266 research outputs found
1897 Ruby Yearbook
A digitized copy of the 1897 Ruby, the Ursinus College yearbook.https://digitalcommons.ursinus.edu/ruby/1003/thumbnail.jp
Public policies to support agroecology in Latin America and the Caribbean
Latin American agroecology proposes a transformation of conventional agri-food systems. It is driven by social movements that have succeeded in forming coalitions that have promoted its integration into public policies. These policies involve a range of instruments that are often embedded in programmes that also support organic agriculture and sustainable agriculture. However, while these two types of agriculture propose more ecological practices, they do not question the basis of the conventional agri-food system. The implementation of instruments to support agroecology therefore depends on the power relations established within each country. This Perspective analyses these policies and their influence on the development of agroecology in eight countries: Argentina, Brazil, Chile, Costa Rica, Cuba, El Salvador, Mexico, and Nicaragua. These policies remain fragile, while support for large-scale conventional agriculture is still predominant. Their challenge is therefore to convince more broadly farmers, consumers and policymakers about the importance of issues such as public health and food security
Effects of infection history on dengue virus infection and pathogenicity
The understanding of immunological interactions among the four dengue virus (DENV)
serotypes and their epidemiological implications is often hampered by the lack of individuallevel infection history. Using a statistical framework that infers full infection history, we
analyze a prospective pediatric cohort in Nicaragua to characterize how infection history
modulates the risks of DENV infection and subsequent clinical disease. After controlling for
age, one prior infection is associated with 54% lower, while two or more are associated with
91% higher, risk of a new infection, compared to DENV-naive children. Children >8 years old
have 55% and 120% higher risks of infection and subsequent disease, respectively, than their
younger peers. Among children with â„1 prior infection, intermediate antibody titers increase,
whereas high titers lower, the risk of subsequent infection, compared with undetectable
titers. Such complex dependency needs to be considered in the design of dengue vaccines
and vaccination strategies
Three applications of path integrals: equilibrium and kinetic isotope effects, and the temperature dependence of the rate constant of the [1,5] sigmatropic hydrogen shift in (Z)-1,3-pentadiene
Recent experiments have confirmed the importance of nuclear quantum effects
even in large biomolecules at physiological temperature. Here we describe how
the path integral formalism can be used to describe rigorously the nuclear
quantum effects on equilibrium and kinetic properties of molecules.
Specifically, we explain how path integrals can be employed to evaluate the
equilibrium (EIE) and kinetic (KIE) isotope effects, and the temperature
dependence of the rate constant. The methodology is applied to the [1,5]
sigmatropic hydrogen shift in pentadiene. Both the KIE and the temperature
dependence of the rate constant confirm the importance of tunneling and other
nuclear quantum effects as well as of the anharmonicity of the potential energy
surface. Moreover, previous results on the KIE were improved by using a
combination of a high level electronic structure calculation within the
harmonic approximation with a path integral anharmonicity correction using a
lower level method.Comment: 9 pages, 4 figure
Fostering future global nurse leaders to work toward meeting Millennium Development Goals (MDGs) and Sustainable Development Goals (SDGs): a global health intern program at Johns Hopkins University School of Nursing
From buzzword to lasting change: The journey from headcount diversity to truly inclusive nursing communities
Analysis of the Interactions Taking Place in the Recognition Site of a Bimetallic Mg(II)âZn(II) Enzyme, Isopentenyl Diphosphate Isomerase. A Parallel Quantum-Chemical and Polarizable Molecular Mechanics Study
Design of Group IIA Secreted/Synovial Phospholipase A2 Inhibitors: An Oxadiazolone Derivative Suppresses Chondrocyte Prostaglandin E2 Secretion
Group IIA secreted/synovial phospholipase A2 (GIIAPLA2) is an enzyme involved in the synthesis of eicosanoids such as prostaglandin E2 (PGE2), the main eicosanoid contributing to pain and inflammation in rheumatic diseases. We designed, by molecular modeling, 7 novel analogs of 3-{4-[5(indol-1-yl)pentoxy]benzyl}-4H-1,2,4-oxadiazol-5-one, denoted C1, an inhibitor of the GIIAPLA2 enzyme. We report the results of molecular dynamics studies of the complexes between these derivatives and GIIAPLA2, along with their chemical synthesis and results from PLA2 inhibition tests. Modeling predicted some derivatives to display greater GIIAPLA2 affinities than did C1, and such predictions were confirmed by in vitro PLA2 enzymatic tests. Compound C8, endowed with the most favorable energy balance, was shown experimentally to be the strongest GIIAPLA2 inhibitor. Moreover, it displayed an anti-inflammatory activity on rabbit articular chondrocytes, as shown by its capacity to inhibit IL-1ÎČ-stimulated PGE2 secretion in these cells. Interestingly, it did not modify the COX-1 to COX-2 ratio. C8 is therefore a potential candidate for anti-inflammatory therapy in joints
Beyond Teaching and Learning: Bringing Together Science and Society with and through Movies
The dissociation catastrophe in fluctuating-charge models and its implications for the concept of atomic electronegativity
We have recently developed the QTPIE (charge transfer with polarization
current equilibration) fluctuating-charge model, a new model with correct
dissociation behavior for nonequilibrium geometries. The correct asymptotics
originally came at the price of representing the solution in terms of
charge-transfer variables instead of atomic charges. However, we have found an
exact reformulation of fluctuating-charge models in terms of atomic charges
again, which is made possible by the symmetries of classical electrostatics. We
show how this leads to the distinguishing between two types of atomic
electronegativities in our model. While one is a intrinsic property of
individual atoms, the other takes into account the local electrical
surroundings. This suggests that this distinction could resolve some confusion
surrounding the concept of electronegativity as to whether it is an intrinsic
property of elements, or otherwise.Comment: 17 pages, prepared for "Proceedings of QSCP-XIII" in Prog. Theor.
Chem. Phy
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