12 research outputs found
Exploration Behaviour Is Not Associated with Chick Provisioning in Great Tits
In biparental systems, members of the same pair can vary substantially in the amount of parental care they provide to offspring. The extent of this asymmetry should depend on the relative costs and benefits of care. Individual variation in personality is likely to influence this trade-off, and hence is a promising candidate to explain differences in care. In addition, plasticity in parental care may also be associated with personality differences. Using exploration behaviour (EB) as a measure of personality, we investigated these possibilities using both natural and experimental data from a wild population of great tits (Parus major). Contrary to predictions, we found no association between EB and natural variation in provisioning behaviour. Nor was EB linked to responsiveness to experimentally increased brood demand. These results are initially surprising given substantial data from other studies suggesting personality should influence investment in parental care. However, they are consistent with a recent study showing selection on EB is weak and highly context-specific in the focal population. This emphasises the difficulty faced by personality studies attempting to make predictions based on previous work, given that personalities often vary among populations of the same species
The Effectiveness of Contract Farming for Raising Income of Smallholder Farmers in Low- and Middle-Income Countries: a Systematic Review
Contract farming is used by an increasing number of firms as a preferred modality to source products from smallholder farmers in low and middle-income countries. Quality requirements of consumers, economies of scale in production or land ownership rights are common incentives for firms to offer contractual arrangements to farmers. Prices and access to key technology, key inputs or support services are the main incentives for farmers to enter into these contracts. There is great heterogeneity in contract farming, with differences in contracts, farmers, products, buyers, and institutional environments. The last decade shows a rapid increase in studies that use quasi-experimental research designs to assess the effects of specific empirical instances of contract farming on smallholders. The objective of this systematic review was to distill generalised inferences from this rapidly growing body of evidence. The review synthesised the studies in order to answer two questions: 1: What is known about the effect size of contract farming on income and food security of smallholder farmers in low- and middle-income countries? 2: Under which enabling or limiting conditions are contract farming arrangements effective for improving income and food security of smallholders
A Hazard-Aware Metric for Ordinal Multi-Class Classification in Pathology
Artificial Intelligence (AI) for decision support and diagnosis in pathology could provide immense value to society, improving patient outcomes and alleviating workload demands on pathologists. However, this potential cannot be realized until sufficient methods for testing and evaluation of such AI systems are developed and adopted. We present a novel metric for evaluation of multi-class classification algorithms for pathology, Error Severity Index (ESI), to address the needs of pathologists and pathology lab managers in evaluating AI systems
Modulation doping of GaAs/AlGaAs core-shell nanowires with effective defect passivation and high electron mobility
Reliable doping is required to realize many devices based on semiconductor nanowires. Group III-V nanowires show great promise as elements of high-speed optoelectronic devices, but for such applications it is important that the electron mobility is not compromised by the inclusion of dopants. Here we show that GaAs nanowires can be n-type doped with negligible loss of electron mobility. Molecular beam epitaxy was used to fabricate modulation-doped GaAs nanowires with Al0.33Ga0.67As shells that contained a layer of Si dopants. We identify the presence of the doped layer from a high-angle annular dark field scanning electron microscopy cross-section image. The doping density, carrier mobility, and charge carrier lifetimes of these n-type nanowires and nominally undoped reference samples were determined using the noncontact method of optical pump terahertz probe spectroscopy. An n-type extrinsic carrier concentration of 1.10 ± 0.06 à 1016 cm-3 was extracted, demonstrating the effectiveness of modulation doping in GaAs nanowires. The room-temperature electron mobility was also found to be high at 2200 ± 300 cm2 V-1 s-1 and importantly minimal degradation was observed compared with undoped reference nanowires at similar electron densities. In addition, modulation doping significantly enhanced the room-temperature photoconductivity and photoluminescence lifetimes to 3.9 ± 0.3 and 2.4 ± 0.1 ns respectively, revealing that modulation doping can passivate interfacial trap states
The C-terminal intact forms of periostin (iPTN) are surrogate markers for osteolytic lesions in experimental breast cancer bone metastasis
Periostin is an extracellular matrix protein that actively contributes to tumor progression and metastasis. Here, we hypothesized that it could be a marker of bone metastasis formation. To address this question, we used two polyclonal antibodies directed against the whole molecule or its C-terminal domain to explore the expression of intact and truncated forms of periostin in the serum and tissues (lung, heart, bone) of wild-type and periostin-deficient mice. In normal bones, periostin was expressed in the periosteum and specific periostin proteolytic fragments were found in bones, but not in soft tissues. In animals bearing osteolytic lesions caused by 4T1 cells, C-terminal intact periostin (iPTN) expression disappeared at the invasive front of skeletal tumors where bone-resorbing osteoclasts were present. In vitro, we found that periostin was a substrate for osteoclast-derived cathepsin K, generating proteolytic fragments that were not recognized by anti-periostin antibodies directed against iPTN. In vivo, using an in-house sandwich immunoassay aimed at detecting iPTN only, we observed a noticeable reduction of serum periostin levels (ââ26%; Pâ<â0.002) in animals bearing osteolytic lesions caused by 4T1 cells. On the contrary, this decrease was not observed in women with breast cancer and bone metastases when periostin was measured with a human assay detecting total periostin. Collectively, these data showed that mouse periostin was degraded at the bone metastatic sites, potentially by cathepsin K, and that the specific measurement of iPTN in serum should assist in detecting bone metastasis formation in breast cancer