A Drift-Diffusion Model of Interval Timing in the Peak Procedure

Drift-diffusion models (DDMs) are a popular framework for explaining response times in decision-making tasks. Recently, the DDM architecture has been used to model interval timing. The Time-adaptive DDM (TDDM) is a physiologically plausible mechanism that adapts in real-time to different time intervals while preserving timescale invariance. One key open question is how the TDDM could deal with situations where reward is omitted, as in the peak procedure—a benchmark in the timing literature. When reward is omitted, there is a consistent pattern of correlations between the times at which animals start and stop responding. Here we develop a formulation of the TDDM’s stationary properties that allows for the derivation of such correlations analytically. Using this simplified formulation we show that a TDDM with two thresholds–one to mark the start of responding and another the stop–can reproduce the same pattern of correlations observed in the data, as long as the start threshold is allowed to be noisy. We confirm this by running simulations with the standard TDDM formulation and show that the simplified formulation approximates well the full model under steady-state conditions. Moreover, we show that this simplified version of the TDDM is formally equivalent to Scalar Expectancy Theory (SET) under stationary behaviours, the most prominent theory of interval timing. This equivalence establishes the TDDM as a more complete drift-diffusion based theory with SET as a special case under steady-state conditions

Animal Production over Rice-Pasture Rotation System: Animal Performance

Fluctuations in commodity prices, determine the need to find strategies to stabilize production in farming systems. The rice - pastures rotation systems are a good example of this, where animal production takes place in the moments where rice is rotated with pastures (3 years rice and 2 years pastures). In this context, INIA has developed a technology adjusted to the east of the country, with the use of summer tillage to intensify livestock production through the incorporation of lambs fattening. These technologies, comercially validated with sheep-rice farming systems, can move the process of cattle backgrounding (males and females), but requires technological adjustments related to planting winter annuals species and the strategic use of the supplementation and subsequent evaluation of the impact of these proposed intensifications of the livestock production phase and subsequent rice production. There are now new tools to study the feasibility of these alternatives (productive and economic) through modelling, but the validity of their results will be based on the certainty of technical coefficients. These coefficients must be generated in real situations where all the factors interact (Deambrosi 2009). The objective of the present experiments, was to com-pare livewieght (LW) per hectare, daily gain (DG) and weight gain (WG) per animal on an annual ryegrass (‘LE 284’) sown over rice stubble, used for calf backgrounding, under the effect of two stocking rate, in the north of Uruguay

Neutral, risky or provocative? Trends in titling practices in complementary and alternative medicine articles (1995-2016)

This paper analyses the length and titling practices in the under-researched field of complementary and alternative medicine (CAM).  Our corpus consisted of 360 articles published between 1995 and 2016 in three CAM journals. The length and frequency of Nominal, Verbal and Question titles were compared across genres and over time. A 40% overall title length increase was found. Our study confirms that title length is related to genre, research paper (RP) titles being significantly longer than reviews and case report titles. Moreover, RP titles were found to exhibit the greatest length increase over time. In this study, Nominal titles were the most frequent title type in the three genres and over the 20-year period analyzed, although they slightly decreased over time. In contrast, Verbal (full sentence) titles increased over time, especially in RP titles. Question titles were the only type that significantly increased over time, especially in review article titles. These findings were compared with those obtained by previous titleology research on conventional (CONV) medicine paper titles. We conclude that although CAM and CONV are divergent approaches to health care, their titling practices revealed more similarities than differences. These similarities may reflect a growing tendency towards practices associated with popular media to attract readership, such as use of Question and Verbal titles. This competition for attention could have serious implications for health care if the trend increases for clinicians to rely on the titles of relevant articles to make therapeutic decisions

The Rescorla-Wagner Drift-Diffusion Model

Computational models of classical conditioning have made significant contributions to the theoretic understanding of associative learning, yet they still struggle when the temporal aspects of conditioning are taken into account. Interval timing models have contributed a rich variety of time representations and provided accurate predictions for the timing of responses, but they usually have little to say about associative learning. In this thesis we present a unified model of conditioning and timing that is based on the influential Rescorla-Wagner conditioning model and the more recently developed Timing Drift-Diffusion model. We test the model by simulating 11 experimental phenomena and show that it can provide an adequate account for 9, and a partial account for the other 2. We argue that the model can account for more phenomena in the chosen set than these other similar in scope models: CSCTD, MS-TD, Learning to Time and Modular Theory. A comparison and analysis of the mechanisms in these models is provided, with a focus on the types of time representation and associative learning rule used

Prognostic significance of new onset ascites in patients with pancreatic cancer

BACKGROUND: The purpose of this study was to determine risk factors for development of malignant ascites and its prognostic significance in patients with pancreatic cancer. METHODS: A prospective database was queried to identify patients with pancreatic cancer who develop ascites. Stage at presentation, size, and location of primary tumor, treatment received and length of survival after onset of ascites were determined. RESULTS: A total of 15 patients were identified. Of which 4 patients (1 stage II, 3 stage III) underwent pancreaticoduodenectomy and manifested with ascites 2, 3, 24 and 47 months after surgery (tumor size 2.9 ± 1.32 cm). All but one of the remaining 11 patients (tumor size 4.4 ± 3.38 cm) presented with metastatic disease, and all developed malignant ascites 9 months after diagnosis, dying 2 months later. Resected patients lived longer before the onset of ascites, but not after. CONCLUSION: Once diagnosed, ascites in pancreatic cancer patients heralds imminent death. Limited survival should be considered when determining the aggressiveness of further intervention

Competencia y competitividad en la gestión de organizaciones agrícolas en Ecuador: el caso de los productores de Manabí y Esmeraldas

En el modelo económico actual de Ecuador persiste la dependencia sobre las exportaciones de petróleo, asunto que pone en riesgo su desarrollo sostenible. La nueva matriz productiva plantea retos que demandan cambios en la base de la estructura agroproductiva. Este trabajo tiene como objetivo evaluar las competencias para la gestión socio organizativa de las asociaciones de productores agrícolas. Con este fin se aplica el modelo de competencias para la gestión de agronegocios rurales presentado por la Organización Mundial de la Agricultura y Alimentos (FAO) en el 2006. Para la toma de datos se utilizó la entrevista semi estructurada y la observación de la gestión de 14 líderes de organizaciones productivas agrícolas en Manabí y Esmeraldas. Como resultado se presenta una matriz sobre el estado de desarrollo de las competencias para la gestión de los emprendimientos productivos rurales. Este procedimiento metodológico facilitó la aproximación a los procesos de desarrollo en los que se desempeñan los participantes. Palabras    clave:    Desarrollo    sustentable;    liderazgo, emprendimiento; comunidades; empresas rurales. Abstract Dependence on oil exports, matter that jeopardizes their sustainable development continues in the current economic model of Ecuador. The new productive matrix presented by the vice presidency of the Republic poses challenges that demand changes in the population of the commodity base. This work of descriptive character, aims to assess competencies for management organizational partner of the associations of agricultural producers. For this purpose apply the competency model for the management  of  rural  agrobusiness  presented  by  Food  and Agriculture  Organization  (FAO)  in  (2006).  For  the  data collection, we attend the interview semi structured and the observation of management style of 14 leaders of organizations of agricultural producers in the provinces of Manabi and Esmeraldas. We apply the approach to direct actors, since it facilitates the approach  to  the  development  process  in  which  participants perform. As a result is a matrix on the State of development of competencies for the management of the rural productive enterprises. Keywords: Sustainable development; Leadership; entrepreneurship; Communities; rural enterprises

Competencia y competitividad en la gestión de organizaciones agrícolas en Ecuador: el caso de los productores de Manabí y Esmeraldas

Dependence on oil exports, matter that jeopardizes their sustainable development continues in the current economic model of Ecuador. The new productive matrix presented by the vice presidency of the Republic poses challenges that demand changes in the population of the commodity base. This work of descriptive character, aims to assess competencies for management organizational partner of the associations of agricultural producers. For this purpose apply the competency model for the management  of  rural  agrobusiness  presented  by  Food  and Agriculture  Organization  (FAO)  in  (2006).  For  the  data collection, we attend the interview semi structured and the observation of management style of 14 leaders of organizations of agricultural producers in the provinces of Manabi and Esmeraldas. We apply the approach to direct actors, since it facilitates the approach  to  the  development  process  in  which  participants perform. As a result is a matrix on the State of development of competencies for the management of the rural productive enterprises.En el modelo económico actual de Ecuador persiste la dependencia sobre las exportaciones de petróleo, asunto que pone en riesgo su desarrollo sostenible. La nueva matriz productiva plantea retos que demandan cambios en la base de la estructura agroproductiva. Este trabajo tiene como objetivo evaluar las competencias para la gestión socio organizativa de las asociaciones de productores agrícolas. Con este fin se aplica el modelo de competencias para la gestión de agronegocios rurales presentado por la Organización Mundial de la Agricultura y Alimentos (FAO) en el 2006. Para la toma de datos se utilizó la entrevista semi estructurada y la observación de la gestión de 14 líderes de organizaciones productivas agrícolas en Manabí y Esmeraldas. Como resultado se presenta una matriz sobre el estado de desarrollo de las competencias para la gestión de los emprendimientos productivos rurales. Este procedimiento metodológico facilitó la aproximación a los procesos de desarrollo en los que se desempeñan los participantes

Drug Delivery to the Posterior Segment of the Eye: Biopharmaceutic and Pharmacokinetic Considerations

The treatment of the posterior-segment ocular diseases, such as age-related eye diseases (AMD) or diabetic retinopathy (DR), present a challenge for ophthalmologists due to the complex anatomy and physiology of the eye. This specialized organ is composed of various static and dynamic barriers that restrict drug delivery into the target site of action. Despite numerous efforts, effective intraocular drug delivery remains unresolved and, therefore, it is highly desirable to improve the current treatments of diseases affecting the posterior cavity. This review article gives an overview of pharmacokinetic and biopharmaceutics aspects for the most commonly-used ocular administration routes (intravitreal, topical, systemic, and periocular), including information of the absorption, distribution, and elimination, as well as the benefits and limitations of each one. This article also encompasses different conventional and novel drug delivery systems designed and developed to improve drug pharmacokinetics intended for the posterior ocular segment treatment

A competitive enzyme immunoassay for the quantitative detection of cocaine from banknotes and latent fingermarks

A sensitive and versatile competitive enzyme immunoassay (cEIA) has been developed for the quantitative detection of cocaine in complex forensic samples. Polyclonal anti-cocaine antibody was purified from serum and deposited onto microtiter plates. The concentration of the cocaine antibody adsorbed onto the plates, and the dilution of the cocaine-HRP hapten were both studied to achieve an optimised immunoassay. The method was successfully used to quantify cocaine in extracts taken from both paper currency and latent fingermarks. The limit of detection (LOD) of 0.162 ng mL-1 achieved with the assay compares favourably to that of conventional chromatography-mass spectroscopy techniques, with an appropriate sensitivity for the quantification of cocaine at the low concentrations present in some forensic samples. The cEIA was directly compared to LC-MS for the analysis of ten UK banknote samples. The results obtained from both techniques were statistically similar, suggesting that the immunoassay was unaffected by cross-reactivity with potentially interfering compounds. The cEIA was used also for the detection of cocaine in extracts from latent fingermarks. The results obtained were compared to the cocaine concentrations detected in oral fluid sampled from the same individual. Using the cEIA, we have shown, for the first time, that endogeneously excreted cocaine can be detected and quantified from a single latent fingermark. Additionally, it has been shown that the presence of cocaine, at similar concentrations, in more than one latent fingermark from the same individual can be linked with those concentrations found in oral fluid. These results show that detection of drugs in latent fingermarks could directly indicate whether an individual has consumed the drug. The specificity and feasibility of measuring low concentrations of cocaine in complex forensic samples demonstrates the effectiveness and robustness of the assay. The immunoassay presents a simple and cost-effective alternative to the current mass spectrometry based techniques for the quantitation of cocaine at forensically significant concentrations

Intravitreal implants manufactured by supercritical foaming for treating retinal diseases

Chronic retinal diseases, such as age-related macular degeneration (AMD), are a major cause of global visual impairment. However, current treatment methods involving repetitive intravitreal injections pose financial and health burdens for patients. The development of controlled drug release systems, particularly for biological drugs, is still an unmet need in prolonging drug release within the vitreous chamber. To address this, green supercritical carbon dioxide (scCO2) foaming technology was employed to manufacture porous poly(lactic-co-glycolic acid) (PLGA)-based intravitreal implants loaded with dexamethasone. The desired implant dimensions were achieved through 3D printing of customised moulds. By varying the depressurisation rates during the foaming process, implants with different porosities and dexamethasone release rates were successfully obtained. These implants demonstrated controlled drug release for up to four months, surpassing the performance of previously developed implants. In view of the positive results obtained, a pilot study was conducted using the monoclonal antibody bevacizumab to explore the feasibility of this technology for preparing intraocular implants loaded with biologic drug molecules. Overall, this study presents a greener and more sustainable alternative to conventional implant manufacturing techniques, particularly suited for drugs that are susceptible to degradation under harsh conditions