On Scale Invariance and Anomalies in Quantum Mechanics

We re-consider the quantum mechanics of scale invariant potentials in two dimensions. The breaking of scale invariance by quantum effects is analyzed by the explicit evaluation of the phase shift and the self-adjoint extension method. We argue that the breaking of scale invariance reported in the literature for the $\delta$(r) potential, is an example of explicit and not an anomaly or quantum mechanical symmetry breaking.Comment: 15 pp in latex, no figure

Assessing the Level of Effectiveness of Marketing Activities of HEIs in the National Capital Region

Higher Education Institutions in the Philippines, just as any business institutions, conduct marketing activities to ensure the thriving admission and retention of students. This paper ascertained the effectiveness of the marketing activities used by selected HEIs in the National Capital Region through the “Four P’s of Marketing”. Results of the study can be used as references by HEIs in updating their marketing activities. Keywords: Marketing Activities, Four Ps of Marketing, Higher Education Institutio

La variabilidad en el razonamiento probabilístico informal de estudiantes de bachillerato

En esta comunicación se exploran las respuestas de los estudiantes a dos tareas binomiales, de predicción y de distribución, para conocer cómo expresan la variabilidad en sus predicciones antes y después de actividades de simulación. Para la recolección de datos, se realizó un estudio de cuatro etapas con dos grupos de estudiantes, uno que no había tomado un curso de probabilidad y estadística, y otro que había tomado uno. La primera y cuarta etapa consistió en aplicar un cuestionario relacionado con una situación binomial b(x, 2, ½). En la segunda y tercera etapa, los estudiantes llevaron a cabo simulaciones físicas y con el software Fathom, respectivamente. En el análisis se destacan las dificultades que enfrentan los estudiantes en la integración de la variabilidad en sus razonamientos, a pesar de su experiencia con la simulación. Se proponen dos categorías para describir patrones de respuesta: dogmatismo teórico y compromiso empírico

Nanostructural differences in pectic polymers isolated from strawberry fruits with low expression levels of pectate lyase or polygalacturonase genes

Our research group has obtained transgenic strawberry plants expressing antisense sequences of either a pectate lyase (APEL lines) [1] or a polygalacturonase gene (APG lines) [2]. Both genes encode ripening-specific endo-pectinases with a common target, deesterified homogalacturonans, but each enzyme act by a different mechanism and pH range. Ripe fruits from both transgenic genotypes were significantly firmer than control, being APG fruits on average 25% firmer than APEL fruits. Cell wall analysis of both transgenic genotypes indicated that pectin fractions extracted with CDTA and sodium carbonate were significantly modified in transgenic fruits [2,3]. To gain insight in the role of these pectinases in pectin disassembly during ripening, CDTA and Na2CO3 pectins have been analyzed by atomic force microscopy (AFM). APEL and APG CDTA pectins had similar contour lengths but both were significantly longer than control. Similarly, APG carbonate chains were longer than control, showing APEL carbonate chains an intermediate length. Furthermore, transgenic pectins displayed a more complex branching pattern and a higher number of micellar aggregates, especially in the sodium carbonate fractions of APG samples. Acid hydrolysis of carbonate pectins reduced the number of micellar aggregates. AFM analyses confirm that the inhibition of both pectinases reduces pectin disassembly, and also suggest that each pectinase acts on specific pectin domains. Particularly, polygalacturonase silencing induces more significant pectin modifications, nicely correlated with the firmer phenotype of APG fruits, than the down-regulation of pectate lyase

Future challenges of representing land-processes in studies on land-atmosphere interactions

Over recent years, it has become increasingly apparent that climate change and air pollution need to be considered jointly for improved attribution and projections of human-caused changes in the Earth system. Exchange processes at the land surface come into play in this context, because many compounds that either act as greenhouse gases, as pollutant precursors, or both, have not only anthropogenic but also terrestrial sources and sinks. And since the fluxes of multiple gases and particulate matter between the terrestrial biota and the atmosphere are directly or indirectly coupled to vegetation and soil carbon, nutrient and water balances, quantification of their geographic patterns or changes over time requires due consideration of the underlying biological processes. In this review we highlight a number of critical aspects and recent progress in this respect, identifying in particular a number of areas where studies have shown that accounting for ecological process understanding can alter global model projections of land-atmosphere interactions substantially. Specifically, this concerns the improved quantification of uncertainties and dynamic system responses, including acclimation, and the incorporation of exchange processes that so far have been missing from global models even though they are proposed to be of relevance for our understanding of terrestrial biota-climate feedbacks. Progress has also been made regarding studies on the impacts of land use/land cover change on climate change, but the absence of a mechanistically based representation of human responseprocesses in ecosystem models that are coupled to climate models limits our ability to analyse how climate change or air pollution in turn might affect human land use. A more integrated perspective is necessary and should become an active area of research that bridges the socio-economic and biophysical communities

Evaluating the Effectiveness of Marketing Mix Used By Transport Network Vehicle Services

This research assessed the level of effectiveness of the 4Ps or the marketing mix employed by Grab Car using the Four Ps of Marketing—Price, Place, Promotion, and to identify if Grab Car really is living up to the expectations of the riding public in the NCR. Findings may have shown that passengers are satisfied with the services provided by Grab Car, focusing on the concerns of the commuters can still be used by Grab and other Transport Network Vehicle Services in improving their marketing strategies. Keywords: Grab Car, Marketing Mix, Marketing Strategies, Transport Network Vehicle Service

Nanostructural changes in cell wall pectins during strawberry fruit ripening assessed by atomic force microscopy

Rapid loss of firmness occurs during strawberry (Fragaria × ananassa Duch) ripening, resulting in a short shelf life and high economic losses. The disassembly of cell walls is considered the main responsible for fruit softening, being pectins extensively modified during strawberry ripening (Paniagua et al. 2014). Atomic force microscopy allows the analysis of individual polymer chains at nanostructural level with a minimal sample preparation (Morris et al., 2001). The main objective of this research was to compare pectins of green and red ripe strawberry fruits at the nanostructural level to shed light on structural changes that could be related to softening. Cell walls from strawberry fruits were extracted and fractionated with different solvents to obtain fractions enriched in a specific component. The yield of cell wall material, as well as the amount of the different fractions, decreased in ripe fruits. CDTA and Na2CO3 fractions underwent the largest decrements, being these fractions enriched in pectins supposedly located in the middle lamella and primary cell wall, respectively. Uronic acid content also decreased significantly during ripening in both pectin fractions, but the amount of soluble pectins, those extracted with phenol:acetic acid:water (PAW) and water increased in ripe fruits. Monosaccharide composition in CDTA and Na2CO3 fractions was determined by gas chromatography. In both pectin fractions, the amount of Ara and Gal, the two most abundant carbohydrates, decreased in ripe fruits. The nanostructural characteristics of CDTA and Na2CO3 pectins were analyzed by AFM. Isolated pectic chains present in the CDTA fraction were significantly longer and more branched in samples from green fruits than those present in samples obtained from red fruit. In spite of slight differences in length distributions, Na2CO3 samples from unripe fruits displayed some longer chains at low frequency that were not detected in ripe fruits. Pectin aggregates were more frequently observed in green fruit samples from both fractions. These results support that pectic chain length and the nanostructural complexity of the pectins present in CDTA and Na2CO3 fractions diminish during strawberry fruit development, and these changes, jointly with the loss of neutral sugars, could contribute to the solubilization of pectins and fruit softening. Paniagua et al. (2014). Ann Bot, 114: 1375-1383 Morris et al. (2001). Food Sci Tech 34: 3-10 This research was supported by FEDER EU Funds and the Ministerio de Educación y Ciencia of Spain (grant reference AGL2011-24814)Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Unravelling the nanostructure of strawberry fruit pectins by atomic force microscopy

Atomic force microscopy (AFM) allows the analysis of individual polymers at nanostructural level with a minimal sample preparation. This technique has been used to analyse the pectin disassembly process during the ripening and postharvest storage of several fleshy fruits. In general, pectins analysed by AFM are usually visualized as isolated chains, unbranched or with a low number of branchs and, occasionally, as large aggregates. However, the exact nature of these structures is unknown. It has been suggested that pectin aggregates represent a mixture of rhamnonogalacturonan I and homogalacturonan, while isolated chains and their branches are mainly composed by polygalacturonic acid. In order to gain insight into the nature of these structures, sodium carbonate soluble pectins from ripe strawberry (Fragaria x ananassa, Duch.) fruits were subjected to enzymatic digestion with endo-Polygalacturonase M2 from Aspergillus aculeatus, and the samples visualized by AFM at different time intervals. Pectins isolated from control, non-transformed plants, and two transgenic genotypes with low level of expression of ripening-induced pectinase genes encoding a polygalacturonase (APG) or a pectate lyase (APEL) were also included in this study. Before digestion, isolated pectin chains from control were shorter than those from transgenic fruits, showing number-average (LN) contour length values of 73.2 nm vs. 95.9 nm and 91.4 nm in APG and APEL, respectively. The percentage of branched polymers was significantly higher in APG polyuronides than in the remaining genotypes, 33% in APG vs. 6% in control and APEL. As a result of the endo-PG treatment, a gradual decrease in the main backbone length of isolated chains was observed in the three samples. The minimum LN value was reached after 8 h of digestion, being similar in the three genotypes, 22 nm. By contrast, the branches were not visible after 1.5-2 h of digestion. LN values were plotted against digestion time and the data fitted to a first-order exponential decay curve, obtaining R2 values higher than 0.9. The half digestion time calculated with these equations were similar for control and APG pectins, 1.7 h, but significantly higher in APEL, 2.5 h, indicating that these polymer chains were more resistant to endo-PG digestion. Regarding the pectin aggregates, their volumes were estimated and used to calculate LN molecular weights. Before digestion, control and APEL samples showed complexes of similar molecular weights, 1722 kDa, and slightly higher than those observed in APG samples. After endo-PG digestion, size of complexes diminished significantly, reaching similar values in the three pectin samples, around 650 kDa. These results suggest that isolated polymer chains visualized by AFM are formed by a HG domain linked to a shorter polymer resistant to endo-PG digestion, maybe xylogalacturonan or RG-I. The silencing of the pectate lyase gene slightly modified the structure and/or chemical composition of polymer chains making these polyuronides more resistant to enzymatic degradation. Similarly, polygalacturonic acid is one of the main component of the aggregates.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Seedling Production Systems for Smallholder Forestry Development: Local Practices versus National Policies in the Philippines

The tree seedling nursery sector in the Philippines is influenced by a number of national level policies affecting the number and type of species produced. Policies favour high-volume production of a limited range of mostly exotic species, and research indicates that seedlings are often of low physical and genetic quality. Local knowledge on best species for sites is not being communicated to people planting. A project funded by the Australian Centre for International Agricultural Research is investigating measures to improve the performance and effectiveness of the forestry seedling production system in Leyte and Mindanao in the Philippines. Seedlings are produced by government agencies, in community forestry projects and by individual private operators; the main customers are smallholder tree farmers. Communities and private individuals quickly set up nurseries when there is a demand for seedlings, but these nurseries tend to be ephemeral and lack financial sustainability. While large nurseries offer opportunities for economies of scale, small nurseries operate on a low cost basis, and are more widely distributed, and their seedlings are more accessible to smallholders, who lack transport facilities. Small private nurseries, while having limited access to new technology, often produce seedlings of quality similar to government and community nurseries. However, they require assistance in access to high-quality germplasm and training in improved seed production technology, to play a greater role in expansion of plantation forestry. This paper reports survey findings on seedling production systems, and examines the link between national level policies and local level practices