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Kinetoplastid parasites are responsible for both human and animal diseases across the globe where they have a great impact on health and economic well-being. Many species and life cycle stages are difficult to study due to limitations in isolation and culture, as well as to their existence as heterogeneous populations in hosts and vectors. Single-cell transcriptomics (scRNA-seq) has the capacity to overcome many of these difficulties, and can be leveraged to disentangle heterogeneous populations, highlight genes crucial for propagation through the life cycle, and enable detailed analysis of host–parasite interactions. Here, we provide a review of studies that have applied scRNA-seq to protozoan parasites so far. In addition, we provide an overview of sample preparation and technology choice considerations when planning scRNA-seq experiments, as well as challenges faced when analysing the large amounts of data generated. Finally, we highlight areas of kinetoplastid research that could benefit from scRNA-seq technologies.
To evaluate whether a multipronged pilot intervention promoting healthier beverage consumption improved at-home beverage consumption and weight status among young children.
In this exploratory pilot study, we randomly assigned four childcare centres to a control (delayed-intervention) condition or a 12-week intervention that promoted consumption of healthier beverages (water, unsweetened low- or non-fat milk) and discouraged consumption of less-healthy beverages (juice, sugar-sweetened beverages, high-fat or sweetened milk). The multipronged intervention was delivered via childcare centres; simultaneously targeted children, parents and childcare staff; and included environmental changes, policies and education. Outcomes were measured at baseline and immediately post-intervention and included children’s (n 154) at-home beverage consumption (assessed via parental report) and overweight/obese status (assessed via objectively measured height and weight). We estimated intervention impact using difference-in-differences models controlling for children’s demographics and classroom.
Two northern California cities, USA, 2013–2014.
Children aged 2–5 years and their parents.
Relative to control group children, intervention group children reduced their consumption of less-healthy beverages from baseline to follow-up by 5·9 ounces/d (95 % CI −11·2, −0·6) (–174·5 ml/d; 95 % CI –331·2, –17·7) and increased their consumption of healthier beverages by 3·5 ounces/d (95 % CI −2·6, 9·5) (103·5 ml/d; 95 % CI –76·9, 280·9). Children’s likelihood of being overweight decreased by 3 percentage points (pp) in the intervention group and increased by 3 pp in the control group (difference-in-differences: −6 pp; 95 % CI −15, 3).
Our exploratory pilot study suggests that interventions focused comprehensively on encouraging healthier beverage consumption could improve children’s beverage intake and weight. Findings should be confirmed in longer, larger studies.
Ensuring ready access to free drinking-water in schools is an important strategy for prevention of obesity and dental caries, and for improving student learning. Yet to date, there are no validated instruments to examine water access in schools. The present study aimed to develop and validate a survey of school administrators to examine school access to beverages, including water and sports drinks, and school and district-level water-related policies and practices.
Survey validity was measured by comparing results of telephone surveys of school administrators with on-site observations of beverage access and reviews of school policy documents for any references to beverages. The semi-structured telephone survey included items about free drinking-water access (sixty-four items), commonly available competitive beverages (twenty-nine items) and water-related policies and practices (twenty-eight items). Agreement between administrator surveys and observation/document review was calculated using kappa statistics for categorical variables, and Pearson correlation coefficients and t tests for continuous variables.
Public schools in the San Francisco Bay Area, California, USA.
School administrators (n 24).
Eighty-one per cent of questions related to school beverage access yielded κ values indicating substantial or almost perfect agreement (κ>0·60). However, only one of twenty-eight questions related to drinking-water practices and policies yielded a κ value representing substantial or almost perfect agreement.
This school administrator survey appears reasonably valid for questions related to beverage access, but less valid for questions on water-related practices and policies. This tool provides policy makers, researchers and advocates with a low-cost, efficient method to gather national data on school-level beverage access.
Glacial landforms and drift stratigraphy in central Magellan Strait, southernmost Chile, document repeated fluctuations during the last glacial cycle of outlet lobes from an ice cap centered over the southern Andes. The lobes developed comparatively low-gradient profiles because of low basal shear stresses over soft deformable beds and this made them sensitive to even small-scale changes in the mass balance. Such low profiles and rapid calving in deep proglacial lakes during deglaciation may have made the Magellan ice lobe particularly responsive to climatic fluctuations during the last glacial cycle, and to advance and retreat over considerable distances. Study of the glacial landforms and drift stratigraphy has led to the identification of at least five glacier advances to limits at and south of the Segunda Angostura. Fragments of mollusc shells contained in basal till indicate marine incursions between some advances, thus documenting extensive deglaciation. A partial chronology based on amino acid studies and radiocarbon dating suggests that five of these advances occurred during the last glacial cycle. The most extensive advances may have culminated during substages of marine isotope stage 5 (substage 5b or 5d) and/or during stage 4. Slightly less extensive advances occurred between ca. 28,000 and 14,000 yr B.P.
Public agencies at all levels of government and other organizations that manage archaeological resources often face the problem of many undertakings that collectively impact large numbers of individually significant archaeological resources. Such situations arise when an agency is managing a large area, such as a national forest, land management district, park unit, wildlife refuge, or military installation. These situations also may arise in regard to large-scale development projects, such as energy developments, highways, reservoirs, transmission lines, and other major infrastructure projects that cover substantial areas. Over time, the accumulation of impacts from small-scale projects to individual archaeological resources may degrade landscape or regional-scale cultural phenomena. Typically, these impacts are mitigated at the site level without regard to how the impacts to individual resources affect the broader population of resources. Actions to mitigate impacts rarely are designed to do more than avoid resources or ensure some level of data recovery at single sites. Such mitigation activities are incapable of addressing research question at a landscape or regional scale.
Observations at a number of frequencies indicate that for at least two pulsars the average pulse shape has a slow but quite definite frequency dependence. Figure 1 shows average pulse shapes for CP 1919, CP 0950 and CP 1133. With the exception of those at 408 MHz these results were obtained at Parkes. The 408 MHz pulse shapes were obtained at Jodrell Bank by Lyne and Rickett. Circumstances of the observations are listed in Table I. Linearly polarized feeds were used at all frequencies.
Solubilizing alkyl chains play a crucial role in the design of semiconducting polymers because they define the materials solubility and processability as well as both the crystallinity and solid-state microstructure. In this paper, we present a scarcely explored design approach by attaching the alkyl side chains on one side (cis-) or on both sides (trans-) of the conjugated backbone. We further investigate the effects of this structural modification on the solid-state properties of the polymers and on the charge-carrier mobilities in organic thin-film transistors.
We are undertaking an observational program using the ATCA to monitor the intraday variability (IDV) of a sample of sources at 4.8 and 8.6 GHz. The sources were selected to include the known strong southern IDV sources plus a number of sources whose IDV was recently discovered. The present monitoring program will extend over a full year in order to search for any annual cycle that may be present in the long-term IDV characteristics of these sources. In this paper we discuss the observing strategy and data analysis, and present the first results from our observations.
Flux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, ∼10%, vary. Their variability falls into several categories: sources whose spectral classification is, at best, ephemeral on a timescale of years; sources with a stable GPS classification that vary, but retain their classification; and a small number of sources that exhibit interstellar scintillation, but that maintain a mean GPS spectrum. Existing data on GPS sources with higher frequency peaks, ≥3 GHz, reveals that many such sources vary. However, the majority of these sources possess a GPS spectrum only during outbursts, and hence should perhaps be classified as ephemeral GPS sources. In addition, significant levels of circular polarisation have been found in a number of GPS sources, both amongst the variables and non-variables. Remarkable amongst these is PKS 1519–273, which possesses strong and variable circular polarisation, and which exhibits IDV in all Stokes parameters.
Long distance migration by adults of Chortoicetes terminifera (Wlk.) in Australia was shown to be associated with the accumulation of fat-body lipid. Lipid was accumulated if the plant growth index was 0·3 or more within a week of the final moult; when the plant growth index was less than 0·3, there was little fat accumulation. Locusts with large amounts of fat-body lipid migrated on nights with warm strong winds, while those with little persisted.
Cardiac myocytes and fibroblasts are essential elements of myocardial
tissue structure and function. In vivo, myocytes constitute the
majority of cardiac tissue volume, whereas fibroblasts dominate in
numbers. In vitro, cardiac cell cultures are usually designed to
exclude fibroblasts, which, because of their maintained proliferative
potential, tend to overgrow the myocytes. Recent advances in
microstructuring of cultures and cell growth on elastic membranes have
greatly enhanced in vitro preservation of tissue properties and
offer a novel platform technology for producing more in vivo-like
models of myocardium. We used microfluidic techniques to grow
two-dimensional structured cardiac tissue models, containing both myocytes
and fibroblasts, and characterized cell morphology, distribution, and
coupling using immunohistochemical techniques. In vitro findings
were compared with in vivo ventricular cyto-architecture. Cardiac
myocytes and fibroblasts, cultured on intersecting 30-μm-wide collagen
tracks, acquire an in vivo-like phenotype. Their spatial
arrangement closely resembles that observed in native tissue: Strands of
highly aligned myocytes are surrounded by parallel threads of fibroblasts.
In this in vitro system, fibroblasts form contacts with other
fibroblasts and myocytes, which can support homogeneous and heterogeneous
gap junctional coupling, as observed in vivo. We conclude that
structured cocultures of cardiomyocytes and fibroblasts mimic in
vivo ventricular tissue organization and provide a novel tool for
in vitro research into cardiac electromechanical function.