3,507 research outputs found
Visual Culture Project: Confederate War Etchings: Searching for Arms by Adalbert Johann Volck
Adalbert Johann Volck’s 1861 sketch of Union soldiers, “Searching for Arms,” represents a substantial contribution to the narrative about gender relations during the American Civil War. This simple, small sketch offers the observer a window into the past. It is a collision of symbols and meaning—from gender to war to the household—all wrapped up in one image. This is a portrait sketch of a woman being invaded in her domestic, private sphere, revealing so much about gender relations during the time. The mistress herself seemed to embody a vast range of sentiments such as anger, fear, frailty, and strength, proving the tension in her role as a wife, a mother, and guardian of the home. This inner conflict is something that all women faced during this time as they strove to remain loyal to the cause for which their husbands fought
The Raman Spectra of CH3CF3 and CCl2CF2
Because of the interest attached to ethane and ethane-like molecules in connection with the question of free rotation of the CX3 groups with respect to each other, it was considered that the Raman spectrum of CH3CF3 might yield additional information on this point. Inasmuch as the spectrum of the liquid can be conveniently photographed only at low temperatures (b.p. about -40°), the determination of the polarization of the scattered light would be experimentally very difficult and was not attempted. The fact that the frequencies associated with the CF3 group will be considerably different in magnitude from those of the CH3 group may, in the analysis, compensate for the lack of data on polarization. Only the results of the experiments are presented here; the assignment of the frequencies will be given when completed. The Raman spectrum of the ethylene-like molecule CCl2=CF2 was photographed at room temperature with the substance in the liquid state, and the observed shifts are presented here
Minimal kernels of Dirac operators along maps
Let be a closed spin manifold and let be a closed manifold. For maps
and Riemannian metrics on and on , we consider
the Dirac operator of the twisted Dirac bundle . To this Dirac operator one can associate an index
in . If is -dimensional, one gets a lower bound for
the dimension of the kernel of out of this index. We investigate
the question whether this lower bound is obtained for generic tupels
Volume and homology of one-cusped hyperbolic 3-manifolds
Let M be a complete, finite-volume, orientable hyperbolic manifold having
exactly one cusp. If we assume that pi_1(M) has no subgroup isomorphic to a
genus-2 surface group, and that either (a) H_1(M;Z_p) has dimension at least 5
for some prime p, or (b) H_1(M;Z_2) has dimension at least 4, and the subspace
of H^2(M;Z_2) spanned by the image of the cup product has dimension at most 1,
then vol M > 5.06 If we assume that H_1(M;Z_2) has dimension at least 7, and
that the compact core of M does not contain a genus-2 closed incompressible
surface, then vol M > 5.06.Comment: 31 pages. This version agrees with the published version of the
paper, except that an error in the published abstract has been corrected. In
particular, the result which applies to manifolds with mod 2 homology of
dimension at least 7 is stronger and has a shorter proof than the
corresponding result in version
On the Validity and Applicability of Models of Negative Capacitance and Implications for MOS Applications
The observation of room temperature sub-60 mV/dec subthreshold slope (SS) in
MOSFETs with ferroelectric (FE) layers in the gate stacks or in series with the
gate has attracted much attention. Recently, we modeled this effect in the
framework of a FE polarization switching model. However, there is a large
amount of literature attributing this effect to a stabilization of quasi-static
(QS) negative capacitance (NC) in the FE. The technological implications of a
stabilized non-switching (NS) QSNC model vs a FE switching model are vastly
different; the latter precluding applications to sub-60 mV/dec SS scaled CMOS
due to speed limitations and power dissipated in switching. In this letter, we
provide a thorough analysis assessing the foundations of models of QSNC,
identifying which specific assumptions (ansatz) may be unlikely or unphysical,
and analyzing their applicability. We show that it is not reasonable to expect
QSNC for two separate capacitors connected in series (with a metal plate
between dielectric (DE) and FE layers). We propose a model clarifying under
which conditions a QS "apparent NC" for a FE layer in a FE-DE bi-layer stack
may be observed, quantifying the requirements of strong interface polarization
coupling in addition to capacitance matching. In this regime, our model
suggests the FE layer does not behave as a NC layer, simply, the coupling leads
to both the DE and FE behaving as high-k DE with similar permittivities. This
may be useful for scaled EOT devices but does not lead to sub-60 mV/dec SS.Comment: Version published in Appl. Phys. Let
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Intra- and Extra-articular Features of Temporomandibular Joint Ankylosis in the Cat (Felis catus).
Temporomandibular joint (TMJ) ankylosis is an uncommon clinical entity in human and veterinary medicine. However, the condition is severely debilitating and is life-limiting if not treated. This study sought to characterize the intra- and extra-articular features of naturally occurring TMJ ankylosis in cats. TMJs from client-owned cats (n = 5) that underwent bilateral TMJ gap arthroplasty were examined and compared with TMJs from healthy, age-matched feline cadavers (n = 2) by cone-beam computed tomography (CBCT), micro-computed tomography (μCT) and histologically. Features of bilateral intra- and extra-articular ankylosis compounded by degenerative joint lesions were identified radiographically and histologically in all affected cats. Features of TMJ 'true' ankylosis included variable intracapsular fibro-osseous bridging, degeneration of the disc and the articular surfaces, narrowing of the joint space and flattening of the condylar process of the mandible. Extra-articular features of TMJ ankylosis included periarticular bone formation and fibro-osseous bridging between the mandible, zygomatic arch and coronoid process. In addition, subchondral bone loss or sclerosis, irregular and altered joint contours and irregularly increased density of the medullary bone characterized the degenerative changes of the osseous components of the TMJ. Complex radiological and histological features of both ankylosis and pseudoankylosis were identified that clinically manifested in complete inability to open the mouth
Spectral and Dynamical Properties in Classes of Sparse Networks with Mesoscopic Inhomogeneities
We study structure, eigenvalue spectra and diffusion dynamics in a wide class
of networks with subgraphs (modules) at mesoscopic scale. The networks are
grown within the model with three parameters controlling the number of modules,
their internal structure as scale-free and correlated subgraphs, and the
topology of connecting network. Within the exhaustive spectral analysis for
both the adjacency matrix and the normalized Laplacian matrix we identify the
spectral properties which characterize the mesoscopic structure of sparse
cyclic graphs and trees. The minimally connected nodes, clustering, and the
average connectivity affect the central part of the spectrum. The number of
distinct modules leads to an extra peak at the lower part of the Laplacian
spectrum in cyclic graphs. Such a peak does not occur in the case of
topologically distinct tree-subgraphs connected on a tree. Whereas the
associated eigenvectors remain localized on the subgraphs both in trees and
cyclic graphs. We also find a characteristic pattern of periodic localization
along the chains on the tree for the eigenvector components associated with the
largest eigenvalue equal 2 of the Laplacian. We corroborate the results with
simulations of the random walk on several types of networks. Our results for
the distribution of return-time of the walk to the origin (autocorrelator)
agree well with recent analytical solution for trees, and it appear to be
independent on their mesoscopic and global structure. For the cyclic graphs we
find new results with twice larger stretching exponent of the tail of the
distribution, which is virtually independent on the size of cycles. The
modularity and clustering contribute to a power-law decay at short return
times
The political economy of financing children's rights through extractive industries in the Philippines
The surging investments in the extractive industries (EI) that began in the 1980s, as well as the commodity boom between 2002 and 2011, have increased the significance of the sector in national economic development. This paper takes the Philippines as a case study and provides a detailed analysis of two key aspects of mining governance: first, the political challenges in realizing a more positive role for EI in social development, particularly in promoting children´s rights and children´s welfare, and second, the political economy dynamics that might underpin the creation of a welfare regime able to sustain social investments for children. The findings of this paper suggest that in the Philippine context, where the expansion of the EI sector is contested in the public domain, the link between mining governance and the promotion and protection of children´s rights is not necessarily straightforward. Yet equally, the resurgence of high prices and the continuing interest of foreign investment in EI means that there is now a political opportunity for relevant stakeholders to make a compelling argument for the need to ring-fence mineral rents for social investments in children and young people. To do so would require a strong pro-welfare policy coalition committed to channelling mineral wealth towards social investment and willing to craft a political consensus through negotiations between local and national elites, donor agencies, civil society organizations and affected local communities. Importantly, the state must also wrestle with multinational capital, large Filipino-owned companies and small-scale miners in the process of negotiating reforms. Ultimately, the state must seize this opportunity to take a more active role in laying the foundations of a mining governance framework, bargain with key stakeholders to reach agreement on EI-funded welfare and set out rights-based approaches to development. This paper builds on a selective qualitative data collection from a variety of printed sources, including donor agency reports, government documents, NGO reports, newspaper archives, and interviews available online. It further builds on a short fieldwork period in Manila, in late August 2013, where key sources from civil society, academia, the extractive industry, the donor community and stakeholders were interviewed
The diameter of the set of boundary slopes of a knot
Let K be a tame knot with irreducible exterior M(K) in a closed, connected,
orientable 3--manifold Sigma such that pi_1(Sigma) is cyclic. If infinity is
not a strict boundary slope, then the diameter of the set of strict boundary
slopes of K, denoted d_K, is a numerical invariant of K. We show that either
(i) d_K >= 2 or (ii) K is a generalized iterated torus knot. The proof combines
results from Culler and Shalen [Comment. Math. Helv. 74 (1999) 530-547] with a
result about the effect of cabling on boundary slopes.Comment: This is the version published by Algebraic & Geometric Topology on 29
August 200
More Torsion in the Homology of the Matching Complex
A matching on a set is a collection of pairwise disjoint subsets of
of size two. Using computers, we analyze the integral homology of the matching
complex , which is the simplicial complex of matchings on the set . The main result is the detection of elements of order in the
homology for . Specifically, we show that there are
elements of order 5 in the homology of for and for . The only previously known value was , and in this particular
case we have a new computer-free proof. Moreover, we show that there are
elements of order 7 in the homology of for all odd between 23 and 41
and for . In addition, there are elements of order 11 in the homology of
and elements of order 13 in the homology of . Finally, we
compute the ranks of the Sylow 3- and 5-subgroups of the torsion part of
for ; a complete description of the homology
already exists for . To prove the results, we use a
representation-theoretic approach, examining subcomplexes of the chain complex
of obtained by letting certain groups act on the chain complex.Comment: 35 pages, 10 figure
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