Linking leaf initiation to the aerial environment: when air temperature is not the whole story

The initiation of new leaves, which takes place at the shoot apical meristem, is essential for plant growth and development. Leaf initiation rate (LIR) is very sensitive to meristem temperature. However, in practice meristem temperature is hardly ever monitored and air temperature is often used instead. It can be questioned whether relating LIR solely to air temperature is valid. This thesis aims at linking LIR to the aerial environment in two main horticultural crops: tomato and cucumber. It was shown that meristem temperature often differs from air temperature, depending on other environmental factors (e.g. radiation, humidity and wind speed) and species-specific traits. LIR was solely influenced by meristem temperature even when it largely deviated from air temperature. In addition, LIR was reduced at low light levels. Consequently, air temperature is not the whole story when relating leaf initiation to the environment. </p

Localizability of Wireless Sensor Networks: Beyond Wheel Extension

A network is called localizable if the positions of all the nodes of the network can be computed uniquely. If a network is localizable and embedded in plane with generic configuration, the positions of the nodes may be computed uniquely in finite time. Therefore, identifying localizable networks is an important function. If the complete information about the network is available at a single place, localizability can be tested in polynomial time. In a distributed environment, networks with trilateration orderings (popular in real applications) and wheel extensions (a specific class of localizable networks) embedded in plane can be identified by existing techniques. We propose a distributed technique which efficiently identifies a larger class of localizable networks. This class covers both trilateration and wheel extensions. In reality, exact distance is almost impossible or costly. The proposed algorithm based only on connectivity information. It requires no distance information

Enhancing Biometric-Capsule-based Authentication and Facial Recognition via Deep Learning

In recent years, developers have used the proliferation of biometric sensors in smart devices, along with recent advances in deep learning, to implement an array of biometrics-based authentication systems. Though these systems demonstrate remarkable performance and have seen wide acceptance, they present unique and pressing security and privacy concerns. One proposed method which addresses these concerns is the elegant, fusion-based BioCapsule method. The BioCapsule method is provably secure, privacy-preserving, cancellable and flexible in its secure feature fusion design. In this work, we extend BioCapsule to face-based recognition. Moreover, we incorporate state-of-art deep learning techniques into a BioCapsule-based facial authentication system to further enhance secure recognition accuracy. We compare the performance of an underlying recognition system to the performance of the BioCapsule-embedded system in order to demonstrate the minimal effects of the BioCapsule scheme on underlying system performance. We also demonstrate that the BioCapsule scheme outperforms or performs as well as many other proposed secure biometric techniques

Red and Blue Light Effects during Growth on Hydraulic and Stomatal Conductance in Leaves of Young Cucumber Plants

Many horticultural crops (food and ornamental) are produced year-round in greenhouses at high latitudes, where the limited availability of natural sunlight restricts plant production during large parts of the year. To enable year-round plant production supplemental light is necessary to enhance photosynthesis, the primary process that drives growth and production. It is therefore not surprising that during the last two decades most of the research effort related to light in greenhouse horticulture has been directed towards optimizing the supplemental light use efficiency for photosynthesis, with emphasis on light intensity, duration and since recently also on light quality. For a long time, high pressure sodium (HPS) lamps were the preferred lamps for supplemental lighting. Nowadays, Light Emitting Diodes (LEDs) are gaining importance, mostly because of their potentially higher energy efficiency. Another important, less-well known attribute of LEDs is the much better possibility to control light quality. Besides the effect on photosynthesis, light quality also influences plant morphological and developmental processes, mostly mediated by a set of blue, red and far-red photoreceptors (i.e., cryptochromes, phototropins and phytochromes). Several of these processes, such as for instance internode and petiole elongation growth and leaf expansion have a direct impact on productivity via plant photosynthesis as mediated by light interception. Light quality can also induce leaf deformations and epinasty, which can negatively influence biomass production via reduced light interception. In ornamental crops, such as chrysanthemum, leaf deformations can have severe negative impact on the final ornamental value. Other important effects of light quality involve the development of stomatal density and the control of stomatal aperture, which both attribute to stomatal conductance and therefore potentially influence productivity, while also the leaf hydraulic resistance is influenced by light quality. This paper will overview some plant morphological and developmental processes that are influenced by light quality and are important for plant production in protected environments

Density of States and Conductivity of Granular Metal or Array of Quantum Dots

The conductivity of a granular metal or an array of quantum dots usually has the temperature dependence associated with variable range hopping within the soft Coulomb gap of density of states. This is difficult to explain because neutral dots have a hard charging gap at the Fermi level. We show that uncontrolled or intentional doping of the insulator around dots by donors leads to random charging of dots and finite bare density of states at the Fermi level. Then Coulomb interactions between electrons of distant dots results in the a soft Coulomb gap. We show that in a sparse array of dots the bare density of states oscillates as a function of concentration of donors and causes periodic changes in the temperature dependence of conductivity. In a dense array of dots the bare density of states is totally smeared if there are several donors per dot in the insulator.Comment: 13 pages, 15 figures. Some misprints are fixed. Some figures are dropped. Some small changes are given to improve the organizatio

Longitudinal and transversal piezoresistive response of granular metals

In this paper, we study the piezoresistive response and its anisotropy for a bond percolation model of granular metals. Both effective medium results and numerical Monte Carlo calculations of finite simple cubic networks show that the piezoresistive anisotropy is a strongly dependent function of bond probability p and of bond conductance distribution width \Delta g. We find that piezoresistive anisotropy is strongly suppressed as p is reduced and/or \Delta g is enhanced and that it vanishes at the percolation thresold p=p_c. We argue that a measurement of the piezoresistive anisotropy could be a sensitive tool to estimate critical metallic concentrations in real granular metals.Comment: 14 pages, 7 eps figure

Phonon and Elastic Instabilities in MoC and MoN

We present several results related to the instability of MoC and MoN in the B1 (sodium chloride) structure. These compounds were proposed as potential superconductors with moderately high transition temperatures. We show that the elastic instability in B1-structure MoN, demonstrated several years ago, persists at elevated pressures, thus offering little hope of stabilizing this material without chemical doping. For MoC, another material for which stoichiometric fabrication in the B1-structure has not proven possible, we find that all of the cubic elastic constants are positive, indicating elastic stability. Instead, we find X-point phonon instabilities in MoC (and in MoN as well), further illustrating the rich behavior of carbo-nitride materials. We also present additional electronic structure results for several transition metal (Zr, Nb and Mo) carbo-nitride systems and discuss systematic trends in the properties of these materials. Deviations from strict electron counting dependencies are apparent.Comment: 5 pages and 4 trailing figures. Submitted to PR