1,721,077 research outputs found
On rectifiable measures in Carnot groups: representation
Full text linkThis paper deals with the theory of rectifiability in arbitrary Carnot groups, and in particular with the study of the notion of P -rectifiable measure. First, we show that in arbitrary Carnot groups the natural infinitesimal definition of rectifiabile measure, i.e., the definition given in terms of the existence of flat tangent measures, is equivalent to the global definition given in terms of coverings with intrinsically differentiable graphs, i.e., graphs with flat Hausdorff tangents. In general we do not have the latter equivalence if we ask the covering to be made of intrinsically Lipschitz graphs. Second, we show a geometric area formula for the centered Hausdorff measure restricted to intrinsically differentiable graphs in arbitrary Carnot groups. The latter formula extends and strengthens other area formulae obtained in the literature in the context of Carnot groups. As an application, our analysis allows us to prove the intrinsic C1 -rectifiability of almost all the preimages of a large class of Lipschitz functions between Carnot groups. In particular, from the latter result, we obtain that any geodesic sphere in a Carnot group equipped with an arbitrary left-invariant homogeneous distance is intrinsic C1 -rectifiable
Impact of instrumental analysis of stiff knee gait on treatment appropriateness and associated costs in stroke patients
No full textBACKGROUND: Stiff Knee Gait (SKG) in stroke patients is typically treated by the
inhibition of the rectus femoris (RF) with botulinum toxin (BoNT) after clinical
evaluation, obtaining an average pooled recovery in knee flexion (KF) of 7
degrees.
PURPOSE: Our hypothesis is that this limited recovery after BoNT could depend on
the inadequacy in the selection of patients to be treated. The aim of this study
was to assess the percentage of inappropriate treatments (PIT) that can be
avoided when instrumental gait analysis (GA) is used, and to estimate the
associated cost savings.
METHODS: We retrospectively analyzed GA data from chronic stroke patients with
SKG and clinically assessed knee extensors spasticity referred to our laboratory
over a five-year period. Gait kinematics and dynamic electromyography data were
used. Patients were considered unsuitable for RF inhibition when: their SKG was
determined by inadequate ankle push-off (APO) rather than by a brake from knee
extensors, based on a previously published algorithm using gait kinematics
(PITKIN); when RF was not active during KF (PITEMG); and when a proximal braking
mechanism was found, if this was not due to RF activity (PITGA).
RESULTS: 160 patients, age 20-87 years, gait speed 9-77%height/s, KF peak -4-44
degrees, were included. Of these, in 119 cases poor APO was the main cause of
SKG, thus leading to PITKIN = 74%. In 48 out of 107 non-obese subjects, RF
spasticity was not involved in SKG, resulting in PITEMG = 45%. Finally, patients
with a braking activity as the main cause and concurrent RF activity were
20/107 = 19%, resulting in PITGA = 81% SIGNIFICANCE: When treating SKG, proper
use of GA can reduce the percentage of inappropriate treatments by BoNT at the RF
up to 81%. Savings are in the order of €100k/year when considering centers
treating 100 or more patients/year
On Rectifiable Measures in Carnot Groups: Existence of Density
Full text linkIn this paper, we start a detailed study of a new notion of rectifiability in Carnot groups: we say that a Radon measure is [Formula: see text] -rectifiable, for [Formula: see text] , if it has positive h-lower density and finite h-upper density almost everywhere, and, at almost every point, it admits a unique tangent measure up to multiples. First, we compare [Formula: see text] -rectifiability with other notions of rectifiability previously known in the literature in the setting of Carnot groups, and we prove that it is strictly weaker than them. Second, we prove several structure properties of [Formula: see text] -rectifiable measures. Namely, we prove that the support of a [Formula: see text] -rectifiable measure is almost everywhere covered by sets satisfying a cone-like property, and in the particular case of [Formula: see text] -rectifiable measures with complemented tangents, we show that they are supported on the union of intrinsically Lipschitz and differentiable graphs. Such a covering property is used to prove the main result of this paper: we show that a [Formula: see text] -rectifiable measure has almost everywhere positive and finite h-density whenever the tangents admit at least one complementary subgroup
Intrinsically Lipschitz functions with normal target in Carnot groups
Full text linkWe provide a Rademacher theorem for intrinsically Lipschitz functions φ: U ⊆
W → L, where U is a Borel set, W and L are complementary subgroups of a Carnot group, where we require that L is a normal subgroup. Our hypotheses are satisfied for example when W is a horizontal subgroup. Moreover, we provide an area formula for this class of intrinsically Lipschitz functions
Motor unit discharge pattern and conduction velocity in patients with upper motor neuron syndrome
No full textUdgivelsesdato: FE
Il mercato del lavoro dei politici
No full textLe classi dirigenti hanno una funzione importante nelle nostre società. Rendono possibili obiettivi altrimenti irragiungibili, rimuovendo gli ostacoli che inibiscono la crescita nel lungo periodo. Ma come si formano? Il rapporto analizza la selezione dei politici in italia
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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