A Simple Five-Level Inverter Topology for Induction Motor Drive Using Conventional Two-Level Inverters and Flying Capacitor Technique

This paper proposes a new five-level inverter topology for open-end winding induction motor (IM) drive. The popular existing circuit configurations for five-level inverter include the NPC inverter and flying capacitor topologies. Compared to the NPC inverter, the proposed topology eliminates eighteen clamping diodes having different voltage ratings in the present circuit. Moreover it requires only one capacitor bank per phase, whereas flying capacitor schemes for five level topologies require six capacitor banks per phase. The proposed topology is realized by feeding the phase winding of an open-end induction motor with two-level inverters in series with flying capacitors. The flying capacitor voltages are balanced using the switching state redundancy for full modulation range. The proposed inverter scheme is capable of producing two-level to five-level pulse width modulated voltage across the phase winding depending on the modulation range. Additionally, in case of any switch failure in the flying capacitor connection, the proposed inverter topology can be operated as a three-level inverter for full modulation range. The proposed scheme is experimentally verified on a four pole, 5hp induction motor drive.

Electronic structure of high-Tc superconductors from core-level spectroscopies

Using the configuration-interaction approach, we show that various core-level spectroscopic observations on the high-Tc superconducting oxides can be consistently described in terms of mixing between d9 and d10 configurations, with a negligible amount of the d8 (Cu3+) state. From our analysis of the existing experimental data, we provide evidence of a wide and continuous valence transition in these systems as a function of temperature. The changes in the hybridization strengths deduced here are indicative of structural modifications of the square-planar CuO4 clusters with decreasing temperature.

Vitamin A and thyroxine carrier proteins in chicken plasma Steady-state control of the plasma level of free retinol-binding protein and free thyroxine

1. 1. The binding parameters of prealbumin-2 with retinol-binding protein and thyroxine (T4) revealed the existence of distinct and multiple sites for both retinol-binding protein and T4. 2. 2. From the analysis of binding parameters of retinol-binding protein with prealbumin-2 it is clear that under steady-state conditions about 99% of the holo-retinol-binding protein remains bound to prealbumin-2. 3. 3. Equilibrium dialysis studies on binding properties of thyroid hormones with prealbumin-2 revealed that it has a single high affinity site and three low affinity sites. 4. 4. The occurrence of three carrier proteins for thyroid hormones, thyroxine-binding globulin, prealbumin-2 and albumin has been demonstrated. However, the chicken thyroxine-binding globulin differs from human thyroxine-binding globulin by being relatively less acidic and occuring at a two-fold lower concentration. But the thyroid hormone binding parameters are comparable. 5. 5. Highly sensitive methods were developed for determination of T4 binding capacities of the various proteins and plasma level of total T4 by fractionation of carrier proteins and further quantitatively employing in electrophoresis and equilibrium dialysis. 6. 6. The thyroxine-binding proteins were found to be two types, one (viz., thyroxine-binding globulin) of great affinity but of low binding capacity, which mainly acts as reservoir of T4, and another (viz.,prealbumin-2) of low affinity but of high binding capacity, which can participate predominantly in the control of the free T4 pool.

"Miksi lehmät pitää tappaa?" : Etnografinen tutkimus 2000-luvun alun huumemarkkinoista Helsingissä

The present study focuses on the drug market in Helsinki in the early 2000s, mainly on the dealing in and use of amphetamines, cannabis and the pharmaceutical Subutex. The drug market is usually analysed into upper, middle and lower level markets. These levels are very different in terms of their operating practices, although there may be some mingling. The present study is mainly concerned with drug dealers and users in the lower and middle level markets. Operations also differ depending on whether the dealing involves just one drug or several. Dealing in and using Subutex is a very different business from dealing and using home grown cannabis, for instance: both the customers and the dealers are mostly quite different. The study material was mostly collected through ethnographical field work, including observations and interviews. Interviews with officials and minutes of pre-trial investigations concerning aggravated drug crimes are also included. The study discusses the roles of dealers on the various levels of the drug market in Helsinki and traces activities at various levels. Ethnographical methods are employed to observe day-to-day drug dealing and use and leisure pursuits in private homes and in public premises. The study takes note of the risks inherent in drug dealing and estimates what kind of drug dealers can last the longest on the market without the authorities intervening. At the same time, the study discusses how small groups on the middle and lower levels of the drug market avoid control measures undertaken by the authorities and how the authorities address these groups. Moreover, the study discusses what the drug market is like in prison from the perspective of a drug dealer sent to prison, what their everyday lives are like after release, and how much money dealers on various levels of the drug market make. The study demonstrates that drug dealing in Helsinki, whether we consider the very top or the very bottom of the pyramid, is a far from rational pursuit. The undertakings are not very systematic; they are more a reaction to intoxicant addiction( s) and other problems caused by other dealers, the dealers own actions and the actions of the police. The everyday lives of drug dealers are often chaos only alleviated by drug use in the company of buyers or alone. If a drug dealer uses drugs himself/herself, things become even more complicated and a vicious circle develops. At the same time, everyday life is certainly exciting, and a drug dealer often has a highly eventful if brief life. Drug dealing is a very masculine pursuit, and there is a sort of macho code governing it, although this does not nearly always work as it should. This macho code, typically for illegal activities, involves the threat of violence as a control measure. Hence the untranslatable slang expression Kill the cows : the Finnish word for calf has the slang meaning snitch or police informant . No more cows, no more calves. But informing on others to the authorities is a fact of life in the drug-dealing world. Contributing factors to being reported to the authorities are the dealer s own mistakes and the actions of other dealers and the police. A determined drug dealer will not be deterred from drug dealing by a prison sentence. However, following time in prison only few dealers manage to gain an income from drug dealing commensurate with its risks.

Puunoston kehittäminen Stora Enso Metsän Helsingin palvelupisteessä

The operation environment in the roundwood trade in Finland in the 1990’s include several changes. They are changes in the structure of non-industrial private forest (NIPF) ownership, forest taxation, in forest legislation, in price recommendation agreement, diminishing resources of forestry extension services, etc. At the same time, the roundwood demand has been rising. All these developments cause uncertainty in wood procurement organisations, and call for research to find out how to adapt into the changing environment. The objective of this study is to produce information for roundwood purchasing planning and cus-tomer satisfaction management to be used by Stora Enso Metsä Customer Service, Helsinki. For this pur-pose, data needs to be gathered about the urban NIPFs and their forest estates, behaviour related to forestry and timber-selling, customer satisfaction in their latest timber selling transaction, and their opinions about Enso’s new customer service office and its service concept. To fulfil the objective of the study, a NIPF -owner -survey (N=1064, response rate 39,7%) was con-ducted in October 1998-January 1999. The sample was made on the basis of the marketing database of Stora Enso Oyj Forest Customer Service in Helsinki. In planning the frame of reference of the empirical study, the model of service quality by Grönroos was applied. The following aspects were included in the 7-page questionnaire: demographic, sosio-economic and forest estate background, relation to the forest service supply, behaviour related to forestry, timber-selling motives and behaviour, last contact organisation and its image in forestry business, expectations and percep-tions in the latest timber-selling transactions, and behavioural intentions. The results revealed that the share of women, pensioners and academically educated people among forest owners was quite high. The majority of the forest estates of the metropolitan forest owners were situ-ated in the provinces of South Finland and East Finland. The average forest estate area was considerably smaller than in a previous study. Economic and recreational objectives were most important in the use of forests. Forest Associations were involved in half of the roundwood sales transactions of the respondents in the metropolitan area. The wood quantity of transactions was considerably higher than the average in the whole country. Bank-organised forest-related activities, taxation infos and trips to the forest were the most popular activities. Among the services, silvicultural advices were needed mostly and stub treatment least. Brochure material related to stumpage timber sales and taxation were considered most important compared to material related to delivery sales. The service expectations were at highest for women and they were less satisfied with the service than men. 2nd and 3rd generation residents of the metropolitan area thought about the new customer service concept more positively than the 1st generation residents. Internet users under 60 years thought more positively about new satellite picture-based woodlot search concept. Cross-tabulation of factor scores against background variables indicated that women with relatively low education level a greater need to sell roundwood than entrepreneurs, white-collar workers and directors, and Internet users. Suspiciousness towards timber procurement organisations was relatively strong among women and those whose forest income share of the total income was either null or over 20 %. The average customer satisfaction score was negative in all nine questions. Statistical differences be-tween different companies did not exist in the average satisfaction scores. Stora Enso’s Helsinki forest cus-tomer service could choose the ability to purchase all timber grades as its competitive advantage. Out of nine service dimension included in the questionnaire, in this particular service dimension, Enso’s Helsinki forest customer service’s score exceeded most all organisations’ average customer satisfaction score. On the basis of importance – performance matrix, advice and quidance could have been provided more to the forest owners in their latest timber–selling transaction.

System effects in double‐channel gated‐integrator‐based deep‐level transient spectroscopy

The effects of the two sampling gate positions, and their widths and the integrator response times on the position, height, and shape of the peaks obtained in a double‐channel gated‐integrator‐based deep‐level transient spectroscopy (DLTS) system are evaluated. The best compromise between the sensitivity and the resolution of the DLTS system is shown to be obtained when the ratio of the two sampling gate positions is about 20. An integrator response time of about 100 ms is shown to be suitable for practical values of emission time constants and heating rates generally used.

Perinatal mortality and maternal health in rural China

Background and context Since the economic reforms of 1978, China has been acclaimed as a remarkable economy, achieving 9% annual growth per head for more than 25 years. However, China's health sector has not fared well. The population health gains slowed down and health disparities increased. In the field of health and health care, significant progress in maternal care has been achieved. However, there still remain important disparities between the urban and rural areas and among the rural areas in terms of economic development. The excess female infant deaths and the rapidly increasing sex ratio at birth in the last decade aroused serious concerns among policy makers and scholars. Decentralization of the government administration and health sector reform impacts maternal care. Many studies using census data have been conducted to explore the determinants of a high sex ratio at birth, but no agreement has been so far reached on the possible contributing factors. No study using family planning system data has been conducted to explore perinatal mortality and sex ratio at birth and only few studies have examined the impact of the decentralization of government and health sector reforms on the provision and organization of maternal care in rural China. Objectives The general objective of this study was to investigate the state of perinatal health and maternal care and their determinants in rural China under the historic context of major socioeconomic reforms and the one child family planning policy. The specific objectives of the study included: 1) to study pregnancy outcomes and perinatal health and their correlates in a rural Chinese county; 2) to examine the issue of sex ratio at birth and its determinants in a rural Chinese county; 3) to explore the patterns of provision, utilization, and content of maternal care in a rural Chinese county; 4) to investigate the changes in the use of maternal care in China from 1991 to 2003. Materials and Methods This study is based on a project for evaluating the prenatal care programme in Dingyuan county in 1999-2003, Anhui province, China and a nationwide household health survey to describe the changes in maternal care utilization. The approaches used included a retrospective cohort study, cross sectional interview surveys, informant interviews, observations and the use of statistical data. The data sources included the following: 1) A cohort of pregnant women followed from pregnancy up to 7 days after birth in 20 townships in the study county, collecting information on pregnancy outcomes using family planning records; 2) A questionnaire interview survey given to women who gave birth between 2001 and 2003; 3) Various statistical and informant surveys data collected from the study county; 4) Three national household health interview survey data sets (1993-2003) were utilized, and reanalyzed to described the changes in maternity care utilization. Relative risks (RR) and their confidence intervals (CI) were calculated for comparison between parity, approval status, infant sex and township groups. The chi-square test was used to analyse the disparity of use of maternal care between and within urban and rural areas and its trend across the years in China. Logistic regression was used to analyse the factors associated with hospital delivery in rural areas. Results There were 3697 pregnancies in the study cohort, resulting in 3092 live births in a total population of 299463 in the 20 study townships during 1999-2000. The average age at pregnancy in the cohort was 25.9 years. Of the women, 61% were childless, 38% already had one child and 0.3% had two children before the current pregnancy. About 90% of approved pregnancies ended in a live birth while 73% of the unapproved ones were aborted. The perinatal mortality rate was 69 per thousand births. If the 30 induced abortions in which the gestational age was more than 28 weeks had been counted as perinatal deaths, the perinatal mortality rate would have been as high as 78 per thousand. The perinatal mortality rate was negatively associated with the wealth of the township. Approximately two thirds of the perinatal deaths occurred in the early neonatal period. Both the still birth rate and the early neonatal death rate increased with parity. The risk of a stillbirth in a second pregnancy was almost four times that for a first pregnancy, while the risk of early neonatal deaths doubled. The early neonatal mortality rate was twice as high for female as for male infants. The sex difference in the early neonatal mortality rate was mainly attributable to mortality in second births. The male early neonatal mortality rate was not affected by parity, while the female early neonatal mortality rate increased dramatically with parity: it was about six times higher for second births than for first births. About 82% early neonatal deaths happened within 24 hours after birth, and during that time, girls were almost three times more likely to die than boys. The death rate of females on the day of birth increased much more sharply with parity than that of males. The total sex ratio at birth of 3697 registered pregnancies was 152 males to 100 females, with 118 and 287 in first and second pregnancies, respectively. Among unapproved pregnancies, there were almost 5 live-born boys for each girl. Most prenatal and delivery care was to be taken care of in township hospitals. At the village level, there were small private clinics. There was no limitation period for the provision of prenatal and postnatal care by private practitioners. They were not permitted to provide delivery care by the county health bureau, but as some 12% of all births occurred either at home or at private clinics; some village health workers might have been involved. The county level hospitals served as the referral centers for the township hospitals in the county. However, there was no formal regulation or guideline on how the referral system should work. Whether or not a woman was referred to a higher level hospital depended on the individual midwife's professional judgment and on the clients' compliance. The county health bureau had little power over township hospitals, because township hospitals had in the decentralization process become directly accountable to the township government. In the township and county hospitals only 10-20% of the recurrent costs were funded by local government (the township hospital was funded by the township government and the county hospital was funded by the county government) and the hospitals collected user fees to balance their budgets. Also the staff salaries depended on fee incomes by the hospital. The hospitals could define the user charges themselves. Prenatal care consultations were however free in most township hospitals. None of the midwives made postnatal home visits, because of low profit of these services. The three national household health survey data showed that the proportion of women receiving their first prenatal visit within 12 weeks increased greatly from the early to middle 1990s in all areas except for large cities. The increase was much larger in the rural areas, reducing the urban-rural difference from more than 4 times to about 1.4 times. The proportion of women that received antenatal care visits meeting the Ministry of Health s standard (at least 5 times) in the rural areas increased sharply from 12% in 1991-1993 to 36% in 2001-2003. In rural areas, the proportion increase was much faster in less developed areas than in developed areas. The hospital delivery rate increased slightly from 90% to 94% in urban areas while the proportion increased from 27% to 69% in rural areas. The fastest change was found to be in type 4 rural areas, where the utilization even quadrupled. The overall difference between rural and urban areas was substantially narrowed over the period. Multiple logistic regression analysis shows that time periods, residency in rural or urban areas, income levels, age group, education levels, delivery history, occupation, health insurance and distance from the nearest health care facilities were significantly associated with hospital delivery rates. Conclusions 1. Perinatal mortality in this study was much higher than that for urban areas as well as any reported rate from specific studies in rural areas of China. Previous studies in which calculations of infant mortality were not based on epidemiological surveys have been shown to underestimate the rates by more than 50%. 2. Routine statistics collected by the Chinese family planning system proved to be a reliable data source for studying perinatal health, including still births, neonatal deaths, sex ratio at birth and among newborns. National Household Health Survey data proved to be a useful and reliable data source for studying population health and health services. Prior to this research there were few studies in these areas available to international audiences. 3.Though perinatal mortality rate was negatively associated with the level of township economic development, the excess female early neonatal mortality rate contributed much more to high perinatal mortality rate than economic factors. This was likely a result of the role of the family planning policy and the traditional preferences for sons, which leads to lethal neglect of female newborns and high perinatal mortality. 4. The selective abortions of female foetuses were likely to contribute most to the high sex ratio at birth. The underreporting of female births seemed to have played a secondary role. The higher early neonatal mortality rate in second-born as compared to first-born children, particularly in females, may indicate that neglect or poorer care of female newborn infants also contributes to the high sex ratio at birth or among newborns. Existing family planning policy proved not to effectively control the steadily increased birth sex ratio. 5. The rural-urban gap in service utilization was on average significantly narrowed in terms of maternal healthcare in China from 1991 to 2003. This demonstrates that significant achievements in reducing inequities can be made through a combination of socio-economic development and targeted investments in improving health services, including infrastructure, staff capacities, and subsidies to reduce the costs of service utilization for the poorest. However, the huge gap which persisted among cities of different size and within different types of rural areas indicated the need for further efforts to support the poorest areas. 6. Hospital delivery care in the study county was better accepted by women because most of women think delivery care was very important while prenatal and postnatal care were not. Hospital delivery care was more systematically provided and promoted than prenatal and postnatal care by township hospital in the study area. The reliance of hospital staff income on user fees gave the hospitals an incentive to put more emphasis on revenue generating activities such as delivery care instead of prenatal and postnatal care, since delivery care generated much profits than prenatal and postnatal care . Recommendations 1. It is essential for the central government to re-assess and modify existing family planning policies. In order to keep national sex balance, the existing practice of one couple one child in urban areas and at-least-one-son a couple in rural areas should be gradually changed to a two-children-a-couple policy throughout the country. The government should establish a favourable social security policy for couples, especially for rural couples who have only daughters, with particular emphasis on their pension and medical care insurance, combined with an educational campaign for equal rights for boys and girls in society. 2. There is currently no routine vital-statistics registration system in rural China. Using the findings of this study, the central government could set up a routine vital-statistics registration system using family planning routine work records, which could be used by policy makers and researchers. 3. It is possible for the central and provincial government to invest more in the less developed and poor rural areas to increase the access of pregnant women in these areas to maternal care services. Central government together with local government should gradually provide free maternal care including prenatal and postnatal as well as delivery care to the women in poor and less developed rural areas. 4. Future research could be done to explore if county and the township level health care sector and the family planning system could be merged to increase the effectiveness and efficiency of maternal and child care. 5. Future research could be done to explore the relative contribution of maternal care, economic development and family planning policy on perinatal and child health using prospective cohort studies and community based randomized trials. Key words: perinatal health, perinatal mortality, stillbirth, neonatal death, sex selective abortion, sex ratio at birth, family planning, son preference, maternal care, prenatal care, postnatal care, equity, China

A Five-Level Inverter Scheme for a Four-Pole Induction Motor Drive by Feeding the Identical Voltage-Profile Windings From Both Sides

This paper presents a five-level inverter scheme with four two-level inverters for a four-pole induction motor (IM) drive. In a conventional three-phase four-pole IM, there exists two identical voltage-profile winding coil groups per phase around the armature, which are connected in series and spatially apart by two pole pitches. In this paper, these two identical voltage-profile pole-pair winding coils in each phase of the IM are disconnected and fed from four two-level inverters from four sides of the windings with one-fourth dc-link voltage as compared to a conventional five-level neutral-point-clamped inverter. The scheme presented in this paper does not require any special design modification for the induction machine. For this paper, a four-pole IM drive is used, and the scheme can be easily extended to IMs with more than four poles. The proposed scheme is experimentally verified on a four-pole 5-hp IM drive.

Arrested Drunk Drivers : Trends, social background, recidivism and mortality

The aim of this study was to examine the trends, incidence and recidivism of drunken driving during a 20-year period (1988 - 2007) using the data on all suspected drunken driving in this period. Furthermore, the association between social background and drunken driving, and the mortality of drunk drivers were studied by using administrative register data provided by Statistics Finland. The study was completely register-based. In 1989 - 1991, every year 30,000 drivers were suspected of drunken driving, but the number fell to less than 20,000 by 1994, during the economic recession. The changes in the arrest incidence of the youngest age groups were especially pronounced, most of all in the age group of 18 - 19-year olds. Even though the incidence among youth decreased dramatically, their incidence rate was still twice that of the general population aged 15 - 84 years. Drunken driving was associated with a poor social background among youth and working-aged men and women. For example, a low level of education, unemployment, divorce, and parental factors in youth were associated with a higher risk of being arrested for drunken driving. While a low income was related to more drunken driving among working-aged people, the effect among young persons was the opposite. Every third drunk driver got rearrested during a 15-year period, whereas the estimated rearrest rate was 44%. Findings of drugs only or in combination with alcohol increased the risk of rearrest. The highest rearrest rates were seen among drivers who were under the influence of amphetamines or cannabis. Also male gender, young age, high blood alcohol concentration, and arrest during weekdays and in the daytime predicted rearrest. When compared to the general population, arrested drunk drivers had significant excess mortality. The greatest relative differences were seen in alcohol-related causes of death (including alcohol diseases and alcohol poisoning), accidents, suicides and violence. Also mortality due to other than alcohol-related diseases was elevated among drunk drivers. Drunken driving was associated with multiple factors linked to traffic safety, health and social problems. Social marginalization may expose a person to harmful use of alcohol and drunken driving, and the associations are seen already among the youth. Recidivism is common among drunk drivers, and driving under the influence of illicit and/or medicinal drugs is likely to indicate worse substance abuse problems, judging from the high rearrest rates. High alcohol-related mortality in this population shows that drunken driving is clearly an indicator of alcohol abuse. More effective measures of preventing alcohol-related harms are needed, than merely preventing convicted drunk drivers from driving again.

Do Households Have Rational Expectations on Future Consumption? Evidence from the Finnish Consumer Survey

Ever since its initial introduction some fifty years ago, the rational expectations paradigm has dominated the way economic theory handles uncertainty. The main assertion made by John F. Muth (1961), seen by many as the father of the paradigm, is that expectations of rational economic agents should essentially be equal to the predictions of relevant economic theory, since rational agents should use information available to them in an optimal way. This assumption often has important consequences on the results and interpretations of the models where it is applied. Although the rational expectations assumption can be applied to virtually any economic theory, the focus in this thesis is on macroeconomic theories of consumption, especially the Rational Expectations–Permanent Income Hypothesis proposed by Robert E. Hall in 1978. The much-debated theory suggests that, assuming that agents have rational expectations on their future income, consumption decisions should follow a random walk, and the best forecast of future consumption level is the current consumption level. Then, changes in consumption are unforecastable. This thesis constructs an empirical test for the Rational Expectations–Permanent Income Hypothesis using Finnish Consumer Survey data as well as various Finnish macroeconomic data. The data sample covers the years 1995–2010. Consumer survey data may be interpreted to directly represent household expectations, which makes it an interesting tool for this particular test. The variable to be predicted is the growth of total household consumption expenditure. The main empirical result is that the Consumer Confidence Index (CCI), a balance figure computed from the most important consumer survey responses, does have statistically significant predictive power over the change in total consumption expenditure. The history of consumption expenditure growth itself, however, fails to predict its own future values. This indicates that the CCI contains some information that the history of consumption decisions does not, and that the consumption decisions are not optimal in the theoretical context. However, when conditioned on various macroeconomic variables, the CCI loses its predictive ability. This finding suggests that the index is merely a (partial) summary of macroeconomic information, and does not contain any significant private information on consumption intentions of households not directly deductible from the objective economic variables. In conclusion, the Rational Expectations–Permanent Income Hypothesis is strongly rejected by the empirical results in this thesis. This result is in accordance with most earlier studies conducted on the topic.

Ordered Ports – a Language Concept for High-level Distributed Programming

A new language concept for high-level distributed programming is proposed. Programs are organised as a collection of concurrently executing processes. Some of these processes, referred to as liaison processes, have a monitor-like structure and contain ports which may be invoked by other processes for the purposes of synchronisation and communication. Synchronisation is achieved by conditional activation of ports and also through port control constructs which may directly specify the execution ordering of ports. These constructs implement a path-expression-like mechanism for synchronisation and are also equipped with options to provide conditional, non-deterministic and priority ordering of ports. The usefulness and expressive power of the proposed concepts are illustrated through solutions of several representative programming problems. Some implementation issues are also considered.

Non-industrial private forest landowners’ choices of timber management strategies.

The factors affecting the non-industrial, private forest landowners' (hereafter referred to using the acronym NIPF) strategic decisions in management planning are studied. A genetic algorithm is used to induce a set of rules predicting potential cut of the landowners' choices of preferred timber management strategies. The rules are based on variables describing the characteristics of the landowners and their forest holdings. The predictive ability of a genetic algorithm is compared to linear regression analysis using identical data sets. The data are cross-validated seven times applying both genetic algorithm and regression analyses in order to examine the data-sensitivity and robustness of the generated models. The optimal rule set derived from genetic algorithm analyses included the following variables: mean initial volume, landowner's positive price expectations for the next eight years, landowner being classified as farmer, and preference for the recreational use of forest property. When tested with previously unseen test data, the optimal rule set resulted in a relative root mean square error of 0.40. In the regression analyses, the optimal regression equation consisted of the following variables: mean initial volume, proportion of forestry income, intention to cut extensively in future, and positive price expectations for the next two years. The R2 of the optimal regression equation was 0.34 and the relative root mean square error obtained from the test data was 0.38. In both models, mean initial volume and positive stumpage price expectations were entered as significant predictors of potential cut of preferred timber management strategy. When tested with the complete data set of 201 observations, both the optimal rule set and the optimal regression model achieved the same level of accuracy.

Control of barrier height of MIS tunnel diodes using deep level impurities

The barrier height of MIS tunnel diodes is studied considering the effect of deep impurities. It is shown that the barrier height of a given MIS-system can be controlled by changing the density and the activation energy of the defect level. The study leads to the conclusion that deep impurities of character opposite to shallow impurities enhance the barrier height. On the other hand, the barrier height is lowered when the type of the deep impurities is the same as that of shallow impurities.

Litter quality and its response to water level drawdown in boreal peatlands at plant species and community level

Changes in the structure of plant communities may have much more impact on ecosystem carbon (C) cycling than any phenotypic responses to environmental changes. We studied these impacts via the response of plant litter quality, at the level of species and community, to persistent water-level (WL) drawdown in peatlands. We studied three sites with different nutrient regimes, and water-level manipulations at two time scales. The parameters used to characterize litter quality included extractable substances, cellulose, holocellulose, composition of hemicellulose (neutral sugars, uronic acids), Klason lignin, CuO oxidation phenolic products, and concentrations of C and several nutrients. The litters formed four chemically distinct groups: non-graminoid foliar litters, graminoids, mosses and woody litters. Direct effects of WL drawdown on litter quality at the species level were overruled by indirect effects via changes in litter type composition. The pristine conditions were characterized by Sphagnum moss and graminoid litters. Short-term (years) responses of the litter inputs to WL drawdown were small. In longterm (decades), total litter inputs increased, due to increased tree litter inputs. Simultaneously, the litter type composition and its chemical quality at the community level greatly changed. The changes that we documented will strongly affect soil properties and C cycle of peatlands.

Response of fungal and actinobacterial communities to water-level drawdown in boreal peatland sites

"We used PCR-DGGE fingerprinting and direct sequencing to analyse the response of fungal and actinobacterial communities to changing hydrological conditions at 3 different sites in a boreal peatland complex in Finland. The experimental design involved a short-term (3 years; STD) and a long-term (43 years; LTD) water-level drawdown. Correspondence analyses of DGGE bands revealed differences in the communities between natural sites representing the nutrient-rich mesotrophic fen, the nutrient-poorer oligotrophic fen, and the nutrient-poor ombrotrophic bog. Still, most fungi and actinobacteria found in the pristine peatland seemed robust to the environmental variables. Both fungal and actinobacterial diversity was higher in the fens than in the bog. Fungal diversity increased significantly after STD whereas actinobacterial diversity did not respond to hydrology. Both fungal and actinobacterial communities became more similar between peatland types after LTD, which was not apparent after STD. Most sequences clustered equally between the two main fungal phyla Ascomycota and Basidiomycota. Sequencing revealed that basidiomycetes may respond more (either positively or negatively) to hydrological changes than ascomycetes. Overall, our results suggest that fungal responses to water-level drawdown depend on peatland type. Actinobacteria seem to be less sensitive to hydrological changes, although the response of some may similarly depend on peatland type. (C) 2009 Elsevier Ltd. All rights reserved."