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Dielectrophoretic Manipulation of Particles and Lymphocytes
This paper was presented at the 4th Micro and Nano Flows Conference (MNF2014), which was held at University College, London, UK. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute, ASME Press, LCN London Centre for Nanotechnology, UCL University College London, UCL Engineering, the International NanoScience Community, www.nanopaprika.eu.A particle manipulation and sorting device using the dielectrophoretic (DEP) force is described in this study. The device consists of “ladder-type”, “flip-type” and “oblique rail-type” electrode regions. The ladder-type and rail-type electrodes can generate a DEP force distribution that captures the particles, the DEP force of which is “negative” (repulsion force), in the area located at the center of the electrodes. The particles can then be guided individually along the electrode. In addition to this, the ladder-type electrode can align the particles with equal spacing in the streamwise direction. Using the “flip-type” electrode, which pushes the particles away, in combination with these electrodes, the direction of the particle can be selected with high accuracy, reliability and response. In the first half of this paper, numerical simulation was carried out to calculate the particle motion and evaluate the performance of the ladder-type electrode. Several models were validated to investigate the influences of the non-uniformity of the electric field and the electric interaction of the surface charges and polarizations. Measurement using the high-speed camera was then carried out to investigate the motions of the particles and sorting reliability. The trajectories and the probability density functions of the particles at the inlet and outlet of the electrode region showed that by using these electrodes the particles can be aligned, sorted and guided accurately
Searching for Composite Neutrinos in the Cosmic Microwave Background
We analyze signals in the Cosmic Microwave Background (CMB) in theories where
the small Dirac neutrino masses arise as a consequence of the compositeness of
right-handed neutrinos. In such theories, the right-handed neutrinos are
massless ``baryons'' of a new strong gauge interaction. We find that the
results crucially depend on whether or not the new strong sector undergoes
chiral symmetry breaking. In the case with chiral symmetry breaking, we find
that there are indeed signals in the CMB, but none of them is a direct
consequence of neutrino compositeness. In contrast, if the underlying theory
does not undergo chiral symmetry breaking, the large scattering cross-section
among the composites gives rise to a sizable CMB signal over a wide region of
the parameter space, and it can potentially probe whether the neutrino mass
spectrum is hierarchical, inverse hierarchical, or degenerate. We also discuss
collider constraints on the compositeness in the context of the CMB signals.Comment: 26 pages. References and clarifying comments added. Version appearing
to JHE
CMB Signals of Neutrino Mass Generation
We propose signals in the cosmic microwave background to probe the type and
spectrum of neutrino masses. In theories that have spontaneous breaking of
approximate lepton flavor symmetries at or below the weak scale, light
pseudo-Goldstone bosons recouple to the cosmic neutrinos after nucleosynthesis
and affect the acoustic oscillations of the electron-photon fluid during the eV
era. Deviations from the Standard Model are predicted for both the total energy
density in radiation during this epoch, \Delta N_nu, and for the multipole of
the n'th CMB peak at large n, \Delta l_n. The latter signal is difficult to
reproduce other than by scattering of the known neutrinos, and is therefore an
ideal test of our class of theories. In many models, the large shift, \Delta
l_n \approx 8 n_S, depends on the number of neutrino species that scatter via
the pseudo-Goldstone boson interaction. This interaction is proportional to the
neutrino masses, so that the signal reflects the neutrino spectrum. The
prediction for \Delta N_nu is highly model dependent, but can be accurately
computed within any given model. It is very sensitive to the number of
pseudo-Goldstone bosons, and therefore to the underlying symmetries of the
leptons, and is typically in the region of 0.03 < \Delta N_nu < 1. This signal
is significantly larger for Majorana neutrinos than for Dirac neutrinos, and,
like the scattering signal, varies as the spectrum of neutrinos is changed from
hierarchical to inverse hierarchical to degenerate.Comment: 40 pages, 4 figure
The LHC Phenomenology of Vectorlike Confinement
We investigate in detail the LHC phenomenology of "vectorlike confinement",
where the Standard Model is augmented by a new confining gauge interaction and
new light fermions that carry vectorlike charges under both the Standard Model
and the new gauge group. If the new interaction confines at the TeV scale, this
framework gives rise to a wide range of exotic collider signatures such as the
production of a vector resonance that decays to a pair of collider-stable
charged massive particles (a "di-CHAMP" resonance), to a pair of
collider-stable massive colored particles (a "di-R-hadron resonance), to
multiple photons, s and s via two intermediate scalars, and/or to
multi-jet final states. To study these signals at the LHC, we set up two
benchmark models: one for the di-CHAMP and multi-photon signals, and the other
for the di-R-hadron and multijet signals. For the di-CHAMP/multi-photon model,
Standard Model backgrounds are negligible, and we show that a full
reconstruction of the spectrum is possible, providing powerful evidence for
vectorlike confinement. For the di-R-hadron/multijet model, we point out that
in addition to the di-R-hadron signal, the rate of the production of four
R-hadrons can also be sizable at the LHC. This, together with the multi-jet
signals studied in earlier work, makes it possible to single out vectorlike
confinement as the underlying dynamics.Comment: 32 pages, 28 figures. Several typos fixed, one paragraph added
elaborating choice of benchmarks. Version accepted by JHEP
Changes in utilization of health services among poor and rural residents in Uganda: are reforms benefitting the poor?
Exploring new health markets: experiences from informal providers of transport for maternal health services in Eastern Uganda
<p>Abstract</p> <p>Background</p> <p>Although a number of intermediate transport initiatives have been used in some developing countries, available evidence reveals a dearth of local knowledge on the effect of these rural informal transport mechanisms on access to maternal health care services, the cost of implementing such schemes and their scalability. This paper, attempts to provide insights into the functioning of the informal transport markets in facilitating access to maternal health care. It also demonstrates the role that higher institutions of learning can play in designing projects that can increase the utilization of maternal health services.</p> <p>Objectives</p> <p>To explore the use of intermediate transport mechanisms to improve access to maternal health services, with emphasis on the benefits and unintended consequences of the transport scheme, as well as challenges in the implementation of the scheme.</p> <p>Methods</p> <p>This paper is based on the pilot phase to inform a quasi experimental study aimed at increasing access to maternal health services using demand and supply side incentives. The data collection for this paper included qualitative and quantitative methods that included focus group interviews, review of project documents and facility level data.</p> <p>Results</p> <p>There was a marked increase in attendance of antenatal, and delivery care services, with the contracted transporters playing a leading role in mobilizing mothers to attend services. The project also had economic spill-over effects to the transport providers, their families and community generally. However, some challenges were faced including difficulty in setting prices for paying transporters, and poor enforcement of existing traffic regulations.</p> <p>Conclusions and implications</p> <p>The findings indicate that locally existing resources such as motorcycle riders, also known as “boda boda” can be used innovatively to reduce challenges caused by geographical inaccessibility and a poor transport network with resultant increases in the utilization of maternal health services. However, care must be taken to mobilize the resources needed and to ensure that there is enforcement of laws that will ensure the safety of clients and the transport providers themselves.</p
ODTN: Open Disaggregated Transport Network. Discovery and Control of a Disaggregated Optical Network through Open Source Software and Open APIs
ONOS discovers and manages a topology made of Transponders and a dedicated OLS, using standard protocols (NETCONF/RESTCONF) and models (OpenConfig/TAPI). The demo is a joint collaboration, towards production deployment, between 3 operators and 2 equipment vendors
Building partnerships towards strengthening Makerere University College of Health Sciences: a stakeholder and sustainability analysis
<p>Abstract</p> <p>Background</p> <p>Partnerships and networking are important for an institution of higher learning like Makerere University College of Health Sciences (MakCHS) to be competitive and sustainable.</p> <p>Methods</p> <p>A stakeholder and sustainability analysis of 25 key informant interviews was conducted among past, current and potential stakeholders of MakCHS to obtain their perspectives and contributions to sustainability of the College in its role to improve health outcomes.</p> <p>Results</p> <p>The College has multiple internal and external stakeholders. Stakeholders from Uganda wanted the College to use its enormous academic capacity to fulfil its vision, take initiative, and be innovative in conducting more research and training relevant to the country’s health needs. Many stakeholders felt that the initiative for collaboration currently came more from the stakeholders than the College. External stakeholders felt that MakCHS was insufficiently marketing itself and not directly engaging the private sector or Parliament. Stakeholders also identified the opportunity for MakCHS to embrace information technology in research, learning and training, and many also wanted MakCHS to start leadership and management training programmes in health systems. The need for MakCHS to be more vigorous in training to enhance professionalism and ethical conduct was also identified.</p> <p>Discussion</p> <p>As a constituent of a public university, MakCHS has relied on public funding, which has been inadequate to fulfill its mission. Broader networking, marketing to mobilize resources, and providing strong leadership and management support to inspire confidence among its current and potential stakeholders will be essential to MakCHS’ further growth. MakCHS’ relevance is hinged on generating research knowledge for solving the country’s contemporary health problems and starting relevant programs and embracing technologies. It should share new knowledge widely through publications and other forms of dissemination. Whether institutional leadership is best in the hands of academicians or professional managers is a debatable matter.</p> <p>Conclusions</p> <p>This study points towards the need for MakCHS and other African public universities to build a broad network of partnerships to strengthen their operations, relevance, and sustainability. Conducting stakeholder and sustainability analyses are instructive toward this end, and have provided information and perspectives on how to make long-range informed choices for success.</p
Low Energy 6-Dimensional N=2 Supersymmertric SU(6) Models on Orbifolds
We propose low energy 6-dimensional N=2 supersymmetric SU(6) models on
and , where the orbifold
model can be embedded on the boundary 4-brane. For the
zero modes, the 6-dimensional N=2 supersymmetry and the SU(6) gauge symmetry
are broken down to the 4-dimensional N=1 supersymmetry and the gauge symmetry by orbifold projections. In
order to cancel the anomalies involving at least one , we add extra
exotic particles. We also study the anomaly free conditions and present some
anomaly free models. The gauge coupling unification can be achieved at TeV if the compactification scale for the fifth dimension is
TeV. The proton decay problem can be avoided by putting the quarks and
leptons/neutrinos on different 3-branes. And we discuss how to break the
gauge symmetry, solve the
problem, and generate the mass hierarchy naturally by using the
geometry. The masses of exotic particles can be at the order of 1 TeV after the
gauge symmetry breaking. We also forbid the dimension-5 operators for the
neutrino masses by gauge symmetry, and the realistic left-handed
neutrino masses can be obtained via non-renormalizable terms.Comment: Latex, 33 pages, discussion and references adde
Composite Dirac Neutrinos
We present a mechanism that naturally produces light Dirac neutrinos. The
basic idea is that the right-handed neutrinos are composite. Any realistic
composite model must involve `hidden flavor' chiral symmetries. In general some
of these symmetries may survive confinement, and in particular, one of them
manifests itself at low energy as an exact symmetry. Dirac neutrinos are
therefore produced. The neutrinos are naturally light due to compositeness. In
general, sterile states are present in the model, some of them can naturally be
warm dark matter candidates.Comment: 12 pages; Sec. IIC updated; minor corrections; published versio
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