cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Empowering WebAssembly with Thin Kernel Interfaces
Creators: name: Ramesh, Arjun
name: Huang, Tianshu
name: Titzer, Ben L.
name: Rowe, Anthony
Publisher: name: arXiv
Year: 2023
Subjects: subject: Operating Systems (cs.OS)
subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Wasm is gaining popularity outside the Web as a well-specified low-level binary format with ISA portability, low memory footprint and polyglot targetability, enabling efficient in-process sandboxing of untrusted code. Despite these advantages, Wasm adoption for new domains is often hindered by the lack of many standard system interfaces which precludes reusability of existing software and slows ecosystem growth.
 This paper proposes thin kernel interfaces for Wasm, which directly expose OS userspace syscalls without breaking intra-process sandboxing, enabling a new class of virtualization with Wasm as a universal binary format. By virtualizing the bottom layer of userspace, kernel interfaces enable effortless application ISA portability, compiler backend reusability, and armor programs with Wasm's built-in control flow integrity and arbitrary code execution protection. Furthermore, existing capability-based APIs for Wasm, such as WASI, can be implemented as a Wasm module over kernel interfaces, improving reuse, robustness, and portability through better layering. We present an implementation of this concept for two kernels -- Linux and Zephyr -- by extending a modern Wasm engine and evaluate our system's performance on a number of sophisticated applications which can run for the first time on Wasm.
description: This work is published at EuroSys 2025, Rotterdam, Netherlands (March 30 - April 3) 14 pages, 8 figures
Molecular Basis and Regulation of Ca2+ Release Termination and its Role in Cardiomyopathies
Creators: name: Liu, Yingjie
Publisher: name: Graduate Studies
Year: 2017
Subjects: subject: Biology--Cell
subject: Biology--Molecular
subject: Physiology
subject: FOS: Biological sciences
subject: Pharmacology

description: It is known that sarcoplasmic reticulum (SR) Ca2+ release in cardiac muscle is initiated via cardiac ryanodine receptor (RyR2) through a mechanism called Ca2+-induced Ca2+ release. However, how the SR Ca2+ release is terminated is undetermined. The objective of the current study is to understand the molecular basis and regulation of RyR2-mediated Ca2+ release termination and its role in the pathogenesis of cardiac diseases. Based on recent 3D structural analyses, the NH2-terminal region of RyR2 interacts with the channel domain via the central domain and undergoes dynamic conformational changes during channel gating. It has also been discovered that the NH2-terminal region consists of three distinct domains. HEK293 cell studies on domain deletions and disease mutations demonstrate that the different domains play different roles in RyR2 function. The NH2-terminal region is a major determinant of Ca2+ release activation and termination. Enhanced luminal Ca2+ activation of RyR2 has been linked to catecholaminergic polymorphic ventricular tachycardia (CPVT). However, in addition to CPVT, many RyR2 mutations can also cause cardiomyopathies. Knock-in mouse models harboring cardiomyopathy- associated RyR2 mutations have been generated to investigate the causal mechanisms of cardiomyopathies. The exon-3 deletion mouse model exhibited markedly reduced RyR2 expression level and no characteristic phenotype. The RyR2-R420W mouse model showed enhanced susceptibility to CPVT and altered cytosolic Ca2+ transient properties, suggesting that the abnormal cytosolic Ca2+ transient may be a key factor in the pathogenesis of cardiomyopathies. Calmodulin (CaM) is a regulatory protein that binds and inhibits RyR2 in the presence of cytosolic Ca2+. The inhibitory effect depends on the affinity of CaM for Ca2+ and RyR2. CaM mutations affecting either aspect may result in aberrant regulation of RyR2 activity, hence abnormal Ca2+ release termination. Indeed, arrhythmogenic mutations and most newly discovered CaM variants delayed Ca2+ release termination while others enhanced it, indicating that CaM is a major modulator of RyR2-mediated Ca2+ release termination. Overall, Ca2+ release termination is an intrinsic property of RyR2 that can be regulated by modulators such as CaM. Altered Ca2+ release termination is critically involved in the pathogenesis of cardiac diseases.
Ο ολικός χρόνος κολπικής αγωγής ως πιθανός δείκτης πρόβλεψης υποτροπής κολπικής μαρμαρυγής: μια Συστηματική Ανασκόπηση και Μετα-ανάλυση
Creators: name: Χιώτης Σωτήριος Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2023
Subjects: Ολικός χρόνος κολπικής αγωγής
Υπερηχογραφία
Κολπική μαρμαρυγή
Total atrial conduction time
Echocardiography
Atrial fibrillation

description: Σκοπός της διατριβής ήταν η μελέτη του χρόνου ολικής κολπικής αγωγής, μετρούμενο με ιστικό υπερηχογράφημα καρδιάς, ως προβλεπτικού δείκτη για την υποτροπή κολπικής μαρμαρυγής σε ασθενείς που υποβάλλονται σε έλεγχο ρυθμού. Παρουσιάσαμε τις τρέχουσες κατευθυντήριες οδηγίες για την διαχείριση της κολπικής μαρμαρυγής καθώς και τους χρησιμοποιούμενους δείκτες πρόβλεψης υποτροπής κολπικής μαρμαρυγής σε ασθενείς που υποβάλλονται σε καρδιοανάταξη και κατάλυση. Εξετάσαμε έναν νέο υπερηχογραφικό δείκτη, τον χρόνο ολικής κολπικής αγωγής και την προγνωστική επίδραση στην υποτροπή κολπικής μαρμαρυγής, διενεργώντας μια συστηματική ανασκόπηση και μετα-ανάλυση, και παρουσιάσαμε τα αποτελέσματα της μελέτης μας
description: The aim of the present thesis was the study of total atrial conduction time, measured with tissued doppler echocardiography, as a predictor of atrial fibrillation recurrence in patients under a rhythm control strategy. We presented current guidelines for the management of atrial fibrillation, as well as currently used predictors of atrial fibrillation recurrence after catheter ablation and cardioversion. We examined a novel echocardiographic marker, total atrial conduction time, and its prognostic effect in the recurrence of atrial fibrillation, by conducting a systematic review and meta-analysis, and we presented the results of our study
Sensitivity of interval Vp/Vs analysis of seismic data
Creators: name: Asuaje, Rafael
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Geology
subject: FOS: Earth and related environmental sciences
subject: Geophysics
subject: Vp/Vs
subject: Sensitivity
subject: Uncertainty

description: Three studies were conducted to evaluate the behavior of Vp/Vs ratio error in beds with different thickness. In the first study, a synthetic model was created to understand how the interval time would affect the calculation of the interval Vp/Vs and an equation was derived to estimate the percent error in the uncertainty of the ratio calculation. In a second study, the seismic data at Hussar, Alberta showed that Vp/Vs error increased as the analysis time window interval decreased. In addition, the percent error of the Vp/Vs values due to uncertainty was examined and it is suggested to use isochron intervals greater than 150 ms in PP time for robust results. Interval Vp/Vs analysis for data with intervals greater than this isochron have low uncertainty. In the third study, at Spring Coulee, Alberta, results showed that horizon pick adjustments can reduce error uncertainty by a small factor. In this and the previous studies, it was confirmed that beds with small thickness can have a significant impact on interval Vp/Vs uncertainties, which could lead to erroneous results. Additionally, all studies indicated that interpreters should work with bed intervals greater than 150 ms in PP times and perform horizon adjustments for more precise results.
Supernova 2000cb: high-energy version of SN 1987A
Creators: name: Utrobin, V. P.
name: Chugai, N. N.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Among type IIP supernovae there are a few events that resemble the well-studied supernova 1987A produced by the blue supergiant in the Large Magellanic Cloud. We study a peculiar supernova 2000cb and compare it with the supernova 1987A. We carried out hydrodynamic simulations of the supernova in an extended parameter space to describe its light curve and spectroscopic data. The hydrogen H-alpha and H-beta lines are modeled using a time-dependent approach. We constructed the hydrodynamic model by fitting the photometric and spectroscopic observations. We infer a presupernova radius of 35 Rsun, an ejecta mass of 22.3 Msun, an explosion energy of 4.4x10^{51} erg, and a radioactive Ni-56 mass of 0.083 Msun. The estimated progenitor mass on the main sequence lies in the range of 24-28 Msun. The early H-alpha profile on day 7 is consistent with the density distribution found from hydrodynamic modeling, while the H-alpha line on day 40 indicates an extended Ni-56 mixing up to a velocity of 8400 km/s. We emphasize that the dome-like light curves of both supernova 2000cb and supernova 1987A are entirely powered by radioactive decay. This is unlike normal type IIP supernovae, the plateau of which is dominated by the internal energy deposited after the shock wave propagation through the presupernova. We find signatures of the explosion asymmetry in the photospheric and nebular spectra. The explosion energy of supernova 2000cb is higher by a factor of three compared to supernova 1987A, which poses a serious problem for explosion mechanisms of type IIP supernovae.
description: one change made and one reference replaced
A New Old Idea: Beam-Steering Reflectarrays for Efficient Sub-THz Multiuser MIMO
Creators: name: Tiwari, Krishan Kumar
name: Caire, Giuseppe
Publisher: name: arXiv
Year: 2023
Subjects: subject: Signal Processing (eess.SP)
subject: Information Theory (cs.IT)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: We present a novel, power- & hardware-efficient, multiuser, multibeam RIS (Reflective Intelligent Surface) architecture for multiuser MIMO, especially for very high frequency bands (e.g., high mmWave and sub-THz), where channels are typically sparse in the beamspace and LOS is the dominant component. The key module is formed by an active multiantenna feeder (AMAF) with a small number of active antennas, placed in the near field of a RIS with a much larger number of passive controllable reflecting elements. We propose a pragmatic approach to obtain a steerable beam with high gain and very low sidelobes. Then K independently controlled beams can be achieved by closely stacking K such AMAF-RIS modules. Our analysis includes the mutual interference between the modules and the fact that, due to the delay difference of propagation through the AMAF-RIS structure, the resulting channel matrix is frequency selective even for pure LOS propagation. We consider a 3D geometry and show that "beam focusing" is in fact possible (and much more effective in terms of coverage) also in the far-field, by creating spotbeams with limited footprint both in angle and in range. Our results show that: 1) simple RF beamforming (BF) without computationally expensive baseband multiuser precoding is sufficient to practically eliminate multiuser interference when the users are chosen with sufficient angular/range separation, thanks to the extremely low sidelobe beams; 2) the impact of beam pointing errors with standard deviation as large as 2.5 deg and RIS quantized phase-shifters with quantization bits > 2 is essentially negligible; 3) The proposed architecture is more power efficient & much simpler from a hardware implementation viewpoint than standard active arrays with the same BF performance. We show also that the array gain of the proposed AMAF-RIS structure is linear with the RIS aperture.
description: 13 pages
Radiation Damping in the Photoionization of Fe^{14+}
Creators: name: Hasoglu, M. F.
name: Gorczyca, T. W.
name: Bautista, M. A.
name: Felfli, Z.
name: Manson, S. T.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: A theoretical investigation of photoabsorption and photoionization of Fe^{14+} extending beyond an earlier frame transformation R-matrix implementation is performed using a fully-correlated, Breit-Pauli R-matrix formulation including both fine-structure splitting of strongly-bound resonances and radiation damping. The radiation damping of $2p\rightarrow nd$ resonances gives rise to a resonant photoionization cross section that is significantly lower than the total photoabsorption cross section. Furthermore, the radiation-damped photoionization cross section is found to be in good agreement with recent experimental results once a global shift in energy of $\approx -3.5$ eV is applied. These findings have important implications. Firstly, the presently available synchrotron experimental data are applicable only to photoionization processes and not to photoabsorption; the latter is required in opacity calculations. Secondly, our computed cross section, for which the L-shell ionization threshold is aligned with the NIST value, shows a series of $2p \rightarrow nd$ Rydberg resonances that are uniformly 3-4 eV higher in energy than the corresponding experimental profiles, indicating that the L-shell threshold energy values currently recommended by NIST are likely in error.
description: 4 pages, 1 figures, and 2 tables
Flexible and Scalable Routing Approach for Mobile Ad Hoc Networks by Function Approximation of Q-Learning
Creators: name: Elzohbi, Mohamad
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Artificial Intelligence
subject: Computer Science
subject: Mobile ad hoc networks
subject: Reinforcement learning
subject: Q-learning
subject: Routing protocol
subject: Function approximation

description: Wireless mobile devices are rapidly spreading to the extent that it is hard to find a person not exposed to such technology. These devices could be connected directly or indirectly by wireless channels to form a mobile ad hoc network (MANET). Finding a route for flow from a source to a destination in a network is known as routing. Dynamic topology and unstable link states are the main problems facing routing in MANETs. This thesis employs reinforcement learning, namely Q-learning to develop a routing mechanism. Features inspired from the network are used in approximating the Q-function to form a new intelligent routing metric. This way, the routing process concentrates on specific routes instead of network-wide broadcasting. Accordingly, it is possible to achieve flexibility and scalability in routing. Advantages of the proposed routing technique have been highlighted by conducting experiments in two MANETs environments, namely hand-held devices based MANETs and VANETs.
Examining the Resilience, Attachment Styles, and Relationship Satisfaction of Adult Children of Alcoholics in Intimate Relationships
Creators: name: Young, Marley
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Educational Psychology
subject: Education--Guidance and Counseling
subject: Psychology--Clinical
subject: Psychology--Developmental
subject: Psychology--Social
subject: adult children of alcoholics
subject: Attachment Theory
subject: resilience
subject: relationship satisfaction

description: In conducting research with adult children of alcoholics (ACOAs) and comparing this population with adult children of non-alcoholics (ACONAs), the majority of studies have identified negative outcomes including increased mood disorders, substance abuse, and significantly more difficulties within interpersonal relationships. Although the majority of extant literature has focused research questions on the deficits that ACOAs manifest, a limited number of studies have found that certain ACOAs are able to adequately cope despite having experienced parental alcoholism. The purpose of the current research was to take a strengths-based approach in examining the resilience, attachment styles, and relationship satisfaction of ACOAs currently in intimate relationships, and gain additional understanding with regard to the resilience levels of ACOAs and their functioning within romantic relationships. Participants were 536 university students who completed a demographic questionnaire along with the Children of Alcoholics Screening Test, Experiences in Close Relationships Scale-Revised, Resilience Scale for Adults, and Couples Satisfaction Index. A quantitative research design was employed in order to examine group differences between ACOAs and ACONAs in terms of their levels of resilience, relationship satisfaction, and attachment styles, as well as a more detailed look at which dimensions of resilience may be associated with, and even predict, relationship satisfaction and attachment style. Results indicated that ACOAs reported lower levels of resilience and relationship satisfaction, as well as more insecure attachment styles within intimate relationships, than ACONAs. All resilience subscales were positively correlated with secure attachment and higher relationship satisfaction scores, while ACOAs who reported higher levels of resilience also reported significantly higher levels of relationship satisfaction and higher categorization of secure attachment style. Finally, regression analysis determined that the social resources resilience subscale was the only subscale able to predict higher relationship satisfaction scores and secure attachment categorization. Limitations to the study and potential clinical and research implications are discussed, and directions for future research are provided.
Some conjectures and results about multizeta values for F_q[t]
Creators: name: Rodríguez, José Alejandro Lara
Publisher: name: arXiv
Year: 2011
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11M38, 11M32

description: In this paper, we explain several conjectures about how a product of two Carlitz-Goss zeta values can be expressed as a F_p-linear combination of Thakur's multizeta values, generalizing the q=2 case dealt by D. Thakur in Relations between multizeta values for F_q[t]. In contrast to the classical sum shuffle, ζ(a)ζ(b)=ζ(a+b)+ζ(a,b)+ζ(b,a), the identities we get are much more involved. Hundreds of instances of these conjectures have been proved and we describe the proof method and the evidence.
description: 10 pages
Biocompatibility and degradation of the open-pored magnesium scaffolds LAE442 and La2
Creators: name: Kleer-Reiter, N.
name: Julmi, S.
name: Feichtner, F.
name: Waselau, A.-C.
name: Klose, C.
name: Wriggers, P.
name: Maier, H.J.
name: Meyer-Lindenberg, A.
Publisher: name: London : Inst. of Physics
Year: 2021
Subjects: subject: Biocompatibility
subject: Magnesium alloy
subject: Osseointegration
subject: Porous scaffold
subject: µCT
subject: Dewey Decimal Classification::600 | Technik::610 | Medizin, Gesundheit

description: Porous magnesium implants are of particular interest for application as resorbable bone substitutes, due to their mechanical strength and a Young’s modulus similar to bone. The objective of the present study was to compare the biocompatibility, bone and tissue ingrowth, and the degradation behaviour of scaffolds made from the magnesium alloys LAE442 (n = 40) and Mg-La2 (n = 40) in vivo. For this purpose, cylindrical magnesium scaffolds (diameter 4 mm, length 5 mm) with defined, interconnecting pores were produced by investment casting and coated with MgF2. The scaffolds were inserted into the cancellous part of the greater trochanter ossis femoris of rabbits. After implantation periods of 6, 12, 24 and 36 weeks, the bone-scaffold compounds were evaluated using ex vivo µCT80 images, histological examinations and energy dispersive x-ray spectroscopy analysis. The La2 scaffolds showed inhomogeneous and rapid degradation, with inferior osseointegration as compared to LAE442. For the early observation times, no bone and tissue could be observed in the pores of La2. Furthermore, the excessive amount of foreign body cells and fibrous capsule formation indicates insufficient biocompatibility of the La2 scaffolds. In contrast, the LAE442 scaffolds showed slow degradation and better osseointegration. Good vascularization, a moderate cellular response, bone and osteoid-like bone matrix at all implantation periods were observed in the pores of LAE442. In summary, porous LAE442 showed promise as a degradable scaffold for bone defect repair, based on its degradation behaviour and biocompatibility. However, further studies are needed to show it would have the necessary mechanical properties required over time for weight-bearing bone defects.
Examining the factors that influence successful participation in habitual physical activity of children and youth who are blind or visually impaired : a retrospective study
Creators: name: Devji, Sofeya
Publisher: name: University of British Columbia
Year: 2010

description: The purpose of this study was to explore the factors that have influenced successful participation in physical activity of school-aged children and youth who are blind or visually impaired. Data for this study were gathered through analysis of the personal narratives of four blind, physically active young adults (one active adult and three competitive athletes) as they reflected on key childhood and youth experiences that positively influenced their participation in physical activity. Using a socio-ecological framework, the study sought to map out, in detail, the individual and interconnected factors (e.g. family, teacher, peer attitudes) that influenced success within and across three different environments (family, school and community). The results found common themes across participant narratives indicating identifiable success factors related to the family and school environments. While individual themes emerged related to the community environment, they did not recur across the participant narratives. Interconnections among the three environments were similarly evident in individual participant narratives, but no recurring themes were found for this across participant narratives. Taken as a whole, the results present a holist perspective of the complex web of factors that have helped craft successful experiences and foster continued participation in physical activity for the individuals in this study.
Mapping the Shores of the Brown Dwarf Desert III: Young Moving Groups
Creators: name: Evans, Thomas M.
name: Ireland, Michael J.
name: Kraus, Adam L.
name: Martinache, Frantz
name: Stewart, Paul
name: Tuthill, Peter G.
name: Lacour, Sylvestre
name: Carpenter, John M.
name: Hillenbrand, Lynne A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We present the results of an aperture masking interferometry survey for substellar companions around 67 members of the young (~8-200Myr) nearby (~5-86pc) AB Doradus, Beta Pictoris, Hercules-Lyra, TW Hya, and Tucana-Horologium stellar associations. Observations were made at near infrared wavelengths between 1.2-3.8 microns using the adaptive optics facilities of the Keck II, VLT UT4, and Palomar Hale Telescopes. Typical contrast ratios of ~100-200 were achieved at angular separations between ~40-320mas, with our survey being 100% complete for companions with masses below 0.25\msolar across this range. We report the discovery of a $0.52 \pm 0.09$\msolar companion to HIP14807, as well as the detections and orbits of previously known stellar companions to HD16760, HD113449, and HD160934. We show that the companion to HD16760 is in a face-on orbit, resulting in an upward revision of its mass from $M_2 \sin i \sim 14$\mjupiter to $M_2 = 0.28 \pm 0.04$\msolar. No substellar companions were detected around any of our sample members, despite our ability to detect companions with masses below 80\mjupiter for 50 of our targets: of these, our sensitivity extended down to 40\mjupiter around 30 targets, with a subset of 22 subject to the still more stringent limit of 20\mjupiter. A statistical analysis of our non-detection of substellar companions allows us to place constraints on their frequency around ~0.2-1.5\msolar stars. In particular, considering companion mass distributions that have been proposed in the literature, we obtain an upper limit estimate of ~9-11% for the frequency of 20-80\mjupiter companions between 3-30AU at 95% confidence, assuming that their semimajor axes are distributed according to $d\mathcal{N}/da \propto a^{-1}$ in this range.
description: Accepted by ApJ
Ceria-Based Anodes for Next Generation Solid Oxide Fuel Cells
Creators: name: Mirfakhraei, Behzad
Publisher: name: Graduate Studies
Year: 2015
Subjects: subject: Chemistry--Physical
subject: Energy
subject: Materials Science
subject: Solid Oxide Fuel Cell
subject: Electrochemical Characterization
subject: H2S Poisoning
subject: Materials Synthesis
subject: SOFC Anode

description: Mixed ionic and electronic conducting materials (MIECs) have been suggested to represent the next generation of solid oxide fuel cell (SOFC) anodes, primarily due to their significantly enhanced active surface area and their tolerance to fuel components. In this thesis, the main focus has been on determining and tuning the physicochemical and electrochemical properties of ceria-based MIECs in the versatile perovskite or fluorite crystal structures. In one direction, BaZr0.1Ce0.7Y0.1M0.1O3-δ (M = Fe, Ni, Co and Yb) (BZCY-M) perovskites were synthesized using solid-state or wet citric acid combustion methods and the effect of various transition metal dopants on the sintering behavior, crystal structure, chemical stability under CO2 and H2S, and electrical conductivity, was investigated. BZCY-Ni, synthesized using the wet combustion method, was the best performing anode, giving a polarization resistance (RP) of 0.4 Ω.cm2 at 800 oC. Scanning electron microscopy and X-ray diffraction analysis showed that this was due to the exsolution of catalytic Ni nanoparticles onto the oxide surface. Evolving from this promising result, the effect of Mo-doped CeO2 (nCMO) or Ni nanoparticle infiltration into a porous Gd-doped CeO2 (GDC) anode (in the fluorite structure) was studied. While 3 wt. % Ni infiltration lowered RP by up to 90 %, giving 0.09 Ω.cm2 at 800 oC and exhibiting a ca. 5 times higher tolerance towards 10 ppm H2S, nCMO infiltration enhanced the H2S stability by ca. 3 times, but had no influence on RP. In parallel work, a first-time study of the Ce3+ and Ce4+ redox process (pseudocapacitance) within GDC anode materials was carried out using cyclic voltammetry (CV) in wet H2 at high temperatures. It was concluded that, at 500-600 oC, the Ce3+/Ce4+ reaction is diffusion controlled, probably due to O2- transport limitations in the outer 5-10 layers of the GDC particles, giving a very high capacitance of ca. 70 F/g. Increasing the temperature ultimately diminished the observed capacitance, likely as the chemical reduction of GDC at high temperatures is irreversible.
Identification of Existing Challenges and Future Trends for the Utilization of Ammonia-Water Absorption–Compression Heat Pumps at High Temperature Operation
Creators: name: Ahrens, Marcel Ulrich
name: Loth, Maximilian
name: Tolstorebrov, Ignat
name: Hafner, Armin
name: Kabelac, Stephan
name: Wang, Ruzhu
name: Eikevik, Trygve Magne
Publisher: name: Basel : MDPI
Year: 2021
Subjects: subject: Absorption–compression heat pump
subject: Ammonia-water
subject: High temperature heat pump
subject: Industrial heat pump
subject: Natural refrigerant
subject: Solution circuit
subject: Dewey Decimal Classification::600 | Technik

description: Decarbonization of the industrial sector is one of the most important keys to reducing global warming. Energy demands and associated emissions in the industrial sector are continuously increasing. The utilization of high temperature heat pumps (HTHPs) operating with natural fluids presents an environmentally friendly solution with great potential to increase energy efficiency and reduce emissions in industrial processes. Ammonia-water absorption–compression heat pumps (ACHPs) combine the technologies of an absorption and vapor compression heat pump using a zeotropic mixture of ammonia and water as working fluid. The given characteristics, such as the ability to achieve high sink temperatures with comparably large temperature lifts and high coefficient of performance (COP) make the ACHP interesting for utilization in various industrial high temperature applications. This work reviews the state of technology and identifies existing challenges based on conducted experimental investigations. In this context, 23 references with capacities ranging from 1.4 kW to 4500 kW are evaluated, achieving sink outlet temperatures from 45◦ C to 115◦ C and COPs from 1.4 to 11.3. Existing challenges are identified for the compressor concerning discharge temperature and lubrication, for the absorber and desorber design for operation and liquid–vapor mixing and distribution and the choice of solution pump. Recent developments and promising solutions are then highlighted and presented in a comprehensive overview. Finally, future trends for further studies are discussed. The purpose of this study is to serve as a starting point for further research by connecting theoretical approaches, possible solutions and experimental results as a resource for further developments of ammonia-water ACHP systems at high temperature operation.
Detection of Breathing Movements of Preterm Neonates by Recording Their Abdominal Movements with a Time-of-Flight Camera
Creators: name: Wiegandt, Felix C.
name: Biegger, David
name: Fast, Jacob F.
name: Matusiak, Grzegorz
name: Mazela, Jan
name: Ortmaier, Tobias
name: Doll, Theodor
name: Dietzel, Andreas
name: Bohnhorst, Bettina
name: Pohlmann, Gerhard
Publisher: name: Basel : MDPI
Year: 2021
Subjects: subject: Abdominal movement
subject: Optical detection of breathing movements
subject: Preterm neonate
subject: Time-of-flight camera
subject: Dewey Decimal Classification::600 | Technik::610 | Medizin, Gesundheit

description: In order to deliver an aerosolized drug in a breath-triggered manner, the initiation of the patient’s inspiration needs to be detected. The best-known systems monitoring breathing patterns are based on flow sensors. However, due to their large dead space volume, flow sensors are not advisable for monitoring the breathing of (preterm) neonates. Newly-developed respiratory sensors, especially when contact-based (invasive), can be tested on (preterm) neonates only with great effort due to clinical and ethical hurdles. Therefore, a physiological model is highly desirable to validate these sensors. For developing such a system, abdominal movement data of (preterm) neonates are required. We recorded time sequences of five preterm neonates’ abdominal movements with a time-of-flight camera and successfully extracted various breathing patterns and respiratory parameters. Several characteristic breathing patterns, such as forced breathing, sighing, apnea and crying, were identified from the movement data. Respiratory parameters, such as duration of inspiration and expiration, as well as respiratory rate and breathing movement over time, were also extracted. This work demonstrated that respiratory parameters of preterm neonates can be determined without contact. Therefore, such a system can be used for breathing detection to provide a trigger signal for breath-triggered drug release systems. Furthermore, based on the recorded data, a physiological abdominal movement model of preterm neonates can now be developed.
Development of a Multi-Frequency Adaptive Kalman Filter Based Tracking Loop for an Ionospheric Scintillation Monitoring Receiver
Creators: name: Ashwitha, Ashwitha
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Engineering--Electronics and Electrical
subject: GPS
subject: GNSS
subject: Kalman Filter
subject: Scintillation
subject: Adaptive
subject: Multi-Frequency
subject: Ionosphere

description: This thesis develops a combined GPS L1, L2C and L5 KF based tracking loop by exploiting the dispersive nature of the ionosphere and signal structure of the GPS signals. This results in a robust tracking loop suitable for a scintillation monitoring receiver. It also incorporates an adaptive algorithm that has adaptive bandwidth depending on scintillation level. Performance of combined KF based tracking algorithm compared with that of single frequency KF based tracking algorithm for both adaptive and non-adaptive cases are analysed and compared. A semi-analytic model is used to analyze the effect of scintillation on the tracking loop to perform faster and provide a reliable platform for analyzing the scintillation effects on the receiver performance. Results obtained from simulation data and real data show better performance for the adaptive multifrequency KF based tracking loop than that of the single frequency KF based tracking loop and the non-adaptive KF tracking loop.
European Starlings as Sentinels for Health Effects of Urban Air Pollution
Creators: name: North, Michelle Alison
Publisher: name: Graduate Studies
Year: 2017
Subjects: subject: Veterinary Science
subject: Public Health
subject: Toxicology
subject: air pollution
subject: air contaminants
subject: biomarkers
subject: ecotoxicology
subject: inhalation toxicology
subject: vehicle emissions
subject: Sturnus vulgaris

description: The consequences of exposure to air pollution are widely studied in humans, with urban pollutants associated with a suite of adverse health outcomes. With the complexity of air pollutant mixtures thwarting our full understanding of effects in humans, the consequences to urban wildlife are even less well-understood. The intricate, highly efficient respiratory system of birds makes them more sensitive to airborne toxicants than other vertebrates. The motivation for this study is to identify sensitive, reliable biomarkers of biological effects of air pollutants using wild European starlings (Sturnus vulgaris). This was achieved using two approaches: a field study investigation disclosed the effects of ambient exposure on nestling starlings, whereas experimental exposure of adult starlings to vehicle emissions provided insights under controlled conditions. In both studies, pollutant exposures were measured using several techniques to provide as accurate information as possible. Passive air samplers measured the concentrations of nitrogen dioxide, sulphur dioxide, and volatile organic compounds in ten urban parks in Calgary, Canada during May and June of 2013 to 2015, and during the experiment in May 2016. For the field study, the reproductive success of adult starlings, growth and development of their offspring, biomarkers of oxidative stress, hepatic detoxification effort, and T-cell mediated immune response were evaluated as biomarkers of contaminant effects. The relative contributions of confounding predictors were assessed, while clustering within nest and location were included during analyses. For the experimental study, the same biomarkers were measured in adult, wild-caught, non-breeding starlings, with additional measurements of B-cell immunity, thyroid hormones and histology. Several responses in nestlings indicated that higher exposures to benzene, toluene, ethylbenzene, xylenes (BTEX) and hexane had physiological costs, which, although subtle, may reduce the resilience of nestlings to cope with additional stressors such as fledging. Similarly, subclinical endocrine and immune changes in experimental birds suggest that higher exposures, or the exposure at sensitive life stages, may have population-level consequences.
Developing Porous Water Stable Metal Phosphonates for CO2 Capture Applications
Creators: name: Mah, Roger K
Publisher: name: Graduate Studies
Year: 2016
Subjects: subject: Chemistry--Inorganic
subject: Energy
subject: MOF
subject: CO2
subject: Capture
subject: Stability
subject: Porous
subject: Phosphonate

description: Porous solid sorbents have emerged as a promising class of materials for CO2 capture applications. A subclass of solid sorbents, metal-organic frameworks (MOFs), has been thoroughly investigated towards implementation into CO2 capture systems, owing to high tailorability from an inherently modular nature. The crux of conventional carboxylate-based MOFs has been stability against hydrolytic cleavage in the presence of elevated temperature and humidity. This thesis investigated the development of water stable phosphonate MOFs using the trigonal 1,3,5-tris(phosphonophenyl)benzene (H6L1) as the ligand coordinated to trivalent and tetravalent metals. The first metal investigated was Sn4+, which required significant efforts towards enhancing crystallinity. An ordered material for SnH2L1 (CALF-28) was achieved through solvothermal reaction followed a humidity exposure step. After the harsh humidity treatment, CALF-28 remained porous albeit with a decreased surface area. The second framework investigated utilized La3+ producing single crystals of LaH3L1 (CALF-29). Upon exposure to mild humidity treatment, CALF-29 decomposed resulting in significant loss of surface area revealing CALF-29 had no stability against hydrolytic cleavage. The final metal investigated with L1 was Zr4+ to produce ZrH2L1 (CALF-31). After repeated exposures to harsh humidity, CALF-31 remained porous with only a minor surface area drop. CALF-28 and CALF-31 were evaluated as potential CO2 capture sorbents and revealed the strengths of solid sorbents against the traditional monoethanolamine benchmark using calculations developed during this work. Finally, coordination of 1,3,5-tris(phosphonobiphenyl)benzene (H6L2) with Zr4+ provided insights into the effect of extending the L1 ligand. From the preliminary results, the potential advantages of H6L2, namely increased functionalization sites to accommodate polarizing groups, were discussed in the context of enhancing the CO2 capture potential of frameworks formed using trigonal trisphosphonates.
Learning and Processing over Networks (AMLD'19 workshop)
Creators: name: Defferrard, Michaël
name: Pena, Rodrigo
Publisher: name: Zenodo
Year: 2019

description: Slides presented during the Learning and Processing over Networks workshop at the Applied Machine Learning Days (AMLD). A github repository is available at https://github.com/rodrigo-pena/amld2019-graph-workshop.
A solid-fluid diffusionless reacting mixture theory model for bone
Creators: name: Cull, Stephen
Publisher: name: Graduate Studies
Year: 2012
Subjects: subject: Applied Mechanics
subject: Engineering--Mechanical
subject: mixture theory
subject: Growth
subject: Remodeling
subject: Bone

description: Mixture theory provides a framework to study materials composed of an arbitrary number of constituents. In addition to describing the motion and deformation of a material, mixture theory also describes reactions between constituents. The coupling of reactions and mechanical deformations for bone will be examined using a mixture theory approach. Bone will be considered as a reactive diffusionless solid-fluid mixture. Assumed evolution equations which depend on mechanical deformations will be used to describe reactions in bone. Considering a steady state biaxial stretch case and a uniaxial stress case, assumed evolution equations will be solved numerically. Results showed an increase of solid apparent density with increased mechanical loading. The precise relation between solid apparent density and mechanics depended on the choice of remodeling constants. In addition, the steady state orientation of a transversely isotropic solid constituent was determined to depend on the initial mixture composition.
Exceeding the threshold value for Trioza apicalis Förster 1848 in carrot fields did not cause damage as revealed during monitoring in Germany from 2017–2020
Creators: name: Sauer, J.
name: Dewert, A.
name: Hondelmann, P.
name: Meyhöfer, R.
name: Hommes, M.
name: Buck, H.
name: Ulrichs, C.
name: Vogler, U.
Publisher: name: Berlin ; Heidelberg : Springer
Year: 2021
Subjects: subject: Carrot psyllid Trioza apicalis
subject: Germany
subject: Insect pest
subject: Monitoring
subject: Organic carrots
subject: Dewey Decimal Classification::500 | Naturwissenschaften::580 | Pflanzen (Botanik)

description: The carrot psyllid Trioza apicalis Förster 1848 is a carrot pest in Europe that can cause serious damages in case of massive occurrence. Damages up to a total loss of yield have been reported from Scandinavian countries but also from Switzerland. The action threshold to control the pest with chemical pesticides is 0.2 T. apicalis per day and trap caught by sticky traps. We investigated the number of T. apicalis with sticky traps on carrot fields of the study regions Lüneburg/Uelzen and Hameln/Bad Pyrmont in Germany, during the period 2017–2020. The number of T. apicalis caught was generally very low in both study regions. On several fields in successive weeks almost no individuals were found in the study region Hameln/Bad Pyrmont. In Lüneburg/Uelzen was at least one field each year where the number of carrot psyllid was clearly higher than in all other fields and exceeded the threshold level. Surprisingly on carrot fields in close proximity to carrot fields from the previous year, the T. apicalis numbers were only slightly increased. Nonetheless, no loss of yield was reported for any of the fields in the four years of the study, although the generally defined threshold has been exceeded on many of the investigated carrot fields.
Structural and Biochemical Characterization of a Dye-Decolorizing Peroxidase from Dictyostelium discoideum
Creators: name: Rai, Amrita
name: Klare, Johann P.
name: Reinke, Patrick Y. A.
name: Englmaier, Felix
name: Fohrer, Jörg
name: Fedorov, Roman
name: Taft, Manuel H.
name: Chizhov, Igor
name: Curth, Ute
name: Plettenburg, Oliver
name: Manstein, Dietmar J.
Publisher: name: Basel : Molecular Diversity Preservation International
Year: 2021
Subjects: subject: B-type DyP
subject: Compound I
subject: Crystal structure
subject: Dictyostelium discoideum
subject: Dye-decolorizing-type peroxidase
subject: Electron paramagnetic resonance (EPR) spectroscopy
subject: Enzyme kinetics
subject: Heme peroxidases
subject: Lignin degradation
subject: Long-range electron transfer
subject: Dewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften, Biologie
subject: Dewey Decimal Classification::500 | Naturwissenschaften::540 | Chemie

description: A novel cytoplasmic dye-decolorizing peroxidase from Dictyostelium discoideum was investi-gated that oxidizes anthraquinone dyes, lignin model compounds, and general peroxidase substrates such as ABTS efficiently. Unlike related enzymes, an aspartate residue replaces the first glycine of the conserved GXXDG motif in Dictyostelium DyPA. In solution, Dictyostelium DyPA exists as a stable dimer with the side chain of Asp146 contributing to the stabilization of the dimer interface by extending the hydrogen bond network connecting two monomers. To gain mechanistic insights, we solved the Dicty-ostelium DyPA structures in the absence of substrate as well as in the presence of potassium cyanide and veratryl alcohol to 1.7, 1.85, and 1.6 Å resolution, respectively. The active site of Dictyostelium DyPA has a hexa-coordinated heme iron with a histidine residue at the proximal axial position and either an acti-vated oxygen or CN− molecule at the distal axial position. Asp149 is in an optimal conformation to accept a proton from H2O2 during the formation of compound I. Two potential distal solvent channels and a conserved shallow pocket leading to the heme molecule were found in Dictyostelium DyPA. Further, we identified two substrate-binding pockets per monomer in Dictyostelium DyPA at the dimer interface. Long-range electron transfer pathways associated with a hydrogen-bonding network that connects the substrate-binding sites with the heme moiety are described.
Secure estimation and control for cyber-physical systems under adversarial attacks
Creators: name: Fawzi, Hamza
name: Tabuada, Paulo
name: Diggavi, Suhas
Publisher: name: arXiv
Year: 2012
Subjects: subject: Optimization and Control (math.OC)
subject: Cryptography and Security (cs.CR)
subject: Information Theory (cs.IT)
subject: Systems and Control (eess.SY)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: The vast majority of today's critical infrastructure is supported by numerous feedback control loops and an attack on these control loops can have disastrous consequences. This is a major concern since modern control systems are becoming large and decentralized and thus more vulnerable to attacks. This paper is concerned with the estimation and control of linear systems when some of the sensors or actuators are corrupted by an attacker. In the first part we look at the estimation problem where we characterize the resilience of a system to attacks and study the possibility of increasing its resilience by a change of parameters. We then propose an efficient algorithm to estimate the state despite the attacks and we characterize its performance. Our approach is inspired from the areas of error-correction over the reals and compressed sensing. In the second part we consider the problem of designing output-feedback controllers that stabilize the system despite attacks. We show that a principle of separation between estimation and control holds and that the design of resilient output feedback controllers can be reduced to the design of resilient state estimators.
The world heritage Sundarbans mangrove forest in Bangladesh: ecosystem services and their linkage to poverty alleviation
Creators: name: Amalesh Dhar
name: Lael Parrott
Publisher: name: F1000 Research Limited
Year: 2019

description: The Sundarbans mangrove forest is one of the richest natural resource areas in Bangladesh. It represents one of the largest mangrove forests in the world and has been recognized as an internationally important World Heritage and Ramsar site. It plays a significant role for providing a wide range of floral and faunal biodiversity and ecosystem services (ES) that support livelihoods of local communities as well as economic progress of Bangladesh. Despite their importance to human well-being, such ES and natural capital, in general, is rarely tracked in national economic accounts and is unaccounted for in measures of economic progress. A range of historical data for ES and indicators of human wellbeing were used to describe the evolving trade-offs between ES and poverty of this area. The results reveal that non-timber forest products and fish production are the most highly valued provisioning services and directly linked to wellbeing of local people. As supporting service, habitat significantly contributes to conserve Bengal tiger and Irrawaddy dolphin populations and provide protection from cyclones. In addition, this forest could considerably contribute to poverty alleviation if the economic benefits could also be drawn from non-consumptive services like tourism, and carbon credits.
Gauge mediation to effective SUSY through U(1)s with a dynamical SUSY breaking, and string compactification
Creators: name: Jeong, Kwang Sik
name: Kim, Jihn E.
name: Seo, Min-Seok
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We investigate the possibility of U(1)' mediation, leading to an effective SUSY where the first two family sfermions are above 100 TeV but the third family sfermions and the Higgs doublets are in the TeV region(or the light stop case). The U(1)' gaugino, Zprimino, needs not to be at a TeV scale, but needs to be somewhat lighter than the messenger scale. We consider two cases, one the mediation is only through U(1)' and the other through U(1)' and the electroweak hypercharge U(1)_Y. In the SUSY field theory framework, we calculate the superpartner mass spectra for these two cases. We also point out that the particle species needed for these mechanisms are already obtained from a Z(12-I) orbifold compactification.