scholarly journals The chemical basis of a signal of individual identity: shell pigment concentrations track the unique appearance of Common Murre eggs

2019 ◽  
Vol 16 (153) ◽  
pp. 20190115 ◽  
Author(s):  
Mark E. Hauber ◽  
Alexander L. Bond ◽  
Amy-Lee Kouwenberg ◽  
Gregory J. Robertson ◽  
Erpur S. Hansen ◽  
...  
Keyword(s):  
Protoporphyrin Ix ◽  
Chemical Properties ◽  
Group Living ◽  
Individual Variability ◽  
Individual Identity ◽  
Common Murre ◽  
Identity Signalling ◽  
The Individual ◽  
Structural Mechanisms ◽  
Physical And Chemical

In group-living species with parental care, the accurate recognition of one's own young is critical to fitness. Because discriminating offspring within a large colonial group may be challenging, progeny of colonial breeders often display familial or individual identity signals to elicit and receive parental provisions from their own parents. For instance, the common murre (or common guillemot: Uria aalge ) is a colonially breeding seabird that does not build a nest and lays and incubates an egg with an individually unique appearance. How the shell's physical and chemical properties generate this individual variability in coloration and maculation has not been studied in detail. Here, we quantified two characteristics of the avian-visible appearance of murre eggshells collected from the wild: background coloration spectra and maculation density. As predicted by the individual identity hypothesis, there was no statistical relationship between avian-perceivable shell background coloration and maculation density within the same eggs. In turn, variation in both sets of traits was statistically related to some of their physico-chemical properties, including shell thickness and concentrations of the eggshell pigments biliverdin and protoporphyrin IX. These results illustrate how individually unique eggshell appearances, suitable for identity signalling, can be generated by a small number of structural mechanisms.

Synthesis of Cu2O and ZnO Nanowires and their Heterojunction Nanowires by Thermal Evaporation: A Short Review

2014 ◽  
Vol 71 (5) ◽  
Author(s):  
Muhammad Arif Khan ◽  
Samsudi Sakrani ◽  
Syahida Suhaima ◽  
Yussof Wahab ◽  
Rosnita Muhammad
Keyword(s):  
Physical Vapor Deposition ◽  
Thermal Evaporation ◽  
Chemical Properties ◽  
High Sensitivity ◽  
Short Review ◽  
Zno Nanowires ◽  
Oxide Semiconductor ◽  
The Individual ◽  
Photovoltaic Solar Cells ◽  
Physical And Chemical

One dimensional metal oxide semiconductor nanowires of copper (I) oxide (Cu2O), zinc oxide (ZnO), and their heterojunction nanowires possess remarkable physical and chemical properties. ZnO and Cu2O areattractive because the metals are abundant on earth, inexpensive, nontoxic.Moreover, these oxides have useful optical and electrical properties suitable for a wide variety of electrical devices, because their electrical conduction can be predictably controlled by doping. We here restrict the disscussion using a Hot Tube Vacuum Thermal Evaporation. The NWs in these devices will be studied by physical vapor deposition known as vapor-liquid-solid (VLS). Therefore, we explore conventional methods, particularly the VLS of growing ZnO and Cu2O nanowires which are assisted by the catalyst.  In this short review, we report the individual and combined (Cu2O/ZnO) junction nanowires by PVD method.  The main advantages of these composite nanowires are the natural p-n characteristics, the broad light absorption, the high sensitivity to humidity changes, and the fast dynamic response. The combination of all characteristics offered by Cu2O/ZnO nanowires can enable the fabrication of diverse sensing devices, and photovoltaic solar cells.

Isoprene and Rubber. XVII. The Fractionation of Balata

1930 ◽  
Vol 3 (3) ◽  
pp. 511-515
Author(s):  
H. Staudinger ◽  
H. F. Bondy
Keyword(s):  
Molecular Weight ◽  
Natural Products ◽  
High Molecular Weight ◽  
Homologous Series ◽  
Chemical Properties ◽  
Uniform Size ◽  
Gutta Percha ◽  
Synthetic Materials ◽  
The Individual ◽  
Physical And Chemical

Abstract On the basis of earlier experiments with synthetic materials, compounds of high molecular weight are not composed of a single substance, but consist of a mixture of homologous polymers. The individual members of a polymeric homologous series differ very little in physical and chemical properties, and therefore a mixture of polymeric homologous products such as is obtained in the polymerization of the monomer cannot as a rule be decomposed into simple compounds by means of solvents, but merely into mixtures of products of low and high molecular weight. Such separations have been carried out, for example, in the case of polyvinylace-tates, polystyrols, polyindenes, polyanetholes, and polyethyleneoxides. On the basis of these experiments it was assumed that natural products of high molecular weight likewise consist of a mixture of polymeric homologs. Thus purified rubber, for example, according to our views is not such a completely homogeneous hydrocarbon that all the molecules have the same length, but consists of a mixture of perhaps 100 or more polymeric homologs. Pummerer's decomposition of rubber into sol,- and gel-rubber, according to our experiments, is due to the fact that rubber consists of easily soluble polyprenes and difficultly soluble polyprenes, all belonging to the same polymeric homologous series. Of course there is the possibility that, in forming compounds of high molecular weight, nature produced primary molecules of uniform size, and that the mixture of polymeric homologs was formed only later through decomposition. In that case the natural products would differ in constitution from the synthetic material. They would not be polymerically uniform but completely uniform compounds in the sense of classical organic chemistry. The fact that in life processes methods are possible which we cannot realize in the laboratory is well known. Such a finding would not, of course, contradict our former view that natural products, such as rubber and balata, are of high molecular weight in the sense of classical structural chemistry. Our former work has indicated a similar structure for rubber and gutta-percha. Here it is simply a question whether or not the macromolecules of these natural products have a uniform length. In order to reach a decision, we first of all investigated balata, since it is prepared pure more easily than rubber. It was made from balata latex which was supplied to us through the courtesy of the management of the Norddeutsche Seekabelwerke, Nordenham." The balata thus obtained is a flocculent, cellulose-like mass, which looks like gutta-percha and crystallizes like it.

scholarly journals Plasticity of behavioural variability reflects conflicting selection in group-living and solitary desert locusts

2020 ◽  
Author(s):  
Ben Cooper ◽  
Jonathan M. Smith ◽  
Tom Matheson ◽  
Swidbert R. Ott
Keyword(s):  
Empirical Evidence ◽  
Schistocerca Gregaria ◽  
Group Living ◽  
Social Contexts ◽  
Individual Variability ◽  
Intrinsic Variability ◽  
Selection Pressures ◽  
Phase Polyphenism ◽  
Log Normal ◽  
The Individual

Animals living in groups tend to express less variable behaviour than animals living alone. It is widely assumed that this difference reflects, at least in part, an adaptive response to contrasting selection pressures: group-living should favour the evolution of more uniform behaviour whereas lone-living should favour behaviour that is less predictable. Empirical evidence linking these contrasting selection pressures to intrinsic differences in behavioural variability is, however, largely lacking. The desert locust, Schistocerca gregaria, manifests in two very distinct eco-phenotypes, a lone-living cryptic “solitarious phase” and a swarming “gregarious phase” that aggregates into very large and dense groups. This “phase polyphenism” has evolved in response to contrasting selection pressures that change rapidly and unpredictably. Phase differences in mean behaviour are well-characterised, but no previous study has considered differences in variability. Here we used locust phase polyphenism to test the hypothesis that group living leads to the evolution of reduced intrinsic variability in behaviour. We measured two behaviours in both phenotypes: locomotor activity in the presence of conspecifics, and locomotor hesitation in approaching food when alone. We assayed each individual repeatedly and estimated variability relative to the mean in log-normal mixed-effects models that explicitly account for the means-variance dependency in the behavioural measures. Our results demonstrate that relative behavioural variability differs between the two phases in line with predictions from ecological theory: both within-individual and between-individual variability were lower in the group-living gregarious phenotype. This contrasts with previous studies on social niche construction in spiders and crickets, and highlights the importance of social ecology: in animals that form non-social collectives, such as locusts, reduced individual behavioural variability is key for coherent collective behaviour. The differences in variability persisted when gregarious locusts were tested in isolation and solitarious locusts were tested in groups, indicating that they arise not simply as flexible reactions to different social contexts, but are intrinsic to the individual animals of each phase. This “variance polyphenism” in locusts provides empirical evidence that evolutionary adaptation for group living has driven a reduction in within- and between-individual behavioural variability.

scholarly journals In-situ Detection Method for Microplastics in Water by Polarized Light Scattering

2021 ◽  
Vol 8 ◽  
Author(s):  
Tong Liu ◽  
Shijun Yu ◽  
Xiaoshan Zhu ◽  
Ran Liao ◽  
Zepeng Zhuo ◽  
...  
Keyword(s):  
Light Scattering ◽  
Scattered Light ◽  
Polarized Light ◽  
Chemical Properties ◽  
Future Application ◽  
Physical And Chemical Properties ◽  
The Individual ◽  
Physical And Chemical ◽  
And Chemical Properties

Microplastics (MPs) have become the widespread contaminants, which raises concerns on their ecological hazards. In-situ detection of MP in water bodies is essential for clear assessment of the ecological risks of MPs. The present study proposes a method based on polarized light scattering which measures the polarization parameters of the scattered light at 120° to detect MP in water. This method takes the advantage of in-situ measurement of the individual particles and the experimental setup in principle is used. By use of the measured polarization parameters equipped by machine learning, the standard polystyrene (PS) spheres, natural water sample, and lab-cultured microalgae are explicitly discriminated, and MP with different physical and chemical properties can be differentiated. It can also characterize the weathering of different MP and identify the specific type from multiple types of MP. This study explores the capability of the proposed method to detect the physical and chemical properties, weathering state and concentration of MP in water which promises the future application in water quality sensing and monitoring.

Use of Rejuvenators to Rejuvenate Asphalt Binders in RAP

2017 ◽  
Vol 737 ◽  
pp. 547-553
Author(s):  
Iva Krcmova ◽  
Petr Hyzl ◽  
Pavla Nekulova ◽  
Pavel Coufalik ◽  
Ondrej Dasek
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Binder ◽  
Chemical Properties ◽  
Asphalt Binders ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Aged Asphalt ◽  
Empirical Tests ◽  
The Individual ◽  
Physical And Chemical

With increased demand and limited aggregate and binder supply, hot mix asphalt (HMA) producers discovered that reclaimed asphalt pavement (RAP) is a valuable component in HMA. This paper is concerned with the current issue of higher using RAP (Reclaimed Asphalt Pavement) in asphalt mixtures for pavement wearing courses. It describes the effects of application of three types of rejuvenation additives on properties of aged asphalt binders made from a regular RAP. These rejuvenation additives restore the physical and chemical properties of aged binders. In addition, the aged asphalt binder with rejuvenators applied was subjected to a short-term laboratory aging using the RTFOT (Rolling Thin Film Oven Test). This method simulate aging asphalt binder during the manufacturing process and laying. To assess the binder properties, both the standard empirical tests and more advanced functional tests (dynamic shear rheometer and bending beam rheometer) have been performed. Last part of the paper provides an evaluation of the individual rejuvenation additives. Based on the results it can be concluded that a positive change in properties of aged asphalt binder after applying all the three rejuvenators has been proven.

scholarly journals Thin Films of Metal-Organic Framework Interfaces Obtained by Laser Evaporation

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1367
Author(s):  
Olivia L. Rose ◽  
Anca Bonciu ◽  
Valentina Marascu ◽  
Andreea Matei ◽  
Qian Liu ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Metal Organic Framework ◽  
Chemical Properties ◽  
Deposition Process ◽  
Single Step ◽  
Laser Evaporation ◽  
Zeolitic Imidazolate Frameworks ◽  
X Ray ◽  
The Individual ◽  
Physical And Chemical

Properties such as large surface area, high pore volume, high chemical and thermal stability, and structural flexibility render zeolitic imidazolate frameworks (ZIFs) well-suited materials for gas separation, chemical sensors, and optical and electrical devices. For such applications, film processing is a prerequisite. Herein, matrix-assisted pulsed laser evaporation (MAPLE) was successfully used as a single-step deposition process to fabricate ZIF-8 films. By correlating laser fluency and controlling the specific transfer of lab-synthesized ZIF-8, films with user-controlled physical and chemical properties were obtained. Films’ characteristics were evaluated by scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). The analysis showed that frameworks of ZIF-8 can be deposited successfully and controllably to yield polycrystalline films. The deposited films maintained the integrity of the individual ZIF-8 framework, while undergoing minor crystalline and surface chemistry changes. No significant changes in particle size were observed. Our study demonstrated control over both the MAPLE deposition conditions and the outcome, as well as the suitability of the listed deposition method to create composite architectures that could potentially be used in applications ranging from selective membranes to gas sensors.

scholarly journals MALT90 molecular content on high-mass IR-dark clumps

2018 ◽  
Vol 620 ◽  
pp. A158 ◽  
Author(s):  
Gozde Saral ◽  
Marc Audard ◽  
Yuan Wang
Keyword(s):  
Star Formation ◽  
Initial Conditions ◽  
Chemical Properties ◽  
High Mass ◽  
Mass Star ◽  
Physical And Chemical Properties ◽  
Line Widths ◽  
The Individual ◽  
Physical And Chemical ◽  
And Chemical Properties

Context. High mass stars form in groups or clusters in dense molecular clumps with sizes of 1 pc and masses of 200 M⊙. Infrared-dark clumps and the individual cores within them with sizes < 0.1 pc and masses < 100 M⊙ are important laboratories for high-mass star formation in order to study the initial conditions. Aims. We investigate the physical and chemical properties of high-mass clumps in order to better understand the early evolutionary stages and find targets that show star formation signs such as infall motions or outflows. Methods. We selected the high-mass clumps from ATLASGAL survey that were identified as dark at 8/24 μm wavelengths. We used MALT90 Survey data which provides a molecular line set (HCO+, HNC, HCN, N2H+, H13CO+, HN13C, SiO) to investigate the physical and chemical conditions in early stages of star formation. Results. Eleven sources have significant SiO detection (over 3σ) which usually indicates outflow activity. Thirteen sources are found with blue profiles in both or either HCO+ and/or HNC lines and clump mass infall rates are estimated to be in the range of 0.2 × 10−3 M⊙ yr−1 − 1.8 × 10−2 M⊙ yr−1. The excitation temperature is obtained as < 24 K for all sources. The column densities for optically thin lines of H13CO+ and HN13C are in the range of 0.4–8.8 (×1012) cm−2, and 0.9–11.9 (×1012) cm−2, respectively, while it is in the range of 0.1–7.5 (×1014) cm−2 for HCO+ and HNC lines. The column densities for N2H+ were ranging between 4.4–275.7 (×1012) cm−2 as expected from cold dense regions. Large line widths of N2H+ might indicate turbulence and large line widths of HCO+, HNC, and SiO indicate outflow activities. Mean optical depths are 20.32, and 23.19 for optically thick HCO+ and HCN lines, and 0.39 and 0.45 for their optically thin isotopologues H13CO+ and HN13C, respectively. Conclusions. This study reveals the physical and chemical properties of 30 high-mass IR-dark clumps and the interesting targets among them based on their emission line morphology and kinematics.

Utilisation de vecteurs tournants pour l'optimisation de la formulation de mélanges de solvants

2002 ◽  
Vol 80 (4) ◽  
pp. 350-361
Author(s):  
Serge Alex
Keyword(s):  
Chemical Composition ◽  
Physical Properties ◽  
Visual Analysis ◽  
Chemical Properties ◽  
New Strategy ◽  
Halogenated Solvents ◽  
Solvent Blends ◽  
The Individual ◽  
Physical And Chemical ◽  
And Chemical Properties

A new strategy is proposed to optimize the design of solvent blends without using complex mathematical models and (or) graphical representations. All calculations are made with standard electronic programs, such as Excel, Lotus, etc. This approach was developed for the cleaning and degreasing industry, which has to find new recipes of solvent blends on a regular basis. The process relies on a visual analysis of the sum of normalized rotating vectors associated with the chemical composition and the physical properties of the individual components. This approach allows for representation of all parameters on a two-dimensional plot, including information about chemical composition, as well as the physical properties to be optimized. The research of a new mixture of halogenated solvents will be used as an example to illustrate the various steps of this technique. This method is not limited to solvent applications; it also applies to all problems that involve comparisons of physical and chemical properties of blends.Key words: solvents, mixtures, components, optimization, cleaning.

Properties of Rejuvenated RAPs from Stone Mastic Asphalt

2017 ◽  
Vol 863 ◽  
pp. 129-134
Author(s):  
Petr Hyzl ◽  
Iva Krcmova ◽  
Pavla Nekulova ◽  
Ondrej Dasek ◽  
Pavel Coufalik
Keyword(s):  
Asphalt Pavement ◽  
Asphalt Binder ◽  
Chemical Properties ◽  
Asphalt Binders ◽  
Reclaimed Asphalt ◽  
Mastic Asphalt ◽  
Aged Asphalt ◽  
Stone Mastic Asphalt ◽  
The Individual ◽  
Physical And Chemical

Recycling asphalt pavement creates a cycle of reusing materials that optimizes the use of natural resources. Reclaimed asphalt pavement (RAP) is a useful alternative to virgin materials because it reduces the need to use virgin aggregate. This paper is concerned with the current issue of using RAP in Stone Mastic Asphalt (SMA). SMA is a wearing course, which is especially stable and durable. It describes the effects of application of rejuvenators on properties of asphalt binders. These rejuvenation additives restore the physical and chemical properties of aged binders. In addition, the aged asphalt binder with rejuvenators applied was subjected to a short-term laboratory aging using the RTFOT (Rolling Thin Film Oven Test). To assess the binder properties, both the standard empirical tests and more advanced functional tests (dynamic shear rheometer and bending beam rheometer) have been performed. Last part of the paper provides an evaluation of the individual rejuvenation additives. Based on the results it can be concluded that a positive change in properties of aged asphalt binder obtained from a modified RAP (from SMA) after applying all the rejuvenators has been proven. The effect of the rejuvenators during the manufacturing process and laying has been verified.

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