scholarly journals Size matters: micro-evolution in Polynesian rats highlights body size changes as initial stage in evolution

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9076
Author(s):  
Alexandra A.E. van der Geer
Keyword(s):  
Temporal Distribution ◽  
Shape Variation ◽  
Mammal Species ◽  
Canonical Variates Analysis ◽  
Ecological Release ◽  
Initial Stage ◽  
Evolutionary Allometry ◽  
Canonical Variates ◽  
Coordinate Data

Microevolutionary patterns in populations of introduced rodent species have often been the focus of analytic studies for their potential relevance to understanding vertebrate evolution. The Polynesian rat (Rattus exulans) is an excellent proxy species because of its wide geographic and temporal distribution: its native and introduced combined range spans half the globe and it has been living for at least seven centuries wherever it was introduced. The objective of this study was to assess the effects of long-term isolation (insularity; up to 4,000 years) and geographic variables on skull shape variation using geometric morphometrics. A sample of 513 specimens from 103 islands and four mainland areas was analysed. This study, to my knowledge the first to extensively sample introduced rats, analysed 59 two-dimensional landmarks on the skull. Landmarks were obtained in three separate aspects (dorsal, lateral, ventral skull view). The coordinate data were then subjected to a multivariate ordination analysis (principal components analysis, or PCA), multivariate regressions, and a canonical variates analysis (CVA). Three measures of disparity were evaluated for each view. The results show that introduced Polynesian rats evolve skull shapes that conform to the general mammalian interspecific pattern of cranial evolutionary allometry (CREA), with proportionally longer snouts in larger specimens. In addition, larger skulls are more tubular in shape than the smaller skulls, which are more balloon-shaped with a rounder and wider braincase relative to those of large skulls. This difference is also observed between the sexes (sexual dimorphism), due to the slightly larger average male size. Large, tubular skulls with long snouts are typical for Polynesia and Remote Oceania, where no native mammals occur. The greater disparity of Polynesian rats on mammal species-poor islands (’exulans-only’ region) provides further insight into how diversity may affect diversification through ecological release from predators and competitors.

Phenotypic variation of south-western Atlantic clam Mactra isabelleana (Bivalvia: Mactridae)

2012 ◽  
Vol 93 (2) ◽  
pp. 511-517 ◽  
Author(s):  
Javier H. Signorelli ◽  
Federico Márquez ◽  
Guido Pastorino
Keyword(s):  
Principal Component ◽  
Shell Shape ◽  
Physical Parameters ◽  
Buenos Aires Province ◽  
Shape Variation ◽  
Geometric Morphometric ◽  
Western Atlantic ◽  
Canonical Variates Analysis ◽  
Canonical Variates ◽  
Geometric Morphometric Method

The phenotypic shell shape variation of Mactra isabelleana was tested using the geometric morphometric method. Four localities were sampled along the Río de la Plata estuary and the coast of Buenos Aires province. Principal component analysis and canonical variates analysis of the first principal components were performed to reveal the shell variation and differences among localities, respectively. The specimens from different microhabitats mostly overlapped, although differences in shape were observed in the development of the umbo, the enlargement of the dorsoventral axes and the elongation of the posterior end. The ecological and physical parameters that could influence shell shape variation are discussed.

Clonal structure and fertility in a sympatric population of the peat mosses Sphagnum rubellum and Sphagnum capillifolium

1996 ◽  
Vol 74 (9) ◽  
pp. 1375-1385 ◽  
Author(s):  
Nlls Cronberg
Keyword(s):  
Leaf Shape ◽  
Morphological Characters ◽  
Clonal Structure ◽  
Shape Variation ◽  
Canonical Variates Analysis ◽  
Hierarchical Structuring ◽  
Canonical Variates ◽  
Self Fertilization ◽  
The Mean ◽  
A Site

Data from isozyme and leaf shape variation are combined to explore the clonal structure at a site where hybridization between Sphagnum rubellum and Sphagnum capillifolium was previously indicated. Shoots of both species were sampled at 10-cm intervals along seven transects across different hummocks. Allelic data from 13 enzyme systems revealed 22 multilocus genotypes representing different clones, 18 being S. capillifolium and 4 being S. rubellum. The mean ± SE and maximum clonal length were 35 ± 8 cm and 160 cm, respectively. The sets of alleles found in the progeny of S. capillifolium were identical to the maternal complement of alleles in 78% of the material, indicating either self-fertilization or fertilization by a male with the same set of alleles at the screened loci. Outcrossing was detected in six cases. Patterns of differentiation and the hierarchical structuring of diversity among species, transects, and clones were analysed with canonical variates analysis using stem-leaf characters. A stronger relative differentiation was found between transects than between species. Clones identified by electrophoresis were usually morphologically well defined. Hybridization was indicated by morphological characters, occasional misplaced alleles, and signs of developmental instability. Keywords: allozymes, computerized image analysis, breeding system, clonal structure, Sphagnum rubellum, Sphagnum capillifolium.

Long-term stress level in a small mammal species undergoing range expansion

Mammalia ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Adrien André ◽  
Johan Michaux ◽  
Jorge Gaitan ◽  
Virginie Millien
Keyword(s):  
Stress Level ◽  
Species Distribution ◽  
Small Mammal ◽  
Range Expansion ◽  
Mammal Species ◽  
Distribution Ranges ◽  
Northern Edge ◽  
Small Mammal Species ◽  
White Footed Mouse

Abstract Rapid climate change is currently altering species distribution ranges. Evaluating the long-term stress level in wild species undergoing range expansion may help better understanding how species cope with the changing environment. Here, we focused on the white-footed mouse (Peromyscus leucopus), a widespread small mammal species in North-America whose distribution range is rapidly shifting northward. We evaluated long-term stress level in several populations of P. leucopus in Quebec (Canada), from the northern edge of the species distribution to more core populations in Southern Quebec. We first tested the hypothesis that populations at the range margin are under higher stress than more established populations in the southern region of our study area. We then compared four measures of long-term stress level to evaluate the congruence between these commonly used methods. We did not detect any significant geographical trend in stress level across our study populations of P. leucopus. Most notably, we found no clear congruence between the four measures of stress level we used, and conclude that these four commonly used methods are not equivalent, thereby not comparable across studies.

scholarly journals A Novel Deep Learning Approach for Machinery Prognostics Based on Time Windows

2019 ◽  
Vol 9 (22) ◽  
pp. 4813 ◽  
Author(s):  
Hanbo Yang ◽  
Fei Zhao ◽  
Gedong Jiang ◽  
Zheng Sun ◽  
Xuesong Mei
Keyword(s):  
Time Windows ◽  
Remaining Useful Life ◽  
Sensor Data ◽  
Time Interval ◽  
Kernel Module ◽  
Initial Stage ◽  
Research Task ◽  
Consecutive Time ◽  
Useful Life

Remaining useful life (RUL) prediction is a challenging research task in prognostics and receives extensive attention from academia to industry. This paper proposes a novel deep convolutional neural network (CNN) for RUL prediction. Unlike health indicator-based methods which require the long-term tracking of sensor data from the initial stage, the proposed network aims to utilize data from consecutive time samples at any time interval for RUL prediction. Additionally, a new kernel module for prognostics is designed where the kernels are selected automatically, which can further enhance the feature extraction ability of the network. The effectiveness of the proposed network is validated using the C-MAPSS dataset for aircraft engines provided by NASA. Compared with the state-of-the-art results on the same dataset, the prediction results demonstrate the superiority of the proposed network.

scholarly journals FCCSP IMC growth under reliability stress follows automotive criteria

2019 ◽  
Vol 3 (1) ◽  
pp. 70-83
Author(s):  
Wei Wei Liu ◽  
Berdy Weng ◽  
Scott Chen
Keyword(s):  
High Temperature ◽  
Flip Chip ◽  
Stress Test ◽  
Temperature Cycling ◽  
Content Type ◽  
Initial Stage ◽  
High Temperature Storage ◽  
Temperature Cycling Test ◽  
Temperature Storage

Purpose The Kirkendall void had been a well-known issue for long-term reliability of semiconductor interconnects; while even the KVs exist at the interfaces of Cu and Sn, it may still be able to pass the condition of unbias long-term reliability testing, especially for 2,000 cycles of temperature cycling test and 2,000 h of high temperature storage. A large number of KVs were observed after 200 cycles of temperature cycling test at the intermetallic Cu3Sn layer which locate between the intermetallic Cu6Sn5 and Cu layers. These kinds of voids will grow proportional with the aging time at the initial stage. This paper aims to compare various IMC thickness as a function of stress test, the Cu3Sn and Cu6Sn5 do affected seriously by heat, but Ni3Sn4 is not affected by heat or moisture. Design/methodology/approach The package is the design in the flip chip-chip scale package with bumping process and assembly. The package was put in reliability stress test that followed AEC-Q100 automotive criteria and recorded the IMC growing morphology. Findings The Cu6Sn5 intermetallic compound is the most sensitive to continuous heat which grows from 3 to 10 µm at high temperature storage 2,000 h testing, and the second is Cu3Sn IMC. Cu6Sn5 IMC will convert to Cu3Sn IMC at initial stage, and then Kirkendall void will be found at the interface of Cu and Cu3Sn IMC, which has quality concerning issue if the void’s density grows up. The first phase to form and grow into observable thickness for Ni and lead-free interface is Ni3Sn4 IMC, and the thickness has little relationship to the environmental stress, as no IMC thickness variation between TCT, uHAST and HTSL stress test. The more the Sn exists, the thicker Ni3Sn4 IMC will be derived from this experimental finding compare the Cu/Ni/SnAg cell and Ni/SnAg cell. Research limitations/implications The research found that FCCSP can pass automotive criteria that follow AEC-Q100, which give the confidence for upgrading the package type with higher efficiency and complexities of the pin design. Practical implications This result will impact to the future automotive package, how to choose the best package methodology and what is the way to do the package. The authors can understand the tolerance for the kind of flip chip package, and the bump structure is then applied for high-end technology. Originality/value The overall three kinds of bump structures, Cu/Ni/SnAg, Cu/SnAg and Ni/SnAg, were taken into consideration, and the IMC growing morphology had been recorded. Also, the IMC had changed during the environmental stress, and KV formation was reserved.

scholarly journals The external environment of birds as a factor of immunobiochemical conditions

2020 ◽  
Vol 9 (3) ◽  
pp. 152-157
Author(s):  
Rinat R. Fatkullin ◽  
Aikumis K. Saken
Keyword(s):  
Metabolic Disorders ◽  
Clinical Manifestations ◽  
The Body ◽  
Household Waste ◽  
Trophic Chain ◽  
Behavioral Strategies ◽  
The Public ◽  
Initial Stage ◽  
Highly Sensitive

Abnormal environmental factors contribute to advanced behavioral strategies in higher regulatory centers as well as to the assessment of possible morphofunctional and energy transformations in the body. Animals, especially birds, which are characterized by curiosity, are highly sensitive to the presence of environmental pollution, since they interact with elements of the environment and surroundings. Contamination of broiler products can also be caused by contaminated soil and dust, unknown sources of persistent heavy metals and organic pollutants that are unknown to the public, such as car wreckage, household waste, and so on. In general, adverse factors that regularly affect small details do not require significant changes in the body at the initial stage, mainly affect non-specific mechanisms that lead to long-term activation. The paper contains significant work based on the analysis of microbiogenic links in the trophic chain, but the formation of processes associated with metabolic disorders from the development of trace elements to clinical manifestations is still insufficiently studied, so it is difficult to diagnose and treat previously unknown animal diseases in veterinary practice.

scholarly journals Occurrence and spatial-temporal distribution of herbicide residues in the Ipojuca River sub-basin, Pernambuco, Brazil

2016 ◽  
Vol 20 (12) ◽  
pp. 1124-1128 ◽  
Author(s):  
Adson da S. G. Ferreira ◽  
Henrique C. M. P. da Silva ◽  
Hélio O. S. Rodrigues ◽  
Marileide Silva ◽  
Eden C. de Albuquerque Junior
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Temporal Distribution ◽  
Tandem Mass ◽  
Herbicide Residues ◽  
Ecological Changes ◽  
Biological Potential ◽  
Intensive Use

ABSTRACT The intensive use of pesticides to control pests in agriculture has exposed the environment and humans to a variety of risks. Among the crops with higher consumption of these compounds there is the sugarcane, developed in regions bordered by large watersheds. In this work, the occurrence of pesticides in the water of Ipojuca River was investigated in a 50 km range of its eastern portion, in a region noted for intense agroindustrial activity, especially by sugarcane cultivation, in the state of Pernambuco. Among fungicides, herbicides, insecticides and carbamates, 238 pesticides were investigated in the Ipojuca River using the technique of liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The study, conducted in the months of May, June, October and November 2012, detected the presence of Diuron and Ametryn herbicide residues in 100% of the water samples at concentrations from 0.01 to 1.4 μg L-1. The detection of these herbicides, even at residual concentrations, can lead to perceptible ecological changes in the long term, such as the reduction of the biological potential of animal and plant species.

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