bluuebunny/crossref_metadata_2025_split huggingface dataset:
Predicting the impacts of an introduced species from its invasion history: an empirical approach applied to zebra mussel invasions
Authors: Ricciardi Anthony 
Published: May 2003

SUMMARY1. Quantitative models of impact are lacking for the vast majority of known invasive species, particularly in aquatic ecosystems. Consequently, managers lack predictive tools to help them prioritise invasion threats and decide where they can most effectively allocate limited resources. Predictive tools would also enhance the accuracy of water quality assessments, so that impacts caused by an invader are not erroneously attributed to other anthropogenic stressors.2. The invasion history of a species is a valuable guide for predicting the consequences of its introduction into a new environment. Regression analysis of data from multiple invaded sites can generate empirical models of impact, as is shown here for the zebra musselDreissena polymorpha.Dreissena's impacts on benthic invertebrate abundance and diversity follow predictable patterns that are robust across a range of habitat types and geographic regions. Similar empirical models could be developed for other invaders with a documented invasion history.3. Because an invader's impact is correlated with its abundance, a surrogate model may be generated (when impact data are unavailable) by relating the invader's abundance to environmental variables. Such a model could help anticipate which habitats will be most affected by invasion. Lack of precision should not be a deterrent to developing predictive models where none exist. Crude predictions can be refined as additional data become available. Empirical modelling is a highly informative and inexpensive, but underused, approach in the management of aquatic invasive species.
Seasonal and diel patterns of invertebrate drift in different alpine stream types
Authors: Hieber Mäggi , Robinson Christopher T. , Uehlinger Urs 
Published: May 2003

SUMMARY1. We examined the seasonal and diel patterns of invertebrate drift in relation to seston and various habitat characteristics in two each of four different kinds of alpine streams [rhithral (snow‐fed) lake outlets, rhithral streams, kryal (glacial‐fed) lake outlets and kryal streams]. Samples were collected at four times of the day (dawn, midday, dusk and midnight) during three seasons (spring, summer and autumn).2. Habitat characteristics differed mainly between rhithral and kryal sites, with the latter having higher discharge and turbidity, lower water temperature, and higher concentrations of ammonium, and particulate and soluble reactive phosphorus. Seasonality in habitat characteristics was most pronounced for kryal streams with autumn samples being more similar to rhithral sites.3. The concentration of seston was lowest in the glacial‐influenced lake outlets and slightly higher in the stream sites; no seasonal or diel patterns were evident.4. The density of drifting invertebrates averaged less than 100 m−3 and was lowest (<10 m−3) at three of the four kryal sites. Taxon richness and diversity were lowest at rhithral lake outlets. Chironomidae dominated the drift as well as benthic communities and <30% of benthic taxa identified were found in the drift.5. Drifting invertebrates showed no consistent seasonal pattern. However, density tended to be highest in spring at rhithral sites and in autumn at kryal sites. No diel periodicity in drift density was found at any site and the lack of diel pattern may be a general feature of high altitude streams.6. Glacially influenced habitat parameters were a major factor affecting drift in these alpine streams, whereas no clear differences were observed between streams and lake outlets. Our findings indicate that invertebrate drift in alpine streams is primarily influenced by abiotic factors, and therefore, substantially differs from patterns observed at lower altitude.
Oviposition in three species of limnephiloid caddisflies (Trichoptera): hierarchical influences on site selection
Authors: Hoffmann A. , Resh V.H. 
Published: May 2003

SUMMARY1. Oviposition site selection was studied in three trichopteran species; an undescribed species of Hydatophylax (Limnephilidae), Onocosmoecus unicolor (Limnephilidae) and Neophylax rickeri (Uenoidae), in two Coastal Range streams in California, U.S.A.2. Hydatophylax sp. egg masses were generally found at or above the water surface on substrata near the bank in pools, where undercut banks, overhanging vegetation and rocks shaded attachment sites and provided wind protection. Onocosmoecus unicolor females deposited their egg masses exclusively above the water on moist emergent wood. The egg masses of N. rickeri were almost exclusively found in high velocity areas of riffles, where females oviposited under water and attached their egg masses to the submersed undersides of unembedded, protruding stones with large emergent surfaces.3. For Hydatophylax sp. and N. rickeri, a hierarchical selection scheme is proposed in which females use cues at three different spatial levels (stream, stream subunit, substratum) to choose oviposition sites. Females of O. unicolor seemed to choose at only two different levels of spatial resolution (stream, substratum).4. The formation of large aggregations of egg masses in N. rickeri and O. unicolor suggests that females actively choose oviposition sites where conspecific egg masses are already attached. The clustering of egg masses may minimise the risk of predation through the dilution effect, because egg masses of N. rickeri and O. unicolor are both attacked by dipteran predators.5. Females of the three Trichoptera species studied are able to make a clear choice of oviposition site in the heterogeneous stream environment. In comparison with other stream microhabitats, these are characterised by stable and relatively predictable environmental conditions during the time of egg development, which is seen as the main selective pressure leading to the observed egg‐laying behaviour.
Can C4 plants contribute to aquatic food webs of subtropical streams?
Authors: Clapcott Joanne E. , Bunn Stuart E. 
Published: May 2003

Summary1. Recent stable isotope studies have revealed that C4 plants play a minor role in aquatic food webs, despite their often widespread distribution and production. We compared the breakdown of C3 (Eucalyptus) and C4 (Saccharum and Urochloa) plant litter in a small rain forest stream and used laboratory feeding experiments to determine their potential contribution to the aquatic food web.2. All species of litter broke down at a fast rate in the stream, although Urochloa was significantly faster than Eucalyptus and Saccharum. This was consistent with the observed higher total organic nitrogen of Urochloa compared with the other two species.3. The breakdown of Urochloa and Saccharum was, however, not associated with shredding invertebrates, which were poorly represented in leaf packs compared with the native Eucalyptus. The composition of the invertebrate fauna in packs of Urochloa quickly diverged from that of the other two species.4. Feeding experiments using a common shredding aquatic insect Anisocentropus kirramus showed a distinct preference for Eucalyptus over both C4 species. Anisocentropus was observed to ingest C4 plant litter, particularly in the absence of other choices, and faecal material collected was clearly of C4 origin, as determined by stable isotope analysis. However, the stable carbon isotope values of the larvae did not shift away from their C3 signature in any of the feeding trials.5. These data suggest that shredders avoid the consumption of C4 plants, in favour of native C3 species that appear to be of lower food quality (based on C : N ratios). Lower rates of consumption and lack of assimilation of C4 carbon also suggest that shredders may have a limited ability to process this material, even in the absence of alternative litter sources. Large scale clearing of forest and vegetation for C4 crops such as sugarcane will undoubtedly have important consequences for stream ecosystem function.
Effect of packaging cycle on the colour stability of six beef muscles stored in a modified atmosphere mother pack system with oxygen scavengers
Authors: Isdell Emer , Allen Paul , Doherty Alice , Butler Francis 
Published: May 2003

SummaryThe effect of two packaging cycles (double flush, 28 s; triple flush, 55 s) on the colour stability of beef in retail trays with oxygen scavengers within a mother pack (50% CO2/50% N2) was assessed. Steaks from six muscles, M. longissimus dorsi, M. psoas major, M. semimembranosus, M. gluteus medius, M. semitendinosus and M. biceps femoris, were examined. The residual oxygen in mother packs was unaffected by the packaging cycle and was below 0.1% in trays for both treatments for up to 6 weeks storage. After storage for 2, 4 or 6 weeks, the packaging cycle had no effect on colour stability (HunterLab a and hue) during 96 h of display. Panel scores for visual and odour acceptability of packaged steaks were generally as high as for fresh controls. Based on reflectance measurements (R630 –R580), M. longissimus dorsi and M. semitendinosus steaks had a display life of 4 days after storage for up to 6 weeks. M. psoas major and M. semimembranosus steaks had a display life as long as fresh controls after 4 weeks, whereas M. gluteus medius and M. biceps femoris steaks had a shorter display life than fresh steaks. It was concluded that the double‐flush cycle could be used without affecting the colour or acceptability of beefsteaks.
Changes in carotenoid, physicochemical and sensory values of deep‐fried carrot chips during storage
Authors: Sulaeman Ahmad , Keeler Laurie , Giraud David W. , Taylor Steve L. , Driskell Judy A. 
Published: May 2003

SummaryDeep‐fried carrot chips were packaged in layered film (metallized polyester and linear low‐density polyethylene) pouches under a partial vacuum of <1% O2 concentration. Packages containing chips were stored in dark chambers at three conditions: 0–1 °C, 94–98% relative humidity (r.h.) (A); 22–23 °C, 31–45% r.h. (B); and 29–31 °C, 89–93% r.h. (C) for 0–5 months. Retention of α‐ and β‐carotene content and vitamin A activity were >82% over 5 months for all conditions. Colour values (L, a, b) were unchanged over 5 months for A and B, but decreased gradually (P < 0.05) for C. No changes in moisture content, fat content, water activity, texture values and sensory values were observed over time for A and B, but changed (P < 0.05) for C. No sensory differences were observed by condition or time in colour. Carrot chips, packaged in partially vacuumed opaque pouches, can be stored for at least 5 months at 0–1 °C, 94–98% r.h. or 22–23 °C, 31–45% r.h.
An analysis of water vapour diffusion in whey protein films
Authors: Yoshida Cristiana M. P. , Antunes Antonio C. B. , Antunes Leila J. , Antunes Aloísio J. 
Published: May 2003

SummaryThe macroscopic aspects of moisture transmission in whey protein films were determined by measuring water vapour adsorption. A theoretical model was constructed in which two kinds of water vapour fluxes were considered: one originating from diffusion, whilst the other was a flux due to the gravitation drift of moisture. The comparison of theoretical and experimental results showed that only the diffusion process was present.
Flavour components of orange wine made from a Turkish cv. Kozan
Authors: Selli Serkan , Cabaroglu Turgut , Canbas Ahmet 
Published: May 2003

SummaryVolatile flavour components of a wine made from orange variety Kozan were isolated by adsorption on Amberlite XAD‐2 resin followed by extraction with pentane–dichloromethane (2 : 1, v/v), identification by GC‐MS and quantification by GC‐FID using an internal standard method. In the Kozan wine, seventy‐five volatile components, including terpenes (twenty), alcohols (sixteen), esters (eighteen), volatile phenols (eleven), acids (five), ketones (two), aldehyde (one), lactone (one) and C13‐norisoprenoid (one) were identified. Isoamyl alcohol, 2‐phenylethanol, linalool, terpinene‐4‐ol and ethyl‐4‐hydroxy butanoate were the main components. Considering their threshold values and the concentrations they are present in, the most potent aroma compounds of the orange wine were ethyl hexanoate, ethyl octanoate, linalool, citronellol, 2‐phenylethanol and eugenol.
The kinetic evaluation of the use of high hydrostatic pressure to destroy Lactobacillus plantarum and Lactobacillus brevis
Authors: Mallidis C. , Galiatsatou P. , Taoukis P. S. , Tassou C. 
Published: May 2003

SummaryThe kinetics (D and zp values) of the high‐pressure destruction of Lactobacillus plantarum and Lactobacillus brevis, isolated from traditional Greek salads, were determined. These two strains exhibited the highest pressure resistance of all bacteria and yeasts isolated from these products. Model suspensions of phosphate buffer (pH 7.0) or citrate buffer (pH 4.2) were used for high‐pressure inactivation. The D values ranged from 11 to 1160 s in a neutral environment and a pressure range of 530–400 MPa, and from 1.5 to 560 s in an acidic environment with a pressure range of 530–270 MPa. A significant reduction in the pressure resistance was observed by lowering the pH of the suspension medium, especially as the pressure became greater. The effect of pressure change on D values was pH dependent. Values of zp of 70 and 80 MPa for L. plantarum and 71 and 100 MPa for L. brevis were obtained in neutral and acidic environments, respectively.
Ethics in food and agriculture: views from FAO‡
Authors: Bhardwaj Minakshi , Maekawa Fumi , Niimura Yuki , Macer Darryl R. J. 
Published: May 2003

SummaryThis paper presents analysis of interviews conducted at the United Nations Food and Agricultural Organization (FAO) during June to August 1999, which reveal the concerns behind the development of the Ethics in Food and Agriculture Program at FAO. Formal interviews with 103 staff members of all positions and across all divisions of FAO, revealed that although ethics as a word was not widely and openly discussed at FAO until the end of the 1990s, as indicated by the nature of the programmes and policies, the members had deep ethical motivation for their work. The results of the keyword analysis of the interviews are presented under the general issues of food, rural development, information, genetic modification, private sector and funding, environment, animal issues and personnel matters. Most of the interviewed staff saw ethics as the basis of the constitutional mandate, with the role of FAO being to promote global food security, balanced conservation, management and utilization of natural resources, and sustainable rural development. Information dissemination, and the need for a participatory approach were also raised as major issues by a third of the people interviewed.
Cryoprotection of protein by highly concentrated branched oligosaccharides
Authors: Auh J. H. , Kim Y. R. , Cornillon P. , Yoon J. , Yoo S. H. , Park K. H. 
Published: May 2003

SummaryCryoprotection of protein by highly concentrated branched oligosaccharides (HBOS) was investigated by using a model solution containing bovine serum albumin (BSA). The glass transition temperature of the BSA solution with HBOS, determined by modulated differential scanning calorimetry, was −16.1 °C, which is higher than that of sucrose at either 4 or 8% concentration by weight (−27.2 °C). Also, changes in the unfrozen water fraction and their mobilities, determined by nuclear magnetic resonance, were used as indices of protein stabilization. The results revealed that the amount of unfrozen water increased whereas the mobility was decreased by addition of HBOS. Thus we propose that the cryoprotection effect can occur by preserving the protein in a rigid structure formed by the water and the cryoprotectant HBOS.
Shelf‐life modelling of ready‐to‐eat coconut
Authors: Sinigaglia Milena , Corbo Maria R. , D'Amato Daniela , Campaniello Daniela , Altieri Clelia 
Published: May 2003

SummaryIn this research the possible use of coconut as raw material to produce ready‐to‐eat fruit was investigated. The development of spoilage micro‐organisms in packaged cut coconut stored at 4, 12, 21 and 24 °C was monitored. Spoilage of minimally processed coconut was correlated with high levels of mesophilic bacteria and was strongly dependent on temperature; however the modified atmosphere, created by respiration of the fruit when contained under a film barrier, could be fundamental to the determination of the product's shelf‐life. The shelf‐life of the product was kinetically modelled in order to check the effects of storage temperature and to assess the microbial indices most relevant for hygiene and quality of the product. Our results suggest that mathematical modelling could allow manufactures to rely on more objective parameters to determine the shelf‐life of their products.
The extension of the shelf‐life of sardine which were packaged in a vacuum stored under refrigeration, and treated by δ‐irradiation
Authors: Kasımoğlu Aylin , Denli Emine , İç Erhan 
Published: May 2003

SummarySardines (Sardina pichardus) were vacuum packaged in polyethylene bags, and irradiated at 1, 2 and 3 kGy doses in a Co‐60 δ‐irradiator. The unirradiated and irradiated samples were stored at 2 ± 1 °C. Microbiological analyses were done for total aerobic mesophiles, micrococci and staphylococci, coagulase positive staphylococci,Enterobacteriaceae, coliform bacteria,Escherichia coli, and psychrophilic bacteria. Trimethylamine‐nitrogen (TMA‐N), thiobarbituric acid (TBA) and pH values were determined. Sensory attributes were also evaluated. In the unirradiated samples, TMA‐N and pH values showed good correlations with sensory scores. There were no differences in TBA values between the irradiated samples. Based on microbiological criteria, the shelf‐life increased two to threefold compared with the control samples. These experiments demonstrate that irradiation extends the storage life of pre‐packaged sardines and that, for practical purposes, the different treatments make very little difference to the extension of shelf‐life of acceptable product.
Evaluation of nutrients and some anti‐nutrients in lesser‐known, underutilized oilseeds
Authors: Enujiugha Victor N. , Ayodele‐Oni Olubunmi 
Published: May 2003

SummaryThe levels of anti‐nutritional factors and the chemical composition of five underutilized and not well known commercial oilseeds – castor bean, conophor nut, ‘egusi’ melon, African oil bean and locust bean – were determined. The crude protein values for the respective oilseeds were 201.8, 227.5, 314.1, 206.3 and 290.6 g kg−1 DM, whereas the crude fat values were 449.6, 491.8, 439.3, 522.8 and 261.9 g kg−1 DM respectively. The results show that oilseeds may be a good source of vegetable oils, whereas defatted cakes might be useful in food fortification or as animal feed ingredients. The crude fibre contents of oilseeds were found to be significant (31.4–90.6 g kg−1 DM), which suggests that consumption of oilseeds and their products would aid bowel functioning.The seeds were found to contain high concentrations of phosphorus and potassium (2.6–4.6 and 3.9–6.5 g kg−1 DM, respectively); the low sodium content observed is in agreement with the generally low sodium encountered in unprocessed foods. The energy values of the seeds range from 4.1 Mcal kg−1 DM in locust bean to 5.9 Mcal kg−1 DM in conophor nut, which could be considered adequate for supplying useful amounts of calories.Oxalates, phytates and tannins occurred in varying concentrations in the oilseeds. Whereas castor bean contained the highest level of oxalates (6.5 g kg−1 DM), the same seed was relatively low in its content of the other anti‐nutritional factors analysed. Phytic acid, phytate phosphorus and tannins had their highest values in African oil bean seed (4.1, 1.2 and 0.8 g kg−1 DM, respectively), which may be considered a major barrier to the use of the seed. However, it is expected that traditional methods employed in processing the seeds, namely hydrothermal treatment, soaking and fermentation, would considerably reduce the levels of the anti‐nutritional factors.
Effects of extrusion conditions on quality of cassava bran/cassava starch extrudates
Authors: Hashimoto Jorge Minoru , Grossmann Maria Victoria E. 
Published: May 2003

SummaryBlends of cassava bran and cassava starch were processed in a single‐screw extruder. Response surface methodology was used to determine the effect of the concentration of cassava bran (10–50%), barrel temperature (150–210 °C), feed moisture (16–20%) and screw speed (120–180 r.p.m.) on the characteristics of the dried extrudates. All the independent variables were significant (P < 0.05) for radial expansion. The water absorption index (WAI) and water solubility index (WSI) were affected by bran level, screw speed and temperature, while only moisture and temperature influenced specific volume. The maximum radial expansion was found when all the independent variables were at their lowest levels. Lowest‐density extrudates (highest specific volume) were obtained at 16–18% moisture and 180–200 °C. An increase in bran level increased the WAI but decreased the WSI when the temperature was higher than 170 °C . Screw speed had a slight effect on those responses, decreasing water absorption and increasing water solubility when changed from 120 to 180 r.p.m.
Root competition can cause a decline in diversity with increased productivity
Authors: Rajaniemi Tara K. , Allison Victoria J. , Goldberg Deborah E. 
Published: May 2003

Summary 1 Plant community theory often invokes competition to explain why species diversity declines as productivity increases. Competition for all resources might become more intense and lead to greater competitive exclusion or, alternatively, competition for light only could become more intense and exclude poor light competitors. 2 To test these hypotheses, we constructed communities of seven old‐field species using combined monocultures. Constructs experienced no interspecific competition, only shoot competition or only root competition, with and without fertilizer. Diversity in these limited interaction communities was compared to diversity in unfertilized and fertilized mixtures of the seven species. 3 Diversity decreased with fertilization in mixtures and in communities with only root competition. Shoot competition had small effects on the community and did not contribute to changes in diversity with fertilization. 4 Root competition may strongly impact plant community structure in unproductive communities where light never becomes limiting, or under non‐equilibrium conditions following human disturbances.