813 research outputs found
The role of pollinators in the floral diversification and life history of Leucospermum (Proteaceae)
Leucospermum, commonly known as pincushions, are an endemic genus often associated with South Africa and, more specifically, the fynbos ecosystem and Cape Floral Kingdom. The staggering floral polymorphism within the genus suggests a wide variety of pollination modes. Despite this remarkable assortment of floral morphologies within Leucospermum only recently has any research been conducted to explain the role of pollinators in driving diversification. In this study we construct the first molecular phylogeny for the genus and, taking relatedness into account using a phylogenetic generalized least squares approach, determine how pollinators have driven floral divergence. Pollinators were assigned through direct observations and a suite of floral traits that are likely to reflect pollination mode were measured for each taxa. In addition, the ability to autonomously self-pollinate was determined for each taxon and used to test if autogamy is linked to specific classes of pollinators, specialized taxa or recently derived taxa. All fieldwork has been finalized and we are awaiting our phylogenetic analysis before any results can be determined
Conservatives moral foundations are more densely connected than liberals’ moral foundations
We use network psychometrics to map a subsection of moral belief systems predicted by moral foundations theory (MFT). This approach conceptualizes moral systems as networks, with moral beliefs represented as nodes connected by direct relations. As such, it advances a novel test of MFT’s claim that liberals and conservatives have different systems of foundational moral values, which we test in three large datasets (N(Sample1) = 854; N(Sample2) = 679; N(Sample3) = 2,572), from two countries (the United States and New Zealand). Results supported our first hypothesis that liberals’ moral systems show more segregation between individualizing and binding foundations than conservatives. Results showed only weak support for our second hypothesis, that this pattern would be more typical of higher educated than less educated liberals/conservatives. Findings support a systems approach to MFT and show the value of modeling moral belief systems as networks
Epidemiological Features of the Selenium Status in Cattle of Northern California
Selenium (Se) is an essential mineral for animal
health. Deficiencies result in white muscle
disease (WMD), retained placenta, and ill thrift in
cattle. These health problems are known to occur
in some northern California herds. This survey was
initiated to provide knowledge on the epidemiological
features of Se deficiency in cattle in this region.
Blood samples were drawn from 10 cows on each
of 10 ranches in each of the northern 22 counties.
Whole blood Se and glutathione peroxidase (GSH-Px)
activities were determined, and these values were
statistically compared with each other and with data
obtained by questionnaire. The latter included
information on animal diseases, soils, forages, and
general ranch descriptors like elevation and rainfall.
The GSH-Px spot test produced either a positive
(+), negative (-) or intermediate (+/-) enzyme
activity classification for each cow. Herd
classification was identified as + or - if > 70%
cow-values fell in that class, otherwise it was identified
as +/-.
The overall geometric mean blood-Se value was
47.6 ng/ml. Regressions of individual and herd
GSH-Px-class against blood-Se values produced
r = .75 and r = .82, respectively. Significantly
low blood-Se levels were recorded in herds with:
1) negative GSH-Px values, 2) past histories of WMD
and ill thrift, 3) predominantly hay diet, 4) pregnant
and early lactating cows, and 5) pure bred
cows. The Se status of herds using Se-salt blocks
was not different from non-supplemented herds. Descriptive
ranch variables did not reliably assess
the Se status of herds in this study
Epidemiological features of the selenium status in cattle of northern California
Selenium (Se) is an essential mineral for animal
health. Deficiencies result in white muscle
disease (40), retained placenta, and ill thrift in
cattle. These health problems are known to occur
in some northern California herds. This survey was
initiated to provide knowledge on the epidemiological
features of Se deficiency in cattle in this region.
Blood samples were drawn from 10 cows on each
of 10 ranches in each of the northern 22 counties.
Whole blood Se and glutathione peroxidase (GBH-Px)
activities were determined, and these values were
statistically compared with each other and with data
obtained by questionnaire. The latter included
information on animal diseases, soils, forages, and
general ranch descriptors like elevation and rainfall.
The GSH-Px spot test produced either a positive
(+), negative (-) or intermediate (+/-) enzyme
activity classification for each cow. Herd
classification was identified as + or - if >70%
cow-values fell in that class, otherwise it was identified
as +/-.
The overall geometric mean blood-Se value was
47.6 ng/ml. Regressions of individual and herd
GSH-Px-class against blood-Se values produced
r = .75 and r = .82, respectively. Significantly
low blood-Se levels were recorded in herds with:
1) negative GSH-Px values, 2) past histories of WMD
and ill thrift, 3) predominantly hay diet, 4) pregnant
and early lactating cows, and 5) pure bred
cows. The Se status of herds using Se-salt blocks
was not different from non- supplemented herds. Descriptive
ranch variables did not reliably assess
the Se status of herds in this study
Transverse instability and its long-term development for solitary waves of the (2+1)-Boussinesq equation
The stability properties of line solitary wave solutions of the
(2+1)-dimensional Boussinesq equation with respect to transverse perturbations
and their consequences are considered. A geometric condition arising from a
multi-symplectic formulation of this equation gives an explicit relation
between the parameters for transverse instability when the transverse
wavenumber is small. The Evans function is then computed explicitly, giving the
eigenvalues for transverse instability for all transverse wavenumbers. To
determine the nonlinear and long time implications of transverse instability,
numerical simulations are performed using pseudospectral discretization. The
numerics confirm the analytic results, and in all cases studied, transverse
instability leads to collapse.Comment: 16 pages, 8 figures; submitted to Phys. Rev.
Iron under Earth's core conditions: Liquid-state thermodynamics and high-pressure melting curve
{\em Ab initio} techniques based on density functional theory in the
projector-augmented-wave implementation are used to calculate the free energy
and a range of other thermodynamic properties of liquid iron at high pressures
and temperatures relevant to the Earth's core. The {\em ab initio} free energy
is obtained by using thermodynamic integration to calculate the change of free
energy on going from a simple reference system to the {\em ab initio} system,
with thermal averages computed by {\em ab initio} molecular dynamics
simulation. The reference system consists of the inverse-power pair-potential
model used in previous work. The liquid-state free energy is combined with the
free energy of hexagonal close packed Fe calculated earlier using identical
{\em ab initio} techniques to obtain the melting curve and volume and entropy
of melting. Comparisons of the calculated melting properties with experimental
measurement and with other recent {\em ab initio} predictions are presented.
Experiment-theory comparisons are also presented for the pressures at which the
solid and liquid Hugoniot curves cross the melting line, and the sound speed
and Gr\"{u}neisen parameter along the Hugoniot. Additional comparisons are made
with a commonly used equation of state for high-pressure/high-temperature Fe
based on experimental data.Comment: 16 pages including 6 figures and 5 table
Space-time evolution of hadronization
Beside its intrinsic interest for the insights it can give into color
confinement, knowledge of the space-time evolution of hadronization is very
important for correctly interpreting jet-quenching data in heavy ion collisions
and extracting the properties of the produced medium. On the experimental side,
the cleanest environment to study the space-time evolution of hadronization is
semi-inclusive Deeply Inelastic Scattering on nuclear targets. On the
theoretical side, 2 frameworks are presently competing to explain the observed
attenuation of hadron production: quark energy loss (with hadron formation
outside the nucleus) and nuclear absorption (with hadronization starting inside
the nucleus). I discuss recent observables and ideas which will help to
distinguish these 2 mechanisms and to measure the time scales of the
hadronization process.Comment: 6 pages, 4 figures. Based on talks given at "Hot Quarks 2006",
Villasimius, Italy, May 15-20, 2006, and at the "XLIV internataional winter
meeting on nuclear physics", Bormio, Italy, Jan 29 - Feb 5, 2006. To appear
in Eur.Phys.J.
On the fourth-order accurate compact ADI scheme for solving the unsteady Nonlinear Coupled Burgers' Equations
The two-dimensional unsteady coupled Burgers' equations with moderate to
severe gradients, are solved numerically using higher-order accurate finite
difference schemes; namely the fourth-order accurate compact ADI scheme, and
the fourth-order accurate Du Fort Frankel scheme. The question of numerical
stability and convergence are presented. Comparisons are made between the
present schemes in terms of accuracy and computational efficiency for solving
problems with severe internal and boundary gradients. The present study shows
that the fourth-order compact ADI scheme is stable and efficient
From Social Data Mining to Forecasting Socio-Economic Crisis
Socio-economic data mining has a great potential in terms of gaining a better
understanding of problems that our economy and society are facing, such as
financial instability, shortages of resources, or conflicts. Without
large-scale data mining, progress in these areas seems hard or impossible.
Therefore, a suitable, distributed data mining infrastructure and research
centers should be built in Europe. It also appears appropriate to build a
network of Crisis Observatories. They can be imagined as laboratories devoted
to the gathering and processing of enormous volumes of data on both natural
systems such as the Earth and its ecosystem, as well as on human
techno-socio-economic systems, so as to gain early warnings of impending
events. Reality mining provides the chance to adapt more quickly and more
accurately to changing situations. Further opportunities arise by individually
customized services, which however should be provided in a privacy-respecting
way. This requires the development of novel ICT (such as a self- organizing
Web), but most likely new legal regulations and suitable institutions as well.
As long as such regulations are lacking on a world-wide scale, it is in the
public interest that scientists explore what can be done with the huge data
available. Big data do have the potential to change or even threaten democratic
societies. The same applies to sudden and large-scale failures of ICT systems.
Therefore, dealing with data must be done with a large degree of responsibility
and care. Self-interests of individuals, companies or institutions have limits,
where the public interest is affected, and public interest is not a sufficient
justification to violate human rights of individuals. Privacy is a high good,
as confidentiality is, and damaging it would have serious side effects for
society.Comment: 65 pages, 1 figure, Visioneer White Paper, see
http://www.visioneer.ethz.c
Evidence of Final-State Suppression of High-p_T Hadrons in Au + Au Collisions Using d + Au Measurements at RHIC
Transverse momentum spectra of charged hadrons with 6 GeV/c have
been measured near mid-rapidity (0.2 1.4) by the PHOBOS experiment
at RHIC in Au + Au and d + Au collisions at . The spectra for different collision centralities are compared to collisions at the same energy. The resulting nuclear modification
factor for central Au + Au collisions shows evidence of strong suppression of
charged hadrons in the high- region ( GeV/c). In contrast, the d +
Au nuclear modification factor exhibits no suppression of the high-
yields. These measurements suggest a large energy loss of the high-
particles in the highly interacting medium created in the central Au + Au
collisions. The lack of suppression in d + Au collisions suggests that it is
unlikely that initial state effects can explain the suppression in the central
Au + Au collisions.Comment: 3 pages, 4 figures, International Europhysics Conference on High
Energy Physics EPS (July 17th-23rd 2003) in Aachen, German
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