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Adsorption of Cu2+ and Co2+ by synthetic imogolite, synthetic allophanes with a range of SiO2/ Al2O3 ratios, and allophanic clay fractions from volcanic ash soils was measured in an ionic medium of 0.05 M Ca(NO3)2. The effect of pH (and metal concentration) on adsorption was qualitatively similar for the synthetic and natural allophanes with relatively minor changes in behavior caused by variable SiO2/Al2O3 ratios. Cu and Co were chemisorbed by allophane at pH 5.0–5.5 and 6.9–7.2 (pH values for 50% adsorption level), respectively, with concomitant release of 1.6–1.9 protons/metal ion adsorbed. Quantitatively, adsorption by imogolite was less than that by the allophanes, presumably because of fewer sites available for chemisorption on the tubular structure of imogolite. Electron spin resonance studies of the imogolite and allophanes revealed that Cu2+ was adsorbed as a monomer on two types of surface sites. The preferred sites were likely adjacent AlOH groups binding Cu2+ by a binuclear mechanism; weaker bonding occurred at isolated AlOH or SiOH groups. These chemisorbed forms of Cu2+ were readily extracted by EDTA, CH3COOH, and metals capable of specific adsorption, but were not exchangeable. In addition, the H2O and/or OH− ligands of chemisorbed Cu2+ were readily displaced by NH3, with the formation of ternary Cu-ammonia-surface complexes.
The negative surface charge of synthetic allophanes with a range of Si/Al ratios decreased and positive charge increased with increasing alumina content at a given pH. The phosphate adsorption capacity also increased with increasing Al content. That this relationship between composition and chemical reactivity was not found for the soil allophanes is attributed to the presence of specifically adsorbed organic or inorganic anions on the natural material. Both synthetic and natural imogolites had a much lower capacity to adsorb phosphate than the allophanes and adsorbed anomalously high amounts of Cl− and ClO4− at high pH. It is proposed that intercalation of salt occurs in imogolite, although electron spin resonance studies using spin probes failed to reveal the trapping of small organic molecules in imogolite tubes. These spin probes in the carboxylated form did, however, suggest an electrostatic retention of carboxylate by imogolite and a more specific adsorption by allophane involving ligand exchange of surface hydroxyl. The results illustrate the inherent differences in charge and surface properties of allophane and imogolite despite the common structural unit which the two minerals incorporate.
The degree of flocculation of aqueous suspensions of microcrystalline goethite was measured in salts of monovalent, divalent and trivalent cations at pH 6.0–6.5 over a range of ionic strengths using light scattering measurements at 650 nm. Varying concentrations of soluble humic material as well as the organic ligands, salicylate and citrate, were tested for their effect on flocculation. It was found that KCl and NaCl induced flocculation at lower ionic strength than CaCl2, while AlCl3 favored dispersion at all ionic strengths tested. The simple organic ligands promoted flocculation at low concentration, with citrate having a more pronounced effect than salicylate. At higher concentrations, these ligands reversed their effect, inducing a more dispersed state of the oxide. The organic ligand effect on dispersibility was modified by the particular metal cation present, with Ca2+ being more conducive to flocculation than K+. Soluble humic materials affected goethite flocculation in a qualitatively similar way to that of the simple organic ligands, that is low concentrations favored flocculation while high concentrations induced dispersion. This dispersing effect was partially suppressed by the presence of Ca2+, and completely suppressed by Al3+. Thus, soluble humic substances at relatively high concentrations appear to have a marked dispersing effect on goethite in the absence of polyvalent cations, and a strongly flocculating effect in their presence.
The results can be explained qualitatively by a simple oxide surface charge model, in which chemi-sorption of multivalent cations or organic ligands alters the surface charge. Reactions that increase the magnitude of positive or negative surface charge favor dispersion, while those that reduce the magnitude of charge favor flocculation.
Young people may have elevated risk for poorer mental health during the coronavirus disease 2019 (COVID-19) pandemic, yet longitudinal studies documenting this impact are lacking. This study assessed changes in mental health and help-seeking since COVID-19 restrictions in young Australians, including gender differences.
Methods
Data were drawn from a recent subsample (n = 443; 60% female; Mage = 22.0) of a prospective cohort originally recruited in secondary school to complete annual surveys. The subsample completed an additional COVID-19 survey during COVID-19 restrictions (May–June 2020), which was compared to responses from their latest annual survey (August 2019–March 2020). Mixed effect models with time and gender as the primary predictors were conducted for: (i) scores on the Patient Health Questionnaire Depression 9-item (PHQ-9) and Generalised Anxiety Disorder 7-item (GAD-7) modules assessed before and during COVID-19 restrictions, and (ii) self-reported help-seeking from a health professional in February 2020, and the month preceding May–June 2020.
Results
Mean symptom scores increased from before to during COVID-19 restrictions on the PHQ-9 (coefficient: 1.29; 95% CI 0.72–1.86) and GAD-7 (0.78; 95% CI 0.26–1.31), but there was no increase in help-seeking over time (odds ratio 0.50; 95% CI 0.19–1.32). There was no evidence of differential changes by gender.
Conclusions
This study found increases in depression and anxiety symptoms but not greater help-seeking among young Australian adults during the first wave of the pandemic. Increasing availability and awareness of accessible treatment options and psychoeducation is critical, as well as further research into risk and protective factors to help target treatment to this vulnerable age group.
The role of the Eurasian badger (Meles meles) as a wildlife host has complicated the management of bovine tuberculosis (bTB) in cattle. Badger ranging behaviour has previously been found to be altered by culling of badgers and has been suggested to increase the transmission of bTB either among badgers or between badgers and cattle. In 2014, a five-year bTB intervention research project in a 100 km2 area in Northern Ireland was initiated involving selective removal of dual path platform (DPP) VetTB (immunoassay) test positive badgers and vaccination followed by release of DPP test negative badgers (‘Test and Vaccinate or Remove’). Home range sizes, based on position data obtained from global positioning system collared badgers, were compared between the first year of the project, where no DPP test positive badgers were removed, and follow-up years 2–4 when DPP test positive badgers were removed. A total of 105 individual badgers were followed over 21 200 collar tracking nights. Using multivariable analyses, neither annual nor monthly home ranges differed significantly in size between years, suggesting they were not significantly altered by the bTB intervention that was applied in the study area.
The burden of disease attributable to alcohol and other drug (AOD) use in young people is considerable. Prevention can be effective, yet few programs have demonstrated replicable effects. This study aimed to replicate research behind Climate Schools: Alcohol and Cannabis course among a large cohort of adolescents.
Methods
Seventy-one secondary schools across three States participated in a cluster-randomised controlled trial. Year 8 students received either the web-based Climate Schools: Alcohol and Cannabis course (Climate, n = 3236), or health education as usual (Control, n = 3150). Outcomes were measured via self-report and reported here for baseline, 6- and 12-months for alcohol and cannabis knowledge, alcohol, cannabis use and alcohol-related harms.
Results
Compared to Controls, students in the Climate group showed greater increases in alcohol- [standardised mean difference (SMD) 0.51, p < 0.001] and cannabis-related knowledge (SMD 0.49, p < 0.001), less increases in the odds of drinking a full standard drink[(odds ratio (OR) 0.62, p = 0.014], and heavy episodic drinking (OR 0.49, p = 0.022). There was no evidence for differences in change over time in the odds of cannabis use (OR 0.57, p = 0.22) or alcohol harms (OR 0.73, p = 0.17).
Conclusions
The current study provides support for the effectiveness of the web-based Climate Schools: Alcohol and Cannabis course in increasing knowledge and reducing the uptake of alcohol. It represents one of the first trials of a web-based AOD prevention program to replicate alcohol effects in a large and diverse sample of students. Future research and/or adaptation of the program may be warranted with respect to prevention of cannabis use and alcohol harms.
The procedure for synthesizing proto-imogolite (an acid-soluble hydroxy-aluminium orthosilicate complex) and imogolite (a tubular aluminosilicate mineral) was used to produce ferruginous aluminosilicates over a range of Al/Fe ratios to determine whether Fe3+ can be incorporated in the imogolite structure. Analysis of the synthesized products by transmission electron microscopy, electron diffraction, and IR spectroscopy indicated that, while imogolite was formed in the presence of iron, increased Fe3+ in the systems caused the formation of ferrihydrite and poorly-organized aluminosilicates resembling proto-imogolite allophane. Treatment of these materials with Na-citrate/dithionite/bicarbonate dissolved the ferrihydrite and poorly-organized aluminosilicate, and concentrated products with tubular morphology. Analysis of the structural Fe3+ by ESR spectroscopy suggested that little or no Fe3+ was incorporated in the structure of imogolite, although the less crystalline proto-imogolite allophane may have accommodated some structural Fe3+. A separate iron-rich product, identified as ferrihydrite, was formed at low Al/Fe ratios. Mössbauer spectroscopic analysis of 57Fe3+ doped at very low levels into proto-imogolite and imogolite indicated that the sites of substitution were better defined in the latter. At least part of this Fe3+ may have been incorporated in the structure of boehmite, an impurity formed during synthesis.
Despite its brief history, Berlin Dada (1918–20) produced a glut of chronicles and memoirs, as if to immortalize its ephemeral insurgency. Its self-appointed chronicler, Richard Huelsenbeck, tried to harness this compulsion to memorialize in the service of Dadaist agitation he hoped would unleash a revolutionary time and redeem the failure of the communist uprisings at the end of World War I. his seditious temporality was based on two incompatible concepts of revolution: a properly political notion aimed at overthrowing an unjust regime and a vitalist discourse aimed at tapping into the circular low of life. he clash of the two modes of revolutionary time is enacted in Hannah Höch's photomontage “Cut with the Kitchen Knife” (1919). he spectral temporality that sustains both is conjured by the Dada Almanac (1920), a literary compendium that doubles as a quirky inquiry into political normativity and an inluential paradigm of Dada's self-legitimation.
The aim of this study was to examine the population structure, transmission and spatial relationship between genotypes of Shiga toxin-producing Escherichia coli (STEC) and Campylobacter jejuni, on 20 dairy farms in a defined catchment. Pooled faecal samples (n = 72) obtained from 288 calves were analysed by real-time polymerase chain reaction (rtPCR) for E. coli serotypes O26, O103, O111, O145 and O157. The number of samples positive for E. coli O26 (30/72) was high compared to E. coli O103 (7/72), O145 (3/72), O157 (2/72) and O111 (0/72). Eighteen E. coli O26 and 53 C. jejuni isolates were recovered from samples by bacterial culture. E. coli O26 and C. jejuni isolates were genotyped using pulsed-field gel electrophoresis and multilocus sequence typing, respectively. All E. coli O26 isolates could be divided into four clusters and the results indicated that E. coli O26 isolates recovered from calves on the same farm were more similar than isolates recovered from different farms in the catchment. There were 11 different sequence types of C. jejuni isolated from the cattle and 22 from water. An analysis of the population structure of C. jejuni isolated from cattle provided evidence of clustering of genotypes within farms, and among groups of farms separated by road boundaries.
The Australian Imaging, Biomarkers and Lifestyle (AIBL) Flagship Study of Ageing is a prospective study of 1,112 individuals (211 with Alzheimer's disease (AD), 133 with mild cognitive impairment (MCI), and 768 healthy controls (HCs)). Here we report diagnostic and cognitive findings at the first (18-month) follow-up of the cohort. The first aim was to compute rates of transition from HC to MCI, and MCI to AD. The second aim was to characterize the cognitive profiles of individuals who transitioned to a more severe disease stage compared with those who did not.
Methods:
Eighteen months after baseline, participants underwent comprehensive cognitive testing and diagnostic review, provided an 80 ml blood sample, and completed health and lifestyle questionnaires. A subgroup also underwent amyloid PET and MRI neuroimaging.
Results:
The diagnostic status of 89.9% of the cohorts was determined (972 were reassessed, 28 had died, and 112 did not return for reassessment). The 18-month cohort comprised 692 HCs, 82 MCI cases, 197 AD patients, and one Parkinson's disease dementia case. The transition rate from HC to MCI was 2.5%, and cognitive decline in HCs who transitioned to MCI was greatest in memory and naming domains compared to HCs who remained stable. The transition rate from MCI to AD was 30.5%.
Conclusion:
There was a high retention rate after 18 months. Rates of transition from healthy aging to MCI, and MCI to AD, were consistent with established estimates. Follow-up of this cohort over longer periods will elucidate robust predictors of future cognitive decline.
Erythropoietin (EPO) gene therapy can be used for several purposes; however, its effects on reproductive performance are unknown. The aim of this study was to evaluate the toxicological effects of non-viral (EPO) gene transfer on sperm motility, viability, morphology and concentration. Rabbit EPO cDNA was cloned into a pTarget mammalian expression vector. Rabbits were administered with: (1) pTarget/EPO vector, (2) recombinant human EPO (rHuEpo) and (3) saline (control). Both pTarget/EPO and rHuEpo significantly increased (P < 0.05) hematocrit levels 1 week after injection and they remained significantly higher than the control for up to 5 weeks (P < 0.05), showing that both EPO treatments were effective in stimulating the production of red blood cells in rabbits. The EPO gene transfer or rHuEPO administration had no significant effect (P > 0.05) on sperm motility, vigor, viability, concentration or morphology in the testis.
The gene expression of Bax, Bcl-2, survivin and p53, following in vitro maturation of equine oocytes, was compared in morphologically distinct oocytes and cumulus cells. Cumulus–oocyte complexes (COC) were harvested and divided into two groups: G1 – morphologically healthy cells; and G2 – less viable cells or cells with some degree of atresia. Total RNA was isolated from both immature and in vitro matured COC and real-time reverse transcription polymerase chain reaction (qRT-PCR) was used to quantify gene expression. Our results showed there was significantly higher expression of survivin (P < 0.05) and lower expression of p53 (P < 0.01) in oocytes compared with cumulus cells in G1. No significant difference in gene expression was observed following in vitro maturation or in COC derived from G1 and G2. However, expression of the Bax gene was significantly higher in cumulus cells from G1 (P < 0.02).
A better understanding of the factors regulating feed efficiency and their potential as predictors of feed efficiency in cattle is needed. Therefore, the potential of three classes of traits, namely, feeding behavior characteristics: daily time at feeder (TF; min/day), time per meal (TM; min), meal size (MS; g DM), eating rate (ER; g DM/min), number of daily meals (NM) and daily visits to the feeder (VF); infrared (IR) thermography traits (°C): eye (EY), cheek (CK), snout (SN), ribs (RB) and hind area (HA); and glucocorticoid levels: fecal cortisol metabolites (FCM; ng/g) and plasma cortisol (PC; ng/ml) as predictors of efficiency were evaluated in 91 steers (436 ± 37 kg) over 2 years (Y1 = 46; Y2 = 45). Additionally, the individual traits of each of these three classes were combined to define three single traits. Individual daily feed intake of a corn silage and high-moisture corn-based diet was measured using an automated feeding system. Body weight and thermographs were taken every 28 days over a period of 140 days. Four productive performance traits were calculated: daily dry matter intake (DMI), average daily gain (ADG), feed to gain ratio (F : G) and residual feed intake (RFI). Steers were also classified into three RFI categories (low-, medium- and high-RFI). Among the feeding behavior characteristics, MS and ER were correlated with all efficiency traits (range: 0.26 to 0.75). Low-RFI (more efficient steers) had smaller MS, lower ER and fewer VF in comparison to high-RFI steers. Less efficient steers (high-RFI) performed more VF during the nocturnal period than more efficient steers. More efficient steers had lower CK and SN temperatures than less efficient steers (28.1°C v. 29.2°C and 30.0°C v. 31.2°C), indicating greater energetic efficiency for low-RFI steers. In terms of glucocorticoids, PC was not correlated with efficiency traits. In contrast, more efficient steers had higher FCM in comparison to less efficient steers (51.1 v. 31.2 ng/g), indicating that a higher cortisol baseline is related to better feed efficiency. The overall evaluation of the three classes of traits revealed that feeding behavior, IR thermography and glucocorticoids accounted for 18%, 59% and 7% of the total variation associated with RFI, respectively. These classes of traits have usefulness in the indirect assessment of feed efficiency in cattle. Among them, IR thermography was the most promising alternative to screen cattle for this feed efficiency. These findings might have application in selection programs and in the better understanding of the biological basis associated with productive performance.