Domino model

Reason reinvented the Domino Model twenty years later in what he called the Swiss Cheese model, with layers of Swiss cheese substituted for dominos and the layers or dominos labeled as layers of defense that have failed [172,173]. 

The basic Domino Model is inadequate for complex systems and other models were developed (see Safeware [115], chapter 10), but the assumption that there is a single or root cause of an accident unfortunately persists as does the idea of dominos (or layers of Swiss cheese) and chains of failures, each directly causing or leading to the next one in the chain. It also lives on in the emphasis on human error in identifying accident causes. 

Updated Domino Model (Bird Jr, quoted in Heinrich et al., 1980)... 

Heinrich advocated a multidisciplinary approach to safety, focused on engineering, psychology, management, and salesmanship. The emphasis on psychology supported his theory that the majority of accidents were caused primarily by the unsafe acts or behavior of employees— the axiom on which his prevention philosophy was based. This axiom was central to Heinrich s domino model of accident causation, which depicted five dominos lined up in a sequence. As we discussed in Chapter 12 (Figures 12-7 and 12-8), unsafe acts/conditions were placed in the central position, preceded by inherited or acquired personal faults, and followed by an inci-... 

The prototype for the sequential accident model is the Domino model. The Domino model represents simple, linear causahty, as in the case of a set of domino pieces that fall one after the other. According to the logic of this model, the purpose of event analysis is to find the component that failed, by reasoning backwards from the final consequence. This corresponds in all essentials to the principle of the Root Cause Analysis (RCA), which will be described in more detail in the following. Similarly, risk analysis looks for whether something may break, meaning... 

The concept of human error became part of safety lore when Heinrich noted that as improved equipment and methods were introduced, accidents from purely mechanical or physical causes decreased and (hu)man failure became the predominant cause of injury. This assumption became the second of the five dominoes in the famous Domino model, described as fault of person. This is in good agreement with the philosophical and psychological tradition to treat human error as an individual characteristic or a personality trait. A modern example of that is the zero-risk hypothesis of driving, which proposes that drivers aim to keep their subjectively perceived risk at zero level. 

The natural consequence of the causality credo, combined with the Domino model, is the assumption that there is a basic or first cause, which can be found if the systematic search is continued until it can go no further. This is often called the root cause, although definitions differ. In the Domino model, the root cause was the ancestry and social environment, which led to undesirable traits of character. Since this was the fifth domino, it was not possible to continue the analysis any further. Other approaches, particular if they subscribe to some form of abstraction hierarchy, suffer from the same limitation. The type of analysis (which actually is a family of methods) that tries to find the root cause is unsurprisingly called Root Cause Analysis (RCS). 

A description of the three types of accident models can be found in Hollnagel, E. (2004), Barriers and Accident Prevention, Aldershot Ashgate. As already mentioned in the Comments on Chapter 3, the book also provides a detailed analysis and characterisation of various barrier systems. The best known among the many accident models are the Domino model put forward by Heinrich in 1931, and the Swiss cheese model described by Reason, J. (1990), Human Error, Cambridge Cambridge University Press. 

To put it simply the ontology of Safety-1 cannot be sustained. Or rather, Safety-1 thinking is no longer universally applicable. We must keep in mind that even if we limit the focus to traditional safety concerns, this way of thinking was developed almost a century ago. The Domino model was described in a book published in 1931, but the experiences that led to the ideas and theories described in the book were from the preceding decades. The thinking that was relevant for the work environments at the beginning of the twentieth century is unlikely to be relevant today when socio-technical systems are not decomposable, bimodal, or predictable. 

The selectivity of the aldol addition can be rationalized in terms of a Zimmer -man-Traxler transition-state model with TS-2-50 having the lowest energy and leading to dr-values of >95 5 for 2-51 and 2-52 [18]. The chiral copper complex, responsible for the enantioselective 1,4-addition of the dialkyl zinc derivative in the first anionic transformation, seems to have no influence on the aldol addition. To facilitate the ee-determination of the domino Michael/aldol products and to show that 2-51 and 2-52 are l -epimers, the mixture of the two compounds was oxidized to the corresponding diketones 2-53. 

For the domino transition metal-catalyzed synthesis of macrocycles, conditions must be found for two distinct cross-coupling reactions, of which one is inter- and the other intramolecular. For this purpose, Zhu s group [115] has developed a process of a Miyura arylboronic ester formation followed by an intramolecular Suzuki reaction to give model compounds of the biphenomycin structure 6/1-232 containing an endo-aryl-aryl bond. 

The periodic recurrence of cell division suggests that globally the cell cycle functions like an autonomous oscillator. An extended model incorporating the sequential activation of the various cyclin-dependent kinases, followed by their inactivation, shows that even in the absence of control by cell mass, this sequence of biochemical events can operate as a limit cycle oscillator [145]. This supports the union of the two views of the cell cycle as dominoes and clock [146]. Because of the existence of checkpoints, however, the cell cycle stops at the end of certain phases before engaging in the next one. Thus the cell cycle looks more like an oscillator that slows down and makes occasional stops. A metaphor for such behavior is provided by the movement of the round plate on the table in a Chinese restaurant, which would rotate continuously under the movement imparted by the participants, were it not for frequent stops. 

As model studies and radical reactivity control have improved, the so-called cascade (or domino) reactions have emerged as a very powerful method for natural product synthesis, since they offer a unique route to prepare complex backbones from appropriately designed but quite simple precursors. A few selected reactions will be presented here. 

The uncompetitive NMDA receptor antagonist ketamine has been available for clinical use as an anaesthetic for 40 years (Domino et al. 1965). Ketamine is effective in various animal models of hyperalgesia and allodynia and has been reported to have antinociceptive effects in some of these models at doses devoid of obvious side-effects. Others, however, have reported that the effects of ketamine are only seen at doses producing ataxia (see Parsons 2001 for review). Ketamine reportedly inhibits the area of secondary hyperalgesia induced by chemical (Park et al. 1995) or thermal stimuli (Ilkjaer et al. 1996 Warncke et al. 1997) and inhibits temporal siunmation of repeated mechanical (Warncke et al. 1997) and electrical stimuli (Arendtnielsen et al. 1995 Andersen et al. 

Polybrominated Biphenyls. Tlie mechanism by which PBBs enter the blood stream in humans is not known consequently, there are no established methods for reducing absorption. Studies in experimental animals that could identify substances that prevent or delay absorption and that do not represent a toxic risk per se would be valuable. Tliere are no established methods for reducing body burden in humans, but studies in animals and model simulations in humans indicate that reducing body fat markedly increases elimination of PBBs (Domino et al. 1982 Tuey and Matthews 1980). The effect of reduction of body fat (e.g., by dieting and exercising) in PBB-exposed humans has not been fully researched. 

Wall et al.9 administered 1.3 pg/kg of 3H-PCP intravenously to human volunteers and collected blood samples for 72 h. Data from this study suggested a two-compartment pharmacokinetic model with a plasma half-life for PCP of 7 to 16 h. Domino et al.10 further analyzed the data from Wall et al. and developed a more complex three-compartment PK model. The reported half-lives for... 

Delmas C, Maccario M, Croguennec L, Le Cras F, Weill F. Lithium deintercalation in LiFePC>4 nanoparticles via a domino-cascade model. Nature Mater. 2008 7 665-71. 

Domino E, Luby E. 1981. Abnormal mental states induced by phencyclidine as a model of schizophrenia. PCP (Phencyclidine) Historical and Current Perspectives. Domino E, editor. Ann Arbor, Michigan NPP Books. 

Luby ED, Gottlieb JS, Cohen BD, Rosenbaum G, Domino EE 1962. Model psychoses and schizophrenia. Am J Psychiatry 119 61-67. 

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