Radio science ground data system for the Voyager-Neptune encounter, part 1

The Voyager radio science experiments at Neptune required the creation of a ground data system array that includes a Deep Space Network complex, the Parkes Radio Observatory, and the Usuda deep space tracking station. The performance requirements were based on experience with the previous Voyager encounters, as well as the scientific goals at Neptune. The requirements were stricter than those of the Uranus encounter because of the need to avoid the phase-stability problems experienced during that encounter and because the spacecraft flyby was faster and closer to the planet than previous encounters. The primary requirement on the instrument was to recover the phase and amplitude of the S- and X-band (2.3 and 8.4 GHz) signals under the dynamic conditions encountered during the occultations. The primary receiver type for the measurements was open loop with high phase-noise and frequency stability performance. The receiver filter bandwidth was predetermined based on the spacecraft's trajectory and frequency uncertainties

Abnormal Response of Costal Chondrocytes to Acidosis in Patients with Chest Wall Deformity

Costal cartilage is much understudied compared to the load bearing cartilages. Abnormally grown costal cartilages are associated with the inherited chest wall deformities pectus excavatum and pectus carinatum resulting in sunken or pigeon chest respectively. A lack of understanding of the ultrastructural and molecular biology properties of costal cartilage is a major confounder in predicting causes and outcomes of these disorders. Due to the avascular nature of cartilage, chondrocytes metabolize glycolytically, producing an acidic environment. During physical activity hydrogen ions move within cartilage driven by compressive forces, thus at any one time, chondrocytes experience transient changes in pH. A variety of ion channels on chondrocytes plasma membrane equip them to function in the rapidly changing conditions they experience. In this paper we describe reduced expression of the ASIC2 gene encoding the acid sensing ion channel isoform 2 (previously referred to as ACCN1 or ACCN) in patients with chest wall deformities. We hypothesized that chondrocytes from these patients cannot respond normally to changes in pH that are an integral part of the biology of this tissue. Activation of ASICs indirectly creates a cascade ultimately dependent on intracellular calcium transients. The objective of this paper was to compare internal calcium signaling in response to external pH changes in costal chondrocytes from patients with chest wall deformities and healthy individuals. Although the molecular mechanism through which chondrocytes are regulated by acidosis remains unknown, we observed reduced amplitudes of calcium rise in patient chondrocytes exposed to low pH that become further impaired upon repeat exposure

Vector-valued weakly analytic measures

The final version of this paper appears in "Hokkaido Mathematical Journal" 27 (1998): 457-473. Print.This paper studies properties of weakly analytic vector-valued measures, an area of study which is relatively unexplored, especially in comparison with scalar-valued measures

Geophysical Exploration of Vesta

Dawn’s year-long stay at Vesta allows comprehensive mapping of the shape, topography, geology, mineralogy, elemental abundances, and gravity field using it’s three instruments and highprecision spacecraft navigation. In the current Low Altitude Mapping Orbit (LAMO), tracking data is being acquired to develop a gravity field expected to be accurate to degree and order ~20 [1, 2]. Multi-angle imaging in the Survey and High Altitude Mapping Orbit (HAMO) has provided adequate stereo coverage to develop a shape model accurate to ~10 m at 100 m horizontal spatial resolution. Accurate mass determination combined with the shape yields a more precise value of bulk density, albeit with some uncertainty resulting from the unmeasured seasonally-dark north polar region. The shape and gravity of Vesta can be used to infer the interior density structure and investigate the nature of the crust, informing models for Vesta’s formation and evolution

The Study of the Pioneer Anomaly: New Data and Objectives for New Investigation

Radiometric tracking data from Pioneer 10 and 11 spacecraft has consistently indicated the presence of a small, anomalous, Doppler frequency drift, uniformly changing with a rate of ~6 x 10^{-9} Hz/s; the drift can be interpreted as a constant sunward acceleration of each particular spacecraft of a_P = (8.74 \pm 1.33) x 10^{-10} m/s^2. This signal is known as the Pioneer anomaly; the nature of this anomaly remains unexplained. We discuss the efforts to retrieve the entire data sets of the Pioneer 10/11 radiometric Doppler data. We also report on the recently recovered telemetry files that may be used to reconstruct the engineering history of both spacecraft using original project documentation and newly developed software tools. We discuss possible ways to further investigate the discovered effect using these telemetry files in conjunction with the analysis of the much extended Doppler data. We present the main objectives of new upcoming study of the Pioneer anomaly, namely i) analysis of the early data that could yield the direction of the anomaly, ii) analysis of planetary encounters, that should tell more about the onset of the anomaly, iii) analysis of the entire dataset, to better determine the anomaly's temporal behavior, iv) comparative analysis of individual anomalous accelerations for the two Pioneers, v) the detailed study of on-board systematics, and vi) development of a thermal-electric-dynamical model using on-board telemetry. The outlined strategy may allow for a higher accuracy solution for a_P and, possibly, will lead to an unambiguous determination of the origin of the Pioneer anomaly.Comment: 43 pages, 40 figures, 3 tables, minor changes before publicatio

Effects of candesartan cilexetil on carotid remodeling in hypertensive diabetic patients: the MITEC study

In hypertension and diabetes, early structural changes of the arterial wall precede or support atherosclerosis. There is evidence that some antihypertensive drugs exert an antiathero-sclerotic effect. Over 36 months, we investigated the effect of candesartan cilexetil (CC) on the common carotid intima-media thickness (IMT) vs amlodipine besylate (AML) in patients with type 2 diabetes and mild to moderate essential hypertension. After a 4-week wash-out period, 209 patients were randomized to either CC 8 mg or AML 5 mg once daily for a minimum of 1 month, after which, if BP was not normalized, the dosage was doubled, followed by the addition of hydrochlorothiazide 12.5 mg if necessary. No significant differences were observed between the two groups for change in IMT at M12 (−0.001 vs −0.027 mm/year for CC and AML respectively, p = 0.425), at M24 (−0.033 vs −0.019 mm per year respectively, p = 0.442), and at the last visit (−0.016 vs −0.039 mm per year respectively, p = 0.549). Within the group, comparisons did not show a significant difference in changes in IMT from baseline to the three visits. At the last visit, IMT regression was observed in 52.2% of patients receiving CC and in 51.3% of those receiving AML (p = 0.908). The augmentation in carotid lumen diameter from baseline was statistically greater in the AML group at the last visit (p = 0.034). BP variations during the study were similar in the two groups. The results of this study show that CC and AML treatments may alter identically the natural progression of carotid IMT in hypertensive type 2 diabetic patients

Presence and Localization of Pro-and Mature Forms of Biglycan and Decorin in Human Costal Cartilage Derived from Chest Wall Deformities

Costal cartilage is a type of hyaline cartilage that forms rod-like structures that connect the ribs to the sternum. The most common chest wall deformities, pectus excavatum and pectus carinatum involved efective costal cartilage resulting in sternal displacement. Costal cartilage is not widely studied leaving little insight into possible factors involved in the pathogenesis of these pectus deformities. This study focused on the presence and distribution of two important regulators of collagen fibrillogenesis and organization, biglycan and decorin. Immunohistochemical analysis of transverse cross sections of normal and deformed costal cartilage revealed that biglycan and decorin mainly localized in the territorial matrix except for prodecorin which was only found within chondrocytes. Western blot analysis of whole protein extracts demonstrated the presence of both pro and mature forms of biglycan and mature decorin in patients and controls. In normal costal cartilage of different ages, the mature form of decorin was absent in a fetal sample whereas mature biglycan was weakly expressed, suggestive that mature biglycan may play a role in early costal cartilage development. Further studies are needed to determine the functional differences between the pro- and mature forms of biglycan and decorin both in age and disease

Geographical Analysis of Agro-Environmental Measures for Reduction of Chemical Inputs in Tuscany

The agro-environmental policies included in rural development plans are getting increasing importance in European Community strategies. These policies represent the meeting point between demand and supply of positive externalities. The difficulty of assessing real envi- ronmental efficiency is one of the elements characterizing agro-environmental measures. This difficulty is related to the identification of suitable parameters for evaluating farms according to their impact on the territory. This impact is mainly related both to chemical inputs and to the territorial characteristics of the farm. Different types of fertilizers, pesti- cides and herbicides are currently used in production processes; however, the analysis has focused only on nitrates, as they represent the most critical types of chemicals related to soil pollution. A case study is provided by analysis of agro-environmental measures in Tuscany for the reduction of nitrates in organic and integrated farms. Using spatial multicriteria analysis, integrated and organic farms were classified according to their geographical loca- tions and their release of nitrates into the soil. This classification permits the highlighting of farms that make the greatest economic efforts to reduce pollution and therefore it could determine environmental benefits. Considering that the trend of policy strategies is toward a reduction of monetary resources, the classification could help decision makers choose the right allocation of future resources

On the Response of an OST to a Point-like Heat Source

A new technique of superconducting cavity diagnostics has been introduced by D. Hartrill at Cornell University, Ithaca, USA. Oscillating Superleak Transducers (OST) detect the heat transferred from a cavity's quench point via "Second Sound" through the superfluid He bath, needed to cool the superconducting cavity. The observed response of an OST is a complex, but reproducible pattern of oscillations. A small helium evaporation cryostat was built which allows the investigation of the response of an OST in greater detail. The distance between a point-like electrical heater and the OST can be varied. The OST can be mounted either parallel or perpendicular to the plate, housing the heat source. If the artificial quench-point releases an amount of energy compatible to a real quench spot on a cavity's surface, the OST signal starts with a negative pulse, which is usually strong enough to allow automatic detection. Furthermore, the reflection of the Second Sound on the wall is observed. A reflection coefficient R = 0.39 +- 0.05 of the glass wall is measured. This excludes a strong influence of multiple reflections in the complex OST response. Fourier analyses show three main frequencies, found in all OST spectra. They can be interpreted as modes of an oscillating circular membrane.Comment: 10 pages, 16 figure