The evolution and star formation of dwarf galaxies in the Fornax Cluster

We present the results of a spectroscopic survey of 675 bright (16.5 < b(J) < 18) galaxies in a 6 degrees field centred on the Fornax cluster with the FLAIR-II spectrograph on the UK Schmidt Telescope. Three galaxy samples were observed: compact galaxies to search for new blue compact dwarfs, candidate M 32-like compact dwarf ellipticals, and a subset of the brightest known cluster members in order to study the cluster dynamics. We measured redshifts for 516 galaxies, of which 108 were members of the Fornax Cluster. Defining dwarf galaxies to be those with b(J) greater than or equal to 15 (M-B greater than or equal to - 16.5), there are a total of 62 dwarf cluster galaxies in our sample. Nine of these are new cluster members previously misidentified as background galaxies. The cluster dynamics show that the dwarf galaxies are still falling into the cluster whereas the giants are virialized. We classified the observed galaxies as late-type if we detected H alpha emission at an equivalent width greater than 1 Angstrom. The spectra were obtained through fixed apertures, so they reflect activity in the galaxy cores, but this does not significantly bias the classifications of the compact dwarfs in our sample. The new classifications reveal a higher rate of star formation among the dwarf galaxies than suggested by morphological classification: 35 per cent have significant H alpha emission indicative of star formations but only 19 per cent were morphologically classified as late-types. The star-forming dwarf galaxies span the full range of physical sizes and we find no evidence in our data for a distinct class of star-forming blue compact dwarf (BCD) galaxy. The distribution of scale sizes is consistent with evolutionary processes which transform late-type dwarfs to early-type dwarfs. The fraction of dwarfs with active star formation drops rapidly towards the cluster centre: this is the usual density-morphology relation confirmed here for dwarf galaxies. The star-forming dwarfs are concentrated in the outer regions of the cluster, the most extreme in an infalling subcluster. We estimate gas depletion time-scales for five dwarfs with detected Hi emission: these are long (of order 10(10) yr), indicating that an active gas removal process must be involved if they are transformed into gas-poor dwarfs as they fall further into the cluster. Finally, in agreement with our previous results, we find no compact dwarf elliptical (M 32-like) galaxies in the Fornax Cluster.

Ultracompact dwarf galaxies in the Fornax Cluster

By utilizing the large multiplexing advantage of the Two-degree Field spectrograph on the Anglo-Australian Telescope, we have been able to obtain a complete spectroscopic sample of all objects in a predefined magnitude range, 16.5 < b(j) < 19.7 regardless of morphology, in an area toward the center of the Fornax Cluster of galaxies. Among the unresolved or marginally resolved targets, we have found five objects that are actually at the redshift of the Fornax Cluster; i.e., they are extremely compact dwarf galaxies or extremely large star clusters. All five have absorption-line spectra. With intrinsic sizes of less than 1.1 HWHM (corresponding to approximately 100 pc at the distance of the cluster), they are more compact and significantly less luminous than other known compact dwarf galaxies, yet much brighter than any globular cluster. In this paper we present new ground-based optical observations of these enigmatic objects. In addition to having extremely high central surface brightnesses, these objects show no evidence of any surrounding low surface brightness envelopes down to much fainter limits than is the case for, e.g., nucleated dwarf elliptical galaxies. Thus, if they are not merely the stripped remains of some other type of galaxy, then they appear to have properties unlike any previously known type of stellar system.

Ultra-compact dwarf galaxies: a new class of compact stellar system discovered in the Fornax Cluster

We have used the 2dF spectrograph on the Anglo-Australian Telescope to obtain a complete spectroscopic sample of all objects in the magnitude range, 16.5 < bj < 19.8, regardless of morphology, in an area centred on the Fornax Cluster of galaxies. Among the unresolved targets are five objects which are members of the Fornax Cluster. They are extremely compact stellar systems with scale lengths less than 40 parsecs. These ultra-compact dwarfs are unlike any known type of stellar system, being more compact and significantly less luminous than other compact dwarf galaxies, yet much brighter than any globular cluster.

The effect of nutrient enrichment on growth, photosynthesis and hydraulic conductance of dwarf mangroves in Panama

1. Dwarf stands of the mangrove Rhizophora mangle L. are extensive in the Caribbean. We fertilized dwarf trees in Almirante Bay, Bocas del Toro Province, north-eastern Panama with nitrogen (N) and phosphorus (P) to determine (1) if growth limitations are due to nutrient deficiency; and (2) what morphological and/or physiological factors underlie nutrient limitations to growth. 2. Shoot growth was 10-fold when fertilized with P and twofold with N fertilization, indicating that stunted growth of these mangroves is partially due to nutrient deficiency. 3. Growth enhancements caused by N or P enrichment could not be attributed to increases in photosynthesis on a leaf area basis, although photosynthetic nutrient-use efficiency was improved. The most dramatic effect was on stem hydraulic conductance, which was increased sixfold by P and 2.5-fold with N enrichment. Fertilization with P enhanced leaf and stem P concentrations and reduced C : N ratio, but did not alter leaf damage by herbivores. 4. Our findings indicate that addition of N and P significantly alter tree growth and internal nutrient dynamics of mangroves at Bocas del Toro, but also that the magnitude, pattern and mechanisms of change will be differentially affected by each nutrient.

A dynamic analysis of human welfare in a warming planet

Climate science indicates that climate stabilization requires low GHG emissions. Is thisconsistent with nondecreasing human welfare?Our welfare or utility index emphasizes education, knowledge, and the environment. Weconstruct and calibrate a multigenerational model with intertemporal links provided by education,physical capital, knowledge and the environment.We reject discounted utilitarianism and adopt, first, the Pure Sustainability Optimization (orIntergenerational Maximin) criterion, and, second, the Sustainable Growth Optimization criterion,that maximizes the utility of the first generation subject to a given future rate of growth. We applythese criteria to our calibrated model via a novel algorithm inspired by the turnpike property.The computed paths yield levels of utility higher than the level at reference year 2000 for allgenerations. They require the doubling of the fraction of labor resources devoted to the creation ofknowledge relative to the reference level, whereas the fractions of labor allocated to consumptionand leisure are similar to the reference ones. On the other hand, higher growth rates requiresubstantial increases in the fraction of labor devoted to education, together with moderate increasesin the fractions of labor devoted to knowledge and the investment in physical capital.

Memoria de la elaboración de subtítulos para "Babel", primer capítulo de la serie documental Fry's Planet Word

This work tries to identify some of the skills an audio visual translator must develop, from a practical point of view, in order to pursue a career in this field, putting the stress on mastering subtitling-specific software. This report describes trial and error process during the making of the subtitles for a documentary and identifies some of the difficulties we might encounter while working on an assignment of this kind if we work with free licensing software. Moreover, it tries to contribute with some answers to these issues.

Chlormequat chloride and ethephon affect growth and yield formation of conventional, naked and dwarf oat

Selostus: Kasvunsääteiden vaikutukset tavanomaisen, paljasjyväisen ja kääpiökauran kasvuun ja sadonmuodostukseen

Peduncle and fruit yield, in six cropping seasons, of early dwarf cashew tree clones irrigated with different water regimes

The objective of this work was to evaluate peduncle and fruit yield in clone MS 076 and in a clonal population of drip-irrigated, early dwarf cashew trees propagated by layering, in six cropping seasons. In order to meet the increased water requirements of the crop resulting from plant growth and development, irrigation during the dry season was performed daily according to the following water regime: 15 min/plant/day during the 1st year, 30 min/plant/day during the 2nd year, 45 min/plant/day during the 3rd year and 60 min/plant/day during all subsequent years. Water was supplied by one drip emitter/plant, at an (adjustable) flow rate of 36 L/h.The research was carried out in Fortaleza-Ceará, Brazil, and a random block design was utilized, with five replicates and split-plots. The clones were assigned to plots and the cropping seasons were considered as subplots. The clonal population was superior to the clone only with regard to number of nut shells (NNS), and solely in the first season. The clone was superior to the population as to NNS and peduncle yield (PY) in the second season, and also with regard to the three evaluated traits - NNS, PY, and nut shell yield, in the last three cropping seasons.

Barley Yellow Dwarf Virus (BYDV) y los áfidos en los arrozales levantinos: una prospección

Se ha llevado a cabo una prospección de las poblaciones emigrantes de áfidos alados en el área de La Albufera de Valencia, zona donde se da el «enrojat» del arroz, enfermedad causada por una raza del Barley Yellow Dwarf Virus, y se discute aquí el potencial presumible de las distintas especies como vectores de la enfermedad. Se muestrearon dos áreas con diferente incidencia de la enfermedad, obteniéndose 30 especies, de las que ocho están descritas como vectores de tales virus. Fueron mayores las capturas en las áreas donde se cultivaba el arroz por plantel y transplante con incidencia marcada de la enfermedad, que en otras de menor incidencia. La aparente homogeneidad de la zona hace difícil comprender la razón de tales diferencias. Entre los vectores conocidos de BYDV, sólo Rhopalosiphon padi L. y Hyaiopterus pruni (L) Geof. aparecieron al principio de la estación, cuando tiene lugar la infección, con poblaciones considerables. E1 primero es el vector conocido de la enfermedad. El segundo, es de las pocas especies que tiene niveles similares de captura en ambas áreas. Ninguno de los otros áfidos vectores capturados como alados parece verdaderamente importante para la transmisión a pleno campo por lo tardío de su llegada a los campos o por razones de su ciclo vital. Se ha intentado estudiar el potencial de Hyalopterus pruni, pulgón muy abundante en los carrizos como transmisor a corta distancia a partir de estas plantas. No se han obtenido resultados positivos ni a partir de la planta, ni a partir de áfidos alimentados en arroz o avena infectadas previamente con la enfermedad.

Addition of nitrogen had no effect on yield and quality of apples in an high density orchard carrying a dwarf rootstock

The effect of N addition on apple yield and quality may vary according to the tree vigor. Apple trees developed over vigorous rootstocks had shown no response to N application in Brazil. In this study it was evaluated the effect of N addition to the soil on yield and quality of ´Royal Gala´ apples grafted on a dwarf rootstock (M.9). The orchard was planted in 1995 (2,857 trees ha-1) on an Oxisol containing 40 g kg-1 of organic matter and pH 6.0. The experiment was carried out from 1998 up to 2005. Treatments consisted of rates of N (0, 50, 100 and 150 kg ha-1 year-1 from 1998 to 2001, and respectively 0, 100, 200 and 300 kg ha-1 afterwards), all broadcasted within the tree row in two equal splits, at bud break and after harvest, as ammonium sulfate. Addition of N to the soil had no effect on fruit yield over the six years regardless of the applied rate. Averaged across treatments and years, fruit yield was 52.3 t ha-1. Nitrogen in the leaves (average of 24 g kg-1) or in the fruits (average of 346 mg kg-1) as well as some attributes related to fruit quality (color, firmness, acidity, soluble solids, physiological disorders) were unaffected by N addition. Some plant parameters related to tree vigor, however, grew higher with the increase on N rate. Thus, it is not necessary to apply N to deep Brazilian soils containing high organic matter in order to assure good fruit quality and yield on high-density orchards carrying dwarf rootstocks probably because the N required for tree growth and fruit production is supplied from soil organic matter decay.

Alterations in growth and canopy architecture among dwarf, semidwarf and tall oat lines grown under northern conditions

Selostus: Korkeudeltaan eri tyyppisten kauralinjojen kasvu ja sadontuotto pohjoisissa viljelyoloissa

Quince 'CPP': new dwarf rootstock for pear trees on organic and high density planting

In Brazil, pear production presents the same incipient situation over the last 15 years, due mostly to low production technology. In this context, this study aimed to evaluate the development, growth and production of the pear tree cultivars Cascatense, Tenra and Hosui grafted on 'CPP' quince rootstock, using 'FT' pear as interstem. This trial was carried out in Guarapuava, State of Paraná, Southern region of Brazil, by five productive cycles. The pear trees were planted in September of 2004, spaced at 1.0 x 4.0 m (2,500 trees ha-1), trained to the modified central leader, on a Four-wire trellis, with drip irrigation and cultivated under organic production system. The following variables were evaluated: sprouting, anthesis, yield, fruit weight, soluble solids content, titratable acidity, pulp firmness, canopy area per plant and per hectare and trunk diameter. The pear tree cv. Tenra was outstanding most of the years for fruit yield, and, consequently, showed the highest accumulated yield over the period (51.6 t ha-1), followed by the cultivars Cascatense (39.7 t ha-1) and Hosui (18.7 t ha-1). All pear cultivars presented suitable physical-chemical characteristics for commercial purposes, with minimal average soluble solids content of 11% at harvest. The maximum canopy area per hectare was attained for cv. Cascatense (3063.2 m²), that was considered insufficient for a high yield. These results suggest the needs for studies with higher density planting and other training systems, searching optimize canopy volume. One of the most limiting factors in the organic pear orchard was the incidence of pear dieback caused by Botriosphaeria dothidea, severe more often in pear trees cv. Hosui.