bluuebunny/crossref_metadata_2025 huggingface dataset:
COST ACCOUNTING AND BUSINESS ADMINISTRATION
Authors: HORWOOD O. P. F.
Published: December 2007

“I consider this subject of costs to be perhaps the most potentially fruitful field that offers itself to real economic tillers of the soil. My object is to call attention to the arduous job of clearing, draining, ploughing, harrowing and sowing that must be done before it is going to be worth while to bring out the reaper.”—C. REINOLD NOYES.1
AFRICA SOUTH OF THE SAHARA—AN ASSESSMENT OF ITS HUMAN AND MATERIAL RESOURCES1 (A REVIEW ARTICLE)
Authors: LLOYD I. S.
Published: December 2007

“The future of Africa and the relations among its races present one of the largest question marks overhanging the remainder of the 20th century.”d

“Government and semi‐government agencies will continue to be confronted with the need to finance an expanding framework of communications, power resources, irrigation, land‐clearing and the like… but a new economic potential will not emerge if the construction of this wider framework is embarked upon precipitously in advance of the necessarily more gradual growth of knowledge, experience, and of the social, communal and educational factors which all permanent advance involves.”
A TWENTY‐FIVE‐YEAR PLAN — SOME REFLECTIONS ON THE PALEY REPORT: A REVIEW ARTICLE
Authors: LLOYD I. S.
Published: December 2007

“There is no such thing as a purely domestic policy toward materials that all the world must have” : whether we discuss minerals. energy resources, timber, land or water, we face only world policies which have domestic aspects. Resources for Freedom — Chapter I, Vol. I.
“THE IDENTIFICATION PROBLEM AND THE VALIDITY OF ECONOMIC MODELS”: A COMMENT1
Authors: SMITH V. KERRY
Published: December 2007

Inasmuch as mathematical propositions refer to reality they are not certain, and inasmuch as they are certain they do not apply to reality.
REVIEW OF THE FINANCIAL AND ECONOMIC SITUATION IN SOUTH AFRICA*
Authors: JONGH Dr. T. W. DE
Published: December 2007

I have pleasure in formally presenting to you the Final Accounts of the Bank, and the Reports of the Board and the Auditors, for the year ended 31st March 1969.

I also submit to you the Bank's Annual Economic Report which describes in some detail the economic and monetary developments in South Africa during the year ended June 1969 and which in general serves as a background to my remarks today. As is customary, however, I will survey these developments very briefly before discussing the present situation and the prospects for the near future.
PROFIT MAXIMIZATION: ECONOMICS' ZOMBIE CONCEPT
Authors: BLACK STEPHEN
Published: December 2007

In the March 1969 issue of this journal Professor Rädel asked the question “Profit Maximization—Can It Be Justified?”1 The professor would appear to answer his question in the affirmative although with some reservations. The statement “would appear” is necessary because Rädel's argument does not lead to any clear, unique, answer. Since the author believes that profit maximization cannot be justified a note on Rädel's article is in order. Not being able to provide an alternative theory the author will merely attempt to demonstrate that Rädel's arguments are not valid. This seems to be potentially fruitful as Rädel considers many of the more important justifications for profit maximization.
COMPANY TAXATION*
Authors: SADIE By J. L.
Published: December 2007

To reduce the problems to be discussed to manageable proportions the taxation of mining and other special classes of companies (insurers, mutual funds, etc.) is excluded. Each of the latter constitutes a major topic, deserving of special treatment. Eschewed are also the more technical intricacies in which the administration is particularly interested.
SOME THOUGHTS ON INDIRECT TAX EFFECTS IN SOUTH AFRICA*
Authors: VAN WAASDIJK T.
Published: December 2007

Whereas income tax is the product of 19th Century thought on State revenue, indirect taxes and property taxes go back to ancient times. This is not surprising, for in underdeveloped countries consumption and property are more readily ascertained than income, which is wholly or partly received in the form of subsistence income or payment in kind.
LOCAL TAXATION IN SOUTH AFRICA
Authors: BOTHA By D. J. J.
Published: December 2007

“We are most of us profoundly uninterested in municipal affairs.” Maud.

This paper questions the rationale of the South African system of local taxation. It is argued that our system has too narrow a tax base‐fixed property‐to supply the needs of the modern city; that property taxation is iniquitous in its effects upon taxpayers; and that today it is being applied to finance categories of expenditure for which a tax on property was never intended. Some new thinking is required to devise a system that would supply a closer link between financial requirements and ability to pay.
A Black Hole in Our Galactic Center
Authors: Ruiz Michael J.
Published: December 2007

An introductory approach to black holes is presented along with astronomical observational data pertaining to the presence of a supermassive black hole at the center of our galaxy. Concepts of conservation of energy and Kepler's third law are employed so students can apply formulas from their physics class to determine the mass of the black hole that resides in the center of the Milky Way.
Escape from the Pipeline: Women Using Physics Outside Academia
Authors: Marshall Jill A.
Published: December 2007

In the last several decades the image of the leaky pipeline has become commonplace as a metaphor for the loss of women and minorities to the physics enterprise at every stage, from high school to the most advanced positions in academia. At the 2007 Winter AAPT meeting in Seattle, however, the AAPT Committee on Women in Physics sponsored a session highlighting women whose careers in physics are not faithfully represented by the pipeline model, pointing to a flaw in this way of representing women's career trajectories.
Pinhole Glasses
Authors: Colicchia Giuseppe , Hopf Martin , Wiesner Hartmut , Zollman Dean
Published: December 2007

Eye aberrations are commonly corrected by lenses that restore vision by altering rays before they pass through the cornea. Some modern promoters claim that pinhole glasses are better than conventional lenses in correcting all kinds of refractive defects such as myopia (nearsighted), hyperopia (farsighted), astigmatisms, and presbyopia. Do pinhole glasses really give better vision? Some ways to use this question for motivation in teaching optics have been discussed.1 For this column we include a series of experiments that students can complete using a model of the eye and demonstrate issues related to pinhole vision correction.
Energy and the Confused Student I: Work
Authors: Jewett John W.
Published: December 2007

Energy is a critical concept that is used in analyzing physical phenomena and is often an essential starting point in physics problem-solving. It is a global concept that appears throughout the physics curriculum in mechanics, thermodynamics, electromagnetism, and modern physics. Energy is also at the heart of descriptions of processes in biology, chemistry, astronomy, and geology. Therefore, it is important to discuss the topic of energy clearly and effectively in textbook and lecture presentations. Unfortunately, this topic is filled with possibilities for student confusion if the presentation is not carefully crafted by the instructor or the textbook. There are a number of steps, however, that can be taken in teaching about energy that reduce or eliminate the sources of confusion for students.
Tips for Organizing Your Course
Authors: Reif Marc
Published: December 2007

Column Editor's Note: If “necessity is the mother of invention,” then “desperation is the mother of organization,” says Marc Reif. Recent experiences preparing for National Board certification and teaching five different preparations of physics convinced him that keeping everything all in one place, while it may be better than nothing, does not count as organization. It's never too late to get started, so his tips for organizing will be valuable to beginning as well as experienced teachers.
Factors influencing the precision of soil seed bank estimates
Authors: Benoit D. L. , Kenkel N. C. , Cavers P. B.
Published: December 2007

The dimension of soil augers needed to sample a seed bank of Chenopodium spp. (lamb's-quarters) was determined by randomly sampling a 1.35-ha area within a cornfield in Oxford County, Ontario. Sampling units of three different auger sizes (1.9, 2.7, and 3.3 cm in diameter) were collected. On a per volume basis, there were no significant differences between the three sizes of auger in estimating the number of lamb's-quarters seeds in the soil. Three sampling methods, systematic, stratified random, and cluster, were compared with random sampling in their capacity to minimize the sampling variance. Soil cores of 1.9 cm diameter and 15 cm deep were taken systematically at 3.5-m intervals to form a 32 × 32 matrix. Repeated sampling within the matrix using Monte Carlo techniques indicated that the estimate of sampling variance decreased with increasing sample size, regardless of the sampling method used. No fewer than 60 sampling units should be collected to quantify the seed bank of an abundant weed such as lamb's-quarters. The estimates of sampling variance of systematic and cluster sampling were clearly influenced by the sampling interval and the cluster's shape, respectively. This was attributed to the underlying seed distribution of lamb's-quarters in the soil that was clustered with patterns of high and low seed density parallel to corn rows. There were no significant differences between the estimate of sampling variance of random and stratified random sampling with a fixed sample size of 64 units.
Embryo sac development in soybean: ultrastructure of megasporogenesis and early megagametogenesis
Authors: Folsom M. W. , Cass D. D.
Published: December 2007

The soybean ovule is bitegmic with the megasporocyte three to four cell layers beneath the nucellar epidermis. The megasporocyte is much larger than the surrounding nucellar cells, is connected to the nucellus by plasmodesmata, and at this stage exhibits a cytoplasmic density comparable with cells of the nucellus. After meiosis, the chalazal megaspore becomes functional in megagametogenesis. It alone retains plasmodesmatal connections to the nucellus. Chalazal megaspore expansion is accompanied by development of many small vacuoles having a uniform distribution. The first megaspore mitosis results in two nuclei lying on an axis parallel to the longitudinal axis of the embryo sac. Ultimately, these two nuclei are separated by a large vacuole. Numerous Golgi vesicles and proteinlike bodies are observed along the periphery of vacuoles in the 1-, 2-, and 4-nucleate embryo sacs. As the contents of vesicles and proteinlike bodies are observed deposited in vacuoles, it is probable that they both add osmotica to the vacuoles, thus promoting a water flux. We believe that the production of Golgi vesicles and putative protein bodies may be important in the formation and expansion of the large vacuole that appears to drive embryo sac expansion during early megagametogenesis in soybean. It is also believed that the timing to this vacuole's development has important developmental consequences.
Predicting vegetation patterns from attributes of plant growth in grassland species
Authors: Epp Gary A. , Aarssen L. W.
Published: December 2007

This study examined the relationship between vegetation patterns at three spatial scales and five plant-growth attributes that were suspected to affect competitive ability in 10 species collected from two hay field plots of different ages (cultivated in 1974 and 1984). Relative abundance of species at the plot scale (30 × 100 m) showed no relationship with any of the attributes. Species diversity within 1 × 1 m quadrats, however, had a significant negative relationship with mean seed weight in the 1984 plot and a significant negative relationship with mean plant height, mean lateral spread, mean growth rate, and "potential growth index" (combining all five attributes) in the 1974 plot. Multiple regression analysis indicated that the relationship between the five plant attributes and species diversity within the 1 × 1 m quadrats was stronger for the older (1974) (r2 = 0.67) than for the younger plot (r2 = 0.32). These data suggest that (i) the role of "competitive ability" attributes in affecting community structure becomes more evident in later stages of community development, (ii) different attributes may affect competitive ability at different stages of grassland community development, and (iii) the consequences of attribute differences among species may be revealed only in patterns at the local neighbourhood scale within vegetation. Key words: competitive ability, diversity, grassland, vegetation patterns.
Raveneliaceae revisited
Authors: Savile D. B. O.
Published: December 2007

By combining information on host ranges, biogeography, and paleoclimatology with detailed morphology, some progress has been made in understanding Raveneliaceae. Two tribes, Ravenelieae and Uropyxideae, are recognized. However, a few genera cannot be firmly assigned to a tribe, although plainly raveneliaceous, having type 5 or type 7 pycnia. By maintaining the broad family concept, all genera are at least assignable to a family. The family Pileolariaceae of Cummins and Hiratsuka is unacceptable: Pileolaria, on Anacardiaceae, is evidently allied to Uropyxideae; but Uromycladium and Atelocauda, both rusts of Acacia, belong in Ravenelieae with the other Acacia rusts. Ravenelieae evolved with Mimosoideae, mainly in the Neotropics, and all species are autoecious. Although Uropyxideae is predominantly tropical and autoecious, Tranzschelia and Leucotelium are north temperate and heteroecious. All genera of Uropyxideae are morphologically advanced. It is deduced that the early genera were heteroecious and were eradicated in times of severe aridity that broke the associations of the alternate hosts. Sphaerophragmiaceae is polyplyletic and cannot be maintained.
Gillespiea randolphensis gen. et sp.nov. (Stauropteridales), from the Upper Devonian of West Virginia
Authors: Erwin Diane M. , Rothwell Gar W.
Published: December 2007

Numerous compression – limonitized specimens of small, delicate branch systems have been discovered in the Upper Devonian Hampshire Formation near Elkins, West Virginia. The fossils are described as Gillespiea randolphensis gen. et sp.nov., and assigned to the Stauropteridales. Axes are smooth and slender, range from less than 0.1 to 1.1 mm wide, and display quadriseriate branching. The largest axes of each system bear alternating pairs of smaller lateral axes, and this pattern is repeated in all but the smallest orders of branching. All axes are protostelic, consisting of a solid xylem core with marginally mesarch protoxylem strands, a narrow zone of putative phloem, and cortex. In transverse sections, steles of larger axes are three-to four-angled and have one to three protoxylem strands at each angle. Steles of the smaller axes are elliptical or round in cross section. Small, bifurcating lateral axes that bear sporangia are attached at the levels of branching and terminate the larger systems. Megasporangia are approximately 0.6 mm long and 0.3 mm wide, and contain one or two radial, trilete megaspores. Microsporangia have not been identified. This species extends the stratigraphic range of the Stauropteridales from the Carboniferous back to the Upper Devonian and demonstrates that the group had attained the grade of extreme heterospory by the Famennian.
Nodule morphogenesis: the early infection of Alfalfa (Medicago sativa) root hairs by Rhizobium meliloti
Authors: Wood Susan M. , Newcomb William
Published: December 2007

The growth and development of alfalfa (Medicago sativa) cv. Saranac root hairs and their infection by Rhizobium meliloti strain 102F51 was studied with Smith's interference contrast optics. Uninoculated root hairs grew and matured over a 10-h growth period. The nucleus migrated from a position opposite that of root-hair protrusion at initiation to the base of the root-hair protrusion, then into the growing root hair during the most active phase. When growth was nearly complete, the nucleus assumed a position near the base of the vacuolate root hair. If root hairs were inoculated during the first 2 h of growth after initiation, either "Shepherd's crooks" or root hairs deformed into a tight curl as the tip developed. Some of these Shepherd's rooks later demonstrated typical infection-thread formation. Root hairs that were inoculated between 4 and 6 h after root-hair initiation demonstrated branched growth, with the branch forming opposite the position of the nucleus at the time of infection. Infection threads occasionally formed in either the side branches or tip branches. Root hairs that were older than 6 h at the time of inoculation formed a variety of growth deformations, including ballooning, and elongate, spatulate, spiralling, or intertwined growth. Infections in this population of root hairs were rare.
Electrical resistance measurements on young balsam fir trees in relation to specific volume increment, foliar biomass, and ion content of bark and wood
Authors: Plene H. , Thompson R. G. , McIsaac J. E. , Fensom D. S.
Published: December 2007

Electrical resistance in young balsam fir (Abiesbalsamea (L.) Mill.) trees was inversely (nonlinear) correlated with specific volume increment, total foliar biomass, and the combined weight of the current and 1-year-old foliage. These relationships were stronger before budbreak than after. No relationship existed between concentrations of N, P, K, Ca, and Mg in the bark and wood collected around time of budbreak, and electrical resistance.
Plantation white spruce mortality: estimates based on aerial photography and analysis using a life-table format
Authors: Morse Bruce W. , Kulman Herbert M.
Published: December 2007

White spruce, Piceaglauca (Moench) Voss, mortality was estimated in two 142-ha, 11- and 12-year-old plantations in north central Minnesota, using small-format color aerial photography at a scale of 1:9600 and groundplots. A double sample with regression sampling method determined mortality of trees 5 years after planting to be 3.9 ± 0.33%. Life-table analysis showed 20.7% loss during the first age interval, 0–4 years after planting. The yellow-headed spruce sawfly, Pikonemaalaskensis (Rohwer), was responsible for 65% of the mortality in the last two age intervals. Differential mortality and growth of white spruce was observed between plantations. Site preparation is suggested as a possible cause of these differences.
Chemical composition of Piceaabies and Pinussylvestris seeds under subarctic conditions
Authors: Pulliainen Erkki , Lajunen Lauri H. J.
Published: December 2007

Seeds produced by 50 Piceaabies L. and 50 Pinussylvestris L. trees near the timberline in eastern Finnish Forest Lapland were collected in late winter 1973–1981, counted, and analysed chemically (specially developed procedure with direct-current plasma emission spectrometry (DCP-AES)). Seed yields, their 1000-grain weights, and their quality varied considerably from year to year in both species, P. abies having good seed yields less often than P. sylvestris (only one good yield during the study period). The mean number of seeds produced by P. abies correlated positively with their 1000-grain weights; in P. sylvestris it did not. The nitrogen, crude fat, sugar, phosphorus, and magnesium contents correlated positively with the corresponding 1000-grain weights, suggesting that these constituents occur mainly in the endosperm and (or) embryo(s) of a seed. The crude fibre and calcium contents, however, correlated negatively with the 1000-grain weights, implying that they occur mainly in the testa. The sodium content did not increase or decrease with increasing 1000-grain weight. The composition of seeds with the same 1000-grain weight but representing yields of different years might also vary. The crude protein proportion in the P. abies seeds produced in different years varied from 9.4 to 19.3%, crude fat varied from 11.0 to 40.2%, and phosphorus varied from 0.30 to 0.83%; the corresponding ranges for P. sylvestris seeds were 10.9–30.9, 7.2–33.5, and 0.42–0.98%, respectively. Some aspects of defensive strategies of sympatric pine and spruce stands under hostile conditions at the timberline are discussed.
A growth model for red oak in New England
Authors: Hibbs David E. , Bentley William R.
Published: December 2007

Ecological, silvicultural, and financial equations were used to construct a single tree growth model for red oak (Quercusrubra L.) in New England, U.S.A. A two-phase strategy of forest management is proposed: phase l is early growth at high densities to promote rapid growth of clear boles (merchantable height); phase 2 is a series of thinnings at 10-year intervals to reduce density and so promote stem diameter growth. A dollar value per unit volume is applied to cordwood and sawlog products as a function of product size, and the combination of phase 1 and 2 lengths that maximizes net present value for a sustained series of rotations is determined. Over the range of site indexes 55 to 75, a phase l length of 45 years and total rotation length of 94 to 96 years maximizes financial returns. The trade-off in value growth between merchantable height growth and diameter growth, not the cost of precommercial thinnings, was critical to the determination of the length of phase l. Small changes in phase l length produced large changes in total returns. Rotation length was less sensitive.
Weather associated with the start of mountain pine beetle outbreaks
Authors: Thomson A. J. , Shrimpton D. M.
Published: December 2007

Extreme weather conditions associated with mountain pine beetle outbreaks were evaluated by graphical techniques for six locations throughout British Columbia. Three major associations of extreme weather patterns with lodgepole pine growth and mountain pine beetle outbreaks were identified. (i) Weather effects prior to, or early in, the growing season can reduce growth without releasing the beetle population. (ii) Weather conducive to beetle establishment and early brood development can occur too late in the season to have a noticeable effect on tree growth and therefore will not be recorded in the annual growth rings. (iii) Warm, dry periods during the summer are associated with tree growth reduction and the beginnings of outbreaks. In each of these three cases, extreme low precipitation levels were involved. Average precipitation in some months did not compensate for the effects of unfavourable extremes in other months on tree growth.
Derivation of a competitive index for individual trees from seasonal growth patterns
Authors: Smith Frederick W. , Scott David R. M.
Published: December 2007

A competitive index for lodgepole pine (Pinuscontorta Dougl.) trees in central Oregon is developed from seasonal basal area growth and an indirect estimator of foliar leaf area. Differences in seasonal basal area growth and the ratio of basal area growth to sapwood basal area between trees with and without neighbors are used to document growth reductions owing to the proximity of competing individuals. A regression between basal area growth and sapwood basal area (an estimator of leaf area) is used as a predictor of maximum potential basal area growth for trees growing free of competition. The competitive index is determined as the ratio of actual to potential basal area growth for individual trees. This index standardizes growth against differences in tree size and site conditions. Plant and soil water relations are considered as possible mechanisms of competitive interaction. Moderate minimum seasonal values of predawn leaf pressure potentials (−0.76 to −0.92 MPa) and minor differences between trees in different competitive classes led to the conclusion that soil water may not be the primary mechanism of competition on this site.
Effects of root severing treatments on loblolly pine
Authors: Carlson William C. , Harrington Constance A. , Farnum Peter , Hallgren Stephen W.
Published: December 2007

Six-year-old loblolly pine seedlings were subjected to root severing treatments varying from 0 to 100% of first-order lateral roots. Separate treatments severed surface-oriented or deep-oriented roots. Plant water status was monitored periodically for several months. After all measurements were taken, gross root system structure was determined by excavation. Treatment responses were evident on all dates of measurement. Relationships between percentage of root system cut and leaf conductance or water potential were stronger when surface-oriented roots were cut than when deep-oriented roots were cut. Severing surface-oriented first-order lateral (SOFOL) roots probably resulted in greater impact on plant water status than severing deep-oriented first-order lateral (DOFOL) roots because (i) SOFOL roots had both surface-oriented and deep-oriented second-order lateral roots that could tap both surface and subsurface soil horizons for soil moisture, and (ii) the deep-oriented second-order roots (originating from the SOFOL roots) were spatially distributed over a much larger area than the DOFOL roots and thus would have access to soil water in a larger volume of soil. For SOFOL roots the relationship between percentage cut and leaf conductance or transpiration was strongly negative; for DOFOL roots, no relationship between these variables was observed. Initially water potential decreased with the percentage of roots cut in both groups; in later measurements, water potential was affected more by severing SOFOL than DOFOL roots. Calculation of soil moisture depletion by depth indicated that both surface- and deep-oriented second-order lateral roots were important for water uptake. Severing SOFOL roots significantly decreased nitrogen, phosphorus, and potassium levels in needles of the first growth flush of the year. Levels of these elements in terminal buds were not affected by severing SOFOL roots, but were significantly reduced by severing DOFOL roots. Secondary xylem production was reduced proportionately to the amount of root system cross-sectional area severed.
A comparison of the fine root component of a pure and a mixed coniferous stand
Authors: McKay H. M. , Malcolm D. C.
Published: December 2007

Fine roots were sampled at monthly intervals during 1984–1985 in pure plots of Sitka spruce (Piceasitchensis (Bong.) Carr.) and mixed plots of Scots pine (Pinussylvestris L.) and Sitka spruce established on an upland heath in 1969. Both types of planting had received phosphorus and potassium fertiliser but no nitrogen. The mean standing crop of live roots (<2 mm diameter) in the top 5 cm of pure spruce plots was 112 g • m−2, almost double that of mixed stands (37 g • m−2 of spruce plus 20 g • m−2 of pine). Necromass was 80% of total mass in both stand types. Concentrations of nitrogen and phosphorus were greater in pure plots than in mixed plots, but fine root capital of nitrogen, phosphorus, and potassium was greater in pure spruce than in mixed plots (biomass and necromass contained 11, 2, and 5 and 45, 4, and 7 kg • ha−1 of nitrogen, phosphorus, and potassium, in pure plots, and 7, 1, and 3 and 30, 3, and 3 kg • ha−1 of nitrogen, phosphorus, and potassium in mixed plots, respectively). Production of fine roots in pure and mixed stands was estimated at 181 and 97 g • m−2•year−1 or 715 and 367 g • m−2•year−1, respectively, depending on the method of calculation. Fine roots of pure plots were highly concentrated in the top 3 cm. In mixture, spruce roots had a less extreme vertical distribution and pine roots were more evenly distributed down to 9 cm.
The vegetation of postlogged black spruce lowlands in central Canada. I. Trees and tall shrubs
Authors: Brumelis G. , Carleton T. J.
Published: December 2007

A total of 122 lowland, postlogged stands in northeastern Ontario, Canada, previously dominated by Piceamariana (Mill.) B.S.P., were surveyed for the abundance of woody species to determine the extent of natural P. mariana regeneration. Detailed information on soils, site characteristics, time since disturbance, and the type of logging was included in the survey. Stand ages ranged from 0 to 56 years since logging, and the carbon to nitrogen (C/N) ratio, used as an index of site nutrient regime, ranged from 16.2 to 60.6. The average density of trees in postlogged stands was far less than in unlogged stands on comparable sites (3050 vs. 42 000–342 000/ha). Among the logged stands, P. mariana density was highest in stands more than 20 years old and on sites with a C/N ratio greater than 40, whereas density was lowest in young stands on sites with a low C/N ratio. On sites with a C/N ratio between 25 and 35, Abiesbalsamea was the most important tree species, whereas broadleaved trees and shrubs dominated sites with a C/N ratio less than 25. In addition, broadleaved species, notably Populustremuloides, P. balsamifera, and Betulapapyrifera, achieved greater annual height growth on the sites with a low C/N ratio than did P. mariana. Twenty years before the survey marked the onset of large-scale mechanical logging. The absence of young stands with a high C/N ratio in the soil indicates that mechanical wheel skidding caused a more drastic site conversion, through disruption of the surface peat, than occurred with the earlier horse skidding practices. Mechanical logging, therefore, places fast-growing species at a competitive advantage over P. mariana by creating microsites for broadleaved seedling establishment and promoting a nutrient-enhanced substrate. These results are discussed in relation to the postfire regeneration of P. mariana and the growth strategy of the species.
Cylindrocladium root rot in Ontario bare-root nurseries: estimate of spruce seedling losses
Authors: Juzwik J. , Honhart C. , Chong N.
Published: December 2007

Estimates of cylindrocladium root rot losses in three black and three white spruce compartments at five Ontario bare-root nurseries were determined through visual field assessment and seedling isolation. The causal fungus, Cylindrocladiumfloridanum Sob. & C.P. Seym., was isolated from 10–77% of the symptomatic and 0–28% of the apparently healthy seedlings in each compartment. In five compartments, estimates of mean incidence based on seedling isolations and visual assessment, were higher than those based on visual assessment alone. The percentage of living spruce (apparently healthy or symptomatic) estimated to be infected in each compartment was 0.1–32.7%. No fungus isolations were attempted from dead seedlings. Mortality in the plots in the six compartments was 0.02–17.7%. The correlation between the level of Cylindrocladium incidence and the inoculum density was significant (p < 0.01) in two compartments. The use of inoculum density to predict disease incidence warrants further investigation.
Nutrient status and winter hardiness of red spruce foliage
Authors: Klein Richard M. , Perkins Timothy D. , Myers Helen L.
Published: December 2007

Increased ecosystem loading with inorganic nitrogen compounds derived from anthropogenic sources has been proposed to prolong vegetative growth of spruce, rendering them more susceptible to winter injury. Severely nutrient-deficient 4-year-old red spruce (Picearubens Sarg.) seedlings and adequately fertilized seedlings were provided with synthetic cloud water lacking or containing nitrate, ammonium, or both, for a full growing season, and then exposed to normal winter chilling. Needles from these seedlings were stressed at −25 or −30 °C, and freezing injury was measured as ion leakage. Cloud water condensates had no effect on hardiness of needles of either nutrient status. Initially nutrient-sufficient seedlings transferred to nutrient-deficient conditions also exhibited no change in hardiness. Severely nutrient-deficient seedlings had needles that were significantly more sensitive to winter injury than seedlings under nutrient-sufficient conditions. Improving the nutrient status of initially nitrogen-deficient seedlings reduced their sensitivity to freezing injury. Based upon experimental results and consideration of the amounts of inorganic nitrogen reaching upper-elevation conifer forests, there is no evidence to support the hypothesis that anthropogenic nitrogen supplies significantly reduce winter hardiness of spruce foliage. It is improbable that winter injury due to elevated anthropogenic nitrogen is a causal factor in contemporary forest decline.
Influence of short-term atmospheric CO2 enrichment on growth, allocation patterns, and biochemistry of black spruce seedlings at different stages of development
Authors: Campagna Michel A. , Margolis Hank A.
Published: December 2007

Black spruce seedlings (Piceamariana Mill.) were exposed to either elevated (1000 ppm) or ambient (340 ppm) atmospheric CO2 levels at different stages of seedling development over a winter greenhouse production cycle. Seedlings germinated in early February and were placed in CO2 chambers for either 3 or 6 weeks during March, April, May, or August. Total seedling biomass increased under high CO2 conditions for the March, April, and May stages of development, but showed no significant response in August. The greater part of the CO2 response occurred during the second 3 weeks of exposure in March and April but during the first 3 weeks of exposure in May. In September, those seedlings exposed to CO2 in April and May had 30 and 14%, respectively, greater biomass than control seedlings, but seedlings from the other stages of development no longer had significant differences remaining from the CO2 treatment. This suggests that it could be very efficient to give a short well-timed CO2 pulse at the beginning of the production cycle in hopes of producing a size difference that is maintained throughout the remainder of the greenhouse production cycle under ambient levels of CO2. Short-term exposure to elevated CO2 also increased the ratio of shoot dry weight to total height for the March, April, and May stages of development. The ratio of total nonstructural carbohydrates to free amino acids was negatively correlated (r2 = 0.98) with the allocation of new growth between shoots and roots as measured by the allocation coefficient, k (milligrams shoot growth per milligrams root growth). As seedlings developed along their seasonal growth cycle, ratios of total nonstructural carbohydrates to free amino acids increased and the values for k decreased. The effect of CO2 enrichment on these two factors is discussed. Monitoring total nonstructural carbohydrate and free amino acid concentrations in foliage could have potential as a method to predict the percentage of carbon allocated to root systems of entire forest stands as well as of individual tree seedlings.
Forecasting diurnal variations in meteorological parameters for predicting fire behaviour
Authors: Beck J. A. , Trevitt A. C. F.
Published: December 2007

Empirical models for predicting diurnal variations in air temperature, wind speed, and relative humidity, given daily maximum and minimum values, latitude, and Julian date, have been developed. Solar heating during the daytime is quantitatively depicted using a truncated sine function, and nighttime cooling is characterized by an exponential decay function. Daily wind-speed trends echo diurnal temperature patterns, and relative humidity is modelled as a function of temperature by assuming that absolute humidity remains constant throughout the day. The time of occurrence of daily maxima and minima in temperature and wind speed varies seasonally according to changes in day length. Maximum temperature and wind speed typically occur later in the day than the maximum solar insolation. The magnitude of this lag depends on both time of year and latitude. The models were parameterized for two locations in Australia and observed, and modelled variations in temperature, relative humidity, and wind speed were used to forecast diurnal trends in fire behaviour. Predicted fire behaviour compared favourably in the two cases considering the very simple modelling approach employed.
Modelling seasonal variation in daily people-caused forest fire occurrence
Authors: Martell D. L. , Bevilacqua E. , Stocks B. J.
Published: December 2007

Periodic functions of Julian calendar dates were used to incorporate seasonal variation into logistic regression models designed to predict daily people-caused forest fire occurrence in the Northern Region of the province of Ontario. Three years of independent test data were used to evaluate predictions produced by the models.
Soil affects Armillaria root rot of lodgepole pine
Authors: Blenis Peter V. , Mugala Martin S. , Hiratsuka Yasuyuki
Published: December 2007

A total of 768 two-year-old lodgepole pine (Pinuscontorta var. latifolia Engelm.) seedlings were transplanted into four different soils, having different capabilities for supporting lodgepole pine growth. Thirty days later, they were inoculated with either of two isolates of North American Biological Species I (Armillariaostoyae (Romag.) Herink) of Armillaria. Log–linear analysis indicated that soil type had a significant effect on inoculum viability, rhizomorph production, frequency of seedling infection, and the likelihood of tree death following infection.
Effects of temperature regime and fertilization on nitrogenase activity of black alder seedlings during autumn in Illinois, U.S.A.
Authors: Côté Benoît , Dawson Jeffrey O.
Published: December 2007

A pot experiment was conducted to determine the effects of two regimes of temperature and fertilization on nitrogenase activity (acetylene reduction) of naturalized black alder (Alnusglutinosa (L.) Gaertn.) seedlings during autumn in central Illinois, United States. An equal number of Frankia-nodulated plants were fertilized with either a complete or a nitrogen-free fertilizer solution. After 3 months of growth in a glasshouse, half of the plants in each fertilization group were transferred outside in mid-September. Rates of C2H2 reduction decreased throughout autumn for plants in all treatments, although exposure to freezing temperatures accelerated the decline of nitrogenase activity. Alders that did not receive nitrogen fertilization were still reducing C2H2 under natural light conditions in the heated glasshouse on December 10 at a rate of 7.5 nmol•mg−1•h−1. Compared with alders not receiving mineral nitrogen, complete fertilization resulted in a 45% reduction of initial autumnal rates of C2H2 reduction and early inactivity of nitrogenase. Leaf senescence and leaf abscission of naturalized black alder were not induced by decreasing photoperiod alone in Illinois. We conclude that N2 fixation of black alder in Illinois can proceed late into the autumn as long as green leaves remain attached to the plant and nodules are not subjected to low and freezing temperatures.
NONLINEAR OPTICAL WAVEGUIDE STRUCTURE FOR SENSOR APPLICATION: TM CASE
Authors: KHALIL HALA M. , SHABAT MOHAMMED M. , TAYA SOFYAN A. , ABADLA MAZEN M.
Published: December 2007

In this work, we present an extensive theoretical analysis of nonlinear optical waveguide sensor. The waveguide under consideration consists of a thin dielectrica film surrounded by a self-focused nonlinear cladding and a linear substrate. The nonlinearity of the cladding is considered to be of Kerr-type. Both cases, when the effective refractive index is greater and when it is smaller than the index of the guiding layer, are discussed. The sensitivity of the effective refractive index to any change in the cladding index in evanescent optical waveguide sensor is derived for TM modes. Closed form analytical expressions and normalized charts are given to provide the conditions required for the sensor to exhibit its maximum sensitivity. The results are compared with those of the well-known linear evanescent waveguide sensors.
CLUSTERING USING AN IMPROVED HYBRID GENETIC ALGORITHM
Authors: LIU YONGGUO , PU XIAORONG , SHEN YIDONG , YI ZHANG , LIAO XIAOFENG
Published: December 2007

In this article, a new genetic clustering algorithm called the Improved Hybrid Genetic Clustering Algorithm (IHGCA) is proposed to deal with the clustering problem under the criterion of minimum sum of squares clustering. In IHGCA, the improvement operation including five local iteration methods is developed to tune the individual and accelerate the convergence speed of the clustering algorithm, and the partition-absorption mutation operation is designed to reassign objects among different clusters. By experimental simulations, its superiority over some known genetic clustering methods is demonstrated.
LARGE SCALE MULTIKERNEL RELEVANCE VECTOR MACHINE FOR OBJECT DETECTION
Authors: TZIKAS DIMITRIS , LIKAS ARISTIDIS , GALATSANOS NIKOLAS
Published: December 2007

The Relevance Vector Machine(RVM) is a widely accepted Bayesian model commonly used for regression and classification tasks. In this paper we propose a multikernel version of the RVM and present an alternative inference algorithm based on Fourier domain computation to solve this model for large scale problems, e.g. images. We then apply the proposed method to the object detection problem with promising results.
WORDS VERSUS CHARACTER N-GRAMS FOR ANTI-SPAM FILTERING
Authors: KANARIS IOANNIS , KANARIS KONSTANTINOS , HOUVARDAS IOANNIS , STAMATATOS EFSTATHIOS
Published: December 2007

The increasing number of unsolicited e-mail messages (spam) reveals the need for the development of reliable anti-spam filters. The vast majority of content-based techniques rely on word-based representation of messages. Such approaches require reliable tokenizers for detecting the token boundaries. As a consequence, a common practice of spammers is to attempt to confuse tokenizers using unexpected punctuation marks or special characters within the message. In this paper we explore an alternative low-level representation based on character n-grams which avoids the use of tokenizers and other language-dependent tools. Based on experiments on two well-known benchmark corpora and a variety of evaluation measures, we show that character n-grams are more reliable features than word-tokens despite the fact that they increase the dimensionality of the problem. Moreover, we propose a method for extracting variable-length n-grams which produces optimal classifiers among the examined models under cost-sensitive evaluation.
A LARGE INTRA-ARTICULAR LOOSE BODY IN THE METACARPOPHALANGEAL JOINT OF THE MIDDLE FINGER MIMICKING A CALCIFIED TUMOROUS LESION: A CASE REPORT
Authors: Ebihara Goro , Ikeda Masayoshi , Oka Yoshinori
Published: December 2007

We will report on a case with a large intra-articular loose body in the metacarpophalangeal (MP) joint of the middle finger in a 30-year-old-male, which was mimicking a calcified tumourous lesion adjacent to the palmar side of the metacarpal head. It was easily removed through the palmar approach.
The Messinian ‘Vena del Gesso’ evaporites revisited: characterization of isotopic composition and organic matter
Authors: Lugli S. , Bassetti M. A. , Manzi V. , Barbieri M. , Longinelli A. , Roveri M.
Published: December 2007

The ‘Vena del Gesso’ (Gessoso-Solfifera Fm, Messinian) is a 227 m-thick ridge along the western Romagna Apennines (Italy) consisting of up to 16 selenite cycles separated by shales and minor carbonate. The total organic carbon values of these deposits range between 0.087–0.016% (gypsum) and 3% (shales). Organic matter is dominated by black debris associated with continental debris. Algae and dynocysts are rare (<1%). The amount of amorphous organic matter is low but it may reach up to
c.
40%. The
87
Sr/
86
Sr of gypsum and carbonate vary from 0.708890 to 0.709024, yielding non-oceanic values with several exceptions that plot within error of coeval oceanic values only in the upper part of the section (from the 6° bed). The sulphur isotope composition of gypsum range between δ
34
S =+21.8 and +23.7‰ and may represent precipitation of δ
34
S-enriched gypsum due to the fractionation effect or recycling of coeval gypsum with contributions of brine-sediment redox variations. The isotope values of carbonates show a large variability (−6.4<δ
18
O<+6.05‰; −14.68<δ
13
C<+2.5‰), suggesting a complex origin by mixing of marine and non-marine waters with a significant contribution of reduced organic matter. These data point to an evaporite basin dominated by continental waters which received significant phases of marine recharge in the upper part together with a marked facies change. Because seawater recharges and a similar facies change are present in other Messinian sections, it follows that we have new possible geochemical and facies markers to correlate the Lower Evaporites across the Mediterranean.
Sedimentology and geochemistry of the Middle Miocene (Badenian) salt-bearing succession from East Slovakian Basin (Zbudza Formation)
Authors: Bukowski K. , Czapowski G. , Karoli S. , BĄbel M.
Published: December 2007

The Middle Miocene (Badenian) evaporites have formed within more or less restricted basins, occupying the Carpathian Foredeep and inner depressions in the East Slovakian Basin of the Carpathians. Their deposition coincided with the increased tectonic activity in the Carpathians, evidenced by volcanic eruptions (widespread volcaniclastics) and frequent earthquakes. These phenomena apparently initiated landslides, submarine slumps and turbidity currents which formed deposits characterized by rapid facies changes and relatively limited lateral continuity. The clastic–evaporitic deposition in the Zbudza area (East Slovakian Basin) was controlled by frequent tectonic and seismic phenomena and high continental clastic supply that produced repeated slump sediments with dominant proximal mass flows and distal flows and diverse salt types (salt/clay rhythmites, finer halite–arenites, coarse halite–rudites). These zones are separated by primary salt units (halite) precipitated
in situ
from bottom brines during calm periods. The observed cyclicity (I–V cycles) reflects varied tectonic activity of the basin margins, that mechanically remobilized the sediments from marginal salt pans, flats and adjacent uplifts, and could be correlable with cycles in the Wieliczka Formation from Carpathian Foredeep.
Sulphur isotopic composition of K–Mg sulphates of the Miocene evaporites of the Carpathian Foredeep, Ukraine
Authors: Hryniv S. , Parafiniuk J. , Peryt T. M.
Published: December 2007

Miocene evaporites of the Carpathian Foredeep host an interesting sulphates group of potash deposits, including about 20 sulphates minerals. The study of sulphur isotopic composition of 10 of the sulphates minerals from the Kalush–Holyh and Stebnyk potash deposits shows that only the basal Ca-sulphates (anhydrite) from the Kalush–Holyn potash deposits has
δ
34
S values typical of Neogene marine evaporites (+21.0‰). Potash minerals related to the deposits (polyhalite, anhydrite, kainite, langbeinite and kieserite) show
δ
34
S values from +15.28‰ to +17.54‰, and the weathering zone minerals (picromerite, leonite, bloedite, syngenite and gypsum) show values ranging from +14.73‰ to +18.22‰. The recorded depletion of sulphur isotopic composition of the salt minerals of potash deposits (and their weathering zone) was probably caused by one or more of the following isotope fractionation factors: bacterial reduction of sulphate, effect of crystallization and inflow of surface waters containing sulphates enriched in light sulphur isotopes due to pyrite oxidation. Accordingly, the observed sulphur isotopic composition of minerals from these potash deposits demonstrates the depletion of the original brines and continual inflow of new (concentrated) seawater. Similar sulphur isotopic composition of minerals from the potash deposits and their weathering zone points out that there was no significant sulphur isotope fractionation during weathering and in this case inflow of surface water has an insignificant influence on sulphur isotopic composition.