Effects of Root Zone Temperature on Growth and Photosynthetic Parameters of Grafted Cucumber

Taking Cucurbita maxima and Cucurbita moschata as root stocks,and‘Jinyou No 3'cucumber as scion,the effects of different root zone temperature conditions optimal temperature(CK)(18-20℃),suboptimal temperature(13-15℃)and low temperature(8-10℃)on the growth and photosynthesis indexes were studied.The results showed that,compared with optimal temperature(CK),suboptimal temperature and low temperature produced a significant inhibition of growth on cucumbers.The plant height,stem diameter,leaf area,number of leaves and dry weight of aboveground part were all reduced,dry weight of underground part and root shoot ratio all increased,while the inhibition was more significant at low temperature.Low and suboptimal temperature conditions also reduced SPAD value,net photosynthetic rate,transpiration rate,intercellular CO_(2) concentration and stomatal conductance of the grafted cucumber.And there were differences between different grafted seedlings,and seedlings with‘black seeds'as stock performed better than those with‘white seeds'as stock at low temperature.

TcPO_(2)changes are more pronounced than SpO_(2)changes during simulated altitude changes in a hypobaric oxygen chamber:a nonrandomized controlled trial

Background:Hypoxia is a significant risk factor of hypertension.However,no studies have used transcutaneous tissue partial pressure of oxygen(TcPO_(2))and partial pressure of carbon dioxide(TcPCO_(2))monitors to measure the respective partial pressures in healthy individuals.Oxygen saturation(SpO_(2))is often used for traditional monitoring of vital signs.This study investigated the changes in TcPO_(2)and SpO_(2)values during rapid changes in altitude.The trial was registered at ClinicalTrials.gov(registration no.NCT06076057).Methods:Healthy adult volunteers were instructed to sit vertically in a hypobaric oxygen chamber,which ascended from 0 m to 2500 m at a uniform speed within 10 min.The Danish Radiometer TCM4 was used to measure TcPO_(2)and TcPCO_(2)with the ventral side of the upper arm as the measurement site.The Shenzhen Kerokan P0D-1 W pulse oximeter was used to measure heart rate and SpO_(2),with values recorded once every 500 m.Results:Altogether,49 healthy volunteers were recruited between March 2023 and August 2023.With increasing altitude,TcPO_(2)and SpO_(2)decreased significantly(P<0.01).During the ascent from 0 m,TcPO_(2)began to change statistically at 500 m(P<0.05),whereas SpO_(2)began to change statistically at 1000 m(P<0.05).At the same altitude,the difference in TcPO_(2)was greater than the difference in SpO_(2).At 1000 m,there were statistically significant changes in TcPO_(2)and SpO_(2)(P<0.001).At altitudes>500 m,statistical significance was identified between TcPO_(2)in both sexes(P<0.05).Statistical significance in TcPCO_(2)and heart rate was observed at the different elevations(P<0.05).Conclusion:In acutely changing low-pressure hypoxic environments,TcPO_(2)changed more dramatically than SpO_(2).

Experimental investigation of characteristics of instability evolution in a centrifugal compressor

The stable range of operation for the centrifugal compressor significantly influences the dynamic,economic,and environment-friendly characteristics of power systems.A deep understand-ing of the characteristics of instability evolution is necessary to improve the compressor stability.A centrifugal compressor equipped with a vaneless diffuser is experimentally investigated using high-response static-pressure measurements.The results obtained indicate that three typical rotational-speed ranges exist based on the different instability evolution characteristics,which reveals the var-ious impeller–diffuser matching behaviors over the entire speed range.At low-speed ranges((40%–75%)N_(max),N_(max)is the maximum rotational speed),the compressor exhibits stable,Rotating Insta-bility(RI),impeller stall(diffuser stall),and surge modes.The impeller stall mode is induced by RI and propagates downstream,resulting in the diffuser stall and compressor surge modes.In the medium-speed range((75%–85%)N_(max)),the compressor exhibits stable,diffuser stall,RI,and surge modes.In the high-speed range((85%–100%)N_(max)),the compressor exhibits stable,diffuser stall,and surge modes.The dominant instability position is shifted from the impeller to the diffuser as the rotational speed increases.Both the impeller and diffuser stall present an irregular sawtooth static-pressure wave and exhibit broadband frequency spectrum patterns.

Degradability of biodegradable plastic films and its mulching effects on soil temperature and maize yield in northeastern China

Plastic film is an important resource in agricultural production,but it takes hundreds of years to degrade completely in natural environment.The large-scale use of plastic film will inevitably lead to serious environmental pollution.One way to solve the problem is to develop a substitutable mulching film,such as a biodegradable film that can ultimately be decomposed to water,carbon dioxide,and soil organic matter by micro-organisms.In this study,a 2-year experiment was conducted to determine the degradation properties of a biodegradable plastic film,including degradation rate,surface microstructure,tensile strength and elongation at break,and the effects of different mulching treatments on soil temperature and maize yield.The mulching experiment was conducted with three different biodegradable plastic films with different degradation rates,using a common plastic film and a non-mulched treatment as control.With the addition of the additives for degradation in the biodegradable plastic films,the degradation rates increased significantly,which were 7.2%-17.8%in 2017 and 18.1%-35.2%in 2018 after maize harvesting.However,the degradation occurred mainly on the ridge side.The decrease in tensile strength and elongation was proportional to the degradation rate of the degradable film.The SEM results indicated that the surface microstructures of the biodegradable films were loose and heterogeneous after maize harvesting.Biodegradable plastic film mulching increased the soil temperature at soil depths of 5 cm,15 cm,and 25 cm,over the maize’s entire growth period,by 3.1℃-3.2℃ in 2017 and 1.2℃-2.1℃ in 2018 compared with the non-mulched treatment.The biodegradable plastic film increased the maize yield by 10.4%-14.3%in 2017 and 11.6%-24.7%in 2018.The soil temperature and maize yield increases were statistically significant;however,with respect to maize qualities,there were no statistically significant increases among the five treatments.This study shows that biodegradable plastic film can be used as a substitute for common plastic film.However,the ingredients in biodegradable plastic films should be improved further to ensure that they can be degraded completely after crop harvest.

Separating overlapping bat calls with a bi-directional long short-term memory network

Acquiring clear acoustic signals is critical for the analysis of animal vocalizations.Bioacoustics studies commonly face the problem of overlapping signals,which can impede the structural identification of vocal units,but there is currently no satisfactory solution.This study presents a bi-directional long short-term memory network to separate overlapping echolocation-communication calls of 6 different bat species and reconstruct waveforms.The separation quality was evaluated using 7 temporal-spectrum parameters.All the echolocation pulses and syllables of communication calls in the overlapping signals were separated and parameter comparisons showed no significant difference and negligible deviation between the extracted and original calls.Clustering analysis was conducted with separated echolocation calls from each bat species to provide an example of practical application of the separated and reconstructed calls.The result of clustering analysis showed high corrected rand index(82.79%),suggesting the reconstructed waveforms could be reliably used for species classification.These results demonstrate a convenient and automated approach for separating overlapping calls.The study extends the application of deep neural networks to separate overlapping animal sounds.