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Little Effect (little + effect)
Kinds of Little Effect Selected AbstractsReduced-impact Logging has Little Effect on Temporal Activity of Frugivorous Bats (Chiroptera) in Lowland AmazoniaBIOTROPICA, Issue 3 2009Steven J. Presley ABSTRACT Reduced-impact logging (RIL) represents a viable option for sustainable use of Neotropical lowland forests while minimizing negative effects on local biodiversity. Many Neotropical bats of the family Phyllostomidae provide ecosystem services associated with pollination and seed dispersal that promote the regeneration of disturbed areas; therefore, effects of RIL on these species is of particular concern. We determined patterns of temporal activity, degree of temporal overlap of activity, and dispersion in peaks of activity for seven abundant species of frugivorous bat in Tapajós National Forest, Pará, Brazil. In addition, we evaluated the effects of RIL at a harvest level of 18.7 m3/ha and habitat physiognomy on temporal patterns of activity for these species. Bats were surveyed for four nights at each of 96 sites for a total sampling effort of 64,512 net-m-h. Sites were distributed among four experimental blocks, two blocks of unlogged forest and two blocks of forest subjected to RIL. Half of the sites in each management type were in forest gaps and half were in closed-canopy forest. In general, species exhibited similar patterns of activity, and greater than expected temporal overlap in activity among species. RIL and forest physiognomy had little effect on activity patterns of species. RIL in Amazonia removes fewer trees than do naturally occurring treefalls and such changes in habitat structure do not alter activity patterns of frugivorous bats. Evidence suggests that RIL does not have an appreciable adverse effect on frugivorous bats in Amazonia. RESUMO A exploração madeireira de impacto reduzido é uma opção viável para o uso sustentável de florestas de planícies tropicais, ao passo em que também minimizam os efeitos sobre a biodiversidade local e processos ecossistêmicos. Avaliações dos efeitos de regimes de derrubada de árvores geralmente se baseiam em respostas em nível populacional ou de comunidades e ignoram respostas comportamentais que podem ter consequências críticas em processos ecossistêmicos locais. Muitos dos morcegos neotropicais filostomídeos proporcionam serviços ecossistêmicos associados à polinização e dispersão de sementes, que promovem regeneração de áreas degradadas. Por esse motivo, os efeitos da exploração madeireira de impacto reduzido, sobre essas espécies, devem ter sua importância considerada. Nós avaliamos padrões temporais de atividade, grau de sobreposição temporal de atividade, e dispersão nos picos de atividade de sete espécies de morcegos frugívoros abundantes na Floresta Nacional de Tapajós, Pará, Brasil. Além disso, avaliamos os efeitos da exploração madeireira de impacto reduzido e da fisionomia de habitat (lacunas florestais e locais de dossel fechado) nos padrões temporais de atividade desses morcegos. Em geral, as espécies exibiram padrões de atividade similares, o que resulta em uma sobreposição temporal maior do que a esperada na atividade das espécies. A exploração madeireira de impacto reduzido e a fisionomia florestal tiveram pouco efeito nos padrões de atividades das espécies observadas. A exploração madeireira ora apresentada (2-4 árvores/ha) se propõe a um impacto menor que o associado às quedas naturais de árvores na Amazônia e aparenta não alterar a estrututra dos habitats de forma significativa à atividade das espécies de morcegos aqui estudadas. Consequentemente, não há evidências para acreditar que a exploração madeireira impacto reduzido possua efeitos adversos em espécies abundantes de morcegos frugívoros na Amazônia ou em suas capacidades de continuar a promover a regeneração de áreas degradadas via polinização ou dispersão de sementes. [source] Androgen replacement therapy improves function in male rat muscles independently of hypertrophy and activation of the Akt/mTOR pathwayACTA PHYSIOLOGICA, Issue 4 2009C. Hourdé Abstract Aim:, We analysed the effect of physiological doses of androgens following orchidectomy on skeletal muscle and bone of male rats, as well as the relationships between muscle performance, hypertrophy and the Akt/mammalian target of rapamycin (mTOR) signalling pathway involved in the control of anabolic and catabolic muscle metabolism. Methods:, We studied the soleus muscle and tibia from intact rats (SHAM), orchidectomized rats treated for 3 months with vehicle (ORX), nandrolone decanoate (NAN) or dihydrotestosterone (DHT). Results:, Orchidectomy had very little effect on the soleus muscle. However, maximal force production by soleus muscle (+69%) and fatigue resistance (+35%) in NAN rats were both increased when compared with ORX rats. In contrast, DHT treatment did not improve muscle function. The relative number of muscle fibres expressing slow myosin heavy chain and citrate synthase activity were not different in NAN and ORX rats. Moreover, NAN and DHT treatments did not modify muscle weights and cross-sectional area of muscle fibres. Furthermore, phosphorylation levels of downstream targets of the Akt/mTOR signalling pathway, Akt, ribosomal protein S6 and eukaryotic initiation factor 4E-binding protein 1 were similar in muscles of NAN, DHT and ORX rats. In addition, trabecular tibia from NAN and DHT rats displayed higher bone mineral density and bone volume when compared with ORX rats. Only in NAN rats was this associated with increased bone resistance to fracture. Conclusion:, Physiological doses of androgens are beneficial to muscle performance in orchidectomized rats without relationship to muscle and fibre hypertrophy and activation of the Akt/mTOR signalling pathway. Taken together our data clearly indicate that the activity of androgens on muscle and bone could participate in the global improvement of musculoskeletal status in the context of androgen deprivation induced by ageing. [source] The impact of after-school programs on the routine activities of middle-school students: Results from a randomized, controlled trial,CRIMINOLOGY AND PUBLIC POLICY, Issue 2 2009Amanda Brown Cross Research Summary Unsupervised after-school time for adolescents is a concern for parents and policymakers alike. Evidence linking unsupervised adolescent socializing to problem behavior outcomes heightens this concern among criminologists. Routine activities theory suggests that, when youth peer groups congregate away from adult authority, both opportunity for and motivation to engage in deviant acts increase. After-school programs are a possible solution to unsupervised teen socializing during afternoon hours and are much in demand. However, empirical research has yet to test the relationship between the availability of after-school programs and youth routine activities. This study presents evidence from a multisite, randomized, controlled trial of an after-school program for middle-school students in an urban school district. Policy Implications Youth in the treatment group engaged in less unsupervised socializing after school than youth in the control group but not as much less as would be expected if the after-school program was providing consistent supervision to youth who would otherwise be unsupervised. Additional analyses examined why the influence of the after-school program was not more pronounced. We found that, although program attendance was related to decreases in unsupervised socializing, the program did not attract many delinquency-prone youths who were unsupervised, which suggests that the students most in need of the program did not benefit. Furthermore, data obtained from a mid-year activity survey revealed that youth in the study were highly engaged in a variety of after-school activities. The addition of the after-school program into the mixture of available activities had little effect on the frequency with which students participated in organized activities after school. [source] The , isotypes of tubulin in neuronal differentiation,CYTOSKELETON, Issue 7 2010Jiayan Guo Abstract The differences among the vertebrate , isotypes of tubulin are highly conserved in evolution, suggesting that they have functional significance. To address this, we have used differentiating neuroblastoma cells as a model system. These cells express the ,I, ,II, and ,III isotypes. Although there is no difference prior to differentiation, a striking difference is seen after differentiation. Both ,I and ,III occur in cell bodies and neurites, while ,II occurs mostly in neurites. Knocking down ,I causes a large decrease in cell viability while silencing ,II and ,III does not. Knocking down ,II causes a large decrease in neurite outgrowth without affecting viability. Knocking down ,III has little effect on neurite outgrowth and only decreases viability if cells are treated with glutamate and glycine, a combination known to generate free radicals and reactive oxygen species. It appears, therefore, that ,I is required for cell viability, ,II for neurite outgrowth and ,III for protection against free radicals and reactive oxygen species. © 2010 Wiley-Liss, Inc. [source] Role of myosin II activity and the regulation of myosin light chain phosphorylation in astrocytomasCYTOSKELETON, Issue 1 2008Bodour Salhia Abstract The generation of contractile force mediated by actin-myosin interactions is essential for cell motility. Myosin activity is promoted by phosphorylation of myosin light chain (MLC). MLC phosphorylation in large part is controlled by kinases that are effectors of Rho family GTPases. Accordingly, in this study we examined the effects of ROCK and Rac1 inhibition on MLC phosphorylation in astrocytoma cells. We found that low concentrations of the ROCK inhibitor Y27632 increased the phosphorylation state of the Triton X-100 soluble fraction of MLC, whereas higher concentrations of Y27632 decreased soluble phospho-MLC. These effects of Y27632 were dependent on Rac1. The soluble form of phospho-MLC comprises about 10% of total phospho-MLC in control cells. Interestingly, ROCK inhibition led to a decrease in the phosphorylation state of total MLC, whereas Rac1 inhibition had little effect. Thus, the soluble form of MLC is differentially regulated by ROCK and Rac1 compared with MLC examined in a total cell extract. We also observed that astrocytoma migration is stimulated by low concentrations of the myosin II inhibitor blebbistatin. However, higher concentrations of blebbistatin inhibit migration leading us to believe that migration has a biphasic dependence on myosin II activity. Taken together, our data show that modulation of myosin II activity is important in determining optimal astrocytoma migration. In addition, these findings suggest that there are at least two populations of MLC that are differentially regulated. Cell Motil. Cytoskeleton 2008. © 2007 Wiley-Liss, Inc. [source] Use of mouthguards by basketball players in Victoria, AustraliaDENTAL TRAUMATOLOGY, Issue 4 2003Helen Cornwell Abstract ,,,Basketball is a popular sport in Australia. Although orofacial injuries are common, mouthguard (MG) wear in basketball appears to be low. The purposes of this study were: to measure mouthguard wear by basketball players before and after a promotional intervention; to assess players' knowledge of the value of mouthguards for prevention of injury; and to describe their experience of orofacial injury. Two questionnaires (baseline and follow-up) were administered to a convenience sample of 496 basketball players in Victoria, Australia. Players recruited were youths (12,15-year olds, n = 208) and adults (18 years and over, n = 288), from all basketball levels (social to elite). Completion of the baseline questionnaire was followed immediately by an intervention comprising written and verbal information, a mouthguard blank and instructions on mouthguard construction. The follow-up questionnaire was mailed to all respondents 10,12 weeks later; 135 youths (65%) and 157 adults (54%) completed this. Mouthguard wear at baseline was low but was more frequent at games (62%) than at training (25%). Despite 90% of players acknowledging the protective value of a mouthguard, wear by youths did not increase following the intervention, and wear by adults increased by only 14% for training and 10% at games. Previous orofacial injury was recorded at baseline by 23% of players, but few had requested compensation from Basketball Australia (youths, 17%; adults, 30%). Two predictor variables were statistically identified as related to mouthguard wear: previous orofacial injury and age group. Mouthguard wear was significantly more frequent amongst players with previous injury; such players were 2.76 times more likely to be wearers than those without previous injury. Youths were 2.31 times more likely to wear mouthguards than adults. Only 34 players (12% of respondents at follow-up) had a mouthguard constructed from the blank provided. Although youth and adult groups differed, the overall extent of mouthguard use was disappointingly low. Despite wide recognition of mouthguard value, the intervention had little effect on promoting their use. [source] Patient Injuries from Surgical Procedures Performed in Medical Offices: Three Years of Florida DataDERMATOLOGIC SURGERY, Issue 12p1 2004Brett Coldiron MD, FACP Background. Many state medical boards and legislatures are in the process of developing regulations that restrict procedures in the office setting with the intention of enhancing patient safety. The highest quality data in existence on office procedure adverse incidents have been collected by the state of Florida. Objective. The objective was to determine and analyze the nature of surgical incidents in office-based settings using 3 years of Florida data from March 2000 to March 2003. Methods. An incidence study with prospective data collection was performed. Individual reports that resulted in death or a hospital transfer were further investigated by determining the reporting physician's board certification status, hospital privilege status (excluding procedure specific operating room privileges), and office accreditation status. Results. In 3 years there were 13 procedure-related deaths and 43 procedure-related complications that resulted in a hospital transfer. Seven of the 13 deaths involved elective cosmetic procedures, 5 of which were performed under general anesthesia and 2 of which were performed with intravenous sedation anesthesia. Forty-two percent of the offices reporting deaths and 50% of the offices reporting procedural incidents that resulted in a hospital transfer were accredited by an independent accreditation agency. Ninety-six percent of physicians reporting surgical incidents were board-certified, and all had hospital privileges. Conclusions. Restrictions on office procedures for medically necessary procedures, such as requiring office accreditation, board certification, and hospital privileges, would have little effect on overall safety of surgical procedures. These data also show that the greatest danger to patients lies not with surgical procedures in office-based settings per se, but with cosmetic procedures that are performed in office-based settings, particularly when under general anesthesia. Our conclusions are dramatically different from those of a recent study, which claimed a 12-fold increased risk of death for procedures in the office setting. [source] Emx3 is required for the differentiation of dorsal telencephalic neuronsDEVELOPMENTAL DYNAMICS, Issue 8 2009Gudrun Viktorin Abstract emx3 is first expressed in prospective telencephalic cells at the anterior border of the zebrafish neural plate. Knockdown of Emx3 function by morpholino reduces the expression of markers specific to dorsal telencephalon, and impairs axon tract formation. Rescue of both early and late markers requires low-level expression of emx3 at the one- or two-somite stage. Higher emx3 expression levels cause dorsal telencephalic markers to expand ventrally, which points to a possible role of emx3 in specifying dorsal telencephalon and a potential new function for Wnt/beta-catenin pathway activation. In contrast to mice, where Emx2 plays a major role in dorsal telencephalic development, knockdown of zebrafish Emx2 apparently does not affect telencephalic development. Similarly, Emx1 knockdown has little effect. Previously, emx3 was thought to be fish-specific. However, we found all three emx orthologs in Xenopus tropicalis and opossum (Monodelphis domestica) genomes, indicating that emx3 was present in an ancestral tetrapod genome. Developmental Dynamics 238:1984,1998, 2009. © 2009 Wiley-Liss, Inc. [source] Differential roles of two major brain structures, mushroom bodies and central complex, for Drosophila male courtship behaviorDEVELOPMENTAL NEUROBIOLOGY, Issue 8 2006Takaomi Sakai Abstract Drosophila male courtship is a complex and robust behavior, the potential for which is genetically built into specific neural circuits in the central nervous system. Previous studies using male-female mosaics and the flies with defects in particular brain structures implicated the critical central regions involved in male courtship behavior. However, their acute physiological roles in courtship regulation still largely remain unknown. Using the temperature-sensitive Dynamin mutation, shibirets1, here we demonstrate the significance of two major brain structures, the mushroom bodies and the central complex, in experience-independent aspects of male courtship. We show that blocking of synaptic transmission in the mushroom body intrinsic neurons significantly delays courtship initiation and reduces the courtship activity by shortening the courtship bout length when virgin females are used as a sexual target. Interestingly, however, the same treatment affects neither initiation nor maintenance of courtship toward young males that release courtship-stimulating pheromones different from those of virgin females. In contrast, blocking of synaptic transmission in a central complex substructure, the fan-shaped body, slightly but significantly reduces courtship activity toward both virgin females and young males with little effect on courtship initiation. Taken together, our results indicate that the neuronal activity in the mushroom bodies plays an important role in responding to female-specific sex pheromones that stimulate initiation and maintenance of male courtship behavior, whereas the fan-shaped body neurons are involved in maintenance of male courtship regardless of the nature of courtship-stimulating cues. © 2006 Wiley Periodicals, Inc. J Neurobiol, 2006 [source] Drug education: myth and realityDRUG AND ALCOHOL REVIEW, Issue 1 2001GRAEME HAWTHORNE Abstract Recently there has been an increase in Australian public funds for drug education. The accompanying rhetoric asserts that it is to enable abstinence among young people. This contradicts some State Government education guidelines endorsing harm minimization. A literature search of the key electronic databases, drug agency libraries, the Internet and reference lists identified evaluation research in school-based drug education. There is little evidence to support the new public rhetoric. The predictors of adolescent drug use are social and personal; schools can have little effect on these. Four models of drug education are described. Schools, however, mix-and-match activities from different models, and exposure is too slight for major effects on behaviours. Although methodological difficulties affect findings, none of the drug education models show consistent behavioural effects over time. There is a mismatch between the new public rhetoric and the evaluation research literature. Reasons for this are explored, including that there are two stakeholder groups, one with exaggerated ideological anti-drug messages and the other with more realistic perspectives about what schools can reasonably achieve. The paradox is that the rhetoric is needed for continued funding, yet this same rhetoric sets up criteria which doom drug education to failure. [source] LBY135, a novel anti-DR5 agonistic antibody induces tumor cell,specific cytotoxic activity in human colon tumor cell lines and xenografts,DRUG DEVELOPMENT RESEARCH, Issue 2 2008Jing Li Abstract TRAIL (TNF-related apoptosis-inducing ligand) induces apoptosis on binding to DR4 and DR5 receptors on the surface of tumor cells. These receptors are of particular interest in the development of cancer therapeutics as they preferentially mediate tumor cell apoptosis. We have generated a chimeric anti-DR5 agonistic antibody, LBY135, from its murine parental antibody, LCR211, identified using hybridoma technology. Both LCR211 and LBY135 specifically bind to DR5 with nanomolar affinity, mimic TRAIL to induce cell death in tumor cells, and have little effect on non-transformed cells in vitro. The anti-DR5 antibody reduced viability in 45% of a panel of 40 human colon cancer cell lines with IC50 values of 20,nM or less. In vivo, using human colorectal tumor xenograft mouse models, LCR211 induced tumor regression and showed enhanced efficacy when combined with 5-FU. Both in vitro evaluation of ADCC (antibody-dependent cell-mediated cytotoxicity) and CDC (complement-dependent cytotoxicity), and in vivo studies using a non-functional DR5 specific antibody or SCID-Beige mice, suggested ADCC and CDC are unlikely to be the mechanism to ablate tumors in vivo. LBY135 and LCR211 appear to mediate cell death and tumor regression mainly through apoptosis, as demonstrated by the activation of caspase 3, caspase 8, M30, and TUNEL assay. In addition, the discovery of synergy between cross-linked LBY135 and TRAIL not only revealed the unique epitope of LBY135, but also demonstrated an additional mechanism of action for LBY135 in vivo. LBY135 demonstrates promise as a novel therapeutic for cancer treatment and is currently in Phase I clinical trials. Drug Dev Res 69: 69,82, 2008. © 2008 Wiley-Liss, Inc. [source] The impact of prolonged fasting during aestivation on the structure of the small intestine in the green-striped burrowing frog, Cyclorana alboguttataACTA ZOOLOGICA, Issue 1 2005Rebecca L. Cramp Abstract The effects of short-term fasting and prolonged fasting during aestivation on the morphology of the proximal small intestine and associated organs were investigated in the green-striped burrowing frog, Cyclorana alboguttata (Anura: Hylidae). Animals were fasted for 1 week while active or for 3,9 months during aestivation. Short-duration fasting (1 week) had little effect on the morphology of the small intestine, whilst prolonged fasting during aestivation induced marked enteropathy including reductions in intestinal mass, length and diameter, longitudinal fold height and tunica muscularis thickness. Enterocyte morphology was also affected markedly by prolonged fasting: enterocyte cross-sectional area and microvillous height were reduced during aestivation, intercellular spaces were visibly reduced and the prevalence of lymphocytes amongst enterocytes was increased. Mitochondria and nuclei were also affected by 9 months of aestivation with major disruptions to mitochondrial cristae and increased clumping of nuclear material and increased infolding of the nuclear envelope. The present study demonstrates that the intestine of an aestivating frog responds to prolonged food deprivation during aestivation by reducing in size, presumably to reduce the energy expenditure of the organ. [source] Computational fluid dynamics modelling of boundary roughness in gravel-bed rivers: an investigation of the effects of random variability in bed elevationEARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2001A.P. Nicholas Abstract Results from a series of numerical simulations of two-dimensional open-channel flow, conducted using the computational fluid dynamics (CFD) code FLUENT, are compared with data quantifying the mean and turbulent characteristics of open-channel flow over two contrasting gravel beds. Boundary roughness effects are represented using both the conventional wall function approach and a random elevation model that simulates the effects of supra-grid-scale roughness elements (e.g. particle clusters and small bedforms). Results obtained using the random elevation model are characterized by a peak in turbulent kinetic energy located well above the bed (typically at y/h,=,0·1,0·3). This is consistent with the field data and in contrast to the results obtained using the wall function approach for which maximum turbulent kinetic energy levels occur at the bed. Use of the random elevation model to represent supra-grid-scale roughness also allows a reduction in the height of the near-bed mesh cell and therefore offers some potential to overcome problems experienced by the wall function approach in flows characterized by high relative roughness. Despite these benefits, the results of simulations conducted using the random elevation model are sensitive to the horizontal and vertical mesh resolution. Increasing the horizontal mesh resolution results in an increase in the near-bed velocity gradient and turbulent kinetic energy, effectively roughening the bed. Varying the vertical resolution of the mesh has little effect on simulated mean velocity profiles, but results in substantial changes to the shape of the turbulent kinetic energy profile. These findings have significant implications for the application of CFD within natural gravel-bed channels, particularly with regard to issues of topographic data collection, roughness parameterization and the derivation of mesh-independent solutions. Copyright © 2001 John Wiley & Sons, Ltd. [source] Post-fire recovery of ant communities in Submediterranean Pinus nigra forestsECOGRAPHY, Issue 2 2006Anselm Rodrigo This study analyzes the variations in the structure and composition of ant communities in burned Pinus nigra forests in central Catalonia (NE Spain). Pinus nigra forests do not recover after fire, changing to shrublands and oak coppices. For this reason, we suggest that ant communities of burned P. nigra forests will change after fire, because the post-fire scenario, in particular with the increase of open areas, is different to the unburned one, and more favourable for some species than for others. In four locations previously occupied by P. nigra forests where different fires occurred 1, 5, 13 and 19 yr before the sampling, we sampled the structure and composition of ant communities with pitfall traps, tree traps and net sweeping in unburned plots and in plots affected by canopy and understory fire. The results obtained suggest that canopy and understory fire had little effect on the structure of ant communities. Thus, many variables concerning ant communities were not modified either by fire type (understory or canopy fire) or by time since fire. However, a number of particular species were affected, either positively or negatively, by canopy fire: three species characteristic of forest habitats decreased after fire, while eight species characteristic of open habitats increased in areas affected by canopy fire, especially in the first few years after fire. These differences in ant community composition between burned and unburned plots imply that the maximum richness is achieved when there is a mixture of unburned forests and areas burned with canopy fire. Moreover, as canopy cover in P. nigra forests burned with canopy fire is not completed in the period of time studied, the presence of the species that are characteristic of burned areas remains along the chronosequence studied, while the species that disappear after fire do not recover in the period of time considered. Overall, the results obtained indicate that there is a persistent replacement of ant species in burned P. nigra forests, as is also the case with vegetation. [source] The effects of the invasive Argentine ant (Linepithema humile) and the native ant Prenolepis imparis on the structure of insect herbivore communities on willow trees (Salix lasiolepis)ECOLOGICAL ENTOMOLOGY, Issue 6 2008JULIE P. NYGARD Abstract 1.,We examined the relative effects of the invasive Argentine ant, Linepithema humile, and a common native ant, Prenolepis imparis, on the community of herbivorous insects occurring on willow trees, Salix lasiolepis in Northern California, U.S.A. 2.,Using paired control and treatment branches from which we excluded ants and other non-volant predators, we found that effects of Argentine ants on the herbivore community were generally similar to those of P. imparis. Argentine ants and P. imparis suppressed the damage by skeletonising insects by 50%, but had little effect on most other external-feeding or internal-feeding guilds. 3.,The abundance of aphids was 100% greater in the presence of Argentine ants, but there was no effect on aphid numbers in the presence of P. imparis. Late season aphid numbers were substantially higher in the presence of Argentine ants, but not P. imparis. 4.,The effects of Argentine ants on skeletonising insects and aphids combined with the overwhelming abundance of Argentine ant workers, suggests that they may have substantial, but often overlooked, effects on the herbivore communities on other plant species in or near riparian habitats in which they invade. [source] Effects of insects on primary production in temperate herbaceous communities: a meta-analysisECOLOGICAL ENTOMOLOGY, Issue 5 2003Malcolm D. Coupe Abstract., 1. The effects of insects on primary production in temperate herbaceous communities were investigated in a meta-analysis. The following hypotheses were tested: (1) the effect of insects on primary production depends on community type, (2) the effect of insects on primary production varies as a function of productivity, (3) insects have a greater effect on primary production in communities with low species diversity, and (4) insects have a larger effect on primary production during outbreaks. 2. Data were collected from 24 studies in which insecticides were used to suppress insects in self-sown or pastoral communities. Effect sizes were calculated from sprayed and control plot standing crop or yield, expressed as the log response ratio, ln (sprayed plot phytomass/control plot phytomass). 3. There was a significant increase in primary production as a result of insect suppression. Forb-dominated communities showed a more variable response than graminoid communities. During outbreaks, insects had a greater negative impact on primary production. Effect size was unaffected by productivity or plant species richness. 4. Although insects lower primary production in a diversity of temperate herbaceous communities, the basic measures by which such communities are often described have little effect on the proportional impact that insects have on primary production. While outbreaks are significant predictors of higher negative impact on primary production, causes of outbreaks are not always related to traits of the plant community. [source] Influence of hatch duration and individual daily growth rates on size structure of age-0 smallmouth bass cohorts in two glacial lakesECOLOGY OF FRESHWATER FISH, Issue 3 2008Q. E. Phelps Abstract,,, We assessed hatch dates and daily growth rates of age-0 smallmouth bass from two glacial lakes over a 3-year period. Hatching durations (19,27 days among years) of smallmouth bass occurred from late May until late June. Mean daily growth rate of age-0 smallmouth bass ranged from 0.56 to 1.56 mm·day,1. Correlation analysis indicated that hatch date had little effect on daily growth rates. Hatch date was significant in explaining variation in total length (TL) of age-0 smallmouth bass at time of capture in only three of six cases and hatch date never explained >50% of the variation in bass length. Daily growth rate significantly explained variation in smallmouth bass TL at time of capture in all six models, accounting for 31,86% of the variability in bass length. Our findings suggest that size structure of age-0 cohorts in some populations may be more strongly regulated by variation in individual daily growth rate than by hatch timing. [source] Ontogenetic diet profiles and size-dependent diet partitioning of ruffe Gymnocephalus cernuus, perch Perca fluviatilis and pumpkinseed Lepomis gibbosus in Lake BalatonECOLOGY OF FRESHWATER FISH, Issue 3 2006E. Rezsu Abstract ,, Life-long diet ontogeny and size-dependent intra- and interspecific diet partitioning of the native ruffe and perch and the introduced pumpkinseed, were studied in Lake Balaton. Estimated intraspecific diet overlap was high in ruffe, whereas in perch and pumpkinseed only the neighbouring size groups exhibited a high diet similarity. Interspecific diet overlap among size groups of the three species was moderate and ,60% diet overlap occurred only in 13 size group pair variations out of the 429 analysed. The earliest developmental stages of the three species were planktivorous, whereas larger ruffe and some size groups of perch and pumpkinseed fed dominantly on chironomids. Adult perch and pumpkinseed consumed different littoral macroinvertebrates, while the largest perch were piscivorous. Although productivities of the two studied areas differ significantly, this had only little effect on the diet ontogeny and diet partitioning of the three species. Present results suggest that in Lake Balaton these three species effectively partition food resources throughout their life span. [source] Affirmative Action in Higher Education: How Do Admission and Financial Aid Rules Affect Future Earnings?ECONOMETRICA, Issue 5 2005Peter Arcidiacono This paper addresses how changing the admission and financial aid rules at colleges affects future earnings. I estimate a structural model of the following decisions by individuals: where to submit applications, which school to attend, and what field to study. The model also includes decisions by schools as to which students to accept and how much financial aid to offer. Simulating how black educational choices would change were they to face the white admission and aid rules shows that race-based advantages had little effect on earnings. However, removing race-based advantages does affect black educational outcomes. In particular, removing advantages in admissions substantially decreases the number of black students at top-tier schools, while removing advantages in financial aid causes a decrease in the number of blacks who attend college. [source] MALE MARITAL WAGE DIFFERENTIALS: TRAINING, PERSONAL CHARACTERISTICS, AND FIXED EFFECTSECONOMIC INQUIRY, Issue 3 2010WILLIAM M. RODGERS III Using the National Longitudinal Survey of Youth 1979, we replicate previous estimates of the marital wage differential for white men, extend the analysis to African American men, then explain the within and between race differentials. We first control for formal job training, then for cognitive skills, parental background, and self-esteem with little effect. By contrast, the white differential but not the black differential disappears in fixed-effects estimation. We reconcile the cross-section/panel differentials by focusing on the distinct identification conditions employed by each technique. Men who never change marital status play a significant role in white cross-sectional estimates. (JEL J31, J12) [source] Delocation and European integration: is structural spending justified?ECONOMIC POLICY, Issue 35 2002Karen Helene Midelfart-Knarvik SUMMARY How is European integration changing the location of industry? And what part are national and EU aids to industry playing in this process? We show that states and regions are becoming more specialized within the EU, but this process is very slow. While there is no evidence of polarization occurring at the national level, some regions are losing out. National state aids to industry appear to have little effect for either good or ill, since their effectiveness at attracting economic activity and employment is limited. European Structural Funds expenditure, by contrast, does have an effect on the location of industry, notably by attracting industries that are intensive in research and development. However, this effect has mostly been acting counter to states' comparative advantage , R&D-intensive industries have been encouraged by these aids to locate in countries and regions that have low endowments of skilled labour. Only in Ireland, where Structural Funds reinforced rather than offset comparative advantage, have poor regions been enabled systematically to catch up with the EU average. [source] Online support for smoking cessation: a systematic review of the literatureADDICTION, Issue 11 2009Lion Shahab ABSTRACT Aim To examine the efficacy and acceptability of online, interactive interventions for smoking cessation and to identify treatment effect moderators and mediators. Methods A systematic review and meta-analysis of the literature (1990,2008) was conducted, finding 11 relevant randomized controlled trials. Data were extracted and risk ratios and risk differences estimated with a random effects model. Results There was no evidence of publication bias. Included trials were of variable methodological quality. Web-based, tailored, interactive smoking cessation interventions were effective compared with untailored booklet or e-mail interventions [rate ratio (RR) 1.8; 95% confidence interval (CI) 1.4,2.3] increasing 6-month abstinence by 17% (95% CI 12,21%). No overall effect of interactive compared with static web-based interventions was detected but there was significant heterogeneity, with one study obtaining a clear effect and another failing to find one. Few moderating or mediating factors were evaluated in studies and those that were had little effect. Pooled results suggest that only interventions aimed at smokers motivated to quit were effective (RR 1.3, 95% CI 1.0,1.7). Fully automated interventions increased smoking cessation rates (RR 1.4, 95% CI 1.0,2.0), but evidence was less clear-cut for non-automated interventions. Overall, the web-based interventions evaluated were considered to be acceptable and user satisfaction was generally high. Conclusion Interactive, web-based interventions for smoking cessation can be effective in aiding cessation. More research is needed to evaluate the relative efficacy of interactive web-based interventions compared with static websites. [source] Use of episcopic differential interference contrast microscopy to identify bacterial biofilms on salad leaves and track colonization by Salmonella ThompsonENVIRONMENTAL MICROBIOLOGY, Issue 4 2008J. C. Warner Summary Zoonotic pathogens such as Salmonella can cause gastrointestinal illness if they are ingested with food. Foods such as salads pose a greater risk because they are consumed raw and have been the source of major outbreaks of disease from fresh produce. The novel light microscopy methods used in this study allow detailed, high resolution imaging of the leaf surface environment (the phyllosphere) and allow pathogen tracking. Episcopic differential interference contrast microscopy coupled with epifluorescence was used to view the natural microflora in situ on salad leaves and their topographical distribution. Fluorescent nucleic acid staining was used to differentiate between bacterial colonists and inorganic debris. Salmonella enterica serovar Thompson expressing green fluorescent protein was inoculated onto individual spinach leaves for 24 h at 22°C in order to observe spatial and temporal patterning of colonization on the two surfaces of each leaf under different osmotic conditions. The results obtained show that salad leaves are host to high numbers of bacteria, typically 105 per square millimetre. Cells are present in complex three-dimensional aggregations which often have a slimy appearance, suggesting the presence of biofilms. Washing of the leaves had little effect on the number of adherent pathogens, suggesting very strong attachment. Episcopic differential interference contrast microscopy is a rapid alternative to both scanning electron microscopy and confocal laser scanning microscopy for visualizing leaf topography and biofilm formation in the natural state. [source] Efficacy of intervention strategies for bioremediation of crude oil in marine systems and effects on indigenous hydrocarbonoclastic bacteriaENVIRONMENTAL MICROBIOLOGY, Issue 6 2007Boyd A. McKew Summary There is little information on how different strategies for the bioremediation of marine oil spills influence the key indigenous hydrocarbon-degrading bacteria (hydrocarbonoclastic bacteria, HCB), and hence their remediation efficacy. Therefore, we have used quantitative polymerase chain reaction to analyse changes in concentrations of HCB in response to intervention strategies applied to experimental microcosms. Biostimulation with nutrients (N and P) produced no measurable increase in either biodegradation or concentration of HCB within the first 5 days, but after 15 days there was a significant increase (29%; P < 0.05) in degradation of n -alkanes, and an increase of one order of magnitude in concentration of Thalassolituus (to 107 cells ml,1). Rhamnolipid bioemulsifier additions alone had little effect on biodegradation, but, in combination with nutrient additions, provoked a significant increase: 59% (P < 0.05) more n -alkane degradation by 5 days than was achieved with nutrient additions alone. The very low Alcanivorax cell concentrations in the microcosms were hardly influenced by addition of nutrients or bioemulsifier, but strongly increased after their combined addition, reflecting the synergistic action of the two types of biostimulatory agents. Bioaugmentation with Thalassolituus positively influenced hydrocarbon degradation only during the initial 5 days and only of the n -alkane fraction. Bioaugmentation with Alcanivorax was clearly much more effective, resulting in 73% greater degradation of n -alkanes, 59% of branched alkanes, and 28% of polynuclear aromatic hydrocarbons, in the first 5 days than that obtained through nutrient addition alone (P < 0.01). Enhanced degradation due to augmentation with Alcanivorax continued throughout the 30-day period of the experiment. In addition to providing insight into the factors limiting oil biodegradation over time, and the competition and synergism between HCB, these results add weight to the use of bioaugmentation in oil pollution mitigation strategies. [source] Ultrasonic treatment of waste activated sludgeENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 2 2006Raf Dewil Abstract Activated sludge processes are key technologies to treat wastewater. These biological processes produce huge amounts of waste activated sludge (WAS), now commonly called biosolids. Mechanical, thermal, and/or chemical WAS conditioning techniques have been proposed to reduce the sludge burden. The ultrasonic treatment of WAS is quite novel. The present paper reports on extensive investigations using an ultrasonic treatment of WAS, to study its potential to meet one or all of four objectives: (1) reduce WAS quantities; (2) achieve a better dewaterability; (3) provoke a release of soluble chemical oxygen demand (COD) from the biosolids, preferably transformed into biodegradable organics; and (4) possibly destroy the filamentous microorganisms responsible for sludge bulking. Although meeting these objectives would help to solve the problems cited, the energy consumption could be a considerable drawback: the paper will thus assess whether all or some objectives are met, and at what operational cost. A literature survey defines the occurring phenomena (cavitation) and the important operation parameters [such as frequency, duration, specific energy input (SE)]. The experiments are carried out in a batch reactor of volume up to 2.3 L. The ultrasonic equipment consisted of a generator, a converter, and a sonotrode, supplied by Alpha Ultrasonics under the brand name of Telsonic. Three different kinds of sludge were tested, with different concentrations of dry solids (DS) between approximately 3.5 and 14 g DS/L WAS. Ultrasonic energy was introduced in a continuous manner (against possible pulsed operation). The major operational parameters studied include duration of the ultrasonic treatment and specific energy input. The applied frequency was set at 20 kHz. The release of COD from the WAS phase into the filtrate phase is a function of the specific energy input with yields of nearly 30% achievable at SE values of 30,000 kJ/kg DS. A major fraction of the COD is transformed into biodegradable organics (BOD). The reduction in DS fraction of the sludge is proportional to the COD release rates. Although the DS content is reduced, the dewaterability of the sludge is not improved. This reflects itself in increased filtration times during vacuum filtration and in increased values of the capillary suction time (CST). This more difficult dewaterability is the result of considerably reduced floc sizes, offering an extended surface area: more surface water is bound (CST increases) and the filterability decreases as a result of clogging of the cake. To reach the same dryness as for the untreated cake, the required dosage of polyelectrolyte is nearly doubled when the SE of the ultrasound treatment is increased from 7500 to 20,000 kJ/kg DS. The ultrasonic reduction of filamentous WAS organisms is not conclusive and very little effect is seen at low intensities and short treatment durations. Microscopic analysis of the WAS identified the dominant presence of Actynomyces. The release of soluble COD and BOD certainly merit further research. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] Observed and predicted reproduction of Ceriodaphnia dubia exposed to chloride, sulfate, and bicarbonate,ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2010Peter J. Lasier Abstract Chronic toxicities of Cl,, SO, and HCO to Ceriodaphnia dubia were evaluated in low- and moderate-hardness waters using a three-brood reproduction test method. Toxicity tests of anion mixtures were used to determine interaction effects and to produce models predicting C. dubia reproduction. Effluents diluted with low- and moderate-hardness waters were tested with animals acclimated to low- and moderate-hardness conditions to evaluate the models and to assess the effects of hardness and acclimation. Sulfate was significantly less toxic than Cl, and HCO in both types of water. Chloride and HCO toxicities were similar in low-hardness water, but HCO was the most toxic in moderate-hardness water. Low acute-to-chronic ratios indicate that toxicities of these anions will decrease quickly with dilution. Hardness significantly reduced Cl, and SO toxicity but had little effect on HCO. Chloride toxicity decreased with an increase in Na+ concentration, and HCO toxicity may have been reduced by the dissolved organic carbon in effluent. Multivariate models using measured anion concentrations in effluents with low to moderate hardness levels provided fairly accurate predictions of reproduction. Determinations of toxicity for several effluents differed significantly depending on the hardness of the dilution water and the hardness of the water used to culture test animals. These results can be used to predict the contribution of elevated anion concentrations to the chronic toxicity of effluents; to identify effluents that are toxic due to contaminants other than Cl,, SO, and HCO; and to provide a basis for chemical substitutions in manufacturing processes. Environ. Toxicol. Chem. 2010;29:347,358. Published 2009 SETAC [source] Effect of ethoxylate number and alkyl chain length on the pathway and kinetics of linear alcohol ethoxylate biodegradation in activated sludgeENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2004Nina R. Itrich Abstract Batch activated-sludge die-away studies were conducted with various pure homologs to determine the effect of ethoxylate number and alkyl chain length on the kinetics of primary and ultimate biodegradation of linear alcohol ethoxylates. The 14C-(ethoxylate) homologs C14E1, C14E3, C14E6, and C14E9 were used to investigate the effect of ethoxylate number, and 14C-(ethoxylate) homologs C12E6, C14E6, and C16E6 were used to examine the effect of chain length. Activated sludge was dosed with a trace concentration (0.2 ,M) of each homolog, and the disappearance of parent, formation of metabolites, production of 14CO2, and uptake into solids were monitored with time. Ethoxylate number had little effect on the first-order decay rates for primary biodegradation, which ranged from 61 to 78 h,1. However, alkyl chain length had a larger effect, with the C16 chain-length homolog exhibiting a slower rate of parent decay (18 h,1) compared to its corresponding C12 and C14 homologs (61,69 h,1). Ethoxylate number affected the mechanism of biodegradation, with fission of the central ether bond to yield the corresponding fatty alcohol and (poly)ethylene glycol group increasing in dominance with increasing ethoxylate number. Based upon the measured rates of primary biodegradation, removal of parent during activated-sludge treatment was predicted to range between 99.7 and 99.8% for all homologs except C16E6, which had a predicted removal of 98.9%. Based upon the measured rates of ultimate biodegradation, removal of ethoxylate-containing metabolites was predicted to exceed 83% for all homologs. These predictions corresponded closely with previously published removal measurements in laboratory continuous activated-sludge systems and actual treatment plants. [source] Response of zooplankton communities to liquid creosote in freshwater microcosmsENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 2 2001Paul K. Sibley Abstract In this study, the response of zooplankton communities to single applications of liquid creosote in model aquatic ecosystems (microcosms) was evaluated. Liquid creosote was applied to 14 microcosms at concentrations ranging from 0.06 to 109 mg/L. Two microcosms served as controls. Zooplankton samples were collected from each microcosm on days 7 and 1 before treatment and on days 2, 5, 7, 14, 21, 28, 43, 55, and 83 following treatment. Temporal changes (response-recovery) in composition of the zooplankton community were assessed using principal response curves (PRC). Creosote induced a rapid, concentrationdependent reduction in zooplankton abundance and number of taxa, with maximum response (50,100% reduction in population densities) occurring between 5 and 7 d after treatment. Taxa that dominated at the time of treatment experienced the greatest impact, as indicated by large, positive species weight values (>1) from the PRC analysis. Many of these taxa recovered to pretreatment or control levels during the posttreatment period, with the degree and duration of recovery being strongly dependent on concentration. Creosote had little effect on species composition at less than 1.1 mg/L, because changes in the types and relative proportion of species contributed from Cladocera, Rotifera, and Copepoda were comparable to those observed in control microcosms. However, a significant shift in species composition was observed at concentrations greater than 1.1 mg/L; these microcosms were generally dominated by low numbers of rotifers, some of which had not been collected before treatment. Community-level effect concentrations (EC50s) were 44.6 and 46.6 ,g/L at 5 and 7 d, respectively, based on nominal creosote. Corresponding no-effect concentrations were 13.9 and 5.6 ,g/L. The results of this field study indicate that creosote may pose a significant risk to zooplankton communities at environmental concentrations potentially encountered during spills and/or leaching events. [source] Cd, Cu, Pb, and Zn coprecipitates in Fe oxide formed at different pH: Aging effects on metal solubility and extractability by citrateENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 1 2001Carmen Enid Martínez Abstract Coprecipitates of heavy metals with Fe oxides may form in contaminated soil, water, and sediment systems, particularly when oxidation-reduction processes are occurring. Once formed, coprecipitates with ferrihydrite could limit heavy metal mobility, solubility, toxicity, and bioavailability in geochemical systems. In this study, Cd, Cu, Pb, and Zn were coprecipitated with Fe by titration to pHs 6 and 7. Metal solubility was monitored during the coprecipitation process to pH 7 and after aging of the product. In the coprecipitate formed at pH 6, metal solubility was determined after the system reached pH 6 and at subsequent time intervals. We also reacted the coprecipitates with citrate and evaluated potential metal availability at increased aging times. The pH of coprecipitate formation had little effect on the long-term solubility of Cu and Zn, whereas soluble Cd was greater in the coprecipitate formed at pH 6. Soluble percentages of metals were low at both pH 6 and 7 for Cu and Pb but averaged 1.5 to 3% for Zn and greater than 40% for Cd. Hysteresis was observed in the coprecipitation curves for Zn and Cd, revealing reduced solubility after adsorption or coprecipitation. Lead and Cu failed to show hysteresis, with strong retention in the solid phase at pH greater than 6. The citrate-extractable fraction was greatest for Cd and Zn, less for Cu, and least for Pb. Citrate-extractable metal was higher for the coprecipitate formed at pH 7 than at pH 6, suggesting increased potential availability from coprecipitates formed at higher pH. [source] Guardians and handlers: the role of bar staff in preventing and managing aggressionADDICTION, Issue 6 2005Kathryn Graham ABSTRACT Aims To identify good and bad behaviors by bar staff in aggressive incidents, the extent these behaviors apparently reflect aggressive intent, and the association of aggressive staff behavior with level of aggression by patrons. Design, setting and participants Data on staff behavior in incidents of aggression were collected by 148 trained observers in bars and clubs on Friday and Saturday night between midnight and 2 a.m. in Toronto, Canada. Behaviors of 809 staff involved in 417 incidents at 74 different bars/clubs were analysed using descriptive statistics and three-level hierarchical linear modeling (HLM) analyses. Measurements Observers' ratings of 28 staff behaviors were used to construct two scales that measured escalating/aggressive aspects of staff behavior. Apparent intent level for bar staff was dichotomized into (1) no aggressive intent versus (2) probable or definite aggressive intent. Five levels of patron aggression were defined: no aggression, non-physical, minor physical, moderate physical and severe physical. Findings The most common aggressive behaviors of staff were identified. Staff were most aggressive when patrons were either non-aggressive or highly aggressive and staff were least aggressive when patrons exhibited non-physical aggression or minor physical aggression. Taking apparent intent into consideration decreased staff aggression scores for incidents in which patrons were highly aggressive indicating that some aggression by staff in these instances had non-aggressive intent (e.g. to prevent injury); however, apparent intent had little effect on staff aggression scores in incidents with non-aggressive patrons. Conclusion Although there is potential for staff to act as guardians or handlers, they often themselves became offenders when they responded to barroom problems. The practical implications are different for staff aggression with nonaggressive patrons versus with aggressive patrons. [source] | ||||||||||||||||||||||||||||||||||||||||||||||