Frustration, defined as a competition between interactions such that not all of them can be satisfied, is important in systems ranging from neural networks to structural glasses. Geometrical ...frustration, which arises from the topology of a well-ordered structure rather than from disorder, has recently become a topic of considerable interest. In particular, geometrical frustration among spins in magnetic materials can lead to exotic low-temperature states, including 'spin ice', in which the local moments mimic the frustration of hydrogen ion positions in frozen water. Here we report an artificial geometrically frustrated magnet based on an array of lithographically fabricated single-domain ferromagnetic islands. The islands are arranged such that the dipole interactions create a two-dimensional analogue to spin ice. Images of the magnetic moments of individual elements in this correlated system allow us to study the local accommodation of frustration. We see both ice-like short-range correlations and an absence of long-range correlations, behaviour which is strikingly similar to the low-temperature state of spin ice. These results demonstrate that artificial frustrated magnets can provide an uncharted arena in which the physics of frustration can be directly visualized.
Studies using magnetic resonance imaging to assess lumbar multifidus cross-sectional area frequently utilize T1 or T2-weighted sequences, but seldom provide the rationale for their sequence choice. ...However, technical considerations between their acquisition protocols could impact on the ability to assess lumbar multifidus anatomy or its fat/muscle distinction. Our objectives were to examine the concurrent validity of lumbar multifidus morphology measures of T2 compared to T1-weighted sequences, and to assess the reliability of repeated lumbar multifidus measures.
The lumbar multifidus total cross-sectional area of 45 patients was measured bilaterally at L4 and L5, with histogram analysis determining the muscle/fat threshold values per muscle. Images were later re-randomized and re-assessed for intra-rater reliability. Matched images were visually rated for consistency of outlining between both image sequences. Bland-Altman bias, limits of agreement, and plots were calculated for differences in total cross-sectional area and percentage fat between and within sequences, and intra-rater reliability analysed.
T1-weighted total cross-sectional area measures were systematically larger than T2 (0.2 cm2), with limits of agreement <±10% at both spinal levels. For percentage fat, no systematic bias occurred, but limits of agreement approached ±15%. Visually, muscle outlining was consistent between sequences, with substantial mismatches occurring in <5% of cases. Intra-rater reliability was excellent (ICC: 0.981-0.998); with bias and limits of agreement less than 1% and ±5%, respectively.
Total cross-sectional area measures and outlining of muscle boundaries were consistent between sequences, and intra-rater reliability for total cross-sectional area and percentage fat was high indicating that either MRI sequence could be used interchangeably for this purpose. However, further studies comparing the accuracy of various methods for distinguishing fat from muscle are recommended.
Summary Background The need for timely and reliable information about global health resource flows to low-income and middle-income countries is widely recognised. We aimed to provide a comprehensive ...assessment of development assistance for health (DAH) from 1990 to 2007. Methods We defined DAH as all flows for health from public and private institutions whose primary purpose is to provide development assistance to low-income and middle-income countries. We used several data sources to measure the yearly volume of DAH in 2007 US$, and created an integrated project database to examine the composition of this assistance by recipient country. Findings DAH grew from $5·6 billion in 1990 to $21·8 billion in 2007. The proportion of DAH channelled via UN agencies and development banks decreased from 1990 to 2007, whereas the Global Fund to Fight AIDS, Tuberculosis and Malaria, the Global Alliance for Vaccines and Immunization (GAVI), and non-governmental organisations became the conduit for an increasing share of DAH. DAH has risen sharply since 2002 because of increases in public funding, especially from the USA, and on the private side, from increased philanthropic donations and in-kind contributions from corporate donors. Of the $14·5 billion DAH in 2007 for which project-level information was available, $5·1 billion was for HIV/AIDS, compared with $0·7 billion for tuberculosis, $0·8 billion for malaria, and $0·9 billion for health-sector support. Total DAH received by low-income and middle-income countries was positively correlated with burden of disease, whereas per head DAH was negatively correlated with per head gross domestic product. Interpretation This study documents the substantial rise of resources for global health in recent years. Although the rise in DAH has resulted in increased funds for HIV/AIDS, other areas of global health have also expanded. The influx of funds has been accompanied by major changes in the institutional landscape of global health, with global health initiatives such as the Global Fund and GAVI having a central role in mobilising and channelling global health funds. Funding Bill & Melinda Gates Foundation.
Environmental sustainability and human cultural sustainability are inextricably linked. Reversing damaging human impact on the global environment is ultimately a cultural question, and as with ...politics, the answers are often profoundly local. Cultural Sustainabilities presents twenty-three essays by musicologists and ethnomusicologists, anthropologists, folklorists, ethnographers, documentary filmmakers, musicians, artists, and activists, each asking a particular question or presenting a specific local case study about cultural and environmental sustainability. Contributing to the environmental humanities, the authors embrace and even celebrate human engagement with ecosystems, though with a profound sense of collective responsibility created by the emergence of the Anthropocene. Contributors: Aaron S. Allen, Michael B. Bakan, Robert Baron, Daniel Cavicchi, Timothy J. Cooley, Mark F. DeWitt, Barry Dornfeld, Thomas Faux, Burt Feintuch, Nancy Guy, Mary Hufford, Susan Hurley-Glowa, Patrick Hutchinson, Michelle Kisliuk, Pauleena M. MacDougall, Margarita Mazo, Dotan Nitzberg, Jennifer C. Post, Tom Rankin, Roshan Samtani, Jeffrey A. Summit, Jeff Todd Titon, Joshua Tucker, Rory Turner, Denise Von Glahn, and Thomas Walker
Astrophysical observations indicate that dark matter constitutes most of the mass in our universe, but its nature remains unknown. Over the past decade, the Cryogenic Dark Matter Search (CDMS II) ...experiment has provided world-leading sensitivity for the direct detection of weakly interacting massive particle (WIMP) dark matter. The final exposure of our low-temperature germanium particle detectors at the Soudan Underground Laboratory yielded two candidate events, with an expected background of 0.9 ± 0.2 events. This is not statistically significant evidence for a WIMP signal. The combined CDMS II data place the strongest constraints on the WIMP-nucleon spin-independent scattering cross section for a wide range of WIMP masses and exclude new parameter space in inelastic dark matter models.
Few studies have explored outdoor therapy when facilitated by clinical psychologists within an inpatient mental health service. In the present study, outdoor psychology sessions were introduced after ...service users (SUs) expressed a desire to return to face-to-face working during the COVID-19 pandemic. This study aimed to explore SUs' and clinical psychologists' perspectives on the feasibility of conducting outdoor therapy within the service. A mixed-method approach was underpinned by critical realist philosophy. Three psychologists maintained reflective diaries following outdoor therapy sessions with 16 SUs. A subsample of 14 SUs completed scales measuring therapeutic alliance and comfort during outdoor sessions. A subsample of eight SUs participated in semi-structured interviews. Data was analysed using descriptive statistics and thematic analysis. Quantitative and qualitative data demonstrated high SU satisfaction with therapeutic alliance and comfort outdoors. Six themes were identified: utilising a person-centred approach; the value of multi-disciplinary team support; enhancing therapeutic engagement; the benefits of time away from the ward; managing confidentiality; physical health and safety. This feasibility study demonstrated the introduction of outdoor psychology sessions within an inpatient mental health service to be a viable response to COVID-19. The findings suggest outdoor therapy can be an effective and safe mode of therapy, and can offset the challenges of indoor working, providing certain risk factors are considered and managed. The limitations of this study and implications for clinical practice are discussed. Further research is now required to support future integration into clinical practice.
A highly efficient, fully parallelized, fully relativistic, three-dimensional particle-in-cell model for simulating plasma and laser wakefield acceleration is described. The model is based on the ...quasi-static or frozen field approximation, which reduces a fully three-dimensional electromagnetic field solve and particle push to a two-dimensional field solve and particle push. This is done by calculating the plasma wake assuming that the drive beam and/or laser does not evolve during the time it takes for it to pass a plasma particle. The complete electromagnetic fields of the plasma wake and its associated index of refraction are then used to evolve the drive beam and/or laser using very large time steps. This algorithm reduces the computational time by 2–3 orders of magnitude. Comparison between the new algorithm and conventional fully explicit models (OSIRIS) is presented. The agreement is excellent for problems of interest. Direction for future work is also presented.
Purpose
Through screening and HPV vaccination, cervical cancer can mostly be prevented or detected very early, before symptoms develop. However, cervical cancer persists, and many women are diagnosed ...at advanced stages. Little is known about the degree to which U.S. women may begin their diagnostic workup for cervical cancer in Emergency Departments (ED). We sought to quantify the proportion of women presenting symptomatically in the ED prior to their diagnosis with cervical cancer and to describe their characteristics and outcomes.
Methods
We identified women diagnosed from 2006 to 2017 with cervical cancer in the California Cancer Registry. We linked this cohort to statewide ED discharge records to determine ED use and symptoms present at the encounter. Multivariable logistic regression models examined associations with ED use and multivariable Cox proportional hazards regression models examined associations with survival.
Results
Of the more than 16,000 women with cervical cancer in the study cohort, 28% presented symptomatically in the ED prior to diagnosis. Those presenting symptomatically were more likely to have public (odds ratio OR 1.16; 95% confidence interval CI 1.06–1.27) or no insurance (OR 4.81; CI 4.06–5.71) (vs. private), low socioeconomic status (SES) (OR 1.76; CI 1.52–2.04), late-stage disease (OR 5.29; CI 4.70–5.96), and had a 37% increased risk of death (CI 1.28–1.46).
Conclusion
Nearly a third of women with cervical cancer presented symptomatically, outside of a primary care setting, suggesting that many women, especially those with low SES, may not be benefiting from screening or healthcare following abnormal results.
We examine the operation and performance of an automated heat-capacity measurement system manufactured by Quantum Design (QD). QD’s physical properties measurement system (PPMS) employs a ...thermal-relaxation calorimeter that operates in the temperature range of 1.8–395 K. The accuracy of the PPMS specific-heat data is determined here by comparing data measured on copper and synthetic sapphire samples with standard literature values. The system exhibits an overall accuracy of better than 1% for temperatures between 100 and 300 K, while the accuracy diminishes at lower temperatures. These data confirm that the system operates within the ±5% accuracy specified by QD. Measurements on gold samples with masses of 4.5 and 88 mg indicate that accuracy of ±3% or better can be achieved below 4 K by using samples with heat capacities that are half or greater than the calorimeter addenda heat capacity. The ability of a PPMS calorimeter to accurately measure sharp features in
C
p
(
T) near phase transitions is determined by measuring the specific heat in the vicinity of the first-order antiferromagnetic transition in Sm
2IrIn
8 (
T
0=14 K) and the second-order hidden order (HO) transition in URu
2Si
2 (
T
N
=17 K). While the PPMS measures
C
p
(
T) near the second-order transition accurately, it is unable to do so in the vicinity of the first-order transition. We show that the specific heat near a first-order transition can be determined from the PPMS-measured decay curves by using an alternate analytical approach. This correction is required because the latent heat liberated/absorbed at the transition results in temperature–decay curves that cannot be described by a single relaxation time constant. Lastly, we test the ability of the PPMS to measure the specific heat of Mg
11B
2, a superconductor of current interest to many research groups, that has an unusually strong field-dependent specific heat in the mixed state. At the critical temperature the discontinuity in the specific heat is nearly 15% lower than measurements made on the same sample using a semi-adiabatic calorimeter at Lawrence Berkeley National Laboratory.
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