bluuebunny/crossref_metadata_2025 huggingface dataset:
Relationships between Solutes, Nutrients, and the Biofilm in Sediments of Floodplain Karstic and Alluvial Springs
Authors: Chafiq Mohamed , Gibert Janine
Published: February 2007

Two pairs of springs were surveyed in the floodplain of the Upper Rhône River. Each pair included a karstic (upstream) and an alluvial (downstream) spring in the same catchment. Various physical, chemical, and biological factors were measured in the water and the sediment. The study showed karstic and alluvial spring typology. In each pair, the karstic springs were characterized by higher alkalinity, whereas alluvial springs were fed both by karstic groundwater and Rhône River water with higher sulphate content.

Organic matter dynamics and retention processes were different in each spring. The distribution and abundance of fine sediment played a prominent role in the storage of particulate organic carbon and the development of microbial biomass and activity. The hydrological cycle governed organic and inorganic nutrient fluxes, and was, with temperature, the main factor influencing microbial and macroinvertebrate dynamics. The high amount of organic matter in one alluvial spring was correlated with high microbial biomass and activity.
Substantial Increase of Chironomus Abundance Obtained in Field Experiment
Authors: Kajak Zdzisław , Dusoge Krzysztof
Published: February 2007

Mud (with or without Chironomus) taken from the bottom of a shallow (6 m) eutrophic reservoir, was maintained (about 3 weeks) in trays supported 30 cm and 70 cm above the bottom. At the end of the experiment it contained 7‐9 times more Chironomus plumosus individuals than did the mud at the bottom. Numbers of young (≤12 mm) larvae were up to 18 times higher, and youngest (≤6 mm) larvae (absent in the bottom at the end of the experiment) were abundant. Such patterns were more evident at the higher (70 cm) than the lower (30 cm) level. Numbers of the oldest (≥18 mm) larvae at the higher level were only 6 times higher (whilst more than 8 times at the lower level) than at the bottom, probably due to quicker development and emergence in higher trays. So the production of the population increased with the increasing distance from the bottom. In the tray at the bottom (which could protrude 1–2 cm above it) numbers were twice those outside it, and the youngest larvae occurred.

There was a slight current at the research site. Nevertheless, short time oxygen deficits occurred periodically, and were probably the main cause of considerable reductions in Chironomus numbers at the bottom during the experiment.
Strategies of nitrogen cycling of Phragmites australis at two sites differing in nutrient availability
Authors: Kühl Harald , Woitke Peter , Kohl Johannes‐Günter
Published: February 2007

Below‐ground biomass and nitrogen content were determined at two genetically homogeneous Phragmites stands differing in morphology, in productivity, and in nutrient supply. Comparable ratios between above‐ground standing crop and rhizome biomass were found at both sites, whereas the root biomass/above standing crop ratio was significantly higher at the nutrient poor site. Investigations on the dynamics of nitrogen content revealed distinct differences in nitrogen translocation to the rhizomes between the investigated clones indicating two ecophysiological strategies in storage behaviour. These two strategies could be attached to the “assimilation type” and to the “translocation type”, respectively. A modified definition of both types is presented.
Zooplankton and bacteria contribution to phosphorus and nitrogen internal cycling in a tropical and eutrophic reservoir: Pampulha Lake, Brazil
Authors: Pinto‐Coelho Ricardo Motta , de Moura Raquel Teixera , Moreira Andrea
Published: February 2007

Nutrient regeneration and respiration rates of natural zooplankton from a tropical reservoir were experimentally measured. Excretion rates of ammonia (Ea), orthophosphate (Ep) and community respiration rates (R) were estimated considering the variations in the concentrations of ammonia, orthophosphate and dissolved oxygen between control and experimental units. The ranges obtained for these rates from the 2 h assays were Ea = 1.95–4.95 μg N‐NH4 · mg · DW−1 · h−1; Ep = 0.12–0.76 μg P‐PO4 mg DW−1 · h−1. Respiratory rates were quite constant (R = 0.01–0.02 mg O2 · mg DW−1 · h−1). The uptake of nutrients due to bacteria can affect the experimental determination of excretion rates of zooplankton. Orthophosphate release increased from 0.28 to 0.82 μg P‐PO4 · mg DW−1 · h−1 when bacterial activity was depleted by antibiotic addition in experimental vessels (Exp IV). This demonstrates that free living bacteria are able to consume promptly most phosphorus excreted by zooplankton. Ammonia excretion rates were lower in experimental units containing antibiotics. Lower excretion rates were also obtained with longer exposure times and higher biomass levels in the experimental units. Finally, this study also showed that zooplankton excretion can affect significantly turn over rates of total phosphorus in Pampulha Reservoir. In some periods, specially during the dry season when zooplankton biomass was very high, phosphorus release by zooplankton, during one single day, can be as high as 40% of the total phosphorus content in lake water (Turn over time = 2.5 days).
Extracellular, low‐affinity β‐N‐acetylglucosaminidases linked to the dynamics of diatoms and crustaceans in freshwater systems of different trophic degree
Authors: Vrba Jaroslav , Kofroňová‐Bobková Jitka , Pernthaler Jakob , Simek Karel , Macek Miroslav , Psenner Roland
Published: February 2007

Extracellular hydrolysis of 4‐methylumbelliferyl β‐N‐acetylglucosaminide was measured in the oligomesotrophic Piburger See and the eutrophic Římov reservoir during spring and summer phytoplankton blooms, respectively. Total enzymatic activity (TEA) ranged between 0.2 and 19.1 nmol 1−1 h−1 in the reservoir and between 0.8 and 12.4 nmol 1−1 h−1 in the lake. High‐affinity (Km < 1 μmol 1−1) and lowaffinity (Km > 100 μmol 1−1) enzymes were kinetically identifiable in most samples from both localities. The low‐affinity enzyme activity (LEA) usually accounted for >60% (mean: 80%) of TEA. LEA and diatom biomass significantly correlated over time in the reservoir epilimnion (rs = 0.578) and in the lake metalimnion (rs = 0.862). As diatoms possess chitin and take up its monomer, N‐acetylglucosamine, two explanations of the observed relationships are suggested: extracellular β‐N‐acetylglucosaminidase activity partly originates either from ectoenzymes of chitinolytic bacteria attached to diatom cells or from ectoenzymes of diatoms, enabling them to take up N‐acetylglucosamine from ambient amino sugars instead of synthesizing it de novo. A significant positive correlation of LEA with crustacean abundance was found in the lake epilimnion (rs = 0.850), apparently reflecting the growing spring populations of frequently moulting juvenile crustaceans. A possible contribution of chitinolytic bacteria, accompanying the crustacean populations, to LEA is discussed.
Organic carbon dynamics in shelf edge sediments off the hebrides: A seasonal perspective
Authors: Mitchell Lynda , Harvey S. Martyn , Gage John D. , Fallick Anthony E.
Published: February 2007

A benthic transect across the Hebridean Shelf Edge was sampled 9 times during 1995–96. Sediment samples from within the surface mixed layer were analysed for organic and inorganic carbon content, porosity, grain size and stable carbon isotope ratio. The organic carbon content is always <1% dry weight. Inorganic carbon content is 17–65% CaCO3. There is no significant seasonal variation in organic or inorganic carbon contents despite changing productivity in the water column. However, there is an inverse relationship between organic carbon content and median grain size. The isotopic composition shows strong seasonal variation which reflects the increase in phytoplankton detritus at the sediment‐water interface during spring/summer. The results suggest a small but rapid burial flux. However, the study area is not a significant depocentre for organic carbon.
Primary production of phytoplankton in Lake Valencia (Venezuela)
Authors: Infante Aida G.
Published: February 2007

Lake Valencia is heavily polluted by waste water of domestic, agricultural and industrial origin. The high organic load may have produced important changes in the limnological properties. Cyanobacteria dominated in numbers and biomass (over 90% throughout the year). Chlorophyll‐a content averaged 37.7 + 15 μg · 1−1. Maximum concentrations of 50–80 μg · 1−1 were found near the inflows affected by organically polluted affluents. There has been a 50% reduction in the euphotic zone in only 13 years. The maximum rate of gross photosynthesis per hour at light saturation was determined within the uppermost 1‐meter layer. The highest value was 16,290 mg O2 · m−3 · h−1. Lake Valencia is among the most productive lakes in the world, with areal net photosynthesis averaging 7.5 g C · m−2 · d−1.
Natural aquatic plant colonisation in a newly constructed Irish Canal
Authors: Caffrey Joseph , Monahan Catherine
Published: February 2007

In January 1989 a major breach in a section of the Grand Canal occurred. As a consequence, a 2.5 km long section required reconstruction. The channel was built up using peat material, lined with an impermeable membrane and overlayed with Puddle Clay. The section was rewatered in March 1990. For the next 30 months the course of natural aquatic plant colonisation was monitored. The first coloniser was the charophyte Tolypella glomerata, which appeared in September 1990. This occurred with low abundance until April 1991, when it disappeared. Between September 1991 and April 1992 charophytes, mainly T. glomerata and Chara vulgaris, proliferated. Their abundance diminished significantly during the summer of 1992. It was not until August 1991, 18 months after rewatering, that the first naturally colonising phanerogams were recorded. Principal among these was Myriophyllum verticillatum. In September of that year an aggressive coloniser in Irish canal and river habitats, Potamogeton pectinatus, was first observed. This became a permanent constituent of the flora and ultimately dominated the vegetation at the site. In total, 28 plant species were recorded from the newly constructed section. Nine of these species were either purposely or accidentally introduced during bankside stabilisation operations when live roots and rhizomes were planted along the exposed canal margins. By the end of the study period an abundant and diverse macroinvertebrate community had colonised the vegetation.
Phytoplankton community structure of a deep subalpine Italian Lake (Lake Orta, N. Italy) four years after the recovery from acidification by liming
Authors: Morabito Giuseppe , Curradi Michela
Published: February 2007

The phytoplankton succession in Lake Orta, heavy metals and ammonium polluted for decades and subjected to liming intervention in 1989–90, was studied during 1994. The existence of three main succession stages, with different structures of the community emerged. Chlorophyta are the most important taxonomic group in every season. The spring community was dominated by chlorophytes, Dinobryon sertularia and Kephyrion sp., the summer by Synedra sp. and Westella botryoides, the autumn by Rhizosolenia eriensis and W. botryoides, the winter by Synedra sp., R. eriensis and Synechococcus sp. The abundance of Chlorophyta, less important in other deep subalpine lakes, and the dominance of taxa able to thrive in polluted environments, could be related to the presence of trace metals in the sediments.
Neoperla (Plecoptera, Perlidae) Emerging from a Mountain Stream in Central Africa
Authors: Zwick Peter
Published: February 2007

Study of numerous adults was done for 5 species of Neoperla taken in an emergence trap on the stream Kalengo, Republic of Zaire, over 16 months (table 1). Taxonomic characters are evalutaed considering individual variation and variation between disjunct populations. The assumption by previous authors of only 1 variable species of Neoperla in Africa is refuted. Some bionomic data for the 2 common species in the material are presented. Biomass (dry weight) is 462.4 mg/m2/yr or 12% of total biomass of emerging insects (BÖTTGER 1975). Close agreement with figures reported for European streams (ILLIES 1971) may be accidental as biocoenotic structures are very different.
Abundance and Distribution of the Macrobenthic Infauna of the Gulf of Arauco, Chile
Authors: Carrasco Franklin D. , Gallardo Victor A.
Published: February 2007

The macrobenthic infauna of the Gulf of Arauco (Central Chile), was quantitatively sampled in April 1979. A total of 81 species were identified. The infauna was greatly dominated by polychaetes. The polychaete Paraprionospio pinnata and the amphipod Ampelisca araucana accounted for ca. 45 per cent of the total infauna in terms of numbers. Numerical classification produced four site‐groups and four species‐groups, mostly reflecting differences in character and depth of sediment. Several community characteristics differed for these assemblages. Biomass also was dominated by polychaetes, with Pectinaria chilensis, P. pinnata, Diopatra chiliensis and Glycera americana making up 45 per cent of the total. The high numbers of the fauna (mean = 15,021 ind m−2) and especially the high biomass figures (mean = 21.04 g AFDW m−2) reported are consistent with the high productivity of the area, subject to coastal upwelling processes.
Spatial Dynamics of Mesocyclops edax (S. A. FORBES), Tropocyclops prasinus mexicanus KIEFER, Diaptomus pallidus HERRICK, Ceriodaphnia lacustris (BIRGE), Bosmina longirostris (O. F. MÜLLER), Daphnia parvula (FORDYCE) and Nauplii in a Northeastern Ohio Pond
Authors: Teraguchi Mitsuo , Stucke Dennis E. , Noga Michael M.
Published: February 2007

A hypothesis on spatial dynamics of pelagic crustacean plankters was tested with the copepods and cladocerans of Squire Pond, Ohio. There was an agreement between the expected and the observed pattern of overall horizontal distribution in most instances for Mesocyclops edax, Tropocyclops prasinus mexicanus, Ceriodaphnia lacustris, Bosmina longirostris and nauplii, but only in a few instances for Diaptomus pallidus and Daphnia parvula. Windward accumulation was common for the first 4 species and near uniform distribution was frequent for the nauplii. Vertical‐distribution trend along transect for all species rarely corresponded with the expectation. Alternation of modal depth along transect was one of the most frequently observed trends. Ways to test the hypothesis in the future are discussed.
Stabilization of native penicillin G acylase by ionic liquids
Authors: de los Ríos Antonia P. , Hernández‐Fernández Francisco J. , Rubio Manuel , Gómez Demetrio , Víllora Gloria
Published: January 2007

Five different ionic liquids, based on dialkylimidazolium cations associated with perfluorinated and bis{(trifluoromethyl)sulfonyl}imide anions, were used to investigate the scope and limitations of these new solvents as media for penicillin G acylase‐catalyzed reactions. Deactivation of the native enzyme in ionic liquids (ILs) and in organic solvents (toluene, dichloromethane and 2‐propanol) at low water content and 40 °C was investigated using the hydrolysis of penicillin G as activity test. Native penicillin G acylase shows greater stability in IL media than in organic solvents. For example, a half‐life time of 23 h was obtained in 1‐ethyl‐3‐methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [emim+][Tf2N−], which was about 2000‐fold higher than that in 2‐propanol. An enhancement of the PGA stability was observed by the presence of substrate in ionic liquids based on tetrafluoroborate and hexafluorophosphate anions, achieving the highest increase of the half‐life time in 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim+][PF6−]), which was about 9‐fold higher than the half‐life time in the absence of substrate. Copyright © 2007 Society of Chemical Industry
Enhancing the potency of HBV DNA vaccines using fusion genes of HBV‐specific antigens and the N‐terminal fragment of gp96
Authors: Yan Jiabin , Liu Xuqing , Wang Yao , Jiang Xiaomo , Liu Huayu , Wang Mingying , Zhu Xiaodong , Wu Min , Tien Po
Published: January 2007

Background

Many clinical trials show that DNA vaccine potency needs to be greatly enhanced. We have reported that the N‐terminal fragment of glycoprotein 96 (gp96) is able to produce an adjuvant effect for production of cytotoxic T‐lymphocytes (CTLs) with hepatitis B virus (HBV)‐specific peptides. Here, we report a new strategy for HBV DNA vaccine design using a partial gp96 sequence.

Materials and methods

We linked the N‐terminal 1‐355aa (N355) of gp96 to HBV genes encoding for structural proteins, the major S and middle S2S envelope proteins and the truncated core HBcAg (1‐149aa). ELISPOT, tetramer staining and intracellular IFN‐γ assay were performed to analyze the induced cellular immune responses of our DNA constructs in BALB/c mice and HLA‐A2 transgenic mice. The relative humoral immune responses were analyzed in different IgG isotypes.

Results

The fusion genes induced 2‐ to 6‐fold higher HBV‐specific CD8+ T cells as compared to the antigens alone. There was an approximate 10‐fold decrease in the humoral immune responses with fusion genes based on HBV envelope proteins. Interestingly, the decreased humoral immune responses were not observed when antigens and plasmid encoding N355 were co‐delivered. However, an approximate 20‐fold higher antibody level was induced when linking N355 to a truncated HBcAg. Immunization by intramuscular injection resulted in predominantly IgG2a antibodies, which indicated that these vaccines preferentially prime Th1 responses.

Conclusions

We constructed highly immunogenic fusions by linking the N‐terminal fragment of gp96 to HBV antigens. Our results imply that the N‐terminal fragment of gp96 may be used as a molecular adjuvant to enhance the potency of DNA vaccines. Copyright © 2007 John Wiley & Sons, Ltd.
Development of a second‐generation oncolytic Herpes simplex virus expressing TNFα for cancer therapy
Authors: Han Z. Q. , Assenberg M. , Liu B. L. , Wang Y. B. , Simpson G. , Thomas S. , Coffin R. S.
Published: January 2007

Background

Tumour necrosis factor alpha (TNFα) therapy is a promising anti‐cancer treatment when combined with radiotherapy due to its potent radio sensitising effects, but systemic toxicity has limited its clinical use. Previously, non‐replicative adenovirus vectors have been used to deliver TNFα directly to the tumour, including under the control of a radiation sensitive promoter. Here, we have used an ICP34.5 deleted, oncolytic herpes simplex virus (HSV) for delivery to increase expression levels and spread through the tumour, and the use of the US11 true late HSV promoter to limit expression to where the virus replicates, i.e. selectively in tumour tissue.

Methods

TNFα expression under the CMV or US11 promoter was compared on cell lines CT26, BHK and Fadu. To further compare the activities of the promoters, expression of human TNFα was analysed in the presence and absence of acyclovir‐ an inhibitor of viral DNA replication and on HSV/ICP34.5‐ non‐permissive cell line 3T6. The in vivo efficacy and toxicity of TNFα viruses were compared using A20 double flank tumour model in Balb/C mice and Fadu tumour model in nude mice.

Results

The results demonstrated that the US11 promoter significantly reduced and delayed TNFα expression as compared to use of the CMV promoter, especially in non‐permissive cells or in the presence of acyclovir. Despite the reduced and more selective expression levels, US11 driven TNFα showed improved anti‐tumour effects compared to CMV driven TNFα, and without the toxic side effects.

Conclusions

This approach is therefore beneficial in increasing localised TNFα expression as compared to the use of non‐replicative approaches, and combines the effects of TNFα with oncolytic virus replication which is expected to further enhance the efficacy of radiotherapy in a combined treatment approach. Copyright © 2007 John Wiley & Sons, Ltd.
Morphology, constraints, and scaling of frontal sinuses in the hartebeest, Alcelaphus buselaphus (Mammalia: Artiodactyla, Bovidae)
Authors: Farke Andrew A.
Published: February 2007

The frontal sinuses of bovid mammals display a great deal of diversity, which has been attributed to both phylogenetic and functional influences. In‐depth study of the hartebeest (Alcelaphus buselaphus), a large African antelope, reveals a number of previously undescribed details of frontal sinus morphology. In A. buselaphus, the frontal sinuses conform closely to the shape of the frontal bone, filling nearly the entire element. However, the horncores are never extensively pneumatized, contrasting with the condition seen in many other bovids. This evidence is inconsistent with the hypothesis that sinuses are opportunistic pneumatizing agents, suggesting that phylogenetic factors also play a role in determining sinus size. Both cranial sutures and neurovasculature appear to constrain the growth of sinuses in part. In turn, the sinus also affects the growth of the parietal; apparently this element is not truly pneumatized by the sinus in most cases, but the bone's shape changes under the influence of the sinus. Furthermore, the sinuses present relatively few struts when compared with the sinuses of some other bovids, such as Ovis. By adapting methods previously developed for measuring structural parameters of trabecular bone, it is possible to quantify certain aspects of sinus morphology. These include the number of bony struts within the sinus, the spacing of these struts, and the size of individual cavities within the sinus. Some differences in the number of struts are evident between subspecies. Similarly, significant differences occur in the relative number of struts between male and female A. buselaphus, which may be related to behavior. The volume of the sinus is strongly correlated with the size of the frontal, but less so with overall cranial size. This finding illustrates the importance of choosing variables carefully when comparing sinus sizes and growth between species. J. Morphol., 2007. © 2007 Wiley‐Liss, Inc.
A novel capillary microextraction on ordered mesoporous titania coating combined with electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of V, Cr and Cu in environmental and biological samples
Authors: Wu Yiwei , Hu Bin , Hu Wenling , Jiang Zucheng , Li Boyangzi
Published: January 2007

In this work, an ordered mesoporous titania film was introduced to coat a capillary by means of sol–gel technique. Sol–gel titania coating was developed for the preconcentration/separation of trace V, Cr and Cu by capillary microextraction (CME), and the adsorbed analytes were eluted for electrothermal vaporization inductively coupled plasma mass spectrometry (ETV‐ICP‐MS) detection. By immobilizing sol–gel titania on the inner surface of a fused‐silica microextraction capillary, the sol–gel titania coating was prepared easily. Its adsorption properties, stability and the factors affecting the adsorption behaviors of V, Cr and Cu were investigated in detail. At pH range of 7 to 9, the titania‐coated capillary (50 cm × 0.25 mm) is selective towards V, Cr and Cu, and the target analytes could be desorbed quantitatively with 50 µl of 1.0 mol l−1 HNO3 at the rate of 0.05 ml min−1. With a consumption of 2 ml sample solution, an enrichment factor of 33.3, and a detection limit (3 s) of 1.1 pg ml−1 (10.5 fg) for V; 3.3 pg ml−1 (33.0 fg) for Cr and 6.3 pg ml−1 (63.1 fg) for Cu respectively were obtained. The precisions Relative Standard Deviations (RSDs) for nine replicate measurements of 1 ng ml−1 V, Cr and Cu were 3.4, 5.1 and 6.4%, respectively. The proposed method has been applied to the determination of V, Cr and Cu in human urine and lake water, and the recoveries for these elements were 89.2∼105%. The developed method was also applied to the determination of the target elements in NIES No. 10‐a (rice flour‐unpolished) and NIES No. 9 (sargasso) certified reference materials, and the results found are in good agreement with the certified values. Copyright © 2007 John Wiley & Sons, Ltd.
Astrocytic hypertrophy in dysmyelination influences the diffusion anisotropy of white matter
Authors: Harsan Laura A. , Poulet Patrick , Guignard Blandine , Parizel Nathalie , Skoff Robert P. , Ghandour M. Said
Published: February 2007

The effect of a proteolipid protein (PLP) mutation on the developing white matter anisotropy was examined by diffusion tensor magnetic resonance imaging (DT‐MRI) in a noninvasive study of a mouse model of Pelizaeus‐Merzbacher disease (PMD). The jimpy PLP mutation in mice produces an irreversible dysmyelination in jimpy males, whereas heterozygous females exhibit a transient hypomyelination, as assessed by a longitudinal study of the same mice during development. Modifications of the different individual DT‐MRI parameters were highlighted by specific changes in tissue structures caused by the mutation that includes the hypomyelination, axonal abnormalities, and recovery. Astrocytic hypertrophy is a striking cellular event in dysmyelinated jimpy brain, where most axons or bundles of fibers are entirely wrapped by astrocyte cytoplasmic processes, so its influences on DT‐MRI parameters in dysmyelination were examined for the first time. DT‐MRI data of the jimpy brain were compared with those obtained from dysmyelination of (oligo‐TTK) transgenic mice, induced by oligodendrocyte killing, which have a mild astrocyte hypertrophy (Jalabi et al., 2005), and from recovering jimpy females, which have reduced astrocyte hypertrophy. The unique morphological feature of astrocytes in jimpy males coupled with an increase in the water channel protein aquaporin 4 (AQP4) was found to facilitate the directional water diffusion in the white matter. In addition to the major changes of DT‐MRI parameters in the two dysmyelinated mice caused by the myelin loss and axonal modifications, the amplified magnitude of radial and axial diffusions in jimpy males was attributed principally to the strongly pronounced astrocyte hypertrophy. © 2007 Wiley‐Liss, Inc.
Effects of hyperbaric oxygen treatment on tendon graft and tendon‐bone integration in bone tunnel: Biochemical and histological analysis in rabbits
Authors: Yeh Wen‐Ling , Lin Song‐Shu , Yuan Li‐Jen , Lee Kam‐Fai , Lee M.Y. , Ueng Steve W.N.
Published: February 2007

Despite moderate success in clinical applications, outcome of tendon grafts employed for anterior cruciate ligament (ACL) reconstruction remains unsatisfactory. This study investigated the effects of hyperbaric oxygen (HBO) on neovascularization at the tendon‐bone junction, collagen fibers of the tendon graft, and the tendon graft‐bony interface incorporated into the osseous tunnel in rabbits. Forty rabbits were assigned to two groups. The HBO group was exposed to 100% oxygen at 2.5 atmospheres pressure for 2 h daily, 5 consecutive days in a week. The control group was maintained in cages exposed to normal air. Histological studies of 12 rabbits were performed postoperatively at 6, 12, and 18 weeks. Biomechanical studies of 24 rabbits were conducted postoperatively at 12 and 18 weeks. Electron microscopy (EM) analyses of four rabbits were performed postoperatively at 18 weeks. Experimental results demonstrated that a higher number of Sharpey's fibers bridged the newly formed fibrocartilage and graft in the HBO group than in the control group. In addition, HBO treatment increased neovascularization and enhanced the incorporation of the progressive interface between tendon graft and bone. Biomechanical analysis showed that the HBO group achieved higher maximal pullout strength than the control group. Examination by EM showed that HBO treatment resulted in regenerated collagen fibers with increased compaction and regularity. Based on experimental results, HBO treatment is a treatment modality that potentially improves outcome following ACL reconstruction. © 2007 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25:636–645, 2007
Land degradation, soil conservation and the sediment load of the Yellow River, China: Review and assessment
Authors: Douglas Ian
Published: February 2007

Ninety per cent of the sediment load of the Yellow River, the world's muddiest river, comes from the loess plateau region in the middle course of the river. Control of this sediment supply is essential to avoid the danger of flooding in the lower reaches on the South China Plain. Since 1971, sediment loads entering the lower reaches have decreased, by 20 per cent as a result of lower precipitation, and by 27 per cent through soil conservation works and reservoir construction. Reductions in erosion can be obtained by restraining the formation of overland flow through promotion of an effective vegetation cover and elimination of the soil surface cover to encourage infiltration. Reservoir operation is a key to control of sediment movement through tributaries and along the main river. Water demands often conflict with sediment control, and, as a consequence, reservoir operation systems have changed several times in the past decade. The possibility of a further reduction in the sediment load of the Yellow River exists, but much depends on how rapidly control of grazing and deforestation leads to the establishment of plant cover on the loess plateau.
Application of a low‐cost database to soil erosion and soil conservation studies in the Awash Basin, Ethiopia
Authors: Griffiths J. S. , Richards K. S.
Published: February 2007

In large‐scale land resource planning exercises, Geographical Information Systems (GIS) form a valuable means of storing, retrieving, displaying, and analysing spatially‐referenced data, as well as enabling the simulation of the consequences of various alternative development options. However, at this scale only generalized policies for the allocation of finance can be made, and the implementation of those policies will invariably require detailed evaluation at the local level. This suggests that expenditure on the central planning process itself should be limited, with funds reserved for later site studies. The form of GIS adopted centrally should also lend itself to easy use and interpretation by policymakers and planners. These requirements suggest that GIS development using proprietary off‐the‐shelf database management software may be preferable to high‐technology GIS software. This paper outlines the development of such a GIS, based on dBase‐III‐plus and its internal programming language, in the analysis of problems of soil erosion and soil conservation in the large (110,000 km2) drainage basin of the Awash River in Ethiopia. The methodology employed involves the FAO modification of the Universal Soil Loss Equation, which clearly lacks a secure process basis, but is appropriate for the scale of planning involved and the quality of calibration data available. The GIS is used to map patterns of soil erosion, to identify target areas for conservation on the basis of criteria of sensitivity to land use change, and to assess the costs and benefits of conservation work in those areas. It is suggested that the simple form of GIS involved in this study has much to offer environmental managers in developing countries in the rapid development of plans for soil conservation.
Rehabilitation of alkaline wasteland on the gangetic alluvial plains of Uttar Pradesh, India, through afforestation
Authors: Singh Bajrang
Published: February 2007

A few species of fuelwood trees were established on highly alkaline wasteland at Aligarh (27°5′ N., 78°4′ E.) in a tropical environment. Of these Prosopis juliflora produced maximum biomass (12.05 t ha−1) and had an energy content of 242.11 GJ ha−1 after 3.5 years growth period. The survival percentage of Terminalia arjuna was highest of those the species tried, but their growth and biomass production were inferior to that of Prosopis juliflora and Acacia nilotica. Some of the fuelwood tree plantations were raised without adding any soil amendment but suffered heavy mortality and could not produce any significant quantity of biomass. In another experiment Leucaena leucocephala was identified as a most promising species for afforestation on substandard soils; also it was found that a relatively high population density (of about 7,500 plants per hectare) is required to rehabilitate such land. Of the soil amendments tried, gypsum with farmyard manure and sand in equal proportion gave the better response (gypsum alone was also tried). Two species of shrubs: Sesbania sesban and Tamarix dioca have shown good adaptability in difficult habitats. After five years of afforestation the soil properties of the sites improved significantly, showing marked reduction in pH, EC and ESP values and an increase in organic carbon content.
Soil alkalinization and salinization in the djajerud Basin, Iran
Authors: Valles V. , Gholami M. , Lambert R.
Published: February 2007

The Djajerud Basin is located on the southern slopes of the Elburz Mountains, to the east of Tehran. Near its source, as the River is fed mainly by the melting of the winter snow and flows over tuffs and schists, its carbonate‐enriched water can induce soil alkalinization. The Djajerud River runs from its source across a gypsum and marl piedmont. Gypsum is dissolved and modifies the chemical quality of the waters, which lose their alkaline character and get more salty. These sulphate‐rich flows are less damaging because soil degradation hazards in the region are related more to salinization than to alkalinization.

The Djajerud River waters next seep deep into a permeable deposition fan and feed water‐tables which merge into the groundwaters of the Varamin Plain (which are also fed by chloride‐rich waters from other sources). The chemical character of the Djajerud‐River changes in this section, developing a marked sodium chloride salinity. The soils in this part of the Basin, due to the high groundwater salinity, have poor drainage which prevents any agriculture. The River eventually flows into the highly saline endorrheic Daryachehnamak Lake.

The concept of residual alkalinity is used to examine the chemical composition of the Djajerud River along its course and affords the determination of the soil degradation hazard in the various parts of the Basin.
A risk analysis methodology for assessing natural resources degradation
Authors: Cincotta R. , Péarez‐Trejo F.
Published: February 2007

Risk analysis has been employed, amongst other things, both to estimate the probability of future water demand emergencies in reservoir systems (using simulation modelling), and to estimate environmental and public health risks (using empirical data). We assert that this framework, when coupled with simulation modelling, can be applied to examine and compare the impacts of resource exploitation, land use and production strategies which may cause land degradation. Our representation of risk analysis relies on the assumption that each land use strategy is associated with a risk of the system (i.e., social system, production system, ecosystem) attaining a subjectively unacceptable environmental condition (e.g. poor human nutrition, crop failure, degradation of a natural resource) sometime during a management planning period. The research methodology entails: (1) the identification of critical variables in the social and biological environment that are affected by exploitation and management of resources; (2) the identification through interviews, surveys, and research of regions of unacceptability in these variables that determine the dynamics of local environmental degradation; (3) the translation of resource policy and practice into a computer model of impact on the resource system; (4) many iterations of simulation of the system to determine the ‘risk of failing’ in each of the critical variables. The presentation of risk probabilities to decision‐makers represents a reduction of many simulations into an understandable estimate of environmental impact. More importantly, risk analysis is potentially a learning tool for human system studies, and an interface for applied social science and ecological research.
Effects of wildfire on a semidesert riparian woodland along the Turkwel river, Kenya, and management implications for turkana pastoralists
Authors: Oba Gufu
Published: February 2007

Regeneration following a wildfire in a semidesert riparian woodland near the Turkwel River, Kenya was monitored from 2nd June, 1987 to 6th July, 1988. The pre‐fire tree density was 417 plants ha−1 and the canopy cover was 36.5 per cent ha−1. Hyphaene compressa (a palm) accounted for 93 per cent of total density and Acacia tortilis 6.9 per cent. A tortilis contributed a pre‐fire aboveground fuel biomass of 64.92 t ha−1, while H. compressa provided 23.35 t ha−1. The wildfire reduced tree canopy cover to about 7.0 per cent and resulted in a 100.0 per cent top‐kill of A. tortilis and 24.0 per cent for H. compressa. Seed germination of A. tortilis and canopy density of H. compressa saplings were stimulated by the wildfire. The post‐fire A. tortilis seedling density was 9 554 ha−1 compared to the pre‐fire density of 213 plants ha−1. Canopy cover of palms in the burnt area increased by 457.0 per cent, while crown heights increased by 100.0 per cent between the sampling dates. Where H. compressa palms were not top‐killed, recovery following the post‐burn period resulted in higher foliage yield compared to unburnt palms. In reproductive palms, burning delayed fruit production although the effect may not be long lasting.

The impact of wildfire on this Turkwel riparian woodland has important management implications. Elimination of pod‐bearing A. tortilis by fire creates acute shortage of a critical dry season forage for Turkana livestock, while loss of woody cover results in destruction of riparian habitats.
Slow progress with integrated rural development programmes in Kenya's arid and semiarid lands
Authors: Adams M. E.
Published: February 2007

Integrated rural development programmes (IRDPs) in Kenya's Arid and Semiarid Lands (ASAL) arose out of a recognition that they had been neglected in the past and that levels of poverty, the need to increase production and the threat of environmental degradation merited special attention. The primary goal of the IRDP activities was to increase agricultural productivity, thereby contributing to food self‐sufficiency. This goal was reflected in the heavy concentration of resources in natural resource development. Such concentration was frequently at the cost of the development of human resources. Similarly, investment in physical infrastructure and in small‐scale industry was neglected. It was expected that IRDPs would be planned and implemented at the District‐level and would assist in the establishment of district administrative capacity. Participatory planning at the local level was considered a prerequisite to effective and sustainable integrated development. Sadly, IRDPs have been largely unsuccessful in both primary goals. While the reasons for failure are complex, it appears that two key issues stand out: (a) assumptions about the ability of government agricultural services to develop the potential of the ASAL were unrealistic, and (b) there was a lack of real devolution of power to district administrations, and more noticeably, to subdistrict levels. Despite the difficulties, the attraction of IRDPs to the ASAL remain strong. In a time of declining government budgets, they provide a means of getting funds to the district‐level and of catering for the special problems of semiarid environments. The continuing justification for IRDPs may be summarized as follows: (a) there is still a real problem of feeding a growing population in ASAL districts and in high agricultural potential zones; (b) without IRDPs in ASAL districts, standards of living would certainly fall; (c) this may prompt out‐migration from ASAL areas into high potential zones; (d) such out‐migration would occur in the context of increasing land pressure and rising unemployment in high‐potential areas; (e) IRDPs, by sustaining populations within ASAL districts, could contribute to food security in high‐potential areas; (f) IRDPs might also contribute to food security in ASAL districts themselves, by strengthening traditional production systems in these areas. The primary goal is to sustain the populations in ASAL districts by improving their food security. Although natural resource management is still necessary, there must be increasing attention paid to human resource development. Only then can a true transfer of power take place to ASAL districts, whereby their people effectively participate in overcoming and managing local problems.
Applications and limitations of chernobyl radiocaesium measurements in a carpathian erosion investigation, Poland
Authors: Higgitt D. L. , Froehlich W. , Walling D. E.
Published: February 2007

The bomb‐test fallout radionuclide caesium‐137, has found increasing application in geomorphological investigations of soil erosion. Comparatively little work has investigated the potential for using 134Cs and 137Cs derived from the 1986 Chernobyl accident. Results are reported from an agricultural foothill environment in the Beskidy Mountains of southern Poland. The high degree of spatial variability associated with Chernobyl fallout deposition poses considerable limitations on the potential for using radiocaesium measurements to elucidate detailed patterns of soil loss. Despite this problem, the redistribution of radiocaesium from field plots to terrace edges suggests a means for estimating the overall budgets for sediment transfer on cultivated slopes.
Spatial modelling of dryland salinization potential in Victoria, Australia
Authors: Ive J. R. , Walker P. A. , Cocks K. D.
Published: February 2007

The goal of the project discussed in this paper is to produce small‐scale maps of dryland salinization potential for Victoria, Australia; maps which putatively identify areas where salinization effects might be expected to worsen or where effects have yet to become evident. This paper assumes: (a) that current stream salinity levels can be modelled empirically using a relationship reported by Greig and Devonshire (1981), and (b) that a subset of these levels are indicative at an early stage of the maximum long‐term severity (meaning extensiveness) of proximate dryland salinization should water‐tables rise. This paper uses computer induction to relate modelled stream salinity to observed salinization and hence to dryland salinization potential.
Design and effectiveness of permeable infiltration dams in Burkina Faso
Authors: Vlaar J. C. J.
Published: February 2007

This paper reports on research in the Kongoussi Region of Burkina Faso, on permeable infiltration dams, which sought to establish their agricultural and hydrological impact, and to develop criteria for their most effective design. From these studies it appears that, depending on rainfall characteristics, the sorghum grain yields upstream of these dams were 0‐7 t ha−1 to 1‐7 t ha−1 higher than those obtained in valley bottom plots not benefitting from such structures. The difference in yield was most marked in relatively dry years. The hydrological impact appeared to be limited, and the impact on groundwater negligible. As for the design criteria, it appeared that the existing methods of Rodier‐Auvray and Rodier‐Ribstein for estimating runoff floods with a recurrence interval of ten years, are applicable to small catchment areas. Dimensions of a dam can thus be calculated. Other design criteria have been determined in a more qualitative manner and are also presented.
Political ecology of wildlife conservation in the Mt. Meru area of Northeast Tanzania
Authors: Neumann R. P.
Published: February 2007

The wildlife conservation problems in Tanzania are examined from a political ecology perspective. The analysis is historical, exploring the establishment of national parks under British colonial rule and the tightening of state control over access to resources at the expense of customary rights. Examples are presented from the Mt. Meru area of north‐eastern Tanzania. During the colonial period, the formal political debate over land and resource rights was conducted without the participation of African peasants. After independence the state continued to assert control over resource access unilaterally. As Meru peasants have effectively been shut out of the formal political process, their only recourse for defending the loss of access to natural resources is everyday forms of resistance, including de facto alliances with commercial poachers and ‘foot dragging’ in regards to compliance with conservation laws. Consequently there is little local support for current wildlife conservation policies on Mt. Meru and wildlife populations have declined in the 30 years since Arusha National Park was established there.
Land degradation and livestock production in Zimbabwe's communal areas
Authors: Scoones I.
Published: February 2007

This paper considers evidence of land degradation and its impact on livestock production systems in the communal areas of southern Zimbabwe. Various measures of rangeland degradation, using both primary and secondary production indicators, are examined. An apparent contradiction emerges between the high observed levels of soil erosion and the lack of impact on livestock production, as measured by population density trends, cattle production parameters, cumulative stocking levels and extraction rates. Farmers' observations of land degradation processes support the quantitative data. A possible resolution of the contradiction lies in an assessment of the spatial and temporal dimensions of degradation patterns; this points to the fact that current erosion is concentrated in areas that are not key grazing resources for cattle. The analysis suggests an agenda for degradation research that concentrates on evaluating the time span over which economic impacts of soil erosion are felt and assessing the spatial pattern of soil loss, with a special focus on key grazing resource patches.
Geographical information system techniques in land use assessment within landscape types in Eastern Poland
Authors: Ołdak A.
Published: February 2007

Agricultural land use in much of Poland is based on traditional methods in which innovation plays a small part. The recent economic changes which have swept through Poland will result in many new opportunities for farmers as new crops, new marketing techniques and new markets become available. Intensification of agricultural land (and forestry) land use can be achieved to meet the growing demand for indigenously produced foodstuffs and timber and, at the same time, allow an increase in income generation (in raw and value‐added products) especially from the export market. Intensification of output must be based on sustainable and environmentally friendly methods with minimal reliance on imported fertilizers and pesticides. This paper explains how a database consisting of soil, topography, land use and vegetation data has been used to generate a series of potential land use maps for a small area (25 km2) of Eastern Poland in which different levels of management inputs have been applied. A prime objective of this work has been the development of a sustainable agroforestry system based on the assessment of the landscape's natural conditions. The system, when fully developed, should allow effective economic management of the area with depletion of the environmental resource base reduced to a minimum. The results of this study rely on the use of computer‐generated maps prepared with a widely available geographical information system.