Early Warning Signals for Critical Transitions: A Generalized Modeling Approach

Critical transitions are sudden, often irreversible, changes that can occur in a large variety of complex systems; signals that warn of critical transitions are therefore highly desirable. We propose a new method for early warning signals that integrates multiple sources of information and data about the system through the framework of a generalized model. We demonstrate our proposed approach through several examples, including a previously published fisheries model. We regard our method as complementary to existing early warning signals, taking an approach of intermediate complexity between model-free approaches and fully parameterized simulations. One potential advantage of our approach is that, under appropriate conditions, it may reduce the amount of time series data required for a robust early warning signal

Lack of evidence of disease contamination in ovarian tissue harvested for cryopreservation from patients with Hodgkin lymphoma and analysis of factors predictive of oocyte yield

Ovarian cryopreservation is a promising technique to preserve fertility in women with Hodgkin lymphoma (HL) treated with chemotherapy. Thus, the aim of this study was to examine harvested ovarian tissue for subclinical involvement by HL by morphology/immunohistochemistry, and to define patient and treatment factors predictive of oocyte yield. This was a retrospective analysis of 26 ovarian tissue samples harvested for cryopreservation from women with HL. Histology, immunohistochemistry and follicle density (number mm−3) was examined. Disease status and preharvest chemotherapy details were obtained on 24 patients. The median age was 22 years (range 13–29). Seven of 24 patients had infradiaphragmatic disease at time of harvest. Nine of 20 patients had received chemotherapy preharvest (ABVD (Adriamycin®, Bleomycin, Vinblastine and Dacarbazine)=7, other regimens=2). The seven receiving ABVD showed no difference in follicle density compared to patients not receiving treatment (n=14); (median=1555 vs 1620 mm3 P=0.97). Follicle density measurement showed no correlation with patient age (R2=0.0001, P=0.99). There was no evidence of HL involvement in the 26 samples examined (95% CI=0–11%). In conclusion, subclinical involvement of HL has not been identified in ovarian tissue, even when patients have infradiaphragmatic disease. Furthermore, the quality of tissue harvested does not appear to be adversely affected by patient's age or prior ABVD chemotherapy

Strategies for tropical forest protection and sustainable supply chains: challenges and opportunities for alignment with the UN sustainable development goals

Governance for sustainable development increasingly involves diverse stakeholder groups, with the promise of enhanced legitimacy and effectiveness in decision-making and implementation. The UN sustainable development goals (SDGs) emphasise the important role of multiple (non-state) actors, including businesses and non-governmental organisations, including in efforts to ensure the sustainability of supply chains, and to reduce tropical deforestation and forest degradation. This paper critically analyses sustainability strategies to examine how the UN SDG agendas related to ‘sustainable supply chains’ and ‘tropical forest protection’ are framed and enacted by two contrasting non-state actors: (1) Instituto Centro de Vida (ICV), an NGO in Brazil working to address deforestation, including by supporting farmers to produce commodities, and (2) Unilever, a global consumer goods manufacturer and major buyer of such commodities. By identifying areas of variability in the discursive techniques used by ICV and Unilever, we unearth particular power dynamics that can shape the processes and outcomes of sustainability strategies. This paper finds that the two organisations use diverse strategies at different levels of governance, both participate actively in multi-stakeholder forums to advance their organisations’ goals, but have divergent framings of ‘sustainability’. Despite being considered ‘non-state’ actors, the strategies of the two organisations examined both reflect, and influence, the structural effects of the state in the implementation of non-state organisations’ strategies, and progress towards the SDGs. Although there is alignment of certain strategies related to tropical forest protection, in some cases, there is a risk that more sustainable, alternative approaches to governing forests and supply chains may be excluded

Numerical analysis of different heating systems for warm sheet metal forming

The main goal of this study is to present an analysis of different heating methods frequently used in laboratory scale and in the industrial practice to heat blanks at warm temperatures. In this context, the blank can be heated inside the forming tools (internal method) or using a heating system (external method). In order to perform this analysis, a finite element model is firstly validated with the simulation of the direct resistance system used in a Gleeble testing machine. The predicted temperature was compared with the temperature distribution recorded experimentally and a good agreement was found. Afterwards, a finite element model is used to predict the temperature distribution in the blank during the heating process, when using different heating methods. The analysis also includes the evaluation of a cooling phase associated to the transport phase for the external heating methods. The results of this analysis show that neglecting the heating phase and a transport phase could lead to inaccuracies in the simulation of the forming phase.The authors gratefully acknowledge the financial support of the Portuguese Foundation for Science and Technology (FCT) under project PTDC/EMS-TEC/1805/2012 and by FEDER funds through the program COMPETE—Programa Operacional Factores de Competitividade, under the project CENTRO-07-0224-FEDER-002001 (MT4MOBI). The authors would like to thank Prof. A. Andrade-Campos for helpful contributions on the development of the finite element code presented in this work.info:eu-repo/semantics/publishedVersio

Endothelial nitric oxide synthase gene polymorphism (Glu298Asp) and development of pre-eclampsia: a case-control study and a meta-analysis

BACKGROUND: Pre-eclampsia is thought to have an important genetic component. Recently, pre-eclampsia has been associated in some studies with carriage of a common eNOS gene Glu298Asp polymorphism, a variant that leads to the replacement of glutamic acid by aspartic acid at codon 298. METHOD: Healthy women with singleton pregnancies were recruited from 7 district general hospitals in London, UK. Women at high risk of pre-eclampsia were screened by uterine artery Doppler velocimetry at 22–24 weeks of gestation and maternal blood was obtained to genotype the eNOS Glu298Asp polymorphism. Odds ratios (OR) and 95%CI, using logistic regression methods, were obtained to evaluate the association between the Glu298Asp polymorphism and pre-eclampsia. A meta-analysis was then undertaken of all published studies up to November 2005 examining the association of eNOS Glu298Asp genotype and pre-eclampsia. RESULTS: 89 women with pre-eclampsia and 349 controls were included in the new study. The Glu298Asp polymorphism in a recessive model was not significantly associated with pre-eclampsia (adjusted-OR: 0.83 [95%CI: 0.30–2.25]; p = 0.7). In the meta-analysis, under a recessive genetic model (1129 cases & 2384 controls) women homozygous for the Asp298 allele were not at significantly increased risk of pre-eclampsia (OR: 1.28 [95%CI: 0.76–2.16]; p = 0.34). A dominant model (1334 cases & 2894 controls) was associated with no increase of risk of pre-eclampsia for women carriers of the Asp298 allele (OR: 1.12 [95%CI: 0.84–1.49]; p = 0.42). CONCLUSION: From the data currently available, the eNOS Glu298Asp polymorphism is not associated with a significant increased risk of pre-eclampsia. However, published studies have been underpowered, much larger studies are needed to confirm or refute a realistic genotypic risk of disease, but which might contribute to many cases of pre-eclampsia in the population

Sfrp5 Modulates Both Wnt and BMP Signaling and Regulates Gastrointestinal Organogensis in the Zebrafish, Danio rerio

Sfrp5 belongs to the family of secreted frizzled related proteins (Sfrp), secreted inhibitors of Wingless-MMTV Integration Site (Wnt) signaling, which play an important role in cancer and development. We selected sfrp5 because of its compelling expression profile in the developing endoderm in zebrafish, Danio rerio. In this study, overexpression of sfrp5 in embryos results in defects in both convergent extension (CE) by inhibition of non-canonical Wnt signaling and defects in dorsoventral patterning by inhibition of Tolloid-mediated proteolysis of the BMP inhibitor Chordin. From 25 hours post fertilization (hpf) to 3 days post fertilization (dpf), both overexpression and knockdown of Sfrp5 decrease the size of the endoderm, significantly reducing liver cell number. At 3 dpf, insulin-positive endodermal cells fail to coalesce into a single pancreatic islet. We show that Sfrp5 inhibits both canonical and non-canonical Wnt signaling during embryonic and endodermal development, resulting in endodermal abnormalities. © 2013 Stuckenholz et al