60 research outputs found
The Riddle of Gravitation
There is no doubt that both the special and general theories of relativity
capture the imagination. The anti-intuitive properties of the special theory of
relativity and its deep philosophical implications, the bizzare and dazzling
predictions of the general theory of relativity: the curvature of spacetime,
the exotic characteristics of black holes, the bewildering prospects of
gravitational waves, the discovery of astronomical objects as quasers and
pulsers, the expansion and the (possible) recontraction of the universe..., are
all breathtaking phenomena. In this paper, we give a philosophical
non-technical treatment of both the special and the general theory of
relativity together with an exposition of some of the latest physical theories.
We then give an outline of an axiomatic approach to relativity theories due to
Andreka and Nemeti that throws light on the logical structure of both theories.
This is followed by an exposition of some of the bewildering results
established by Andreka and Nemeti concerning the foundations of mathematics
using the notion of relativistic computers. We next give a survey on the
meaning and philosophical implications of the the quantum theory and end the
paper by an imaginary debate between Einstein and Neils Bohr reflecting both
Einstein's and Bohr's philosophical views on the quantum world.
The paper is written in a somewhat untraditional manner; there are too many
footnotes. In order not to burden the reader with all the details, we have
collected the more advanced material the footnotes. We think that this makes
the paper easier to read and simpler to follow. The paper in full is adressed
more to experts.Comment: 40 pages, LaTeX-fil
Possible alternative for national supply of seed potatoes (Solanum tuberosum L.) from in vitro culture at the Agro-physio-genetic and Plants Biotechnology laboratory of IPR / IFRA of Katibougou, Mali
The enhancement of the potential for reducing food insecurity and poverty through potato cultivation in Mali is largely limited by difficult access to quality seed. In trying to find ways to reduce these shortcomings outlined above that work has been done. The objective of this work was to assess the economic profitability of the local potato seed sourcing scheme from in vitro propagation and to analyze the competitiveness of the sourcing scheme from imported elite seed. The technical and economic feasibility of the local potato seed supply scheme was assessed at five levels. The first concerns the production of vitro-plants in the laboratory, the second the production of mini zero generation tubers (G0). Regarding the other three levels of evaluation, they were carried out in collaboration with the seed cooperatives by successive multiplication from mini-tubers to obtain seeds of one âG1â, two âG2â and three âG3â generations". The profitability of the procurement scheme from the elite imported and multiplied once seed was evaluated in order to analyze its competitiveness in relation to the local circuit. The valuation indicates positive profit margins. However, it should be noted that the economic efficiency coefficients of vitro-propagation (0.77) and tunnel multiplication (0.75) are less than 1. The production cost of one kilogram of G3 is equal to at 463.39 F CFA. A profit margin of 456.61 F CFA / kg emerges between this unit production cost and the selling price of imported seeds, which amounts on average to 920 F CFA / kg. The production of plants is technically feasible and profitable with a cost price of one kg of G3 in the order of 500 to 600 F CFA against 900 to 1000 F CFA / kg for imported seed.
La valorisation du potentiel de rĂ©duction de lâinsĂ©curitĂ© alimentaire et de la pauvretĂ© Ă travers la culture de la pomme de terre au Mali est limitĂ©e en grande partie par lâaccĂšs difficile Ă la semence de qualitĂ©. En essayant de trouver des moyens pour rĂ©duire ces insuffisances soulignĂ©es ci-dessus que ce travail a Ă©tĂ© effectuĂ©. Le prĂ©sent travail avait pour objectif dâĂ©valuer la rentabilitĂ© Ă©conomique du schĂ©ma dâapprovisionnement locale en semences de pomme de terre Ă partir de la vitro propagation et dâanalyser la compĂ©titivitĂ© du schĂ©ma dâapprovisionnement Ă partir de la semence Ă©lite importĂ©es. La faisabilitĂ© technico-Ă©conomique du schĂ©ma dâapprovisionnement local en semences de pomme de terre Ă©tait Ă©valuĂ©e Ă cinq niveaux. Le premier concerne la production de vitro-plants au laboratoire, le deuxiĂšme la production de mini tubercules de gĂ©nĂ©ration zĂ©ro (G0). Pour ce qui concerne les trois autres niveaux dâĂ©valuation, ils ont Ă©tĂ© rĂ©alisĂ©s en collaboration avec les coopĂ©ratives semenciĂšres par multiplications successives Ă partir de mini-tubercules pour obtenir des semences de gĂ©nĂ©ration une «G1», deux «G2» et trois «G3». La rentabilitĂ©, du schĂ©ma dâapprovisionnement Ă partir de la semence Ă©lite importĂ©e et multipliĂ©e une fois, a Ă©tĂ© Ă©valuĂ©e en vue dâanalyser sa compĂ©titivitĂ© en rapport avec le circuit local. LâĂ©valuation indique des marges bĂ©nĂ©ficiaires positives. Cependant, il faut remarquer que les coefficients dâefficacitĂ© Ă©conomiques de la vitro-propagation (0,77) et de la multiplication sous tunnels (0,75) sont infĂ©rieurs Ă 1. Le coĂ»t de production dâun kilogramme de G3 est Ă©gal Ă 463,39 F CFA. Une marge bĂ©nĂ©ficiaire de 456,61 F CFA / kg se dĂ©gage entre ce coĂ»t de production unitaire et le prix de vente des semences importĂ©es qui sâĂ©lĂšve en moyenne Ă 920 F CFA / kg. La production de plants est techniquement faisable et rentable avec un coĂ»t de revient dâun kg de G3 de lâordre de 500 Ă 600 F CFA contre 900 Ă 1 000 F CFA / kg pour la semence importĂ©e
SUCCESSFUL TWO PREGNANCIES IN ACHONDROPLASIC MOTHER, A CASE REPORT
The word achondroplasia is derived from Greek and means "without cartilage formation," although individuals with achondroplasia do have cartilage.
In genetics, dominance describes the effects of the different versions of a particular gene on the phenotype of an organism. Many animals (including humans) and plants have two copies of each gene in their genome, one inherited from each parent
Telleparallel Lagrange Geometry and a Unified Field Theory: Linearization of the Field Equations
The present paper is a natural continuation of our previous paper:
"Teleparallel Lagrange geometry and a unified field theory, Class. Quantum
Grav., 27 (2010), 045005 (29pp)" \cite{WNA}. In this paper, we apply a
linearization scheme on the field equations obtained in \cite{WNA}. Three
important results under the linearization assumption are accomplished. First,
the vertical fundamental geometric objects of the EAP-space loose their
dependence on the positional argument . Secondly, our linearized theory in
the Cartan-type case coincides with the GFT in the first order of
approximation. Finally, an approximate solution of the vertical field equations
is obtained.Comment: 18 pages, LaTeX fil
Extended Absolute Parallelism Geometry
In this paper, we study Absolute Parallelism (AP-) geometry on the tangent
bundle of a manifold . Accordingly, all geometric objects defined in
this geometry are not only functions of the positional argument , but also
depend on the directional argument . Moreover, many new geometric objects,
which have no counterpart in the classical AP-geometry, emerge in this
different framework. We refer to such a geometry as an Extended Absolute
Parallelism (EAP-) geometry. The building blocks of the EAP-geometry are a
nonlinear connection assumed given a priori and linearly independent
vector fields (of special form) defined globally on defining the
parallelization. Four different -connections are used to explore the
properties of this geometry. Simple and compact formulae for the curvature
tensors and the W-tensors of the four defined -connections are obtained,
expressed in terms of the torsion and the contortion tensors of the EAP-space.
Further conditions are imposed on the canonical -connection assuming that it
is of Cartan type (resp. Berwald type). Important consequences of these
assumptions are investigated. Finally, a special form of the canonical
-connection is studied under which the classical AP-geometry is recovered
naturally from the EAP-geometry. Physical aspects of some of the geometric
objects investigated are pointed out and possible physical implications of the
EAP-space are discussed, including an outline of a generalized field theory on
the tangent bundle of Comment: 27 pages, LaTeX-file, The last version of this paper was replaced by
mistake (by arXiv: 0905.0209[gr-qc]
Teleparallel Lagrange Geometry and a Unified Field Theory
In this paper, we construct a field theory unifying gravity and
electromagnetism in the context of Extended Absolute Parallelism (EAP-)
geometry. This geometry combines, within its structure, the geometric richness
of the tangent bundle and the mathematical simplicity of Absolute Parallelism
(AP-) geometry. The constructed field theory is a generalization of the
Generalized Field Theory (GFT) formulated by Mikhail and Wanas. The theory
obtained is purely geometric. The horizontal (resp. vertical) field equations
are derived by applying the Euler-Lagrange equations to an appropriate
horizontal (resp. vertical) scalar Lagrangian. The symmetric part of the
resulting horizontal (resp. vertical) field equations gives rise to a
generalized form of Einstein's field equations in which the horizontal (resp.
vertical) energy-momentum tensor is purely geometric. The skew-symmetric part
of the resulting horizontal (resp. vertical) field equations gives rise to a
generalized form of Maxwell equations in which the electromagnetic field is
purely geometric. Some interesting special cases, which reveal the role of the
nonlinear connection in the obtained field equations, are examined. Finally,
the condition under which our constructed field equations reduce to the GFT is
explicitly established.Comment: Latex file, 33 page
Variation in capsidiol sensitivity between Phytophthora infestans and Phytophthora capsici is consistent with their host range.
Plants protect themselves against a variety of invading pathogenic organisms via sophisticated defence mechanisms. These responses include deployment of specialized antimicrobial compounds, such as phytoalexins, that rapidly accumulate at pathogen infection sites. However, the extent to which these compounds contribute to species-level resistance and their spectrum of action remain poorly understood. Capsidiol, a defense related phytoalexin, is produced by several solanaceous plants including pepper and tobacco during microbial attack. Interestingly, capsidiol differentially affects growth and germination of the oomycete pathogens Phytophthora infestans and Phytophthora capsici, although the underlying molecular mechanisms remain unknown. In this study we revisited the differential effect of capsidiol on P. infestans and P. capsici, using highly pure capsidiol preparations obtained from yeast engineered to express the capsidiol biosynthetic pathway. Taking advantage of transgenic Phytophthora strains expressing fluorescent markers, we developed a fluorescence-based method to determine the differential effect of capsidiol on Phytophtora growth. Using these assays, we confirm major differences in capsidiol sensitivity between P. infestans and P. capsici and demonstrate that capsidiol alters the growth behaviour of both Phytophthora species. Finally, we report intraspecific variation within P. infestans isolates towards capsidiol tolerance pointing to an arms race between the plant and the pathogens in deployment of defence related phytoalexins
BLOOM: A 176B-Parameter Open-Access Multilingual Language Model
Large language models (LLMs) have been shown to be able to perform new tasks
based on a few demonstrations or natural language instructions. While these
capabilities have led to widespread adoption, most LLMs are developed by
resource-rich organizations and are frequently kept from the public. As a step
towards democratizing this powerful technology, we present BLOOM, a
176B-parameter open-access language model designed and built thanks to a
collaboration of hundreds of researchers. BLOOM is a decoder-only Transformer
language model that was trained on the ROOTS corpus, a dataset comprising
hundreds of sources in 46 natural and 13 programming languages (59 in total).
We find that BLOOM achieves competitive performance on a wide variety of
benchmarks, with stronger results after undergoing multitask prompted
finetuning. To facilitate future research and applications using LLMs, we
publicly release our models and code under the Responsible AI License
Non-invasive assessment of adrenocortical activity as a measure of stress in giraffe (Giraffa camelopardalis)
Additional file 1: Full dataset in Microsoft Excel workbook format.BACKGROUND : Numbers of giraffes are declining rapidly in their native habitat. As giraffe research and conservation
efforts increase, the demand for more complete measures of the impact of conservation interventions and the
effects of captive environments on animal health and welfare have risen. We compared the ability of six different
enzyme immunoassays to quantify changes in fecal glucocorticoid metabolites (FGM) resulting from three sources:
adrenocorticotropic hormone stimulation test, transport, and time of day that samples were collected.
RESULTS : Two male giraffes underwent ACTH injections; all six assays detected FGM increases following injection
for Giraffe 1, while only three assays detected FGM increases following injection for Giraffe 2. Consistent with other
ruminant species, the two 11-oxoetiocholanolone assays (one for 11,17-dioxoandrostanes and the other for
3α,11-oxo metabolites) measured the most pronounced and prolonged elevation of FGM, while an assay
for 3ÎČ,11ÎČ-diol detected peaks of smaller magnitude and duration. Both of the 11-oxoetiocholanolone assays
detected significant FGM increases after transport in Giraffes 3â7, and preliminary data suggest FGM detected
by the assay for 11,17-dioxoandrostanes may differ across time of day.
CONCLUSIONS : We conclude the assay for 11,17-dioxoandrostanes is the most sensitive assay tested for FGM
in giraffes and the assay for FGM with a 5ÎČ-3α-ol-11-one structure is also effective. 11-oxoetiocholanolone
enzyme immunoassays have now been demonstrated to be successful in a wide variety of ruminant species,
providing indirect evidence that 5ÎČ-reduction may be a common metabolic pathway for glucocorticoids in
ruminants. As FGM peaks were detected in at least some giraffes using all assays tested, giraffes appear to
excrete a wide variety of different FGM. The assays validated here will provide a valuable tool for research
on the health, welfare, and conservation of giraffes.The Association of Friends and Supporters of Goethe University Frankfurt
provided financial support for F. Sicks to travel to Vienna to analyze fecal
samples and von Opel Hessische Zoostiftung supported a studentship for
F. Sicks. One commercial funder [Tierpark Berlin] provided support in the
form of salary for F. Sicks during data analysis and preparation of this
manuscript. The specific role of this author is articulated in the âAuthor
Contributionsâ section.http://www.biomedcentral.com/bmcvetresam2016Anatomy and PhysiologyParaclinical Science
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