Scheduling non-urgent patient transportation while maximizing emergency coverage

Many ambulance providers operate both advanced life support (ALS) and basic life support (BLS) ambulances. Typically, only an ALS ambulance can respond to an emergency call, whereas non-urgent patient transportation requests can be served by either an ALS or a BLS ambulance. The total capacity of BLS ambulances is usually not enough to fulfill all non-urgent transportation requests. The remaining transportation requests then have to be performed by ALS ambulances, which reduces the coverage for emergency calls. We present a model that determines the routes for BLS ambulances while maximizing the remaining coverage by ALS ambulances. Different from the classical dial-a-ride problem, only one patient can be transported at a time, and not all requests are known in advance. Throughout the day, new requests arrive, and we present an online model to deal with these requests

Scheduling non-urgent patient transportation while maximizing emergency coverage

Many ambulance providers operate both advanced life support (ALS) and basic life support (BLS) ambulances. Typically, only an ALS ambulance can respond to an emergency call, whereas non-urgent patient transportation requests can either be served by an ALS or a BLS ambulance. The total capacity of BLS ambulances is usually not enough to fulfill all non-urgent transportation requests. The remaining transportation requests then have to be performed by ALS ambulances, which reduces the coverage for emergency calls. We present a model that determines the routes for BLS ambulances while maximizing the remaining coverage by ALS ambulances. Different from the classical Dial-A-Ride Problem, only one patient can be transported at a time and not all request are known in advance. Throughout the day, new requests arrive and we present an online model to deal with these requests

Geleide N-bemesting voor aardappelen op basis van gewasreflectie-metingen : integratie van sensormetingen in een N-bijmestsysteem

Voor aardappelen zijn er nog geen regels die een sensormeting om kunnen zetten naar een N-advies. Het doel van het in dit rapport beschreven onderzoek is (1) het ontwikkelen van een ijklijn om de N-inhoud van het gewas aan de hand van reflectiemetingen te kunnen bepalen, en (2) het ontwikkelen van adviesregels om de bijmestgift vast te stellen aan de hand van de gemeten N-inhoud van het gewas. Onder leiding van Remmie Booij werd in de periode 1996-2003 een op gewasreflectiemetingen gebaseerd N-bijmestsysteem voor aardappelen ontwikkeld. Dit systeem is nooit gedocumenteerd en is daarom opnieuw uit de originele onderzoeksgegevens afgeleid. De resultaten zijn (1) de N-inhoud van een aardappelgewas kan voldoende nauwkeurig bepaald worden met een meting van de gewasreflectie, (2) wachten met bijmesten tot de bodembedekking minimaal 90% bedraagt, resulteert niet in een lagere opbrengst terwijl wel N wordt bespaard, en (3) de grootte van de bijmestgift kan worden bepaald door een streefwaarde voor de N-inhoud te verminderen met de gemeten N-inhoud. In dit rapport wordt een praktische handleiding gegeven aan de hand waarvan de teler systeem-Booij kan uitvoeren

Closed geodesics in Alexandrov spaces of curvature bounded from above

In this paper, we show a local energy convexity of $W^{1,2}$ maps into $CAT(K)$ spaces. This energy convexity allows us to extend Colding and Minicozzi's width-sweepout construction to produce closed geodesics in any closed Alexandrov space of curvature bounded from above, which also provides a generalized version of the Birkhoff-Lyusternik theorem on the existence of non-trivial closed geodesics in the Alexandrov setting.Comment: Final version, 22 pages, 2 figures, to appear in the Journal of Geometric Analysi

Design of a periodic counter-current chromatography process for efficient oncolytic virus purification

Virus-based biologicals are one of the most promising biopharmaceuticals of the 21st century medicine and play a significant role in the development of innovative therapeutic, prophylactic and clinical applications. These biologicals share between them a high degree of complexity and offer various challenges requiring innovative technologies for their manufacturing. Oncolytic virus manufacturing scale can range from 5L in research and development up to 50L for clinical studies and reach hundreds of liters for commercial scale. The inehrent productivity and high integration potential of periodic counter-current chromatography offers a transversal solution to decrease equipment footprint and the reduction of several non-value-added unit operations. The work to be reported focus on the design of a periodic counter-current chromatography process applied to the intermediate purification of oncolytic adenovirus. Moving away from single-column batch operation towards continuous or semi-continuous, multi-column chromatography creates the opportunity to benefit from synergies of solvent gradients, recycling chromatography, and simulated counter-current movement of the adsorbent and fluid phases, providing substantial reductions in chromatographic resin volume and buffer consumption. The developed ion exchange chromatographic purification method was carried out using a four-column setup, supported by mechanistic mathematical modeling. Obtained virus recoveries (\u3e 60%) and impurity reductions (\u3e 80% DNA, and \u3e 70% total protein) match or overcome batch purification. The impact of column cycling on column capacity will be presented and the steps taken to minimize it will be discussed, highlighting the optimization of the cleaning-in-place step and the need to include organic solvents to promote the stripping of tighter-adsorbing impurities. Moreover, the robustness of the dynamic control strategy and its ability to overcome perturbations originated in precedent stages will be demonstrated using feeds with different impurity profiles and titers, showing that it is possible to generate elution pools with consistent quality and traceability. Additionally, due to the wealth of data generated through the cycling operations, such as historic columns breakthrough and elution peak profiles, a deeper insight on product quality and process knowledge is gained. Moreover, process automation enables the minimization of errors, maximizing process efficiency, uptime, repeatability, and process replication

Outlets of 2D invasion percolation and multiple-armed incipient infinite clusters

We study invasion percolation in two dimensions, focusing on properties of the outlets of the invasion and their relation to critical percolation and to incipient infinite clusters (IIC's). First we compute the exact decay rate of the distribution of both the weight of the kth outlet and the volume of the kth pond. Next we prove bounds for all moments of the distribution of the number of outlets in an annulus. This result leads to almost sure bounds for the number of outlets in a box B(2^n) and for the decay rate of the weight of the kth outlet to p_c. We then prove existence of multiple-armed IIC measures for any number of arms and for any color sequence which is alternating or monochromatic. We use these measures to study the invaded region near outlets and near edges in the invasion backbone far from the origin.Comment: 38 pages, 10 figures, added a thorough sketch of the proof of existence of IIC's with alternating or monochromatic arms (with some generalizations

Septal ablation in hypertrophic obstructive cardiomyopathy improves systolic myocardial function in the lateral (free wall): a follow-up study using CMR tissue tagging and 3D strain analysis

Aims: Alcohol septal ablation (ASA) has been successful in the treatment of symptomatic hypertrophic obstructive cardiomyopathy (HOCM). The aim of this study is to evaluate the effects of ethanol-induced myocardial infarcts on regional myocardial function using cardiac magnetic resonance (CMR) tissue tagging and 3-dimensional (3D) strain analysis. Methods and results: In nine patients (age 52±15 years) who underwent ASA, CMR was performed prior to and 6 months after the procedure. Regional myocardial mass was evaluated using cine imaging. Myocardial tagging was used to calculate systolic 3D myocardial strain values. These strain values were used to calculate the shortening index (SI), a robust parameter for myocardial contraction. Maximum end-systolic (ES) SI and systolic SI rate were quantified in three circumferential segments: septum, adjacent, and remote (lateral) myocardium. Compared with baseline, septal and non-septal mass decreased at follow-up (from 72±27 to 59±21 g; P=0.008 and from 131±34 to 109±30 g; P=0.008, respectively). In the septum, maximum ES SI and SI rate remained unchanged after ASA. In adjacent myocardium, ES SI remained unchanged, whereas SI rate improved (from -56.5±21.1 to -70.0±16.7%/s; P=0.02). Both ES SI and SI rate improved significantly in remote myocardium (from -16.9±2.8 to -18.8±3.2%; P=0.02 and from -70.3±9.2 to -86.1±15.0%/s; P=0.01, respectively). Conclusion: Reduction of left ventricular (LV) outflow tract obstruction in symptomatic HOCM is associated with a significant reduction in myocardial mass and improvement of intramural systolic function in the lateral (remote) wall, indicating reversed LV remodelling. © The European Society of Cardiology 2006. All rights reserved

Comparing population and incident data for optimal air ambulance base locations in Norway

Background: Helicopter emergency medical services are important in many health care systems. Norway has a nationwide physician manned air ambulance service servicing a country with large geographical variations in population density and incident frequencies. The aim of the study was to compare optimal air ambulance base locations using both population and incident data. Methods: We used municipality population and incident data for Norway from 2015. The 428 municipalities had a median (5-95 percentile) of 4675 (940-36,264) inhabitants and 10 (2-38) incidents. Optimal helicopter base locations were estimated using the Maximal Covering Location Problem (MCLP) optimization model, exploring the number and location of bases needed to cover various fractions of the population for time thresholds 30 and 45 min, in green field scenarios and conditioned on the existing base structure. Results: The existing bases covered 96.90% of the population and 91.86% of the incidents for time threshold 45 min. Correlation between municipality population and incident frequencies was -0.0027, and optimal base locations varied markedly between the two data types, particularly when lowering the target time. The optimal solution using population density data put focus on the greater Oslo area, where one third of Norwegians live, while using incident data put focus on low population high incident areas, such as northern Norway and winter sport resorts. Conclusion: Using population density data as a proxy for incident frequency is not recommended, as the two data types lead to different optimal base locations. Lowering the target time increases the sensitivity to choice of data

Gastrointestinal Symptoms in Infants of Mothers with a Psychiatric History and the Role of Depression and Bonding

Objectives: Gastroesophageal reflux (GER), excessive crying, and constipation are common gastrointestinal symptoms in infancy of multifactorial origin in which psychosocial stress factors play an important role. The aims of this observational study were to investigate the presence of gastrointestinal symptoms in infants of mothers with or without a history of a psychiatric disorder, their association with maternal depressive symptoms, and the possible mediating role of bonding. Methods: 101 mothers with a history of a psychiatric disorder (“PD mothers”) and 60 control mothers were included. Infant gastrointestinal symptoms, maternal depressive symptoms, and mother-infant bonding were assessed using validated questionnaires and diagnostic criteria at 1.5 month postpartum. Results: The mean total score on the Infant Gastroesophageal Reflux Questionnaire Revised (I-GERQ-R) reported in infants of PD mothers (13.4 SD 5.4) was significantly higher than in infants of control mothers (10.8 SD 5.4; P =.003). No significant differences were found in the presence of excessive crying (modified Wessel’s criteria and subjective experience) and constipation (ROME IV criteria) between both groups. Infant GER was associated with maternal depressive symptoms (P = 0.027) and bonding problems (P = <0.001). Constipation was related to maternal depressive symptoms (P = 0.045), and excessive crying (Wessel and subjective criteria) was associated with bonding problems (respectively P = 0.022 and P = 0.002). The effect of maternal depressive symptomatology on infant GER symptoms and excessive crying was mediated by bonding problems. Conclusion: Maternal psychiatric history is associated with infant gastrointestinal symptoms, in which mother-infant bonding is a mediating factor