The dynamics of solo self-employment: Persistence and transition to employership

This study examines dynamics of solo self-employment. In particular, we investigate the extent of true state dependence and cross state dependence, i.e., whether experiencing solo self-employment causally affects the probability of becoming an employer in the future. We use data from the German Socio-Economic Panel to estimate dynamic multinomial logit models. Our results show that the extent of true (cross) state dependence is rather small. The observed persistence in solo self-employment as well as transitions from solo self-employment to employership can largely be explained by observed and unobserved heterogeneity.Diese Studie untersucht die Dynamik der Solo-Selbständigkeit (Verbleib,Zu- und Abgänge). Wir berechnen das Ausmaß genuiner Zustandsabhängigkeit für den Verbleib in Solo-Selbständigkeit und schätzen den kausalen Effekt der Solo-Selbstständigkeit auf die Wahrscheinlichkeit, Arbeitgeber zu werden. Die Berechungen basieren auf dynamischen multinomialen Logit-Modellen, die mit Daten des Sozio-oekonomischen Panels geschätzt wurden. Unsere Ergebnisse deuten auf eine nur geringe genuine Zustandsabhängigkeit hin: Sowohl die beobachtete Persistenz in Solo-Selbständigkeit als auch die Übergänge zum Arbeitgeber-Status lassen sich größtenteils durch (beobachtete und unbeobachtete) individuelle Merkmale erklären

Molecular imaging: novel tools in visualizing rheumatoid arthritis

Molecular imaging is a rapidly emerging field in biomedical research, aiming at the visualization, characterization and quantification of molecular and cellular processes non-invasively within intact living organisms. To sense biological processes such as gene expression, angiogenesis, apoptosis or cell trafficking in vivo, imaging reporter agents that interact specifically with molecular targets and appropriate imaging systems are currently under development. In rheumatoid arthritis, these novel tools will be used to evaluate physiological and pathophysiological processes, to facilitate diagnosis and monitor therapeutic regimens, to enable reliable prognosis and to support the development of new therapies. In this review, we summarize the basic principles of molecular imaging, such as the development of molecular imaging agents, the actual capabilities of different imaging modalities and the most recent advances in molecular imaging, demonstrating the potential of this technology. With regard to their applicability in rheumatic diseases, we discuss potential molecular targets, current experimental approaches and the future prospects for molecular imaging in rheumatoid arthriti

Protecting biodiversity and economic returns in resource-rich tropical forests.

In pursuit of socioeconomic development, many countries are expanding oil and mineral extraction into tropical forests. These activities seed access to remote, biologically rich areas, thereby endangering global biodiversity. Here we demonstrate that conservation solutions that effectively balance the protection of biodiversity and economic revenues are possible in biologically valuable regions. Using spatial data on oil profits and predicted species and ecosystem extents, we optimise the protection of 741 terrestrial species and 20 ecosystems of the Ecuadorian Amazon, across a range of opportunity costs (i.e. sacrifices of extractive profit). For such an optimisation, giving up 5% of a year's oil profits (US$221 million) allows for a protected area network that retains of an average of 65$ 1.7 billion), and uses only marginally less land, to achieve equivalent levels of ecological protection. Applying spatial statistics to remotely sensed, historic deforestation data, we further focus the optimisation to areas most threatened by imminent forest loss. We identify Emergency Conservation Targets: areas that are essential to a cost-effective conservation reserve network and at imminent risk of destruction, thus requiring urgent and effective protection. Governments should employ the methods presented here when considering extractive led development options, to responsibly manage the associated ecological-economic trade-offs and protect natural capital. Article Impact Statement: Governments controlling resource extraction from tropical forests can arrange production and conservation to retain biodiversity and profits. This article is protected by copyright. All rights reserved

p53 missense but not truncation mutations are associated with low levels of p21CIP1/WAF1 mRNA expression in primary human sarcomas

Many growth-suppressing signals converge to control the levels of the CDK inhibitor p21CIP1/WAF1. Some human cancers exhibit low levels of expression of p21CIP1/WAF1and mutations in p53 have been implicated in this down-regulation. To evaluate whether the presence of p53 mutations was related to the in vivo expression of p21CIP1/WAF1 mRNA in sarcomas we measured the p21CIP1/WAF1 mRNA levels for a group of 71 primary bone and soft tissue tumours with known p53 status. As expected, most tumours with p53 mutations expressed low levels of p21CIP1/WAF1 mRNA. However, we identified a group of tumours with p53 gene mutations that exhibited normal or higher levels of p21CIP1/WAF1 mRNA. The p53 mutations in the latter group were not the common missense mutations in exons 4–9, but were predominantly nonsense mutations predicted to result in truncation of the p53 protein. The results of this study suggest that different types of p53 mutations can have different effects on the expression of downstream genes such as p21CIP1/WAF1 in human sarcomas. © 2001 Cancer Research Campaign http://www.bjcancer.co

Environmental incomes and rural livelihoods : a global-comparative assessment

Various case studies have suggested that environmental incomes from forests and other vegetation types are important for rural households in developing countries. However, in most large-scale household surveys these income sources are either underreported or ignored, hence there has been a lack of evidence to support the wider applicability of that claim. This paper reports data from the Poverty Environment Network (PEN), which has gathered comparable income data from about 8,000 households in 360 villages and 58 sites, spread over 24 developing countries. The data collection involved a careful, quarterly recording of all forest and environmental uses, as well as other major income sources over one full year. We find that forest income on average constitutes about one fifth of total household income, while adding other environmental income brings the share to more than one fourth – about the same as incomes from growing crops. Environmental resources and agricultural crops are the two main sources of livelihoods in the survey sites. As expected, forest reliance (share of forest income in total household income) is higher for the poorer income quintiles, but the differences are less pronounced than what was found in most previous studies. We also find that safety net and seasonal gap-filling functions may be less important that often assumed. Ignoring environmental incomes in income surveys and in rural development planning would in quantitative terms amount to ignoring that farmers grow crops. Agricultural area expansion into forests and other vegetation types may well come to increase household incomes, but corresponding income losses from losing forest cover and forest degradation could be larger than previously assumed. Depriving poor people of access to forest product extraction, for instance through highly exclusionary conservation policies, could jeopardize the livelihoods of people depending on these resources

Albumin-coupled methotrexate (MTX-HSA) is a new anti-arthritic drug which acts synergistically to MTX

Objective. To evaluate the anti-arthritic effects of the new inflammation-targeted drug MTX-HSA and to investigate whether peripheral blood mononuclear cells (PBMC) are potential target cells for albumin-mediated drug delivery. Methods. The murine model of collagen-induced arthritis (CIA) was used to measure the anti-arthritic effect of MTX, MTX-HSA or a combination of both (n = 30 to 35 per group). In addition, the uptake of fluorescence-labelled albumin (AFLc-HSA) in PBMC of 14 patients with RA was measured by fluorescence-activated cell sorting (FACS). Results. In equivalent doses of 7.5 mg/kg intravenously (IV) twice a week, MTX-HSA is significantly (P<0.02) superior to MTX in inhibiting the development of CIA and reducing the joint count as well as the number of affected paws. When given in lower doses as combination therapy, both drugs act synergistically (P<0.03). A mean of 96, 72 and 64% of the CD14-, CD16- and CD20-positive cells from peripheral blood of rheumatoid arthritis (RA) patients showed an uptake of albumin after incubation with AFLc-HSA in vitro. This finding was not significantly different in comparison to healthy controls. In contrast, the number of CD3-positive cells taking up albumin is increased significantly in RA patients in comparison to controls (26.3 ± 12.9% s.d. vs 11.6 ± 7.3% s.d.; P = 0.005). Conclusion. The data show that the effectiveness of MTX-HSA in CIA is superior to MTX and that both drugs act synergistically. In addition, albumin appears to be taken up by peripheral blood cells, suggesting that they might be one of the potential target cells of this novel anti-arthritic treatment approac

Passive room conditioning using phase change materials—Demonstration of a long-term real size experiment

The thermal properties of lightweight buildings can be efficiently improved by using phase change materials (PCMs). The heat storage capacity of the building can be extended exactly at the desired temperature level, which leads to an enormous increase in residential comfort. This is shown in the present paper using the example of a prefabricated wooden house. The house was divided into two identical rooms. One of them was equipped with almost one ton of phase change material based on salt hydrates with a melting temperature of approx. 21°C. The material was encapsulated in 1-l Polyethylene containers and installed in two back-ventilated layers inside of the walls. The house was monitored for a period of 87 days in terms of temperatures, solar radiation and air velocity inside the PCM wall system. A considerable temperature buffering could be observed in the PCM room compared to the reference room. An overall reduction of the temperature fluctuations of 57% and a reduction of the day/night fluctuations of 62% compared to the reference room could be obtained. In addition, a prediction regarding the energy demand of such buildings is discussed on the basis of a simulation program. Thus, the annual cooling capacity can be reduced by 36.5% compared to the regular timber construction technique by introducing PCM. Furthermore, the good correlation of the simulation results with the experimental ones allows using the simulation as a tool to design a house with additional thermal storages