bluuebunny/crossref_metadata_2025 huggingface dataset:
Good vibrations: tactile cueing for freezing of gait in Parkinson’s disease
Authors: Klaver E. C. , van Vugt J. P. P. , Bloem B. R. , van Wezel R. J. A. , Nonnekes J. , Tjepkema-Cloostermans M. C.
Published: March 2023

Background

Cueing strategies can alleviate freezing of gait (FOG) in people with Parkinson’s disease (PD). We evaluated tactile cueing delivered via vibrating socks, which has the benefit of not being noticeable to bystanders.

Objective

To evaluate the effect of tactile cueing compared to auditory cueing on FOG.

Methods

Thirty-one persons with PD with FOG performed gait tasks during both ON and OFF state. The effect of open loop and closed loop tactile cueing, as delivered by vibrating socks, was compared to an active control group (auditory cueing) and to a baseline condition (uncued gait). These four conditions were balanced between subjects. Gait tasks were videotaped and annotated for FOG by two experienced raters. Motion data were collected to analyze spatiotemporal gait parameters. Responders were defined as manifesting a relative reduction of > 10% in the percent time frozen compared to uncued gait.

Results

The average percent time frozen during uncued gait was 11.2% in ON and 21.5% in OFF state. None of the three tested cueing modalities affected the percentage of time frozen in either the ON (p = 0.20) or OFF state (p = 0.12). The number of FOG episodes and spatiotemporal gait parameters were also not affected. We found that 22 out of 31 subjects responded to cueing, the response to the three types of cueing was highly individual.

Conclusions

Cueing did not improve FOG at the group level; however, tactile as well as auditory cueing improved FOG in many individuals. This highlights the need for a personalized approach when using cueing to treat FOG.
The efficacy and safety of corticosteroids in pediatric kidney scar prevention after urinary tract infection: a systematic review and meta-analysis of randomized clinical trials
Authors: Gkiourtzis Nikolaos , Glava Agni , Moutafi Maria , Vasileiadou Theopisti , Delaporta Theodora , Michou Panagiota , Printza Nikoleta , Makedou Kali , Tramma Despoina
Published: March 2023

Background

Acute pyelonephritis (APN) in pediatric patients may lead to kidney scarring and is one of the main causes of permanent kidney damage. The incidence of kidney scarring after one febrile urinary tract infection (UTI) is reported to range from 2.8 to 15%, with the percentage rising to 28.6% after ≥ 3 febrile UTIs. Corticosteroids may have a role in the reduction of kidney scar formation and urine cytokine levels. The possible benefit of adjuvant corticosteroid administration in the reduction of kidney scar formation in children with APN has been recently examined in randomized controlled trials (RCTs).

Objectives

The aim of this meta-analysis was to provide a summary of the current literature about the efficacy and safety of adjuvant corticosteroid administration in the reduction of kidney scar formation in children with APN.

Data sources

An extensive literature search through major databases (PubMed/MEDLINE and Scopus) was carried out for RCTs from inception until October 12, 2022, investigating the efficacy and safety of adjuvant corticosteroids in preventing kidney scarring in children with APN. A risk ratio with 95% CI was used for dichotomous outcomes.

Results

In total, 5 RCTs with 918 pediatric patients with APN were included in the study. Adjuvant corticosteroid treatment revealed a statistically significant reduction in kidney scarring (95% CI 0.42–0.95, p = 0.03), without increasing the risk of adverse events like bacteremia, prolonged hospitalization, or recurrence of UTI.

Limitations

There were limitations regarding sample size (n = 498 children), different classes of corticosteroids (methylprednisolone or dexamethasone), different routes of corticosteroid administration (intravenous or oral), and different day courses (3-day or 4-day course).

Conclusions

Adjuvant corticosteroid administration seems to have a beneficial effect on kidney scar reduction in children with APN. Future studies should focus on the evaluation of the efficacy and safety of corticosteroids in kidney scarring reduction after APN to strengthen the results of our study.

Graphical Abstract
„Digitale Einzelhandelsplattformen und städtische Akteur*innen – Kooperation als zukunftsfähiges Modell?“
Authors: Hardaker Sina , Appel Alexandra , Doll Paulina , Ströbel Kerstin
Published: March 2023

Vielerorts werden lokale Onlinemarktplätze ins Lebens gerufen, um innerstädtische Einzelhändler*innen vor dem Hintergrund des Strukturwandels, der coronabedingt verstärkt wurde, digital besser aufzustellen. Anhand eBay Deine Stadt, einer Initiative für lokale Onlinemarktplätze von eBay, die seit 2020 in Deutschland in bislang über 30 Städten und Regionen etabliert wurde, beleuchtet der Artikel die Strukturen und Akteur*innen, die an der Umsetzung der Initiative beteiligt sind. Auf Grundlage von Expert*inneninterviews mit einem von eBay für die Umsetzung beauftragten Beratungsunternehmen sowie kommunalen Akteur*innen werden erste Erfahrungen, Erwartungen und Kritikpunkte erhoben und diskutiert. Ziel ist es, eine anfängliche Evaluation des sich noch im Aufbau befindlichen lokalen Onlinemarktplatz-Programms eBay Deine Stadt durchzuführen. Dabei stehen insbesondere die Rolle eBays als Infrastrukturgeber und Kooperationspartner sowie die damit einhergehenden Prozesse, Probleme und Erwartungen im Vordergrund. Darauf basierend werden weiterführende Fragestellungen zu zukünftigen Dynamiken von Innenstädten identifiziert.
Predictive factors for respiratory failure and in-hospital mortality after surgery for spinal metastasis
Authors: Jaipanya Pilan , Lertudomphonwanit Thamrong , Chanplakorn Pongsthorn , Pichyangkul Picharn , Kraiwattanapong Chaiwat , Keorochana Gun , Leelapattana Pittavat
Published: March 2023

Purpose

Spinal metastasis surgeries carry substantial risk of complications. PRF is among complications that significantly increase mortality rate and length of hospital stay. The risk factor of PRF after spinal metastasis surgery has not been investigated. This study aims to identify the predictors of postoperative respiratory failure (PRF) and in-hospital death after spinal metastasis surgery.

Methods

We retrospectively reviewed consecutive patients with spinal metastasis surgically treated between 2008 and 2018. PRF was defined as mechanical ventilator dependence > 48 h postoperatively (MVD) or unplanned postoperative intubation (UPI). Collected data include demographics, laboratory data, radiographic and operative data, and postoperative complications. Stepwise logistic regression analysis was used to determine predictors independently associated with PRFs and in-hospital death.

Results

This study included 236 patients (average age 57 ± 14 years, 126 males). MVD and UPI occurred in 13 (5.5%) patients and 13 (5.5%) patients, respectively. During admission, 14 (5.9%) patients had died postoperatively. Multivariate logistic regression analysis revealed significant predictors of MVD included intraoperative blood loss > 2000 mL (odds ratio [OR] 12.28, 95% confidence interval [CI] 2.88–52.36), surgery involving cervical spine (OR 9.58, 95% CI 1.94–47.25), and ASA classification ≥ 4 (OR 6.59, 95% CI 1.85–23.42). The predictive factors of UPI included postoperative sepsis (OR 20.48, 95% CI 3.47–120.86), central nervous system (CNS) metastasis (OR 10.21, 95% CI 1.42–73.18), lung metastasis (OR 7.18, 95% CI 1.09–47.4), and postoperative pulmonary complications (OR 6.85, 95% CI 1.44–32.52). The predictive factors of in-hospital death included postoperative sepsis (OR 13.15, 95% CI 2.92–59.26), CNS metastasis (OR 10.55, 95% CI 1.54–72.05), and postoperative pulmonary complications (OR 9.87, 95% CI 2.35–41.45).

Conclusion

PRFs and in-hospital death are not uncommon after spinal metastasis surgery. Predictive factors for PRFs included preoperative comorbidities, intraoperative massive blood loss, and postoperative complications. Identification of risk factors may help guide therapeutic decision-making and patient counseling.
Estimated cumulative radiation exposure in patients treated for adolescent idiopathic scoliosis
Authors: Cool J. , Streekstra G. J. , van Schuppen J. , Stadhouder A. , van den Noort J. C. , van Royen B. J.
Published: March 2023

Purpose

Adolescent idiopoathic scoliosis (AIS) is a progressive spinal deformity, most often observed in female patients of pubescent age. The deformity’s severity, its progression through time, its treatment and subsequent follow-up are assessed with routine radiological evaluation of the patient’s full spine. This study aimed to determine the cumulative radiation exposure in average patients with AIS treated by brace or surgery throughout their treatment.

Methods

The average number of imaging procedures and corresponding radiation doses were retrospectively obtained from the medical charts of AIS patients treated conservatively and/or surgically at our institution. The median radiation exposure of all imaging modalities was stated in effective dose (mSv). The estimated cumulative effective radiation dose of the each treatment group was determined by multiplication of the average number of imaging conducted, and the median effective radiation dose per imaging modality.

Results

In total, 73 AIS patients were included (28 brace, 45 surgically). Patients treated with a brace were subjected to an average of 9.03 full spine radiographs, resulting in an estimated effective cumulative dose of 0.505 mSv over a median treatment period of 3.23 years. Patients treated surgically received an average of 14.29 full spine radiographs over a median treatment period of 2.76 years. The estimated effective cumulative dose amounted from 0.951 to 1.841 mSv, depending on the surgical technique.

Conclusion

The cumulative effective radiation doses rendered to AIS patients as part of their treatment and follow-up were relatively low. However, every exposure to ionising radiation for medical imaging purposes should be minimised.
Hugo Bondy (1900–1985): an Austrian scientist of mass spectrometry in the twentieth century
Authors: Schober Michael , Irrgeher Johanna , Prohaska Thomas
Published: March 2023

Hugo Bondy (1900–1985), a fairly unknown Austrian scientist working in academia in the twentieth century made important contributions to the development of double-focusing sector field mass spectrometers. This article describes his life and scientific contributions in a fascinating biography meriting his achievements in the development and construction of new mass spectrometers. The article divides into three sections according to Bondy’s biography. In the first section, his education, career in academia, and research in mass spectrometry are displayed. The second section reconstructs his expulsion from the university, his persecution and resistance in the Nazi era, and his failed attempt to be reinstated at his position as a scientist. In the third and last section, Bondy’s career in the Austrian Federal Ministry of Education is depicted by focusing on his youth work, a controversy of his political affiliations, and his accomplishments and character in the civil service. Bondy’s life is taken as an example to uncover the process of exclusion in science with all its consequences. But also, the ethical aspects of science for education and the application of a scientific attitude to society are revealed by his actions.

Graphical abstract
Hydrogeochemical evolution of the shallow and deep basaltic aquifers in Tamborine Mountain, Queensland (Australia)
Authors: Catania Sabrina T. , Reading Lucy
Published: March 2023

Tamborine Mountain, Queensland (Australia), is a prime example of a basalt fractured-rock aquifer. Yet very little is known about the hydrochemistry of this groundwater system. Both analytical (major ions and stable isotopes) and multivariate (hierarchical cluster analysis, principal component analysis and factor analysis) analyses were used in this study to investigate the factors that interact within this aquifer system, in order to determine groundwater hydrogeochemistry. A new approach was applied to the data by classifying hydrographs by water type to clearly identify differing aquifer zones. Three distinct groundwater chemistry types were identified, and they were differentiated by variations in depth. Shallow bores were dominated by Na–Cl waters, deep bores were dominated by Na–HCO3 and Ca–HCO3 waters, and the two deepest bores were dominated by mixed water types. The evaluation of hydrogeochemical data has determined that both mineral weathering processes and groundwater/surface-water interaction had a strong influence on the hydrogeochemistry. Seasonal effects were minimal in the study area based on physicochemical parameters and ion chemistry. However, stable isotopic data show temporal trends. Increased rainfall events during the wet season produced a depletion in δ18O and increased d-excess values. The opposite is found during the dry season as a result of higher evaporation rates that are not hindered by intense rainfall events.
Quality-adjusted time without symptoms or toxicity analysis of nivolumab plus chemotherapy versus chemotherapy alone for the management of previously untreated patients with advanced gastric cancer, gastroesophageal junction cancer, or esophageal adenocarcinoma
Authors: Lin Daniel , Nguyen Hiep , Shah Ruchit , Qiao Yao , Hartman John , Sugarman Ryan
Published: March 2023

Background

The phase 3 CheckMate 649 established superior overall survival of nivolumab in combination with chemotherapy (NIVO + chemo) compared with chemotherapy (chemo) alone as a first-line treatment for patients with Her2-negative advanced gastric cancer, gastroesophageal junction cancer, and esophageal adenocarcinoma (GC/GEJC/EAC). This post hoc trial analysis aimed to evaluate the benefit of NIVO + chemo using quality-adjusted time without symptoms or toxicity (Q-TWiST) to further account for quality of life (QoL) in different health states depending on disease progression and treatment toxicity.

Methods

Using data from CheckMate 649, we evaluated the quality-adjusted survival gain associated with NIVO + chemo compared with chemo alone among all randomized patients and repeated similar analyses among those with programmed cell death-ligand 1 (PD-L1) combined positive score (CPS) ≥ 5. Relative Q-TWiST gains of ≥ 10% were predefined as clinically important.

Results

In all randomized patients, those receiving NIVO + chemo had a mean Q-TWiST gain of 1.8 (95% CI 0.9, 2.7) months compared with those receiving chemo alone. The relative Q-TWiST gain was estimated to be 12.8%. Patients with PD-L1 CPS ≥ 5 had greater quality-adjusted survival gain from NIVO + chemo with an estimated Q-TWiST gain of 2.8 (95% CI 1.5, 4.1) months, representing a relative gain of 20.6%. Subgroup analyses and sensitivity analyses with various QoL utility values yielded consistent findings in favor of NIVO + chemo compared with chemo alone. Q-TWiST gain from NIVO + chemo increased with longer duration of follow-up.

Conclusions

NIVO + chemo was associated with a statistically significant and clinically important gain in quality-adjusted survival compared with chemo alone among previously untreated patients with advanced GC/GEJC/EAC.
Absence of song suggests heterogeneity of vocal-production learning in hummingbirds
Authors: Monte Amanda , da Silva Maria Luisa , Gahr Manfred
Published: March 2023

Hummingbirds have been recognized, along with songbirds and parrots, as capable of learning songs. However, it is still unclear whether singing can be treated as a homologous trait within the family, analogous to songbirds. Therefore, we systematically compared the information about hummingbird vocalizations in the literature in a phylogenetic framework. In general, songs were emitted by perching males in a reproductive context, while calls were mainly in agonistic contexts. Singing was ancestral in most of the nine major hummingbird clades, but has been lost at least once in the mountain gem clade and twice in the bee clade. This evolutionary loss of singing might suggest heterogeneity of vocal-production learning.
Simulation of blind pre-diction and post-diction shaking table tests on a masonry building aggregate using a continuum modelling approach
Authors: Aşıkoğlu Abide , D’Anna Jennifer , Ramirez Rafael , Solarino Fabio , Romanazzi Antonio , Ciocci Maria Pia , Bianchini Nicoletta
Published: March 2023

Masonry buildings of historical centres are usually organized within aggregates, whose structural performance against seismic actions is challenging to predict and constitutes still an open issue. The SERA—AIMS (Seismic Testing of Adjacent Interacting Masonry Structures) project was developed to provide additional experimental data by testing a half-scale, two-unit stone masonry aggregate subjected to two horizontal components of dynamic excitation. In this context, this paper investigates the reliability of the modelling approach and the assumptions adopted to generate a three-dimensional continuum finite element model. The work involves two stages, namely a blind pre-diction and a post-diction phase, and proposes a series of simulation analyses including a strategy to shorten the actual records and save computation costs. The study was performed to investigate the extent of uncertainty in modelling for such masonry aggregates in relation to the experimental outcomes. Pre-diction results were proven to be not accurate in terms of predicted displacements and damage patterns. The upgrades introduced for the post-diction analyses, including the calibration of the elastic modulus and the introduction of a non-linear interface between the two units, allowed to improve the outcomes, with reasonable results in terms of predicted base shear force, displacements along Y-direction and damage pattern for the non-linear stage. The overall approach showed to be appropriate for the structural analysis of existing masonry aggregates, but the accurate modelling of this type of structure remains challenging due to the high level of uncertainties.
Event-Driven Serverless Pipelines for Video Coding and Quality Metrics
Authors: Moina-Rivera Wilmer , Garcia-Pineda Miguel , Claver Jose M. , Gutiérrez-Aguado Juan
Published: March 2023

Nowadays, the majority of Internet traffic is multimedia content. Video streaming services are in high demand by end users and use HTTP Adaptive Streaming (HAS) as transmission protocol. HAS splits the video into non-overlapping chunks and each video chunk can be encoded independently using different representations. Therefore, these encode tasks can be parallelized and Cloud computing can be used for this. However, in the most extended solutions, the infrastructure must be configured and provisioned in advance. Recently, serverless platforms have made posible to deploy functions that can scale from zero to a configurable maximum. This work presents and analyses the behavior of event-driven serverless functions to encode video chunks and to compute, optionally, the quality of the encoded videos. These functions have been implemented using an adapted version of embedded Tomcat to deal with CloudEvents. We have deployed these event-driven serverless pipelines for video coding and quality metrics on an on-premises serverless platform based on Knative on one master node and eight worker nodes. We have tested the scalability and resource consumption of the proposed solution using two video codecs: x264 and AV1, varying the maximum number of replicas and the resources allocated to them (fat and slim function replicas). We have encoded different 4K videos to generate multiple representations per function call and we show how it is possible to create pipelines of serverless media functions. The results of the different tests carried out show the good performance of the serverless functions proposed. The system scales the replicas and distributes the jobs evenly across all the replicas. The overall encoding time is reduced by 18% using slim replicas but fat replicas are more adequate in live video streaming as the encoding time per chunk is reduced. Finally, the results of the pipeline test show an appropriate distribution and chaining among the available replicas of each function type.
María Teresa Miras Portugal: a pioneer in the study of purinoceptors in chromaffin cells
Authors: Artalejo Antonio R. , Arribas-Blázquez Marina , Barahona María Victoria , Llorente-Sáez Celia , Olivos-Oré Luis Alcides
Published: March 2023

María Teresa Miras Portugal devoted most of her scientific life to the study of purinergic signalling. In an important part of her work, she used a model system: the chromaffin cells of the adrenal medulla. It was in these cells that she identified diadenosine polyphosphates, from which she proceeded to the study of adrenomedullary purinome: nucleotide synthesis and degradation, adenosine transport, nucleotide uptake into chromaffin granules, exocytotic release of nucleotides and autocrine regulation of chromaffin cell function via purinoceptors. This short review will focus on the current state of knowledge of the purinoceptors of adrenal chromaffin cells, a subject to which María Teresa made seminal contributions and which she continued to study until the end of her scientific life.
Studies on Argentine Phylacia species (Hypoxylaceae) using a polythetic taxonomic approach
Authors: Lambert Christopher , Schiefelbein Rahel , Jaimez Javier A. , Stadler Marc , Sir Esteban B.
Published: March 2023

The current study is dedicated to the taxonomy of the genus Phylacia (Hypoxylaceae) in Argentina. Fieldwork in the north of the country provided several fresh collections that were studied, using a polyphasic approach. The secondary metabolite profiles of the specimens were generated by high-performance liquid chromatography hyphenated by diode array and mass spectrometry (HPLC–DAD/MS) of the stromata. This study confirmed the presence of secondary metabolites that are also found in the related genus Daldinia. The detection of binapththalene tetrol (BNT), daldinal B, and daldinol, which are also characteristic of certain species of Daldinia and Hypoxylon, further confirmed the chemotaxonomic affinities within the Hypoxylaceae. The phylogenetic affinities of several species were determined using a multi-gene genealogy based on ITS, LSU, TUB2, and RPB2 sequences, confirming that Phylacia is most closely related to Daldinia, Rhopalostroma, and Thamnomyces. The new species P. lobulata, which features a rather unique stromatal morphology and seems to exhibit apparent host specificity for the endemic tree Pseudobombax argentinum, is described.
E-commerce channel management on the manufacturers’ side: ongoing debates and future research pathways
Authors: Ballerini Jacopo , Yahiaoui Dorra , Giovando Guido , Ferraris Alberto
Published: March 2023

Since the beginning of the 2000s, online commerce has been gradually taking over and shaping the global marketplace. This has led several scholars to study the phenomenon from different angles, from consumer habits to privacy risks to related technological innovations. However, only recently has a branch of literature addressing the online channel management phenomenon from the manufacturers’ perspective emerged. This rapidly expanding literature strand remains rather fragmented, raising the need for a systematic literature review to comprehensively structure and discuss it. This study, accordingly, proposes a systematic literature review on online channel management from the manufacturers’ perspective. Firstly, it provides relevant bibliometric insights into the ongoing research on the topic. Secondly, applying the bibliographic coupling methodology individuates 92 interconnected contributions published by 31 December 2021. Three different, albeit interconnected, thematic clusters are discovered and reviewed, revealing their focus on (a) strategic marketing issues around manufacturervsretailer conflict, (b) pricing policies and trade-offs among pricevsservices, and (c) operational interactions and strategies between supply chain members. Finally, after a systematic literature review the authors develop thirteen original research propositions concerning new research pathways and theoretical advancements to be designed and implemented.
Meeting the challenges of wild boar hunting in a modern society: The case of France
Authors: Vajas Pablo , Von Essen Erica , Tickle Lara , Gamelon Marlène
Published: March 2023

Modern hunting is an ambivalent practice, torn between leisure and labor. Nowhere are these conflicting dimensions better manifested than for wild boar—a simultaneous game and pest species in many countries. Here, we consider the sociological, political and cultural phenomenon of wild boar hunting from a change perspective, starting at its historical roots to future implications concerning the changing demographics, drivers, needs and practices of a modernizing hunting community. Using the case context of France, we present an approach to deconstructing each component of wild boar hunting firstly, and subsequently the external forces that change the nature of hunting. The objective of this manuscript is to discuss of the wild boar optimal harvesting to be applied in changing social and ecological environment. Findings show that the challenges facing wild boar management will likely intensify in the future, especially under the spotlight of a controversial public debate.
Differentiation of integral Mittag-Leffler and integral Wright functions with respect to parameters
Authors: Apelblat Alexander , González-Santander Juan Luis
Published: March 2023

Derivatives with respect to the parameters of the integral Mittag-Leffler function and the integral Wright function, recently introduced by us, are calculated. These derivatives can be expressed in the form of infinite sums of quotients of the digamma and gamma functions. In some particular cases, these infinite sums are calculated in closed-form with the help of MATHEMATICA. However, parameter differentiation reduction formulas are explicitly derived in order to check some of the results given by MATHEMATICA, as well as to provide many other new results. In addition, we present these infinite sums graphically for particular values of the parameters. Finally, new results for parameter derivatives of the Mittag-Leffler and Wright functions are reported in the Appendices.
Particle Number Emission for Periodic Technical Inspection in a Bus Rapid Transit System
Authors: Botero Maria L. , Londoño Javier , Agudelo Andrés F. , Agudelo John R.
Published: March 2023

This study was carried out under the Climate and Clean Air in Latin American Cities program (CALAC+) and aimed to evaluate the particle-number-based periodic technical inspection (PN-PTI) test in a public bus rapid transport (BRT) system and establish a baseline of PN emission. The PN-PTI test was performed in 1474 buses with emission standards from Euro II to Euro V without diesel particle filter (DPF), Euro V with retrofitted DPF, Euro VI diesel with original engine manufacturer DPF, and compressed natural gas (CNG) fueled. The median PN emission of buses with DPF is below 3000 #/cm3. PN emission limits such as 1,000,000 #/cm3 or 250,000 #/cm3 would allow the approval of vehicles with DPF that are not fully operational. An additional high-idle test is proposed for buses with emissions above 50,000 #/cm3, but below the test approval limit, to detect DPF that may require maintenance.For buses without DPF, which are the majority of the bus fleets in Latin America, the PN emission test can detect and target very-high emitters for developing special policies. CNG buses presented the lowest emissions, likely because of the detection limit of the equipment (23 nm) which cannot detect the large number of particles emitted by these vehicles in the sub-23 nm particle range.
Virtuelle Flurgespräche und Status-Updates: Zusammenarbeit in avatar-basierten Arbeitsumgebungen
Authors: Oehring Felix , Feufel Markus A. , Mörike Frauke
Published: March 2023

Der vorliegende Beitrag beschäftigt sich mit der Zusammenarbeit von hybrid arbeitenden Teams in avatar-basierten virtuellen Büroumgebungen. Ausgehend von den drei Dimensionen der Virtualität gehen wir folgenden Forschungsfragen nach: (1) Wie wird der Arbeitsalltag und die Zusammenarbeit in diesen Umgebungen koordiniert? und (2) Welche Vorteile und Herausforderungen sehen Nutzer*innen in Bezug auf avatar-basierte Arbeitsumgebungen? Auf Basis einer multi-methodischen Studie bestehend aus qualitativen Interviews mit erfahrenen Nutzer*innen und einer partizipativen Fokusgruppendiskussion mit neuen Nutzer*innen zeigen wir, dass Zusammenarbeit in avatar-basierten Arbeitsumgebungen in vielfältigen Arbeitsformen – von Ko-Präsenz bis zum mobilem Arbeiten – stattfindet und dass für die Koordination dieser Arbeitsmodi vielversprechende Ansätze zur Verfügung stehen. Unsere Ergebnisse zeigen aber auch, dass für die Ausschöpfung dieses Potentials nicht nur die virtuellen Umgebungen selbst, sondern auch die kollaborativen Arbeitsformen und die digitale Infrastruktur von Teams konsequent weiterentwickelt werden müssen.

Praktische Relevanz: Die Studie untersucht Virtualität anhand einer aktuell nutzerbaren, avatar-basierten Arbeitsumgebung und zeigt die Perspektiven erfahrener und neuer Nutzer*innen auf Zusammenarbeit innerhalb dieses soziotechnischen Arbeitssystems auf. Insbesondere werden konkrete kollaborative Arbeitspraktiken vorgestellt und deren Herausforderungen diskutiert, um potenziellen Nutzer*innen, die virtuelle Arbeitsumgebungen selbst anwenden möchten, eine Orientierung zu bieten.
Geburtshilfliche Blutungen
Authors: Dadak Christian
Published: March 2023

Blutungen zählen zu den häufigsten Todesursachen von Frauen während der Schwangerschaft und innerhalb des darauffolgenden Jahrs. Dies gilt für die industrialisierte Welt, aber ganz besonders für Länder mit niedrigem Einkommensschnitt. Die meisten mütterlichen Todesfälle wären vermeidbar.
Role of silt and clay fractions in organic carbon and nitrogen stabilization in soils of some old fruit orchards in the Nile floodplain, Sohag Governorate, Egypt
Authors: Thabit Fatma N. , El-Shater Abdel-Hamid , Soliman Wafaa
Published: March 2023

Purpose

Study the effect of both silt and clay fractions on stabilizing organic carbon and total nitrogen in soils of some old cultivated fruit orchards in Sohag, Egypt.

Methods

Eleven surface soil samples (0–15 cm) were collected. Silt (63–2 μm) and clay (< 2 μm) fractions were separated from soils and analyzed for cation exchange capacity (CEC), organic carbon (OC), total nitrogen (TN), specific surface area (SSA), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopic analysis were determined using the standard analysis methods.

Results

The silt and clay were responsible for 77.49 to 93.34% of soil CEC. The SSA of clay was twice the silt, and the phyllosilicates (%) average was 29.83% and 62.70% in silt and clay. Other minerals, such as quartz, feldspar, and carbonate minerals, were detected in these fractions. The phyllosilicate species of clay were smectite-illite mixed layers (44.4–88.9%), Smectite (1.0–6.4% except one sample recorded 45.7%), Kaolinite (3.7–10.5%) and kaolinite/smectite mixed layers (2.0–8.2%). The average OC-silt and clay were 6.79 and 8.96 g OC kg−1 soil (38.01 and 50.28% of soil OC). On average, the total nitrogen (TN) in silt and clay particles was 0.817 and 1.156 g N kg−1 soil (35.88 and 50.66% of soil TN). The OC and N content significantly and positively correlated with CEC, SSA, and phyllosilicates in the fine fractions.

Conclusion

Results showed that the soil's capacity to sequester OC and N is affected significantly by its fine particles' content, characteristics, and mineralogy.
Amphetamine-induced prolonged disturbances in tissue levels of dopamine and serotonin in the rat brain
Authors: Taracha Ewa , Czarna Magdalena , Turzyńska Danuta , Maciejak Piotr
Published: March 2023

Background

A hallmark of psychostimulants is the persistence of neurobiological changes they produce. The difficulty in reversing long-time effects of psychostimulants use is why addiction therapy is so ineffective. This study aimed to look for such drug-induced changes that can be detected even after many weeks of abstinence.

Methods

Rats were given 12 doses of amphetamine (Amph) at 1.5 mg/kg. The rewarding effect of Amph was assessed using ultrasonic vocalization. After 14 and 28 days of abstinence, tissue levels of dopamine (DA), serotonin (5-HT), and their metabolites were measured in the prefrontal cortex (PFC), nucleus accumbens (Acb), dorsomedial (CPuM), and dorsolateral (CPuL) striatum.

Results

After 28 days of abstinence, DA levels were increased in the dorsal striatum while 5-HT levels were decreased in all brain regions studied. The opposite direction of changes in DA and 5-HT tissue levels observed in the dorsal striatum may be related to the changes in the emotional state during abstinence and may contribute to the incubation of craving and relapses. Tissue levels of 5-HT and DA showed intra- and inter-structural correlations, most pronounced after 14 days of abstinence. Most of them were absent in the control group (ctrl), which may indicate that their appearance was related to the changes induced by earlier Amph administration. We did not find any associations between reward sensitivity and the persistence of Amph-induced neurochemical disturbances.

Conclusions

Administration of 12 moderate doses of Amph causes prolonged changes in DA and 5-HT tissue levels. The direction and severity of the changes are dependent on the brain region and the neurotransmitter studied.
ECRA thruster advances: 30W and 200W prototypes latest performances
Authors: Désangles Victor , Packan Denis , Jarrige Julien , Peterschmitt Simon , Dietz Patrick , Scharmann Steffen , Holste Kristof , Klar Peter J
Published: March 2023

The H2020 MINOTOR project focused on the study and the optimization of the ECRA thruster, an electric propulsion system for satellites. First, a 30 W prototype of this Electron Cyclotron Resonance Thruster (ECRT) is optimized. Then, a 200 W prototype is design based on these findings. The performances of both prototypes were assessed at two different facilities: at ONERA in France and at Justus Liebig University in Germany. Significant improvement of performances of both thrusters with the decrease of background pressure is presented. Total thrust efficiencies as high as 50% are measured at JLU, as well as erosion and lifetime assessment. The stability of the thruster for a constant point of operation was measured for one hundred hours of operation.
Competitive programming participation rates: an examination of trends in U.S. ICPC regional contests
Authors: Blum Jeremy J.
Published: March 2023

A wide range of benefits have been posited from participation in competitive programming contests. However, an analysis of participation in north American regional contests in the International Collegiate Programming Contest (ICPC) shows that participation in these contests is sharply declining, coinciding with the COVID-19 pandemic. Moreover, prior to the pandemic, while the number of teams participating in regional contests was increasing, the number of institutions sending teams to these contests was declining. We find several statistically significant correlations that may underscore structural reasons for this trend. Consistent participation in contests and the number of teams per institution sent to a contest both are correlated with likely participation in future contests. On the other end of the spectrum, institutions sending a team to a contest for the first time in 3 years were much less likely to return in the next year. For this category of teams, if a team is unable to solve any problems in the contest, the institution is significantly less likely to send a team in the next year. Many of these contests have very challenging problem sets, and consequently, have many teams that fail to solve any problems. This result suggests that structuring the problem sets to increase the likelihood that most teams successfully complete problems would broaden participation in these contests.
The Sovereign Lender of Last Resort Role of the ECB: Rules, Choice, and Time
Authors: Quinn David
Published: March 2023

This article argues that the European Central Bank (ECB), supported by the Court of Justice of the European Union (CJEU), can be perceived to have functionally softened the no sovereign lender of last resort (LOLR) rule originally implied by Articles 123 and 125 of the Treaty on the Functioning of the European Union (TFEU) towards a rule-with-exceptions and, increasingly, towards a presumption: The ECB will act as sovereign LOLR to a constituent Member unless and until that Member is insolvent or unwilling to cooperate with measures designed to restore market confidence. This functional moderation of a rule, from an ex ante specification of an outcome towards the exercise of greater choice at the point of application, carries with it contentious normative questions. To motivate discussion thereof beyond a largely ahistorical, non-indexical, rules versus discretion debate, the rules of the currency union are located within the genealogy of international exchange rate regimes. The “convertibility” rule of the gold standard and the “parity” rule of the Bretton Woods system are contrasted with their Eurozone equivalent. A consequentialist standpoint is sketched out from which the interventions of the ECB, in light of their available alternatives, appear broadly consistent with welfarist cost-benefit analysis and less normatively worrisome than by reference to evaluative criteria that emphasize a narrowly rule-bound conception of the rule of law.
The ground station market
Authors: Rabin S. J.
Published: March 2023

The foresight of Arthur C. Clark in suggesting that television pictures by way of a satellite could be sent direct to the viewer's home is about to come true. Whilst the professional communications fraternity have been using satellites for years for point to point communications it is only with the coming of high power satellites will viewers be able to receive pictures without the intervention of a terrestrial common carrier.
A European view of DBS
Authors: Rosetti C. , Chaplin J.
Published: March 2023

The first geostationary satellites were subject to a number of constraints stemming both from the relatively modest performance of the technique available at the time and from the payload capacity of the launchers used. Such constraints were either technological, eg, the modest power levels of the onboard transmitters or the highest usable frequency, or else economic, particularly the cost of placing a kilogram of satellite in geostationary orbit. At the time, these factors entailed the use of high-performance costly ground stations, which could be operated economically only for long-distance (intercontinental) communications between major traffic centres.
Aerospace reconnaissance and its exploitation
Authors: Oxlee G.J.
Published: March 2023

May I say that I consider it a great privilege to be asked to give this lecture to honour the memory of such a distinguished leader in the Aviation Industry.

Of the principles of war defined by Clausewitz the element of surprise has probably made the greatest contribution to success. In the military context therefore denial of surprise to a potential aggressor is paramount. Equally, the acquisition of intelligence to ensure surprise is a vital factor in any operational venture. As General Lemnitzer said in 1963, when Supreme Allied Commander Europe, ‘Aerial reconnaissance permits the effective use of valuable resources and forces and can easily spell the difference between the success and failure of any military operation’. These words underline the importance of reconnaissance to the successful conduct of war. This has been true throughout the history of warfare and perhaps never more so than during the Arab/Israeli wars of 1967 and 1973.
Development of methods for calibration and testing gyroscopic instruments for GW applications
Authors: Vaughan T.G. , Ward C.F.J.
Published: March 2023

As a preview to the main discussion, the role of the Twin Gyro Unit as a component part of the weapon's guidance system is first described. The reader will appreciate that there are as many types and configurations of gyro units as there are weapons and a full treatment of the subject would be beyond the scope of this paper. For the purposes of the discussion that follows, the gyro unit chosen is the two degree of freedom, electrically driven, Rotoraced displacement gyro, as used on the Sea Eagle, Anti Ship sea skimming missile.
Application of internal singularity distribution approach to multi-element aerofoil problems
Authors: Bandyopadhyay G. , Singh B. K. , Basu B. C.
Published: March 2023

A number of panel methods are now currently in use for solving potential flow about single and multi-element aerofoils. All these methods use a combination of singularities, both source and vorticity, on or inside the aerofoil surface and solve the singularity strengths by satisfying the boundary condition of zero normal flow on the surface of the aerofoil.

In this note the method developed by Basu for solving single aerofoil problem using the concept of internal singularity distribution has been applied to the case of multi-element aerofoil problem.
Oblique shock wave—turbulent boundary layer interaction with suction
Authors: Lee D. B. , Leblanc R.
Published: March 2023

The interaction of an incident oblique shock wave with the turbulent boundary layer with suction is investigated. Wall streamline and schlieren photograph visualisations as well as the pressure measurements on the wall are made. Boundary layer surveys with pressure probes and hot-wire probes are also done. The suction downstream of the interaction almost nullifies the shock reflection while the higher suction up and downstream of the interaction results in a reflection similar to that in inviscid flow.
Flight management systems and data links
Authors: Hendrickson Terrill W.
Published: March 2023

The latest generation of commercial jet transports, typified by the Boeing 757 and 767, is improved over prior generations by the widespread application of new technologies. For example, weight is being reduced by selective use of composite materials, by utilisation of stronger alloys in the structure, and by employment of computer-aided design and manufacturing techniques. Aerodynamic advances in wing design are reducing drag, lowering fuel burn, and allowing higher cruise altitudes. A new generation of engines are providing significant improvements in fuel consumption and noise suppression. But perhaps the most significant of the new technologies, is the extensive utilisation of digital computation in this latest generation of commercial transports.
Forecasting in air transport — a critical review of the techniques available
Authors: Hofton A. N.
Published: March 2023

An understanding of the market and the way it is likely to change with time is central to the planning of any business enterprise. Forecasting in air transport is particularly difficult because of the number of factors which influence the potential market (political, economic, social, environmental and technological) and because demand itself is very much influenced by the range of prices and qualities offered to the consumer. The lecture will review the purpose of forecasting and then examine the techniques of forecasting that are available in order to assess their usefulness in airline planning.

The preparation of a forecast is not an end in itself: rather it should be an essential and central element of the business activity. It should be part of the systematic search for opportunities and an aid to giving an overall direction to a business enterprise. For these reasons, forecasting should be seen as part of the mainstream of the planning activity and should not be left to isolated individuals in ‘backwater’ departments. Part of its value is in the formal evaluation of market intelligence and the understanding of the forces which are at work in the market place. Much of the benefit of a forecasting exercise will be lost if the ‘intelligence’ it generates is not diffused into the rest of the organisation. Similarly, line departments need to be involved in the forecasting process to help forecasters avoid ‘wishful thinking’ and pure ‘star gazing'.
Choice of optimal cabin capacity
Authors: Yeomans D. G.
Published: March 2023

Cabin capacity is the number of seats available. If there are too few seats too many potential passengers are turned away, potential revenue is not realised and the proper service is not provided to the travelling public. If there are too many seats a lot of them will be unused when demand is low and costs will be high in relationship to revenue.

Cabin capacity is a consideration when aircraft are being procured but at that stage it need not be calculated very precisely. Once the aircraft is in service quite small adjustments may make the difference between profit and loss, a particular problem being where to divide the cabin between the different classes.
The stiffness of transport wings for minimum weight
Authors: Hitch H.
Published: March 2023

The purpose of this note is to bring to attention a result which seems to have been long forgotten — indeed it may never have been widely known — and to present a parallel new result.

The ‘long forgotten’ result is that, for a simple cantilever thin walled torsion tube of area A(y) the torsional deflection θ at the tip when subjected to a torque T(y) is a minimum, for constant tube weight, if the skin thickness t(y) is proportional to , where y is the spanwise co-ordinate.
Do aeroplanes drive businessmen mad?
Authors: Prothero Thomas J.
Published: March 2023

Air transport, although now one of the world’s largest industries and a fundamental part of the web of commerce and communication, is still almost an infant in years. Some of us in the audience today will have been alive when the industry can have been said to have started, and the majority of us can certainly remember it as a tiny microcosm of the current worldwide system. But it is difficult to think of an industry which is not also a ‘business’ and it is open to question whether air transportation has ever been a ‘business’ in the true sense of the word. Its tools of production have very largely been subsidised (as far as their research and development costs are concerned), if one believes the manufacturers, very few of their programmes have shown satisfactory commercial output and as far as exports are concerned, most Governments have subsidised these at well below commercial rates of interest. When one adds to this a prediliction by the airlines themselves to sell their final product at less than its (unrealistically low) costs, then I believe my mystification on the financial justification for the industry is understandable. What are the real costs?
Keynote address
Authors: Morrison M.
Published: March 2023

The Commercial Transport Aircraft Industry, in common with most other industries, is gradually but continually changing its form and methods of operation to match the changing social, economic and technological climates of the world. It must be the concern of those responsible for Airworthiness within the industry to ensure that the present high levels of Airworthiness achieved are maintained and improved despite the changing circumstances.
Regulatory authority viewpoint
Authors: Chaplin J.C.
Published: March 2023

Airworthiness cannot be achieved by regulation. Regulation can establish a framework within which all who are concerned with the design, construction and operation of aircraft can work, and can set boundaries of responsible behaviour. Within that framework airworthiness can only be achieved by the actions of constructors, operators and authorities, and it is the management of those actions which is the subject of today’s discussions.