Tangible symmetry elements and space-group models to guide from molecular to solid-state composition

The ability to imagine symmetry and the spatial arrangement of atoms and molecules is crucial in chemistry in general. Teaching and understanding crystallography and the composition of the solid state therefore require understanding of symmetry elements and their relationships. To foster the student's spatial imagination, models representing a range of concepts from individual rotation axes to complete space groups have been designed and built. These models are robust and large enough to be presented and operated in a lecture hall, and they enable students to translate conventional 2D notations into 3D objects and vice versa. Tackling them hands-on means understanding them.

Optimal location of resources and Steiner symmetry in a population dynamics model in heterogeneous environments

The subject of this paper is inspired by Cantrell and Cosner (1989) and Cosner, Cuccu and Porru (2013). Cantrell and Cosner (1989) investigate the dynamics of a population in heterogeneous environments by means of diffusive logistic equations. An important part of their study consists in finding sufficient conditions which guarantee the survival of the species. Mathematically, this task leads to the weighted eigenvalue problem \(-\Delta u =\lambda m u \) in a bounded smooth domain \(\Omega\subset \mathbb{R}^N\), \(N\geq 1\), under homogeneous Dirichlet boundary conditions, where \(\lambda \in \mathbb{R}\) and \(m\in L^\infty(\Omega)\). The domain \(\Omega\) represents the environment and \(m(x)\), called the local growth rate, says where the favourable and unfavourable habitats are located. Then, Cantrell and Cosner (1989) consider a class of weights \(m(x)\) corresponding to environments where the total sizes of favourable and unfavourable habitats are fixed, but their spatial arrangement is allowed to change; they determine the best choice among them for the population to survive. In our work we consider a sort of refinement of the result above. We write the weight \(m(x)\) as sum of two (or more) terms, i.e. \(m(x)=f_1(x)+f_2(x)\), where \(f_1(x)\) and \(f_2(x)\) represent the spatial densities of the two resources which contribute to form the local growth rate \(m(x)\). Then, we fix the total size of each resource allowing its spatial location to vary. As our first main result, we show that there exists an optimal choice of \(f_1(x)\) and \(f_2(x)\) and find the form of the optimizers. Our proof relies on some results in Cosner, Cuccu and Porru (2013) and on a new property (to our knowledge) about the classes of rearrangements of functions. Moreover, we show that if \(\Omega\) is Steiner symmetric, then the best arrangement of the resources inherits the same kind of symmetry. (Actually, this is proved in the more general context of the classes of rearrangements of measurable functions.

Disempowering Traditional Spatial Arrangement of Dayak Community: A Case Study of Tumbang Marikoi Village, Central Kalimantan, Indonesia

The rapid industrialization in the last decades significantly changed the traditional spatial arrangement in Central Kalimantan Island. The indigenous community’s traditional forest lands management and ownership were transferred to oil palm plantations and mining corporations. Therefore, it disempowered the traditional spatial arrangement by changing the community’s living conditions and transforming their livelihood sources from primary (forests) to secondary and tertiary. The disempowered traditional spatial arrangement of the Tumbang Marikoi village community includes a living area with rivers, forests, and dwellings. They access the forest through the village Kahayan Hulu and the Marikoi River. There is no power grid in Marikoi Village, making them depend on a solar-powered energy generation facility for their daily activities, including gardening, gathering forest products, hunting, mining gold, and fishing. This study applied the phenomenological method to explain the traditional spatial disempowerment in Marikoi Village, Central Kalimantan, following corporate plantation powers and mining activities. The results indicated that the palm plantations affected the Dayak community's living space and daily life. Furthermore, the ownership and management of their customary land, enhancing their economic, social, cultural, and religious life, was transferred to large plantations. As a result, the community’s traditional spatial arrangement was disempowered through river silting from soil drilling, cloudy river water, flooding, distant land for income (selling honey, vegetables, rattan, herbal medicine, and other forest wealth), farming restrictions by clearing land and losing sacred areas and ancestral rituals.

Sites of Violence, Sites of Peace, Sites of Justice: Transforming the Relational Landscape of Yogyakarta

The collaborative “Sites of Violence, Sites of Peace” project seeks to transform the relational landscape of Yogyakarta by enabling new intergenerational conversations about the 1965 politicide in Indonesia and further injustices with other marginalized communities. This community-engaged project developed walking tours of (largely unacknowledged) sites of historic violence: a colonial fort turned national museum, a derelict office building, a refurbished bank. Through these tours, sites of past suffering are activated by unheard survivor testimonies, making visible historical injustice and its contemporary and enduring significance. Unsettling the dominant spatial arrangement of Yogyakarta, the tours rewrite the city as a space where injustice and persecution are experienced. Crucially, the tour is also a relational encounter, facilitating intergenerational conversations that challenge social and political exclusionary norms. It, thereby, enables a form of relational justice, which requires active involvement from fellow citizens, not solely redress from the state.

Texture-like representation of objects in human visual cortex

The human visual ability to recognize objects and scenes is widely thought to rely on representations in category-selective regions of visual cortex. These representations could support object vision by specifically representing objects, or, more simply, by representing complex visual features regardless of the particular spatial arrangement needed to constitute real world objects. That is, by representing visual textures. To discriminate between these hypotheses, we leveraged an image synthesis approach that, unlike previous methods, provides independent control over the complexity and spatial arrangement of visual features. We found that human observers could easily detect a natural object among synthetic images with similar complex features that were spatially scrambled. However, observer models built from BOLD responses from category-selective regions, as well as a model of macaque inferotemporal cortex and Imagenet-trained deep convolutional neural networks, were all unable to identify the real object. This inability was not due to a lack of signal-to-noise, as all of these observer models could predict human performance in image categorization tasks. How then might these texture-like representations in category-selective regions support object perception? An image-specific readout from category-selective cortex yielded a representation that was more selective for natural feature arrangement, showing that the information necessary for object discrimination is available. Thus, our results suggest that the role of human category-selective visual cortex is not to explicitly encode objects but rather to provide a basis set of texture-like features that can be infinitely reconfigured to flexibly learn and identify new object categories.

VOLUMETRIC PRODUCTION OF EUCALYPTUS SPP. CLONES UNDER DIFFERENT SPACING IN A SEVERE DROUGHT PERIOD IN THE SEMI-ARID REGION OF PERNAMBUCO, BRAZIL

The adaptation of Eucalyptus clones in the Chapada of Araripe, PE, Brazil was observed after implementing experiments with fast-growing forests. This region has a high demand for alternative energy sources due to the Gypsum Pole, basically maintaining its energy matrix from the exploitation of Caatinga vegetation. Therefore, as a way to increase the gains in volumetric productivity in planting Eucalyptus spp. clones, it is important to understand which spacing levels provide the best competition between individuals. Thus, the objective of this study was to evaluate if the volumetric productivity of Eucalyptus spp. clones is affected by different spacing levels in stands implanted under severe weather conditions in Chapada of Araripe, PE, Brazil. The experiment was carried out at the Experimental Station of the Pernambuco Agronomic Institute (IPA) in the municipality of Araripina, PE, Brazil. Three Eucalyptus clones (C11, C39 and C41) with five spacing levels (2 m x 1 m, 2 m x 2 m, 3 m x 2 m, 3 m x 3 m and 4 m x 2 m) were arranged in a completely randomized design with factorial arrangement (3 x 5). The survival rate of the experiment was higher than 94%, even under conditions of water stress. The highest volume productivity was obtained with the C39 clone in the 2 m x 1 m spatial arrangement. The spatial arrangement strongly influences productivity. Even with the severe drought condition regulating productivity, the C39 clone showed MAI values of 15.92 m3 ha-1 year-1.

Orientation dependence of optical activity in light scattering by nanoparticle clusters

The optical properties of nanoparticle clusters vary with the spatial arrangement of the constituent particles, but also the overall orientation of the cluster with respect to the incident light. This...

Macrophage and Neutrophil Interactions in the Pancreatic Tumor Microenvironment Drive the Pathogenesis of Pancreatic Cancer

Despite modest improvements in survival in recent years, pancreatic adenocarcinoma remains a deadly disease with a 5-year survival rate of only 9%. These poor outcomes are driven by failure of early detection, treatment resistance, and propensity for early metastatic spread. Uncovering innovative therapeutic modalities to target the resistance mechanisms that make pancreatic cancer largely incurable are urgently needed. In this review, we discuss the immune composition of pancreatic tumors, including the counterintuitive fact that there is a significant inflammatory immune infiltrate in pancreatic cancer yet anti-tumor mechanisms are subverted and immune behaviors are suppressed. Here, we emphasize how immune cell interactions generate tumor progression and treatment resistance. We narrow in on tumor macrophage (TAM) spatial arrangement, polarity/function, recruitment, and origin to introduce a concept where interactions with tumor neutrophils (TAN) perpetuate the microenvironment. The sequelae of macrophage and neutrophil activities contributes to tumor remodeling, fibrosis, hypoxia, and progression. We also discuss immune mechanisms driving resistance to standard of care modalities. Finally, we describe a cadre of treatment targets, including those intended to overcome TAM and TAN recruitment and function, to circumvent barriers presented by immune infiltration in pancreatic adenocarcinoma.

SERVICE CENTRES IN RURAL DEVELOPMENT : A CASE STUDY OF JAUNPUR DISTRICT, UTTAR PRADESH

This paper attempts to deal with the identifying the service centers and calculation of the spatial arrangement with complementary area of service centres in Jaunpur district Jaunpur district of Uttar Pradesh. The study area is situated in Eastern Uttar Pradesh of the Middle Ganga Plain. The study is exclusively based on secondary data collected at block level from different offices. The centrality score has been calculated on the basis of three type of indices like functional centrality index, working population index and tertiary population index. There are 31 function or services selected judicially from five sectors (administrative, agricultural and financial, educational, health and transport and communication) to measure the centrality of service centre. The thissen polygon and berry breaking point method has been used for measure the complementary area. Total 88 service centres have been identified as first, second, third, fourth and fifth order service centre. The number of I, II, III, IV, and V order centres accounts for 43, 24, 16, 4, and 1 respectively.