We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure [email protected]
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Laser-driven neutron sources are routinely produced by the interaction of laser-accelerated protons with a converter. They present complementary characteristics to those of conventional accelerator-based neutron sources (e.g. short pulse durations, enabling novel applications like radiography). We present here results from an experiment aimed at performing a global characterization of the neutrons produced using the Titan laser at the Jupiter Laser Facility (Livermore, USA), where protons were accelerated from 23 $\mathrm {\mu }$m thick plastic targets and directed onto a LiF converter to produce neutrons. For this purpose, several diagnostics were used to measure these neutron emissions, such as CR-39, activation foils, time-of-flight detectors and direct measurement of $^7{\rm Be}$ residual activity in the LiF converters. The use of these different, independently operating diagnostics enables comparison of the various measurements performed to provide a robust characterization. These measurements led to a neutron yield of $2.0\times 10^{9}$ neutrons per shot with a modest angular dependence, close to that simulated.
Background: Brain tumors present unique challenges to patient and family quality of life (QOL). Cognitive dysfunction is common and functionally limiting, with no established treatments. These studies evaluate feasibility and preliminary efficacy of behavioral interventions developed for neuro-oncology patients. Study 1: A randomized controlled trial (N=25 primary brain tumor patients) compared an adapted version of Goal Management Training (GMT, a neuroscience-based integration of mindfulness and strategy training) and a newly-designed supportive psychoeducational intervention (Brain Health Program, BHP) to standard of care. Each intervention comprised 8 individual sessions and at-home practice between sessions. GMT patients’ executive functions improved immediately (p=.077, d=1.13), with maintenance at 4-month follow-up (p=.046, d=1.09). Both intervention groups reported improvements in everyday cognitive functioning immediately (p=.049; d’s GMT=0.43, BHP=0.79) and at follow-up (p=.001; d’s GMT=0.22, BHP=1.01). BHP patients also reported improved mood (p’s=.026 & .012, d’s=0.61 & 0.62). Study 2: Following a needs assessment about cognitive concerns and QOL in brain metastases patients (N=109) and caregivers (N=31), we developed a novel, brief (3 sessions + homework) Cognitive Support Program to provide education and strategy-training in key areas of concern: executive functions, memory, and communication. Options include caregiver co-training, and in-person or web-based delivery. Preliminary data from a pilot trial in progress demonstrate objective and subjective improvements. Conclusions: Cognitive rehabilitation may be a feasible and effective option for primary or metastatic brain tumor patients, addressing a need that is largely unmet in standard cancer care. Further development and larger trials appear warranted, with capacity for remote delivery recommended.
Objectives: Chemotherapy has adverse effects on cognitive performance in women treated for breast cancer, but less is known about the period before chemotherapy. Studies have focused on mean level of performance, yet there is increasing recognition that variability in performance within an individual is also an important behavioral indicator of cognitive functioning and underlying neural integrity. Methods: We examined intraindividual variability (IIV) before chemotherapy and surgery in women diagnosed with breast cancer (n=31), and a healthy control group matched on age and education (n=25). IIV was calculated across trials of a computerized Stroop task, including an examination of the slowest and fastest trials of reaction time (RT) responses. Results: The groups were equivalent on overall accuracy and speed, and participants in both groups were less accurate and slower on incongruent trials compared with congruent trials. However, women with breast cancer became more variable with increased task difficulty relative to healthy controls. Among the slowest RT responses, women with breast cancer were significantly more variable than healthy controls on incongruent trials. This suggests that a specific variability-producing process (e.g., attentional lapses) occurs in task conditions that require executive control (e.g., incongruent trials). Conclusions: Results are consistent with other evidence of executive dysfunction among women treated for breast cancer. These findings highlight the importance of pretreatment assessment and show that variability in performance provides information about cognition that measures of central tendency do not. (JINS, 2016, 23, 1–10)
This paper celebrates the centenary of Queen Mary College’s involvement in aeronautics, a celebration with a unique distinction since it was this College’s immediate forebear which was the first British higher education institution to begin teaching and research in this subject. Thus the emphasis is on the early years from 1907 until the 1950s, a period ripe for recording before it recedes beyond living memory, but also the period during which the degree course in aeronautical engineering became firmly established and its parent Department acquired its reputation for research. Section 2.0 gives a brief history of the College’s origins in the East London College. Subsequent sections deal with the foundation of the aeronautical laboratory there, from which the aeronautical department grew, and the activities of the two men who led these developments, A.P. Thurston and N.A.V. Tonnstein who changed his name to Piercy.
Jean d'Ockeghem's preeminence among the composers of his generation seems unassailable. Two decisive inflections were introduced into the Ockeghem reception around the middle of the sixteenth century. Both brought about significant change, but in very different ways. One reflects a very practical strain within the Ockeghem reception, affecting which music is available and how it is read; the other is a more subtle change within the forces that have an impact on how the music is appreciated. The principal hero in early Ockeghem scholarship is August Wilhelm Ambros, whose command of musical sources expanded the available corpus of Ockeghem's works from the four pieces that were known in the eighteenth century to twenty-one. More importantly, he focused intensely on their musicality, rather than on their technique. One of the most puzzling characterizations of Ockeghem's music is its portrayal as a mystical expression of pietism.
Jean d'Ockeghem is praised widely for his graciousness, his Christian virtues, and his skill as a singer. Jean Molinet, who singles out the music of Gilles Binchois, Antoine Busnoys, Guillaume Du Fay, and Ockeghem as the best of its day, lists Ockeghem as the first among these masters. The role of imitation in Ockeghem's music has been the object of a great deal of commentary. Ockeghem's approach to melody appears to be among the most elusive aspects of his music, to judge from the level of subjectivity that permeates various attempts to describe his melodic design. Ockeghem's textures gain clarity from the sense of unification provided by imitation, but the imprecise character of that imitation often leaves the listener wondering if it is adequately real to foster a genuine perception of such unity. Long, serpentine melodies abound in Ockeghem's music, inevitably resulting in a sense of unpredictable meandering.
Studies assessing cognitive functioning in women treated for breast cancer have used primarily standardized neuropsychological tests and examined accuracy and/or reaction time as outcome measures: they have been inconsistent in identifying the cognitive domains affected and the severity of deficits. In other contexts of neural development and disorders, measures of Intra-individual variability (IIV) have proven useful in identifying subtleties in performance deficits that are not captured by measures of central tendency. This article presents proof of concept that assessing IIV may also increase understanding of the cognitive effects of cancer treatment. We analyzed mean accuracy and reaction time, as well as IIV from 65 women with breast cancer and 28 age and education matched controls who performed the Conner's Continuous Performance Test, a “Go-NoGo” task. Although there were no significant differences between groups using measures of central tendency, there was a group × inter-stimulus interval (ISI) interaction for IIV Dispersion (p < .001). Patient Dispersion was more variable at shorter ISI than controls and less variable at long ISI, suggesting greater sensitivity to presentation speed. Interpretation of IIV differences requires further investigation. Our results suggest that future studies would benefit from designs that allow analysis of IIV measures in studies assessing cognition in cancer survivors. (JINS, 2014, 20, 1–11)
We suggest that the diffuse interstellar bands (DIBs) are absorption lines arising from electronic transitions in molecular clusters primarily composed of a single molecule, atom, or ion (“seed”), embedded in a single-layer shell of H2 molecules (Bernstein et al. 2013). We refer to these clusters as CHCs (Contaminated H2 Clusters). CHCs arise from cm-sized, dirty H2 ice balls, called CHIMPs (Contaminated H2 Ice Macro-Particles), formed in cold, dense, Giant Molecular Clouds (GMCs), and later released into the interstellar medium (ISM) upon GMC disruption. Absorption by the CHIMP of a UV photon releases CHCs. CHCs produce DIBs when they absorb optical photons. When this occurs, the absorbed photon energy disrupts the CHC.
We propose that the diffuse interstellar bands (DIBs) arise from absorption lines of electronic transitions in molecular clusters primarily composed of a single molecule, atom, or ion (“seed”), embedded in a single-layer shell of H2 molecules (Bernstein et al. 2013). Less abundant variants of the cluster, including two seed molecules and/or a two-layer shell of H2 molecules may also occur. The lines are broadened, blended, and wavelength-shifted by interactions between the seed and surrounding H2 shell. We refer to these clusters as CHCs (Contaminated H2 Clusters). CHC spectroscopy matches the diversity of observed DIB spectral profiles, and provides good fits to several DIB profiles based on a rotational temperature of 10 K. CHCs arise from ~cm-sized, dirty H2 ice balls, called CHIMPs (Contaminated H2 Ice Macro-Particles), formed in cold, dense, Giant Molecular Clouds (GMCs), and later released into the interstellar medium (ISM) upon GMC disruption. Attractive interactions, arising from Van der Waals and ion-induced dipole potentials, between the seeds and H2 molecules enable CHIMPs to attain cm-sized dimensions. When an ultraviolet (UV) photon is absorbed in the outer layer of a CHIMP, it heats the icy matrix and expels CHCs into the ISM. While CHCs are quickly destroyed by absorbing UV photons, they are replenished by the slowly eroding CHIMPs. Since CHCs require UV photons for their release, they are most abundant at, but not limited to, the edges of UV-opaque molecular clouds, consistent with the observed, preferred location of DIBs. An inherent property of CHCs, which can be characterized as nanometer size, spinning, dipolar dust grains, is that they emit in the radio-frequency region. Thus, CHCs offer a natural explanation to the anomalous microwave emission (AME) feature in the ~10-100 GHz spectral region.
Oceanic and coastal bioluminescence in surface waters, in many instances, is produced by microscopic dinoflagellates. Their light emission is usually observed at a maximum during the night hours and markedly inhibited during the day. This diel periodicity has never been observed in situ for identified species and never before in heterotrophic Protoperidinium dinoflagellates. Pronounced differences in stimulable bioluminescence measured with bathyphotometers in Vestfjord, Norway in September 1990 correlated with simultaneous ship-board laboratory experiments. Cells of both the photosynthetic Ceratium fusus and heterotrophic Protoperidinium curtipes showed a pronounced inhibition of bioluminescence during the day and maximum bioluminescence at night.
A 3-year-old boy developed acute pulmonary edema following 6 months of recurrent fevers and thrombocytosis. Echocardiography demonstrated moderate-to-severe insufficiency of both mitral and aortic valves. Angiography and intravascular ultrasound were used to diagnose this unusual presentation of Takayasu's arteritis. To the best of our knowledge, this is the first histological demonstration of acute and chronic inflammatory changes in the mitral valve in these circumstances.
Alumina-based refractory materials are extensively used in high-temperature industrial applications, such as for linings in waste and other incinerators. The existence of porosity and material inhomogeneities can promote chemical degradation due to molten slag penetration, while impacting solid or liquid feedstock can cause erosive-wear damage. Previous research has successfully used single laser energy sources to alter the surface properties of similar ceramics, with emphasis on sealing porosity and enhancing degradation resistance. However, this process has resulted in some solidification cracking at the surface due to large temperature gradients developed during processing. In the present, ongoing work, the surface of the refractory ceramic is modified by combining two laser energy sources to control the thermal gradients and cooling rates, with the objective of eliminating crack formation. The surface morphology and microstructures of the laser-treated areas are analyzed. This paper presents some initial results from the programme.
Our understanding of materials phenomena is based on a hierarchy of physical descriptions spanning the space-time regimes of electrons, atoms, and matter and given by the theories of quantum mechanics, statistical mechanics, and continuum mechanics. The pioneering work of Clementi and co-workers provides a lucid example of the traditional approach to incorporating multiscale phenomena associated with these three mechanics. Using quantum mechanics, they evaluated the interactions of several water molecules. From this data base, they created an empirical potential for use in atomistic mechanics and evaluated the viscosity of water. From this computed viscosity, they performed a fluid-dynamics simulation to predict the tidal circulation in Buzzard's Bay. This is a powerful example of the sequential coupling of length and time scales: a series of calculations is used as input to the next rung up the length/time-scale ladder.
We have developed an alloy of silicon rich amorphous silicon nitride as a linkable interlevel metal dielectric. This material is thermally stable through a heat treatment of 425°C for 30 minutes. The hydrogen content remains at approximately 21 at.%, even after this heat treatment. The breakdown potential is 1.9 × 106 V/cm at which point a metallic filament link forms between the metal contacts. The index of refraction is 2.43 and the HF permittivity is 9 Co- One important property is its ability to store polarized charge like an electret. This feature could allow it to be used in memory applications like MNOS. The alloy is also photoconductive with a response time of less than 5 μs, allowing it to be used as part of an optically sensitive circuit element.
Thin films of the electrically conducting polymer, poly(3-hexylthiophene) (P3HT), were developed as sensors for hydrazine vapor at the part-per-billion level. The P3HT films were fabricated by a spin coating technique onto quartz substrates incorporating gold interdigitated electrodes, and were rendered conductive by doping with an NOPF6 solution. The sensors respond strongly and instantaneously to hydrazine concentrations as low as 1 part-per-billion with a measurement accuracy of ±20%. In addition, the sensors exhibited excellent environmental stability, long shelf life, and good interference rejection.