2,120 research outputs found
Smartphones in the teaching of Physics Laws: Projectile motion
New technologies are called upon to play an important role as beneficial tools for meaningful learning in the classroom. In particular, smartphones can be regarded as pocket computers that, in addition to a remarkable memory and computing capacity, incorporate sensors such as accelerometers, gyroscopes, magnetometers, light sensors, etc., which turn them into easily available measurement instruments for practical classes in an educational environment. In this study, the suitability of these devices for demonstrating Classical Mechanics, minimizing the use of resources and class time, has been assessed in two real classrooms (with 16 to 19 year-old students) by conducting experiments related to projectile motion (vertical free fall and parabolic motion). A simple methodology that only involves a mobile phone, a free burst camera application and open-source tools (GIMP and OpenOffice Calc) for data processing is presented. The results obtained in non-perfected conditions led to an estimate of the acceleration of gravity with an error lower than 2%. Further analyses and alternative procedures are also suggested in the discussion section. No major difficulties were encountered with the high school students or with the first year university ones, and a high degree of satisfaction was found
BYOD for physics lab: Studying Newton's law of cooling with a smartphone
In this paper we discuss a simple and inexpensive method to introduce students to Newton''s law of cooling using only their smartphones, according to the Bring-Your-Own-Device philosophy. A popular experiment in basic thermodynamics, both at a high-school and at University level, is the determination of the specific heat of solids and liquids using a water calorimeter, resourcing in many cases to a mercury thermometer. With our approach the analogical instrument is quickly turned into a digital device by analyzing the movement of the mercury with a video tracker. Tus, using very simple labware and the students'' smartphones or tablets, it is possible to observe the decay behavior of the temperature of a liquid lef to cool at room temperature. Te dependence of the time constant with the mass and surface of the liquid can be easily probed, and the results of the different groups in the classroom can be brought together to observe the linear dependence
Heavy metals in agricultural soils of the European Union with implications for food safety
Soil plays a central role in food safety as it determines the possible composition of food and feed at the root of the
food chain. However, the quality of soil resources as defined by their potential impact on human health by propagation
of harmful elements through the food chain has been poorly studied in Europe due to the lack of data of
adequate detail and reliability. The European Union's first harmonized topsoil sampling and coherent analytical
procedure produced trace element measurements fromapproximately 22,000 locations. This unique collection of
information enables a reliable overview of the concentration of heavy metals, also referred to as metal(loid)s including
As, Cd, Cr, Cu, Hg, Pb, Zn, Sb. Co, and Ni. In this article we propose that in some cases (e.g. Hg and Cd) the
high concentrations of soil heavy metal attributed to human activity can be detected at a regional level.While the
immense majority of European agricultural land can be considered adequately safe for food production, an estimated
6.24% or 137,000 km2 needs local assessment and eventual remediation action
VARIABILIDADE ESPACIAL E TEMPORAL DA MATURAÇÃO DE UVA PARA VINHO - VARIEDADES: ARAGONÊS, TRINCADEIRA.
O conceito de terroir no vinho é baseado na observação de que diferentes regiões, vinhas ou mesmo
secções diferentes dentro da mesma vinha, podem produzir vinhos com uma identidade muito própria
e bem diferente uns dos outros. Os franceses começaram a cristalizar este conceito como uma maneira
de descrever os aspectos originais de um determinado lugar (solo, topografia e clima), que influencia e
molda o vinho feito a partir dele.
Para uma determinada posição geográfica, podemos considerar que o solo e a topografia são fixos
no espaço e no tempo, mas não o clima. Na verdade, dentro da mesma vinha, várias regiões
microclimáticas podem ser definidas. Os microclimas de uma determinada vinha afectam
diferenciadamente a maturação das uvas, criando dessa forma uma variabilidade espacial e temporal
da qualidade da uva.
Foram analisadas duas variedades de uva, Aragonês e Trincadeira, e para cada variedade foram
estudados, respectivamente, 7 e 6 talhões dentro da vinha do CASITO, pertencente à Fundação
Eugénio de Almeida. Nestes talhões e nestas variedades, foi acompanhada a maturação das uvas em
três anos consecutivos.
Como resultado constatou-se que existe uma variabilidade espacial e temporal da maturação da uva
entre castas e dentro da mesma casta, abrindo desta forma, a possibilidade de gerir diferenciadamente
cada parcela
Do Texto Ao Contexto: O Programa Ensino Médio Inovador Em Movimento
This article provides an analysis of an educational policy based on the production of its referential texts. For this aim, the theoretical reflections of S. Ball on the Policy Cycle Approach are used. A recent educational policy, the Programa Ensino Médio Inovador (Innovative Middle School Program) - ProEMI, is studied in face of the documents produced in a short period of time as well as the intentions of the Program of bringing about changes in the High Secondary School curricular organization. The analysis points to a hypothesis that the alterations in the documents result, at least in part, from a process of accommodation between what is prescribed by the government agency and the conditions for the implementation of the Program as well as the breadth of the universe of interlocutors involved.249391093
Surface boundary layer characteristics over caatinga vegetation in tropical semiarid region of N-E Brazil
Some characteristic features of the atmospheric surface layer over
a tropical semiarid station Petrolina (9.9◦S, 40.22◦W, 365.5 m) in N-E Brazil, are
investigated, using data collected from a micrometeorological tower of 9 m height.
This study utilizes the wind, temperature, humidity and carbon dioxide (CO2) data
obtained for the month of July 2004. The diurnal variation of mean parameters
such as temperature, relative humidity, wind speed and CO2 are studied. Turbulent
statistics are computed using the eddy correlation technique, and are studied under
the framework of Monin-Obukhov similarity theory with results compared with other
experimental studies reported in the literature
Helium isotopes distribution in NW Iberian peninsula: evidences of a local neotectonic activity
In this work we report new data on He abundances and isotope ratios
(3He/4He) from gas associated to some thermal and CO2-rich mineral waters in
N-Portugal. Collected gas samples are mainly CO2-dominant except two sites
where gas is N2-rich. All the sampling sites are characterized by exceptionally
high helium contents with 3He/4He ratios, corrected for air contamination,
varying considerably from 0.09 to 2.68 Ra. In all sites, the 3He/4He ratios are
higher than that typical for stable continental areas thus indicating a variable but
not-negligible (up to 30%) contribution of mantle-derived primordial He. In all
the CO2-rich waters, CO2/3He ratios and 13CCO2 are comparable with mantle
values, thus suggesting a magmatic origin also for CO2. On the contrary, in the
N2-rich waters He is mainly radiogenic, and CO2 is organic in origin. Since no
recent volcanic activity is observed in NW Iberia, high 3He/4He values could be
due, at least, to three processes:
a) releasing of gas from the local upper mantle through deep extensional fault
systems; b) releasing of magmatic volatiles from crustal reservoir(s) formed
during past volcanic activity; c) degassing of a subsurface emplaced magma body.
Mantle He flux in N-Portugal has been estimated to be up to 3 orders of
magnitude higher than that typical for stable continental areas, thus suggesting,
in this area, the presence of a tensional tectonic regime. This implies that mantle
gases could migrate upward probably through inherited tectonic structures
reactivated by neotectonic activity. The third possible scenario seems to be less
plausible since seismic surveys carried out in NW Iberian did not find any
significant evidence of mantle intrusion in the crust. The observed spatial
variability in mantle-derived contribution could reflect the geometry of the
granitic plutons in this area, thus supporting the hypotheses of an upper mantle
degassing. Alternatively, it could be the result of a lateral migration of magmatic
volatiles stored in a crustal reservoir
Development of biodegradable, cellulose-based, essential oil and chitosan drug delivery systems for cosmetic mask applications
The goal of this research was the development of cellulose-based biodegradable drug delivery systems solutions for cosmetic mask applications. Cellulose-based materials derived from natural renewable sources provide a sustainable alternative to nonwoven cosmetic masks derived from nondegradable fossil-based raw materials. An experimental design was executed to assemble the 3D cellulose fibres matrix and the water in oil emulsion comprising the active molecules from Mentha piperita L. Two types of biopolymeric additives were used, one derived from a nano/micro fibrillated cellulose pulp and another one including chitosan. A 3D computational simulation study was performed to enhance porosity and strength properties. The results indicated that the cosmetic face mask optimized prototypes, made from a biodegradable 3D matrix of cellulose fibres and active molecules, are suitable for dermic usePostprint (published version
Nongenotoxic Effects And A Reduction Of The Dxr-induced Genotoxic Effects Of Helianthus Annuus Linné (sunflower) Seeds Revealed By Micronucleus Assays In Mouse Bone Marrow
Background: This research evaluated the genotoxicity of oil and tincture of H. annuus L. seeds using the micronucleus assay in bone marrow of mice. The interaction between these preparations and the genotoxic effects of doxorubicin (DXR) was also analysed (antigenotoxicity test) .Methods: Experimental groups were evaluated at 24-48 h post treatment with N-Nitroso-N-ethylurea (positive control - NEU), DXR (chemotherapeutic), NaCl (negative control), a sunflower tincture (THALS) and two sources of sunflower oils (POHALS and FOHALS). Antigenotoxic assays were carried out using the sunflower tincture and oils separately and in combination with NUE or DXR. Results: For THALS, analysis of the MNPCEs showed no significant differences between treatment doses (250-2,000 mg.Kg-1) and NaCl. A significant reduction in MNPCE was observed when THALS (2,000 mg.Kg-1) was administered in combination with DXR (5 mg.Kg-1). For POHALS or FOHALS, analysis of the MNPCEs also showed no significant differences between treatment doses (250-2,000 mg.Kg-1) and NaCl. However, the combination DXR + POHALS (2,000 mg.Kg-1) or DXR + FOHALS (2,000 mg.Kg-1) not contributed to the MNPCEs reduction. Conclusions: This research suggests absence of genotoxicity of THALS, dose-, time- and sex-independent, and its combination with DXR can reduce the genotoxic effects of DXR. POHALS and FOHALS also showed absence of genotoxicity, but their association with DXR showed no antigenotoxic effects. © 2014 Boriollo et al.; licensee BioMed Central Ltd.14Sunflowers: Helianthus (Compositae-Heliantheae) (1976) Evolution of Crop Plants, pp. 36-38. , London: Longmans Green, Simmonds NW, Heiser CBEarle, F.R., Vanetten, C.H., Clark, T.F., Wolff, I.A., Compositional data on sunflower seed (1968) J Am Oil Chem Soc, 45, pp. 876-879Salunkhe, D.K., Chavan, J.K., Adsule, R.N., Kadam, S.S., World Oilseeds: Chemistry, Technology and Utilization (1992) Sunflower, , New York: Van Nostrand ReinholdGonzáles-Pérez, S., Vereijken, J.M., Sunflower proteins: Overview of their physicochemical, structural and functional properties (2007) J Sci Food Agric, 87, pp. 2173-2191Warner, K.A., Mounts, T.L., List, G.V.R., Effects of added tocopherols on the flavor stability of purified vegetable oils (1990) Inform, 1, p. 326Ito, T., Tamura, T., Matsumoto, T., Sterol Composition of 19 vegetable oils (1973) J Am Oil Chem Soc, 50, pp. 122-125. , 10.1007/BF02633564, 4707293Trost, V.W., Characterization of corn oil, soybean oil and sunflower oil nonpolar material (1989) J Am Oil Chem Soc, 66, pp. 325-333Dupont, H.L., Sullivan, P., Evans, D.G., Vollet, J.J., Ericsson, C.D., Ackerman, P.B., Tjoa, W.S., Prevention of traveler's diarrhea (emporiatric enteritis). Prophylactic administration of subsalicylate bismuth (1980) JAMA, 243, pp. 237-241. , 10.1001/jama.1980.03300290019013, 6985681Cowan, J.C., Key factors and recent advances in the flavor stability of soybean oil (1966) J Am Oil Chem Soc, 43, pp. 300A-302A. , 318A, 320, 10.1007/BF02682424, 5328054Bierenbaum, M.L., Fleischman, A.I., Dun, J., Arnold, J., Possible toxic waste factor in coronary heart disease (1975) Lancet, 1, pp. 1008-1010Purves, D., Harvey, C., Tweats, D., Lumley, C.E., Genotoxity testing: current practices and strategies used by the pharmaceutical industry (1995) Mutagenesis, 10, pp. 297-312. , 10.1093/mutage/10.4.297, 7476265Varanda, E.A., Atividade mutagênica de plantas medicinais (2006) Rev Ciênc Farm Básica Apl, 27, pp. 1-7Mateuca, R., Lombaert, N., Aka, P.V., Decordier, I., Kirsch-Volders, M., Chromosomal changes: induction, detection methods and applicability in human biomonitoring (2006) Biochimie, 88, pp. 1515-1531. , 10.1016/j.biochi.2006.07.004, 16919864Krishna, G., Hayashi, M., In vivo rodent micronucleus assay: protocol, conduct and data interpretation (2000) Mutat Res, 455, pp. 155-166. , 10.1016/S0027-5107(00)00117-2, 11113474(1997) OECD Guideline for the Testing of Chemicals: Bacterial reverse mutation test, p. 471. , Paris, Organisation for Economic Cooperation and Development(1997) OECD Guideline for the Testing of Chemicals: In vitro mammalian chromosome aberration test, p. 473. , Paris, Organisation for Economic Cooperation and Development(1997) OECD Guideline for the Testing of Chemicals: Mammalian erythrocyte micronucleus test, p. 474. , Paris, Organisation for Economic Cooperation and DevelopmentAlves, J.M., Munari, C.C., Neto, M.A.B.M., Furtado, R.A., Senedese, J.M., Bastos, J.K., Tavares, D.C., In vivo protective effect of Copaifera langsdorffii hydroalcoholic extract on micronuclei induction by doxorubicin (2013) J Appl Toxicol, 33, pp. 854-860. , 10.1002/jat.2777, 22611044Indart, A., Viana, M., Clapés, S., Izquierdo, L., Bonet, B., Clastogenic and cytotoxic effects of lipid peroxidation products generated in culinary oils submitted to thermal stress (2007) Food Chem Toxicol, 45, pp. 1963-1967. , 10.1016/j.fct.2007.04.019, 17573172Venkatesh, P., Shantala, B., Jagetia, G.C., Rao, K.K., Baliga, M.S., Modulation of Doxorubicin-Induced Genotoxicity by Aegle marmelos in Mouse Bone Marrow: A Micronucleus Study (2007) Integr Cancer Ther, 6, pp. 42-53. , 10.1177/1534735406298302, 17351026(2010) Farmacopéia Brasileira, Agência Nacional de Vigilância Sanitária - ANVISA/Fundação Oswaldo, , Brasília: Cruz - FIOCRUZ, BrasilSex differences in the micronucleus test (1986) Mutat Res, 172, pp. 151-163. , Collaborative Study Group for the Micronucleus Test (CSGMT)Zambrano, M.A., Targa, H.J., Rabello-Gay, M.N., Physiological saline solutions as a useful tool in micronucleus and metaphase slide preparations (1982) Stain Technol, 57, pp. 48-49Lewi, D.M., Hopp, H.E., Escandon, A.S., Sunflower (Helianthus annuus L.) (2006) Methods Mol Biol, 343, pp. 291-297Heo, J.C., Woo, S.U.K., Kweon, M.A., Park, J.Y., Lee, H.K., Son, M., Rho, J.R., Lee, S.H., Aqueous extract of the Helianthus annuus seed alleviates asthmatic symptoms in vivo (2008) Int J Mol Med Chem, 21, pp. 57-61Cardoso, C.C., Rodrigues, K.L., Pichara, N.L., Dall'Aglio, R., Fiorini, J.E., Fraschini, F., Diana, G.M., Carvalho, J.C.T., Olio di girasole ozonizzato associate ad acido α-lipoico e a lattobacilli: studio pre-clinico dell'azione antiulcerosa, antinfiammatoria e antibatterica (2004) Farmaci, 28, pp. 97-110Ricardo, G.A., Zullyt, Z.R., Yilian, L., Hernández, F., Menéndez, S., Efecto del OLEOZON® frente a lesiones gástricas inducidas por indometacina en ratas (Effect of OLEOZON® on gastric lesions induced by indomethacin in rats) (2007) Revista electrónica de Veterinaria, 8, pp. 1-6Rodrigues, K.L., Cardoso, C.C., Caputo, L.R., Carvalho, J.C., Fiorini, J.E., Schneedorf, J.M., Cicatrizing and antimicrobial properties of an ozonised oil from sunflower seeds (2004) Inflammopharmacology, 3, pp. 261-270Akihisa, T., Yasukawa, K., Oinuma, H., Kasahara, Y., Kimura, Y., Takase, S., Yamanouchi, S., Tamura, T., Triterpene alcohols from the flowers of Compositae and their anti-inflammatory effects (1996) Phytochemistry, 43, pp. 1255-1260. , 10.1016/S0031-9422(96)00343-3, 8987908Rojas-Molina, M., Campos-Sanches, J., Analla, M., Serrano, M., Moraga, A.A., Genotoxicity of vegetable cooking oils in the Drosophila wing spot test (2005) Environ Mol Mutagen, 45, pp. 90-95. , 10.1002/em.20078, 15611939Montero, A.C.R., Carvajal, Y.G., Rodríguez, Z.Z., López, G.F., Mirabal, J.M., Evaluación genotóxica del OLEOZON mediante los ensayos de micronúcleos en medula ósea y sangre periférica de ratón (1998) Revista CENIC: Ciências Biológicas, 29, pp. 200-202Salerno, J.W., Smith, D.E., The use of sesame oil and other vegetable oils in the inhibition of human colon cancer growth in vitro (1991) Anticancer Res, 11, pp. 209-215Cognault, S., Jourdan, M.L., Germain, E., Pitavy, R., Morel, E., Durand, G., Bougnoux, P., Lhuillery, C., Effect of an m-linolenic acid-rich diet on rat mammary tumour growth depends on the dietary oxidative status (2000) Nutr Cancer, 36, pp. 33-41. , 10.1207/S15327914NC3601_6, 10798214Nakayama, M., Ju, H.R., Sugano, M., Hirose, N., Ueki, T., Doi, F., Eynard, A.R., Effect of dietary fat and cholesterol on dimethylbenz [a]-antracene-induced mammary tumorigenesis in Sprague-Dawley rats (1993) Anticancer Res, 13, pp. 691-698La Vecchia, C., Negri, E., Franceschi, S., Decarli, A., Giacosa, A., Lipworth, L., Olive oil, other dietary fats, and the risk of breast cancer (Italy) (1995) Cancer Cause Control, 6, pp. 545-550Rao, G.N., Ney, E., Herbert, R.A., Effect of melatonin and linolenic acid on mammary cancer in transgenic mice with c-neu breast cancer oncogen (2000) Breast Cancer Res, 64, pp. 287-296Burns, C.P., Luttenegger, D.G., Specctor, A.A., Effect of dietary fat saturation on survival of mice with L1210 Leukemia (1978) J Natl Cancer Inst, 61, pp. 513-515Bartsch, H., Nai, J., Owen, R.W., Dietary polyunsaturated fatty acids and cancer of the breast and colorectum: emerging evidence for their role as risk modifiers (1999) Carcinogenesis, 20, pp. 2209-2218. , 10.1093/carcin/20.12.2209, 10590211Boovens, J., Engelbrecht, P., Le Roux, S., Louwrens, C.C., Van der Merwe, C.F., Katzeff, I.E., Some effects of the essential fatty acids linoleic acid and alpha-Linolenic acid and of their metabolites gamma-Linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahesaenoic acid, and of prostaglandins A1 and E1 in the proliferation of human osteogenic sarcoma cells in culture (1984) Prostaglandins Leukot Med, 15, pp. 15-33. , 10.1016/0262-1746(84)90053-2, 6089235Johanning, G.L., Lin, T.Z., Unsaturated fatty acid effects on human breast cancer cell adhesion (1995) Nutr Cancer, 24, pp. 57-66. , 10.1080/01635589509514393, 7491298Newcomer, L.M., King, I.B., Wicklund, K.G., Stanford, J.L., The association of fatty acids with prostate cancer risk (2001) Prostate, 47, pp. 262-268. , 10.1002/pros.1070, 11398173Iwado, H., Naito, M., Hayatsu, H., Genotoxicity and antigenotoxicity of air-borne particulates (1991) Mutat Res, 246, pp. 93-103. , 10.1016/0027-5107(91)90110-A, 1986270Siegel, I., Liu, T.L., Yaghoubzadeh, E., Keskey, T.S., Gleicher, N., Cytotoxic effects of free fatty acids on ascites tumor cells (1987) J Natl Cancer Inst Monographs, 78, pp. 271-277Bégin, L.R., Clement, P.B., Kirk, M.E., Jothy, S., McCaughey, W.T., Ferenczy, A., Aggressive angiomyxoma of pelvic soft parts: a clinicopathologic study of nine cases (1985) Hum Pathol, 16, pp. 621-628. , 10.1016/S0046-8177(85)80112-X, 3997139Ramon, J.M., Bou, R., Romea, S., Alkiza, M.E., Jacas, M., Ribes, J., Oromi, J., Dietary fat intake and prostate cancer risk: a case-control study in Spain (2000) Cancer Cause Control, 11, pp. 679-685DeFlora, S., Ramel, C., Mechanisms of inhibitors of mutagenesis and carcinogenesis: classification and review (1988) Mutat Res, 202, pp. 285-306. , 10.1016/0027-5107(88)90193-5, 3057362Visioli, F., Bellosta, S., Galli, C., Oleuropein, the bitter principle of olives, enhances nitric-oxide production by mouse macrophages (1998) Life Sci, 62, pp. 541-546. , 10.1016/S0024-3205(97)01150-8, 9464466Santos, J.H., Graf, U., Reguly, M.L., De Andrade, H.H.R., The synergistic effects of vanillin on recombination predominate over its antigenotoxic action in relation to MMC-induced lesions in somatic cells of Drosophila melanogaster (1999) Mutat Res, 444, pp. 355-365. , 10.1016/S1383-5718(99)00101-1, 10521675Weisburger, J.H., Can cancer risks be altered by changing nutritional traditions? (1998) Cancer, 83, pp. 1278-1281. , 10.1002/(SICI)1097-0142(19981001)83:73.0.CO;2-F, 9762926Katiyar, S.K., Mohan, R.R., Agarwal, R., Mukhtar, H., Protection against induction of mouse skin papillomas with low and high risk of conversion to malignancy by green tea polyphenols (1997) Carcinogenesis, 18, pp. 497-502. , 10.1093/carcin/18.3.497, 9067548Indart, A., Viana, M., Grootveld, M.C., Silwood, C.J., Sanchez-Vera, I., Bonet, B., Teratogenic actions of thermally-stressed culinary oils in rats (2002) Free Radic Res Commun Commun, 36, pp. 1051-1058Al-Shabanah, O.A., Inhibition of adriamycin-induced micronuclei by desferrioxamine in Swiss albino mice (1993) Mutat Res, 301, pp. 107-111. , 10.1016/0165-7992(93)90032-Q, 7678167Bean, C.L., Armstrong, M.J., Galloway, S.M., Effect of sampling time on chromosome aberration yield for 7 chemicals in Chinese hamster ovary cells (1992) Mutat Res, 265, pp. 31-44. , 10.1016/0027-5107(92)90037-3, 1370241Delvaeye, M., Verovski, V., De Neve, W., Storme, G., DNA breakage, cytotoxicity, drug accumulation and retention in two human ovarian tumor cell lines AZ224 and AZ364 treated with adriamycin, modulated by verapamil (1993) Anticancer Res, 13, pp. 1533-1538Dhawan, A., Kayani, M.A., Parry, J.M., Parry, E., Anderson, D., Aneugenic and clastogenic effects of doxorubicin in human lymphocytes (2003) Mutagenesis, 18, pp. 487-490. , 10.1093/mutage/geg024, 14614182Jagetia, G.C., Nayak, V., Effect of doxorubicin on cell survival and micronuclei formation in HeLa cells exposed to different doses of gamma-radiation (2000) Strahlenther Onkol, 176, pp. 422-428. , 10.1007/PL00002351, 11050916Vidhya, N., Devraj, S.N., Antioxidant effect of eugenol in rat intestine (1999) Ind J Exp Biol, 37, pp. 1192-119
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