The R&D boundaries of the firm : a problem solving perspective

This paper considers, theoretically and empirically, how different organization modes are aligned to govern the efficient solving of technological problems. The data set is from the Chinese consumer electronics industry. Following the problem solving perspective (PSP) within the knowledge-based view (KBV), we develop and test several PSP and KBV hypotheses, whilst controlling for some relevant transaction cost economics (TCE) and other variables, in an examination of the determinants of the firms’ R&D organization choice. The results show that a firm’s existing knowledge base is the most important explanatory factor. Problem complexity and decomposability are also found to be important, but it is suggested, contrary to the view of PSP, that they are better treated as separate variables, and that equity-based alliances tend to be reserved for the most complex problems

Breakpoint lead-lag analysis of the last deglacial climate change and atmospheric CO2 concentration on global and hemispheric scales

Antarctic ice core records show that climate change and atmospheric CO2 concentration (aCO(2)) are closely related over the past 800 thousand years. However, the interpretation of their sequential, and hence the causal relationship has long been controversial. In this study, we revisit this long-standing scientific issue based on 88 well-dated high-resolution climate proxy records derived from ice cores, marine deposits, and stalagmites. We composite global and hemispheric stacks of the last deglacial climate index (DCI) using a normalization scheme instead of a more conventional area-weighting and mixing scheme to enable a better detection of temporal variations. Rampfit and Breakfit techniques are employed to detect the trend transitions in each composited DCI series and in the recently constructed centennial-scale aCO(2) over the period from 22 to 9 thousand years before present. We detect a clear lead of DCI change over aCO(2) variation on both global and hemispheric scales at the early stage of the deglaciation, suggesting that the variation of aCO(2) is an internal feedback in Earth's climate system rather than an initial trigger of the last deglacial warming. During the periods of the Bolling-Allerod and the Younger Dryas, the climate system appeared to have been constrained by a fast coupling mechanism between climate change and aCO(2) with no obvious asynchrony. The northern and southern hemispheric DCI stacks exhibit a seesawing pattern that can be linked to the influences of Atlantic meridional overturning circulation (AMOC) strength, revealing an important role of AMOC in regulating the global climate in the course of the last deglaciation

Breakpoint lead-lag analysis of the last deglacial climate change andatmospheric CO2 concentration on global and hemispheric scales

Antarctic ice core records show that climate change and atmospheric CO2 concentration (aCO2) are closely related over the past 800 thousand years. However, the interpretation of their sequential, and hence the causal relationship has long been controversial. In this study, we revisit this long-standing scientific issue based on 88 well-dated high-resolution climate proxy records derived from ice cores, marine deposits, and stalagmites. We composite global and hemispheric stacks of the last deglacial climate index (DCI) using a normalization scheme instead of a more conventional area-weighting and mixing scheme to enable a better detection of temporal variations. Rampfit and Breakfit techniques are employed to detect the trend transitions in each composited DCI series and in the recently constructed centennial-scale aCO2 over the period from 22 to 9 thousand years before present. We detect a clear lead of DCI change over aCO2 variation on both global and hemispheric scales at the early stage of the deglaciation, suggesting that the variation of aCO2 is an internal feedback in Earth&#39;s climate system rather than an initial trigger of the last deglacial warming. During the periods of the B&oslash;lling-Aller&oslash;d and the Younger Dryas, the climate system appeared to have been constrained by a fast coupling mechanism between climate change and aCO2 with no obvious asynchrony. The northern and southern hemispheric DCI stacks exhibit a seesawing pattern that can be linked to the influences of Atlantic meridional overturning circulation (AMOC) strength, revealing an important role of AMOC in regulating the global climate in the course of the last deglaciation.<br /

Contemporary crustal kinematics in the Guangdong-Hong Kong-Macao Greater Bay Area, SE China: Implications for the geothermal resource exploration

Fault kinematics plays an important role in estimating the stress state and permeability of faults which are controlling factors in the formation of a geothermal system. However, there are very few studies on the kinematic characteristics of the major faults in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA), SE China. To obtain a better understanding of the fault kinematics, we establish a comprehensive 3D geomechanical model for the GBA. Our results show that the NE-trending faults in the west of the Pearl River Estuary (PRE) usually slip faster than the faults striking in the ENE-WSW direction to the east of the PRE. The NW-trending faults have the lowest modeled fault slip rate. Slip rates of the faults are generally low with a maximum value of 0.12 mm/a occurring on the northeastern segment of the Wuchuan-Sihui fault. The NE-trending faults display sinistral motion, while the ENE-trending faults are dextral. The opposite slip senses on these two fault groups are inferred to be caused by the lateral variations in the crustal stress. Based on the analysis of contemporary kinematics and the heat flow in the GBA, we suggest that the fault segments with relatively high slip rates, such as the northeastern segment of the Wuchuan-Sihui fault, the Kaiping fault, the Enping fault, and the middle segments of the Wuhua-Shenzhen, Zijin-Boluo, and Heyuan faults, have a high prospect for geothermal resources. The intersections of the NW-trending extensional faults and the NE-/ENE-trending faults could also be potential areas of interest for future geothermal exploration

Unsupervised Gait Recognition with Selective Fusion

Previous gait recognition methods primarily trained on labeled datasets, which require painful labeling effort. However, using a pre-trained model on a new dataset without fine-tuning can lead to significant performance degradation. So to make the pre-trained gait recognition model able to be fine-tuned on unlabeled datasets, we propose a new task: Unsupervised Gait Recognition (UGR). We introduce a new cluster-based baseline to solve UGR with cluster-level contrastive learning. But we further find more challenges this task meets. First, sequences of the same person in different clothes tend to cluster separately due to the significant appearance changes. Second, sequences taken from 0{\deg} and 180{\deg} views lack walking postures and do not cluster with sequences taken from other views. To address these challenges, we propose a Selective Fusion method, which includes Selective Cluster Fusion (SCF) and Selective Sample Fusion (SSF). With SCF, we merge matched clusters of the same person wearing different clothes by updating the cluster-level memory bank with a multi-cluster update strategy. And in SSF, we merge sequences taken from front/back views gradually with curriculum learning. Extensive experiments show the effectiveness of our method in improving the rank-1 accuracy in walking with different coats condition and front/back views conditions

Growth of Wide-Bandgap Monolayer Molybdenum Disulfide for a Highly Sensitive Micro-Displacement Sensor

Two-dimensional (2D) piezoelectric semiconductor materials are garnering significant attention in applications such as intelligent sensing and energy harvesting due to their exceptional physical and chemical properties. Among these, molybdenum disulfide (MoS2), a 2D wide-bandgap semiconductor, exhibits piezoelectricity in odd-layered structures due to the absence of an inversion symmetry center. In this study, we present a straightforward chemical vapor deposition (CVD) technique to synthesize monolayer MoS2 on a Si/SiO2 substrate, achieving a lateral size of approximately 50 µm. Second-harmonic generation (SHG) characterization confirms the non-centrosymmetric crystal structure of the wide-bandgap MoS2, indicative of its piezoelectric properties. We successfully transferred the triangular MoS2 to a polyethylene terephthalate (PET) flexible substrate using a wet-transfer method and developed a wide-bandgap MoS2-based micro-displacement sensor employing maskless lithography and hot evaporation techniques. Our testing revealed a piezoelectric response current of 5.12 nA in the sensor under a strain of 0.003% along the armchair direction of the monolayer MoS2. Furthermore, the sensor exhibited a near-linear relationship between the piezoelectric response current and the strain within a displacement range of 40–100 µm, with a calculated response sensitivity of 1.154 µA/%. This research introduces a novel micro-displacement sensor, offering potential for advanced surface texture sensing in various applications

Continental heat gain in the global climate system

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95084/1/grl15494.pd

Effects of Simvastatin on Glucose Metabolism in Mouse MIN6 Cells

The aim of this study was to investigate the effects of simvastatin on insulin secretion in mouse MIN6 cells and the possible mechanism. MIN6 cells were, respectively, treated with 0 μM, 2 μM, 5 μM, and 10 μM simvastatin for 48 h. Radio immunoassay was performed to measure the effect of simvastatin on insulin secretion in MIN6 cells. Luciferase method was used to examine the content of ATP in MIN6 cells. Real-time PCR and western blotting were performed to measure the mRNA and protein levels of inward rectifier potassium channel 6.2 (Kir6.2), voltage-dependent calcium channel 1.2 (Cav1.2), and glucose transporter-2 (GLUT2), respectively. ATP-sensitive potassium current and L-type calcium current were recorded by whole-cell patch-clamp technique. The results showed that high concentrations of simvastatin (5 μM and 10 μM) significantly reduced the synthesis and secretion of insulin compared to control groups in MIN6 cells (P<0.05). ATP content in simvastatin-treated cells was lower than in control cells (P<0.05). Compared with control group, the mRNA and protein expression of Kir6.2 increased with treatment of simvastatin (P<0.05), and mRNA and protein expression of Cav1.2 and GLUT2 decreased in response to simvastatin (P<0.05). Moreover, simvastatin increased the ATP-sensitive potassium current and reduced the L-type calcium current. These results suggest that simvastatin inhibits the synthesis and secretion of insulin through a reduction in saccharometabolism in MIN6 cells