1,470 research outputs found

    Activities for Teaching Letter Identification

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    The focus of this project was to compile and design research based letter identification activities. Emphasis was placed on the highly confusable letters b-d , p-q , and n-u . The activities were for use in the first grade curriculum. Learning objectives were stated for each activity. The activities, utilizing a variety of materials, were chosen and designed for hands-on application. Needed materials were listed, directions and patterns for construction were included, directions for use were provided, and classroom management was suggested. Use of the activities was divided into three parts: whole group introduction, guided practice, and small group activities

    FTS-based face milling of micro structures

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    This article presents a technical concept and machining possibilities for milling of micro structures with a fast tool servo (FTS). The tool is capable of tool tip displacements with a variable frequency up to 4000 Hz and an amplitude up to 30 μm. The control system of the actuator is linked to the angular spindle position, allowing to freely manipulate the excitation signal. Combining this tool system with a single tooth face milling head, micro structures on flat surfaces can be generated on conventional milling centers. Selected micro structures are machined and evaluated in terms of precision and surface quality.DFG/CRC/65

    Slow swimming, fast strikes: effects of feeding behavior on scaling of anaerobic metabolism in epipelagic squid

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    Many pelagic fishes engage prey at high speeds supported by high metabolic rates and anaerobic metabolic capacity. Epipelagic squids are reported to have among the highest metabolic rates in the oceans as a result of demanding foraging strategies and the use of jet propulsion, which is inherently inefficient. This study examined enzymatic proxies of anaerobic metabolism in two species of pelagic squid, Dosidicus gigas and Doryteuthis pealeii (Lesueur 1821), over a size range of six orders of magnitude. We hypothesized that activity of the anaerobically poised enzymes would be high and increase with size as in ecologically similar fishes. In contrast, we demonstrate that anaerobic metabolic capacity in these organisms scales negatively with body mass. We explored several cephalopod-specific traits, such as the use of tentacles to capture prey, body morphology and reduced relative prey size of adult squids, that may create a diminished reliance on anaerobically fueled burst activity during prey capture in large animals

    The thermal stress response to diel vertical migration in the hyperiid amphipod Phronima sedentaria

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    The hyperiid amphipod Phronima sedentaria experiences a temperature change of 15 °C during diel migration in the Eastern Tropical North Pacific (ETNP) from 8–10 °C at depth to 25–27 °C at night in the surface waters. The aim of this study was to determine if the natural temperature gradient experienced by P. sedentaria results in a thermal stress response. Individuals were initially exposed to their night time temperatures (23 °C) and subsequently subjected to temperatures within and above the range they typically experience. In the Eastern Tropical North Pacific P. sedentaria tolerates its normal night-time temperature (~ 23 °C), but only for the duration of its stay there (~ 9 h). Longer exposures (24 h) result in elevated heat shock protein (hsp) expression. 29 °C results in hsp expression, increased lactate production and 50% mortality at all exposure durations. This represents an upper critical temperature. Understanding the adaptations of pelagic amphipods to their current environment will help predict the physiological impacts of global warming for amphipods and their predators

    Activities on the HE-Linac DTL cavity RF-design

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    The Collaboration of Human Resource Management and Line Management–An International Comparison

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    The extant research advocates for the strategic integration of human resource management (HRM) in managerial decision making to foster firm performance. However, the empirical evidence of a stronger strategic integration of HRM is still limited, especially in terms of strategic guidelines such as a human resource (HR) strategy and international comparative matters. Drawing on responses from 588 German and US-based organizations and related to the new institutionalism theory, this study examines whether a HRM partnership (i.e., sharing responsibilities between HRM and line management) that represents a particular form of strategic integration of HRM is beneficial for organizations. In particular, we find international differences as a more pronounced HRM partnership increases employee turnover in the USA, whereas no significant changes are encountered in Germany. We further demonstrate that organizations located in the USA are more likely to have a formal HR strategy compared to those in Germany. However, this study can neither provide support for the direct effect of a HRM partnership on employee turnover nor of a moderation of this relationship through the HR strategy

    Energetic Plasticity Underlies a Variable Response to Ocean Acidification in the Pteropod, \u3cem\u3eLimacina helicina antarctica\u3c/em\u3e

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    Ocean acidification, caused by elevated seawater carbon dioxide levels, may have a deleterious impact on energetic processes in animals. Here we show that high PCO2 can suppress metabolism, measured as oxygen consumption, in the pteropod, L. helicina forma antarctica, by ~20%. The rates measured at 180–380 µatm (MO2 = 1.25 M−0.25, p = 0.007) were significantly higher (ANCOVA, p = 0.004) than those measured at elevated target CO2 levels in 2007 (789–1000 µatm, = 0.78 M−0.32, p = 0.0008; Fig. 1). However, we further demonstrate metabolic plasticity in response to regional phytoplankton concentration and that the response to CO2 is dependent on the baseline level of metabolism. We hypothesize that reduced regional Chl a levels in 2008 suppressed metabolism and masked the effect of ocean acidification. This effect of food limitation was not, we postulate, merely a result of gut clearance and specific dynamic action, but rather represents a sustained metabolic response to regional conditions. Thus, pteropod populations may be compromised by climate change, both directly via CO2-induced metabolic suppression, and indirectly via quantitative and qualitative changes to the phytoplankton community. Without the context provided by long-term observations (four seasons) and a multi-faceted laboratory analysis of the parameters affecting energetics, the complex response of polar pteropods to ocean acidification may be masked or misinterpreted

    Flight of the Vampire: Ontogenetic Gait-Transition in \u3cem\u3eVampyroteuthis Infernalis\u3c/em\u3e (Cephalopoda: Vampyromorpha)

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    Vampyroteuthis infernalis is a cosmopolitan cephalopod that lives in the oxygen minimum layer between 600 and 800 m depth. Morphometric and physiological studies have indicated that V. infernalis has little capacity for jet propulsion and has the lowest metabolic rate ever measured for a cephalopod. Because fin swimming is inherently more efficient than jet propulsion, some of the reduction in energy usage relative to other cephalopods may result from the use of fins as the primary means of propulsion. V. infernalis undergoes a rapid metamorphosis which consists of changes in the position, size and shape of the fins. This suggests that there are changes in the selective factors affecting locomotion through ontogeny. The present study describes these changes in relation to models for underwater ‘flight’. Citrate synthase (CS) and octopine dehydrogenase (ODH) activities, indicative of aerobic and anaerobic metabolism, respectively, were measured in fin, mantle and arm tissue across a range of body size of four orders of magnitude. The low enzymatic activities in both posterior and anterior fin tissue and the relatively high activity in mantle muscle prior to metamorphosis indicate that jet propulsion using mantle contraction is the primary means of propulsion in juvenile V. infernalis. The increase in CS activity with size after metamorphosis suggests an increased use of the fins for lift-based propulsion. Fin swimming appears to be the primary means of propulsion at all adult sizes. The negative allometry of CS activity in mantle and arm muscle is consistent with the scaling of oxygen consumption previously measured for V. infernalis and with the scaling of aerobic metabolism observed in most animals. The unusual positive allometry of fin muscle CS activity suggests that the use of fins is either relatively more important or more costly in larger animals. Positive scaling of ODH activity in all tissues suggests that fin propulsion, jet propulsion and medusoid ‘bell-swimming’ are all important for burst escape responses. Enzyme activities in Cirrothauma murrayi are consistent with finswimming observed from submersibles, while those in Opisthoteuthis californiana suggest a strong reliance on medusoid swimming using the arms. The transition from jet propulsion to paired-fin ‘flight’ with increasing body size in Vampyroteuthis infernalis appears functionally to be an ontogenetic ‘gait-transition’

    Status of the cold model for the HE-Linac cavities

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