Three-dimensional modelling, disparity and ecology of the first Cambrian apex predators

Radiodonts evolved to become the largest nektonic predators in the Cambrian period, persisting into the Ordovician and perhaps up until the Devonian period. They used a pair of large frontal appendages together with a radial mouth apparatus to capture and manipulate their prey, and had evolved a range of species with distinct appendage morphologies by the Early Cambrian (approx. 521 Ma). However, since their discovery, there has been a lack of understanding about their basic functional anatomy, and thus their ecology. To explore radiodont modes of feeding, we have digitally modelled different appendage morphologies represented by Anomalocaris canadensis , Hurdia victoria , Peytoia nathorsti, Amplectobelua stephenensis and Cambroraster falcatus from the Burgess Shale. Our results corroborate ideas that there was probably a significant (functional and hence behavioural) diversity among different radiodont species with adaptations for feeding on differently sized prey (0.07 cm up to 10 cm). We argue here that Cambroraster falcatus appendages were suited for feeding on suspended particles rather than filtering sediment. Given the limited dexterity and lack of accessory feeding appendages as seen in modern arthropods, feeding must have been inefficient and ‘messy’, which may explain their subsequent replacement by crown-group arthropods, cephalopods and jawed vertebrates.

Subglottic Mass as Isolated Manifestation of Relapsing Polychondritis at Presentation

Relapsing polychondritis (RP) is a rare systemic disease that is characterized by recurrent episodic inflammation of the cartilaginous structures of the body, resulting in their progressive destruction and subsequent replacement with fibrotic scar. We present a case of RP that initially manifested with subglottic involvement and we propose an innovative strategy for the treatment for laryngeal RP in phase of active inflammation. A multidisciplinary approach (rheumatologist, otolaryngologist, immunologist, internist, cardiologist, etc) and adequate follow-up are essential. The timeliness of the diagnosis is fundamental to contain the destructive effects on the cartilages involved.

Spontaneous extrusion of the peritoneal catheter through the intact abdominal wall: report of two cases

Introduction: Ventriculoperitoneal shunt (VPS) is a neurosurgical intervention widely used in the control and treatment of hydrocephalus. The migration of the peritoneal catheter through the abdominal wall is an uncommon complication and its pathophysiology is unknown. Patients and Methods: Two cases of the peritoneal catheter extrusion through the abdominal wall are reported in patients with congenital hydrocephalus. Results: Were discovered after removal of the bypass system and systemic antibiotic therapy, followed by replacement of new bypass, with excellent results. Conclusion: In the presence of this complication, surgical treatment is indicated, through complete removal of the system, systemic antibiotic therapy and subsequent replacement of a new system.

Unexpected Twists: A 61-Year-Old Male with Repeated HeartMate II Complications and Subsequent Replacement with HeartMate III

An outflow graft twist of a left ventricular assist device (LVAD) remains a challenging clinical diagnosis and may even be misdiagnosed for other outflow obstructions. We present a case of a patient with two LVAD exchanges due to suspected outflow graft twisting in both clinical scenarios. As new LVADs continue to be designed and upgraded, clinicians must have a high index of suspicion for this rare complication.

Keynes: The second coming?

This article outlines principles of a modernised macroeconomic framework, drawing on John Maynard Keynes. It explores the historical context in which Keynes? economic theory arose, and the history of its application and subsequent replacement by neoclassical economics. The article argues that any updated Keynesian programme must address three new problems: globalization, wealth inequality and climate change. It sketches out the ways in which these might be addressed.

Increase of the technogenic and ecological safety of the natural gas transportation due to displacement of explosive mixtures with nitrogen

Purpose: To ensure technological and environmental safety it is proposed to use the technology of purging pipeline with compressed nitrogen. Design/methodology/approach: The purpose of the calculation is: to get the graph of the concentration distribution (in volume fraction) of nitrogen and natural gas components depending on the distance from the injection point of nitrogen and the duration of the purge process, to determine of parameters of a non-stationary process, and to establish the optimal parameters of the purging process under conditions of the given flow chart. Findings: In the process of displacement of natural gas, the velocity of the front of nitrogen is one of the main quantities that significantly affect the quality of displacement. To assess the actual technological schemes for transporting natural gas, it is necessary to select the velocity of displacement of explosive mixtures. Research limitations/implications: This technology should be implemented in the conditions of a nitrogen pressure higher than 0.25 MPa. Practical implications: Most favourable conditions for the complete displacement of air and subsequent replacement of nitrogen with natural gas were observed for pressures higher from 1.0 to 1.5 MPa. Originality/value: Complex calculations of the volume of air displaced with nitrogen and natural gas in the process of filling the pipeline were conducted in the research. Boundary conditions on the concentration of the mixture of nitrogen and natural gas were identified.

TRANSFORMATION OF STRUCTURAL COMPONENTS OF MASTICATORY MUSCLES OF IMMATURE ANIMALS IN DIFFERENT STAGES OF MERCAZOLILUM-INDUCED HYPOTHYROIDISM

The aim of the study. The aim of this study was to establish the features of the structural organization of the chewing and lateral pterygoid muscles of immature rats during the developmental stages of experimental hypothyroidism. Materials and methods. The material for the study was the chewing and lateral pterygoid muscles of 48 white mongrel immature rats-males. The following research methods were used: mercazole-induced hypothyroidism modelling, injection method for studying the bloodstream, histological examination of blood vessels and tissue elements, electron microscopy, morphometric analysis, biochemical methods, statistical evaluation of the results. Results. A violation of thyroid homeostasis (a decrease in the concentration of thyroid hormones in the blood) has been established. In the bloodstream, edematous changes are observed histologically and submicroscopically. A decrease in the number of hemocapillaries per unit area and the number of hemocapillaries per muscle fiber have been established morphometrically. In muscle fibers, cross striation with vacuolization of endomysia and perimisia is lost. Edematous changes are observed, which are aggravated depending on the duration of experimental hypothyroidism. The glycolytic muscle fibers are more affected, and the changes are aggravated depending on the duration of the experiment. It has also been found out that there is a redistribution in the amount of muscle fibers. There is a tendency to a decrease in oxidative-glycolytic and a significant increase in glycolytic muscle fibers. The morphological changes that have been found out are accompanied by violations of the macroelement balance, in particular, the content of Ca, P, Mg, which determine the functioning of skeletal muscle tissue. Conclusion. Thus, at different periods of hypothyroidism, edematous changes occur both in the vascular wall and in muscle fibers, which are aggravated depending on the duration of hypothyroidism and are caused by a decrease in the basic metabolic rate, slowing of redox processes and tissue hypoxia. At the same time, chromotropic substances are released from bonds with proteins and accumulate in the intermediate substance with the subsequent replacement of collagen fibers by mucus-like masses.

Transition, ‘Never Again’ and ‘Moving On’

Viewing Irish republican policing memory primarily through a transitional justice lens, this chapter critically examines how Irish republicans, as a principal party to the conflict, approach the difficult issue of ‘dealing with the past’ as both collective victims and perpetrators of human rights violations during the conflict. It will interrogate the range of divergent views within modern Irish republicanism on issues such as victimhood, truth recovery, ‘moving on’ and ‘dealing with the past’. In particular, it looks at how the memory of human rights violations framed the wider policing debate and led to a master narrative of ‘never again’ whereby the value of ‘remembering’ past abuses lay in helping to prevent future repetition. This is placed against a more general backdrop of the stop-start ‘dealing with the past’ process in the North of Ireland that has included the establishment, operation and subsequent replacement of the Historical Enquiries Team (HET), the passage of the Civil Service (Special Advisers) Act (Northern Ireland), and proposals like the Haass/O’Sullivan document and the Stormont House Agreement.

From mental hygiene to mental health: ideology, discourses and practices in Franco’s Spain (1939–75)

Based on an analysis of the discourses, the ideological appropriation and the practical influence of mental hygiene in Spanish psychiatry during the early years of the Francoist regime, this article examines its decline and subsequent replacement by the new concept of mental health promoted by the World Health Organization and other international bodies from the mid-twentieth century. The old approach, essentially focused on the prophylaxis of insanity within the framework of a set of interventionist policies of social defence, was thus transformed from the beginning of the 1960s into a much more ambitious and comprehensive project which sought to promote the psychosocial balance and performance of individuals in the context of increasingly socialized health-related discourses and networks of care.