Search

The excited-state dynamics of a spiro-fused terrylene-3,4:11,12-bis(dicarboximide) (TDI) dimer (sTDI2) in toluene and 2-methyltetrahydrofuran (mTHF) were investigated as a function of temperature using femtosecond- and nanosecond-transient absorption spectroscopy, as well as two-dimensional electronic spectroscopy. The spiro conjugation and the corresponding geometry of this compound guarantee a short intermonomer distance along with a partial orbital overlap between the orthogonal TDI π-electron systems, providing electronic coupling between the TDIs. Photoexcitation of sTDI2 in toluene, a low dielectric solvent, at 295 K, results in the ultrafast formation of a state composed of a coherent mixture of singlet 1(S1S0), multiexciton 1(T1T1), and charge-transfer (CT) electronic characters. This mixed species decays to decorrelated triplet states on the nanosecond timescale, completing the process of intramolecular singlet fission (SF) in sTDI2. Upon decreasing the temperature from 295 to 200 K, the contribution of the 1(T1T1) state to the mixed species decreases concurrently with an increase in the CT state character. We attribute this behavior to the variation in the vibrational energy level alignment between the states comprising the mixture due to changes in the temperature and hence the local dielectric environment. In contrast, photoexcitation of sTDI2 in more polar mTHF at 295 K results in the formation of a mixed singlet and CT state before undergoing symmetry-breaking charge separation, owing to the increased stabilization of the CT state in the medium. However, in glassy mTHF at 85 K, photoexcited sTDI2 exhibits discernible multiexciton character, comparable to that observed in toluene at 200 K, which we rationalize by the similarity of the dielectric constants under these two sets of conditions. These observations of mixed states of varying diabatic contributions over the range of experimental conditions show that the temperature and the static dielectric constant can directly control the composition of the electronically mixed excited state of sTDI2 and thus the fate of the SF process.

The caddisfly Hydroptila lotensis Mosely, 1930, (Trichoptera: Hydroptilidae) is added to the Irish list based on males and females collected on the River Liffey, Co. Kildare, in the east of Ireland. In addition, males and females of the caddisfly Hydroptila vectis Curtis, 1834, were taken on the River Dodder in Dublin City. This species was previously only known from Co. Donegal in north-west Ireland.

Singlet fission (SF) is a photophysical process capable of boosting the efficiency of solar cells. Recent experimental investigations into the mechanism of SF provide evidence for coherent mixing between the singlet, triplet, and charge transfer basis states. Up until now, this interpretation has largely focused on electronic interactions; however, nuclear motions resulting in vibronic coupling have been suggested to support rapid and efficient SF in organic chromophore assemblies. Further information about the complex interactions between vibronic excited states is needed to understand the potential role of this coupling in SF. Here, we report mixed singlet and correlated triplet pair states giving rise to sub-50 fs SF in a terrylene-3,4:11,12-bis(dicarboximide) (TDI) dimer in which the two TDI molecules are covalently linked by a direct N-N connection at one of their imide positions, leading to a linear dimer with perpendicular TDI π systems. We observe the transfer of low-frequency coherent wavepackets between the initial predominantly singlet states to the product triplet-dominated states. This implies a non-negligible dependence of SF on nonadiabatic coupling in this dimer. We interpret our experimental results in the framework of a modified Holstein Hamiltonian, which predicts that vibronic interactions between low-frequency singlet modes and high-frequency correlated triplet pair motions lead to mixing of the pure basis states. These results highlight how nonadiabatic mixing can shape the complex potential energy landscape underlying ultrafast SF.

The discovery of the caddisfly Limnephilus borealis at a second site in Northern Ireland strongly suggests that the species is an established native. Within the British Isles L. borealis was previously known only from Scotland.

The reaction between acetylenedicarboxylic acid and 4-benzylpyridine yields two products: a salt and a zwitterion. The relationship between these two products has been investigated, revealing that the salt is the kinetic product of the reaction and the zwitterion is the thermodynamic product. The zwitterion has four polymorphs and three solvates. Interconversion between these forms has been studied and was shown to be solvent-mediated when it occurs; conversion between most polymorphic forms cannot be achieved using thermal methods. The temperature at which the reaction to form the zwitterion is carried out and the solvent system used are crucial in determining which polymorphic form crystallizes from the reaction. In addition, polymorphic Form I is shown to be porous to dioxane.

Grain sorghum is a potential feedstock for fuel ethanol production due to its high starch content, which is equivalent to that of corn, and has been successfully used in several commercial corn ethanol plants in the United States. Some sorghum grain varieties contain significant levels of surface wax, which may interact with enzymes and make them less efficient toward starch hydrolysis. On the other hand, wax can be recovered as a valuable co-product and as such may help improve the overall process economics. Sorghum grains also contain lignocellulosic materials in the hulls, which can be converted to additional ethanol. An integrated process was developed, consisting of the following steps: 1. Extraction of wax with boiling ethanol, which is the final product of the proposed process; 2. Pretreatment of the dewaxed grains with dilute sulfuric acid; 3. Mashing and fermenting of the pretreated grains to produce ethanol. During the fermentation, commercial cellulase was also added to release fermentable sugars from the hulls, which then were converted to additional ethanol. The advantages of the developed process were illustrated with the following results: (1) Wax extracted (determined by weight loss): ~0.3 wt % of total mass. (2) Final ethanol concentration at 25 wt % solid using raw grains: 86.1 g/L. (3) Final ethanol concentration at 25 wt % solid using dewaxed grains: 106.2 g/L (23.3% improvement). (4) Final ethanol concentration at 25 wt % solid using dewaxed and acid-treated grains (1 wt % H2SO4) plus cellulase (CTec2): 117.8 g/L (36.8% improvement).

Detailed and updated distribution records are provided for Buchonomyia thienemanni Fittkau throughout its known western Palaearctic range including Europe, North Africa and the Near East. Two subfossil pupal records from former (dried-up) river channels are included. The species is recorded from Russia for the first time. A review of the known ecology is provided. The species is believed to be ectoparasitic on a species of Trichoptera and a likely host is suggested.

peer-reviewed The insects are the most diverse organisms on this planet and play an essential role in ecosystem functioning, yet we know very little about them. In light of the Convention on Biological Diversity, this paper summarises the known insect species numbers for Ireland and questions whether this is a true refl ection of our insect diversity. The total number of known species for Ireland is 11,422. Using species accumulation curves and a comparison with the British fauna, this study shows that the Irish list is incomplete and that the actual species number is much higher. However, even with a reasonable knowledge of the species in Ireland, insects are such speciose, small, and inconspicuous animals that it is diffi cult to assess species loss. It is impossible to know at one point in time the number of insect species in Ireland and, although it is useful to summarise the known number of species, it is essential that biodiversity indicators, such as the Red List Index, are developed.

Ultrasonic surgical aspirators are used for removal of tumors in the brain and approaches in spine, where a transducer and horn with a central hole fragment and suction tissue. Bone fragmenting and aspirating surgical tips (horns) are discussed for accessing deeper regions in the brain and for emerging spine applications. Attaining resonant frequency, predicting displacements, and monitoring stress distribution and errant motion are afforded with FEM (Finite Element Method) for emerging complex-contoured horns, complementing one-dimensional physical-mathematical models. A full model method with no artificial constraints and a damped forcing function yields agreement between measured horn displacement and FEM results within 2.5% error (e.g. 5 μm in 224 μm p-p) for the new geometry and baseline horns of this study, and 6.8% error (8 μm in 117 μm p-p) for more complex models.

This report documents the results of an effort to investigate a Multilevel Secure (MLS) Database Management System (DBMS) architecture derived by applying the concepts of Trusted Computing Base (TCB) subsetting as described in the Trusted Database Interpretation of the Trusted Computer System Evaluation Criteria (TCSEC) to a trusted subject MLS DBMS architecture. A TCB subset architecture is a trusted systems architecture in which the overall system security policy is hierarchically partitioned and allocated to different parts (subsets) of the system. Each of these parts implements a reference monitor enforcing the corresponding policy. Each part is similar to a conventional reference monitor, with the exception that it may use the resources of the more primitive subsets (lower in the hierarchy) to enforce its security policy (the most primitive subsets use only the hardware). A subset architecture provides significant benefits in the areas of assurance and evaluability. An alternative to a TCB subset DBMS architecture is a 'trusted subject architecture', wherein the DBMS contains some subjects that are not completely constrained by the underlying security kernel. In this report, the design and implementation of a new MLS DBMS architecture that is a hybrid of these two architectures is presented.

An update of the more significant changes affecting Part 1 of ‘A World Catalogue of Chironomidae (Diptera)’ is provided. These concern new taxon names, new combinations and new synonymies that were proposed, as well as omissions and errors detected, since the publication of the Catalogue at the end of 2009.doi: 10.5324/fn.v31i0.1366.Published online: 17 October 2012.

The objective of this paper is to describe an architecture for a multilevel secure distributed database management system (SD-DBMS). This work was part of a project, funded by Rome Air Development Center (RADC), to design a multilevel secure (MLS) database management system (DBMS) capable of processing information at a minimum of three classification levels and/or categories. The SD-DBMS was designed in accordance with the Trusted Computer System Evaluation Criteria (TCSEC) requirements for a Class B3 trusted computer system [Cen85b].

The syntheses, physicochemical properties, and X-ray crystallographic structure determinations of Co 4 (CO) 8 (μ 2 -CO) 2 (μ 4 -PC 6 H 5 ) 2 , 1 , and Co 4 (CO) 6 (P(C 6 H 5 ) 3 ) 2 (μ 2 -CO) 2 (μ 4 -PC 6 H 5 ) 2 , 2 , are described. 1 consists of four Co(CO) 2 groups arranged at the corners of a bonding cobalt rectangle whose shorter two sides are each spanned by a symmetrical bridging carbonyl ligand. This tetramer is capped above and below by quadruply bridging PC 6 H 5 ligands to give an octahedral-like Co 4 P 2 core such that the Co 4 (CO) 10 P 2 fragment (without phenyl rings) approximately conforms to D 2 h symmetry. A substitution of two P(C 6 H 5 ) 3 ligands in place of two carbonyls in 1 to give 2 gives rise to a cis -configuration (with respect to the tetracobalt plane) ideally possessing C 2 symmetry. In 2 , the observed distortion of the Co 4 P 2 core (involving mainly a preferential elongation of two CoP bonds by 0.10 A and a lengthening of the two unbridged CoCo bonds by 0.08 A and the two more rigid CO-bridged CoCo bonds by 0.03 A) is attributed to increased intramolecular nonbonding interactions, while the resulting 0.11 A asymmetrical coordination of each bridging carbonyl to its two cobalt atoms is ascribed to an electronic effect.

The iron cluster, [(n5-C5H5)Fe(μ3-CO)]4, 1, catalyzes the selective hydrogenation of alkynes to alkenes at 100–130° and 100–1000 psig and the selective reduction of terminal alkynes to olefins in the presence of alkenes or internal alkynes. Internal alkynes are slowly reduced to cis olefins, aryl nitro groups to aniline derivatives, and terminal activated carbon-carbon double bonds (methyl acrylate, acrylonitrile) are hydrogenated. The cluster concentration, monitored by high pressure liquid chromatography, was unchanged after 1148 and 1410 turnovers. Cluster 1 was isolated in 95–97% yields after catalytic reduction (1000 turnovers) and no other iron-containing species were detected. After 280 turnovers, the catalyst solution was filtered through an ultrafiltration membrane into a second vessel where hydrogenation of 1-pentyne continued. Fragmentation of 1 tc

The purpose of this pape r is to check the s t a r t l i ng ly high correlation (0.855) which C. Chyat te (1954) has found between critical flicker f requency and a lpha index. Chya t te ' s work was carr ied out in our labora tory three years ago with the same equipment as used in this s tudy and in a previous one by F. P. Fr iedl (1954). I t was on the basis of this lat ter s tudy tha t we became uneasy about Chya t te ' s correlation, which is cer ta inly the highest yet repor ted between measures of cortical a lpha and any other variable. T h e same correlation a t ta ined the very inconspicuous value of 0.]4 in Fr ied l ' s subsequent investigation. Both Chyat te and Fr iedl used a Strobotac Model 631 B with a cardboard shield reducing the i l luminated area to a circular field of 2.5 era. in diameter. By means of a t ranslucent piece of bond pape r the i l lumination of this area was kept un i form at about 0.5 foot candles at the source. The same procedure was followed in the present investigation. In all three studies C F F was measured under conditions of light adapta t ion (LA) . Fo r our subjects, however, C F F measures a f te r 15 nfin. of dark adapta t ion (DA) are also available. The measure of cortical potentials was obtained on the Grass electroencephalograph (Model I I I B) f rom two 1 S, min. records, with a 15 see. interval between recordings dur ing which the subjects were asked to open their eyes and again make themselves comfortable. The actual records were obtained, of course, while the subjects kept their eyes closed and t r ied to relax as much as possible. Monopolar recordings (occipital to ear lobe) were used. The a lpha index is the per eent t ime dur ing which the regular alpha pa t t e rn persists in a given record. The subjects of this s tudy were 56 normal, male college students whose ages ranged f rom 19 to 22 years. They were drawn f rom a larger populat ion in such a manner as to over-represent the two extremes on the Tay lor ' s (1953) Scale of Manifest Anxiety. I t was hypothesized tha t the divergence between the correlations obtained by Chyatte, on the one hand, and by Friedl, on the other, could be due to the anxiety variable which was not included in the former study. Table I gives the comparable results of the three studies. A significant difference (at the .05 level) was found between the mean C F F values of this s tudy and those of Chya t te ' s (t ---2.19). The difference in the mean alpha indices repor ted by Chyat te and by Fr iedl is also significant at the .05 level (t ~2.34). We do not feel, however, that these minor discrepancies can account for the very impressive difference betwee~ the respective correlations. Our own result agrees with that of Fr iedl almost completely and stands in marked contrast to Chyat te 's . Snedecor 's (1946) Chi square test for correlation coefficients yields a value of 42.27 for 2 df which is significant beyond the .00l level. Our hypothesis tha t the difference between Chya t te ' s very high correlation and Fr ied l ' s very low correlation might be due to differences in anxiety-proneness between the two samples was not substantiated. For 24 cases with low Taylor-scores (0-8). the correlation between C F F and a lpha itidex was 0.07; for 26 cases with high Taylor-scores (13-39) it amounted to -0 .02 . These two values are neither significantly di f ferent f~om each other nor f rom zero. Therefore, we f ind ourselves unable to account for the huge difference between Chya t te ' s result and that obtained in the two subsequent studi,,s. I t is t rue that Chya t te ' s subjects were, on the average, older (mean ---26.6 yoars) than ours (mean ~ 20.8 years ; t ~ 6.82) but they were not s ignif icantly older than Fr ied l ' s subjects (mean ~ 25.2 years ; t ~ 1.40).

The centroid factor matrix reported by Trouton and Maxwell in a study of 45 variables taken from an Item Sheet used at the Bethlem Royal and Maudsley Hospitals was subjected to a re-analysis. The six factors were re-rotated obliquely with the object of attaining simple structure. The first two rotated factors were interpreted as a broad schizophrenic reaction and a psychoneurotic factor with emphasis on long duration, gradual onset, and family abnormality. It was hypothesized that both are second order factors appearing at the first order level. The remaining factors were interpreted as an acute situational depression, a retarded depression, a hypochondriacal reaction, and a doubtful belligerence factor. It is concluded that “psychoticism” and “neuroticism” factors have not been established.

(1956). Anderson's Overlap-Hypothesis and the Discontinuities of Growth. The Journal of Genetic Psychology: Vol. 88, No. 1, pp. 95-106.

(1958). Critical Flicker Frequency in Light- and Dark-Adaptation. The Journal of General Psychology: Vol. 58, No. 1, pp. 11-16.

Representative samples of religious educators and parents of adolescents in six denominations (N= 1853) completed questionnaires including 62 goal statements describing what the religiously well-educated and well-socialized youth should be like near the end of high school. All respondents rated the 62 goals as to priority, and by factor-analysis we constructed 10 goal scales. In the Southern Baptist Convention and Church of God, conversion and personal religious life are the foremost goals, while in the Methodist Church, Presbyterian Church in the U.S., Episcopal Church, and Catholic Church, moral maturity is the foremost goal. In these last four denominations the highest-priority goals are rather general to human development, not specific to faith or church commitment. Parent-educator differences are small. The main predictors of the desired goals are denomination and several theological measures-creedal assent, relativism, and moral concreteness.