Tracking the sources of Leptospira and nutrient flows in two urban watersheds of Puerto Rico.

This study investigated the relationship between nutrient levels, source of fecal contamination, and pathogenic Leptospira in Puerto Rico's northern coast and San Juan Bay Estuary (SJBE) aquatic ecosystems. Microbial source tracking (MST) was also used to investigate the connections between sources of feces contamination and the presence of Leptospira. Eighty-seven water samples were collected during the June (n=44) and August (n=43) in 2020. To quantify phosphorus and nitrogen concentrations, standard USEPA protocols were utilized, specifically Methods 365.4 for total and dissolved phosphorus, 351.2 for total Kjeldahl nitrogen and ammonium, and 353.2 for nitrate. Lipl32 gene-specific quantitative polymerase chain reaction (qPCR) was used to detect the presence of Leptospira. Human (HF183), canine (BacCan-UCD), and equine (HoF597) MST assays were utilized to trace the origins of fecal contamination. Forty one percent of the locations exceeded Puerto Rico's authorized total phosphorus limit of 160 g L-1, while 34% exceeded the total nitrogen limit of 1700 g L-1. Nearly half of the streams examined are affected by eutrophication. The MST analysis identified human and canine feces as the most prevalent contaminants, affecting approximately 50% of the sites. In addition, Leptospira was detected in 32% of the June samples. There was a significant correlation (r = 0.79) between the incidence of pathogenic Leptospira and the human bacterial marker (HF183). This study illuminates the central role of anthropogenic inputs in nutrient enrichment and pathogen proliferation in Puerto Rico's aquatic ecosystems.

Marine vessel control using the tiller-motor system.

Operator performance on the tiller-motor system was investigated in a field survey and in a tracking simulator. Boat operators in Study 1 reported both control difficulties and discomfort, when using their tiller-motor system. Participants in Study 2 operated a tiller-motor simulator of a boat navigating a river over a 20 min period. Directional and speed control performance was found to be poor, particularly on the first trials and under emergency conditions. These results support the suggestion that the incompatible nature of the control/response relationship in tiller-motor systems can cause operator difficulties. The dimensions of the simulator were systematically varied and found to influence operator shoulder extension, and ratings of exertion and discomfort. Recommendations for tiller-motor system design and installation are offered.

Prompting correct lifting posture using signs.

The use of a symbol to prompt the adoption of correct lifting posture was examined in three studies. Study 1 used an Appropriateness Test to evaluate nine symbols designed to encourage the adoption of correct lifting posture. Four symbols met the appropriateness criteria and were tested for comprehension in Study 2. Study 3 examined the effect of the best performing symbol from Study 2 in a field setting which involved subjects lifting a small box. Results indicate significant increases in the adoption of the use of correct lifting posture when the symbol was present compared to a control condition. The study also identified the placement of a lifting criterion symbol onto packaging as a useful technique for communicating safety information.

Taking breaks from work: an exploratory inquiry.

Two studies concerned with taking breaks from either mental or physical work are presented. In the first study, a questionnaire was given to 101 students in which they answered questions about their own break taking and that of others. They also completed a time management questionnaire and scales about procrastination, self-esteem, and work overload. In the second study, 17 students kept detailed diaries of their daily break-taking behavior over a 6-week period. Results are discussed in terms of the types of reasons given for taking breaks and the possible discrepancies between such reasons and the actual activities engaged in during breaks.

Reconstruction of the duration of autobiographical events.

In two experiments, subjects estimated autobiographical event duration. Ornstein's (1969) storage-size model of duration estimation was tested in Experiment 1 by using 187 autobiographical events with an actual duration range of 3-550 days. Subjects' diaries were used to obtain information about these events, which occurred up to 20 years before the study. Contrary to the predictions of Ornstein's model, estimated duration was not proportional to event knowledge, nor was any evidence of a time-order error effect or the filled-duration illusion found. Estimated duration was reasonably accurate, even when the event could not be remembered, suggesting that subjects may have reconstructed event duration. Evidence consistent with duration reconstruction through the use of general event knowledge was found in Experiment 2: Subjects provided with general descriptions of the events used in Experiment 1 gave estimates similar to those obtained in Experiment 1 for specific events.

Categorisation of action speed and estimated event duration.

Two experiments investigated the relationship between the words used to describe event actions and estimates of event duration, and whether this relationship might account for some of the variation found in duration estimates. Experiment 1 manipulated sets of action words within an account of a robbery, and replicated the Burt and Popple (1996, Experiment 1) finding that estimated duration decreased as the implied action speed of the robbery increased. Experiment 2 found considerable variation across individuals in the action words they used to describe a robbery, and that the number of action words used was negatively correlated with estimated duration. Taken together the experiments suggest that the interaction between individual differences in action categorisation and the use of inferences about the relationship between action speed and event duration, may account for some of the between-subject variation found in estimates of event duration.

Retrospective duration estimation of public events.

In three experiments, we investigated subjects' retrospective estimation of the duration of publicly reported events such as, for example, the Falkland's war. In Experiment 1, duration estimates were found to be positively correlated with event knowledge, in keeping with Ornstein's (1969) model of duration estimation. Event duration was, however, generally underestimated, suggesting that the relationship between event knowledge and estimated duration might reflect an increase in estimation accuracy. Other results of Experiment 1 were consistent with this interpretation and suggested that the duration estimates might be largely reconstructed. In Experiment 2, duration estimates of specific events and general categories of events were found to be highly correlated, and the subjects in Experiment 3 indicated that they used knowledge of the general characteristic of different types of events to estimate event duration. Overall, reallife duration estimates appear to be based on a combination of specific event information and knowledge derived about that category of event.

The force of events: cross-modality matching the recency of news events.

Subjects recorded their impressions of the recency of news events by squeezing a dynamometer. This measure of recency was significantly related to the vividness of the memory for the event, when actual date was controlled for, and the relationship was stronger than that obtained when subjects wrote down their estimates of the dates. The results support the existence of distance-based processes such as inference from trace strength in our memory for when events occurred.

What happens if you retest autobiographical memory 10 years on?

Burt (1992a, 1992b) reported data on the autobiographical memory of diarists for events that had occurred on average 3.3 years earlier. This paper reports data on 11 of the diarists, who were recontacted after a further 10 years and who agreed to a retest of their memory. Estimates of event date and event duration from the two recall attempts were compared. As predicted, duration estimation was extremely stable and showed no detrimental effects of the additional 10 years of retention interval. Estimation of event date was predicted to show an increase in forward telescoping due to the increased remoteness of the event sample, but, contrary to this prediction, backward telescoping dominated dating errors. A combination of the establishment of a recent boundary and Kemp's (1999) associative model of dating is proposed as an explanation for these results. It is argued that the nature of dating errors may depend on the time of the event's occurrence in the life span and the age of the individual dating the events.

Ordering autobiographical experiences.

This study examined individuals' memory for the temporal order of autobiographical events and for the components that constitute autobiographical events. Study 1 measured performance on an across-event ordering task that involved the chronological arrangement of cards that displayed event labels. Results indicated poor ordering ability across events, but a reasonable ability to order clusters of events. Study 2 compared within-event and across-event ordering using computer-presented digital photographs. Participants were better at ordering the photographs in their own across-event trials than in their within-event trials. The results are discussed in terms of the retrieval of temporal information under within- and across-event conditions.