2,892 research outputs found
Engineering transport by concatenated maps
We present a generalized kick rotor model in which the phase of the kick can
vary from kick to kick. This additional freedom allows one to control the
transport in phase space. For a specific choice of kick-to-kick phases, we
predict novel forms of accelerator modes which are potentially of high
relevance for future experimental studies
Geophysical and Biological Reconnaissance of Rock Habitats in Western Camden Bay, Beaufort Sea, Alaska
This report presents the results of a 10-day geophysical and
biological survey in western Camden Bay, in the Alaskan Beaufort Sea.
The primary objective of this survey was to confirm the existence of
boulders and cobbles on the seafloor as reported by Barnes (1981, 1982).
The survey area extended from the eastern edge of the Canning River (mud
flat area) to Kangigivik Point and seaward to the 14m contour line
(Fig. 1). A solid boundary of pack ice prevented any survey work
seaward of the 14m contour. We had proposed to examine the seabed to
the 18m contour.This work was
supported by the Bureau of Land Management through an interagency
agreement with the National Oceanic and Atmospheric Administration,
under which a multiyear program responding to needs of petroleum
development of the Alaskan Continental Shelf is managed by the Outer
Continental Shelf Environmental Assessment Program (OCSEAP) office
In situ experiments with synchrotron high-energy x-rays of Ni-Ti alloys produced by powder metallurgy
The structural evolution that takes place during the homogenization heat treatments of powder metallurgical Ni-Ti- alloys was studied by in situ synchrotron diffraction. It is proposed to get a deeper understanding of this phenomenon by using different types of thermal/mechanical cycles
Bringing care to the community: expanding access to health care in rural Malawi through mobile health clinics.
SETTING: Malawi has chronic shortages of health workers, high burdens of human immunodeficiency virus (HIV) infection and malaria and a predominately rural population. Mobile health clinics (MHCs) could provide primary health care for adults and children in hard-to-reach areas. OBJECTIVES: To determine the feasibility, volume, and types of services provided by three MHCs from 2011 to 2013 in Mulanje District, Malawi. DESIGN: Cross-sectional retrospective study. RESULTS: The MHCs conducted 309 492 visits for primary health care, and in 2013 services operated on 99% of planned days. Despite an improvement in service provision, overall patient visits declined over the study period. Malaria and respiratory and gastro-intestinal conditions constituted 60% of visits. Females (n = 11 543) significantly outnumbered males (n = 2481) tested for HIV, yet males tested HIV-positive (27%) more often than females (14%). Malaria accounted for 26 421 (35%) visits for children aged <5 years, with a significant increase in the rainy season. Implementation of rapid diagnostic testing was associated with a decline in numbers treated for malaria. Antibiotic stockouts at government clinics were associated with increased MHC visits. CONCLUSION: MHCs can routinely provide primary health care for adults and children living in rural Malawi and complement fixed clinics. Moving from a complementary role to integration within the government health system remains a challenge
Characterization of a Si(Li) Compton polarimeter for the hard x-ray regime, using synchrotron radiation.
Bringing care to the community: expanding access to health care in rural Malawi through mobile health clinics
Far-infrared study of the Jahn-Teller distorted C60 monoanion in C60 tetraphenylphosphoniumiodide
We report high-resolution far-infrared transmission measurements on C(60)-tetraphenylphosphoniumiodide as a function of temperature. In the spectral region investigated (20-650 cm(-1)), we assign intramolecular modes of the C(60) monoanion and identify low-frequency combination modes. The well-known F(1u)(1) and F(1u)(2) modes are split into doublers at room temperature, indicating a D(5d) or D(3d) distorted ball. This result is consistent with a dynamic Jahn-Teller effect in the strong-coupling limit or with a static distortion stabilized by low-symmetry perturbations. The appearance of silent odd modes is in keeping with symmetry reduction of the hall, while activation of even modes is attributed to interband electron-phonon coupling and orientational disorder in the fulleride salt. Temperature dependences reveal a weak transition in the region 125-150 K in both C(60)(-) and counterion modes, indicating a bulk, rather than solely molecular, effect. Anomalous softening (with decreasing temperature) in several modes may correlate with the radial character of those vibrations. [S0163-1829(98)03245-7]
Control of intestinal stem cell function and proliferation by mitochondrial pyruvate metabolism.
Most differentiated cells convert glucose to pyruvate in the cytosol through glycolysis, followed by pyruvate oxidation in the mitochondria. These processes are linked by the mitochondrial pyruvate carrier (MPC), which is required for efficient mitochondrial pyruvate uptake. In contrast, proliferative cells, including many cancer and stem cells, perform glycolysis robustly but limit fractional mitochondrial pyruvate oxidation. We sought to understand the role this transition from glycolysis to pyruvate oxidation plays in stem cell maintenance and differentiation. Loss of the MPC in Lgr5-EGFP-positive stem cells, or treatment of intestinal organoids with an MPC inhibitor, increases proliferation and expands the stem cell compartment. Similarly, genetic deletion of the MPC in Drosophila intestinal stem cells also increases proliferation, whereas MPC overexpression suppresses stem cell proliferation. These data demonstrate that limiting mitochondrial pyruvate metabolism is necessary and sufficient to maintain the proliferation of intestinal stem cells
- …
