Tunneling into a two-dimensional electron system in a strong magnetic field

We investigate the properties of the one-electron Green's function in an interacting two-dimensional electron system in a strong magnetic field, which describes an electron tunneling into such a system. From finite-size diagonalization, we find that its spectral weight is suppressed near zero energy, reaches a maximum at an energy of about $0.2e^{2}/\epsilon l_{c}$, and decays exponentially at higher energies. We propose a theoretical model to account for the low-energy behavior. For the case of Coulomb interactions between the electrons, at even-denominator filling factors such as $\nu=1/2$, we predict that the spectral weight varies as $e^{-\omega_0/|\omega|}$, for $\omega\rightarrow 0$

Data Sonification from the Desktop: Should Sound Be Part of Standard Data Analysis Software?

The design of auditory formats for data display is presently focused on applications for blind or visually impaired users, specialized displays for use when visual attention must be devoted to other tasks, and some innovative work in revealing properties of complex data that may not be effectively rendered by traditional visual means. With the availability of high-quality and flexible sound production hardware in standard desktop computers, the potential exists for using sound to represent characteristics of typical “small and simple” samples of data in routine data inspection and analysis. Our research has shown that basic properties of simple functions, distribution properties of data samples, and patterns of covariation between two variables can be effectively displayed by simple auditory graphs involving patterns of pitch variation over time. While such developments have implications for specialized applications and populations of users, these displays are easily comprehended by normal users with minimal practice. Providing further software enhancement to encourage exploration of data representation by sound may lead to a variety of useful creative developments in data display technology

Net Energy of Finishing Diets Containing Light or Normal Test Weight Corn

Net energy (NE) of diets containing 77.7% whole corn of either normal (53.8 Ib/bushel, NC) or light (40.8 Ib/bushel, LC) test weight was determined by total collection and indirect respiration calorimetry using six crossbred steers (avg wt 327 kg). Diet treatments were applied in a switchback design. The steers were initially adapted to ad libitum intake of either NC or LC diets for 32 days followed by 7 days total feces and urine collection. Gaseous exchange was subsequently measured for at least 48 hours. Intake was then reduced to an estimated 1.1 times maintenance for 6 days and collections were repeated. The steers were then switched between NC and LC diets and the entire process was repeated. As a percentage of gross energy consumed, fecal energy losses were 32% greater for the NC diet compared to LC (P\u3c .01). Urinary energy losses were unaffected by diet (P \u3e .20). Although energy lost as methane did not differ between diets at high intake, it was 27% greater for LC than NC at low intake (interaction P.20). Partial efficiencies of ME used for maintenance (k,) and gain (k,), as well as ME required for maintenance, also were not different (P\u3e.20). Diet NE for maintenance and gain was 13% greater for LC than NC. NE estimates calculated by difference for light and normal whole corn were 2.48, 1.65, 2.15 and 1.43 mcal/kg dry matter, respectively. These data demonstrate that corn of low test weight is not inherently lower in NE content than normal corn

Technician components and requirements model for the formation and management of cooperation networks among civil construction companies

A indústria da Construção Civil possui um modo de operação semelhante ao das organizações virtuais, mas de forma não estruturada, deixando de proporcionar vantagens competitivas. Para tanto, o artigo propõe um Modelo de Requisitos e Componentes Técnicos, baseado na metodologia EKD (Enterprise Knwoledge Development), para auxiliar a formação e gerência de redes entre empresas da construção civil. Para a elaboração do modelo proposto, foi conduzida uma análise dos projetos internacionais mais relevantes no setor da construção além de estudo de casos contendo sete obras a fim de detectar seus objetivos e pontos falhos a serem reestruturados e adaptados para a indústria da construção civil brasileira. Não obstante, o modelo proposto baseou-se em uma adaptação das melhores práticas de uma arquitetura de referência para redes. Como resultado, a proposição viabiliza uma visão clara dos requisitos necessários, explora a necessidade de intensa comunicação e troca de informações, além de contribuir com pesquisas futuras no que tange a um futuro desenvolvimento de sistema de informação direcionado para este segmento econômico.The operational method of civil construction can be analyzed by the outlook of virtual organizations, however not yet structuralized, hence not providing competitive advantages. Thus, this article considers a Technical Components and Requirements Model, based on EKD methodology (Enterprise Knowledge Development), to assist in the formation and management of networks in civil construction companies. For the elaboration of the considered model, an analysis of the most important international construction projects was conducted, in addition to a case study from seven construction projects in order to detect their goals and defective points, to then be reorganized and adapted to the Brazilian civil construction industry. Moreover, the considered model was also based on an adaptation of reference architecture for civil construction networks. As a result, the proposal makes possible, to the stakeholders, a clear view of the necessary requirements, exploring the necessity of intense communication and exchange of information, besides contributing to future research works regarding a future development of an information system directed for this economic segment

A scattering quantum circuit for measuring Bell's time inequality: a nuclear magnetic resonance demonstration using maximally mixed states

In 1985, Leggett and Garg (1985 Phys. Rev. Lett. 54 857) proposed a Bell-like inequality to test (in)compatibility between two fundamental concepts of quantum mechanics. The first concept is 'macroscopic realism', which is the quality of a physical property of a quantum system being independent of observation at the macroscopic level. The second concept is 'noninvasive measurability', which is the possibility of performing a measurement without disturbing the subsequent evolution of a system. One of the key requirement for testing the violation of the Leggett-Garg inequality, or Bell's time inequality, is the ability to perform noninvasive measurements over a qubit state. In this paper, we present a quantum scattering circuit that implements such a measurement for maximally mixed states. The operation of the circuit is demonstrated using liquid-state nuclear magnetic resonance (NMR) in chloroform, in which the time correlations of a qubit are measured on a probe (ancillary) qubit state. The results clearly show a violation region and are in excellent agreement with the predictions of quantum mechanics

Premelting of ice adsorbed on a rock surface

Considering ice-premelting on a quartz rock surface (i.e. silica) we calculate the Lifshitz excess pressures in a four layer system with rock–ice–water–air. Our calculations give excess pressures across (1) ice layer, (2) water layer, and (3) ice–water interface for different ice and water layer thicknesses. We analyse equilibrium conditions where the different excess pressures take zero value, stabilized in part by repulsive Lifshitz interactions. In contrast to previous investigations which considered varying thickness of only one layer (ice or water), here we present theory allowing for simultaneous variation of both layer thicknesses. For a given total thickness of ice and water, this allows multiple alternative equilibrium solutions. Consequently the final state of a system will depend on initial conditions and may explain variation in experimental measurements of the thicknesses of water and ice layers

Multidirectional Time-Dependent Effect of Sinigrin and Allyl Isothiocyanate on Metabolic Parameters in Rats

Sinigrin (SIN) and allyl isothiocyanate (AITC) are compounds found in high concentrations in Brassica family vegetables, especially in Brussels sprouts. Recently, they have been used as a nutrition supplement for their preventive and medicinal effect on some types of cancer and other diseases. In this research, nutritional significance of parent glucosinolate sinigrin 50 μmol/kg b. w./day and its degradation product allyl isothiocyanate 25 μmol/kg b. w./day and 50 μmol/kg b. w./day was studied by the evaluation of their influence on some parameters of carbohydrate and lipid metabolism in an animal rat model in vivo after their single (4 h) and 2 weeks oral administration. Additionally, the aim of this trial was to evaluate the direct action of AITC on basal and epinephrine-induced lipolysis in isolated rat adipocytes at concentration 1 μM, 10 μM and 100 μM in vitro. Sole AITC after 4 h of its ingestion caused liver triacylglycerols increment at both doses and glycaemia only at the higher dose. Multiple SIN treatment showed its putative bioconversion into AITC. It was found that SIN and AITC multiple administration in the same way strongly disturbed lipid and carbohydrate homeostasis, increasing esterified and total cholesterol, free fatty acids and lowering tracylglycerols in the blood serum. Additionally, AITC at both doses elevated insulinaemia and liver glycogen enhancement. The in vitro experiment revealed that AITC potentiated basal lipolysis process at 10 μM, and had stimulatory effect on epinephrine action at 1 μM and 10 μM. The results of this study demonstrated that the effect of SIN and AITC is multidirectional, indicating its impact on many organs like liver as well as pancreas, intestine in vivo action and rat adipocytes in vitro. Whilst consumption of cruciferous vegetables at levels currently considered “normal” seems to be beneficial to human health, this data suggest that any large increase in intake could conceivably lead to undesirable effect. This effect is potentiated with time of action of the examined compounds, whose influence is rather adverse for the majority of metabolic pathways (liver steatosis at short duration and insulinaemia, cholesterolaemia at long time treatment). Beneficial action of AITC concerned intensified hydrolysis of TG in the blood serum with a simultaneous lipolysis in adipocytes

Lipid droplets: a classic organelle with new outfits

Lipid droplets are depots of neutral lipids that exist virtually in any kind of cell. Recent studies have revealed that the lipid droplet is not a mere lipid blob, but a major contributor not only to lipid homeostasis but also to diverse cellular functions. Because of the unique structure as well as the functional importance in relation to obesity, steatosis, and other prevailing diseases, the lipid droplet is now reborn as a brand new organelle, attracting interests from researchers of many disciplines