bluuebunny/crossref_metadata_2025 huggingface dataset:
An introduction to the Barell body region by nature of injury diagnosis matrix
Authors: Barell V , Aharonson-Daniel L , Fingerhut L A , Mackenzie E J , Ziv A , Boyko V , Abargel A , Avitzour M , Heruti R
Published: October 2002

Introduction:The Barell body region by nature of injury diagnosis matrix standardizes data selection and reports, using a two dimensional array (matrix) that includes allInternational Classification of Diseases(ICD)-9-CM codes describing trauma.

Aim:To provide a standard format for reports from trauma registries, hospital discharge data systems, emergency department data systems, or other sources of non-fatal injury data. This tool could also be used to characterize the patterns of injury using a manageable number of clinically meaningful diagnostic categories and to serve as a standard for casemix comparison across time and place.

Concept:The matrix displays 12 nature of injury columns and 36 body region rows placing each ICD-9-CM code in the range from 800 to 995 in a unique cell location in the matrix. Each cell includes the codes associated with a given injury. The matrix rows and columns can easily be collapsed to get broader groupings or expanded if more specific sites are required. The current matrix offers three standard levels of detail through predefined collapsing of body regions from 36 rows to nine rows to five rows.

Matrix development:This paper presents stages in the development and the major concepts and properties of the matrix, using data from the Israeli national trauma registry, and from the US National Hospital Discharge Survey. The matrix introduces new ideas such as the separation of traumatic brain injury (TBI), into three types. Injuries to the eye have been separated from other facial injuries. Other head injuries such as open wounds and burns were categorized separately. Injuries to the spinal cord and spinal column were also separated as are the abdomen and pelvis. Extremities have been divided into upper and lower with a further subdivision into more specific regions. Hip fractures were separated from other lower extremity fractures.

Forthcoming developments:The matrix will be used for the development of standard methods for the analysis of multiple injuries and the creation of patient injury profiles. To meet the growing use of ICD-10 and to be applicable to a wider range of countries, the matrix will be translated to ICD-10 and eventually to ICD-10-CM.

Conclusion:The Barell injury diagnosis matrix has the potential to serve as a basic tool in epidemiological and clinical analyses of injury data.
Grasping the nettle—what to do when patients withdraw their consent for treatment: (a clinical perspective on the case of Ms B)
Authors: Tweeddale M G
Published: October 2002

Withdrawal of active treatment is common in medical practice, especially in critical care medicine. Usually, however, it involves patients who are unable to take part in the decision making process. As the case of Ms B shows, doctors are sometimes reluctant to withdraw active treatment when the patient is awake and requesting such a course of action. In theory, having a competent patient should facilitate clinical decision making, so where does the problem arise? It is argued that latent medical paternalism may come to the surface when doctors are asked by patients to follow a course of action which is in conflict with their own perspective.
Assessment of the exposure of islanders to ash from the Soufriere Hills volcano, Montserrat, British West Indies
Authors: Searl A , Nicholl A , Baxter P J
Published: October 2002

Background and Aims:The Soufriere Hills volcano, Montserrat, has been erupting since July 1995 and volcanic ash has fallen on the island throughout most of the eruption. The ash contains substantial quantities of respirable particles and unusually large amounts (15–20%) of the crystalline silica mineral, cristobalite. The purpose of the surveys described here, undertaken between December 1996 and April 2000, was to determine levels of personal exposure of islanders to volcanic ash and cristobalite in order to inform advice on the associated risks to health and the measures required to reduce exposure.

Methods:Surveys of personal exposure to respirable dust and cristobalite were undertaken using cyclone samplers. In addition, direct reading instruments (DUSTTRAK) were used to monitor ambient air concentrations of PM10at fixed sites and also to provide information about exposures to airborne particles associated with selected activities.

Results:Environmental concentrations of airborne ash have been greatest in the areas where the most ash has been deposited and during dry weather. Individual exposure to airborne ash was related to occupation, with the highest exposures among gardeners, cleaners, roadworkers, and police at roadside checkpoints. During 1997 many of these individuals were exposed to concentrations of cristobalite that exceeded the ACGIH recommended occupational exposure limit. Since the population became confined to the north of the island in October 1997, even those in relatively dusty occupations have received exposures to cristobalite well below this limit.

Conclusions:Most of the 4500 people who have remained on island since the eruption began have not been exposed to sufficiently high concentrations of airborne dust for long enough to be at risk of developing silicosis. However, more than a dozen individuals continued to experience frequent high occupational exposures to volcanic ash, some of whom may have had sufficient exposure to crystalline silica to be at risk of developing mild silicosis. If volcanic activity were to deposit further ash over the occupied areas of the island during the coming years, the risks of silicosis will become more substantial.
Chronic neck and shoulder pain, age, and working conditions: longitudinal results from a large random sample in France
Authors: Cassou B , Derriennic F , Monfort C , Norton J , Touranchet A
Published: October 2002

Aims:To analyse the effects of age and occupational factors on both the incidence and the disappearance of chronic neck and shoulder pain after a five year follow up period.

Methods:A prospective longitudinal investigation (ESTEV) was carried out in 1990 and 1995 in seven regions of France. A random sample of male and female workers born in 1938, 1943, 1948, and 1953 was selected from the occupational physicians’ files. In 1990, 21 378 subjects were interviewed (88% of those contacted), and 87% were interviewed again in 1995. Chronic neck and shoulder pain satisfying specific criteria, and psychosocial working conditions were investigated by a structured self administered questionnaire and a clinical examination.

Results:Prevalence (men 7.8%, women 14.8% in 1990) and incidence (men 7.3%, women 12.5% for the period 1990–95) of chronic neck and shoulder pain increased with age, and were more frequent among women than men in every birth cohort. The disappearance rate of chronic neck and shoulder pain decreased with age. Some adverse working conditions (repetitive work under time constraints, awkward work for men, repetitive work for women) contributed to the development of these disorders, independently of age. Psychosocial factors seemed to play a role in both the development and disappearance of chronic neck and shoulder pain. Data did not show specific interactions between age and working conditions.

Conclusions:The aging of the workforce appears to contribute to the widespread concern about chronic neck and shoulder pain. A better understanding of work activity regulation of older workers can open up new preventive prospects.
Oral candidiasis
Authors: Akpan A , Morgan R
Published: October 2002

Oral candidiasis is a common opportunistic infection of the oral cavity caused by an overgrowth of Candida species, the commonest being Candida albicans. The incidence varies depending on age and certain predisposing factors. There are three broad groupings consisting of acute candidiasis, chronic candidiasis, and angular cheilitis. Risk factors include impaired salivary gland function, drugs, dentures, high carbohydrate diet, and extremes of life, smoking, diabetes mellitus, Cushing’s syndrome, malignancies, and immunosuppressive conditions. Management involves taking a history, an examination, and appropriate antifungal treatment with a few requiring samples to be taken for laboratory analysis. In certain high risk groups antifungal prophylaxis reduces the incidence and severity of infections. The prognosis is good in the great majority of cases.
Patient recall of medication details in the outpatient clinic. Audit and assessment of the value of printed instructions requesting patients to bring medications to clinic
Authors: Keeble W , Cobbe S M
Published: October 2002

Objective

There is no ambiguity when a patient presents their medications in the correct packaging during a consultation and declares, “this is what I am taking, doctor, I take this many, at this time”. The aim of this study was to establish the prevalence of consultations in which patients attend both “empty handed” and unsure of their treatment. A re-evaluation was made after a simple intervention.

Design

Prospective cross sectional study with subsequent intervention and re-evaluation based on patient completed questionnaire.

Setting

University hospital cardiology outpatient department.

Patients

Consecutive patients arriving at clinic reception desks.

Results

Altogether 774 of 857 patients were receiving treatment; 15% attended with their tablets and 28% provided a note of their medication in some form; 40% attended empty handed but confident they could recall all aspects of their treatment from memory; 17% attended empty handed and unsure of their treatment.

Intervention

Clinic appointment cards were stamped with the request PLEASE BRING YOUR MEDICATIONS WITH YOU TO THE CARDIOLOGY CLINIC. A second unrelated cohort of patients was then surveyed in an identical manner, nine months later. Of these, 329 of 376 patients were receiving medication. Those attending with their tablets in hand now accounted for 78% rather than 15% (χ2=423, df=2, p<0.001). The group unsure of their treatment, but attending empty handed, fell from 17% to 2%.

Conclusions

Reprinted appointment cards are highly successful in encouraging patients to attend with their tablets. This provides reliable information for decision making.
Regional hydrogeochemistry of the carbonate rock aquifer, southern Manitoba
Authors: Grasby Stephen E , Betcher Robert N
Published: October 2002

Middle Ordovician to Middle Devonian carbonates in the Manitoba lowlands form an extensive aquifer system along the eastern edge of the Williston Basin. The aquifer is divided into fresh and saline portions by a series of topographic lows defined by major river systems and lakes that create a northsouth-trending hydraulic divide. East of this divide CaMgHCO3 fresh waters are derived by active modern-day recharge focused in the Sandilands and Interlake regions. Stable isotope and geochemical data indicate that NaCl saline waters west of the divide are a mixture of original basin brines and glacial melt water pushed into the basin during Pleistocene glaciation. High Na/Cl and Cl/Br ratios are consistent with significant salt dissolution by glacial melt water.
U-Pb ages of plutonism, wollastonite formation, and deformation in the central part of the Lac-Saint-Jean anorthosite suite
Authors: Higgins Michael D , Ider Mohcine , Breemen Otto van
Published: October 2002

The Lac-Saint-Jean anorthosite suite (LSJAS) is the largest ensemble of plutons in the Grenville Province. Zircons from a pluton in the central part of the LSJAS yield an age of 1140+105 Ma, which accords with existing 11571142 Ma ages determined from the southern part of the LSJAS. The Du Bras granite is a linear pluton emplaced into the dominantly dextral Pipmuacan shear zone (PSZ). The UPb zircon age of 1148 ± 2 Ma for the Du Bras granite confirms earlier proposals that it is a granophyre, formed at greater depths by partial melting of paragneiss by the heat of the crystallizing anorthosite. Parts of the pluton are strongly deformed by the shear zone, and other parts cut the shear zone. This suggests that the pluton dates one phase of movement of the PSZ. The Canton-St-Onge wollastonite deposit was developed in paragneisses preserved within the PSZ. Titanite from this deposit gives an age of 1163 ± 18 Ma, identical within error to that of the Du Bras granite, indicating that this pluton may have provided the skarn fluids. A second plutonic cycle comprises the post-tectonic Astra granite, which stitches the PSZ, and an amazonite-bearing pegmatite dyke. Zircons gave an age of 1028 ± 2 Ma for the Astra granite. The amazonite-bearing dyke only yielded monazite, one fraction of which gave an age similar to that of the Astra granite. Other fractions record the effects of a thermal event at 10201017 Ma that may be related to a widespread magmatic event. The undeformed Venus de Milot syenitic intrusion yields a UPb age of 988 ± 2 Ma. It was emplaced along the northwest-trending Lac Rioux fault, indicating that one phase of movement occurred before 988 Ma. Another strand of the same fault system also cuts the intrusion, showing later reactivation that may have been associated with the formation of the Saguenay Graben.
Modelling the effects of establishing a marine reserve for mobile fish species
Authors: Apostolaki P , Milner-Gulland E J , McAllister M K , Kirkwood G P
Published: October 2002

We present a model of the effects of a marine reserve on spawning stock biomass (SSB) and short- and long-term yield for a size-structured species that exhibits seasonal movements. The model considers the effects of protecting nursery and (or) spawning grounds under a range of fishing mortalities and fish mobility rates. We consider two extremes of effort redistribution following reserve establishment and analyze the effects of a reserve when the fishery targets either mature or immature fish. We apply the model to the Mediterranean hake (Merluccius merluccius) and show that a marine reserve could be highly beneficial for this species. We demonstrate benefits from reserves not just for overexploited stocks of low-mobility species, but also (to a lesser extent) for underexploited stocks and high-mobility species. Greatly increased resilience to overfishing is also found in the majority of cases. We show that a reserve provides benefits additional to those obtained from simple effort control. Benefits from reserves depend to a major extent on the amount of effort redistribution following reserve establishment and on fishing selectivity; hence, these factors should be key components of any evaluation of reserve effectiveness.
Perspectives on the age and distribution of large wood in riparian carbon pools
Authors: Guyette Richard P , Cole William G , Dey Daniel C , Muzika Rose-Marie
Published: October 2002

Most knowledge of carbon budgets is derived from the productivity and sequestration of carbon in terrestrial and marine ecosystems. Less is known of carbon stored in riparian areas associated with lakes and rivers. Case studies of the age distribution of carbon in aquatic large wood (Clw) from two different landscapes with different drainage patterns were established using tree-ring and14C dating. Cumulative negative exponential distributions of the age of Clwranged over periods from 1000 to 9485 years. Large woody debris had mean residence times of 261 years in small oligotrophic lakes and 350800 years in a stream reach. Large wood can reside for an order of magnitude longer in freshwaterriparian ecosystems than in comparable above-ground terrestrial ecosystems. Although riparian areas make up only a small fraction of most landscapes, they may account for a relatively larger proportion of aged Clwthan is stored above ground in terrestrial ecosystems.
The food-unlimited growth rate of Atlantic cod (Gadus morhua)
Authors: Björnsson Björn , Steinarsson Agnar
Published: October 2002

Results from laboratory experiments showed that food-unlimited growth rate (G) of Atlantic cod (Gadus morhua) declined linearly with fish weight (W) on a loglog scale at six different temperatures: 2, 4, 7, 10, 13, and 16°C. The intercept (αi) and slope (βi) of these regressions increased linearly with temperature (T), implying that G = αi W βi, where αi = γ1 + δ1T and βi = γ2 + δ2T. Nonlinear fit of the four-parameter model showed that γ1 was not significantly different from 0, and thus the following three-parameter model is suggested for the food-unlimited growth rate of cod ranging in size from 2 to 5000 g at any temperature from 2 to 16°C: G = (0.5735T)W(0.19340.02001T). The results indicate that temperature in this size range has a much greater effect on the growth rate of small juvenile cod than on that of larger cod. The model predicts that the optimal temperature for growth of cod decreases with increased size of fish, from 14.3°C for 50-g fish to 5.9°C for 5000-g fish. Growth curves were derived for cod at constant and seasonally variable temperatures. Weight-at-age was calculated for different temperatures.
Increased metabolic cost of swimming and consequent alterations to circadian activity in rainbow trout (Oncorhynchus mykiss) exposed to dietary copper
Authors: Campbell H A , Handy R D , Sims D W
Published: October 2002

This study tests the hypothesis that rainbow trout (Oncorhynchus mykiss) compensate for the metabolic cost of dietary Cu exposure by reducing swimming activity at particular times during the diel cycle. Fish were exposed to excess dietary Cu for three months (726 mg Cu·kg1dry weight) and simultaneously oxygen consumption (MO2) and spontaneous swimming activity were measured. Rhythmicity in swimming activity was examined by videorecording fish behaviours for 48 h. Standard metabolic rate estimates (RS) of 7.2 and 8.7 mmol O2·kg1·h1(15°C) were measured for control and Cu-exposed fish, respectively. MO2was higher in Cu-exposed fish at any chosen speed compared with control Cu-exposed trout, which decreased activity (mean speed) by at least 75%, spent more time at lower speeds, and lost circadian periodicity in these parameters compared with controls. Mean growth rates were normal, although Cu-exposed fish showed a narrower range of body weights and fewer mortalities than control groups, suggesting a suppression in social behaviour in Cu-exposed fish. Overall, the increased metabolic cost of swimming in Cu-exposed fish was fully compensated by a reduction in activity, particularly at night and dawn. However, this behavioural strategy suggests that spatial and temporal aspects of ecologically important social behaviours may be compromised in Cu-exposed fish.
Coho salmon (Oncorhynchus kisutch) ocean migration patterns: insight from marine coded-wire tag recoveries
Authors: Weitkamp Laurie , Neely Kathleen
Published: October 2002

We investigated geographic variation in the ocean migration of coho salmon (Oncorhynchus kisutch) by examining recovery locations of 1.77 million coded-wire tagged fish from 90 hatcheries and 36 wild populations along the west coast of North America. Principal component, cluster, and similarity analyses were used to reveal both large- and small-scale variation in marine recovery patterns. We identified 12 distinct ocean distribution patterns, each associated with a particular geographic region. Despite these distinct patterns, however, fish from a given population were widely dispersed in the coastal ocean. Recovery patterns for tagged wild populations were consistent with those of hatchery populations from the same region, suggesting that marine distributions based on hatchery populations are reasonable proxies for distributions of wild populations. These region-specific distribution patterns suggest unappreciated life history diversity for coho salmon in the marine environment. When combined with region-specific adult size variation, they suggest migratory differences earlier in the ocean residence period as well. These results provide a novel framework with which to view geographic variation in salmon ocean ecology, conservation, and management.
The Baltica sea of invaders
Authors: Leppäkoski Erkki , Gollasch Stephan , Gruszka Piotr , Ojaveer Henn , Olenin Sergej , Panov Vadim
Published: October 2002

There are about 100 nonindigenous species recorded in the Baltic Sea. Invasive species have resulted in major changes in nearshore ecosystems, especially in coastal lagoons and inlets that can be identified as "centres of xenodiversity". Fewer than 70 of these species have established reproducing populations. Dominant invasion vectors include unintentional introductions via ballast water, tank sediments, and hull fouling, aquaculture, and the construction of canals that have facilitated active or passive natural dispersal. Of the approximately 60 unintentionally introduced species with a known invasion history, 38 are transoceanic (including 19 Atlantic species of American origin) and 18 of Ponto-Caspian origin. Species that have caused economic damage to fisheries, shipping, and industry include the hydrozoan Cordylophora caspia, the barnacle Balanus improvisus, the cladoceran Cercopagis pengoi, and the bivalve Dreissena polymorpha. The Baltic Sea has served as a secondary source of nonindigenous species to the North American Great Lakes. Further study is warranted to quantify large-scale ecosystem changes in the Baltic associated with establishment and population growth of nonindigenous species and to prevent future invasions.
Nouvelle approche pour déterminer la distribution des temps de séjour dans les réservoirs d'eau potable en régime non permanent
Authors: Mainville Éric , Gauthier Vincent , Lavallée Daniel , Marche Claude
Published: October 2002

Drinking water storage tanks are used to respond to fluctuating demand and to maintain water pressure in the distribution network. In drinking water plants, they are also used for disinfection. In both cases, a good knowledge of the residence time distribution (RTD) is important. An easy way to obtain the water RTD in a drinking water tank is to perform a tracer study. Nevertheless, "classical" tracing techniques can only be used under steady flow conditions. To cope with that, this study proposes a new approach to extend the application of tracer tests to unsteady flow conditions. This new approach is based on signal processing. It has been tested numerically and on a pilot scale model. The numerical tests have shown that this technique can be used for determining the RTD twice more rapidly than the "classical" methods. Thus, this technique allows to approach the knowledge of the RTD under unsteady flow conditions. Pilot scale tests have shown the need for other improvements to bring the quality of the results obtained to the same level of goodness as those obtained from a theorical example.Key words: drinking water, storage tanks, water quality, tracer study, residence time distribution, signal processing, unsteady flow.
Absolute wavelength measurement of the Lyman-α transition of hydrogen-like silicon
Authors: Tschischgale J , Klöpfel D , Beiersdorfer P , Brown G V , Förster E , Schulte-Schrepping H , Utter S B
Published: October 2002

The wavelengths of the 1s1/22p1/2 and 1s1/22p3/2 Lyman-α transitions have been measured in hydrogenic silicon with an accuracy of 70 ppm. The measurement was carried out with an electron-beam ion trap with a calibrated double-faced monolithic crystal that enabled absolute measurements of the transition wavelengths. The values for the Lyman-α wavelengths are λLyα1 = 6.180 49(44) Å and λLyα2 = 6.185 56(66) Å. The wavelengths are in good agreement with calculations and allow a determination of the 1s Lamb shift to within 28% in a region that has received little experimental attention. PACS Nos.:32.30Rj, 31.30Jv
Excited states of two-dimensional excitons in quantum wells
Authors: Varshni Y P
Published: October 2002

The energies of ten excited states of screened two-dimensional excitons in a semiconducting quantum-well structure are calculated as a function of the screening parameter qs by the WKB method. The screening of the Coulomb interaction between the electronhole pair by the free carriers present is taken into account by using the screened potential obtained by Stern and Howard (1967). The energies of the excited states are found to decrease with increasing values of the screening parameter qs in all cases. Further the levels become unbound at finite values of the screening parameter. Critical screening parameters are estimated for the ten states. PACS Nos.: 73.21Fg, 78.67De, 71.35-y, 71.35Cc
Particle production in central PbPb collisions at high energy
Authors: Liu F -H
Published: October 2002

The rapidity and transverse-momentum distributions of particles produced in central PbPb collisions at high energy are analyzed by the thermalized cylinder model. The calculated results are compared and found to be in agreement with the recent experimental data of the NA49 Collaboration.

PACS Nos.: 25.75-q, 24.10Pa
Stueckelberg mechanism for antisymmetric tensor fields
Authors: Kuzmin S V , McKeon D.G.C.
Published: October 2002

It is shown how vector Stueckelberg fields can be introduced to ensure gauge invariance for mass terms for an antisymmetric tensor field. Scalar Stueckelberg fields allow one to have gauge invariance for these vector fields. Both the Abelian and non-Abelian cases are considered. Fully antisymmetric rank-three tensor fields and symmetric rank-two tensor fields are also discussed. PACS No.: 11.15-1
Modelling approach for high flow rate in wastewater treatment operation
Authors: El-Din A G , Smith Daniel W
Published: October 2002

The vast majority of models developed for wastewater treatment and receiving water systems have been of the distributed-parameter and state-space (lumped-parameter) forms. On the other hand, most control system design methods and, for that matter, methods of system identification refer to the black box class of models and in particular the time series models. In the current study two modelling techniques of the black box class of models were used to model the data collected from full-scale treatment operations at the Gold Bar Wastewater Treatment Plant (GBWWTP), the largest plant in the Edmonton area (Alberta, Canada). An artificial neural network was trained to make short-term predictions of the quantity of wastewater entering the plant during storm events using rainfall data collected from eight gauges covering the parts of the city that are serviced by combined sewers. After training, the model was able to generalize very well when tested against an unseen set of data. Transfer function time series models were used to model the quality data collected from a primary sedimentation tank at the plant. The models were able to make hourly predictions of the total suspended solids and chemical oxygen demand in the primary effluent. The presented models have the predictiveness and adaptiveness requirements needed for models that could be utilized as part of a real-time control system. Key words: dynamic modelling, artificial neural networks, transfer-function models, wastewater inflow, primary sedimentation.
Advanced technologies in water and wastewater treatment
Authors: Zhou H , Smith Daniel W
Published: October 2002

The use of conventional water and wastewater treatment processes becomes increasingly challenged with the identification of more and more contaminants, rapid growth of population and industrial activities, and diminishing availability of water resources. Three emerging treatment technologies, including membrane filtration, advanced oxidation processes (AOPs), and UV irradiation, hold great promise to provide alternatives for better protection of public health and the environment and thus are reviewed in this paper. The emphasis was placed on their basic principles, main applications, and new developments. Advantages and disadvantages of these technologies are compared to highlight their current limitations and future research needs. It can be concluded that, along with the growing knowledge and the advances in manufacturing industry, the applications of these technologies will be increased at an unprecedented scale. Key words: water treatment, wastewater treatment, membrane filtration, ozonation, advanced oxidation processes, UV irradiation.
Large-scale brittle and ductile toppling of rock slopes
Authors: Nichol Susan L , Hungr Oldrich , Evans S G
Published: October 2002

Slow, ductile toppling of rock masses commonly creates large-scale mountain slope deformations. In some cases, rock toppling can initiate an extremely rapid catastrophic landslide. This theoretical and field-based study was aimed at distinguishing the two alternative modes of toppling. The idea that certain key parameters of the undeformed rock mass may influence failure behaviour in a quantifiable way was examined through a parametric study of a large rock slope using the universal distinct element code (UDEC). The slope was modelled using variations of rock mass strength, discontinuity orientation and persistence, and toe over-steepening. The results indicated two distinct types of failure behaviour: (i) ductile, self-stabilizing flexural toppling in weak rock with a single dominant joint set; and (ii) brittle, catastrophic block toppling in strong rock containing persistent, down-slope oriented or horizontal cross-joints, which act as surfaces of separation at the base of the toppling blocks. The two mechanisms exhibit very different patterns of prefailure stress. During flexural toppling, the major principal stress is oriented predominantly parallel with the slope surface. In the case of block toppling, it is vertical and a large part of the unstable volume is horizontally destressed. Boundaries between the two types of behaviour have been approximately mapped. Two field case studies were then examined in light of the results. The first case involves a block topple in strong granitic rocks that failed catastrophically and produced a high velocity rock avalanche; and the second case is a large flexural topple in metamorphic rocks, exhibiting slow deformations.Key words: rock toppling, landslide, distinct element model, parametric study, hazard assessment.
Metastable states of silty clays during drying
Authors: Cafaro Francesco
Published: October 2002

An experimental research program has been carried out on the drying behaviour of normally consolidated silty clays with the aim of observing and interpreting state paths followed by soil samples under suction increase at zero external total stress. The behaviour of overconsolidated clays during drying is also discussed for comparison and shows the influence of stress history on the desaturation process. The drying state paths of normally consolidated reconstituted clay samples are plotted together with the corresponding isotropic normal compression lines, assuming equivalence between suction and effective stress for a fully saturated soil. The importance of the stress transmission mechanism in explaining the observed offset between the virgin drying line and the normal compression line is pointed out. Moreover, an energy-based interpretation of this volumetric offset is proposed in terms of fabric metastability.Key words: desaturation, drying, fabric, matric suction, silty clays, volume change.
Cultivation-dependent characterization of bacterial diversity from British Columbia forest soils subjected to disturbance
Authors: Axelrood Paige E , Chow Monica L , Arnold Clarke S , Lu Karen , McDermott Joseph M , Davies Julian
Published: October 2002

Bacteria from forest surface organic matter and mineral soil horizons were cultivated using four methods and characterized by fatty acid methyl ester (FAME) analysis. Soil samples from a British Columbia Ministry of Forests Long-Term Soil Productivity (LTSP) installation were collected during winter and summer from two disturbance treatments (whole-tree harvesting with no soil compaction (plot N) and whole-tree harvesting plus complete surface organic matter removal with heavy soil compaction (plot S)) and from an unlogged reference plot (REF). Seventy-five percent of 1795 bacterial isolates were affiliated with 42 genera representing β- and γ-Proteobacteria, Actinobacteria, the Bacillus/Clostridium group, and the Cytophaga-Flexibacter-Bacteroides group. Approximately half of the culture collection represented genetic diversity confined to four bacterial genera: Pseudomonas, Bacillus, Paenibacillus, and Arthrobacter. A significantly higher proportion of bacterial isolates belonging to Actinobacteria, and the member genus Arthrobacter, were isolated from plot S soil samples compared with soil samples from plots N and REF. Twenty-five percent of bacterial isolates were not conclusively identified to genus with FAME analysis. MIDI Tracker cluster analysis and partial 16S rRNA gene sequence analysis enabled classification of a subset of these isolates.Key words: bacterial diversity, fatty acid methyl ester analysis (FAME), forest soil.
Effects of seasonal and interannual climate variability on net ecosystem productivity of boreal deciduous and conifer forests
Authors: Arain M A , Black T A , Barr A G , Jarvis P G , Massheder J M , Verseghy D L , Nesic Z
Published: October 2002

The response of net ecosystem productivity (NEP) and evaporation in a boreal aspen (Populus tremuloides Michx.) forest and a black spruce (Picea mariana (Mill.) BSP) forest in Canada was compared using a newly developed realistic model of surface-atmosphere exchanges of carbon dioxide (CO2), water vapor, and energy as well as eddy covariance flux measurements made over a 6-year period (1994-1999). The model was developed by incorporating a process-based two-leaf (sunlit and shaded) canopy conductance and photosynthesis submodel in the Canadian Land Surface Scheme (CLASS). A simple submodel of autotrophic and heterotrophic respiration was combined with the photosynthesis model to simulate NEP. The model performed well in simulating half-hourly, daily, and monthly mean CO2exchange and evaporation values in both deciduous and coniferous forests. Modeled and measured results showed a linear relationship between CO2uptake and evaporation, and for each kilogram of water transpired, approximately 3 g of carbon (C) were photosynthesized by both ecosystems. The model results confirmed that the aspen forest was a weak to moderate C sink with considerable interannual variability in C uptake. In the growing season, the C uptake capacity of the aspen forest was over twice that of the black spruce forest. Warm springs enhanced NEP in both forests; however, high mid-summer temperatures appear to have significantly reduced NEP at the black spruce forest as a result of increased respiration. The model suggests that the black spruce forest is a weak C sink in cool years and a weak C source in warm years. These results show that the C balance of these two forests is sensitive to seasonal and interannual climatic variability and stresses the importance of continuous long-term flux measurement to confirm modeling results.
On the validity of the British Columbia Forest Practices Code guidelines for stream culvert discharge design
Authors: Beckers Jos , Alila Younes , Mtiraoui Ahmed
Published: October 2002

In the stream culvert discharge design guidelines of the Forest Practices Code (FPC) of British Columbia (BC), the 100-year instantaneous flood (Q100) is assumed to be three times as large as the mean annual flood (Q2) regardless of basin characteristics and location in the province. A regional linear moment analysis of annual maximum flows is used to demonstrate that this assumption is invalid and that Q100/Q2ratios vary substantially with basin area and climate. For the snowmelt-dominated peak flows in the Columbia and southern Rocky Mountains, Q100/Q2decreases slightly with increasing drainage area, from 2.3 (1 km2) to 1.9 (100 km2). For the flood peaks generated by rainfall and rain on snow in coastal BC, this range is 3.12.6. In the semi-arid Interior Plateau region, variability in Q100/Q2ratios is most dramatic. For a 10-km2basin, the calculated Q100/Q2ratio of 4.9 is 1.6 times the assumed factor of 3, while for a 1-km2basin Q100/Q2is 7.5 or 2.5 times this factor. Underestimating Q100/Q2may lead to underdesign and early failure of road culverts, and therefore, current FPC guidelines for estimating the 100-year instantaneous flood may have serious adverse economic and environmental consequences in small Interior Plateau watersheds.
Predictive mapping of forest composition and structure with direct gradient analysis and nearest- neighbor imputation in coastal Oregon, U.S.A.
Authors: Ohmann Janet L , Gregory Matthew J
Published: October 2002

Spatially explicit information on the species composition and structure of forest vegetation is needed at broad spatial scales for natural resource policy analysis and ecological research. We present a method for predictive vegetation mapping that applies direct gradient analysis and nearest-neighbor imputation to ascribe detailed ground attributes of vegetation to each pixel in a digital landscape map. The gradient nearest neighbor method integrates vegetation measurements from regional grids of field plots, mapped environmental data, and Landsat Thematic Mapper (TM) imagery. In the Oregon coastal province, species gradients were most strongly associated with regional climate and geographic location, whereas variation in forest structure was best explained by Landsat TM variables. At the regional level, mapped predictions represented the range of variability in the sample data, and predicted area by vegetation type closely matched sample-based estimates. At the site level, mapped predictions maintained the covariance structure among multiple response variables. Prediction accuracy for tree species occurrence and several measures of vegetation structure and composition was good to moderate. Vegetation maps produced with the gradient nearest neighbor method are appropriately used for regional-level planning, policy analysis, and research, not to guide local management decisions.
Prediction of organic carbon content in upland forest soils of Quebec, Canada
Authors: Tremblay Sylvie , Ouimet Rock , Houle Daniel
Published: October 2002

Soil organic carbon (C) is an important component of forest carbon pools and should be taken into account in sustainable forest management. However, there is a need to derive indicators for this attribute, as organic C content (Mg·ha1) in forest soils is generally not available in Quebec survey data. Thus, we developed models to predict organic C accumulation in the forest floor and in mineral soils of upland forest soils (i.e., with forest floor thickness [Formula: see text]30 cm) using soil survey data as input variables. The best-fit model for predicting forest floor organic C content consisted of the explanatory variables forest floor thickness, latitude, and longitude. The model R2 was 0.76, and its CV was 28%. The second best-fit model, excluding geographical coordinates, included forest floor thickness and mean growing season precipitation as explanatory variables (R2 = 0.71, CV = 29.5%). The model for predicting mineral soil organic C content was composed of two submodels: (i) organic C concentration of a mineral horizon as a function of its colour and (ii) bulk density of that horizon as a function of its estimated C concentration (obtained from the former model). The R2 of the model for predicting organic C content in mineral soils was 0.57, and its CV was 29%. The models were used to predict organic C contents in 5547 pedons, dispersed throughout the commercial forest of Quebec and for which basic soil profile description data were available. It was then possible to evaluate and compare mean soil C accumulation in different forest stand types and to construct two maps of soil organic C accumulation in upland forest soils of southern Quebec. The results pointed out that forest floor thickness combined with mineral soil horizon colour, texture class, and pH would be useful sustainable forest management indicators of organic C accumulation in upland forest soils.
The effects of silvicultural disturbances on the diversity of seed-producing plants in the boreal mixedwood forest
Authors: Bell F Wayne , Newmaster Steven G
Published: October 2002

The practice of clear-cutting, followed by site preparing with mechanical equipment, planting a single tree species, and applying herbicides, has recently been cited as a procedure that creates monocultures in northern forests. Research on a trembling aspen (Populus tremuloides Michx.) dominated mixedwood provided an opportunity to examine the potential of silvicultural activities to (i) create monocultures, (ii) create opportunities for the establishment of exotic plant species, and (iii) result in the loss of indigenous plant species. Detailed botanical surveys were conducted for up to 5 years post-treatment in four clearcuts that were mechanically site prepared, planted with a single conifer species, and released with either motor-manual, mechanical, or herbicide treatment. Species richness, abundance (foliar cover), diversity indices, and rank abundance diagrams indicate that the treatments had immediate effects, but none created a monoculture during the period of study. We conclude that the use of clear-cutting, mechanical site preparation, planting a single conifer species, followed by release with motor-manual cutting, mechanical cutting, or herbicide spraying, will not create monocultures in the conditions tested. While 37 exotic species were observed, none of them were tree or shrub species. In addition, no net loss of indigenous seed producing plants was detected. Missed strips and patches, which accounted for up to 25% of the sampled area, buffered treatment effects.
Long-term patterns of diameter and basal area growth of old-growth Douglas-fir trees in western Oregon
Authors: Poage Nathan J , Tappeiner, II John C
Published: October 2002

Diameter growth and age data collected from stumps of 505 recently cut old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees at 28 sample locations in western Oregon (U.S.A.) indicated that rapid early and sustained growth of old Douglas-fir trees were extremely important in terms of attaining large diameters at ages 100300 years. The diameters of the trees at ages 100300 years (D100D300) were strongly, positively, and linearly related to their diameters and basal area growth rates at age 50 years. Average periodic basal area increments (PAIBA) of all trees increased for the first 3040 years and then plateaued, remaining relatively high and constant from age 50 to 300 years. Average PAIBA of the largest trees at ages 100300 years were significantly greater by age 20 years than were those of smaller trees at ages 100300 years. The site factors province, site class, slope, aspect, elevation, and establishment year accounted for little of the variation observed in basal area growth at age 50 years and D100D300. The mean age range for old-growth Douglas-fir at the sample locations was wide (174 years). The hypothesis that large-diameter old-growth Douglas-fir developed at low stand densities was supported by these observations.
The thermal regimes of brook trout incubation habitats and evidence of changes during forestry operations
Authors: Curry R Allen , Scruton David A , Clarke Keith D
Published: October 2002

The thermal regimes in streambed substrates used by brook trout, Salvelinus fontinalis Mitchell, for incubation of embryos were examined in reference and treatment (0- and 20-m riparian buffer strips) streams in a clear-cut harvested, northern temperate forest of western Newfoundland. In these streams, incubation habitats (redds) were primarily composed of downwelling surface waters with variable but minor mixing of upwelling groundwater. The resulting incubation temperatures were cold (<1°C) and surface water temperatures were accurate predictors of redd temperatures. Both treatment streams displayed evidence of warming in the fall and spring of the 2 years beginning the year of initial harvesting. The increase was most pronounced in the stream without a riparian buffer strip. Clear-cut harvesting with and without a riparian buffer strip altered the thermal regime of surface water and the hyporheic zone in this northern temperate forest where, in addition to salmonid incubation, many biological processes take place. The potential for impacts on stream ecosystems is estimated to be high for the managed forests of this region. Future studies should strive to enhance our understanding of the hydrological connections between forests and streams on this landscape to determine the full effects of timber harvesting on the hydrology and biology of a watershed and its streams.
Developing a production possibility set of wildlife species persistence and timber harvest value
Authors: Calkin David E , Montgomery Claire A , Schumaker Nathan H , Polasky Stephen , Arthur Jeffrey L , Nalle Darek J
Published: October 2002

An integrated model, combining spatial wildlife population and timber harvest and growth models, was developed to explore tradeoffs between the likelihood of persistence of a wildlife species, the northern flying squirrel (Glaucomys sabrinus), and timber production on a landscape on the west side of the Oregon Cascade Range. A simplified wildlife model was developed from the fully parameterized spatial wildlife model, using a habitat neighborhood-weighting scheme, for use in the optimization. Simulated annealing, a heuristic optimization technique, was used to solve for harvest schedules that maximized the net present value of timber harvest subject to a target value for likelihood of species persistence over a 100-year planning period. By solving this problem for a range of species persistence targets, a production possibility frontier was developed that showed tradeoffs between timber harvest value and likelihood of species persistence on this landscape. Although the results are specific to the wildlife species and the landscape analyzed, the approach is general and provides a structure for future models that will help land managers and forest planners to understand tradeoffs among competing resource uses.
Optimum selection age for wood density in loblolly pine
Authors: Gwaze D P , Harding K J , Purnell R C , Bridgwater F E
Published: October 2002

Genetic and phenotypic parameters for core wood density of Pinus taeda L. were estimated for ages ranging from 5 to 25 years at two sites in southern United States. Heritability estimates on an individual-tree basis for core density were lower than expected (0.200.31). Ageage genetic correlations were higher than phenotypic correlations, particularly those involving young ages. Ageage genetic correlations were high, being greater than 0.75. Ageage genetic correlations had a moderately linear relationship, while ageage phenotypic correlations had a strong linear relationship with natural logarithm of age ratio. Optimum selection age for core density was estimated to be 5 years when calculations were based on both genetic and phenotypic correlations. However, age 5 was the youngest examined in this study and optimum selection age may be younger than 5. Generally, the optimum selection age was robust to changes in breeding phase and assumptions concerning age-related variation in heritability estimates. Early selection for core density would result in a correlated increase in earlywood density but little progress in latewood density or latewood proportion at maturity.