Do low-fat foods alter risk of colorectal cancer from processed meat?

OBJECTIVES: We investigated potential causes of the high incidence rate of colorectal cancer (CRC) in New Zealand. STUDY DESIGN: A national population-based case-control study of 806 cases and 1025 controls was conducted to determine the risk factors for CRC in this population. METHODS: Information about family history of CRC, ethnicity, diet, school milk consumption, exercise, and height and weight at age 20 years were collected by a self-administered questionnaire from cases and controls. RESULTS: Response rates were 84% for cases and 65% for controls. Increasing preference for low-fat food alternatives was associated with reducing odds ratios (OR) for CRC (Ptrend<0.001) with a considerably reduced OR of always versus never choosing low-fat food alternatives (OR = 0.39, 95% confidence interval = 0.26, 0.58). Increased consumption of dairy products or milk was associated with reduced risk of CRC. Belonging to the male gender, having a first degree relative with CRC, and increasing consumption of processed meat, lamb, pork, and bread were associated with elevated risks of CRC. The increased risk from consumption of processed meat was not evident in subjects who regularly or always preferred low-fat food. CONCLUSIONS: A preference for low-fat food may ameliorate an increased risk of CRC from the consumption of processed meat.

Enhancing bowel screening: Preventing colorectal cancer by flexible sigmoidoscopy in New Zealand.

OBJECTIVES: The prevention of colorectal cancer (CRC) attainable from introducing once-in-a-lifetime flexible sigmoidoscopy (FSIG) screening was assessed. STUDY DESIGN: This is a review of relevant available information for the assessment of the impact and resource demands of FSIG in New Zealand. METHODS: The reduction in bowel cancer incidence achievable by one-off FSIG screening from 50 to 59 years of age, an age group for which bowel screening is not currently offered, was reviewed. The prevention of CRC attainable from an offer of screening at 55 years of age in New Zealand was also estimated. The number and cost of the FSIG screening procedures required and referrals for colonoscopies and the savings in treatment were calculated. RESULTS: Annually, about 27,500 FSIG screening procedures would be required if 50% of those turning 55 years of age accepted an offer of once-in-a-lifetime FSIG screening. This would result in three-four-fold fewer people being referred for colonoscopy than in the national 2-yearly faecal immunochemical test (FIT) screening programme and subsequently reduce demand for colonoscopy from a false-positive FIT. The number of CRC cases prevented would increase over 17 years to more than 300 per year by 2033. After 10-15 years of screening, the annual savings in health service costs, primarily from CRC prevented, were sufficient to completely fund the FSIG screening. CONCLUSIONS: Inclusion of FSIG screening in the national bowel screening programme would significantly reduce both the incidence and mortality of CRC in New Zealand, reduce the colonoscopy demand of current bowel screening and reduce long-term health service costs.

Nonlinear ultrasound simulation in an axisymmetric coordinate system using a k-space pseudospectral method.

A full-wave model for nonlinear ultrasound propagation through a heterogeneous and absorbing medium in an axisymmetric coordinate system is developed. The model equations are solved using a nonstandard or k-space pseudospectral time domain method. Spatial gradients in the axial direction are calculated using the Fourier collocation spectral method, and spatial gradients in the radial direction are calculated using discrete trigonometric transforms. Time integration is performed using a k-space corrected finite difference scheme. This scheme is exact for plane waves propagating linearly in the axial direction in a homogeneous and lossless medium and significantly reduces numerical dispersion in the more general case. The implementation of the model is described, and performance benchmarks are given for a range of grid sizes. The model is validated by comparison with several analytical solutions. This includes one-dimensional absorption and nonlinearity, the pressure field generated by plane-piston and bowl transducers, and the scattering of a plane wave by a sphere. The general utility of the model is then demonstrated by simulating nonlinear transcranial ultrasound using a simplified head model.

Treating a novel plasticity defect rescues episodic memory in Fragile X model mice.

Episodic memory, a fundamental component of human cognition, is significantly impaired in autism. We believe we report the first evidence for this problem in the Fmr1-knockout (KO) mouse model of Fragile X syndrome and describe potentially treatable underlying causes. The hippocampus is critical for the formation and use of episodes, with semantic (cue identity) information relayed to the structure via the lateral perforant path (LPP). The unusual form of synaptic plasticity expressed by the LPP (lppLTP) was profoundly impaired in Fmr1-KOs relative to wild-type mice. Two factors contributed to this defect: (i) reduced GluN1 subunit levels in synaptic NMDA receptors and related currents, and (ii) impaired retrograde synaptic signaling by the endocannabinoid 2-arachidonoylglycerol (2-AG). Studies using a novel serial cue paradigm showed that episodic encoding is dependent on both the LPP and the endocannabinoid receptor CB1, and is strikingly impaired in Fmr1-KOs. Enhancing 2-AG signaling rescued both lppLTP and learning in the mutants. Thus, two consequences of the Fragile-X mutation converge on plasticity at one site in hippocampus to prevent encoding of a basic element of cognitive memory. Collectively, the results suggest a clinically plausible approach to treatment.

Representing arbitrary acoustic source and sensor distributions in Fourier collocation methods.

Accurately representing acoustic source distributions is an important part of ultrasound simulation. This is challenging for grid-based collocation methods when such distributions do not coincide with the grid points, for instance when the source is a curved, two-dimensional surface embedded in a three-dimensional domain. Typically, grid points close to the source surface are defined as source points, but this can result in "staircasing" and substantial errors in the resulting acoustic fields. This paper describes a technique for accurately representing arbitrary source distributions within Fourier collocation methods. The method works by applying a discrete, band-limiting convolution operator to the continuous source distribution, after which source grid weights can be generated. This allows arbitrarily shaped sources, for example, focused bowls and circular pistons, to be defined on the grid without staircasing errors. The technique is examined through simulations of a range of ultrasound sources, and comparisons with analytical solutions show excellent accuracy and convergence rates. Extensions of the technique are also discussed, including application to initial value problems, distributed sensors, and moving sources.

Rapid calculation of acoustic fields from arbitrary continuous-wave sources.

A Green's function solution is derived for calculating the acoustic field generated by phased array transducers of arbitrary shape when driven by a single frequency continuous wave excitation with spatially varying amplitude and phase. The solution is based on the Green's function for the homogeneous wave equation expressed in the spatial frequency domain or k-space. The temporal convolution integral is solved analytically, and the remaining integrals are expressed in the form of the spatial Fourier transform. This allows the acoustic pressure for all spatial positions to be calculated in a single step using two fast Fourier transforms. The model is demonstrated through several numerical examples, including single element rectangular and spherically focused bowl transducers, and multi-element linear and hemispherical arrays.

Time domain reconstruction of sound speed and attenuation in ultrasound computed tomography using full wave inversion.

Ultrasound computed tomography (USCT) is a non-invasive imaging technique that provides information about the acoustic properties of soft tissues in the body, such as the speed of sound (SS) and acoustic attenuation (AA). Knowledge of these properties can improve the discrimination between benign and malignant masses, especially in breast cancer studies. Full wave inversion (FWI) methods for image reconstruction in USCT provide the best image quality compared to more approximate methods. Using FWI, the SS is usually recovered in the time domain, and the AA is usually recovered in the frequency domain. Nevertheless, as both properties can be obtained from the same data, it is desirable to have a common framework to reconstruct both distributions. In this work, an algorithm is proposed to reconstruct both the SS and AA distributions using a time domain FWI methodology based on the fractional Laplacian wave equation, an adjoint field formulation, and a gradient-descent method. The optimization code employs a Compute Unified Device Architecture version of the software k-Wave, which provides high computational efficiency. The performance of the method was evaluated using simulated noisy data from numerical breast phantoms. Errors were less than 0.5% in the recovered SS and 10% in the AA.

Enhanced Recovery After Surgery (ERAS) for gastrointestinal surgery, part 2: consensus statement for anaesthesia practice.

BACKGROUND: The present interdisciplinary consensus review proposes clinical considerations and recommendations for anaesthetic practice in patients undergoing gastrointestinal surgery with an Enhanced Recovery after Surgery (ERAS) programme. METHODS: Studies were selected with particular attention being paid to meta-analyses, randomized controlled trials and large prospective cohort studies. For each item of the perioperative treatment pathway, available English-language literature was examined and reviewed. The group reached a consensus recommendation after critical appraisal of the literature. RESULTS: This consensus statement demonstrates that anaesthesiologists control several preoperative, intraoperative and postoperative ERAS elements. Further research is needed to verify the strength of these recommendations. CONCLUSIONS: Based on the evidence available for each element of perioperative care pathways, the Enhanced Recovery After Surgery (ERAS®) Society presents a comprehensive consensus review, clinical considerations and recommendations for anaesthesia care in patients undergoing gastrointestinal surgery within an ERAS programme. This unified protocol facilitates involvement of anaesthesiologists in the implementation of the ERAS programmes and allows for comparison between centres and it eventually might facilitate the design of multi-institutional prospective and adequately powered randomized trials.

Genetic variation in immunoglobulin G receptor affects survival after lung transplantation.

Chronic rejection remains the most important complication after lung transplantation (LTx). There is mounting evidence that both rheumatoid arthritis and chronic rejection share similar inflammatory mechanisms. As genetic variants in the FCGR2A gene that encodes the immunoglobulin gamma receptor (IgGR) have been identified in rheumatoid arthritis, we investigated the relationship between a genetic variant in the IgGR gene and chronic rejection and mortality after LTx. Recipient DNA from blood or explant lung tissue of 418 LTx recipients was evaluated for the IgGR (rs12746613) polymorphism. Multivariate analysis was carried out, correcting for several co-variants. In total, 216 patients had the CC-genotype (52%), 137 had the CT-genotype (33%) and 65 had the TT-genotype (15%). Univariate analysis demonstrated higher mortality in the TT-genotype compared with both other genotypes (p < 0.0001). Multivariate analysis showed that the TT-genotype had worse survival compared with the CC-genotype (hazard ratio [HR] = 2.26, p = 0.0002) but no significance was observed in the CT-genotype (HR = 1.32, p = 0.18). No difference was seen for chronic rejection. The TT-genotype demonstrated more respiratory infections (total, p = 0.037; per patient, p = 0.0022) compared with the other genotypes. A genetic variant in the IgGR is associated with higher mortality and more respiratory infections, although not with increased prevalence of chronic rejection, after LTx.

Azithromycin and the treatment of lymphocytic airway inflammation after lung transplantation.

Lymphocytic airway inflammation is a major risk factor for chronic lung allograft dysfunction, for which there is no established treatment. We investigated whether azithromycin could control lymphocytic airway inflammation and improve allograft function. Fifteen lung transplant recipients demonstrating acute allograft dysfunction due to isolated lymphocytic airway inflammation were prospectively treated with azithromycin for at least 6 months (NCT01109160). Spirometry (FVC, FEV1 , FEF25-75 , Tiffeneau index) and FeNO were assessed before and up to 12 months after initiation of azithromycin. Radiologic features, local inflammation assessed on airway biopsy (rejection score, IL-17(+) cells/mm(2) lamina propria) and broncho-alveolar lavage fluid (total and differential cell counts, chemokine and cytokine levels); as well as systemic C-reactive protein levels were compared between baseline and after 3 months of treatment. Airflow improved and FeNO decreased to baseline levels after 1 month of azithromycin and were sustained thereafter. After 3 months of treatment, radiologic abnormalities, submucosal cellular inflammation, lavage protein levels of IL-1ß, IL-8/CXCL-8, IP-10/CXCL-10, RANTES/CCL5, MIP1-α/CCL3, MIP-1ß/CCL4, Eotaxin, PDGF-BB, total cell count, neutrophils and eosinophils, as well as plasma C-reactive protein levels all significantly decreased compared to baseline (p < 0.05). Administration of azithromycin was associated with suppression of posttransplant lymphocytic airway inflammation and clinical improvement in lung allograft function.

Modeling power law absorption and dispersion in viscoelastic solids using a split-field and the fractional Laplacian.

The absorption of compressional and shear waves in many viscoelastic solids has been experimentally shown to follow a frequency power law. It is now well established that this type of loss behavior can be modeled using fractional derivatives. However, previous fractional constitutive equations for viscoelastic media are based on temporal fractional derivatives. These operators are non-local in time, which makes them difficult to compute in a memory efficient manner. Here, a fractional Kelvin-Voigt model is derived based on the fractional Laplacian. This is obtained by splitting the particle velocity into compressional and shear components using a dyadic wavenumber tensor. This allows the temporal fractional derivatives in the Kelvin-Voigt model to be replaced with spatial fractional derivatives using a lossless dispersion relation with the appropriate compressional or shear wave speed. The model is discretized using the Fourier collocation spectral method, which allows the fractional operators to be efficiently computed. The field splitting also allows the use of a k-space corrected finite difference scheme for time integration to minimize numerical dispersion. The absorption and dispersion behavior of the fractional Laplacian model is analyzed for both high and low loss materials. The accuracy and utility of the model is then demonstrated through several numerical experiments, including the transmission of focused ultrasound waves through the skull.

Polymyxa graminis Isolates from Australia: Identification in Wheat Roots and Soil, Molecular Characterization, and Wide Genetic Diversity.

Polymyxa graminis is an obligate parasite of roots and an important vector of viruses that damage cereal crops in different parts of the world. In 2011 and 2012, P. graminis was identified infecting 11 wheat root samples from three widely dispersed locations in southwest Australia. Its presence was detected by polymerase chain reaction (PCR) and confirmed by DNA sequencing of the transcribed regions of its ribosomal RNA genes (rDNA) and observing sporosori of characteristic morphology and size in stained wheat roots. Also, when soil samples were collected from two locations where P. graminis was found and wheat bait plants grown in them, P. graminis was detected in their roots by PCR. Ribosomal DNA sequences of six southwest Australian isolates were obtained from wheat roots, and one northeast Australian isolate from barley roots. When these seven P. graminis sequences were compared with others from GenBank by phylogenetic analysis, three southwest Australian isolates were classified as P. graminis f. sp. temperata (ribotypes Ia and Ib), and three as f. sp. tepida (ribotypes IIa and IIb). P. graminis f. sp. temperata and tepida both occur in temperate growing regions of other continents and are associated with transmission of soil-borne viruses to cereal crops. The P. graminis isolate from northeast Australia was sufficiently distinct from the five existing sequence groups for it to be placed into a newly proposed grouping, ribotype VI, which also included an isolate from tropical West Africa. However, when randomly collected wheat leaf samples from 39 field crops from 27 widely dispersed locations, 21 individual wheat plant samples collected from low lying areas within 21 fields at 11 locations, and wheat bait plants growing in five soil samples from two locations were tested by reverse transcription (RT)-PCR for the presence of Soil-borne wheat mosaic virus, Soil-borne cereal mosaic virus, Wheat spindle streak mosaic virus, and furoviruses in general, no virus infection was detected. These findings suggest at least three P. graminis introductions into Australia, and the occurrence of f. sp. temperata (ribotype I) and f. sp. tepida (ribotype II) suggests that, if not already present, soil-borne cereal viruses are likely to become established should they become introduced to the continent in the future.

First Report of Wheat mosaic virus Infecting Wheat in Western Australia.

In eastern Australia, there have been several as yet unconfirmed reports of Wheat mosaic virus (WMoV) infecting wheat (3). WMoV, previously known as High plains virus (HPV), is transmitted by the wheat curl mite (WCM, Aceria tosichella). It is often found in mixed infections with Wheat streak mosaic virus (WSMV), also transmitted by WCM (2,3). WSMV was first identified in Australia in 2003 (3). In October 2012, stunted wheat plants with severe yellow leaf streaking were common in a field experiment near Corrigin in Western Australia consisting of nine wheat cultivars. These symptoms were also common in two commercial crops of wheat cv. Mace near Kulin. Leaf samples (one per plant) from each location were tested by ELISA using specific antiserum to WMoV (syn. HPV 17200, Agdia, Elkhart, IN). At the field experiment, 20 leaf samples were collected at random from each wheat plot (4 replicates) and tested individually by ELISA. WMoV incidence was 5% for cv. Yipti, 16% for cvs Emu Rock, Wyalkatchem and Mace, 22% for cvs. Corack, Fortune, Calingiri, and Magenta, and 55% for cv. Cobra. From the two commercial wheat crops, 100 leaf samples were collected at random from each and tested by ELISA. WMoV incidence was 2 and 4%. In addition, 50 leaf samples of Hordeum leporinum (barley grass) and 20 of Lolium rigidum (annual ryegrass) were collected and tested by ELISA. WMoV incidence was 2% in H. leporinum, but 0% in L. rigidum. Infected H. leporinum plants were symptomless. Symptomatic wheat leaf samples from both sites were tested by RT-PCR using WMoV specific primers designed from its RNA3 sequence (1). The PCR products (339 bp) were sequenced and lodged in GenBank (Accession Nos KC337341 and KC337342). WMoV isolates from Corrigin (WA-CG12) and Kulin (WA-KU12) had identical sequences. When the nucleic acid sequences of WA-CG12 and WA-KU12 were compared with those of the three other WMoV isolates on GenBank, they had 100% nucleotide sequence identity with a Nebraska isolate (U60141), and 99.7% identity to two United States sweet corn isolates (AY836524 and AY836525). Ten symptomatic wheat plants were collected from each location, transplanted into pots and leaf samples tested individually for WMoV and WSMV (07048, Loewe, Germany) by ELISA. All were infected with both viruses and infested with WCM. WCM-infested glumes (>10 WCM/glume) were placed on the leaf sheaths of 60 wheat plants cv. Calingiri (35 with WA-CG12 and 25 with WA-KU12) and 13 sweet corn plants cv. Snow Gold (WA-CG12 only). In addition, 20 wheat and 10 sweet corn plants were left without infested glumes to be uninoculated controls. All 60 WCM-inoculated wheat plants became stunted with severe leaf streaking. When leaf samples from each plant were tested by ELISA 18 to 30 days later, both viruses were detected. WMoV was detected in all 13 WCM-inoculated sweet corn plants and WSMV in two of them. Plants with WMoV alone initially had short chlorotic leaf streaks that subsequently combined, causing broad streaks. These are typical WMoV symptoms for sweet corn (1). No symptoms developed and no virus was detected in any of the uninoculated wheat or sweet corn control plants. The WMoV nucleotide sequence obtained from an infected sweet corn plant was identical to those of WA-CG12 and WA-KU12. To our knowledge, this is the first confirmed report of WMoV presence in Australia. References: (1) B. S. M. Lebas et al. Plant Dis. 89:1103, 2005. (2) D. Navia et al. Exp. Appl. Acarol. 59:95, 2013. (3) J. M. Skare et al. Virology 347:343, 2006.

Variation in care and outcome for fragile hip fracture patients: a European multicentre study benchmarking fulfilment of established quality indicators.

PURPOSE: Despite the availability of clinical guidelines for hip fracture patients, adherence to these guidelines is challenging, potentially resulting in suboptimal patient care. The goal of this study was (1) to evaluate and benchmark the adherence to recently established quality indicators (QIs), and (2) to study clinical outcomes, in fragile hip fracture patients from different European countries. METHODS: This observational, cross-sectional multicenter study was performed in 10 hospitals from 9 European countries including data of 298 consecutive patients. RESULTS: A large variation both within and between hospitals were seen regarding adherence to the individual QIs. QIs with the lowest overall adherence rates were the administration of systemic steroids (5.4%) and tranexamic acid (20.1%). Indicators with the highest adherence rates (above 95%) were pre-operative (99.3%) and post-operative haemoglobin level assessment (100%). The overall median time to surgery was 22.6 h (range 15.7-42.5 h). The median LOS was 9.0 days (range 5.0-19.0 days). The most common complications were delirium (23.2%) and postsurgical constipation (25.2%). CONCLUSION: The present study shows large variation in the care for fragile patients with hip fractures indicating room for improvement. Therefore, hospitals should invest in benchmarking and knowledge-sharing. Large quality improvement initiatives with longitudinal follow up of both process and outcome indicators should be initiated.

AKAP150-anchored PKA regulation of synaptic transmission and plasticity, neuronal excitability and CRF neuromodulation in the lateral habenula.

Numerous studies of hippocampal synaptic function in learning and memory have established the functional significance of the scaffolding A-kinase anchoring protein 150 (AKAP150) in kinase and phosphatase regulation of synaptic receptor and ion channel trafficking/function and hence synaptic transmission/plasticity, and neuronal excitability. Emerging evidence also suggests that AKAP150 signaling may play a critical role in brain's processing of rewarding/aversive experiences. Here we focused on an unexplored role of AKAP150 in the lateral habenula (LHb), a diencephalic brain region that integrates and relays negative reward signals from forebrain striatal and limbic structures to midbrain monoaminergic centers. LHb aberrant activity (specifically hyperactivity) is also linked to depression. Using whole cell patch clamp recordings in LHb of male wildtype (WT) and ΔPKA knockin mice (with deficiency in AKAP-anchoring of PKA), we found that the genetic disruption of PKA anchoring to AKAP150 significantly reduced AMPA receptor (AMPAR)-mediated glutamatergic transmission and prevented the induction of presynaptic endocannabinoid (eCB)-mediated long-term depression (LTD) in LHb neurons. Moreover, ΔPKA mutation potentiated GABAA receptor (GABAAR)-mediated inhibitory transmission postsynaptically while increasing LHb intrinsic neuronal excitability through suppression of medium afterhyperpolarizations (mAHPs). Given that LHb is a highly stress-responsive brain region, we further tested the effects of corticotropin releasing factor (CRF) stress neuromodulator on synaptic transmission and intrinsic excitability of LHb neurons in WT and ΔPKA mice. As in our earlier study in rat LHb, CRF significantly suppressed GABAergic transmission onto LHb neurons and increased intrinsic excitability by diminishing small-conductance potassium (SK) channel-mediated mAHPs. ΔPKA mutation-induced suppression of mAHPs also blunted the synaptic and neuroexcitatory actions of CRF in mouse LHb. Altogether, our data suggest that AKAP150 complex signaling plays a critical role in regulation of AMPAR and GABAAR synaptic strength, glutamatergic plasticity and CRF neuromodulation possibly through AMPAR and potassium channel trafficking and eCB signaling within the LHb.

A first-order k-space model for elastic wave propagation in heterogeneous media.

A pseudospectral model of linear elastic wave propagation is described based on the first order stress-velocity equations of elastodynamics. k-space adjustments to the spectral gradient calculations are derived from the dyadic Green's function solution to the second-order elastic wave equation and used to (a) ensure the solution is exact for homogeneous wave propagation for timesteps of arbitrarily large size, and (b) also allows larger time steps without loss of accuracy in heterogeneous media. The formulation in k-space allows the wavefield to be split easily into compressional and shear parts. A perfectly matched layer (PML) absorbing boundary condition was developed to effectively impose a radiation condition on the wavefield. The staggered grid, which is essential for accurate simulations, is described, along with other practical details of the implementation. The model is verified through comparison with exact solutions for canonical examples and further examples are given to show the efficiency of the method for practical problems. The efficiency of the model is by virtue of the reduced point-per-wavelength requirement, the use of the fast Fourier transform (FFT) to calculate the gradients in k space, and larger time steps made possible by the k-space adjustments.

Modeling nonlinear ultrasound propagation in heterogeneous media with power law absorption using a k-space pseudospectral method.

The simulation of nonlinear ultrasound propagation through tissue realistic media has a wide range of practical applications. However, this is a computationally difficult problem due to the large size of the computational domain compared to the acoustic wavelength. Here, the k-space pseudospectral method is used to reduce the number of grid points required per wavelength for accurate simulations. The model is based on coupled first-order acoustic equations valid for nonlinear wave propagation in heterogeneous media with power law absorption. These are derived from the equations of fluid mechanics and include a pressure-density relation that incorporates the effects of nonlinearity, power law absorption, and medium heterogeneities. The additional terms accounting for convective nonlinearity and power law absorption are expressed as spatial gradients making them efficient to numerically encode. The governing equations are then discretized using a k-space pseudospectral technique in which the spatial gradients are computed using the Fourier-collocation method. This increases the accuracy of the gradient calculation and thus relaxes the requirement for dense computational grids compared to conventional finite difference methods. The accuracy and utility of the developed model is demonstrated via several numerical experiments, including the 3D simulation of the beam pattern from a clinical ultrasound probe.

A review of the microtremor horizontal-to-vertical spectral ratio (MHVSR) method.

The single-station microtremor horizontal-to-vertical spectral ratio (MHVSR) method was initially proposed to retrieve the site amplification function and its resonance frequencies produced by unconsolidated sediments overlying high-velocity bedrock. Presently, MHVSR measurements are predominantly conducted to obtain an estimate of the fundamental site frequency at sites where a strong subsurface impedance contrast exists. Of the earthquake site characterization methods presented in this special issue, the MHVSR method is the furthest behind in terms of consensus towards standardized guidelines and commercial use. The greatest challenges to an international standardization of MHVSR acquisition and analysis are (1) the what - the underlying composition of the microtremor wavefield is site-dependent, and thus, the appropriate theoretical (forward) model for inversion is still debated; and (2) the how - many factors and options are involved in the data acquisition, processing, and interpretation stages. This paper reviews briefly a historical development of the MHVSR technique and the physical basis of an MHVSR (the what). We then summarize recommendations for MHVSR acquisition and analysis (the how). Specific sections address MHVSR interpretation and uncertainty assessment.

Search for the rare decays K(L)→π0π0µ+µ- and K(L)→π0π0X0→π0π0µ+µ-.

The KTeV E799 experiment has conducted a search for the rare decays, K(L)→π(0)π(0)µ(+)µ(-) and K(L)→π(0)π(0)X(0)→π(0)π(0)µ(+)µ(-), where the X(0) is a possible new neutral boson that was reported by the HyperCP experiment with a mass of (214.3 ± 0.5) MeV/c(2). We find no evidence for either decay. We obtain upper limits of Br(K(L)→π(0)π(0)X(0)→π(0)π(0)µ(+)µ(-)) < 1.0 × 10(-10) and Br(K(L)→π(0)π(0)µ(+)µ(-)) < 9.2 × 10(-11) at the 90% confidence level. This result rules out the pseudoscalar X(0) as an explanation of the HyperCP result under the scenario that the dsX(0) coupling is completely real.