963 research outputs found
Badania szkodliwego wpływu czynników antropogenicznych na karpia za pomocą pomiarów niektórych parametrów biochemicznych
Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej naukę
Variables Affecting Measurements of Vertical Occlusal Force
Previous studies of occlusal force have provided conflicting results. The purpose of these studies was to determine whether the extent of vertical opening, contralateral occlusal support, or head posture influenced vertical occlusal forces during swallowing, simulated chewing, and maximum biting effort. Three samples of subjects with normal vertical facial proportions - one each of children, adolescents, and young adults - were evaluated to determine the effects of changes in small (2.5 vs. 6.0 mm) vertical separation of the first molars. A sample of young adults was used to evaluate changes in large (10-40 mm) vertical openings, and a sample of adolescents was used to investigate the effect of contralateral support and head posture. All between-group comparisons were evaluated using non-parametric statistics. For the small vertical openings, there was significantly more vertical occlusal force at 6.0 than 2.5 mm in children during swallowing and chewing but not during maximum biting effort. In adults, there was significantly more force during swallowing at 6.0 than at 2.5 mm separation, but no differences in chewing or maximum biting. Increasingly large vertical openings resulted in a progressive increase in maximum bite force to a maximum at about 20 mm, followed by a decrease and then a second increase to near-maximum force at about 40 mm for young adults. There were no significant differences in vertical force with or without contralateral support or between flexed, normal, and extended head postures at either of the small openings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/68036/2/10.1177_00220345860650020901.pd
Probabilistic Classification of Infrared-selected targets for SPHEREx mission: In search of YSOs
We apply machine learning algorithms to classify Infrared (IR)-selected
targets for NASA's upcoming SPHEREx mission. In particular, we are interested
in classifying Young Stellar Objects (YSOs), which are essential for
understanding the star formation process. Our approach differs from previous
work, which has relied heavily on broadband color criteria to classify
IR-bright objects, and are typically implemented in color-color and
color-magnitude diagrams. However, these methods do not state the confidence
associated with the classification and the results from these methods are quite
ambiguous due to the overlap of different source types in these diagrams. Here,
we utilize photometric colors and magnitudes from seven near and mid-infrared
bands simultaneously and employ machine and deep learning algorithms to carry
out probabilistic classification of YSOs, Asymptotic Giant Branch (AGB) stars,
Active Galactic Nuclei (AGN) and main-sequence (MS) stars. Our approach also
sub-classifies YSOs into Class I, II, III and flat spectrum YSOs, and AGB stars
into carbon-rich and oxygen-rich AGB stars. We apply our methods to
infrared-selected targets compiled in preparation for SPHEREx which are likely
to include YSOs and other classes of objects. Our classification indicates that
out of sources, have class prediction with probability
exceeding , amongst which are YSOs, are AGB
stars, are (reddened) MS stars, and are AGN whose red
broadband colors mimic YSOs. We validate our classification using the spatial
distributions of predicted YSOs towards the Cygnus-X star-forming complex, as
well as AGB stars across the Galactic plane.Comment: 17 pages, 12 figures, Accepted for publication in MNRA
Surface collective modes in the topological insulators BiSe and BiSbTeSe
We used low-energy, momentum-resolved inelastic electron scattering to study
surface collective modes of the three-dimensional topological insulators
BiSe and BiSbTeSe. Our goal was to
identify the "spin plasmon" predicted by Raghu and co-workers [S. Raghu, et
al., Phys. Rev. Lett. 104, 116401 (2010)]. Instead, we found that the primary
collective mode is a surface plasmon arising from the bulk, free carrers in
these materials. This excitation dominates the spectral weight in the bosonic
function of the surface, , at THz energy scales, and
is the most likely origin of a quasiparticle dispersion kink observed in
previous photoemission experiments. Our study suggests that the spin plasmon
may mix with this other surface mode, calling for a more nuanced understanding
of optical experiments in which the spin plasmon is reported to play a role.Comment: 5 pages, 4 figure
A necklace of dense cores in the high-mass star forming region G35.20-0.74N: ALMA observations
The present study aims at characterizing the massive star forming region
G35.20N, which is found associated with at least one massive outflow and
contains multiple dense cores, one of them recently found associated with a
Keplerian rotating disk. We used ALMA to observe the G35.20N region in the
continuum and line emission at 350 GHz. The observed frequency range covers
tracers of dense gas (e.g. H13CO+, C17O), molecular outflows (e.g. SiO), and
hot cores (e.g. CH3CN, CH3OH). The ALMA 870 um continuum emission map reveals
an elongated dust structure (0.15 pc long and 0.013 pc wide) perpendicular to
the large-scale molecular outflow detected in the region, and fragmented into a
number of cores with masses 1-10 Msun and sizes 1600 AU. The cores appear
regularly spaced with a separation of 0.023 pc. The emission of dense gas
tracers such as H13CO+ or C17O is extended and coincident with the dust
elongated structure. The three strongest dust cores show emission of complex
organic molecules characteristic of hot cores, with temperatures around 200 K,
and relative abundances 0.2-2x10^(-8) for CH3CN and 0.6-5x10^(-6) for CH3OH.
The two cores with highest mass (cores A and B) show coherent velocity fields,
with gradients almost aligned with the dust elongated structure. Those velocity
gradients are consistent with Keplerian disks rotating about central masses of
4-18 Msun. Perpendicular to the velocity gradients we have identified a
large-scale precessing jet/outflow associated with core B, and hints of an
east-west jet/outflow associated with core A. The elongated dust structure in
G35.20N is fragmented into a number of dense cores that may form massive stars.
Based on the velocity field of the dense gas, the orientation of the magnetic
field, and the regularly spaced fragmentation, we interpret this elongated
structure as the densest part of a 1D filament fragmenting and forming massive
stars.Comment: 24 pages, 26 figures, accepted for publication in Astronomy and
Astrophysics (abstract modified to fit arXiv restrictions
Phosphoramidates and phosphonamidates (ProTides) with antiviral activity
Following the first report on the nucleoside phosphoramidate (ProTide) prodrug approach in 1990 by Chris McGuigan, the extensive investigation of ProTide technology has begun in many laboratories. Designed with aim to overcome limitations and the key resistance mechanisms associated with nucleoside analogues used in the clinic (poor cellular uptake, poor conversion to the 5′-monophosphate form), the ProTide approach has been successfully applied to a vast number of nucleoside analogues with antiviral and anticancer activity. ProTides consist of a 5′-nucleoside monophosphate in which the two hydroxyl groups are masked with an amino acid ester and an aryloxy component which once in the cell is enzymatically metabolized to deliver free 5′-monophosphate, which is further transformed to the active 5′-triphosphate form of the nucleoside analogue. In this review, the seminal contribution of Chris McGuigan’s research to this field is presented. His technology proved to be extremely successful in drug discovery and has led to two Food and Drug Administration-approved antiviral agents
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