597 research outputs found
The Florida Architecture of F. Burrall Hoffman Jr., 1882-1980
Everyone interested in Florida’s architectural history should know of Francis Burrall Hoffman Jr. and his connection to Miami’s great villa Vizcaya. Few realize he had a distinguished Florida career spanning over sixty years and designed buildings in several sections of the state. In fact, when the United States entered World War I in 1917, the thirty-five-year-old Hoffman may have been, in terms of cost of commissions, Florida’s most successful domestic architect. In only eight short years of private practice, Hoffman had designed Vizcaya, the Biscayne Bay mansion, for industrialist James Deering, large oceanfront residences in Palm Beach for Mrs. Frederick Guest and her brother Henry Carnegie Phipps (their father had been Andrew Carnegie’s partner), and probably had received the commission for the elaborate music room of Pittsburgh industrialist Joseph Riter, which he completed at the war’s end. Moreover, Hoffman returned to Florida to design several houses and Our Lady of Mercy Chapel on Boca Grande; a half century later he began to winter on Jupiter Island where he completed his last major commissions
Magnetic Properties of Undoped
The Heisenberg antiferromagnet, which arises from the large Hubbard
model, is investigated on the molecule and other fullerenes. The
connectivity of leads to an exotic classical ground state with
nontrivial topology. We argue that there is no phase transition in the Hubbard
model as a function of , and thus the large solution is relevant for
the physical case of intermediate coupling. The system undergoes a first order
metamagnetic phase transition. We also consider the S=1/2 case using
perturbation theory. Experimental tests are suggested.Comment: 12 pages, 3 figures (included
Soil organisms in organic and conventional cropping systems.
Apesar do crescente interesse pela agricultura orgânica, são poucas as informações de pesquisa disponÃveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrófico foram comparados os efeitos de sistemas de cultivo orgânico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populações de fungos,bactérias e actinomicetos, determinadas pela contagem de colônias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO2, manteve-se superior no sistema orgânico, sendo que em determinadas avaliações foi o dobro da evolução verificada no sistema convencional. O número de espécimes de minhoca foi praticamente dez vezes maior no sistema orgânico. Não foi observada diferença na taxa de decomposição de matéria orgânica entre os dois sistemas. De modo geral, o número de indivÃduos de microartrópodos foi superior no sistema orgânico do que no sistema convencional, refletindo no maior Ãndice de diversidade de Shannon. As maiores populações de insetos foram as da ordem Collembola, enquanto para os ácaros a maior população foi a da superfamÃlia Oribatuloidea. IndivÃduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas
Erratum: Factors influencing time-location patterns and their impact on estimates of exposure: the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air)
We assessed time-location patterns and the role of individual- and residential-level characteristics on these patterns within the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air) cohort and also investigated the impact of individual-level time-location patterns on individual-level estimates of exposure to outdoor air pollution. Reported time-location patterns varied significantly by demographic factors such as age, gender, race/ethnicity, income, education, and employment status. On average Chinese participants reported spending significantly more time indoors and less time outdoors and in transit than white, black, or Hispanic participants. Using a tiered linear regression approach, we predicted time indoors at home and total time indoors. Our model, developed using forward selection procedures, explained 43 percent of the variability in time spent indoors at home, and incorporated demographic, health, lifestyle, and built environment factors. Time-weighted air pollution predictions calculated using recommended time indoors from USEPA(1) overestimated exposures as compared to predictions made with MESA Air participant-specific information. These data fill an important gap in the literature by describing the impact of individual and residential characteristics on time-location patterns and by demonstrating the impact of population-specific data on exposure estimates
Raman scattering in C_{60} and C_{48}N_{12} aza-fullerene: First-principles study
We carry out large scale {\sl ab initio} calculations of Raman scattering
activities and Raman-active frequencies (RAFs) in
aza-fullerene. The results are compared with those of .
Twenty-nine non-degenerate polarized and 29 doubly-degenerate unpolarized RAFs
are predicted for . The RAF of the strongest Raman
signal in the low- and high-frequency regions and the lowest and highest RAFs
for are almost the same as those of .
The study of reveals the importance of electron correlations and
the choice of basis sets in the {\sl ab initio} calculations. Our best
calculated results for with the B3LYP hybrid density functional
theory are in excellent agreement with experiment and demonstrate the desirable
efficiency and accuracy of this theory for obtaining quantitative information
on the vibrational properties of these molecules.Comment: submitted to Phys.Rev.
Modeling the Residential Infiltration of Outdoor PM2.5 in the Multi-Ethnic Study of Atherosclerosis and Air Pollution (MESA Air)
Background: Epidemiologic studies of fine particulate matter [aerodynamic diameter ≤ 2.5 μm (PM2.5)] typically use outdoor concentrations as exposure surrogates. Failure to account for variation in residential infiltration efficiencies (Finf) will affect epidemiologic study results
Magic Numbers of Silicon Clusters
A structural model for intermediate sized silicon clusters is proposed that
is able to generate unique structures without any dangling bonds. This
structural model consists of bulk-like core of five atoms surrounded by
fullerene-like surface. Reconstruction of the ideal fullerene geometry results
in the formation of crown atoms surrounded by -bonded dimer pairs. This
model yields unique structures for \Si{33}, \Si{39}, and \Si{45} clusters
without any dangling bonds and hence explains why these clusters are least
reactive towards chemisorption of ammonia, methanol, ethylene, and water. This
model is also consistent with the experimental finding that silicon clusters
undergo a transition from prolate to spherical shapes at \Si{27}. Finally,
reagent specific chemisorption reactivities observed experimentally is
explained based on the electronic structures of the reagents.Comment: 4 pages + 3 figures (postscript files after \end{document}
Electron-phonon interaction in C70
The matrix elements of the deformation potential of C are calculated
by means of a simple, yet accurate solution of the electron-phonon coupling
problem in fullerenes, based on a parametrization of the ground state
electronic density of the system in terms of hybridized orbitals.
The value of the calculated dimensionless total electron-phonon coupling
constant is , an order of magnitude smaller than in
C, consistent with the lack of a superconducting phase transition in
CA fullerite, and in overall agreement with measurements of the
broadening of Raman peaks in CK. We also calculate the photoemission
cross section of C, which is found to display less structure than that
associated with C, in overall agreement with the experimental
findings.Comment: To be published in Phys. Rev.
Disparate Functional Responses to β-adrenergic and Ischaemic Challenge in Male and Female Hypertrophic Cardiomyocytes
Cardiac hypertrophy is the most potent cardiovascular risk factor after age, with relative mortality risk greater in women. The cognate issue of whether ischaemia coincident with hypertrophic co-morbidity has differing gender aetiology/outcome has not been addressed. We used a novel polygenic model of hypertrophy to examine male/female cellular stress responses in normal and hypertrophic cardiomyocytes.Centro de Investigaciones Cardiovasculare
Male and female hypertrophic rat cardiac myocyte functional responses to ischemic stress and β-adrenergic challenge are different
Background: Cardiac hypertrophy is the most potent cardiovascular risk factor after age, and relative mortality risk linked with cardiac hypertrophy is greater in women. Ischemic heart disease is the most common form of cardiovascular pathology for both men and women, yet significant differences in incidence and outcomes exist between the sexes. Cardiac hypertrophy and ischemia are frequently occurring dual pathologies. Whether the cellular (cardiomyocyte) mechanisms underlying myocardial damage differ in women and men remains to be determined. In this study, utilizing an in vitro experimental approach, our goal was to examine the proposition that responses of male/female cardiomyocytes to ischemic (and adrenergic) stress may be differentially modulated by the presence of pre-existing cardiac hypertrophy.
Methods: We used a novel normotensive custom-derived hypertrophic heart rat (HHR; vs control strain normal heart rat (NHR)). Cardiomyocyte morphologic and electromechanical functional studies were performed using microfluorimetric techniques involving simulated ischemia/reperfusion protocols.
Results: HHR females exhibited pronounced cardiac/cardiomyocyte enlargement, equivalent to males. Under basal conditions, a lower twitch amplitude in female myocytes was prominent in normal but not in hypertrophic myocytes. The cardiomyocyte Ca2+ responses to β-adrenergic challenge differed in hypertrophic male and female cardiomyocytes, with the accentuated response in males abrogated in females - even while contractile responses were similar. In simulated ischemia, a marked and selective elevation of end-ischemia Ca2+ in normal female myocytes was completely suppressed in hypertrophic female myocytes - even though all groups demonstrated similar shifts in myocyte contractile performance. After 30 min of simulated reperfusion, the Ca2+ desensitization characterizing the male response was distinctively absent in female cardiomyocytes.
Conclusions: Our data demonstrate that cardiac hypertrophy produces dramatically different basal and stress-induced pathophenotypes in female- and male-origin cardiomyocytes. The lower Ca2+ operational status characteristic of female (vs male) cardiomyocytes comprising normal hearts is not exhibited by myocytes of hypertrophic hearts. After ischemia/reperfusion, availability of activator Ca2+ is suppressed in female hypertrophic myocytes, whereas sensitivity to Ca2+ is blunted in male hypertrophic myocytes. These findings demonstrate that selective intervention strategies should be pursued to optimize post-ischemic electromechanical support for male and female hypertrophic hearts.Facultad de Ciencias MédicasCentro de Investigaciones Cardiovasculare
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