Received 11Revised Although in many social sciences there is a radical division between studies based on 13 quantitative (e.g. statistical) and qualitative (e.g. ethnographic) methodologies and their associated epistemological commitments, agent-based simulation fits into neither camp, 15and should be capable of modelling both quantitative and qualitative data. Nevertheless, most agent-based models (ABMs) are founded on quantitative data. This paper 17 explores some of the methodological and practical problems involved in basing an ABM on participant observation and proposes some advice for modellers. 19Keywords: Agent-based models; qualitative data; ethnography. The right question isn't: Does the number mean anything? The right ques-

The penetration characteristics of supersonic molecular beam injection (SMBI) have been studied on the HL-2A tokamak. The signals from the tangential D α array and CCD camera clearly show that the SMBI from the low field side consists of a slow component (SC) and a fast component (FC) because of a small percentage of H 2 present in the D 2 reservoir. The FC can penetrate more deeply than the SC, e.g. 8.5 cm inside the last closed flux surface, while the SC is around 4 cm. The penetration depth of the SMBI is weakly dependent on plasma parameters before injection and its backing pressure. Fuelling efficiency of SMBI is also estimated because it is one of the key issues in fusion plasmas. Typical fuelling efficiency of SMBI is 30-60% for the limiter configuration on the HL-2A tokamak. The variation of the decay time of the post-SMBI electron density is more responsible for the large scatter of the measured fuelling efficiencies than the different injection depths.

Low temperature is an environmental stress factor that is always been applied in research on improving crop growth, productivity, and quality of crops. Polyunsaturated fatty acids (PUFAs) play an important role in cold tolerance, so its genetic manipulation of the PUFA contents in crops has led to the modification of cold sensitivity. In this study, we over-expressed an ω-3 fatty acid desaturase from Glycine max (GmFAD3A) drove by a maize ubiquitin promoter in rice. Compared to the wild type (ZH11), ectopic expression of GmFAD3A increased the contents of lipids and total PUFAs. Seed germination rates in GmFAD3A transgenic rice were enhanced under low temperature (15 °C). Moreover, cold tolerance and survival ratio were significantly improved in GmFAD3A transgenic seedlings. Malondialdehyde (MDA) content in GmFAD3A transgenic rice was lower than that in WT under cold stress, while proline content obviously increased. Meanwhile, the activities of superoxide dismutase (SOD), hydroperoxidase (CAT), and peroxidase (POD) increased substantially in GmFAD3A transgenic rice after 4 h of cold treatment. Taken together, our results suggest that GmFAD3A can enhances cold tolerance and the seed germination rate at a low temperature in rice through the accumulation of proline content, the synergistic increase of the antioxidant enzymes activity, which finally ameliorated the oxidative damage.

An ideal bone repair scaffold is expected to possess superior architectural characteristics to facilitate the adhesion, proliferation, and migration of bone‐repair‐related cells, while excluding nonosteogenic cells and fibrous tissues from interfering with normal bone regeneration. Unfortunately, such scaffold material has rarely been reported. Herein, nanocomposite scaffolds with a radially ordered porous structure are presented, manufactured using a modified directional freeze‐casting method, and are promising bone defect repair materials to satisfy this requirement. The prepared nanocomposite scaffolds consist of a natural bio‐macromolecule, chitosan, and bioactive hydroxyapatite nanoparticles derived from porcine cortical bone, demonstrating favorable biocompatibility and biological functions. Both in vitro cell studies and in vivo animal studies reveal the great superiority of the radially oriented porous structure of the scaffolds in guiding bone regeneration, while simultaneously preventing the invasion of surrounding nonosteogenic cells and fibrous tissue, compared to the axially oriented porous structure. This work indicates the distinctive potential of radially oriented porous scaffolds for repairing tabular and lacunar bone defects.

Uniform and porous chitosan-based microparticles with injectable and shape-memory properties are particularly attractive due to their promising application potential for tissue engineering and regenerative medicine. However, simple and efficient methods for producing this kind of microparticle are still desirable. In this study, we report that uniform, injectable, and shape-memory chitosan microsponges were efficiently prepared by combining microfluidic emulsion with further freezing and in situ thawing processes without using any potentially cytotoxic chemical cross-linker. The produced chitosan microsponges have controllable size and could be easily injected with syringe needles. Structural observations confirmed that the chitosan microsponge had an interconnected porous structure with pore size of several micrometers and could withstand a large compressive strain of ∼93% and then recover ∼96% of its initial diameter without structural damage. The chitosan microsponges showed a high porosity (∼84%) and swelling ratio (∼3800%) as well as good antibacterial activity. Additionally, an in vitro cell coculturing investigation revealed that they also had good biocompatibility and exhibited great superiority to support cell adhesion and proliferation in three dimensions. The kind of chitosan microsponge presented here has great potential to serve as cell carriers for biomedical applications, especially as injectable scaffolds for regeneration and reconstruction of tissue defects.