1,500 research outputs found
A construction of bent functions from plateaued functions
In this presentation, a technique for constructing bent functions from plateaued functions is introduced and analysed. This generalizes earlier techniques for constructing bent from near-bent functions. Using this construction, we obtain a big variety of inequivalent bent functions, some weakly regular and some non-weakly regular. Classes of bent function with some additional properties that enable the construction of strongly regular graphs are constructed, and explicit expressions for bent functions with maximal degree are presented
Fixed-Budget Differentially Private Best Arm Identification
We study best arm identification (BAI) in linear bandits in the fixed-budget
regime under differential privacy constraints, when the arm rewards are
supported on the unit interval. Given a finite budget and a privacy
parameter , the goal is to minimise the error probability in
finding the arm with the largest mean after sampling rounds, subject to the
constraint that the policy of the decision maker satisfies a certain {\em
-differential privacy} (-DP) constraint. We construct
a policy satisfying the -DP constraint (called {\sc DP-BAI}) by
proposing the principle of {\em maximum absolute determinants}, and derive an
upper bound on its error probability. Furthermore, we derive a minimax lower
bound on the error probability, and demonstrate that the lower and the upper
bounds decay exponentially in , with exponents in the two bounds matching
order-wise in (a) the sub-optimality gaps of the arms, (b) , and
(c) the problem complexity that is expressible as the sum of two terms, one
characterising the complexity of standard fixed-budget BAI (without privacy
constraints), and the other accounting for the -DP constraint.
Additionally, we present some auxiliary results that contribute to the
derivation of the lower bound on the error probability. These results, we
posit, may be of independent interest and could prove instrumental in proving
lower bounds on error probabilities in several other bandit problems. Whereas
prior works provide results for BAI in the fixed-budget regime without privacy
constraints or in the fixed-confidence regime with privacy constraints, our
work fills the gap in the literature by providing the results for BAI in the
fixed-budget regime under the -DP constraint.Comment: Accepted to ICLR 202
Immunopathology of Virus-Induced Anterior Uveitis
Herpes simplex virus, varicella zoster virus, human cytomegalovirus, and rubella virus are the most common causes of virus-induced anterior uveitis. They can present in a variety of entities not only with typical but also overlapping clinical ch
Torsion and accelerating expansion of the universe in quadratic gravitation
Several exact cosmological solutions of a metric-affine theory of gravity
with two torsion functions are presented. These solutions give a essentially
different explanation from the one in most of previous works to the cause of
the accelerating cosmological expansion and the origin of the torsion of the
spacetime. These solutions can be divided into two classes. The solutions in
the first class define the critical points of a dynamical system representing
an asymptotically stable de Sitter spacetime. The solutions in the second class
have exact analytic expressions which have never been found in the literature.
The acceleration equation of the universe in general relativity is only a
special case of them. These solutions indicate that even in vacuum the
spacetime can be endowed with torsion, which means that the torsion of the
spacetime has an intrinsic nature and a geometric origin. In these solutions
the acceleration of the cosmological expansion is due to either the scalar
torsion or the pseudoscalar torsion function. Neither a cosmological constant
nor dark energy is needed. It is the torsion of the spacetime that causes the
accelerating expansion of the universe in vacuum. All the effects of the
inflation, the acceleration and the phase transformation from deceleration to
acceleration can be explained by these solutions. Furthermore, the energy and
pressure of the matter without spin can produce the torsion of the spacetime
and make the expansion of the universe decelerate as well as accelerate.Comment: 20 pages. arXiv admin note: text overlap with gr-qc/0604006,
arXiv:1110.344
Feasibility and usability of a regional hub model for colorectal cancer services during the COVID-19 pandemic
The outbreak of the COVID-19 pandemic produced unprecedented challenges, at a global level, in the provision of cancer care. With the ongoing need in the delivery of life-saving cancer treatment, the surgical management of patients with colorectal cancer required prompt significant transformation. The aim of this retrospective study is to report the outcome of a bespoke regional Cancer Hub model in the delivery of elective and essential colorectal cancer surgery, at the height of the first wave of the COVID-19 pandemic. 168 patients underwent colorectal cancer surgery from April 1st to June 30th of 2020. Approximately 75% of patients operated upon underwent colonic resection, of which 47% were left-sided, 34% right-sided and 12% beyond total mesorectal excision surgeries. Around 79% of all resectional surgeries were performed via laparotomy, and the remainder 21%, robotically or laparoscopically. Thirty-day complication rate, for Clavien-Dindo IIIA and above, was 4.2%, and 30-day mortality rate was 0.6%. Re-admission rate, within 30 days post-discharge, was 1.8%, however, no patient developed COVID-19 specific complications post-operatively and up to 28 days post-discharge. The established Cancer Hub offered elective surgical care for patients with colorectal cancer in a centralised, timely and efficient manner, with acceptable post-operative outcomes and no increased risk of contracting COVID-19 during their inpatient stay. We offer a practical model of care that can be used when elective surgery "hubs" for streamlined delivery of elective care needs to be established in an expeditious fashion, either due to the COVID-19 pandemic or any other future pandemics
On Quantum Effects in Soft Leptogenesis
It has been recently shown that quantum Boltzman equations may be relevant
for leptogenesis. Quantum effects, which lead to a time-dependent CP asymmetry,
have been shown to be particularly important for resonant leptogenesis when the
asymmetry is generated by the decay of two nearly degenerate states. In this
work we investigate the impact of the use of quantum Boltzman equations in the
framework ``soft leptogenesis'' in which supersymmetry soft-breaking terms give
a small mass splitting between the CP-even and CP-odd right-handed sneutrino
states of a single generation and provide the CP-violating phase to generate
the lepton asymmetry.Comment: 15 pages, 4 figures. Replacement to match published versio
Wireless body sensor design for intra-vaginal temperature monitoring
Sensor nodes are small devices able to collect and retrieve
sensorial data. The use of these sensors for medical purposes
offers valuable contributions to improve patients’ healthcare, both
for diagnosis and therapeutics monitoring. An important and
common parameter used on healthcare diagnosis is the body
temperature. It is monitored on several matters related with
gynecological and obstetrics issues but, usually it is measure at
the skin surface. Then, this paper proposes the design concepts of
a new intra-body sensor for long-term intra-vaginal temperature
collection. The embedded IEEE 802.15.4 communication module
allows the integration of this sensor in wireless sensor networks
for remote data access and monitoring. It is presented the sensor
architecture, the construction of the corresponding testbed, and its
performance evaluation. This sensor may be used on several
applications, including fertile and ovulation period detection, and
preterm labor prevention
Flavoured soft leptogenesis and natural values of the B term
We revisit flavour effects in soft leptogenesis relaxing the assumption of
universality for the soft supersymmetry breaking terms. We find that with
respect to the case in which the heavy sneutrinos decay with equal rates and
equal CP asymmetries for all lepton flavours, hierarchical flavour
configurations can enhance the efficiency by more than two orders of magnitude.
This translates in more than three order of magnitude with respect to the
one-flavour approximation. We verify that lepton flavour equilibration effects
related to off-diagonal soft slepton masses are ineffective for damping these
large enhancements. We show that soft leptogenesis can be successful for
unusual values of the relevant parameters, allowing for and for values of the washout parameter up to .Comment: 23 pages, 5 figures postscript, Minor changes to match the published
version in JHE
Two novel human cytomegalovirus NK cell evasion functions target MICA for lysosomal degradation
NKG2D plays a major role in controlling immune responses through the regulation of natural killer (NK) cells, αβ and γδ T-cell function. This activating receptor recognizes eight distinct ligands (the MHC Class I polypeptide-related sequences (MIC) A andB, and UL16-binding proteins (ULBP)1–6) induced by cellular stress to promote recognition cells perturbed by malignant transformation or microbial infection. Studies into human cytomegalovirus (HCMV) have aided both the identification and characterization of NKG2D ligands (NKG2DLs). HCMV immediate early (IE) gene up regulates NKGDLs, and we now describe the differential activation of ULBP2 and MICA/B by IE1 and IE2 respectively. Despite activation by IE functions, HCMV effectively suppressed cell surface expression of NKGDLs through both the early and late phases of infection. The immune evasion functions UL16, UL142, and microRNA(miR)-UL112 are known to target NKG2DLs. While infection with a UL16 deletion mutant caused the expected increase in MICB and ULBP2 cell surface expression, deletion of UL142 did not have a similar impact on its target, MICA. We therefore performed a systematic screen of the viral genome to search of addition functions that targeted MICA. US18 and US20 were identified as novel NK cell evasion functions capable of acting independently to promote MICA degradation by lysosomal degradation. The most dramatic effect on MICA expression was achieved when US18 and US20 acted in concert. US18 and US20 are the first members of the US12 gene family to have been assigned a function. The US12 family has 10 members encoded sequentially through US12–US21; a genetic arrangement, which is suggestive of an ‘accordion’ expansion of an ancestral gene in response to a selective pressure. This expansion must have be an ancient event as the whole family is conserved across simian cytomegaloviruses from old world monkeys. The evolutionary benefit bestowed by the combinatorial effect of US18 and US20 on MICA may have contributed to sustaining the US12 gene family
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