When Wnts antagonize Wnts

Secreted Wnt ligands appear to activate a variety of signaling pathways. Two papers in this issue now present genetic evidence that “noncanonical” Wnt signaling inhibits the “canonical” Wnt/β-catenin pathway. Westfall et al. (2003a) show that zebrafish embryos lacking maternal Wnt-5 function are dorsalized due to ectopic activation of β-catenin, whereas Topol et al. (2003) report that chondrogenesis in the distal mouse limb bud depends on inhibition of Wnt/β-catenin signaling by a paralogue of Wnt-5. These studies present the first genetic confirmation of the previous hypothesis that vertebrate Wnt signaling pathways can act in an antagonistic manner

Production, growth and properties of ultrafine atmospheric aerosol particles in an urban environment

Number concentrations of atmospheric aerosol particles were measured by a flow-switching type differential mobility particle sizer in an electrical mobility diameter range of 6–1000 nm in 30 channels near central Budapest with a time resolution of 10 min continuously from 3 November 2008 to 2 November 2009. Daily median number concentrations of particles varied from 3.8 × 10<sup>3</sup> to 29 ×10<sup>3</sup> cm<sup>−3</sup> with a yearly median of 11.8 × 10<sup>3</sup> cm<sup>−3</sup>. Contribution of ultrafine particles to the total particle number ranged from 58 to 92% with a mean ratio and standard deviation of (79 ± 6)%. Typical diurnal variation of the particle number concentration was related to the major emission patterns in cities, new particle formation, sinks of particles and meteorology. Shapes of the monthly mean number size distributions were similar to each other. Overall mean for the number median mobility diameter of the Aitken and accumulation modes were 26 and 93 nm, respectively, which are substantially smaller than for rural or background environments. The Aitken and accumulation modes contributed similarly to the total particle number concentrations at the actual measurement location. New particle formation and growth unambiguously occurred on 83 days, which represent 27% of all relevant days. Hence, new particle formation and growth are not rare phenomena in Budapest. Their frequency showed an apparent seasonal variation with a minimum of 7.3% in winter and a maximum of 44% in spring. New particle formation events were linked to increased gas-phase H<sub>2</sub>SO<sub>4</sub> concentrations. In the studied area, new particle formation is mainly affected by condensation sink and solar radiation. The formation process seems to be not sensitive to SO<sub>2</sub>, which was present in a yearly median concentration of 6.7 μg m<sup>−3</sup>. This suggests that the precursor gas was always available in excess. Formation rate of particles with a diameter of 6 nm varied between 1.65 and 12.5 cm<sup>−3</sup> s<sup>−1</sup> with a mean and standard deviation of (4.2 ± 2.5) cm<sup>−3</sup> s<sup>−1</sup>. Seasonal dependency for the formation rate could not be identified. Growth curves of nucleated particles were usually superimposed on the characteristic diurnal pattern of road traffic direct emissions. The growth rate of the nucleation mode with a median diameter of 6 nm varied from 2.0 to 13.3 nm h<sup>−1</sup> with a mean and standard deviation of (7.7 ± 2.4) nm h<sup>−1</sup>. There was an indicative tendency for larger growth rates in summer and for smaller values in winter. New particle formation events increased the total number concentration by a mean factor and standard deviation of 2.3 ± 1.1 relative to the concentration that occurred immediately before the event. Several indirect evidences suggest that the new particle formation events occurred at least over the whole city, and were of regional type. The results and conclusions presented are the first information of this kind for the region over one-year long time period

Social Conformity in Autism

Humans are extremely susceptible to social influence. Here, we examine whether this susceptibility is altered in autism, a condition characterized by social difficulties. Autistic participants (N=22) and neurotypical controls (N=22) completed a memory test of previously seen words and were then exposed to answers supposedly given by four other individuals. Autistic individuals and controls were as likely to alter their judgements to align with inaccurate responses of group members. These changes reflected both temporary judgement changes (public conformity) and long-lasting memory changes (private conformity). Both groups were more susceptible to answers believed to be from other humans than from computer algorithms. Our results suggest that autistic individuals and controls are equally susceptible to social influence when reporting their memories

Collapse-revivals and population trapping in the m-photon mazer

We present a study of collapse-revival patterns that appear in the changes of atomic populations induced by the interaction of ultracold two-level atoms with electromagnetic cavities in resonance with an $m$-photon transition of the atoms ($m$-photon mazer). In particular, sech$^2$ and gaussian cavity mode profiles are considered and differences in the collapse-revival patterns are reported. The quantum theory of the $m$-photon mazer is written in the framework of the dressed-state coordinate formalism. Simple expressions for the atomic populations, the cavity photon statistics, and the reflection and transmission probabilities are given for any initial state of the atom-field system. Evidence for the population trapping phenomenon which suppress the collapse-revivals in the $m$-photon mazer is given.Comment: 9 revtex pages including 4 postscript figures. Submitted for publicatio

Symmetric qubits from cavity states

Two-mode cavities can be prepared in quantum states which represent symmetric multi-qubit states. However, the qubits are impossible to address individually and as such cannot be independently measured or otherwise manipulated. We propose two related schemes to coherently transfer the qubits which the cavity state represents onto individual atoms, so that the qubits can then be processed individually. In particular, our scheme can be combined with the quantum cloning scheme of Simon and coworkers [C. Simon et al, PRL 84, 2993 (2000)] to allow the optimal clones which their scheme produces to be spatially separated and individually utilized.Comment: 8 pages, 4 figures, minor typographical errors correcte

A Granulysin-Derived Peptide with Potent Activity against Intracellular Mycobacterium tuberculosis

Granulysin is an antimicrobial peptide (AMP) expressed by human T-lymphocytes and natural killer cells. Despite a remarkably broad antimicrobial spectrum, its implementation into clinical practice has been hampered by its large size and off-target effects. To circumvent these limitations, we synthesized a 29 amino acid fragment within the putative cytolytic site of Granulysin (termed “Gran1”). We evaluated the antimicrobial activity of Gran1 against the major human pathogen Mycobacterium tuberculosis (Mtb) and a panel of clinically relevant non-tuberculous mycobacteria which are notoriously difficult to treat. Gran1 efficiently inhibited the mycobacterial proliferation in the low micro molar range. Super-resolution fluorescence microscopy and scanning electron microscopy indicated that Gran1 interacts with the surface of Mtb, causing lethal distortions of the cell wall. Importantly, Gran1 showed no off-target effects (cytokine release, chemotaxis, cell death) in primary human cells or zebrafish embryos (cytotoxicity, developmental toxicity, neurotoxicity, cardiotoxicity). Gran1 was selectively internalized by macrophages, the major host cell of Mtb, and restricted the proliferation of the pathogen. Our results demonstrate that the hypothesis-driven design of AMPs is a powerful approach for the identification of small bioactive compounds with specific antimicrobial activity. Gran1 is a promising component for the design of AMP-containing nanoparticles with selective activity and favorable pharmacokinetics to be pushed forward into experimental in vivo models of infectious diseases, most notably tuberculosis

Weak lensing analysis of RXC J2248.7-4431

We present a weak lensing analysis of the cluster of galaxies RXC J2248.7-4431, a massive system at z=0.3475 with prominent strong lensing features covered by the HST/CLASH survey (Postman et al. 2012). Based on UBVRIZ imaging from the WFI camera at the MPG/ESO-2.2m telescope, we measure photometric redshifts and shapes of background galaxies. The cluster is detected as a mass peak at 5sigma significance. Its density can be parametrised as an NFW profile (Navarro et al. 1996) with two free parameters, the mass M_200m=(33.1+9.6-6.8)x10^14Msol and concentration c_200m=2.6+1.5-1.0. We discover a second cluster inside the field of view at a photometric redshift of z~0.6, with an NFW mass of M_200m=(4.0+3.7-2.6)x10^14Msol.Comment: 15 pages, 17 figures; matching published versio

Source apportionment of carbonaceous chemical species to fossil fuel combustion, biomass burning and biogenic emissions by a coupled radiocarbon-levoglucosan marker method

An intensive aerosol measurement and sample collection campaign was conducted in central Budapest in a mild winter for 2 weeks. The online instruments included an FDMS-TEOM, RT-OC/EC analyser, DMPS, gas pollutant analysers and meteorological sensors. The aerosol samples were collected on quartz fibre filters by a low-volume sampler using the tandem filter method. Elemental carbon (EC), organic carbon (OC), levoglucosan, mannosan, galactosan, arabitol and mannitol were determined, and radiocarbon analysis was performed on the aerosol samples. Median atmospheric concentrations of EC, OC and PM2.5 mass were 0.97, 4.9 and 25 mu g m(-3), respectively. The EC and organic matter (1.6 x OC) accounted for 4.8 and 37 %, respectively, of the PM2.5 mass. Fossil fuel (FF) combustion represented 36% of the total carbon (TC = EC + OC) in the PM2.5 size fraction. Biomass burning (BB) was a major source (40 %) for the OC in the PM2.5 size fraction, and a substantial source (11 %) for the PM10 mass. We propose and apply here a novel, straightforward, coupled radiocarbon-levoglucosan marker method for source apportionment of the major carbonaceous chemical species. The contributions of EC and OC from FF combustion (ECFF and OCFF to the TC were 11.0 and 25 %, respectively, EC and OC from BB (ECBB and OCBB were responsible for 5.8 and 34 %, respectively, of the TC, while the OC from biogenic sources (OCBIO made up 24% of the TC. The overall relative uncertainty of the OCBIO and OCBB contributions was assessed to be up to 30 %, while the relative uncertainty for the other apportioned species is expected to be below 20 %. Evaluation of the apportioned atmospheric concentrations revealed some of their important properties and relationships among them. ECFF and OCFF were associated with different FF combustion sources. Most ECFF was emitted by vehicular road traffic, while the contribution of non-vehicular sources such as domestic and industrial heating or cooking using gas, oil or coal to OCFF was substantial. The mean contribution of BB to EC particles was smaller by a factor of approximately 2 than that of road traffic. The main formation processes of OCFF, OCBB and OCBIO from volatile organic compounds were jointly influenced by a common factor, which is most likely the atmospheric photochemistry, while primary organic emissions can also be important. Technological improvements and control measures for various BB appliances, together with efficient education and training of their users, in particular on the admissible fuel types, offer an important potential for improving the air quality in Budapest, and likely in other cities as well

Universal Continuous Variable Quantum Computation in the Micromaser

We present universal continuous variable quantum computation (CVQC) in the micromaser. With a brief history as motivation we present the background theory and define universal CVQC. We then show how to generate a set of operations in the micromaser which can be used to achieve universal CVQC. It then follows that the micromaser is a potential architecture for CVQC but our proof is easily adaptable to other potential physical systems.Comment: 12 pages, 4 figures, accepted for a presentation at the 9th International Conference on Unconventional Computation (UC10) and LNCS proceedings

High-T_c Superconductivity with T_c = 52 K under Antiferromagnetic Order in Five-layered Cuprate Ba_2Ca_4Cu_5O_10(F,O)_2 with T_N = 175 K: 19F- and Cu-NMR Studies

We report on the observation of high-T_c superconductivity (SC) emerging with the background of an antiferromagnetic (AFM) order in the five-layered cuprate Ba_2Ca_4Cu_5O_10(F,O)_2 through 19F-NMR and zero-field Cu-NMR studies. The measurements of spectrum and nuclear spin-lattice relaxation rates 19(1/T_1) of 19F-NMR give convincing evidence for the AFM order taking place below T_N = 175 K and for the onset of SC below T_c = 52 K, hence both coexisting. The zero-field Cu-NMR study has revealed that AFM moments at Cu sites are 0.14 mu_B at outer CuO_2 layers and 0.20 mu_B at inner ones. We remark that an intimate coupling exists between the AFM state and the SC order parameter below T_c = 52 K; the spin alignment in the AFM state is presumably changed in the SC-AFM mixed state.Comment: 4 pages, 4 figures, to be published in Journal of the Physical Society of Japan, Vol.80, No.