[Objective] This study was conducted to screen the best fertilization mode for potted Cymbidium sinense 'Qihei'. [Method] According to the contents of the N, P and K elements in C. sinense 'Qihei' and the main fer...[Objective] This study was conducted to screen the best fertilization mode for potted Cymbidium sinense 'Qihei'. [Method] According to the contents of the N, P and K elements in C. sinense 'Qihei' and the main fertilization modes used by producers and related literature information, the effects of 8 kinds of fertilization models on the growth of C. sinense 'Qihei' were studied. Twenty six morphologic and physiological indexes of C. sinense 'Qihei' growth were measured. [Result] Significant differences were shown on 21 indexes. [Conclusion] Based on the 26 in- dexes, the best fertilization mode included the steps of applying 14-14-14 (N-P20^- K20) slow-release fertilizer particles (8 g per bag) once in April, July and October, respectively; drip-applying 800 times of 30-10-10 water-soluble fertilizer once every half a month from April to September; and drip-applying 800 times of 15-5-30 wa- ter-soluble fertilizer (150 ml) once every half a month from October to December.展开更多
[Objective] The aim was to explore biomass and growth of Cupressus lusitanica seedlings in order to provide technological supports for afforestation. [Method] The introduced Cupressus lusitanica seedlings at different...[Objective] The aim was to explore biomass and growth of Cupressus lusitanica seedlings in order to provide technological supports for afforestation. [Method] The introduced Cupressus lusitanica seedlings at different ages were re- searched to explore biomass (ground or underground) morphological shape, surface area and volume of a root system. [Result] As age grew, plant height and ground diameter increased significantly, varying dramatically upon seed provenance, and root-canopy ratio, root length, surface area and volume of seedlings were increas- ing. Specifically, seedlings at two-year-old and three-year-old kept a stable growth; moderate and big roots took higher proportions in a root system; underground parts for a plant required more photosynthetic products; root systems of young seedlings grew to moderate and big roots. [Conclusion] Ground biomass is of correlation with root system indices and the morphological characteristics of root systems are close to biomass. The accumulation capacity of biomass differed for seedlings from differ- ent provenances, even in the same environment and at the same time.展开更多
Graphene under high temperature was prepared and loaded on Ni foam.Then,cobalt tetroxide precursor was grown on Ni foam in situ by the hydrothermal method.Finally,the sample was burned at high temperature to obtain Co...Graphene under high temperature was prepared and loaded on Ni foam.Then,cobalt tetroxide precursor was grown on Ni foam in situ by the hydrothermal method.Finally,the sample was burned at high temperature to obtain Co_(3)O_(4)+graphene@Ni.The hydrothermal method used in this paper is easy to operate,with low-risk factors and environmental protection.The prepared Co_(3)O_(4)+graphene@Ni electrode exhibits superior electrochemical performance than Co_(3)O_(4)@Ni electrode.At a current density of 1 A/g,the specific capacitance of the Co_(3)O_(4)+graphene@Ni electrode calculated by a charge-discharge test is 935 F/g,which is much larger than that of Co_(3)O_(4)@Ni electrode of 340 F/g.展开更多
Photocatalytic hydrogen peroxide(H_(2)O_(2))production is a promising strategy to replace the traditional production processes;however,the inefficient H_(2)O_(2) productivity limits its application.In this study,oxyge...Photocatalytic hydrogen peroxide(H_(2)O_(2))production is a promising strategy to replace the traditional production processes;however,the inefficient H_(2)O_(2) productivity limits its application.In this study,oxygen-rich g-C_(3)N_(4) with abundant nitrogen vacancies(OCN)was synthesized for photocatalytic H_(2)O_(2) production.X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy indicated that oxygen-containing functional groups(–COOH and C–O–C)were obtained.Electron paramagnetic resonance confirmed the successful introduction of nitrogen vacancies.OCN exhibited efficient photocatalytic H_(2)O_(2) production performance of 1965μmol L^(−1) h^(−1) in air under visible-light irradiation.The high H_(2)O_(2) production was attributed to the enhanced adsorption of oxygen,enlarged specific surface area,and promoted carrier separation.An increased H_(2)O_(2) production rate(5781μmol L^(−1) h^(−1))was achieved in a Na_(3)PO_(4) solution.The improved performance was attributed to the changed reactive oxygen species.Specifically,the adsorbed PO_(4)^(3−) on the surface of the OCN promoted the transfer of holes to the catalyst surface.•O_(2)−obtained by O_(2) reduction reacted with adjacent holes to generate 1O_(2),which could efficiently generate H_(2)O_(2) with isopropanol.Additionally,PO_(4)^(3−),as a stabilizer,inhibited the decomposition of H_(2)O_(2).展开更多
Besides carbon solubility, the carbide formation possibility is another important factor to differentiate various substrate materials in graphene growth. A recent experiment indicates that the formation of transition ...Besides carbon solubility, the carbide formation possibility is another important factor to differentiate various substrate materials in graphene growth. A recent experiment indicates that the formation of transition metal carbides (TMCs) can suppress carbon precipitation. In this study, Mo2C, a representative of TMCs, is used to study the effects of carbide formation in graphene growth from first principles. Carbon diffusion in Mo2C bulk turns out to be very difficult and it becomes much easier on the Mo2C(001) surface. Therefore, carbon precipitation suppression and graphene growth can be realized simultaneously. A direction depended diffusion behavior is observed on the Mo2C(101) surface, which makes it less favorable for graphene growth compared to the (001) surface.展开更多
This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wast...This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wastewater samples containing lead of different concentrations, and the growth rate was determined by light at wavelength of 560 nm. The 72 h-EC50 (72 h medium effective concentration) was estimated to be 11.46 mg/L (lead). Afterwards, the lead adsorption by live spirulina cells was conducted. It was observed that at the initial stage (0–12 min) the adsorption rate was so rapid that 74% of the metal was bio- logically adsorbed. The maximum biosorption capacity of live spirulina was estimated to be 0.62 mg lead per 105 alga cells.展开更多
Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop b...Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop better citizens first, and better workers later. The objective of this research was to detect different perceptions related to values and education. Using a 13 items questionnaire, we measured: Students' perceptions about him/herself as part of their education role, responsibility that students show toward activities m school, perceptions about education as a tool to grow in the social ladder and as a way of social recognition, social perception about effort as an important value to self-improve and get social recognition, and to finish, perceptions about their teacher's performance.展开更多
A general, simple and economic synthetic method for synthesizing carbon nanofibers was presented. In the method, ethanol was employed as carbon source; metal salts such as nickel nitrate, ferric nitrate and ferric chl...A general, simple and economic synthetic method for synthesizing carbon nanofibers was presented. In the method, ethanol was employed as carbon source; metal salts such as nickel nitrate, ferric nitrate and ferric chloride were used as catalyst precursor respectively; copper plate was employed as the support material. A lot of products were obtained by catalytic combustion deposition of ethanol vapor. Then the as-prepared carbon nanofibers were characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, energy dispersion X-ray spectroscopy and selected-area electron diffractometry. By analyzing the results of characterization, the conclusions are as follows: 1) the large catalyst particles tend to form large-diameter CNFs, small catalyst particles are inclinable to form small-diameter CNFs; 2) the morphology of the catalyst can affect the final morphology of the CNFs. Moreover, the possible growth mechanisms were proposed and the degree of graphitization of samples was estimated by Raman spectroscopy characterization.展开更多
The Federal Commission for Protection against Health Risks in Mexico (COFEPRIS) is responsible for the regulation and health promotion of the production, commercialization, import, export, publicity or involuntary e...The Federal Commission for Protection against Health Risks in Mexico (COFEPRIS) is responsible for the regulation and health promotion of the production, commercialization, import, export, publicity or involuntary exposure of medicines and technologies for health. For its part, the Mexican Institute of Industrial Property (IMPI) is a decentralized public body with legal personality, own property and legal authority to administer the industrial property system in our country. In the year 2000, on September 19, the official journal published the linking of patents related to allopathic medicines and the sanitary registry. Objectives: To publicize the process of linking the Sanitary-Patent Registry as a case study to delimit the scope of the new pharmaceutical products. Methodology: Request the information to COFEPRIS for the registration of a new pharmaceutical product; Establish flow diagrams for the registration of: innovative products, generic products, biotech products and bio similar products; Integrate the documents in the dossier of the pharmaceutical product for sanitary registration; Elaborate sworn letter of non-invasion of patents and study of patents; Submit the Health Registry; Intergovernmental consultation. Sanitary Registry Results: Search of patents in databases to elaborate state of the art, to write letter under protest to say truth that is not invading any patent, when developing a composition of cetuximab, as generic product since the patent molecule expired in 2016 and 11 patents related to compositions, preparations and finished product preparation processes. Conclusions: COFEPRIS will determine through intergovernmental consultation with the IMPI whether or not a patent is invaded, according to the case it will grant the registration or send the corresponding prevention for cetuximab, in case that invading can also be a refusal of grant.展开更多
Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted elect...Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted electron transfer between SRB and a glassy carbon (GC) electrode. The RGSs were produced at high yield by a chemical sequence involving graphite oxidation, ultrasonic exfoliation of nanosheets, and N2H4 reduction. Cyclic voltammetric testing showed that the characteristic anodic peaks (around 0.3 V) might arise from the combination of bacterial membrane surface cytochrome c3 and the metabolic products of SRB. After 6 d, another anodic wave gradually increased to a maximum current peak and a third anodic signal became visible at around 0 V. The enhancements of two characteristic anodic peaks suggest that RSGs mediate electron-transfer kinetics between bacteria and the solid electrode. Manipulation of these recently-discovered electron-transport mechanisms will lead to significant advances in MFC engineering.展开更多
This paper reports the results acquired in a research work about "questionable" practices and behaviors in the academic production of researches and postgraduate social sciences and humanities studies of the program...This paper reports the results acquired in a research work about "questionable" practices and behaviors in the academic production of researches and postgraduate social sciences and humanities studies of the programs that are appointed by the National Program of Quality Postgraduate Studies (PNPC, by its acronym in Spanish) in Mexico. Through a qualitative methodology, the authors interpreted some of the arguments that explain and/or justify certain practices in relation to doubled production, authorship, and coauthorship of academic products. In this paper, the authors present and analyze the results that they obtained after reviewing documents produced by professors and students of six postgraduate programs that are taught in two Mexican public universities. At the same time, the authors examine some of the practices that take place within said programs, given the institutional demands of improving finished studies efficiency. One of the hypotheses of this work is the demands that are imposed by external evaluations of academic processes on professors and their programs in order to reach desirable rates with the purpose of maintaining or increasing the levels of productivity, gives way to certain practices that must be analyzed. This work's theoretic framework is constituted by the contributions of career sociology and professional ethics.展开更多
The teaching-learning process may have several obstacles; one of those would be a cultural situation of students. When the author refers to cultural situation, the author means the language or dialect that they speak....The teaching-learning process may have several obstacles; one of those would be a cultural situation of students. When the author refers to cultural situation, the author means the language or dialect that they speak. In the state of Puebla, Mexico, there are primary schools where the courses are taught to students who do not speak Spanish and they only speak their own dialect. On the other hand, the use of information and communication technologies in primary schools in Puebla is a fact but a main concern in schools is that the languages in which they are operated are Spanish. To analyze this situation, the author finds that turns out to be very important and with a negative effect on both the implementation and acceptance of a multimedia program in these schools, generating a technological gap between students. The government efforts are decimated because of this cultural divide prevalent in many communities in the state of Puebla and the increase of this situation when considering the illiterate population.展开更多
This study was carried out to determine the effect of 21 Citrus interstocks and the control Citrus macrophylla rootstock budded with Mexican lime (Citrus aurantifolia (Chistm.) Swingle) on growth and yield. Three ...This study was carried out to determine the effect of 21 Citrus interstocks and the control Citrus macrophylla rootstock budded with Mexican lime (Citrus aurantifolia (Chistm.) Swingle) on growth and yield. Three types of mandarin and 13 trifoliate types including "C-35" and "Benton" used as interstocks, developed vigorous trees similar or more productive than the control. "Morton" and "Benecke" citranges, "Pomeroy" trifoliate trifoliate orange and the "Severinia buxifolia" interstocks showed a moderated effect on tree growth. Flying dragon (FDT) and Hiryu trifoliate oranges performed as semi-dwarfing interstocks. These interstocks reduced the tree height, canopy volume and surface area covered by the foliage on 25%-35%, 20%-30% and 20%-30%, respectively, compared to the control. While most interstocks surpassed the assigned area of growth (24 m2) in the 7th year, "FDT" and "Hiryu" did that at the 10th year. These semi-dwarfing interstocks produced up to 80 kg/tree per year. Most treatments recorded the highest production from the 8th to 10th year, except FDT and Hiryu, which showed the highest yield (130 kg/tree) from the 5th to 7th year. This study provides useful results to face the huanglongbing (HLB) problem using moderate or semi-dwarfing interstocks for Mexican lime orchards in high density plantations.展开更多
Re-vegetation plays a fundamental role for erosion control and plant recovery in lands affected by gully erosion. Bioengineered practices facilitate the gullies rehabilitation. Objectives of the research were: 1) Iden...Re-vegetation plays a fundamental role for erosion control and plant recovery in lands affected by gully erosion. Bioengineered practices facilitate the gullies rehabilitation. Objectives of the research were: 1) Identify taxonomically the pioneer vegetation on each gully section; 2) Characterize vegetation distribution preferences and 3) Assess structural/functional traits to recognize erosion control key species. Bioengineering was applied in a watershed belonging to Sierra Madre del Sur, at Oaxaca, Mexico, on eight gullies, with local support and minimal investment. "La Mixteca" is a poor ecological and socio-economic region, comparable to other regions of the world. The Initial Floristic Composition(IFC) inventory is the baseline of the successional process. The transect method was used to determine the colonization of species. Cover abundance of registered species was estimated using the semi-quantitative scale of Braun-Blanquet. This procedure was repeated in five different positions(floor, hillslopes and tops), in the cross section of the gully. Throughcorrespondence analysis and clustering, the distribution of species was analyzed. Adequate responses were obtained in soil retention(quantity) and plant cover(existence and diversity); as measurable indicators of the bioengeneering works efficiency. Occupation of soil by native species from the Tropical Deciduous Forest was favored using live barriers. We detected species guilds with spatial distribution preferences in the gullies cross section. Plant cover characterization includes: native colonizer species, herbaceous, shrubby and trees of the forest community bordering the gully area, with cover abundance and structural/functional traits, useful to protect degraded areas. This spatial occupation process of plants responds to a secondary succession in gullies, where the proposed IFC model is correctly represented through bioengineering. Natural establishment of plants was successful by traits of species such as extensive root system and sexual/vegetative reproduction.展开更多
Garra imberba is widely distributed in China. At the moment, both Garra yiliangensis and G. hainanensis are treated as valid species, but they were initially named as a subspecies of G. pingi, a junior synonym of G. i...Garra imberba is widely distributed in China. At the moment, both Garra yiliangensis and G. hainanensis are treated as valid species, but they were initially named as a subspecies of G. pingi, a junior synonym of G. imberba. Garra alticorpora and G. nujiangensis also have similar morphological characters to G. imberba, but the taxonomic statuses and phylogenetic relationships of these species with G. imberba remains uncertain. In this study, 128 samples from the Jinshajiang, Red, Nanpanjiang, Lancangjiang, Nujiang Rivers as well as Hainan Island were measured while 1 mitochondrial gene and 1 nuclear intron of 24 samples were sequenced to explore the phylogenetic relationship of these five species. The results showed that G. hainanensis, G. yiliangensis, G. alticorpora and G. imberba are the same species with G. imberba being the valid species name, while G. nujiangensis is a valid species in and of itself.展开更多
This research examines Samoan student experiences in two Homework Study Groups (HSGs) in Melbourne using a researcher-practitioner approach. It highlights that school teachers need to acknowledge students' preferre...This research examines Samoan student experiences in two Homework Study Groups (HSGs) in Melbourne using a researcher-practitioner approach. It highlights that school teachers need to acknowledge students' preferred learning methods, especially those of minority backgrounds like the Samoan participants in this investigation. A detailed exploration of the experiences of students in two HSGs finds that while students and their families place a high priority on learning, their cultural practices are not compatible with standard Western learning approaches. The HSGs provided a social space in which students could ask the teacher questions without fear of appearing foolish, in which they could apply themselves to study. It provided a physical study space away from the demands some Samoan families place on their young people, and it provided a cultural space in which the students could learn according to fa'aSamoa (traditional values and beliefs). This research makes a contribution to an understanding of the motivations of Melbourne-based Samoan students to learn, of what concerns them, and of impediments to their educational success. It also offers insight into the benefits that set up a specific space for students offers, when its specific intent is influencing the merging of Samoan and Western ideas to further learning.展开更多
Mexico forest tenure structure is known worldwide for its progressive approach of giving local communities full property rights to set a robust support to sustainable livelihoods in forested areas. Most forest areas i...Mexico forest tenure structure is known worldwide for its progressive approach of giving local communities full property rights to set a robust support to sustainable livelihoods in forested areas. Most forest areas in Mexico are owned by local communities either through the ejido, agrarian indigenous community or groups of small owners. In the last 30 years, many forest communities explored forest production at a commercial scale, creating their own communal forestry business and concurring to national markets with their timber and non-timber products. The socio-economical impacts of this approach were tremendous, steadily improving communities living standards. This success prompted rural organizations to ask the Mexican government to launch programs to expand the "community forestry" model. With international assistance from the World Bank and other agencies, the government of Mexico launched three different programs to foster forest commons: the Forest Conservation and Management Program, the Indigenous, Communities and Biodiversity Project and the Mexican part of the Mesoamerican Biological Corridor. Performance of these programs has been assessed through the World Bank evaluation framework, but the question about their environmental impact or even about their environmental sustainability and therefore their validity as national policies has been scantily explored and practically not debated. To contribute to answering these questions, the author made an extensive analysis of their impact over forest cover during the 2003-2008 period using land cover maps and correlated them with institutional development variables, building a social organization and collective action index (SOCAI), following Elinor Ostrom institutional analysis and development framework (lAD).展开更多
The aim of this study was to evaluate the use of melengestrol acetate (MGA) as a strategy to improve the production efficiency in ewes of rural areas in Mexico. Twenty ewes of breeds (Dorper and Dorper with Pelibue...The aim of this study was to evaluate the use of melengestrol acetate (MGA) as a strategy to improve the production efficiency in ewes of rural areas in Mexico. Twenty ewes of breeds (Dorper and Dorper with Pelibuey) non-pregnant and with ovarica activity were used. The treatment consisted of the administration of 0.22 mg MGA/ewe/d for 17 d. The MGA efficiency was measured once the treatment finalized, and the producer was responsible for the registration of the estrus presentation and prolificacy rate. 95% of the sheep presented estrus in a period of 14 d after stopping treatment. The prolificacy percentage was of 1.2 lambs born by ewe during a period of six months (including treatment and period of gestation). In conclusion, the use of MGA represents an alternative to improve the efficiency of sheep production in rural areas in Mexico, since it can increase the number of lambs by 30% in a period of 12 months.展开更多
The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additiv...The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additives--chemicals, black mold enzyme, and chemicals together with black mold enzyme, are studied. The first part of the experiment was to find the optimal amount of chemicals and the optimal pH through the use of sodium hydroxide and surfactant. As a result, 0.2% of sodium hydroxide and 0.4% of surfactant on oven dried weight at pH 9 was found to be the optimal condition for the deinked pulp to yield the lowest ERIC (effective residual concentration) and the highest brightness. The second part of the experiment was to find the optimal amount of black mold enzyme used in the deinking process. As a result, the optimal condition for deinked pulp to retain the lowest ERIC and the highest brightness was 100 ppm of black mold enzyme and 10 minutes of enzyme reaction time. The third part of experiment was to study the de-inking ability of black mold enzyme and chemicals. Consequently, with 30 min of chemicals reaction time and 60 min of black mold reaction time, the deinked pulp retained low ERIC but higher brightness.展开更多
基金Supported by Science and Technology Planning Project of Guangdong Province(2012A020602036)
文摘[Objective] This study was conducted to screen the best fertilization mode for potted Cymbidium sinense 'Qihei'. [Method] According to the contents of the N, P and K elements in C. sinense 'Qihei' and the main fertilization modes used by producers and related literature information, the effects of 8 kinds of fertilization models on the growth of C. sinense 'Qihei' were studied. Twenty six morphologic and physiological indexes of C. sinense 'Qihei' growth were measured. [Result] Significant differences were shown on 21 indexes. [Conclusion] Based on the 26 in- dexes, the best fertilization mode included the steps of applying 14-14-14 (N-P20^- K20) slow-release fertilizer particles (8 g per bag) once in April, July and October, respectively; drip-applying 800 times of 30-10-10 water-soluble fertilizer once every half a month from April to September; and drip-applying 800 times of 15-5-30 wa- ter-soluble fertilizer (150 ml) once every half a month from October to December.
基金Supported by National Program "948"(2009-4-17)~~
文摘[Objective] The aim was to explore biomass and growth of Cupressus lusitanica seedlings in order to provide technological supports for afforestation. [Method] The introduced Cupressus lusitanica seedlings at different ages were re- searched to explore biomass (ground or underground) morphological shape, surface area and volume of a root system. [Result] As age grew, plant height and ground diameter increased significantly, varying dramatically upon seed provenance, and root-canopy ratio, root length, surface area and volume of seedlings were increas- ing. Specifically, seedlings at two-year-old and three-year-old kept a stable growth; moderate and big roots took higher proportions in a root system; underground parts for a plant required more photosynthetic products; root systems of young seedlings grew to moderate and big roots. [Conclusion] Ground biomass is of correlation with root system indices and the morphological characteristics of root systems are close to biomass. The accumulation capacity of biomass differed for seedlings from differ- ent provenances, even in the same environment and at the same time.
基金Project(21502014)supported by the National Natural Science Foundation of ChinaProjects(20180550736,2019-ZD 0117)supported by the Natural Science Foundation of Liaoning Province,China+1 种基金Projects(JDL 2019004,JDL 2017027)supported by the Research Foundation of Educational Committee of Liaoning Province,ChinaProject(191008-K)supported by Guangxi Key Laboratory of Information Materials(Guilin University of Electronic Technology),China。
文摘Graphene under high temperature was prepared and loaded on Ni foam.Then,cobalt tetroxide precursor was grown on Ni foam in situ by the hydrothermal method.Finally,the sample was burned at high temperature to obtain Co_(3)O_(4)+graphene@Ni.The hydrothermal method used in this paper is easy to operate,with low-risk factors and environmental protection.The prepared Co_(3)O_(4)+graphene@Ni electrode exhibits superior electrochemical performance than Co_(3)O_(4)@Ni electrode.At a current density of 1 A/g,the specific capacitance of the Co_(3)O_(4)+graphene@Ni electrode calculated by a charge-discharge test is 935 F/g,which is much larger than that of Co_(3)O_(4)@Ni electrode of 340 F/g.
文摘Photocatalytic hydrogen peroxide(H_(2)O_(2))production is a promising strategy to replace the traditional production processes;however,the inefficient H_(2)O_(2) productivity limits its application.In this study,oxygen-rich g-C_(3)N_(4) with abundant nitrogen vacancies(OCN)was synthesized for photocatalytic H_(2)O_(2) production.X-ray photoelectron spectroscopy and Fourier-transform infrared spectroscopy indicated that oxygen-containing functional groups(–COOH and C–O–C)were obtained.Electron paramagnetic resonance confirmed the successful introduction of nitrogen vacancies.OCN exhibited efficient photocatalytic H_(2)O_(2) production performance of 1965μmol L^(−1) h^(−1) in air under visible-light irradiation.The high H_(2)O_(2) production was attributed to the enhanced adsorption of oxygen,enlarged specific surface area,and promoted carrier separation.An increased H_(2)O_(2) production rate(5781μmol L^(−1) h^(−1))was achieved in a Na_(3)PO_(4) solution.The improved performance was attributed to the changed reactive oxygen species.Specifically,the adsorbed PO_(4)^(3−) on the surface of the OCN promoted the transfer of holes to the catalyst surface.•O_(2)−obtained by O_(2) reduction reacted with adjacent holes to generate 1O_(2),which could efficiently generate H_(2)O_(2) with isopropanol.Additionally,PO_(4)^(3−),as a stabilizer,inhibited the decomposition of H_(2)O_(2).
文摘Besides carbon solubility, the carbide formation possibility is another important factor to differentiate various substrate materials in graphene growth. A recent experiment indicates that the formation of transition metal carbides (TMCs) can suppress carbon precipitation. In this study, Mo2C, a representative of TMCs, is used to study the effects of carbide formation in graphene growth from first principles. Carbon diffusion in Mo2C bulk turns out to be very difficult and it becomes much easier on the Mo2C(001) surface. Therefore, carbon precipitation suppression and graphene growth can be realized simultaneously. A direction depended diffusion behavior is observed on the Mo2C(101) surface, which makes it less favorable for graphene growth compared to the (001) surface.
文摘This study examines the possibility of using live spirulina to biologically remove aqueous lead of low concentration (below 50 mg/L) from wastewater. The spirulina cells were first immersed for seven days in five wastewater samples containing lead of different concentrations, and the growth rate was determined by light at wavelength of 560 nm. The 72 h-EC50 (72 h medium effective concentration) was estimated to be 11.46 mg/L (lead). Afterwards, the lead adsorption by live spirulina cells was conducted. It was observed that at the initial stage (0–12 min) the adsorption rate was so rapid that 74% of the metal was bio- logically adsorbed. The maximum biosorption capacity of live spirulina was estimated to be 0.62 mg lead per 105 alga cells.
文摘Empirical research was done interviewing face to face a sample of 2,447, 10-12 grade students in Culiacan, Sinaloa, Mexico, from the main public university high school in town. Education is seen as a tool to develop better citizens first, and better workers later. The objective of this research was to detect different perceptions related to values and education. Using a 13 items questionnaire, we measured: Students' perceptions about him/herself as part of their education role, responsibility that students show toward activities m school, perceptions about education as a tool to grow in the social ladder and as a way of social recognition, social perception about effort as an important value to self-improve and get social recognition, and to finish, perceptions about their teacher's performance.
基金Project(66167044) supported by the Academic Human Resources Development in Institutions of Higher Learning under the Jurisdiction of Beijing, ChinaProject(66062021) supported by the Science and Technology Activity for Chinese Homecoming Fellow Abroad, Program of Beijing Key Laboratory for Sensor
文摘A general, simple and economic synthetic method for synthesizing carbon nanofibers was presented. In the method, ethanol was employed as carbon source; metal salts such as nickel nitrate, ferric nitrate and ferric chloride were used as catalyst precursor respectively; copper plate was employed as the support material. A lot of products were obtained by catalytic combustion deposition of ethanol vapor. Then the as-prepared carbon nanofibers were characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, energy dispersion X-ray spectroscopy and selected-area electron diffractometry. By analyzing the results of characterization, the conclusions are as follows: 1) the large catalyst particles tend to form large-diameter CNFs, small catalyst particles are inclinable to form small-diameter CNFs; 2) the morphology of the catalyst can affect the final morphology of the CNFs. Moreover, the possible growth mechanisms were proposed and the degree of graphitization of samples was estimated by Raman spectroscopy characterization.
文摘The Federal Commission for Protection against Health Risks in Mexico (COFEPRIS) is responsible for the regulation and health promotion of the production, commercialization, import, export, publicity or involuntary exposure of medicines and technologies for health. For its part, the Mexican Institute of Industrial Property (IMPI) is a decentralized public body with legal personality, own property and legal authority to administer the industrial property system in our country. In the year 2000, on September 19, the official journal published the linking of patents related to allopathic medicines and the sanitary registry. Objectives: To publicize the process of linking the Sanitary-Patent Registry as a case study to delimit the scope of the new pharmaceutical products. Methodology: Request the information to COFEPRIS for the registration of a new pharmaceutical product; Establish flow diagrams for the registration of: innovative products, generic products, biotech products and bio similar products; Integrate the documents in the dossier of the pharmaceutical product for sanitary registration; Elaborate sworn letter of non-invasion of patents and study of patents; Submit the Health Registry; Intergovernmental consultation. Sanitary Registry Results: Search of patents in databases to elaborate state of the art, to write letter under protest to say truth that is not invading any patent, when developing a composition of cetuximab, as generic product since the patent molecule expired in 2016 and 11 patents related to compositions, preparations and finished product preparation processes. Conclusions: COFEPRIS will determine through intergovernmental consultation with the IMPI whether or not a patent is invaded, according to the case it will grant the registration or send the corresponding prevention for cetuximab, in case that invading can also be a refusal of grant.
基金Supported by the National Natural Science Foundation of China (No.41076047)the Shandong Provincial Natural Science Foundation of China (No. ZR2010DM004)the Chinese Academy of Sciences (No. KZCX2-YW-205-03)
文摘Reduced graphene sheets (RGSs) mediate electron transfer between sulfate-reducing bacteria (SRB) and solid electrodes, and promote the development of microbial fuel cells (MFC). We have investigated RSG-promoted electron transfer between SRB and a glassy carbon (GC) electrode. The RGSs were produced at high yield by a chemical sequence involving graphite oxidation, ultrasonic exfoliation of nanosheets, and N2H4 reduction. Cyclic voltammetric testing showed that the characteristic anodic peaks (around 0.3 V) might arise from the combination of bacterial membrane surface cytochrome c3 and the metabolic products of SRB. After 6 d, another anodic wave gradually increased to a maximum current peak and a third anodic signal became visible at around 0 V. The enhancements of two characteristic anodic peaks suggest that RSGs mediate electron-transfer kinetics between bacteria and the solid electrode. Manipulation of these recently-discovered electron-transport mechanisms will lead to significant advances in MFC engineering.
文摘This paper reports the results acquired in a research work about "questionable" practices and behaviors in the academic production of researches and postgraduate social sciences and humanities studies of the programs that are appointed by the National Program of Quality Postgraduate Studies (PNPC, by its acronym in Spanish) in Mexico. Through a qualitative methodology, the authors interpreted some of the arguments that explain and/or justify certain practices in relation to doubled production, authorship, and coauthorship of academic products. In this paper, the authors present and analyze the results that they obtained after reviewing documents produced by professors and students of six postgraduate programs that are taught in two Mexican public universities. At the same time, the authors examine some of the practices that take place within said programs, given the institutional demands of improving finished studies efficiency. One of the hypotheses of this work is the demands that are imposed by external evaluations of academic processes on professors and their programs in order to reach desirable rates with the purpose of maintaining or increasing the levels of productivity, gives way to certain practices that must be analyzed. This work's theoretic framework is constituted by the contributions of career sociology and professional ethics.
文摘The teaching-learning process may have several obstacles; one of those would be a cultural situation of students. When the author refers to cultural situation, the author means the language or dialect that they speak. In the state of Puebla, Mexico, there are primary schools where the courses are taught to students who do not speak Spanish and they only speak their own dialect. On the other hand, the use of information and communication technologies in primary schools in Puebla is a fact but a main concern in schools is that the languages in which they are operated are Spanish. To analyze this situation, the author finds that turns out to be very important and with a negative effect on both the implementation and acceptance of a multimedia program in these schools, generating a technological gap between students. The government efforts are decimated because of this cultural divide prevalent in many communities in the state of Puebla and the increase of this situation when considering the illiterate population.
文摘This study was carried out to determine the effect of 21 Citrus interstocks and the control Citrus macrophylla rootstock budded with Mexican lime (Citrus aurantifolia (Chistm.) Swingle) on growth and yield. Three types of mandarin and 13 trifoliate types including "C-35" and "Benton" used as interstocks, developed vigorous trees similar or more productive than the control. "Morton" and "Benecke" citranges, "Pomeroy" trifoliate trifoliate orange and the "Severinia buxifolia" interstocks showed a moderated effect on tree growth. Flying dragon (FDT) and Hiryu trifoliate oranges performed as semi-dwarfing interstocks. These interstocks reduced the tree height, canopy volume and surface area covered by the foliage on 25%-35%, 20%-30% and 20%-30%, respectively, compared to the control. While most interstocks surpassed the assigned area of growth (24 m2) in the 7th year, "FDT" and "Hiryu" did that at the 10th year. These semi-dwarfing interstocks produced up to 80 kg/tree per year. Most treatments recorded the highest production from the 8th to 10th year, except FDT and Hiryu, which showed the highest yield (130 kg/tree) from the 5th to 7th year. This study provides useful results to face the huanglongbing (HLB) problem using moderate or semi-dwarfing interstocks for Mexican lime orchards in high density plantations.
基金World Wildlife Fund (WWF) for providing financial support for the conduction of the research through Oaxaca Community Foundationthe National Council for Science and Technology supported the first author through grant for two years
文摘Re-vegetation plays a fundamental role for erosion control and plant recovery in lands affected by gully erosion. Bioengineered practices facilitate the gullies rehabilitation. Objectives of the research were: 1) Identify taxonomically the pioneer vegetation on each gully section; 2) Characterize vegetation distribution preferences and 3) Assess structural/functional traits to recognize erosion control key species. Bioengineering was applied in a watershed belonging to Sierra Madre del Sur, at Oaxaca, Mexico, on eight gullies, with local support and minimal investment. "La Mixteca" is a poor ecological and socio-economic region, comparable to other regions of the world. The Initial Floristic Composition(IFC) inventory is the baseline of the successional process. The transect method was used to determine the colonization of species. Cover abundance of registered species was estimated using the semi-quantitative scale of Braun-Blanquet. This procedure was repeated in five different positions(floor, hillslopes and tops), in the cross section of the gully. Throughcorrespondence analysis and clustering, the distribution of species was analyzed. Adequate responses were obtained in soil retention(quantity) and plant cover(existence and diversity); as measurable indicators of the bioengeneering works efficiency. Occupation of soil by native species from the Tropical Deciduous Forest was favored using live barriers. We detected species guilds with spatial distribution preferences in the gullies cross section. Plant cover characterization includes: native colonizer species, herbaceous, shrubby and trees of the forest community bordering the gully area, with cover abundance and structural/functional traits, useful to protect degraded areas. This spatial occupation process of plants responds to a secondary succession in gullies, where the proposed IFC model is correctly represented through bioengineering. Natural establishment of plants was successful by traits of species such as extensive root system and sexual/vegetative reproduction.
基金supported by the National Natural Science Foundation of China(30730017,31160419)Yunnan Provincial Science and Technology Program(2009CC008)
文摘Garra imberba is widely distributed in China. At the moment, both Garra yiliangensis and G. hainanensis are treated as valid species, but they were initially named as a subspecies of G. pingi, a junior synonym of G. imberba. Garra alticorpora and G. nujiangensis also have similar morphological characters to G. imberba, but the taxonomic statuses and phylogenetic relationships of these species with G. imberba remains uncertain. In this study, 128 samples from the Jinshajiang, Red, Nanpanjiang, Lancangjiang, Nujiang Rivers as well as Hainan Island were measured while 1 mitochondrial gene and 1 nuclear intron of 24 samples were sequenced to explore the phylogenetic relationship of these five species. The results showed that G. hainanensis, G. yiliangensis, G. alticorpora and G. imberba are the same species with G. imberba being the valid species name, while G. nujiangensis is a valid species in and of itself.
文摘This research examines Samoan student experiences in two Homework Study Groups (HSGs) in Melbourne using a researcher-practitioner approach. It highlights that school teachers need to acknowledge students' preferred learning methods, especially those of minority backgrounds like the Samoan participants in this investigation. A detailed exploration of the experiences of students in two HSGs finds that while students and their families place a high priority on learning, their cultural practices are not compatible with standard Western learning approaches. The HSGs provided a social space in which students could ask the teacher questions without fear of appearing foolish, in which they could apply themselves to study. It provided a physical study space away from the demands some Samoan families place on their young people, and it provided a cultural space in which the students could learn according to fa'aSamoa (traditional values and beliefs). This research makes a contribution to an understanding of the motivations of Melbourne-based Samoan students to learn, of what concerns them, and of impediments to their educational success. It also offers insight into the benefits that set up a specific space for students offers, when its specific intent is influencing the merging of Samoan and Western ideas to further learning.
文摘Mexico forest tenure structure is known worldwide for its progressive approach of giving local communities full property rights to set a robust support to sustainable livelihoods in forested areas. Most forest areas in Mexico are owned by local communities either through the ejido, agrarian indigenous community or groups of small owners. In the last 30 years, many forest communities explored forest production at a commercial scale, creating their own communal forestry business and concurring to national markets with their timber and non-timber products. The socio-economical impacts of this approach were tremendous, steadily improving communities living standards. This success prompted rural organizations to ask the Mexican government to launch programs to expand the "community forestry" model. With international assistance from the World Bank and other agencies, the government of Mexico launched three different programs to foster forest commons: the Forest Conservation and Management Program, the Indigenous, Communities and Biodiversity Project and the Mexican part of the Mesoamerican Biological Corridor. Performance of these programs has been assessed through the World Bank evaluation framework, but the question about their environmental impact or even about their environmental sustainability and therefore their validity as national policies has been scantily explored and practically not debated. To contribute to answering these questions, the author made an extensive analysis of their impact over forest cover during the 2003-2008 period using land cover maps and correlated them with institutional development variables, building a social organization and collective action index (SOCAI), following Elinor Ostrom institutional analysis and development framework (lAD).
文摘The aim of this study was to evaluate the use of melengestrol acetate (MGA) as a strategy to improve the production efficiency in ewes of rural areas in Mexico. Twenty ewes of breeds (Dorper and Dorper with Pelibuey) non-pregnant and with ovarica activity were used. The treatment consisted of the administration of 0.22 mg MGA/ewe/d for 17 d. The MGA efficiency was measured once the treatment finalized, and the producer was responsible for the registration of the estrus presentation and prolificacy rate. 95% of the sheep presented estrus in a period of 14 d after stopping treatment. The prolificacy percentage was of 1.2 lambs born by ewe during a period of six months (including treatment and period of gestation). In conclusion, the use of MGA represents an alternative to improve the efficiency of sheep production in rural areas in Mexico, since it can increase the number of lambs by 30% in a period of 12 months.
文摘The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additives--chemicals, black mold enzyme, and chemicals together with black mold enzyme, are studied. The first part of the experiment was to find the optimal amount of chemicals and the optimal pH through the use of sodium hydroxide and surfactant. As a result, 0.2% of sodium hydroxide and 0.4% of surfactant on oven dried weight at pH 9 was found to be the optimal condition for the deinked pulp to yield the lowest ERIC (effective residual concentration) and the highest brightness. The second part of the experiment was to find the optimal amount of black mold enzyme used in the deinking process. As a result, the optimal condition for deinked pulp to retain the lowest ERIC and the highest brightness was 100 ppm of black mold enzyme and 10 minutes of enzyme reaction time. The third part of experiment was to study the de-inking ability of black mold enzyme and chemicals. Consequently, with 30 min of chemicals reaction time and 60 min of black mold reaction time, the deinked pulp retained low ERIC but higher brightness.