Kinetic Investigation of Polyurethane Rubber Formation from CO2‐Containing Polyols

A novel CO2 utilization technology allows for the inclusion of CO2 as carbonate units and double bond moieties to give additional functionality in polyether polyols. This study examines the chain‐elongation kinetics of these diols with diisocyanates to polyurethane rubbers by means of thermal analysis. A reaction order of 1 indicates a strong influence of the chains' mobility on the reaction rate. Spectrometry and comparison with non‐double‐bond polyols reveal that the effect cannot be attributed to a substantial occurrence of side reactions but is rather due to the intertwining of lengthy chains.BMBF, 033R350A‐D, Production DreamsTU Berlin, Open-Access-Mittel - 202

On Recurrent Reachability for Continuous Linear Dynamical Systems

The continuous evolution of a wide variety of systems, including continuous-time Markov chains and linear hybrid automata, can be described in terms of linear differential equations. In this paper we study the decision problem of whether the solution $\boldsymbol{x}(t)$ of a system of linear differential equations $d\boldsymbol{x}/dt=A\boldsymbol{x}$ reaches a target halfspace infinitely often. This recurrent reachability problem can equivalently be formulated as the following Infinite Zeros Problem: does a real-valued function $f:\mathbb{R}_{\geq 0}\rightarrow\mathbb{R}$ satisfying a given linear differential equation have infinitely many zeros? Our main decidability result is that if the differential equation has order at most $7$, then the Infinite Zeros Problem is decidable. On the other hand, we show that a decision procedure for the Infinite Zeros Problem at order $9$ (and above) would entail a major breakthrough in Diophantine Approximation, specifically an algorithm for computing the Lagrange constants of arbitrary real algebraic numbers to arbitrary precision.Comment: Full version of paper at LICS'1

Prototyping Operational Autonomy for Space Traffic Management

Current state of the art in Space Traffic Management (STM) relies on a handful of providers for surveillance and collision prediction, and manual coordination between operators. Neither is scalable to support the expected 10x increase in spacecraft population in less than 10 years, nor does it support automated manuever planning. We present a software prototype of an STM architecture based on open Application Programming Interfaces (APIs), drawing on previous work by NASA to develop an architecture for low-altitude Unmanned Aerial System Traffic Management. The STM architecture is designed to provide structure to the interactions between spacecraft operators, various regulatory bodies, and service suppliers, while maintaining flexibility of these interactions and the ability for new market participants to enter easily. Autonomy is an indispensable part of the proposed architecture in enabling efficient data sharing, coordination between STM participants and safe flight operations. Examples of autonomy within STM include syncing multiple non-authoritative catalogs of resident space objects, or determining which spacecraft maneuvers when preventing impending conjunctions between multiple spacecraft. The STM prototype is based on modern micro-service architecture adhering to OpenAPI standards and deployed in industry standard Docker containers, facilitating easy communication between different participants or services. The system architecture is designed to facilitate adding and replacing services with minimal disruption. We have implemented some example participant services (e.g. a space situational awareness provider/SSA, a conjunction assessment supplier/CAS, an automated maneuver advisor/AMA) within the prototype. Different services, with creative algorithms folded into then, can fulfil similar functional roles within the STM architecture by flexibly connecting to it using pre-defined APIs and data models, thereby lowering the barrier to entry of new players in the STM marketplace. We demonstrate the STM prototype on a multiple conjunction scenario with multiple maneuverable spacecraft, where an example CAS and AMA can recommend optimal maneuvers to the spacecraft operators, based on a predefined reward function. Such tools can intelligently search the space of potential collision avoidance maneuvers with varying parameters like lead time and propellant usage, optimize a customized reward function, and be implemented as a scheduling service within the STM architecture. The case study shows an example of autonomous maneuver planning is possible using the API-based framework. As satellite populations and predicted conjunctions increase, an STM architecture can facilitate seamless information exchange related to collision prediction and mitigation among various service applications on different platforms and servers. The availability of such an STM network also opens up new research topics on satellite maneuver planning, scheduling and negotiation across disjoint entities

Effect of psychiatry liaison with general practitioners on depression severity in recently hospitalised cardiac patients: a randomised controlled trial

The document attached has been archived with permission from the editor of the Medical Journal of Australia (26 April 2007). An external link to the publisher’s copy is included.Objective: To evaluate the effect on depressive symptoms in cardiac patients of patient-specific advice to general practitioners regarding management of comorbid depression. Design and setting: A randomised controlled trial in four general hospitals in Adelaide, South Australia. Participants: Patients (n = 669) admitted to cardiology units for a range of cardiovascular conditions who were screened and assessed as being depressed according to the Center for Epidemiological Studies Depression Scale (CES-D). Intervention: Inpatient psychiatric review, followed by telephone case conferencing between specialist hospital staff and GPs to provide patient-specific information about the patient’s depression and its management, educational material, and ongoing clinical support. Main outcome measures: Level of depression severity at 12 months posthospitalisation. Results: On the basis of intention to treat, intervention patients had lower rates of moderate to severe depression (CES-D ≥ 27) after 12 months (25% v 35%, relative risk, 0.72; 95% CI, 0.54–0.96, number needed to treat for benefit, 11). The intervention was most effective in preventing progression from mild depression to moderate to severe depression. The multidisciplinary telephone case conferencing was difficult to implement and, in a post hoc analysis, brief phone advice from a psychiatrist was found to be effective. Conclusions: Screening hospitalised cardiac patients for depression and providing targeted advice to their GPs reduces depression severity 12 months after hospitalisation.Geoff Schrader, Frida Cheok, Ann-Louise Hordacre, Julie Marker and Victoria Wad

Depression after cardiac hospitalisation: the identifying depression as a comorbid condition (IDACC) study

Copyright © 2005 Royal Australian College of General Practitioners Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.Background: The Identifying Depression as a Comorbid Condition (IDACC) study aimed to identify depressive symptoms in hospitalised cardiac patients and support management of depression in general practice. Objective: This post hoc analysis of the IDACC trial examines the effectiveness and practicality of different forms of communication between hospital psychiatric services and general practitioners. Methods: We randomised 669 cardiac inpatients with depressive symptoms, identified with the Center for Epidemiological Studies Depression Scale (CES-D), to an intervention or usual care control group. Individual depression scores and depression management guidelines were sent to GPs of all intervention patients. Where possible, psychiatric advice was provided to the GP either by multidisciplinary enhanced primary care case conference or one-to-one telephone advice. Results: Multidisciplinary case conferences were implemented for only 24% of intervention patients. General practitioners received individual telephone advice in 40% of cases, and 36% received written information only. The psychiatrist telephone advice resulted in a significant reduction in the proportion of patients with moderate to severe depression 12 months after cardiac hospitalisation (19% vs. 35%). Discussion: Screening, combined with psychiatrist telephone advice to GPs, was simple to organise and effective in reducing depression severity after cardiac admission.Victoria Wade, Frida Cheok, Geoff Schrader, Ann-Louise Hordacre and Julie Marke

Depression after cardiac hospitalisation: the identifying depression as a comorbid condition (IDACC) study

Copyright © 2005 Royal Australian College of General Practitioners Copyright to Australian Family Physician. Reproduced with permission. Permission to reproduce must be sought from the publisher, The Royal Australian College of General Practitioners.Background: The Identifying Depression as a Comorbid Condition (IDACC) study aimed to identify depressive symptoms in hospitalised cardiac patients and support management of depression in general practice. Objective: This post hoc analysis of the IDACC trial examines the effectiveness and practicality of different forms of communication between hospital psychiatric services and general practitioners. Methods: We randomised 669 cardiac inpatients with depressive symptoms, identified with the Center for Epidemiological Studies Depression Scale (CES-D), to an intervention or usual care control group. Individual depression scores and depression management guidelines were sent to GPs of all intervention patients. Where possible, psychiatric advice was provided to the GP either by multidisciplinary enhanced primary care case conference or one-to-one telephone advice. Results: Multidisciplinary case conferences were implemented for only 24% of intervention patients. General practitioners received individual telephone advice in 40% of cases, and 36% received written information only. The psychiatrist telephone advice resulted in a significant reduction in the proportion of patients with moderate to severe depression 12 months after cardiac hospitalisation (19% vs. 35%). Discussion: Screening, combined with psychiatrist telephone advice to GPs, was simple to organise and effective in reducing depression severity after cardiac admission.Victoria Wade, Frida Cheok, Geoff Schrader, Ann-Louise Hordacre and Julie Marke

Splitting fields and general differential Galois theory

An algebraic technique is presented that does not use results of model theory and makes it possible to construct a general Galois theory of arbitrary nonlinear systems of partial differential equations. The algebraic technique is based on the search for prime differential ideals of special form in tensor products of differential rings. The main results demonstrating the work of the technique obtained are the theorem on the constructedness of the differential closure and the general theorem on the Galois correspondence for normal extensions..Comment: 33 pages, this version coincides with the published on

Tameness of holomorphic closure dimension in a semialgebraic set

Given a semianalytic set S in a complex space and a point p in S, there is a unique smallest complex-analytic germ at p which contains the germ of S, called the holomorphic closure of S at p. We show that if S is semialgebraic then its holomorphic closure is a Nash germ, for every p, and S admits a semialgebraic filtration by the holomorphic closure dimension. As a consequence, every semialgebraic subset of a complex vector space admits a semialgebraic stratification into CR manifolds satisfying a strong version of the condition of the frontier.Comment: Published versio