Modulation instability and conservation of energy:toward a new model

L'articolo analizza la propagazione in regime nonlineare di un segnale ottico CW in presenza di una "piccola" perturbazione. In letteratura sono presenti lavori che specificano i parametri fisici che regolano l'interazione tra il segnale CW e la perturbazione ma non si hanno indicazioni relative ai limiti di applicabilità dei modelli proposti. Obiettivo principale di questo lavoro è rappresentato dalla definizione dei parametri che "attivano" l'instabilità di modulazione e regolano il regime di propagazione nonlineare. A tal fine, il regime di propagazione nonlineare è analizzato vincolandolo al principio di conservazione dell'energia

Role of post mortem CT (PMCT) in high energy traumatic deaths

Background. Post Mortem Computed Tomography (PMCT) is being increasingly implemented in forensic field and could be an adjuvant to classic autopsies. In this study we evaluated the feasibility of complementation of conventional autopsy in trauma victims with PMCT. Materials and methods. A total of 21 subjects, who had sustained various types of blunt high-energy trauma, were selected from the casuistry of the Section of Legal Medicine at University of Pisa: before autopsy, a PMCT examination (Toshiba Aquilion 16 CT scanner) was performed, and after the acquisition of the raw images, MPR and VR reconstructions were performed with dedicated software. Results. PMCT is more sensitive than conventional autopsy in detecting skeletal injuries, whilst autopsy constitutes the method of choice for the detection of thoracic and abdominal visceral injuries. Conclusion. PMCT should be considered a useful tool in addition to conventional autopsy in evaluating trauma victims: it detects further bone fractures in body parts difficult to investigate during autopsy (i.e. posterior regions), facilitating the pathologist in the reconstruction of events and in determining the cause of death

The Application of Quality of Life in Services for Persons with Intellectual and Developmental Disabilities: Lines of intervention in Spain and Italy

The concept of quality of life (QOL) has become a measurable construct of great value to all people, including people with intellectual and developmental disabilities (IDD). In particular, the field of IDD is currently experiencing a paradigm shift related to beliefs, assumptions, policies, and practices concerning people with disabilities and their families and the place and role they play in society. This article starts by reconstructing the state of the art of the application of QOL in Social Services, reconstructing its research developments, operational declinations and influences in social policies in Spain and Italy

Criterios conceptuales del análisis geotécnico de macizos rocosos utilizados para la construcción de una presa de gravedad en hormigón en la cuenca del Ramal H (Tandil)

La conceptualización básica de un estudio geotécnico en una presa de gravedad de hormigón en ejecución en la cuenca del ramal H, Tandil, Provincia de Buenos Aires, Argentina, comenzó con la determinación de las distintas zonas litoestructurales que integran el macizo rocoso bajo análisis. Para cada una de las zonas litoestructurales identificadas se realizó posteriormente la determinación geotécnica de sus características mediante la obtención de los valores de resistencia, de deformabilidad e, indirectamente, de fracturación mediante los parámetros hidrogeológicos (permeabilidad y presión de agua intersticial) del macizo rocoso para su aplicación en a) la fundación, b) las tareas de excavación y c) los materiales de construcción. En el presente trabajo se desarrolla la secuencia teórico-práctica utilizada para alcanzar la clasificación geomecánica que permite la sectorización necesaria para la ejecución de las obras.Facultad de Ciencias Naturales y Muse

Criterios conceptuales del análisis geotécnico de macizos rocosos utilizados para la construcción de una presa de gravedad en hormigón en la cuenca del Ramal H (Tandil)

La conceptualización básica de un estudio geotécnico en una presa de gravedad de hormigón en ejecución en la cuenca del ramal H, Tandil, Provincia de Buenos Aires, Argentina, comenzó con la determinación de las distintas zonas litoestructurales que integran el macizo rocoso bajo análisis. Para cada una de las zonas litoestructurales identificadas se realizó posteriormente la determinación geotécnica de sus características mediante la obtención de los valores de resistencia, de deformabilidad e, indirectamente, de fracturación mediante los parámetros hidrogeológicos (permeabilidad y presión de agua intersticial) del macizo rocoso para su aplicación en a) la fundación, b) las tareas de excavación y c) los materiales de construcción. En el presente trabajo se desarrolla la secuencia teórico-práctica utilizada para alcanzar la clasificación geomecánica que permite la sectorización necesaria para la ejecución de las obras.Facultad de Ciencias Naturales y Muse

Direct detection of spin polarization in photoinduced charge transfer through a chiral bridge

It is well assessed that the charge transport through a chiral potential barrier can result in spin-polarized charges. The possibility of driving this process through visible photons holds tremendous potential for several aspects of quantum information science, e.g., the optical control and readout of qubits. In this context, the direct observation of this phenomenon via spin-sensitive spectroscopies is of utmost importance to establish future guidelines to control photo-driven spin selectivity in chiral structures. Here, we provide direct proof that time-resolved electron paramagnetic resonance (EPR) can be used to detect long-lived spin polarization generated by photoinduced charge transfer through a chiral bridge. We propose a system comprising CdSe quantum dots (QDs), as a donor, and C60, as an acceptor, covalently linked through a saturated oligopeptide helical bridge (χ) with a rigid structure of ∼10 Å. Time-resolved EPR spectroscopy shows that the charge transfer in our system results in a C60 radical anion, whose spin polarization maximum is observed at longer times with respect to that of the photogenerated C60 triplet state. Notably, the theoretical modelling of the EPR spectra reveals that the observed features may be compatible with chirality-induced spin selectivity, but the electronic features of the QD do not allow the unambiguous identification of the CISS effect. Nevertheless, we identify which parameters need optimization for unambiguous detection and quantification of the phenomenon. This work lays the basis for the optical generation and direct manipulation of spin polarization induced by chirality

The Blood Pressure "Uncertainty Range" – a pragmatic approach to overcome current diagnostic uncertainties (II)

A tremendous amount of scientific evidence regarding the physiology and physiopathology of high blood pressure combined with a sophisticated therapeutic arsenal is at the disposal of the medical community to counteract the overall public health burden of hypertension. Ample evidence has also been gathered from a multitude of large-scale randomized trials indicating the beneficial effects of current treatment strategies in terms of reduced hypertension-related morbidity and mortality. In spite of these impressive advances and, deeply disappointingly from a public health perspective, the real picture of hypertension management is overshadowed by widespread diagnostic inaccuracies (underdiagnosis, overdiagnosis) as well as by treatment failures generated by undertreatment, overtreatment, and misuse of medications. The scientific, medical and patient communities as well as decision-makers worldwide are striving for greatest possible health gains from available resources. A seemingly well-crystallised reasoning is that comprehensive strategic approaches must not only target hypertension as a pathological entity, but rather, take into account the wider environment in which hypertension is a major risk factor for cardiovascular disease carrying a great deal of our inheritance, and its interplay in the constellation of other, well-known, modifiable risk factors, i.e., attention is to be switched from one's "blood pressure level" to one's absolute cardiovascular risk and its determinants. Likewise, a risk/benefit assessment in each individual case is required in order to achieve best possible results. Nevertheless, it is of paramount importance to insure generalizability of ABPM use in clinical practice with the aim of improving the accuracy of a first diagnosis for both individual treatment and clinical research purposes. Widespread adoption of the method requires quick adjustment of current guidelines, development of appropriate technology infrastructure and training of staff (i.e., education, decision support, and information systems for practitioners and patients). Progress can be achieved in a few years, or in the next 25 years

Is blood pressure reduction a valid surrogate endpoint for stroke prevention? an analysis incorporating a systematic review of randomised controlled trials, a by-trial weighted errors-in-variables regression, the surrogate threshold effect (STE) and the biomarker-surrogacy (BioSurrogate) evaluation schema (BSES)

<p>Abstract</p> <p>Background</p> <p>Blood pressure is considered to be a leading example of a valid surrogate endpoint. The aims of this study were to (i) formally evaluate systolic and diastolic blood pressure reduction as a surrogate endpoint for stroke prevention and (ii) determine what blood pressure reduction would predict a stroke benefit.</p> <p>Methods</p> <p>We identified randomised trials of at least six months duration comparing any pharmacologic anti-hypertensive treatment to placebo or no treatment, and reporting baseline blood pressure, on-trial blood pressure, and fatal and non-fatal stroke. Trials with fewer than five strokes in at least one arm were excluded. Errors-in-variables weighted least squares regression modelled the reduction in stroke as a function of systolic blood pressure reduction and diastolic blood pressure reduction respectively. The lower 95% prediction band was used to determine the minimum systolic blood pressure and diastolic blood pressure difference, the surrogate threshold effect (STE), below which there would be no predicted stroke benefit. The STE was used to generate the surrogate threshold effect proportion (STEP), a surrogacy metric, which with the R-squared trial-level association was used to evaluate blood pressure as a surrogate endpoint for stroke using the Biomarker-Surrogacy Evaluation Schema (BSES3).</p> <p>Results</p> <p>In 18 qualifying trials representing all pharmacologic drug classes of antihypertensives, assuming a reliability coefficient of 0.9, the surrogate threshold effect for a stroke benefit was 7.1 mmHg for systolic blood pressure and 2.4 mmHg for diastolic blood pressure. The trial-level association was 0.41 and 0.64 and the STEP was 66% and 78% for systolic and diastolic blood pressure respectively. The STE and STEP were more robust to measurement error in the independent variable than R-squared trial-level associations. Using the BSES3, assuming a reliability coefficient of 0.9, systolic blood pressure was a B + grade and diastolic blood pressure was an A grade surrogate endpoint for stroke prevention. In comparison, using the same stroke data sets, no STEs could be estimated for cardiovascular (CV) mortality or all-cause mortality reduction, although the STE for CV mortality approached 25 mmHg for systolic blood pressure.</p> <p>Conclusions</p> <p>In this report we provide the first surrogate threshold effect (STE) values for systolic and diastolic blood pressure. We suggest the STEs have face and content validity, evidenced by the inclusivity of trial populations, subject populations and pharmacologic intervention populations in their calculation. We propose that the STE and STEP metrics offer another method of evaluating the evidence supporting surrogate endpoints. We demonstrate how surrogacy evaluations are strengthened if formally evaluated within specific-context evaluation frameworks using the Biomarker- Surrogate Evaluation Schema (BSES3), and we discuss the implications of our evaluation of blood pressure on other biomarkers and patient-reported instruments in relation to surrogacy metrics and trial design.</p