Incidence, causes and consequences of pregnancy failure in viviparous lizards: implications for research and conservation settings

2010 ◽  
Vol 22 (5) ◽  
pp. 761 ◽  
Author(s):  
Kelly M. Hare ◽  
Alison Cree
Keyword(s):  
Reproductive Output ◽  
Uv Light ◽  
Hormonal Changes ◽  
Successful Development ◽  
Pregnancy Failure ◽  
Thermal Environments ◽  
Research Areas ◽  
High Conservation ◽  
Experimental Group ◽  
Different Levels

Research on the causes of pregnancy failure in vertebrates has historically been mammal-focussed. However, live-birth (viviparity) has evolved multiple times, and is present in all other vertebrate taxa except Aves and Agnatha. Viviparous lizards (O. Squamata, excluding snakes and amphisbaenians) provide a valuable experimental group when studying major evolutionary events and some are also species of high conservation value. Consequently, both researchers and herpetoculturists often require high reproductive output from captive-held lizards. We reviewed the literature to determine potential or known causes of pregnancy failure for captive lizards. Pregnancy success across species averages ~86%, but varies extensively and does not appear to be related to embryonic stage when brought into captivity or level of placentation. Causes of pregnancy failure also vary among species, but correct thermal environments are vital to success, and providing adequate nutrition before vitellogenesis increases the number of viable offspring. A coordinated sequence of hormonal changes involving both pro-pregnancy and pro-labour factors is important for successful pregnancies, although uncertainty remains around the maternal concentrations of corticosterone that allow successful development. Several research areas commonly studied in mammals have yet to be explored or fully addressed in pregnant lizards, including impacts of toxins, parasites, UV light and nutritional quality. As viviparity has evolved over 100 times in lizards, and many different levels of placentation exist, pregnant lizards provide valuable models for studies in ecology and evolution and offer a useful comparison for studies on other viviparous vertebrates.

scholarly journals INTERDISCIPLINARY SYSTEM ARCHITECTURES IN AGILE MODULAR DEVELOPMENT IN THE PRODUCT GENERATION DEVELOPMENT MODEL USING THE EXAMPLE OF A MACHINE TOOL MANUFACTURER

2021 ◽  
Vol 1 ◽  
pp. 1897-1906
Author(s):  
Clemens Birk ◽  
Marc Zuefle ◽  
Albert Albers ◽  
Nikola Bursac ◽  
Dieter Krause
Keyword(s):  
Product Development ◽  
Development Model ◽  
Modular System ◽  
Successful Development ◽  
Development Environment ◽  
System Architectures ◽  
Product Generation ◽  
Mechanical Products ◽  
Machine Manufacturer ◽  
Different Levels

AbstractThis paper considers the orientation of product development structures towards interdisciplinary system architectures using the example of a tool machine manufacturer. Due to the change from simple mechanical products to extensively designed systems, whose successful development requires the integration of all disciplines involved, it is analyzed which requirements there are for these interdisciplinary system architectures in today's development environment. In addition, it is validated on the basis of the investigation environment that interdisciplinary system structures are necessary for the development on the different levels of the system view. In doing so, the investigation environment addresses the concept of extracting customer-relevant features (systems) from a physical-tailored modular system (supersystem) in order to develop and test them autonomously, as well as to transfer them to the entire product range in a standardized manner. The elaboration identifies basic requirements for the development of a knowledge base in interdisciplinary system structures and places them into the context of an agile modular kit development.

scholarly journals Flexible and Transparent Polymer-Based Optical Humidity Sensor

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3674
Author(s):  
Katerina Lazarova ◽  
Silvia Bozhilova ◽  
Sijka Ivanova ◽  
Darinka Christova ◽  
Tsvetanka Babeva
Keyword(s):  
Humidity Sensor ◽  
Amphiphilic Copolymer ◽  
Poly Vinyl Alcohol ◽  
Optical Monitoring ◽  
Optical Contrast ◽  
Successful Development ◽  
Flexible Sensor ◽  
Surface Profiling ◽  
Humidity Range ◽  
Different Levels

Thin spin-coated polymer films of amphiphilic copolymer obtained by partial acetalization of poly (vinyl alcohol) are used as humidity-sensitive media. They are deposited on polymer substrate (PET) in order to obtain a flexible humidity sensor. Pre-metallization of substrate is implemented for increasing the optical contrast of the sensor, thus improving the sensitivity. The morphology of the sensors is studied by surface profiling, while the transparency of the sensor is controlled by transmittance measurements. The sensing behavior is evaluated through monitoring of transmittance values at different levels of relative humidity gradually changing in the range 5–95% and the influence of up to 1000 bending deformations is estimated by determining the hysteresis and sensitivity of the flexible sensor after each set of deformations. The successful development of a flexible sensor for optical monitoring of humidity in a wide humidity range is demonstrated and discussed.

scholarly journals ІНТЕНСИВНІСТЬ ПРОЦЕСІВ ПОЛ ТА АКТИВНІСТЬ СИСТЕМИ АНТИОКСИДАНТНОГО ЗАХИСТУ У КРОВІ КОРОПІВ ЗА ДІЇ РІЗНОГО РІВНЯ ВІТАМІНУ Е І СЕЛЕНУ В РАЦІОНІ

2016 ◽  
Vol 18 (3(71)) ◽  
pp. 201-204
Author(s):  
S.V. Yurchak ◽  
O.V. Derenj ◽  
O.I. Vishchur ◽  
Yu.M. Zabytivskyi
Keyword(s):  
Lipid Peroxidation ◽  
Vitamin E ◽  
Control Group ◽  
Fish Feed ◽  
Dose Dependent Decrease ◽  
Fat Soluble Vitamins ◽  
And Control ◽  
Dose Dependent ◽  
Experimental Group ◽  
Different Levels

The article consist data about effect of different levels of vitamin E and selenium in the diet of carps during their growing and also informationabout the influence on processes of lipid peroxidation and activity of antioxidant protection in their body.The experiment conducted in three experimental ponds. After wintering there were placed four ears mature females and males carp, six individuals in each group. Supplements of vitamin E administered at a rate of 25 mg/kg and drug «Sel–Plex» the rate of selenium – 0.3 mg/kg were added to further basic diet(BD) of female and male carp first experimental group (EG1). The second experimental group (EG2) received (BD) and vitamin E supplements in an amount of 75 mg / kg, and just as in EG1 – selenium – 0.3 mg/kg of feed.The control group received fish feed without additives vitamins and minerals.Feeding lasted for 30 days, due to the physiological needs of the fish feed. After spawning in fish of research and control group swere taken blood samples for biochemical research.The study led to a dose–dependent decrease (p < 0.01 – 0.001) content of TBA–active products and hydroperoxidase of lipids, but did not significantly effect onsuperoxide dismutase and glutathione peroxidase activity of blood So, the reduction of lipid peroxidation products in the carp’s blood of experimental groups probably was caused by the growth of non–enzymatic level, which is associated with fat–soluble vitamins. 

scholarly journals Construction, Detection, and Interpretation of Crime Patterns over Space and Time

2020 ◽  
Vol 9 (6) ◽  
pp. 339
Author(s):  
Zengli Wang ◽  
Hong Zhang
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Empirical Studies ◽  
Prevention Strategies ◽  
Crime Patterns ◽  
Risk Levels ◽  
Research Areas ◽  
Research Objects ◽  
Crime Risk ◽  
Different Levels

Empirical studies have focused on investigating the interactive relationships between crime pairs. However, many other types of crime patterns have not been extensively investigated. In this paper, we introduce three basic crime patterns in four combinations. Based on graph theory, the subgraphs for each pattern were constructed and analyzed using criminology theories. A Monte Carlo simulation was conducted to examine the significance of these patterns. Crime patterns were statistically significant and generated different levels of crime risk. Compared to the classical patterns, combined patterns create much higher risk levels. Among these patterns, “co-occurrence, repeat, and shift” generated the highest level of crime risk, while “repeat” generated much lower levels of crime risk. “Co-occurrence and shift” and “repeat and shift” showed undulated risk levels, while others showed a continuous decrease. These results outline the importance of proposed crime patterns and call for differentiated crime prevention strategies. This method can be extended to other research areas that use point events as research objects.

scholarly journals First- and second-order sociality determine survival and reproduction in cooperative cichlids

2015 ◽  
Vol 282 (1819) ◽  
pp. 20151971 ◽  
Author(s):  
Arne Jungwirth ◽  
Michael Taborsky
Keyword(s):  
Social Organization ◽  
Group Size ◽  
Reproductive Output ◽  
Local Population ◽  
Cichlid Fish ◽  
Evolution Of Cooperation ◽  
Large Group ◽  
Indirect Fitness ◽  
Fitness Benefits ◽  
Different Levels

Cooperative breeders serve as a model to study the evolution of cooperation, where costs and benefits of helping are typically scrutinized at the level of group membership. However, cooperation is often observed in multi-level social organizations involving interactions among individuals at various levels. Here, we argue that a full understanding of the adaptive value of cooperation and the evolution of complex social organization requires identifying the effect of different levels of social organization on direct and indirect fitness components. Our long-term field data show that in the cooperatively breeding, colonial cichlid fish Neolamprologus pulcher , both large group size and high colony density significantly raised group persistence. Neither group size nor density affected survival at the individual level, but they had interactive effects on reproductive output; large group size raised productivity when local population density was low, whereas in contrast, small groups were more productive at high densities. Fitness estimates of individually marked fish revealed indirect fitness benefits associated with staying in large groups. Inclusive fitness, however, was not significantly affected by group size, because the direct fitness component was not increased in larger groups. Together, our findings highlight that the reproductive output of groups may be affected in opposite directions by different levels of sociality, and that complex forms of sociality and costly cooperation may evolve in the absence of large indirect fitness benefits and the influence of kin selection.

scholarly journals Ecologically relevant thermal fluctuations enhance offspring fitness: biological and methodological implications for studies of thermal developmental plasticity

2020 ◽  
Author(s):  
Joshua M. Hall ◽  
Daniel A. Warner
Keyword(s):  
Natural Variation ◽  
Developmental Plasticity ◽  
Methodological Approach ◽  
Thermal Fluctuations ◽  
Thermal Ecology ◽  
Laboratory Studies ◽  
Successful Development ◽  
Natural Systems ◽  
Thermal Environments ◽  
Underlying Mechanisms

ABSTRACTNatural thermal environments are notably complex and challenging to mimic in controlled studies. Consequently, our understanding of the ecological relevance and underlying mechanisms of organismal responses to thermal environments is often limited. For example, studies of thermal developmental plasticity have provided key insights into the ecological consequences of temperature variation, but most laboratory studies use treatments that do not reflect natural thermal regimes. While controlling other important factors, we compared the effects of naturally fluctuating temperatures to commonly used laboratory regimes on development of lizard embryos and offspring phenotypes and survival. We incubated eggs in 4 treatments – 3 that followed procedures commonly used in the literature, and one that precisely mimicked naturally fluctuating nest temperatures. To explore context-dependent effects, we replicated these treatments across two seasonal regimes: relatively cool temperatures from nests constructed early in the season and warm temperatures from late-season nests. We show that natural thermal fluctuations have a relatively small effect on developmental variables but enhance hatchling performance and survival at cooler temperatures. Thus, natural thermal fluctuations are important for successful development and simpler approximations (e.g. repeated sine waves, constant temperatures) may poorly reflect natural systems under some conditions. Thus, the benefits of precisely replicating real-world temperatures in controlled studies may outweigh logistical costs. Although patterns might vary according to study system and research goals, our methodological approach demonstrates the importance of incorporating natural variation into controlled studies and provides biologists interested in thermal ecology with a framework for validating the effectiveness of commonly used methods.

scholarly journals Mitosis Inhibitors Induce Massive Accumulation of Phytoene in the Microalga Dunaliella salina

Marine Drugs ◽  
2021 ◽  
Vol 19 (11) ◽  
pp. 595
Author(s):  
Yanan Xu ◽  
Patricia J. Harvey
Keyword(s):  
Dunaliella Salina ◽  
Uv Light ◽  
Red Light ◽  
General Effect ◽  
Health Food ◽  
Food Sector ◽  
Cosmetic Industry ◽  
Green Microalga ◽  
Massive Accumulation ◽  
Different Levels

Phytoene is a colourless natural carotenoid that absorbs UV light and provides antioxidant and anti-inflammatory activities as well as protection against photodamage. It is therefore valued for its skin health and aesthetic benefits by the cosmetic industry, as well as by the health food sector. The halotolerant green microalga Dunaliella salina is one of the richest sources of natural carotenoids. We have previously investigated the over-production of phytoene in D. salina after cultivation with the well-characterised mitosis inhibitor, chlorpropham. In this study, 15 herbicides with different modes of action were tested for their potential to promote phytoene accumulation. All herbicides showed different levels of capabilities to support phytoene over-production in D. salina. Most significantly, the two mitosis inhibitors tested in this study, propyzamide and chlorpropham, showed similar capacities to support the over-production of phytoene by D. salina cultures as phytoene desaturase inhibitors. The cellular content of phytoene increased by over 10-fold within 48 h of treatment with the mitosis inhibitors compared to untreated cultures. Results indicate a general effect of mitosis inhibitors on phytoene accumulation in D. salina. Furthermore, red light was found to significantly enhance the phytoene yield when used in combination with effective inhibitor treatments. Red light can be applied to maximize the production of phytoene from D. salina.

Pervasive Computing

2011 ◽  
pp. 44-68
Author(s):  
Emerson Loureiro ◽  
Glauber Ferreira ◽  
Hyggo Almeida ◽  
Angelo Perkusich
Keyword(s):  
Pervasive Computing ◽  
Research Areas ◽  
Theoretical Support ◽  
Academic Activities ◽  
Different Levels

In this chapter, we introduce the key ideas related to the paradigm of pervasive computing. We discuss its concepts, challenges, and current solutions by dividing it into four research areas. Such division is how we were able to understand what really is involved in pervasive computing at different levels. Our intent is to provide readers with introductory theoretical support in the selected research areas to aid them in their studies of pervasive computing. Within this context, we hope the chapter can be helpful for researchers of pervasive computing, mainly for the beginners, and for students and professors in their academic activities.

scholarly journals Ways of Efficiency Improvement of the Organization of Students’ Independent Work with Computer Technologies Usage

2018 ◽  
Vol 155 ◽  
pp. 01052 ◽  
Author(s):  
Inna Plotnikova ◽  
Oksana Efremova ◽  
Nataliya Chicherina ◽  
Victor Dalinger
Keyword(s):  
Independent Solution ◽  
Efficiency Improvement ◽  
The World ◽  
Four Levels ◽  
Effective Organization ◽  
The University ◽  
Independent Work ◽  
Experimental Group ◽  
Different Levels ◽  
Engineering Personnel

Recently the need for the qualified engineering personnel increases in the world. High-quality preparation of such shots begins at the university already with the first courses and it is directly connected with the effective organization of students’ independent work. In the article the organization of independent work when training students of technical colleges in mathematics with use of computer means is considered. The complex of the tasks developed by teachers included tasks in mathematics of four levels. It is shown that the independent solution of problems of different levels by the students of experimental group contributed to the development of mathematical abilities.

scholarly journals NEW MOLECULAR MECHANISM OF CEFTAZIDIME-INDUCED HUMAN RED BLOOD CELL HEMOLYSIS THROUGH THE PHOTOHEMOLYSIS REACTION

2018 ◽  
Vol 11 (15) ◽  
pp. 47
Author(s):  
Mashuri Mashuri ◽  
Achmad Zaini ◽  
Diana Rahmanisa ◽  
Muhammad Rifqi Alfiannoor ◽  
Muhammad Rosyhan Sanjaya ◽  
...  
Keyword(s):  
Blood Cell ◽  
Red Blood Cell ◽  
Uv Light ◽  
Light Exposure ◽  
Positive Control ◽  
Negative Control ◽  
Group 3 ◽  
Group 2 ◽  
Experimental Group ◽  
Group 1

Objective: The present study was undertaken to investigate the photohemolysis reaction through photosensitization reaction by ceftazidime as a photosensitizer in human red blood cell (RBC).Methods: In this present study, human erythrocytes have used a sample. The sample then divided into six groups consisting of Group 1 (T1) served a negative control which consists of erythrocytes and buffers phosphate with pH 6.8; Group 2 (T2) served as a positive control which consists erythrocytes and buffers phosphate with pH 6.8 and exposed to UV-light; and Group 3, 4, 5, and 6 (T3, T4, T5, and T6) served as an experimental group which consists of erythrocytes, buffer phosphate with pH 6.8, ceftazidime with concentration 10%, 20%, 30%, and 40%, respectively, and also exposed to UV-light. UV-light exposure was done in 2 h. After the treatment period, the level of hydrogen peroxide (H2O2), conjugated diene (CD), advanced oxidation protein products (AOPPs), and percentage of RBC hemolysis (RBCH) were measured.Results: The results of this present studies showed that ceftazidime significantly increases the levels of H2O2, CD, AOPPs, and percentage of RBCH during the UV radiation.Conclusion: The present study demonstrated that ceftazidime acts as a photosensitizer and induced the photohemolysis reaction in human RBC. Furthermore, the hemolysis of RBC seems through the protein damage than lipid damage.

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