Take one

This item contains two issues of the Take One newsletter: January 15, and 29, 1988Take One was published every two weeks and focused on short news items and announcements "for the people of University Hospital.

Low GWP Refrigerant and Partial Miscible Lubricant

Lubricant selection is based on several lubricant properties to satisfied compressor and system reliability, longevity and energy efficiency performances. The use of non-miscible or low soluble lubricant can bring some technical advantage for the compressor and the system. This paper presents investigations results on low GWP refrigerant alternatives for light commercial and commercial applications. The work also targets the reduction refrigerant charge associated with the compressor characteristics

Evaluation of methods to decrease the discharge temperature of R32 scroll compressor

Recently, R32 has been considered as an important alternative in application of small to middle capacity air conditioner by many countries due to its advantages such as low global warming potential (GWP), favorable thermal properties, less refrigerant charge and low cost. However, the much increased discharge temperature of R32 compressor, as compared with the R22, becomes the main barrier affecting the wide and quick alternation. Refrigerant injection has proven to be effective in decreasing discharge temperature. In this work, three kinds of refrigerant injection technology used to decrease the discharge temperature of R32 scroll compressor are discussed, namely, two-phase suction, liquid injection and two-phase/gas injection. The detailed scroll compressor model proposed in previous work is modified and validated by experimental data of R32 scroll compressor. The potentials in decreasing discharge temperature of the three methods are investigated. The detailed performance comparisons are presented. The results indicate that the two-phase/gas injection achieves the best performance with the enhancement of cooling capacity by 14.2% and increase in COP by 8.1%

Timing landslide and flash flood events from SAR satellite: a regionally applicable methodology illustrated in African cloud-covered tropical environments

Landslides and flash floods are geomorphic hazards (GHs) that often co-occur and interact. They generally occur very quickly, leading to catastrophic socioeconomic impacts. Understanding the temporal patterns of occurrence of GH events is essential for hazard assessment, early warning, and disaster risk reduction strategies. However, temporal information is often poorly constrained, especially in frequently cloud-covered tropical regions, where optical-based satellite data are insufficient. Here we present a regionally applicable methodology to accurately estimate GH event timing that requires no prior knowledge of the GH event timing, using synthetic aperture radar (SAR) remote sensing. SAR can penetrate through clouds and therefore provides an ideal tool for constraining GH event timing. We use the open-access Copernicus Sentinel-1 (S1) SAR satellite that provides global coverage, high spatial resolution (∼10–15 m), and a high repeat time (6–12 d) from 2016 to 2020. We investigate the amplitude, detrended amplitude, spatial amplitude correlation, coherence, and detrended coherence time series in their suitability to constrain GH event timing. We apply the methodology on four recent large GH events located in Uganda, Rwanda, Burundi, and the Democratic Republic of the Congo (DRC) containing a total of about 2500 manually mapped landslides and flash flood features located in several contrasting landscape types. The amplitude and detrended amplitude time series in our methodology do not prove to be effective in accurate GH event timing estimation, with estimated timing accuracies ranging from a 13 to 1000 d difference. A clear increase in accuracy is obtained from spatial amplitude correlation (SAC) with estimated timing accuracies ranging from a 1 to 85 d difference. However, the most accurate results are achieved with coherence and detrended coherence with estimated timing accuracies ranging from a 1 to 47 d difference. The amplitude time series reflect the influence of seasonal dynamics, which cause the timing estimations to be further away from the actual GH event occurrence compared to the other data products. Timing estimations are generally closer to the actual GH event occurrence for GH events within homogenous densely vegetated landscape and further for GH events within complex cultivated heterogenous landscapes. We believe that the complexity of the different contrasting landscapes we study is an added value for the transferability of the methodology, and together with the open-access and global coverage of S1 data it has the potential to be widely applicable.</p

Evolution of the respiratory function of professional divers over 15 years

Background: The study was aimed at assessing changes in respiratory function after 15 years of profes- sional diving, among scientific divers. Materials and methods: A retrospective study was performed on divers who underwent an initial visit and a visit 15 years later at the same medical centre, among divers who had a scientific activity (monitoring the coastline, fauna and flora). Pulmonary function tests were performed in the same laboratory with the same operating standards and using a Jaeger MasterBody plethysmograph. Each subject acted as his or her own control. The data were analysed by Student’s t-test and Spearman’s correlation coefficient.  Results: Twenty-six divers were included. Changes over 15 years included: a decrease in the forced expired volume in 1 second/functional vital capacity (FEV1/FVC) ratio (–6 for absolute value, p &lt; 0.01; and –5% for theoretical value, p = 0.02); a decrease in forced expiratory flow (FEF)25% (–1.1 for absolute value, p &lt; 0.01; and –21% for theoretical value, p &lt; 0.01); a decrease in transfer factor for carbon monoxide (TLCO) (–0.7 for absolute value, p = 0.04); and an increase in vital capacity (VC) (+8% for theoretical value, p = 0.03). A significant correlation was found between the consumption of tobacco in packs per year (PY) and the variations in VC (r = 0.89; p &lt; 0.01) and the variations in the theoretical FEV1 (r = 0.76; p = 0.03). There was a significant relationship between the number of dives and the variations in the percentage of the theoretical FEV1/FVC ratio (r = –0.42; p = 0.04). The same relationship was found for the average of dive duration (r = –0.59; p &lt; 0.01)  Conclusions: With increasing length of diving activities service, the pulmonary function displays a trend toward both a decrease in TLCO and a decrease in FEF25%.

Phosphorus Versus Arsenic: Role of the Photodiode Doping Element in CMOS Image Sensor Radiation-Induced Dark Current and Random Telegraph Signal

This work the role of the phosphorus doping element in the radiation-induced dark current in a CMOS image sensor (CIS) photodiode. The neutron and proton irradiations on shallow arsenic-based photodiode CISs and deep phosphorus-based photodiodes CISs have been performed. The results highlight the applicability of the same dark current increase and random telegraph signal (RTS) models. Already verified on other photodiode structures, these results further extend the universality of these analytic tools. Moreover, it emphasizes that the phosphorus element does not play a significant role either in the radiation-induced dark current increase or in the dark current RTS. The results on RTS after annealing reveal the same recovery dynamic than those already observed in irradiated image sensors, suggesting that the phosphorus element does not play a significant role after annealing. Therefore, this work is a piece of experimental evidence supporting the idea that RTS induced by displacement damage is principally due to defect clusters mainly constituted of intrinsic silicon defects such as clusters of vacancies and interstitials

Modulation of the vertical particle transfer efficiency in the oxygen minimum zone off Peru

The fate of the organic matter (OM) produced by marine life controls the major biogeochemical cycles of the Earth's system. The OM produced through photosynthesis is either preserved, exported towards sediments or degraded through remineralisation in the water column. The productive eastern boundary upwelling systems (EBUSs) associated with oxygen minimum zones (OMZs) would be expected to foster OM preservation due to low O2 conditions. But their intense and diverse microbial activity should enhance OM degradation. To investigate this contradiction, sediment traps were deployed near the oxycline and in the OMZ core on an instrumented moored line off Peru. Data provided high-temporal-resolution O2 series characterising two seasonal steady states at the upper trap: suboxic ([O2]  50%) and remineralisation (intermediate Teff 20  50%) has been reported in summer and winter associated with extreme limitation in O2 concentrations or OM quantity for OM degradation. However, higher levels of O2 or OM, or less refractory OM, at the oxycline, even in a co-limitation context, can decrease the OMZ transfer efficiency to below 50%. This is especially true in summer during intraseasonal wind-driven oxygenation events. In late winter and early spring, high oxygenation conditions together with high fluxes of sinking particles trigger a shutdown of the OMZ transfer (Teff < 6%). Transfer efficiency of chemical elements composing the majority of the flux (nitrogen, phosphorus, silica, calcium carbonate) follows the same trend as for carbon, with the lowest transfer level being in late winter and early spring. Regarding particulate isotopes, vertical transfer of δ15N suggests a complex pattern of 15N impoverishment or enrichment according to Teff modulation. This sensitivity of OM to O2 fluctuations and particle concentration calls for further investigation into OM and O2-driven remineralisation processes. This should include consideration of the intermittent behaviour of OMZ towards OM demonstrated in past studies and climate projections

The AUXIN BINDING PROTEIN 1 Is Required for Differential Auxin Responses Mediating Root Growth

Background In plants, the phytohormone auxin is a crucial regulator sustaining growth and development. At the cellular level, auxin is interpreted differentially in a tissue- and dose-dependent manner. Mechanisms of auxin signalling are partially unknown and the contribution of the AUXIN BINDING PROTEIN 1 (ABP1) as an auxin receptor is still a matter of debate. Methodology/Principal Findings Here we took advantage of the present knowledge of the root biological system to demonstrate that ABP1 is required for auxin response. The use of conditional ABP1 defective plants reveals that the protein is essential for maintenance of the root meristem and acts at least on the D-type CYCLIN/RETINOBLASTOMA pathway to control entry into the cell cycle. ABP1 affects PLETHORA gradients and confers auxin sensitivity to root cells thus defining the competence of the cells to be maintained within the meristem or to elongate. ABP1 is also implicated in the regulation of gene expression in response to auxin. Conclusions/Significance Our data support that ABP1 is a key regulator for root growth and is required for auxin-mediated responses. Differential effects of ABP1 on various auxin responses support a model in which ABP1 is the major regulator for auxin action on the cell cycle and regulates auxin-mediated gene expression and cell elongation in addition to the already well known TIR1-mediated ubiquitination pathway

Race and the Legacy of the First World War in French Anti-Colonial Politics of the 1920s

There has been relatively little historical research on the small number of African veterans who stayed on in France after the First World War and became militants in the radical anti-colonial movements created in the 1920s. From his entry onto the political stage in late 1924 until his early death three years later, the most celebrated and feared of these anti-colonial militants was Lamine Senghor, a decorated war veteran from Senegal. This chapter will chart Senghor’s brief career as an activist, focusing primarily on the ways in which he projected his identity as a veteran in his speeches and writings, as well as exploring, more generally, how France’s “blood debt” to its colonial subjects became a key theme of anti-colonial discourse in the interwar period