Showing papers by "University of Maryland, Baltimore County published in 1976"

Duration of the effect of good mood on helping: "Footprints on the sands of time."

Abstract: Two field studies investigated the time course of the effect of feeling good on helping. Subjects were given small packets of stationery by a confederate who went from door to door. Then, at different intervals, each subject received a \"wrong number\" telephone call during which he or she had the opportunity to help. Results showed that subjects who had received stationery helped more than did those in either of two control groups. The effect declined gradually over time, and by 20 minutes after receipt of the stationery, the experimental group did not differ from the control groups. The time course of the decline in helpfulness and the basic relationship between good mood and helping were discussed in terms of cognitive processes.

Lactic acid-sensitive receptors on the antennae of the mosquito,Aedes aegypti

Abstract: 1. A pair of chemoreceptor neurons sensitive to lactic acid (LA) was identified in the grooved-peg (A3) sensilla on the antennae of the mosquito,Aedes aegypti. 2. One chemoreceptor responded to LA with an increase in spike frequency, whereas the other chemoreceptor exhibited a decrease in spike frequency when presented with LA. 3. CO2, either alone or in combination with LA, elicited no change in spike frequency of either LA-sensitive neuron, indicating that the behavioral synergism of CO2 and LA occurs centrally and not at the primary receptor level. 4. Water vapor induced such a weak excitatory response in both LA-sensitive neurons that their involvement in the detection of water vapor is questioned. 5. The insect repellent, DEET, inhibited both LA-sensitive neurons. DEET plus LA was additive in the LA-inhibited cell, whereas the LA response of the LA-excited cell was attenuated by DEET. 6. The reaction spectra of the LA-sensitive neurons were determined using pure compounds (Table 1). 7. The importance of LA in the host-finding behavior of the mosquito is discussed.

Protein transport: A selective membrane mechanism

Abstract: Proteins are selectively sequestered by a number of cell types. However, only in oocytes is the process sufficiently aggravated and specific to be readily studied. In these cells certain serum proteins are taken up in proportions different from those found in the serum. In vitro incubations of hormonally stimulated and synchronous mosquito oocytes show that the only protein capable of initiating the transport process is the female specific yolk protein. Heterologous proteins such as IgG, bovine serum albumin, cytochrome C, and ferritin are inactive. The female specific protein is a phosphoglycolipoprotein. It is synthesized in the fat body, a liver analog in the insect, and passed into the serum before being transported into the oocytes. Preliminary kinetic analysis shows the uptake process to be specific with an apparent Km of about 10(-7) M. Glycolytic inhibitors stop protein uptake. The receptor-mediated binding steps in the transport process are most easily studied in the chicken because of the enormous amount of oocyte membrane available from a given oocyte and because up to 1 gm of protein is normally transported per day per oocyte. IgG and the hen specific phosvitin lipovitellin are two of the physiologically important proteins that are transported intact into the chicken oocytes. The uptake appears selective as shown by studies with iodinated proteins. Ferritin conjugated to IgG is shown by electron microscopy to bind to isolated plasma membranes only where coated pits have formed, whereas ferritin alone is not seen localized on any membrane surface. These very specialized regions of the membrane are similar to micropinocytotic pits but, in addition, possess on their cytoplasmic side dense ridges that form the coat. Transport involves binding to the coated pits, the pinching off of the pits, and the subsequent movement of the coated vesicles in the cytoplasm.

Relative abundances of living and dead molluscs in two Californian lagoons

Abstract: Assemblages of living benthic invertebrates (predominantly bivalve molluscs) from the sand-channel habitat of two Southern California (U.S.A.) lagoons were sampled on ten occasions over a 37-month period. A one-time sampling of the corresponding assemblages of accumulating dead remains made possible a contrast of living and dead assemblages designed to assess the biasing effects of post-mortem transportation, shell dissolution, and time-averaging. Species-by-species comparisons of the living and dead molluscs found together in the same samples strongly suggested that post-mortem transportation is insignificant within this high-energy habitat. A similar conclusion arose from contrasting the pattern of spatial heterogeneity of the living community with that of the dead assemblage. Species presence-and-absence comparisons were generally more reliable than comparisons of relative abundances. Adjustments for experimentally determined rates of post-mortem shell dissolution proved significant and further decreased the correspondence in relative abundances between living and dead assemblages. Greater temporal variability of living populations at Mugu Lagoon, probably caused by a more harsh physical environment, increased the differences in composition between living and dead assemblages, which suggests that correspondence in relative abundances between living and dead assemblages generally should be expected to decrease as the life environment becomes more harsh.

The turtle technique: An extended case study of self-control in the classroom

Abstract: A preliminary investigation of the Turtle Technique, a procedure for helping emotionally disturbed children control their own impulsive behavior, is described. The technique consists of four components: the “turtle response,” relaxation, problem-solving, and peer support. Eleven children drawn from two classrooms were instructed in the use of the Turtle Technique for the self-control of aggression. The procedure was introduced according to a multiple-baseline design. Results revealed significant decrements in aggressive behavior in both classrooms. Implications for further research were considered.

Mathematical tools for applied multivariate analysis

Abstract: This book introduces matrix algebra to students in behavioral and administrative sciences. It clearly defines the relevance of the exercises to concerns within the business community and the social and behavioral sciences. Readers will gain a technical background for tackling applications-oriented multivariate texts.

Lump detection in simulated human breasts

Abstract: Sixteen observers palpated silicone models of human breasts containing lumps 1.6-12.1 mm in diameter. Detectability depended on the size of the lump, producing a systematic psychometric function. In eight observers who participated in three or more sessions, performance improved with practice, with most improvement occurring within one or two 26-trial sessions. Three-week retention measures disclosed no appreciable decrease in performance, but a significant correlation was found between the number of lumps detected and duration of trial (p < .01). There was no difference in performance between four observers who used their preferred hands and four observers who used their nonpreferred hands. These data establish that examination of breast models for the detection of lumps simulating cancer is a task amenable to experimental analysis.

Floral activity in solutions of deoxyribonucleic Acid extracted from tobacco stems.

Abstract: For Nicotiana tabacum cv. Wis. 38 plants, the capabilities of solutions containing DNA, extracted from either homogenates of stems in a floral state or nuclei of stems in a vegetative state, to effect flowering of vegetative plants have been studied. Previous work indicates that the DNA from homogenates of stems in a floral state is mainly nuclear. If DNA solutions are supplied to axillary buds of vegetative plants and if the axillary buds are defoliated every 4th day for 12 days, the buds supplied a solution of DNA from stems in a floral state initiate flowers under noninductive conditions, and the buds supplied a solution of DNA from stems in a vegetative state remain vegetative. Heating and rapidly cooling a solution of DNA from stems in a floral state enhances its floral activity. Heating and cooling a DNA solution also results in novel flowers showing up in many treated plants. Novel flowers are more striking in the offspring than in the parents. The capabilities of heated-cooled DNA solution to initiate flowers in noninductive conditions and to cause novel flowers are eliminated completely by treating (before heating and cooling) the DNA solution with deoxyribonuclease. Heated-cooled solutions of DNA extracted from nuclei of either vegetative stems or vegetative leaves contain no floral activity.

A motivational environment for behaviorally deviant junior high school students

Abstract: A contingency management program was established in a junior high school to better manage and educate students having histories of severe misconduct. School administrators selected 46 eighth-graders having multiple suspensions for misbehavior. Students (N=32) in two of the schools remained in traditional programs, serving as controls, whereas students (N=14) in the third school participated in a token reinforcement program. Reinforcers provided in the afternoon were contingent upon achievement and discipline during morning academic periods. Home-based reinforcers were established to support school behavior. Compared with the control group, significant reductions in negative school behavior as well as greater increases in academic achievement were obtained for the treatment group, thus supporting the efficacy of contingency management for adolescent school misbehavior.

Binding to specific receptors on oocyte plasma membranes by serum phosvitin-lipovitellin.

Abstract: Specific binding sites for the serum complex of phosvitin and lipovitellin have been shown to exist on the outer surface of rapidly growing chicken oocytes. The existence and specificity of these sites were demonstrated by competition for binding to unfixed oocyte membrane fragments and by displacement of already bound and labeled phosvitin-lipovitellin from formaldehyde-fixed membranes. Only unlabeled phosvitin-lipovitellin competed with the 125I-labeled complex for binding to the fragments of displacement of bound label; IgG isolated from egg yolks and bovine serum albumin were ineffective.

Predicting recognition during storage: The capacity of the memory system to evaluate itself

Abstract: The major goal of this experiment was to determine the accuracy with which subjects could predict at input their later recognition performance. Predictions were based on words varying on a number of attributes. Four categories of words were used: nonsense, abstract, concrete, and emotional. The number of words correctly recognized increased in the foregoing order although the difference between the concrete and emotional words was marginal. When all words were combined, there was a strong relationship between predicted recognition and actual recognition for words that were hits with a "very sure" confidence rating. Additionally, subjects considerably underestimated their later recognition performance. The results indicated that a new interpretation of the mechanism underlying "correct rejects" is feasible. The relevance of the results to other memory issues was also discussed. Despite the voluminous literature on verbal learning and memory, much remains to be learned about what would seem to be a core issue: What happens in terms of cognitive variables when a person sees or hears a word? A greater appreciation of this deceptively simple state­ ment is obtained if a few possibilities are outlined. Words are not stored solely on the basis of their phono­ logical characteristics, rather a storage complex in the sense of several attributes (Bower, 1967 ; Morton, 1970 ; Norman & Rumelhart, 1970 ; Underwood, 1969 , 1972; Wickens, 1970 , 1972) or propositions (Anderson & Bower, 1973) seems to be a more appropriate descrip­ tion . But is this complex automatically activated given a specific context or does conscious control playa role (Posner & Warren, 1974)? Consider another problem. How can a person accurately predict that he knows a word, in the absence of recall of that word-the "tip of the tongue" phenomena (Brown & McNeill, 1966)? The ramification of these questions about memory structure in relation to recognition memory was the focus of the present investigation. More specifically , consider the remarkable ability of subjects to correct­ ly reject words not previously presented. When subjects place a high degree of confidence in their decisions, they are correct about 800/0-90% of the time, the exact per­ centage depending on the usual variables affecting recog­ nition memory. The traditional method of accounting for correct rejects as well as hits is to use a familiarity dimension , the subject reporting that he is sure that a word is " old" if it is very familiar (within the context

Regulation of RuDP carboxylase/oxygenase activity and its relationship to plant photorespiration

Abstract: RIBULOSE 1,5-diphosphate carboxylase/oxygenase (fraction 1 protein), the most abundant protein in nature, is a key photosynthetic enzyme catalysing the addition of CO2 to ribulose 1,5-diphosphate (RuDP) to form two molecules of phosphoglyceric acid (PGA). The enzyme also has a competitive oxygenase function catalysing the splitting of RuDP by O2 to form one molecule of PGA and one molecule of phosphoglycolate1–3. The latter function of this enzyme has been suggested to be the primary source of phosphogly-colate, the principal substrate for photorespiration5.

Exponential Fourier densities on SO(3) and optimal estimation and detection for rotational processes

Abstract: In this paper, we will present a new representation of a probability density function on the three dimensional rotation group, SO(3), which generalizes the exponential Fourier densities on the circle. As in the circle case, this class of densities on SO(3) is also closed under the operation of taking conditional distributions. Several simple multistage estimation and detection models will be considered in this paper. The closure property enables us to determine the sequential conditional densities by recursively updating a finite and fixed number of coefficients. It also enables us to express the likelihood ratio for signal detection explicitly in terms of the conditional densities.

Regulation of translation in rabbit reticulocytes and mouse L-cells; comparison of the effects of temperature.

Abstract: Various parameters of protein synthesis were analyzed in rabbit reticulocytes exposed to various temperatures for up to five hours. Between 10 degrees C and 40 degrees C total protein synthesis exhibited two different apparent activation energies (36 kcal/mole, 10-24 degrees C; 22 kcal/mole, 24-40 degrees C), as did protein elongation and release (35 kcal/mole, 10-25 degrees C; 12 kcal/mole, 25-40 degrees C). However, the level of polysomes remained essentially unchanged between 0 degrees C and 42 degrees C which implies that the activation energy for polypeptide initiation is quite similar to that for elongation and is also biphasic. This situation is different from that in cultured mouse L-cells where the polysome level is dependent on temperatures. Nevertheless, reticulocytes and L-cells appear to be similar in their temperature dependence of initiation and in their rate of elongation (5-6 amino acids/second at 36 degrees C.

Power Sum Distributions: An Easier Approach Using the Wald Distribution

Abstract: Power sum distributions arise in communications noise and highway noise models. Inverse Gaussian or Wald distributions with the same index of dispersion are similar and infinitely divisible, and often closely approximate lognormal distributions, and, thus, are more suitable than lognormals for theoretical studies. The Wald distribution is an exact model for Poisson distributed point sources with Erlang (O) emissions of noise power.

Mother-Infant Interaction and its Study

Abstract: Publisher Summary This chapter discusses the direction of influence in child socialization in general and in caregiver–infant interaction in particular. Theoretical and methodological approaches to caregiver–infant interaction and the directions of influence within that interaction are discussed in the context of two general theoretical perspectives for human development—the organismic and the mechanistic. These disparate models imply very different conceptualizations of behavioral development. The implications of the two models are very similar for the empirical study of the directions of effects within caregiver–infant interaction. The heuristic functions of the two theoretical perspectives would be very dissimilar. Within the organismic approach, research would focus on the (1) descriptive study of the course of development to discover the formal causes of development, which are not open to empirical determination and (2) facilitative and inhibitory effects on the course of development. Mechanistic models have been developed to order sequential relations between environmental and behavioral events. Within such an approach, research would focus on the study of the functional relations among sequences of variables, to provide the description and determinants of development.

Imagery, affective arousal and memory consolidation

Abstract: A DISPARITY exists between the methods and theory that have been developed to study human memory and those used in animal learning studies. Present research strategies in human memory focus on (1) differences in the stimuli-to-be stored in memory (such as the extent to which words can be encoded)1; (2) conditions that precede new learning which influence the acquisition, stimulus transformation and encoding of input; (3) the context in which information is presented at the time of storage or retrieval from memory (where context determines the specific encoding strategy used to store and retrieve information)2; and (4) conditions that affect storage decay (such as those which might prevent rehearsal or precipitate “unlearning” of information stored in memory). The main theme of this research stresse stimulus characteristics, often causally defined, as determinants of input–output relationships in memory. Few attempts have been made to develop the structural detail of human memory with respect to underlying biological mechanisms.

Cruising speed during migration of the striped mullet (mugil cephalus l.): an evolutionary response to predation?

Abstract: A recent elegant theoretical model derives the energetic efficiency of various cruising speeds of migrating fishes (Weihs, 1973b). In schooling species utilizing carangiform and subcarangiform locomotion, a cruising speed of approximately one body length per second is expected to minimize the energy required to migrate a given distance. Although a great deal of information exists on swimming speeds of fish (reviewed by Bainbridge, 1958; Blaxter, 1969), most studies have been concerned with either 1) laboratory tests of maximum burst speeds (e.g., Blaxter and Dickson, 1959), 2) the interdependence of swimming speed and physiology (Blaxter and Dickson, 1959; Radakov, 1964; Brett, 1965) or 3) the functional morphology of locomotion (Breder, 1926; Alexander, 1967; Magnuson, 1970, 1973). Those few laboratory measurements that probably correspond to actual long-distance cruising speeds seem to agree rather well with the predicted energetic optimum (Weihs, 1973b). However, because of obvious procedural difficulties accurate field observations on fish cruising speeds are lacking. Therefore, in this report I compare field measurements of the swimming speeds of migrating striped mullets (Mugil cepholus L.) to the energetic optimum predicted by assuming that natural selection has favored energetic efficiency. The resulting large discrepancy between observed and predicted cruising speeds can be resolved best by assuming 1) that schooling has resulted in significant gains in hydromechanical efficiency and 2) that the selective force of heavy predation on migrating mullets has favored extremely rapid swimming speeds despite the cost of energetic inefficiency. During their annual fall migrations, schools of striped mullets move south along the mid-Atlantic coast of North America. The fish often swim within 3 m of the shore in fall seas that are frequently calm and clear, making direct observation of their swimming speeds feasible. From 15 September-l October 1974, mullets were timed with a stopwatch as they migrated southward over one of four premeasured distances located along virtually straight stretches of shoreline. These measured courses, two in Seaside Park and two in Island Beach State Park (Ocean County, New Jersey, USA), ranged from 18.1 to 45.2 m in length. Ideal weather conditions, including clear ocean waters (underwater visibility> 10 m), calm seas (waves <.3 m) , bright sunshine, and negligible winds, permitted easy viewing of the mullets from high on the beach about 10 m away from the shoreline. Longshore currents were negligible judging by the lack of net movement of siphonophores and other more visible items suspended in the water near shore. After each of 7 \"schools,\" ranging in size from 1 to approximately 100 mullets, was timed over one of the measured courses, the school was then sampled with a \"cast net.\" After the total length of each sampled mullet was measured with calipers, all 27 captured mullets were frozen for future examination. Total length of mullets varied from 11.5 to 16.4 em, with an average of 14.6 cm ± 0.19 (SE). Swimming speed of individual mullets (Table 1) ranged from 4.9 to 9.3 body lengths per second, with an average speed of 7.0 b.l.1 sec ± 0.38 (SE). No significant relationship appears between mullet size and cruising speed in these data because size variation between schools is small relative to size variation within schools. Although measured over a relatively short distance, these speeds probably represent actual cruising speeds, not maximum burst speeds. I have often followed schools of mullets along the beach for long distances (up to 2 km) without observing any apparent change in swimming speed. The presence of a human observer on the beach does not seem to alter their behavior: even when observed from blinds at a great distance (20 m) schools appear to move equally rapidly. Furthermore, striped mullets often demonstrate their capacity for even greater bursts of speed when theatened by the approach of a cast net or when actively pursued through the water. Although the sample size is small, these data have sufficiently low variance to demonstrate that true cruising speeds of M. cephalus during fall migration are surprisingly high when compared to the energetic optimum of one b.l.1sec predicted by Weihs (1973b) and to typical published cruising speeds of 2-3 b.L'sec for other fishes (e.g., Cushing and Harden Jones, 1968;

The measurement of temperature tolerance: Verification of an index

Abstract: A shock-recovery assay for temperature tolerance is demonstrated to predict survival of the copepod Eurytemora affinis at high temperature. The assay can be modified to allow comparison between widely divergent treatment groups.

Meiosis in male Drosophila melanogaster. II. Nonrandom segregation of compound-second chromosomes.

Abstract: The segregation of compound-second chromosomes in males from two different stocks has been examined. Segregation is random in males from the C(2L)RM4, dp; C(2R)RM4, px stock. Gametes containing only one of the two compound chromosomes comprise 50% of the gametes, and gametes containing either both elements or neither element make up the other 50% of the gametes.——In males from the C(2L)RM, b; C(2R)RM, cn stock, gametes containing either C(2L)RM, b or C(2R)RM, cn make up the majority of the gametes. Gametes containing both chromosomes or neither chromosome account for only 2-3% of the gametes. The nonrandom segregation is due to the C(2R)RM, cn chromosome.——Viability is reduced in flies carrying the C(2R)RM, cn chromosome. This includes larval lethality, delayed development and premature adult lethality. Cytologically, this chromosome contains a large duplication of 2L material, which includes material proximal to region 38 or 39. It is suggested that the viability and segregational properties associated with this chromosome are due to the duplicated 2L material.