Search

Stochastic precipitation generators (SPGs) are often used to produce synthetic precipitation series for water resource management. Typically, an SPG assumes a stationary climate. We present an hourly precipitation generation algorithm for nonstationary conditions informed by the global climate model (GCM) forecasted average monthly temperature (AMT). The physical basis for precipitation formation is considered explicitly in the design of the algorithm using hourly pressure change events (PCE) to define the relationship between hourly precipitation and AMT. The algorithm consists of a multivariable Markov Chain and a moving window driven by time, temperature, and pressure change. We demonstrate the methodology by generating a 100‐year, continuous, synthetic hourly precipitation time series using GCM AMT projections for the Northeast United States. When compared with historical observations, the synthetic results suggest that future precipitation in this region will be more variable, with more frequent mild events and fewer but intensified extremes, especially in warm seasons. The synthetic time series suggests that there will be less precipitation in the summers, while winters will be wetter, consistent with other research on climate change projections for the Northeast United States. This SPG provides physically plausible weather ensembles for water resource studies involving climate change. Key Points: This article introduces a nonparametric stochastic process in generating synthetic precipitations for nonstationary climateThe basis of this algorithm is highly related to the physical mechanism of precipitation formation defined by pressure change events [ABSTRACT FROM AUTHOR]

Abstract: Mechanisms such as ice‐shelf hydrofracturing and ice‐cliff collapse may rapidly increase discharge from marine‐based ice sheets. Here, we link a probabilistic framework for sea‐level projections to a small ensemble of Antarctic ice‐sheet (AIS) simulations incorporating these physical processes to explore their influence on global‐mean sea‐level (GMSL) and relative sea‐level (RSL). We compare the new projections to past results using expert assessment and structured expert elicitation about AIS changes. Under high greenhouse gas emissions (Representative Concentration Pathway [RCP] 8.5), median projected 21st century GMSL rise increases from 79 to 146 cm. Without protective measures, revised median RSL projections would by 2100 submerge land currently home to 153 million people, an increase of 44 million. The use of a physical model, rather than simple parameterizations assuming constant acceleration of ice loss, increases forcing sensitivity: overlap between the central 90% of simulations for 2100 for RCP 8.5 (93–243 cm) and RCP 2.6 (26–98 cm) is minimal. By 2300, the gap between median GMSL estimates for RCP 8.5 and RCP 2.6 reaches >10 m, with median RSL projections for RCP 8.5 jeopardizing land now occupied by 950 million people (versus 167 million for RCP 2.6). The minimal correlation between the contribution of AIS to GMSL by 2050 and that in 2100 and beyond implies current sea‐level observations cannot exclude future extreme outcomes. The sensitivity of post‐2050 projections to deeply uncertain physics highlights the need for robust decision and adaptive management frameworks. [ABSTRACT FROM AUTHOR]

Aims Prostate cancer is the most frequently diagnosed male cancer and urinary incontinence represents a major consequence following surgery. Penile compression clamps (PCCs) which externally occlude the urethra may be used to manage the incontinence. Despite potential complication of PCCs, such as deformation-inflicted tissue damage, to date, there are no reported biomechanical criteria for design of PCCs, in terms of quantitative parameters for evaluating the safety-versus-efficacy of existing or future designs. Methods We developed a set of computational three-dimensional models of the penis, to which compression was applied using five generic PCC designs. The internal mechanical states of the soft tissues of the penis were then analysed using finite element simulations. Results Stresses in skin, fat, and tunica albuginea regularly exceeded 10 kPa (75 mmHg). Cuff-type and knurl-type PCCs pose the highest potential risks to tissue health with elevated tissue stresses around the entire penile perimeter (cuff) or urethral stress concentrations (knurl). The soft and contoured PCCs produced the lowest values of these mechanical parameters. Conclusions The present study identified design characteristics, including envelopment, adaptability, and durability which provide the safest mechanical conditions in the penis and thus minimize the risk of tissue damage while still managing incontinence. Such data should help to design a safer clamp. [ABSTRACT FROM AUTHOR]

ABSTRACT Articular cartilage with its inherently poor capacity for self-regeneration represents a primary target for tissue engineering strategies, with approaches focusing on the in vitro generation of neo-cartilage using chondrocyte-seeded 3D scaffolds subjected to mechanical conditioning. Although uniaxial compression regimens have significantly up-regulated proteoglycan synthesis, their effects on the synthesis of collagen have been modest. Articular cartilage is subjected to shear forces during joint motion. Accordingly, this study utilized an apparatus to apply biaxial loading to chondrocytes seeded within agarose constructs with endplates. The chondrocytes yielded a monotonic increase in proteoglycan synthesis both in free swelling culture up to day 8 and when the constructs were subjected to dynamic compression alone (15% amplitude at a frequency of 1 Hz for 48 h). However, when dynamic shear (10% amplitude at 1 Hz) was superimposed on dynamic compression, total collagen synthesis was also up-regulated, within 3 days of culture, without compromising proteoglycan synthesis. Histological analysis revealed marked collagen deposition around individual chondrocytes. A significant proportion (50%) of collagen was released into the culture medium, suggesting that it had only been partially synthesized in its mature state. The overall biosynthetic activity was enhanced more when the biaxial stimulation was applied in a continuous mode as opposed to intermittent loading. Results of the present study strongly suggest that proteoglycan and collagen synthesis may be triggered by uncoupled mechanosensitive cellular responses. The proposed in vitro model and the prescribed conditioning protocols demonstrated that a short pre-culture period is preferable to long free swelling culture condition as it enables a significantly higher up-regulation of collagen. Biotechnol. Bioeng. 2017;114: 1614-1625. © 2017 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Mechanisms conferring robustness against regulatory variants have been controversial. Previous studies suggested widespread buffering of RNA misexpression on protein levels during translation. We do not find evidence that translational buffering is common. Instead, we find extensive buffering at the level of RNA expression, exerted through negative feedback regulation acting in trans, which reduces the effect of regulatory variants on gene expression. Our approach is based on a novel experimental design in which allelic differential expression in a yeast hybrid strain is compared to allelic differential expression in a pool of its spores. Allelic differential expression in the hybrid is due to cis-regulatory differences only. Instead, in the pool of spores allelic differential expression is not only due to cis-regulatory differences but also due to local trans effects that include negative feedback. We found that buffering through such local trans regulation is widespread, typically compensating for about 15% of cis-regulatory effects on individual genes. Negative feedback is stronger not only for essential genes, indicating its functional relevance, but also for genes with low to middle levels of expression, for which tight regulation matters most. We suggest that negative feedback is one mechanism of Waddington's canalization, facilitating the accumulation of genetic variants that might give selective advantage in different environments. [ABSTRACT FROM AUTHOR]

The article focuses on the climate change indicators that can be monitored by the New York City Climate Change Adaptation Task Force in order to develop Flexible Adaptation Pathways for the city's critical infrastructure. It states that monitoring key indicators related to changes in the climate, climate impacts and adaptation activities can help in adaptation policies. It mentions that in the past, several methodologies have been developed for creating indicators to track climate changes.

The workbook "Climate Risk Information" (CRI) on climate trends and projections for New York City that relates to articles that appeared in the periodical "Annals of the New York Academy of Sciences" is presented.