Effect of grazing on ship rat density in forest fragments of lowland Waikato, New Zealand

Ship rat (Rattus rattus) density was assessed by snap-trapping during summer and autumn in eight indigenous forest fragments (mean 5 ha) in rural landscapes of Waikato, a lowland pastoral farming district of the North Island, New Zealand. Four of the eight were fenced and four grazed. In each set of four, half were connected with hedgerows, gullies or some other vegetative corridor to nearby forest and half were completely isolated. Summer rat density based on the number trapped in the first six nights was higher in fenced (mean 6.5 rats ha–1) than in grazed fragments (mean 0.5 rats ha–1; P = 0.02). Rats were eradicated (no rats caught and no rat footprints recorded for three consecutive nights) from all eight fragments in January–April 2008, but reinvaded within a month; time to eradication averaged 47 nights in fenced and 19 nights in grazed fragments. A second six-night trapping operation in autumn, 1–3 months after eradication, found no effect of fencing (P = 0.73). Connectedness to an adjacent source of immigrants did not influence rat density within a fragment in either season (summer P = 0.25, autumn P = 0.67). An uncalibrated, rapid (one-night) index of ship rat density, using baited tracking tunnels set in a 50 × 50 m grid, showed a promising relationship with the number of rats killed per hectare over the first six nights, up to tracking index values of c. 30% (corresponding to c. 3–5 rats ha–1). The index will enable managers to determine if rat abundance is low enough to achieve conservation benefits. Our results confirm a dilemma for conservation in forest fragments. Fencing protects vegetation, litter and associated ecological processes, but also increases number of ship rats, which destroy seeds, invertebrates and nesting birds. Maximising the biodiversity values of forest fragments therefore requires both fencing and control of ship rats

Resilience of New Zealand indigenous forest fragments to impacts of livestock and pest mammals

A number of factors have combined to diminish ecosystem integrity in New Zealand indigenous lowland forest fragments surrounded by intensively grazed pasture. Livestock grazing, mammalian pests, adventive weeds and altered nutrient input regimes are important drivers compounding the changes in fragment structure and function due to historical deforestation and fragmentation. We used qualitative systems modelling and empirical data from Beilschmiedia tawa dominated lowland forest fragments in the Waikato Region to explore the relevance of two common resilience paradigms – engineering resilience and ecological resilience – for addressing the conservation management of forest fragments into the future. Grazing by livestock and foraging/predation by introduced mammalian pests both have direct detrimental impacts on key structural and functional attributes of forest fragments. Release from these perturbations through fencing and pest control leads to partial or full recovery of some key indicators (i.e. increased indigenous plant regeneration and cover, increased invertebrate populations and litter mass, decreased soil fertility and increased nesting success) relative to levels seen in larger forest systems over a range of timescales. These changes indicate that forest fragments do show resilience consistent with adopting an engineering resilience paradigm for conservation management, in the landscape context studied. The relevance of the ecological resilience paradigm in these ecosystems is obscured by limited data. We characterise forest fragment dynamics in terms of changes in indigenous species occupancy and functional dominance, and present a conceptual model for the management of forest fragment ecosystems

CD4+ Memory T Cells at Home in the Tissue: Mechanisms for Health and Disease

During the last 10 years, a population of clonally expanded T cells that take up permanent residence in non-lymphoid tissues has been identified. The localization of these tissue resident memory (TRM) cells allows them to rapidly respond at the site of antigen exposure, making them an attractive therapeutic target for various immune interventions. Although most studies have focused on understanding the biology underlying CD8 TRMs, CD4 T cells actually far outnumber CD8 T cells in barrier tissues such as lung and skin. Depending on the immune context, CD4 TRM can contribute to immune protection, pathology, or tissue remodeling. Although the ability of CD4 T cells to differentiate into heterogeneous effector and memory subsets has been well-established, how this heterogeneity manifests within the TRM compartment and within different tissues is just beginning to be elucidated. In this review we will discuss our current understanding of how CD4 TRMs are generated and maintained as well as a potential role for CD4 TRM plasticity in mediating the balance between beneficial and pathogenic immune responses

Predator control improves nesting success in Waikato forest fragments

Predation at nests contributes importantly to current declines of New Zealand forest birds. We monitored the survival of natural and artificial arboreal nests in small forest remnants south-west of Hamilton, where ship rat (Rattus rattus) and possum (Trichosurus vulpecula) abundances were also being measured in Summer 2008/09. Artificial cup nests (N = 77) were placed in replicated blocks with and without pest control, in both December and January. Natural nests (N = 11, five bird species) were observed from 13 October to 23 December 2008 in a forest with no pest control. Digital video cameras identified ship rats, brushtail possums and harrier hawks (Circus approximans) as predators of eggs and chicks. There was no difference between artificial and natural nests in daily survival rates monitored in December in a block with no pest control, suggesting that artificial nests are reasonable surrogates for natural nests. Bite marks on clay eggs, other diagnostic sign, and DNA swabbed from real and clay eggs confirmed ship rats and possums were the major introduced predators at artificial nests. Bite marks also confirmed that harriers contribute to nest failure. Removal of ship rats and possums in December improved the 14-day probability of survival of artificial nests, from P = 0.63 (95% CI 0.45–0.77) in the non-treatment block to P = 0.88 (0.74–0.95) in the treatment blocks. In January, the 14-day probability of survival in all three blocks was intermediate at 0.80 (0.69–0.87), and the variation between them could not be explained by including pest control in the model. The abundance of ship rats apparently declined even in the non-treatment block over this time, for unknown reasons. Our data from tawa (Beilschmiedia tawa) forest remnants confirm that control of ship rats and possums alone is sufficient to improve nesting success of small arboreal birds in North Island forests

Evaluation of the health-related quality of life of children in Schistosoma haematobium-endemic communities in Kenya: a cross-sectional study.

BACKGROUND: Schistosomiasis remains a global public health challenge, with 93% of the ~237 million infections occurring in sub-Saharan Africa. Though rarely fatal, its recurring nature makes it a lifetime disorder with significant chronic health burdens. Much of its negative health impact is due to non-specific conditions such as anemia, undernutrition, pain, exercise intolerance, poor school performance, and decreased work capacity. This makes it difficult to estimate the disease burden specific to schistosomiasis using the standard DALY metric. METHODOLOGY/PRINCIPAL FINDINGS: In our study, we used Pediatric Quality of Life Inventory (PedsQL), a modular instrument available for ages 2-18 years, to assess health-related quality of life (HrQoL) among children living in a Schistosoma haematobium-endemic area in coastal Kenya. The PedsQL questionnaires were administered by interview to children aged 5-18 years (and their parents) in five villages spread across three districts. HrQoL (total score) was significantly lower in villages with high prevalence of S. haematobium (-4.0%, p<0.001) and among the lower socioeconomic quartiles (-2.0%, p<0.05). A greater effect was seen in the psychosocial scales as compared to the physical function scale. In moderate prevalence villages, detection of any parasite eggs in the urine was associated with a significant 2.1% (p<0.05) reduction in total score. The PedsQL reliabilities were generally high (Cronbach alphas ≥0.70), floor effects were acceptable, and identification of children from low socioeconomic standing was valid. CONCLUSIONS/SIGNIFICANCE: We conclude that exposure to urogenital schistosomiasis is associated with a 2-4% reduction in HrQoL. Further research is warranted to determine the reproducibility and responsiveness properties of QoL testing in relation to schistosomiasis. We anticipate that a case definition based on more sensitive parasitological diagnosis among younger children will better define the immediate and long-term HrQoL impact of Schistosoma infection

Analyzing collaborative learning processes automatically

In this article we describe the emerging area of text classification research focused on the problem of collaborative learning process analysis both from a broad perspective and more specifically in terms of a publicly available tool set called TagHelper tools. Analyzing the variety of pedagogically valuable facets of learners’ interactions is a time consuming and effortful process. Improving automated analyses of such highly valued processes of collaborative learning by adapting and applying recent text classification technologies would make it a less arduous task to obtain insights from corpus data. This endeavor also holds the potential for enabling substantially improved on-line instruction both by providing teachers and facilitators with reports about the groups they are moderating and by triggering context sensitive collaborative learning support on an as-needed basis. In this article, we report on an interdisciplinary research project, which has been investigating the effectiveness of applying text classification technology to a large CSCL corpus that has been analyzed by human coders using a theory-based multidimensional coding scheme. We report promising results and include an in-depth discussion of important issues such as reliability, validity, and efficiency that should be considered when deciding on the appropriateness of adopting a new technology such as TagHelper tools. One major technical contribution of this work is a demonstration that an important piece of the work towards making text classification technology effective for this purpose is designing and building linguistic pattern detectors, otherwise known as features, that can be extracted reliably from texts and that have high predictive power for the categories of discourse actions that the CSCL community is interested in

Long-lived T follicular helper cells retain plasticity and help sustain humoral immunity

CD4; +; memory T cells play an important role in protective immunity and are a key target in vaccine development. Many studies have focused on T central memory (T; cm; ) cells, whereas the existence and functional significance of long-lived T follicular helper (T; fh; ) cells are controversial. Here, we show that T; fh; cells are highly susceptible to NAD-induced cell death (NICD) during isolation from tissues, leading to their underrepresentation in prior studies. NICD blockade reveals the persistence of abundant T; fh; cells with high expression of hallmark T; fh; markers to at least 400 days after infection, by which time T; cm; cells are no longer found. Using single-cell RNA-seq, we demonstrate that long-lived T; fh; cells are transcriptionally distinct from T; cm; cells, maintain stemness and self-renewal gene expression, and, in contrast to T; cm; cells, are multipotent after recall. At the protein level, we show that folate receptor 4 (FR4) robustly discriminates long-lived T; fh; cells from T; cm; cells. Unexpectedly, long-lived T; fh; cells concurrently express a distinct glycolytic signature similar to trained immune cells, including elevated expression of mTOR-, HIF-1-, and cAMP-regulated genes. Late disruption of glycolysis/ICOS signaling leads to T; fh; cell depletion concomitant with decreased splenic plasma cells and circulating antibody titers, demonstrating both unique homeostatic regulation of T; fh; and their sustained function during the memory phase of the immune response. These results highlight the metabolic heterogeneity underlying distinct long-lived T cell subsets and establish T; fh; cells as an attractive target for the induction of durable adaptive immunity

Wildlife ecological risk assessment in the 21st century: Promising technologies to assess toxicological effects

Despite advances in toxicity testing and the development of new approach methodologies (NAMs) for hazard assessment, the ecological risk assessment (ERA) framework for terrestrial wildlife (i.e., air‐breathing amphibians, reptiles, birds, and mammals) has remained unchanged for decades. While survival, growth, and reproductive endpoints derived from whole-animal toxicity tests are central to hazard assessment, nonstandard measures of biological effects at multiple levels of biological organization (e.g., molecular, cellular, tissue, organ, organism, population, community, ecosystem) have the potential to enhance the relevance of prospective and retrospective wildlife ERAs. Other factors (e.g., indirect effects of contaminants on food supplies and infectious disease processes) are influenced by toxicants at individual, population, and community levels, and need to be factored into chemically based risk assessments to enhance the “eco” component of ERAs. Regulatory and logistical challenges often relegate such nonstandard endpoints and indirect effects to post-registration evaluations of pesticides and industrial chemicals and contaminated site evaluations. While NAMs are being developed, to date, their applications in ERAs focused on wildlife have been limited. No single magic tool or model will address all uncertainties in hazard assessment. Modernizing wildlife ERAs will likely entail combinations of laboratory‐ and field‐derived data at multiple levels of biological organization, knowledge collection solutions (e.g., systematic review, adverse outcome pathway frameworks), and inferential methods that facilitate integrations and risk estimations focused on species, populations, interspecific extrapolations, and ecosystem services modeling, with less dependence on whole‐animal data and simple hazard ratios