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This long-anticipated work shares the aims of its celebrated companion: namely, to provide an introduction for students and a reference for researchers to the techniques, results, and terminology of multiplicative number theory. This volume builds on the earlier one (which served as an introduction to basic, classical results) and focuses on sieve methods. This area has witnessed a number of major advances in recent years, e.g. gaps between primes, large values of Dirichlet polynomials and zero density estimates, all of which feature here. Despite the fact that the book can serve as an entry to contemporary mathematics, it remains largely self-contained, with appendices containing background or material more advanced than undergraduate mathematics. Again, exercises, of which there is a profusion, illustrate the theory or indicate ways in which it can be developed. Each chapter ends with a thorough set of references, which will be essential for all analytic number theorists.
Since lack of culture-specific foods in dietary assessment methods may bias reported dietary intake, we identified foods and dishes consumed by residents not born in Sweden and describe consequences for reported foods and nutrient intake using a culturally adapted dietary assessment method. Design consisted of cross-sectional data collection using (semi-)qualitative methods of dietary assessment (and national diet survey instrument RiksmatenFlex) with subsequent longitudinal data collection using quantitative methods for method comparison (December 2020–January 2023). Three community-based research groups were recruited that consisted of mothers born in Sweden, Syria/Iraq, and Somalia, with a median age of 34, 37, and 36 years, respectively. Women born in Syria/Iraq and Somalia who had lived in Sweden for approximately 10 years, reported 78 foods to be added to RiksmatenFlex. In a subsequent study phase, 69% of these foods were reported by around 90% of the ethnic minority groups and contributed to 17% of their reported energy intake. However, differences between the three study groups in median self-reported energy intake remained (Sweden 7.19 MJ, Syria/Iraq 5.54 MJ, and Somalia 5.69 MJ). The groups also showed differences in relative energy contribution from fats and carbohydrates, as well as differences in energy intake from food groups such as bread and sweet snacks. We conclude that a dietary assessment instrument containing culture-specific foods could not resolve group differences in reported energy intake, although these foods provided content validity and contributed 17% of energy intake. The dietary habits collected in this study serve to develop new dietary assessment instruments.
Unsustainable hunting, both illegal and legal, has led to the extirpation of many species. In the last 35 years giraffe Giraffa spp. populations have declined precipitously, with extinctions documented in seven African countries. Amongst the various reasons for these population declines, poaching is believed to play an important role in some areas. Giraffes are primarily hunted for consumption and for the use of their body parts as trophies and in traditional medicine. However, the socio-economic factors that correlate with the use of giraffe body parts are not well understood. We conducted our study in Tsavo Conservation Area, Kenya, which experiences high levels of poaching. We used semi-structured surveys amongst 331 households to document how giraffe body parts are typically acquired and their intended use (i.e. trophy, medicinal or consumptive). We then used logistic regression models to assess the correlations between nine socio-economic factors and the use of giraffe body parts. We found that giraffe body parts had mostly consumptive and trophy uses. One-time suppliers, opportunistic access and widely known markets were the most common means of acquiring giraffe body parts. Results from our models showed that three variables (gender: men, occupation: tourism worker, and land ownership) were correlated significantly and positively with the use of giraffe body parts. We describe the complex links between socio-economic factors and the use of giraffe body parts and highlight the importance of implementing mitigation measures adapted to local contexts to combat a challenge that many species of conservation concern are facing.
The purpose of this study was to assess impact of different volumes of exercise as well as cumulative moderate to vigorous physical activity (MVPA) on energy intake (EI) and diet quality, as assessed by the Healthy Eating Index-2010(HEI-2010), across a 12-month weight maintenance intervention. Participants were asked to attend group behavioural sessions, eat a diet designed for weight maintenance and exercise either 150, 225 or 300 min/week. Dietary intake was assessed by 3-d food records, and MVPA was assessed by accelerometry. Two hundred and twenty-four participants (42·5 years of age, 82 % female) provided valid dietary data for at least one time point. There was no evidence of group differences in EI, total HEI-2010 score or any of the HEI-2010 component scores (all P > 0·05). After adjusting for age, sex, time, group and group-by-time interactions, there was an effect of cumulative MVPA on EI (1·08, P = 0·04), total HEI-2010 scores (–0·02, P = 0·003), Na (–0·006, P = 0·002) and empty energy scores (–0·007, P = 0·004. There was evidence of a small relationship between cumulative daily EI and weight (β: 0·00187, 95 % CI 0·001, P = 0·003). However, there was no evidence for a relationship between HEI total score (β: −0·006, 95 % CI 0·07, 0·06) or component scores (all P > 0·05) and change in weight across time. The results of this study suggest that increased cumulative MVPA is associated with clinically insignificant increases in EI and decreases in HEI.
Carnivore population declines are a time-sensitive global challenge in which mitigating decreasing populations requires alignment of applied practice and research priorities. However, large carnivore conservation is hindered by gaps among research, conservation practice and policy formation. One potential driver of this research–implementation gap is research bias towards charismatic species. Using depredation of livestock by large carnivores in sub-Saharan Africa as a case study, we examined whether taxonomic bias could be detected and explored the potential effects of such a bias on the research–implementation gap. Via a literature review, we compared the central large carnivore species in research to the species identified as the primary livestock depredator. We detected a substantial misalignment between these factors for two species. Spotted hyaenas Crocuta crocuta were the most common depredator of livestock (58.5% of studies), but were described as a central species among only 20.7% of the studies. In comparison, African lions Panthera leo were the most common central species (45% of studies) but were the primary depredator in just 24.4% of studies. Such patterns suggest that taxonomic bias is prevalent within this research. Although spotted hyaenas may depredate livestock most often, their low charisma in comparison to sympatric species such as the African lion and leopard Panthera pardus may be limiting research-informed conservation efforts for them. Efforts to mitigate human-carnivore conflict designed for one species may not be applicable to another co-occurring species, and thus, taxonomic bias could undermine the efficacy of interventions built to reduce livestock depredation by carnivores.
This paper presents a physics-based macroscale model for the densification of dry snow which provides for a smooth transition between densification by grain-boundary sliding (stage 1) and densification by power-law creep (stage 2). The model uses established values of the stage 1 and 2 densification rates away from the transition zone and two transition parameters with a simple physical basis: the transition density and the half-width of the transition zone. It has been calibrated using density profiles from the SUMup database and physically based expressions for the transition parameters have been derived. The transition model produces better predictions of the depth of the nominal bubble close-off horizon than the Herron and Langway model, both in its classical form and in a recent version with re-optimised densification rates.