184 research outputs found
Slavery and abortion: the paradox of american liberalism
Louis Hartz proposed that America possesses a liberal tradition that works toward a Lockean equality for all people. I argue that Hartzs\u27 theory is still applicable to America even though illiberal institutions have and do exist. My contention is that it is the paradox of liberalism that allows for this. Slavery is the quintessential illiberal institution, yet liberal concepts allowed it to exist in America for over 200 years. It is my contention that abortion is another illiberal institution that is being promoted by the paradox of liberalism. With the use of John Rawls theory of distributive justice abortion can be eradicated from American society while upholding the American liberal tradition
Density Dependence Drives Habitat Production and Survivorship of Acropora cervicornis Used for Restoration on a Caribbean Coral Reef
Coral restoration is gaining traction as a viable strategy to help restore degraded reefs. While the nascent field of coral restoration has rapidly progressed in the past decade, significant knowledge gaps remain regarding the drivers of restoration success that may impede our ability to effectively restore coral reef communities. Here, we conducted a field experiment to investigate the influence of coral density on the growth, habitat production, and survival of corals outplanted for restoration. We used nursery-raised colonies of Acropora cervicornis to experimentally establish populations of corals with either 3, 6, 12, or 24 corals within 4m2 plots, generating a gradient of coral densities ranging from 0.75 corals mā2 to 12 corals mā2. After 13 months we found that density had a significant effect on the growth, habitat production, and survivorship of restored corals. We found that coral survivorship increased as colony density decreased. Importantly, the signal of density dependent effects was context dependent. Our data suggest that positive density dependent effects influenced habitat production at densities of 3 corals mā2, but further increases in density resulted in negative density dependent effects with decreasing growth and survivorship of corals. These findings highlight the importance of density dependence for coral restoration planning and demonstrate the need to evaluate the influence of density for other coral species used for restoration. Further work focused on the mechanisms causing density dependence such as increased herbivory, rapid disease transmission, or altered predation rates are important next steps to advance our ability to effectively restore coral reefs
Is a community still a community? Reviewing definitions of key terms in community ecology
Community ecology is an inherently complicated field, confounded by the conflicting use of fundamental terms. Nearly two decades ago, Fauth etal. (1996) demonstrated that imprecise language led to the virtual synonymy of important terms and so attempted to clearly define four keywords in community ecology; community, assemblage, guild, and ensemble. We revisit Fauth etal.\u27s conclusion and discuss how the use of these terms has changed over time since their review. An updated analysis of term definition from a selection of popular ecological textbooks suggests that definitions have drifted away from those encountered pre-1996, and slightly disagreed with results from a survey of 100 ecology professionals (comprising of academic professors, nonacademic PhDs, graduate and undergraduate biology students). Results suggest that confusion about these terms is still widespread in ecology. We conclude with clear suggestions for definitions of each term to be adopted hereafter to provide greater cohesion among research groups
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. ŠŃŠµŠ“Š¼ŠµŃŠ¾Š¼ ŠøŃŃŠ»ŠµŠ“Š¾Š²Š°Š½ŠøŃ ŠæŃŠµŠ“ŃŃŠ°Š²Š»ŠµŠ½Ń ŃŠ·ŃŠŗŠ¾Š²ŃŠµ ŃŃŠµŠ“ŃŃŠ²Š° ŠŗŠ¾Š½ŃŠµŠæŃŠ° "ŠæŃŠøŃŠ¾Š“Š°" Š² ŃŃŃŃŠŗŠ¾Š¼ Šø Š°Š½Š³Š»ŠøŠ¹ŃŠŗŠ¾Š¼ ŃŠ·ŃŠŗŠ°Ń
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Š¦ŠµŠ»Ń ŃŠ°Š±Š¾ŃŃ ā Š²ŃŃŠ²Š»ŠµŠ½ŠøŠµ ŃŠµŠ¼Š°Š½ŃŠøŃŠµŃŠŗŠøŃ
Š¾ŃŠ¾Š±ŠµŠ½Š½Š¾ŃŃŠµŠ¹ ŃŠµŠ°Š»ŠøŠ·Š°ŃŠøŠø ŠŗŠ¾Š½ŃŠµŠæŃŠ° "ŠæŃŠøŃŠ¾Š“Š°" Š½Š° Š¼Š°ŃŠµŃŠøŠ°Š»Šµ ŃŠ°Š¹ŃŠ¾Š² Š² ŃŃŠµŃŠµ ŠæŃŠøŃŠ¾Š“Š¾ŠæŠ¾Š»ŃŠ·Š¾Š²Š°Š½ŠøŃ Š½Š° ŃŃŃŃŠŗŠ¾Š¼ Šø Š°Š½Š³Š»ŠøŠ¹ŃŠŗŠ¾Š¼ ŃŠ·ŃŠŗŠ°Ń
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Š ŠæŃŠ¾ŃŠµŃŃŠµ ŠøŃŃŠ»ŠµŠ“Š¾Š²Š°Š½ŠøŃ Š±ŃŠ»Šø ŃŠ°ŃŃŠ¼Š¾ŃŃŠµŠ½Ń ŃŠ°ŠŗŠøŠµ ŠæŠ¾Š½ŃŃŠøŃ, ŠŗŠ°Šŗ ŠŗŠ¾Š½ŃŠµŠæŃ, ŃŠ·ŃŠŗŠ¾Š²Š°Ń ŠŗŠ°ŃŃŠøŠ½Š° Š¼ŠøŃŠ°, Š½Š°ŃŃŠ½Š°Ń ŠŗŠ°ŃŃŠøŠ½Š° Š¼ŠøŃŠ°, Š“ŠøŃŠŗŃŃŃ, Š“ŠøŃŠŗŃŃŃŠøŠ²Š½Š°Ń ŠŗŠ°ŃŃŠøŠ½Š° Š¼ŠøŃŠ°, ŠæŃŠ¾Š°Š½Š°Š»ŠøŠ·ŠøŃŠ¾Š²Š°Š½Ń ŃŠµŠ¼Š°Š½ŃŠøŃŠµŃŠŗŠøŠµ Š¾ŃŠ¾Š±ŠµŠ½Š½Š¾ŃŃŠø ŠŗŠ¾Š½ŃŠµŠæŃŠ° "ŠæŃŠøŃŠ¾Š“Š°" Š² ŃŃŃŃŠŗŠ¾Š¼ Šø Š°Š½Š³Š»ŠøŠ¹ŃŠŗŠ¾Š¼ ŃŠ·ŃŠŗŠ°Ń
.The object of the research is the concept ānatureā in virtual discourse in environmental management sphere in Russian and in English. The subject of the research is linguistic means representing the concept ānatureā in Russian and English.
The aim is to identify semantic features of verbalization of the concept ānatureā in texts of virtual environmental management discourse in Russian and in English.
During the research process, the following terms have been considered: concept, linguistic view of the world, scientific view of the world, discourse, discursive view of the world. Semantic features of the linguistic means representing the concept ānatureā in Russian and in English have been analyzed
Direct cooling of the catheter tip increases safety for CMR-guided electrophysiological procedures
<p>Abstract</p> <p>Background</p> <p>One of the safety concerns when performing electrophysiological (EP) procedures under magnetic resonance (MR) guidance is the risk of passive tissue heating due to the EP catheter being exposed to the radiofrequency (RF) field of the RF transmitting body coil. Ablation procedures that use catheters with irrigated tips are well established therapeutic options for the treatment of cardiac arrhythmias and when used in a modified mode might offer an additional system for suppressing passive catheter heating.</p> <p>Methods</p> <p>A two-step approach was chosen. Firstly, tests on passive catheter heating were performed in a 1.5 T Avanto system (Siemens Healthcare Sector, Erlangen, Germany) using a ASTM Phantom in order to determine a possible maximum temperature rise. Secondly, a phantom was designed for simulation of the interface between blood and the vascular wall. The MR-RF induced temperature rise was simulated by catheter tip heating via a standard ablation generator. Power levels from 1 to 6 W were selected. Ablation duration was 120 s with no tip irrigation during the first 60 s and irrigation at rates from 2 ml/min to 35 ml/min for the remaining 60 s (Biotronik Qiona Pump, Berlin, Germany). The temperature was measured with fluoroscopic sensors (Luxtron, Santa Barbara, CA, USA) at a distance of 0 mm, 2 mm, 4 mm, and 6 mm from the catheter tip.</p> <p>Results</p> <p>A maximum temperature rise of 22.4Ā°C at the catheter tip was documented in the MR scanner. This temperature rise is equivalent to the heating effect of an ablator's power output of 6 W at a contact force of the weight of 90 g (0.883 N). The catheter tip irrigation was able to limit the temperature rise to less than 2Ā°C for the majority of examined power levels, and for all examined power levels the residual temperature rise was less than 8Ā°C.</p> <p>Conclusion</p> <p>Up to a maximum of 22.4Ā°C, the temperature rise at the tissue surface can be entirely suppressed by using the catheter's own irrigation system. The irrigated tip system can be used to increase MR safety of EP catheters by suppressing the effects of unwanted passive catheter heating due to RF exposure from the MR scanner.</p
Generation and characterisation of Friedreich ataxia YG8R mouse fibroblast and neural stem cell models
This article has been made available through the Brunel Open Access Publishing Fund.Background: Friedreich ataxia (FRDA) is an autosomal recessive neurodegenerative disease caused by GAA repeat expansion in the first intron of the FXN gene, which encodes frataxin, an essential mitochondrial protein. To further characterise the molecular abnormalities associated with FRDA pathogenesis and to hasten drug screening, the development and use of animal and cellular models is considered essential. Studies of lower organisms have already contributed to understanding FRDA disease pathology, but mammalian cells are more related to FRDA patient cells in physiological terms. Methodology/Principal Findings: We have generated fibroblast cells and neural stem cells (NSCs) from control Y47R mice (9 GAA repeats) and GAA repeat expansion YG8R mice (190+120 GAA repeats). We then differentiated the NSCs in to neurons, oligodendrocytes and astrocytes as confirmed by immunocytochemical analysis of cell specific markers. The three YG8R mouse cell types (fibroblasts, NSCs and differentiated NSCs) exhibit GAA repeat stability, together with reduced expression of frataxin and reduced aconitase activity compared to control Y47R cells. Furthermore, YG8R cells also show increased sensitivity to oxidative stress and downregulation of Pgc-1Ī± and antioxidant gene expression levels, especially Sod2. We also analysed various DNA mismatch repair (MMR) gene expression levels and found that YG8R cells displayed significant reduction in expression of several MMR genes, which may contribute to the GAA repeat stability. Conclusions/Significance: We describe the first fibroblast and NSC models from YG8R FRDA mice and we confirm that the NSCs can be differentiated into neurons and glia. These novel FRDA mouse cell models, which exhibit a FRDA-like cellular and molecular phenotype, will be valuable resources to further study FRDA molecular pathogenesis. They will also provide very useful tools for preclinical testing of frataxin-increasing compounds for FRDA drug therapy, for gene therapy, and as a source of cells for cell therapy testing in FRDA mice. Ā© 2014 Sandi et al
The Role of Hypoxia in 2-ButoxyethanolāInduced Hemangiosarcoma
To understand the molecular mechanisms underlying compound-induced hemangiosarcomas in mice, and therefore, their human relevance, a systems biology approach was undertaken using transcriptomics and Causal Network Modeling from mice treated with 2-butoxyethanol (2-BE). 2-BE is a hemolytic agent that induces hemangiosarcomas in mice. We hypothesized that the hemolysis induced by 2-BE would result in local tissue hypoxia, a well-documented trigger for endothelial cell proliferation leading to hemangiosarcoma. Gene expression data from bone marrow (BM), liver, and spleen of mice exposed to a single dose (4 h) or seven daily doses of 2-BE were used to develop a mechanistic model of hemangiosarcoma. The resulting mechanistic model confirms previous work proposing that 2-BE induces macrophage activation and inflammation in the liver. In addition, the model supports local tissue hypoxia in the liver and spleen, coupled with increased erythropoeitin signaling and erythropoiesis in the spleen and BM, and suppression of mechanisms that contribute to genomic stability, events that could be contributing factors to hemangiosarcoma formation. Finally, an immunohistochemistry method (Hypoxyprobe) demonstrated that tissue hypoxia was present in the spleen and BM. Together, the results of this study identify molecular mechanisms that initiate hemangiosarcoma, a key step in understanding safety concerns that can impact drug decision processes, and identified hypoxia as a possible contributing factor for 2-BEāinduced hemangiosarcoma in mice
Childrenās coping with in vivo peer rejection: An experimental investigation
We examined children's behavioral coping in response to an in vivo peer rejection manipulation. Participants (N=186) ranging between 10 and 13 years of age, played a computer game based on the television show Survivor and were randomized to either peer rejection (i.e., being voted out of the game) or non-rejection control. During a five-min. post-feedback waiting period children's use of several behavioral coping strategies was assessed. Rejection elicited a marked shift toward more negative affect, but higher levels of perceived social competence attenuated the negative mood shift. Children higher in depressive symptoms were more likely to engage in passive and avoidant coping behavior. Types of coping were largely unaffected by gender and perceived social competence. Implications are discussed. Ā© 2006 Springer Science+Business Media, LLC
No Excuses Charter Schools: A Meta-Analysis of the Experimental Evidence on Student Achievement
While charter schools differ widely in philosophy and pedagogical views, the United Statesās most famous urban charter schools typically use the No Excuses approach. Enrolling mainly poor and minority students, these schools feature high academic standards, strict disciplinary codes, extended instructional time, and targeted supports for low-performing students. The strenuous and regimented style is controversial amongst some scholars, but others contend that the No Excuses approach is needed to rapidly close the achievement gap. We conduct the first meta-analysis of the achievement impacts of No Excuses charter schools. Focusing on experimental studies, we find that No Excuses charter schools significantly improve math scores and reading scores. We estimate gains of 0.25 and 0.16 standard deviations on math and literacy achievement, respectively, as the effect of attending a No Excuses charter school for one year. Though the effect is large and meaningful, we offer some caveats to this finding and discuss policy implications for the United States as well as other countries
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