Eavesdropping on the "ping-pong" quantum communication protocol

The proposed eavesdropping scheme reveals that the quantum communication protocol recently presented by Bostrom and Felbinger [Phys. Rev. Lett. 89, 187902 (2002)] is not secure as far as quantum channel losses are taken into account

The ping-pong protocol can be attacked without eavesdropping

Attack the ping-pong protocol without eavesdropping.Comment: PACS: 03.67.H

The propagation of in-plane P-SV waves in a layered elastic plate with periodic interface cracks: exact versus spring boundary conditions

The propagation of in-plane (P-SV) waves in a symmetrically three-layered thick plate with a periodic array of interface cracks is investigated. The exact dispersion relation is derived based on an integral equation approach and Floquet's theorem. The interface cracks can be a model for interface damage, but a much simpler model is a recently developed spring boundary condition. This boundary condition is used for the thick plate and also in the derivation of plate equations with the help of power series expansions in the thickness coordinate. For low frequencies (cracks small compared to the wavelength) the three approaches give more or less coinciding dispersion curves, and this is a confirmation that the spring boundary condition is a reasonable approximation at low frequencies

The pure PV-EV energy system – A conceptual study of a nationwide energy system based solely on photovoltaics and electric vehicles

The objective of this conceptual study is to reveal the substantial potential and synergy of solar energy and electric vehicles (EVs) working together. This potential is demonstrated by studying the feasibility of a nationwide energy system solely reliant on solar energy and EVs. Photovoltaic (PV) solar energy is already an important energy source globally, but due to its intermittency it requires energy storage to balance between times of high and low production. At the same time, a global drive is underway in the transport sector: the change from internal combustion engines to EVs. Cars are in fact stationary 95% of the time, and when the vehicle is connected to the grid, the EV battery can regulate the intermittent PV source using vehicle-to-grid (V2G) technology. This paper presents a conceptual study of a pure PV-EV based energy system, with Spain as a case study. Provided that Spain’s entire fleet of 29.4 million road going vehicles is switched to EVs, the study shows that 3.45 billion m2 of PV (73 m2 per capita) could give Spain a completely self-reliant energy system. The theoretical study is based on a combination of measured values, simulations, and assumptions. The conclusion of the analysis is undoubtedly extraordinary, namely that an entire country like Spain can power its complete energy system solely on PV, using EVs as the only energy storage resource

Recursivity by Organizational Design: The Case of the Forest Stewardship Council

This article examines recursive processes in the Forest Stewardship Council (FSC), a nonstate forest standard-setting and accreditation organization. The FSC has developed numerous organizational structures and procedures that help it pool and analyze stakeholder input and feedback in standard-setting and implementation. We conceptualize recursive processes of stakeholder input and feedback and organizational responsiveness as recursivity by design. The article focuses on organizational legitimacy as a driver of recursive processes. The FSC's extensive participation procedures and structures present opportunities for incorporating stakeholder input and feedback in standard-setting and make it a responsive, legitimate, and effective governance scheme. It also enables the FSC to deal with challenges to its legitimacy and effectiveness. Whereas challenges associated with stakeholder participation and on-the-ground standard implementation are conceptualized in the literature as sources of organizational fragility and crisis, we argue that FSC's recursive structures help it accommodate criticism of and information about its performance and adjust its system to continuously emerging demands for more credibility and quality.1 Recursivity by organizational design: A conceptualization 2 The Forest Stewardship Council 3 The FSC's recursive standard-setting structures 4 Meta-standardization: The WTO and the ISEAL Alliance 5 Recursivity in implementation and quality assurance Conclusion

Comparative Expression Profiles of SUVH7 in Sexual and Apomict Boechera spp. Display Differential Expression

Genomic imprinting is parent-of-origin specific gene expression in embryo nourishing tissues endosperm and placenta in flowering plants and mammals, respectively. Seeds are formed with double fertilization in flowering plants and the endosperm has a 3n chromosome set with the contribution of 2 maternal and 1 paternal genome. Any deviation from this ratio (2m%2B1p) results in seed abortion in many species, however, apomict species modify their gametogenesis or fertilization to survive. Boechera divaricarpa is a diploid apomict plant species that can produce seeds with a 4m%253A1p parental genome ratio in endosperm and produce viable seeds. SUVH7, on the other hand, is a histone methyltransferase that has a catalytic SET domain responsible for epigenetic control of gene expression. In this study, we characterized the structures of the SUVH7 gene and compared the mRNA levels of SUVH7 in diploid apomict and sexual Boechera spp. in unopened immature buds and manually pollinated siliques representing the -pre and -post pollination stages, respectively. The expression level of SUVH7 in apomict B. divaricarpa has reached the max level 48 hours later following pollination, while in sexual B. stricta its expression level has dramatically decreased. Therefore, our study suggests the importance of epigenetic reprogramming in apomicts during seed development since chromatin marks via SUVH7 are commonly associated with the activation of transcription in plants

Chromosomal Evolution and Apomixis in the Cruciferous Tribe Boechereae

The mustard family (Brassicaceae) comprises several dozen monophyletic clades usually ranked as tribes. The tribe Boechereae plays a prominent role in plant research due to the incidence of apomixis and its close relationship to Arabidopsis. This tribe, largely confined to western North America, harbors nine genera and c. 130 species, with \u3e90% of species belonging to the genus Boechera. Hundreds of apomictic diploid and triploid Boechera hybrids have spurred interest in this genus, but the remaining Boechereae genomes remain virtually unstudied. Here we report on comparative genome structure of six genera (Borodinia, Cusickiella, Phoenicaulis, Polyctenium, Nevada, and Sandbergia) and three Boechera species as revealed by comparative chromosome painting (CCP). All analyzed taxa shared the same seven-chromosome genome structure. Comparisons with the sister Halimolobeae tribe (n = 8) showed that the ancestral Boechereae genome (n = 7) was derived from an older n = 8 genome by descending dysploidy followed by the divergence of extant Boechereae taxa. As tribal divergence post-dated the origin of four tribe-specific chromosomes, it is proposed that these chromosomal rearrangements were a key evolutionary innovation underlaying the origin and diversification of the Boechereae in North America. Although most Boechereae genera exhibit genomic conservatism, intra-tribal cladogenesis has occasionally been accompanied by chromosomal rearrangements (particularly inversions). Recently, apomixis was reported in the Boechereae genera Borodinia and Phoenicaulis. Here, we report sexual reproduction in diploid Nevada, diploid Sandbergia, and tetraploid Cusickiella and aposporous apomixis in tetraploids of Polyctenium and Sandbergia. In sum, apomixis is now known to occur in five of the nine Boechereae genera

Seasonal variations of PAHs content and distribution patterns in a mixed land use area: A case study in NE Italy with the transplanted lichen Pseudevernia furfuracea

The seasonal differences of the polycyclic aromatic hydrocarbons (PAHs) content in lichen transplants were investigated in an area of ca. 40 square kilometers in NE Italy characterized by different land use. Two sets of samples of the epiphytic lichen Pseudevernia furfuracea were collected in a pristine area of the Carnic Alps and transplanted to 40 exposure sites for a period of two months, respectively in late winter and in summer. Results revealed a pronounced difference between the two seasons in terms of PAH content and distribution patterns. After the summer exposure the PAH concentrations in the transplants were more than one order of magnitude lower than after the winter exposure (ranging from 48.22 to 272.73 ng g 121 dw and from 289.73 to 1575.85 ng g 121 dw in the summer and winter samples respectively). Also the main emission sources changed, mostly due to the drastic reduction in the emissions by wood burning for domestic heating and to the different meteorological conditions. In summer PAHs degradation was enhanced by intense UV radiation, high temperatures, and presence of ozone. The implications of these findings for the biomonitoring of PAHs pollution are addressed