885 research outputs found
Conjunctors and their residual implicators: characterizations and construction methods
In many practical applications of fuzzy logic it seems clear that one needs more flexibility
in the choice of the conjunction: in particular, the associativity and the commutativity of
a conjunction may be removed. Motivated by these considerations, we present several classes
of conjunctors, i.e. binary operations on that are used to extend the boolean conjunction
from to , and characterize their respective residual implicators. We establish
hence a one-to-one correspondence between construction methods for conjunctors and construction
methods for residual implicators. Moreover, we introduce some construction methods directly in the class
of residual implicators, and, by using a deresiduation procedure, we obtain new conjunctors
Copulas constructed from horizontal sections
In analogy with the study of copulas whose diagonal sections have
been fixed, we study the set of copulas for which a horizontal section has been given. We first show that this set is not empty, by explicitly writing one such copula, which we call \textit{horizontal copula}. Then we find the copulas that
bound both below and above the set . Finally we determine the expressions for Kendall's tau and Spearman's rho for the horizontal and the bounding copulas
Distorted Copulas: Constructions and Tail Dependence
Given a copula C, we examine under which conditions on an order isomorphism Ï of [0, 1] the distortion C Ï: [0, 1]2 â [0, 1], C Ï(x, y) = Ï{C[Ïâ1(x), Ïâ1(y)]} is again a copula. In particular, when the copula C is totally positive of order 2, we give a sufficient condition on Ï that ensures that any distortion of C by means of Ï is again a copula. The presented results allow us to introduce in a more flexible way families of copulas exhibiting different behavior in the tails
The whole and its parts : why and how to disentangle plant communities and synusiae in vegetation classification
Most plant communities consist of different structural and ecological subsets, ranging from cryptogams to different tree layers. The completeness and approach with which these subsets are sampled have implications for vegetation classification. Nonâvascular plants are often omitted or sometimes treated separately, referring to their assemblages as âsynusiaeâ (e.g. epiphytes on bark, saxicolous species on rocks). The distinction of complete plant communities (phytocoenoses or holocoenoses) from their parts (synusiae or merocoenoses) is crucial to avoid logical problems and inconsistencies of the resulting classification systems. We here describe theoretical differences between the phytocoenosis as a whole and its parts, and outline consequences of this distinction for practise and terminology in vegetation classification. To implement a clearer separation, we call for modifications of the International Code of Phytosociological Nomenclature and the EuroVegChecklist. We believe that these steps will make vegetation classification systems better applicable and raise the recognition of the importance of nonâvascular plants in the vegetation as well as their interplay with vascular plants
Fortifying the Treatment of Prostate Cancer with Physical Activity
Over the past decade, significant data have shown that obese men experience a survival detriment after treatment for prostate cancer. While methods to combat obesity are of utmost importance for the prostate cancer patient, newer data reveal the overall metabolic improvements that accompany increased activity levels and intense exercise beyond weight loss. Along these lines, a plethora of data have shown improvement in prostate cancer-specific outcomes after treatment accompanied with these activity levels. This review discusses the metabolic mechanisms in which increased activity levels and exercise can help improve both outcomes for men treated for prostate cancer while lowering the side effects of treatment
Chemical compositions of stars in two stellar streams from the Galactic thick disk
We present abundances for 20 elements for stars in two stellar streams
identified by Arifyanto & Fuchs (2006, A&A, 449, 533): 18 stars from the
Arcturus stream and 26 from a new stream, which we call AF06 stream, both from
the Galactic thick disk. Results show both streams are metal-poor and very old
(1014 Gyrs) with kinematics and abundances overlapping with the properties
of local field thick disk stars. Both streams exhibit a range in metallicity
but with relative elemental abundances that are identical to those of thick
disk stars of the same metallicity. These results show that neither stream can
result from dissolution of an open cluster. It is highly unlikely that either
stream represents tidal debris from an accreted satellite galaxy. Both streams
most probably owe their origin to dynamical perturbations within the Galaxy.Comment: 10 figures, Accepted for publication in MNRA
Sailing into a dilemma : an economic and legal analysis of an EU trading scheme for maritime emissions
On the basis of a joint economic and legal analysis, we evaluate the effects of a âregionalâ (European)
emission trading scheme aiming at reducing emissions of international shipping. The focus lies on the
question which share of emissions from maritime transport activities to and from the EU can and
should be included in such a system. Our findings suggest that the attempt to implement an EU
maritime ETS runs into a dilemma. It is not possible to design a system that achieves emission
reductions in a cost efficient manner and is compatible with international law
Annotations for Rule-Based Models
The chapter reviews the syntax to store machine-readable annotations and
describes the mapping between rule-based modelling entities (e.g., agents and
rules) and these annotations. In particular, we review an annotation framework
and the associated guidelines for annotating rule-based models of molecular
interactions, encoded in the commonly used Kappa and BioNetGen languages, and
present prototypes that can be used to extract and query the annotations. An
ontology is used to annotate models and facilitate their description
Two distinct halo populations in the solar neighborhood. II. Evidence from stellar abundances of Mn, Cu, Zn, Y, and Ba
A previous study (Nissen & Schuster 2010) of 94 dwarf stars with -1.6 <
[Fe/H] < -0.4 has revealed the existence of two distinct halo populations with
a systematic difference in [alpha/Fe] at a given metallicity. In continuation
of that work, abundances of Mn, Cu, Zn, Y, and Ba are determined for the same
sample of stars. Equivalent widths of atomic lines are measured from high
resolution VLT/UVES and NOT/FIES spectra and used to derive precise abundance
ratios from an LTE analysis based on MARCS model atmospheres. Systematic
differences between the `high-alpha' and `low-alpha' halo populations are found
for [Cu/Fe], [Zn/Fe], and [Ba/Y], whereas there is no significant difference in
the case of [Mn/Fe]. At a given metallicity, [Cu/Fe] shows a large scatter that
is closely correlated with a corresponding scatter in [Na/Fe] and [Ni/Fe]. The
metallicity trends of [Cu/Fe], [Zn/Fe], and [Ba/Y] can be explained from
existing nucleosynthesis calculations if the high-alpha stars formed in regions
with such a high star formation rate that only massive stars and Type II
supernovae contributed to the chemical enrichment. The low-alpha stars, on the
other hand, most likely originate from systems with a slower chemical
evolution, characterized by additional enrichment from Type Ia supernovae and
low-mass AGB stars.Comment: Accepted for publication in A&
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