Spatial Distribution Of Groups Research Articles

Low latitude habitat use patterns of a recovering population of humpback whales

The coast of Brazil is an important low latitude nursery ground for humpback whales (Megaptera novaeangliae). The number of humpback whales in this region has increased and its population is reoccupying areas where it has been depleted during the whaling period. The goal of this study was to conduct land-based observations during 2014 and 2015 to characterize patterns of habitat use and relative abundance of humpback whales that migrate to one of these reoccupation areas: Serra Grande, Bahia state. The observed mean group size was 2.12 ± 0.96 individuals and did not vary through the reproductive season nor between years. Dyads (32.9%) and singletons (26.7%) were more frequently observed, and groups with calves represented 21.2% of the sightings. The mean number of whales counted per hour increased from 2014 (3.44 ± 3.35) to 2015 (5.12 ± 4.18). Habitat use varied during the season; whales used shallower waters closer to shore as the season progressed. The spatial distribution of groups with calves was dependent on the presence and number of escorts. Spatial segregation of groups with calves closer to shore is a key factor in understanding the overall distribution of whales in the area, suggesting that social strategies are affected by environmental factors, as seen in other wintering grounds. Small-scale studies from land-based stations, in areas such as this where there is no previous knowledge about the species, are cost effective. They provide information about the overall behavioural and spatial patterns while anthropogenic activity is still low, allowing habitat protection and management decisions before implementation and increase of human activities.

Engineering Chemical Functionality in Graphene

Graphene has attracted enormous attention due to its unique properties. Equally important is the ability to further tailor these properties through modification of select attributes such as surface chemistry, number of layers, sheet width, and edge structures. Manipulating the surface chemistry of graphene is important since the chemical composition strongly impacts the electronic properties as well as chemical reactivity both globally and locally. Precise control of the surface chemistry of graphene can also allow for subsequent surface procedures focused on band gap engineering, device fabrication and sensor applications. Given the strong impact of adsorbates, global chemical modification provides opportunities towards greater control over the properties of graphene films. Control over the spatial distribution of these groups provides an even greater functionality in that the local graphene reactivity can be manipulated, opening up a wealth of opportunities in biosensing, plasmonics, catalysis, smart surfaces, and heterojunction devices. This work demonstrates the ability to manipulate the chemistry of graphene while regulating the spatial distribution of various functional groups on the surface. Spatial control over structural and chemical changes is characterized through micro (m-Raman and high-resolution x-ray photoelectron spectroscopy (XPS) mapping and electrical measurements are used to determine how local changes in chemistry influence the electronic properties. Lastly, we show that the resulting chemical moieties can be used to manipulate the local surface reactivity of graphene, enabling programmable, site-specific electrochemical deposition. These findings demonstrate the ability to tailor the locality of the surface chemistry on graphene surfaces opening up a wide range of reactivity studies and synthesis capabilities, such as programmable material deposition.

English

This article aims to analyze the phenomena of urban segregation and social integration in the Palestinian refugee camps. The arguments are based on a theoretical basis as well as findings from the author’s fieldwork taken where he used to live in the Gaza refugee camp. The main argument of this paper claims that residential segregation and the creation of informal settlements in the city boundaries are exclusively associated with cultural, urban poverty, socio-political and historical aspects that reflect on the urban fabric of the camps. The author’s proposes that the roots of the phenomena of urban segregation and integration are an outcome of the constructed social strata, which can be theorized within two interrelated socio-political new situation of the refugees, and the historical, identity aspects; one defines them as refugees who should preserve their right and identity to go back home where the urban camp and social structure and fabric reflected this situation, and the other identifies the Israeli regime, social obstacles and life conditions in the received society as the negative factors that prevented the refugees to have the opportunity of assimilation. Additionally, the paper suggests that the ‘traditional approach’ in urban geography, based on Park’s premise, as having the basic hypothesis that the greater the degree of difference between spatial distribution of groups within the urban context, the greater their social distance from the other. This approach, in essence, views the integration process of the Palestinian refugees and the resettlement goals that the refugees struggled to achieve it temporarily to have the same opportunities as assimilated citizens in the West Bank and Gaza. The ecological approach of the Chicago School will be use to study the integration and assimilation phenomena. Key words: Chicago School of Sociology, Palestinian refugees camps, Palestinian refugees, social distance, succession, zone of transition.

Análise multivariada de atributos pedológicos e fitossociológicos aplicada na caracterização de ambientes de cerrado no norte de Minas Gerais

O Cerrado é uma das principais regiões de expansão agropecuária do país, entretanto a fragilidade dos seus ecossistemas restringe a capacidade de suporte a muitas das atividades agrícolas e compromete a preservação da sua biodiversidade. O objetivo deste estudo foi definir padrões locais de características edáficas e vegetacionais, em uma sub-bacia em Rio Pardo de Minas (MG), como base para o planejamento local de uso sustentável. Para tal, foram utilizadas técnicas de levantamento fitossociológico e de solos associadas à análise estatística multivariada, dendrograma e análise de componentes principais, de forma a correlacionar distribuição espacial de grupos de espécies e atributos edáficos. Os resultados indicaram a ordenação dos ambientes em dois grupos, em função da natureza dos materiais de origem: arenítico-quartzítico e sedimentos argilo-arenosos e argilosos. A seleção de variáveis pela análise multivariada foi capaz de discriminar os ambientes representados no levantamento fitossociológico. Os padrões identificados pelos agricultores corresponderam, em geral, às variações nos parâmetros florísticos e fitossociológicos e aos atributos edáficos, entre estes a densidade absoluta, a área basal e o índice de diversidade; as frações granulométricas foram determinantes na diferenciação dos ambientes.