5,790 research outputs found
Development and flight test of a helicopter compact, portable, precision landing system concept
An airborne, radar-based, precision approach concept is being developed and flight tested as a part of NASA's Rotorcraft All-Weather Operations Research Program. A transponder-based beacon landing system (BLS) applying state-of-the-art X-band radar technology and digital processing techniques, was built and is being flight tested to demonstrate the concept feasibility. The BLS airborne hardware consists of an add-on microprocessor, installed in conjunction with the aircraft weather/mapping radar, which analyzes the radar beacon receiver returns and determines range, localizer deviation, and glide-slope deviation. The ground station is an inexpensive, portable unit which can be quickly deployed at a landing site. Results from the flight test program show that the BLS concept has a significant potential for providing rotorcraft with low-cost, precision instrument approach capability in remote areas
Development Of An Engineered Bioluminescent Reporter Phage For Detection Of Bacterial Blight Of Crucifers
Bacterial blight, caused by the phytopathogen Pseudomonas cannabina pv. alisalensis, is an emerging disease afflicting important members of the Brassicaceae family. The disease is often misdiagnosed as pepper spot, a much less severe disease caused by the related pathogen Pseudomonas syringae pv. maculicola. We have developed a phage-based diagnostic that can both identify and detect the causative agent of bacterial blight and differentiate the two pathogens. A recombinant >light>-tagged reporter phage was generated by integrating bacterial luxAB genes encoding luciferase into the genome of P. cannabina pv. alisalensis phage PBSPCA1. The PBSPCA1::luxAB reporter phage is viable and stable and retains properties similar to those of the wildtype phage. PBSPCA1::luxAB rapidly and sensitively detects P. cannabina pv. alisalensis by conferring a bioluminescent signal response to cultured cells. Detection is dependent on cell viability. Other bacterial pathogens of Brassica species such as P. syringae pv. maculicola, Pseudomonas marginalis, Pectobacterium carotovorum, Xanthomonas campestris pv. campestris, and X. campestris pv. raphani either do not produce a response or produce significantly attenuated signals with the reporter phage. Importantly, the reporter phage detects P. cannabina pv. alisalensis on diseased plant specimens, indicating its potential for disease diagnosis.National Science Foundation Small Business Innovative Research 1012059U.S. Department of EducationU.S. Department of AgricultureCellular and Molecular Biolog
The inheritance of resistance to bacterial leaf spot of lettuce caused by Xanthomonas campestris pv. vitians in three lettuce cultivars.
Lettuce yields can be reduced by the disease bacterial leaf spot (BLS) caused by the pathogen Xanthomonas campestris pv. vitians (Xcv) and host resistance is the most feasible method to reduce disease losses. The cultivars La Brillante, Pavane and Little Gem express an incompatible host-pathogen interaction as a hypersensitive response (HR) to California strains of Xcv resulting in resistance. Little was known about the inheritance of resistance; however, resistance to other lettuce pathogens is often determined by resistance gene candidates (RGCs) encoding nucleotide-binding leucine-rich repeat (NB-LRR) proteins. Therefore, we determined the inheritance of BLS resistance in the cultivars La Brillante, Little Gem and Pavane and mapped it relative to RGCs. The reaction to Xcv was analyzed in nine F1, F2 and recombinant inbred line populations of lettuce from HR×compatible or HR×HR crosses. The HR in La Brillante, Pavane and Little Gem is conditioned by single dominant genes, which are either allelic or closely linked genes. The resistance gene in La Brillante was designated Xanthomonas resistance 1 (Xar1) and mapped to lettuce linkage group 2. Xar1 is present in a genomic region that contains numerous NB-LRR encoding RGCs and functional pathogen resistance loci in the RGC2 family. The Xar1 gene confers a high level of BLS resistance in the greenhouse and field that can be introgressed into commercial lettuce cultivars to reduce BLS losses using molecular markers
Who is the Practitioner in Faculty-Staff Sexual Misconduct Work?: Views from the UK and US
This article maps and compares four universities’ policies and procedures for addressing faculty and staff sexual misconduct in higher education in the UK and US. While universities have engaged in significant work to grapple with student-student sexual misconduct, attention to misconduct perpetrated, and experienced, by higher education employees is relatively nascent. In this paper, we explore the maze of institutional processes and actors that victim-survivors of FASSM might encounter. We describe what is known about prevalence of FASSM in the US and UK and offer an overview of the policy landscape in both settings. Inspired by Patricia Yancey Martin, we analyze publicly available policy documents on FASSM from two US and two UK universities and map out visually the range of investigative, reporting, and sanctioning processes. We introduce an analytic distinction between an actor and a practitioner within the FASSM context, whereby actors are those tasked with administrative duties in handling sexual misconduct reports, while practitioners are those with specialized knowledge and training that enables them to prioritize victim-survivor needs. These illustrative diagrams suggest that while university employees are tasked to act on reports and disclosures of sexual misconduct, it is difficult to identify specialist practitioners with expertise to support victim-survivors of FASSM. Ultimately, this work provides a deeper understanding of what practice looks like in relation to higher education FASSM, and we outline implications for future research directions
Preparing Family Caregivers to Recognize Delirium Symptoms in Older Adults After Elective Hip or Knee Arthroplasty
Objectives
To test the feasibility of a telephone-based intervention that prepares family caregivers to recognize delirium symptoms and how to communicate their observations to healthcare providers. Design
Mixed-method, pre–post quasi-experimental design. Setting
A Midwest Veterans Affairs Medical Center and a nonprofit health system. Participants
Forty-one family caregiver-older adult dyads provided consent; 34 completed the intervention. Intervention
Four telephone-based education modules using vignettes were completed during the 3 weeks before the older adult\u27s hospital admission for elective hip or knee replacement. Each module required 20 to 30 minutes. Measurements
Interviews were conducted before the intervention and 2 weeks and 2 months after the older adult\u27s hospitalization. A researcher completed the Confusion Assessment Method (CAM) and a family caregiver completed the Family Version of the Confusion Assessment Method (FAM-CAM) 2 days after surgery to assess the older adults for delirium symptoms. Results
Family caregivers’ knowledge of delirium symptoms improved significantly from before the intervention to 2 weeks after the intervention and was maintained after the older adult\u27s hospitalization. They also were able to recognize the presence and absence of delirium symptoms in the vignettes included in the intervention and in the older adult after surgery. In 94% of the cases, the family caregiver rating on the FAM-CAM approximately 2 days after the older adult\u27s surgery agreed with the researcher rating on the CAM. Family caregivers expressed satisfaction with the intervention and stated that the information was helpful. Conclusion
Delivery of a telephone-based intervention appears feasible. All family caregivers who began the program completed the four education modules. Future studies evaluating the effectiveness of the educational program should include a control group
Fault and magmatic interaction within Iceland's western rift over the last 9kyr
We present high-resolution 'Chirp' sub-bottom profiler data from Thingvallavatn, a lake in Iceland's western rift zone. These data are combined with stratigraphic constraints from sediment cores to show that movement on normal faults since 9 ka are temporally correlated with magmatic events, indicating that movements were controlled by episodic dyke intrusion. Sediment depo-centres and the focus of subsidence migrated westwards over 3-4 kyr towards the locus of subsequent brittle failure. We interpret this subsidence as related to dyke intrusion a few km along strike, originating from the Hengill volcanic system, which occurred prior to major dyking, faulting and subsidence within the lake at 1.9 ka
The Voluntary Adjustment of Railroad Obligations
Automatic memory management techniques eliminate many programming errors that are both hard to find and to correct. However, these techniques are not yet used in embedded systems with hard realtime applications. The reason is that current methods for automatic memory management have a number of drawbacks. The two major ones are: (1) not being able to always guarantee short real-time deadlines and (2) using large amounts of extra memory. Memory is usually a scarce resource in embedded applications. In this paper we present a new technique, Real-Time Reference Counting (RTRC) that overcomes the current problems and makes automatic memory management attractive also for hard real-time applications. The main contribution of RTRC is that often all memory can be used to store live objects. This should be compared to a memory overhead of about 500% for garbage collectors based on copying techniques and about 50% for garbage collectors based on mark-and-sweep techniques
Discrete and fuzzy dynamical genetic programming in the XCSF learning classifier system
A number of representation schemes have been presented for use within
learning classifier systems, ranging from binary encodings to neural networks.
This paper presents results from an investigation into using discrete and fuzzy
dynamical system representations within the XCSF learning classifier system. In
particular, asynchronous random Boolean networks are used to represent the
traditional condition-action production system rules in the discrete case and
asynchronous fuzzy logic networks in the continuous-valued case. It is shown
possible to use self-adaptive, open-ended evolution to design an ensemble of
such dynamical systems within XCSF to solve a number of well-known test
problems
Adubação foliar em tomateiro estaqueado. (Lycopersicum esculentum, mill). Santa Cruz - Kada.
Experimento realizado em solo latossol vermelho escuro-fase arenosa intergra de Terra roxa estruturada.Resumo
- …