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En el artículo Jorge L. Rodríguez introduce la discusión alrededor del texto de Cristina Redondo y el problema de la relación entre reglas y normas. Además de resumir algunas de las posturas centrales de la discusión, propone su propio punto de vista sobre uno de los múltiples aspectos discutidos. Según el autor el tema central es el de la relevancia práctica de las normas generales. Esto como mínimo da lugar a diversas concepciones: la universalista y la particularista.

Background: People Who Inject Drugs (PWID) are at a higher risk of acquiring bloodborne infections. This study aimed to estimate the prevalence of Hepatitis C Virus (HCV) in People Who Inject Drugs (PWID) and identify correlates and risk factors using data from the Puerto Rico National HIV Behavioral System, PWID cycle 5 conducted in 2018.Methods: A total of 502 San Juan Metropolitan Statistical Area participants were recruited through Respondent Driven Sampling method. Sociodemographic, health-related, and behavioral characteristics were assessed. Detection of HCV antibodies was completed after the face-to-face survey. Descriptive and logistic regression analyses were performed using STATA 17™. Results: The prevalence of HCV was 76.5% (95%CI: 70.8%-81.4%). Adjusted multivariate logistic regression models showed that frequent speedball injectors and knowing the HCV serostatus of the last sharing partner were significantly more associated with HCV infection (ORa = 4.17; 95% CI: 1.40-12.42; ORa = 4.49; 95% CI: 1.43-14.09, respectively).Conclusions: A high prevalence of HCV infection in PWID was observed in this sample, validating the continuing call for local action for public health and prevention strategies.

El análisis de los comentarios y críticas presente en este número nos ha permitido repensar algunos puntos sobre el tema, y el presente trabajo es el fruto de tales reflexiones. En él no se pretende ofrecer una respuesta a todas las cuestiones en discusión, sino sólo avanzar algunas ideas adicionales, básicamente respecto de la distinción entre la inconstitucionalidad de una norma jurídica y su declaración por un órgano de control, el nexo que media entre tal distinción y la concepción que se adopte respecto de la interpretación de las normas y ciertos aspectos vinculados con la dinámica de los sistemas constitucionales.

Se explorará el tradicional problema de la existencia de las normas inconstitucionales con el propósito de disolverlo, mostrando la dependencia que media entre el modo en que las normas pueden existir y el concepto de “norma” que se asuma. Se analizarán centralmente dos nociones de norma: la que las identifica con formulaciones normativas no interpretadas y la que las identifica con formulaciones normativas interpretadas. Aprovechando la distinción entre sistema y orden jurídico se examinarán dos modelos de reconstrucción del resultado que producen los actos de promulgación y derogación de normas. Sobre tales bases, se intentará demostrar la independencia conceptual entre la inconstitucionalidad de una norma y su derogación. A continuación se evaluarán los diferentes sistemas de control de constitucionalidad. El análisis se cerrará con el estudio crítico de un fallo reciente de los tribunales argentinos.

Although they come from different traditions, Hans Kelsen and W. N. Hohfeld have offered two essential contributions to the clarification of fundamental legal concepts. After a brief review of their proposals, certain problematic aspects of their reconstructions will be analyzed in the light of categories developed by Eugenio Bulygin, in particular his criticism of the reductionist conceptions of norms, the non-prescriptive character of power-conferring rules, and the distinction between norms and norm-propositions. On this basis, and starting from the concept of legal obligation, an outline of an alternative reconstruction of the theory of fundamental legal concepts will be presented. | The Spanish original of this article was published in Revus (2018) 36.

In mice, the host response to malaria weakens colonization resistance to an enteric pathogen by suppressing gastric acidity., Malaria parasite infection weakens colonization resistance against Salmonella enterica serovar (S.) Typhimurium. S. Typhimurium is a member of the Enterobacterales, a taxon that increases in abundance when the colonic microbiota is disrupted or when the colonic mucosa is inflamed. However, here, we show that infection of mice with Plasmodium yoelii enhances S. Typhimurium colonization by weakening host control in the upper GI tract. P. yoelii–infected mice had elevated gastric pH. Stimulation of gastric acid secretion during P. yoelii infection restored stomach acidity and colonization resistance, demonstrating that parasite-induced hypochlorhydria increases gastric survival of S. Typhimurium. Furthermore, blockade of P. yoelii–induced TNF-α signaling was sufficient to prevent elevation of gastric pH and enhance S. Typhimurium colonization during concurrent infection. Collectively, these data suggest that abundance in the fecal microbiota of facultative anaerobes, such as S. Typhimurium, can be increased by suppressing antibacterial defenses in the upper GI tract, such as gastric acid.

En su último libro Cristina Redondo efectúa una excelente defensa de la postura a la que califica como positivismo jurídico interno, de acuerdo con la cual sería posible formular enunciados referidos al contenido del derecho, concebido este como una entidad normativa, que sean puramente descriptivos y expresados desde un punto de vista que no presupone su aceptación. En este trabajo me limitaré a tres observaciones más bien marginales, desarrollando algunas dudas, en primer lugar, sobre la estrategia de impugnación de la denominada tesis de la imposibilidad; en segundo lugar, sobre un punto vinculado a los dos sentidos de la distinción entre punto de vista interno y externo que Redondo propone diferenciar y, en tercer lugar, respecto de una consecuencia que se derivaría de ello para la evaluación crítica de teorías interpretativistas como la de Ronald Dworkin, para luego formular algunas conclusiones de ese análisis. Redondo's last book excellently defends what she calls the 'internal legal positivism', i.e. a position according to which it is possible to formulate statements relating to the content of the law conceived as a normative entity, which are purely descriptive and are expressed from a point of view that does not presuppose its acceptance. In this essay I will limit myself to developing three rather marginal observations that raise some doubts: first, about the strategy of questioning the so-called impossibility thesis; second, about a point related to Redondo's disambiguation of the distinction between internal and external points of view; and third, about a consequence derived from this for the critical evaluation of interpretativist theories such as Dworkin's.

From 2010-2014, colorectal cancer (CRC) was the second highest incident cancer and leading cause of cancer-related deaths in Puerto Rico (PR). Although preventable through screening and treatment, colorectal cancer screening (CRCS) using fecal occult blood test (FOBT) or colonoscopy remains low for adults in PR. Data from the 2016 Behavioral Risk Factor Surveillance System indicated that 18.0% of the PR population aged 50 to 75 had undergone an FOBT within the past year compared to 8.0% in the United States (US). Additionally, 50.1% of age-eligible Puerto Ricans report ever having a colonoscopy in the past 10 years compared to 63.5% in the US. Given the higher burden of CRC and the low CRCS rates in PR, we developed ¡Salud!, por la Vida (SPLV), an educational program which aims to increase CRCS in non-adherent men and women aged 50 and 75 who attend Federally Qualified Health Clinics (FQHCs) in PR. We used Intervention Mapping (IM) as framework to develop an educational intervention that is theoretically sound and grounded in evidence. For the development of SPLV, steps 1 to 4 of IM were completed. Step 1: a needs assessment conducted through focus groups and key informant interviews to gather quantitative and qualitative data for the development of the logic model and the program; step 2: development of a logic model of change and matrices of change objectives; step 3: selection of theory and evidence-based methods and strategies; and step 4: program production, components, and materials. Step 1 revealed 5 main themes: (1) lack of knowledge about CRC and CRCS practices; (2) patient’s fear of the CRC test results; (3) low risk perception of CRC; (4) lack of provider CRCS recommendation; and (5) the importance of social support. Interviews revealed that the majority of clinics offer FOBT as part of their CRCS protocol; where 74.0% of these had a clinical laboratory on-site. Over half (53.0%) had implemented electronic medical records and 82.0% had health educators on staff. A logic model was developed by combining personal behaviors with behavioral determinants and identifying beliefs targeted by the intervention (step 2). Tailored interactive multimedia intervention (TIMI) and small media were selected as the practical application to deliver the intervention (step 3). Development of the program included 5 components: script development; testimonials; animations; written materials; and newsletter. Pre-testing was conducted to evaluate the usability of the program. Our educational program, SPLV, is completed and currently being implemented, using a randomized trial. Trial is being conducted in 10 FQHCs and will recruit 710 participants aged 50 to 75 who have no prior history of CRC and are not adherent to CRCS guidelines. Clinics are randomized to either the intervention group (TIMI) or the control group (usual care). We aim that this intervention will significantly increase CRCS rates and provide evidence to disseminate this educational effort to FQHCs in PR. Citation Format: Vivian Colón-López, Camille Vélez-Alamo, Adrianna Acevedo-Fontanez, Marievelisse Soto-Salgado, Jorge L Rodríguez-Lebrón, Josheili Y Llavona-Ortiz, Yolanda Serra-Martínez, Ileska Valencia-Torres, María Fernández. ¡Salud!, por la Vida, an educational intervention to increase colorectal cancer screening in Puerto Ricans [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B009.

Hans Kelsen y W. N. Hohfeld, desde diferentes tradiciones, han ofrecido dos contribuciones imprescindibles para el esclarecimiento de los conceptos jurídicos básicos. Tras un breve repaso de sus propuestas, se analizarán algunos aspectos deficitarios de sus reconstrucciones a la luz de categorías desarrolladas por Eugenio Bulygin en diversos trabajos, en particular sus críticas al reduccionismo normativo, la imposibilidad de identificar las reglas que confieren potestades con prescripciones y la distinción entre normas y proposiciones normativas. Sobre tales bases, y tomando como punto de partida al concepto de deber jurídico, se ofrecerá finalmente un bosquejo de reconstrucción alternativa de la teoría de los conceptos jurídicos básicos. Hans Kelsen and W. N. Hohfeld, from different traditions, have offered two essential contributions for the clarification of the fundamental legal concepts. After a brief review of their proposals, certain problematic aspects of their reconstructions will be analyzed in the light of categories developed by Eugenio Bulygin in several papers, in particular his criticism of normative reductionism, the impossibility of identifying power-conferring rules with prescriptions, and the distinction between norms and norm-propositions. On this basis, and taking as a starting point the concept of legal obligation, an outline of an alternative reconstruction of the theory of fundamental legal concepts will be presented.

We analyze the economic returns to post-secondary degrees in Chile. We posit a schooling decision model with unobserved ability, degree-specific tuition costs, and earnings. We use administrative records to carry out our empirical analysis. Our results show positive average returns to post-secondary education, especially for five-year degrees. However, we also uncover significant heterogeneity. We document how unobserved characteristics (ability) determine the economic benefits of first- and second-best choices, even leading to negative returns to post-secondary degrees. Our findings illustrate the importance of allowing for heterogeneous treatment effects and individuals’ choices when examining the returns to education.

Obesity is prevalent in PR and has been associated with prostate cancer (PCa) mortality and aggressiveness. Polymorphisms (SNPs)The study population consisted of 513 Puerto Rican men age ranging from 40-79 years old who underwent radical prostatectomy (RP) as the first treatment for PCa and 128 healthy Puerto Rican men age ranging from 40-79 years old. Genomic DNA (gDNA) was extracted and SNPs were determined by Real-Time PCR. PCa severity was defined based on RP stage and Gleason Score. The relationship of FTO SNPs with demographic, clinical characteristics, PCa status and PCa severity were assessed. Logistic regression models with a 95% confidence interval (CI) determined SNPs interaction with PCa risk and severity odds ratio (ORs).BMI, age and PSA were considered as confounders. Hardy-Weinberg equilibrium was present for both SNPs. The heterozygous forms (Results offer a research line to be followed with an expanded number of subjects that may provide a better statistical significance, to unravel the high mortality rate in this population.

Background: Obesity is prevalent in PR and has been associated with prostate cancer (PCa) mortality and aggressiveness. Polymorphisms (SNPs) rs9930506 and rs9939609 in the FTO gene have been associated with both obesity and PCa. The aim of this work was to ascertain whether the presence of these SNPs is associated with PCa risk and severity in a cohort of Puerto Rican men. Methods and findings: The study population consisted of 513 Puerto Rican men age ranging from 40-79 years old who underwent radical prostatectomy (RP) as the first treatment for PCa and 128 healthy Puerto Rican men age ranging from 40-79 years old. Genomic DNA (gDNA) was extracted and SNPs were determined by Real-Time PCR. PCa severity was defined based on RP stage and Gleason Score. The relationship of FTO SNPs with demographic, clinical characteristics, PCa status and PCa severity were assessed. Logistic regression models with a 95% confidence interval (CI) determined SNPs interaction with PCa risk and severity odds ratio (ORs). Results and discussion: BMI, age and PSA were considered as confounders. Hardy-Weinberg equilibrium was present for both SNPs. The heterozygous forms (A/G; T/A) were the most prevalent genotypes and the frequency of alleles and genotypes for both SNPs agreed with those published in 1000 genomes. Results suggest an inverse association between the mutated rs9939609 and the risk of having PCa (OR: 0.53, 95% CI: 0.31-0.92) and a positive association with overweight (OR: 1.05, 95% CI: 0.68-1.62). Importantly, among the cases that were overweight, those with mutated rs9939609 had a greater chance of high severity PCa (OR: 1.39, 95% CI: 0.84-2.32) although these results were not statistical significant upon adjustment. Limitations of the study were the relatively small cohort and lack of access to the weight history of all our subjects. Conclusion: Results offer a research line to be followed with an expanded number of subjects that may provide a better statistical significance, to unravel the high mortality rate in this population..

The paper deals with the notions of consistency, completeness, and coherence within the normative domain. It investigates their mutual relations by singling out relative (to negation) and absolute consistency, weak, strong and trivial completeness, and three different functions of coherence (simplification, integration, and defeasance). The main upshot of the inquiry is that coherence may be regarded as a complex combination of weak completeness and possible absence of consistency and strong completeness of a system of rules regarding a non-trivially complete/non-absolutely inconsistent system of underlying principles.

Prostate cancer (PCa) mortality in Puerto Rico (PR) is significantly higher (28.3/100,000 men) compared to US mainland Hispanics. Obesity is prevalent in PR and has been associated with PCa mortality and aggressiveness. Polymorphisms rs9939609 and rs9930506 in the FTO gene have been associated with both obesity and PCa in other populations. Previous work in our laboratory has shown that Puerto Rican patients who underwent radical prostatectomy (RP) and also had at least one G allele in the FTO rs9930506 polymorphism exhibited a greater likelihood for low severity PCa. The aim of this work was to ascertain whether the presence of both polymorphisms (rs9930506 and rs9939609) in tandem correlated with PCa severity in this Puerto Rican population. The study population consisted of the pathology specimens of 294 Puerto Rican PCa patients, aged 40-79 years old who underwent RP as definitive treatment for PCa. Genomic DNA was extracted from normal seminal vesicle paraffin-embedded tissue. Polymorphisms were determined by RT-PCR. PCa severity was defined based on RP stage and Gleason Score. Chi-square test and logistic regression models were used to assess the correlation between FTO gene polymorphisms and PCa severity. Other factors such as BMI and age were considered in the model. We found that the A/G SNP in rs9930506 was present in 135 patients (45.9%). Likewise for rs9939609 we found the A/T SNP in 138 patients (46.9%). We found no statistically significant relationship between either polymorphism by itself and PCa severity. In 104 (35.4%) patients both SNPs were heterozygous. Of these, 77 (74%) were overweight or obese. Within this latter group, 55 (71.4%) exhibited low severity PCa. Data showed that those patients with simultaneous heterozygous forms had about 12% lower odds of low severity of PCa (95% CI: 0.52, 1.50), although no statistical significance was found for this relationship (p = 0.640). These results suggest that the presence of both polymorphisms in their heterozygous form may be related to low severity PCa in the obese/overweight group. Further studies are needed to understand the mechanisms that may be involved in this modulation of the development of severity in PCa in this population. This project was supported by RCMI grant G12MD007600 (Center for Collaborative Research in Health Disparities) and grant 8U54MD007587-03 (Puerto Rico Clinical and Translational Research Consortium) from the National Institute on Minority Health and Health Disparities, and by Award Grant Number# CA096297/CA096300 from the National Cancer Institute of the National Institutes of Health. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Citation Format: Jeannette Salgado-Montilla, Jorge Rodríguez-Caban, Lorena Gonzalez-Sepulveda, Ricardo Sanchez-Ortiz, Margarita Irizarry-Ramirez. Presence of FTO rs9939609 and rs9930506 and severity of prostate cancer in Puerto Ricans. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4836. doi:10.1158/1538-7445.AM2015-4836

The Gram-positive cocci (GPC), Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecalis and Enterococcus faecium, have become important causes of community and nosocomial-acquired infections. The prevalence of multiple resistant isolates to standard antimicrobial drugs has significantly increased over the past decades. Few prospective studies have been performed in Puerto Rico (PR) concerning the GPC antimicrobial susceptibilities pattern. The purpose of this study was to evaluate the in vitro susceptibility of GPC clinical isolates from PR to selected standard antibiotics and to the new antimicrobial agents, linezolid (LZ), quinupristin/dalfopristin (Q/D) and gemifloxacin (GM). The in vitro susceptibility utilizing disk diffusion and Etest methods to selected antibiotics was determined for a total of 429 isolates obtained during a period of 5 months from the Puerto Rico Medical Center Bacteriology Laboratory. The distribution of GPC collected was as follows: 213 S. aureus isolates, 162 E. faecalis, 16 E. faecium and 38 S. pneumoniae. The results of the susceptibility test demonstrated: 1) that in S. aureus, 100% of the isolates were susceptible to vancomycin (VAN), LZ and Q/D; 93% to GM; and 61% to methicillin/oxacillin; 2) in S. pneumoniae, 100% were susceptible to LN and GM; 87% to Q/D; and 53% to penicillin; 3) in E. faecalis, 99% were susceptible to ampicillin; 93% to LZ; 79% to GM; 78.6% to VAN; and 0% to Q/D. Sixty eight and 66% of the E. faecalis isolates were susceptible to gentamicin and streptomycin respectively; and 4) in E. faecium, 100% were susceptible to LZ; 94% to Q/D; 69% to GM; 37.5% to VAN and 20% to ampicillin. In E. faecium isolates, 50% and 31% were susceptible to gentamicin and streptomycin, respectively. Of the vancomycin resistant enterococci, 88.9% and 21% of E. faecium and faecalis showed VanA phenotypic resistance, respectively. These results show that there is a significant degree of antimicrobial resistance in GPC, including 38% methicillin resistance in S. aureus, a near 50% penicillin resistant S. pneumoniae, and a significant resistance of enterococcal species to VAN. The new agents, LZ, Q/D and GM, proved to be effective against both, S. aureus and S. pneumoniae. For E. faecium, both, LZ and Q/D were active, while for E. faecalis, only LZ showed consistent activity.

Al examinar el discurso normativo y su logica subyacente, una de las cuestiones de mayor importancia es la necesidad de apreciar con claridad las consecuencias que se siguen de la distincion, destacada entre otros por von Wright, entre normas y proposiciones normativas. Las normas son expresadas por formulaciones normativas; constituyen el significado de oraciones usadas para prescribir, esto es, para ordenar, prohibir o permitir ciertas conductas. Las proposiciones normativas, en cambio, constituirian el significado de oraciones que califican ciertas acciones como obligatorias, prohibidas o permitidas de conformidad con ciertas normas.1 Mientras que las proposiciones normativas son susceptibles de verdad o falsedad, no parece tener mayor sentido predicar tal cosa de las propias normas. La dificultad para distinguir estas dos nociones deviene de que la misma oracion (por ejemplo, “Esta prohibido fumar”) puede a veces ser utilizada para formular una norma y otras para referirse a la existencia de una norma, esto es, puede a veces expresar una norma y otras una proposicion normativa. Es verdaderamente lamentable que, pese a que con denominaciones diversas la diferencia que esta distincion recoge ha sido reconocida por muchos autores, ella no ha recibido todavia hoy la atencion que a mi juicio merece en el terreno de la logica del discurso normativo.2 Jorge L. Rodriguez

Background Sporothrix schenckii is a pathogenic dimorphic fungus of worldwide distribution. It grows in the saprophytic form with hyaline, regularly septated hyphae and pyriform conidia at 25°C and as the yeast or parasitic form at 35°C. Previously, we characterized a calcium/calmodulin kinase in this fungus. Inhibitors of this kinase were observed to inhibit the yeast cell cycle in S. schenckii. Results The presence of RNA interference (RNAi) mechanism in this fungus was confirmed by the identification of a Dicer-1 homologue in S. schenckii DNA. RNAi technology was used to corroborate the role of calcium/calmodulin kinase I in S. schenckii dimorphism. Yeast cells were transformed with the pSilent-Dual2G (pSD2G) plasmid w/wo inserts of the coding region of the calcium/calmodulin kinase I (sscmk1) gene. Transformants were selected at 35°C using resistance to geneticin. Following transfer to liquid medium at 35°C, RNAi transformants developed as abnormal mycelium clumps and not as yeast cells as would be expected. The level of sscmk1 gene expression in RNAi transformants at 35°C was less than that of cells transformed with the empty pSD2G at this same temperature. Yeast two-hybrid analysis of proteins that interact with SSCMK1 identified a homologue of heat shock protein 90 (HSP90) as interacting with this kinase. Growth of the fungus similar to that of the RNAi transformants was observed in medium with geldanamycin (GdA, 10 μM), an inhibitor of HSP90. Conclusions Using the RNAi technology we silenced the expression of sscmk1 gene in this fungus. RNAi transformants were unable to grow as yeast cells at 35°C showing decreased tolerance to this temperature. The interaction of SSCMK1 with HSP90, observed using the yeast two-hybrid assay suggests that this kinase is involved in thermotolerance through its interaction with HSP90. SSCMK1 interacted with the C terminal domain of HSP90 where effector proteins and co-chaperones interact. These results confirmed SSCMK1 as an important enzyme involved in the dimorphism of S. schenckii, necessary for the development of the yeast phase of this fungus. Also this study constitutes the first report of the transformation of S. schenckii and the use of RNAi to study gene function in this fungus.

Las relaciones entre los sistemas jurídicos nacionales y el Derecho internacional y, en particular, la recepción de las normas internacionales de tutela de los derechos humanos en el Derecho interno, constituyen problemas teóricos muy complejos y de una muy significativa relevancia institucional. Recientemente se ha ofrecido una nueva interpretación de tales relaciones, que apela a la distinción entre validez y aplicabilidad de las normas jurídicas. En el presente trabajo se efectuará un examen crítico de dicha propuesta, a cuyo fin se introducirán inicialmente algunas consideraciones aclaratorias en torno al significado y alcance de las nociones de validez y aplicabilidad, luego de lo cual se intentarán mostrar algunas consecuencias problemáticas de la reconstrucción bajo análisis, para concluir con algunos apuntes en torno a una posible presentación alternativa. The relations between national legal systems and international law and, more specifically, the reception of human rights international norms in national states, pose very complex theoretical difficulties of the utmost institutional relevance. In recent years a new interpretation of such relations has been offered, centered in the distinction between validity and applicability of legal norms. In this paper we offer a critical analysis of that proposal, introducing initially some preliminary remarks on the scope and meaning of the key notions of validity and applicability. On that basis we try to show some problematic consequences that follow from the interpretation examined and conclude with some observations in order to elaborate an alternative model of reconstruction.

Es bastante comun entre los juristas la idea de que no puede alcanzarse una solucion determinada para un caso individual unicamente a partir de las normas identificables explicitamente a partir de las fuentes de derecho admitidas como validas. En el ambito del derecho existiria mas de una solucion igualmente admisible para un caso individual de acuerdo a las normas generales expresamente formuladas por el legislador, pues no podria precisarse -por una u otra razoncuales son todas y cada una de las excepciones a que estan sujetas esas normas generales. Se dice, por ejemplo, que sin que hayan cambiado las normas que regulan un caso, jueces distintos pueden llegar a soluciones diferentes, sin caer por eso ninguno de ellos necesariamente en error. Para ejemplificarlo con un caso extremo en el derecho argentino, la Corte Suprema de Justicia al resolver el caso «Sejean» habilito el divorcio vincular pese a que una disposicion especifica de la entonces vigente ley de matrimonio civil vedaba expresamente esa posibilidad, pues considero que la norma en cuestion resultaba inconstitucional, pese a que venia siendo pacificamente aplicada por los jueces desde mucho tiempo atras. Las dos interpretaciones, segun esta idea intuitiva que venimos desarrollando, serian igualmente derivables del derecho vigente. Esto ha pretendido explicarse diciendo que el derecho, las normas generales, los «conceptos juridicos», son esencialmente «derrotables» 1 . Las

Desde diciembre de 1983 a enero de 1985 se probaron en invernadero 43 clones de caña de azúcar para resistencia al carbón, Ustilago scitaminea Sydow. Se inocularon 40 trozos de caña (semilla) por variedad (una yema/ semilla) sumergiéndolas por 20 min. en una suspensión acuosa de teliósporas (5 x 106/ml). La semilla inoculada se incubó durante la noche, después se sembró en cubos de metal de 20 cm. de diámetro. Se observó periódicamente la incidencia de la infección en cepas y tallos durante el desarrollo de la epifitotia. La infección en las cepas aumentó cuando la plantilla se dejó retoñar. Nueve clones mostraron resistencia al carbón y tres fueron tolerantes en la siembra de plantilla y en el retoño. Tres clones, PR 70-2085, PR 77-1040 y PR 78-3005, no mostraron los síntomas del carbón o brotes en forma de látigo en el transcurso del experimento.