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Neurogenesis in the Drosophila central brain progresses dynamically in order to generate appropriate numbers of neurons during different stages of development. Thus, a central challenge in neurobiology is to reveal the molecular and genetic mechanisms of neurogenesis timing. Here, we found that neurogenesis is significantly impaired when a novel mutation, Nuwa, is induced at early but not late larval stages. Intriguingly, when the Nuwa mutation is induced in neuroblasts of olfactory projection neurons (PNs) at the embryonic stage, embryonic-born PNs are generated, but larval-born PNs of the same origin fail to be produced. Through molecular characterization and transgenic rescue experiments, we determined that Nuwa is a loss-of-function mutation in Drosophila septin interacting protein 1 (sip1). Furthermore, we found that SIP1 expression is enriched in neuroblasts, and RNAi knockdown of sip1 using a neuroblast driver results in formation of small and aberrant brains. Finally, full-length SIP1 protein and truncated SIP1 proteins lacking either the N- or C-terminus display different subcellular localization patterns, and only full-length SIP1 can rescue the Nuwa-associated neurogenesis defect. Taken together, these results suggest that SIP1 acts as a crucial factor for specific neurogenesis programs in the early developing larval brain.

Understanding the significance of genetic variants in the noncoding genome is emerging as the next challenge in human genomics. We used the power of 11,257 whole-genome sequences and 16,384 heptamers (7-nt motifs) to build a map of sequence constraint for the human species. This build differed substantially from traditional maps of interspecies conservation and identified regulatory elements among the most constrained regions of the genome. Using new Hi-C experimental data, we describe a strong pattern of coordination over 2 Mb where the most constrained regulatory elements associate with the most essential genes. Constrained regions of the noncoding genome are up to 52-fold enriched for known pathogenic variants as compared to unconstrained regions (21-fold when compared to the genome average). This map of sequence constraint across thousands of individuals is an asset to help interpret noncoding elements in the human genome, prioritize variants and reconsider gene units at a larger scale.

High-density (∼ 80/um2) vertical InAs nanowires (NWs) with small diameters (∼ 28 nm) were grown on bare Si (111) substrates by means of two-step metal organic chemical vapor deposition. There are two critical factors in the growth process: (1) a critical nucleation temperature for a specific In molar fraction (approximately 1.69 × 10−5 atm) is the key factor to reduce the size of the nuclei and hence the diameter of the InAs NWs, and (2) a critical V/III ratio during the 2nd step growth will greatly increase the density of the InAs NWs (from 45 μm−2 to 80 μm−2) and at the same time keep the diameter small. The high-resolution transmission electron microscopy and selected area diffraction patterns of InAs NWs grown on Si exhibit a Wurtzite structure and no stacking faults. The observed longitudinal optic peaks in the Raman spectra were explained in terms of the small surface charge region width due to the small NW diameter and the increase of the free electron concentration, which was consistent with the TCAD program simulation of small diameter (

NH3 flow rate during AlGaN barrier layer growth not only affects the growth efficiency and surface morphology as a result of parasitic reactions but also influences the concentration of carbon impurity in the AlGaN barrier. Carbon, which decomposes from metal precursors, plays a role in electron compensation for AlGaN/GaN HEMT. No 2-dimensional electron gas (2-DEG) was detected in the AlGaN/GaN structure if grown with 0.5 slm of NH3 due to the presence of higher carbon impurity (2.6 × 1019 cm−2). When the NH3 flow rate increased to 6.0 slm, the carbon impurity reduced to 2.10 × 1018 atom cm−3 and the 2 DEG electron density recovered to 9.57 × 1012 cm−2.

Genetic factors modifying the blood metabolome have been investigated through genome-wide association studies (GWAS) of common genetic variants and through exome sequencing. We conducted a whole-genome sequencing study of common, low-frequency and rare variants to associate genetic variations with blood metabolite levels using comprehensive metabolite profiling in 1,960 adults. We focused the analysis on 644 metabolites with consistent levels across three longitudinal data collections. Genetic sequence variations at 101 loci were associated with the levels of 246 (38%) metabolites (P ≤ 1.9 × 10-11). We identified 113 (10.7%) among 1,054 unrelated individuals in the cohort who carried heterozygous rare variants likely influencing the function of 17 genes. Thirteen of the 17 genes are associated with inborn errors of metabolism or other pediatric genetic conditions. This study extends the map of loci influencing the metabolome and highlights the importance of heterozygous rare variants in determining abnormal blood metabolic phenotypes in adults.

We demonstrate fluorescent Fe embedded magnetic nanodiamonds by ion implantation and two-step annealing. The diamond characteristics with a highly ordered core and a graphite surface layer are maintained after the implantation process. After the two-step annealing process, a bright red fluorescence associated with nitrogen-vacancy centers is observed. These new fluorescent magnetic nanodiamonds can be used as a dual-function in vivo tracer with both optical visibility and magnetic resonance imaging capabilities. They are potentially useful for the more advanced in vivo biological and medical applications.

Strain-relieved GaSb quantum dots on GaAs can be achieved by either periodic interfacial misfit (IMF) or the conventional Stranski–Krastanov (SK) growth modes by changing the growth parameters. In this study, the Sb interfacial treatment was employed to improve the GaSb crystal quality including low defect density, smooth surface morphology, and high hole mobility. This technique yields two-dimensional (2D) islands with a height as low as 1.7 nm and width up to 190 nm in the IMF growth mode. In contrast to the interfacial treatments conventionally employed in the initial strain relaxation of GaSb/GaAs hererostructure, the Sb treatment promotes the formation of strong Ga-Sb bonds on the surface of the grown island, which effectively reduces the interfacial free energy and thus promotes the formation of 2D islands. With the Sb interfacial treatment, a high-relaxation 100-nm GaSb epilayer was grown on the GaAs substrate, the epilayers was strain relaxed and exhibited enhanced electrical properties with a high hole mobility of ~667 cm2 V−1 s−1 and with superior optical properties as evidenced by the photoluminescence B-line peak. The results of this study demonstrate an effective interfacial-treatment growth technique to relax the initial strain for the highly mismatched GaSb layers grown on a GaAs substrate.

School-age children receive external stimuli to understand the world and acquire various life skills through various learning behaviors. The process of children’s learning requires appropriate teaching methods, including children’s physical and mental status, special needs, and behavior, in order to provide learning aids, as appropriate, to help children acquire language, body movements, social skills, and other media, effectively take the user as the starting point to fit the needs of users, and observe binding and participatory designs to become a new research direction. In view of the rapid development of science and technology, the main purpose of this study is to explore a learning aids system suitable for school-age children, including the attributes, results, and elements to help children learn smoothly. It is difficult to understand the behavior and psychology of school-age children from traditional research methods, thus, the best way is to understand them is through interactions. Empathic design, which is the current research direction of the Design and Research Center, focuses on how designers propose design solutions based on the feelings experience, creativity, and understanding of users. This study is carried out according to the empathic design model, where the main procedure is Participant Observation to describe the behavioral phenomenon of school-age children, and Laddering interviews are applied to obtain qualitative data, conduct implication matrix analysis, and create a Streamlined Hierarchical Value Map according to the design guidelines and other steps to help designers and school-age children use the learning aids system to obtain a consensus, including system hardware and software development reference. The main research contribution is to respond to the needs of children in all aspects of life, put forward excellent learning aids system design guidelines, and then, help the learning development of children.

In this study, we investigate the effect of the shading factor of the front grid pattern on concentrated solar cell efficiency, taking the trade-off between the series resistance of the electrodes and the amount of incident light into consideration. We examine the thermal effect with regard to five different circle-grid electrode patterns of the front contact. The front contacts with different grid patterns affect the characteristics of light-concentrated-type GaAs single-junction solar cells. The device parameters analyzed include the open-circuit voltage (Voc), short-circuit current (Isc), fill factor (FF) and conversion efficiency (η). The results of our study show that for a concentration ratio greater than 60x with AM1.5G, the device with a shading factor of 7.1% has the best cell efficiency of 27.05%, due to the smaller current crowding at the center spot. The results indicate that the conversion efficiency of solar cells can be improved by establishing a compromise between the shading effect and the series resistance effect.

This work describes optical and electrical characteristics of InGaP/GaAs/Ge triple-junction (T-J) solar cells with CdS quantum dots (QDs) fabricated by a novel chemical solution. With the anti-reflective feature at long wavelength and down-conversion at UV regime, the CdS quantum dot effectively enhance the overall power conversion efficiency more than that of a traditional GaAs-based device. Experimental results indicate that CdS quantum dot can enhance the short-circuit current by 0.33 mA/cm2, which is observed for the triple-junction solar cells with CdS QDs of about 3.5 nm in diameter. Moreover, the solar cell conversion efficiency is improved from 28.3% to 29.0% under one-sun AM 1.5 global illumination I–V measurement.

This study adopts the P/V ratio developed from the residual income valuation model to examine whether Taiwan’s IT companies with more intellectual capital are more likely to be mispriced by the stock market. We focus on four types of intellectual capital: human capital (measured by employees holding graduate degrees and ratio of labor costs to net sales), innovation capital (measured by R&D intensity and royalty ratio), process capital (measured by working capital turnover and fixed asset turnover), and relational capital (measured by marketing expense ratio and sales growth rate). Using 751 firm-observations in Taiwan’s IT industry during 2003–2006, the empirical results show that Taiwan’s stock market appears to overprice IT companies’ innovation capital but underprice their human, process, and relational capital. Notably, the mispricing problem is more prominent on the human capital than on the other three types of intellectual capital. A further test indicates that the mispricing of intellectual capital is due to Taiwan’s domestic investors rather than foreign institutional investors. Particularly, the mispricing problem is more prominent on the human and relational capital. The implications of these findings are discussed.

We propose the problem of finding broadcast medians in heterogeneous networks. A heterogeneous network is represented by a graph G=(V,E), in which each edge has a weight that denotes the communication time between its two end vertices. The overall delay of a vertex v?V(G), denoted as b(v,G), is the minimum sum of the communication time required to send a message from v to all vertices in G. The broadcast median problem consists of finding the set of vertices v?V(G) with minimum overall delay b(v,G) and determining the value of b(v,G). In this paper, we consider the broadcast median problem following the heterogeneous postal model. Assuming that the underlying graph G is a general graph, we show that computing b(v,G) for an arbitrary vertex v?V(G) is NP-hard. On the other hand, assuming that G is a tree, we propose a linear time algorithm for the broadcast median problem in heterogeneous postal model.

This paper examines whether an appropriate legal system, which is a combination of a legal regime and a damage apportionment rule, effectively enhances auditor independence. Economic and psychological hypotheses derived from a one-period game model in which the auditor may commit either a technical audit failure (resulting from the auditor’s inability to detect true output given a lack of audit effort) or an independence audit failure (resulting from the auditor’s intentional misreporting on false output) are tested. Three major findings are documented. First, auditor independence affects firm investment, which in turn affects audit effort. Under this strategic dependence, no single legal system can provoke audit effort, improve auditor independence, and encourage firm investment simultaneously. To enhance auditor independence and motivate investment, a legal system consisting of both a strict regime and a proportionate rule is preferred. Second, the strict regime induces more auditor independence than the negligence regime, while the proportionate rule induces higher audit effort than the joint-and-several rule. Finally, auditors’ moral reasoning and penalty for misreporting are both positively associated with their independence. In addition, the effect of moral reasoning on auditor independence diminishes as the level of penalty increases. These two results hold only when the legal systems that auditors face are considered.