scholarly journals Patterns of Reproductive and Seed Dispersal and Ecological Significance of the Clonal Spring Ephemeroid Plant Carex physodes in the Gurbantuggut Desert

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
B. ABUDUREHEMAN ◽  
Y. CHEN ◽  
X. LI ◽  
L. ZHANG ◽  
H. LIU ◽  
...  

ABSTRACT: Carex physodes is an ephemeral species in the cold desert of Gurbantunggut in Northwest China. It has both asexual and sexual reproductive patterns. The primary aims of this study were to characterize the reproduction systems and identify the role of fruit dispersal in the sexual reproduction of C. physodes. Aboveground and underground biomass, root-shoot ratio, inflorescence biomass, fruit-set of C. physodes were measured and dispersal of perigynia and achenes in the natural habitat and indoor condition were studied. The underground biomass of C. physodes was approximately 10 times more than the aboveground biomass. The most parts of aboveground biomass is allocated to the inflorescence, which suggests that C. physodes allocates most biomass to the reproductive part. C. physodes produces perigynium with a pericarp containing one achene. The perigynia disperse at a much greater distance than achenes at both 1 and 4 m s-1 wind velocity, and the floating time of perigynia in water was much longer than that of achenes. Perigynia can hold more water and adher soil much more easily than achenes, which suggests that perigynia are suitable for wind dispersal, and they also adapt to spread at a long distance by occasionally rainfall. However, achenes may remain near the mother plants and only disperse at short distances. C. physodes is morphologically and physiologically adapted to the cold desert environment via a combination of characters associated with the rhizomatous and perigynium. This adaption may increase the opportunity of survival and expansion of population of C. physodes.

2014 ◽  
Vol 4 (2) ◽  
pp. 106-112
Author(s):  
Anita Shrivastava ◽  
Andrea Burianova

This study aimed to explore the relationships between attachment styles, proximity, and relational satisfaction. This was achieved by assessing a distinct type of long distance romantic relationship of flying crews, compared with proximal (non-flying crew) romantic relationships. The responses of 139 expatriate professionals revealed significant associations between proximity and anxious and avoidant attachment dimensions. The role of the avoidant dimension in comparison with that of the anxious dimension was found to be a significant predictor of relational satisfaction. This study contributes significantly toward addressing the role of proximity and attachment in relational satisfaction in a new context of geographic separation.


This interdisciplinary volume presents nineteen chapters by Roman historians and archaeologists, discussing trade in the Roman Empire in the period c.100 BC to AD 350, and in particular the role of the Roman state, in shaping the institutional framework for trade within and outside the Empire, in taxing that trade, and in intervening in the markets to ensure the supply of particular commodities, especially for the city of Rome and for the army. The chapters in this volume address facets of the subject on the basis of widely different sources of evidence—historical, papyrological, and archaeological—and are grouped in three sections: institutional factors (taxation, legal structures, market regulation, financial institutions); evidence for long-distance trade within the Empire, in wood, stone, glass, and pottery; and trade beyond the frontiers, with the East (as far as China), India, Arabia, and the Red Sea, and the Sahara. Rome’s external trade with realms to the east emerges as being of particular significance to the fisc. But in the eastern part of the Empire at least, the state appears, in collaboration with the elite holders of wealth, to have adapted the mechanisms of taxation, both direct and indirect, to support its need for revenue. On the other hand, the price of that collaboration, which was in effect a fiscal partnership, in slightly different forms in East and West, in the longer term fundamentally changed the political character of the Empire.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Aditya Ghoshal ◽  
Anuradha Bhat

AbstractShoaling decisions in the wild are determined by a combination of innate preferences of the individual along with the interplay of multiple ecological factors. In their natural habitat as well as in the laboratory, zebrafish is a shoaling fish. Here, we investigate the role of group size and associated vegetation in shaping shoaling preferences of wild male zebrafish. We studied the association preference of males to groups of female shoals in a multi-choice test design. We found that males made greater proportion of visits to an 8-female group compared to 2 and 4-female groups. However, males spent similar proportions of time across the three female-containing groups. When artificial vegetation was incorporated along with female number as an additional factor, we found that males prefer high and moderately vegetated patches compared to low or no-vegetation groups, irrespective of the number of females in these patches. Based on experiments using a novel multi-choice design, our results show that preference for group size can change due to interaction of two separate factors. This work is a first attempt to understand the role of aquatic flora in determining shoaling preferences in zebrafish, using an experimental paradigm consisting of a gradation in female and vegetation densities.


2019 ◽  
Vol 24 ◽  
pp. 121-128
Author(s):  
Sigal Ben-Zaken ◽  
Yoav Meckel ◽  
Dan Nemet ◽  
Alon Eliakim

The ACSL A/G polymorphism is associated with endurance trainability. Previous studies have demonstrated that homozygotes of the minor AA allele had a reduced maximal oxygen consumption response to training compared to the common GG allele homozygotes, and that the ACSL A/G single nucleotide polymorphism explained 6.1% of the variance in the VO2max response to endurance training. The contribution of ACSL single nucleotide polymorphism to endurance trainability was shown in nonathletes, however, its potential role in professional athletes is not clear. Moreover, the genetic basis to anaerobic trainability is even less studied. Therefore, the aim of the present study was to examine the prevalence of ACSL single nucleotide polymorphism among professional Israeli long distance runners (n=59), middle distance runners (n=31), sprinters and jumpers (n=48) and non-athletic controls (n=60). The main finding of the present study was that the ACSL1 AA genotype, previously shown to be associated with reduced endurance trainability, was not higher among sprinters and jumpers (15%) compared to middle- (16%) and long-distance runners (15%). This suggests that in contrast to previous studies indicating that the ACSL1 single nucleotide polymorphism may influence endurance trainability among non-athletic individuals, the role of this polymorphism among professional athletes is still not clear.


2016 ◽  
Vol 43 (2) ◽  
pp. 105 ◽  
Author(s):  
Lu Wang ◽  
Yong-Ling Ruan

Roots and shoots are distantly located but functionally interdependent. The growth and development of these two organ systems compete for energy and nutrient resource, and yet, they keep a dynamic balance with each other for growth and development. The success of such a relationship depends on efficient root-shoot communication. Aside from the well-known signalling processes mediated by hormones such as auxin and cytokinin, sugars have recently been shown to act as a rapid signal to co-ordinate root and shoot development in response to endogenous and exogenous clues, in parallel to their function as carbon and energy resources for biomass production. New findings from studies on vascular fluids have provided molecular insights into the role of sugars in long-distance communications between shoot and root. In this review, we discussed phloem- and xylem- translocation of sugars and the impacts of sugar allocation and signalling on balancing root–shoot development. Also, we have taken the shoot–root carbon–nitrogen allocation as an example to illustrate the communication between the two organs through multi-layer root–shoot–root signalling circuits, comprising sugar, nitrogen, cytokinin, auxin and vascular small peptide signals.


Parasitology ◽  
2009 ◽  
Vol 136 (4) ◽  
pp. 443-452 ◽  
Author(s):  
M. PFÄFFLE ◽  
T. PETNEY ◽  
M. ELGAS ◽  
J. SKUBALLA ◽  
H. TARASCHEWSKI

SUMMARYAlthough there is an increasing understanding of the role of parasites in their host dynamics, accurate, quantitative estimates of parasite caused morbidity in wild animals are rare. Here, we examine the possible impact of 2 tick species (Ixodes ricinus, I. hexagonus) on the condition of the European hedgehog (Erinaceus europaeus). For this, we tested for correlations between blood parameters of 36 adult hedgehogs from an experimental population enclosed in a natural habitat and their tick infestation over a period of 8 months (March–October 2007). We found correlations between the tick infestation and the concentration of red blood cells, haemoglobin, haematocrit, MCH, MCHC, thrombocytes, lymphocytes and neutrophils. These results indicate that ticks can induce anaemia in the hedgehog. The peripheral blood characteristics and the erythrocyte indices characterize this anaemia as haemorrhagic and regenerative. During the course of our study the hedgehogs of our population showed below normal mortality but morbidity was found to be high resulting from the blood loss caused by the feeding activity of the ticks.


Development ◽  
1999 ◽  
Vol 126 (16) ◽  
pp. 3585-3596 ◽  
Author(s):  
D. Engelkamp ◽  
P. Rashbass ◽  
A. Seawright ◽  
V. van Heyningen

Post-mitotic neurons generated at the rhombic lip undertake long distance migration to widely dispersed destinations, giving rise to cerebellar granule cells and the precerebellar nuclei. Here we show that Pax6, a key regulator in CNS and eye development, is strongly expressed in rhombic lip and in cells migrating away from it. Development of some structures derived from these cells is severely affected in Pax6-null Small eye (Pax6(Sey)/Pax6(Sey)) embryos. Cell proliferation and initial differentiation seem unaffected, but cell migration and neurite extension are disrupted in mutant embryos. Three of the five precerebellar nuclei fail to form correctly. In the cerebellum the pre-migratory granule cell sub-layer and fissures are absent. Some granule cells are found in ectopic positions in the inferior colliculus which may result from the complete absence of Unc5h3 expression in Pax6(Sey)/Pax6(Sey) granule cells. Our results suggest that Pax6 plays a strong role during hindbrain migration processes and at least part of its activity is mediated through regulation of the netrin receptor Unc5h3.


2021 ◽  
Vol 2 (4) ◽  
pp. 27-50
Author(s):  
Saroj Pokharel ◽  
Dipak Tharu ◽  
Yagya Murti Pandey

The study aims to investigate the role of livelihood diversification and social capital for the households’ movement, and also to explore the identity and bond of social capital and livelihood diversification to achieve an improved lifestyle. Human relations significantly create a network society, impalpable resource of community, shared values and trust which we draw upon in our daily lives. Livelihood diversification is a community-practised strategy for managing economic and income diversity in poverty reduction. It has highly emphasized income and well-being to diversify livelihood. It also turns the likely norms and networks with the households from exploiting new economic opportunities even in the future. This study responds to why people are migrating from the surrounding and the long distance of Kathmandu, and largely dependent on direct cash incomes from informal activities. It used qualitative approaches such as ethnography, case studies, participant observation, etc. to study the relationship between households and social capital level and livelihood diversification. Hence, the effects of social capital and livelihood diversification were found protecting households’ income. The major findings also show the social supportive network index which has significant effects on the households’ ability to learn a new livelihood. Income generations similarly affect the household capacity to secure a home and the socio-economic condition of households. This study can be advantageous for making both local and urban policy to diversify household livelihoods and social capital as well as applicable for new researchers in social sciences. Most importantly, it helps readers perceive new ways of promoting livelihood diversification and social capital and as a whole social advancement in Central Nepal.


2021 ◽  
Vol 59 (1) ◽  
pp. 287-289

Andreas Grein of Zicklin School of Business, Baruch College, City University of New York reviews “Outside the Box: How Globalization Changed from Moving Stuff to Spreading Ideas,” by Marc Levinson. The Econlit abstract of this book begins: “Explores the development of globalization in the early twenty-first century, focusing on the role of transportation, communication, and information technology in enabling firms to organize their businesses around long-distance value chains.”


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