135 research outputs found
Observing soil organic carbon spatial and seasonal variability at the Golan Heights using Rock-Eval measurements
No full textSoil organic matter (SOM) stores most of the terrestrial carbon, and changes in this storage can have a significant effect on the global carbon cycle. Various approaches have been used to understand the SOM transformations and stability. Here, we estimated the long-term SOM stability, and the effect of decomposition on the stability and composition of the remaining fraction, by Rock-Eval pyrolysis. The sampling took place in Mount Baron, the Golan Heights, in October 2021, February 2022, and June 2022, which represent the beginning, middle, and end of the rainy season. . Each sample was pooled from 2 locations and taken by a trowel from A-horizon at 0-10 cm depth.. At each campaign, the soil was sampled at 4 heights along the north and south slopes, under tree canopy, and in open grassland. In addition, to study the different fractions of organic matter, we analyzed soil separated into particulate organic matter (POM) and mineral-associated organic matter (MAOM). The samples were dried to 55°C and were ground with a mortar and pestle before the Rock-Eval analysis (Rock Eval 6, Vinci Technologies, at Ben Gurion University of the Negev for October samples and Rock Eval 7S, Vinci Technologies, at the Geological Survey of Israel for February and June samples)
Observing soil organic carbon spatial and seasonal variability at the Golan Heights using CO2/O2 fluxes measurements in an incubation experiment
No full textSoil organic matter (SOM) stores most of the terrestrial carbon, and changes in this storage can have a significant effect on the global carbon cycle. Various approaches have been used to understand the SOM transformations and stability. Here we measured the respiratory CO2 and O2 fluxes, and their ratio (the Apparent Respiratory Quotient - ARQ) in soil incubations at different temperatures, to learn about the short-term processes affecting SOM stability. To study in detail the spatial and temporal variability, we examine soil samples from two sample sets: a regional set, and a local set that was used to study the seasonality and environmental variability within a site. The regional set was taken from 11 sites located in the north and center of the Golan Heights, the samplings took place in two campaigns in October 2020 and in January 2021. In each site, the sample was pooled from 2 sub-samples taken by a trowel from A-horizon at 0-10 cm depth in adjacent locations. The local soil samples set was taken from Mt. Baron, a volcanic cinder cone which is located in the north of Golan Heights. The sampling took place in October 2021, February 2022, and June 2022, which represent the beginning, middle, and end of the rainy season. Each sample was pooled from 2 locations and taken by a trowel from A-horizon at 0-10 cm depth. At each campaign, the soil was sampled at 4 heights along the north and south slopes, under tree canopy, and in open grassland. The incubations were conducted on fresh sieved soil (2mm), wetted with distilled water to different levels. To explore the effect of anaerobic microsites on ARQ we incubated artificial clods (1 cm diameter) with wetted soil from Mt. Baron (The local set). To further test the effects of O2 limitation we conducted an experiment in which we mitigated this limitation by enriching in oxygen the atmosphere of the incubation headspace. All the incubations were carried out at the Hebrew University of Jerusalem
Pool [I. Weisman]
No full textTitre : Pool Tous droits réservés Réalisateur : Ido Weisman Scénariste : Ido Weisman Année : 2018 Durée : 12' Pays : Israël Langue : hébreu Genre : fiction Couleur/Noir et blanc : Couleur Distribution/casting : Ilan Hazan, Yoav Keren, Adam Glants, Guy Golan, Roy Gueta, Noam Jablonowsky Synopsis : Une chaude matinée de printemps dans la piscine publique du kibboutz. Aryeh (60 ans) ne sait pas nager, il est donc conduit dans le grand bain par le moniteur de natation qui, selon lui, est cel..
Bifurcations of equilibria in DNA elasticity
No full textDNA molecules in the familiar double helical B form are treated here as though they have rod-like structures obtained by stacking the
nearly planar base pairs comprising them one on top of another with each rotated by approximately one-tenth of a full turn with respect
to its immediate predecessor in the stack. As each base in a base pair is attached to the sugar-phosphate backbone chain of one of the
two DNA strands that have come together to form the Watson-Crick structure, and each phosphate group in a backbone chain bears one electronic charge, two such charges are associated with each base pair. Thus, each base pair is subject to not only the elastic forces and moments exerted on it by its neighboring base pairs but also to remote electrostatic forces that, because they are only partially screened out by positively charged counter ions, can render the molecule's equilibrium configurations sensitive to changes in the concentration c of salt in the medium.
The observation that the step from one base pair to the next can be one of several distinct types, each having its own mechanical properties that depend on the nucleotide composition of the step, and the assumption that a base pair is rigid, led to the development of a theory of sequence dependent DNA elasticity [Coleman, Olson, and Swigon, J. Chem. Phys. 118 ,7127-7140, (2003)]. The theory of DNA molecules in aqueous solution developed here is based on but goes beyond that theory. It takes into account the intramolecular electrostatic interactions of the negatively charged phosphate groups in the molecule and the impenetrability of the DNA molecule for cases in which the
electrostatic repulsive forces do not suffice to avoid self penetration. The theory permits one to calculate equilibrium configurations, to determine their stability, and to study the dependence of them on salt concentration and on all kinds of end conditions.
When the intramolecular electrostatic forces are taken into account, the equations of mechanical equilibrium for a DNA molecule with N+1 base pairs are a system of mu*N non-linear equations, where mu, the number of kinematical variables describing the relative displacement and orientation of adjacent base pairs is in general 6; it reduces to 3 when base-pair steps are assumed to be inextensible and non-shearable. An efficient numerically stable computational scheme is here presented for
solving those equations and determining the mechanical stability of the calculated equilibrium configurations. That scheme is employed to compute and analyze bifurcation diagrams in which c is the bifurcation parameter and to show that, for an intrinsically curved molecule, small changes in c can have a strong effect on stable
equilibrium configurations. Cases are presented in which self-contact must be taken into account even though the intramolecular electrostatic forces of repulsion are strong.Ph.D.Includes bibliographical references (p. 106-110)
Gonadotropins in the Russian Sturgeon: Their Role in Steroid Secretion and the Effect of Hormonal Treatment on Their Secretion.
No full textIn the reproduction process of male and female fish, pituitary derived gonadotropins (GTHs) play a key role. To be able to specifically investigate certain functions of Luteinizing (LH) and Follicle stimulating hormone (FSH) in Russian sturgeon (Acipenser gueldenstaedtii; st), we produced recombinant variants of the hormones using the yeast Pichia pastoris as a protein production system. We accomplished to create in vitro biologically active heterodimeric glycoproteins consisting of two associated α- and β-subunits in sufficient quantities. Three dimensional modelling of both GTHs was conducted in order to study the differences between the two GTHs. Antibodies were produced against the unique β-subunit of each of the GTHs, in order to be used for immunohistochemical analysis and to develop an ELISA for blood and pituitary hormone quantification. This detection technique revealed the specific localization of the LH and FSH cells in the sturgeon pituitary and pointed out that both cell types are present in substantially higher numbers in mature males and females, compared to immature fish. With the newly attained option to prevent cross-contamination when investigating on the effects of GTH administration, we compared the steroidogeneic response (estradiol and 11-Keto testosterone (11-KT) in female and males, respectively) of recombinant stLH, stFSH, and carp pituitary extract in male and female sturgeon gonads at different developmental stages. Finally, we injected commercially available gonadotropin releasing hormones analog (GnRH) to mature females, and found a moderate effect on the development of ovarian follicles. Application of only testosterone (T) resulted in a significant increase in circulating levels of 11-KT whereas the combination of GnRH + T did not affect steroid levels at all. The response pattern for estradiol demonstrated a similar situation. FSH levels showed significant increases when GnRH + T was administered, while no changes were present in LH levels
Indirect Assessment of Beliefs About the Self: Implicit Self-Criticism - Materials, Data, and Analysis Scripts
No full textMaterials, data and analysis scripts accompanying Indirect Assessment of Beliefs About the Self: Implicit Self-Criticism, A doctoral dissertation submitted to Ben-Gurion University of the Negev by Michael Pinus, November 2020. The repository contains materials, analysis scripts, and data of five validation studies of indirect measures of self-criticism
Appraising Contemporary Strategies to Combat Multidrug Resistant Gram-Negative Bacterial Infections–Proceedings and Data From the Gram-Negative Resistance Summit
No full textThe emerging problem of antibiotic resistance, especially among Gram-negative bacteria (GNB), has become a serious threat to global public health. Very few new antibacterial classes with activity against antibiotic-resistant GNB have been brought to market. Renewed and growing attention to the development of novel compounds targeting antibiotic-resistant GNB, as well as a better understanding of strategies aimed at preventing the spread of resistant bacterial strains and preserving the efficacy of existing antibiotic agents, has occurred. The Gram-Negative Resistance Summit convened national opinion leaders for the purpose of analyzing current literature, epidemiologic trends, clinical trial data, therapeutic options, and treatment guidelines related to the management of antibiotic-resistant GNB infections. After an in-depth analysis, the Summit investigators were surveyed with regard to 4 clinical practice statements. The results then were compared with the same survey completed by 138 infectious disease and critical care physicians and are the basis of this article. © 2011 Author(s)
A policy model for Tunisia with real and financial flows
No full textThis model was developed to provide a moacroeconomic framework for Tunisia's structural adjustment program and a flexible tool for further country economic analysis. As currently specified, it is designed to analyze fiscal, debt, and incomes policies, while deriving implications for the exchange rate and for the availability of credit to the private sector. Several policy experiments are carried out to illustrate this focus, and suggestions are offered for variations in model closure and detail.Economic Theory&Research,Environmental Economics&Policies,Banks&Banking Reform,Economic Stabilization,Financial Intermediation
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