Tail Off Research Articles

Effects of creative and social activity on the health and well-being of socially isolated older people: outcomes from a multi-method observational study

Depression and social isolation affect one in seven people over 65 and there is increasing recognition that social isolation adversely affects long-term health. Research indicates that interventions, which promote active social contact, which encourage creativity, and which use mentoring, are more likely to positively affect health and well-being. The purpose of this study was to evaluate a complex intervention for addressing social isolation in older people, embodying these principles: The Upstream Healthy Living Centre. Mentors delivered a series of individually-tailored activities, with support tailing off over time. Two hundred and twenty-nine participants were offered the Geriatric Depression Scale, SF12 Health Quality of Life, and Medical Outcomes Social Support scale at baseline, then 6 months and 12 months post intervention. Semi-structured interviews were conducted with 26 participants, five carers and four referring health professionals to provide a deeper understanding of outcomes. Data were available for 172 (75%) participants at baseline, 72 (53% of those eligible) at 6 months and 51 (55%) at 12 months. Baseline scores indicated social isolation and high morbidity for mental and physical health. The intervention was successful in engaging this population (80% of referrals were engaged in some form of activity). At 6 months, there were significant improvements in SF12 mental component, and depression scores, but not in perceived physical health or social support. At 12 months, there were significant improvements in depression and social support and a marginally significant improvement in SF12 physical component (p = 0.06), but the SF12 mental component change was not maintained. The qualitative data showed that the intervention was well-received by participants. The data indicated a wide range of responses (both physical and emotional), including increased alertness, social activity, self-worth, optimism about life, and positive changes in health behaviour. Stronger, 'transformational' changes were reported by some participants. Individual tailoring seemed to be a key mediator of outcomes, as was overcoming barriers relating to transport and venues. Key processes underlying outcomes were the development of a positive group identity, and building of confidence/self-efficacy. The Upstream model provides a practical way of engaging socially isolated elderly people and generating social networks. The data suggest a range of psychosocial and physical health benefits. Although there are limitations in attributing causality in uncontrolled studies, the data seem to indicate a reversal of the expected downward trends in some aspects of participants' health, and suggest that this approach is worth further investigation.

Efficiency, effectiveness and productivity of marketing in services

How can a service firm right-size marketing expenses and yet strive to maximize revenue? This paper represents the first attempt to model these efficiency and effectiveness issues using a 49-unit Asia–Pacific hotel chain as illustration. We employ a triangular DEA model with total expenses (controlling for number of rooms) as the raw input, marketing expenses as intermediate output/input and revenues from room rentals and F&B as final outputs. We infer that efficiency tails off when more than 12% of the budget is expended on marketing activities. In terms of effectiveness, we find that all the units rated as relatively inefficient can accrue increasing returns to scale in revenues from marketing activities. By contrast, in the productivity stage linking the raw inputs to the revenues, we observe mostly decreasing returns to scale. Our results highlight the crucial role of marketing in service organizations.

Structural panel industry evolution: Implications for innovation and new product development

Industrial organization theory suggests that innovativeness differs across the industry life cycle. Product innovation is high at the beginning of an industry life cycle and diminishes over time. Process innovation is initially low, peaks later in the life cycle and eventually tails off to a level similar to product innovation. However, when a competing product is introduced, companies producing a late life-cycle product tend to increase their product innovation as a response to the competitive threat. This study tests this theory in the context of the North American structural panel industry by comparing plywood, a product in the decline stage of the product life cycle, to oriented strandboard (OSB), a product in the growth stage of the product life cycle. The two industry sectors are compared based on their product innovativeness, structure of new product development (NPD) processes, and product specialization. According to theory, plywood mills should be stronger in each of these areas resulting from response to the competitive threat from OSB. Although these constructs are useful in differentiating between plywood and OSB producers, findings are inconsistent with theory. Oriented strandboard mills were found to be more product-innovative and to use a more structured NPD process than plywood mills. On the other hand, consistent with theory, plywood mills were found to have a more specialized product line. Implications for industry and suggestions for future research are provided.

The Incidence of Dementia in England and Wales: Findings from the Five Identical Sites of the MRC CFA Study

BackgroundAlthough incidence of dementia is known to vary between nations, variation within country has not been explored because most incidence studies are single site or have insufficient numbers to compare sites. Few countries have conducted multisite incidence studies in order to facilitate national comparisons. This study aims to provide robust measures of the variation of the incidence of dementia across sites within England and Wales and produce overall estimates by age and sex.Methods and FindingsThe Medical Research Council Cognitive Function and Ageing Study used identical methodology in five diverse sites across the United Kingdom, each with different risk patterns and mortality rates. Incidence has been estimated using likelihood-based methods between the first two waves of interviews. Incidence rates rise with age, particularly above the age of 75 y, from 7.4 (95% confidence interval, 3.6–16.1) per 1,000 person years at age 65–69 y to 84.9 (95% confidence interval, 63.0–107.8) per 1,000 person years at age 85 y and above. The rate of increase for both sexes is marked, and continues into the oldest age groups. Hence, it is estimated that approximately 180,000 new cases of dementia occur in England and Wales each year. There is no convincing evidence of variation across sites, and incidence rates do not reflect the variations in the prevalence of possible risk factors in these sites.ConclusionThere is no evidence, within England and Wales, of variation in dementia incidence across sites. Dementia incidence rates do not tail off at the oldest ages.

Tracing the Nuclear Accretion History of the Red Galaxy Population

We investigate the evolution of the hard X-ray luminosity of the red galaxy population using a large sample of 3316 red galaxies selected over a wide range in redshift (0.3<z<0.9) from a 1.4 deg^2 region in the Bootes field of the NOAO Deep Wide-Field Survey (NDWFS). The red galaxies are early-type, bulge-dominated galaxies and are selected to have the same evolution corrected, absolute R-band magnitude distribution as a function of redshift to ensure we are tracing the evolution in the X-ray properties of a comparable optical population. Using a stacking analysis of 5-ks Chandra/ACIS observations within this field to study the X-ray emission from these red galaxies in three redshift bins, we find that the mean X-ray luminosity increases as a function of redshift. The large mean X-ray luminosity and the hardness of the mean X-ray spectrum suggests that the X-ray emission is largely dominated by AGN rather than stellar sources. The hardness ratio can be reproduced by either an absorbed (N_H ~2 x 10^22 cm^-2) Gamma=1.7 power-law source, consistent with that of a population of moderately obscured Seyfert-like AGN, or an unabsorbed Gamma=0.7 source suggesting a radiatively inefficient accretion flow (e.g., an advection-dominated accretion flow). We also find that the emission from this sample of red galaxies constitutes at least 5% of the hard X-ray background. These results suggest a global decline in the mean AGN activity of normal early-type galaxies from z~1 to the present, which indicates that we are witnessing the tailing off of the accretion activity onto SMBHs in early-type galaxies since the quasar epoch.

The Whole-Life Impacts of Transport-Charging Interventions on Business Performance: A Time-Marching Framework

A major concern of business with respect to transport-charging interventions is the context of revenue-investment policy, particularly how the timing of improvements may alter the time lags between fewer car journeys and more public transport journeys, and the problems for business in the intervening periods. The authors present a conceptual framework and case study of the whole-life effects on business performance. The impacts of charging occur as a sequence of gradually interacting changes, rather than as a single set of impacts, and positive amenity effects brought about through revenue hypothecation occur incrementally, taking years to achieve full effect. In the case study, a Delphi panel of business leaders predicted the time-marching effects of workplace-parking levies and road-user charging over a 24-year period in Nottingham. The findings revealed that the temporal nature of hypothecation results in minor fluctuations in performance for some business sectors in the first few years, but that these tail off as benefits gradually overwhelm disbenefits resulting in modest increases in performance for most sectors in the medium to long term. Many local authorities are reluctant to implement charging interventions due to concerns about economic vitality; it is expected that the results will inform policy and future research in this area.

Effect of Sputtering Target Power on Preferred Orientation in nc-TiN/a-SiN&lt;sub&gt;x&lt;/sub&gt; Nanocomposite Thin Films

Nanocrystalline TiN (or nc-TiN) has been imbedded in amorphous silicon nitride (a-SiNx)matrix to form a nanocomposite thin film (nc-TiN/a-SiNx) via magnetron sputtering deposition on silicon wafer. Two important effects of the Si3N4 sputtering target power on the formation of nc-TiN/a-SiNx have been studied: (1) Aside from forming a-SiNx in the matrix, Si atoms also imbed into TiN to form (Ti,Si)N solid solution crystallites. At low target power, the solid solution is substitutional. With increase of power, the amount of silicon “dissolved” in the TiN crystallite increases, and in the meantime, the interstitial components increase which is manifested in the increase in the TiN lattice parameter. (2) The crystallites have a preferred orientation varying with the deposition target power. As conveniently described by the coefficient of texture, the degree of preferred orientation along [111] direction decreases and finally tails off with increase of power. At the same time, the crystallites orient along [200] and [220] direction and eventually [220] direction dominants.

Temporal relationship between the occurrence of fresh noma and the timing of linear growth retardation in Nigerian children

Fresh noma (cancrum oris) occurs predominantly in children <4 years of age. The key risk factors are poverty, malnutrition and infections. Evolution from an intraoral inflammation to a grotesque oro-facial gangrene is very rapid. We assessed potential relationship between the occurrence of fresh noma and linear growth retardation (LGR) which is prevalent in deprived Third World infants/children between ages 3 and 30 months. LGR is attributed to malnutrition and chronic immunostimulation by environmental antigens. Anthropometric evaluation of children (n = 91) with fresh noma, ages 0-8 years, in relation to US National Center for Health Statistics Reference values was carried out. Age-matched noma-free, poor village children (n = 151) from similar communities as noma cases, and elite urban children (n = 132) served as control groups. Heights and weights were measured and the height for age (HAZ), weight for age (WAZ) and weight for height (WHZ) scores calculated as indices of stunting, underweight and wasting respectively. Serum level of interleukin (IL)-18, a multifunctional cytokine, was also measured. In the age groups 0-4 and 4-8 years, the percentages of noma children <-2.0SD were 91% and 67% respectively. The corresponding values for the village children were 37% and 24% and significantly different (P < 0.001) from the noma group. Only 7% of the elite children aged 4-8 years were stunted. Low body weight and wasting were prominent features of village and noma groups, but more marked in the latter. Associated with noma was a profound increase (P < 0.001) in IL-18 in comparison with urban controls, and a 34% non-statistically significant increase relative to the village control group. Among other functions, IL-18 induces several pro-inflammatory cytokines and the matrix metalloproteinases, influences long bone growth, and consequently may be relevant to growth retardation seen in poor village children and noma victims. These results suggest that occurrence of fresh noma was probably programmed very early in life by malnutrition and chronic infections resulting from replacement of breast milk with contaminated, inferior substitutes. Although not investigated, we speculate that children with fresh noma might also be victims of intrauterine growth retardation as noma is most prevalent during the infantile phase of child growth which starts at mid-gestation and tails off at 4 years.

Enzyme hyperactivity in AOT water-in-oil microemulsions is induced by ‘lone’ sodium counterions in the water-pool

Water-in-oil microemulsions are thermodynamically stable single-phase dispersions of water and surfactant within a continuous oil phase. The classical ternary system, based on the surfactant sodium bis(2-ethylhexyl)sulfosuccinate ('AOT'), water and an alkane such as n-heptane, is an optically transparent monodispersion of spherical water-droplets coated with a close-packed surfactant monolayer and the droplet radius is, to a good first approximation, directly proportional to the molar water: surfactant ratio, R. Enzymes dissolved in the water droplets retain activity and stability. These systems have attracted interest as media for biotransformations. Principally based upon studies in AOT-stabilized w/o microemulsions, a peculiar feature of the kinetics of enzyme-catalyzed reactions has long been apparent: the reaction rate characteristically increases from around zero at R=3, through a maximum, in the range R= 10-20, and thereafter decreases again, so that plots of rate vs. R are characteristically 'bell-shaped'. Furthermore, at optimal R, enzymes seem to be 'hyperactive', i.e., they are more active, by a modest but significant factor of 2-3-fold, than in aqueous solution. In this paper we propose the hypothesis that this kind of R-dependence arises because of the presence of freely mobile lone surfactant counterions (Na+) within the water-pool. These ions have no charge partners within the water pool and consequently have a high electrochemical potential. According to our model, lone counterions facilitate the hydrolysis of ester or amide substrates, for example, by stabilizing the tetrahedral intermediate formed during the reaction through ion-pairing with the carbonyl oxygen of the substrate, thus facilitating transfer of negative charge from the carbonyl carbon as it is attacked by the incoming nucleophile. An expression for the relationship between the concentration of free counterions in the water-pool and the compositional parameter R leads directly, through Debye-Hückel theory, to an expression for the relationship between the reaction rate and R, log k(R)= log k(o) + C(1/R)1/2 where k(R) is the rate constant at some finite R, k(o) is the rate constant extrapolated to R = infinity and C is an R-independent coefficient. For enzymes that display bell-shaped kinetics, such as bovine alpha-chymotrypsin and Chromobacterium viscosum lipase, the descending part of the plot (i.e. from optimal R to high R) obeys this equation very well. Inspection of the above equation shows that the rate constant, k(R) is greater than k(o). Furthermore it is reasonable to equate k(o) with k(aq), the aqueous solution value of k since the condition R = infinity may be equated with the condition of infinite dilution with respect to counterions, so eliminating their specific effect on the kinetics. It follows from the inequality, k(R) > k(o) approximately equal to k(aq), that the enzyme is 'hyperactive' in the microemulsion compared with aqueous solution. We show that this is indeed the case for the chymotrypsin-catalyzed hydrolysis of N-trans-cinnamoylimidazole and the lipase catalyzed hydrolysis of 4-nitrophenyl acetate. The tailing off of enzyme activity at low R (< 10) is most likely due to conformational immobilization, probably due to partial dehydration in these low-water preparations (water activity, a(w), drops off rapidly below R = 15). We show that the reaction of glycylglycine with 4-nitrophenyl acetate, a 'hyperactive' non-enzymic reaction, does not suffer from this effect and obeys the above equation across the whole range of R.

Estimating Trip Generation of Elderly and Disabled People

The aging of populations has implications for trip-making behavior and the demand for special transport services. The London Area Travel Survey 2001 is analyzed to establish the trip-making characteristics of elderly and disabled people. Ordinal probit models are fitted for all trips and for trips by four purposes (work, shopping, personal business, and recreational), with daily trip frequency as the latent variable. A log-linear model is used to analyze trip length. A distinction must be made between young disabled, younger elderly, and older elderly people. Retired people initially tend to make more trips, but as they become older and disabilities intervene, trip making tails off. Household structure, income, car ownership, possession of a driver's license, difficulty walking, and other disabilities are found to affect trip frequency and length to a greater or lesser extent.

Estimating Trip Generation of Elderly and Disabled People: Analysis of London Data

The aging of populations has implications for trip-making behavior and the demand for special transport services. The London Area Travel Survey 2001 is analyzed to establish the trip-making characteristics of elderly and disabled people. Ordinal probit models are fitted for all trips and for trips by four purposes (work, shopping, personal business, and recreational), with daily trip frequency as the latent variable. A log-linear model is used to analyze trip length. A distinction must be made between young disabled, younger elderly, and older elderly people. Retired people initially tend to make more trips, but as they become older and disabilities intervene, trip making tails off. Household structure, income, car ownership, possession of a driver's license, difficulty walking, and other disabilities are found to affect trip frequency and length to a greater or lesser extent.

Metal–Semiconductor–Metal AlN Mid-Ultraviolet Photodetectors Grown by Magnetron Reactive Sputtering Deposition

Metal–semiconductor–metal (MSM) AlN mid-ultraviolet (mid-UV) photodetectors were fabricated. AlN layers were grown on GaN substrates by magnetron reactive sputtering deposition. The AlN photodetectors exhibited a high responsivity at wavelengths from 210 nm to 190 nm, and the response tails off at a wavelength of 220 nm. The responsivities at 200 nm at biases of 5 V and 10 V were 1.08 and 3.51 A/W, respectively. When the reverse voltage was higher than 7 V, responsivity increased almost linearly with reverse voltage. The responsivity at 25 V was calculated to be approximately 14.9 A/W.

Using evidence-based dissemination and implementation strategies to improve routine communication between general practitioners and community mental health teams

Aims and MethodTo improve the quality of written communication between general practitioners (GPs) and community mental health team (CMHT) members concerning patients newly referred to two inner-city CMHTs. Following a benchmark audit of a random sample of referral and assessment letters, locally agreed good practice protocols were shared widely, accompanied by a dissemination and implementation strategy.ResultsSignificant improvements occurred in both GP and CMHT letters; these were most dramatic after 1 year, but tailed off considerably in the second year despite continued efforts to implement the protocols' standards.Clinical ImplicationsPlanned dissemination and implementation strategies can help to improve routine clinical communication between CMHTs and GPs through the use of good practice protocols, thus improving shared working between primary and secondary care providers.

Thorough Examination of a Wittig−Horner Reaction Using Reaction Calorimetry (RC-1), LabMax, and ReactIR

The kinetics and thermodynamics of a Wittig−Horner reaction was investigated, together with side reactions such as the hydrolysis of benzyl phosphonate. It was found that the water content in the reaction mass has a crucial effect on the rates both of the unwanted hydrolysis of the phosphonate and of the main reaction. The reaction was found to be fourth-order. That means that the reaction is very fast at the start but tails off towards the end. On the basis of the kinetic and thermodynamic parameters, a simulation of the whole process was made, including the expected concentrations of the product under the required conditions (temperature, reactor characteristics, etc.). The experimental values of the concentrations were obtained from spectra collected via a rapid reaction mode in the ReactIR (a spectrum was collected every ∼3 s). Exact agreement between experimental and theoretical values confirms the correctness of the mathematical model and enables right planning of the industrial process.

Self-assembly of a ferrocene-substituted porphyrin capable of electrochemically sensing neutral molecules via a "tail on-tail off" process.

The supramolecular assembly of a ferrocene-porphyrin conjugate allowed ferrocene-based electrochemical sensing of the metalloporphyrin axial coordination via a "tail on-tail off" binding process.

Investigation of the glassy state of the Ge 10Sb xSe 90− x system

The effect of the heating rate φ (5⩽ φ⩽20 K/min) on the glass transition temperature T g for the semiconducting Ge 10Sb x Se 90− x system (5⩽ x⩽25) was studied. The obtained results reveal that an exponential relation between T g and φ. An empirical equation of the Arrhenius form describes this dependence has been deduced. The correlation between the pre-exponential factor σ 0 and the activation energy E a below and above the glass transition temperature has been studied. The Meyer–Neldel (MN) rule has been observed to be valid in the investigated system within the composition range 10⩽ x⩽25. These results indicate that the valence and conduction bands tail off exponentially with energy. It was also found that the rate of variation of the glass transition temperature with the energy gap in the solid (rigid) state of the investigated compositions varies in the same way as the soft (floppy) state.

A Technical Review of Column Generation in Integer Programming

This paper provides a technical review of topics relevant to applying column generation methods to solve integer programs but emphasizes formulation issues as a means of achieving its goal, which is to bridge the gap between methodological development and application. Type I, II and III column generation approaches are described in detail and each is demonstrated by a set of prototypical formulations that provide a historical perspective of milestone contributions. Technical issues, including formulation, context, algorithm design and implementation are also related. Formulation issues encompass the restricted master problem (RMP) and subproblem (SP) structure, symmetry, complexity and the Integrality Property. Context issues comprise theoretical principles, dealing with binary or general integer variables and generating rows as well as columns. Algorithm design issues include branching strategies, SP solution strategies and problem-specific techniques. Implementation issues include determining an initial basic feasible solution, managing a pool of generated columns, optimizing the RMP at each iteration, and handling degeneracy and tailing off.

Calculating the contrasts that retinal ganglion cells and LGN neurones encounter in natural scenes

Visual responses are known to depend on stimulus contrast and not simply on the absolute levels of retinal illumination. Here, we have determined the contrasts that mammalian retinal ganglion cells and lateral geniculate neurones (LGN) are likely to encounter in real world scenes. Local contrasts were calculated in 135 calibrated images of a variety of real world scenes using contrast operators that closely mirror the characteristic receptive-field organisation of mammalian retinal ganglion cells and LGN neurones. We have found that the frequency distribution of the calculated local contrasts has a pronounced peak at zero contrast and that it tails off roughly exponentially with increasing positive and negative contrasts; about 90% of the contrasts in the images were within the equivalent range of ±0.5 Michelson and Weber contrasts. Further analysis suggests that the characteristic forms of the contrast-response functions of mammalian retinal and LGN neurones are matched to the range of contrasts that they experience when viewing real world images.

Canonical functions for dispersal-induced synchrony.

Two processes are universally recognized for inducing spatial synchrony in abundance: dispersal and correlated environmental stochasticity. In the present study we seek the expected relationship between synchrony and distance in populations that are synchronized by density-independent dispersal. In the absence of dispersal, synchrony among populations with simple dynamics has been shown to echo the correlation in the environment. We ask what functional form we may expect between synchrony and distance when dispersal is the synchronizing agent. We formulate a continuous-space, continuous-time model that explicitly represents the time evolution of the spatial covariance as a function of spatial distance. Solving this model gives us two simple canonical functions for dispersal-induced covariance in spatially extended populations. If dispersal is rare relative to birth and death, then covariances between nearby points will follow the dispersal distance distribution. At long distances, however, the covariance tails off according to exponential or Bessel functions (depending on whether the population moves in one or two dimensions). If dispersal is common, then the covariances will follow the mixture distribution that is approximately Gaussian around the origin and with an exponential or Bessel tail. The latter mixture results regardless of the original dispersal distance distribution. There are hence two canonical functions for dispersal-induced synchrony

Scattering of short laser pulses from trapped fermions

We investigate the scattering of intense short laser pulses off trapped cold fermionic atoms. We discuss the sensitivity of the scattered light to the quantum statistics of the atoms. The temperature dependence of the scattered light spectrum is calculated. Comparisons are made with a system of classical atoms who obey Maxwell-Boltzmann statistics. We find the total scattering increases as the fermions become cooler but eventually tails off at very low temperatures (far below the Fermi temperature). At these low temperatures the fermionic degeneracy plays an important role in the scattering as it inhibits spontaneous emission into occupied energy levels below the Fermi surface. We demonstrate temperature dependent qualitative changes in the differential and total spectrum can be utilized to probe quantum degeneracy of trapped Fermi gas when the total number of atoms are sufficiently large $(\geq 10^6)$. At smaller number of atoms, incoherent scattering dominates and it displays weak temperature dependence.