bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of lodgepole pine yield tables
Authors: Thomson Alan J.
Published: April 2008

Iterative solution of equations from Johnstone's variable-density yield tables for lodgepole pine permitted estimates of stand development index (DI) and productivity index (PI) from the volume, quadratic mean of diameter at breast height, basal area, or dominant–condominant height associated with a particular stand density at a particular age. Using such estimates, the yield tables of Smithers were compared with those of Johnstone. PI values associated with each of Smithers' site indices were calculated for British Columbia and Alberta. Results suggested that Johnstone's equations could be used in lodgepole pine stands in both British Columbia and Alberta, for PI values from 0.7 to 1.2, for densities up to 2500 stems acre−1 at age 70, and for ages up to 120. This considerably extends the range of application of these equations.
Water stress and survival of three species of conifer seedlings planted on a high elevation south-facing clear-cut
Authors: Livingston N. J. , Black T. A.
Published: April 2008

Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), western hemlock (Tsugaheterophylla (Raf.) Sarg.), and Pacific silver fir (Abiesamabilis (Dougl.) Forbes) container-grown 1-0 seedlings were spring planted on a south-facing high elevation clear-cut located on Mount Arrowsmith, Vancouver Island, British Columbia. Treatments, which included inclining seedlings to the southwest, provision of shade cards, irrigation, and irrigation and shade cards combined, were applied to determine whether modification of seedling microclimate would increase survival. Highest survival rates, regardless of treatment, were shown by Douglas-fir. By April 1984, 72 and 82% of untreated Douglas-fir seedlings planted in 1981 and 1982, respectively, survived, whereas survival of treated seedlings ranged from 81 to 95%. The high survival rate in Douglas-fir appeared to be due to their high drought tolerance. The osmotic potential of unirrigated Douglas-fir seedlings declined by over 1.1 MPa during the course of the 1982 growing season in response to decreasing soil water potentials and consequently turgor was maintained in the foliage. Transpiration rates of these seedlings were never less than 50% of those that were irrigated. Western hemlock and Pacific silver fir seedlings exhibited very poor survival, possibly owing to the lack of stress avoidance and tolerance mechanisms. Survival rates of the two species were increased by shade cards and irrigation but never exceeded 64%.
Somatic polyembryogenesis in embryogenic cell masses of Piceaabies (Norway spruce) and Pinustaeda (loblolly pine) after thawing from liquid nitrogen
Authors: Gupta P. K. , Durzan D. J. , Finkle B.J.
Published: April 2008

We describe a method for the possible cryopreservation of embryogenic callus of Piceaabies and Pinustaeda at −196 °C and the regeneration of somatic embryos from thawed cells of subcultured embryonal–suspensor masses. Piceaabies and Pinustaeda were frozen without cryoprotective agent, in the presence of dimethyl sulfoxide (10%), or in a mixture of polyethylene glycol, glucose, and dimethylsulfoxide (10, 8, and 10% w/v, respectively). Cell masses placed in plastic vials or aluminum envelopes were frozen at 1 °C/min to −30 °C and then immersed for 10 min in liquid nitrogen. Cells were thawed rapidly and placed on modified MS subculture medium. Six to seven somatic embryos per gram of fresh weight were regenerated from each piece of frozen cell mass as compared with 12–13 embryos per gram from unfrozen cells. Post-thaw cell growth was inhibited initially by up to 5 weeks. Inhibition was reversed after the third 10-day subculture. Results suggest that the long-term storage of embryogenic cell lines in liquid nitrogen may be feasible for tree improvement programs in circumstances where testing of progeny may take several years.
Genetic variation in trembling aspen in Ontario based on isozyme studies
Authors: Hyun Jung O. , Rajora Om P. , Zsuffa Louis
Published: April 2008

Isoenzyme studies were conducted on root tips of 200 Populustremuloides clones selected from eight geographic regions (populations) along north–south and east–west transects in Ontario. Starch gel electrophoresis was used to assay crude enzyme extracts from young root rips of rooted suckers obtained from the clones sampled. A total of 15 isozyme loci coding for eight different enzyme systems were resolved. The mean of total gene diversity was 0.252. An average of 79% of the loci were polymorphic in any one population, with an average of 2.7 alleles per locus. More than 90% of the genetic variability could be attributed to within-population differentiation. A deficiency of observed heterozygotes was calculated for all populations studied. The fixation index averaged 0.462. The genetic distance estimates among populations had an overall mean of 0.103. There was no correlation between genetic and geographic distances. Results of this study suggest this species in its Ontario range is genetically variable and moderately differentiated.
The effects of simulated acid precipitation in the surface horizons of two eastern Canadian forest Podzol soils
Authors: Thacker D. J. , Rutherford G. K. , Vanloon G.W.
Published: April 2008

Undisturbed 18-cm soil cores of the L, F, H, Ae, and upper Bhf horizons of Ferro-Humic Podzols from the Turkey Lake Watershed (Ontario) and Montmorency Forest (Quebec) were treated in the laboratory with 10 m of simulated acid precipitation at pH 5.7, 3.5, and 2.0 over approximately 1 year. Leachate samples were collected from the bottom of the humus layer and the bottom of the soil core and the soils were analyzed at the completion of leaching. The soils from the two sites behaved similarly. Anion concentrations in the leachates adjusted to input levels after approximately 2 m of simulated rainfall. Leaching generally produced an initial flush of cations followed by lower concentrations. The pH 2.0 treatment caused major changes in some soil properties; the pH 3.5 and 5.7 treatment had a more modest effect. Base saturation was markedly reduced following the pH 2.0 treatment, slightly reduced following the pH 3.5 treatment, and slightly increased following the distilled water treatment. Cation exchange capacity was reduced only in the organic horizons receiving pH 2.0 treatment. Organic C, total N, and C/N ratios showed no changes on acidification. Leaching of Fe and Al was only substantial with the pH 2.0 treatment and much more Al than Fe was mobilized. Bicarbonate – extractable P in the mineral soil was doubled by the pH 2.0 treatment compared with the other treatments. X-ray diffraction of clays indicated a loss of hydroxyaluminum interlayers with increasing acidity, which is a stage in the acidic transformation of micaceous to smectite-like materials in Podzolic soils.
Root respiration has limited value for assessing Douglas-fir seedling quality
Authors: McCreary Douglas D. , Zaerr Joe B.
Published: April 2008

Root damage is a principal cause of poor seedling quality. Currently, the most widely used seedling-quality test measures a seedling's ability to initiate and elongate roots in a favorable environment; however, this test requires a lengthy response period and tedious, time-consuming measurements. Alternatively, the respiration rate of roots could be measured much more quickly and easily. Results of this study, which examined whether root respiration could successfully predict the survival and growth of potted Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings in a growth room, indicated that respiration may help assess root damage caused by desiccation but not that caused by freezing, hot storage, or rapid heating.
Estimation of wood density in family tests of jack pine and black spruce using the Pilodyn tester
Authors: Villeneuve M. , Morgenstern E. K. , Sebastian L. P.
Published: April 2008

Wood density is one of the traits considered for the genetic improvement of Pinusbanksiana Lamb. and Piceamariana (Mill.) B.S.P. in New Brunswick. For both species, family tests based on open-pollinated parents are measured to retain only about 10% of the best families in seedling orchards. The development of a suitable sampling method using the Pilodyn wood tester to rank families is discussed. It was found that Pilodyn estimates at early ages are reliable for P. banksiana only. A sample of one tree in each of five replications in a single test location yields an estimate of wood density with an acceptable coefficient of variation.
Genetic variances among clonally propagated populations of tamarack and the implications for clonal forestry
Authors: Park Y. S. , Fowler D. P.
Published: April 2008

Genetic variances of three tamarack (Larixlaricina (Du Roi) K. Koch.) populations in central New Brunswick were examined using vegetatively propagated materials. The component of variance due to clones within families was large for both 5-year height and survival and was partitioned into additive and nonadditive genetic variances. About 85% of the clonal variance for height was additive for the AFES and CANAAN populations but was only 18% for the NORTON population. For survival, the proportion of nonadditive variance was larger than additive variance for the AFES and CANAAN populations, whereas for the Norton population it was negligible. The possibility of clonal propagation and selection is explored as a tree improvement –reforestation option and a strategy is discussed.
An assessment of the structural method of deriving a black spruce site equation
Authors: Smith Victor G. , Watts Martin
Published: April 2008

To date, methods of deriving site index (S) equations assume that stochastic error is only present in the regressor. This paper develops a method, termed the "structural method," which recognizes that both dominant stand height (H) and S measurements contain stochastic error. To achieve this, the structural method utilizes the structural relationship that exists between H and S to derive an S equation. S equations are derived for black spruce, Piceamariana (Mill.) B.S.P., using the structural method and various other methods, with linear and nonlinear models that are currently in use. Data used in the study consist of 56 black spruce permanent sample plots, containing a total of 382 observations, from north central Ontario and the Clay Belt Region of northern Ontario. This data set is split into 36 plots (260 observations) for deriving S equations and 20 plots (122 observations) for testing the equations for accuracy in predicting H, S, and future H. The equations are also examined for bias over stand age. Results show that height development of black spruce is not asymptotic and is best described by a linear model. Overall, the structural method provides the most accurate S equation within the range of the data. It predicted 90% of the H test observations with an error of 0.4 m or less, 89% of the S test observations with an error of 0.4 m or less, and 90% of the future H test observations with an error of 0.7 m or less. The structural method also has the advantage of producing only one equation for predicting both H and S. This enables estimates of both H and S to be made from one graph of H over age by S classes.
Effects of frost on shaded and exposed spruce and pine seedlings planted in the field
Authors: Lundmark Tomas , Hällgren Jan-Erik
Published: April 2008

Spruce (Piceaabies L.) and pine (Pinussylvestris L.) seedlings were planted at different positions relative to artificial tree shades. Two sites in northern Sweden known as difficult to regenerate owing to frosts during the growing season were used. No deficiency of soil water was recorded during the growing season and all seedlings experienced similar temperature conditions during night frosts. Exposed seedlings received on clear days 7 h more of direct solar radiation than did shaded seedlings. After the first severe night frost in August, discoloration of needles and a decrease in chlorophyll concentration as well as lowered photosynthetic rates were more pronounced for the exposed seedlings. This was more obvious for spruce than pine seedlings. The differences in radiant load seem to be of ultimate importance for the results observed. It is proposed that photoinhibition and subsequent photooxidation of planted seedlings occur in the field when severe night frosts are followed by clear days with high irradiance.
Composition of loblolly pine resin defenses: comparison of monoterpenes from induced lesion and sapwood resin
Authors: Paine T. D. , Blanche C. A. , Nebeker T. E. , Stephen F.M.
Published: April 2008

Even-aged loblolly pines in three crown classes chosen to represent varying levels of vigor were inoculated with the blue-stain fungus Ceratocystisminor to induce hypersensitive tissue formation. There were no differences in monoterpene composition of the induced tissue among crown classes growing on the same site. However, there were significant differences in percent composition of individual monoterpenes between trees growing on a poorer wet site and those growing on a better dry site. There were also quantitative and qualitative differences in monoterpene composition of preformed xylem resin compared with the monoterpenes extracted from the hypersensitive tissue. The differences in composition between the preformed resin and resin found in the hypersensitive tissue may reflect, in part, the energy requirements for initiation of the inducible system.
Distribution of residual vegetation associated with large fires in Alberta
Authors: Eberhart Kevin E. , Woodard Paul M.
Published: April 2008

Fire size and shape, number and size of islands of residual vegetation, amount of edge, and distances to residual vegetation were analyzed for 69 fires that burned in Alberta between 1970 and 1983. These fires ranged in size from 21 to 17 770 ha. Distribution of residual vegetation was compared among five fire size classes. Fires in the smallest size class (20–40 ha) did not contain any islands of unburned vegetation. Percent of area within the fire perimeter that was actually disturbed decreased with increasing fire size. The number of unburned islands per 100 ha was highest for the third and fourth largest fire size classes (201–400 and 401–2000 ha). Median island area per fire, fire shape index, and edge index increased with fire size. Percentages of burned area within 100, 200, 300, 400, and 500 m of residual vegetation decreased with increasing fire size. These results indicate decreased potential for natural reforestation and increased benefits to some wildlife habitats as fire size increases.
Radial and longitudinal variation in stem diameter increment of lodgepole pine, white spruce, and black spruce: species and crown class differences
Authors: Clyde Merlise A. , Titus Stephen J.
Published: April 2008

Radial and longitudinal variation in stem diameter increment were examined in lodgepole pine (Pinuscontorta var. latifolia Engelm.), white spruce (Piceaglauca (Moench) Voss), and black spruce (Piceamariana (Mill.) B.S.P.) in Alberta using graphical techniques. Three-dimensional surfaces of diameter increment at various heights and ages differed among the three species and dominant, codominant, and intermediate crown classes within each species. Relative to the maximum growth rate, black spruce and white spruce maintain higher and more constant levels of diameter increment over time than lodgepole pine. Variation among species probably reflects differences in shade tolerance, while differences among crown classes within a species are probably related to shading and wind stress effects. There were more similarities among the diameter increment surfaces for the three crown classes in lodgepole pine than in the two spruces. The stem diameter increment surfaces help explain the development of differences in stem form among the three species.
Nitrogen fixation in woody residue of northern Rocky Mountain conifer forests
Authors: Jurgensen M. F. , Larsen M. J. , Graham R. T. , Harvey A. E.
Published: April 2008

N fixation rates, as estimated by the acetylene reduction technique, were determined for large woody residues on four old growth conifer sites in western Montana and northern Idaho. Residue loadings ranged from <50 Mg ha−1 on a warm, dry Douglas-fir site in Montana to >150 Mg ha−1 on a highly productive, wet, cedar–hemlock site in northern Idaho. Lignin and carbohydrate analyses indicated that wood on these sites was being decayed primarily by brown rot fungi. Ethylene production rates increased on all sites as wood decay progressed. Assuming that N-fixing bacteria were active for 180 days year−1, N fixed in woody residues ranged from a high of nearly 1.5 kg ha−1 year−1 on a cedar–hemlock site to a low of 0.16 kg ha−1 year−1 on a Douglas-fir site. The application of the N fixation results from this study to the northern Rocky Mountain region indicated that the majority of stands in the Douglas-fir, subalpine fir, and cedar–hemlock cover types would have N gains <0.5 kg ha−1 year−1. However, in some areas where residue loadings are heavy, such as overmature stands on cool, moist sites, or following harvesting, N gains could be much greater.
Promotion of embryogenesis in cultured megagametophytes of Larixdecidua
Authors: Aderkas P. von , Bonga J. M. , Nagmani R.
Published: April 2008

In the summer of 1985, female gametophytic explants of Larixdecidua were cultured on LM medium containing 2,4-D (2.0 mg/L). In the subsequent growing season (1986), various concentrations of 2,4-D (0, 0.2, 2.0, and 20 mg/L) were used as media supplements and evaluated in material collected weekly from early June to late July. Optimal induction of callus and embryogenesis occurred at 2.0 mg/L 2,4-D and depended on collection date. Two kinds of callus were produced, a white embryogenic callus developed from explants from late June onwards, and a green nonembryogenic callus developed from middle to late July. Various concentrations of sucrose and sorbitol were tested in osmotically equivalent combinations together with the optimal level of 2,4-D (2.0 mg/L). The production of embryogenic callus was best on 3% sucrose and no sorbitol. Embryogenic callus developed from both chalazal and micropylar portions of the excised megagametophyte.
Comparison of standard and actual tree-growth trends for deciduous and coniferous species in New Hampshire
Authors: Leak W. B.
Published: April 2008

Recent concerns over the decline of tree growth in the Northeast have revealed the need for data on standard or expected tree growth over time or tree diameter, unaffected by stand or climatic factors. Examples of standard growth curves are developed and compared with past sample-tree increments on 30 plots with a known 52- to 53-year record of change in stand density.
Bud production of Douglas-fir (Pseudotsugamenziesii) seedlings: response to shrub and hardwood competition
Authors: Tappeiner II John C. , Hughes Thomas F. , Tesch Steven D.
Published: April 2008

Shrubs and hardwoods in five plantations of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) in southwestern Oregon were treated to obtain four or five levels of competition; cover ranged from 0 (complete control) to 100% (no treatment). On four of the five plantations, Douglas-fir seedlings significantly increased bud production on the leader in the first growing season after treatment. Buds were more responsive to level of competition than were leader length or growth in stem diameter, for which significant differences were not usually observed until the second growing season after treatment. Bud number on the leader apparently is a good indicator of seedling vigor. Leader, stem diameter, and stem cross-sectional area growth in the 2nd and 3rd years after treatment were positively correlated with the number of buds produced on the leader in the first growing season following treatment.
Estimating the surface area of spruce and pine foliage from displaced volume and length
Authors: Brand David G.
Published: April 2008

Accurate determination of the surface area of needle-leaved trees is a basic requirement for many types of physiological or growth analysis studies in forest research. While many methods are available to estimate surface area, there is still a need for an accurate, rapid measurement technique for species with three- or four-sided needle morphology. I propose a regression technique with length and displaced volume as the independent variables. The regression technique is an improvement over the use of displaced volume and length in direct geometric calculation as it does not assume a constant needle morphology. The regression technique gives more accurate results than direct calculation, is comparable in precision, and is necessary to counter bias where variation in the cross-sectional shape of foliage is related to the treatment or variable under study. Use of regression, however, requires that a subsample of foliage, representing the range of conditions to be studied, be sectioned and measured directly for surface area to develop the estimation equation.
A fundamental inequality for the assessment of forest land values
Authors: Löfgren Karl Gustaf
Published: April 2008

In this paper one well-known property and one less known property of the present value function are used to provide upper and lower bounds on the change in the value of forest land when land value is evaluated at any two different discounted price vectors. The lower bound is expressed in possibly known entities of the original harvesting program.
Changes in osmotic potential, cell elasticity, and turgor relationships of 2nd-year black spruce container seedlings
Authors: Colombo S. J.
Published: April 2008

not available
Climatic change: a review of causes
Authors: Harrington J. B.
Published: April 2008

The earth's climate is constantly changing. Climatic change is effected by many factors: the influence of continental drift, variations in solar intensity, volcanism, the impact of meteors and comets, changes in the earth's orbital parameters, ice accumulation and depletion, variations in oceanic circulations and chemistry, changes in terrestrial and aquatic life, and changes in atmospheric composition and circulation. Despite these influences, many of them large, and despite changes in the sun's radiant intensity over the past 4.5 billion years, the average temperature of the earth's surface has remained remarkably constant, hovering near 15 °C. This implies the presence of strong negative feedbacks reacting to any major environmental change. During the past century, man's influence on his environment has been increasing at an unprecedented rate. Under this influence, and particularly because of the effect of the so-called "greenhouse gases," the global mean temperature is expected to rise approximately 2.5 °C by the middle of the 21st century. There remains a degree of uncertainty in this prediction because of unresolved problems in estimating various positive and negative feedback mechanisms in air, earth, ocean, ice, and vegetation interaction and in the unknown magnitude of volcanic activity. The finest numerical models and the fastest computers are, at present, inadequate to resolve all of the problems. However, the best scientific evidence points to a return by the middle of the 21st century to a climate similar to that of the climatic optimum 5000–6000 years ago. The degree of confidence in the direction, speed, and magnitude of the impending climatic change is sufficient that affected agencies should be actively mapping strategies to respond most advantageously to the expected changes. This is particularly true of forestry in Canada where climatic changes are expected to be large and the lifetime of current plantings will extend well into the period of anticipated change.
Étiologie du chancre godronien du bouleau jaune
Authors: Desprez-Loustau M. L. , Dessureault M.
Published: April 2008

Etiology of Godroniacassandrae Peck. f. sp. betulicola Groves was investigated on naturally growing yellow birch (Betulaalleghaniensis Britt.) seedlings. Spores, mainly conidia, were trapped over the entire growing season with a maximum in June–July, a period during which infections are most frequent. Spore dispersal was closely related to the amount and duration of rainfall. Optimal temperature for conidium and ascospore germination was 18–22 °C. Although the fungus grows best at 18 °C, growth still occurs at 1 °C. The pathogen can remain alive but inactive for long periods of time in the host tissues and spreads mostly when hosts are dormant or weakened. Symptom progression depends largely on the physiological condition of the seedlings and the size of infected branches.
Increased biomass production by tissue culture of eucalyptus
Authors: Khuspe S. S. , Gupta P. K. , Kulkarni D. K. , Mehta Urmil , Mascarenhas A. F.
Published: April 2008

Buds collected from elite fast-growing eucalyptus trees were multiplied by tissue culture. In this study, the seed (control) and the tissue culture raised plants of Eucalyptustereticornis and E. torelliana were planted in the field at two population densities. Observations of the height and diameter were taken for biomass calculation. Thirty-four months after planting, there was an overall increase in biomass of the tissue culture raised plants of both species compared with the controls. In E. tereticornis and E. torelliana, the increase in biomass was 36.9 and 49.5%, respectively, over the controls with a 2 × 2 m spacing.
Successional changes in nitrogen availability as a potential factor contributing to spruce declines in boreal North America
Authors: Pastor J. , Gardner R. H. , Dale V. H. , Post W. M.
Published: April 2008

This paper examines the hypothesis that the depression of soil nitrogen availability by litter from black and white spruce (Piceamariana and P. glauca), which is low in nitrogen and high in recalcitrant compounds, may lead directly to spruce decline or predispose the forest to dieback from other factors. A set of model simulations based on principles and information developed independently of current episodes of spruce decline demonstrates the importance of this mechanism to cycles of boreal forest declines. The model also shows that if litter of red spruce (P. rubens) has a similar effect on the nitrogen cycle, then the effect of acid deposition on red spruce decline must be considered in light of this intrinsic property of spruce ecosystems. Because of the confounded nature of ecosystem variables, a neutral modeling approach is a necessary framework for exploring the combined effects of nutrients, drought, changing climate, and pollution on forest diebacks, for directing site selection and field measurements, and for synthesizing results of field and laboratory experiments in an ecosystem context.
Combining taper functions and critical height sampling for unbiased stand volume estimation
Authors: Van Deusen Paul C.
Published: April 2008

New estimators have been developed for critical height sampling that allow any taper function to be used as a variance reduction mechanism. The new estimators are compatible with current horizontal point sampling procedures and will lead to unbiased estimates of cubic volume and cubic volume growth. It is proposed that critical height sampling should replace horizontal point sampling when one upper stem measurement can be made, because horizontal point sampling relies on predicted tree volumes and the assumption that resulting stand volume predictions are unbiased.
Techniques for assessing the effects of pest hazards on long-run timber supply
Authors: Reed William J. , Errico Darrell
Published: April 2008

Stand-level and forest-level models are developed for the purpose of assessing the effects of pest hazards on long-term timber supply. The stand-level model yields formulas for the long-run average yield and the land expectation value when both the risk of infestation by pests and the risk of total destruction by fire are present. Infestations are assumed to occur with a probability dependent upon stand age. A forest-level harvest scheduling procedure of the model II type, which allows for pest infestation and fire destruction, is developed. Numerical examples are given, using data for lodgepole pine in the Quesnel Timber Supply Area of British Columbia, assuming various patterns of infestation by mountain pine bark beetle.
Stand growth projection: simultaneous estimation of growth and mortality using a single probabilistic function
Authors: Lowell K. E. , Mitchell R. J.
Published: April 2008

Logistic regression analysis can be used to estimate the probability of a binary event. In forestry, its use largely has been limited to predicting the probability of mortality of individual trees. However, the potential for broader application in forest growth and yield modelling has largely been overlooked. A logistic model to predict the probability that a tree will attain a specified future diameter can be produced by establishing a series of growth "success" criteria. Given the initial diameter distribution of a forest stand, a future diameter distribution and stand characteristics can be estimated probabilistically by estimating the proportion of stems in each diameter class of the distribution which attains a specified future diameter (the "success" criterion) and the proportion which fails to achieve at least zero growth (i.e., mortality). Using permanent plot data, such a logistic model was calibrated and validated for an oak–hickory forest in southeastern Missouri. Validation indicated that the model performs satisfactorily (estimates are unbiased) for individual trees over a 5-year prediction period, and for stand characteristics over 5-, 10-, 15-, and 20-year prediction periods though precision suffers as prediction period lengthens.
On a social discount rate for forestry: Comment
Authors: Price Colin
Published: April 2008

not available
On a social discount rate for forestry: Reply
Authors: Harou Patrice
Published: April 2008

not available
POLARIZED SIGNAL CLASSIFICATION BY COMPLEX AND QUATERNIONIC MULTI-LAYER PERCEPTRONS
Authors: BUCHHOLZ SVEN , LE BIHAN NICOLAS
Published: April 2008

For polarized signals, which arise in many application fields, a statistical framework in terms of quaternionic random processes is proposed. Based on it, the ability of real-, complex- and quaternionic-valued multi-layer perceptrons (MLPs) of performing classification tasks for such signals is evaluated. For the multi-dimensional neural networks the relevance of class label representations is discussed. For signal to noise separation it is shown that the quaternionic MLP yields an optimal solution. Results on the classification of two different polarized signals are also reported.
FLEXIBLE NONLINEAR BLIND SIGNAL SEPARATION IN THE COMPLEX DOMAIN
Authors: VIGLIANO DANIELE , SCARPINITI MICHELE , PARISI RAFFAELE , UNCINI AURELIO
Published: April 2008

This paper introduces an Independent Component Analysis (ICA) approach to the separation of nonlinear mixtures in the complex domain. Source separation is performed by a complex INFOMAX approach. The neural network which realizes the separation employs the so called "Mirror Model" and is based on adaptive activation functions, whose shape is properly modified during learning. Nonlinear functions involved in the processing of complex signals are realized by pairs of spline neurons called "splitting functions", working on the real and the imaginary part of the signal respectively. Theoretical proof of existence and uniqueness of the solution under proper assumptions is also provided. In particular a simple adaptation algorithm is derived and some experimental results that demonstrate the effectiveness of the proposed solution are shown.
THE UNIQUENESS THEOREM FOR COMPLEX-VALUED NEURAL NETWORKS WITH THRESHOLD PARAMETERS AND THE REDUNDANCY OF THE PARAMETERS
Authors: NITTA TOHRU
Published: April 2008

This paper will prove the uniqueness theorem for 3-layered complex-valued neural networks where the threshold parameters of the hidden neurons can take non-zeros. That is, if a 3-layered complex-valued neural network is irreducible, the 3-layered complex-valued neural network that approximates a given complex-valued function is uniquely determined up to a finite group on the transformations of the learnable parameters of the complex-valued neural network.
PSEUDO-RELAXATION LEARNING ALGORITHM FOR COMPLEX-VALUED ASSOCIATIVE MEMORY
Authors: KOBAYASHI MASAKI
Published: April 2008

HAM (Hopfield Associative Memory) and BAM (Bidirectinal Associative Memory) are representative associative memories by neural networks. The storage capacity by the Hebb rule, which is often used, is extremely low. In order to improve it, some learning methods, for example, pseudo-inverse matrix learning and gradient descent learning, have been introduced. Oh introduced pseudo-relaxation learning algorithm to HAM and BAM. In order to accelerate it, Hattori proposed quick learning. Noest proposed CAM (Complex-valued Associative Memory), which is complex-valued HAM. The storage capacity of CAM by the Hebb rule is also extremely low. Pseudo-inverse matrix learning and gradient descent learning have already been generalized to CAM. In this paper, we apply pseudo-relaxation learning algorithm to CAM in order to improve the capacity.
CHAOTIC SYNCHRONIZATION USING A NETWORK OF NEURAL OSCILLATORS
Authors: CHAKRAVARTHY V. SRINIVASA , GUPTE NEELIMA , YOGESH S. , SALHOTRA ATUL
Published: April 2008

Synchronization of chaotic low-dimensional systems has been a topic of much recent research. Such systems have found applications for secure communications. In this work we show how synchronization can be achieved in a high-dimensional chaotic neural network. The network used in our studies is an extension of the Hopfield Network, known as the Complex Hopfield Network (CHN). The CHN, also an associative memory, has both fixed point and limit cycle or oscillatory behavior. In the oscillatory mode, the network wanders chaotically from one stored pattern to another. We show how a pair of identical high-dimensional CHNs can be synchronized by communicating only a subset of state vector components. The synchronizability of such a system is characterized through simulations.
RIGOROUS DERIVATION OF THE HYDRODYNAMICAL EQUATIONS FOR ROTATING SUPERFLUIDS
Authors: LIU HAILIANG , SPARBER CHRISTOF
Published: April 2008

Using a modified WKB approach, we present a rigorous semiclassical analysis for solutions of nonlinear Schrödinger equations with rotational forcing. This yields a rigorous justification for the hydrodynamical system of rotating superfluids. In particular, it is shown that global-in-time semiclassical convergence holds whenever the limiting hydrodynamical system has global smooth solutions and we also discuss the semiclassical dynamics of several physical quantities describing rotating superfluids.
A BASIC CONVERGENCE RESULT FOR CONFORMING ADAPTIVE FINITE ELEMENTS
Authors: MORIN PEDRO , SIEBERT KUNIBERT G. , VEESER ANDREAS
Published: April 2008

We consider the approximate solution with adaptive finite elements of a class of linear boundary value problems, which includes problems of "saddle point" type. For the adaptive algorithm we assume the following framework: refinement relies on unique quasi-regular element subdivisions and generates locally quasi-uniform grids, the finite element spaces are conforming, nested, and satisfy the inf–sup conditions, the error estimator is reliable as well as locally and discretely efficient, and marked elements are subdivided at least once. Under these assumptions, we give a sufficient and essentially necessary condition on marking for the convergence of the finite element solutions to the exact one. This condition is not only satisfied by Dörfler's strategy, but also by the maximum strategy and the equidistribution strategy.
A CONSTRUCTION OF SPACES OF COMPATIBLE DIFFERENTIAL FORMS ON CELLULAR COMPLEXES
Authors: CHRISTIANSEN SNORRE H.
Published: April 2008

Given a cellular complex, we construct spaces of differential forms which form a complex under the exterior derivative, which is isomorphic to the cochain complex of the cellular complex. The construction applies in particular to subsets of Euclidean space divided into polyhedra, for which it provides, for each k, a space of k-forms with a basis indexed by the set of k-dimensional cells. In the framework of mimetic finite differences, the construction provides a conforming reconstruction operator. The construction requires auxiliary spaces of differential forms on each cell, for which we provide two examples. When the cells are simplexes, the construction can be used to recover the standard mixed finite element spaces also called Whitney forms. We can also recover the dual finite elements previously constructed by A. Buffa and the author on the barycentric refinement of a two-dimensional mesh.
COMPUTING THE CONVEX ENVELOPE USING A NONLINEAR PARTIAL DIFFERENTIAL EQUATION
Authors: OBERMAN ADAM M.
Published: April 2008

A fully nonlinear partial differential equation for the convex envelope was recently introduced by the author. In this paper, the equation is discretized using a finite difference method. The resulting scheme yields an explicit local method to compute the convex envelope. The scheme is shown to converge. Computational results are presented for smooth and nonsmooth data. Extensions to higher dimensions and unstructured grids are discussed.
QUALITATIVE ANALYSIS OF THE KHOKHLOV–ZABOLOTSKAYA–KUZNETSOV (KZK) EQUATION
Authors: ROZANOVA-PIERRAT ANNA
Published: April 2008

The Khokhlov–Zabolotskaya–Kuznetzov (KZK) equation is considered as a model of nonlinear acoustic which describes the nonlinear propagation of a finite-amplitude focused sound beam which is essentially one-directional, in the thermo-viscous medium.1,7,8 The aim of this paper is the study of the existence, uniqueness, stability, regularity, continuous dependence on the initial value and blow-up of solution of the KZK equation in Sobolev spaces Hs of periodic on x functions and with mean value zero. Existence of shock waves for the model with zero viscosity is proved using S. Alinhac's method.2 Global existence in time of the beam's propagation in viscous media is established for small enough initial data. Existence result is proved by two methods: first by the fractional step method in the particular case ℝ3 and s = 3 to justify the numerical results of Thierry Le Pollès25 and second for the general case ℝn and s > [n/2] + 1 by the approach used in Refs. 12 and 13 for the Kadomtsev–Petviashvili (KP) equation.
CHARACTERIZING TREES IN CONCEPT LATTICES
Authors: BĚLOHLÁVEK RADIM , DE BAETS BERNARD , OUTRATA JAN , VYCHODIL VILEM
Published: April 2008

Concept lattices are systems of conceptual clusters, called formal concepts, which are partially ordered by the subconcept/superconcept relationship. Concept lattices are basic structures used in formal concept analysis. In general, a concept lattice may contain overlapping clusters and need not be a tree. On the other hand, tree-like classification schemes are appealing and are produced by several clustering methods. In this paper, we present necessary and sufficient conditions on input data for the output concept lattice to form a tree after one removes its least element. We present these conditions for input data with yes/no attributes as well as for input data with fuzzy attributes. In addition, we show how Lindig's algorithm for computing concept lattices gets simplified when applied to input data for which the associated concept lattice is a tree after removing the least element. The paper also contains illustrative examples.
INTEGRATION OF A CONSISTENCY CONTROL MODULE WITHIN A CONSENSUS MODEL
Authors: CHICLANA FRANCISCO , MATA FRANCISCO , MARTINEZ LUIS , HERRERA-VIEDMA ENRIQUE , ALONSO SERGIO
Published: April 2008

In group decision making (GDM) processes, prior to the selection of the best alternative(s), it would be desirable that experts achieve a high degree of consensus or agreement between them. Due to the complexity of most decision making problems, individuals' preferences may not satisfy formal properties. ‘Consistency’ is one of such properties, and it is associated with the transitivity property. Obviously, when carrying out a rational decision making, consistent information, i.e. information which does not imply any kind of contradiction, is more appropriate than information containing some contradictions. Therefore, in a GDM process, consistency should also be sought after. In this paper we present a consensus model for GDM problems that proceeds from consistency to consensus. This model integrates a novel consistency reaching module based on consistency measures. In particular, the model generates advice on how experts should change their preferences in order to increase their consistency. Also, the consensus model is considered adaptive because the search for consensus is adapted to the level of agreement achieved at each consensus round.
ACTIVE LEARNING WITH MISCLASSIFICATION SAMPLING BASED ON COMMITTEE
Authors: LONG JUN , YIN JIANPING , ZHU EN , ZHAO WENTAO
Published: April 2008

Active learning is an important approach to reduce data-collection costs for inductive learning problems by sampling only the most informative instances for labeling. We focus here on the sampling criterion for how to select these most informative instances. Three contributions are made in this paper. First, in contrast to the leading sampling strategy of halving the volume of version space, we present the sampling strategy of reducing the volume of version space by more than half with the assumption of target function being chosen from nonuniform distribution over version space. Second, we propose the idea of sampling the instances that would be most possibly misclassified. Third, we develop a sampling method named CBMPMS (Committee Based Most Possible Misclassification Sampling) which samples the instances that have the largest probability to be misclassified by the current classifier. Comparing the proposed CBMPMS method with the existing active learning methods, when the classifiers achieve the same accuracy, the former method will sample fewer times than the latter ones. The experiments show that the proposed method outperforms the traditional sampling methods on most selected datasets.
PERCEPTION-BASED ESTIMATIONS OF FUZZY RANDOM VARIABLES: LINEARITY AND CONVEXITY
Authors: YOSHIDA YUJI
Published: April 2008

A set of perceived random events is given by a fuzzy random variable, and an estimation of real random variables is represented by a functional on real random variables. The perception-based extension of estimation regarding random events is introduced, extending the functional to a functional of fuzzy random variables. This paper discusses some conditions and various properties of the extended estimations, for example, monotonicity, continuity, linearity, sub-additivity/super-additivity, convexity/concavity. Several examples of the perception-based extended estimations are investigated. This paper analyzes the general cases, where the estimations do not have monotone properties, from the viewpoint of convexity/concavity. The results can be applicable to other estimations in engineering, economics and so on.
ERROR DETECTION AND CORRECTION BASED ON CHINESE PHONEMIC ALPHABET IN CHINESE TEXT
Authors: HUANG CHUEN-MIN , WU MEI-CHEN , CHANG CHING-CHE
Published: April 2008

Misspelling and misconception resulting from similar pronunciation appears frequently in Chinese texts. Without double check-up, this situation will be getting worse even with the help of Chinese input editor. It is hoped that the quality of Chinese writing would be enhanced if an effective automatic error detection and correction mechanism is embedded in text editor. Therefore, the burden of manpower to proofread shall be released. Until recently, researches in automatic error detection and correction of Chinese text have undergone many challenges and suffered from bad performance compared with that of Western text. In view of the prominent phenomenon in Chinese writing problem, this study proposes a learning model based on Chinese phonemic alphabets. The experimental results demonstrate that this model is effective in finding out misspellings and further improves detection and correction rate.
Bioethical Considerations for Human Nutrigenomics
Authors: Bergmann Manuela M. , Görman Ulf , Mathers John C
Published: April 2008

This article gives an overview of the ethical issues in nutrigenomics research and personalized nutrition. The principles of research ethics, i.e., autonomy, beneficence, nonmalfeasance, and justice, are challenged by rapidly growing cross-border research activities utilizing existing and upcoming biobanks for studies of the interaction of genes with diet on risk of common diseases. We highlight the ethical issues, some unresolved, in international collaborative projects of which researchers should be aware. Personalized nutrition (tailoring diet on the basis of genotype) is one possible application of nutrigenomics research. However, until the scientific evidence concerning diet–gene interactions is much more robust, the provision of personalized dietary advice on the basis of specific genotype remains questionable. From the ethical and social perspective, nutrigenomics offers significant opportunities to improve public health by enhancing understanding of the mechanisms through which diet can be used to reduce the risk of common polygenic diseases.
Identification and Rational Design of Novel Antimicrobial Peptides for Plant Protection
Authors: Marcos Jose F. , Muñoz Alberto , Pérez-Payá Enrique , Misra Santosh , López-García Belén
Published: April 2008

Peptides and small proteins exhibiting antimicrobial activity have been isolated from many organisms ranging from insects to humans, including plants. Their role in defense is established, and their use in agriculture was already being proposed shortly after their discovery. However, some natural peptides have undesirable properties that complicate their application. Advances in peptide synthesis and high-throughput activity screening have made possible the de novo and rational design of novel peptides with improved properties. This review summarizes findings in the identification and design of short antimicrobial peptides with activity against plant pathogens, and will discuss alternatives for their heterologous production suited to plant disease control. Recent studies suggest that peptide antimicrobial action is not due solely to microbe permeation as previously described, but that more subtle factors might account for the specificity and absence of toxicity of some peptides. The elucidation of the mode of action and interaction with microbes will assist the improvement of peptide design with a view to targeting specific problems in agriculture and providing new tools for plant protection.
ATP induces guinea pig gallbladder smooth muscle excitability via the P2Y4receptor and COX-1 activity
Authors: Bartoo Aaron C. , Nelson Mark T. , Mawe Gary M.
Published: April 2008

The purpose of this study was to elucidate the mechanisms by which ATP increases guinea pig gallbladder smooth muscle (GBSM) excitability. We evaluated changes in membrane potential and action potential (AP) frequency in GBSM by use of intracellular recording. Application of ATP (100 μM) caused membrane depolarization and a significant increase in AP frequency that were not sensitive to block by tetrodotoxin (0.5 μM). The nonselective P2 antagonist, suramin (100 μM), blocked the excitatory response, resulting in decreased AP frequency in the presence of ATP. The excitatory response to ATP was not altered by pyridoxal-phosphate-6-azophenyl-2,4-disulfonic acid (30 μM), a nonselective P2X antagonist. UTP also caused membrane depolarization and increased AP frequency, with a similar dose-response relationship as ATP. RT-PCR demonstrated that the P2Y4, but not P2Y2, receptor subtype is expressed in guinea pig gallbladder muscularis. ATP induced excitation was blocked by indomethacin (10 μM) and the cyclooxygenase (COX)-1 inhibitor SC-560 (300 nM), but not the COX-2 inhibitor nimesulide (500 nM). These data suggest that ATP stimulates P2Y4receptors within the gallbladder muscularis and, in turn, stimulate prostanoid production via COX-1 leading to increased excitability of GBSM.