Needle core biopsy is considered the histological diagnostic method of choice for screen-detected breast lesions. Although the majority are definitively diagnosed as normal, benign, or malignant, ...approximately 7% are categorised as B3, of uncertain malignant potential. These include a wide range of lesions with different risks of associated malignancy from <2% to approaching 40% from literature review in UK practice. Historically, these have typically been surgically excised as a diagnostic procedure but the majority are then proven to be benign. An alternative approach, for many of these lesions, is thorough sampling/excision by vacuum-assisted biopsy techniques to exclude the presence of co-existing carcinoma. This would potentially reduce the benign open biopsy rate whilst maintaining accuracy of cancer diagnosis. A group from the Radiology, Surgery, and Pathology NHS Breast Screening Programme Co-ordinating Committees and an additional co-opted expert were charged with review and development of guidelines for the clinical management of B3 lesions. The guidelines reflect suggested practice as stated by the NHS Breast Screening Programme and approved by the Royal College of Radiologists.
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We present an account of the current status of the theoretical treatment of inclusive (
d
,
p
) reactions in the breakup-fusion formalism, pointing to some applications and making the connection ...with current experimental capabilities. Three independent implementations of the reaction formalism have been recently developed, making use of different numerical strategies. The codes also originally relied on two different but equivalent representations, namely the prior (Udagawa-Tamura, UT) and the post (Ichimura-Austern-Vincent, IAV) representations. The different implementations have been benchmarked for the first time, and then applied to the Ca isotopic chain. The neutron-Ca propagator is described in the Dispersive Optical Model (DOM) framework, and the interplay between elastic breakup (EB) and non-elastic breakup (NEB) is studied for three Ca isotopes at two different bombarding energies. The accuracy of the description of different reaction observables is assessed by comparing with experimental data of (
d
,
p
) on
40,48
Ca. We discuss the predictions of the model for the extreme case of an isotope (
60
Ca) currently unavailable experimentally, though possibly available in future facilities (nominally within production reach at FRIB). We explore the use of (
d
,
p
) reactions as surrogates for
(
n
,
γ
)
processes, by using the formalism to describe the compound nucleus formation in a
(
d
,
p
γ
)
reaction as a function of excitation energy, spin, and parity. The subsequent decay is then computed within a Hauser-Feshbach formalism. Comparisons between the
(
d
,
p
γ
)
and
(
n
,
γ
)
induced gamma decay spectra are discussed to inform efforts to infer neutron captures from
(
d
,
p
γ
)
reactions. Finally, we identify areas of opportunity for future developments, and discuss a possible path toward a predictive reaction theory.
Yellowtail kingfish (
Seriola lalandi) are farmed in sea cages in South Australian waters and exposed to seasonal variations in water temperature. The temperature variations, ranging from 10 to 24
...°C, influence feed intake and on-farm feeding practices. Sub-adult yellowtail kingfish are fed twice daily in summer while feeding in winter may be reduced to once every second day. Lower winter water temperatures increase gut transit times which may lead to a condition known as winter syndrome. This syndrome causes an enteritis response in yellowtail kingfish and reduces farm productivity. The impact of water temperature on gut transit time, nutrient digestibility and protease and lipase enzyme activities in yellowtail kingfish (2.12
±0.03 and 2.77
±
0.03
kg live weight in summer and winter respectively) was investigated at summer and winter water temperatures; 20.8
±
0.4
°C and 12.6
±
0.1
°C respectively, using observations made on dissected fish and detection of the passage of dietary markers. Water temperature had a significant effect on gut transit time, with visual observations demonstrating that at summer water temperatures it takes 12–16
h for all digesta to be voided from the fish compared to 36–48
h at winter temperatures. Temperature did not have a significant effect on the dietary nutrient apparent digestibility coefficients (ADC, %) although there was a numerical tendency for nutrient ADC to be higher in the posterior intestine at summer water temperatures: 46% vs. 35% for dry matter; 70% vs. 67% for protein; 66% vs. 58% for fat; and 70% vs. 63% for energy. Nutrient digestibility did not differ significantly between the anterior and posterior intestinal sections; however, the ADC values were consistently higher in posterior intestine. Protease activity was significantly higher in the posterior intestine and there was also a numerical, but not significant, increase in protease and lipase activities in the anterior section of the intestine during winter. Lipase activity was significantly higher in the anterior intestine during summer, when compared to the posterior section, and numerically higher in this section during winter. In winter it was found that a greater proportion of nutrient digestion occurred in the stomach, pyloric caeca and anterior intestine when compared to summer. This was thought to be due to the slower gut motility and higher enzyme activities observed during winter. Even though gut transit time was slower in winter, the lower water temperature also resulted in nutrient digestibility that was numerically lower.
The neutron-capture reaction plays a critical role in the synthesis of the elements in stars and is important for societal applications including nuclear power generation and stockpile-stewardship ...science. However, it is difficult-if not impossible-to directly measure neutron capture cross sections for the exotic, short-lived nuclei that participate in these processes. In this Letter we demonstrate a new technique which can be used to indirectly determine neutron-capture cross sections for exotic systems. This technique makes use of the (d,p) transfer reaction, which has long been used as a tool to study the structure of nuclei. Recent advances in reaction theory, together with data collected using this reaction, enable the determination of neutron-capture cross sections for short-lived nuclei. A benchmark study of the ^{95}Mo(d,p) reaction is presented, which illustrates the approach and provides guidance for future applications of the method with short-lived isotopes produced at rare isotope accelerators.
•Sediments were collected in an area naturally enriched in LREEs.•Microscale tests were used to assess the ecotoxicity of sediment.•Ecotoxicological protocols varied in their ability to mobilize REEs ...from sediments.•Different REE availability and toxicity depended on sediment composition.•Sediment characteristics likely contributed to observed ecotoxicity.
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Rare earth elements (REEs) disperse from indigenous rocks to the environment, thus making sediments one of the major sinks and sources of metal pollution. The emerging use of REEs and the subsequent opening of new mining areas may contribute to their release into surrounding ecosystems. For this reason, this study was performed in a natural area with geological material abundant in ferrocarbonatites and light REE. The aim of this work was to assess the natural REE availability and (eco)toxicity in freshwater sediments. Sediments showed high REE concentrations in samples with fine grain size fractions, and low in organic-rich sediments. The enrichment in LREE was mostly from rocks and the obtained enrichment factors (EF) confirmed that the sediments are not anthropogenically polluted. To assess REE availability and ecotoxicity, four toxicity tests were performed. REEs measured as the dissolved concentration in the test media were very low compared to the potentially available total REE in sediments and showed positive or negative correlations with fine or coarse grain sizes, respectively, and positive correlations with the content in Mg, Fe and Al. In tests performed in media supplemented with salts, the availability of REEs decreased considerably. Only some toxic effects could be linked to the REE contents in the ostracodtox and luminotox tests. However, measurement of toxicity could be influenced by the sediment properties and lead to a potential overestimation of ecotoxicity if only REE are regarded. Our study reveals that the physicochemical properties of sediments are a key factor controlling both REE availability and toxicity, whereas the determination of REE effects from toxicity tests using liquid media with salt addition will decrease REE availability and could mask toxic effects. Our findings provide new knowledge about REE behaviour in sediments and are a starting point for understanding potential REE pollution around prospective mining areas.
Atomic nuclei have a shell structure in which nuclei with ‘magic numbers’ of neutrons and protons are analogous to the noble gases in atomic physics. Only ten nuclei with the standard magic numbers ...of both neutrons and protons have so far been observed. The nuclear shell model is founded on the precept that neutrons and protons can move as independent particles in orbitals with discrete quantum numbers, subject to a mean field generated by all the other nucleons. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important for a fundamental understanding of nuclear structure and nucleosynthesis (for example the r-process, which is responsible for the production of about half of the heavy elements). However, as a result of their short lifetimes, there is a paucity of knowledge about the nature of single-particle states outside exotic doubly magic nuclei. Here we measure the single-particle character of the levels in 133Sn that lie outside the double shell closure present at the short-lived nucleus 132Sn. We use an inverse kinematics technique that involves the transfer of a single nucleon to the nucleus. The purity of the measured single-particle states clearly illustrates the magic nature of 132Sn.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The study of the nuclear physics properties which govern energy generation and nucleosynthesis in the astrophysical phenomena we observe in the universe is crucial to understanding how these objects ...behave and how the chemical history of the universe evolved to its present state. The low cross sections and short nuclear lifetimes involved in many of these reactions make their experimental determination challenging, requiring developments in beams and instrumentation. A selection of developments in nuclear astrophysics instrumentation is discussed, using as examples projects involving the nuclear astrophysics group at Oak Ridge National Laboratory. These developments will be key to the instrumentation necessary to fully exploit nuclear astrophysics opportunities at the Facility for Rare Isotope Beams which is currently under construction.
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