2,957 research outputs found
Tax Credits Response to Tax Enforcement: Evidence from a Quasi-Experiment in Chile
Diesel in Chile receives a different tax treatment depending on its use. If diesel is used in industrial activities the diesel tax paid can be used as a credit against VAT and if diesel is used in freight or public transportation (basically trucks and buses) a fraction of gasoline taxes paid can be used as a credit against VAT. As a result of this different tax treatment firms have incentives to use “tax exempted” diesel in activities requiring “non tax exempted” diesel. This price wedge generates and opportunity for tax evasion. In this paper we analyze the impact of a tax enforcement program implemented by the Chilean IRS, where letters requiring information about diesel tax credits were sent to around 200 firms in 2003. Using different empirical strategies to consider the non-randomness of the selection of firms, we find that firms receiving a letter decreased their diesel tax credits by 16%.Chile. Fondo Nacional de Desarrollo Científico y Tecnológico 111054
Electric charge in the field of a magnetic event in three-dimensional spacetime
We analyze the motion of an electric charge in the field of a magnetically
charged event in three-dimensional spacetime. We start by exhibiting a first
integral of the equations of motion in terms of the three conserved components
of the spacetime angular momentum, and then proceed numerically. After crossing
the light cone of the event, an electric charge initially at rest starts
rotating and slowing down. There are two lengths appearing in the problem: (i)
the characteristic length , where and are the
electric charge and mass of the particle, and is the magnetic charge of the
event; and (ii) the spacetime impact parameter . For , after a time of order , the particle makes sharply a quarter of a
turn and comes to rest at the same spatial position at which the event happened
in the past. This jump is the main signature of the presence of the magnetic
event as felt by an electric charge. A derivation of the expression for the
angular momentum that uses Noether's theorem in the magnetic representation is
given in the Appendix.Comment: Version to appear in Phys. Rev.
Repurposing of terconazole as an anti Trypanosoma cruzi agent
Trypanosoma cruzi is the causative agent of Chagas disease, a parasitic infection endemic in Latin America. Currently there are no effective treatments for the chronic phase of the disease, when most patients are diagnosed, therefore the development of new drugs is a priority area. Several triazoles, used as fungicides, exhibit trypanocidal activity both in vitro and in vivo. The mechanism of action of such drugs, both in fungi and in T. cruzi, relies in the inhibition of ergosterol biosynthesis affecting the cell viability and growth. Among them, terconazole was the first triazole antifungal drug for human use. In this work, the trypanocidal activity of terconazole was evaluated using in vitro assays. In epimastigotes of two parasites strains from different discrete typing units (Y and Dm28c) the calculated IC50 were 25.7 μM and 21.9 μM, respectively. In trypomastigotes and amastigotes (the clinically relevant life-stages of T. cruzi) a higher drug susceptibility was observed with IC50 values of 4.6 μM and 5.9 μM, respectively. Finally, the molecular docking simulations suggest that terconazole inhibits the T. cruzi cytochrome P450 14-α-demethylase, interacting in a similar way that other triazole drugs. Drug repurposing to Chagas disease treatment is one of the recommended approach according to the criterion of international health organizations for their application in neglected diseases.Fil: Reigada, Chantal. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Martínez Sayé, Melisa Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Valera Vera, Edward Augusto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Miranda, Mariana Reneé. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; ArgentinaFil: Pereira, Claudio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentin
Reducing fall risk with combined motor and cognitive training in elderly fallers
Background. Falling is a major clinical problem in elderly people, demanding effective solutions. At present, the only effective intervention is motor training of balance and strength. Executive function-based training (EFt) might be effective at preventing falls according to evidence showing a relationship between executive functions and gait abnormalities. The aim was to assess the effectiveness of a motor and a cognitive treatment developed within the EU co-funded project I-DONT-FALL. Methods. In a sample of 481 elderly people at risk of falls recruited in this multicenter randomised controlled trial, the effectiveness of a motor treatment (pure motor or mixed with EFt) of 24 one-hour sessions delivered through an i-Walker with a non-motor treatment (pure EFt or control condition) was evaluated. Similarly, a 24 one-hour session cognitive treatment (pure EFt or mixed with motor training), delivered through a touch-screen computer was compared with a non-cognitive treatment (pure motor or control condition). Results. Motor treatment, particularly when mixed with EFt, reduced significantly fear of falling (F(1,478) = 6.786, p = 0.009) although to a limited extent (ES -0.25) restricted to the period after intervention. Conclusions. This study suggests the effectiveness of motor treatment empowered by EFt in reducing fear of falling.Peer ReviewedPostprint (published version
Desnutrición en niños de 2 a 5 años que asisten al Centro de Salud nº 66 El Mirador
En el centro de salud Nº 66 “El Mirador" Rivadavia, se observó, un grupo etario, (niños de 2-5 años), con un marcado déficit nutricional. Esto marcó un interés que lleva a investigar más profundo para determinar los factores que afectan a este grupo en particular.
Los objetivos de este trabajo son: identificar factores que inciden en la desnutrición en niños de 2 a 5 años que asisten al centro de salud N° 66, analizar los recursos socio económico de la familia responsable de los niños, conocer hábitos alimenticios de la familia, determinar nivel cultural de los adultos responsables y establecer parámetros de grado de nutrición.Fil: Sosa, Marta Gladys. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería..Fil: Martínez, Claudio. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería..Fil: Gómez, Patricia. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería.
Memory loss in Alzheimer's disease: are the alterations in the UPR network involved in the cognitive impairment?
Artículo de publicación ISIThis work was funded by the Alzheimer Disease Association, Millennium Institute no. P09-015-F, FONDECYT no. 1100176, ACT1109; CONICYT grant USA2013-0003, ECOS-CONICYTC13S02 and FONDEF D11I1007 (Claudio Hetz), Doctoral Fellow supported by CONICYT (Gabriela Martínez) and FONDECYT grant no. 3140466 (Claudia Duran-Aniotz)
Fully bio-based aromatic–aliphatic copolyesters: poly(butylene furandicarboxylate-co-succinate)s obtained by ring opening polymerization
Poly(butylene 2,5-furandicarboxylate-co-succinate) copolyesters (coPBFxSy) have been synthesized by
ring opening polymerization (ROP). Cyclic butylene 2,5-furandicarboxylate and butylene succinate
oligomer mixtures, to be used as monomers for ROP, were prepared by high dilution condensation
and enzymatic cyclization reactions, respectively. Two different catalytic systems, tin dioctanoate and
supported Candida antarctica lipase B (CALB), were used for polymerization. Thus two series of copolyesters
covering the whole range of compositions were prepared and their properties comparatively
examined. In both cases, random copolyesters with compositions close to those used in their respective
feeds were obtained. The influence of composition on reaction kinetics with respect to time and
temperature was evaluated for the two series. Chemically catalyzed ROP rendered copolyesters with Mw
in the ~50 000–65 000 g mol-1 range, whereas values between 15 000 and 45 000 g mol-1 were attained
when the ROP reaction was assisted by CALB. The thermal behavior of coPBFxSy obtained by ROP was
similar to that reported for such copolymers prepared by melt polycondensation. They all start to decompose
above 300 °C and display melting enthalpy and temperatures that decrease with copolymerization,
attaining minimum values when the comonomer contents are approximate to balance. On the
contrary, the glass-transition temperature increased almost linearly with the content of butylene furandicarboxylate
units, covering the whole range of values between those of the two parent homopolyesters.
Small deviations in thermal properties observed between the two series could be attributed to their differences
in molecular weights. Hydrolytic and enzymatic degradation studies revealed that coPBFxSy
became more degradable with increasing content of succinic units, whereas the homopolyester PBF
remained practically unaffected when incubated under similar conditions.Peer ReviewedPostprint (author's final draft
Limit cycles of a perturbation of a polynomial Hamiltonian systems of degree 4 symmetric with respect to the origin
We study the number of limit cycles bifurcating from the origin of a Hamiltonian system of degree 4. We prove, using the averaging theory of order 7, that there are quartic polynomial systems close these Hamiltonian systems having 3 limit cycles
Epidemiología de las consultas respiratorias de adultos en Santiago de Chile desde 2003 a 2008
Background: Respiratory diseases are the third cause of death, and the second cause of hospitalization among people aged 65 years or more in Chile. Aim: To analyze the distribution of consultations due to respiratory diseases among adults living in Metropolitan Santiago. Material and Methods: A daily registry of all consultations of patients older than 15 years old in seven public primary care centers, was carried out between January 2003 and December 2008. Consultations were classified as having non-respiratory or respiratory causes. The latter were broke down in upper or lower respiratory diseases, pneumonia, chronic obstructive pulmonary disease (COPD) and asthma. Results: A total of 1,170,941 consultations were registered and 19% were due to respiratory diseases. Of these, 46% were due to upper respiratory diseases, 31% due to lower respiratory diseases, 8% due to COPD, 6% due to pneumonia, 5% due to asthma and 4% due to other respiratory causes. Pneumonia and COPD were more frequent among consultants older than 65 years. Conclusions: Consultations due to respiratory diseases are approximately one fifth of all primary care consultations. Older people often have more chronic and severe diseases.
Key words: Adult; Epidemiology; Morbidity; Respiratory tract diseases
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