8,726 research outputs found
Risk for Preeclampsia Associated with Nutritional Deficiencies and Modified by APOL1 Genotype
Preeclampsia (PE) is a hypertensive disorder of pregnancy that is associated with micronutrient deficiencies. Nutrients involved in placental health and maintenance, such as vitamin D and folate, are important nutrients to assess in the risk of PE. As gestational age increases, the levels of vitamin D and folate potentially have incrementally increasing concentrations associated with PE. In addition to micronutrient deficiencies, PE is also associated with the presence of APOL1 high-risk (HR) variants. It was also hypothesized that a potential additive effect exists between HR APOL1 genotype status and nutritional deficiencies that would place individuals at a higher risk of developing PE. A systematic and meta-analysis was conducted to assess the hypothesis that vitamin D and folate levels were risk factors for PE based on specific gestational time periods. Additionally, a case-control study was conducted using a subset of African American mother and infant dyads collected from the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) cohort in Memphis, TN. This study included maternal blood samples that assessed serum vitamin D and folate levels during the 2nd and 3rd trimesters of pregnancy. Logistic regression model was used to further assess whether maternal or fetal apolipoprotein genotype status modified the association with PE and folate or vitamin D. In addition to maternal blood samples, reported micronutrient intake of calcium, magnesium, selenium and folate were also assessed. Low vitamin D and folate levels were associated with the development of PE in the systematic review and meta-analyses. Case-control studies further evaluated this association and expanded current understanding by assessing vitamin D and folate deficiencies in conjunction with APOL1 genotype status. When having a child with HR APOL1 genotype, African American women with 25(OH)D lower than 20 ng/mL in the 2nd or 3rd trimester were found to have a two-fold and six-fold increased odds of developing PE. We found a similar association with the assessment of folate levels. Individuals with plasma folate less than 15 ng/mL within the 2nd trimester and a child with fetal APOL1 HR genotype were at a three-fold risk of developing PE. Findings suggest the importance of nutrigenetics in future PE research
Accelerated Broadband Spectra and Attosecond Charge Migration Simulations using Real-Time Time-Dependent Density Functional Theory
In this dissertation, the calculations of light-matter interactions offer insight into the structure and dynamical response of electrons in molecular systems. Such information is useful for characterizing molecules, electronic structure, photochemistry, photomaterials, and a host of other applications. In the first part of this work, simulations of broadband absorption spectra are accelerated by the use of Pad´e approximanants of Fourier Transforms and dipole decomposition. Electronic absorption spectra from valence and core levels are obtained using time-dependent methods and compared to results from established perturbative techniques. In addition, core level absorption spectra are calculated for a nickel porphyrin and shown to be consistent with experimental XANES spectra. Not only is the speed up of these real-time simulations significant (at least 5x faster), but such methods offer the ability to directly calculate the dipole response from molecular orbital pairs involved in a given transition. In the second part of this dissertation, time-dependent density functional theory (TDDFT) calculations were performed to capture core-hole-initiated charge migration. By using welldefined initial states, well-known problems of resonant excitation (with TDDFT) caused by the adiabatic approximation are avoided. Using such initial states, core-hole-initiated valence charge migration is obtained in nitrosobenzene by TDDFT. These results are shown to be in good agreement with those of more accurate methods, provided the use of a hybrid functional to incorporate both electron correlation and exchange. In addition, the timedependent electron localization function (TD-ELF) can convert the density into a Lewis-dot picture of bonds and lone pairs of electrons. Building upon these charge migration studies, initial states in the valence orbitals were also constructed. In valence ionization, the electron is partially removed from multiple channels or orbitals; thus, multiple orbitals are involved in constructing the valence hole initial states. Due to the sudden ionization approximation made by construction of the vi initial states, a broadband-like response causes many dynamical modes to be excited. Here, the amplitude and phase of Fourier transforms are used to extract and classify the modes as charge migration or density-like excitation. These modes are then used to calculate metrics like migration distance and speed. Using this information in conjuction with the TD-ELF, it becomes possible to not only interpret charge migration, but to predict it by established chemical principles
Desarrollo, cultura y educación: algunas reflexiones sobre lo que debería estudiar la psicología
Se recogen las reflexiones presentadas en el VII Congreso Internacional de Psicología y Educación y XXI Congreso de INFAD. La ciencia de la psicología trata de investigar y comprender la condición humana. Considera que los métodos convencionales de investigación psicológica no tienen en cuenta factores como la incidencia de la educación y la cultura, que el psicólogo puede aprender del antropólogo, del sociólogo y del historiador. Nunca se comprenderá el comportamiento humano estudiándolo fuera de contexto. Se necesita ir más allá de los estudios convencionales sobre pensamiento lógico y asociativo y adentrarse en el ámbito del pensamiento narrativo. Esta investigación cultural es esencial para cultivar y mantener la profundidad y la extensión de la psicología. La educación no es lo único, ni debe dedicarse exclusivamente, a la transmisión del conocimiento establecido. También debe cultiva la conciencia de la condición humana. La educación no es solo llegar a dominar un contenido, también es lograr captar en qué consiste conocer y comprender.This article collects his reflections presented at the VII International Congress of Psychology and Education and XXI Congress of INFAD. The science of psychology tries to investigate and understand the human condition. Considers that the conventional methods of psychological investigation do not take into account factors such as the incidence of education and culture, that the psychologist can learn of the anthropologist, sociologist and historian. Never can be understood the human behavior studying it out of context. We need to go beyond the conventional studies on logical thinking and associative and we need to go into the field of thought narrative. This cultural research is essential to cultivate and maintain the depth and extent of psychology. Education is not the only thing, nor should be devoted exclusively to the transmission of knowledge established. You must also cultivate the conscience of the human condition. Education is not the only content, it's also capture what is know and understand.peerReviewe
Automated verification of shape, size and bag properties.
In recent years, separation logic has emerged as a contender for formal reasoning of heap-manipulating imperative programs. Recent works have focused on specialised provers that are mostly based on fixed sets of predicates. To improve expressivity, we have proposed a prover that can automatically handle user-defined predicates. These shape predicates allow programmers to describe a wide range of data structures with their associated size properties. In the current work, we shall enhance this prover by providing support for a new type of constraints, namely bag (multi-set) constraints. With this extension, we can capture the reachable nodes (or values) inside a heap predicate as a bag constraint. Consequently, we are able to prove properties about the actual values stored inside a data structure
Compatriot and foreigner : a study of impression formation in three countries
Caption title"February 5, 1957."At head of title: Communications Program. Experimental Section"350"--handwritten on coverIncludes bibliographical references (leaf 21
Attosecond time-resolved photoelectron holography
Ultrafast strong-field physics provides insight into quantum phenomena that evolve on an attosecond time scale, the most fundamental of which is quantum tunneling. The tunneling process initiates a range of strong field phenomena such as high harmonic generation (HHG), laser-induced electron diffraction, double ionization and photoelectron holography—all evolving during a fraction of the optical cycle. Here we apply attosecond photoelectron holography as a method to resolve the temporal properties of the tunneling process. Adding a weak second harmonic (SH) field to a strong fundamental laser field enables us to reconstruct the ionization times of photoelectrons that play a role in the formation of a photoelectron hologram with attosecond precision. We decouple the contributions of the two arms of the hologram and resolve the subtle differences in their ionization times, separated by only a few tens of attoseconds
5.5-7.5 MeV Proton generation by a moderate intensity ultra-short laser interaction with H2O nano-wire targets
We report on the first generation of 5.5-7.5 MeV protons by a moderate
intensity short-pulse laser (4.5 \times 1017 W/cm^2, 50 fsec) interacting with
H2O nano-wires (snow) deposited on a Sapphire substrate. In this setup, the
laser intensity is locally enhanced by the tip of the snow nano-wire, leading
to high spatial gradients. Accordingly, the plasma near the tip is subject to
enhanced ponderomotive potential, and confined charge separation is obtained.
Electrostatic fields of extremely high intensities are produced over the short
scale length, and protons are accelerated to MeV-level energies.Comment: submitted to PRL, under press embargo. 6 figure
Designing Performer Training: Digital Encounters with Things and People
This article investigates how digital technologies can be used to enhance the relational aspects of performer training. Saner and Robinson reflect on a practice as research project, Enactive Encounters, where they use poor technology and everyday objects to create participatory learning environments. The teacher- student relationship is challenged and transformed into playful interactions between participants through enactive encounters that aim to embody different aspects of specific training practices.
Keywords: digital training, relational pedagogy, enactivism
Soft X-ray emission lines of Fe XV in solar flare observations and the Chandra spectrum of Capella
Recent calculations of atomic data for Fe XV have been used to generate
theoretical line ratios involving n = 3-4 transitions in the soft X-ray
spectral region (52-83 A), for a wide range of electron temperatures and
densities applicable to solar and stellar coronal plasmas. A comparison of
these with solar flare observations from a rocket-borne spectrograph (XSST)
reveals generally good agreement between theory and experiment. In particular,
the 82.76 A emission line in the XSST spectrum is identified, for the first
time to our knowledge in an astrophysical source. Most of the Fe XV transitions
which are blended have had the species responsible clearly identified, although
there remain a few instances where this has not been possible. The line ratio
calculations are also compared with a co-added spectrum of Capella obtained
with the Chandra satellite, which is probably the highest signal-to-noise
observation achieved for a stellar source in the 25-175 A soft X-ray region.
Good agreement is found between theory and experiment, indicating that the Fe
XV lines are reliably detected in Chandra spectra, and hence may be employed as
diagnostics to determine the temperature and/or density of the emitting plasma.
However the line blending in the Chandra data is such that individual emission
lines are difficult to measure accurately, and fluxes may only be reliably
determined via detailed profile fitting of the observations. The co-added
Capella spectrum is made available to hopefully encourage further exploration
of the soft X-ray region in astronomical sources.Comment: 27 pages, 10 figures, Astrophysical Journal, in pres
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