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1.
Phys Rev Lett ; 132(12): 122701, 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38579210

ABSTRACT

^{140}Ce(n,γ) is a key reaction for slow neutron-capture (s-process) nucleosynthesis due to being a bottleneck in the reaction flow. For this reason, it was measured with high accuracy (uncertainty ≈5%) at the n_TOF facility, with an unprecedented combination of a high purity sample and low neutron-sensitivity detectors. The measured Maxwellian averaged cross section is up to 40% higher than previously accepted values. Stellar model calculations indicate a reduction around 20% of the s-process contribution to the Galactic cerium abundance and smaller sizeable differences for most of the heavier elements. No variations are found in the nucleosynthesis from massive stars.

2.
J Dairy Sci ; 106(5): 3706-3718, 2023 May.
Article in English | MEDLINE | ID: mdl-36907757

ABSTRACT

Previous studies ex vivo suggested that plant bioactive lipid compounds (PBLC) can increase ruminal calcium absorption. Therefore, we hypothesized that PBLC feeding around calving may potentially counteract hypocalcemia and support performance in postpartum dairy cows. The corresponding aim of the study was to investigate the effect of PBLC feeding on blood minerals in Brown Swiss (BS) and hypocalcemia-susceptible Holstein Friesian (HF) cows during the period from d -2 to 28 relative to calving and on milk performance until d 80 of lactation. A total of 29 BS cows and 41 HF cows were divided each into a control (CON) and PBLC treatment group. The latter was supplemented with 1.7 g/d menthol-rich PBLC from 8 d before expected calving to 80 d postpartum. Milk yield and composition, body condition score and blood minerals were measured. Feeding PBLC induced a significant breed × treatment interaction for iCa, supporting that PBLC increased iCa exclusively in HF cows; the increase was 0.03 mM over the whole period and 0.05 mM from d 1 to 3 after calving. Subclinical hypocalcemia was seen in one BS-CON and 8 HF-CON cows and 2 BS-PBLC and 4 HF-PBLC cows. Clinical milk fever was detected only in HF cows (2 HF-CON and one HF-PBLC). Other tested blood minerals, such as sodium, chloride, and potassium, as well as blood glucose, were neither affected by PBLC feeding nor breed, nor were their 2-way interactions, except for higher sodium levels in PBLC cows on d 21. Body condition score showed no effect of treatment, except for a lower body condition score in BS-PBLC compared with BS-CON at d 14. Dietary PBLC increased milk yield, milk fat yield, and milk protein yield at 2 consecutive dairy herd improvement test days. As indicated by treatment × day interactions, energy-corrected milk yield and milk lactose yield were increased by PBLC on the first test day only, and milk protein concentration decreased from test d 1 to test d 2 in CON only. The concentrations of fat, lactose, and urea, as well as somatic cell count, were not affected by treatment. The weekly milk yield over the first 11 wk of lactation was 29.5 kg/wk higher for PBLC versus CON across breeds. It is concluded that the applied PBLC induced a small but measurable improvement of calcium status in HF cows in the study period and had additional positive effects on milk performance in both breeds.


Subject(s)
Cattle Diseases , Hypocalcemia , Female , Cattle , Animals , Lactation , Calcium , Hypocalcemia/veterinary , Lactose , Plant Breeding , Postpartum Period , Milk Proteins , Calcium, Dietary , Lipids , Diet/veterinary
3.
Eur Phys J A Hadron Nucl ; 58(12): 239, 2022.
Article in English | MEDLINE | ID: mdl-36514540

ABSTRACT

Neutron capture reaction cross sections on 74 Ge are of importance to determine 74 Ge production during the astrophysical slow neutron capture process. We present new resonance data on 74 Ge( n , γ ) reactions below 70 keV neutron energy. We calculate Maxwellian averaged cross sections, combining our data below 70 keV with evaluated cross sections at higher neutron energies. Our stellar cross sections are in agreement with a previous activation measurement performed at Forschungszentrum Karlsruhe by Marganiec et al., once their data has been re-normalised to account for an update in the reference cross section used in that experiment.

4.
Phys Rev Lett ; 125(14): 142701, 2020 Oct 02.
Article in English | MEDLINE | ID: mdl-33064503

ABSTRACT

The neutron capture cross sections of several unstable nuclides acting as branching points in the s process are crucial for stellar nucleosynthesis studies. The unstable ^{171}Tm (t_{1/2}=1.92 yr) is part of the branching around mass A∼170 but its neutron capture cross section as a function of the neutron energy is not known to date. In this work, following the production for the first time of more than 5 mg of ^{171}Tm at the high-flux reactor Institut Laue-Langevin in France, a sample was produced at the Paul Scherrer Institute in Switzerland. Two complementary experiments were carried out at the neutron time-of-flight facility (n_TOF) at CERN in Switzerland and at the SARAF liquid lithium target facility at Soreq Nuclear Research Center in Israel by time of flight and activation, respectively. The result of the time-of-flight experiment consists of the first ever set of resonance parameters and the corresponding average resonance parameters, allowing us to make an estimation of the Maxwellian-averaged cross sections (MACS) by extrapolation. The activation measurement provides a direct and more precise measurement of the MACS at 30 keV: 384(40) mb, with which the estimation from the n_TOF data agree at the limit of 1 standard deviation. This value is 2.6 times lower than the JEFF-3.3 and ENDF/B-VIII evaluations, 25% lower than that of the Bao et al. compilation, and 1.6 times larger than the value recommended in the KADoNiS (v1) database, based on the only previous experiment. Our result affects the nucleosynthesis at the A∼170 branching, namely, the ^{171}Yb abundance increases in the material lost by asymptotic giant branch stars, providing a better match to the available pre-solar SiC grain measurements compared to the calculations based on the current JEFF-3.3 model-based evaluation.

5.
Phys Rev Lett ; 121(4): 042701, 2018 Jul 27.
Article in English | MEDLINE | ID: mdl-30095928

ABSTRACT

We report on the measurement of the ^{7}Be(n,p)^{7}Li cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n_TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous time-of-flight measurements performed on this reaction did not cover the energy window of interest for BBN, and they showed a large discrepancy between each other. The measurement was performed with a Si telescope and a high-purity sample produced by implantation of a ^{7}Be ion beam at the ISOLDE facility at CERN. While a significantly higher cross section is found at low energy, relative to current evaluations, in the region of BBN interest, the present results are consistent with the values inferred from the time-reversal ^{7}Li(p,n)^{7}Be reaction, thus yielding only a relatively minor improvement on the so-called cosmological lithium problem. The relevance of these results on the near-threshold neutron production in the p+^{7}Li reaction is also discussed.

6.
Bull Entomol Res ; 107(5): 699-704, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28290255

ABSTRACT

Leucopis argenticollis (Zetterstedt) and Leucopis piniperda (Malloch) are known to feed on the lineage of Adelges tsugae Annand that is native to western North America, but it is not known if they will survive on the lineage that was introduced from Japan to the eastern USA. In 2014, western Leucopis spp. larvae were brought to the laboratory and placed on A. tsugae collected in either Washington (North American A. tsugae lineage) or Connecticut (Japanese lineage). There were no significant differences in survival or developmental times between flies reared on the two different adelgid lineages. In 2015 and 2016, western Leucopis spp. adults were released at two different densities onto enclosed branches of A. tsugae infested eastern hemlock (Tsuga canadensis (L.) Carr.) in Tennessee and New York. Cages were recovered and their contents examined 4 weeks after release at each location. Leucopis spp. larvae and puparia of the F1 generation were recovered at both release locations and adults of the F1 generation were collected at the Tennessee location. The number of Leucopis spp. offspring collected increased with increasing adelgid density, but did not differ by the number of adult flies released. Flies recovered from cages and flies collected from the source colony were identified as L.argenticollis and L. piniperda using DNA barcoding. These results demonstrate that Leucopis spp. from the Pacific Northwest are capable of feeding and developing to the adult stage on A. tsugae in the eastern USA and they are able to tolerate environmental conditions during late spring and early summer at the southern and northern extent of the area invaded by A. tsugae in the eastern USA.


Subject(s)
Diptera/growth & development , Hemiptera , Pest Control, Biological , Predatory Behavior , Animals , Female , Food Chain , Male , Tsuga , United States
7.
Phys Rev Lett ; 117(15): 152701, 2016 Oct 07.
Article in English | MEDLINE | ID: mdl-27768364

ABSTRACT

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.

8.
Phys Rev Lett ; 117(1): 012501, 2016 Jul 01.
Article in English | MEDLINE | ID: mdl-27419564

ABSTRACT

The ß-delayed neutron emission probabilities of neutron rich Hg and Tl nuclei have been measured together with ß-decay half-lives for 20 isotopes of Au, Hg, Tl, Pb, and Bi in the mass region N≳126. These are the heaviest species where neutron emission has been observed so far. These measurements provide key information to evaluate the performance of nuclear microscopic and phenomenological models in reproducing the high-energy part of the ß-decay strength distribution. This provides important constraints on global theoretical models currently used in r-process nucleosynthesis.

9.
Neuroscience ; 313: 23-35, 2016 Jan 28.
Article in English | MEDLINE | ID: mdl-26608124

ABSTRACT

The time course of the induction of enzymes responsible for the formation of prostaglandin E2 (PGE2) after an inflammatory insult, in relation to the concomitant febrile response, suggests that peripherally generated PGE2 is involved in the induction of the early phase of fever, while centrally produced PGE2 exerts pyrogenic capacities during the later stages of fever within the hypothalamic median preoptic nucleus (MnPO). The actions of peripherally derived PGE2 on the brain might occur at the level of the organum vasculosum laminae terminalis (OVLT), which lacks a tight blood-brain barrier and is implicated in fever, while the effects of PGE2 within the MnPO might interfere with glutamatergic neurotransmission within a recently characterized central efferent pathway for the activation of cold-defence reactions. Using the fura-2 ratio imaging technique we, therefore, measured changes of the intracellular Ca(2+)-concentration in primary neuroglial microcultures of rat OVLT and MnPO stimulated with PGE2 and/or glutamate. In cultures from the OVLT, as opposed to those derived from the MnPO, substantial numbers of neurons (8% of 385), astrocytes (19% of 645) and microglial cells (28% of 43) directly responded to PGE2 with a transient increase of intracellular Ca(2+). The most pronounced effect of PGE2 on cells from MnPO microcultures was its modulatory influence on the strength of glutamate-induced Ca(2+)-signals. In 72 out of 512 neurons and in 105 out of 715 astrocytes PGE2 significantly augmented glutamate-induced Ca(2+)-signals. About 30% of these neurons were GABAergic. These observations are in agreement with putative roles of peripheral PGE2 as a directly acting circulating agent at the level of the OVLT, and of central MnPO-intrinsic PGE2 as an enhancer of glutamatergic neurotransmission, which causes disinhibition of thermogenic heat production, a crucial component for the manifestation of fever. In microcultures from both brain sites investigated incubation with PGE2 significantly reduced the lipopolysaccharide-induced release of cytokines (tumor necrosis factor-α and interleukin-6) into the supernatant. PGE2, thus, seems to be involved in a negative feed-back loop to limit the strength of the brain inflammatory process and to play a dual role with pro- as well as anti-inflammatory properties.


Subject(s)
Dinoprostone/metabolism , Organum Vasculosum/metabolism , Preoptic Area/metabolism , Animals , Calcium/metabolism , Calcium Signaling/drug effects , Calcium Signaling/physiology , Cells, Cultured , Central Nervous System Agents/administration & dosage , Central Nervous System Agents/metabolism , Dinoprostone/administration & dosage , Female , Glutamic Acid/metabolism , Interleukin-6/metabolism , Intracellular Space/drug effects , Intracellular Space/metabolism , Lipopolysaccharides/toxicity , Male , Neuroglia/drug effects , Neuroglia/metabolism , Neurons/drug effects , Neurons/metabolism , Organum Vasculosum/drug effects , Preoptic Area/drug effects , Rats, Wistar , Synaptic Transmission/drug effects , Synaptic Transmission/physiology , Tumor Necrosis Factor-alpha/metabolism , gamma-Aminobutyric Acid/metabolism
10.
Phys Rev Lett ; 115(10): 102503, 2015 Sep 04.
Article in English | MEDLINE | ID: mdl-26382674

ABSTRACT

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.

11.
Phys Rev Lett ; 115(6): 062502, 2015 Aug 07.
Article in English | MEDLINE | ID: mdl-26296113

ABSTRACT

Total absorption spectroscopy is used to investigate the ß-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.

12.
Opt Lett ; 39(22): 6498-500, 2014 Nov 15.
Article in English | MEDLINE | ID: mdl-25490503

ABSTRACT

Selection of the fundamental mode of an active large mode area "ribbon" fiber laser with core dimensions of 107.8 µm by 8.3 µm was produced by a transmitting Bragg grating (TBG) in a free-space resonator. The multimode performance of the original laser was characterized to have an M2 of 11.3 with an absorbed power slope efficiency of 76%. With the TBG aligned to provide maximum diffraction efficiency for the fundamental mode, the M2 improved to 1.45 at an absorbed power slope efficiency of 54% and enhanced the brightness by 5.1 times.

13.
Phys Rev Lett ; 110(2): 022501, 2013 Jan 11.
Article in English | MEDLINE | ID: mdl-23383895

ABSTRACT

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.

14.
Emerg Med Int ; 2012: 108129, 2012.
Article in English | MEDLINE | ID: mdl-23243508

ABSTRACT

This paper reports on the application of full-body radiography to nontraumatic emergency situations. The Lodox Statscan is an X-ray machine capable of imaging the entire body in 13 seconds using linear slit scanning radiography (LSSR). Nontraumatic emergency applications in ventriculoperitoneal (VP) shunt visualisation, emergency room arteriography (ERA), detection of foreign bodies, and paediatric emergency imaging are presented. Reports show that the fast, full-body, and low-dose scanning capabilities of the Lodox system make it well suited to these applications, with the same or better image quality, faster processing times, and lower dose to patients. In particular, the large format scans allowing visualisation of a greater area of anatomy make it well suited to VP shunt monitoring, ERA, and the detection of foreign bodies. Whilst more studies are required, it can be concluded that the Lodox Statscan has the potential for widespread use in these and other nontraumatic emergency radiology applications.

15.
Appl Radiat Isot ; 68(4-5): 643-6, 2010.
Article in English | MEDLINE | ID: mdl-20096595

ABSTRACT

In 2002, an innovative neutron time-of-flight facility started operation at CERN: n_TOF. The main characteristics that make the new facility unique are the high instantaneous neutron flux, high resolution and wide energy range. Combined with state-of-the-art detectors and data acquisition system, these features have allowed to collect high accuracy neutron cross-section data on a variety of isotopes, many of which radioactive, of interest for Nuclear Astrophysics and for applications to advanced reactor technologies. A review of the most important results on capture and fission reactions obtained so far at n_TOF is presented, together with plans for new measurements related to nuclear industry.


Subject(s)
Neutron Capture Therapy/instrumentation , Neutron Capture Therapy/methods , Nuclear Reactors , Equipment Design , Equipment Failure Analysis , Neutrons , Reproducibility of Results , Sensitivity and Specificity
17.
Phys Rev Lett ; 93(16): 161103, 2004 Oct 15.
Article in English | MEDLINE | ID: mdl-15524972

ABSTRACT

The151Sm(n,gamma)152Sm cross section has been measured at the spallation neutron facility n_TOF at CERN in the energy range from 1 eV to 1 MeV. The new facility combines excellent resolution in neutron time-of-flight, low repetition rates, and an unsurpassed instantaneous luminosity, resulting in rather favorable signal/background ratios. The 151Sm cross section is of importance for characterizing neutron capture nucleosynthesis in asymptotic giant branch stars. At a thermal energy of kT=30 keV the Maxwellian averaged cross section of this unstable isotope (t(1/2)=93 yr) was determined to be 3100+/-160 mb, significantly larger than theoretical predictions.

18.
Phys Rev Lett ; 92(23): 232501, 2004 Jun 11.
Article in English | MEDLINE | ID: mdl-15245152

ABSTRACT

A novel method of deducing the deformation of the N=Z nucleus 76Sr is presented. It is based on the comparison of the experimental Gamow-Teller strength distribution B(GT) from its beta decay with the results of quasi-random-phase approximation calculations. This method confirms previous indications of the strong prolate deformation of this nucleus in a totally independent way. The measurement has been carried out with a large total absorption gamma spectrometer, "Lucrecia," newly installed at CERN-ISOLDE.

19.
J Radiol ; 85(4 Pt 1): 375-80, 2004 Apr.
Article in French | MEDLINE | ID: mdl-15213647

ABSTRACT

PURPOSE: To compare low-dose protocols using either reduction of the tension (kV) or reduction of the intensity (mAs) at abdominal CT imaging, with reference to image quality. MATERIALS AND METHODS: Fifty adult patients, weighing less than 55 kg, were prospectively included among patients referred for abdominal CT examination when the protocol required a noncontrast study. The images obtained with the standard protocol (120 kV, 200 mAs) were compared to 4 additional test images, two obtained with low intensity (120 kV, 100 mAs) and two obtained with low tension (100 kV, 200 mAs). Two senior radiologists blindly reviewed all images using both subjective (itemized list) and objective criteria (measure of standard deviation for density measurements obtained of the liver parenchyma). RESULTS: The image quality of the low kV protocol was better than the image quality of the low mAs protocol for both subjective and objective criteria. CONCLUSION: For abdominal CT imaging of standard to thin adult patients or children, dose reduction using a low kV protocol may be an alternative to a protocol using a low intensity. This can easily be implemented and can be used in conjunction with a dose reducing software.


Subject(s)
Tomography, X-Ray Computed/methods , Abdomen , Adult , Humans , Prospective Studies , Radiation Dosage , Reproducibility of Results
20.
Int J Clin Pract ; 58(3): 244-50, 2004 Mar.
Article in English | MEDLINE | ID: mdl-15117090

ABSTRACT

This randomised, double-blind, placebo-controlled, parallel-group study compared the efficacy and tolerability of lumiracoxib (a novel COX-2 selective inhibitor) with rofecoxib, celecoxib and placebo in patients with moderate-to-severe post-operative dental pain. Following third molar extraction, patients received single oral doses of lumiracoxib 400 mg, rofecoxib 50 mg, celecoxib 200 mg or placebo (n = 355). Additional patients from a similar study, assigned to lumiracoxib, rofecoxib or placebo (n = 155), were included for analysis of the primary variable, Summed Pain Intensity Difference over the first 8 h post dose (SPID-8). For SPID-8, lumiracoxib was superior to rofecoxib (p < 0.05), celecoxib (p < 0.001) and placebo (p < 0.001). Lumiracoxib demonstrated the fastest onset of analgesia and the longest time to rescue medication use. Patient global evaluation of lumiracoxib was comparable to rofecoxib and superior to celecoxib and placebo. All treatments were well tolerated. Lumiracoxib 400 mg provides rapid, effective and sustained relief of post-operative dental pain, comparable or superior to rofecoxib.


Subject(s)
Cyclooxygenase Inhibitors/therapeutic use , Organic Chemicals/therapeutic use , Pain, Postoperative/drug therapy , Tooth Extraction , Adolescent , Adult , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Celecoxib , Diclofenac/analogs & derivatives , Double-Blind Method , Female , Humans , Lactones/therapeutic use , Male , Molar, Third/surgery , Pyrazoles , Sulfonamides/therapeutic use , Sulfones , Treatment Outcome
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