The accuracy of extracting projected pig area is critical to the accuracy of the weight measurement of pigs by machine vision.The capability of both the conventional and the edge detection methods for extracting pig a...The accuracy of extracting projected pig area is critical to the accuracy of the weight measurement of pigs by machine vision.The capability of both the conventional and the edge detection methods for extracting pig area was examined using the images of 47 pigs of different weights.Relationship between the threshold value and the extracted area was numerically analyzed for both methods.It was found that the accuracy of the conventional method depended heavily on the threshold value,while choice of threshold value in the edge detection approach had no influence on the extracted area over a wide range.In normal lighting conditions,both methods yielded comparable values of predicted weight;however,under variable light intensities,the edge detection method was superior to the conventional method,because the former was proven to be independent of light intensities.This makes edge detection an ideal method for area extraction during the walk-through weighing process where pigs are allowed to move around.展开更多
A development of an acquisition of the characteristic of a solar panel by automatic load variation system is put into play and coupled to an instrumentation chain for taking account of temperature. A programmed digita...A development of an acquisition of the characteristic of a solar panel by automatic load variation system is put into play and coupled to an instrumentation chain for taking account of temperature. A programmed digital microprocessor control enables this automation. Design and implementation of a device for automation of variations of the resistive load are powered by solar panel. It is provided by a PIC 16F877A running a computer program that we have developed on the basis of an algorithm according to the operation that we have set. By varying automatically the resistive load, we were able to automatically acquire the characteristic I-V and temperature of the solar panel. With automatic combinations of the 10 resistors, we have obtained 1024 measures of the characteristic curve of the solar cell which has a good accuracy. The change in load and temperature measurement allows us to have the characteristic curves parameterized by temperature.展开更多
In static regime with polychromatic illumination, using the expression of the solar cell capacitance to determine the silicon solar cell capacitance C<sub>0</sub>(T) in short-circuit, is the purpose of thi...In static regime with polychromatic illumination, using the expression of the solar cell capacitance to determine the silicon solar cell capacitance C<sub>0</sub>(T) in short-circuit, is the purpose of this article. The expression of the excess minority carries density δ(x) from the continuity equation. The expression of δ(x) is used to determine the photovoltage expression. The capacitance efficiency dependence on X<sub>cc</sub>(T) is studied. X<sub>cc</sub>(T) is the abscissa of the maximum of δ(x).展开更多
This study assesses the chemical quality of water resources in the Lower Senegal River valley, based on 35 samples collected in November 2022. Major ion concentrations in surface water and groundwater were analyzed us...This study assesses the chemical quality of water resources in the Lower Senegal River valley, based on 35 samples collected in November 2022. Major ion concentrations in surface water and groundwater were analyzed using classical geochemical interpretation diagrams (Piper, GIBBS, etc.) and multivariate geostatistical analyses, including hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results revealed three types of facies: Ca-Mg-HCO3-type facies, characteristic of poorly mineralized waters such as surface waters and groundwater from dune formations and the alluvial plain close to the hydraulic axis;Na-Cl type facies associated with well waters located in the alluvial plain that tap Inchirian or Nouakchottian shallow reservoirs and Maastrichtian deep borehole waters;and mixed Ca-Cl and Na-HCO3 type facies observed in certain floodplain and dune reservoirs. The results showed a strong correlation between sodium, chlorides, bromides, and electrical conductivity, indicating a significant contribution of these ions to groundwater mineralization. The various sources of water mineralization include mixing processes between surface water or rainwater, or calcite or dolomite dissolution processes (for weakly mineralized waters), basic exchanges or inverse basic exchanges between the aquifer and the water table (for moderately mineralized waters), and evaporation processes, halite dissolution, and paleosalinity during periods of marine transgression and regression (for highly mineralized waters). The study also highlighted the high vulnerability of the alluvial aquifer to pollution from intensive irrigated agriculture, as significant quantities of sulfates and nitrates were measured in some samples. These results also highlight the importance of water quality management in the Lower Senegal Valley, particularly as concerns the protection of the alluvial aquifer against pollution from irrigated agriculture.展开更多
West Africa was hit by an unprecedented drought in the 1970’s and 1980’s years, with dramatic consequences for surface and groundwater resources. In the context of climate change, there are many studies for the pred...West Africa was hit by an unprecedented drought in the 1970’s and 1980’s years, with dramatic consequences for surface and groundwater resources. In the context of climate change, there are many studies for the prediction of the increase in the occurrence of these droughts. To predict this situation in the Senegalese region, it is necessary to use regional climate models, which carrying out the study. This work deals with the interest to examine the capacity of the RCMs (regional climate models) in order to reproduce the deficit on the 1970’s year rainfall in Senegal. In this work, we used daily precipitation data from five (5) regional climate models to characterize the droughts in Senegal by using the SPI (Standardized Precipitation Index) on different time scales (3, 6, 12 and 24 months). For this purpose, the index was calculated over two distinct periods: 1951-1969 and 1970-1990. The results show that the period 1970-1990 was drier than the period 1951-1969. For the zonal average, the results show that the North of Senegal was more affected by this deficit rainfall than the South part. The analysis of the interannual variability of rainfall for some stations in Senegal shows that the drought did not start at the same time throughout the zone.展开更多
Introduction: Postpartum depression is the most common psychiatric disorder affecting women in the perinatal period. According to the WHO, it affects 10% - 15% of women who have just given birth. In Africa, and partic...Introduction: Postpartum depression is the most common psychiatric disorder affecting women in the perinatal period. According to the WHO, it affects 10% - 15% of women who have just given birth. In Africa, and particularly in Senegal, epidemiological studies focusing exclusively on postpartum depression are rare or non-existent. For this reason, we conducted this screening study on postpartum depression to assess the socio-demographic characteristics and associated factors. Methods: This was a prospective cross- sectional study with descriptive and analytical aims. It was carried out in the twelve Dakar referral health centres during the period August 2021 to June 2022. Results: At the end of our survey we had recruited one hundred and twenty-two (122) participants with a PPD prevalence rate of 25.41%. The most common age group was 24 - 29 years. 40% of the participants were of Fulani ethnicity, followed by Wolof. Married women made up 93% of the sample. The school enrolment rate was 89%. Most participants were not in paid employment. Domestic violence was present in 14% of couples. 28% of mothers reported experiencing a stressful life event during their pregnancy. 22% of the women had a chronic medical condition, of which 55% had high blood pressure. 1% of the women reported a personal psychiatric history and 5% a family psychiatric history. Most women had between two and four healthy living children. The pregnancy was unwanted in 17% of cases and 12% of participants had a complication. 6% were dissatisfied with the quality of their antenatal care. The caesarean section rate was 18%. In terms of associated factors, eight factors were identified in a bivariate analysis: single marital status, lack of support from partner, domestic violence, conflict with in-laws, and the occurrence of a stressful life event during pregnancy, the presence of a personal medical history, lack of satisfaction with pregnancy follow-up, and mode of delivery by caesarean section. Conclusion: Our study showed the high prevalence of PPD 展开更多
Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to hab...Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to habitat destruction.In China,these most-at-risk species are described as 'plant species with extremely small populations'(PSESP).Implementing conservation action for such listed species is urgent.Storing seeds is one of the main means of ex situ conservation for flowering plants.Spore storage could provide a simple and economical method for fern ex situ conservation.Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation.But what is known about the seed and spore biology(storage and germination) of at-risk species? We have used China's PSESP(the first group listing) as a case study to understand the gaps in knowledge on propagule biology of threatened plant species.We found that whilst germination information is available for 28 species(23%of PSESP),storage characteristics are only known for 8%of PSESP(10 species).Moreover,we estimate that 60%of the listed species may require cryopreservation for long-term storage.We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.展开更多
A coal outburst is a severe safety hazard in room-and-pillar mining under deep cover. It is more likely to occur during pillar retreating. Multi-seam mining dramatically increases the risk of coal outburst within the ...A coal outburst is a severe safety hazard in room-and-pillar mining under deep cover. It is more likely to occur during pillar retreating. Multi-seam mining dramatically increases the risk of coal outburst within the influence zones created by remnant pillars and gob-solid boundaries. Though coal outburst is generally associated with heavy loading of coal pillars,its occurrence is difficult to predict. Risk management provides a proactive tool to minimize coal outburst in room-and-pillar mining under deep cover. Risk assessment is the first step in identifying and quantifying outburst risk factors. The primary risk factors for coal outburst are overburden depth,roof and floor strength,geological anomalies,mining type,multi-seam mining,and panel width. A risk assessment chart can be used to proactively screen out mining sections with high risk of coal outburst for further analysis. Gob-solid boundaries and remnant pillars are critical factors in evaluation of the coal outburst risk of multi-seam mining. Risk identification,risk assessment,geologic influence mapping,geotechnical evaluation,risk analysis,risk mitigation,and monitoring are essential elements of coal outburst risk management process. Training is an integral part of risk management for risk identification and communication between all the stakeholders including management,technical and safety personnel,and miners.展开更多
Introduction-Objective: COVID-19 is a highly transmissible but often mild viral infection. However, some patients can present severe COVID-19 and subsequently die. The aim of the present study was to assess the risk f...Introduction-Objective: COVID-19 is a highly transmissible but often mild viral infection. However, some patients can present severe COVID-19 and subsequently die. The aim of the present study was to assess the risk factors for COVID-19 related death during the first three waves of the disease at the Epidemic Treatment Center (ETC) of Dakar Principal Hospital (DPH). Method: We conducted a descriptive and analytical perspective survival study from April 4, 2020 to September 25, 2021, including adult patients with COVID-19, hospitalized at the ETC of DPH. Log Rank test and multivariate Cox model were performed to identify risk factors for death. Results: We included 556 COVID-19 patients with mean age of 57 ± 17 years and a male-to-female ratio of 1.26. The number of deaths during one month of follow-up was 41, representing a cumulative risk of 7.4%. The log Rank test showed that being from the third wave (p = 0.0056), advanced age (p = 0.00098), presence of at least one comorbidity (p = 0.034), High blood pressure (p = 0.024), d-dimer level ≥ 1000 IU/L (p Conclusion: Our study showed that elderly and third-wave of COVID-19 patients were more at risk to die. Knowledge of risk factors for COVID-19 related death could improve the prognosis of these patients.展开更多
Purpose: The multifidus muscle is an important extensor muscle of the lumbar spine. It plays a major role in the stability and realization of axial rotation movements of the thoraco-lumbar spine. Its atrophy by fatty ...Purpose: The multifidus muscle is an important extensor muscle of the lumbar spine. It plays a major role in the stability and realization of axial rotation movements of the thoraco-lumbar spine. Its atrophy by fatty degeneration would be at the origin of the occurrence of chronic low back pain which constitutes a public health problem in Senegal. Taking into account its anatomy is essential for the etiopathogenic analysis and the treatment of low back pain. The purpose of our work was to investigate the impact of multifidus muscle morphometry on the anatomy-clinical evolution of low back pain. Material and method: this was a prospective study over a period of 30 months from November 2019 to May 2022. It involved 100 patients seen in the neurology department of Fann Hospital for chronic low back pain and who had already had a scanner falling within the criteria for low back pain. We used 3D Slicer, SPSS 20, Excel 2016 software to model and analyze the morphometric data of the multifidus muscle after physiotherapy and control lumbar scans. Results: The sex ratio was 2.23. The average age of the patients was 45 ± 7 years. On the initial CT scan, according to the Hadar classification, we noted a predominance of grade 2 with 56% in L5/S1, followed by grade 1 with 32% and grade 3 with 14%. In L4/L5, the majority of patients, 67%, had grade 1. A conflicting circumferential disc bulge with the roots predominating in L5/S1 was present in 94% of men (p-value = 0.02). Before physiotherapy, the average volume of the multifidus was 193 mm<sup>3</sup> ± 39, after physiotherapy it was 203 mm<sup>3</sup> ± 42 with a progression rate of 5.2%. Clinically, severe type pain had regressed from 86% before physiotherapy to 0% after physiotherapy (p-value = 0.03). Conclusion: Taking into account the morphometry of the multifidus is an essential element in the management of chronic low back pain.展开更多
The paper reported a theoretical study on the photoconductivity of a bifacial silicon solar cell under polychromatic illumination and a constant magnetic field effect. By use of the continuity equation in the base of ...The paper reported a theoretical study on the photoconductivity of a bifacial silicon solar cell under polychromatic illumination and a constant magnetic field effect. By use of the continuity equation in the base of the solar cell maintained in a constant temperature at 300 K, an expression of the excess minority carriers’ density was determined according to the applied magnetic field, the base depth and the junction recombination velocity. From the expression of the minority carriers’ density, the photoconductivity of the solar cell was deduced and which allowed us to predict some recombination phenomena, the use of such solar cell in optoelectronics. The profile of the photoconductivity also permitted us to utilize a linear model in order to determine an electrical capacitance that varied with magnetic field.展开更多
Senegal is a country of the Sahel. In this region, most of the populations live from agro-pastoral activities. The northern zone of Senegal is strongly influenced by river cultures. And the dynamics of the Senegal Riv...Senegal is a country of the Sahel. In this region, most of the populations live from agro-pastoral activities. The northern zone of Senegal is strongly influenced by river cultures. And the dynamics of the Senegal River are dependent on rainfall. The rainfall in the area is very closely linked to the dynamics of the atmosphere. The study of the spatio-temporal variability of rainfall in the northern region of Senegal requires quality rainfall observation data. It includes the Ferlo and the Senegal River valley, in particular the regions of Louga (department of Linguère included), Saint-Louis (departments of Dagana and Podor included) and Matam. These stations have been defined since Le Borgne (1988). The difficulty of having quality rain observation data can be resolved by using more accessible and good quality satellite data. Using satellite data, namely MSWEP, CRU, TAMSAT, ARC and PERSIANN, we showed the return of precipitation that appeared in 2000 and the unimodal cycle of precipitation in our study area. These data were validated using the correlation coefficient, the bias, the RMSE and the Nash index with observation data from the Regional Study Center for the Improvement of Adaptation to Drought (CERASS). The CRU data is then retained. Thus, this study made it possible to show the zonal distribution of rainfall in the northern zone of Senegal.展开更多
Objectives: This paper aims to study the epidemiology and causes of fetal deaths in utero at Regional Hospital Amath Dansokho of Kedougou (RHADK). Methodology: This was a retrospective epidemiological study conducted ...Objectives: This paper aims to study the epidemiology and causes of fetal deaths in utero at Regional Hospital Amath Dansokho of Kedougou (RHADK). Methodology: This was a retrospective epidemiological study conducted at the Maternity Ward of the Regional Hospital Amath Dansokho of Kedougou from June 01, 2022 to June 30, 2023, including all patients seen for delivery care. Data were analyzed using Statistical Package for Social Science (SPSS 22, Windows version). The parameters studied were the frequency of in-utero fetal death, sociodemographic characteristics, pregnancy and delivery data, neonatal data and cause-of-death classification according to the Cause of Death and Associated Conditions (CODAC) classification. Results: We recorded 1628 deliveries, with 231 cases of in-utero fetal death, a frequency of 14.2%. Fetal death occurred most frequently in multiparous women (64.5%). The majority of patients (72.3%) were transferred. 51.9% of patients with fetal death had at least 3 antenatal visits. On admission, fetal heart rate was absent in 73.2% of patients. The etiology of in-utero fetal death was dominated by maternal factors (high blood pressure, anaemia and diabetes), which accounted for 36.9% of deaths, followed by placental pathologies (retroplacental haematoma) and intrapartum pathologies (uterine rupture, abnormal presentation). Conclusion: In-utero fetal death can be prevented, and is mainly due to direct obstetric complications. The focus should be on the prevention and management of hypertensive disorders and their complications during pregnancy, the fight against anaemia and, above all, the rapid and correct management of dystocia.展开更多
Two-dimensional(2D)layered oxides have recently attracted wide attention owing to the strong coupling among charges,spins,lattice,and strain,which allows great flexibility and opportunities in structure designs as wel...Two-dimensional(2D)layered oxides have recently attracted wide attention owing to the strong coupling among charges,spins,lattice,and strain,which allows great flexibility and opportunities in structure designs as well as multifunctionality exploration.In parallel,plasmonic hybrid nanostructures exhibit exotic localized surface plasmon resonance(LSPR)providing a broad range of applications in nanophotonic devices and sensors.A hybrid material platform combining the unique multifunctional 2D layered oxides and plasmonic nanostructures brings optical tuning into the new level.In this work,a novel self-assembled Bi2MoO6(BMO)2D layered oxide incorporated with plasmonic Au nanoinclusions has been demonstrated via one-step pulsed laser deposition(PLD)technique.Comprehensive microstructural characterizations,including scanning transmission electron microscopy(STEM),differential phase contrast imaging(DPC),and STEM tomography,have demonstrated the high epitaxial quality and particle-in-matrix morphology of the BMO-Au nanocomposite film.DPC-STEM imaging clarifies the magnetic domain structures of BMO matrix.Three different BMO structures including layered supercell(LSC)and superlattices have been revealed which is attributed to the variable strain states throughout the BMO-Au film.Owing to the combination of plasmonic Au and layered structure of BMO,the nanocomposite film exhibits a typical LSPR in visible wavelength region and strong anisotropy in terms of its optical and ferromagnetic properties.This study opens a new avenue for developing novel 2D layered complex oxides incorporated with plasmonic metal or semiconductor phases showing great potential for applications in multifunctional nanoelectronics devices.展开更多
基金The project was supported in part by the National Research Initiative of the USDA Cooperative State Research,Education and Extension Service,grant number 2003-35503-13990.
文摘The accuracy of extracting projected pig area is critical to the accuracy of the weight measurement of pigs by machine vision.The capability of both the conventional and the edge detection methods for extracting pig area was examined using the images of 47 pigs of different weights.Relationship between the threshold value and the extracted area was numerically analyzed for both methods.It was found that the accuracy of the conventional method depended heavily on the threshold value,while choice of threshold value in the edge detection approach had no influence on the extracted area over a wide range.In normal lighting conditions,both methods yielded comparable values of predicted weight;however,under variable light intensities,the edge detection method was superior to the conventional method,because the former was proven to be independent of light intensities.This makes edge detection an ideal method for area extraction during the walk-through weighing process where pigs are allowed to move around.
文摘A development of an acquisition of the characteristic of a solar panel by automatic load variation system is put into play and coupled to an instrumentation chain for taking account of temperature. A programmed digital microprocessor control enables this automation. Design and implementation of a device for automation of variations of the resistive load are powered by solar panel. It is provided by a PIC 16F877A running a computer program that we have developed on the basis of an algorithm according to the operation that we have set. By varying automatically the resistive load, we were able to automatically acquire the characteristic I-V and temperature of the solar panel. With automatic combinations of the 10 resistors, we have obtained 1024 measures of the characteristic curve of the solar cell which has a good accuracy. The change in load and temperature measurement allows us to have the characteristic curves parameterized by temperature.
文摘In static regime with polychromatic illumination, using the expression of the solar cell capacitance to determine the silicon solar cell capacitance C<sub>0</sub>(T) in short-circuit, is the purpose of this article. The expression of the excess minority carries density δ(x) from the continuity equation. The expression of δ(x) is used to determine the photovoltage expression. The capacitance efficiency dependence on X<sub>cc</sub>(T) is studied. X<sub>cc</sub>(T) is the abscissa of the maximum of δ(x).
文摘This study assesses the chemical quality of water resources in the Lower Senegal River valley, based on 35 samples collected in November 2022. Major ion concentrations in surface water and groundwater were analyzed using classical geochemical interpretation diagrams (Piper, GIBBS, etc.) and multivariate geostatistical analyses, including hierarchical cluster analysis (HCA) and principal component analysis (PCA). The results revealed three types of facies: Ca-Mg-HCO3-type facies, characteristic of poorly mineralized waters such as surface waters and groundwater from dune formations and the alluvial plain close to the hydraulic axis;Na-Cl type facies associated with well waters located in the alluvial plain that tap Inchirian or Nouakchottian shallow reservoirs and Maastrichtian deep borehole waters;and mixed Ca-Cl and Na-HCO3 type facies observed in certain floodplain and dune reservoirs. The results showed a strong correlation between sodium, chlorides, bromides, and electrical conductivity, indicating a significant contribution of these ions to groundwater mineralization. The various sources of water mineralization include mixing processes between surface water or rainwater, or calcite or dolomite dissolution processes (for weakly mineralized waters), basic exchanges or inverse basic exchanges between the aquifer and the water table (for moderately mineralized waters), and evaporation processes, halite dissolution, and paleosalinity during periods of marine transgression and regression (for highly mineralized waters). The study also highlighted the high vulnerability of the alluvial aquifer to pollution from intensive irrigated agriculture, as significant quantities of sulfates and nitrates were measured in some samples. These results also highlight the importance of water quality management in the Lower Senegal Valley, particularly as concerns the protection of the alluvial aquifer against pollution from irrigated agriculture.
文摘West Africa was hit by an unprecedented drought in the 1970’s and 1980’s years, with dramatic consequences for surface and groundwater resources. In the context of climate change, there are many studies for the prediction of the increase in the occurrence of these droughts. To predict this situation in the Senegalese region, it is necessary to use regional climate models, which carrying out the study. This work deals with the interest to examine the capacity of the RCMs (regional climate models) in order to reproduce the deficit on the 1970’s year rainfall in Senegal. In this work, we used daily precipitation data from five (5) regional climate models to characterize the droughts in Senegal by using the SPI (Standardized Precipitation Index) on different time scales (3, 6, 12 and 24 months). For this purpose, the index was calculated over two distinct periods: 1951-1969 and 1970-1990. The results show that the period 1970-1990 was drier than the period 1951-1969. For the zonal average, the results show that the North of Senegal was more affected by this deficit rainfall than the South part. The analysis of the interannual variability of rainfall for some stations in Senegal shows that the drought did not start at the same time throughout the zone.
文摘Introduction: Postpartum depression is the most common psychiatric disorder affecting women in the perinatal period. According to the WHO, it affects 10% - 15% of women who have just given birth. In Africa, and particularly in Senegal, epidemiological studies focusing exclusively on postpartum depression are rare or non-existent. For this reason, we conducted this screening study on postpartum depression to assess the socio-demographic characteristics and associated factors. Methods: This was a prospective cross- sectional study with descriptive and analytical aims. It was carried out in the twelve Dakar referral health centres during the period August 2021 to June 2022. Results: At the end of our survey we had recruited one hundred and twenty-two (122) participants with a PPD prevalence rate of 25.41%. The most common age group was 24 - 29 years. 40% of the participants were of Fulani ethnicity, followed by Wolof. Married women made up 93% of the sample. The school enrolment rate was 89%. Most participants were not in paid employment. Domestic violence was present in 14% of couples. 28% of mothers reported experiencing a stressful life event during their pregnancy. 22% of the women had a chronic medical condition, of which 55% had high blood pressure. 1% of the women reported a personal psychiatric history and 5% a family psychiatric history. Most women had between two and four healthy living children. The pregnancy was unwanted in 17% of cases and 12% of participants had a complication. 6% were dissatisfied with the quality of their antenatal care. The caesarean section rate was 18%. In terms of associated factors, eight factors were identified in a bivariate analysis: single marital status, lack of support from partner, domestic violence, conflict with in-laws, and the occurrence of a stressful life event during pregnancy, the presence of a personal medical history, lack of satisfaction with pregnancy follow-up, and mode of delivery by caesarean section. Conclusion: Our study showed the high prevalence of PPD
基金Funding (No. U1302262) to W.B. Sun from the NSFC-Yunnan joint fund on key projects is gratefully acknowledgedThe Royal Botanic Gardens, Kew receives grant-in-aid from Defra+1 种基金This joint work was undertaken under the Memorandum of Agreement (2014e24) on Plant and Fungal Science between the Chinese Academy of Sciences and the Trustees of the Royal Botanic Gardens, KewHWP thanks Darwin Initiative Project 21-003 on cycads for funding
文摘Approximately one fifth of the world's plants are at risk of extinction.Of these,a significant number exist as populations of few individuals,with limited distribution ranges and under enormous pressure due to habitat destruction.In China,these most-at-risk species are described as 'plant species with extremely small populations'(PSESP).Implementing conservation action for such listed species is urgent.Storing seeds is one of the main means of ex situ conservation for flowering plants.Spore storage could provide a simple and economical method for fern ex situ conservation.Seed and spore germination in nature is a critical step in species regeneration and thus in situ conservation.But what is known about the seed and spore biology(storage and germination) of at-risk species? We have used China's PSESP(the first group listing) as a case study to understand the gaps in knowledge on propagule biology of threatened plant species.We found that whilst germination information is available for 28 species(23%of PSESP),storage characteristics are only known for 8%of PSESP(10 species).Moreover,we estimate that 60%of the listed species may require cryopreservation for long-term storage.We conclude that comparative biology studies are urgently needed on the world's most threatened taxa so that conservation action can progress beyond species listing.
文摘A coal outburst is a severe safety hazard in room-and-pillar mining under deep cover. It is more likely to occur during pillar retreating. Multi-seam mining dramatically increases the risk of coal outburst within the influence zones created by remnant pillars and gob-solid boundaries. Though coal outburst is generally associated with heavy loading of coal pillars,its occurrence is difficult to predict. Risk management provides a proactive tool to minimize coal outburst in room-and-pillar mining under deep cover. Risk assessment is the first step in identifying and quantifying outburst risk factors. The primary risk factors for coal outburst are overburden depth,roof and floor strength,geological anomalies,mining type,multi-seam mining,and panel width. A risk assessment chart can be used to proactively screen out mining sections with high risk of coal outburst for further analysis. Gob-solid boundaries and remnant pillars are critical factors in evaluation of the coal outburst risk of multi-seam mining. Risk identification,risk assessment,geologic influence mapping,geotechnical evaluation,risk analysis,risk mitigation,and monitoring are essential elements of coal outburst risk management process. Training is an integral part of risk management for risk identification and communication between all the stakeholders including management,technical and safety personnel,and miners.
文摘Introduction-Objective: COVID-19 is a highly transmissible but often mild viral infection. However, some patients can present severe COVID-19 and subsequently die. The aim of the present study was to assess the risk factors for COVID-19 related death during the first three waves of the disease at the Epidemic Treatment Center (ETC) of Dakar Principal Hospital (DPH). Method: We conducted a descriptive and analytical perspective survival study from April 4, 2020 to September 25, 2021, including adult patients with COVID-19, hospitalized at the ETC of DPH. Log Rank test and multivariate Cox model were performed to identify risk factors for death. Results: We included 556 COVID-19 patients with mean age of 57 ± 17 years and a male-to-female ratio of 1.26. The number of deaths during one month of follow-up was 41, representing a cumulative risk of 7.4%. The log Rank test showed that being from the third wave (p = 0.0056), advanced age (p = 0.00098), presence of at least one comorbidity (p = 0.034), High blood pressure (p = 0.024), d-dimer level ≥ 1000 IU/L (p Conclusion: Our study showed that elderly and third-wave of COVID-19 patients were more at risk to die. Knowledge of risk factors for COVID-19 related death could improve the prognosis of these patients.
文摘Purpose: The multifidus muscle is an important extensor muscle of the lumbar spine. It plays a major role in the stability and realization of axial rotation movements of the thoraco-lumbar spine. Its atrophy by fatty degeneration would be at the origin of the occurrence of chronic low back pain which constitutes a public health problem in Senegal. Taking into account its anatomy is essential for the etiopathogenic analysis and the treatment of low back pain. The purpose of our work was to investigate the impact of multifidus muscle morphometry on the anatomy-clinical evolution of low back pain. Material and method: this was a prospective study over a period of 30 months from November 2019 to May 2022. It involved 100 patients seen in the neurology department of Fann Hospital for chronic low back pain and who had already had a scanner falling within the criteria for low back pain. We used 3D Slicer, SPSS 20, Excel 2016 software to model and analyze the morphometric data of the multifidus muscle after physiotherapy and control lumbar scans. Results: The sex ratio was 2.23. The average age of the patients was 45 ± 7 years. On the initial CT scan, according to the Hadar classification, we noted a predominance of grade 2 with 56% in L5/S1, followed by grade 1 with 32% and grade 3 with 14%. In L4/L5, the majority of patients, 67%, had grade 1. A conflicting circumferential disc bulge with the roots predominating in L5/S1 was present in 94% of men (p-value = 0.02). Before physiotherapy, the average volume of the multifidus was 193 mm<sup>3</sup> ± 39, after physiotherapy it was 203 mm<sup>3</sup> ± 42 with a progression rate of 5.2%. Clinically, severe type pain had regressed from 86% before physiotherapy to 0% after physiotherapy (p-value = 0.03). Conclusion: Taking into account the morphometry of the multifidus is an essential element in the management of chronic low back pain.
文摘The paper reported a theoretical study on the photoconductivity of a bifacial silicon solar cell under polychromatic illumination and a constant magnetic field effect. By use of the continuity equation in the base of the solar cell maintained in a constant temperature at 300 K, an expression of the excess minority carriers’ density was determined according to the applied magnetic field, the base depth and the junction recombination velocity. From the expression of the minority carriers’ density, the photoconductivity of the solar cell was deduced and which allowed us to predict some recombination phenomena, the use of such solar cell in optoelectronics. The profile of the photoconductivity also permitted us to utilize a linear model in order to determine an electrical capacitance that varied with magnetic field.
文摘Senegal is a country of the Sahel. In this region, most of the populations live from agro-pastoral activities. The northern zone of Senegal is strongly influenced by river cultures. And the dynamics of the Senegal River are dependent on rainfall. The rainfall in the area is very closely linked to the dynamics of the atmosphere. The study of the spatio-temporal variability of rainfall in the northern region of Senegal requires quality rainfall observation data. It includes the Ferlo and the Senegal River valley, in particular the regions of Louga (department of Linguère included), Saint-Louis (departments of Dagana and Podor included) and Matam. These stations have been defined since Le Borgne (1988). The difficulty of having quality rain observation data can be resolved by using more accessible and good quality satellite data. Using satellite data, namely MSWEP, CRU, TAMSAT, ARC and PERSIANN, we showed the return of precipitation that appeared in 2000 and the unimodal cycle of precipitation in our study area. These data were validated using the correlation coefficient, the bias, the RMSE and the Nash index with observation data from the Regional Study Center for the Improvement of Adaptation to Drought (CERASS). The CRU data is then retained. Thus, this study made it possible to show the zonal distribution of rainfall in the northern zone of Senegal.
文摘Objectives: This paper aims to study the epidemiology and causes of fetal deaths in utero at Regional Hospital Amath Dansokho of Kedougou (RHADK). Methodology: This was a retrospective epidemiological study conducted at the Maternity Ward of the Regional Hospital Amath Dansokho of Kedougou from June 01, 2022 to June 30, 2023, including all patients seen for delivery care. Data were analyzed using Statistical Package for Social Science (SPSS 22, Windows version). The parameters studied were the frequency of in-utero fetal death, sociodemographic characteristics, pregnancy and delivery data, neonatal data and cause-of-death classification according to the Cause of Death and Associated Conditions (CODAC) classification. Results: We recorded 1628 deliveries, with 231 cases of in-utero fetal death, a frequency of 14.2%. Fetal death occurred most frequently in multiparous women (64.5%). The majority of patients (72.3%) were transferred. 51.9% of patients with fetal death had at least 3 antenatal visits. On admission, fetal heart rate was absent in 73.2% of patients. The etiology of in-utero fetal death was dominated by maternal factors (high blood pressure, anaemia and diabetes), which accounted for 36.9% of deaths, followed by placental pathologies (retroplacental haematoma) and intrapartum pathologies (uterine rupture, abnormal presentation). Conclusion: In-utero fetal death can be prevented, and is mainly due to direct obstetric complications. The focus should be on the prevention and management of hypertensive disorders and their complications during pregnancy, the fight against anaemia and, above all, the rapid and correct management of dystocia.
基金This work was supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences(BES)under Award DESC0020077.D.Z.,J.S.,Z.S.,and H.W.acknowledge the support from the U.S.Office of Naval Research under contract Nos.N00014-20-1-2043 for the TEM work and N00014-20-1-2600 for the thin film growth effort.The work at Los Alamos National Laboratory was supported by the NNSA’s Laboratory Directed Research and Development Program and was performed,in part,at the Center for Integrated Nanotechnologies,an Office of Science User Facility operated for the U.S.Department of Energy Office of Science.Los Alamos National Laboratory,an affirmative action equal opportunity employer,is managed by Triad National Security,LLC for the U.S.Department of Energy’s NNSA,under contract 89233218CNA000001.
文摘Two-dimensional(2D)layered oxides have recently attracted wide attention owing to the strong coupling among charges,spins,lattice,and strain,which allows great flexibility and opportunities in structure designs as well as multifunctionality exploration.In parallel,plasmonic hybrid nanostructures exhibit exotic localized surface plasmon resonance(LSPR)providing a broad range of applications in nanophotonic devices and sensors.A hybrid material platform combining the unique multifunctional 2D layered oxides and plasmonic nanostructures brings optical tuning into the new level.In this work,a novel self-assembled Bi2MoO6(BMO)2D layered oxide incorporated with plasmonic Au nanoinclusions has been demonstrated via one-step pulsed laser deposition(PLD)technique.Comprehensive microstructural characterizations,including scanning transmission electron microscopy(STEM),differential phase contrast imaging(DPC),and STEM tomography,have demonstrated the high epitaxial quality and particle-in-matrix morphology of the BMO-Au nanocomposite film.DPC-STEM imaging clarifies the magnetic domain structures of BMO matrix.Three different BMO structures including layered supercell(LSC)and superlattices have been revealed which is attributed to the variable strain states throughout the BMO-Au film.Owing to the combination of plasmonic Au and layered structure of BMO,the nanocomposite film exhibits a typical LSPR in visible wavelength region and strong anisotropy in terms of its optical and ferromagnetic properties.This study opens a new avenue for developing novel 2D layered complex oxides incorporated with plasmonic metal or semiconductor phases showing great potential for applications in multifunctional nanoelectronics devices.
