Automatic, fast and robust characterization of noise distributions for diffusion MRI

Knowledge of the noise distribution in magnitude diffusion MRI images is the centerpiece to quantify uncertainties arising from the acquisition process. The use of parallel imaging methods, the number of receiver coils and imaging filters applied by the scanner, amongst other factors, dictate the resulting signal distribution. Accurate estimation beyond textbook Rician or noncentral chi distributions often requires information about the acquisition process (e.g. coils sensitivity maps or reconstruction coefficients), which is not usually available. We introduce a new method where a change of variable naturally gives rise to a particular form of the gamma distribution for background signals. The first moments and maximum likelihood estimators of this gamma distribution explicitly depend on the number of coils, making it possible to estimate all unknown parameters using only the magnitude data. A rejection step is used to make the method automatic and robust to artifacts. Experiments on synthetic datasets show that the proposed method can reliably estimate both the degrees of freedom and the standard deviation. The worst case errors range from below 2% (spatially uniform noise) to approximately 10% (spatially variable noise). Repeated acquisitions of in vivo datasets show that the estimated parameters are stable and have lower variances than compared methods.Comment: v2: added publisher DOI statement, fixed text typo in appendix A

Knowledge, Attitude and Willingness to Participate in Gamete Donation for Artificial Insemination among Undergraduate Students in Lagos

Background: Infertility affects one-fifth to one-sixth of couples of reproductive age. Gamete donation is one option for managing infertility, but it is relatively unknown in the developing world. Objectives: To assess Nigerian undergraduate students' knowledge, attitude and willingness to participate in gamete donation for artificial insemination. Methods: A descriptive cross-sectional study was conducted among 160 undergraduate students using a semi-structured self-administered questionnaire. The respondents were recruited using a multi-stage sampling technique. Results: The mean age of the respondents was 21.5±3.2 years, with a range of 18-32 years. The majority (89.4%) of the respondents were single and were in the first year of study (56.3%). Almost all the respondents (96.3%) had heard about the practice of gamete donation, but only (38.7%) had overall good knowledge about it. Almost half (46.9%) of respondents had an overall positive attitude towards gamete donation, while only 37.5% were willing to participate. The class level of the respondents (p = 0.03) was significantly associated with poor knowledge of gamete donation, while age (p = 0.01) and gender (p < 0.001) were associated with a negative attitude. Age (p<0.001) was also significantly associated with poor willingness to participate. Conclusion: The respondents' awareness of gamete donation was high, but their knowledge was poor, leading to a negative attitude and poor willingness to participate. Public enlightenment on gamete donation for artificial insemination should be intensified

An Exploratory Evaluation of a Treatment Mall at a State Psychiatric Hospital

The Treatment Mall is a model of inpatient psychosocial treatment provided to adults with severe mental illness to deliver recovery-oriented, evidenced-based treatment and has been implemented in state mental hospitals across the United States. The present study is an exploratory evaluation of a recently implemented Treatment Mall in a state mental hospital. To evaluate this program, the experiences of clients (N=28), staff (N=32), and administrators (N=5) were compiled using a quantitative questionnaire and focused on empowerment, skill development, and satisfaction. Additionally, data from the hospital database (N=183) were extracted and analyzed by comparing frequencies of occurrence 90 days before and 90 days after Treatment Mall implementation. The findings indicate that clients reported learning skills and were satisfied with how they were treated at the Treatment Mall. Female clients and staff viewed independent living and recovery possibilities significantly more positively than male clients and staff. Hospital performance indicators showed no significant changes pre to post implementation.

Cohort Profile: The Zurich Project on the Social Development from Childhood to Adulthood (z-proso)

The Zurich Project on the Social Development from Childhood to Adulthood (z-proso) began in 2004 in response to the need for a better evidence base to support optimal child social development and prevent crime and violence. Since then, the study has tracked the development of a diverse sample of youths (N = 1,675 in the target sample; ~50% female) from age 7 (n = 1,360) to age 20 (n = 1,180), with primary data collection waves at ages 7, 8, 9, 10, 11, 12, 13, 15, 17, and 20. The study uses a multi-method, multi-informant design that combines teacher, youth, and parent reports with observational and behavioural measures, biosampling, functional imaging, and ecological momentary assessment. Analyses of the data have contributed important evidence to a diversity of topics in child and adolescent development, illuminating the developmental roots of crime and aggression, the impacts of exposure to different forms and combinations of victimisation, and trajectories of mental health and neurodevelopmental symptoms

Caracterización de depósitos carbonáticos ligados a paleosurgencias en el sector de Batallones-Malcovadeso (Neógeno de la Cuenca de Madrid)

En la zona de canteras de Valdeinfierno, en el sector de Batallones-Malcovadeso, parte centro-meridional de la Cuenca de Madrid, se ha reconocido una serie de depósitos carbonáticos que presentan geometría dómica y estructura interna columnar. Dentro de estos depósitos de carbonato se distinguen dos unidades. La inferior (U2) es mayoritariamente dolomítica y de estructura brechoide, y petrográficamente consiste en dolomicritas con cemento calcítico. La superior (U3) está formada tanto por dolomita como por calcita, y se caracteriza por el desarrollo de morfologías columnares de aspecto travertínico. Petrográficamente, los depósitos de esta unidad consisten en caliza con texturas alveolar y biogénica. Entre las columnas de carbonato se distinguen abundantes masas arcillosas. Hacia la base de estas unidades carbonáticas se sitúa una unidad detrítica (U1), formada por arenas feldespáticas y a su techo se dispone un conjunto lutítico con alguna intercalación carbonática de composición dolomítica (Unidad U4) y, por encima de estas lutitas, un conjunto calizo (Unidad U5). Las arcillas presentes en la unidad U3 tienen una composición (sepiolita > esmectita trioctaédrica ± illita) netamente diferente a las de la unidad U4 (esmectita dioctaédrica > illita ± caolinita). La composición isotópica de los carbonatos de las unidades U2 y U3, así como de los niveles carbonatados de la unidad U4, es bastante similar en el caso de la dolomita, con valores δ13C que oscilan entre –6,21 y –7,78‰ y entre –3,23 y –4,05‰ para el δ18O. Por otro lado, desde un punto de vista de su composición isotópica, se diferencian los carbonatos de la unidad 4 y del techo de la unidad 2, exclusivamente calcíticos, en los que los valores de δ13C oscilan entre –8,07 y –11,75‰, y los de δ18O entre –5,27 y –7,35‰. La calcita existente en los niveles dolomíticos presenta valores intermedios entre los dos grupos anteriores. Los rasgos de la sucesión sedimentaria y los resultados analíticos obtenidos indican una fase de expansión lacustre en la zona estudiada con un cambio en la química de las aguas, todo ello favorecido por la entrada de aguas subterráneas a través de surgencias.Este trabajo se ha realizado dentro del Proyecto de investigación CGL2005-03900/BTE financiado por el Ministerio de Educación y Ciencia.Peer reviewe

LFI 30 and 44 GHz receivers Back-End Modules

The 30 and 44 GHz Back End Modules (BEM) for the Planck Low Frequency Instrument are broadband receivers (20% relative bandwidth) working at room temperature. The signals coming from the Front End Module are amplified, band pass filtered and finally converted to DC by a detector diode. Each receiver has two identical branches following the differential scheme of the Planck radiometers. The BEM design is based on MMIC Low Noise Amplifiers using GaAs P-HEMT devices, microstrip filters and Schottky diode detectors. Their manufacturing development has included elegant breadboard prototypes and finally qualification and flight model units. Electrical, mechanical and environmental tests were carried out for the characterization and verification of the manufactured BEMs. A description of the 30 and 44 GHz Back End Modules of Planck-LFI radiometers is given, with details of the tests done to determine their electrical and environmental performances. The electrical performances of the 30 and 44 GHz Back End Modules: frequency response, effective bandwidth, equivalent noise temperature, 1/f noise and linearity are presented

Macro- and micro- properties of multi-recycled aggregate concrete

ABSTRACT: In a future scenario in which all the concrete is recycled concrete, it will be necessary to recycle the recycled concrete. However, it is known that the recycling of concrete implies a loss of properties. This paper shows an innovative technique, the computerized microtomograph, used to evaluate closed porosity, volume of limestone aggregate fraction and volume of mortar of the multi-recycled aggregate concrete, in order to answer the question: how many times it is possible to recycle concrete? First, the source concrete mix using limestone coarse and fine aggregates was characterized. This mix was crushed to obtain a recycled aggregate that was used to manufacture the 1st generation or current recycled aggregate concrete. After the characterization of this 1st generation concrete, and in the same way, a 2nd and a 3rd generation concrete were obtained and characterized, using recycled aggregates from the 1st and 2nd concrete generations respectively. The evaluation by computerized axial tomography allows to know how the successive recycled affect the properties of the concrete. The results show that it is possible to observe the distribution and quantify the aggregate, cement paste and closed porosity contents of the recycled aggregate concrete showing that 3rd generation recycled concrete shows almost twice as much mortar as 1st generation one and demonstrates that it is only possible to recycle the concrete a finite number of times