Beyond the required LISA free-fall performance: new LISA pathfinder results down to 20 μHz

In the months since the publication of the first results, the noise performance of LISA Pathfinder has improved because of reduced Brownian noise due to the continued decrease in pressure around the test masses, from a better correction of noninertial effects, and from a better calibration of the electrostatic force actuation. In addition, the availability of numerous long noise measurement runs, during which no perturbation is purposely applied to the test masses, has allowed the measurement of noise with good statistics down to 20  μHz. The Letter presents the measured differential acceleration noise figure, which is at (1.74±0.05)  fm s^{-2}/sqrt[Hz] above 2 mHz and (6±1)×10  fm s^{-2}/sqrt[Hz] at 20  μHz, and discusses the physical sources for the measured noise. This performance provides an experimental benchmark demonstrating the ability to realize the low-frequency science potential of the LISA mission, recently selected by the European Space Agency

Sediment geochemistry of streams draining abandoned lead / zinc mines in central Wales: the Afon Twymyn

Purpose Despite the decline of metal mining in the UK during the early 20th century, a substantial legacy of heavy metal contamination persists in river channel and floodplain sediments. Poor sediment quality is likely to impede the achievement of ’good’ chemical and ecological status for surface waters under the European Union Water Framework Directive. This paper examines the environmental legacy of the Dylife lead/zinc mine in the central Wales mining district. Leachable heavy metal concentrations in the bed sediments of the Afon Twymyn are established and the geochemical partitioning, potential mobility and bioavailability of sediment-associated heavy metals are established. Materials and methods Sediment samples were collected from the river bed and dry-sieved into two size fractions (<63 μm and 64–2,000 μm). The fractionated samples were then subjected to a sequential extraction procedure to isolate heavy metals (Pb, Zn, Cu, Cd, Fe, Mn) in three different geochemical phases. Sediment samples were then analysed for heavy metals using ICP-AES. Results and discussion The bed sediment of the Afon Twymyn is grossly polluted with heavy metals. Within the vicinity of the former mine, Pb concentrations are up to 100 times greater than levels reported to have deleterious impacts on aquatic ecology. Most heavy metals exist in the most mobile easily exchangeable and carbonate-bound geochemical phases, potentially posing serious threats to ecological integrity and constituting a significant, secondary, diffuse source of pollution. Metal concentrations decrease sharply downstream of the former mine, although there is a gradual increase in the proportion of readily extractable Zn and Cd. Conclusions Implementation of sediment quality guidelines is important in order to achieve the aims of the Water Framework Directive. Assessments of sediment quality should include measurements of background metal concentrations, river water physico-chemistry and, most importantly, metal mobility and potential bioavailability. Uniformity of sediment guidelines throughout Europe and flexibility of targets with regard to the most heavily contaminated mine sites are recommended

A alteridade como critério para cuidar e educar nutrizes: reflexões filosóficas da prática La alteridad cómo criterio para cuidar y educar las madres que amamantan: refexiones filosoficas de la práctica The alterity as a criterion to care and to educate mothers who breastfeed: philosophical reflections of practice

Este estudo configura-se como um ensaio teórico-filosófico da prática do cuidar-educar nutrizes, embasada no nosso cotidiano profissional e no conceito de alteridade desenvolvido por Emmanuel Lévinas. Traz à tona as inquietudes que povoam nossos pensamentos na busca de um algo a mais no sentido do estabelecimento de um agir mutuamente comprometido no cuidar de mulheres que experenciam o processo de amamentação. Acreditamos que a alteridade é um critério ético fundamental que ao ser removido das relações de cuidado, o diálogo não se estabelece e o cuidado pode não se efetivar, porque o pensamento dominante da normalidade, acaba por anular o ser nutriz, estabelecendo, a priori, a forma de pensar e viver a situação.<br>El presente estudio se un ensayo teórico-filosófico acerca de la práctica del cuidar-educar nutrízes; teniendo como base el cotidiano profesional y el concepto de la alteridad desarrollado por Emmanuel Lévinas. Donde muestran las inquietudes que habitan en nuestros pensamientos frente a la búsqueda siempre de "algo más", en el sentido de establecer una actuación comprometida mutuamente en el cuidar de las mujeres que viven la experiencia del proceso de amamantamiento. Creemos, que la diferencia es uno de los criterios éticos fundamentales el cual, al ser apartado de las relaciones del cuidado, el diálogo no se establece y consecuentemente, el cuidado podría no ser efectivo; por que el pensamiento dominante de la normalidad, termina anulando el ser nutriz.<br>This study is configured as a philosophical-theorical essay about the practice of teaching and educating mothers who are breastfeeding and is based on our professional daily activity and on the concept of alterity developed by Emmanuel Levinas. It broughts to light the disturbance that fill our minds in the search for something bigger in the sense of establishing a mutual obligation in the caring of women that experience the nursing process. We belive that alterity is a fundamental ethical criterion that when removed from care relations disturbs the dialogue and caring may not be effective, because the dominant thinking of normality eliminates the nursing-mother being, establishing a priori, the thinking manner to live a given situation

Association between hospitalization-related outcomes, dynapenia and body mass index: The Glisten Study

Objective To compare the prognostic value of dynapenia, as evaluated by handgrip, and body mass index (BMI) on length of stay (LOS), days of bed rest, and other hospitalization-related outcomes in a population of older adults admitted to 12 italian acute care divisions.Methods Data on age, weight, BMI, comorbidities, ADL, physical activity level, muscle strength, were recorded at hospital admission. LOS, days of bed rest, intrahospital falls, and discharge destination were also recorded during the hospitalization. Subjects with BMI &lt;18.5 kg/m(2) were classified as underweight, subjects with BMI 18.5-24.9 as normal weight, subjects with BMI &gt;= 25 as overweight-obese.Results A total of 634 patients, mean age 80.8 +/- 6.7 years and 49.4% women, were included in the analysis. Overall dynapenic subjects (D) showed a longer period of LOS and bed rest compared with non-dynapenic (ND). When the study population was divided according to BMI categories, underweight (UW), normal weight (NW), and overweight-obese (OW-OB), no significant differences were observed in hospital LOS and days of bed rest. When analysis of covariance was used to determine the difference of LOS across handgrip/BMI groups, D/OW-OB and D/UW subjects showed significantly longer LOS (11.32 and 10.96 days, both p 0.05) compared to ND/NW subjects (7.69 days), even when controlling for age, gender, baseline ADL, cause of hospitalization and comorbidity. After controlling for the same confounding factors, D/OW-OB, D/NW and D/UW subjects showed significantly longer bed rest (4.7, 4.56, and 4.05 days, respectively, all p 0.05, but D/OWOB p 0.01) compared to ND/NW subjects (1.59 days).Conclusion In our study population, LOS is longer in D/UW and D/OW-OB compared to ND/NW subjects and days of bed rest are mainly influenced by dynapenia, and not by BMI class

LISA Pathfinder: the experiment and the route to LISA

LISA Pathfinder (LPF) is a science and technology demonstrator planned by the European Space Agency in view of the LISA mission. As a scientific payload, the LISA Technology Package on board LPF will be the most precise geodesics explorer flown as of today, both in terms of displacement and acceleration sensitivity. The challenges embodied by LPF make it a unique mission, paving the way towards the space-borne detection of gravitational waves with LISA. This paper summarizes the basics of LPF, and the progress made in preparing its effective implementation in flight. We hereby give an overview of the experiment philosophy and assumptions to carry on the measurement. We report on the mission plan and hardware design advances and on the progress on detailing measurements and operations. Some light will be shed on the related data processing algorithms. In particular, we show how to single out the acceleration noise from the spacecraft motion perturbations, how to account for dynamical deformation parameters distorting the measurement reference and how to decouple the actuation noise via parabolic free flight

LISA Pathfinder platform stability and drag-free performance

The science operations of the LISA Pathfinder mission have demonstrated the feasibility of sub-femto-g free fall of macroscopic test masses necessary to build a gravitational wave observatory in space such as LISA. While the main focus of interest, i.e., the optical axis or the x-axis, has been extensively studied, it is also of great importance to evaluate the stability of the spacecraft with respect to all the other degrees of freedom (d.o.f.). The current paper is dedicated to such a study: the exhaustive and quantitative evaluation of the imperfections and dynamical effects that impact the stability with respect to its local geodesic. A model of the complete closed-loop system provides a comprehensive understanding of each component of the in-loop coordinates spectral density. As will be presented, this model gives very good agreement with LISA Pathfinder flight data. It allows one to identify the noise source at the origin and the physical phenomena underlying the couplings. From this, the stability performance of the spacecraft with respect to its geodesic is extracted as a function of frequency. Close to 1 mHz, the stability of the spacecraft on the XSC, YSC and ZSC d.o.f. is shown to be of the order of 5.0×10−15  m s−2 Hz−1/2 for X, 6.0×10−14  m s−2 Hz−1/2 for Y, and 4.0×10−14  m s−2 Hz−1/2 for Z. For the angular d.o.f., the values are of the order of 3×10−12  rad s−2  Hz−1/2 for ΘSC, 5×10−13  rad s−2  Hz−1/2 for HSC, and 3×10−13  rad s−2  Hz−1/2 for ΦSC. Below 1 mHz, however, the stability performances are worsened significantly by the effect of the star tracker noise on the closed-loop system. It is worth noting that LISA is expected to be spared from such concerns, as differential wave-front sensing, an attitude sensor system of much higher precision, will be utilized for attitude control

LISA pathfinder performance confirmed in an open-loop configuration: results from the free-fall actuation mode

We report on the results of the LISA Pathfinder (LPF) free-fall mode experiment, in which the control force needed to compensate the quasistatic differential force acting on two test masses is applied intermittently as a series of “impulse” forces lasting a few seconds and separated by roughly 350 s periods of true free fall. This represents an alternative to the normal LPF mode of operation in which this balancing force is applied continuously, with the advantage that the acceleration noise during free fall is measured in the absence of the actuation force, thus eliminating associated noise and force calibration errors. The differential acceleration noise measurement presented here with the free-fall mode agrees with noise measured with the continuous actuation scheme, representing an important and independent confirmation of the LPF result. An additional measurement with larger actuation forces also shows that the technique can be used to eliminate actuation noise when this is a dominant factor