What is broken? Expected lifetime, perception of brokenness and attitude towards maintenance and repair

This paper addresses the discrepancy between the expected and actual lifetimes of vacuum cleaners considering perceived ‘brokenness’ as a driver for replacement. Among electrical products, vacuum cleaners have a high rate of domestic ownership in the UK. They also embody large quantities of greenhouse gases which could be reduced by increasing their longevity and resource efficiency (Schreiber et al., 2012). A focus on energy efficiency has only shown limited or even negative results, therefore to meet recent European Union regulations on durability requirements a focus on product longevity is needed. Around one half of new vacuum cleaner purchasers replace one less than 5 years old, below the expected lifespan, with perceived breakage, poor performance and unreliability as the major reasons for replacement. Their relative simplicity could allow vacuum cleaners to last for significantly longer. The nature of the common causes of failure is known, including stretched cords or blockages, and WRAP has developed guidelines for product improvements. However, many working or repairable machines are disposed of because they are perceived to be ‘irremediably’ broken

The joy of vacuuming? How the user experience affects vacuum cleaner longevity

An apparent reduction in the average lifetime of vacuum cleaners is explored in this paper in relation to their perceived usability and increasingly frequent product replacement. Motivations for product disposal combine perceived and real product failure with a perceived or real improved product offer. From an historical perspective, vacuum cleaners typify this pattern, continually offering a ‘cheaper and improved’ product. Vacuum cleaner manufacturers reinvigorate the sense of satisfaction and revulsion associated with extracting dirt from our homes through new performance focused product development. For example, increased motor power, filtration, bag-less machines and clear bin compartments have all acted as sales drivers, whilst cost effective materials and offshore and more efficient manufacturing have reduced purchase prices. The latter, cost-driven, processes can create machines that are more likely to be functionally and aesthetically damaged in use, reinforcing the trend for faster replacement. The market appears likely to continue to focus on improved user experience, with growth in market share for lighter weight cordless battery powered machines posing the risk of an increased environmental burden. Drawing from qualitative and quantitative research undertaken for a study for Defra, we explore the user’s relationship to the product, investigating the frustrations and joys of vacuum cleaner use and ownership. The findings illustrate that the revulsion and attraction of cleaning, as well as the tedium and satisfaction fostered by the product, have direct implications for vacuum cleaner longevity

The relationship between ideas about cleanliness and actions that affect product longevity

As Mary Douglas famously put it, ‘where there is dirt there is system’ (1991 (1966): 35). She was concerned particularly with the cultural systems that determine the ideas about dirt that motivate and constrain people’s actions with material objects. This paper assumes that such motivations and constraints may affect consumers’ willingness to keep or to dispose of their possessions, and therefore have an impact on product longevity. It reports on ongoing empirical research using product analysis, ethnographic interviews, a questionnaire and student design work into the possibility of increasing the longevity of vacuum cleaners by design interventions. Because its object of study is a cleaning product used in everyday cleaning practices, the research naturally connects with Douglas’ ideas as well as more recent work such as Dant 2003 that focuses on how people deal practically with the materiality of dirt, not determined by cultural categories. This paper builds on Vaussard et al.’s (2014) classification of individuals by their degree of concern for keeping their house clean, into ‘Spartan’, ‘Minimalistic’, ‘Caring’ and ‘Committed’ cleaners and their implications for vacuum cleaner replacement. Introducing a short history of concern about dirt since germ theory, it considers whether the desire for a more up to date/efficient/powerful/good looking/clean/shiny machine may accelerate replacement. It finally considers whether a design that ‘ages gracefully’ might have a longer life-span, either as a personal possession or as part of a service system

Minimal Brownian Ratchet: An Exactly Solvable Model

We develop an exactly-solvable three-state discrete-time minimal Brownian ratchet (MBR), where the transition probabilities between states are asymmetric. By solving the master equations we obtain the steady-state probabilities. Generally the steady-state solution does not display detailed balance, giving rise to an induced directional motion in the MBR. For a reduced two-dimensional parameter space we find the null-curve on which the net current vanishes and detailed balance holds. A system on this curve is said to be balanced. On the null-curve, an additional source of external random noise is introduced to show that a directional motion can be induced under the zero overall driving force. We also indicate the off-balance behavior with biased random noise.Comment: 4 pages, 4 figures, RevTex source, General solution added. To be appeared in Phys. Rev. Let

New paradoxical games based on Brownian ratchets

Based on Brownian ratchets, a counter-intuitive phenomenon has recently emerged -- namely, that two losing games can yield, when combined, a paradoxical tendency to win. A restriction of this phenomenon is that the rules depend on the current capital of the player. Here we present new games where all the rules depend only on the history of the game and not on the capital. This new history-dependent structure significantly increases the parameter space for which the effect operates.Comment: 4 pages, 3 eps figures, revte

A review of stochastic resonance: Circuits and measurement

Copyright © 2002 IEEENoise in dynamical systems is usually considered a nuisance. However, in certain nonlinear systems, including electronic circuits and biological sensory systems, the presence of noise can enhance the detection of weak signals. The phenomenon is termed stochastic resonance and is of great interest for electronic instrumentation. We review and investigate the stochastic resonance of several bistable circuits. A new type of S characteristic circuit is demonstrated using simple nonlinear elements with an operational amplifier. Using this circuit, the effects on stochastic resonance were determined as the slope of the S shaped characteristic curve was varied.Gregory P. Harmer, Bruce R. Davis and Derek Abbot

Mutation of Arabidopsis SPLICEOSOMAL TIMEKEEPER LOCUS1 Causes Circadian Clock Defects

The circadian clock plays a crucial role in coordinating plant metabolic and physiological functions with predictable environmental variables, such as dusk and dawn, while also modulating responses to biotic and abiotic challenges. Much of the initial characterization of the circadian system has focused on transcriptional initiation, but it is now apparent that considerable regulation is exerted after this key regulatory step. Transcript processing, protein stability, and cofactor availability have all been reported to influence circadian rhythms in a variety of species. We used a genetic screen to identify a mutation within a putative RNA binding protein (SPLICEOSOMAL TIMEKEEPER LOCUS1 [STIPL1]) that induces a long circadian period phenotype under constant conditions. STIPL1 is a homolog of the spliceosomal proteins TFP11 (Homo sapiens) and Ntr1p (Saccharomyces cerevisiae) involved in spliceosome disassembly. Analysis of general and alternative splicing using a high-resolution RT-PCR system revealed that mutation of this protein causes less efficient splicing of most but not all of the introns analyzed. In particular, the altered accumulation of circadian-associated transcripts may contribute to the observed mutant phenotype. Interestingly, mutation of a close homolog of STIPL1, STIP-LIKE2, does not cause a circadian phenotype, which suggests divergence in function between these family members. Our work highlights the importance of posttranscriptional control within the clock mechanism. © 2012 American Society of Plant Biologists. All rights reserved

Brownian ratchets and Parrondo's games

Parrondo's games present an apparently paradoxical situation where individually losing games can be combined to win. In this article we analyze the case of two coin tossing games. Game B is played with two biased coins and has state-dependent rules based on the player's current capital. Game B can exhibit detailed balance or even negative drift (i.e., loss), depending on the chosen parameters. Game A is played with a single biased coin that produces a loss or negative drift in capital. However, a winning expectation is achieved by randomly mixing A and B. One possible interpretation pictures game A as a source of "noise" that is rectified by game B to produce overall positive drift-as in a Brownian ratchet. Game B has a state-dependent rule that favors a losing coin, but when this state dependence is broken up by the noise introduced by game A, a winning coin is favored. In this article we find the parameter space in which the paradoxical effect occurs and carry out a winning rate analysis. The significance of Parrondo's games is that they are physically motivated and were originally derived by considering a Brownian ratchet-the combination of the games can be therefore considered as a discrete-time Brownian ratchet. We postulate the use of games of this type as a toy model for a number of physical and biological processes and raise a number of open questions for future research. (c) 2001 American Institute of Physics.Gregory P. Harmer, Derek Abbott, Peter G. Taylor, and Juan M. R. Parrond

Reduced up-regulation of gene expression in response to elevated temperatures in the mid-Atlantic population of Calanus finmarchicus

Abstract Climate change is affecting numerous species worldwide, including dominant and important copepods of the genus Calanus. Despite the growing body of studies that examine effects of climate change stressors on Calanus species, comparative intraspecific studies are lacking. Importantly, acclimatization and genetic adaptation can modify the stress response, thus leading to a differential response of separated populations to the same stressor. The molecular and physiological responses of a C. finmarchicus population from the mid-Atlantic, with an in situ temperature of 8.5 °C, were investigated under experimental thermal conditions of 0 °C, 5 °C, 10 °C, 15 °C, and 20 °C for durations of 3 h and 6 days. This experimental set-up mirrored previously published experiments conducted on C. finmarchicus at the northern limit of its distribution allowing a comparison between two populations. The greatest physiological response, assessed as fecal pellet production, was seen after 3 h exposure at 10 °C and 15 °C, and after 6 days exposure at 5 °C, 10 °C and 15 °C. Molecular response was assessed by the change in expression of 5 selected genes: hsp70_2, dnaja1, nap 1l1, rps11, and gdh. Only two out of the five genes (gdh and nap1l1) showed significant up-regulation with increased temperature and duration of exposure. These findings differ from the results obtained in the northern population where all 5 genes were differently expressed. Overall, the results suggest population-specific response to temperature in C. finmarchicus, however determining the source of such variation (genetic adaptation or acclimatization) requires more detailed studies