Fault-tolerant control of an error-corrected qubit.

Quantum error correction protects fragile quantum information by encoding it into a larger quantum system1,2. These extra degrees of freedom enable the detection and correction of errors, but also increase the control complexity of the encoded logical qubit. Fault-tolerant circuits contain the spread of errors while controlling the logical qubit, and are essential for realizing error suppression in practice3-6. Although fault-tolerant design works in principle, it has not previously been demonstrated in an error-corrected physical system with native noise characteristics. Here we experimentally demonstrate fault-tolerant circuits for the preparation, measurement, rotation and stabilizer measurement of a Bacon-Shor logical qubit using 13 trapped ion qubits. When we compare these fault-tolerant protocols to non-fault-tolerant protocols, we see significant reductions in the error rates of the logical primitives in the presence of noise. The result of fault-tolerant design is an average state preparation and measurement error of 0.6 per cent and a Clifford gate error of 0.3 per cent after offline error correction. In addition, we prepare magic states with fidelities that exceed the distillation threshold7, demonstrating all of the key single-qubit ingredients required for universal fault-tolerant control. These results demonstrate that fault-tolerant circuits enable highly accurate logical primitives in current quantum systems. With improved two-qubit gates and the use of intermediate measurements, a stabilized logical qubit can be achieved.

Breast cancer survivorship and sexual dysfunction: a population-based cohort study.

BACKGROUND: Breast cancer is the most common non-skin cancer in women and an increasing number of people are living as breast cancer survivors. While the prognosis of breast cancer continues to improve, the rates of sexual dysfunction and the risk related to cancer treatments have not been well characterized in a population-based study. METHODS: We identified a cohort of 19,709 breast cancer survivors diagnosed between 1997 and 2017 from the Utah Cancer Registry, and 93,389 cancer-free women who were matched by age and birth state from the Utah Population Database. Sexual dysfunction diagnoses were identified through ICD-9 and ICD-10 codes from electronic medical records and statewide healthcare facilities data. Cox proportional hazard models were used to estimate hazard ratios for risk of sexual dysfunction. RESULTS: Breast cancer survivors were at higher risk of sexual dysfunction diagnosis (9.1% versus 6.9%, HR 1.60, 95% CI 1.51-1.70) compared to the general population. This risk increased 2.05-fold within 1 to 5 years after cancer diagnosis (95% CI 1.89-2.22) and 3.05-fold in individuals diagnosed with cancer at < 50 years of age (95% CI 2.65-3.51). Cancer treatments including endocrine therapy, chemotherapy and radiation therapy were associated with an increased risk of sexual dysfunction among breast cancer survivors. CONCLUSIONS: Risk of sexual dysfunction in breast cancer survivors is higher than in the general population, but may be underdiagnosed in the clinical setting. Health care professionals should be encouraged to address the topic of sexual health early on in the treatment of breast cancer, and routinely screen patients for symptoms of sexual dysfunction.

Surveillance Imaging with PET/CT and CT and/or MRI for Head and Neck Cancer and Mortality: A Population-based Study.

Background To the knowledge of the authors, no strong evidence supports surveillance imaging in patients with head and neck cancer (HNC). Purpose To investigate the association between surveillance imaging and mortality using a population-based study design with statewide cancer registry data, all-payer claims data, and health care facility data. Materials and Methods The retrospective population-based study identified patients with HNC diagnosed between January 2012 and December 2017. Current Procedural Terminology codes were used to search surveillance imaging procedures. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% CIs for mortality with adjustment for sex, ethnicity, age, health insurance status, cancer site, stage, and treatment. Results The study identified 1004 patients (mean age, 61 years ± 12 [SD]; 753 men), including 902 patients with squamous cell carcinoma (SCC) HNC and 102 patients with non-SCC. The effect of imaging on mortality among patients with SCC was not statistically significant when the entire sample was analyzed (HR, 0.76; 95% CI: 0.57, 1.02; P = .07). However, in stratified analyses by cancer stage, surveillance imaging was associated with lower mortality among patients with SCC for regionalized cancer stage (HR, 0.55; 95% CI: 0.36, 0.83; P = .005) and distant cancer stage (HR, 0.40; 95% CI: 0.19, 0.83; P = .01). Among patients with non-SCC, surveillance imaging was associated with lower mortality versus no surveillance imaging (HR, 0.19; 95% CI: 0.04, 0.94; P = .04). PET/CT was associated with lower mortality for patients with SCC (HR, 0.29; 95% CI: 0.09, 0.94; P = .04), and CT and/or MRI was associated with lower mortality for patients with non-SCC (HR, 0.11; 95% CI: 0.01, 0.94; P = .04). Conclusion Surveillance imaging was associated with lower mortality among patients with head and neck squamous cell carcinoma with regionalized or distant disease. The surveillance imaging protective association was observed up to 2 years after treatment completion. © RSNA, 2023 Supplemental material is available for this article. See also the editorial by Branstetter in this issue.

Contributions of cancer treatment, comorbidities, and obesity to aging-related disease risks among non-Hodgkin lymphoma survivors.

PURPOSE: It is unknown whether cancer treatment contributes more to long-term disease risk than lifestyle factors and comorbidities among B-cell non-Hodgkin lymphoma (B-NHL) survivors. METHODS: B-NHL survivors were identified in the Utah Cancer Registry from 1997 to 2015. Population attributable fractions (PAF) were calculated to assess the role of clinical and lifestyle factors for six cardiovascular, pulmonary, and renal diseases. RESULTS: Cancer treatment contributed to 11% of heart and pulmonary conditions and 14.1% of chronic kidney disease. Charlson Comorbidity Index (CCI) at baseline contributed to all six diseases with a range of 9.9% of heart disease to 26.5% of chronic kidney disease. High BMI at baseline contributed to 18.4% of congestive heart failure and 7.9% of pneumonia, while smoking contributed to 4.8% of COPD risk. CONCLUSION: Cancer treatment contributed more to heart disease, COPD, and chronic kidney disease than lifestyle factors and comorbidities among B-NHL survivors. High BMI at baseline contributed more to congestive heart failure and pneumonia than cancer treatment, whereas smoking at baseline was not a major contributor in this B-NHL survivor cohort. Baseline comorbidities consistently demonstrated high attributable risks for these diseases, demonstrating a strong association between preexisting comorbidities and aging-related disease risks.

Cardiovascular disease risk in long-term breast cancer survivors: A population-based cohort study.

BACKGROUND: Breast cancer survival is increasing, making late effects such as cardiovascular disease (CVD) more relevant. The purpose of this study was to evaluate incident CVD following breast cancer diagnosis among long-term survivors and to investigate possible risk factors for CVD. METHODS: A population-based cohort of 6641 breast cancer survivors diagnosed between 1997 and 2009 who survived at least 10 years was identified within the Utah Cancer Registry. In addition, 36,612 cancer-free women from the general population, matched by birth year and state, were identified within the Utah Population Database. Cox proportional hazards models were used to calculate CVD hazard ratios (HRs) for >10 to 15 and >15 years. RESULTS: Long-term breast cancer survivors had an increased risk of newly diagnosed diseases of the circulatory system (HR, 1.32; 99% confidence interval [CI], 1.00-1.75) from 10 to 15 years following cancer diagnosis compared with the general population. No increased CVD risks were observed after 15 years. Breast cancer survivors with Charlson Comorbidity Index score ≥2 had a significantly higher risk of diseases of the circulatory system (HR, 2.64; 95% CI, 1.08-6.45) beyond 10 years following breast cancer diagnosis. Similarly, older age, obesity, lower education, and family history of CVD and breast cancer were risk factors for heart and circulatory system diseases among long-term breast cancer survivors. CONCLUSION: Risk of CVD compared to the general population was moderate among this cohort of long-term breast cancer survivors between 10 to 15 years since cancer diagnosis. Awareness of CVD risks is important for breast cancer survivors.

Mental health disorders are more common in patients with Hodgkin lymphoma and may negatively impact overall survival.

BACKGROUND: Long-term mental health outcomes were characterized in patients who were diagnosed with Hodgkin lymphoma (HL), and risk factors for the development of mental health disorders were identified. METHODS: Patients who were diagnosed with HL between 1997 and 2014 were identified in the Utah Cancer Registry. Each patient was matched with up to five individuals from a general population cohort identified within the Utah Population Database, a unique source of linked records that includes patient and demographic data. RESULTS: In total, 795 patients who had HL were matched with 3575 individuals from the general population. Compared with the general population, patients who had HL had a higher risk of any mental health diagnosis (hazard ratio, 1.77; 95% confidence interval, 1.57-2.00). Patients with HL had higher risks of anxiety, depression, substance-related disorders, and suicide and intentional self-inflicted injuries compared with the general population. The main risk factor associated with an increased risk of being diagnosed with mental health disorders was undergoing hematopoietic stem cell transplantation, with a hazard ratio of 2.06 (95% confidence interval, 1.53-2.76). The diagnosis of any mental health disorder among patients with HL was associated with a detrimental impact on overall survival; the 10-year overall survival rate was 70% in patients who had a mental health diagnosis compared with 86% in those patients without a mental health diagnosis (p < .0001). CONCLUSIONS: Patients who had HL had an increased risk of various mental health disorders compared with a matched general population. The current data illustrate the importance of attention to mental health in HL survivorship, particularly for patients who undergo therapy with hematopoietic stem cell transplantation.

Sexual dysfunction among gynecologic cancer survivors in a population-based cohort study.

Treatment for gynecologic cancer is associated with sexual dysfunction, which may present during and/or after treatment. The aim of this study was to investigate the risk of sexual dysfunction among gynecologic cancer survivors compared to cancer-free women in a population-based cohort study. We identified a cohort of 4863 endometrial, ovarian, and cervical cancer survivors diagnosed between 1997 and 2012 in the Utah Cancer Registry. Up to five cancer-free women were matched to cancer survivors (N = 22,693). We used ICD-9 codes to identify sexual dysfunction. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for sexual dysfunction with adjustment for potential confounders. Approximately 6.6% of gynecologic cancer survivors had sexual dysfunction diagnoses 1-5 years after cancer diagnosis. Gynecologic cancer survivors had higher risks of overall sexual dysfunction (HR: 2.51, 95% CI: 2.16, 2.93), dyspareunia (HR: 3.27, 95% CI: 2.63, 4.06), and vaginal dryness (HR: 2.63, 95% CI: 2.21, 3.12) compared to a general population of women, 1-5 years after cancer diagnosis. Sexual dysfunction was associated with advance cancer stage (HRRegional vs. Localized: 1.61, 95% CI: 1.19, 2.31), radiation therapy (HR: 1.73, 95% CI: 1.29, 2.31), and chemotherapy (HR: 1.80, 95% CI: 1.30, 2.50). This large cohort study confirms that there is an increased risk of sexual dysfunction among gynecologic cancer survivors when compared to the general population. Further investigation is needed to address the risk factors for sexual dysfunction and to improve patient-provider communication, diagnosis, documentation, and treatment of sexual dysfunction among gynecologic cancer survivors.

Copulation in antiarch placoderms and the origin of gnathostome internal fertilization.

Reproduction in jawed vertebrates (gnathostomes) involves either external or internal fertilization. It is commonly argued that internal fertilization can evolve from external, but not the reverse. Male copulatory claspers are present in certain placoderms, fossil jawed vertebrates retrieved as a paraphyletic segment of the gnathostome stem group in recent studies. This suggests that internal fertilization could be primitive for gnathostomes, but such a conclusion depends on demonstrating that copulation was not just a specialized feature of certain placoderm subgroups. The reproductive biology of antiarchs, consistently identified as the least crownward placoderms and thus of great interest in this context, has until now remained unknown. Here we show that certain antiarchs possessed dermal claspers in the males, while females bore paired dermal plates inferred to have facilitated copulation. These structures are not associated with pelvic fins. The clasper morphology resembles that of ptyctodonts, a more crownward placoderm group, suggesting that all placoderm claspers are homologous and that internal fertilization characterized all placoderms. This implies that external fertilization and spawning, which characterize most extant aquatic gnathostomes, must be derived from internal fertilization, even though this transformation has been thought implausible. Alternatively, the substantial morphological evidence for placoderm paraphyly must be rejected.

Identifying patients who access musculoskeletal physical therapy: a retrospective cohort analysis.

BACKGROUND: Musculoskeletal conditions are common and cause high levels of disability and costs. Physical therapy is recommended for many musculoskeletal conditions. Past research suggests that referral rates appear to have increased over time, but the rate of accessing a physical therapist appears unchanged. OBJECTIVE: Our retrospective cohort study describes the rate of physical therapy use after referral for a variety of musculoskeletal diagnoses while comparing users and non-users of physical therapy services after referral. METHODS: The study sample included patients in the University of Utah Health system who received care from a medical provider for a musculoskeletal condition. We included a comprehensive set of variables available in the electronic data warehouse possibly associated with attending physical therapy. Our primary analysis compared differences in patient factors between physical therapy users and non-users using Poisson regression. RESULTS: 15 877 (16%) patients had a referral to physical therapy, and 3812 (24%) of these patients accessed physical therapy after referral. Most of the factors included in the model were associated with physical therapy use except for sex and number of comorbidities. The receiver operating characteristic curve was 0.63 suggesting poor predictability of the model but it is likely related to the heterogeneity of the sample. CONCLUSIONS: We found that obesity, ethnicity, public insurance and urgent care referrals were associated with poor adherence to physical therapy referral. However, the limited predictive power of our model suggests a need for a deeper examination into factors that influence patients access to a physical therapist.

Adverse respiratory outcomes among head and neck cancer survivors in the Utah Cancer Survivors Study.

BACKGROUND: The number of head and neck cancer (HNC) survivors has been increasing because of improving survival in the United States. The aim of this study was to evaluate the incidence of respiratory disease diagnoses in HNC survivors in comparison with cancer-free individuals. A second aim was to investigate risk factors for respiratory disease among HNC survivors. METHODS: Patients with HNC diagnosed from 1996 to 2012 were identified in the Utah Cancer Registry (n = 1901). Up to 5 cancer-free individuals from the general population (n = 7796) were matched to each HNC survivor by birth year, sex, birth state, and follow-up time. Electronic medical records and statewide health care facility data were used to identify a disease diagnosis after the cancer diagnosis. Cox proportional hazards models were used to estimate the risks of respiratory diseases. RESULTS: The median follow-up times were 4.5 years for HNC survivors and 7.8 years for the general population cohort. The risks of respiratory infection (hazard ratio [HR], 1.63; 95% confidence interval [CI], 1.40-1.90), chronic obstructive pulmonary diseases and bronchiectasis (HR, 2.65; 95% CI, 2.13-3.29), and aspiration pneumonitis (HR, 6.21; 95% CI, 3.98-9.68) were higher among HNC survivors than the general population cohort more than 5 years after the cancer diagnosis. Age at diagnosis, baseline body mass index, sex, baseline smoking status, treatment modality, primary site, and stage were associated with the risk of adverse respiratory outcomes among HNC survivors. CONCLUSIONS: The risk of adverse respiratory outcomes was much higher among HNC survivors than the general population cohort. Multidisciplinary care is needed to prevent the occurrence of adverse respiratory outcomes among HNC survivors.

Rural-urban disparities in colorectal cancer survival and risk among men in Utah: a statewide population-based study.

Rural areas of the U.S. experience disproportionate colorectal cancer (CRC) death compared to urban areas. The authors aimed to analyze differences in CRC survival between rural and urban Utah men and investigate potential prognostic factors for survival among these men. A cohort of Utah men diagnosed with CRC between 1997 and 2013 was identified from the Utah Cancer Registry. Survival and prognostic factors were analyzed via 5-year CRC survival and Cox proportional hazards models, stratified by rural/urban residence. Among 4,660 men diagnosed with CRC, 15.3% were living in rural Utah. Compared with urban men, rural CRC patients were diagnosed at older ages and in different anatomic subsites; more were overweight, and current smokers. Differences in stage and treatment were not apparent between rural and urban CRC patients. Compared with urban counterparts, rural men experienced a lower CRC survival (Hazard Ratio 0.55, 95% CI 0.53, 0.58 vs. 0.58, 95% CI 0.56, 0.59). Race and cancer treatment influenced CRC survival among men living in both urban and rural areas. Factors of CRC survival varied greatly among urban and rural men in Utah. The influence of social and environmental conditions on health behaviors and outcomes merits further exploration.

First evidence of a functional spiracle in stem chondrichthyan acanthodians, with the oldest known elastic cartilage.

Spiracles are a general character of gnathostomes (jawed fishes), being present in antiarch placoderms, commonly regarded as the most basal gnathostome group. The presence of spiracular tubes in acanthodians has been deduced from grooves on the neurocranium of the derived acanthodiform Acanthodes bronni from the Permian of Germany, but until now these tubes were presumed to lack an external opening, rendering them non-functional. Here we describe the external spiracular elements in specimens of the Middle Devonian acanthodiforms Cheiracanthus murchisoni, Cheiracanthus latus and Mesacanthus pusillus from northern Scotland, and the internal structure of these elements in C. murchisoni, demonstrating that the spiracle in acanthodiforms differed from all known extant and extinct fishes in having paired cartilage-pseudobranch structures. This arrangement represents a transitional state between the presumed basal gnathostome condition with an unconstricted first gill slit (as yet not identified in any fossil) and the derived condition with a spiracle and a single pseudobranch derived from the posterior hemibranch of the mandibular arch. We identify the main tissue forming the pseudobranch as elastic cartilage, a tissue previously unrecorded in fossils.

Genitourinary disease risks among ovarian cancer survivors in a population-based cohort study.

OBJECTIVE: While genitourinary complications during treatment for ovarian cancer are well-known, long-term adverse outcomes have not been well characterized. The number of ovarian cancer survivors has been increasing. The aim of this study was to investigate long-term adverse genitourinary outcomes in a population-based cohort. METHODS: We identified a cohort of 1270 ovarian cancer survivors diagnosed between 1996 and 2012 from the Utah Cancer Registry, and 5286 cancer-free women were matched on birth year and state from the Utah Population Database. Genitourinary disease diagnoses were identified through ICD-9 codes from electronic medical records and statewide healthcare facilities data. Cox proportional hazards models were used to estimate hazard ratios (HR) for genitourinary outcomes at 1 to <5 years and 5+ years after ovarian cancer diagnosis. RESULTS: Ovarian cancer survivors had increased risks for urinary system disorders (HR: 2.53, 95% CI: 2.12-3.01) and genital organ disorders (HR: 1.88, 95% CI: 1.57-2.27) between 1 and <5 years after cancer diagnosis compared to the general population cohort. Increased risks were observed for acute renal failure, chronic kidney disease, calculus of kidney, hydronephrosis, pelvic peritoneal adhesions, and pelvic organ inflammatory conditions. Increased risks of several of these diseases were observed 5+ years after cancer diagnosis. CONCLUSIONS: Ovarian cancer survivors experience increased risks of various genitourinary diseases compared to women in the general population in the long-term. Understanding the multimorbidity trajectory among ovarian cancer survivors is important to improve clinical care after cancer treatment is completed.

Long-term diabetes risk among endometrial cancer survivors in a population-based cohort study.

OBJECTIVE: The majority of endometrial cancer patients are overweight or obese at cancer diagnosis. Obesity is a shared risk factor for both endometrial cancer and diabetes, but it is unknown whether endometrial cancer patients have increased diabetes risks. The aim of our study was to investigate diabetes risk among endometrial cancer patients. METHODS: Endometrial cancer patients diagnosed between 1997 and 2012 in Utah (n = 2,314) were identified. Women from the general population (n = 8,583) were matched to the cancer patients on birth year and birth state. Diabetes diagnoses were identified from electronic medical records and statewide healthcare facility databases. Cox proportional hazards models were used to estimate hazard ratios for diabetes after cancer diagnosis. RESULTS: Endometrial cancer survivors had a significantly higher risk of type II diabetes when compared to women from the general population in the first year after cancer diagnosis (HR = 5.22, 95% CI = 4.05, 6.71), >1-5 years after cancer diagnosis (HR = 1.67, 95% CI = 1.31, 2.12), and >5 years after cancer diagnosis (HR = 1.65, 95% CI = 1.29, 2.11). Endometrial cancer patients who were obese at cancer diagnosis had a three-fold increase in type II diabetes risk (HR = 2.99, 95%CI = 2.59, 3.45). Although endometrial cancer patients diagnosed at distant stage had a higher risk of diabetes, cancer treatment did not appear to contribute to any diabetes risks. CONCLUSIONS: In conclusion, endometrial cancer survivors had a higher risk of diabetes than women in the general population. These results suggest that long term monitoring for diabetes is indicated for endometrial cancer survivors.

Emergency department visits for electric scooter-related injuries after introduction of an urban rental program.

BACKGROUND: Providers in Salt Lake City emergency departments (EDs) anecdotally noted a significant number of electronic scooter (e-scooter)-related injuries since the launch of e-scooter rentals in the downtown area in June 2018. The aim of this study was to quantify and characterize these injuries. METHODS: We reviewed the electronic medical records of the University of Utah ED and the Salt Lake Regional Medical Center ED. Using a broad keyword search for "scooter," we examined all notes for ED visits between June 15-November 15, 2017, and June 15-November 15, 2018, and identified e-scooter related injuries. The 2017 data pre-dated the launch of the e-scooter share programs in Salt Lake City and served as a control period. RESULTS: We noted 8 scooter-related injuries in 2017 and 50 in 2018. Injury types from the 2018 period included: major head injury (8%); major musculoskeletal injury (36%); minor head injury (12%); minor musculoskeletal injury (34%); and superficial soft tissue injury (40%). 24% of patients presented via ambulance and 6% presented as a trauma activation. 16% of patients required hospital admission and 14% had an injury requiring operative repair. 16% reported alcohol intoxication and none of the patients reported wearing a helmet at the time of the injury. CONCLUSION: Since the launch of e-scooter share programs in Salt Lake City, we have seen a substantial increase in e-scooter related trauma in our EDs. Of particular note is the number of patients with major head injuries and major musculoskeletal injuries.

Prognostic factors for rural endometrial cancer patients in a population-based cohort.

BACKGROUND: Endometrial cancer is the second most common cancer among female cancer survivors in the US and is increasing in incidence. Rural endometrial cancer patients experience lower survival rates but the reasons for the lower survival are not known. The aim of this study is to examine whether prognostic factors are different for rural and urban patients in a population-based cohort. METHODS: Endometrial cancer patients diagnosed 1997-2012 were identified through the Utah Cancer Registry and Utah Population Database. The address at cancer diagnosis was used to classify patients in rural or urban residences. Demographic and cancer-specific characteristics were examined as prognostic factors for both all-cause and endometrial cancer-specific mortality using Cox proportional hazards models. RESULTS: There were 2,994 endometrial cancer patients and 14.1% of these patients lived in rural areas at diagnosis. Rural endometrial cancer patients were older at cancer diagnosis and did not appear to be different in terms of obesity or overweight at cancer diagnosis. There were no differences for treatment or stage at diagnosis although rural patients had higher proportions of higher grade. Age at diagnosis, poverty, education, and histology were significant prognostic factors for all-cause death. Rural patients with more advanced stages of cancer had significantly increased risks of all-cause and endometrial cancer-specific death than urban patients. Rural endometrial cancer patients diagnosed at advanced stage had a 17-fold increase in the risk of all-cause death compared to an 8-fold increase in death for urban patients. CONCLUSIONS: Rural endometrial cancer patients in Utah were older at diagnosis, had higher grade and higher comorbidities. While urban and rural endometrial cancer patients shared many prognostic factors, the risk of mortality is greater among rural patients with advanced stage endometrial cancer. Future studies should examine where patients are receiving treatment and how that impacts their survival and how to reduce the mortality rates of high risk patients.

Stabilizer Slicing: Coherent Error Cancellations in Low-Density Parity-Check Stabilizer Codes.

Coherent errors are a dominant noise process in many quantum computing architectures. Unlike stochastic errors, these errors can combine constructively and grow into highly detrimental overrotations. To combat this, we introduce a simple technique for suppressing systematic coherent errors in low-density parity-check stabilizer codes, which we call stabilizer slicing. The essential idea is to slice low-weight stabilizers into two equally weighted Pauli operators and then apply them by rotating in opposite directions, causing their overrotations to interfere destructively on the logical subspace. With access to native gates generated by three-body Hamiltonians, we can completely eliminate purely coherent overrotation errors, and for overrotation noise of 0.99 unitarity we achieve a 135-fold improvement in the logical error rate of surface-17. For more conventional two-body ion trap gates, we observe an 89-fold improvement for Bacon-Shor-13 with purely coherent errors which should be testable in near-term fault-tolerance experiments. This second scheme takes advantage of the prepared gauge degrees of freedom, and to our knowledge is the first example in which the state of the gauge directly affects the robustness of a code's memory. This Letter demonstrates that coherent noise is preferable to stochastic noise within certain code and gate implementations when the coherence is utilized effectively.

Photo-stability study of a solution-processed small molecule solar cell system: correlation between molecular conformation and degradation.

Solution-processed organic small molecule solar cells (SMSCs) have achieved efficiency over 11%. However, very few studies have focused on their stability under illumination and the origin of the degradation during the so-called burn-in period. Here, we studied the burn-in period of a solution-processed SMSC using benzodithiophene terthiophene rhodamine:[6,6]-phenyl C71 butyric acid methyl ester (BTR:PC71BM) with increasing solvent vapour annealing time applied to the active layer, controlling the crystallisation of the BTR phase. We find that the burn-in behaviour is strongly correlated to the crystallinity of BTR. To look at the possible degradation mechanisms, we studied the fresh and photo-aged blend films with grazing incidence X-ray diffraction, UV-vis absorbance, Raman spectroscopy and photoluminescence (PL) spectroscopy. Although the crystallinity of BTR affects the performance drop during the burn-in period, the degradation is found not to originate from the crystallinity changes of the BTR phase, but correlates with changes in molecular conformation - rotation of the thiophene side chains, as resolved by Raman spectroscopy which could be correlated to slight photobleaching and changes in PL spectra.

Bayesian Networks Improve Causal Environmental Assessments for Evidence-Based Policy.

Rule-based weight of evidence approaches to ecological risk assessment may not account for uncertainties and generally lack probabilistic integration of lines of evidence. Bayesian networks allow causal inferences to be made from evidence by including causal knowledge about the problem, using this knowledge with probabilistic calculus to combine multiple lines of evidence, and minimizing biases in predicting or diagnosing causal relationships. Too often, sources of uncertainty in conventional weight of evidence approaches are ignored that can be accounted for with Bayesian networks. Specifying and propagating uncertainties improve the ability of models to incorporate strength of the evidence in the risk management phase of an assessment. Probabilistic inference from a Bayesian network allows evaluation of changes in uncertainty for variables from the evidence. The network structure and probabilistic framework of a Bayesian approach provide advantages over qualitative approaches in weight of evidence for capturing the impacts of multiple sources of quantifiable uncertainty on predictions of ecological risk. Bayesian networks can facilitate the development of evidence-based policy under conditions of uncertainty by incorporating analytical inaccuracies or the implications of imperfect information, structuring and communicating causal issues through qualitative directed graph formulations, and quantitatively comparing the causal power of multiple stressors on valued ecological resources. These aspects are demonstrated through hypothetical problem scenarios that explore some major benefits of using Bayesian networks for reasoning and making inferences in evidence-based policy.