uniform density
Recently Published Documents


TOTAL DOCUMENTS

453
(FIVE YEARS 74)

H-INDEX

33
(FIVE YEARS 4)

Heredity ◽  
2021 ◽  
Author(s):  
Christina Steinecke ◽  
Courtney E. Gorman ◽  
Marc Stift ◽  
Marcel E. Dorken

AbstractThe transition to self-compatibility from self-incompatibility is often associated with high rates of self-fertilization, which can restrict gene flow among populations and cause reproductive isolation of self-compatible (SC) lineages. Secondary contact between SC and self-incompatible (SI) lineages might re-establish gene flow if SC lineages remain capable of outcrossing. By contrast, intrinsic features of SC plants that reinforce high rates of self-fertilization could maintain evolutionary divergence between lineages. Arabidopsis lyrata subsp. lyrata is characterized by multiple origins of self-compatibility and high rates of self-fertilization in SC-dominated populations. It is unclear whether these high rates of selfing by SC plants have intrinsic or extrinsic causes. We estimated outcrossing rates and examined patterns of pollinator movement for 38 SC and 40 SI maternal parents sampled from an admixed array of 1509 plants sourced from six SC and six SI populations grown under uniform density. Although plants from SI populations had higher outcrossing rates (mean tm = 0.78 ± 0.05 SE) than plants from SC populations (mean tm = 0.56 ± 0.06 SE), outcrossing rates among SC plants were substantially higher than previous estimates from natural populations. Patterns of pollinator movement appeared to contribute to lower outcrossing rates for SC plants; we estimated that 40% of floral visits were geitonogamous (between flowers of the same plant). The relatively high rates of outcrossing for SC plants under standardized conditions indicate that selfing rates in natural SC populations of A. lyrata are facultative and driven by extrinsic features of A. lyrata, including patterns of pollinator movement.


2021 ◽  
Vol 55 (9-10) ◽  
pp. 951-959
Author(s):  
AGATHA E. R. PRADO GÁRATE ◽  
◽  
FERNANDO ESTEBAN FELISSIA ◽  
MARIA CRISTINA AREA ◽  
TERESA SUIREZS ◽  
...  

High-value products can be obtained from non-traditional lignocellulosic resources, such as bamboo, taking full advantage of these materials through efficient, low-cost and low-pollution fractionation processes. This work aims to analyze the physical, chemical, and morphological differences between two bamboo species as a rapidly growing resource of great regional interest – Guadua trinii and Guadua angustifolia. Both samples were characterized in terms of basic density, morphological characteristics, and chemical composition. This work shows that G. trinii has a significantly denser woody structure, with a uniform density at the sampled culm height. The internal structure consists of a parenchyma matrix and vascular bundles composed of parenchyma cells and fiber bundles. G. angustifolia has significantly longer fibers. Chemical characterization showed differences between the carbohydrate and lignin contents. The results of this work are critical to know the potential of both bamboo species as a source of high-value products in the bamboo biorefinery framework.


2021 ◽  
Vol 939 (1) ◽  
pp. 012063
Author(s):  
Terwase Wuave

Abstract The constituents of leachate generation and migration in ministry of agriculture nursery open dumpsite in Jos Plateau were determined. Leachate extraction from solid waste (SW) was carried out. Test dumpsite soil with different elevations. Elevations were with uniform density. Representative solid waste dumpsite soil sample were collected from one dumpsite. The collected SW soil subjected to column experimental test, results showed physicochemical parameters (pH, TSS,TDS and EC) range of descriptive value in terms of histogram values of 5.66 – 8.23(1.0m to 1.5m depth) pH, 90.65 – 1125.96mg/l (0.5 to 2.0m depth) TSS, 17.78 – 156mg/l (1.5 to 0.5m depth) TDS, 9.02 – 80.01 us/cm and principal component summary analysis. The histogram and principal component summary values increase. Alkalinity has highest concentration, followed by hardness which has least, BOD5 has lower values, followed by COD which has higher value, Cl−increasing, S04 2-, N03 values increases, P04 in waste decreases with increase time and depth. The Na+, increasing K+ second to Na+, increases, Mg2+ and Ca2+ in MSW increases as time and depth proceed. The results of Cu, Fe, Cd and Pb in histogram had moderate to high values. All were examined for physicochemical, alkalinity and hardness, BOD5, COD, anions, cations and heavy metals to study the seasonal variation of significant parameters. The results from the leachate analysis were used as a tool to identify the processes and mechanisms affecting the soil and water chemistry from the study area.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Xu Wang ◽  
Aiya Zhu ◽  
Hongying Cai ◽  
Baixue Liu ◽  
Gang Xie ◽  
...  

Abstract Background Cystic echinococcosis (CE), caused by the larval stage of the complex Echinococcus granulosus sensu lato (s.l.), is a zoonotic parasitic disease with a high social burden in China. E. ortleppi is a species (formerly genotype 5 of E. granulosus s.l.) with unique epidemic areas (tropical areas), transmission patterns (mainly cattle origin), and pathological characteristics (large and small hook lengths) compared to other species that cause CE. A 19-year-old female patient in an area with no history of echinococcosis in Guizhou Province, China, was diagnosed with E. ortleppi infection in 2019. This study is to understand the source of this human E.ortleppi infection. Methods We performed computer tomography (CT) scans, surgical operation, morphological sectioning, molecular diagnosis, phylogenetic analyses, and epidemiological investigation in Anshun City, Guizhou Province, China in 2019. Results The patient presented with intermittent distension and pain in the upper abdomen without other abnormal symptoms. Routine blood examination results were normal. However, abdominal CT revealed a fertile cyst with a diameter of approximately 8 cm, uniform density, and a clear boundary, but without an evident cyst wall in the right lobe of the liver. The cyst was fertile, and phylogenetic analyses revealed that the isolates represented a new E. ortleppi genus haplotype. A result of 10‒14 years incubation period with indigenous infection was considered available for the case through the epidemiological survey. Conclusions CE due to E. ortleppi infection can be confused with other diseases causing liver cysts, resulting in misdiagnosis. A transmission chain of E. ortleppi may exist or existed in the past in the previously considered non-endemic areas of echinococcosis in southwestern China. Graphic abstract


2021 ◽  
Vol 8 (2) ◽  
pp. 159-171
Author(s):  
Teguh Darmawan ◽  
Adik Bahanawan ◽  
Danang S. Adi ◽  
Wahyu Dwianto ◽  
Naresworo Nugroho

Removing the outer part of bamboo for manufacturing flat bamboo lamination has disadvantage on the density of the product. The purpose of this experiment was to investigate the fixation of compressed bamboo from curved cross-section slats. The compression of bamboo slats using densification technique was aimed for uniform density. Furthermore, steam treatments were conducted to fix the deformation. The compressed bamboo slats revealed that the density of the samples at the bottom parts increased from 0.40–0.56 g/cm3 to 0.89–1.05 g/cm3 after pressing with a compression level between 46.98–63.97%, while the samples in the middle parts increased from 0.70–0.83 g/cm3 to 1.02–1.18 g/cm3 with the compression level of 32.92–41.50%. These results were slightly higher than that of the upper parts, which was between 0.91–0.98 g/cm3. The recovery of set decreased and the weight loss increased with  increasing  temperature and steam treatment time. Fixation of compressive deformation could be achieved at 160°C within 60 minutes. The bottom parts of samples experienced a slightly greater weight loss compared to the middle parts, i.e. 8.38% and 7.49%, respectively. The anatomical structure of bamboo tended to deform during densification process. Furthermore, the steam treatments affected  the colour of densified bamboo which became darker. From this experiment, it can be concluded that the manufacture of laminated bamboo from bamboo slats can be uniformed in strength by equalizing the density at the bottom and middle with the upper parts through the densification technique. However, further research should be conducted to know the delamination and shear strength of the bamboo lamination.


Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6521
Author(s):  
Yeabsra Mekdim Hailu ◽  
Aamer Nazir ◽  
Shang-Chih Lin ◽  
Jeng-Ywan Jeng

Functionally graded lattice structures have attracted much attention in engineering due to their excellent mechanical performance resulting from their optimized and application-specific properties. These structures are inspired by nature and are important for a lightweight yet efficient and optimal functionality. They have enhanced mechanical properties over the uniform density counterparts because of their graded design, making them preferable for many applications. Several studies were carried out to investigate the mechanical properties of graded density lattice structures subjected to different types of loadings mainly related to tensile, compression, and fatigue responses. In applications related to biomedical, automotive, and aerospace sectors, dynamic bending and rotational stresses are critical load components. Therefore, the study of torsional properties of functionally gradient lattice structures will contribute to a better implementation of lattice structures in several sectors. In this study, several functionally gradient triply periodic minimal surfaces structures and strut-based lattice structures were designed in cylindrical shapes having 40% relative density. The HP Multi Jet Fusion 4200 3D printer was used to fabricate all specimens for the experimental study. A torsional experiment until the failure of each structure was conducted to investigate properties of the lattice structures such as torsional stiffness, energy absorption, and failure characteristics. The results showed that the stiffness and energy absorption of structures can be improved by an effective material distribution that corresponds to the stress concentration due to torsional load. The TPMS based functionally gradient design showed a 35% increase in torsional stiffness and 15% increase in the ultimate shear strength compared to their uniform counterparts. In addition, results also revealed that an effective material distribution affects the failure mechanism of the lattice structures and delays the plastic deformation, increasing their resistance to torsional loads.


Author(s):  
Claudia M. Chanu ◽  
Basel Jayyusi ◽  
Raymond G. Mclenaghan

The geometric theory of additive separation of variables is applied to the search for multiplicative separated solutions of the bi-Helmholtz equation. It is shown that the equation does not admit regular separation in any coordinate system in any pseudo-Riemannian space. The equation is studied in the four coordinate systems in the Euclidean plane where the Helmholtz equation and hence the bi-Helmholtz equation is separable. It is shown that the bi-Helmoltz equation admits non-trivial non-regular separation in both Cartesian and polar coordinates, while it possesses only trivial separability in parabolic and elliptic–hyperbolic coordinates. The results are applied to the study of small vibrations of a thin solid circular plate of uniform density which is governed by the bi-Helmholtz equation.


2021 ◽  
Vol 13 (19) ◽  
pp. 3844
Author(s):  
Mengchi Ai ◽  
Zhixin Li ◽  
Jie Shan

Indoor structures are composed of ceilings, walls and floors that need to be modeled for a variety of applications. This paper proposes an approach to reconstructing models of indoor structures in complex environments. First, semantic pre-processing, including segmentation and occlusion construction, is applied to segment the input point clouds to generate semantic patches of structural primitives with uniform density. Then, a primitives extraction method with detected boundary is introduced to approximate both the mathematical surface and the boundary of the patches. Finally, a constraint-based model reconstruction is applied to achieve the final topologically consistent structural model. Under this framework, both the geometric and structural constraints are considered in a holistic manner to assure topologic regularity. Experiments were carried out with both synthetic and real-world datasets. The accuracy of the proposed method achieved an overall reconstruction quality of approximately 4.60 cm of root mean square error (RMSE) and 94.10% Intersection over Union (IoU) of the input point cloud. The development can be applied for structural reconstruction of various complex indoor environments.


2021 ◽  
Author(s):  
Xinyi Chen ◽  
Pingding Kuang ◽  
Qiaoling Ding ◽  
Zijian Wang ◽  
Biao Jiang

Abstract Purpose This study aimed to report the computed tomography (CT) and magnetic resonance imaging (MRI)characteristics of primary Non-Hodgkin's Lymphoma (NHL) of the larynx. Materials and methods The radiographic examinations of five patients (2 men, 3 women; median age, 68years) with histopathologically proven NHL of the larynx were retrospectively reviewed. CT and MRI images were analyzed qualitatively (Tumor distribution, Local tumor invasion, Tumor appearance, Cervical lymphadenopathy of NHL). Results CT and MRI images showed no obvious signs of vascular and laryngeal cartilage invasion. Three cases (1 MALT, 2 diffuse large B-cell lymphomas (DLBCL)) were centered in the supraglottic region involved the glottis (3/3) and subglottic (1/3). Two cases (MALT) were centered in the glottis involved the subglottic. The laryngeal tumors involved the true cords (5 cases), aryepiglottic folds (3 cases), ventricles and false cords (3 cases), anterior commissure (2 cases). On MRI (4 cases), all NHL presenting as homogeneous intermediate T1-weighted, heterogeneous slightly high T2-weighted mass with homogeneous moderate to evident enhancement. The mucosa with more obvious enhancement and smooth surface could be seen. On CT (1 plain and 3 contrast-enhanced), all tumors were homogeneous moderate density, and no necrosis or calcifications were seen. Lymphadenopathy was presented in two patients of DLBCL without necrosis. Conclusions On MRI or CT, when the laryngeal mass is located under the mucosa with uniform density or signal intensity, smooth surface, moderate to obvious homogeneous enhancement without cystic, necrosis, calcification and cartilage destruction, the radiologist should consider that it is likely to be NHL, especially when the mass spreads upwards to the oropharynx, nasopharynx and Webster's lymphoid ring. Further studies however are needed to confirm our findings obtained in a limited number of patients.


2021 ◽  
Vol 926 ◽  
Author(s):  
Marta Magnani ◽  
Stefano Musacchio ◽  
Guido Boffetta

We investigate the dynamics of a dilute suspension of small, heavy particles superposed on a reservoir of still, pure fluid. The study is performed by means of numerical simulations of the Saffman model for a dilute particle suspension (Saffman, J. Fluid Mech., vol. 13, issue 1, 1962, pp. 120–128). In the presence of gravity forces, the interface between the two phases is unstable and evolves in a turbulent mixing layer which broadens in time. In the case of negligible particle inertia, the particle-laden phase behaves as a denser fluid, and the dynamics of the system recovers to that of the incompressible Rayleigh–Taylor set-up. Conversely, particles with large inertia affect the evolution of turbulent flow, delaying the development of turbulent mixing and breaking the up–down symmetry within the mixing layer. The inertial dynamics also leads to particle clustering, characterised by regions with higher particle density than the initial uniform density, and by the increase of the local Atwood number.


Sign in / Sign up

Export Citation Format

Share Document