Break-junction experiments on the zero-bias anomaly of non-magnetic and ferromagnetically ordered metals

We have investigated break junctions of normal non-magnetic metals as well as ferromagnets at low temperatures. The point contacts with radii 0.15 - 15 nm showed zero-bias anomalies which can be attributed to Kondo scattering at a single Kondo impurity at the contact or to the switching of a single conducting channel. The Kondo temperatures derived from the width of the anomalies varied between 10 and 1000 K. These results agree well with literature data on atomic-size contacts of the ferromagnets as well as with spear-anvil type contacts on a wide variety of metals.Comment: 7 pages, 4 figures, submitted to Proceedings of the 26th Conference on Low Temperature Physic

Spin polarization versus lifetime effects at point contacts between superconducting niobium and normal metals

Point-contact Andreev reflection spectroscopy is used to measure the spin polarization of metals but analysis of the spectra has encountered a number of serious challenges, one of which is the difficulty to distinguish the effects of spin polarization from those of the finite lifetime of Cooper pairs. We have recently confirmed the polarization-lifetime ambiguity for Nb-Co and Nb-Cu contacts and suggested to use Fermi surface mismatch, the normal reflection due to the difference of Fermi wave vectors of the two electrodes, to solve this dilemma. Here we present further experiments on contacts between superconducting Nb and the ferromagnets Fe and Ni as well as the noble metals Ag and Pt that support our previous results. Our data indicate that the Nb - normal metal interfaces have a transparency of up to about 80 per cent and a small, if not negligible, spin polarization.Comment: 7 pages, 2 figures, submitted to Proceedings of the 26th Conference on Low Temperature Physic

Animal Communication: Flies' Ears Are Tuned In

SummaryMale fruit flies sing to females with quiet, close-range wing vibrations. A new study has found that the flies' antennal ears show active tuning to the species-specific frequencies of songs

A genomic view of food-related and probiotic Enterococcus strains

The study of enterococcal genomes has grown considerably in recent years. While special attentionis paid to comparative genomic analysis among clinical relevant isolates, in this study we performedan exhaustive comparative analysis of enterococcal genomes of food origin and/or with potential tobe used as probiotics. Beyond common genetic features, we especially aimed to identify those thatare specific to enterococcal strains isolated from a certain food-related source as well as features presentin a species-specific manner. Thus, the genome sequences of 25 Enterococcus strains, from 7different species, were examined and compared. Their phylogenetic relationship was reconstructedbased on orthologous proteins and whole genomes. Likewise, markers associated with a successfulcolonization (bacteriocin genes and genomic islands) and genome plasticity (phages and clusteredregularly interspaced short palindromic repeats) were investigated for lifestyle specific genetic features.At the same time, a search for antibiotic resistance genes was carried out, since they are of bigconcern in the food industry. Finally, it was possible to locate 1617 FIGfam families as a core proteomeuniversally present among the genera and to determine that most of the accessory genes codefor hypothetical proteins, providing reasonable hints to support their functional characterization.Fil: Bonacina, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Suárez, Nadia Elina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Hormigo, Daniel Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Fadda, Silvina G.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; ArgentinaFil: Lechner, Marcus. University Marburg; AlemaniaFil: Saavedra, Maria Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Centro de Referencia Para Lactobacilos; Argentin

Phonon-drag induced suppression of the Andreev hole current in superconducting niobium contacts

We have investigated how the Andreev-reflection hole current at ballistic point contacts responds to a large bias voltage. Its strong suppression could be explained by the drag excerted by the non-equilibrium phonon wind generated by high-energy electrons flowing through the contact. The hole - phonon interaction leads to scattering lengths of the low-energetic holes down to 100\,nm, thereby destroying the coherent retracing of the electron path by the Andreev-reflected holes.Comment: 7 pages, 4 figures, submitted to Proceedings 26th International Conference on Low Temperature Physic

Prohibitin, an antiproliferative protein, is localized to mitochondria

AbstractProhibitin is a ubiquitously expressed protein with antiproliferative properties. When rat prohibitin tagged with a carboxy-terminal c-Myc epitope was expressed in baby hamster kidney cells the protein was targeted to mitochondria. In immunofluorescence microscopy prohibitin colocalized with a mitochondrial marker E3. Immunoelectron microscopy revealed that prohibitin was associated with the periphery of mitochondria. The amino-terminus of prohibitin shares characteristics of the known mitochondrial import signals, and positioning of the tag at the N-terminus causes accumulation of the protein in the cytoplasm. These findings help to direct functional studies on prohibitin and suggest that a mitochondrial protein may act as a tumor suppressor

Acquired phototrophy stabilizes coexistence and shapes intrinsic dynamics of an intraguild predator and its prey

Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by permission of John Wiley & Sons for personal use, not for redistribution. The definitive version was published in Ecology Letters 19 (2016): 393-402, doi:10.1111/ele.12572.In marine ecosystems, acquired phototrophs|organisms that obtain their photo- synthetic ability by hosting endosymbionts or stealing plastids from their prey|are omnipresent. Such taxa function as intraguild predators yet depend on their prey to periodically obtain chloroplasts. We present new theory for the effects of acquired phototrophy on community dynamics by analyzing a mathematical model of this predator-prey interaction and experimentally verifying its predictions with a lab- oratory model system. We show that acquired phototrophy stabilizes coexistence, but that the nature of this coexistence exhibits a `paradox of enrichment:' as light increases, the coexistence between the acquired phototroph and its prey transitions from a stable equilibrium to boom-bust cycles whose amplitude increases with light availability. In contrast, heterotrophs and mixotrophic acquired phototrophs (that obtain <30% of their carbon from photosynthesis) do not exhibit such cycles. This prediction matches eld observations, in which only strict (>95% of carbon from photosynthesis) acquired phototrophs form blooms.HVM is supported by a United States National Science Foundation Postdoctoral Research Fellowship in Biology (Grant No. DBI-1401332). EP is supported by the Academy of Finland through research grant 276268. MDJ acknowledges NSF Grant No. IOS-1354773. MGN acknowledges support provided by the Independent Research and Development Program at the Woods Hole Oceanographic Institution.2017-02-0

Surface state charge dynamics of a high-mobility three dimensional topological insulator

We present a magneto-optical study of the three-dimensional topological insulator, strained HgTe using a technique which capitalizes on advantages of time-domain spectroscopy to amplify the signal from the surface states. This measurement delivers valuable and precise information regarding the surface state dispersion within <1 meV of the Fermi level. The technique is highly suitable for the pursuit of the topological magnetoelectric effect and axion electrodynamics.Comment: Published version, online Sept 23, 201

Isolasi dan Karakterisasi Gen Pto Asal 20 Aksesi Anggrek Phalaenopsis

Bacterial soft rot disease because of Dickeya sp. infection is the main problem in Phalaenopsis production in Indonesia, but the percentage of infected plants has never been recorded in detail. Isolation and characterization of Pto gene from Phalaenopsis could be useful to support breeding for resistance Phalaenopsis. Encoding serine-threonine kinase, Pto gene confers resistance to bacterial infection of Pseudomonas syringae in tomato. The objectives of this study were to isolate, sequence and characterize fragment of Pto gene from 20 genotypes of Phalaenopsis (16 species and 4 hybrids) and to evaluate their molecular diversity. Genomic fragments of Phalaenopsis were amplified using Pto specific degenerate primers; and the PCR amplicons were sequenced. Searching the identity of determined sequences was done using BLAST against all accessions in NCBI GenBank DNA database and in Conserve Domain Database. PCR amplification using Pto specific primers produced a single DNA fragment of ~500 bp. The determined nucleotide sequences from the amplicon were ~449 bp. The nucleotide sequences of the amplicons from 20 Phalaenopsis genotypes showed high sequence identity to Pto from Musa acuminata. Translation of the amplicon results in ~149 amino acid residues. Comparison of the translated polypeptides identify indicated there were low variations of Pto gene among accessions since they contain the PTO catalytic domain and the Serine/Threonine kinases, sub family of Interleukin-1 Receptor Associated Kinase (STK_IRAK) which are the conserved domains for PTO