863 research outputs found
Use of relevant economic indicators for the evaluation of farming systems in terms of viability, resilience, vulnerability and sustainability: the case of the Lake Alaotra region in Madagascar
The WAW initiative (World Agricultures Watch) intends to elaborate a worldwide observatory collecting information on agriculture in different countries and its evolution. Madagascar has been chosen as one of the pilot countries. The geographical area of the study which has been chosen is the lake Alaotra. The study of the notions of vulnerability, resilience, durability and viability has been the main point concerning the choice, the calculation and the analysis of the necessary indicators leading to the elaboration of the observatory. Three different data lines have been chosen: i) The database from the ROR, with annual data from 2005 to 2008 for 500 households ii) The database from the agricultural diagnosis BV-Lac in 2007 (110 farms) and iii) The database from RFR, with 48 farms in 2009 . This paper presents some results with farming systems modeling using the two databases from the BV-lac development project showing the indicators used through the example of a technical change with adoption of conservation agriculture
Use of relevant economical indicators for the evaluation of farming systems in terms of resilience, vulnerability and sustainability: the case of the Lake Alaotra region in Madagascar
The project Observatory for World Agricultures wants to elaborate a worldwide observatory collecting information on agriculture in different countries and its evolution. At the moment five countries have been chosen as countries of reference, Madagascar is one of them. The geographical area of the study which has been chosen is the lake Alaotra. The study of the notions of vulnerability, resilience, durability and viability has been the main point concerning the choice, the calculation and the analysis of the necessary indicators leading to the elaboration of the observatory. Three different data lines have been chosen : i) The database from the ROR, ii) The database from RFR and iii) The database from the agricultural diagnosis Bv-Lac (Durand, Nave & Penot). This paper presents some results with farming systems modeling using the two databases from the BVlac development project showing the indicators used through the example of a technical change with adoption of conservation agriculture
A systematic review of treating recurrent head and neck cancer: a reintroduction of brachytherapy with or without surgery.
Purpose: To review brachytherapy use in recurrent head and neck carcinoma (RHNC) with focus on its efficacy and complication rates.
Material and methods: A literature search of PubMed, Ovid, Google Scholar, and Scopus was conducted from 1990 to 2017. Publications describing treatment of RHNC with brachytherapy with or without surgery were included. The focus of this review is on oncologic outcomes and the safety of brachytherapy in the recurrent setting.
Results: Thirty studies involving RHNC treatment with brachytherapy were reviewed. Brachytherapy as adjunctive treatment to surgical resection appears to be associated with an improved local regional control and overall survival, when compared with the published rates for re-irradiation utilizing external beam radiotherapy (RT) or brachytherapy alone. Safety data remains variable with different isotopes and dose rates with implantable brachytherapy demonstrating a tolerable side effect profile.
Conclusions: Although surgery remains a mainstay treatment for RHNC, intraoperative interstitial brachytherapy delivery as adjunctive therapy may improve the treatment outcome and may be associated with fewer complication rates as compared to reirradiation using external beam radiotherapy. Further investigations are required to elucidate the role of brachytherapy for RHNC
Long COVID: Is there a kidney link?
Metabolic causes such as altered bioenergetics and amino acid metabolism may play a major role in Long COVID. Renal-metabolic regulation is an integral part of these pathways but has not been systematically or routinely investigated in Long COVID. Here we discuss the biochemistry of renal tubular injury as it may contribute to Long COVID symptoms. We propose three potential mechanisms that could be involved in Long COVID namely creatine phosphate metabolism, un-reclaimed glomerular filtrate and COVID specific proximal tubule cells (PTC) injury-a tryptophan paradigm. This approach is intended to allow for improved diagnostics and therapy for the long-haul sufferers
Extended Friedberg Lee hidden symmetries, quark masses and CP-violation with four generations
Motivated in part by the several observed anomalies involving CP asymmetries
of B and B_s decays, we consider the Standard Model with a 4th sequential
family (SM4) which seems to offer a rather simple resolution. We initially
assume T-invariance by taking the up and down-quark 4x4 mass matrix to be real.
Following Friedberg and Lee (FL), we then impose a "hidden" symmetry on the
unobserved ("hidden") up and down-quark SU(2) states. The hidden symmetry for
four generations ensures the existence of two zero-mass eigenstates, which we
take to be the (u,c) and (d,s) states in the up and down-quark sectors,
respectively. Then, we simultaneously break T-invariance and the hidden
symmetry by introducing two phase factors in each sector. This breaking
mechanism generates the small quark masses m_u, m_c and m_d, m_s which, along
with the orientation of the hidden symmetry, determine the size of CP-violation
in the SM4. For illustration we choose a specific physical picture for the
hidden symmetry and the breaking mechanism that reproduces the observed quark
masses, mixing angles and CP-violation, and at the same time allows us to
further obtain very interesting relations/predictions for the mixing angles of
t and t'. For example, with this choice we get V_{td} ~ (V_{cb}/V_{cd} -
V_{ts}/V_{us}) + O(\lambda^2) and V_{t'b} ~ V_{t'd}x(V_{cb}/V_{cd}), V_{tb'} ~
V_{t'd}x(V_{ts}/V_{us}), implying that V_{t'd} > V_{t'b},V_{tb'}. We
furthermore find that the Cabibbo angle is related to the orientation of the
hidden symmetry and that the key CP-violating quantity of our model at
high-energies, J_{SM4} = Im[V_{tb} V_{t'b}^* V_{t'b'} V_{tb'}^*], which is the
high-energy analogue of the Jarlskog invariant of the SM, is proportional to
the light-quark masses and the measured CKM angles.Comment: 19 page
CP Nonconservation in at the Tevatron
The reaction is found to be rather rich in exhibiting
several different types of CP asymmetries. The spin of the top quark plays an
important role. Asymmetries are related to form factors arising from radiative
corrections of the production vertex due to non-standard physics. As
illustrations, effects are studied in two Higgs Doublet Models and in
Supersymmetric Models; asymmetries up to a few percent may be possible.Comment: 14 pages, 3 figures. Note: replaced due to minor problems that
appeared on some postscript previewers. No change in conten
Accelerating Bayesian hierarchical clustering of time series data with a randomised algorithm
We live in an era of abundant data. This has necessitated the development of new and innovative statistical algorithms to get the most from experimental data. For example, faster algorithms make practical the analysis of larger genomic data sets, allowing us to extend the utility of cutting-edge statistical methods. We present a randomised algorithm that accelerates the clustering of time series data using the Bayesian Hierarchical Clustering (BHC) statistical method. BHC is a general method for clustering any discretely sampled time series data. In this paper we focus on a particular application to microarray gene expression data. We define and analyse the randomised algorithm, before presenting results on both synthetic and real biological data sets. We show that the randomised algorithm leads to substantial gains in speed with minimal loss in clustering quality. The randomised time series BHC algorithm is available as part of the R package BHC, which is available for download from Bioconductor (version 2.10 and above) via http://bioconductor.org/packages/2.10/bioc/html/BHC.html. We have also made available a set of R scripts which can be used to reproduce the analyses carried out in this paper. These are available from the following URL. https://sites.google.com/site/randomisedbhc/
Discovering transcriptional modules by Bayesian data integration
Motivation: We present a method for directly inferring transcriptional modules (TMs) by integrating gene expression and transcription factor binding (ChIP-chip) data. Our model extends a hierarchical Dirichlet process mixture model to allow data fusion on a gene-by-gene basis. This encodes the intuition that co-expression and co-regulation are not necessarily equivalent and hence we do not expect all genes to group similarly in both datasets. In particular, it allows us to identify the subset of genes that share the same structure of transcriptional modules in both datasets.
Results: We find that by working on a gene-by-gene basis, our model is able to extract clusters with greater functional coherence than existing methods. By combining gene expression and transcription factor binding (ChIP-chip) data in this way, we are better able to determine the groups of genes that are most likely to represent underlying TMs
Candidates for HyperCharge Axion in Extensions of the Standard Model
Many theoretically well-motivated extensions of the Standard Model contain
heavy pseudoscalars that couple to hypercharge topological density. The
cosmological dynamics of such hypercharge axions could, under certain
conditions, lead to generation of a net baryon number in a sufficient amount to
explain the observed baryon asymmetry in the universe. We examine the Minimal
Supersymmetric Standard Model and string/M-theory models and determine specific
conditions which heavy axion-like pseudoscalars must satisfy to successfully
drive baryogenesis. We find that all candidates in the Minimal Supersymmetric
Standard Model fail to obey some of the constraints, and that only in special
string/M-theory models some axions may be adequate.Comment: 18 pages, 1 figure, uses axodra
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