3,036 research outputs found
Microwave detection of buried mines using non-contact, synthetic near-field focusing
Existing ground penetrating radars (GPR) are limited in their 3-D resolution. For the detection of buried land-mines, their performance is also seriously restricted by `clutter'. Previous work by the authors has concentrated on removing these limitations by employing multi-static synthetic focusing from a 2-D real aperture. This contribution presents this novel concept, describes the proposed implementation, examines the influence of clutter and of various ground features on the system's performance, and discusses such practicalities as digitisation and time-sharing of a single transmitter and receiver. Experimental results from a variety of scenarios are presented
New Additions to the Flora of San Nicolas Island, Ventura County, California
Ongoing collecting efforts on San Nicolas Island have substantially increased the number of plant species documented from the island. Here we report thirty-one plants previously unrecorded from the island. The list includes six eudicots, one monocot, four liverworts and twenty mosses. Five of these species are understood to be introduced on San Nicolas and the remainder are believed to be native. The native vascular plants are Logfia filaginoides, Cistanthe maritima and Muhlenbergia microsperma. Of the twenty-four new bryophytes, oneâAsterella bolanderiâis the first record from the Channel Islands. Specific ecological and locality information are provided for the new vascular plant finds and general patterns of bryophyte richness and ecological preferences are discussed
Measuring Intelligence with the Sandia Matrices: Psychometric Review and Recommendations for Free Raven-Like Item Sets
The Sandia Matrices are a free alternative to the Ravenâs Progressive Matrices (RPMs). This study offers a psychometric review of Sandia Matrices items focused on two of the most commonly investigated issues regarding the RPMs: (a) dimensionality and (b) sex differences. Model-data fit of three alternative factor structures are compared using confirmatory multidimensional item response theory (IRT) analyses, and measurement equivalence analyses are conducted to evaluate potential sex bias. Although results are somewhat inconclusive regarding factor structure, results do not show evidence of bias or mean differences by sex. Finally, although the Sandia Matrices software can generate infinite items, editing and validating items may be infeasible for many researchers. To aide implementation of the Sandia Matrices, we provide scoring materials for two brief static tests and a computer adaptive test. Implications and suggestions for future research using the Sandia Matrices are discussed
Bird nests as botanical time capsules: DNA barcoding identifies the contents of contemporary and historical nests
Bird nests in natural history collections are an abundant yet vastly underutilized source of genetic information. We sequenced the nuclear ribosomal internal transcribed spacer to identify plant species used as nest material in two contemporary (2003 and 2018) and two historical (both 1915) nest specimens constructed by Song Sparrows (Melospiza melodia) and Savannah Sparrows (Passerculus sandwichensis). A total of 13 (22%) samples yielded single, strong bands that could be identified using GenBank resources: six plants (Angiospermae), six green algae (Chlorophyta), and one ciliate (Ciliophora). Two native plant species identified in the nests included Festuca microstachys, which was introduced to the nest collection site by restoration practitioners, and Rosa californica, identified in a nest collected from a lost habitat that existed about 100 years ago. Successful sequencing was correlated with higher sample mass and DNA quality, suggesting future studies should select larger pieces of contiguous material from nests and materials that appear to have been fresh when incorporated into the nest. This molecular approach was used to distinguish plant species that were not visually identifiable, and did not require disassembling the nest specimens as is a traditional practice with nest material studies. The many thousands of nest specimens in natural history collections hold great promise as sources of genetic information to address myriad ecological questions
Rapid and Temporary Improvement of Depression and Anxiety Observed Following Niraparib Administration: A Case Report
Background: Cancer patients are disproportionately affected by generalized anxiety and major depression. For many, current treatments for these conditions are ineffective. In this case report, we present a serendipitous case of anxiety and depression improvement following administration of the poly (ADP-ribose) polymerase (PARP) inhibitor niraparib.
Case presentation: A 61-year old woman with a 20-year history of mild depression developed recurrent ovarian carcinoma and was placed on niraparib for maintenance chemotherapy. With the original onset of ovarian cancer, she experienced an episode of major depression that was resolved with sertraline. After recurrence of ovarian cancer, she experienced a recurrence of major depression and a new onset of generalized anxiety that failed to completely respond to multiple medications. After beginning niraparib therapy the patient noticed a rapid resolution of the symptoms of her anxiety and depression, an effect that was limited to 10-14 days. Due to bone marrow suppression, the patient was taken off and restarted on niraparib several times. Each discontinuation of niraparib resulted in return of her depression and anxiety, while each recontinuation of niraparib resulted in an improvement in her mood and anxiety.
Conclusions: This case demonstrates rapid and temporary improvement of anxiety and depression following niraparib administration. There is ample preclinical data that PARP signaling may play a role in psychiatric illness. A small amount of indirect data from clinical trials also shows that niraparib may have psychiatric benefits. Further research on PARP inhibition and its potential psychoactive effects is sorely needed
The effectiveness of preoperative rehabilitation programmes on postoperative outcomes following anterior cruciate ligament (ACL) reconstruction: a systematic review
Background: To explore the effectiveness of preoperative rehabilitation programmes (PreHab) on postoperative physical and psychological outcomes following anterior cruciate ligament reconstruction (ACLR). Method: A systematic search was conducted from inception to November 2019. Randomised controlled trials (RCTs) published in English were included. Risk of bias was assessed using Version 2 of the Cochrane risk-of-bias tool, and the Grading of Recommendations Assessment system was used to evaluate the quality of evidence. Results: The search identified 739 potentially eligible studies, three met the inclusion criteria. All included RCTs scored âhighâ risk of bias. PreHab in all three RCTs was an exercise programme, each varied in content (strength, control, balance and perturbation training), frequency (10 to 24 sessions) and length (3.1- to 6-weeks). Statistically significant differences (p < 0.05) were reported for quadriceps strength (one RCT) and single leg hop scores (two RCTs) in favour of PreHab three months after ACLR, compared to no PreHab. One RCT reported no statistically significant between-group difference for pain and function. No RCT evaluated post-operative psychological outcomes. Conclusion: Very low quality evidence suggests that PreHab that includes muscular strength, balance and perturbation training offers a small benefit to quadriceps strength and single leg hop scores three months after ACLR compared with no PreHab. There is no consensus on the optimum PreHab programme content, frequency and length. Further research is needed to develop PreHab programmes that consider psychosocial factors and the measurement of relevant post-operative outcomes such as psychological readiness and return to sport
Rendering volumetric haptic shapes in mid-air using ultrasound
We present a method for creating three-dimensional haptic shapes in mid-air using focused ultrasound. This approach applies the principles of acoustic radiation force, whereby the non-linear effects of sound produce forces on the skin which are strong enough to generate tactile sensations. This mid-air haptic feedback eliminates the need for any attachment of actuators or contact with physical devices. The user perceives a discernible haptic shape when the corresponding acoustic interference pattern is generated above a precisely controlled two-dimensional phased array of ultrasound transducers. In this paper, we outline our algorithm for controlling the volumetric distribution of the acoustic radiation force field in the form of a three-dimensional shape. We demonstrate how we create this acoustic radiation force field and how we interact with it. We then describe our implementation of the system and provide evidence from both visual and technical evaluations of its ability to render different shapes. We conclude with a subjective user evaluation to examine usersâ performance for different shapes
Machine Learning Prediction of Critical Cooling Rate for Metallic Glasses From Expanded Datasets and Elemental Features
We use a random forest model to predict the critical cooling rate (RC) for
glass formation of various alloys from features of their constituent elements.
The random forest model was trained on a database that integrates multiple
sources of direct and indirect RC data for metallic glasses to expand the
directly measured RC database of less than 100 values to a training set of over
2,000 values. The model error on 5-fold cross validation is 0.66 orders of
magnitude in K/s. The error on leave out one group cross validation on alloy
system groups is 0.59 log units in K/s when the target alloy constituents
appear more than 500 times in training data. Using this model, we make
predictions for the set of compositions with melt-spun glasses in the database,
and for the full set of quaternary alloys that have constituents which appear
more than 500 times in training data. These predictions identify a number of
potential new bulk metallic glass (BMG) systems for future study, but the model
is most useful for identification of alloy systems likely to contain good glass
formers, rather than detailed discovery of bulk glass composition regions
within known glassy systems
Euthanasia-related strain and coping strategies in animal shelter employees
ObjectiveâTo identify and evaluate coping strategies advocated by experienced animal shelter workers who directly engaged in euthanizing animals.
DesignâCross-sectional study.
Sample PopulationâAnimal shelters across the United States in which euthanasia was conducted (5 to 100 employees/shelter).
ProceduresâWith the assistance of experts associated with the Humane Society of the United States, the authors identified 88 animal shelters throughout the United States in which animal euthanasia was actively conducted and for which contact information regarding the shelter director was available. Staff at 62 animal shelters agreed to participate in the survey. Survey packets were mailed to the 62 shelter directors, who then distributed them to employees. The survey included questions regarding respondent age, level of education, and role and asked those directly involved in the euthanasia of animals to provide advice on strategies for new euthanasia technicians to deal with the related stress. Employees completed the survey and returned it by mail. Content analysis techniques were used to summarize survey responses.
ResultsâCoping strategies suggested by 242 euthanasia technicians were summarized into 26 distinct coping recommendations in 8 categories: competence or skills strategies, euthanasia behavioral strategies, cognitive or self-talk strategies, emotional regulation strategies, separation strategies, get-help strategies, seek long-term solution strategies, and withdrawal strategies.
Conclusions and Clinical RelevanceâEuthanizing animals is a major stressor for many animal shelter workers. Information regarding the coping strategies identified in this study may be useful for training new euthanasia technicians
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