bluuebunny/crossref_metadata_2025 huggingface dataset:
For everything there is a season: Analysing periodic mortality patterns with the cyclomortr package
Authors: Gurarie Eliezer , Thompson Peter R. , Kelly Allicia P. , Larter Nicholas C. , Fagan William F. , Joly Kyle
Published: September 2019

Many important demographic processes are seasonal, including survival. For many species, mortality risk is significantly higher at certain times of the year than at others, whether because resources are scarce, susceptibility to predators or disease is high, or both. Despite the importance of survival modelling in wildlife sciences, no tools are available to estimate the peak, duration and relative importance of these ‘seasons of mortality’.

We present cyclomort, an r package that estimates the timing, duration and intensity of any number of mortality seasons with reliable confidence intervals. The package includes a model selection approach to determine the number of mortality seasons and to test whether seasons of mortality vary across discrete grouping factors.

We illustrate the periodic hazard function model and workflow of cyclomort with simulated data. We then estimate mortality seasons of two caribou Rangifer tarandus populations that have strikingly different mortality patterns, including different numbers and timing of mortality peaks, and a marked change in one population over time.

The cyclomort package was developed to estimate mortality seasons for wildlife, but the package can model any time‐to‐event processes with a periodic component.
Is fear of childbirth related to the woman’s preferred location for giving birth? A Dutch low‐risk cohort study
Authors: Sluijs Anne‐Marie , Cleiren Marc P.H.D. , van Lith Jan M.M. , Wijma Barbro , Wijma Klaas
Published: September 2019

Background

In The Netherlands, women with low‐risk pregnancy are routinely given the option of home birth, providing a unique opportunity to study the relationship between fear of childbirth (FOC) and preference for childbirth location, and whether women experience higher FOC when the actual location differs from their preference.

Methods

In this prospective cohort study, 331 nulliparous and parous women completed a questionnaire at gestational week 30 (T1) and two months postpartum (T2). FOC was assessed using versions A (T1) and B (T2) of the Wijma Delivery Expectancy/Experience Questionnaire (W‐DEQ).

Results

At T1, women who preferred home birth had significantly lower FOC compared with women who preferred a hospital birth (mean ± SD W‐DEQ scores: 55 ± 19.8 and 64 ± 18.3, respectively, P < .01). About 28% of women who responded at T2 gave birth at home. Congruence between the preferred and actual childbirth location was not predictive of FOC assessed at T2 when adjusted for obstetric and psychological variables. In an extended analysis, we found that except for prepartum FOC, the following variables also correlated with postpartum FOC: being referred because of complications and poor neonatal condition.

Conclusions

Compared to women who prefer hospital birth, women who prefer home birth have lower prepartum and postpartum FOC. Giving birth at a location other than the preferred location does not appear to affect postpartum FOC. Whether giving birth at home or in the hospital, caregivers should pay extra attention to women with high FOC because they are vulnerable to postpartum FOC, especially after a complicated birth and referral.
La ontología tras bastidores. Un problema metafísico para el naturalismo genético
Authors: Pérez Jiménez Miguel Ángel
Published: September 2019

Este trabajo es una crítica de ciertas concepciones de lo que llamamos una perspectiva genética de la naturalización: la tarea de investigar cómo la razón emerge del mundo natural. Para desarrollar nuestra crítica tomamos como marco de referencia dos importantes propuestas de Donald Davidson: el monismo anómalo y la analogía de la triangulación. Nuestro problema es el carácter metafísico del monismo y sus implicaciones para la empresa genética de naturalización de la razón. Defendemos que la concepción metafísica de la naturaleza del monismo anómalo, subyacente en la analogía de la triangulación, impide que la pregunta genética pueda plantearse de un modo inteligible y que, en esa medida, pueda aspirar a una respuesta razonable.
Foreign Object Impact Damage in Ceramic Matrix Composites: Experiments and Computational Predictions
Authors: Kumar Rajesh S. , Mordasky Matthew D.
Published: September 2019

Foreign object impact of ceramic matrix composite (CMC) materials and components in a gas turbine engine environment could be detrimental to engine performance and hence must be accounted for in the design of such components. This paper is concerned with experiments and computational modeling of foreign object impact phenomenon in silicon carbide (SiC)-based CMC. Controlled impact experiments were conducted on the CMC material using a gas-gun apparatus with spherical hardened steel projectile. The internal damage state within the CMC specimens was assessed using X-ray computed tomography scan technique. The computational modeling involved explicit dynamic finite element (FE) simulation of the impact process wherein either delamination mechanism is modeled or both ply damage and delamination mechanisms are modeled in a coupled manner. The delamination mechanism is modeled explicitly using cohesive-zone (CZ) fracture mechanics approach, whereas, the ply-damage mechanisms are modeled implicitly using simplified continuum damage mechanics approach. The simulation results were found to be in reasonable qualitative and quantitative agreement with the experimental results. Furthermore, it is shown that modeling both the ply damage and delamination mechanisms are essential to predict the correct delamination pattern even for intermediate velocity impacts that leads to predominantly delamination damage. The predictive nature of the modeling approach is demonstrated and approaches to enhance the models are also discussed.
Associations between occupational relative aerobic workload and resting blood pressure among different age groups: a cross-sectional analysis in the DPhacto study
Authors: Korshøj Mette , Clays Els , Krause Niklas , Gupta Nidhi , Jørgensen Marie Birk , Holtermann Andreas
Published: September 2019

Objective

High levels of occupational physical activity (OPA) increase heart rate, blood pressure (BP) and the risk of hypertension. Older workers may be more vulnerable to high levels of OPA due to age-related degeneration of the cardiovascular system and cardiorespiratory fitness. This study investigates the association of relative aerobic workload (RAW) with resting BP and examines if this relation is moderated by age.

Design

Cross-sectional epidemiological study.

Setting

Data were collected among employees of 15 Danish companies in the cleaning, manufacturing and transport sectors.

Participants

2107 employees were invited for participation, of these 1087 accepted and 562 (42% female and 4% non-Westerns) were included in the analysis based on the criteria of being non-pregnant, no allergy to bandages, sufficient amount of heart rate data corresponding to ≥4 work hours per workday or 75% of average work hours, and no missing outcome and confounder values.

Primary and secondary outcome measures

The primary outcome measure was BP.

Results

Heart rate reserve was estimated from ambulatory 24-hour heart rate measures covering 2.5 workdays per participant (SD 1.0 day). Age significantly moderated the association between RAW and BP. Mean intensity and duration of high RAW (≥30% heart rate reserve) showed positive associations with diastolic BP and negative associations with pulse pressure (PP) among participants ≥47 years old. Tendencies towards negative associations between RAW and BP were seen among participants <47 years old.

Conclusions

Mean intensity and duration of RAW increased diastolic BP among participants ≥47 years old. Negative associations with PP may be due to healthy worker selection bias. Prevention of hypertension should consider reductions in RAW for ageing workers.
Assessing non-conveyed patients in the ambulance service: a phenomenological interview study with Swedish ambulance clinicians
Authors: Lederman Jakob , Löfvenmark Caroline , Djärv Therese , Lindström Veronica , Elmqvist Carina
Published: September 2019

Objectives

To combat overcrowding in emergency departments, ambulance clinicians (ACs) are being encouraged to make on-site assessments regarding patients’ need for conveyance to hospital, and this is creating new and challenging demands for ACs. This study aimed to describe ACs’ experiences of assessing non-conveyed patients.

Design

A phenomenological interview study based on a reflective lifeworld research approach.

Setting

The target area for the study was Stockholm, Sweden, which has a population of approximately 2.3 million inhabitants. In this area, 73 ambulances perform approximately just over 200 000 ambulance assignments annually, and approximately 25 000 patients are non-conveyed each year.

Informants

11 ACs.

Methods

In-depth open-ended interviews.

Results

ACs experience uncertainty regarding the accuracy of their assessments of non-conveyed patients. In particular, they fear conducting erroneous assessments that could harm patients. Avoiding hasty decisions is important for conducting safe patient assessments. Several challenging paradoxes were identified that complicate the non-conveyance situation, namely; responsibility, education and feedback paradoxes. The core of the responsibility paradox is that the increased responsibility associated with non-conveyance assessments is not accompanied with appropriate organisational support. Thus, frustration is experienced. The education paradox involves limited and inadequate non-conveyance education. This, in combination with limited support from non-conveyance guidelines, causes the clinical reality to be perceived as challenging and problematic. Finally, the feedback paradox relates to the obstruction of professional development as a result of an absence of learning possibilities after assessments. Additionally, ACs also described loneliness during non-conveyance situations.

Conclusions

This study suggests that, for ACs, performing non-conveyance assessments means experiencing a paradoxical professional existence. Despite these aggravating paradoxes, however, complex non-conveyance assessments continue to be performed and accompanied with limited organisational support. To create more favourable circumstances and, hopefully, safer assessments, further studies that focus on these paradoxes and non-conveyance are needed.
Practice patterns among early-career primary care (ECPC) physicians and workforce planning implications: protocol for a mixed methods study
Authors: Lavergne M Ruth , Goldsmith Laurie J , Grudniewicz Agnes , Rudoler David , Marshall Emily Gard , Ahuja Megan , Blackie Doug , Burge Fred , Gibson Richard J , Glazier Richard H , Hawrylyshyn Steve , Hedden Lindsay , Hernandez-Lee Jacalynne , Horrey Kathleen , Joyce Mike , Kiran Tara , MacKenzie Adrian , Mathews Maria , McCracken Rita , McGrail Kimberlyn , McKay Madeleine , McPherson Charmaine , Mitra Goldis , Sampalli Tara , Scott Ian , Snadden David , Murphy Gail Tomblin , Wong Sabrina T
Published: September 2019

Introduction

Canadians report persistent problems accessing primary care despite an increasing per-capita supply of primary care physicians (PCPs). There is speculation that PCPs, especially those early in their careers, may now be working less and/or choosing to practice in focused clinical areas rather than comprehensive family medicine, but little evidence to support or refute this. The goal of this study is to inform primary care planning by: (1) identifying values and preferences shaping the practice intentions and choices of family medicine residents and early career PCPs, (2) comparing practice patterns of early-career and established PCPs to determine if changes over time reflect cohort effects (attributes unique to the most recent cohort of PCPs) or period effects (changes over time across all PCPs) and (3) integrating findings to understand the dynamics among practice intentions, practice choices and practice patterns and to identify policy implications.

Methods and analysis

We plan a mixed-methods study in the Canadian provinces of British Columbia, Ontario and Nova Scotia. We will conduct semi-structured in-depth interviews with family medicine residents and early-career PCPs and analyse survey data collected by the College of Family Physicians of Canada. We will also analyse linked administrative health data within each province. Mixed methods integration both within the study and as an end-of-study step will inform how practice intentions, choices and patterns are interrelated and inform policy recommendations.

Ethics and dissemination

This study was approved by the Simon Fraser University Research Ethics Board with harmonised approval from partner institutions. This study will produce a framework to understand practice choices, new measures for comparing practice patterns across jurisdictions and information necessary for planners to ensure adequate provider supply and patient access to primary care.
Body mass index variation over time and associated factors among HIV-positive adults on second-line ART in north-west Ethiopia: a retrospective follow-up study
Authors: Baraki Adhanom Gebreegziabher , Gezie Lemma Derseh , Zeleke Ejigu Gebeye , Awoke Tadesse , Tsegaye Adino Tesfahun
Published: September 2019

Objectives

This study aimed to assess the evolution of body mass index (BMI) of HIV-positive adults on second-line antiretroviral therapy (ART) over time and factors affecting it in north-west Ethiopia.

Design

An institution-based retrospective follow-up study was conducted using data extracted from 1016 patient cards from February 2008 to February 2016.

Setting

Eight referral hospitals from Amhara region, Ethiopia were included.

Participants

HIV patients who started second-line ART.

Outcome measures

Change in BMI since starting second-line ART.

Results

Five hundred and thirty-eight (52.95%) participants were males and the median age of the participants was 33 years (IQR: 28; 39). The median follow-up time was 18 months (IQR: 5.2; 32.2). The average change of BMI showed linear increase over time. The amount of BMI increment or decrement according to each variable was shown as β coefficients. Treatment duration (β=0.013, 95% CI 0.004 to 0.022), isoniazid prophylaxis (β=0.87, 95% CI 0.32 to 1.42), cotrimoxazole prophylaxis (β=0.63, 95% CI 0.08 to 1.19), ambulatory functional status (β=−1.16, 95% CI −1.95 to 1.31), bedridden functional status (β=−1.83, 95% CI −2.47 to 1.21), WHO stage III (β=−0.42, 95% CI −0.65 to 0.20), WHO stage IV (β=−0.62, 95% CI −1.02 to 0.22), CD4 count (β=0.001, 95% CI 0.0008 to 0.0015), and time interaction of variables like tertiary educational status (β=0.02, 95% CI 0.01 to 0.04), ambulatory functional status (β=0.03, 95% CI 0.01 to 0.05) and WHO stages III (β=0.01, 95% CI 0.007 to 0.02) were found to be significant predictors.

Conclusion

The BMI of patients has shown linear increment over the treatment time. Factors affecting it have been identified but its effect on cardiovascular disease needs further study.
Enhanced Corrosion Resistance of Recycled Aluminum Alloy 6061 Chips Using Hot Extrusion Followed by ECAP
Authors: Taha Mohamed A. , Abbas Adel T. , Benyahia Faycal , Alharbi Hamad F. , Guitián B. , Nóvoa X. Ramón
Published: September 2019

The oxidation of aluminum machining chips retards the successful recycling through the conventional remelting route. A promising approach to overthrow this problem is the utilization of solid state recycling in converting aluminum machining chips directly into semifinished products to eliminate the cost of the remelting process and reduce CO2 emissions. Therefore, in recent work, chips of aluminum alloy (AA6061) were recycled by compaction and then extrusion conducted at 500°C, followed by equal channel pressing (ECAP) to study the resultant material properties and its microstructure. Moreover, the present investigation explores the influence of ECAP after hot extrusion on the corrosive behaviour of the recycled samples in saline solution (NaCl) by electrochemical impedance spectroscopy (EIS) and linear polarization (LP). The results demonstrated a remarkable enhancement of the recycled chips’ properties subjected to hot extrusion followed by the ECAP process. Furthermore, the successive ECAP passes leads to increased film thickness and decreased corrosion rate.
Ternstroemia acajetensis (Pentaphylacaceae), a new species from the cloud forest in central Veracruz, Mexico

Authors: CASTILLO-CAMPOS GONZALO , PALACIOS-WASSENAAR OLIVIA M.
Published: September 2019

Ternstroemia acajetensis Cast.-Campos & Palacios-Wassenaar sp. nov. is described and illustrated. This new taxon is part of the arboreal and shrub strata of cloud forests, Quercus forests, and Pinus-Quercus forests in the mountains of the states of Veracruz, Puebla, and Oaxaca, Mexico. This species is related to T. sylvatica and T. huasteca, which grow in similar environments. However, the new species can be differentiated from the others by the length of the peduncle, the shape of the petals, the color of the flowers, and the length of the prolongation of the connective in the anthers.
Energy Fluxes in Coastal Trapped Waves
Authors: Musgrave R. C.
Published: September 2019

The calculation of energy flux in coastal trapped wave modes is reviewed in the context of tidal energy pathways near the coast. The significant barotropic pressures and currents associated with coastal trapped wave modes mean that large errors in estimating the wave flux are incurred if only the baroclinic component is considered. A specific example is given showing that baroclinic flux constitutes only 10% of the flux in a mode-1 wave for a reasonable choice of stratification and bathymetry. The interpretation of baroclinic energy flux and barotropic-to-baroclinic conversion at the coast is discussed: in contrast to the open ocean, estimates of baroclinic energy flux do not represent a wave energy flux; neither does conversion represent the scattering of energy from the tidal Kelvin wave to higher modes.
A calibration method of dual two-dimensional laser range finders for mobile manipulator
Authors: Song Tao , Wei Bang-Guo , Guo Shuai , Peng Jiang-Tao , Han Dong-Xiao
Published: September 2019

In this article, a method for calibrating the relative position between dual two-dimensional laser range finders is proposed. This relative position is affected by the manufacture or assembling error of mobile platform, and this error could reduce the accuracy of localization. This article focuses on three-degree-of-freedom calibration, that is, one rotational and two translational degrees of freedom. The entire calibration process can be summed up into three steps. The first step is to allow the dual finders to scan one corner at the same time and then extract the parameters of the corner. The second step is to establish a cost function which is established according to the direction vector of the line and the repeatability of the corners. With this function, the genetic algorithm is used to obtain the final calibration result. Moreover, the finder systematic error and the statistical error are also considered into this article. Simulations and experiments are carried out to verify the proposed method.
Determination of the DNA repair pathways utilised by acute lymphoblastic leukaemia cells following daunorubicin treatment
Authors: Al-Aamri Hussain Mubarak , Irving Helen R. , Meehan-Andrews Terri , Bradley Christopher
Published: September 2019

Objective

DNA double strand breaks (DNA-DSBs) are among the most lethal DNA lesions leading to genomic instability and repaired by either homologous recombination (HR) or the non-homologous end joining (NHEJ) mechanisms. The purpose of this study was to assess the importance and the level of activation of non-homologous end joining (NHEJ) and homologous recombination (HR) DNA repair pathways in three cell lines, CCRF-CEM and MOLT-4 derived from T lymphocytes and SUP-B15 derived from B lymphocytes following treatment with chemotherapy agent daunorubicin.

Results

The Gamma histone H2AX (γH2AX) assay was used assess the effects of DNA-PK inhibitor NU7026 and RAD51 inhibitor RI-2 on repair of DNA-DSB following treatment with daunorubicin. In all cell lines, the NHEJ DNA repair pathway appeared more rapid and efficient. MOLT-4 and CCFR-CEM cells utilised both NHEJ and HR pathways for DNA-DSB repair. Whereas, SUP-B15 cells utilised only NHEJ for DSB repair, suggestive of a deficiency in HR repair pathways.
Is chronic urticaria more than skin deep?
Authors: Kocatürk Emek , Grattan Clive
Published: September 2019

Chronic urticaria is a disease characterized by the appearance of weals, angioedema or both longer than 6 weeks. Degranulation of cutaneous or submucosal mast cells leads to release of mediators including histamine resulting in redness, swelling and itch. Because mast cells are widely distributed throughout the body, the question is why they are not activated systemically or does systemic activation occur without overt end organ dysfunction? We have conducted an exploratory literature search for reports that have evidence of organ-specific dysfunction in chronic urticaria that might justify prospective observational studies. This search revealed some evidence of systemic effects of chronic urticaria in cardiac, respiratory, gastrointestinal, central nervous and musculo-skeletal systems. The relevance of these findings needs to be further determined. However, they justify prospective studies in larger numbers of patients and at different stages of disease activity.
Ion milling: the perfect cross-section of a painted textile
Authors: Smith M. J. , Schmidt T. , Thompson K. , Dixon M.
Published: September 2019

The successful study and conservation of historical objects is greatly enhanced by accurate materials analysis. Here embedded cross-sections from a processional marching banner were viewed by scanning electron microscopy (SEM) pre and post ion milling The application of ion-milling to the resin embedded cross-sections of the painted textile improved the sample surface resulting in greatly enhanced SEM images by producing clear distinctions between layers. It also enabled clear images which show the areas where ingress of the ground paint layer had seeped into the textile support in some areas and not on others. This perhaps indicates deliberate differences in the preparation layer depending on the type of final painting layer or it could simply be due to a lack of accuracy in its application prior to painting. The analysis of cross-section samples from painted textiles often includes the textile itself making sample preparation more complex due to the possibility of fraying of the textile during sample polishing; the ion-milling technique prevented this from occurring. To enhance findings further analysis on these ion milled cross-section samples by the use of mapping spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR) and Raman would facilitate material identification of the layers.
Diversity and Molecular Characterization of Mosquitoes (Diptera: Culicidae) in Selected Ecological Regions in Kenya.
Authors: Makanda Moni , Kemunto Gladys , Wamuyu Lucy , Bargul Joel , Muema Jackson , Mutunga James
Published: September 2019

Mosquitoes play a predominant role as leading agents in the spread of vector-borne diseases and the consequent mortality in humans. Despite reports on increase of new and recurrent mosquito borne-disease outbreaks such as chikungunya, dengue fever and Rift Valley fever in Kenya, little is known about the genetic characteristics and diversity of the vector species that have been incriminated in transmission of disease pathogens. In this study,  mosquito species were collected from Kisumu city, Kilifi town and Nairobi city and we determined their genetic diversity and phylogenetic relationships. PCR was used to amplify the partial cytochrome oxidase subunit 1 (CO1) gene of mosquito samples. Molecular-genetic and phylogenetic analysis of the partial cytochrome oxidase subunit 1 (CO1) gene were employed to identify their relationship with known mosquito species. Fourteen (14) haplotypes belonging to genusAedes, nine (9) haplotypes belonging to genusAnophelesand twelve (12) haplotypes belonging to genusCulexwere identified in this study. Findings from this study revealed a potentially new haplotype belonging toAnophelesgenus and reported the first molecular characterization ofAedes cumminsiiin Kenya. Sequence results revealed variation in mosquito species from Kilifi, Kisumu and Nairobi. Since vector competence varies greatly across species as well as species-complexes and is strongly associated with specific behavioural adaptations, proper species identification is important for vector control programs.
Recommendations and Alerting for Delirium Alleviation in Real-Time (RADAR): Protocol for a pilot randomized controlled trial
Authors: Vlisides Phillip E. , Ragheb Jacqueline W. , Leis Aleda , Schoettinger Amanda , Hickey Kim , McKinney Amy , Brooks Joseph , Zierau Mackenzie , Norcott Alexandra , Yang Shirley , Avidan Michael S. , Min Lillian
Published: September 2019

Background: Delirium is a common and serious complication of major surgery for older adults. Postoperative social and behavioral support (e.g., early mobilization, mealtime assistance) may reduce the incidence and impact of delirium, and these efforts are possible with proactive patient-care programs. This pilot trial tests the hypothesis that a multicomponent decision support system, which sends automated alerts and recommendations to patient-care programs and family members for high-risk patients, will improve the postoperative environment for neurocognitive and clinical recovery.

Methods: This will be a randomized, controlled, factorial pilot trial at a large academic medical center. High-risk, non-cardiac surgery patients (≥70 years old) will be recruited. Patients will be allocated to a usual care group (n=15), Hospital Elder Life Program (HELP)-based paging system (n=15), family-based paging system (n=15), or combined HELP- and family-based system (n=15). The primary outcome will be the presence of delirium, defined by positive long-form Confusion Assessment Method screening. Secondary outcomes will include additional HELP- and family-based performance metrics along with various neurocognitive and clinical recovery measures. Exploratory outcomes include the incidence of positive family-based delirium assessments post-discharge, 36-item Short Form Survey, PROMIS Cognitive Function Abilities Subset 4a, and 30-day readmission rates.

Ethics and dissemination: This trial has received approval by the University of Michigan Medical Institutional Review Board (IRBMED). Dissemination plans include presentation at scientific conferences, publication in medical journals, and distribution via educational and news media.

Registration: ClinicalTrials.gov Identifier NCT04007523, registered on 7/3/2019.
Analysis of methods of self-study in the discipline "Weapon raining" in educational institutions of the Ministry of internal Affairs of Russia
Authors: Мышенкова Юлия , Mishenkova Julia
Published: September 2019

The object of the study in this article is the independent work of students in educational institutions of the Ministry of internal Affairs of Russia by studing the discipline " Weapon training". The subject of the study is the methodological recommendations of independent studies of educational establishments of the Ministry of internal Affairs of Russia on the discipline " Weapon training". Particular attention is paid to the analysis of available guidelines for independent work of students in fire training. The author identified a number of problems, as well as the need to eliminate them and further improve the methods of self-study. In addition, the article presents the initial data of the survey of teachers and cadets of educational organizations of the Ministry of internal Affairs of Russia, which reflect the state of organizational and methodological conditions of independent work on the discipline " Weapon training" at the moment. The main methods used in this article are bibliographic search, analysis of available guidelines, their comparison, as well as questioning of teachers and cadets of educational organizations of the Ministry of internal Affairs of Russia. The novelty of this study is that in connection with the transition to the pedagogical paradigm of developing training, it is necessary to develop independence in the development of the discipline " Weapon training". The main conclusion of the study is the need to develop guidelines for independent work of cadets in Weapon training, which will facilitate the assimilation of the material discipline cadets of educational establishments of the Ministry of internal Affairs of Russia.
On Democritean Rhysmos
Authors: Gomes Gustavo Laet
Published: September 2019

In Metaphysics A.4 (985b4-19 [DK67 A6]), Aristotle provides crucial information about fundamental aspects of the chemistry and microphysics of the atomic theory of Leucippus and Democritus of Abdera. Besides the plenum and the void, which he identifies as the elements of the atomic theory, he presents what he himself names as differences. These fundamental differences are named so because they ought to be responsible for the emergence of all other differences in the physical world, and especially the ones that hit our senses. Aristotle provides a list of three differences both in what is recognized as autochthonous terminology from Leucippus and Democritus, and in a translation to terms apparently more intelligible to Aristotelian listeners. Among those differences there is one in particular that is harder to comprehend than the other ones: rhysmos. Aristotle’s translation of rhysmos into schēma has led most interpreters to acknowledge that it referred solely to atoms individually, while the other two differences would refer to relations between atoms. In this paper, I want to propose an interpretation in which rhysmos actually refers to several aspects of the chemistry and microphysics of the atomic theory.
Beitrag zum Material über den Einfluß des magnetischen Sturmes vom l.März 1941 auf die Ultrastrahlung
Authors: Sittkus Albert
Published: September 2019

Von Kolhö rster veröffentlichtes Material über den Einfluß des magnetischen Sturmes vom 1. März 1941 auf die Ultrastrahlung, wie er sich in den Zählrolirkoinzidenzmessungen in Dahlem und Graz ausprägt, wird durch Ionisationskammermessungen in Freiburg i. Br. ergänzt, und eine Abschätzung des Temperatureinflusses bei den 3 Stationen durchgeführt. Es ergibt sich eine qualitativ gleichartige Einwirkung der magnetischen Störung auf den Verlauf der Ultrastrahlung über einen Bereich von etwa 6 Breiten- und 8 Längengraden, während sich die Amplituden der Schwankung unterscheiden. Es zeigt sich dabei noch, daß eine Ausschaltung meteorologischer Einflüsse durch Vergleich räumlich weit getrennter Stationen im Bereich Deutschlands nicht immer gewährleistet ist.
Über blutgerinnungshemmende Substanzen
Authors: Husemann E. , Kaulla K. N. von , Kappesser R.
Published: September 2019

Abstrakt

Es wurden Schwefelsäureester polymerhomologer Reihen von Cellulosen, Polyvinylalkoholen, Stärken und Glykogenen hergestellt und auf ihre dem Heparin ähnliche blutgerinnungshemmende Wirksamkeit sowie ihre Toxizität untersucht, um den Einfluß von Molekülgestalt und Molekülgröße zu studieren. Es ergab sich, daß die unverzweigten Cellulosen und Polyvinylalkohole sehr wirksam sind, während die verzweigten Stärken und kugeligen Glykogene die Blutgerinnung wesentlich weniger, z. Tl. gar nicht hemmen. Bei den unverzweigten Produkten nimmt die Wirksamkeit mit steigendem Molekular-, gewicht in geringem Maße ab, die Toxizität ganz erheblich zu. Größte Wirksamkeit und geringste Toxizität fanden sich bei Fadenmolekülen mit Polymerisationsgraden zwischen etwa 20 und 80.

Im Xylanschwefelsäureester wurde eine sehr wirksame und nahezu untoxische Substanz gefunden, die bereits klinisch mit Erfolg bei akuter Thrombose verwandt werden konnte
Die Masse der kugelförmigen Sternhaufen M 3 und M 13
Authors: Lohmann Werner
Published: September 2019

Unter Annahme der in Sonnenumgebung herrschenden Leuchtkraftfunktion nach Kuiper berechnet sich die Masse von M3 bzw. M 13 zu 70000 bzw. 110000 Sonnen-massen.
Untersuchungen an Kurzwellen-Echosignalen II. Teil
Authors: Hess Hanns Albrecht
Published: September 2019

In der früheren Abhandlung 2 gleicher Überschrift sind Untersuchungen nur an Signalen bei mehr als 1000 km vom Beobachtungsort entfernten Kurzwellensendern des Frequenzbereiches 10 bis 20 MHz enthalten. In dieser Fortsetzung wird über Signaluntersuchungen an näher liegenden Kurzwellensendern berichtet. Es treten hier sehr ausgeprägte Mehrweg-Phänomene beim Hauptsignal in Erscheinung, durch die zu-meist ionosphärische Entfernungsbestimmungen undurchführbar sind. Durch Laufzeit-messungen zwischen den nacheinander eintreffenden Signalen unter Einbeziehung der von diesem Phänomen nicht betroffenen Erdumläufe in dieselben, ferner durch Antennenversuche und Betrachtungen über die ionosphärisch bedingte Echozone wird versucht, Aufschlüsse über diese Mehrweg-Phänomene zu finden.
Eine Erweiterung des Differenzen-Verfahrens zur Berechnung von kugelsymmetrischen Temperaturfeldern
Authors: Schwan Hermann
Published: September 2019

Mit dem Differenzenverfahren können in einfacher Weise beliebige Anheiz- und Abkühlungsvorgänge, soweit sie kugelsymmetrisch verlaufen, behandelt werden. Sowohl der Fall, daß eine Kugel von einem Medium konstanter Außentemperatur umgeben wird, wie auch der Fall, daß die Temperatur ohne Störung durch Konvektion in der Umgebung der geheizten Kugel sich einstellt, wird erörtert und führt auf leicht durchführbare Rechnungen und Konstruktionen. Zum Schluß wird gezeigt, wie sich aus den angegebenen Rekursionsformeln die analytischen Gesetzmäßigkeiten der stationären Temperaturverteilung leicht elementar ableiten lassen.
Kinetische Theorie der Thermoosmose (Thermodiffusion durch Membranen)
Authors: Wirtz Karl
Published: September 2019

Zwischen zwei Räumen verschiedener Temperatur, die mit demselben Gas bzw. derselben Flüssigkeit gefüllt und durch eine permeable Membran getrennt sind, stellt sich ein Druck-unterschied ein, der von der diffundierenden Substanz und von der Natur der Membran abhängt. Überlegungen über die Diffusionsschritte an der Membranoberfläche und in der Membran zeigen den Zusammenhang zwischen dieser "Thermoosmose" und der "Über-führungswärme", d. i. die Wärme, die das Teilchen bei seiner Wanderung durch die Membran aus dem einen in den anderen Raum überführt. Eastman hat aus thermo-dynamischen Überlegungen Gesetze gefolgert, die im folgenden durch Platzwechsel-betrachtungen für spezielle Fälle kinetisch abgeleitet werden. Es zeigt sich, daß nur die Überführungswärme beim Schritt durch die Membranoberfläche für die Thermoosmose verantwortlich ist, nicht die innerhalb der Membran. Die Überführungswärme stimmt in speziellen Fällen mit der Lösungswärme der Flüssigkeit in der Membran überein, wäre dann also im Prinzip mittels kalorischer Messungen ganz änderer Art bestimmbar.
Versuche mit Uran-und Thorzählrohren
Authors: Wiebe Werner
Published: September 2019

Ein Messingzählrohr wird mit Uranoxyd bzw. mit Thoriumblech ausgekleidet und im Proportionalbereich betrieben. Bei Bestrahlung mit einer Neutronenquelle können die Bruchstücke der Kernspaltung von den α-Teilchen unterschieden werden. Das Thor-zählrohr kann zur Zählung von schnellen Neutronen benutzt werden.
Ein wellenmechanisches Modell des Supraleiters
Authors: Welker Heinrich
Published: September 2019

Herrn Geheimrat Arnold Sommerfeld zum 80. Geburtstage gewidmet In Abschn. 2 werden für ein aus Elektronen und Defektelektronen bestehendes Elektronengas Wellenfunktionen aufgestellt, die zwar nicht die gesamte elektromagnetische Wechselwirkung des Elektronengases berücksichtigen, die jedoch möglicherweise die wesentlichen Züge der Wechselwirkung eines Aufelektrons mit der Gesamtheit aller übrigen Elektronen richtig beschreiben. Es zeigt sich, daß bei Berücksichtigung der Coulombschen Wechselwirkung in einem eng begrenzten Bereich der Elektronendichte eine Entartung übrigbleibt, die erst bei Berücksichtigung der magnetischen Wechselwirkung aufgehoben wird. Das niedrigere Energieniveau wird dem supraleitenden, das höhere dem normalleitenden Zustand des Aufelektrons zugeordnet. In Abschn. 3 wird die maximale Dichte der sich im supraleitenden Zustand befindlichen Aufelektronen und damit die gesamte Energiedichte des supraleitenden Zustands berechnet sowie das Zu-standekommen des vollständigen Diamagnetismus und der unendlichen Leitfähigkeit erörtert. In Abschn. 4 werden die aus der Theorie sich ergebenden Folgerungen über die Lage der Supraleiter im periodischen System und die Höhe der Sprungpunkte gezogen.
Die Innentemperaturen der überdichten Zwerge und das Auftreten von Bose-Entartung
Authors: Biermann Ludwig
Published: September 2019

Die Temperatur des Inneren der überdichten Sterne unterhalb der Hauptreihe im Farbenhelligkeitsdiagramm wird mit den Mitteln der Theorie des Sternaufbaus untersucht. Für die Sterne sehr geringer Leuchtkraft ( < 10-4 derjenigen der Sonne) finden sich Werte um 1 Million Grad. Im Verein mit der überaus hohen Dichte bewirkt dies Entartung (im Sinne der statistischen Mechanik) nicht nur der freien Elektronen, sondern auch der leichtesten Atomkerne.
Das Herzfeidsche Metallkriterium und die Frage nach der Existenz einer nichtleitenden, amorphen Modifikation aller Metalle
Authors: Mayer Herbert
Published: September 2019

Herzfeld hat aus der Dispersionstheorie als Bedingung dafür, daß beim Zusammen-treten von Atomen eines Elementes zu einem flüssigen oder festen Körper ein Metall entsteht, abgeleitet, daß das molekulare Breehungsvermögen größer sein muß als der Quotient Molekulargewicht/Dichte. Es wird gezeigt, daß diese Bedingung neuere Ergebnisse über die elektrische Leitfähigkeit dünner Metallschichten zu erklären vermag.
Vergleich von Schwärzungsdifferenz-und Linienbreitenverfahren für die quantitative spektrochemische Analyse
Authors: Rollwagen Walter , Weltz Hildegard
Published: September 2019

Es wird das übliche Verfahren der Schwärzungsmessung mit dem neuen Verfahren der Breitenmessung zur Bestimmung von Intensitätsverhältnissen von Spektrallinien verglichen. Dabei ergibt sich, daß das Breitenverfahren grundsätzlich von Vorteil ist, wenn eine der Linien starke Selbstumkehr zeigt, und daß in allen übrigen Fällen das Breitenverfahren nur dann Vorteile bringt, wenn die verwendete Analysenmethode keine exakte Berücksichtigung der Plattencharakteristik in sich schließt.
Verlustfreie optische Interferenz-Polarisatoren
Authors: Schröder Hubert , Schläfer Rudolf
Published: September 2019

Die Erzeugung von linearpolarisiertem Licht durch interferenzfähige dielektrische Schichten nach einer früher beschriebenen Methode läßt eine verlustlose Ausnützung der beiden, durch das Sehichtsystem getrennten, entgegengesetzt zueinander polarisierten Komponenten zu.
Ein graphisches Verfahren zur Berechnung von Strukturfaktoren für die Röntgenanalyse von Kristallen
Authors: Hoppe Walter , Camerer L.
Published: September 2019

Es wird ein graphischer Behelf zur Bestimmung der Strukturfaktoren von Kristall-Strukturen beschrieben, der vor allem bei nieder symmetrischen und atomreichen Gittern die schnelle und ausreichend genaue Berechnung aller Röntgenintensitäten eines Kristalles ermöglicht.
Die Reflexion einer Welle an einer Potentialschwelle
Authors: Koppe Heinz
Published: September 2019

Durch eine Abänderung der WBK-Methode wird ein Näherungsausdruck für den Reflexionskoeffizienten R gefunden, der für kleines R gültig ist
Über einen konzentrationsabhängigen H-D-Austauschprozeß an den Oberflächen von Aluminiumkathoden
Authors: Kühne-Sauter Eva
Published: September 2019

Es wird ein Deuterium-Anreicherungs-Prozeß untersucht, der an Aluminium-Oberflächen stattfindet, die im Vakuum mit D2O-H2O-Gemischen bestimmter Konzentration benetzt wer-den und als Kathoden einer Glimmentladung spektroskopischen Messungen zugänglich sind. Quantitative Spektraluntersuchungen ergeben eine Abhängigkeit der Anreicherung von der Konzentration der Ausgangsflüssigkeit. Es wird bei stärkerer D2O-Konzentration eine Anreicherung des D in der Kathode festgestellt, während bei Daq/Haq-Verhältnissen < 1:400 eine Verarmung an Deuterium beobachtet wird.
Elektronenmikroskopische Untersuchung der physikalischen Reifung von chlorsilberarmen photographischen Emulsionen
Authors: Ammann-Brass Hans
Published: September 2019

Während der physikalischen Reifung einer photographischen Halogensilbergelatine-Emulsion findet eine Teilchenvergrößerung statt, welche sich durch Zunahme der Trübung zu erkennen gibt. Der Verlauf der Reifung hängt u. a. von Gelatine-Charakter und -Konzentration ab.

Die auffallende Beschleunigung der Trübungszunahme, die in AgCl-Emulsionen mit hohem Gehalt an aktiver Gelatine beobachtet wird, hat dazu geführt, zwei Arten der physikalischen Reifung anzunehmen, nämlich

1. die reine Ostwald-Reifung, und

2. die Teilchenvergrößerung infolge von Koagulation.

Die sich tatsächlich bei der Reifung abspielenden Vorgänge wurden mit Hilfe des Elektronenmikroskopes untersucht. Die Ergebnisse haben die Annahme bestätigt.

Es konnte für den einfacheren Fall der Ostwald-Reifung eine lineare Beziehung zwischen Trübung und mittlerer Korngröße nachgewiesen werden.
27d -Variation der harten Komponente der kosmischen Strahlung und Magnetfeld der Erde zur Zeit eines Minimums der Sonnenaktivität
Authors: Gheri Herma
Published: September 2019

In erster Näherung kann die eckige Klammer gleich Eins gesetzt werden. Mit den hier entwickelten Näherungsmethoden können Wellenvorgänge in Motoren und Rohren mit maximalen Überdrucken von etwa 1,5 at ausreichend beschrieben werden, wie die Verfasser in den oben zitierten Arbeiten über das Schmidt-Rohr gezeigt haben. An einem 23 Sonnenrotationen umfassenden Beobachtungsmaterial der kosmischen Strahlung wird gezeigt, daß nur ein geringer Anteil der 27-Tage-Variation durch erdmagnetische Einflüsse gedeutet werden kann. Nach der magnetischen Korrektur der' Strahlungswerte zeigt die Häufigkeitsverteilung der Lage des Maximums im Gegensatz zur unkorrigierten Strahlung zwei den Störpegel deutlich überragende Spitzen: a) 12 Rotationen mit Maximum am 1.--6. Tag, b) 5 Rotationen mit Maximum am 9.-11. Tag. Während der Rotationen a), die hauptsächlich zur Zeit der magnetischen Wiederkehr beobachtet wurden, scheint die Emission der Wellenstrahlung der Sonne am Beginn des Rotationsintervalls verringert zu sein (erschlossen aus dem Verlauf der Bodentemperatur), so daß es plausibel erscheint, die Variation der Strahlung während dieser Rotationen durch atmosphärische Einflüsse zu erklären. Eine Deutung der Variationen b) war nicht möglich.
Continously Perturbed Equivalent Classes of Asymptotically Stable Kinetic Equations
Authors: Nazarea A. D.
Published: September 2019

Equivalent classes of kinetic (rate) equations for which each class is asymptotically stable with respect to a unique steady-state are assumed subject to a multi-dimensional stochastic Pertubation arising as the time derivative of a vector-valued normalized Wiener process. A general condition for stability of the steady-state, with probality one, under such continously acting random perturbations is derived in terms of the kinetic potential. An application of this condition is given in the appendix.
Superconducting Properties of Nb3Sn with High Carbon Doping
Authors: Ziegler G.
Published: September 2019

The superconducting compound Nb3Sn was heavily doped with carbon during chemical vapour deposition and then annealed. Very high current carrying capacities could be attained by this method (3.2 × 106 A/cm2 at 5 T).
Removal and Single Particle Energies in Nuclei
Authors: Faessler Amand , Müther H.
Published: September 2019

The difference between the absolute value of the Hartree-Fock (HF) single particle energy and the removal energy is studied. This total rearrangement is composed out of the orbital (or spatial) and the Brueckner rearrangement. It is shown analytically within the Pauli-Brueckner HF (PBHF) approach that the saturation potential 〈h | ∂V/∂ρ | h〉 for a density dependent effective force is equal to the Brueckner rearrangement energy of the level | h〉 plus a smaller term. This is in 16O accidentally numerically roughly equal to the orbital rearrangement energy. The numerical calculation in 16O of the rearrangement energies for the proton level yields the maximum value (9 MeV) for the Os½ state. The Brueckner rearrangement is from a factor two to twenty larger than the orbital rearrangement.
Gravitation und bilokale Feldtheorie / Gravitation and Bilocal Field Theory
Authors: Vollendorf F.
Published: September 2019

Gravitation and Bilocal Field Theory The starting point is the conjecture that a field theory of elementary particles can be constructed only in a bilocal version. Thus the 4-dimensional space time has to be replaced by the 8-dimensional manifold

of all ordered pairs of space time events. With special reference to the Schwarzschild metric it is shown that the embedding of the space time into the manifold

yields a description of the gravitational field.
Burgers Equation for Wave Propagation in an Infinite Stout-Wall Tube
Authors: Murawski K.
Published: September 2019

The reductive Taniuti-Wei method is used to obtain the Burgers equation for a wave propagating in an infinite stout-wall tube.
Vector Potential and Magnetic Field of Current-carrying Finite Elliptic Arc Segment in Analytical Form
Authors: Urankar L.
Published: September 2019

Analytical expressions for the components of the vector potential and magnetic field of a current-carrying elliptic arc filament of arbitrary length are derived. All the expressions developed consist of only known functions such as Jacobian elliptic functions, complete and incomplete elliptic integrals of the first, second and third kind, and thus permit a compact timesaving efficient computation algorithm.
Diffraction Pattern and Layer Structure of a Quasilattice
Authors: Kramer P. , Kramer L.
Published: September 2019

Structure calculations are reported for a quasilattice associated with the icosahedral group. The diffraction pattern is computed in a one-center and long-range approximation and compared to experiments on Al + 14% Mn. Edge and vertex positions of the quasilattice are computed in a projection onto a plane with a layer structure.
Total Cross Section of Sulphur at Slow Neutron Energies
Authors: Mayer R. E. , Gillette V. H. , Granada J. R.
Published: September 2019

The total cross section of elemental Sulphur was measured at neutron energies between 1.6 x 10-3 eV and 100 eV, using a pulsed neutron source and time-of-flight techniques.

The data in the epithermal neutron region were used to extract the value of the bound nucleus scattering length, taking into account the neutron-electron interaction. A similar transmission experiment was also performed on elemental Bismuth.
Notizen: The Viscosity of Aqueous BaCl2 + NaCl Solutions
Authors: Rakshit Animesh Kumar
Published: September 2019

Viscosities of the title solution were measured at 35, 40, 45 and 50 °C for 0.2, 0.3 and 0.4 M NaCl and 7BaCl2 concentrations. Considering the NaCl solutions as the solvents for BaCl2, the results were com pared with the Jones-Dole equation, the Moulik equation and the Vand equation.
The Pressure Dependence of T2- Relaxation Rates for Rotational Transitions of Sulfur Dioxide in Mixtures with Oxygen and Nitrogen
Authors: Wolf P. , Mäder H.
Published: September 2019

The transient emission technique in the time domain has been used to determine the pressure dependence of the coherent dephasing time T2 of sulfur dioxide in mixtures with O2 and N2 for several rotational transitions in the vibrational ground state. From these data line broadening parameters Δv/p and collisional cross-sections are calculated.