1,656 research outputs found
Surface conditions of the Orgueil meteorite parent body as indicated by mineral associations
Three periods of mineral formation from study of Orgueil meteorit
A radio jet drives a molecular and atomic gas outflow in multiple regions within one square kiloparsec of the nucleus of the nearby galaxy IC5063
We analyzed near-infrared data of the nearby galaxy IC5063 taken with the
Very Large Telescope SINFONI instrument. IC5063 is an elliptical galaxy that
has a radio jet nearly aligned with the major axis of a gas disk in its center.
The data reveal multiple signatures of molecular and atomic gas that has been
kinematically distorted by the passage of the jet plasma or cocoon within an
area of ~1 kpc^2. Concrete evidence that the interaction of the jet with the
gas causes the gas to accelerate comes from the detection of outflows in four
different regions along the jet trail: near the two radio lobes, between the
radio emission tip and the optical narrow-line-region cone, and at a region
with diffuse 17.8 GHz emission midway between the nucleus and the north radio
lobe. The outflow in the latter region is biconical, centered 240 pc away from
the nucleus, and oriented perpendicularly to the jet trail. The diffuse
emission that is observed as a result of the gas entrainment or scattering
unfolds around the trail and away from the nucleus with increasing velocity. It
overall extends for >700 pc parallel and perpendicular to the trail. Near the
outflow starting points, the gas has a velocity excess of 600 km/s to 1200 km/s
with respect to ordered motions, as seen in [FeII], Pa alpha, or H2 lines. High
H2 (1-0) S(3)/S(1) flux ratios indicate non-thermal excitation of gas in the
diffuse outflow.Comment: Accepted for publication in Ap
Prediction and explanation in the multiverse
Probabilities in the multiverse can be calculated by assuming that we are
typical representatives in a given reference class. But is this class well
defined? What should be included in the ensemble in which we are supposed to be
typical? There is a widespread belief that this question is inherently vague,
and that there are various possible choices for the types of reference objects
which should be counted in. Here we argue that the ``ideal'' reference class
(for the purpose of making predictions) can be defined unambiguously in a
rather precise way, as the set of all observers with identical information
content. When the observers in a given class perform an experiment, the class
branches into subclasses who learn different information from the outcome of
that experiment. The probabilities for the different outcomes are defined as
the relative numbers of observers in each subclass. For practical purposes,
wider reference classes can be used, where we trace over all information which
is uncorrelated to the outcome of the experiment, or whose correlation with it
is beyond our current understanding. We argue that, once we have gathered all
practically available evidence, the optimal strategy for making predictions is
to consider ourselves typical in any reference class we belong to, unless we
have evidence to the contrary. In the latter case, the class must be
correspondingly narrowed.Comment: Minor clarifications adde
Latitude, temperature, and habitat complexity predict predation pressure in eelgrass beds across the Northern Hemisphere
Latitudinal gradients in species interactions are widely cited as potential causes or consequences of global patterns of biodiversity. However, mechanistic studies documenting changes in interactions across broad geographic ranges are limited. We surveyed predation intensity on common prey (live amphipods and gastropods) in communities of eelgrass (Zostera marina) at 48 sites across its Northern Hemisphere range, encompassing over 37 degrees of latitude and four continental coastlines. Predation on amphipods declined with latitude on all coasts but declined more strongly along western ocean margins where temperature gradients are steeper. Whereas insitu water temperature at the time of the experiments was uncorrelated with predation, mean annual temperature strongly positively predicted predation, suggesting a more complex mechanism than simply increased metabolic activity at the time of predation. This large-scale biogeographic pattern was modified by local habitat characteristics; predation declined with higher shoot density both among and within sites. Predation rates on gastropods, by contrast, were uniformly low and varied little among sites. The high replication and geographic extent of our study not only provides additional evidence to support biogeographic variation in predation intensity, but also insight into the mechanisms that relate temperature and biogeographic gradients in species interactions
Characteristics of Effective GSS Facilitators
As businesses increase their use of groups to solve problems, the importance of strong group facilitation skills has increased. This paper investigates the characteristics of high-performing group facilitators versus low-performing group facilitators. The characteristics investigated represent two broad areas of interest: general facilitator background and skills possessed by the facilitator. The facilitator background factors that proved to be good predictors of high performance included: overall experience and number of computer-supported meeting facilitated. The skills possessed by high performers included: plans and designs meetings, demonstrates flexibility, and listens to, clarifies, and integrates information. The analysis provides a rule for accurately predicting whether a facilitator is a high-performer or a low-performer more than 77% of the time
Part I of Finnish Agility Dog Survey: Training and Management of Competition-Level Agility Dogs
Simple Summary Information on training, competition, and management of agility dogs is sparse. To decrease this knowledge gap, Finnish owners and handlers of competition-level agility dogs completed an online questionnaire to describe the agility routines of their dog during one injury-free year. Additional information on competition routines was retrieved from the national competition results database. Typically, competition-level agility dogs trained agility once or twice a week and competed two runs a month. The median total weekly training time was 18 min. Usual speed over the competition course was 4.3 m/s. Artificial turf, with or without filling, and dirt surfaces are used most often. Dogs are warmed up before and cooled down after agility performance. Most dogs visit a massage therapist, physiotherapist, osteopath or other professionals of musculoskeletal care at least every three months. Many dogs undergo conditioning exercises, although often less often than every two weeks. Additionally, agility dogs are walked for a total of 1.5 h a day. Dogs competing at the highest levels competed more but trained less than dogs at lower levels. This is the first investigation of agility-related routines in competing agility dogs. Knowledge regarding training, competition, and management routines of agility dogs is lacking. Through a retrospective online questionnaire, Finnish owners and handlers of 745 competition-level agility dogs provided information on training routines and management of these dogs during one year free of agility-related injuries. Competition routines were collected from the national competition results database. Most dogs trained agility 1-2 times a week, with a median active training time of 18 min a week. Dogs competed in a median of 2.1 runs per month at a speed of 4.3 m/s. Common field surfaces were different types of artificial turfs and dirt surface. Warm-up and cool-down were established routines, and 62% of dogs received regular musculoskeletal care. Moreover, 77% of dogs underwent conditioning exercises, but their frequency was often low. Additionally, dogs were walked for a median of 1.5 h daily. Pearson's chi-squared and Kruskal-Wallis tests were used to evaluate the association between a dog's competition level and training and competition variables. A dog's competition level was associated with competition (p < 0.001) and training frequency (p < 0.001); dogs at higher levels compete more but train less than dogs at lower levels. This study provides information on training, competition, and management routines of competing agility dogs
AAAI: an Argument Against Artificial Intelligence
The ethical concerns regarding the successful development of an Artificial Intelligence have received a lot of attention lately. The idea is that even if we have good reason to believe that it is very unlikely, the mere possibility of an AI causing extreme human suffering is important enough to warrant serious consideration. Others look at this problem from the opposite perspective, namely that of the AI itself. Here the idea is that even if we have good reason to believe that it is very unlikely, the mere possibility of humanity causing extreme suffering to an AI is important enough to warrant serious consideration. This paper starts from the observation that both concerns rely on problematic philosophical assumptions. Rather than tackling these assumptions directly, it proceeds to present an argument that if one takes these assumptions seriously, then one has a moral obligation to advocate for a ban on the development of a conscious AI
An Infrared Divergence Problem in the cosmological measure theory and the anthropic reasoning
An anthropic principle has made it possible to answer the difficult question
of why the observable value of cosmological constant (
GeV) is so disconcertingly tiny compared to predicted value of vacuum
energy density GeV. Unfortunately, there is a
darker side to this argument, as it consequently leads to another absurd
prediction: that the probability to observe the value for randomly
selected observer exactly equals to 1. We'll call this controversy an infrared
divergence problem. It is shown that the IRD prediction can be avoided with the
help of a Linde-Vanchurin {\em singular runaway measure} coupled with the
calculation of relative Bayesian probabilities by the means of the {\em
doomsday argument}. Moreover, it is shown that while the IRD problem occurs for
the {\em prediction stage} of value of , it disappears at the {\em
explanatory stage} when has already been measured by the observer.Comment: 9 pages, RevTe
The quantum cryptographic switch
We illustrate using a quantum system the principle of a cryptographic switch,
in which a third party (Charlie) can control to a continuously varying degree
the amount of information the receiver (Bob) receives, after the sender (Alice)
has sent her information. Suppose Charlie transmits a Bell state to Alice and
Bob. Alice uses dense coding to transmit two bits to Bob. Only if the 2-bit
information corresponding to choice of Bell state is made available by Charlie
to Bob can the latter recover Alice's information. By varying the information
he gives, Charlie can continuously vary the information recovered by Bob. The
performance of the protocol subjected to the squeezed generalized amplitude
damping channel is considered. We also present a number of practical situations
where a cryptographic switch would be of use.Comment: 7 pages, 4 Figure
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