Straining: Young Men Working through Waithood in Freetown, Sierra Leone

Junge Männer in der prekären Lage andauernder Arbeitslosigkeit oder Unterbeschäftigung im Nachkriegs-Sierra-Leone werden in der öffentlichen und politischen Debatte als wirtschaftlich unbeweglich oder als gefährlich und fYr Gewalt empfänglich dargestellt. Im Gegensatz dazu charakterisieren die Autoren dieses Beitrags die Arbeits- und Lebensbedingungen junger Männer in Freetown als straining – angespannt. Sie untersuchen die Logik dieser Situation permanenter Anspannung, welche innovativen Ideen die jungen Männer entwickeln, welchen Anforderungen sie ausgesetzt sind und wie ihre Aktivitäten sich innerhalb der Stadt verteilen, insbesondere wenn sie mit Verbot und Kriminalisierung des informellen Handels konfrontiert sind. Die Autoren zeigen auf, dass die Anspannung immer wieder neu entsteht und fortdauert, weil (nicht obwohl) junge Männer marginalisiert sind und nur Yber eingeschränkte Handlungsautonomie verfYgen. In dieser Lage entwickeln sie provisorische Aktivitäten, um die Zeit des Wartens, in der sie sich befinden, auf dynamische Weise zu nutzen. In ihrem BemYhen, den eigenen Lebensunterhalt zu sichern und ihre Familien zu unterstYtzen, bewältigen sie gleichzeitig den Übergang von Jugendlichen zu Erwachsenen. Die Autoren plädieren fYr ein differenzierteres Verständnis fYr die arbeitenden jungen Männer in Freetown, aber auch allgemein fYr die große Zahl junger Menschen in afrikanischen Städten

Exploring Ski Tourist Motivations for Active Sport Travel

Ski tourists are one of the largest activity-based market segments in both Canada and the United States (Canadian Tourism Commission, 2003). This study has used an exploratory approach to better understand why ski resort tourists travel for a ski holiday. Members of a Windsor, Ontario ski club participated in focus groups and an action research component that were analyzed to create a Ski Tourist Motivational Model. The factors that were found which impacted the ski tourist\u27s motivation were: risk, facility/destination, price/economic value, social, safety, skill mastery, relaxation, green initiatives and culture. The factors strengths on ski tourist motivation are shown in the model (high, medium or low). The findings are specific to a small group of Windsor skiers and cannot be generalized about the whole skiing population. This study does, however, provide a theoretical basis for future studies to examine a larger ski tourist population

Enhancing and enabling advanced process controls - reducing variability at the source

As for many other disciplines, cell-culture based production is under constant pressure to reduce cost of manufacturing and to increase productivity while maintaining the right product quality. To improve process robustness, consistency and efficiency, Biogen has successfully implemented several Process Analytical Technology (PAT) and Advanced Process Controls (APC) initiatives in large-scale manufacturing. Examples include capacitance-based control of culture transfers and nutrient feeding, control of glucose feeding based on in-line Raman spectroscopy, and the use of process models for real-time process monitoring and prediction of process quality attributes. In general, the performance of any control and monitoring scheme is limited by the noise and uncertainties present in the process and here we present cross-functional efforts to minimize and reduce such variations. Examples include disturbances stemming from auxiliary control loops as well as interference of physical nature, such as capacitance probes being impacted by gas sparge. The resulting performance enhancement in existing PAT/APC efforts as well as the potential to enable novel monitoring and control schemes will be discussed

Robot Fine-Tuning Made Easy: Pre-Training Rewards and Policies for Autonomous Real-World Reinforcement Learning

The pre-train and fine-tune paradigm in machine learning has had dramatic success in a wide range of domains because the use of existing data or pre-trained models on the internet enables quick and easy learning of new tasks. We aim to enable this paradigm in robotic reinforcement learning, allowing a robot to learn a new task with little human effort by leveraging data and models from the Internet. However, reinforcement learning often requires significant human effort in the form of manual reward specification or environment resets, even if the policy is pre-trained. We introduce RoboFuME, a reset-free fine-tuning system that pre-trains a multi-task manipulation policy from diverse datasets of prior experiences and self-improves online to learn a target task with minimal human intervention. Our insights are to utilize calibrated offline reinforcement learning techniques to ensure efficient online fine-tuning of a pre-trained policy in the presence of distribution shifts and leverage pre-trained vision language models (VLMs) to build a robust reward classifier for autonomously providing reward signals during the online fine-tuning process. In a diverse set of five real robot manipulation tasks, we show that our method can incorporate data from an existing robot dataset collected at a different institution and improve on a target task within as little as 3 hours of autonomous real-world experience. We also demonstrate in simulation experiments that our method outperforms prior works that use different RL algorithms or different approaches for predicting rewards. Project website: https://robofume.github.i

Illicit drug use and cerebral microbleeds in stroke and transient ischemic attack patients

Background: Cerebral microbleeds (CMB) signal cerebral small vessel disease and are associated with ischemic stroke (IS) incidence, recurrence, and complications. While illicit drug use (IDU) is associated with cerebral small vessel disease, the association between CMB and IDU is understudied. We sought to delineate differences in vascular risk factors between IDU and CMB and determine the effect of this relationship on outcomes in IS/transient ischemic attack (TIA) patients. Methods: We included 2001 consecutive IS and TIA patients (years 2009-2018) with a readable T2*gradient-echo MRI sequence. CMB rating followed standardized guidelines and CMB were grouped topographically into lobar, deep or infratentorial. IDU data (history and/or urine toxicology) was available for 1746 patients. The adverse composite outcome included pneumonia, urinary tract infection, deep venous thrombosis or death during hospitalization. Good functional outcome was defined as modified Rankin scale score < 3 and ambulatory on discharge. Univariate analysis was used to assess vascular risk factors and multivariable logistic regression was used to characterize the IDU/CMB relationship on outcomes. Results: We observed IDU in 13.8 % (n=241), and CMB in 32.9% (n=575, 53.8% lobar, 27.3% deep and 18.8% infratentorial). Patients with IDU and at least one CMB were older (53.6±10.5 vs. 56.9±11.5, p=0.04), had a lower BMI (28.1±5.9 vs. 26.6±4.4, p=0.04), and were more likely to have had a previous IS/TIA (25.1% vs. 41.9%, p=0.01). IDU trended higher for those with severe CMB (10+) compared with those without CMB and 1-9 CMB (25% [n=9] vs 14.3% [n=1171] and 12.1% [n=65] respectively; p=0.07) without individual drug deviations from this pattern. Adverse and good functional outcomes were observed in 177 and 905 total patients, respectively. No significant interaction was observed between IDU and CMB with either adverse or functional composite outcomes. Conclusion: IDU prevalence was high in our urban study population, and showed a borderline association with increasing CMB burden. Patients with CMB and IDU history were older and more likely to have had a previous IS/TIA. Further studies are required to clarify the clinical consequences related to the relationship between IDU and CMB.Author Disclosures: B. Petrie: None. H. Lau: None. F. Cajiga-Pena: None. S. Abbas: None. B. Finn: None. K. Dam: None. A. Cervantes-Arslanian: None. T.N. Nguyen: None. H. Aparicio: None. D. Greer: None. J.R. Romero: Speakers' Bureau; Modest; Received speaker honoraria from Ferrer Group

In vivo microdialysis reveals age-dependent decrease of brain interstitial fluid tau levels in P301S human tau transgenic mice

Although tau is a cytoplasmic protein, it is also found in brain extracellular fluids, e.g., CSF. Recent findings suggest that aggregated tau can be transferred between cells and extracellular tau aggregates might mediate spread of tau pathology. Despite these data, details of whether tau is normally released into the brain interstitial fluid (ISF), its concentration in ISF in relation to CSF, and whether ISF tau is influenced by its aggregation are unknown. To address these issues, we developed a microdialysis technique to analyze monomeric ISF tau levels within the hippocampus of awake, freely moving mice. We detected tau in ISF of wild-type mice, suggesting that tau is released in the absence of neurodegeneration. ISF tau was significantly higher than CSF tau and their concentrations were not significantly correlated. Using P301S human tau transgenic mice (P301S tg mice), we found that ISF tau is fivefold higher than endogenous murine tau, consistent with its elevated levels of expression. However, following the onset of tau aggregation, monomeric ISF tau decreased markedly. Biochemical analysis demonstrated that soluble tau in brain homogenates decreased along with the deposition of insoluble tau. Tau fibrils injected into the hippocampus decreased ISF tau, suggesting that extracellular tau is in equilibrium with extracellular or intracellular tau aggregates. This technique should facilitate further studies of tau secretion, spread of tau pathology, the effects of different disease states on ISF tau, and the efficacy of experimental treatments

A comprehensive assessment of measurement equivalence in operations management

This paper provides a comprehensive framework for treating equivalence both prior to data collection and during subsequent analyses, and assesses the extent to which equivalence is considered in survey research in six leading empirical Operations Management (OM) journals (Decision Sciences, International Journal of Operations & Production Management, International Journal of Production Research, Journal of Operations Management, Management Science and Production and Operations Management). Measurement equivalence of latent variables in survey data is an important condition that should be met in order to meaningfully pool and/or compare data stemming from apparently heterogeneous sub-groups. We assess 465 survey articles from a six-year period from 2006 to 2011 and document these articles in relation to the four main stages of our comprehensive framework: identifying sources of heterogeneity; maximising equivalence prior to data collection; testing measurement equivalence after data collection; and dealing with partial and non-equivalence. We conclude that pooling of data from heterogeneous sub-groups is common practice in OM, but that awareness and testing of equivalence remains limited. Given these findings, we further elaborate the best practices detected in those few OM studies that do address equivalence in some way. We conclude that to improve the quality of OM survey research, authors, editors and reviewers should pay greater attention to equivalence, and we provide a pragmatic checklist of measurement equivalence issues across the four stages

Analysis of Abrupt Transitions in Ecological Systems

The occurrence and causes of abrupt transitions, thresholds, or regime shifts between ecosystem states are of great concern and the likelihood of such transitions is increasing for many ecological systems. General understanding of abrupt transitions has been advanced by theory, but hindered by the lack of a common, accessible, and data-driven approach to characterizing them. We apply such an approach to 30–60 years of data on environmental drivers, biological responses, and associated evidence from pelagic ocean, coastal benthic, polar marine, and semi-arid grassland ecosystems. Our analyses revealed one case in which the response (krill abundance) linearly tracked abrupt changes in the driver (Pacific Decadal Oscillation), but abrupt transitions detected in the three other cases (sea cucumber abundance, penguin abundance, and black grama grass production) exhibited hysteretic relationships with drivers (wave intensity, sea-ice duration, and amounts of monsoonal rainfall, respectively) through a variety of response mechanisms. The use of a common approach across these case studies illustrates that: the utility of leading indicators is often limited and can depend on the abruptness of a transition relative to the lifespan of responsive organisms and observation intervals; information on spatiotemporal context is useful for comparing transitions; and ancillary information from associated experiments and observations aids interpretation of response-driver relationships. The understanding of abrupt transitions offered by this approach provides information that can be used to manage state changes and underscores the utility of long-term observations in multiple sentinel sites across a variety of ecosystems.Organismic and Evolutionary Biolog

Relativistic mechanics of neutron superfluid in (magneto) elastic star crust

At densities below the neutron drip threshold, a purely elastic solid model (including, if necessary, a frozen-in magnetic field) can provide an adequate description of a neutron star crust, but at higher densities it will be necessary to allow for the penetration of the solid lattice by an independently moving current of superfluid neutrons. In order to do this, the previously available category of relativistic elasticity models is combined here with a separately developed category of relativistic superfluidity models in a unified treatment based on the use of an appropriate Lagrangian master function. As well as models of the purely variational kind, in which the vortices flow freely with the fluid, such a master function also provides a corresponding category of non-dissipative models in which the vortices are pinned to the solid structure