The Weiss conjecture on admissibility of observation operators for contraction semigroups

We prove the conjecture of George Weiss for contraction semigroups on Hilbert spaces, giving a characterization of infinite-time admissible observation functionals for a contraction semigroup, namely that such a functional C is infinite-time admissible if and only if there is an M > 0 such that parallel to IC(sI - A)(-1)parallel to less than or equal to M/root Re s for all s in the open right half-plane. Here A denotes the infinitesimal generator of the semigroup. The result provides a simultaneous generalization of several celebrated results from the theory of Hardy spaces involving Carleson measures and Hankel operators

Remarks on Input-to-State Stability and Non-Coercive Lyapunov Functions

We consider an abstract class of infinite-dimensional dynamical systems with inputs. For this class the significance of noncoercive Lyapunov functions is analyzed. It is shown that the existence of such Lyapunov functions implies integral input-to-integral state stability. Assuming further regularity it is possible to conclude input-to-state stability. For a particular class of linear systems with unbounded admissible input operators, explicit constructions of noncoercive Lyapunov functions are provided. The theory is applied to a heat equation with Dirichlet boundary conditions

Non-coercive Lyapunov functions for input-to-state stability of infinite-dimensional systems

We consider an abstract class of infinite-dimensional dynamical systems with inputs. For this class the significance of noncoercive Lyapunov functions is analyzed. It is shown that the existence of such Lyapunov functions implies norm-to-integral input-to-state stability (ISS). This property in turn is equivalent to ISS, if the system has some sort of regularity. For a particular class of linear systems with unbounded admissible input operators, explicit constructions of noncoercive Lyapunov functions are provided. The theory is applied to a heat equation with Dirichlet boundary conditions

Infinite-Dimensional Input-to-State Stability and Orlicz Spaces

In this work, the relation between input-to-state stability and integral input-to-state stability is studied for linear infinite-dimensional systems with an unbounded control operator. Although a special focus is laid on the case L∞, general function spaces are considered for the inputs. We show that integral input-to-state stability can be characterized in terms of input-to-state stability with respect to Orlicz spaces. Since we consider linear systems, the results can also be formulated in terms of admissibility. For parabolic diagonal systems with scalar inputs, both stability notions with respect to L∞ are equivalent

Beyond the ‘Tomlinson Trap’: analysing the effectiveness of section 1 of the Compensation Act 2006

One of the intentions underpinning section 1 of the Compensation Act 2006 was to provide reassurance to individual volunteers, and voluntary organisations, involved in what the provision called ‘desirable activities’ and including sport. The perception was that such volunteers, motivated by an apprehension about their increased vulnerability to negligence liability, and as driven by a fear of a wider societal compensation culture, were engaging excessively in risk-averse behaviour to the detriment of such socially desirable activities. Academic commentary on section 1 of the Compensation Act 2006 has largely regarded the provision as unnecessary and doing little more than restating existing common law practice. This article argues otherwise and, on critically reviewing the emerging jurisprudence, posits the alternative view that section 1, in practice, affords an enhanced level of protection and safeguarding for individuals undertaking functions in connection with a desirable activity. Nonetheless, the occasionally idiosyncratic judicial interpretation given to term ‘desirable activity’, potentially compounded by recent enactment of the Social Action, Responsibility and Heroism Act 2015, remains problematic. Two points of interest will be used to inform this debate. First, an analysis of the then House of Lords’ decision in Tomlinson and its celebrated ‘balancing exercise’ when assessing reasonableness in the context of negligence liability. Second, a fuller analysis of the application of section 1 in the specific context of negligence actions relating to the coaching of sport where it is argued that the, albeit limited, jurisprudence might support the practical utility of a heightened evidential threshold of gross negligence

‘Getting inside the wicket’: strategies for the social inclusion of British Pakistani Muslim cricketers

The England and Wales Cricket Board (ECB) are keen to increase the participation of British Asian groups, including those of British Pakistani Muslim (BPM) backgrounds, at mainstream levels of the game in order to meet their twin strategic aims of raising participation levels and fostering elite development. We argue that the potential to include BPM men in and through cricket is achievable, but strategies to engage them must address their social needs and circumstances rather than be superficial and tokenistic. Cricket agencies and bodies must be willing to adapt and change to become more inclusive, and indeed supportive of real meritocracy. Using research testimonies garnered from interviews with BPM men who play cricket at amateur mainstream and/or alternative formats of the game, we identify and forward strategies that can be activated by cricket development officers in order to create new possibilities for the social inclusion of BPM men

May Measurement Month 2019: An analysis of blood pressure screening results from Argentina

The Argentinean Society of Hypertension, in agreement with the May Measurement Month (MMM) initiative of the International Society of Hypertension, implemented for the third consecutive year a hypertension screening campaign. A volunteer cross-sectional survey was carried out in public spaces and health centres during the month of May 2019 across 33 cities in Argentina. Hypertension was defined as systolic blood pressure (BP) ≥140 mmHg and/or diastolic BP ≥90 mmHg based on the mean of the second and third BP measurements, or in those on treatment for high BP. A total of 94 523 individuals (53.9 ± 17.8 years old, 55 231women and 39 292 men), were evaluated. The age and sex standardized mean BP was 124.7/77.2 mmHg. Among participants, 34.7% were overweight (25-29.9 m/kg2) and 28.7% had obesity (≥30 m/kg2). Individuals identified as being overweight had BP 3/2 mmHg higher and individuals with obesity 6/4 mmHg higher than those with normal weight. The prevalence of hypertension was 52.5%. Although 81.1% were aware and 77.7% were on antihypertensive treatment, only 46.0% of all individuals with hypertension had their BP controlled. Moreover, 19.8% of those not on any antihypertensive medication were found with raised BP. The low level of control of hypertension generates the critical need for the development of community-based prevention strategies reinforcing strategies to increase the awareness and control of hypertension.Fil: Salazar, Martin Rogelio Enrique. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Garcia Vazquez, Fortunato. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Espeche, Walter. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Marquez, Diego. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Becerra, Pedro. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Martinez Marissi, Evangelina. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Sorasio, Viviana B.. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Staffieri, Gustavo J.. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Kalbermatter, Arnoldo. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: De Cerchio, Alejandro E.. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Beaney, Thomas. Imperial College London; Reino UnidoFil: Partington, Giles. Imperial College London; Reino UnidoFil: Poulter, Neil R.. Imperial College London; Reino UnidoFil: Marín, Marcos. Sociedad Argentina de Hipertensión Arterial; ArgentinaFil: Ennis, Irene Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani". Universidad Nacional de La Plata. Facultad de Ciencias Médicas. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; Argentina. Sociedad Argentina de Hipertensión Arterial; Argentin