Phase-related Differences Research Articles

Phase-related differences in egg production of the migratory locust regulated by differential oosorption through microRNA-34 targeting activinβ

Outbreaks of locust plagues result from the long-term accumulation of high-density egg production. The migratory locust, Locusta migratoria, displays dramatic differences in the egg-laid number with dependence on population density, while solitarious locusts lay more eggs compared to gregarious ones. However, the regulatory mechanism for the egg-laid number difference is unclear. Herein, we confirm that oosorption plays a crucial role in the regulation of egg number through the comparison of physiological and molecular biological profiles in gregarious and solitarious locusts. We find that gregarious oocytes display a 15% higher oosorption ratio than solitarious ones. Activinβ (Actβ) is the most highly upregulated gene in the gregarious terminal oocyte (GTO) compared to solitarious terminal oocyte (STO). Meanwhile, Actβ increases sharply from the normal oocyte (N) to resorption body 1 (RB1) stage during oosorption. The knockdown of Actβ significantly reduces the oosorption ratio by 13% in gregarious locusts, resulting in an increase in the egg-laid number. Based on bioinformatic prediction and experimental verification, microRNA-34 with three isoforms can target Actβ. The microRNAs display higher expression levels in STO than those in GTO and contrasting expression patterns of Actβ from the N to RB1 transition. Overexpression of each miR-34 isoform leads to decreased Actβ levels and significantly reduces the oosorption ratio in gregarious locusts. In contrast, inhibition of the miR-34 isoforms results in increased Actβ levels and eventually elevates the oosorption ratio of solitarious locusts. Our study reports an undescribed mechanism of oosorption through miRNA targeting of a TGFβ ligand and provides new insights into the mechanism of density-dependent reproductive adaption in insects.

The utilization of cluster externalities and recessionary shocks

AbstractIn this article, we examine the impact of cluster externalities on the economic performance of firms. Specifically, we focus on how the utilization of these externalities by firms is affected by the macroeconomic instability caused by the recessionary shock of 2008/2009 and on how the impact of the crisis affects firms with different combinative capabilities. Using data from more than 16,000 manufacturing and business service firms located in 390 German regions, we employ within-firm regression techniques to estimate the impact of cross-level interactions between firm- and cluster-level determinants on phase-related differences in firm performance between a pre-crisis (2004–2007) and a crisis period (2009–2011). Our empirical results suggest that firms particularly benefit from the interaction of broad combinative capabilities and variety-driven cluster externalities, thereby implying that externalities are effectively utilized by firms. Furthermore, the results indicate that both strength and direction of these cross-level interactions strongly depend on the prevailing macroeconomic cycle: while the utilization of cluster externalities works best within a stable macroeconomic environment (2004–2007), it is seemingly interrupted when being exposed to economic turmoil (2009–2011). Yet, the crisis-induced interruption of the utilization is mainly restricted to the national recession in 2009. As soon as the macroeconomic pressure diminishes (2010–2011), we observe a reversion of the utilization mechanisms to the pre-crisis level.

Changes in pulp sensitivity across the menstrual cycle in healthy women and women with temporomandibular disorders.

Menstrual cycle may contribute to experimental pain measures in healthy women and women with chronic pain. The present study aimed to investigate variation in pulp sensitivity across the menstrual cycle in healthy women and women with temporomandibular disorders (TMD) and to explore the effect of TMD pain and psychosocial variables on the pulp response. This longitudinal study involved 47 regularly menstruating women aged 20-45, 24 healthy and 23 with diagnosed painful TMD. The electric and cold stimuli were performed by electric pulp tester and refrigerant spray, respectively, on mandibular lateral incisors, in five menstrual phases (menstrual, follicular, periovulatory, luteal and premenstrual). Research Diagnostic Criteria for TMD were used to assess TMD, chronic pain, depression and somatisation. Regression analysis was performed to investigate the effect of the predictor variables on the pulp sensitivity. Significant phase-related differences were observed for pain intensity to cold stimuli. Higher pain sensitivity was reported in menstrual in comparison with luteal phase (P=.019) among healthy women, and in menstrual in comparison with follicular (P=.033), periovulatory (P=.003) and luteal (P=.007) phases in TMD women. No significant differences were recorded for electric stimuli. Regression analysis identified depression as the determinant of cold and electric response in menstrual phase, regardless of age and presence of TMD. Menstrual phase in healthy and TMD women with regular menstrual cycle is characterised with higher pulp sensitivity to cold stimuli. Depressive symptoms independently influence pulp response in this phase.

Avoidance Learning Across the Menstrual Cycle: A Conceptual Replication.

Hormonal transitions across the menstrual cycle may modulate human reward processing and reinforcement learning, but previous results were contradictory. Studies assessed relatively small samples (n < 30) and exclusively used within-subject designs to compare women in hormonally distinct menstrual cycle phases. This increased the risk of sporadic findings and results may have been disproportionally affected by expectancy effects. Also, replication studies are widely missing, which currently precludes any reliable inferences. The present study was intended as a conceptual replication of a previous study [(1), Neuropsychologia 84; n = 15]. There, we had observed a reduction in avoidance learning capacity when women were in the high estradiol state of the late follicular phase as compared to the mid luteal phase with enhanced progesterone influence. These results conformed to the idea that estradiol and progesterone may antagonistically modulate dopaminergic transmission as a dopamine agonist and antagonist, respectively. Heightened progesterone in the luteal phase thereby supported the ability to learn from the negative outcomes of one's actions, while the follicular rise in estradiol interfered with this capacity. Here, we re-examined the above described within-subject difference between the follicular and the luteal phase in a between-subjects design. Seventy-five women were tested once with a probabilistic feedback learning task, while being either in the follicular (36 women) or luteal phase (39 women), and were compared for phase-related differences in behavior. Secondly, we combined the new data with data from three previous studies from our laboratory that used the same task and menstrual cycle phases. This meta-analysis included only data from the first test day, free of any biasing expectancy effects. Both analyses demonstrated the consistency of the decline in avoidance learning in the follicular relative to the luteal phase. We also showed that this decline reliably occurred in all of the included samples. Altogether, these results provide evidence for the consistency of a behavioral difference and its apparent association with a transient change in hormonal state that occurs in the natural menstrual cycle. Our findings may also open new avenues for the development of reliable between-subjects test protocols in menstrual cycle research.

Cluster Externalities, Firm Capabilities, and the Recessionary Shock: How the Macro-to-Micro-Transition Shapes Firm Performance During Stable Times and Times of Crisis

In this paper, we examine the macro-to-micro-transition of cluster externalities to firms and how it is affected by the macroeconomic instability caused by the recessionary shock of 2008/2009. Using data from 16,166 manufacturing and business services firms nested in 390 German regions, we employ within-firm regression techniques to estimate the impact of cross level interactions between firm- and cluster-level determinants on phase-related differences in firm performance between a pre-crisis (2004-2007) and a crisis period (2009-2011). The empirical results validate the existence of a macro-to-micro-transition that evolves best in the case of broad firm-level capabilities and variety-driven externalities. Furthermore, the results indicate that the transition strongly depends on the macroeconomic cycle. While the transition particularly benefits from a stable macroeconomic environment (2004-2007), its mechanisms are interrupted when being exposed to economic turmoil (2009-2011). Yet, the crisis induced interruption of the transition is mainly restricted to the national recession in 2009. As soon as the macroeconomic pressure diminishes (2010-2011), we observe a reversion of the transmission mechanisms to the pre-crisis level. Our study contributes to the existing literature by corroborating previous findings that the economic performance of firms depends on a working macro-to-micro transition of external resources, which presupposes sufficient cluster externalities and adequate firm-level combinative capabilities. In contrast to previous studies on this topic, the transition mechanism is not modeled as time-invariant. Instead, it is coupled to the prevailing macroeconomic regime.

The Effect of Density-Dependent Phase on the Locust Gut Bacterial Composition.

The desert locust demonstrates density-dependent phase polyphenism: For extended periods it appears in a non-aggregating, non-migrating phenotype, known as the solitary phase. When circumstances change, solitary individuals may aggregate and transform to the gregarious phenotype, which have a strong propensity for generating large swarms. Previous reports have suggested a role for gut-bacteria derived volatiles in the swarming phenomenon, and suggested that locusts are capable of manipulating their gut microbiome according to their density-dependent phases. Here, we directly tested this hypothesis for the first time. Using locusts of both phases from well-controlled laboratory cultures as well as gregarious field-collected individuals; and high-throughput sequencing. We characterized the hindgut bacterial community composition in the two phases of the desert locust. Our findings demonstrate that laboratory-reared gregarious and solitary locusts maintain a stable core of Enterobacter. However, while different generations of gregarious locust experience shifts in their Enterobacter’s relative abundance; the solitary locusts maintain a stable gut microbiome, highly similar to that of the field-collected locusts. Tentative phase differences in wild populations’ microbiome may thus be an indirect effect of environmental or other factors that push the swarming individuals to homogenous gut bacteria. We therefore conclude that there are phase-related differences in the population dynamics of the locust hindgut bacterial composition, but there is no intrinsic density-dependent mechanism directly affecting the gut microbiome.

Natural variation in testosterone is associated with hypoalgesia in healthy women.

Sex differences in pain are well established, with women reporting greater incidence of clinical pain and heightened responsivity to experimental pain stimuli relative to men. Sex hormones (ie, estrogens, progestins, androgens) could contribute to extant differences in pain sensitivity between men and women. Despite this, there has been limited experimental research assessing the relationship between pain and sex hormones. The purpose of this study was to extend previous research and examine the association between sex hormones and nociceptive processing in healthy women. A total of 40 healthy women were tested during the mid-follicular, ovulatory, and late-luteal phases of the menstrual cycle (testing order counterbalanced). Salivary estradiol, progesterone, and testosterone were collected at each testing session and pain was examined from electrocutaneous threshold/tolerance, ischemia threshold/tolerance, and McGill Pain Questionnaire-Short Form ratings of noxious stimuli. Nociceptive flexion reflex threshold was assessed as a measure of spinal nociception. Overall, there were no significant menstrual phase-related differences in pain outcomes. Nonetheless, variability in testosterone (and to a lesser degree estradiol) was associated with pain; testosterone was antinociceptive, whereas estradiol was pronociceptive. No hormone was associated with nociceptive flexion reflex threshold. Although future research is needed to replicate and extend these findings to clinical populations (ie, chronic pain, premenstrual dysphoric disorder), results from the present study indicate that menstrual phase-related changes in sex hormones have minimal influence on experimental pain. However, individual differences in testosterone may play a protective role against pain in healthy women.

Interpersonal coordination and ball dynamics in futsal (indoor football)

Here, we report an investigation of the patterned movement behavior of players for a specific sub-phase of the game of futsal, namely when the goalkeeper for the attacking team is substituted with an extra outfield player. The movement trajectories of the ball and players were recorded in both lateral and longitudinal directions and investigated using relative phase analysis. Some differences in phase relations between different playing dyads were noted, indicating specificity of phase attractions, or otherwise, for certain players. In general terms, the defenders demonstrated strong in-phase attractions with the ball and with each other, whereas weaker phase attractions, indicated by increased relative phase variability, were observed for the attackers and ball, as well as between attackers themselves. These results demonstrate different coordination dynamics for the defending and attacking dyads, from which we interpret evidence for different playing sub-systems consistent with different team objectives linked together in an overarching game structure. In keeping with dynamical systems theory for complex systems, we view this sub-phase of futsal as being characterized by coordinated behavior patterns that emerge as a result of self-organizing processes. These dynamic patterns are generated within functional constraints, with players and teams exerting mutual influence on each other.

α-Adrenergic control of blood flow during exercise: effect of sex and menstrual phase

Sex differences exist in autonomic control of the cardiovascular system. This study was designed to directly test sex or female menstrual phase-related differences in α-adrenergic control of blood flow during exercise. We hypothesized that women would exhibit reduced α-adrenergic vasoconstriction compared with men during exercise; in addition, women would constrict less during the early luteal than the early follicular phase of the female menses. Young men (n = 10) were studied once and women (n = 9) studied twice, once during the early follicular phase and once during the early luteal phase of female menses. We measured forearm blood flow (FBF; Doppler ultrasound of the brachial artery) during rest and steady-state dynamic exercise (15 and 30% of maximal voluntary contraction, 20 contractions/min). A brachial artery catheter was inserted for the local administration of α-adrenergic agonists [phenylephrine (PE; α(1)) or clonidine (CL; α(2))]. Blood flow responses to exercise [forearm vascular conductance (FVC)] were similar between all groups. At rest, infusion of PE or CL decreased FVC in all groups (40-60% reduction). Vasoconstriction to PE was abolished in all groups at 15 and 30% exercise intensity. Vasoconstriction to CL was reduced at 15% and abolished at 30% intensity in all groups; women had less CL-induced constriction during the early luteal than early follicular phase (P < 0.017, 15% intensity). These results indicate that vasodilator responses to forearm exercise are comparable between men and women and are achieved through similar paths of α-adrenergic vascular control at moderate intensities; this control may differ at low intensities specific to the female menstrual phase.

Menstrual cycle modulation of medial temporal activity evoked by negative emotion

Previous studies have indicated phase-related differences in HPA activity and amygdala responsiveness in women, such that the response to negative emotional images is reduced during high-estrogen phases of the menstrual cycle. Other research has indicated an opposite effect of exogenous progesterone, increasing amygdala activity at some doses. However, no study to date has assessed the response of the brain's arousal circuitry to negative images during the luteal phase, when both progesterone and estrogen levels are elevated. To address this question, 17 naturally cycling women were each scanned during the early follicular and mid-luteal phases of the cycle, and response to IAPS images was assessed by fMRI. The results indicated significantly increased activity in hippocampus and amygdala during mid-luteal scans when compared to scans in the early follicular phase. These findings suggest that progesterone-mediated effects dominate during the luteal phase, and further suggest that estrogen and progesterone may play opposing roles in modulating the brain's arousal circuitry.

Menstrual phase-related differences in the pulsatility index on the central retinal artery suggest an oestrogen vasodilatation effect that antagonizes with progesterone

The actual effect of steroid hormones on cerebral microcirculation is still controversial. Therefore, the aim of our study was to investigate vascular flow variations in the central retinal artery that may exist during the ovulatory menstrual cycle. A total of 34 healthy women were included in this observational, longitudinal, and prospective study. All participants were submitted to dopplerfluxometric evaluation of the eyes in order to study the pulsatility index (PI) of the central retinal arteries, during four phases of the menstrual cycle: early follicular, mid follicular, periovulatory, and mid luteal phases. Subjects' ages ranged from 14 to 47 years old (mean: 29.7 ± 10.1) and PI did not differ among age groups. The PI of the central retinal artery was different among the four phases of the menstrual cycle. PI showed a significant decrease from early follicular phase (1.72) to mid follicular phase (1.57) (p = 0.037), and was similar during periovulatory phase (1.56) and significantly increased in mid luteal phase (1.70). After that it returned to the values observed in the early follicular phase. Our results suggest the existence of an oestrogen vasodilatation effect on the central retinal artery that is menstrual phase-related and antagonized by progesterone.

Proteomics Analysis of Lactobacillus casei Zhang, a New Probiotic Bacterium Isolated from Traditional Home-made Koumiss in Inner Mongolia of China

Lactobacillus casei Zhang, isolated from traditional home-made koumiss in Inner Mongolia of China, was considered as a new probiotic bacterium by probiotic selection tests. We carried out a proteomics study to identify and characterize proteins expressed by L. casei Zhang in the exponential phase and stationary phase. Cytosolic proteins of the strain cultivated in de Man, Rogosa, and Sharpe broth were resolved by two-dimensional gel electrophoresis using pH 4-7 linear gradients. The number of protein spots quantified from the gels was 487 +/- 21 (exponential phase) and 494 +/- 13 (stationary phase) among which a total of 131 spots were identified by MALDI-TOF/MS and/or MALDI-TOF/TOF according to significant growth phase-related differences or high expression intensity proteins. Accompanied by the cluster of orthologous groups (COG), codon adaptation index (CAI), and GRAVY value analysis, the study provided a very first insight into the profile of protein expression as a reference map of L. casei. Forty-seven spots were also found in the study that showed statistically significant differences between exponential phase and stationary phase. Thirty-three of the spots increased at least 2.5-fold in the stationary phase in comparison with the exponential phase, including 19 protein spots (e.g. Hsp20, DnaK, GroEL, LuxS, pyruvate kinase, and GalU) whose intensity up-shifted above 3.0-fold. Transcriptional profiles were conducted to confirm several important differentially expressed proteins by using real time quantitative PCR. The analysis suggests that the differentially expressed proteins were mainly categorized as stress response proteins and key components of central and intermediary metabolism, indicating that these proteins might play a potential important role for the adaptation to the surroundings, especially the accumulation of lactic acid in the course of growth, and the physiological processes in bacteria cell.

Expression of VEGF-A, Flt-1, and Flk-1 in the arterial endothelial cells of the uterine broad ligament throughout the estrous cycle

The aim of the present study was to determine the immunoreactivity of vascular endothelial growth factor (VEGF-A) and its two receptors, viz., Flt-1 (fms-like tyrosine kinase) and Flk-1 (fetal liver kinase), on the surface of endothelial cells of the uterine artery and its branches and of the arcuate arteries in the area of the uterine broad ligament during various phases of the estrous cycle in the pig. We also investigated their expression to determine whether this was phase-related. The highest immunoreactivity for VEGF-A was observed in the uterine artery and arcuate arteries at the early luteal phase and in the branches of the uterine artery during the follicular phase of the estrous cycle. The strongest immunostaining intensity of Flt-1 was found in the uterine artery and its branches at the follicular phase and in arcuate arteries at the mid-luteal phase, whereas Flk-1 immunostaining was at its highest in the uterine artery at the mid-luteal phase and in the branches of the uterine artery and arcuate arteries at the follicular phase. Additionally, VEGF-A expression was assessed by semi-quantitative Western blot analysis, which revealed significantly higher levels of VEGF-A protein during the early luteal and the follicular phase of the estrous cycle (P < 0.001). The phase-related differences in the immunoreactivity and expression of VEGF-A and VEGF receptors suggest that these factors are hormone-dependent during the estrous cycle in the pig.

Comparison of growth phase on Salmonella enterica serovar Typhimurium invasion in an epithelial cell line (IPEC J2) and mucosal explants from porcine small intestine

Salmonella Typhimurium DT104 is a zoonotic enteropathogen of increasing concern for human health. In this study, the influence of growth phase on invasiveness of a S. Typhimurium DT104 field isolate and two reference strains (SL1344 and ATCC 14028) was compared in IPEC J2 cells and mucosal explants from porcine ileum. Internalized bacteria were quantified by a gentamicin resistance assay. After 90 min of exposure to the apical aspect of epithelial monolayers or luminal surface of explants, internalization of all S. Typhimurium strains in mid-logarithmic phase of bacterial growth was comparable. Internalization of stationary phase bacteria was reduced relative to log phase bacteria, with DT104 exhibiting the greatest decrease. Growth phase-related differences in S. Typhimurium invasion are similar in porcine intestinal epithelial cells and mucosal explants, but may be greater in multidrug-resistant strains.

Gonadotropin-releasing hormone-stimulated gonadotropin levels in women with premenstrual dysphoria

Despite consistent evidence that premenstrual dysphoria (PMD) is not characterized by abnormalities in basal ovarian hormone secretion, the possibility remains that PMD is associated with an abnormality in the regulation of the hypothalamic-pituitary-ovarian (HPO) axis. We studied HPO axis regulation in 11 women with prospectively confirmed PMD and 20 asymptomatic controls, during both the follicular and luteal phases of the menstrual cycle. Plasma levels of the gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), were obtained before and after stimulation with gonadotropin-releasing hormone (GnRH) (100 μg intravenously). Potential diagnostic- and menstrual cycle phase-related differences in basal and plasma hormone levels were analyzed by repeated-measures analysis of variance. No significant differences were observed between women with PMD and controls in either basal or stimulated levels of FSH and LH. Stimulated FSH was significantly increased and stimulated LH was significantly decreased during the follicular compared with the luteal phase in both women with PMD and controls. These data are consistent with prior findings of normal basal reproductive hormone levels in women with PMD. Our data suggest the absence in women with PMD of an abnormality of dynamic ovarian function as measured by GnRH stimulation.

Phase-Related Differences in Mating Strategy of a Locust (Orthoptera: Acrididae)

The migratory locust, Locusta migratoria L., shows phase polymorphism in which various morphological, physiological, and behavioral traits change according to population density. Information about the reproductive behavior, particularly sperm competition and male-female associations, has been obtained mainly from crowd-reared locusts. To understand the reproductive strategy in different phases, i.e., solitarious versus gregarious phase, we compared the P2 (i.e., the proportion of offspring sired by the second male to mate), length of pre- and postcopulatory mounting and length of copulation between solitarious (isolated-reared) and gregarious (crowd-reared) adults of this locust. We observed that solitarious adults had a higher P2 value, shorter precopulatory mounting, and longer copulation than gregarious adults. A significant positive correlation between length of precopulatory mounting and copulation was found in gregarious adults, but not in solitarious adults in the two geographic strains used. Little or no postcopulatory mounting was observed in either phase. Pairing of crowd-reared males and isolated-reared females indicated that males did not play a decisive role in determining these behaviors. The results demonstrate phase-related differences in reproductive strategy that are likely to be adaptive for locusts facing a large variation in chance of encounters between the two sexes.

Food mixing strategies in the desert locust: effects of phase, distance between foods, and food nutrient content

AbstractFood mixing strategies were compared in the cryptically coloured, relatively sedentary ‘solitarious’ and the highly mobile, conspicuously coloured ‘gregarious’ phases of the desert locust, Schistocerca gregaria. Based on phase related differences in behaviour and nutritional regulatory responses, we predicted that solitarious nymphs, compared to gregarious nymphs, would move less between nutritionally complementary foods, particularly as the distance between the foods increased. We manipulated the nutritional composition [protein (p) and digestible carbohydrate (c) content] of two foods in an experimental arena and varied the distance between the foods using a factorial experimental design. Results indicated that in general, solitarious nymphs showed greater fidelity to individual food dishes than did gregarious insects (i.e., they concentrated their feeding mainly on one dish). However, results also demonstrated that for both phases fidelity to a particular food dish increased as the distance between the dishes increased, and that the number of switches between dishes decreased with increasing distance. In the smallest arenas, though, gregarious nymphs switched more frequently between the two food dishes than solitarious nymphs, even when the two dishes contained the same, near‐optimal food (p18:c24). When challenged by having the two dishes either placed furthest apart (2 m) or more divergent in nutritional composition (p29:c13 vs. p7:c35), insects of both phases regulated protein intake more strongly than carbohydrate intake, by eating more from the dish containing higher‐protein food.

Modulation of Body Temperature, Interleukin-6 and Leptin by Oral Contraceptive Use

Objectives: This study examined the hypothesis that oral contraceptives (OC) influence the production of thermoregulatory cytokines, i.e. interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), soluble glycoprotein 130 (s-gp130) and leptin, and that OC-induced changes in oral temperature (T_oral) are associated with changes in plasma concentrations of these cytokines. To determine if increases in T_oral are part of a cytokine-driven inflammatory (acute-phase) response, circulating concentrations of the hepatic acute-phase protein C-reactive protein (CRP) were also measured. Methods: Morning T_oral were measured and blood samples were collected from 18 women (19- to 22-years-old) on two occasions: Once during active pill usage (quasi-luteal (QL) phase) and once when no active pills were taken (quasi-follicular (QF) phase). Plasma cytokine and CRP concentrations were measured by immunoassay. Results: T_oral and plasma leptin were higher during QL phase (36.4 ± 0.1°C, 9.3 ± 1.0 ng/ml) than QF phase (36.1 ± 0.1°C, p < 0.01; 7.5 ± 0.7 ng/ml, p < 0.01). Increases in T_oral correlated with increases in plasma leptin (R = 0.55, p = 0.02) and with progestin dose (R = 0.47, p = 0.05) individually as well as with leptin and progestin combined in a multiple regression (R = 0.68, p = 0.01). Plasma IL-6 correlated with progestin dose (R = 0.62, p = 0.006). Although there were no phase-related differences in plasma IL-6, sIL-6R, s-gp130, or CRP, the variation in CRP between individuals correlated with the IL-6 agonist/antagonist ratio combined with progestin dose in a multiple regression (R = 0.71, p = 0.01). Conclusions: These results (a) implicate leptin in basal thermoregulation; (b) indicate that progestins have a significant influence on circulating IL-6 concentrations, and (c) are consistent with the concept that plasma CRP concentrations depend upon combined influences of progestins and bioavailable IL-6.

Pattern amplitude is related to pattern imitation during the song development of nightingales

Song intensity has been neglected in studies on the song development of oscine birds. We analysed this ontogenetic trajectory in the singing of hand-reared nightingales, Luscinia megarhynchos, from their earliest song vocalizations (subsong) through plastic singing, to their adult full song. Embedded in an age-dependent increase in overall sound level, nightingales showed systematic amplitude differences within their song performances. Episodes of song performance containing many imitations of acquired model songs (IPA phases) were produced with a higher amplitude than episodes with only few or no imitations (UPA phases). Further analysis of song patterns revealed that this difference was mainly due to the high number of imitations occurring during the IPA phases. However, unidentified patterns (UPA) that were vocalized during IPA phases had a significantly higher vocal amplitude than UPAs vocalized during UPA phases. This finding indicates that, besides pattern-related amplitude differences, performance phases as a whole also differed in amplitude. The consistent pattern- and phase-related differences in sound level indicate that the control of vocal amplitude should be viewed as an integrative part of the vocal learning process.

Short-term weight gain in abstaining women smokers.

Although most studies of weight gain following smoking cessation assess long-term change, weight gain during the critical period immediately following cessation may be more salient to the smoker for whom fear of weight gain constitutes a serious barrier to cessation. The current study examined weight change in 20 highly dependent women smokers provided with monetary incentives to abstain for 1 week, along with concomitant changes in cotinine. Abstaining smokers (n = 7) gained 3.1 pounds, compared with 0.3 pounds in women who continued to smoke (n = 13). Across all subjects, change was significantly negatively correlated with final plasma cotinine concentration and marginally negatively correlated with percent cotinine reduction. Weight gain in women abstainers in the luteal phase of the menstrual cycle exceeded that in women abstainers in the follicular phase; a significant interaction such that continuing smokers showed no phase-related differences in weight suggests that the effect was not an artifact of perimenstrual increases in eating or fluid retention. Although long-term weight gain has been shown to be positively associated with success in quitting, little is known about the effects of short-term weight gain. Since many weight-concerned individuals either do not attempt to quit or terminate their quit attempts very early, it may be that if weight gain can be postponed beyond the first few fragile days of cessation, women with strong weight concerns may actually be good candidates for success.