1,255 research outputs found
The effects of salivas on occlusal forces
Contacting surfaces of opposing teeth produce friction that, when altered, changes the contact force direction and/or magnitude. As friction can be influenced by several factors, including lubrication and the contacting materials, the aim of this study was to measure the occlusal load alterations experienced by teeth with the introduction of different salivas and dental restorative materials. Pairs of molar teeth were set into occlusion with a weighted maxillary tooth mounted onto a vertical sliding assembly and the mandibular tooth supported by a load cell. The load components on the mandibular tooth were measured with three opposing pairs of dental restorative materials (plastic denture, all-ceramic and stainless steel), four (human and three artificial) salivas and 16 occlusal configurations. All lateral force component measurements were significantly different (P < 0·0001) from the dry (control) surface regardless of the crown material or occlusal configuration, while the effects of the artificial salivas compared to each other and to human saliva depended on the crown material
Managing racial diversity: matching internal strategies to environmental needs
Although demographic diversity has been of paramount concern to researchers and practitioners in public management, studies exploring managerial strategies to capitalize on and respond to the needs of diverse client populations are scarce. This article examines strategies for managing diversity as a way to buffer environmental challenges in service delivery and performance resulting from heterogeneous client demands. Findings suggest that administrators prioritize diversity efforts when faced with higher levels of regulatory violations (a performance measure). A higher percentage of black residents is associated with lower service quality. However, the effect of managerial strategies for diversity on performance is conditioned by the racial composition of the clients: as the percentage of black nursing home residents increases, diversity management efforts are associated with a lower number of regulatory violations. Similarly, at higher levels of racial heterogeneity, diversity management efforts are associated with fewer regulatory violations
Facilitating human-wildlife interactions in conservation translocations
Workshop:
Species reintroductions and translocations are widely used management interventions to restore locally extinct or augment severely depleted species. In such projects, the human dimension issues that influence reintroductions and translocations success are encountered at five different stages of the project life cycle: 1) The pre-project phase 2) At the start, 3) During implementation 4) At the end of the project and 5) Post-project. Whenever any of these are overlooked or treated lightly the result may jeopardise the success of the reintroduction/translocation project. Investments in human-dimension aspects improve community involvement, peersâ acceptance and the support from various interest groups.
The Human-Wildlife Interactions Working Group (HWIWG) was formed in 2018 by members of the IUCN/SSC Conservation Translocation Specialist Group (CTSG). The group has facilitated online discussions and webinars with practitioners, researchers and academics from across the globe, on a wide variety of topics concerning human dimensions of reintroductions. In this workshop we propose to discuss with participants their experiences in human dimensions of conservation translocations in relation to each of 5 proposed stages of a projectâs life cycle.  Discussions will be guided by findings from the HWIWG so that participants may identify best practice and key issues in considering human-dimension in each of these 5 stages to inform planning and promote conservation, collaboration amongst groups and coexistence
The Gravitational Field of a Rotating Infinite Cylindrical Shell
Israel's method for treating surface layers is applied to determine the gravitational field due to a rotating cylindrical shell. The interior spacetime is flat while the exterior metric can be one of three types. For a given value of the stress in the cylinder, the type of the exterior metric depends on the mass per unit co-ordinate length of the cylinder
Open models for removal data
Individuals of protected species, such as amphibians and reptiles, often need to be removed from sites before development commences. Usually, the population is considered to be closed. All individuals are assumed to i) be present and available for detection at the start of the study period and ii) remain at the site until the end of the study, unless they are detected. However, the assumption of population closure is not always valid. We present new removal models which allow for population renewal through birth and/or immigration, and population depletion through sampling as well as through death/emigration. When appropriate, productivity may be estimated and a Bayesian approach allows the estimation of the probability of total population depletion. We demonstrate the performance of the models using data on common lizards, Zootoca vivipara, and great crested newts, Triturus cristatus
The Clusters AgeS Experiment (CASE). II. The Eclipsing Blue Straggler OGLEGC-228 in the Globular Cluster 47 Tuc
We use photometric and spectroscopic observations of the eclipsing binary
OGLEGC-228 (V228) to derive the masses, radii, and luminosities of the
component stars. Based on measured systemic velocity, proper motion and
distance, the system is a blue straggler member of the globular cluster 47 Tuc.
Our analysis shows that V228 is a semi-detached Algol. We obtain M=1.512 +/-
0.022 Msun, R=1.357 +/- 0.019 Rsun, L=7.02 +/- 0.050 Lsun for the hotter and
more luminous primary component and M=0.200 +/- 0.007 Msun, R=1.238 +/- 0.013
Rsun, L=1.57 +/- 0.09 Lsun for the Roche lobe filling secondary.Comment: 19 pages, 5 figures, AJ, in pres
The "Mysterious" Origin of Brown Dwarfs
Hundreds of brown dwarfs (BDs) have been discovered in the last few years in
stellar clusters and among field stars. BDs are almost as numerous as hydrogen
burning stars and so a theory of star formation should also explain their
origin. The ``mystery'' of the origin of BDs is that their mass is two orders
of magnitude smaller than the average Jeans' mass in star--forming clouds, and
yet they are so common. In this work we investigate the possibility that
gravitationally unstable protostellar cores of BD mass are formed directly by
the process of turbulent fragmentation. Supersonic turbulence in molecular
clouds generates a complex density field with a very large density contrast. As
a result, a fraction of BD mass cores formed by the turbulent flow are dense
enough to be gravitationally unstable. We find that with density, temperature
and rms Mach number typical of cluster--forming regions, turbulent
fragmentation can account for the observed BD abundance.Comment: 11 pages, 3 figures, ApJ submitted Error in equation 1 has been
corrected. Improved figure
The surprising external upturn of the Blue Straggler radial distribution in M55
By combining high-resolution HST and wide-field ground based observations, in
ultraviolet and optical bands, we study the Blue Straggler Star (BSS)
population of the low density galactic globular cluster M55 (NGC 6809) over its
entire radial extent. The BSS projected radial distribution is found to be
bimodal, with a central peak, a broad minimum at intermediate radii, and an
upturn at large radii. Similar bimodal distributions have been found in other
globular clusters (M3, 47 Tucanae, NGC 6752, M5), but the external upturn in
M55 is the largest found to date. This might indicate a large fraction of
primordial binaries in the outer regions of M55, which seems somehow in
contrast with the relatively low (\sim 10%) binary fraction recently measured
in the core of this cluster.Comment: in press on Ap
Let's talk about varying G
It is possible that fundamental constants may not be constant at all. There
is a generally accepted view that one can only talk about variations of
dimensionless quantities, such as the fine structure constant . However, constraints on the strength of
gravity tend to focus on G itself, which is problematic. We stress that G needs
to be multiplied by the square of a mass, and hence, for example, one should be
constraining , where is
the proton mass. Failure to focus on such dimensionless quantities makes it
difficult to interpret the physical dependence of constraints on the variation
of G in many published studies. A thought experiment involving talking to
observers in another universe about the values of physical constants may be
useful for distinguishing what is genuinely measurable from what is merely part
of our particular system of units.Comment: 6 pages, Gravity Research Foundation essa
- âŠ