Characterization of distillability of entanglement in terms of positive maps

A necessary and sufficient condition for 1-distillability is formulated in terms of decomposable positive maps. As an application we provide insight into why all states violating the reduction criterion map are distillable and demonstrate how to construct such maps in a systematic way. We establish a connection between a number of existing results, which leads to an elementary proof for the characterisation of distillability in terms of 2-positive maps.Comment: 4 pages, revtex4. Published revised version, title changed, expanded discussion, main result unchange

Plant voedt bodem: Uit onderzoek blijkt dat planten belangrijker zijn voor het voeden van de bodem dan bemesting.

In de biologische landbouw wordt vaak gezegd dat je eerst de bodem moet voeden en dat zo vanzelf de plant wordt gevoed. Uit onderzoek komt echter steeds duidelijker naar voor dat de plant zelf een zeer belangrijke rol speelt bij het voeden van de bodem. Daarmee is de cyclus gewas>beworteling>bodemleven>bodem>gewas weer rond

Blocking entry of hepatitis B and D viruses to hepatocytes as a novel immunotherapy for treating chronic infections

Background. Chronic hepatitis B and D virus (HBV/HDV) infections can cause cancer. Current HBV therapy using nucleoside analogues (NAs) is life-long and reduces but does not eliminate the risk of cancer. A hallmark of chronic hepatitis B is a dysfunctional HBV-specific T-cell response. We therefore designed an immunotherapy driven by naive healthy T cells specific for the HDV antigen (HDAg) to bypass the need for HBV-specific T cells in order to prime PreS1-specific T cells and PreS1 antibodies blocking HBV entry. Methods. Ten combinations of PreS1 and/or HDAg sequences were evaluated for induction of PreS1 antibodies and HBV- and HDV-specific T cells in vitro and in vivo. Neutralization of HBV by PreS1-specific murine and rabbit antibodies was evaluated in cell culture, and rabbit anti-PreS1 were tested for neutralization of HBV in mice repopulated with human hepatocytes. Results. The best vaccine candidate induced T cells to PreS1 and HDAg, and PreS1 antibodies blocking HBV entry in vitro. Importantly, adoptive transfer of PreS1 antibodies prevented, or modulated, HBV infection after a subsequent challenge in humanized mice. Conclusions. We here describe a novel immunotherapy for chronic HBV/HDV that targets viral entry to complement NAs and coming therapies inhibiting viral maturation

MicroRNA MIR396 regulates the switch between stem cells and transit-amplifying cells in arabidopsis roots

To ensure an adequate organ mass, the daughters of stem cells progress through a transit-amplifying phase displaying rapid cell division cycles before differentiating. Here, we show that Arabidopsis thaliana microRNA miR396 regulates the transition of root stem cells into transit-amplifying cells by interacting with GROWTH-REGULATING FACTORs (GRFs). The GRFs are expressed in transit-amplifying cells but are excluded from the stem cells through inhibition by miR396. Inactivation of the GRFs increases the meristem size and induces periclinal formative divisions in transit-amplifying cells. The GRFs repress PLETHORA (PLT) genes, regulating their spatial expression gradient. Conversely, PLT activates MIR396 in the stem cells to repress the GRFs. We identified a pathway regulated by GRF transcription factors that represses stem cell-promoting genes in actively proliferating cells, which is essential for the progression of the cell cycle and the orientation of the cell division plane. If unchecked, the expression of the GRFs in the stem cell niche suppresses formative cell divisions and distorts the organization of the quiescent center. We propose that the interactions identified here between miR396 and GRF and PLT transcription factors are necessary to establish the boundary between the stem cell niche and the transit-amplifying region.Fil: Rodriguez Virasoro, Ramiro Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Ercoli, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Debernardi, Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Breakfield, Natalie W.. University of Duke; Estados UnidosFil: Mecchia, Martin Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Sabatini, Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; ArgentinaFil: Cools, Toon. University of Ghent; BélgicaFil: De Veylder, Lieven. University of Ghent; BélgicaFil: Benfey, Philip N.. University of Duke; Estados UnidosFil: Palatnik, Javier Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Biología Molecular y Celular de Rosario. Universidad Nacional de Rosario. Facultad de Ciencias Bioquímicas y Farmacéuticas. Instituto de Biología Molecular y Celular de Rosario; Argentin

Some Pieces Are Missing: Implicature Production in Children

Until at least 4 years of age, children, unlike adults, interpret some as compatible with all. The inability to draw the pragmatic inference leading to interpret some as not all, could be taken to indicate a delay in pragmatic abilities, despite evidence of other early pragmatic skills. However, little is known about how the production of these implicature develops. We conducted a corpus study on early production and perception of the scalar term some in British English. Children's utterances containing some were extracted from the dense corpora of five children aged 2;00 to 5;01 (N = 5,276), and analysed alongside a portion of their caregivers' utterances with some (N = 9,030). These were coded into structural and contextual categories allowing for judgments on the probability of a scalar implicature being intended. The findings indicate that children begin producing and interpreting implicatures in a pragmatic way during their third year of life, shortly after they first produce some. Their production of some implicatures is low but matches their parents' input in frequency. Interestingly, the mothers' production of implicatures also increases as a function of the children's age. The data suggest that as soon as they acquire some, children are fully competent in its production and mirror adult production. The contrast between the very early implicature production we find and the relatively late implicature comprehension established in the literature calls for an explanation; possibly in terms of the processing cost of implicature derivation. Additionally, some is multifaceted, and thus, implicatures are infrequent, and structurally and contextually constrained in both populations

Occurrence, distribution and diversity of Listeria monocytogenes contamination on beef and pig carcasses after slaughter

In this study we investigated the prevalence and location of Listeria monocytogenes and hygiene indicator bacteria on beef and pig carcasses. Carcasses were sampled after slaughter and before cooling at eight and nine sites on the carcass, respectively. For each sample, detection and enumeration of Listeria was performed, as well as the enumeration of Total Aerobic Counts (TAC) and Enterobacteriaceae. The L. monocytogenes isolates were also typed to determine pulsotypes and clonal complexes (CC). L. monocytogenes was detected on 46% [95% CI: 35-56%] of beef and 22% [95% CI: 11-32%] of pig carcasses. Contamination levels at the different carcass sites differed considerably between beef and pigs. Genetic typing of strains suggests that carcass contamination originates from both incoming animals with transmission during slaughter practices as well as persistent (CC9) contamination from the slaughterhouse environment. These findings can be used to understand the complexity of introduction and persistence of this pathogen in slaughter facilities. Accurate correlation of L. monocytogenes presence proved unfeasible with any of the tested hygiene indicator bacteria

Schmidt balls around the identity

Robustness measures as introduced by Vidal and Tarrach [PRA, 59, 141-155] quantify the extent to which entangled states remain entangled under mixing. Analogously, we introduce here the Schmidt robustness and the random Schmidt robustness. The latter notion is closely related to the construction of Schmidt balls around the identity. We analyse the situation for pure states and provide non-trivial upper and lower bounds. Upper bounds to the random Schmidt-2 robustness allow us to construct a particularly simple distillability criterion. We present two conjectures, the first one is related to the radius of inner balls around the identity in the convex set of Schmidt number n-states. We also conjecture a class of optimal Schmidt witnesses for pure states.Comment: 7 pages, 1 figur

Realization of logically labeled effective pure states for bulk quantum computation

We report the first use of "logical labeling" to perform a quantum computation with a room-temperature bulk system. This method entails the selection of a subsystem which behaves as if it were at zero temperature - except for a decrease in signal strength - conditioned upon the state of the remaining system. No averaging over differently prepared molecules is required. In order to test this concept, we execute a quantum search algorithm in a subspace of two nuclear spins, labeled by a third spin, using solution nuclear magnetic resonance (NMR), and employing a novel choice of reference frame to uncouple nuclei.Comment: PRL 83, 3085 (1999). Small changes made to improve readability and remove ambiguitie

Characterisation of a population of Pratylenchus hippeastri from bromeliads and description of two related new species, P. floridensis n. sp. and P. parafloridensis n. sp. from grasses in Florida

Morphological and molecular analyses confirmed the presence of P. hippeastri in regulatory samples collected in commercial bromeliad operations from genera Guzmania, Neoregelia and Vriesea in central and south Florida, USA. These P. hippeastri from bromeliads contained males which were not detected in the type population from amaryllis. The rDNA sequences of these males matched those of P. hippeastri female type material. Pratylenchus hippeastri and related root-lesion nematodes from several hosts in Florida were characterized at the morphological and molecular level, whereas other samples from Russia and South Africa at the molecular level only. Phylogenetic and sequence analysis using the ITS rRNA gene of these root-lesion nematodes revealed the presence of eight putative new species (spH1-H8) closely related to P. hippeastri. However, detailed morphological and molecular analyses are still required to confirm their unique species status. Here we describe two Florida representatives of the amphimictic root-lesion nematodes from Bahia grass (N1) and maidencane (N2), previously characterized by Inserra et al. (1996) and Duncan et al. (1999), as two new species phylogentically related to P. hippeastri and named Pratylenchus floridensis n. sp. and P. parafloridensis n. sp., respectively. The small round or oval, rarely rectangular and occasionally oblong and enlarged spermatheca and the bluntly pointed or subacute tail with smooth and occasionally indented terminus separate P. floridensis n. sp. from P. parafloridensis n. sp., which has a quadrangular spermatheca and a sub hemispherical or bluntly pointed tail with generally smooth and rarely indented terminus. However, these characters may overlap in some specimens making the morphological separation problematic without the use of molecular analysis. The close phylogenetic relationships shared by the species characterized in this study indicate that they are representatives of a P. hippeastri species complex