41 research outputs found
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Communication in Purposeful Human Activity Systems: The Role of Signs in Organizational Change Management
Communication in purposeful human activity systems plays a critical role in the design, management, and change management of these systems. However, its impact on and integrated nature in purposeful human activity systems is not well understood from a holistic viewpoint. In addition, a formal definition and methodology for identifying signs exhibited by purposeful human activity systems, the foundation of the communication system, has not been explored. Purposeful human activity system signs representative of meaning, behavior, structure, and process, indicate the current state of the system and offer a measure of success regarding the system’s pursuit of its purpose. As purposeful human activity systems exist for a purpose and actively pursue their purpose, identifying signs regarding the state of the system is critical to management and change efforts of the system. As current research on communication in organizations is largely focused on heuristic methods, the work presented in this document addresses the need for a more scientific and systemic approach to realizing and designing communication systems. This research can serve researchers and practitioners by presenting systemic methods and practices for managing change through the evaluation of purposeful human activity system signs that will enable the creation of impactful messages. These messages then can be used, among other purposes, to measure and improve successful communication in the design, realization, and management of purposeful human activity systems
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The Guess & Check: Evaluating the Usability and Effectiveness of a Primary Prevention Assessment Tool for Classroom Teachers
Schools are continually faced with the challenge of providing students with a comprehensive system of support. Previous research based on the practices and systems of Positive Behavior Intervention and Supports (PBIS) suggests that having effective primary prevention measures in place can help to reduce problem behavior before it occurs (Ingram, Lewis-Palmer, & Sugai, 2005; Sugai, Lewis-Palmer, & Hagan-Burke, 1999). Without these preventative measures, low-level, high frequency behaviors can escalate causing strain on the teacher-student relationship and impacting the academic success of students. The current study seeks to assess the usability and effectiveness of the “Guess & Check,” a teacher-guided prevention assessment tool originally created by O’Keefe, Lewis-Palmer, and Sugai (2001). Teacher-generated hypotheses using the “Guess & Check” were compared to student researchers’ hypotheses, developed from functional behavior assessment interviews (FBAIs) and descriptive direct observations. Additionally, a withdrawal design was incorporated to compare pre-intervention student data (baseline) to post-intervention data (intervention) in order to evaluate the usefulness of the teacher-guided interventions using the “Guess & Check.
Sexual morph specialisation in a trioecious nematode balances opposing selective forces
The coexistence of different mating strategies, whereby a species can reproduce both by selfing and outcrossing, is an evolutionary enigma that has long intrigued biologists (Darwin, 1877). Theory predicts only two stable mating states : outcrossing with strong inbreeding depression or selfing with weak inbreeding depression. As these two mating strategies are subject to opposing selective forces, mixed breeding systems are thought to be a rare transitory state, yet they have been found to persist even after multiple speciation events. We hypothesise that if each mating strategy plays a distinctive role during the species life history, opposing selective pressures could be balanced, permitting the stable co-existence of selfing and outcrossing sexual morphs. In this scenario, we would expect each sexual morph to be specialised in their respective roles. Here we show, using a combination of behavioural, physiological and gene expression studies, that the selfing (hermaphrodite) and outcrossing (female) sexual morphs of the trioecious nematode Auanema freiburgensis have distinct adaptations optimised for their different roles during the life cycle. A. freiburgensis hermaphrodites are produced under stressful conditions, are specialised for dispersal to new habitat patches and exhibit metabolic and intestinal changes that enable them to meet the energetic cost of dispersal and reproduction. In contrast, A. freiburgensis females are produced in favourable conditions, facilitate rapid population growth and compensate for the lack of reproductive assurance by reallocating resources from intestinal development to robust mate-finding behaviour. The specialisation of each mating system for their role in the life cycle could balance opposing selective forces allowing the stable maintenance of both outcrossing and selfing mating systems in A. freiburgensis
Actin-dependent vacuolar occupancy of the cell determines auxin-induced growth repression
The cytoskeleton is an early attribute of cellular life and its main components are composed of conserved proteins (Fletcher and Mullins, 2010). The actin cytoskeleton has a direct impact on cell size control in animal cells (Fletcher and Mullins, 2010; Faix et al., 1996), but its mechanistic contribution to cellular growth in plants remains largely elusive. Here, we reveal a role of actin in cell size regulation in plants. The actin cytoskeleton shows proximity to vacuoles, and the phytohormone auxin not only controls the organisation of actin filaments, but also impacts on vacuolar morphogenesis in an actin-dependent manner.
Pharmacological and genetic interference with the actin-myosin system abolishes the auxin effect on vacuoles and thus disrupts its negative influence on cellular growth. SEM-based 3D nanometre resolution imaging of the vacuoles revealed that auxin controls the constriction and luminal size of the vacuole. We show that this actin-dependent mechanism controls the relative cellular occupancy of the vacuole, thus proposing an unanticipated mechanism for cytosol homeostasis during cellular growth
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Above-aircraft cirrus cloud and aerosol optical depth from hyperspectral irradiances measured by a total-diffuse radiometer
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Empirically derived parameterizations of the direct aerosol radiative effect based on ORACLES aircraft observations
In this paper, we use observations from the NASA ORACLES (ObseRvations of CLouds above Aerosols and their intEractionS) aircraft campaign to develop a framework by way of two parameterizations that establishes regionally representative relationships between aerosol-cloud properties and their radiative effects. These relationships rely on new spectral aerosol property retrievals of the single scattering albedo (SSA) and asymmetry parameter (ASY). The retrievals capture the natural variability of the study region as sampled, and both were found to be fairly narrowly constrained (SSA: 0.83 ± 0.03 in the mid-visible, 532 nm; ASY: 0.54 ± 0.06 at 532 nm). The spectral retrievals are well suited for calculating the direct aerosol radiative effect (DARE) since SSA and ASY are tied directly to the irradiance measured in the presence of aerosols – one of the inputs to the spectral DARE.
The framework allows for entire campaigns to be generalized into a set of parameterizations. For a range of solar zenith angles, it links the broadband DARE to the mid-visible aerosol optical depth (AOD) and the albedo (α) of the underlying scene (either clouds or clear sky) by way of the first parameterization: P(AOD, α). For ORACLES, the majority of the case-to-case variability of the broadband DARE is attributable to the dependence on the two driving parameters of P(AOD, α). A second, extended, parameterization PX(AOD, α, SSA) explains even more of the case-to-case variability by introducing the mid-visible SSA as a third parameter. These parameterizations establish a direct link from two or three mid-visible (narrowband) parameters to the broadband DARE, implicitly accounting for the underlying spectral dependencies of its drivers. They circumvent some of the assumptions when calculating DARE from satellite products or in a modeling context. For example, the DARE dependence on aerosol microphysical properties is not explicit in P or PX because the asymmetry parameter varies too little from case to case to translate into appreciable DARE variability. While these particular DARE parameterizations only represent the ORACLES data, they raise the prospect of generalizing the framework to other regions.
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Aerobic submerged fermentation by acetic acid bacteria for vinegar production: process and biotechnological aspects
Strictly aerobic acetic acid bacteria (AAB) have a long history of use in fermentation processes, and the conversion of ethanol to acetic acid for the production of vinegar is the most well-known application.
At the industrial scale, vinegar is mainly produced by submerged fermentation, which refers to an aerobic process in which the ethanol in beverages such as spirits, wine or cider is oxidized to acetic acid by AAB. Submerged fermentation requires robust AAB strains that are able to oxidize ethanol under selective conditions to produce high-titer acetic acid. Currently submerged fermentation is conducted by unselected AAB cultures, which are derived from previous acetification stocks and maintained by repeated cultivation cycles.
In this work, submerged fermentation for vinegar production is discussed with regard to advances in process optimization and parameters (oxygen availability, acetic acid content and temperature) that influence AAB activity. Furthermore, the potential impact arising from the use of selected AAB is described.
Overcoming the acetification constraints is a main goal in order to facilitate innovation in submerged fermentation and to create new industry-challenging perspectives
Acetic Acid Bacteria: Physiology and Carbon Sources Oxidation
Acetic acid bacteria (AAB) are obligately aerobic bacteria within the family Acetobacteraceae, widespread in sugary, acidic and alcoholic niches. They are known for their ability to partially oxidise a variety of carbohydrates and to release the corresponding metabolites (aldehydes, ketones and organic acids) into the media. Since a long time they are used to perform specific oxidation reactions through processes called “oxidative fermentations”, especially in vinegar production. In the last decades physiology of AAB have been widely studied because of their role in food production, where they act as beneficial or spoiling organisms, and in biotechnological industry, where their oxidation machinery is exploited to produce a number of compounds such as l-ascorbic acid, dihydroxyacetone, gluconic acid and cellulose. The present review aims to provide an overview of AAB physiology focusing carbon sources oxidation and main products of their metabolism
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Above-cloud aerosol radiative effects based on ORACLES 2016 and ORACLES 2017 aircraft experiments
Determining the direct aerosol radiative effect (DARE) of absorbing aerosols above clouds from satellite observations alone is a challenging task, in part because the radiative signal of the aerosol layer is not easily untangled from that of the clouds below. In this study, we use aircraft measurements from the NASA ObseRvations of CLouds above Aerosols and their intEractionS (ORACLES) project in the southeastern Atlantic to derive it with as few assumptions as possible. This is accomplished by using spectral irradiance measurements (Solar Spectral Flux Radiometer, SSFR) and aerosol optical depth (AOD) retrievals (Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research, 4STAR) during vertical profiles (spirals) that minimize the albedo variability of the underlying cloud field – thus isolating aerosol radiative effects from those of the cloud field below. For two representative cases, we retrieve spectral aerosol single scattering albedo (SSA) and the asymmetry parameter (g) from these profile measurements and calculate DARE given the albedo range measured by SSFR on horizontal legs above clouds. For mid-visible wavelengths, we find SSA values from 0.80 to 0.85 and a significant spectral dependence of g. As the cloud albedo increases, the aerosol increasingly warms the column. The transition from a cooling to a warming top-of-aerosol radiative effect occurs at an albedo value (critical albedo) just above 0.2 in the mid-visible wavelength range. In a companion paper, we use the techniques introduced here to generalize our findings to all 2016 and 2017 measurements and parameterize aerosol radiative effects.</p
A Scoping Review of Study Skill Groups Implemented in Secondary and Postsecondary Schools
Purpose of this project is conduct a scoping literature review of study skill groups implemented in secondary and postsecondary settings