Despite the recent flurry of interest in various aspects of ancient urbanism, we still know little about how much traffic flowed in and out of ancient cities, in part because of problems with using ...commodities as proxies for trade. This article investigates another approach, which is to estimate these flows from the built environment, concentrating on transport infrastructure such as city gates. To do this, I begin by discussing a new model for how we would expect this kind of infrastructure to expand with population, before investigating the relationship between the populations of sites and the total numbers and widths of city gates, focusing on the Greek and Roman world. The results suggest that there is indeed a systematic relationship between the estimated populations of cities and transport infrastructure, which is entirely consistent with broader theoretical and empirical expectations. This gives us a new way of exploring the connectivity and integration of ancient cities, contributing to a growing body of general theory about how settlements operate across space and time.
The design of power magnetic components for operation at high frequency (HF, 3-30 MHz) has been hindered by a lack of magnetic material performance data and by the limited design theory in that ...frequency range. To address these deficiencies, we have measured and present core loss data for a variety of commercially available magnetic materials in the HF range. In addition, we extend the theory of performance factor for appropriate use in the HF design. Since magnetic materials suitable for HF applications tend to have low permeability, we also consider the impact of low permeability on design. We conclude that, with appropriate material selection and design, increased frequencies can continue to yield improved power density well into the HF regime.
Emergence and spread of antibiotic resistance has become a global health threat and is often linked with overuse and misuse of clinical and veterinary chemotherapeutic agents. Modern industrial-scale ...animal feeding operations rely extensively on veterinary pharmaceuticals, including antibiotics, to augment animal growth. Following excretion, antibiotics are transported through the environment via runoff, leaching, and land application of manure; however, airborne transport from feed yards has not been characterized.
The goal of this study was to determine the extent to which antibiotics, antibiotic resistance genes (ARG), and ruminant-associated microbes are aerially dispersed via particulate matter (PM) derived from large-scale beef cattle feed yards.
PM was collected downwind and upwind of 10 beef cattle feed yards. After extraction from PM, five veterinary antibiotics were quantified via high-performance liquid chromatography with tandem mass spectrometry, ARG were quantified via targeted quantitative polymerase chain reaction, and microbial community diversity was analyzed via 16S rRNA amplification and sequencing.
Airborne PM derived from feed yards facilitated dispersal of several veterinary antibiotics, as well as microbial communities containing ARG. Concentrations of several antibiotics in airborne PM immediately downwind of feed yards ranged from 0.5 to 4.6 μg/g of PM. Microbial communities of PM collected downwind of feed yards were enriched with ruminant-associated taxa and were distinct when compared to upwind PM assemblages. Furthermore, genes encoding resistance to tetracycline antibiotics were significantly more abundant in PM collected downwind of feed yards as compared to upwind.
Wind-dispersed PM from feed yards harbors antibiotics, bacteria, and ARGs.
There has recently been a great deal of interest in the effects of the sizes of communities on the social and economic conditions of settlements, drawing on theoretical and empirical work on complex ...systems. However, although it is clear that there is a series of relationships between the sizes of sites and their various attributes in a range of modern and non-modern contexts, it is not yet known whether these relationships extend to life
within
settlements, between different neighbourhoods, blocks, or individual households. In this article, I investigate whether this is the case by focusing on one site, Pompeii. The results show that there is indeed a series of relationships between the sizes of structures, the numbers and different kinds of rooms within them, and the numbers and different kinds of artefacts associated with them, which increase at a similar rate to those from other contexts. This demonstrates, for the first time, that the same scaling phenomena that have been identified across both contemporary and non-modern urban systems can also be found within the built environment of a single, well-documented ancient settlement. This suggests that the same, or similar, social network effects exist at multiple social, spatial, and temporal scales, from individual houses to entire cities, opening up the possibility of building a series of much more ambitious theoretical and empirical models of urbanism in future, which trace the variation both within and across settlements back to the net socio-economic and infrastructural consequences of embedding social networks within built environments.
Cell differentiation in yeast species is controlled by a reversible, programmed DNA-rearrangement process called mating-type switching. Switching is achieved by two functionally similar but ...structurally distinct processes in the budding yeast
and the fission yeast
In both species, haploid cells possess one active and two silent copies of the mating-type locus (a three-cassette structure), the active locus is cleaved, and synthesis-dependent strand annealing is used to replace it with a copy of a silent locus encoding the opposite mating-type information. Each species has its own set of components responsible for regulating these processes. In this review, we summarize knowledge about the function and evolution of mating-type switching components in these species, including mechanisms of heterochromatin formation,
locus cleavage, donor bias, lineage tracking, and environmental regulation of switching. We compare switching in these well-studied species to others such as
and the methylotrophic yeasts
and
We focus on some key questions: Which cells switch mating type? What molecular apparatus is required for switching? Where did it come from? And what is the evolutionary purpose of switching?
Peatlands contain one-third of the world's soil carbon (C). If destabilized, decomposition of this vast C bank could accelerate climate warming; however, the likelihood of this outcome remains ...unknown. Here, we examine peatland C stability through five years of whole-ecosystem warming and two years of elevated atmospheric carbon dioxide concentrations (eCO
). Warming exponentially increased methane (CH
) emissions and enhanced CH
production rates throughout the entire soil profile; although surface CH
production rates remain much greater than those at depth. Additionally, older deeper C sources played a larger role in decomposition following prolonged warming. Most troubling, decreases in CO
:CH
ratios in gas production, porewater concentrations, and emissions, indicate that the peatland is becoming more methanogenic with warming. We observed limited evidence of eCO
effects. Our results suggest that ecosystem responses are largely driven by surface peat, but that the vast C bank at depth in peatlands is responsive to prolonged warming.
Long acting insulin detemir administered intranasally for three weeks enhanced memory for adults with Alzheimer's disease dementia (AD) or amnestic mild cognitive impairment (MCI). The investigation ...of longer-term administration is necessary to determine whether benefits persist, whether they are similar to benefits provided by regular insulin, and whether either form of insulin therapy affects AD biomarkers.
The present study aimed to determine whether four months of treatment with intranasal insulin detemir or regular insulin improves cognition, daily functioning, and AD biomarkers for adults with MCI or AD.
This randomized, double-blind, placebo-controlled trial included an intent-to-treat sample consisting of 36 adults diagnosed with MCI or mild to moderate AD. Participants received placebo (n = 12), 40 IU of insulin detemir (n = 12), or 40 IU of regular insulin (n = 12) daily for four months, administered with a nasal delivery device. A cognitive battery was administered at baseline and after two and four months of treatment. MRI was administered for all participants and lumbar puncture for a subset (n = 20) at baseline and four months. The primary outcome was change from baseline to four months on a memory composite (sum of Z scores for delayed list and story recall). Secondary outcomes included: global cognition (Alzheimer's Disease Assessment Scale-Cognition), daily functioning (Dementia Severity Rating Scale), MRI volume changes in AD-related regions of interest, and cerebrospinal fluid AD markers.
The regular insulin treated group had better memory after two and four months compared with placebo (p < 0.03). No significant effects were observed for the detemir-assigned group compared with the placebo group, or for daily functioning for either group. Regular insulin treatment was associated with preserved volume on MRI. Regular insulin treatment was also associated with reduction in the tau-P181/Aβ42 ratio.
Future research is warranted to examine the mechanistic basis of treatment differences, and to further assess the efficacy and safety of intranasal insulin.
Over the past 4 decades, a number of numerical models have been developed to quantify the magnitude, investigate the spatial and temporal variations, and understand the underlying mechanisms and ...environmental controls of methane (CH4) fluxes within terrestrial ecosystems. These CH4 models are also used for integrating multi-scale CH4 data, such as laboratory-based incubation and molecular analysis, field observational experiments, remote sensing, and aircraft-based measurements across a variety of terrestrial ecosystems. Here we summarize 40 terrestrial CH4 models to characterize their strengths and weaknesses and to suggest a roadmap for future model improvement and application. Our key findings are that (1) the focus of CH4 models has shifted from theoretical to site- and regional-level applications over the past 4 decades, (2) large discrepancies exist among models in terms of representing CH4 processes and their environmental controls, and (3) significant data–model and model–model mismatches are partially attributed to different representations of landscape characterization and inundation dynamics. Three areas for future improvements and applications of terrestrial CH4 models are that (1) CH4 models should more explicitly represent the mechanisms underlying land–atmosphere CH4 exchange, with an emphasis on improving and validating individual CH4 processes over depth and horizontal space, (2) models should be developed that are capable of simulating CH4 emissions across highly heterogeneous spatial and temporal scales, particularly hot moments and hotspots, and (3) efforts should be invested to develop model benchmarking frameworks that can easily be used for model improvement, evaluation, and integration with data from molecular to global scales. These improvements in CH4 models would be beneficial for the Earth system models and further simulation of climate–carbon cycle feedbacks.
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