bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multiple photodetachment of atomic anions via single and double core-hole creation
Authors: Schippers S , Perry-Sassmannshausen A , Buhr T , Martins M , Fritzsche S , Müller A 
Published: July 2020

Abstract
We review the recent experimental and theoretical progress in K-shell detachment studies of atomic anions. On the experimental side, this field has largely benefitted from technical advances at 3rd generation synchrotron radiation sources. For multiple detachment of C−, O−, and F− ions, recent results were obtained at the photon-ion merged-beams setup PIPE which is a permanent end station at beamline P04 of the PETRA III synchrotron light source in Hamburg, Germany. In addition to a much increased photon flux as compared to what was available previously, the PIPE setup has an extraordinary detection sensitivity for heavy charged reaction products that allows one to study detachment processes with extremely low cross sections in the kilobarn range, e.g., for processes involving the simultaneous creation of two core-holes by a single photon as observed in the net triple detachment of F− and the net five-fold detachment of C−. Moreover, hitherto disregarded photodetachment resonances have been discovered, which exhibit a variety of line shapes. For O− the core-hole lifetime could be determined precisely from a high-resolution measurement of a photodetachment resonance. These experimental findings pose new challenges for state-of-the-art atomic theory and require calculations combining photoexcitation (ionization) with decay cascade processes that follow after initial core-hole production.
Fast, wafer-scale growth of a nanometer-thick graphite film on Ni foil and its structural analysis
Authors: Deokar Geetanjali , Genovese Alessandro , Costa Pedro M F J 
Published: July 2020

Abstract
The growth of graphite on polycrystalline Ni by chemical vapor deposition (CVD) and the microstructural relation of the graphitic films and the metallic substrate continues to puzzle the scientific community. Here, we report the wafer-scale growth of a nanometer-thick graphite film (∼100 nm, NGF) on Ni foil via a fast-thermal CVD approach (5 min growth). Moreover, we shed light on how localized thickness variations of the NGF relate to the Ni surface topography and grain characteristics. While on a macro-scale (mm2), the NGF film looks uniform—with a few hundred highly ordered graphene layers (d0002 = 0.335 nm), when studied at the micro- and nano-scales, few-layer graphene sections can be identified. These are present at a density of 0.1%–3% areas in 100
µ
m2, can be as thin as two layers, and follow an epitaxial relation with the {111} fcc-Ni planes. Throughout the 50 cm2 NGF, the sharp graphite/substrate interfaces are either composed of a couple of NiCx layers or a graphene layer. Moreover, the NGF was successfully transferred on SiO2/Si substrate by a wet chemical etching method. The as-produced NGFs could complement or offer an alternative to the mm-thick films produced from natural graphite flakes or polymer sheets.
Dynamically controlling electromagnetic reflection using reconfigurable water-based metasurfaces
Authors: Pang Yongqiang , Mo Manman , Li Yongfeng , Qu Bingyue , Xia Song , Qu Shaobo , Xu Zhuo 
Published: July 2020

Abstract
We proposed and demonstrated a reconfigurable water-based metasurface to achieve continuously dynamic control of electromagnetic (EM) reflection within a wide frequency band. The proposed metasurface is an array of an anisotropic unit cell consisting of two metallic layers separated by a dielectric layer. The flowing channel of the distilled water is designed in the dielectric spacer, so the metasurface is reconfigured by simply changing the injection quantity of water. Calculated, simulated and real-time measured results show that the reflection almost monotonically reduces as the water is injected into the metasurface, and the tunable level of reflection is larger than 10 dB from 8 to 18 GHz during the reconfiguring process. Besides the absorption resulting from the injected water, the EM reflection variation is partly contributed to the scattering mechanism. The results here provide an effective solution to flexibly control EM reflection from an object, and may find potential applications in the design of the adaptive EM surfaces and devices.
Effect of extrusion on damping and mechanical properties of Mg-Zn-Y alloy
Authors: Lu Ruopeng , Yao KeYu , Zhao Yuhong , Jiao Kai , Li Kun , Hou Hua 
Published: July 2020

Abstract
The damping and mechanical properties of extruded Mg-ZnX-Y1.33X (X = 1, 2, 3 at%) alloys were investigated in this experiment. The results shown that the alloy was mainly composed by long-period stacking ordered (LPSO) phase and magnesium(Mg) matrix. With the increase of Zinc(Zn) and Yttrium(Y) content, the grains had a certain refinement, the LPSO content was significantly increased, accompanied by a small amount of rare Y-enriched particles. After extrusion, the second phase of the alloys were broken into small pieces. The tensile strength(UTS) and yield strength(YS) of the alloy increased significantly, but the elongation decreased with the increase of LPSO phase. Mg-4.9Zn-8.9Y shown the best mechanical properties, with the tensile strength of 415 MPa, yield strength of 325MPpa, and elongation of 6.5%. Research on alloy damping performance shown that as the content of LPSO increases, the damping performance of as-cast alloys increased, and there is no obvious change after extrusion. It was due to a large number of dislocations entangled with work hardening, which greatly reduced the dislocation damping in magnesium alloys.
Invited Commentary: Reckoning With the Relationship Between Stressors and Suicide Attempts in a Time of COVID-19
Authors: Ettman Catherine K , Gradus Jaimie L , Galea Sandro 
Published: July 2020

Abstract
The coronavirus disease 2019 (COVID-19) pandemic presents a unique set of risk exposures for populations, which might lead to an increase in suicide. While large-scale traumatic events are known to increase psychological disorders, thus far the science has not shown a clear link between these events and suicide. In this issue of the Journal, Elbogen et al. (Am J Epidemiol. 2020;189(11):1266–1274) used representative data from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC) to show that 4 dimensions of financial strain—financial debt/crisis, unemployment, past homelessness, and lower income—are associated with subsequent suicide attempts. There are 3 main lessons we can take from Elbogen et al.: First, with populations facing record-breaking unemployment, economic recession, and reduced wages, we can anticipate an increase in suicide in the wake of the COVID-19 pandemic. Second, these data show the centrality of financial stressors, marking the current moment as distinct from other disasters or large-scale trauma. Third, the data teach us that financial stressors are linked and cumulative. In this way, Elbogen et al. provide a sobering harbinger of the potential effects on suicide of the collective stressors borne by the COVID-19 pandemic and other mass traumatic events that are accompanied by substantial financial stressors.
Molecular Phylogenetics of The Tody-Tyrant and Flatbill Assemblage of Tyrant Flycatchers (Tyrannidae)
Authors: Tello Jose G. , Bates John M. 
Published: July 2020

AbstractThe tody-tyrant and flatbill assemblage, sensuLanyon (1988a), includes 12 genera of tyrant flycatchers known variously as “tody-tyrants” and “flatbills.” Lanyon supported the monophyly of the group based on similar skull morphology and nest form, and built intergeneric relationships based on syringeal characters. However, these comparisons were made without a phylogenetic framework. A more recent study assessing relationships in the tyrant flycatchers using published morphological and behavioral data failed to recover monophyly of this assemblage (Birdsley 2002). Using DNA sequence data, we test for the monophyly of the tody-tyrant and flatbill assemblage and compare and contrast phylogenetic signals from mitochondrial and nuclear DNA character systems. We discuss our results in light of results from previous studies. We include representatives of the other major tyrant flycatcher assemblages for a total of 42 individuals (representing 27 tyrannid genera and 36 species). We sequenced 3,022 base pairs (bp) of three mitochondrial genes (ND2, ND3, and cytochrome b) and one nuclear intron (FIB5). Our results resolve many of the basal relationships of the tody-tyrant and flatbill phylogeny, but separate and combined analyses of data partitions are necessary to understand the nature of conflict among data sets. The tody-tyrants constitute a monophyletic clade, but the genera Hemitriccus and Lophotriccus are not monophyletic, and the limits of Oncostoma-Lophotriccus need to be revised with more complete sampling at the species level. The flatbills as defined by Lanyon are not monophyletic (Onychorhynchus and Platyrinchus are not true flatbills). Pseudotriccus and Corythopis are sister taxa and, together with Leptopogon and Mionectes, are allied to the tody-tyrant and flatbill clade.Filogenia Molecular del Grupo de los Picochatos y Mosquiteros de la Familia Tyrannidae
Feeding and Digestive Organ Size in Breeding Lesser Snow Geese
Authors: Ankney C. D. 
Published: July 2020

Abstract
The Lesser Snow Geese that nest at the McConnell River, Northwest Territories, feed heavily before arriving on the breeding grounds. During laying and early incubation, feeding declines to low levels but increases slightly during late incubation. After their eggs hatch the geese greatly increase their food intake. These changes in feeding activity are correlated with changes in the average sizes of four digestive organs (pancreas, liver, gizzard, and intestine). The large digestive organs characteristic of arriving and post-hatch geese are due to hyperphagia. Previously reported situations that produced decreased size of avian digestive organs did not account for that condition in incubating geese. The decrease in size of digestive organs during incubation is claimed to be innate; its evolution is discussed.
Composition of Eggs of Several Bird Species
Authors: Ricklefs Robert E. 
Published: July 2020

Abstract
This paper presents the lipid, nonlipid dry matter, and water contents of the eggs of the Starling, Coturnix Quail, Mourning Dove, Laughing Gull, and Mallard and compares the data with published accounts of the eggs of other species. The lipid level of the yolk and the percentage of yolk in the egg increase in direct relation to the precocity of the young at hatching. The high lipid content of the eggs of precocial species is related primarily to their long incubation periods, resulting in a larger total metabolic requirement than for the embryos of altricial species. The high water levels of the eggs of altricial species are a direct consequence of the high water levels of the chicks at hatching.
Avian Play
Authors: Ficken Millicent S. 
Published: July 2020

Abstract
Play is more difficult to distinguish from other activities in birds than in mammals. Some cases of play reported in the literature appear to be due to threshold lowering, a type of activity that is usually differentiated from play. The various types of avian play are reviewed. Like mammals, birds exhibit object manipulation and some types of locomotory play. Subsong shows some remarkable similarities with characteristics of nonvocal play as noted in mammals, and birds may engage in other types of acoustic activities with playlike features. The corvids, particularly the Common Raven, exhibit the most complex play known for birds, and these activities, which are part of the learning process in the young, are probably important in the species' adaptation to a wide variety of habitats. Of all animals, only birds and mammals play, and play evolved independently in the two groups probably because of similar selection pressures acting on the developmental process to produce flexibility of behavior and the perfection of certain motor skills.
Breeding Biology of the Savannah Sparrow on Kent Island
Authors: Dixon Clara L. 
Published: July 2020

Abstract
I studied the breeding biology of the Savannah Sparrow (Passerculus sandwichensis) on Kent Island, New Brunswick, Canada from 1964 through 1968. I estimated the breeding population to be 125-135 pairs $(412-445\ \text{individuals}/{\rm km}^{2})$. The mean number of nests produced per female, including those destroyed by predators, was 2.97. Clutch size ranged from 2 to 5. The mean clutch size based on 1,142 eggs in 284 nests of known clutch size was 4.02. Not only was the four-egg clutch most numerous but a greater percentage of eggs in the four-egg clutches hatched and the mean number of young fledged per nest was also highest. The mean incubation period was 12.2 days, the mean duration of nestling life was 9 days, and the approximate length of the breeding season as 52 days. The daily mortality rate of eggs was 11.9% and of nestlings 2.1%. Predation was the major factor affecting reproductive success; 50.5% of all nests located were destroyed by predators. The main nest predators were Common Crows and Herring Gulls. Of the nests destroyed by predators, 87.8% contained eggs rather than nestlings. The intense predation necessitated high nest replacement. The mean interval between the termination of one nest and the appearance of the first egg in the succeeding nest was 6.3 days. If successive nests are destroyed on the day incubation begins, it is hypothetically possible for a pair to produce four nests during a single breeding season; many birds in the population produce at least three. Although enough time was available for birds to fledge two broods in a season, few of them fledged more than one. Thus, the nesting success was low (success from egg to hatching 18.1%). High nest replacement compensated for high egg mortality, and an average of 2.16 young per pair were fledged per season.
Ontogeny of Vocalization in the Greater Rhea
Authors: Beaver Paul W. 
Published: July 2020

Abstract
The call-notes of the Greater Rhea chick were classified according to their acoustical structure and behavioral context. Both rate of vocalization and tonal quality of call-notes were found to deteriorate as a function function of maturation. Call-note production was completely eliminated by 7 weeks of age. Greater Rhea adults are silent except for such relatively infrequent vocalizations as "hissing" that sometimes accompanies agonistic behavior and a disyllabic "grunt" that only the male produces as part of a courtship display. Tracheal growth and a marked reduction in the intrusion of the internal tympanic membranes into the bronchial passages could contribute to the deterioration of vocalization. The use of vocalization as the primary channel of communication is replaced by visual display in the adults. These modalities are best suited to the ecological contingencies facing the chick and adult, respectively.
Hybridization between Gulls (Larus glaucescens and L. occidentalis) in the Pacific Northwest
Authors: Hoffman Wayne , Wiens John A. , Scott J. Michael 
Published: July 2020

Abstract
Interbreeding between Glaucous-winged Gulls (Larus glaucescens) and Western Gulls (L. occidentalis) occurs extensively within a 180-km zone along the Washington coast, producing a high frequency of intermediate morphs in breeding populations. We conducted intensive studies on Destruction Island, Washington, in the midst of the zone of hybridization. There over half of the breeding birds were phenotypically intergrades between pure Glaucous-winged and Western gulls in characters of iris and eye-ring coloration, mantle shade, and wing tip pattern. Mating patterns of Destruction Island gulls were assortative, individuals pairing with mates similar to themselves. Pairs composed of pure Glaucous-winged or Western gulls hatched significantly fewer eggs than pairs containing at least one hybrid individual. The greater apparent reproductive success of the intergrades would seem to be countered by the assortative mating patterns, possibly providing conditions sufficient to maintain an equilibrium system containing both pure types as well as intergrades. These conditions are explored in a simulation model that considered immigration, density-dependent fecundity, pairing and reproduction, and mortality. A stable colony of mixed composition may be maintained by a regular but small influx of pure types into the colony.
Juvenile Dispersal and Development of Site-Fidelity in the Black-Capped Chickadee
Authors: Weise Charles M. , Meyer John R. 
Published: July 2020

Abstract
Dispersal of young was studied in a non-migratory population of the Black-capped Chickadee (Parus atricapillus) in southeastern Wisconsin. Eighty-eight chickadees were color-banded as nestlings. After fledging, the birds remained with their parents on or near the parental territory for about 3 weeks. In late June or early July family breakup occurred suddenly, with the young moving rapidly away. Most of the birds disappeared completely from the area; 6 were later discovered in the breeding population at distances of 0.4 to ca. 11 km, with a median dispersal distance of 1.1 km. This movement appeared to be an innate dispersal mechanism. In contrast, among 103 chickadees first trapped in July and early August as independent juveniles and later found on their breeding territories, the median distance from point where banded to territory was 204 m (maximum = 1,160 m). As distances up to 2.4 km could have been detected in our study area, we conclude that by late July and August chickadees have virtually finished dispersing and are developing site tenacity in the places where they will subsequently breed. Whether dispersal also occurs in spring was investigated using the monthly patterns of arrivals and disappearances from winter feeders. Adults and summer-banded juveniles inhabiting the parts of the study area nearest the feeders arrived for the first time at the feeders in November and December, but birds from more remote areas continued to arrive through the winter and spring. In previously unbanded juveniles there was an increase in arrivals in March and April. On the basis of an analysis of loss rates by sex and age, we conclude that only about 5% of yearling males and 9% of yearling females undertake some dispersal or spacing movements in spring. Thus, in the Black-capped Chickadee the main dispersal mechanism is an innate, rapid, fairly long-distance movement of the juvenile, taking place in summer just after family breakup. A small fraction of the yearling population undertakes some dispersal movement in the winter or spring.
Relative Heart Size in Alaskan Tetraonidae
Authors: Weeden Robert B. 
Published: July 2020

Abstract
Heart:body size ratios were measured in over 1,900 specimens of seven species of Alaskan Tetraonidae. Blue Grouse (Dendragapus obscurus) and Ruffed Grouse (Bonasa umbellus) have hearts averaging only 0.4 to 0.5% of body weight. At the other extreme, Rock Ptarmigan (Lagopus mutus) have hearts averaging 2.0% of body weight. Between these extremes are White-tailed Ptarmigan (L. leucurus), 1.1%; Spruce Grouse (Canachites canadensis), 1.2%; Sharp-tailed Grouse (Pedioecetes phasianellus), 1.4%; and Willow Ptarmigan (L. lagopus), 1.4%. Intraspecific variations related to sex, age, body size, season, and locality were found in some but not all species. The members of this family seem to have evolved diverse strategies for meeting cardiovascular requirements, and heart size alone does not reveal the nature of these systems.
Male Characteristics and Pairing Success in Red-Winged Blackbirds
Authors: Searcy William A. 
Published: July 2020

Abstract
As female Red-winged Blackbirds (Agelaius phoeniceus) in Washington populations choose mates mainly on the basis of territory quality, sexual selection should favor those characteristics that enhance a male redwing's ability to obtain and defend a good territory. In this study, correlations were sought between harem size and characteristics of male redwings that might be expected to contribute to the ability to compete for territory. Weak evidence is presented that large size, experience, good physiological condition, and the ability to devote a large proportion of daily activity to territory defense contribute to pairing success in some years. Even the significant correlations between success and male characteristics are weak, but strong correlations cannot be expected because (1) many different male characteristics probably contribute to competitive ability, none of which are of overwhelming importance; (2) males will not always make the optimal choice of territory, especially as their choice is constrained by extreme site fidelity; and (3) females will also fail to make optimal choices of territories and mates.
Rainfall on the Galápagos and the Demography of Darwin’s Finches
Authors: Grant Peter R. , Boag Peter T. 
Published: July 2020

Abstract
Monthly rainfall has been registered at eight sites on four of the Galápagos Islands for a variable number of years. The most extensive, continuous records are from a coastal site on San Cristóbal for the period 1950-67. Analysis of all these data establish the following characteristics: (1) Although rainfall is seasonal, it is very variable, particularly in the wet-season months of January to May. (2) Annual variation is very large. The amount of rainfall tends to alternate in successive years, and a 4-yr periodicity in rainfall is indicated. (3) There is also variation on a longer time scale; the 1950's were 50% wetter than the 1960's. (4) There is more precipitation per year at high elevations than at low elevations, it is distributed more evenly throughout the year, and it varies less among years. Finch demography, particularly reproductive aspects, is suggested to be influenced by rainfall through the effect of rainfall upon food supply. Several qualitative predictions about reproduction, mortality, and dispersal are made on the basis of the established patterns of variation in rainfall. The meagre data on finch population dynamics are consistent with these predictions, but future research is required to test them adequately.