1,774 research outputs found
Social exclusion and land administration in Orissa, India
The authors report on the first empirical study of its kind to examine - from the perspective of transaction costs - factors that constrain access to land for the rural poor and other socially excluded groups in India. They find that: a) Land reform has reduced large landholdings since the 1950s. Medium size farms have gained most. Formidable obstacles still prevent the poor from gaining access to land. b) The complexity of land revenue administration in Orissa is partly the legacy of distinctly different systems, which produced more or less complete and accurate land records. These not-so-distant historical records can be important in resolving contemporary land disputes. c) Orissa tried legally to abolish land-leasing. Concealed tenancy persisted, with tenants having little protection under the law. d) Women's access to and control over land, and their bargaining power with their husbands about land, may be enhanced through joint land titling, a principle yet to be realized in Orissa. e) Land administration is viewed as a burden on the state rather than a service, and land records and registration systems are not coordinated. Doing so will improve rights for the poor and reduce transaction costs - but only if the system is transparent and the powerful do not retain the leverage over settlement officers that has allowed land grabs. Land in Orissa may be purchased, inherited, rented (leased), or - in the case of public land and the commons - encroached upon. Each type of transaction - and the State's response, through land law and administration - has implications for poor people's access to land. The authors find that: 1) Land markets are thin and transaction costs are high, limiting the amount of agricultural land that changes hands. 2) The fragmentation of landholdings into tiny, scattered plots is a brake on agricultural productivity, but efforts to consolidate land may discriminate against the rural poor. Reducing transaction costs in land markets will help. 3) Protecting the rural poor's rights of access to common land requires raising public awareness and access to information. 4) Liberalizing land-lease markets for the rural poor will help, but only if the poor are ensured access to institutional credit.Banks&Banking Reform,Public Sector Management and Reform,Environmental Economics&Policies,Land Use and Policies,Urban Governance and Management,Public Sector Management and Reform,Environmental Economics&Policies,Banks&Banking Reform,Rural Land Policies for Poverty Reduction,Land Use and Policies
Embedding calculus knot invariants are of finite type
We show that the map on components from the space of classical long knots to
the n-th stage of its Goodwillie-Weiss embedding calculus tower is a map of
monoids whose target is an abelian group and which is invariant under clasper
surgery. We deduce that this map on components is a finite type-(n-1) knot
invariant. We also compute the second page in total degree zero for the
spectral sequence converging to the components of this tower as Z-modules of
primitive chord diagrams, providing evidence for the conjecture that the tower
is a universal finite-type invariant over the integers. Key to these results is
the development of a group structure on the tower compatible with connect-sum
of knots, which in contrast with the corresponding results for the (weaker)
homology tower requires novel techniques involving operad actions, evaluation
maps, and cosimplicial and subcubical diagrams.Comment: Revised maps to the infinitesimal mapping space model in Sections 3
and 4 and analysis of cubical diagrams in Section 5. Minor expository and
organizational changes throughout. Now 28 pages, 4 figure
Determining the sex of a monomorphic threatened, endemic passerine in the sky islands of southern India using molecular and morphometric methods
Identifying the sex of an individual is often a basic
requirement for many biological studies. This is often
critically important for threatened or endangered
species that may require different conservation strategies
for the two sexes. In many passerine birds, like
the threatened, endemic White-bellied Shortwing,
Brachypteryx albiventris, found only in the Shola forests
of the Western Ghats, however, the sexes are
often monomorphic and indistinguishable in the field.
There has been some conflicting information in the
historic incidental records on how the sexes can be
identified in this species. We conducted molecular sexing
to determine the sexual identity of 99 individuals
captured in the field and examined the possibility of
using some key morphological and morphometric
variables to predict the sex of these individuals. Of all
the variables tested, the sexes could be distinguished
only by the relatively greater wing and tarsus length of the males. We then examined the sexual identity of
149 individuals that were captured over four years of
fieldwork during a long-term study of this species.
This study thus provides important baseline data for
an ongoing exploration of the ecology and demography
of the two sexes of this unique threatened bird
Ancient geographical gaps and paleo-climate shape the Phylogeography of an endemic bird in the sky islands of Southern India
Background
Sky islands, formed by the highest reaches of mountain tracts physically isolated from one another, represent one of the biodiversity-rich regions of the world. Comparative studies of geographically isolated populations on such islands can provide valuable insights into the biogeography and evolution of species on these islands. The Western Ghats mountains of southern India form a sky island system, where the relationship between the island structure and the evolution of its species remains virtually unknown despite a few population genetic studies.
Methods and Principal Findings
We investigated how ancient geographic gaps and glacial cycles have partitioned genetic variation in modern populations of a threatened endemic bird, the White-bellied Shortwing Brachypteryx major, across the montane Shola forests on these islands and also inferred its evolutionary history. We used Bayesian and maximum likelihood-based phylogenetic and population-genetic analyses on data from three mitochondrial markers and one nuclear marker (totally 2594 bp) obtained from 33 White-bellied Shortwing individuals across five islands. Genetic differentiation between populations of the species correlated with the locations of deep valleys in the Western Ghats but not with geographical distance between these populations. All populations revealed demographic histories consistent with population founding and expansion during the Last Glacial Maximum. Given the level of genetic differentiation north and south of the Palghat Gap, we suggest that these populations be considered two different taxonomic species.
Conclusions and Significance
Our results show that the physiography and paleo-climate of this region historically resulted in multiple glacial refugia that may have subsequently driven the evolutionary history and current population structure of this bird. The first avian genetic study from this biodiversity hotspot, our results provide insights into processes that may have impacted the speciation and evolution of the endemic fauna of this region
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FORTE 2.0: a fast, parallel and flexible coupled climate model
FORTE 2.0 is an intermediate-resolution coupled atmosphere–ocean general circulation model (AOGCM) consisting of the Intermediate General Circulation Model 4 (IGCM4), a T42 spectral atmosphere with 35σ layers, coupled to Modular Ocean Model – Array (MOMA), a 2∘ × 2∘ ocean with 15 z-layer depth levels. Sea ice is represented by a simple flux barrier. Both the atmosphere and ocean components are coded in Fortran. It is capable of producing a stable climate for long integrations without the need for flux adjustments. One flexibility afforded by the IGCM4 atmosphere is the ability to configure the atmosphere with either 35σ layers (troposphere and stratosphere) or 20σ layers (troposphere only). This enables experimental designs for exploring the roles of the troposphere and stratosphere, and the faster integration of the 20σ layer configuration enables longer duration studies on modest hardware. A description of FORTE 2.0 is given, followed by the analysis of two 2000-year control integrations, one using the 35σ configuration of IGCM4 and one using the 20σ configuration
Scientific Opportunities with an X-ray Free-Electron Laser Oscillator
An X-ray free-electron laser oscillator (XFELO) is a new type of hard X-ray
source that would produce fully coherent pulses with meV bandwidth and stable
intensity. The XFELO complements existing sources based on self-amplified
spontaneous emission (SASE) from high-gain X-ray free-electron lasers (XFEL)
that produce ultra-short pulses with broad-band chaotic spectra. This report is
based on discussions of scientific opportunities enabled by an XFELO during a
workshop held at SLAC on June 29 - July 1, 2016Comment: 21 pages, 12 figure
Genome-Wide Studies of Histone Demethylation Catalysed by the Fission Yeast Homologues of Mammalian LSD1
In order to gain a more global view of the activity of histone demethylases, we report here genome-wide studies of the fission yeast SWIRM and polyamine oxidase (PAO) domain homologues of mammalian LSD1. Consistent with previous work we find that the two S. pombe proteins, which we name Swm1 and Swm2 (after SWIRM1 and SWIRM2), associate together in a complex. However, we find that this complex specifically demethylates lysine 9 in histone H3 (H3K9) and both up- and down-regulates expression of different groups of genes. Using chromatin-immunoprecipitation, to isolate fragments of chromatin containing either H3K4me2 or H3K9me2, and DNA microarray analysis (ChIP-chip), we have studied genome-wide changes in patterns of histone methylation, and their correlation with gene expression, upon deletion of the swm1+ gene. Using hyper-geometric probability comparisons we uncover genetic links between lysine-specific demethylases, the histone deacetylase Clr6, and the chromatin remodeller Hrp1. The data presented here demonstrate that in fission yeast the SWIRM/PAO domain proteins Swm1 and Swm2 are associated in complexes that can remove methyl groups from lysine 9 methylated histone H3. In vitro, we show that bacterially expressed Swm1 also possesses lysine 9 demethylase activity. In vivo, loss of Swm1 increases the global levels of both H3K9me2 and H3K4me2. A significant accumulation of H3K4me2 is observed at genes that are up-regulated in a swm1 deletion strain. In addition, H3K9me2 accumulates at some genes known to be direct Swm1/2 targets that are down-regulated in the swm1¿ strain. The in vivo data indicate that Swm1 acts in concert with the HDAC Clr6 and the chromatin remodeller Hrp1 to repress gene expression. In addition, our in vitro analyses suggest that the H3K9 demethylase activity requires an unidentified post-translational modification to allow it to act. Thus, our results highlight complex interactions between histone demethylase, deacetylase and chromatin remodelling activities in the regulation of gene expression
Исследования гидравлических сопротивлений при движении в трубах золошлаковых тампонажно- закладочных суспензий
Експериментально досліджено залежність гідравлічного опору від швидкості руху та
концентрації золошлакових суспензій при течії по трубах. Встановлена критична швидкість
руху концентрованих гідросумішей.Dependence of hydraulic resistance is experimentally set from the rate of movement of ash-slag suspensions at a flow on pipes. The critical speed of motion of the concentrated slurries is set
A nucleosome turnover map reveals that the stability of histone H4 Lys20 methylation depends on histone recycling in transcribed chromatin
Nucleosome composition actively contributes to chromatin structure and accessibility. Cells have developed mechanisms to remove or recycle histones, generating a landscape of differentially aged nucleosomes. This study aimed to create a high-resolution, genome-wide map of nucleosome turnover in Schizosaccharomyces pombe. The recombination-induced tag exchange (RITE) method was used to study replication-independent nucleosome turnover through the appearance of new histone H3 and the disappearance or preservation of old histone H3. The genome-wide location of histones was determined by chromatin immunoprecipitation–exonuclease methodology (ChIP-exo). The findings were compared with diverse chromatin marks, including histone variant H2A.Z, post-translational histone modifications, and Pol II binding. Finally, genome-wide mapping of the methylation states of H4K20 was performed to determine the relationship between methylation (mono, di, and tri) of this residue and nucleosome turnover. Our analysis showed that histone recycling resulted in low nucleosome turnover in the coding regions of active genes, stably expressed at intermediate levels. High levels of transcription resulted in the incorporation of new histones primarily at the end of transcribed units. H4K20 was methylated in low-turnover nucleosomes in euchromatic regions, notably in the coding regions of long genes that were expressed at low levels. This transcription-dependent accumulation of histone methylation was dependent on the histone chaperone complex FACT. Our data showed that nucleosome turnover is highly dynamic in the genome and that several mechanisms are at play to either maintain or suppress stability. In particular, we found that FACT-associated transcription conserves histones by recycling them and is required for progressive H4K20 methylation
Identification of vaccine targets & design of vaccine against SARS-CoV-2 coronavirus using computational and deep learning-based approaches
An unusual pneumonia infection, named COVID-19, was reported on December 2019 in China. It was reported to be caused by a novel coronavirus which has infected approximately 220 million people worldwide with a death toll of 4.5 million as of September 2021. This study is focused on finding potential vaccine candidates and designing an in-silico subunit multi-epitope vaccine candidates using a unique computational pipeline, integrating reverse vaccinology, molecular docking and simulation methods. A protein named spike protein of SARS-CoV-2 with the GenBank ID QHD43416.1 was shortlisted as a potential vaccine candidate and was examined for presence of B-cell and T-cell epitopes. We also investigated antigenicity and interaction with distinct polymorphic alleles of the epitopes. High ranking epitopes such as DLCFTNVY (B cell epitope), KIADYNKL (MHC Class-I) and VKNKCVNFN (MHC class-II) were shortlisted for subsequent analysis. Digestion analysis verified the safety and stability of the shortlisted peptides. Docking study reported a strong binding of proposed peptides with HLA-A*02 and HLA-B7 alleles. We used standard methods to construct vaccine model and this construct was evaluated further for its antigenicity, physicochemical properties, 2D and 3D structure prediction and validation. Further, molecular docking followed by molecular dynamics simulation was performed to evaluate the binding affinity and stability of TLR-4 and vaccine complex. Finally, the vaccine construct was reverse transcribed and adapted for E. coli strain K 12 prior to the insertion within the pET-28-a (+) vector for determining translational and microbial expression followed by conservancy analysis. Also, six multi-epitope subunit vaccines were constructed using different strategies containing immunogenic epitopes, appropriate adjuvants and linker sequences. We propose that our vaccine constructs can be used for downstream investigations using in-vitro and in-vivo studies to design effective and safe vaccine against different strains of COVID-19
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