bluuebunny/crossref_metadata_2025_split huggingface dataset:
When Liquid Rays Become Gas Rays: Can Evaporation Ever Be Non-Maxwellian?
Authors: Nathanson Gilbert M. 
Published: June 2021

AbstractA rare mistake by Otto Stern led to a confusion between density and flux in his first measurement of a Maxwellian speed distribution. This error reveals the key role of speed itself in Stern’s development of “the method of molecular rays”. What if the gas-phase speed distributions are not Maxwellian to begin with? The molecular beam technique so beautifully advanced by Stern can also be used to explore the speed distribution of gases evaporating from liquid microjets, a tool developed by Manfred Faubel. We employ liquid water and alkane microjets containing dissolved helium atoms to monitor the speed of evaporating He atoms into vacuum. While most dissolved gases evaporate in Maxwellian speed distributions, the He evaporation flux is super-Maxwellian, with energies up to 70% higher than the flux-weighted average energy of 2 RTliq. The explanation of this high-energy evaporation involves two beautiful concepts in physical chemistry: detailed balancing between He atom evaporation and condensation (starting with gas-surface collisions) and the potential of mean force on the He atom (starting with He atoms just below the surface). We hope that these measurements continue to fulfill Stern’s dream of the “directness and simplicity of the molecular ray method.”
My Great Uncle
Authors: Templeton Alan 
Published: June 2021

AbstractWhen I was a child, my favorite relative without a doubt was my great uncle, Otto Stern, because he nearly always did exactly what he wanted, and he did very little else. Otto lived just 3 km away from us in a beautiful part of North Berkeley that is known for its fine views of San Francisco Bay, its pleasant prewar houses, and its many appealing gardens. I loved exploring Otto’s backyard because he left it completely untended. It gave me the feeling of walking into a fairy tale, far removed from the everyday world of rules and order.
Otto Stern’s Molecular Beam Method and Its Impact on Quantum Physics
Authors: Friedrich Bretislav , Schmidt-Böcking Horst 
Published: June 2021

AbstractMotivated by his interest in thermodynamics and the emerging quantum mechanics, Otto Stern (1888–1969) launched in 1919 his molecular beam method to examine the fundamental assumptions of theory that transpire in atomic, molecular, optical, and nuclear physics. Stern’s experimental endeavors at Frankfurt (1919–1922), Hamburg (1923–1933), and Pittsburgh (1933–1945) provided insights into the quantum world that were independent of spectroscopy and that concerned well-defined isolated systems, hitherto accessible only toGedankenexperiments. In this chapter we look at how Stern’s molecular beam research came about and review six of his seminal experiments along with their context and reception by the physics community: the Stern-Gerlach experiment; the three-stage Stern-Gerlach experiment; experimental evidence for de Broglie’s matter waves; measurements of the magnetic dipole moment of the proton and the deuteron; experimental demonstration of momentum transfer upon absorption or emission of a photon; the experimental verification of the Maxwell-Boltzmann velocity distribution via deflection of a molecular beam by gravity. Regarded as paragons of thoroughness and ingenuity, these experiments entail accurate transversal momentum measurements with resolution better than 0.1 atomic units. Some of these experiments would be taken up by others where Stern left off only decades later (matter-wave scattering or photon momentum transfer). We conclude by highlighting aspects of Stern’s legacy as reflected by the honors that have been bestowed upon him to date.
Otto Stern—With Einstein in Prague and in Zürich
Authors: Gutfreund Hanoch 
Published: June 2021

AbstractThe two years that Otto Stern spent with Albert Einstein in Prague and Zürich, between the spring of 1912 and the spring of 1914, can be viewed as his apprenticeship in theoretical physics. This chapter describes that formative phase in Stern’s scientific career, prior to his emergence as one of the greatest innovators in experimental physics.
Walther Gerlach (1889–1979): Precision Physicist, Educator and Research Organizer, Historian of Science
Authors: Huber Josef Georg , Schmidt-Böcking Horst , Friedrich Bretislav 
Published: June 2021

AbstractWalther Gerlach’s numerous contributions to physics include precision measurements related to the black-body radiation (1912–1916) as well as the first-ever quantitative measurement of the radiation pressure (1923), apart from his key role in the epochal Stern-Gerlach experiment (1921–1922). His wide-ranging research programs at the Universities of Tübingen, Frankfurt, and Munich entailed spectroscopy and spectral analysis, the study of the magnetic properties of matter, and radioactivity. An important player in the physics community already in his 20s and in the German academia in his later years, Gerlach was appointed, on Werner Heisenberg’s recommendation, Plenipotentiary for nuclear research for the last sixteen months of the existence of the Third Reich. He supported the effort of the German physicists to achieve a controlled chain reaction in a uranium reactor until the last moments before the effort was halted by the Allied Alsos Mission. The reader can find additional discussion of Gerlach’s role in the supplementary material provided with the online version of the chapter on SpringerLink. After returning from his detention at Farm Hall, he redirected his boundless elan and determination to the reconstruction of German academia. Among his high-ranking appointments in the Federal Republic were the presidency of the University of Munich (1948–1951) and of the Fraunhofer Society (1948–1951) as well as the vice-presidency of the German Science Foundation (1949–1961) and the German Physical Society (1956–1957). As a member of Göttinger Achtzehn, he signed the Göttingen Declaration (1957) against arming the Bundeswehr with nuclear weapons. Having made history in physics, Gerlach became a prolific writer on the history of physics. Johannes Kepler was his favorite subject and personal hero—as both a scientist and humanist.
100 Years Molecular Beam Method Reproduction of Otto Stern’s Atomic Beam Velocity Measurement
Authors: Gruppe Axel , Cerny Simon , Stiebing Kurt Ernst , George Cedric , Hoffmann Jakob , Ilg Maximilian , Müller Nils , Satar Alienza , Schobert Vincent , Weimer Leander , Dworak Markus , Engel Stefan , Rüschmann Gustav , Zimmer Viorica , Zanger Erich , Schmidt-Böcking Horst 
Published: June 2021

AbstractThe history of Otto Stern’s pioneering measurement of the Maxwell-Boltzmann velocity distribution of a Silver atomic beam performed 1919 in Frankfurt is described. It is shown how Albert Einstein influenced Stern in his research. This experimental apparatus is not any more existing; therefore it was reconstructed in the workshops of the Physics faculty of the Goethe University in Frankfurt. The experimental verification of Stern’s results was finally achieved by a team of Frankfurt high school students (Gymnasium Riedberg) under the supervision of their teachers Axel Gruppe and Simon Cerny. By fighting against a number of difficulties, they succeeded to get the reconstructed apparatus started and were able to reproduce the results from the early experiments of Stern.
Bound states of WIMP dark matter in Higgs-portal models. Part I. Cross-sections and transition rates
Authors: Oncala Ruben , Petraki Kalliopi 
Published: June 2021

Abstract
We investigate the role of the Higgs doublet in the thermal decoupling of multi-TeV dark matter coupled to the Weak interactions of the Standard Model and the Higgs. The Higgs doublet can mediate a long-range force that affects the annihilation processes and binds dark matter into bound states. More importantly, the emission of a Higgs doublet by a pair of dark matter particles can give rise to extremely rapid monopole bound-state formation processes and bound-to-bound transitions. We compute these effects in the unbroken electroweak phase. To this end, we consider the simplest renormalisable fermionic model, consisting of a singlet and a doublet under SUL(2) that are stabilised by a ℤ2 symmetry, in the regime where the two multiplets coannihilate. In a companion paper, we use the results to show that the formation of metastable bound states via Higgs-doublet emission and their decay decrease the relic density very significantly.
On the Spectra of Separable 2D Almost Mathieu Operators
Authors: Takase Alberto 
Published: June 2021

AbstractWe consider separable 2D discrete Schrödinger operators generated by 1D almost Mathieu operators. For fixed Diophantine frequencies, we prove that for sufficiently small couplings the spectrum must be an interval. This complements a result by J. Bourgain establishing that for fixed couplings the spectrum has gaps for some (positive measure) Diophantine frequencies. Our result generalizes to separable multidimensional discrete Schrödinger operators generated by 1D quasiperiodic operators whose potential is analytic and whose frequency is Diophantine. The proof is based on the study of the thickness of the spectrum of the almost Mathieu operator and utilizes the Newhouse Gap Lemma on sums of Cantor sets.
Design optimization of aircraft structures using virtual proving ground
Authors: Gorskii Yuriy , Gavrilov Petr , Nikitin Georgiy , Pautova Tatiana , Tamm Aleksandr 
Published: June 2021

AbstractThe main challenges of aerospace industry are increased flight range, fuel, and operating costs. There is an urgent need for more efficient design methods and rational use of composite materials in order to reduce the weight of the aircraft and increase strength and reliability. The use of optimization methods, modern software, and supercomputer technologies plays a key role in shortening the product development cycle. It allows many design options to be analyzed and compared in the early design stages. This paper presents an approach to using optimization methods in conjunction with virtual tests. The Virtual Proving Ground (VPG) includes Virtual Testbeds (VTB) such as “Aerodynamics,” “Statics,” and “Dynamics.” VPG provides end-to-end transfer of results and boundary conditions between blocks and systems of automated post-processing of the results. Thus, the results of the aerodynamic tests are transferred as input data for the static strength tests. The results of static and dynamic tests allow to perform multicriterion optimization considering different loading conditions. Automated post-processing allows to track the miscellaneous parameters at every testing stage. The aim of this work is to develop an approach to optimization of a composite structures using VPG. The presented approach was developed and tested on the example of the unmanned aerial vehicle.
Reduced cortical GABA and glutamate in high schizotypy
Authors: Kozhuharova Petya , Diaconescu Andreea O. , Allen Paul 
Published: June 2021

Abstract
Rationale
Abnormal functioning of the inhibitory gamma-aminobutyric acid (GABA) and excitatory (glutamate) systems is proposed to play a role in the development of schizophrenia spectrum disorder. Although results are mixed, previous 1H-magnetic resonance spectroscopy (MRS) studies in schizophrenia and clinical high-risk samples report these metabolites are altered in comparison to healthy controls. Currently, however, there are few studies of these metabolites in schizotypy samples, a personality dimension associated with the experience of schizophrenia and psychosis-like symptoms.

Objectives
We investigated if GABA and glutamate metabolite concentrations are altered in people with high schizotypy. We also explored the relationship between resilience to stress, GABA metabolite concentrations and schizotypy.

Methods
We used MRS to examine GABA and glutamate levels in the medial prefrontal cortex in people with low and high schizotypy traits as assessed with the Schizotypal Personality Questionnaire. Resilience to stress was assessed using the Connor-Davidson Resilience Scale.

Results
Compared to individuals with low schizotypy traits, high schizotypy individuals showed lower cortical prefrontal GABA (F (1,38) = 5.18, p = 0.03, η2 = 0.09) and glutamate metabolite levels (F (1, 49) = 6.25, p = 0.02, η2 = 0.02). Furthermore, participants with high GABA and high resilience levels were significantly more likely to be in the low schizotypy group than participants with low GABA and high resilience or high GABA and low resilience (95% CI 1.07–1.34, p < .001).

Conclusions
These findings demonstrate that subclinical schizotypal traits are associated with abnormal functioning of both inhibitory and excitatory systems and suggest that these transmitters are implicated in a personality trait believed to be on a continuum with psychosis.
Effect of drying on the hydroxyl accessibility and sorption properties of pressurized hot water extracted wood
Authors: Kyyrö Suvi , Altgen Michael , Seppäläinen Hanna , Belt Tiina , Rautkari Lauri 
Published: June 2021

AbstractHot water extraction (HWE) treatment changes the physicochemical properties of the wood, including hygroscopic properties. HWE treatment decreases the hydroxyl accessibility of the wood, but the relevance of other mechanisms that change hygroscopic properties are not fully understood. This study investigates the effect of drying on the hydroxyl accessibility and sorption properties of wood. Pressurized hot water extraction (HWE) treatment was applied at 140 °C for 1–5 h to Scots pine (Pinus sylvestris L.) sapwood samples in order to remove increasingly more hemicellulose from the cell wall matrix. Following HWE treatment, half of the wood samples were oven-dried and then re-soaked, while the other half was kept in a fully saturated state. The samples were investigated by applying a new approach that was based on the deuteration of accessible hydroxyl groups, which was followed by the measurement of mass loss due to re-protonation. Sorption properties of the wood samples were studied by measuring moisture content, sorption isotherms and dimensional changes. The present results showed that accessible hydroxyl group content decreased only due to hemicellulose removal during the HWE treatment and was unaffected by oven-drying. However, oven-drying enhanced the effect of HWE treatments in reducing the water-saturated dimensions and the moisture content of wood. Therefore, the additional reductions in hygroscopicity and water-saturated dimensions were not related to changes in sorption site density.
Plastic responses in the coral Pocillopora acuta to extreme low-light conditions with and without food provision
Authors: Fong Jenny , Poquita-Du Rosa Celia , Todd Peter A. 
Published: June 2021

AbstractThis study examines phenotypically plastic responses inPocillopora acutacollected from a highly urbanized reef environment to extreme low-light conditions. While among-species differences in how corals cope with low light are well documented, much less is known about within-species responses. It also remains unclear how extreme low light and provision of food may interact and influence coral physiology. Clonal fragments from six colonies (genotypes) ofP. acutawere subjected to two light treatments with mean midday irradiances of 4 and 40 μmol photons m−2 s−1photosynthetically active radiation (PAR), representing just 0.5 and 5% ambient light level, and were either fed with zooplankton or not fed for nine days. Corals maintained in 4 PAR had lower endosymbiont density but higher cellular chlorophyllaconcentration than those in 40 PAR. Feeding rates were similar in both light treatments and had no significant effects on endosymbiont density and chlorophyllaconcentrations. While genotypes varied in the level of phenotypic plasticity expressed for both photoacclimation and heterotrophy, most displayed similar directions in their responses, indicating photoacclimation inP. acutais broadly predictable. Our study demonstrates thatP. acutafrom Singapore is able to acclimate to very low-light conditions by adjusting their photophysiology, providing additional evidence that this species is resilient to urbanization-related stress.
Exploring impacts of marine heatwaves: paternal heat exposure diminishes fertilization success in the purple sea urchin (Strongylocentrotus purpuratus)
Authors: Leach Terence S. , BuyanUrt Buyanzaya , Hofmann Gretchen E. 
Published: June 2021

AbstractMarine heatwaves (MHWs) are projected to increase in intensity and frequency over the coming decades, and it is imperative to assess the adaptive capacity of marine organisms to these extreme temperature events. Given the nature of MHWs to last days to weeks in a region, these events may have overarching impacts on phenological events like reproduction and development. Here, the role of adult thermal history and transgenerational plasticity may be an important pathway by which MHWs are transduced to impact community structure. In this study, we sought to explore the effects of paternal thermal history in the purple urchin, Strongylocentrotus purpuratus, on a crucial aspect of reproduction, fertilization. Using ecologically relevant temperatures representative of both MHW events that occurred in 2014–2020 and non-MHW temperatures in our region of the California Large Marine Ecosystem, we conditioned male S. purpuratus for 28 days to either a high, MHW or a low, non-MHW temperature. Following the temperature acclimation of adults, sperm performance was tested for individual males by conducting fertilization success trials at varying temperatures and sperm concentrations. While sperm appeared robust to elevated temperature during fertilization, sperm produced by high-temperature-acclimated males had overall diminished performance as compared to those acclimated to non-MHW temperatures. These results suggest MHW events will have a negative impact on fertilization in situ for S. purpuratus populations. Furthermore, these results highlight the importance of considering both male and female environmental history in projections of reproduction under climate change scenarios.
Using complementary visual approaches to investigate residency, site fidelity and movement patterns of the dusky grouper (Epinephelus marginatus) in a Mediterranean marine protected area
Authors: Desiderà Elena , Trainito Egidio , Navone Augusto , Blandin Rémi , Magnani Luana , Panzalis Pieraugusto , Mazzoldi Carlotta , Guidetti Paolo 
Published: June 2021

AbstractAssessing individuals’ abundance, residency (presence at a site within a certain period) and site fidelity (tendency to return to the same site in subsequent seasons or years) is crucial for evaluating and improving the effectiveness of spatial conservation/management measures regarding ecologically and socio-economically valuable species. Using underwater visual census (UVC) and photo-identification (photo-ID) techniques, we estimated the abundance, residency and site fidelity of the dusky grouper, Epinephelus marginatus, at two protected sites within the Tavolara-Punta Coda Cavallo Marine Protected Area (Sardinia, Italy) in the summers of 2017–2018. The scope and spatio-temporal resolution of the study was extended by involving volunteer recreational divers in the photo collection. Grouper mean densities varied significantly across sampling dates, with a significant variability between the 2 years and the two investigated sites. At least 94 grouper visited the study sites in the summers of 2017–2018 based on the analysis of 968 high-quality photos using a semi-automated software to photo-identify individuals. Overall, the most frequently sighted grouper was recorded on 32 different days and 21 individuals (22%) identified in 2017 were re-sighted in 2018. The participation of volunteer recreational divers helped detect the inter-site (3.5–4 km apart) movements of a female and a male, supporting previous findings regarding the occurrence of reproduction-related movements. This study provides novel insights into the residency and site-fidelity patterns of the dusky grouper, and its small-scale movements probably related to reproduction. Specifically, we provide indications that effective protection from fishing should encompass the entire area used by grouper for reproductive movements.
Exposure to moderately elevated temperatures changes food preferences in the tropical marine herbivore Haliotis squamata
Authors: Mitterwallner Veronika , Suci An Nisa Nurul , Zamani Neviaty , Lenz Mark 
Published: June 2021

AbstractOcean warming is affecting marine ectothermic herbivores as well as the macroalgal species they consume and this has the potential to alter their trophic interaction. However, it is currently still unknown how these two important components of benthic food webs will react to a warming environment. Consumption rates of grazers change with increasing temperatures, but it is unclear whether this is also true for feeding preferences. In this study, multiple-choice feeding assays with the tropical abalone Haliotis squamata from Western Indonesia were conducted in August 2018. After brief acclimation of either the grazer or the macroalgae to moderately elevated water temperatures (maximum 2 °C above the long-term average) in the laboratory, three species of living macroalgae were simultaneously offered to the abalone in feeding assays. Consumption rates of H. squamata were lower under elevated water temperatures, while its feeding preference switched: At 27 °C (2 °C below long-term average), abalone preferred non-acclimated Gracilaria salicornia, but switched to non-acclimated Amphiroa spp. at 31 °C. Interestingly, no such switch in preference occurred when the macroalgae, but not the grazers were acclimated. This indicates that the grazer will presumably be the driver of this potential change in interactions between H. squamata and its macroalgal food. Ocean warming may result in changes in the structure of benthic communities, mediated by changes in the feeding behaviour of herbivorous invertebrates.
The popliteofibular ligament: a cadaveric ultrasound study
Authors: Pękala Przemysław A. , Mizia Ewa , Mann Mitchell R. , Wagner-Olszewska Ilona , Mostowy Marcin , Tatoń Grzegorz , Domżalski Marcin 
Published: June 2021

Abstract
Objective
The popliteofibular ligament (PFL) is an important stabilizer of the knee found within the posterolateral corner (PLC) of the joint. Injuries to the PLC can cause substantial patient morbidity. Accurate PFL visualization has been historically challenging, impeding injury diagnosis and treatment. The gold standard for in vivo PFL visualization is magnetic resonance imaging (MRI), but this procedure has slice thickness limitations, is costly, and is subject to longer wait times. Ultrasonographic (US) PFL assessment is a potentially viable alternative to MRI. This study aimed to determine the viability of US PFL assessment.

Materials and methods
Ten fresh-frozen lower limb specimens were evaluated for the presence and morphometric characteristics of the PFL via US using an 18.0-MHz linear transducer. The cadavers were then dissected and reassessed for the presence and morphometric characteristics of the PFLs for comparison with US findings. Moreover, the fracture of the fibular styloid process near the site of the insertion of the PFL (the arcuate sign) was simulated and assessed via US.

Results
The PFL was visualized and measured in all ten knees via both US and cadaveric assessments. There were no statistically significant differences in PFL morphometric characteristics determined via US examination and dissection. The fibular styloid fracture was easily identified in US examination.

Conclusion
US imaging is a viable alternative for accurate and effective assessment of the normal PFL. Moreover, the arcuate sign can be evaluated via US.