bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of providing a polyunsaturated fatty acid-rich protected fat to lactating goats on growth and body composition of suckling goat kids
Authors: Sanz Sampelayo M.R. , Fernández J.R. , Ramos E. , Hermoso R. , Gil Extremera F. , Boza J. 
Published: May 2006

AbstractThe aim of this study was to investigate the possibility of improving the composition of goat meat, in terms of the fatty acid composition of the different fat deposits. For this purpose, we used two groups of 12 female goats each of which had recently undergone a double birth. The animals were maintained under semi-extensive conditions and trough-fed with a concentrate that was either non-supplemented or supplemented with 50 g/kg of polyunsaturated fatty acids (PUFA)-rich fat protected against ruminant metabolism. The kid goats born to each group were suckled by their dams and a representative sample of each was slaughtered at 45 days after birth. The milk produced by the dams receiving the fat-supplemented diet contained fat with a lower content of saturated fatty acids and a higher content of n-3 PUFA, trans-C18: 1 and CLA. The kid goats suckled by these dams grew faster and the legs of the carcasses presented greater muscular development compared with the non-fat-supplemented diet group. The cover, intermuscular and intramuscular fat presented a different fatty acid composition, with a higher proportion of n-3 PUFA, trans C18: 1 and CLA, while that of n-6 PUFA remained unchanged. The change in the lipid metabolism of the kid goats was made evident by the blood levels of certain biochemical parameters. We discuss the improvement in the quality of the meat obtained, taking into account the feeding strategy provided and the class of animal in question.
Cow-dung colonization and decomposition following insect exclusion
Authors: Lee C.M. , Wall R. 
Published: May 2006

AbstractThe rate of dung-pat degradation in cattle pastures in south west England was examined between May and September 2002, using batches of standardized, 1.5 kg, artificially-formed cow pats. In pats in which insects were allowed free access, the rate of disappearance, measured as ash-free dry weight, was faster in spring than summer and the loss of organic matter ranged between 0.69 and 1.99% per day, equating to an estimated time for complete disappearance of 57–78 and 88–111 days in spring and summer, respectively. To assess the role of colonizing insects on decomposition, six batches of pats were constructed and either left uncovered or, using fine mesh cages, were covered for 2, 7 or 14 days following deposition to exclude colonizing insects, after which they were uncovered. After 35 days all pats were then retrieved from the field, the composition of the invertebrate community within each pat was determined and the degree of degradation, measured as ash-free dry weight, was assessed. Covered pats had significantly higher rates of ash-free dry weight loss than uncovered pats. From the 180 pats that were recovered and searched, larvae ofAphodius(Coleoptera: Scarabaeidae) were the most numerous taxon collected (1435 individuals).Aphodiuslarvae were significantly more abundant in pats that remained uncovered or were covered for 2 days only, compared to pats that had been covered for 7 or 14 days. The results show that the exclusion of insects for as little as two days following deposition causes a significant reduction in both the insect population and the subsequent rate of pat degradation.
Morphological Alteration Caused by Brassinosteroid Insensitivity Increases the Biomass and Grain Production of Rice
Authors: Morinaka Yoichi , Sakamoto Tomoaki , Inukai Yoshiaki , Agetsuma Masakazu , Kitano Hidemi , Ashikari Motoyuki , Matsuoka Makoto 
Published: May 2006

Abstract
The rice (Oryza sativa) dwarf mutant d61 phenotype is caused by loss of function of a rice BRASSINOSTEROID INSENSITIVE1 ortholog, OsBRI1. We have identified nine d61 alleles, the weakest of which, d61-7, confers agronomically important traits such as semidwarf stature and erect leaves. Because erect-leaf habit is considered to increase light capture for photosynthesis, we compared the biomass and grain production of wild-type and d61-7 rice. The biomass of wild type was 38% higher than that of d61-7 at harvest under conventional planting density because of the dwarfism of d61-7. However, the biomass of d61-7 was 35% higher than that of wild type at high planting density. The grain yield of wild type reached a maximum at middensity, but the yield of d61-7 continued to increase with planting density. These results indicate that d61-7 produces biomass more effectively than wild type, and consequently more effectively assimilates the biomass in reproductive organ development at high planting density. However, the small grain size of d61-7 counters any increase in grain yield, leading to the same grain yield as that of wild type even at high density. We therefore produced transgenic rice with partial suppression of endogenous OsBRI1 expression to obtain the erect-leaf phenotype without grain changes. The estimated grain yield of these transformants was about 30% higher than that of wild type at high density. These results demonstrate the feasibility of generating erect-leaf plants by modifying the expression of the brassinosteroid receptor gene in transgenic rice plants.
A comparison of daphnid gut particles with the sestonic particles present in two Thames Valley reservoirs throughout 1970 and 1971
Authors: NADIN‐HURLEY C. M. , DUNCAN A. 
Published: May 2006

SummaryThe numerically most abundant component of the seston in two of the Thames Valley storage reservoirs of the Metropolitan Water Board consisted of flocculent organic material which, together with the hyaline, transparent and blackened particles, formed the non‐living sestonic fraction. The abundance of bacterio‐plankton was estimated from plate counts which are known to provide an under‐estimate of the bacteria present. The phytoplankton consisted of the larger flagellates present throughout the year together with a seasonal succession of algae in much greater numbers, namely the smaller flagellates, diatoms, colonial greens, Tribonema and Anabaena.A seasonal analysis of the gut contents of Daphnia magna, D. pulex and D. hyalina (occurring as important grazers in the reservoirs), revealed the presence of organic particles throughout the year plus cells or filaments of the prevailing alga at different seasons. During the summer, there were periods when the guts contained recognizable animal and plant debris. Flagellate and bacterial remains were never seen intact in the guts although these were abundant in the seston during early spring. The filamentous Tribonema was ingested when large crops of it were present.The most frequent size of ingested particle was between 1–2 μm and up to 60% of the animals examined contained particles which were neither longer nor wider than 20μm. Most of these animals ranged between 0·5–1·9 mm in length. A limiting factor for ingestion was thought to be width rather than length of particle and most very large particles found in the gut were long narrow and pliant filaments like Tribonema, or gelatinous colonial green algae, or flexible, foldable crustacean filtering limbs. There appeared to be no difference in the nature or size of particle ingested by the three different species of daphnids and any difference in maximal particle width observed was more likely to be related to body size than to species of consumer.
Carbon, nitrogen, and phosphorus dynamics during leaf decay in nutrient‐enriched stream microecosystems
Authors: HOWARTH ROBERT W. , FISHER STUART G. 
Published: May 2006

SummaryWe investigated the effects of long‐term enrichment with nitrate, phosphate, and nitrate+phosphate on the first 5 weeks of leaf detritus processing in laboratory stream microecosystems. Enrichment with nitrate+phosphate accelerated leaf weight loss and increased rates of respiration associated with the leaves. However, whole‐system respiration was little changed from that observed in the control stream since respiration in the water was greatly reduced. Enrichment with phosphate alone had little effect except to lower respiration associated with leaf discs. Enrichment with nitrate alone also decreased leaf‐disc respiration but resulted in a greatly increased rate of respiration in the water. Net leaching and fragmentation of carbon from the leaves was also increased by nitrate enrichment.Nitrogen and phosphorus levels in leaf material were little affected by enrichment with nitrate or phosphorus alone. Leaves in those streams and in the control stream released nitrogen and phosphorus to the water. In contrast, percent nitrogen and phosphorus increased greatly in the leaves in the stream enriched with both nitrate and phosphate. The leaves in this system immobilized both nitrogen and phosphorus from the water.We also studied the importance of nitrogen fixation as a vector for nitrogen incorporation associated with leaf decomposition in streams. Somewhat surprisingly, fixation by microbes associated with the leaves and by microbes suspended in the water occurred under all three experimental enrichment treatments as well as in the control, casting doubt on the effectiveness of nitrate in inhibiting nitrogenase synthesis in nature. However, N2‐fixation is only a minor source of nitrogen for leaves decaying under the conditions studied.
Effectiveness of an artificial substrate for sampling macroinvertebrates in small streams
Authors: ROBY K. B. , NEWBOLD J. D. , ERMAN D. C. 
Published: May 2006

SUMMARY.
Factors affecting invertebrate colonization of samplers consisting of twenty‐five 5‐cm diameter porcelain balls were studied in small northern California streams. Peaks in diversity, in number of individuals and in taxa, occurred after 2—4 weeks in each of four 10‐week colonization runs. Most variation in number of organisms was correlated with increases in organic detritus. Time was the second most important variable.The average coefficient of variation in total numbers collected from the artificial sampler was 0.40, slightly less than the average 0.56 for the Surber sampler. Published coefficients of variation for artificial substrates range from 0.109 to 0.849, which are similar to values reported from work with the Surber sampler. We had several practical difficulties with the artificial substrates. Samplers were lost, became clogged or buried, supported vertebrate predators and were costly. The samplers also collected some organisms in greater proportion than their occurrences in the natural substrate. In sampling small streams these disadvantages (compared to a Surber sampler) outweigh the slight reduction in sampling variability.
Effects of diet, body size, age and temperature on growth rates in the amphipod Gammarus pulex
Authors: SUTCLIFFE D. W. , CARRICK T. R. , WILLOUGHBY L. G. 
Published: May 2006

SUMMARY.
Increase in body wet weight of Gammarus pulex fed on decaying elm leaves was followed to senescence and death. Growth in juveniles was approximately exponential; from birth to death it conformed to a logistic growth curve, with maximum absolute increments in weight about half‐way through a life span of 350–450 days at 15°C. Some individuals lived longer, for up to 640–700 days. The instantaneous or specific growth rate was maximal near birth, at c. 5–6% wet wt day−1, and declined exponentially with increasing size and age. Over the range 4.7–14.8°C there was a log‐log relationship between temperature and specific growth rate. Growth was maximal at 20°C in newborn animals and at 15°C in 6–9‐mg animals.The specific growth rate of young individuals was fastest on decaying leaves of elm with a well developed flora of fungi and other microorganisms. Leached elm leaves without this flora supported growth at a lower rate. The latter diet was sufficient for survival and growth of newborn individuals; detritus, faeces or other food items were not needed. Isolated specimens grew as fast as those kept in groups. Growth was generally slower on leached leaves of oak and sycamore. In newborn animals fed on the fine roots of aquatic plants (Veronica, Rorippa and Glyceria), growth was as fast as on decaying elm leaves; growth on the green living leaves of the plants was slower, as on detritus from two streams and on a pure culture of an aquatic fungus.Consumption of leached elm leaves was related to leaf thickness. In a full gut the wet weight (1.34–1.37 mg) and volume (3.8–4.1 mm3) (for 20‐mg animals) was independent of leaf thickness but dependent on animal size, increasing 4‐fold over the range 2–50 mg body wt. Daily consumption (dry wt) was approximately equivalent to 50% body dry wt at 5 mg and 20% at 50 mg body wet wt. Individuals fed on thick leaves ingested 50% more dry weight per day and absorbed more in the gut than when fed on thin leaves, but the relative efficiency of absorption was the same at 36–59% for 10–20‐mg animals. Weight‐specific absorption in the gut was highest in juveniles and decreased with increasing body weight; relative efficiency of absorption was generally lower in the larger individuals. Assuming an energy value of 5 cal mg−1 dry wt for elm leaves, daily mean energy intake by absorption in thegutof G. pu/ex was2.2 cal mg−1 animaldry wt (9.2 J mg−1) in individuals of 0.4 mgdry wt (2 mg wet wt), decreasing to 0.3 cal mg−1 (1.3 J mg−1) at 10 mg dry wt (50 mg wet wt).Growth in Gammarus is briefly reviewed in the hght of work on other animals and it is emphasized that all aspects of feeding, growth and metabol‐ism should be specifically related to size and age of the individuals, using well defined diets.
Some effects of organic pollution on the distribution and seasonal incidence of Chironomidae in riffles in the River Cole
Authors: DAVIES L. J. , HAWKES H. A. 
Published: May 2006

SUMMARY.
The effects of a sewage effluent discharge into the River Cole, Birmingham, were determined by regular collections of water and biological samples from six comparable stations, one above and five below the sewage effluent. The effluent reduced the dissolved oxygen concentration and increased the ammonia, orthophosphate and BOD concentrations in the water. The effects were much more severe during the summer.The Chironomidae were very important constituents of the benthic macroinvertebrate community at the stations downstream of the effluent. Larval densities of over 30,000 m−2 were recorded. Eleven species were common and of these Chironomus riparius was the most tolerant. There was considerable variation in the seasonal incidence of the different species. Brillia longifurca was most abundant in the spring while Cricotopus bicinctus was most abundant in the summer. Brillia longifurca, Paratrichocladius rufiventris, Prodiamesa olivacea, Micropsectra atrofasciata and Eukiefferiella claripennis had three peaks in numbers of larvae during the year.The increase in the polluted state of the river in the summer resulted in changes in the chironomid populations. Some were suppressed, e.g. E. claripennis, while C. riparius extended its range and achieved maximum abundance further downstream during the summer.
The distribution of Naididae (Oligochaeta) in the littoral zone of selected lakes in North Wales and Shropshire
Authors: McELHONE MALCOLM J. 
Published: May 2006

SUMMARY. The distribution of twenty species of Naididae found in seventeen lakes in North Wales and Shropshire is described. Fewer species were observed in the mountain lakes in Snowdonia in comparison to the more productive lakes of Anglesey and Shropshire.Substrate was an important factor influencing the distribution of naids within lakes, A small number of sexually mature individuals was found in more productive lakes in the summer and autumn months. Sexually mature individuals of Stylaria lacustris were cultured in the laboratory; the population doubled its numbers, by asexual reproduction, in 12 days at 15°C. In Llyn Coron a natural population of S. lacustris doubled its numbers in 40 days. The gut contents of S. lacustris consisted of periphyton.
Studies on Chironomidae in experimental recirculating stream systems. I. Orthocladius (Euorthodadius) calvus sp.nov.
Authors: PINDER L. C. V. 
Published: May 2006

SUMMARY.

Large nutnbers of a previously undescribed species of Orthocladius (Euorthocladius) were amongst the first animals to colonize a pair of artificial recirculating streams.
The larva, pupa and adults are described and compared with O. (E.) thienemanni which occurs abundantly in adjacent streams.
Comparability of introduced tiles and natural substrates for sampling lotic bacteria, algae and macro invertebrates
Authors: LAMBERTI GARY A. , RESH VINCENTH. 
Published: May 2006

SUMMARY.

Benthic microflora (bacteria and algae) and macro invertebrates on two types of introduced substrates, unglazed clay tiles and sterilized rocks, were compared quantitatively with natural rocks in a third‐order stream. Big Sulphur Creek, California, U.S.A.
Exposure periods ranging from 28 to 153 days for introduced substrates indicated that tiles accurately represented bacterial density, chlorophyll a, and macro invertebrate density and species composition of natural rocks within 28 days; phaeophytin and total organic material (as ash‐free dry weight) were accurately represented within 63 days. In contrast. sterilized rocks required a 63 day exposure to simulate most of the above natural‐rock features.
Tiles reduced sampling variability (i.e. increased precision) when compared with either natural or sterilized rocks, especially the variability associated with algal measurements. In benthic studies where a sufficiently long exposure period is possible (1‐2 months), introduced substrates can reduce the effort and cost of benthic sampling while minimizing habitat disruption.
Variation in the intersetular distance on filter setae of Simocephalus vetulus (O. F. Miiiler) (Crustacea‐Cladocera)
Authors: MANGALO HANA H. 
Published: May 2006

SUMMARY. 1. The intersetular distance (filter mesh‐size) of adult Simocephalus showed a two‐fold seasonal variation in each of two ponds. In one pond the maximum intersetular distance was found in March, while in the other pond the maximum intersetular distance was found in September.2. These seasonal changes in intersetular distances was positively correlated with changes in phytoplankton biomass (estimated by chlorophyll a). As food concentration increased (estimated by chlorophyll a) the mean intersetular distance of adull Simocephalus also increased.3. The intersetular distances on fillcring setae also vary with the size of animals. There is a linear relation between body length and intersetular distance.4. Variation in the intersetular dimension with body size may decrease competition tor food between adults and young.
The response of Asterionella formosa to germanium: implications for the germanium inhibition technique for estimating diatom contribution to community productivity
Authors: OSTROFSKY MILTON L. , BELLMER ANNE E. 
Published: May 2006

SUMMARY. 1. The effect of added germanium on the assimilation of carbon by Asterionella formosa Hass. in mixed phytoplankton assemblages was measured weekly from July to December 1981 by auto‐radiography.2. Contrary lo a major assumption of the germanium‐inhibition method of partitioning primary productivity, the germanium‐induced inhibition varied considerably and with no apparent pattern.3. Inhibition values determined for laboratory cultures are probably not indicative of the responses of in situ populations, and serious errors can occur in estimating diatom contribution to total community photosynthesis. This places severe limitations on the use of the method.
Estimation of nektonic insect populations
Authors: BENDELL BARRY E. , McNICOL DONALD K. 
Published: May 2006

SUMMARY 1. A water column sampler is described for obtaining absolute population estimates of nektonic insects in shallow waters.2. Relative population estimates were obtained for Corixidae (Hemip‐tera) and Buenoa(Hemiptera: Notonectidae) using a standardized sweep net procedure and compared to absolute estimates from column samples. These two types of estimates were highly correlated among lakes.3. Simultaneous prediction and tolerance intervals for predictions from linear regressions indicated that reliable absolute population estimates generally cannot be expected from relative estimates
Time series analysis of water quality data from Lake Ontario: implications for the measurement of water quality in large and small lakes
Authors: HARRIS GRAHAM P. 
Published: May 2006

SUMMARY 1. The normal strategy of monitoring water quality is to sample such parameters as chlorophyll no more than weekly. A preferable strategy is to first define the natural periodicities in the water body and then to set up a sampling scheme that takes into account the natural scales of variance in physical, chemical and biological parameters. Failure to do so leads to aliased and biased estimates of means and variances and an inability to interpret the underlying physical and biological mechanisms.2. The natural scales of variance vary with basin size. In lakes, physical and biological processes overlap at scales of from 1 to 15 days. Time series analysis of daily data from Lake Ontario and other lakes showed how the means and variances of the data sets were determined by the physical and biological processes in the water columns and displayed the fundamental lags in the systems. Even in small lakes and reservoirs, advective processes were of great importance. Advection became the dominant process in Lake Ontario. Time lags and advection made simple correlations of physical and biological parameters meaningless.3. Decimation of the daily data sets revealed the statistical dangers of less frequent sampling. The desirable frequency of sampling was shown to be a function of the physics of the mixed layer, the turnover times of the nutrient pools, and the biological activity. Data from the three lakes graphically demonstrated the inadequacy of normal sampling frequencies.
Growth rate of the aquatic moss Rhynchostegium riparioidesin Northern England
Authors: KELLY M. G. , WHITTON B. A. 
Published: May 2006

SUMMARY 1. The rale of shoot growth in Rhynchostegium riparioideswas measured at monthly intervals over a 12‐month period at four upland sites in the Northern Pennines. Changes were recorded by observations attached pieces of cotton. Detectable growth was found in each month, with the maximum in spring (up to 2.31 mm week−1) and minimum in winter (1.12 mm week−1); there was a second smaller peak in the autumn.2. Growth rate was related strongly to several environmental variables, including spot measurements of water temperature (positive) and mean monthly precipitation (negative). A regression equation based on these two variables accounted for 5% of the variation recorded.3. Total shoot growth over the 12‐month period ranged from 33.4 to 73.3 mm, corresponding to an increase in mass of 22.9 and 120.8 mg, respectively.
Reproduction in an Irish lake population of the crayfish Austropotamobius pallipes (Lerehoullet)
Authors: WOODLOCK BRIAN , REYNOLDS JULIAN D. 
Published: May 2006

SUMMARY. 1. Mature crayfish were collected in 1984 from an alkaline Irish lake before and after the mating season.2. There was some correlation between frequency of mating and decrease in vasa deferentia weight in captive males, but in the field vasa deferentia weight losses were highly variable. The data indicate that one third of adult males may not have mated in the wild.3. All females appear to have spawned, whether or not mated, with an average 85% reduction in ovary weights over the season.4. Pleopodal egg counts directly after laboratory spawning were on average 81% of ovarian counts; in the field, an estimated 50 days after spawning, they were only 61% of estimated ovarian egg numbers.5. Average ovarian egg size was positively correlated with female size. Also, larger crayfish had a wider range of egg sizes than smaller crayfish.6. It is suggested that aggression and competition for shelter among brooding females may result in a progressive loss of eggs.