Intelligent Knowledge Distribution: Constrained-Action POMDPs for Resource-Aware Multiagent Communication.

This article addresses a fundamental question of multiagent knowledge distribution: what information should be sent to whom and when with the limited resources available to each agent? Communication requirements for multiagent systems can be rather high when an accurate picture of the environment and the state of other agents must be maintained. To reduce the impact of multiagent coordination on networked systems, for example, power and bandwidth, this article introduces two concepts for the partially observable Markov decision processes (POMDPs): 1) action-based constraints that yield constrained-action POMDPs (CA-POMDPs) and 2) soft probabilistic constraint satisfaction for the resulting infinite-horizon controllers. To enable constraint analysis over an infinite horizon, an unconstrained policy is first represented as a finite-state controller (FSC) and optimized with policy iteration. The FSC representation then allows for a combination of the Markov chain Monte Carlo and discrete optimization to improve the probabilistic constraint satisfaction of the controller while minimizing the impact on the value function. Within the CA-POMDP framework, we then propose intelligent knowledge distribution (IKD) which yields per-agent policies for distributing knowledge between agents subject to interaction constraints. Finally, the CA-POMDP and IKD concepts are validated using an asset tracking problem where multiple unmanned aerial vehicles (UAVs) with heterogeneous sensors collaborate to localize a ground asset to assist in avoiding unseen obstacles in a disaster area. The IKD model was able to maintain asset tracking through multiagent communications while only violating soft power and bandwidth constraints 3% of the time, while greedy and naive approaches violated constraints more than 60% of the time.

Patient reported outcome measures in a cohort of patients at high risk of breast cancer treated by bilateral risk reducing mastectomy and breast reconstruction.

BACKGROUND: Many women with increased lifetime risk of developing breast cancer, due to pathogenic gene variants or family history, choose to undergo bilateral risk reducing mastectomies (BRRM). Patient reported outcome measures (PROMS) are an increasingly important part of informed consent but are little studied in women undergoing BRRM. METHODS: We used a validated PROMS tool for breast reconstruction (BREAST-Q) in 297 women who had BRRM and breast reconstruction, 81% of whom had no malignancy (Benign Group, BG) and 19% in whom a perioperative breast cancer was diagnosed (Cancer Group, CG). 128 women also completed a Hospital Anxiety & Depression Score (HADS) questionnaire to test if preoperative HADS score could predict PROMS outcomes. RESULTS: Women in the CG had lower PROMS scores for satisfaction with their breasts, nipple reconstruction and sexual wellbeing. Both groups reported equal satisfaction with BRRM outcome and psychosocial well-being. Physical well-being PROMS of the abdomen and chest were high in women in both groups as were scores for satisfaction with the care they received. The CG group reported suboptimal quality of patient information. A higher presurgical HADS anxiety score predicted less favourable postoperative psychosocial well-being despite similar levels of satisfaction with aesthetic outcome. CONCLUSION: We show a high degree of patient reported satisfaction by woman undergoing BRRM and reconstruction. There was a negative association with a cancer diagnosis on quality of life PROMS and higher preoperative anxiety levels negatively affected postoperative psychosocial well-being. These important findings should be part of the informed consent process during preoperative counselling.

Borderline resectable pancreatic cancer: conceptual evolution and current approach to image-based classification.

BACKGROUND: Diagnostic imaging plays a critical role in the initial diagnosis and therapeutic monitoring of pancreatic adenocarcinoma. Over the past decade, the concept of 'borderline resectable' pancreatic cancer has emerged to describe a distinct subset of patients existing along the spectrum from resectable to locally advanced disease for whom a microscopically margin-positive (R1) resection is considered relatively more likely, primarily due to the relationship of the primary tumor with surrounding vasculature. MATERIALS AND METHODS: This review traces the conceptual evolution of borderline resectability from a radiological perspective, including the debates over the key imaging criteria that define the thresholds between resectable, borderline resectable, and locally advanced or metastatic disease. This review also addresses the data supporting neoadjuvant therapy in this population and discusses current imaging practices before and during treatment. RESULTS: A growing body of evidence suggests that the borderline resectable group of patients may particularly benefit from neoadjuvant therapy to increase the likelihood of an ultimately margin-negative (R0) resection. Unfortunately, anatomic and imaging criteria to define borderline resectability are not yet universally agreed upon, with several classification systems proposed in the literature and considerable variance in institution-by-institution practice. As a result of this lack of consensus, as well as overall small patient numbers and lack of established clinical trials dedicated to borderline resectable patients, accurate evidence-based diagnostic categorization and treatment selection for this subset of patients remains a significant challenge. CONCLUSIONS: Clinicians and radiologists alike should be cognizant of evolving imaging criteria for borderline resectability given their profound implications for treatment strategy, follow-up recommendations, and prognosis.

Improving the uptake of predictive testing and colorectal screening in Lynch syndrome: a regional primary care survey.

Lynch syndrome (LS) is an autosomal dominant cancer predisposition syndrome with a 60-80% lifetime risk of colorectal cancer. We assessed the uptake of predictive testing and colorectal screening among first-degree relatives (FDRs) in LS families and explored novel methods for informing and engaging at-risk relatives. Uptake of predictive testing was explored using Kaplan-Meier analysis and engagement with colorectal screening was ascertained. A questionnaire was distributed to 216 general practitioners (GPs) of registered LS family members to determine their prior experience and opinion of an enhanced role. Of 591, 329 (55.7%) FDRs had undergone predictive testing. Uptake was significantly lower in males (p = 0.012) and individuals <25 years (p < 0.001). Mutation carriers were more likely to undergo colorectal screening than untested FDRs (97.2% vs 34.9%; P ≤ 0.0001). Of 216, 63 (29.2%) questionnaires were returned. Most GPs (55/63; 87.3%) were not confident to discuss the details of LS with patients and relatives. The main barriers were lack of knowledge and concerns about confidentiality. Compliance with colorectal screening is excellent following a mutation positive predictive test. Uptake of predictive testing could be substantially improved, particularly among males and younger age groups. GPs are unlikely to actively participate in communication with at-risk relatives without considerable support.

A magnetic particle time-of-flight (MagPTOF) diagnostic for measurements of shock- and compression-bang time at the NIF (invited).

A magnetic particle time-of-flight (MagPTOF) diagnostic has been designed to measure shock- and compression-bang time using D(3)He-fusion protons and DD-fusion neutrons, respectively, at the National Ignition Facility (NIF). This capability, in combination with shock-burn weighted areal density measurements, will significantly constrain the modeling of the implosion dynamics. This design is an upgrade to the existing particle time-of-flight (pTOF) diagnostic, which records bang times using DD or DT neutrons with an accuracy better than ±70 ps [H. G. Rinderknecht et al., Rev. Sci. Instrum. 83, 10D902 (2012)]. The inclusion of a deflecting magnet will increase D(3)He-proton signal-to-background by a factor of 1000, allowing for the first time simultaneous measurements of shock- and compression-bang times in D(3)He-filled surrogate implosions at the NIF.

Conceptual design of the gamma-to-electron magnetic spectrometer for the National Ignition Facility.

The Gamma-to-Electron Magnetic Spectrometer (GEMS) diagnostic is designed to measure the prompt γ-ray energy spectrum during high yield deuterium-tritium (DT) implosions at the National Ignition Facility (NIF). The prompt γ-ray spectrum will provide "burn-averaged" observables, including total DT fusion yield, total areal density (ρR), ablator ρR, and fuel ρR. These burn-averaged observables are unique because they are essentially averaged over 4π, providing a global reference for the line-of-sight-specific measurements typical of x-ray and neutron diagnostics. The GEMS conceptual design meets the physics-based requirements: ΔE/E = 3%-5% can be achieved in the range of 2-25 MeV γ-ray energy. Minimum DT neutron yields required for 15% measurement uncertainty at low-resolution mode are: 5 × 10(14) DT-n for ablator ρR (at 0.2 g/cm(2)); 2 × 10(15) DT-n for total DT yield (at 4.2 × 10(-5) γ/n); and 1 × 10(16) DT-n for fuel ρR (at 1 g/cm(2)).

Hohlraum glint and laser pre-pulse detector for NIF experiments using velocity interferometer system for any reflector.

Laser pre-pulse and early-time laser reflection from the hohlraum wall onto the capsule (termed "glint") can cause capsule imprint and unwanted early-time shocks on indirect drive implosion experiments. In a minor modification to the existing velocity interferometer system for any reflector diagnostic on NIF a fast-response vacuum photodiode was added to detect this light. The measurements show evidence of laser pre-pulse and possible light reflection off the hohlraum wall and onto the capsule.

An evaluation of hernia education in surgical residency programs.

PURPOSE: The purpose of this study was to evaluate surgical residents' educational experience related to ventral hernias. METHODS: A 16-question survey was sent to all program coordinators to distribute to their residents. Consent was obtained following a short introduction of the purpose of the survey. Comparisons based on training level were made using χ(2) test of independence, Fisher's exact, and Fisher's exact with Monte Carlo estimate as appropriate. A p value <0.05 was considered significant. RESULTS: The survey was returned by 183 residents from 250 surgical programs. Resident postgraduate year (PG-Y) level was equivalent among groups. Preferred techniques for open ventral hernia varied; the most common (32 %) was intra-abdominal placement of mesh with defect closure. Twenty-two percent of residents had not heard of the retrorectus technique for hernia repair, 48 % had not performed the operation, and 60 % were somewhat comfortable with and knew the general categories of mesh prosthetics products. Mesh choices, biologic and synthetic, varied among the different products. The most common type of hernia education was teaching in the operating room in 87 %, didactic lecture 69 %, and discussion at journal club 45 %. Number of procedures, comfort level with open and laparoscopic techniques, indications for mesh use and technique, familiarity and use of retrorectus repair, and type of hernia education varied significantly based on resident level (p < 0.05). CONCLUSION: Exposure to hernia techniques and mesh prosthetics in surgical residency programs appears to vary. Further evaluation is needed and may help in standardizing curriculums for hernia repair for surgical residents.

Tailoring genetic/genomic services and information to the individual.

This article examines how to develop confidence and competence in tailoring genetic/genomic information for different patients. The focus is on the issues that nurses working in a multicultural society need to be aware of, and include taking into account people's ethnicity, culture, religion and ethical perspectives, as well as their developmental stage.

Neutron spectrometry--an essential tool for diagnosing implosions at the National Ignition Facility (invited).

DT neutron yield (Y(n)), ion temperature (T(i)), and down-scatter ratio (dsr) determined from measured neutron spectra are essential metrics for diagnosing the performance of inertial confinement fusion (ICF) implosions at the National Ignition Facility (NIF). A suite of neutron-time-of-flight (nTOF) spectrometers and a magnetic recoil spectrometer (MRS) have been implemented in different locations around the NIF target chamber, providing good implosion coverage and the complementarity required for reliable measurements of Y(n), T(i), and dsr. From the measured dsr value, an areal density (ρR) is determined through the relationship ρR(tot) (g∕cm(2)) = (20.4 ± 0.6) × dsr(10-12 MeV). The proportionality constant is determined considering implosion geometry, neutron attenuation, and energy range used for the dsr measurement. To ensure high accuracy in the measurements, a series of commissioning experiments using exploding pushers have been used for in situ calibration of the as-built spectrometers, which are now performing to the required accuracy. Recent data obtained with the MRS and nTOFs indicate that the implosion performance of cryogenically layered DT implosions, characterized by the experimental ignition threshold factor (ITFx), which is a function of dsr (or fuel ρR) and Y(n), has improved almost two orders of magnitude since the first shot in September, 2010.

Testing a new NIF neutron time-of-flight detector with a bibenzyl scintillator on OMEGA.

A new neutron time-of-flight (nTOF) detector with a bibenzyl crystal as a scintillator has been designed and manufactured for the National Ignition Facility (NIF). This detector will replace a nTOF20-Spec detector with an oxygenated xylene scintillator currently operational on the NIF to improve the areal-density measurements. In addition to areal density, the bibenzyl detector will measure the D-D and D-T neutron yield and the ion temperature of indirect- and direct-drive-implosion experiments. The design of the bibenzyl detector and results of tests on the OMEGA Laser System are presented.

Deuterium-tritium neutron yield measurements with the 4.5 m neutron-time-of-flight detectors at NIF.

The first several campaigns of laser fusion experiments at the National Ignition Facility (NIF) included a family of high-sensitivity scintillator∕photodetector neutron-time-of-flight (nTOF) detectors for measuring deuterium-deuterium (DD) and DT neutron yields. The detectors provided consistent neutron yield (Y(n)) measurements from below 10(9) (DD) to nearly 10(15) (DT). The detectors initially demonstrated detector-to-detector Y(n) precisions better than 5%, but lacked in situ absolute calibrations. Recent experiments at NIF now have provided in situ DT yield calibration data that establish the absolute sensitivity of the 4.5 m differential tissue harmonic imaging (DTHI) detector with an accuracy of ± 10% and precision of ± 1%. The 4.5 m nTOF calibration measurements also have helped to establish improved detector impulse response functions and data analysis methods, which have contributed to improving the accuracy of the Y(n) measurements. These advances have also helped to extend the usefulness of nTOF measurements of ion temperature and downscattered neutron ratio (neutron yield 10-12 MeV divided by yield 13-15 MeV) with other nTOF detectors.

A novel particle time of flight diagnostic for measurements of shock- and compression-bang times in D3He and DT implosions at the NIF.

The particle-time-of-flight (pTOF) diagnostic, fielded alongside a wedge range-filter (WRF) proton spectrometer, will provide an absolute timing for the shock-burn weighted ρR measurements that will validate the modeling of implosion dynamics at the National Ignition Facility (NIF). In the first phase of the project, pTOF has recorded accurate bang times in cryogenic DT, DT exploding pusher, and D(3)He implosions using DD or DT neutrons with an accuracy better than ±70 ps. In the second phase of the project, a deflecting magnet will be incorporated into the pTOF design for simultaneous measurements of shock- and compression-bang times in D(3)He-filled surrogate implosions using D(3)He protons and DD-neutrons, respectively.

Genotype-phenotype correlation in colorectal polyposis.

Familial adenomatous polyposis (FAP) has been divided into three clinical subtypes: mild, classical and severe. This study aimed to investigate for a correlation between genotype and phenotype. A codon-specific survival difference is unknown. A retrospective longitudinal study of 492 patients on the Manchester Polyposis Registry was conducted. Patients were grouped according to genotypes: 0, unknown mutation; 1, adenomatous polyposis coli (APC) 0-178 (and 312-412 of exon 9); 2, APC >1550; 3, APC 179-1249; 4, APC 1250-1549; and 5, MutYH. Date of onset of polyposis, incidence of colorectal cancer (CRC), survival and actuarial time to surgery were calculated. Median age of onset of polyposis for genotype 0 was 20.3 years, genotype 1 35.6 years, genotype 2 32.2, genotype 3 15.9 years, and genotype 4 14.8 years (p < 0.0001). Age of onset of CRC was similar between genotypes. Median survival for genotype 0 was 56.6 years, genotype 1 74.9 years, genotype 2 61.0 years, genotype 3 63.0 years, genotype 4 48.1 years, and genotype 5 69.7 years (p = 0.003). This survival difference was also seen when patients who underwent screening and those who did not were analysed separately. Survival in the screened population was 53.9 years in genotype 4 and 72.9 years in genotype 3. Patients with genotype 4 (APC 1249-1549) have a significantly worse survival despite screening and early prophylactic surgery. This analysis supports a genotype-phenotype correlation. Patients with a mutation APC 1249-1549 develop polyposis at an early age and have a worse survival. Patients with a mutation APC 0-178 or 312-412 develop polyposis later and have an improved survival. This survival difference has not previously been documented.

Uptake of risk-reducing salpingo-oophorectomy in women carrying a BRCA1 or BRCA2 mutation: evidence for lower uptake in women affected by breast cancer and older women.

BACKGROUND: Bilateral risk-reducing salpingo-oophorectomy (BRRSO) is the only effective way of reducing mortality from ovarian cancer. This study investigates uptake of BRRSO in 700 BRCA1/2 mutation carriers from Greater Manchester. METHODS: Dates of last follow-up and BRRSO were obtained, and the following variables were investigated: ovarian cancer risk/gene, age and breast cancer history. The date of the genetic mutation report was the initiation for Kaplan-Meier analysis. RESULTS: The uptake of BRRSO in BRCA1 mutation carriers was 54.5% (standard error 3.6%) at 5 years post testing compared with 45.5% (standard error 3.2%) in BRCA2 mutation carriers (P=0.045). The 40-59 years category showed the greatest uptake for BRRSO and uptake was significantly lower in the over 60 s (P<0.0001). Of the unaffected BRCA1 mutation carriers, 65% (standard error 5.1%) opted for surgery at 5 years post-testing compared with 41.1% (standard error 5.1%) in affected BRCA1 mutation carriers (P=0.045). CONCLUSION: The uptake of BRRSO is lower in women previously affected by breast cancer and in older women. As there is no efficient method for early detection of ovarian cancer, uptake should ideally be greater. Counselling should be offered to ensure BRCA1/2 mutation carriers make an informed decision about managing their ovarian cancer risk.

Hernia recurrence through a composite mesh secondary to transfascial suture holes.

Laparoscopic ventral hernia repair is an accepted method for incisional hernia repair. Although techniques vary, transfascial suturing of the mesh to the abdominal wall has been proposed as a viable way to fixate the mesh and reduce recurrence rates. We report a 54-year-old woman who had previously undergone a laparoscopic ventral hernia repair following a laparoscopic tubal ligation using a Composix mesh. The patient presented with a symptomatic hernia recurrence. The computed tomography scan showed a periumbilical hernia containing fat. The patient underwent diagnostic laparoscopy and lysis of adhesions. During the lysis of adhesions, a recurrence through the previously placed composite mesh was encountered where holes had been made by the previously placed transfascial sutures. The hernia was reduced, mesh was removed, and an ePTFE mesh was used to repair the hernia. The mechanism of recurrence appeared to be improperly placed transfascial sutures; overly large bites of mesh caused excessive tension and ultimately a hole in the mesh. Hernia recurrence due to mesh or transfascial suture failure is rarely reported and most often caused by inadequate fixation. Our case highlights the need for meticulous placement of transfascial sutures and demonstrates a mechanism of recurrence due to inadequate placement.

CLC and IFNAR1 are differentially expressed and a global immunity score is distinct between early- and late-onset colorectal cancer.

Colorectal cancer (CRC) incidence increases with age, and early onset of the disease is an indication of genetic predisposition, estimated to cause up to 30% of all cases. To identify genes associated with early-onset CRC, we investigated gene expression levels within a series of young patients with CRCs who are not known to carry any hereditary syndromes (n=24; mean 43 years at diagnosis), and compared this with a series of CRCs from patients diagnosed at an older age (n=17; mean 79 years). Two individual genes were found to be differentially expressed between the two groups, with statistical significance; CLC was higher and IFNAR1 was less expressed in early-onset CRCs. Furthermore, genes located at chromosome band 19q13 were found to be enriched significantly among the genes with higher expression in the early-onset samples, including CLC. An elevated immune content within the early-onset group was observed from the differentially expressed genes. By application of outlier statistics, H3F3A was identified as a top candidate gene for a subset of the early-onset CRCs. In conclusion, CLC and IFNAR1 were identified to be overall differentially expressed between early- and late-onset CRC, and are important in the development of early-onset CRC.

National Ignition Facility neutron time-of-flight measurements (invited).

The first 3 of 18 neutron time-of-flight (nTOF) channels have been installed at the National Ignition Facility (NIF). The role of these detectors includes yield, temperature, and bang time measurements. This article focuses on nTOF data analysis and quality of results obtained for the first set of experiments to use all 192 NIF beams. Targets produced up to 2×10(10) 2.45 MeV neutrons for initial testing of the nTOF detectors. Differences in neutron scattering at the OMEGA laser facility where the detectors were calibrated and at NIF result in different response functions at the two facilities. Monte Carlo modeling shows this difference. The nTOF performance on these early experiments indicates that the nTOF system with its full complement of detectors should perform well in future measurements of yield, temperature, and bang time.