Reestudio de Zanthoxylum Coco Gill

En un reestudio de Zanthoxylum coco Gill. (sinónimoFagara coco Gill. (Engl.)), especie de Bolivia y Argentina de la familia de las Rutáceas, se han aislado la piranoquinolina angular jlindersina y la cumarina prenilada aurapteno. Estos resultados apoyan el criterio que las cumarinas se acumulan también en las especies sudamericanas de Zanthoxylum. La validez de estos datos como marcadores quimiosistemáticos es discutida

Ambiguity Uncertainty and Risk: Reframing the task of suicide risk assessment and prevention in acute in-patient mental health

The work of the National Confidential Inquiry into Suicide by People with Mental Illness has served to draw attention to the issue of suicide amongst users of mental health services including inpatient and provided the basis for a series of recommendations aimed at improving practice (Appleby et al., 2001, NIMHE 2003). Such recommendations include further training on risk assessment for practitioners. However, representing the problem of suicide as one which can be 'managed' by risk assessment particularly quantitative actuarial approaches implicitly misrepresents the phenomena of suicidality as something which can predicted and therefore managed may be inherently unpredictable at the level of the individual over the short term. We need instead to acknowledge that our work with service users who may be contemplating suicide embraces and acknowledges both uncertainty and ambiguity and seeks to assess risk phenomenologically at the level of the individual such that by understanding their reasons for living and dying we can work in partnership with them to find hope

Identities for hyperelliptic P-functions of genus one, two and three in covariant form

We give a covariant treatment of the quadratic differential identities satisfied by the P-functions on the Jacobian of smooth hyperelliptic curves of genera 1, 2 and 3

K-Rational D-Brane Crystals

In this paper the problem of constructing spacetime from string theory is addressed in the context of D-brane physics. It is suggested that the knowledge of discrete configurations of D-branes is sufficient to reconstruct the motivic building blocks of certain Calabi-Yau varieties. The collections of D-branes involved have algebraic base points, leading to the notion of K-arithmetic D-crystals for algebraic number fields K. This idea can be tested for D0-branes in the framework of toroidal compactifications via the conjectures of Birch and Swinnerton-Dyer. For the special class of D0-crystals of Heegner type these conjectures can be interpreted as formulae that relate the canonical Neron-Tate height of the base points of the D-crystals to special values of the motivic L-function at the central point. In simple cases the knowledge of the D-crystals of Heegner type suffices to uniquely determine the geometry.Comment: 36 page

On sums of squares and on elliptic curves over function fields

It has long been known that every positive semidefinite function of R(x, y) is the sum of four squares. This paper gives the first example of such a function which is not expressible as the sum of three squares. The proof depends on the determination of the points on a certain elliptic curve defined over C(x). The 2-component of the Tate-Safarevic group of this curve is nontrivial and infinitely divisible.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33657/1/0000167.pd

Borel-Cantelli sequences

A sequence $\{x_{n}\}_1^\infty$ in $[0,1)$ is called Borel-Cantelli (BC) if for all non-increasing sequences of positive real numbers $\{a_n\}$ with $\underset{i=1}{\overset{\infty}{\sum}}a_i=\infty$ the set $$\underset{k=1}{\overset{\infty}{\cap}} \underset{n=k}{\overset{\infty}{\cup}} B(x_n, a_n))=\{x\in[0,1)\mid |x_n-x|<a_n \text{for} \infty \text{many}n\geq1\}$$ has full Lebesgue measure. (To put it informally, BC sequences are sequences for which a natural converse to the Borel-Cantelli Theorem holds). The notion of BC sequences is motivated by the Monotone Shrinking Target Property for dynamical systems, but our approach is from a geometric rather than dynamical perspective. A sufficient condition, a necessary condition and a necessary and sufficient condition for a sequence to be BC are established. A number of examples of BC and not BC sequences are presented. The property of a sequence to be BC is a delicate diophantine property. For example, the orbits of a pseudo-Anosoff IET (interval exchange transformation) are BC while the orbits of a "generic" IET are not. The notion of BC sequences is extended to more general spaces.Comment: 20 pages. Some proofs clarifie

Rational approximation and arithmetic progressions

A reasonably complete theory of the approximation of an irrational by rational fractions whose numerators and denominators lie in prescribed arithmetic progressions is developed in this paper. Results are both, on the one hand, from a metrical and a non-metrical point of view and, on the other hand, from an asymptotic and also a uniform point of view. The principal novelty is a Khintchine type theorem for uniform approximation in this context. Some applications of this theory are also discussed

Testing Hardy nonlocality proof with genuine energy-time entanglement

We show two experimental realizations of Hardy ladder test of quantum nonlocality using energy-time correlated photons, following the scheme proposed by A. Cabello \emph{et al.} [Phys. Rev. Lett. \textbf{102}, 040401 (2009)]. Unlike, previous energy-time Bell experiments, these tests require precise tailored nonmaximally entangled states. One of them is equivalent to the two-setting two-outcome Bell test requiring a minimum detection efficiency. The reported experiments are still affected by the locality and detection loopholes, but are free of the post-selection loophole of previous energy-time and time-bin Bell tests.Comment: 5 pages, revtex4, 6 figure