223 research outputs found
Arm Flexion, Arm Extension, and Motivational Responses to Feared Stimuli
People are highly motivated to approach attractive stimuli and to avoid noxious stimuli (e.g., Lang, Bradley, & Cuthbert, 1990; Schneirla, 1959. Approach of attractive stimuli (e.g., obtaining food, pursuit of sexual relations) and avoidance of noxious stimuli (e.g., defense against predatory threat) ensure continued survival, a basic goal of all living organisms. And yet, sometimes approach/avoidance behavior is maladaptive. For instance, individuals with intense fears of spiders experience strong avoidance motivation in spite of the relative harmlessness of most spiders.
The research reported here evaluated whether a simple, easily executed bodily manipulation can dampen the strong avoidance motivation that typically results when a person is exposed to cues of a feared stimulus (e.g., Hamm, Cuthbert, Globisch, & Vaitl, 1997). Previous research in our laboratory (Thibodeau, 2011) and others (e.g., Cacioppo, Priester, & Berntson, 1993) suggests that the execution of simple actions normally associated with approach behavior (e.g., arm flexion, as when pulling attractive objects near) is sufficient, by itself, to elicit approach motivation. The current research explored whether spider- and snake-fearful undergraduates and non-fearful controls who were exposed to photographs of fear-relevant stimuli could diminish the size and strength of avoidance motives simply by concurrently engaging in an approach-related action. The startle probe (Lang et al., 1990) was used to index the strength of participants’ avoidance motives.
METHOD
Forty undergraduates participated in the study for course credit. Fearful participants (n = 24) obtained scores above 20 on self-report questionnaires measuring snake or spider fear (Klorman, Weerts, Hastings, Melamed, & Lang, 1974); controls (n = 16) obtained scores below 6.
The startle reflex was indexed by electromyographic (EMG) recording of the orbicularis oculi (“blink”) muscle, contraction of which causes the sudden closure of the eyelids that represents a key element of the startle response. Participants viewed a series of 45 pictures (15 spiders or snakes, 15 household objects, 15 fixation crosses) and concurrently performed arm flexion (an approach action), arm extension (an avoidance action), or squeezed the edge of a table (a neutral control action); all pictures and actions were presented in a quasi-randomized sequence. Bursts of 50-ms white noise (98 dB) were unpredictably presented to elicit the startle reflex. We followed standard procedures for the reduction and scoring of startle data (Blumenthal et al., 2005).
RESULTS AND DISCUSSION
Contrary to predictions, the motivational actions were not related to the size of the startle reflex (Action main effect; p = .27). This pattern held for both groups (Action x Group interaction; p = .17), and it was not moderated by Picture Type (Action x Picture Type interaction; p = .90). The three-way interaction was also nonsignificant (p = .15). Importantly, however, a significant main effect of Picture Type (F[2,76] = 7.03, p = .002) confirmed a previously documented pattern of heightened startle reactivity during viewing of fear-relevant pictures (e.g., Hamm et al., 1997). Overall, the present data suggest that the motivational actions utilized here (Cacioppo et al., 1993; Thibodeau, 2011) are insufficient to moderate avoidance-related emotional responses to feared stimuli
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Effects of fine sediments and substrate size on growth of juvenile coho salmon in laboratory streams
Terrapin technologies manned Mars mission proposal
A Manned Mars Mission (M3) design study is proposed. The purpose of M3 is to transport 10 personnel and a habitat with all required support systems and supplies from low Earth orbit (LEO) to the surface of Mars and, after an eight-man surface expedition of 3 months, to return the personnel safely to LEO. The proposed hardware design is based on systems and components of demonstrated high capability and reliability. The mission design builds on past mission experience, but incorporates innovative design approaches to achieve mission priorities. Those priorities, in decreasing order of importance, are safety, reliability, minimum personnel transfer time, minimum weight, and minimum cost. The design demonstrates the feasibility and flexibility of a Waverider transfer module
Molecular characterization of the genes encoding the tungsten-containing aldehyde ferredoxin oxidoreductase from Pyrococcus furiosus and formaldehyde ferredoxin oxidoreductase from Thermococcus litoralis
The hyperthermophilic archaea Pyrococcus furiosus and Thermococcus litoralis contain the tungstoenzymes aldehyde ferredoxin oxidoreductase, a homodimer, and formaldehyde ferredoxin oxidoreductase, a homotetramer. herein we report the cloning and sequencing of the P. furiosus gene aor (605 residues; M_r, 66,630) and the T. litoralis gene for (621 residues; M_r, 68,941)
Characteristics of Diverse Breeds in Cycle IV of the Cattle Germ Plasm Evaluation Program at the U.S. Meat Animal Research Center
Breed differences in performance characteristics are an important genetic resource for improving efficiency of beef production. Diverse breeds are required to exploit heterosis and complementarity through crossbreeding and new composite breeds and to match genetic potential with diverse markets, feed resources and climates. This report presents preliminary results from an ongoing study at the Roman L. Hruska U.S. Meat Animal Research Center (MARC) to characterize breeds of cattle representing diverse biological types for traits that influence quantity and value of production
Germ Plasm Evaluation Program- Progress Report No. 12
Breed differences in performance characteristics are an important genetic resource for improving efficiency of beef production. Diverse breeds are required to exploit heterosis and complementarity through crossbreeding and to match genetic potential with diverse markets, feed resources and climates. This report presents preliminary results from an ongoing study at the Roman L. Hruska U.S. Meat Animal Research Center to characterize breeds of cattle representing different biological types for traits that influence quantity and value of production.
Experimental Procedure:
The Germ Plasm Evaluation (GPE) program has been conducted in four cycles. Table 1 shows the mating plan for cycles I, II, III, and IV. Each cycle was initiated by mating Hereford and Angus cows by artificial insemination (AI) to sires of diverse breeds. Semen from the same Hereford and Angus bulls has been used throughout to produce control Hereford-Angus (original HAx, sires born 1968-70) reciprocal crosses in each cycle. In cycle IV, new samples of Hereford and Angus (current HAx, sires born 1982-84) bulls were added to evaluate genetic trends within these breeds. In cycle IV, semen from 14 original control Angus, 11 original control Hereford, 30 current Angus, 32 current Hereford (14 horned and 18 polled), 29 Longhorn, 24 Piedmontese, 31 Charolais, 29 Salers, 31 Galloway, 22 Nel1ore, and 26 Shorthorn bulls is being used by AI to produce about 200 calves per sire breed in five calf crops (1986-1990). Following an AI period of about 45 days, one or two bulls each of Angus, Hereford, Charolais, Gelbvieh, and Pinzgauer bulls are used each year by natural service in single-sire breeding pastures for about 21 days. These breeds are being used in clean-up matings to increase ties to previous cycles and facilitate eventual pooling of results over all four cycles
Breeding for Lean Beef (Germ Plasm Evaluation Program)
Historically, when steers were finished on pasture, ability to finish at a young age was desirable, particularly when market requirements for fatness were great. However, ability to fatten became a handicap as we shifted to increased use of concentrate feeds in diets of growing-finishing cattle. Consequently, yield grades were added to the USDA grading system to reflect variation in carcass value associated with differences in yield of retail product. Recently, consumer pressure to reduce caloric and fat content of beef and other red meats has intensified because coronary heart disease is believed to be associated with elevated blood-cholesterol levels. Cholesterol levels are, in turn, associated with dietary intake of saturated fat. Dietary control of the type and amount of fat consumed is strongly recommended by members of the medical profession in an attempt to regulate blood-cholesterol levels. The purpose of this paper is to examine genetic variation among and within breeds in the amount and distribution of fat and lean in beef carcasses and to evaluate opportunities to genetically change fat and caloric content of retail product in cattle
Gait Recognition Using Encodings With Flexible Similarity Measures
Gait signals detectable by sensors on ubiquitous personal devices such as smartphones can reveal characteristics unique to each individual, and thereby offer a new approach to recognizing users. Conventional pattern matching approaches use inner-product based distance measures which are not robust to common variations in time-series analysis (e.g., shifts and stretching). This is unfortunate given that it is well understood that capturing such variations is paramount for model performance. This work shows how machine learning methods which encode gait signals into a feature space based on a dictionary can use convolution and Dynamic TimeWarping (DTW) similarity measures to improve classification accuracy in a variety of situations common to gait recognition. We also show that data augmentation is crucial in gait recognition, as diverse training data in practical applications is very limited. We validate the effectiveness of these methods empirically, and demonstrate the identification of user gait patterns where shift and stretch variations in measurements are substantial. We present a new gait dataset that contains a complete representation of the variations that can be expected in real-world recognition scenarios. We compare our techniques against the current state of the art gait period detection and normalization schemes on our dataset and show improved classification accuracy under all experimental scenarios.Engineering and Applied Science
Bayesian Analysis for Remote Biosignature Identification on exoEarths (BARBIE) II: Using Grid-Based Nested Sampling in Coronagraphy Observation Simulations for O2 and O3
We present the results for the detectability of the O2 and O3 molecular
species in the atmosphere of an Earth-like planet using reflected light at the
visible wavelengths. By quantifying the detectability as a function of
signal-to-noise ration (SNR), we can constrain the best methods to detect these
biosignatures with nest-generation telescopes designed for high-contrast
coronagraph. Using 25 bandpasses between 0.515 and 1 micron, and a
pre-constructed grid of geometric albedo spectra, we examined the spectral
sensitivity needed to detect these species for a range of molecular abundances.
We first replicate a modern-Earth twin atmosphere to study the detectability of
current O2 and O3 levels, and then expand to a wider range of literature-driven
abundances for each molecule. We constrain the optimal 20%, 30%, and 40%
bandpasses based on the effective SNR of the data, and define the requirements
for the possibility of simultaneous molecular detection. We present our
findings of O2 and O3 detectability as functions of SNR, wavelength, and
abundance, and discuss how to use these results for optimizing future
instrument designs. We find that O2 is detectable between 0.64 and 0.83 micron
with moderate-SNR data for abundances near that of modern-Earth and greater,
but undetectable for lower abundances consistent with a Proterozoic Earth. O3
is detectable only at very high SNR data in the case of modern-Earth
abundances, however it is detectable at low-SNR data for higher O3 abundances
that can occur from efficient abiotic O3 production mechanisms.Comment: 16 pages, 10 figures, accepted for publication in the Astronomical
Journa
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