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Small lakes ( Key words: lake, forestry, riparian, water quality, plankton, fish, Introduction There has been increased interest in recent decades regarding the connectivity within the freshwater landscape (e.g., Jones et al. 2019), with a growing recognition of stream, wetland (e.g., Fritz [...]

Lake deltas (LDs) receive nutrient and energy subsidies from upstream habitats. These inputs can support LD benthic production. However, LDs may also receive impacts from upstream disturbance. Small lakes in coastal British Columbia often have inflow streams from areas with forest harvesting, which is pervasive in this region. Forest harvesting impacts can alter stream production, although downstream impacts on lakes, compared to streams, are less studied and understood. We aimed to test whether benthic LD communities (biofilm and invertebrates) are more productive and (or) diverse compared to other communities along the lakeshore (LS) (non-LDs), and whether there are differences in LD communities associated with upstream harvesting. We compared LD communities with upstream riparian areas that were harvested (HLD) or relatively undisturbed (ULD), and LS sites. We found that while community structure was similar across sites, ULDs had higher biofilm and invertebrate standing stocks (1.5- and 2-times higher, respectively) than HLDs and LS sites. Our results suggest subsidies and benthic production were higher at ULDs. These results advance our understanding of forest harvesting disturbance and stream-lake connectivity. Key words: Stream, lake delta, lake, forestry, biofilm, invertebrates, Introduction Streams and lakes are interconnected throughout the riverscape (e.g., Jones 2010; Covino 2017); however, empirical research on stream connections to lakes has been somewhat limited (e.g., review in Jones [...]

Western red cedar (Thuja plicata Donn ex D.Don) is a dominant species in forests of the Pacific Northwest in North America, but little is known about its decomposition in riparian habitat. We experimentally tested how early-stage mass loss of cedar leaf litter varied with distance from the stream (five distances from 1 to 40 m away) and responded to nutrient and water additions near four headwater streams in southwestern British Columbia. We ran three coarse-mesh litterbag trials in durations between five months to one year from January 2013 and January 2014. Litterbags were either untreated or given the following treatments: water additions during dry summer months, nitrogen and phosphorus additions, or additions of both. Control litterbags lost 21% initial mass over 12 months (January 2013-January 2014), 20% over five months (January 2013-June 2013), and 15% over eight months (June 2013-January 2014). Rates of mass loss did not increase with water in any trial but did increase with nutrients in the 12-month trial. Litter located 40 m from the stream lost 7% more mass than that located 1 m away in this same trial. Our study indicates that cedar leaf litter mass loss responded primarily to nutrient additions. Key words: Thuja plicata, coniferous, decomposition, nitrogen, phosphorus. Le thuya geant (Thuja plicata Donn ex D.Don) est une espece dominante dans les forets du Pacific Northwest en Amerique du Nord, mais on connait peu de choses au sujet de sa decomposition dans les habitats riverains. Nous avons teste experimentalement la facon dont la perte de masse initiale de la litiere de feuilles du thuya geant varie en fonction de la distance d'un cours d'eau (cinq distances de 1 a 40 m) et reagi a l'apport de nutriments et d'eau pres de quatre cours d'eau de tete dans le sud-ouest de la Colombie-Britannique. Nous avons realise trois essais avec des sacs de litiere a maille large d'une duree de cinq mois a un an, de janvier 2013 a janvier 2014. Les sacs de litiere ont ete, soit non traites, soit traites comme suit: apports d'eau durant les mois secs d'ete, apports d'azote et de phosphore, ou apports d'eau et de nutriments. Les sacs de litiere temoins ont perdu 21% de leur masse initiale apres 12 mois (janvier 2013 a janvier 2014), 20% apres cinq mois (janvier a juin 2013), et 15% apres huit mois (juin 2013 a janvier 2014). Le taux de perte de masse n'a pas augmente avec l'apport d'eau dans aucun des essais mais il a augmente avec l'apport de nutriments dans l'essai d'une duree de 12 mois. La litiere situee a 40 m d'un cours d'eau a perdu 7% plus de masse que celle qui etait situee a un metre dans le meme essai. Notre etude indique que la perte de masse de la litiere de feuilles du thuya geant a surtout reagi a l'apport de nutriments. [Traduit par la Redaction] Mots-cles: Thuja plicata, coniferien, decomposition, azote, phosphore., Introduction Leaf litter decomposition is vital to biogeochemical cycles in forest ecosystems (Krishna and Mohan 2017). More than half of global annual production in forests enters detrital food webs (Gosz [...]

Tributary junctions are regarded as ecologically important due to unique habitat present; however, there is limited understanding of the drivers of habitat attributes at these locations. Using six sites across two mainstem rivers, we tested whether tributary size relative to main stem governs the strength and direction of response of substrate size, stream temperature, and nutrient and coarse particulate organic matter (CPOM) concentration. We found that only phosphorus and CPOM concentration showed a significant relationship with relative tributary size. Small tributaries contributed high concentrations, whereas concentrations in larger tributaries resembled the main stem. Often, tributary exports were enough to increase the resource concentration in the main stem by 40%. Substrate coarsened by ~60% downstream of tributaries. Temperature asynchrony was observed, where tributaries contributed water between 2.8[degrees]C cooler to 1.9[degrees]C warmer than the main stem within one diel period. Our results highlight the importance of small tributaries for whole network functioning. However, large spatiotemporal variability revealed how habitat attributes are highly context-dependent in these locations and may be difficult to predict in both scientific and management settings. Si les milieux de confluence d'affluents sont juges importants sur le plan ecologique en raison des habitats singuliers qu'ils recelent, la comprehension des facteurs qui influent sur les attributs d'habitats dans ces endroits est toutefois limitee. En utilisant six sites dans les cours principaux de deux rivieres, nous avons verifie si la taille de l'affluent par rapport a celle du bras principal regit la force et la direction des reactions en ce qui concerne la taille du materiau du substrat, la temperature dans le cours d'eau et les concentrations de nutriments et de particules organiques grossieres (POG). Nous constatons que seules les concentrations de phosphore et de POG presentent une relation significative avec la taille relative de l'affluent. Les petits affluents fournissent de fortes concentrations, alors que les concentrations dans les plus grands affluents sont semblables a celles du bras principal. Dans bien des cas, les exportations provenant d'affluents suffisent pour accroitre de 40 % la concentration de ressources dans le bras principal. La granulometrie du substrat augmente d'environ 60 % en aval d'affluents. Une asynchronie des temperatures est observee, les affluents fournissant de l'eau de 2,8[degrees]C plus froide a 1,9[degrees]C plus chaude que l'eau dans le bras principal sur une periode de 24 h. Nos resultats soulignent l'importance des petits affluents pour le fonctionnement du reseau dans son ensemble. Une grande variabilite spatiotemporelle revele toutefois une forte dependance des attributs de l'habitat sur le contexte dans ces lieux, qui peut compliquer la prediction de ces attributs dans le contexte tant de la recherche scientifique que de la gestion. [Traduit par la Redaction], Introduction Heterogeneity in food resources and the structural components of habitat influence the distribution of organisms, which are key agents of nutrient cycling, energy transfer, and provide many of the [...]

The influence of stream channel structure on the production of prey for drift-feeding fish is not well understood. We quantified drift production, the entry rate per streambed area, and drift flux, the total export rate per channel unit, in three second-order, forested streams in southwest British Columbia, Canada. We tested whether (1) drift production was higher in riffles than in pools, (2) drift flux increased with riffle length, and (3) prey body size was larger from riffles relative to pools and from terrestrial drop relative to aquatic drift. Total and aquatic-derived drift production (mg x [m.sup.-2] x [h.sup.-1]) was ~3.5 times higher in riffles relative to pools; however, terrestrial drift did not differ between channel types. Total drift flux (mg x [h.sup.-1]) was positively related to riffle length. Terrestrial invertebrates were approximately three times larger than aquatics, and invertebrates from riffles were approximately three times larger on average than those from pools. These results suggest that channel structure directly affects prey availability and prey quality for drift-feeding fish and that long riffles may be key areas of prey generation. L'influence de la structure du chenal d'un cours d'eau sur la production de proies pour les poissons se nourrissant d'organismes a la derive n'est pas bien comprise. Nous avons quantifie la production d'organismes a la derive, le taux d'entree par unite de surface du lit du cours d'eau et le flux d'organismes a la derive, soit le taux d'exportation total par unite de chenal, dans des cours d'eau forestiers de deuxieme et troisieme ordres du sud- ouest de la Colombie-Britannique (Canada). Nous avons verifie si (1) la production d'organismes a la derive etait plus grande dans les seuils que dans les fosses, (2) le flux d'organismes a la derive augmentait parallelement a la longueur du seuil et (3) la taille du corps des proies etait plus grande dans les seuils que dans les fosses et pour les proies provenant du milieu terrestre que pour les proies aquatiques a la derive. La production d'organismes a la derive totale et provenant du milieu aquatique (mg x [m.sup.-2] x [h.sup.-1]) etait ~3,5 fois plus grande dans les seuils que dans les fosses; cependant, la derive d'origine terrestre ne variait pas selon le type de chenal. Le flux d'organismes a la derive total (mg x [h.sup.-1]) etait positivement relie a la longueur du seuil. Les invertebres terrestres etaient environs trois fois plus grands que les invertebres aquatiques, et les invertebres issus des seuils etaient environs trois fois plus grands en moyenne que ceux des fosses. Ces resultats donnent a penser que la structure du chenal a une incidence directe sur la disponibilite et la qualite des proies pour les poissons qui se nourrissent d'organismes a la derive et que les longs seuils pourraient etre d'importantes zones de generation de proies., Introduction Invertebrate drift, the downstream transport of suspended macroinvertebrates, is a primary source of prey for many stream fishes including salmon and trout (Salmonidae). Together, drift abundance and habitat conditions [...]

Sedimentation is a pervasive cause of biological impairment in streams, and predation exerts strong control over lower trophic levels. However, studies combining these two factors are lacking. In a factorial experiment in flow-through channels, addition of sand ( La sedimentation est une cause largement repandue de degradation biologique dans les cours d'eau et la predation exerce un fort controle sur les niveaux trophiques inferieurs. Les etudes qui combinent ces deux facteurs font toutefois defaut. Dans une experience factorielle dans des chenaux a circulation continue, des ajouts de sable (, Introduction Anthropogenic influences pose a serious threat to biodiversity and ecosystem resilience via habitat loss and degradation (Strayer and Dudgeon 2010; Cardinale et al. 2012). Freshwater environments are among the [...]

Most studies of cross-ecosystem resource subsidies have demonstrated positive effects on recipient consumer populations, often with very large effect sizes. However, it is important to move beyond these initial addition-exclusion experiments to consider the quantitative consequences for populations across gradients in the rates and quality of resource inputs. In our introduction to this special issue, we describe at least four potential models that describe functional relationships between subsidy input rates and consumer responses, most of them asymptotic. Here we aim to advance our quantitative understanding of how subsidy inputs influence recipient consumers and their communities. In the papers following, fish were either the recipient consumers or the subsidy as carcasses of anadromous species. Advancing general, predictive models will enable us to further consider what other factors are potentially co-limiting (e.g., nutrients, other population interactions, physical habitat, etc.) and better integrate resource subsidies into consumer-resource, biophysical dynamics models. La plupart des etudes des apports de ressources entre ecosystemes ont demontre des effets positifs sur les populations de consommateurs recepteurs, dont, bien souvent, de tres grands effets sur la taille. Il importe toutefois d'aller au-dela de ces experiences initiales d'ajout-exclusion pour examiner les consequences quantitatives sur les populations le long de gradients du taux et de la qualite des apports de ressources. Dans notre article d'introduction au present numero special, nous decrivons au moins quatre modeles potentiels qui decrivent les relations fonctionnelles entre les taux d'apports de ressources et les reactions de consommateurs, la plupart etant asymptotiques. Nous tentons ainsi d'accroitre la comprehension quantitative de l'influence des apports sur les consommateurs recepteurs et les communautes dont ils font partie. Dans les articles suivants, des poissons representent soit des consommateurs recepteurs ou des apports, sous forme de carcasses d'especes anadromes. Le developpement de modeles predictifs generaux permettra d'evaluer quels autres facteurs pourraient etre colimitants (p. ex. nutriments, autres interactions de populations, habitat physique) et de mieux integrer les apports de ressources aux modeles biophysiques de la dynamique consommateurs-ressources. [Traduit par la Redaction], Introduction The importance of cross-ecosystem resource subsidies has been recognized in a variety of ecosystems for decades. Leaf detritus or dissolved organic matter entering freshwater food webs, sea wrack decomposing [...]

Invertebrate drift, the downstream transport of aquatic invertebrates, is a fundamental ecological process in streams with important management implications for drift-feeding fishes. Despite long-standing interest, many aspects of drift remain poorly understood mechanistically, thereby limiting broader food web applications (e.g., bioenergetics-based habitat models for fish). Here, we review and synthesize drift-related processes, focusing on their underlying causes, consequences for invertebrate populations and broader trophic dynamics, and recent advances in predictive modelling of drift. Improving predictive models requires further resolving the environmental contexts where drift is driven by hydraulics (passive drift) versus behaviour (active drift). We posit this can be qualitatively inferred by hydraulic conditions, diurnal periodicity, and taxa-specific traits. For invertebrate populations, while the paradox of population persistence in the context of downstream loss has been generally resolved with theory, there are still many unanswered questions surrounding the consequences of drift for population dynamics. In a food web context, there is a need to better understand drift-foraging consumer-resource dynamics and to improve modelling of drift fluxes to more realistically assess habitat capacity for drift-feeding fishes. La derive d'invertebres, soit le transport vers l'aval d'invertebres aquatiques, est un processus ecologique fondamental dans les cours d'eau qui a d'importantes consequences pour les poissons qui se nourrissent d'aliments a la derive. Malgre un interet de longue date, de nombreux aspects de la derive demeurent mal compris d'un point de vue mecaniste, ce qui limite les applications plus larges des reseaux trophiques (p. ex. les modeles d'habitat reposant sur la bioenergetique pour les poissons). Nous passons en revue et resumons les processus associes a la derive, en mettant l'accent sur leurs causes sous-jacentes, les consequences pour les populations d'invertebres et la dynamique trophique plus large, ainsi que les avancees recentes en modelisation predictive de la derive. L'amelioration des modeles predictifs necessite une meilleure resolution des milieux dans lesquels la derive est mue, d'une part, par l'hydraulique (derive passive) ou, d'autre part, par le comportement (derive active). Nous postulons que cela peut etre infere de maniere qualitative a partir des conditions hydrauliques, de la periodicite diurne et de caracteres propres aux taxons. Pour les populations d'invertebres, si le paradoxe de la persistance des populations dans le contexte de perte en aval a generalement ete resolu en faisant appel a la theorie, de nombreuses questions demeurent quant aux consequences de la derive pour la dynamique des populations. Dans un contexte de reseaux trophiques, il est necessaire de mieux comprendre la dynamique derive-consommateur s'alimentant-ressource et d'ameliorer la modelisation des flux de derive pour evaluer de maniere plus realiste la capacite des habitats pour les poissons se nourrissant de la derive. [Traduit par la Redaction], Introduction Invertebrate drift, the downstream transport of stream invertebrates, is a defining feature of running water systems at multiple levels of organization. For individuals, drifting may be a mode of [...]

Scholars from different disciplines have focused on articulated ironies rather than situational ironies. The latter should be understood as events. Their pattern of reversing a forecast is also present in articulated ironies. Understanding this helps elucidate the nature, motivation, and meaning of articulated ironies, and illuminates complex ironic texts., Scholars have generally neglected two related questions about irony. First, few have focused closely on situational irony, concentrating instead on verbal irony, or more broadly on articulated irony. The reason [...]

Understanding the impacts of hydrological drought, and the role that refugia play in mitigating these impacts, is crucial to the conservation of freshwater fishes. This is especially true for species adapted to riffles, which are typically the first habitats to dewater at low discharge. We examined the relationship among decreasing stream discharge, abundance, and habitat use for Nooksack dace (Rhinichthys cataractae ssp.), an endangered riffle-dwelling species. A complementary experimental manipulation examined the effects of flow on growth rate across a discharge gradient in riffle and pool habitats. We found that low-velocity habitats and decreased discharge in experimental channels result in reduced dace growth and that decreasing stream flow was coincident with declines in Nooksack dace abundance. This study demonstrates the sensitivity of Nooksack dace to hydrological drought, and insofar as Nooksack dace are ecologically typical of small riffle-dwelling invertivore fishes, our results suggest that use of pools does not mitigate sublethal effects of declining flows on growth, although pools may provide refuge from the most negative effects of drought (i.e., stranding of fish). La comprehension des impacts de la secheresse hydrologique et du role des refuges dans l'attenuation de ces impacts est un aspect cle de la conservation des poissons d'eau douce, en ce qui concerne tout particulierement les especes adaptees aux radiers, normalement les premiers habitats a s'assecher en situation de faible debit. Nous avons examine la relation entre la diminution du debit d'un cours d'eau et l'abondance et l'utilisation de l'habitat par le naseux de la Nooksack (Rhinichthys cataractae ssp.), une espece en voie de disparition qui frequente les radiers. Une manipulation experimentale complementaire a permis d'examiner les effets de l'ecoulement sur le taux de croissance le long d'un gradient de debit dans des habitats de radiers et fosses. Nous avons constate que les habitats de faible vitesse d'ecoulement et un debit reduit dans les lits experimentaux se traduisaient par une croissance plus faible des naseux, et qu'un debit reduit coincidait avec des baisses de l'abondance des naseux de la Nooksack. L'etude demontre la sensibilite des naseux de la Nooksack a la secheresse hydrologique et, dans la mesure oU ces poissons sont typiques, sur le plan ecologique, des poissons invertivores qui frequentent les radiers, nos resultats donnent a penser que l'utilisation de fosses n'attenue pas les effets subletaux de la reduction des debits sur la croissance, bien que les fosses puissent servir de refuge contre les effets les plus nefastes de la secheresse (c.-a-d. l'echouage de poissons). [Traduit par la Redaction], Introduction Extinction rates for species in fresh water are exceedingly high (Ricciardi and Rasmussen 1999), and in North America alone the number of imperiled freshwater fishes increased by 92% between [...]

Freshwater ecosystems and the fisheries they support are increasingly threatened by human activities. To aid in their management and protection, we outline nine key principles for supporting healthy and productive ecosystems based on the best available science, including laws of physics and chemistry apply to ecology; population dynamics are regulated by reproduction, mortality, and growth; habitat quantity and quality are prerequisites of fish productivity; connectivity among habitats is essential for movements of fishes and their resources; freshwater species and their habitats are tightly linked to surrounding watersheds; biodiversity can enhance ecosystem resiliency and productivity; global processes affect local populations; anthropogenic stressors have cumulative effects; and evolutionary processes can be important. Based on these principles, we provide general recommendations for managing and protecting freshwater ecosystems and the fisheries they support, with examples of successful implementation for each strategy. Key management strategies include engage and consult with stakeholders; ensure that agencies have sufficient capacity, legislation, and authority to implement policies and management plans; define metrics by which fisheries resources and management success or failure will be measured; identify and account for threats to ecosystem productivity; adopt the precautionary approach to management; embrace adaptive management; implement ecosystem-based management; account for all ecosystem services provided by aquatic ecosystems; protect and restore habitat as the foundation for fisheries; and protect biodiversity. Ecosystems are complex with many intertwined components and ignoring linkages and processes significantly reduces the probability of management success. These principles must be considered when identifying management options and developing policies aiming to protect productive freshwater ecosystems and sustainable fisheries. Key words: biodiversity, connectivity, cumulative effects, global processes, habitat, watershed. Les ecosystemes d'eau douce et les pecheries qu'ils supportent sont de plus en plus menaces par les activites humaines. Afin d'aider leur amenagement et leur protection, les auteurs etablissent neuf principes de base pour supporter des ecosystemes productifs et en sante, bases sur les meilleures connaissances disponibles, incluant les lois de la physique et de la chimie appliquees a l'ecologie; la dynamique des populations est regulee par la reproduction, la mortalite et la croissance; la quantite et la qualite des habitats constituent des prealables pour la productivite du poisson; la connectivite entre les habitats est essentielle pour les mouvements des poissons et de leurs ressources; les especes d'eau douce et leurs habitats sont etroitement relies aux bassins versants environnants; la biodiversite peut augmenter la resilience et la productivite des ecosystemes; les processus globaux affectent les populations locales; les agents stressants anthropogenes exercent des effets cumulatifs; et, les processus evolutifs peuvent etre importants. Bases sur ces principes, les auteurs proposent des recommandations generales pour l'amenagement et la protection des ecosystemes d'eau douce et des pecheries qu'ils supportent, avec des exemples de mises en place reussies de plans d'amenagement pour chaque strategie. Les strategies determinantes incluent : l'engagement et la consultation avec les parties prenantes; l'assurance que les agences ont la capacite, la legislation et l'autorite suffisantes pour mettre en oeuvre les politiques et les plans d'amenagement; la definition metrique par laquelle seront mesures les succes ou les echecs des ressources et de l'amenagement des pecheries; l'identification et la prise en compte des menaces a la productivite des ecosystemes; l'adoption de l'approche par precaution dans l'amenagement; viser l'amenagement adaptatif, mettre en place l'amenagement base sur l'ecosysteme; tenir compte de tous les services ecosystemiques fournis par les ecosystemes aquatiques; proteger et restaurer l'habitat en tant que base des pecheries; et proteger la biodiversite. Avec plusieurs composantes inter reliees, les ecosystemes sont complexes et l'ignorance des liens et des processus reduit significativement la probabilite du succes de l'amenagement. Ces principes doivent etre consideres lorsque l'on identifie des options d'amenagement et definit des politiques visant a proteger les ecosystemes d'eau douce productifs pour des pecheries durables. [Traduit par la Redaction] Mots-cles: biodiversite, connectivite, effets cumulatifs, processus globaux, habitat, bassin versant., Introduction Freshwater ecosystems are among the most imperiled on Earth (Richter et al. 1997; Strayer and Dudgeon 2010), with extinction rates of freshwater fauna higher than for many other ecosystems [...]

ABSTRACT A field and modeling study of the food supply and demand of mussel (Mytilus edulis) rafts in Maine established the hydrodynamic and particle consumption characteristics of shellfish aquaculture structures. [...]

Blood Swept Lands and Seas of Red, 'Dulce et Decorum Est,' and The Things They Carried represent war through sentimental witnesses. The trend goes back to eighteenth-century sentiment and to writers of the American Revolution. This mode of war representation raises ethical and rhetorical concerns., The acrimonious debate concerning the Tower of London's 2014 commemoration of the outbreak of World War I, Blood Swept Lands and Seas of Red, revealed common assumptions about the nature [...]

Erik Jan van Rossum and Rebecca Hamer: The meaning of learning and knowing Sense Publishers, 2010 This is an unusual and potentially important book. It constitutes the joint PhD thesis [...]

Changes in riparian forest composition and diversity, such as plantations of exotic species, may alter resource quality, detritivore assemblages, and litter breakdown rates in streams. We hypothesized that different litter resources may influence colonization and drift of invertebrates inhabiting small, temperate rainforest streams in southwestern British Columbia, Canada. Leaves of different quality and origin were incubated in stream-side channels to test this hypothesis. The sequence of leaf decomposition rates was as follows: alder > alder + cedar > cedar > eucalyptus. Cedar litter decayed faster when mixed with alder than when alone. Invertebrates colonizing leaf bags were predominantly collector-gatherers and shredders, particularly on alder leaves. Drift density varied over the incubation period and seemed to be controlled by leaf quality, since there were more individuals drifting from channels with alder leaves than from channels with cedar or eucalyptus. However, we observed different species-specific invertebrate responses controlled by leaf traits, particularly by numerically dominant chironomid species. Indeed, invertebrate drift from channels incubated with alder bags was mostly due to pupation and emergence of orthoclad midges, whereas this was not observed in the other channels. This differential response in colonization and drift has the potential to modify the transfer rates of organic matter to higher trophic levels and thus ecosystem functioning. Des changements dans la composition et la diversite des forets riveraines, comme la plantation d'especes exotiques, peuvent modifier la qualite des ressources, les assemblages de detritivores et le taux de decomposition de la litiere dans les cours d' eau. Nous avons postule que differentes ressources de litiere pourraient influencer la colonisation et la derive d' invertebres habitant de petits cours d' eau de forets humides temperees dans le sud-ouest de la Colombie-Britannique (Canada). Des feuilles de qualites et d'origines differentes ont ete incubees dans des chenaux au fil de l'eau afin de verifier cette hypothese. La sequence des taux de decomposition des feuilles, en ordre decroissant, etait la suivante : aulne > aulne + thuya > thuya > eucalyptus. La litiere de thuya se decomposait plus rapidement quand elle etait melangee avec de la litiere d' aulne que par elle-meme. Les invertebres qui colonisaient les sacs de feuilles etaient principalement des collecteurscueilleurs et des dechiqueteurs, en particulier sur les feuilles d' aulne. La densite des invertebres dans le materiel en derive variait selon la periode d' incubation et semblait etre controlee par la qualite des feuilles puisqu' il y avait plus d' individus derivant de chenaux contenant des feuilles d' aulnes que de chenaux contenant des feuilles de thuya ou d' eucalyptus. Nous avons toutefois observe differentes reponses pour des especes d' invertebres donnees selon les caracteres des feuilles, en particulier chez les especes de chironomides, les invertebres les plus nombreux. En effet, la derive de chenaux ou etaient incubes des sacs de feuilles d'aulne etait principalement due a la pupaison et a l'emergence d'orthocladines, un phenomene non observe dans les autres chenaux. Ces differentes reponses sur le plan de la colonisation et de la derive pourraient modifier les taux de transfert de matiere organique vers des niveaux trophiques plus eleves et ainsi la dynamique des ecosystemes. [Traduit par la Redaction], Introduction Factors controlling the productivity and biodiversity of ecosystems are an important focus in ecology, and heterotrophic headwater streams dependent on particulate detritus are excellent systems for examining these processes [...]

The Robins Center: Is Less More? The Robins Center at the University of Richmond, home of Richmond's men's and women's basketball teams, had hosted a Presidential debate in 1992, but [...]

Previous studies of 'the Chinese learner' have confounded the effects of culture and context or have used heterogeneous samples of students. In this study, 134 British students and 207 students from mainland China following 1-year postgraduate programmes at six British business schools completed the Course Experience Questionnaire (CEQ) and the Revised Approaches to Studying Inventory (RASI). The two groups yielded the same factor structure on both instruments. There were no significant differences in their scores on the CEQ. On the RASI, the British students produced higher scores on deep approach and strategic approach. These differences could not be attributed to differences in response style. In short, when British and mainland Chinese students were compared within the same educational context, their perceptions and approaches to studying showed the same underlying constructs, but in the present context Chinese students were less likely to exhibit deep or strategic approaches to studying. Keywords Approaches to studying * Chinese students * Course Experience Questionnaire * Perceptions of learning environment * Revised approaches to studying inventory, Introduction Interview-based research carried out in the 1970s identified three predominant approaches to studying among students in higher education: a deep approach aimed at understanding the meaning of course materials; [...]

The food webs of forest stream ecosystems are based primarily on cross-boundary flows of terrestrial plant litter (PL). As such, changes in the composition of riparian forest canopies can alter flows of PL, affecting the ecosystem functioning of adjacent streams. We measured seasonal changes in PL fluxes to 20 small streams flowing through temperate rain forests in southwestern British Columbia to determine how riparian forest type and riparian management history influence resource availability in these systems. Differences in PL fluxes among the four riparian forest types studied were most pronounced in the summer, when PL fluxes from clearcuts < riparian reserve strips and coniferous forests, and PL fluxes from deciduous-dominated forests < riparian reserve strips. PL fluxes also varied among seasons (spring < summer < autumn). Fluxes were similar in riparian reserve strips and coniferous forests of similar age, indicating that reserve strips maintain this crucial ecosystem process. Clearcutting of riparian forests dramatically increased light availability while reducing leaf litter inputs; these effects, however, lasted only a few years. As riparian forest stand age increased, inputs shifted from broadleaf to coniferous inputs, indicating a possible long-term decrease in the lability of the leaf litter resources available to stream consumers. Resume: Les reseaux trophiques des ecosystemes de cours d'eau forestier sont principalement bases sur les flux transfrontaliers de litiere vegetale (LV) terrestre. Comme tels, les changements dans la composition du couvert forestier riverain peuvent modifier le flux de LV et influencer le fonctionnement des ecosystemes des cours d'eau adjacents. Nous avons mesure les changements saisonniers dans le flux de LV vers 20 petits cours d'eau coulant a travers des forets pluviales temperees du sud-ouest de la Colombie-Britannique pour determiner comment le type de foret riveraine et l'amenagement riverain passe influencent la disponibilite des ressources dans ces systemes. Les differences dans les flux de LV entre les quatre types de foret riveraine etudies etaient maximales durant l'ete, alors que les flux de LV dans les coupes a blanc etaient plus faibles que dans les bandes riveraines de protection et les forets de coniferes, et que les flux dans les forets dominees par les feuillus etaient plus faibles que dans les bandes riveraines de protection. Les flux de LV variaient aussi selon les saisons (printemps < ete < automne). Les flux etaient semblables dans les bandes riveraines de protection et les forets de conifers du meme age, ce qui indique que les bandes riveraines de protection maintiennent ce processus crucial de l'ecosysteme. La coupe a blanc des forets riveraines a beaucoup augmente la disponibilite de la lumiere tout en reduisant l'apport de litiere de feuilles; ces effets n'ont cependant dure que quelques annees. Avec l'augmentation de l'age des peuplements forestiers riverains, les apports sont passes de feuillus a resineux, ce qui indique qu'il y aura probablement une diminution a long terme de la labilite des ressources provenant de la litiere de feuilles disponibles pour les consommateurs dans les cours d'eau. [Traduit par la Redaction], Introduction Terrestrially derived plant detritus is a critical resource upon which the food webs of forest streams are based (Fisher and Likens 1973; Webster and Benfield 1986; Hall et al. [...]

THE STUDY examined attitudes toward teaching reported by university instructors who normally teach hearing students (with the occasional deaf or hard of hearing student) and by instructors who normally teach deaf and hard of hearing students at the same institution. Overall, a view of instruction as information transmission was associated with a teacher-focused approach to instruction, whereas viewing instruction as a means of promoting conceptual change was associated with a student-focused approach. Instructors in mainstream classrooms were more oriented toward information transmission than conceptual change, whereas instructors experienced in separate classrooms for deaf and hard of hearing students reported seeking to promote conceptual change in students and adopting more student-focused approaches to teaching. These results are consistent with previous findings concerning instructors' approaches to teaching and deaf and hard of hearing students' approaches to learning, and may help explain recent findings regarding student outcomes in separate versus mainstream secondary classrooms.

The study aims to evaluate the efficacy and safety of use of an implantable gentamicin-collagen sponge on stemal wound infections following cardiac surgery. The results indicate that the use of such sponge in the case of patients with diabetes, high body mass index or both did not show any benefits in reducing the infection.

Identification of critical habitat is a key step in conservation and recovery of endangered and threatened freshwater fish. Critical habitat under Canadian and US legislation may include habitat that is not directly used by listed fish, provided it is necessary for species conservation or recovery. Riparian habitat meets biological criteria for critical habitat because riparian zones are integral to aquatic ecosystem functions of importance to many fish species and other organisms. These functions include provision of shade for temperature-sensitive species, control of channel complexity and sediment inputs through bank stabilization, input of large wood and allochthonous energy sources, and filtering of nutrients and toxins from adjacent land. In response to decades of stream-riparian research, widespread implementation of regulations to protect riparian zones in most developed countries represent a de facto consensus that riparian buffers are essential for aquatic ecosystem health and the maintenance of populations of fish and other species. Consistent with widespread riparian regulations deemed necessary to protect not-at-risk species, riparian habitat adjacent to a body of water containing a listed freshwater species should be considered biologically critical unless the habitat requirements of individual taxa are demonstrated to be insensitive to the ecological functions associated with riparian habitat. Resume: L&apos;identification de l&apos;habitat critique est une etape essentielle dans la conservation et la recuperation des poissons d&apos;eau douce menaces et en voie de disparation. Dans les legislations canadienne et americaine, l&apos;habitat critique peut inclure des milieux qui ne sont pas directement utilises par les poissons concernes, a la condition qu&apos;ils soient necessaires pour la conservation ou la recuperation de ces especes. Les habitats riverains possedent les criteres biologiques d&apos;habitats critiques parce que les zones riveraines sont necessaires pour assurer des fonctions de l&apos;ecosysteme aquatique d&apos;importance pour plusieurs especes de poissons et pour d&apos;autres organismes. Ces fonctions incluent la production d&apos;ombre pour les espe ces sensibles a la temperature, le controle de la complexite du chenal et des apports de sediments par la stabilisation des rives, l&apos;apport de sources d&apos;energie allochtones et de debris ligneux de grande taille et la filtration des nutriments et des toxines provenant des terres adjacentes. A la suite de decennies de recherche sur la relation entre les cours d&apos;eau et la zone riveraine, la mise en application tres commune dans la plupart des pays developpes de reglements pour proteger les zones riveraines represente un consensus de facto reconnaissant que les zones tampons riveraines sont essentielles a la sante des ecosystemes aquatiques et le maintien des populations de poissons et d&apos;autres especes. En accord avec les reglements largement repandus sur les zones riveraines jugees necessaires pour la protection des especes non vulnerables, tout habitat riverain adjacent a un milieu aquatique contenant une espece d&apos;eau douce figurant sur la liste des especes en peril devrait etre considere comme biologiquement critique, a moins quon demontre que les besoins d&apos;habitat de ce taxon particulier sont insensibles aux fonctions ecologiques associees a lhabitat riverain. [Traduit par la Redaction], Introduction Canada's new legislation to protect endangered species, the Species At Risk Act (SARA; Government of Canada 2002), has been in place since 2002. As with most nascent environmental legislation [...]

Emergency brake assist, adaptive cruise control, and alternative instantiations of intelligent vehicle control systems aspire to support the driver in controlling the vehicle and alleviate the incidents that would lead to collisions and injury. This paper resets to zero and based on data from the on-the-spot accident study challenges the capability of active safety systems to aim at the sources of longitudinal control failures. The road user interactions file from 3,024 road accidents in Thames Valley and Nottinghamshire in U.K. was analyzed. Interactions where 'failure to stop' or 'sudden braking' is the precipitating factor are analyzed and the main contributory factors are identified. Some of those factors are addressed by current and coming technologies--such as low road friction, excessive speed, and close following, but other common ones are significantly neglected--such as distraction, failure to judge other person's path, failure to look, and 'look, but did not see' instances. DOI: 10.1061/(ASCE)TE.1943-5436.0000042 CE Database subject headings: Safety; Traffic accidents; Vehicles; Artificial intelligence; Control systems. Author keywords: Microscopic accident investigation; Active safety; Road accidents; Longitudinal vehicle control.

Riparian reserves designed to protect stream ecosystems are valuable to the conservation of riparian obligate and forest-preferring species; however, there have been few studies of terrestrial invertebrates with more general habitat requirements. To characterize the use of riparian reserves by terrestrial insects, we examined the ecology of Scaphinotus angusticollis Mannerheim, a large and abundant carabid beetle with a broad distribution in coniferous forests of western North America. Population sizes and movement behaviour of S. angusticollis were contrasted among clearcuts, 30 m reserves, and unharvested riparian forests near Vancouver, British Columbia, Canada, with three sites per habitat type. The relative abundances of S. angusticollis were as high in 30 m reserve habitats as they were in unharvested forests, whereas populations in clearcuts were approximately half the size of those found in 30 m reserves. Beetle distributions relative to nearby streams were similar across habitat types. Beetles moved twice as far in 30 m reserves than in clearcuts, suggesting there are differences in this beetle's perception of reserve habitat. This study provides evidence that 30 m riparian reserves offer habitat that maintains population sizes and facilitates movement of terrestrial insect species like S. angusticollis at levels similar to that of unharvested riparian forests. Resume: Les reserves riveraines concues pour proteger les ecosystemes de ruisseaux sont precieuses pour la conservation des especes preferant les couverts forestiers et infeodees au milieu riverain. Toutefois peu d'etudes ont verifie si c'etait aussi le cas pour les invertebres terrestres ayant des exigences d'habitat plus generales. Pour caracteriser l'utilisation des reserves riveraines par les insectes terrestres, nous avons examine l'ecologie de Scaphinotus angusticollis Mannerheim, un gros carabe abondant dans plusieurs types de forets de coniferes de l'ouest de l'Amerique du Nord. La taille des populations et le comportement de deplacement de S. angusticollis ont ete compares entre des coupes a blanc, des reserves de 30 m et des forets riveraines non recoltees pres de Vancouver, Colombie-Britannique, au Canada, a raison de trois stations par type d'habitat. L'abondance relative de S. angusticollis etait aussi elevee dans les reserves de 30 m que dans les forets non recoltees tandis que dans les coupes a blanc la taille des populations n'atteignait qu'environ la moitie de celles des reserves de 30 m. La repartition des carabes en fonction de la distance des ruisseaux etait la meme dans tous les types d'habitat. Les carabes se deplacaient deux fois plus loin dans les reserves de 30 m que dans les coupes a blanc, ce qui indique que ce carabe a une perception differente des habitats de reserve. Cette etude demontre que les reserves riveraines de 30 m offrent un habitat qui permet de maintenir la taille des populations et facilite le deplacement des insectes terrestres tels que S. angusticollis aussi bien que dans les forets riveraines non recoltees. [Traduit par la Redaction], Introduction Conservation efforts need to examine (i) the impacts of resource extraction activities, (ii) how these impacts are mitigated by management strategies (Hilderbrand et al. 2005), and (iii) how non-target [...]

Habitat loss and fragmentation are among the best documented explanations for the dramatic declines amphibians are experiencing globally. The western toad (Anaxyrus boreas (Baird and Girard, 1852)) is an IUCN red-listed species whose distribution range has been significantly affected by habitat modification. We used radiotelemetry to follow daily, postbreeding movement patterns of 23 adult male toads in a fragmented landscape near Vancouver, British Columbia, Canada, composed of forest patches and small, recent clearcuts (~5 ha). Results showed that toads in forests oriented towards edges of clearcuts from at least as far as 150 m. Greater than 60% of toads released in forest patches chose to enter the clearcuts from adjacent forests, indicating high boundary permeability. Net displacement distance was not significantly reduced in these clearcuts; however, movement rates were significantly lower on clearcuts than in forest. This indicates that there is no structural impediment to movements; however, there still could be fitness consequences or an interaction with summer weather. Toads also used roads for their movement more frequently than at random relative to their area. These results suggest that the western toad's movements may not be negatively affected by small-scale forest harvesting at our latitude during the spring. La perte et la fragmentation des habitats figurent parmi les causes les mieux etudiees du declin spectaculaire que les amphibiens subissent a l'echelle planetaire. Le crapaud de l'ouest (Anaxyrus boreas (Baird et Girard, 1852)) est une espece qui figure sur la liste rouge de l'UICN, dont l'etendue de la repartition a ete significativement affectee par la modification des habitats. La radio-telemetrie nous a servi a suivre les patrons quotidiens de deplacement de 23 crapauds males adultes apres la reproduction dans un paysage fragmente pres de Vancouver, Colombie-Britannique, Canada, compose de taches de forets et de petites (~5 ha) zones recentes de coupe a blanc. Les crapauds dans la foret s'orientent vers les bordures des zones de coupe a blanc a partir de distances pouvant atteindre an moins 150 m. Plus de 60 % des crapauds relaches dans des taches forestieres choisissent de penetrer dans les zones coupees a blanc a partir des forets adjacentes, ce qui montre une forte permeability des bordures. La distance nette de deplacement n'est pas significativement reduite dans ces zones coupees, bien que les taux de deplacement soient significativement plus has que dans les forets. Il n'existe donc pas d'empechement structurel an deplacement; il pent, cependant, y avoir des consequences sur la fitness on une interaction avec les conditions climatiques estivales. Les crapauds utilisent aussi les routes plus frequemment que de maniere aleatoire, compte tenu de la surface relative des routes. Nos resultats laissent croire que les deplacements des crapauds de l'ouest peuvent ne pas etre affectes negativement par la recolte forestiere a petite echelle a notre latitude an printemps. [Traduit par la Redaction], Introduction As the human footprint expands globally, habitat loss and fragmentation continue to increase (Vitousek et al. 1997; Sanderson et al. 2002). The resulting landscape is patchy, with areas of [...]

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.1559-1816.2008.00347.x Byline: John D. Richardson (a), William P. Huddy (a), Shawn M. Morgan (a) Abstract: This study examined the relation between 2 seemingly inconsistent phenomena: hostile media effect and biased assimilation. Participants (N = 156) reported their preference for George W. Bush or John Kerry and then viewed a live broadcast of the first Bush-Kerry Presidential debate. Consistent with biased assimilation, candidate preference influenced participants on both sides to perceive their candidate won the debate. Nevertheless, candidate preference modestly induced participants to perceive hostile bias from the debate moderator, Jim Lehrer. The influence of anticipated third-person effects was also examined. Overall, the results suggest biased assimilation and the hostile media effect are not inconsistent. In some situations, they occur simultaneously. Moreover, the hostile media effect appears to extend beyond news reports to other forms of mediation. Author Affiliation: (a)University of Colorado at Colorado Springs Article note: (2) John D. Richardson, 3515 Aspen Lake Drive, Manvel, TX 77578. E-mail: RichardsonPhD@gmail.com

The commercial computational fluid dynamics model FLOW-3D (Flow Science, Inc., Santa Fe, N.M.) is used to simulate two-dimensional wave transformation and breaking across a naturally barred beach profile. Fine scale pressures and velocities are computed for a 35.5 min period over a two-dimensional beach profile measured during the 1990 Delilah field experiment. The model is driven by observed wave spectra obtained in 8 m water depth, and results compared with a cross-shore array of pressure sensors and current meters extending from near the shoreline to beyond the surf zone and the spatial distribution of wave breaking patterns obtained from video data. In the calculations, wave breaking is a natural consequence of the fluid dynamics and does not require the use of empirical formulations or breaking criteria. Good agreement between modeled and observed wave height transformation, mean cross-shore flow, and wave breaking variability suggests that the model can be used as a numerical laboratory to study the wave breaking and dissipation process in detail, and perhaps lead to improved parametrizations for more computationally efficient numerical models. CE Database subject headings: Breaking waves; Coastal processes; Computational fluid dynamics technique; Fluid dynamics; Nearshore; Surf zone; Surface waves; Turbulence.

Abstract: In an estuarine mudflat connected to a mountainous stream, coarse leaf material from deciduous trees was examined for its utilisation by invertebrates, retention, and breakdown rate. Leaves from the [...]

Because of a series of editorial apologies for neglecting coverage of the civil rights movement, this article examines coverage of the 1963 Birmingham campaign in five prestige dailies to explore the social construction of news and the relationship between news organizations, their subjects, and their audiences. This study considers survey data that indicated regional attitudes toward civil rights and found coverage did not always reflect the views of a paper's readers. Southern newspapers tended to discredit movement leaders and their agenda, as well as to emphasize law enforcement's preparedness, while northern and western papers were sympathetic to the movement. The study specifically considers why a midwest paper was hostile to the movement in contradiction to its readers' pro-integration attitude.

To purchase or authenticate to the full-text of this article, please visit this link: http://dx.doi.org/10.1111/j.2007.0030-1299.15982.x Byline: Laurie B. Marczak, Trent M. Hoover, John S. Richardson Abstract: The rate at which subsidies move between habitats is a function not only of those factors that facilitate such transfers, but also of factors that limit or restrict the movement of subsidies. The interruption or redirection of subsidies by organisms foraging at the boundary between habitats, or trophic interception, has the potential to substantially restructure the food webs of recipient habitats. In this study we describe how a waterstrider, Aquarius remigis, limits the transfer of a subsidy across the land-water boundary. Prey interception varied with the type of stream habitat; on average, waterstriders in isolated pools intercepted 71.8% of experimental prey inputs of all sizes compared with 21.5% in connected pools and 0.8% in riffles. Across all stream habitat types, waterstriders consumed 43.2% of the experimental inputs of the smallest prey used, the prey size class most similar to natural inputs in our study area. We estimate that foraging waterstriders may intercept 0.3-1.2 kg of terrestrial prey subsidy for every 100 m of stream channel during three summer months, resources that could otherwise support 13-58 young-of-the-year salmonids. In controlled trials, waterstriders significantly altered the amount of terrestrial prey directly consumed by fish, while fish also altered waterstrider interception of those prey. Interestingly, when waterstriders and fish were present together, more terrestrial prey were lost to the streambed than when either or both of these consumers were absent, making this resource available to benthic detritivores, and facilitating the direct incorporation of terrestrial nutrients into stream detrital webs. Overall, we demonstrate that organisms that forage at habitat boundaries can control the quantity and quality of subsidies arriving in recipient habitats, potentially altering food web structures within those habitats. Article History: Manuscript Accepted 29 May 2007 Article note: L. B. Marczak (laurie@interchange.ube.ca), T. M. Hoover and J. S. Richardson, Dept of Forest Sciences, Faculty of Forestry, Forest Sciences Centre, Univ. of British Columbia, 2424 Main Mall, Vancouver, BC, Canada, V6T 1Z4. - TMH also at: Dept of Civil Engineering, Univ. of British Columbia, Canada.

An encoding system was implemented purely in software for sending H.264 video multicast to mobile devices. The H.264 encoder is a multi-threaded parallel-GOP encoder. It is capable of running in real-time with an AMD Opteron 1.8 GHz dual-core platform in baseline profile at CIF resolution at 1 Mbps. Real-time video encoding is accomplished with aggressive Single Instruction Multiple Data assembly code optimizations and advanced algorithms. A Time Control algorithm was developed to quell the mode decision process from spending too much time per frame. Transmission of the audio and video streams is on an IP layer over WiFi and DVB-H. DVB-H is chosen for its power saving and reliability features. Using the IP network, the encoder can be repurposed for applications other than mobile broadcast video. Index Terms--AVC, digital communication, digital TV, DVB-H, encoder, encoding, H.264, internet, mobile communication, mobility, real-time, software, TV Broadcasting, video coding, wireless.

The preparation of complexes of the 4-(2'-pyridyl)-1,2,3,5-dithiadiazolyl radical bidentate ligand with bis(hexafluoroacetylacetonato)-manganese(II) and with bis(hexafluoroacetylacetonato)copper(II) is presented. The spectroscopic and magnetic properties on comparison to Co(II) complex reveal that these complexes form dimers via intermolecular S..S contacts in the solid state.

Abstract: Forest harvesting in riparian areas can alter the leaf-litter inputs, shading, and stability of small streams, and many of the details of these impacts are known for coastal streams [...]

Studies of the effects of cross-habitat resource subsidies have been a feature of food web ecology over the past decade. To date, most studies have focused on demonstrating the magnitude of a subsidy or documenting its effect in the recipient habitat. Ecologists have yet to develop a satisfactory framework for predicting the magnitude of these effects. We used 115 data sets from 32 studies to compare consumer responses to resource subsidies across recipient habitat type, trophic level, and functional group. Changes in consumer density or biomass in response to subsidies were inconsistent across habitats, trophic, and functional groups. Responses in stream cobble bar and coastline habitats were larger than in other habitats. Contrary to expectation, the magnitude of consumer response was not affected by recipient habitat productivity or the ratio of productivity between donor and recipient habitats. However, consumer response was significantly related to the ratio of subsidy resources to equivalent resources in the recipient habitat. Broad contrasts in productivity are modified by subsidy type, vector, and the physical and biotic characteristics of both donor and recipient habitats. For this reason, the ratio of subsidy to equivalent resources is a more useful tool for predicting the possible effect of a subsidy than coarser contrasts of in situ productivity. The commonness of subsidy effects suggests that many ecosystems need to be studied as open systems. Key words: food webs; functional group; habitat productivity; habitat type; meta-analysis; productivity; resource subsidies; spatial ecology; taxonomic group; trophie level.