scholarly journals Superfetation reduces the negative effects of pregnancy on the fast-start escape performance in live-bearing fish

2019 ◽  
Vol 286 (1916) ◽  
pp. 20192245 ◽  
Author(s):  
Mike Fleuren ◽  
Johan L. van Leeuwen ◽  
Bart J. A. Pollux
Keyword(s):  
Body Shape ◽  
Developmental Stages ◽  
Three Dimensional ◽  
Abdominal Distension ◽  
Locomotor Performance ◽  
Escape Performance ◽  
Negative Effects ◽  
Fast Start ◽  
High Predation ◽  
Different Levels

Superfetation, the ability to simultaneously carry multiple litters of different developmental stages in utero , is a reproductive strategy that evolved repeatedly in viviparous animal lineages. The evolution of superfetation is hypothesized to reduce the reproductive burden and, consequently, improve the locomotor performance of the female during pregnancy. Here, we apply new computer-vision-based techniques to study changes in body shape and three-dimensional fast-start escape performance during pregnancy in three live-bearing fishes (family Poeciliidae) that exhibit different levels of superfetation. We found that superfetation correlates with a reduced abdominal distension and a more slender female body shape just before parturition. We further found that body slenderness positively correlates with maximal speeds, curvature amplitude and curvature rate, implying that superfetation improves the fast-start escape performance. Collectively, our study suggests that superfetation may have evolved in performance-demanding (e.g. high flow or high predation) environments to reduce the locomotor cost of pregnancy.

scholarly journals Coasting in live-bearing fish: the drag penalty of being pregnant

2019 ◽  
Vol 16 (151) ◽  
pp. 20180714 ◽  
Author(s):  
Elsa M. Quicazan-Rubio ◽  
Johan L. van Leeuwen ◽  
Klaas van Manen ◽  
Mike Fleuren ◽  
Bart J. A. Pollux ◽  
...  
Keyword(s):  
Swimming Performance ◽  
Three Dimensional ◽  
Reproductive Investment ◽  
Body Volume ◽  
Negative Effects ◽  
Bending Performance ◽  
Body Drag ◽  
Wetted Area ◽  
Three Dimensional Models ◽  
Different Levels

Swimming performance of pregnant live-bearing fish is presumably constrained by the additional drag associated with the reproductive burden. Yet, it is still unclear how and to what extent the reproductive investment affects body drag of the females. We examined the effect of different levels of reproductive investment on body drag. The biggest measured increase in body volume due to pregnancy was about 43%, linked to a wetted area increase of about 16% and 69% for the frontal area. We printed three-dimensional models of live-bearing fish in a straight body posture representing different reproductive allocation (RA) levels. We measured the drag and visualized the flow around these models in a flow tunnel at different speeds. Drag grew in a power fashion with speed and exponentially with the increase of RA, thus drag penalty for becoming thicker was relatively low for low speeds compared to high ones. We show that the drag increase with increasing RA was most probably due to bigger regions of flow separation behind the enlarged belly. We suggest that the rising drag penalty with an increasing RA, possibly together with pregnancy-related negative effects on muscle- and abdominal bending performance, will reduce the maximum swimming speed.

Correlated Studies of Cellular Interactions Using TEM, Freeze Etching, and SEM

1974 ◽  
Vol 32 ◽  
pp. 320-321
Author(s):  
J. P. Revel
Keyword(s):  
Developmental Stages ◽  
Three Dimensional ◽  
Cell Movement ◽  
Cellular Interactions ◽  
Serial Sections ◽  
Cell Sheets ◽  
Freeze Etching ◽  
Early Developmental

Movement of individual cells or of cell sheets and complex patterns of folding play a prominent role in the early developmental stages of the embryo. Our understanding of these processes is based on three- dimensional reconstructions laboriously prepared from serial sections, and from autoradiographic and other studies. Many concepts have also evolved from extrapolation of investigations of cell movement carried out in vitro. The scanning electron microscope now allows us to examine some of these events in situ. It is possible to prepare dissections of embryos and even of tissues of adult animals which reveal existing relationships between various structures more readily than used to be possible vithout an SEM.

Energies and Electric Dipole Moments of the Bound Vibrational States of HN2+ and DN2+

2008 ◽  
Vol 73 (6-7) ◽  
pp. 873-897 ◽  
Author(s):  
Vladimír Špirko ◽  
Ota Bludský ◽  
Wolfgang P. Kraemer
Keyword(s):  
Dipole Moment ◽  
Nearest Neighbor ◽  
Energy Surface ◽  
Dipole Moments ◽  
Three Dimensional ◽  
Vibrational States ◽  
Spacing Distribution ◽  
Triatomic Molecules ◽  
Vibrational Levels ◽  
Different Levels

The adiabatic three-dimensional potential energy surface and the corresponding dipole moment surface describing the ground electronic state of HN2+ (Χ1Σ+) are calculated at different levels of ab initio theory. The calculations cover the entire bound part of the potential up to its lowest dissociation channel including the isomerization barrier. Energies of all bound vibrational and low-lying ro-vibrational levels are determined in a fully variational procedure using the Suttcliffe-Tennyson Hamiltonian for triatomic molecules. They are in close agreement with the available experimental numbers. From the dipole moment function effective dipoles and transition moments are obtained for all the calculated vibrational and ro-vibrational states. Statistical tools such as the density of states or the nearest-neighbor level spacing distribution (NNSD) are applied to describe and analyse general patterns and characteristics of the energy and dipole results calculated for the massively large number of states of the strongly bound HN2+ ion and its deuterated isotopomer.

3D Profile Variety Measurement of Pectoral Fin in Fish Fast Start

2011 ◽  
Vol 83 ◽  
pp. 280-284
Author(s):  
Ming Jiang ◽  
Shu Zhang ◽  
Xiao Yuan He
Keyword(s):  
Fourier Transform ◽  
High Speed ◽  
Kinetic Characteristic ◽  
Three Dimensional ◽  
Pectoral Fin ◽  
Fourier Transform Profilometry ◽  
Fast Start ◽  
Fringe Patterns ◽  
3D Information ◽  
3D Profile

Fast-starts are brief, sudden accelerations used by fish during predator-prey encounters. In this paper, a three-dimensional (3D) test and analysis method is critical to understand the function of the pectoral fin during maneuvers. An experiment method based on Fourier Transform Profilometry for 3D pectoral fin profile variety during fish maneuvers is proposed. This method was used in a carp fast-start during prey. Projecting the moiré fringes onto a carp pectoral fin it will produce the deformed fringe patterns contain 3D information. A high speed camera captures these time-sequence images. By Fourier transform, filter, inverse Fourier transform and unwrap these phase maps in 3D phase space, the complex pectoral fin profile variety were really reconstructed. The present study provides a new method to quantify the analysis of kinetic characteristic of the pectoral fin during maneuvers.

EFFECT OF ABRASIVE TYPE ON THE SURFACE ROUGHNESS AND MRR IN MAF OF AISI 304 STEEL

2021 ◽  
Author(s):  
MAHMUT ÇELIK ◽  
HAKAN GÜRÜN ◽  
ULAŞ ÇAYDAŞ
Keyword(s):  
Surface Roughness ◽  
Removal Rate ◽  
Three Dimensional ◽  
Steel Plates ◽  
304 Stainless Steel ◽  
Average Surface Roughness ◽  
Machining Time ◽  
Aisi 304 ◽  
Average Surface ◽  
Different Levels

In this study, the effects of experimental parameters on average surface roughness and material removal rate (MRR) were experimentally investigated by machining of AISI 304 stainless steel plates by magnetic abrasive finishing (MAF) method. In the study in which three different abrasive types were used (Al2O3, B4C, SiC), the abrasive grain size was changed in two different levels (50 and 80[Formula: see text][Formula: see text]m), while the machining time was changed in three different levels (30, 45, 60[Formula: see text]min). Surface roughness values of finished surfaces were measured by using three-dimensional (3D) optical surface profilometer and surface topographies were created. MRRs were measured with the help of precision scales. The abrasive particles’ condition before and after the MAF process was examined and compared using a scanning electron microscope. As a result of the study, the surface roughness values of plates were reduced from 0.106[Formula: see text][Formula: see text]m to 0.028[Formula: see text][Formula: see text]m. It was determined that the best parameters in terms of average surface roughness were 60[Formula: see text]min machining time with 50[Formula: see text][Formula: see text]m B4C abrasives, while the best result in terms of MRR was taken in 30[Formula: see text]min with 50[Formula: see text][Formula: see text]m SiC abrasives.

Metabolism-driven post-translational modifications of H3K9 in early bovine embryos

Reproduction ◽  
2021 ◽  
Vol 162 (3) ◽  
pp. 181-191
Author(s):  
Jessica Ispada ◽  
Aldcejam Martins da Fonseca Junior ◽  
Otávio Luiz Ramos Santos ◽  
Camila Bruna de Lima ◽  
Erika Cristina dos Santos ◽  
...  
Keyword(s):  
Metabolic Pathways ◽  
Developmental Stages ◽  
De Novo ◽  
Blastocyst Stage ◽  
Developmental Model ◽  
Bovine Embryos ◽  
Acetyl Coa ◽  
Post Translational Modifications ◽  
The Relationship ◽  
Different Levels

Metabolic and molecular profiles were reported as different for bovine embryos with distinct kinetics during the first cleavages. In this study, we used this same developmental model (fast vs slow) to determine if the relationship between metabolism and developmental kinetics affects the levels of acetylation or tri-methylation at histone H3 lysine 9 (H3K9ac and H3K9me3, respectively). Fast and slow developing embryos presented different levels of H3K9ac and H3K9me3 from the earliest stages of development (40 and 96 hpi) and up to the blastocyst stage. For H3K9me3, both groups of embryos presented a wave of demethylation and de novo methylation, although it was more pronounced in fast than slow embryos, resulting in blastocysts with higher levels of this mark. The H3K9ac reprogramming profile was distinct between kinetics groups. While slow embryos presented a wave of deacetylation, followed by an increase in this mark at the blastocyst stage, fast embryos reduced this mark throughout all the developmental stages studied. H3K9me3 differences corresponded to writer and eraser transcript levels, while H3K9ac patterns were explained by metabolism-related gene expression. To verify if metabolic differences could alter levels of H3K9ac, embryos were cultured with sodium-iodoacetate (IA) or dichloroacetate (DCA) to disrupt the glycolytic pathway or increase acetyl-CoA production, respectively. IA reduced H3K9ac while DCA increased H3K9ac in blastocysts. Concluding, H3K9me3 and H3K9ac patterns differ between embryos with different kinetics, the second one explained by metabolic pathways involved in acetyl-CoA production. So far, this is the first study demonstrating a relationship between metabolic differences and histone post-translational modifications in bovine embryos.

scholarly journals Preclinical Ultrasound-Guided Photoacoustic Imaging of the Placenta in Normal and Pathologic Pregnancy

2018 ◽  
Vol 17 ◽  
pp. 153601211880272 ◽  
Author(s):  
Liliya M. Yamaleyeva ◽  
K. Bridget Brosnihan ◽  
Lane M. Smith ◽  
Yao Sun
Keyword(s):  
Oxygen Saturation ◽  
Early Identification ◽  
Photoacoustic Imaging ◽  
Three Dimensional ◽  
Normal Pregnancy ◽  
Preclinical Study ◽  
Ultrasound Guided ◽  
3 Dimensional ◽  
Sensitive Tool ◽  
Different Levels

Placental oxygenation varies throughout pregnancy. The detection of early changes in placental oxygenation as pregnancy progresses is important for early identification of preeclampsia or other complications. This invited commentary discusses a recent preclinical study on the application of 3-dimensional photoacoustic imaging (PAI) for assessment of regional variations in placental oxygenation and longitudinal analysis of differences in placental oxygenation throughout normal pregnancy and pregnancy associated with hypertension or placental insufficiency in mice. Three-dimensional PAI more accurately reflects oxygen saturation, hemoglobin concentrations, and changes in oxygen saturation in whole placenta compared to 2-dimensional imaging. These studies suggest that PAI is a sensitive tool to detect different levels of oxygen saturation in the placental and fetal vasculature in pathologic and normal pregnancy in mice.

scholarly journals Effectiveness of Three Post-Harvest Rehabilitation Treatments for Runoff and Sediment Reduction on Skid Trails in the Hyrcanian Forests

2020 ◽  
Vol 41 (2) ◽  
pp. 309-324
Author(s):  
Meghdad Jourgholami ◽  
Masoumeh Ahmadi ◽  
Farzam Tavankar ◽  
Rodolfo Picchio
Keyword(s):  
Leaf Litter ◽  
Sediment Yield ◽  
Rainfall Intensity ◽  
Regression Equations ◽  
Negative Effects ◽  
Diverse Range ◽  
Straw Mulch ◽  
The Impact ◽  
Different Levels ◽  
Runoff And Sediment Yield

Ground-based skidding operations can lead to soil compaction and displacement, which could cause negative effects on forest soil. Hence, some efforts such as forestry best management practices (BMPs) must be implemented in the prone area to mitigate these possible impacts. Several materials and treatments have been adopted to suppress these adverse effects by increasing the ground cover. However, the effects of mulch treatments on runoff and sediment yield are inconclusive with a diverse range of effectiveness. For these reasons, in this research mulch treatments were tested as to determine how the application of organic mulch amendments such as straw and leaf litter and contour-felled logs would alleviate the runoff and sediment yield on machine operating trails and ensure successful hillslope stabilization. The aims of the study were to analyse and compare the effectiveness of leaf litter (LM) and straw mulch (SM) rate and different distances of contour-felled logs (CFL) to mitigate the runoff and sediment yield, and examine the impact of rainfall intensity on effectiveness of litter mulch, straw mulch, and contour-felled logs. Totally, 30 bounded runoff plots in the machine operating trails and four treatments including litter mulch (LMR1: 0.62, LMR2: 1.24, and LMR3: 1.86 kg m-2), straw mulch (SMR1: 0.45, SMR2: 0.92, and SMR3: 1.34 kg m-2), contour-felled logs (CFL10: 10, CFL20: 20, and CFL30: 30 m), and untreated area were established in triplicate with 4 m width and 100 m length. During the study period, the runoff and sediment yield in the untreated trails (U) were 2.36 mm and 11.84 g m-2. Straw (from 41.5 to 60.6%) and litter mulch (from 38.1 to 55.1%), and contour-felled logs treatments (from 70.8 to 88.1%) significantly decreased the runoff, compared to U treatment. Results show that mulch treatments with three different levels of Litter Mulch Rate, LMR1, LMR2, and LMR3 decreased mean sediment by 46.6, 64.0 and 71.8%, in the treatments with three different levels of Straw Mulch Rate, SMR1, SMR2, and SMR3 decreased mean sediment by 42.9, 62.1, and 69.9%, and in the treatments with three different distances of Contour-Felled Logs, CFL10, CFL20, and CFL30 decreased mean sediment by 90.6, 94.7 and 88.3% comparing to U, respectively. The relationships of the runoff and sediment responses to increasing mulching rate of litter and straw followed as negative logarithmic curves, but the decreasing-increasing trends were observed in runoff and sediment yield as the distance between contour-felled logs increased from 10 to 30 m. Polynomial regression equations were developed for predicting the runoff and sediment yield as a function of the application rate of litter and straw mulch and the distance between contour-felled logs, and rainfall intensity. We concluded that contour-felled logs treatment was more effective than both litter and straw mulch to mitigate the runoff, runoff coefficient, and sediment yield on machine operating trails. As a management measure, it could be possible to propose that the contour-felled logs with a distance of 20 m be prescribed to protect the machine operating trails from the negative effects of surface waterflow.

scholarly journals Environment, tourism and planning

2003 ◽  
Vol 83 (2) ◽  
pp. 19-30 ◽  
Author(s):  
Stevan Stankovic
Keyword(s):  
Tourism Development ◽  
Modern Society ◽  
International Tourism ◽  
Negative Effects ◽  
Tourism Planning ◽  
Nature Protection ◽  
Active Protection ◽  
Foreign Tourism ◽  
Different Levels ◽  
Negative Phenomena

One of the characteristics of modern society are more massive tourist trends. Tourists overcame all parts of our planet and provoked line of positive and negative phenomena and processes. Positive dominate negative and that?s the reason why many countries develop domicile and foreign tourism. Environment and tourism perform indivisible totality. Contemporary tourism demands important areas of original or well protected environment, because only on this areas can be develops planned and brings economic and social advantages to domicile population (receptive) and to tourists (initiative). Science and practice for needs of tourism considers line of positive relations toward environment, because some of her elements are special tourist values. For need of tourism is underlines need of acceptation principles of active protection environment, because it is always better to plan, than to reclaim negative effects. In work which treats environment, modern tourism and planning, is appeared to scope of international tourism in world and dynamics of tourism development in a last six decades. It was special emphasized relations between tourism and nature, because in many countries offer of natural tourist values is more massive than offer of monuments. It is a word about need of nature protection for tourism, because nature is a real tourist value only when she is authentic or well protected. In second part it was analyzed importance of tourism planning on different levels, considering local and national traits in areas favorable for tourism development.

scholarly journals Photosynthetic performance of young maize (Zea mays L.) plants exposed to chilling stress can be improved by the application of protein hydrolysates

2019 ◽  
Vol 72 (2) ◽  
Author(s):  
Rositsa Cholakova-Bimbalova ◽  
Veselin Petrov ◽  
Andon Vassilev
Keyword(s):  
Developmental Stages ◽  
Protein Hydrolysate ◽  
Leaf Gas Exchange ◽  
Chilling Stress ◽  
Photosynthetic Pigment ◽  
Photosynthetic Performance ◽  
Protein Hydrolysates ◽  
Negative Effects ◽  
Climate Conditions ◽  
Maize Plants

Biostimulants offer a novel approach for the regulation of crucial physiological processes in plants. Recently, it has been observed that the application of biostimulants on both seeds and plants may ameliorate to some extent the negative effects of abiotic stresses such as drought, heat, salinity, and others. In the climate conditions of Bulgaria, the early developmental stages of warm climate crops, like maize, often occur under suboptimal temperatures. Although the mitigation of abiotic stress is perhaps the most frequently cited benefit of biostimulant formulations, little is known about their influence on chilling-stressed plants. The aim of our study was to evaluate the effects of a biostimulant from the group of protein hydrolysates on both the growth and the photosynthetic performance of chilling-exposed young maize plants grown in controlled environment. Here, we report that application of a protein hydrolysate increased the performance of chilled maize plants, as demonstrated by leaf gas exchange, photosynthetic pigment content, and chlorophyll fluorescence, but did not affect their growth. Nevertheless, based on the better preserved photosynthetic performance of the biostimulant-treated maize plants exposed to chilling, we assume that under subsequent favorable conditions their growth would recover more quickly as compared to the untreated ones.

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