To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure email@example.com
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS) is a powerful technique for the study of biogeochemical cycling of a variety of metals. The advantages of this technique include high ionization efficiency, low detection limits, and rapid analysis. It can produce highly precise and accurate elemental isotope compositions of natural and experimental samples, which can provide insights into the mechanisms of both biological and abiological processes in in natural environments. In this chapter, the operating principles of the instrument, purification of samples, interferences encountered, correction methods to eliminate the instrumental mass discrimination, and data analysis with respect to reliability and reproducibility are discussed. A case study is included that highlights the capability of MC-ICP-MS to infer mechanisms of Fe redox processes in an acidic oligotrophic lake using natural abundance of stable Fe isotopes.
Concerns over food safety in China not only direct public attention to negative
incidents, but also trigger the government's scrutiny of implicated
firms, particularly MNCs. The question of how to repair legitimacy after media
coverage of negative incidents has become a critical issue for MNCs. Although
the factors for MNCs’ public crises have been identified, how local
contexts and mechanisms shape repair approaches remain unclear. To address this
research gap, we conducted a study of Walmart China's approaches
associated with two negative incidents across two regions. We found that the
negative incidents can be framed differently depending on the local
environment's unfavorability for MNCs. Specifically, the negative
framing gave rise to varying degrees of legitimacy loss and offered different
leeway for MNCs to repair their legitimacy. We also identified the varied
outcomes of different repair approaches. By revealing the linkages among local
context, framing, legitimacy repair, and its outcomes, our study contributes to
research on MNCs’ legitimacy management under institutional
complexity and underscores the China context for legitimacy maintenance. We also
offer insights that advance the institutional approach to legitimacy repair in
this context. Last, we reflect on the techniques for conducting qualitative
research in China.
Some amino acids (AA) act through several signalling pathways and mechanisms to mediate the control of gene expression at the translation level, and the regulation occurs, specifically, on the initiation and the signalling pathways for translation. The translation of mRNA to protein synthesis proceeds through the steps of initiation and elongation, and AA act as important feed-forward activators that are involved in many pathways, such as the sensing and the transportation of AA by cells, in these steps in many tissues of mammals. For the translation, phosphorylation of eukaryotic translation initiation factor 2α (eIF2α) is a critical molecule that controls the translation initiation and its functions can be regulated by some AA. Another control point in the mRNA binding step in the translation initiation is at the regulation by mammalian target of rapamycin, which requires a change of phosphorylation status of ribosomal protein S6. In fact, the change of phosphorylation status of ribosomal protein S6 might be involved in global protein synthesis. The present review summarises recent work on the molecular mechanisms of the regulation of protein synthesis by AA and highlights new findings.
The stability of stochastic differential equations in abstract, mainly Hilbert, spaces receives a unified treatment in this self-contained book. It covers basic theory as well as computational techniques for handling the stochastic stability of systems from mathematical, physical and biological problems. Its core material is divided into three parts devoted respectively to the stochastic stability of linear systems, non-linear systems, and time-delay systems. The focus is on stability of stochastic dynamical processes affected by white noise, which are described by partial differential equations such as the Navier–Stokes equations. A range of mathematicians and scientists, including those involved in numerical computation, will find this book useful. It is also ideal for engineers working on stochastic systems and their control, and researchers in mathematical physics or biology.
We give some sufficient conditions for the periodicity of entire functions based on a conjecture of C. C. Yang, using the concepts of value sharing, unique polynomial of entire functions and Picard exceptional value.
We hypothesize that the tumor necrosis factor-α (TNF-α) may play a role in disturbing the effect of selective serotonin reuptake inhibitor (SSRI) on the striatal connectivity in patients with major depressive disorder (MDD).
We performed a longitudinal observation by combining resting-state functional magnetic resonance imaging (rs-fMRI) and biochemical analyses to identify the abnormal striatal connectivity in MDD patients, and to evaluate the effect of TNF-α level on these abnormal connectivities during SSRI treatment. Eighty-five rs-fMRI scans were collected from 25 MDD patients and 35 healthy controls, and the scans were repeated for all the patients before and after a 6-week SSRI treatment. Whole-brain voxel-wise functional connectivity (FC) was calculated by correlating the rs-fMRI time courses between each voxel and the striatal seeds (i.e. spherical regions placed at the striatums). The level of TNF-α in serum was evaluated by Milliplex assay. Factorial analysis was performed to assess the interaction effects of ‘TNF-α × treatment’ in the regions with between-group FC difference.
Compared with controls, MDD patients showed significantly higher striatal FC in the medial prefrontal cortex (MPFC) and bilateral middle/superior temporal cortices before SSRI treatment (p < 0.001, uncorrected). Moreover, a significant interaction effect of ‘TNF-α × treatment’ was found in MPFC-striatum FC in MDD patients (p = 0.002), and the significance remained after adjusted for age, gender, head motion, and episode of disease.
These findings provide evidence that treatment-related brain connectivity change is dependent on the TNF-α level in MDD patients, and the MPFC-striatum connectivities possibly serve as an important target in the brain.
Triple homomorphisms on C*-algebras and JB*-triples have been studied in the literature. From the viewpoint of associative algebras, we characterise the structure of triple homomorphisms from an arbitrary ⋆-algebra onto a prime *-algebra. As an application, we prove that every triple homomorphism from a Banach ⋆-algebra onto a prime semisimple idempotent Banach *-algebra is continuous. The analogous results for prime C*-algebras and standard operator *-algebras on Hilbert spaces are also described.
A Pneumatic Muscle Actuator (PMA) is a new pneumatic component sharing similar characteristics with biological muscles, and the flexible manipulator actuated by PMAs can better reflect the flexibility of the mechanism. First and foremost, based on the study of the characteristics of human shoulder joints, the configuration design of the flexible manipulator is analyzed, and its kinematics and dynamics models are established. Furthermore, with regard to the nonlinearity, time-invariance and uncertainty of the control system, three aspects of improvement are proposed, which are based on the Radial Basis Function (RBF) network torque control algorithm. The Genetic Algorithm is used to optimize the initial values of RBF network parameters; RBF network parameters are adjusted dynamically by using the additional momentum method; the Levenberg--Marquardt (LM) algorithm, instead of the gradient descent method, is adopted to adjust Proportion Integration Differentiation (PID) parameters online in real time. At last, to test the effects that the improved algorithm exerts on the flexible manipulator control system, some physical platform experiments are carried out. It turns out that the control accuracy and robustness of the improved algorithm are well improved, and the mechanism can be controlled better to track the circular arc trajectory. It lays fundamental importance to the practical application for the working environment.