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Which trees should be removed in thinning treatments?

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Forest Ecosystems 2016年第1期3卷 51-62页

作者： Timo Pukkala erkki Lahde Olavi Laiho University of Eastern Finland PO Box 11180101 JoensuuFinland Joen Forest Program Consulting Rauhankatu 4180100 JoensuuFinland

Background： In economically optimal management, trees that are removed in a thinning treatment should be selected on the basis of their value, relative value increment and the effect of removal on the growth of remaining trees. Large valuable trees with decreased value increment should be removed, especially when they overtop smaller trees. Methods： This study optimized the tree selection rule in the thinning treatments of continuous cover managemen when the aim is to maximize the profitability of forest management. The weights of three criteria （stem value, relative value increment and effect of removal on the competition of remaining trees） were optimized together with thinning intervals. Results and conclusions： The results confirmed the hypothesis that optimal thinning involves removing predominantly large trees. Increasing stumpage value, decreasing relative value increment, and increasing competitive influence increased the likelihood that removal is optimal decision. However, if the spatial distribution of trees is irregular, it is optimal to leave large trees in sparse places and remove somewhat smaller trees from dense places. However, the benefit of optimal thinning, as compared to diameter limit cutting is not usually large in pure one-species stands. On the contrary, removing the smallest trees from the stand may lead to significant （30-40 %） reductions in the net present value of harvest incomes.

关键词： Continuous cover forestry Tree selection High thinning Optimal management Spatial distribution,Spatial growth model

Optimizing any-aged management of mixed boreal forest under residual basal area constraints

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Journal of Forestry Research 2014年第3期25卷 627-636页

作者： Timo Pukkala erkki L?hde Olavi Laiho University of Eastern Finland Faculty of Science and ForestryP.O. 111 80101 Joensuu Finland Joen Forest Program Consulting Rauhankatu 41 80100 Joensuu Finland

The current trend of forest management in many countries is reduced use of clear-felling and planting, and increased use of continuous cover management. In Finland, the new forest act of 2014 made all types of cuttings equally allowable on the condition that if the post-cutting residual stand basal area is too low, the stand must be regenerated within certain time frame. Forest landowner can freely choose between even-and uneven-aged management. This study developed a method for opti-mizing the timing and type of cuttings without the need to categorize the management system as either even-aged or uneven-aged. A management system that does not set any requirements on the sequence of post-cutting diameter distributions is called any-aged management. Planting or sow-ing was used when stand basal area fell below the required minimum basal area and the amount of advance regeneration was less than required in the regulations. When the cuttings of 200 stands managed earlier with even-aged silviculture were optimized with the developed system, final felling followed by artificial regeneration was selected for almost 50%of stands. Reduction of the minimum basal area limit greatly decreased the use of artificial regeneration but improved profitability, suggesting that the truly optimal management would be to use natural regeneration in financially mature stands. The optimal type of thinning was high thinning in 97-99%of cases. It was calculated that the minimum basal area re-quirement reduced the mean net present value of the stands by 12-16%when discount rate was 3-5%.

关键词： any-aged silviculture artificial regeneration continuous cover forestry optimal management uneven-aged management

Milk protein IgG and IgA:The association with milk-induced gastrointestinal symptoms in adults

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World Journal of Gastroenterology 2009年第39期15卷 4915-4918页

作者： Sari Anthoni erkki Savilahti Hilpi Rautelin Kaija-Leena Kolho Hospital for Children and Adolescents University of Helsinki Department of Bacteriology and Immunology Haartman InstituteUniversity of Helsinki and Helsinki University Central Hospital Laboratory

AIM:To study the association between serum levels of milk protein IgG and IgA antibodies and milk-related gastrointestinal symptoms in ***:Milk protein IgG and IgA antibodies were determined in serum samples of 400 subjects from five outpatient clinics in Southern *** were randomly selected from a total of 1900 adults undergoing laboratory investigations in primary *** 400 participants had completed a questionnaire on abdominal symptoms and dairy consumption while waiting for the laboratory *** questionnaire covered the nature and frequency of gastrointestinal problems,the provoking food items,family history and *** serum samples were disqualifi ed due to insuff icient amount of *** levels of specif ic milk protein IgG and IgA were measured by using the ELISA *** association of the milk protein-specific antibody level was studied in relation to the milk-related gastrointestinal symptoms and dairy ***:Subjects drinking milk(n=265) had higher levels of milk protein IgG in their sera than non-milk drinkers(n=123,P<0.001).Subjects with gastrointestinal problems related to milk drinking(n=119) consumed less milk but had higher milk protein IgG levels than those with no milk-related gastrointestinal symptoms(n=198,P=0.02).Among the symptomatic subjects,those reporting dyspeptic symptoms had lower milk protein IgG levels than non-dyspeptics(P<0.05).However,dyspepsia was not associated with milk drinking(P=0.5).The association of high milk protein IgG levels with constipation was close to the level of statistical signif *** had no association with milk protein IgG level(P=0.5).With regard to minor symptoms,flatulence and bloating(P=0.8),were not associated with milk protein IgG *** protein IgA levels did not show any association with milk drinking or abdominal *** levels of milk protein IgA and IgG declined as the age of the subjects increased(P<0.004).CONCLUSION:Milk

关键词： Abdominal symptoms Cow's milk Food hypersensitivity

Orthogonal nonnegative learning for sparse feature extraction and approximate combinatorial optimization

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Frontiers of Electrical and Electronic Engineering in China 2010年第3期5卷 261-273页

作者： erkki OJA Zhirong YANG Department of Information and Computer Science Aalto UniversityFI-00076 AaltoEspooFinland

Nonnegativity has been shown to be a powerful principle in linear matrix decompositions,leading to sparse component matrices in feature analysis and data *** classical method is Lee and Seung’s Nonnegative Matrix Factorization.A standard way to form learning rules is by multiplicative updates,maintaining ***,a generic principle is presented for forming multiplicative update rules,which integrate an orthonormality constraint into nonnegative *** principle,called Orthogonal Nonnegative Learning(ONL),is rigorously derived from the Lagrangian *** examples,the proposed method is applied for transforming Nonnegative Matrix Factorization(NMF)and its variant,Projective Nonnegative Matrix Factorization(PNMF),into their orthogonal *** general,it is well-known that orthogonal nonnegative learning can give very useful approximative solutions for problems involving non-vectorial data,for example,binary *** optimization is replaced by continuous-space gradient optimization which is often computationally *** is shown how the multiplicative updates rules obtained by using the proposed ONL principle can find a nonnegative and highly orthogonal matrix for an approximated graph partitioning *** empirical results on various graphs indicate that our nonnegative learning algorithms not only outperform those without the orthogonality condition,but also surpass other existing partitioning approaches.

关键词： nonnegative factorization sparse feature extraction orthogonal learning clustering

The quasi-biennial and semi-annual oscillation features of tropical O_3, NO_2, and NO_3 revealed by GOMOS satellite observations for 2002-2008

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Chinese Science Bulletin 2011年第18期56卷 1921-1929页

作者： LIU Yi LU ChunHui WANG Yong KYROLA erkki Key Laboratory. of Middle Atmosphere and Global Environment Observation Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China Finnish Meteorological Institute Earth Observation Helsinki Finland

The quasi-biennial oscillation (QBO) and semi-annual oscillation (SAO) characteristics of O3, NO2, and NO3 from 2002 to 2008 were analyzed using Global Ozone Monitoring by Occultation of Stars (GOMOS) satellite observations. From investigations of the vertical and latitudinal structures of interannual anomalies for O3 and the vertical velocity of the residual circulation (w-star), we conclude that dynamic transport is the principal factor controlling the QBO pattern of O3. Under the influence of vertical transport, the QBO signals of O3 originate in the middle stratosphere and propagate downward along with the wstar anomalies over the equator. The residual circulation has a significant role in tropical regions, regardless of altitude, while in extratropical regions, dynamic effects are important in some years in the lower stratosphere. In the middle stratosphere, dynamic transport is most efficient in the Southern Hemisphere. We also analyzed NO2 anomalies and found that their QBO pattern was deep and sta- tionary in the middle and upper stratosphere over the equator. This was due to the large depth over which w-star was anomalous. The latitudinal structure of NO2 was asymmetric in extratropical areas in the middle stratosphere, but in the upper layers, the QBO pattern and dynamic influences were only observed in tropical zones. The interannual anomalies of NO3 had an apparent SAO pattern in the tropical upper stratosphere because of different dynamic and chemical effects in different SAO phases. Chemical reactions may also have contributed to the QBO-type distribution of NO2 and the SAO-type distribution of NO3.

关键词：热带地区振荡特性卫星观测 NO2 O3 显示臭氧监测年际异常

High-sensitivity C-reactive protein in paediatric inflammatory bowel disease

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World Journal of Gastroenterology 2010年第23期16卷 2901-2906页

作者： Marianne Sidoroff Riitta Karikoski Taneli Raivio erkki Savilahti Kaija-Leena Kolho Division of Gastroenterology and Endocrinology Hospital for Children and AdolescentsUniversity of Helsinki Department of Pathology HUSLABHelsinki University Central Hospital

AIM:To study whether high-sensitivity C-reactive protein(hs-CRP) measurement can aid the assessment of disease activity and glucocorticoid treatment in paediatric inflammatory bowel disease(IBD).METHODS:CRP levels were measured in 39 children with IBD undergoing colonoscopy [median age 12.8 years,Crohn's disease(CD) n=20],in 22 other children with IBD followed for acute response to glucocorticoids,and in 33 paediatric non-IBD *** standard CRP level was below detection limit(<5mg/L),hs-CRP was ***:Sixty-four percent(25/39) of the children with IBD undergoing colonoscopy displayed undetectable(<5mg/L) standard CRP *** these,the hs-CRP measurement could not differentiate between active(median,0.2 mg/L,range,0.007-1.37,n=17) or quiescent(0.1 mg/L,0.01-1.89,n=8,P=NS) *** with ileocolonic CD had higher CRP levels(14mg/L,0.06-45,n=13) than patients with no ileal involvement(0.18 mg/L,0.01-9,n=7,P<0.01) or ulcerative colitis(UC)(0.13 mg/L,0.007-23,P<0.05).In children with active IBD treated with systemic glucocorticoids,the standard CRP was undetectable in 59% of the *** hs-CRP levels did not differ between patients that responded to steroid therapy and in ***:The measurement of hs-CRP did not prove useful in the assessment of disease activity or glucocorticoid treatment in paediatric IBD patients that had undetectable standard CRP.

关键词： C-reactive protein Crohn’s disease Ulcerative colitis Children Inflammatory markers

Compression curve analysis and compressive strength measurement of brittle granule beds in lieu of individual granule measurements

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Particuology 2016年第6期14卷 60-68页

作者： Matti Jairvelainen Aaretti Kaleva Annikka Kaitajairvi ,Jarmo Laakso Ulla Kanerva erkki Levanen Department of Materials Science Tampere University of Technology PO Box 589 FIN-33101 Tampere Finland VTT Technical Research Centre of Finland Sinitaival 6 PO Box 1300 FI33101 Tampere Finland

Powders in granulated form are used in various processes to facilitate convenient usage. The durability of the formed granules is a crucial parameter, typically evaluated by the compressive strength of the gran- ules. However, especially for granules with a diameter in the order of tens of microns, statistically relevant testing of individual granules is not a feasible alternative, and in such cases uniaxial bed compression is required. There has not been consensus on whether uniaxial compression of a granule bed can be used to study the fracture of micron size or brittle granules. In our case study of a bed of sintered kaolinite granules with diameters under 100 μm, we show how the compressive strength of individual granules can be obtained from the compressive measurement of the entire bed by plotting the relative density versus the logarithmic pressure scale. We compressed the kaolinite powder with different loads; microscopy confirmed that below the ana- lyzed strength the granules are intact, though the granules start to fracture in the curved region on the compression curve. We found that angle-fitting can be used to locate the average compressive strength on the compression curve and to follow the evolution of strength with sintering temperature. The experi- ments in unison demonstrate that compression curve analysis is applicable for strength analysis of brittle granules.

关键词： GranuleMechanical characterization Pressing Compressive strength Sintering Compression curves

Stand management optimization——the role of simplifications

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Forestry Studies in China 2014年第1期16卷 12-22页

作者： Timo Pukkala erkki Lhde Olavi Laiho Faculty of Science and Forestry University of Eastern Finland Joen Forest Program Consulting

Background:Studies on optimal stand management often make simplifications or restrict the choice of treatments,Examples of simplifications are neglecting natural regeneration that appears on a plantation site,omitting advance regeneration in simulations,or restricting thinning treatments to low thinning(thinning from below).Methods:This study analyzed the imparts of simplifications on the optimization results for Fennoscandian boreal *** of pine and spruce plantations was optimized by gradually reducing the number of simplifying ***:Forced low thinning,cleaning the plantation from the natural regeneration of mixed species and ignoring advance regeneration all had a major impact on optimization *** thinning(thinning from above) resulted in higher NPV and longer rotation length than thinning from *** was profitable to leave a mixed stand in the tending treatment of young *** advance regeneration was taken into account,it was profitable to increase the number of thinnings and postpone final *** the optimal management,both pine and spruce plantation was gradually converted into uneven-aged mixture of spruce and ***:The results suggest that,with the current management costs and timber price level,it may be profitable to switch to continuous cover management on medium growing sites of Fennoscandian boreal forests.

关键词： Plantation management Continuous cover forestry Even-aged management Mixed stands

Advantages of white LED lamps and new detector technology in photometry

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Light(Science & Applications) 2015年第1期4卷 216-222页

作者： Tomi Pulli Timo Donsberg Tuomas Poikonen Farshid Manoocheri Petri Karha erkki Ikonen Metrology Research Institute Aalto UniversityEspooFinland MIKES Metrology VTT Technical Research Centre of Finland LtdEspooFinland

Light emitting diode(LED)lighting is becoming more and more popular,as incandescent lamps are being phased out *** have several advantages over incandescent lamps,including energy efficiency,robustness,long lifetime,and good temporal *** three latter features make LEDs attractive candidates as new photometric *** the spectra of white LEDs are limited to the visible wavelength range,a novel method for the realization of photometric units based on the predictable quantum efficient detector(PQED)can be *** method eliminates the need of photometric filters that are traditionally used in photometry,and instead relies on carrying out the photometric weighting numerically based on the measured relative spectrum of the *** PQED-based realization simplifies the traceability chain of photometric measurements significantly as compared with the traditional filter-based *** measured illuminance values of a white LED deviate by only 0.03%when determined by the new and the traditional *** new PQED method has significantly lower expanded uncertainty of 0.26%(k=52)as compared with that of the traditional filter-based method of 0.42%(k=52).Furthermore,when filtered photometers that measure LED lighting are calibrated using LED lamps as calibration sources instead of incandescent lamps,a significant decrease in the uncertainty related to the spectral mismatch correction can be *** maximum spectral mismatch errors of LED measurements decreased on average by a factor of 3 when switching from an incandescent lamp to an LED calibration source.

关键词： LED optical metrology photometry standard lamp