996 research outputs found
Cooperation, collective action, and the archeology of large-scale societies
Archeologists investigating the emergence of large-scale societies in the past have renewed interest in examining the dynamics of cooperation as a means of understanding societal change and organizational variability within human groups over time. Unlike earlier approaches to these issues, which used models designated voluntaristic or managerial, contemporary research articulates more explicitly with frameworks for cooperation and collective action used in other fields, thereby facilitating empirical testing through better definition of the costs, benefits, and social mechanisms associated with success or failure in coordinated group action. Current scholarship is nevertheless bifurcated along lines of epistemology and scale, which is understandable but problematic for forging a broader, more transdisciplinary field of cooperation studies. Here, we point to some areas of potential overlap by reviewing archeological research that places the dynamics of social cooperation and competition in the foreground of the emergence of large-scale societies, which we define as those having larger populations, greater concentrations of political power, and higher degrees of social inequality. We focus on key issues involving the communal-resource management of subsistence and other economic goods, as well as the revenue flows that undergird political institutions. Drawing on archeological cases from across the globe, with greater detail from our area of expertise in Mesoamerica, we offer suggestions for strengthening analytical methods and generating more transdisciplinary research programs that address human societies across scalar and temporal spectra
The Ontology of Intentional Agency in Light of Neurobiological Determinism: Philosophy Meets Folk Psychology
The moot point of the Western philosophical rhetoric about free will
consists in examining whether the claim of authorship to intentional, deliberative
actions fits into or is undermined by a one-way causal framework of determinism.
Philosophers who think that reconciliation between the two is possible are known as
metaphysical compatibilists. However, there are philosophers populating the other
end of the spectrum, known as the metaphysical libertarians, who maintain that claim
to intentional agency cannot be sustained unless it is assumed that indeterministic
causal processes pervade the action-implementation apparatus employed by the agent.
The metaphysical libertarians differ among themselves on the question of whether the
indeterministic causal relation exists between the series of intentional states and
processes, both conscious and unconscious, and the action, making claim for what has
come to be known as the event-causal view, or between the agent and the action,
arguing that a sort of agent causation is at work. In this paper, I have tried to propose
that certain features of both event-causal and agent-causal libertarian views need to be
combined in order to provide a more defendable compatibilist account accommodating
deliberative actions with deterministic causation. The ââagent-executed-eventcausal
libertarianismââ, the account of agency I have tried to develop here, integrates
certain plausible features of the two competing accounts of libertarianism turning
them into a consistent whole. I hope to show in the process that the integration of these
two variants of libertarianism does not challenge what some accounts of metaphysical
compatibilism proposeâthat there exists a broader deterministic relation between the
web of mental and extra-mental components constituting the agentâs dispositional
systemâthe agentâs beliefs, desires, short-term and long-term goals based on them,
the acquired social, cultural and religious beliefs, the general and immediate and
situational environment in which the agent is placed, etc. on the one hand and the
decisions she makes over her lifetime on the basis of these factors. While in the
ââIntroductionââ the philosophically assumed anomaly between deterministic causation
and the intentional act of deciding has been briefly surveyed, the second section is
devoted to the task of bridging the gap between compatibilism and libertarianism. The
next section of the paper turns to an analysis of folk-psychological concepts and
intuitions about the effects of neurochemical processes and prior mental events on the
freedom of making choices. How philosophical insights can be beneficially informed
by taking into consideration folk-psychological intuitions has also been discussed,
thus setting up the background for such analysis. It has been suggested in the end that
support for the proposed theory of intentional agency can be found in the folk-psychological intuitions, when they are taken in the right perspective
Do echo-enhanced needles improve time to cannulate in a model of short-axis ultrasound-guided vascular access for a group of mostly inexperienced ultrasound users?
Jupiter's XâRay and UV Dark Polar Region
We present 14 simultaneous Chandra X-ray Observatory (CXO)-Hubble Space Telescope (HST) observations of Jupiter's Northern X-ray and ultraviolet (UV) aurorae from 2016 to 2019. Despite the variety of dynamic UV and X-ray auroral structures, one region is conspicuous by its persistent absence of emission: the dark polar region (DPR). Previous HST observations have shown that very little UV emission is produced by the DPR. We find that the DPR also produces very few X-ray photons. For all 14 observations, the low level of X-ray emission from the DPR is consistent (within 2-standard deviations) with scattered solar emission and/or photons spread by Chandra's Point Spread Function from known X-ray-bright regions. We therefore conclude that for these 14 observations the DPR produced no statistically significant detectable X-ray signature
Hot new directions for quasi-Monte Carlo research in step with applications
This article provides an overview of some interfaces between the theory of
quasi-Monte Carlo (QMC) methods and applications. We summarize three QMC
theoretical settings: first order QMC methods in the unit cube and in
, and higher order QMC methods in the unit cube. One important
feature is that their error bounds can be independent of the dimension
under appropriate conditions on the function spaces. Another important feature
is that good parameters for these QMC methods can be obtained by fast efficient
algorithms even when is large. We outline three different applications and
explain how they can tap into the different QMC theory. We also discuss three
cost saving strategies that can be combined with QMC in these applications.
Many of these recent QMC theory and methods are developed not in isolation, but
in close connection with applications
New frontiers of managerial training: the LiVES project
The evolution of the Internet allowed the Web to become, among the different media, the most global, inter-active and dynamic medium to share information. Therefore, in the last decades, e-Learning has been widely used not only in the academic community, but also in the business sector. Within this context, thanks to their own competences, people can develop specific characteristics which may provide a competitive advantage for their organizations. The development and use of new technologies for the creation of three-dimensional (3D) Virtual Worlds set new challenges and enlarge the very idea of âlearning environmentâ. This paper aims at inves-tigating the characteristics of training activities directed at the managerial class, in such a way as to increase their efficacy; it also analyses how the use of specific innovative technologies may be an effective solution.The evolution of the Internet allowed the Web to become, among the different media, the most global, inter-active and dynamic medium to share information. Therefore, in the last decades, e-Learning has been widely used not only in the academic community, but also in the business sector. Within this context, thanks to their own competences, people can develop specific characteristics which may provide a competitive advantage for their organizations. The development and use of new technologies for the creation of three-dimensional (3D) Virtual Worlds set new challenges and enlarge the very idea of âlearning environmentâ. This paper aims at inves-tigating the characteristics of training activities directed at the managerial class, in such a way as to increase their efficacy; it also analyses how the use of specific innovative technologies may be an effective solution.Monograph's chapter
Evaluation of Two Methods to Estimate and Monitor Bird Populations
Background: Effective management depends upon accurately estimating trends in abundance of bird populations over time, and in some cases estimating abundance. Two population estimation methods, double observer (DO) and double sampling (DS), have been advocated for avian population studies and the relative merits and short-comings of these methods remain an area of debate. Methodology/Principal Findings: We used simulations to evaluate the performances of these two population estimation methods under a range of realistic scenarios. For three hypothetical populations with different levels of clustering, we generated DO and DS population size estimates for a range of detection probabilities and survey proportions. Population estimates for both methods were centered on the true population size for all levels of population clustering and survey proportions when detection probabilities were greater than 20%. The DO method underestimated the population at detection probabilities less than 30 % whereas the DS method remained essentially unbiased. The coverage probability of 95 % confidence intervals for population estimates was slightly less than the nominal level for the DS method but was substantially below the nominal level for the DO method at high detection probabilities. Differences in observer detection probabilities did not affect the accuracy and precision of population estimates of the DO method. Population estimates for the DS method remained unbiased as the proportion of units intensively surveyed changed, but the variance of th
The leadership component of Kellyâs Mobilisation Theory : contribution, tensions, limitations and further development
This reassessment of Kellyâs analysis of the relationship of activist leadership to collective action within the overall jigsaw of mobilisation theory draws on social movement literature, studies by industrial relations scholars utilising aspects of Kellyâs approach â including this authorâs own work â and related research on union leadership within collective mobilisation. In the process, it identifies and celebrates how Kellyâs work, whilst contributing a distinct and substantive actor-related approach, recognised that leadership is one ingredient amongst other factors, including important structural opportunities and constraints. It considers three potential ambiguities/tensions within Kellyâs conceptualisation of leadership related to the social construction of workersâ interests, spontaneity of workersâ action and the âleader/followerâ interplay. The review also identifies two important limitations, related to the union member/bureaucracy dynamic and the role of left-wing political leadership, and concludes by signalling different forms of leadership relationships on which further refinement and development would be fruitful
A new resorbable device for ligation of blood vessels - A pilot study
<p>Abstract</p> <p>Background</p> <p>During surgery, controlled haemostasis to prevent blood loss is vital for a successful outcome. It can be difficult to ligate vessels located deep in the abdomen. A device that is easy to use and enables secure ligatures could be beneficial. Cable ties made of nylon have been used for ligation but the non-resorbable material caused tissue reactions. The objective of this study was to use a resorbable material to construct a device with a self-locking mechanism and to test its mechanical strength and ligation efficiency.</p> <p>Methods</p> <p>The device was manufactured by injection moulding of polydioxanone, a resorbable polymer used for suture materials. Polydioxanone with inherent viscosities of 1.9 dL/g and 1.3 dL/g were tested. The device consisted of a perforated flexible band which could be pulled through a case with a locking mechanism. After a first version of the device had been tested, some improvements were made. The locking case was downsized, corners were rounded off, the band was made thicker and the mould was redesigned to produce longer devices. Tensile tests were performed with the second version.</p> <p>The first version of the device was used to ligate the ovarian pedicle in a euthanized dog and to test echogenicity of the device with ultrasound. Compression of vessels of the ovarian pedicle was examined by histology. Both versions of the device were tested for haemostasis of and tissue grip on renal arteries in six anaesthetised pigs.</p> <p>Results</p> <p>The tensile strength of the flexible band of the devices with inherent viscosity of 1.9 dL/g was 50.1 ± 5.5 N (range 35.2-62.9 N, <it>n </it>= 11) and the devices with inherent viscosity of 1.3 dL/g had a tensile strength of 39.8 ± 8.1 N (range 18.6-54.2 N, <it>n </it>= 11). Injection moulding of the polymer with lower inherent viscosity resulted in a longer flow distance.</p> <p>Both versions of the device had an effective tissue grip and complete haemostasis of renal arteries was verified. The device attached to the ovarian pedicle could be seen with ultrasound, and vessel compression and occlusion were verified by histology.</p> <p>Conclusions</p> <p>Tests of functionality of the device showed complete haemostasis and good tissue grip. Devices with a band of sufficient length were easily applied and tightened in tissue.</p
Radio Emission from Ultra-Cool Dwarfs
The 2001 discovery of radio emission from ultra-cool dwarfs (UCDs), the very
low-mass stars and brown dwarfs with spectral types of ~M7 and later, revealed
that these objects can generate and dissipate powerful magnetic fields. Radio
observations provide unparalleled insight into UCD magnetism: detections extend
to brown dwarfs with temperatures <1000 K, where no other observational probes
are effective. The data reveal that UCDs can generate strong (kG) fields,
sometimes with a stable dipolar structure; that they can produce and retain
nonthermal plasmas with electron acceleration extending to MeV energies; and
that they can drive auroral current systems resulting in significant
atmospheric energy deposition and powerful, coherent radio bursts. Still to be
understood are the underlying dynamo processes, the precise means by which
particles are accelerated around these objects, the observed diversity of
magnetic phenomenologies, and how all of these factors change as the mass of
the central object approaches that of Jupiter. The answers to these questions
are doubly important because UCDs are both potential exoplanet hosts, as in the
TRAPPIST-1 system, and analogues of extrasolar giant planets themselves.Comment: 19 pages; submitted chapter to the Handbook of Exoplanets, eds. Hans
J. Deeg and Juan Antonio Belmonte (Springer-Verlag
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