Neutral Pion Photoproduction on Nuclei in Baryon Chiral Perturbation Theory

Threshold neutral pion photoproduction on light nuclei is studied in the framework of baryon chiral perturbation theory. We obtain a general formula for the electric dipole amplitude in the special case of neutral pion photoproduction on a nucleus. To third order in small momenta, the amplitude is a sum of 2- and 3-body interactions with no undetermined parameters. With reasonable input from the single nucleon sector, our result for neutral pion photoproduction on the deuteron is in agreement with experiment.Comment: 24 pages, 4 uuencoded postscript figures, uses LaTex and epsf.tex. Added footnote and references. Minor changes in text and forma

Photochemical modelling in the Po basin with focus on formaldehyde and ozone

As part of the EU project FORMAT ( Formaldehyde as a Tracer of Oxidation in the Troposphere), a field campaign was carried out in the vicinity of Milan during the summer of 2002. Results from a 3-D regional chemical transport model (NILU RCTM) were used to interpret the observations focusing primarily on HCHO and ozone. The performance of the model was assessed by comparing model results with ground based and aircraft measurements. The model results show good agreement with surface measurements, and the model is able to reproduce the photochemical episodes during fair weather days. The comparison indicates that the model can represent well the HCHO concentrations as well as their temporal and spatial variability. The relationship between HCHO and (O-3 x H2O) was used to validate the model ability to predict the HCHO concentrations. Further analysis revealed the importance of the representativeness of different instruments: in-situ concentrations might be locally enhanced by emissions, while long path measurements over a forest can be influenced by rapid formation of HCHO from isoprene. The model is able to capture the plume from the city of Milan and the modelled levels agree generally well with the aircraft measurements, although the wind fields used in the model can lead to a displacement of the ozone plume. During the campaign period, O3 levels were seldom higher than 80 ppb, the peak surface ozone maxima reached 90 ppb. Those relatively low values can be explained by low emissions during the August vacation and unstable weather conditions in this period. The modelled Delta O-3/Delta NOz slope at Alzate of 5.1 agrees well with the measured slope of 4.9

CHIRAL BACKGROUND FOR THE TWO PION EXCHANGE NUCLEAR POTENTIAL: A PARAMETRIZED VERSION

We argue that the minimal chiral background for the two-pion exchange nucleon-nucleon interaction has nowadays a rather firm conceptual basis, which entitles it to become a standard ingredient of any modern potential. In order to facilitate applications, we present a parametrized version of a configuration space potential derived previously. We then use it to assess the phenomenological contents of some existing NN potentials.Comment: REVTEX style, 16 pages, 5 PostScript figures compressed, tarred and uuencode

A Review of the Applications of Chitin and Its Derivatives in Agriculture to Modify Plant-Microbial Interactions and Improve Crop Yields

In recent decades, a greater knowledge of chitin chemistry, and the increased availability of chitin-containing waste materials from the seafood industry, have led to the testing and development of chitin-containing products for a wide variety of applications in the agriculture industry. A number of modes of action have been proposed for how chitin and its derivatives can improve crop yield. In addition to direct effects on plant nutrition and plant growth stimulation, chitin-derived products have also been shown to be toxic to plant pests and pathogens, induce plant defenses and stimulate the growth and activity of beneficial microbes. A repeating theme of the published studies is that chitin-based treatments augment and amplify the action of beneficial chitinolytic microbes. This article reviews the evidence for claims that chitin-based products can improve crop yields and the current understanding of the modes of action with a focus on plant-microbe interactions

Organic Acids and Potential for Modifying the Avian Gastrointestinal Tract and Reducing Pathogens and Disease

Recently, antibiotics have been withdrawn from some poultry diets; leaving the birds at risk for increased incidence of dysbacteriosis and disease. Furthermore, mortalities occurring from disease contribute between 10 to 20% of production cost in developed countries. Currently, numerous feed supplements are being proposed as effective antibiotic alternatives in poultry diets, such as prebiotics, probiotics, acidic compounds, competitive exclusion products, herbs, essential oils, and bacteriophages. However, acidic compounds consisting of organic acids show promise as antibiotic alternatives. Organic acids have demonstrated the capability to enhance poultry performance by altering the pH of the gastrointestinal tract (GIT) and consequently changing the composition of the microbiome. In addition, organic acids, by altering the composition of the microbiome, protect poultry from pH-sensitive pathogens. Protection is further provided to poultry by the ability of organic acids to potentially enhance the morphology and physiology of the GIT and the immune system. Thus, the objective of the current review is to provide an understanding of the effects organic acids have on the microbiome of poultry and the effect those changes have on the prevalence of pathogens and diseases in poultry. From data reviewed, it can be concluded that the efficacy of organic acids on shifting microbiome composition is limited to the time of administration, the composition of the organic acid product, and the current health conditions of poultry

Experiencias de un Año de Servicio Social en las Unidades de Salud de Coatepeque y Texistepeque Octubre 1958 - Septiembre 1959

El objeto de esta tesis es compartir el trabajo que realizo el autor con su experiencia adquirida durante un año de Servicio Social , en donde desempeño el cargo de Director de las Unidades de Salud de las ciudades de Texistepeque y Coatepeque en el Departamento de Santa Ana. Para así poder poner al alcance del público y en especial de los Estudiantes de Medicina, todo sobre sus experiencias personales

Estudio de la natalidad, mortalidad y morbilidad en Texistepeque

Merced a la iniciativa del Departamento de Medicina Preventiva y Salud Pública y con la colaboración constante del Instituto de Nutrición de Centroamérica y Panamá (INCAP), estoy presentando este trabajo a la consideración de las personas estudiosas, que se identifican con el planteamiento y la búsqueda de medios favorables para la resolución de problemas trascendentales para nuestros pueblos del istmo. El contenido y proyecciones del presente trabajo, parece que no tiene precedentes en la historia de nuestro país, razón por la cual he puesto mi mejor esfuerzo en llevarlo a término de la manera más correcta. El estudio de la natalidad, mortalidad v morbilidad de nuestros pueblos, que en su mayoría constituyen núcleos sociales bastantes alejados de la capital de la República, más por las escasas y ruinosas vías de comunicación que por las distancias y en donde los servicios médicos son una novedad y la figura del médico únicamente despierta curiosidad, deben ser objeto del más cuidadoso estudio y meditación

Las Medidas de Seguridad

La pena es indispensable en toda comunidad, ello viene con firmado del hecho que dondequiera que exista ésta, es sentida la exigencia de una disciplina, de un orden, con un sistema punitivo que garantice la consistencia de los intereses en pugna. Esto lo podemos ver en cualquier comunidad: la familia, la escuela, la iglesia, el ejército, etc. La prueba decisiva de la indispensabilidad de la pena, nos la ofrece el hecho desconcertante del aumento de los actos criminales que se suceden al disminuir, ya sea en todo o en parte, la eficacia represiva del estado, causada por grandes calaminades, como los terremotos, los desordenes políticos internos, las derrotas militares, etc. El "Jus Puniendi”, constituye para el estado un medio necesario para hacer respetar su voluntad por sus ciudadanos, voluntad que no puede ser desobedecida si el estado pretende alcanzar sus propios fines de conservación y desarrollo. La función de la pena se identifica con su eficacia; en otras palabras, el concepto de función de la pena, presupone aquel de los efectos de la misma, en orden a un cierto fin. Este fin atribuido a la pena es distinto según las concepciones penales de que se trate, sin embargo en este punto sobresalen dos principios opuestos: a) el de la expiación o retribución que da a la pena un sentido de sufrimiento impuesto al delincuente como retribución por el delito que ha cometido y b) el de la prevención que tiene como finalidad prevenir la comisi6n de nuevos delitos. No obstante gran número de tratadistas seguidores del primer principio, también acogen el segundo y manifiestan que como la pena-castigo ejerce una acci6n intimidatoria sobre las masas, realiza también de esa manera una función preventiva

In vivo evaluation of the efficacy and safety of rapid short-pulse sequences for ultrasound-medicated delivery of agents to the brain

The blood-brain barrier is essential to the maintenance of homeostasis in the brain, but it also prevents 98% of small molecule drugs and imaging agents from entering the brain. Focused ultrasound in combination with microbubbles is a method that can increase the permeability of the blood-brain barrier in a non-invasive, localised and transient manner, allowing drugs and imaging agents into the brain. In conventional ultrasound methods, a sequence of long pulses is applied to the brain, which can cause undesired effects, such as uneven drug distributions and a barrier altered for several hours, exposing the brain to unwanted bloodborne substances. In this thesis, we have investigated whether the efficacy and safety of drug delivery can be improved in vivo by emitting ultrasound in a Rapid Short-Pulse (RaSP) sequence. We first investigated the differences in performance and safety between emitting a RaSP sequence and a long pulse sequence to deliver a dextran model drug. We found that a more uniform drug distribution was achieved using RaSP, with a delivered dose comparable to that of long pulses. The barrier permeability was altered for less than 10 minutes, minimising the amount of endogenous proteins entering the brain, while no tissue damage was observed. We then investigated whether RaSP could deliver large 100 nm liposomes into the brain. We showed that RaSP can achieve this with an improved safety profile, although higher pressures were needed compared to long pulses. Finally, we evaluated whether a dual-modal MRI-optical probe could be delivered into the brain, using long pulses, to image neurons. We confirmed uptake within neurons and detected both fluorescence and MRI signals ex vivo. This work demonstrates that ultrasound sequences can be designed to improve the efficacy and safety of drug delivery for the diagnosis and treatment of brain diseases.Open Acces