bluuebunny/crossref_metadata_2025 huggingface dataset:
Ice nuclei in marine air: biogenic particles or dust?
Authors: Burrows S. M. , Hoose C. , Pöschl U. , Lawrence M. G.
Published: January 2013

Abstract. Ice nuclei impact clouds, but their sources and distribution in the atmosphere are still not well known. Particularly little attention has been paid to IN sources in marine environments, although evidence from field studies suggests that IN populations in remote marine regions may be dominated by primary biogenic particles associated with sea spray. In this exploratory model study, we aim to bring attention to this long-neglected topic and identify promising target regions for future field campaigns. We assess the likely global distribution of marine biogenic ice nuclei using a combination of historical observations, satellite data and model output. By comparing simulated marine biogenic immersion IN distributions and dust immersion IN distributions, we predict strong regional differences in the importance of marine biogenic IN relative to dust IN. Our analysis suggests that marine biogenic IN are most likely to play a dominant role in determining IN concentrations in near-surface-air over the Southern Ocean, so future field campaigns aimed at investigating marine biogenic IN should target that region. Climate-related changes in the abundance and emission of biogenic marine IN could affect marine cloud properties, thereby introducing previously unconsidered feedbacks that influence the hydrological cycle and the Earth's energy balance. Furthermore, marine biogenic IN may be an important aspect to consider in proposals for marine cloud brightening by artificial sea spray production.
Future methane, hydroxyl, and their uncertainties: key climate and emission parameters for future predictions
Authors: Holmes C. D. , Prather M. J. , Søvde O. A. , Myhre G.
Published: January 2013

Abstract. Accurate prediction of future methane abundances following a climate scenario requires understanding the lifetime changes driven by anthropogenic emissions, meteorological factors, and chemistry-climate feedbacks. Uncertainty in any of these influences or the underlying processes implies uncertainty in future abundance and radiative forcing. We simulate methane lifetime in three chemical transport models (CTMs) – UCI CTM, GEOS-Chem, and Oslo CTM3 – over the period 1997–2009 and compare the models' year-to-year variability against constraints from global methyl chloroform observations. Using sensitivity tests, we find that temperature, water vapor, stratospheric ozone column, biomass burning and lightning NOx are the dominant sources of interannual changes in methane lifetime in all three models. We also evaluate each model's response to forcings that have impacts on decadal time scales, such as methane feedback, and anthropogenic emissions. In general, these different CTMs show similar sensitivities to the driving variables. We construct a parametric model that reproduces most of the interannual variability of each CTM and use it to predict methane lifetime from 1980 through 2100 following a specified emissions and climate scenario (RCP 8.5). The parametric model propagates uncertainties through all steps and provides a foundation for predicting methane abundances in any climate scenario. Our sensitivity tests also enable a new estimate of the methane global warming potential (GWP), accounting for stratospheric ozone effects, including those mediated by water vapor. We estimate the 100-yr GWP to be 32, which is 25% larger than past assessments.
Optical properties of Saharan dust aerosol and contribution from the coarse mode as measured during the Fennec 2011 aircraft campaign
Authors: Ryder C. L. , Highwood E. J. , Rosenberg P. D. , Trembath J. , Brooke J. K. , Bart M. , Dean A. , Crosier J. , Dorsey J. , Brindley H. , Banks J. , Marsham J. H. , McQuaid J. B. , Sodemann H. , Washington R.
Published: January 2013

Abstract. New in-situ aircraft measurements of Saharan dust originating from Mali, Mauritania and Algeria taken during the Fennec 2011 aircraft campaign over a remote part of the Sahara Desert are presented. Size distributions extending to 300 μm are shown, representing measurements extending further into the coarse mode than previously published for airborne Saharan dust. A significant coarse mode was present in the size distribution measurements with effective diameter (deff) from 2.3 to 19.4 μm and coarse mode volume median diameter (dvc) from 5.8 to 45.3 μm. The mean size distribution had a larger relative proportion of coarse mode particles than previous aircraft measurements. The largest particles (with deff > 12 μm, or dvc > 25 μm) were only encountered within 1 km of the ground. Number concentration, mass loading and extinction coefficient showed inverse relationships to dust age since uplift. Dust particle size showed a weak exponential relationship to dust age. Two cases of freshly uplifted dust showed quite different characteristics of size distribution and number concentration. Single Scattering Albed (SSA) values at 550 nm calculated from the measured size distributions revealed high absorption ranging from 0.70 to 0.97 depending on the refractive index. SSA was found to be strongly related to deff. New instrumentation revealed that direct measurements, behind Rosemount inlets, overestimate SSA by up to 0.11 when deff is greater than 2 μm. This is caused by aircraft inlet inefficiencies and sampling losses. Previous measurements of SSA from aircraft measurements may also have been overestimates for this reason. Radiative transfer calculations indicate that the range of SSAs during Fennec 2011 can lead to underestimates in shortwave atmospheric heating rates by 2.0 to 3.0 times if the coarse mode is neglected. This will have an impact on Saharan atmospheric dynamics and circulation, which should be taken into account by numerical weather prediction and climate models.
Free troposphere as the dominant source of CCN in the Equatorial Pacific boundary layer: long-range transport and teleconnections
Authors: Clarke A. D. , Freitag S. , Simpson R. M. C. , Hudson J. G. , Howell S. G. , Brekhovskikh V. L. , Campos T. , Kapustin V. N. , Zhou J.
Published: January 2013

Abstract. Airborne aerosol measurements in the central equatorial Pacific during PASE (Pacific Atmospheric Sulfur Experiment) revealed that cloud condensation nuclei (CCN) activated in marine boundary layer (MBL) clouds were dominated by entrainment from the free troposphere (FT). About 65% entered at sizes effective as CCN in MBL clouds, while 25% entered the MBL too small to activate but subsequently grew via gas to particle conversion. The remaining 10% were inferred to be sea-salt aerosol; there was no discernable nucleation in the MBL. FT aerosols at low carbon monoxide (CO) mixing ratios (< 63 ppbv) were small and relatively volatile with a number mode around 30–40 nm dry diameter and tended to be associated with cloud outflow from distant deep convection (3000 km or more). Higher CO concentrations were commonly associated with trajectories from South America and the Amazon region (ca. 10 000 km away) and occurred in layers indicative of combustion sources partially scavenged by precipitation. These had number mode near 60–80 nm diameter with a large fraction already CCN.2 (those activated at 0.2% supersaturation and representative of MBL clouds) before entrainment into the MBL. Flight averaged concentrations of CCN.2 were similar for measurements near the surface, below the inversion and above the inversion, confirming that subsidence of FT aerosol dominated MBL CCN.2. Concurrent flight-to-flight variations of CCN.2 at all altitudes below 3 km imply MBL CCN.2 concentrations were in quasi-equilibrium with the FT over a 2–3 day time scale. This extended FT transport over thousands of kilometers indicates teleconnections between MBL CCN and cloud-scavenged sources of both natural and/or residual combustion origin. The low aerosol scattering and mass in such layers results in poor detection by satellite and this source of CCN is not represented in most current models. The measurements confirm nucleation in the MBL was not evident during PASE and argue against the CLAW hypothesis being effective in this region during PASE.
Correction for a measurement artifact of the Multi-Angle Absorption Photometer (MAAP) at high black carbon mass concentration levels
Authors: Hyvärinen A.-P. , Vakkari V. , Laakso L. , Hooda R. K. , Sharma V. P. , Panwar T. S. , Beukes J. P. , van Zyl P. G. , Josipovic M. , Garland R. M. , Andreae M. O. , Pöschl U. , Petzold A.
Published: January 2013

Abstract. The Multi-Angle Absorption Photometer (MAAP) is a widely-used instrument for aerosol black carbon (BC) measurements. In this paper, we show correction methods for an artifact found to affect the instrument accuracy in environments characterized by high black carbon concentrations. The artifact occurs after a filter spot change – as BC mass is accumulated on a fresh filter spot, the attenuation of the light (raw signal) is weaker than anticipated. This causes a sudden decrease, followed by a gradual increase in measured BC concentration. The artifact is present in the data when the BC concentration exceeds ~3 μg m−3 at the typical MAAP flow rate of 16.7 L min−1 or 1 m3 h−1. The artifact is caused by erroneous dark counts in the photodetector measuring the transmitted light, in combination with an instrument internal averaging procedure of the photodetector raw signals. It was found that, in addition to the erroneous temporal response of the data, concentrations higher than 9 μg m−3 (at the flow rate of 16.7 L min−1) are underestimated by the MAAP. The underestimation increases with increasing BC accumulation rate. At a flow rate of 16.7 L min−1 and concentration of about 24 μg m−3 (BC accumulation rate ~0.4 μg min−1), the underestimation is about 30%. There are two ways of overcoming the MAAP artifact. One method is by logging the raw signal of the 165° photomultiplier measuring the reflected light from the filter spot. As this signal is not affected by the artifact, it can be converted to approximately correct absorption and BC values. However, as the typical print formats of the MAAP do not give the reflected signal as an output, a semi-empirical correction method was developed based on laboratory experiments to correct for the results in the post-processing phase. The correction function was applied to three MAAP datasets from Gual Pahari (India), Beijing (China), and Welgegund (South Africa). In Beijing, the results could also be compared against a photoacoustic spectrometer (PAS). The correction improved the quality of all three MAAP datasets substantially, even though the individual instruments operated at different flow rates and in different environments.
Pure rotational-Raman channels of the Esrange lidar for temperature and particle extinction measurements in the troposphere and lower stratosphere
Authors: Achtert P. , Khaplanov M. , Khosrawi F. , Gumbel J.
Published: January 2013

Abstract. The Department of Meteorology at Stockholm University operates the Esrange Rayleigh/Raman lidar at Esrange (68° N, 21° E) near the Swedish city of Kiruna. This paper describes the design and first measurements of the new pure rotational-Raman channel of the Esrange lidar. The Esrange lidar uses a pulsed Nd:YAG solid-state laser operating at 532 nm as light source with a repetition rate of 20 Hz and a pulse energy of 350 mJ. The minimum vertical resolution is 150 m and the integration time for one profile is 5000 shots. The newly implemented channel allows for measurements of atmospheric temperature at altitudes below 35 km and is currently optimized for temperature measurements between 180 and 200 K. This corresponds to conditions in the lower Arctic stratosphere during winter. In addition to the temperature measurements, the aerosol extinction coefficient and the aerosol backscatter coefficient at 532 nm can be measured independently. Our filter-based design minimizes the systematic error in the obtained temperature profile to less than 0.51 K. By combining rotational-Raman measurements (5–35 km height) and the integration technique (30–80 km height), the Esrange lidar is now capable of measuring atmospheric temperature profiles from the upper troposphere up to the mesosphere. With the improved setup, the system can be used to validate current lidar-based polar stratospheric cloud classification schemes. The new capability of the instrument measuring temperature and aerosol extinction furthermore enables studies of the thermal structure and variability of the upper troposphere/lower stratosphere. Although several lidars are operated at polar latitudes, there are few instruments that are capable of measuring temperature profiles in the troposphere, stratosphere, and mesosphere, as well as aerosols extinction in the troposphere and lower stratosphere with daylight capability.
Effect of elevated CO2 on the dynamics of particle-attached and free-living bacterioplankton communities in an Arctic fjord
Authors: Sperling M. , Piontek J. , Gerdts G. , Wichels A. , Schunck H. , Roy A.-S. , La Roche J. , Gilbert J. , Nissimov J. I. , Bittner L. , Romac S. , Riebesell U. , Engel A.
Published: January 2013

Abstract. In the frame of the European Project on Ocean Acidification (EPOCA), the response of an Arctic pelagic community (<3 mm) to a gradient of seawater pCO2 was investigated. For this purpose 9 large-scale in situ mesocosms were deployed in Kongsfjorden, Svalbard (78°56.2´ N, 11°53.6´ E), in 2010. The present study investigates effects on the communities of particle-attached (PA; >3 μm) and free-living (FL; < 3 μm > 0.2 μm) bacteria by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms, ranging from 185 to 1050 μatm initial pCO2, and the surrounding fjord. ARISA was able to resolve, on average, 27 bacterial band classes per sample and allowed for a detailed investigation of the explicit richness and diversity. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom, numbers of ARISA band classes in the PA community were reduced at low and medium CO2 (~ 185–685 μatm) by about 25%, while they were more or less stable at high CO2 (~ 820–1050 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2 mesocosms, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.
Riparian zone controls on base cation concentrations in boreal streams
Authors: Ledesma J. L. J. , Grabs T. , Futter M. N. , Bishop K. H. , Laudon H. , Köhler S. J.
Published: January 2013

Abstract. Forest riparian zones are a major in control of surface water quality. Base cation (BC) concentrations, fluxes, and cycling in the riparian zone merit attention because of increasing concern of negative consequences for re-acidification of surface waters from future climate and forest harvesting scenarios. We present a two-year study of BC and silica (Si) flow-weighted concentrations from 13 riparian zones and 14 streams in a boreal catchment in northern Sweden. The Riparian Flow-Concentration Integration Model (RIM) was used to estimate riparian zone flow-weighted concentrations and tested to predict the stream flow-weighted concentrations. Spatial variation in BC and Si concentrations as well as in flow-weighted concentrations was related to differences in Quaternary deposits, with the largest contribution from lower lying silty sediments and the lowest contribution from wetland areas higher up in the catchment. Temporal stability in the concentrations of most elements, a remarkably stable Mg / Ca ratio in the soil water and a homogeneous mineralogy suggest that the stable patterns found in the riparian zones are a result of distinct mineralogical upslope groundwater signals integrating the chemical signals of biological and chemical weathering. Stream water Mg / Ca ratio indicates that the signal is subsequently maintained in the streams. RIM gave good predictions of Ca, Mg, and Na flow-weighted concentrations in headwater streams. The difficulty in modelling K and Si suggests a stronger biogeochemical influence on these elements. The observed chemical dilution effect with flow in the streams was related to variation in groundwater levels and element concentration profiles in the riparian zones. This study provides a first step toward specific investigations of the vulnerability of riparian zones to changes induced by forest management or climate change, with focus on BC or other compounds.
Long-term summer sunshine/moisture stress reconstruction from tree-ring widths from Bosnia and Herzegovina
Authors: Poljanšek S. , Ceglar A. , Levanič T.
Published: January 2013

Abstract. We present the first summer sunshine reconstruction from tree-ring data for the western part of the Balkan Peninsula. Summer sunshine is tightly connected with moisture stress in trees, because the moisture stress and therefore the width of annual tree-rings is under the influence of the direct and interactive effects of sunshine duration (temperature, precipitation, cloud cover and evapotranspiration). The reconstruction is based on a calibrated z-scored mean chronology, calculated from tree-ring width measurements from 7 representative black pine (Pinus nigra Arnold) sites in Bosnia and Herzegovina (BiH). A combined regression and scaling approach was used for the reconstruction of the summer sunshine. We found a significant negative correlation (r = −0.54, p < 0.0001) with mean June–July sunshine hours from Osijek meteorological station (Croatia). The developed model was used for reconstruction of summer sunshine for the time period 1660–2010. We identified extreme summer events and compared them to available documentary historical sources of drought, volcanic eruptions and other reconstructions from the broader region. All extreme summers with low sunshine hours (1712, 1810, 1815, 1843, 1899 and 1966) are connected with volcanic eruptions.
Quantifying the model structural error in carbon cycle data assimilation systems
Authors: Kuppel S. , Chevallier F. , Peylin P.
Published: January 2013

Abstract. This study explores the impact of the structural error of biosphere models when assimilating net ecosystem exchange (NEE) measurements or CO2 concentration measurements to optimise uncertain model parameters within carbon cycle data assimilation systems (CCDASs). This error has been proven difficult to identify and is often neglected in the total uncertainty budget. We propose a simple method which is derived from the model-minus-observation mismatch statistics. This diagnosis is applied to a state-of-the-art biogeochemical model using measurements of the net surface CO2 flux at twelve sites located in temperate, deciduous, broadleaf forests. We find that the structural model error in the NEE space has a standard deviation of 1.5 to 1.7 gC m−2 d−1, without a significant correlation structure beyond the lag of a few days, and a large spatial structure that can be approximated with an exponential decay of e-folding length of 500 km. In the space of concentrations, its characteristics are commensurate with the transport errors, both for surface air sample measurements and total column measurements. The inferred characteristics are confirmed by complementary optimality diagnostics performed after site-scale parameter optimisations.
Exploiting remote sensing land surface temperature in distributed hydrological modelling: the example of the Continuum model
Authors: Silvestro F. , Gabellani S. , Delogu F. , Rudari R. , Boni G.
Published: January 2013

Abstract. Full process description and distributed hydrological models are very useful tools in hydrology as they can be applied in different contexts and for a wide range of aims such as flood and drought forecasting, water management, and prediction of impact on the hydrologic cycle due to natural and human-induced changes. Since they must mimic a variety of physical processes, they can be very complex and with a high degree of parameterization. This complexity can be increased by necessity of augmenting the number of observable state variables in order to improve model validation or to allow data assimilation. In this work a model, aiming at balancing the need to reproduce the physical processes with the practical goal of avoiding over-parameterization, is presented. The model is designed to be implemented in different contexts with a special focus on data-scarce environments, e.g. with no streamflow data. All the main hydrological phenomena are modelled in a distributed way. Mass and energy balance are solved explicitly. Land surface temperature (LST), which is particularly suited to being extensively observed and assimilated, is an explicit state variable. A performance evaluation, based on both traditional and satellite derived data, is presented with a specific reference to the application in an Italian catchment. The model has been firstly calibrated and validated following a standard approach based on streamflow data. The capability of the model in reproducing both the streamflow measurements and the land surface temperature from satellites has been investigated. The model has been then calibrated using satellite data and geomorphologic characteristics of the basin in order to test its application on a basin where standard hydrologic observations (e.g. streamflow data) are not available. The results have been compared with those obtained by the standard calibration strategy based on streamflow data.
A mechanistic description of the formation and evolution of vegetation patterns
Authors: Foti R. , Ramírez J. A.
Published: January 2013

Abstract. Vegetation patterns are a common and well-defined characteristic of many landscapes. In this paper we explore some of the physical mechanisms responsible for the establishment of self-organized, non-random vegetation patterns that arise at the hillslope scale in many areas of the world, especially in arid and semi-arid regions. In doing so, we provide a fundamental mechanistic understanding of the dynamics of vegetation pattern formation and development. Reciprocal effects of vegetation on the hillslope thermodynamics, runoff production and run-on infiltration, root density, surface albedo and soil moisture content are analyzed. In particular, we: (1) present a physically based mechanistic description of processes leading to vegetation pattern formation; (2) quantify the relative impact of each process on pattern formation; and (3) describe the relationships between vegetation patterns and the climatic, hydraulic and topographic characteristics of the system. We validate the model by comparing simulations with observed natural patterns in the areas of Niger near Niamey and Somalia near Garoowe. Our analyses suggest that the phenomenon of pattern formation is primarily driven by run-on infiltration and mechanisms of facilitation/inhibition among adjacent vegetation groups, mediated by vegetation effects on soil properties and controls on soil moisture and albedo. Nonetheless, even in presence of those mechanisms, patterns arise only when the climatic conditions, particularly annual precipitation and net radiation, are favorable.
Multi-variate flood damage assessment: a tree-based data-mining approach
Authors: Merz B. , Kreibich H. , Lall U.
Published: January 2013

Abstract. The usual approach for flood damage assessment consists of stage-damage functions which relate the relative or absolute damage for a certain class of objects to the inundation depth. Other characteristics of the flooding situation and of the flooded object are rarely taken into account, although flood damage is influenced by a variety of factors. We apply a group of data-mining techniques, known as tree-structured models, to flood damage assessment. A very comprehensive data set of more than 1000 records of direct building damage of private households in Germany is used. Each record contains details about a large variety of potential damage-influencing characteristics, such as hydrological and hydraulic aspects of the flooding situation, early warning and emergency measures undertaken, state of precaution of the household, building characteristics and socio-economic status of the household. Regression trees and bagging decision trees are used to select the more important damage-influencing variables and to derive multi-variate flood damage models. It is shown that these models outperform existing models, and that tree-structured models are a promising alternative to traditional damage models.
Density assumptions for converting geodetic glacier volume change to mass change
Authors: Huss M.
Published: January 2013

Abstract. The geodetic method is widely used for assessing changes in the mass balance of mountain glaciers. However, comparison of repeated digital elevation models only provides a glacier volume change that must be converted to a change in mass using a density assumption. This study investigates this conversion factor based on a firn compaction model applied to simplified glacier geometries with idealized climate forcing, and two glaciers with long-term mass balance series. It is shown that the "density" of geodetic volume change is not a constant factor and is systematically smaller than ice density in most cases. This is explained by the accretion/removal of low-density firn layers, and changes in the firn density profile with positive/negative mass balance. Assuming a value of 850 ± 60 kg m−3 to convert volume change to mass change is appropriate for a wide range of conditions. For short time intervals (≤3 yr), periods with limited volume change, and/or changing mass balance gradients, the conversion factor can however vary from 0–2000 kg m−3 and beyond which requires caution when interpreting glacier mass changes based on geodetic surveys.
Cell Proliferation of the Primary Tumor Predicts Ipsilateral Axillary Node Disease in Elderly Breast Cancer Patients
Authors: Silvestrini Rosella , Martelli Gabriele , Miceli Rosalba , Agresti Roberto , Veneroni Silvia , Daidone Maria Grazia
Published: January 2013

The present study investigated whether tumor markers such as cell proliferation and steroid receptor status, which have been shown to have relevance for important endpoints (relapse-free and overall survival), can also predict axillary disease in elderly patients with breast cancer. We evaluated 351 consecutive elderly women with breast cancer ≥70 years of age with estrogen receptor (ER)-positive tumors with no palpable axillary nodes, for whom information on cell proliferation determined by the 3H-thymidine labeling index (TLI) and progesterone receptor (PgR) was available. Patients underwent quadrantectomy (70.1%) or quadrantectomy plus radiotherapy (29.9%) without axillary node dissection, followed by adjuvant tamoxifen for at least 2 years. Univariable (cumulative incidence curves) and multivariable analyses (Fine and Gray models) were carried out. After a median follow-up of 16 years, ipsilateral axillary relapse was not related to PgR status but was strongly associated with tumor cell proliferation in both small (pT1) and large (pT2-4b) tumors. Axillary relapse cumulative incidence increased from 1% in patients with low-TLI (≤3%), PgR-positive and pT1 tumors to a maximum of 20% in patients with high-TLI, PgR-negative and pT2-4b tumors. Tumor cell proliferation, determined by TLI at primary surgery, is an important predictor of axillary relapse in elderly ER-positive breast cancer patients and could help to identify patients who should undergo axillary surgery.
Vulnerability in Disasters
Authors: Krishnan Sneha
Published: January 2013

The elderly, the young and the sick are often the most vulnerable in times of flooding. The potential for water-borne diseases in the early stages of a disaster is high, but with the intervention of effective water and sanitation practices this can be greatly reduced or prevented. Special attention paid to the specific needs of the vulnerable population is essential. The floods in June 2012 in the Brahmaputra River in the state of Assam, North-east region of India devastated most states and led to huge displacement of population. This picture was shot at Sonitpur district, Assam.
On the Road to Nerja
Authors: Hills Charlotte
Published: January 2013

In between sunshine and showers on the road from Cordoba to Nerja, Spain. A spectacular but fleeting rainbow appeared moments later. This, with the golden fields and dark grey sky, produced a very surreal colour palette to a usually dull and arid landscape.
Radiating Joy
Authors: Prinzl Marlies
Published: January 2013

A bunch of cheerful boys. They were totally playing it up for the camera, indeed, that was something I noticed frequently during the walk through this poor area of Vasant Vihar: the children were keen on being photographed. They were posing, but I still love this image for the sheer raw energy and happy smiles that radiate from these children’s faces. Although they are not the poorest of the poor – they don’t live on the streets, they aren’t orphans and, even if they would probably be considered underweight by Western standards, they aren’t starving – they do live in poverty, in shabby homes and with probably no more than a change or two of clothes. And yet, the delight in their faces gives a feeling of hope. If children aren’t happy like this, where would we be in this world?
Florística e análise de similaridade de espécies arbóreas da mata da Praia do Totó, Pelotas, RS, Brasil
Authors: Venzke Tiago Schuch , Ferrer Rogério Soares , Costa Maria Antonieta Décio da
Published: January 2013

http://dx.doi.org/10.5902/198050987548O levantamento florístico de espécies arbóreas foi realizado em uma mata de restinga no município de Pelotas, Rio Grande do Sul, Brasil. O local de estudo é conhecido como Mata da Praia do Totó e compreende um remanescente formado por ambientes de matas de restinga arenosa e turfosa. Foi amostrado um total de 65 espécies nativas compreendendo 51 gêneros distribuídos em 34 famílias.A família que apresentou o maior número de espécies foi Myrtaceae com dez espécies, seguida de Salicaceae e Rubiaceae. Os gêneros mais representativos foram Myrsine e Eugenia, respectivamente com quatro e três espécies. A análise de similaridade amostrou que a mata arenosa é floristicamente relacionada com florestas ciliares e de encosta e a mata turfosa com outras florestas localizadas em áreas de saturação hídrica permanente do solo. A riqueza de espécies do local é elevada para matas de restinga no Rio Grande do Sul, provavelmente pela influência de florestas situadas na Serra dos Tapes e pela diversidade de ambientes que compõem a área de estudo.
Níveis crescentes de saturação por bases e desenvolvimento inicial de teca em um latossolo de textura média
Authors: Favare Lilian Guimarães de , Guerrini Iraê Amaral , Backes Clarice
Published: January 2013

http://dx.doi.org/10.5902/198050987551A teca é uma espécie florestal de alto valor comercial, porém, o pouco conhecimento do comportamento desta espécie em relação à acidez do solo é um fator importante que pode limitar o seu cultivo. O objetivo deste trabalho foi avaliar o efeito da elevação da saturação por bases do solo sobre o desenvolvimento inicial da teca (Tectona grandis L.f.). O experimento foi conduzido em estufa, em recipientes plásticos com capacidade de 50L. O delineamento experimental utilizado foi inteiramente casualizado, com cinco tratamentos e quatro repetições. Os tratamentos constituíram-se de: saturação por bases naturais do solo e os demais tratamentos com 20, 40, 60 e 80 % de saturação. A correção do solo favoreceu todas as características de crescimento avaliadas nas plantas de teca. A calagem afetou positivamente a absorção de N, P, K, Ca, Mg, B, Cu e Fe. A exigência nutricional da espécie obedeceu a seguinte ordem decrescente: N > Ca > K > Mg > P > S > Fe > Mn > B > Zn > Cu. Saturações por bases estimadas de 70 % proporcionaram maior desenvolvimento das plantas.
Influência da posição das miniestacas na qualidade de mudas de cedro australiano e no seu desempenho inicial no pós-plantio
Authors: Ferreira Daniele de Alvarenga , Barroso Deborah Guerra , Silva Mírian Peixoto Soares da , Souza Juliana Sobreira de , Freitas Teresa Aparecida Soares de , Carneiro José Geraldo de Araújo
Published: January 2013

http://dx.doi.org/10.5902/198050987553O cedro australiano, originário da Austrália, adaptou-se muito bem no Brasil, que apresenta condições adequadas para o seu desenvolvimento, sobretudo no sul da Bahia e em toda a região sudeste. Porém, os plantios são irregulares e as sementes são insumo limitante, por sua sazonalidade de oferta e curta viabilidade. A finalidade deste estudo foi avaliar a qualidade das mudas obtidas de miniestacas apicais, intermediárias e basais com 6 cm de comprimento oriundas de brotos de minicepas de Toona ciliata cultivadas em minijardim multiclonal em canaletões e o crescimento inicial das mudas no pós-plantio. Foi implantado um minijardim multiclonal em canaletões, contendo um total de 284 minicepas. A partir da parte aérea das mudas recepadas para formação das minicepas, foram produzidas miniestacas de diferentes posições. Na expedição do setor de enraizamento foram coletados dados de massa seca da parte aérea e do sistema radicular, comprimento, diâmetro, número de raízes adventícias e sobrevivência. A altura e diâmetro das mudas foram monitorados quinzenalmente, a partir de 80 dias, após o estaqueamento. Ao final do ciclo de produção, as mudas foram avaliadas com relação à massa seca da parte aérea e do sistema radicular, número, diâmetro e comprimento das raízes. Para avaliar as mudas após o plantio, 30 % das mudas foram transferidas para vasos de 3,8 L, onde foram avaliadas em altura e diâmetro do colo e, aos 60 dias, em massa seca do caule, folhas e raízes. As mudas provenientes das miniestacas basais, na expedição da fase de enraizamento, apresentaram os maiores valores de altura e diâmetro, não se diferenciando das intermediárias com relação ao diâmetro do colo. Não houve diferenças com relação à massa seca da parte aérea e número, massa seca, comprimento total e diâmetro das raízes adventícias das mudas em função do tipo de miniestacas. Após a transferência das mudas para a casa de vegetação, a sobrevivência foi alta, com média de 94,7 % para apicais, 96,3 % para intermediárias e 96,6 % para basais. Aos 60 dias após o plantio, apesar das diferenças observadas no diâmetro e altura das mudas ao final da fase de viveiro, não houve diferença no crescimento em altura, diâmetro e massa seca do caule, folhas e sistema radicular, em função dos tratamentos.
Sazonalidade do incremento em diâmetro do tronco de árvores de Eucalyptus grandis pelo uso de dendrômetros
Authors: Junior Carlos Roberto Sette , Filho Mario Tomazello , Lousada José Luis , Laclau Jean Paul
Published: January 2013

http://dx.doi.org/10.5902/198050987557O presente trabalho teve como objetivo avaliar a sazonalidade do incremento em diâmetro do tronco de árvores de Eucalyptus grandis e sua relação com as variáveis climáticas e de fertilização nitrogenada e com lodo de esgoto. As árvores foram plantadas no espaçamento de 3 x 2 m e fertilizadas com nitrogênio (plantio, 6, 12, 18 meses) e lodo de esgoto (plantio e 8 meses), sendo selecionadas 20 árvores de eucalipto por tratamento, de acordo com a distribuição de área basal do povoamento, instalados dendrômetros de aço no DAP e mensurado o incremento em diâmetro de fevereiro/2006 a fevereiro/2008. Os resultados permitem concluir que houve efeito das variáveis climáticas na sazonalidade do incremento em diâmetro do tronco das árvores de eucalipto, sendo observado um período de defasagem (lag) de 28 dias para a resposta das árvores em relação às variáveis climáticas. Com relação ao efeito da fertilização, determinou-se que o incremento em diâmetro do tronco foi maior nas árvores de eucalipto com tratamento de lodo de esgoto em relação à adubação mineral com nitrogênio.
Modelagem do crescimento de clones de Eucalyptus usando o modelo de Chapman-Richards com diferentes distribuições simétricas dos erros
Authors: Filho Luiz Medeiros de Araujo Lima , Silva José Antônio Aleixo da , Cordeiro Gauss Moutinho , Ferreira Rinaldo Luiz Caraciolo
Published: January 2013

http://dx.doi.org/10.5902/198050987558Objetivou-se neste trabalho estimar o crescimento em altura de clones de Eucalyptus usando o modelo de Chapman-Richards, considerando para os erros as distribuições: normal, t de Student (t) e Cauchy. Foram utilizados dados de clones de híbrido entre Eucalyptus urophylla x Eucalyptus tereticornis x Eucalyptus pellita (polinização controlada), do Módulo de Experimentação Florestal para o Polo Gesseiro do Araripe, implantado em 2002. Utilizaram-se 83 árvores cujas alturas foram medidas durante seis anos e meio. Os parâmetros do modelo de Chapman-Richards foram obtidos maximizando a função de log-verossimilhança. Para comparação dos modelos foram utilizados os critérios de informação de Akaike (CIA) e Bayesiana (CIB) e o erro percentual absoluto médio (EPAM). O modelo usando a distribuição t de Student com 2 graus de liberdade (t2) obteve menores valores de CIA e CIB enquanto que o modelo de Cauchy obteve menor valor para o EPAM. Os resultados indicam que o modelo, considerando distribuição t para os erros, apresentou melhores estimativas do crescimento em altura de clones híbrido de Eucalyptus no Polo Gesseiro de Pernambuco.
Influência das características anatômicas e do teor de extrativos totais da madeira de Eucalyptus grandis W. Hill ex Maiden na qualidade da colagem
Authors: Albino Vanessa Cristina do Sacramento , Mori Fábio Akira , Mendes Lourival Marin
Published: January 2013

http://dx.doi.org/10.5902/198050987561O trabalho teve como objetivo caracterizar anatomicamente e quantificar os extrativos totais em diferentes posições de toras de Eucalyptus grandis W. Hill ex Maiden com 18 anos de idade e avaliar a influência dessas características sobre a resistência ao cisalhamento e percentagem de falhas na madeira de juntas coladas com adesivo termoendurecedor resorcinol-formaldeído. Foram preparadas lâminas histológicas para o estudo anatômico e determinou-se o teor de extrativos totais. A preparação das juntas coladas foi feita de acordo com a norma ASTM D 2339-98(2000). Utilizou-se o coeficiente de correlação de Pearson, a 1 % de probabilidade pelo teste t de Student, para avaliar as correlações existentes entre as características anatômicas e teor de extrativos com a qualidade das juntas coladas. Verificou-se que houve correlação entre resistência ao cisalhamento com as seguintes características: diâmetro do vaso, espessura da parede, largura e comprimento da fibra, largura do raio e teor de extrativos totais. E, em relação à percentagem de falhas na madeira, houve correlação entre esta com as seguintes características: frequência de vasos, espessura do lume da fibra, frequência e altura do raio. Tanto no sentido radial quanto no sentido longitudinal das toras, houve variação dos valores encontrados para a mensuração dos elementos anatômicos, quantidade de extrativos totais, resistência ao cisalhamento e percentagem de falhas na madeira.
Balanço nutricional, produção de óleo essencial e madeira de Corymbia citriodora Hill & Johnson com aplicação de lodo de esgoto e fertilizante mineral
Authors: Silva Paulo Henrique Müller da , Poggiani Fabio , Ferraz Alexandre de Vicente , Sixel Ricardo Michael de Melo , Brito José Otavio
Published: January 2013

http://dx.doi.org/10.5902/198050987563O Corymbia citriodora é uma das espécies florestais mais difundidas no Brasil, sendo um dos motivos a diversidade de uso da espécie, pois produz madeira de qualidade e as folhas podem ser utilizadas para produção de óleo essencial. Entretanto, é uma espécie que não tem muitos estudos relacionados ao efeito do manejo no balanço nutricional. O objetivo deste trabalho foi avaliar a produção de biomassa e o balanço nutricional no sistema convencional de produção de óleo essencial e madeira de Corymbia citriodora com a aplicação de lodo de esgoto. O delineamento experimental utilizado foi em blocos casualizados, com quatro repetições e dois tratamentos, sendo eles: 1 - Fertilização com 10 t ha-1 (base seca) de lodo de esgoto, complementado com K+B, e 2 - Fertilização mineral. Foi avaliada a produção de biomassa aérea das árvores e dos respectivos componentes (folha, galho, casca e lenho), a exportação de nutrientes via colheita da folhas, a produção de óleo essencial e da madeira aos quatro anos de idade. Observou-se que as árvores fertilizadas com lodo produziram 20 % mais folhas durante o ciclo de produção, o que resultou em maior produção de óleo essencial. Além disso, o tratamento com a aplicação do lodo produziu 14,2 t ha-1 ano-1 de biomassa lenhosa, que foi 27 % superior ao tratamento com fertilização mineral. Para ambos os tratamentos o balanço do N foi negativo, sendo que a exportação de N no tratamento com aplicação de lodo de esgoto (-45 kg ha-1) foi 4 vezes menor que a observada no tratamento com fertilização mineral (-185 kg ha-1). Com o presente estudo pode-se concluir que a aplicação de lodo de esgoto em plantios de Corymbia citriodora beneficia a produção de biomassa foliar, óleo essencial e madeira, além de propiciar melhor balanço nutricional.
Educação socioambiental, imaginário e Artes Visuais
Authors: Ormezzano Graciela René , Poma Silviani Teixeira
Published: January 2013

http://dx.doi.org/10.5902/198464443499 Este artigo surge de uma pesquisa bibliográfica que opta pela cosmovisão estética proposta por Maffesoli e fala do imaginário social como fundamento para o estudo. Ainda faz um breve levantamento de algumas políticas públicas educacionais que favorecem a educação ambiental e a transversalidade e, por fim, discute a relevância das artes visuais no processo de ensino-aprendizagem transdisciplinar realizando uma proposta metodológica que se considera apta a ser desenvolvida nos diversos níveis de ensino formal ou na educação não formal. O modo de execução sugerido está fundamentado no emprego de oficinas como metodologia pedagógica, juntando as artes visuais dos vários campos do saber com os quais pode se relacionar ao tratar o tema da educação socioambiental. A proposta trata da necessidade de se voltar para a experiência inventiva com a finalidade de (re)descobrir a ação de educar e de educar-se sem perder de vista a totalidade. Busca o sentido da vida em sociedade, transformando a percepção humana do Cosmos, respeitando o ambiente natural e a complementaridade das múltiplas culturas. Palavras-chave: educação socioambiental, imaginário, artes visuais.
Pensando sobre a aprendizagem de conceitos em sala de aula
Authors: Carlino Eliana Prado
Published: January 2013

http://dx.doi.org/10.5902/198464444476 Muitas são as teorias de aprendizagem a subsidiar a atividade do professor, quando ele se propõe a trabalhar um determinado conhecimento ou conceito em sala de aula. A partir desses referenciais teóricos que circulam nos espaços educacionais e embasam, ainda que implicitamente, o fazer docente, surgiu nossa preocupação com o processo de ensino e as relações estabelecidas com a/pela linguagem na aprendizagem de conceitos. Procuramos, neste artigo, explicitar o movimento que ocorre por meio das inter-relações envolvendo alunos, professores e conhecimentos. Assim, apresentamos aqui a dinamicidade de que se reveste o trabalho de elaboração conceitual, no qual os sentidos produzidos nem sempre são aqueles previstos na intencionalidade do professor. Essa não convergência, contudo, não torna essa produção equivocada ou incorreta, mas faz parte da dinâmica que caracteriza a linguagem e a produção de sentidos. Para evidenciar esse processo, embasamos nossas considerações em Vygotsky e Bakhtin, por terem o signo e a linguagem como centralidade em suas elaborações teóricas e por considerarem a dialogia como princípio das interações humanas. Palavras-chave: conceito; linguagem; sentido
Produções do invisível: considerações sobre o tempo e a formação de professores
Authors: Dalmaso Alice , Sangoi Deisi
Published: January 2013

http://dx.doi.org/10.5902/198464444493 O presente texto se propõe a abordar, mesmo que brevemente, a temática da invenção no âmbito da formação de professores. Para tanto, faremos um apanhado das contribuições de Virgínia Kastrup a esse respeito, trazendo a questão do tempo – através da problematização de duração, de Henri Bergson – e seu emprego na temática da formação. A partir disso, tentaremos desconstruir um olhar de referência identitária na contemporaneidade para modos de existência que se percebem múltiplos e abertos. Na processualidade que se trata em explicar, nos movimentos inventivos que funcionam com ela, o tempo é considerado como expressão da dimensionalidade do ser individuando-se. Ou seja, durar refere-se a uma imediatidade do ser, do tempo de ser, que é modulável, mutante, sempre em devir, sempre em criação. Na construção de produzir um corpo que abandona uma referência identitária – que diverge com a transformação de si – inevitavelmente reportamo-nos à relação da ideia de tempo como duração com a operação de individuação de Gilbert Simondon. É do intercruzamento destes conceitos, e sua possível ressonância no debate que concerne a políticas formativas, que se pode desenvolver um olhar do invisível a uma formação de professores, de aprendizes de outros modos de operar no mundo. A invenção como alavanca nos direciona a um campo de possibilidades de conceber e vivenciar um outro tempo (e espaço) que é ele mesmo produção de subjetividades, singularidades e diferenças. Palavras-chave: tempo, individuação, formação de professores.
Cultura escrita: aprender a ler e escrever na escola
Authors: Bolzan Doris Pires Vargas , Santos Eliane Aparecida Galvão dos , Powaczuk Ana Carla Hollweg
Published: January 2013

http://dx.doi.org/10.5902/198464446095 Este texto discute os aspectos formais da escrita e da leitura no contexto da sala de aula, destacando a importância do protagonismo dos estudantes, favorecendo sua autoria como escritores e leitores a partir da cultura escrita. Compreendemos que é indispensável que a escola tenha uma visão prospectiva em relação às aprendizagens dos estudantes, ou seja, que valorize suas poten-cialidades, levando em conta a cultura na qual estão inseridos. Colocamos em relevo o papel do alfabetizador no processo de organização do trabalho pedagógico, voltado ao ensino e à aprendizagem da lectoescrita dos estudantes nos anos iniciais do Ensino Fundamental. Nesse sentido, destacamos que a organização do ensino exige investimento docente em direção ao aprimoramento dos fazeres e saberes que incidem na organização do trabalho pedagógico, demarcando um longo caminho a percorrer, de modo a permitir a assunção do protagonismo pedagógico. Palavras-chave: alfabetização; cultura escrita; atividades diversificadas.
Escribir en la Universidad
Authors: Beraza Miguel Zabalza
Published: January 2013

http://dx.doi.org/10.5902/198464446251 Escribir en la Universidad constituye tanto una necesidad básica como un propósito formativo de largo alcance. Una de las características básicas de la institución universitaria es que precisa de la escritura como herramienta comunicacional y como recurso de estimulación intelectual. Tras establecer los rasgos básicos de la naturaleza y tipologías de escritura académica, el artículo analizar el papel que juega la escritura tanto para los estudiantes universitarios (escribir para aprender) como para el profesorado (escribir para planificar, para reflexionar, para documentar lo que se hace) y para ambos colectivos, profesores y estudiantes, conjuntamente (escribir para investigar). Finalmente, yendo más allá de lo que la escritura tiene de herramienta académica, se concluye con una visión más lúdica y creativa: la escritura como placer y disfrute personal. Palabras clave: enseñanza universitaria; escritura académica; competencia de expresión escrita; diarios de clase; documentación e investigación docente.
Editorial – Revista Educação
Authors: Bellochio Cláudia Ribeiro , Bolzan Doris Pires Vargas
Published: January 2013

http://dx.doi.org/10.5902/198464447584