Recent outbreaks of various infectious diseases have highlighted the ever-present need to understand the drivers of the outbreak and spread of disease. Although much of the research investigating diseases focuses on single infections, natural systems are dominated by multiple infections. These infections may occur simultaneously, but are often acquired sequentially, which may alter the outcome of infection. Using waterfleas (Daphnia magna) as a model organism, we examined the outcome of sequential and simultaneous multiple infections with 2 microsporidian parasites (Ordospora colligata and Hamiltosporidium tvaerminnensis) in a fully factorial design with 9 treatments and 30 replicates. We found no differences between simultaneous and sequential infections. However, H. tvaerminnensis fitness was impeded by multiple infection due to increased host mortality, which gave H. tvaerminnensis less time to grow. Host fecundity was also reduced across all treatments, but animals infected with O. colligata at a younger age produced the fewest offspring. As H. tvaerminnensis is both horizontally and vertically transmitted, this reduction in offspring may have further reduced H. tvaerminnensis fitness in co-infected treatments. Our findings suggest that in natural populations where both species co-occur, H. tvaerminnensis may evolve to higher levels of virulence following frequent co-infection by O. colligata.

The extent to which findings in bilingualism research are contingent on specific analytic choices, experimental designs, or operationalisations, is currently unknown. Poor availability of data, analysis code, and materials has hindered the development of cumulative lines of research. In this review, we survey current practices and advocate a credibility revolution in bilingualism research through the adoption of minimum standards of transparency. Full disclosure of data and code is necessary not only to assess the reproducibility of original findings, but also to test the robustness of these findings to different analytic specifications. Similarly, full provision of experimental materials and protocols underpins assessment of both the replicability of original findings, as well as their generalisability to different contexts and samples. We illustrate the review with examples where good practice has advanced the agenda in bilingualism research and highlight resources to help researchers get started.

In the context of 90 adult Japanese learners of English with diverse second language experience and 10 native speakers, this study examined the linguistic characteristics and learner profiles of low-, mid- and high-level fluency performance. The participants’ spontaneous speech samples were initially rated by 10 native listeners for global fluency on a 9-point scale (1 = dysfluent, 9 = very fluent), and then divided into four proficiency groups via cluster analyses: low (n = 29), mid (n = 30), high (n = 31), and native (n = 10). Next, the data set was analyzed for the number of pauses within/between clauses, articulation rate, and the frequency of repetitions/self-corrections. According to the results of a series of analyses of variance, the frequency of final-clause pauses differentiated low- and mid-level fluency performance; the number of mid-clause pauses differentiated mid- and high-level performance; and articulation rate differentiated high-level and nativelike performance. The analyses also found that the participants’ second language fluency was significantly associated with their length of residence profiles (0–18 years), but not with their age of arrival profiles (19–40 years).

The current project examined whether and to what degree continued L2 input, operationalized as length of residence (LOR), and age of acquisition (AOA), defined as the first intensive exposure to the target language, can be predictive of adult Japanese learners’ production of word-initial English /ɹ/. Data were collected from 65 participants, consisting of three groups of Japanese learners of English (n = 13 for Short-, Mid-, and Long-LOR groups, respectively) and two groups of baseline speakers (n = 13 for Japanese- and English-Baseline groups, respectively). Their production of /ɹ/ was elicited via three oral tasks (i.e., word reading, sentence reading, timed picture description). Acoustic analyses were carried out along four dimensions: third formant (F3), second formant (F2), first formant (F1) frequencies, and formant transition duration. The results demonstrated that (a) all learners reached native-like proficiency with respect to the use of existing cues (F2, transition duration) within approximately one year of LOR, (b) their performance was negatively related to AOA to some degree, and (c) longer LOR was predictive of the development of the new cue (F3). These results suggest that late L2 speech sound acquisition and proficiency may be characterized by different levels of phonetic processing.

To investigate potential causes of L2 performance deficits that correlate with age of onset, we use a computational model to explore the individual contributions of L1 entrenchment and aspects of memory development. Since development and L1 entrenchment almost invariably coincide, studying them independently is seldom possible in humans. To avoid this confound, we study neural network models that learn to solve gender assignment and agreement tasks in Spanish and French. We model the learner as a collection of recurrent cell assemblies that subserve working memory and are facilitated by trainable long-term connections. Varying the time-course over which assemblies and connections are added allows us to compare small, growing, child-like networks to fixed-size adult-like ones. Networks undergo variable-length exposure to L1 before L2 onset to control the amount of L1 entrenchment. This model, by allowing us independent control of both variables, lends us a novel glimpse of all sides of their interaction and affords a rare test of the less-is-more hypothesis. Network comparisons suggest that final L2 proficiency declines as L2 onset delays increase relative to L1, implicating an L1 entrenchment effect. However, aspects of memory development during learning play a key role in mitigating these impairments, lending support to less-is-more as a contributor to sensitive periods.

Background: People with dementia may have adverse outcomes following periods of acute hospitalization. This study aimed to explore the effects of age upon hospitalization outcomes for patients with dementia in comparison to patients without dementia.

Methods: Data extracted from the New South Wales Admitted Patient Care Database for people aged 50 years and over for the period July 2006 to June 2007 were linked to create person-based records relating to both single and multiple periods of hospitalization. This yielded nearly 409,000 multi-day periods of hospitalization relating to almost 253,000 persons. Using ICD-10-AM codes for dementia and other principal diagnoses, the relationship between age and hospitalization characteristics were examined for people with and without dementia.

Results: Dementia was age-related, with 25% of patients aged 85 years and over having dementia compared with 0.9% of patients aged 50–54 years. People with dementia were more likely to be admitted for fractured femurs, lower respiratory tract infections, urinary tract infections and head injuries than people without dementia. Mean length of stay for admissions for people with dementia was 16.4 days and 8.9 days for those without dementia. People with dementia were more likely than those without to be re-admitted within three months for another multi-day stay. Mortality rates and transfers to nursing home care were higher for people with dementia than for people without dementia. These outcomes were more pronounced in younger people with dementia.

Conclusion: Outcomes of hospitalization vary substantially for patients with dementia compared with patients without dementia and these differences are frequently most marked among patients aged under 65 years.

The present study investigates the syntactic competence of bilingual Portuguese–German returnees who have lost regular contact with their L2 (German). The main criterion which distinguishes the participants is the age of input loss. This allows their division into two main groups: speakers who lost German input during early childhood (between ages seven and ten) and speakers who were eleven or older when they moved away from the German environment. Focusing on verb placement in main and embedded clauses, the available data show strong evidence of the existence of a stabilization phase following the acquisition period. The speakers who lost L2 input earlier than age eleven show significantly more syntactic deficits than the other speakers. However, the observed attrition effects seem to be the result of insufficient L2 activation, rather than the expression of undergoing competence loss.

This paper questions assumptions about reminiscence and looks at definitions of it. Functions of different types of reminiscence are examined and distinctions are drawn between these and autobiographical memories. Methodologies of eliciting reminiscences are critically considered. Finally, types and amounts of reminiscence are related to life style and age group.

In April–May 1986, 180 male and 218 female Glossina morsitans morsitans Westwood, each less than 1 day old, were marked uniquely and released unfed on Redcliff Island, Lake Kariba, Zimbabwe. Flies were recaptured on ox fly-rounds carried out twice daily for 6 months; marks were recorded and the flies released. For females, 56% were recaptured at leastonce; the capture probability for a given 9-day period changed with age, falling from 0.32 after birth to 0.16 by 30 days and rising above 0.5 by 80 days. For males, 57% were recaptured; the probability was 0.21 for age less than 9 days, but > 0.77 for all older flies. The capture probabilities and fly-round catches were used to estimate the change with age in the daily mortality. Female mortality was 6.8% shortly after emergence, < 1% for ages 20–50 days and rose to 5% by 130 days—a pattern similar to that for laboratory reared tsetse. Male daily mortality was 8.3% after emergence, fellto 5.5% by 9 days, then rose continuously to more than 10% by 30 days. The mortality changes are related to age rather than climate. Tsetse caught on ox fly-rounds from a natural population were aged using ovarian dissection and wing-fray analysis. The age distribution (corrected using the capture probabilities from Redcliff) was consistent with the idea that, here too, mortality increased with age.