Mixed volumes of networks with binomial steady-states

The steady-state degree of a chemical reaction network is the number of complex steady-states for generic rate constants and initial conditions. One way to bound the steady-state degree is through the mixed volume of the steady-state system or an equivalent system. In this work, we show that for partionable binomial networks, whose resulting steady-state systems are given by a set of binomials and a set of linear (not necessarily binomial) conservation equations, computing the mixed volume is equivalent to finding the volume of a single mixed cell that is the translate of a parallelotope. We then turn our attention to identifying cycles with binomial steady-state ideals. To this end, we give a coloring condition on directed cycles that guarantees the network has a binomial steady-state ideal. We highlight both of these theorems using a class of networks referred to as species-overlapping networks and give a formula for the mixed volume of these networks.Comment: 17 page

Evaluating the educational impact of pre- and post-visit activities on elementary students following a field trip to a public garden

Many public gardens offer tours to schoolchildren. Informal educators argue that preparing students for a field trip by providing pre- and post-visit activities can positively impact learning. However, there is little research that supports the efficacy of pre- and post-visit activities on learning at public gardens. Therefore, the purpose of this research was to determine the impact of pre- and post-visit activities on learning after a field trip to a public garden. This quasi-experimental study\u27s population included four fifth-grade classrooms assigned to one of two treatments: 1) a field trip only (control) and 2) a field trip with pre- and post-visit activities (treatment). A post-trip assessment consisted of open-ended questions and was scored quantitatively. Differences between treatment groups were analyzed by using a t-test. Findings indicated that there was no significant difference in post-test scores between the treatment groups. Although pre- and post-visit activities have been found to prepare students for a field trip and to tie the field trip to classroom learning, this case study did not show an increase in learning outcomes. A limitation of this research was the small number of students involved and should be conducted again with more students. However, the novel method of analysis may have implications for assessing what students learn on field trips to informal settings. This research has implications for informal education settings such as public gardens, botanical centers, and arboreta that seek to measure visitor learning

Impact of cyber-invasive species on a large ecological network

As impacts of introduced species cascade through trophic levels, they can cause indirect and counter-intuitive effects. To investigate the impact of invasive species at the network scale, we use a generalized food web model, capable of propagating changes through networks with a series of ecologically realistic criteria. Using data from a small British offshore island, we quantify the impacts of four virtual invasive species (an insectivore, a herbivore, a carnivore and an omnivore whose diet is based on a rat) and explore which clusters of species react in similar ways. We find that the predictions for the impacts of invasive species are ecologically plausible, even in large networks. Species in the same taxonomic group are similarly impacted by a virtual invasive species. However, interesting differences within a given taxonomic group can occur. The results suggest that some native species may be at risk from a wider range of invasives than previously believed. The implications of these results for ecologists and land managers are discussed

The absence of myocardial calcium-independent phospholipase a2γ results in impaired prostaglandin e2 production and decreased survival in mice with acute trypanosoma cruzi infection

Cardiomyopathy is a serious complication of Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi. The parasite often infects cardiac myocytes, causing the release of inflammatory mediators, including eicosanoids. A recent study from our laboratory demonstrated that calcium-independent phospholipase A(2)γ (iPLA(2)γ) accounts for the majority of PLA(2) activity in rabbit ventricular myocytes and is responsible for arachidonic acid (AA) and prostaglandin E(2) (PGE(2)) release. Thus, we hypothesized that cardiac iPLA(2)γ contributes to eicosanoid production in T. cruzi infection. Inhibition of the isoform iPLA(2)γ or iPLA(2)β, with the R or S enantiomer of bromoenol lactone (BEL), respectively, demonstrated that iPLA(2)γ is the predominant isoform in immortalized mouse cardiac myocytes (HL-1 cells). Stimulation of HL-1 cells with thrombin, a serine protease associated with microthrombus formation in Chagas' disease and a known activator of iPLA(2), increased AA and PGE(2) release, accompanied by platelet-activating factor (PAF) production. Similarly, T. cruzi infection resulted in increased AA and PGE(2) release over time that was inhibited by pretreatment with (R)-BEL. Further, T. cruzi-infected iPLA(2)γ-knockout (KO) mice had lower survival rates and increased tissue parasitism compared to wild-type (WT) mice, suggesting that iPLA(2)γ-KO mice were more susceptible to infection than WT mice. A significant increase in iPLA(2) activity was observed in WT mice following infection, whereas iPLA(2)γ-KO mice showed no alteration in cardiac iPLA(2) activity and produced less PGE(2). In summary, these studies demonstrate that T. cruzi infection activates cardiac myocyte iPLA(2)γ, resulting in increased AA and PGE(2) release, mediators that may be essential for host survival during acute infection. Thus, these studies suggest that iPLA(2)γ plays a cardioprotective role during the acute stage of Chagas' disease

Analysis of Human Faces Using a Measurement-Based Skin Reflectance Model

We have measured 3D face geometry, skin reflectance, and subsurface scattering using custom-built devices for 149 subjects of varying age, gender, and race. We developed a novel skin reflectance model whose parameters can be estimated from measurements. The model decomposes the large amount of measured skin data into a spatially-varying analytic BRDF, a diffuse albedo map, and diffuse subsurface scattering. Our model is intuitive, physically plausible, and -- since we do not use the original measured data -- easy to edit as well. High-quality renderings come close to reproducing real photographs. The analysis of the model parameters for our sample population reveals variations according to subject age, gender, skin type, and external factors (e.g., sweat, cold, or makeup). Using our statistics, a user can edit the overall appearance of a face (e.g., changing skin type and age) or change small-scale features using texture synthesis (e.g., adding moles and freckles). We are making the collected statistics publicly available to the research community for applications in face synthesis and analysis.Engineering and Applied Science

Improving the organisation of maternal health service delivery and optimising childbirth by increasing vaginal birth after caesarean section through enhanced women-centred care (OptiBIRTH trial): study protocol for a randomised controlled trial (ISRCTN10612254)

Open Access JournalBackground The proportion of pregnant women who have a caesarean section shows a wide variation across Europe, and concern exists that these proportions are increasing. Much of the increase in caesarean sections in recent years is due to a cascade effect in which a woman who has had one caesarean section is much more likely to have one again if she has another baby. In some places, it has become common practice for a woman who has had a caesarean section to have this procedure again as a matter of routine. The alternative, vaginal birth after caesarean (VBAC), which has been widely recommended, results in fewer undesired results or complications and is the preferred option for most women. However, VBAC rates in some countries are much lower than in other countries. Methods/Design The OptiBIRTH trial uses a cluster randomised design to test a specially developed approach to try to improve the VBAC rate. It will attempt to increase VBAC rates from 25 % to 40 % through increased women-centred care and women’s involvement in their care. Sixteen hospitals in Germany, Ireland and Italy agreed to join the study, and each hospital was randomly allocated to be either an intervention or a control site. Discussion If the OptiBIRTH intervention succeeds in increasing VBAC rates, its application across Europe might avoid the 160,000 unnecessary caesarean sections that occur every year at an extra direct annual cost of more than €150 million

Health economic analysis of a cluster‐randomised trial (OptiBIRTH) designed to increase rates of vaginal birth after caesarean section

Der Artikel wurde innerhalb des EU-Projekts OptiBIRTH erstellt.This is the peer reviewed version of the following article: [Haunberger, S, Rüegger, C, Baumgartner, E. Experiences with a psychosocial screening instrument (S‐FIRST) to identify the psychosocial support needs of parents of children suffering from cancer. Psycho‐Oncology. 2019; 28: 1025‐ 1032.], which has been published in final form at https://doi.org/10.1002/pon.5045. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Objective: To perform a health economic analysis of an intervention designed to increase rates of vaginal birth after caesarean, compared with usual care. Design: Economic analysis alongside the cluster-randomised OptiBIRTH trial (Optimising childbirth by increasing vaginal birth after caesarean section (VBAC) through enhanced women-centred care). Setting: Fifteen maternity units in three European countries - Germany (five), Ireland (five), and Italy (five) - with relatively low VBAC rates. Population: Pregnant women with a history of one previous lower-segment caesarean section; sites were randomised (3:2) to intervention or control. Methods: A cost-utility analysis from both societal and health-services perspectives, using a decision tree. Main Outcome Measures: Costs and resource use per woman and infant were compared between the control and intervention group by country, from pregnancy recognition until 3 months postpartum. Based on the caesarean section rates, and maternal and neonatal morbidities and mortality, the incremental cost-utility ratios were calculated per country. Results: The mean difference in costs per quality-adjusted life years (QALYs) gained from a societal perspective between the intervention and the control group, using a probabilistic sensitivity analysis, was: €263 (95% CI €258-268) and 0.008 QALYs (95% CI 0.008-0.009 QALYs) for Germany, €456 (95% CI €448-464) and 0.052 QALYs (95% CI 0.051-0.053 QALYs) for Ireland, and €1174 (95% CI €1170-1178) and 0.006 QALYs (95% CI 0.005-0.007 QALYs) for Italy. The incremental cost-utility ratios were €33,741/QALY for Germany, €8785/QALY for Ireland, and €214,318/QALY for Italy, with a 51% probability of being cost-effective for Germany, 92% for Ireland, and 15% for Italy. Conclusion: The OptiBIRTH intervention was likely to be cost-effective in Ireland and Germany