Strengths use and work-related flow: an experience sampling study on implications for risk taking and attentional behaviors

PurposeUsing positive psychology theories, the authors build a model to test whether episodic fluctuations in strengths use coincide with changes in flow experiences and further predict risk-taking behavior and attentional performance.Design/methodology/approachA field study covering five working days was conducted among 164 Chinese employees; twice a day, they were asked to complete questionnaires regarding their strengths use and flow experiences during the previous hour (N = 938 observations). Immediately afterward, their risk-taking behaviors and attentional performance were tested using computerized tasks.FindingsMultilevel analyses showed that when employees used their strengths more often in the previous hour, they also reported an increase in flow. Episodic fluctuations in flow were positively associated with risk taking and negatively related to attentional performance.Practical implicationsEmployees should be encouraged to use their strengths more at work, as this might increase their flow experiences. At the same time, they should pay attention to the downsides of flow (i.e. less attention after flow) at an episodic level.Originality/valueThe authors add to previous studies by using a more objective approach, namely employing computerized tasks on risk-taking behavior and attention to capture the behavioral outcomes of work-related flow.

Multiscale Microbial Preservation and Biogeochemical Signals in a Modern Hot-Spring Siliceous Sinter Rich in CO2 Emissions, Krýsuvík Geothermal Field, Iceland

The microbial communities inferred in silica sinter rocks, based on multiscale morphological features (fabrics and textures) and the presence of lipid biomarkers and their carbon isotopic composition, are evaluated in the Krýsuvík geothermal area of Iceland. Close to vent environments (T > 75 °C and pH 1.7‒3), stream floors are capped with homogeneous vitreous crusts and breccia levels, with no distinct recognizable silicified microbes. About 4 m far from the vents (T 75‒60 °C and pH 3‒6) and beyond (T < 60 °C and pH 6‒7.6), microbial sinters, including wavy and palisade laminated and bubble fabrics, differ between abandoned meanders and desiccated ponds. Fabric and texture variances are related to changes in the ratio of filament/coccoid silicified microbes and associated porosity. Coatings of epicellular silica, less than 2 µm thick, favor identification of individual microbial filaments, whereas coalescence of opal spheres into agglomerates precludes recognition of original microbial textures and silicified microbes. Episodic fluctuations in the physico-chemical conditions of surface waters controlled the acidic hydrolysis of biomarkers. Wavy laminated fabrics from pond margins comprise fatty acids, mono- and dialkyl glycerol, mono- and diethers, monoalkyl glycerol esters and small traces of 10-methyl branched C16 and C18 fatty acids and archaeol, indicative of intergrowths of cyanobacteria, Aquificales, and sulfate reducing bacteria and methanogenic archaea. In contrast, wavy laminated fabrics from abandoned meanders and palisade laminated fabrics from ponds differ in their branched fatty acids and the presence vs. absence of bacteriohopanetetrol, reflecting different cyanobacterial contributions. δ13C values of biomarkers range from −22.7 to −32.9‰, but their values in the wavy (pond) and bubble fabrics have much wider ranges than those of the wavy (meander), palisade, and vitreous fabrics, reflecting dissolved inorganic carbon (DIC) sources and a decrease in 13C downstream outflow channels, with heavier values closer to vents and depleted values in ponds.

A new species of Sphenomorphus (Squamata: Scincidae) from Phu Quoc Island, Vietnam with a discussion of biogeography and character state evolution in the S. stellatus group

An integrative taxonomic analysis of the Sphenomorphus stellatus group recovered a newly discovered museum specimen from Phu Quoc Island, Kien Giang Province, Vietnam as a new species most closely related to S. preylangensis from Phnom Chi in central Cambodia, approximately 175 km to the northeast. Most notably, S. phuquocensis sp. nov. lacks the derived condition of having black dorsal stripes that diagnose S. annamiticus—the sister species to S. preylangensis plus S. phuquocensis sp. nov. A BioGeoBEARS analysis recovered the ancestor of the S. stellatus group to likely have ranged across forested regions on an exposed Sunda Shelf from southwestern Indochina to Peninsular Malaysia prior to diverging into northern and southern lineages separated by the Gulf of Thailand. Episodic fluctuations in sea levels and concomitant changes in the physiography of the Mekong Delta contributed to the fragmented distribution within and between species of the northern lineage. Sphenomorphus phuquocensis sp. nov. represents the second species of reptile endemic to Phu Quoc Island.

Diversity patterns of subterranean invertebrate fauna in calcretes of the Yilgarn Region, Western Australia

Calcrete aquifers are unique groundwater habitats containing stygobiontic species endemic to each calcrete. The evolutionary history of stygofauna suggests the calcretes in Western Australia contain multiple ancient lineages, yet populations experience episodic variation in rainfall patterns, with little-known ecological consequences. The aim of the present study was to document stygofaunal diversity patterns and determine whether they are influenced by rainfall events. The average taxon richness in boreholes peaked shortly after periods of high rainfall, and when dominant taxa were excluded, evenness decreased after periods of both high and low rainfall, indicating that dominant taxa are an important factor in driving the system. Strong abundance–distribution relationships reflected the commonality of taxon groups; common taxon groups had broad distributions and high abundance levels, whereas rare taxon groups had small distributions and low abundance. After periods of intermediate and low rainfall, taxon groups had narrower distributions and the maximum number of individuals per borehole was lower. Finally, the majority of boreholes did not show changes in evenness over the 11-year study period, suggesting a reasonably stable ecosystem with episodic fluctuations that can be attributed to rainfall events. The results of the present study indicate that diversity patterns within boreholes are driven episodically by both external and internal factors, such as rainfall and rapid borehole dominance respectively.

Development and evaluation of electroejaculation techniques in the Tasmanian devil (Sarcophilus harrisii)

Electroejaculation (EEJ) has been used successfully to collect samples suitable for genome resource banking from a variety of endangered wildlife species. Ejaculates can also be used to evaluate the reproductive potential of individuals and provide information on seminal characteristics to aid in the development of sperm cryopreservation techniques. Electroejaculation techniques used for marsupial and eutherian species were tested on Tasmanian devils (n = 35). Spermic ejaculates were collected in 54% (19/35) of EEJ attempts. Spermic ejaculates were low in volume (3.9 ± 6.5 × 102 µL, range 10–3000 µL) and contained low numbers of spermatozoa (3.3 ± 7.8 × 103 spermatozoa per ejaculate, range 6–33 000). The osmolality and pH of presumptive urine-free ejaculates were 389 ± 130 mOsm kg–1 (range 102–566) and 7.0 ± 0.9 (range 6.0–8.0), respectively. Prostatic bodies were observed in 79% (26/33) of ejaculates. Episodic fluctuations in serum testosterone concentrations were not detected during the EEJ procedure (P > 0.05). Increases observed in serum cortisol concentrations during EEJ were less (P < 0.05) than those observed after an adrenalcorticotropic hormone challenge and diurnal variation suggested that cortisol concentrations are greater during the day than at night (P < 0.05). This information can be used to provide range values for the future examination of basic endocrine responses and the adrenal–pituitary axis of this species. This study also demonstrated that spermatozoa-rich devil electroejaculates are more difficult to obtain and poorer in quality than those of other marsupials.

Time-integrated measurement of corticosteroids in saliva by oral diffusion sink technology

Saliva, as a medium for assessing adrenocortical function in humans, has many advantages and a few distinct disadvantages. Interpretation of measurements of saliva cortisol is complicated by the contamination of saliva by steroid-binding proteins from blood plasma, enzyme activity in the salivary gland that converts cortisol to cortisone, and the amplification in saliva of the episodic fluctuations in systemic cortisol concentrations. We describe a new measurement technology that rejects artifacts from contamination of saliva by plasma protein, provides for measurement of both cortisol and cortisone, and integrates episodic fluctuations in concentration over a period of hours. This oral diffusion sink technology may greatly enhance the reliable interpretation of corticosteroid concentrations measured in saliva.

Episodic prolactin and growth hormone secretion not related to the actual suckling activity in lactating rats

ABSTRACT In order to characterize the secretion pattern of prolactin and GH in freely behaving lactating rats, frequent serial blood samples were collected through indwelling atrial cannulae and their prolactin and GH concentrations determined by radioimmunoassay. At the time of blood sampling, physical contact with the pups was recorded. Plasma prolactin and GH levels showed episodic changes which were independent of each other and there was no apparent correlation between hormone levels and contact between mother and pups. The data suggest that there are episodic fluctuations in plasma prolactin and GH concentrations in lactating rats. These changes do not appear to be closely correlated with the proximity of the mother to her pups. J. Endocr. (1986) 111, 137–142

Ultradian glucocorticoid rhythms in monkeys and rats continue during stress

Previously we showed that rhesus monkeys have ultradian cortisol rhythms with periods of about 90 min that persist during the infusion of large amounts of adrenocorticotropin. The experiments reported here showed that rats exhibit ultradian corticosterone rhythms with a similar period (median period 61 min). However, rat ultradian corticosterone rhythms were distorted by large slow trends that had to be removed before the rhythm could be adequately assessed. The need for sophisticated trend removal suggests that physiological variables that have been described as exhibiting episodic fluctuations (e.g., human cortisol) may actually be periodic and ultradian. The ultradian glucocorticoid rhythm persisted during stress both in monkeys (median period 80 min) and rats (median period 52 min). However, the glucocorticoid stress response appeared to produce large slow trends in both monkeys and rats, indicating that environmental influences may introduce slow trends that make raw data difficult to evaluate. More importantly, the fact that ultradian glucocorticoid rhythms persist during stress provides further evidence of limits on the classical concept that glucocorticoid secretion is tightly and inseparably linked to hormonal events in the hypothalamic-pituitary unit.

Mapping episodic fluctuations in plasma LH in orchidectomized rats

Reports of the frequency of pulsatile LH release in orchidectomized rats are surprisingly variable. Estimates of the period between LH pulses vary from 18.5 to 250 min in nine reports from six laboratories, published in 1981-1983. In these studies, blood samples were drawn at intervals ranging from 2.5 to 60 min. We examined the relationship between estimated LH pulse frequency and blood-sampling interval. Six castrated male rats were cannulated, and blood samples were drawn at 2.5-min intervals through 4 h. Plasma LH levels were determined by radioimmunoassay. Using the data obtained at 2.5-min intervals, we simulated blood-sampling intervals of 5, 7.5, 10, 12.5, and 15 min by sequentially deleting data points. The original and simulated data sets were analyzed by both the PULSAR and Cycle Detector computer programs. The results show that as the sampling interval increased from 2.5 to 15 min, the apparent period of pulsatile LH release rose steadily from about 20 min to about 100 min. We found a high, positive correlation between blood-sampling interval and the apparent period of LH pulses. Estimates of LH pulse frequency in castrated male rats vary directly with the frequency at which blood samples are taken. Sampling intervals greater than 5 min in orchidectomized rats yield an LH pulse period that is most likely exaggerated.