660 research outputs found
Gradients of meteorological parameters in convective and nonconvective areas
Horizontal gradients of geopotential height, temperature, and wind speed were computed at the 850-, 700-, 500-, and 200-mb levels. Mixing ratio gradients also were computed, but only for the 850-, 700-, and 500-mb levels. Rawinsonde data was provided at 3- to 6-h intervals. Cumulative frequency distributions and statistical parameters showed that the variability and magnitude of the gradients decreased as the gradients were computed over progressively longer distances. Most frequency distributions were positively skewed, and the standard deviations of the gradient distributions were roughly half as large as the means. An examination of the differences of gradients observed in convective and nonconvective areas was made after convective areas were determined objectively using Manually Digitized Radar data. The gradients of height, wind speed, and mixing ratio at 850 mb were larger in convective than nonconvective areas. No general relationship held for the meteorological variables at other levels. Intensive examination of the gradients observed near squall lines revealed typical gradient patterns and trends in the magnitudes of the gradients associated with convective systems
An evaluation of the suitability of ERTS data for the purposes of petroleum exploration
This experiment was designed to determine the types and amounts of information valuable to petroleum exploration extractable from ERTS data and the cost of obtaining the information using traditional or conventional means. It was desired that an evaluation of this new petroleum exploration tool be made in a geologically well known area in order to assess its usefulness in an unknown area. The Anadarko Basin lies in western Oklahoma and the panhandle of Texas. It was chosen as a test site because there is a great deal of published information available on the surface and subsurface geology of the area, and there are many known structures that act as traps for hydrocarbons. This basin is similar to several other large epicontinental sedimentary basins. It was found that ERTS imagery is an excellent tool for reconnaissance exploration of large sedimentary basins or new exploration provinces. For the first time, small and medium size oil companies can rapidly and effectively analyze exploration provinces as a whole
Visual acuity screening in the preschool population: A comparison of two tests
Acuity measurement in adults is generally done with the Snellen acuity chart, however, acuity assessment in preschoolers must often utilize alternative methods. This study compared the Light House Acuity Test to the Broken Wheel Acuity Test to determine whether or not the Broken Wheel Acuity Test is a viable test for assessment of visual acuity in the preschool population in a screening situation. Results indicate that the tests have good correlation of acuity values and both procedures yielded high testability rates. Four year old children showed slower testing time than five year old children, but there was no significant difference in final acuity reached. Final choice of visual acuity screening tests should be based on individual responses of the child and on the individual preference of the examiner
Self-Presentational Determinants of Sex Differences in Leadership Behavior
Men and women placed in leadership positions communicated information about their skills and abilities to their subordinates. Although leaders’ perceptions of their abilities, group members’ knowledge of their leader’s abilities, and the specific skills needed by the leader were all manipulated in the experimental setting, self-presentations of ability were primarily determined by sex role stereotypes rather than by situational factors. Results indicated that (1) male leaders emphasized their social influence and task abilities; (2) female leaders emphasized their interpersonal, socioemotional abilities; and (3) group members felt task ability, as compared to interpersonal ability, was a far more important skill for a leader to possess. It was concluded that sex differences in male and female leadership behavior may be due to self-presentational conformity to sex roles, and that this conformity enhances males’ leadership effectiveness while detracting from females’ leadership effectiveness
Mechanistic and Functional Divergence Between Thyrotropin-releasing Hormone and RO 15-4513 Interactions with Ethanol
Both thyrotropin-releasing hormone (TRH) and RO 15-4513 antagonize ethanol-induced depression, but this common property does not infer that both compounds share similar mechanisms of action. In the present studies, both TRH (30 mg/kg, i.p.) and RO 15-4513 (10 mg/kg, i.p.) reversed ethanol-induced depression of locomotor activity, in accord with previous reports. However, the benzodiazepine antagonist, RO 15-1788, blocked this action of RO 15-4513, while exerting no effect on the analeptic action of TRH. Using a model of seizure activity electrically elicited from the inferior colliculus, ethanol exerted a dose-related attenuation of seizure activity. This anticonvulsant action of ethanol was not altered by TRH (30 mg/kg, i.p.), but RO 15-4513 (3 mg/kg) reversed the effect of the 0.5, but not the 1.0 g/kg, dose of ethanol. In addition, pretreatment with RO 15-4513 (1 or 3 mg/kg, i.p.), but not TRH (30 mg/kg, i.p.), caused seizure generalization into the forebrain following inferior collicular stimulation, further verifying the proconvulsant properties of RO 15-4513. In conclusion, the analeptic action of TRH appears independent of benzodiazepine activity, and in contrast to RO 15-4513, TRH does not exhibit proconvulsant properties. Furthermore, because TRH did not antagonize both depressant actions of ethanol studied, it appears unlikely that TRH directly interacts with the molecular basis of ethanol action
Singlet Glycine Riboswitches Bind Ligand as Well as Tandem Riboswitches
The glycine riboswitch often occurs in a tandem architecture, with two ligand-binding domains (aptamers) followed by a single expression platform. Based on previous observations, we hypothesized that singlet versions of the glycine riboswitch, which contain only one aptamer domain, are able to bind glycine if appropriate structural contacts are maintained. An initial alignment of 17 putative singlet riboswitches indicated that the single consensus aptamer domain is flanked by a conserved peripheral stem-loop structure. These singlets were sorted into two subtypes based on whether the active aptamer domain precedes or follows the peripheral stem-loop, and an example of each subtype of singlet riboswitch was characterized biochemically. The singlets possess glycine-binding affinities comparable to those of previously published tandem examples, and the conserved peripheral domains form A-minor interactions with the single aptamer domain that are necessary for ligand-binding activity. Analysis of sequenced genomes identified a significant number of singlet glycine riboswitches. Based on these observations, we propose an expanded model for glycine riboswitch gene control that includes singlet and tandem architectures
Structural Analysis of the Female Reptile Reproductive System by Micro-Computed Tomography and Optical Coherence Tomographyâ€
Volumetric data provide unprecedented structural insight to the reproductive tract and add vital anatomical context to the relationships between organs. The morphology of the female reproductive tract in non-avian reptiles varies between species, corresponding to a broad range of reproductive modes and providing valuable insight to comparative investigations of reproductive anatomy. However, reproductive studies in reptilian models, such as the brown anole studied here, have historically relied on histological methods to understand the anatomy. While these methods are highly effective for characterizing the cell types present in each organ, histological methods lose the 3D relationships between images and leave the architecture of the organ system poorly understood. We present the first comprehensive volumetric analyses of the female brown anole reproductive tract using two non-invasive, non-destructive imaging modalities: micro-computed tomography (microCT) and optical coherence tomography (OCT). Both are specialized imaging technologies that facilitate high-throughput imaging and preserve three-dimensional information. This study represents the first time that microCT has been used to study all reproductive organs in this species and the very first time that OCT has been applied to this species. We show how the non-destructive volumetric imaging provided by each modality reveals anatomical context including orientation and relationships between reproductive organs of the anole lizard. In addition to broad patterns of morphology, both imaging modalities provide the high resolution necessary to capture details and key anatomical features of each organ. We demonstrate that classic histological features can be appreciated within whole-organ architecture in volumetric imaging using microCT and OCT, providing the complementary information necessary to understand the relationships between tissues and organs in the reproductive system. This side-by-side imaging analysis using microCT and OCT allows us to evaluate the specific advantages and limitations of these two methods for the female reptile reproductive system
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