Hemodynamic responses to stellate ganglion stimulation in mongrels and greyhounds

A comparison of the effects of left stellate ganglion stimulation (SGS) on central and aortic hemodynamics has been made in chloralose-anesthetized mongrel (M), and greyhound (GH) dogs. Measurements of aortic pressure and flow, and left ventricular pressure were made during stimulation of the decentralized left SG at different frequencies from 0 to 20 Hz. The increases in aortic pressure and flow with SGS were larger in the GH, especially for low frequencies of stimulation. Stroke volume was increased with SGS in the GH at all stimulation rates, whereas in the M it was unchanged. A greater decrease in left ventricular end-diastolic pressure with SGS was found in the GH. These results suggest that differences exist in both the intrinsic and extrinsic control of cardiac output in the greyhound dog compared to the mongrel. These differences may be in part responsible for the elevated arterial blood pressure in the greyhound compared to the mongrel.     

A scattering matrix-based beamformer for wide-angle scanning in hybrid antennas

This paper presents a new approach to beamforming in hybrid antennas. Using a scattering matrix model for the hybrid antenna system, a bidirectional transformation is developed that relates the signals at the hybrid system feed to the signals that would be present in a planar array at the location of the reflector aperture. For example, the received fields at the feed of a hybrid antenna system may be transformed into the fields at the reflector aperture, and these reflector aperture fields may then be processed as if they were received by a planar or linear array. Similarly, the desired field or current distribution across the reflector aperture when transmitting may be transformed into the required field or current distribution at the hybrid system feed. This method allows standard linear or planar array analysis and synthesis techniques to be used with the hybrid system. Examples are provided for transmit and receive weight synthesis.     

New class of antioxidants

Antibiotics containing phenolic ‐OH groups, such as amoxicillin and cefadroxil, have been found to be strong antioxidants in common plastics to a much greater extent than would be guessed from their structures. Vancomycin, which contains several such groups, is also a powerful antioxidant. It is possible that this characteristic plays a part in inhibiting bacterial expression of counteragents such as β‐lactamases.     

Does adopted mean different? An attributional analysis.

46 adopted and 121 nonadopted Ss, aged 13–21 yrs and from upper-middle-class families, completed a series of attributional stories, Rotter's Internal–External Locus of Control Scale, and a perceived parenting questionnaire. Results indicate that attributions were different and that, contrary to expectations, adopted Ss were significantly more confident and viewed others more positively than nonadopted Ss. They also had a more internal locus of control than their nonadopted peers, and their adoptive parents were experienced as significantly more nurturant, comforting, predictable, protectively concerned, and helpful than were nonadoptive parents. It is suggested that an important correlate of attributional judgments is the parenting that is experienced. Results are discussed in terms of other studies that have reported an excessive number of adopted persons who have psychological problems. (51 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On the lower bound of the radiation Q for electrically small antennas

The fundamental question of the lower bound on the radiation Q of an electrically small antenna is of practical importance because of its relationship to the antenna bandwidth. Previous works predict a lower bound on the radiation Q that is usually too low and, hence, a bandwidth that can be optimistically large. This paper addresses why this is so and offers a new prediction for a realizable lower bound on the radiation Q. This new prediction is based on the far-field pattern, in both the visible and invisible spatial regions, in contrast to previous works based upon a near-field modal approach. Results for a linear dipole, bow-tie, and end-loaded dipole are presented to illustrate the validity of the lower bound presented herein. Radiation Q can be related to bandwidth provided the Q is adequately large. Implicit is the presence of a matching network as a part of the antenna system. Both the losses in the antenna and the losses in the matching network have an effect on the system bandwidth, the system efficiency and the system Q, of which the radiation Q is a part. These various relationships are also discussed.     

Spinal arteriovenous malformations

Spinal cord arteriovenous malformations encompass a variety of distinct lesions with aberrant connections between the arterial and venous circulation. Symptomatology and clinical presentation of such lesions are directly related to their location and particular pathophysiology. In the authors' surgical experience, 90% of patients have had the same or improved neurologic function and long-term follow-up.     

Training concurrent multistep procedural tasks

This study assessed the effectiveness of traditional whole-task, pure part-task, and two forward-chaining part-task techniques to train rapidly presented concurrent multistep tasks. When training was equated for the total number of training trials, the forward-chaining technique that included practice with concurrent responses promoted as much transfer to whole-task conditions as whole-task training and more than traditional pure part-task training. When training was equated for the total number of response opportunities, the same concurrent forward-chaining technique also promoted superior whole-task transfer. Actual or potential applications of this research include suggestions that trainers should (a) structure concurrent-task training around critical intratask invariants to promote whole-task transfer, (b) realize that the concurrent-task training techniques that promote the best training performance may not promote the best transfer to whole-task situations, and (c) consider using forward-chaining techniques that provide practice with concurrent responses when training concurrent multistep tasks.     

UAV Localization in Row Crops

High‐flying unmanned aerial vehicles (UAVs) are transforming industrial and research agriculture by delivering high spatiotemporal resolution data on a field environment. While current UAVs fly high above fields collecting aerial imagery, future low‐flying aircraft will directly interact with the environment and will utilize a wider variety of sensors. Safely and reliably operating close to unstructured environments requires improving UAVs' sensing, localization, and control algorithms. To this end, we investigate localizing a micro‐UAV in corn phenotyping trials using a laser scanner and IMU to control the altitude and position of the vehicle relative to the plant rows. In this process, the laser scanner is not only a means of localization, but also a scientific instrument for measuring plant properties. Experimental evaluations demonstrate that the is capable of safely and reliably operating in real‐world phenotyping trials. We experimentally validate the system in both low and high wind conditions in fully mature corn fields. Using test data from 18 test flights, we show that the UAV is capable of localizing its position to within one field row of the true position.