scholarly journals Consequences of acute and long-term removal of neuromodulatory input on the episodic gastric rhythm of the crab Cancer borealis

2015 ◽  
Vol 114 (3) ◽  
pp. 1677-1692 ◽  
Author(s):  
Albert W. Hamood ◽  
Eve Marder
Keyword(s):  
Pattern Generation ◽  
Stomatogastric Nervous System ◽  
Cancer Borealis ◽  
Cycle Frequency ◽  
Motor Behaviors ◽  
Rhythmic Motor ◽  
Insight Into ◽  
Phase Relationships

For decades, the episodic gastric rhythm of the crustacean stomatogastric nervous system (STNS) has served as an important model system for understanding the generation of rhythmic motor behaviors. Here we quantitatively describe many features of the gastric rhythm of the crab Cancer borealis under several conditions. First, we analyzed spontaneous gastric rhythms produced by freshly dissected preparations of the STNS, including the cycle frequency and phase relationships among gastric units. We find that phase is relatively conserved across frequency, similar to the pyloric rhythm. We also describe relationships between these two rhythms, including a significant gastric/pyloric frequency correlation. We then performed continuous, days-long extracellular recordings of gastric activity from preparations of the STNS in which neuromodulatory inputs to the stomatogastric ganglion were left intact and also from preparations in which these modulatory inputs were cut (decentralization). This allowed us to provide quantitative descriptions of variability and phase conservation within preparations across time. For intact preparations, gastric activity was more variable than pyloric activity but remained relatively stable across 4–6 days, and many significant correlations were found between phase and frequency within animals. Decentralized preparations displayed fewer episodes of gastric activity, with altered phase relationships, lower frequencies, and reduced coordination both among gastric units and between the gastric and pyloric rhythms. Together, these results provide insight into the role of neuromodulation in episodic pattern generation and the extent of animal-to-animal variability in features of spontaneously occurring gastric rhythms.

Investment opportunities for student housing in Europe

2018 ◽  
Vol 36 (6) ◽  
pp. 578-584 ◽  
Author(s):  
Nick French ◽  
Geetha Bhat ◽  
Gurpreet Matharu ◽  
Filipe Ortigão Guimarães ◽  
David Solomon
Keyword(s):  
Student Housing ◽  
European Countries ◽  
Content Type ◽  
Market Requirements ◽  
Investment Opportunities ◽  
Property Markets ◽  
Practical Implications ◽  
Insight Into

Purpose The purpose of this paper is to provide an insight into how the demographic of international and home students in the major university cities in three European countries (France, Spain and Germany) offers investors an opportunity to provide students housing. This paper looks at how a mobile and demanding student clientele now demands, well priced, good quality and purpose built accommodation during their studies at University. This offers a good property investment opportunity. Design/methodology/approach This practice briefing is an overview of the demand factors that are creating opportunities in France, Spain and Germany. Findings This paper analyses the link between the under provision of purpose built student housing and an opportunity to develop a long-term cash flow producing investment asset. Practical implications The role of the property developers and investors is to successfully identify trends and demands and provide the assets that meet the market requirements. This paper looks at the meeting point in three major European countries for this latent and, currently, poorly served demand. Originality/value This provides guidance on how investment opportunities develop in non-traditional property markets.

The utility of relationships in the creation and maintenance of an event portfolio

2018 ◽  
Vol 36 (2) ◽  
pp. 260-275 ◽  
Author(s):  
Donna M. Kelly ◽  
Sheranne Fairley
Keyword(s):  
Process Model ◽  
Structured Interviews ◽  
Content Type ◽  
Key Stakeholders ◽  
Strategic Goals ◽  
The Creation ◽  
Practical Implications ◽  
Insight Into

Purpose Event portfolios promote synergies among events and stakeholders within a destination in order to maximise resources. The purpose of this paper is to examine the role of relationships in the creation and maintenance of an event portfolio using the four stages of Parvatiyar and Sheth’s (2000) process model of relationship marketing: formation, management and governance, performance evaluation, and evolution. Design/methodology/approach Nine semi-structured interviews were conducted with tourism and government stakeholders involved in the creation and maintenance of an event portfolio within a single destination. Findings The destination outlined clear strategic goals through an event strategy. An Events Board was established to bring together key stakeholders from tourism, events, and government to oversee the development of an event portfolio. The Events Board gave advice to relevant tourism and government stakeholders on which events they should provide funding. Developing relationships was not a stated objective, but the Events Board realised the importance of relationships to create and maintain the destination’s event portfolio. Long-term funding contracts were used as a mechanism to establish relationships and were an impetus for interaction. Relationships were also maintained through dedicated staff who managed the relationships between the destination stakeholders and the events. Practical implications Understanding factors that contribute to the successful creation and maintenance of event portfolios can inform destination stakeholders who are responsible for generating tourism through events. Originality/value Limited research has examined the creation and maintenance of event portfolios. This study provides insight into the central importance of relationships in creating and maintaining an event portfolio.

scholarly journals The carbon dioxide signal from the COVID-19 lock-down

2020 ◽  
Author(s):  
John Reid
Keyword(s):  
Mixed Layer ◽  
Deep Ocean ◽  
Weather Conditions ◽  
Anthropogenic Emissions ◽  
Temporary Reduction ◽  
Local Weather ◽  
Global Carbon ◽  
Insight Into

Abstract Two unintended experiments provide insight into the role of anthropogenic emissions in the global carbon cycle. One was the temporary reduction in emissions during the COVID-19 lock-down. The other was the emission of a radioactive isotope of carbon during the testing of nuclear weapons in the 1950s and the abrupt cessation of these tests in 1963. Together they imply the existence of two distinct reservoirs which exchange carbon with the atmosphere, viz.: the mixed layer and the deep ocean. Exchanges with the former are noisy because they are influenced by sea surface temperature which, in turn, depends on local weather conditions. They completely mask any variations caused by the COVID-19 lock-down. Exchanges with the latter are steady, long-term and uninfluenced by the weather. They result in half the carbon content of the atmosphere and mixed layer being replaced every eleven years.

Unravelling some mysteries of porcine respiratory and reproductive syndrome virus (PRRSV) infections: new insights from modelling studies

2009 ◽  
Vol 2009 ◽  
pp. 30-30
Author(s):  
A Doeschl-Wilson ◽  
I Kyriazakis ◽  
L Galina-Pantoja
Keyword(s):  
Immune Response ◽  
Host Immune Response ◽  
Growing Pigs ◽  
Modelling Studies ◽  
Porcine Respiratory ◽  
Insight Into

Porcine reproductive and respiratory syndrome (PRRS) is an endemic pig disease in most European countries, causing respiratory distress, fever and growth reductions in growing pigs and increased litter mortality in sows. The disease is characterised by exceptionally long-term viral persistence within the host, a weak innate host immune response and delayed adaptive host immune response, and large between animal variation in the immune response (Murtaugh et al., 2004). Although numerous in-vitro and in-vivo studies produced valid insight into the fine details of the virus dynamics and its interaction with the host’s immune response, several fundamental questions concerning the role of diverse immune components and host genetics remain unanswered. In this study mathematical models were developed to investigate the role of diverse processes caused by the virus or the immune response on the infection characteristics.

Information Technologies Socialise Geographies

2010 ◽  
Vol 12 (3) ◽  
pp. 1-27 ◽  
Author(s):  
Gilbert Ahamer ◽  
Josef Strobl
Keyword(s):  
Information Technologies ◽  
Communicative Action ◽  
Structural Evolution ◽  
World Views ◽  
Strategic Role ◽  
Geographic Information Sciences ◽  
Insight Into ◽  
Common World

One of the ethical tasks and practical effects of IT is bridging and spanning different locations, thereby “socialising” across diverse “geographies of understanding”. A dozen documented case studies use IT (especially Geographic Information Sciences) in distance learning. The underlying conceptual model of a network society combined with empirical research on long-term civilisational and economic evolution leads to a general understanding of Information Technologies as facilitators of a multi-perspectivist and multi-disciplinary construction of world views (m:n type of science). Such a synopsis of education, structural evolution, social spaces and institutional change provides insight into IT’s strategic role of facilitating consensus building and constructing common world views that can socially converge (“socialise”) isolated cultures of understanding. “Geography” is here seen as a provider of world views that emerge from communicative action. The presented cases in this paper span both geographic locations as well as constructed cultures of understanding.

Long-Term Outcomes of Grade I–II Skull Base Chondrosarcoma: An Insight into the Role of Surgery and Radiotherapy

2021 ◽  
Author(s):  
Hirotaka Hasegawa ◽  
Avital Perry ◽  
Christopher S. Graffeo ◽  
Jamie J. Van Gompel ◽  
Colin L. Driscoll ◽  
...  
Keyword(s):  
Skull Base ◽  
Long Term Outcomes ◽  
Insight Into

Catecholamines and pituitary function. IV. Effects of low-dose dopamine infusion and long-term bromocriptine treatment on the abnormal thyrotroph (TSH) dynamics in patients with pathological hyperprolactinaemia

1986 ◽  
Vol 111 (2) ◽  
pp. 154-161 ◽  
Author(s):  
Ildo Nicoletti ◽  
Paolo Filipponi ◽  
Leone Fedeli ◽  
Franca Ambrosi ◽  
Camillo Giammartino ◽  
...  
Keyword(s):  
Anterior Pituitary ◽  
Low Dose ◽  
Physiological Role ◽  
Serum Concentrations ◽  
Trh Test ◽  
Synthesis Inhibitor ◽  
Tsh Secretion ◽  
Insight Into

Abstract. In order to gain further insight into the role of dopamine (DA) in the control of TSH release and to investigate whether an increased or defective DA inhibition on pituitary thyrotrophs may be considered responsible for the abnormal TSH dynamics in pathological hyperprolactinaemia, we examined the effect of low-dose DA infusion on TRH stimulated TSH secretion in normally cycling women and in patients with pathological hyperprolactinaemia. The effect of long-term bromocriptine therapy on TSH dynamics was also evaluated in a selected group of hyperprolactinaemic women. Fifty-two hyperprolactinaemic patients with no other signs of pituitary or thyroid dysfunction had significantly higher mean TSH serum concentrations and mean TSH peak values after TRH administration than 75 healthy controls. Furthermore, the TSH rises induced by the DA-synthesis inhibitor α-methyl-p-tyrosine (AMPT, 500 mg orally) were enhanced in both prolactinoma and 'idiopathic hyperprolactinaemia' patients as compared with controls. There was a positive correlation between the TRH- and AMPT-induced TSH rises in the hyperprolactinaemic group. Low-dose DA infusion (0.1 μg/kg min) reduced TSH response to TRH in both regularly cycling women and patients with hyperprolactinaemic amenorrhoea. Long-term bromocriptine therapy (2.5 mg tid over 60– 150 days) not only normalized serum Prl levels, but also reduced the TSH response to TRH in 7 hyperprolactinaemic women who had presented exaggerated TSH responses to the basal TRH test. These findings confirm that DA plays a physiological role in the inhibition of TSH release, probably at the level of the anterior pituitary. The fact that both low-dose DA infusion and long-term bromocriptine treatment effectively reduced TSH release in hyperprolactinaemic patients seems to indicate that endogenous DA inhibition of pituitary thyrotrophs is reduced rather than enhanced in pathological hyperprolactinaemia.

scholarly journals Long-term outcomes of grade I/II skull base chondrosarcoma: an insight into the role of surgery and upfront radiotherapy

2021 ◽  
Author(s):  
Hirotaka Hasegawa ◽  
Kunal Vakharia ◽  
Christopher S. Graffeo ◽  
Matthew L. Carlson ◽  
Bruce E. Pollock ◽  
...  
Keyword(s):  
Skull Base ◽  
Long Term Outcomes ◽  
Insight Into

scholarly journals A model of the enteric neural circuitry underlying the generation of rhythmic motor patterns in the colon: the role of serotonin

2017 ◽  
Vol 312 (1) ◽  
pp. G1-G14 ◽  
Author(s):  
Terence Keith Smith ◽  
Sang Don Koh
Keyword(s):  
Glial Cells ◽  
Motor Neurons ◽  
Circular Muscle ◽  
Tonic Inhibition ◽  
Excitatory Postsynaptic Potential ◽  
Motor Patterns ◽  
Motor Behaviors ◽  
Rhythmic Motor ◽  
Colonic Motor

We discuss the role of multiple cell types involved in rhythmic motor patterns in the large intestine that include tonic inhibition of the muscle layers interrupted by rhythmic colonic migrating motor complexes (CMMCs) and secretomotor activity. We propose a model that assumes these motor patterns are dependent on myenteric descending 5-hydroxytryptamine (5-HT, serotonin) interneurons. Asynchronous firing in 5-HT neurons excite inhibitory motor neurons (IMNs) to generate tonic inhibition occurring between CMMCs. IMNs release mainly nitric oxide (NO) to inhibit the muscle, intrinsic primary afferent neurons (IPANs), glial cells, and pacemaker myenteric pacemaker interstitial cells of Cajal (ICC-MY). Mucosal release of 5-HT from enterochromaffin (EC) cells excites the mucosal endings of IPANs that synapse with 5-HT descending interneurons and perhaps ascending interneurons, thereby coupling EC cell 5-HT to myenteric 5-HT neurons, synchronizing their activity. Synchronized 5-HT neurons generate a slow excitatory postsynaptic potential in IPANs via 5-HT7 receptors and excite glial cells and ascending excitatory nerve pathways that are normally inhibited by NO. Excited glial cells release prostaglandins to inhibit IMNs (disinhibition) to allow full excitation of ICC-MY and muscle by excitatory motor neurons (EMNs). EMNs release ACh and tachykinins to excite pacemaker ICC-MY and muscle, leading to the simultaneous contraction of both the longitudinal and circular muscle layers. Myenteric 5-HT neurons also project to the submucous plexus to couple motility with secretion, especially during a CMMC. Glial cells are necessary for switching between different colonic motor behaviors. This model emphasizes the importance of myenteric 5-HT neurons and the likely consequence of their coupling and uncoupling to mucosal 5-HT by IPANs during colonic motor behaviors.

scholarly journals The Role of Service-Learning in Information Systems Education

10.28945/4797 ◽  
2021 ◽  
Vol 18 ◽  
pp. 103-119
Author(s):  
Tana Feyt ◽  
Gwamaka Mwalemba
Keyword(s):  
Information Systems ◽  
Service Learning ◽  
South African ◽  
Course Evaluations ◽  
Future Research ◽  
Socially Responsible ◽  
Civic Mindedness ◽  
Insight Into

Aim/Purpose: The aim of this study is to explore the role of service-learning in Information Systems (IS) education. Background: While the use of modern technologies presents many operational benefits, such as the lowering of the costs, it may also aggravate social-economic is-sues. IS professionals should account for these issues as well as exhibit the skills demanded by modern-day employers. Hence, why there is a need for IS educators to adopt a new pedagogy that supports the development of more holistic and socially responsible IS graduates. Methodology: In this qualitative exploratory case study, two IS service-learning courses at a South African university were studied. Interviews, course evaluations, and reflection essays were analyzed to gain insight into the implications that service-learning may have for students. Contribution: This study contributes to IS education research by advancing discussions on the role of service-learning in providing learning outcomes such as the development of important skills in IS, civic-mindedness, and active participation in society. Findings: The findings showed that the courses had different implications for students developing skills that are important in IS and becoming civic-minded due to the variation in their design and implementation. Recommendations for Practitioners: It is recommended that IS educators present their courses in the form of service-learning with a careful selection of readings, projects, and reflection activities. Recommendations for Researchers: IS education researchers are advised to conduct longitudinal studies to gain more insight into the long-term implications that service-learning may have for IS students. Impact on Society: This paper provides insight into how IS students may gain social agency and a better understanding of their role in society. Future Research: It is recommended that future research focus on mediating factors and the implications that service-learning may have for IS students in the long-term.

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