773 research outputs found
Tunable non-Gaussian resources for continuous-variable quantum technologies
We introduce and discuss a set of tunable two-mode states of
continuous-variable systems, as well as an efficient scheme for their
experimental generation. This novel class of tunable entangled resources is
defined by a general ansatz depending on two experimentally adjustable
parameters. It is very ample and flexible as it encompasses Gaussian as well as
non-Gaussian states. The latter include, among others, known states such as
squeezed number states and de-Gaussified photon-added and photon-subtracted
squeezed states, the latter being the most efficient non-Gaussian resources
currently available in the laboratory. Moreover, it contains the classes of
squeezed Bell states and even more general non-Gaussian resources that can be
optimized according to the specific quantum technological task that needs to be
realized. The proposed experimental scheme exploits linear optical operations
and photon detections performed on a pair of uncorrelated two--mode Gaussian
squeezed states. The desired non-Gaussian state is then realized via ancillary
squeezing and conditioning. Two independent, freely tunable experimental
parameters can be exploited to generate different states and to optimize the
performance in implementing a given quantum protocol. As a concrete instance,
we analyze in detail the performance of different states considered as
resources for the realization of quantum teleportation in realistic conditions.
For the fidelity of teleportation of an unknown coherent state, we show that
the resources associated to the optimized parameters outperform, in a
significant range of experimental values, both Gaussian twin beams and
photon-subtracted squeezed states.Comment: 13 pages, 7 figure
Uniqueness of renormalized solutions to nonlinear elliptic equations with a lower order term and right-hand side in
Continuous-Variable Entangled States of Light carrying Orbital Angular Momentum
The orbital angular momentum of light, unlike spin, is an
infinite-dimensional discrete variable and may hence offer enhanced
performances for encoding, transmitting, and processing information in the
quantum regime. Hitherto, this degree of freedom of light has been studied
mainly in the context of quantum states with definite number of photons. On the
other hand, field-quadrature continuous-variable quantum states of light allow
implementing many important quantum protocols not accessible with photon-number
states. Here, we present the first generation and complete experimental
characterization of a bipartite continuous-variable Gaussian entangled state
endowed with non-zero orbital angular momentum. A q-plate is used to transfer
the continuous-variable entanglement initially generated in polarization into
orbital angular momentum. We then apply a reconfigurable homodyne detector to
various combinations of orbital angular momentum modes in order to reconstruct
the entire quantum-state covariance matrix, by directly measuring the
fluctuations of quadrature operators. Our work is a step towards generating
multipartite continuous-variable entanglement in a single optical beam.Comment: To appear in Phys. Rev.
Palliative sedation in patients with advanced cancer followed at home: a prospective study.
Abstract
CONTEXT:
Home care programs in Italy.
OBJECTIVES:
The aim of this study was to assess a protocol for palliative sedation (PS) performed at home.
METHODS:
A total of 219 patients were prospectively assessed to evaluate a PS protocol in patients with advanced cancer followed at home by two home care programs with different territorial facilities. The protocol was based on stepwise administration of midazolam.
RESULTS:
A total of 176 of the patients died at home, and PS was performed in 24 of these patients (13.6%). Younger patients received the procedure more frequently than older patients (P=0.012). The principal reasons to start PS were agitated delirium (n=20) and dyspnea (n=4). Mean duration of PS was 42.2±30.4 hours, and the mean doses of midazolam were 23-58 mg/day. Both the home care team and the patients' relatives expressed optimal or good levels of satisfaction with the procedure in all but one case, respectively.
CONCLUSION:
This protocol for PS was feasible and effective in minimizing distress for a subgroup of patients who died at home. The characteristics of patients who may be effectively sedated at home should be better explored in future studies
Opioid switching in patients with advanced cancer followed at home. A retrospective analysis
Abstract
CONTEXT:
Opioid switching has been found to improve opioid responsiveness in different conditions. However, data on opioid switching performed at home are almost nonexistent, despite the fact that most patients are followed at home.
OBJECTIVES:
The aim of this retrospective survey was to determine frequency, indications, usefulness, and safety of opioid switching when treating advanced cancer-related pain in patients followed at home.
METHODS:
A retrospective review of data from patients with advanced cancer followed at home by three home care teams for a period of two years was performed. Patients who had their opioids switched were selected. Reasons for switching opioid doses and routes of administration and outcomes were collected.
RESULTS:
Two hundred one (17%) of 1141 patients receiving "strong" opioids were switched. The mean Karnofsky Performance Status score was 35.6, and the median survival was 30 days. The most frequent reason to switch was for convenience, and the most frequent switch was to parenteral morphine. In most patients, a better analgesic response was observed. Patients who were switched to parenteral morphine had a shorter survival in comparison with other opioid sequences (P<0.0005). After switching, opioid doses were increased by 23% and 41%, after a week and at time of death, respectively.
CONCLUSION:
Opioid switching was useful for most patients in the home environment, at least in less complex circumstances, when done by experienced home care teams. Prospective studies are needed to provide information about the decision to admit to hospital for this purpose and the predictive factors that may relatively contraindicate transportation to a facility in severely ill patients
Palliative sedation in advanced cancer patients followed at home: a retrospective analysis.
Abstract
CONTEXT:
Data regarding palliative sedation at home in dying patients are lacking.
OBJECTIVES:
To describe the frequency, indication, and modality of palliative sedation (PS) in patients followed at home.
METHODS:
A retrospective analysis of home care cancer patients was performed. Patients who received PS before dying were selected and information about epidemiologic characteristics, indications, duration, drugs, and outcomes was collected.
RESULTS:
Of 370 medical charts of patients who died at home, 49 patients received PS before dying. PS was proposed by the team, relatives, or both in 63.3%, 4.1%, and 32.6% of cases, respectively. Delirium alone or in combination with other symptoms was the most frequent indication to begin PS. Midazolam was the most frequently used drug to initiate PS (98%), at a mean dose of 28.1 mg/day, in combination with parenteral morphine (84.7%) at a mean dose of 25.4 mg/day. At the time of death, midazolam was administered in 98% of patients (mean dose 22.3 mg/day), combined with parenteral morphine in 87.8% of patients (mean dose 28.1 mg/day). Satisfaction for physicians and principal caregivers after PS was good in 46 and 48 cases, respectively.
CONCLUSION:
PS at home seems to be a feasible treatment option among selected patients and makes a potentially important contribution to improving care for those who choose to die at home
Use of information and communication technology and tools in the internazionalization department of a higher education institution
El uso de nuevas herramientas tecnológicas (TICS) es necesario a fin de que una Oficina de Proyectos internacionales trabaje de una manera más eficiente. Las TICS pueden usarse para apoyar la presentación de una propuesta (sitios para seguir los próximos llamados, herramientas para crear redes de trabajo) así como para el gerenciamiento del proyecto en sí (herramientas para gerenciar el proyecto, para desarrollar reuniones virtuales, para facilitar el trabajo virtual en equipos).Asimismo, las TICS favorecen la investigación (brindan acceso a información pública y especializada) y el entrenamiento (eLearning). Las comunicaciones internas y externas se ven mejoradas por las herramientas de comunicación sincrónicasy asincrónicas. La evaluación de las actividades se beneficia a través de las encuestas en línea, y la administración financiera de un proyecto se facilita con los sistemas contables. Las TICs están cambiando completamente la forma en que los proyectos internacionales se llevan adelante, haciendo posible y habituales realidades que antes eran inimaginables (por ejemplo, las reuniones virtuales). Este trabajo brinda una mirada a todos los posibles usos de las TICS en un Proyecto Internacional, y hace sugerencias sobre las herramientas a usar, basadas en la experiencia de los autores
Trapped Ions in Laser Fields: a Benchmark for Deformed-Quantum Oscillators
Some properties of the non--linear coherent states (NCS), recognized by Vogel and de Matos Filho as dark states of a trapped ion, are extended to NCS on a circle, for which the Wigner functions are presented. These states are obtained by applying a suitable displacement operator to the vacuum state. The unity resolutions in terms of the projectors . is also used for introducing the probability distribution funtion while the existence of a measure is exploited for extending the P-representation to these states. The weight of the n-th Fock state of the NCS relative to a trapped ion with Lamb-Dicke parameter oscillates so wildly as grows up to infinity that the normalized NCS fill the open circle in the complex -plane. In addition this prevents the existence of a measure including normalizable states only. This difficulty is overcome by introducing a family of deformations which are rational functions of n, each of them admitting a measure. By increasing the degree of these rational approximations the deformation of a trapped ion can be approximated with any degree of accuracy and the formalism of the P-representation can be applied
The use of fentanyl buccal tablets for breakthrough pain by using doses proportional to opioid basal regimen in a home care setting.
Abstract
The dose of rapid onset opioids to be given for breakthrough cancer pain (BTcP) is controversial. Dose proportional to the basal opioid regimen seem to be safe and effective in hospital units. However, data in other less protected settings, like home care, are lacking. The aim of this open-label study was to assess the efficacy and safety in a group of patients with BTcP followed at home, after giving a dose of fentanyl buccal tablets (FBT) proportional to the opioid basal regimen, skipping the steps for dose titration. Consecutive patients admitted to a home care program presenting BTcP episodes and receiving stable doses of opioids for background pain were selected. Data from four consecutive episodes of BTcP were collected. For each episode, patients were instructed to routinely collect changes in pain intensity and severe adverse effects when pain got severe (T0) and to reassess the same items 15 min after FBT, given as a rescue medication in doses proportional to the daily opioid doses used for background pain (T15). One hundred twenty episodes of BTcP were recorded in 30 patients. One hundred eight episodes were defined as successfully treated, while 12 episodes required a further administration of opioids. Pain intensity significantly decreased at T15 (p < 0.001). In 95.5 and 90.8 % of episodes treated, there was a reduction in pain intensity of more than 33 and 50 %, respectively. No relevant adverse effects were recorded, even in older patients. This study suggests that FBT given in doses proportional to the basal opioid regimen for the management of BTcP is very effective and safe in clinical practice in the home care setting
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