Quantum-Noise Power Spectrum of Fields with Discrete Classical Components

We present an algorithmic approach to calculate the quantum-noise spectral density of photocurrents generated by optical fields with arbitrary discrete classical spectrum in coherent or squeezed states. The measurement scheme may include an arbitrary number of demodulations of the photocurrent. Thereby, our method is applicable to the general heterodyne detection scheme which is implemented in many experiments. For some of these experiments, e.g. in laser-interferometric gravitational-wave detectors, a reliable prediction of the quantum noise of fields in coherent and squeezed states plays a decisive role in the design phase and detector characterization. Still, our investigation is limited in two ways. First, we only consider coherent and squeezed states of the field and second, we demand that the photocurrent depends linearly on the field's vacuum amplitudes which means that at least one of the classical components is comparatively strong.Comment: 8 pages, 2 figure

Hybrid upper surface blown flap propulsive-lift concept for the quiet short-haul research aircraft

The hybrid upper surface blowing concept consists of wing-mounted turbofan engines with a major portion of the fan exhaust directed over the wing upper surface to provide high levels of propulsive lift, but with a portion of the fan airflow directed over selected portions of the airframe to provide boundary layer control. NASA-sponsored preliminary design studies identified the hybrid upper surface blowing concept as the best propulsive lift concept to be applied to the Quiet Short-Haul Research Aircraft (QSRA) that is planned as a flight facility to conduct flight research at low noise levels high approach lift coefficients, and steep approaches. Data from NASA in-house and NASA-sponsored small and large-scale wind tunnel tests of various configurations using this concept are presented

A preliminary investigation of trunk and wrist kinematics when using drivers with different shaft properties

It is unknown whether skilled golfers will modify their kinematics when using drivers of different shaft properties. This study aimed to firstly, determine if golf swing kinematics and swing parameters and related launch conditions differed when using modified drivers, then secondly, determine which kinematics were associated with clubhead speed. Twenty high level amateur male golfers (Mean ± SD: handicap = 1.9 ± 1.9 score) had their three-dimensional trunk and wrist kinematics collected for two driver trials. Swing parameters and related launch conditions were collected using a launch monitor. A one-way repeated measures ANOVA revealed significant (p ≤ 0.003) between-driver differences; specifically, faster trunk axial rotation velocity and an early wrist release for the low kick point driver. Launch angle was shown to be 2° lower for the high kick point driver. Regression models for both drivers explained a significant amount of variance (60 – 67%) in clubhead speed. Wrist kinematics were most associated with clubhead speed, indicating the importance of the wrists in producing clubhead speed regardless of driver shaft properties

Quiet propulsive lift for commuter airlines

The performance of STOL or RTOL aircraft and NASA's research program to provide options for future design and certification of quiet propulsive-life transports is described

An overview of the quiet short-haul research aircraft program

An overview of the Quiet Short Haul Research Aircraft (QSRA) Program is presented, with special emphasis on its propulsion and acoustic aspects. A description of the NASA technical participation in the program including wind tunnel testing, engine ground tests, and advanced aircraft simulation is given. The aircraft and its systems are described and, measured performance, where available, is compared to program goals. Preliminary data indicate that additional research and development are needed in some areas of which acoustics is an example. Some of these additional research areas and potential experiments using the QSRA to develop the technology are discussed. The concept of the QSRA as a national flight research facility is explained

Wind data from the 250-foot /76.2-meter/ tower at Wallops Island, Virginia

Statistical evaluation of sampled wind data from anemometers mounted on meteorological tower on Wallops Islan

LAND RIGHTS AND INTRA-HOUSEHOLD EMPLOYMENT AND RESOURCE USE IN THE PERI-URBAN AREA OF BANJUL, THE GAMBIA

As part of cooperative research program examining factor markets in peri-urban areas of The Gambia (Banjul and Serekunda) to see if they are constraining agricultural growth and employment, particularly in the horticultural subsector, the household production survey reported in this study assesses inter- and intrahousehold issues of market access and constraints to land-improving investment and productivity. Implemented in 1993, survey is highly disaggregated by plot, gender, enterprise, and type of employment.Land tenure--Gambia--Banjul Region, Vendors and purchasers--Gambia--Banjul Region, Household production--Gambia, Research methods, Rural conditions--Gambia, Rural off-farm employment--Gambia, Income and wealth--Gambia, Land markets--Gambia, Tenure types, Traditional--Gambia, Labor and Human Capital, Land Economics/Use,

LAND MARKETS AND LEGAL CONTRADICTIONS IN THE PERI-URBAN AREA OF ACCRA GHANA: INFORMANT INTERVIEWS AND SECONDARY DATA INVESTIGATIONS

The peri-urban area of Accra is experiencing a rapid transformation. A robust urban and agricultural land market has emerged, characterized by purchases, rapidly rising real land prices, and outsiders from Accra acquiring agricultural holdings for residential and commercial use. The fact that residences are being built, commercial firms are being established, and large firms are acquiring land for commercial interests attests to the ability of the customary system to enable transfers for productive activity. Nevertheless, limited or uncertain property rights increase investment costs and differential access to information in the land market affects equity. This paper seeks to better understand: (a) the land market in peri-urban Accra, (b) the process by which land held by indigenous communities is transferred to outsiders enabling the conversion of unoccupied or agricultural land into residential or commercial uses, and (c) the contradictions and frictions that exist at the interface of land transfers under customary and statutory systems. It further seeks to examine the possibility that uncertain property rights and high litigation costs are constraining commercial and agricultural investment, and to identify the economic and social factors that determine levels of premiums associated with transactions, and the duration of the customary allocation.Land tenure -- Ghana -- Accra Region, Land tenure -- Law and legislation - -Ghana, Land use, urban -- Ghana -- Accra Region, Real property -- Ghana -- Accra Region, Land reform -- Law and legislation -- Ghana, Land markets -- Ghana, Land tenure, urban -- Ghana, Land administration -- Law and legislation -- Ghana, Tenure types, Traditional -- Ghana, Research methods, Land Economics/Use,

Democratising food : the case for a deliberative approach

Prevailing political and ethical approaches that have been used to both critique and propose alternatives to the existing food system are lacking. Although food security, food sovereignty, food justice, and food democracy all offer something important to our reflection on the global food system, none is adequate as an alternative to the status quo. This article analyses each in order to identify the prerequisites for such an alternative approach to food governance. These include a focus on goods like nutrition and health, equitable distribution, supporting livelihoods, environmental sustainability, and social justice. However, other goods, like the interests of non-human animals, are not presently represented. Moreover, incorporating all of these goods is incredibly demanding, and some are in tension. This raises the question of how each can be appropriately accommodated and balanced. The article proposes that this ought to be done through deliberative democratic processes that incorporate the interests of all relevant parties at the local, national, regional, and global levels. In other words, the article calls for a deliberative approach to the democratisation of food. It also proposes that one promising potential for incorporating the interests of all affected parties and addressing power imbalances lies in organising the scope and remit of deliberation around food type

Using ultra-thin parylene films as an organic gate insulator in nanowire field-effect transistors

We report the development of nanowire field-effect transistors featuring an ultra-thin parylene film as a polymer gate insulator. The room temperature, gas-phase deposition of parylene is an attractive alternative to oxide insulators prepared at high temperatures using atomic layer deposition. We discuss our custom-built parylene deposition system, which is designed for reliable and controlled deposition of <100 nm thick parylene films on III-V nanowires standing vertically on a growth substrate or horizontally on a device substrate. The former case gives conformally-coated nanowires, which we used to produce functional $\Omega$-gate and gate-all-around structures. These give sub-threshold swings as low as 140 mV/dec and on/off ratios exceeding $10^3$ at room temperature. For the gate-all-around structure, we developed a novel fabrication strategy that overcomes some of the limitations with previous lateral wrap-gate nanowire transistors. Finally, we show that parylene can be deposited over chemically-treated nanowire surfaces; a feature generally not possible with oxides produced by atomic layer deposition due to the surface `self-cleaning' effect. Our results highlight the potential for parylene as an alternative ultra-thin insulator in nanoscale electronic devices more broadly, with potential applications extending into nanobioelectronics due to parylene's well-established biocompatible properties