Mixture of multiple copies of maximally entangled states is quasi-pure

Employing the general BXOR operation and local state discrimination, the mixed state of the form \rho^{(k)}_{d}=\frac{1}{d^{2}}\sum_{m,n=0}^{d-1}(|\phi_{mn}><\phi_{mn}|)^{\otim es k} is proved to be quasi-pure, where $\{|\phi_{mn}>\}$ is the canonical set of mutually orthogonal maximally entangled states in $d\times d$. Therefore irreversibility does not occur in the process of distillation for this family of states. Also, the distillable entanglement is calculated explicitly.Comment: 6 pages, 1 figure. The paper is subtantially revised and the general proof is give

Application of LADM for disaster prone areas and communities

Disaster prevention, response and recovery require information about land tenure. Though, in many high-risk contexts, such records are non-existent or not up to date. As a result, vulnerable groups are often passed over by the government during risk management activities. At present there exists no dedicated tool for supporting land tenure recordation of all people-to-land relationships for the purposes of disaster risk management. More specifically, the required supportive data models and standards that could enable integration of concepts from the respective domains of land administration and disaster risk management are also lacking. Standardized data models could support software and service designs. This paper introduces a model linking the domains of land administration and disaster risk management – with the goal of supporting resilience against natural disasters and providing an approach for collecting data once, and using it multiple times. A design approach was used to develop the model – with adaption of the international Land Administration Domain Model (LADM) standard acting as a basis. Key features of the model include the support of interoperability through standardisation, the inclusion of all people-to-land relationships including those specific to disaster contexts, and the potential of the model to contribute to each of the disaster phases. The model is suggested to be highly applicable in natural disaster contexts where no land tenure information exists or the national mapping authority already uses a land administration system compatible with LADM. Overall, the model is considered as a step toward an implementable strategy for applying responsible land administration in the context of disaster risk management

Output state in multiple entanglement swapping

The technique of quantum repeaters is a promising candidate for sending quantum states over long distances through a lossy channel. The usual discussions of this technique deals with only a finite dimensional Hilbert space. However the qubits with which one implements this procedure will "ride" on continuous degrees of freedom of the carrier particles. Here we analyze the action of quantum repeaters using a model based on pulsed parametric down conversion entanglement swapping. Our model contains some basic traits of a real experiment. We show that the state created, after the use of any number of parametric down converters in a series of entanglement swappings, is always an entangled (actually distillable) state, although of a different form than the one that is usually assumed. Furthermore, the output state always violates a Bell inequality.Comment: 11 pages, 6 figures, RevTeX

Comparison of weekly and daily recall of pain as an endpoint in a randomized phase 3 trial of cabozantinib for metastatic castration-resistant prostate cancer

Introduction: Scant evidence reveals whether the use of weekly versus daily pain ratings leads to meaningful differences when measuring pain as a clinical trial outcome. We compared the ability of weekly ratings and descriptors of daily ratings to evaluate pain as an endpoint in a randomized phase 3 drug trial. Methods: Participants (n = 119) with metastatic castration-resistant prostate cancer were randomized to treatment arms and rated their pain on the average and at its worst during a baseline week and at weeks 3, 6, and 12 of study treatment. For each reporting period, participants rated their pain daily for 7 days. On day 7, participants rated their pain over the prior 7 days. We estimated mean differences and intraclass correlation coefficients of the weekly ratings and the mean and the maximum daily ratings. We compared the ability of the weekly ratings and the daily rating descriptors to detect change in pain and evaluated the agreement of the weekly rating and the mean daily rating of pain at its worst to detect treatment response. Results: For both pain constructs, the weekly rating was consistently higher than the mean daily rating and lower than the maximum daily rating yet was moderately to highly correlated with both daily rating descriptors (intraclass correlation coefficient range = 0.55–0.94). The weekly rating and the daily rating descriptors consistently detected change in pain for the study sample and participant subgroups. Substantial agreement existed between the weekly rating and the mean daily rating of pain at its worst when used with trial protocol opioid criteria to detect treatment response (Cohen’s κ = 0.71). Conclusion: Use of daily over weekly ratings delivered no added benefit in evaluating pain in this clinical trial. This study is the first to compare weekly and daily recall to measure pain as an endpoint in a randomized phase 3 drug trial, and the pattern of differences in ratings that we observed is consistent with other recent evaluations of weekly and daily symptom reporting

Exponential lower bound on the highest fidelity achievable by quantum error-correcting codes

On a class of memoryless quantum channels which includes the depolarizing channel, the highest fidelity of quantum error-correcting codes of length n and rate R is proven to be lower bounded by 1-exp[-nE(R)+o(n)] for some function E(R). The E(R) is positive below some threshold R', which implies R' is a lower bound on the quantum capacity.Comment: Ver.4. In vers.1--3, I claimed Theorem 1 for general quantum channels. Now I claim this only for a slight generalization of depolarizing channel in this paper because Lemma 2 in vers.1--3 was wrong; the original general statement is proved in quant-ph/0112103. Ver.5. Text sectionalized. Appeared in PRA. The PRA article is typographically slightly crude: The LaTeX symbol star, used as superscripts, was capriciously replaced by the asterisk in several places after my proof readin

Creating resilience to natural disasters through FFP land administration – an application in Nepal

Information on people to land relationships - documented in a land administration system - is crucial in any natural disaster response. This work explores how Fit-For-Purpose approaches and interventions in Land Administration (FFP LA) can be used in the process of earthquake recovery, to improve the community resilience. Four affected communities from the April 2015 earthquake in the Dolakha district of Nepal are considered. The massive 7.6 magnitude earthquake struck Nepal on 25 April 2015 and was followed by subsequent aftershocks, larger than magnitude 4. Due to landslides, ruptures and destabilization almost five hundred settlements are considered in the need for relocation. The Nepal Government experiences problems in the recovery and reconstruction assistance to the earthquake victims. This concerned housing affected communities, especially people without any land documents. Therefore, innovative land tools are used in the post-earthquake context to support the recordation and management of customary and informal land rights for communities. A case study method is applied in three communities in the Dolakha region to see if such FFP LA approaches on the ground support rebuilding efforts. The FFP LA approach involved participatory mapping through and with the community by identifying visible boundaries on high-resolution satellite imagery. The approach is successful and proves to be efficient and effective mapping land rights in the context of Disaster Risk Management (DRM) – because urgently required data on people to land relationships for reconstruction grants and decision making are available quickly and with the agreement of the citizens. Information gathered by grassroot surveyors in the project area revealed that one third of the earthquake victims cannot access the grants because the land title is missing. Currently not all land rights are recognized nor recorded in the Land Administration System (LAS) in Nepal and this is delaying the post-disaster recovery and reconstruction processes. For this reason, tenure rights of the poor and vulnerable have to be secured and access to land has to be guaranteed. The Nepalese government reacted and developed a FFP LA strategy and also made changes in the requirements to access the reconstruction grants