Methodological and empirical progress and challenges in integrated assessment of agricultural systems and policies

In this contribution we first present a methodology for integrated assessment of agricultural systems (SEAMLESS Integrated Framework), illustrate its application in an integrated assessment of high commodity prices and then discuss its flexibility and limitations. From there we take a broader view and reflect on key scientific and empirical questions with respect to the development of research tools for the integrated assessment of agricultural systems.agricultural systems, integrated assessment, modelling, Agricultural and Food Policy, Farm Management,

Parametric Model Order Reduction of Port-Hamiltonian Systems by Matrix Interpolation

In this paper, parametric model order reduction of linear time-invariant systems by matrix interpolation is adapted to large-scale systems in port-Hamiltonian form. A new weighted matrix interpolation of locally reduced models is introduced in order to preserve the port-Hamiltonian structure, which guarantees the passivity and stability of the interpolated system. The performance of the new method is demonstrated by technical example

Decision-Tree Based Model Analysis for Efficient Identification of Parameter Relations Leading to Different Signaling States

In systems biology, a mathematical description of signal transduction processes is used to gain a more detailed mechanistic understanding of cellular signaling networks. Such models typically depend on a number of parameters that have different influence on the model behavior. Local sensitivity analysis is able to identify parameters that have the largest effect on signaling strength. Bifurcation analysis shows on which parameters a qualitative model response depends. Most methods for model analysis are intrinsically univariate. They typically cannot consider combinations of parameters since the search space for such analysis would be too large. This limitation is important since activation of a signaling pathway often relies on multiple rather than on single factors. Here, we present a novel method for model analysis that overcomes this limitation. As input to a model defined by a system of ordinary differential equations, we consider parameters for initial chemical species concentrations. The model is used to simulate the system response, which is then classified into pre-defined classes (e.g., active or not active). This is combined with a scan of the parameter space. Parameter sets leading to a certain system response are subjected to a decision tree algorithm, which learns conditions that lead to this response. We compare our method to two alternative multivariate approaches to model analysis: analytical solution for steady states combined with a parameter scan, and direct Lyapunov exponent (DLE) analysis. We use three previously published models including a model for EGF receptor internalization and two apoptosis models to demonstrate the power of our approach. Our method reproduces critical parameter relations previously obtained by both steady-state and DLE analysis while being more generally applicable and substantially less computationally expensive. The method can be used as a general tool to predict multivariate control strategies for pathway activation and to suggest strategies for drug intervention

Improving the Census Legal and Policy Reforms for a More Accurate, Equitable, and Legitimate Count

The census is a cornerstone of American democracy. The results of this constitutionally required, once-a-decade count of every person living in the United States dictate how seats in the House of Representatives are divided among the states, how state and local governments draw electoral districts, and how more than $1.5 trillion annually in federal funds is distributed for essential services such as health care, food assistance, and education. At its best, the census offers an authentic picture of who we are as a diverse and growing nation.The 2020 census struggled. It faced a barrage of obstacles, from executive interference to chronic underfunding to the Covid-19 pandemic. In the face of these challenges, it ultimately failed to reach 18.8 million people — more than 5 percent of the country's population. What's more, the census once again disproportionately undercounted people of color, with the Latino undercount rate more than tripling from the prior decade. And multiple states were undercounted by significant margins. These inaccuracies compromise the census's ability to fairly distribute political power and federal funding both across states and across communities, undercutting the democratic promise of our political system. Meanwhile, overall census response rates remain stuck in a rut, costs are rising, and the bureau's reliance on labor-intensive door-to-door outreach is showing its limits. The census is too critical to continue in this precarious state.This paper sets forth a blueprint for reforming the law and policy of the decennial population count. Our goal is to make future censuses more accurate, equitable, and legitimate. An accurate census correctly captures the number and demographic characteristics of all people residing in the country. An equitable census is designed, funded, and run to count all groups precisely and to distribute political power and economic support commensurate with each community's fair share. A legitimate census — one that is scientifically rigorous and democratically accountable and boasts universal participation — warrants and inspires widespread trust. Legitimacy and accuracy require equity; an equitable census is free from the long-running tendency to undercount Black, Latino, and Native American communities in comparison with white ones, inspiring confidence in its fundamental fairness

Integrable quadratic Hamiltonians on so(4) and so(3,1)

We investigate a special class of quadratic Hamiltonians on so(4) and so(3,1) and describe Hamiltonians that have additional polynomial integrals. One of the main results is a new integrable case with an integral of sixth degree.Comment: 16 page

Navigation in Curved Space-Time

A covariant and invariant theory of navigation in curved space-time with respect to electromagnetic beacons is written in terms of J. L. Synge's two-point invariant world function. Explicit equations are given for navigation in space-time in the vicinity of the Earth in Schwarzschild coordinates and in rotating coordinates. The restricted problem of determining an observer's coordinate time when their spatial position is known is also considered

Observational Comparison of Star Formation in Different Galaxy Types

Galaxies cover a wide range of masses and star formation histories. In this review, I summarize some of the evolutionary key features of common galaxy types. At the high-mass end, very rapid, efficient early star formation is observed, accompanied by strong enrichment and later quiescence, well-described by downsizing scenarios. In the intermediate-mass regime, early-type galaxies may still show activity in low-mass environments or when being rejuvenated by wet mergers. In late-type galaxies, we find continuous, though variable star formation over a Hubble time. In the dwarf regime, a wide range of properties from bursty activity to quiescence is observed. Generally, stochasticity dominates here, and star formation rates and efficiencies tend to be low. Morphological types and their star formation properties correlate with environment.Comment: Invited review to appear in IAU Symposium 270 on "Computational Star Formation". Editors: J. Alves, B.G. Elmegreen, J.M. Girart, and V. Trimble (Cambridge University Press). 12 pages, no figure

Dust heating by the interstellar radiation field in models of turbulent molecular clouds

We have calculated the radiation field, dust grain temperatures, and far infrared emissivity of numerical models of turbulent molecular clouds. When compared to a uniform cloud of the same mean optical depth, most of the volume inside the turbulent cloud is brighter, but most of the mass is darker. There is little mean attenuation from center to edge, and clumping causes the radiation field to be somewhat bluer. There is also a large dispersion, typically by a few orders of magnitude, of all quantities relative to their means. However, despite the scatter, the 850 micron emission maps are well correlated with surface density. The fraction of mass as a function of intensity can be reproduced by a simple hierarchical model of density structure.Comment: 32 pages, 14 figures, submitted to Ap

Barriers to seeking emergency care during the COVID-19 pandemic may lead to higher morbidity and mortality – a retrospective study from a Swiss university hospital

AIMS OF THE STUDY While COVID-19 significantly overburdens emergency rooms (ERs) and hospitals in affected areas, ERs elsewhere report a marked decrease in patient numbers. This study aimed to investigate the assumption that patients with urgent problems currently avoid the ER. METHODS Electronic health records from the ER of a large Swiss university hospital were extracted for three periods: first, the awareness phase (ap) from the publication of the national government’s initiative “How to protect ourselves” on 1 March 2020 to the lockdown of the country on 16 March; second, the mitigation phase (mp) from 16–30 March; finally, patients presenting in March 2019 were used as a control group. We compared parameters including a critical illness as the discharge diagnosis (e.g., myocardial infarction, stroke, sepsis and ER death) using logistic and linear regression, as well as 15-day bootstrapped means and 95% confidence intervals for the control group. RESULTS In the three periods, a total of 7143 patients were treated. We found a 24.9% (42.5%) significant decline in the number of patients presenting during the ap (mp). Patients presenting during the mp were more likely to be critically ill. There was an increase of 233% and 367% (ap and mp, respectively) of ER deaths (none related to COVID-19) compared to the control period. Apart from polytrauma (increase of 5% in the mp), all other critical illnesses as discharge diagnosis showed a lower incidence in descriptive analysis. Significantly more patients died in the ER in both the ap and mp. CONCLUSIONS Barriers to seeking emergency care during COVID-19 pandemic may lead to higher morbidity and mortality. Healthcare authorities and hospitals must ensure low barriers to treatment and business as usual for all patients