75 FR 68401 - Duncan Smith and Gerald Altizer-Continuance in Control Exemption-Eighteen Thirty Group, LLC and...

Science.gov (United States)

2010-11-05

... DEPARTMENT OF TRANSPORTATION Surface Transportation Board [Docket No. FD 35436] Duncan Smith and..., LLC Duncan Smith and Gerald Altizer (collectively applicants), noncarrier individuals, have filed a... carriers. Mr. Smith owns 80% of Eighteen Thirty and 75% of Georges Creek. Mr. Altizer owns a 20% interest...

Search for B{r_arrow}{mu}{bar {nu}}{sub {mu}}{gamma} and B{r_arrow}e{bar {nu}}{sub e}{gamma}

Energy Technology Data Exchange (ETDEWEB)

Browder, T.E.; Li, F.; Li, Y.; Rodriguez, J.L. [University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Johnson, E.; Karliner, I.; Palmer, M.; Selen, M.; Thaler, J.J. [University of Illinois, Champaign-Urbana, Illinois 61801 (United States); Edwards, K.W. [Carleton University, Ottawa, Ontario, K1S 5B6 (Canada); Bellerive, A.; Britton, D.I.; Janicek, R.; MacFarlane, D.B.; McLean, K.W.; Patel, P.M. [McGill University, Montreal, Quebec, H3A 2T8 (Canada); Sadoff, A.J. [Ithaca College, Ithaca, New York 14850 (United States); Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Darling, C.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N. [University of Kansas, Lawrence, Kansas 66045 (United States); Anderson, S.; Kubota, Y.; Lattery, M.; ONeill, J.J.; Patton, S.; Poling, R.; Riehle, T.; Smith, A.; Savinov, V. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Severini, H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Blinov, S.; Duboscq, J.E.; Fulton, R.; Fujino, D.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P.; Wood, M. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; Yurko, M. [Purdue University, West Lafayette, Indiana 47907 (United States); Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Schaffner, S.F.; Ugolini, D.; Wang, R.; Zhou, X.; and others

1997-07-01

We have searched for the decays B{r_arrow}{mu}{bar {nu}}{sub {mu}}{gamma} and B{r_arrow}e{bar {nu}}{sub e}{gamma} in a sample of 2.7{times}10{sup 6} charged B decays collected with the CLEO II detector. In the muon channel, we observe no candidates in the signal region and set an upper limit on the branching fraction of B(B{r_arrow}{mu}{bar {nu}}{sub {mu}}{gamma}){lt}5.2{times}10{sup {minus}5} at the 90{percent} confidence level. In the electron channel, we observe five candidates in the signal region and set an upper limit on the branching fraction of B(B{r_arrow}e{bar {nu}}{sub e}{gamma}){lt}2.0{times}10{sup {minus}4} at the 90{percent} confidence level. {copyright} {ital 1997} {ital The American Physical Society}

Majorization arrow in quantum-algorithm design

International Nuclear Information System (INIS)

Latorre, J.I.; Martin-Delgado, M.A.

2002-01-01

We apply majorization theory to study the quantum algorithms known so far and find that there is a majorization principle underlying the way they operate. Grover's algorithm is a neat instance of this principle where majorization works step by step until the optimal target state is found. Extensions of this situation are also found in algorithms based in quantum adiabatic evolution and the family of quantum phase-estimation algorithms, including Shor's algorithm. We state that in quantum algorithms the time arrow is a majorization arrow

Relation between the psychological and thermodynamic arrows of time

Science.gov (United States)

Mlodinow, Leonard; Brun, Todd A.

2014-05-01

In this paper we lay out an argument that generically the psychological arrow of time should align with the thermodynamic arrow of time where that arrow is well defined. This argument applies to any physical system that can act as a memory, in the sense of preserving a record of the state of some other system. This result follows from two principles: the robustness of the thermodynamic arrow of time to small perturbations in the state, and the principle that a memory should not have to be fine-tuned to match the state of the system being recorded. This argument applies even if the memory system itself is completely reversible and nondissipative. We make the argument with a paradigmatic system, and then formulate it more broadly for any system that can be considered a memory. We illustrate these principles for a few other example systems and compare our criteria to earlier treatments of this problem.

Book Symposium: Duncan Pritchard, Epistemic Angst (Princeton University Press, 2015, xiii + 236 pages

Directory of Open Access Journals (Sweden)

Duncan Pritchard

Full Text Available ABSTRACT This book symposium features three critical pieces dealing with Duncan Pritchard's book, 'Epistemic Angst'; the symposium also contains Pritchard's replies to his critics.

Conflict Tasks of Different Types Divergently Affect the Attentional Processing of Gaze and Arrow.

Science.gov (United States)

Fan, Lingxia; Yu, Huan; Zhang, Xuemin; Feng, Qing; Sun, Mengdan; Xu, Mengsi

2018-01-01

The present study explored the attentional processing mechanisms of gaze and arrow cues in two different types of conflict tasks. In Experiment 1, participants performed a flanker task in which gaze and arrow cues were presented as central targets or bilateral distractors. The congruency between the direction of the target and the distractors was manipulated. Results showed that arrow distractors greatly interfered with the attentional processing of gaze, while the processing of arrow direction was immune to conflict from gaze distractors. Using a spatial compatibility task, Experiment 2 explored the conflict effects exerted on gaze and arrow processing by their relative spatial locations. When the direction of the arrow was in conflict with its spatial layout on screen, response times were slowed; however, the encoding of gaze was unaffected by spatial location. In general, processing to an arrow cue is less influenced by bilateral gaze cues but is affected by irrelevant spatial information, while processing to a gaze cue is greatly disturbed by bilateral arrows but is unaffected by irrelevant spatial information. Different effects on gaze and arrow cues by different types of conflicts may reflect two relatively distinct specific modes of the attentional process.

Liquid Core ARROW Waveguides: A Promising Photonic Structure for Integrated Optofluidic Microsensors

Directory of Open Access Journals (Sweden)

Genni Testa

2016-03-01

Full Text Available In this paper, we introduce a liquid core antiresonant reflecting optical waveguide (ARROW as a novel optofluidic device that can be used to create innovative and highly functional microsensors. Liquid core ARROWs, with their dual ability to guide the light and the fluids in the same microchannel, have shown great potential as an optofluidic tool for quantitative spectroscopic analysis. ARROWs feature a planar architecture and, hence, are particularly attractive for chip scale integrated system. Step by step, several improvements have been made in recent years towards the implementation of these waveguides in a complete on-chip system for highly-sensitive detection down to the single molecule level. We review applications of liquid ARROWs for fluids sensing and discuss recent results and trends in the developments and applications of liquid ARROW in biomedical and biochemical research. The results outlined show that the strong light matter interaction occurring in the optofluidic channel of an ARROW and the versatility offered by the fabrication methods makes these waveguides a very promising building block for optofluidic sensor development.

Measurement of the {ital D}{sup +}{sub {ital s}}{r_arrow}{eta}l{sup +}{nu} and {ital D}{sup +}{sub {ital s}}{r_arrow}{eta}{prime}l{sup +}{nu} branching ratios

Energy Technology Data Exchange (ETDEWEB)

Brandenburg, G.; Cinabro, D.; Liu, T.; Saulnier, M.; Wilson, R.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Palmer, M.; Selen, M.; Thaler, J.J.; Edwards, K.W.; McLean, K.W.; Ogg, M.; Bellerive, A.; Britton, D.I.; Hyatt, E.R.F.; Janicek, R.; MacFarlane, D.B.; Patel, P.M.; Spaan, B.; Sadoff, A.J.; Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Copty, N.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N.; Kubota, Y.; Lattery, M.; Momayezi, M.; Nelson, J.K.; Patton, S.; Poling, R.; Savinov, V.; Schrenk, S.; Wang, R.; Alam, M.S.; Kim, I.J.; Ling, Z.; Mahmood, A.H.; O`Neill, J.J.; Severini, H.; Sun, C.R.; Wappler, F.; Crawford, G.; Duboscq, J.E.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; White, C.; Wolf, A.; Zoeller, M.M.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Miao, T.; Miller, D.H.; Modesitt, M.; Shibata, E.I.; Shipsey, I.P.J.; Wang, P.N.; Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H.; Coan, T.E.; Dominick, J.; Fadeyev, V.; Korolkov, I.; Lambrecht, M.; Sanghera, S.; Shelkov, V.; Skwarnicki, T.; Stroynowski, R.; Volobouev, I.; Wei, G.; Artuso, M.; Gao, M.; Goldberg, M.; He, D.; Horwitz, N.; Kopp, S.; Moneti, G.C.; Mountain, R.; Muheim, F.; Mukhin, Y.; Playfer, S.; Stone, S.; Xing, X.; Bartelt, J.; Csorna, S.E.; Jain, V.; Marka, S.; Gibaut, D.; Kinoshita, K.; Pomianowski, P.; Barish, B.; Chadha, M.; Chan, S.; Cowen, D.F.; Eigen, G.; Miller, J.S.; O`Grady, C.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F.; Asner, D.M.; Athanas, M.; Bliss, D.W.; Brower, W.S.; Masek, G.; Paar, H.P.; Gronberg, J.; Korte, C.M.; Kutschke, R.; Menary, S.; Morrison, R.J.; Nakanishi, S.; Nelson, H.N.; Nelson, T.K.; Qiao, C.; Richman, J.D.; Roberts, D.; Ryd, A.; Tajima, H.; Witherell, M.S.; Balest, R.; Cho, K.; Ford, W.T.; Lohner, M.; Park, H.; Rankin, P.; Smith, J.G.; Alexander, J.P.; (CLEO Collaborat...

1995-11-20

Using the CLEO II detector we measure {ital B}({ital D}{sup +}{sub {ital s}}{r_arrow}{eta}{ital e}{sup +}{nu})/{ital B}({ital D}{sup +}{sub {ital s}}{r_arrow}{phi}{ital e}{sup +}{nu}) =1.24{plus_minus}0.12{plus_minus}0.15, {ital B}({ital D}{sup +}{sub {ital s}}{r_arrow}{eta}{prime}{ital e}{sup +}{nu})/{ital B} ({ital D}{sup +}{sub {ital s}}{r_arrow}{phi}{ital e}{sup +}{nu})=0.43{plus_minus}0.11{plus_minus}0.07, and {ital B}({ital D}{sup +}{sub {ital s}}{r_arrow}{eta}{prime}{ital e}{sup +}{nu})/{ital B} ({ital D}{sup +}{sub {ital s}}{r_arrow}{eta}{ital e}{sup +}{nu})=0.35{plus_minus}0.09{plus_minus}0.07. We find the ratio of vector to pseudoscalar final states, {ital B}{bold (}{ital D}{sup +}{sub {ital s}}{r_arrow}{phi}{ital e}{sup +}{nu})/{ital B} ({ital D}{sup +}{sub {ital s}}{r_arrow}({eta}+{eta}{prime}){ital e}{sup +}{nu}{bold )}=0.60{plus_minus}0.06{plus_minus}0.06, which is similar to the ratio found in nonstrange {ital D} decays. {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.

Re-Introduction of Lower Columbia River Chum Salmon into Duncan Creek, 2003-2004 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Hillson, Todd D. (Washington Department of Fish and Wildlife, Olympia, WA)

2004-09-01

Currently, two methods of reintroduction are being simultaneously evaluated at Duncan Creek. Recolonization is occurring by introducing adult chum salmon from the Lower Gorge (LG) population into Duncan Creek and allowing them to naturally reproduce. The supplementation strategy required adults to be collected and artificially spawned, incubated, reared, and released at the mouth of Duncan Creek. All eggs from the artificial crossings at Washougal Hatchery were incubated and the fry reared to release size at the hatchery. The Duncan Creek chum salmon project was very successful in 2003-04, providing knowledge and experience that will improve program execution in future years. The gear used to collect adult brood stock was changed from tangle nets to beach seines. This increased efficiency and the speed at which adults could be processed in the field, and most likely reduced stress on the adults handled. Certain weaknesses exposed in past seasons still exist and new ones were exposed (e.g. inadequate incubation and rearing space at Washougal Hatchery for any large salvage operation and having to move the rearing troughs outside the raceway in 2004). Egg-to-fry survival rates of 64% and 58% showed that the channels are functioning at the upper end of what can be expected from them. Possibly the most important event this season was the ability to strontium mark and release all naturally-produced fry from the spawning channels. Channel and floodplain modifications reduced the likelihood that floods will damage the channels and negatively impact survival rates.

Search for the flavor changing neutral current B-meson decays B^+arrow μ^+ μ^- K^+ and B^0arrow μ^+ μ^-K^*0 at CDF.

Science.gov (United States)

Erdmann, Wolfram; Speer, Thomas

1997-04-01

We present a search for rare B-meson decays B^+arrow μ^+ μ^- K^+ and B^0arrow μ^+ μ^-K^*0 using data from pbarp collisions at √s = 1.8 TeV recorded with CDF during the 1994 to 95 running period. We set upper limits on BR(B^+arrow μ^+ μ^- K^+) and BR(B^0arrow μ^+ μ^-K^*0). ^ Supported by U.S. DOE DE-AC02-76CH03000. ^*We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Instituto Nazionale di Fisica Nucleare; the Ministry of Education, Science and Culture of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; and the A. P. Sloan Foundation.

Analyses of {ital D}{sup +}{r_arrow}{ital K}{sup 0}{sub {ital S}}{ital K}{sup +} and {ital D}{sup +}{r_arrow}{ital K}{sup 0}{sub {ital S}}{pi}{sup +}

Energy Technology Data Exchange (ETDEWEB)

Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.; Menon, N.; Miller, D.; Shibata, E.; Shipsey, I.; Yurko, M.; Kwak, N. [Purdue University, West Lafayette, Indiana 47907 (United States); Gibbons, L.; Johnson, S.; Kwon, Y.; Roberts, S.; Thorndike, E. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.; Lingel, K.; Marsiske, H.; Perl, M.; Schaffner, S.; Ugolini, D.; Wang, R.; Zhou, X.; Severini, H.; Wappler, F. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Shelkov, V.; Staeck, J.; Stroynowski, R.; Volobouev, I.; Ye, J. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Efimov, A.; Frasconi, F.; Gao, M.; Goldberg, M.; He, D.; Kopp, S.; Moneti, G.; Mountain, R.; Mukhin, Y.; Schuh, S.; Skwarnicki, T.; Stone, S.; Viehhauser, G.; Xing, X. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.; Jain, V.; Marka, S. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Freyberger, A.; Gibaut, D.; Godang, R.; Kinoshita, K.; Lai, I.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L. [Wayne State University, Detroit, Michigan 48202 (United States); Barish, B.; Chadha, M.; Chan, S.; Eigen, G.; Miller, J.; OGrady, C.; Schmidtler, M.; Urheim, J.; Weinstein, A.; Wuerthwein, F. [California Institute of Technology, Pasadena, California 91125 (United States); Asner, D.; Bliss, D.; Brower, W.; Masek, G.; Paar, H.; Sharma, V. [University of California, San Diego, La Jolla, California 92093 (United States); Gronberg, J.; Kutschke, R.; Lange, D.; Menary, S.; Morrison, R.; Nelson, H.; Nelson, T.; Qiao, C.; Richman, J.; Roberts, D.; Ryd, A.; Witherell, M. [University of California, Santa Barbara, California 93106 (United States)

1997-04-01

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we present new measurements of the branching fractions for D{sup +}{r_arrow}K{sub S}K{sup +} and D{sup +}{r_arrow}K{sub S}{pi}{sup +}. These results are combined with other CLEO measurements to extract the ratios of isospin amplitudes and phase shifts for D{r_arrow}KK and D{r_arrow}K{pi}. {copyright} {ital 1997} {ital The American Physical Society}

Measuring effects of voluntary attention: a comparison among predictive arrow, colour, and number cues.

Science.gov (United States)

Olk, Bettina; Tsankova, Elena; Petca, A Raisa; Wilhelm, Adalbert F X

2014-10-01

The Posner cueing paradigm is one of the most widely used paradigms in attention research. Importantly, when employing it, it is critical to understand which type of orienting a cue triggers. It has been suggested that large effects elicited by predictive arrow cues reflect an interaction of involuntary and voluntary orienting. This conclusion is based on comparisons of cueing effects of predictive arrows, nonpredictive arrows (involuntary orienting), and predictive numbers (voluntary orienting). Experiment 1 investigated whether this conclusion is restricted to comparisons with number cues and showed similar results to those of previous studies, but now for comparisons to predictive colour cues, indicating that the earlier conclusion can be generalized. Experiment 2 assessed whether the size of a cueing effect is related to the ease of deriving direction information from a cue, based on the rationale that effects for arrows may be larger, because it may be easier to process direction information given by symbols such as arrows than that given by other cues. Indeed, direction information is derived faster and more accurately from arrows than from colour and number cues in a direction judgement task, and cueing effects are larger for arrows than for the other cues. Importantly though, performance in the two tasks is not correlated. Hence, the large cueing effects of arrows are not a result of the ease of information processing, but of the types of orienting that the arrows elicit.

First Observations of {Upsilon}(1S) {r_arrow} {gamma}{pi}{sup +}{pi}{sup {minus}} and {Upsilon}(1S) {r_arrow} {gamma}{pi}{sup 0}{pi}{sup 0}

Energy Technology Data Exchange (ETDEWEB)

Anastassov, A.; Duboscq, J.E.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Schwarthoff, H.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Richichi, S.J.; Severini, H.; Skubic, P.; Undrus, A. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Chen, S.; Fast, J.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P. [Purdue University, West Lafayette, Indiana 47907 (United States); Glenn, S.; Kwon, Y.; Lyon, A.L.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Savinov, V.; Ugolini, D.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Stroynowski, R.; Ye, J.; Wlodek, T. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Dambasuren, E.; Kopp, S.; Moneti, G.C.; Mountain, R.; Schuh, S.; Skwarnicki, T.; Stone, S.; Titov, A.; Viehhauser, G.; Wang, J.C. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; McLean, K.W.; Marka, S.; Xu, Z. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Godang, R.; Kinoshita, K.; Lai, I.C.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J. [Wayne State University, Detroit, Michigan 48202 (United States); Chan, S.; Eigen, G.; Lipeles, E.; Miller, J.S.; Schmidtler, M.; Shapiro, A.; Sun, W.M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F. [California Institute of Technology, Pasadena, California 91125 (United States); Jaffe, D.E.; Masek, G.; Paar, H.P.; Potter, E.M.; Prell, S.; Sharma, V. [University of California, San Diego, La Jolla, California 92093 (United States); and others

1999-01-01

We report on a study of exclusive radiative decays of the {Upsilon}(1S) resonance collected with the CLEOthinspthinspII detector operating at the Cornell Electron Storage Ring. We present the first observation of the radiative decays {Upsilon}(1S){r_arrow}{gamma}{pi}{sup +}{pi}{sup {minus}} and {Upsilon}(1S){r_arrow}{gamma}{pi}{sup 0}{pi}{sup 0} . For the dipion mass regime m{sub {pi}{pi}}{gt}1.0 GeV , we obtain B({Upsilon}(1S){r_arrow}{gamma}{pi}{sup +}{pi}{sup {minus}})=(6.3{plus_minus}1.2{plus_minus} 1.3){times}10{sup {minus}5} and B({Upsilon}(1S){r_arrow}{gamma}{pi}{sup 0}{pi}{sup 0})=(1.7{plus_minus}0.6{plus_minus} 0.3){times}10{sup {minus}5} . {copyright} {ital 1999} {ital The American Physical Society }

Arrow Lakes Reservoir Fertilization Experiment; Years 4 and 5, Technical Report 2002-2003.

Energy Technology Data Exchange (ETDEWEB)

Schindler, E.

2007-02-01

This report presents the fourth and fifth year (2002 and 2003, respectively) of a five-year fertilization experiment on the Arrow Lakes Reservoir. The goal of the experiment was to increase kokanee populations impacted from hydroelectric development on the Arrow Lakes Reservoir. The impacts resulted in declining stocks of kokanee, a native land-locked sockeye salmon (Oncorhynchus nerka), a key species of the ecosystem. Arrow Lakes Reservoir, located in southeastern British Columbia, has undergone experimental fertilization since 1999. It is modeled after the successful Kootenay Lake fertilization experiment. The amount of fertilizer added in 2002 and 2003 was similar to the previous three years. Phosphorus loading from fertilizer was 52.8 metric tons and nitrogen loading from fertilizer was 268 metric tons. As in previous years, fertilizer additions occurred between the end of April and the beginning of September. Surface temperatures were generally warmer in 2003 than in 2002 in the Arrow Lakes Reservoir from May to September. Local tributary flows to Arrow Lakes Reservoir in 2002 and 2003 were generally less than average, however not as low as had occurred in 2001. Water chemistry parameters in select rivers and streams were similar to previous years results, except for dissolved inorganic nitrogen (DIN) concentrations which were significantly less in 2001, 2002 and 2003. The reduced snow pack in 2001 and 2003 would explain the lower concentrations of DIN. The natural load of DIN to the Arrow system ranged from 7200 tonnes in 1997 to 4500 tonnes in 2003; these results coincide with the decrease in DIN measurements from water samples taken in the reservoir during this period. Water chemistry parameters in the reservoir were similar to previous years of study except for a few exceptions. Seasonal averages of total phosphorus ranged from 2.11 to 7.42 {micro}g/L from 1997 through 2003 in the entire reservoir which were indicative of oligo-mesotrophic conditions

Re-Introduction of Lower Columbia River Chum Salmon into Duncan Creek, 2002-2003 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Hillson, Todd D. (Washington Department of Fish and Wildlife, Olympia, WA)

2003-10-15

spawning refugias, supplementation if necessary and a habitat and fish monitoring and evaluation plan. If chum have been extirpated from previously utilized streams, develop re-introduction plans that utilize appropriate genetic donor stock(s) of LCR chum salmon and integrate habitat improvement and fry-to-adult survival evaluations. Third, reduce extinction risks to the Grays River chum salmon population by randomly capturing adults in the basin for use in a supplementation program and reintroduction into the Chinook River basin. The Duncan Creek project was developed using the same recovery strategy implemented for LCR chum. Biologists with the WDFW and Pacific States Marine Fisheries Commission (PSMFC) identified Duncan Creek as an ideal upriver location below Bonneville Dam for chum re-introduction. It has several attributes that make it a viable location for a re-introduction project: historically chum salmon were present, the creek is low gradient, has numerous springs/seeps, has a low potential for future development and is located close to a donor population of Lower Gorge chum. The Duncan Creek project has two goals: (1) re-introduction of chum into Duncan Creek by providing off channel high-quality spawning and incubation areas, and (2) to simultaneously evaluate natural recolonization and a supplementation strategy where adults are collected and spawned artificially at a hatchery. For supplementation, eggs are incubated and the fry reared at the Washougal Hatchery to be released back into Duncan Creek. The tasks associated with re-establishing a naturally self-sustaining population include: (1) removing mud, sand and organics present in four of the creek branches and replace with gravels expected to provide maximum egg-to-fry survival rates to a depth of at least two feet; (2) armoring the sides of these channels to reduce importation of sediment by fish spawning on the margins; (3) planting native vegetation adjacent to the channels to stabilize the banks, trap

The location-, word-, and arrow-based Simon effects: An ex-Gaussian analysis.

Science.gov (United States)

Luo, Chunming; Proctor, Robert W

2018-04-01

Task-irrelevant spatial information, conveyed by stimulus location, location word, or arrow direction, can influence the response to task-relevant attributes, generating the location-, word-, and arrow-based Simon effects. We examined whether different mechanisms are involved in the generation of these Simon effects by fitting a mathematical ex-Gaussian function to empirical response time (RT) distributions. Specifically, we tested whether which ex-Gaussian parameters (μ, σ, and τ) show Simon effects and whether the location-, word, and arrow-based effects are on different parameters. Results show that the location-based Simon effect occurred on mean RT and μ but not on τ, and a reverse Simon effect occurred on σ. In contrast, a positive word-based Simon effect was obtained on all these measures (including σ), and a positive arrow-based Simon effect was evident on mean RT, σ, and τ but not μ. The arrow-based Simon effect was not different from the word-based Simon effect on τ or σ but was on μ and mean RT. These distinct results on mean RT and ex-Gaussian parameters provide evidence that spatial information conveyed by the various location modes are different in the time-course of activation.

Of arrows and flows. Causality, determination, and specificity in the Central Dogma of molecular biology.

Science.gov (United States)

Fantini, Bernardino

2006-01-01

From its first proposal, the Central Dogma had a graphical form, complete with arrows of different types, and this form quickly became its standard presentation. In different scientific contexts, arrows have different meanings and in this particular case the arrows indicated the flow of information among different macromolecules. A deeper analysis illustrates that the arrows also imply a causal statement, directly connected to the causal role of genetic information. The author suggests a distinction between two different kinds of causal links, defined as 'physical causality' and 'biological determination', both implied in the production of biological specificity.

Duncan Wheeler, Golden Age Drama in Contemporary Spain. The Comedia on Page, Stage and Screen

Directory of Open Access Journals (Sweden)

Alba Carmona

2014-01-01

Full Text Available Review of Duncan Wheeler, Golden Age Drama in Contemporary Spain. The Comedia on Page, Stage and Screen, University of Wales Press, Cardiff, 2012, 295 pp. ISBN: 978-0-7083-2474-5.

New Measurement of {ital B} {r_arrow} {ital D}{sup {asterisk}}{ital {pi}} Branching Fractions

Energy Technology Data Exchange (ETDEWEB)

Brandenburg, G.; Briere, R.A.; Gao, Y.S.; Kim, D.Y.; Wilson, R.; Yamamoto, H. [Harvard University, Cambridge, Massachusetts 02138 (United States); Browder, T.E.; Li, F.; Li, Y.; Rodriguez, J.L. [University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Hans, R.M.; Johnson, E.; Karliner, I.; Marsh, M.A.; Palmer, M.; Selen, M.; Thaler, J.J. [University of Illinois, Champaign-Urbana, Illinois 61801 (United States); Edwards, K.W.; Edwards, K.W. [the Institute of Particle Physics (Canada); Bellerive, A.; Bellerive, A.; Janicek, R.; Janicek, R.; MacFarlane, D.B.; MacFarlane, D.B.; McLean, K.W.; McLean, K.W.; Patel, P.M.; Patel, P.M. [the Institute of Particle Physics (Canada); Sadoff, A.J. [Ithaca College, Ithaca, New York 14850 (United States); Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Darling, C.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N. [University of Kansas, Lawrence, Kansas 66045 (United States); Anderson, S.; Kubota, Y.; Lattery, M.; Lee, S.J.; ONeill, J.J.; Patton, S.; Poling, R.; Riehle, T.; Savinov, V.; Smith, A. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Severini, H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Blinov, S.; Duboscq, J.E.; Fisher, K.D.; Fujino, D.; Fulton, R.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P.; Wood, M. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; Yurko, M. [Purdue University, West Lafayette, Indiana 47907 (United States)

1998-03-01

The decays {Upsilon}(4S){r_arrow}B{ovr B} , followed by B{r_arrow}D{sup {asterisk}}{pi} and D{sup {asterisk}}{r_arrow}D{pi} , permit reconstruction of all kinematic quantities that describe the sequence without reconstruction of the D , with reasonably low backgrounds. Using an integrated e{sup +}e{sup {minus}} luminosity of 3.1 fb{sup {minus}1} accumulated at the {Upsilon}(4S) by the CLEO-II detector, we report measurements of B({ovr B}{sup 0}{r_arrow} D{sup {asterisk}+}{pi}{sup {minus}})=(2.81{plus_minus} 0.11{plus_minus}0.21{plus_minus}0.05){times}10{sup {minus}3} and B(B{sup {minus}}{r_arrow}D{sup {asterisk}0}{pi}{sup {minus}})=(4.34{plus_minus}0.33{plus_minus}0.34{plus_minus}0.1 8){times}10{sup {minus}3} . {copyright} {ital 1998} {ital The American Physical Society}

Battling Arrow's Paradox to Discover Robust Water Management Alternatives

Science.gov (United States)

Kasprzyk, J. R.; Reed, P. M.; Hadka, D.

2013-12-01

This study explores whether or not Arrow's Impossibility Theorem, a theory of social choice, affects the formulation of water resources systems planning problems. The theorem discusses creating an aggregation function for voters choosing from more than three alternatives for society. The Impossibility Theorem is also called Arrow's Paradox, because when trying to add more voters, a single individual's preference will dictate the optimal group decision. In the context of water resources planning, our study is motivated by recent theoretical work that has generalized the insights for Arrow's Paradox to the design of complex engineered systems. In this framing of the paradox, states of society are equivalent to water planning or design alternatives, and the voters are equivalent to multiple planning objectives (e.g. minimizing cost or maximizing performance). Seen from this point of view, multi-objective water planning problems are functionally equivalent to the social choice problem described above. Traditional solutions to such multi-objective problems aggregate multiple performance measures into a single mathematical objective. The Theorem implies that a subset of performance concerns will inadvertently dictate the overall design evaluations in unpredictable ways using such an aggregation. We suggest that instead of aggregation, an explicit many-objective approach to water planning can help overcome the challenges posed by Arrow's Paradox. Many-objective planning explicitly disaggregates measures of performance while supporting the discovery of the planning tradeoffs, employing multiobjective evolutionary algorithms (MOEAs) to find solutions. Using MOEA-based search to address Arrow's Paradox requires that the MOEAs perform robustly with increasing problem complexity, such as adding additional objectives and/or decisions. This study uses comprehensive diagnostic evaluation of MOEA search performance across multiple problem formulations (both aggregated and many

Arrow y Sen: el rescate del individuo y de las instituciones Arrow and Sen: rescuing the individual and institutions

Directory of Open Access Journals (Sweden)

Cante Freddy

1998-12-01

Full Text Available La teoría de la elección social que propone Arrow y Sen es una ruptura con los desarrollos hegemónicos de la microeconomía y de la macroeconomía en dos sentidos: rescata la diversidad de gustos y valores de cada individuo en oposición a los conceptos agregados; además, muestra que la conducta racional es quizás lo menos importante con lo que abre un diálogo con la economía institucional.The theory of social choice proposed by Arrow and Sen breaks with the hegemonic developments of microeconomics and macroeconomics in two senses: it rescues the diversity of tastes and values of each individual as opposed to aggregated concepts, and in addition it shows that rational behavior is perhaps the least important kind, which opens up a dialogue with institutional economics.

References and arrow notation instead of join operation in query languages

Directory of Open Access Journals (Sweden)

Alexandr Savinov

2012-10-01

Full Text Available We study properties of the join operation in query languages and describe some of its major drawbacks. We provide strong arguments against using joins as a main construct for retrieving related data elements in general purpose query languages and argue for using references instead. Since conventional references are quite restrictive when applied to data modeling and query languages, we propose to use generalized references as they are defined in the concept-oriented model (COM. These references are used by two new operations, called projection and de-projection, which are denoted by right and left arrows and therefore this access method is referred to as arrow notation. We demonstrate advantages of the arrow notation in comparison to joins and argue that it makes queries simpler, more natural, easier to understand, and the whole query writing process more productive and less error-prone.

Transfer entropy in physical systems and the arrow of time

Science.gov (United States)

Spinney, Richard E.; Lizier, Joseph T.; Prokopenko, Mikhail

2016-08-01

Recent developments have cemented the realization that many concepts and quantities in thermodynamics and information theory are shared. In this paper, we consider a highly relevant quantity in information theory and complex systems, the transfer entropy, and explore its thermodynamic role by considering the implications of time reversal upon it. By doing so we highlight the role of information dynamics on the nuanced question of observer perspective within thermodynamics by relating the temporal irreversibility in the information dynamics to the configurational (or spatial) resolution of the thermodynamics. We then highlight its role in perhaps the most enduring paradox in modern physics, the manifestation of a (thermodynamic) arrow of time. We find that for systems that process information such as those undergoing feedback, a robust arrow of time can be formulated by considering both the apparent physical behavior which leads to conventional entropy production and the information dynamics which leads to a quantity we call the information theoretic arrow of time. We also offer an interpretation in terms of optimal encoding of observed physical behavior.

First Observation of the Decay {tau}{sup {minus}} {r_arrow} K{sup {asterisk}{minus}}{eta}{nu}{sub {tau}}

Energy Technology Data Exchange (ETDEWEB)

Bishai, M.; Chen, S.; Fast, J.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P. [Purdue University, West Lafayette, Indiana 47907 (United States); Glenn, S.; Kwon, Y.; Lyon, A.L.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Savinov, V.; Ugolini, D.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Stroynowski, R.; Ye, J.; Wlodek, T. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Dambasuren, E.; Kopp, S.; Moneti, G.C.; Mountain, R.; Schuh, S.; Skwarnicki, T.; Stone, S.; Titov, A.; Viehhauser, G.; Wang, J.C. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; McLean, K.W.; Marka, S.; Xu, Z. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Godang, R.; Kinoshita, K.; Lai, I.C.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J. [Wayne State University, Detroit, Michigan 48202 (United States); Chan, S.; Eigen, G.; Lipeles, E.; Miller, J.S.; Schmidtler, M.; Shapiro, A.; Sun, W.M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F. [California Institute of Technology, Pasadena, California 91125 (United States); Jaffe, D.E.; Masek, G.; Paar, H.P.; Potter, E.M.; Prell, S.; Sharma, V. [University of California, San Diego, La Jolla, California 92093 (United States); Asner, D.M.; Gronberg, J.; Hill, T.S.; Lange, D.J.; Morrison, R.J.; Nelson, H.N.; Nelson, T.K.; Roberts, D. [University of California, Santa Barbara, California 93106 (United States); Behrens, B.H.; Ford, W.T.; Gritsan, A.; Krieg, H.; Roy, J.; Smith, J.G. [Univ. of Colorado, Boulder, Colorado 80309-0390 (United States)

1999-01-01

The decay {tau}{sup {minus}}{r_arrow}K{sup {asterisk}{minus}}{eta}{nu}{sub {tau}} has been observed with the CLEOthinspthinspII detector. The K{sup {asterisk}{minus}} is reconstructed in two decay channels, K{sup {asterisk}{minus}}{r_arrow}K{sub S}{pi}{sup {minus}}{r_arrow} {pi}{sup {minus}}{pi}{sup +}{pi}{sup {minus}} and K{sup {asterisk}{minus}}{r_arrow}K{sup {minus}}{pi}{sup 0} . The {eta} is reconstructed from the decay {eta}{r_arrow}{gamma}{gamma} . The measured branching fraction is B({tau}{sup {minus}}{r_arrow}K{sup {asterisk}{minus}} {eta}{nu}{sub {tau}})=(2.9{plus_minus} 0.8{plus_minus}0.4){times}10{sup {minus}4} . We also measure the inclusive branching fractions without requiring the K{sup {asterisk}} resonance, B({tau}{sup {minus}}{r_arrow}K{sub S}{pi}{sup {minus}}{eta}{nu}{sub {tau}})=(1.10 {plus_minus}0.35{plus_minus}0.11){times}10{sup {minus}4} and B({tau}{sup {minus}}{r_arrow}K{sup {minus}}{pi}{sup 0}{eta}{nu}{sub {tau}})=(1.77 {plus_minus}0.56{plus_minus}0.71){times}10{sup {minus}4} . The results indicate that the K{sup {asterisk}{minus}} resonance dominates the K{sub S}{pi}{sup {minus}} mass spectrum. {copyright} {ital 1999} {ital The American Physical Society}

ARTHROSCOPIC MENISCUS REPAIR WITH BIOABSORBABLE ARROWS IN LOCAL ANESTHESIA

Directory of Open Access Journals (Sweden)

Vladimir Senekovič

2004-11-01

Full Text Available Background. The menisci have important function in the knee joint. Because of this it is universally accepted that we have to preserve them as much as possible. After open and partially arthroscopic suture techniques new methods of all-inside meniscus repair with bioabsorbable arrows have been developed in the last decade. The meniscus repair using these arrows represents an easy task for a skilled surgeon. In addition, it can be performed in local anesthesia. We have evaluated the results of the first group of patients who were treated by this method.Methods. From February 2001 to August 2002 15 patients with torn meniscuses have been treated at the Clinical Department for Traumatology, University Medical centre, Ljubljana. We repaired their torn menisci arthroscopically with bioabsorbable arrows in local anesthesia. We divided patients in three groups: a group with isolated meniscus injury, a group with meniscus injury and anterior cruciate ligament injury and a group with associated pathology. Four patients had incarcerated meniscuses. Preoperative Lysholm score in the first group was 38, in the second 42 and in the third group 48. We repaired 12 medial and 3 lateral meniscuses. On average we need 45 minutes for therapeutic arthroscopy. Torn meniscus was fixated with minimum of 1 and maximum of 5 bioabsorbable arrows. All patients except one had the affected knee immobilized with cylinder plaster for 15 days on average.Results. At least three months after the arthroscopic fixation of the torn meniscus in local anesthesia another clinical evaluation was made. In all groups significant improvement was observed regarding the range of motions and absence of pain. Postoperative Lysholm score in the first group was 89, in the second 75 and in the third 71. Average deficit of flexion was 3 degrees while extension was full. One patient complained about the same pain in the joint, he underwent another arthroscopy which showed that the meniscus was

Chronos sickness: digital reality in Duncan Jones’s Source Code

Directory of Open Access Journals (Sweden)

Marcia Tiemy Morita Kawamoto

2017-01-01

Full Text Available http://dx.doi.org/10.5007/2175-8026.2017v70n1p249 The advent of the digital technologies unquestionably affected the cinema. The indexical relation and realistic effect with the photographed world much praised by André Bazin and Roland Barthes is just one of the affected aspects. This article discusses cinema in light of the new digital possibilities, reflecting on Steven Shaviro’s consideration of “how a nonindexical realism might be possible” (63 and how in fact a new kind of reality, a digital one, might emerge in the science fiction film Source Code (2013 by Duncan Jones.

Pycellerator: an arrow-based reaction-like modelling language for biological simulations.

Science.gov (United States)

Shapiro, Bruce E; Mjolsness, Eric

2016-02-15

We introduce Pycellerator, a Python library for reading Cellerator arrow notation from standard text files, conversion to differential equations, generating stand-alone Python solvers, and optionally running and plotting the solutions. All of the original Cellerator arrows, which represent reactions ranging from mass action, Michales-Menten-Henri (MMH) and Gene-Regulation (GRN) to Monod-Wyman-Changeaux (MWC), user defined reactions and enzymatic expansions (KMech), were previously represented with the Mathematica extended character set. These are now typed as reaction-like commands in ASCII text files that are read by Pycellerator, which includes a Python command line interface (CLI), a Python application programming interface (API) and an iPython notebook interface. Cellerator reaction arrows are now input in text files. The arrows are parsed by Pycellerator and translated into differential equations in Python, and Python code is automatically generated to solve the system. Time courses are produced by executing the auto-generated Python code. Users have full freedom to modify the solver and utilize the complete set of standard Python tools. The new libraries are completely independent of the old Cellerator software and do not require Mathematica. All software is available (GPL) from the github repository at https://github.com/biomathman/pycellerator/releases. Details, including installation instructions and a glossary of acronyms and terms, are given in the Supplementary information. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

A Driving Simulator Evaluation of Red Arrows and Flashing Yellow Arrows in Right-Turn Applications : Establishing the Foundation for Future Research

Science.gov (United States)

2017-11-01

Driver understanding of flashing yellow arrow (FYA) indications for left turns has been studied extensively; however, the use of FYA for right-turn applications is an area that needs to be better understood through evaluations focused on actual drive...

Tragic Paradox in Achebe's "Arrow of God"

Science.gov (United States)

Soile, Sola

1976-01-01

Leads into a discussion of Chinua Achebe's "Arrow of God" (1964) from his earlier novel "Things Fall Apart" (1958), because such a comparative approach provides an opportunity to see Achebe's elaboration and development of a subject that is obviously dear to his heart, namely, the trials and tribulations of a dynamic society as…

Atypical Visual Orienting to Gaze- and Arrow-Cues in Adults with High Functioning Autism

Science.gov (United States)

Vlamings, Petra H. J. M.; Stauder, Johannes E. A.; van Son, Ilona A. M.; Mottron, Laurent

2005-01-01

The present study investigates visual orienting to directional cues (arrow or eyes) in adults with high functioning autism (n = 19) and age matched controls (n = 19). A choice reaction time paradigm is used in which eye-or arrow direction correctly (congruent) or incorrectly (incongruent) cues target location. In typically developing participants,…

ARROW (Version 2) Commercial Software Validation and Configuration Control

Energy Technology Data Exchange (ETDEWEB)

HEARD, F.J.

2000-02-10

ARROW (Version 2), a compressible flow piping network modeling and analysis computer program from Applied Flow Technology, was installed for use at the U.S. Department of Energy Hanford Site near Richland, Washington.

ARROW (Version 2) Commercial Software Validation and Configuration Control

International Nuclear Information System (INIS)

HEARD, F.J.

2000-01-01

ARROW (Version 2), a compressible flow piping network modeling and analysis computer program from Applied Flow Technology, was installed for use at the U.S. Department of Energy Hanford Site near Richland, Washington

Logical and historical determination of the Arrow and Sen impossibility theorems

Directory of Open Access Journals (Sweden)

Boričić Branislav

2007-01-01

Full Text Available General classification of mathematical statements divides them into universal, those of the form xA , and existential ЭxA ones. Common formulations of impossibility theorems of K. J. Arrow and A. K. Sen are represented by the statements of the form "there is no x such that A". Bearing in mind logical equivalence of formulae ¬ЭxA and x¬A, we come to the conclusion that the corpus of impossibility theorems, which appears in the theory of social choice, could make a specific and recognizable subclass of universal statements. In this paper, on the basis of the established logical and methodological criteria, we point to a sequence of extremely significant "impossibility theorems", reaching throughout the history of mathematics to the present days and the famous results of Arrow and Sen in field of mathematical economics. We close with specifying the context which makes it possible to formulate the results of Arrow and Sen accurately, presenting a new direct proof of Sen’s result, with no reliance on the notion of minimal liberalism. .

Class Struggle in Contemporary Films: "Hunger Games" vs. "Arrow, The Ultimate Weapon"

Directory of Open Access Journals (Sweden)

Dal Yong Jin

2016-05-01

Full Text Available By critically engaging with Marxist notion of class struggle in contemporary films utilizing the bow and arrow as their signifier, this paper textually analyzes two films in order to find distinctive characteristics of Western movies and non-Western movies. Since the textual analysis becomes very important to understanding how media texts might be used in order to make sense of the world we live in—meaning it is significant to contextualize it within our life and/or society, this paper investigates the ways in which the major themes have developed and what their representations are. It therefore compares and contrasts these movies in terms of their major themes, in particular the ways in which these two films portray capitalism, either internally or externally. It especially examines how the bow and arrow symbolize class struggle either within a country or between countries in order to map out the major differences that the arrows represent.

Does quantum electrodynamics have an arrow of time?

NARCIS (Netherlands)

Atkinson, David

Quantum electrodynamics is a time-symmetric theory that is part of the electroweak interaction, which is invariant under a generalized form of this symmetry, the PCT transformation. The thesis is defended that the arrow of time in electrodynamics is a consequence of the assumption of an initial

The dark arrow of time a scientific novel

CERN Document Server

Villata, Massimo

2017-01-01

This riveting scientific novel combines adventure, love, suspense, magic, pathos, and mystery in a carefully woven plot that is full of unexpected twists and turns. The author is an astrophysicist who has developed an alternative theory, which holds that traveling in time is possible. Time is, in fact, the real protagonist of the novel and of the intrigue surrounding the attempt to seize the secret of Time’s other arrow, the dark arrow normally hidden from us, which points back at our past. The underlying premise is that antimatter is nothing more than common matter moving backwards in time. The justification for this interpretation has been with us for some time, “hiding in plain sight” within Maxwell’s equations, the Lorentz transformations, the CPT theorem of relativistic quantum mechanics, and Feynman diagrams. While the science underlying the narrative is explained whenever necessary, sometimes with the aid of simple mathematical formulas, these scientific asides account for only a small part of ...

Comparison between Duncan and Chang’s EB Model and the Generalized Plasticity Model in the Analysis of a High Earth-Rockfill Dam

Directory of Open Access Journals (Sweden)

Weixin Dong

2013-01-01

Full Text Available Nonlinear elastic model and elastoplastic model are two main kinds of constitutive models of soil, which are widely used in the numerical analyses of soil structure. In this study, Duncan and Chang's EB model and the generalized plasticity model proposed by Pastor, Zienkiewicz, and Chan was discussed and applied to describe the stress-strain relationship of rockfill materials. The two models were validated using the results of triaxial shear tests under different confining pressures. The comparisons between the fittings of models and test data showed that the modified generalized plasticity model is capable of simulating the mechanical behaviours of rockfill materials. The modified generalized plasticity model was implemented into a finite element code to carry out static analyses of a high earth-rockfill dam in China. Nonlinear elastic analyses were also performed with Duncan and Chang's EB model in the same program framework. The comparisons of FEM results and in situ monitoring data showed that the modified PZ-III model can give a better description of deformation of the earth-rockfill dam than Duncan and Chang’s EB model.

Time's arrow: A numerical experiment

Science.gov (United States)

Fowles, G. Richard

1994-04-01

The dependence of time's arrow on initial conditions is illustrated by a numerical example in which plane waves produced by an initial pressure pulse are followed as they are multiply reflected at internal interfaces of a layered medium. Wave interactions at interfaces are shown to be analogous to the retarded and advanced waves of point sources. The model is linear and the calculation is exact and demonstrably time reversible; nevertheless the results show most of the features expected of a macroscopically irreversible system, including the approach to the Maxwell-Boltzmann distribution, ergodicity, and concomitant entropy increase.

The arrows of time a debate in cosmology

CERN Document Server

Mersini-Houghton, Laura

2012-01-01

The concept of time has fascinated humanity throughout history, and remains one of the biggest mysteries in science and philosophy. Yet a deeper understanding of nature at a fundamental level can only be achieved through a comprehension of this strange fourth dimension. Furthermore, the origin of the universe is closely intertwined with the puzzle of time: Did time emerge at the big bang? Why does the direction of time ‘conspire’ with the remarkably ordered initial state of the universe? This book addresses many of the most important questions about time: What is time, and is it fundamental or emergent? Why is there such an arrow of time, closely related to the initial state of the universe, and why do the cosmic, thermodynamic and other arrows agree? These issues are discussed here by leading experts, and each offers a new perspective on the debate. Their contributions delve into the most difficult research topic in physics, also describing the latest cutting edge research on the subject. The book also...

Measurement of the {ovr {ital B}} {r_arrow} {ital Dl}{ovr {nu} } Partial Width and Form Factor Parameters

Energy Technology Data Exchange (ETDEWEB)

Athanas, M.; Avery, P.; Jones, C.D.; Lohner, M.; Prescott, C.; Yelton, J.; Zheng, J. [University of Florida, Gainesville, Florida 32611 (United States); Brandenburg, G.; Briere, R.A.; Ershov, A.; Gao, Y.S.; Kim, D.Y.; Wilson, R.; Yamamoto, H. [Harvard University, Cambridge, Massachusetts 02138 (United States); Browder, T.E.; Li, F.; Li, Y.; Rodriguez, J.L. [University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Hans, R.M.; Johnson, E.; Karliner, I.; Marsh, M.A.; Palmer, M.; Selen, M.; Thaler, J.J. [University of Illinois, Champaign-Urbana, Illinois 61801 (United States); Edwards, K.W.; Edwards, K.W. [the Institute of Particle Physics (Canada); Bellerive, A.; Bellerive, A.; Janicek, R.; Janicek, R.; MacFarlane, D.B.; MacFarlane, D.B.; Patel, P.M.; Patel, P.M. [the Institute of Particle Physics (Canada); Sadoff, A.J. [Ithaca College, Ithaca, New York 14850 (United States); Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Darling, C.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N. [University of Kansas, Lawrence, Kansas 66045 (United States); Anderson, S.; Kubota, Y.; Lee, S.J.; ONeill, J.J.; Patton, S.; Poling, R.; Riehle, T.; Savinov, V.; Smith, A. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Severini, H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Blinov, S.; Duboscq, J.E.; Fujino, D.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; and others

1997-09-01

We have studied the decay {bar B}{r_arrow}Dl{bar {nu}} , where l=e or {mu} . From a fit to the differential decay rate d{Gamma}/dw we measure the rate normalization F{sub D}(1){vert_bar}V{sub cb}{vert_bar} and form factor slope {cflx {rho}}{sup 2}{sub D} , and, using measured values of {tau}{sub B} , find {Gamma}({bar B}{r_arrow}Dl{bar {nu}}) = (12.0{plus_minus}0.9{plus_minus}2.1) ns{sup {minus}1}. The resulting branching fractions are B({bar B}{sup 0}{r_arrow}D{sup +}l{sup {minus}}{bar {nu}})=(1.87{plus_minus}0.15{plus_minus} 0.32){percent} and B(B{sup {minus}}{r_arrow}D{sup 0} l{sup {minus}}{bar {nu}})=(1.94{plus_minus}0.15{plus_minus}0.34){percent} . The form factor parameters are in agreement with those measured in {bar B}{r_arrow}D{sup *}l{bar {nu}} decays, as predicted by heavy quark effective theory. {copyright} {ital 1997} {ital The American Physical Society}

Recent developments in the field of arrow and dart poisons.

Science.gov (United States)

Philippe, Geneviève; Angenot, Luc

2005-08-22

Arrow and dart poisons, considered as conventional natural sources for future drug discovery, have already provided numerous biologically active molecules used as drugs in therapeutic applications or in pharmacological research. Plants containing alkaloids or cardiotonic glycosides have generally been the main ingredients responsible for the efficacy of these poisons, although some animals, such as frogs, have also been employed. This paper, without being exhaustive, reports the greater strides made during the past 15 years in the understanding of the chemical nature and biological properties of arrow and dart poison constituents. Examples both of promising biological properties shown by these molecules and of crucial discoveries achieved by their use as pharmacological tools are given. Further studies of these toxic principles are likely to enable scientists to find new valuable lead compounds, useful in many fields of research, like oncology, inflammation and infectious diseases.

Stochasticity, decoherence and an arrow of time from the ...

Indian Academy of Sciences (India)

Certain intriguing consequences of the discreteness of time on the time evolution of dynamical systems are discussed. In the discrete-time classical mechanics proposed here, there is an arrow of time that follows from the fact that the replacement of the time derivative by the backward difference operator alone can preserve ...

Re-Introduction of Lower Columbia River Chum Salmon into Duncan Creek, 2001-2002 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Hillson, Todd D. (Washington Department of Wildlife, Olympia, WA)

2002-10-01

Duncan Creek project has two goals: (1) re-introduction of chum into Duncan Creek by providing off channel high quality spawning and incubation areas and (2) to simultaneously evaluate natural re-colonization and a supplementation strategy where adults are collected and spawned artificially at a hatchery. The eggs from these artificial crossings are then either incubated at Duncan Creek or incubated and the fry reared at the hatchery to be released back into Duncan Creek. Tasks associated with the first goal include: (1) removing mud, sand and organics present in four of the creek branches and replace with gravels expected to provide maximum egg-to-fry survival rates to a depth of at least two feet; (2) armoring the sides of these channels to reduce importation of sediment by fish spawning on the margins; (3) planting native vegetation adjacent to these channels to stabilize the banks, trap silt and provide shade; (4) annual sampling of gravel in the spawning channels to detect changes in gravel composition and sedimentation levels.

Recognition of Damaged Arrow-Road Markings by Visible Light Camera Sensor Based on Convolutional Neural Network

Directory of Open Access Journals (Sweden)

Husan Vokhidov

2016-12-01

Full Text Available Automobile driver information as displayed on marked road signs indicates the state of the road, traffic conditions, proximity to schools, etc. These signs are important to insure the safety of the driver and pedestrians. They are also important input to the automated advanced driver assistance system (ADAS, installed in many automobiles. Over time, the arrow-road markings may be eroded or otherwise damaged by automobile contact, making it difficult for the driver to correctly identify the marking. Failure to properly identify an arrow-road marker creates a dangerous situation that may result in traffic accidents or pedestrian injury. Very little research exists that studies the problem of automated identification of damaged arrow-road marking painted on the road. In this study, we propose a method that uses a convolutional neural network (CNN to recognize six types of arrow-road markings, possibly damaged, by visible light camera sensor. Experimental results with six databases of Road marking dataset, KITTI dataset, Málaga dataset 2009, Málaga urban dataset, Naver street view dataset, and Road/Lane detection evaluation 2013 dataset, show that our method outperforms conventional methods.

Recognition of Damaged Arrow-Road Markings by Visible Light Camera Sensor Based on Convolutional Neural Network.

Science.gov (United States)

Vokhidov, Husan; Hong, Hyung Gil; Kang, Jin Kyu; Hoang, Toan Minh; Park, Kang Ryoung

2016-12-16

Automobile driver information as displayed on marked road signs indicates the state of the road, traffic conditions, proximity to schools, etc. These signs are important to insure the safety of the driver and pedestrians. They are also important input to the automated advanced driver assistance system (ADAS), installed in many automobiles. Over time, the arrow-road markings may be eroded or otherwise damaged by automobile contact, making it difficult for the driver to correctly identify the marking. Failure to properly identify an arrow-road marker creates a dangerous situation that may result in traffic accidents or pedestrian injury. Very little research exists that studies the problem of automated identification of damaged arrow-road marking painted on the road. In this study, we propose a method that uses a convolutional neural network (CNN) to recognize six types of arrow-road markings, possibly damaged, by visible light camera sensor. Experimental results with six databases of Road marking dataset, KITTI dataset, Málaga dataset 2009, Málaga urban dataset, Naver street view dataset, and Road/Lane detection evaluation 2013 dataset, show that our method outperforms conventional methods.

Recognition of Damaged Arrow-Road Markings by Visible Light Camera Sensor Based on Convolutional Neural Network

Science.gov (United States)

Vokhidov, Husan; Hong, Hyung Gil; Kang, Jin Kyu; Hoang, Toan Minh; Park, Kang Ryoung

2016-01-01

Automobile driver information as displayed on marked road signs indicates the state of the road, traffic conditions, proximity to schools, etc. These signs are important to insure the safety of the driver and pedestrians. They are also important input to the automated advanced driver assistance system (ADAS), installed in many automobiles. Over time, the arrow-road markings may be eroded or otherwise damaged by automobile contact, making it difficult for the driver to correctly identify the marking. Failure to properly identify an arrow-road marker creates a dangerous situation that may result in traffic accidents or pedestrian injury. Very little research exists that studies the problem of automated identification of damaged arrow-road marking painted on the road. In this study, we propose a method that uses a convolutional neural network (CNN) to recognize six types of arrow-road markings, possibly damaged, by visible light camera sensor. Experimental results with six databases of Road marking dataset, KITTI dataset, Málaga dataset 2009, Málaga urban dataset, Naver street view dataset, and Road/Lane detection evaluation 2013 dataset, show that our method outperforms conventional methods. PMID:27999301

First measurement of the rate for the inclusive radiative penguin decay {ital b}{r_arrow}{ital s}{gamma}

Energy Technology Data Exchange (ETDEWEB)

Alam, M.S.; Kim, I.J.; Ling, Z.; Mahmood, A.H.; O`Neill, J.J.; Severini, H.; Sun, C.R.; Wappler, F.; Crawford, G.; Daubenmier, C.M.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; White, C.; Wolf, A.; Zoeller, M.M.; Butler, F.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; McIlwain, R.L.; Miao, T.; Miller, D.H.; Modesitt, M.; Payne, D.; Shibata, E.I.; Shipsey, I.P.J.; Wang, P.N.; Battle, M.; Ernst, J.; Gibbons, L.; Kwon, Y.; Roberts, S.; Thorndike, E.H.; Wang, C.H.; Coan, T.; Dominick, J.; Fadeyev, V.; Korolkov, I.; Lambrecht, M.; Sanghera, S.; Shelkov, V.; Skwarnicki, T.; Stroynowski, R.; Volobouev, I.; Wei, G.; Artuso, M.; Gao, M.; Goldberg, M.; He, D.; Horwitz, N.; Moneti, G.C.; Mountain, R.; Muheim, F.; Mukhin, Y.; Playfer, S.; Rozen, Y.; Stone, S.; Xing, X.; Zhu, G.; Bartelt, J.; Csorna, S.E.; Egyed, Z.; Jain, V.; Gibaut, D.; Kinoshita, K.; Pomianowski, P.; Barish, B.; Chadha, M.; Chan, S.; Cowen, D.F.; Eigen, G.; Miller, J.S.; O`Grady, C.; Urheim, J.; Weinstein, A.J.; Athanas, M.; Brower, W.; Masek, G.; Paar, H.P.; Gronberg, J.; Korte, C.M.; Kutschke, R.; Menary, S.; Morrison, R.J.; Nakanishi, S.; Nelson, H.N.; Nelson, T.K.; Qiao, C.; Richman, J.D.; Ryd, A.; Sperka, D.; Tajima, H.; Witherell, M.S.; Balest, R.; Cho, K.; Ford, W.T.; Johnson, D.R.; Lingel, K.; Lohner, M.; Rankin, P.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berkelman, K.; Bloom, K.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Drell, P.S.; Dumas, D.J.; Ehrlich, R.; Gaidarev, P.; Garcia-Sciveres, M.; Geiser, B.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Patterson, J.R.; Peterson, D.; Riley, D.; Salman, S.; Sapper, M.; Wuerthwein, F.; Avery, P.; Freyberger, A.; Rodriguez, J.; (CLEO Co...

1995-04-10

We have measured the inclusive {ital b}{r_arrow}{ital s}{gamma} branching ratio to be (2.32{plus_minus}0.57{plus_minus}0.35){times}10{sup {minus}4}, where the first error is statistical and the second is systematic. Upper and lower limits on the branching ratio, each at 95% C.L., are {ital B}({ital b}{r_arrow}{ital s}{gamma}){lt}4.2{times}10{sup {minus}4} and {ital B}({ital b}{r_arrow}{ital s}{gamma}){gt}1.0{times}10{sup {minus}4}. These limits restrict the parameters of extensions of the standard model.

Elliptical Orbit [arrow right] 1/r[superscript 2] Force

Science.gov (United States)

Prentis, Jeffrey; Fulton, Bryan; Hesse, Carol; Mazzino, Laura

2007-01-01

Newton's proof of the connection between elliptical orbits and inverse-square forces ranks among the "top ten" calculations in the history of science. This time-honored calculation is a highlight in an upper-level mechanics course. It would be worthwhile if students in introductory physics could prove the relation "elliptical orbit" [arrow right]…

Reintroduction of Lower Columbia River Chum Salmon into Duncan Creek, 2007 Annual Report.

Energy Technology Data Exchange (ETDEWEB)

Hillson, Todd D. [Washington Department of Fish and Wildlife

2009-06-12

Bonneville Dam and those spawning in Hamilton and Hardy creeks. Response to the federal ESA listing has been primarily through direct-recovery actions: reducing harvest, hatchery supplementation using local broodstock for populations at catastrophic risk, habitat restoration (including construction of spawning channels) and flow agreements to protect spawning and rearing areas. Both state and federal agencies have built controlled spawning areas. In 1998, the Washington Department of Fish and Wildlife (WDFW) began a chum salmon supplementation program using native stock on the Grays River. This program was expanded during 1999 - 2001 to include reintroduction into the Chinook River using eggs from the Grays River Supplementation Program. These eggs are incubated at the Grays River Hatchery, reared to release size at the Sea Resources Hatchery on the Chinook River, and the fry are released at the mouth of the Chinook River. Native steelhead, chum, and coho salmon are present in Duncan Creek, and are recognized as subpopulations of the Lower Gorge population, and are focal species in the Lower Columbia Fish Recovery Board (LCFRB) plan. Steelhead, chum and coho salmon that spawn in Duncan Creek are listed as Threatened under the ESA. Duncan Creek is classified by the LCFRB plan as a watershed for intensive monitoring (LCFRB 2004). This project was identified in the 2004 Federal Columbia River Power System (FCRPS) revised Biological Opinion (revised BiOp) to increase survival of chum salmon, 'BPA will continue to fund the program to re-introduce Columbia River chum salmon into Duncan Creek as long as NOAA Fisheries determines it to be an essential and effective contribution to reducing the risk of extinction for this ESU'. (USACE et al. 2004, page 85-86). The Governors Forum on Monitoring and Salmon Recovery and Watershed Health recommends one major population from each ESU have adult and juvenile monitoring. Duncan Creek chum salmon are identified in this plan to be

Though Arrow Says It’s Impossible, It Happens Everyday

OpenAIRE

Mohammad Gani

2004-01-01

Arrow’s Impossibility Theorem shows that transitive social preference is impossible. This note shows that in the general case of exchange, social preference need not be transitive. Indeed, it shows that social preference must be non-transitive to allow gainful exchange to maximize social welfare. Thus though Arrow says it is impossible, it actually happens everyday and everywhere.

Observation of the Cabibbo-suppressed charmed baryon decay {Lambda}{sub {ital c}}{sup +}{r_arrow}{ital p}{phi}

Energy Technology Data Exchange (ETDEWEB)

Alexander, J.P.; Bebek, C.; Berger, B.E.; Berkelman, K.; Bloom, K.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Dickson, M.; Drell, P.S.; Dumas, D.J.; Ehrlich, R.; Elia, R.; Gaidarev, P.; Garcia-Sciveres, M.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Lee, T.; Liu, Y.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Avery, P.; Freyberger, A.; Lingel, K.; Prescott, C.; Rodriguez, J.; Yang, S.; Yelton, J.; Brandenburg, G.; Cinabro, D.; Liu, T.; Saulnier, M.; Wilson, R.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Palmer, M.; Selen, M.; Thaler, J.J.; Edwards, K.W.; McLean, K.W.; Ogg, M.; Bellerive, A.; Britton, D.I.; Hyatt, E.R.; Janicek, R.; MacFarlane, D.B.; Patel, P.M.; Spaan, B.; Sadoff, A.J.; Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Copty, N.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N.; Kubota, Y.; Lattery, M.; Momayezi, M.; Nelson, J.K.; Patton, S.; Poling, R.; Savinov, V.; Schrenk, S.; Wang, R.; Alam, M.S.; Kim, I.J.; Ling, Z.; Mahmood, A.H.; ONeill, J.J.; Severini, H.; Sun, C.R.; Wappler, F.; Crawford, G.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; White, C.; Wolf, A.; Zoeller, M.M.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Miao, T.; Miller, D.H.; Modesitt, M.; Shibata, E.I.; Shipsey, I.P.; Wang, P.N.; Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H.; Coan, T.E.; Dominick, J.; Fadeyev, V.; Korolkov, I.; Lambrecht, M.; Sanghera, S.; Shelkov, V.; Skwarnicki, T.; Stroynowski, R.; Volobouev, I.; Wei, G.; Artuso, M.; Gao, M.; Goldberg, M.; He, D.; Horwitz, N.; Kopp, S.; Moneti, G.C.; Mountain, R.; Muheim, F.; Mukhin, Y.; Playfer, S.

1996-02-01

We report the observation of the Cabibbo-suppressed decays {Lambda}{sub {ital c}}{sup +}{r_arrow}{ital pK{sup {minus}}K{sup +}} and {Lambda}{sub {ital c}}{sup +}{r_arrow}{ital p}{phi} using data collected with the CLEO II detector at CESR. The latter mode, observed for the first time with significant statistics, is of interest as a test of color suppression in charm decays. We have determined the branching ratios for these modes relative to {Lambda}{sub {ital c}}{sup +}{r_arrow}{ital pK{sup {minus}}}{pi}{sup +} and compared our results with theory. {copyright} {ital 1996 The American Physical Society.}

MRI of menisci repaired with bioabsorbable arrows

International Nuclear Information System (INIS)

Mustonen, Antti O.T.; Kiuru, Martti; Koskinen, Seppo K.; Tielinen, Laura; Lindahl, Jan; Hirvensalo, Eero

2006-01-01

To analyze with conventional magnetic resonance imaging (MRI) the signal appearance of menisci repaired with bioabsorbable arrows. Forty-four patients with 47 meniscal tears treated with bioabsorbable arrows underwent follow-up conventional MRI examination. The time interval between the surgery and MRI varied from 5 to 67 months (mean 26 months). Twenty-six patients also had concurrent repair of torn anterior cruciate ligament. The following grades were used to classify meniscal signal intensity: (a) G0; low signal intensity on all sequences and regular configuration in every plane, (b) G1; increased signal intensity within the meniscus, not extending to the meniscal surface, (c) G2; increased signal intensity linear in shape, which may or may not communicate with the capsular margin of the meniscus, without extending to the meniscal surface, and (d) G3; increased signal intensity extending to the meniscal surface. Thirteen menisci (27.5%) had normal signal intensity, 13 menisci (27.5%) Grade 1 signal intensity, 9 menisci (19%) Grade 2 signal intensity and 12 menisci (26%) Grade 3 signal intensity. The time difference between operation and MRI was statistically significant between the G0 (36 months) and G3 groups (14 months; P=0.0288). There was no statistical significance in different grades between medial and lateral meniscus or between patients with operated or intact ACL. On physical examination sixteen patients reported slight symptoms, seen evenly in each group. (orig.)

The generic nature of the global and non-entropic arrow of time and the dual role of the energy-momentum tensor

Energy Technology Data Exchange (ETDEWEB)

Castagnino, Mario [CONICET-Instituto de AstronomIa y FIsica del Espacio, Casilla de Correos 67, Sucursal 28, 1428 Buenos Aires (Argentina); Lombardi, Olimpia [CONICET-Universidad Autonoma de Madrid, Ctra. Colmenar Km 15, 28049 Madrid (Spain)

2004-04-16

In this paper we adopt a generic, global and non-entropic approach to the problem of the arrow of time, according to which the arrow of time is a generic, intrinsic and geometrical property of spacetime. We demonstrate that the arrow of time so defined is generic in the sense that any spacetime with physically reasonable properties (e.g. time-orientability and global time) will be endowed with an arrow of time. The only exceptions are very special cases belonging to a subset of zero measure of the set of all possible spacetimes. We also show the dual role played by the energy-momentum tensor in the context of our approach. On one hand, the energy-momentum tensor is the intermediate step that permits us to turn the geometrical time-asymmetry of the universe into a local arrow of time manifested as a time-asymmetric energy flow. On the other hand, the energy-momentum tensor supplies the basis for deducing the time-asymmetry of quantum field theory, posed as an axiom in this theory.

Nuclear Belief Systems and Individual Policy-Makers: Duncan Sandys, Unmanned Weaponry, and the Impossibility of Defence

OpenAIRE

Betts, Lewis

2014-01-01

This thesis attempts to explore the influence that Duncan Sandys' experiences of the Second World War had on his policy preferences, and policy-making, in relation to British defence policy during his years in government. This is a significant period in British nuclear policy which began with thermonuclear weaponry being placed ostentatiously at the centre of British defence planning in the 1957 Defence White Paper, and ended with the British acquiring the latest American nuclear weapon techn...

Arrow injuries in North Eastern Nigeria | Na'Aya | Port Harcourt ...

African Journals Online (AJOL)

Background: Arrow injuries are common presentation at the Federal Medical Centre (FMC), Nguru, North East Nigeria. The injuries are mostly unreported and there is neither a policy nor an action plan to curb their incidence. Aim: To establish an accurate data base for this clinical entity in this part of Nigeria and suggest ...

What remains of the Arrow oil?

International Nuclear Information System (INIS)

Sergy, G.; Owens, E.

1993-01-01

In February 1970, the tanker Arrow became grounded 6.5 km off the north shore of Chedabucto Bay, Nova Scotia, and nearly 72,000 bbl of Bunker C fuel oil were released from the vessel during its subsequent breakup and sinking. The oil was washed ashore in various degrees over an estimated 305 km of the bay's 604-km shoreline, of which only 48 km were cleaned. In addition, the tanker Kurdistan broke in two in pack ice in March 1979 in the Cabot Strait area, spilling ca 54,000 bbl of Bunker C, some of which was later found at 16 locations along the northeast and east shorelines of Chedabucto Bay. In summer 1992, a systematic ground survey of the bay's shorelines was conducted using Environment Canada Shoreline Cleanup Assessment Team (SCAT) procedures. Standard observations were made of oil distribution and width, thickness, and character of the oil residues in 419 coastal segments. Results from the survey are summarized. Oil was found to be present on 13.3 km of the shoreline, with heavy oiling restricted to 1.3 km primarily in the areas of Black Duck Cove and Lennox Passage. Some of this residual oil was identified as coming from the Arrow. Natural weathering processes account for removal of most of the spilled oil from the bay. Oil remaining on the shore was found in areas outside of the zone of physical wave action, in areas of nearshore mixing where fine sediments are not present to weather the oil through biophysical processes, or in crusts formed by oil weathered on the surface. The systematic description of oiled shorelines using the SCAT methodology proved very successful, even for such an old spill. 6 refs

Frequency-modulation transient absorption spectrum of the HCCl A 1A double-prime(0,0,0)left-arrow X 1A'(0,0,0) transition

International Nuclear Information System (INIS)

Chang, B.; Sears, T.J.

1995-01-01

The rotationally resolved spectrum of the HCCl A 1 A double-prime(0,0,0)left-arrow X 1 A'(0,0,0) transition between 12 230 and 12 410 cm -1 was obtained for the first time at Doppler-limited resolution using a frequency-modulation (FM) transient absorption technique. Five major subbands (K a =0 left-arrow 1, 1 left-arrow 0, 1 left-arrow 2, 2 left-arrow 1, and 2 left-arrow 3) of HC 35 Cl and one subband (K a =0 left-arrow 1) of HC 37 Cl were observed and assigned. In addition, the forbidden subband (K a =0 left-arrow 0) of HC 35 Cl was also observed. Thus far, we have assigned most (more than 70%) of the strong lines. The analysis of these subbands determines the geometry for the HCCl A(0,0,0) level: angle HCCl=134.7 degree and R C-Cl =1.623 A while R C-H is fixed at the corresponding value of CH 2 . The height of the barrier to linearity was found to be approximately 2170 cm -1 above the vibrationless level of the A state. The rotational structure of this spectrum shows irregular perturbations. Both random and J-dependent (anomalous K-type doubling) effects were observed. As in methylene, the perturbations most likely arise from Renner--Teller effect between the two singlet states in combination with spin--orbit coupling between the singlet and triplet states

Measurement of the ratio of branching fractions {ital B}({ital D}{sup 0}{r_arrow}{pi}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}})/{ital B}({ital D}{sup 0}{r_arrow}{ital K}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}})

Energy Technology Data Exchange (ETDEWEB)

Butler, F.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; McIlwain, R.L.; Miao, T.; Miller, D.H.; Modesitt, M.; Payne, D.; Shibata, E.I.; Shipsey, I.P.J.; Wang, P.N.; Gibbons, L.; Kwon, Y.; Roberts, S.; Thorndike, E.H.; Coan, T.E.; Dominick, J.; Fadeyev, V.; Korolkov, I.; Lambrecht, M.; Sanghera, S.; Shelkov, V.; Skwarnicki, T.; Stroynowski, R.; Volobouev, I.; Wei, G.; Artuso, M.; Gao, M.; Goldberg, M.; He, D.; Horwitz, N.; Moneti, G.C.; Mountain, R.; Muheim, F.; Mukhin, Y.; Playfer, S.; Rozen, Y.; Stone, S.; Xing, X.; Zhu, G.; Bartelt, J.; Csorna, S.E.; Egyed, Z.; Jain, V.; Gibaut, D.; Kinoshita, K.; Pomianowski, P.; Barish, B.; Chadha, M.; Chan, S.; Cowen, D.F.; Eigen, G.; Miller, J.S.; O`Grady, C.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F.; Asner, D.M.; Athanas, M.; Bliss, D.W.; Brower, W.S.; Masek, G.; Paar, H.P.; Gronberg, J.; Korte, C.M.; Kutschke, R.; Menary, S.; Morrison, R.J.; Nakanishi, S.; Nelson, H.N.; Nelson, T.K.; Qiao, C.; Richman, J.D.; Roberts, D.; Ryd, A.; Tajima, H.; Witherell, M.S.; Balest, R.; Cho, K.; Ford, W.T.; Lohner, M.; Park, H.; Rankin, P.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berger, B.E.; Berkelman, K.; Bloom, K.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Dickson, M.; Drell, P.S.; Dumas, D.J.; Ehrlich, R.; Elia, R.; Gaidarev, P.; Garcia-Sciveres, M.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Liu, Y.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Avery, P.; Freyberger, A.; Lingel, K.; Rodriguez, J.; Yang, S.; Yelton, J.; Brandenburg, G.; Cinabro, D.; Liu, T.; Saulnier, M.; Wilson, R.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Palmer, M.; Selen, M.; Thaler, J.J.; Edwards, K.W.; McLean, K.W.; (CLEO Collabor...

1995-09-01

Using 3.0 fb{sup {minus}1} of data collected with the CLEO-II detector, we study the Cabibbo-suppressed decay {ital D}{sup 0}{r_arrow}{pi}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}}. The ratio of the branching fractions {ital B}({ital D}{sup 0}{r_arrow}{pi}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}})/{ital B}({ital D}{sup 0}{r_arrow}{ital K}{sup {minus}}{ital e}{sup +}{nu}{sub {ital e}}) is measured to be (10.3{plus_minus}3.9{plus_minus}1.3)%, corresponding to an upper limit of 15.6% at the 90% confidence level.

Isospin corrections to charmless semileptonic {ital B}{r_arrow}{ital V} transitions

Energy Technology Data Exchange (ETDEWEB)

Diaz-Cruz, J.L. [Instituto de Fisica, Universidad Autonoma de Puebla, Apartado Postal J-48, 72500 Puebla, Puebla (Mexico); Lopez Castro, G. [Departamento de Fisica, Cinvestav del IPN, Apartado Postal 14-740, 07000 Mexico, D.F. (Mexico); Munoz, J.H. [Departamento de Fisica, Cinvestav del IPN, Apartado Postal 14-740, 07000 Mexico, D.F. (Mexico)]|[Departamento de Fisica, Universidad del Tolima, A. A. 546, Ibague (Colombia)

1996-08-01

We compute isospin corrections to the charmless semileptonic {ital B}{r_arrow}{ital V} transitions arising from {rho}-{omega} mixing and discuss its relevance in the determination of {ital V}{sub {ital ub}}. {copyright} {ital 1996 The American Physical Society.}

La cultura oral de los hojalateros nómadas escoceses: las recolecciones de Duncan Williamson

OpenAIRE

Cardeña Contreras, Javier

2014-01-01

Esta tesis doctoral aborda principalmente la traducción y el estudio de un corpus de cuentos y leyendas de los hojalateros nómadas escoceses, y en especial de los relatos que recopiló y almacenó en su memoria el narrador hojalatero Duncan Williamson. La extraordinaria colección de tipos cuentísticos y motivos folclóricos de esta tradición y su relación con los usos y costumbres de los hojalateros escoceses han contribuido a que este trabajo también contenga un estudio sociológico de la cultur...

Investigating Hemispheric Lateralization of Reflexive Attention to Gaze and Arrow Cues

Science.gov (United States)

Marotta, Andrea; Lupianez, Juan; Casagrande, Maria

2012-01-01

Recent studies have demonstrated that central cues, such as eyes and arrows, reflexively trigger attentional shifts. However, it is not clear whether the attentional mechanisms induced by these two cues are similar or rather differ in some important way. We investigated hemispheric lateralization of the orienting effects induced by the two cue…

Study of gluon versus quark fragmentation in {Upsilon}{r_arrow}gg{gamma} and e{sup +}e{sup {minus}}{r_arrow}q{bar q}{gamma} events at {radical}(s)=10 GeV

Energy Technology Data Exchange (ETDEWEB)

Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Severini, H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Blinov, S.; Duboscq, J.E.; Fujino, D.; Fulton, R.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P.; Wood, M. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; Yurko, M. [Purdue University, West Lafayette, Indiana 47907 (United States); Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Schaffner, S.F.; Ugolini, D.; Wang, R.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Shelkov, V.; Staeck, J.; Stroynowski, R.; Volobouev, I.; Ye, J. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Efimov, A.; Frasconi, F.; Gao, M.; Goldberg, M.; He, D.; Kopp, S.; Moneti, G.C.; Mountain, R.; Mukhin, Y.; Schuh, S.; Skwarnicki, T.; Stone, S.; Viehhauser, G.; Xing, X. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; Jain, V.; Marka, S. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Freyberger, A.; Gibaut, D.; Godang, R.; Kinoshita, K.; Lai, I.C.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P. [Wayne State University, Detroit, Michigan 48202 (United States); Barish, B.; Chadha, M.; and others

1997-07-01

Using data collected with the CLEO II detector at the Cornell Electron Storage Ring, we determine the ratio R{sub chrg} for the mean charged multiplicity observed in {Upsilon}(1S){r_arrow}gg{gamma} events, {l_angle}n{sub gluon}{sup {plus_minus}}{r_angle}, to the mean charged multiplicity observed in e{sup +}e{sup {minus}}{r_arrow}q{bar q}{gamma} events, {l_angle}n{sub quark}{sup {plus_minus}}{r_angle}. We find R{sub chrg}{equivalent_to}{l_angle}n{sub gluon}{sup {plus_minus}}{r_angle}/{l_angle}n{sub quark}{sup {plus_minus}}{r_angle}=1.04 {plus_minus}0.02(stat){plus_minus}0.05(syst) for jet-jet masses less than 7 GeV. {copyright} {ital 1997} {ital The American Physical Society}

Time arrow is influenced by the dark energy.

Science.gov (United States)

Allahverdyan, A E; Gurzadyan, V G

2016-05-01

The arrow of time and the accelerated expansion are two fundamental empirical facts of the universe. We advance the viewpoint that the dark energy (positive cosmological constant) accelerating the expansion of the universe also supports the time asymmetry. It is related to the decay of metastable states under generic perturbations, as we show on example of a microcanonical ensemble. These states will not be metastable without dark energy. The latter also ensures a hyperbolic motion leading to dynamic entropy production with the rate determined by the cosmological constant.

La génesis de la Economía de la Salud en Kenneth Arrow (1963

Directory of Open Access Journals (Sweden)

Jairo Restrepo

2016-01-01

Full Text Available Kenneth J. Arrow es uno de los economistas más destacados del siglo XX. Sus preocupaciones sobre el equilibrio competitivo y la optimalidad bajo condiciones de incertidumbre lo llevaron a publicar en 1963 el artículo “Uncertainty and the welfare economics of medical care”, reconocido como la génesis de la Economía de la Salud. En este ensayo se rinde un homenaje a esta obra, develando el plan intelectual para el análisis de bienestar de las prestaciones médicas, discutiendo la vigencia de los planteamientos originales y destacando sus principales implicaciones en cuanto a los temas objeto de análisis y discusión. La tesis central de Arrow sobre la imposibilidad del mercado para alcanzar una asignación eficiente sigue vigente debido, especialmente, a la incertidumbre respecto a la incidencia de enfermedades. Además del debate sobre Estado-mercado, a partir de Arrow se discuten las implicaciones de asuntos como la información asimétrica, el riesgo moral y las normas sociales.

Measurements of the decays {tau}{sup {minus}}{r_arrow}{ital h}{sup {minus}}{ital h}{sup +}{ital h}{sup {minus}}{nu}{sub {tau}} and {tau}{sup {minus}}{r_arrow}{ital h}{sup {minus}}{ital h}{sup +}{ital h}{sup {minus}}{pi}{sup 0}{nu}{sub {tau}}

Energy Technology Data Exchange (ETDEWEB)

Balest, R.; Cho, K.; Ford, W.T.; Lohner, M.; Park, H.; Rankin, P.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berger, B.E.; Berkelman, K.; Bloom, K.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Dickson, M.; Drell, P.S.; Dumas, D.J.; Ehrlich, R.; Elia, R.; Gaidarev, P.; Garcia-Sciveres, M.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Lee, T.; Liu, Y.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Avery, P.; Freyberger, A.; Lingel, K.; Prescott, C.; Rodriguez, J.; Yang, S.; Yelton, J.; Brandenburg, G.; Cinabro, D.; Liu, T.; Saulnier, M.; Wilson, R.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Palmer, M.; Selen, M.; Thaler, J.J.; Edwards, K.W.; McLean, K.W.; Ogg, M.; Bellerive, A.; Britton, D.I.; Hyatt, E.R.F.; Janicek, R.; MacFarlane, D.B.; Patel, P.M.; Spaan, B.; Sadoff, A.J.; Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Copty, N.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N.; Kubota, Y.; Lattery, M.; Momayezi, M.; Nelson, J.K.; Patton, S.; Poling, R.; Savinov, V.; Schrenk, S.; Wang, R.; Alam, M.S.; Kim, I.J.; Ling, Z.; Mahmood, A.H.; O`Neill, J.J.; Severini, H.; Sun, C.R.; Wappler, F.; Crawford, G.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; White, C.; Wolf, A.; Zoeller, M.M.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Miao, T.; Miller, D.H.; Modesitt, M.; Shibata, E.I.; Shipsey, I.P.J.; Wang, P.N.; Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H.; Coan, T.E.; Dominick, J.; Fadeyev, V.; Korolkov, I.; Lambrecht, M.; Sanghera, S.; Shelkov, V.; Skwarnicki, T.; Stroynowski, R.; Volobouev, I.; Wei, G.; Artuso, M.; Gao, M.; Goldberg, M.; He, D.; (CLEO Colla...

1995-11-20

We use a data sample of 2.8{times}10{sup 6} produced {tau}-pair events, obtained with the CLEO II detector, to measure {ital B}{bold (}{tau}{sup {minus}}{r_arrow}{ital h}{sup {minus}}{ital h}{sup +}{ital h}{sup {minus}}({pi}{sup 0}){nu}{sub {tau}}{bold )}, where {ital h} refers to either a charged {pi} or {ital K}. These branching fractions are measured with samples of lepton-tagged and 3 vs 3 events. We find {ital B}({tau}{sup {minus}}{r_arrow}{ital h}{sup {minus}}{ital h}{sup +}{ital h}{sup {minus}}{nu}{sub {tau}})=0.0951{plus_minus}0.0007 m*0.0020 and {ital B}({tau}{sup {minus}}{r_arrow}{ital h}{sup {minus}}{ital h}{sup +}{ital h}{sup {minus}}{pi}{sup 0}{nu}{sub {tau}})=0.0423{plus_minus} .0006{plus_minus}0.0022. We also measure {ital B}({tau}{sup {minus}}{r_arrow}{omega}{ital h}{sup {minus}}{nu}{sub {tau}})=0.0195{plus_minus}0.0007{plus_minus}0.0011 {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.

First Observation of the Cabibbo Suppressed Decay {ital B}{sup {ital +}}{ital {r_arrow} {bar {ital D}}}{sup {ital 0}}{ital K}{sup +}

Energy Technology Data Exchange (ETDEWEB)

Athanas, M.; Avery, P.; Jones, C.D.; Lohner, M.; Patton, S.; Prescott, C.; Yelton, J.; Zheng, J. [University of Florida, Gainesville, Florida 32611 (United States); Brandenburg, G.; Briere, R.A.; Ershov, A.; Gao, Y.S.; Kim, D.Y.; Wilson, R.; Yamamoto, H. [Harvard University, Cambridge, Massachusetts 02138 (United States); Browder, T.E.; Li, Y.; Rodriguez, J.L. [University of Hawaii at Manoa, Honolulu, Hawaii 96822 (United States); Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Hans, R.M.; Johnson, E.; Karliner, I.; Marsh, M.A.; Palmer, M.; Selen, M.; Thaler, J.J. [University of Illinois, Urbana-Champaign, Illinois 61801 (United States); Edwards, K.W. [Carleton University, Ottawa, Ontario, Canada K1S 5B6 and the Institute of Particle Physics (Canada); Bellerive, A.; Janicek, R.; MacFarlane, D.B.; Patel, P.M. [McGill University, Montreal, Quebec, Canada H3A 2T8 and the Institute of Particle Physics (Canada); Sadoff, A.J. [Ithaca College, Ithaca, New York 14850 (United States); Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Darling, C.; Davis, R.; Kotov, S.; Kravchenko, I.; Kwak, N.; Zhou, L. [University of Kansas, Lawrence, Kansas 66045 (United States); Anderson, S.; Kubota, Y.; Lee, S.J.; ONeill, J.J.; Poling, R.; Riehle, T.; Smith, A. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Duboscq, J.E.; Fujino, D.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wolf, A.; Zoeller, M.M. [The Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Severini, H.; Skubic, P. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; and others

1998-06-01

We have observed the decay B{sup +}{r_arrow}{bar D}{sup 0} K{sup +} , using 3.3{times}10{sup 6} B{bar B} pairs collected with the CLEO II detector at the Cornell Electron Storage Ring. We find the ratio of branching fractions R{equivalent_to}B(B{sup +}{r_arrow}{bar D}{sup 0}K{sup +})/B(B{sup +}{r_arrow}{bar D}{sup 0}{pi}{sup +})=0.055{plus_minus}0.014{plus_minus}0.005 . {copyright} {ital 1998} {ital The American Physical Society}

Arrow physicians: are economics and medicine philosophically incompatible?

Science.gov (United States)

Tsang, Sandro

2015-06-01

Economics is en route to its further expansion in medicine, but many in the medical community remain unconvinced that its impact will be positive. Thus, a philosophical enquiry into the compatibility of economics and medicine is necessary to resolve the disagreements. The fundamental mission of medicine obliges physicians to practise science and compassion to serve the patient's best interests. Conventional (neoclassical) economics assumes that individuals are self-interested and that competitive markets will emerge optimal states. Economics is seemingly incompatible with the emphasis of putting patients' interests first. This idea is refuted by Professor Kenneth Arrow's health economics seminal paper. Arrow emphasizes that medical practice involves agency, knowledge, trust and professionalism, and physician-patient relation critically affects care quality. The term Arrow Physician is used to mean a humanistic carer who has a concern for the patient and acts on the best available evidence with health equity in mind. To make this practice sustainable, implementing appropriate motivations, constitutions and institutions to enable altruistic agency is critical. There is substantial evidence that polycentric governance can encourage building trust and reciprocity, so as to avoid depletion of communal resources. This paper proposes building trusting institutions through granting altruistic physicians adequate autonomy to direct resources based on patients' technical needs. It also summarizes the philosophy bases of medicine and economics. It, therefore, contributes to developing a shared language to facilitate intellectual dialogues, and will encourage trans-disciplinary research into medical practice. This should lead to medicine being reoriented to care for whole persons again. © 2015 John Wiley & Sons, Ltd.

Control of Eospalax baileyi (Plateau Zokor) with arrow traps in western China

NARCIS (Netherlands)

Kong, Yang; Xidong, Li; Gaowei, Xu; Wei, Liu; Meerburg, B.G.

2016-01-01

In order to manage Eospalax (Myospalax) baileyi (Plateau zokors) pests with physical method, the efficacy of four different arrow traps was tested to control the plateau zokor in Sichuan Northwest Prairie, China. Population densities of 39.7-42.1 ha-1 were found in the test plots. Such densities

Form factors of the transitions {gamma}{sup *}{pi}{sup 0} {r_arrow} {gamma} and {gamma}{sup *}{eta}{r_arrow}{gamma}

Energy Technology Data Exchange (ETDEWEB)

Afanasev, A. [Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

1994-04-01

The author discusses possibilities to study {gamma}*{pi}{sup 0} and {gamma}*{eta} {r_arrow} {gamma} transition form factors at CEBAF energies. The author shows that for 4 GeV electron beam, these form factors can be measured at CEBAF for the 4-momentum transfers Q{sup 2} {le} 2.5 (GeV/c){sup 2} using virtual Compton scattering on the proton and nuclear target in the kinematic regime of low momentum transfers to the target. These measurements can be extended to Q{sup 2} {le} 4.0 (GeV/c){sup 2} using the electron beam with the energy 6 GeV.

Language of Mechanisms: Exam Analysis Reveals Students' Strengths, Strategies, and Errors When Using the Electron-Pushing Formalism (Curved Arrows) in New Reactions

Science.gov (United States)

Flynn, Alison B.; Featherstone, Ryan B.

2017-01-01

This study investigated students' successes, strategies, and common errors in their answers to questions that involved the electron-pushing (curved arrow) formalism (EPF), part of organic chemistry's language. We analyzed students' answers to two question types on midterms and final exams: (1) draw the electron-pushing arrows of a reaction step,…

The physics of time and the arrow thereof

Science.gov (United States)

Hecht, Eugene

2018-01-01

Although the physics of time is of fundamental importance, the concept gets little attention in most introductory courses. Still, we now know enough to begin to formulate a coherent account of the physical nature of time. Newton’s absolute time has given way to Leibniz’s relational time. From Relativity Theory we learn that time in addition to being relational is also relative, and local; as we will see, the rates at which events unfold are influenced by both the relative velocity of the observer, and the local gravitational field strength—time is not universal. The intrinsic relationship between light-speed and time will be examined via relativity. Moreover, it will be shown that the Special Theory requires that the quanta of the electromagnetic field (i.e. photons), only exist at speed c; the ramifications of that extraordinary property, coupled with conservation of energy, profoundly influence the progression of time. Time in our everyday lives is the abstract measure of the unfolding of macroscopic occurrences, all of which are irreversible. It is posited that these events are irreversible because they are invariably accompanied by the emission of radiant energy, photons and/or gravitons. By contrast, entropy is a descriptor of processes, it is not a causative agency; although correlated with the so-called arrow-of-time, it cannot be its cause. Using a variety of physical thought experiments, it will be shown that the unidirectional ‘flow’ of time, the arrow-of-time, is a result of the fact that energy quanta only travel toward the future. That is the fundamental asymmetry in our otherwise temporally symmetric physics.

Observation of the isospin-violating decay {ital D}{sub {ital s}}{sup *+}{r_arrow}{ital D}{sup +}{sub {ital s}}{pi}{sup 0}

Energy Technology Data Exchange (ETDEWEB)

Gronberg, J.; Korte, C.M.; Kutschke, R.; Menary, S.; Morrison, R.J.; Nakanishi, S.; Nelson, H.N.; Nelson, T.K.; Qiao, C.; Richman, J.D.; Roberts, D.; Ryd, A.; Tajima, H.; Witherell, M.S.; Balest, R.; Cho, K.; Ford, W.T.; Lohner, M.; Park, H.; Rankin, P.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berger, B.E.; Berkelman, K.; Bloom, K.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Dickson, M.; Drell, P.S.; Dumas, D.J.; Ehrlich, R.; Elia, R.; Gaidarev, P.; Garcia-Sciveres, M.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Lee, T.; Liu, Y.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Avery, P.; Freyberger, A.; Lingel, K.; Prescott, C.; Rodriguez, J.; Yang, S.; Yelton, J.; Brandenburg, G.; Cinabro, D.; Liu, T.; Saulnier, M.; Wilson, R.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Palmer, M.; Selen, M.; Thaler, J.J.; Edwards, K.W.; McLean, K.W.; Ogg, M.; Bellerive, A.; Britton, D.I.; Hyatt, E.R.F.; Janicek, R.; MacFarlane, D.B.; Patel, P.M.; Spaan, B.; Sadoff, A.J.; Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Copty, N.; Davis, R.; Hancock, N.; Kotov, S.; Kravchenko, I.; Kwak, N.; Kubota, Y.; Lattery, M.; Momayezi, M.; Nelson, J.K.; Patton, S.; Poling, R.; Savinov, V.; Schrenk, S.; Wang, R.; Alam, M.S.; Kim, I.J.; Ling, Z.; Mahmood, A.H.; O`Neill, J.J.; Severini, H.; Sun, C.R.; Wappler, F.; Crawford, G.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; White, C.; Wolf, A.; Zoeller, M.M.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; Miao, T.; Miller, D.H.; Modesitt, M.; Shibata, E.I.; Shipsey, I.P.J.; Wang, P.N.; Gibbons, L.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H.; Coan, T.; (CLEO Co...

1995-10-30

Using data collected with the CLEO II detector, we have observed the isospin-violating decay {ital D}{sub {ital s}}{sup *+}{r_arrow}{ital D}{sup +}{sub {ital s}}{pi}{sup 0}. The decay rate for this mode, relative to the dominant radiative decay, is found to be {Gamma}({ital D}{sub {ital s}}{sup *+}{r_arrow}{ital D}{sup +}{sub {ital s}}{pi}{sup 0}) /{Gamma}({ital D}{sub {ital s}}{sup *+}{r_arrow}{ital D}{sup +}{ital s}{gamma}) =0.062{sub {minus}0.018}{sup +0.020}{plus_minus}0.022. {copyright} {ital 1995} {ital The} {ital American} {ital Physical} {ital Society}.

Is the pull-out force of the Meniscus Arrow in bone affected by the inward curling of the barbs during biodegradation? An in vitro study

NARCIS (Netherlands)

Wouters, Diederick B.; Burgerhof, Johannes G. M.; de Hosson, Jeff T. M.; Bos, Rudolf R. M.

Background: Inward curling of the barbs of Meniscus Arrows during degradation was observed in a previous study, in which swelling, distention, and water uptake by Meniscus Arrows was evaluated. This change of configuration could have consequences with respect to anchorage capacity in bone.

Early Twentieth Century Arrow, Javelin, and Dart Games of the Western Native American.

Science.gov (United States)

Pesavento, Wilma J.

The general purpose of this study was to determine whether the traditional native American ball games continued to be positive culture traits of the American Indian in the early twentieth century. The investigation was centered about (1) determining the current arrow, javelin, and dart games of western native Americans, (2) determining the…

Is the pull-out force of the Meniscus Arrow in bone affected by the inward curling of the barbs during biodegradation? An in vitro study.

Science.gov (United States)

Wouters, Diederick B; Burgerhof, Johannes G M; de Hosson, Jeff T M; Bos, Rudolf R M

2009-04-01

Inward curling of the barbs of Meniscus Arrows during degradation was observed in a previous study, in which swelling, distention, and water uptake by Meniscus Arrows was evaluated. This change of configuration could have consequences with respect to anchorage capacity in bone. Eight non-degraded Meniscus Arrows in the original configuration were pulled out of thawed, fresh-frozen human femoral condyle, and pull-out force was measured and compared with that of 6 Meniscus Arrows after 31 days of degradation under controlled conditions. No significant difference was found between the 2 groups with respect to the required pull-out force (t test), the distribution of the data, or the interaction between degradation and location, as evaluated by Mann-Whitney test, and no significant difference was found between the 2 groups with respect to the degradation state or position in the condyles, as evaluated by 2-way analysis of variance. Our results indicate that the decrease in barb-barb diameter during the first month of degradation of the Meniscus Arrows has no significant effect on the tensile pull-out force required for removal from human femur condyle. Further research should be undertaken to examine whether the same is true for other biodegradable devices with barbs.

Polarization of cumulative protons in the reaction. gamma. A r arrow pX

Energy Technology Data Exchange (ETDEWEB)

Avakyan, R.O.; Avetisyan, A.E.; Arestakesyan, G.A.; Bartikyan, M.V.; Garibyan, Y.A.; Grigoryan, A.E.; Eganov, V.S.; Karapetyan, A.P.; Karapetyan, M.P.; Keropyan, I.A.; and others

1989-02-01

The polarization of cumulative protons has been measured in the reaction {gamma}{ital A}{r arrow}{ital pX} in the proton-energy region 170--270 MeV for C and Sn nuclei in bremsstrahlung beams produced by 4.5- and 1.5-GeV electrons. The measured polarization value is close to zero.

El principio KKM en estructuras de convexidad generalizaday aplicaciones a la teoría económica

Directory of Open Access Journals (Sweden)

José Manuel Huertas Fernández

2005-01-01

Full Text Available El Principio KKM (Knaster-Kuratowski-Mazurkiewicz juega un papel fundamental en el desarrollo de la Teoría Económica, con origen en los trabajos de formalización de Debreu-Arrow, y está estrechamente relacionada con problemas de equilibrio, el principio del minimax, teoría de juegos y otros aspectos en la modelización económica. El Principio KKM se convirtió en una herramienta de gran utilidad en los años 60 y los estudios sobre el mismo se han prolongado hasta la actualidad. Por su propia naturaleza, este es un principio íntimamente ligado con la convexidad del espacio donde se trabaja. Sin embargo en los últimos quince años se ha creado toda una teoría del Principio KKM en espacios de convexidad generalizada (espacios donde aún no pudiéndose hablar de una estructura convexa en sentido clásico, sí se pueden encontrar ciertas estructuras que, de algún modo, conservan algunas de la propiedades que garantiza la convexidad clásica. En esta charla mostraremos cómo se definen estas nuevas estructuras y cómo es posible obtener el Principio KKM sobre las mismas. Este campo de la matemática económica ha sido objeto de estudio de muchos investigadores en los últimos años como muestra la larga colección de trabajos publicados sobre el mismo en revistas como J. of Econom. Theory, Ec. Theory o J. Math. Econom.

Geochemistry of the Oruatemanu Formation, Arrow Rocks, Northland, New Zealand

International Nuclear Information System (INIS)

Hori, R.S.; Higuchi, Y.; Fujiki, T.; Maeda, T.; Ikehara, M.

2007-01-01

We investigated the geochemical characteristics of sedimentary rocks from the Upper Permian - Middle Triassic Oruatemanu Formation on Arrow Rocks, Waipapa Terrane, New Zealand. The sedimentary rocks consist of limestone, tuffaceous shale, vari-coloured bedded chert, hemipelagic shale and green siliceous mudstone (= green argillite), in ascending order, a typical oceanic plate sequence. Shale and green argillite have higher Zr/Nb ratios than do chert and tuffaceous shales, and show similar REE patterns to PAAS (Post-Archean average Australian shale). In contrast, chert sequences from the basal part and intercalated tuff layers have high TiO 2 contents and Zr/Nb ratios similar to those of basaltic rocks from Arrow Rocks. These geochemical characteristics suggest that the sedimentary environment of the Oruatemanu Formation changed upward, from an open sea setting to the continental margin of Gondwanaland. Chemical compositions of bedded cherts from Arrow Rocks indicate a mixing of biogenic silica, detritus from continents and basaltic materials. In the interval from Upper Permian to Lower Middle Triassic this mixing shows remarkable secular variations. We detected geochemical signals of two Oceanic Anoxic Events (OAEs), one at the Permian/Triassic (P/T) boundary, and the other at the middle Upper Induan level. We name them the OAEα (P/T OAE) and OAEβ (Upper Induan OAE). These OAE horizons are enriched in S, U and other heavy metals (e.g. Mo and Cr), and also have high V/(V+Ni) ratios. Based on a comparison between enrichment factors of Cr and other redox-sensitive trace elements (e.g. Zn, Pb, Co, Cu), the Upper Induan OAEβ is considered to be more intense than the P/T boundary OAEα. This result is not in agreement with the superanoxia model previously proposed. In addition, OAEβ corresponds well with the radiolarian faunal turnover from Permian to Triassic forms documented from the Oruatemanu Formation in this volume. These results may suggest that peak time and

Non-intentional but not automatic: reduction of word- and arrow-based compatibility effects by sound distractors in the same categorical domain.

Science.gov (United States)

Miles, James D; Proctor, Robert W

2009-10-01

In the current study, we show that the non-intentional processing of visually presented words and symbols can be attenuated by sounds. Importantly, this attenuation is dependent on the similarity in categorical domain between the sounds and words or symbols. Participants performed a task in which left or right responses were made contingent on the color of a centrally presented target that was either a location word (LEFT or RIGHT) or a left or right arrow. Responses were faster when they were on the side congruent with the word or arrow. This bias was reduced for location words by a neutral spoken word and for arrows by a tone series, but not vice versa. We suggest that words and symbols are processed with minimal attentional requirements until they are categorized into specific knowledge domains, but then become sensitive to other information within the same domain regardless of the similarity between modalities.

Javelin, Arrow, Dart and Pin Games of Native American Women of the Plains.

Science.gov (United States)

Pesavento, Wilma J.; Pesavento, Lisa C.

This study was designed to determine (1) the arrow, dart, javelin, and pin games of Native American girls and women of the Great Plains, (2) the geographical spread of the games within the culture area, and (3) the characteristics of the various games. Data for this investigation were researched from "Annual Reports of the Bureau of American…

Arrows as anchors: An analysis of the material features of electric field vector arrows

Science.gov (United States)

Gire, Elizabeth; Price, Edward

2014-12-01

Representations in physics possess both physical and conceptual aspects that are fundamentally intertwined and can interact to support or hinder sense making and computation. We use distributed cognition and the theory of conceptual blending with material anchors to interpret the roles of conceptual and material features of representations in students' use of representations for computation. We focus on the vector-arrows representation of electric fields and describe this representation as a conceptual blend of electric field concepts, physical space, and the material features of the representation (i.e., the physical writing and the surface upon which it is drawn). In this representation, spatial extent (e.g., distance on paper) is used to represent both distances in coordinate space and magnitudes of electric field vectors. In conceptual blending theory, this conflation is described as a clash between the input spaces in the blend. We explore the benefits and drawbacks of this clash, as well as other features of this representation. This analysis is illustrated with examples from clinical problem-solving interviews with upper-division physics majors. We see that while these intermediate physics students make a variety of errors using this representation, they also use the geometric features of the representation to add electric field contributions and to organize the problem situation productively.

Arrows as anchors: An analysis of the material features of electric field vector arrows

Directory of Open Access Journals (Sweden)

Elizabeth Gire

2014-08-01

Full Text Available Representations in physics possess both physical and conceptual aspects that are fundamentally intertwined and can interact to support or hinder sense making and computation. We use distributed cognition and the theory of conceptual blending with material anchors to interpret the roles of conceptual and material features of representations in students’ use of representations for computation. We focus on the vector-arrows representation of electric fields and describe this representation as a conceptual blend of electric field concepts, physical space, and the material features of the representation (i.e., the physical writing and the surface upon which it is drawn. In this representation, spatial extent (e.g., distance on paper is used to represent both distances in coordinate space and magnitudes of electric field vectors. In conceptual blending theory, this conflation is described as a clash between the input spaces in the blend. We explore the benefits and drawbacks of this clash, as well as other features of this representation. This analysis is illustrated with examples from clinical problem-solving interviews with upper-division physics majors. We see that while these intermediate physics students make a variety of errors using this representation, they also use the geometric features of the representation to add electric field contributions and to organize the problem situation productively.

26 CFR 48.4161(b)-1 - Imposition and rates of tax; bows and arrows.

Science.gov (United States)

2010-04-01

... 26 Internal Revenue 16 2010-04-01 2010-04-01 true Imposition and rates of tax; bows and arrows. 48.4161(b)-1 Section 48.4161(b)-1 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) MISCELLANEOUS EXCISE TAXES MANUFACTURERS AND RETAILERS EXCISE TAXES Sporting Goods § 48.4161(b)-1...

Six Impossible Mechanisms before Breakfast: Arrow Pushing as an Instructional Device in Inorganic Chemistry

Science.gov (United States)

Berg, Steffen; Ghosh, Abhik

2013-01-01

In a recent article by the authors, the suggestion was made that arrow pushing, a widely used tool in organic chemistry, could also be profitably employed in the teaching of introductory inorganic chemistry. A number of relatively simple reactions were used to illustrate this thesis, raising the question whether the same approach might rationalize…

The emergence of time's arrows and special science laws from physics

OpenAIRE

Loewer, Barry

2011-01-01

In this paper, I will argue that there is an important connection between two questions concerning how certain features of the macro world emerge from the laws and processes of fundamental microphysics and suggest an approach to answering these questions. The approach involves a kind of emergence but quite different from ‘top-down’ emergence discussed at the conference, for which an earlier version of this paper was written. The two questions are (i) How do ‘the arrows of time’ emerge from mi...

Safety effects of traffic signing for left turn flashing yellow arrow signals.

Science.gov (United States)

Schattler, Kerrie L; Gulla, Cody J; Wallenfang, Travis J; Burdett, Beau A; Lund, Jessica A

2015-02-01

In 2010, the left turn flashing yellow arrow (FYA) signal displays were installed at signalized intersections on state routes in the Peoria, Illinois, area. Supplemental traffic signs with text "Left Turn Yield on Flashing Yellow Arrow" were mounted on the mast arm adjacent to the left turn signal at over half of the FYA installations. The purpose of this paper is to present the results of the effectiveness evaluation of the FYA supplemental sign on safety. Analyses are presented on the effects of the FYA supplemental sign for all drivers and a subset of drivers age 65 and older. A crash-based comparison of 164 FYA approaches including 90 approaches with the sign and 74 approaches without the sign showed greater crash reductions when the supplemental FYA sign was present. The results also showed that crashes involving drivers age 65 and older did not experience the same magnitudes of crash reductions as compared to all drivers. The findings of this research indicate that supplemental FYA signs may help in improving safety for left-turning vehicles during the permissive interval. Thus, it is recommended that supplemental signs be used when initially implementing the FYA, and that effort to educate the driving public on new traffic control be made to further improve safety at signalized intersections. Copyright © 2014. Published by Elsevier Ltd.

Self-Assembling of Tetradecylammonium Chain on Swelling High Charge Micas (Na-Mica-3 and Na-Mica-2): Effect of Alkylammonium Concentration and Mica Layer Charge.

Science.gov (United States)

Pazos, M Carolina; Cota, Agustín; Osuna, Francisco J; Pavón, Esperanza; Alba, María D

2015-04-21

A family of tetradecylammonium micas is synthesized using synthetic swelling micas with high layer charge (Na(n)Si(8-n)Al(n)Mg6F4O20·XH2O, where n = 2 and 3) exchanged with tetradecylammonium cations. The molecular arrangement of the surfactant is elucidated on the basis of XRD patterns and DTA. The ordering conformation of the surfactant molecules into the interlayer space of micas is investigated by IR/FT, (13)C, (27)Al, and (29)Si MAS NMR. The structural arrangement of the tetradecylammonium cation in the interlayer space of high-charge micas is more sensitive to the effect of the mica layer charge at high concentration. The surfactant arrangement is found to follow the bilayer-paraffin model for all values of layer charge and surfactant concentration. However, at initial concentration below the mica CEC, a lateral monolayer is also observed. The amount of ordered conformation all-trans is directly proportional to the layer charge and surfactant concentration.

Social Conflicts in Arrow Of God: Lessons in Flexibility and Good Governance

Directory of Open Access Journals (Sweden)

Anaso George Nworah

2016-01-01

Full Text Available Chinua Achebe’s second novel, Arrow of God, is concerned with the theme of conflict. According to Holman C. Hugh (1960, there are four basic levels of conflict: struggle between the protagonist and the antagonist, the protagonist with the society, struggle in the mind of the protagonist or the protagonist struggling with fate, destiny or force of nature. Conflicts in Arrow of God delineate three of these struggles in a concentration of events leading to the destruction of the social order in the community (Umuaro. However, the conflicts are linked with colonialism which is at the root of the conflict. In this view, the novel is to some extent, a protest against colonialism and the suffering that it brought to the colonised people generally and the Igbo specifically. Arising from the above, this paper draws some implications from the actions of the protagonist to reveal the connection between a leader’s flexibility and good governance as reflected in the life of the old chief priest (Ezeulu. The novel made its debut in 1964, symbolically marking a year since Nigeria’s adoption of Republican Constitution. The connection between Umuaro’s institution of Ulu and its priest as source of law and order with Nigeria’s adoption of the republican constitution is made obvious in this study. Through this, the nexus between literature and reality is thus reinforced. Keywords: Colonialism, Conflict, Myth, Protest, Governance, Republicanism

The Geohistorical Time Arrow: From Steno's Stratigraphic Principles to Boltzmann's Past Hypothesis

Science.gov (United States)

Kravitz, Gadi

2014-01-01

Geologists have always embraced the time arrow in order to reconstruct the past geology of Earth, thus turning geology into a historical science. The covert assumption regarding the direction of time from past to present appears in Nicolas Steno's principles of stratigraphy. The intuitive-metaphysical nature of Steno's assumption was based on a…

The arthroscopic treatment of displaced tibial spine fractures in children and adolescents using Meniscus Arrows(A (R))

NARCIS (Netherlands)

Wouters, Diederick B.; de Graaf, Joost S.; Hemmer, Patrick H.; Burgerhof, Johannes G. M.; Kramer, William L. M.

This article summarises the results of a newly developed technique that utilises Meniscus Arrows(A (R)) for the arthroscopic fixation of displaced tibial spine fractures in children and adolescents. Twelve tibial spine fractures in the knees of eleven children between 6 and 15 years old, with an

TETRAHEURÍSTICA SISTÉMICA (THS PARA EL TSP SYSTEMIC TETRAHEURISTIC FOR THE TSP

Directory of Open Access Journals (Sweden)

Jorge Iván Pérez Rave

2010-08-01

Full Text Available Este artículo presenta un novedoso método, basado en elementos del pensamiento sistémico, para solucionar instancias del problema del vendedor viajero (TSP, el cual es comparado en términos de eficacia y eficiencia con "nearest neighbour", "cheapest insertion", "two-wwy exchange improvement" y "branch and bound". El primer apartado introduce la optimización combinatoria, el segundo ofrece un marco de referencia, el tercero presenta la metodología empleada, el cuarto apartado presenta el desarrollo de la tetraheurística sistémica, seguido del análisis de varianza y de rangos de Duncan para los factores: método y cantidad de ciudades; este apartado finaliza con el análisis del comportamiento de la proporción de "fracasos" del algoritmo propuesto a medida que aumenta la complejidad del TSP. Como resultado se obtiene un método para resolver instancias del TSP, conformado por tres heurísticas misionales: 1."vecino más cercano", 2. "sacrificio cortoplacista" y 3. "traslado LIFO", y una de apoyo llamada "búsqueda derecha 4P4". El diseño de la heurística denominada "sacrificio cortoplacista" es inspirado en el análisis sistémico del "vecino más cercano", al cual se le identifica el arquetipo de "soluciones rápidas que fallan", con aplicación a decisiones cotidianas. La tetraheurística sistémica se destaca, respecto a las demás, en solución arrojada y en tiempo computacional consumido, especialmente cuando incrementa la complejidad del TSP.This paper presents a novel method to solve instances of the TSP. This method is comparable in effectiveness and efficiency with "nearest neighbour", "cheapest insertion", "two-way exchange improvement" and "branch and bound". The first section provides a literature review of the combinatorial optimization, the second provides a reference frame, the third the methodology used and the fourth contains, inter alia, system thinking, AxB factorial design and management tool CAP-DO. The fourth

The emergence of time's arrows and special science laws from physics.

Science.gov (United States)

Loewer, Barry

2012-02-06

In this paper, I will argue that there is an important connection between two questions concerning how certain features of the macro world emerge from the laws and processes of fundamental microphysics and suggest an approach to answering these questions. The approach involves a kind of emergence but quite different from 'top-down' emergence discussed at the conference, for which an earlier version of this paper was written. The two questions are (i) How do 'the arrows of time' emerge from microphysics? (ii) How do macroscopic special science laws and causation emerge from microphysics? Answering these questions is especially urgent for those, who like myself, think that a certain version of physicalism, which I call 'micro-physical completeness' (MC), is true. According to MC, there are fundamental dynamical laws that completely govern (deterministically or probabilistically), the evolution of all micro-physical events and there are no additional ontologically independent dynamical or causal special science laws. In other words, there is no ontologically independent 'top-down' causation. Of course, MC does not imply that physicists now or ever will know or propose the complete laws of physics. Or even if the complete laws were known we would know how special science properties and laws reduce to laws and properties of fundamental physics. Rather, MC is a contingent metaphysical claim about the laws of our world. After a discussion of the two questions, I will argue the key to showing how it is possible for the arrows of time and the special science laws to emerge from microphysics and a certain account of how thermodynamics is related to fundamental dynamical laws.

Is the hypothesis about a low entropy initial state of the Universe necessary for explaining the arrow of time?

Science.gov (United States)

Goldstein, Sheldon; Tumulka, Roderich; Zanghı, Nino

2016-07-01

According to statistical mechanics, microstates of an isolated physical system (say, a gas in a box) at time t0 in a given macrostate of less-than-maximal entropy typically evolve in such a way that the entropy at time t increases with |t -t0| in both time directions. In order to account for the observed entropy increase in only one time direction, the thermodynamic arrow of time, one usually appeals to the hypothesis that the initial state of the Universe was one of very low entropy. In certain recent models of cosmology, however, no hypothesis about the initial state of the Universe is invoked. We discuss how the emergence of a thermodynamic arrow of time in such models can nevertheless be compatible with the above-mentioned consequence of statistical mechanics, appearances to the contrary notwithstanding.

Na(3p left-arrow 3s) excitation by impact of slow multiply charged ions

International Nuclear Information System (INIS)

Horvath, G.; Schweinzer, J.; Winter, H.; Aumayr, F.

1996-01-01

We present a systematic experimental and theoretical study of Na(3p left-arrow 3s) excitation by slow (v NaI with projectile ion charge state q is investigated. Due to the dominance of the competing electron capture channels at low collision energies E, the excitation cross sections deviate significantly from a commonly applied σ/q=f(E/q) cross-section scaling relation. copyright 1996 The American Physical Society

‘An augury of the world’s ruin’ and the making of the tragic hero in Chinua Achebe’s Arrow of God

Directory of Open Access Journals (Sweden)

Ignatius Chukwumah

2016-06-01

Full Text Available Chinua Achebe’s Arrow of God has been adjudged by critics as a tragic work with Ezeulu as its tragic hero. However, none of these studies has paid detailed attention to the framing of Ezeulu in the historical context of his age. How he appears when compared to a classical Greek tragic hero has also been ignored. A major context giving rise to Ezeulu becoming a tragic hero is the period leading to the synthesis of two contrary histories, juxtaposed discourses and the collision of opposites and contraries in the sociocultural and political sphere of the villages of Umuaro and Okperi. This circumstance is captured by the narrator as ‘an augury of the world’s ruin’, by Nwaka as ‘the white man turned us upside down’ and by Ezeulu as ‘the world is spoilt and there is no longer head or tail in anything that is done’. Allen, an earlier District Commissioner in Things Fall Apart, but textually implicated in Arrow of God, terms it ‘great situations’. The above historical context requires more than mastery and acknowledgement by the tragic figure, in the absence of which he, a self-professed knowledgeable person, becomes a victim of what he failed to take into account. Consequently, he is set aside as a specimen for history and other men. This article will use Hegel’s and Aristotle’s theories of history and of tragedy, respectively, to explicate the above. It concludes that the tragic hero of Chinua Achebe’s Arrow of God is substantially the victim of the clash between Umuaro’s history and Hegel’s History. ’n Teken van die wêreld se ondergang en die skepping van die tragiese held in Chinua Achebe se Arrow of God. Chinua Achebe se boek, Arrow of God, word deur kritici beskryf as ’n tragedie met die karakter Ezeulu as held. Niemand het egter noukeurige aandag geskenk aan hoe Ezeulu inpas in die gapings van botsende geskiedenisse soos vergestalt in die mens ten opsigte van hulle optredes, houdings, vrese en begeertes nie

Final evaluation report for Lockheed Idaho Technologies Company, ARROW-PAK packaging, Docket 95-40-7A, Type A container

International Nuclear Information System (INIS)

Kelly, D.L.

1995-11-01

The report documents the U.S. Department of Transportation Specification 7A Type A (DOT-7A) compliance test results of the ARROW-PAK packaging. The ARROW-PAK packaging system consists of Marlex M-8000 Driscopipe (Series 8000 [gas] or Series 8600 [industrial]) resin pipe, manufactured by Phillips-Driscopipe, Inc., and is sealed with two dome-shaped end caps manufactured from the same materials. The patented sealing process involves the use of electrical energy to heat opposing faces of the pipe and end caps, and hydraulic rams to press the heated surfaces together. This fusion process produces a homogeneous bonding of the end cap to the pipe. The packaging may be used with or without the two internal plywood spacers. This packaging was evaluated and tested in October 1995. The packaging configuration described in this report is designed to ship Type A quantities of solid radioactive materials, Form No. 1, Form No. 2, and Form No. 3

Cosmic update dark puzzles : arrow of time : future history

CERN Document Server

Adams, Fred; Mersini-Houghton, Laura; Nekoogar, Farzad

2012-01-01

"...The Multiversal book series is equally unique, providing book-length extensions of the lectures with enough additional depth for those who truly want to explore these fields, while also providing the kind of clarity that is appropriate for interested lay people to grasp the general principles involved." - Lawrence M. Krauss Cosmic Update covers: A novel approach to uncover the dark faces of the Standard Model of cosmology. The possibility that Dark Energy and Dark Matter are manifestations of the inhomogeneous geometry of our Universe. The history of cosmological model building and the general architecture of cosmological models. Illustrations of the Large Scale Structure of the Universe. A new perspective on the classical static Einstein Cosmos. Global properties of World Models including their Topology. The Arrow of Time in a Universe with a Positive Cosmological Constant. The exploration of the consequences of a fundamental Cosmological Constant for our Universe. The exploration of why the current ob...

Field measurements of biogenic volatile organic compounds in the atmosphere using solid-phase microextraction Arrow

Science.gov (United States)

Feijó Barreira, Luís Miguel; Duporté, Geoffroy; Rönkkö, Tuukka; Parshintsev, Jevgeni; Hartonen, Kari; Hyrsky, Lydia; Heikkinen, Enna; Jussila, Matti; Kulmala, Markku; Riekkola, Marja-Liisa

2018-02-01

Biogenic volatile organic compounds (BVOCs) emitted by terrestrial vegetation participate in a diversity of natural processes. These compounds impact both short-range processes, such as on plant protection and communication, and long-range processes, for example by participating in aerosol particle formation and growth. The biodiversity of plant species around the Earth, the vast assortment of emitted BVOCs, and their trace atmospheric concentrations contribute to the substantial remaining uncertainties about the effects of these compounds on atmospheric chemistry and physics, and call for the development of novel collection devices that can offer portability with improved selectivity and capacity. In this study, a novel solid-phase microextraction (SPME) Arrow sampling system was used for the static and dynamic collection of BVOCs from a boreal forest, and samples were subsequently analyzed on site by gas chromatography-mass spectrometry (GC-MS). This system offers higher sampling capacity and improved robustness when compared to traditional equilibrium-based SPME techniques, such as SPME fibers. Field measurements were performed in summer 2017 at the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR II) in Hyytiälä, Finland. Complementary laboratory tests were also performed to compare the SPME-based techniques under controlled experimental conditions and to evaluate the effect of temperature and relative humidity on their extraction performance. The most abundant monoterpenes and aldehydes were successfully collected. A significant improvement on sampling capacity was observed with the new SPME Arrow system over SPME fibers, with collected amounts being approximately 2 × higher for monoterpenes and 7-8 × higher for aldehydes. BVOC species exhibited different affinities for the type of sorbent materials used (polydimethylsiloxane (PDMS)-carbon wide range (WR) vs. PDMS-divinylbenzene (DVB)). Higher extraction efficiencies were obtained with dynamic

Mica fission detectors

International Nuclear Information System (INIS)

Wong, C.; Anderson, J.D.; Hansen, L.; Lehn, A.V.; Williamson, M.A.

1977-01-01

The present development status of the mica fission detectors is summarized. It is concluded that the techniques have been refined and developed to a state such that the mica fission counters are a reliable and reproducible detector for fission events

Test and evaluation report for Lockheed Idaho Technologies Company, arrow-pak packaging, docket 95-40-7A, type A container

International Nuclear Information System (INIS)

Kelly, D.L.

1996-01-01

This report incorporates the U.S. Department of Energy, Office of Facility Safety Analysis (DOE/EH-32) approval letter for packaging use. This report documents the U.S. Department of Transportation Specification 7A Type A (DOT-7A) compliance test results of the Arrow-Pak packaging. The Arrow-Pak packaging system consists of Marlex M-8000 Driscopipe, manufactured by Phillips-Driscopipe, Inc., and is sealed with two dome-shaped end caps manufactured from the same materials. The patented sealing process involves the use of electrical energy to heat opposing faces of the pipe and end caps, and hydraulic rams to press the heated surfaces together. This fusion process produces a homogeneous bonding of the end cap to the pipe. The packaging may be used with or without the two internal plywood spacers. This packaging configuration described in this report is designed to ship Type A quantities of solid radioactive materials

Biotermodin?mica en animales

OpenAIRE

Granados Moreno, Jairo Enrique

2014-01-01

El documento presenta como la termodin?mica es la ciencia que estudia las relaciones entre calor y las dem?s formas de transferencias de energ?a. Se explica que toda transformaci?n biofisicoqu?mica implica, generalmente, un cambio energ?tico. Se tratan los conceptos de temperatura, escalas de temperatura, calor, calor de combusti?n, postulados de la termodin?mica, entrop?a y energ?a libre metab?lica

Registro de Cyclocephala flavipennis Arrow, 1914 (Coleoptera: Melolonthidae danificando plantas de mirtileiro no Brasil

Directory of Open Access Journals (Sweden)

Gabriela Inés Diez-Rodríguez

2015-02-01

Full Text Available Larvas de Cyclocephala flavipennis Arrow, 1914, são comumente encontradas em cereais de inverno (trigo, cevada, aveia e triticale, milho e soja, no Rio Grande do Sul. Em março de 2012, larvas desta espécie foram detectadas em plantas de mirtileiro (Vaccinium ashei Reade, cultivar 'O´Neal', no município de Pelotas, RS. Os insetos alimentaram-se de raízes em áreas restritas do pomar. Este é o primeiro relato da ocorrência do coró-pequeno, C. flavipennis, em plantas de mirtileiro

Controlling Attention to Gaze and Arrows in Childhood: An fMRI Study of Typical Development and Autism Spectrum Disorders

Science.gov (United States)

Vaidya, Chandan J.; Foss-Feig, Jennifer; Shook, Devon; Kaplan, Lauren; Kenworthy, Lauren; Gaillard, William D.

2011-01-01

Functional magnetic resonance imaging was used to examine functional anatomy of attention to social (eye gaze) and nonsocial (arrow) communicative stimuli in late childhood and in a disorder defined by atypical processing of social stimuli, Autism Spectrum Disorders (ASD). Children responded to a target word ("LEFT"/"RIGHT") in the context of a…

El estatuto teórico de la niñez y de la juventud en la reflexión económica

Directory of Open Access Journals (Sweden)

Jorge Iván González

2005-01-01

Full Text Available El artículo hace un recuento de la forma como la teoría económica ha incorporado las dimensiones de niñez y juventud. Se diferencian tres espacios temáticos: el primero corresponde al método de la economía; el segundo se refiere a la ruptura que hace Samuelson con el utilitarismo clásico y el tercero muestra alternativas posibles al marco de análisis de Samuelson. Entre los caminos factibles se destacan tres: el primero, formulado por Arrow, abre el espacio samuelsoniano porque propone los estados del mundo como argumentos de la función de utilidad. El segundo camino, relacionado con el nombre de Simon, conjuga biología y economía. Y la tercera vía, estimulada por Sen, está centrada en las capacidades. A medida que la reflexión se distancia de Samuelson, se amplían las posibilidades de incorporar las dimensiones de la niñez y de la juventud en la reflexión económica, pero esta opción obliga a tener una visión interdisciplinar que está ausente en la discusión convencional. El artículo termina con un breve comentario sobre las políticas públicas, e invita al diálogo entre saberes, que es especialmente necesario en el campo de la niñez y la juventud

Observation of the weak time’s arrow in B mesons

CERN Multimedia

CERN. Geneva

2012-01-01

The mechanism of CP violation in weak interactions, as arising from the single physical phase in the CKM matrix, has been validated by more than a decade of intense experimental work probing CP violation, particularly with studies with B mesons. Since the Standard Model theory is CPT invariant, it predicts a “weak arrow of time” matching the large observed matter-antimatter asymmetry in B mesons. However, until recently there has been no direct observation of the expected, large time reversal (T) asymmetry. In this seminar we shall discuss how the BABAR experiment at SLAC has conducted a new data analysis where the decays of entangled neutral B mesons allow comparisons between the rates of four different transitions and their inverse, as a function of the time evolution of the B meson. The results lead to the first high significance, direct observation of T non-invariance through the exchange of initial and final states in transitions that can only be connected by a T symmetry transformation.

Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 3: Sections 12 through 14

Science.gov (United States)

Sakata, I. F.; Davis, G. W.

1975-01-01

The design of an economically viable supersonic cruise aircraft requires the lowest attainable structural-mass fraction commensurate with the selected near-term structural material technology. To achieve this goal of minimum structural-mass fraction, various combinations of promising wing and fuselage primary structure were analyzed for the load-temperature environment applicable to the arrow wing configuration. This analysis was conducted in accordance with the design criteria specified and included extensive use of computer-aided analytical methods to screen the candidate concepts and select the most promising concepts for the in-depth structural analysis.

Duncan F. Gregory, William Walton and the development of British algebra: 'algebraical geometry', 'geometrical algebra', abstraction.

Science.gov (United States)

Verburgt, Lukas M

2016-01-01

This paper provides a detailed account of the period of the complex history of British algebra and geometry between the publication of George Peacock's Treatise on Algebra in 1830 and William Rowan Hamilton's paper on quaternions of 1843. During these years, Duncan Farquharson Gregory and William Walton published several contributions on 'algebraical geometry' and 'geometrical algebra' in the Cambridge Mathematical Journal. These contributions enabled them not only to generalize Peacock's symbolical algebra on the basis of geometrical considerations, but also to initiate the attempts to question the status of Euclidean space as the arbiter of valid geometrical interpretations. At the same time, Gregory and Walton were bound by the limits of symbolical algebra that they themselves made explicit; their work was not and could not be the 'abstract algebra' and 'abstract geometry' of figures such as Hamilton and Cayley. The central argument of the paper is that an understanding of the contributions to 'algebraical geometry' and 'geometrical algebra' of the second generation of 'scientific' symbolical algebraists is essential for a satisfactory explanation of the radical transition from symbolical to abstract algebra that took place in British mathematics in the 1830s-1840s.

Test Plan for Lockheed Idaho Technologies Company (LITCO), ARROW-PAK Packaging, Docket 95-40-7A, Type A Container

International Nuclear Information System (INIS)

Kelly, D.L.

1995-01-01

This report documents the U.S. Department of Transportation Specification 7A Type A (DOT-7A) compliance testing to be followed for qualification of the Lockheed Idaho Technologies Company, ARROW-PAK, for use as a Type A Packaging. The packaging configuration being tested is intended for transportation of radioactive solids, Form No. 1, Form No. 2, and Form No. 3

EL TEOREMA DE LA IMPOSIBILIDAD DE ARROW Y LA ELECCIÓN INTERDEPENDIENTE

Directory of Open Access Journals (Sweden)

Freddy Cante

2000-12-01

Full Text Available Si el problema de la elección social es planteado como un proceso de decisión interdependiente, admitiendo además la comparación interpersonal de las expectativas y estados del mundo de los ciudadanos, y asumiendo que la interacción social implica conflictos negociables y no negociables, es posible prever situaciones de consenso y convivencia social que serian inadmisibles en la rigidez axiomática y lógica del teorema de la imposibilidad de Arrow.I the problem of the social choice is characterized as a process of interdependent decision, also admitting the interpersonal comparison of the expectations and states of the world of citizens and assuming that the social interaction implies negotiable and not negotiable conflicts, it is possible to foresee consent situations and social

Arrow-wing supersonic cruise aircraft structural design concepts evaluation. Volume 4: Sections 15 through 21

Science.gov (United States)

Sakata, I. F.; Davis, G. W.

1975-01-01

The analyses performed to provide structural mass estimates for the arrow wing supersonic cruise aircraft are presented. To realize the full potential for structural mass reduction, a spectrum of approaches for the wing and fuselage primary structure design were investigated. The objective was: (1) to assess the relative merits of various structural arrangements, concepts, and materials; (2) to select the structural approach best suited for the Mach 2.7 environment; and (3) to provide construction details and structural mass estimates based on in-depth structural design studies. Production costs, propulsion-airframe integration, and advanced technology assessment are included.

A microwave inverse Cerenkov Accelerator (MICA)

International Nuclear Information System (INIS)

Hirshfield, Jay L.

1999-01-01

The objective of this Phase II SBIR research program was to complete the final design originated during Phase I for a prototype Microwave Inverse Cerenkov Accelerator (MICA), to fabricate the-prototype MICA, and to test its performance as an electron accelerator. This report contains details of the design, predictions of accelerator performance, results of cold tests on the MICA structure, and details of the installation of MICA on the Yale Beam Physics Laboratory 6-MeV beamline. Discussion of future work is also included

DNA → RNA: What Do Students Think the Arrow Means?

Science.gov (United States)

Fisk, J. Nick; Newman, Dina L.

2014-01-01

The central dogma of molecular biology, a model that has remained intact for decades, describes the transfer of genetic information from DNA to protein though an RNA intermediate. While recent work has illustrated many exceptions to the central dogma, it is still a common model used to describe and study the relationship between genes and protein products. We investigated understanding of central dogma concepts and found that students are not primed to think about information when presented with the canonical figure of the central dogma. We also uncovered conceptual errors in student interpretation of the meaning of the transcription arrow in the central dogma representation; 36% of students (n = 128; all undergraduate levels) described transcription as a chemical conversion of DNA into RNA or suggested that RNA existed before the process of transcription began. Interviews confirm that students with weak conceptual understanding of information flow find inappropriate meaning in the canonical representation of central dogma. Therefore, we suggest that use of this representation during instruction can be counterproductive unless educators are explicit about the underlying meaning. PMID:26086664

Preparation and characterisation of irradiated crab chitosan and New Zealand Arrow squid pen chitosan

International Nuclear Information System (INIS)

Shavandi, Amin; Bekhit, Adnan A.; Bekhit, Alaa El-Din A.; Sun, Zhifa; Ali, M. Azam

2015-01-01

The properties of chitosan from Arrow squid (Nototodarus sloanii) pen (CHS) and commercial crab shell (CHC) were investigated using FTIR, DSC, SEM and XRD before and after irradiation at the dose of 28 kGy in the presence or absence of 5% water. Also, the viscosity, deacetylation degree, water and oil holding capacities, colour and antimicrobial activities of the chitosan samples were determined. Irradiation decreased (P < 0.05) the viscosity of CHC from 0.21 to 0.03 Pa s and of CHS from 1.71 to 0.23 Pa s. The inclusion of water had no effect on the viscosity of irradiated chitosan. Irradiation did not affect the degree of deacetylation of CHC, but increased the deacetylation degree of CHS from 72.78 to 82.29% in samples with 5% water. Water and oil holding capacities of CHS (1197.30% and 873.3%, respectively) were higher (P < 0.05) than those found in CHC (340.70% and 264.40%, respectively). The water and oil holding capacities were decreased for both types of chitosan irradiation, but were not affected by the addition of water. Squid pen chitosan was whiter in colour (White Index = 90.06%) compared to CHC (White Index = 83.70%). Generally, the CHC samples (control and irradiated) exhibited better antibacterial activity compared to CHS, but the opposite was observed with antifungal activity. - Highlights: • Chitosan prepared from Arrow squid pens (Nototodarus sloanii). • Chitosan samples were gamma irradiated at 28 kGy. • Squid pen chitosan showed high fat and water uptake capacities compared to crab shell chitosan. • Gamma irradiation enhanced the DDA of squid pen chitosan but not crab shell chitosan.

Scan path entropy and Arrow plots: Capturing scanning behavior of multiple observers

Directory of Open Access Journals (Sweden)

Ignace T C Hooge

2013-12-01

Full Text Available Designers of visual communication material want their material to attract and retain attention. In marketing research, heat maps, dwell time, and time to AOI first hit are often used as evaluation parameters. Here we present two additional measures 1 scan path entropy to quantify gaze guidance and 2 the arrow plot to visualize the average scan path. Both are based on string representations of scan paths. The latter also incorporates transition matrices and time required for 50% of the observers to first hit AOIs (T50. The new measures were tested in an eye tracking study (48 observers, 39 advertisements. Scan path entropy is a sensible measure for gaze guidance and the new visualization method reveals aspects of the average scan path and gives a better indication in what order global scanning takes place.

21 CFR 73.1350 - Mica-based pearlescent pigments.

Science.gov (United States)

2010-04-01

... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1350 Mica-based pearlescent pigments. (a) Identity. (1) The color additive is formed by depositing titanium and/or iron salts onto mica, followed by...; titanium dioxide and iron oxide on mica. Mica used to manufacture the color additive shall conform in...

21 CFR 73.350 - Mica-based pearlescent pigments.

Science.gov (United States)

2010-04-01

... LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Foods § 73.350 Mica-based pearlescent pigments. (a) Identity. (1) The color additive is formed by depositing titanium salts onto mica, followed by heating to produce titanium dioxide on mica. Mica used to manufacture the color additive shall conform in identity to...

MICA: The Meta-Institute for Computational Astrophysics

Science.gov (United States)

McMillan, Stephen L. W.; Djorgovski, S. G.; Hut, P.; Vesperini, E.; Knop, R.; Portegies Zwart, S.

2009-05-01

We describe MICA, the Meta Institute for Computational Astrophysics, the first professional scientific and educational, non-profit organization based in virtual worlds [VWs]. Most MICA activities are currently conducted in Second Life, arguably the most popular and best developed VW; we plan to expand our presence into other VWs as those venues evolve. The goals of MICA include (1) exploration, development and promotion of VWs and virtual reality [VR] technologies for professional research in astronomy and related fields; (2) development of novel networking venues and mechanisms for virtual scientific communication and interaction, including professional meetings, visualization, and telecollaboration; (3) use of VWs and VR technologies for education and public outreach; and (4) exchange of ideas and joint efforts with other scientific disciplines in promoting these goals for science and scholarship in general. We present representative example of MICA activities and achievements, and outline plans for expansion of the organization. For more information on MICA, please visit http://mica-vw.org .

Acute Antibody-Mediated Rejection in Presence of MICA-DSA and Successful Renal Re-Transplant with Negative-MICA Virtual Crossmatch.

Directory of Open Access Journals (Sweden)

Yingzi Ming

Full Text Available The presence of donor-specific alloantibodies (DSAs against the MICA antigen results in high risk for antibody-mediated rejection (AMR of a transplanted kidney, especially in patients receiving a re-transplant. We describe the incidence of acute C4d+ AMR in a patient who had received a first kidney transplant with a zero HLA antigen mismatch. Retrospective analysis of post-transplant T and B cell crossmatches were negative, but a high level of MICA alloantibody was detected in sera collected both before and after transplant. The DSA against the first allograft mismatched MICA*018 was in the recipient. Flow cytometry and cytotoxicity tests with five samples of freshly isolated human umbilical vein endothelial cells demonstrated the alloantibody nature of patient's MICA-DSA. Prior to the second transplant, a MICA virtual crossmatch and T and B cell crossmatches were used to identify a suitable donor. The patient received a second kidney transplant, and allograft was functioning well at one-year follow-up. Our study indicates that MICA virtual crossmatch is important in selection of a kidney donor if the recipient has been sensitized with MICA antigens.

VECTOR AND TENSOR ANALYZING POWERS IN THE PB-208(D)OVER-RIGHT-ARROW,T)PB-207 REACTION AT 200 AND 360 MEV

NARCIS (Netherlands)

VANDEWIELE, J; LANGEVINJOLIOT, H; GUILLOT, J; ROSIER, LH; WILLIS, A; MORLET, M; DUHAMELCHRETIEN, G; GERLIC, E; TOMASIGUSTAFSSON, E; BLASI, N; MICHELETTI, S; VANDERWERF, SY

Cross sections and vector and tensor analyzing powers for the main levels in Pb-207 have been measured via the Pb-208(d over arrow pointing right, t)Pb-207 reaction at 200 and 360 MeV incident energies. A(y) and A(yy) spin observables allow a clear identification of the valence levels, especially at

Two-mica granites of northeastern Nevada.

Science.gov (United States)

Lee, D.E.; Kistler, R.W.; Friedman, I.; Van Loenen, R. E.

1981-01-01

The field settings are described and analytical data are presented for six two-mica granites from NE Nevada. High delta 18O and 87Sr/86Sr values indicate that all are S-type granite, derived from continental crust. The major element chemistry and accessory mineral contents of these rocks also are characteristic of S-type granites. Chemical, X ray, and other data are presented for the micas recovered from these granites. The muscovites are notably high in Fe2O3, FeO, and MgO. Except for one hydrobiotite, each of the biotites has an MgO content near 6.0 wt%. Two different types of two-mica granites are recognized in the area of this study. One type is distinguished by the presence of many biotite euhedra within muscovite phenocrysts and by an unusual suite of accessory minerals completely devoid of opaque oxides. This type probably resulted from anatexis of late Precambrian argillites under conditions of relatively low oxygen fugacity, along a line that roughly coincides with the westward disappearance of continental basement. In the other textural type of two-mica granite the micas are equigranular and there is a greater variety of accessory minerals. The magmatic evolution of this type also appears to reflect the influence of late Precambrian argillites; there may be age differences between the two types of two-mica granites.-Author

Anomalous directional behaviour of the real parts of the induction arrows in the Eastern Alps. Tectonic and palaeographical implications

Energy Technology Data Exchange (ETDEWEB)

Gurk, M.; Schnegg, P.-A. [Universite' de Neuchatel, Groupe de Geomagnetisme, Institut de Geologie, Neuchatel (Switzerland)

2001-08-01

The electromagnetic induction pattern in the Eastern Alps is characterised by a (continuous) large-scale zone on which the real parts of the induction arrows show anomalous directional behaviour. This zone extends from the Penninic Domain of Eastern Switzerland (Graubuenden) probably into the Carpathian ranges. A coarse mesh of a Magnetotelluric (MT) and Geomagnetic Deep Sounding (GDS) station in the Alps of Graubuenden and Valais (Western Switzerland) indicates that this electromagnetic anomaly is restricted to the Mesozoic sediments of the North Penninic Buendnerschiefer-facies that begins in Eastern Switzerland and extends towards the east beneath Austroalpine, South Penninic and Southalpine units. Striking similarities in position and arrangement between this zone and the magnetic signature in Eastern Alps are found. The analysis of the GDS data with the method of the Hypothetical Event Analysis (HEA) shows that current channelling affects the electromagnetic fields in this zone and causes the anomalous direction of induction arrows. Based on the combined interpretation of GDS data from the Eastern Alps and West Hungary together with the recent data from Switzerland, the following geological implications are discussed: i) a spatial decoupling of induction processes from the upper to the lower crust; ii) a lower crustal conductive structure caused by the identification of the Northern Adriatic promontory or terrane; iii) the eastward continuation of the Buendnerschiefer-facies at least to the tectonic window of Rechnitz.

Anomalous directional behaviour of the real parts of the induction arrows in the Eastern Alps. Tectonic and palaeographical implications

International Nuclear Information System (INIS)

Gurk, M.; Schnegg, P.-A.

2001-01-01

The electromagnetic induction pattern in the Eastern Alps is characterised by a (continuous) large-scale zone on which the real parts of the induction arrows show anomalous directional behaviour. This zone extends from the Penninic Domain of Eastern Switzerland (Graubuenden) probably into the Carpathian ranges. A coarse mesh of a Magnetotelluric (MT) and Geomagnetic Deep Sounding (GDS) station in the Alps of Graubuenden and Valais (Western Switzerland) indicates that this electromagnetic anomaly is restricted to the Mesozoic sediments of the North Penninic Buendnerschiefer-facies that begins in Eastern Switzerland and extends towards the east beneath Austroalpine, South Penninic and Southalpine units. Striking similarities in position and arrangement between this zone and the magnetic signature in Eastern Alps are found. The analysis of the GDS data with the method of the Hypothetical Event Analysis (HEA) shows that current channelling affects the electromagnetic fields in this zone and causes the anomalous direction of induction arrows. Based on the combined interpretation of GDS data from the Eastern Alps and West Hungary together with the recent data from Switzerland, the following geological implications are discussed: i) a spatial decoupling of induction processes from the upper to the lower crust; ii) a lower crustal conductive structure caused by the identification of the Northern Adriatic promontory or terrane; iii) the eastward continuation of the Buendnerschiefer-facies at least to the tectonic window of Rechnitz

SPIN DETERMINATION OF VALENCE AND INNER HOLE STATES VIA THE PB-208((D)OVER-RIGHT-ARROW,T)PB-207 REACTION AT ED=200 MEV

NARCIS (Netherlands)

LANGEVINJOLIOT, H; VANDEWIELE, J; GUILLOT, J; GERLIC, E; ROSIER, LH; WILLIS, A; MORLET, M; DUHAMELCHRETIEN, G; TOMASIGUSTAFSSON, E; BLASI, N; MICHELETTI, S; VANDERWERF, SY

Highly excited neutron hole states in Pb-207 have been studied via the (d, over arrow pointing right, t) reaction at E(d) = 200 MeV using for the first time a polarized beam, with both vector and tensor components. The determination of overlapping neutron hole response functions takes advantage of

La coyuntura económica nacional

Directory of Open Access Journals (Sweden)

Arturo Huerta González

2003-01-01

Full Text Available El objetivo de este artículo es analizar los problemas de contracción económica que enfrenta nuestro país como resultado de la política económica predominante, que lo ha llevado a depender de la economía estadounidense. Cuando ésta enfrentó problemas de crecimiento también frenó el crecimiento de la economía nacional. El gobierno mexicano no instrumenta política fiscal anticíclica (expansión del gasto para contrarrestar la caída de exportaciones y recuperar la dinámica económica por considerar que ello originaría presiones sobre precios y el sector externo y pudiera llevar a un contexto de especulación y crisis. Es por esto que se opta por seguir priorizando políticas contraccionistas para evitar la inflación, como si éste fuese el principal problema del país. Asimismo, el gobierno insiste en las reformas estructurales (apertura eléctrica, petrolera, reforma fiscal y laboral para ampliar la esfera de influencia del sector privado nacional y extranjero y para consolidar el saneamiento fiscal y abaratar el costo de la fuerza de trabajo, impulsando así la dinámica económica. Sin embargo, tales reformas ya las hemos vivido —desde el gobierno de Salinas de Gortari a la fecha— y sus resultados han sido crecimientos espurios que han desembocado en crisis y en el actual estancamiento. Mientras prosiga la actual política económica seguirá deteriorándose la esfera productiva y aumentando el desempleo, sin que se logre un crecimiento sostenido y menos vulnerable de la economía

QUÍMICA VERDE: UN NUEVO RETO

Directory of Open Access Journals (Sweden)

Nerlis Paola Pájaro Castro

2011-01-01

Full Text Available En la actualidad, existe un enorme deterioro del medio ambiente que ha generado la necesidad de buscar alternativas que conduzcan a la sostenibilidad ambiental. Una de estas herramientas es la ¿química verde¿, concepto que contempla el diseño de productos y procesos que reduzcan la generación de sustancias peligrosas y maximicen la eficiencia en la utilización de recursos materiales y energéticos. El empleo de tecnologías menos contaminantes, permitirá a las empresas químicas mitigar los efectos ambientales asociados a su actividad, reduciendo el consumo de materiales e incrementando la participación de recursos renovables. Para alcanzar estas metas, se han propuesto 12 principios básicos de química verde, aplicables en diferentes campos, tales como la medicina, la agricultura, la industria química y farmacéutica. Esta revisión detalla los principios y usos principales de la química verde, y su aplicación como una filosofía de trabajo para avanzar hacia un verdadero desarrollo sostenible.

MICA: Multiple interval-based curve alignment

Science.gov (United States)

Mann, Martin; Kahle, Hans-Peter; Beck, Matthias; Bender, Bela Johannes; Spiecker, Heinrich; Backofen, Rolf

2018-01-01

MICA enables the automatic synchronization of discrete data curves. To this end, characteristic points of the curves' shapes are identified. These landmarks are used within a heuristic curve registration approach to align profile pairs by mapping similar characteristics onto each other. In combination with a progressive alignment scheme, this enables the computation of multiple curve alignments. Multiple curve alignments are needed to derive meaningful representative consensus data of measured time or data series. MICA was already successfully applied to generate representative profiles of tree growth data based on intra-annual wood density profiles or cell formation data. The MICA package provides a command-line and graphical user interface. The R interface enables the direct embedding of multiple curve alignment computation into larger analyses pipelines. Source code, binaries and documentation are freely available at https://github.com/BackofenLab/MICA

Paragenesis of Cr-rich muscovite and chlorite in green-mica ...

Indian Academy of Sciences (India)

peculiar green colour is attributed to the concen- tration of .... mica quartzite, 1g: white mica (paucity of green mica) with ..... lacking in the white micas. 6.2 Chlorites. Chlorites are associated with green micas in the. Palasgaon–Saigaon area. EPMA analysis of the representative chlorites has been obtained. Cations.

Algoritmos para genómica comparativa

OpenAIRE

Figueiras, Vasco da Rocha

2010-01-01

Com o surgimento da Genómica e da Proteómica, a Bioinformática conduziu a alguns dos avanços científicos mais relevantes do século XX. A Unidade de Investigação e Desenvolvimento do Biocant, parque biotecnológico de Cantanhede, assume actualmente o papel de motor no desenvolvimento da Genómica. O Biocant possui um importante sequenciador de larga escala que permite armazenar um elevado número de genomas, nomeadamente, genomas de bactérias. O estudo proposto reflecte a necessidade do Bio...

Differences between tethered polyelectrolyte chains adsorbed onto bare mica and hydrophobically modified mica, comparison with theory.

Science.gov (United States)

Balastre, Marc; Tamashiro, Mario N.; Hernandez, Ernesto; Pincus, Philip; Tirrell, Matthew

2001-03-01

End-grafted polymers generated from the adsorption of asymmetric diblock copolymers on solid surface play an important role in many areas of science and technology. While the small insoluble block acts as an anchor, the charged soluble block confers useful properties to the surface. This study looks at tethered layers of poly(styrene sulfonate)/poly(t-butyl styrene) (PtBS-PSS) adsorbed on both mica (hydrophilic) and octadecyltriethoxysilane (OTE) modified mica (hydrophobic). Normal compressing forces at two different constant grafting densities (bare and modified mica) were measured with the surface force apparatus and compared with theoretical prediction. The effect of salt concentration (Cs) upon the thickness of the self-assembled layers (Lo) was measured in each case. For adsorption of diblock copolymers onto OTE the resulting scaling relationship is much closer to the brush theory, Lo Cs-1/3. This result suggests that the adsorbed amount on mica is not high enough to form a brush.

Questioning the quark model. Strong interaction, gravitation and time arrows. An approach to asymptotic freedom

International Nuclear Information System (INIS)

Basini, G.

2003-01-01

Asymptotic freedom, as a natural result of a theory based on a general approach, derived by a new interpretation of phenomena like the EPR paradox, the black-hole formation and the absence of primary cosmic antimatter is presented. In this approach, conservation laws are considered always and absolutely valid, leading to the possibility of topology changes, and recovering the mutual influence between fundamental forces. Moreover, a new consideration of time arrows leads to asymptotic freedom as a necessary consequence. In fact, asymptotic freedom of strong interactions seems to be a feature common also to gravitational interaction, if induced-gravity theories (t → ∞) are taken into account and a symmetric-time dynamics is recovered in the light of a general conservation principle. (authors)

Questioning the quark model. Strong interaction, gravitation and time arrows. An approach to asymptotic freedom

Energy Technology Data Exchange (ETDEWEB)

Basini, G. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati; Capozziello, S. [E.R. Caianiello, Dipt. di Fisica, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Universita di Salerno, Boronissi, SA (Italy)

2003-09-01

Asymptotic freedom, as a natural result of a theory based on a general approach, derived by a new interpretation of phenomena like the EPR paradox, the black-hole formation and the absence of primary cosmic antimatter is presented. In this approach, conservation laws are considered always and absolutely valid, leading to the possibility of topology changes, and recovering the mutual influence between fundamental forces. Moreover, a new consideration of time arrows leads to asymptotic freedom as a necessary consequence. In fact, asymptotic freedom of strong interactions seems to be a feature common also to gravitational interaction, if induced-gravity theories (t {yields} {infinity}) are taken into account and a symmetric-time dynamics is recovered in the light of a general conservation principle. (authors)

Implementing Quality Criteria in Designing and Conducting a Sequential Quan [right arrow] Qual Mixed Methods Study of Student Engagement with Learning Applied Research Methods Online

Science.gov (United States)

Ivankova, Nataliya V.

2014-01-01

In spite of recent methodological developments related to quality assurance in mixed methods research, practical examples of how to implement quality criteria in designing and conducting sequential QUAN [right arrow] QUAL mixed methods studies to ensure the process is systematic and rigorous remain scarce. This article discusses a three-step…

Química general II

OpenAIRE

Olba Torrent, Amparo

2018-01-01

El document forma part dels materials docents programats mitjançant l'ajut del Servei de Política Lingüística de la Universitat de València Temes de l'assignatura: Química general II del primer curs del Grau de Química Topics of the course: General Chemistry II in the first year of the Degree in Chemistry

La enseñanza de la química desde la perspectiva de la Química Verde

Directory of Open Access Journals (Sweden)

Pía José González García

2016-06-01

Full Text Available La Química Verde, como área de investigación, se comprende como el desarrollo de metodologías para modificar los productos o procesos con la finalidad de reducir o eliminar los riesgos que existen para el medio ambiente y la salud. De este modo, permite proyectar líneas de investigación en la construcción de un conocimiento y enfoques didácticos de las ciencias, y  para ser considerada como parte de los programas Ministeriales. El objetivo del estudio fue conocer y comprender el significado que le otorgan los(as docentes del área a la Química Verde como perspectiva para su enseñanza. A partir de los discursos emanados por los docentes participantes del estudio, se construyeron 4 categorías, las cuales son: la Química Verde como: contexto para la enseñanza de la química, medio de apropiación significativo del aprendizaje de la química, motivadora de la conciencia ambiental y reflejo de la Institución y su relación con los docentes. The teaching of chemistry from the Green Chemistry perspective Green Chemistry (GC, as a research area, understood as the development of methodologies to modify products or processes in order to reduce or eliminate the risks posed to the environment and human health. Thus it is allowing research project lines in building knowledge and didactic approaches of the sciences, and to be considered as part of the ministerial programs. The objective of this study was to know and understand the significance given by teachers in the area to GC as a perspective for education. From the speeches issued by teachers participating in the study, four categories, was built. GC as: context for teaching chemistry, through significant learning chemistry appropriation, motivating environmental awareness and reflection of the institution and its relationship with teachers.  O ensino de química, na perspectiva da Química verde A Química verde, como área de investigação, é compreendida como o desenvolvimento de

Anomalous directional behaviour of the real parts of the induction arrows in the Eastern Alps: tectonic and palaeogeographic implications

Directory of Open Access Journals (Sweden)

P. A. Schnegg

2001-06-01

Full Text Available The electromagnetic induction pattern in the Eastern Alps is characterised by a (continuous large-scale zone on which the real parts of the induction arrows show anomalous directional behaviour. This zone extends from the Penninic Domain of Eastern Switzerland (Graubünden probably into the Carpathian ranges. A coarse mesh of a Magnetotelluric (MT and Geomagnetic Deep Sounding (GDS station in the Alps of Graubünden and Valais (Western Switzerland indicates that this electromagnetic anomaly is restricted to the Mesozoic sediments of the North Penninic Bündnerschiefer-facies that begins in Eastern Switzerland and extends towards the east beneath Austroalpine, South Penninic and Southalpine units. Striking similarities in position and arrangement between this zone and the magnetic signature in the Eastern Alps are found. The analysis of the GDS data with the method of the Hypothetical Event Analysis (HEA shows that current channelling affects the electromagnetic fields in this zone and causes the anomalous direction of induction arrows. Based on the combined interpretation of GDS data from the Eastern Alps and West Hungary together with our recent data from Switzerland, the following geological implications are discussed: i a spatial decoupling of induction processes from the upper to the lower crust; ii a lower crustal conductive structure caused by the indentation of the Northern Adriatic promontory or terrane; iii the eastward continuation of the Bündnerschiefer-facies at least to the tectonic window of Rechnitz.

Entanglement versus Stosszahlansatz: disappearance of the thermodynamic arrow in a high-correlation environment.

Science.gov (United States)

Partovi, M Hossein

2008-02-01

The crucial role of ambient correlations in determining thermodynamic behavior is established. A class of entangled states of two macroscopic systems is constructed such that each component is in a state of thermal equilibrium at a given temperature, and when the two are allowed to interact heat can flow from the colder to the hotter system. A dilute gas model exhibiting this behavior is presented. This reversal of the thermodynamic arrow is a consequence of the entanglement between the two systems, a condition that is opposite to molecular chaos and shown to be unlikely in a low-entropy environment. By contrast, the second law is established by proving Clausius' inequality in a low-entropy environment. These general results strongly support the expectation, first expressed by Boltzmann and subsequently elaborated by others, that the second law is an emergent phenomenon which requires a low-entropy cosmological environment, one that can effectively function as an ideal information sink.

BIOÉTICA Y GENÓMICA BIOÉTICA E GENÔMICA BIOETHICS AND GENOMICS

Directory of Open Access Journals (Sweden)

José Alberto Mainetti

2003-01-01

Full Text Available Los avances científicos en el campo de la genómica abren las puertas a los fantasmas de la humanidad. Por esto, el Proyecto Genoma Humano (PGH ha sido el primer gran proyecto de investigación internacional que ha tenido un subproyecto sobre la problemática ética, legal y social asociada al mismo: Ethical, Legal, and Social Issues (ELSI. Esta preocupación bioética surgió como espacio de dilucidación de las diferentes preocupaciones éticas y sociales que nacían a la par de los avances de la genómica. La genómica, expresada como la clave que revelará el misterio del ser (la lámpara de Aladino o como la herramienta de destrucción ecológica, el determinismo genético, el reduccionismo genético y la eugenesia, es decir, como la caja de Pandora. El PGH posee un incalculable valor para el diagnóstico de nuevas enfermedades, nuevos fármacos y nuevas terapias, pero abre también riesgos y temores que han de ser estudiados y analizados desde una perspectiva más amplia que la científicotécnica, es decir, como una reflexión bioética sobre la genómicaOs avanços científicos no campo da genômica abrem as portas aos fantasmas da humanidade. Por isso, o Projeto Genoma Humano (PGH foi o primeiro grande projeto de pesquisa internacional que teve um subprojeto sobre a problemática ética, legal e social associada ao mesmo. Esta preocupação bioética surgiu como espaço de elucidação das diferentes preocupações éticas e sociais que surgiam ao par dos avanços da genômica. A genômica, expressa como a chave que revelará o mistério do ser ( a lâmpada de Aladim ou como a ferramenta de destruição ecológica, o determinismo gen´tico, o reducionismo genético e a eugenésia, isto é, como a caixa de Pandora. O PGH possui um incalculável valor para o diagnóstico de novas enfermidades, novos fármacos e novas terapias, porém abrem também riscos e temores que devem ser estudados e analisados numa perspectiva mais ampla que a

Atomically flat platinum films grown on synthetic mica

Science.gov (United States)

Tanaka, Hiroyuki; Taniguchi, Masateru

2018-04-01

Atomically flat platinum thin films were heteroepitaxially grown on synthetic fluorophlogopite mica [KMg3(AlSi3O10)F2] by van der Waals epitaxy. Platinum films deposited on a fluorophlogopite mica substrate by inductively coupled plasma-assisted sputtering with oxygen introduction on a synthetic mica substrate resulted in the growth of twin single-crystalline epitaxial Pt(111) films.

Malvaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Magda Chanco

2013-10-01

Full Text Available La familia Malvaceae es reconocida en el Perú con 38 géneros y 264 especies (Brako & Zarucchi 1993, Ulloa et al. 2004, mayormente arbustos y hierbas. En este trabajo reconocemos 87 especies endémicas en 16 géneros. El género más rico en especies endémicas es Nototriche. Las especies endémicas se encuentran en varias regiones ecológicas, entre ellas Altoandina, Mesoandina y Puna Húmeda y Seca, por encima de los 2500 m, hasta alcanzar los límites de la vegetación a 5100 m de altitud. Se aplicaron las categorías y criterios de la UICN a 84 especies. Once especies endémicas se encuentran presentes en el Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Vochysiaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Vochysiaceae es reconocida en el Perú por presentar cuatro géneros y 32 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, todas árboles. En este trabajo reconocemos dos especies endémicas en el género Qualea. Estas especies endémicas han sido encontradas en la región Bosques Húmedos Amazónicos, entre los 100 y 160 m de altitud. Ninguna especie endémica se encuentra representada dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

On the synchronization of identical and non-identical 4-D chaotic systems using arrow form matrix

International Nuclear Information System (INIS)

Hammami, S.; Ben Saad, K.; Benrejeb, M.

2009-01-01

Using the Borne and Gentina practical criterion associated with the Benrejeb canonical arrow form matrix, to derive the stability property of dynamic complex systems, a new strategy of control is formulated for chaos synchronization of two identical Lorenz Stenflo systems and two new four-dimensional chaotic systems, namely the Qi chaotic systems. The designed controller ensures that the state variables of both controlled chaotic slave Lorenz Stenflo and Qi systems globally synchronizes with the state variables of the master systems, respectively. It is also shown that Qi system globally synchronizes with Lorenz Stenflo system under the afforded generalized strategy of control. Numerical simulations are carried out to assess the performance of the proposed contributions in the important field of chaotic synchronization.

Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration

Science.gov (United States)

Turner, M. J.; Grande, D. L.

1978-01-01

Based on estimated graphite and boron fiber properties, allowable stresses and strains were established for advanced composite materials. Stiffened panel and conventional sandwich panel concepts were designed and analyzed, using graphite/polyimide and boron/polyimide materials. The conventional sandwich panel was elected as the structural concept for the modified wing structure. Upper and lower surface panels of the arrow wing structure were then redesigned, using high strength graphite/polyimide sandwich panels, retaining the titanium spars and ribs from the prior study. The ATLAS integrated analysis and design system was used for stress analysis and automated resizing of surface panels. Flutter analysis of the hybrid structure showed a significant decrease in flutter speed relative to the titanium wing design. The flutter speed was increased to that of the titanium design by selective increase in laminate thickness and by using graphite fibers with properties intermediate between high strength and high modulus values.

Mechanistic Indicators of Childhood Asthma (MICA) Study

Science.gov (United States)

The Mechanistic Indicators of Childhood Asthma (MICA) Study has been designed to incorporate state-of-the-art technologies to examine the physiological and environmental factors that interact to increase the risk of asthmatic responses. MICA is primarily a clinically-bases obser...

Moraceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Pamela Cáceres

2013-10-01

Full Text Available La familia Moraceae es reconocida en el Perú por presentar 19 géneros y 128 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, la mayoría arbóreas y/o hemiepífitos. En este trabajo reconocemos dos especies endémicas en igual número de géneros. Las especies endémicas se encuentran en la región Bosques Húmedos Amazónicos, entre los 115 y 220 m de altitud. Ambas especies endémicas se encuentran dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Rosaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Wilfredo Mendoza

2013-10-01

Full Text Available La familia Rosaceae es reconocida en el Perú por presentar 24 géneros y 113 especies (Brako & Zarucchi, 1993; Mendoza, 2005; Ulloa Ulloa et al., 2004, entre hierbas, arbustos y árboles. En este trabajo reconocemos 14 especies endémicas en cuatro géneros. Las especies endémicas se encuentran principalmente en las regiones Bosques Pluviales Montanos, Bosques Muy Húmedos Montanos y Páramo, entre los 1900 y 3800 m de altitud. Seis especies endémicas se encuentran representadas dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Highly charged swelling mica reduces Cu bioavailability in Cu-contaminated soils

Energy Technology Data Exchange (ETDEWEB)

Stuckey, Jason W. [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States); Neaman, Alexander [Facultad de Agronomia, P. Universidad Catolica de Valparaiso, Centro Regional de Estudios en Alimentos Saludables (Chile); Ravella, Ramesh; Komarneni, Sridhar [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States); Martinez, Carmen Enid [Department of Crop and Soil Sciences, Pennsylvania State University, 116 ASI Building, University Park, PA 16802 (United States)], E-mail: cem17@psu.edu

2009-01-15

This is the first test of a highly charged swelling mica's (Na-2-mica) ability to reduce the plant-absorbed Cu in Cu-contaminated soils from Chile. Perennial ryegrass (Lolium perenne L.) was grown in two acid soils (Sector 2: pH 4.2, total Cu = 172 mg Cu kg{sup -1} and Sector 3: pH 4.2, total Cu = 112 mg Cu kg{sup -1}) amended with 0.5% and 1% (w/w) mica, and 1% (w/w) montmorillonite. At 10 weeks of growth, both mica treatments decreased the shoot Cu of ryegrass grown in Sector 2 producing shoot Cu concentrations above 21-22 mg Cu kg{sup -1} (the phytotoxicity threshold for that species), yet the mica treatments did not reduce shoot Cu concentrations when grown in Sector 3, which were at a typical level. The mica treatments improved shoot growth in Sector 3 by reducing free and extractable Cu to low enough levels where other nutrients could compete for plant absorption and translocation. In addition, the mica treatments improved root growth in both soils, and the 1% mica treatment reduced root Cu in both soils. This swelling mica warrants further testing of its ability to assist re-vegetation and reduce Cu bioavailability in Cu-contaminated surface soils. - In situ remediation of Cu-contaminated soils with a synthetic mica (Na-2-mica) will aid in re-vegetative efforts.

DNA adsorption and desorption on mica surface studied by atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Sun Lanlan [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Graduate school of the Chinese Academy of Sciences, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022 (China); Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China); Zhao Dongxu [Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 16 East Nan-Hu Road, Open Economic Zone, Changchun 130033 (China); Zhang Yue; Xu Fugang [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Graduate school of the Chinese Academy of Sciences, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022 (China); Li Zhuang, E-mail: zli@ciac.jl.cn [State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Graduate school of the Chinese Academy of Sciences, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022 (China)

2011-05-15

The adsorption of DNA molecules on mica surface and the following desorption of DNA molecules at ethanol-mica interface were studied using atomic force microscopy. By changing DNA concentration, different morphologies on mica surface have been observed. A very uniform and orderly monolayer of DNA molecules was constructed on the mica surface with a DNA concentration of 30 ng/{mu}L. When the samples were immersed into ethanol for about 15 min, various desorption degree of DNA from mica (0-99%) was achieved. It was found that with the increase of DNA concentration, the desorption degree of DNA from the mica at ethanol-mica interface decreased. And when the uniform and orderly DNA monolayers were formed on the mica surface, almost no DNA molecule desorbed from the mica surface in this process. The results indicated that the uniform and orderly DNA monolayer is one of the most stable DNA structures formed on the mica surface. In addition, we have studied the structure change of DNA molecules after desorbed from the mica surface with atomic force microscopy, and found that the desorption might be ascribed to the ethanol-induced DNA condensation.

DNA adsorption and desorption on mica surface studied by atomic force microscopy

International Nuclear Information System (INIS)

Sun Lanlan; Zhao Dongxu; Zhang Yue; Xu Fugang; Li Zhuang

2011-01-01

The adsorption of DNA molecules on mica surface and the following desorption of DNA molecules at ethanol-mica interface were studied using atomic force microscopy. By changing DNA concentration, different morphologies on mica surface have been observed. A very uniform and orderly monolayer of DNA molecules was constructed on the mica surface with a DNA concentration of 30 ng/μL. When the samples were immersed into ethanol for about 15 min, various desorption degree of DNA from mica (0-99%) was achieved. It was found that with the increase of DNA concentration, the desorption degree of DNA from the mica at ethanol-mica interface decreased. And when the uniform and orderly DNA monolayers were formed on the mica surface, almost no DNA molecule desorbed from the mica surface in this process. The results indicated that the uniform and orderly DNA monolayer is one of the most stable DNA structures formed on the mica surface. In addition, we have studied the structure change of DNA molecules after desorbed from the mica surface with atomic force microscopy, and found that the desorption might be ascribed to the ethanol-induced DNA condensation.

La Industria Química: Importancia y Retos

Directory of Open Access Journals (Sweden)

Nancy Montes-Valencia

2015-06-01

Full Text Available La química siempre ha estado presente en la vida del hombre para satisfacer sus necesidades y mejorar su calidad de vida. Hoy en día la industria química es un importante sector industrial presente en la mayoría de países, que dinamiza el crecimiento económico, genera empleo y ofrece diversidad de productos, no obstante produce contaminación al medio ambiente y utiliza recursos naturales no renovables. Por lo tanto surge el concepto de química verde como respuesta a la problemática ambiental cuya estructura es la sostenibilidad, siendo su principal objetivo prevenir la generación de emisiones y armonizar la química con los recursos naturales. Existe un gran reto para la industria química y es encontrar fuentes alternativas de energía para no seguir dependiendo del petróleo, el gas natural y el carbón, una de estas es el uso de la biomasa para la obtención de combustibles líquidos.

“Nadie es profeta en su tierra”: Etnografía económica de las dinámicas comerciales de los Kichwa-Otavalo en San Victorino, Bogotá

OpenAIRE

López Ávila, Diego Felipe

2015-01-01

La presente monografía describe las dinámicas económicas de los Kichwas Otavalo en la zona comercial de San Victorino, Bogotá. Dichas dinámicas son examinadas a partir de la Nueva Sociología Económica (Smelser & Swedberg, 2005) y la Etnografía Económica (Dufy & Weber, 2009) para mostrar las divergentes racionalidades que surgen al interior del mercado. Esto nos lleva a debatir con la ciencia económica ortodoxa y los supuestos que manejan frente a la racionalidad, el mercado y la competencia....

Optimized-geometry ARROW waveguides using TiO{sub 2} as anti-resonant layer

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Daniel O.; Albertin, Katia F.; Alayo, Marco I. [PSI, University of Sao Paulo (Brazil)

2010-04-15

The simulation, fabrication and characterization of ARROW waveguides using dielectric films deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) and Sputtering techniques, are presented in this work. Amorphous titanium oxide (TiO{sub 2}) films were used as first cladding layer and silicon oxynitride (SiO{sub x}N{sub y}) films, as core layer. Furthermore, homemade routines based in two computational methods were used, for numerical simulations: Transfer Matrix Method (TMM) for the determination of the optimum thickness values of the Fabry-Perot layers, and the Finite Difference Method (FDM) for 2D design and determination of the maximum width that allows single-mode operation. The utilization of thermally grown silicon oxide as second anti-resonant layer, along with improvements in the Reactive Ion Etching conditions for the definition of sidewalls of the optical waveguides were responsible for diminishing optical attenuations. Optimization of the waveguide rib height was done both through FDM simulations and experimentally. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Onagraceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Susy Castillo

2013-10-01

Full Text Available Esta es la familia de las «fucsias», la cual es reconocida en el Perú por presentar seis géneros y 76 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, principalmente arbustos y hierbas. En este trabajo reconocemos 24 especies endémicas, la mayoría en el género Fuchsia. Las especies endémicas se encuentran mayormente en la región Bosques Muy Húmedos Montanos, entre los 1600 y 2500 m de altitud. Diez especies endémicas se encuentran representados dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Competitividad Sistémica. Niveles analíticos para el fortalecimiento de sectores de actividad económica

Directory of Open Access Journals (Sweden)

Juliana Ferrer

2005-01-01

Full Text Available Un desarrollo industrial exitoso no se logra meramente considerando la función de producción en el nivel microeconómico, o las condiciones macroeconómicas estables; sino también por la existencia de medidas específicas del gobierno y de organizaciones privadas de desarrollo, orientadas a fortalecer la competitividad de los sectores de actividad económica. Además, la capacidad de vincular las iniciativas, está en función de un conjunto de estructuras político- económicas y de factores socioculturales y patrones básicos de organización, que caracterizan el proceso sistémico de competitividad de cada país. Se concluye que existe una marcada desarticulación entre los niveles de competitividad sistémica; reflejada por una incoherencia entre las políticas de Estado, los requerimientos de sectores de actividad y el reflejo de la necesidad real de las comunidades cada vez más desprovistas de recursos. Se recomienda la necesidad de superar la ardua fase que representa establecer una economía de mercado dirigida a mejorar la condición de vida de la población; por lo que será importante facilitar procesos autónomos de búsqueda y aprendizaje significativos, para el desarrollo de la competitividad de los sectores de actividad económica latinoamericanos.

APRENDIENDO ELECTROQUÍMICA. UN ESTUDIO COMPARATIVO

Directory of Open Access Journals (Sweden)

Maria I. Vera

2011-01-01

Full Text Available Se realizó un seguimiento del proceso de enseñanza y aprendizaje de Electroquímica y se compararon los resultados obtenidos en evaluaciones parciales, con el objetivo de analizar si existen diferencias significativas en la apropiación de contenidos entre alumnos de carreras con diferentes perfiles. Se trabajó en los años 2009 y 2010 con dos grupos de alumnos en cada año, pertenecientes a carreras químicas y no químicas respectivamente. En ambos grupos se desarrollaron, con la misma carga horaria, contenidos conceptuales y procedimentales en clases teóricas con prácticas de resolución de problemas y de laboratorio. Para la evaluación se presentaron idénticas situaciones problemáticas, cuyos resultados muestran diferencias no significativas entre ambos grupos en la identificación del cátodo y del ánodo y cálculo de la fem estándar de la celda; en cambio en la aplicación de la Ecuación de Nernst y la identificación de especies químicas que reaccionan en los electrodos, hay diferencias significativas en las respuestas dadas.

DNA → RNA: What Do Students Think the Arrow Means?

Science.gov (United States)

Wright, L Kate; Fisk, J Nick; Newman, Dina L

2014-01-01

The central dogma of molecular biology, a model that has remained intact for decades, describes the transfer of genetic information from DNA to protein though an RNA intermediate. While recent work has illustrated many exceptions to the central dogma, it is still a common model used to describe and study the relationship between genes and protein products. We investigated understanding of central dogma concepts and found that students are not primed to think about information when presented with the canonical figure of the central dogma. We also uncovered conceptual errors in student interpretation of the meaning of the transcription arrow in the central dogma representation; 36% of students (n = 128; all undergraduate levels) described transcription as a chemical conversion of DNA into RNA or suggested that RNA existed before the process of transcription began. Interviews confirm that students with weak conceptual understanding of information flow find inappropriate meaning in the canonical representation of central dogma. Therefore, we suggest that use of this representation during instruction can be counterproductive unless educators are explicit about the underlying meaning. © 2014 L. K. Wright et al. CBE—Life Sciences Education © 2014 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Absolute becoming, relational becoming and the arrow of time: Some non-conventional remarks on the relationship between physics and metaphysics

Science.gov (United States)

Dorato, Mauro

The literature on the compatibility between the time of our experience-characterized by passage or becoming-and time as is represented within spacetime theories has been affected by a persistent failure to get a clear grasp of the notion of becoming, both in its relation to an ontology of events "spread" in a four-dimensional manifold, and in relation to temporally asymmetric physical processes. In the first part of my paper I try to remedy this situation by offering what I consider a clear and faithful explication of becoming, valid independently of the particular spacetime setting in which we operate. Along the way, I will show why the metaphysical debate between the so-called "presentists" and "eternalists" is completely irrelevant to the question of becoming, as the debate itself is generated by a failure to distinguish between a tensed and a tenseless sense of "existence". After a much needed distinction between absolute and relational becoming, I then show in what sense classical (non-quantum) spacetime physics presupposes both types of becoming, for the simple reason that spacetime physics presupposes an ontology of (timelike-separated) events. As a consequence, not only does it turn out that using physics to try to provide empirical evidence for the existence of becoming amounts to putting the cart before the horses, but also that the order imposed by "the arrow of becoming" is more fundamental than any other physical arrow of time, despite the fact that becoming cannot be used to explain why entropy grows, or retarded electromagnetic radiation prevails versus advanced radiation.

Preparation of mica/apatite glass-ceramics biomaterials

International Nuclear Information System (INIS)

Liu Yong; Sheng Xiaoxian; Dan Xiaohong; Xiang Qijun

2006-01-01

Glass-ceramics have become more and more important biomaterials. In this work mica glass/apatite composites with various compositions were prepared by casting and subsequent heat treatments. The effects of composition, phase constitution and crystallinity on mechanical properties, including elastic modulus and transverse rupture strength (TRS), were investigated by using X-ray diffraction analyses (XRD), scanning electron microscopy (SEM) and mechanical tests. Results show that addition of apatite composition in mica glass accelerates the crystallization process and induces the formation of fluoroapatite phase, and the nucleation of apatite crystals occurs before that of mica crystals. The fuoroapatite in this work is needle-like, which is almost the same to that in human bone. The transverse rupture strength increases with the content of fluoroapatite and the crystallinity increasing, except that at a low apatite content the mechanical properties are lower than those of mica glass under the same processing conditions. The transverse rupture strength and elastic modulus obtained in this work fall in the range of those of human bone. SBF immersion test demonstrates good bioactivity of this biomaterial

Trayectorias evolucionistas en la dinámica de la empresa: una aproximación por dinámica de sistemas

Directory of Open Access Journals (Sweden)

Germán Eduardo Vargas

2006-05-01

Full Text Available La actividad de las firmas, como unidad socioeconómica, en el marco evolucionista está orientada integralmente por procesos de identidad, cohesión y mecanismos de adaptación y evolución; en este orden, el presente documento ilustra, a través de un modelo por dinámica de sistemas, cómo la orientación e integración estratégica basada en el conocimiento para la innovación se constituye como un imperativo de desarrollo que, a partir de un pequeño apalancamiento, permite distinguir entre dos trayectorias de evolución, a saber: firmas económicas tradicionales (inerciales, pues introducen mejoras incrementales esporádicas y modernas (dinámicas y radicalmente innovadoras, hecho a partir del cual se obtienen reveladoras conclusiones y desafíos para intervenir y adecuar el comportamiento de las empresas.2

Study of the Decay {ital {tau}}{sup {minus}}{r_arrow}2{ital {pi} }{sup {minus}}{ital {pi}}{sup +} 3{ital {pi}}{sup 0}{ital {nu}}{sub {ital {tau} }}

Energy Technology Data Exchange (ETDEWEB)

Anderson, S.; Kubota, Y.; Lee, S. .; ONeill, J.J.; Patton, S.; Poling, R.; Riehle, T.; Savinov, V.; Smith, A. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Severini, H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Duboscq, J.E.; Fujino, D.; Gan, K.K.; Hart, T.; Homoelle, D.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M.M. [The Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; Yurko, M. [Purdue University, West Lafayette, Indiana 47907 (United States); Gibbons, L.; Glenn, S.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Ugolini, D.; Wang, R.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Shelkov, V.; Staeck, J.; Stroynowski, R.; Volobouev, I.; Ye, J. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Efimov, A.; Goldberg, M.; He, D.; Kopp, S.; Moneti, G.C.; Mountain, R.; Schuh, S.; Skwarnicki, T.; Stone, S.; Viehhauser, G.; Xing, X. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; Jain, V.; McLean, K.W.; Marka, S. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Godang, R.; Kinoshita, K.; Lai, I.C.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Bonvicini, G.; Cinabro, D.; Greene, R.; and others

1997-11-01

The decay {tau}{sup {minus}}{r_arrow}2{pi}{sup {minus}}{pi}{sup + }3{pi}{sup 0}{nu}{sub {tau}} has been studied with the CLEOII detector at the Cornell Electron Storage Ring. The branching fraction is measured to be (2.85{plus_minus}0.56{plus_minus}0.51){times}10{sup {minus}4} . The result is in good agreement with the isospin expectation but somewhat below the conserved-vector-current prediction. We have searched for resonance substructure in the decay. Within the statistical precision, the decay is saturated by the channels {tau}{sup {minus}}{r_arrow}{pi}{sup {minus}}2{pi}{sup 0 }{omega}{nu}{sub {tau}} , 2{pi}{sup {minus}}{pi}{sup +}{eta}{nu}{sub {tau}} , and {pi}{sup {minus}}2{pi}{sup 0}{eta}{nu}{sub {tau}} . This is the first observation of this {omega} decay mode and the branching fraction is measured to be (1.89{sup +0.74}{sub {minus}0.67}{plus_minus}0.40) {times}10{sup {minus}4} . {copyright} {ital 1997} {ital The American Physical Society}

Major histocompatibility complex class I-related chain A/B (MICA/B) expression in tumor tissue and serum of pancreatic cancer: Role of uric acid accumulation in gemcitabine-induced MICA/B expression

International Nuclear Information System (INIS)

Xu, Xiulong; Rao, Geetha S; Groh, Veronika; Spies, Thomas; Gattuso, Paolo; Kaufman, Howard L; Plate, Janet; Prinz, Richard A

2011-01-01

Major histocompatibility complex class I-related chain A and B (MICA/B) are two stress-inducible ligands that bind the immunoreceptor NKG2D and play an important role in mediating the cyotoxicity of NK and T cells. In this study, we sought to study MICA/B expression in pancreatic cancer and to determine whether and how genotoxic drugs such as gemcitabine can affect MICA/B expression and natural killer cytotoxity. Seven pancreatic cancer cell lines were analyzed for MICA/B expression by flow cytometry and for their sensitivity to NK-92 cell killing by a 51 Cr release assay. MICA/B expression in tumor tissues and sera of pancreatic cancer was analyzed by immunohistochemical staining (IHC) and ELISA, respectively. Two MICA/B-positive cell lines were sensitive to the cytotoxic activity of NK-92 cells. Other two MICA/B-positive cell lines and three MICA/B-negative cell lines were resistant to NK-92 cell killing. MICA/B expression was positive in 17 of 25 (68%) pancreatic ductal adenocarcinomas but not in normal pancreatic ductal epithelial cells. Serum MICA/B levels were significantly elevated in patients with pancreatic adenocarcinomas but did not correlate with the stage of pancreatic cancer and patient survival. Gemcitabine therapy led to increased serum MICA levels in 6 of 10 patients with detectable serum MICA. Allopurinol, an inhibitor of xanthine oxidoreductase that converts xanthine to uric acid, blocked uric acid production, MICA/B expression, and sensitivity to NK-92 cell killing toward a PANC-1 cancer cell line exposed to radiation and two genotoxic drugs, gemcitabine and 5-fluorouracil. The levels of MICA/B expression in serum and tissue of pancreatic cancer are elevated. DNA damage-induced MICA/B expression is mediated through increased uric acid production

Major histocompatibility complex class I-related chain A/B (MICA/B expression in tumor tissue and serum of pancreatic cancer: Role of uric acid accumulation in gemcitabine-induced MICA/B expression

Directory of Open Access Journals (Sweden)

Kaufman Howard L

2011-05-01

Full Text Available Abstract Background Major histocompatibility complex class I-related chain A and B (MICA/B are two stress-inducible ligands that bind the immunoreceptor NKG2D and play an important role in mediating the cyotoxicity of NK and T cells. In this study, we sought to study MICA/B expression in pancreatic cancer and to determine whether and how genotoxic drugs such as gemcitabine can affect MICA/B expression and natural killer cytotoxity. Methods Seven pancreatic cancer cell lines were analyzed for MICA/B expression by flow cytometry and for their sensitivity to NK-92 cell killing by a 51Cr release assay. MICA/B expression in tumor tissues and sera of pancreatic cancer was analyzed by immunohistochemical staining (IHC and ELISA, respectively. Results Two MICA/B-positive cell lines were sensitive to the cytotoxic activity of NK-92 cells. Other two MICA/B-positive cell lines and three MICA/B-negative cell lines were resistant to NK-92 cell killing. MICA/B expression was positive in 17 of 25 (68% pancreatic ductal adenocarcinomas but not in normal pancreatic ductal epithelial cells. Serum MICA/B levels were significantly elevated in patients with pancreatic adenocarcinomas but did not correlate with the stage of pancreatic cancer and patient survival. Gemcitabine therapy led to increased serum MICA levels in 6 of 10 patients with detectable serum MICA. Allopurinol, an inhibitor of xanthine oxidoreductase that converts xanthine to uric acid, blocked uric acid production, MICA/B expression, and sensitivity to NK-92 cell killing toward a PANC-1 cancer cell line exposed to radiation and two genotoxic drugs, gemcitabine and 5-fluorouracil. Conclusions The levels of MICA/B expression in serum and tissue of pancreatic cancer are elevated. DNA damage-induced MICA/B expression is mediated through increased uric acid production.

Strong association between a splice mutation (IVS12+5G{r_arrow}A) and haplotype 6 in hereditary tyrosinemia type I

Energy Technology Data Exchange (ETDEWEB)

Tanguay, R.M.; St-Louis, M.; Gibson, K. [Universite Laval, Ste-Foy (Canada)] [and others

1994-09-01

Hereditary tyrosinemia type I (HT I; McKusick 276700) is a severe inborn error of tyrosine catabolism pathway caused by a deficiency of fumarylacetoacetate hydrolase (FAH). The highest frequency reported is the one in Saguenay-Lac St-Jean (Quebec, Canada) where 1:1,846 births are affected. The FAH gene has been cloned and several mutations have been described. Allele specific oligonucleotide (ASO) hybridization was used to examine the frequency of a splice (IVS12-5G{r_arrow}A) mutation recently reported and RFLP analysis was done to identify haplotypes related to HT I. The splice mutation was found on 45/50 alleles (90%) in patients from SLSJ and 12/66 (18%) alleles from patients world-wide. All 25 patients from the SLSJ region were positive with 20 being homozygous, indicating that this mutation is the major cause of HT I in French Canada. Of these 25 patients, 96% were positive for one haplotype called no 6 which is these 25 patients, 96% were positive for one haplotype called no 6 which is identified by TaqI, RsaI, BglII, MspI and KpnI digestions. These data show a really strong association between the mutation (IVS12+5G{r_arrow}A) and haplotype 6. Among our patients from around the world, {approximately}52% were positive for haplotype 6 indicating its strong relation with HT I. These results provide the rationale for DNA-based carrier testing for HT I in the F-C population at risk as well as in HT I patients in general.

Algunas reflexiones sobre la distancia entre "hablar química" y "comprender química"

Directory of Open Access Journals (Sweden)

Lydia Raquel Galagovsky

2014-12-01

Full Text Available Una clase de química puede ser considerada como un espacio de comunicación entre el docente experto y los estudiantes novatos, donde los lenguajes utilizados son la interfase explícita y observable del intercambio comunicativo. En el presente trabajo se muestra con dos ejemplos cómo la diversidad de lenguajes químicos en lugar de favorecer la comprensión de los estudiantes, puede actuar como fuente de obstáculos que dificultan la comunicación en el aula. Así mismo, se analizará con otros dos ejemplos cómo el discurso con el que se enseña la disciplina también es potencial generador de errores en los estudiantes, cuando ellos construyen sus modelos mentales idiosincrásicos a partir de un discurso recortado y simplificado, desde las mejores intenciones de realizar buenas transposiciones didácticas. Se plantea que un enfoque de análisis de la situación de aula como un encuentro comunicativo entre experto y novato conduce a una necesaria diferenciación entre "hablar química" y "comprender química".

Preparation and characterization of aluminum based alloy - mica composites

International Nuclear Information System (INIS)

Rashid, M.A.; Shamim, A.

1999-01-01

In this work, six pallets each of 2.0 cm dia and 0.5 cm thickness were prepared by powder metallurgy; half of them also contained 1% mica-powder to form a composite. Inclusion of mica resulted in a decreased density and an increased porosity of the sample. Brinell hardness was found to be 21% less for the composite than for the pure alloy. Micro-graphs of different areas of the sample show uniform distribution of mica particles and avoids around them. (author)

Microstructures and luminescent properties of Ce-doped transparent mica glass-ceramics

International Nuclear Information System (INIS)

Taruta, Seiichi; Iwasaki, Yoshitomo; Nishikiori, Hiromasa; Yamakami, Tomohiko; Yamaguchi, Tomohiro; Kitajima, Kunio; Okada, Kiyoshi

2012-01-01

Highlights: ► Ce-doped transparent glass-ceramics and their parent glasses. ► TEM and STEM images for the microstructures. ► Each mica crystal did not contain Ce uniformly. ► Emission due to Ce 3+ ions in the glass phase and/or Ce 3+ ions in the mica crystals. - Abstract: Transparent mica glass-ceramics were prepared by heating parent glasses that had been doped with 0.5–15 mol% CeO 2 . During the melting and heat treatment, Ce 4+ ions in the specimens were reduced to Ce 3+ ions, and one or both of these ion species were then replaced with Li + ions in the interlayers of the separated mica crystals. However, scanning transmission electron microscope (STEM) and Z-contrast imaging revealed that the mica crystals did not contain the same amount of Ce. On excitation at 254 nm, the parent glasses and glass-ceramics emitted blue light, which originated from the 5d to 4f transition of the Ce 3+ ions. The emission of the glass-ceramic containing a smaller amount of Ce was attributed to the Ce 3+ ions in both the glass phase and the mica crystals, whereas that of the glass-ceramics containing a larger amount of Ce was caused mainly by Ce 3+ ions in the mica crystals. The dependence of the emission band of the parent glasses on the amount of Ce was a unique feature of the Ce-doped transparent mica glass-ceramics and was not observed in previous studies of Eu-doped parent glasses and mica glass-ceramics.

Gentianaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Susy Castillo

2013-10-01

Full Text Available La familia Gentianaceae es reconocida en el Perú por presentar alrededor de 15 géneros y aproximadamente de 170 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004; S. Castillo, com.pers., mayormente hierbas y arbustos. En este trabajo se reconoce 103 especies endémicas en siete géneros. Los géneros con mayor número de especies endemicas son Gentianella y Macrocarpaea. Las especies endémicas ocupan principalmente las regiones de la Puna Húmeda y Seca, Páramo y Bosque Muy Húmedo Montano, entre los 1000 y 5100 m de altitud. Se aplicaron las categorías y criterios de la UICN a 99 especies. Treinta y tres especies endémicas se encuentran representadas dentro de un área protegida.

Form factor ratio measurement in {Lambda}{sup +}{sub {ital c}}{r_arrow}{Lambda}{ital e}{sup +}{nu}{sub {ital e}}

Energy Technology Data Exchange (ETDEWEB)

Crawford, G.; Daubenmier, C.M.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Sung, M.; White, C.; Wolf, A.; Zoeller, M.M.; Butler, F.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; Hinson, J.W.; McIlwain, R.L.; Miao, T.; Miller, D.H.; Modesitt, M.; Payne, D.; Shibata, E.I.; Shipsey, I.P.J.; Wang, P.N.; Battle, M.; Ernst, J.; Gibbons, L.; Kwon, Y.; Roberts, S.; Thorndike, E.H.; Wang, C.H.; Dominick, J.; Lambrecht, M.; Sanghera, S.; Shelkov, V.; Skwarnicki, T.; Stroynowski, R.; Volobouev, I.; Wei, G.; Zadorozhny, P.; Artuso, M.; Gao, M.; Goldberg, M.; He, D.; Horwitz, N.; Moneti, G.C.; Mountain, R.; Muheim, F.; Mukhin, Y.; Playfer, S.; Rozen, Y.; Stone, S.; Xing, X.; Zhu, G.; Bartelt, J.; Csorna, S.E.; Egyed, Z.; Jain, V.; Gibaut, D.; Kinoshita, K.; Pomianowski, P.; Barish, B.; Chadha, M.; Chan, S.; Cowen, D.F.; Eigen, G.; Miller, J.S.; O`Grady, C.; Urheim, J.; Weinstein, A.J.; Athanas, M.; Brower, W.; Masek, G.; Paar, H.P.; Gronberg, J.; Korte, C.M.; Kutschke, R.; Menary, S.; Morrison, R.J.; Nakanishi, S.; Nelson, H.N.; Nelson, T.K.; Qiao, C.; Richman, J.D.; Ryd, A.; Sperka, D.; Tajima, H.; Witherell, M.S.; Procario, M.; Balest, R.; Cho, K.; Ford, W.T.; Johnson, D.R.; Lingel, K.; Lohner, M.; Rankin, P.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berkelman, K.; Bloom, K.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Drell, P.S.; Dumas, D.J.; Ehrlich, R.; Gaidarev, P.; Garcia-Sciveres, M.; Geiser, B.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Patterson, J.R.; Peterson, D.; Riley, D.; Salman, S.; Sapper, M.; Wuerthwein, F.; Avery, P.; Freyberger, A.; Rodriguez, J.; Yang, S.; Yelton, J.; Cinabro, D.; Liu, T.; Saulnier, M.; Wilson, R.; Yamamoto, H.; Bergfeld, T.; (CLEO Collaboration)

1995-07-24

The angular distributions of the decay {Lambda}{sup +}{sub {ital c}}{r_arrow}{Lambda}{ital e}{sup +}{nu}{sub {ital e}} have been studied using the CLEO II detector. By performing a three-dimensional maximum likelihood fit, the form factor ratio {ital R}={ital f}{sub 2}/{ital f}{sub 1} is determined to be {minus}0.25{plus_minus}0.14{plus_minus}0.08. The decay asymmetry parameter of the {Lambda}{sub {ital c}} averaged over {ital q}{sup 2} is calculated to be {alpha}{sub {Lambda}{sub {ital c}}}={minus}0.82{sub {minus}0.06{minus}0.03}{sup +0.09+0.06}.

Química de Heterociclos. Quinolina e isoquinolina

OpenAIRE

Collado, Daniel

2014-01-01

Quinolinas e isoquinolinas: propiedades. Reactividad química: SEAr, SNAr. Reacciones en cadenas laterales. Reacciones de quinolinio e isoquinolinio. Síntesis de quinolinas e isoquinolinas. Otros ciclos. Capítulo sexto de temario de la Asignatura Ampliación de Química Orgánica Avanzada. Quinolina e isoquinolina.

ANALOGIAS EM LIVROS DIDÁTICOS DESTINADOS AO ENSINO SUPERIOR: QUÍMICA ORGÂNICA VERSUS FÍSICO-QUÍMICA

Directory of Open Access Journals (Sweden)

Josué Martins Gonçalves

2016-12-01

Full Text Available Os livros didáticos de Química, via de regra, fazem uso de analogias por se tratar de uma disciplina que envolve inúmeros conceitos abstratos. No entanto, há pouca pesquisa envolvendo identificação e explicação sobre as analogias utilizadas em livros didáticos direcionados ao ensino superior. Nesse sentido, o presente trabalho apresenta um estudo comparativo entre as analogias encontradas em livros de Química Orgânica e Físico-química destinados a estudantes do ensino superior. Foram identificadas 277 analogias nos livros analisados e categorizadas conforme sistemas adaptados de Thiele e Treagust (1994 e Francisco Junior (2009.Uma forma de abordagem mais adequada de utilização das analogias nesses livros foi realizada, bem como a verificação da importância do papel dos professores no uso desse recurso didático. Os resultados indicam que esses livros são ricos em analogias simples, dando ênfase às análogos estruturais no caso de livros de Química Orgânica e análogos funcionais nos de Físico-Química. As analogias simples são mais fáceis de induzirem os alunos a erros conceituais, pois mostram poucas similaridades entre os domínios comparados. É importante ressaltar que nesta pesquisa observa-se uma baixa ocorrência de analogias em que o autor do livro reconhece as limitações e/ou discute estas, repassando toda a responsabilidade ao professor e ao aluno no que se refere à explicação e percepção das analogias, respectivamente. É mister afirmar que muitas das analogias encontradas em alguns capítulos dos livros analisados, poderiam ser suprimidas sem perda significativa da compreensão dos conceitos abordados.

CONFLICTO, VIOLENCIA SOCIOECONÓMICA Y DESPLAZAMIENTO FORZADO EN COLOMBIA

Directory of Open Access Journals (Sweden)

Andrés Felipe Mora Cortés

2013-12-01

Full Text Available Este artículo introduce el concepto de violencia socioeconómica, que se refiere a mecanismos de regulación de conflictos distributivos y prácticas gubernamentales que eliminan las condiciones base para la reproducción de la vida. Se identifican tres expresiones clave de la violencia socioeconómica: el despojo, la inseguridad económica y la no generación de oportunidades. El artículo insiste en el efecto desproporcionado que dichas expresiones de violencia socioeconómica tienen sobre la población desplazada; también defiende la necesidad de una agenda mínima que erradique la violencia como lógica reguladora de los conflictos distributivos y que sirva de base para la construcción de paz con justicia social en Colombia.

Moessbauer spectra of white micas from the Central Western Carpathians Mountains

International Nuclear Information System (INIS)

Sitek, J; Toth, I; Sulak, M; Putis, M

2010-01-01

Potassium white micas from the rocks included into Cretaceous deformation zones (ca. 100-70 Ma in age) of the Central Western Carpathians were investigated by Moessbauer spectroscopy. White micas formed during a polystage evolution and changing P-T conditions of their crystallization in crustal-scale shear zones. We found criteria for distinguishing generations of celadonite-poor (muscovitic) and celadonite-rich (phengitic) white micas using Moessbauer spectroscopy. This method revealed contrasting spectra characterized by typical quadrupole doublets corresponding to Fe 2+ Fe 3+ contents in white micas. They are in the range of 2.9-3.0 mm/s for phengite, and 2.6-2.7 mm/s for muscovite. Moessbauer spectra reflect well the chemical changes in white mica aggregates, especially of those close to the end-member muscovite and (alumino-)celadonite compositions.

Moessbauer spectra of white micas from the Central Western Carpathians Mountains

Energy Technology Data Exchange (ETDEWEB)

Sitek, J; Toth, I [Department of Nuclear Physics and Technology, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, Bratislava (Slovakia); Sulak, M; Putis, M, E-mail: jozef.sitek@stuba.s [Department of of Mineralogy and Petrology, Faculty of Natural Sciences, Comenius University Bratislava, Mlynska dolina G, 842 15 Bratislava (Slovakia)

2010-03-01

Potassium white micas from the rocks included into Cretaceous deformation zones (ca. 100-70 Ma in age) of the Central Western Carpathians were investigated by Moessbauer spectroscopy. White micas formed during a polystage evolution and changing P-T conditions of their crystallization in crustal-scale shear zones. We found criteria for distinguishing generations of celadonite-poor (muscovitic) and celadonite-rich (phengitic) white micas using Moessbauer spectroscopy. This method revealed contrasting spectra characterized by typical quadrupole doublets corresponding to Fe{sup 2+} Fe{sup 3+} contents in white micas. They are in the range of 2.9-3.0 mm/s for phengite, and 2.6-2.7 mm/s for muscovite. Moessbauer spectra reflect well the chemical changes in white mica aggregates, especially of those close to the end-member muscovite and (alumino-)celadonite compositions.

Prognostic value of MICA/B in cancers: a systematic review and meta-analysis.

Science.gov (United States)

Zhao, Yijing; Chen, Naifei; Yu, Yu; Zhou, Lili; Niu, Chao; Liu, Yudi; Tian, Huimin; Lv, Zheng; Han, Fujun; Cui, Jiuwei

2017-11-10

MHC class I chain related-proteins A (MICA) and B (MICB) are natural killer group 2D ligands that mediate tumor surveillance. Several studies have suggested that MICA/B levels predict clinical outcomes in patients with cancer; however, this remains contentious. Here, we present a systematic review and meta-analysis of available studies of the prognostic value of MICA/B in cancer. We searched PubMed, Embase, Clinicaltrials.gov, and Cochrane Library to identify studies published from inception to July 2017 that assessed MICA/B in patients with cancer. The hazard ratio (HR) and 95% confidence interval (CI) of MICA/B were extracted for overall survival (OS) analysis. A total of 19 studies comprising 2,588 patients with 10 different types of cancer were included in the study. Low sMICA/B levels were found associated with significantly longer OS (HR = 1.65, 95% CI [1.42-1.92], P < 0.00001). Patients with cancers of digestive system that exhibited high MICA/B expression had significantly longer OS in (HR = 0.56, 95% CI [0.39-0.80], P = 0.002) compared with those with lower MICA/B expression ( I 2 = 35%, P = 0.18). Serum soluble MICA/B represents a potential prognostic marker in various human cancers. High cell-surface MICA/B expression in cancers of the digestive system was found associated with increased survival.

Phyllitic minerals in hydrothermal uranium deposits. I. Crystalchemistry of relict and newly formed micas

International Nuclear Information System (INIS)

Leroy, Jacques; Cathelineau, Michel

1982-01-01

Several generations of white micas have been recognised in four two mica granite massifs which are associated with uranium deposits in the Hercynian chain. These different generations correspond to distinct geological phenomena belonging to the deuteric and hydrothermal stages of the history of these massifs. Crystalchemical studies of these micas with the aid of the electronic microprobe show that each of these phenomena corresponds a phengite of different, well defined compositions. An increase in the phengitic character and a decrease in the paragonite component are observed over time. Strong similarities exist between micas of the same generation belonging to different granite massifs. The study of the evolution of the earliest deuteric micas during later hydrothermal phenomena, mica episyenitisation and deposition of pitchblende, has shown two opposed trends. In the case of mica episyenitisation, the micas tend to reequilibrate, while in the case of pitchblende deposition and the vein stage in general, the micas preserve their primary character [fr

Graphene Visualizes the Ion Distribution on Air-Cleaved mica

NARCIS (Netherlands)

Bampoulis, Pantelis; Sotthewes, Kai; Siekman, Martin Herman; Zandvliet, Henricus J.W.; Poelsema, Bene

2017-01-01

The distribution of potassium (K+) ions on air-cleaved mica is important in many interfacial phenomena such as crystal growth, self-assembly and charge transfer on mica. However, due to experimental limitations to nondestructively probe single ions and ionic domains, their exact lateral organization

Effect of Mica and Hematite (001) Surfaces on the Precipitation of Calcite

OpenAIRE

Huifang Xu; Mo Zhou; Yihang Fang; H. Henry Teng

2018-01-01

The substrate effect of mica and hematite on the nucleation and crystallization of calcite was investigated using scanning electron microscope (SEM), X-ray diffraction (XRD), and electron backscatter diffraction (EBSD) methods. On mica, we found, in the absence of Mg2+, the substrates’ (001) surfaces with hexagonal and pseudo-hexagonal two-dimensional (2-D) structure can affect the orientation of calcite nucleation with calcite (001) ~// mica (001) and calcite (010) ~// mica (010) to be the m...

PLACAS CERÂMICAS - UMA INTRODUÇÃO

Directory of Open Access Journals (Sweden)

Carlos Maurício F. Vieira

2010-05-01

Full Text Available Este trabalho tem por objetivo apresentar uma revisão geral sobre as principais características exigidas para a obtenção de placas cerâmicas (pisos e revestimentos. As principais rotas de processamento são discutidas. Dados de mercado são apresentados com a finalidade de mostrar a importância e a situação atual da indústria cerâmica nacional no setor de pisos e revestimentos.

TICs en la enseñanza de la Química: Propuesta de evaluación de Laboratorios Virtuales de Química (LVQs

Directory of Open Access Journals (Sweden)

Cataldi, Zulma

2012-01-01

Full Text Available Los LVQs son unas nuevas formas de enseñanza de la química a través del uso de TICs. En este contexto se presenta el relevamiento de los laboratorios virtuales de química (LVQs más apropiados para la enseñanza de la química. Se analizan las ventajas de su aplicación en química básica y se delinean las pautas para su evaluación y selección de acuerdo a los indicadores propuestos, articulados con el marco teórico y con las dimensiones de análisis. Se propone una evaluación centrada en tres ejes: a dimensiones tecnológicas y técnicas, b dimensiones pedagógicas y c otras dimensiones como costo y comercialización. Se realizan pruebas de ajuste y aplicación del instrumento según los siguientes objetivos: a Analizar las estrategias didácticas docentes y la percepción en el uso de las TICs y b Delinear acciones formativas en didáctica de la química con uso de TICs.

Effect of Mica and Hematite (001 Surfaces on the Precipitation of Calcite

Directory of Open Access Journals (Sweden)

Huifang Xu

2018-01-01

Full Text Available The substrate effect of mica and hematite on the nucleation and crystallization of calcite was investigated using scanning electron microscope (SEM, X-ray diffraction (XRD, and electron backscatter diffraction (EBSD methods. On mica, we found, in the absence of Mg2+, the substrates’ (001 surfaces with hexagonal and pseudo-hexagonal two-dimensional (2-D structure can affect the orientation of calcite nucleation with calcite (001 ~// mica (001 and calcite (010 ~// mica (010 to be the major interfacial relationship. On hematite, we did not observe frequent twinning relationship between adjacent calcite gains, but often saw preferentially nucleation of calcite at surface steps on hematite substrate. We suggest that calcite crystals initially nucleate from the Ca2+ layers adsorbed on the surfaces. The pseudo-hexagonal symmetry on mica (001 surface also leads to the observed calcite (001 twinning. A second and less common orientation between calcite {104} and mica (001 was detected but could be due to local structure damage of the mica surface. Results in the presence of Mg2+ show that the substrate surfaces can weaken Mg toxicity to calcite nucleation and lead to a higher level of Mg incorporation into calcite lattice.

Filogenómica y genómica de la adaptación

OpenAIRE

Zardoya, Rafael; Sánchez-Gracia, Alejandro; Rozas Liras, Julio A.

2017-01-01

La posibilidad técnica actual de secuenciar genomas y transcriptomas completos de cualquier especie abre la puerta a cumplir la predicción de Darwin de poder reconstruir de forma rigurosa el árbol de la vida (las relaciones filogenéticas de todos los seres vivos actuales) mediante la filogenómica.

Relaciones económicas bilaterales entre Ecuador y Brasil

OpenAIRE

Herrera Díaz, Stefany Natalie

2015-01-01

Dentro de la dinámica mundial actual, resulta de especial interés para Ecuador el análisis de sus relaciones económicas bilaterales con Brasil, debido al papel protagónico que ha alcanzado este país tanto a nivel regional como mundial. A nivel regional, varios de los países vecinos han delineado, incluso, su política exterior en función de potenciar sus relaciones políticas y económicas con él, y a nivel internacional, su participación en la geopolítica mundial es cada vez mayor. En términos ...

La argumentación en la formación de profesores de química: relaciones con la comprensión de la historia de la química

Directory of Open Access Journals (Sweden)

Pablo Antonio Archila

2014-01-01

Full Text Available En este artículo se trata el tema de la argumentación en ciencias de la naturaleza como habilidad de pensamiento y se promueve su inclusión en la formación inicial de profesores de química, pues se reconocen sus potencialidades para la mejora de las comprensiones que los futuros profesores podrían construir acerca de la historia de la química. Para tal fin, se aborda una breve revisión histórica de uno de los hitos de la química, como lo es el desarrollo de la química estructural, con lo cual se sugiere una de las actividades que forman parte de un módulo propuesto para la preparación en argumentación de profesores de química. Finalmente, se discuten algunas reflexiones y perspectivas que resultarían de la articulación entre argumentación e historia de la química.

Dinámica ambiental y económica en la localidad de Puente Aranda en Bogotá

Directory of Open Access Journals (Sweden)

Carlos Fernando Parra Moreno

2014-01-01

Full Text Available Este documento muestra los resultados parciales de la investigación “Responsabilidad social y ambiental de la industria manufacturera en la localidad de Puente Aranda en la ciudad de Bogotá como alternativa al desarrollo humano integral sustentable”, realizados dentro del marco de trabajo del grupo de investigación Girsa. El estudio se basó en el análisis de la dinámica poblacional, ambiental y económica de la dicha localidad, a través de la metodología de la matriz de Vester. Con este instrumento se logró identificar las relaciones e interacciones dinámicas de todos los actores locales en el tiempo y en el espacio. Dentro de los problemas críticos que se encontraron en la localidad de Puente Aranda se encontró el agotamiento de fuentes hídricas, poca conciencia y educación ambiental de la población, una mala disposición de basuras, la no disponibilidad de servicios públicos para los nuevos asentamientos y altos niveles de emisión de partículas contaminantes.

Temas de Física para Ingeniería: Primer principio de la termodinámica

OpenAIRE

Beléndez Vázquez, Augusto

1992-01-01

Acústica, fluidos y termodinámica: "Primer principio de la termodinámica". Objetivos y caracteres generales de la termodinámica. Conceptos fundamentales de la termodinámica. Capacidad calorífica, calor específico y calor latente. Trabajo. Primer principio de la termodinámica: energía interna. Algunas aplicaciones del primer principio.

MICA diversity and linkage disequilibrium with HLA-B alleles in renal-transplant candidates in southern Brazil.

Science.gov (United States)

Yamakawa, Roger Haruki; Saito, Patrícia Keiko; Gelmini, Geórgia Fernanda; da Silva, José Samuel; Bicalho, Maria da Graça; Borelli, Sueli Donizete

2017-01-01

The major histocompatibility complex (MHC) class I chain-related gene A (MICA) is located centromerically to the human leukocyte antigen (HLA)-B. The short distance between these loci in the MHC indicates the presence of linkage disequilibrium (LD). Similarly to the HLA, the MICA is highly polymorphic, and this polymorphism has not been well documented in different populations. In this study, we estimated the allelic frequencies of MICA and the linkage disequilibrium with HLA-B alleles in 346 renal-transplant candidates in southern Brazil. MICA and HLA were typed using the polymerase chain reaction-sequence-specific primer method (PCR-SSO), combined with the Luminex technology. A total of 19 MICA allele groups were identified. The most frequent allele groups were MICA*008 (21.6%), MICA*002 (17.0%) and MICA*004 (14.8%). The most common haplotypes were MICA*009-B*51 (7.8%), MICA*004-B*44 (6.06%) and MICA*002-B*35 (5.63%). As expected from the proximity of the MICA and HLA-B loci, most haplotypes showed strong LD. Renal patients and healthy subjects in the same region of Brazil showed statistically significant differences in their MICA polymorphisms. The MICA*027 allele group was more frequent in renal patients (Pc = 0.018, OR: 3.421, 95% CI: 1.516-7.722), while the MICA*019 allele group was more frequent in healthy subjects (Pc = 0.001, OR: 0.027, 95% CI: 0.002-0.469). This study provided information on the distribution of MICA polymorphisms and linkage disequilibrium with HLA-B alleles in Brazilian renal-transplant candidates. This information should help to determine the mechanisms of susceptibility to different diseases in patients with chronic kidney disease, and to elucidate the mechanisms involved in allograft rejection associated with MICA polymorphisms in a Brazilian population.

Using X-ray photoelectron spectroscopy to discriminate among different sorption sites of micas: With implications for heterogeneous reduction of chromate at the mica-water interface

Energy Technology Data Exchange (ETDEWEB)

Ilton, E.S.; Moses, C.O.; Veblen, D.R.

2000-04-01

This contribution uses Cr2p and 3p binding energies (BEs) determined by X-ray photoelectron spectroscopy (XPS) to distinguish Cr{sup III} sorbed to different mica sorption sites. The results were used to better understand mechanisms for coupled sorption-reduction of Cr{sub (aq)}{sup VI} by ferrous micas. The research is important because: (1) Cr contamination is a serious and wide spread problem associated with a variety of industries; (2) Micas are important sorbents for Cr because they are ubiquitous, sorb cations and anions over a wide range of pH, and participate in heterogeneous redox reactions via structural Fe{sup II} and FE{sup III}; and (3) The mobility of cations sorbed by micas will depend, in part, on the dominant sorption site. Micas (two biotites, end member phologopite and muscovite) were reacted with Cr{sup III} solutions that contained variable concentrations of NaCl and KCl. Samples were extracted at times intervals and mica edge orientations were analyzed by ZPS. Cr{sub (aq)}{sup III} sorption was greater in Cr{sup III}-NaCl solutions relative to Cr{sup III}-KCl solutions. Cr2p and 3p BEs were bracketed by those for Cr{sup III} in the structure of silicates and in Cr{sup III}-oxyhydroxides. The BE of Cr{sup III} sorbed to micas was higher by about 0.3 eV after reaction with Cr{sup III}-NaCl solutions compared to Cr{sup III}-KCl aqueous solutions. At the experimental conditions, Na{sup +} and K{sup +} differentially block permanent charge sites but not variably charged edge sites of micas. Using the constraints inherent in the experimental design, the authors interpret the difference in CR{sup III} BE between the Cr{sup III}-NaCl and Cr{sup III}-KCl experiments to reflect a change in the dominant sorption site, where high and low Cr BEs indicate Cr sorbed by the interlamellar region and variably charged functional groups at mica edges, respectively. They conclude that small BE shifts for cations sorbed to silicates can be interpreted with

Alfabetización económica y actitudes hacia la compra en universitarios posterior a un programa de educación económica

Directory of Open Access Journals (Sweden)

Marianela Denegri Coria

2016-01-01

después de participar en el programa de Educación Económica se les aplicó la Escala de Actitudes hacia la Compra y el Consumo y el Test de Alfabetización Económica para adultos (TAE-A. Los resultados indican una menor tendencia hacia la impulsividad en la compra y el consumo en los estudiantes después de participar en la intervención. Las implicancias de este estudio enfatizan la necesidad de crear tempranamente programas de formación económica para favorecer el cambio actitudinal y el consumo reflexivo.

Experiencias divertidas de electroquímica casera

OpenAIRE

Santiago Heredia-Avalos

2007-01-01

La química, dentro de la cual se incluye la electroquímica, es una materia que los estudiantes suelen ver como complicada, aburrida, carente de interés y que, además requiere de material de laboratorio sofisticado y reactivos químicos inaccesibles. Nada más lejos de la realidad, tal y como se pondrá de manifiesto en este trabajo, donde se proponen varias experiencias sencillas usando sustancias baratas, la mayoría de las cuales pueden encontrarse en un supermercado, y utensilio...

Scrophulariaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Scrophulariaceae es reconocida en el Perú por presentar alrededor de 18 géneros y 35 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, principalmente herbáceas. En este trabajo reconocemos dos especies endémicas en dos géneros, las cuales se encuentran principalmente en la región Bosques Húmedos Amazónicos, entre los 200 y 1000 m de altitud. Ninguna de las especies endémicas se encuentra representada dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Oleaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Isidoro Sánchez

2013-10-01

Full Text Available La familia Oleaceae es reconocida en el Perú por presentar seis géneros y 13 especies (Brako & Zarucchi, 1993, la mayoría árboles. En este trabajo reconocemos dos especies endémicas en igual número de géneros. Las especies endémicas han sido encontradas en las regiones Matorral Desértico y Bosques Húmedos Amazónicos, entre los 250 y 1850 m de altitud. Ambas especies se encuentran dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

El Área de Ciencia y Tecnologías Químicas del CSIC: ¿Un Área de químicas?

Directory of Open Access Journals (Sweden)

García-López, María Teresa

2002-08-01

Full Text Available Not available

El artículo titulado "El Area de Ciencia y Tecnologías Químicas del CSIC: ¿un Area de químicas?» pretende mostrar una breve panorámica del lugar que ocupa el género femenino dentro de la citada Area. En la primera parte se aportan las estadísticas que reflejan el número y porcentaje de científicas totales en los distintos Institutos del Area, así como su distribución entre las tres escalas de personal científico del Organismo. Una segunda parte está dedicada a recoger las aportaciones personales de varias científicas del Area acerca del tema, visto desde sus propias experiencias.

Dinámicas de la actividad científica del Instituto de Investigaciones Socio-Económicas de la Universidad Nacional de San Juan de Argentina

Directory of Open Access Journals (Sweden)

Gonzalo Miguel Castillo

2018-02-01

Full Text Available Este artículo fue un estudio de caso en torno a las capacidades de investigación generadas en el Instituto de Investigaciones Socio-Económicas de la Facultad de Ciencias Sociales, perteneciente a la Universidad Nacional de San Juan, en Argentina. Aborda los principales acontecimientos históricos de la institución y su dinámica actual, tuvo en cuenta las áreas de conocimiento en las cuales se desarrollan sus investigaciones. A su vez, este trabajo ha descrito las dinámicas de la revista académica producida en este instituto, denominada REVIISE. La metodología fue un abordaje objetivo/descriptivo. Se procedió a analizar el papel, devenir y accionar del IISE y las modalidades de proyectos de investigación ejecutados. Fueron indagados el funcionamiento de la REVIISE, identificando perfiles académicos de sus autores, circuitos de difusión y redes académicas; y la conformación de comités y consejos editoriales y académicos que componen esta publicación. Se propone realizar un recorrido que atraviesa lo institucional, los agentes académicos y la principal red de difusión de la producción de conocimiento para comprender las capacidades investigativas del Instituto de Investigaciones Socio Económicas.

Observation of {ital B}{sup +}{r_arrow}{ital {omega}K}{sup +} and Search for Related {ital B} Decays Modes

Energy Technology Data Exchange (ETDEWEB)

Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D.; Hans, R.M.; Johnson, E.; Karliner, I.; Marsh, M.A.; Palmer, M.; Selen, M.; Thaler, J.J. [University of Illinois, Urbana-Champaign, Illinois 61801 (United States); Edwards, K.W.; Edwards, K.W. [Institute of Particle Physics (Canada); Bellerive, A.; Bellerive, A.; Janicek, R.; Janicek, R.; MacFarlane, D.B.; MacFarlane, D.B.; Patel, P.M.; Patel, P.M. [Institute of Particle Physics (Canada); Sadoff, A.J. [Ithaca College, Ithaca, New York 14850 (United States); Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Darling, C.; Davis, R.; Kotov, S.; Kravchenko, I.; Kwak, N.; Zhou, L. [University of Kansas, Lawrence, Kansas 66045 (United States); Anderson, S.; Kubota, Y.; Lee, S.J.; ONeill, J.J.; Poling, R.; Riehle, T.; Smith, A. [University of Minnesota, Minneapolis, Minnesota 55455 (United States); Alam, M.S.; Athar, S.B.; Ling, Z.; Mahmood, A.H.; Timm, S.; Wappler, F. [State University of New York at Albany, Albany, New York 12222 (United States); Anastassov, A.; Duboscq, J.E.; Fujino, D.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Severini, H.; Skubic, P. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; Yurko, M. [Purdue University, West Lafayette, Indiana 47907 (United States); Glenn, S.; Kwon, Y.; Lyon, A.L.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Savinov, V.; Ugolini, D.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Shelkov, V.; Staeck, J.; and others

1998-07-01

We have searched for two-body charmless decays of B mesons to purely hadronic exclusive final states including {omega} or {phi} mesons using data collected with the CLEO II detector. With this sample of 6.6{times}10{sup 6} B mesons we observe a signal for the {omega}K{sup +} final state, and measure a branching fraction of B(B{sup +}{r_arrow}{omega}K{sup +}) =(1.5{sup +0.7}{sub {minus}0.6}{plus_minus}0.2){times} 10{sup {minus}5} . We also observe some evidence for the {phi}K{sup {asterisk}} final state, and upper limits are given for 22 other decay modes. These results provide the opportunity for studies of theoretical models and physical parameters. {copyright} {ital 1998} {ital The American Physical Society}

Morphology and thermal degradation study of poly(lactic acid)/synthetic mica composites

International Nuclear Information System (INIS)

Souza, D.H.S.; Dias, M.L.

2010-01-01

Poly(lactic acid) (PLA)/synthetic mica composites has been little studied in the literature. In this work, an organophilic synthetic mica was used to prepare PLA nanocomposites. The composites were obtained at an internal mixer containing 3, 5, 7 and 10 wt% of mica. The materials were analyzed by x-ray diffraction, thermogravimetric analysis and gel permeation chromatography. (author)

Mössbauer spectra of white micas from the Central Western Carpathians Mountains

Science.gov (United States)

Sitek, J.; Sulák, M.; Putiš, M.; Tóth, I.

2010-03-01

Potassium white micas from the rocks included into Cretaceous deformation zones (ca. 100-70 Ma in age) of the Central Western Carpathians were investigated by Mössbauer spectroscopy. White micas formed during a polystage evolution and changing P-T conditions of their crystallization in crustal-scale shear zones. We found criteria for distinguishing generations of celadonite-poor (muscovitic) and celadonite-rich (phengitic) white micas using Mössbauer spectroscopy. This method revealed contrasting spectra characterized by typical quadrupole doublets corresponding to Fe2+ Fe3+ contents in white micas. They are in the range of 2.9-3.0 mm/s for phengite, and 2.6-2.7 mm/s for muscovite. Mössbauer spectra reflect well the chemical changes in white mica aggregates, especially of those close to the end-member muscovite and (alumino-)celadonite compositions.

ARGX-87: Accident Response Group Exercise, 1987: A Broken Arrow mini exercise

International Nuclear Information System (INIS)

Schuld, E.P.; Cruff, D.F.

1987-07-01

A Broken Arrow mini exercise dubbed ''Accident Response Group Exercise - 1987'' (ARGX-87) was conducted on June 1, 1987 at the Lawrence Livermore National Laboratory (LLNL) and Sandia National Laboratories, Livermore (SNLL). The exercise started at 0445 PDT with a call from the Department of Energy (DOE) - EOC in Washington, DC, to the Albuquerque Operations (AL - ) - EOC. AL, in turn, called the Laboratory off-hour emergency number (Fire Dispatcher), who called the Laboratory Emergency Duty Officer (LEDO). The LEDO then contacted the Accident Response Group (ARG) Senior Scientific Advisor. Calls were placed to assemble appropriate members of the ARG in the ALERT Center. No phone number for SNLL was available at the Albuquerque Operations EOC, so a controller injected a message to SNLL to get them involved in the exercise. The messages received at the Laboratory identified the Air Force line item weapon system involved in the accident and the accident location. As people arrived at the ALERT Center they began discussing the details of the accident. They also started working the deployment logistics and other issues. Travel arrangements for the HOT SPOT equipment and ARG personnel were made for immediate deployment to the accident site in North Dakota. The exercise was terminated at 0840 as planned. While certain procedural deficiencies were noted, the exercise was considered a valuable learning experience. The results and observations from this experience will be used to refine the operating procedures and the training program

Clinical relevance of pre and post-transplant immune markers in kidney allograft recipients: anti-HLA and MICA antibodies and serum levels of sCD30 and sMICA.

Science.gov (United States)

Solgi, Ghasem; Furst, Daniel; Mytilineos, Joannis; Pourmand, Gholamreza; Amirzargar, Ali Akbar

2012-03-01

This retrospective study aims to determine the prognostic values of HLA and MICA antibodies, serum levels of sCD30 and soluble form of MHC class I related chain A (sMICA) in kidney allograft recipients. Sera samples of 40 living unrelated donor kidney recipients were tested by ELISA and Flow beads techniques for the presence of anti HLA and MICA antibodies and the contents of sCD30 and sMICA. HLA and MICA antibody specification was performed by LABScreen single antigen beads to determine whether the antibodies were directed against donor mismatches. Within first year post operatively 9 of 40 patients (22.5%) showed acute rejection episodes (ARE) that four of them lost their grafts compared to 31 functioning transplants (P=0.001). The presence of HLA antibodies before and after transplantation was significantly associated with ARE (P=0.01 and P=0.02 respectively). Sensitization to HLA class II antigens pre-transplant was strongly associated with higher incidence of ARE (P=0.004). A significant correlation was found between ARE and appearance of non-donor specific antibodies (P=0.02). HLA antibody positive patients either before or after transplantation showed lower graft survival rates than those without antibodies during three years follow-up (P=0.04 and P=0.02). Anti-MICA antibodies were observed in 8/40(20%) and 5/40(12.5%) of patients pre and post-transplant respectively. Coexistence of HLA and MICA antibodies was shown in 2 of 4 cases with graft loss. A significant increased level of sCD30 at day 14 (P=0.001) and insignificant decreased levels of sMICA pre and post operatively were detected in rejecting transplants compared to functioning graft group. Our findings support the view that monitoring of HLA and MICA antibodies as well as sCD30 levels early after transplant has predictive value for early and late allograft dysfunctions and the presence of these factors are detrimental to graft function and survival. Copyright © 2012 Elsevier B.V. All rights

AVALIAÇÃO FÍSICA, QUÍMICA, BIOQUÍMICA E AGRONÔMICA DE CULTIVARES DE FEIJÃO-GUANDU (CAJANUS CAJAN (L MILL

Directory of Open Access Journals (Sweden)

SOLANGE GUIDOLIM CANNIATTI-BRAZACA

2009-07-01

Full Text Available

RESUMO: Foram estudadas as características físicas, químicas, bioquímicas e agronômicas de 40 cultivares de feijão-guandu (Cajanus cajan (L Mill provenientes da EMBRAPA de São Carlos (SP e originárias de diversas regiões do Brasil e da Índia. Pode-se observar entre os cultivares variações expressivas no tempo de cocção, no teor de lectinas e na produtividade. Os resultados obtidos quanto ao teor protéico e à digestibilidade do guandu, quando comparadas com os resultados obtidos na literatura, mostraram-se semelhantes aos dos grãos de feijão-comum. Pode-se, também, observar baixos teores de taninos entre os cultivares estudados. Foram selecionados três cultivares por apresentarem melhores características entre os parâmetros estudados. PALAVRAS-CHAVE: Feijão-guandu; proteínas; fatores antinutricionais; produtividade.

O uso de técnica eletroquímica para a descontaminação de estruturas cerâmicas vítreas porosas

OpenAIRE

Assis,O. B. G.; Silva,E. R.

2010-01-01

Apresentamos neste trabalho os resultados de ensaios preliminares para avaliar o uso de técnica de eletro-osmose para a remoção de contaminantes orgânicos em estruturas porosas cerâmicas, como filtros ou similares. A técnica consiste em forçar a migração de contaminantes retidos na estrutura interna ou na superfície dos poros por meio da aplicação de tensão controlada em célula eletroquímica projetada para este fim. As moléculas absorvidas na superfície cerâmica estarão sujeitas as ações cisa...

Actitudes y rendimiento académico: su evolución desde química general e inorgánica hasta química orgánica

Directory of Open Access Journals (Sweden)

María S. Reyes

2014-01-01

Full Text Available Esta investigación tiene un doble propósito, en primer lugar, valorar las actitudes hacia la química de alumnos universitarios de carreras biológicas en dos cursos relacionados con esta disciplina y, por otro lado, relacionar dichas actitudes con el rendimiento académico presentado por los estudiantes. El instrumento elegido para medir las actitudes de los alumnos fue un cuestionario según la escala Likert, encuestándose a la totalidad de estudiantes que cursaban cada uno de los cursos de química analizados: Química General e Inorgánica (QGI y Química Orgánica (QO. Para estimar el rendimiento académico se analizaron actas de parciales y se realizaron cálculos de correlación. Los alumnos que cursaban QGI presentaron actitudes hacia la química valoradas como indiferentes. Sin embargo al finalizar el curso de QO sus actitudes fueron evolucionando favorablemente, ya que la puntuación media obtenida para los ítems positivos y negativos estuvo en el rango de actitudes positivas. Los valores del coeficiente de Pearson obtenidos para los dos cursos estudiados fueron superiores a 0,80, lo que indica una fuerte relación entre las variables implicadas, por lo cual se infiere la importancia de desarrollar actitudes positivas hacia la química para favorecer el rendimiento académico de los alumnos.

Transparent Indium Tin Oxide Electrodes on Muscovite Mica for High-Temperature-Processed Flexible Optoelectronic Devices.

Science.gov (United States)

Ke, Shanming; Chen, Chang; Fu, Nianqing; Zhou, Hua; Ye, Mao; Lin, Peng; Yuan, Wenxiang; Zeng, Xierong; Chen, Lang; Huang, Haitao

2016-10-26

Sn-doped In 2 O 3 (ITO) electrodes were deposited on transparent and flexible muscovite mica. The use of mica substrate makes a high-temperature annealing process (up to 500 °C) possible. ITO/mica retains its low electric resistivity even after continuous bending of 1000 times on account of the unique layered structure of mica. When used as a transparent flexible heater, ITO/mica shows an extremely fast ramping (solar cells (PSCs) with high efficiency.

Dinamizando el proceso de enseñanzaaprendizaje de la química. Las demostraciones químicas como una opción para cambiar la forma tradicional de enseñar química

Directory of Open Access Journals (Sweden)

Manuel Molina Caballero

2009-10-01

Full Text Available Creemos que la “quimifobia” que existe a nivel social está generada en buena medida por la forma cómo se realiza la enseñanza de la química en las aulas. Para generar un cambio en las metodologías habituales proponemos, en este trabajo, el uso de las demostraciones químicas, mostrando un ejemplo a partir de la descomposición del peróxido de hidrógeno, buscando la forma de incorporar las demostraciones en el aula y considerando su carácter atractivo, la participación del estudiante, su vínculo conceptual y las cuestiones de seguridad a tener en cuenta. Dejamos a los profesores la propuesta, esperando que con su ayuda quizá podamos dar un toque especial a la enseñanza de la química.

La imagen pública de la química y su relación con la generación de actitudes hacia la química y su aprendizaje

Directory of Open Access Journals (Sweden)

William Manuel Mora Penagos

2012-04-01

Full Text Available El presente ensayo muestra cómo la imagen popular y escolar de la química se caracteriza por ser negativa, lo que viene incidiendo en la generación de actitudes negativas hacia esta ciencia y su aprendizaje. Las inadecuadas formas de comunicación del conocimiento de la química que se muestran en el cine, la TV y las revistas de ciencia popular, la visión irreconciliable entre ciencia y religión, y la poca claridad de las formas de producción del conocimiento químico mostradas en las aulas de clase, aparecen como las principales causas de esta situación. Superar esta imagen implica reconciliar la visión científica con la visión social de la química, por lo que el conocimiento en epistemología e historia de la química y la línea de investigación conocida como Public Understanding of Science desde el enfoque Ciencia/Tecnología/ Sociedad y Ambiente (CTS-A, son fundamentales para una didáctica de la química orientada hacia la alfabetización en química y a la formación docentes en torno al diseño curricular y la enseñanza de contenidos articulados a la generación de actitudes hacia el impacto social y ambiental de la química.

Cuscutaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Cuscutaceae es reconocida en el Perú por presentar un género, Cuscuta, y 19 especies (Brako & Zarucchi, 1993, todas ellas hierbas. En este trabajo reconocemos siete especies endémicas, aunque en necesidad de revisión taxonómica y colecciones botánicas; por ello no se aplicaron las categorías y criterios de la UICN. Estos taxones endémicos ocupan principalmente la región Mesoandina, por debajo de los 3200 m de altitud. Aparentemente, sólo una de estas especies se encuentra representada dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Dilleniaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Dilleniaceae es una adición reciente a la flora endémica peruana; los endemismos han sido recolectados y reconocidos hacia fines de los 1990. Está representada en el Perú por seis géneros y 23 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, la mayoría lianas. En este trabajo reconocemos tres endemismos en dos géneros. Las especies endémicas ocupan la región Bosques Húmedos Amazónicos, entre los 100 y 125 m de altitud. No se encuentra representada en el Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Las cooperativas: Una alternativa económica y social frente a la crisis

Directory of Open Access Journals (Sweden)

Javier Divar Garteiz-Aurrecoa

2013-12-01

Full Text Available El Cooperativismo nació como alternativa económica y social, impulsado por la piedad religiosa y reglado bajo los principios democráticos. La solidaridad y la democracia económica hacen de las cooperativas  sociedades especialmente resistentes frente a las dificultades económicas.Recibido: 29.05.2013Aceptado: 26.06.2013

Principios de laboratorio y aplicaciones en la práctica clínica de las técnicas moleculares, genómicas y proteómicas

Directory of Open Access Journals (Sweden)

Jenny Hernández Betancourt

2014-10-01

Full Text Available La heterogénea expresión clínica de las enfermedades, la necesidad de la interpretación de los procesos fisiológicos y fisiopatológicos, así como la búsqueda incesante de nuevas estrategias diagnósticas y terapéuticas, han conducido al desarrollo de las biociencias, en particular de la genética, la genómica, la biología molecular y las tecnologías asociadas. Han emergido en los últimos años disciplinas como la trascriptómica, la epigenómica, la proteómica y la metabolómica, cada una con un objeto de estudio determinado, que deriva de los tipos moleculares específicos y sus relaciones y todas con aplicaciones potenciales dentro de una nueva medicina con un enfoque personalizado. Hoy se dispone de técnicas moleculares que se basan en la hibridación de ácidos nucleicos, tanto in situ como el dot-blot, el Southern blot y el Northern blot. Otros métodos requieren la amplificación del ADN, como la reacción en cadena de la polimerasa, los microarreglos y la secuenciación. La proteómica se perfila como una potente herramienta para el estudio de aspectos fisiológicos y patológicos del ser humano; sus técnicas incluyen la electroforesis bidimensional, la espectrometría de masas y las micromatrices de proteínas. La búsqueda activa de biomarcadores a partir de casi todos los líquidos biológicos y tejidos de varias naturalezas es una de las principales aplicaciones de la proteómica. Es importante atender, comprender e introducir estos nuevos métodos en la práctica clínica por sus potencialidades para el diagnóstico, el desarrollo de estrategias terapéuticas, la predicción y estratificación de riesgo, de la resistencia al tratamiento y las posibilidades de supervivencia

Funciones Económicas en un Entorno Incierto

OpenAIRE

Lazzari, Luisa L; Chiodi, Jorge A; Moulia, Patricia I

2015-01-01

El mundo está atravesando una de las crisis económicas más profundas de los últimos tiempos. Los escenarios actuales y futuros están plagados de incertidumbre que, en general, no se considera en el análisis de las distintas funciones económicas de interés para el desarrollo del negocio, y la realidad se representa mediante modelos estáticos y casi perfectos del comportamiento de los mercados. La teoría de conjuntos borrosos permite construir modelos adecuados a partir de realidades inciertas ...

CD56+ immune cell infiltration and MICA are decreased in breast lobules with fibrocystic changes.

Science.gov (United States)

Kerekes, Daniel; Visscher, Daniel W; Hoskin, Tanya L; Radisky, Derek C; Brahmbhatt, Rushin D; Pena, Alvaro; Frost, Marlene H; Arshad, Muhammad; Stallings-Mann, Melody; Winham, Stacey J; Murphy, Linda; Denison, Lori; Carter, Jodi M; Knutson, Keith L; Degnim, Amy C

2018-02-01

While the role of natural killer (NK) cells in breast cancer therapy has been investigated, little information is known about NK cell function and presence in nonmalignant and premalignant breast tissue. Here, we investigate and quantify NK cell marker CD56 and activating ligand MICA in breast tissue with benign breast disease. Serial tissue sections from 88 subjects, 44 with benign breast disease (BBD) who remained cancer-free, and 44 with BBD who later developed cancer, were stained with H&E, anti-MICA, and anti-CD56. Up to ten representative lobules were identified on each section. Using digital image analysis, MICA and CD56 densities were determined for each lobule, reported as percent of pixels in the lobule that registered as stained by each antibody. Analyses were performed on a per-subject and per-lobule basis. Per-subject multivariate analyses showed associations of CD56 and MICA with age: CD56 was increased in older subjects (p = 0.03), while MICA was increased in younger subjects (p = 0.005). Per-lobule analyses showed that CD56 and MICA levels were both decreased in lobules with fibrocystic change, with median levels of CD56 and MICA staining, respectively, at 0.31 and 7.0% in fibrocystic lobules compared to 0.76 and 12.2% in lobules without fibrocystic change (p fibrocystic lobules, proliferative/atypical lobules showed significantly lower expression compared to nonproliferative lobules for MICA (p = 0.02) but not for CD56 (p = 0.80). Levels of CD56+ NK cells and activating ligand MICA were decreased in breast lobules with fibrocystic change, and MICA levels showed a significant stepwise decrease with increasing histopathologic abnormality. MICA levels were also significantly decreased in older subjects, who generally have higher risk of developing cancer. These findings advance a model in which MICA promotes cytotoxic activity in CD56+ NK cells to protect against tumorigenesis in breast lobules, and suggest further research is warranted.

Influencia de la autoeficacia académica y la procrastinación académica sobre el cansancio emocional de estudiantes de la Universidad Alas Peruanas, Lima, 2015

OpenAIRE

Gutiérrez Torres, Andrés Martín

2015-01-01

Objetivo: determinar cuánta es la influencia de la autoeficacia académica y la procrastinación académica sobre el cansancio emocional de estudiantes de la Universidad Alas Peruanas, Lima, 2015. Metodología: se usó un diseño observacional, transversal, retrospectivo y correlacional-causal. La muestra no probabilística fue de 332 estudiantes de Psicología de una universidad privada de Lima, quienes fueron evaluados con tres instrumentos: Escala de Autoeficacia para Situaciones Académicas, E...

Loranthaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Loranthaceae está representada en la flora peruana por 11 géneros y 63 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, la mayoría arbustos. En este trabajo se reconoce 14 especies endémicas en cinco géneros. Los endemismos en esta familia ocupan diversas regiones, como la Mesoandina, Puna Húmeda y Seca y Bosques Muy Húmedos Montanos, desde los 1400 hasta los 4200 m de altitud. Se aplicaron las categorías y criterios de la UICN a 11 especies. Cinco especies endémicas se encuentran representadas en del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Crassulaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Crassulaceae es reconocida en el Perú por presentar cinco géneros y 29 especies (Brako & Zarucchi, 1993, mayormente arbustos y hierbas. En este trabajo reconocemos 13 especies y dos variedades como endemismos peruanos en tres géneros. Echeveria es el género con el mayor número de especies endémicas. Los taxones endémicos ocupan principalmente las regiones Mesoandina y Puna Húmeda y Seca, entre los 1700 y 4500 m de altitud. Se aplicaron las categorías y criterios de la UICN a nueve taxones. Dos Crassulaceae endémicas están representados dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Optimal PMU location in power systems using MICA

Directory of Open Access Journals (Sweden)

Seyed Abbas Taher

2016-03-01

Full Text Available This study presented a modified imperialist competitive algorithm (MICA for optimal placement of phasor measurement units (PMUs in normal and contingency conditions of power systems. The optimal PMU placement problem is used for full network observability with the minimum number of PMUs. For this purpose, PMUs are installed in strategic buses. Efficiency of the proposed method is shown by the simulation results of IEEE 14, 30, 57, and 118-bus test systems. Results of the numerical simulation on IEEE-test systems indicated that the proposed technique provided maximum redundancy measurement and minimum request of PMUs so that the whole system could be topologically observable by installing PMUs on the minimum system buses. To verify the proposed method, the results are compared with those of some recently reported methods. When MICA is used for solving optimal PMU placement (OPP, the number of PMUs would be usually equal to or less than those of the other existing methods. Results indicated that MICA is a very fast and accurate algorithm for OPP solution.

Computadores y democracia económica

Directory of Open Access Journals (Sweden)

Allin Cottrell

2008-12-01

Full Text Available El colapso del socialismo anteriormente existente obedeció a causas integradas en su mecanismo económico, que no son inherentes a todos los socialismos posibles. El artículo muestra que la teoría económica marxista, junto con la informática, proporciona el fundamento para adelantar un programa económico socialista viable y que el desarrollo de la informática y de Internet hace posible la planificación económica. Además, argumenta que el movimiento socialista nunca desarrolló un programa constitucional correcto y que la tecnología moderna abre nuevas oportunidades para la democracia. Por último, revisa los argumentos austriacos contra la posibilidad del cálculo socialista a la luz de la nueva capacidad informática y de las limitaciones del Protocolo de Kyoto.

Farmacogenómica

OpenAIRE

Izaguirre Pasquel, Victor

2014-01-01

La farmacogenómica, área de investigación innovadora y de reciente desarrollo, surge para explicar las diferencias interindividuales en la respuesta a los fármacos y evitar reacciones adversas y costes innecesarios. Básicamente, esta nueva ciencia tiene dos orientaciones, una centrada en el diseño de fármacos para el tratamiento de una enfermedad que tiene un marcado carácter genético y otra, en el diseño de fármacos con menor toxicidad para pacientes con deficiencias y/o alteraciones génicas...

The role of herbometallic preparations in traditional medicine--a review on mica drug processing and pharmaceutical applications.

Science.gov (United States)

Wijenayake, Apsara; Pitawala, Amarasooriya; Bandara, Ratnayake; Abayasekara, Charmalie

2014-09-11

Biotite mica enriched with Fe(2+) ions are widely used as a major mineral ingredient in traditional pharmaceutical science of alchemy (Rasashastra). Abhrak bhasma (mica ash), a pharmaceutical product containing treated mica, is utilized, for example, in Ayurvedic treatments for ailments such as gastritis, renal disease, skin disease and mainly in rejuvenation formulations. However, the untreated mica minerals may be harmful when used directly, as they carry considerably high amounts of trace-elements that can cause undesirable effects in the human body. In order to remove toxic factors and produce readily absorbable materials having high nutrient capacity, specific thermal and chemical treatments (purification, detoxification, particle size reduction and incineration) are performed during the preparation of Rasashastra. This review evaluates the chemical and pharmacological aspects of mica ash as well as the technological aspects of mica ash production. The detailed literature review on the chemistry and scientific basis of mica ash, its preparation techniques, mica alterations and pharmaceutical applications was carried out by using published Ayurvedic text books and research articles, available from Science Direct, on mica minerals, mica ash and their physico-chemical alteration processes and pharmacological applications. During the purification and detoxification procedures, heating followed by quenching (in ionic medium) influences the structural distortion and the development of stress-induced cracks and spallations of the micaceous plates. Thus, the efficient diffusion of the external medium takes place at successive heating and quenching steps. Acidic organic liquids and animal byproducts can enhance the cation exchange capacity and solubility of mica. Further, these natural compounds facilitate the removal of toxic-elements in the structure. When treated-mica and paddy husks are tied up in a cloth and squeezed, particle size reduction and further

Molecular dynamics study of room temperature ionic liquids with water at mica surface

Directory of Open Access Journals (Sweden)

Huanhuan Zhang

2018-04-01

Full Text Available Water in room temperature ionic liquids (RTILs could impose significant effects on their interfacial properties at a charged surface. Although the interfaces between RTILs and mica surfaces exhibit rich microstructure, the influence of water content on such interfaces is little understood, in particular, considering the fact that RTILs are always associated with water due to their hygroscopicity. In this work, we studied how different types of RTILs and different amounts of water molecules affect the RTIL-mica interfaces, especially the water distribution at mica surfaces, using molecular dynamics (MD simulation. MD results showed that (1 there is more water and a thicker water layer adsorbed on the mica surface as the water content increases, and correspondingly the average location of K+ ions is farther from mica surface; (2 more water accumulated at the interface with the hydrophobic [Emim][TFSI] than in case of the hydrophilic [Emim][BF4] due to the respective RTIL hydrophobicity and ion size. A similar trend was also observed in the hydrogen bonds formed between water molecules. Moreover, the 2D number density map of adsorbed water revealed that the high-density areas of water seem to be related to K+ ions and silicon/aluminum atoms on mica surface. These results are of great importance to understand the effects of hydrophobicity/hydrophicility of RTIL and water on the interfacial microstructure at electrified surfaces. Keywords: Room temperature ionic liquids, Hydrophobicity/hydrophicility, Water content, Electrical double layer, Mica surface

MeV fullerene impacts on mica

Energy Technology Data Exchange (ETDEWEB)

Doebeli, M.; Scandella, L. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Ames, F. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

1997-09-01

Hillock heights on mica irradiated with MeV C{sub 60} ions have been investigated systematically. Results show that the small range of secondary particles along the track plays a crucial role in defect production. (author) figs., tab., refs.

Road work zone accident studies : Advanced Research On Road Work Zone Safety Standard in Europe ARROWS Task 2.2 internal report. On behalf of the European Union, Directorate-General for Transport DG VII-E3, Transport RTD Programme.

NARCIS (Netherlands)

Gundy, C.M.

1998-01-01

The primary objective of this study, part of the ARROWS (Advanced Research on Road Work Zone Safety Standards in Europe) project, is to draw conclusions about the nature and extent of work zone traffic accidents. To that end, existing empirical studies concerning work zone traffic accidents have

La elite económica Argentina, 1810-1914

Directory of Open Access Journals (Sweden)

Roy Hora

2014-12-01

Full Text Available Este artículo analiza los principales rasgos del sector más poderoso de la elite económica argentina del período 1810-1914. El trabajo discute las principales interpretaciones sobre las características y naturaleza de este grupo, pone de relieve algunas de limitaciones de los enfoques más habituales sobre el tema, y sugiere de qué manera conceptualizarlo de forma productiva. Aunque el objeto de este trabajo es la elite económica, todo análisis de este actor supone a la vez una manera de concebir las características del sistema de poder y del entorno económico en el que se desenvuelve la acción de los hombres de fortuna. Por este motivo, este trabajo formula algunas consideraciones generales sobre las características del Estado (argentino y el capitalismo (pampeano, con el fin de precisar mejor qué tipo de elite económica dominó la producción rural y la economía argentina en el período de crecimiento exportador que se extendió desde la Independencia hasta la Primera Guerra Mundial. El trabajo toma distancia de los estudios que enfatizan la importancia de la dimensión política para explicar el proceso de constitución y reproducción de esta elite económica, enfatizando en cambio los determinantes económicos de este proceso. El ensayo no aporta nueva evidencia empírica, sino una reflexión a partir de la literatura existente.

The nanostructure formation on muscovite mica surface induced by intermediate-energy ions

Energy Technology Data Exchange (ETDEWEB)

Zhou, P.; Zhang, HQ., E-mail: zhanghq@lzu.edu.cn; Zhang, Q.; Liu, Z.; Guan, S.; Wang, G.; Zhou, C.; Jia, J.; Lv, X.; Shao, J.; Cui, Y.; Chen, L.; Chen, X., E-mail: chenxm@lzu.edu.cn

2013-07-15

Muscovite mica sheets were bombarded by lithium, carbon and oxygen ions in the energy range from several hundred keV to several MeV. The induced surface structures were measured in the air with atomic force microscopy (AFM) in the tapping mode. The hillock-like structure on the mica surface was observed. The height of the hillock increases linearly when the energy loss is above 1.2 keV/nm. The induced structures are similar with the similar electronic stopping powers but different projectiles for muscovite mica.

El Derecho de Competencia Económica en la Constitución del Ecuador

Directory of Open Access Journals (Sweden)

Marcelo Marín Sevilla

2011-12-01

Full Text Available Este trabajo permite establecer las bases de la Constitución Económica y del Derecho de Competencia Constitucionalizado.  También analiza si las normas de Derecho de la Competencia Económica y su doctrina están acorde y son adecuadas frente a la Constitución del Ecuador. El Derecho de la Competencia Económica tiene normas para investigar y sancionar las Prácticas colusorias; los Abusos de posición de dominio; las normas  para el control de concentraciones económicas; las conductas de Abuso de dependencia económica, y las conductas  de competencia desleal.  Siempre la Autoridad de Competencia analizará estas conductas en función del bienestar del mercado y del consumidor.

A QUÍMICA NA ODONTOLOGIA: CONTRIBUIÇÕES PARA O ENSINO

OpenAIRE

Greyce Arrúa Storgatto

2016-01-01

Esta pesquisa considera a temática Química na Odontologia como ponto de partida para a contextualização de conteúdos químicos, a fim de contribuir para o processo de ensino e aprendizagem de conteúdos de Química para estudantes de 3 série do Ensino Médio de uma escola estadual da cidade de Santa Maria, RS. Ao tratar da Química envolvida em materiais comuns na prática odontológica, bem como ao abordar problemas comuns de saúde bucal e aspectos de sua prevenção e tratamento, a Qu...

Una solución dinámica para juegos con utilidades transferibles

Directory of Open Access Journals (Sweden)

Juan Carlos Cesco

2008-01-01

Full Text Available En este trabajo definimos un tipo de solución dinámica para juegos con utilidades transferibles. La solución dinámica fue introducida por Shenoy (1980 en el marco de juegos abstractos como un medio para describir algunos procesos de negociación. En el contexto de los juegos con utilidades transferibles estudiamos su comportamiento tanto en la clase de los juegos equilibrados (con Core no vacío como en el de los juegos no equilibrados. En esta última subclase mostramos que la solución dinámica debe contener los elementos de ciertos ciclos de preimputaciones denominados ciclos maximales. Estos ciclos aparecen en relación con un esquema dinámico elaborado originalmente para aproximar puntos en el Core de un juego. En la subclase de los juegos equilibrados, la solución dinámica coincide con el Core, lo que establece un enfoque unificado de solución. El problema de existencia de ciclos maximales no está completamente resuelto, pero en algunas subclases de juegos podemos exhibir teoremas de existencia y una descripción completa de la solución dinámica.

EL PAPEL DE LA QUÍMICA ANALÍTICA EN LAS CIENCIAS AMBIENTALES

Directory of Open Access Journals (Sweden)

María A. Dosal

2014-01-01

Full Text Available En este trabajo se presenta una propuesta para abordar la didáctica de la Química Analítica con enfoque de Química Sostenible y de Control de Calidad. Esta propuesta considera un conocimiento razonado de la reactividad química y el diseño de experiencias prácticas representativas de equilibrios químicos en las que se utilicen técnicas comunes pa ra análisis cuantitativo; las experiencias que se proponen fueron diseñadas de acuerdo c on los Principios de la Química Verde buscando iniciar al futuro profesional en el diseño de procesos químicos escalables a nivel industrial y acordes con los requerimi entos de una civilización sostenible; todas fueron probadas y aceptadas por estudiantes de licenciatura y posgrado.

Layered graphene-mica substrates induce melting of DNA origami

Science.gov (United States)

Green, Nathaniel S.; Pham, Phi H. Q.; Crow, Daniel T.; Burke, Peter J.; Norton, Michael L.

2018-04-01

Monolayer graphene supported on mica substrates induce melting of cross-shaped DNA origami. This behavior can be contrasted with the case of origami on graphene on graphite, where an expansion or partially re-organized structure is observed. On mica, only well-formed structures are observed. Comparison of the morphological differences observed for these probes after adsorption on these substrates provides insights into the sensitivity of DNA based nanostructures to the properties of the graphene monolayer, as modified by its substrate.

Caracterização anatômica e química de folhas de Jacaranda puberula (Bignoniaceae presente na Mata Atlântica

Directory of Open Access Journals (Sweden)

Maria Bernadete Gonçalves Martins

Full Text Available A espécie Jacaranda puberula (Bignoniaceae é conhecida popularmente como "carobinha" sendo utilizada na medicina popular em comunidades tradicionais. O objetivo deste trabalho foi realizar a caracterização anatômica e química das folhas de J. puberula. Para a análise anatômica utilizou-se a microscopia de luz e microscopia eletrônica de varredura (MEV. Para a análise química utilizou-se a Cromatografia Líquida de Alta Eficiência (CLAE. O mesofilo é dorsiventral, a epiderme unisseriada com cutícula espessa, tricomas glandulares do tipo peltado e tricomas tectores em ambas as faces da epiderme, parênquima clorofiliano com duas a três camadas de células paliçádicas e quatro a cinco camadas de células formando o parênquima lacunoso, de tamanho pequeno, com muitos espaços intercelulares, hipoestomática com nervura pinada. Os estudos através de MEV evidenciaram a epiderme recoberta com cera epicuticular e glândulas peltadas com maior incidência na epiderme da face abaxial, constituídas por oitos células secretoras apicais. A análise cromatográfica do extrato etanólico evidenciou a presença de fitoquinóides e flavonóides.

Ecología química en el bentos antártico

OpenAIRE

Ballesteros, Manuel (Ballesteros Vázquez); Núñez Pons, Laura; Vázquez, J.; Cristobo, F.J.; Taboada Moreno, Sergio; Figuerola Balañá, Blanca; Ávila Escartín, Conxita

2011-01-01

El estudio de las interacciones entre los organismos mediadas por sustancias químicas, lo que se denomina ecología química, nos da información sobre la biología de las especies implicadas, el funcionamiento de la comunidad en que viven y nos puede proporcionar además el conocimiento de nuevas sustancias que pueden ser útiles para el ser humano. En el marco de nuestros estudios sobre la ecología química de los invertebrados antárticos, en el proyecto ECOQUIM (2003-2006) se recolectaron numeros...

Caracterización química de la cerámica arqueológica de Cotahuasi mediante análisis por activación neutrónica

OpenAIRE

Bedregal, Patricia; Mendoza, Pablo; Ubillús, Marco; Montoya, Eduardo

2010-01-01

Se ha determinado las concentraciones de As, Ba, Ce, Co, Cr, Cs, Eu, Fe, Hf, La, Na, Rb, Sb, Sc, Sm, Th, Yb, en 121 fragmentos de cerámicos arqueológicos encontrados en el valle de Cotahuasi, mediante análisis por activación neutrónica instrumental, según el método k-subcero. Se ha comparado los resultados con la composición química elemental de la cerámica Tiwanaku y la cerámica Wari de Ayacucho y Cusco, encontrándose que los grupos de Ayacucho, Cotahuasi, Cusco y Tiwanaku se encuentran sepa...

Farmacogenómica: Aplicaciones cardiovasculares

Directory of Open Access Journals (Sweden)

Luis Quiñones S., PH.D.

2015-03-01

Este trabajo pretende dar una visión general acerca de farmacogenómica cardiovascular y la posibilidad de utilizar, en la consulta clínica, herramientas genéticas para apoyar la decisión farmacoterapéutica, con el objeto de mejorar la respuesta al tratamiento de enfermedades cardiovasculares, un paso hacia la medicina personalizada en Chile.

Interacciones sociales y explotación económica

Directory of Open Access Journals (Sweden)

Andrés Montaña

2012-01-01

se desarrollan interacciones sociales. El modelo permite identificar la posición de un agente en el espacio social y hacer comparaciones interpersonales. A partir del modelo de interacción social general, planteo un modelo de explotación económica. Una autoridad desde este modelo de explotación puede establecer áreas de restricción para determinar la explotación económica de los agentes. El cálculo de las dotaciones y las combinaciones de éstas, pueden permitir a una autoridad determinar si existe o no explotación de unos agentes por otros, fijar categorías de explotación, e identificar áreas de atención prioritarias. El modelo se podría constituir en una herramienta más apropiada para la identificación de la condición laboral o económica de los niños y niñas.

Antropología Económica: una Reseña Introductoria

Directory of Open Access Journals (Sweden)

Norberto G. Demonte

2007-12-01

Full Text Available El artículo expone las principales perspectivas teóricas de la antropología económica, entendida como el estudio de los procesos de producción, distribución, circulación y consumo enlas sociedades precapitalistas. Se presenta a la antropología económica comoun área de complementación de esfuerzos entre economistas, historiadores y antropólogos, resaltando su importancia en las facultades de ciencias económicas. Se comentan brevemente las cuestiones fundamentales de esta ciencia,tales como la discusión sobre el carácter abstracto de la economía, la polémica entre sustantivistas y formalistas, los aportes dediversos estudios etnográficos, la perspectiva de la escuela marxista y la controversia entre materialistas y culturalistas. Finalmente, el trabajo detalla las líneas de investigación en América Latina y en Argentina y brinda una abundante bibliografía para profundizar los aspectos de interés para el investigador.

Diagenetic replacement of Micas by Carbonates

NARCIS (Netherlands)

Oele, E.

1961-01-01

In the Ordovician sandstones of the Cantabrian Mountains a replacement of the micas by carbonate minerals could be observed. The absence of metamorphic minerals suggests a diagenetic replacement. This is supported by the finding of the same type of replacement in some undisturbed Pliocene sediments

CARACTERIZAÇÃO ANATÔMICA E HISTOQUÍMICA DAS FOLHAS DE EUGENIA UNIFLORA L.

Directory of Open Access Journals (Sweden)

Rafaela Damasceno Sá

2016-10-01

Full Text Available Eugenia uniflora L., popularmente conhecida como pitangueira, é uma importante frutífera muito utilizada na medicina tradicional brasileira para o tratamento de diarreia e disenteria, gripe, parasitas intestinais, febre, hipertensão e como calmante e diurético. Devido ao seu amplo interesse popular e com o intuito de ampliar as informações farmacobotânicas da espécie, este trabalho tem como objetivo realizar a caracterização anatômica e histoquímica das folhas de E. uniflora. Foram confeccionadas e analisadas em microscópico de luz lâminas semipermanentes contendo secções transversais de pecíolo e lâmina foliar, além de secções paradérmicas de lâmina foliar. Realizou-se também testes histoquímicos em secções transversais de lâmina foliar A análise microscópica permitiu a identificação de estruturas importantes na diagnose da espécie: cavidades secretoras no pecíolo e na lâmina foliar; cristais prismáticos no floema do pecíolo e da lâmina foliar, bem como no mesofilo e nas células parenquimáticas e colenquimáticas da nervura central; drusas estão presentes apenas no parênquima do pecíolo e no mesofilo, parênquima e colênquima da lâmina foliar; presença de cutícula espessa no pecíolo e na lâmina foliar; feixes vasculares bicolaterais e mesofilo dorsiventral, com parênquima paliçádico bisseriado. Através da histoquímica evidenciou-se na lâmina foliar a presença de compostos fenólicos, taninos, lignina, compostos lipofílicos, óleos essenciais, triterpenos e esteroides e cristais de oxalato de cálcio. Os resultados apresentados são úteis para a identificação correta da espécie.

A COMPLEXIDADE ECONÔMICA DOS DIREITOS HUMANOS: UMA DIMENSÃO ESCONDIDA DO DESENVOLVIMENTO HUMANO

Directory of Open Access Journals (Sweden)

Leilane Serratine Grubba

2012-10-01

Full Text Available Este artigo tem por objeto a complexidade econômica dos direitos humanos, mais precisamente, a investigação da relação entre a complexidade econômica e o desenvolvimento humano. Nesse sentido, objetivou demonstrar a intrínseca relação e dependência do desenvolvimento humano à complexidade econômica dos direitos humanos, que influi na positivação dos direitos, assim como na luta pelo acesso aos bens necessários a uma vida digna. Por meio do método dedutivo, o artigo problematizou a relação entre o ser humano e seu contexto econômico-social para o desenvolvimento da vida em dignidade. Diante disso, em primeiro lugar, foi apresentada a noção de complexidade dos direitos humanos, isto é, as suas múltiplas dimensões. No segundo momento, foi analisada a questão econômica do desenvolvimento humano, ou seja, a relação entre o desenvolvimento da vida digna e a dimensão econômica da sociedade, e, finalmente, foi apresentada a complexidade econômica dos direitos humanos. O desenvolvimento humano não está apenas vinculado à dimensão econômica, mas compreende todas as dimensões (complexidade que perfazem uma vida digna de ser vivida. A vida se desenvolve em dignidade mediante o acesso aos bens materiais e imateriais. As políticas do desenvolvimento humano, nesse sentido, devem se integrar a uma estrutura que apoie um crescimento com equidade e sustentabilidade. Palavras-chave: Pensamento complexo. Complexidade econômica. Direitos humanos. Desenvolvimento humano. Dignidade humana.

Síntesis y Caracterización de Microesferas Cerámicas

NARCIS (Netherlands)

Quercia Bianchi, G.

2007-01-01

El presente estudio se basó en la utilización de materiales de desecho tipo escoria, para la producción de microesferas cerámicas de bajo costo, con el objetivo principal de profundizar en las metodologías de producción de estas a escala nacional. Generalmente las microesferas cerámicas son

VARIABLES MACROECONÓMICAS Y MICROECONÓMICAS QUE INFLUYEN EN LA ESTIMACIÓN DEL COSTO DE CAPITAL: UN ESTUDIO DE CASO

Directory of Open Access Journals (Sweden)

DANIEL CARDONA ECHEVERRI

2017-01-01

Full Text Available Este artículo identifica y contrasta la significancia estadística de variables macroeconómicas y mi- croeconómicas, que desde la teoría pueden influir sobre el costo de capital. Utilizando información de las empresas listadas en la Bolsa de Valores de Colombia (BVC entre los periodos 2003-4 a 2012-1 y modelos de paneles dinámicos para explicar el Costo de Capital Promedio Ponderado (WACC, se encuentra que la mayoría de las variables propuestas resultan estadísticamente significativas, así mismo se prueba la e xistencia de inercia entre el costo de capital actual y el del periodo pasado.

Cerámicas Estampilladas de Salvatierra de Tormes (Salamanca. Contribución al Estudio de las Cerámicas Tardorromanas del Valle del Duero

Directory of Open Access Journals (Sweden)

Enrique CERRILLO MARTÍN DE CÁCERES

2009-10-01

Full Text Available Dentro del conjunto de yacimientos del Valle del Duero han sido exhaustivamente analizados diversos materiales en bloque (cuchillos, bronces, vidrios, adornos de uso personal, etc. que ponen de manifiesto una indudable unidad cultural de esta zona en un momento determinado, concretamente en los siglos iv y v d. de C. Sin embargo, y a pesar de que el Prof. Palol promete un estudio sobre las cerámicas tardorromanas de estos yacimientos, añadimos a las ya conocidas un lote bastante homogéneo de cerámicas de factura local, pero que a pesar de ello observan unos caracteres muy concretos e interesantes para el estudio de la cerámica del Duero en estos momentos que siempre han quedado vacíos al clasificar cronológicamente los hallazgos, bien de época romana, o bien de época visigoda.

Measurement of friction force between two mica surfaces with multiple beam interferometry

Directory of Open Access Journals (Sweden)

Jung J.C.

2010-06-01

Full Text Available Friction forces play a crucial role in the tribological behaviour of microcomponents and the application of MEMS products. It is necessary to develop a measurement system to understand and control the material characteristics. In this study, a microscopic measurement system based on multiple beam interferometry is developed to measure the friction force between two mica thin films. Some frictional behaviour between the two mica sheets in contact are reported. The evaluated shear strength of mica agrees well to the existing data. It is possible to use the developed system for micro-tribology study.

La influencia socioeconómica en el comportamiento de juego de preescolares

OpenAIRE

Pfeifer, Luzia Iara; Rombe, Patrícia Gonçalves; Santos, Jair Licio Ferreira

2009-01-01

Considerando que o contexto econômico influencia o brincar de crianças, este trabalho teve por objetivo analisar as diferenças entre os brinquedos utilizados por crianças de duas diferentes classes socioeconômicas. Os dados foram coletados junto a 50 mães de crianças com idade entre três e seis anos, metade pertencentes à classe econômica A2 (Grupo 2), e a outra metade pertencente à classe econômica D (Grupo 1), segundo o Critério Brasil. Os resultados apontam para a existência de diferenças ...

El origen de la cerámica en el Este de Asia

OpenAIRE

Sola Fernández de Zuazo, Garazi

2017-01-01

Este trabajo trata sobre el origen de la cerámica. Las teorías tradicionales situaban esta innovación en el Próximo Oriente durante la “Revolución Neolítica” descrita por Gordon Childe. En cambio, los nuevos descubrimientos realizados en yacimientos del Este de Asia nos muestran que la cerámica apareció varios milenios antes en esta zona. La cerámica más antigua fue hallada en yacimientos en cuevas del sur de China y presenta una cronología varios milenios anterior a la aparición de asentamie...

Molecular regulation of MICA expression after HDAC inhibitor treatment of cancer cells

DEFF Research Database (Denmark)

Jensen, Helle

and NKG2D-ligands are upregulated on the surface of abnormal cells. We have previously shown that cancer cells can be stimulated to express the NKG2D-ligands MICA/B after exposure to HDAC-inhibitors (HDAC-i), an occurrence that is not observed in healthy cells. Here we characterize the molecular signal...... pathways that lead to MICA expression after HDAC-inhibitor treatment of cancer cells. Chelating Calcium with Bapta-AM or EGTA potently inhibited HDAC-inhibitor and CMV mediated MICA/B expression. It was further observed that ER Calcium stores were depleted after HDAC-inhibitor treatment. NF-kB activity can...

Enseñanza de química a alumnos con discapacidad visual

OpenAIRE

Gerson de Souza, M.; Patrícia Neves, R.; Rejane Ferreira, P.

2009-01-01

La educación formal en Brasil tiene como primer principio la “igualdad de condiciones de acceso y permanencia en la escuela” (Brasil, 1996). En este contexto, el proyecto “Enseñanza de Química a Alumnos con Discapacidad Visual” busca desarrollar recursos y metodologías para una enseñanza de Química que atienda alumnos con ceguera o baja visión. En este proyecto, con el objetivo de atender alumnos y profesores de la enseñanza secundaria, iniciamos la adaptación del libro “Química e Sociedade” ...

Aprendizaje autorregulado, metas académicas y rendimiento en evaluaciones de estudiantes universitarios

Directory of Open Access Journals (Sweden)

Marcela Valencia Serrano

2013-01-01

Full Text Available Objetivo. Explorar la relación entre aprendizaje autorregulado, metas académicas y rendimiento en una evaluación académica de ocho estudiantes universitarias. Método. Se realizó una entrevista semi- estructurada, una observación directa de una sesión de estudio y protocolos verbales durante y después de la sesión. Resultados. En relación con las metas académicas, se encontró que tres estudiantes tuvieron u na única orientación a metas de dominio por aproximación, mientras que cinco orien taron a múltiples metas académicas. Respecto al aprendizaje autorregulado, se encontraron estudiantes con b ajos y altos niveles. En la relación entre aprendizaje autorregulado, metas académicas y rendimiento en la evaluación fue posible identificar tres grupos de estudiantes: (a altos niveles de autorregulación y orientación única a metas de dominio por aproximación, (b bajos niveles de autorregulación y múltipl e orientación a metas de dominio y ejecución en tendencias de aproximación y evitación, y (c variaciones en el nivel de autorregulación con múltiple orientación a metas académicas. Todas las estudiantes obtuvieron cali ficaciones aprobatorias en la evaluación, independientemente de su nivel de autorregulación y de la orientaci ón a metas académicas. Conclusión. El abordaje procedimental del aprendizaje autorregulado, en función de las metas académicas, permitió obtener información relevante para la comprensión de este proceso, por lo que se recomienda seguir realizando este tipo de estudios para dar cuenta de los diferentes fu ncionamientos de las estudiantes universitarias en tiempo real, de sus variaciones y relación con otros aspectos motivacionales involucrados en sus procesos de aprendizaje.

Caracterización de la región cromosómica 15q11-q13 del genoma humano. Variabilidad genómica en el autismo e identificación de ncRNAs

OpenAIRE

Cerrato Rivera, Celia

2007-01-01

La tesis doctoral con título "Caracterización de la región cromosómica 15q11-13 del genoma humano. Variabilidad genómica en el autismo e identificación de ncRNAs" se basa en el estudio de la región cromosómica 15q11-q13, centrándonos en los aspectos de la variabilidad genómica y su significado funcional. En la primera parte del estudio buscamos reordenamientos de 15q11-q13 en pacientes con autismo, mediante la genotipación de marcadores microsatélites cubriendo dicha región, y definimos una d...

La industria cerámica brasileña

Directory of Open Access Journals (Sweden)

Pacheco Jordao, M. A.

2001-02-01

Full Text Available Ceramics play an important role in the Brazilian economy, with a participation estimated in 1% of the GNP ( Gross National Product, corresponding to about 6 billion dollars. The abundance of natural raw-materials, alternative energy sources, and the availability of practical technologies within the industrial equipments, caused a rapid evolution of the Brazilian industries, and several types of products from the various ceramic segments attained international quality levels, with significative exportation. He ceramic sector is very diverse and can be divided into the following classes: heavy clay ceramics, wall and floor tiles, refractory materials, sanitary ware, porcelain electric insulators, tableware, decorative china, ceramic filters and reservoirs for domestic use, technical ceramics, and thermal insulators. All these segments exist in Brazil, in a higher or lower stage of development and production capacity. Moreover, there are also manufacturers of synthetic glazes and colorants, plaster of paris, equipments and some auxiliary chemicals. In this paper, an overview of the main Brazilian ceramic segments is presented, excluding the glass, cement, and lime sectors, which, despite being ceramic, are generally treated in separate.

La cerámica juega un papel muy importante para la economía del país brasileño con una participación en el P.I.B (Producto Interior Bruto estimado en el 1%, correspondiendo a cerca de 6 millones de dólares. La abundancia de materias primas naturales, fuentes alternativas de energía y una amplia tecnología incorporada a los equipos industriales, han hecho que las industrias brasileñas evolucionasen rápidamente de forma que muchos tipos de productos de diferentes segmentos de la actividad cerámica alcanzasen niveles de calidad mundial, con cifras apreciables destinadas a la exportación. El sector industrial de la cerámica incluye producciones muy diversificados y puede ser dividido en los siguientes

Broad MICA/B Expression in the Small Bowel Mucosa: A Link between Cellular Stress and Celiac Disease

Science.gov (United States)

Allegretti, Yessica L.; Bondar, Constanza; Guzman, Luciana; Cueto Rua, Eduardo; Chopita, Nestor; Fuertes, Mercedes; Zwirner, Norberto W.; Chirdo, Fernando G.

2013-01-01

The MICA/B genes (MHC class I chain related genes A and B) encode for non conventional class I HLA molecules which have no role in antigen presentation. MICA/B are up-regulated by different stress conditions such as heat-shock, oxidative stress, neoplasic transformation and viral infection. Particularly, MICA/B are expressed in enterocytes where they can mediate enterocyte apoptosis when recognised by the activating NKG2D receptor present on intraepithelial lymphocytes. This mechanism was suggested to play a major pathogenic role in active celiac disease (CD). Due to the importance of MICA/B in CD pathogenesis we studied their expression in duodenal tissue from CD patients. By immunofluorescence confocal microscopy and flow cytometry we established that MICA/B was mainly intracellularly located in enterocytes. In addition, we identified MICA/B+ T cells in both the intraepithelial and lamina propria compartments. We also found MICA/B+ B cells, plasma cells and some macrophages in the lamina propria. The pattern of MICA/B staining in mucosal tissue in severe enteropathy was similar to that found in in vitro models of cellular stress. In such models, MICA/B were located in stress granules that are associated to the oxidative and ER stress response observed in active CD enteropathy. Our results suggest that expression of MICA/B in the intestinal mucosa of CD patients is linked to disregulation of mucosa homeostasis in which the stress response plays an active role. PMID:24058482

Temporal Asymmetry, Entropic Irreversibility, and Finite-Time Thermodynamics: From Parmenides–Einstein Time-Reversal Symmetry to the Heraclitan Entropic Arrow of Time

Directory of Open Access Journals (Sweden)

Wassim M. Haddad

2012-02-01

Full Text Available In this paper, we combine the two universalisms of thermodynamics and dynamical systems theory to develop a dynamical system formalism for classical thermodynamics. Specifically, using a compartmental dynamical system energy flow model we develop a state-space dynamical system model that captures the key aspects of thermodynamics, including its fundamental laws. In addition, we establish the existence of a unique, continuously differentiable global entropy function for our dynamical system model, and using Lyapunov stability theory we show that the proposed thermodynamic model has finite-time convergent trajectories to Lyapunov stable equilibria determined by the system initial energies. Finally, using the system entropy, we establish the absence of Poincaré recurrence for our thermodynamic model and develop clear and rigorous connections between irreversibility, the second law of thermodynamics, and the entropic arrow of time.

Caracterização fitoquímica e físico-química das folhas de Bauhinia forficata Link coletada em duas regiões brasileiras

Directory of Open Access Journals (Sweden)

Graziella Silvestre Marques

2012-01-01

Full Text Available Folhas da espécie vegetal Bauhinia forficata Link, popularmente conhecida como pata de vaca, apresentam amplo potencial terapêutico no tratamento do diabetes mellitus. Amostras desta espécie vegetal, obtidas em duas regiões do Brasil (Minas Gerais e Paraná, foram submetidas à caracterização fitoquímica e físico-química (granulometria, perda por dessecação, teor de cinzas e teor de extrativos para realização de um estudo comparativo entre indivíduos cultivados em regiões distintas, bem como estabelecimento de especificações para seu controle de qualidade. Para a caracterização fitoquímica, extratos metanólicos das amostras foram avaliados através de cromatografia de camada delgada (CCD para pesquisa das principais classes de metabolitos secundários. Enquanto que, para as análises físico-químicas foram adotadas metodologias farmacopeicas. A análise estatística dos dados realizouse através dos testes F de Fischer e t de Student. De acordo com a avaliação fitoquímica foi possível observar um perfil similar para ambas as amostras com presença dos seguintes grupos: flavonóides, proantocianidinas, leucoantocianidinas, triterpenos, esteróides, açúcares redutores, além de substâncias antioxidantes com bandas coincidentes às dos compostos flavonoídicos. Por outro lado, as amostras apresentaram algumas propriedades físico-químicas diferentes tais como granulometria e umidade residual em virtude da origem e do processamento adotados pelos fornecedores. Já os valores do teor de cinzas mostraram-se dentro das especificações e não foi observada diferença significativa para o teor de extrativos. Os resultados obtidos neste trabalho contribuíram no processo de identificação e padronização de parâmetros de qualidade para as folhas de B. forficata.

Influence of the surface free energy of silane-coupled mica substrate on the fixing and straightening of DNA

International Nuclear Information System (INIS)

Sasou, Megumi; Sugiyama, Shigeru; Ishida, Takao; Ohtani, Toshio; Miyake, Koji

2009-01-01

Methyltrimethoxysilane (MTMS)-coupled mica substrate is reportedly suitable for fixing and straightening of DNA, but 3-aminopropyltriethoxysilane (APTES)-coupled mica substrate has been found less suitable. On MTMS-coupled mica substrate, the straightness of fixed DNA was sufficient, and the adsorption of contaminants was not observed using fluorescence microscopy and atomic force microscopy. For the APTES-coupled mica substrate, however, aggregated or curved DNA and adsorption of contaminants were observed. To clarify the surface factors that are responsible for this suitability, we analyzed the surface free energies of these substrates using the extended Fowkes theory. In each of the surface free energy components, the dispersion force component in the MTMS-coupled mica substrate was lower than that in the APTES-coupled mica substrate. The ratio of the polar force component on the MTMS-coupled mica substrate was about one order of magnitude on the APTES-coupled mica substrate. In addition, the ratio of the hydrogen-bonding force component for the MTMS-coupled mica substrate was about two times larger than that of the APTES-coupled mica substrate. These results suggest that the polar force and hydrogen-bonding force components are important factors for the fixation and straightening of DNA and that the dispersion force components influence the production and adsorption of contaminants.

La Alianza del Pacífico y Mercosur: evidencias de convergencia económica

Directory of Open Access Journals (Sweden)

José Ustorgio Mora Mora

2016-10-01

Full Text Available Mediante el cálculo de un índice de convergencia económica y el análisis de correlaciones entre varias variables macroeconómicas, se estudia la posibilidad de convergencia económica entre los países miembros de la Alianza del Pacífico con los de Mercosur. Para ello se utiliza información estadística del periodo 1980-2014. A partir de lo anterior, los resultados no son concluyentes, no es posible determinar el rumbo a seguir por estos dos acuerdos para una expansión y una mayor integración económica, aunque los patrones observados sobre las decisiones de los países miembros para este objetivo sugieren que esta pudiera ser bastante factible en el mediano plazo y el índice de convergencia económica refleja esa tendencia. Sin embargo, el análisis de correlaciones no permite establecer una conclusión definitiva.

Não-linearidades: da dinâmica do simples à dinâmica do complexo

Directory of Open Access Journals (Sweden)

José Roberto Castilho Piqueira

1994-01-01

Full Text Available Foram apresentados alguns conceitos relativos à utilização da Teoria dos Sistemas Dinâmicos em problemas de sistemas complexos. A apresentação destes conceitos centra-se no estabelecimento de duas dinâmicas: uma de curto termo e outra de longo termo, relacionando-as com os processos de organização dos sistemas.

Association of MICA gene polymorphisms with liver fibrosis in schistosomiasis patients in the Dongting Lake region

Energy Technology Data Exchange (ETDEWEB)

Gong, Zheng; Luo, Qi-Zhi; Lin, Lin [Department of Immunology, College of Basic Medical Sciences, Central South University, Changsha, Hunan Province (China); Su, Yu-Ping; Peng, Hai-Bo [Central Blood Bank in Yueyang, Yueyang, Hunan Province (China); Du, Kun; Yu, Ping [Department of Immunology, College of Basic Medical Sciences, Central South University, Changsha, Hunan Province (China); Wang, Shi-Ping [Key Laboratory of Schistosomiasis in Hunan, Department of Parasitology, College of Basic Medical Sciences, Central South University, Changsha, Hunan Province (China)

2012-03-02

Major histocompatibility complex class I chain-related A (MICA) is a highly polymorphic gene located within the MHC class I region of the human genome. Expressed as a cell surface glycoprotein, MICA modulates immune surveillance by binding to its cognate receptor on natural killer cells, NKG2D, and its genetic polymorphisms have been recently associated with susceptibility to some infectious diseases. We determined whether MICA polymorphisms were associated with the high rate of Schistosoma parasitic worm infection or severity of disease outcome in the Dongting Lake region of Hunan Province, China. Polymerase chain reaction-sequence specific priming (PCR-SSP) and sequencing-based typing (SBT) were applied for high-resolution allele typing of schistosomiasis cases (N = 103, age range = 36.2-80.5 years, 64 males and 39 females) and healthy controls (N = 141, age range = 28.6-73.3 years, 73 males and 68 females). Fourteen MICA alleles and five short-tandem repeat (STR) alleles were identified among the two populations. Three (MICA*012:01/02, MICA*017 and MICA*027) showed a higher frequency in healthy controls than in schistosomiasis patients, but the difference was not significantly correlated with susceptibility to S. japonicum infection (Pc > 0.05). In contrast, higher MICA*A5 allele frequency was significantly correlated with advanced liver fibrosis (Pc < 0.05). Furthermore, the distribution profile of MICA alleles in this Hunan Han population was significantly different from those published for Korean, Thai, American-Caucasian, and Afro-American populations (P < 0.01), but similar to other Han populations within China (P > 0.05). This study provides the initial evidence that MICA genetic polymorphisms may underlie the severity of liver fibrosis occurring in schistosomiasis patients from the Dongting Lake region.

Association of MICA gene polymorphisms with liver fibrosis in schistosomiasis patients in the Dongting Lake region

International Nuclear Information System (INIS)

Gong, Zheng; Luo, Qi-Zhi; Lin, Lin; Su, Yu-Ping; Peng, Hai-Bo; Du, Kun; Yu, Ping; Wang, Shi-Ping

2012-01-01

Major histocompatibility complex class I chain-related A (MICA) is a highly polymorphic gene located within the MHC class I region of the human genome. Expressed as a cell surface glycoprotein, MICA modulates immune surveillance by binding to its cognate receptor on natural killer cells, NKG2D, and its genetic polymorphisms have been recently associated with susceptibility to some infectious diseases. We determined whether MICA polymorphisms were associated with the high rate of Schistosoma parasitic worm infection or severity of disease outcome in the Dongting Lake region of Hunan Province, China. Polymerase chain reaction-sequence specific priming (PCR-SSP) and sequencing-based typing (SBT) were applied for high-resolution allele typing of schistosomiasis cases (N = 103, age range = 36.2-80.5 years, 64 males and 39 females) and healthy controls (N = 141, age range = 28.6-73.3 years, 73 males and 68 females). Fourteen MICA alleles and five short-tandem repeat (STR) alleles were identified among the two populations. Three (MICA*012:01/02, MICA*017 and MICA*027) showed a higher frequency in healthy controls than in schistosomiasis patients, but the difference was not significantly correlated with susceptibility to S. japonicum infection (Pc > 0.05). In contrast, higher MICA*A5 allele frequency was significantly correlated with advanced liver fibrosis (Pc < 0.05). Furthermore, the distribution profile of MICA alleles in this Hunan Han population was significantly different from those published for Korean, Thai, American-Caucasian, and Afro-American populations (P < 0.01), but similar to other Han populations within China (P > 0.05). This study provides the initial evidence that MICA genetic polymorphisms may underlie the severity of liver fibrosis occurring in schistosomiasis patients from the Dongting Lake region

Effect of synthetic mica on the thermal properties of poly(lactic acid

Directory of Open Access Journals (Sweden)

Diego Holanda Saboya Souza

2014-01-01

Full Text Available Poly(lactic acid/Somasif fluoromica nanocomposites were prepared by melt blending and their thermal properties investigated by DSC, TGA and DMA. Three different types of synthetic mica (Somasif ME-100, Somasif MAE and Somasif MPE were used at different contents (2.5, 5.0 and 7.5 wt %. The melt blending of PLA and these micas is characterized by a considerable reduction in the matrix molecular weight, which decreases when the nanofiller content is increased. For all nanocomposites, the thermal stability increases when mica is added to the polymer, with the Somasif MPE, producing the highest increase of the degradation temperature and highest reduction of Tg.

Otra ciencia económica

Directory of Open Access Journals (Sweden)

Daniel Innerarity

2012-04-01

Full Text Available El autor hace una crítica a la pretensión de la ciencia económica de constituirse como un saber exacto e hiperespecializado al considerar que esta pretensión se ha traducido en una pérdida de la capacidad que es necesaria para comprender la complejidad social de las realidades económicas. Seducida por el objetivo de la exactitud, la economía parece haber olvidado su carácter de construcción social. Además, la economía ha olvidado que es una más entre las ciencias sociales y el largo periodo en el que se ha separado de ellas reivindicando su plena autonomía no ha sido satisfactorio ni para ella ni para el resto de las ciencias sociales. Según el autor la crítica al capitalismo contemporáneo, si quiere ser más radical que moralizante, debe dirigirse a combatir el supuesto realismo de la ciencia económica dominante.The author criticizes the pretension of economic sciences of being an exact science and its tendency to specialization. The consequences of those pretensions are a loss of its capacity to understand the social complexity of the economic realities. The economy, seduced by its aim of exactitude, seems to forget that it is a social construction. Moreover, economy seems to forget that it is just a social science, and for a long period of time economy evolved as a separated and autonomous science; that time was not good neither for economic science neither for social sciences in general. According to the author, if we want to build a more radical and not only moralizing critique to contemporary capitalism, we must criticize the hypothetical realism of the economic science. 

Chemical and physical characterization of fruits of different tomato accessions in the greenhouse. = Caracterização química e física de frutos de diferentes acessos de tomateiro em casa de vegetação.

Directory of Open Access Journals (Sweden)

Ataiza de Andrade Sousa

2011-08-01

Full Text Available Tomato (Solanum lycopersicon is cultivated on a large scale in Brazil and worldwide. Due to the fact that it has a relatively short cycle and higher yields, the tomato crop has good economic prospects and the cultivated area is increasing dayle. The aim of this study was to evaluate the physical and chemical characteristics of fruits of different tomato accessions in the greenhouse conditions in Boa Vista-RR. The following accessions were evaluated: 18 (cherry tomato, 209 (cherry tomato,243 (CNPH 738, 101 (tomato Santa Cruz - KADA, 102 (tomato Yoshimatsu, and 246 (CNPH 0171. The experiment was conducted in a completely randomized design with six treatments and four replications. The fruit at the point of harvest, were collected properly identified and evaluated for the following characteristics: vitamin C content, pH, acidity, soluble solids, soluble solids /acidity, fresh, transverse and longitudinal diameter of the fruit, the pericarp thickness and dry matter content. The data were subjected to variance analysis and means were compared by Duncan test at 5% probability. Except for the variable content of soluble solids, the other variables showed statistical differences. All accesses have attributes suitable for eating raw. With the exception of access 101 and 102 due to high pH (Access 101 and low dry matter content (access 101 and 102, others have attributes suitable for industrial processing.=O tomate (Solanum lycopersicon é cultivado em grande escala na agricultura brasileira sendo uma das culturasmais difundidas em todo mundo. Por se tratar de uma cultura de ciclo relativamente curto e de altos rendimentos, a culturado tomate tem boas perspectivas econômicas e a área cultivada vem aumentando a cada dia. Objetivou-se com este trabalhoavaliar as características físicas e químicas de frutos de diferentes acessos de tomateiro nas condições de casa de vegetação emBoa Vista-RR. Foram avaliados seis acessos, sendo: 18 (tomate cereja

Towards completely miscible PMMA nanocomposites reinforced by shear-stiff, nano-mica.

Science.gov (United States)

Ziadeh, Mazen; Weiss, Stephan; Fischer, Bianca; Förster, Stephan; Altstädt, Volker; Müller, Axel H E; Breu, Josef

2014-07-01

Optimizing the reinforcement of polymers with nanoplatelets requires optimization of the aspect ratio and the moduli of the filler while providing a complete stress transfer. Employing a novel shear-stiff, nano-mica with large aspect ratio, we focus on maximizing the interfacial interaction between filler and matrix. External surfaces of the nano-mica were selectively modified by a polycationic macro-initiator and two PMMA-polymer brushes of length below and above critical entanglement length, respectively, and the mechanical properties of the three PMMA nanocomposites were measured. The multiple electrostatic anchoring groups of the macro-initiator not only provide reliable adhesion but at the same time allow the variation of the degree of protonation providing a local match between the charge densities of the clay surface and the adsorbed macro-initiator. PMMA coating of the nano-mica via surface initiated polymerization yielded long-term stable suspensions in THF that showed birefringence of a nematic phase. Solution blending of the PMMA coated nano-mica allows for dispersing single clay tactoids in the translucent PMMA nanocomposites at 5 wt% clay loading as determined by transmission electron microscopy (TEM). Although significantly improved mechanical properties could be achieved as compared to nanocomposites made with conventional clay fillers, the full potential - as expressed by Halpin-Tsai equations - of the PMMA coated nano-mica can still not be completely utilized. This is attributed to the non-wetting character of the densely packed PMMA brushes attached to planar nanoplatelets. Copyright © 2014 Elsevier Inc. All rights reserved.

Nutrigenómica, obesidad y salud pública.

Directory of Open Access Journals (Sweden)

Manuela Belén Silveira

2007-01-01

Full Text Available El desarrollo de la genómica funcional en los próximos años condicionará cambios en el conocimiento teórico y la práctica clínica de la nutrición. La posibilidad de determinar el perfil genético de un individuo (variaciones genéticas y modificaciones epigenéticas y de conseguir la integración de estos datos en una compleja red de interacciones metabólicas constituye un desafío sin precedentes en la nutrición humana. La aplicación práctica del conocimiento científico puro derivado de la nutrigenómica, en términos de prevención y tratamiento de la obesidad, la DM2 y las enfermedades cardiovasculares, y sus implicaciones en la salud pública, son en este momento todavía indeterminadas. La posibilidad de una intervención nutricional en periodos críticos del desarrollo y la capacidad de modificar la susceptibilidad genética a ciertas enfermedades a través de la alimentación es el gran reto de la nutrigenómica, más allá del diseño de dietas o alimentos funcionales “personalizados”.

Análise das variações anatômicas do canal da mandíbula encontradas em radiografias panorâmicas

Directory of Open Access Journals (Sweden)

Yza Daniella Nunes Andrade

Full Text Available INTRODUÇÃO: No âmbito da clínica odontológica, o bloqueio do nervo alveolar inferior é o mais utilizado; todavia, diversos estudos têm mostrado as mais altas taxas de fracasso, as quais, normalmente, têm como motivo a falha na observação da posição, da forma e da anatomia dos nervos. Essas falhas decorrentes da variação anatômica do nervo alveolar inferior já vêm sendo estudadas na literatura, através de estudos com a análise de radiografias panorâmicas, como proposto neste estudo. OBJETIVO: O objetivo deste estudo foi verificar a ocorrência e a prevalência das variações anatômicas, bem como a correlação das variações do canal da mandíbula com lado e sexo, que podem ocorrer no canal mandibular, por meio de radiografias panorâmicas de pacientes atendidos no Departamento de Odontologia da Universidade Federal de Sergipe (UFS. MATERIAL E MÉTODO: Foram analisadas 1.500 radiografias panorâmicas de pacientes atendidos pelo Departamento de Odontologia da Universidade Federal de Sergipe (UFS. Imagens radiográficas foram observadas sobre um negatoscópio, utilizando-se uma máscara preta ao redor das radiografias, em ambiente com luminosidade apropriada. RESULTADO: Neste estudo, foram observados 5,3% de bifurcações do canal mandibular; 47,5% de canais altos; 16,8% de canais intermediários; 27,1% de canais baixos, e 8,6% de canais com outras variações. CONCLUSÃO: Baseando-se na altura do canal mandibular, houve maior prevalência dos canais altos do que os demais nas mulheres, sendo que não houve diferenças entre os gêneros com relação aos demais tipos e lados afetados. Na classificação dos canais bífidos, não houve diferença estatisticamente significante entre homens e mulheres. Observou-se que a maior prevalência foi para canais sem bifurcação.

Bombacaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available En este trabajo, la familia Bombacaceae es considerada aparte de las Malvaceae, con la cual se considera forma un grupo natural (ver Judd et al. 1997 y la página de internet de Angiosperm Phylogeny Group. En el Perú, las Bombacaceae incluyen 15 géneros y 56 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, generalmente árboles. Siete especies en cinco géneros son endemismos del país. Estas especies endémicas ocupan principalmente las regiones Bosques Secos y Bosques Húmedos Amazónicos, entre los 1300 y 3000 m de altitud. Se aplicaron las categorías y criterios de la UICN a cuatro especies. Ninguna de las Bombacaceae endémicas está representada en el Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Temas de Física para Ingeniería: Segundo principio de la termodinámica

OpenAIRE

Beléndez Vázquez, Augusto

1992-01-01

Acústica, fluidos y termodinámica: "Segundo principio de la termodinámica". Necesidad y enunciado del segundo principio. Rendimiento de las máquinas térmicas y frigoríficas. Ciclo de Carnot. Escala termodinámica de temperaturas. Entropía. Variaciones de entropía en procesos reversibles e irreversibles. Entropía y segundo principio.

Recubrimientos por PVD decorativos sobre cerámicas

Directory of Open Access Journals (Sweden)

García, J. A.

2006-08-01

Full Text Available During the last years PVD coatings has been used for decorative purposes on ceramics and other substrates. Standards layers like TiN, CrN, TiCN, etc, give us the possibly of obtaining a wide range of colours, with a good mechanical, chemical properties. This paper gathers the works carried out in the Center of Advance Surface engineering of AIN during the three last years in the field of the decorative coatings. Different layer have been deposited by means of a METAPLAS 232 PVD equipment. A complete chemical and mechanical characterisation have been carried out on the different deposited layers like ultramicroindentation, scratch tests, wear resistance and GDOES.

En los últimos años se ha venido estudiado la aplicabilidad de las técnicas de depósitos mediante métodos físicos en fase vapor (PVD, para la realización de recubrimientos sobre cerámicas y otros substratos con fines decorativos. Los recubrimientos estándar por PVD como el TiN, CrN, TiCN, etc, ofrecen la posibilidad de conseguir acabados de apariencia metálica, de una amplia gama de colores, y con buenas propiedades mecánicas y químicas, como resistencia a la abrasión, estabilidad térmica, o resistencia a la corrosión. En este trabajo se recogen las experiencias realizadas en el recubrimiento y caracterización de cerámicas decorativas, durante los tres últimos años, en el Centro de Ingeniería de Superficies de la Asociación de la Industria Navarra. Los distintos tipos de recubrimientos se han realizado mediante un equipo de PVD modelo METAPLAS 232, con seis evaporadores de arco eléctrico y sistema de limpieza iónica patentado AEGD. Los recubrimientos han sido caracterizados, tanto química como mecánicamente, empleando las más modernas técnicas tribológicas (ultramicrodureza, scrascth tests, resistencia al desgaste... y espectroscópicas óptica por descarga luminiscente (GDOES. Los resultados obtenidos muestran que las técnicas de PVD son una

Sumérgete en la Bioquímica

Directory of Open Access Journals (Sweden)

Josep M. Fernández Novell

2013-11-01

Full Text Available Hace ya dos años que el Departamento de Bioquímica y Biología Molecular de la Universidad de Barcelona con la colaboración de la SEBBM viene realizando anualmente unas sesiones prácticas de Bioquímica “Sumérgete en la Bioquímica”. Sesiones de mañana o de tarde dirigidas a los jóvenes de tercero y cuarto de la Enseñanza Secundaria Obligatoria (ESO. Estos jóvenes han recibido una información exhaustiva sobre qué es y de qué trata la Bioquímica, al mismo tiempo, han realizado una serie de experimentos en el laboratorio. En éstos, además de aprender las normas de seguridad, cómo utilizar el material volumétrico y las pipetas automáticas, han experimentado sobre: la obtención de ADN de vegetales, cómo medir la concentración de glucosa o de proteína de una muestra utilizando un espectrofotómetro, la producción de una proteína como la GFP en bacterias y las condiciones de precipitación de la caseína de la leche. También, desde Internet, han trabajado sobre cómo extraer el ADN humano y cómo clonar un ratón. Al finalizar cada sesión se recogieron dos tipos de encuestas, una dirigida al alumnado y la otra al profesorado de secundaria para saber el grado de aceptación de dicha actividad. El resultado de unas y otras indica que para todos ellos han sido unas actividades muy apreciadas e interesantes que sirven para aumentar el interés de los estudiantes hacia las ciencias y hacia la Bioquímica en particular. Esta experiencia se ha desarrollado en los laboratorios del Departamento de Bioquímica y Biología Molecular de la UB durante dos semanas entre el mes de Enero y el de Febrero época en que no están ocupados por la enseñanza habitual del Departamento. Este último curso han participado más de 750 estudiantes, la demanda ha superado nuestras previsiones obligándonos a preparar una tercera semana para el curso 2013-2014.

Química recreativa i eines 2.0 per a la didàctica i divulgació de la química

OpenAIRE

Vieta i Corcoy, Pep Anton; Guillaumes, Laia; Güell, Mireia; Duran, Josep; Simon, Sílvia

2012-01-01

Que la societat sovint té una visió negativa de la química i que la recerca científica que té lloc a les universitats es percep com a llunyana per part de la població són fets coneguts. En aquest article, fruit de la presentació feta per l'autor principal a la VII Trobada de Joves Investigadors dels Països Catalans, organitzada el febrer de 2012 per la Societat Catalana de Química (SCQ), es presenten diversos projectes duts a terme des de la Càtedra de Cultura Científica i Comunicació Digi...

La racionalidad económica y la secularización

Directory of Open Access Journals (Sweden)

ANDRÉS BILBAO

1996-01-01

Full Text Available La racionalidad económica es uno de los principales rasgos de la modernidad. Esta racionalidad es, aparentemente, resultado de la ruptura con la vieja superstición religiosa. Sin embargo, sus raíces están en ese mundo religioso, que cree haber superado. en este sentido, el proceso de secularización, del que nace la moderna racionalidad, no es más que la interiorización de los valores religiosos del cristianismo. La creencia de que el individuo, siguiendo sus propios intereses, da lugar a un mundo ordenado, es el rasgo característico de la racionalidad económica. Esta creencia tiene sus raíces en la doctrina cristiana en más de un mundo providencia. El desarrollo de la racionalidad económica no constituye a la superstición religiosa, sino que ella misma, como una nueva forma de superstición, se desarrolla en paralelo con ella.

Catalizadores Organometálicos en la Industria Química

Directory of Open Access Journals (Sweden)

Alfonso Enrique Ramírez Sanabria

2015-10-01

Full Text Available Los procesos catalíticos son cada vez más importantes en la industria. Gran número de productos químicos incluyen dentro de su producción reacciones catalizadas. La catálisis se entiende como un proceso por el cual se aumenta la velocidad de una reacción química, debido a la participación de una especie química denominada catalizador. El presente trabajo recopila cinco procesos industriales en los cuales son empleados catalizadores organometálicos en fase homogénea. Busca resaltar la importancia que tienen los complejosorganometálicos como catalizadores, para la industria de química fina y farmacéutica. Se detallan aspectos mecanísticos en los que se puede ver el papel del centro metálico en las propiedades catalíticas del sistema, así como en la estructura del producto final.

Vida académica de la facultad

Directory of Open Access Journals (Sweden)

Facultad de Medicina Revista

1999-10-01

Full Text Available Distinciones académicas / Novedades docentes / Libro' 'Manual de Rehabilitación Médica" / Texto de Obstetricia y Perinatología / xv Curso Anual Medicina Interna / Libros Publicados en la Facultad de Medicina Universidad Nacional De Colombia, 1999.

On the rare elements geochemistry in mica mega crystals from alkaline basaltoids of Southern Tien-Shane

International Nuclear Information System (INIS)

Mogarovskiy, V.V.; Sharapov, N.V.

1992-01-01

Rare elements without coherent in the mica and basalts are divided in 2 groups: First (K, Rb, Pb) in the first stage of meta soma tos are brought, and located in the mica. The second (Li, Cs, Sn) which brings after micas appearing, using in other minerals and without mineral location

Influence of the nonexchangeable potassium of mica on radiocesium uptake by paddy rice

International Nuclear Information System (INIS)

Eguchi, Tetsuya; Ohta, Takeshi; Ishikawa, Tetsuya; Matsunami, Hisaya; Takahashi, Yoshihiko; Kubo, Katashi; Yamaguchi, Noriko; Kihou, Nobuharu; Shinano, Takuro

2015-01-01

A pot cultivation experiment was conducted to elucidate the influence of the nonexchangeable potassium (K) of mica on radiocesium ( 137 Cs) uptake by paddy rice (Oryza sativa L. cv. Koshihikari), and to evaluate the potential of mica application as a countermeasure to reduce radiocesium transfer from soil to paddy rice. The increase in the exchangeable K concentrations of soils, measured before planting, due to mica (muscovite, biotite, and phlogopite) application was negligible. However, in trioctahedral mica (biotite and phlogopite)-treated soil, the release of nonexchangeable K from the mica interlayer maintained the soil-solution K at a higher level during the growing season in comparison to the control, and consequently decreased the 137 Cs transfer factor for brown rice (TF). The sodium tetraphenylboron (TPB)-extractable K concentration of the soils, measured before planting, was strongly negatively correlated with the TF, whereas the exchangeable K concentration of the soils, also measured before planting, was not correlated with the TF. Therefore, we conclude that TPB-extractable K is more reliable than exchangeable K as a basis of fertilizer recommendations for radiocesium-contaminated paddy fields. Phlogopite-treated soils exhibited higher TPB-extractable K concentrations and lower TF values than biotite-treated soils. We thus conclude that phlogopite application is an effective countermeasure to reduce radiocesium uptake in paddy rice. - Highlights: • Nonexchangeable K of added trioctahedral mica decreased 137 Cs uptake by paddy rice. • TPB-extractable K would be a more reliable indicator than exchangeable K. • Phlogopite would be a good amendment for radiocesium-contaminated paddy fields

Growth of highly textured SnS on mica using an SnSe buffer layer

International Nuclear Information System (INIS)

Wang, S.F.; Fong, W.K.; Wang, W.; Surya, C.

2014-01-01

We report the growth of SnS thin films on mica substrates by molecular beam epitaxy. Excellent 2D layered structure and strong (001) texture were observed with a record low rocking curve full width at half maximum of ∼ 0.101° for the SnS(004) diffraction. An interface model is used to investigate the nucleation of SnS on mica which indicates the co-existence of six pairs of lateral growth orientations and is in excellent agreement with the experimental Φ-scan measurements indicating 12 peaks separated by 30° from each other. To control the lateral growth of the SnS epilayers we investigate the utilization of a thin SnSe buffer layer deposited on the mica substrate prior to the growth of the SnS thin film. The excellent lattice match between SnSe and mica enhances the alignment of the nucleation of SnS and suppresses the minor lateral orientations along the mica[110] direction and its orthogonal axis. Detailed low-frequency noise measurement was performed to characterize the trap density in the films and our results clearly demonstrate substantial reduction in the density of the localized states in the SnS epilayer with the use of an SnSe buffer layer. - Highlights: • A record low rocking curve FWHM for deposited SnS on mica • Investigation of the nucleation of SnS on mica using the interface model • Investigation of nucleation mechanism by phi-scan measurement • Grain boundary formation from crystallites of various nucleation orientations • Suppression of nucleation orientations using an SnSe buffer layer

mica – music information center austria

OpenAIRE

2010-01-01

1994 wurde das österreichische Musikinformationszentrum (mica) im Auftrag des österreichischen Bundesministers für Unterricht und Kunst (Rudolf Scholten) von den Bundeskuratoren für Musik (L. Knessl, Christian Scheib) gegründet (Geschäftsführer 1994–99 Matthias Finkentey, 1999–09 Peter Rantasa, ab 2009 Sabine Reiter).

Temas de Física para Ingeniería: Dinámica del punto material

OpenAIRE

Beléndez, Augusto; Pastor Antón, Carlos; Bernabeu, Guillermo

1988-01-01

Apuntes de Mecánica: "Dinámica del punto material". Introducción, dinámica del punto. Fuerzas en la naturaleza. Sistemas de referencia. Leyes de Newton. Fuerzas de rozamiento. Ley de la gravitación universal. Aplicación de las leyes de Newton a la resolución de problemas de dinámica. Momento lineal y conservación. Redefinición de fuerza. Momento angular y conservación, fuerzas centrales. Impulso mecánico.

Aprendiendo química con golosinas

Directory of Open Access Journals (Sweden)

José Manuel Rodríguez Rodríguez

2011-01-01

Full Text Available Las golosinas (caramelos, chicles, nubes, palotes, papas fritas, etc. nos gustan a casi todos y gozan de una imagen positiva, a pesar de sus efectos secundarios si no se consumen con moderación. Aprovechándonos de esa buena imagen y de la gran variedad de golosinas que existen en el mercado, hemos diseñado una serie de experimentos con los que podemos explicar distintos tipos de reacciones químicas (ácido-base, oxidación reducción, endotérmicas¿, la actuación de un indicador e, incluso, podemos comparar cantidades de vitamina C. En todas las actividades se persigue explicar algún aspecto de la Química que, en general, el público desconoce, captando su atención, por ejemplo, mediante cambios de color espectaculares y con las golosinas como protagonistas. Así mismo, estas experiencias pueden emplearse como recursos didácticos para alumnos de 4º E.S.O. y Bachillerato, apoyando los contenidos teóricos del currículum.

1g(9/2), 1f(5/2), and 1f(7/2) neutron inner hole responses in Sn-115 and Sn-119 via the ((d)over-right-arrow,t) reaction at E-d=200 MeV

NARCIS (Netherlands)

Langevin-Joliot, H; Van de Wiele, J; Guillot, J; Gerlic, E; Rosier, LH; Willis, A; Djalali, C; Morlet, M; Tomasi-Gustafsson, E; Blasi, N; Micheletti, S; van der Werf, SY

Neutron inner hole responses in Sn-115 and Sn-119 nuclei have been studied via the ((d) over right arrow ,t) reaction at E-d=200 MeV using a polarized beam with both vector and tensor components. One-step pickup observables corresponding to the overlapping 1g(9/2), 1f(5/2), and 1f(7/2) responses

Experiments on the incorporation of concentrated solutions of fission products in glasses and micas; Essais d'incorporation de solutions concentrees de produits de fission dans des verres et des micas

Energy Technology Data Exchange (ETDEWEB)

Bonniaud, R; Cohen, P; Sombret, C [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

1) The plants designed for extracting the plutonium of the G1, G2, G3 reactors fuel rods will produce extremely concentrated tions of fission products. 2) Let us consider a synthetic solution of the 'G2' type: (2N NO{sub 3}H - 2,25 meq/cm{sup 3} AI{sup +++} - 5.10{sup -3} {sup 134}Cs - {sup 137}Cs tracer). We made various glasses and micas by adding and mixing the necessary adjuvants and baking (900 to 1400 deg. C) in a graphite crucible. 3) The products obtained had either the shape of a cylindrical pellet or were reduced into a fine powder. They were mixed with 300 cm{sup 3} of synthetic sea water during variable periods of time in order to study leaching of the activity. 4) Experiments were first carried on caesium because of its solubility. 5) Fabrication of micas on a large scale sets many technological problems more difficult to solve (1400 deg. C) than in the case of glasses (1000 deg. C). A comparative study on both micas and glasses showed that leaching of activity was more important in the micas. (author)Fren. [French] 1) La mise en service de l'Usine d'Extraction du Plutonium destinee en particulier au traitement des barres de combustibles de G1, G2, G3 fournira des solutions residuaires concentrees de produits de fission. 2) Partant d'une solution synthetique 'G2': (2N NO{sub 3}H - 2,25meq/cm{sup 3} AI{sup +++} - 5.10{sup -3} {sup 134}Cs - {sup 137}Cs traceur) nous avens realise differents verres et micas apres adduction et melange des adjuvants necessaires suivis de cuisson (900 a 1400 deg. C) dans un creuset de graphite. 3) Les produits obtenus ont ete, soit sous forme d'eprouvette cylindrique, soit sous forme de poudre finement broyee, mis en contact et agites avec 300 cm{sup 3} d'eau de mer synthetique, durant des temps varies pour etudier la retention de l'activite. 4) Le cesium a ete choisi pour ces essais a cause de sa solubilite. 5) La fabrication de micas a grande echelle pose des problemes technologiques plus difficiles (1400 deg. C) a

EL CONGRESO DE KARLSRUHE: PASO DEFINITIVO HACIA LA QUÍMICA MODERNA

Directory of Open Access Journals (Sweden)

Ramón Cid Manzano

2009-01-01

Full Text Available Estamos celebrando en este año 2009 el 140 aniversario de la publicación de la primera tabla periódica y el 90 aniversario de la creación del IUPAC. Ambos acontecimientos se relacionan directamente con el congreso de Karlsruhe llevado a cabo en esa ciudad alemana en 1860. Este congreso fué convocado para que los químicos europeos pudieran discutir sobre asuntos muy controvertidos, como la naturaleza atómica de la materia, la nomenclatura química y los pesos atómicos. El objetivo de este artículo es proporcionar a los lectores algunos datos sobre este congreso para entender mejor cómo la tabla periódica fue desarrollada y cómo la química se convirtió en una ciencia moderna.

El sector inmobiliario y las crisis económicas

Directory of Open Access Journals (Sweden)

Antonio Daher

2013-09-01

Full Text Available La creciente urbanización de la economía y la doble concentración -económica y territorial- de los sectores inmobiliario y financiero en las metrópolis, fundamentan la relación entre los ciclos inmobiliarios y las crisis económicas detonadas por sus burbujas, la alta incidencia macroeconómica del sector inmobiliario y su rol articulador entre el sector financiero y la economía real. Antes de la última crisis (2008, las instituciones financieras y fondos de inversión inmobiliaria transnacionales encontraron en la financiarización y titulización una vía eficaz para su diversificación geográfica y distribución del riesgo hipotecario. Fue también la vía expedita del contagio de una crisis con ubicuidad financiera, aunque no social ni territorial. Las hipotecas subprime fueron para las minorías marginadas en los barrios con más hispanos, negros, inmigrantes y pobres: la vivienda social estadounidense, financiarizada, "inmobiliarizó" al sector financiero y desfinanciarizó la banca internacional, en una crisis global con dramáticas consecuencias sociales y políticas.

MORFOMETRÍA, HIDRODINÁMICA Y FÍSICO-QUÍMICA DEL AGUA DE LA LAGUNA DE CHAUTENGO, GUERRERO, MÉXICO

Directory of Open Access Journals (Sweden)

Rendón-Dircio JA

2012-02-01

Full Text Available Se realizó un estudio del comportamiento de las variables morfométricas, batimétricas, hidrodinámicas y físico-químicas de la Laguna de Chautengo, Guerrero, a partir de fotografías aéreas y trabajo de campo con muestreos bimensuales de variables morfométricas, hidrodinámicas y físico-químicas del agua. Los resultados indicaron que la laguna presentó marcadas variaciones anuales en su morfometría y batimetría. El área máxima estimada fue de 29.6 km2. La barra de la laguna es recta y está colonizada en un 36.8 % por comunidades de manglar, tiene una longitud de 10 km y una anchura media de 0.52 km. Las tres islas que presenta la laguna se ubican cerca de la desembocadura y tienen un área de 83,000, 3,680 y 61,440 m2 respectivamente. La variación vertical de la columna de agua fluctuó entre 6 y 12 cm diarios, presentándose el máximo nivel a las 18:00 y 0:00 h y el mínimo a las 6:00 h. Las corrientes presentaron un valor promedio de velocidad de 1.97 m/min. La temperatura media anual fue de 29.8 oC, con una variación entre la superficie y el fondo de 0.23 oC; la salinidad varió de 0.7 a 38 ‰; el oxígeno disuelto se registró en promedio en 4.71 mg/L, existiendo una diferencia del 8.7 % entre la superficie. La laguna presenta características de un cuerpo de agua somero y tropical en un proceso avanzado de evolución, pero con condiciones adecuadas para el desarrollo de la fauna y flora acuática. Este estudio servirá de base para el diseño de un plan de manejo sostenible de las pesquerías y acuicultura de la Laguna de Chautengo.

Liberalização financeira, performance econômica e estabilidade macroeconômica no Brasil: uma avaliação do período 1994-2007

Directory of Open Access Journals (Sweden)

Luiz Fernando de Paula

2013-05-01

Full Text Available Este artigo objetiva avaliar a relação entre liberalização da conta capital, performance econômica e estabilidade macroeconômica no Brasil. Para tanto, além de uma revisão da literatura, o artigo realiza uma avaliação em-pírica dos efeitos da liberalização financeira no Brasil sobre um conjunto de variáveis macroeconômicas com o uso da metodologia VAR, utilizando, para tanto, dois modelos: um com um índice de jure de liberalização financeira (ILF, e outro com um índice de facto de integração financeira (IIF. Procura-se, no primeiro caso, avaliar a hipótese de que a liberalização financeira resulta em redução no risco país e, consequentemente, na taxa de juros doméstica; no segundo caso, avalia-se a hipótese de que a liberalização financeira tem impacto positivo sobre o crescimento econômico e a estabilidade macroeconômica vis-à-vis à hipótese dos críticos da liberalização financeira de que esta gera efeitos instabilizadores em países em desenvolvimento.

Indiscernibilidade e identidade em química: aspectos filosóficos e formais

Directory of Open Access Journals (Sweden)

Jaison Schinaider

2014-06-01

Full Text Available Neste artigo tratamos, de um ponto de vista formal e filosófico, com alguns conceitos que fazem parte da química usual. As teorias da química, e seus conceitos, normalmente são apresentadas de um ponto de vista informal (não axiomatizada, e isso pode trazer dificuldades filosóficas (embora a química propriamente - bem como também as outras disciplinas da ciência aplicada - pareçam não sofrer qualquer restrição quanto a isso. Aqui estaremos ocupados em um aspecto parti-cu-lar, que diz respeito à indiscernibilidade de alguns objetos básicos da química, tais como átomos, moléculas, bem como de seus componentes. Começamos com uma visão geral da identidade destes compostos e seus componentes a partir de uma perspectiva filosófica e, em seguida, mostramos em que sentido o conceito de identidade dos compostos químicos é problemático em relação ao conceito correspondente de identidade na lógica e matemática clássicas (que, como em geral é suposto, estão 'alicerçando' as teorias químicas. Argumentamos que, por um lado, a química parece supor que esses objetos básicos precisam ser 'idênticos' (indistinguíveis uns aos outros (como enfatizado há muito tempo por John Dalton, como veremos. Por outro lado, do ponto de vista formal, se a lógica subjacente à teoria atômica for a lógica clássica (que também é pano de fundo da matemática padrão, coisas idênticas devem ser a mesma coisa e logo 'colapsar' em apenas uma (e este não é o caso em química, uma vez que temos uma enorme quantidade de átomos e moléculas semelhantes, mas não apenas um. Esta aparente contradição pode ser tratada de várias perspectivas e, aqui, propomos o uso de uma teoria de conjuntos não-clássica (a saber, a teoria de quase-conjuntos para alicerçar uma formulação axiomática de certas teoria químicas, mostrando como essa diferente base matemática pode nos levar a uma visão que está mais perto da química em si. Como esta

Química de Heterociclos

OpenAIRE

Collado, Daniel

2014-01-01

Heterociclos aromáticos con cinco miembros. Pirrol, furano y tiofeno: propiedades. Sustitución electrofílica aromática. Reacciones de los sustituyentes alquílicos. Sustitución nucleofílica. Radicales y carbenos, aperturas de anillo. Síntesis. Capítulo segundo del temario del segundo bloque de la asignatura Ampliación de Química Orgánica Avanzada. Heterociclos aromáticos de cinco miembros.

Cerámicas de circona para aplicaciones biomédicas

OpenAIRE

Delgado García-Menocal, José Angel; Morejón, L.; Martínez, S.; Gil, F. X. (Francesc Xavier)

2003-01-01

Se tratan los aspectos mas significativos de distintos biomateriales empleados para la sustitución del tejido óseo pero haciendo énfasis en las cerámicas de óxido de zirconio (circonas). Se destacan las características de las cerámicas de circona que lo convierten en un material muy atractivo por sus excelentes propiedades mecánicas, en particular su elevada tenacidad a la fractura relacionada con la transformación martensítica que se produce cuando el material es sometido a un...

Van der Waals epitaxy and photoresponse of hexagonal tellurium nanoplates on flexible mica sheets.

Science.gov (United States)

Wang, Qisheng; Safdar, Muhammad; Xu, Kai; Mirza, Misbah; Wang, Zhenxing; He, Jun

2014-07-22

Van der Waals epitaxy (vdWE) is of great interest due to its extensive applications in the synthesis of ultrathin two-dimensional (2D) layered materials. However, vdWE of nonlayered functional materials is still not very well documented. Here, although tellurium has a strong tendency to grow into one-dimensional nanoarchitecture due to its chain-like structure, we successfully realize 2D hexagonal tellurium nanoplates on flexible mica sheets via vdWE. Chemically inert mica surface is found to be crucial for the lateral growth of hexagonal tellurium nanoplates since it (1) facilitates the migration of tellurium adatoms along mica surface and (2) allows a large lattice mismatch. Furthermore, 2D tellurium hexagonal nanoplates-based photodetectors are in situ fabricated on flexible mica sheets. Efficient photoresponse is obtained even after bending the device for 100 times, indicating 2D tellurium hexagonal nanoplates-based photodetectors on mica sheets have a great application potential in flexible and wearable optoelectronic devices. We believe the fundamental understanding of vdWE effect on the growth of 2D tellurium hexagonal nanoplate can pave the way toward leveraging vdWE as a useful channel to realize the 2D geometry of other nonlayered materials.

La superación en gestión académica del directivo universitario

Directory of Open Access Journals (Sweden)

Vicenta Aveiga Macay

2013-12-01

Full Text Available Se planteó como objetivo sistematizar los fundamentos teóricos que sustentan el proceso de superación a directivos universitarios para la gestión académica. Se utilizó métodos del nivel teórico y empírico como el histórico lógico, analítico-sintético, el análisis documental, la observación, el inventario de dificultades, cuestionarios, entrevistas, los cuales posibilitaron caracterizar epistemológicamente el proceso de superación a directivos universitarios con énfasis en la gestión académica, arribar a nuevos conceptos, y distinguir aspectos significativos de la superación a directivos en gestión académica. PALABRAS CLAVES: Directivos, gestión académica, proceso formativo, superación.

Evolución hacia la cerámica fotovoltaica

Directory of Open Access Journals (Sweden)

Sánchez-Muñoz, L.

2011-02-01

Full Text Available Nowadays there are two types of ceramic materials, i.e. traditional and advanced. The origin and development of the first one occurred before the revolutionary changes in Science and Technology of the nineteenth century, while the second one is its direct consequence. The traditional ceramics, which are related primarily to elementary human needs, in particular its constructions, is very homogeneous with respect to their formulations, being their diversity mainly linked to the decorative aspects of one surface. Advanced ceramics are characterized by a wide variety of materials with specific physical and chemical responses to radiation and electromagnetic fields, where major economic benefits are mainly related to secondary human needs such as telecommunications. As a result of the current global crisis, traditional buildings could be rehabilitated and/or replaced by energy efficient buildings, also called zero-energy buildings. In them there is a balance between energy consumed and produced “in situ”, and also using environmentally friendly materials. The direct consequence of this trend will be the evolution of ceramics by partial hybridization of its two ancestors, with special importance of semiconductor compounds, to the production of electrical energy as the basic objective, in this work called photovoltaic ceramics.

Actualmente se distinguen dos tipos de cerámica, una tradicional y otra avanzada. El origen y desarrollo de la primera es anterior a los cambios revolucionarios en Ciencia y Tecnológica del siglo XIX, mientras que la segunda es su consecuencia directa. La cerámica tradicional, que está relacionada sobre todo con las necesidades humanas primarias y en particular a sus construcciones, es muy homogénea respecto a sus formulaciones, estando su diversidad ligada principalmente a los aspectos decorativos de una de sus superficies. La cerámica avanzada se caracteriza por una gran diversidad de materiales con

Dinámica fisicoquímica de las aguas de un sistema de planicies inundables tropicales

Directory of Open Access Journals (Sweden)

Yimmy Montoya M

2013-01-01

Full Text Available Se estudió el cambio de algunas variables fisicoquímicas en el agua de siete caños y siete ciénagas pertenecientes a la zona de planos de inundación de Ayapel en nueve muestreos durante el periodo 2006-2009. El valor medio de la conductividad eléctrica en la ciénaga es tres veces inferior al valor medio de las ciénagas de la región. 100 μS/cm puede considerarse como discriminante entre ciénagas con valores inferiores y los caños con valores superiores. No hubo relación entre la transparencia y la concentración de pigmentos fotosintéticos, lo que podría considerarse como indicador de un nivel de estado trófico bajo del sistema. A nivel temporal todas las formas de nutrientes evaluadas presentaron diferencias lo que indica la importancia del efecto del pulso de inundación a través del ciclo hidrológico. Con la disminución de la columna de agua en época de estiaje, se evidenció un aumento de las concentraciones de nitrógeno, las cuales se ven favorecidas por la resuspensión de material del fondo de la ciénaga. La concentración de fósforo es más sensible a la variación espacial, ya que el ciclo de este nutriente estuvo asociado a los sedimentos y a la composición del suelo de cada microcuenca. Se encontró que para una misma fase del pulso en ciclos sucesivos, se registran diferencias en la dinámica del sistema, por lo que el momento hidrológico en el que se realiza el muestreo es el factor principal en el comportamiento de las condiciones fisicoquímicas del sistema.

La contaminación Química

OpenAIRE

Jimbo G., Marcelo

2003-01-01

La contaminación química de la leche se puede verificar mediante cuatro vías: a. Detergentes y desinfectantes usados en las operaciones de lavado. b.Antielmínticos. c. Insecticidas y anticriptogámicos usados en agricultura. d. Elementos radioactivos, sustancias dicersas, metales.

Influence of the nonexchangeable potassium of mica on radiocesium uptake by paddy rice.

Science.gov (United States)

Eguchi, Tetsuya; Ohta, Takeshi; Ishikawa, Tetsuya; Matsunami, Hisaya; Takahashi, Yoshihiko; Kubo, Katashi; Yamaguchi, Noriko; Kihou, Nobuharu; Shinano, Takuro

2015-09-01

A pot cultivation experiment was conducted to elucidate the influence of the nonexchangeable potassium (K) of mica on radiocesium ((137)Cs) uptake by paddy rice (Oryza sativa L. cv. Koshihikari), and to evaluate the potential of mica application as a countermeasure to reduce radiocesium transfer from soil to paddy rice. The increase in the exchangeable K concentrations of soils, measured before planting, due to mica (muscovite, biotite, and phlogopite) application was negligible. However, in trioctahedral mica (biotite and phlogopite)-treated soil, the release of nonexchangeable K from the mica interlayer maintained the soil-solution K at a higher level during the growing season in comparison to the control, and consequently decreased the (137)Cs transfer factor for brown rice (TF). The sodium tetraphenylboron (TPB)-extractable K concentration of the soils, measured before planting, was strongly negatively correlated with the TF, whereas the exchangeable K concentration of the soils, also measured before planting, was not correlated with the TF. Therefore, we conclude that TPB-extractable K is more reliable than exchangeable K as a basis of fertilizer recommendations for radiocesium-contaminated paddy fields. Phlogopite-treated soils exhibited higher TPB-extractable K concentrations and lower TF values than biotite-treated soils. We thus conclude that phlogopite application is an effective countermeasure to reduce radiocesium uptake in paddy rice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Compreensão econômica de estudantes entre 10 e 15 anos

Directory of Open Access Journals (Sweden)

Sonia Bessa

2014-08-01

Full Text Available Nos últimos 50 anos, ocorreram significativas mudanças sociais, culturais, políticas, econômicas e tecnológicas que afetam o comportamento de pré-adolescentes e jovens. Essa faixa etária necessita de investigações sobre sua compreensão do mundo econômico e o papel da família no processo de socialização econômica. Por isso, a presente pesquisa tem por objetivo principal caracterizar a compreensão econômica de 830 estudantes de 10 a 15 anos de diferentes níveis socioeconômicos, moradores da cidade de São Paulo. O instrumento utilizado foi o Teste de Alfabetização Econômica para crianças, TAE-N. Com abordagem qualitativa e quantitativa, utilizou-se o desenho descritivo-comparativo e correlacional. Apresenta-se a frequência das variáveis categóricas; valores de frequência absoluta, percentual; média e desvio-padrão; utilizou-se o coeficiente alfa de Cronbach; teste Qui-Quadrado. Para a comparação de medidas contínuas ou ordenáveis, valeu-se dos testes Mann-Whitney e Kruskal-Wallis. Os resultados demonstram uma socialização econômica insuficiente para lidar com as exigências do mundo econômico.

EFECTO DE RECUBRIMIENTO NATURAL Y CERA COMERCIAL SOBRE LA MADURACIÓN DEL BANANO (Musa sapientum EFFECT OF NATURAL COATING AND COMMERCIAL WAX ON THE MATURATION OF BANANA (Musa sapientum

Directory of Open Access Journals (Sweden)

PAOLA LYSETH BARCO

2009-12-01

Full Text Available Se evaluó y comparó el efecto de la cera comercial "Cerabrix de Banano" (TAO QUÍMICA LTDA., un recubrimiento natural a base de almidón de yuca hidrolizado y una muestra testigo sobre el pH, la acidez, la firmeza y sólidos solubles del banano (Musa sapientum en estado de madurez organoléptica bajo condiciones ambientales. Se aplicó un diseño experimental completamente al azar con 7 repeticiones por tratamiento y los resultados fueron sometidos a un análisis de varianza, lo cual indicó que el pH y el índice de madurez no se vieron afectados por los tratamientos, considerando como causas de variación el tiempo y los tratamientos aplicados, con una probabilidad del 95%. Los valores promedio significativamente diferentes se compararon mediante la prueba de Duncan, para una probabilidad del 95%, dando como resultado que los bananos cubiertos con Cerabrix tuvieron mayor firmeza, en comparación con el recubrimiento natural.The effect of the commercial wax "Cerabrix of Banana" (TAO QUÍMICA LTDA, a coating based on natural hydrolyzed starch and a blank was evaluated and compared on pH, acidity, firmness and soluble solids of banana (Musa sapientum in state of organoleptic maturity at ambient conditions. An experimental design totally at random with 7 repetitions by treatment was applied and the results were put under a variance analysis, which indicated that the pH and the maturity index were not affected by the treatments, considering variation causes the time and treatments applied, with a probability of 95%. The average values significantly different were compared by the Duncan test for a 95% probability, giving as a result that the bananas covered with Cerabrix had bigger firmness, in comparison with natural coating.

Mastocitosis sistémica: repercusión ósea

Directory of Open Access Journals (Sweden)

Francisco R. Spivacow

2012-06-01

Full Text Available La mastocitosis sistémica es una enfermedad caracterizada por acumulación de mastocitos en varios órganos, de los cuales el más afectado es la piel. La repercusión ósea de esta enfermedad es poco frecuente y en general se la asocia al desarrollo de osteoporosis secundaria con o sin fracturas óseas. Se presentan tres pacientes con lesiones características en piel de mastocitosis y diferentes manifestaciones óseas; el primer caso es una mujer de 51 años en la que se observó una variante esclerosante muy poco frecuente, con densitometría ósea en valores normales-altos y aumento de la densidad ósea observada en varias vértebras por radiografías. Una punción-biopsia de cresta ilíaca confirmó el compromiso óseo de su enfermedad de base. El segundo caso fue una mujer de 57 años que mostró signos característicos de mastocitosis sistémica con diarreas, gastritis, flushes y reacciones cutáneas particulares ante exposición a alérgenos. Se observó además grave disminución de la densidad mineral ósea tanto en columna lumbar como en cuello de fémur con parámetros bioquímicos de aumento de la resorción ósea, por lo que fue necesario tratarla con bisfosfonatos. La tercera paciente, de 67 años de edad, presentó varias fracturas vertebrales, con densitometría ósea levemente disminuida. En esta última paciente se constató una hiperplaquetosis con diagnóstico histológico de trombocitemia esencial, cuadro que suele asociarse a la mastocitosis sistémica. En definitiva, se presentan y discuten tres variantes óseas diferentes de mastocitosis sistémica.

Atomically Thin Mica Flakes and Their Application as Ultrathin Insulating Substrates for Graphene

NARCIS (Netherlands)

Castellanos-Gomez, Andres; Wojtaszek, Magdalena; Tombros, Nikolaos; Agrait, Nicolas; van Wees, Bart J.; Rubio-Bollinger, Gabino; Agraït, Nicolás

2011-01-01

By mechanical exfoliation, it is possible to deposit atomically thin mica flakes down to single-monolayer thickness on SiO(2)/Si wafers. The optical contrast of these mica flakes on top of a SiO(2)/Si substrate depends on their thickness, the illumination wavelength, and the SiO(2) substrate

Dinâmica molecular ab initio:aplicações ao estudo de propriedades electrónicas de sistemas moleculares

OpenAIRE

Martiniano, Hugo Filipe de Mesquita Costa, 1978-

2013-01-01

Tese de doutoramento, Química (Química-Física), Universidade de Lisboa, Faculdade de Ciências, 2013 O método da dinâmica molecular ab initio exibe vantagens significativas para o estudo da estrutura e propriedades electrónicas de sistemas moleculares complexos. No entanto, uma das suas desvantagens é o elevado custo computacional, quando comparado com os métodos de dinâmica molecular clássicos. Um dos modos de resolver este problema é adoptar uma abordagem sequencial, na qual a dinâmica é ...

RELACIONES DE PREFERENCIA Y ELECCIÓN SOCIAL EN UNA ESTRUCTURA DIFUSA

Directory of Open Access Journals (Sweden)

Arcenio Pecha

2002-12-01

Full Text Available Autores como Prasanta Pattanaik [1997] encuentran en la lógica difusa un modo de superar las restricciones de la condición de racionalidad económica neoclásica. Ellos se sirven de este instrumento matemático para hacer una reinterpretación del planteamiento de la elección social que Arrow [1951] modeló con relaciones de preferencia ajustadas a una lógica binaria. El propósito de este trabajo es doble. Por un lado se desarrolla el planteamiento del Teorema de Imposibilidad de Arrow [1951], resaltando la importancia de la transitividad impuesta a las relaciones de preferencia como condición de racionalidad, y mostrando cómo la transitividad adquiere distintas formas cuando se incluyen relaciones de preferencia difusas. De otra parte, se examinan las reglas de agregación y las medidas del consenso propuestas por los autores que estudian la elección social dentro de una estructura difusa.Authors as Prasanta Pattanaik [1997] find in the fuzzy logic a way to go beyond the restrictions of the conditions of neoclassic economic rationality. They use this mathematical tool to reinterpret the social choice proposal, which was modelled by Arrow [1951] with preference relations adjusted to binary logic. This paper has two goals. To begin with, the Arrow´s [1951] approach of the Impossibility Theorem is developed. It gives importance to the transitivity condition imposed to preference relations as a condition for rationality and shows how this condition acquires different forms when fuzzy preference relations are used. On the other hand, the rules of aggregation and consensus measure that are proposed by authors working on social choice in fuzzy framework are examined.

Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration, task 3

Science.gov (United States)

1978-01-01

A structural design study was conducted to assess the relative merits of structural concepts using advanced composite materials for an advanced supersonic aircraft cruising at Mach 2.7. The configuration and structural arrangement developed during Task I and II of the study, was used as the baseline configuration. Allowable stresses and strains were established for boron and advanced graphite fibers based on projected fiber properties available in the next decade. Structural concepts were designed and analyzed using graphite polyimide and boron polyimide, applied to stiffened panels and conventional sandwich panels. The conventional sandwich panels were selected as the structural concept to be used on the wing structure. The upper and lower surface panels of the Task I arrow wing were redesigned using high-strength graphite polyimide sandwich panels over the titanium spars and ribs. The ATLAS computer system was used as the basis for stress analysis and resizing the surface panels using the loads from the Task II study, without adjustment for change in aeroelastic deformation. The flutter analysis indicated a decrease in the flutter speed compared to the baseline titanium wing design. The flutter analysis indicated a decrease in the flutter speed compared to the baseline titanium wing design. The flutter speed was increased to that of the titanium wing, with a weight penalty less than that of the metallic airplane.

Threshold responses of Blackside Dace (Chrosomus cumberlandensis) and Kentucky Arrow Darter (Etheostoma spilotum) to stream conductivity

Science.gov (United States)

Hitt, Nathaniel P.; Floyd, Michael; Compton, Michael; McDonald, Kenneth

2016-01-01

Chrosomus cumberlandensis (Blackside Dace [BSD]) and Etheostoma spilotum (Kentucky Arrow Darter [KAD]) are fish species of conservation concern due to their fragmented distributions, their low population sizes, and threats from anthropogenic stressors in the southeastern United States. We evaluated the relationship between fish abundance and stream conductivity, an index of environmental quality and potential physiological stressor. We modeled occurrence and abundance of KAD in the upper Kentucky River basin (208 samples) and BSD in the upper Cumberland River basin (294 samples) for sites sampled between 2003 and 2013. Segmented regression indicated a conductivity change-point for BSD abundance at 343 μS/cm (95% CI: 123–563 μS/cm) and for KAD abundance at 261 μS/cm (95% CI: 151–370 μS/cm). In both cases, abundances were negligible above estimated conductivity change-points. Post-hoc randomizations accounted for variance in estimated change points due to unequal sample sizes across the conductivity gradients. Boosted regression-tree analysis indicated stronger effects of conductivity than other natural and anthropogenic factors known to influence stream fishes. Boosted regression trees further indicated threshold responses of BSD and KAD occurrence to conductivity gradients in support of segmented regression results. We suggest that the observed conductivity relationship may indicate energetic limitations for insectivorous fishes due to changes in benthic macroinvertebrate community composition.

Justicia epistémica y epistemologías del Sur

Directory of Open Access Journals (Sweden)

Miguel Mandujano Estrada

2017-05-01

Full Text Available Realizaré, en este trabajo, una síntesis de la dimensión epistemológica de la obra de Boaventura de Sousa Santos. A partir de la idea de justicia e injusticia epistémica, reconstruiré la dimensión metodológica de su plataforma crítica, a saber, la ecología de saberes. Intentaré establecer la relación de la injusticia epistémica con el colonialismo y defender la particularidad descolonial de las prácticas inscritas en las epistemologías del Sur y el cosmopolitismo subalterno.

Interacciones sociales y explotación económica

Directory of Open Access Journals (Sweden)

Andrés Montaña

2012-05-01

Full Text Available Planteo aquí un nuevo modelo de interacción social general basado en lasdotaciones de información, heurística y recursos de los agentes de una organización social. A partirde estas dotaciones se puede hacer una representación en un espacio social determinado en el quese desarrollan interacciones sociales. El modelo permite identificar la posición de un agente en elespacio social y hacer comparaciones interpersonales.A partir del modelo de interacción social general, planteo un modelo de explotación económica.Una autoridad desde este modelo de explotación puede establecer áreas de restricción para determinarla explotación económica de los agentes.El cálculo de las dotaciones y las combinaciones de éstas, pueden permitir a una autoridaddeterminar si existe o no explotación de unos agentes por otros, fijar categorías de explotación, eidentificar áreas de atención prioritarias. El modelo se podría constituir en una herramienta másapropiada para la identificación de la condición laboral o económica de los niños y niñas.

CARACTERIZACIÓN QUÍMICA Y CLASIFICACIÓN TAXONÓMICA DE ALGUNOS SUELOS CULTIVADOS CON BANANO EN LAS LLANURAS ALUVIALES DEL CARIBE DE COSTA RICA

Directory of Open Access Journals (Sweden)

Fulvio Arias

2010-01-01

Full Text Available Se realizó la caracterización morfológica, química y la clasificación taxonómica de algunos suelos cultivados con banano en las 11 cuencas hidrográficas que confluyen en las llanuras aluviales de la Vertiente Caribe de Costa Rica. Se identificaron 2 sectores con suelos que tienen propiedades morfológicas, químicas, y taxonómicas diferentes. En una zona, se encontraron principalmente Inceptisoles formados a partir de materiales fluvio-volcánicos con propiedades ándicas (Andic Eutrudepts, Aquandic Endoaquepts, Inceptisoles dístricos (Fluventic Dystrudepts y Andisoles (Typic Hapludands; caracterizados por presentar la mayoría buen drenaje, texturas medias (franco arenosa, franca, franca limosa, una suma de bases entre 10 y 19 cmol.l–1, una CIC entre 13 y 28 cmol.l–1 y carga permanente en la arcillas. En la otra zona, se encontraron principalmente Inceptisoles formados a partir de aluviones de origen sedimentario depositados por inundaciones frecuentes (Fluventic Endoaquepts, Dystric Fluventic Eutrudepts, Fluvaquentic Eutrudepts, Fluvaquentic Endoaquepts, con una suma de bases entre 18 y 46 cmol.l–1, una CIC entre 19 y 46 cmol.l–1, sin propiedades ándicas, texturas finas y moderadamente finas (franco arcillosa, franco arcillosa limosa, arcillosa, arcillosa limosa y con problemas de drenajes en algunos casos (Endoaquepts, Epiaquepts, Fluvaquentic. Geográficamente, estas zonas fueron separadas por la subcuenca formada por los ríos Vueltas-Silencio-Parismina, de forma que hacia el noroeste se encuentran suelos con influencia volcánica y fertilidad media, y hacia el sureste suelos sin influencia volcánica y de fertilidad alta.

La flexibilitat en els àcids nucleics: Un estudi de dinàmica molecular

OpenAIRE

Noy Freixa, Agnès

2008-01-01

[cat] L'estat de l'art de les simulacions de dinàmica molecular és utilitzat per estudiar l'estructura, dinàmica, propietats d'interacció molecular i flexibilitat dels dúplexs d'ADN i ARN en solució acuosa. Les nostres simulacions suggereixen que el concepte de flexibilitat, rigidesa i deformabilitat són molt més complexes del que habitualment es creu, i que per tant no és sempre veritat que l'ADN sigui més flexible que l'ARN. La dinàmica molecular és a més utilitzada per investigar les prop...

Flexibilitat en els àcids nucleics: Un estudi de dinàmica molecular, La

OpenAIRE

Noy Freixa, Agnès

2008-01-01

L'estat de l'art de les simulacions de dinàmica molecular és utilitzat per estudiar l'estructura, dinàmica, propietats d'interacció molecular i flexibilitat dels dúplexs d'ADN i ARN en solució acuosa. Les nostres simulacions suggereixen que el concepte de flexibilitat, rigidesa i deformabilitat són molt més complexes del que habitualment es creu, i que per tant no és sempre veritat que l'ADN sigui més flexible que l'ARN.La dinàmica molecular és a més utilitzada per investigar les propietats d...

ANÁLISE DINÂMICA DE ESTRUTURAS DE AÇO SUPORTES DE MÁQUINAS ROTATIVAS

OpenAIRE

FERRO, R. M.

2014-01-01

Uma análise dinâmica adequada é necessária para verificação de estruturas suportes de equipamentos mecânicos visando assegurar não somente o conforto humano dos usuários como também boas condições para o funcionamento dos equipamentos da estrutura. Em recentes estudos de dinâmica estrutural e dinâmica de equipamentos, verifica-se a dificuldade de realizar modelos reais de estruturas suportes de máquinas rotativas. Considerando que as duas áreas têm o estudo comum na análise das vibrações prod...

Box-and-arrow explanations need not be more abstract than neuroscientific mechanism descriptions.

Science.gov (United States)

Datteri, Edoardo; Laudisa, Federico

2014-01-01

The nature of the relationship between box-and-arrow (BA) explanations and neuroscientific mechanism descriptions (NMDs) is a key foundational issue for cognitive science. In this article we attempt to identify the nature of the constraints imposed by BA explanations on the formulation of NMDs. On the basis of a case study about motor control, we argue that BA explanations and NMDs both identify regularities that hold in the system, and that these regularities place constraints on the formulation of NMDs from BA analyses, and vice versa. The regularities identified in the two kinds of explanation play a crucial role in reasoning about the relationship between them, and in justifying the use of neuroscientific experimental techniques for the empirical testing of BA analyses of behavior. In addition, we make claims concerning the similarities and differences between BA analyses and NMDs. First, we argue that both types of explanation describe mechanisms. Second, we propose that they differ in terms of the theoretical vocabulary used to denote the entities and properties involved in the mechanism and engaging in regular, mutual interactions. On the contrary, the notion of abstractness, defined as omission of detail, does not help to distinguish BA analyses from NMDs: there is a sense in which BA analyses are more detailed than NMDs. In relation to this, we also focus on the nature of the extra detail included in NMDs and missing from BA analyses, arguing that such detail does not always concern how the system works. Finally, we propose reasons for doubting that BA analyses, unlike NMDs, may be considered "mechanism sketches." We have developed these views by critically analyzing recent claims in the philosophical literature regarding the foundations of cognitive science.

Box-and-arrow explanations need not be more abstract than neuroscientific mechanism descriptions

Directory of Open Access Journals (Sweden)

Edoardo eDatteri

2014-05-01

Full Text Available The nature of the relationship between box-and-arrow (BA explanations and neuroscientific mechanism descriptions (NMDs is a key foundational issue for cognitive science. In this article we attempt to identify the nature of the constraints imposed by BA explanations on the formulation of NMDs. On the basis of a case study about motor control, we argue that BA explanations and NMDs both identify regularities that hold in the system, and that these regularities place constraints on the formulation of NMDs from BA analyses, and vice versa. The regularities identified in the two kinds of explanation play a crucial role in reasoning about the relationship between them, and in justifying the use of neuroscientific experimental techniques for the empirical testing of BA analyses of behavior. In addition, we make claims concerning the similarities and differences between BA analyses and NMDs. First, we argue that both types of explanation describe mechanisms. Second, we propose that they differ in terms of the theoretical vocabulary used to denote the entities and properties involved in the mechanism and engaging in regular, mutual interactions. On the contrary, the notion of abstractness, defined as omission of detail, does not help to distinguish BA analyses from NMDs: there is a sense in which BA analyses are more detailed than NMDs. In relation to this, we also focus on the nature of the extra detail included in NMDs and missing from BA analyses, arguing that such detail does not always concern how the system works. Finally, we propose reasons for doubting that BA analyses, unlike NMDs, may be considered mechanism sketches. We have developed these views by critically analyzing recent claims in the philosophical literature regarding the foundations of cognitive science.

Zirconia toughened mica glass ceramics for dental restorations.

Science.gov (United States)

Gali, Sivaranjani; K, Ravikumar; Murthy, B V S; Basu, Bikramjit

2018-03-01

The objective of the present study is to understand the role of yttria stabilized zirconia (YSZ) in achieving the desired spectrum of clinically relevant mechanical properties (hardness, elastic modulus, fracture toughness and brittleness index) and chemical solubility of mica glass ceramics. The glass-zirconia mixtures with varying amounts of YSZ (0, 5, 10, 15 and 20wt.%) were ball milled, compacted and sintered to obtain pellets of glass ceramic-YSZ composites. Phase analysis was carried out using X-ray diffraction and microstructural characterization with SEM revealed the crystal morphology of the composites. Mechanical properties such as Vickers hardness, elastic modulus, indentation fracture toughness and chemical solubility were assessed. Phase analysis of sintered pellets of glass ceramic-YSZ composites revealed the characteristic peaks of fluorophlogopite (FPP) and tetragonal zirconia. Microstructural investigation showed plate and lath-like interlocking mica crystals with embedded zirconia. Vickers hardness of 9.2GPa, elastic modulus of 125GPa, indentation toughness of 3.6MPa·m 1/2 , and chemical solubility of 30μg/cm 2 (well below the permissible limit) were recorded with mica glass ceramics containing 20wt.% YSZ. An increase in hardness and toughness of the glass ceramic-YSZ composites with no compromise on their brittleness index and chemical solubility has been observed. Such spectrum of properties can be utilised for developing a machinable ceramic for low stress bearing inlays, onlays and veneers. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Estudos ecológicos preliminares e caracterização química dos Cnidaria da costa noroeste portuguesa

OpenAIRE

Gadelha, Juliana Rodrigues

2007-01-01

O levantamento de recursos em espécies marinhas em Portugal ainda é incipiente, considerando que este domínio de investigação tem sido amplamente desenvolvido noutros pontos do globo, pescas, química, bioquímica e farmacologia de organismos marinhos, de modo a obter informações sobre a química de produtos naturais e ecologia química de organismos marinhos derivadas destes organismos. São de realçar a importância das defesas químicas para as relações ecológicas de predação, comp...

RF Characteristics of Mica-Z Wireless Sensor Network Motes

National Research Council Canada - National Science Library

Koh, Swee J

2006-01-01

... network characteristics. Link-break and re-association distances with their corresponding RF power measurements were recorded to determine the Mica-Z s range characteristics under these different operating environments...

Deserción universitaria y alfabetización académica

OpenAIRE

Giohanny Olave-Arias; llene Rojas-García; Mireya Cisneros-Estupiñán

2013-01-01

El artículo pone en relación la deserción universitaria con la alfabetización académica, entendida como el nivel de desarrollo de la lectura y la escritura. El desarrollo del artículo consta de tres momentos: contextualización del problema de la deserción universitaria en Colombia; prácticas de lectura y escritura que generan dificultades de aprendizaje; importancia de la alfabetización académica para mejorar las habilidades lectoras de los estudiantes.

Topographic characterization of the self-assembled nanostructures of chitosan on mica surface by atomic force microscopy

International Nuclear Information System (INIS)

Wang, Li; Wu, Jiafeng; Guo, Yan; Gong, Coucong; Song, Yonghai

2015-01-01

Graphical abstract: - Highlights: • Nanocomposites of chitosan film were prepared by simple self-assembly from solvent media. • Chitosan molecules assembled on mica surface of nanoparticles, fibril and membrane with varied chitosan concentration. • Chitosan molecules assembled with different nanostructure under varied pH. • The optimum drying temperature for forming chitosan membrane is about 65 °C. - Abstract: In this work, the self-assembled nanostructures of chitosan on mica surface formed from various solvents were investigated by using atomic force microscopy. The effects of various factors on the self-assembled nanostructures of chitosan on mica surface, including solvents, the concentration of chitosan, the pH of solution and the drying temperature, were explored in detail. Our experimental data resulted in the conclusion that chitosan molecules could self-assemble on mica surface to form various nanostructures such as nanoparticles, fibril and film. Nanoparticles were always formed on mica surface from CCl_4, C_6H_6, CH_2Cl_2 solution, fibril preferred to form on mica surface from CH_3CH_2OH and CH_3OH solution and the optimal solvent to form film was found to be CH_3CN. Low concentration, pH and temperature were helpful for the formation of nanoparticles, medium concentration, pH and temperature resulted in fibril and high concentration, pH and temperature were often beneficial to forming chitosan films. The study of self-assembled nanostructures of chitosan on mica surface would provide new insight into the development of chitosan-based load-bearing materials.

Tunnetades kuumust / Emma Duncan

Index Scriptorium Estoniae

Duncan, Emma

2006-01-01

Autor prognoosib, et juba lähiajal hakkavad Valitsustevahelise Kliimamuutuste Ekspertrühma (IPCC- Intergovernmental Panel on Climate Change) aruanded mõjutama poliitikakujundamist maailmas. Diagramm: Elavhõbedasammas kerkib

Algunas características económicas del mantenimiento no correctivo del software a medida.

OpenAIRE

Torralba Martínez, José María; Rodenes Adam, Manuel

2001-01-01

Se presentan algunas características económicas del servicio de mantenimiento del software, relativas pricipalmente al área comercial: mercado, producto, precio y clientización, apuntando la importancia económica que tiene tanto para

Some mica-vermiculite alterations-relation to the exchange capacity

International Nuclear Information System (INIS)

Misak, N.Z.; Abdel-Gawad, A.S.; Maghrawy, H.B.; Shafik, A.; Sayyah, T.

1983-01-01

The effect of treatment of six Indian mica-vermiculite minerals with sodium cobaltinitrite (I) and NaCl+H 2 O 2 (II) with the aim of producing more vermiculite in the structure and thus a higher sorption capacity, was studied. The changes occuring in the minerals were followed by X-ray, TG, DTA, and chemical analyses. The measured Sr 2+ and Co 2+ capacities were in basic agreement with the detected changes that revealed generally a minor alteration due to treatment I and a considerable one but to treatment II. Treatment II increased tremendously the capacity of the main-mica minerals, having a very small capacity in the natural form, and made them suitable for use as potential ion exchangers

Particle size and kind of mica in synthesis of nontoxic bronze and gold pearlescent pigments based on nanoencapsulated hematite

Directory of Open Access Journals (Sweden)

Maryam Hosseini-Zori

2015-12-01

Full Text Available Nano-encapsulated iron oxide in Zirconium oxide-coated mica pigments are thermally stable,innocuous to human health, non-combustible, and they do not conduct electricity. They could beapplied in several industries such as thermoplastics, cosmetics, food packaging, children toys, paints,automobiles coating, security purposes, and banknotes. Nowadays, they are highly desirable inceramic decoration. In the present study, intensively dark gold to bronze colored mica clay pigments,which were based on mica flakes covered with a layer of nano-iron oxide-Zirconium oxide particles,were prepared by homogeneous precipitation of iron nitrate and Zirconium chloride ammonia in thepresence of mica flakes in two kinds of ore clay-based phlogopite and muscovite minerals. The finalcolor was obtained by thermal annealing of precipitates at a temperature of 800◦C. The pigments werecharacterized by X-Ray Diffraction, Particle size analysis, Scanning electron microscopy,Transmission electron microscopy, X-Ray fluorescence, and Simultaneous thermal analysis. Resultsindicate that nano-encapsulated iron oxide in zirconia particles have been formed on mica flakes andkinds of clay-mica can be related to obtained shade from dark gold to bronze pearl. Higher particlesize of mica flakes about phlogopite type of mica introduced pearl effects with higher L* changes indifferent angles. Muscovite performed higher hue and better pearl effect than phlogopite.

Diagnóstico y tendencias económicas del Corredor Tijuana-Rosarito-Ensenada

Directory of Open Access Journals (Sweden)

Wilfrido Ruiz Ochoa

2015-01-01

Full Text Available En este artículo se proponen estrategias que pudieran implementarse para romper con un escenario económico inercial adverso que, hipotéticamente, pudiera restarle viabilidad económica a futuro al Corredor Costero Tijuana- Rosarito-Ensenada. Esto, a partir de un diagnóstico económico sustentado en índices multidimensionales, en el que se aporta información censal sobre el perfil sectorial y espacial del corredor, así como de sus tendencias de crecimiento para 2030. Sobre esta base se elaboran propuestas para afrontar la desaceleración económica reciente de la zona, mediante la identificación de sus vocaciones económicas y de algunos proyectos estratégicos.

El derecho de propiedad privada y libertad económica

Directory of Open Access Journals (Sweden)

Santiago M. Castro Videla

2014-03-01

Full Text Available Este artículo ofrece diversos elementos legales, filosóficos y económicos para una teoría general del derecho de propiedad y libertad económica, que permita explicar por qué es un derecho fundamental. En primer lugar, plantea una visión unificada del derecho de propiedad privada y libertad económica, el que debe distinguirse analíticamente de los distintos derechos de propiedad susceptibles de reglamentación y expropiación estatal. En segundo lugar, explica, desde la teoría tomista del derecho natural, en qué sentido este derecho es un derecho natural secundario. En tercer lugar, señala, desde la teoría austríaca del proceso de mercado, cómo la protección del derecho de propiedad privada y libertad económica da lugar a un proceso virtuoso que genera mayor desarrollo, reducción de la pobreza y paz social. Y finalmente, explica también cómo la violación de dicho derecho genera los efectos contrarios: subdesarrollo, pobreza y conflicto social.

A pura química : Curso a distancia para alumnos e Ingeniería

OpenAIRE

Tocci, Ana María; Fertitta, A. E.; Visintin, Arnaldo

2015-01-01

La Facultad de Ingeniería de la ciudad de La Plata (UNLP) requiere para permitir el ingreso a la misma aprobar un examen de matemáticas, el cual se rinde en el mes de diciembre, o aprobar un curso nivelatorio de la misma materia durante el mes de febrero. En ese curso no está contemplada la materia Química. Los docentes de la cátedra de Química General (materia del primer cuatrimestre de primer año) para Ingeniería Química y Materiales, encontramos un vacío en lo que respecta a conocimientos ...

Deserción universitaria y alfabetización académica

Directory of Open Access Journals (Sweden)

Giohanny Olave-Arias

2013-12-01

Full Text Available El artículo pone en relación la deserción universitaria con la alfabetización académica, entendida como el nivel de desarrollo de la lectura y la escritura. El desarrollo del artículo consta de tres momentos: contextualización del problema de la deserción universitaria en Colombia; prácticas de lectura y escritura que generan dificultades de aprendizaje; importancia de la alfabetización académica para mejorar las habilidades lectoras de los estudiantes.

Mutaciones dinámicas

Directory of Open Access Journals (Sweden)

Cesar A. Parra

1994-10-01

Full Text Available EI descubrimiento de repeticiones amplificadas de trinucleótidos variables en número, en pacientes con distrofia miotónica, síndrome de X-frágil, corea de Huntington y enfermedad de Kennedy, al igual que alteraciones en dinucleótidos del DNA microsatélite en pacientes con carcinoma proximal de colon, ha dado origen al concepto de mutaciones dinámicas. Esto representa una nueva avenida en teoría genética contemporánea que explica fenómenos como lo anticipación y la paradoja de Sherman que se salen del patrón mendeliano clásico.

Estrategias sociales y económicas de los nuevos jubilados.

Directory of Open Access Journals (Sweden)

Antonio Trinidad Requena

2006-01-01

Full Text Available Desde mediados de la década de los ochenta, las personas mayores han ido adquiriendo una especial relevancia y un mayor protagonismo en las sociedades modernas. El jubilado de hoy no es el jubilado del pasado, siendo necesario distinguir entre el jubilado tradicional y el nuevo jubilado, que será el jubilado del futuro. Este nuevo jubilado es el objetivo de este trabajo, centrado en conocer las estrategias sociales y económicas que utilizan para adaptarse a la nueva situación. Para conocer las estrategias sociales y económicas del nuevo jubilado nos centramos en el análisis de sus discursos.

Nucleation and crystallization behaviors of nano-crystalline lithium–mica glass–ceramic prepared via sol–gel method

Energy Technology Data Exchange (ETDEWEB)

Tohidifar, M.R. [Department of Materials Science and Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Alizadeh, P., E-mail: p-alizadeh@modares.ac.ir [Department of Materials Science and Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Riello, P. [Department of Molecular Sciences and Nanosystems, University of Ca’Foscari, Venice (Italy)

2012-06-15

Graphical abstract: The effects of nucleation and crystallization treatments on nano-crystalline lithium–mica glass–ceramic, synthesized by sol–gel technique, were investigated. It was found that MgF{sub 2} crystals act as nuclei centers for the mica crystallization so that a large quantity of mica crystallites was obtained following nucleation process. The crystallization activation energy for both the un-nucleated and nucleated samples was measured as 400.2 and 229.6 kJ mol{sup −1}, respectively. The calculated Avrami exponents demonstrated that the growth mechanism of mica crystallites changes from the needle-like to three-dimensional growth with applying the appropriate nucleation treatment ▪. Highlights: ► Crystallization temperature shifts to 625 from 680 °C following nucleation process. ► Activation energy of crystallization for the nucleated specimen is 229.6 kJ mol{sup −1}. ► Crystallization activation energy for the un-nucleated specimen is 400.2 kJ mol{sup −1}. ► Needle-like growth is predominant growth mechanism for un-nucleated sample. ► Three-dimensional growth is predominant growth mechanism for nucleated sample. -- Abstract: The paper investigates the effects of nucleation and crystallization treatments on nano-crystalline lithium–mica glass–ceramics, taking the composition LiMg{sub 3}AlSi{sub 3(1+x)}O{sub 10+6x}F{sub 2} (x = 0.5) and 8 mass% MgF{sub 2} synthesized by sol–gel technique. Here, X-ray diffraction, thermal analysis and transmission electron microscopy were used to assess the structural evolutions of as-synthesized nano-crystalline lithium–mica glass–ceramics. It was found that MgF{sub 2} crystals perform as nuclei centers for the mica crystallization hence; a large quantity of mica crystallites obtained following the nucleation process at 400 °C for 12 h. For both the un-nucleated and nucleated samples, the crystallization activation energy was measured as 400.2 and 229.6 kJ mol{sup −1

Angeitis necrotizante sistémica no supurativa

Directory of Open Access Journals (Sweden)

Gabriel Toro G.

1972-04-01

Full Text Available 1. Se estudian 3 casos de angeítis necrotizante sistémica no supurativa: un hombre de 36 y una mujer de 58 años con granulomatosis de Wegener y un hombre de 30 años con granulomatosis alérgica del tipo descrito por Churg y Strauss. 2. Se prefiere el hombre de angeítis necrotizante sistémica no supurativa como lo ha hecho Paronetto cuando trata este capítulo desde el punto de vista inmunopatológico. 3. Consideran los autores que la lesión renal es la periglomerulitis granulomatosa parahiliar y que su presencia ya en la biopsia tiene gran valor diagnóstico. 4. Se subraya que el cuadro clínico, la marcada eosinofilia tisular y la presencia de imágenes micromultinodulares en el ganglio linfático, apoyan sólidamente un diagnóstico de granulomatosis alérgica de la forma descrita por Churg y Strauss. 5. Se hace una amplia revisión bibliográfica.

Habilidades académicas en estudiantes de nuevo ingreso a la Universidad del Zulia

Directory of Open Access Journals (Sweden)

Mariana Fernández Reina

2015-01-01

Full Text Available Al inicio de su carrera universitaria algunos jóvenes demuestran no poseer las habilidades académicas necesarias para alcanzar la culminación de sus estudios. Esta investigación se enfoca en diagnosticar las habilidades académicas de los estudiantes cuando ingresan a la universidad. Se plantea una investigación descriptiva, con un diseño transeccional, univariable, de campo, no experimental. La población de estudio estuvo conformada por 940 estudiantes que ingresaron al Núcleo Costa Oriental del Lago de la Universidad del Zulia en las carreras de Ingeniería, Ciencias Económicas y Sociales, y Educación, para el primer período de 2012. La muestra seleccionada fue no probabilística, conformada por 179 estudiantes. El instrumento empleado para la recolección de datos fue la escala de habilidades académicas en estudiantes universitarios, compuesta por 40 reactivos, tipo Likert, la cual alcanzó una confiabilidad alfa de Cronbach de 0,86. Según los resultados los estudiantes de nuevo ingreso poseen un nivel bajo de habilidades académicas (organización; empleo de técnicas; motivación, lo cual no les permite abordar con éxito los retos de la vida universitaria. Se sugiere reforzar las mismas a través de la práctica.

Visualisation Ability of Senior High School Students with Using GeoGebra and Transparent Mica

International Nuclear Information System (INIS)

Thohirudin, M; Maryati, TK; Dwirahayu, G

2017-01-01

Visualisation ability is an ability to process, inform, and transform object which suitable for geometry topic in math. This research aims to describe the influence of using software GeoGebra and transparent mica for student’s visualisation ability. GeoGebra is shortness of geometry and algebra. GeoGebra is an open source program that is created for math. Transparent mica is a tool that is created by the author to transform a geometry object. This research is a quantitative experiment model. The subject of this research were students in grade XII of science program in Annajah Senior High School Rumpin with two classes which one as an experiment class (science one) and another one as a control class (science two). Experiment class use GeoGebra and transparent mica in the study, and control class use powerpoint in the study. Data of student’s visualisation ability is collected from posttest with visual questions which are gifted at the end of the research to both classes with topic “transformation geometry”. This research resulted that studying with GeoGebra and transparent mica had a better influence than studying with powerpoint to student’s visualisation ability. The time of study in class and the habit of the students to use software and tool affected the result of research. Although, GeoGebra and transparent mica can give help to students in transformation geometry topic. (paper)

La caja negra de la dinámica empresarial

Directory of Open Access Journals (Sweden)

María Callejón

2009-01-01

Full Text Available Este artículo intenta aportar conocimientos sobre la contribución a la política industrial de la investigación en dinámica empresarial. Los programas de fomento a la creación de empresas se han generalizado aunque se desconoce cuál es el ritmo óptimo de creación y destrucción empresarial. El análisis económico destaca la heterogeneidad empresarial como característica dominante en la dinámica industrial. La profundización en el conocimiento de los tipos de emprendedores, su comportamiento, y su contribución diferencial a la innovación y el crecimiento permitirá ver en la "caja negra" y diseñar programas públicos adecuados. El análisis empírico realizado encuentra que la naturaleza económica del autoempleo es muy diferente de las empresas con empleados. Los programas públicos deberían priorizar entrantes con capacidad de sobrevivir y no maximizar la entrada indiscriminadamente. La supervivencia de las nuevas empresas se encuentra positivamente relacionada con su tamaño al nacer. La innovación y la inversión mejoran la supervivencia de las nuevas empresas manufactureras. La inversión en I+D aumenta el riesgo de las nuevas empresas, aunque mejore la competitividad de las empresas establecidas.

La caja negra de la dinámica empresarial

Directory of Open Access Journals (Sweden)

María Callejón

2009-10-01

Full Text Available Este artículo intenta aportar conocimientos sobre la contribución a la política industrial de la investigación en dinámica empresarial. Los programas de fomento a la creación de empresas se han generalizado aunque se desconoce cuál es el ritmo óptimo de creación y destrucción empresarial. El análisis económico destaca la heterogeneidad empresarial como característica dominante en la dinámica industrial. La profundización en el conocimiento de los tipos de emprendedores, su comportamiento, y su contribución diferencial a la innovación y el crecimiento permitirá ver en la “caja negra” y diseñar programas públicos adecuados. El análisis empírico realizado encuentra que la naturaleza económica del autoempleo es muy diferente de las empresas con empleados. Los programas públicos deberían priorizar entrantes con capacidad de sobrevivir y no maximizar la entrada indiscriminadamente. La supervivencia de las nuevas empresas se encuentra positivamente relacionada con su tamaño al nacer. La innovación y la inversión mejoran la supervivencia de las nuevas empresas manufactureras. La inversión en I+D aumenta el riesgo de las nuevas empresas, aunque mejore la competitividad de las empresas establecidas.

MICA: desktop software for comprehensive searching of DNA databases

Directory of Open Access Journals (Sweden)

Glick Benjamin S

2006-10-01

Full Text Available Abstract Background Molecular biologists work with DNA databases that often include entire genomes. A common requirement is to search a DNA database to find exact matches for a nondegenerate or partially degenerate query. The software programs available for such purposes are normally designed to run on remote servers, but an appealing alternative is to work with DNA databases stored on local computers. We describe a desktop software program termed MICA (K-Mer Indexing with Compact Arrays that allows large DNA databases to be searched efficiently using very little memory. Results MICA rapidly indexes a DNA database. On a Macintosh G5 computer, the complete human genome could be indexed in about 5 minutes. The indexing algorithm recognizes all 15 characters of the DNA alphabet and fully captures the information in any DNA sequence, yet for a typical sequence of length L, the index occupies only about 2L bytes. The index can be searched to return a complete list of exact matches for a nondegenerate or partially degenerate query of any length. A typical search of a long DNA sequence involves reading only a small fraction of the index into memory. As a result, searches are fast even when the available RAM is limited. Conclusion MICA is suitable as a search engine for desktop DNA analysis software.

Compatibilidad entre nueve cepas de Biomphalaria glabrata de áreas endémicas y no endémicas y una cepa de Schistosoma mansoni venezolanas

OpenAIRE

Pino,Luz A.; Matinella,Liboria; Morales C.,Gustavo

1999-01-01

Se infectaron experimentalmente 9 lotes de 32 caracoles B. glabrata (de 5 a 7mm de diámetro) con miracidios de la cepa C5 de Schistosoma mansoni a razón de 5 miracidios por caracol, pertenecientes a las siguientes cepas: En el área endémica de transmisión de Esquistosomiasis mansoni a) Sector Puerta Negra, Lago Valencia, b) Cagua c) Ingenio Bolívar (Estado Aragua) d) Mariara e) Caserío El 25 f) Güigüe (Estado Carabobo). Fuera del área endémica de transmisión g) Anzoátegui (Estado Lara), h) Ch...

Mejora en la motivación por la Lectura Académica: la mirada de estudiantes motivados

Directory of Open Access Journals (Sweden)

Carla Muñoz

2016-01-01

Full Text Available Dada la importancia de la lectura académica en la formación universitaria y que uno de los factores gravitantes en este tipo de tarea son los aspectos motivacionales, el presente trabajo tuvo como objetivo identificar los elementos, que según los propios protagonistas explicarían el incremento de su motivación por la lectura de textos académicos. El estudio de carácter mixto se realizó en dos fases. En una primera fase fueron identificados a partir de una muestra amplia (n=1205 estudiantes con alta motivación por la lectura académica y que hubiesen experimentado un cambio motivacional positivo (n=10. En una segunda fase, estos casos fueron sujetos de entrevistas en profundidad y el análisis de estas entrevistas se recogen en este artículo. Los resultados muestran como causas de la mejora de la motivación por la lectura académica, dinámicas vinculadas con el desafío, el ingreso a la lógica universitaria (desescolarización y las proyecciones académico/profesionales de estos estudiantes; procesos que se encuentran vinculados a los primeros años de formación, favorecidos por docentes que promueven una dinámica académica en la formación. Se discuten finalmente las implicaciones de estas dinámicas para la formación universitaria.

Electrohidrodinámica de cristales líquidos nemáticos

Directory of Open Access Journals (Sweden)

Rosalío F. Rodríguez

2001-01-01

Full Text Available Se presenta un formalismo analítico que permite describir una amplia variedad de fenómenos ópticos no lineales que ocurren cuando una onda electromagnética se propaga en un cristal líquido. A partir de propiedades termodinámicas y de simetría, primero se construye un conjunto cerrado de ecuaciones hidrodinámicas que proporcionan una descripción completa de la dinámica de un nemático de bajo peso molecular en ausencia de campos externos. Posteriormente, se incluye la presencia de un campo electromagnético externo que se propaga en el fluido. Se discute el carácter no lineal y acoplado de las ecuaciones y, para resolverlas, se propone un método iterativo de aproximaciones sistemáticas en términos de potencias de parámetros con una interpretación física precisa. Se concluye discutiendo las ventajas y limitaciones del punto de vista adoptado en este trabajo..

A dinâmica do crédito no Brasil entre 1990-2006.

Directory of Open Access Journals (Sweden)

Juliano Morais Galle

2008-05-01

Full Text Available Este artigo aborda, dentro de um contexto de globalização financeira, a dinâmica e o desenvolvimento recente do mercado financeiro e de crédito no Brasil. É mostrado que a dinâmica do crédito se caracterizou por três fases distintas entre 1990 e 2003. Além disso, discute-se que, após a implantação do Plano Real, houve um grande esforço por parte do governo brasileiro em reestruturar e reforçar o Sistema Financeiro Nacional, e que a conjuntura econômica observada atualmente no Brasil é bem mais favorável ao crescimento da relação crédito/PIB que no início da década de 2000.

CARACTERIZACIÓN MORFOLÓGICA Y ANATÓMICA DEL GÉNERO STEREOCAULON HOFFMANN (ASCOMYCETES-LIQUENIZADOS EN COLOMBIA

Directory of Open Access Journals (Sweden)

ANGÉLICA RINCÓN-ESPITIA

2013-12-01

Full Text Available El género Stereocaulon presenta una gran plasticidad en sus estructuras morfológicas y anatómicas, que de no ser reconocidas se puede recaer en errores taxonómicos a nivel intraespecífico. Por esta razón, se presenta una diferenciación morfoanatómica de los caracteres diagnósticos: los filocladios, los cefalodios y los soredios para facilitar el proceso de identificación taxonómica. En esta contribución se reconocen 19 especies junto con cinco variedades de Stereocaulon para Colombia, se amplían los datos de distribución geográfica y se incluye una clave taxonómica para la identificación de las especies en el país.

Sobre lo económico de la Historia Económica: Dos concepciones contrapuestas

Directory of Open Access Journals (Sweden)

Nicolás Mohaded

2013-05-01

Full Text Available Las tendencias a incrementar las contribuciones interdisciplinarias no son ajenas a la ciencia económica. Desde distintas vertientes teóricas gran cantidad de autores han intentado lograr explicaciones más comprehensivas sobre la realidad social a partir de la confluencia de disciplinas. El caso de la historia económica como conjunción de la economía y la historia puede dar cuenta de ello. Sin embargo, no existe una única manera de enfocar el análisis en esta dirección. En este sentido, este trabajo presenta dos corrientes teóricas distintas en relación a la historia económica. Por un lado el enfoque neo-institucionalista de North y Thomas y por otro el enfoque marxista de Dobb. Se plantean las distintas perspectivas teóricas que cada uno de estos dos aparatos analíticos proponen, particular-mente en lo referido a lo económico de la historia económica, y sus implicancias sobre el análisis de la realidad social.

Planificación de trayectorias para un robot tipo con restricciones dinámicas

Directory of Open Access Journals (Sweden)

Leonardo Solaque Guzmán

2008-01-01

Full Text Available Este documento presenta una aproximación a la planificación de caminos óptimos para un sistema con restricciones dinámicas y desplazándose dentro de un espacio libre de obstáculos. Se considera el modelo dinámico del dirigible y un análisis para el planteamiento de modelos simplificados o comúnmente conocidos como modelos de control. Se propone una planificación de la trayectoria desde el punto de vista de la teoría óptima utilizando un modelo de la dinámica de un robot móvil (que se desplaza a velocidad constante y en avance, es decir con restricciones dinámicas como punto de partida para la primera aproximación a los caminos óptimos. Para el suavizado de las trayectorias del dirigible se proponen dos modelos con relajación en la dinámica de la variable de control y finalmente se presenta una simulación de la comparación de los diferentes resultados.

DINÂMICA ECONÔMICA E REDE URBANA CEARENSE NO INÍCIO DO SÉCULO XXI

Directory of Open Access Journals (Sweden)

Fernando Cezar de Macedo

2012-03-01

Full Text Available Este artigo discute a dinâmica econômica e a evolução da rede urbana do Ceará nesta primeira década do século XXI. Além das heranças seculares, toma como elemento decisivo na estruturação do espaço cearense as diversas políticas implementadas pelos governos estaduais que articularam a economia cearense aos movimentos das economias brasileira e internacional, influenciando sua organização espacial. Mostra que foi no período colonial que a capital cearense tornou-se principal centro urbano do estado graças à centralização dos excedentes das atividades sertanejas sustentadas no binômio pecuária-algodão. Posteriormente, apresenta as transformações verificadas na fase de integração do mercado nacional, quando se concentraram os principais investimentos na cidade de Fortaleza. Dada essa grande concentração, observam-se esforços de descentralização da atividade produtiva, a partir de uma ação deliberada do governo do estado, através dos instrumentos da guerra fiscal que atraíram para o interior importantes investimentos, sem, contudo, reduzir as disparidades intraestaduais ainda fortemente marcadas pelo predomínio metropolitano. Não obstante, surgem focos dinâmicos na economia cearense, contribuindo para uma maior diferenciação do interior do estado.

A crise econômica de 2014/2017

Directory of Open Access Journals (Sweden)

Fernando de Holanda Barbosa Filho

Full Text Available Resumo Este artigo mostra que a crise de 2014/2017 é fruto de uma combinação de choques de oferta e demanda resultado de erros de política econômica. Esses choques produziram uma redução da capacidade de crescimento da economia brasileira e risco de insolvência das finanças públicas. A solução da crise fiscal, através da PEC do teto dos gastos, fará que o país retome o crescimento econômico a partir de 2017, utilizando a capacidade ociosa da economia. No entanto, a taxa de crescimento do produto potencial não recuperará o ritmo anterior devido aos efeitos duradouros das políticas da Nova Matriz Econômica (NME que reduziram o produto potencial nacional. Recomenda-se, portanto, a adoção de políticas que induzam uma recuperação da produtividade da economia brasileira.

Introducción a la Química Orgánica

OpenAIRE

Autino, Juan Carlos; Romanelli, Gustavo Pablo; Ruiz, Diego Manuel

2013-01-01

Esta obra ha sido concebida atendiendo a las características del Curso de Química Orgánica que ofrecemos en la Facultad de Ciencias Agrarias y Forestales de la Universidad Nacional de La Plata a nuestros alumnos del primer año de las Carreras de Ingeniería Agronómica e Ingeniería Forestal, así como del segundo año de la Licenciatura en Biología. En la misma incorporamos elementos didácticos que hemos introducido y mejorado gradualmente durante varios años, logrando un cierto grado de original...

Avaliação física, química e fitoquímica de frutos de Physalis, ao longo do período de colheita

Directory of Open Access Journals (Sweden)

Cláudia Simone Madruga Lima

2012-12-01

Full Text Available Physalis peruviana L. é uma espécie que vem sendo incorporada em plantios de pequenas frutas. Esta frutífera é tratada como anual, e o principal método de propagação é por sementes. Seu cultivo apresenta uma dinâmica de colheita diferenciada, com duração do período de colheita superior a três meses. Acredita-se que, devido ao extenso período de colheita, associado a diferentes épocas de semeadura, irão ocorrer variações nas características dos frutos. O objetivo deste trabalho foi avaliar as características físicas, químicas e fitoquímicas de frutos de Physalis peruviana ao longo do período de colheita, em função de duas épocas de plantio. O experimento foi realizado no período de 2007/2008. A semeadura foi realizada em duas épocas (04-09-2007 e 26-11-2007, e o transplante foi realizado quando as plantas estavam no estádio de duas folhas verdadeiras. Os frutos foram colhidos aos 120; 150; 180; 210 e 240 dias após o transplante e avaliados quanto à massa total e a coloração da epiderme, assim como quanto aos seus teores de sólidos solúveis (SS, acidez titulável (AT, fenóis e de carotenoides totais, razão SS/AT e atividade antioxidante. Os frutos de Physalis apresentaram variações físicas, químicas e fitoquímicas ao longo do período de colheita, para as duas datas de semeadura. O desenvolvimento das plantas, após o transplantio, levou a acréscimo nos valores de massa, nos teores de sólidos solúveis, fenóis e carotenoides, assim como na razão SS/AT. Na coloração e na atividade antioxidante, os maiores valores foram obtidos na primeira colheita (120 dias. A semeadura realizada em setembro proporcionou a obtenção de frutos com melhor qualidade.

Evaluation of gamma and neutron irradiation effects on the properties of mica film capacitors

International Nuclear Information System (INIS)

Roy, Rajesh; Pandya, Arun

2005-01-01

We present an investigation of gamma and neutron radiation effects on mica film capacitors from an electrical point of view. We have studied quantitatively the effects of gamma and neutron irradiation on mica film capacitors of thickness, 20 and 40 μm (0.7874 and 1.5748 mil) with two different areas, 01 and 04 cm 2 . The capacitance has been measured at room temperature in the frequency range 100 Hz-10 MHz. Negligible change in the capacitance due to high gamma dose of 60 Co, 15 kGy at dose rate 0.25 kGy/h, has been observed. However, appreciable change in the capacitance has been observed due to low doses of fast neutrons (cumulative dose, 115 cGy) with flux ∼ 9.925 X 10 7 neutrons/cm 2 h from 252 Cf neutron source of fluence, 2.5 x 10 7 neutrons/s. We have also observed that the impact of gamma and neutron irradiation is more at frequencies higher than 10 kHz, These results show that the mica capacitors do not show any radiation response below 10 kHz. The study shows the radiation response of mica film capacitors to gamma and fast neutron radiations. Mica capacitors show low gamma radiation response in comparison to fast neutron radiation, because a total dose of kGy order has been given by gamma source and only few cGy dose has been given by fast neutron source. (author)

Complement-fixing antibodies against denatured HLA and MICA antigens are associated with antibody mediated rejection.

Science.gov (United States)

Cai, Junchao; Terasaki, Paul I; Zhu, Dong; Lachmann, Nils; Schönemann, Constanze; Everly, Matthew J; Qing, Xin

2016-02-01

We have found antibodies against denatured HLA class I antigens in the serum of allograft recipients which were not significantly associated with graft failure. It is unknown whether transplant recipients also have denatured HLA class II and MICA antibodies. The effects of denatured HLA class I, class II, and MICA antibodies on long-term graft outcome were further investigated based on their ability to fix complement c1q. In this 4-year retrospective cohort study, post-transplant sera from 975 kidney transplant recipients were tested for antibodies against denatured HLA/MICA antigens and these antibodies were further classified based on their ability to fix c1q. Thirty percent of patients had antibodies against denatured HLA class I, II, or MICA antigens. Among them, 8.5% and 21.5% of all patients had c1q-fixing and non c1q-fixing antibodies respectively. There was no significant difference on graft survival between patients with or without antibodies against denatured HLA/MICA. However, when these antibodies were further classified according to their ability to fix c1q, patients with c1q-fixing antibodies had a significantly lower graft survival rate than patients without antibodies or patients with non c1q-fixing antibodies (p=0.008). In 169 patients who lost renal grafts, 44% of them had c1q-fixing antibodies against denatured HLA/MICA antigens, which was significantly higher than that in patients with functioning renal transplants (25%, pantibodies were more significantly associated with graft failure caused by AMR (72.73%) or mixed AMR/CMR (61.9%) as compared to failure due to CMR (35.3%) or other causes (39.2%) (p=0.026). Transplant recipients had antibodies against denatured HLA class I, II, and MICA antigens. However, only c1q-fixing antibodies were associated with graft failure which was related to antibody mediated rejection. Copyright © 2015 Elsevier Inc. All rights reserved.

Vida académica de la facultad

OpenAIRE

Facultad de Medicina Revista

1999-01-01

Enciclopedia Académica sobre el Lenguaje en las Ciencias de la Salud / Convenio con la Universidad de Alcalá de Henares / Libro de Biología / XI Congreso de actualización en Rehabilitación Médica. Dolor crónico, diagnóstico y manejo integral / Primer Congreso Latinoamericano de Estudiantes de Nutrición y Dietética

La imagen y el cine en la enseñanza de la historia económica

Directory of Open Access Journals (Sweden)

Joan Miguel Tejedor Estupiñán

2018-01-01

Full Text Available Este artículo presenta el modelo de enseñanza desarrollado en las asignaturas de Historia Económica de Colombia e Historia Económica Mundial, en el programa de Economía de la Universidad Católica de Colombia, 2014 y 2015, cuyo objetivo es abordar los problemas históricos de la economía, a través de las fuentes tradicionales, complementadas con la fotografía, el cine, y demás herramientas que brindan las nuevas tecnologías de la comunicación. En la primera parte se describe el contexto de la educación en Colombia en lo que se refiere a la catedra de Historia Económica, en la segunda parte, se describe el modelo de enseñanza de la historia económica a través del cine, en la tercera parte se presenta un listado de films para complementar el proceso de enseñanza de la historia económica, en la cuarta parte se enumeran algunos recursos didácticos y fuentes de investigación que ofrece la internet, y finalmente se presentan las conclusiones.

Uso de rejeitos de granitos como matérias-primas cerâmicas

Directory of Open Access Journals (Sweden)

Menezes R. R.

2002-01-01

Full Text Available A indústria do beneficiamento de granito gera uma enorme quantidade de rejeitos, que poluem e degradam o meio ambiente. Assim este trabalho tem por objetivo caracterizar e avaliar as possibilidades de utilização dos rejeitos da serragem de granitos gerados pelas indústrias de beneficiamento da Região Nordeste, como matéria-prima cerâmica alternativa na produção de blocos e revestimentos cerâmicos. Foram coletadas amostras de resíduos da serragem de granito em empresas da Paraíba, Ceará e Pernambuco, em seguida foi realizada sua caracterização através da determinação da distribuição granulométrica, massa específica real e área específica (BET e de análise química, ATD, ATG, DRX, MEV. Após caracterização foram conduzidos ensaios tecnológicos com composições cerâmicas a fim de avaliar a possibilidade de adição dos resíduos em massas cerâmicas para confecção de blocos e revestimentos cerâmicos. Com base nos resultados verificou-se que os resíduos apresentam características físicas e mineralógicas semelhantes as das matérias-primas cerâmicas convencionais e que corpos cerâmicos formulados com resíduos apresentam características dentro das especificações da normalização brasileira tanto para blocos como para revestimentos cerâmicos.

Inmigrantes sirio-libaneses y sus prácticas económicas (ilegales en Colombia, 1880-1930

Directory of Open Access Journals (Sweden)

Ana Milena Rhenals Doria

2018-01-01

Full Text Available Entre 1880 y 1930, Colombia recibió un número significativo de inmigrantes procedentes de Siria y Líbano, quienes, a través de distintas actividades empresariales, terminaron siendo parte de la élite económica de varias ciudades colombianas. En este artículo estudio ese proceso de consolidación económica, haciendo énfasis en las prácticas económicas ilegales en las que incurrieron algunos de los inmigrantes siriolibaneses que se establecieron en el circuito comercial existente entre la provincia del Sinú, Cartagena y el Atrato. Argumento que actividades como la falsificación de monedas, el contrabando y el acaparamiento de tierras intervinieron en el proceso de acumulación de capital y de consolidación económica que algunos de estos inmigrantes lograron.

Cargas aerodinâmicas e pré-projeto estrutural de asa de aeronave de 50 passageiros

OpenAIRE

Lauro Cavalcanti de Sá

2010-01-01

Neste trabalho foi realizado o cálculo das cargas aerodinâmicas e o pré-projeto estrutural de asa de uma aeronave de 50 passageiros durante o Mestrado Profissionalizante em Engenharia Aeronáutica e Mecânica, ministrado pelo ITA em parceria com a EMBRAER, através do seu Programa de Especialização em Engenharia. Primeiramente, o modelo estrutural foi desenvolvido baseando-se nas características aerodinâmicas iniciais da aeronave, possibilitando que o programa de análise aerodinâmica BLWF fosse ...

Resinas quelantes amidoxímicas Amidoxime chelating resins

Directory of Open Access Journals (Sweden)

Fernanda M. B. Coutinho

1999-12-01

Full Text Available Resinas quelantes com grupos amidoxima foram sintetizadas por copolimerização em suspensão de acrilonitrila (AN e divinilbenzeno (DVB e subsequente modificação química dos grupos ciano por reação com hidroxilamina. Na copolimerização, a proporção de divinilbenzeno e o grau de diluição foram variados. Gelatina e carbonato de cálcio foram usados como estabilizadores de suspensão e sulfato de sódio foi adicionado para reduzir a solubilidade da acrilonitrila em água, por meio do efeito salting out. Os copolímeros de AN/DVB e as resinas amidoxímicas obtidos foram caracterizados por meio de densidade aparente, área específica, volume de poros e teor de nitrogênio. As resinas amidoxímicas foram também avaliadas em relação a capacidade de complexação de íons cobre.Chelating resins with amidoxime groups were synthesized by suspension copolymerization of acrylonitrile (AN and divinylbenzene (DVB and subsequent chemical modification of cyano groups by reaction with hydroxylamine. In the copolymerization, the proportion of divinylbenzene and the dilution degree were varied. Gelatin and calcium carbonate were used as suspension stabilizers and sodium sulphate was added in order to reduce acrylonitrile solubility in water, by salting out effect. The AN/DVB copolymers and amidoxime resins obtained were characterized by apparent density, surface area, pore volume and by the content of nitrogen. The amidoxime resins were also evaluated in relation to the complexation capacity of copper ion.

Neosporosis epidémica y endémica: descripción de dos eventos en bovinos para cría

Directory of Open Access Journals (Sweden)

Patricio M Calandra

2014-12-01

Full Text Available El objetivo de este trabajo es describir dos eventos producidos en la provincia de Buenos Aires en los cuales Neospora caninum estuvo asociado a la ocurrencia de abortos en bovinos de cría para carne. En uno de ellos se registraron 11 abortos en 57 vaquillonas durante 45 días, en este evento fue 5 veces más probable que una vaquillona que sufrió un aborto fuera seropositiva a N. caninum que una que no lo sufrió (odds ratio [OR] = 4,9 IC 1,2-19,9 (p 0,05. Se analizaron dos fetos de cada evento: estos resultaron negativos a otros patógenos de la reproducción, aunque presentaron anticuerpos específicos y lesiones histopatológicas compatibles con infecciones por N. caninum. Estos resultados sugieren dos posibles modalidades de presentación de abortos en bovinos causados por N. caninum: una epidémica, como la del primer evento aquí referido, y una endémica, como la del segundo.

El etanol como materia prima petroquímica

Directory of Open Access Journals (Sweden)

Luis M. Carballo

1981-07-01

Full Text Available En este trabajo se presentan los aspectos relevantes de un programa a de investigación, aprobado por el CINDEC y COLCIENCIAS, sobre el desarrollo y estudio cinético de catalizadores para algunas reacciones químicas en las que el etanol está involucrado como reactante.

La construcción de identidades docentes como constructo de estructura y dinámica sistémicas: argumentación y virtualidades teóricas y prácticas

Directory of Open Access Journals (Sweden)

Amélia Lopes

2007-01-01

Full Text Available Resaltando la importancia de que, en los estudios sobre la identidad docente, se invierta en la configuración de una perspectiva teórica integrada y elaborada y teniendo como referente la biografía investigativa de la autora, este artículo tiene como objetivos presentar la “construcción de identidades profesionales docentes” como un constructo de estructura y dinámica sistémicas e indicar sus virtualidades teóricas y prácticas. Tras una exposición inicial sobre las concepciones de identidad enmarcadas por el interaccionismo simbólico y el sentido que en ellas se vislumbra, se desarrolla una argumentación en dos fases: una relativa a la crisis de identidad de los profesores y otra referente a la construcción de nuevas identidades. Se concluye destacando las virtualidades de considerar a la construcción de nuevas identidades docentes como un constructo de estructura y dinámica sistémicas, concretamente: la posibilidad de que se relacione la construcción de identidades profesionales y los procesos de profesionalización docente; y la importancia de que se piense la formación de profesores a los diversos niveles del sistema, teniendo en cuenta sus especificidades e interacciones

La Química, la Ingeniería Química y su relación con otras disciplinas La Química, la Ingeniería Química y su relación con otras disciplinas

Directory of Open Access Journals (Sweden)

Antonio Valiente Barderas

2012-02-01

Full Text Available Chemical Engineering as such has a little more than a hundred years of existence. During this time, his development has generated research, data and books which made innovations in the curriculum and new paradigms in education. The development of this discipline has influenced the creation or modification of others such as Environmental Engineering, Food Engineering, Electrochemical Engineering, Metallurgical Engineering, etc. The future presents new challenges and opportunities for development in the area of biofuels, nanotechnology and climate control.La Ingeniería Química, como tal, tiene apenas un poco más de cien años de existencia. Durante ese tiempo la enseñanza de la misma ha ido cambiando conforme se generaron investigaciones, datos y libros que produjeron innovaciones en el currículo y nuevos pa­radigmas de la enseñanza. El desarrollo de esta disciplina ha incidido en la creación o modificación de otras más, tal como la Ingeniería Ambiental, la Ingeniería de Alimentos, la Bioingeniería, la Ingeniería Electroquímica y la Ingeniería Metalúrgica, etc. En el futuro se presentan nuevos retos y oportunidades de desarrollo en el área de los biocombustibles, la nanotecnología, los nuevos materiales y el control climático.

EL PROTEOMA DEL TEJIDO ADIPOSO SUBCUTÁNEO MUESTRA HETEROGENEIDAD ANATÓMICA

Science.gov (United States)

Martos-Moreno, G.A.; Sackmann-Sala, L.; Berryman, D.E.; Blome, D.W.; Argente, J.; Kopchick, y J.J.

2015-01-01

Introducción El tejido adiposo blanco (TAB) subcutáneo (Sc) humano podría variar dependiendo de su localización anatómica, con diferencias en su perfil proteómico. Pacientes y métodos Se obtuvieron aspirados de TAB-Sc de seis mujeres con IMC >25 kg/m2, sometidas a liposucción. Dicho TAB-Sc se obtuvo de seis localizaciones anatómicas: abdominal superior e inferior, muslo, dorsal, flanco y cadera, analizándose su perfil proteómico mediante electroforesis bidimensional. En muslo y abdomen superior se compararon, además, las muestras obtenidas de las dos capas del TAB-Sc (profunda y superficial). Resultados Se detectaron 21 proteínas que mostraban una intensidad de expresión diferente entre las seis localizaciones anatómicas y 14 entre las capas superficial y profunda de una misma región. Entre las proteínas identificadas se incluyen: vimentina (proteína estructural); proteínas “heat-shock” (HSPs), superóxido-dismutasa, (estrés/chaperoninas); proteína fijadora de ácidos grasos 4 (FABP-4) y alfa-enolasa (metabolismo lipídico y de los hidratos de carbono, respectivamente) y ATP-sintetasa (producción de energía). Entre las regiones estudiadas, el TAB-Sc dorsal mostraba un perfil proteómico particular, con menor expresión de proteínas implicadas en la producción de energía y metabolismo (ATP-sintetasa, alfa-enolasa, HSPs y FABP-4) que el resto de regiones. Conclusiones Los niveles de expresión de diversas proteínas en el TAB-Sc humano no son homogéneos, difiriendo entre localizaciones anatómicas. Esto sugiere la existencia de diferencias funcionales en el TAB-Sc de acuerdo con su localización anatómica, lo que debe considerarse antes de asumir la extrapolación de los datos derivados del TAB-Sc de una determinada localización al de otras partes de la anatomía. PMID:23228439

Effect of waste mica on transfer factors of 134Cs to spinach and lettuce

International Nuclear Information System (INIS)

Sreenivasa Chari, M.; Manjaiah, K.M.; Sachdev, P.; Sachdev, M.S.

2011-01-01

A greenhouse pot culture experiment was conducted to study the effect of graded levels of waste mica (0, 10, 20 and 40 g kg -1 ) on reducing the radiocesium uptake by spinach (Spinacia olerecea L) and lettuce (Lactuca sativa L.) grown in 134 Cs-contaminated (at 37 k Bq kg -1 soil) Inceptisols, Vertisols and Ultisols. The biomass yield, and potassium content and its uptake by crops have been significantly improved by waste mica application. The crops grown in Vertisols recorded higher biomass yield, and K content and its uptake as compared with Inceptisols and Ultisols. The average 134 Cs transfer factor values recorded were: 0.21, 0.17 and 0.26 at the first cutting, 0.15, 0.12 and 0.28 at the second cutting and 0.07, 0.05 and 0.23 at the third cutting from Inceptisols, Vertisols and Ultisols, respectively. Waste mica significantly suppressed radiocesium uptake, the effect being more pronounced at 40 g mica kg -1 soil. There exists an inverse relationship between the 134 Cs transfer factors with plant potassium content and also the K uptake by the crops. (authors)

Experiments on the incorporation of concentrated solutions of fission products in glasses and micas

International Nuclear Information System (INIS)

Bonniaud, R.; Cohen, P.; Sombret, C.

1958-01-01

1) The plants designed for extracting the plutonium of the G1, G2, G3 reactors fuel rods will produce extremely concentrated solutions of fission products. 2) Let us consider a synthetic solution of the 'G2' type: (2N NO 3 H - 2,25 meq/cm 3 AI +++ - 5.10 -3 134 Cs - 137 Cs tracer). We made various glasses and micas by adding and mixing the necessary adjuvants and baking (900 to 1400 deg. C) in a graphite crucible. 3) The products obtained had either the shape of a cylindrical pellet or were reduced into a fine powder. They were mixed with 300 cm 3 of synthetic sea water during variable periods of time in order to study leaching of the activity. 4) Experiments were first carried on caesium because of its solubility. 5) Fabrication of micas on a large scale sets many technological problems more difficult to solve (1400 deg. C) than in the case of glasses (1000 deg. C). A comparative study on both micas and glasses showed that leaching of activity was more important in the micas. (author) [fr

EL CURRÍCULO UNIVERSITARIO COMO ESCENARIO DE TENSIONES SOCIALES Y ACADÉMICAS

OpenAIRE

Mercedes Collazo

2017-01-01

Los retos que hoy plantean al currículo universitario los nuevos requerimientos de ajuste entre educación superior, empleo y sociedad en el marco de las dinámicas de globalización advierten la necesidad de construir una mirada académica que profundice los alcances y límites de los campos de formación, en razón de sus estructuras de conocimiento implicadas y en el contexto de sus particulares tradiciones profesionales y educativas. En tal sentido, el presente trabajo procura abordar el...

Avaliação econômica de plantações de eucalipto submetidas a desbaste

Directory of Open Access Journals (Sweden)

Soares Thelma Shirlen

2003-01-01

Full Text Available O objetivo deste estudo foi determinar, através de métodos de avaliação econômica, a idade econômica de corte de plantações de eucalipto submetidas a desbaste. Para tanto, foram utilizados dados de um experimento de desbastes estabelecido na região nordeste da Bahia. Foram consideradas as variações de intensidades de desbaste (0, 20, 40 e 60% de retirada em área basal para projeções realizadas em diferentes classes de local. O método de avaliação econômica utilizado foi o valor anual equivalente. Na análise de sensibilidade foram levadas em conta taxas de desconto de 6, 9 e 12%. Os resultados evidenciaram que a rotação econômica propicia maior lucratividade quando se realiza desbaste.

Effect of protein solution components in the adsorption of Herbaspirillum seropedicae GlnB protein on mica.

Science.gov (United States)

Ferreira, Cecília F G; Benelli, Elaine M; Klein, Jorge J; Schreiner, Wido; Camargo, Paulo C

2009-10-15

The adsorption of proteins and its buffer solution on mica surfaces was investigated by atomic force microscopy (AFM). Different salt concentration of the Herbaspirillum seropedicae GlnB protein (GlnB-Hs) solution deposited on mica was investigated. This protein is a globular, soluble homotrimer (36kDa), member of PII-like proteins family involved in signal transducing in prokaryote. Supramolecular structures were formed when this protein was deposited onto bare mica surface. The topographic AFM images of the GlnB-Hs films showed that at high salt concentration the supramolecular structures are spherical-like, instead of the typical doughnut-like shape for low salt concentration. AFM images of NaCl and Tris from the buffer solution showed structures with the same pattern as those observed for high salt protein solution, misleading the image interpretation. XPS experiments showed that GlnB protein film covers the mica surface without chemical reaction.

¿Oferta o renovación académica?

OpenAIRE

Serani Prádenas, Edmundo

2017-01-01

Aunque sin divulgar una definición, lo que es altamente preocupante, las autoridades universitarias han legitimado el término "Renovación de la Oferta Académica", el que en nuestra opinión tiene importantes limitaciones.

Measurement of proton polarization in the reaction. gamma. /ital p//r arrow//ital p/. pi. /sup 0/ at an angle theta/sup *//sub. pi. /sup 0//=80/degree/ in a linearly polarized photon beam

Energy Technology Data Exchange (ETDEWEB)

Avakyan, R. O.; Avakyan, E. O.; Avetisyan, A. E.; Aivazyan, R. B.; Arestakesyan, G. A.; Bagdasryan, A. S.; Vartapetyan, G. A.; Garibyan, Y. A.; Eganov, V. S.; Karapetyan, A. P.; and others

1988-12-01

Measurements are reported of the energy dependence of the /ital p//sub /ital xz// and /ital P//sub /ital y// components of the polarization vector of the recoil protons in the reaction ..gamma../ital p//r arrow//ital p/..pi../sup 0/ for a ..pi../sup 0/-meson production angle theta/sup *//sub ..pi../sup 0// =80/degree/ in the c.m.s. in the ..gamma..-ray energy range /ital E//sub ..gamma../=730--1066 MeV. The experimental data are compared with the results of various phenomenological analyses.

Vida académica de la facultad

Directory of Open Access Journals (Sweden)

Facultad de Medicina Revista

1999-07-01

Full Text Available Enciclopedia Académica sobre el Lenguaje en las Ciencias de la Salud / Convenio con la Universidad de Alcalá de Henares / Libro de Biología / XI Congreso de actualización en Rehabilitación Médica. Dolor crónico, diagnóstico y manejo integral / Primer Congreso Latinoamericano de Estudiantes de Nutrición y Dietética

Gestão econômica de investimentos em ativos fixos

OpenAIRE

Catelli,Armando; Parisi,Cláudio; Santos,Edilene Santana

2003-01-01

Num ambiente global de intensas mudanças competitivas, a mensuração dos ativos, especificamente dos ativos fixos, requer a superação da rigidez dos custos históricos e da depreciação linear, próprios da contabilidade tradicional, e a adoção de critérios que permitam avaliar adequadamente a realidade econômica desses ativos. Partindo da premissa de que o patrimônio líquido deve representar o valor da empresa, e de que sua variação expressa o resultado econômico, o Sistema de Gestão Econômica -...

Modelagem de uma unidade de produção para caprinos leiteiros utilizando a dinâmica de sistemas

OpenAIRE

Guimarães, Vinicius Pereira

2007-01-01

O trabalho foi desenvolvido buscando abordar as características de dinâmica, complexidade e inter- relacionamento de um sistema de produção de caprinos. Buscou-se, através da metodologia de modelagem e simulação Dinâmica de Sistemas, identificar o impacto na dinâmica e rentabilidade econômica de rebanhos caprinos leiteiros provocados por modificações no manejo reprodutivo, mortalidade, qualidade do alimento e na idade para o início da vida reprodutiva em cabritas. Buscou-se também avaliar a u...

PODOLSKY'S ELECTRODYNAMICS UNDER A CHIRAL APPROACH ELECTRODINÁMICA DE PODOLSKY BAJO UN ENFOQUE QUIRAL

OpenAIRE

Héctor Torres-Silva

2008-01-01

In this paper we show that a new approach leads to Maxwell's and Podolsky's electrodynamics, provided we start from chiral constitutive relations instead of the usual Coulomb's law.En este trabajo se muestra que un nuevo esquema conduce a la electrodinámica de Maxwell y a la electrodinámica de Podolsky, partiendo con relaciones constitutivas quirales en lugar de la usual ley de Coulomb.

La polémica del nacionalismo

Directory of Open Access Journals (Sweden)

Germán Posada

1961-10-01

Full Text Available La polémica empezó con el artículo de Hernando Téllez, hace veinte días. Con el pretexto de defender a los escritores de su propia generación, a quienes, según él, se viene acusando sistemáticamente de producir una literatura desarraigada y ausente de la vida nacional, Téllez se lanzó a combatir las teorías de " nacionalismo literario'' que actualmente se agitan en Colombia.

Dinámica económica e institucionalización de la tributación directa. Trasnformaciones institucionales el caso de administración de impuestos 1920-1935

OpenAIRE

Oscar Rodríguez Salazar

1999-01-01

Las tres primeras décadas del presente siglo son el escenario de profundas transformaciones en la estructura económica del país y en el modelo institucional. El desarrollo de la economía cafetera, el acceso a la economía de crédito internacional, los cambios en la política económica, la ampliación de la infraestructura, el acelerado proceso de urbanización, los cambios demográficos, la proletarización de un contingente considerable de masas campesinas y el inicio del proceso de industrializac...

Rare earth ion controlled crystallization of mica glass-ceramics

International Nuclear Information System (INIS)

Garai, Mrinmoy; Karmakar, Basudeb

2016-01-01

In understanding the effects of rare earth ions to control the crystallization and microstructure of alkaline boroaluminosilicate system, the CeO_2, Nd_2O_3, Sm_2O_3 and Gd_2O_3 doped K_2O−MgO−B_2O_3−Al_2O_3−SiO_2−F glasses were synthesized by melt-quenching at 1550 °C. Higher density (2.82–3.06 g cm"−"3) and thermal stability (glass phase) is experiential on addition of rare earth content, which also affects in increasing the glass transition temperature (T_g) and crystallization temperature (T_c). Decrease of thermal expansion in glasses with rare earth ion content is maintained by the stabilization of glass matrix owing to their large cationic field strength. A significant change in the non-isothermal DSC thermogram observed at 750–1050 °C is attributed to fluorophlogopite crystallization. Opaque glass-ceramics were prepared from such glasses by single step heat-treatment at 1050 °C; and the predominant crystalline phases are identified as fluorophlogopite mica, KMg_3(AlSi_3O_1_0)F_2 by XRD and EDX analysis. The compact glass-ceramic microstructure by the agglomeration of fluorophlogopite mica crystallites (crystal size ∼ 100–500 nm, FESEM) is achieved in attendance of rare earth ion; and such microstructure controlled the variation of density, thermal expansion and microhardness value. Higher thermal expansion (11.11–14.08 × 10"−"6/K at 50–800 °C and 50–900 °C) of such glass-ceramics approve that these rare earth containing glasses can be useful for high temperature vacuum sealing application with metal or solid electrolyte. The increase of Vickers microhardness (5.27–5.61 GPa) in attendance of rare earth ions is attributed to the compact crystallinity of fluorophlogopite mica glass-ceramic microstructure. - Highlights: • Synthesis of rare earth oxide doped alkaline boroaluminosilicate glasses. • Development of opaque fluorophlogopite mica glass-ceramics by single-step heat treatment. • Nanocrystalline glass

Daniel Kahneman y la Psicología Económica

Directory of Open Access Journals (Sweden)

ISMAEL QUINTANILLA

2002-01-01

Full Text Available La reciente concesión del Premio Nobel de Economía a un psicólogo, aunque no sea cosa nueva, puede ser un excelente motivo de reflexión científica y de consideración profesional. La psicología ha estado demasiado tiempo alejada de lo que podría denominarse la conducta social más consuetudinaria, la que componen nuestras decisiones económicas y nuestras conductas como consumidores. No ha sido este un campo que haya gozado de muchas simpatías por parte de nuestros colegas. Quizá como consecuencia de una visión excesivamente estrecha de las posibilidades explicativas y aplicativas de la Psicología Económica. Puede que también se deba a un cierto desconocimiento de esta especialidad -o campo de investigación y desarrollo- de la Psicología social. De hecho, apenas existente como materia de estudios en las Facultades de psicología españolas cuando es cosa bastante corriente en la mayor parte de las europeas (Webley y Walker, 1999. El artículo resume y sintetiza los resultados de las investigaciones de la concesión del Premio Nobel de Economía a Vernon Smith y David Kahneman, reflexiones en base al futuro de la psicología Económica.

Parte 4: Estudio comparativo de la composición química

Directory of Open Access Journals (Sweden)

L. R. Carballo-Abreu

2004-01-01

Full Text Available Se estudió comparativamente, mediante análisis estadístico la composición química de la madera de E. saligna Smith, Corymbia citriodora y E. pellita F. Muell, a tres alturas del fuste comercial (25, 55 y 85 % en muestras procedentes de las Empresas Forestales Integrales (EFI de Macurije y Guanahacabibes en la provincia de Pinar del Río, Cuba. Los resultados obtenidos de la composición química, se trataron mediante un programa estadístico SPSS para Windows, donde no todas las variables analizadas muestran influencias estadísticas en la caracterización química de las especies. Los resultados manifiesta una mejor agrupación con especto a la especie que a la altura del fuste comercial entre las especies. La madera de Corymbia citriodora presenta los mayores contenidos de celulosa, los menores contenidos de lignina y de sustancias extraíbles, siendo la especie más atractiva desde el punto de vista químico para ser utilizada en la Industria de celulosa y papel.

Los nuevos dominios de la ciencia económica

Directory of Open Access Journals (Sweden)

Bejarano Jesús Antonio

1999-12-01

Full Text Available Hace algo más de diez años, siendo Decano de la Facultad de Ciencias Económicas de la Universidad Nacional, tuve el honor de ser el primer expositor en el primer congreso de estudiantes de economía del país. Once años después, recae de nuevo en mí ese honor, y por ello debo expresar mi gratitud a los estudiantes organizadores de este cuento. Entre aquel primer congreso y éste se transformó no sólo el panorama del quehacer profesional sino también el panorama global de la ciencia económica, y creo que en forma radical. En poco más de veinte años, desde comienzos de los años setenta, se abrieron nuevos rumbos que, sin duda, quienes hoy son estudiantes seguirán en el futuro.

La disponibilidad de nutrientes para las plantas, consecuencia de interacción, química, biológica y bioquímica

Directory of Open Access Journals (Sweden)

Martha Medina

2007-10-01

Full Text Available La nutrición vegetal depende de varios factores;entre ellos: minerales, microorganismos y moléculas orgánicas. Éstos a la vez están relacionados con las condiciones físicas, químicas y biológicas del suelo. Las adiciones de materia orgánica o de abonos orgánico-minerales favorecen esta condición, porque, contienen moléculas que alimentan poblaciones microbianas que segregan las enzimas requeridas para solubilizar minerales o mineralizarla, pero no suplen las necesidades de la mayoría de los cultivos. Esta dinámica está determinada por la presencia de elementos que intervienen en la fijación del nitrógeno o la producción de ácidos orgánicos que liberan fósforo, pero que también pueden afectar la biodisponibilidad de varios nutrientes o las poblaciones microbianas.

Plagio e integridad académica en Alemania

Directory of Open Access Journals (Sweden)

2016-07-01

Full Text Available Alemania es quizá uno de los países europeos que, ya desde el siglo XVIII, ha mantenido un debate público más intenso sobre prácticas científicas y académicas deshonestas, relacionadas especialmente con tesis doctorales. Este debate fue especialmente productivo a finales del siglo XIX, dando lugar desde entonces, para evitar estas prácticas inaceptables, a la obligatoriedad de publicar todas las tesis doctorales, como requisito previo a la expedición del título de doctor por cualquier universidad alemana. Este trabajo analiza los avances más importantes en plagio e integridad académica en Alemania, especialmente después del escándalo surgido en 2011 a raíz del plagio de la tesis doctoral del Ministro de Defensa Guttenberg, como son la creación de una eficaz metodología colaborativa de investigación del plagio en trabajos científicos o académicos utilizando Internet y las redes sociales, materializada en la Wiki «VroniPlag». También se describe someramente en este trabajo la consolidación definitiva de la figura del «Defensor de la Ciencia», como instrumento de ámbito nacional para prevenir, gestionar y combatir la deshonestidad científica, aparte de la publicación en 2013 de una nueva versión del manual de referencia al respecto «Sicherung guter wissenschaftlicher Praxis». Por último se analizan las conclusiones de la experiencia alemana relacionada con la ética académica, también desde una perspectiva histórica, pues sus recientes logros y avances pueden servir de referencia a otros países europeos.

The crystal orientation relation and macroscopic surface roughness in hetero-epitaxial graphene grown on Cu/mica

International Nuclear Information System (INIS)

Qi, J L; Nagashio, K; Nishimura, T; Toriumi, A

2014-01-01

Clean, flat and orientation-identified graphene on a substrate is in high demand for graphene electronics. In this study, the hetero-epitaxial graphene growth on Cu(111)/mica(001) by chemical vapor deposition is investigated to check the applicability for top-gate insulator research on graphene, as well as graphene channel research, by transferring graphene on to SiO 2 /Si substrates. After adjusting the graphene growth conditions, the surface roughness of the graphene/Cu/mica substrate and the average smoothed areas are ∼0.34 nm and ∼100 μm 2 , respectively. The orientation of graphene in the graphene/Cu/mica substrate can be identified by the hexagonal void morphology of Cu. Moreover, we demonstrate a relatively high mobility of ∼4500 cm 2 V −1 s −1 in graphene transferred on the SiO 2 /Si substrate. These results suggest that the present graphene/Cu/mica substrate can be used for top-gate insulator research on graphene. (papers)

CULTURAS ACADÉMICAS: ENTRE REINVENCIÓN Y CONTRABANDO

Directory of Open Access Journals (Sweden)

Kathya Araujo

2015-01-01

Full Text Available Sobre la base del análisis de una historia personal de desplazamiento entre academias (peruana y chilena, y la reinvención y el contrabando que toda migración supone, este artículo argumenta de qué manera frente a las nuevas modalidades de evaluación (los rankings, la búsqueda de isomorfismo de las estructuras argumentativas y las formas lingüísticas o incluso la ficción de sociologías globales, se mantienen vivas culturas académicas particulares. En este marco, la reflexión se organiza mostrando que detrás de la singularidad de los estilos intelectuales, formas de sociabilidad profesionales e incluso formas lingüísticas de cada una de ellas, lo que se revela es la manera en la que cada cultura académica local responde desde tradiciones diversas a desafíos político sociales distintos y con ello su rol de compromiso público y crítico.

PODOLSKY'S ELECTRODYNAMICS UNDER A CHIRAL APPROACH ELECTRODINÁMICA DE PODOLSKY BAJO UN ENFOQUE QUIRAL

Directory of Open Access Journals (Sweden)

Héctor Torres-Silva

2008-11-01

Full Text Available In this paper we show that a new approach leads to Maxwell's and Podolsky's electrodynamics, provided we start from chiral constitutive relations instead of the usual Coulomb's law.En este trabajo se muestra que un nuevo esquema conduce a la electrodinámica de Maxwell y a la electrodinámica de Podolsky, partiendo con relaciones constitutivas quirales en lugar de la usual ley de Coulomb.

Rutas Gastronómicas y Desarrollo local: un ensayo de conceptualización en Cataluña

Directory of Open Access Journals (Sweden)

Zeinab Jeambey

2016-01-01

Full Text Available Las rutas gastronómicas estimulan el desarrollo local sostenible de zonas agrícolas, atrayendo hacia ellas un turismo de calidad. Cataluña promociona varias rutas gastronómicas que, sin embargo, carecen de estructura y contenido coherente. En este trabajo, se consultó a expertos en el ámbito de turismo y gastronomía sobre su percepción de lo que debe ser una ruta gastronómica que contribuya al desarrollo local. Según ellos, no existen en Cataluña pautas que rijan su diseño y funcionamiento. Una ruta gastronómica se define como un producto turístico estructurado que contribuye al mantenimiento del paisaje, la difusión de la cultura local, el desarrollo económico y el posicionamiento del territorio. Clave para su éxito es su organización, la coherencia del discurso y las responsabilidades de los agentes involucrados. Se valora el papel del productor. Se recomienda la estandarización de la definición de ruta gastronómica y la elaboración de pautas para su diseño y su estructuración.

Política econômica e Estado Economic policy and State

Directory of Open Access Journals (Sweden)

Giovani Clark

2008-04-01

Full Text Available O artigo enfoca, pela óptica do direito econômico, as influências das políticas econômicas privadas (basicamente do capital transnacional e dos entes internacionais sobre as políticas econômicas públicas, especialmente as realizadas pelos Estados em desenvolvimento. Enfatiza a mutação do neoliberalismo de regulamentação para o de regulação como exigência dos poderes econômicos privados, identificando entre os seus resultados o enfraquecimento do Estado e a descrença na democracia. E, ainda, defende a existência de espaços para a execução de ações econômicas endógenas por parte dos Estados Nacionais, a fim de viabilizar a eficácia de suas Constituições econômicas e suprir as carências de seus povos.This paper deal with, by Economical Law view, the effects of private economic policy, essentially of foreign capital, and the international organizations above the public economic policy, mainly that politics performed by the development nations. Lay emphasis on the mutation of the regulatory New Liberalism to the regulation as demand of private economic powers, recongnized enter their results: The decline of the State and the unbelief of democracy. Defends existence of spaces for the execution of endogenous economic actions by part of National States, for the purpose of execute effectiveness of their economical constitution and supply the shortage of their people.

Economic policy and state Política econômica e estado

Directory of Open Access Journals (Sweden)

Giovani Clark

2007-12-01

Full Text Available This paper deal with, by Economical Law view, the effects of private economic policy, essentially of foreign capital, and the international organizations above the public economic policy, mainly that politics performed by the development nations. Lay emphasis on the mutation of the regulatory New Liberalism to the regulation as demand of private economic powers, recongnized enter their results: The decline of the State and the unbelief of democracy. Defends existence of spaces for the execution of endogenous economic actions by part of National States, for the purpose of execute effectiveness of their economical constitution and supply the shortage of their people.O artigo enfoca, pela ótica do Direito Econômico, as influências das políticas econômicas privadas (basicamente do capital transnacional e dos entes internacionais sobre as políticas econômicas públicas, principalmente as realizadas pelos Estados em desenvolvimento. Enfatiza a mutação do Neoliberalismo de Regulamentação para o de Regulação como exigência dos poderes econômicos privados, identificando entre os seus resultados: o enfraquecimento do Estado e a descrença na Democracia. E ainda, defende a existência de espaços para a execução de ações econômicas endógenas por parte dos Estados nacionais, a fim de viabilizar a eficácia de suas Constituições Econômicas e suprir as carências de seus povos.

Uma abordagem investigativa do trabalho experimental no ensino da química a alunos não-químicos na universidade

OpenAIRE

Figueiredo, Margarida; Maia, Maria Elisa

2005-01-01

Pretende-se divulgar os resultados de um estudo sobre a implementação de um tipo de abordagem ao Trabalho Experimental de Química, cujos objectivos são: - Contribuir para motivar os alunos para a aprendizagem da Química; - Contribuir para melhorar o sucesso na formação em Química dos alunos que não sendo de Química necessitam de fazer aprendizagens nesse domínio; - Contribuir para uma revalorização do trabalho experimental enquanto estratégia privilegiada para o ensino da Química....

SEMIÓTICA E MORFODINÂMICA. UMA BUSCA E SUAS VICISSITUDES

Directory of Open Access Journals (Sweden)

Ivã Carlos Lopes

2014-07-01

Full Text Available Entre as discussões que marcaram a breve história da semiótica desde os princípios de sua implantação disciplinar, focalizamos, nesta ocasião, as chamadas propostas "morfodinâmicas" que, na comunidade semiótica, tiveram curso principalmente durante as décadas de 1980 e 1990, até se tornarem menos frequentadas a partir da virada do novo século. A fim de ilustrar nossa explanação, mostramos o modo de funcionamento de uma esquematização morfodinâmica das modalidades epistêmicas, lidas com auxílio de uma das "catástrofes elementares" de René Thom, debatendo sua contribuição para a inteligibilidade dessa região conceitual

Compensaciones económicas ante conflictos de uso del suelo

Directory of Open Access Journals (Sweden)

Polanco Jorge Andrés

2009-10-01

Full Text Available Existen conflictos de uso del suelo que pretenden ser atenuados con compensaciones económicas. En este trabajo se estiman los conflictos existentes en el Sistema de Páramos Alto-Andinos de Antioquia, comparando las restricciones al uso del suelo con la dinámica de la frontera agropecuaria. Las compensaciones se calculan en función de la renta de la tierra y se evalúa su financiación con recursos públicos y privados considerando las inversiones municipales y la solvencia del sector productivo. Los resultados muestran que los conflictos son mayores donde la frontera es activa. Las compensaciones logran ser asumidas por los municipios pequeños con tierras poco rentables, mientras que los grupos económicos pueden financiarlas dependiendo de la gobernanza.

Morfoanatomia e histoquímica de Brosimum gaudichaudii Trécul (Moraceae)

OpenAIRE

Jacomassi,Ezilda; Moscheta,Ismar Sebastião; Machado,Sílvia Rodrigues

2007-01-01

Brosimum gaudichaudii, conhecida como mamacadela, é espécie comum nos cerrados, com grande valor na medicina popular e na indústria de medicamentos. A casca da raiz e do caule é empregada no tratamento do vitiligo, sendo o bergapteno e psoraleno, duas furanocumarinas, responsáveis pela ação farmacológica. Neste trabalho são apresentadas a caracterização morfoanatômica e a histoquímica de órgãos vegetativos de B. gaudichaudii, com informações sobre o embrião e o desenvolvimento pós-seminal. Am...

Apuntes de historia de la química industrial en México

OpenAIRE

Bucay, Benito

2001-01-01

La química industrial en México desciende de las actividades mineras de la época de la Colonia. Su despegue ocurre durante la Segunda Guerra Mundial y tiene un fuerte desarrollo en varios frentes entre 1960 y 1990. A partir de entonces, se ha dado un proceso de consolidación y reestructura como consecuencia de la apertura económica, lo cual ha conducido a una reducción en el número de participantes y actividades, quedando sólo aquéllas que tienen una base firme de tecnología y capacidad que l...

Estabilidad del color de las cerámicas de disilicato de litio.

OpenAIRE

Cedeño Salazar, Rosario

2016-01-01

La gran demanda de tratamientos estéticos por parte de los pacientes, supone un reto para los rehabilitadores orales, por lo que siempre están en búsqueda del material ideal. Las cerámicas dentales, poseen características que le permiten mimetizar la apariencia de los dientes naturales, por sus propiedades físicas y químicas, las cuales dependen de su composición. Poseen una fase vítrea que le aporta características estéticas y una fase cristalina que le aporta propiedades mecánicas. Clín...

Redes empresariales y estabilidad macroeconómica : una propuesta teórica.

OpenAIRE

Rodríguez Oviedo, Gilberto José

2016-01-01

En esta tesis se hace una revisión de la concentración empresarial así como su afectación al mercado. Se revisa el concepto de redes en el contexto de recesión económica, y algunos tipos de equilibrio general como los macroeconómicos, de generaciones traslapadas y los computables. Con esta introducción se hace un breve análisis de algunos modelos de equilibrio general realizados para el Ecuador en diversas áreas de aplicación como impuestos, comercio exterior, protección económica y social. C...

Insuficiencia dinámica, crecimiento y desempleo en México, 1974-2012

OpenAIRE

Blanca L. Avendaño Vargas; Ignacio Perrotini Hernández

2015-01-01

El artículo presenta una reformulación de la hipótesis de insuficiencia dinámica de Prebisch (1970), analiza la teoría dinámica de Harrod (1939), la ley Kaldor-Verdoorn (Kaldor, 1966; 1967) y la teoría del crecimiento endógeno de Thirlwall (1969; 2000). A posterioriestudiamos los determinantes del crecimiento económico y del desempleo en México durante el periodo 1974-2012. Con base en el análisis empírico, sostenemos que una baja tasa de acumulación genera una reducida absorción de empleo, u...

Dinámica de sistemas en la gestión de inventarios

OpenAIRE

Daniel Alejandro Agudelo Serna; Yohana Marcela López Rivera

2018-01-01

En el presente artículo se estudia el proceso de gestión de inventarios por medio de la dinámica de sistemas, como herramienta metodológica que permite conocer el comportamiento de las variables de acuerdo a sus relaciones y a las decisiones que se tomen teniendo en cuenta su causalidad y realimentación. El desarrollo del documento está determinado por una revisión de conceptos teóricos relacionados con la gestión de inventarios y dinámica de sistemas, seguido por una revisión de lit...

Curly arrows meet electron density transfers in chemical reaction mechanisms: from electron localization function (ELF) analysis to valence-shell electron-pair repulsion (VSEPR) inspired interpretation.

Science.gov (United States)

Andrés, Juan; Berski, Sławomir; Silvi, Bernard

2016-07-07

Probing the electron density transfers during a chemical reaction can provide important insights, making possible to understand and control chemical reactions. This aim has required extensions of the relationships between the traditional chemical concepts and the quantum mechanical ones. The present work examines the detailed chemical insights that have been generated through 100 years of work worldwide on G. N. Lewis's ground breaking paper on The Atom and the Molecule (Lewis, G. N. The Atom and the Molecule, J. Am. Chem. Soc. 1916, 38, 762-785), with a focus on how the determination of reaction mechanisms can be reached applying the bonding evolution theory (BET), emphasizing how curly arrows meet electron density transfers in chemical reaction mechanisms and how the Lewis structure can be recovered. BET that combines the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT) provides a powerful tool providing insight into molecular mechanisms of chemical rearrangements. In agreement with physical laws and quantum theoretical insights, BET can be considered as an appropriate tool to tackle chemical reactivity with a wide range of possible applications. Likewise, the present approach retrieves the classical curly arrows used to describe the rearrangements of chemical bonds for a given reaction mechanism, providing detailed physical grounds for this type of representation. The ideas underlying the valence-shell-electron pair-repulsion (VSEPR) model applied to non-equilibrium geometries provide simple chemical explanations of density transfers. For a given geometry around a central atom, the arrangement of the electronic domain may comply or not with the VSEPR rules according with the valence shell population of the considered atom. A deformation yields arrangements which are either VSEPR defective (at least a domain is missing to match the VSEPR arrangement corresponding to the geometry of the ligands), VSEPR compliant

AVALIAÇÃO ECONÔMICA DO TRÁFICO DE DROGAS NO ESTADO DO ACRE

Directory of Open Access Journals (Sweden)

Rennan Bitts de Lima Lima

2011-09-01

Full Text Available A decisão de um indivíduo em migrar para a atividade econômica criminosa do tráfico de drogas é influenciada por um conjunto de características econômicas e sociais. Diante disso, levando-se em conta que o tráfico de drogas está relacionado à prática de uma grande quantidade de outros crimes, a proposta deste trabalho consiste na produção de informações que sirvam de subsídio para ações de agentes públicos e privados que visem combater a criminalidade. De forma geral, o objetivo deste trabalho consiste em fazer uma avaliação socioeconômica do crime de tráfico de drogas no Estado do Acre. Especificamente, pretende-se: i realizar uma análise econômica e financeira do tráfico de drogas e, ii identificar quais são os fatores comuns entre as pessoas que migram para esta atividade criminosa. Assim, pôde-se constatar que o indivíduo considera a atividade do tráfico de drogas de grande risco, contudo, sua alta lucratividade a torna atrativa.

Dinámica migratoria... ¿hibridación cultural u homologación global?

Directory of Open Access Journals (Sweden)

Claudia Carolina Zamorano Villarreal

2014-01-01

Full Text Available Ante la consolidación del modelo de subcontratación en México asistimos a una nueva cultura laboral ¿Qué cambios ha impulsado este modelo en las prácticas de la pobla - ción y su cultura? Analizando la relación entre el modo de producción flexible de la maquila y la dinámica de migración propia a las ciudades de la frontera norte de Mé - xico, se muestra que la maquiladora respetó y aprovechó está dinámica para reducir o aumentar el número de trabajadores, según lo requiriera la producción flexible. Pero, desde mediados de los años noventa, empezó a transformar estás dinámicas y con ellas, la cultura de sus trabajadores.

Comunidades virtuales y producción de inteligencia económica y competitiva

OpenAIRE

Carvalho, Andrea Vasconcelos

2007-01-01

CARVALHO, Andréa Vasconcelos . Comunidades virtuales y producción de inteligencia económica y competitiva. Inteligencia y Seguridad: revista de análisis y prospectiva, v. 3, p. 13-45, 2007 Se defiende que las comunidades virtuales ofrecen información útil para la generación de inteligencia económica y competitiva. Así, se identifican y describen las principales aplicaciones de las comunidades virtuales para la producción de estos tipos de inteligencia. Sin embargo, no se disponen...

Femtoquímica: reacciones en tiempo real, ?`Posibles aplicaciones en Astrofísica?

Science.gov (United States)

Douhal, Abderrazzak

En esta conferencia, se mostrarán resultados de medidas en escala del femtosegundo por la primera vez obtenidos en España. Los sistemas elegidos muestran dinámicas que varían de 50 fs a centenas de picosegundo. La técnica usada (sumación de frecuencia) permite ver como ocurren las reacciones químicas y biológicas en tiempo real de reacciones. Su aplicación al estudio de las reacciones fotónicas en el espacio es evidente.

Proteômica quantitativa e metabolômica do híbrido Eucalyptus grandis x E. camaldulensis, tolerante e susceptível ao déficit hídrico

OpenAIRE

Janaina de Santana Borges

2016-01-01

O E. grandis x E. camaldulensis possui características favoráveis de adaptação à seca, conferidas pelo E. camaldulensis e qualidade da madeira para papel e celulose, conferida pelo E. grandis. Esta adaptação à seca está relacionada a fatores fisiológicos e também moleculares, expressos em sua proteoma e metaboloma, que se alteram na presença do estresse. Objetiva-se neste trabalho estudar as respostas fisiológicas, proteômicas e metabolômicas (metabólitos primários) diferencialmente expressos...

VULNERABILIDAD SOCIAL Y DINÁMICA DEMOGRÁFICA EN ARGENTINA, 2001-07

Directory of Open Access Journals (Sweden)

Leandro M. González

2009-01-01

Full Text Available En este artículo se indaga acerca de la evolución social de la República Argentina con posterioridad a la crisis socioeconómica de fines del año 2001 y considerar la persistencia de los riesgos en los años posteriores. Se analizan los principales rasgos sociales (pobreza y empleo y demográficos (fecundidad y mortalidad, para el total nacional y seis provincias de diversas regiones geográficas. La crisis socioeconómica produjo un inédito grado de empobrecimiento (55% en 2002. Las diferencias regionales se mantuvieron a lo largo del período de análisis, debido al carácter estructural que revisten. La reactivación económica del período 2003- 2007 mejoró los niveles de ingresos y empleo, aunque se registra el estancamiento en la esperanza de vida, aumentos de las tasas de mortalidad infantil y materna, e incremento continuo de la fecundidad adolescente. Se propone la hipótesis de que en la República Argentina la vulnerabilidad social es de carácter estructural y permanente, a pesar de las reducciones en las tasas de pobreza y desempleo.

AVALIAÇÃO DA ROTULAGEM, CARACTERIZAÇÃO QUÍMICA, FÍSICO-QUÍMICA E REOLÓGICA DE NÉCTARES DE UVA COMERCIALIZADOS NA CIDADE DE FORTALEZA - CE

OpenAIRE

Alessandra Pinheiro de Góes CARNEIRO; David Araujo ABREU; Denise Josino SOARES; Eveline de Alencar COSTA; Larissa Morais Ribeiro da SILVA; Lívia Carvalho BARBOSA; Paulo Henrique Machado de SOUSA; Raimundo Wilane de FIGUEIREDO

2013-01-01

No Brasil, há diferentes tipos de bebidas de frutas, dentre elas pode-se citar o suco e o néctar, que, de acordo com a legislação brasileira diferem entre si na quantidade de polpa de fruta que é adicionada em cada formulação, sendo o néctar a bebida com menor proporção de polpa de fruta. O objetivo do presente trabalho foi avaliar diferentes marcas comerciais de néctar de uva quanto às características de rotulagem, propriedades químicas, físico-químicas e reológicas. ...

Conflicto armado, variables socio-económicas y formación ciudadana: un análisis de impacto

OpenAIRE

Marieta Quintero-Mejía; Sara Victoria Alvarado; Juan Carlos Miranda

2016-01-01

En este artículo buscamos exponer los efectos que tienen las condiciones socio- económicas y el conflicto armado sobre los aprendizajes ciudadanos. Para ello, adoptamos un enfoque cuantitativo que nos permitió analizar cómo las condiciones económicas, sociales y de conflicto armado determinan el desarrollo de Competencias Ciudadanas. Lo anterior nos llevó a establecer que las variables socio-económicas tienen un impacto mayor en el desarrollo de acciones, actitudes y emociones favorables, mie...

[Machinable property of a novel dental mica glass-ceramic].

Science.gov (United States)

Chen, Ji-hua; Li, Na; Ma, Xin-pei; Zhao, Ying-hua; Sun, Xiang; Li, Guang-xin

2007-12-01

To investigate the machinability of a novel dental mica glass-ceramic and analyze the effect of heat-treatment on its ductile machinable behavior. The drilling and turning experiment were used to measure the machinabilities of the control group (feldspar ceramic: Vita Mark II) and 7 experiment groups treated with different crystallization techniques. The microstructures were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The average drilling depths in 30 s of the experimental groups ranged from (0.5 +/- 0.1) mm to (7.1 +/- 0.8) mm. There were significant differences between the control [(0.8 +/- 0.1) mm] and the experimental groups (P machining at a high velocity and cut depth. The crystal portion of this group is only about 40%. This material has a satisfactory machinability. The mechanism could be attributed to a combination of the interlocked structure of mica crystals and the low viscosity of glassy phase.

Un nuevo enfoque didáctico para acercar la Electroquímica al alumnado a través de experiencias cotidianas

OpenAIRE

Arán-Ais, Rosa M.; Busó-Rogero, Carlos; Chumillas, Sara; Climent, Víctor; Herrero, Enrique; Aldaz Riera, Antonio; Feliu, Juan M.

2013-01-01

La electroquímica es una parte importante de la química, incluida en la mayoría de los temarios de diversas ciencias experimentales. Las reacciones químicas con transferencia de electrones aparecen en numerosas situaciones de la vida cotidiana y constituyen un aspecto muy importante en las reacciones biológicas. A pesar de su importancia, la electroquímica suele ser percibida por los estudiantes con dificultad pues incluye conceptos algo abstractos, como el de potencial eléctrico, que combina...

Importancia actual de la oleoquímica en el sector industrial de tensioactivos

Directory of Open Access Journals (Sweden)

Gómez Herrera, Carlos

2009-09-01

Full Text Available Oleochemistry is an industrial sector with various applications and important developments in the field of surfactans. In this article different parts are dedicated to: A Sources of oleochemical raw materials; B Valorization of the oleochemistry in the field of surfactants; C Hydrophilic heads based on carbohydrates or proteins, D Examples of surfactants currently prepared at industrial scale, such as esters of polyols, alkylpolyglucosides, glucamides and lipoaminoacids. Collaboration between industrial sectors of surfactants and oleaginous products has evidenced various strong points. Ecological, energetic, economical and sanitary reasons will probably increase this collaboration in the future.La oleoquímica es un sector industrial con aplicaciones múltiples e importantes desarrollos en el campo de los tensioactivos. En el presente artículo se dedican apartados a: A fuentes de materias primas oleoquímicas, B valorización de la oleoquímica en el campo de los tensioactivos, C partes hidrófilas de los tensioactivos basadas en carbohidratos o en proteínas, D ejemplos de biotensioactivos actualmente preparados a escala industrial, tales como ésteres de polioles, alquilpoliglucósidos, glucamidas, ésteres de sacarosa y lipoaminoácidos. La colaboración entre los sectores industriales de tensioactivos y de productos oleaginosos ha puesto en evidencia numerosos puntos fuertes. Muy probablemente, razones energéticas, económicas, ecológicas y sanitarias harán que esta colaboración se incremente en el futuro.

Geoquímica de solos do pantanal norte, Mato Grosso

Directory of Open Access Journals (Sweden)

Elaine de Arruda Oliveira Coringa

2014-12-01

Full Text Available A caracterização e análise geoquímica de solos permitem compreender os processos de migração, dispersão e concentração de elementos químicos no perfil, embasando a correlação dos atributos deles com as classes de solos formadas, o que possibilita inferências acerca das gêneses desses solos. Esta pesquisa teve por objetivos caracterizar e interpretar a composição geoquímica total de elementos maiores e menores em classes de solos representativas do Pantanal norte, na sub-região de Barão de Melgaço, Mato Grosso, Brasil. Foram selecionados 20 perfis das principais classes de solos do Pantanal e analisadas amostras dos horizontes A e B (ou C quanto à concentração de óxidos totais por espectrometria de fluorescência de raios-X, além das caracterizações física, química e mineralógica. Os solos subdividiram-se em dois tipos geoquímicos: um composto por textura arenosa a franco-arenosa com teores relativamente elevados de SiO2 e predominância de caulinita e quartzo, com menor teor de bases e elementos-traço; e outro composto por textura mais argilosa, geoquimicamente heterogêneos e com teores significativos de minerais 2:1, Al2O3, óxidos de Fe e Mn, bases e elementos-traço.

Valoración económica de bienes ambientales.

OpenAIRE

Orrego Suaza, Sergio Alonso; Cerda Urrutia, Arcadio; Vásquez Lavín, Felipe

2011-01-01

El trabajo describe los distintos métodos de valoración económica de bienes ambientales y su utilización en estudios de impacto sobre el entorno para obtener estimaciones monetarias de los efectos negativos sobre la calidad ambiental de recursos naturales específicos.

Rutas Gastronómicas y Desarrollo local: un ensayo de conceptualización en Cataluña

OpenAIRE

Zeinab Jeambey

2016-01-01

Las rutas gastronómicas estimulan el desarrollo local sostenible de zonas agrícolas, atrayendo hacia ellas un turismo de calidad. Cataluña promociona varias rutas gastronómicas que, sin embargo, carecen de estructura y contenido coherente. En este trabajo, se consultó a expertos en el ámbito de turismo y gastronomía sobre su percepción de lo que debe ser una ruta gastronómica que contribuya al desarrollo local. Según ellos, no existen en Cataluña pautas que rijan su diseño y fun...

Software Application Profile: Opal and Mica: open-source software solutions for epidemiological data management, harmonization and dissemination.

Science.gov (United States)

Doiron, Dany; Marcon, Yannick; Fortier, Isabel; Burton, Paul; Ferretti, Vincent

2017-10-01

Improving the dissemination of information on existing epidemiological studies and facilitating the interoperability of study databases are essential to maximizing the use of resources and accelerating improvements in health. To address this, Maelstrom Research proposes Opal and Mica, two inter-operable open-source software packages providing out-of-the-box solutions for epidemiological data management, harmonization and dissemination. Opal and Mica are two standalone but inter-operable web applications written in Java, JavaScript and PHP. They provide web services and modern user interfaces to access them. Opal allows users to import, manage, annotate and harmonize study data. Mica is used to build searchable web portals disseminating study and variable metadata. When used conjointly, Mica users can securely query and retrieve summary statistics on geographically dispersed Opal servers in real-time. Integration with the DataSHIELD approach allows conducting more complex federated analyses involving statistical models. Opal and Mica are open-source and freely available at [www.obiba.org] under a General Public License (GPL) version 3, and the metadata models and taxonomies that accompany them are available under a Creative Commons licence. © The Author 2017; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association

The MICA Case Conference Program at Tewksbury Hospital, Mass.: an integrated treatment model.

Science.gov (United States)

Clodfelter, Reynolds C; Albanese, Mark J; Baker, Gregg; Domoto, Katherine; Gui, Amy L; Khantzian, Edward J

2003-01-01

This report describes the MICA (Mentally Ill Chemically Abusing) Program at the Tewksbury Hospital campus in Tewksbury, Massachusetts. Several campus facilities collaborate in the MICA Program. Through Expert Case Conferences, principles of integrated psychosocial treatment with dual diagnosis patients are demonstrated. An expert clinician focuses on the interplay between psychological pain, characterological traits, defenses, and the patient's drug of choice. Patients who have participated in the program have reported positive experiences. The staff reported that the program has resulted in facility improvement in assessment and treatment of complex dual diagnosis patients.

Premio Nobel de ciencias Económicas 1998

Directory of Open Access Journals (Sweden)

Sen Amartya

1998-12-01

Full Text Available

La Academia Real de Ciencias de Suecia ha decidido otorgar el premio Banco de Suecia 1998 en Ciencias Económicas, en Memoria de Alfred Nobel, al Profesor Amartya Sen, del Trinity College, Reino Unido, y ciudadano indio, por sus contribuciones a la economía del bienestar.

Estabilizações lombares dinâmicas Estabilizaciones lumbares dinámicas Lumbar dynamic stabilizations

Directory of Open Access Journals (Sweden)

Ivan Dias Rocha

2012-01-01

Full Text Available O funcionamento fisiológico normal da coluna depende da movimentação normal de cada unidade motora, que consiste em duas vértebras e o disco intervertebral interposto entre elas. Embora a artrodese da coluna vertebral venha sendo utilizada para o tratamento de diversas doenças da coluna, essa modalidade de tratamento acarreta a perda de movimentação dos níveis em que houve a fusão e como consequência pode sobrecarregar os níveis adjacentes podendo provocar a sua degeneração precoce. Proponentes das técnicas de estabilização dinâmicas acreditam que estas podem levar a correção dos problemas minimizando o risco de degeneração dos níveis adjacentes. Atualmente existem no mercado diversos métodos de estabilização dinâmica anteriores e posteriores. Já existem trabalhos biomecânicos que comprovam o benefício teórico de quase todos eles, porém ainda hoje, faltam ensaios clínicos que comprovem a sua utilidade e segurança por longos períodos de seguimento para o paciente. Portanto é fundamental que estes materiais sejam analisados de maneira acadêmica para que no futuro próximo possam ser utilizados em situações precisas e com segurança para os pacientes.El funcionamiento fisiológico normal de la columna depende de los movimientos normales de cada unidad motora, la cual consiste de dos vértebras y del disco intervertebral interpuesto entre ellas. Aunque la artrodesis de la columna vertebral está siendo utilizada para el tratamiento de diversas enfermedades de la columna, esa modalidad de tratamiento causa la pérdida de los movimientos en los niveles en los que hubo la fusión y, como consecuencia, puede sobrecargar los niveles adyacentes, pudiendo provocar su degeneración precoz. Los proponentes de las técnicas de estabilización dinámica creen que éstas pueden llevar a la corrección de los problemas, minimizando el riesgo de degeneración de los niveles adyacentes. Actualmente, existen en el mercado

Evaluación neuroquímica de la neuropatía óptica epidémica

OpenAIRE

González-Quevedo Monteagudo , Alina

2004-01-01

La aparición súbita en Cuba de una epidemia de neuropatía óptica en 1992,desencadenó una serie de investigaciones dirigidas a esclarecer las causas subyacentes. El presente trabajo investigó la participación del balance de aminoácidos sistémicos y en el sistema nervioso, la permeabilidad de la barrera hematoencefálica (BHE) y la neurotoxicidad del metanol en la fisiopatología de la neuropatía óptica epidémica (NOE). Se llevaron a cabo estudios en pacientes con NOE y en un modelo experimental ...

Producción electroquímica de gluconato de calcio

Directory of Open Access Journals (Sweden)

Mario Grajales T.

2010-07-01

Full Text Available Se estudió experimentalmente el efecto del potencial anódico, densidad de corriente y concentración del ion bromuro en la producción electroquímica de gluconato de calcio a partir de glucosa, usando el sistema Br2 / Br' como mediador. Las condiciones de operación de la celda electroquímica con ánodo de grafito y cátodo de acero inoxidable fueron: Potencial anódico 1.3 V (vs ESC, 46 °C, densidad de corriente 26 mA / cmS y un medio acuoso compuesto por una solución de Glucosa 0.60 M -I- NaBr 0.20 M conteniendo CaCO, en suspensión (0. 30 mol / L. La eficiencia de corriente fue del 98% y la.pureza del gluconato obtenido del 99.7 %.

Desigualdades en mortalidad relacionadas con características socioeconómicas en el departamento del Huila, Colombia, 2009-2013

Directory of Open Access Journals (Sweden)

Carlos A. Montalvo-Arce

2017-09-01

Full Text Available Objetivo: determinar las desigualdades en la mortalidad por causas específicas relacionadas con características socioeconómicas, en municipios del Huila 2009-2013. Métodos: estudio ecológico que comparó las mortalidades por Infección Respiratoria Aguda, cáncer de estómago, enfermedades hipertensivas y cerebrovasculares, accidentes de tránsito, homicidio, diabetes y mortalidad en niñez, con base en su situación socioeconómica, según las variables socioeconómicas Cobertura en Educación Media, NBI, Ruralidad, Suficiencia Económica, Valor Agregado Municipal y el Índice de Calidad del Agua en los 37 municipios del Huila. Se calcularon tasas ajustadas por edad con el método directo y medición de desigualdades confrontando las variables descritas, usando medidas basadas en rango, regresión y desproporcionalidad, usando el software Epidat 4.0. Resultados: en la mortalidad por cáncer gástrico, por enfermedades hipertensivas y en la mortalidad en niñez se identificó constante desigualdad frente a las variables socioeconómicas evaluadas, en contra de los municipios menos favorecidos. En la mortalidad por infecciones respiratorias agudas y homicidios, se observaron mayores tasas en los municipios con mejores condiciones socioeconómicas. Conclusiones: existe gran variabilidad entre las condiciones socioeconómicas de los municipios y entre las mortalidades por los eventos evaluados, observando aceptable correlación entre las diferentes medidas de desigualdades utilizadas.

Bienestar, actividad económica y cuentas nacionales. Reflexiones en torno al concepto de trabajo productivo Bienestar, actividad económica y cuentas nacionales. Reflexiones en torno al concepto de trabajo productivo

Directory of Open Access Journals (Sweden)

Sergio Cámara Izquierdo

2008-12-01

Full Text Available La medición de la actividad económica es fundamental para analizar el bienestar material de la sociedad y la dinámica económica. Sin embargo, no existe un criterio único para realizar esta medición, dadas las discrepancias en la definición del concepto de trabajo productivo entre y al interior de los distintos paradigmas económicos. Por un lado, la teoría ortodoxa concibe la producción como un proceso físico o material, como producción de bienes y servicios. Como consecuencia de la amplitud de esta definición, incurre en una serie de inconsistencias en sus planteamientos prácticos sobre la medición de la actividad económica, por lo que fracasa en su intento de servir como medida del bienestar. Además, al mezclar flujos productivos de muy distinta índole, frustra su utilidad para el análisis de la dinámica económica. Por otro lado, la teoría laboral del valor tiene un concepto de trabajo productivo coherente, a pesar de las controversias suscitadas en más de un siglo de debates, basado en una concepción de la producción históricamente específica; aunque esta limitación le impide fundamentar el análisis del bienestar, es útil para el análisis de la dinámica económica. La última parte del artículo discute las transformaciones necesarias para convertir las categorías contables ortodoxas en categorías acordes con la teoría laboral del valor. La comparación de ambas categorías para España entre 1954 y 2006 evidencia importantes diferencias en la medición del crecimiento económico y la distribución de la renta.The measurement of economic activity is central for the analysis of material welfare and economic dynamics. Nonetheless, there is not a single criterion for this measurement, given the discrepancies on the definition of the concept of productive labour among and within the various economic paradigms. On the one hand, orthodox theory conceives production as a physical or material process, as production

Biomineralización en cerámicas nanoestructuradas de aluminato de cinc

OpenAIRE

Álvarez-Pérez, M.A.; García-Hipólito, M.; de la Fuente-Hernández, J.; Suárez-Franco, J.L.; Juárez-Islas, J.A.; Álvarez-Fregoso, O.

2010-01-01

Las cerámicas nanoestructuradas en película delgada se han propuesto como una nueva opción de recubrimientos en implantes ortopédicos y dentales. Con esto en mente, se realizó un estudio para investigar el efecto de la nanotopografía en el proceso de biomineralización por medio de la preparación de películas delgadas con base en el aluminato de cinc con morfología nanométrica por el método de rocío pirolítico. Los resultados obtenidos al cultivar células osteoblásticas en las nanocerámicas, i...

Rare earth ion controlled crystallization of mica glass-ceramics

Energy Technology Data Exchange (ETDEWEB)

Garai, Mrinmoy; Karmakar, Basudeb, E-mail: basudebk@cgcri.res.in

2016-09-05

In understanding the effects of rare earth ions to control the crystallization and microstructure of alkaline boroaluminosilicate system, the CeO{sub 2}, Nd{sub 2}O{sub 3}, Sm{sub 2}O{sub 3} and Gd{sub 2}O{sub 3} doped K{sub 2}O−MgO−B{sub 2}O{sub 3}−Al{sub 2}O{sub 3}−SiO{sub 2}−F glasses were synthesized by melt-quenching at 1550 °C. Higher density (2.82–3.06 g cm{sup −3}) and thermal stability (glass phase) is experiential on addition of rare earth content, which also affects in increasing the glass transition temperature (T{sub g}) and crystallization temperature (T{sub c}). Decrease of thermal expansion in glasses with rare earth ion content is maintained by the stabilization of glass matrix owing to their large cationic field strength. A significant change in the non-isothermal DSC thermogram observed at 750–1050 °C is attributed to fluorophlogopite crystallization. Opaque glass-ceramics were prepared from such glasses by single step heat-treatment at 1050 °C; and the predominant crystalline phases are identified as fluorophlogopite mica, KMg{sub 3}(AlSi{sub 3}O{sub 10})F{sub 2} by XRD and EDX analysis. The compact glass-ceramic microstructure by the agglomeration of fluorophlogopite mica crystallites (crystal size ∼ 100–500 nm, FESEM) is achieved in attendance of rare earth ion; and such microstructure controlled the variation of density, thermal expansion and microhardness value. Higher thermal expansion (11.11–14.08 × 10{sup −6}/K at 50–800 °C and 50–900 °C) of such glass-ceramics approve that these rare earth containing glasses can be useful for high temperature vacuum sealing application with metal or solid electrolyte. The increase of Vickers microhardness (5.27–5.61 GPa) in attendance of rare earth ions is attributed to the compact crystallinity of fluorophlogopite mica glass-ceramic microstructure. - Highlights: • Synthesis of rare earth oxide doped alkaline boroaluminosilicate glasses. • Development of opaque

AVALIAÇÃO DA ROTULAGEM, CARACTERIZAÇÃO QUÍMICA, FÍSICO-QUÍMICA E REOLÓGICA DE NÉCTARES DE UVA COMERCIALIZADOS NA CIDADE DE FORTALEZA - CE

Directory of Open Access Journals (Sweden)

Alessandra Pinheiro de Góes CARNEIRO

2013-04-01

Full Text Available No Brasil, há diferentes tipos de bebidas de frutas, dentre elas pode-se citar o suco e o néctar, que, de acordo com a legislação brasileira diferem entre si na quantidade de polpa de fruta que é adicionada em cada formulação, sendo o néctar a bebida com menor proporção de polpa de fruta. O objetivo do presente trabalho foi avaliar diferentes marcas comerciais de néctar de uva quanto às características de rotulagem, propriedades químicas, físico-químicas e reológicas. O estudo foi realizado com dezesseis amostras de néctares de uva de diferentes marcas, sendo doze “tradicionais” e quatro “lights”, as quais foram obtidas em supermercados da cidade de Fortaleza, Ceará. Foram realizadas análises de pH, sólidos solúveis, acidez titulável, relação sólidos solúveis/acidez titulável, açúcares totais e redutores e ácido ascórbico. Apesar de 15% das amostras não apresentarem a denominação de venda do produto e 57% não continham o conteúdo líquido e o lote de fabricação descritos no rótulo, pode-se afirmar, que de um modo geral, os parâmetros analisados estão de acordo com o exigido pela legislação brasileira quanto à rotulagem e as características químicas e físico-químicas. Quanto às características reológicas, os néctares de uva classificam-se como fluidos newtonianos.

Los servicios móviles de información en el marco de la biblioteca académica

Directory of Open Access Journals (Sweden)

Eder Ávila Barrientos

2015-01-01

Full Text Available El objetivo de este artículo de revisión bibliográfica es analizar la integración de los servicios móviles de información en las bibliotecas académicas, para esclarecer los elementos teóricos y metodológicos inmersos en la generación de servicios bibliotecarios de información innovadores. Los servicios móviles de información en las bibliotecas académicas son utilizados por las diversas comunidades de usuarios que se presentan en este tipo de bibliotecas. Los dispositivos móviles hacen posible la consulta remota de recursos digitales de información mediante la utilización de aplicaciones móviles generadas o adaptadas por y para las bibliotecas académicas. Este fenómeno ha provocado la aparición de la biblioteca académica inteligente, caracterizada por la innovación tecnológica de sus procesos y el uso de tecnologías móviles para el apoyo de las actividades académicas y de investigación en las universidades.

Nuevos materiales didácticos para descubrir los aspectos más cotidianos de la Electroquímica

OpenAIRE

Arán-Ais, Rosa M.; Busó-Rogero, Carlos; Chumillas, Sara; Climent, Víctor; Herrero, Enrique; Aldaz Riera, Antonio; Feliu, Juan M.

2014-01-01

A pesar del amplio abanico de aplicaciones que posee la electroquímica, con importantes repercusiones en muchos aspectos de la vida cotidiana, los egresados de química de las universidades españolas poseen en general un notable desconocimiento de esta materia. Con objeto de hacer más atractivo el aprendizaje de esta parte de la química, al tiempo que se revelan algunas de sus aplicaciones menos conocidas, se han preparado nuevos materiales didácticos. En ellos se describen de manera divulgati...

Procrastinação académica a Matemática em alunos de Maputo: Estudos com adolescentes

OpenAIRE

Fulano, Celso Simão

2017-01-01

Tese de Doutoramento em Psicologia Aplicada A presente tese pretende contribuir para a literatura no domínio da procrastinação académica, analisando algumas variáveis que ajudam a explicar a procrastinação académica em matemática. Pretendemos explorar a perspetiva dos adolescentes moçambicanos em aspetos tais como: tarefas nas quais os alunos procrastinam com frequência, os antecedentes da procrastinação e as consequências da procrastinação académica percebidas pelos alunos. Al...

Berberidaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Carmen Ulloa Ulloa

2013-10-01

Full Text Available La familia Berberidaceae es reconocida en el Perú con un género, Berberis, y 32 especies (Brako & Zarucchi, 1993, mayormente arbustos. Esta familia incluye 14 endemismos. La mayoría de estas especies endémicas ocupan la región Mesoandina, entre los 2000 y 4200 m de altitud. Dos de estos taxones endémicos están representados dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Buxaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Buxaceae es reconocida en el Perú por presentar un género, Styloceras, y tres especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, todos arbustos. En este trabajo reconocemos un endemismo. Esta especie endémica se encuentra en la región Bosques Muy Húmedos Montanos, entre los 1800 y 1850 m de altitud. No está representada en el Sistema Nacional de Áreas Naturales Protegidas por el Estado.

REVISIÓN TAXONÓMICA DE LOASACEAE EN VENEZUELA

Directory of Open Access Journals (Sweden)

Noguera Eliana

2012-06-01

Full Text Available La familia Loasaceae no ha sido estudiada taxonómicamente en Venezuela, por tal razón se realizó una revisión taxonómica que permitió reconocer las especies presentes en el país y los principales caracteres de importancia taxonómica para su reconocimiento. Se examinaron 102 especímenes de Loasaceae depositados en herbarios nacionales e internacionales. En Venezuela, Loasaceae está representada por tres subfamilias (Gronovioideae, Loasoideae y Mentzelioideae, cuatros géneros (Gronovia, Klaprothia, Nasa y Mentzelia y nueve especies (Gronovia scandens L., Klaprothia fasciculata (C. Presl Poston, K. mentzelioides Kunth, Nasa lindeniana (Urb. & Gilg Weigend, N. venezuelensis (Steyerm. Weigend, N. perijensis (Weigend Weigend, N. triphylla (Juss. Weigend subsp. papaverifolia (Kunth Weigend, Mentzelia aspera L., M scabra subsp. chilensis (Gay Weigend. Se proporcionan claves para las especies presentes en el país, descripciones, ejemplares examinados, sinónimos, ilustraciones, datos de distribución geográfica y ecología, y breves comentarios morfológicos. El indumento y la ornamentación de la cubierta seminal son los principales caracteres de valor taxonómico para distinguir las especies de Loasaceae venezolanas.

Crisis global, económica, social y ambiental

Directory of Open Access Journals (Sweden)

Araceli Damián

2015-01-01

Full Text Available El presente artículo tiene la finalidad de explorar la compleja crisis del sistema capita - lista actual retomando diversos ángulos de su manifestación: económica, social y am - biental. El trabajo está dirigido a examinar las crisis del capitalismo actual a partir de la crisis inmobiliaria y financiera de 2008, que fue considerada como la más grave en el ámbito mundial después de la de 1929. Para ello se examinan, en primer término, las explicaciones que desde la teoría marxista y keynesiana se han ofrecido en torno a las crisis económicas propias del capitalismo. En segundo lugar se analizan algunas de las consecuencias de las crisis padecidas en los últimos cincuenta años, sobre todo en relación con los cambios en las relaciones de poder entre capital y trabajo; ello ha producido un deterioro en las condiciones de vida de la mayoría de la población, que se manifiesta en una creciente pobreza, desigualdad, persistencia del hambre y deterioro ambiental en el mundo.

Dinámica económica e institucionalización de la tributación directa. Trasnformaciones institucionales el caso de administración de impuestos 1920-1935

Directory of Open Access Journals (Sweden)

Oscar Rodríguez Salazar

1999-01-01

Full Text Available Las tres primeras décadas del presente siglo son el escenario de profundas transformaciones en la estructura económica del país y en el modelo institucional. El desarrollo de la economía cafetera, el acceso a la economía de crédito internacional, los cambios en la política económica, la ampliación de la infraestructura, el acelerado proceso de urbanización, los cambios demográficos, la proletarización de un contingente considerable de masas campesinas y el inicio del proceso de industrialización, marcan las mutaciones sufridas por la nación colombiana en su proceso de modernización.

"Las cooperativas: una alternativa económica y social frente a la crisis" (Cooperatives: an economic and social alternative to the crisis

Directory of Open Access Journals (Sweden)

Javier Divar Garteiz-Aurrecoa

2013-01-01

Full Text Available El Cooperativismo nació como alternativa económica y social,impulsado por la piedad religiosa y reglado bajo los principios democráticos. Lasolidaridad y la democracia económica hacen de las cooperativas sociedadesespecialmente resistentes frente a las dificultades económicas.

Effect of waste mica on transfer factors of {sup 134}Cs to spinach and lettuce; Effet de dechets de mica sur les facteurs de transfert du {sup 134}Cs a l'epinard et la laitue

Energy Technology Data Exchange (ETDEWEB)

Sreenivasa Chari, M.; Manjaiah, K.M. [Indian Agricultural Research Institute, Division of Soil Science and Agricultural Chemistry, New Delhi - 110012 (India); Sachdev, P.; Sachdev, M.S. [Indian Agricultural Research Institute, Nuclear Research Laboratory, New Delhi - 110012 (India)

2011-07-15

A greenhouse pot culture experiment was conducted to study the effect of graded levels of waste mica (0, 10, 20 and 40 g kg{sup -1}) on reducing the radiocesium uptake by spinach (Spinacia olerecea L) and lettuce (Lactuca sativa L.) grown in {sup 134}Cs-contaminated (at 37 k Bq kg{sup -1} soil) Inceptisols, Vertisols and Ultisols. The biomass yield, and potassium content and its uptake by crops have been significantly improved by waste mica application. The crops grown in Vertisols recorded higher biomass yield, and K content and its uptake as compared with Inceptisols and Ultisols. The average {sup 134}Cs transfer factor values recorded were: 0.21, 0.17 and 0.26 at the first cutting, 0.15, 0.12 and 0.28 at the second cutting and 0.07, 0.05 and 0.23 at the third cutting from Inceptisols, Vertisols and Ultisols, respectively. Waste mica significantly suppressed radiocesium uptake, the effect being more pronounced at 40 g mica kg{sup -1} soil. There exists an inverse relationship between the {sup 134}Cs transfer factors with plant potassium content and also the K uptake by the crops. (authors)

Thermal properties and crystallization of lithium–mica glass and glass-ceramics

International Nuclear Information System (INIS)

Nia, A. Faeghi

2013-01-01

Highlights: • Two groups of Li–mica glass-ceramics, have been compared. • By controlling the glass composition, crystalline lepidolite was obtained. • The T p of Li–mica was through the previous virgilite and eucryptite phase. - Abstract: The purpose of this study was the synthesis of two groups of Li–mica glass-ceramics denoted by lepidolite (Al 2.5 F 2 KLi 1.5 O 10 Si 3 ) and Li-phlogopite (LiMg 3 AlSi 3 O 10 F 2 ). The studied system was SiO 2 –Al 2 O 3 –MgO–K 2 O–Li 2 O. A total of 3 compositions were prepared. Bulk casted glasses and sintered glass-ceramics of Li-phlogopite and lepidolite systems, were prepared. Eucryptite and virgilite were two prior phases of lepidolite and Li-phlogopite crystallization. It was shown that the obtained glass-ceramics have lower TEC than corresponding glasses. Sinterability of lepidolite glass-ceramic was shown that improved by increasing the Al 2 O 3 content in glass composition. TEC and microhardness values were α = 6.08 × 10 −6 /°C, 755 ± 11.1, α = 7.86 × 10 −6 /°C, 739 ± 7.4 and α = 5.05 × 10 −6 /°C, 658 ± 6.2 HV for Li-lep, Klep1 and Klep2 glasses, respectively

La química y la lengua española en el s. XIX

Directory of Open Access Journals (Sweden)

Garriga, Cecilio

2003-12-01

Full Text Available The lexis of chemistry registered an important change from the final quarter of the C.18. The translation of the Nueva nomenclatura química («New Chemical Nomenclature» brought in its wake the arrival of new terms to the Spanish language. Bearing in mind the latest data provided from the history of science, this study explains and exemplifies the tension within the lexical system created by the arrival of the new terms.

El léxico de la química registra un cambio importante a partir del último cuarto del siglo XVIII. La traducción de la Nueva nomenclatura química conlleva la llegada de los nuevos términos al español. En este estudio se explican y ejemplifican las tensiones que la llegada de nuevos términos provoca en el sistema léxico. Todo ello teniendo en cuenta los últimos datos proporcionados desde la historia de la ciencia.

Determinación astronómica de la Desviación de la Vertical

Science.gov (United States)

Pacheco, A. M.; Podestá, R. C.

A partir de las coordenadas astronómicas de Latitud y Longitud determinadas en la falla geológica de Nikizanga ubicada en las serranías de Pie de Palo, y, en base a un Punto Datum de referencia, se desarrolla la metodología para la determinación de la Desviación de la Vertical, que comprende la reducción de las observaciones astronómicas, transformaciones de coordenadas, aplicación de correcciones y el cálculo definitivo de los valores angulares de la Vertical. Estos estudios se iniciaron a sugerencia del Servicio Internacional de Latitud, International Polar Motion Service (IPMS), con el objeto de obtener en determinados puntos de la Tierra la Desviación de la Vertical y su variación, dentro de la nueva disciplina denominada Astrogeodinámica, con la idea de correlacionar estas variaciones con la predicción de grandes sismos.

Sorderas neurosensoriales no sindrómicas: Análisis de la herencia en 10 familias

Directory of Open Access Journals (Sweden)

Ibis Menéndez

1998-06-01

Full Text Available Se reportan los árboles genealógicos de 10 probandos afectados con sorderas neurosensoriales no sindrómicas de aparición familiar. El análisis genético practicado permitió reconocer la clara segregación de un único gen de sordera en 7 familias (3 autosómicas recesivas, 2 autosómicas dominantes, 1 ligada al cromosoma X, 1 con herencia mitocondrial. En las 3 familias restantes resultó difícil el análisis y se propuso la herencia recesiva como la más probable, sobre la base, fundamentalmente, de las características de la pérdida auditiva (congénita, bilateral, severa o profunda. En general las sorderas autosómicas recesivas fueron las más frecuentes. Se corrobora que estos estudios suelen ser complicados por la gran heterogeneidad que pueden presentar a todos los niveles las sorderas neurosensoriales no sindrómicas.The pedigress of 10 examiness affected with non syndrome neurosensorial deafness of familial appearance were erported. The genetical analysis made allowed to recognize the clear segregation of a sale gene of deafness in 7 families (3 recessive autosomal, 2 dominant autosomal, 1 linked to cromosome X, and 1 with mitochondrial heredity. In the other 3 hamilies the analysis was difficult and the recessive heredity was suggested as the most probable, based mainly on the characteristics of auditive loss (congenital, bilateral, severe or deep. In general, the recessive autosomal deafness was the most common. It was corroborated that these studies are usually complicated due to the great heterogeneity that the non syndromic neurosensorial deafness may present at all levels.

Molecular beam epitaxy of graphene on mica

International Nuclear Information System (INIS)

Lippert, G.; Dabrowski, J.; Yamamoto, Y.; Mehr, W.; Lupina, G.; Herziger, F.; Maultzsch, J.; Baringhaus, J.; Tegenkamp, C.; Lemme, M.C.

2012-01-01

Realization of graphene devices is often hindered by the fact that the known layer growth methods do not meet the requirements of the device fabrication in silicon mainstream technology. For example, the relatively straightforward method of decomposition of hexagonal SiC is not CMOS-compatible due to the high-thermal budget it requires [Moon et al., IEEE Electron Device Lett. 31, 260 (2010)]. Techniques based on layer transfer are restricted because of the uncertainty of residual metal contaminants, particles, and structural defects. Of interest is thus a method that would allow one to grow a graphene film directly in the device area where graphene is needed. Production of large area graphene is not necessarily required in this case, but high quality of the film and metal-free growth on an insulating substrate at temperatures below 1000 C are important requirements. We demonstrate direct growth of defect-free graphene on insulators at moderate temperatures by molecular beam epitaxy. The quality of the graphene was probed by high-resolution Raman spectroscopy, indicating a negligible density of defects. The spectra are compared with those from graphene flakes mechanically exfoliated from native graphite onto mica. These results are combined with insights from density functional theory calculations. A model of graphene growth on mica and similar substrates is proposed. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

LA RACIONALIDAD ECONÓMICA EN NUEVA PERSPECTIVA

Directory of Open Access Journals (Sweden)

Jorge Arturo Chaves

2002-08-01

Full Text Available Las amenazas a la vida en el planeta, los hechos que han “asaltado al dogma económico” (Daly y Cobb, 1993 tienen mucho que ver con una doble toma de conciencia en la sociedad contemporánea. La primera, sobre lo restringida y esterilizante que resulta una visión economicista para enfrentar los problemas que más preocupan al ser humano hoy: las heridas infligidas al ecosistema, el aumento de la pobreza y la desigualdad, y el crecimiento desproporcionado de la actividad humana en relación a las posibilidades de la biosfera.La segunda, implicada en la anterior, la de darse cuenta que esa limitación está asociada al concepto de suyo estrecho y parcial de racionalidad económica. Enfrentamos aquí el problema del reduccionismo transmitido en el discurso y en la práctica misma de la disciplina económica que, sin embargo, no es exclusivo de ésta ni es atribuible sólo a deficiencias internas de los profesionales que la practican. Existe toda una larga tradición dentro de la cual se ha ido reduciendo de manera progresiva el concepto de razón humana y se ha ido produciendo ese concepto estrecho de racionalidad del que ahora la humanidad realiza esfuerzos por librarse.

Elites y Hasbur entre las coyunturas económicas del siglo XVIII en Centroamérica

OpenAIRE

Wortman, Miles

2002-01-01

Resumen Estudia la dinámica económica del siglo XVII en Centroamérica, desde el punto de vista de la producción y el comercio. Aborda el problema de la existencia o no de una depresión generalizada en la región durante ese período, y lo contrasta con el siglo anterior y posterior

Tema 1. Introducción a la geoquímica de las aguas subterráneas

OpenAIRE

Boluda Botella, Nuria

2010-01-01

Tema 1. Introducción a la geoquímica de las aguas subterráneas. Se presenta una introducción de la asignatura. Se manejan conceptos sobre calidad de aguas, muestreo y análisis químico de las aguas, procesos de contaminación, con énfasis en la geoquímica de la intrusión marina.

Possible mechanism of adhesion in a mica supported phospholipid bilayer

International Nuclear Information System (INIS)

Pertsin, Alexander; Grunze, Michael

2014-01-01

Phospholipid bilayers supported on hydrophilic solids like silica and mica play a substantial role in fundamental studies and technological applications of phospholipid membranes. In both cases the molecular mechanism of adhesion between the bilayer and the support is of primary interest. Since the possibilities of experimental methods in this specific area are rather limited, the methods of computer simulation acquire great importance. In this paper we use the grand canonical Monte Carlo technique and an atomistic force field to simulate the behavior of a mica supported phospholipid bilayer in pure water as a function of the distance between the bilayer and the support. The simulation reveals a possible adhesion mechanism, where the adhesion is due to individual lipid molecules that protrude from the bilayer and form widely spaced links with the support. Simultaneously, the bilayer remains separated from the bilayer by a thin water interlayer which maintains the bilayer fluidity

The growth of sodium rough films on mica (0001) as determined by Helium Atom Scattering

DEFF Research Database (Denmark)

Gerlach, Rolf; Balzer, Frank; Rubahn, Horst-Günter

2001-01-01

, which is addressed to Na atoms that fill cleavage-induced holes in the mica surface. It provides a convenient means of calibrating the coverage of the surface. With increasing surface coverage Na clusters are formed on the mica surface. A broad angular distribution of the scattered Helium intensity......Elastic helium atom scattering (HAS) and linear optical extinction measurements are used to investigate the growth of sodium (Na) films on mica substrates in the surface temperature range between 90 and 300 K. At half a monolayer (ML) surface coverage we observe a maximum of scattered He intensity...... is observed with a coverage-independent angular width above eight monolayers coverage. From simultaneous optical extinction measurements we deduce that the clusters are oblate with a ratio of semiaxes perpendicular and parallel to the surface plane between 0.23 and 0.165....

EXPANSIÓN ECONÓMICA Y CONFLICTO MAPUCHE. LA ARAUCANÍA, 1900-1940

Directory of Open Access Journals (Sweden)

JORGE PINTO RODRÍGUEZ

2011-06-01

Full Text Available Este artículo examina la expansión económica que se produjo en la Araucanía durante la primera parte del siglo XX y el impacto que tuvo esta expansión en la sociedad mapuche. La fundación de ciudades, los nuevos circuitos económicos que se generan al interior de la región y las nuevas conexiones de la economía regional con mercados externos, provocaron una expansión económica que favoreció a las comunidades mapuches que encontraron en aquellos mercados un espacio en el cual colocar su producción. Esta etapa (1890-1920/30 corresponde a la fase exitosa del acoplamiento de la región al Estado; sin embargo, estuvo acompañado también de una serie de abusos al indígena, entre los cuales el más grave fue el robo de sus tierras. La fase exitosa fue seguida por una pérdida del dinamismo económico que afectó de un modo particular a los pequeños y medianos campesinos, sobre todo después de los años 30. Las comunidades mapuches sintieron los efectos de esta situación, debiendo algunos de sus miembros emigrar hacia Concepción, Santiago o Valparaíso en busca de mejores horizontes. Fue, por lo tanto, una época de luces y sombras para la región y su población mapuche. La expansión económica no se pudo sostener y los abusos cometidos contra el pueblo mapuche debilitaron sus defensas para enfrentar la contracción económica que se produjo a partir de 1930.

Heterogeneidades y condiciones de trabajo de los docentes universitarios en la Universidad de Buenos Aires: Un estudio comparado de las Facultades de Farmacia y Bioquímica, y Ciencias Económicas

OpenAIRE

RIKAP, Cecilia

2016-01-01

El presente artículo analiza las condiciones de trabajo de la docencia universitaria de grado a partir del caso de la Universidad de Buenos Aires (UBA). En particular, se profundizará sobre las facultades de Farmacia y Bioquímica (FFyB) y Ciencias Económicas (FCE) en tanto conforman, respectivamente, ejemplos representativos de las tradiciones de investigación y profesional, que conviven en la UBA. Se abordarán las siguientes características: percepción de salario, estabilidad en el empleo, r...

La farmacogenómica en medicina

OpenAIRE

Carlos Isaza; Juan C. Sepúlveda-Arias; Julieta Henao

2009-01-01

Introducción: La farmacogenómica estudia la forma como las variaciones del genoma influyen en la respuesta a medicamentos. Su principal valor médico consiste en: i) la identificación de individuos en quienes se puede predecir si un fármaco será eficaz y a qué dosis o, por el contrario, si el fármaco se debe evitar por alto riesgo de toxicidad o porque el paciente nunca responderá a él; ii) identificar blancos moleculares susceptibles de ser intervenidos por fármacos.Objetivo: Revisar y sistem...

Eletroquímica de solos modais e de sua matéria orgânica em ambientes tropicais

Directory of Open Access Journals (Sweden)

Marihus Altoé Baldotto

2014-12-01

Full Text Available A química do solo vem estudando o comportamento da fração mineral dos solos tropicais intemperizados, incluindo a eletroquímica, o desenvolvimento de cargas e o fenômeno de adsorção. Por causa do amplo espectro a ser coberto no entendimento do comportamento da fração mineral, somado às dificuldades metodológicas, o estudo da complexa fração orgânica dos solos foi relativamente menos desenvolvido. A atual proposta revisita os primeiros trabalhos referentes à química de solos tropicais, buscando relacioná-los com dados de eletroquímica dos estoques de carbono do solo. O objetivo deste trabalho foi revisar aspectos de eletroquímica de solos, determinar e relacionar os pontos de carga zero, por diferentes métodos, os potenciais da dupla camada elétricae a eletroquímica do húmus de solos modais brasileiros, em uma sequência típica de intemperismo, visando a gerar informações para o seu manejo e conservação. Os métodos de estimativa dos ponto de carga zero dos solos apresentam resultados variados, mas com a mesma tendência entre os solos. Há predomínio de cargas negativas em ambas as camadas dos solos estudados. As cargas negativas dos coloides estão diretamente associadas à disponibilidade de elétrons do húmus e ambas diminuem com o estádio de intemperismo do solo.

Hepatitis isquémica Ischemic hepatitis

Directory of Open Access Journals (Sweden)

Marcos Amuchástegui (h

2006-10-01

Full Text Available La hepatitis isquémica es una complicación sumamente infrecuente de cirugía cardiovascular. Las biopsias muestran necrosis centrolobulillar. El término de "hepatitis" fue propuesto debido al aumento de transaminasas similar a aquellas de origen infeccioso, e "isquémica" por falla en la perfusión hepática. Posteriormente se definió el término de hepatitis isquémica como cuadro de elevación aguda y reversible (dentro de las 72 horas de transaminasas de hasta 20 veces el valor normal, asociado a trastornos en la perfusión hepática, luego de haber excluido otras causas de hepatitis aguda o daño hepatocelular. Se describe el caso de un paciente de 53 años que consulta por dolor epigástrico de 12 h de evolución sin fiebre, náuseas ni vómitos, resistente a la medicación. Tenía antecedentes inmediatos de reemplazo de válvula aórtica, y estaba anticoagulado. Evolucionó con shock y fallo multiorgánico. El examen evidenció marcada ictericia y signos de taponamiento pericárdico, asociado a un aumento considerable de enzimas hepáticas. Un ecocardiograma informó signos de taponamiento cardíaco y ausencia de disección aórtica. Se decidió pericardiocentesis, extrayéndose 970 cc. de líquido sanguinolento, y hemodiálisis, con notable mejoría de su estado hemodinámico. Los valores enzimáticos disminuyeron. Los marcadores virales fueron negativos.Ischemic hepatitis is an uncommon cardiovascular surgery complication. Hepatic biopsies show centrolobulillar necrosis. The term "hepatitis" was proposed because of a raise in hepatic enzymes similar with infectious disease, and "ischemic" because of failure in hepatic perfusion. Ischemic hepatitis was then defined as an acute and reversible elevation of hepatic enzymes (within 72 h, associated with disturbance in hepatic perfusion after excluding other causes of acute hepatitis. A 53 year-old male presented complaining of a 12 h epigastric pain, without nausea or vomiting, resistant

Dinámica exportadora de las empresas born global en Colombia

Directory of Open Access Journals (Sweden)

Diana Marcela Escandón Barbosa

2015-11-01

Full Text Available Este artículo pretende analizar las condiciones principales del mercado exportador de las empresas born global en el caso colombiano, teniendo en cuenta los principales factores del entorno que determinan su dinámica exportadora. Se utiliza la base de datos GEM Colombia del año 2011, para analizar 297 empresas born global colombianas, mediante un análisis descriptivo y la estimación de un modelo de conglomerados bietápico. Los resultados muestran que los cambios tecnológicos, las características sectoriales y la intensidad competitiva son factores determinantes de la dinámica exportadora de las empresas born global en Colombia, y se concluye que los empresarios se adaptan al mercado internacional mejorando continuamente sus productos y procesos.

Terapia fotodinâmica em carcinoma basocelular periocular: relato de caso

Directory of Open Access Journals (Sweden)

Rachel Camargo Carneiro

2012-12-01

Full Text Available Os autores descrevem a aplicação de terapia fotodinâmica com cloridrato de aminolevulinato de metila (Metivix® em uma paciente com carcinoma basocelular padrão misto (nodular e infiltrativo em pálpebra inferior de olho direito. Os efeitos colaterais sobre o olho foram avaliados semanalmente. Foi submetida à biòpsia incisional com punch de 2 mm para controle de cura após 12 semanas de tratamento. O anátomopatológico revelou ausência de neoplasia. O tratamento padrão ouro reconhecido mundialmente é a exérese da lesão, porém a terapia fotodinâmica com cloridrato de aminolevulinato de metila (MAL surge como uma opção terapêutica à cirurgia.

Crystallization Kinetics and Characterization of Nanostructure Mica Glass-Ceramics with Optical Transparency

Directory of Open Access Journals (Sweden)

P. Alizadeh

2014-01-01

Full Text Available Transparent glasses in a system of Li2O-MgO-SiO2-Al2O3-Fchemical constituents were prepared by melt quenching method. In the fabrication of nanocrystal glass-ceramics, controlled nucleation and subsequent crystal growth were necessary to avoid loss of transparency. It was therefore important to understand thermal properties and crystallization kinetics of the glass ceramics. The crystallization behavior of the prepared glass was investigated by DTA, XRD and SEM. By crystallization heat-treatment, various crystalline phases, microstructure and transmittance were obtained. The sellaite was first precipitated as the nuclei before the crystallization of mica and then mica nanocrystals were precipitated with average size of

RACIONALIDADE ECONÔMICA, TRABALHO E ECOLOGIA EM ANDRÉ GORZ

Directory of Open Access Journals (Sweden)

André Langer

Full Text Available O presente artigo tem por objetivo apresentar a análise crítica de André Gorz sobre o trabalho e a ecologia política a partir da centralidade que o conceito de racionalidade econômica no capitalismo adquire em seu pensamento. Para ele, a extensão ilimitada da racionalidade econômica ao trabalho e à natureza é considerada sem futuro do ponto de vista da sociedade. Gorz reconhece a íntima relação entre a crítica do capitalismo e a tarefa da ecologia política. Outro aspecto presente em sua obra, menos explorado, é a relação entre trabalho e crise ecológica. O capitalismo apropria-se do trabalho ou emprego não apenas para os seus interesses, mas também os transforma em instrumentos de destruição da natureza. Este paper objetiva também, fiel ao espírito do próprio Gorz, embora de maneira sucinta, indicar alguns horizontes alternativos.

Procrastinación general y académica en una muestra de estudiantes de secundaria de Lima metropolitana

OpenAIRE

Álvarez-Blas, Óscar Ricardo; Universidad de Lima (Perú)

2010-01-01

Se estudió la presencia de la procrastinación general y académica en un grupo de estudiantes de secundaria (N = 235) de ambos géneros pertenecientes a colegios no estatales de Lima metropolitana, para lo cual se utilizó la Escala de Procrastinación General y Académica (Busko, 1998). Sobre la base del análisis de los resultados se encontró que la procrastinación académica era mayor que la general, y no existían diferencias significativas según rol genérico y el grado de estudios. Se adjunta el...

La ingeniería electroquímica aplicadas a la reducción de cetonas ciclícas

OpenAIRE

Nieto Lemus, Luis

2011-01-01

La electroquímica en medios no acuosos es una de las áreas que más desarrollo tiene en la actualidad, ya que permite establecer un vínculo muy interesante entre las técnicas experimentales de la química orgánica tradicional y los procesos de transferencia de carga. Entre los campos más promisorios podemos mencionar le electrosíntesis, la electrocatálisis y el estudio de reacciones electroquímicas de compuestos orgánicos como un elemento de apoyo en la determinación de mecanismos de reacció...

A IMPORTÂNCIA DA SOCIEDADE BRASILEIRA DE QUÍMICA NA PÓS-GRADUAÇÃO EM QUÍMICA NO BRASIL

Directory of Open Access Journals (Sweden)

Aldo J. G. Zarbin

Full Text Available The role of the different actions headed by the Brazilian Chemical Society (SBQ for the development of the Graduate Programs in Chemistry in Brazil is highlighted herein. Specifically, the importance of the SBQ journals, such as the Quimica Nova (QN, Journal of the Brazilian Chemical Society (JBCS and Revista Brasileira de Química (RVQ as vehicles to disseminate the knowledge produced by the different graduate programs in chemistry is demonstrated.

Análisis del enfoque de historia y filosofía de la ciencia en libros de texto de química : el caso de la estructura atómica

OpenAIRE

Farías Camero, Diana María

2013-01-01

Este trabajo analiza desde el enfoque de historia y filosofía de las ciencias (HFC) la forma como se presenta el tema de estructura atómica en cinco libros de texto (LT) de los cursos de química de primer año de la Universidad de Barcelona. En el análisis se aplicó un marco metodológico que exploró la posibilidad de emplear diferentes metodologías (heterogéneas entre sí) para lograr una explicación más acertada del tema de estudio. Los resultados mostraron que la mayoría de los textos present...

Trabajo cooperativo y adquisición de competencias en bioquímica y biología molecular

OpenAIRE

Rodríguez García, Francisco David; Gutiérrez de Diego, Juana

2011-01-01

Memoria ID-008.Ayudas de la Universidad de Salamanca para la innovación docente, curso 2010-2011. La Bioquímica y la Biología Molecular son materias esenciales en la formación de un químico. Ambas disciplinas se rigen por los mismos principios de la Química, la Física y las Matemáticas. Su peculiaridad estriba en el contexto en el que los fenómenos físico-químicos tienen lugar: la vida. Así pues, la Bioquímica estudia la vida en términos físicos y químicos e intenta desentrañar los meca...

Meaurement of the target single-spin asymmetry in quasi-elastic region from the reaction {sup 3}He{up_arrow}(e,e')

Energy Technology Data Exchange (ETDEWEB)

Zhang, Yawei [Rutgers

2013-10-01

A measurement of the inclusive target single-spin asymmetry has been performed using the quasi-elastic {sup 3}He{up_arrow}(e,e') reaction with a vertically polarized {sup 3}He target at Q{sup 2} values of 0.13, 0.46 and 0.97 GeV{sup 2}. This asymmetry vanishes under the one photon exchange assumption. But the interference between two-photon exchange and one-photon exchange gives rise to an imaginary amplitude, so that a non-zero A{sub y} is allowed. The experiment, conducted in Hall A of Jefferson Laboratory in 2009, used two independent spectrometers to simultaneously measure the target single-spin asymmetry. Using the effective polarization approximation, the neutron single-spin asymmetries were extracted from the measured {sup 3}He asymmetries. The measurement is to establish a non-vanishing A{sub y}. Non-zero asymmetries were observed at all Q{sup 2} points, and the overall precision is an order of magnitude improved over the existing proton data. The data provide new constraints on Generalized Parton Distribution (GPD) models and new information on the dynamics of the two-photon exchange process.

Search for B_c^± arrow J/ψ μ^± X Decays in pbarp Collisions at √s=1.8 TeV

Science.gov (United States)

Singh, Prem

1997-04-01

The B_c^± meson, a bound state of charm and bottom quarks, is expected to have several narrow mass states below the B--D open flavor threshold. We describe a search for the weak decays of the B_c^± produced in a 110 pb-1 sample of √s= 1.8 TeV proton-antiproton collisions in the CDF detector at the Fermilab Tevatron. A high branching ratio of B_c^± to J/ψ decays permits an effective trigger on these events. The search is conducted through the decay B_c^± arrow J/ψ μ^± X. Supported by U.S. DOE under Contract No. DE-FG02-91ER40646. We thank the Fermilab staff and the technical staffs of the participating institutions for their vital contributions. This work was supported by the U.S. Department of Energy and National Science Foundation; the Italian Istituto Nazionale di Fisica Nucleare; the Ministry of Education, Science and Culture of Japan; the Natural Sciences and Engineering Research Council of Canada; the National Science Council of the Republic of China; and the A. P. Sloan Foundation.

de la química

Directory of Open Access Journals (Sweden)

Gregorio Jiménez-Valverde

2006-01-01

Full Text Available En la presente comunicación se detalla una innovadora experiencia llevada a cabo durante los cursos 2001-02 y 2002-03 consistente en el uso del BSCW, un entorno telemático para el trabajo cooperativo, en el Ciclo Formativo de Grado Superior de Química Ambiental. En el artículo se detallan las principales características del entorno, cómo fue aplicado y los resultados que se obtuvieron, presentados en páginas web creadas por los propios estudiantes sobre diferentes aspectos de metales en aguas. El alumnado, a través de una encuesta, respaldó esta experiencia y mostró una actitud muy positiva en la creación de materiales hipermedia.

Role of NKG2D-Expressing NK Cells and sMICA in Immune Surveillance of Advanced Lung Cancer

Directory of Open Access Journals (Sweden)

Jing LIANG

2009-01-01

Full Text Available Background and objective NKG2D-expressing NK cells and soluble major histocompatibility complex class Ⅰ-related chain A (sMICA is one of aroused general interests in tumor research area recently. The aimof the study is to investigate the levels of NKG2D-expressing NK cells and sMICA in peripheral blood of advanced lung cancer which are remarkably related to clinical significance and analyse the role of NKG2D-expressing NK cells and sMICA in immune surveillance. Methods Flow cytometry was used to determine the percentage of NKG2D-expressing NK cells, T cell subsets, NK cells, and ELISA was used to mesure the levels of sMICA in peripheral blood of 115 advanced lung cancer patients and 50 healthy controls. Results Compared with control group, the levels of sMICA、CD8+T cells, NK cells increased, while the levels of NKG2D-expressing NK cells, CD3+ T cells, CD4+ T cells, CD4+ T/CD8+ T in experimental group decreased. NKG2D-expressing NK cells had a perfect negative correlation with sMICA (r =-0.319, P <0.05. NKG2D-expressing NK cells had positive correlation with CD4+ T cells, CD4+ T/CD8+ T and negative correlationwith CD8+ T cells (P <0.05, sMICA had negative correlation with CD4+ T cells, CD4+ T/CD8+ T and positive correlation with CD8+ T cells (P <0.05, they had no significant correlation with CD3+ T cells, NK cells respectively (P <0.05. Conclusion Accumulation of sMICA in serum may lead to the down-modulation of NKG2D-expressing NK which has been proposed to be a novel mechanism used by cancer cells to evade the tumor immunosurveillance. They may be potential indicators investigating immune functions and helpful in the evaluation of their happening and proceeding.

Investigación económica y laboral del mercado turístico de la provincia de Santa Cruz

OpenAIRE

Natalia Soledad Villanueva; Daniel Alberto Schinelli

2014-01-01

Este proyecto de investigación se propone realizar un diagnóstico actualizado sobre diversos sectores productivos en la dinámica socio-económica de la provincia de Santa Cruz. Particularmente el turismo se presenta como una actividad emergente y de gran importancia en la economía provincial. Sin embargo se advierte la inexistencia de información actualizada y sistematizada que englobe el funcionamiento del sector turístico, su relevancia económica y laboral, como también estudios de zonificac...

Caracterización bioquímica de microorganismos rizosféricos de plantas de vainilla con potencial como biofertilizantes.

OpenAIRE

Claudia Álvarez-López; Walter Osorio-Vega; María Claudia Díez-Gómez; Mauricio Marín-Montoya

2014-01-01

Caracterización bioquímica de microorganismos rizosféricos de plantas de vainilla con potencial como biofertilizantes. El objetivo de este trabajo fue evaluar la actividad bioquímica in vitro con potencial biofertilizante en microorganismos rizosféricos de plantas de vainilla. Se realizó una confirmación fenotípica de la identidad taxonómica de los microorganismos más eficientes en las diferentes pruebas. Los aislamientos se llevaron a cabo durante el año 2011 en cultivos de vainilla ...

Culturas académicas: entre reinvención y contrabando

Directory of Open Access Journals (Sweden)

Kathya Araujo

2015-03-01

Full Text Available Sobre la base del análisis de una historia personal de desplazamiento entre academias (peruana y chilena, y la reinvención y el contrabando que toda migración supone, este artículo argumenta de qué manera frente a las nuevas modalidades de evaluación (los rankings, la búsqueda de isomorfismo de las estructuras argumentativas y las formas lingüísticas o incluso la ficción de sociologías globales, se mantienen vivas culturas académicas particulares. En este marco, la reflexión se organiza mostrando que detrás de la singularidad de los estilos intelectuales, formas de sociabilidad profesionales e incluso formas lingüísticas de cada una de ellas, lo que se revela es la manera como cada cultura académica local responde desde tradiciones diversas a desafíos político sociales distintos y con ello su rol de compromiso público y crítico.

Pesquisa e desenvolvimento em cerâmicas eletro-eletrônicas no IPEN

Directory of Open Access Journals (Sweden)

Muccillo R.

1999-01-01

Full Text Available O Grupo de Cerâmicas Eletro-eletrônicas do IPEN desenvolve trabalhos de pesquisa em materiais cerâmicos avançados para utilização em dispositivos sensores de espécies químicas e em células de combustíveis a eletrólitos sólidos. As principais áreas de atuação do grupo são em 1 síntese, processamento e caracterização elétrica de materiais cerâmicos, 2 estudo de correlação microestrutura-propriedades elétricas de materiais cerâmicos, 3 projeto, desenvolvimento, montagem e testes de sensores eletroquímicos de espécies químicas. Os principais materiais estudados são condutores iônicos (à base de ZrO2, ThO2 e outros, protônicos (à base de BaCeO3, varistores à base de SnO2, supercondutores cerâmicos de alta temperatura crítica (das famílias Y-Ba-Cu-O e Bi-Sr-Ca-Cu-O e compósitos de matriz cerâmica (dos tipos isolante em matriz condutora iônica e condutor iônico em matriz supercondutora. A infra-estrutura experimental dispõe de analisador de impedância, difratômetro de raios X, equipamento de análise térmica simultânea, fornos para sinterização e laboratório químico. O trabalho de pesquisa do Grupo é financiado por projetos FAPESP e PRONEX.

Dinâmica populacional da mariposa oriental em pomares de pessegueiro e ameixeira

Directory of Open Access Journals (Sweden)

Hickel Eduardo Rodrigues

2003-01-01

Full Text Available O objetivo deste trabalho foi estudar a dinâmica populacional da mariposa oriental [Grapholita molesta (Busk] em pomares de pessegueiro e ameixeira. Os adultos foram monitorados em dois pomares de pessegueiro e um de ameixeira por cinco anos. Séries temporais equivalentes de temperaturas máximas e mínimas foram correlacionadas aos dados de flutuação populacional para se aferir a correspondência entre a ocorrência da praga e as flutuações de temperatura. A análise de Fourier das séries temporais das armadilhas de coleta de mariposas revelou dinâmicas cíclicas, com período principal médio de 53,91 semanas. Um período menor médio, de 7,45 semanas, também ficou evidente e se aproxima do tempo médio de geração do inseto. A análise do espectro de potência das séries temporais, com e sem periodicidade, revelou que a dinâmica populacional de G. molesta possui um componente regular, caracterizado pelos períodos observados, e outro componente irregular, reminiscente de ruído 1/f, caracterizado pelas variações de amplitude, aparentemente irregulares, na ocorrência do inseto. A combinação desses dois componentes ocasiona um processo com domínio de baixas freqüências, próprio das dinâmicas periódicas ruidosas. Os ciclos de aparecimento da praga ocorrem em fase com os ciclos de flutuação de temperaturas máximas e mínimas.

Aspleniaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available Esta familia es reconocida en el Perú con un solo género, Asplenium y más de 65 especies (Tryon & Stolze, 1993; Smith et al., 2005. Aspleniaceae está representada en un amplio rango de ambientes; sin embargo, las dos especies endémicas reconocidas ocupan principalmente los bosques de las regiones del Bosque Húmedo Montano y Premontano, entre los 700 y 2500 m de altitud. Solamente, una de estas especies cuenta con poblaciones en un área protegida.

Costaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Costaceae es reconocida en el Perú por presentar tres géneros y 26 especies (Brako & Zarucchi, 1993, todas ellas hierbas. En este trabajo reconocemos tres endemismos en dos géneros. Un género, Monocostus, es endémico. Las especies endémicas ocupan los bosques de la llanura amazónica y bosques premontanos húmedos, entre los 300 y 800 m de altitud. Ninguno de estos taxones se encuentra representado en un área natural protegida.

Strength and strain anisotropy of olkiluoto mica gneiss

International Nuclear Information System (INIS)

Hakala, M.; Kuula, H.; Hudson, J.

2006-10-01

An anisotropy in the elastic moduli values of intact rock with a ratio of more than 1.3∼1.5 has been reported to have an effect on the calculated magnitudes and orientations of the in situ principal stress components as measured by the overcoring method. Work related to the on-going site investigation for a deep radioactive waste repository at the Olkiluoto site in Western Finland has shown that the migmatic mica gneiss is anisotropic which could therefore affect the interpretation of overcoring stress measurement results. This paper includes a summary of the theory of anisotropy concerning the intact rock moduli via the strain compliance matrix, a description of the core sample testing methods, and interpretation of results for the migmatic mica gneiss from two site investigation boreholes. In this case study, 19 specimens were tested and the results showed a modulus anisotropy of about 1.4. Because such anisotropy is high enough to produce significant errors in the estimation of the in situ principal stresses, it is recommended to take this into account in the interpretation of the stress measurement results, both in the context of the current work in Finland and in other projects where similar anisotropy is encountered. (orig.)

Capillary condensation of water between mica surfaces above and below zero-effect of surface ions.

Science.gov (United States)

Nowak, Dominika; Christenson, Hugo K

2009-09-01

We have studied the capillary condensation of water from saturated vapor below 0 degrees C in the annular wedge-pore formed around two mica surfaces in contact in a surface force apparatus. The condensed water remains liquid down to at least -9 degrees C, and the measured condensate size is close to the predictions of a recent model for the dependence of the interfacial curvature of supercooled capillary condensates on temperature and surface tension. The small deviation observed may be accounted for by assuming that solute as K(2)CO(3) from the mica-condensate interface dissolves in the condensates and gives rise to an additional depression of the freezing point apart from that caused by the interface curvature. By contrast, measurements of the interface curvature at relative vapor pressures of 0.95-0.99 at 20 degrees C confirm a significantly larger deviation from the Kelvin equation. The magnitude of the deviation is in remarkable agreement with that calculated from the results of an earlier study of capillary condensation of water from a nonpolar liquid, also at T = 20 degrees C. Evidently, additional solute from the surrounding mica surface migrates into the condensates at room temperature. We conclude that the surface diffusion of ions on mica is much slower at subzero temperatures than at room temperature.

Esclerosis sistémica complicada con síncope y bloqueo AV completo

Directory of Open Access Journals (Sweden)

Francisco Femenía

2010-10-01

Full Text Available La esclerosis sistémica es una compleja enfermedad que afecta el tejido conectivo, el sistema vascular y el sistema inmunológico, y se caracteriza por fibrosis cutánea y de órganos viscerales. Los bloqueos de rama y los hemibloqueos se presentan en el 25 a 75% de los casos y constituyen predictores independientes de mortalidad. Los bloqueos auriculoventriculares de segundo o tercer grado son muy raros. Presentamos el caso de una mujer de 47 años de edad, con diagnóstico de esclerosis sistémica, quien presenta episodio sincopal secundario a bloqueo auriculoventricular completo con necesidad de implante de marcapasos definitivo.

Contribuciones bibliográficas de la Facultad de Farmacia y Bioquímica

OpenAIRE

Bonilla Rivera, Pablo E.

2014-01-01

La contribución bibliográfica de la facultad de Farmacia y Bioquímica de San Marcos es muy importante, pero tal vez poco conocida en los claustros sanmarquinos. Por ello, a partir de este número, "Ciencia e Investigación" incluirá las listas de las contribuciones hechas por los docentes de la facultad y por los exalumnos a través de sus tesis de título y de grados académicos. La contribución bibliográfica de la facultad de Farmacia y Bioquímica de San Marcos es muy importante, pero tal vez...

Muhlenbergia monandra (Poaceae: Eragrostideae, nueva especie anual endémica del Perú

Directory of Open Access Journals (Sweden)

J. José Alegría Olivera

2001-01-01

Full Text Available Se describe e ilustra Muhlenbergia monandra, endémica de Perú. La nueva especie se caracteriza por sus glumas mayores que el antecio, por tener inflorescencias espiciformes y las flores cleistógamas con un estambre. La anatomía foliar se describe e ilustra y se detallan sus caracteres diferenciales. Se incluyen observaciones sobre la epidermis de la lemma y las glumas realizadas con el Microscopio Electrónico de Barrido. Se discute la posición taxonómica de la nueva entidad y las diferencias con las especies anuales relacionadas que habitan en América del Sur

Insuficiencia dinámica, crecimiento y desempleo en México, 1974-2012

OpenAIRE

Vargas, Blanca L. Avendaño; Hernández, Ignacio Perrotini

2015-01-01

El artículo presenta una reformulación de la hipótesis de insuficiencia dinámica de Prebisch (1970), analiza la teoría dinámica de Harrod (1939), la ley Kaldor-Verdoorn (Kaldor, 1966; 1967) y la teoría del crecimiento endógeno de Thirlwall (1969; 2000)Thirlwall and León-Ledesma, 2000. A posteriori estudiamos los determinantes del crecimiento económico y del desempleo en México durante el periodo 1974-2012. Con base en el análisis empírico, sostenemos que una baja tasa de acumulación genera una...

Conflicto armado, variables socio-económicas y formación ciudadana: un análisis de impacto

Directory of Open Access Journals (Sweden)

Marieta Quintero-Mejía

2016-02-01

Full Text Available En este artículo buscamos exponer los efectos que tienen las condiciones socio- económicas y el conflicto armado sobre los aprendizajes ciudadanos. Para ello, adoptamos un enfoque cuantitativo que nos permitió analizar cómo las condiciones económicas, sociales y de conflicto armado determinan el desarrollo de Competencias Ciudadanas. Lo anterior nos llevó a establecer que las variables socio-económicas tienen un impacto mayor en el desarrollo de acciones, actitudes y emociones favorables, mientras que las condiciones de conflicto armado están más asociadas a la construcción de ambientes democráticos

Desarrollo de algoritmos bioinformáticos para estudios de genómica funcional: aplicaciones en cáncer

OpenAIRE

Fontanillo Fontanillo, Celia

2014-01-01

[ES]La presente Tesis Doctoral se enmarca en las áreas de conocimiento de la Bioinformática y Biología Computacional y también de la Genómica Funcional y Genómica del Cáncer. El objetivo fundamental de la Genómica Funcional es entender cómo funciona el genoma en su conjunto mediante el análisis de la actividad de todos sus genes y de los múltiples factores que regulan o influyen la expresión de los mismos, así como otras entidades biomoleculares relacionadas. La recolección sistemática de inf...

Isquemia microvascular miocárdica, un compromiso asintomático en esclerosis sistémica

OpenAIRE

Rausch, Gretel

2011-01-01

La Esclerosis Sistémica (ES) es una enfermedad autoinmune y multisistémica, cuya afectación básica es una lesión vascular generalizada, que produce isquemia y fibrosis secundaria del tejido comprometido. El compromiso miocárdico primario (sin compromiso pulmonar o renal), es frecuente, y un grave factor de riesgo de muerte. Junto con la fibrosis pulmonar y la hipertensión pulmonar, es una de las principales causas de mortalidad. Facultad de Ciencias Médicas

Implementación de la carrera académica como medio de integración del NSPT a la Universidad

Directory of Open Access Journals (Sweden)

Noemi Susana Geromini

2013-12-01

Full Text Available http://dx.doi.org/10.5007/1983-4535.2013v6n4p92   Con el fin de mejorar la calidad académica de su cuerpo docente, el Instituto Nacional Superior del Profesorado Técnico -INSPT-, como Institución de Educación Superior  no Universitaria, considera necesaria la planificación de estrategias que permitan generar espacios de pertenencia a sus docentes, que les otorguen estabilidad laboral y posibilidades de proyección, mediante el establecimiento de reglas claras e imparciales que protejan a la comunidad académica. La calidad académica se logra por medio de una clara definición de las características esperadas de los docentes y la excelencia se fomenta con procesos de evaluación continuos de todas las activida-des de la vida académica: enseñanza, investigación, extensión y gestión. La Carrera Académica, sistema que establece ingreso, permanencia y promoción de los docentes, resulta ser el recurso más adecuado para estimular la mejora continua de la tarea docente y lograr la excelencia académica, haciendo posible la integración de una institución no universitaria al sistema universitario. Mediante un exhaustivo análisis de la idiosincrasia de la comunidad educativa del INSPT, y aten-diendo a las características esperables de sus docentes, el Instituto procura adaptarse al régimen docente universitario vigente en la Universidad Tecnológica Nacional  -UTN. Para lograr este objetivo, se han analizado el Estatuto Universitario, la Ordenanza 1182 del Consejo Superior y se ha elaborado un documento que, por un lado, fundamenta la necesidad de adecuar el régimen de ingreso, permanencia y promoción docente del INSPT a la Carrera Académica de la Universidad, y por otro, propone los pasos a seguir para su implementación, con el convencimiento de que su aplicación redundará en una continua mejora de la calidad académica del Instituto. El presente trabajo tiene como objetivos, por un lado, fundamentar y describir el proceso de

La crisis actual y la culpabilidad de la teoría macroeconómica

Directory of Open Access Journals (Sweden)

Paul Ormerod

2010-06-01

Full Text Available Las ideas de la macroeconomía moderna proporcionaron la justificación intelectual de las políticas económicas de los últimos diez o quince años. La crisis actual ha puesto en cuestión estas ideas. El paradigma dominante en la teoría macroeconómica de los últimos treinta años ha sido el de los agentes racionales que forman racionalmente sus expectativas acerca del futuro y toman decisiones óptimas. El objetivo es estudiar la forma en que estos agentes se ocupan del riesgo y la incertidumbre, origen de los problemas de la disciplina económica, de la economía y de la crisis financiera. La macroeconomía moderna tiene responsabilidad en la crisis financiera, pues impone su base intelectual a un mundo en que opera en situaciones de riesgo que se subestiman de manera sistemática y lleva a que las situaciones de auténtica incertidumbre no sean reconocidas claramente.

Aumentando la realidad química

Directory of Open Access Journals (Sweden)

Mª Luisa Roqueta Buj

2017-08-01

Full Text Available El uso de nuevas tecnologías como la Realidad Aumentada en la enseñanza de la Química permite manejar información virtual y asociarla a elementos de la vida real. Se accede a la misma a través de un dispositivo tecnológico con un software específico. Esta herramienta tecnológica recibe el nombre de Realidad Aumentada y permite añadir contenido digital a nuestro mundo real aumentando la percepción que tenemos del mismo. Nos permite incorporar contenido en forma de texto, imagen, audio o vídeo.

Evolución Dinámica de Cúmulos Estelares Abiertos

Science.gov (United States)

de La Fuente Marcos, R.

Las estrellas que observamos no se formaron aisladamente, sino que lo hicieron en grupos o cúmulos. Estos sistemas estelares recibenel nombre de cúmulos estelares abiertos o galácticos cuando están constituidos por estrellas de la Población I. Los cúmulos abiertos se localizan preferentemente en el plano galáctico, y en muchos de ellos está teniendo lugar aún una activa formación estelar. El propósito principal de esta tesis doctoral es el estudio de la evolución dinámica de estos sistemas estelares por medio de simulaciones numéricas y de la comparación de sus resultados con datos observacionales. Con este fin se analizan los efectos que, sobre la dinámica de los cúmulos, ejercen varios fenómenos de interés astrofísico tales como el campo gravitatorio galáctico, la pérdida de masa causada por la evolución estelar y la presencia de binarias primordiales. En este trabajo se presentan los resultados de más de un centenar de modelos de cúmulos, con poblaciones comprendidas en el intervalo [100, 10.000] estrellas, calculados con NBODY5, un programa estándar en el campo de la Dinámica Estelar Experimental. De los mismos se deduce que el mecanismo principal que rige la dinámica de los cúmulos abiertos es la evolución estelar de su distribución de masas, encontrándose un comportamiento diferencial fuertemente dependiente de la población inicial del cúmulo. Los mecanismos responsables de la desintegración de los cúmulos abiertos son analizados en detalle, proponiéndose un modelo analítico que ajusta razonablemente los resultados de las simulaciones. Además, y con el fin de explicar el elevado número de sistemas múltiples observados en cúmulos abiertos, se estudian los efectos que, sobre los mismos, ejerce la presencia de una cierta fracción de binarias primordiales. El papel de las binarias tambiín depende de la riqueza del cúmulo y sus efectos se interrelacionan con aquellos debidos a la evolución estelar. Por último, se

The effects of retrograde reactions and of diffusion on 39Ar-40Ar ages of micas

DEFF Research Database (Denmark)

Allaz, Julien; Engi, Martin; Berger, Alfons

2011-01-01

Effects of metamorphic reactions occurring during decompression were explored to understand their influence on 39Ar-40Ar ages of micas. Monometamorphic metasediments from the Lepontine Alps (Switzerland) were studied. Collected samples reached lower amphibolite facies during the Barrovian....... XRD-data indicated that some mineral separates prepared for Ar-Ar stepwise heating analysis were monomineralic, whereas others were composed of two white micas (muscovite with paragonite or margarite), or biotite and chlorite. In monomineralic samples 37Ar/39Ar and 38Ar/39Ar (proportional to Ca....../K and Cl/K ratios) did not change and the resulting ages can be interpreted unambiguously. In mineral separates containing two white micas, Ca/K and Cl/K ratios were variable, reflecting non-simultaneous laboratory degassing of the two heterochemical Ar-reservoirs. These ratios were used to identify each...

Buddlejaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Buddlejaceae es reconocida en el Perú por presentar dos géneros y 16 especies (Norman, 2000; Ulloa Ulloa et al., 2004, principalmente arbustos. En este trabajo reconocemos dos especies endémicas en el género Buddleja. Estos taxones endémicos se encuentran en las regiones Mesoandina, Puna Húmeda y Seca y Páramo, entre los 2650 y 3900 m de altitud. Una de estas dos especies se encuentra representada dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Tropaeolaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available Esta es la familia de la «mashua». La familia Tropaeolaceae es reconocida en el Perú por presentar un género, Tropaeolum, y 24 especies (Brako & Zarucchi, 1993, todas herbáceas y bejucos. En este trabajo reconocemos 10 especies endémicas, las cuales se encuentran principalmente en las regiones Bosques Muy Húmedos Montanos y Mesoandina, entre los 1800 y 3200 m de altitud. Una especie, aparentemente, se encuentra representada dentro del Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Abundancias químicas de ψ Octantis

Science.gov (United States)

Medina, M. C.; Pintado, O. I.

Se determinan las abundancias químicas de ψ Oct usando espectros obtenidos con EBASIM en CASLEO. Los valores iniciales de temperatura efectiva y gravedad superficial se calculan con la fotometría uvbyβ. Esta estrella fue estudiada por Pintado y Adelman (1996) usando espectros REOSC y Adelman y otros (1993), este último basado en espectros echelle obtenidos con el Telescopio Anglo Australiano. Comparamos nuestros resultados con los de los trabajos anteriormente mencionados, pudiéndose realizar una evaluación de la calidad de los espectros EBASIM.

Burmanniaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Burmanniaceae es reconocida en el Perú por presentar ocho géneros y 16 especies (Brako & Zarucchi, 1993, principalmente hierbas saprófitas. En este trabajo reconocemos un endemismo en el genero Burmannia. Esta especie endémica posee un amplio grado de adaptación ambiental, habiéndosele localizado en las vertientes occidentales, valles interandinos, páramos y bosques montanos orientales, entre los 1200 y 4100 m de altitud. Esta especie se encuentra representada en un área natural protegida.

Sistema financiero y productividad económica

OpenAIRE

Antonio Torrero Mañas

2012-01-01

La crisis financiera que estalla en el otoño del 2007 ha inducido a reflexionar sobre los efectos económicos de las finanzas. De manera muy especial se están analizando las consecuencias de la expansión de mercados, instituciones y volumen de transacciones financieras. Las finanzas se han extendido en todas las facetas de la vida económica, con las familias como protagonista esencial. La actuación de Gobiernos y Bancos Centrales ha tenido muy en cuenta la experiencia de la Gran Depresión, ...

física y química

Directory of Open Access Journals (Sweden)

Cristina Díez-Rodríguez

2005-01-01

Full Text Available La experiencia que se plantea a continuación recoge el desarrollo de una estrategia de comunicación entre un grupo de alumnos de Bachillerato y su profesora de Física y Química, basada en el uso de Internet como medio de expresión y comunicación. Se trata de una experiencia piloto, diseñada como paso previo a la integración definitiva de varias herramientas de comunicación en el desarrollo del próximo curso escolar

Historia Experimental de la Química

Directory of Open Access Journals (Sweden)

José Antonio Chamizo

2009-10-01

Full Text Available A partir de una discusión de la importancia de la experimentación en la enseñanza de las ciencias y el valor que la didáctica le da a la historia y la filosofía, se propone abordar la enseñanza experimental de la historia de la química a partir de la postura historiográfica recurrente empleando diagramas heurísticos. Lo anterior a través de diez experimentos elegidos por su valor didáctico y tecnocientífico.

Flacourtiaceae endémicas del Perú

Directory of Open Access Journals (Sweden)

Blanca León

2013-10-01

Full Text Available La familia Flacourtiaceae es reconocida en el Perú por presentar 19 géneros y 65 especies (Brako & Zarucchi, 1993; Ulloa Ulloa et al., 2004, mayormente arbustos y árboles. En este trabajo reconocemos tres especies endémicas en dos géneros, las cuales ocupan la región de los Bosques Muy Húmedos Montanos, entre los 2300 y 3600 m de altitud. Solamente una de estas especies se encuentra representada en el Sistema Nacional de Áreas Naturales Protegidas por el Estado.

Incidencia de chirridos con el uso de cerámica en cerámica Biolox Delta en artroplastía de cadera. [Incidence of squeaking using third-generation biolox® delta ceramic on ceramic bearing surfaces.

Directory of Open Access Journals (Sweden)

Gerardo Zanotti

2014-06-01

Full Text Available In­tro­duc­ción: La superficie cerámica-cerámica causa complicaciones, como la fractura y la generación de ruidos articulares (squeaking. Este estudio muestra nuestra experiencia con la utilización del compuesto de matriz alúmina (cerámica Delta. Materiales­ y ­Métodos: Se evaluaron, en forma retrospectiva, 109 caderas, 97 pacientes, con edad promedio de 49 años (rango 17-77. Ciento dos de estas caderas fueron cirugías primarias, mientras que 7 fueron revisiones. Todos los componentes acetabulares fueron Pinnacle® (DePuy Orthopaedics, Warsaw, Indiana, EE.UU. La cerámica utilizada en todos los casos fue BIOLOX® Delta (Ceram Tec AG, Plochingen, Alemania. Resultados: El seguimiento fue de 37 meses (rango 24- 50. Se realizó la medición radiográfica de la anteversión, por el método de Ackland (rango 1°-35°, la inclinación (rango 22°-67°, el diámetro acetabular (rango 48-62 mm, el tamaño de la cabeza femoral (88: 36 mm y 21: 28 mm y la lateralización antes de la cirugía y después de ella. Se evaluó a todos los pacientes con el puntaje de Harris, los resultados fueron, en su mayoría, muy buenos y algunos, buenos. Las complicaciones fueron: una luxación (0,91%, una subluxación protésica (0,91%, una infección aguda (0,91%, una fractura periprotésica (0,91%, una rotura del inserto de cerámica (0,91%. Ningún paciente refirió ruidos o una cadera chirriante. Conclusión: En esta serie, no se reportaron episodios de chirridos, pese a la gran variación en la anteversión y la inclinación del componente acetabular. Creemos que la composición y el diseño de la cerámica de tercera genera- ción determinarían un menor índice de chirridos que las de segunda generación.

Desenvolvimento e caracterização de cerâmicas para fabricação de próteses dentárias

OpenAIRE

RAMOS FILHO, Fernando Bezerra

2008-01-01

Atualmente, as qualidades dos produtos e do processamento têm vital importância em quase todos os setores econômicos em nossa sociedade. O desenvolvimento e caracterização de cerâmica para fabricação de próteses dentária vêm sendo buscados através de vários trabalhos ao longo da história. As cerâmicas odontológicas podem consistir principalmente em vidros, porcelanas, cerâmicas vítreas ou estruturas cristalinas. Elas possuem propriedades químicas, mecânicas, físicas e térmic...