Spatial exploration, dendrometric characteristics and prediction models of wood production in a stand of Acacia schaffneri in Durango, Mexico

Degraded vegetation is the result of a process that affects structural and functional characteristics. Tree species from the Acacia genus are very important to the ecosystem in semi-arid lands due to their participation in the recovery of highly degraded areas. One of the most important species among this genus is A. schaffneri. The status of a forest stand is determined according to its structure, including height, stratum and density. Remote sensing is a valuable method for estimating volumetric stocks and associated changes in forest populations over established periods of time. The objective of this research was to estimate wood volume of A. schaffneri using remote sensing, and to complement that information with the results obtained from an estimation method based on forest measurements. The results obtained showed that the crown area was the dendrometric variable that can be used in a wood volume prediction model. In the exploratory analysis between dendrometric variables and remote sensing showed low and negative associations were observed in the four stations analyzed. There are conservation problems due to anthropogenic activities, among which stands out the intensive grazing that results in a decrease of the natural regeneration capacity of Acacia schaffneri.

A study of walkability in Surabaya urban park utilizing the space syntax

The urban parks are open spaces that accommodate people to do various activities. One of the most popular activities is walking. Human experience essentially leads pedestrians to have specific spatial dimensions and configurations in a park. Space syntax exists as a tool to explore the characteristics of the spatial configuration and the influence of the visitors on their activities through their perceptions. Space syntax has been widely applied in urban and human movement studies, despite rarely applied within the scope of urban parks. This study aims to address the debate and offers a new technique in applying the space syntax method. This research employed quantitative methods in interpreting the concept of Walkability and evaluated the design of urban parks by spatial exploration. The result determined the scope of research within the park, the configurational relationships between spaces as well as the visual connection and continuity of the human line of sight. This principle was developed and illustrated based on the three urban parks in Surabaya.

Enhancement of hippocampal-thalamocortical temporal coordination during slow-frequency long-duration anterior thalamic spindles

Temporal nesting of cortical slow oscillations (SO), thalamic spindles and hippocampal ripples indicates the succession of regional neuronal interactions required for memory consolidation. However how the thalamic activity during spindles organizes hippocampal dynamics remains largely undetermined. We analyzed simultaneous recordings of anterodorsal thalamus and CA1 in mice to determine the contribution of thalamic spindles in cross-regional synchronization. Our results indicated that temporal hippocampo-thalamocortical coupling were more enhanced during slower and longer thalamic spindles. Additionally, spindles occurring closer to SO trough were more strongly coupled to ripples. We found that the temporal association between CA1 spiking/ripples and thalamic spindles was stronger following spatial exploration compared to baseline sleep. We further developed a hippocampal-thalamocortical model to explain the mechanism underlying the duration and frequency-dependent coupling of thalamic spindles to hippocampal activity. Our findings shed light on our understanding of the functional role of thalamic activity during spindles on multi-regional information transfer.

Cortical Visual Impairment in Childhood: ‘Blindsight’ and the Sprague Effect Revisited

The paper discusses and provides support for diverse processes of brain plasticity in visual function after damage in infancy and childhood in comparison with injury that occurs in the adult brain. We provide support and description of neuroplastic mechanisms in childhood that do not seemingly exist in the same way in the adult brain. Examples include the ability to foster the development of thalamocortical connectivities that can circumvent the lesion and reach their cortical destination in the occipital cortex as the developing brain is more efficient in building new connections. Supporting this claim is the fact that in those with central visual field defects we can note that the extrastriatal visual connectivities are greater when a lesion occurs earlier in life as opposed to in the neurologically mature adult. The result is a significantly more optimized system of visual and spatial exploration within the ‘blind’ field of view. The discussion is provided within the context of “blindsight” and the “Sprague Effect”.

Using Computational Analysis of Behavior To Discover Developmental Change In Memory-Guided Attention Mechanisms In Childhood

We tested 4-9.5-year-old children on a naturalistic memory-guided attention visual search task. We measured fixation distribution during a search using wearable eye tracking, and simultaneously recorded depth video data for each participant and used computer vision algorithms to track them during navigation. We manipulated object placement and trial order such that nearby objects would be encountered during initial search for reference objects. We used a computational model of top-down guidance for reference object visual features and examined the use of this top-down attention for reference objects during subsequent nearby object search. The data suggest that the value of physical navigation during initial spatial exploration for subsequent memory-guided attention, specifically in early childhood, is in its association with stronger visual representations of goal reference objects during spatial exploration. By middle childhood, visual search times were not impacted by memory engagement.

Online Service with Delay

In this article, we introduce the online service with delay problem. In this problem, there are n points in a metric space that issue service requests over time, and there is a server that serves these requests. The goal is to minimize the sum of distance traveled by the server and the total delay (or a penalty function thereof) in serving the requests. This problem models the fundamental tradeoff between batching requests to improve locality and reducing delay to improve response time, which has many applications in operations management, operating systems, logistics, supply chain management, and scheduling. Our main result is to show a poly-logarithmic competitive ratio for the online service with delay problem. This result is obtained by an algorithm that we call the preemptive service algorithm . The salient feature of this algorithm is a process called preemptive service, which uses a novel combination of (recursive) time forwarding and spatial exploration on a metric space. We also generalize our results to k > 1 servers and obtain stronger results for special metrics such as uniform and star metrics that correspond to (weighted) paging problems.