bluuebunny/crossref_metadata_2025 huggingface dataset:
The millennium problems. Challenges to further mathematics
Authors: Segura de León Sergio
Published: March 2024

Although it may seem surprising, the field of mathematics experiences constant advances. Each year, new results are published using original concepts and methods that have a relevant impact on the following years. We must note that some of these new results are obtained with the solution to previously raised issues. Some of these problems are studied for many years, so many, in fact, that they end up becoming notorious. For instance, we can highlight three well-known ruler-and-compass constructions from ancient times (doubling the cube, trisecting the angle and squaring the circle); we have only known they are unsolvable since the nineteenth century.
The scam of pseudoscience
Authors: Fasce Angelo
Published: March 2024

P Nombre y apellido seudosciences are by-products of the prestige of science as a social enterprise and as a means of obtaining knowledge. Their character is inherently negative, given that, by definition, a pseudoscience is an intellectual fraud consisting of products, practices, or ideas unconnected with scientific rationality that are asserted as science to society, in an act of rhetorical enhancement of their dubious goodness. For several decades they have attracted great interest, not only because of the strange and sometimes extreme nature of their contents, but also because of the alarming penetration they have reached in highly sensitive environments, such as the education or health system systems.
Phraseological microsystem "Deviant human behavior" in Russian, Ukrainian and Crimean Tatar languages
Authors: Grozyan Nina Fedorovna , Prudnikova Tatiana Ivanovna , Ibragimova Venera Fevzievna
Published: March 2024

The article is devoted to the ideographic and semantic characteristics of phraseological units. The subject of the study is the phraseological units of the Russian, Ukrainian and Crimean Tatar languages, denoting deviant human behavior.The purpose of the article is to identify from the phraseological composition of the Russian, Ukrainian and Crimean Tatar languages a group of phraseological units, the common semantic feature of which has an extralinguistic nature (all of them denote deviant human behavior), and to describe the semantic features of these phraseological units, taking into account the achievements of modern phraseological and psychological sciences. The scheme of ideographic classification of the language proposed by Professor Y. F. Pradid and tested in the works of his students was used in the work. The ideographic classification has the following structure: synonymic series → semantic group → semantic field → thematic group → thematic field → ideographic group → ideographic field → archipole. Two thematic groups are distinguished in the thematic field of phraseological units "Deviant human behavior": "Criminal human behavior", "Criminally non-punishable (non-contrary) immoral human behavior".   The theoretical and methodological basis of the research was the works of domestic and foreign scientists in the field of phraseology and psychology. A descriptive method was used when writing the article. The scientific novelty of the research is determined by a comprehensive approach to the analysis of the complex mechanism of the phraseological microsystem "Deviant human behavior" in Russian, Ukrainian and Crimean Tatar languages. The complex application of ideographic and semantic aspects allowed us to obtain new results regarding the essence and semantic organization of this layer of phraseological units, the place of the phraseological microsystem "Deviant human behavior" in the structure of the phraseological system of the Russian, Ukrainian and Crimean Tatar languages. The ideographic and semantic analysis of phraseological units combined into the phraseological microsystem "Deviant human behavior" gave grounds to conclude that the structure of this thematic field corresponds to the categorization of deviant behavior presented in psychological science. The analysis of phraseological units denoting deviant human behavior will contribute to further linguistic research of phraseological ideography, the development of a general typology of research methods for phraseological microsystems in ideographic and semantic aspects.
Automated cell annotation in multi-cell images using an improved CRF_ID algorithm
Authors: Lee Hyun Jee , Liang Jingting , Chaudhary Shivesh , Moon Sihoon , Yu Zikai , Wu Taihong , Liu He , Choi Myung-Kyu , Zhang Yun , Lu Hang
Published: March 2024

Cell identification is an important yet difficult process in data analysis of biological images. Previously, we developed an automated cell identification method called CRF_ID and demonstrated its high performance in
C. elegans
whole-brain images (Chaudhary et al, 2021). However, because the method was optimized for whole-brain imaging, comparable performance could not be guaranteed for application in commonly used
C. elegans
multi-cell images that display a subpopulation of cells. Here, we present an advance CRF_ID 2.0 that expands the generalizability of the method to multi-cell imaging beyond whole-brain imaging. To illustrate the application of the advance, we show the characterization of CRF_ID 2.0 in multi-cell imaging and cell-specific gene expression analysis in
C. elegans
. This work demonstrates that high accuracy automated cell annotation in multi-cell imaging can expedite cell identification and reduce its subjectivity in
C. elegans
and potentially other biological images of various origins.
Episodic long-term memory formation during slow-wave sleep
Authors: Schmidig Flavio J. , Ruch Simon , Henke Katharina
Published: March 2024

We are unresponsive during slow-wave sleep but continue monitoring external events for survival. Our brain wakens us when danger is imminent. If events are non-threatening, our brain might store them for later consideration to improve decision-making. To test this hypothesis, we examined whether novel vocabulary consisting of simultaneously played pseudowords and translation words are encoded/stored during sleep, and which neural-electrical events facilitate encoding/storage. An algorithm for brain-state dependent stimulation selectively targeted word pairs to slow-wave peaks or troughs. Retrieval tests were given 12 and 36 hours later. These tests required decisions regarding the semantic category of previously sleep-played pseudowords. The sleep-played vocabulary influenced awake decision-making 36 hours later, if targeted to troughs. The words’ linguistic processing raised neural complexity. The words’ semantic-associative encoding was supported by increased theta power during the ensuing peak. Fast-spindle power ramped up during a second peak likely aiding consolidation. Hence, new vocabulary played during slow-wave sleep was stored and influenced decision-making days later.
Determinantal Point Process Attention Over Grid Cell Code Supports Out of Distribution Generalization
Authors: Mondal Shanka Subhra , Frankland Steven , Webb Taylor W. , Cohen Jonathan D.
Published: March 2024

Deep neural networks have made tremendous gains in emulating human-like intelligence, and have been used increasingly as ways of understanding how the brain may solve the complex computational problems on which this relies. However, these still fall short of, and therefore fail to provide insight into how the brain supports strong forms of generalization of which humans are capable. One such case is out-of-distribution (OOD) generalization— successful performance on test examples that lie outside the distribution of the training set. Here, we identify properties of processing in the brain that may contribute to this ability. We describe a two-part algorithm that draws on specific features of neural computation to achieve OOD generalization, and provide a proof of concept by evaluating performance on two challenging cognitive tasks. First we draw on the fact that the mammalian brain represents metric spaces using grid cell code (e.g., in the entorhinal cortex): abstract representations of relational structure, organized in recurring motifs that cover the representational space. Second, we propose an attentional mechanism that operates over the grid cell code using Determinantal Point Process (DPP), that we call DPP attention (DPP-A) - a transformation that ensures maximum sparseness in the coverage of that space. We show that a loss function that combines standard task-optimized error with DPP-A can exploit the recurring motifs in the grid cell code, and can be integrated with common architectures to achieve strong OOD generalization performance on analogy and arithmetic tasks. This provides both an interpretation of how the grid cell code in the mammalian brain may contribute to generalization performance, and at the same time a potential means for improving such capabilities in artificial neural networks.
Machine learning of dissection photographs and surface scanning for quantitative 3D neuropathology
Authors: Gazula Harshvardhan , Tregidgo Henry F. J. , Billot Benjamin , Balbastre Yael , William-Ramirez Jonathan , Herisse Rogeny , Deden-Binder Lucas J , Casamitjana Adrià , Melief Erica J. , Latimer Caitlin S. , Kilgore Mitchell D. , Montine Mark , Robinson Eleanor , Blackburn Emily , Marshall Michael S. , Connors Theresa R. , Oakley Derek H. , Frosch Matthew P. , Young Sean I. , Van Leemput Koen , Dalca Adrian V. , FIschl Bruce , Mac Donald Christine L. , Keene C. Dirk , Hyman Bradley T. , Iglesias Juan Eugenio
Published: March 2024

We present open-source tools for 3D analysis of photographs of dissected slices of human brains, which are routinely acquired in brain banks but seldom used for quantitative analysis. Our tools can:
(i)
3D reconstruct a volume from the photographs and, optionally, a surface scan; and
(ii)
produce a high-resolution 3D segmentation into 11 brain regions per hemisphere (22 in total), independently of the slice thickness. Our tools can be used as a substitute for
ex vivo
magnetic resonance imaging (MRI), which requires access to an MRI scanner,
ex vivo
scanning expertise, and considerable financial resources. We tested our tools on synthetic and real data from two NIH Alzheimer’s Disease Research Centers. The results show that our methodology yields accurate 3D reconstructions, segmentations, and volumetric measurements that are highly correlated to those from MRI. Our method also detects expected differences between
post mortem
confirmed Alzheimer’s disease cases and controls. The tools are available in our widespread neuroimaging suite “FreeSurfer” (https://surfer.nmr.mgh.harvard.edu/fswiki/PhotoTools).
Modulation of alpha oscillations by attention is predicted by hemispheric asymmetry of subcortical regions
Authors: Ghafari Tara , Mazzetti Cecilia , Garner Kelly , Gutteling Tjerk , Jensen Ole
Published: March 2024

Evidence suggests that subcortical structures play a role in high-level cognitive functions such as the allocation of spatial attention. While there is abundant evidence in humans for posterior alpha band oscillations being modulated by spatial attention, little is known about how subcortical regions contribute to these oscillatory modulations, particularly under varying conditions of cognitive challenge. In this study, we combined MEG and structural MRI data to investigate the role of subcortical structures in controlling the allocation of attentional resources by employing a cued spatial attention paradigm with varying levels of perceptual load. We asked whether hemispheric lateralization of volumetric measures of the thalamus and basal ganglia predicted the hemispheric modulation of alpha-band power. Lateral asymmetry of the globus pallidus, caudate nucleus, and thalamus predicted attention-related modulations of posterior alpha oscillations. When the perceptual load was applied to the target and the distractor was salient caudate nucleus asymmetry predicted alpha-band modulations. Globus Pallidus was predictive of alpha-band modulations when either the target had a high load, or the distractor was salient, but not both. Finally, the asymmetry of the thalamus predicted alpha band modulation when neither component of the task was perceptually demanding. In addition to delivering new insight into the subcortical circuity controlling alpha oscillations with spatial attention, our finding might also have clinical applications. We provide a framework that could be followed for detecting how structural changes in subcortical regions that are associated with neurological disorders can be reflected in the modulation of oscillatory brain activity.
Lesions in a songbird vocal circuit increase variability in song syntax
Authors: Koparkar Avani , Warren Timothy L. , Charlesworth Jonathan D. , Shin Sooyoon , Brainard Michael S. , Veit Lena
Published: March 2024

Complex motor skills like speech and dance are composed of ordered sequences of simpler elements, but the neuronal basis for syntactic ordering of individual actions into sequences is poorly understood. Birdsong is a learned vocal behavior composed of syntactically ordered sequences of individual syllables. Activity in song premotor nucleus HVC (proper name) has been linked to the control of syllable sequencing, but sequencing may also be affected by its recurrent inputs. We here test the contribution of one of HVC’s inputs, mMAN (
medial magnocellular nucleus of the anterior nidopallium
), to the variable songs of adult male Bengalese finches (
Lonchura striata domestica
). The syntax of Bengalese song includes several patterns: 1)
chunks
, where syllables follow stereotypical order 2)
branch points
, where a given syllable can be followed by two or more different syllables in a probabilistic manner and 3)
repeat phrases
, where an individual syllable is repeated a variable number of times. We found that after bilateral lesions of mMAN, the acoustic structure of syllables remained largely intact, but sequencing became more variable for each of these patterns, seen by ‘breaks’ in previously stereotyped chunks, increased uncertainty at branch points and increased variability of repeat numbers. This increase in sequencing variability highlights the potential importance of regions projecting to HVC in the ordering of vocal elements. Previous studies on zebra finches found little effect of mMAN lesions on their relatively stereotyped adult song. In contrast, our results suggest that mMAN contributes to sequencing the variable songs of Bengalese finches and highlight the utility of species with more complex song syntax in investigating neuronal control of ordered motor sequences.
Context dependent contributions of the direct and indirect pathways in the associative and sensorimotor striatum
Authors: Cuevas Nisa , Llanos-Moreno Argelia , Ramírez-Armenta Kathia I. , Alatriste-León Hector , Ramírez Jarquin Josué O. , Tecuapetla Fatuel
Published: March 2024

To determine whether the contributions of striatal projection neurons from the direct (dSPNs) and indirect (iSPNs) pathways of the basal ganglia to action selection and locomotion can be generalized across the associative (DMS) and sensorimotor (DLS) striatum we compared the optogenetic activation or inhibition of these pathways on different tests. We show that self-modulation of dSPNs or iSPNs in either compartment has opposite contributions to real-time place preference, and to selecting an action in the DMS but not in the DLS. During reward seeking displacements, activation of either pathway in both compartments, or inhibition of dSPNs in the DMS slows movement. During spontaneous displacements, dSPNs activation showed opposing effects depending on the compartment modulated. Remarkably, inhibition of either pathway in the DLS decreases while only iSPNs inhibition in the DMS facilitates these displacements. These findings support a model of opposite, complementary and undescribed contributions of the striatal pathways depending on the compartment and context.
Suitability and Carrying Capacity of Aquatic Environment for Shrimp Culture in Sarjo District, Pasangkayu Regency West Sulawesi
Authors: Tamsil Andi , Hasnidar  , Harlina  , Asbar  , Ihsan. Ihsan
Published: March 2024

The potential of coastal and marine resources in Indonesia is so diverse both in terms of quantity and quality, should be able to contribute greatly to the economic growth of the State of Indonesia. The purpose of this stydy is to assess the level of land suitability and carrying capacity of the pond environment for shrimp culture in Sarjo District Pasangkayu Regency. The research was conducted using survey method, measuring biological, physical and chemical parameters. The observed data consisted of temperature, turbidity, TSS, current direction and speed, tides, pH, salinity, dissolved oxygen, ammonia, nitrate, nitrite, phosphate, BOD, COD, BOT, and plankton. Based on biological, physical and chemical data, an analysis of the suitability of the pond area was carried out using the geographic information system (GIS) Arc View GIS Application Version 3.3. The results of the level of suitability of land for shrimp culture in Sarjo District was very suitable 154.88 hectare; 2) Suitable 77.16 hectare and quite suitable 27.26 hectare. Overall land for aquaculture in each area is traditional 732.95 hectare, semi-intensive 1,589.12 hectare and intensive 247.83 hectare. The environmental carrying capacity of intensive shrimp cultivation ponds with an estimated maximum production of 42.63 tons ha-1, with a permitted pond area that does not exceed the environmental carrying capacity is 166.07 ha; semi-intensive cultivation with a maximum production of 153.49 tons ha-1 MT-1, the permitted pond area so as not to exceed the environmental carrying capacity is 597.85 hectare, traditional cultivation with a maximum production of 3.4 tons MT-1 with a supported pond area of 2,569 ha in Sarjo District, Pasangkayu Regency.
Evaluation of In vitro Anti-Diabetic Properties of Biosynthesized Magnesium Oxide Nanoparticles from Vernonia amygdalina (Bitter Leaf) Aqueous Leaf Extract
Authors: Afuye O. O. , Omotayo S. O.
Published: March 2024

Introduction: Vernonia amygdalina is a common shrub that is widely used and extracts from them have been traditionally used as remedies for treating diabetes mellitus in various parts of the world. The use of V. amygdalina to synthesize MgO nanoparticles has been used for various biomedical applications and it is compatible with anti-diabetic studies. This research investigates the in vitro anti-diabetic potentials of biosynthesized from aqueous V. amygdalina leaf extract.
Methodology: Aqueous extract of V. amygdalina-MgO nanoparticles were characterized using Fourier Transform Infrared, X-ray Diffraction and Scanning Electron Microscopy techniques. FTIR validated the presence of functional groups, the crystallization and size (66nm) of the nanoparticles was validated by XRD while SEM confirmed the shape of the nanoparticles synthesized.
Result:  Qualitative screening confirmed the presence of saponin, flavonoids, phenols, alkaloids, tannins, terpenoids, glycosides while their concentrations were evaluated quantitatively. V. Amygdalina-MgONPs extract and acarbose showed significant inhibition of α-amylase and α-glucosidase, with IC50 values of 55.05% and 20.0% respectively.
Conclusion: The study found that biosynthesized MgONPs-V. amygdalina aqueous extract has strong anti-diabetic properties, indicating its potential for diabetes treatment and management.
Molecular Characterization of Plasmid-mediated Quinolone Resistant Salmonella typhi From Patients Attending Federal Medical Center, Jabi, Abuja, Nigeria
Authors: Fasema, R  , Ngwai, Y. B  , Ishaleku, D  , Nkene, I. H  , Abimiku, R. H  , Tama, S. C  , Igbawua, I. N
Published: March 2024

Aims: This study investigates and reports the detection of qnr genes (plasmid-mediated quinolone resistance PMQR) in S.typhi isolated from stool of patients with suspected typhoid fever, in Federal Medical Center, Jabi, Abuja, Nigeria.
Study Design:  Cross sectional study.
Place and Duration of Study: Department of Microbiology, Nasarawa State University, Keffi, between October 2022 and November 2023.
Methodology: Salmonella typhi was isolated from stool of patients with suspected typhoid fever using standard culture and microbiological methods. Antibiotic susceptibility testing were performed  using  the  disc  diffusion method  to  investigate  the  ability  of  S.  typhi to resist some antibiotics. Qnr genes (qnrC,qnrD,qnrS) were detected by PCR and amplification.
Results: 17 out of 150 (11.3%) of the samples collected had S.typhi. Antibiotic resistance in the isolates in decreasing order were as follows: cefotaxime (100.0%), amoxicillin/ clavulanic acid (94.1%), nalidixic acid (94.1%), cefuroxime (94.1%), imipenems (88.2%), ceftriaxone/sulbactam (82.4%), ciprofloxacin (82.4%), gentamicin (58.8%), levofloxacin (47.1%) and ofloxacin (29.4%).The commonest antibiotic resistant phenotype was AUG- CTX-IMP-OFX-CN-NA-CXM-CRO-CIP-LBC at 29.4%. Multiple antibiotic resistance (MAR) was observed in 100% (17/17) of the isolates with the common MAR indices being 1.0 (29.4%), 0.7 (23.5%), 0.8 (17.6%) and 0.5 (17.6%). 33.3% of the isolates in FMCJ were positive for qnrC,qnrD,qnrS,qnrA+qnrC and qnrS+ aac(6′)-Ib-cr as all of qnrC qnrD,and qnrS genes were all expressed in the isolates.
Conclusion: The S.  typhi isolates showed lower resistances to ofloxacin, levofloxacin, and gentamicin, and all isolates were MAR, with resistance to 10 antibiotics being the most predominant. In addition, qnrC,qnrD, and qnrS resistance genes were all expressed in the isolates.
Effect of Selected Leaf Extracts on the Mycelial Radial Growth of Phytophthora sp. Causing Corm Rot of Colocasia (Colocasia esculenta L.)
Authors: Nirmala Divi Niharika , Lal Abhilasha A. , Simon Sobita
Published: March 2024

In the present study the pathogenicity of Phytophthora sp. causing corm rot of colocasia was proved by Koch’s postulates. Sixteen infected corm samples were collected from different markets in two districts (West Godavari and East Godavari) of Andhra Pradesh and pot experiment was carried out in the Department of Plant Pathology, SHUATS, Prayagraj during Rabi season (2022-23).  Out of those, the sample which collected from Kovvur Rythu Bazar, West Godavari district in Andhra Pradesh shows high pathogenicity. Five leaf extracts viz., neem, mint, lantana, tulsi and periwinkle @ 5, 10 and 15% concentrations were evaluated by using poisoned food technique against Phytophthora sp. Among all the leaf extracts, neem leaf extract @ 5, 10 and 15% concentrations recorded minimum radial growth (26.43, 24.73 and 22.77 mm, respectively) and maximum per cent inhibition (33.27, 37.59 and 42.55%, respectively) of Phytophthora sp. at 120 hrs of incubation as compared to other leaf extracts, treated (Metalaxyl) and untreated checks. The present study is limited to one trial in Prayagraj conditions, therefore to substantiate the present results more such trials are required in future for further recommendation.
Genetic Divergence Analysis of Wheat (Triticum aestivum L.) Genotypes
Authors: Singh Jay , Maurya C.L. , Gupta Rishabh , Kumar Sunil , Chaturvedi Shivam , Singh Ajay Pratap , Sachan Dhruvendra Singh
Published: March 2024

A laboratory experiment was carried out with 30 indigenous genotypes of bread wheat along with three checks in a complete randomized design for divergence analysis. The trial was conducted at Seed Technology laboratory of Acharya Narendra Deva University of Agriculture and Technology Kumarganj, Ayodhya during 2020-21. The observations were recorded on thirteen-character Test weight (1000-grain weight), seed width (mm), seed length (mm), shoot length, root length, seedling length, seedling dry weight, germination (%), first count, final count, vigour index-I, vigour index-II. The 30 genotypes grouped into 5 clusters resulted in cluster I and V emerging with highest number of entries as both were constituted by 9 entries followed by Cluster III having 6 genotypes and cluster II and VI having 4 genotypes respectively. The maximum intra cluster distance was estimated in the case of Cluster II (2.630) followed by cluster I (2.618), Cluster III (2.545), cluster IV (2.512), and cluster V (2.148). The highest inter-cluster distance was observed between clusters III and IV (6.062) Followed by clusters III and V (4.632), II and IV (4.489), cluster II and V ( 4.304). The minimum inter cluster was observed between II and III (3.317) followed by cluster IV and V ( 3.337) and cluster I and V (3.404). The cluster mean of 13 different characters for most of the character's highest cluster mean was observed in clusters IV and V and lowest cluster mean observed in cluster III and II.
Effect of Integrated Nutrient Management on Nutrient Availability Dynamics in Laboratory-incubated Black Clay Soil
Authors: Venkatesh Ili , Anantha Krishna Chaitanya , Raju B. , Revathi P.
Published: March 2024

Nutrient release in different soils is a dynamic process influenced by a multitude of factors, including soil texture, structure, organic matter content, pH, microbial activity, and nutrient management practices. An incubation study was conducted to study the nutrient availability and their release at different days after incubation through nutrient management practices. The results of the study revealed that at 15 DAI, available nitrogen and its fraction, available sulphur were recorded higher in the treatment receiving soil test based NPK, at 30 DAI in the treatment with integrated application 100% RDF, FYM and biofertilizers, at 45 and 60 DAI treatment receiving 75% soil test based NPK, FYM and biofertilizers. Available phosphorus recorded content recorded higher in the treatment with integrated application 100% RDF, FYM and biofertilizers and it continued to increase upto 45 DAI and their after its content decreased slightly to 60 DAI. Similar to available phosphorus, available potassium content also recorded higher in the treatment with integrated application 100% RDF, FYM and biofertilizers and it continued to increase upto 60 DAI. Treatments receiving sole inorganic fertilizers exhibited early decline in nutrient content whereas integrated treatments maintained the nutrient availability more than the sole inorganic fertilizers applied treatments.
Impact of Fault Resistance on Distance Relaying of Ahoada-Yenagoa Transmission Line Using Neplan
Authors: Ainah Priye Kenneth , Ugemuge Sunday
Published: March 2024

Relay protection schemes play a vital part in guaranteeing reliability and integrity of electrical power networks by promptly detecting and isolating faults in the transmission network. Fault resistance encountered during a fault event, is a crucial parameter that significantly influences the effectiveness of relay protection systems. This paper investigates the performance of a distance relying system under different fault resistance using NEPLAN software environment on a 46-km Ahoada to Yenagoa transmission line. The performance of the distance protection relaying system under single line to ground (SLG) at 80% of the transmission line with fault resistances of 0.65Ω and 2.9Ω was modeled and analyzed using NEPLAN. From our investigation, the result reveal that when a fault resistance of 0.65 Ω and 2.9 Ω was introduced in the system during a SLG at 80% of the line (zone 1), the apparent impedance seen by the relay increased from 5.475 Ω without fault resistance to 5.602Ω and 6.407 Ω respectively. The results show that for a fault resistance of 0.65 Ω, the apparent impedances (ZAPP) trajectory falls inside the impedance characteristic of zone 2 instead of zone 1 while a fault resistance of 2.9 Ω fall outside zone 2. The findings highlight the significance of fault resistance in transmission line relaying for distance protection.
Elektronengruppen im periodischen System der Elemente in der statistischen Theorie des Atoms
Authors: Tietz T.
Published: May 2007

Im Anschluß an eine Arbeit von Theis geben wir hier eine analytische Formel für die untere Grenze der Z‐Werte, bei der s‐, p‐, d‐, f‐Elektronen erstmalig in Erscheinung treten. Unsere analytische Formel gibt die Ordnungszahlen, bei welchen mit dem Einbau der s‐, p‐, d‐, f‐Elektronengruppen begonnen wird; recht befriedigend wieder. Weiter ergeben die numerischen Resultate für die Gesamtzahl der Elektronen im Atom gute Mittelwerte über die empirischen Zahlen. Die Gesamtheit der Elektronen im Atom ist in einer Tabelle dargestellt.
Theorie der Diffusionswellen. II (Amplifikationsbedingungen in Niederdruckentladungen)
Authors: Rother H.
Published: May 2007

Im Rahmen einer vorher entwickelten Theorie wird gezeigt, daß diffusionsbestimmte Amplifikationsprozesse (laufende Schichten usw) in Gasentladungen nur in Strombereichen auftreten, in denen Trägererzeugung oder Wandverluste nicht mehr proportional zur Elektronenkonzentration zunehmen. Abweichungen dieser Art in der Trägererzeugung sind möglich, wenn Stufenionisation einen merklichen Anteil der Trägerbilanz ausmacht und noch keine Sättigung der Konzentration angeregter Atome eingetreten ist. Hierfür kommen Stromstärkebereiche zwischen ≈ 1 mA und etwa 10 A in Frage, je nach Gasdruck und ‐art in Übereinstimmung mit dem experimentellen Befund. Bei sehr kleinen Stromstärken (< 1 mA) treten laufende Schichten auf, sobald die subnormale Entladungsform ne ⪅ ν realisiert ist, für die nach Ecker die Wand‐Diffusion wegen Abweichung von der Quasineutralität genähert proportional ne (1 + ν/ne) Damb verlaufen sollte.

Eine nähere Diskussion von Dispersionskurve, Resonanzkurve und Existenzgrenzen ermöglicht Aussagen über eine Reihe von experimentell bisher nur schwer zugänglichen Bestimmungsstücken des Plasmas.

Bei hohen Drucken (4 π e ne Ue/E2 < 1) existieren keine diffusionsbestimmten Amplifikationsprozesse, wenn ausschließlich Elektronen und positive Ionen für die Trägerbilanz eine Rolle spielen.

Ein möglicher diffusionsbestimmter Mechanismus, der auch hier erhebliche Feldüberhöhungen erzeugen kann und eventuell für die Erniedrigung der Durchschlagsspannung bei hohen Drucken verantwortlich zu machen ist, wurde kürzlich diskutiert.
Free Volume Approach to Polysiobutylene melt Viscosity under Pressure
Authors: Singh Harkrishan
Published: May 2007

The Doolittle melt viscosity expression ν = A eB/f has been applied to published data on polyisobutylene to calculate a parameter aP which is defined as the ratio of relaxation times at any pressure P to those at a reference pressure. To check the results, the parameter aP has also been calculated by the method of reduced variables. The agreement between the theoretical and experimental values of aP is found to be very good. Also the treatment separates melt viscosity of polyisobutylene into two factors, A dependents only on structural parameters, and f, which is determined by the specific volume is a function of temperature and pressure.
On the Statistical Theory of Nonequilibrium Processes
Authors: Magalinskij V. B. , Terletskij Ja. P.
Published: May 2007

A general method is worked out on the basis of principles of Gibbs' statistical mechanics which allows to find stationary probabilities and transition probabilities for physical quantities provided either the behaviour of their mean values or the general form of corresponding equations of motion (Langevin equations) is known.

The proposed method is free from ordinary restrictions of the theory of fluctuations and Brownian motion, such as, modest fluctuations, linearity of phenomenological equations, Markov's character of the random process and is applicable also to postacting systems.

The method is applied to some physical systems.

For the system, described by a non‐linear equation of motion the general coordinate‐velocity equation of motion of the transition probability density is obtained. This equation coincides with the well‐known Einstein‐Fokker‐Plank coordinate‐velocity equation in the case of linear friction law. The diffusion equation is obtained for the electrical circuit consisting of capacity and nonlinear resistance. Its general solution is found.
Beiträge zur Klärung des Mechanismus des Doppelkathodeneffektes
Authors: Badareu Eugen , Popescu Iovitzu , Iova Iancu
Published: May 2007

In der vorliegenden Arbeit werden eine Reihe von theoretischen und experimentellen Ergebnissen gegeben bezüglich der Vorgänge, welche bei Glimmentladungen in Argon an doppelter und einfacher Kathode stattfinden. Es wird die Wichtigkeit der Rolle unterstrichen, welche der Resonanzumladungsprozeß in der Kinetik der positiven Ionen in eigentlichen Gasen und, im besonderen, in der Theorie des Kathodenfalls spielt. Es wird auch gezeigt, wenigstens in den Bedingungen anomaler Entladungen, daß ein Großteil der Anregungen und Ionisierungen vor der Kathode in negativem Licht stattfinden, wobei diese Formation ein praktisch äquipotentiales Plasma darstellt, das von Primärelektronen durchzogen und unterhalten wird.
Zum Übergangseffekt der neutronenauslösenden Komponente der kosmischen Strahlung in Blei
Authors: Hauser I.
Published: May 2007

Mit borbeladenen Agfa K3‐Kernemulsionen wurde die Neutronenerzeugung durch die kosmische Strahlung in Blei bis zu 2,4 cm Dicke gemessen. Die mit der verwendeten Absorberanordnung erhaltenen Ergebnisse zeigen einen glatten Verlauf der integralen Neutronenerzeugungskurve entsprechend einer exponentiellen Abnahme der erzeugenden Strahlung. Ein Hinweis auf ein früher von anderer Seite angegebenes Maximum zwischen 1–2 cm Blei konnte nicht festgestellt werden.
Zum Übergangseffekt der sternauslösenden Komponente der kosmischen Strahlung in Blei
Authors: Hauser I. , Landrock P. , Lanius K. , Mitrani L. , Peeva A.
Published: May 2007

Der Übergangseffekt der sternerzeugenden Komponente der kosmischen Strahlung wurde hinter Blei in 3000 m Höhe untersucht. Ein Maximum der Sternhäufigkeit hinter 1–2 cm Pb wurde nicht beobachtet. Dieses Ergebnis befindet sich in Übereinstimmung mit den theoretischen Erwartungen.
Die Energieübertragung in lumineszierenden Lösungen. I. Lösungen mit einer gelösten lumineszierenden Substanz
Authors: Bothe H. K.
Published: May 2007

Die von Kallmann u. Fürst abgeleitete Funktion für die Konzentrationsabhängigkeit der Lumineszenzintensität flüssiger Lösungen wird so verallgemeinert, daß sie auch für die festen Polystyrol‐Lösungen Gültigkeit gewinnt. Aus dem charakteristischen Unterschied zwischen der Konzentrationsabhängigkeit der Lumineszenzintensität fester und flüssiger lumineszierender Lösungen bei Anregung mit energiereicher Strahlung werden Schlüsse auf die Art des Mechanismus der Energieübertragung vom Lösungsmittel auf die gelösten lumineszierenden Moleküle gezogen.
Zur Theorie der Wechselschichten aus schwachabsorbierenden Substanzen und ihre Verwendung als Interferometerspiegel
Authors: Koppelmann G.
Published: May 2007

Es wird mit Hilfe der Matrizenmethode die Absorption von λ/4‐ und λ/2‐Wechselschichten aus schwachabsorbierenden, dielektrischen Substanzen berechnet. Ferner wird der Einfluß der Absorption bei Verwendung dieser Schichten als Interferometerspiegel untersucht.
Diffusionstheorie der unter Beteiligung verschiedenartiger aktiver Zentren verlaufenden Kettenreaktionen
Authors: Sayasov Y. , Sayasov S.
Published: May 2007

Es wird die allgemeine Lösung eines Systems der kinetischen Diffusionsgleichungen gegeben, die insbesondere für die chemischen, unter Beteiligung verschiedenartiger aktiver Zentren (a. Z.) verlaufenden Kettenreaktionen gilt. Dabei werden die allgemeinen Randbedingungen berücksichtigt, die den Einfang der a. Z. auf die Wände des Reaktionsvolumens beschreiben. Die Anwendung dieser mathematisch strengen Methode auf die Wasserstoff‐Kettenoxydation zeigt, daß die gewöhnlich benutzte Semenov‐Methode der Integration der kinetischen Gleichungen in manchen Fällen falsch sein kann.
Die Bewegungsgleichungen eines speziellen Zweikörperproblems
Authors: Hess S. , Tischer M.
Published: May 2007

In der Vorliegenden Arbeit werden die Bewegungsgleichungen eines Zweikörpersystems, das aus einem Körper in einer rotierenden Hohlkugel besteht, errechnet. Dieses Problem wurde von H. Thirring aufgeworfen und als Einkörperproblem behandelt. Die hier bei der Durchrechnung als Zweikörperproblem erhaltenen Resultate sind sowohl in bezug auf den Gültigkeitsbereich als auch dem Gehalt nach als eine Erweiterung der von Thirring aufgestellten Bewegungsgleichungen anzusehen. Wie zu erwarten, treten im Innern der rotierenden Hohlkugel neben der Newtonschen Massenanziehung Coriolis‐ und Zentrifugalfelder auf.
Messungen der Sekundärelektronenemission an KCl und KBr
Authors: Petzel Bernhard
Published: May 2007

Nach der Methode der Einzelimpulse werden Messungen der Sekundärelektronenemission an KCl‐ und KBr‐Einkristallen sowie an einer KCl‐Aufdampfschicht vorgenommen. Die gemessenen Ausbeutewerte werden mit der aus der Dekkerschen Theorie sich ergebenden Abhängigkeit der Ausbeute von der Temperatur verglichen. Bei hoher Energie Ep der Primärelektronen nimmt δ mit zunehmender Temperatur zwischen Zimmertemperatur und 300 °C etwa umgekehrt proportional mit der Wurzel aus der absoluten Temperatur ab. Bei kleinen Primärenergien ist die Ausbeute temperaturunabhängig. Die Energieverteilung der Sekundärelektronen hängt von der Primärelektronenenergie ab, und zwar nimmt die Zahl der Elektronen mit niedrigen Energien bei Erhöhung der Primärenergie im Verhältnis zur Anzahl der übrigen Elektronen zu.
Das Sommerfeldsche Integral und die Lösung von Beugungsaufgaben in Winkelgebieten
Authors: Malyughinetz G. D.
Published: May 2007

Das Sommerfeldsche Integral als Fouriersche Darstellung des Wellenfeldes, das auf winkelförmigem Gebiet analytisch fortgesetzt ist. Die Umkehrungsformeln und ihre Anwendungen an verschiedenen Beugungsaufgaben in Winkelgebieten.
Über die allgemeine Form der Fortpflanzungsgesetze der Stoßwellen des Gravitationsfeldes
Authors: Treder H.
Published: May 2007

Bei der von Stellmacher angegebenen Form der Fortpflanzungsgesetze für die Störungen des Gravitationsfeldes wird eine Darstellung der Diskontinuitätsfläche vorausgesetzt, bei der der Betrag des Flächennormalvektors stationär ist. Es wird hier die allgemeine Form der Fortpflanzungsgesetze hergeleitet, die unabhängig von der speziellen Darstellung der Sprungfläche ist.
Zur Frage der Existenz von singularitätsfreien Lösungen der allgemein‐relativistischen Feldgleichungen, die Teilchenmodelle darstellen könnten. II
Authors: Papapetrou A. , Treder H.
Published: May 2007

Es werden Riemannsche Raum‐Zeit‐Welten untersucht, in denen es asymptotische Nullhyperflächen gibt, die, ähnlich wie die Schwarzschildsche Fläche r=2 m, ganz im räumlich Endlichen verlaufen. Es wird gezeigt, daß es in diesen Räumen geodätische Strahlen mit endlichen (von Null verschiedenen) Gesamtlängen gibt und die Räume daher topologisch inkomplett sind. Ferner wird gezeigt, daß auch bei Zulassung solcher inkompletten Räume die in Teil I bewiesene Nichtexistenz von singularitätsfreien, zeitlich‐periodischen Lösungen der Einsteinschen Gravitationsgleichungen bestehen bleibt.
Gasentmischungsvorgänge in Wechselstromglimmentladungen
Authors: Deutsch H.
Published: May 2007

Es wird eine durch den Durchgang eines Wechselstromes in einem Gasgemisch auftretende Entmischung in Abhängigkeit von der Frequenz des Entladungsstromes (50 Hz, 400 Hz und 540 kHz), den Dimensionen des Entladungsrohres, der Stromstärke, dem Gesamtgasdruck, dem Partialdruck des Zusatzgases und der Gasart untersucht.
Hall‐Effekt und Leitfähigkeit von Germanium‐Aufdampfschichten
Authors: Eckart F. , Jungk G.
Published: May 2007

Leitfähigkeits‐ und Hall‐Effektmessungen an dünnen bei 10−5 Torr auf Glasträger bei 450 °C aufgedampften Ge‐Schichten zeigen unabhängig vom Ausgangsmaterial ausnahmslos p‐Leitung mit einer Trägerdichte von 1018 bis 1019 cm−3. Die Beweglichkeit der Defektelektronen ist um 1–2 Größenordnungen geringer als im einkristallinen Ausgangsmaterial. Der Hall‐Koeffizient nimmt im Gegensatz zu den Ergebnissen an kompaktem p‐Material an dünnen Schichten mit der magnetischen Feldstärke zu.
Die Winkelabhängigkeit der magnetfeldinduzierten Anisotropie im Eisen‐Nickel‐Ferrit‐Einkristall
Authors: Wagner Rolf
Published: May 2007

Behandelt man Ferritmaterialien bei höheren Temperaturen im Magnetfeld, dann erhält man unter gewissen Voraussetzungen eine Orientierungsüberstruktur, die zu einer einachsigen magnetischen Anisotropie führt. Diese Anisotropie war Gegenstand der vorliegenden Untersuchung an einem Fe–Ni‐Ferrit‐Einkristall. Zu dem Zweck wurde die Abhängigkeit des Drehmoments von der Richtung des bei der Glühung angelegten Magnetfeldes in der (100−). (110−) und (111)‐Ebene gemessen. Die experimentellen Ergebnisse werden mit entsprechenden Theorien von Néel, Taniguchi, Yamamoto und Iwata verglichen, die auf dem Modell der Pärchenbildung beruhen. Unter der Voraussetzung, daß dieses Modell zutrifft, kann gezeigt werden, daß sich die Pärchen beim vorliegenden Ferrit mit ihren magnetisch wirksamen Achsen ausschließlich in Richtung der Würfelkanten des kubischen Spinellgitters ausrichten.
Theory of Isotope Shifts in Heavy Atoms
Authors: Ionesco‐Pallas N. J.
Published: May 2007

A general theory is given for the isotope shift of energy levels in heavy atoms. The methods used here are based neither on the simple perturbation theory nor on the solution of the Darwin‐Gordon differential equations for the region inside the nucleus. It is sufficient to solve an integral equation from which result both the distortion effect of the wave function due to the spatial extension of the nucleus, and the specific nuclear effects of surface and deformation.

The screening effects of the electrons in the closed shells, the effect of nuclear compressibility as well as other effects ar also analyzed.

The article probably exhausts the main causes which account for the global effect of isotope shift. The values obtained theoretically for the isotopic constants of the nuclei, fairly well agree with the experimental ones.
Zur relativistischen Kosmologie
Authors: Pachner Jaroslav
Published: May 2007

Es werden die Grundlagen der relativistischen Kosmologie entwickelt, ohne den Materietensor zu verwenden. Den Ausgangspunkt bilden drei einfache und plausible Annahmen, von denen die dynamische Gleichung des Weltalls in voller Allgemeinheit abgeleitet wird. Die Gleichung wird dann zur Untersuchung von drei verschiedenen Welten angewandt. Dabei wird eine einfache Beziehung bestimmt, mit deren Hilfe die Frage beantwortet werden kann, ob das Weltall pulsierend oder bis ins Unendliche expandierend ist. Es wird weiter nachgewiesen, daß die kosmologische Konstante in Wirklichkeit das (1/8 π)‐Vielfache der in geometrischen Einheiten gemessenen Dichte der neu im Weltall vom Nichts entstehenden Masse darstellt und daß die de Sittersche Welt nicht leer, sondern voll von solcher ununterbrochen erschaffenen Materie ist. Der Zusammenhang der vorliegenden Untersuchung mit den Arbeiten von Friedman, Einstein und McCrea wird erörtert. Abschließend wird die Größe des sichtbaren Gebietes des Weltalls bestimmt und zur zahlenmäßigen Überprüfung der Hypothese von Hoyle und McCrea über die „steady‐state universe”︁ benützt.
Temperaturverhältnisse von siedenden Flüssigkeiten in Dewargefäßen
Authors: Donth E.
Published: May 2007

In siedenden verflüssigten Gasen in Dewargefäßen treten größere Überhitzungen auf (im Falle des Sauerstoffes bis zu 0,6 grd). An der Oberfläche findet man einen großen Temperaturgradienten (in Sauerstoff von der Größenordnung 0,1 grd/mm). Diese Erscheinungen wurden in verschiedenen Anordnungen (auch mit Heizern) untersucht. Für kleine Wärmestromdichten an der Flüssigkeitsoberfläche liefert eine einfache hydrodynamische Betrachtung den Temperaturverlauf in der Oberflächengrenzschicht und den Überhitzungsgrad der Flüssigkeit in Abhängigkeit von Stoffgrößen und der Wärmestromdichte an der Oberfläche. Es ergibt sich eine befriedigende Übereinstimmung mit dem experimentell bestimmten Temperaturverlauf in der Grenzschicht und dem beobachteten Überhitzungsgrad.
Group Transitions in Solid Luminophores
Authors: Kakushadze T. I.
Published: May 2007

As a result of the strong interaction of electrons with the lattice, the transition of the electrons from the principal zone to the zone of conductivity of the semiconductor involves a large number of electrons. In this process the energy necessary for the intershell transition is compensated by re‐arrangement of the other electrons of the group. Therefore the electron group transitions always occur isoenergetically and consequently non‐radiatively. Nearly all complex processes known at present to occur in solid luminophores can be explained in the light of a group transition of this kind.
Zur Theorie der Kernspaltung. IV. Der Einfluß der magischen Zahlen auf die Kernspaltung
Authors: Brunner Witlof , Paul Harry
Published: May 2007

Die von den Verfassern in früheren Arbeiten nacheinander entwickelten Vorstellungen zur Theorie der Kernspaltung werden systematisch dargestellt. Aus der Grundkonzeption einer schalenstrukturabhängigen Deformation der Bruchstücke „im Augenblick”︁ ihrer Trennung folgen magische Effekte für das Kernkraftpotential zwischen den beiden Fragmenten und die mittlere kinetische Energie der Bruchstücke, deren Zusammenspiel die beobachtete Spaltungsasymmetrie quantitativ verständlich macht. Zur Illustration wird die spontane Spaltung von Cf252 diskutiert. Weiterhin wird die Tatsache der symmetrischen Spaltung von Bi209 (durch Deuteronen) verständlich gemacht. Schließlich wird eine qualitative Erklärung für die bekannte Abschwächung der Spaltungsasymmetrie bei Erhöhung der Anregungsenergie des sich spaltenden Kerns auf der Grundlage der entwickelten allgemeinen Vorstellungen gegeben.
Sondenmessungen bei höheren Stromdichten in der positiven Säule einer Argonentladung
Authors: Hayess E. , Rademacher K.
Published: May 2007

Es werden in einer Argonentladung bei 8 cm Rohrdurchmesser und 0,1 Torr Fülldruck die Plasmaparameter höherer Stromdichten mittels Sonden untersucht. Die Entladung wird stationär betrieben. Mittels Sonden kann die Elektronentemperatur und die Trägerkonzentration über den Radius des Rohres ermittelt werden. Eine Messung nach der Zweisondenmethode liefert die Werte des Längsgradienten. Die Auswertung der Sondencharakteristiken wird nach zwei verschiedenen Methoden durchgeführt und zeigt, daß die Methode der Auswertung des Ionenstromteils nach Kagan im Rahmen der allgemein bei Sondenmessungen zu erwartenden Genauigkeit im Vergleich mit der Langmuir‐Methode befriedigende Übereinstimmung liefert.

Die Trägerkonzentration läßt sich gut durch eine Besselfunktion annähern, und die von Fetz eingeführte Randbedingung, die die Aufladung der isolierenden Rohrwand berücksichtigt, gibt die Messungen im Rahmen der hier möglichen Genauigkeit richtig wieder. Aus der Beziehung J = e N b_El wird durch Integration der Trägerkonzentration über den Rohrquerschnitt die Beweglichkeit berechnet. Die erhaltenen Werte stimmen gut mit den bei dreißigmal kleineren Stromdichten von Wojaczek und Rademacher gefundenen Werten überein. Weder in der Trägerverteilung noch im Radialpotential gelingt es, bei den gemessenen Entladungsströmen das Eigenmagnetfeld nachzuweisen. Die in der Literatur auftretenden Formeln für den Ionensättigungsstrom, die sich durch einen konstanten Faktor unterscheiden, werden überprüft. Eine Entscheidung zwischen den erhaltenen Beziehungen nach Kagan, Bohm, Burhop und Massey und nach Langmuir ist auf Grund unserer Messungen nicht möglich.