Nest Structure Research Articles

Developing conservoltaic systems to support biodiversity on solar farms

Despite a booming renewable energy sector in Australia, there are few studies investigating the potential for land sharing between renewable energy and nature conservation. We introduce the concept of conservoltic systems, where solar energy and wildlife conservation can occur simultaneously. Habitat conversion is one of the leading threats to biodiversity globally (Fischer & Lindenmayer, 2007). Renewable energy initiatives such as large-scale solar, wind and hydroelectric power installations have recently boomed, requiring large areas of land for power generation. To offset decreasing land available for biodiversity and nature conservation, land sharing (i.e. using the same land for multiple purposes; Fischer et al., 2008) could maximise land value. Agrivoltaic systems (agriculture + voltaic [solar energy]) are one of the suggested multifunction land uses for renewable energy. In these systems, solar energy and agricultural practices coexist to produce beneficial outcomes for both industries, emerging to better meet the needs for multiple commercial-scale financial returns (Adeh et al., 2019; Dinesh & Pearce, 2016; Dupraz et al., 2011). No such scheme, however, exists for combining solar energy and wildlife conservation in Australia. Here, we introduce the concept of conservoltaic systems to identify and exploit opportunities to combine solar energy production and biodiversity conservation. Innovative design and management strategies on solar farms could contribute to nature conservation. Solar panels may provide suitable habitat and structural complexity for wildlife, including shelter from predators, perch or nesting structures and shading (Nordberg et al., 2021; Figure 1 and 2), which can be enhanced with appropriate management (e.g. targeted habitat restoration activities). Consequently, a few studies from Europe have identified opportunities to enhance pollinator biodiversity on large-scale solar parks (Blaydes et al., 2021, 2022; Montag et al., 2016). Clearly defining the required characteristics of conservoltaic sites and the management required for wildlife to benefit from such opportunities is urgent, especially given the current and rapidly increasing extent of solar farms worldwide (Agha et al., 2020; Nordberg et al., 2021). Furthermore, building solar farms on sites degraded by previous land uses, such as arable cropland or livestock grazing, especially in areas with low productivity, provides an opportunity to minimise land conversion while simultaneously increasing land value by creating habitat for local wildlife. We are, however, lacking research on appropriate locations, configurations and management schemes on solar farms to enhance biodiversity retention and recovery. We urgently require empirical data on wildlife use of solar farms and adjoining areas to successfully identify land sharing opportunities of hybrid landscape designs, or ‘conservoltaic’ systems. A collaborative approach across industry, land managers and research organisations is needed to facilitate land management schemes that promote energy production and conservation actions simultaneously (Moore-O'Leary et al., 2017). Eric J. Nordberg: Conceptualization (equal); writing – original draft (lead); writing – review and editing (equal). Lin Schwarzkopf: Conceptualization (equal); writing – original draft (supporting); writing – review and editing (equal). Open access publishing facilitated by University of New England, as part of the Wiley - University of New England agreement via the Council of Australian University Librarians. There is no raw data associated with this article.

TFEB Rearranged Renal Cell Carcinoma: Pathological and Molecular Characterization of 10 Cases, with Novel Clinical Implications: A Single Center 10-Year Experience.

To report our experience with the cases of TFEB rearranged RCC, with particular attention to the clinicopathological, immunohistochemical and molecular features of these tumors and to their predictive markers of response to therapy. We have retrieved the archives of 9749 renal cell carcinomas in the Institute of Urology, Peking University and found 96 rearranged RCCs between 2013 and 2022. Among these renal tumors, ten cases meet the morphologic, immunohistochemical and FISH characterization for TFEB rearranged RCC. The 10 patients' mean and median age is 34.9 and 34 years, respectively (range 23-55 years old), and the male to female ratio is 1:1.5. Macroscopically, these tumors generally have a round shape and clear boundary. They present with variegated, grayish yellow and grayish brown cut surface. The average maximum diameter of the tumor is 8.5 cm and the median 7.7 (ranged from 3.4 to 16) cm. Microscopically, the tumor is surrounded by a thick local discontinuous pseudocapsule. All tumors exhibit two types of cells: voluminous, clear and eosinophilic cytoplasm cells arranged in solid sheet, tubular growth pattern with local cystic changes, and papillary, pseudopapillary and compact nested structures are also seen in a few cases. Non-neoplastic renal tubules are entrapped in the tumor. A biphasic "rosette-like" pattern, psammomatous calcifications, cytoplasmic vacuolization, multinucleated giant cells and rhabdomyoid phenotype can be observed in some tumors. A few tumors may be accompanied by significant pigmentation or hemorrhage and necrosis. The nucleoli are equivalent to the WHO/ISUP grades 2-4. All tumors are moderately to strongly positive for Melan-A, TFEB, Vimentin and SDHB, and negative for CK7, CAIX, CD117, EMA, SMA, Desmin and Actin. CK20 and CK8/18 are weakly positive. In addition, AE1/AE3, P504s, HMB45 and CD10 are weakly moderately positive. TFE3 is moderately expressed in half of the cases. PAX8 can be negative, weakly positive or moderately-strongly positive. The therapy predictive marker for PD-L1 (SP263) is moderately to strongly positive membranous staining in all cases. All ten tumors demonstrate a medium frequency of split TFEB fluorescent signals ranging from 30 to 50% (mean 38%). In two tumors, the coincidence of the TFEB gene copy number gains are observed (3-5 fluorescent signals per neoplastic nuclei). Follow-up is available for all patients, ranging from 4 to 108 months (mean 44.8 and median 43.4 months). All patients are alive, without tumor recurrences or metastases. We described a group of TFEB rearranged RCC identified retrospectively in a large comprehensive Grade III hospital in China. The incidence rate was about 10.4% of rearranged RCCs and 0.1% of all the RCCs that were received in our lab during the ten-year period. The gross morphology, histological features, and immunohistochemistry of TFEB rearranged RCC overlapped with other types of RCC such as TFE3 rearranged RCC, eosinophilic cystic solid RCC, or epithelioid angiomyolipoma, making the differential diagnosis challenging. The diagnosis was based on TFEB fluorescence in situ hybridization. At present, most of the cases reported in the literature have an indolent clinical behavior, and only a small number of reported cases are aggressive. For this small subset of aggressive cases, it is not clear how to plan treatment strategies, or which predictive markers could be used to assess upfront responses to therapies. Between the possible options, immunotherapy currently seems a promising strategy, worthy of further exploration. In conclusion, we described a group of TFEB rearranged RCC identified in a large, comprehensive Grade III hospital in China, in the last 10 years.

Research-ready data: the C-Surv data model

Research-ready data (data curated to a defined standard) increase scientific opportunity and rigour by integrating the data environment. The development of research platforms has highlighted the value of research-ready data, particularly for multi-cohort analyses. Following stakeholder consultation, a standard data model (C-Surv) optimised for data discovery, was developed using data from 5 population and clinical cohort studies. The model uses a four-tier nested structure based on 18 data themes selected according to user behaviour or technology. Standard variable naming conventions are applied to uniquely identify variables within the context of longitudinal studies. The data model was used to develop a harmonised dataset for 11 cohorts. This dataset populated the Cohort Explorer data discovery tool for assessing the feasibility of an analysis prior to making a data access request. Data preparation times were compared between cohort specific data models and C-Surv.It was concluded that adopting a common data model as a data standard for the discovery and analysis of research cohort data offers multiple benefits.

Further Information about the Nest, Eggs and Nestlings of the Copper-Rumped Hummingbird Saucerottia tobaci from Venezuela

The Copper-rumped Hummingbird Saucerottia tobaci is a polyphyletic hummingbird with seven recognized subspecies. Nonetheless, the most information on its nesting behavior come from the island race S. t. erythronotos. This study aims to describe a nesting event of S. t. feliciae, the most widespread mainland subspecies, in order to provide detailed information on its nest structure, eggs and nestling development, as well as report information related to the nesting success (survival strategies, potential threats), based on observations carried out from August to October 2021 in northern Venezuela. Features of nest (composition, form, dimensions), eggs (appearance, dimensions, mass) and nestling development data from hatching to fledging time (body length, bill, wings, tail, and body mass) were all recorded in detail. The nest was an open saddle-type, cream in color, built of silky vegetable down, silky fibers of moth cocoon, mossy stuffs, pieces of lichen and spider’s web. Nest dimensions (mm): outer-cup depth: 40.7; inner-cup depth: 18.0; base-bed: 22.7; cup-rim thickness: 10.0–12.0; cup-rim length: 40.4; cup-rim wide: 18.4. Two oval-shaped eggs were laid inside, white in color, without spots or blots, smooth in texture, and non-glossy. Egg mass (0.6 ± 0 g; n = 2), egg length (13.95 ± 0.07 mm; n = 2), egg width (9.4 ± 0.14 mm; n = 2). Both eggs were incubated during 16 days. Nestlings were born almost completely naked, dark skin above, reddish beige below; bill yellow with the tip red and blunt; eyes closed. Nestling body mass at hatching (0.6 ± 0 g, n = 2), fledgling period (23 days). First feather barbs (day 10), eyes open (day 10), nestling totally feathered (day 16), and nestling body mass at fledging (4.7 g, n = 1). Survival strategies were nest camouflage, roof protection, female motionlessness, distraction displays and mobbing behavior. The nest was also close to a bumblebee nest and an artificial feeder. Potential threats included nest predators and heavy rains. This study introduces novel information on nesting behavior of a mainland subspecies and suggests that S. t. feliciae resembles S. t. erythronotos with slight differences in terms of nest construction, and eggs mass and length. Data on other nests, including those of other Venezuelan subspecies, are necessary to fully categorize the nesting behavior of this hummingbird in order to identify critical subspecific elements (e. g. nest materials, nestling´s food, human impact, additional nest predators and parasites) needed for its conservation in future.

Al distribution and structural stability of H-BEA zeolites at different Si/Al ratios and temperatures: a first-principles study.

Beta zeolites have been widely used in acid-catalyzed reactions because of their excellent properties. An in-depth study of the position, quantity, and distribution of beta zeolites substituted by Al is significant to understand the catalytic performance of the active site of zeolite catalysts. The distribution of Al in H-BEA and the structure of silanol nests in dealuminated BEA at different Si/Al ratios and synthesis temperatures were studied by the DFT method. T1, T2, T7, and T9 sites were chosen to be simulated. The synthesis temperature can change the distribution of Al and the proportion of T sites at different Si/Al ratios. The proportion of T7 and T9 is more than 70% at different Si/Al ratios of H-BEA and decreases with the synthesis temperature. T1 and T2 sites begin to appear when Si/Al < 20 and the proportion of T1 and T2 sites is less than 20%. When Si/Al < 8, the substitution energy of the AlSiAl structure, which has Si(2Al, 2Si) species, is obviously lower than that of the normal structure, which indicates that the Al-O-Si-O-Al species will appear in H-BEA. The Al(T7)Si(T5)Al(T9)Si(T5)Al(T7) and Al(T1)Si(T1)Al(T9) groups can not only stabilize H-BEA but also play an essential role in the formation of Si(2Al, 2Si) species. For dealuminated BEA zeolites, the silanol nest forms four hydrogen bonds through four silanols. The orientation of silanol groups in the silanol nest formed after dealumination at different T sites is different. The T7 and T9 sites in H-BEA are more likely to undergo dealumination. By contrast, the dealumination of the T1 and T2 sites is a challenge.

Finding Hierarchical Structure in Binary Sequences: Evidence from Lindenmayer Grammar Learning.

In this article, we explore the extraction of recursive nested structure in the processing of binary sequences. Our aim was to determine whether humans learn the higher-order regularities of a highly simplified input where only sequential-order information marks the hierarchical structure. To this end, we implemented a sequence generated by the Fibonacci grammar in a serial reaction time task. This deterministic grammar generates aperiodic but self-similar sequences. The combination of these two properties allowed us to evaluate hierarchical learning while controlling for the use of low-level strategies like detecting recurring patterns. The deterministic aspect of the grammar allowed us to predict precisely which points in the sequence should be subject to anticipation. Results showed that participants' pattern of anticipation could not be accounted for by "flat" statistical learning processes and was consistent with them anticipating upcoming points based on hierarchical assumptions. We also found that participants were sensitive to the structure constituency, suggesting that they organized the signal into embedded constituents. We hypothesized that the participants built this structure by merging recursively deterministic transitions.

Current Status of Breeding Population of Western Osprey in Abu Dhabi, United Arab Emirate

Western Osprey (Pandion haliaetus) is a resident breeding species in the United Arab Emirates (UAE). Osprey breed from December to March on offshore and nearshore islands and coastal sites across the country. Approximately 90% of the breeding population is found in Abu Dhabi Emirate, making it a critical area for conservation efforts. Due to its significance, Western Osprey has been listed as an Endangered (EN) species in the Abu Dhabi Redlist of Species. In 2023, an Emiratewide comprehensive survey was conducted, covering all coastal sites, as well as nearshore and offshore islands in Abu Dhabi. This was the first such comprehensive census of breeding Ospreys in Abu Dhabi. Data were collected using a customized mobile application with a focus on geo-referencing and photographing all nest structures. Of a total of 339 located nests across more than 60 coastal and island territories, 127 were active. Moreover, 44% (n=148) of all nests were observed on artificial platforms intentionally installed at different breeding territories to support nesting. Whereas 39% (n=133) were built naturally on ground and 17% (n=58) were observed on abandoned high-rise structures. The breeding population of osprey in the UAE is estimated to be 110 breeding pairs. The study established that current breeding population of Ospreys in Abu Dhabi Emirate stands at 127 breeding pairs. This stable breeding population of Osprey indicates the overall well-being of UAE’s coastal and marine environments. The Abu Dhabi Environmental Agency continues to monitor and enforce conservation measures to ensure the protection of this regionally important species and its habitats.

Quiet in the nest: The nest environment attenuates song in a grassland songbird

The nest environment may limit the ability of nest-bound birds to hear sounds from the outside world. In vocal learning species, such as humans and songbirds, it is vital for young animals to hear the voices of conspecific animals early in life. In songbirds, nest structure varies considerably across species, and the resulting impact on sound transmission may have consequences for vocal learning in nestlings. In this study, we tested the hypothesis that the nest environment attenuates song of Savannah Sparrows (Passerculus sandwichensis), grassland songbirds that build nests on the ground under cover of dense vegetation. We recorded live Savannah Sparrows singing at variable distances from 21 nests. We recorded songs using one microphone inside the nest (the typical position of a nestling) and another placed 1 m directly above the nest (a typical position of an adult). We found a substantial reduction in signal-to-noise ratio, where songs recorded inside the nest were an average of 11 dB lower than songs recorded directly above the nest. We estimate that the attenuation imposed by the nest reduced the maximum acoustic environment from 117.7 m (for recordings above the nest), to 78.6 m (for recordings within the nest), which is analogous to listening from a position 39.1 m farther away from the singer. Previous research estimated that song transmits up to 100 m in this species, so any adult male within 100 m of a young bird was previously considered a potential vocal tutor. By reducing the nestling acoustic environment from 100 m to 78.6 m, the number of male tutors available to nestlings is reduced by an average of 27%. Given the growing evidence that song learning begins very early in life, future research on vocal development should account for how the structural properties of the natal environment affect the songs that nestlings hear.

Результаты первой попытки привлечения пары орлана-белохвоста в искусственное гнездовье

Результаты первой попытки привлечения пары орлана-белохвоста в искусственное гнездовье

Convergent evolution of elaborate nests as structural defences in birds.

The pendent nests of some weaverbird and icterid species are among the most complex structures built by any animal, but why they have evolved remains to be explained. The precarious attachments and extended entrance tunnels characteristic of these nests are widely speculated to act as structural defences against invasion by nest predators, particularly tree-climbing snakes, but this hypothesis has yet to be systematically tested. We use phylogenetic comparative methods to investigate the relationship between nest structure and developmental period length, a proxy for offspring mortality, in weaverbirds (Ploceidae) and icterids (Icteridae), two bird families in which highly elaborate pendent nests have independently evolved. We find that more elaborate nests, particularly those with entrance tunnels, are associated with longer developmental periods in both families. This finding is robust to potentially confounding effects of body mass, phylogenetic relationships, nest location and latitude. Our results are consistent with the hypothesis that elaborate nest structures in birds can function as structural defences, resulting in lower offspring mortality and slower development. More generally, our findings suggest that constructing complex, protective structures may buffer against environmental hazards, reducing extrinsic mortality and contributing to the evolution of slower life histories in diverse animal lineages, even humans.

A Review of Ant Nests and Their Implications for Architecture

This paper discusses the latest progress in research on ant nests and explores innovative scientific concepts associated with underground ant nests from the perspective of bionics. The methods used by scholars to study the structure of ant nests and the interaction between the structure itself and the individual ants are investigated. The structural characteristics of the ant nest, its internal environment and ventilation characteristics are discussed in detail. In addition, this paper presents an innovative project in which the effect of underground ant nests on soil geotechnical properties and the effect of calcined ant nest soil powder, from the perspective of civil engineering, are addressed. Practical examples of the application of the structural and inter-relational aspects of subterranean ant nests in the field of architectural bionics are also provided, from the perspectives of construction, morphology, function and material. This review attempts to integrate civil engineering, architecture and biology, enlighten architects and biologists on converging their thinking, provide new ideas regarding underground ant colony nests, and provide references for long-term human habitation.

Differential abundance, composition and mesohabitat use by aquatic macroinvertebrate taxa in ponds with and without fish

Fish are known to pose strong effects on invertebrate abundance, species richness and assemblage structure. Littoral vegetation may play a crucial role as a refuge for invertebrates vulnerable to fish predation. We studied relative densities and taxonomic composition of water mites, aquatic beetles and bugs in large lake-like ponds with different fish status (fish-free and containing fish) and mesohabitats (emergent littoral vegetation and open water zone). The macroinvertebrate taxa differed in their responses to the fish presence and in mesohabitat preferences. The density and species richness of water mites were greater in fish-containing ponds, while no differences were found between littoral and open-water habitats. In contrast, beetles were far more numerous and species-rich in fish-free ponds and in littoral vegetation. Total densities of aquatic bugs were non-significantly higher in fish-containing ponds, and they preferred littoral areas, but species richness was independent of fish presence and mesohabitat. No statistical interactions between fish presence and the densities of individual macroinvertebrate groups in the littoral habitat were detected, indicating that their use of emergent littoral vegetation was not an antipredator response to fish. The assemblages of the three macroinvertebrate taxa exhibited nested structures of a different order, consistent with their species richness patterns. Our research stresses the importance of littoral vegetation for the distribution and abundance of aquatic insects; however, high fish presence may not affect or may even benefit ecologically important macroinvertebrate groups, such as water mites or bugs.

Nested spatial data structures for optimal indexing of LiDAR data

In this paper we present a flexible framework for creating spatial data structures to manage LiDAR point clouds in the context of spatial big data. For this purpose, standard approaches typically include the use of a single data structure to index point clouds. Some of them use a hybrid two-tier solution to optimize specific application purposes such as storage or rendering. In this article we introduce a meta-structure that can have unlimited depth and a custom, user-defined combination of nested structures, such as grids, quadtrees, octrees, or kd-trees. With our approach, the out-of-core indexing of point clouds can be adapted to different types of datasets, taking into account the spatial distribution of the data. Therefore, the most suitable spatial indexing can be achieved for any type of dataset, from small TLS-based scenes to planetary-scale ALS-based scenes. This approach allows us to work with overlapping datasets of different resolutions from different acquisition technologies in the same structure.

Understanding population movement and the evolution of urban spatial patterns: An empirical study on social network fusion data

Population movement has become one of the main vehicles for information transfer, factor flow, and resource allocation between cities. It is also considered as the main way to form the structure of regional organizational networks. This study analyzes the population movement channels, spatial patterns, and evolutionary mechanisms of the Yangtze River Delta with fused data (i.e., long-scale population migration and short-scale 48-hour population movement.), The results show that the population movement presents multipolar and decentralized evolutionary characteristics, and the population movement network in the Yangtze River Delta region has entered a complex network stage, showing a spider web-like convergent nested structure in terms of the population movement at a long time scale (2009–2017). The gravity model reveals that cost factors such as Spatio-temporal distance of population migration and boundary effects between urban nodes are complementary to the urban environment constituted by economic dynamics and social environment. Cultural exchange and regional integration are also quietly removing the cost-benefit constraints of population migration, thereby changing the mediating and diluting effects of the region. (1) Shanghai has not shown the great advantage of being the first city in the region; strong population movement mostly occurs within the provinces, with less cross-provincial movement; (2) population movement is more likely to occur between large and small cities, rather than between large or small cities, two cities with similar industrial structures are more likely to attract and connect with each other, (3) the institutional adhesion of administrative boundaries may have been diluted by the substitution effect of high housing prices, and (4) the stability of land property rights due to driving the regional integration process. This paper extends the vision and methodological practice of the gravity model to examine the network influence mechanism and analyze the mechanism of daily inter-city movements in two dimensions to provide policy insights for understanding the integration process in the Yangtze River Delta and the optimization strategy of regional metropolitan area integration.

Efficient DOA and Polarization Estimation for Dual-Polarization Synthetic Nested Arrays

To obtain a larger aperture for improving parameter estimation performance, we present a novel polarization sensitive array with dual-polarization synthetic nested structure, and then propose a low-complexity method for direction of arrival (DOA) and polarization estimation with two steps. There is a systematic procedure to determine the number and positions of antennas in each single-polarization subarray used for the synthetic nested array, in order to achieve more degrees of freedom (DOFs) and larger aperture for difference coarray with limited physical antennas. The increased DOFs of cross- and self-difference coarrays are quantitatively provided. To handle underdetermined parameter estimation with the resulting DOFs, the proposed method first estimates initial DOA and polarization state by using root-MUSIC and oblique projection operator, based on hole-free cross-difference coarray from cross-correlation matrix between subarrays. In the second step, holes in self-difference coarray, which is from autocorrelation matrix of single-polarization subarray, are filled with initial estimation. By exploiting both hole-free self- and cross-difference coarrays, an efficient search-based algorithm with initially estimated parameters is explored for refined estimation. The Cramér–Rao bound for the array and computational complexity of the method are provided. Simulation results are given to demonstrate the superior performance of the proposed array and method.

Ventilation Simulation in an Underground Ant Nest Structure of Camponotus japonicus Mayr

Ants are ancient animals on the earth and are known as excellent architects in the animal kingdom. The structure and performance of their nests are full of remarkable mysteries. At present, there are only a limited number of studies on the ventilation performance of underground ant nest structures. In this study, the nests of Camponotus japonicus Mayr were collected manually, and a three-dimensional digital model of the ant nest structure was obtained by the method of industrial CT scanning. The ventilation performance of the Camponotus japonicus Mayr nest structure was numerically simulated using the finite element analysis software, FLUENT. By changing the air inlet and outlet of the nest, the pressure changes inside the nest and the trajectory of the air flow inside the nest could be calculated and analysed, in order to explore the ventilation characteristics of the underground nest structure during natural ventilation. It was found that the ventilation environment inside the nest was stable, and that the external air flow had little effect on the life of the ants inside the nest.

Static Analysis of Underground Ant Nest Structures

Ants are known as nature’s master builders, constructing a wide range of nests, from simple nests with a single channel linking several chambers to ‘underground palaces’ that are several metres wide. However, there is a lack of understanding of the mechanical performance of underground ant nest structures. In this paper, two underground ant nest structures are obtained and digitally modelled by means of liquid paraffin wax infusion shaping, manual excavation and industrial CT scanning, and a finite element model of the underground ant nest structure is established by means of numerical simulation. By simulating people of different weights standing above the nests, the stress distribution characteristics of each chamber in the nests under different pressures are obtained, and the mechanical properties of the underground ant nest structures under static loads are investigated.

Effect of salinity on nest building behaviour in the nine-spined stickleback Pungitius sinensis.

The authors evaluated the adaptability of male nine-spined sticklebacks (Pungitius sinensis) at three salinity levels (0, 5 and 10psu) by comparing nest building success rates with nest structures. Successful nest building decreased as salinity increased. In addition, nests built in fresh water (i.e., 0 psu) were glued together, whereas those built in brackish water (5 and 10psu) broke easily and fell from the nest site to the gravel bottom. Based on these findings, the authors suggest that P. sinensis adapts to freshwater environments.

Differentiation and seasonality in suitable microsites of seed dispersal by an assemblage of omnivorous mammals

In endozoochorous seed dispersal, the ecological characteristics of each disperser determine the quantitative and qualitative aspects of the dispersal mechanism. To understand the role of different frugivores in multispecies seed dispersal networks, it is necessary to focus on the community structure and investigate where in the landscape seed deposition occurs. The aim of this research was to assess the quantitative and qualitative aspects of a mammalian endozoochorous seed dispersal network in a temperate forest ecosystem and identify the seasonal dispersal niche of each member of the assemblage. We hypothesized that differences among dispersers and seasons would occur in (H1) the proportion of scats that contain seeds, seed abundance in scats, and the number of seed species dispersed per scat, and in (H2) the probability of dispersing seeds to suitable microsites for germination of each species and seed abundance. We also hypothesized (H3) that the microhabitat variables of deposition sites would vary among dispersers, and (H4) that complementary structures would occur in terms of dispersers, dispersed species, and deposition sites. From summer (June–August) to autumn (September–November) in 2003 and 2004, we collected scats of five mammalian frugivorous species and recorded eight microhabitat variables at each deposition site in central Japan. We recorded the presence and number of seeds in scats and identified all seed at the species level. We considered a deposition site as suitable when the habitat type (interior forest, treefall gap, forest edge, and outside the forest) at a deposition site matched the microhabitat required for the for the dispersed species to germinate and survive as seedlings. A total of 341 scats containing seeds of 16 fleshy-fruited species were collected. Among these, 213 (62.5 %) scats were dispersed to suitable habitats (summer: 68.8 %, autumn: 54.8 %). We found that the seed abundance in the scat varied among dispersers and was higher in autumn (H1–2). The probability of dispersing seeds to suitable microsites switched among dispersers from summer to autumn (H2). The distinctive microhabitat variables and variation in microhabitat at deposition sites differed among dispersers across seasons (H3). Disperser-plant and disperser-deposition site networks were specialized and modular in structure compared to random networks during both seasons, but there was a less nested structure in summer compared to autumn (H4). The five mammal species showed differences and seasonality in seed dispersal niches. Because of these differences, these mammal species may play redundant and complementary roles in the seed dispersal network.

Topic Scaling: A Joint Document Scaling–Topic Model Approach to Learn Time-Specific Topics

This paper proposes a new methodology to study sequential corpora by implementing a two-stage algorithm that learns time-based topics with respect to a scale of document positions and introduces the concept of Topic Scaling, which ranks learned topics within the same document scale. The first stage ranks documents using Wordfish, a Poisson-based document-scaling method, to estimate document positions that serve, in the second stage, as a dependent variable to learn relevant topics via a supervised Latent Dirichlet Allocation. This novelty brings two innovations in text mining as it explains document positions, whose scale is a latent variable, and ranks the inferred topics on the document scale to match their occurrences within the corpus and track their evolution. Tested on the U.S. State Of The Union two-party addresses, this inductive approach reveals that each party dominates one end of the learned scale with interchangeable transitions that follow the parties’ term of office, while it shows for the corpus of German economic forecasting reports a shift in the narrative style adopted by economic institutions following the 2008 financial crisis. Besides a demonstrated high accuracy in predicting in-sample document positions from topic scores, this method unfolds further hidden topics that differentiate similar documents by increasing the number of learned topics to expand potential nested hierarchical topic structures. Compared to other popular topic models, Topic Scaling learns topics with respect to document similarities without specifying a time frequency to learn topic evolution, thus capturing broader topic patterns than dynamic topic models and yielding more interpretable outputs than a plain Latent Dirichlet Allocation.