A comparison of community structure in regulated and unregulated reaches in the Upper Eel River, California

Flow regulation of rivers by impoundments and diversions can reduce hydrological variability. As a result, densities of algae and benthic macroinvertebrates often increase, but many sensitive taxa are lost, causing shifts across the food web. In Northern California, dams that reduce winter peak floods can result in the primary consumer community becoming dominated by grazers that are relatively invulnerable to predation, which can reduce the amount of energy transferred up the trophic levels. The steeper slope of the spring hydrograph recession limb downstream of a dam can also greatly impact instream diversity of periphyton, invertebrates and fish. The dam and diversion system on the upper Mainstem Eel River in Northern California has direct impacts on endangered salmon populations, but the effects of the dams on the greater ecosystem are not well understood. This study compared the seasonal algal and benthic macroinvertebrate communities from the Mainstem Eel River below Cape Horn Dam to that of the unregulated Middle Fork Eel River. The 2017 water year had above average rainfall, with several bankfull flows observed in the winter as well as elevated base flows in the summer in both rivers. Despite the wet water year in 2017, the regulation of flows by the dams still likely produced a shorter spring recession limb and, more importantly, a delay in peak summer temperatures in the Mainstem relative to the Middle Fork. Although the abundance and diversity of invertebrates were not notably different between the regulated and unregulated rivers, there did appear to be a variation in the food webs. By mid-summer, the unregulated Middle Fork developed into an ecosystem predominated by Cladophora and its epiphytes with numerous invertebrate grazers. Yet the Mainstem, especially immediately below the dam with the encroachment of vegetation, had less growth of the filamentous green algae (t(20)=4.61, p=0.0002) with lower mid-summer algal richness ((20)=2.53, p= 0.020), resulting in an invertebrate community more reliant on filtering fine organic matter with far fewer grazers (pCladophoraas well as the abundance and development of some key macroinvertebrate taxa, such as midges and small minnow mayflies relative to an unregulated reach. As the Middle Fork is an inherently warmer system, future studies are needed across a longitudinal gradient of the Mainstem over multiple water years to capture interannual variation and to ultimately determine the influence of the dams on riverine ecosystems

Drivers and Dynamics of Phytoplankton Communities and Harmful Algal Blooms in Mountain Lakes

Harmful cyanobacterial blooms (cyanoHABs) are a complex and widespread disturbance in freshwater water bodies, impacting water quality for wildlife and human populations. While cyanobacteria often bloom in warm lakes impacted by human development like agriculture, blooms are increasingly reported in cooler waters with limited development in the surrounding watershed. As much of cyanoHAB research has focused on lakes in highly developed watersheds, the understanding of factors leading to cyanobacteria dominance and blooms in the absence of major development remains limited. Mountain lakes can serve as ideal systems to study bloom-forming cyanobacteria in watersheds with minimal development. In addition, mountain lakes span natural gradients of productivity and climate due to the varied elevation and topography. Mountain lakes are also highly valued for recreation and habitat for sensitive species due to perceived pristine conditions, but are vulnerable to multiple stressors such as climate warming and increased atmospheric deposition of nutrients, which limit cyanobacteria growth. Therefore, the potential for cyanoHABs in mountain lakes is likely to rise in the near future, making it crucial to understand the drivers of cyanobacteria dominance and blooms in these sensitive lakes. The goal of this dissertation is to improve the understanding of drivers and dynamics of bloom-forming cyanobacteria in mountain lakes, including factors across lake to watershed scales, to temporal and spatial patterns in planktonic communities. I conducted field surveys to examine the physical and chemical conditions as well as the phytoplankton and other key biological communities in a set of Cascade Mountain lakes located in Oregon, USA. In Chapter 2, I used survey data and existing geospatial data to identify food web, lake, and watershed drivers, as well as interactions among drivers across scales on nitrogen (N)-fixing cyanobacteria, the common cyanoHAB taxa in the region. In Chapter 3, I examined the intra- and inter-annual variation in cyanoHABs and cyanotoxins relative to meteorological conditions and the bacterioplankton communities. Based on genetic sequencing and time integrated toxin monitoring, I determined possible temporal relationships and biological indicators of blooms and bloom toxicity. In Chapter 4, I used survey data as along with existing and interpolated trait data to assess how the top-down and bottom-up effects of grazing zooplankton and nutrients could have shaped phytoplankton communities functionally. I discuss the resulting implications for bloom-forming cyanobacteria dominance over other phytoplankton. I identified watershed size and hypolimnetic dissolved oxygen as key drivers of N-fixing cyanobacteria biomass likely through the regulation of limiting nutrients such as phosphorus. Temperature and rainfall did not correspond strongly to the blooms and toxins of N-fixing cyanobacteria across lakes, suggesting other meteorological factors as well as lake productivity may be more important. Yet further study is needed with high-frequency sampling and better characterization of meteorological conditions. In terms of the food web, I found grazing cladocerans were a significant factor for N-fixing cyanobacteria, likely via consumption of other phytoplankton. These grazers may be in turn influenced by fish populations. I also found additional biological indicators for cyanobacteria blooms as well as bloom toxicity in heterotrophic bacteria. Finally, I found high grazer abundances favor fast growing and small unicellular phytoplankton at relatively low nutrients, while increasing phosphorus favors colonial cyanobacteria capable of toxin production, such as N-fixing taxa. At high levels of grazers and phosphorus, toxigenic cyanobacteria likely dominate phytoplankton communities in mountain lakes. This dissertation sheds light on the key factors and indicators for N-fixing cyanobacteria dominance and cyanoHABs in mountain lakes. My results suggest that lake management agencies must consider how both landscape and within-lake factors may affect the risk for cyanoHABs, and how fish stocking increases risk via their impact on grazing zooplankton biomass and body size. As mountain lake monitoring is limited, my results suggest genetic identification of bacterial communities may provide a more time-integrated way to assess bloom development and toxicity. Determining how abiotic and biotic factors interact is needed to broaden management approaches since strict nutrient reduction programs have had mixed success in reducing cyanoHABs in lakes

Memórias de um "Pretérito imperfeito": uma leitura da obra de Bernardo Kucinski

A literatura brasileira contemporânea tem sido alvo de diversos debates no que se refere aos caminhos críticos e metodológicos de investigação das suas produções. Diante disso, este artigo tem como objetivo apresentar uma possibilidade de leitura do livro Pretérito imperfeito, de Kucinski (2017), uma publicação recente na história literária do país. Para isso, adotou-se a orientação metodológica qualitativa e bibliográfica juntamente com o embasamento teórico de autores como Cury (2008), Pellegrini (2011), entre outros, de forma a propor uma análise com foco na categoria ‘espaço’ enquanto caminho de interpretação para os elementos que compõem a obra e, que, por sua vez, são mediados pela linguagem. Nessa perspectiva, pode-se compreender como a potencialidade significativa da obra literária perpassa pelo papel atuante do leitor para além de receptor, uma vez que os significados do texto literário se realizam também a partir do diálogo com a formação social daqueles que leem a obra.Palavras-chave: Literatura brasileira. Bernardo Kucinski. Espaço. DOI: https://doi.org/10.47295/mgren.v10i3.343

Intolerable conduct in a constructive dismissal : an exploration of case law dealing with intolerable conduct.

Thesis (LL.M.)-University of KwaZulu-Natal, Durban, 2012.This paper focuses on the issue of constructive dismissal in terms of s186(e) of the Labour Relations Act 66 of 1995 which defines dismissal to include circumstances where an employee resigns because the employer has made continued employment intolerable. The purpose of this paper is to explore and describe case law on this issue and to consider what type of conduct has been regarded as intolerable by the courts in order to determine whether or not a case for constructive has been met

Mechanical effects caused by the variation of the load screw inclination in the orifice of the dynamic compression plate

OBJETIVO: Avaliar os efeitos mecânicos da inclinação do parafuso excêntrico sobre a compressão axial com placa. MÉTODOS: Corpos de prova artificiais simulando fragmentos de osso diafisário foram fixados com placa DCP® de 4,5mm de sete orifícios. Uma célula de carga registrou as forças de compressão axial no intervalo entre os fragmentos. Guias de perfuração excêntrica com inclinações em relação ao plano longitudinal e transversal da placa foram confeccionados para o experimento. A compressão foi medida em dois diferentes sítios do foco de fratura virtual. De acordo com a magnitude da inclinação e sua direção em relação ao orifício da placa, oito diferentes grupos foram constituídos. Os ensaios mecânicos registraram a força máxima e a força máxima efetiva. RESULTADOS: A inclinação do parafuso em direção contrária à da rampa de deslizamento do orifício da placa foi acompanhada de diminuição nos valores médios de força máxima e força máxima efetiva de compressão 0º > 10ºi (p < 0,001), 0º > 20ºi (p < 0,001), 0º > 25ºi (p < 0,001). CONCLUSÃO: Em modelo experimental, utilizando-se placas do tipo DCP® não pré-tensionadas, a inclinação na inserção de parafusos excêntricos promoveu alterações nos valores médios da força de compressão axial. Houve diferenças significativas (p < 0,05) para menos na compressão axial obtida na cortical subjacente à placa, quando da inserção de parafusos inclinados no plano longitudinal com direção oposta à da rampa de deslizamento do orifício DCP®.OBJECTIVE: To evaluate the mechanical effects of sloping the load screw on the axial compression with a dynamic plate. METHODS: Artificial parts simulating shaft fragments were fixated with a 4.5 mm, 7 orifice DCP® plate. A load cell recorded axial compression loads in the space between fragments. Eccentric perforation guides with inclinations to the longitudinal and transversal plan of the plate were made for the experiment. Compression was measured in two different sites of the virtual fracture focus. Eight different groups were formed according to the magnitude of inclination and its direction based on the plate orifice. Mechanical assays recorded maximum load and effective maximum load. RESULTS: Screw inclination contrary to the plate orifice sliding slope was related to decreased mean values of maximum compression load and maximum effective compression load 0º > 10ºi (p < 0,001), 0 > 20ºi (p < 0,001), 0º > 25ºi (p < 0,001). CONCLUSION: In an experimental model, using non pre-stressed DCP® plates, the inclination upon inserting load screws brought about changes in the mean values of axial compression load. There significant differences (p < 0,05) to lower axial compression obtained in the cortical adjacent to the plate when the screws were inserted in inclination with the longitudinal plane in the opposite direction of the sliding slope of the DCP® orifice

Open wedge tibial osteotomy: biomechanical relevance of the opposite cortex for the fixation method

OBJETIVO: Avaliar o impacto da integridade da cortical lateral osteo-tomia alta de tíbia (OAT) com cunha de abertura. MÉTODOS: Modelos experimentais artificiais em poliuretano foram fixados com placa DCP® 4,5mm. Cunhas de abertura foram confeccionadas para simular a distração da osteotomia alta da tíbia. Realizadas falhas na cortical lateral para simular fraturas e fixadas com diferentes tipos de parafusos. Ensaios de torção e compressão axial foram realizados. 04 diferentes grupos foram constituídos. RESULTADOS: As medidas de torção registradas no grupo com cortical íntegra foram superiores àquelas obtidas no grupo com cortical rompida (p<0,001) e estatisticamente equivalentes aos grupos com cortical rompida associado à parafuso de estabilização lateral de compressão ou de posição (p&gt;0,05). As medidas de compressão obtidas no grupo com cortical íntegra foram superiores aos demais grupos (p<0,001). Em torção e compressão não houve diferença estatística entre os tipos de parafuso de estabilização lateral (p&gt;0,05). CONCLUSÃO: A cortical lateral íntegra agrega estabilidade às osteotomias com cunha de abertura medial. Modelo com cortical íntegra evidenciou superioridade biomecânica em rigidez nos ensaios de torção e compressão. Nos ensaios torcionais, os modelos com falha de continuidade cortical com parafusos de estabilização lateral de compressão ou de posição apresentaram equivalência aos modelos com cortical íntegra.OBJECTIVE: To evaluate the role of lateral tibial cortex integrity in open wedge tibial osteotomy (OWTO). METHODS: Experimental models of polyurethane fibers, simulating tibial models and modified with open wedge osteotomies were fixed with DCP® straight 4.5 mm plates. Four groups were constituted: two with cortical integrity and two with a gap in the lateral tibial cortex. Biomechanical analysis of torsion and axial compression were performed. RESULTS: The measures of twist recorded in the group with cortical integrity were higher than those obtained in the group with noncontinuous cortices (p <0.001). The groups with cortical gap on the lateral side that were fixed with screws had a biomechanical behavior comparable to the group with cortical integrity. Measures of compression obtained in the group with full cortical integrity were greater than those of other groups (p <0.001). In torsion and compression, no statistical difference between lag and position screws on the lateral cortical was demonstrated (p&gt;0.05). CONCLUSION: Integrity of lateral tibial cortex adds stability to open wedge tibial osteotomies. Models with lateral cortical integrity demonstrated superiority in biomechanical stiffness even under torsion or compression. In torsion tests, models with a gap on the lateral cortex, fixed with a lag or position screw to promote lateral stabilization had similar biomechanical behavior to those with lateral cortex integrity

The latent structure and reliability of the emotional trait section of the Affective and Emotional Composite Temperament Scale (AFECTS)

Background: The Emotional and Affective Composite Temperament (AFECT) model describes originally six traits of volition, anger, inhibition (fear and caution subordinate factors), control, sensitivity, and coping. However, fear and caution have shown opposite relatioships with criteria-variables, indicating factor independence. Objective: The current investigation aimed to advance in the evaluation of the psychometric properties of the emotional trait section of the Emotional and Affective Composite Temperament Scale (AFECTS) by examining the suitability of a 7-factor structure and the reliability of each scale using data from a population-based sample. Methods: AFECTS was administered via face-to-face assessments in a single-session, population-based cross-sectional survey. Samples was composed of teenagers and adults (14 to 35 years). The latent structure and reliability were analyzed via structural equation modeling: confirmatory factor analysis was used to test the a priori correlated 7-factor model (with fear and caution designed as single-factors) and trait-scores reliability was assessed by the estimation of information curves. Results: Findings attested the suitability of the 7-factor model presumed to underline the item set of the traits section of AFECTS and information curve interpretation showed adequate levels of reliability for all trait-scores. Discussion: The 7-factor model showed robust indicators of construct validity for the AFECTS

An Efficient, Streamable Text Format for Multimedia Captions and Subtitles

International audienceIn spite of the high profile of media types such as video, audio and images, many multimedia presentations rely extensively on text content. Text can be used for incidental labels, or as subtitles or captions that accompany other media objects. In a multimedia document, text content is not only constrained by the need to support presentation styles and layout, it is also constrained by the temporal context of the presentation. This involves intra-text and extra-text timing synchronization with other media objects. This paper describes a new timed-text representation language that is intended to be embedded in a non-text host language. Our format, which we call aText (for the Ambulant Text Format), balances the need for text styling with the requirement for an efficient representation that can be easily parsed and scheduled at runtime. aText, which can also be streamed, is defined as an embeddable text format for use within declarative XML languages. The paper presents a discussion of the requirements for the format, a description of the format and a comparison with other existing and emerging text formats. We also provide examples for aText when embedded within the SMIL and MLIF languages and discuss our implementation experiences of aText with the Ambulant Player

Envelope structure of deeply embedded young stellar objects in the Serpens Molecular Cloud

Aperture synthesis and single-dish (sub) millimeter molecular lines and continuum observations reveal in great detail the envelope structure of deeply embedded young stellar objects (SMM1, SMM2, SMM3, SMM4) in the densely star-forming Serpens Molecular Cloud. Resolved millimeter continuum emission constrains the density structure to a radial power law with index -2.0 +/- 0.5, and envelope masses of 8.7, 3.0, and 5.3 M_sol for SMM1, SMM3, and SMM4. The core SMM2 does not seem to have a central condensation and may not have formed a star yet. The molecular line observations can be described by the same envelope model, if an additional, small amount of warm (100 K) material is included. This probably corresponds to the inner few hundred AU of the envelope were the temperature is high. In the interferometer beam, the molecular lines reveal the inner regions of the envelopes, as well as interaction of the outflow with the surrounding envelope. Bright HCO+ and HCN emission outlines the cavities, while SiO and SO trace the direct impact of the outflow on ambient gas. Taken together, these observations provide a first comprehensive view of the physical and chemical structure of the envelopes of deeply embedded young stellar objects in a clustered environment on scales between 1000 and 10,000 AU.Comment: 46 pages, incl. 12 postscript figures, uses ApJ latex and psfig macro