bluuebunny/crossref_metadata_2025_split huggingface dataset:
The influence of climate on the distribution of monogeneans of anurans in Nigeria
Authors: Aisien S.O. , Salami L.A. , Obaro F.E. , Erakpoweri S.O. 
Published: May 2004

AbstractInvestigations undertaken on the monogeneans of amphibians in Nigeria have shown that host ecology has an influence on the distribution of these monogeneans. Amphibians from humid environments of the rainforest, a freshwater swamp and mangrove harboured no monogeneans, whereas those occurring in drier conditions in the savannah-mosaic and guinea savannah yielded five species of polystomatid parasites: Polystoma prudhoei from Bufo regularis, Polystoma galamensis from Rana galamensis, Eupolystoma alluaudi from Bufo regularis and Bufo maculatus, and two unidentified Polystoma species from Bufo regularis and Ptychadena oxyrynchus, respectively. Some of these monogeneans appear to have reproduction cycles which are synchronized with those of the hosts. The prevalence of E. alluaudi in Bufo spp. caught in New Bussa (68.4% in B. regularis and 82.3% in B. maculatus) were higher than those reported for this parasite in other locations in West Africa and for Eupolystoma anterorchis in Bufo pardalis from the Cape Flats of South Africa.
Density-dependent effects on the survival and growth of the rodent stomach wormProtospirura muricolain laboratory mice
Authors: Lowrie F.M. , Behnke J.M. , Barnard C.J. 
Published: May 2004

AbstractThe spirurid nematode,Protospirura muricola, is of intrinsic interest as a rodent model of gastric nematode infections. Since worm burdens can be very heavy in nature, density dependent processes may constrain parasite growth. Laboratory mice (BKW) were exposed to varying doses of infective larvae ofP. muricolain the range 5 to 40 third-stage larvae (L3), in four separate experiments in which progressively higher doses were utilized. All mice were culled 60 days after infection and a total of 518 worms (226 male and 292 female worms) was recovered, measured and weighed. Overall survival was 58.9%, but survival declined significantly with increasing dose by approximately 21% (from 66% at 5 L3 per mouse to 52% at 40 L3 per mouse). The length and weight of worms correlated positively in both sexes. Total worm biomass increased linearly with increasing numbers of worms. However, whilst the length and weight of male worms declined with increasing worm burden (8.4 and 24.6% respectively), female worms were less affected, only length showing a significant reduction with increasing parasite burden (16.0%). Therefore, increasing worm burdens impeded growth ofP. muricola, but reduction in length and weight were relatively small in relation to the overall size of this nematode. Increasing worm burdens were associated with loss of host weight and reduction in stomach weight and worm burdens in excess of 20 exerted a measurable cost to the host, which in the field, may be associated with loss of overall host fitness.
Cross-cultural comparison of growth, maturation and adiposity indices of two contrasting adolescent populations in rural Senegal (West Africa) and Martinique (Caribbean)
Authors: Bénéfice Eric , Caïus Nathalie , Garnier Denis 
Published: May 2004

AbstractObjectives:To stress the importance of social and environment (nutritional) factors in determining the growth spurt during puberty and the risk of excessive adiposity, two contrasting adolescent populations, one from a rural area of Senegal (West Africa) and the other from Martinique (French West Indies), were compared.Design:Cross-cultural comparison of contrasting populations. Adolescents from Senegal belonged to a cohort followed up since 1995. Adolescents from Martinique participated in a cross-sectional nutritional survey that covered the entire island.Subjects:A total of 507 adolescents (mean age: 14.3 ± 0.7 years) from Senegal (319 girls and 188 boys) and 703 adolescents from Martinique (351 boys and 352 girls) were surveyed.Results:Differences in growth and maturation were striking: boys in Martinique were 22.7 kg heavier and 20.1 cm taller than boys in Senegal. Differences were less important for girls but still evident: 12.6 kg in weight and 10.5 cm in stature. In Senegal, there were virtually no overweight adolescents, but 18% of girls and 50% of boys could be considered as malnourished. In Martinique, 19% of girls and 23% of boys were overweight or obese. Adolescent girls from Martinique were also sexually more mature than adolescent girls from Senegal. When comparisons were repeated after Senegalese girls reached menarche, differences in weight and body mass index disappeared, but Senegalese girls were still shorter than girls from Martinique.Conclusions:Adolescents are extremely susceptible to nutritional changes and their particular situation needs to be incorporated into nutritional prevention programmes.
A longitudinal assessment of the diet and growth of malnourished children participating in nutrition rehabilitation centres in Accra, Ghana
Authors: Colecraft Esi K , Marquis Grace S , Bartolucci Alfred A , Pulley LeaVonne , Owusu W Bruce , Maetz H Michael 
Published: May 2004

AbstractObjective:To examine the adoption of feeding recommendations among caregivers of children recuperating from malnutrition and assess the determinants of growth of children attending a nutrition rehabilitation centre (NRC) in Accra, Ghana.Design:Longitudinal study in which attendance and maternal programme participation were recorded daily and children's anthropometry and dietary intake were measured at four time points (admission, interim, exit, post-exit) at the NRC and participants' homes.Setting:NRCs at four polyclinics and participants' homes in Accra, Ghana.Subjects:One hundred and eight caregivers and their 116 children referred to an NRC between November 1999 and July 2000.Results:Most caregivers attended the NRC sporadically (effective length of stay was 1.4 ± 0.1 months). Use of NRC-promoted foods in the home after discharge was low due to inaccessibility of the food items, lack of preparation knowledge or money, child preferences and the common practice of purchasing ready-to-eat foods. Although there were significant increases in children's weight-for-age (P = 0.048) and weight-for-height (P = 0.002) Z-scores between enrolment and discharge, most children discontinued programme participation before adequate recuperation.Conclusions:The NRC education did not address the use of street foods for child feeding and was unsuccessful in changing in-home feeding behaviour. The prominence of street foods in children's diets warrants re-evaluation of the NRC's educational approaches to enhance their responsiveness to caregivers' needs and effectiveness for the continued recuperation of malnourished children at home. NRC feeding strategies need improvement to ensure adequate provision of energy and nutrients to support catch-up growth in children.
Definability in the lattice of equational theories of commutative semigroups
Authors: Kisielewicz Andrzej 
Published: May 2004

In this paper we study first-order definability in the lattice of equational theories of commutative semigroups. In a series of papers, J. Ježek, solving problems posed by A. Tarski and R. McKenzie, has proved, in particular, that each equational theory is first-order definable in the lattice of equational theories of a given type, up to automorphism, and that such lattices have no automorphisms besides the obvious syntactically defined ones (with exceptions for special unary types). He has proved also that the most important classes of theories of a given type are so definable. In a later paper, Ježek and McKenzie have “almost proved" the same facts for the lattice of equational theories of semigroups. There were good reasons to believe that the same can be proved for the lattice of equational theories of commutative semigroups. In this paper, however, we show that the case of commutative semigroups is different.
Linking numbers in rational homology 3-spheres, cyclic branched covers and infinite cyclic covers
Authors: Przytycki Józef , Yasuhara Akira 
Published: May 2004

We study the linking numbers in a rational homology

3
3

-sphere and in the infinite cyclic cover of the complement of a knot. They take values in

Q

\mathbb {Q}

and in

Q

(

Z

[
t
,

t

−
1

]
)

{Q}(\mathbb {Z}[t,t^{-1}])

, respectively, where

Q

(

Z

[
t
,

t

−
1

]
)

{Q}(\mathbb {Z}[t,t^{-1}])

denotes the quotient field of

Z

[
t
,

t

−
1

]

\mathbb {Z}[t,t^{-1}]

. It is known that the modulo-

Z

\mathbb {Z}

linking number in the rational homology

3
3

-sphere is determined by the linking matrix of the framed link and that the modulo-

Z

[
t
,

t

−
1

]

\mathbb {Z}[t,t^{-1}]

linking number in the infinite cyclic cover of the complement of a knot is determined by the Seifert matrix of the knot. We eliminate ‘modulo

Z

\mathbb {Z}

’ and ‘modulo

Z

[
t
,

t

−
1

]

\mathbb {Z}[t,t^{-1}]

’. When the finite cyclic cover of the

3
3

-sphere branched over a knot is a rational homology

3
3

-sphere, the linking number of a pair in the preimage of a link in the

3
3

-sphere is determined by the Goeritz/Seifert matrix of the knot.
Initial Response of Butterflies to an Overstory Reduction and Slash Mulching Treatment of a Degraded Piñon‐Juniper Woodland
Authors: Kleintjes P. K. , Jacobs B. F. , Fettig S. M. 
Published: May 2004

Abstract Overstory reduction and slash mulching (ORSM) has been shown to be an effective means for increasing herbaceous cover and diversity in degraded piñon (Pinus edulis) and juniper (Juniperus monosperma) woodlands of north‐central New Mexico. Local fire history, tree age‐class structure, and grazing records suggest that many areas now occupied by dense piñon‐juniper woodlands were formerly more open, with grassy understories that supported well‐developed soils and a fire regime. At Bandelier National Monument, studies are evaluating the use of ORSM treatments as a restoration management tool. In 1999 and 2001, we evaluated the effects of an ORSM treatment implemented in 1997 upon butterfly abundance and species richness between a pair of treated and control watersheds. Butterfly abundance and species richness were significantly greater on the treated watershed in both years, and these measures were correlated with significant increases in forb and grass cover in the treated watershed. Five of the 10 most common nectar and larval host plants had significantly greater cover in the treated watershed, including the legume Lotus wrightii. Our results suggest that the increased herbaceous cover resulting from an ORSM treatment of a single watershed induced a positive, initial response by butterflies. Using butterflies as indicators of site productivity and species richness, our results suggest ORSM is a promising technique for restoring biodiversity in degraded piñon‐juniper woodlands.
Native Alternatives for Non‐Native Turfgrasses in Central Florida: Germination and Responses to Cultural Treatments
Authors: Jenkins Amy M. , Gordon Doria R. , Renda Michael T. 
Published: May 2004

Abstract Little information exists about the establishment of native longleaf pine flatwoods species for use in restoration efforts and as buffers around natural areas in the southeastern United States. Composition of groundcover in these systems is dominated by perennial graminoid species. Vegetation in current buffers is generally non‐native turfgrass that can escape into natural areas, often reducing establishment and survival of native species. Where management objectives involve actively restoring native groundcover or reducing the probability of invasion by these non‐native turfgrasses, identification of native species and restoration methods is needed. We investigated seed germination and establishment of four species native to longleaf pine flatwoods in central Florida and one species native to the adjacent wetland communities. Paspalum setaceum, Panicum anceps, Eustachys petraea, and Eragrostis refracta were directly seeded, and P. distichum was planted as sprigs into three former P. notatum pastures. Irrigation, fertilization, weed control, and mowing treatments were assessed in terms of cover development of the sown species. Paspalum distichum developed the highest percent cover—over 80% in wet areas after 1 year. Mowing had mixed impacts depending on the species, and fertilization never significantly increased cover. Directly seeded species developed sparse cover (0–40%), probably as a result of drought conditions. However, E. petraea and E. refracta appeared more promising for use on rights‐of‐way when using high sowing rates. A second experiment conducted on a roadside included these two species and sprigged P. distichum. Both E. petraea and P. distichum developed more than 45% cover on the roadside. Establishment of these natives from seed or sprigs was significantly enhanced when site preparation effectively reduced the seedbank of other species present in the soil.
Effects of an Intense Prescribed Forest Fire: Is It Ecological Restoration?
Authors: Fulé Peter Z. , Cocke Allison E. , Heinlein Thomas A. , Covington W. Wallace 
Published: May 2004

AbstractRelatively intense burning has been suggested as a possible alternative to the restoration of pre‐European settlement forest conditions and fire regime in mixed conifer forests, in contrast to thinning of trees and light prescribed burning. In 1993 a management‐ignited fire in a dense, never‐harvested forest in Grand Canyon National Park escaped prescription and burned with greater intensity and severity than anticipated. We sampled the burned site and an adjacent unburned site (270 ha each) 6 years after the fire to assess burn effects on tree structure (species composition, size and age distributions, regeneration, and snags), forest floor fuels, and coarse woody debris. Tree structure before fire‐regime disruption (1879 CE) was reconstructed with dendroecological techniques. By 6 years after burn the fire reduced average tree density (331 trees/ha) and basal area (28.5 m2/ha) to levels similar to pre‐European reference conditions (approximately 246 trees/ha and 28.5 m2/ha). Mortality was concentrated in fire‐susceptible species, especially white fir, restoring dominance by fire‐resistant ponderosa pine. Forest floor fuels were reduced, and regeneration by aspen and understory plants was vigorous. Densities of large snags and logs were high. However the fire also killed a high proportion of old‐growth trees, especially aspen. Burning created more spatial variability in forest structure than was present before fire‐regime disruption by killing many trees in some areas of the site but few in other areas. The intentional use of severe burning would be challenging to managers because of the increased risk of escaped fires, but the ecological outcome of this particular wildfire was not inconsistent with ecological restoration goals for this ecosystem type.
Effects of Sewage Sludge on Plant Community Composition in Restored Limestone Quarries
Authors: Moreno‐Peñaranda Raquel , Lloret Francisco , Alcañiz Josep M. 
Published: May 2004

Abstract The effects of sewage sludge, used to improve fertility of replaced soil, on vegetation were studied in limestone quarry restoration. Plant community growing in the first stages after sludge application was surveyed in six quarries of NE Spain. Areas with a mixture of sewage sludge and residual soil were compared to areas where the application consisted only of residual soil (a mixture of previous top soil and mine spoils). Sewage sludge was hypothesized to increase total biomass and cover, modifying species composition and delaying the early successional recover of the community. The results showed that both biomass and plant cover increased because of sewage sludge addition. The floristic composition was dominated by ruderal species that did not show any dependence on sewage sludge application. Convergence on similarity between sludge and control plots was not detected along a 5‐year period. Although species richness was significantly lower in sludge plots, diversity and equitability indexes did not show differences between treatments. The results did not show differences in the proportion of non‐native species. The proportion of legumes was lower in sludge plots. These results show that the plant communities resulting from the addition of sewage sludge to the soil used in limestone quarry restoration have more biomass and cover, but less number of species, and they do not show a clear trend to converge to those areas restored only with non‐amended soil.
Revegetation Methods for High‐Elevation Roadsides at Bryce Canyon National Park, Utah
Authors: Petersen S. L. , Roundy B. A. , Bryant R. M. 
Published: May 2004

Abstract Establishment of native plant populations on disturbed roadsides was investigated at Bryce Canyon National Park (BCNP) in relation to several revegetation and seedbed preparation techniques. In 1994, the BCNP Rim Road (2,683–2,770 m elevation) was reconstructed resulting in a 23.8‐ha roadside disturbance. Revegetation comparisons included the influence of fertilizer on plant establishment and development, the success of indigenous versus commercial seed, seedling response to microsites, methods of erosion control, and shrub transplant growth and survival. Plant density, cover, and biomass were measured 1, 2, and 4 years after revegetation implementation (1995–1998). Seeded native grass cover and density were the highest on plots fertilized with nitrogen and phosphorus, but by the fourth growing season, differences between fertilized and unfertilized plots were minimal. Fertilizers may facilitate more rapid establishment of seeded grasses following disturbance, increasing soil cover and soil stability on steep and unstable slopes. However the benefit of increased soil nutrients favored few of the desired species resulting in lower species richness over time compared to unfertilized sites. Elymus trachycaulus (slender wheatgrass) plants raised from indigenous seed had higher density and cover than those from a commercial seed source 2 and 4 years after sowing. Indigenous materials may exhibit slow establishment immediately following seeding, but they will likely persist during extreme climatic conditions such as cold temperatures and relatively short growing seasons. Seeded grasses established better near stones and logs than on adjacent open microsites, suggesting that a roughened seedbed created before seeding can significantly enhance plant establishment. After two growing seasons, total grass cover between various erosion‐control treatments was similar indicating that a variety of erosion reduction techniques can be utilized to reduce erosion. Finally shrub transplants showed minimal differential response to fertilizers, water‐absorbing gels, and soil type. Simply planting and watering transplants was sufficient for the greatest plant survival and growth.
An Analysis of Vegetation Restoration on Opencast Oil Shale Mines in Estonia
Authors: Pensa Margus , Sellin Arne , Luud Aarne , Valgma Ingo 
Published: May 2004

Abstract We compared four types of 30‐year‐old forest stands growing on spoil of opencast oil shale mines in Estonia. The stand types were: (1) natural stands formed by spontaneous succession, and plantations of (2) Pinus sylvestris (Scots pine), (3) Betula pendula (silver birch), and (4) Alnus glutinosa (European black alder). In all stands we measured properties of the tree layer (species richness, stand density, and volume of growing stock), understory (density and species richness of shrubs and tree saplings), and ground vegetation (aboveground biomass, species richness, and species diversity). The tree layer was most diverse though sparse in the natural stands. Understory species richness per 100‐m2 plot was highest in the natural stand, but total stand richness was equal in the natural and alder stands, which were higher than the birch and pine stands. The understory sapling density was lower than 50 saplings/100 m2 in the plantations, while it varied between 50 and 180 saplings/100 m2 in the natural stands. Growing stock volume was the least in natural stands and greatest in birch stands. The aboveground biomass of ground vegetation was highest in alder stands and lowest in the pine stands. We can conclude that spontaneous succession promotes establishment of diverse vegetation. In plantations the establishment of diverse ground vegetation depends on planted tree species.
Herbicide and Tillage Effects on Volunteer Vegetation Composition and Diversity During Reforestation
Authors: Baer Sara G. , Groninger John W. 
Published: May 2004

AbstractFraxinus pennsylvanica(green ash) is commonly used for reforestation of agricultural lowlands in the midwestern and eastern United States. We evaluated the effects of herbicide (untreated, glyphosate, and sulfometuron methyl) and tillage (tilled and no‐till) onF. pennsylvanicasuccess and composition of associated volunteer vegetation 3 years after the treatment applications and reforestation of a formerly cultivated field in southern Illinois. Tillage had no effect onF. pennsylvanicagrowth, whereas both herbicides increased all measures of tree performance. The response of associated native and non‐native species cover was affected by an interaction between the herbicide and tillage treatments. In the presence of herbicide, cover of native species was greater in the no‐till treatment, whereas non‐native cover was higher in the tillage treatment. Both native and non‐native cover were unaffected by tillage in the absence of herbicide, and there were no differences in cover among the herbicide treatments in the presence of tillage. Total diversity was higher in the tillage treatment than the no‐till treatment, and diversity was lower in the sulfometuron methyl herbicide treatment than the control and glyphosate herbicide treatment. Lower diversity in the sulfometuron methyl treatment was attributed to greater cover of a native perennial grass,Andropogon virginicus(Broomsedge), which was inversely related to total diversity. We conclude that a single glyphosate herbicide application can enhanceF. pennsylvanicagrowth and conserve associated species diversity in this system. Furthermore, species‐specific responses of the associated vegetation should be included in management considerations, particularly if silvicultural treatments influence dominance and diversity in the establishing understory community during reforestation.