AMPLIFICATION OF UTEROGLOBIN SECRETION BY ALTERNATING PROLACTIN-PROGESTERONE ADMINISTRATION

1989 ◽  
Vol 122 (3) ◽  
pp. R5-R6 ◽  
Author(s):  
J. C. Daniel ◽  
S. C. June ja
Keyword(s):  
Positive Feedback ◽  
Feedback Process ◽  
Study Support

ABSTRACT Long-term ovariectomized rabbits were given injections of progesterone and prolactin in an alternating sequence (progesterone for 5 days, prolactin for 4 days and progesterone for 5 days) to test the hypothesis that each of these hormones acts to increase the other's receptor, resulting in a positive feedback process whereby prolactin augments the progesterone-dependent increase in the mRNA for the uterine protein, uteroglobin. The results of this study support the hypothesis, in that the experimental rabbits produced exceptionally large concentrations of uteroglobin.

A Positive Feedback Process Related to the Rapid Development of an Extratropical Cyclone over the Kuroshio/Kuroshio Extension

2018 ◽  
Vol 146 (2) ◽  
pp. 417-433 ◽  
Author(s):  
Hidetaka Hirata ◽  
Ryuichi Kawamura ◽  
Masaya Kato ◽  
Taro Shinoda
Keyword(s):  
Water Vapor ◽  
Positive Feedback ◽  
Heat Supply ◽  
Rapid Development ◽  
Kuroshio Extension ◽  
Heat Fluxes ◽  
Latent Heating ◽  
Sensible Heat ◽  
Feedback Process ◽  
The Kuroshio

Abstract The active roles of sensible heat supply from the Kuroshio/Kuroshio Extension in the rapid development of an extratropical cyclone, which occurred in the middle of January 2013, were examined by using a regional cloud-resolving model. In this study, a control experiment and three sensitivity experiments without sensible and latent heat fluxes from the warm currents were conducted. When the cyclone intensified, sensible heat fluxes from these currents become prominent around the cold conveyor belt (CCB) in the control run. Comparisons among the four runs revealed that the sensible heat supply facilitates deepening of the cyclone’s central pressure, CCB development, and enhanced latent heating over the bent-back front. The sensible heat supply enhances convectively unstable conditions within the atmospheric boundary layer along the CCB. The increased convective instability is released by the forced ascent associated with frontogenesis around the bent-back front, eventually promoting updraft and resultant latent heating. Additionally, the sensible heating leads to an increase in the water vapor content of the saturated air related to the CCB through an increase in the saturation mixing ratio. This increased water vapor content reinforces the moisture flux convergence at the bent-back front, contributing to the activation of latent heating. Previous research has proposed a positive feedback process between the CCB and latent heating over the bent-back front in terms of moisture supply from warm currents. Considering the above two effects of the sensible heat supply, this study revises the positive feedback process.

scholarly journals Autocrine signaling by an Aplysia neurotrophin forms a presynaptic positive feedback loop

2018 ◽  
Vol 115 (47) ◽  
pp. E11168-E11177 ◽  
Author(s):  
Iksung Jin ◽  
Hiroshi Udo ◽  
Russell Nicholls ◽  
Huixiang Zhu ◽  
Eric R. Kandel ◽  
...  
Keyword(s):  
Positive Feedback ◽  
Feedback Loop ◽  
Autocrine Signaling ◽  
Positive Feedback Loop ◽  
Short Term Plasticity ◽  
Extracellular Signaling ◽  
Presynaptic Protein ◽  
Long Term Facilitation

Whereas short-term plasticity is often initiated on one side of the synapse, long-term plasticity involves coordinated changes on both sides, implying extracellular signaling. We have investigated the possible signaling role of an Aplysia neurotrophin (ApNT) in facilitation induced by serotonin (5HT) at sensory-to-motor neuron synapses in culture. ApNT is an ortholog of mammalian BDNF, which has been reported to act as either an anterograde, retrograde, or autocrine signal, so that its pre- and postsynaptic sources and targets remain unclear. We now report that ApNT acts as a presynaptic autocrine signal that forms part of a positive feedback loop with ApTrk and PKA. That loop stimulates spontaneous transmitter release, which recruits postsynaptic mechanisms, and presynaptic protein synthesis during the transition from short- to intermediate-term facilitation and may also initiate gene regulation to trigger the transition to long-term facilitation. These results suggest that a presynaptic ApNT feedback loop plays several key roles during consolidation of learning-related synaptic plasticity.

Driving Brand Equity With Radical Transparency

2017 ◽  
pp. 18-62 ◽  
Keyword(s):  
Business Model ◽  
Brand Equity ◽  
Positive Feedback ◽  
Perceived Quality ◽  
Brand Associations ◽  
Equity Model ◽  
Loyal Customers ◽  
Over Time

The main purpose of this chapter is to analyze the categories of brand equity assets through the prism of radical transparency. The results reveal that the brand equity requires investment and disappears over time if not maintained consistently with the selected business model and the company's values. The chapter is dedicated to systemize the theoretical and practical findings over the brand equity elements. Brand loyalty is the first element of the brand equity model. The benefits for the company which uses the radical transparency practices can be simply synthesized into one big advantage - satisfied and loyal customers who generate stable revenues and profits for the company in the long term. Radical transparency has a major impact on stimulating brand awareness as a factor that is particularly important in the sense that the brand must first enter into the considerations set. The company should be ready and open for cooperation with all interested parties and provide positive feedback whenever necessary. This enhances the perceived quality of the brand and the trust. The application of the radical transparency concept in the overall operation of the company enables the creation of a special set of brand associations that create long-lasting relationships with consumers, mixed with positive emotional mix that seals the success in the long term.

scholarly journals Role of Ural blocking in Arctic sea ice loss and its connection with Arctic warming in winter

2020 ◽  
Author(s):  
Dong-Jae Cho ◽  
Kwang-Yul Kim
Keyword(s):  
Sea Ice ◽  
Turbulent Flux ◽  
Longwave Radiation ◽  
Arctic Sea Ice ◽  
Sea Surface ◽  
Feedback Process ◽  
Arctic Warming ◽  
Open Sea

AbstractUral blocking (UB) is suggested as one of the contributors to winter sea ice loss in the Barents–Kara Seas (BKS). This study compares UB with Arctic warming (AW) in order to delineate the role of UB on winter sea ice loss and its potential link with AW. A detailed comparison reveals that UB and AW are partly linked on sub-seasonal scales via a two-way interaction; circulation produced by AW affects UB and advection induced by UB affects temperature in AW. On the other hand, the long-term impacts of AW and UB on the sea ice concentration in the BKS are distinct. In AW, strong turbulent flux from the sea surface warms the lower troposphere, increases downward longwave radiation, and broadens the open sea surface. This feedback process explains the substantial sea ice reduction observed in the BKS in association with long-term accelerating trend. Patterns of turbulent flux, net evaporation, and net longwave radiation at surface associated with UB are of opposite signs to those associated with AW, which implies that moisture and heat flux is suppressed as warm and moist air is advected from mid-latitudes. As a result, vertical feedback process is hindered under UB. The qualitative and quantitative differences arise in terms of their impacts on sea ice concentrations in the BKS, because strong turbulent flux from the open sea surface is a main driving force in AW whereas heat and moisture advection is a main forcing in UB.

scholarly journals Modulated Response of Subtropical Gyres: Positive Feedback Loop, Subharmonic Modes, Resonant Solar and Orbital Forcing

2018 ◽  
Vol 6 (3) ◽  
pp. 107 ◽  
Author(s):  
Jean-Louis Pinault
Keyword(s):  
Positive Feedback ◽  
Feedback Loop ◽  
Rossby Waves ◽  
Resonance Phenomenon ◽  
Polar Coordinates ◽  
Western Boundary ◽  
Orbital Forcing ◽  
Positive Feedback Loop ◽  
The Mean

Evidence of long-term variability in the upper ocean has emerged for two decades. Most of the issues discussed raise a lot of questions. What is the driver of the decadal oscillation of rainfall in Europe that has been observed since the end of the 20th century? How to explain low-frequency variability as observed in the Atlantic Multidecadal Oscillation (AMO)? More generally, how does solar and orbital forcing occur during very long-term climate change? The observations suggest that both a positive feedback loop amplifies the effects of the insolation gradient on the climate system and a resonance phenomenon occurs, filtering out some frequencies in favour of others. Throughout this paper, some answers to these problems are given from a new concept based on the modulated response of subtropical gyres to solar and orbital forcing. Subtropical gyres turn out to be the main driver of long-term climate variability because they tightly control, via the western boundary currents, heat transport from the tropics into middle and high latitudes. Specifically, the theoretical foundations of long-period Rossby waves winding around the subtropical gyres are laid, suggested by the observations of persistent sea surface temperature anomalies at mid-latitudes. Multi-frequency Gyral Rossby Waves (GRWs) exhibit properties resulting from their annular structure and their coupling. Using a β-cone approximation, the momentum equations are solved in polar coordinates. The gradient β of the Coriolis parameter depends on the mean radius of the annulus and remains constant all around the latter. GRWs result from the variation in the Coriolis Effect with the mean radius of the annulus. The speed of the anti-cyclonically wind-driven circulation being higher than the phase velocity of cyclonically propagating GRWs, amplified forcing effects occur as well as resonances for periods consistent with the observations.

EFFECTS OF GONADECTOMY AND OESTRADIOL TREATMENT ON PLASMA LUTEINIZING HORMONE CONCENTRATIONS IN THE MARMOSET MONKEY, CALLITHRIX JACCHUS

1978 ◽  
Vol 76 (2) ◽  
pp. 271-281 ◽  
Author(s):  
J. K. HODGES
Keyword(s):  
Luteinizing Hormone ◽  
Negative Feedback ◽  
Positive Feedback ◽  
Pituitary Hormones ◽  
Male And Female ◽  
Oestradiol Treatment ◽  
Marmoset Monkey ◽  
Biphasic Effect ◽  
Clear Increase

A heterologous double-antibody radioimmunoassay for marmoset LH is described in detail. The system uses NIAMDD rat LH-I-1 for iodination, NIAMDD rat LH-RP-1 as standard and anti-ovine rabbit LH 610V serum. The assay measures the level of marmoset LH in plasma and shows a maximum cross-reaction (B/Bo = 50%) of < 0·3% with other rat, human or bovine pituitary hormones. The heterologous assay has been applied to the measurement of the level of LH in the marmoset after gonadectomy and after the subsequent implantation of oestradiol-17β capsules. A clear increase in the concentration of LH in the plasma was observed by day 3 after gonadectomy and in most animals the level reached a plateau by day 9. The rates of increase in the concentration of LH and the maximum levels attained after gonadectomy were similar in male and female marmosets. The secretion of LH in long-term gonadectomized marmosets was episodic. In four of the marmosets studied, the frequency of the pulsatile discharges of LH was circhoral, whereas in the remaining five animals the frequency could not be determined. Subcutaneous implants containing oestradiol-17β were seen to have a biphasic effect on the secretion of LH in all gonadectomized marmosets. After a transient increase in the concentration of LH (positive feedback) on day 1, levels fell markedly by day 4 and were undetectable 8 days after the implants were introduced (negative feedback).

Purely Endoscopic Resection of Colloid Cysts

2008 ◽  
Vol 62 (suppl_1) ◽  
pp. ONS51-ONS56 ◽  
Author(s):  
Jeremy D.W. Greenlee ◽  
Charles Teo ◽  
Ali Ghahreman ◽  
Bernard Kwok
Keyword(s):  
Endoscopic Resection ◽  
Third Ventricle ◽  
Colloid Cyst ◽  
Foramen Of Monro ◽  
The Third ◽  
Colloid Cysts ◽  
Study Support

Abstract Objective: To further assess the safety and long-term efficacy of endoscopic resection of colloid cysts of the third ventricle. Methods: A retrospective review of a series of 35 consecutive patients (18 male, 17 female) with colloid cysts treated by endoscopic surgery was undertaken. Results: The mean patient age was 32.4 years (range, 11–54 yr). Headache was the most common presenting symptom (22 patients). The average tumor size was 18 mm (range, 3–50 mm). The endoscopic technique could not be completed in six patients, necessitating conversion to an open craniotomy and a transcortical approach to the colloid cyst. All patients had histologically confirmed colloid cysts of the third ventricle, and complete resection of the lesion was confirmed macroscopically and radiologically in all patients. There were no deaths. Two patients developed aseptic meningitis without any permanent sequelae. One patient developed unilateral hydrocephalus attributable to obstruction of the foramen of Monro, which was treated with endoscopic septum pellucidotomy. The median follow-up period was 88 months (range, 10–132 mo). There was one asymptomatic radiological recurrence. No seizures occurred after surgery. Conclusion: The results of this study support the role of endoscopic resection in the treatment of patients with colloid cysts as a safe and effective modality. In some cases, conversion to an open procedure may be required. Additional follow-up will be required to continue to address the duration of lesion-free survival.

scholarly journals The test of self‐conscious affect: internal structure, differential scales and relationships with long‐term affects

2001 ◽  
Vol 15 (6) ◽  
pp. 449-463 ◽  
Author(s):  
Johnny R. J. Fontaine ◽  
Patrick Luyten ◽  
Paul De Boeck ◽  
Jozef Corveleyn
Keyword(s):  
Internal Structure ◽  
Factor Structure ◽  
Factor Analyses ◽  
Confirmatory Factor Analyses ◽  
Self Evaluation ◽  
Confirmatory Factor ◽  
Study Support

Item analyses and confirmatory factor analyses on the Test of Self‐Conscious Affect (TOSCA), in a student (N = 723) and an adult (N = 891) sample, supported the theorized four factor structure of proneness to reparation, negative self‐evaluation, externalizing blame and unconcern. However, two‐fifth of the items did not empirically differentiate between two or more factors. Differential TOSCA scales, including only differentiating TOSCA items, were constructed and related to measures of long‐term affect, depression, anxiety, and anger. Both the pattern and size of correlations of the original and the differential TOSCA scales were almost identical. Results of this study support the interpretation of TOSCA guilt as a measure of a tendency to reparation associated with guilt and TOSCA shame as a measure of a tendency to global negative self‐evaluation. Copyright © 2001 John Wiley & Sons, Ltd.

scholarly journals Metal-induced bacterial interactions promote diversity in river-sediment microbiomes

2020 ◽  
Vol 96 (6) ◽  
Author(s):  
Valentine Cyriaque ◽  
Augustin Géron ◽  
Gabriel Billon ◽  
Joseph Nesme ◽  
Johannes Werner ◽  
...  
Keyword(s):  
Community Assembly ◽  
Species Interactions ◽  
Metal Contamination ◽  
Control Site ◽  
Rrna Gene ◽  
Health Issues ◽  
Study Support ◽  
Contamination Event ◽  
Microbial Community Assembly

ABSTRACT Anthropogenic metal contamination results in long-term environmental selective pressure with unclear impacts on bacterial communities, which comprise key players in ecosystem functioning. Since metal contamination poses serious toxicity and bioaccumulation issues, assessing their impact on environmental microbiomes is important to respond to current environmental and health issues. Despite elevated metal concentrations, the river sedimentary microbiome near the MetalEurop foundry (France) shows unexpected higher diversity compared with the upstream control site. In this work, a follow-up of the microbial community assembly during a metal contamination event was performed in microcosms with periodic renewal of the supernatant river water. Sediments of the control site were gradually exposed to a mixture of metals (Cd, Cu, Pb and Zn) in order to reach similar concentrations to MetalEurop sediments. Illumina sequencing of 16S rRNA gene amplicons was performed. Metal-resistant genes, czcA and pbrA, as well as IncP plasmid content, were assessed by quantitative PCR. The outcomes of this study support previous in situ observations showing that metals act as community assembly managers, increasing diversity. This work revealed progressive adaptation of the sediment microbiome through the selection of different metal-resistant mechanisms and cross-species interactions involving public good-providing bacteria co-occurring with the rest of the community.

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