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At least 1,531 records · Page 85Linked to original sources
PubMed1998

Experimental study of seita-fitting.

The purpose of this study was to verify the difference between carrying a load on the sacrum (LOS) and on the lumbar vertebrae (LOL) in oxygen uptake, muscle activities, heart rate, cadence, and subjective response. Nine males (26.7 +/- 3.1 years old), each carrying a 7.5 kg carrier frame and a 40 kg load, walked on a treadmill at a speed of 50 m/min. EMGs were recorded from the trapezius, rectus abdominis, erector spinae, vastus lateralis, rectus femoris, vastus medialis, biceps femoris long head, tibial anterior, soleus, medial head of gastrocnemius, and the lateral head of gastrocnemius. For each subject the integrated EMG (IEMG) was normalized by dividing the IEMG in the LOL and LOS by the IEMG in a no-load condition (NL) for each investigated muscle. The following was significantly higher in LOL than in LOS: oxygen uptake; IEMG of the tibial anterior, soleus, and medial head of gastrocnemius; cadence; and rated perceived exertion. However, IEMG of the erector spinae was significantly lower in LOL than in LOS. These results suggest that seita-fitting in LOS causes a decrease of leg muscle activities, which causes oxygen uptake to decrease beyond the increase of the erector spinae activity.

Adult↗
PubMed2001

Who was... Harry Champion?

From insect collecting on the Surrey heaths, to forest management in Northern India, the rarefied atmosphere of Oxford University and the challenges of international consultancy, Harry Champion's life was rarely dull. As a schoolboy, he had declared his wish to travel widely and discover new species of plant and animal, though he probably never anticipated how far he would travel or how many species he would find.

Animals↗
PubMed2000

[Optimized models of logging-tending system in cutting areas].

The comprehensive advantages of different logging-tending systems in Pinus massoniana forest cutting area were evaluated by set-pair analysis, based on the comparison of their economic and ecological benefits. The results showed that the optimized model for P. massoniana forests in Northern Fujian comprised 40% selective cutting, manual skidding, clear-cutting in ribbon, and natural regeneration with artificial aids, which could also be used in the nearby forests with conditions similar to the experimental area.

China↗
PubMed2000

[Forest ecosystem services and their ecological valuation--a case study of tropical forest in Jianfengling of Hainan Island].

This paper attempts to present forest ecosystem services and their indirect economic value of Jianfengling tropical forest in Hainan Island. The results show that average annual integrated ecosystem service value of Jianfengling tropical forest, which covers 44667.00 hm2, adds up to 664.38 million yuan(Chinese RMB), of which, about 71.64 million yuan is of the output of standing trees and other forest products, about 394.29 million yuan of water-holding, about 2.47 million yuan of soil conservation against erosion, about 13.16 million yuan of carbon fixation for reducing green house effect, about 4.29 million yuan of nutrient retention for N, P, K, Ca and Mg, about 178.53 million yuan of air purification.

Air↗
PubMed2000

[Yi nationality's sacred groves and biodiversity conservation in Chuxiong, Yunnan].

Sacred groves occur in many ethnic minority areas of Yunnan, China, which have ecologically multiplex functions and effects on biodiversity management and conservation at grassroots level. In this paper, an extensive field survey was carried out to evaluate the role of the sacred groves of the Yi nationality in Chuxiong of Yunnan. Three forest communities (sacred grove, common forest and natural reserve) under different management were sampled, and their plant species diversity was compared. The result shows that the total species, endemic species and Shannon-Wiener index in the sacred grove community were respectively 67, 17 and 2.96, higher than those in natural reserve (44.8 and 2.17) and common forest (34.4 and 2.39). The sacred groves of the Yi nationality in Chuxiong of Yunnan play an important role in local biodiversity conservation and management.

Ecosystem↗
PubMed1965

Allergy to lichens. Allergic contact dermatitis from usnic acid produced by lichenized fungi.

Two forest workers affected with allergic contact dermatitis, which occurred only during work in forest areas, showed positive patch test reactions to lichens containing usnic acid and to isolated usnic acid. Lichens are plants composed of fungi living in symbiosis with algae. Usnic acid, one of the lichenic acids which accumulates in lichenized fungi, is a monobasic acid with dibenzofuran structure and antibiotic properties. Dibenzofuran is chemically related to furocoumarans. Lichens are plentiful in temperate zone forests and allergy to usnic acid represents some part of the "cedar-poisoning" problem in British Columbia. Geographical distribution of lichens containing usnic acid suggests that allergy to usnic acid will be found to be more common than presently recognized.

Adult↗
PubMedDate not supplied

Harvesting and climate effects on organic matter characteristics in British Columbia coastal forests.

As part of investigations into the effects of harvesting old-growth forest, we characterized carbon in five organic matter pools in eight forest chronosequences of coastal British Columbia. Each chronosequence comprised stands in four seral stages from regeneration (3-8 yr) to old-growth (>250 yr), with second-growth stands mostly of harvest origin. Stands were located in two biogeoclimatic subzones with contrasting climate (wetter, slightly cooler conditions on the west coast of Vancouver Island than on the east). Carbon concentrations in fine woody debris (FWD), forest floor (LFH), fine roots from LFH, and two water-floatable fractions from 10 to 30 cm mineral soil (MIN-ROOT, 2-8 mm and MIN-FLOAT, <2 mm) showed no significant effects due to climate, seral stage, or site. There were some significant differences in N concentrations, but none related to seral stage. Carbon-13 cross-polarization with magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectra with principal component analysis of relative areas also showed little harvesting effect, but greater variation related to input of coarse woody debris (CWD) vs. roots high in tannin. Overall, there tended to be more spectral features associated with wood and lignin in the west; whereas some MIN-ROOT samples from the drier east side had aromatic intensity attributed to charcoal. The minimal effects of one harvest on organic matter are most likely due to the large legacy effect; however, more intensive management will probably result in less CWD retention, less charcoal input, and less microsite variability in these pools of poorly decomposed organic matter.

Astringents↗
PubMedDate not supplied

Characterization of high-tannin fractions from humus by carbon-13 cross-polarization and magic-angle spinning nuclear magnetic resonance.

Condensed tannins can be found in various parts of many plants. Unlike lignin there has been little study of their fate as they enter the soil organic matter pool and their influence on nutrient cycling, especially through their protein-binding properties. We extracted and characterized tannin-rich fractions from humus collected in 1998 from a black spruce [Picea mariana (Mill.) Britton et al.] forest in Canada where a previous study (1995) showed high levels (3.8% by weight) of condensed tannins. A reference tannin purified from black spruce needles was characterized by solution 13C nuclear magnetic resonance (NMR) as a pure procyanidin with mainly cis stereochemistry and an average chain length of four to five units. The colorimetric proanthocyanidin (PA) assay, standardized against the black spruce tannin, showed that both extracted humus fractions had higher tannin contents than the original humus (2.84% and 11.17% vs. 0.08%), and accounted for 32% of humus tannin content. Consistent with the results from the chemical assay, the aqueous fraction showed higher tannin signals in the 13C cross-polarization and magic-angle spinning (CPMAS) NMR spectrum than the emulsified one. As both tannin-rich humus fractions were depleted in N and high in structures derived from lignin and cutin, they did not have properties consistent with recaldtrant tannin-protein complexes proposed as a mechanism for N sequestration in humus. Further studies are needed to establish if tannin-protein structures in humus can be detected or isolated, or if tannins contribute to forest management problems observed in these ecosystems by binding to and slowing down the activity of soil enzymes.

Astringents↗
PubMed2002

Workshop 6 (synthesis): linking between flood risks and land use changes.

Land use changes, such as deforestation, are increasing the world's vulnerability to flooding. Detailed knowledge of the local situation is essential for risk assessment and design of effective flood prevention measures and governs the infrastructure and engineering measures implemented. However extreme floods in large catchments can overwhelm both natural capacity and constructed flood management measures.

Agriculture↗
PubMed2002

Land-use change and floods: what do we need most, research or management?

Land-cover change (urbanisation, deforestation, and cultivation) results in increased flood frequency and severity. Mechanisms include reduced infiltration capacity, lower soil porosity, loss of vegetation, and forest clearing, meaning lower evapotranspiration. Major research challenges lie in quantification of effects in terms of flood characteristics under various conditions, ascertaining the combined effects of gradual changes over long time periods, and developing model tools suitable for land-use management. Large floods during the 1990s gave a new focus on these problems. Reference is made to the Norwegian HYDRA research programme on human impacts on floods and flood damage. The paper concludes that land-use change effects on floods are most pronounced at small scale and for frequent flood magnitudes. Model simulations of effects of land-use change can now be used to reduce flood risk. Modern flood management strategies have abandoned the position that dams and dikes are the only answers to mitigating flood disasters. Today, the strategic approach is more often: do not keep the water away from the people, keep people away from the water. Flood management strategies should include flood warnings, efficient communication, risk awareness, civil protection and flood preparedness routines, effective land-use policies, flood risk mapping, ... as well as structural measures.

Agriculture↗
PubMed2002

Micropropagation of Prosopis chilensis (Mol.) Stuntz from young and mature plants.

Prosopis chilensis (Mol.) Stuntz (Algarrobo de Chile) is an important native tree species that can be grown in arid and semiarid regions for wood and forage production and environmental protection. Developing a simple and reliable in vitro protocol for cloning it would enable to improve it genetically. Explants of P. chilensis were taken from 4 months-old plants grown in the greenhouse or from adult trees grown in a natural environment. Nodal segments 1-2 cm long containing an axillary bud were selected from elongating shoots. These cuttings were aseptically cultured on two agar-solid basal media, MS or BTMm, and treated with 0.05 mg L-1 BA and 3 mg L-1 of either IAA, IBA or NAA. Sucrose (3% w/v) was used as carbon source. The percentage of sprouted cuttings and whole plant regeneration as well as its shoot and root length were recorded. Number, length and dry weight of shoots and roots were also measured. Rooting was successful with cuttings taken from young or adult plants, but explants from young plants showed a better response. Culturing in BTMm resulted in significantly greater shoot and root biomass than culturing in MS. Moreover, this response was higher in young explants when IBA was used as growth regulator. This paper reports a simple and effective method to micropropagate P. chilensis from young and adult plants.

Culture Media↗
PubMed2002

Phosphorus reductions following riparian restoration in two agricultural watersheds in Vermont, USA.

Achievement of management goals for Lake Champlain (Vermont/New York, USA and Quebec, Canada) will require significant reductions of phosphorus (P) loads from agriculture, the dominant diffuse source in the basin. Cost-effective P reduction strategies must be based on reliable treatment techniques beyond basic erosion control and animal waste storage practices. The Lake Champlain Basin Agricultural Watersheds National Monitoring Program (NMP) Project evaluates the effectiveness of low-cost livestock exclusion, streambank protection, and riparian restoration practices in reducing concentrations and loads of diffuse-source pollutants from grazing land at the watershed level. Treatment and control watersheds in northwestern Vermont have been monitored since 1994 according to a paired-watershed design. Monitoring includes continuous stream discharge recording, flow-proportional sampling for total P and other pollutants, and documentation of land use and agricultural management activities. Strong statistical calibration between the control and treatment watersheds has been achieved. Landowner participation in the land treatment program was entirely voluntary and all treatments were 100% cost-shared by the project and cooperators. Installation of riparian fencing, alternative water supplies, protected stream crossings, and streambank bioengineering was completed in 1997 at a cost of less than US$40,000. The paired-watershed design was effective in controlling for the influence of extreme variations in precipitation and streamflow over six years of monitoring. Two years of post-treatment data have documented significant reductions in P concentrations and loads from both treated watersheds. Reductions of approximately 20% in mean total P concentration and approximately 20-50% in mean total P load have been observed, with greater reductions occurring in the watershed receiving more extensive treatment. The effectiveness of riparian zone restoration in P reduction tended to be lower during periods of very high runoff, especially outside the growing season.

Agriculture↗
PubMed2002

Hydrogeological constraints on riparian buffers for reduction of diffuse pollution: examples from the Bear Creek watershed in Iowa, USA.

Riparian Management Systems (RiMS) have been proposed to minimize the impacts of agricultural production and improve water quality in Iowa in the Midwestern USA. As part of RiMS, multispecies riparian buffers have been shown to decrease nutrient, pesticide, and sediment concentrations in runoff from adjacent crop fields. However, their effect on nutrients and pesticides moving in groundwater beneath buffers has been discussed only in limited and idealized hydrogeologic settings. Studies in the Bear Creek watershed of central Iowa show the variability inherent in hydrogeologic systems at the watershed scale, some of which may be favorable or unfavorable to future implementation of buffers. Buffers may be optimized by choosing hydrogeologic systems where a shallow groundwater flow system channels water directly through the riparian buffer at velocities that allow for processes such as denitrification to occur.

Biodegradation, Environmental↗
PubMed2002

When the bough breaks: a 10-year review of logging injuries treated at a rural trauma center in Pennsylvania.

The purpose of this study was to describe logging-related injuries at a Pennsylvania trauma center and evaluate the impact of helmets and profession. Charts of patients from 1990 through 1999 admitted after logging accidents were retrospectively reviewed. Most injuries were to the head (71 in 28 patients). Injury Severity Score was greater for helmeted loggers (21.0 vs 11.8; P = 0.02) but did not differ by profession. Mean hospital stay was not significantly different for helmeted loggers (9.6 vs 5.4 days, P = 0.499). Mean length of stay was 8.2 days and 3.5 days for professionals and nonprofessionals, respectively (P = 0.01). Professional loggers tended to remain hospitalized longer. Helmet use does not appear to affect injury severity; however, this could be a result of the catastrophic nature of many logging accidents. Most loggers in this study were not wearing helmets, which suggests that improved educational efforts are needed to improve safety in this dangerous occupation.

Accident Prevention↗
PubMed2002

[Concentration of sVAP in serum of patients with different forms of Lyme borreliosis].

OBJECTIVES: The aim of our work was to assess the serum concentration of soluble VAP-1 (sVAP-1) in patients with arthral type of borreliosis and erythema migrans. METHODS: We included in our study 30 patients in the age of 17-53 years who were treated for erythema migrans and 30 patients in the age of 25-63 years who were diagnosed with arthral type of borreliosis. The control group consisted of 30 healthy blood donors. The diagnosis of borreliosis was made on the basis of anamnesis, physical examination and additional tests, one of which proved the existence of IgM and IgG antibodies against Borrelia burgdorferi antigen present in the serum of patients. All samples for investigations were taken in a single collection manner. The serum concentration of sVAP-1 protein was assessed with ELISA method. All data were analysed statistically. We assumed 5% risk of conclusion error. CONCLUSIONS: 1. We did not observe an increase in serum sVAP-1 concentration in patients with erythema migrans compared to the control group. All observed differences in the serum level of this protein seemed to be random ones. 2. We showed a statistically important increase in soluble sVAP-1 serum concentration in patients with arthral type of borreliosis compared to the control group.

Adult↗