Low Activity Rates Research Articles

Gender, Discontinued Careers and Low Activity Rates in a Long Life Society

While long life society constitutes progress in terms of healthier, better and longer lives, it is also associated with higher pension and health expenditures to an extent that threatens the long term adequacy and sustainability of existing welfare systems. It therefore requires adaptation on the part of society and of social institutions and policies, in particular the labour market and the welfare systems, in order to stem or even reduce the growing dependency ratios of the population. In this context, the gender dimension is crucial for any policies that aim at improving the effectiveness of labour markets and social and economic inclusion. This article thus starts by signalling the six main changes that have occurred in the European Union and US labour markets and the workforce, which concern in particular women in all age groups. It then highlights the main responses of the welfare systems to these changes, emphasizing activation measures and indicating their successes and shortcomings—as illustrated by the Danish and UK experience. The article concludes by suggesting policies that may enhance female activity and employment rates, from both the labour supply and demand perspectives.

Use of serial analysis of gene expression (SAGE) technology reveals new granulocytic markers

Because of its short life span in blood, its low RNA content and its highly condensed nucleus, the granulocyte was initially considered as a terminally differentiated cell unable to express novel genes. However, mature granulocytes still contain a variety of mRNAs and may respond to external stimuli by rapid and complex changes in gene expression. The present work was undertaken to provide a wider view of the gene expression profile in unstimulated circulating PMNs. We used serial analysis of gene expression (SAGE) adapted to downsized extracts (SADE) to cope with their small mRNA content. As cell samples of the highest degree of purity were crucial for this project, we adapted a magnetic cell sorting method to reach the required high levels of purity (99.55±0.19%) together with low activation rates (1.37±0.28). We analyzed 20787 tags identifying 8547 different transcripts, of which 47.8% were unknown, 34.6% were transcripts of known genes, and 13.8% matched with expressed sequence tags (EST). Highly expressed genes were those involved in cell mobility, diapedesis, cell signaling and destruction of micro-organisms. In addition, this method led to the identification of genes which had not previously been reported in granulocytes. These results could provide new molecular markers and a reliable reference for the investigation of pathologies involving alteration of the granulocyte gene expression profile.

Archaeal phylotypes in a metal‐rich and low‐activity deep subsurface sediment of the Peru Basin, ODP Leg 201, Site 1231

ABSTRACTSite 1231 of the Ocean Drilling Project (ODP) was characterized by low concentrations of organic carbon, as well as low cell numbers and biological activity rates. A 16S rRNA survey was performed in order to analyse the microbial community composition of these central oceanic sediments. Archaeal 16S rRNA genes from subsurface sediments at Site 1231 (1.8, 9.0, and 43 mbsf) were affiliated with uncultured lineages from subsurface or hydrothermal vent habitats. Members of the Marine Group I (MGI) found in the 1.8 mbsf sediment formed distinct clusters, some dominated by phylotypes from Site 1231 and other subsurface environments. The archaeal community survey at Site 1231 indicated that several archaeal lineages were widespread in subsurface environments, marine sediments as well as hydrothermal habitats.

Duality of serotonin- N-acetyltransferase in the gilthead seabream ( Sparus aurata): molecular cloning and characterization of recombinant enzymes

Serotonin- N-acetyltransferase (arylalkylamine- N-acetyltransferase, AANAT) is the key enzyme in the biosynthesis of melatonin in the pineal gland and retinal photoreceptors. Rhythmic AANAT activity drives rhythmic melatonin production in these tissues. The presence of two AANATs, AANAT1 and AANAT2, has been previously demonstrated in three fresh water teleosts. This duality, the result of early gene duplication, is unique to teleost species. In this study, the cDNAs encoding for AANAT1 and AANAT2 were cloned from a marine fish, the gilthead seabream (sb, Sparus aurata). Northern blot hybridization analysis indicates that sbAANAT1 and sbAANAT2 are exclusively expressed in the retina and pineal gland, respectively. Bacterially expressed recombinant sbAANATs exhibit differential enzyme kinetics. Recombinant retinal sbAANAT1 has relatively high substrate affinity and low activity rate; it is inhibited by high substrate and product concentrations. In contrast, recombinant pineal sbAANAT2 exhibits low substrate affinity and high activity rate and is not inhibited by substrates or products. The two recombinant enzymes also exhibit differential substrate preference. Retinal sbAANAT1 acetylates a range of arylalkylamines while pineal sbAANAT2 preferentially acetylates indoleethylamines, especially serotonin. The different spatial expression patterns, enzyme kinetics, and substrate preferences of the two sbAANATs support the hypothesis that, as a consequence of gene duplication, teleosts have acquired two AANATs with different functions. Pineal AANAT2 specializes in the production of large amounts of melatonin that is released into the circulation and exerts an endocrine role. Retinal AANAT1, on the other hand, is involved in producing low levels of melatonin that execute a paracrine function. In addition, retinal AANAT1 may carry out an as yet unknown function that involves acetylation of arylalkylamines other than serotonin.

Ectomesenchymal chondromyxoid tumour of the anterior tongue

Ectomesenchymal chondromyxoid tumour (ECT) of the anterior tongue was first described in 1995. To date, only 23 cases have been reported in the literature. Two new cases of ECT have been described, with immunohistochemical analysis including cytokeratin (CK) profile, GFAP, S-100 protein, SMA, CD-57, EMA, desmin and Ki67. Tumour cells showed intense and diffuse staining for GFAP and diffuse staining for S-100 protein. Pan-keratin, high- and low-molecular-weight CK, CK 7, 8, 18, 19 and 20 were negative. Tumour cells were also negative for desmin, SMA, CD-57 and EMA. Ki67 was positive in only scattered cells. The findings of the present study support the suggested ectomesenchymal origin for ECT, rather than myoepithelial salivary gland origin. The low Ki67 expression is in agreement with the low growth rate, small size and lack of mitotic activity in the present cases, as well as in those previously described.

A community-oriented primary care demonstration project: refining interventions for cardiovascular disease and diabetes.

We describe a community-oriented primary care project that implemented all 5 steps of the formal model. Data are presented on cardiac risk factors, protective behaviors, health locus of control, and stage of readiness for change in an African American community. We discuss the use of these data to refine our health promotion interventions. We undertook a cross-sectional study of self-reported health behaviors from a door-to-door household survey of a geographically-defined community. Trained community members administered the survey questionnaire, which was completed in 386 of 557 randomly sampled households (response rate 69.4%). Qualitative discussions of survey results with 2 community groups were taped, transcribed, and analyzed for common themes. Compared with their counterparts, respondents who were older than 65 years (P = .0006), who had hypertension (P <.0001), and who had diabetes (P = .001) had higher mean scores for powerful others locus of control. Rates for physical activity and low-fat diet indicators were low compared with national statistics. Most respondents reported a maintenance stage of change for exercise (46.2%) and diet (57.5%). Group discussions found lack of local exercise resources and high-quality grocery stores to be major barriers to health behavior change. Ministers and physicians were identified as important powerful others. This study documents low rates of physical activity and healthy dietary patterns and describes recent interventions to address environmental barriers to behavior change. The association between powerful others locus of control and specific cardiac risk factors has prompted a greater emphasis on developing faith-based interventions and renewing physician-counseling efforts. Stage of readiness for change findings have prompted strategies to disseminate existing diet and physical activity recommendations more effectively.

Self‐passivation mechanisms in clusters of N dopants in SiC

Although having proved to be one of the most successful n-type dopant in SiC for many applications, nitrogen exhibits a troublesome nature when a high-dose implantation is required. Experimental measurements showed that phosphorus is more suited in such conditions. We proposed previously that the reason may be the self-passivation of the N clusters that are likely to form in the high-concentration limit. In this paper we discuss in details the passivation mechanisms that are relevant for the different N aggregates that can form and that are the ultimate responsible of the low activation rate of high-dose N-implanted SiC. We have found that all the N complexes that are likely to form in SiC do self-passivate. However, the passivation mechanisms are not always the same and they are due in turn to the formation of a bound molecule or to a charge-trapping effect. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Welfare and Labour Market Reforms: A New Framework for Social Dialogue and Collective Bargaining?

This article examines the challenges raised for the social partners and collective bargaining by recent and planned reforms of the welfare state, necessitated by major changes in the labour market and the socio-economic context over the past three decades. The article highlights thesechanges as well as their policy implications. It shows how government policy has been constrained by a broad range of factors: notably, high unemployment, low labour force activity rates, growing female participation in the labour market, changes in family structures, demographic ageing, the shift to a post-industrial economy, thespread of economic liberalism and the European Growth and Stability Pact. Whilethere is no unique formula to address the complex issues involved in welfare reform, a comprehensive policy mix is required and seems feasible only through patient consensus building among all stakeholders, particularly the social partners. This is the lesson of successful reforms and appears to be the major challenge for preserving social cohesion and reviving collective bargaining.

Selective instability: maternal effort and the evolution of gene activation and deactivation rates.

We previously used simulations of gene expression to demonstrate that rapid activation and deactivation rates stabilized outcomes in stochastic systems. We hypothesized that transient single allele inactivation of an autosomal gene during gametogenesis or very early embryogenesis could have a selective advantage if it permits the functional sampling of each allele and precludes committing maternal effort to an embryo with a deleterious mutation. To test this hypothesis, we simulated the evolution of gene expression activation and deactivation rates and imposed two different selective pressures on the populations: (a). late selection against individuals that cannot maintain a threshold level of gene product that occurs after the investment of maternal effort (i.e., after birth); or (b). early selection: in addition to late selection, maintenance of the gene product above a threshold level was necessary for early development prior to commitment of maternal effort. We found that the opportunity to save reproductive effort from early selection caused the evolution of higher deactivation rates and lower activation rates than in the late selection condition. Thus, we predict that in the special case where early selection can save maternal investment in non-viable offspring, gene expression activation rates and deactivation rates might be selected to permit sampling of the product from each allele.

Ex-Yugoslavs in the Austrian and Swedish labour markets: The significance of the period of migration and the effect of citizenship acquisition

This paper assesses the labour market integration of ex-Yugoslav immigrants in Austria and Sweden in terms of three relevant structural characteristics of the two societies: immigration policies, labour markets and welfare regulations. The Austrian 1996 micro-census and the Swedish 1997 labour force survey data are utilised to explore the labour market attainment of ex-Yugoslav citizens in Austria and Sweden in terms of four outcomes: labour force participation, unemployment, economic sector concen tration and occupational status. The labour market situations of pre-1973 immigrants in Sweden and Austria were found to be quite similar, while more recent immigrants to Sweden show distinctly lower activity rates and higher unemployment risks compared to natives than do their counterparts who went to Austria. If successful in finding a job, recent Yugoslav immigrants in Sweden managed to enter more prestigious occupations than their compatriots in Austria, but immigrants in both countries are disadvantaged if compared to the native-born. The study demonstrates that, when controlling for period of migration, citizenship per se does not influence labour market outcomes in Sweden. In Austria, in contrast, non-citizens have higher risks of employment in the non-tertiary sector and hold jobs of lower occupational status.

Extended hatching periods in the subantarctic lithodid crabs Lithodes santolla and Paralomis granulosa (Crustacea: Decapoda: Lithodidae)

Temporal pattern of hatching was studied in the subantarctic lithodid crabs Lithodes santolla (Molina) and Paralomis granulosa (Jaquinot) from the Argentine Beagle Channel. In both species, larval hatching occurred in low daily numbers over an extended period of up to several weeks, depending on hatch size. Low daily hatching activity and low oxygen-consumption rates in freshly hatched P. granulosa larvae are discussed as life history adaptations to, and/or physiological constraints by, the environmental conditions of high latitudes.

Phagocytosis and Allogeneic T Cell Stimulation by Cultured Human Osteoblast-Like Cells

Background/Aims: The antigen phenotype of human osteoblast-like cells suggests that they are related to other cellular populations and may also have immunologic functions in common. Methods: Flow cytometry and transmission electron microscopy were used to show the phagocytotic activity of osteoblast-like cells in culture. The allogeneic stimulation of T cells by human osteoblast-like cells was determined by the measurement of T cell proliferation. Results: We demonstrated in vitro that human osteoblast-like cells isolated from normal bone specimens obtained during mandibular osteotomy can phagocytose particles of different nature and size and can stimulate allogeneic T cells. Phagocytosis of microorganisms (E.coli, Klebsiella or C. albicans) was observed, although at a very low rate of activity in comparison with the phagocytosis of latex particles. Conclusion: Our results suggest that human osteoblast-like cells may perform immunologic functions and act as antigen presentation cells.p>

Départ à la retraite. Une perspective internationale

Important international differences persist with respect to the activity rates and the age of retirement of elderly workers. While some continental European countries face very low activity rates, the same does not hold true for many other developed countries. We illustrate the role of individual incentives in explaining this observed retirement pattern.

Nitrate ammonification and its relationship to the accumulation of ammonium in a Vertisol subsoil

High concentrations of ammonium (up to 270 kg N/ha) have been observed in a Vertisol soil below 1 m depth near Warra in south-east Queensland. This study examined the possibility that increased water movement into the subsoil after the removal of native vegetation, and a subsequent increase in periods of waterlogging, could have triggered nitrate ammonification and be responsible for the production of ammonium. Two incubation experiments were conducted to test this hypothesis. The first involved the incubation of repacked cores that had been amended with 30 mg N/kg of 5 atom% 15N nitrate under low oxygen conditions for a period of 360 days. Over this time period the 15N enrichment of the exchangeable ammonium fraction was monitored in order to detect any reduction of nitrate to ammonium. The second experiment involved the incubation of soil amended with 30 mg N/kg of 5 atom% 15N nitrate under waterlogged and low oxygen conditions for 75 days. During this period the redox potential of the soil was monitored using a field test to determine if reducing conditions would develop in this soil over a period of waterlogging, combined with the monitoring of any nitrate reduction to ammonium. The results of these experiments indicated that a small amount of nitrate ammonification (&lt;0.1 mg N/kg) could be observed in the Warra subsoil, but that unless the rate of reduction were to significantly increase with time, this could not account for the accumulation of ammonium observed in the field. The environmental conditions that would make either dissimilatory or abiotic nitrate ammonification favourable were not observed to develop. Consequently, it has been concluded that the observed nitrate ammonification occurred via an assimilatory pathway. Due to the low rate of microbial activity in this subsoil it is considered unlikely that this process was responsible for the subsoil ammonium accumulation at Warra.

An Empirical Model for Earthquake Probabilities in the San Francisco Bay Region, California, 2002-2031

The moment magnitude M 7.8 earthquake in 1906 profoundly changed the rate of seismic activity over much of northern California. The low rate of seismic activity in the San Francisco Bay region (SFBR) since 1906, relative to that of the preceding 55 yr, is often explained as a stress-shadow effect of the 1906 earthquake. However, existing elastic and visco-elastic models of stress change fail to fully account for the duration of the lowered rate of earthquake activity. We use variations in the rate of earthquakes as a basis for a simple empirical model for estimating the probability of M ≥6.7 earthquakes in the SFBR. The model preserves the relative magnitude distribution of sources predicted by the Working Group on California Earthquake Probabilities' (WGCEP, 1999; WGCEP, 2002) model of characterized ruptures on SFBR faults and is consistent with the occurrence of the four M ≥6.7 earthquakes in the region since 1838. When the empirical model is extrapolated 30 yr forward from 2002, it gives a probability of 0.42 for one or more M ≥6.7 in the SFBR. This result is lower than the probability of 0.5 estimated by WGCEP (1988), lower than the 30-yr Poisson probability of 0.60 obtained by WGCEP (1999) and WGCEP (2002), and lower than the 30-yr time-dependent probabilities of 0.67, 0.70, and 0.63 obtained by WGCEP (1990), WGCEP (1999), and WGCEP (2002), respectively, for the occurrence of one or more large earthquakes. This lower probability is consistent with the lack of adequate accounting for the 1906 stress-shadow in these earlier reports. The empirical model represents one possible approach toward accounting for the stress-shadow effect of the 1906 earthquake. However, the discrepancy between our result and those obtained with other modeling methods underscores the fact that the physics controlling the timing of earthquakes is not well understood. Hence, we advise against using the empirical model alone (or any other single probability model) for estimating the earthquake hazard and endorse the use of all credible earthquake probability models for the region, including the empirical model, with appropriate weighting, as was done in WGCEP (2002). Manuscript received 11 January 2002.

A simulation study of 6H-SiC Schottky barrier source/drain MOSFET

A novel SiC metal-oxide-semiconductor field-effect transistor (SiC SBSD-MOSFET) with Schottky barrier contacts for source and drain is presented in this paper. This kind the device gives a fabrication advantage of avoiding the steps of ion implantation and annealing at high temperatures of the conventional SiC MOSFET. Also It has no problems of crystal damage caused by ion implantation and low activation rate of implanted atoms. The operational mechanism of this device is analyzed and its characteristics are comparable to the conventional SiC MOSFET from the simulation with MEDICI. The effects of different metal workfunctions, oxide thickness, and gate length on the device performance are discussed.

Physiological response properties of neurons in the superior paraolivary nucleus of the rat.

The superior paraolivary nucleus (SPON) is a prominent nucleus of the superior olivary complex. In rats, this nucleus is composed of a morphologically homogeneous population of GABAergic neurons that receive excitatory input from the contralateral cochlear nucleus and inhibitory input from the ipsilateral medial nucleus of the trapezoid body. SPON neurons provide a dense projection to the ipsilateral inferior colliculus and are thereby capable of exerting profound modulatory influence on collicular neurons. Despite recent interest in the structural and connectional features of SPON, little is presently known concerning the physiological response properties of this cell group or its functional role in auditory processing. We utilized extracellular, in vivo recording methods to study responses of SPON neurons to broad band noise, pure tone, and amplitude-modulated pure tone stimuli. Localization of recording sites within the SPON provides evidence for a medial (high frequency) to lateral (low frequency) tonotopic representation of frequencies within the nucleus. Best frequencies of SPON neurons spanned the audible range of the rat and receptive fields were narrow with V-shaped regions near threshold. Nearly all SPON neurons responded at the offset of broad band noise and pure tone stimuli. The vast majority of SPON neurons displayed very low rates of spontaneous activity and only responded to stimuli presented to the contralateral ear, although a small population showed binaural facilitation. Most SPON neurons also generated spike activity that was synchronized to sinusoidally amplitude-modulated tones. Taken together, these data suggest that SPON neurons may serve to encode temporal features of complex sounds, such as those contained in species-specific vocalizations.

Tuning FlaSh: Redesign of the Dynamics, Voltage Range, and Color of the Genetically Encoded Optical Sensor of Membrane Potential

The optical voltage sensor FlaSh, made from a fusion of a GFP “reporter domain” and a voltage-gated Shaker K + channel “detector domain,” has been mutagenically tuned in both the GFP reporter and channel detector domains. This has produced sensors with improved folding at 37 °C, enabling use in mammalian preparations, and yielded variants with distinct spectra, kinetics, and voltage dependence, thus expanding the types of electrical signals that can be detected. The optical readout of FlaSh has also been expanded from single wavelength fluorescence intensity changes to dual wavelength measurements based on both voltage-dependent spectral shifts and changes in FRET. Different versions of FlaSh can now be chosen to optimize the detection of either action potentials or synaptic potentials, to follow high versus low rates of activity, and to best reflect electrical activity in cell types with distinct voltages of operation.

Tadpoles' responses to risk of fish introduction.

The introduction of predatory species, such as fish, in amphibian breeding sites is one of the many likely causes of amphibian population decline. The existence of inducible or constitutive (permanent) defences is expected to temper the lethal effects of fish on tadpoles. According to current theories on the evolution of phenotypic plasticity, the amphibian species that occur in habitats that are mostly or often fish-free were expected to display inducible defences, while the species that reproduce mainly in fish ponds ought to present constitutive defences. The tested species were Rana dalmatina, Hyla arborea and R. ridibunda, respectively. As expected, R. ridibunda tadpoles were less vulnerable to fish predation than the other species. Nevertheless, all three species exhibited morphological responses in the presence of fish. Their increases in tail area and decreases in body depth were similar. However, behaviour was only modified in R. dalmatina, which exhibited lower activity rates and higher refuge use in the presence of fish cues. Such lower activity rates were related to lower growth and developmental rates. While not detected in this experiment, the existence of inducible defences in the three species suggests the existence of costs of anti-predator defence. Those costs may have delayed effects so that increasing the frequency of fish ponds may exacerbate the impact of delayed costs whatever the species, suggesting that the dynamics of species that are not fish-adverse could also suffer from the introduction of fish.

Nuclear cardiology in the UK: activity and practice 1997.

A questionnaire was sent to 251 nuclear medicine centres asking for details of nuclear medicine activity, and nuclear cardiology activity and practice in 1997. One hundred and seventy-one (68%) centres replied. Nuclear medicine activity was estimated at 11.8 studies/1,000 population/year, and 9.5% of these studies were within cardiology (1.12 studies/1,000/year). Myocardial perfusion imaging (MPI) studies accounted for 77% and radionuclide ventriculography (RNV) for 22% of all nuclear cardiology. On a national basis this represents activity levels of 0.86 and 0.25 studies/1,000/year for MPI and RNV, respectively. Of the 171 responding centres, 102 (60%) performed MPI studies and 81 (79%) of these reported that activity was increasing. However, MPI activity was unevenly distributed between hospitals. Two centres accounted for 13% of total MPI; others had far lower activity rates, and 51/102 (50%) centres performed less than 200 MPI studies/year. Comparison with previous surveys showed that nuclear medicine activity had almost doubled since 1990 (it was 6.0 studies/1,000 population in 1990, 9.3 studies/1,000 in 1994 and 11.8 studies/1,000 in 1997). Over the same period, nuclear cardiology activity had also risen, the greatest increase being seen for the last 3 years (it was 0.7 studies/1,000 population in 1990, 0.82 studies/1,000 in 1994 and 1.12 studies/1,000 in 1997). Despite these encouraging figures, MPI activity for 1997 remained well below that recommended by the British Cardiac Society in 1994 (2.6 studies/1,000/year) as adequate to serve the needs of patients with cardiac disease in the UK; it was also below the European average activity for the same year (2.2 studies/1,000/year). The anticipated increased workload for nuclear cardiology is encouraging despite the wide and varied practice of nuclear cardiology around the UK. The nuclear medicine community now needs to address the issues that will prevent it keeping up with demand, such as restricted camera time, excessive waiting lists and outdated equipment, but also to standardise acquisition and reporting techniques so that all studies, wherever performed, will be of a uniformly high standard.