240 research outputs found
An Open Pouring Problem
We analyze a little riddle that has challenged mathematicians for half a century. Imagine three clubs catering to people with some niche interest. Everyone willing to join a club has done so and nobody new will pick up this eccentric hobby for the foreseeable future, thus the mutually exclusive clubs compete for a common constituency. Members are highly invested in their chosen club; only a targeted campaign plus prolonged personal persuasion can convince them to consider switching. Even then, they will never be enticed into a bigger group as they naturally pride themselves in avoiding the mainstream. Therefore each club occasionally starts a campaign against a larger competitor and sends its own members out on a recommendation program. Each will win one person over; the small club can thus effectively double its own numbers at the larger one’s expense. Is there always a risk for one club to wind up with zero members, forcing it out of business? If so, how many campaign cycles will this take?ISSN:1868-896
Near-term quantum-repeater experiments with nitrogen-vacancy centers: Overcoming the limitations of direct transmission
Quantum channels enable the implementation of communication tasks
inaccessible to their classical counterparts. The most famous example is the
distribution of secret key. However, in the absence of quantum repeaters, the
rate at which these tasks can be performed is dictated by the losses in the
quantum channel. In practice, channel losses have limited the reach of quantum
protocols to short distances. Quantum repeaters have the potential to
significantly increase the rates and reach beyond the limits of direct
transmission. However, no experimental implementation has overcome the direct
transmission threshold. Here, we propose three quantum repeater schemes and
assess their ability to generate secret key when implemented on a setup using
nitrogen-vacancy (NV) centers in diamond with near-term experimental
parameters. We find that one of these schemes - the so-called single-photon
scheme, requiring no quantum storage - has the ability to surpass the capacity
- the highest secret-key rate achievable with direct transmission - by a factor
of 7 for a distance of approximately 9.2 km with near-term parameters,
establishing it as a prime candidate for the first experimental realization of
a quantum repeater.Comment: 19+17 pages, 17 figures. v2: added "Discussion and future outlook"
section and expanded introduction, published versio
Profiling the Australian high performance and sports science workforce
Australia is viewed as leader in the field of sports science, with Australian sports scientists highly sought after and respected worldwide. However, despite the important contribution of sports scientists to the development of professional sport in Australia, we know little about these sport professionals who play an important role in the development and success of athletes, teams and sport organisations.This report provides a more formal understanding of the high performance and sports science workforce with the purpose of informing the policy development of Australia’s sport governing bodies and education providers to inform sport management practices that will enhance the support and development of current and future high performance managers and sports scientists. The data presented in this report provides valuable insight about the scope of the profession to enable further development of strategic plans for the industry
SENSE: Combining Mashup and HSM technology by semantic means to improve usability and performance
The amount of data stored and consumed on a daily basis as well as the complexity of the data structure have grown rapidly in past years [1]. Especially business companies try to reduce the rising expenses from storage infrastructure as well as from re-implementation of user interfaces to adapt to evolving tasks.
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On the possibility of radar echo detection of ultra-high energy cosmic ray- and neutrino-induced extensive air showers
We revisit and extend the analysis supporting a 60 year-old suggestion that
cosmic rays air showers resulting from primary particles with energies above
10^{18} eV should be straightforward to detect with radar ranging techniques,
where the radar echoes are produced by scattering from the column of ionized
air produced by the shower. The idea has remained curiously untested since it
was proposed, but if our analysis is correct, such techniques could provide a
significant alternative approach to air shower detection in a standalone array
with high duty cycle, and might provide highly complementary measurements of
air showers detected in existing and planned ground arrays such as the Fly's
Eye or the Auger Project. The method should be particularly sensitive to
showers that are transverse to and relatively distant from the detector, and is
thus effective in characterizing penetrating horizontal showers such as those
that might be induced by ultra-high energy neutrino primaries.Comment: 29 pages, 16 figures, uses aas2pp4.sty. Final version, to appear in
Astroparticle Physics. Contains new figs, better estimate of angular
precision possibl
Hyperlipidemia is a risk factor for osteonecrosis in children and young adults with acute lymphoblastic leukemia
TesisLa intoxicación con plomo es un problema de trascendental importancia para la salud pública por sus efectos en la calidad de vida de las personas, particularmente de los niños expuestos. La presente investigación fue de tipo descriptivo transversal y se realizó con la finalidad de determinar los niveles de plomo sanguíneo en los habitantes del Centro Poblado de Taca, durante los meses de junio y julio de 2013. Participaron del estudio 42 personas voluntarias: 32 varones y 10 mujeres, cuya media de edad fue de 33,23 años (rango: 21-72 años). Se tomaron muestras de sangre mediante venopunción previo consentimiento informado, utilizando tubos al vacío con anticoagulante, se mantuvieron bajo refrigeración a 8 °C, se trataron con mezcla sulfonítrica - ácido nítrico concentrado a ebullición lenta en un equipo de digestión y luego leídas en un espectrofotómetro de absorción atómica Thermo Scientific ¡CE 3300 a 217 nm. Se obtuvieron los siguientes resultados: todos los sujetos estudiados presentan algún grado de contaminación con plomo, encontrándose un nivel de plumbemia medio de 26,62 ug/dl y los niveles de plomo en sangre de varones y mujeres de 18 a 72 años de edad, encontrándose medias de 33,96 y 3,16 ug/dl, respectivamente, existiendo relación entre el género y plumbemia (p<0,05). El nivel de plomo en sangre de los habitantes del Centro Poblado de Taca, Distrito Canaria, Provincia de Víctor Fajardo, se incrementa en función del tiempo de residencia, por lo que existe relación entre estas dos variables (P<0,05)
Dendritic Cell-Based Immunotherapy for Prostate Cancer
Dendritic cells (DCs) are professional antigen-presenting cells (APCs), which display an extraordinary capacity to induce, sustain, and regulate T-cell responses providing the opportunity of DC-based cancer vaccination strategies. Thus, clinical trials enrolling prostate cancer patients were conducted, which were based on the administration of DCs loaded with tumor-associated antigens. These clinical trials revealed that DC-based immunotherapeutic strategies represent safe and feasible concepts for the induction of immunological and clinical responses in prostate cancer patients. In this context, the administration of the vaccine sipuleucel-T consisting of autologous peripheral blood mononuclear cells including APCs, which were pre-exposed in vitro to the fusion protein PA2024, resulted in a prolonged overall survival among patients with metastatic castration-resistent prostate cancer. In April 2010, sipuleucel-T was approved by the United States Food and Drug Administration for prostate cancer therapy
Initial PET Performance Evaluation of a Preclinical Insert for PET/MRI with Digital SiPM Technology
Hyperion-IID is a positron emission tomography (PET) insert which allows
simultaneous operation in a clinical magnetic resonance imaging (MRI) scanner.
To read out the scintillation light of the employed LYSO crystal arrays with a
pitch of 1 mm pitch and 12 mm in height, digital silicon photomultipliers (DPC
3200-22, Philips Digital Photon Counting) (DPC) are used. The basic PET
performance in terms of energy resolution, coincidence resolution time (CRT)
and sensitivity as a function of operating parameters, such as the operating
temperature, the applied overvoltage, activity and configuration parameters of
the DPCs, were evaluated on system level. The measured energy resolution did
not show a large dependency on the selected parameters and is in the range of
12.4-12.9% for low activities and degrades to ~13.6% at activities of ~100 MBq.
The CRT strongly depends on the selected trigger scheme (trig) of the DPCs. We
measured approximately 260 ps, 440 ps, 540 ps and 1300 ps for trig 1-4,
respectively. The trues sensitivity for a NEMA NU 4 mouse-sized scatter phantom
with a 70-mm-long tube of activity was dependent on the operating parameters
and was determined to be 0.4-1.4% at low activities. The random fraction stayed
below 5% at activities up to 100 MBq and the scatter fraction was evaluated as
~6% for an energy window of 411-561 keV and ~16% for 250-625 keV. Furthermore,
we performed imaging experiments using a mouse-sized hot-rod phantom and a
large rabbit-sized phantom. In 2D slices of the reconstructed mouse-sized
hot-rod phantom ({\O} = 28 mm), the rods were distinguishable from each other
down to a rod size of 0.8 mm. There was no benefit of the better CRT of trig 1
over trig 3, where in the larger rabbit-sized phantom ({\O} = 114 mm), we could
show a clear improvement of image quality using the time-of-flight information.Comment: Final journal version including the supplemntal data. The images in
the supplement were compressed to meet the arXiv file size limi
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