897 research outputs found
Morphisms of Projective Varieties from the viewpoint of Minimal Model Theory
In this Lecture Notes we present, in a sufficiently self contained way, our
contributions and interests in the field of Minimal Model Theory. We study
Fano-Mori spaces, both from the biregular and the birational point of view. For
the former we recall and develop Kawamata's Base Point Free technique and some
of Mori's deformation arguments. For the latter we lean on Sarkisov and
#-Minimal Model Programs. In writing these notes we want to give our point of
view on this area of research. We are not trying to give a treatment of the
whole subject. These notes collect some topics we presented in three
mini-courses which were held in Wykno (Pl) (1999), Recife (Br) (2000) and
Ferrara (It) (2000), respectively.Comment: 78 pages, AMSLaTeX2e, to appear on Dissertationes Mathematicae,
Polish Ac. Sc. Warsa
The cone of curves of Fano varieties of coindex four
We classify the cones of curves of Fano varieties of dimension greater or
equal than five and (pseudo)index dim X -3, describing the number and type of
their extremal rays.Comment: 27 pages; changed the numbering of Theorems, Definitions,
Propositions, etc. in accordance with the published version to avoid
incorrect reference
On the Hilbert scheme of curves in higher-dimensional projective space
In this paper we prove that, for any , there exist infinitely many
and for each of them a smooth, connected curve in such
that lies on exactly irreducible components of the Hilbert scheme
\hilb(\P^r). This is proven by reducing the problem to an analogous statement
for the moduli of surfaces of general type.Comment: latex, 12 pages, no figure
Generalization of appetitive conditioned responses
A stimulus (conditioned stimulus, CS) associated with an appetitive unconditioned
stimulus (US) acquires positive properties and elicits appetitive conditioned responses
(CR). Such associative learning has been examined extensively in animals with food
as the US, and results are used to explain psychopathologies (e.g., substanceârelated
disorders or obesity). Human studies on appetitive conditioning exist, too, but we still
know little about generalization processes. Understanding these processes may explain
why stimuli not associated with a drug, for instance, can elicit craving. Fortyâseven
hungry participants underwent an appetitive conditioning protocol during which one
of two circles with different diameters (CS+) became associated with an appetitive US
(chocolate or salty pretzel, according to participantsâ preference) but never the other
circle (CSâ). During generalization, US were delivered twice and the two CS were
presented again plus four circles (generalization stimuli, GS) with gradually increasing
diameters from CSâ to CS+. We found successful appetitive conditioning as reflected
in appetitive subjective ratings (positive valence, higher contingency) and physiological responses (startle attenuation and larger skin conductance respon
Two-week joint mobilization intervention improves self-reported function, range of motion, and dynamic balance in those with chronic ankle instability
We examined the effect of a 2-week anterior-to-posterior ankle joint mobilization intervention on weight-bearing dorsiflexion
range of motion (ROM), dynamic balance, and self-reported function in subjects with chronic ankle instability (CAI). In this prospective
cohort study, subjects received six Maitland Grade III anterior-to-posterior joint mobilization treatments over 2 weeks. Weightbearing
dorsiflexion ROM, the anterior, posteromedial, and posterolateral reach directions of the Star Excursion Balance Test (SEBT),
and self-reported function on the Foot and Ankle Ability Measure (FAAM) were assessed 1 week before the intervention (baseline),
prior to the first treatment (pre-intervention), 24â48 h following the final treatment (post-intervention), and 1 week later (1-week
follow-up) in 12 adults (6 males and 6 females) with CAI. The results indicate that dorsiflexion ROM, reach distance in all directions of
the SEBT, and the FAAM improved (p < 0.05 for all) in all measures following the intervention compared to those prior to the intervention.
No differences were observed in any assessments between the baseline and pre-intervention measures or between the postintervention
and 1-week follow-up measures (p > 0.05). These results indicate that the joint mobilization intervention that targeted
posterior talar glide was able to improve measures of function in adults with CAI for at least 1 week
Evidence for impaired extinction learning in humans after distal stress exposure
Stressful or traumatic events can be risk factors for anxiety or trauma- and stressor-related disorders. In this regard, it has been shown that stress affects aversive learning and memory processes. In rodents, stress exposure 10 days prior to fear acquisition impairs fear extinction. However, in humans the effect of distal stress on fear conditioning is sparse. Therefore, we examined the influence of distal stress on fear memory in humans in two studies. In Study 1, participants underwent either socially evaluated cold-pressor test (SECPT) or sham procedure 10 days or 40 min before a fear conditioning paradigm (four groups, N = 78). In Study 2, context effects were examined by conducting SECPT and sham procedures 10 days prior conditioning either in the later fear conditioning context or in another context (three groups, N = 69). During acquisition phase, one geometrical shape (conditioned stimulus, CS+) was paired with painful electric shocks (unconditioned stimulus, US), but never a second shape (CSâ). Extinction phase was identical to acquisition, but without US delivery. Importantly, for Study 1 these phases were conducted on one day, while for Study 2 on two separated days. Successful fear acquisition was indicated by aversive ratings and startle potentiation to CS+ versus CSâ in both studies. Interestingly, participants stressed 10 days earlier showed impaired extinction on the implicit level (startle potentiation to CS+ vs. CSâ) in Study 1 and only in the acquisition context on the explicit level (aversive ratings for CS+ vs. CSâ) in Study 2. In sum, distal stress may strengthen later acquired fear memories and thereby impair fear extinction. This finding could have clinical implications, showing that prior stress exposure sensitizes later aversive processing and impairs therapy
Vulnerabilidade social e a construção de estratégias de enfrentamento e adaptação para pecuaristas de corte no Rio Grande do Sul.
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