Situational stressors

Transient insomnia lasts less than 3 d and usually is caused by a brief environmental or situational stressor. It may respond to attention to sleep hygiene rules. If hypnotics are prescribed, they should be used at the lowest dose and for only 2 to 3 nights. 

Most of the research on the effects of these stressors on human performance has been done on simple laboratory tasks rather than actual work situations. As a result, the extent that such findings can carry over to tasks in the CPI is debatable. In addition, most of these studies have examined the effect of a single stressor (e.g., noise or heat) only, rather than the combined effect. Nevertheless, some useful guidelines about optimal levels of these stressors are available in the ergonomics literature (e.g., McCormick and Sanders, 1983 Salvendy, 1987). 

The extent to which a particular combination of such "operating environment" factors will be perceived by the workers as being stressful will depend on the available resources such as the quality of the control panel, procedures, training, organizational and social factors, and, finally, the individual characteristics of the workers. The outcome of this transaction between stress factors and coping resources will influence the onset of worker stress. Situations are not stressful merely because of the presence of a number of external stressors, but because they are perceived as such by workers. 

Disadvantages may arise because the behavior observed may not be fully realistic. A static simulation, for instance, may not reveal the true nature of operators dynamic interaction with the system. There is also the possible disadvantage of behavior in a simulator not fully replicating that found in the real situation. This can happen because of the absence of real stressors found in the actual task, for example, risk to life, criticality of the process, and presence of other workers and supervisors. 

The methodology for conducting aquatic model ecosystem studies was well established by the late 1990s. However, the use of the data in risk assessments raised a number of uncertainties regarding their interpretation and implementation [32]. Four of the uncertainties that were identified were the extent to which aquatic model ecosystem data generated in one location could be applied to another situation, the potential influence of mixtures of chemicals or stressors, whether the timing (season) of application would influence the outcome of the study, and whether differences in ecosystem properties (e.g., trophic status) might influence the results. 

Family involvement can be quite helpful in the relapse prevention effort. One potentially useful strategy is for families to make efforts to reduce relationship stressors. These efforts will likely require couples or family therapy, which ideally will improve communication within the family system and potentially reduce friction. In addition, family members may learn to reduce any negatively expressed emotions toward the client. Family and couples therapy would be highly recommended if those stressors represent a high-risk situation for the client in question and if the family members or partner are supportive of the client s efforts toward recovery. 

Significant psychosocial stressors that are not addressed and ameliorated are frequently assumed to contribute to persistent depressive symptomatology despite adequate pharmacologic intervention. In such situations, supportive, interpersonal, and cognitive therapy may be necessary adjuncts to medication. 

SSD-based approaches are used for monitoring and trends analyses regarding toxic mixtures per se, and for the analysis of situations of multiple stressors. However, none of the SSD-based methods assumes a priori that only concentration addition or response addition would apply. Even the earliest applications recognize the relevance of both models. These uses of SSDs are described under Tier-3 methods. 

In obtaining the clinical history, particular attention should be paid to situations that may provoke episodic symptoms. Skipping meals, mild viral illnesses, and exercise are examples of metabolic stressors that may result in symptomatic decompensation. Importantly, results of... 

Transient situational insomnia—sleep difficulty that is acute in onset and directly related to a stressor. 

Psychophysiological insomnia—may have started with transient situational insomnia hut persisted after the stressor was resolved. 

Health professionals often experience burnout within two years of beginning their jobs (Muldary, 1983). Moreover, it is frequently the neophyte professional, as opposed to the more experienced professional, who burns out during the first two years. Multiple stressors commonly experienced as part of the professional socialization process can, if left xmchecked, contribute to burnout. All too often, there are discrepancies between what students learn in the somewhat idealistic environments of professional training programs and the day-to-day realities of the working world. Moreover, neophyte professionals are likely to feel stress as they encoxmter new situations or those for which they have not received specific training. New professionals quickly realize how much they do not know and how much they still need to learn. 

Under resting conditions, CRH and AVP are released from the hypothalamus in a pulsatile fashion with a frequency of 2-3 episodes per hour (Engler et al., 1989). The amplitude of the neuropeptide pulses normally increases in the morning, resulting in a circadian fluctuation in ACTH and cortisol levels. This daily rhythm is modulated by feeding and activity schedules, but is particularly perturbed by stressful stimuli originating internally (e.g., anxiety or systemic infection) or externally (e.g., threatening situations). Thus, acute stressors lead to activation of the stress response. 

Toxicity data from several sources is usually compiled and compared. Generally, there are acute and chronic data for the stressor on one or several species. Toxicity data are usually limited to species and the species of interest, as an assessment endpoint may not have appropriate data available. This situation often occurs with threatened or endangered species since even a small-scale toxicity test involves relatively large numbers of animals to acquire data of sufficient quality. 

Test the hypotheses listed in Step 8. Hypothesis can be tested using a variety of field, mesocosm, or laboratory test methods. In an ideal situation it should be possible to make predictions based upon known concentrations and then sample that field site in order to confirm effect or no-effect. It may be necessary to rework the risk assessment in order to reduce uncertainty, or a stressor-habitat-effect linkage may be incorrect. Testing the risk predictions allows feedback into the assessment process improving future predictions. 

Many factors can influence the utility of available ecological effects data for problem formulation. For example, the applicability of laboratory-based tests may be affected by any extrapolations required to specific field situations, while the interpretation of field observations may be influenced by factors such as natural variability or the possible presence of stressors other than the ones that are the primary focus of the risk assessment... 

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