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Yes / Life in a seasonally variable environment has evolved to interpret the time of year through day length (photoperiod) which is translated into a neurochemical signal. In mammals, the pars tuberalis is a key site where seasonal time signal (melatonin) interfaces and relays photoperiodic information to the hypothalamus via thyrotropin. Recent work has elucidated a potential circannual clock in ‘calendar cells’ of the pars tuberalis. In the hypothalamus, tanycytes are an integral part of the hypothalamic network. Previous studies show the importance of local synthesis of thyroid hormone and retinoic acid in tanycytes. Recently novel downstream neuroendocrine signals, e.g. VGF, FGF21 and chemerin, were identified to govern seasonally appropriate phenotype. Additionally, the hypothalamic-pituitary-growth axis has been implicated in seasonally bodyweight and torpor regulation. Here, we will focus on the endocrine drivers of photoperiod response and highlight novel downstream effects on bodyweight and growth focusing on recent findings from seasonal rodent studies.

Apple preharvest fruit drop frequently results in severe economic losses. Cultural control of preharvest drop has relied upon plant growth regulators (PGRs), but the loss of daminozide (Alar) and 2,4,5-TP has severely limited the choices of effective stop-drop compounds. A more complete understanding of factors involved in preharvest drop is therefore imperative. Experiments were conducted to provide information about cellulase activity in the abscission zone, effects of applied auxin and ethylene biosynthesis inhibition on drop, changing sensitivity to abscission induction during the season, and relationships among seed number, fruit weight, and day of drop. Observational studies were used to study effects of fruit maturity, canopy positions, and morphology of stem attachment on time of fruit drop as well as characterizing the natural timing of late-season fruit drop. Increased activity of cellulase, but not polygalacturonase, in the abscission zone was detected within 4 days of cutting fruit to induce abscission. Both aminoethoxyvinyl glycine (AVG) and naphthaleneacetic acid (NAA) applied 2 or 4 days after cutting delayed drop, but NAA delayed drop 1.6 days longer than did AVG. Fruit of "RedChief Delicious"(D) exhibited a significantly reduced sensitivity to abscission-inducing treatments from mid-June until early July compared to earlier orr later in the season. Application of plant growth regulators to cut fruit revealed a significant interaction of NAA treatment with AVG treatment such that NAA delayed drop when applied with AVG but not without AVG. Fallen fruit had lower starch and higher soluble solids than fruit on the tree on the day of collection. The highest fruit in the canopy fell an average of 4.4d earlier than the lowest fruit. Day of drop was not different for fruit from king blooms vs. side blooms within an inflorescence. There was a trend for fruit from first year wood to drop later than fruit from older wood on "Delicious", but not "Smoothee Golden Delicious" trees. There was no detectable effect of angle of orientation of the subtending spur on the limb, the pedicel:spur abscission zone, or fruit axis of symmetry on time of fruit drop. No difference was detected in time of fruit drop between East and West or North and South sides of the trees. No substantial variation in day of drop of individual fruit was explained by number of seed in the fruit. Daily drop was recorded for three cultivars ("RedChief Delicious", "Smoothee Golden Delicious", and "Commander York") for three years. Variance of average day of drop from year to year was 40.1, while variance among cultivars within a year was 51.8. Variance from tree to tree within each cultivar, within each year, was only 18.6. Multiple regression modeling to identify relationships between weather factors and daily fruit drop revealed that much of the variability in time of drop was due to factors other than the weather events modeled. The best regression models developed explained only 8% to 35% of the variability in time of drop. The most important weather factors were daily minimum temperatures and precipitation. Rain events of greater than 5.0 mm following a drier period appeared to cause increased drop of all three cultivars in one out of the three years investigated. / Ph. D.

Dissertation (Ph.D.) - Simon Fraser University, 2005. / Dissertation (Dept. of Psychology) / Simon Fraser University. Includes bibliographical references (leaves 86-93).

The seasonal influenza (flu) vaccine has been shown to prevent flu outbreaks that can cause debilitating effects on the body and even death. Underserved members of Black communities are more likely to refuse the flu vaccine than are persons of other ethnicities. The purpose of the project was to determine from a needs assessment the reasons for flu vaccine refusal in the Black population of an inner city clinic in order to develop tailored communication and nursing actions that promote awareness of the flu vaccine's importance and safety. The health belief model constructs (perceived susceptibility, perceived severity, perceived benefits, and perceived barriers) were used to guide the project. A survey based on the constructs of the health belief model was administered to a convenience sample of 40 adult patients in an inner city clinic who completed the anonymous survey while they waited for the physician. Descriptive statistics showed that adults ages 18 to 36, who were the largest group of respondents (n = 33), agreed to be vaccinated and believed the flu to be a serious disease for their age group. Reported barriers to vaccination included finding time to get vaccinated and the belief that the vaccine causes the flu. The findings supported development of an annual seasonal flu vaccine campaign that included verbal and written education, informational posters, social media messages, and a standing order to offer and administer the injection to all adults served by the practice. Social change implications are expected to include decreased morbidity and mortality from flu among the Black inner city patients and closer alignment of the clinic with the Healthy People 2020 vaccination goals.

Temperatures selected seasonally by adult mountain whitefish were measured in the laboratory in a horizontal gradient. Final preferendum estimates, based on acute (3-hour) preference tests conducted with fish acclimated to 5, 10, and 15 C each season, were 17.7 C (pre-spawning), 11.9 C (post-spawning), 9.9 C (winter), and 16.3 C (spring). Seasonal influence on temperature selection was evident on the basis of differences in final preferenda, covariance analysis of responses of laboratory-acclimated fish, and temperature selection by fish held at ambient river temperatures. Post-spawning and winter groups selected lower temperatures than did pre-spawning and spring groups. Pre-spawnine fish selected temperatures unsuitable for embryo survival. Reproductive status as reflected by gonad size was evidently not a factor that influenced seasonal temperature selection of adult whitefish.

We introduce the Seasonal Beliefs Questionnaire (SBQ), a self-report inventory of maladaptive thoughts about the seasons, light availability, and weather conditions, proposed to constitute a unique cognitive vulnerability to winter seasonal affective disorder (SAD; Rohan, Roecklein, & Haaga, 2009). Potential items were derived from a qualitative analysis of self-reported thoughts during SAD-tailored cognitive-behavioral therapy (CBT-SAD) and subsequently refined based on qualitative feedback from 48 SAD patients. In the psychometric study (N = 536 college students), exploratory and confirmatory factor analyses pruned the items to a 26-item scale with a 5-factor solution, demonstrating good internal consistency, convergent and divergent validity, and 2-week test-retest reliability. In a known groups comparison, the SBQ discriminated SAD patients (n = 86) from both nonseasonal major depressive disorder (MDD) patients (n = 30) and healthy controls (n = 110), whereas a generic measure of depressogenic cognitive vulnerability (the Dysfunctional Attitudes Scale [DAS]) discriminated MDD patients from the other groups. In a randomized clinical trial comparing CBT-SAD with light therapy (N = 177), SBQ scores improved at twice the rate in CBT-SAD than in light therapy. Greater change in SBQ scores during CBT-SAD, but not during light therapy, was associated with a lower risk of depression recurrence 2 winters later. In contrast, DAS scores improved comparably during CBT-SAD and light therapy, and DAS change was unrelated to recurrence following either treatment. These results support using the SBQ as a brief assessment tool for a SAD-specific cognitive vulnerability and as a treatment target in CBT-SAD. (PsycINFO Database Record (c) 2019 APA, all rights reserved).