953 research outputs found
Projeto Yabas: Reflections on Hip Hop and Black Women’s Self-making in Recife, Brazil
In
this
article,
we
present
and
reflect
upon
Projeto
Yabas,
a
collaborative
community-based
project
that,
through
hip
hop,
seeks
to
facilitate
young
women’s
conceptualization
of
themselves
as
Black
women
and
to
recognize
and
combat
racial
and
sexual
domestic
violence
in
Recife,
Brazil.
We
explore
how
Black
feminist
theory
can
be
used
by
Black
women
activists
in
the
hip
hop
movement
in
Recife
to
engage
in
empowering
forms
of
self-making
that
are
crucial
for
their
development
as
active
political
subjects.
Reflecting
on
the
experiences
of
Projeto
Yabas
highlights
the
need
to
critically
examine
certain
aspects
of
the
hip
hop
movement’s
political
activism
and
organization,
namely,
the
participation
of
women
within
the
movement
and
the
possibilities
of
Black
feminist
thought
Monensin Improves the Effectiveness of meso-Dimercaptosuccinate when Used to Treat Lead Intoxication in Rats
Among divalent cations, the ionophore monensin shows high activity and selectivity for the transport of lead ions (Pb(2+)) across phospholipid membranes. When coadministered to rats that were receiving meso-dimercaptosuccinate for treatment of Pb intoxication, monensin significantly increased the amount of Pb removed from femur, brain, and heart. It showed a tendency to increase Pb removal from liver and kidney but had no effect of this type in skeletal muscle. Tissue levels of several physiologic (calcium, cobalt, copper, iron, magnesium, manganese, molybdenum, zinc) and nonphysiologic (arsenic, cadmium, chromium, nickel, strontium) elements were also determined after the application of these compounds. Among the physiologic elements, a number of significant changes were seen, including both rising and falling values. The size of these changes was typically around 20% compared with control values, with the largest examples seen in femur. These changes often tended to reverse those of similar size that had occurred during Pb administration. Among the nonphysiologic elements, which were present in trace amounts, the changes were smaller in number but larger in size. None of these changes appears likely to be significant in terms of toxicity, and there were no signs of overt toxicity under any of the conditions employed. Monensin may act by cotransporting Pb(2+) and OH(–) ions out of cells, in exchange for external sodium ions. The net effect would be to shuttle intracellular Pb(2+) to extracellular dimercaptosuccinic acid thereby enhancing its effectiveness. Thus, monensin may be useful for the treatment of Pb intoxication when applied in combination with hydrophilic Pb(2+) chelators
State of Knowledge in Tiller Dynamics
Persistence of sown pastures is a concern for pastoral production worldwide. Fundamentally, when a pasture does not persist the problem can be expressed in terms of inadequate new tiller production or excessive tiller death. However, the collection of data to build an understanding of sward dynamics at this level is time consuming. Tiller survival diagrams are presented for a range of temperate and tropical grass species including Lolium perenne, Lolium multiflorum, Festuca arundinacea, Festuca pratensis, Phleum pratense, Bromus willdenowii, Cynodon dactylon, Brachiaria brizantha, Panicum maximum, Chloris gayana and Paspalum notatum. It is shown that each grass has a unique perennation strategy and accordingly unique strengths and weaknesses that confer persistence or lack of persistence in different situations. There is also confusion in extension circles about the trade-off between tiller size and tiller density and how to detect a suboptimal tiller density. Grass swards respond to high herbage mass by increase of tiller size and reduction in tiller density, but reduction in tiller density is often mistaken for sward decline. A distinctionmust be made between size/density compensation and sward decline. Increased understanding of sward dynamics at this level should help in the evolution of management practices that improve persistence on a range of grassland types
State of knowledge in tiller dynamics
Persistence of sown pastures is a concern for pastoral production worldwide. Fundamentally, when a pasture does not persist the problem can be expressed in terms of inadequate new tiller production or excessive tiller death. However, the collection of data to build an understanding of sward dynamics at this level is time consuming. Tiller survival diagrams are presented for a range of temperate and tropical grass species including Lolium perenne, Lolium multiflorum, Festuca arundinacea, Festuca pratensis, Phleum pratense, Bromus willdenowii, Cynodon dactylon, Brachiaria brizantha, Panicum maximum, Chloris gayana and Paspalum notatum. It is shown that each grass has a unique perennation strategy and accordingly unique strengths and weaknesses that confer persistence or lack of persistence in different situations. There is also confusion in extension circles about the trade-off between tiller size and tiller density and how to detect a suboptimal tiller density. Grass swards respond to high herbage mass by increase of tiller size and reduction in tiller density, but reduction in tiller density is often mistaken for sward decline. A distinctionmust be made between size/density compensation and sward decline. Increased understanding of sward dynamics at this level should help in the evolution of management practices that improve persistence on a range of grassland types.La persistencia de los pastos sembrados es una preocupación para la producción pastoril a nivel mundial. Fundamentalmente, cuando una pastura no persiste, el problema puede expresarse en términos de producción inadecuada de nuevos macollos o muerte excesiva de macollos. Sin embargo, la recopilación de datos para comprender la dinámica de los céspedes a este nivel requiere mucho tiempo. Se presentan diagramas de supervivencia de macollos para una variedad de especies de pastos templados y tropicales que incluyen Lolium perenne, Lolium multiflorum, Festuca arundinacea, Festuca pratensis, Phleum pratense, Bromus willdenowii, Cynodon dactylon, Brachiaria brizantha, Panicum maximum, Chloris gayana y Paspalum notatum. Se muestra que cada pasto tiene una estrategia de perennación única y, en consecuencia, fortalezas y debilidades únicas que le confieren persistencia o falta de persistencia en diferentes situaciones. También existe confusión en los círculos de extensión acerca de la compensación entre el tamaño de los retoños y la densidad de los retoños y cómo detectar una densidad de retoños subóptima. Las praderas de hierba responden a una gran masa de forraje mediante el aumento del tamaño de los macollos y la reducción de la densidad de los macollos, pero la reducción de la densidad de los macollos a menudo se confunde con la disminución del césped. Se debe hacer una distinción entre la compensación de tamaño/densidad y la disminución del césped. Una mayor comprensión de la dinámica de los pastos a este nivel debería ayudar en la evolución de las prácticas de gestión que mejoran la persistencia en una variedad de tipos de pastizales.Estación Experimental Agropecuaria PergaminoFil: Matthew, Cory. Massey University. Institute of Agriculture and Environment; Nueva ZelandiaFil: Agnusdei, Monica Graciela. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Assuero, Silvia G. Universidad Nacional de Mar del Plata; ArgentinaFil: Sbrissia, André F. Santa Catarina State University; BrasilFil: Scheneiter, Jorge Omar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Pergamino; ArgentinaFil: Silva, Sila C. da. Universidade de Sao Paulo; Brasi
Implementation of a Toffoli Gate with Superconducting Circuits
The quantum Toffoli gate allows universal reversible classical computation.
It is also an important primitive in many quantum circuits and quantum error
correction schemes. Here we demonstrate the realization of a Toffoli gate with
three superconducting transmon qubits coupled to a microwave resonator. By
exploiting the third energy level of the transmon qubit, the number of
elementary gates needed for the implementation of the Toffoli gate, as well as
the total gate time can be reduced significantly in comparison to theoretical
proposals using two-level systems only. We characterize the performance of the
gate by full process tomography and Monte Carlo process certification. The gate
fidelity is found to be %.Comment: 4 pages, 5figure
Carboxymethylchitosan/poly (amidoamine) dendrimer nanoparticles in central nervous systems-regenerative medicine: effects on neuron/glial cell viability and internalization efficiency
The applicability of CMCht/PAMAM dendrimer nanoparticles for CNS applications was
investigated. AFM and TEM observations revealed that the nanoparticles possessed a nanosphere-
like shape with a size from 22.0 to 30.7 nm. The nanoparticles could be bound to
fluorescent-probe FITC for tracing purposes. Post-natal hippocampal neurons and cortical glial
cells were both able to internalize the FITC-labeled
CMCht/PAMAM dendrimer nanoparticles with
high efficiency. The percentage of positive cells
internalizing the nanoparticles varied, reaching a
peak after 48 h of incubation. Further experiments
for periods up to 7 d revealed that the
periodical addition of FITC-labelled CMCht/
PAMAM dendrimer nanoparticles was needed to
maintain the overall percentage of cells internalizing
them. Finally, it was also observed that cell
viability was not significantly affected by the
incubation of dendrimer nanoparticles.Financial support from the Portuguese Foundation for Science and Technology through funds from POCTI and/or FEDER programs (Funding to ICVS, 3B's Research Group, post-doctoral and pre-doctoral fellowships to A.J. Salgado and J.M. Oliveira - SFRH/BPD/17595/2004; SFRH/BD/21786/2005) is gratefully acknowledged. This work was also carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283) and HIPPOCRATES STREP (NMP3-CT-2003-505758) projects
Overexpression of Mcl-1 exacerbates lymphocyte accumulation and autoimmune kidney disease in lpr mice
Cell death by apoptosis has a critical role during embryonic development and in maintaining tissue homeostasis. In mammals,
there are two converging apoptosis pathways: the ‘extrinsic’ pathway, which is triggered by engagement of cell surface ‘death
receptors’ such as Fas/APO-1; and the ‘intrinsic’ pathway, which is triggered by diverse cellular stresses, and is regulated by prosurvival
and pro-apoptotic members of the Bcl-2 family of proteins. Pro-survival Mcl-1, which can block activation of the proapoptotic
proteins, Bax and Bak, appears critical for the survival and maintenance of multiple haemopoietic cell types. To
investigate the impact on haemopoiesis of simultaneously inhibiting both apoptosis pathways, we introduced the vavP-Mcl-1
transgene, which causes overexpression of Mcl-1 protein in all haemopoietic lineages, into Faslpr/lpr mice, which lack functional
Fas and are prone to autoimmunity. The combined mutations had a modest impact on myelopoiesis, primarily an increase in the
macrophage/monocyte population in Mcl-1tg/lpr mice compared with lpr or Mcl-1tg mice. The impact on lymphopoiesis was
striking, with a marked elevation in all major lymphoid subsets, including the non-conventional double-negative (DN) T cells
(TCRβ+
CD4–
CD8–
B220+
) characteristic of Faslpr/lpr mice. Of note, the onset of autoimmunity was markedly accelerated in Mcl-1tg/lpr
mice compared with lpr mice, and this was preceded by an increase in immunoglobulin (Ig)-producing cells and circulating
autoantibodies. This degree of impact was surprising, given the relatively mild phenotype conferred by the vavP-Mcl-1 transgene
by itself: a two- to threefold elevation of peripheral B and T cells, no significant increase in the non-conventional DN T-cell
population and no autoimmune disease. Comparison of the phenotype with that of other susceptible mice suggests that the
development of autoimmune disease in Mcl-1tg/lpr mice may be influenced not only by Ig-producing cells but also other
haemopoietic cell types
Compensação tamanho/densidade populacional de perfilhos em pastos de Tifton 85
The objective of this study was to evaluate the occurrence of the tiller size/density compensation mechanism in Tifton 85 bermudagrass swards grazed by sheep under continuous stocking. Treatments corresponded to four sward steady state conditions (5, 10, 15, and 20 cm of sward surface height), maintained by sheep grazing. The experimental design was a complete randomized block with four replicates. Pasture responses evaluated include: tiller population density, tiller mass, leaf mass and leaf area per tiller, and herbage mass. Tiller volume, leaf area index, tiller leaf/stem ratio, and tiller leaf area/volume ratio were calculated and simple regression analyses between tiller population density and tiller mass were performed. Measurements were made in December, 1998, and January, April, and July, 1999. The swards showed a tiller size/density compensation mechanism in which high tiller population densities were associated with small tillers and vice-versa, except in July, 1999. Regression analyses revealed that linear coefficients were steeper than the theoretical expectation of -3/2. Increments in herbage mass were attributable to increases in tiller mass in December and January. Leaf area/volume ratio values of Tifton 85 tillers were much lower than those commonly found for temperate grass species.O objetivo deste trabalho foi avaliar a ocorrência do mecanismo de compensação tamanho/densidade populacional de perfilhos em pastagens de Tifton 85 (Cynodon spp.). Os tratamentos corresponderam a quatro condições de pasto (5, 10, 15 e 20 cm de altura), mantidas constantes por ovinos em regime de lotação contínua e taxa de lotação variável. O delineamento experimental foi o de blocos completos casualizados com quatro repetições. As variáveis densidade populacional de perfilhos, massa por perfilho, massa de folha por perfilho, área foliar por perfilho, massa de forragem, volume por perfilho, índice de área foliar, relação folha/haste e razão entre área foliar/volume do perfilho (R) foram avaliadas. Além disso, regressões simples foram realizadas entre densidade populacional de perfilhos e massa por perfilho. As medições foram realizadas em dezembro de 1998 e janeiro, abril e julho de 1999. Os resultados mostraram que pastagens de Cynodon spp. apresentaram um mecanismo de compensação tamanho/densidade populacional de perfilhos, em que maiores densidades populacionais estiveram associadas a perfilhos pequenos e vice-versa, exceto em julho de 1999. Análises de regressão mostraram coeficientes lineares menores que a expectativa teórica de -3/2. Aumentos em massa de forragem em dezembro e janeiro resultaram de aumentos em massa por perfilho. Os valores de R foram menores que aqueles encontrados para plantas de clima temperado, indicando um maior nível de integração clonal entre plantas de Tifton 85
Hemoglobin, Lead Exposure, and Intelligence Quotient: Effect Modification by the DRD2 Taq IA Polymorphism
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