further improvements in all of its ecological and economic components. Results of a sensitivity analysis suggest that investments in reducing the nutrient runoff from arable land in Finland would become profitable only if Finland’s neighbors in the northern Baltic committed themselves to similar reductions. Environmental investments for improving water quality yield the highest returns for the Bothnian Bay and the Gulf of Finland, and smaller returns for the Bothnian Sea. In the Bothnian Bay, the abatement activities become profitable because the riverine loads from Finland represent a high proportion of the total nutrient loads. In the Gulf of Finland, this proportion is low, but the size of the coastal population benefiting from improved water quality is high.ecosystem services, nutrient abatement, Monte Carlo simulation, recreation, valuation, Environmental Economics and Policy, Research Methods/ Statistical Methods,

Finnish agriculture and rural industries 2007

The report consists of following topics: operating environment of agriculture, agricultural and food market, agricultural policy, economic situation of agriculture, agriculture and the environment, rural and regional policy, special topics: biogas etc

Secondary Organic Aerosol Formation from Healthy and Aphid-Stressed Scots Pine Emissions.

One barrier to predicting biogenic secondary organic aerosol (SOA) formation in a changing climate can be attributed to the complex nature of plant volatile emissions. Plant volatile emissions are dynamic over space and time, and change in response to environmental stressors. This study investigated SOA production from emissions of healthy and aphid-stressed Scots pine saplings via dark ozonolysis and photooxidation chemistry. Laboratory experiments using a batch reaction chamber were used to investigate SOA production from different plant volatile mixtures. The volatile mixture from healthy plants included monoterpenes, aromatics, and a small amount of sesquiterpenes. The biggest change in the volatile mixture for aphid-stressed plants was a large increase (from 1.4 to 7.9 ppb) in sesquiterpenes-particularly acyclic sesquiterpenes, such as the farnesene isomers. Acyclic sesquiterpenes had different effects on SOA production depending on the chemical mechanism. Farnesenes suppressed SOA formation from ozonolysis with a 9.7-14.6% SOA mass yield from healthy plant emissions and a 6.9-10.4% SOA mass yield from aphid-stressed plant emissions. Ozonolysis of volatile mixtures containing more farnesenes promoted fragmentation reactions, which produced higher volatility oxidation products. In contrast, plant volatile mixtures containing more farnesenes did not appreciably change SOA production from photooxidation. SOA mass yields ranged from 10.8 to 23.2% from healthy plant emissions and 17.8-26.8% for aphid-stressed plant emissions. This study highlights the potential importance of acyclic terpene chemistry in a future climate regime with an increased presence of plant stress volatiles

Northern Rivers GIG Phytobenthos Intercalibration Exercise

General issues associated with phytobenthos intercalibration exercises are addressed in the report on the CB GIG intercalibration exercise. The conclusions and recommendations listed in that report are all equally valid for the N GIG exercise. This section highlights a few points that are unique to the N GIG exercise. The CB GIG exercise involved 12 Member States; whilst the N GIG exercise is much smaller, with just four participants. An important implication is that the exercise has lower statistical power and it is not always clear if those MS that fall outside the ‘acceptable band’ do so because there are issues that those MS need to address or because the ‘acceptable band’ is itself based on a small (and potentially atypical sample). On the other hand, however, the ‘acceptable band’ should not be equated with ‘best practice’. MS that comply with the minimum requirements of the exercise are included in the acceptable band and the position of this band, therefore, reflects the consensus of those. This must affect how results from N GIG and other smaller intercalibration exercises are judged. In particular, a ‘Type 1 error’ (i.e. erroneous rejection of the [null] hypothesis that boundaries are the same) may lead to the conclusion that a MS needs to adjust boundaries when, in fact, the median value of the ICM (which anchors the acceptable band) is unlikely to be stable with such a small sample size. The approach adopted here was, therefore, to perform a suite of tests using different permutations of the statistical criteria and to make final judgements about the need (or otherwise) to adjust boundaries based on the weight of evidence. Whilst the CB GIG exercise evaluated two versions of the ICM (one based on the mean of component metrics, the other based on the minimum), the N GIG exercise used both versions. TISI-min favoured IE and UK, both of whose national metric was the TDI, which correlates more strongly with the nutrient-sensitive TI, whilst TISI-mean favoured FI and SE whose national metric was the IPS, which correlated more strongly with the SI. Whilst TISI-mean is not biased by a low value of one or other metric, TISI-min better embodies the ‘one out, all out’ principle used when comparing biological elements as part of status assessments. Three of the four MS taking part in this exercise were also involved in the CB GIG exercise. Boundaries calculated in this exercise are broadly consistent between the two exercises. For H/G, IE, SE and UK were all inside the acceptable band for the CB GIG exercise whilst, for N GIG, UK were inside whilst SE was above the acceptable band for TISI-min but inside for TISI-mean and IE was marginally below for TISI-mean. For G/M, UK and SE were inside the acceptable band whilst IE was above. For the N GIG exercise, IE and UK were inside the acceptable band on all occasions whilst SE was again above the acceptable band when TISI-min was used. In the case of IE, the relatively small size of the dataset plus the low number of poor quality sites may be responsible for the differences in regression equations. Whilst SE were above the acceptable band on two out of four occasions for each of H/G and G/M comparisons, it is only those MS that fall below the acceptable band that need to consider harmonisation. In this exercise, both IE and FI fell below the acceptable band on one out of four occasions, both were only marginally below the acceptable band on these occasions and we believe that there is no case for either MS to adjust their boundarie

Terpene Composition Complexity Controls Secondary Organic Aerosol Yields from Scots Pine Volatile Emissions

Secondary organic aerosol (SOA) impact climate by scattering and absorbing radiation and contributing to cloud formation. SOA models are based on studies of simplified chemical systems that do not account for the chemical complexity in the atmosphere. This study investigated SOA formation from a mixture of real Scots pine (Pinus sylvestris) emissions including a variety of monoterpenes and sesquiterpenes. SOA generation was characterized from different combinations of volatile compounds as the plant emissions were altered with an herbivore stress treatment. During active herbivore feeding, monoterpene and sesquiterpene emissions increased, but SOA mass yields decreased after accounting for absorption effects. SOA mass yields were controlled by sesquiterpene emissions in healthy plants. In contrast, SOA mass yields from stressed plant emissions were controlled by the specific blend of monoterpene emissions. Conservative estimates using a box model approach showed a 1.5- to 2.3-fold aerosol enhancement when the terpene complexity was taken into account. This enhancement was relative to the commonly used model monoterpene, "alpha-pinene". These results suggest that simplifying terpene complexity in SOA models could lead to underpredictions in aerosol mass loading.Peer reviewe

The effect of bone marrow microenvironment on the functional properties of the therapeutic bone marrow-derived cells in patients with acute myocardial infarction

<p>Abstract</p> <p>Background</p> <p>Treatment of acute myocardial infarction with stem cell transplantation has achieved beneficial effects in many clinical trials. The bone marrow microenvironment of ST-elevation myocardial infarction (STEMI) patients has never been studied even though myocardial infarction is known to cause an imbalance in the acid-base status of these patients. The aim of this study was to assess if the blood gas levels in the bone marrow of STEMI patients affect the characteristics of the bone marrow cells (BMCs) and, furthermore, do they influence the change in cardiac function after autologous BMC transplantation. The arterial, venous and bone marrow blood gas concentrations were also compared.</p> <p>Methods</p> <p>Blood gas analysis of the bone marrow aspirate and peripheral blood was performed for 27 STEMI patients receiving autologous stem cell therapy after percutaneous coronary intervention. Cells from the bone marrow aspirate were further cultured and the bone marrow mesenchymal stem cell (MSC) proliferation rate was determined by MTT assay and the MSC osteogenic differentiation capacity by alkaline phosphatase (ALP) activity assay. All the patients underwent a 2D-echocardiography at baseline and 4 months after STEMI.</p> <p>Results</p> <p>As expected, the levels of pO₂, pCO₂, base excess and HCO₃were similar in venous blood and bone marrow. Surprisingly, bone marrow showed significantly lower pH and Na⁺and elevated K⁺levels compared to arterial and venous blood. There was a positive correlation between the bone marrow pCO₂and HCO₃levels and MSC osteogenic differentiation capacity. In contrast, bone marrow pCO₂and HCO₃levels displayed a negative correlation with the proliferation rate of MSCs. Patients with the HCO₃level below the median value exhibited a more marked change in LVEF after BMC treatment than patients with HCO₃level above the median (11.13 ± 8.07% vs. 2.67 ± 11.89%, P = 0.014).</p> <p>Conclusions</p> <p>Low bone marrow pCO₂and HCO₃levels may represent the optimal environment for BMCs in terms of their efficacy in autologous stem cell therapy in STEMI patients.</p