A ten-paddock short duration grazing cell was stocked with yearling heifers at a stocking rate of 0.7 ha per animal unit month and a stocking density of 0.14 ha per animal unit. A continuously-season- long-grazed (CSLG) pasture was used as a control. It was stocked at the same stocking rate, but at a stocking density of 1.4 ha per animal unit. Grazing periods in SDG paddocks were two or three days. Dietary quality was assessed by crude protein · content and in vitro digestibility of esophageal fistula estrusa samples. Three variables of ingestive behavior were measured, including ingestion rate, biting rate, and grazing time. Daily forage in take was estimated by multiplying ingestion rate by grazing time. Animals in CSLG gained significantly more weight in 1983, no statistical differences were detected in 1984, and, in 1985, animals gained more in SDG. No differences were detected in diet quality between SDG and CSLG throughout the study. No treatment differences were de tee ted in ingestive behavior variables in 1984, but ingestion rate was significatantly higher and grazing time significantly less in SDG during 1985. Differences in diet quality and ingestive behavior be tween SDG and CSLG at the beginning and end of the grazing season were evaluated for indications of possibly extending the season of nutritious forage. Such differences were few and inconsistent. Daily changes in diet quality and ingestive behavior during the grazing period within SDG paddocks were large. Diet quality declined significantly during the grazing period in all three years. Ingestive behavioral responses changed significantly, including declines in ingestion rate and increases in grazing time. Forage in take declined during the grazing period on a particular paddock. A model was developed that related behavioral responses to sward characteristics. Ingestion rate and grazing time were predicted from available biomass and herbage crude protein content. The model indicated that declines in biomass and herbage crude protein content translate into rapid declines in ingestion rate, and thus, forage in take. Based on the system studied, grazing periods in SDG paddocks should be two days or less to maintain high levels of livestock performance.

A series of experiments were conducted with pigeons to investigate the variables responsible for differential postreinforcement pause (PRP) durations found on ratio schedules. In Experiment I, behavior on fixed-ratio (FR) and variable-ratio (VR) schedules were compared to behavior evoked by two interpolated schedules. The addition of a single FR 1 component to the FR 50 baseline schedule reduced the overall PRP to a duration comparable to that found on the VR 50 schedule. The addition of both an FR 1 and an FR 215 component to an FR 50 baseline reduced PRP and IRT durations below those on a VR 50 schedule. Experiments II and III were designed to isolate the conditions under which the smallest ratio component exerts predominant control over PRP duration. The results of Experiment II demonstrated that a local increase in reinforcement density was a necessary, but not sufficient condition for reducing median PRP duration. That is, exposure to a response-independnt increase in reinforcement density attenuated, but did not eliminate the reduction in median PRP duration associated with the interpolated FR 1 component. The results of Experiment III demonstrated that neither random session location of the FR 1 component nor unsignaled presentation of the FR 1 component were necessary conditions for reducing the duration of the PRP. That is, a brief, response-dependent increase in reinforcement density was a sufficient condition for reducing PRP duration given a subject free from historical exposure to response-independent reinforcement. It was concluded that the difference in PRP duration produced by two, comparably-sized, fixed- and variable-ratio schedules is a function of the size of the smallest ratio component present in the reinforcement schedule. More generally, the highest local density of reinforcement controls the overall duration of the PRP on a response-dependent, ratio schedule.

No description available.

A key element in moving highway construction projects forward is the ability to acquire the Right of Way (ROW) in a timely manner. Delay in the acquisition process due to multitude of causes will usually lead to major construction phase delays. Identifying the delay factors allows for better time management of the process. A detailed review of the acquisition process at the Mississippi Department of Transportation (MDOT) is used as an example. Reviews of the process in neighboring states are also presented in order to determine other current practices and their likely impact on the acquisition duration. Descriptive and multivariable regression analysis of 35 randomly selected highway projects identified three variables “condemnation”, “number of parcels” and “revisions of plans” for the increase of acquisition duration. Using recognized software with analysis of variance stepwise regression a prediction model is developed and tested for the prediction of acquisition duration. These findings with new processes (forms) and an enhanced flow chart using current information technology procedures are introduced to reduce condemnation cases and to enhance the acquisition process.

Key aspects of prosody have been studied in adults for a number of years; however, less attention has been paid to the acoustic patterns of prosody in children. Thus, the purpose of the present study was to evaluate how a group of 20 pre-adolescent children use prosody to mark contrastive stress compared to a control group of adult speakers. It was of interest to investigate whether the children's use of prosody differed between boys and girls or the part of speech being emphasized. The prosodic patterns of contrastive stress were evaluated in terms of duration, fundamental frequency, and intensity change relative to a baseline production of the same sentence. In addition, a perceptual experiment was conducted to determine if listeners could reliably identify the gender of the child speakers when listening to sentence length utterances. Statistical analysis indicated that there were some differences in the duration and fundamental frequency change as a function of speaker age and the part of speech being emphasized, with relatively minor differences between genders. However it remains unclear if the acoustic differences found in this study were substantial enough to cause a salient perceptual difference. Although previous studies have identified increases in frequency, intensity, and duration as cues of contrastive stress, the present findings revealed patterns that did not consistently conform to these expectations. Limitations in the task design, individual speaker characteristics, and also the type of acoustic measure used may have contributed to these results.

Yes

No description available.

No description available.

No description available.

No description available.