Reappraisal of the Utility of the Tilt-table in the Investigation of Venous Disease†

OBJECTIVES

Without gravity opposing drainage, most venous diseases would not exist. Therefore, manoeuvres that assess venous function should include gravity. The aim was to "dose" gravity in subjects using static positions and dynamic angulations on a tilt-table and to assess its effects with air plethysmography (APG) and duplex ultrasound over the femoral vein.

METHODS

Three groups (providing n = 11 legs each) were compared. (a) A control group, without clinical or duplex evidence of venous disease. (b) An obstruction group, with past iliofemoral deep vein thrombosis. (3) A reflux group, with primary varicose veins. A manually operated tilt-table ranging from -70° to 40° in the Trendelenburg position provided rapid tilting (<3 s). The changes in calf volume at -70° (almost standing), -45° (reclining), and 40° (legs-up) were recorded with APG, as well as the rate and duration of the changes. The minor diameter of the femoral vein was recorded at the three tilt positions.

RESULTS

The results were expressed as median (interquartile range). The total working venous volume (mL) in the reflux group was significantly increased: 202 (180-240) mL versus the controls at 138 (119-198) mL, p = .008, and versus the legs with obstruction at 117 (80-154) mL, p < .0005. The venous drainage index (VDI) in mL/second in the obstructed group was significantly reduced: 7 (6-9.6) mL/second, versus the controls at 17.4 (13.9-27.2) mL/second, p < .0005, and versus the legs with varicose veins at 28.1 (25.4-34.4) mL/second, p < .0005. The venous filling index (VFI) in mL/second in the reflux group was significantly increased: 8.1 (4.2-10) mL/second versus the controls at 1.8 (1-2.1) mL/second, p < .0005. The VDI cut-off point discriminating obstruction was ≤10.8 mL/second and the VFI discriminating reflux was ≥ 2.9 mL/second. The femoral vein diameter was reduced significantly with increasing leg elevation.

CONCLUSIONS

Manoeuvres using APG on a tilt-table have the potential to quantify the contributions of global obstruction and reflux (mL/second) in patients with venous disease.

^{7}Be(n,α)^{4}He Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN

The energy-dependent cross section of the ^{7}Be(n,α)^{4}He reaction, of interest for the so-called cosmological lithium problem in big bang nucleosynthesis, has been measured for the first time from 10 meV to 10 keV neutron energy. The challenges posed by the short half-life of ^{7}Be and by the low reaction cross section have been overcome at n_TOF thanks to an unprecedented combination of the extremely high luminosity and good resolution of the neutron beam in the new experimental area (EAR2) of the n_TOF facility at CERN, the availability of a sufficient amount of chemically pure ^{7}Be, and a specifically designed experimental setup. Coincidences between the two alpha particles have been recorded in two Si-^{7}Be-Si arrays placed directly in the neutron beam. The present results are consistent, at thermal neutron energy, with the only previous measurement performed in the 1960s at a nuclear reactor. The energy dependence reported here clearly indicates the inadequacy of the cross section estimates currently used in BBN calculations. Although new measurements at higher neutron energy may still be needed, the n_TOF results hint at a minor role of this reaction in BBN, leaving the long-standing cosmological lithium problem unsolved.

Total Absorption Spectroscopy Study of (92)Rb Decay: A Major Contributor to Reactor Antineutrino Spectrum Shape

The antineutrino spectra measured in recent experiments at reactors are inconsistent with calculations based on the conversion of integral beta spectra recorded at the ILL reactor. (92)Rb makes the dominant contribution to the reactor antineutrino spectrum in the 5-8 MeV range but its decay properties are in question. We have studied (92)Rb decay with total absorption spectroscopy. Previously unobserved beta feeding was seen in the 4.5-5.5 region and the GS to GS feeding was found to be 87.5(25)%. The impact on the reactor antineutrino spectra calculated with the summation method is shown and discussed.

Enhanced γ-Ray Emission from Neutron Unbound States Populated in β Decay

Total absorption spectroscopy is used to investigate the β-decay intensity to states above the neutron separation energy followed by γ-ray emission in (87,88)Br and (94)Rb. Accurate results are obtained thanks to a careful control of systematic errors. An unexpectedly large γ intensity is observed in all three cases extending well beyond the excitation energy region where neutron penetration is hindered by low neutron energy. The γ branching as a function of excitation energy is compared to Hauser-Feshbach model calculations. For (87)Br and (88)Br the γ branching reaches 57% and 20%, respectively, and could be explained as a nuclear structure effect. Some of the states populated in the daughter can only decay through the emission of a large orbital angular momentum neutron with a strongly reduced barrier penetrability. In the case of neutron-rich (94)Rb the observed 4.5% branching is much larger than the calculations performed with standard nuclear statistical model parameters, even after proper correction for fluctuation effects on individual transition widths. The difference can be reconciled by introducing an enhancement of 1 order of magnitude in the photon strength to neutron strength ratio. An increase in the photon strength function of such magnitude for very neutron-rich nuclei, if it proves to be correct, leads to a similar increase in the (n,γ) cross section that would have an impact on r process abundance calculations.

Word structures of Granada Spanish-speaking preschoolers with typical versus protracted phonological development

BACKGROUND

Research on children's word structure development is limited. Yet, phonological intervention aims to accelerate the acquisition of both speech-sounds and word structure, such as word length, stress or shapes in CV sequences. Until normative studies and meta-analyses provide in-depth information on this topic, smaller investigations can provide initial benchmarks for clinical purposes.

AIMS

To provide preliminary reference data for word structure development in a variety of Spanish with highly restricted coda use: Granada Spanish (similar to many Hispano-American varieties). To be clinically applicable, such data would need to show differences by age, developmental typicality and word structure complexity. Thus, older typically developing (TD) children were expected to show higher accuracy than younger children and those with protracted phonological development (PPD). Complex or phonologically marked forms (e.g. multisyllabic words, clusters) were expected to be late developing.

METHODS & PROCEDURES

Participants were 59 children aged 3-5 years in Granada, Spain: 30 TD children, and 29 with PPD and no additional language impairments. Single words were digitally recorded by a native Spanish speaker using a 103-word list and transcribed by native Spanish speakers, with confirmation by a second transcriber team and acoustic analysis. The program Phon 1.5 provided quantitative data.

OUTCOMES & RESULTS

In accordance with expectations, the TD and older age groups had better-established word structures than the younger children and those with PPD. Complexity was also relevant: more structural mismatches occurred in multisyllabic words, initial unstressed syllables and clusters. Heterosyllabic consonant sequences were more accurate than syllable-initial sequences. The most common structural mismatch pattern overall was consonant deletion, with syllable deletion most common in 3-year-olds and children with PPD.

CONCLUSIONS & IMPLICATIONS

The current study provides preliminary reference data for word structure development in a Spanish variety with restricted coda use, both by age and types of word structures. Between ages 3 and 5 years, global measures (whole word match, word shape match) distinguished children with typical versus protracted phonological development. By age 4, children with typical development showed near-mastery of word structures, whereas 4- and 5-year-olds with PPD continued to show syllable deletion and cluster reduction, especially in multisyllabic words. The results underline the relevance of multisyllabic words and words with clusters in Spanish phonological assessment and the utility of word structure data for identification of protracted phonological development.

Neutron capture cross section of unstable 63Ni: implications for stellar nucleosynthesis

The 63Ni(n,γ) cross section has been measured for the first time at the neutron time-of-flight facility n_TOF at CERN from thermal neutron energies up to 200 keV. In total, capture kernels of 12 (new) resonances were determined. Maxwellian averaged cross sections were calculated for thermal energies from   kT=5-100  keV with uncertainties around 20%. Stellar model calculations for a 25M⊙ star show that the new data have a significant effect on the s-process production of 63Cu, 64Ni, and 64Zn in massive stars, allowing stronger constraints on the Cu yields from explosive nucleosynthesis in the subsequent supernova.