The Economic Impact of Invasive Species in the Ornamental Commodity in Puerto Rico: Towards Establishing a Multidimensional Framework for Data Collection and Analysis

The ornamental commodity in Puerto Rico is valued for its economic contribution in the agricultural sector, its contribution to the esthetics of natural scenarios that impact the tourism sector, and for its environmental role. In the fiscal year 2001, ornamentals generated 4.8% of the total Agricultural Gross Product. In that year the production value at farm level was $34.1 million, the export value$0.5 million, and the import value $11.5 millions. Of the local production value, 1.5% was exported and 34.3% of the ornamental local market value was imported. The active trade traffic in Puerto Rico is a factor that increases the risk of the introduction of invasive species that affect the agricultural sector. It is necessary to estimate the economic impact of the established invasive species and those with high potential for introduction. The economic analysis must consider the impact on production, on market, and on the environment. The direct and indirect impact on market and non-market areas has to be estimated. The study presented in this paper pretends to gather economic data on the ornamental commodity and biological data on invasive pests and diseases to initiate the development of a comprehensive species risk management framework that incorporates the economic impact of invasive species.invasive species, ornamental, economic impact analysis, Crop Production/Industries,

Nanometer-scale InGaAs Field-Effect Transistors for THz and CMOS technologies

Integrated circuits based on InGaAs Field Effect Transistors are currently in wide use in the RF front-ends of smart phones and other mobile platforms, wireless LANs, high data rate fiber-optic links and many defense and space communication systems. InGaAs ICs are also under intense research for new millimeter-wave applications such as collision avoidance radar and gigabit WLANs. InGaAs FET scaling has nearly reached the end of the road and further progress to propel this technology to the THz regime will require significant device innovations. Separately, as Si CMOS faces mounting difficulties to maintain its historical density scaling path, InGaAs-channel MOSFETs have recently emerged as a credible alternative for mainstream logic technology capable of scaling to the 10 nm node and below. To get to this point, fundamental technical problems had to be solved though there are still many challenges to be addressed before the first non-Si CMOS technology becomes a reality. The intense research that this exciting prospect is generating is also reinvigorating the prospects of InGaAs FETs to become the first true THz electronics technology. This paper reviews progress and challenges of InGaAs-based FET technology for THz and CMOS.Focus Center Research Program. Center for Materials, Structures and DevicesIntel CorporationUnited States. Army Research LaboratorySemiconductor Research Corporatio

The High-Electron Mobility Transistor at 30: Impressive Accomplishments and Exciting Prospects

2010 marked the 30th anniversary of the High-Electron Mobility Transistor (HEMT). The HEMT represented a triumph for the, at the time, relatively new concept of bandgap engineering and nascent molecular beam epitaxy technology. The HEMT showcased the outstanding electron transport characteristics of two-dimensional electron gas (2DEG) systems in III-V compound semiconductors. In the last 30 years, HEMTs have been demonstrated in several material systems, most notably AlGaAs/GaAs and AlGaN/GaN. Their uniqueness in terms of noise, power and high frequency operation has propelled HEMTs to gain insertion in a variety of systems where they provide critical performance value. 2DEG systems have also been a boon in solid-state physics where new and often bizarre phenomena have been discovered. As we look forward, HEMTs are uniquely positioned to expand the reach of electronics in communications, signal processing, electrical power management and imaging. Some of the most exciting prospects in the near future for HEMT-like devices are those of GaN for high voltage power management and III-V CMOS to give a new lease on life to Moore’s Law. This paper briefly reviews some highlights of HEMT development in the last 30 years in engineering and science. It also speculates about potential future applications

Variability in wheat: factors affecting its nutritional value

Wheat is a common raw material used to provide energy in broiler diets. Its apparent metabolisable energy and its influence on broiler performance varies between wheat samples. Reasons for that variability can be classified as intrinsic (variety, chemical composition) and extrinsic factors (growing conditions, storage, etc.), both of which affect nutrient digestibility and availability. However, these factors are not always considered when formulating the diets for broiler chickens. Moreover, research through the years has questioned the relation between wheat AME and animal performance. This review aims to describe factors that influence the observed variability in wheat nutritive value for broiler chickens by considering origin (variety, growing conditions and post-harvest storage), chemical composition of the grain (carbohydrates and protein) and the broiler chicken

Factors affecting wheat nutritional value for broiler chickens

In Europe, broiler chickens are fed with balanced diets where the energy is mainly supplied by wheat. The feed industry considers wheat a moderately uniform raw material and therefore its energy content and nutrient digestibility are taken from feeding tables (tabulated values) and assigned to all wheat grains. However, all major wheat-producing countries report considerable variability in energy content of wheat which invalidates the assumption of uniformity among wheat grains and forces the industry to look for the factors responsible of the variation. This PhD has focused on the study of factors that affect the nutritional value of wheat for broiler chickens. After the literature review, few nutrient components of the wheat grain (starch and non-starch polysaccharides) where selected and deeper studied in different wheat cultivars fed to broiler chickens. Emphasis was put on the rate of wheat starch digestion by broiler chickens and its effect on broiler performance

Time evolution of electrical degradation under high-voltage stress in GaN high electron mobility transistors

In this work, we investigate the time evolution of electrical degradation of GaN high electron mobility transistors under high voltage stress in the OFF state. We found that the gate current starts to degrade first, followed by degradation in current collapse and eventually permanent degradation in I[subscript D]. We also found that the time evolution of gate current degradation is unaffected by temperature, while drain current degradation is thermally accelerated

Hybrid modeling of renewable energy systems and its application to a hot water solar plant

IFAC - CONFERENCE ON CONTROL METHODOLOGIES AND TECHNOLOGY FOR ENERGY EFFICIENCY 29/03/2010 Vilamoura, PortugalA family of models that can be applied to various types of renewable energy plants is proposed. The methodology is used to model a solar plant for the production of sanitary water (the hot water production system installed at the “Hospital Universitario Virgen del Rocío”, Seville, Spain). A detailed examination of the behavior of the plant has produced a model which has served to identify niches of inefficiency in the operation. The model is later used to tune the parameters of a controller to improve operation.Ministerio de Ciencia y Tecnología DPI 2007-66718-C04-01Junta de Andalucía TEP-0272

Injection velocity in thin-channel InAs HEMTs

We have experimentally extracted the virtual-source electron injection velocity in InAs HEMTs with a 5 nm thick channel. For long gate lengths, these devices exhibit noticeably worse injection velocity than thicker channel devices of a similar design. However, for very short gate lengths, as the devices approach the ballistic regime, the extracted injection velocity becomes rather independent of channel thickness. From these results, we can conclude that InAs-based QW-FETs with very thin channels have the potential of scaling to very short dimensions.Intel CorporationSemiconductor Research Corporation. Center for Materials, Structures and Device

The prospects for 10 nm III-V CMOS

The increasing difficulties for further scaling down of Si CMOS is bringing to the fore the investigation of alternative channel materials. Among these, III-V compound semiconductors are very attractive due to their outstanding electron transport properties. This paper briefly reviews the prospects and the challenges for a III-V CMOS technology with gate lengths in the 10 nm range.Semiconductor Research CorporationIntel Corporatio