The concentration of police resources in stable crime hotspots has proven effective in reducing crime, but the extent to which police can disrupt dynamically changing crime hotspots is unknown. ...Police must be able to anticipate the future location of dynamic hotspots to disrupt them. Here we report results of two randomized controlled trials of near real-time epidemic-type aftershock sequence (ETAS) crime forecasting, one trial within three divisions of the Los Angeles Police Department and the other trial within two divisions of the Kent Police Department (United Kingdom). We investigate the extent to which (i) ETAS models of short-term crime risk outperform existing best practice of hotspot maps produced by dedicated crime analysts, (ii) police officers in the field can dynamically patrol predicted hotspots given limited resources, and (iii) crime can be reduced by predictive policing algorithms under realistic law enforcement resource constraints. While previous hotspot policing experiments fix treatment and control hotspots throughout the experimental period, we use a novel experimental design to allow treatment and control hotspots to change dynamically over the course of the experiment. Our results show that ETAS models predict 1.4–2.2 times as much crime compared to a dedicated crime analyst using existing criminal intelligence and hotspot mapping practice. Police patrols using ETAS forecasts led to an average 7.4% reduction in crime volume as a function of patrol time, whereas patrols based upon analyst predictions showed no significant effect. Dynamic police patrol in response to ETAS crime forecasts can disrupt opportunities for crime and lead to real crime reductions.
Longer-term (i.e., 20–40 years) tropospheric ozone (O3) time series obtained from surface and ozonesonde observations have been analyzed to assess possible changes with time through 2010. The time ...series have been selected to reflect relatively broad geographic regions and where possible minimize local scale influences, generally avoiding sites close to larger urban areas. Several approaches have been used to describe the changes with time, including application of a time series model, running 15-year trends, and changes in the distribution by month in the O3 mixing ratio. Changes have been investigated utilizing monthly averages, as well as exposure metrics that focus on specific parts of the distribution of hourly average concentrations (e.g., low-, mid-, and high-level concentration ranges). Many of the longer time series (∼30 years) in mid-latitudes of the Northern Hemisphere, including those in Japan, show a pattern of significant increase in the earlier portion of the record, with a flattening over the last 10–15 years. It is uncertain if the flattening of the O3 change over Japan reflects the impact of O3 transported from continental East Asia in light of reported O3 increases in China. In the Canadian Arctic, declines from the beginning of the ozonesonde record in 1980 have mostly rebounded with little overall change over the period of record. The limited data in the tropical Pacific suggest very little change over the entire record. In the southern hemisphere subtropics and mid-latitudes, the significant increase observed in the early part of the record has leveled off in the most recent decade. At the South Pole, a decline observed during the first half of the 35-year record has reversed, and O3 has recovered to levels similar to the beginning of the record. Our understanding of the causes of the longer-term changes is limited, although it appears that in the mid-latitudes of the northern hemisphere, controls on O3 precursors have likely been a factor in the leveling off or decline from earlier O3 increases.
► O3 at mid-latitudes of the N.H. is flat or declining in the last 10–15 years. ► O3 in S.H. subtropics and mid-latitudes increased earlier but has leveled off. ► 15-year moving trends reveal changes in both high and low O3 concentrations. ► Precursor (NOx) reductions in Europe and N.A. likely contribute to O3 decline.
Abstract
The gas content of the complete compilation of Local Group dwarf galaxies (119 within 2 Mpc) is presented using H
i
survey data. Within the virial radius of the Milky Way (224 kpc here), 53 ...of 55 dwarf galaxies are devoid of gas to limits of
M
H
i
< 10
4
M
⊙
. Within the virial radius of M31 (266 kpc), 27 of 30 dwarf galaxies are devoid of gas (with limits typically <10
5
M
⊙
). Beyond the virial radii of the Milky Way and M31, the majority of the dwarf galaxies have detected H
i
gas and H
i
masses higher than the limits. When the relationship between gas content and distance is investigated using a Local Group virial radius, more of the nondetected dwarf galaxies are within this radius (85 ± 1 of the 93 nondetected dwarf galaxies) than within the virial radii of the Milky Way and M31. Using the Gaia proper-motion measurements available for 38 dwarf galaxies, the minimum gas density required to completely strip them of gas is calculated. Halo densities between 10
−5
and 5 × 10
−4
cm
−3
are typically required for instantaneous stripping at perigalacticon. When compared to halo density with radius expectations from simulations and observations, 80% of the dwarf galaxies with proper motions are consistent with being stripped by ram pressure at Milky Way pericenter. The results suggest that a diffuse gaseous galactic halo medium is important in quenching dwarf galaxies, and that a Local Group medium also potentially plays a role.
Peripheral artery disease (PAD) is a common cardiovascular disorder that is frequently underdiagnosed, which can lead to poorer outcomes due to lower rates of medical optimization. We aimed to ...develop an automated tool to identify undiagnosed PAD and evaluate physician acceptance of a dashboard representation of risk assessment. Data were derived from electronic health records (EHR). We developed and compared traditional risk score models to novel machine learning models. For usability testing, primary and specialty care physicians were recruited and interviewed until thematic saturation. Data from 3168 patients with PAD and 16,863 controls were utilized. Results showed a deep learning model that utilized time engineered features outperformed random forest and traditional logistic regression models (average AUCs 0.96, 0.91 and 0.81, respectively), P < 0.0001. Of interviewed physicians, 75% were receptive to an EHR-based automated PAD model. Feedback emphasized workflow optimization, including integrating risk assessments directly into the EHR, using dashboard designs that minimize clicks, and providing risk assessments for clinically complex patients. In conclusion, we demonstrate that EHR-based machine learning models can accurately detect risk of PAD and that physicians are receptive to automated risk detection for PAD. Future research aims to prospectively validate model performance and impact on patient outcomes.
The rearing period has a key influence on the later performance of cattle, affecting future fertility and longevity. Producers usually aim to breed replacement heifers by 15 months to calve at 24 ...months. An age at first calving (AFC) close to 2 years (23 to 25 months) is optimum for economic performance as it minimises the non-productive period and maintains a seasonal calving pattern. This is rarely achieved in either dairy or beef herds, with average AFC for dairy herds usually between 26 and 30 months. Maintaining a low AFC requires good heifer management with adequate growth to ensure an appropriate BW and frame size at calving. Puberty should occur at least 6 weeks before the target breeding age to enable animals to undergo oestrous cycles before mating. Cattle reach puberty at a fairly consistent, but breed-dependent, proportion of mature BW. Heifer fertility is a critical component of AFC. In US Holsteins the conception rate peaked at 57% at 15 to 16 months, declining in older heifers. Wide variations in growth rates on the same farm often lead to some animals having delayed first breeding and/or conception. Oestrous synchronisation regimes and sexed semen can both be used but unless heifers have been previously well-managed the success rates may be unacceptably low. Altering the nutritional input above or below those needed for maintenance at any stage from birth to first calving clearly alters the average daily gain (ADG) in weight. In general an ADG of around 0.75 kg/day seems optimal for dairy heifers, with lower rates delaying puberty and AFC. There is some scope to vary ADG at different ages providing animals reach an adequate size by calving. Major periods of nutritional deficiency and/or severe calfhood disease will, however, compromise development with long-term adverse consequences. Infectious disease can also cause pregnancy loss/abortion. First lactation milk yield may be slightly lower in younger calving cows but lifetime production is higher as such animals usually have good fertility and survive longer. There is now extensive evidence that as long as the AFC is >23 months then future performance is not adversely influenced. On the other hand, delayed first calving >30 months is associated with poor survival. Underfeeding of young heifers reduces their milk production potential and is a greater problem than overfeeding. Farmers are more likely to meet the optimum AFC target of 23 to 25 months if they monitor growth rates and adjust feed accordingly.
Large-scale soil application of biochar may enhance soil fertility, increasing crop production for the growing human population, while also sequestering atmospheric carbon. But reaching these ...beneficial outcomes requires an understanding of the relationships among biochar’s structure, stability, and contribution to soil fertility. Using quantitative 13C nuclear magnetic resonance (NMR) spectroscopy, we show that Terra Preta soils (fertile anthropogenic dark earths in Amazonia that were enriched with char >800 years ago) consist predominantly of char residues composed of ∼6 fused aromatic rings substituted by COO– groups that significantly increase the soils’ cation-exchange capacity and thus the retention of plant nutrients. We also show that highly productive, grassland-derived soils in the U.S. (Mollisols) contain char (generated by presettlement fires) that is structurally comparable to char in the Terra Preta soils and much more abundant than previously thought (∼40–50% of organic C). Our findings indicate that these oxidized char residues represent a particularly stable, abundant, and fertility-enhancing form of soil organic matter.
Neuropathology of Cognitively Normal Elderly KNOPMAN, D S; PARISI, J E; SALVIATI, A ...
Journal of neuropathology and experimental neurology,
2003-November, Letnik:
62, Številka:
11
Journal Article
Recenzirano
Despite general agreement about the boundaries of Alzheimer disease (AD), establishing a maximum limit for Alzheimer-type pathology in cognitively intact individuals might aid in defining more ...precisely the point at which Alzheimer pathology becomes clinically relevant. In this study, we examined the neuropathological changes in the brains of 39 longitudinally followed, cognitively normal elderly individuals (24 women, 15 men; age range 74–95, median 85 years). Neuropathological changes of the Alzheimer type were quantified by determining neurofibrillary tangle (NFT) staging by the method of Braak and Braak and by quantification of the abundance of diffuse, cored, and neuritic plaque burden using the scheme developed by the Consortium to Establish a Registry for Alzheimer Disease (CERAD). Vascular, Lewy body, and argyrophilic grain pathology were also assessed. We found 34 subjects (87%) with a Braak stage <IV; 32 subjects (82%) with less than moderate numbers of cored plaques and 37 subjects (95%) with less than moderate numbers of tau-positive neuritic plaques. Many subjects had moderate or frequent diffuse plaques (n = 19, 49%). By the National Institute on Aging-Reagan Institute (NIA-RI) criteria, none of our cases met criteria for high “likelihood” of AD. Four met NIA-RI criteria for intermediate “likelihood.” Seven cases met CERAD criteria for possible AD. Nineteen met Khachaturian criteria for AD. Only 1 subject had neocortical Lewy bodies. Small, old infarcts were common, but no subjects had more than 2 of these and none had a single large infarction. Thus, the majority of individuals who are cognitively normal near the time of their death have minimal amounts of tau-positive neuritic pathology (Braak stage <IV and neuritic plaques <6 per ×100 field in the most affected neocortical region). The few subjects with more severe AD pathology can be expected based on incidence rates of AD in the very elderly.
PDF
