•We present a novel taxonomy of mobility types of scientists based on bibliometric data.•Four mobility classes are presented: not mobile researchers, directional travelers, non-directional travelers ...and migrants.•Travelers are defined as those who have affiliation ties with more than one country, always maintaining a link with their country of origin.•We present a brief analysis worldwide to illustrate the potential of these mobility classes to inform science policy.•This taxonomy can be applied to several levels of analysis, demonstrating scientific mobility within nations, institutions, sectors or disciplines, as well as internationally.
This paper presents a methodological framework for developing scientific mobility indicators based on bibliometric data. We identify nearly 16 million individual authors from publications covered in the Web of Science for the 2008–2015 period. Based on the information provided across individuals’ publication records, we propose a general classification for analyzing scientific mobility using institutional affiliation changes. We distinguish between migrants--authors who have ruptures with their country of origin--and travelers--authors who gain additional affiliations while maintaining affiliation with their country of origin. We find that 3.7% of researchers who have published at least one paper over the period are mobile. Travelers represent 72.7% of all mobile scholars, but migrants have higher scientific impact. We apply this classification at the country level, expanding the classification to incorporate the directionality of scientists’ mobility (i.e., incoming and outgoing). We provide a brief analysis to highlight the utility of the proposed taxonomy to study scholarly mobility and discuss the implications for science policy.
The brains of humans and other mammals are highly vulnerable to interruptions in blood flow and decreases in oxygen levels. Here we describe the restoration and maintenance of microcirculation and ...molecular and cellular functions of the intact pig brain under ex vivo normothermic conditions up to four hours post-mortem. We have developed an extracorporeal pulsatile-perfusion system and a haemoglobin-based, acellular, non-coagulative, echogenic, and cytoprotective perfusate that promotes recovery from anoxia, reduces reperfusion injury, prevents oedema, and metabolically supports the energy requirements of the brain. With this system, we observed preservation of cytoarchitecture; attenuation of cell death; and restoration of vascular dilatory and glial inflammatory responses, spontaneous synaptic activity, and active cerebral metabolism in the absence of global electrocorticographic activity. These findings demonstrate that under appropriate conditions the isolated, intact large mammalian brain possesses an underappreciated capacity for restoration of microcirculation and molecular and cellular activity after a prolonged post-mortem interval.
The foundation of organizations and knowledge-based economies is widely considered to be human capital and knowledge workers. This review synthesizes prior research on skilled migration, brain gain, ...and brain drain, occurring because of the cross-border migration of skilled professionals. The review comprises 75 studies, synthesizes findings, and develops a conceptual framework for enablers of skilled migration across the border, resulting in brain drain and brain gain. We support previous theories on international migration, stating wage differentials, employment, better earning, and family life as reasons for migration, as well as we provide the basis of Maslow's hierarchy of needs theory and Herzberg's two-factor theory to explain the phenomenon of skilled migration. The conceptual model proposed elucidates the brain drain and brain gain outcomes, thereby surfacing a formative base for future research agenda.
One concern about the use of normothermic regional perfusion (NRP) in controlled donation after the circulatory determination of death (cDCD) is that the brain may be perfused. We aimed to ...demonstrate that certain technical maneuvers preclude such brain perfusion. A nonrandomized trial was performed on cDCD donors. In abdominal normothermic regional perfusion (A-NRP), the thoracic aorta was blocked with an intra-aortic occlusion balloon. In thoracoabdominal normothermic regional perfusion (TA-NRP), the arch vessels were clamped and the cephalad ends vented to the atmosphere. The mean intracranial arterial blood pressure (ICBP) was invasively measured at the circle of Willis. Ten cDCD donors subject to A-NRP or TA-NRP were included. Mean ICBP and mean blood pressure at the thoracic and the abdominal aorta during the circulatory arrest were 17 (standard deviation SD, 3), 17 (SD, 3), and 18 (SD, 4) mmHg, respectively. When A-NRP started, pressure at the abdominal aorta increased to 50 (SD, 13) mmHg, while the ICBP remained unchanged. When TA-NRP was initiated, thoracic aorta pressure increased to 71 (SD, 18) mmHg, but the ICBP remained unmodified. Recorded values of ICBP during NRP were 10 mmHg. In conclusion, appropriate technical measures applied during NRP preclude perfusion of the brain in cDCD. This study might help to expand NRP and increase the number of organs available for transplantation.
Background and purpose
In contrast to anterior circulation stroke (ACS), there is no evidence from randomized trials that mechanical thrombectomy (MT) with modern stent retrievers or ...thromboaspiration is safe and effective in posterior circulation stroke (PCS).
Methods
The present analysis was based on the prospective multicentre Registry on Revascularization in Ischemic Stroke Patients (REVASK) in Germany. Demographic data, periprocedural times and complications, recanalization rates, and functional outcome at discharge and after 3 months were compared between 139 consecutive patients with PCS (84.9% basilar artery, 16.5% vertebral artery and 4.3% posterior cerebral artery occlusion) and 961 patients with ACS treated with MT.
Results
Compared to ACS, PCS patients were significantly younger (65 vs. 69 years, P = 0.021) and had a lower median National Institutes of Health Stroke Scale (NIHSS) score at baseline (12 vs. 15, P = 0.024). Patients with PCS had a significantly longer time delay between symptom onset and both start and end of the MT procedure. Successful recanalization and thrombectomy passes did not significantly differ between the two groups. No symptomatic intracranial haemorrhage occurred in PCS compared to 3% in ACS (P = 0.010). The median NIHSS score at discharge was 3 in PCS and 4 in ACS. Favourable functional outcome at 3 months (modified Rankin Scale 0–2 38.0% vs. 42.6%, P = 0.392) and mortality (33.7% vs. 30.8%, P = 0.539) did not differ significantly between PCS and ACS.
Conclusions
The study suggests that MT in PCS shows a lower risk of symptomatic intracranial haemorrhage and similar effectiveness compared to ACS. PCS patients also seem to benefit from MT started beyond 6 h after symptom onset.
The devastating russian military invasion of Ukraine forced millions of people to flee their homes. Among those affected are highly skilled scientists, resulting in a significant loss of human ...capital for Ukraine, which is crucial for the post-war reconstruction. To address this pressing issue, the Young Scientists Council (YSC) at the Ministry of Education and Science of Ukraine launched the “Ukrainian Science Diaspora” initiative to mitigate the brain drain.The purpose of this study is to outline the first steps taken by this initiative. Moreover, it demonstrates lessons learned from the pilot meetings. The essence of the initiative is to keep links with scholars who left Ukraine and join the efforts of different migration waves of Ukrainian scientists for the further rebuilding of Ukraine. The YSC and other institutions prepared the analytical report on the needs and plans of Ukrainian scientists abroad. In addition, the paper highlights various events and activities organized by the YSC and other self-formed associations of Ukrainian scientists worldwide, working together to establish networks that could take the form of public organizations or be part of local unions of scientists. At present, efforts are focused on identifying Ukrainian scientists interested in joining this initiative, with the ultimate goal of identifying areas where Ukrainian scientists can participate in post-war reconstruction. The success of this initiative will undoubtedly play a crucial role in ensuring that Ukraine can retain its valuable human capital and continue to thrive in the face of adversity.
AcknowledgmentThis study is co-funded by the European Union through the European Education and Culture Executive Agency (EACEA) within the project “Europeanisation of Doctoral Studies in Line with the Innovative Doctoral Training Principles in Europe: Towards a Common Future” 101083493 – EDOCS – ERASMUS-JMO-2022-HEI-TCH-RSCH https://edocs.snau.edu.ua/en/
•We reconstruct and examine the global inter-city mobility of millions of scientist.•Scientists in global cities attract more citations than their peers elsewhere.•Prolific scientists gravitate ...toward global cities and remain there.•Scientific mobility contributes to the superior performance of global cities.
Global cities boast higher rates of innovation as measured through patent and scientific production. However, the source of the location advantage of innovation hubs is still debated in the literature, with arguments ranging from localized knowledge spillovers to network effects. Thanks to an extensive data set of individual scientist career paths, we shed new light on the role of scientist location choices in determining the superior innovative performance of global cities. We analyze the career paths of around two million researchers over a decade across more than two thousand cities around the globe. First, we show that scientists active in global cities are more productive in terms of citation weighted publications. We then show that this superior performance is in part driven by highly prolific scientists moving and remaining preferentially in global cities, i.e., central cities in the international scientist mobility network. The overall picture that emerges is that global cities are better positioned to attract and retain prolific scientists than more peripheral cities.
In recent years, several works have addressed the problem of modeling blood flow phenomena in veins, as a response to increasing interest in modeling pathological conditions occurring in the venous ...network and their connection with the rest of the circulatory system. In this context, one-dimensional models have proven to be extremely efficient in delivering predictions in agreement with
observations. Pursuing the increase of anatomical accuracy and its connection to physiological principles in haemodynamics simulations, the main aim of this work is to describe a novel closed-loop Anatomically-Detailed Arterial-Venous Network (ADAVN) model. An extremely refined description of the arterial network consisting of 2,185 arterial vessels is coupled to a novel venous network featuring high level of anatomical detail in cerebral and coronary vascular territories. The entire venous network comprises 189 venous vessels, 79 of which drain the brain and 14 are coronary veins. Fundamental physiological mechanisms accounting for the interaction of brain blood flow with the cerebro-spinal fluid and of the coronary circulation with the cardiac mechanics are considered. Several issues related to the coupling of arterial and venous vessels at the microcirculation level are discussed in detail. Numerical simulations are compared to patient records published in the literature to show the descriptive capabilities of the model. Furthermore, a local sensitivity analysis is performed, evidencing the high impact of the venous circulation on main cardiovascular variables.
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