14,067 research outputs found
Celtic Explorer Cruise CE10005, 16-24 Sep 2010, Milford Haven, UK to Galway, Ireland. Porcupine Abyssal Plain Observatory servicing
The principal objective was to maintain the Porcupine Abyssal Plain (PAP) observatory infrastructure. The main components of this are:-• A large ODAS buoy mooring (PAP 1) with real time telemetry and multiple underwater and meteorological sensors. The buoy and sensor frame will be recovered and most of the sensors and telemetry systems replaced, before redeployment.• A sediment trap mooring (PAP 3). This mooring will be recovered and replaced with a new one.• A Bathysnap camera lander. To be recovered and replaced.Associated work will include CTD sensor calibration dips and deployment of 2 ARGO floats. The work proposed will be vital to maintaining the long standing time-series measurements at this site, and will also provide critical feedback on sensor and mooring design performance.This cruise was originally conceived as a key component of the MODOO (MOdular Deep Ocean Observatory) ESONET demonstration project http://www.modoo.info/ . The main partof this project was a BoBo lander belonging to NIOZ that was deployed at the same time as the ODAS buoy in June 2010. This lander should have been recovered during CE10005 to obtain in-situ data from the lander and to assess the performance of the acoustic telemetry system. Unfortunately the lander appears to have suffered an implosion shortly after deployment, and one objective of this cruise will now be to attempt to communicate with the lander’s acoustic releases.An ancillary task led by Marine Institute (MI) involves the collection of samples as part of the Marine Biodiscovery project in NUI, Galway. The aim of this research is to investigate the possibility that phytoplankton species in Irish waters can produce biologically active compounds (bioactives) of significance for use as human medicines
A Phase Model with Large Time Delayed Coupling
We consider two identical oscillators with weak, time delayed coupling. We
start with a general system of delay differential equations then reduce it to a
phase model. With the assumption of large time delay, the resulting phase model
has an explicit delay and phase shift in the argument of the phases and
connection function, respectively. Using the phase model, we prove that for any
type of oscillators and any coupling, the in-phase and anti-phase phase-locked
solutions always exist and give conditions for their stability. We show that
for small delay these solutions are unique, but with large enough delay
multiple solutions of each type with different frequencies may occur. We give
conditions for the existence and stability of other types of phase-locked
solutions. We discuss the various bifurcations that can occur in the phase
model as the time delay is varied. The results of the phase model analysis are
applied to Morris-Lecar oscillators with diffusive coupling and compared with
numerical studies of the full system of delay differential equations. We also
consider the case of small time delay and compare the results with the existing
ones in the literature
Developing growth mindsets in engineering students: Work-in-progress on a systematic literature review
Engineering programs can be very demanding, particularly in the first years where
students often encounter challenging coursework. Dropout from engineering studies
has been linked to ‘fixed mindset’ beliefs that make students more likely to give up
when facing new challenges. Extensive research evidenced that students with a ‘fixed
mindset’ believe that intelligence is an innate and fixed trait. In contrast, students with
a ‘growth mindset’ believe that intelligence can be improved with effort and drive, and
are then less likely to disengage when confronting difficult tasks. Interventions to
develop ‘growth mindsets’ have been successfully implemented at primary and
secondary schools. However, there seems to be a paucity of interventions with
university students studying engineering. In this work-in-progress paper, we will
present findings from a systematic literature review of engineering, education and
psychology databases to answer the question, ‘What interventions to develop growth
mindsets have been implemented with engineering students, and what measures have
been used to assess the effectiveness of the interventions?’ Preliminary findings suggest that the number of interventions aimed at strengthening growth mindsets in
engineering students is still small. We present a categorization of interventions
together with the measures used to assess the effectiveness of the interventions. The
findings will be useful for engineering educators who want to encourage students to
have the benefits associated with a growth mindset, such as greater resilience after
setbacks and willingness to take on challenges and stick with them when difficulties
arise, and support their academic success
Developing growth mindsets in engineering students: a systematic literature review of interventions
Dropout from engineering studies has been linked to ‘fixed mindset’ beliefs of intelligence as fixed-at-birth that make students more likely to disengage when facing new challenges. In contrast, ‘growth mindset’ beliefs that intelligence can be improved with effort make students more likely to persist when confronting difficulties. This systematic literature review of engineering, education and psychology databases explores the effectiveness of different interventions in developing growth mindset in engineering students, what measures have been used in assessing the effectiveness of these interventions and who has benefited from these interventions, in terms of gender and year of study. We compare interventions by geographical location, intervention type, methodology for assessing mindsets, other topics studied, and effectiveness. The results show a variation in effectiveness among the fifteen included studies. The findings will be useful for educators who want to encourage growth mindset and thereby support the academic success of their students
M-current Induced Bogdanov-Takens Bifurcation and Switching of Neuron Excitability Class
In this work, we consider a general conductance-based neuron model with the
inclusion of the acetycholine sensitive, M-current. We study bifurcations in
the parameter space consisting of the applied current, the maximal
conductance of the M-current, , and the conductance of the leak current,
. We give precise conditions for the model that ensure the existence of a
Bogdanov-Takens (BT) point and show such a point can occur by varying
and . We discuss the case when the BT point becomes a
Bogdanov-Takens-Cusp (BTC) point and show that such a point can occur in the
three dimensional parameter space. The results of the bifurcation analysis are
applied to different neuronal models and are verified and supplemented by
numerical bifurcation diagrams generated using the package MATCONT. We conclude
that there is a transition in the neuronal excitability type organized by the
BT point and the neuron switches from Class-I to Class-II as conductance of the
M-current increases
Understanding graduation rates at higher education institutions: A forecasting model
Graduation rates and degree completion have always been a concern for students, students’ families and universities. Moreover, many consider college degree completion rates to be among one of the most important indicators of institutional quality according to a report from the Higher Education Research Institute published in the United States of America. This research studied factors that can explain graduation rates which include student‐faculty ratio, financial factors, and enrollment status. Data was collected and analyzed for state and private universities, and a Multiple Regression Model (MLR) was built to forecast graduation rates. The model was able to highlight variables that significantly relate to graduation rates. Researchers can use this article to understand the different factors that correlate with degree completion and to forecast graduations rates at Higher Education Institutions. The international researcher can explore replicating the forecasting model at universities outside the United States of America
Ocean acidification changes the male fitness landscape.
Sperm competition is extremely common in many ecologically important marine taxa. Ocean acidification (OA) is driving rapid changes to the marine environments in which freely spawned sperm operate, yet the consequences of OA on sperm performance are poorly understood in the context of sperm competition. Here, we investigated the impacts of OA (+1000 μatm pCO2) on sperm competitiveness for the sea urchin Paracentrotus lividus. Males with faster sperm had greater competitive fertilisation success in both seawater conditions. Similarly, males with more motile sperm had greater sperm competitiveness, but only under current pCO2 levels. Under OA the strength of this association was significantly reduced and there were male sperm performance rank changes under OA, such that the best males in current conditions are not necessarily best under OA. Therefore OA will likely change the male fitness landscape, providing a mechanism by which environmental change alters the genetic landscape of marine species.We acknowledge Catherina Artikis and Yueling Hao for their contributions to the molecular analysis. We thank
the team at Exeter Biosciences for their help and support. A.L.C. was supported by a Natural Environment
Research Council (NERC) PhD studentship to Exeter, and received additional funding from Exeter CLES
PREF and a Santander Postgraduate Research Award (2014/2015). C.L. was supported by a UK-OARP NERC
consortium grant NE/H017496/1 and a NERC UK Fellowship: NE/G014728/1. DRL was supported by funding
from the United States, National Science Foundation (Grant DEB 1354272) which helped to fund the molecular
analysis
Distributed Delay and Desynchronization in a Brain Network Model
We consider a neural field model which consists of a network of an arbitrary
number of Wilson-Cowan nodes with homeostatic adjustment of the inhibitory
coupling strength and time delayed, excitatory coupling. We extend previous
work on this model to include distributed time delays with commonly used kernel
distributions: delta function, uniform distribution and gamma distribution.
Focussing on networks which satisfy a constant row sum condition, we show how
each eigenvalue of the connectivity matrix may be related to a Hopf bifurcation
and that the eigenvalue determines whether the bifurcation leads to
synchronized or desynchronized oscillatory behaviour. We consider two example
networks, one with all real eigenvalues (bi-directional ring) and one with some
complex eigenvalues (uni-directional ring). In bi-directional rings, the Hopf
curves are organized so that only the synchronized Hopf leads to asymptotically
stable behaviour. Thus the behaviour in the network is always synchronous. In
the uni-directional ring networks, however, intersection points of asynchronous
and synchronous Hopf curves may occur resulting in double Hopf bifurcation
points. Thus asymptotically stable synchronous and asynchronous limit cycles
can occur as well as torus-like solutions which combine synchronous and
asynchronous behaviour. Increasing the size of the network or the mean time
delay makes these intersection points, and the associated asynchronous
behaviour, more likely to occur. Numerical approaches are used to confirm the
findings, with Hopf bifurcation curves plotted using Wolfram Mathematica. These
insights offer a deeper understanding of the mechanisms underlying
desynchronization in large networks of oscillators
Supporting the Critical Administrative Leadership Role of County Directors
With a foot in both the university and local communities, Cooperative Extension county directors have unique opportunities to network, scan opportunities, identify assets, design and market programs, build public support, and solve problems. A survey of the administrative workload, satisfactions, and frustrations of California county directors finds these leadership roles are insufficiently supported. The data suggest the need to 1) alter merit review policies to reward community connections and networking, 2) reinvent university support bureaucracies to treat county directors as valued customers, and 3) reassert a robust vision of county-based Extension at the highest levels of the organization
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