Making Pigs Fly

[Excerpt] You\u27ll see a union in this hospital when pigs fly. So went the opening statement by the new Vice President of Human Resources at St. Joseph Medical Center in Joliet, Illinois. Poor staffing ratios, out-dated equipment, lack of respect and nonexistent communications between staff and management compelled the nurses of St. Joe\u27s to bring in the Illinois Nurses Association in February, 1991. Fifteen years earlier, the nurses had tried to organize a union but had lost the election. Ironically, the issues were the same — nothing had changed. The odds still appeared to be against the nurses. St. Joe\u27s management hired the notorious law firm Seyfarth, Shaw, Fairweather and Geraldson and two anti-union consultants, Modern Management, Inc. and Management Science Associates. They forced the nurses out on strike for 61 days in the dead of winter, and tried to use a Colorado-based scab nursing agency, U.S. Nursing, to bring in replacements. This time, however, the outcome was different. On March 16, 1993, after the longest strike in Illinois nursing history, the St. Joe\u27s Nurses Association/INA signed their first contract with the medical center. Had it not been for the overwhelming community support, built over the months of organizing and negotiating, there is little chance that we would have won our struggle for a union. We gained support not only because our cause was just, but because we had strong primary and secondary leadership in the union and a communication network which reached every St. Joe\u27s nurse. We took these same strengths and skills and applied them in the public arena. Anti-union management, union-busting lawyers and consultants could not stop us

Zero-inflated truncated generalized Pareto distribution for the analysis of radio audience data

Extreme value data with a high clump-at-zero occur in many domains. Moreover, it might happen that the observed data are either truncated below a given threshold and/or might not be reliable enough below that threshold because of the recording devices. These situations occur, in particular, with radio audience data measured using personal meters that record environmental noise every minute, that is then matched to one of the several radio programs. There are therefore genuine zeros for respondents not listening to the radio, but also zeros corresponding to real listeners for whom the match between the recorded noise and the radio program could not be achieved. Since radio audiences are important for radio broadcasters in order, for example, to determine advertisement price policies, possibly according to the type of audience at different time points, it is essential to be able to explain not only the probability of listening to a radio but also the average time spent listening to the radio by means of the characteristics of the listeners. In this paper we propose a generalized linear model for zero-inflated truncated Pareto distribution (ZITPo) that we use to fit audience radio data. Because it is based on the generalized Pareto distribution, the ZITPo model has nice properties such as model invariance to the choice of the threshold and from which a natural residual measure can be derived to assess the model fit to the data. From a general formulation of the most popular models for zero-inflated data, we derive our model by considering successively the truncated case, the generalized Pareto distribution and then the inclusion of covariates to explain the nonzero proportion of listeners and their average listening time. By means of simulations, we study the performance of the maximum likelihood estimator (and derived inference) and use the model to fully analyze the audience data of a radio station in a certain area of Switzerland.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS358 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org

Steric Constraints as a Global Regulation of Growing Leaf Shape

Shape is one of the important characteristics for the structures observed in living organisms. Whereas biologists have proposed models where the shape is controlled on a molecular level [1], physicists, following Turing [2] and d'Arcy Thomson [3], have developed theories where patterns arise spontaneously [4]. Here, we propose a volume constraint that restricts the possible shapes of leaves. Focusing on palmate leaves, the central observation is that developing leaves first grow folded inside a bud, limited by the previous and subsequent leaves. We show that growing folded in this small volume controls globally the leaf development. This induces a direct relationship between the way it was folded and the final unfolded shape of the leaf. These dependencies can be approximated as simple geometrical relationships that we confirm on both folded embryonic and unfolded mature leaves. We find that independently of their position in the phylogenetic tree, these relationships work for folded species, but do not work for non-folded species. This steric constraint is a simple way to impose a global regulation for the leaf growth. Such steric regulation should be more general and considered as a new simple means of global regulation.Comment: 6 pages 4 figures, Supplementary materials (8 pages, 7 figures

Unmanned Aerial Systems for Wildland and Forest Fires

Wildfires represent an important natural risk causing economic losses, human death and important environmental damage. In recent years, we witness an increase in fire intensity and frequency. Research has been conducted towards the development of dedicated solutions for wildland and forest fire assistance and fighting. Systems were proposed for the remote detection and tracking of fires. These systems have shown improvements in the area of efficient data collection and fire characterization within small scale environments. However, wildfires cover large areas making some of the proposed ground-based systems unsuitable for optimal coverage. To tackle this limitation, Unmanned Aerial Systems (UAS) were proposed. UAS have proven to be useful due to their maneuverability, allowing for the implementation of remote sensing, allocation strategies and task planning. They can provide a low-cost alternative for the prevention, detection and real-time support of firefighting. In this paper we review previous work related to the use of UAS in wildfires. Onboard sensor instruments, fire perception algorithms and coordination strategies are considered. In addition, we present some of the recent frameworks proposing the use of both aerial vehicles and Unmanned Ground Vehicles (UV) for a more efficient wildland firefighting strategy at a larger scale.Comment: A recent published version of this paper is available at: https://doi.org/10.3390/drones501001

Substrate elucidation and mutasynthesis: Characterisation of the biosynthetic pathway of a tripyrrolic secondary metabolite, prodigiosin

A wide variety of biological activity can be found in the realm of secondary metabolites. The tripyrrole prodigiosin illustrates this perfectly with activities ranging from antimicrobial to immunosuppressive and anticancer. Microorganisms producing the red pigment prodigiosin were first isolated more than 150 years ago. Yet, its structure was only elucidated in the 1960s and the biosynthetic pathway remained mainly unknown until the 2000s. This secondary metabolite results from a bifurcated pathway where monopyrrole 2-methyl-3-pentyl-1H-pyrrole (MAP) and bipyrrole 4-methoxy-1H,1'H-2,2'-bipyrrole (MBC) are produced independently before condensation. As MBC is an intermediate in the synthesis of other natural products, the enzymes involved in its formation have been well characterised. In contrast, the three enzymes – PigD, PigE and PigB – involved in the formation of MAP are specific to the biosynthesis of prodigiosin and less is known about them. This thesis focuses on the latter two enzymes. PigE was first described as a transaminase catalysing the transformation of 3-acetyloctanal into 3-acetyloctylamine (which cyclises to form dihydroMAP) and this activity has been confirmed by feeding intermediates to various gene-knockout strains. However, in vitro studies have demonstrated that 3-acetyloctanal could not be the product of PigD. In addition, bioinformatics analysis of its amino acid sequence showed that PigE has two domains: a transaminase Cterminal moiety and an unspecified N-terminal one, which we propose is a thioester reductase that converts a 3-acetyloctanoyl thioester to 3-acetyloctanal. Attempted chemical complementation of a pigD-knockout strain of Serratia using synthetic thioester, carboxylic acid and aldehyde substrates showed that both the thioester and the aldehyde can be used for pigment production, indicating that a thioester reductase is involved in prodigiosin biosynthetic pathway. Furthermore, the PigE protein was expressed in a heterogeneous host, purified and submitted to a number of activity and kinetic assays, which demonstrated that it can reduce a 3-acetyloctanoyl thioester substrate. The oxidation of dihydroMAP to MAP had previously been shown to be catalysed by an FADdependent oxidase PigB. The kinetics of HapB, a homologue of PigB had been studied by a previous group member. To take this project further we studied the substrate flexibility of the enzyme and used it to form new analogues of prodigiosin by mutasynthesis. Ten analogues of dihydroMAP with modifications either in the C2 or C3 positions were synthesised. Both extensions and truncations in the length of the chain at the C3 position could be accepted, whereas alkyl chains longer than 3 carbons on the C2 position could not be accommodated. Similar results were found in vivo when the analogues were fed to a pigD-knockout strain of Serratia, showing that PigB and the condensing enzyme PigC shared similar flexibility. Eight analogues of prodigiosin were hence obtained and their antimicrobial activities against Gram-positive and Gram-negative bacteria were assessed.BBSRC Frances and Augustus Newman Fundatio

Problem-Solving Knowledge Mining from Users’\ud Actions in an Intelligent Tutoring System

In an intelligent tutoring system (ITS), the domain expert should provide\ud relevant domain knowledge to the tutor so that it will be able to guide the\ud learner during problem solving. However, in several domains, this knowledge is\ud not predetermined and should be captured or learned from expert users as well as\ud intermediate and novice users. Our hypothesis is that, knowledge discovery (KD)\ud techniques can help to build this domain intelligence in ITS. This paper proposes\ud a framework to capture problem-solving knowledge using a promising approach\ud of data and knowledge discovery based on a combination of sequential pattern\ud mining and association rules discovery techniques. The framework has been implemented\ud and is used to discover new meta knowledge and rules in a given domain\ud which then extend domain knowledge and serve as problem space allowing\ud the intelligent tutoring system to guide learners in problem-solving situations.\ud Preliminary experiments have been conducted using the framework as an alternative\ud to a path-planning problem solver in CanadarmTutor