583 research outputs found
Land-related conflicts in Sub-Saharan Africa
Sub-Saharan Africa has a history of land dispossession and contestation which have resulted in various types of inequalities and a skewed distribution of land resources. Land in Sub-Saharan Africa has been subject to conflict, conquest, expropriation and exploitation thus resulting in the many discrepancies that exist today. This has greatly influenced the socio-economic and political positions of different groups of people. This situation has resulted in numerous land conflicts, and in most Sub-Saharan countries the land question and past inequalities remain unresolved. This article shows that there are various types of land conflicts in Sub-Saharan Africa. Furthermore, land conflicts are generally influenced by a range of complex and interrelated factors. Specifically, aspects relating to poverty and inequality as well as land reformation processes arerelevant given that contestations over land resources are most noticeable among the poor. Additionally, land conflicts are intensifying and becoming more widespread. The article also discusses key aspects that need to be considered when managing land conflicts. It is important to note that this article draws heavily on a South African perspective and is not an exhaustive review of the range of land-related conflicts on a diverse continent where significant variations exist. The focus is on highlighting key aspects and identifying commonalities
Environmental conflicts: Key issues and management implications
Environmental conflicts have emerged as key issues challenging local, regional, national and global security. Environmental crises and problems throughout the world are widespread and increasing rapidly. In relation to these concerns, the article discusses the following aspects: people and the environment, environmental conflicts, climate change and environmental conflicts, and management implications. The section on people and the environment illustrates the range of ecosystems services provided, interactions, relationships and issues pertaining to access. Specific key types of conflicts as well as the main manifestations and implications of these conflicts are examined in the next section, which includes biodiversity, environmental air quality, forestry, water, land and natural resource management conflicts. This is followed by a discussion of the impacts of climate change in relation to environmental conflicts. Finally, the discussion focuses on managing environmental conflicts. Key aspects of the final section pertain to available tools and approaches, and recommendations arising from the articles in this issue
Sustainable Ecotourism Management in Kenya
The study of ecotourism impacts and their management offers many opportunities to reflect on the importance of sustainability and the possibilities of implementing approaches which move us in a new direction.Sustainability, then, is about the struggle for diversity in all its dimensions. The concern for biodiversity, in its broadest sense, encompasses not only threatened flora and fauna, but also the survivability of these humancommunities, as stewards of the natural environment and as producers. The research which adopts both quantitative and qualitative approaches, reports on the few attempts to identify ecotourism impacts and theirmanagement from the perspectives of all the stakeholders concerned which includes the visitors, tour operators, accommodation outlets, local community and Park and Reserve Management. The findings of thisresearch therefore have implications for conservation management from the ecotourism point of view as well as an enhanced sustainable community development in Amboseli National Park and Masai Mara National Reserve.Key Words: Amboseli, Ecotourism, Management, Masai Mara, Sustainabl
Light Neutralino Dark Matter in the NMSSM
Neutralino dark matter is generally assumed to be relatively heavy, with a
mass near the electroweak scale. This does not necessarily need to be the case,
however. In the Next-to-Minimal Supersymmetric Standard Model (NMSSM) and other
supersymmetric models with an extended Higgs sector, a very light CP-odd Higgs
boson can naturally arise making it possible for a very light neutralino to
annihilate efficiently enough to avoid being overproduced in the early
Universe.
In this article, we explore the characteristics of a supersymmetric model
needed to include a very light neutralino, 100 MeV < \mcnone < 20 GeV, using
the NMSSM as a prototype. We discuss the most important constraints from
Upsilon decays, , and the magnetic moment
of the muon, and find that a light bino or singlino neutralino is allowed, and
can be generated with the appropriate relic density.
It has previously been shown that the positive detection of dark matter
claimed by the DAMA collaboration can be reconciled with other direct dark
matter experiments such as CDMS II if the dark matter particle is rather light,
between about 6 and 9 GeV. A singlino or bino-like neutralino could easily fall
within this range of masses within the NMSSM. Additionally, models with sub-GeV
neutralinos may be capable of generating the 511 keV gamma-ray emission
observed from the galactic bulge by the INTEGRAL/SPI experiment.
We also point out measurements which can be performed immediately at CLEO,
BaBar and Belle using existing data to discover or significantly constrain this
scenario.Comment: References updated, accepted for publication in PR
The Higgs Sector in a Extension of the MSSM
We consider the Higgs sector in an extension of the MSSM with extra SM
singlets, involving an extra gauge symmetry, in which the
domain-wall problem is avoided and the effective parameter is decoupled
from the new gauge boson mass. The model involves a rich Higgs
structure very different from that of the MSSM. In particular, there are large
mixings between Higgs doublets and the SM singlets, significantly affecting the
Higgs spectrum, production cross sections, decay modes, existing exclusion
limits, and allowed parameter range. Scalars considerably lighter than the LEP2
bound (114 GeV) are allowed, and the range is both allowed
and theoretically favored. Phenomenologically, we concentrate our study on the
lighter (least model-dependent, yet characteristic) Higgs particles with
significant SU(2)-doublet components to their wave functions, for the case of
no explicit CP violation in the Higgs sector. We consider their spectra,
including the dominant radiative corrections to their masses from the top/stop
loop. We computed their production cross sections and reexamine the existing
exclusion limits at LEP2. We outline the searching strategy for some
representative scenarios at a future linear collider. We emphasize that
gaugino, Higgsino, and singlino decay modes are indicative of extended models
and have been given little attention. We present a comprehensive list of model
scenarios in the Appendices.Comment: 49 pages, 17 figure
Modeling the behavior of heat-shrinkable thin films
We describe an asymptotic model for the behavior of PET-like heat-shrinkable thin films that includes both membrane and bending energies when the thickness of the film is positive. We compare the model to Koiter’s shell model and to models in which a membrane energy or a bending energy are obtained by Γ-convergence techniques. We also provide computational results for various temperature distributions applied to the films
Radion effects on unitarity in gauge-boson scattering
The scalar field associated with fluctuations in the positions of the two
branes, the ``radion'', plays an important role determining the cosmology and
collider phenomenology of the Randall-Sundrum solution to the hierarchy
problem. It is now well known that the radion mass is of order the weak scale,
and that its couplings to standard model fields are order 1/TeV to the trace of
the energy momentum tensor. We calculate longitudinal vector boson scattering
amplitudes to explore the constraints on the radion mass and its coupling from
perturbative unitarity. The scattering cross section can indeed become
non-perturbative at energies prior to reaching the TeV brane cutoff scale, but
only when some curvature-Higgs mixing on the TeV brane is present. We show that
the coefficient of the curvature-Higgs mixing operator must be less than about
3 for the 4-d effective theory to respect perturbative unitarity up to the TeV
brane cutoff scale. Mass bounds on the Higgs boson and the radion are also
discussed.Comment: 17 pages, LaTeX, 5 eps figures, uses epsf.sty and axodraw.st
Generation of an induced pluripotent stem cell line (MHHi018-A) from a patient with Cystic Fibrosis carrying p.Asn1303Lys (N1303K) mutation
Cystic Fibrosis (CF) is a genetic disease caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene which encodes for a chloride ion channel regulating the balance of salt and water across secretory epithelia. Here we generated an iPSC line from a CF patient homozygous for the p.Asn1303Lys mutation, a Class II folding defect mutation. This iPSC line provides a useful resource for disease modeling and to investigate the pharmacological response to CFTR modulators in iPSC derived epithelia
Effects of genuine dimension-six Higgs operators
We systematically discuss the consequences of genuine dimension-six Higgs
operators. These operators are not subject to stringent constraints from
electroweak precision data. However, they can modify the couplings of the Higgs
boson to electroweak gauge bosons and, in particular, the Higgs
self-interactions. We study the sensitivity to which those couplings can be
probed at future \ee linear colliders in the sub-TeV and in the multi-TeV
range. We find that for GeV with a luminosity of 1 ab the
anomalous and couplings may be probed to about the 0.01 level, and
the anomalous coupling to about the 0.1 level.Comment: 21 pages, 17 figures; typos corrected and references adde
Mate choice in a polluted world: consequences for individuals, populations and communities
Pollution (e.g. by chemicals, noise, light, heat) is an insidious consequence of anthropogenic activity that affects environments worldwide. Exposure of wildlife to pollutants has the capacity to adversely affect animal communication and behaviour across a wide range of sensory modalities-by not only impacting the signalling environment, but also the way in which animals produce, perceive and interpret signals and cues. Such disturbances, particularly when it comes to sex, can drastically alter fitness. Here, we consider how pollutants disrupt communication and behaviour during mate choice, and the ecological and evolutionary changes such disturbances can engender. We explain how the different stages of mate choice can be affected by pollution, from encountering mates to the final choice, and how changes to these stages can influence individual fitness, population dynamics and community structure. We end with discussing how an understanding of these disturbances can help inform better conservation and management practices and highlight important considerations and avenues for future research. This article is part of the theme issue 'Linking behaviour to dynamics of populations and communities: application of novel approaches in behavioural ecology to conservation'.Peer reviewe
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