A Complementary Resistive Switch-based Crossbar Array Adder

Redox-based resistive switching devices (ReRAM) are an emerging class of non-volatile storage elements suited for nanoscale memory applications. In terms of logic operations, ReRAM devices were suggested to be used as programmable interconnects, large-scale look-up tables or for sequential logic operations. However, without additional selector devices these approaches are not suited for use in large scale nanocrossbar memory arrays, which is the preferred architecture for ReRAM devices due to the minimum area consumption. To overcome this issue for the sequential logic approach, we recently introduced a novel concept, which is suited for passive crossbar arrays using complementary resistive switches (CRSs). CRS cells offer two high resistive storage states, and thus, parasitic sneak currents are efficiently avoided. However, until now the CRS-based logic-in-memory approach was only shown to be able to perform basic Boolean logic operations using a single CRS cell. In this paper, we introduce two multi-bit adder schemes using the CRS-based logic-in-memory approach. We proof the concepts by means of SPICE simulations using a dynamical memristive device model of a ReRAM cell. Finally, we show the advantages of our novel adder concept in terms of step count and number of devices in comparison to a recently published adder approach, which applies the conventional ReRAM-based sequential logic concept introduced by Borghetti et al.Comment: 12 pages, accepted for IEEE Journal on Emerging and Selected Topics in Circuits and Systems (JETCAS), issue on Computing in Emerging Technologie

Suggested hurricane operational scenario for GOES I-M

Improvements in tropical cyclone forecasts require optimum use of remote sensing capabilities, because conventional data sources cannot provide the necessary spatial and temporal data density over tropical and subtropical oceanic regions. In 1989, the first of a series of geostationary weather satellites, GOES 1-M, will be launched with the capability for simultaneous imaging and sounding. Careful scheduling of the GOES 1-M will enable measurements of both the wind and mass fields over the entire tropical cyclone activity area. The document briefly describes the GOES 1-M imager and sounder, surveys the data needs for hurricane forecasting, discusses how geostationary satellite observations help to meet them, and proposes a GOES 1-M schedule of observations and hurricane relevant derived products

Asymmetric transmission of linearly polarized light at optical metamaterials

We experimentally demonstrate a three-dimensional chiral optical metamaterial that exhibits an asymmetric transmission for forwardly and backwardly propagating linearly polarized light. The observation of this novel effect requires a metamaterial composed of three-dimensional chiral metaatoms without any rotational symmetry. Our analysis is supported by a systematic investigation of the transmission matrices for arbitrarily complex, lossy media that allows deriving a simple criterion for asymmetric transmission in an arbitrary polarization base. Contrary to physical intuition, in general the polarization eigenstates in such three-dimensional and low-symmetry metamaterials do not obey fxed relations and the associated transmission matrices cannot be symmetrized

CYP35: Xenobiotically induced gene expression in the nematode Caenorhabditis elegans

Although over 80 cytochrome P450 (CYP) encoding genes have been identified in the genome of the nematode Caenorhabditis elegans very little is known about their involvement in biotransformation. This paper demonstrates a concentration-dependent relationship of C. elegans CYP35A1, A2, A5, and C1 gene expression in response to four organic xenobiotics, namely atrazine, PCB52, fluoranthene, and lansoprazole. The toxicity of these xenobiotics was determined using a reproduction assay. CYP-specific messenger RNA expression was analyzed by semi-quantitative RT-PCR resulting in a strongly increasing, concentration-dependent induction well below the EC50 for reproduction. For PCB52, approximately 0.5% of the EC50 induces a 2-fold increase of CYP35 gene expression. Using a double mutant and multiple RNAi of CYP35A/C it was possible to diminish the reproduction decline caused by PCB52 and fluoranthene.Peer Reviewe

Hidden quantum phase transition in Mn1−x_{1-x}Fex_{x}Ge: evidence brought by small-angle neutron scattering

The magnetic system of the Mn$_{1-x}$Fe$_{x}$Ge solid solution is ordered in a spiral spin structure in the whole concentration range of $x \in [0 \div 1]$. The close inspection of the small-angle neutron scattering data reveals the quantum phase transition from the long-range ordered (LRO) to short range ordered (SRO) helical structure upon increase of Fe-concentration at $x \in [0.25 \div 0.4]$. The SRO of the helical structure is identified as a Lorentzian contribution, while LRO is associated with the Gaussian contribution into the scattering profile function. The scenario of the quantum phase transition with $x$ as a driving parameter is similar to the thermal phase transition in pure MnGe. The quantum nature of the SRO is proved by the temperature independent correlation length of the helical structure at low and intermediate temperature ranges with remarkable decrease above certain temperature $T_Q$. We suggest the $x$-dependent modification of the effective Ruderman-Kittel-Kasuya-Yosida exchange interaction within the Heisenberg model of magnetism to explain the quantum critical regime in Mn$_{1-x}$Fe$_{x}$Ge.Comment: 6 pages, 4 figure

Overview of the Black Fungus Gnats from the Tristan da Cunha archipelago, including a redescription of Hyperlasion viridiventris (Frey) (Diptera: Sciaroidea: Sciaridae).

Auf den beiden Inseln Tristan da Cunha und Nightingale im Südatlantik wurden mit Malaisefallen Trauermücken (Diptera: Sciaridae) gesammelt. Im Ergebnis dessen konnten 4 Arten nachgewiesen werden, von denen Lycoriella sativae (Johannsen, 1912) aus der Literatur schon bekannt war. Drei andere – Bradysia tilicola (Loew, 1850), Hyperlasion viridiventris (Frey, 1945) und Pseudolycoriella setigera (Hardy, 1960) – werden zum ersten Mal von dem Archipel gemeldet. Zur Zeit sind 8 Spezies von der Inselgruppe bekannt. Diese gehören zu den Gattungen Bradysia Winnertz (3 Spezies), Cosmosciara Frey (1), Hyperlasion Schmitz (1), Lycoriella Frey (2) und Pseudolycoriella Menzel & Mohrig (1). Von den 7 namentlich bekannten Trauermücken-Arten des Archipels wurden die männlichen Genitalstrukturen abgebildet. Von Hyperlasion viridiventris (Frey) existierten bisher nur die schlecht erhaltenen Typ­exemplare von den Azoren. Auf der Basis des neuen Materials werden die Männchen und Weibchen redeskribiert. Außerdem wird eine Übersicht über die bis heute bekannt gewordenen Sciaridenfunde von der Inselgruppe gegeben. Die publizierten Funddaten wurden analysiert und mit den neuen Nachweisen verglichen.StichwörterDiptera, Sciaroidea, Sciaridae, Bradysia, Cosmosciara, Hyperlasion, Lycoriella, Pseudolycoriella, Afrotropical Region, South Atlantic, Tristan da Cunha archipelago, overview, distribution, redescription, new records.Black Fungus Gnats (Diptera: Sciaridae) were collected with Malaise traps on Tristan da Cunha and Nightingale islands in the South Atlantic. Four species were identified of which Lycoriella sativae (Johannsen, 1912) is already known from literature. For three others – Bradysia tilicola (Loew, 1850), Hyperlasion viridiventris (Frey, 1945) and Pseudolycoriella setigera (Hardy, 1960) – this is the first report from this archipelago. To date, 8 species are known from this group of islands. They belong to the genera Bradysia Winnertz (3 species), Cosmosciara Frey (1), Hyperlasion Schmitz (1), Lycoriella Frey (2) and Pseudolycoriella Menzel & Mohrig (1). The male genitalia for 7 particularly well known sciarid species from the archipelago are already illustrated but until now only poorly preserved type specimens of Hyperlasion viridiventris (Frey) from the Azores were known. Both male and female have been redescribed from the new material. An overview is also given of the existing sciarid records from the islands. The published data were analysed and compared with the new records.KeywordsDiptera, Sciaroidea, Sciaridae, Bradysia, Cosmosciara, Hyperlasion, Lycoriella, Pseudolycoriella, Afrotropical Region, South Atlantic, Tristan da Cunha archipelago, overview, distribution, redescription, new records

Dual-path state reconstruction scheme for propagating quantum microwaves and detector noise tomography

Quantum state reconstruction involves measurement devices that are usually described by idealized models, but not known in full detail in experiments. For weak propagating microwaves, the detection process requires linear amplifiers which obscure the signal with random noise. Here, we introduce a theory which nevertheless allows one to use these devices for measuring all quadrature moments of propagating quantum microwaves based on cross-correlations from a dual-path amplification setup. Simultaneously, the detector noise properties are determined, allowing for tomography. We demonstrate the feasibility of our novel concept by proof-of-principle experiments with classical mixtures of weak coherent microwaves.Comment: 11 pages, 3 figure