bluuebunny/crossref_metadata_2025 huggingface dataset:
Great apes use self-experience to anticipate an agent’s action in a false-belief test
Authors: Kano Fumihiro , Krupenye Christopher , Hirata Satoshi , Tomonaga Masaki , Call Josep
Published: October 2019

Significance

Many unique features of human communication, cooperation, and culture depend on theory of mind, the ability to attribute mental states to oneself and others. But is theory of mind uniquely human? Nonhuman animals, such as humans’ closest ape relatives, have succeeded in some theory-of-mind tasks; however, it remains disputed whether they do so by reading others’ minds or their behavior. Here, we challenged this behavior-rule account using a version of the goggles test, incorporated into an established anticipatory-looking false-belief task with apes. We provide evidence that, in the absence of behavioral cues, apes consulted their own past experience of seeing or not seeing through a novel barrier to determine whether an agent could see through the same barrier.
An experimental test of the ovulatory homolog model of female orgasm
Authors: Pavlicev Mihaela , Zupan Andreja Moset , Barry Amanda , Walters Savannah , Milano Kristin M. , Kliman Harvey J. , Wagner Günter P.
Published: October 2019

Significance

The existence of female orgasm is intriguing for 2 reasons: On the one hand, female orgasm is not necessary for female reproductive success, and on the other hand, this neuro-endocrine reflex is too complex to be an evolutionary accident. This led to many proposed evolutionary explanations, most of which have little empirical support. We previously proposed that female orgasm uses a mechanism that originated for inducing ovulation during copulation: A mechanism that still exists in many animals but lost its role in others. Here we provide experimental evidence, strengthening the likelihood that female orgasm evolved from copulation-induced ovulation. This finding helps interpreting otherwise difficult to explain aspects of female sexuality, such as the low rate of female orgasm during intercourse.
X
chromosome and autosomal recombination are differentially sensitive to disruptions in SC maintenance
Authors: Billmyre Katherine Kretovich , Cahoon Cori K. , Heenan G. Matthew , Wesley Emily R. , Yu Zulin , Unruh Jay R. , Takeo Satomi , Hawley R. Scott
Published: October 2019

The synaptonemal complex (SC) is a conserved meiotic structure that regulates the repair of double-strand breaks (DSBs) into crossovers or gene conversions. The removal of any central-region SC component, such as the
Drosophila melanogaster
transverse filament protein C(3)G, causes a complete loss of SC structure and crossovers. To better understand the role of the SC in meiosis, we used CRISPR/Cas9 to construct 3 in-frame deletions within the predicted coiled-coil region of the C(3)G protein. Since these 3 deletion mutations disrupt SC maintenance at different times during pachytene and exhibit distinct defects in key meiotic processes, they allow us to define the stages of pachytene when the SC is necessary for homolog pairing and recombination during pachytene. Our studies demonstrate that the
X
chromosome and the autosomes display substantially different defects in pairing and recombination when SC structure is disrupted, suggesting that the
X
chromosome is potentially regulated differently from the autosomes.
Theory and simulations for RNA folding in mixtures of monovalent and divalent cations
Authors: Nguyen Hung T. , Hori Naoto , Thirumalai D.
Published: October 2019

Significance

RNA molecules require ions to fold. The problem of how ions of differing sizes and valences drive the folding of RNA molecules is unsolved. Here, we take a major step in its solution by creating a method, based on the theory of polyatomic liquids, to calculate the potential between divalent ions and the phosphate groups. The resulting model, accounting for inner and outer sphere coordination of Mg
2+
and Ca
2+
to phosphates, when used in coarse-grained molecular simulations, predicts folding free energies for a number of RNA molecules in the presence of both divalent and monovalent ions that are in excellent agreement with experiments. This work sets the stage for probing sequence and ion effects on DNA and synthetic polyelectrolytes.
Investigation of WC–Co alloy properties based on thermodynamic calculation and Weibull distribution
Authors: Tian Haixia , Chen Jun , Zhu Gensong , Du Yong , Peng Yingbiao
Published: October 2019

The influence of alloy composition and sintering temperature on the mechanical properties and reliability of WC–Co cemented carbides was studied theoretically and experimentally. For the first time, through a hybrid approach of thermodynamic calculations and Weibull distribution, the comprehensive performance of ultrafine WC–Co cemented carbides with different C contents and inhibitor type was investigated in detail. The carbon content of WC–10 wt-% Co–0.5 wt-% Cr cemented carbides was carefully controlled within the range of 5.38−5.52 wt-%. The contents of Cr and V are chosen to be in the range of 0–1 wt-%. It is found that WC–10 wt-% Co–0.5 wt-% Cr alloys with 5.46 wt-% C or 5.5 wt-% C show excellent mechanical properties and high reliability. WC–10 wt-% Co alloys with 0.5 wt-% Cr and 0.4 wt-% Cr–0.2 wt-% V demonstrate high mechanical property and reliability. The results of this study can be used to design process parameters during the manufacture of WC–Co cemented carbides.
Isolation methods of high glycosidase-producing mutants of Aspergillus luchuensis and its mutated genes
Authors: Tomimoto Kazuya , Osafune Yukio , Kakizono Dararat , Han Jinshun , Mukai Nobuhiko
Published: October 2019

High glycosidase-producing strains of Aspergillus luchuensis were isolated from 2-deoxyglucose (2-DG) resistant mutants. α-Amylase, exo-α-1,4-glucosidase, β-glucosidase and β-xylosidase activity in the mutants was ~3, ~2, ~4 and ~2.5 times higher than the parental strain RIB2604 on koji-making conditions, respectively. Citric acid production and mycelia growth of the mutants, however, approximately halved to that of the parent. Compared to the parent, the alcohol yield from rice and sweet potato shochu mash of the mutant increased ~5.7% and 3.0%, respectively. The mutant strains showed significantly low glucose assimilability despite the fructose one was almost normal, and they had a single missense or nonsense mutation in the glucokinase gene glkA. The recombinant strain that was introduced at one of the mutations, glkA Q300K, demonstrated similar but not identical phenotypes to the mutant strain. This result indicates that glkA Q300K is one of the major mutations in 2-DG resistant strains.
Influences: Short circuits
Authors: Clapham David E.
Published: October 2019

Clapham recalls his early adventures with Lou DeFelice and Erwin Neher.
Trapping of C2
− in a digital ion trap
Authors: Hinterberger Alexander , Gerber Sebastian , Oswald Emanuel , Zimmer Christan , Fesel Julian , Doser Michael
Published: October 2019

In this article we present the production of a pulsed molecular C2
− beam and the subsequent trapping of C2
− in a digital ion trap (DIT). The anionic molecules were produced in a pulsed discharge valve from acetylene and carbon dioxide gas in a helium carrier. The mass spectrum of the pulsed anion beam is initially recorded using a Wien filter. Subsequently, we measured the mass spectrum using the DIT and its stability diagram. The results are compared to a theoretical description of the trap’s stability conditions. The research is relevant for future laser cooling experiments of trapped C2
− and for sympathetic cooling experiments of other anionic species (antiprotons, electrons, anionic atoms and molecules) and are of interest for precision experiments on antihydrogen as performed at the antiproton decelerator facility at CERN.
Manipulating birefringence in AgCl thin film loaded by silver nanoparticles under normal and oblique incident angles
Authors: Jazi Shadi Safaei , Talebi Razieh
Published: October 2019

We have induced anisotropy in AgCl thin film, which is loaded by silver nanoparticles, by irradiating a single low power laser beam at wavelength 532 nm. The induced anisotropy in Ag–AgCl thin film is due to the formation of gratings in the direction of light polarization for both normal and oblique angles of laser incidence. In Ag–AgCl thin film, which was irradiated by oblique laser beam, complex grating with different line-spaces is formed. It turns out that the line-spaces of the grating depend on the incident angle. Therefore, by changing the incident angle of the laser beam, the morphology and optical properties of anisotropic nanostructures formed on Ag–AgCl thin film can be manipulated. Linear birefringence and linear dichroism are measured in these nanostructures by probe beams at different wavelengths in the visible region. Our results show that the sample which is irradiated normally has the largest linear birefringence and linear dichroism compared to the oblique incident samples. In the normal incident sample, the maximum value of linear birefringence is seen at wavelength 632.8 nm (Δn  =  0.35), while the largest absolute value of linear dichroism is observed at wavelength 532 nm, which is the same wavelength as the incident laser beam.
A compact system for intraoperative specimen imaging based on edge illumination x-ray phase contrast
Authors: Havariyoun Glafkos , Vittoria Fabio A , Hagen Charlotte K , Basta Dario , Kallon Gibril K , Endrizzi Marco , Massimi Lorenzo , Munro Peter , Hawker Sam , Smit Bennie , Astolfo Alberto , Larkin Oliver J , Waltham Richard M , Shah Zoheb , Duffy Stephen W , Nelan Rachel L , Peel Anthony , Suaris Tamara , Jones J Louise , Haig Ian G , Bate David , Olivo Alessandro
Published: October 2019

A significant number of patients receiving breast-conserving surgery (BCS) for invasive carcinoma and ductal carcinoma in situ (DCIS) may need reoperation following tumor-positive margins from final histopathology tests. All current intraoperative margin assessment modalities have specific limitations. As a first step towards the development of a compact system for intraoperative specimen imaging based on edge illumination x-ray phase contrast, we prove that the system’s dimensions can be reduced without affecting imaging performance.

We analysed the variation in noise and contrast to noise ratio (CNR) with decreasing system length using the edge illumination x-ray phase contrast imaging setup. Two-(planar) and three-(computed tomography (CT)) dimensional imaging acquisitions of custom phantoms and a breast tissue specimen were made. Dedicated phase retrieval algorithms were used to separate refraction and absorption signals. A ‘single-shot’ retrieval method was also used, to retrieve thickness map images, due to its simple acquisition procedure and reduced acquisition times. Experimental results were compared to numerical simulations where appropriate.

The relative contribution of dark noise signal in integrating detectors is significant for low photon count statistics acquisitions. Under constant exposure factors and magnification, a more compact system provides an increase in CNR. Superior CNR results were obtained for refraction and thickness map images when compared to absorption images. Results indicate that the ‘single-shot’ acquisition method is preferable for a compact CT intraoperative specimen scanner; it allows for shorter acquisition times and its combination of the absorption and refraction signals ultimately leads to a higher contrast. The first CT images of a breast specimen acquired with the compact system provided promising results when compared to those of the longer length system.
Thermal spin photonics in the near-field of nonreciprocal media
Authors: Khandekar Chinmay , Jacob Zubin
Published: October 2019

The interplay of spin angular momentum and thermal radiation is a frontier area of interest to nanophotonics as well as topological physics. Here, we show that a thick planar slab of a nonreciprocal material, despite being at thermal equilibrium with its environment, can exhibit nonzero photon spin angular momentum and nonzero radiative heat flux in its vicinity. We identify them as the persistent thermal photon spin and the persistent planar heat current respectively. With a practical example system, we reveal that the fundamental origin of these phenomena is connected to the spin-momentum locking of thermally excited evanescent waves. We also discover spin magnetic moment of surface polaritons that further clarifies these features. We then propose an imaging experiment based on Brownian motion that allows one to witness these surprising features by directly looking at them using a lab microscope. We further demonstrate the universal behavior of these near-field thermal radiation phenomena through a comprehensive analysis of gyroelectric, gyromagnetic and magneto-electric nonreciprocal materials. Together, these results expose a surprisingly little explored research area of thermal spin photonics with prospects for new avenues related to non-Hermitian topological photonics and radiative heat transport.
Silicon-doped indium oxide – a promising amorphous oxide semiconductor material for thin-film transistor fabricated by spin coating method
Authors: Hoang Ha , Sasaki Kazutaka , Hori Tatsuki , Tsukagoshi Kazuhito , Nabatame Toshihide , Quoc Trinh Bui Nguyen , Fujiwara Akihiko
Published: October 2019

Silicon-doped indium oxide (In-Si-O or ISO) has been investigated as the channel material of thin-film transistor (TFT) for the application of next generation flat panel displays. Because solution processing is simple, low cost and low power consumption in comparison with physical vapour deposition, it is a potential candidate for TFTs fabrication. We have been exploring research on TFT using ISO system via spin coating method. In this work, the performance of 3 at.% Si-doped indium oxide TFT has been improved with the highest mobility of 3.8 cm2/Vs without the passivation layer.
Mechanical strength of natural rubber filled fly ash
Authors: Dasaesamoh A , Osotchan T , Subannajui K
Published: October 2019

In this present work, Fly ash was incorporated into natural rubber to form a natural rubber composite. The natural rubber composite was prepared by solution mixing method at the constant amount of fly ash at 80 phr. The fly ash particle was modified its surface by TESPT silane coupling agent before mixing with natural rubber latex. The surface morphology of natural rubber composites were examined by SEM image. The vulcanization parameters were examined by MDR technique. The results show that modified fly ash affects to natural rubber compound by shorten the vulcanization time and increase maximum torque. The mechanical properties were investigated from stress-strain curve. It reveals that the surface modification of fly ash improves tensile strength of natural rubber by 6 times. The increasing of strength may attribute to the formation of polymer-fillers interaction through TESPT molecules.
Electrochemical determination of diethylstilbestrol by using a magnetic nanoparticle/graphene composite film electrode
Authors: Poo-arporn Yingyot , Pakapongpan Saithip , Poo-arporn Rungtiva P.
Published: October 2019

The magnetic nanoparticle-graphene modified magnetic carbon electrode (MCE) was fabricated and the electrochemical effect of diethylstilbestrol (DES) on this electrode was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The factors that affected the performance of the sensor were also optimized. The experimental results exhibited good electrocatalytic activity and a fast response for the electrochemical oxidation of DES. The linear range for the determination of diethylstilbestrol was 1 to 100 μM and the detection limits were 1.06 × 10−7 M based on S/N = 3.
Oxalate precipitation synthesis of copper-manganese nanoparticles for methanol steam reforming
Authors: Edañol Y D G , Barbosa R L , Buenviaje S C , Payawan L M
Published: October 2019

CuMn spinel nanoparticles were prepared using the oxalate precipitation synthesis technique using nitrate salts as precursors. The samples were characterized using X-ray diffractometry (XRD), and field emission – scanning electron microscopy (FE-SEM). The mixed oxalate precursor, CuMn*C2O4, was found to be single-phase and crystalline compound. H2-assisted temperature-programmed decomposition of the mixed oxalates yielded Cu1.5Mn1.5O4 spinel nanoparticles with CuO present in very minute amounts. FE-SEM analysis of the Cu1.5Mn1.5O4 spinel showed a spherical morphology of the nanoparticles. The average size of the Cu1.5Mn1.5O4 spinel nanoparticles was 11.512 nm. Thus, the nano-sized Cu1.5Mn1.5O4 spinel nanoparticles can be used as catalysts for the methanol steam reforming (MSR) reaction.
Photo-oxidation of an organosulfur for photo-charging of lithium-ion batteries
Authors: Shingu Hiroyuki , Uemachi Hiroshi , Fujiwara Akihiko
Published: October 2019

Polymers of organosulfur with S-S bonds are potential cathode materials for high-capacity lithium-ion batteries, and the photo-oxidation of organosulfurs can be applied in the future to the photo-charging of batteries. Herein, we present the photo-oxidation of dithiobiuret (DTB), a simple organosulfur molecule with two neighbouring tautomeric thiol/thione groups (-SH/>C=S) that can form a disulfide (S-S) bond by reversible intramolecular oxidative cyclization. Aqueous solutions of DTB with different pH values were irradiated by visible light from a halogen lamp. Photo-oxidation was confirmed by ultraviolet (UV) absorption spectroscopy, on comparison of the UV absorption spectra of DTB and chemically oxidized DTB. The rate of photo-oxidation depended on the pH of the DTB solution, and the highest photo-oxidation rate of ∼ 2.8 × 10−3 min.−1 was observed at a pH of ∼ 3.1.
Thyroid Incidentalomas in Association With Low-Dose Computed Tomography in the National Lung Screening Trial
Authors: Loomans-Kropp Holli A , Dunn Barbara K , Kramer Barnett S , Pinsky Paul
Published: October 2019

Advances in cancer screening methods have opened avenues for incidental findings and cancer overdiagnosis. We performed a secondary analysis of the National Lung Screening Trial (enrollment from 2002–2004), a randomized controlled trial comparing low-dose computed tomography (LDCT; n = 26,722) with chest radiography (CXR; n = 26,732) for lung cancer detection, to examine incidental findings related to thyroid cancer (ThCa). Three screening rounds were included, and median follow-up was 6.6 years for LDCT and 6.5 years for CXR. Radiologists reported lung and non-lung-related abnormalities. In the LDCT arm, 5.7%, 4.7%, and 4.5% of participants had abnormalities above the diaphragm (AADs) detected at baseline, year 1, and year 2, respectively, compared with 2.3%, 1.5%, and 1.3% in the CXR arm. In the LDCT arm, 205 AADs (7.0%) were thyroid-related. Overall, 60 ThCas were reported, 35 in the LDCT arm and 25 in the CXR arm (P = 0.2). In the LDCT arm, participants with a prior AAD had a 7.8-fold increased risk (95% confidence interval: 4.0, 15.1) of ThCa compared with those who did not have an AAD. Early and persistent excess of ThCas diagnosed earlier in the LDCT arm suggests overdiagnosis. The use of sensitive screening modalities for early detection of lung cancer might result in the discovery of thyroid incidentalomas.
Incidence of Initial Renal Replacement Therapy Over the Course of Kidney Disease in Children
Authors: Ng Derek K , Matheson Matthew B , Warady Bradley A , Mendley Susan R , Furth Susan L , Muñoz Alvaro
Published: October 2019

The Chronic Kidney Disease in Children Study, a prospective cohort study with data collected from 2003 to 2018, provided the first opportunity to characterize the incidence of renal replacement therapy (RRT) initiation over the life course of pediatric kidney diseases. In the current analysis, parametric generalized gamma models were fitted and extrapolated for RRT overall and by specific treatment modality (dialysis or preemptive kidney transplant). Children were stratified by type of diagnosis: nonglomerular (mostly congenital; n = 650), glomerular–hemolytic uremic syndrome (HUS; n = 49), or glomerular–non-HUS (heterogeneous childhood onset; n = 216). Estimated durations of time to RRT after disease onset for 99% of the nonglomerular and glomerular–non-HUS groups were 42.5 years (95% confidence interval (CI): 31.0, 54.1) and 25.4 years (95% CI: 14.9, 36.0), respectively. Since onset for the great majority of children in the nonglomerular group was congenital, disease duration equated with age. A simulation-based estimate of age at RRT for 99% of the glomerular population was 37.9 years (95% CI: 33.6, 63.2). These models performed well in cross-validation. Children with glomerular disease received dialysis earlier and were less likely to have a preemptive kidney transplant, while the timing and proportions of dialysis and transplantation were similar for the nonglomerular group. These diagnosis-specific estimates provide insight into patient-centered prognostic information and can assist in RRT planning efforts for children with moderate-to-severe kidney disease who are receiving regular specialty care.
State School Policies as Predictors of Physical and Mental Health: A Natural Experiment in the REGARDS Cohort
Authors: Brenowitz Willa D , Manly Jennifer J , Murchland Audrey R , Nguyen Thu T , Liu Sze Y , Glymour M Maria , Levine Deborah A , Crowe Michael , Hohman Timothy J , Dufouil Carole , Launer Lenore J , Hedden Trey , Eng Chloe W , Wadley Virginia G , Howard Virginia J
Published: October 2019

We used differences in state school policies as natural experiments to evaluate the joint influence of educational quantity and quality on late-life physical and mental health. Using US Census microsample data, historical measures of state compulsory schooling and school quality (term length, student-teacher ratio, and attendance rates) were combined via regression modeling on a scale corresponding to years of education (policy-predicted years of education (PPYEd)). PPYEd values were linked to individual-level records for 8,920 black and 14,605 white participants aged ≥45 years in the Reasons for Geographic and Racial Differences in Stroke study (2003–2007). Linear and quantile regression models estimated the association between PPYEd and Physical Component Summary (PCS) and Mental Component Summary (MCS) from the Short Form Health Survey. We examined interactions by race and adjusted for sex, birth year, state of residence at age 6 years, and year of study enrollment. Higher PPYEd was associated with better median PCS (β = 1.28, 95% confidence interval (CI): 0.40, 1.49) and possibly better median MCS (β = 0.46, 95% CI: –0.01, 0.94). Effect estimates were higher among black (vs. white) persons (PCS × race interaction, β = 0.22, 95% CI: –0.62, 1.05, and MCS × race interaction, β = 0.18; 95% CI: –0.08, 0.44). When incorporating both school quality and duration, this quasiexperimental analysis found mixed evidence for a causal effect of education on health decades later.
The Association Between Body Mass Index and Pancreatic Cancer: Variation by Age at Body Mass Index Assessment
Authors: Jacobs Eric J , Newton Christina C , Patel Alpa V , Stevens Victoria L , Islami Farhad , Flanders W Dana , Gapstur Susan M
Published: October 2019

Higher body mass index (BMI; weight (kg)/height (m)2) is associated with increased risk of pancreatic cancer in epidemiologic studies. However, BMI has usually been assessed at older ages, potentially underestimating the full impact of excess weight. We examined the association between BMI and pancreatic cancer mortality among 963,317 adults who were aged 30–89 years at their enrollment in Cancer Prevention Study II in 1982. During follow-up through 2014, a total of 8,354 participants died of pancreatic cancer. Hazard ratios per 5 BMI units, calculated using proportional hazards regression, declined steadily with age at BMI assessment, from 1.25 (95% confidence interval: 1.18, 1.33) in persons aged 30–49 years at enrollment to 1.13 (95% confidence interval: 1.02, 1.26) in those aged 70–89 years at enrollment (P for trend = 0.005). On the basis of a hazard ratio of 1.25 per 5 BMI units at age 45 years, we estimated that 28% of US pancreatic cancer deaths among persons born in 1970–1974 will be attributable to BMI ≥25.0—nearly twice the equivalent proportion of those born in the 1930s, a birth cohort with much lower BMI in middle age. These results suggest that BMI before age 50 years is more strongly associated with pancreatic cancer risk than BMI at older ages, and they underscore the importance of avoiding excess weight gain before middle age for preventing this highly fatal cancer.
Gluteal Vein Anatomy: Location, Caliber, Impact of Patient Positioning, and Implications for Fat Grafting
Authors: Turin Sergey Y , Fracol Megan , Keller Eric , Markl Michael , Collins Jeremy , Krochmal Daniel , Kim John Y S
Published: October 2019

Background

Deaths in gluteal autografting occur due to gluteal vein injuries, but data are lacking on the precise location and caliber of these veins.

Objectives

The authors sought to present the first in vivo study of gluteal vein anatomy utilizing magnetic resonance imaging.

Methods

Magnetic resonance imaging venography of 16 volunteer hemi-sections was conducted in the supine, prone, prone with a bump (jack-knife), and left and right decubitus positions in 1 session after a single contrast administration. Caliber and course of the superior and inferior gluteal veins (SGV/IGV) were analyzed vs bony landmarks and position changes.

Results

The SGV has a very short submuscular course before splitting into 2 smaller branches superolaterally. The IGV runs immediately deep to the gluteus maximus in the center of the buttock as a single large trunk, on average 56 mm deep (mean 27 mm of muscle belly and 30 mm subcutaneous fat). No intramuscular or subcutaneous branches greater than 2 mm were found. In the prone position, the IGV and SGV have an average caliber of 5.96 mm and 5.63 mm. Vessel caliber decreased by 21% and 27%, respectively, in the jack-knife position and by 14% and 15% in lateral decubitus.

Conclusions

The SGV and IGV are immediately deep to gluteus maximus approximately 6 cm deep with a caliber on the order of 6 mm in the prone position. The distribution of these vessels suggests there is no “safe zone” in the intramuscular or submuscular planes. The jackknife or lateral decubitus positions can decrease vein caliber by up to 27%, possibly reducing the risk of injury due to either traction or direct cannula impact.
Time and Energy Budgets of the Mockingbird (Mimus polyglottos) during the Breeding Season
Authors: Biedenweg Douglas W.
Published: October 2019

A time and energy budget of male and female Mockingbirds (Mimus polyglottos) in six phases of their breeding cycle was completed using the equivalent temperature model to predict perching metabolic rates. Recorded time-budget behaviors included perching, bipedal locomotion, flight, and the time spent in the sun and shade. Over the total study period, males and females spent an average of 92.3% and 92.8% of their active day perched, 2.4% and 1.6% in bipedal locomotion, and 5.3% and 5.6% in flight, respectively. BMR plus thermostatic requirements averaged, seasonally, 78.1% of DEEtot in males and 76.1% in females. The choice of shaded or exposed microhabitats made very little difference in energy expenditure. DEEtot varied from 96.9 kJ in males with incubating females to 113.0 kJ in males caring for fledglings, and from 75.1 kJ in incubating females to 113.2 kJ in females caring for fledglings. Unmated, pre-nest-building, and incubating birds spent significantly less energy than did birds caring for nestlings (P < 0.05) or birds caring for fledglings (P < 0.05). With the exception of the nest-building phase, when females are producing eggs, and the incubation phase, when females gain insulation from the nest, male and female DEEtot closely paralleled each other throughout the season. The large amount of predation that occurred at the study site suggests that birds may allocate time to perching to minimize the probability of predation on themselves or their offspring.
Hunting Behavior, Prey Selection, and Energetics of Snail Kites in Guyana: Consumer Choice by a Specialist
Authors: Beissinger Steven R.
Published: October 2019

The hunting behavior, snail size selection, and time-activity patterns of non-breeding Snail Kites (Rostrhamus sociabilis sociabilis) were studied in Guyana rice fields. Kites spent 62% of the photoperiod perching, 19% foraging, 13% in maintenance activities, and 6% flying. As the day progressed, the percentage of daylight hours spent perching increased significantly, while foraging decreased significantly. Kites successfully captured and ingested Pomacea snails in 78% of the foraging bouts observed. The mode of hunting was evenly split between coursing (50.7%) and still-hunting (49.3%). Searching and returning times were related to time of day, as significantly more coursing hunts and still-hunts occurred in mornings and late afternoons, respectively. Prey handling time was the most time-consuming component of a foraging bout. Time spent searching for prey, returning, or handling prey was not related to snail size. The size distribution of captured snails differed significantly from that of available snails; kites selected more medium snails and fewer small snails and took large snails in equal frequency to that at which large snails were available. Kites captured the same-sized snails when coursing as when still-hunting. As rice grew, kite utilization of rice fields declined, and the frequency of still-hunting decreased while course-hunting attempts increased. The daily caloric intake of kites was estimated to be 104.2 kcal, the daily energy expenditure 85.7 kcal. Results are discussed in relation to consumer choices of specialists. The most important decision a foraging Snail Kite may make is what patch to search in and how long to search before abandoning patches.
Communication with Shared Song Themes in Tufted Titmice
Authors: Schroeder Donna J. , Wiley R. Haven
Published: October 2019

Individual Tufted Titmice (Parus bicolor) sing 8-12 song themes. Most or all themes in an individual's repertoire are shared with neighbors, although slight but consistent differences often separate neighbors' performances of a particular theme. Birds first begin to sing recognizable themes while still juveniles on their parents' territory. Established territorial residents can modify their themes slightly from year to year to achieve a closer similarity to neighbors' themes. Neighbors matched themes during concurrent singing more often than would be expected at random. Furthermore, titmouse tended to begin singing in response to a neighbor, particularly if it could match the theme. Playbacks of recorded song also evoked matched singing in response. Playbacks of strangers' songs, recorded 3 km away, evoked a less intense response than did playbacks of neighbor's songs, but an attempt to demonstrate individual recognition of a neighbor's shared themes failed. Evidently, the advantages of coordinated singing by opponents with shared themes outweigh any advantages of individual recognition of neighbors with distinctive songs.
Brood Reduction in Black-Legged Kittiwakes
Authors: Braun Barbara M. , Hunt George L.
Published: October 2019

In 1978 and 1979 we studied brood reduction in Black-legged Kittiwakes (Rissa tridactyla) on St. Paul Island, Alaska. In two-egg clutches, first-laid eggs were largest; they were incubated before second eggs were laid and consequently hatched first. Chicks from first-laid eggs begged more frequently, fed more frequently, grew faster, and were more aggressive than their sibs. These sibling differences frequently facilitated the ejection of younger siblings from the nest by first-hatched young. Lower feeding and growth rates and higher aggression levels occurred in broods in which the second chicks subsequently died than in broods in which both chicks fledged. Chick loss was most frequent during inclement weather. These data are consistent with the hypothesis that brood reduction is related to the amount of food that chicks receive.
Aspects of Food Finding by Wintering Bald Eagles
Authors: Knight Susan K. , Knight Richard L.
Published: October 2019

We examined three aspects of food location by Bald Eagles (Haliaeetus leucocephalus) wintering along the Nooksack River, Washington. First, eagles used intra- and interspecific local enhancement to locate food. Second, the time that eagles spent aerially searching for food, as indicated by the percentage of eagles flying or soaring, was negatively correlated with relative food availability. Third, eagles often followed others when departing from or arriving at communal night roosts. Following was most frequent when all food was eliminated by flood waters, suggesting a possible food-location function of this behavior. During the flood period, adult eagles were followed more often than immatures.
The Pattern of Migration of Village Weaverbirds (Ploceus cucullatus) in Southwestern Nigeria
Authors: Adegoke A. S.
Published: October 2019

I investigated the migration of Village Weaverbirds (Ploceus cucullatus) in southwestern Nigeria in order to determine the sources of birds causing crop damage. I observed banded adult, juvenile, and nestling weaverbirds at their colonies, roosts, and feeding grounds. Over a 21-month period, 6 birds were recaptured at the point of ringing and another 6 at a maximum distance of 1.5 km from the point of ringing. This and other observations indicate that Village Weaverbirds do not undertake long-distance migrations and that local bird populations cause the damage to local crops. Some Village Weaverbirds roost on shrubs and grasses throughout the year, some breed and sleep in colonies in villages from January to early August and from October to early December, and some roost in tall trees near human dwellings from late December to April. The birds roosting on shrubs and grasses are more accessible than the birds roosting in tall trees, and their elimination would provide a more effective means of control than does the present method of scaring the birds from a particular area.
The Reaction of Great Tits (Parus major) to Playback of Degraded and Undegraded Songs: The Effect of Familiarity with the Stimulus Song Type
Authors: McGregor Peter K. , Krebs John R. , Ratcliffe Laurene M.
Published: October 2019

We played degraded and undegraded song types to territorial Great Tits. Each bird was tested with degraded and undegraded renditions of a song type in its repertoire and of a song not in its repertoire. The birds responded less strongly to degraded than to undegraded songs, and the difference was significant only if the test song was of the same type as, or similar to, one in the bird's repertoire. These results are consistent with Richards' (1981) hypothesis that degradation cues are used to judge distance and Morton's (1982) idea that degradation may be judged by comparison with a standard consisting of the bird's own rendition of the song. We also found that birds are better able to discriminate between undegraded and degraded song types if their neighbors sing the song. The results are discussed in relation to hypotheses concerning song matching and neighbor-stranger discrimination.
A Complex Call of the Black-Capped Chickadee (Parus atricapillus). I. Microgeographic Variation
Authors: Ficken Millicent S. , Weise Charles M.
Published: October 2019

We studied the syllabic structure of the Gargle, a complex vocalization of the Black-capped Chickadee that is often associated with agression, at three main sites in southeastern Wisconsin, at one site over an 11-yr period. Sites as close as 5.7 km showed major differences in syllables, and birds at some sites differed somewhat in the number of syllables per call. Each individual probably uses all the syllables (16-23 different ones) occurring at a particular site. The syllables occurring at the end of the vocalization were shared among different demes, while the introductory syllables were usually different. Syllables showed relatively little change with time. Dialects apparently correspond to demes in this species. The syllables are arranged in many combinations and permutations to generate a large variety of Gargle types, most of which are very rare. A few Gargle types are more common ("universals") and are usually confined to a particular site. Such a complex dialect pattern is unusual in a call.
Differences in Repertoire Size, Singing Behavior, and Associated Neuroanatomy Among Marsh Wren Populations Have a Genetic Basis
Authors: Kroodsma Donald E. , Canady Richard A.
Published: October 2019

Among songbirds, adult song forms usually are determined culturally during an individual's early experience. In the Marsh Wren (Cistothorus palustris), we have demonstrated that the quantity of this learned behavior (i.e. song repertoire size), its style of delivery, and the size of controlling nuclei in the forebrain have a genetic basis. Nestling males taken from New York and California and reared under standardized conditions in the laboratory still develop population-typical behavior and neuroanatomy. We do not know the developmental mechanisms responsible for these differences, but we believe that year-round residency, high densities, and polygynous mating systems are likely factors contributing to an escalation of vocal abilities in the western populations.
Hybridization, Introgression, and Morphometric Differentiation between Mallard (Anas platyrhynchos) and Grey Duck (Anas superciliosa) in Otago, New Zealand
Authors: Gillespie Grant D.
Published: October 2019

Small numbers of Mallard (Anas platyrhynchos) were introduced into New Zealand from Great Britain and North America over 100 years ago. Both sexes have undergone differentiation in size and plumage characters as a consequence of hybridization with the indigenous Grey Duck (A. superciliosa). Pure forms of both species, as documented by early descriptions, appear to be disappearing, particularly the Grey Duck. In Otago, the Mallard and Grey Duck are introgressively hybridizing, and the majority of intergrades are Mallard-like in appearance. Separation of Mallards, hybrid birds, and Grey Ducks was achieved using a stepwise cluster analysis of mensural characters. The observed morphometric differentiation was not continuous throughout the Otago population, and a total of 5 discontinuities (groups of morphologically similar birds) were distinguished: male Mallards, female Mallards, Grey Ducks, and 2 groups of hybrid birds. The use of bivariate scattergrams of skull length and eye-lens weight provided the most useful illustration of the distinctions among Mallard, hybrid, and Grey Duck populations. As a consequence of hybridization, two morphologically distinct hybrid populations have been produced: one resembles the Grey Duck and the other the Mallard. This situation is discussed in relation to the two hybrid forms of the Marianas Mallard (A. oustaleti).

The Mallard was so successful in newly created agricultural habitat that by 1958 this species constituted 53% of the Mallard-Grey Duck population. Prior to 1958 the observed hybrid frequency was less than 3% and the reduction in the proportion of the Grey Duck most probably was the result of habitat reduction. In 1977 the Mallard comprised 82% of the Mallard-Grey Duck population, and there was concern over the number of pure Grey Ducks remaining in Otago. By 1981-1982 levels of hybridization, based on plumage analysis, had reached 51%, and the proportion of pure Grey Ducks had dropped to 4.5%, which is below the level suggested for the maintenance of a species. In the absence of reproductive isolation or antihybridization mechanisms between these two species, the Mallard and hybrid populations represent a potential threat to the conservation of the New Zealand Grey Duck.
The Phylogeny of the Alcidae
Authors: Strauch J. G.
Published: October 2019

An estimate of the phylogeny of 22 extant and 1 extinct species of the Alcidae was determined from compatibility analyses of 33 cladistic characters of the skeleton, integument, and natural history. The puffins were found to be a sister-group to all other alcids. Cerorhinca was found to be a puffin. The auklets were found to be a sister-group to the remaining species. Brachyramphus was found to represent a phyletic line separate from that including the other murrelets. Cepphus was found to be a member of the phyletic line including Endomychura and Synthliboramphus. Alle was found to be a sister-group of the auks. A compatibility analysis of muscle characters of Hudson et al. (1969) yielded a phylogenetic tree in agreement with that found using my data. The relationships among Cepphus and the murrelets were found to need further study. A classification based on these results is suggested. It is recommended that the recent merging of genera by the A.O.U. (1982) be accepted, that Cyclorrhynchus be merged with Aethia, and that Pinguinus be merged with Alca.
Multiple Paternity in a Territorial Passerine: The Bobolink
Authors: Gavin Thomas A. , Bollinger Eric K.
Published: October 2019

Electrophoretic and behavioral evidence corroborate the conclusion that Bobolink (Dolichonyx oryzivorus) females occasionally copulate with more than one male, which results in the insemination of a single clutch of eggs by those males. In 2 of 12 families from which blood samples were obtained from the mother, the putative father, and the nestlings, at least 2 males were responsible for fertilization of the clutch. We believe this is only the second bird species in which multiple paternity has been documented conclusively in the wild. Our speculation that it may not be uncommon leads to a caution for evolutionary biologists who use apparent reproductive success in birds to address questions about fitness.
Natal Dispersal and Lek Fidelity of Sage Grouse
Authors: Dunn Peter O. , Braun Clait E.
Published: October 2019

Natal dispersal and lek fidelity (attendance within and between years) of Sage Grouse (Centrocercus urophasianus) were studied on Cold Spring Mountain, northwestern Colorado, from July 1981 through May 1984. Female Sage Grouse followed the typical avian pattern of dispersing farther than males. However, there was no difference between proportions of male and female yearling grouse attending the lek closest to their juvenile banding location. Fifteen percent of all individually marked juveniles (24/157 birds) were known to have attended leks as yearlings. There was no difference between yearling and adult lek attendance rates for either sex; however, females attended leks less often than males. Yearling females, but not yearling males, visited 2 or more leks more often than adults. These differences may be related to yearlings' inexperience with breeding or to a strategy to enhance reproductive success.
A Fixed-radius Point Count Method for Nonbreeding and Breeding Season Use
Authors: Hutto Richard L. , Pletschet Sandra M. , Hendricks Paul
Published: October 2019

We provide a detailed description of a fixed-radius point count method that carries fewer assumptions than most of the currently popular methods of estimating bird density and that can be used during both the nonbreeding and breeding seasons. The method results in three indices of bird abundance, any of which can be used to test for differences in community composition among sites, or for differences in the abundance of a given bird species among sites. These indices are (1) the mean number of detections within 25 m of the observer, (2) the frequency of detections within 25 m of the observer, and (3) the frequency of detections regardless of distance from the observer. The overall ranking of species abundances from a site is similar among the three indices, but discrepancies occur with either rare species that are highly detectable at great distances or common species that are repulsed by, or inconspicuous when near, the observer. We argue that differences in the behavior among species will preclude an accurate ranking of species by abundance through use of this or any other counting method in current use.
Daily Activity Patterns of South Polar and Brown Skuas Near Palmer Station, Antarctica
Authors: Pietz Pamela J.
Published: October 2019

I conducted a behavioral study of sympatrically nesting South Polar (Catharacta maccormicki) and Brown skuas (C. lonnbergi) near Palmer Station, Antarctica. A total of 4,058 bird-hours of observations was made on eight South Polar, three Brown, and one mixed-species pair during the 1979-1980 and 1980-1981 austral summers. I used subsets of these data to analyze various aspects of skua activity patterns.

South Polar Skuas exhibited maximum resting and minimum foraging activity during the twilight period around 2400. Brown Skuas appeared to rest and forage more randomly. Members of the mixed pair exhibited patterns similar to those of their respective species. Several hypotheses are suggested to account for species differences in activity patterns; most of these relate dietary differences and differential foraging abilities at low light levels.

In both species, agonistic and preening activities occurred at all hours. South Polar Skuas, however, were most often observed bathing in early afternoon and preening in afternoon and twilight. Pairing activity showed no discernible relationship with time.

Foraging bouts averaged 13 min for Brown Skuas with feeding territories and about 1 h for those without. South Polar Skuas averaged feeding trips of 2-3 h when the sea was open and over 7 h during heavy ice cover.

The timing of an individual's activity was correlated negatively with that of its mate during incubation, brooding, and postbrooding. A nonbreeding pair and breeders that had suffered nest failure showed more positive correlations. Thus, individual activity patterns were shaped by reproductive priorities as well as by feeding ecology and light levels.
Diet Selection by Yearling Northwestern Crows (Corvus caurinus) Feeding on Littleneck Clams (Venerupis japonica)
Authors: Richardson Howard , Verbeek Nicolaas A. M.
Published: October 2019

Yearling and adult Northwestern Crows (Corvus caurinus) used similar methods in searching for buried Japanese littleneck clams (Venerupis japonica) and therefore encountered similar proportions of different-size clams. The mean size of clams eaten by yearling birds was significantly smaller than the mean of those eaten by adults despite the similar proportions encountered. The estimated lower limit of the diet (the smallest clams eaten by the average bird) was 25.5 mm for yearlings and 29.0 mm for adults. Yearlings took more time to find and handle clams and required more drops to break them open than did adults. Consequently, yearlings achieved only one-third the rate of net energy intake of adults feeding from the same food source. However, the extended diet consumed by the yearlings yielded close to the maximum possible rate of energy intake, within the limits imposed by their inefficiency.
Roost Attendance and Aggression in Black Vultures
Authors: Rabenold Patricia Parker
Published: October 2019

In a 5-yr study of a partially marked population of Black Vultures (Coragyps atratus) in North Carolina, turnover among marked birds in a large winter roost averaged 34% each night. Roost attendance and areawide resighting rates differed among age classes; juveniles remained site faithful while young adults ranged far, and adults were intermediate in movement. Local breeders were more consistent in year-round attendance at roosts near their nest sites than were other marked adults using these roosts, and local breeders were likewise overrepresented on initial days at baited feeding sites. During aggressive interactions at roosts and at food, adults won over young birds and juveniles lost to older birds. Breeding adults won more fights close to their nest sites than farther away. Winners of fights at roosts were more likely to be present on subsequent evenings than were losers. The results suggest that food-finding adults, primarily local breeders, can to some extent control local roost membership by means of aggressive interactions in roosts. Successful foragers can reduce the costs of being followed and sharing food by limiting the number and identity of potential followers through aggression.