Stone weirs on Chipei Island, Taiwan--Landesque capital and ecologically unequal exchange

This thesis focuses on the development of stone weirs on Chipei Island. Chipei is one of the offshore islands of the Penghu archipelago in Taiwan. Stone weirs on Chipei Island have been in use for more than three centuries. The islanders developed a social structure based on building and utilizing stone weirs for fishing. Stone weirs are central to the legacies of every family on Chipei. Nowadays, most people still hold shares in stone weirs. The development of stone weirs on Chipei Island is examined from the perspective of historical-political ecology, more specifically drawing on the concepts of landesque capital and ecologically unequal exchange. Three phases were carried out in the use of stone weirs, 1) pre-1940s, stone weir as landesque capital, when the KMT took over 2) from the end of the 1940s to the 1970s ecologically unequal exchange occurred in the stone weirs and Chipei Island 3) from post-1970s, tourist industry became the most important sector that stone weirs become a destination of tourists

Modal Verbs for the Advice Move in Advice Columns

PACLIC 23 / City University of Hong Kong / 3-5 December 200

Atmospheric chemistry-climate feedbacks

We extend the theory of climate feedbacks to include atmospheric chemistry. A change in temperature caused by a radiative forcing will include, in general, a contribution from the chemical change that is fed back into the climate system; likewise, the change in atmospheric burdens caused by a chemical forcing will include a contribution from the associated climate change that is fed back into the chemical system. The theory includes two feedback gains, G_(che) and G_(cli). G_(che) is defined as the ratio of the change in equilibrium global mean temperature owing to long-lived greenhouse gas radiative forcing, under full climate-chemistry coupling, to that in the absence of coupling. G_(cli) is defined as the ratio of the change in equilibrium mean aerosol or gas-phase burdens owing to chemical forcing under full coupling, to that in the absence of coupling. We employ a climate-atmospheric chemistry model based on the Goddard Institute for Space Studies (GISS) GCM II', including tropospheric gas-phase chemistry, sulfate, nitrate, ammonium, black carbon, and organic carbon. While the model describes many essential couplings between climate and atmospheric chemistry, not all couplings are accounted for, such as indirect aerosol forcing and the role of natural dust and sea salt aerosols. Guided by the feedback theory, we perform perturbation experiments to quantify G_(che) and G_(cli). We find that G_(che) for surface air temperature is essentially equal to 1.00 on a planetary scale. Regionally, G_(che) is estimated to be 0.80–1.30. The gains are small compared to those of the physical feedbacks in the climate system (e.g., water vapor, and cloud feedbacks). These values for G_(che) are robust for the specific model used, but may change when using more comprehensive climate-atmospheric chemistry models. Our perturbation experiments do not allow one to obtain robust values for G_(cli). Globally averaged, the values range from 0.99 to 1.28, depending on the chemical species, while, in areas of high pollution, G_(cli) can be up to 1.15 for ozone, and as large as 1.40 for total aerosol. These preliminary values indicate a significant role of climate feedbacks in the atmospheric chemistry system

Multiferroic and Ferroic Topological Order in Ligand-Functionalized Germanene and Arsenene

Two-dimensional (2D) materials that exhibit ferroelectric, ferromagnetic, or topological order have been a major focal topic of nanomaterials research in recent years. The latest efforts in this field explore 2D quantum materials that host multiferroic or concurrent ferroic and topological order. We present a computational discovery of multiferroic state with coexisting ferroelectric and ferromagnetic order in recently synthesized CH2OCH3-functionalized germanene. We show that an electric-field-induced rotation of the ligand CH2OCH3 molecule can serve as the driving mechanism to switch the electric polarization of the ligand molecule, while unpassivated Ge p(z) orbits generate ferromagnetism. Our study also reveals coexisting ferroelectric and topological order in ligand-functionalized arsenene, which possesses a switchable electric polarization and a Dirac transport channel. These findings offer insights into the fundamental physics underlying these coexisting quantum orders and open avenues for achieving states of matter with multiferroic or ferroic-topological order in 2D-layered materials for innovative memory or logic device implementations

Investigating the Effects of TBDF Regulations on Multinational Firms\u27 Operation

The far advance in computer and telecommunication technology, and the evolution of Multinational corporations (MNCs) have led to an era of global economy. While MNCs strive for competitive advantage via their global information systems, diverse barriers on transborder data flow (TBDF) work in the opposite direction. Many researchers indicated that TBDF restrictions not only affected the operation of MNCs, but also the management of international information systems. Some others argued that transborder data laws were either found too vague to follow, or unable to seriously hamper some MNCs due to their smooth relationship with local telecommunication authorities at host countries. This paper aims to investigate the context and causes of the discrepancy. The results indicated that vendor’ s support, deregulation of telecommunication restrictions, and the areas in which MNCs operated accounted for the discrepancy and thus alleviated the impact of TBDF regulations on MNCs\u27 operation

Geometric sharp large deviations for random projections of ℓpn\ell_p^n spheres

Estimation of tail probabilities of projections of high-dimensional probability measures is of relevance in high-dimensional statistics and asymptotic geometric analysis. For fixed $p \in (1,\infty)$, let $(X^{(n,p)})_{n \in \mathbb{N}}$ and $(\theta^n)_{n \in \mathbb{N}}$ be independent sequences of random vectors with $\theta^n$ distributed according to the normalized cone measure on the unit $\ell_2^n$ sphere, and $X^{(n,p)}$ distributed according to the normalized cone measure on the unit $\ell_p^n$ sphere. For almost every sequence of projection directions $(\theta^n)_{n \in \mathbb{N}}$, (quenched) sharp large deviation estimates are established for suitably normalized (scalar) projections of $X^{(n,p)}$ onto $\theta^n$, that are asymptotically exact (as the dimension $n$ tends to infinity). In contrast to the (quenched) large deviation rate function, the prefactor exhibits a dependence on the projection directions $(\theta^n)_{n \in\mathbb{N}}$ that encodes geometric information. Moreover, comparison with numerical estimates obtained by direct computation and importance sampling shows that the obtained analytical expressions for tail probabilities provide good approximations even for moderate values of $n$. The results on the one hand provide more accurate quantitative estimates of tail probabilities of random projections of $\ell_p^n$ spheres than logarithmic asymptotics, and on the other hand, generalize classical sharp large deviation estimates in the spirit of Bahadur and Ranga Rao to a geometric setting. The proofs combine Fourier analytic and probabilistic techniques, rely on a simpler representation for the quenched large deviation rate function that shows that it is strictly convex, and entail establishing central limit theorems for random projections under a certain family of tilted measures, which may be of independent interest.Comment: 38 pages. This version of the paper is a slightly modified version of v1, with more details added to the proofs of Proposition 5.4 for greater clarity. The additional analysis of $\ell^n_p$ balls (some of which was carried out in v2), along with other thematically connected generalizations, are relegated to a forthcoming pape

Beyond the single-atom response in absorption lineshapes: Probing a dense, laser-dressed helium gas with attosecond pulse trains

We investigate the absorption line shapes of laser-dressed atoms beyond the single-atom response, by using extreme ultraviolet (XUV) attosecond pulse trains to probe an optically thick helium target under the influence of a strong infrared (IR) field. We study the interplay between the IR-induced phase shift of the microscopic time-dependent dipole moment and the resonant-propagation-induced reshaping of the macroscopic XUV pulse. Our experimental and theoretical results show that as the optical depth increases, this interplay leads initially to a broadening of the IR-modified line shape, and subsequently to the appearance of new, narrow features in the absorption line.Comment: 5 pages, 5 figure

Neutral silicon interstitials in silicon carbide: a first principles study

International audienceAbstract. The structures and stability of single silicon interstitials in their neutral state are investigated via first principles calculations in 3C- and 4H-SiC. By carefully checking the convergence with Brillouin Zone (BZ) sampling and supercell size we explain the disagreement between previous published results and we show that the split interstitial along direction and tetrahedrally carbon coordinated structure have similar formation energies in the cubic polytype. A new migration mechanism for the silicon interstitial in the neutral state is presented here which could be important for the evolution of defect populations in SiC. For 4H-SiC, the most energetically favourable silicon interstitial is found to be the split interstitial configuration ISisp but situated in the hexagonal layer. The defect formation energies in 4H-SiC are in general larger than those in 3C-SiC, implying that the insertion of silicon interstitial introduces a large lattice distortion to the local coordination environments and affect even the second- or third-nearest neighbours. We also present a comparison between well converged plane waves calculations and calculations with three localized orbital basis sets; one of them, in spite of providing a reasonable description for bulk properties, is clearly not suitable to describe interstitial defects