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Velocity correlation is an important feature for animal groups performing collective motions. Previous studies have mostly focused on the velocity correlation in a single ecological context. It is unclear whether correlation characteristics vary in a single species in different contexts. Here, we studied the velocity correlations in jackdaw flocks in two different contexts: transit flocks where birds travel from one location to another, and mobbing flocks where birds respond to an external stimulus. We found that in both contexts, although the interaction rules are different, the velocity correlations remain scale-free, i.e. the correlation length (the distance over which the velocity of two individuals is similar) increases linearly with the group size. Furthermore, we found that the correlation length is independent of the group density for transit flocks, but increases with increasing group density in mobbing flocks. This result confirms a previous observation that birds obey topological interactions in transit flocks, but switch to metric interactions in mobbing flocks. Finally, in both contexts, the impact of group polarization on correlation length is not significant. Our results suggest that wild animals are always able to respond coherently to perturbations regardless of context.

Collective behaviour is typically thought to arise from individuals following fixed interaction rules. The possibility that interaction rules may change under different circumstances has thus only rarely been investigated. Here we show that local interactions in flocks of wild jackdaws (Corvus monedula) vary drastically in different contexts, leading to distinct group-level properties. Jackdaws interact with a fixed number of neighbours (topological interactions) when traveling to roosts, but coordinate with neighbours based on spatial distance (metric interactions) during collective anti-predator mobbing events. Consequently, mobbing flocks exhibit a dramatic transition from disordered aggregations to ordered motion as group density increases, unlike transit flocks where order is independent of density. The relationship between group density and group order during this transition agrees well with a generic self-propelled particle model. Our results demonstrate plasticity in local interaction rules and have implications for both natural and artificial collective systems., Modelling collective behaviour in different circumstances remains a challenge because of uncertainty related to interaction rule changes. Here, the authors report plasticity in local interaction rules in flocks of wild jackdaws with implications for both natural and artificial collective systems.

Prison in-reach mental health services are reasonably well developed in advanced economies, but virtually nonexistent in low- and middle-income countries. We describe the development of a small prison in-reach project in Somaliland, a self-declared independent state which has experienced conflict and poverty in equal measure. After careful planning and cooperation with local agencies, the service provides sessional input to a regional prison, including assessment and treatment of a wide range of psychiatric conditions. The project has had some unexpected benefits, which are described. The success of the project reflects the effectiveness of collaboration between local stakeholders and international agencies, and could be used as a model for the development of in-reach services in other low-income countries.

As one of nature's most striking examples of collective behaviour, bird flocks have attracted extensive research. However, we still lack an understanding of the attractive and repulsive forces that govern interactions between individuals within flocks and how these forces influence neighbours' relative positions and ultimately determine the shape of flocks. We address these issues by analysing the three-dimensional movements of wild jackdaws ( Corvus monedula ) in flocks containing 2–338 individuals. We quantify the social interaction forces in large, airborne flocks and find that these forces are highly anisotropic. The long-range attraction in the direction perpendicular to the movement direction is stronger than that along it, and the short-range repulsion is generated mainly by turning rather than changing speed. We explain this phenomenon by considering wingbeat frequency and the change in kinetic and gravitational potential energy during flight, and find that changing the direction of movement is less energetically costly than adjusting speed for birds. Furthermore, our data show that collision avoidance by turning can alter local neighbour distributions and ultimately change the group shape. Our results illustrate the macroscopic consequences of anisotropic interaction forces in bird flocks, and help to draw links between group structure, local interactions and the biophysics of animal locomotion.

Supplementary text of imaging system, data collection procedures, and additional analysis; and supplementary figures S1 to S13

Details of event selection criteria, camera calibration, tracking, calculation of force maps and curves; Sample data analysis code; and supplementary figures and table.

Working capital management (WCM) seeks to improve the efficiency of a firm’s operation through managing its inventory, accounts receivable, and accounts payable. Supply chain networks composed of various entities, e.g. supplier, manufacturer, which coordinate in order to deliver the finished product to the customer at the right time. The average days that it takes for a company to convert a dollar invested in raw material into a dollar collected from customer is defined as cash conversion cycle (CCC). A low CCC implies that the company has lower financial cost to fund its business operation. It goes without saying that, all firms are willing to decrease their financial cost through diminishing CCC, however minimization of the CCC for the supply chain echelons are in conflict, as one firm’s payable period is another firm’s receivable period. In this paper, a simulation- based optimization (SBO) model is developed to make trade-offs between conflicting cash conversion cycle minimizations for supply chain members through finding optimal values to the financial and inventory decisions parameters. The results indicated that CCC of the supply chain entities can be decreased significantly by employing optimal values of inventory and financial decisions parameters.

Tracking the movements of birds in three dimensions is integral to a wide range of problems in animal ecology, behaviour and cognition. Multi-camera stereo-imaging has been used to track the three-dimensional (3D) motion of birds in dense flocks, but precise localization of birds remains a challenge due to imaging resolution in the depth direction and optical occlusion. This paper introduces a portable stereo-imaging system with improved accuracy and a simple stereo-matching algorithm that can resolve optical occlusion. This system allows us to decouple body and wing motion, and thus measure not only velocities and accelerations but also wingbeat frequencies along the 3D trajectories of birds. We demonstrate these new methods by analysing six flocking events consisting of 50 to 360 jackdaws (Corvus monedula) and rooks (Corvus frugilegus) as well as 32 jackdaws and 6 rooks flying in isolated pairs or alone. Our method allows us to (i) measure flight speed and wingbeat frequency in different flying modes; (ii) characterize the U-shaped flight performance curve of birds in the wild, showing that wingbeat frequency reaches its minimum at moderate flight speeds; (iii) examine group effects on individual flight performance, showing that birds have a higher wingbeat frequency when flying in a group than when flying alone and when flying in dense regions than when flying in sparse regions; and (iv) provide a potential avenue for automated discrimination of bird species. We argue that the experimental method developed in this paper opens new opportunities for understanding flight kinematics and collective behaviour in natural environments.

This was a cross-over efficacy study design. To determine spasticity differences between static and dynamic standing training in individuals with spinal cord injury (SCI). Vancouver, Canada. Ten individuals with SCI who could stand with or without bracing or supports participated in both dynamic and static standing training (one session each, 2 days apart) using a Segway. The primary outcome was spasticity as measured by Visual Analog Scale (VAS), Modified Ashworth Scale (MAS) and electromyography (EMG) of the quadriceps, hamstrings, adductors and gastrocnemius. There was no statistically detectable difference in spasticity between dynamic and static standing training in individuals with SCI as measured by VAS, MAS or EMG, although there was a trend towards decreased spasticity after the dynamic training. There is no significant difference in spasticity outcomes between static and dynamic standing training on a Segway for individuals with SCI. This research was funded by Natural Sciences and Engineering Research Council of Canada and International Collaboration on Repair Discoveries.

Box plots of wingbeat frequency averaged over flapping modes after excluding rooks (that is, birds with mean wingbeat frequency mean(N3m) + std(N3m).

Wingbeat frequencies for 12 jackdaws and 8 rooks flying in mixed-species flocks. The birds’ species was manually identified on the basis of visible morphological characteristics. Each value is obtained by averaging over the flapping modes. The last column shows the mean values and standard errors of wingbeat frequencies for each species.

Prison in-reach mental health services are reasonably well developed in advanced economies, but virtually nonexistent in low-and middle-income countries. We describe the development of a small prison in-reach project in Somaliland, a self-declared independent state which has experienced conflict and poverty in equal measure. After careful planning and cooperation with local agencies, the service provides sessional input to a regional prison, including assessment and treatment of a wide range of psychiatric conditions. The project has had some unexpected benefits, which are described. The success of the project reflects the effectiveness of collaboration between local stakeholders and international agencies, and could be used as a model for the development of in-reach services in other low-income countries.

The rapid, cohesive turns of bird flocks are one of the most vivid examples of collective behaviour in nature, and have attracted much research. Three-dimensional imaging techniques now allow us to characterize the kinematics of turning and their group-level consequences in precise detail. We measured the kinematics of flocks of wild jackdaws executing collective turns in two contexts: during transit to roosts and anti-predator mobbing. All flocks reduced their speed during turns, probably because of constraints on individual flight capability. Turn rates increased with the angle of the turn so that the time to complete turns remained constant. We also find that context may alter where turns are initiated in the flocks: for transit flocks in the absence of predators, initiators were located throughout the flocks, but for mobbing flocks with a fixed ground-based predator, they were always located at the front. Moreover, in some transit flocks, initiators were far apart from each other, potentially because of the existence of subgroups and variation in individual interaction ranges. Finally, we find that as the group size increased the information transfer speed initially increased, but rapidly saturated to a constant value. Our results highlight previously unrecognized complexity in turning kinematics and information transfer in social animals.

Hurler disease or mucopolysaccharidosis type I (MPS-I) is an autosomal-recessive lysosomal storage disease caused by a defect in α-L-iduronidase (IDUA).1,2 It is the most common of the mucopolysaccharidoses, with an incidence of 1 per 75 000 live births.3 Deficiency of the IDUA enzyme leads to a pathological accumulation of glycosaminoglycans (GAG) in the brain and other organs. Typical central nervous system (CNS) features are severe mental retardation, leptomeningeal fibrosis with obstructive hydrocephalus, arachnoid cysts, and sensorineural deafness. Although systemic features of MPS-I can be treated with enzyme replacement therapy or hematopoietic stem cell transplantation, there is currently no accepted treatment for the CNS features. A caveat is that intervention in the neonatal period with bone marrow or cord blood transplantation has shown limited improvement in cognitive performance, likely through cross-correction by stem cells that migrate to the perivascular space.4,5 However, even in the best-case scenario, the existing treatment options do not reverse abnormal cognitive development, are associated with numerous long-term complications, and are prohibitively expensive for many patients. The pathological hallmark of MPS-I in the brain is the accumulation of GAG inside neurons, where they are increased up to 5-fold, as well as in mesodermally derived tissues of the perivascular space, leptomeninges, and choroid plexus, where they are often increased 10-fold and form so-called clear-cell periadventitial inclusions.6 As a result of pathological accumulation of GAG, there is a secondary perturbation of β-galactosidase (originally thought to be the main defect in Hurler disease),7 and consequently, the neuronal inclusions in Hurler disease are made up primarily of gangliosides (GM2, GM3) which are not usually present in substantial amounts in normal brain.8,9 Another downstream enzyme, β-hexosaminidase (defective in Tay-Sachs disease), which breaks down GM2, is upregulated in MPS-I, and normalization of this enzyme was used as a secondary outcome measure in canine gene therapy studies for Hurler disease.10 Our inability to achieve high-level neuronal gene expression throughout the large volume of the human brain is currently an impediment to more effective gene therapy for many neurodegenerative diseases. The purpose of this study was to test the feasibility of minimally invasive viral vector-based CNS gene therapy in Hurler disease and, more specifically, to compare endovascular with intracerebral ventricular (ICV) delivery. Recombinant adeno-associated viral vector (rAAV) was chosen because it is nonpathogenic and is able to express genes in the CNS at very high levels.11 It exists in more than 10 serotypes, most of which specifically transduce neurons when injected intraparenchymally, but some are capable of transducing astrocytes, microglia, ependyma, and other cells to various degrees. To maximize the unit dose per animal, we used a transgenic mouse model12 rather than one of the larger animal models,13,14 with an aggressive endovascular dosing regimen of 1 trillion genomic particles (g.p.) per mouse. We chose rAAV5 vector, which has an advantage of high-level neuronal expression and cellular internalization by the platelet-derived growth factor receptor,15 which also targets ependymal, choroid plexus, and perivascular cells affected in Hurler disease. Another theoretical benefit of rAAV5 is that neutralizing antibody titers are the lowest among AAV serotypes.16 Endovascular gene therapy offers widespread access to the brain but generally requires blood-brain barrier disruption, and until recently, results in animal models were disappointing. Rapoport and colleagues17,18 were the first to show reversible osmotic opening of the blood-brain barrier, and their technique of hyperosmolar disruption remains in widespread use. This method was adapted for clinical use in intra-arterial (IA) chemotherapy for brain tumors19 but has never been used clinically for gene therapy. Endovascular techniques have been used in rats20–22 or mice23 to deliver viral vectors to the brain, but gene expression was significantly less than with intraparenchymal delivery, and the microsurgical techniques are demanding. As a result, this approach was abandoned by the majority of gene therapists, even as microcatheter techniques and vector technology advanced. ICV gene therapy is appealing because the ependymal and meningeal surface area is large and may be particularly suited to Hurler disease, which involves these structures. The original clinical application of ICV gene therapy in 1996 used a nonviral vector with Ommaya reservoirs in patients with Canavan disease together with intravenous mannitol.24 The benefit of mannitol for this route of delivery is the greater bulk flow through the interstitial space and increased permeability of the ependyma, rather than effects on the blood-brain barrier. Systemic mannitol was shown in animal models to increase spread of vectors with ICV or intraparenchymal delivery.24–26 However, as a result of perceived limitations of the ICV route with viral vectors, an intraparenchymal approach with multiple rAAV2 injections and systemic mannitol was subsequently adopted for human use.27,28 At this time, the ICV approach deserves a closer look with new vector technology and techniques to optimize transependymal flow. Our study used rAAV5 vectors in adult animals to deliver foreign genes to the brain via IA or ICV delivery, with mannitol treatment used in both cases. In the first case, mannitol is administered directly to arterial vessels to transiently disrupt the endothelial tight junctions and to allow penetration of vector, whereas in the latter case, mannitol is used to improve bulk flow of rAAV5 through ependyma and interstitial space. We initially tested dose-response and biodistribution using rAAV5–green fluorescent protein (GFP) and then assessed the tolerability and efficacy of a very high unit dose (5 × 1013 viral particles per kg) of the therapeutic vector rAAV5-IDUA. With IA delivery, blood-brain barrier disruption was performed with 25% or 29.1% mannitol, and with ICV delivery, we used 25% mannitol injected systemically or directly into the cerebral ventricle. Our goal with ICV delivery was not merely to assess the use of mannitol, because this is already known to increase vector spread,24,29 but rather to compare the endovascular and ICV delivery routes using the best available techniques. Using either delivery paradigm, we significantly reversed brain pathology in animals with a Hurler phenotype.

Seven mildly mentally handicapped children aged between 6 and 11 years were taught to identify a 10p piece using an errorless learning procedure. These children each underwent 10 trials in which they were presented with two items. One item was a 10p piece, the other item varied depending on the current stage of the programme. The children had to identify the 10p piece and they were reinforced if they made the correct identification. A post-test was then carried out — each child had to identify the three 10p pieces which were in a selection of nine coins placed in the child's hand. Six of the seven children learned the discrimination and the results (t = 7.10, df = 6, p < 0.001) show a significant difference between the error scores on the post-test and pre-test. Very few errors were made during training. These results support the validity and utility of the errorless learning procedure.

Summary Background Patients with chronic obstructive pulmonary disease (COPD) have few options for treatment. The efficacy and safety of the phosphodiesterase-4 inhibitor roflumilast have been investigated in studies of patients with moderate-to-severe COPD, but not in those concomitantly treated with longacting inhaled bronchodilators. The effect of roflumilast on lung function in patients with COPD that is moderate to severe who are already being treated with salmeterol or tiotropium was investigated. Methods In two double-blind, multicentre studies done in an outpatient setting, after a 4-week run-in, patients older than 40 years with moderate-to-severe COPD were randomly assigned to oral roflumilast 500 μg or placebo once a day for 24 weeks, in addition to salmeterol (M2-127 study) or tiotropium (M2-128 study). The primary endpoint was change in prebronchodilator forced expiratory volume in 1 s (FEV 1 ). Analysis was by intention to treat. The studies are registered with ClinicalTrials.gov, number NCT00313209 for M2-127, and NCT00424268 for M2-128. Findings In the salmeterol plus roflumilast trial, 466 patients were assigned to and treated with roflumilast and 467 with placebo; in the tiotropium plus roflumilast trial, 371 patients were assigned to and treated with roflumilast and 372 with placebo. Compared with placebo, roflumilast consistently improved mean prebronchodilator FEV 1 by 49 mL (p 1 was noted in both groups. Furthermore, roflumilast had beneficial effects on other lung function measurements and on selected patient-reported outcomes in both groups. Nausea, diarrhoea, weight loss, and, to a lesser extent, headache were more frequent in patients in the roflumilast groups. These adverse events were associated with increased patient withdrawal. Interpretation Roflumilast improves lung function in patients with COPD treated with salmeterol or tiotropium, and could become an important treatment for these patients. Funding Nycomed.

SUMMARY This article examines the relationship between organizational health and buyer-supplier relationships. Contemporary research has emphasized the need for organizations to move toward closer cooperation. The decision to engage in partnership arrangements is one that has major implications for buyers and suppliers. Using evidence from an exploratory case study, the challenges presented in developing a close, cooperative, and mutually beneficial trading relationship between a buyer and a supplier, where one partner, the buyer, is in a powerful position, are investigated. It is argued that powerful buyers can seriously damage organizational health. The findings provide evidence that it is essential to promote communication structures that encourage dialogue, consultation, and employee participation in decisionmaking. This is particularly important where decisionmaking could benefit from the in-depth technical knowledge of middle and junior managers and shopfloor workers.

This essay both seeks to locate corruption within the current development agenda and to provide a representative overview of the literature, both academic and practitioner, that addresses corruption in this context. The essay provides a background to the study of corruption, and discusses its impact and control in the developmental environment, before following with an annotated selection of representative texts, arranged in the following sections: overview; countries; developmental context and control.