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PubMed1986

[Demographic transformation in the Austro-Hungarian Monarchy: early fertility decline and the theory of the "demographic transition"].

"The author attempts to expose and explain important elements of the demographic transition in the Austro-Hungarian Monarchy in the last third of the nineteenth century. This is done on the basis of regional differences and time differences of the Coale-Indices (Index of marital fertility, Index of proportion married and Index of overall fertility)." The author considers the differences between marital fertility in rural Hungary and in industrial Austria at the beginning of the demographic transition (SUMMARY IN ENG)

Austria↗

PubMed2006

Measurement of the electronic transition dipole moment by Autler-Townes splitting: Comparison of three- and four-level excitation schemes for the Na2 A 1Sigma(u)+ - X 1Sigma(g)+ system.

We present a fundamentally new approach for measuring the transition dipole moment of molecular transitions, which combines the benefits of quantum interference effects, such as the Autler-Townes splitting, with the familiar R-centroid approximation. This method is superior to other experimental methods for determining the absolute value of the R-dependent electronic transition dipole moment function mu(e)(R), since it requires only an accurate measurement of the coupling laser electric field amplitude and the determination of the Rabi frequency from an Autler-Townes split fluorescence spectral line. We illustrate this method by measuring the transition dipole moment matrix element for the Na2 A 1Sigma(u)+ (v' = 25, J' = 20e)-X 1Sigma(g)+ (v" = 38, J" = 21e) rovibronic transition and compare our experimental results with our ab initio calculations. We have compared the three-level (cascade) and four-level (extended Lambda) excitation schemes and found that the latter is preferable in this case for two reasons. First, this excitation scheme takes advantage of the fact that the coupling field lower level is outside the thermal population range. As a result vibrational levels with larger wave function amplitudes at the outer turning point of vibration lead to larger transition dipole moment matrix elements and Rabi frequencies than those accessible from the equilibrium internuclear distance of the thermal population distribution. Second, the coupling laser can be "tuned" to different rovibronic transitions in order to determine the internuclear distance dependence of the electronic transition dipole moment function in the region of the R-centroid of each coupling laser transition. Thus the internuclear distance dependence of the transition moment function mu(e)(R) can be determined at several very different values of the R centroid. The measured transition dipole moment matrix element for the Na2 A 1Sigma(u)+ (v' = 25, J' = 20e)-X 1Sigma(g)+ (v" = 38, J" = 21e) transition is 5.5+/-0.2 D compared to our ab initio value of 5.9 D. By using the R-centroid approximation for this transition the corresponding experimental electronic transition dipole moment is 9.72 D at Rc = 4.81 A, in good agreement with our ab initio value of 10.55 D.

Journal Article↗

PubMed1994

B-Z transition of synthetic oligonucleotides containing non-Z forming elements.

Ten oligonucleotides of the length 8-12 base pairs have been synthesized, which contain, in addition to the obligatory sequences CG/CG, sequences not favorable for the transition to the Z conformation (A.T pairs, GG/CC or AA/TT sequences). Conformational transitions of these oligonucleotides in high concentrations of NaClO4 in the absence and in the presence of Ni2+ were investigated using CD spectroscopy. The B-Z transition is affected by the length and sequence of the oligonucleotide. Increasing the NaClO4 concentration alone the transition of only one of the oligonucleotides studied. (CGCGCGTGCACGCGCG)2, can be induced. Other oligonucleotides remain in the B conformation or only partial transition to the Z conformation can be observed. Most other oligonucleotides can be converted into the Z conformation at intermediate concentrations of NaClO4 (2.0-3.2 M) by an addition of Ni2+ ions. In some cases, however, Ni2+ can destabilize the double stranded structure of the sample. We have studied the effect of the presence of A.T pairs in the G.C containing oligonucleotides and the effect of the presence of pu-pu/pyr-pyr sequences. The presence of the latter sequences in the Z form implicates the formation of a Z-Z'junction which makes the transition quite difficult. Despite the fact that some oligonucleotides contained several structural elements not favorable for the transition, we did not find any sequence which would completely block the ability of the oligonucleotide to adopt the Z conformation.

Base Composition↗

PubMed1991

Factors influencing perceived angular velocity.

The assumption that humans are able to perceive and process angular kinematics is critical to many structure-from-motion and optical flow models. The current studies investigate this sensitivity, and examine several factors likely to influence angular velocity perception. In particular, three factors are considered: (1) the extent to which perceived angular velocity is determined by edge transitions of surface elements, (2) the extent to which angular velocity estimates are influenced by instantaneous linear velocities of surface elements, and (3) whether element-velocity effects are related to three-dimensional (3-D) tangential velocities or to two-dimensional (2-D) image velocities. Edge-transition rate biased angular velocity estimates only when edges were highly salient. Element velocities influenced perceived angular velocity; this bias was related to 2-D image velocity rather than 3-D tangential velocity. Despite these biases, however, judgments were most strongly determined by the true angular velocity. Sensitivity to this higher order motion parameter was surprisingly good, for rotations both in depth (y-axis) and parallel to the line of sight (z-axis).

Acceleration↗

PubMed2002

The unique aspects of the nutrition transition in South Korea: the retention of healthful elements in their traditional diet.

OBJECTIVE: The purposes of this paper are to describe the unique aspects of the nutrition transition in South Korea, including trends in food consumption and obesity, patterns of morbidity and mortality; to focus on efforts to maintain the traditional diet in the midst of rapid economic growth and the introduction of Western culture; and to provide insights for other countries. DESIGN: We analysed secondary dietary intake, anthropometric, morbidity and mortality data from published reports and articles. RESULTS: In South Korea, the level and rate of increase in fat intake have remained very low, whereas vegetable intake has been high and fruit intake has increased greatly. South Korea also has a relatively low prevalence of obesity compared with other Asian countries. The traditional Korean diet is a low-fat and high-vegetable diet. Therefore, the government and nutrition specialists have been initiating numerous efforts to advertise and teach the public that the traditional diet is a healthy diet. They are also working on revival of the traditional diet using an approach that is acceptable to contemporary Koreans. CONCLUSIONS: The nutrition transition in South Korea is unique. A range of government, nutrition specialists and some private organisation efforts has worked to retain healthful elements of the traditional diet in South Korea. The continued low level of total fat in the overall diet and the high intake of fruits and vegetables bode well for South Korea.

Adult↗

PubMed1995

Nuclear factor binding to a DNA sequence element that represses MMTV transcription induces a structural transition and leads to the contact of single-stranded binding proteins with DNA.

NRE1 is a DNA sequence element in the long terminal repeat of mouse mammary tumor virus through which viral transcription is repressed. In addition to double-stranded DNA binding, both upper- and lower-stranded NRE1 binding activities occur in nuclear extracts. All three binding activities appear to be important for transcriptional effects. We report that occupancy of NRE1 within linear double-stranded NRE1 induces a structural transition in upstream flanking DNA that is facilitated by Mg2+. This transition was reflected by the striking DNase I sensitivity of the DNA. As Mg2+ concentration was increased, discrete DNase I hypersensitivity on one face of the DNA progressed to complete degradation of template. On the DNA face opposite the DNase I hypersensitivity, Mg2+ promoted regularly spaced cleavage by the single-strand-specific cleavage agents KMnO4 and S1 nuclease. Induction of degradation by DNase I occurred independently of MMTV sequences flanking NRE1, because nuclear extract-dependent DNase I sensitivity was conferred to an unrelated DNA fragment by introduction of a 23-bp NRE1-containing oligonucleotide. UV protein-DNA cross-linking revealed that addition of Mg2+ to a double-stranded NRE1 DNA binding assay induced conversion from a double- to a single-stranded protein-DNA cross-linking pattern. Thus, nuclear factor binding to NRE1 induces changes in DNA topology that promote the direct contact of single-stranded NRE1 binding factors with DNA.

Animals↗

PubMed1995

Exploring the energy surface of protein folding by structure-reactivity relationships and engineered proteins: observation of Hammond behavior for the gross structure of the transition state and anti-Hammond behavior for structural elements for unfolding/folding of barnase.

The structure of alpha-helix 1 (residues 6-18) in the transition state for the unfolding of barnase has been previously characterized by comparing the kinetics and thermodynamics of folding of wild-type protein with those of mutants whose side chains have been cut back, in the main, to that of alanine. The structure of the transition state has now been explored further by comparing the kinetics and thermodynamics of folding of glycine mutants with those of the alanine mutants at solvent-exposed positions in the alpha-helices of barnase. Such "Ala-->Gly scanning" provides a general procedure for examining the structure of solvent-exposed regions in the transition state. A gradual change of structure of the transition state was detected as helix 1 becomes increasingly destabilized on mutation. The extent of change of structure of helix 1 in the transition state for the mutant proteins was probed by a further round of Ala-->Gly scanning of those mutants. Destabilization of the helix 1 was found to cause the overall transition state for unfolding to become closer in structure to that of the folded protein. This is analogous to the conventional Hammond effect in physical-organic chemistry whereby the transition state moves parallel to the reaction coordinate with change in structure. But, paradoxically, the structure of helix 1 itself becomes less folded in the transition state as helix 1 becomes destabilized. This is analogous, however, to the rarer anti-Hammond effect in which there is movement perpendicular to the reaction coordinate. These observations are rationalized by plotting correlation diagrams of degree of formation of individual elements of structure against the degree of formation of overall structure in the transition state. There is a relatively smooth movement of the degree of compactness in the transition state against changes in activation energy on mutation that suggests a smooth movement of the transition state along the energy surface on mutation rather than a switch between two different parallel pathways. The results are consistent with the transition state having closely spaced energy levels. Helix 1, which appears to be an initiation point and forms early in the folding of wild-type protein, may be radically destabilized to the extent that it forms late in the folding of mutants. The order of events in folding may thus not be crucial.

Alanine↗

PubMed2000

Polyanionic Clusters and Networks of the Early p-Element Metals in the Solid State: Beyond the Zintl Boundary.

Reduction of p-element (post-transition) metals and metalloids by alkali metals leads to many salts containing polyatomic clusters or network anions of these elements. The earliest solvated examples were referred to as Zintl ions. Synthetic explorations have now established that many of the clusters can in fact be obtained from neat (solvent free) high-temperature reactions of binary to quaternary systems, particularly for the heavier tetrel (group 14) and triel (group 13) elements. Some synthetic tricks have also proven useful. Electronic guidelines such as Wade's rules, known to account well for other types of electron-deficient cluster bonding, are widely applicable to these compounds, but numerous hypoelectronic (electron-poor) trielide salts have also been discovered. These developments also extend to related infinite network structures and Zintl (valence) compounds. The Zintl boundary designation traditionally delineated the tetrel elements that form salts with the active metals from those of the triel and earlier elements that were once thought to generate only intermetallic phases. The distinction no longer seems appropriate, at least with regard to some alkali-metal compounds of the triel elements.

Journal Article↗

PubMed1999

Sequential analysis of juvenile isolation-induced decreased social behavior in the adult rat.

The consequences of juvenile isolation on adult social behavior were studied in detail using two different analysis methods: frequency, duration, and latency of behavioral elements, and sequential analysis. Rats were either isolated or socially housed during weeks 4 and 5 of age, and after the isolation period housed in pairs with a rat of identical housing condition until the time of testing at 12 weeks of age. Juvenile isolation caused marked effects on the frequency, duration, and latency of various social behavioral elements, whereas the non-social activities such as ambulation, rearing, and self-grooming were hardly affected. Juvenile isolation reduced social exploration, anogenital sniffing, and approach/following and increased the latency to the first occurrence of these social behavioral elements. In contrast, the sequential analysis revealed that the structure of social behavior was barely affected by juvenile isolation. Some transitions were less pronounced in juvenile isolated rats compared to non-isolated rats, but no significant differences were observed in transitions between social elements. Thus, juvenile isolation bisected the time spent on adult social interactions, whereas it did not disrupt the sequential structure of social behavior. The present data suggest that juvenile isolation reduced the motivation for adult social behavior, but when social contact is initiated, a relatively normal social behavioral pattern is displayed.

Aging↗

PubMed2001

Release of trace elements in wetlands: role of seasonal variability.

Dissolved concentrations were determined for Fe, Mn, Al, Cu, Zn, La, U, Th, Cd and As in a wetland and its recipient stream to reveal the effect of seasonal changes in environmental conditions on the cycling and transfer of trace elements at the transition between terrestrial and aquatic ecosystems. These preliminary results from the wetland show marked seasonal changes in dissolved concentration for all elements except Zn and Cu. Concentrations are found to be low until about mid-February and then increase abruptly. The onset of trace element release appears to coincide with a marked decline in redox potential and increase of organic carbon content. Because this decline is itself correlated with a pronounced increase in temperature and dissolved Fe. Mn and organic carbon content, we suggest that the microorganisms which use soil iron and manganese oxy-hydroxides as electron acceptors catalyzed the change in redox conditions and induced an increase of DOC. Temporal changes were also observed in the recipient stream which showed marked positive concentration peaks during stormflow events (except Zn). The seasonal processes occurring in the wetland appear to play a major role in determining the amount of trace elements which are transferred from the wetland to the river.

Copper↗

PubMed2001

Two-photon absorption and nonlinear optical properties of octupolar molecules.

Two-photon absorption (TPA) cross sections of four representative series of octupolar molecules are theoretically investigated. The general structure--TPA-property relationship is described by using the effective four-state valence-bond three-charge-transfer model. As the charge-transfer character of the ground electronic state increases due to the strong donors or acceptors, (i) the transition dipole matrix elements between the ground and 2-fold degenerate excited states increase, (ii) the energy gap decreases, and consequently (iii) the TPA transition amplitude monotonically increases. Thus, the design strategy to maximize the TPA cross section of the octupolar molecule is established. On the basis of the four-state model, the first hyperpolarizability of the octupolar molecule is found to be linearly proportional to the TPA cross section. This theoretical relationship is confirmed by using the ab initio calculation results. The Hammett correlation analysis of the TPA cross section and first hyperpolarizability is also presented.

Journal Article↗

PubMed1998

Concerted formation of macromolecular Suppressor-mutator transposition complexes.

Transposition of the maize Suppressor-mutator (Spm) transposon requires two element-encoded proteins, TnpA and TnpD. Although there are multiple TnpA binding sites near each element end, binding of TnpA to DNA is not cooperative, and the binding affinity is not markedly affected by the number of binding sites per DNA fragment. However, intermolecular complexes form cooperatively between DNA fragments with three or more TnpA binding sites. TnpD, itself not a sequence-specific DNA-binding protein, binds to TnpA and stabilizes the TnpA-DNA complex. The high redundancy of TnpA binding sites at both element ends and the protein-protein interactions between DNA-bound TnpA complexes and between these and TnpD imply a concerted transition of the element from a linear to a protein crosslinked transposition complex within a very narrow protein concentration range.

Base Sequence↗

PubMed1982

Golgi complex beads in vertebrates and their relationship with clathrin coats.

Addition of tannic acid to the primary glutaraldehyde fixative and the viewing of thin sections by stereo electron microscopy greatly simplifies the detection of vertebrate cell Golgi complex beads which are otherwise difficult to see since they do not stain with bismuth. These results confirm the generality of conclusions from experiments on arthropod beads which are easily observed because of their bismuth affinity. In vertebrate and arthropod cells, bead rings encircle the base of forming transition vesicles below the growing portion of the vesicle that is covered with a clathrin coat. Their unique position at such a sharp functional and structural boundary in intercompartmental transport suggests that the bead rings may specify a select region of rough endoplasmic reticulum devoid of ribosomes where clathrin coats can induce transition vesicle formation and prevent intermixing of the elements of a returning transition vesicle.

Animals↗

PubMed2003

Chaotic cluster itinerancy and hierarchical cluster trees in electrochemical experiments.

Experiments on an array of 64 globally coupled chaotic electrochemical oscillators were carried out. The array is heterogeneous due to small variations in the properties of the electrodes and there is also a small amount of noise. Over some ranges of the coupling parameter, dynamical clustering was observed. The precision-dependent cluster configuration is analyzed using hierarchical cluster trees. The cluster configurations varied with time: spontaneous changes of number of clusters and their configurations were detected. Simple transitions occurred with the switch of a single element or groups of elements. During more complicated transitions subclusters were exchanged among clusters but original cluster configurations were revisited. At weaker coupling the system itinerated among lower-dimensional quasistationary chaotic two-cluster states and higher-dimensional states with many clusters. In this region the transitions showed characteristics of on-off intermittency.

Cluster Analysis↗

PubMed2006

Growing up ready: a shared management approach.

In order to help youth with physical disabilities and their families to plan for the transition to adulthood, well-planned service delivery is essential. This paper provides an account of the work of a children's rehabilitation centre to develop a transition framework reflecting evidence-based practice. Examination of current transition practices, a review of the literature, and site visits to health care facilities and universities were conducted to identify promising practices in the field of transition to adult services. A transition framework was designed to facilitate the adoption of a shared management approach for helping families and their children to grow up ready. Key elements of the transition framework are described and future plans discussed.

Child↗

PubMed2006

High-pressure structures and phase transformations in elemental metals.

At ambient conditions the great majority of the metallic elements have simple crystal structures, such as face-centred or body-centred cubic, or hexagonal close-packed. However, when subjected to very high pressures, many of the same elements undergo phase transitions to low-symmetry and surprisingly complex structures, an increasing number of which are being found to be incommensurate. The present critical review describes the high-pressure behaviour of each of the group 1 to 16 metallic elements in detail, summarising previous work and giving the best present understanding of the structures and transitions at ambient temperature. The principal results and emerging systematics are then summarised and discussed.

Journal Article↗

PubMed2005

Systematically convergent basis sets for transition metals. I. All-electron correlation consistent basis sets for the 3d elements Sc-Zn.

Sequences of basis sets that systematically converge towards the complete basis set (CBS) limit have been developed for the first-row transition metal elements Sc-Zn. Two families of basis sets, nonrelativistic and Douglas-Kroll-Hess (-DK) relativistic, are presented that range in quality from triple-zeta to quintuple-zeta. Separate sets are developed for the description of valence (3d4s) electron correlation (cc-pVnZ and cc-pVnZ-DK; n = T,Q, 5) and valence plus outer-core (3s3p3d4s) correlation (cc-pwCVnZ and cc-pwCVnZ-DK; n = T,Q, 5), as well as these sets augmented by additional diffuse functions for the description of negative ions and weak interactions (aug-cc-pVnZ and aug-cc-pVnZ-DK). Extensive benchmark calculations at the coupled cluster level of theory are presented for atomic excitation energies, ionization potentials, and electron affinities, as well as molecular calculations on selected hydrides (TiH, MnH, CuH) and other diatomics (TiF, Cu2). In addition to observing systematic convergence towards the CBS limits, both 3s3p electron correlation and scalar relativity are calculated to strongly impact many of the atomic and molecular properties investigated for these first-row transition metal species.

Journal Article↗

PubMed2000

[Sarcomatoid carcinoma of the urinary bladder: report of a case].

The patient was a 78-year-old man with gross hematuria. A non-papillary and non-pedunculated tumor was found on the posterior wall of the bladder by cystoscopic examination. Total cystectomy with construction of ileal conduit was performed. Histologically, the tumor was composed of carcinomatous and sarcomatous elements. The carcinomatous element was compatible with grade 3 transitional cell carcinoma. The sarcomatous element was composed of osteosarcomatous, chondrosarcomatous pattern and undifferentiated malignant spindle cell component. Immunohistochemical examination demonstrated the presence of keratin, cytokeratin and epithelial membrane antigen in both carcinomatous and sarcomatous elements. Therefore, we diagnosed this tumor as sarcomatoid carcinoma. The patient has remained well without any evidence of recurrence for 10 months after operation.

Aged↗