Numerical modelling of multiple standing column wells for heating and cooling buildings

A model for simulating clusters of standing column wells (SCWs) for use in geothermal heating and cooling systems is described in this paper. The model is three-dimensional, dynamic and solves the governing equations using a finite volume discretisation scheme with a fully implicit algorithm. The slower-acting field equations are solved using a wider time interval than that used for the faster-acting well equations and the two sets of equations are coupled through the field equation source terms. A groundwater bleed feature is incorporated. The model is applied to two evaluative test cases the first of which involves heating only and the second, heating and cooling. Results of the applications suggest that SCWs can deliver substantially higher rates of heat transfer than conventional closed loop borehole heat exchanger arrays especially when groundwater bleed is operational. An important practical consequence of this is that far less geotechnical drilling is needed when using SCWs than is the case with closed loop arrays

Letter from Sara A. Underwood, Chicago, Illinois, to Anne Whitney, 1893 October 18

https://repository.wellesley.edu/whitney_correspondence/2912/thumbnail.jp

Letter from Sara A. Underwood, Chicago, Illinois, to Anne Whitney, 1893 October 29

https://repository.wellesley.edu/whitney_correspondence/2913/thumbnail.jp

Tool life comparison between servo and pneumatic ultrasonic welders for cutting polylactic acid film

Polylactic acid (PLA) is a biobased plastic that is the polymerization product of lactic acid which is produced by fermentation of starches derived from renewable feedstocks. PLA is used for many commercial applications such as medical implants, food packaging, and disposable tableware. In many applications, such as packaging, the PLA film needs to be cut to produce the final product. The purpose of this research is to determine the effect of tool wear during ultrasonic cutting of PLA films. In more, this study compares tool wear between pneumatic and servo ultrasonic cutting systems. The study also investigated the effect of different amplitudes (using boosters with gains of; 1:1, 1:1.5, and 1:2) on tool life for servo and pneumatic systems. There were significant differences in performance between the servo and pneumatic systems for the different amplitudes. The pneumatic system had consistently higher wear compared to the servo system for all the different amplitudes. It was believed that this was the result of cutting tool and horn contact was reduced for the servo driven system. In contrast, the pneumatic driven system, required cutting tool and horn contact to terminate the cutting cycle, that resulted in tool wear. In addition, it was found that high amplitudes, generally reduced tool wear. While this observation may initially be counter intuitive, it is believed that this was the result of faster cutting rates, that reduced the number of ultrasonic cycles (20 kHz) required to cut the films, reducing the tool wear

Biología reproductiva del pepino de mar Holothuria sanctori (Echinodermata: Holothuroidea)

The reproductive biology of the sea cucumber Holothuria sanctori was studied over 24 months (February 2009 to January 2011) at Gran Canaria through the gonad index and a combination of macro- and microscopic analysis of the gonads. Holothuria sanctori showed a 1:1 sex ratio and a seasonal reproductive cycle with a summer spawning: the mean gonad index showed a maximum (3.99±0.02) in summer (June-July) and a minimum (0.05±0.04) between late autumn (November) and early spring (March). Females had significantly wider gonad tubules than males. First maturity occurred at a size of 201 to 210 mm, a gutted body weight of 101 to 110 g and a total weight of 176 to 200 g. Holothuria sanctori shows a typical temperate species reproduction pattern. These results could be useful for managing current extractions of H. sanctori in the Mediterranean and in case a specific fishery is started in the eastern Atlantic region.Se estudió la biología reproductiva del pepino de mar Holothuria sanctori durante 24 meses (Febrero de 2009 a Enero de 2010) en la isla de Gran Canaria, mediante el índice gonadal y una combinación de análisis macro y microscópicos de sus gónadas. Holothuria sanctori presentó una relación de sexos de 1:1 y un solo ciclo reproductivo anual con desove en los meses estivales: el índice gonadal medio presentó un máximo (3.99±0.02) en verano (Junio-Julio) y un mínimo (0.05±0.04) entre finales de otoño (Noviembre) y primeros de primavera (Marzo). Las hembras presentaron túbulos gonadales significativamente más anchos que los de los machos. La primera madurez tuvo lugar con una talla de 201-210 mm, un peso eviscerado de 101-110 g y un peso total de 176-200 g. Holothuria sanctori presenta un patrón de reproducción típico en especies de zonas templadas. Estos resultados pueden ser útiles para gestionar las capturas actuales de H. sanctori en el Mediterráneo y en el caso de que una pesquería específica empezase en la región oriental del Atlántico

Antioxidants can inhibit basal autophagy and enhance neurodegeneration in models of polyglutamine disease.

Many neurodegenerative diseases exhibit protein accumulation and increased oxidative stress. Therapeutic strategies include clearing aggregate-prone proteins by enhancing autophagy or decreasing oxidative stress with antioxidants. Many autophagy-inducing stimuli increase reactive oxygen species (ROS), raising concerns that the benefits of autophagy up-regulation may be counterbalanced by ROS toxicity. Here we show that not all autophagy inducers significantly increase ROS. However, many antioxidants inhibit both basal and induced autophagy. By blocking autophagy, antioxidant drugs can increase the levels of aggregate-prone proteins associated with neurodegenerative disease. In fly and zebrafish models of Huntington's disease, antioxidants exacerbate the disease phenotype and abrogate the rescue seen with autophagy-inducing agents. Thus, the potential benefits in neurodegenerative diseases of some classes of antioxidants may be compromised by their autophagy-blocking properties

The "ram effect": new insights into neural modulation of the gonadotropic axis by male odors and socio-sexual interactions

Reproduction in mammals is controlled by the hypothalamo-pituitary-gonadal (HPG) axis under the influence of external and internal factors such as photoperiod, stress, nutrition, and social interactions. Sheep are seasonal breeders and stop mating when day length is increasing (anestrus). However, interactions with a sexually active ram during this period can override the steroid negative feedback responsible for the anoestrus state, stimulate LH secretion and eventually reinstate cyclicity. This is known as the ram effect and research into the mechanisms underlying it is shedding new light on HPG axis regulation. The first step in the ram effect is increased LH pulsatile secretion in anestrus ewes exposed to a sexually active male or only to its fleece, the latter finding indicating a pheromone-like effect. Estradiol secretion increases in all ewes and this eventually induces a LH surge and ovulation, just as during the breeding season. An exception is a minority of ewes that exhibit a precocious LH surge (within 4h) with no prior increase in estradiol. The main olfactory system and the cortical nucleus of the amygdala are critical brain structures in mediating the ram effect since it is blocked by their inactivation. Sexual experience is also important since activation (increased c-fos expression) in these and other regions is greatly reduced in sexually naïve ewes. In adult ewes kisspeptin neurons in both arcuate and preoptic regions and some preoptic GnRH neurons are activated 2h after exposure to a ram. Exposure to rams also activates noradrenergic neurons in the locus coeruleus and A1 nucleus and increased noradrenalin release occurs in the posterior preoptic area. Pharmacological modulation of this system modifies LH secretion in response to the male or his odor. Together these results show that the ram effect can be a fruitful model to promote both a better understanding of the neural and hormonal regulation of the HPG axis in general and also the spe

Complex inhibitory effects of nitric oxide on autophagy.

Autophagy, a major degradation process for long-lived and aggregate-prone proteins, affects various human processes, such as development, immunity, cancer, and neurodegeneration. Several autophagy regulators have been identified in recent years. Here we show that nitric oxide (NO), a potent cellular messenger, inhibits autophagosome synthesis via a number of mechanisms. NO impairs autophagy by inhibiting the activity of S-nitrosylation substrates, JNK1 and IKKβ. Inhibition of JNK1 by NO reduces Bcl-2 phosphorylation and increases the Bcl-2-Beclin 1 interaction, thereby disrupting hVps34/Beclin 1 complex formation. Additionally, NO inhibits IKKβ and reduces AMPK phosphorylation, leading to mTORC1 activation via TSC2. Overexpression of nNOS, iNOS, or eNOS impairs autophagosome formation primarily via the JNK1-Bcl-2 pathway. Conversely, NOS inhibition enhances the clearance of autophagic substrates and reduces neurodegeneration in models of Huntington's disease. Our data suggest that nitrosative stress-mediated protein aggregation in neurodegenerative diseases may be, in part, due to autophagy inhibition

CLIMB-COVID: continuous integration supporting decentralised sequencing for SARS-CoV-2 genomic surveillance.

Funder: Wellcome TrustIn response to the ongoing SARS-CoV-2 pandemic in the UK, the COVID-19 Genomics UK (COG-UK) consortium was formed to rapidly sequence SARS-CoV-2 genomes as part of a national-scale genomic surveillance strategy. The network consists of universities, academic institutes, regional sequencing centres and the four UK Public Health Agencies. We describe the development and deployment of CLIMB-COVID, an encompassing digital infrastructure to address the challenge of collecting and integrating both genomic sequencing data and sample-associated metadata produced across the COG-UK network