Dose and life stage-dependent effects of dietary beta-carotene supplementation on the growth and development of the Booroolong frog

Carotenoids are known for their antioxidant capacity and are considered to play an important role in vertebrate growth and development. However, evidence for their beneficial effects remains limited, possibly because very few studies have tested for dose effects across different life stages. The present study investigated the effect of various doses of dietary beta-carotene supplements on the growth and development of larval and post-metamorphic Booroolong frogs (Litoria booroolongensis). Larval and post-metamorphic basal diets (containing 0.015 and 0.005 mg g−1 total carotenoids, respectively) were supplemented with beta-carotene at one of four concentrations: 0 mg g−1 , 0.1 mg g−1 , 1 mg g−1 and 10 mg g−1 . Each treatment included 72 replicate individuals, and individuals remained on the same diet treatment over both life stages (spanning 53 experimental weeks). Our results show that larvae receiving an intermediate (1 mg g−1 ) beta-carotene supplement dose grew faster than unsupplemented larvae (0 mg g−1 ), and metamorphosed earlier. After metamorphosis, there was no effect of the lowest supplement dose (0.1 mg g−1 ) on growth and development. However, juveniles fed the highest supplement dose (10 mg g−1 ) displayed significantly smaller body mass and lower body condition, compared to all other supplement doses, from 4-months through to sexual maturity (7-months). These findings indicate that beta-carotene supplementation has positive effects on growth and development, but only at intermediate doses, and only in the larval life stage. This knowledge may assist with amphibian conservation by expediting the rate that metamorphs can be generated in captive breeding programmes. More broadly, this is the first study to demonstrate both dose and life stagedependent effects of dietary beta-carotene supplementation on vertebrate growth and development

Timing of pubertal stages and breast cancer risk : the Breakthrough Generations Study

Introduction: Breast development and hormonal changes at puberty might affect breast cancer risk, but epidemiological analyses have focussed largely on age at menarche and not at other pubertal stages. Methods: We investigated associations between the timing of pubertal stages and breast cancer risk using data from a cohort study of 104,931 women (Breakthrough Generations Study, UK, 2003–2013). Pubertal variables were reported retrospectively at baseline. Breast cancer risk was analysed using Cox regression models with breast cancer diagnosis as the outcome of interest, attained age as the underlying time variable, and adjustment for potentially confounding variables. Results: During follow-up (mean = 4.1 years), 1094 breast cancers (including ductal carcinoma in situ) occurred. An increased breast cancer risk was associated with earlier thelarche (age when breast growth begins; HR [95% CI] = 1.23 [1.02, 1.48], 1 [referent] and 0.80 [0.69, 0.93] for ≤10, 11–12 and ≥13 years respectively), menarche (initiation of menses; 1.06 [0.93, 1.21], 1 [referent] and 0.78 [0.62, 0.99] for ≤12, 13–14 and ≥15 years), regular periods (0.99 [0.83, 1.18], 1 [referent] and 0.74 [0.59, 0.92] for ≤12, 13–14 and ≥15 years) and age reached adult height (1.25 [1.03, 1.52], 1 [referent] and 1.07 [0.87, 1.32] for ≤14, 15–16 and ≥17 years), and with increased time between thelarche and menarche (0.87 [0.65, 1.15], 1 [referent], 1.14 [0.96, 1.34] and 1.27 [1.04, 1.55] for <0, 0, 1 and ≥2 years), and shorter time between menarche and regular periods (1 [referent], 0.87 [0.73, 1.04] and 0.66 [0.50, 0.88] for 0, 1 and ≥2 years). These associations were generally similar when considered separately for premenopausal and postmenopausal breast cancer. Conclusions: Breast duct development may be a time of heightened susceptibility to risk of carcinogenesis, and greater attention needs to be given to the relation of breast cancer risk to the different stages of puberty

InterPack2003-35287 MULTI-SCALE OPTICAL DESIGN FOR GLOBAL CHIP-TO-CHIP OPTICAL INTERCONNECTIONS AND MISALIGNMENT TOLERANT PACKAGING

ABSTRACT As transistor densities on integrated circuits (ICs) continue to grow, off-chip bandwidth is becoming an ever-increasing performance-limiting bottleneck in systems. Electronic multichip module (MCM) and printed circuit board (PCB) packaging technology has not kept pace with the growth of inter-chip interconnection requirements. Recent advances in &quot;smart pixel&quot; technology offer the potential to use optical interconnects to overcome the inter-chip I/O bottleneck by linking dense arrays of Vertical Cavity Surface Emitting Lasers (VCSELs) and photodetectors. For optical interconnections to be relevant to real systems they must be able to be manufactured and packaged inexpensively and robustly. This paper discusses an optical design and packaging approach that utilizes multiple sizes (or scales) of optical elements to simplify the design of the optical interconnection and coupling while providing an enhanced degree of insensitivity to misalignments inherent in the packaging of these systems. The scales of the optical elements described are: the size of the IC (termed macrooptical), the size of the pitch of optical IO (termed microoptical), and sizes in between (termed mini-optical) which are smaller than the size of the IC but cover several optical IO. This paper describes the utility of elements of each of these scales and shows that through the combination of them simple robust systems can be constructed. Two case studies for applying this multi-scale optical design are examined. The first case study is a global chip-to-chip optical interconnection module (termed FAST-Net) that uses a macro lens array and mirror to effect the all-to-all optical interconnection pattern among an array of ICs on a single board. Micro-and mini-scale optical elements simplify the design of the macro-lens by performing corrections at scales where they are more effective. In this system over 11,000 optical links are implemented across a 5 inch multi-chip module with diffraction limited RMS spot sizes and registration errors less than 5 microns. The second case study analyzes designs for board-to-board optical interconnections with throw-distances ranging from 1 millimeter to several centimeters. In this case micro-and miniscale optical interconnections provide insensitivity to misalignments. The results show the feasibility of an optical coupler that can tolerate the typical packaging misalignments of 5 to 10 mil without placing rigid constraints on the angular sensitivity of the modules. The multi-scale optical interconnection and coupling concept is shown to provide an approach to simplifying design and packaging -and therefore the costs -associated with implementing optical interconnection systems

Survival-Time Distribution for Inelastic Collapse

In a recent publication [PRL {\bf 81}, 1142 (1998)] it was argued that a randomly forced particle which collides inelastically with a boundary can undergo inelastic collapse and come to rest in a finite time. Here we discuss the survival probability for the inelastic collapse transition. It is found that the collapse-time distribution behaves asymptotically as a power-law in time, and that the exponent governing this decay is non-universal. An approximate calculation of the collapse-time exponent confirms this behaviour and shows how inelastic collapse can be viewed as a generalised persistence phenomenon.Comment: 4 pages, RevTe

Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation. Volume 4: System models and data analysis

In this volume, volume 4 (of five volumes), the discussion is focussed on the system models and related data references and has the following subsections: space shuttle main engine, integrated solid rocket booster, orbiter auxiliary power units/hydraulics, and electrical power system

Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation, volume 1

This document is the Executive Summary of a technical report on a probabilistic risk assessment (PRA) of the Space Shuttle vehicle performed under the sponsorship of the Office of Space Flight of the US National Aeronautics and Space Administration. It briefly summarizes the methodology and results of the Shuttle PRA. The primary objective of this project was to support management and engineering decision-making with respect to the Shuttle program by producing (1) a quantitative probabilistic risk model of the Space Shuttle during flight, (2) a quantitative assessment of in-flight safety risk, (3) an identification and prioritization of the design and operations that principally contribute to in-flight safety risk, and (4) a mechanism for risk-based evaluation proposed modifications to the Shuttle System. Secondary objectives were to provide a vehicle for introducing and transferring PRA technology to the NASA community, and to demonstrate the value of PRA by applying it beneficially to a real program of great international importance

Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation. Volume 5: Auxiliary shuttle risk analyses

Volume 5 is Appendix C, Auxiliary Shuttle Risk Analyses, and contains the following reports: Probabilistic Risk Assessment of Space Shuttle Phase 1 - Space Shuttle Catastrophic Failure Frequency Final Report; Risk Analysis Applied to the Space Shuttle Main Engine - Demonstration Project for the Main Combustion Chamber Risk Assessment; An Investigation of the Risk Implications of Space Shuttle Solid Rocket Booster Chamber Pressure Excursions; Safety of the Thermal Protection System of the Space Shuttle Orbiter - Quantitative Analysis and Organizational Factors; Space Shuttle Main Propulsion Pressurization System Probabilistic Risk Assessment, Final Report; and Space Shuttle Probabilistic Risk Assessment Proof-of-Concept Study - Auxiliary Power Unit and Hydraulic Power Unit Analysis Report

Probabilistic risk assessment of the Space Shuttle. Phase 3: A study of the potential of losing the vehicle during nominal operation. Volume 2: Integrated loss of vehicle model

The application of the probabilistic risk assessment methodology to a Space Shuttle environment, particularly to the potential of losing the Shuttle during nominal operation is addressed. The different related concerns are identified and combined to determine overall program risks. A fault tree model is used to allocate system probabilities to the subsystem level. The loss of the vehicle due to failure to contain energetic gas and debris, to maintain proper propulsion and configuration is analyzed, along with the loss due to Orbiter, external tank failure, and landing failure or error