Maximum velocity of a fluxon in a stack of coupled Josephson junctions

Dynamics of a fluxon in a stack of inductively coupled long Josephson junctions is studied analytically and numerically. We demonstrate that the fluxon has a maximum velocity, which does not necessarily coincide with any of the characteristic Josephson plasma wave velocities. The maximum fluxon velocity is found by means of numerical simulations of the quasi-infinite system. Using the variational approximation, we propose a simple analytical formula for the dependence of the fluxon's maximum velocity on the coupling constant and on the distribution of critical currents in different layers. This analysis yields rather precise results in the limit of small dissipation. The simulations also show that nonzero dissipation additionally stabilizes the fluxon.Comment: 8 pages, 5 figures, 1 table. submitted to Phys. Lett. A. Suggestions and criticism are welcom

Neuro-hormonal effects of physical activity in the elderly.

Thanks to diagnostic and therapeutic advances, the elderly population is continuously increasing in the western countries. Accordingly, the prevalence of most chronic age-related diseases will increase considerably in the next decades, thus it will be necessary to implement effective preventive measures to face this epidemiological challenge. Among those, physical activity exerts a crucial role, since it has been proven to reduce the risk of cardiovascular diseases, diabetes, obesity, cognitive impairment and cancer. The favorable effects of exercise on cardiovascular homeostasis can be at least in part ascribed to the modulation of the neuro-hormonal systems implicated in cardiovascular pathophysiology. In the elderly, exercise has been shown to affect catecholamine secretion and biosynthesis, to positively modulate the renin-angiotensin-aldosterone system and to reduce the levels of plasma brain natriuretic peptides. Moreover, drugs modulating the neuro-hormonal systems may favorably affect physical capacity in the elderly. Thus, efforts should be made to actually make physical activity become part of the therapeutic tools in the elderly. © 2013 Femminella, de Lucia, Iacotucci, Formisano, Petraglia, Allocca, Ratto, DAmico, Rengo, Pagano, Bonaduce, Rengo and Ferrara

Histological analysis of thrombi retrieved after acute ischemic stroke from large vessel occlusion: from research to clinical practice

Emergent reperfusion therapies have improved acute ischemic stroke prognosis, but many patients are still bound to bad clinical outcome, probably because of our incomplete knowledge of its pathophysiology. Thanks to mechanical thrombectomy, occluding material is available for histological analysis. Several studies investigated the possible relationship between thrombus composition and clinical, procedural, and radiological variables of acute ischemic stroke. The potential value of thrombus analysis as a tool for clinical practice and research is still not defined, as data from the literature are heterogeneous and sometimes conflicting. We propose a review of the existing literature regarding histological analysis of thrombi in acute ischemic stroke. We classified articles on clot composition according to the clinical variable explored in each study. We first distinguished articles about etiology, procedural, and radiological variables, and then we performed a subclassification for each group. This review could help both in the interpretation of thrombus analysis in clinical practice and in its usage for future researc

67,000 years of coastal engagement at Panga ya Saidi, eastern Africa

The antiquity and nature of coastal resource procurement is central to understanding human evolution and adaptations to complex environments. It has become increasingly apparent in global archaeological studies that the timing, characteristics, and trajectories of coastal resource use are highly variable. Within Africa, discussions of these issues have largely been based on the archaeological record from the south and northeast of the continent, with little evidence from eastern coastal areas leaving significant spatial and temporal gaps in our knowledge. Here, we present data from Panga ya Saidi, a limestone cave complex located 15 km from the modern Kenyan coast, which represents the first long-term sequence of coastal engagement from eastern Africa. Rather than attempting to distinguish between coastal resource use and coastal adaptations, we focus on coastal engagement as a means of characterising human relationships with marine environments and resources from this inland location. We use aquatic mollusc data spanning the past 67,000 years to document shifts in the acquisition, transportation, and discard of these materials, to better understand long-term trends in coastal engagement. Our results show pulses of coastal engagement beginning with low-intensity symbolism, and culminating in the consistent low-level transport of marine and freshwater food resources, emphasising a diverse relationship through time. Panga ya Saidi has the oldest stratified evidence of marine engagement in eastern Africa, and is the only site in Africa which documents coastal resources from the Late Pleistocene through the Holocene, highlighting the potential archaeological importance of peri-coastal sites to debates about marine resource relationships.Introduction Site location and description Materials and methods Results - PYS mollusc assemblage characteristics - Comparative trends in mollusc discard Discussion Conclusio

Increased expression of antimüllerian hormone and its receptor in endometriosis

To evaluate antimüllerian hormone (AMH) and AMH receptor II (AMHRII) mRNA and protein expression in endometrium and in ovarian or deep lesions of women with endometriosis

Microhabitat variability in Human Evolution

Climate variability and hominin evolution are inextricably linked. Yet, hypotheses examining the impact of large-scale climate shifts on hominin landscape ecology are often constrained by proxy data coming from off-site lake and ocean cores and temporal offsets between paleoenvironmental and archaeological records. Additionally, landscape response data (most commonly, records of vegetation change), are often used as a climate proxy. This is problematic as it assumes that vegetation change signifies global or regional climate shifts without accounting for the known non-linear behavior of ecological systems and the often-significant spatial heterogeneity in habitat structure and response. The exploitation of diverse, rapidly changing habitats by Homo by at least two million years ago highlights that the ability to adapt to landscapes in flux had emerged by the time of our genus’ African origin. To understand ecosystem response to climate variability, and hominin adaptations to environmental complexity and ecological diversity, we need cross-disciplinary datasets in direct association with stratified archaeological and fossil assemblages at a variety of temporal and spatial scales. In this article, we propose a microhabitat variability framework for understanding Homo’s adaptability to fluctuating climates, environments, and resource bases. We argue that the exploitation of microhabitats, or unique ecologically and geographically defined areas within larger habitats and ecoregions, was a key skill that allowed Homo to adapt to multiple climates zones and ecoregions within and beyond Africa throughout the Pleistocene.Introduction Microhabitat variability - Identifying Microhabitat Variability Environmental and climate variability and human evolution Ecosystem resilience in face of climate change Microhabit at variability and human evolution - Microhabitat Variability at Oldupai Gorge: A Case Study Expanding the microhabitat variability framework Conclusio

Iron Age hunting and herding in coastal eastern Africa: ZooMS identification of domesticates and wild bovids at Panga ya Saidi, Kenya

The morphological differentiation of African bovids in highly fragmented zooarchaeological assemblages is a major hindrance to reconstructing the nature and spread of pastoralism in sub-Saharan Africa. Here we employ collagen peptide mass fingerprinting, known as Zooarchaeology by Mass Spectrometry (ZooMS), coupled with recently published African ZooMS reference datasets, to identify domesticates and wild bovids in Iron Age assemblages at the cave site of Panga ya Saidi in southeast Kenya. Through ZooMS we have identified all three major African livestock—sheep (Ovis aries), goat (Capra hircus) and cattle (Bos taurus)—at the site for the first time. The results provide critical evidence for the use of domesticates by resident foraging populations during the Iron Age, the period associated with the arrival of food production in coastal Kenya. ZooMS results show that livestock at Panga ya Saidi form a minor component of the assemblage compared to wild bovids, demonstrating the persistence of hunting and the secondary role of acquiring livestock in hunter-gatherer foodways during the introduction of agro-pastoralism. This study sheds new light on the establishment of food production in coastal eastern Africa, particularly the role of interactions between hunter-gatherers and neighbouring agro-pastoral groups in what was a protracted regional transition to farming.1. Introduction 2. Background 2.1. Problems with differentiating domesticates in African zooarchaeology 2.2. ZooMS in Africa 2.3. Panga ya Saidi, southeastern Kenya 2.3.1. Ecological setting 2.3.2. Archaeological background 3. Materials and methods 3.1. Sample Selection 3.2. ZooMS protocol 4. Results 5. Discussion 5.1. The impact of domestic livestock on hunting economies at PYS 5.2. Livestock trading or herding? 5.3. The role of domesticates in forager-farmer interactions 5.4. Behavioural and ecological implications of klipspringers at PYS 6. Conclusio

Early holocene human burials from Fa Hien-lena and Kuragala, Sri Lanka

<p>Few human burials from Sri Lankan archaeological contexts have been described. Here we report on the analysis of two early Holocene skeletons, FH8, a young adult female skeleton excavated from Fa Hien-lena and dated to 10,640-10,139 cal BP, and BK1, a middle adult male skeleton excavated at Kuragala and dated to 7,170-6,950 cal BP.  The skeletons are both highly fragmentary, which poses challenges for their thorough analysis. However, this paper describes the archaeological context, mortuary treatment and archaeothanatology of the burials, post-mortem taphonomy of human remains, the osteobiography of both individuals, and some general observations on their morphology relative to one another and a broader range of late Pleistocene and Holocene foragers. The results demonstrate common elements of funerary treatment between these two burials, such as interment on the left side with right hands placed near or over the face. The FH8 individual died at a young age and shows some signs of early childhood stress. Both skeletons show moderate to high degrees of tooth wear for their relative ages, and no evidence for dental disease. The body size estimates of FH8 and BK1 fall in the range that would be expected of tropical or temperate forest foragers, although BK1 has a relatively low body mass relative to stature, which aligns his phenotype with populations of more arid environments. We demonstrate that much can be potentially learned about human populations and prehistoric behaviours from skeletal analyses. </p>Introduction Fa Hien-lena Kuragala Mortuary Context and Archaeothanatology Fa Hien-lena FH8 Kuragala (BK1) Common elements of each burial Skeletal and Dental Inventories and Taphonomy Osteobiographic analyses Morphology and other observations Discussio

The shape of a moving fluxon in stacked Josephson junctions

We study numerically and analytically the shape of a single fluxon moving in a double stacked Josephson junctions (SJJ's) for various junction parameters. We show that the fluxon in a double SJJ's consists of two components, which are characterized by different Swihart velocities and Josephson penetration depths. The weight coefficients of the two components depend on the parameters of the junctions and the velocity of the fluxon. It is shown that the fluxon in SJJ's may have an unusual shape with an inverted magnetic field in the second junction when the velocity of the fluxon is approaching the lower Swihart velocity. Finally, we study the influence of fluxon shape on flux-flow current-voltage characteristics and analyze the spectrum of Cherenkov radiation for fluxon velocity above the lower Swihart velocity. Analytic expression for the wavelength of Cherenkov radiation is derived.Comment: 12 pages, 12 figure