2,631 research outputs found
BioLPG for Clean Cooking in Sub-Saharan Africa: Present and Future Feasibility of Technologies, Feedstocks, Enabling Conditions and Financing
Energy supply for clean cooking is a priority for Sub-Saharan Africa (SSA). Liquefied petroleum gas (LPG, i.e., propane or butane or a mixture of both) is an economically efficient, cooking energy solution used by over 2.5 billion people worldwide and scaled up in numerous low- and middle-income countries (LMICs). Investigation of the technical, policy, economic and physical requirements of producing LPG from renewable feedstocks (bioLPG) finds feasibility at scale in Africa. Biogas and syngas from the circular economic repurposing of municipal solid waste and agricultural waste can be used in two groundbreaking new chemical processes (Cool LPG or Integrated Hydropyrolysis and Hydroconversion (IH2)) to selectively produce bioLPG. Evidence about the nature and scale potential of bioLPG presented in this study justifies further investment in the development of bioLPG as a fuel that can make a major contribution toward enabling an SSA green economy and universal energy access. Techno-economic assessments of five potential projects from Ghana, Kenya and Rwanda illustrate what might be possible. BioLPG technology is in the early days of development, so normal technology piloting and de-risking need to be undertaken. However, fully developed bioLPG production could greatly reduce the public and private sector investment required to significantly increase SSA clean cooking capacity
Oxygen: A Fundamental Property Regulating Pelagic Ecosystem Structure in the Coastal Southeastern Tropical Pacific
Background: In the southeastern tropical Pacific anchovy (Engraulis ringens) and sardine (Sardinops sagax) abundance have recently fluctuated on multidecadal scales and food and temperature have been proposed as the key parameters explaining these changes. However, ecological and paleoecological studies, and the fact that anchovies and sardines are favored differently in other regions, raise questions about the role of temperature. Here we investigate the role of oxygen in structuring fish populations in the Peruvian upwelling ecosystem that has evolved over anoxic conditions and is one of the world's most productive ecosystems in terms of forage fish. This study is particularly relevant given that the distribution of oxygen in the ocean is changing with uncertain consequences. Methodology/Principal Findings: A comprehensive data set is used to show how oxygen concentration and oxycline depth affect the abundance and distribution of pelagic fish. We show that the effects of oxygen on anchovy and sardine are opposite. Anchovy flourishes under relatively low oxygen conditions while sardine avoid periods/areas with low oxygen concentration and restricted habitat. Oxygen consumption, trophic structure and habitat compression play a fundamental role in fish dynamics in this important ecosystem. Conclusions/Significance: For the ocean off Peru we suggest that a key process, the need to breathe, has been neglected previously. Inclusion of this missing piece allows the development of a comprehensive conceptual model of pelagic fish populations and change in an ocean ecosystem impacted by low oxygen. Should current trends in oxygen in the ocean continue similar effects may be evident in other coastal upwelling ecosystems
State of poeciliid fishes in the international market
Objective: To make a review about the knowledge of the fish of the family poecilidade in Mexico in the main areas of knowledge.
Design/methodology/approach: The present review was carried out through the search and bibliographic compilation of literature, as well as in the consultation of articles in different databases, for its subsequent analysis.
Results: Poeciliid fish are the most widespread group of ornamental fish internationally, they are found in all international markets, leading productions for aquarium purposes, and therefore have great economic importance within the trade of aquatic organisms for commercial purposes. Ornamental.
Limitations on study/implications: The Poeciliids are a well-known group of fish, however information on marketing and specific sales data is limited.
Findings/conclusions: The most sold fish is the Guppy (P. reticulata), followed by mollies, platies and swordtails, which constitute the main internationally traded poeciliids.Objetivo: Hacer una revisión y análisis acerca del papel que tienen los peces poecílidos dentro del mercado internacional.
Diseño/metodología/aproximación: La presente investigación se realizó mediante la búsqueda y recopilación bibliográfica de literatura, así como en la consulta de artículos en diferentes bases de datos, para su posterior análisis y procesamiento de la información.
Resultados: Los peces poecílidos son el grupo de peces ornamentales más extendido a nivel internacional, se encuentran en todos los mercados internacionales, liderando las producciones con fines de acuariofilia, por lo que tienen gran importancia económica dentro del comercio de organismos acuáticos con fines ornamentales
Limitaciones del estudio/implicaciones: Los poecílidos son un grupo de peces bien conocido, sin embargo, la información sobre comercialización y datos específicos de venta se encuentra limitado.
Hallazgos/conclusiones: El pez más vendido es el Guppy (P. reticulata), seguido de los mollies, platies y colas de espada, los cuales constituyen los principales poecílidos comercializados a nivel internacional
Drosophila Insulin Pathway Mutants Affect Visual Physiology and Brain Function Besides Growth, Lipid, and Carbohydrate Metabolism
OBJECTIVE—Type 2 diabetes is the most common form of diabetes worldwide. Some of its complications, such as retinop-athy and neuropathy, are long-term and protracted, with an un-clear etiology. Given this problem, genetic model systems, such as in flies where type 2 diabetes can be modeled and studied, offer distinct advantages. RESEARCH DESIGN AND METHODS—We used individual flies, control, and mutant individuals with partial loss-of-function insulin pathway genes. We measured wing size and tested body weight for growth phenotypes, the latter by means of a microbal-ance. We studied total lipid and carbohydrate content, lipids by a reaction in single fly homogenates with vanillin-phosphoric acid, and carbohydrates with an anthrone-sulfuric acid reaction. Cholinesterase activity was measured using the Ellman method in head homogenates from pooled fly heads, and electroretinogram
Testing Meson Portal Dark Sector Solutions to the MiniBooNE Anomaly at CCM
A solution to the MiniBooNE excess invoking rare three-body decays of the
charged pions and kaons to new states in the MeV mass scale was recently
proposed as a dark-sector explanation. This class of solution illuminates the
fact that, while the charged pions were focused in the target-mode run, their
decay products were isotropically suppressed in the beam-dump-mode run in which
no excess was observed. This suggests a new physics solution correlated to the
mesonic sector. We investigate an extended set of phenomenological models that
can explain the MiniBooNE excess as a dark sector solution, utilizing
long-lived particles that might be produced in the three-body decays of the
charged mesons and the two-body anomalous decays of the neutral mesons. Over a
broad set of interactions with the long-lived particles, we show that these
scenarios can be compatible with constraints from LSND, KARMEN, and MicroBooNE,
and evaluate the sensitivity of the ongoing and future data taken by the
Coherent CAPTAIN Mills experiment (CCM) to a potential discovery in this
parameter space.Comment: 15 pages, 14 figures. Planned submission for PR
A search for point sources of EeV photons
Measurements of air showers made using the hybrid technique developed with
the fluorescence and surface detectors of the Pierre Auger Observatory allow a
sensitive search for point sources of EeV photons anywhere in the exposed sky.
A multivariate analysis reduces the background of hadronic cosmic rays. The
search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an
energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been
detected. An upper limit on the photon flux has been derived for every
direction. The mean value of the energy flux limit that results from this,
assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial
direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in
which EeV cosmic ray protons are emitted by non-transient sources in the
Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical
Journa
Reconstruction of inclined air showers detected with the Pierre Auger Observatory
We describe the method devised to reconstruct inclined cosmic-ray air showers
with zenith angles greater than detected with the surface array of
the Pierre Auger Observatory. The measured signals at the ground level are
fitted to muon density distributions predicted with atmospheric cascade models
to obtain the relative shower size as an overall normalization parameter. The
method is evaluated using simulated showers to test its performance. The energy
of the cosmic rays is calibrated using a sub-sample of events reconstructed
with both the fluorescence and surface array techniques. The reconstruction
method described here provides the basis of complementary analyses including an
independent measurement of the energy spectrum of ultra-high energy cosmic rays
using very inclined events collected by the Pierre Auger Observatory.Comment: 27 pages, 19 figures, accepted for publication in Journal of
Cosmology and Astroparticle Physics (JCAP
The Pierre Auger Observatory: Contributions to the 34th International Cosmic Ray Conference (ICRC 2015)
Contributions of the Pierre Auger Collaboration to the 34th International
Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The NetherlandsComment: 24 proceedings, the 34th International Cosmic Ray Conference, 30 July
- 6 August 2015, The Hague, The Netherlands; will appear in PoS(ICRC2015
Measurement of χ c1 and χ c2 production with s√ = 7 TeV pp collisions at ATLAS
The prompt and non-prompt production cross-sections for the χ c1 and χ c2 charmonium states are measured in pp collisions at s√ = 7 TeV with the ATLAS detector at the LHC using 4.5 fb−1 of integrated luminosity. The χ c states are reconstructed through the radiative decay χ c → J/ψγ (with J/ψ → μ + μ −) where photons are reconstructed from γ → e + e − conversions. The production rate of the χ c2 state relative to the χ c1 state is measured for prompt and non-prompt χ c as a function of J/ψ transverse momentum. The prompt χ c cross-sections are combined with existing measurements of prompt J/ψ production to derive the fraction of prompt J/ψ produced in feed-down from χ c decays. The fractions of χ c1 and χ c2 produced in b-hadron decays are also measured
Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC
The uncertainty on the calorimeter energy response to jets of particles is
derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the
calorimeter response to single isolated charged hadrons is measured and
compared to the Monte Carlo simulation using proton-proton collisions at
centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009
and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter
response to specific types of particles (positively and negatively charged
pions, protons, and anti-protons) is measured and compared to the Monte Carlo
predictions. Finally, the jet energy scale uncertainty is determined by
propagating the response uncertainty for single charged and neutral particles
to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3%
for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table,
submitted to European Physical Journal
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