Technion – Israel Institute of Technology

About: Technion – Israel Institute of Technology is a education organization based out in Haifa, Israel. It is known for research contribution in the topics: Population & Upper and lower bounds. The organization has 31714 authors who have published 79377 publications receiving 2603976 citations. The organization is also known as: Technion Israel Institute of Technology & Ṭekhniyon, Makhon ṭekhnologi le-Yiśraʼel.

Colloidal suspensions of clay or titanium dioxide nanoparticles can inhibit leaf growth and transpiration via physical effects on root water transport.

Abstract: A laboratory investigation was conducted to determine whether colloidal suspensions of inorganic nanoparticulate materials of natural or industrial origin in the external water supplied to the primary root of maize seedlings (Zea mays L.) could interfere with water transport and induce associated leaf responses. Water flow through excised roots was reduced, together with root hydraulic conductivity, within minutes of exposure to colloidal suspensions of naturally derived bentonite clay or industrially produced TiO2 nanoparticles. Similar nanoparticle additions to the hydroponic solution surrounding the primary root of intact seedlings rapidly inhibited leaf growth and transpiration. The reduced water availability caused by external nanoparticles and the associated leaf responses appeared to involve a rapid physical inhibition of apoplastic flow through nanosized root cell wall pores rather than toxic effects. Thus: (1) bentonite and TiO2 treatments also reduced the hydraulic conductivity of cell wall ghosts of killed roots left after hot alcohol disruption of the cell membranes; and (2) the average particle exclusion diameter of root cell wall pores was reduced from 6.6 to 3.0 nm by prior nanoparticle treatments. Irrigation of soil-grown plants with nanoparticle suspensions had mostly insignificant inhibitory effects on long-term shoot production, and a possible developmental adaptation is suggested.

Haem oxygenase is synthetically lethal with the tumour suppressor fumarate hydratase

Abstract: Fumarate hydratase (FH) is an enzyme of the tricarboxylic acid cycle (TCA cycle) that catalyses the hydration of fumarate into malate. Germline mutations of FH are responsible for hereditary leiomyomatosis and renal-cell cancer (HLRCC). It has previously been demonstrated that the absence of FH leads to the accumulation of fumarate, which activates hypoxia-inducible factors (HIFs) at normal oxygen tensions. However, so far no mechanism that explains the ability of cells to survive without a functional TCA cycle has been provided. Here we use newly characterized genetically modified kidney mouse cells in which Fh1 has been deleted, and apply a newly developed computer model of the metabolism of these cells to predict and experimentally validate a linear metabolic pathway beginning with glutamine uptake and ending with bilirubin excretion from Fh1-deficient cells. This pathway, which involves the biosynthesis and degradation of haem, enables Fh1-deficient cells to use the accumulated TCA cycle metabolites and permits partial mitochondrial NADH production. We predicted and confirmed that targeting this pathway would render Fh1-deficient cells non-viable, while sparing wild-type Fh1-containing cells. This work goes beyond identifying a metabolic pathway that is induced in Fh1-deficient cells to demonstrate that inhibition of haem oxygenation is synthetically lethal when combined with Fh1 deficiency, providing a new potential target for treating HLRCC patients.

Coherence in Large-Scale Networks: Dimension-Dependent Limitations of Local Feedback

Abstract: We consider distributed consensus and vehicular formation control problems. Specifically we address the question of whether local feedback is sufficient to maintain coherence in large-scale networks subject to stochastic disturbances. We define macroscopic performance measures which are global quantities that capture the notion of coherence; a notion of global order that quantifies how closely the formation resembles a solid object. We consider how these measures scale asymptotically with network size in the topologies of regular lattices in 1, 2, and higher dimensions, with vehicular platoons corresponding to the 1-D case. A common phenomenon appears where a higher spatial dimension implies a more favorable scaling of coherence measures, with a dimensions of 3 being necessary to achieve coherence in consensus and vehicular formations under certain conditions. In particular, we show that it is impossible to have large coherent 1-D vehicular platoons with only local feedback. We analyze these effects in terms of the underlying energetic modes of motion, showing that they take the form of large temporal and spatial scales resulting in an accordion-like motion of formations. A conclusion can be drawn that in low spatial dimensions, local feedback is unable to regulate large-scale disturbances, but it can in higher spatial dimensions. This phenomenon is distinct from, and unrelated to string instability issues which are commonly encountered in control problems for automated highways.

On information rates for mismatched decoders

Abstract: Reliable transmission over a discrete-time memoryless channel with a decoding metric that is not necessarily matched to the channel (mismatched decoding) is considered. It is assumed that the encoder knows both the true channel and the decoding metric. The lower bound on the highest achievable rate found by Csiszar and Korner (1981) and by Hui (1983) for DMC's, hereafter denoted C/sub LM/, is shown to bear some interesting information-theoretic meanings. The bound C/sub LM/ turns out to be the highest achievable rate in the random coding sense, namely, the random coding capacity for mismatched decoding. It is also demonstrated that the /spl epsiv/-capacity associated with mismatched decoding cannot exceed C/sub LM/. New bounds and some properties of C/sub LM/ are established and used to find relations to the generalized mutual information and to the generalized cutoff rate. The expression for C/sub LM/ is extended to a certain class of memoryless channels with continuous input and output alphabets, and is used to calculate C/sub LM/ explicitly for several examples of theoretical and practical interest. Finally, it is demonstrated that in contrast to the classical matched decoding case, here, under the mismatched decoding regime, the highest achievable rate depends on whether the performance criterion is the bit error rate or the message error probability and whether the coding strategy is deterministic or randomized. >

Observation of Associated Near-Side and Away-Side Long-Range Correlations in √sNN=5.02 TeV Proton-Lead Collisions with the ATLAS Detector

Abstract: Two-particle correlations in relative azimuthal angle (Delta phi) and pseudorapidity (Delta eta) are measured in root S-NN = 5.02 TeV p + Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1 mu b(-1) of data as a function of transverse momentum (p(T)) and the transverse energy (Sigma E-T(Pb)) summed over 3.1 < eta < 4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2 < vertical bar Delta eta vertical bar < 5) "near-side" (Delta phi similar to 0) correlation that grows rapidly with increasing Sigma E-T(Pb). A long-range "away-side" (Delta phi similar to pi) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small Sigma E-T(Pb), is found to match the near-side correlation in magnitude, shape (in Delta eta and Delta phi) and Sigma E-T(Pb) dependence. The resultant Delta phi correlation is approximately symmetric about pi/2, and is consistent with a dominant cos2 Delta phi modulation for all Sigma E-T(Pb) ranges and particle p(T).