Differential Privacy and the Fat-Shattering Dimension of Linear Queries

In this paper, we consider the task of answering linear queries under the constraint of differential privacy. This is a general and well-studied class of queries that captures other commonly studied classes, including predicate queries and histogram queries. We show that the accuracy to which a set of linear queries can be answered is closely related to its fat-shattering dimension, a property that characterizes the learnability of real-valued functions in the agnostic-learning setting.Comment: Appears in APPROX 201

Molecular diversity within clonal complex 22 methicillin-resistant Staphylococcus aureus encoding Panton–Valentine leukocidin in England and Wales

AbstractPanton–Valentine leukocidin (PVL)-positive methicillin-resistant Staphylococcus aureus (MRSA) that are multi-locus sequence type clonal complex 22 (CC22) comprise a significant public health problem in the UK. In the present study we sought to determine the genetic diversity, and the respective patient demographics, among 47 PVL-MRSA with a CC22 pulsotype that occurred sporadically or in clusters in community and healthcare settings in eight of nine geographic regions in England and Wales between January 2005 and September 2007. Patient demographics and disease presentations were typical for PVL-S. aureus infections (mostly skin and soft tissue infections in individuals <40 years old); one patient with community-acquired pneumonia died. Although the isolates were closely genotypically related by spa typing and pulsed field gel electrophoresis, at least two variant groups were suggested. PCR detections demonstrated that the majority of the CC22 PVL-MRSA identified (n = 42; 89%) harboured SCCmecIVc, three had SCCmecIVd, one had SCCmecIV but was non-subtypeable, and one isolate harboured SCCmecV. At least three different PVL-encoding phages were detected: ΦPVL, Φ108PVL and an unidentified icosahedral phage. Agar dilution MIC determinations showed that the CC22 PVL-MRSA identified were typically resistant to gentamicin and trimethoprim (43 of 47 isolates) and ciprofloxacin resistance was also noted in six isolates. In conclusion, the CC22 PVL-MRSA tested were geographically disseminated but highly genetically related. The observed variances in acquired elements (most notably SCCmec and PVL-encoding phages) suggested that CC22 PVL-MRSA in England and Wales have evolved on multiple occasions

GlycoGrip: Cell Surface-Inspired Universal Sensor for Betacoronaviruses

Inspired by the role of cell-surface glycoproteins as coreceptors for pathogens, we report the development of GlycoGrip: a glycopolymer-based lateral flow assay for detecting SARS-CoV-2 and its variants. GlycoGrip utilizes glycopolymers for primary capture and antispike antibodies labeled with gold nanoparticles for signal-generating detection. A lock-step integration between experiment and computation has enabled efficient optimization of GlycoGrip test strips which can selectively, sensitively, and rapidly detect SARS-CoV-2 and its variants in biofluids. Employing the power of the glycocalyx in a diagnostic assay has distinct advantages over conventional immunoassays as glycopolymers can bind to antigens in a multivalent capacity and are highly adaptable for mutated strains. As new variants of SARS-CoV-2 are identified, GlycoGrip will serve as a highly reconfigurable biosensor for their detection. Additionally, via extensive ensemble-based docking simulations which incorporate protein and glycan motion, we have elucidated important clues as to how heparan sulfate and other glycocalyx components may bind the spike glycoprotein during SARS-CoV-2 host-cell infection. GlycoGrip is a promising and generalizable alternative to costly, labor-intensive RT-PCR, and we envision it will be broadly useful, including for rural or low-income populations that are historically undertested and under-reported in infection statistics

Calculation of the age of the first infection for skin sores and scabies in five remote communities in northern Australia

Prevalence of skin sores and scabies in remote Australian Aboriginal communities remains unacceptably high, with Group A Streptococcus (GAS) the dominant pathogen. We aim to better understand the drivers of GAS transmission using mathematical models. To estimate the force of infection, we quantified the age of first skin sores and scabies infection by pooling historical data from three studies conducted across five remote Aboriginal communities for children born between 2001 and 2005. We estimated the age of the first infection using the Kaplan–Meier estimator; parametric exponential mixture model; and Cox proportional hazards. For skin sores, the mean age of the first infection was approximately 10 months and the median was 7 months, with some heterogeneity in median observed by the community. For scabies, the mean age of the first infection was approximately 9 months and the median was 8 months, with significant heterogeneity by the community and an enhanced risk for children born between October and December. The young age of the first infection with skin sores and scabies reflects the high disease burden in these communities.We acknowledge the Lowitja Institute and the Cooperative Research Centre for Aboriginal Health who originally funded and lent significant support to the EAHSP. M. J. Lydeamore is funded by an Australian Postgraduate Research Training Program Scholarship; This work is supported by an NHMRC Project Grant titled ‘Optimising intervention strategies to reduce the burden of Group A Streptococcus in Aboriginal Communities’ (GNT1098319). We thank the NHMRC Centre for Research Excellence in Infectious Diseases Modelling to Inform Public Health Policy (GNT1078068). J. McVernon is supported by an NHMRC Principal Research Fellowship (GNT1117140). S. Tong is supported by an NHMRC Career Development Fellowship (GNT1145033)

Measurement of the residual energy of muons in the Gran Sasso underground Laboratories

The MACRO detector was located in the Hall B of the Gran Sasso underground Laboratories under an average rock overburden of 3700 hg/cm^2. A transition radiation detector composed of three identical modules, covering a total horizontal area of 36 m^2, was installed inside the empty upper part of the detector in order to measure the residual energy of muons. This paper presents the measurement of the residual energy of single and double muons crossing the apparatus. Our data show that double muons are more energetic than single ones. This measurement is performed over a standard rock depth range from 3000 to 6500 hg/cm^2.Comment: 28 pages, 9 figure

Muon Energy Estimate Through Multiple Scattering with the Macro Detector

Muon energy measurement represents an important issue for any experiment addressing neutrino induced upgoing muon studies. Since the neutrino oscillation probability depends on the neutrino energy, a measurement of the muon energy adds an important piece of information concerning the neutrino system. We show in this paper how the MACRO limited streamer tube system can be operated in drift mode by using the TDC's included in the QTPs, an electronics designed for magnetic monopole search. An improvement of the space resolution is obtained, through an analysis of the multiple scattering of muon tracks as they pass through our detector. This information can be used further to obtain an estimate of the energy of muons crossing the detector. Here we present the results of two dedicated tests, performed at CERN PS-T9 and SPS-X7 beam lines, to provide a full check of the electronics and to exploit the feasibility of such a multiple scattering analysis. We show that by using a neural network approach, we are able to reconstruct the muon energy for $E_\mu<$40 GeV. The test beam data provide an absolute energy calibration, which allows us to apply this method to MACRO data.Comment: 25 pages, 11 figures, Submitted to Nucl. Instr. & Meth.