1,721 research outputs found
Feasibility of UV lasing without inversion in mercury vapor
We investigate the feasibility of UV lasing without inversion at a wavelength
of nm utilizing interacting dark resonances in mercury vapor. Our
theoretical analysis starts with radiation damped optical Bloch equations for
all relevant 13 atomic levels. These master equations are generalized by
considering technical phase noise of the driving lasers. From the Doppler
broadened complex susceptibility we obtain the stationary output power from
semiclassical laser theory. The finite overlap of the driving Gaussian laser
beams defines an ellipsoidal inhomogeneous gain distribution. Therefore, we
evaluate the intra-cavity field inside a ring laser self-consistently with
Fourier optics. This analysis confirms the feasibility of UV lasing and reveals
its dependence on experimental parameters.Comment: changes were made according to reviewer comments (accepted for
publication in JOSA B
Advice for lay callers with low-risk poison exposures by a regional poison control center: the impact on health care expenditures
Background: Since establishing the first poison control centers (PCCs), there is a still ongoing debate regarding their relevance and financing. The present study aims to analyze whether a regional PCC can reduce the economic burden associated with utilization of health care structures due to low-risk poison exposures on the German health care system.
Methods: A decision-tree based cost–benefit analysis comparing a situation utilizing PCC consultation versus a hypothetical situation without PCC consultation for low-risk poison exposures from the German health care system's perspective was conducted. The model inputs were obtained by a representative telephone survey of lay callers supplemented by empirical PCC and literature data. A probabilistic and deterministic sensitivity analysis with varying input variables was performed to prove the robustness of the findings.
Results: In the underlying telephone survey, data of 378 lay callers could be considered and included in the decision tree model. As a result, the mean costs for handling one low-risk poison exposure case were €41.99 utilizing PCC consultation compared to €145.92 without PCC consultation, indicating a cost–benefit ratio of 3.48 for the existence of the PCC. The sensitivity analysis proved that the outcome of the decision analysis does not change significantly with varying inputs.
Conclusion: The existence of PCCs relieve the burden on other health care providers and reduce health care costs to a relevant extent. Therefore, PCCs should be considered as an important supporting structure of the German health care system
Descriptive Cost-Effectiveness Analysis of a Counseling and Coordination Model in Psychosocial Care. Integration of Health Care and Social Rehabilitation
Introduction: A psychosocial outreach clinic was established to offer counseling and coordination of healthcare and complementary services for persons with psychosocial and mental problems. The cost-effectiveness of these services was measured based on a pre-post comparison.
Methods: A prospective observational study was conducted with clients of the outreach clinic. Data on resource consumption and quality of life were collected at baseline and follow-up after 3, 6, and 12 months using the Client Sociodemographic and Service Receipt Inventory to assess service utilization, and the 12-Item Short Form Health Survey to assess quality of life. The objective of the present analysis was to estimate the relation between monetary expenditure and QALYs (quality-adjusted life-years), before and after the outreach clinic was established, descriptively. The analysis was constructed from payer’s perspective and was supplemented by a sensitivity analysis.
Results: A total of 85 participants were included. Total annual expenditures before the intervention were 5,832 € per client for all service segments. During the 12-months study duration expenditures decreased to 4,350 € including the costs associated with outreach clinic services. QALYs for the 12-month study period were 0.6618 and increased about 0.0568 compared to the period before.
Discussion: Despite methodological limitations due to small sample size, a pre-post comparison and the retrospective cost data collection, this study suggests acceptability of the outreach clinic as cost-effective.
Conclusion: The activities of the outreach clinic as an integrated care model seem to be cost-effective regarding the relation between monetary expenditures and clients’ quality of life
Automatic analysis of systolic, diastolic and mean blood pressure of continuous measurement before, during and after sleep arousals in polysomnographic overnight recordings
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.This paper deals with a detailed examination of sleep arousal events and the corresponding changes of systolic, diastolic and mean blood pressure. Arousals are short awakening events during sleep which do not become noticeable for the sleeping person. But the organism increases vital parameters, e.g. the blood pressure. The recreative sleep is disturbed, and the risk factor for cardiovascular diseases rises significantly. Impact on the continuous measured blood pressure for two arousal groups named spontaneous and non spontaneous arousals will be investigated. Polysomnographic recordings of patients suffering from sleep apnoea and a healthy control group will be examined. Using averaged blood pressure curves and a high time resolution, the courses are investigated in more detail than before. The results show an increasing slope a few seconds before and possible pressure minima a few seconds after the beginning of the arousal.EC/FP6/018474-2/EU/Dynamic analysis of physiological Networks/Daphne
Automatic validation and quality based readjustment of manually scored EEG arousal
Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.A knowledge of arousals during sleep is important to attain a deeper understanding regarding cardiovascular diseases. Manual scoring is time consuming and not always accurate. Automatic approaches are even worse inter alia due to inaccurate learning data. This paper presents an algorithm to improve the accuracy of manually scored data. Also a measure of quality is introduced to judge the automatically estimated results.EC/FP6/018474-2/EU/Dynamic analysis of physiological Networks/Daphne
Office and ambulatory blood pressure control with a fixed-dose combination of candesartan and hydrochlorothiazide in previously uncontrolled hypertensive patients: results of CHILI CU Soon
Thomas Mengden1, Reinhold Hübner2, Peter Bramlage31Kerckhoff-Klinik GmbH, Bad Nauheim, 2Takeda Pharma GmbH, Aachen, 3Institut für Kardiovaskuläre Pharmakologie und Epidemiologie, Mahlow, GermanyBackground: Fixed-dose combinations of candesartan 32 mg and hydrochlorothiazide (HCTZ) have been shown to be effective in clinical trials. Upon market entry we conducted a noninterventional study to document the safety and effectiveness of this fixed-dose combination in an unselected population in primary care and to compare blood pressure (BP) values obtained during office measurement (OBPM) with ambulatory blood pressure measurement (ABPM).Methods: CHILI CU Soon was a prospective, noninterventional, noncontrolled, open-label, multicenter study with a follow-up of at least 10 weeks. High-risk patients aged ≥18 years with previously uncontrolled hypertension were started on candesartan 32 mg in a fixed-dose combination with either 12.5 mg or 25 mg HCTZ. OBPM and ABPM reduction and adverse events were documented.Results: A total of 4131 patients (52.8% male) with a mean age of 63.0 ± 11.0 years were included. BP was 162.1 ± 14.8/94.7 ± 9.2 mmHg during office visits at baseline. After 10 weeks of candesartan 32 mg/12.5 mg or 25 mg HCTZ, mean BP had lowered to 131.7 ± 10.5/80.0 ± 6.6 mmHg (P < 0.0001 for both comparisons). BP reduction was comparable irrespective of prior or concomitant medication. In patients for whom physicians regarded an ABPM to be necessary (because of suspected noncontrol over 24 hours), ABP at baseline was 158.2/93.7 mmHg during the day and 141.8/85.2 mmHg during the night. At the last visit, BP had significantly reduced to 133.6/80.0 mmHg and 121.0/72.3 mmHg, respectively, resulting in 20.8% being normotensive over 24 hours (<130/80 mmHg). The correlation between OBPM and ABPM was good (r = 0.589 for systolic BP and r = 0.389 for diastolic BP during the day). Of those who were normotensive upon OBPM, 35.1% had high ABPM during the day, 49.3% were nondippers, and 3.4% were inverted dippers. Forty-nine adverse events (1.19%) were reported, of which seven (0.17%) were regarded as serious.Conclusion: Candesartan 32 mg in a fixed-dose combination with either 12.5 mg or 25 mg HCTZ is safe and effective for further BP lowering irrespective of prior antihypertensive drug class not being able to control BP.Keywords: ambulatory blood pressure, office blood pressure, normalization, respons
Constrained-Differential-Kinematics-Decomposition-Based NMPC for Online Manipulator Control with Low Computational Costs
Flexibility combined with the ability to consider external constraints comprises the main advantages of nonlinear model predictive control (NMPC). Applied as a motion controller, NMPC enables applications in varying and disturbed environments, but requires time-consuming computations. Hence, given the full nonlinear multi-DOF robot model, a delay-free execution providing short control horizons at appropriate prediction horizons for accurate motions is not applicable in common use. This contribution introduces an approach that analyzes and decomposes the differential kinematics similar to the inverse kinematics method to assign Cartesian boundary conditions to specific systems of equations during the model building, reducing the online computational costs. The resulting fully constrained NMPC realizes the translational obstacle avoidance during trajectory tracking using a reduced model considering both joint and Cartesian constraints coupled with a Jacobian transposed controller performing the end-effector’s orientation correction. Apart from a safe distance from the obstacles, the presented approach does not lead to any limitations of the reachable workspace, and all degrees of freedom (DOFs) of the robot are used. The simulative evaluation in Gazebo using the Stäubli TX2-90 commanded of ROS on a standard computer emphasizes the significantly lower online computational costs, accuracy analysis, and extended adaptability in obstacle avoidance, providing additional flexibility. An interpretation of the new concept is discussed for further use and extensions
ExTRUST: Reducing Exploit Stockpiles with a Privacy-Preserving Depletion System for Inter-State Relationships
Cyberspace is a fragile construct threatened by malicious cyber operations of
different actors, with vulnerabilities in IT hardware and software forming the
basis for such activities, thus also posing a threat to global IT security.
Advancements in the field of artificial intelligence accelerate this
development, either with artificial intelligence enabled cyber weapons,
automated cyber defense measures, or artificial intelligence-based threat and
vulnerability detection. Especially state actors, with their long-term
strategic security interests, often stockpile such knowledge of vulnerabilities
and exploits to enable their military or intelligence service cyberspace
operations. While treaties and regulations to limit these developments and to
enhance global IT security by disclosing vulnerabilities are currently being
discussed on the international level, these efforts are hindered by state
concerns about the disclosure of unique knowledge and about giving up tactical
advantages. This leads to a situation where multiple states are likely to
stockpile at least some identical exploits, with technical measures to enable a
depletion process for these stockpiles that preserve state secrecy interests
and consider the special constraints of interacting states as well as the
requirements within such environments being non-existent. This paper proposes
such a privacy-preserving approach that allows multiple state parties to
privately compare their stock of vulnerabilities and exploits to check for
items that occur in multiple stockpiles without revealing them so that their
disclosure can be considered. We call our system ExTRUST and show that it is
scalable and can withstand several attack scenarios. Beyond the
intergovernmental setting, ExTRUST can also be used for other zero-trust use
cases, such as bug-bounty programs.Comment: 16 pages, 3 figures, IEEE Transactions on Technology and Societ
Position of the fluorescent label is a crucial factor determining signal intensity in microarray hybridizations
A key issue in applications of short oligonucleotide-based microarrays is how to design specific probes with high sensitivity. Some details of the factors affecting microarray hybridization remain unclear, hampering a reliable quantification of target nucleic acids. We have evaluated the effect of the position of the fluorescent label [position of label (POL)] relative to the probe-target duplex on the signal output of oligonucleotide microarrays. End-labelled single-stranded DNA targets of different lengths were used for hybridization with perfect-match oligonucleotide probe sets targeting different positions of the same molecule. Hybridization results illustrated that probes targeting the labelled terminus of the target showed significantly higher signals than probes targeting other regions. This effect was independent of the target gene, the fluorophore and the slide surface chemistry. Comparison of microarray signal patterns of fluorescently end-labelled, fluorescently internally random-labelled and radioactively end-labelled target-DNAs with the same set of oligonucleotide probes identified POL as a critical factor affecting signal intensity rather than binding efficiency. Our observations define a novel determinant for large differences of signal intensities. Application of the POL effect may contribute to better probe design and data interpretation in microarray applications
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