bluuebunny/crossref_metadata_2025 huggingface dataset:
How internal cavities destabilize a protein
Authors: Xue Mengjun , Wakamoto Takuro , Kejlberg Camilla , Yoshimura Yuichi , Nielsen Tania Aaquist , Risør Michael Wulff , Sanggaard Kristian Wejse , Kitahara Ryo , Mulder Frans A. A.
Published: October 2019

Significance

Proteins exist as ensembles of microstates governed by a free energy landscape, with multiple “excited” states coexisting with the minimum energy structure. These alternate folded and partially disordered states are continuously being accessed through protein dynamics and are key elements required for a comprehensive understanding of protein function and stability. Unfortunately, their low abundance makes these “invisible” states hard to characterize experimentally. A unique view of the hierarchy of unfolding states on the protein energy landscape was obtained here using pressure perturbation. Furthermore, pressure perturbation can directly identify empty protein cavities and determine the energetic penalty of filling these with water.
Salicylic acid-mediated plasmodesmal closure via Remorin-dependent lipid organization
Authors: Huang Dingquan , Sun Yanbiao , Ma Zhiming , Ke Meiyu , Cui Yong , Chen Zichen , Chen Chaofan , Ji Changyang , Tran Tuan Minh , Yang Liang , Lam Sin Man , Han Yanhong , Shui Guanghou , Wei Zhuang , Tan Shutang , Liao Kan , Friml Jiří , Miao Yansong , Jiang Liwen , Chen Xu
Published: October 2019

Significance

Plasmodesmata (PD) create cytoplasmic and membrane continuities between adjacent cells to facilitate cell–cell communication and virus movement. Plant cells have evolved diverse mechanisms to regulate PD plasticity against plant pathogens, including the accumulation of the defense hormone, salicylic acid (SA). However, the mechanism of how this occurs is not well understood. Here, we uncover a mechanism by which SA triggers Remorin-dependent membrane lipid nanodomain assembly, leading to enhancement of the liquid-ordered phase. The higher-ordered lipids, which are particularly enriched at PD membrane, decreased PD membrane plasticity, and thus restricted PD opening and impeded virus spreading. Our findings address a knowledge gap in plant defense mechanisms at the membrane level that rely on SA-controlled lipid order and PD closure.
The
cbb
3
-type cytochrome oxidase assembly factor CcoG is a widely distributed cupric reductase
Authors: Marckmann Dorian , Trasnea Petru-Iulian , Schimpf Johannes , Winterstein Christine , Andrei Andreea , Schmollinger Stefan , Blaby-Haas Crysten E. , Friedrich Thorsten , Daldal Fevzi , Koch Hans-Georg
Published: October 2019

Significance

Copper (Cu) is a cofactor of many enzymes in prokaryotes and eukaryotes, but Cu toxicity challenges cuproprotein biogenesis. To prevent Cu-induced damage while sustaining Cu supply for cuproproteins, cells possess sophisticated Cu transport and storage networks. P
1B
-type ATPases and Cu chaperones are central to these networks and preferentially bind Cu(I). However, under aerobic conditions, Cu exists primarily as Cu(II), and hence Cu(II) reduction is essential for Cu transport/storage. Eukaryotic organisms achieve this process via cell-surface exposed metalloreductases. For bacteria, it was generally assumed that the reducing environment of the cytoplasm would suffice to generate Cu(I). However, our findings now show that this dogma is incomplete, as we have identified a bacterial cupric reductase that reduces Cu(II) in the bacterial cytosol.
TCAD simulation studies of novel geometries for CZT ring-drift detectors
Authors: Maneuski D , Gostilo V , Owens A
Published: October 2019

In this work, technology computer-aided design (TCAD) simulation results of new CZT ring-drift detector geometries are presented. The physics model was developed and validated against the results from an existing device which had been comprehensively characterised at x-ray wavelengths. The model was then applied to new detector geometries and a systematic study of the parameters influencing charge collection performed. A comparison between one- two- and three-ring circle and semi-rectangular (or squircle) geometries is presented. In was found that charge collection with the squircle ring configuration was systematically better than the circular configuration and extends approximately

m further from the collecting anode. In addition, a two-ring geometry device is shown to collect charge

m and

m further from the anode when compared to one- and three- ring geometries, respectively. Based on these results, we derive an optimum configuration which potentially can be multiplied on larger crystals, offering an increased charge collection volume without compromising energy resolution.
Superconductivity under pressure in the Dirac semimetal PdTe2
Authors: Leng H , Ohmura A , Anh L N , Ishikawa F , Naka T , Huang Y K , de Visser A
Published: October 2019

The Dirac semimetal PdTe2 was recently reported to be a type-I superconductor (T

c
  =  1.64 K,

mT) with unusual superconductivity of the surface sheath. We here report a high-pressure study,

GPa, of the superconducting phase diagram extracted from ac-susceptibility and transport measurements on single crystalline samples. T

c
(p ) shows a pronounced non-monotonous variation with a maximum T

c
  =  1.91 K around 0.91 GPa, followed by a gradual decrease to 1.27 K at 2.5 GPa. Surface superconductivity is robust under pressure as demonstrated by the large superconducting screening signal that persists for applied dc-fields

. Surprisingly, for

GPa the superconducting transition temperature at the surface

is larger than T

c
of the bulk. Therefore surface superconductivity may possibly have a non-trivial topological nature. We compare the measured pressure variation of T

c
with recent results from band structure calculations and discuss the importance of a Van Hove singularity.
Fréchet differentiable drift dependence of Perron–Frobenius and Koopman operators for non-deterministic dynamics
Authors: Koltai Péter , Lie Han Cheng , Plonka Martin
Published: September 2019

We prove the Fréchet differentiability with respect to the drift of Perron–Frobenius and Koopman operators associated to time-inhomogeneous ordinary stochastic differential equations. This result relies on a similar differentiability result for pathwise expectations of path functionals of the solution of the stochastic differential equation, which we establish using Girsanov’s formula. We demonstrate the significance of our result in the context of dynamical systems and operator theory, by proving continuously differentiable drift dependence of the simple eigen- and singular values and the corresponding eigen- and singular functions of the stochastic Perron–Frobenius and Koopman operators.
First benchmarking of the BIANCA model for cell survival prediction in a clinical hadron therapy scenario
Authors: Carante M P , Aricò G , Ferrari A , Kozlowska W , Mairani A , Ballarini F
Published: October 2019

In the framework of RBE modelling for hadron therapy, the BIANCA biophysical model was extended to O-ions and was used to construct a radiobiological database describing the survival of V79 cells as a function of ion type (1  ⩽  Z  ⩽  8) and energy. This database allowed performing RBE predictions in very good agreement with experimental data. A method was then developed to construct analogous databases for different cell lines, starting from the V79 database as a reference.

Following interface to the FLUKA Monte Carlo radiation transport code, BIANCA was then applied for the first time to predict cell survival in a typical patient treatment scenario, consisting of two opposing fields of range-equivalent protons or C-ions. The model predictions were found to be in good agreement with CHO cell survival data obtained at the Heidelberg ion-beam therapy (HIT) centre, as well as predictions performed by the local effect model (version LEM IV).

This work shows that BIANCA can be used to predict cell survival and RBE not only for V79 and AG01522 cells, as shown previously, but also, in principle, for any cell line of interest. Furthermore, following interface to a transport code like FLUKA, BIANCA can provide predictions of 3D biological dose distributions for hadron therapy treatments, thus laying the foundations for future applications in clinics.
Observation of orbital ordering and origin of the nematic order in FeSe
Authors: Cao R X , Hu Jian , Dong Jun , Zhang J B , Ye X S , Xu Y F , Chareev D A , Vasiliev A N , Wu Bing , Zeng X H , Wang Q L , Wu Guoqing
Published: October 2019

In iron-based superconductors the interactions driving the nematic order that breaks the lattice four-fold rotational symmetry in the iron plane may also facilitate the Cooper pairing, but experimental determination of these interactions is challenging because the temperatures of the nematic order and the order of other electronic phases appear to match each other or to be close to each other. Here we performed field-dependent 77Se-nuclear magnetic resonance (NMR) measurements on single crystals of iron-based superconductor FeSe, with magnetic field B
0 up to 16 T. The 77Se-NMR spectra and Knight shift split when the direction of B
0 is away from the direction perpendicular to the iron planes (i.e. B
0 ∥ c) upon cooling in temperature, with a significant change in the distribution and magnitude of the internal magnetic field at the 77Se nucleus, but these do not happen when B
0 is perpendicular to the iron planes, thus demonstrating that there is an orbital ordering. Moreover, stripe-type antiferromagnetism is absent, while giant antiferromagnetic spin fluctuations measured by the NMR spin-lattice relaxation gradually developed starting at ∼40 K, which is far below the nematic order temperature T
nem = 89 K. These results provide direct evidence of orbital-driven nematic order in FeSe.
Transverse-mode coupling effects in scanning cavity microscopy
Authors: Benedikter Julia , Moosmayer Thea , Mader Matthias , Hümmer Thomas , Hunger David
Published: October 2019

Tunable open-access Fabry–Pérot microcavities enable the combination of cavity enhancement with high resolution imaging. To assess the limits of this technique originating from background variations, we perform high-finesse scanning cavity microscopy of pristine planar mirrors. We observe spatially localized features of strong cavity transmission reduction for certain cavity mode orders, and periodic background patterns with high spatial frequency. We show in detailed measurements that the localized structures originate from resonant transverse-mode coupling and arise from the topography of the planar mirror surface, in particular its local curvature and gradient. We further examine the background patterns and find that they derive from non-resonant mode coupling, and we attribute it to the micro roughness of the mirror. Our measurements and analysis elucidate the impact of imperfect mirrors and reveal the influence of their microscopic topography. This is crucial for the interpretation of scanning cavity images, and could provide relevant insight for precision applications such as gravitational wave detectors, laser gyroscopes, and reference cavities.
Study of Temperature Evolution’s Trend on the Black Sea Shore, at Constanta
Authors: Mocanu-Vargancsik C A , Barbulescu A
Published: September 2019

It is widely recognized that temperature’s changes have an important impact on the environment, in particular on sea waters, plants, animals and human life. This article presents the results of the study of the temperature’s evolution trend in Constanta, the main city and harbour on the Romanian Black Sea shore. Have been used the maximum and minimum daily temperatures, collected from the European Climate Assessment & Dataset project website. The data span over 58 years, from 1961 to 2018, period long enough to consider the results significant. Change points detection is done for annual and seasonal data, followed by testing the trend existence for maximum and minimum annual and seasonal series. The results proved the existence of increasing trend for all the temperature series, fact that confirms the global warming effect in this part of the world.
Single serpentine flow fields design and sub-rib convection analysis for a PEM fuel cell
Authors: Ionescu V
Published: September 2019

In a polymer electrolyte membrane fuel cell (PEMFC), transport of reactant gases through a bypass convection mechanism established between two adjacent channels along the gas diffusion layer (GDL) under the serpentine type flow field of a bipolar plate can enhance the fuel cell performance by reducing the power losses. In this paper, three different serpentine type flow field models for bipolar plates of a PEM fuel cell unit have been designed, with different channel width/rib width ratios of 1, 1.05 and 1.2, and different pressure loses have been evaluated. An analytical model for bypass sub-rib convection, based on two adjacent flow channels and a serpentine in contact with a GDL layer was used here. This model established the influence of bypass convection in the form of Peclet number Pe for the flow field models, by modifying the GDL thickness t (mm) and active channel length L (mm). The optimal combination of thickness t, porosity ε and permeability k for a series of commercial GDL materials from the perspective of sub-rib convection was established for SigracetTM GDL 35 BC, with highest Pe number modified along the channel.
The software package MIEZEPY for the reduction of MIEZE data
Authors: Schober Alexander , Wendl Andreas , Haslbeck Franz X , Jochum Johanna K , Spitz Leonie , Franz Christian
Published: October 2019

Modulation of intensity with zero effort (MIEZE) is a neutron resonant spin echo technique which allows to measure the intermediate scattering function S(Q, τ) under depolarizing conditions. Since MIEZE produces a complex four dimensional dataset, we have developed the software package MIEZEPY to reduce the dataset and extract S(Q, τ) in a user friendly manner. This is an essential step in establishing the MIEZE technique and improving user operation. MIEZEPY was written in Python as an open source package and was developed on GitHub. In this paper the framework and implementation of this package as well as the physical and mathematical principles underlying the data reduction procedure will be introduced to lay out the complexity of this task.
On the dynamics of Riccati foliations with nonparabolic monodromy representations
Authors: Hussenot Desenonges Nicolas
Published: October 2019

In this paper, we study the dynamics of Riccati foliations over noncompact finite volume Riemann surfaces. More precisely, we are interested in two closely related questions: the asymptotic behaviour of the holonomy map

H
o

l
t

(
ω
)

Hol_t(\omega )

defined for every time

t
t

over a generic Brownian path

ω
\omega

in the base; and the analytic continuation of holonomy germs of the foliation along Brownian paths in transversal complex curves. When the monodromy representation is parabolic (i.e., the monodromy around any puncture is a parabolic element in

P
S

L
2

(

C

)

PSL_2(\mathbb {C})

), these two questions have been solved, respectively, in [Comm. Math. Phys. 340 (2015), pp. 433–469] and [Ergodic Theory Dynam. Systems 37 (2017), pp. 1887–1914]. Here, we study the more general case where at least one puncture has hyperbolic monodromy. We characterise the lower-upper, upper-upper, and upper-lower classes of the map

H
o

l
t

(
ω
)

Hol_t(\omega )

for almost every Brownian path

ω
\omega

. We prove that the main result of [Ergodic Theory Dynam. Systems 37 (2017), pp. 1887–1914] still holds in this case: when the monodromy group of the foliation is “big enough”, the holonomy germs can be analytically continued along a generic Brownian path.
Development of a hospital deprescribing implementation framework: A focus group study with geriatricians and pharmacists
Authors: Scott Sion , Twigg Michael J , Clark Allan , Farrow Carol , May Helen , Patel Martyn , Taylor Johanna , Wright David J , Bhattacharya Debi
Published: October 2019

Background

over 50% of older people in hospital are prescribed a pre-admission medicine that is potentially inappropriate; however, deprescribing by geriatricians and pharmacists is limited. This study aimed to characterise geriatricians’ and pharmacists’ barriers and enablers to deprescribing in hospital. It also intended to develop a framework of intervention components to facilitate implementation of hospital deprescribing.

Methods

fifty-four geriatricians and pharmacists representing four UK hospitals attended eight focus groups. We designed a topic guide to invite discussions about barriers and enablers to deprescribing. After thematic analysis, themes were mapped to the theoretical domains framework (TDF), enabling prioritisation of domains for behaviour change. We then identified evidence-based intervention components for changing behaviour within prioritised TDF domains.

Results

geriatricians and pharmacists described several deprescribing enablers in the hospital setting including alignment with their role and generalist knowledge, and routine patient monitoring. Five prioritised TDF domains represent the key barriers and enabler: patient and caregiver attachment to medication (social influence); perceptions that deprescribing is riskier than continuing to prescribe (beliefs about consequences); pharmacists’ working patterns limiting capacity to support deprescribing (environmental context and resources); deprescribing being a low hospital priority (goals) and incentives to deprescribe (reinforcement). Prioritised TDF domains aligned with 44 evidence-based intervention components to address the barriers and enabler to hospital deprescribing.

Conclusion

the behavioural determinants and their associated intervention components provide a hospital deprescribing implementation framework (hDIF). Intervention components should be selected from the hDIF to provide a theory and evidence-based intervention tailored to hospital contexts.
Statin treatment, phenotypic frailty and mortality among community-dwelling octogenarian men: the HBS cohort
Authors: Luotola Kari , Jyväkorpi Satu , Urtamo Annele , Pitkälä Kaisu H , Kivimäki Mika , Strandberg Timo E
Published: October 2019

Background

statin treatment has increased also among people aged 80 years and over, but adverse effects potentially promoting frailty and loss of resilience are frequent concerns.

Methods

in the Helsinki Businessmen Study, men born in 1919–34 (original n = 3,490) have been followed up since the 1960s. In 2011, a random subcohort of home-living survivors (n = 525) was assessed using questionnaires and clinical (including identification of phenotypic frailty) and laboratory examinations. A 7-year mortality follow-up ensued.

Results

we compared 259 current statin users (median age 82 years, interquartile range 80–85 years) with 266 non-users (83; 80–86 years). Statin users had significantly more multimorbidity than non-users (prevalencies 72.1% and 50.4%, respectively, P < 0.0001) and worse glucose status than non-users (prevalencies of diabetes 19.0% and 9.4%, respectively, P = 0.0008). However, there was no difference in phenotypic frailty (10.7% versus 11.2%, P = 0.27), and statin users had higher plasma prealbumin level than non-users (mean levels 257.9 and 246.3 mg/L, respectively, P = 0.034 adjusted for age, body mass index and C-reactive protein) implying better nutritional status. Despite morbidity difference, age-adjusted 7-year mortality was not different between the two groups (98 and 103 men among users and non-users of statins, respectively, hazard ratio 0.96, 95% confidence interval 0.72–1.30).

Conclusions

our study suggests that male octogenarian statin users preserved resilience and survival despite multimorbidity, and this may be associated with better nutritional status among statin users.
Comparison of Approaches for Equating Different Versions of the Mini-Mental State Examination Administered in 22 Studies
Authors: Gross Alden L , Kueider-Paisley Alexandra M , Sullivan Campbell , Schretlen David ,   International Neuropsychological Normative Database Initiative
Published: October 2019

The Mini-Mental State Examination (MMSE) is one of the most widely used cognitive screening tests in the world. However, its administration and content differs by country and region, precluding direct comparison of scores across different versions. Our objective was to compare 2 methods of deriving comparable scores across versions of the MMSE. Between 1981 and 2012, investigators in the International Neuropsychological Normative Database Initiative collected MMSE scores on 122,512 persons from 47 studies conducted in 35 countries. We used MMSE data from 80,559 adults aged 41–99 years from 22 studies that provided item-level response data. We first equated 14-point, 15-point, 18-point, 19-point, and 23-point versions of the MMSE to the original 30-point version using coarse equipercentile equating methods that preserved differences across continents, age groups, and durations (years) of education. We then derived more precise item response theory–based scores using item-level responses to MMSE component items. We compared the 2 score-equating approaches using correlation and Bland-Altman plots. Both test-equating approaches were highly correlated with each other (r = 0.73) and with raw MMSE point totals. Bland-Altman plots revealed minimal evidence of systematic differences between the approaches. Our findings support the use of equipercentile equating when item-level data are unavailable to facilitate development of international test norms.
Pollination intensity and paternity in flowering plants
Authors: Christopher Dorothy A , Mitchell Randall J , Karron Jeffrey D
Published: October 2019

Background

Siring success plays a key role in plant evolution and reproductive ecology, and variation among individuals creates an opportunity for selection to act. Differences in male reproductive success can be caused by processes that occur during two stages, the pollination and post-pollination phases of reproduction. In the pollination phase, heritable variation in floral traits and floral display affect pollinator visitation patterns, which in turn affect variation among plants in the amount of pollen exported and deposited on recipient stigmas. In the post-pollination phase, differences among individuals in pollen grain germination success and pollen tube growth may cause realized paternity to differ from patterns of pollen receipt. The maternal plant can also preferentially provision some developing seeds or fruits to further alter variation in siring success.

Scope

In this review, we describe studies that advance our understanding of the dynamics of the pollination and post-pollination phases, focusing on how variation in male fitness changes in response to pollen limitation. We then explore the interplay between pollination and post-pollination success, and how these processes respond to ecological factors such as pollination intensity. We also identify pressing questions at the intersection of pollination and paternity and describe novel experimental approaches to elucidate the relative importance of pollination and post-pollination factors in determining male reproductive success.

Conclusions

The relative contribution of pollination and post-pollination processes to variation in male reproductive success may not be constant, but rather may vary with pollination intensity. Studies that quantify the effects of pollination and post-pollination phases in concert will be especially valuable as they will enable researchers to more fully understand the ecological conditions influencing male reproductive success.
Predicting Public Interest in Nonsurgical Cosmetic Procedures Using Google Trends
Authors: Tijerina Jonathan D , Morrison Shane D , Nolan Ian T , Parham Matthew J , Nazerali Rahim
Published: October 2019

Background

Google Trends (GT) provides cost-free, customizable analyses of search traffic for specified terms entered into Google’s search engine. GT may inform plastic surgery marketing decisions and resource allocation.

Objectives

The aim of this study was to determine GT’s utility in tracking and predicting public interest in nonsurgical cosmetic procedures and to examine trends over time of public interest in nonsurgical procedures.

Methods

GT search volume for terms in 6 ASPS and ASAPS nonsurgical procedure categories (Botox injections, chemical peel, laser hair removal, laser skin resurfacing, microdermabrasion and soft tissue fillers [subcategories: collagen, fat, and hyaluronic acid]) were compared with ASPS and ASAPS case volumes for available dates between January 2004 and March 2019 with the use of univariate linear regression, taking P < 0.01 as the cutoff for significance.

Results

Total search volume varied by search term within the United States and internationally. Significant positive correlations were demonstrated for 17 GT terms in all 6 ASPS and ASAPS categories: “Botox®,” “collagen injections,” “collagen lip injections” with both databases; and “chemical skin peel,” “skin peel,” “acne scar treatment,” “CO2 laser treatment,” “dermabrasion,” “collagen injections,” “collagen lip injections,” “fat transfer,” “hyaluronic acid fillers,” “hyaluronic acid injection,” “hyaluronic acid injections,” “Juvederm®,” and “fat transfer” with just 1 database. Many search terms were not significant, emphasizing the need for careful selection of search terms.

Conclusions

Our analysis further elaborates on recent characterization of GT as a powerful and intuitive data set for plastic surgeons, with the potential to accurately gauge global and national interest in topics and procedures related to nonsurgical cosmetic procedures.
The Function of Singing in Female Black-Headed Grosbeaks (Pheucticus melanocephalus): Family-Group Maintenance
Authors: Ritchison Gary
Published: September 2019

The responses of young Black-headed Grosbeaks (Pheucticus melanocephalus) to playback of the songs of parents and strangers were examined. I found that young grosbeaks moved about more, called more, and were more often oriented toward speakers in response to parental song (both male and female) than in response to the songs of strangers. I suggest that such a response is part of a system used by Black-headed Grosbeaks to maintain family groups after the young fledge. In this system, an adult with food, but unaware of the location of its young, sings to elicit begging from its young. The parent bird is then able to locate and feed its young.
Adaptations of the Gray Catbird Dumetella carolinensis to Long Distance Migration: Energy Stores and Substrate Concentrations in Plasma
Authors: Marsh Richard L.
Published: October 2019

The major body components (water, lean dry, and fat) were measured in the carcasses of Gray Catbirds from which the flight muscles had been removed. Birds were collected from May through October near Ann Arbor, Michigan and during September and October near Gainesville, Florida. Additionally, the glycogen content of muscle and liver and the concentrations of glucose and triglycerides in plasma were determined in catbirds sampled during fall migration in Florida. Catbirds attained maximum body masses of ∼50 g in Florida, largely due to the addition of fat. Relatively lean birds (∼3-4% body fat) in spring through fall weighed approximately 35 g. Thirteen percent of the birds sampled were estimated to have had sufficient reserves of fat to cross the Gulf of Mexico, although a larger proportion of the population probably makes this crossing. The lean dry mass of the carcass (without the flight muscles) is related significantly to structural body size and time of day, but is not related to molt, sex, or carcass fat content. Plasma glucose and triglycerides in free-living fall migrants do not vary diurnally. Liver glycogen, however, is four times higher in the evening than in the morning (77 and 19 mg/g, respectively), and muscle glycogen is five times higher in the evening (20 and 4 mg/g, respectively). Evening concentrations of glycogen are among the highest values reported for birds and do not confirm the reduction in glycogen reported for some other migrants.
Behavior, Morphology, and Systematics of Sirystes sibilator (Tyrannidae)
Authors: Lanyon Wesley E. , Fitzpatrick John W.
Published: October 2019

Field and laboratory studies support recent hypotheses that Sirystes sibilator is closely allied with the myiarchine flycatchers rather than with Tyrannus or with the cotingids. The first confirmed nest of this tyrant (located in a natural tree cavity), its foraging behavior, and the derived character states of the nasal septum and of the syrinx argue convincingly for its placement in an assemblage with Myiarchus, Rhytipterna, and Casiornis. Data, still lacking, on the color of the eggs and nature of the nest lining are needed for Sirystes (and for Rhytipterna and Casiornis) before consideration can be given to the generic relationships within the myiarchine flycatchers.
The Pallid Falcon Falco kreyenborgi Is a Color Phase of the Austral Peregrine Falcon (Falco peregrinus cassini)
Authors: Ellis David H. , Garat Cesar Peres
Published: September 2019

The Pallid Falcon (Falco kreyenborgi), a rare form from southern Patagonia and Tierra del Fuego, has, since its discovery in 1925, gained acceptance as a full species. In 1981, we observed 13 Pallid Falcons on the Patagonian Steppe. Four adult Pallid Falcons were paired with normal Peregrine Falcon (Falco peregrinus cassini) mates. Two normal-phased peregrine pairs produced mixed broods of normal and pallid young. One pair of pallid adults produced only pallid young. These observations lead to the conclusion that the Pallid Falcon is conspecific with and a color phase of the Peregrine Falcon.
Brown Pelican Foraging Success and Kleptoparasitism by Laughing Gulls
Authors: Schnell Gary D. , Woods Barbara L. , Ploger Bonnie J.
Published: October 2019

Previous studies have shown age-related differences in feeding success for a number of bird species, particularly those found in marine environments. We compared the foraging success of adult and immature Brown Pelicans (Pelecanus occidentalis) feeding along the Playa Miramar northwest of Manzanillo, Colima, Mexico. On many of the feeding dives, Laughing Gulls (Larus atricilla) were attracted to pelicans and often behaved aggressively in attempts to obtain food from them. Adult Brown Pelicans were significantly more successful than immatures. Laughing Gulls were attracted to successful pelicans regardless of the age of the pelican. The proportion of unsuccessful immature pelicans not attracting gulls was higher than that of unsuccessful adult pelicans. Particularly inept immature pelicans are probably easily identified by gulls and ignored completely. Although we found no differences in the frequency of pelican-gull physical contact (which we used as a measure of gull aggressiveness) between immature and adult pelicans, such behavior was directed almost exclusively toward successful pelicans. Gull aggression was also more intense when pelicans were attacked by groups of gulls.
On the Use of Avian Mortality Patterns to Test Sexual Selection Theory
Authors: Weatherhead Patrick J. , Greenwood Hamilton , Clark Robert G.
Published: October 2019

To test the hypothesis that reduced survival of large males limits the extent to which sexual selection can increase male size, we examined mortality patterns in Redwinged Blackbirds (Agelaius phoeniceus) subjected to a surfactant spray. Univariate comparisons of wing measurements did not support the predicted mortality patterns. Although principal component analysis revealed that mortality was nonrandom with respect to some morphological characters, there was again no evidence of the predicted patterns either of directional selection favoring smaller males or of stabilizing selection favoring intermediatesized females. This result led us to recognize that, like previous authors, we had made the incorrect assumption that large males should be more vulnerable to all mortality factors rather than the correct interpretation of the theory, that differential mortality should be seen as the net effect of all mortality factors. Only two published data sets are appropriate for testing the hypothesis, and neither shows differential mortality amongst males on the basis of size.
Reproductive Energetics of Two Tropical Bird Species
Authors: Bryant D. M. , Hails C. J. , Tatner P.
Published: October 2019

Daily energy expenditure (DEE) during breeding was studied in Pacific Swallows (Hirundo tahitica) and Blue-throated Bee-eaters (Merops viridis) in Malaysia. DEE was measured directly by the doubly labelled water (D218O) technique and indirectly by TAL (time-activity-laboratory) methods during the time adults were feeding their young at the nest. DEE was 76.6 kJ/day in the Pacific Swallow and 77.4 kJ/day in the larger Blue-throated Bee-eater (D218O results). The relatively low DEE, compared to temperate-zone insectivores that also feed in flight, was attributed to the action of proximate factors, namely a more favorable thermal environment and shorter days (which results in less daytime activity). In bee-eaters, partial use of a low-cost foraging technique also contributed to their lower DEE. The suitability of DEE as a measure of reproductive effort is discussed.
Must Desert Chukars (Alectoris chukar sinaica) Drink Water? Water Influx and Body Mass Changes in Response to Dietary Water Content
Authors: Degen A. Allan , Pinshow Berry , Shaw Peter J.
Published: October 2019

The Chukar subspecies Alectoris chukar sinaica inhabits the Negev desert, which is characterized by hot, dry summers, and little winter rainfall. Vegetation is dry and dormant during the summer and autumn; green, succulent vegetation is available following winter rain. We studied whether or not and under what dietary conditions Chukars require drinking water. Four groups of Chukars in an outdoor aviary received either a dry ration + water, a dry ration + green vegetation, a dry ration + green vegetation + water, or green vegetation only.

The birds offered only greens lost 15% of their body mass in the first 8 days and 2.9% over the next 6 days, while birds on the other three treatments maintained body mass. The birds receiving only greens had the highest total body water to body mass ratio and the highest water influx. We concluded that the Chukars receiving only green vegetation met their water requirements but not their maintenance energy requirements. Chukars fulfilled both their water and energy requirements on a dry ration + green vegetation (without drinking water); the green vegetation comprised approximately 60% of their total fresh matter intake, or 26% of their total dry matter intake. Our analysis suggests that wild desert Chukars do not require drinking water from early winter to late spring, when succulent forage is available, but probably need free water during summer and autumn, when the bulk of their diet is seeds.
Karyotypic Evolution and Long-Term Effective Population Sizes of Birds
Authors: Barrowclough George F. , Shields Gerald F.
Published: October 2019

Rates of karyotypic change in birds are used to estimate that, over the longterm history of a wide assortment of genera, avian effective population sizes have averaged on the order of 100. This result is consistent with the results of electrophoretic studies of geographic variation of allelic frequencies within species but is somewhat less consistent with the results obtained from demographic modeling. Three methodologically independent analyses have now corroborated the hypothesis that avian effective population sizes are typically of the order of 102 or larger.
Daily Energy Expenditure of Savannah Sparrows: Comparison of Time-Energy Budget and Doubly-Labeled Water Estimates
Authors: Williams Joseph B. , Nagy Kenneth A.
Published: October 2019

Using the doubly-labeled water (DLW) technique, we measured the CO2 production of six free-living male Savannah Sparrows (Passerculus sandwichensis, mean mass 19.1 g) and found a mean (Â±1 SD) of 7.28 Â± 1.36 ml ${\rm CO}_{2}/{\rm h}$. Assuming an R.Q. of 0.85 and 24 J/ml CO2, we calculated a mean $\dot{H}_{TD}$ (daily energy expenditure) of 80.3 Â± 16.6 kJ/day. Simultaneously to our DLW measurements, we constructed time budgets for the sparrows during their normal activities with the intent of exploring the agreement between predictions of a number of time-energy budget (TEB) models from the literature and DLW measurements. Our results reveal that several models yield reasonable results, the mean value for the models of Kendeigh et al. (1977), Walsberg (1977), and Mugaas and King (1981) differing from DLW measurements by only +4.7, -5.6%, and +5.7%, respectively. Comparisons of $\dot{H}_{TD}$ as predicted by these TEB models between species and within species between nesting phases might be made with some confidence. However, the variation in TEB estimates is not related to variation in DLW measurements within our study. This precludes statements about differences between individuals.
Nutrient Reserve Dynamics of Breeding and Molting Brant
Authors: Ankney C. Davison
Published: October 2019

I collected 150 Brant (Branta bernicla) at East Bay, Southampton Island, Northwest Territories, Canada, in 1979 and 1980 to evaluate how much these birds rely on reserves of fat, protein, and calcium during egg production, incubation, and the subsequent wing molt. Egg laying resulted in decreases in body weight and nutrient reserves of females. These decreases could have accounted for all of the fat but only 70% of the protein in an average clutch. Neither males nor females had sufficient reserves when incubation began to enable them to fast during that period. Only 11% and 22% of the energy required by males and females, respectively, could have been derived from their reserves during incubation. Brant evidently did not use body reserves to obtain nutrients for feather growth during wing molt. Rather, molting males and females accumulated muscle protein, which supports my hypothesis that wing molt is not a nutritional stress for waterfowl.
Foraging Success and Tree Species Use in the Least Flycatcher
Authors: Rogers Christopher M.
Published: October 2019

I examined the effect of tree species morphology on foraging behavior in a hover-gleaning bird species, the Least Flycatcher (Empidonax minimus). Birds in four breeding territories in northern Wisconsin displayed nonsignificant differences in an index of foraging success (S) among four tree species of divergent morphology. However, significant variation in S occurred among the three tree species common to all four territories; in addition, multiple comparisons indicated that S values in Betula papyrifera were significantly greater than those in Acer spp. or Quercus spp. Despite its statistical significance, variation in S was not large, and flycatchers used available tree species in general accordance with their abundances. No significant correlation was found between S and tree species use. These results are not immediately consistent with an emerging perspective of avian community structure that predicts that hover-gleaners, unlike gleaners, should be affected little by foliage morphology. Foraging efficiency and prey depletion in initially favored tree species are proximate factors possibly linked to breadth of tree species use.
Nesting Success and Mortality of the Boat-Tailed Grackle
Authors: Bancroft G. Thomas
Published: October 2019

Of 605 Boat-tailed Grackle (Quiscalus major) nests with complete clutches, 60.5% fledged young. Survival of nests to the hatching stage averaged 78.7%, and survival from hatching to fledging averaged 76.9%. Nesting success between localities varied from none to almost all nests fledging some young. Fledging success for 3-egg clutches averaged 64.8% and was significantly higher than the 50.8% success rate that 2-egg clutches averaged. Individual survival of eggs from laying through hatching was lower in 2-egg clutches than in 3-egg clutches, but from hatching to fledging nestling survival was higher. Thus, in contrast to nest survival, equal proportions of eggs in 2- and 3-egg clutches produced fledglings.

Predation was the greatest source of mortality, with predators taking 14.8% of the 1,605 eggs and 13.1% of the 1,145 nestlings. Of eggs that survived to the hatching stage, 9.2% failed to hatch. Starvation (13.4%) was the most common source of nestling mortality. Nest abandonment accounted for the death of 5.7% of the eggs and 2.9% of the young. The sources of mortality varied spatially and temporally in an unpredictable way. This uncertainty has resulted in the flexible nesting biology of grackles.
Old Age and Breeding Behavior in a Tropical Passerine Bird Ploceus cucullatus under Controlled Conditions
Authors: Collias N. E. , Collias E. C. , Jacobs C. H. , Cox C. R. , McAlary F. A.
Published: October 2019

Many tropical species of passerine birds have potentially long reproductive lives in both nature and aviaries, but rate of breeding by old individuals may eventually decline. A group of individually color-banded African Village Weavers (Ploceus cucullatus), a polygynous species, was kept in aviaries at Los Angeles for 22 years. At 14-18 years of age, old males built significantly fewer nests per year, displayed to females less often, had fewer mates, and generally fathered fewer clutches than did the same males when 9-13 years old. One male reached 24 years of age, when he rarely sang and no longer wove when provided with nest materials. The females, after reaching "middle age" (9-13 yr), laid significantly fewer eggs per year, and still fewer during "old age" (14-18 yr). When 14 or more years old, weavers of both sexes rested much more than did young adults 4-6 years old in the same aviary.

Individuals differed greatly in the decline of breeding behavior with age. Some individual Village Weavers bred at a surprisingly great age for passerine birds, e.g. fertile copulations by one 19-year-old male and by one 18-year-old female. These seem to be the oldest breeding ages yet recorded for any small passerine bird. Long reproductive life of a small number of individuals that contribute disproportionately to the next generation would give a selection pressure for longevity, and also could help explain the evolution of small clutch size (2-3 eggs) in the Village Weaver and in many other tropical birds.
Energy Metabolism in the Locomotor Muscles of the Common Murre (Uria aalge) and the Atlantic Puffin (Fratercula arctica)
Authors: Davis M. Benjamin , Guderley Helga
Published: October 2019

To compare the metabolic systems that support the combination of flying and diving with those used to support burst flying and sustained flying, myoglobin concentrations and maximum enzyme activities were determined for selected enzymes of glycolysis, the Krebs cycle, and amino acid metabolism in the pectoral, supracoracoideus, and sartorius muscles of the Common Murre (Uria aalge), Atlantic Puffin (Fratercula arctica), Rock Dove (Columba livia; hereafter "pigeon"), and Ring-necked Pheasant (Phasianus colchicus). Glycolytic enzyme levels in the flight muscles were lower in the murre and the puffin than in the pheasant, while both glycolytic and Krebs-cycle enzyme levels resembled those in the pigeon. We believe puffins and murres do not rely extensively on anaerobic glycolysis during diving. In concordance with a role in oxygen storage for diving, the levels of myoglobin in the flight muscles of murres and puffins were higher than those in pigeons or pheasants. They were lower than published values for penguins, however. In contrast to the trends for pigeon and pheasant muscles, the alcid sartorius muscles had a considerably lower aerobic orientation than the flight muscles.
Dispersal Patterns of Western Gulls from Southeast Farallon Island
Authors: Spear Larry B.
Published: September 2019

During 1978-1981 I studied age- and sex-related dispersal and foraging patterns of Western Gulls (Larus occidentalis) that breed on Southeast Farallon Island, California. Most adults were sedentary and foraged primarily on oceanic food during all seasons except autumn, when human refuse was of major importance. Autumn was the only period when adults did not maintain breeding territories, and also the time of primary molt when flight capabilities were reduced. During the breeding season many subadults moved north to areas where oceanic productivity is high. During autumn/winter most moved south to the Gulf of the Farallons/San Francisco Bay Area, where birds ate both oceanic food and refuse. Dispersal patterns of first-year gulls varied markedly between years, apparently as a result of annual differences in oceanic productivity. The consistency of movement patterns of other age classes resulted from an age-related increase in fidelity to foraging locations. This was most pronounced in adults. Most adults dispersed each year to the same site, and minimized competition by reducing concentrations at each location. Males were more sedentary than females, probably because they are responsible for securing and holding breeding territories.
Genetic and Morphological Differentiation and Phylogeny in the Australo-Papuan Scrubwrens (Sericornis, Acanthizidae)
Authors: Christidis Leslie , Schodde Richard , Baverstock Peter R.
Published: October 2019

The interrelationships of 13 of the 14 species currently recognized in the Australo-Papuan oscinine scrubwrens, Sericornis, were assessed by protein electrophoresis, screening 44 presumptive loci. Consensus among analyses indicated that Sericornis comprises two primary lineages of hitherto unassociated species: S. beccarii with S. magnirostris, S. nouhuysi and the S. perspicillatus group; and S. papuensis and S. keri with S. spilodera and the S. frontalis group. Both lineages are shared by Australia and New Guinea. Patterns of latitudinal and altitudinal allopatry and sequences of introgressive intergradation are concordant with these groupings, but many features of external morphology are not. Apparent homologies in face, wing and tail markings, used formerly as the principal criteria for grouping species, are particularly at variance and are interpreted either as coinherited ancestral traits or homoplasies.

Distribution patterns suggest that both primary lineages were first split vicariantly between Australia and New Guinea, and then radiated independently on each land mass under the influence of paleoclimatic change. Dispersal between Australia and New Guinea is indicated only in the magnirostris sublineage and is either very recent or just broken.