The use of microencapsulated feeds to replace live food organisms in shrimp hatcheries

Abstract only.An adequate supply of hatchery produced shrimp fry is the major constraint to the intensification and growth of shrimp culture practices. If even 20% of the more than 500,000 ha of the world's existing tropical and sub-tropical brackishwater ponds were to stock at the relatively low density of 50,000 fry/ha/year, it would take thousands of new hatcheries to produce the 25 billion fry required. The availability of artificially produced diets to replace cultured live food organisms would alleviate many of the problems currently limiting shrimp hatchery production by: (i) reducing the level of technical skill required to operate a hatchery; (ii) assuring a reliable supply of a nutritionally balanced larval feed; (iii) reducing sources of contamination and larval disease; and (iv) simplifying hatchery design and capital cost requirements, thereby facilitating small scale hatchery development. Aquatic farms has been working with the Mars Microencapsulation Research Group (MMRG) to develop techniques for adapting current shrimp hatchery technology and design so that MMRG feeds can be used in existing hatcheries as a live feed replacement. Feeding trials have been conducted in commercial hatcheries in Hawaii, Malaysia and Thailand. The results of these trials and the techniques employed are discussed. Growth and survival of larvae fed microencapsulated diets as total or partial replacement of live foods was comparable to larvae cultured in control tanks using the standard operating procedures of the hatchery in which the trials were conducted. In trials to date, larval survival from nauplii to postlarvae has been as high as 70%

What Are Kinship Terminologies, and Why Do We Care? A Computational Approach to Analyzing Symbolic Domains

Kinship is a fundamental feature and basis of human societies. We describe a set of computational tools and services, the Kinship Algebra Modeler, and the logic that underlies these. These were developed to improve how we understand both the fundamental facts of kinship, and how people use kinship as a resource in their lives. Mathematical formalism applied to cultural concepts is more than an exercise in model building, as it provides a way to represent and explore logical consistency and implications. The logic underlying kinship is explored here through the kin term computations made by users of a terminology when computing the kinship relation one person has to another by referring to a third person for whom each has a kin term relationship. Kinship Algebra Modeler provides a set of tools, services and an architecture to explore kinship terminologies and their properties in an accessible manner

Stochastic Capital Depreciation and the Comovement of Hours and Productivity

In this article, we demonstrate that a small degree of stochastic variation in the depreciation rate of capital can greatly reduce the comovement between hours worked and labor productivity in a neoclassical growth model. The depreciation rate is modeled as a Markov process to place a strict upper bound and to ensure that variation and not the level of the rate is driving the result. Markov switching implies nonlinear decision rules in the dynamic stochastic general equilibrium model (DSGE). Our contribution to DSGE solution methodologies in the presence of Markov switching is to apply Judd's (1998) projection method to nonlinear decision rules. This approach allows for nonlinear decision rules in a richer set of models with many more state variables than can be solved with grid based approximations. The results presented here suggest that Markov switching parameters offer a powerfull extension to DSGE models.

Organizational Turbulence, Trouble and Trauma: Theorizing the Collapse of a Mental Health Setting

Turbulence is usually considered a negative property of an organization’s environment. Yet turbulence is also a feature of an organization’s internal dynamics and may be useful for productivity. This article argues that interactions between the formal and informal management of trouble produce relational turbulence that may mobilize resources and collective action, or conversely lead to dysfunction and crisis. The author links relational psychoanalytic theory with social constructionist perspectives in exploring intersubjective dynamics of trouble and its repercussions of turbulence. Based on a longitudinal interorganizational ethnography, an atypical mental healthcare organization is described – a democratic therapeutic community – in which turbulence plays a central function, but in two very different ways. In a restorative mode, turbulence generates formative spaces that are creative and have a regulating function, useful for organizational productivity. Conversely, a perverse mode is destructive and may produce intractable perverse spaces, leading to organizational dysfunction, crisis and even collapse. This is theorized by extending the psychoanalytic concept of liminal, transitional space. In contrast to the notion of transitional space as a safe, protective area, the author develops a model of distinct formative and perverse spaces created by relational turbulence in organizations. In human service organizations, where the generation, trading and management of trouble are inherent in an organization’s internal dynamics, turbulence may be a valuable resource, but one that, in the perverse mode, can be immensely destructive

Stochastic capital depreciation and the comovement of hours and productivity

An unresolved question concerning stochastic depreciation shocks is whether they have to be unrealistically large to have any useful role in a dynamic general equilibrium model economy, as Ambler and Paquet (1994) first suggested. We first consider implied depreciation rates from sectoral data from the Bureau of Economic Analysis. These depreciation rates vary across time solely due to compositional changes within each sector. Hence, they tend to understate the range of fluctuation that would hold if the economic shelf life of capital varied endogenously as in Cooley, Greenwood and Yorukoglu (1997). We find, however, that if depreciation rates follow a Markov switching process, a low variance of the depreciation rate can generate the low correlation between hours worked and productivity in a simple model economy. White noise and autoregressive depreciation shocks, in contrast, require a counterfactually large variance in the depreciation rate to reduce the hours-productivity correlation. We also illustrate the level effects implied by nonlinear decision rules in simulations of dynamic general equilibrium models that include Markov switching parameters. Linear decision rules, in contrast, imply certainty equivalence and ignore the aversion that agents have to the skewed shock distributions that characterize Markov switching.Econometric models ; Productivity

New Technologies and Mixed-Use Convergence How Humans and Algorithms are Adapting to Each Other

Human experience with technology has shifted from technological contexts requiring occasional intervention by a fraction of people mostly in command of technologies, to technological contexts that require constant ongoing participation from most people to complete tasks. We examine the current state of `mixed-use' new technologies integration with legacy systems, and whether the human assistance required to complete tasks and processes could function as a training ground for future smart systems, or whether increasing `co-dependence with' or `training of' algorithmic systems, enhancing task completion and inadvertently educating systems in human behaviour and intelligence, will simply subsume people into the algorithmic landscape. As the Internet of Things (IoT) arises in conjunction with advancing robotics and drone technology, semi and fully automated algorithmic systems are being developed that intersect with human experience in new and heterogeneous ways. Many new technologies are not yet flexible enough to support the choices people require in their daily lives, due to limitations in the algorithmic `logics' used that restrict options to predetermined pathways conceived of by programmers. This greatly limits human agency, and presently the potential to overcome problems that arise in processes. In this mixed-use period, we have the opportunity to develop new ways to address ethical guidance as knowledge that machines can learn. We explore promoting embedding of ethically-based principles into automated contexts through: (1) developing mutually agreed automated external ethical review systems (human or otherwise) that evaluate conformance across multiple ethical codes and provide feedback to designers, agents, and users on the distribution of conformance; (2) focusing on review systems to drive distributed development of embedded ethical principles in individual services by responding to this feedback to develop ongoing correction through dynamic adaption or incremental releases; and (3) using multi-agent simulation tools to forecast scenarios in real time

Exploring Cooperation with Social Machines

As humans become more and more immersed in a networked world of connected and mobile devices, cooperation and sociability to achieve valued outcomes within geographic locales appears to be waning in favour of extended personal networks and interaction using semi-automated agents to support communications, transportation and other services. From a messaging structure that is complex, multiplexed and much of the time asynchronous, conditions emerge that disrupt symmetry of information exchange. People thus encounter circumstances that seem unpredictable given the information available to them, resulting in limited or failed cooperation and consequent quality of outcomes. We explore the role of Social Machines to support, change, and enhance human cooperation within a blended reality context

SIMULATED IN-TRANSIT VIBRATION DAMAGE TO FRESH MARKET RASPBERRIES

Agribusiness,