1,310 research outputs found
The design of a Space-borne multispectral canopy LiDAR to estimate global carbon stock and gross primary productivity
Understanding the dynamics of the global carbon cycle is one of the most challenging issues for the scientific community. The ability to measure the magnitude of terrestrial carbon sinks as well as monitoring the short and long term changes is vital for environmental decision making. Forests form a significant part of the terrestrial biosystem and understanding the global carbon cycle, Above Ground Biomass (AGB) and Gross Primary Productivity (GPP) are critical parameters. Current estimates of AGB and GPP are not adequate to support models of the global carbon cycle and more accurate estimates would improve predictions of the future and estimates of the likely behaviour of these sinks. Various vegetation indices have been proposed for the characterisation of forests including canopy height, canopy area, Normalised Difference Vegetation Index (NDVI) and Photochemical Reflectance Index (PRI). Both NDVI and PRI are obtained from a measure of reflectivity at specific wavelengths and have been estimated from passive measurements. The use of multi-spectral LiDAR to measure NDVI and PRI and their vertical distribution within the forest represents a significant improvement over current techniques. This paper describes an approach to the design of an advanced Multi-Spectral Canopy LiDAR, using four wavelengths for measuring the vertical profile of the canopy simultaneously. It is proposed that the instrument be placed on a satellite orbiting the Earth on a sun synchronous polar orbit to provide samples on a rectangular grid at an approximate separation of 1km with a suitable revisit frequency. The systems engineering concept design will be presented
Dynamics of the peel front and the nature of acoustic emission during peeling of an adhesive tape
We investigate the peel front dynamics and acoustic emission of an adhesive
tape within the context of a recent model by including an additional
dissipative energy that mimics bursts of acoustic signals. We find that the
nature of the peeling front can vary from smooth to stuck-peeled configuration
depending on the values of dissipation coefficient, inertia of the roller, mass
of the tape. Interestingly, we find that the distribution of AE bursts shows a
power law statistics with two scaling regimes with increasing pull velocity as
observed in experiments. In this regimes, the stuck-peeled configuration is
similar to the `edge of peeling' reminiscent of a system driven to a critical
state.Comment: Accepted for publication in Phys. Rev. Let
UMBILICAL CORD BLOOD HEMATOLOGY IN RELATION WITH MATERNAL ANEMIA: A PRELIMINARY STUDY
Objectives: The aim of this study was to observe any umbilical cord blood hematological changes in relation to maternal anemia.Methods: We conducted a cross-sectional study on 220 neonates and their mothers from August 1, 2015, to July 31, 2016, in collaboration with the Department of Obstetrics and Gynaecology, Regional Institute of Medical Sciences, Imphal, India. Immediately after vaginal delivery of baby, umbilical cord was clamped and blood was collected in EDTA vials and analyzed using automated hematoanalyzer.Results: Neonates of non-anemic mothers had significantly higher level of hemoglobin concentration than neonates of anemic mothers. Total leukocyte count (TLC) was slightly higher in neonates of non-anemic mothers as compared to neonates of anemic mothers. Platelet count was slightly higher in neonates of anemic mothers as compared to non-anemic mothers, but platelet crit, mean platelet volume, and platelet cell distribution width were slightly higher in neonates of non-anemic mothers than neonates anemic mothers.Conclusions: It was a preliminary study. A similar type of the study must be conducted in future to comprehend the effect of various other factors affecting delivery such as maternal anemia, diet, and environment on blood parameters of newborns
Network Structure, Topology and Dynamics in Generalized Models of Synchronization
We explore the interplay of network structure, topology, and dynamic
interactions between nodes using the paradigm of distributed synchronization in
a network of coupled oscillators. As the network evolves to a global steady
state, interconnected oscillators synchronize in stages, revealing network's
underlying community structure. Traditional models of synchronization assume
that interactions between nodes are mediated by a conservative process, such as
diffusion. However, social and biological processes are often non-conservative.
We propose a new model of synchronization in a network of oscillators coupled
via non-conservative processes. We study dynamics of synchronization of a
synthetic and real-world networks and show that different synchronization
models reveal different structures within the same network
Review: Genetic manipulation of the rodent placenta
The principal role of the placenta is the maintenance of pregnancy and promotion of fetal growth and viability. The use of transgenic rodents has greatly enhanced our understanding of placental development and function. However, embryonic lethality is often a confounding variable in determining whether a genetic modification adversely affected placental development. In these cases, it is beneficial to specifically manipulate the placental genome. The purpose of this review is to summarize available methodologies for specific genetic modification of the rodent placenta. By restricting genetic alterations to the trophoblast lineage, it is possible to gain a deeper understanding of placental development that perhaps will lead to gene-targeted therapies to rescue irregular placentation in transgenic animals or in women at high-risk for placenta-associated pregnancy complications
Recommended from our members
Intentionally Iranian: Belonging, the Iranian Monolith, and Solidarities within the Iranian Diaspora in Colorado
The Iranian diaspora is a diverse, intricate, and burgeoning demographic consisting of individuals from a plethora of religious, ethnic, racial, and gender identities. Analyses of the Iranian diaspora thus far tend to focus on visibly large populations of Iranians primarily found in European countries like Germany, and larger cities in the United States such as Los Angeles, Washington D.C (along with the Maryland and Virginia areas), and Texas. Studies of the Iranian diaspora in places with less prominent physical markers are not as readily researched. This thesis seeks to disrupt that status by examining the Iranian diaspora present in Colorado, primarily the Boulder and closely surrounding areas. Posited more specifically: how do space and place influence, support, and transform semblances of belonging, conceptions of an Iranian monolith, and solidarity measures within the Iranian diaspora in Colorado? Through eight in depth, semi-structured, qualitative interviews with members of the diaspora who have either lived or currently live in Boulder or nearby areas, the question of intentionally enacting aspects of one’s Iranian identity is explored within the context of spatial realities. By drawing on formative frameworks from scholars and knowledge keepers on race, intersectionality, and the Iranian diaspora, the liminal nature of Iranians in Colorado— within the diaspora as a whole, themselves, and the surrounding society—is asserted as relating significantly to understanding identity, belonging, and formation within this populace. As the premiere study on Iranians in Colorado, this exploration seeks to amplify the experiences and perspectives of this demographic and illuminate key relationships between spatiality and personhood integral in the furthering of multifaceted disciplines such as Iranian diasporic studies in intersectional, critical ways. </p
Mollusks (Gastropoda and Bivalvia) of the multiple-use reserve martín garcía Island, Río de la plata river: biodiversity and ecology
The Island of Martin Garcia is located in the Upper Río de la Plata, to the south of mouth the Uruguay River. The aim of the present study was to analyse the biodiversity of the island freshwater mollusks and their relationships to environmental variables. Twelve sampling sites were selected, five were along the littoral section of the island and seven were Inland ponds. Seven major environmental variables were measured: water and air temperature, percentage of oxygen saturation, dissolved oxygen, electrical conductivity, total dissolved solids and pH. Twenty-seven mollusk species were found, Antillorbis nordestensis, Biomphalaria tenagophila tenagophila, B. t. guaibensis, B. straminea, B. peregrina, Drepanotrema kermatoides, D. cimex, D. depressissimum, Chilina fluminea, C. rushii, C. megastoma, Uncancylus concentricus, Hebetancylus moricandi, Stenophysa marmorata, Heleobia piscium, H. parchappii, Potamolithus agapetus, P. buschii, P. lapidum, Pomacea canaliculata, P. megastoma Asolene platae, Corbicula fluminea, Eupera platensis, Pisidium sterkianum, P. taraguyense and Limnoperna fortunei. UPGMA clustering of species based on their occurrence in different ecological conditions revealed two main species groups. The Canonical Correspondence Analysis suggests that the species distribution is related to the physico-chemical condition of water. Axis two of the ordination diagram displayed the approximately 95.6% of the correlation between species and environmental variables. Dissolved oxygen, conductivity, water temperature and pH showed the highest fluctuations during the sampling period. The species richness (S) showed relationships mainly with water temperature and conductivity. The biodiversity of the gastropods and bivalves from Martín García Island amounts to up to 26 species. Among the Gastropoda, the Planorbidae family made the most sizeable contribution. The Lithogliphidae P. agapetus (26.28%) and P. buschii (9.50%) showed the highest relative frequencies of occurrence within the littoral environments, while the Planorbidae D. cimex (23.83%) and D. kermatoides (11.59%) likewise did so in the inland ponds
Obturations en amalgame et modifications des lymphocytes T
Dental amalgam and nickel alloys have been considered quite safe. Previous authors reported the effect of dental amalgam and nickel alloys on human T-lymphocytes modifications after amalgam dental fillings, into dose-dependence of any modifications and into possible temporary.Eight patients were subjected to dental care with amalgam dental fillings. Drawings of blood were executed at start, fifteen days after late fillings and two months later.The results about modifications of T-lymphocytes were not univocal. We believe, at now, that temporary modifications of the immunity seem to be related to a cytotoxic mechanism.Les auteurs ont étudié les modifications systémiques des lymphocytes T (T3) et des sous-populations T4 et T8 après la pose d’obturations en amalgame. Les résultats ne sont pas univoques et leur interprétation n’est pas facile.On pense que l’amalgame dentaire pourrait provoquer une modification transitoire et temporaire des défenses immunitaires par un mécanisme de cytotoxicité
- …