scholarly journals Biophysics of Fish Sperm Flagellar Movement: Present Knowledge and Original Directions

10.5772/66863 ◽  
2017 ◽  
Author(s):  
Galina Prokopchuk ◽  
Jacky Cosson
Keyword(s):  
Present Knowledge ◽  
Fish Sperm

Fields of spatial research on urban areas in the context of organisational solutions to new forms of transportation

2018 ◽  
Vol 58 (1) ◽  
pp. 53-60
Author(s):  
Bartosz Czarnecki
Keyword(s):  
Urban Areas ◽  
Transportation System ◽  
Present Knowledge ◽  
Future Research ◽  
Use Of Self ◽  
Large Share ◽  
Main Achievement ◽  
Self Driving Cars

Abstract The paper discusses the spatial consequences of the widespread use of self-driving cars and the resulting changes in the structure of urban areas. Analysing present knowledge on the technology, functionality and future forms of organisation of mobility with this type of means of transportation, conclusions are presented concerning the expected changes in the organisation of space in urban areas. The main achievement of the investigation is an outline of the fields of future research on the spatial consequences of a transportation system with a large share of self-driving cars.

Saturated Hydraulic Conductivity of Clayey Tills and the Role of Fractures

1990 ◽  
Vol 21 (2) ◽  
pp. 119-132 ◽  
Author(s):  
Johnny Fredericia
Keyword(s):  
Hydraulic Conductivity ◽  
American Studies ◽  
Field Measurements ◽  
Present Knowledge ◽  
Saturated Hydraulic Conductivity ◽  
Field Observations ◽  
Laboratory Measurements ◽  
Vertical Hydraulic Conductivity ◽  
Data Field

The background for the present knowledge about hydraulic conductivity of clayey till in Denmark is summarized. The data show a difference of 1-2 orders of magnitude in the vertical hydraulic conductivity between values from laboratory measurements and field measurements. This difference is discussed and based on new data, field observations and comparison with North American studies, it is concluded to be primarily due to fractures in the till.

scholarly journals Antioxidants in Fish Sperm and the Potential Role of Melatonin

Antioxidants ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 36
Author(s):  
Francisca Félix ◽  
Catarina C. V. Oliveira ◽  
Elsa Cabrita
Keyword(s):  
Oxidative Stress ◽  
Fish Cell ◽  
Cell Protection ◽  
Factors Affecting ◽  
Fish Sperm ◽  
Scavenger Activity ◽  
Stress Damage ◽  
Novel Antioxidants ◽  
Aquaculture Production

In recent years, the effects of novel antioxidants have played an important role in the research focusing on fish cell protection. As food demand grows, aquaculture production becomes more intensive, and fish are more exposed to oxidative stress conditions, like high densities, temperature shifting, frequent fish handling and samplings, and prophylactic or disease treatments, which expose fish to a different environment. Particularly in reproduction, germ cells lose antioxidant capacity with spermatogenesis, as spermatozoa are more prone to oxidative stress. Antioxidants have been used in a variety of fish physiological problems including in reproduction and in the establishment of cryopreservation protocols. From the most used antioxidants to natural plant food and herbs, and endogenously produced antioxidants, like melatonin, a review of the literature available in terms of their effects on the protection of fish spermatozoa is presented here in a classified structure. Several direct and indirect approaches to improve gamete quality using antioxidants administration are mentioned (through feed supplementation or by adding in cryopreservation media), as well as factors affecting the efficiency of these molecules and their mechanisms of action. Special attention is given to the unclear melatonin pathway and its potential scavenger activity to prevent and counteract oxidative stress damage on fish spermatozoa.

Ornamental plants for the phytoremediation of heavy metals: Present knowledge and future perspectives

2021 ◽  
Vol 195 ◽  
pp. 110780
Author(s):  
Aqib Hassan Ali Khan ◽  
Amna Kiyani ◽  
Cyrus Raza Mirza ◽  
Tayyab Ashfaq Butt ◽  
Rocío Barros ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Ornamental Plants ◽  
Present Knowledge ◽  
Future Perspectives

scholarly journals Prenatal findings and postnatal follow-up of a midline dural sinus malformation

2021 ◽  
Vol 10 (4) ◽  
pp. 205846012110063
Author(s):  
Hana Shabana ◽  
Johannes Leidinger ◽  
Johan Wikström ◽  
Ove Axelsson
Keyword(s):  
Magnetic Resonance Imaging ◽  
Spontaneous Regression ◽  
Rare Condition ◽  
Present Knowledge ◽  
Magnetic Resonance Imaging Examination ◽  
Dural Sinus ◽  
Resonance Imaging ◽  
Prenatal Magnetic Resonance Imaging ◽  
Dural Sinus Malformation

Dural sinus malformation is a rare condition. We describe a prenatally detected case followed by repeated ultrasound scans and a prenatal magnetic resonance imaging examination. A substantial spontaneous regression was observed, which is associated with a favorable outcome. We believe that our observations, including a long postnatal follow-up, will add to the present knowledge of prenatally detected cases, and thus improve management of the pregnancies as well as our possibilities to counsel the parents-to-be.

scholarly journals Empirical α–β runout modelling of snow avalanches in the Catalan Pyrenees

2021 ◽  
pp. 1-12
Author(s):  
Pere Oller ◽  
Cristina Baeza ◽  
Glòria Furdada
Keyword(s):  
Comparative Analysis ◽  
Regression Model ◽  
Extreme Values ◽  
Multiple Linear Regression Model ◽  
Present Knowledge ◽  
Snow Avalanches ◽  
Independent Variables ◽  
Horizontal Length ◽  
Length And Area ◽  
Runout Modelling

Abstract A variation in the α−β model which is a regression model that allows a deterministic prediction of the extreme runout to be expected in a given path, was applied for calculating avalanche runout in the Catalan Pyrenees. Present knowledge of major avalanche activity in this region and current mapping tools were used. The model was derived using a dataset of 97 ‘extreme’ avalanches that occurred from the end of 19th century to the beginning of 21st century. A multiple linear regression model was obtained using three independent variables: inclination of the avalanche path, horizontal length and area of the starting zone, with a good fit of the function (R2 = 0.81). A larger starting zone increases the runout and a larger length of the path reduces the runout. The new updated equation predicts avalanche runout for a return period of ~100 years. To study which terrain variables explain the extreme values of the avalanche dataset, a comparative analysis of variables that influence a longer or shorter runout was performed. The most extreme avalanches were treated. The size of the avalanche path and the aspect of the starting zone showed certain association between avalanches with longer or shorter runouts.

American Institutional Studies: Present Knowledge and Past Trends

1971 ◽  
Vol 31 (1) ◽  
pp. 87-105 ◽  
Author(s):  
James H. Soltow
Keyword(s):  
Economic Theory ◽  
Economic History ◽  
Present Knowledge ◽  
Quarter Century ◽  
The Past

The production of economic history, like that in many fields of scholarly endeavor, increased sharply in the past quarter-century, compared to the rate of output in earlier eras. While the “new” economic history, with its emphasis on economic theory and measurement, has attracted considerable attention during the last decade, “traditional” economic history, written along institutional lines, has continued to be significant, both quantitatively (in terms of numbers of books and articles) and qualitatively (as assessed by contributions to our understanding of economic processes.)

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