460 research outputs found
Invirtiendo en capital natural: un marco para integrar la sostenibilidad ambiental en las polÃticas de cooperación
Tomando en cuenta la magnitud de la crisis ambiental que afecta al planeta y los estrechos vÃnculos existentes entre la conservación de los ecosistemas y la lucha contra la pobreza, cabrÃa preguntarse por qué los temas de protección del medio ambiente continúan teniendo un peso relativo tan bajo en las agendas y prioridades de las agencias de cooperación internacional. En este artÃculo, se analizan las razones de este desequilibrio y se propone un marco conceptual con base socio-ecológica para facilitar una verdadera integración de la sostenibilidad ambiental como prioridad estratégica en las polÃticas y herramientas de ayuda oficial al desarrollo. Varios paradigmas y principios fundamentales emanan de este nuevo marco conceptual, que considera a los ecosistemas funcionales como un capital natural que, adecuadamente gestionado, es capaz de producir un rico y variado flujo de servicios sobre los cuales es posible construir un proceso de desarrollo social, económica y ambientalmente sostenible, además de justo en términos de equidad intra e intergeneracional
Acute generalized, widespread bleeding. Diagnosis and management
BACKGROUND AND OBJECTIVE: Acute generalized, widespread bleeding is often related to disseminated intravascular coagulation (DIC), a pathologic process which complicates the clinical course of many diseases and is characterized by huge amounts of thrombin and plasmin within the circulation. The final result is the consumption of platelets, coagulation factors and inhibitors, as well as secondary hyperfibrinolysis, all leading to diffuse hemorrhage and microthromboses. This review article examines the present attitudes to the diagnosis and treatment of overt DIC in clinical practice, emphasizing the importance of an accurate differential diagnosis from some other processes characterized by acute generalized, widespread bleeding.
INFORMATION SOURCES: The authors have been working in this field, both at experimental and clinical levels, contributing original papers for many years. In addition, material examined in this review includes articles published in journals covered by MedLine, recent reviews in journals with high impact factor and in relevant books on hemostasis and thrombosis.
STATE OF ART AND PERSPECTIVES: DIC is an intermediary mechanism of disease which complicates the clinical course of many well-known disorders. Although the systemic hemorrhagic syndrome is the predominant clinical manifestation, massive intravascular thrombosis frequently occurs contributing to ischemia and associated organ damage, making the mortality rate of this condition high. Current concepts on the pathophysiology, laboratory diagnosis and management of DIC are presented. Complex pathophysiological interrelations make the diagnosis of the etiology of the DIC difficult in clinical practice, although simple tests are useful for identification of patients with the process. Laboratory diagnosis of DIC is mainly based on screening assays, which allow a rapid diagnosis, whereas some other highly sensitive but more complex assays are not always available to routine clinical laboratories. The management of DIC is based on the treatment of the underlying disease, supportive and replacement therapies and the control of the coagulation mechanisms. Although some advances have been achieved, management decisions are still controversial, so that therapy should be highly individualized depending on the nature of the DIC and severity of clinical symptoms. Many syndromes sharing common findings with DIC, such as primary hyperfibrinolysis or thrombotic thrombocytopenic purpura, should be excluded. Finally, new therapeutic approaches to the management of this potentially catastrophic syndrome are require
Floquet stability analysis of a two-layer oscillatory flow near a flexible wall
We investigate the linear Floquet stability of two fluid layers undergoing oscillations
in the direction parallel to the flexible wall that separates them. This canonical
configuration is inspired by the cerebrospinal fluid flow in the spinal canal of subjects with
hydromyelia/syringomyelia. The analysis focuses on the marginal conditions for the onset
of instability, and how these depend on the spatial wavelength of the perturbation, and
on the values of the control parameters, which are the two channel widths, the Reynolds
number and the wall stiffness. Unstable perturbations are found to oscillate synchronous
with the base flow. The wavelength of the most unstable perturbation, of the order of the
stroke length of the basic oscillatory motion, depends strongly on the wall stiffness, but is
only weakly influenced by the channel widths and the Reynolds number. In general, around
criticality, it was found that increasing the Reynolds number has a destabilizing effect, and
that decreasing the canal widths stabilizes the instability. The wall stiffness on the other
hand has a non-monotonic effect, exhibiting an intermediate value for which the instability
is maximally amplified. The present analysis is a first step towards a better understanding
of the physical mechanisms that govern many (bio)fluid mechanical problems that involve
oscillatory flows near compliant walls.Coordinated project, PID2020-115961RB-C31, PID2020-115961RBC32
and PID2020-115961RA-C33, financed by MCIN/AEI/10.13039/501100011033Junta de
AndalucÃa and European Funds, project no. P18-FR-4619Funding for open access charge provided by
Universidad de Granad
A comparative analysis of configurations of linear Fresnel collectors for concentrating solar power
Linear Fresnel collector arrays present some relevant advantages in the domain of concentrating solar power because of their simplicity, robustness and low capital cost. However, they also present important drawbacks and limitations, notably their average concentration ratio, which seems to limit significantly the performance of these systems.
First, the paper addresses the problem of characterizing the mirror field configuration assuming hourly data of a typical year, in reference to a configuration similar to that of Fresdemo. For a proper comparative study, it is necessary to define a comparison criterion. In that sense, a new variable is defined, the useful energy efficiency, which only accounts for the radiation that impinges on the receiver with intensities above a reference value. As a second step, a comparative study between central linear Fresnel reflectors and compact linear Fresnel reflectors is carried out. This analysis shows that compact linear Fresnel reflectors minimize blocking and shading losses compared to a central configuration. However this minimization is not enough to overcome other negative effects of the compact Fresnel collectors, as the greater dispersion of the rays reaching the receiver, caused by the fact that mirrors must be located farther from the receiver, which yields to lower efficiencies
The functional properties of a truncated form of endothelial cell protein C receptor generated by alternative splicing
BACKGROUND: A soluble form of endothelial cell protein C receptor (sEPCR) is generated by shedding of the cellular form. sEPCR binds to protein C and factor VIIa and inhibits both the activation of protein C and the activity of activated protein C and factor VIIa. High sEPCR levels may increase the risk of thrombosis. We wanted to explore the possibility of detecting soluble endothelial cell protein C receptor forms generated by alternative splicing.
DESIGN AND METHODS: Reverse transcriptase polymerase chain reaction was used to look for new forms of endothelial cell protein C receptor. A yeast expression system was used to generate sufficient amounts of the distinct sEPCR forms. Surface plasmon resonance experiments, chromogenic assays, clotting assays and immunoassays were subsequently performed to characterize a new form of sEPCR that was found.
RESULTS: We demonstrated, by reverse transcriptase polymerase chain reaction and sequencing, the existence of a new, soluble form of endothelial cell protein C receptor generated by alternative splicing, in which the transmembrane region is replaced by a 56-residue tail (tEPCR). Its cDNA was present in human umbilical vein endothelial cells and in most tissues as well as in lung cancer cells. tEPCR was not located in the membrane of transfected cells. We demonstrated that tEPCR binds to protein C and factor VIIa. tEPCR blocked the generation of activated protein C and inhibited the activity of both activated protein C and factor VIIa. tEPCR was detected, by immunoassays, in the supernatant of lung cancer cells and human umbilical vein endothelial cells.
CONCLUSIONS: A truncated form of alternatively spliced endothelial cell protein C receptor was detected in the endothelium and cancer cells. tEPCR behaves as sEPCR generated by shedding of the cellular endothelial cell protein C receptor
Analyzing the social factors that influence willingness to pay for the management of invasive alien species under two different strategies: eradication and prevention
This an accepted author's manuscript (AAM) version of an article published in Environmental Management, 48 (2011): 418-43
Rb+ occlusion stabilized by vanadate in gastric H+/K+-ATPase at 25°C
AbstractDespite its similarity with the Na+/K+-ATPase, it has not been possible so far to isolate a K+-occluded state in the H+/K+-ATPase at room temperature. We report here results on the time course of formation of a state containing occluded Rb+ (as surrogate for K+) in H+/K+-ATPase from gastric vesicles at 25°C. Alamethicin (a pore-forming peptide) showed to be a suitable agent to open vesicles, allowing a more efficient removal of Rb+ ions from the intravesicular medium than C12E8 (a non-ionic detergent). In the presence of vanadate and Mg2+, the time course of [86Rb]Rb+ uptake displayed a fast phase due to Rb+ occlusion. The specific inhibitor of the H+/K+-ATPase SCH28080 significantly reduces the amount of Rb+ occluded in the vanadate–H+/K+-ATPase complex. Occluded Rb+ varies with [Rb+] according to a hyperbolic function with K0.5=0.29±0.06mM. The complex between the Rb+-occluded state and vanadate proved to be very stable even after removal of free Mg2+ with EDTA. Our results yield a stoichiometry lower than one occluded Rb+ per phosphorylation site, which might be explained assuming that, unlike for the Na+/K+-ATPase, Mg2+-vanadate is unable to recruit all the Rb+-bound to the Rb+-occluded form of the Rb+–vanadate–H+/K+-ATPase complex
Development of genomic simple sequence repeat markers for yam
Yam (
Dioscorea
spp.) is a major staple crop
widely cultivated for its starchy tubers. To date,
very few marker resources are publicly avail
-
able as tools for genetic and genomic studies of
this economically important crop. In this study,
90 simple sequence repeat (SSR) markers were
developed from an enriched genomic library of
yellow Guinea yam (
D. cayenensis
Lam.). Cross-
amplification revealed that 85 (94.4%) and 51
(56.7%) of these SSRs could be successfully
transferred to the two major cultivated species
of
D. rotundata
Poir. and
D. alata
L., respec
-
tively. Polymorphisms in 30 markers selected
on the basis of reliability and reproducibility of
DNA bands were evaluated using a panel of 12
D. cayenensis
, 48
D. rotundata
, and 48
D. alata
accessions. Accordingly, number of alleles
per locus ranged from 2 to 8 in
D. cayenensis
(mean = 3.9), 3 to 30 in
D. rotundata
(mean =
13.9), and 2 to 22 in
D. alata
(mean = 12.1). The
average observed and expected heterozygosi
-
ties were 0.156 and 0.634 (
D. cayenensis
), 0.326
and 0.853 (
D. rotundata
), and 0.247 and 0.836
(
D. alata
), respectively. Clustering based on six
SSRs that were polymorphic in at least four of
the five cultivated
Dioscorea
species studied,
including
D. cayenensis
,
D. rotundata
,
D. alata
,
D. dumetorum
(Kunth) Pax., and
D. bulbifera
L.,
detected groups consistent with the phyloge
-
netic relationships of the species except for
D.
dumetorum
. These new SSR markers are invalu
-
able resources for applications such as genetic
diversity analysis and marker-assisted breedingYam (
Dioscorea
spp.) is a major staple crop
widely cultivated for its starchy tubers. To date,
very few marker resources are publicly avail
-
able as tools for genetic and genomic studies of
this economically important crop. In this study,
90 simple sequence repeat (SSR) markers were
developed from an enriched genomic library of
yellow Guinea yam (
D. cayenensis
Lam.). Cross-
amplification revealed that 85 (94.4%) and 51
(56.7%) of these SSRs could be successfully
transferred to the two major cultivated species
of
D. rotundata
Poir. and
D. alata
L., respec
-
tively. Polymorphisms in 30 markers selected
on the basis of reliability and reproducibility of
DNA bands were evaluated using a panel of 12
D. cayenensis
, 48
D. rotundata
, and 48
D. alata
accessions. Accordingly, number of alleles
per locus ranged from 2 to 8 in
D. cayenensis
(mean = 3.9), 3 to 30 in
D. rotundata
(mean =
13.9), and 2 to 22 in
D. alata
(mean = 12.1). The
average observed and expected heterozygosi
-
ties were 0.156 and 0.634 (
D. cayenensis
), 0.326
and 0.853 (
D. rotundata
), and 0.247 and 0.836
(
D. alata
), respectively. Clustering based on six
SSRs that were polymorphic in at least four of
the five cultivated
Dioscorea
species studied,
including
D. cayenensis
,
D. rotundata
,
D. alata
,
D. dumetorum
(Kunth) Pax., and
D. bulbifera
L.,
detected groups consistent with the phyloge
-
netic relationships of the species except for
D.
dumetorum
. These new SSR markers are invalu
-
able resources for applications such as genetic
diversity analysis and marker-assisted breedin
Association of aromatase and estrogen receptor gene polymorphisms with hip fractures
Producción CientÃficaSummary Two polymorphisms of the aromatase and estrogen
receptor genes appeared to interact to influence the risk of
hip fractures in women.
Introduction Allelic variants of the aromatase gene have
been associated with bone mineral density and vertebral
fractures. Our objective was to analyze the relationship
between two polymorphisms of the aromatase and estrogen
receptor genes and hip fracture
- …