Integration of electro-optical mechanical systems and medicine: Where are we and where can we go?

Microfabricated chip technologies offer researchers novel types of analysis of human clinical samples. Current examples of such technology include DNA amplification and analysis,and fluorescent cell analysis by flow cytometry. Potential applications include the development of rapid techniques for examining large numbers of cells in tissue or blood. This paper will outline criteria that successful devices must satisfy

Semiconductor microlasers with intracavity microfluidics for biomedical analyses

Recently demonstrated microfluidic chips have the potential to be useful bioanalytical tools for DNA, protein, and cellular studies. To realize this potential, means for introducing fluids, separating their components, and detection must be integrated onto the chip. The authors have investigated semiconductor laser microcavity spectroscopy as a means for ultrasensitive detection of various fluids, cells, and particulates. Two methods for implementing this laser device are illustrated. A scanning method for reading the light signals from a static fluid in the microcavity is presented. The device has a microfabricated flow structure formed between two surfaces, a vertical cavity surface-emitting laser and a glass dielectric mirror. The resonance frequencies of this Fabry-Perot microcavity are very sensitive to the dielectric properties of the fluids confined inside the cavity. Further, the resonance linewidth or cavity Q is sensitive to the optical length of the cavity, light absorption, and light scattering from the fluid and the surfaces forming the cavity. If cells or particulates are present in the fluid they confine light transverse to the cavity length and develop additional sub-frequencies between the Fabry-Perot frequencies. Thus, the spectrum of light emitted from or transmitted through the cavity comprises a wealth of information about the cavity contents

Inheritance of acid-soil tolerance in sorghum (\u3ci\u3eSorghum bicolor\u3c/i\u3e) grown on an Ultisol

Inheritance of acid-soil tolerance (generally considered AI-toxicity tolerance) i.n sorghum [Sorghum bicolor (L.) Moench] is not clear. Forty F1 sorghum hybrids and their 14 parents were grown two seasons in the field at relatively high (67 and 71%) and low (43 and 42%) Al saturations on an acid Ultisol in Colombia, South America to evaluate the effects of acid soil on agronomic component traits and to better understand inheritance of acid-soil tolerance of sorghum. For plants grown at the high Al saturation levels, hybrids from acid-soil tolerant [AS-T] x acid soil-sensitive [AS-S] crosses were as tolerant as hybrids from AS-T x AS-T crosses which were as tolerant as their AS-T parents. Hybrids from AS-S x AS-S crosses were all sensitive to the acid-soil stress conditions. General combining ability (GCA) and specific combining ability (SCA) effects were significant for acid-soil tolerance, and GCA effects were more important than SCA effects. Significant GCA and SCA effects were detected for grain yield and number of roots at the low Al saturation level. Additive genetic effects in these genotypes were important for acid-soil tolerance rating, grain yield, and number of roots at the high Al saturation level

Inheritance of acid-soil tolerance in sorghum (\u3ci\u3eSorghum bicolor\u3c/i\u3e) grown on an Ultisol

Inheritance of acid-soil tolerance (generally considered AI-toxicity tolerance) i.n sorghum [Sorghum bicolor (L.) Moench] is not clear. Forty F1 sorghum hybrids and their 14 parents were grown two seasons in the field at relatively high (67 and 71%) and low (43 and 42%) Al saturations on an acid Ultisol in Colombia, South America to evaluate the effects of acid soil on agronomic component traits and to better understand inheritance of acid-soil tolerance of sorghum. For plants grown at the high Al saturation levels, hybrids from acid-soil tolerant [AS-T] x acid soil-sensitive [AS-S] crosses were as tolerant as hybrids from AS-T x AS-T crosses which were as tolerant as their AS-T parents. Hybrids from AS-S x AS-S crosses were all sensitive to the acid-soil stress conditions. General combining ability (GCA) and specific combining ability (SCA) effects were significant for acid-soil tolerance, and GCA effects were more important than SCA effects. Significant GCA and SCA effects were detected for grain yield and number of roots at the low Al saturation level. Additive genetic effects in these genotypes were important for acid-soil tolerance rating, grain yield, and number of roots at the high Al saturation level

Genetic resistance to soil chemical toxicities and deficiencies.

Breeding new crop cultivars for adaptation to stress-related phenomena due to soil chemical toxicity and deficiency is a complex process. Data from nutrient culture trials, in which seedling plants are stressed with a deficiency or excess of mineral elements, do not correlate well with those from similar field stress conditions using the same germplasm. Further, evaluating segregating populations in nutrient culture can result in little or no genetic gain due to selection. Field screening efforts are plagued with genotype x environmental interactions caused by a multitude of biotic and abiotic factors. Selecting the proper level of stress for field evaluations and maintaining this level in a dynamically changeable medium like soil can be difficult. Genetic improvement of sorghum under field conditions similar to those encountered by farmers, however, has nearly always been obtained

Toward a user-centered design of a weather forecasting decision-support tool

Hazard Services is a software toolkit that integrates information management, hazard alerting, and communication functions into a single user interface. When complete, National Weather Service forecasters across the United States will use Hazard Services for operational issuance of weather and hydrologic alerts, making the system an instrumental part of the threat management process. As a new decision-support tool, incorporating an understanding of user requirements and behavior is an important part of building a system that is usable, allowing users to perform work-related tasks efficiently and effectively. This paper discusses the Hazard Services system and findings from a usability evaluation with a sample of end users. Usability evaluations are frequently used to support software and website development and can provide feedback on a system’s efficiency of use, effectiveness, and learnability. In the present study, a user-testing evaluation assessed task performance in terms of error rates, error types, response time, and subjective feedback from a questionnaire. A series of design recommendations was developed based on the evaluation’s findings. The recommendations not only further the design of Hazard Services, but they may also inform the designs of other decision-support tools used in weather and hydrologic forecasting. Incorporating usability evaluation into the iterative design of decision-support tools, such as Hazard Services, can improve system efficiency, effectiveness, and user experience

Effects of display design on signal detection in flash flood forecasting

The Flooded Locations and Simulated Hydrographs (FLASH) project is a suite of tools that use weather radar-based rainfall estimates to force hydrologic models to predict flash floods in real-time. However, early evaluation of FLASH tools in a series of simulated forecasting operations, it was believed that the data aggregation and visualization methods might have contributed to forecasting a large number of false alarms. The present study addresses the question of how two alternative data aggregation and visualization methods affect signal detection of flash floods. A sample of 30 participants viewed a series of stimuli created from FLASH images and were asked to judge whether or not they predicted significant or insignificant amounts of flash flooding. Analyses revealed that choice of aggregation method did affect probability of detection. Additional visual indicators such as geographic scale of the stimuli and threat level affected the odds of interpreting the model predictions correctly as well as congruence in responses between national and local scale model outputs

On positive solutions and the Omega limit set for a class of delay differential equations

This paper studies the positive solutions of a class of delay differential equations with two delays. These equations originate from the modeling of hematopoietic cell populations. We give a sufficient condition on the initial function for $t\leq 0$ such that the solution is positive for all time $t>0$. The condition is "optimal". We also discuss the long time behavior of these positive solutions through a dynamical system on the space of continuous functions. We give a characteristic description of the $\omega$ limit set of this dynamical system, which can provide informations about the long time behavior of positive solutions of the delay differential equation.Comment: 15 pages, 2 figure