The effect of GPS refresh rate on measuring police patrol in micro-places

© 2021, The Author(s). With the increasing prevalence of police interventions implemented in micro hot-spots of crime, the accuracy with which officer foot patrols can be measured is increasingly important for the robust evaluation of such strategies. However, it is currently unknown how the accuracy of GPS traces impact upon our understanding of where officers are at a given time and how this varies for different GPS refresh rates. Most existing studies that use GPS data fail to acknowledge this. This study uses GPS data from police officer radios and ground truth data to estimate how accurate GPS data are for different GPS refresh rates. The similarity of the assumed paths are quantitatively evaluated and the analysis shows that different refresh rates lead to diverging estimations of where officers have patrolled. These results have significant implications for the measurement of police patrols in micro-places and evaluations of micro-place based interventions

Rational Design of Pore Size and Functionality in a Series of Isoreticular Zwitterionic Metal-Organic Frameworks

The isoreticular expansion and functionalization of charged-polarized porosity has been systematically explored by the rational design of 11 isostructural zwitterionic metal-organic frameworks (ZW-MOFs). This extended series of general structural composition {[M3F(L1)3(L2)1.5]·guests}n was prepared by employing the solvothermal reaction of Co and Ni tetrafluoroborates with a binary ligand system composed of zwitterionic pyridinium derivatives and traditional functionalized ditopic carboxylate auxiliary ligands (HL1·Cl = 1-(4-carboxyphenyl)-4,4′-bipyridinium chloride, Hcpb·Cl; or 1-(4-carboxyphenyl-3-hydroxyphenyl)-4,4′-bipyridinium chloride, Hchpb·Cl; and H2L2 = benzene-1,4-dicarboxylic acid, H2bdc; 2-aminobenzene-1,4-dicarboxylic acid, H2abdc; 2,5-dihydroxy-1,4-benzenedicarboxylic acid, H2dhbdc; biphenyl-4,4′-dicarboxylic acid, H2bpdc; or stilbene-4,4′-dicarboxylic acid, H2sdc). Single-crystal structure analyses revealed cubic crystal symmetry (I-43m, a = 31-36 Å) with a 3D pore system of significant void space (73-81%). The pore system features three types of pores being systematically tunable in size ranging from 17.4 to 18.8 Å (pore I), 8.2 to 12.8 Å (pore II), and 4.8 to 10.4 Å (pore III) by the choice of auxiliary ligands. All members of this series have noninterpenetrating structures and exhibit robust architectures, as evidenced by their permanent porosity and high thermal stability (up to 300 °C). The structural integrity and specific surface areas could be systematically optimized using supercritical CO2 exchange methods for framework activation resulting in BET surface areas ranging from 1250 to 2250 m2/g. Most interestingly, as a structural landmark, we found the pore surfaces lined with charge gradients employed by the pyridinium ligands. This key feature results in significant adsorption of carbon dioxide and methane which is attributed to polarization effects. With this contribution we pioneer the reticulation of pyridinium building blocks into extended zwitterionic networks in which specific properties can be targeted

Data and evidence challenges facing place-based policing

PURPOSE: The purpose of this paper is to use an evaluation of a micro-place-based hot-spot policing implementation to highlight the potential issues raised by data quality standards in the recording and measurement of crime data and police officer movements. DESIGN/METHODOLOGY/APPROACH: The study focusses on an area of London (UK) which used a predictive algorithm to designate micro-place patrol zones for each police shift over a two-month period. Police officer movements are measured using GPS data from officer-worn radios. Descriptive statistics regarding the crime data commonly used to evaluate this type of implementation are presented, and simple analyses are presented to examine the effects of officer patrol duration (dosage) on crime in micro-place hot-spots. FINDINGS: The results suggest that patrols of 10-20 minutes in a given police shift have a significant impact on reducing crime; however, patrols of less than about 10 minutes and more than about 20 minutes are ineffective at deterring crime. RESEARCH LIMITATIONS/IMPLICATIONS: Due to the sparseness of officer GPS data, their paths have to be interpolated which could introduce error to the estimated patrol dosages. Similarly, errors and uncertainty in recorded crime data could have substantial impact on the designation of micro-place interventions and evaluations of their effectiveness. ORIGINALITY/VALUE: This study is one of the first to use officer GPS data to estimate patrol dosage and places particular emphasis on the issue of data quality when evaluating micro-place interventions

Radiative lifetimes and cooling functions for astrophysically important molecules

© 2016 IOP Publishing Ltd. Extensive line lists generated as part of the ExoMol project are used to compute lifetimes for individual rotational, rovibrational and rovibronic excited states, and temperature-dependent cooling functions by summing over all dipole-allowed transitions for the states concerned. Results are presented for SiO, CaH, AlO, ScH, H2O and methane. The results for CH4 are particularly unusual with four excited states with no dipole-allowed decay route and several others, where these decays lead to exceptionally long lifetimes. These lifetime data should be useful in models of masers and estimates of critical densities, and can provide a link with laboratory measurements. Cooling functions are important in stellar and planet formation

Demonstration of nanoimprinted hyperlens array for high-throughput sub-diffraction imaging

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Estimating Hydraulic Properties of Alluvial Sand Aquifer in Motloutse River course, Eastern Botswana

A single layered alluvial aquifer in Botswana along the Motloutse River catchment was studied to estimate its hydraulic properties. Ground Penetrating Radar Survey (GPR) was used to determine the thickness and porosity of the aquifer. Specific yield of the aquifer was determined in the laboratory. The hydraulic conductivity of the riverbed sediments were estimated using the Alyamani-Sen empirical formula and the hydraulic conductivity of the river bank sediment was measured using the slug test. Geologically, the area is consists of alluvial deposits overlying granite, which is the bed rock of the area. The geophysical survey, GPR, provided information on the range of the thickness of the alluvium (9 – 12m) and also the porosity of the sediments (40%). The laboratory test resulted in an average specific yield of 13.68% for the riverbed sediments and 8.84% for the river bank sediments. A slug test performed in the riverbank yielded estimates of hydraulic conductivity of 26.43m/day. An average hydraulic conductivity value of 160m/day for the riverbed sediments was determined using the Alyamani-Sen formula. This difference in the hydraulic properties of the riverbed and the riverbank sediments is likely to be a result of sediment heterogeneity as more fine grained sediments is found together with sand in the riverbank sediments. These combined hydraulic properties estimation using empirical formulas, geophysical survey, laboratory tests, and the slug test highly improved the understanding of the hydrologic properties of the single layered alluvial aquifer system in the Motloutse River catchment. In the same area, groundwater resource modelling can be done using these aquifer parameters to determine the groundwater potential of the aquifer

20 K superconductivity in heavily electron doped surface layer of FeSe bulk crystal

A superconducting transition temperature Tc as high as 100 K was recently discovered in 1 monolayer (1ML) FeSe grown on SrTiO3 (STO). The discovery immediately ignited efforts to identify the mechanism for the dramatically enhanced Tc from its bulk value of 7 K. Currently, there are two main views on the origin of the enhanced Tc; in the first view, the enhancement comes from an interfacial effect while in the other it is from excess electrons with strong correlation strength. The issue is controversial and there are evidences that support each view. Finding the origin of the Tc enhancement could be the key to achieving even higher Tc and to identifying the microscopic mechanism for the superconductivity in iron-based materials. Here, we report the observation of 20 K superconductivity in the electron doped surface layer of FeSe. The electronic state of the surface layer possesses all the key spectroscopic aspects of the 1ML FeSe on STO. Without any interface effect, the surface layer state is found to have a moderate Tc of 20 K with a smaller gap opening of 4 meV. Our results clearly show that excess electrons with strong correlation strength alone cannot induce the maximum Tc, which in turn strongly suggests need for an interfacial effect to reach the enhanced Tc found in 1ML FeSe/STO.Comment: 5 pages, 4 figure

Successive spin-flop transitions of a Neel-type antiferromagnet Li2MnO3 single crystal with a honeycomb lattice

We have carried out high magnetic field studies of single-crystalline Li2MnO3, a honeycomb lattice antiferromagnet. Its magnetic phase diagram was mapped out using magnetization measurements at applied fields up to 35 T. Our results show that it undergoes two successive meta-magnetic transitions around 9 T fields applied perpendicular to the ab plane (along the c* axis). These phase transitions are completely absent in the magnetization measured with the field applied along the ab plane. In order to understand this magnetic phase diagram, we developed a mean-field model starting from the correct Neel-type magnetic structure, consistent with our single crystal neutron diffraction data at zero field. Our model calculations succeeded in explaining the two meta-magnetic transitions that arise when Li2MnO3 enters two different spin-flop phases from the zero field Neel phase.open1187Nsciescopu