Optimization of reactive extraction of C1–C4 aliphatic monocarboxylic acids from aqueous solutions: modeling solvation effect with extended-LSER, A-UNIFAC and SPR Senol, Aynur; Çehreli, Süheyla; Özparlak, Nur; Andreatta, Alfonsina Ester This paper studies reactive extraction of formic (FA), acetic (AA), propionic (PA) and butyric (BA) acids from aqueous solutions by tri-n-butyl amine/diluent, with particular focus on proper optimization and modeling of extraction equilibria. The uptake capacities of amine/diluent and diluent alone approximate the following order: oleyl alcohol > octyl acetate > diisobutyl ketone and BA > PA > AA ≈ FA. An intrinsic optimization structure has been applied to the description of optimum extraction field of relevant systems, based on analyzing the variation profiles of separation ratio R and synergistic enhancement SE factors through the derivative variation method. We present new solvation molecular models extended-linear solvation energy relation (e-LSER), SPR1 and SPR2 (solvation probability relation), and an extension to group-contribution approach A-UNIFAC (Association-UNIFAC). A-UNIFAC predicts phase equilibria using new group interaction parameters regressed from vapor-liquid equilibrium data. The e-LSER model involves eight descriptors used for expressing solvent effects. By performing SPR1 and SPR2, we are able to scale up the probability range and activation energy of solvation effect. The strength of acid-amine association is calculated with chemodel. e-LSER, A-UNIFAC, SPR and chemodel simulate accurately the observed performance with average deviations inferior to 4.8%, 24.1%, 0.8% and 16.2%, respectively.

Ultracompact states of native proteins Grille Coronel, Leandro; Acierno, Juan Pablo; Ermacora, Mario Roberto A statistical analysis of circa 20,000 X-ray structures evidenced the effects of temperature of data collection on protein intramolecular distances and degree of compaction. Identical chains with data collected at cryogenic ultralow temperatures (≤160 K) showed a radius of gyration (Rg) significantly smaller than at moderate temperatures (≥240 K). Furthermore, the analysis revealed the existence of structures with a Rg significantly smaller than expected for cryogenic temperatures. In these ultracompact cases, the unusually small Rg could not be specifically attributed to any experimental parameter or crystal features. Ultracompaction involves most atoms and results in their displacement toward the center of the molecule. Ultracompact structures on average have significantly shorter van der Waals and hydrogen bonds than expected for ultralow temperature structures. In addition, the number of van der Waals contacts was larger in ultracompact than in ultralow temperature structures. The structure of these ultracompact states was analyzed in detail and the implication and possible causes of the phenomenon are discussed.

Expression of the mRNA stability regulator Tristetraprolin is required for lactation maintenance in the mouse mammary gland Goddio, Maria Victoria; Gattelli, Albana; Tocci, Johanna Melisa; Perez Cuervo, Lourdes; Stedile, Micaela Nadia; Stumpo, Deborah; Hynes, Nancy; Blackshear, Perry; Meiss, Roberto P.; Kordon, Edith Claudia Tristetraprolin (TTP), an mRNA-binding protein that negatively controls levels of inflammatory factors, is highly expressed in the lactating mouse mammary gland. To determine the biological relevance of this expression profile, we developed bi-transgenic mice in which this protein is specifically down-regulated in the secretory mammary epithelium in the secretory mammary epithelium during lactation. Our data show that TTP conditional KO mice produced underweight litters, possibly due to massive mammary cell death induced during lactation without the requirement of additional stimuli. This effect was linked to overexpression of inflammatory cytokines, activation of STAT3 and down-regulation of AKT phosphorylation. Importantly, blocking TNFa activity in the lactating conditional TTP KO mice inhibited cell death and similar effects were observed when this treatment was applied to wild-type animals during 48 h after weaning. Therefore, our results demonstrate that during lactation TTP wards off early involution by preventing the increase of local inflammatory factors. In addition, our data reveal the relevance of locally secreted TNFa for triggering programmed cell death after weaning.

Differences in seed dormancy associated with the domestication of Cucurbita maxima: Elucidation of some mechanisms behind this response Martinez, Analia Beatriz Luján; Lema, Veronica Soledad; Capparelli, Aylen; Lopez Anido, Fernando Sebastian; Benech-Arnold, Roberto Luis; Bartoli, Carlos Guillermo This work presents the results of physiological studies developed to understand modifications linked to the reduction of seed dormancy provoked by domestication processes. The experiments performed compared wild and domesticated Cucurbita subspecies and their hybrids developed by reciprocal crossings. Seeds of two accessions of the wild subspecies presented dormancy, but it was largely reduced in seeds from the domesticated genotype, and partially reverted in hybrids, especially in those obtained when the domesticated genotype was used as the mother plant. In addition, naked embryos of all subspecies did not display dormancy when incubation was performed at 28°C, but embryo germination was progressively reduced only in the wild genotype under decreasing incubation temperatures (22 and 16°C). In the embryos, abscisic acid (ABA) concentrations were similar in both domesticated and wild subspecies, whereas in the seed coat, it was threefold higher in the wild subspecies. The naked embryos from the wild subspecies were far more responsive to ABA than those from the domesticated subspecies. These results indicate that dormancy in the wild subspecies is imposed by the seed coat tissues and that this effect is mediated by their high ABA content and the sensitivity of the embryos to ABA. These physiological aspects were apparently removed by domestication along with the temperature-dependent response for germination.

Layered double hydroxide nanoparticles customization by polyelectrolyte adsorption: mechanism and effect on particle aggregation Vasti, Cecilia; Borgiallo, Andres; Giacomelli, Carla Eugenia; Rojas Delgado, Ricardo Adsorption of polyelectrolytes (PEs) is a common strategy for stabilizing nanoparticles and customizing their properties. Although scarcely explored for layered double hydroxide nanoparticles (LDH-NPs), it can be used to increase their functionality in pharmaceutical and biomedical applications, among others. In this work, LDH-NPs intercalated with chloride, ibuprofen and ketoprofen were synthesized and modified with carboxylate containing PEs with different structures and physicochemical properties. The PEs adsorption mechanism on LDH-NPs and its effect on the aggregation of the obtained hybrids were studied by zeta potential and hydrodynamic diameter determinations on chloride intercalated LDH-NPs dispersions in the presence of polyacrylate (PA) at different concentrations. PA adsorption behavior was compared to that of citrate anion to contrast the adsorption mechanism of PEs and anions. Afterwards, the study was extended to other PEs (alginate and carbomer) as well as to drug intercalated LDH-NPs. PA adsorbed at the surface of LDH-NPs with high affinity: at low concentrations, PA was irreversibly adsorbed due to the positive structural charge of LDH-NPs and the flexible and negatively charged structure of PA. This high affinity caused a particle charge inversion, which results in negatively charged LDH-NPs stabilized by both electrostatic interactions and steric hindrance. Due to their structure, alginate and carbomer showed a lower affinity and, consequently, a lower capacity to produce LDH-NPs disaggregation. Finally, PEs adsorption allowed enhancing the disaggregation and modifying the interfacial properties of both ibuprofen and ketoprofen intercalated LDH-NPs producing only a small release of the drug loading.

Effects of oxidation on the plasmonic properties of aluminum nanoclusters Douglas Gallardo, Oscar Alejandro; Soldano, Germán; Mariscal, Marcelo; Sanchez, Cristian Gabriel The scouting of alternative plasmonic materials able to enhance and extend the optical properties of noble metal nanostructures is on the rise. Aluminum is endowed with a set of interesting properties which turn it into an attractive plasmonic material. Here we present the optical and electronic features of different aluminum nanostructures stemming from a multilevel computational study. Molecular Dynamics (MD) simulations using a reactive force field (ReaxFF), carefully validated with Density Functional Theory (DFT), were employed to mimic the oxidation of icosahedral aluminum nanoclusters. Resulting structures with different oxidation degrees were then studied through the Time-Dependent Density Functional Tight Binding (TD-DFTB) method. A similar approach was used in aluminum nanoclusters with a disordered structure to study how the loss of crystallinity affects the optical properties. To the best of our knowledge, this is the first report that addresses this issue from the fully atomistic time-dependent approach by means of two different and powerful simulation tools able to describe quantum and physicochemical properties associated with nanostructured particles.

Una reforma neoliberal de la UNC: mercantilización de educación superior en edX-UNCordobaX Torrano, María Andrea; Pagano, Miguel Maria El 21 de marzo de 2017, luego de un debate en el Consejo Superior, la UNC se incorporó al Consorcio edX fundado en 2012 por la Universidad de Harvard y el MIT (Massachusetts Institute of Technology). edX es un proyecto destinado a la educación "masiva, abierta y gratuita" a través de cursos online (MOOC) disponibles en el sitio edx.org. Dicho consorcio está compuesto por alrededor de 100 instituciones, entre universidades de distintas partes del mundo, empresas (como Microsoft) y organismos internacionales (FMI, Banco Mundial, BID).Algunos de los argumentos en el Consejo Superior para la incorporación de la UNC en este conglomerado incluyeron la actualización de la educación mediante la aplicación de nuevas tecnologías y de entornos educativos (cursos virtuales) sin costo y el posicionamiento de la UNC dentro del contexto mundial (medido a través de rankings internacionales). Sin embargo muchos son los elementos que nos hacen advertir que más que contribuir a garantizar el carácter público y gratuito de la enseñanza universitaria (art. 2 y 2 bis Ley 24.521 modificada en 2015), nos encontramos frente a un fenómeno encubierto de mercantilización de la educación y de pérdida de autonomía universitaria.

El equinodermo Gogia granulosa (Echinodermata: Blastozoa) del Cámbrico temprano-medio en Sonora, México: Paleoecología y paleogeografía; The echinoderm gogia granulosa (Echinodermata: Blastozoa) of early-mid cambrian in Sonora, Mexico: Paleoecology and paleogeography Buitrón Sánchez, B.A.; Cuen Romero F. J.; Montijo González, A,; Beresi, Matilde Sylvia Blastoids of Gogia granulosa Robison, 1965 and Gogia sp. have previously been reported from San Jose de Gracia, Sonora, Mexico. Here we report on the implications of their presence in limestone, shale, and sandstone from the lower-middle Cambrian of that site. The biotic association consists of blastoids, as well as trilobites (Onchocephalus, Bonnia, Bristolia, Olenellus), hyolithids (Hyolithes, Haplophrentis), sponges, algae and ichnofossils of echinoderms (Asteriacites, Asterosoma). The community suggests that the depositional environment was a carbonated platform of tropical, shallow sea, with well oxygenated water. The biota belonged to a large faunistic province that comprised parts of Canada, USA and Mexico (Panthalassic Ocean).

A cost reduction procedure for control-restricted nonlinear systems Gómez Múnera, John Anderson; Rivadeneira Paz, Pablo Santiago; Costanza, Vicente This paper describes a numerical scheme to approximate the solution of the optimal control problem for nonlinear systems with restrictions on the manipulated variables. The method proposed here systematically reduces the cost associated with successively updated control strategies after proposing an initial seed trajectory. It follows two main lines of reasoning, the first one relying on linearizations around a seed state/control trajectory and exploiting a theoretical expression for the increment of the cost. This setup is valid in regular situations, and it can be used when saturations occur after some adaptations. One of its advantages is that the decreasing of the cost can be assessed without integrating numerically the nonlinear dynamics. However, and because of the constraints, eventually this method fails, and an alternative approach must be activated to continue decreasing the cost. The alternative approach is based on specific control variations of the current control strategy, and it is activated depending on two theoretical criteria (failure alert) developed here. The first control variation proposed is derived from the differential Riccati equation for the linearized system and appropriate quadratic cost functions. Other variations, similar to those used in Pontryagin theorem for generating the final cone of states, are proposed by modifying the locations of ‘switching times’, producing oscillations in the interior of regular periods. The performance of the numerical proposed method and the related mathematical objects are illustrated by optimizing two-dimensional nonlinear systems with a scalar bounded control.

Marco jurídico de la gestión internacional de las unidades subestatales. Un estudio comparado de Argentina, Bolivia y Chile; Legal framework for the substates international management. A comparative study between Argentina, Bolivia and Chile Juste, Stella Maris Los cambios acaecidos en el sistema internacional y el posicionamiento de las unidades subestatales como actores del mismo trae a escena el replanteamiento del rol del Estado en las relaciones internacionales. El presente trabajo investigativo se ocupará de analizar cómo se configura la gestión internacional de las unidades subestatales de acuerdo al marco jurídico estatal. A los efectos de esta investigación se analizarán los casos de Argentina, Bolivia y Chile, haciendo especial referencia a las unidades subestatales de Jujuy, Tarija y Tarapacá respectivamente. En tal sentido las preguntas que guían la investigación son: ¿En qué marco se configura la gestión internacional de las unidades subestatales? ¿Reconoce el Estado la gestión internacional de las unidades que lo conforman? ¿De qué manera lo hace? ¿Qué tipo de relación se plantea entre el Estado y las unidades subestatales? La capacidad de las unidades subestatales para actuar de manera directa en el plano internacional ha sido reiteradamente reconocida, pero su fundamento jurídico se encuentra disperso a lo largo de las normas legales de cada Estado y debe ser inferido del contexto, lo que implica que no existe un cuerpo legal genérico que determine de forma explícita en qué forma pueden o no actuar internacionalmente las unidades subestatales. De esta manera, la inserción internacional de las unidades subestatales se verá afectada por el grado de autonomía que le otorgue el marco constitucional del Estado que conforman y por el marco de la política exterior.; The befallen changes within the International System and the placement of sub-state units as performers in the same reassessment stage of the State’s role in International Affairs. The current research work will analyze how the international management of sub-state units is set according to the State’s legal framework. The cases of Argentina, Bolivia and Chile will be analyzed with special reference to the sub-units of Jujuy, Tarija and Tarapacá, accordingly. The inquiries that serve as a guideline are: In which framework is the international management of sub-state units set? Is the international management of those component units recognized by the State? How is it acknowledged? What kind of relation is raised between the State and sub-state units? The sub-state units ability to act directly with the international level has been acknowledged repeatedly, but its legal grounds are scattered among the framework legislation of each State and has to be inferred by context, which implies that there’s no legal text that determines explicitly how are the sub-state units to act or not internationally. Thus, the international insertion of sub-state units will be affected by the autonomy level given by the legal framework from eachState and that of foreign policy.

Jump events in a 3D Edwards-Anderson spin glass Mártin, Daniel Alejandro; Iguain, Jose Luis The statistical properties of infrequent particle displacements, greater than a certain distance, are known as jump dynamics in the context of structural glass formers. We generalize the concept of a jump to the case of a spin glass, by dividing the system into small boxes, and considering the infrequent cooperative spin flips in each box. Jumps defined this way share similarities with jumps in structural glasses. We perform numerical simulations for the 3D Edwards-Anderson model, and study how the properties of these jumps depend on the waiting time after a quench. Similar to the results for structural glasses, we find that while jump frequency depends strongly on time, the jump duration and jump length are roughly stationary. At odds with some results reported on studies of structural glass formers, at long enough times, the rest time between jumps varies as the inverse of jump frequency. We give a possible explanation for this discrepancy. We also find that our results are qualitatively reproduced by a fully-connected trap model.

Twisting Hopf algebras from cocycle deformations Andruskiewitsch, Nicolas; Garcia Iglesias, Agustin Let H be a Hopf algebra. Any finite-dimensional lifting of V∈HHYD arising as a cocycle deformation of A= B(V) # H defines a twist in the Hopf algebra A∗, via dualization. We follow this recipe to write down explicit examples and show that it extends known techniques for defining twists. We also contribute with a detailed survey about twists in braided categories.

Hecke and sturm bounds for Hilbert modular forms over real quadratic fields Burgos Gil, Jose Ignacio; Pacetti, Ariel Martín Let K be a real quadratic field and OK its ring of integers. Let Γ be a congruence subgroup of SL2(OK) and M(k1,k2)(Γ) be the finite dimensional space of Hilbert modular forms of weight (k1, k2) for Γ. Given a form f(z) ∈ M(k1,k2)(Γ), how many Fourier coefficients determine it uniquely in such space? This problem was solved by Hecke for classical forms, and Sturm proved its analogue for congruences modulo a prime ideal. The present article solves the same problem for Hilbert modular forms over K. We construct a finite set of indices (which depends on the cusps desingularization of the modular surface attached to Γ) such that the Fourier coefficients of any form in such set determines it uniquely.

Detection of myocardial infarction using delayed enhancement dualenergy CT in stable patients Rodriguez Granillo, Gaston Alfredo; Campisi, Roxana; Deviggiano, Alejandro; de Munain, Maria N. Lopez; De Zan, Macarena; Capunay, Carlos; Carrascosa, Patricia OBJECTIVE. The objective of our study was to explore whether delayed enhancement dual-energy CT (DECT) allows the detection of myocardial infarcts in stable patients. SUBJECTS AND METHODS. Patients with known or suspected coronary artery disease clinically referred for myocardial perfusion imaging using SPECT were prospectively included. All patients (n = 34) also underwent stress, rest, and delayed enhancement DECT on a DECT scanner. At SPECT, segments with myocardial infarction (MI) were defned as those with a summed rest score of = 2 in two or more consecutive segments, and a diagnosis of MI was supported by wall motion abnormalities, clinical history, and ECG fndings. RESULTS. Segments with MI were identifed in 13 (38%), 15 (44%), and 14 (41%) patients using SPECT, perfusion CT, and delayed enhancement DECT, respectively. When combined SPECT and perfusion CT results were used as the reference standard, delayed enhancement DECT had a sensitivity, specifcity, positive predictive value, and negative predictive value for the detection of MI of 91.7% (95% CI, 62-98%), 86.4% (95% CI, 65-97%), 78.6% (95% CI, 49-95%), and 95.0% (95% CI, 75-100%). At delayed enhancement DECT (40 keV), a signal attenuation higher than 161 HU had a sensitivity of 72% and a specifcity of 79% for the detection of MI on a per-segment basis. The median signal attenuation of myocardial infarcts at 40 keV was 3.0 SDs (interquartile range, 1.3-4.0 SDs) above that of normal myocardium. CONCLUSION. In this study, delayed enhancement DECT allowed the detection of myocardial infarcts in stable patients.

Therapeutic blockade of Foxp3 in experimental breast cancer models Moreno Ayala, Mariela Alejandra; Gottardo, María Florencia; Imsen, Mercedes; Asad, Antonela Sofía; Bal, Elisa Dora; Casares, Noelia; Lasarte, Juan José; Seilicovich, Adriana; Candolfi, Marianela Purpose: Regulatory T cells (Tregs) impair the clinical benefit of cancer immunotherapy. To optimize the antitumor efficacy of therapeutic dendritic cell (DC) vaccines, we aimed to inhibit Foxp3, a transcription factor required for Treg function. Methods: Mice bearing established syngeneic LM3 and 4T1 breast tumors were treated with antitumor DC vaccines and a synthetic peptide (P60) that has been shown to inhibit Foxp3. Results: Treatment with P60 improved the therapeutic efficacy of DC vaccines in these experimental models. In addition, monotherapy with P60 inhibited tumor growth in immunocompetent as well as in immuno-compromised animals bearing established tumors. We found expression of Foxp3 in human and murine breast tumor cells. P60 inhibited IL-10 secretion in breast cancer cells that expressed Foxp3. Conclusions: Our results suggest that Foxp3 blockade improves the therapeutic efficacy of DC vaccines by inhibition of Tregs and through a direct antitumor effect. This strategy could prove useful to neutralize the immunosuppressive microenvironment and to boost antitumor immunity in breast cancer.

Los rankings globales de universidades y su función disciplinaria; The global rankings of universities and their disciplinary function Crisci, Jorge Victor; Apodaca, María José En la última década los rankings de universidades se han transformado en una fuerza importante con gran influencia en las políticas universitarias locales y globales. Mientras que en algunos países se han llevado a cabo rankings nacionales desde el siglo pasado, los rankings globales de universidades son un fenómeno reciente que tomó fuerza a principios del siglo XXI. Los rankings son vistos como una forma cuantitativa de dar cuenta de responsabilidades y obligaciones institucionales, y la transparencia y calidad de la administración. Hoy día existen, al menos, diez rankings globales de universidades, los cuatro más conocidos son: Academic Ranking of World Universities, SCImago Institutions Rankings, QS World University Rankings, y World University Ranking. Las metodologías de estos rankings son sumariamente presentadas y se discute qué miden y qué no miden. Dos de los más importantes indicadores de todos los rankings (el prestigio y el uso de índices de citas como medida de la calidad de la producción científica) son discutidos críticamente. Se aplica el concepto de disciplina de Foucault para comprender cómo los rankings implícitamente favorecen un cierto modelo de organización de estudios superiores.; Over the last decade, rankings of universities have become a significant force impacting on and influencing higher education policy. While rankings have been part of some national academic system for many years, global rankings are a XXI century phenomenon. Rankings are viewed as a way to demonstrate accountability by formal, quantitative measures. Today there are, at least, ten major global rankings of universities. The most well-known are: Academic Ranking of World Universities, SCImago Institutions Rankings, QS World University Rankings, and World University Ranking. The methodologies of these rankings are briefly presented. What global rankings do measure and what they do not measure is discussed. Two of the most important indicators of rankings (reputation and the use of citation-base indicators for research evaluation) are critically discussed. The application of Foucault´s concept of discipline to rankings, helps to understand how rankings implicitly apply pressure on universities in favor of a specific model of higher education organization.

An Asymmetric Multi-Item Auction with Quantity Discounts Applied to Internet Service Procurement in Buenos Aires Public Schools Bonomo, Flavia; Catalán, Jaime; Duran, Ricardo Guillermo; Epstein, Rafael; Guajardo, Mario; Jawtuschenko, Alexis Boris; Marenco, Javier Leonardo This article studies a multi-item auction characterized by asymmetricbidders and quantity discounts. We report a practical application of thistype of auction in the procurement of Internet services to the 709 publicschools of Buenos Aires. The asymmetry in this application is due to firms?existing technology infrastructures, which affect their ability to providethe service in certain areas of the city. A single round first-price sealed-bidauction, it required each participating firm to bid a supply curve specifyinga price on predetermined graduated quantity intervals and to identify theindividual schools it would supply. The maximal intersections of the setsof schools each participant has bid on define regions we call competitionunits. A single unit price must be quoted for all schools supplied withinthe same quantity interval, so that firms cannot bid a high price wherecompetition is weak and a lower one where it is strong. Quantity discountsare allowed so that the bids can reflect returns-to-scale of the suppliers andthe auctioneer may benefit of awarding bundles of units instead of separateunits. The winner determination problem in this auction poses a challengeto the auctioneer. We present an exponential formulation and a polynomialformulation for this problem, both based on integer linear programming.The polynomial formulation proves to find the optimal set of bids in amatter of seconds. Results of the real-world implementation are reported.

Does Echinoderm research deserve an ethical consideration? Rubilar Panasiuk, Cynthia Tamara; Crespi Abril, Augusto Cesar Traditional ethics reflection centers the discussion in conflicts that affect humans. According toepistemology-based ethics, facts are needed to include other living beings as object of ethical consideration. Inthis sense, huge efforts have been made to demonstrate that animal suffering is real. However, the ethical reflectiononly reaches large vertebrates and some species of small ones, excluding invertebrates. However, a differentapproach (ethic-based epistemology) is equally valid and questions the assumptions of traditional ethics. Thisnew insight does not demand facts to demonstrate that living beings should be considered ethically, since ethicsshould be first than epistemology (facts). Thus, all living beings should be treated with respect and a relationshipbased on empathy should be established. In this context, we discuss all the advances made in echinodermresearch in the last 3000 years and the different uses humans made of these organisms. Finally we emphasizethat, when studying echinoderms, a reflection about our behavior as researchers is necessary, and we encouragethe use of ethically responsible research.

Studies on the immature stages of the planthopper Lepidelphax pistiae (Hemiptera: Delphacidae), a potential biocontrol agent for the aquatic weed Pistia stratiotes (Araceae) from Argentina Marino, Ana Maria; Defea, Bárbara Soledad; Rusconi, José Matías; Cabrera Walsh, Guillermo José Descriptions of the immature stages of the planthopper Lepidelphax pistiae Remes Lenicov (Fulgoromorpha), a specialist herbivore of Pistia stratiotes L. (Alismatales) from Argentina, are provided for the first time. P. stratiotes, or water lettuce, is an important weed in fresh water bodies of the tropics and subtropics. Newly emerged nymphs from eggs collected in the field were reared in rearing chambers. Fifth nymphal instars may be easily recognised by the whitish colour with a distinctive blackish antennal flagellum and ungues, and the relatively long frons and rostrum. Information is provided on nymphal behaviour and the main features of the fifth nymph instar that distinguish it from the two other delphacids that live and feed on plants from central and northern Argentine wetlands.

Probing the sea quark content of the proton with one-particle-inclusive processes Borsa Sanjuán, Ignacio; Sassot, Rodolfo; Stratmann, Marco We investigate the feasibility of constraining parton distribution functions in the proton through a comparison with data on semi-inclusive deep-inelastic lepton-nucleon scattering. Specifically, we reweight replicas of these distributions according to how well they reproduce recent, very precise charged kaon multiplicity measurements and analyze how this procedure optimizes the determination of the sea quark densities and improves their uncertainties. The results can help to shed new light on the long standing question on the size of the flavor and charge symmetry breaking among quarks of radiative origin. An iterative method is proposed and adopted to account for the inevitable correlation with what is assumed about the parton-To-hadron fragmentation functions in the reweighting procedure. It is shown how the fragmentation functions can be optimized simultaneously in each step of the iteration. As a first case study, we implement this method to analyze kaon production data.