We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60$\to$–70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.

The history of maize in Central America and surrounding areas has implications for the slow transition from hunting and gathering to agriculture. The spread of early forms of domesticated maize from southern Mexico across Mesoamerica and into South America has been dated to about 8,700–6,500 years ago on the basis of a handful of studies relying primarily on the analysis of pollen, phytoliths, or starch grains. Recent genomic data from southern Belize have been used to identify Archaic period south-to-north population movements from lower Central America, suggesting this migration pattern as a mechanism that introduced genetically improved maize races from South America. Gradually, maize productivity increased to the point that it was suitable for use as a staple crop. Here we present a summary of paleoecological data that support the late and uneven entry of maize into the Maya area relative to other regions of Central America and identify the Pacific coastal margin as the probable route by which maize spread southward into Panama and South America. We consider some implications of the early appearance of maize for Late Archaic populations in these areas; for example, with respect to the establishment of sedentary village life.

In a survey of hospitals and of patients with Clostridioides difficile infection (CDI), we found that most facilities had educational materials or protocols for education of CDI patients. However, approximately half of CDI patients did not recall receiving education during their admission, and knowledge deficits regarding CDI prevention were common.

This paper presents the results of the work of the new field initiative launched by the British Museum at the Darband-i Rania pass in the Kurdistan Region of Iraq. The pass is located at the northeastern corner of Lake Dokan, where, though now subsumed into the lake, the Lower Zab flows from the Peshdar into the Rania Plain. It is a strategic location on a major route from Mesopotamia into Iran, and control of both the road and the river must always have been important. The aim of the work, which commenced in autumn of 2016, is to explore a cluster of sites that commanded the pass, with a particular focus on the first millennium b.c. Excavation is being carried out principally at two sites: Qalatga Darband, a large fortified site at the western end of the pass, and Usu Aska, a fort inside the pass itself. The occupations of these two sites are predominantly Parthian and Assyrian respectively. Smaller operations have also been carried out at Murad Rasu, a multi-period site situated on a headland across the waters on the southern shore of Lake Dokan. The results have included the discovery at Qalatga Darband of a monumental complex built of stone and roofed with terracotta roof tiles containing the smashed remains of Hellenistic statuary. Other features indicative of Hellenistic material culture are Mediterranean-type oil-presses and Corinthian column bases and capitals. At Usu Aska remains are being uncovered of an Assyrian fortification of massive proportions.

Vestibular impairment (VI) and cognitive impairment (CI) are risk factors for senior falls. We tested the feasibility of a self-directed 12-week vestibular rehabilitation (VR) program in Memory Clinic patients (65 years+) with a fall, CI and VI. We assessed recruitment, exercise adherence and ability to complete questionnaires/assessments. Twelve patients with CI and falls were screened and 8/12 (75% – prevalence) had VI. All patients completed the screening tests/questionnaires (100% – completeness); 7/8 patients were recruited (87.5% – recruitment); 1/7 (85.7% – attrition) patient attended follow-up. VI is prevalent in patients with CI experiencing falls but traditional VR is not feasible, so a novel delivery of VR must be explored.

Ongoing challenges in maintaining optimum manual cleaning and disinfection of hospital rooms have created increased interest in “no-touch” decontamination technologies including the use of ultraviolet light (UV). Trials have shown that some UV devices can decrease surface contamination and reduce healthcare-associated infections. Despite substantial marketing of these devices for use in healthcare settings, few data are available regarding the doses of UV-C necessary to yield desired reductions in healthcare pathogens and the ability of mobile devices to deliver adequate doses to various surfaces in patient rooms. This review summarizes the physical aspects of UV that affect the doses delivered to surfaces, the UV-C doses needed to yield 3 log10 reductions of several important healthcare-associated pathogens, the doses of UV-C that can be achieved in various locations in patient rooms using mobile UV-C devices, and methods for measuring UV doses delivered to surfaces.

n-3 Fatty acids are associated with better cardiovascular and cognitive health. However, the concentration of EPA, DPA and DHA in different plasma lipid pools differs and factors influencing this heterogeneity are poorly understood. Our aim was to evaluate the association of oily fish intake, sex, age, BMI and APOE genotype with concentrations of EPA, DPA and DHA in plasma phosphatidylcholine (PC), NEFA, cholesteryl esters (CE) and TAG. Healthy adults (148 male, 158 female, age 20–71 years) were recruited according to APOE genotype, sex and age. The fatty acid composition was determined by GC. Oily fish intake was positively associated with EPA in PC, CE and TAG, DPA in TAG, and DHA in all fractions (P≤0·008). There was a positive association between age and EPA in PC, CE and TAG, DPA in NEFA and CE, and DHA in PC and CE (P≤0·034). DPA was higher in TAG in males than females (P<0·001). There was a positive association between BMI and DPA and DHA in TAG (P<0·006 and 0·02, respectively). APOE genotype×sex interactions were observed: the APOE4 allele associated with higher EPA in males (P=0·002), and there was also evidence for higher DPA and DHA (P≤0·032). In conclusion, EPA, DPA and DHA in plasma lipids are associated with oily fish intake, sex, age, BMI and APOE genotype. Such insights may be used to better understand the link between plasma fatty acid profiles and dietary exposure and may influence intake recommendations across population subgroups.

A DNA marker inoculated onto shared portable equipment in surgical and medical intensive care units disseminated widely to surfaces in patient rooms and provider work areas and to other types of portable equipment. These results demonstrate the potential for contaminated portable equipment to serve as a vector for dissemination of pathogens.

Infect Control Hosp Epidemiol 2017;38:1247–1249

Terbacil tolerance was investigated in field-selected alfalfa strain ‘OK 182.’ Growth response studies indicated a 78% increase in tolerance over the unselected parental cultivar ‘Cimarron.’ Photosynthetic electron transport was inhibited similarly in both cultivars when isolated thylakoids were exposed to a wide range of terbacil concentration indicating that tolerance was not due to reduced sensitivity at the site-of-action. ‘OK 182’ took up an average of 22% less 14C-terbacil over the 6-d labeling period. A similar proportion of total radiolabel was translocated in both strains indicating that differential translocation was not a factor in the tolerance mechanism. Once in the leaves, terbacil was rapidly metabolized to a glucosidic conjugate by both strains. Terbacil and total concentration of metabolites in leaf tissues were 17% and 33% lower in ‘OK 182’ than in ‘Cimarron,’ respectively. Enhanced tolerance to terbacil in ‘OK 182’ was attributed to decreased terbacil uptake.

A 3-yr field study was conducted in peanut in which weed control systems with varying levels of herbicides, cultivation inputs, or both were supplemented with mowing to remove weeds extending above the crop canopy. Highest yield and net returns were consistently obtained with the highest level of herbicide/cultivation inputs, and mowing was of no value. However, mowing was consistently beneficial to yield and net return when the only other weed control inputs were paraquat and 2,4-DB applied at 4 wk after planting (WAP) and cultivation at 10 WAP. In the absence of any other weed control inputs, mowing was detrimental in a drought stress year, but beneficial in years with near-normal growing conditions. Although disease incidence was aggravated by the lack of weed control inputs, it was generally independent of mowing.

Paleolimnological and archaeological records that span 3500 years from Lake Titicaca and the surrounding Bolivian–Peruvian altiplano demonstrate that the emergence of agriculture (ca. 1500 B.C.) and the collapse of the Tiwanaku civilization (ca. A.D. 1100) coincided with periods of abrupt, profound climate change. The timing and magnitude of climate changes are inferred from stratigraphic evidence of lake-level variation recorded in14C-dated lake-sediment cores. Paleo-lake levels provide estimates of drainage basin water balance. Archaeological evidence establishes spatial and temporal patterns of agricultural field use and abandonment. Prior to 1500 B.C., aridity in the altiplano precluded intensive agriculture. During a wetter period from 1500 B.C. to A.D. 1100, the Tiwanaku civilization and its immediate predecessors developed specialized agricultural methods that stimulated population growth and sustained large human settlements. A prolonged drier period (ca. A.D. 1100–1400) caused declining agricultural production, field abandonment, and cultural collapse.

Research was conducted in 1997 and 1998 to evaluate narrow row spacing and glufosinate in glufosinate-resistant corn. Glufosinate-resistant corn was planted in 51- and 102-cm row spacings at the same plant populations. Herbicide treatments included glufosinate alone and in different herbicide combinations. Atrazine plus glufosinate enhanced Palmer amaranth control compared to glufosinate alone. Control of johnsongrass, ivyleaf morningglory, entireleaf morningglory, Texas panicum, smellmellon, browntop panicum, and toothed spurge with glufosinate was greater than 82%. Common sunflower control with glufosinate was greater than 95%. Atrazine followed by glufosinate applications provided at least 94% control of all species and was the most consistent herbicide system used. Row spacing had little effect on weed control. Crop injury to glufosinate-resistant corn was minimal with glufosinate and atrazine plus glufosinate combinations.

Wildlife managers must consider the public's preferences for wildlife population levels when determining management policies. In 1996, Maryland farmers, hunters and the general public were surveyed to determine their preferences for increasing, maintaining, or decreasing deer population numbers. Using a random utility theoretic framework with an ordered response probit model, the factors that explain preferences such as residential location, socioeconomic characteristics, landscape damage, agricultural yield loss and vehicle accidents were analyzed.

The dichotomous choice contingent valuation survey format collects inexact information on willingness to pay (WTP), that is, whether WTP is greater or less than the bid price. Sometimes researchers make the precise conjecture that certain respondents have zero WTP using information from follow-up motive questions. But follow-up questions are designed to provide information on respondents’ motives, not refined information on the magnitude of WTP. Assuming that certain respondents have WTP = $0.00 is beyond the design of follow-up questions. The paper's results show that unless information from follow-up questions is utilized within the limitations of survey design, welfare and model parameter estimates are likely to have high standard errors leading to inappropriate policy prescriptions.