120 research outputs found
Medical Malpractice Litigation Under National Health Insurance: Essential or Expendable?
Identification of time-continuous models from sampled data is a long standing topic of discussion, and many approaches have been suggested. The Maximum Likelihood method is asymptotically and theoretically superior to other methods. However, it may suffer from numerical inaccuracies at fast sampling and it also requires reliable initial parameter values. A number of efficient and useful alternatives to the maximum-likelihood method have been developed over the years. The most important of these are State-Variable filters, combined with Instrumental Variable methods, including the simplified refined IV method. In this contribution we perform unpretentious numerical experiments to comment on these methods, and their mutual benefits.CADIC
Road mortality threatens small northern populations of the European pond turtle, Emys orbicularis
Little is known about road mortality and the effects to European pond turtle Emys orbicularis populations at the northern border of its range. Survival of the turtle populations in suboptimal conditions depends heavily on longevity, regular annual breeding and relatively large clutch sizes, but additional unnatural mortality could alter their survival rates. Loss of only single turtle in majority of northern populations could mean a loss of 3-20% of subpopulation. But due to comparative rarity of the road accidents the effects of individual road mortality to the turtle populations might not be recognized. We discuss possible effects of road–associated mortality, and suggest that precautionary measures as setting of the buffer zones with low road density and possibility of lowering of traffic volume must be considered during the planning of the species conservation actions
Fully Immersive Virtual Reality for Skull-base Surgery: Surgical Training and Beyond
Purpose: A virtual reality (VR) system, where surgeons can practice
procedures on virtual anatomies, is a scalable and cost-effective alternative
to cadaveric training. The fully digitized virtual surgeries can also be used
to assess the surgeon's skills using measurements that are otherwise hard to
collect in reality. Thus, we present the Fully Immersive Virtual Reality System
(FIVRS) for skull-base surgery, which combines surgical simulation software
with a high-fidelity hardware setup.
Methods: FIVRS allows surgeons to follow normal clinical workflows inside the
VR environment. FIVRS uses advanced rendering designs and drilling algorithms
for realistic bone ablation. A head-mounted display with ergonomics similar to
that of surgical microscopes is used to improve immersiveness. Extensive
multi-modal data is recorded for post-analysis, including eye gaze, motion,
force, and video of the surgery. A user-friendly interface is also designed to
ease the learning curve of using FIVRS.
Results: We present results from a user study involving surgeons with various
levels of expertise. The preliminary data recorded by FIVRS differentiates
between participants with different levels of expertise, promising future
research on automatic skill assessment. Furthermore, informal feedback from the
study participants about the system's intuitiveness and immersiveness was
positive.
Conclusion: We present FIVRS, a fully immersive VR system for skull-base
surgery. FIVRS features a realistic software simulation coupled with modern
hardware for improved realism. The system is completely open-source and
provides feature-rich data in an industry-standard format.Comment: IPCAI/IJCARS 202
The obesity paradox predicts the second wave of COVID-19 to be severe in western countries
Funding Information: This work was funded by the Latvian Council of Science grants lzp-2018/1-0393 (I.A.K.), lzp-2018/2-0057 (T.K.), and lzp-2020/2-0271 (T.K.). Publisher Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland.While COVID-19 infection and mortality rates are soaring in Western countries, Southeast Asian countries have successfully avoided the second wave of the SARS-CoV-2 pandemic despite high population density. We provide a biochemical hypothesis for the connection between low COVID-19 incidence, mortality rates, and high visceral adiposity in Southeast Asian populations. The SARS-CoV-2 virus uses angiotensin-converting enzyme 2 (ACE2) as a gateway into the human body. Although the highest expression levels of ACE2 are found in people’s visceral adipose tissue in Southeast Asia, this does not necessarily make them vulnerable to COVID-19. Hypothetically, high levels of visceral adiposity cause systemic inflammation, thus decreasing the ACE2 amount on the surface of both visceral adipocytes and alveolar epithelial type 2 cells in the lungs. Extra weight gained during the pandemic is expected to increase visceral adipose tissue in Southeast Asians, further decreasing the ACE2 pool. In contrast, weight gain can increase local inflammation in fat depots in Western people, leading to worse COVID-related outcomes. Because of the biological mechanisms associated with fat accumulation, inflammation, and their differential expression in Southeast Asian and Western populations, the second wave of the pandemic may be more severe in Western countries, while Southeast Asians may benefit from their higher visceral fat depots.publishersversionPeer reviewe
Improving Surgical Situational Awareness with Signed Distance Field: A Pilot Study in Virtual Reality
The introduction of image-guided surgical navigation (IGSN) has greatly
benefited technically demanding surgical procedures by providing real-time
support and guidance to the surgeon during surgery. \hi{To develop effective
IGSN, a careful selection of the surgical information and the medium to present
this information to the surgeon is needed. However, this is not a trivial task
due to the broad array of available options.} To address this problem, we have
developed an open-source library that facilitates the development of multimodal
navigation systems in a wide range of surgical procedures relying on medical
imaging data. To provide guidance, our system calculates the minimum distance
between the surgical instrument and the anatomy and then presents this
information to the user through different mechanisms. The real-time performance
of our approach is achieved by calculating Signed Distance Fields at
initialization from segmented anatomical volumes. Using this framework, we
developed a multimodal surgical navigation system to help surgeons navigate
anatomical variability in a skull base surgery simulation environment. Three
different feedback modalities were explored: visual, auditory, and haptic. To
evaluate the proposed system, a pilot user study was conducted in which four
clinicians performed mastoidectomy procedures with and without guidance. Each
condition was assessed using objective performance and subjective workload
metrics. This pilot user study showed improvements in procedural safety without
additional time or workload. These results demonstrate our pipeline's
successful use case in the context of mastoidectomy.Comment: First two authors contributed equally. 6 page
Medical Malpractice Litigation under National Health Insurance: Essential or Expendable?
Egalitarian mixed-species bird groups enhance winter survival of subordinate group members but only in high-quality forests
The Obesity Paradox Predicts the Second Wave of COVID-19 to Be Severe in Western Countries
While COVID-19 infection and mortality rates are soaring in Western countries, Southeast Asian countries have successfully avoided the second wave of the SARS-CoV-2 pandemic despite high population density. We provide a biochemical hypothesis for the connection between low COVID-19 incidence, mortality rates, and high visceral adiposity in Southeast Asian populations. The SARS-CoV-2 virus uses angiotensin-converting enzyme 2 (ACE2) as a gateway into the human body. Although the highest expression levels of ACE2 are found in people's visceral adipose tissue in Southeast Asia, this does not necessarily make them vulnerable to COVID-19. Hypothetically, high levels of visceral adiposity cause systemic inflammation, thus decreasing the ACE2 amount on the surface of both visceral adipocytes and alveolar epithelial type 2 cells in the lungs. Extra weight gained during the pandemic is expected to increase visceral adipose tissue in Southeast Asians, further decreasing the ACE2 pool. In contrast, weight gain can increase local inflammation in fat depots in Western people, leading to worse COVID-related outcomes. Because of the biological mechanisms associated with fat accumulation, inflammation, and their differential expression in Southeast Asian and Western populations, the second wave of the pandemic may be more severe in Western countries, while Southeast Asians may benefit from their higher visceral fat depots
Serotoninergic Modulation of Phototactic Variability Underpins a Bet-Hedging Strategy in Drosophila melanogaster
When organisms' environmental conditions vary unpredictably in time, it can be advantageous for individuals to hedge their phenotypic bets. It has been shown that a bet-hedging strategy possibly underlies the high inter-individual diversity of phototactic choice in Drosophila melanogaster. This study shows that fruit flies from a population living in a boreal and relatively unpredictable climate have more variable variable phototactic biases than fruit flies from a more stable tropical climate, consistent with bet-hedging theory. We experimentally show that phototactic variability of D. melanogaster is regulated by the neurotransmitter serotonin (5-HT), which acts as a suppressor of the variability of phototactic choices. When fed 5-HT precursor, boreal flies exhibited lower variability, and they were insensitive to 5-HT inhibitor. The opposite pattern was seen in the tropical flies. Thus, the reduction of 5-HT in fruit flies' brains may be the mechanistic basis of an adaptive bet-hedging strategy in a less predictable boreal climate
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