10,000 publications from this institution
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
In streams where algivorous fishes abound, striking variation of attached algae often develops along depth gradients, with bands of high standing crops in shallow water (<20 cm) and sparse standing crops on deeper substrates. Experimental results from a stream in central Panama support the hypothesis that vertical variation in algal standing crops arises when grazing fishes avoid predators in shallow water by forgoing food resources that accumulate there. When 38 rocks bearing algae in a stream in central Panama were transferred from shallow (<20 cm) to deeper (>20 cm) water, algae were rapidly consumed by grazing catfish. Catfish were removed from three stream pools and left in place in three control pools. Ten days after catfish removal, algal standing crops in deep and shallow areas of removal pools were similar, while algal standing crops were higher in shallow than in deep areas of control pools. Catfish were exposed to fishing birds in open-topped enclosures. In one of three series of these pens, most catfish in shallow pens (10 and 20 cm) disappeared after 14 days, while catfish in deeper pens (30 and 50 cm) did not. Other groups of catfish which were caged 8 days showed differences in behavior depending on whether they had been fed or starved. After their release into their home pool, starved catfish spent more time feeding than did fed catfish. Despite their apparently increased hunger levels, starved catfish did not venture into shallow water to obtain algae. These results support the view that predator induced avoidance by grazers of certain areas can produce spatial pattern in the flora of flowing water communities. © 1989 Kluwer Academic Publishers.
Abstract The use of electrochemical impedance spectroscopy (EIS) in corrosion research is briefly reviewed with particular emphasis on the advantages offered by this technique over other electrochemical methods. These advantages include the fact that it is a steady state technique, that it employs small signal analysis, and that is capable of probing relaxations over a very wide frequency rate (<1 mHz to >1 MHz) using readily available instrumentation. EIS also has the enormous advantage over classical transient techniques in that the validity of the data is readily checked using the Kramers-Kronig transforms. The principal pitfall of the method is the tendency of many workers to analyze their data in terms of simple equivalent electrical circuits, and hence to ignore the great power of EIS for deriving mechanistic and kinetic information for processes that occur at a corroding interface.
We present a distributed representation of pose and appearance of people called the "poselet activation vector". First we show that this representation can be used to estimate the pose of people defined by the 3D orientations of the head and torso in the challenging PASCAL VOC 2010 person detection dataset. Our method is robust to clutter, aspect and viewpoint variation and works even when body parts like faces and limbs are occluded or hard to localize. We combine this representation with other sources of information like interaction with objects and other people in the image and use it for action recognition. We report competitive results on the PASCAL VOC 2010 static image action classification challenge.
We describe an inverse electromagnetic design algorithm to design computer generated holograms in the full-wave domain, with a finite-difference time-domain solver. The algorithm searches for an optimal binary hologram design with the adjoint gradient method.
Organotransition metal complexes catalyze important synthetic transformations, and the development of these systems has rested on the detailed understanding of the structures and elementary reactions of discrete organometallic complexes bound to organic ligands. One strategy for the creation of new organometallic systems is to exploit the intricate and highly structured ligands found in natural metalloproteins. We report the preparation and characterization of discrete rhodium and iridium fragments bound site-specifically in a κ(2)-fashion to the protein carbonic anhydrase as a ligand. The reactions of apo human carbonic anhydrase with [Rh(nbd)2]BF4 or [M(CO)2(acac)] (M=Rh, Ir) form proteins containing Rh or Ir with organometallic ligands. A colorimetric assay was developed to quantify rapidly the metal occupancy at the native metal-binding site, and (15)N-(1)H NMR spectroscopy was used to establish the amino acids to which the metal is bound. IR spectroscopy and EXAFS revealed the presence and number of carbonyl ligands and the number total ligands, while UV-vis spectroscopy provided a signature to readily identify species that had been fully characterized. Exploiting these methods, we observed fundamental stoichiometric reactions of the artificial organometallic site of this protein, including reactions that simultaneously form and cleave metal-carbon bonds. The preparation and reactivity of these artificial organometallic proteins demonstrate the potential to study a new genre of organometallic complexes for which the rates and outcomes of organometallic reactions can be controlled by genetic manipulation of the protein scaffold.
ABSTRACT Objective Proinflammatory cytokines are associated with bipolar disorder (BD), but less is known about how cytokines function during the interepisode period. This study examined cytokines, mood symptoms, and sleep in individuals with interepisode BD with complaints of insomnia. We also investigated the effects of a BD-specific modification of cognitive behavior therapy for insomnia (CBTI-BP) on cytokine levels. Methods Twenty-two adults with interepisode BD type I and insomnia were drawn from a subset of a National Institute of Mental Health funded study. Participants were randomly allocated to CBTI-BP ( n = 11) or psychoeducation ( n = 11). Participants completed a sleep diary, rated self-report measures of mania and depression, and provided samples assayed for interleukin (IL)-6 and tumor necrosis factor soluble receptor 2 (sTNF-R2). Results IL-6 was associated with mania symptoms ( r s = 0.44, p = .041) and total sleep time ( r s = −0.49, p = .026). IL-6 was related to depression symptoms at the trend level ( r s = 0.43, p = .052). sTNF-R2 was not significantly related to mood or sleep measures. From pretreatment to posttreatment, CBTI-BP compared with psychoeducation was associated with a nonsignificant, large effect size decrease in IL-6 ( z = −1.61, p = .13, d = −0.78) and a nonsignificant, small-medium effect size decrease in sTNF-R2 ( z = −0.79, p = .44, d = −0.38). Conclusions These findings provide preliminary evidence that IL-6 is related to mania symptoms and shorter total sleep time in interepisode BD. A treatment that targets sleep in BD could potentially decrease IL-6 although replication is warranted.
This work presents a new approach to unsupervised abstractive summarization\nbased on maximizing a combination of coverage and fluency for a given length\nconstraint. It introduces a novel method that encourages the inclusion of key\nterms from the original document into the summary: key terms are masked out of\nthe original document and must be filled in by a coverage model using the\ncurrent generated summary. A novel unsupervised training procedure leverages\nthis coverage model along with a fluency model to generate and score summaries.\nWhen tested on popular news summarization datasets, the method outperforms\nprevious unsupervised methods by more than 2 R-1 points, and approaches results\nof competitive supervised methods. Our model attains higher levels of\nabstraction with copied passages roughly two times shorter than prior work, and\nlearns to compress and merge sentences without supervision.\n
