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Kowalczuk, Iwona, and Jerzy Gębski. "Factors influencing restaurant tipping behaviour – the case of Poland." International Journal of Culture, Tourism and Hospitality Research 15, no. 2 (January 19, 2021): 172–82. http://dx.doi.org/10.1108/ijcthr-10-2019-0189.
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Purpose This paper aims to contribute to the literature that discusses consumer tipping behaviour in eating establishments. Because there is no detailed research into this issue with regard to consumers in Central and East European countries, the authors conducted research aimed at learning about the tipping behaviour of the Poles. Design/methodology/approach This study was carried out in 2018, using the computer-assisted web interviewing method, for a sample of 1,000 people. Six research questions were asked: How often the Poles give tips in eating establishments? What is an average size of a tip? What determinants influence the frequency and magnitude of tips? Who is likely to give a tip every one to two visits? Who is likely to tip more than the standard 10%? What influences the reasons why Polish consumers tend to tip? Findings The findings show the strong relationships between both a consumers’ tipping frequency and magnitude and the frequency at which these consumers eat out. This study also implicates income and education as essential factors influencing tipping behaviour and the lack of gender effect on consumers’ decision to tip. It was also noticed that such reasons as the quality of service, a taste of the dishes and a belief that it is proper to tip have a significant impact on the frequency of giving the tips. A significant diversity of the reasons’ meaning for tipping among Polish consumers depending upon their age was also stated. Research limitations/implications It would be interesting to compare the results of the current study with studies concerning consumer tipping behaviours in other Central and Eastern European countries historically and culturally similar to Poland to investigate whether the specifics of tipping behaviour noticed in Poland apply elsewhere. Originality/value This study shows the specifics of Polish people’s tipping behaviour and partially fulfills the gap in the knowledge of this aspect of consumers’ from Central and Eastern Europe behaviour. The obtained results suggest that with the increasing incomes and the widespread use of food services, tipping is likely to become more common in Poland. Furthermore, the pragmatic reasons for tipping will become more important than social and psychological motivators.
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Saayman, Melville, and Andrea Saayman. "Understanding Tipping Behaviour — An Economic Perspective." Tourism Economics 21, no. 2 (April 2015): 247–65. http://dx.doi.org/10.5367/te.2014.0448.
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Klose, Ann Kristin, Volker Karle, Ricarda Winkelmann, and Jonathan F. Donges. "Emergence of cascading dynamics in interacting tipping elements of ecology and climate." Royal Society Open Science 7, no. 6 (June 2020): 200599. http://dx.doi.org/10.1098/rsos.200599.
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In ecology, climate and other fields, (sub)systems have been identified that can transition into a qualitatively different state when a critical threshold or tipping point in a driving process is crossed. An understanding of those tipping elements is of great interest given the increasing influence of humans on the biophysical Earth system. Complex interactions exist between tipping elements, e.g. physical mechanisms connect subsystems of the climate system. Based on earlier work on such coupled nonlinear systems, we systematically assessed the qualitative long-term behaviour of interacting tipping elements. We developed an understanding of the consequences of interactions on the tipping behaviour allowing for tipping cascades to emerge under certain conditions. The (narrative) application of these qualitative results to real-world examples of interacting tipping elements indicates that tipping cascades with profound consequences may occur: the interacting Greenland ice sheet and thermohaline ocean circulation might tip before the tipping points of the isolated subsystems are crossed. The eutrophication of the first lake in a lake chain might propagate through the following lakes without a crossing of their individual critical nutrient input levels. The possibility of emerging cascading tipping dynamics calls for the development of a unified theory of interacting tipping elements and the quantitative analysis of interacting real-world tipping elements.
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Tse, Alan C. "Tipping behaviour: a disconfirmation of expectation perspective." International Journal of Hospitality Management 22, no. 4 (December 2003): 461–67. http://dx.doi.org/10.1016/j.ijhm.2003.07.002.
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Kruger, M., and M. Saayman. "The dining and tipping behaviour of Black South Africans: a segmentation approach." Southern African Business Review 20, no. 1 (March 27, 2019): 336–64. http://dx.doi.org/10.25159/1998-8125/6055.
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The literature on dining and tipping behaviour has focused mostly on the United States of America (USA), while minimal research has been conducted in African countries. While there is a negative and grounded perception surrounding black diners being poor tippers in the USA, hardly any research has focused on the dining or tipping behaviour of this dining market from a developing country perspective. The intention of this exploratory research was to fill the current knowledge gap by segmenting black South Africans on the basis of their motives for dining out and to determine the differences in the dining and tipping behaviour of the different segments. To target potential black diners, a visitor survey was conducted at the Cape Town International Jazz Festival. A total of 256 usable questionnaires were returned and included in the analysis. Socialisation, gastronomy enjoyment, lifestyle and escape and status were identified as the four motives for dining out. Based on these motives, different black dining segments were identified and an OSI (Occasionalists, Socialisers and Indulgers) typology of diners proposed. The dining and tipping behaviour of these dining segments are furthermore influenced by several factors, with clear implications for both the server and restaurateurs. The results shed light on the dining and tipping behaviour of black South African diners and showed that this dining market cannot be regarded as bad tippers.
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Pruitt, Jonathan N., Andrew Berdahl, Christina Riehl, Noa Pinter-Wollman, Holly V. Moeller, Elizabeth G. Pringle, Lucy M. Aplin, et al. "Social tipping points in animal societies." Proceedings of the Royal Society B: Biological Sciences 285, no. 1887 (September 19, 2018): 20181282. http://dx.doi.org/10.1098/rspb.2018.1282.
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Animal social groups are complex systems that are likely to exhibit tipping points—which are defined as drastic shifts in the dynamics of systems that arise from small changes in environmental conditions—yet this concept has not been carefully applied to these systems. Here, we summarize the concepts behind tipping points and describe instances in which they are likely to occur in animal societies. We also offer ways in which the study of social tipping points can open up new lines of inquiry in behavioural ecology and generate novel questions, methods, and approaches in animal behaviour and other fields, including community and ecosystem ecology. While some behaviours of living systems are hard to predict, we argue that probing tipping points across animal societies and across tiers of biological organization—populations, communities, ecosystems—may help to reveal principles that transcend traditional disciplinary boundaries.
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Callan, Roger J., and Kirstie Tyson. "Tipping Behaviour in Hospitality Embodying a Comparative Prolegomenon of English and Italian Customers." Tourism and Hospitality Research 2, no. 3 (October 2000): 242–61. http://dx.doi.org/10.1177/146735840000200305.
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The paper introduces tipping in a historical perspective, explaining and contrasting tipping habits in England and elsewhere. The case for tipping or service charges is presented. A review of the literature explores those factors that have been found to influence tipping behaviour. The methodology for a comparative introductory study of English and Italian hotel restaurant customers is explained, together with the results. Due to the limited sample sizes, care should be taken when interpreting the results, as differences identified between the English and Italian samples could be abated due to the regional differences within each country. With this qualification, the paper concludes that Italians rated influencing factors more highly than did the English and found attractiveness of server, speed of service and prompt bill delivery to be particularly important. By contrast, English customers generally rated qualities of the product to be more important than the characteristics of the server as influences on tip size.
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Lundeberg, Mark B., and Mark RA Shegelski. "Long tipping times of a quantum rod." Canadian Journal of Physics 84, no. 1 (January 1, 2006): 19–36. http://dx.doi.org/10.1139/p06-003.
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We calculate the tipping time of a quantum rod that has a height several times that of the edge length of its square base. We use an expression for the tipping time that has heuristic value, and gives the average time at which, upon measurement, the initially balanced rod is found to tip. We use two methods to calculate the tipping time. One method is to examine the "late time" behaviour of the quantum state of the center of mass of the rod by using an equation that has the form of the time-independent Schrödinger equation except that it involves a "complex energy." The other method uses energy resonances in the eigenstates of the Hamiltonian to determine the tipping time. We use the well-known WentzelKramersBrillouin approximation to calculate the energy eigenstates. With these methods, we obtain expressions for the tipping time that are valid for very long tipping times. PACS Nos.: 03.65.w, 03.65.Xp
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Ong, Cheng Boon. "Tipping points in Dutch big city neighbourhoods." Urban Studies 54, no. 4 (September 29, 2016): 1016–37. http://dx.doi.org/10.1177/0042098015619867.
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Micro-level studies using individual and household data have shown that residential location choices are influenced by neighbourhood ethnic composition. Using three conurbation samples in the Netherlands – Amsterdam metropolitan area, Rotterdam-The Hague metropolitan area and the country’s largest conurbation, the ‘Randstad’ urban agglomeration – this paper analyses the evolution of neighbourhood ethnic composition as a social interaction outcome of disaggregated household behaviour. The potential ‘tipping point’ in neighbourhood ethnic composition, beyond which ‘white flight’ (or the departure of native or advantaged households) occurs, is tested. The share in neighbourhood population of native Dutch and Western minority did not exhibit the hypothesised ‘tipping’ behaviour in its growth rate with respect to initial share of non-Western minority. This paper argues that the large social housing sector, centralised tax regime, and strong regulatory role of the state in housing and urban planning, are the main explanatory factors for the relative constancy in Dutch neighbourhood ethnic composition.
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Barkan, Rachel, and Aviad Israeli. "Testing servers' roles as experts and managers of tipping behaviour." Service Industries Journal 24, no. 6 (November 2004): 91–108. http://dx.doi.org/10.1080/0264206042000299194.
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Hinchliffe, Kaitlin J., and Marilyn A. Campbell. "Tipping Points: Teachers’ Reported Reasons for Referring Primary School Children for Excessive Anxiety." Journal of Psychologists and Counsellors in Schools 26, no. 1 (December 11, 2015): 84–99. http://dx.doi.org/10.1017/jgc.2015.24.
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The current study explored the reasons that primary school teachers reported were tipping points for them in deciding whether or not and when to refer a child to the school student support team for excessive anxiety. Twenty teachers in two Queensland primary schools were interviewed. Content analysis of interview transcripts revealed six themes reflecting teachers’ perceived reasons for deciding to refer anxious children: (1) impact on learning; (2) atypical child behaviour; (3) repeated difficulties that do not improve over time; (4) poor response to strategies; (5) teachers’ need for support; and (6) information from parents/carers. Teachers considered different combinations of reasons and had many different tipping points for making a referral. Both teacher- and system-level influences impacted referral decisions. Implications and future research are discussed.
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BISSELL, J. J., C. C. S. CAIADO, M. GOLDSTEIN, and B. STRAUGHAN. "COMPARTMENTAL MODELLING OF SOCIAL DYNAMICS WITH GENERALISED PEER INCIDENCE." Mathematical Models and Methods in Applied Sciences 24, no. 04 (January 28, 2014): 719–50. http://dx.doi.org/10.1142/s0218202513500656.
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A generalised compartmental method for investigating the spread of socially determined behaviour is introduced, and cast in the specific context of societal smoking dynamics with multiple peer influence. We consider how new peer influence terms, acting in both the rate at which smokers abandon their habit, and the rate at which former smokers relapse, can affect the spread of smoking in populations of constant size. In particular, we develop a three-population model (comprising classes of potential, current, and former smokers) governed by multiple incidence transfer rates with linear frequency dependence. Both a deterministic system and its stochastic analogue are discussed: in the first we demonstrate that multiple peer influence not only modifies the number of steady-states and nature of their asymptotic stability, but also introduces a new kind of non-linear "tipping-point" dynamic; while in the second we use recently compiled smoking statistics from the Northeast of England to investigate the impact of systemic uncertainty on the potential for societal "tipping". The generality of our assumptions mean that the results presented here are likely to be relevant to other compartmental models, especially those concerned with the transmission of socially determined behaviours.
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Livina, V. N., and T. M. Lenton. "A recent tipping point in the Arctic sea-ice cover: abrupt and persistent increase in the seasonal cycle since 2007." Cryosphere 7, no. 1 (February 12, 2013): 275–86. http://dx.doi.org/10.5194/tc-7-275-2013.
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Abstract. There is ongoing debate over whether Arctic sea ice has already passed a "tipping point", or whether it will do so in the future. Several recent studies argue that the loss of summer sea ice does not involve an irreversible bifurcation, because it is highly reversible in models. However, a broader definition of a "tipping point" also includes other abrupt, non-linear changes that are neither bifurcations nor necessarily irreversible. Examination of satellite data for Arctic sea-ice area reveals an abrupt increase in the amplitude of seasonal variability in 2007 that has persisted since then. We identified this abrupt transition using recently developed methods that can detect multi-modality in time-series data and sometimes forewarn of bifurcations. When removing the mean seasonal cycle (up to 2008) from the satellite data, the residual sea-ice fluctuations switch from uni-modal to multi-modal behaviour around 2007. We originally interpreted this as a bifurcation in which a new lower ice cover attractor appears in deseasonalised fluctuations and is sampled in every summer–autumn from 2007 onwards. However, this interpretation is clearly sensitive to how the seasonal cycle is removed from the raw data, and to the presence of continental land masses restricting winter–spring ice fluctuations. Furthermore, there was no robust early warning signal of critical slowing down prior to the hypothesized bifurcation. Early warning indicators do however show destabilization of the summer–autumn sea-ice cover since 2007. Thus, the bifurcation hypothesis lacks consistent support, but there was an abrupt and persistent increase in the amplitude of the seasonal cycle of Arctic sea-ice cover in 2007, which we describe as a (non-bifurcation) "tipping point". Our statistical methods detect this "tipping point" and its time of onset. We discuss potential geophysical mechanisms behind it, which should be the subject of further work with process-based models.
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Blennow, Kristina, and Johannes Persson. "To Mitigate or Adapt? Explaining Why Citizens Responding to Climate Change Favour the Former." Land 10, no. 3 (March 1, 2021): 240. http://dx.doi.org/10.3390/land10030240.
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Why do citizens’ decisions made because they favour the mitigation of climate change outnumber those made because they favour adaptation to its impacts? Using data collected in a survey of 338 citizens of Malmö, Sweden, we tested two hypotheses. H1: the motivation for personal decisions because they favour adaptation to the impacts of climate change correlates with the decision-making agent´s knowledge of specific local impacts of climate change, and H2: the motivation for personal decisions because they favour mitigation of climate change correlates with the risk perception of the decision-making agent. While decisions made because they favour mitigation correlated with negative net values of expected impacts of climate change (risk perception), decisions made because they favour adaptation correlated with its absolute value unless tipping point behaviour occurred. Tipping point behaviour occurs here when the decision-making agent abstains from decisions in response to climate change in spite of a strongly negative or positive net value of expected impacts. Hence, the decision-making agents´ lack of knowledge of specific climate change impacts inhibited decisions promoting adaptation. Moreover, positive experiences of climate change inhibited mitigation decisions. Discussing the results, we emphasised the importance of understanding the drivers of adaptation and mitigation decisions. In particular, we stress that attention needs to be paid to the balance between decisions solving problems ‘here and now’ and those focusing on the ‘there and then’.
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Ivkov, Milan, Sanja Božić, and Ivana Blešić. "The effect of service staff’s verbalized hospitality towards group diner’s additional purchases and tipping behaviour." Scandinavian Journal of Hospitality and Tourism 19, no. 1 (December 14, 2017): 82–94. http://dx.doi.org/10.1080/15022250.2017.1415168.
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Merker, Jochen, Benjamin Kunsch, and Gregor Schuldt. "Nonlinear Compartment Models with Time-Dependent Parameters." Mathematics 9, no. 14 (July 14, 2021): 1657. http://dx.doi.org/10.3390/math9141657.
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A nonlinear compartment model generates a semi-process on a simplex and may have an arbitrarily complex dynamical behaviour in the interior of the simplex. Nonetheless, in applications nonlinear compartment models often have a unique asymptotically stable equilibrium attracting all interior points. Further, the convergence to this equilibrium is often wave-like and related to slow dynamics near a second hyperbolic equilibrium on the boundary. We discuss a generic two-parameter bifurcation of this equilibrium at a corner of the simplex, which leads to such dynamics, and explain the wave-like convergence as an artifact of a non-smooth nearby system in C0-topology, where the second equilibrium on the boundary attracts an open interior set of the simplex. As such nearby idealized systems have two disjoint basins of attraction, they are able to show rate-induced tipping in the non-autonomous case of time-dependent parameters, and induce phenomena in the original systems like, e.g., avoiding a wave by quickly varying parameters. Thus, this article reports a quite unexpected path, how rate-induced tipping can occur in nonlinear compartment models.
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Moffatt, H. K., and Yoshifumi Kimura. "Towards a finite-time singularity of the Navier–Stokes equations Part 1. Derivation and analysis of dynamical system." Journal of Fluid Mechanics 861 (December 31, 2018): 930–67. http://dx.doi.org/10.1017/jfm.2018.882.
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The evolution towards a finite-time singularity of the Navier–Stokes equations for flow of an incompressible fluid of kinematic viscosity$\unicode[STIX]{x1D708}$is studied, starting from a finite-energy configuration of two vortex rings of circulation$\pm \unicode[STIX]{x1D6E4}$and radius$R$, symmetrically placed on two planes at angles$\pm \unicode[STIX]{x1D6FC}$to a plane of symmetry$x=0$. The minimum separation of the vortices,$2s$, and the scale of the core cross-section,$\unicode[STIX]{x1D6FF}$, are supposed to satisfy the initial inequalities$\unicode[STIX]{x1D6FF}\ll s\ll R$, and the vortex Reynolds number$R_{\unicode[STIX]{x1D6E4}}=\unicode[STIX]{x1D6E4}/\unicode[STIX]{x1D708}$is supposed very large. It is argued that in the subsequent evolution, the behaviour near the points of closest approach of the vortices (the ‘tipping points’) is determined solely by the curvature$\unicode[STIX]{x1D705}(\unicode[STIX]{x1D70F})$at the tipping points and by$s(\unicode[STIX]{x1D70F})$and$\unicode[STIX]{x1D6FF}(\unicode[STIX]{x1D70F})$, where$\unicode[STIX]{x1D70F}=(\unicode[STIX]{x1D6E4}/R^{2})t$is a dimensionless time variable. The Biot–Savart law is used to obtain analytical expressions for the rate of change of these three variables, and a nonlinear dynamical system relating them is thereby obtained. The solution shows a finite-time singularity, but the Biot–Savart law breaks down just before this singularity is realised, when$\unicode[STIX]{x1D705}s$and$\unicode[STIX]{x1D6FF}/\!s$become of order unity. The dynamical system admits ‘partial Leray scaling’ of just$s$and$\unicode[STIX]{x1D705}$, and ultimately full Leray scaling of$s,\unicode[STIX]{x1D705}$and$\unicode[STIX]{x1D6FF}$, conditions for which are obtained. The tipping point trajectories are determined; these meet at the singularity point at a finite angle. An alternative model is briefly considered, in which the initial vortices are ovoidal in shape, approximately hyperbolic near the tipping points, for which there is no restriction on the initial value of the parameter$\unicode[STIX]{x1D705}$; however, it is still the circles of curvature at the tipping points that determine the local evolution, so the same dynamical system is obtained, with breakdown again of the Biot–Savart approach just before the incipient singularity is realised. The Euler flow situation ($\unicode[STIX]{x1D708}=0$) is considered, and it is conjectured on the basis of the above dynamical system that a finite-time singularity can indeed occur in this case.
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Przybylski, Andrew K., and Netta Weinstein. "Violent video game engagement is not associated with adolescents' aggressive behaviour: evidence from a registered report." Royal Society Open Science 6, no. 2 (February 2019): 171474. http://dx.doi.org/10.1098/rsos.171474.
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In this study, we investigated the extent to which adolescents who spend time playing violent video games exhibit higher levels of aggressive behaviour when compared with those who do not. A large sample of British adolescent participants ( n = 1004) aged 14 and 15 years and an equal number of their carers were interviewed. Young people provided reports of their recent gaming experiences. Further, the violent contents of these games were coded using official EU and US ratings, and carers provided evaluations of their adolescents' aggressive behaviours in the past month. Following a preregistered analysis plan, multiple regression analyses tested the hypothesis that recent violent game play is linearly and positively related to carer assessments of aggressive behaviour. Results did not support this prediction, nor did they support the idea that the relationship between these factors follows a nonlinear parabolic function. There was no evidence for a critical tipping point relating violent game engagement to aggressive behaviour. Sensitivity and exploratory analyses indicated these null effects extended across multiple operationalizations of violent game engagement and when the focus was on another behavioural outcome, namely, prosocial behaviour. The discussion presents an interpretation of this pattern of effects in terms of both the ongoing scientific and policy debates around violent video games, and emerging standards for robust evidence-based policy concerning young people's technology use.
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Schlegel, P., M. T. Binet, J. N. Havenhand, C. J. Doyle, and J. E. Williamson. "Ocean acidification impacts on sperm mitochondrial membrane potential bring sperm swimming behaviour near its tipping point." Journal of Experimental Biology 218, no. 7 (April 1, 2015): 1084–90. http://dx.doi.org/10.1242/jeb.114900.
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Ordway, Stephen W., Dawn M. King, David Friend, Christine Noto, Snowlee Phu, Holly Huelskamp, R. Fredrik Inglis, Wendy Olivas, and Sonya Bahar. "Phase transition behaviour in yeast and bacterial populations under stress." Royal Society Open Science 7, no. 7 (July 2020): 192211. http://dx.doi.org/10.1098/rsos.192211.
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Non-equilibrium phase transitions from survival to extinction have recently been observed in computational models of evolutionary dynamics. Dynamical signatures predictive of population collapse have been observed in yeast populations under stress. We experimentally investigate the population response of the budding yeast Saccharomyces cerevisiae to biological stressors (temperature and salt concentration) in order to investigate the system's behaviour in the vicinity of population collapse. While both conditions lead to population decline, the dynamical characteristics of the population response differ significantly depending on the stressor. Under temperature stress, the population undergoes a sharp change with significant fluctuations within a critical temperature range, indicative of a continuous absorbing phase transition. In the case of salt stress, the response is more gradual. A similar range of response is observed with the application of various antibiotics to Escherichia coli , with a variety of patterns of decreased growth in response to antibiotic stress both within and across antibiotic classes and mechanisms of action. These findings have implications for the identification of critical tipping points for populations under environmental stress.
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Ridley, J. K., J. A. Lowe, and H. T. Hewitt. "How reversible is sea ice loss?" Cryosphere 6, no. 1 (February 13, 2012): 193–98. http://dx.doi.org/10.5194/tc-6-193-2012.
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Abstract. It is well accepted that increasing atmospheric CO2 results in global warming, leading to a decline in polar sea ice area. Here, the specific question of whether there is a tipping point in the sea ice cover is investigated. The global climate model HadCM3 is used to map the trajectory of sea ice area under idealised scenarios. The atmospheric CO2 is first ramped up to four times pre-industrial levels (4 × CO2), then ramped down to pre-industrial levels. We also examine the impact of stabilising climate at 4 × CO2 prior to ramping CO2 down to pre-industrial levels. Against global mean temperature, Arctic sea ice area is reversible, while the Antarctic sea ice shows some asymmetric behaviour – its rate of change slower, with falling temperatures, than its rate of change with rising temperatures. However, we show that the asymmetric behaviour is driven by hemispherical differences in temperature change between transient and stabilisation periods. We find no irreversible behaviour in the sea ice cover.
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Parslew, Ben, Girupakaran Sivalingam, and William Crowther. "A dynamics and stability framework for avian jumping take-off." Royal Society Open Science 5, no. 10 (October 2018): 181544. http://dx.doi.org/10.1098/rsos.181544.
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Jumping take-off in birds is an explosive behaviour with the goal of providing a rapid transition from ground to airborne locomotion. An effective jump is predicated on the need to maintain dynamic stability through the acceleration phase. The present study concerns understanding how birds retain control of body attitude and trajectory during take-off. Cursory observation suggests that stability is achieved with relatively little cost. However, analysis of the problem shows that the stability margins during jumping are actually very small and that stability considerations play a significant role in the selection of appropriate jumping kinematics. We use theoretical models to understand stability in prehensile take-off (from a perch) and also in non-prehensile take-off (from the ground). The primary instability is tipping, defined as rotation of the centre of gravity about the ground contact point. Tipping occurs when the centre of pressure falls outside the functional foot. A contribution of the paper is the development of graphical tipping stability margins for both centre of gravity location and acceleration angle. We show that the nose-up angular acceleration extends stability bounds forward and is hence helpful in achieving shallow take-offs. The stability margins are used to interrogate simulated take-offs of real birds using published experimental kinematic data from a guinea fowl (ground take-off) and a diamond dove (perch take-off). For the guinea fowl, the initial part of the jump is stable; however, simulations exhibit a stuttering instability not observed experimentally that is probably due to the absence of compliance in the idealized joints. The diamond dove model confirms that the foot provides an active torque reaction during take-off, extending the range of stable jump angles by around 45°.
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Rocha, Juan C., Caroline Schill, Lina M. Saavedra-Díaz, Rocío del Pilar Moreno, and Jorge Higinio Maldonado. "Cooperation in the face of thresholds, risk, and uncertainty: Experimental evidence in fisher communities from Colombia." PLOS ONE 15, no. 12 (December 28, 2020): e0242363. http://dx.doi.org/10.1371/journal.pone.0242363.
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Cooperation is thought to be a necessary condition to solve collective action dilemmas such as climate change or the sustainable use of common pool resources. Yet, it is poorly understood how situations pervaded by thresholds shape the behaviour of people facing collective dilemmas. Here we provide empirical evidence that resource users facing thresholds maintain on average cooperative behaviours in the sense of maximising their individual earnings while ensuring future group opportunities. A framed field experiment in the form of a dynamic game with 256 Colombian fishers helped us investigate individual behavioural responses to the existence of thresholds, risk and uncertainty. Thresholds made fishers extract less fish compared to situation without thresholds, but risk had a stronger effect on reducing individual fishing effort. Contrary to previous expectations, cooperation did not break down. If cooperation can be maintained in the face of thresholds, then communicating uncertainty is more policy-relevant than estimating precisely where tipping points lay in social-ecological systems.
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Fankhauser, Rolf. "Influence of systematic errors from tipping bucket rain gauges on recorded rainfall data." Water Science and Technology 37, no. 11 (June 1, 1998): 121–29. http://dx.doi.org/10.2166/wst.1998.0450.
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Tipping bucket rain gauges (TBR) are widely used in urban hydrology. The present study investigated the uncertainties in recorded rainfall intensity induced by the following properties of the TBR: depth resolution i.e. the bucket volume, calibration parameters, wetting and evaporation losses and the method of data recording (time between tips or tips per minute). The errors were analysed by means of a TBR simulator i.e. a simulation program that models the behaviour of a TBR. Rainfall data disaggregated to 6 seconds from measured 1-min data and randomly varied were taken as input to the simulator. Different TBR data series were produced by changing the properties of the simulated rain gauge. These data series together with the original rainfall events were used as input to a rainfall-runoff model. Computed overflow volume and peak discharge from a combined sewer overflow (CSO) weir were compared. Errors due to depth resolution (i.e. the bucket size) proved to be small. Therefore TBRs with a depth resolution up to 0.254 mm can be used in urban hydrology without inducing significant errors. Wetting and evaporation losses caused small errors. The method of data recording had also little influence. For larger bucket volumes variable time step recording induced smaller errors than tips per minute recording.
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Thompson, J. Michael T., and Jan Sieber. "Climate predictions: the influence of nonlinearity and randomness." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 370, no. 1962 (March 13, 2012): 1007–11. http://dx.doi.org/10.1098/rsta.2011.0423.
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The current threat of global warming and the public demand for confident projections of climate change pose the ultimate challenge to science: predicting the future behaviour of a system of such overwhelming complexity as the Earth's climate. This Theme Issue addresses two practical problems that make even prediction of the statistical properties of the climate, when treated as the attractor of a chaotic system (the weather), so challenging. The first is that even for the most detailed models, these statistical properties of the attractor show systematic biases. The second is that the attractor may undergo sudden large-scale changes on a time scale that is fast compared with the gradual change of the forcing (the so-called climate tipping).
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Foo, Jerome Clifford, Hamid Reza Noori, Ikuhiro Yamaguchi, Valentina Vengeliene, Alejandro Cosa-Linan, Toru Nakamura, Kenji Morita, Rainer Spanagel, and Yoshiharu Yamamoto. "Dynamical state transitions into addictive behaviour and their early-warning signals." Proceedings of the Royal Society B: Biological Sciences 284, no. 1860 (August 2, 2017): 20170882. http://dx.doi.org/10.1098/rspb.2017.0882.
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The theory of critical transitions in complex systems (ecosystems, climate, etc.), and especially its ability to predict abrupt changes by early-warning signals based on analysis of fluctuations close to tipping points, is seen as a promising avenue to study disease dynamics. However, the biomedical field still lacks a clear demonstration of this concept. Here, we used a well-established animal model in which initial alcohol exposure followed by deprivation and subsequent reintroduction of alcohol induces excessive alcohol drinking as an example of disease onset. Intensive longitudinal data (ILD) of rat drinking behaviour and locomotor activity were acquired by a fully automated drinkometer device over 14 weeks. Dynamical characteristics of ILD were extracted using a multi-scale computational approach. Our analysis shows a transition into addictive behaviour preceded by early-warning signals such as instability of drinking patterns and locomotor circadian rhythms, and a resultant increase in low frequency, ultradian rhythms during the first week of deprivation. We find evidence that during prolonged deprivation, a critical transition takes place pushing the system to excessive alcohol consumption. This study provides an adaptable framework for processing ILD from clinical studies and for examining disease dynamics and early-warning signals in the biomedical field.
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Green, Andy J. "Comparative feeding behaviour and niche organization in a Mediterranean duck community." Canadian Journal of Zoology 76, no. 3 (March 1, 1998): 500–507. http://dx.doi.org/10.1139/z97-221.
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Feeding behaviour of the Marbled Teal, Marmaronetta angustirostris, Mallard, Anas platyrhynchos, Garganey, Anas querquedula, and Ferruginous Duck, Aythya nyroca, in the Göksu Delta, Turkey, was compared from 10 July to 6 August 1995. Almost all individuals observed were postbreeding adults and juveniles. Marbled Teal fed closest to the surface (mean depth within the water column 8.4 cm), chiefly by bill dipping (66%) and gleaning (14%). Garganey fed at a mean depth of 9.1 cm, mainly by bill dipping (57%) and neck dipping (35%). Mallards fed at greater depths (mean 31.8 cm), mainly by upending (tipping 46%) and neck dipping (41%). Ferruginous Ducks fed at the greatest depths (mean 38.4 cm), chiefly by diving (76%). Marbled Teal moved most frequently between feeding events and Mallards moved least frequently. As in previous studies of dabbling ducks, the largest species (Mallard) upended more and fed deeper in the water column. However, Mallards used shallower microhabitats than smaller dabbling ducks. Dabbling and diving duck guilds were not discernible in either horizontal (feeding habitat) or vertical (feeding behaviour) niche dimensions, and the Mallard and Ferruginous Duck were related in both dimensions. Niche overlaps between species pairs along the two dimensions were negatively correlated (r = -0.71, P = 0.12), supporting niche complementarity.
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Johnston, R. J., and C. J. Pattie. "Is the Seesaw Tipping Back? The End of Thatcherism and Changing Voting Patterns in Great Britain 1979–92." Environment and Planning A: Economy and Space 24, no. 10 (October 1992): 1491–505. http://dx.doi.org/10.1068/a241491.
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Accounts of British voting behaviour in the 1980s stressed the development of growing spatial divides within the country, especially a north-south divide which reflected economic success in the increasingly Conservative-dominated south and depression in the Labour-supporting north. A new geography of recession was emerging in the early 1990s, however, and the first general election since (in April 1992) suggests that the period of divergence has ended, to be replaced by convergence in the electoral geography of Britain though at spatially varying rates and at a pace insufficient to close the political divides entirely and lead to the government's demise.
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Remesan, Renji, Sazeda Begam, and Ian P. Holman. "Effect of baseline snowpack assumptions in the HySIM model in predicting future hydrological behaviour of a Himalayan catchment." Hydrology Research 50, no. 2 (November 23, 2018): 691–708. http://dx.doi.org/10.2166/nh.2018.069.
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Abstract Glaciers and snowpacks influence streamflow by altering the volume and timing of discharge. Without reliable data on baseline snow and ice volumes, properties and behaviour, initializing hydrological models for climate impact assessment is challenging. Two contrasting HySIM model builds were calibrated and validated against observed discharge data (2000–2008) assuming that snowmelt of the baseline permanent snowpack reserves in the high-elevation sub-catchment are either constrained (snowmelt is limited to the seasonal snow accumulation) or unconstrained (snowmelt is only energy-limited). We then applied both models within a scenario-neutral framework to develop impact response surface of hydrological response to future changes in annual temperature and precipitation. Both models had similar baseline model performance (NSE of 0.69–0.70 in calibration and 0.64–0.66 in validation), but the impact response surfaces differ in the magnitude and (for some combinations) direction of model response to climate change at low (Q10) and high (Q90) daily flows. The implications of historical data inadequacies in snowpack characterization for assessing the impacts of climate change and the associated timing of hydrological tipping points are discussed.
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Hamilton, Charmain D., Christian Lydersen, Rolf A. Ims, and Kit M. Kovacs. "Predictions replaced by facts: a keystone species' behavioural responses to declining arctic sea-ice." Biology Letters 11, no. 11 (November 2015): 20150803. http://dx.doi.org/10.1098/rsbl.2015.0803.
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Since the first documentation of climate-warming induced declines in arctic sea-ice, predictions have been made regarding the expected negative consequences for endemic marine mammals. But, several decades later, little hard evidence exists regarding the responses of these animals to the ongoing environmental changes. Herein, we report the first empirical evidence of a dramatic shift in movement patterns and foraging behaviour of the arctic endemic ringed seal ( Pusa hispida ), before and after a major collapse in sea-ice in Svalbard, Norway. Among other changes to the ice-regime, this collapse shifted the summer position of the marginal ice zone from over the continental shelf, northward to the deep Arctic Ocean Basin. Following this change, which is thought to be a ‘tipping point’, subadult ringed seals swam greater distances, showed less area-restricted search behaviour, dived for longer periods, exhibited shorter surface intervals, rested less on sea-ice and did less diving directly beneath the ice during post-moulting foraging excursions. In combination, these behavioural changes suggest increased foraging effort and thus also likely increases in the energetic costs of finding food. Continued declines in sea-ice are likely to result in distributional changes, range reductions and population declines in this keystone arctic species.
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Ridley, J. K., J. A. Lowe, and H. T. Hewitt. "How reversible is sea ice loss?" Cryosphere Discussions 5, no. 5 (September 8, 2011): 2349–63. http://dx.doi.org/10.5194/tcd-5-2349-2011.
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Abstract. It is well accepted that increasing atmospheric CO2 results in global warming, leading to a decline in polar sea ice area. Here, the specific question of whether there is a tipping point in the sea ice cover is investigated. The global climate model HadCM3, is used to map the trajectory of sea ice area under idealised scenarios. The atmospheric CO2 is first ramped up to four times pre-industrial levels (4 × CO2) then ramped down back to pre-industrial levels. We also examine the impact of stabilising climate at 4 × CO2 prior to ramping CO2 down to pre-industrial levels. Against global mean temperature Arctic sea ice area has little hysteresis while the Antarctic sea ice shows significant hysteresis – its rate of change slower, with falling temperatures, than its rate of change with rising temperatures. However, we show that the driver of the hysteresis is the hemispherical differences in temperature change between transient and stabilisation periods. We find no irreversible behaviour in the sea ice cover.
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van den Hoff, John, Clive R. McMahon, and Iain Field. "Tipping back the balance: recolonization of the Macquarie Island isthmus by king penguins (Aptenodytes patagonicus) following extermination for human gain." Antarctic Science 21, no. 3 (March 10, 2009): 237–41. http://dx.doi.org/10.1017/s0954102009001898.
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AbstractDuring the late 19th and early 20th centuries, when blubber oil fuelled house lamps, the king penguin population at Macquarie Island was reduced from two very large (perhaps hundreds of thousands of birds) colonies to about 3000 birds. One colony, located on the isthmus when the island was discovered in 1810, was extinct by 1894 and it took about 100 years for king penguins to re-establish a viable breeding population there. Here we document this recovery. The first eggs laid at Gadget Gully on the isthmus were recorded in late February 1995 but in subsequent years egg laying took place earlier between November and February (this temporal discontinuity is a consequence of king penguin breeding behaviour). The first chick was hatched in April 1995 but the first fledging was not raised until the following breeding season in October 1996. The colony increased on average 66% per annum in the five years between 1995 and 2000. King penguins appear resilient to catastrophic population reductions, and as the island's population increases, it is likely that other previously abandoned breeding sites will be reoccupied.
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Wright, John, Andrew C. Hayward, Jane West, Kate E. Pickett, Rosie M. McEachan, Mark Mon-Williams, Nicola Christie, et al. "ActEarly: a City Collaboratory approach to early promotion of good health and wellbeing." Wellcome Open Research 4 (October 14, 2019): 156. http://dx.doi.org/10.12688/wellcomeopenres.15443.1.
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Economic, physical, built, cultural, learning, social and service environments have a profound effect on lifelong health. However, policy thinking about health research is dominated by the ‘biomedical model’ which promotes medicalisation and an emphasis on diagnosis and treatment at the expense of prevention. Prevention research has tended to focus on ‘downstream’ interventions that rely on individual behaviour change, frequently increasing inequalities. Preventive strategies often focus on isolated leverage points and are scattered across different settings. This paper describes a major new prevention research programme that aims to create City Collaboratory testbeds to support the identification, implementation and evaluation of upstream interventions within a whole system city setting. Prevention of physical and mental ill-health will come from the cumulative effect of multiple system-wide interventions. Rather than scatter these interventions across many settings and evaluate single outcomes, we will test their collective impact across multiple outcomes with the goal of achieving a tipping point for better health. Our focus is on early life (ActEarly) in recognition of childhood and adolescence being such critical periods for influencing lifelong health and wellbeing.
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Zehe, Erwin, Ralf Loritz, Conrad Jackisch, Martijn Westhoff, Axel Kleidon, Theresa Blume, Sibylle K. Hassler, and Hubert H. Savenije. "Energy states of soil water – a thermodynamic perspective on soil water dynamics and storage-controlled streamflow generation in different landscapes." Hydrology and Earth System Sciences 23, no. 2 (February 18, 2019): 971–87. http://dx.doi.org/10.5194/hess-23-971-2019.
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Abstract. The present study confirms that a thermodynamic perspective on soil water is well suited to distinguishing the typical interplay of gravity and capillarity controls on soil water dynamics in different landscapes. To this end, we express the driving matric and gravity potentials by their energetic counterparts and characterize soil water by its free energy state. The latter is the key to defining a new system characteristic determining the possible range of energy states of soil water, reflecting the joint influences of soil physical properties and height over nearest drainage (HAND) in a stratified manner. As this characteristic defines the possible range of energy states of soil water in the root zone, it also allows an instructive comparison of top soil water dynamics observed in two distinctly different landscapes. This is because the local thermodynamic equilibrium at a given HAND and the related equilibrium storage allow a subdivision of the possible free energy states into two different regimes. Wetting of the soil in local equilibrium implies that free energy of soil water becomes positive, which in turn implies that the soil is in a state of storage excess, while further drying of the soil leads to a negative free energy and a state of storage deficit. We show that during 1 hydrological year the energy states of soil water visit distinctly different parts of their respective energy state spaces. The two study areas compared here exhibit furthermore a threshold-like relation between the observed free energy of soil water in the riparian zone and observed streamflow, while the tipping points coincide with the local equilibrium state of zero free energy. We found that the emergence of a potential energy excess/storage excess in the riparian zone coincides with the onset of storage-controlled direct streamflow generation. While such threshold behaviour is not unusual, it is remarkable that the tipping point is consistent with the underlying theoretical basis.
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Riedel, B., T. Pados, K. Pretterebner, L. Schiemer, A. Steckbauer, A. Haselmair, M. Zuschin, and M. Stachowitsch. "Effect of hypoxia and anoxia on invertebrate behaviour: ecological perspectives from species to community level." Biogeosciences 11, no. 6 (March 21, 2014): 1491–518. http://dx.doi.org/10.5194/bg-11-1491-2014.
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Abstract. Coastal hypoxia and anoxia have become a global key stressor to marine ecosystems, with almost 500 dead zones recorded worldwide. By triggering cascading effects from the individual organism to the community- and ecosystem level, oxygen depletions threaten marine biodiversity and can alter ecosystem structure and function. By integrating both physiological function and ecological processes, animal behaviour is ideal for assessing the stress state of benthic macrofauna to low dissolved oxygen. The initial response of organisms can serve as an early warning signal, while the successive behavioural reactions of key species indicate hypoxia levels and help assess community degradation. Here we document the behavioural responses of a representative spectrum of benthic macrofauna in the natural setting in the Northern Adriatic Sea (Mediterranean). We experimentally induced small-scale anoxia with a benthic chamber in 24 m depth to overcome the difficulties in predicting the onset of hypoxia, which often hinders full documentation in the field. The behavioural reactions were documented with a time-lapse camera. Oxygen depletion elicited significant and repeatable changes in general (visibility, locomotion, body movement and posture, location) and species-specific reactions in virtually all organisms (302 individuals from 32 species and 2 species groups). Most atypical (stress) behaviours were associated with specific oxygen thresholds: arm-tipping in the ophiuroid Ophiothrix quinquemaculata, for example, with the onset of mild hypoxia (< 2 mL O2 L−1), the emergence of polychaetes on the sediment surface with moderate hypoxia (< 1 mL O2 L−1), the emergence of the infaunal sea urchin Schizaster canaliferus on the sediment with severe hypoxia (< 0.5 mL O2 L−1) and heavy body rotations in sea anemones with anoxia. Other species changed their activity patterns, for example the circadian rhythm in the hermit crab Paguristes eremita or the bioherm-associated crab Pisidia longimana. Intra- and interspecific reactions were weakened or changed: decapods ceased defensive and territorial behaviour, and predator–prey interactions and relationships shifted. This nuanced scale of resolution is a useful tool to interpret present benthic community status (behaviour) and past mortalities (community composition, e.g. survival of tolerant species). This information on the sensitivity (onset of stress response), tolerance (mortality, survival), and characteristics (i.e. life habit, functional role) of key species also helps predict potential future changes in benthic structure and ecosystem functioning. This integrated approach can transport complex ecological processes to the public and decision-makers and help define specific monitoring, assessment and conservation plans.
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Riedel, B., T. Pados, K. Pretterebner, L. Schiemer, A. Steckbauer, A. Haselmair, M. Zuschin, and M. Stachowitsch. "Effect of hypoxia and anoxia on invertebrate behaviour: ecological perspectives from species to community level." Biogeosciences Discussions 10, no. 8 (August 27, 2013): 14333–438. http://dx.doi.org/10.5194/bgd-10-14333-2013.
Full textAbstract:
Abstract. Coastal hypoxia and anoxia have become a global key stressor to marine ecosystems, with almost 500 dead zones recorded wordwide. By triggering cascading effects from the individual organism to the community and ecosystem-level, oxygen depletions threat marine biodiversity and can alter ecosystem structure and function. By integrating both physiological function and ecological processes, animal behaviour is ideal for assessing the stress state of benthic macrofauna to low dissolved oxygen. The initial response of organisms can serve as an early-warning signal, while the successive behavioural reactions of key species indicate hypoxia levels and help assess community degradation. Here we document the behavioural responses of a representative spectrum of benthic macrofauna in the natural setting in the Northern Adriatic Sea, Mediterranean. We experimentally induced small-scale anoxia with a benthic chamber in 24 m depth to overcome the difficulties in predicting the onset of hypoxia, which often hinders full documentation in the field. The behavioural reactions were documented with a time-lapse camera. Oxygen depletion elicited significant and repeatable changes in general (visibility, locomotion, body movement and posture, location) and species-specific reactions in virtually all organisms (302 individuals from 32 species and 2 species groups). Most atypical (stress) behaviours were associated with specific oxygen thresholds: arm-tipping in the ophiuroid Ophiothrix quinquemaculata, for example, with the onset of mild hypoxia (< 2 mL O2 L−1), the emergence of polychates on the sediment surface with moderate hypoxia (< 1 mL O2 L−1), the emergence of the infaunal sea urchin Schizaster canaliferus on the sediment with severe hypoxia (< 0.5 mL O2 L−1) and heavy body rotations in sea anemones with anoxia. Other species changed their activity patterns, i.e. circadian rhythm in the hermit crab Paguristes eremita or the bioherm-associated crab Pisidia longimana. Intra- and interspecific reactions were weakened or changed: decapods ceased defensive and territorial behaviour, and predator-prey interactions and relationships shifted. This nuanced scale of resolution is a useful tool to interpret present benthic community status (behaviour) and past mortalities (community composition, e.g. survival of tolerant species). This information on the sensitivity (onset of stress response), tolerance (mortality, survival), and characteristics (i.e. life habit, functional role) of key species also helps predict potential future changes in benthic structure and ecosystem functioning. This integrated approach can transport complex ecological processes to the public and decision-makers and help define specific monitoring, assessment and conservation plans.
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Louchet, François. "A Brief Theory of Epidemic Kinetics." Biology 9, no. 6 (June 22, 2020): 134. http://dx.doi.org/10.3390/biology9060134.
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In the context of the COVID-19 epidemic, and on the basis of the Theory of Dynamical Systems, we propose a simple theoretical approach for the expansion of contagious diseases, with a particular focus on viral respiratory tracts. The infection develops through contacts between contagious and exposed people, with a rate proportional to the number of contagious and of non-immune individuals, to contact duration and turnover, inversely proportional to the efficiency of protection measures, and balanced by the average individual recovery response. The obvious initial exponential increase is readily hindered by the growing recovery rate, and also by the size reduction of the exposed population. The system converges towards a stable attractor whose value is expressed in terms of the “reproductive rate” R0, depending on contamination and recovery factors. Various properties of the attractor are examined, and particularly its relations with R0. Decreasing this ratio below a critical value leads to a tipping threshold beyond which the epidemic is over. By contrast, significant values of the above ratio may bring the system through a bifurcating hierarchy of stable cycles up to a chaotic behaviour.
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Thomas, Z. A., F. Kwasniok, C. A. Boulton, P. M. Cox, R. T. Jones, T. M. Lenton, and C. S. M. Turney. "Early warnings and missed alarms for abrupt monsoon transitions." Climate of the Past Discussions 11, no. 2 (April 13, 2015): 1313–41. http://dx.doi.org/10.5194/cpd-11-1313-2015.
Full textAbstract:
Abstract. Palaeo-records from China (Cheng et al., 2009; Wang et al., 2008, 2001) demonstrate the East Asian Summer Monsoon (EASM) is dominated by abrupt and large magnitude monsoon shifts on millennial timescales, switching between periods of high and weak monsoon rains. It has been hypothesised that over these timescales, the EASM exhibits two stable states with bifurcation-type tipping points between them (Schewe et al., 2012). Here we test this hypothesis by looking for early warning signals of past bifurcations in speleothem records from Sanbao Cave and Hulu Cave, China (Wang et al., 2008, 2001), spanning the penultimate glacial cycle, and in multiple model simulations derived from the data. We find hysteresis behaviour in our model simulations with transitions directly forced by solar insolation. We detect critical slowing down prior to an abrupt monsoon shift during the penultimate deglaciation consistent with long-term orbital forcing. However, such signals are only detectable when the change in system stability is sufficiently slow to be detected by the sampling resolution of the dataset, raising the possibility that the alarm was missed and a similar forcing drove earlier EASM shifts.
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Lanza, L. G., E. Vuerich, and I. Gnecco. "Analysis of highly accurate rain intensity measurements from a field test site." Advances in Geosciences 25 (March 9, 2010): 37–44. http://dx.doi.org/10.5194/adgeo-25-37-2010.
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Abstract. In the course of the recent WMO international instrument intercomparison in the field and the associated specific laboratory tests, highly accurate rainfall intensity measurements have been collected and made available for scientific investigation. The resulting high quality data set (contemporary one-minute rainfall intensity data from 26 gauges based on various measuring principles) constitutes an important resource to provide insights into the expected behaviour of rain intensity gauges in operational conditions and further useful information for National Meteorological Services and other users. A few aspects of the analysis of one-minute resolution rain intensity measurements are discussed in this paper, focusing on the observed deviations from a calculated reference intensity based on four pit gauges. Results from both catching and non-catching type gauges are discussed in relation with suitable tolerance limits obtained as a combination of the estimated uncertainty of the reference intensity and the WMO accuracy limits for rainfall intensity measurements. It is shown that suitably post-processed weighing gauges and tipping-bucket rain gauges had acceptable performance, while none of the non-catching rain gauges agreed well with the reference.
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Eitzinger, B., and G. Ederer. "The Use of Nonlinear Constitutive Equations to Evaluate Draw Resistance and Filter Ventilation." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 19, no. 4 (January 1, 2001): 177–88. http://dx.doi.org/10.2478/cttr-2013-0706.
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AbstractThis study investigates by nonlinear constitutive equations the influence of tipping paper, cigarette paper, filter, and tobacco rod on the degree of filter ventilation and draw resistance. Starting from the laws of conservation, the path to the theory of fluid dynamics in porous media and Darcy's law is reviewed and, as an extension to Darcy's law, two different nonlinear pressure drop-flow relations are proposed. It is proven that these relations are valid constitutive equations and the partial differential equations for the stationary flow in an unlit cigarette covering anisotropic, inhomogeneous and nonlinear behaviour are derived. From these equations a system of ordinary differential equations for the one-dimensional flow in the cigarette is derived by averaging pressure and velocity over the cross section of the cigarette. By further integration, the concept of an electrical analog is reached and discussed in the light of nonlinear pressure drop-flow relations. By numerical calculations based on the system of ordinary differential equations, it is shown that the influence of nonlinearities cannot be neglected because variations in the degree of filter ventilation can reach up to 20% of its nominal value.
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Alkhayuon, Hassan, Peter Ashwin, Laura C. Jackson, Courtney Quinn, and Richard A. Wood. "Basin bifurcations, oscillatory instability and rate-induced thresholds for Atlantic meridional overturning circulation in a global oceanic box model." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, no. 2225 (May 2019): 20190051. http://dx.doi.org/10.1098/rspa.2019.0051.
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The Atlantic meridional overturning circulation (AMOC) transports substantial amounts of heat into the North Atlantic sector, and hence is of very high importance in regional climate projections. The AMOC has been observed to show multi-stability across a range of models of different complexity. The simplest models find a bifurcation associated with the AMOC ‘on’ state losing stability that is a saddle node. Here, we study a physically derived global oceanic model of Wood et al. with five boxes, that is calibrated to runs of the FAMOUS coupled atmosphere-ocean general circulation model. We find the loss of stability of the ‘on’ state is due to a subcritical Hopf for parameters from both pre-industrial and doubled CO 2 atmospheres. This loss of stability via subcritical Hopf bifurcation has important consequences for the behaviour of the basin of attraction close to bifurcation. We consider various time-dependent profiles of freshwater forcing to the system, and find that rate-induced thresholds for tipping can appear, even for perturbations that do not cross the bifurcation. Understanding how such state transitions occur is important in determining allowable safe climate change mitigation pathways to avoid collapse of the AMOC.
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Baker, RR, M. Dixon, and CA Hill. "The Incidence and Consequences of Filter Vent Blocking Amongst British Smokers." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 18, no. 2 (August 1, 1998): 71–83. http://dx.doi.org/10.2478/cttr-2013-0672.
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AbstractVent blocking, the intentional or unintentional covering of the filter ventilation holes during smoking, is an aspect of smoking behaviour which could influence mainstream smoke yields. This study was designed to determine if, and to what extent, vent blocking by smokers’ lips occurs. Three groups of British smokers were asked to smoke their own brand of cigarette which was either an unventilated filter brand, or one of two brands containing different levels of filter ventilation. 300 Smokers were used in each group and the filter butts were collected. Approximately 10 filter butts per smoker were collected. The filter tipping papers were removed and treated with a ninhydrin solution. This stained the saliva imprint on the paper so that the mouth insertion depth of the cigarette could be measured. In addition, levels of retained nicotine on the filters were also determined. This, together with the known filtration efficiencies of the filter, enabled an estimate to be made of the mainstream nicotine yield of the cigarette during the smoking. The results indicate that British smokers have an average insertion depth of about 8.5 mm. 85 % of the ventilated filters examined showed no vent coverage by the smokers’ lips, 15 % showed some coverage. Based on the techniques used in the present study it appears that the presence or absence of filter ventilation zone coverage by lips is not reflected in the estimated nicotine yields to smokers. It is likely that other smoker behaviour factors have a more substantial role in determining nicotine yields within each cigarette delivery category.
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Clark, Ian, Sebastian Kaempf, Christian Reus-Smit, and Emily Tannock. "Crisis in the laws of war? Beyond compliance and effectiveness." European Journal of International Relations 24, no. 2 (June 28, 2017): 319–43. http://dx.doi.org/10.1177/1354066117714528.
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How can we tell what state the laws of war are in today, and whether they face exceptional pressures? Standard accounts of the condition of this body of law focus on problems of compliance and effectiveness. In particular, there is a dominant international legal diagnosis that most non-compliance is accounted for by the prevalence of non-state belligerents in irregular or asymmetric conflicts. We propose that any such diagnosis is partial at best. A focus on compliance and effectiveness tells us nothing about the reasons for actor behaviour, or about its impact on the regime. We advance a different conceptual framework, exploring the complex connections between compliance, effectiveness and legitimacy. We propose an alternative diagnostic model that places legitimacy at the heart of the analysis, treating it as causal, not simply symptomatic. This highlights when violations result in legitimacy costs for the individual actor, as opposed to reaching a tipping point when violations cumulatively impose legitimacy costs on the regime itself. We argue for the need to move beyond discussions framed by compliance and effectiveness, and towards the forms, reasons and reception of non-compliant behaviour, as this provides a truly social measure of the state of the law. In order to illustrate this, we examine three distinct types of challengers — Islamic State of Iraq and the Levant, the US and Russia — and present them as, respectively, revisionist, rejectionist and denialist threats to the regime. Unusually, the laws of war today face challenges on all three fronts simultaneously.
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Studer, Bettina, Alicja Timm, Barbara J. Sahakian, Tobias Kalenscher, and Stefan Knecht. "A decision-neuroscientific intervention to improve cognitive recovery after stroke." Brain 144, no. 6 (March 20, 2021): 1764–73. http://dx.doi.org/10.1093/brain/awab128.
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Abstract Functional recovery after stroke is dose-dependent on the amount of rehabilitative training. However, rehabilitative training is subject to motivational hurdles. Decision neuroscience formalizes drivers and dampers of behaviour and provides strategies for tipping motivational trade-offs and behaviour change. Here, we used one such strategy, upfront voluntary choice restriction (‘precommitment’), and tested if it can increase the amount of self-directed rehabilitative training in severely impaired stroke patients. In this randomized controlled study, stroke patients with working memory deficits (n = 83) were prescribed daily self-directed gamified cognitive training as an add-on to standard therapy during post-acute inpatient neurorehabilitation. Patients allocated to the precommitment intervention could choose to restrict competing options to self-directed training, specifically the possibility to meet visitors. This upfront choice restriction was opted for by all patients in the intervention group and highly effective. Patients in the precommitment group performed the prescribed self-directed gamified cognitive training twice as often as control group patients who were not offered precommitment [on 50% versus 21% of days, Pcorr = 0.004, d = 0.87, 95% confidence interval (CI95%) = 0.31 to 1.42], and, as a consequence, reached a 3-fold higher total training dose (90.21 versus 33.60 min, Pcorr = 0.004, d = 0.83, CI95% = 0.27 to 1.38). Moreover, add-on self-directed cognitive training was associated with stronger improvements in visuospatial and verbal working memory performance (Pcorr = 0.002, d = 0.72 and Pcorr = 0.036, d = 0.62). Our neuroscientific decision add-on intervention strongly increased the amount of effective cognitive training performed by severely impaired stroke patients. These results warrant a full clinical trial to link decision-based neuroscientific interventions directly with clinical outcome.
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Golledge, Nicholas R., Zoë A. Thomas, Richard H. Levy, Edward G. W. Gasson, Timothy R. Naish, Robert M. McKay, Douglas E. Kowalewski, and Christopher J. Fogwill. "Antarctic climate and ice-sheet configuration during the early Pliocene interglacial at 4.23 Ma." Climate of the Past 13, no. 7 (July 27, 2017): 959–75. http://dx.doi.org/10.5194/cp-13-959-2017.
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Abstract. The geometry of Antarctic ice sheets during warm periods of the geological past is difficult to determine from geological evidence, but is important to know because such reconstructions enable a more complete understanding of how the ice-sheet system responds to changes in climate. Here we investigate how Antarctica evolved under orbital and greenhouse gas conditions representative of an interglacial in the early Pliocene at 4.23 Ma, when Southern Hemisphere insolation reached a maximum. Using offline-coupled climate and ice-sheet models, together with a new synthesis of high-latitude palaeoenvironmental proxy data to define a likely climate envelope, we simulate a range of ice-sheet geometries and calculate their likely contribution to sea level. In addition, we use these simulations to investigate the processes by which the West and East Antarctic ice sheets respond to environmental forcings and the timescales over which these behaviours manifest. We conclude that the Antarctic ice sheet contributed 8.6 ± 2.8 m to global sea level at this time, under an atmospheric CO2 concentration identical to present (400 ppm). Warmer-than-present ocean temperatures led to the collapse of West Antarctica over centuries, whereas higher air temperatures initiated surface melting in parts of East Antarctica that over one to two millennia led to lowering of the ice-sheet surface, flotation of grounded margins in some areas, and retreat of the ice sheet into the Wilkes Subglacial Basin. The results show that regional variations in climate, ice-sheet geometry, and topography produce long-term sea-level contributions that are non-linear with respect to the applied forcings, and which under certain conditions exhibit threshold behaviour associated with behavioural tipping points.
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Thomas, Z. A., F. Kwasniok, C. A. Boulton, P. M. Cox, R. T. Jones, T. M. Lenton, and C. S. M. Turney. "Early warnings and missed alarms for abrupt monsoon transitions." Climate of the Past 11, no. 12 (December 8, 2015): 1621–33. http://dx.doi.org/10.5194/cp-11-1621-2015.
Full textAbstract:
Abstract. Palaeo-records from China demonstrate that the East Asian Summer Monsoon (EASM) is dominated by abrupt and large magnitude monsoon shifts on millennial timescales, switching between periods of high and weak monsoon rains. It has been hypothesized that over these timescales, the EASM exhibits two stable states with bifurcation-type tipping points between them. Here we test this hypothesis by looking for early warning signals of past bifurcations in speleothem δ18O records from Sanbao Cave and Hulu Cave, China, spanning the penultimate glacial cycle. We find that although there are increases in both autocorrelation and variance preceding some of the monsoon transitions during this period, it is only immediately prior to the abrupt monsoon shift at the penultimate deglaciation (Termination II) that statistically significant increases are detected. To supplement our data analysis, we produce and analyse multiple model simulations that we derive from these data. We find hysteresis behaviour in our model simulations with transitions directly forced by solar insolation. However, signals of critical slowing down, which occur on the approach to a bifurcation, are only detectable in the model simulations when the change in system stability is sufficiently slow to be detected by the sampling resolution of the data set. This raises the possibility that the early warning "alarms" were missed in the speleothem data over the period 224–150 kyr and it was only at the monsoon termination that the change in the system stability was sufficiently slow to detect early warning signals.
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Lynn, Michael, and Zachary W. Brewster. "The Tipping Behavior and Motives of US Travelers Abroad: Affected by Host Nations’ Tipping Norms?" Journal of Travel Research 59, no. 6 (October 4, 2019): 993–1007. http://dx.doi.org/10.1177/0047287519875820.
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Despite the size and interdisciplinary scope of the extant literature on domestic tipping behaviors, little research has been done on the tipping behaviors of tourists when traveling abroad. In response, this study presents results from a hypothetical scenario experiment indicating that tipping by US tourists follows the tipping norms of the visited nations and increases with future service, reciprocity, and altruism motives for tipping as well as with favorable attitudes toward the custom. National tipping norms did not moderate the effects of tipping motives but did moderate the effects of respondents’ attitude toward tipping. Specifically, the likelihood that tourists would tip increased with their positivity toward the practice, but significantly less so when tipping was customary and expected in the host country. Discussion focuses on the implications of these findings for the generalizability of previous tipping research and strategies for increasing tipping by foreign tourists.
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Davis, Stephen F., Brian Schrader, Teri R. Richardson, Jason P. Kring, and Jamie C. Kieffer. "Restaurant Servers Influence Tipping Behavior." Psychological Reports 83, no. 1 (August 1998): 223–26. http://dx.doi.org/10.2466/pr0.1998.83.1.223.
Full textAbstract:
12 waiters and waitresses from a small Midwestern town and 16 waiters and waitresses from a large urban area participated in an experiment to assess whether larger tips were given when they stood erect or squatted when taking orders. Using an A-B-A-B research design, waiters and waitresses alternately stood and squatted for a 4-wk. period while taking orders at lunch and dinner. The research was conducted in moderately priced, family-style restaurants. Analysis indicated that significantly higher tips were given (a) at dinner than lunch, (b) in the urban area, (c) to female servers, and (d) when the server squatted.
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DAVIS, STEPHEN F. "RESTAURANT SERVERS INFLUENCE TIPPING BEHAVIOR." Psychological Reports 83, no. 5 (1998): 223. http://dx.doi.org/10.2466/pr0.83.5.223-226.
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Ge, Qi. "Sports sentiment and tipping behavior." Journal of Economic Behavior & Organization 145 (January 2018): 95–113. http://dx.doi.org/10.1016/j.jebo.2017.10.016.
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