Dimensions Of Corridors Research Articles

A cadaveric study showing the OLIF corridor dimensions after retraction of the abdominal great arteries and psoas major.

The aim of this study is to assess the oblique lateral interbody fusion (OLIF) corridor dimensions when the abdominal great arteries (the abdominal aorta or common iliac arteries) and psoas major are retracted. Twenty embalmed cadaveric specimens were dissected. The widths of the OLIF operative corridor at L1-2, L2-3, L3-4, and L4-5 were measured with the psoas major and abdominal great arteries in static state, with psoas retraction, and with mild retraction of the abdominal great arteries. The retractable distances of the psoas major and the abdominal great arteries at each lumbar segment were compared. In the static state, the operative corridor gradually narrowed from L1-2 to L4-5, but there was no significant difference in its width between segments (p > 0.05). There was no significant difference in the corridor width between segments after retraction of the psoas major or the abdominal great arteries (p > 0.05). However, retraction of either the psoas major or the abdominal great arteries made the corridor at the L1-5 segments significantly wider than those in the static state (p < 0.05), particularly at L4-5, and the retractable distance of the psoas major was significantly greater (p < 0.05). The cadaveric model demonstrated the use of abdominal great arteries retraction in principle. The OLIF operative corridor could be widened to some extent by retracting the abdominal great arteries, and widened further by retracting the psoas major.

Estimating ungulate migration corridors from sparse movement data

AbstractMany ungulates migrate between distinct summer and winter ranges, and identifying, mapping, and conserving these migration corridors have become a focus of local, regional, and global conservation efforts. Brownian bridge movement models (BBMMs) are commonly used to empirically identify these seasonal migration corridors; however, they require location data sampled at relatively frequent intervals to obtain a robust estimate of an animal's movement path. Fitting BBMMs to sparse location data violates the assumption of conditional random movement between successive locations, overestimating the area (and width) of a migration corridor when creating individual and population‐level occurrence distributions and precluding the use of low‐frequency, or sparse, data in mapping migration corridors. In an effort to expand the utility of BBMMs to include sparse GPS data, we propose an alternative approach to model migration corridors from sparse GPS data. We demonstrate this method using GPS data collected every 2 h from four mule deer (Odocoileus hemionus) and four elk (Cervus canadensis) herds within Wyoming and Idaho. First, we used BBMMs to estimate a baseline corridor for the 2‐h data. We then subsampled the 2‐h data to one location every 12 h (a proxy for sparse data) and fitted BBMMs to the 12‐h data using a fixed motion variance (FMV) value, instead of estimating the Brownian motion variance empirically. A range of FMV values was tested to identify the value that best approximated the baseline migration corridor. FMV values within a species‐specific range (mule deer: 400–1200 m2; elk: 600–1600 m2) successfully delineated migration corridors similar to the 2‐h baseline corridors; overall, lower values delineated narrower corridors and higher values delineated wider corridors. Optimal FMV values of 800 m2 (mule deer) and 1000 m2 (elk) decreased the inflation of the 12‐h corridors relative to the 2‐h corridors from traditional BBMMs. This FMV approach thus enables using sparse movement data to approximate realistic migration corridor dimensions, providing an important alternative when movement data are collected infrequently. This approach greatly expands the number of datasets that can be used for migration corridor mapping—a useful tool for management and conservation across the globe.

Morphometric analysis of sacral corridor in the upper three sacral segments to prevent neurovascular injury.

Although studies of the sacral corridor dimension have been reported in the European population, little attention has been paid to this issue in the Asian population. The purpose of the study is to estimate the safe dimension of the corridor to avoid neurovascular damage during the fixation of the sacral fracture. The study aimed to examine the cephalocaudal (vertical) and the anteroposterior diameter of the bony passage in the upper three sacral segments. The study further examines the effect of age and sex on corridor dimensions at different sacral levels. Three-dimensionally reconstructed sacra from computed tomography of normal subjects were included in the study. Cephalocaudal and anteroposterior diameters were measured in coronal and axial sections using Geomagic Freeform Plus software. Anteroposterior diameter of the sacral corridor at the first, second, and third sacral segments are significantly higher in males (P=0.013, 0.0011, and <0.0001, respectively). The length of the sacrum also revealed sexual dimorphism (P<0.00016). The anteroposterior diameter of the second sacral segment (ap-S2c) correlated moderately with the first sacral anteroposterior diameter (ap-S1c) (R=0.519, P<0.001). The ap-S2c exhibited a moderate correlation to the third sacral segment (ap-S3c) (R=0.677, P<0.001). The sacral corridor at the level of S1 has the largest cephalocaudal (18.25 mm) and anteroposterior diameter (17.11 mm). Placement of the screw in the first sacral corridor may avoid damage to the neurovascular bundle during the fixation of the sacral fracture.

Assessment of Residential Satisfaction using Gap Analysis: A Case Study in Naypyitaw City, Myanmar

This research paper conducts an evaluation of residential satisfaction within government-provided four-storied apartment complexes situated in civil-servant housing areas in Naypyitaw City, Myanmar. As the construction of these apartment buildings continues to address the housing demands of civil servants, comprehending the determinants of residents' contentment becomes paramount. The study encompasses data collected from 500 households through structured questionnaires employing a multi-cluster sampling approach. These questionnaires utilize a five-point Likert Scale format to gauge residents' levels of importance and satisfaction. Gap Analysis is employed to scrutinize the gathered data, ultimately identifying seven pivotal attributes that hold the potential to substantially enhance residential satisfaction. These attributes encompass ceiling height, apartment layout plan, room and corridor dimensions, quantity of rooms, staircase design, neighborhood relations, and proximity to police stations. Based on these revelations, recommendations are tendered, advocating the modification and reevaluation of these attributes in forthcoming housing developments. This underscores the imperative need for creating a livable city by ensuring the provision of essential services in closed proximity to residential areas.

Layout considerations on compound survival shelters for blast mitigation: A finite-element approach

The safety of both military personnel and equipment in unstable regions has for a long time been a major issue and concern. Protective shelters with multiple configurations have been widely used to meet safety requirements. Since military compounds are subjected to different types of threats, such as the detonation of improvised explosive devices (IED), a good understanding of the response of such shielding structures to blast waves is critical. A three-dimensional finite element (FE) model of a corner-entry ISO 20 ft container HESCO-Bastion survival shelter is developed, validated and tested under the external detonation of explosive charges. The FE model is validated against experimental data and used to investigate the protective performance of the shelter by considering several design-related parameters, such as charge location, roof extension, interior corridor dimensions and the effect of venting and its location. Results are discussed in terms of peak overpressure and maximum impulse at discrete locations around the container, and it is found that the shelter is the least efficient in mitigating the blast load propagation when the explosive material is at an angle of 45° to the entrance. Also, while the protective roof at the entrance plays a significant role in protecting the container from air-borne threats, it is observed that it contributes to higher pressure and impulse data within the shelter, for detonations at ground level, with impulse amplifications as high as 94% when fully covering the entrance area. Contrarily, varying the distance between the container and the HESCO-Bastions is found to have minimal impact on the impulse, while naturally decreasing the peak pressure for increasing distances. Venting (through openings) can lead to up to 95% reduction in the peak pressure, whilst not affecting the impulse.

Boom-corridor thinning removal portion estimation with agent-based simulation

Young forest stand thinning is sometimes neglected by forest owners due to its high costs. To increase the harvester productivity and lower thinning costs of young forest stand, a new thinning method, Boom-corridor thinning, has been developed. A simulation model was developed to investigate the removal portion of this new method and discuss the dimensions of corridors. In order to have real-life forest stand information for the simulation model, remote sensing methods were used to construct 27 test plots from three forest stands located in Pieksämäki, Finland. The simulation model was run with various corridor geometries and the results revealed that areas where trees are removed, called corridors, and areas between corridors should have 0.5 to 1.0 width ratio to achieve a removal portion of approximately 50%. From a harvester productivity standpoint, the corridors should be as wide as possible, but from a forest versatility and management point of view, the corridors should be narrow. This is the reason why corridors are usually from 1 to 3 meters wide. Vast result sets of the simulation model show how Boom-corridor thinning geometry affects removal portions and allows the planning of the thinning to take into account the removal portion of the trees and forest management perspective. In practice the simulation is not very useful for determining the Boom-corridor geometry and it is more practical to have the operator choose or use an area-based equation to decide the geometry.

Dental arch and Smile Changes Following Miniscrew Anchored En-masse Retraction of Anterior Teeth in Class II Division 1 Malocclusion

Objective: to evaluate dental arch and smile changes after miniscrew anchored en-masse retraction of maxillary anterior teeth in Class II division 1 malocclusion cases. Methods: A total of 22 adult patients (mean age, 19.78 + 1.24 years) with Class II division 1 malocclusion were randomly assigned to 2 groups; group I (11 patients treated with miniscrew anchored en-masse retraction) and group II (11 patients treated with two-step retraction using conventional anchorage). Skeletal, dentoalveolar and smile changes were analyzed in both groups using standardized photographs, study casts, and lateral cephalograms before and after space closure. Results: Miniscrew anchored en-masse retraction showed a statistically significant decrease in upper incisor display (U1UL) (-2.22±1.33; P 0.05). Group II demonstrated a statistically significant decrease in IMW (-1.63 ± 1.19, P<0.05) and significant mesialization of maxillary first molars (U6-MR, U6-LR) (-2.46 +1.64, -1.03 + 1.13, P˂0.05). Conclusion: The use of miniscrews as a means of anchorage during retraction of maxillary anterior teeth provides an absolute anchorage for maxillary first molars with in either anteroposterior or vertical direction. Therefore, it could effectively reduce upper incisors display without altering buccal corridor dimensions or affecting the smile arc.

Computed tomography evaluation of proposed implant corridors in canine thoracic vertebrae.

Identify acceptable implant corridors in the normal canine thoracic vertebrae (T) from T1 to T9. Retrospective study. Computed tomographic (CT) studies of normal canine thoracic spines (n=39). CT imaging studies of normal T1-T9 canine spines were evaluated by five independent observers. Each identified a proposed corridor, measured the width, length, and angle off mid-sagittal that the corridor occupied. CT studies were from 39 dogs weighing 3.19-60 kg (mean 10.72, SD 9.9 kg). Vertebral corridors ranged in average width from 3.8 to 5.2 mm, the widest being located at T1. They ranged in average length from 13.3 to 17.5 mm, shortest being T1 and longest being T6. The angle of corridors varied the most between individual vertebrae at T1-T3. The average corridor angles were: T1=38°, T2=32°, T3=27°, T4=26°. T5-T9 angle ranged from 23° to 24°. The average dimensions of corridors measured in dogs weighing 3.1-60 kg were consistent with those of commercially available cortical screws and pins. Corridor trajectories identified in this population can be achieved from a dorsal approach between T5 and T9. A dorsal approach for implant placement would be challenging for T1-T4 due to the variability found in these vertebrae as well as regional anatomical constraints.

Is the Iliac Cortical Density Similarly Positioned in the Developing Pediatric Pelvis?

The iliac cortical density (ICD) is a critical fluoroscopic landmark for pelvic percutaneous screw placement. Our purpose was to evaluate the ICD as a landmark in pediatrics and quantify the diameter of osseous pathways for 3 screw trajectories: iliosacral (IS) at S1 and transiliac-transsacral (TSTI) at S1 and S2. Two hundred sixty-seven consecutive pelvic CT scans in children 0-16 years of age were analyzed. ICD and S1 vertebral heights were measured at multiple regions along S1. Their height and corresponding ratios, as well as osseous screw corridor dimensions were compared between age groups and by the dysmorphic status. In the nondysmorphic pelvises, S1 height, ICD height, and the ICD to S1 height ratio increased across age groups for all locations (P < 0.001). All 3 screw pathway diameters increased with age (P < 0.001). In the dysmorphic group, there was no increase in ICD to S1 height ratio with age. Except for the age 0-2 group, the ICD to S1 height ratios were significantly larger in the nondysmorphic group. In the dysmorphic group, S1 TSTI pathway remained narrow with age, whereas IS at S1 and TSTI at S2 had a significant increased diameter with age (P < 0.001). The ICD is a useful fluoroscopic landmark for percutaneous screw placement in the pediatric pelvis. For nondysmorphic pelvises, the ICD to S1 height ratio, as well as osseous corridors for IS, TSTI at S1, and TSTI at S2 screw trajectories increase significantly with age. The margin for safe screw placement in S1 is smaller for younger and dysmorphic pelvises.

Effective corridor width: linking the spatial ecology of wildlife with land use policy

Wildlife corridors are a policy tool to maintain or restore connectivity through human-modified landscapes. While corridors have been an important concept in wildlife conservation for decades, there is little evidence to guide their design. Specifically, width is one of the most contentious dimensions of corridors because it often limits industrial, residential, or recreational expansion. Building on concepts that describe how wildlife avoid infrastructure or people—zone of influence and the flight initiation distance—we present a conceptual approach to design and assess the management effectiveness of wildlife corridors through a concept we define as effective corridor width. The effective corridor width is the minimum spatial dimension needed to abate human influence on animal movement through the corridor. We searched for case studies documenting the zone of influence and the flight initiation distance from recreational trails and residential development for four species of carnivore: black bears, grizzly (brown) bears, gray wolves, and cougars. From these studies, we synthesized information on the effective corridor width, which varied from 3000 to 6000 m for residential areas and 400 to 1000 m for trails, depending on the species. We examined the effective corridor width in a case study from Alberta, Canada, where debate over the appropriate width of designated wildlife corridors has been ongoing for decades. Our analysis is a step towards developing robust, empirically derived guidelines for designing and managing wildlife corridors.

Gender-Associated Differences in Sacral Morphology Do Not Affect Feasibility Rates of Transsacral Screw Insertion. Radioanatomic Investigation Based on Pelvic Cross-sectional Imaging of 200 Individuals.

Retrospective radioanatomic single-center cohort study. To investigate sex-specific differences in transsacral corridor dimensions, determine feasibility rates of transsacral screw placement without extended safety zones around planned screw positions, and develop an index defining sacral dysmorphism (SD) irrespective of transsacral corridor diameters. Previously reported SD definitions used radiologically identifiable pelvic characteristics or predefined minimum diameter thresholds of transsacral corridors in the upper sacral segment including safety zones for screw placement. Technical progress of surgical 3D image guidance improved sacral screw insertion accuracy questioning established minimum diameter threshold-based SD definitions. Datasets from cross-sectional pelvic imaging of 100 women and 100 men presenting to a general hospital from July 2018 through August 2018 were included in a database to evaluate transsacral trajectory rates, and dimensions of transsacral corridor lengths, widths (TSCWs), and heights (TSCHs) in sacral segments I to III (S1-3). SD was assumed, if no transsacral trajectory was found in S1 with a corridor diameter of at least 7.5 mm. Women presented significantly higher rates of transsacral trajectories in the inferior sector of S1 (P = 0.03), and larger transsacral corridor lengths in S2 (superior sector, P = 0.045), and S3 (central position, P = 0.02). In men, significantly higher feasibility rates were found for the placement of two transsacral screws in S2 (P = 0.0002), and singular screws in S3 (P = 0.006), with larger S1- (P = 0.0002), and central S2-TSCWs (P = 0.006). SD was prevalent in 17% of women, and 16% of men (P = 0.85). Calculating TSCW ratios of S1 and S2 was significantly indicative for SD at values below a threshold of 0.8 in women (P < 0.00001), and men (P = 0.0004). SD is independent of sex despite significant differences in sacral morphology. An index defining SD irrespective of absolute transsacral corridor dimensions is presented to reliably differentiate dysmorphic from nondysmorphic sacra in women and men. 2.

A re-examination of the role of friction in the original Social Force Model

The fundamental diagram of pedestrian dynamics gives the relation between the density and the flow within a specific enclosure. It is characterized by two distinctive behaviors: the free-flow regime (for low densities) and the congested regime (for high densities). In the former, the flow is an increasing function of the density, while in the latter, the flow remains on hold or decreases. In this work, we perform numerical simulations of the pilgrimage at the entrance of the Jamaraat bridge (pedestrians walking along a straight corridor) and compare flow-density measurements with empirical measurements made by Helbing et al. (2007). We show that under high density conditions, the basic Social Force Model (SFM) does not completely handle the fundamental diagram reported in empirical measurements. We use analytical techniques and numerical simulations to prove that with an appropriate modification of the friction coefficient (but sustaining the SFM) it is possible to attain behaviors which are in qualitative agreement with the empirical data. Other authors have already proposed a modification of the relaxation time in order to address this problem. In this work, we unveil the fact that our approach is analogous to theirs since both affect the same term of the reduced-in-units equation of motion. We show how the friction modification affects the pedestrian clustering structures throughout the transition from the free-flow regime to the congested regime. We also show that the speed profile, normalized by width and maximum velocity yields a universal behavior regardless of the corridor dimensions.

Optimising the inter‐distance between transmitters in a multi‐cell VLC system

In this study, the authors find the optimum inter-distance between visible light access points (VAPs) in a multi-cell system. This is an important issue to avoid the lack of resources resulting from wiring too few VAPs while minimising the installation cost. This study uses a one-dimensional corridor model suitable for many practical environments such as train aisles and hospital/library corridors. They provide formulas for the average rate achieved per user to determine the optimal inter-VAP distance. These formulas depend on information that is usually available in the design step such as the corridor dimensions, luminaries' parameters, and user density. They consider different power allocation techniques and different frequency reuse factors. The analysis shows that the optimum inter-VAP distance depends mainly on the corridor dimensions and not as much on the communication technique. Higher frequency reuse factors reduce the interference and improve the performance in the case of small cells. Specifically, the results determine the corridor dimensions that are better served by multi-VAP rather than a single centred VAP. Many important design issues are answered throughout this study such as how the ceiling height and the estimated crowdedness in the corridor affect the optimum cell size.

Analysis of the far-medial transoral endoscopic approach to the infratemporal fossa.

To demonstrate anatomic relationships of the far-medial transoral endoscopic assisted approach (FMT-EAA) to the infratemporal fossa (ITF) and define the corridor dimensions, surgical freedom, and limitations associated with this approach. Cadaveric study. Twenty ITFs (10 specimens) were dissected with the assistance of 0 °, 30 °, and 45 ° rod-lens endoscopes. Image guidance was used to confirm and measure the corridors' structural boundaries and document the anatomical relationships encountered in this approach. Access to the ITF via the FMT-EAA can be divided into two secondary surgical corridors: the superomedial and inferolateral triangles, each of which provides access to different areas. The superomedial triangle is bounded medially by the lateral pterygoid plate and posterolateral maxillary sinus wall, superiorly by the greater sphenoid wing, and inferolaterally by the lateral pterygoid muscle. The inferolateral triangle is bounded superiorly by the lower head of the lateral pterygoid muscle, inferiorly by the medial pterygoid muscle, and laterally by the mandible. Using a standard 19-mm endoscope, the FMT-EAA achieves a mean surgical freedom of 231 mm and 161 mm in the vertical and horizontal planes, respectively. FMT-EAA adequately exposes critical structures of the ITF. This technique is a viable option for the management of selected ITF lesions, either alone or in combination with alternative minimally invasive approaches to the region. NA Laryngoscope, 128:2273-2281, 2018.

Critical dimensions of trans-sacral corridors assessed by 3D CT models: Relevance for implant positioning in fractures of the sacrum.

Trans-sacral implants can be used alternatively to sacro-iliac screws in the treatment of osteoporosis-associated fragility fractures of the pelvis and the sacrum. We investigated trans-sacral corridor dimensions, the number of individuals amenable to trans-sacral fixation, as well as the osseous boundaries and shape of the S1 corridor. 3D models were reconstructed from pelvic CT scans from 92 Europeans and 64 Japanese. A corridor of <12 mm was considered critical for trans-sacral implant positioning, and <8 mm as impossible. A statistical model of trans-sacral corridor S1 was computed. The limiting cranio-caudal diameter was 11.6 mm (±5.4) for S1 and 14 mm (±2.4) for S2. Trans-sacral implant positioning was critical in 52% of cases for S1, and in 21% for S2. The S1 corridor was impossible in 26%, with no impossible corridor in S2. Antero-superiorly, the S1 corridor was limited not only by the sacrum but in 40% by the iliac fossa. The statistical model demonstrated a consistent oval shape of the trans-section of corridor S1. Considering the variable in size and shape of trans-sacral corridors in S1, a thorough anatomical knowledge and preoperative planning are mandatory using trans-sacral implants. In critical cases, S2 is a veritable alternative. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2577-2584, 2017.

Computational Anatomy of C2 Based on Quantitative Computed Tomography and its Implications for Screw Positioning

Introduction Surgical fixation of the axis (C2) includes screw positioning through bony corridors close to vital structures. However, human bones exhibit large variations in size and shape across individuals and populations. A 3D statistical model of C2 using Quantitative Computed Tomography (QCT) was created to analyze the anatomical variations and to understand their implications for screw positioning. Material and Methods 106 standard clinical QCTs from 46 adult female and 60 male European patients, aged 52.0 years ± 19.9 years, with intact C2s have been included in this study. The mean image resolution was 0.5mm × 0.5mm in the axial plane and 0.6mm in craniocaudally direction. After anonymization 3D statistical modeling of C2 was performed. This included the computation of averaged 3D surface and volumetric bone mineral density (vBMD) models and principal component analysis (PCA). Transpedicular and odontoid screw templates were virtually implanted and their corridors were analyzed. Results PCA revealed a highly variable anatomy of C2 in which size was the predominant variation in the 1st principal component (PC), whereas shape changes were primarily described by the remaining PCs. The largest shape variation was observed at the spinous and transverse processes and the transverse foramina. Comparison of the averaged 3D surface models of C2 for men and women separately revealed mainly a difference in size: The model for males was ~7% larger in the axial plane (anterior-posterior and left-right directions) and ~9% in craniocaudal direction. 3.5mm odontoid screw templates could be virtually implanted in all C2. The average corridor length was 39.2mm ± 2.8mm and the median screw length 38mm. The average corridor length difference between the genders was ~8%. The corridor exhibited the lowest average vBMD value (199.0 mgCaHA/ml) underneath the basis of the odontoid process and a maximum value (911.2 mgCaHA/ml) at its upper part near the cortical shell. Virtual implantation of a 3.5mm C2 pedicle screw with 1mm safety zone was not possible in 31.1% due to interference with the vertebral artery. In 26.4% a 3.5mm screw and in 42.5% a 4.5mm screw could be positioned. The median screw length was 32mm. The average pedicle corridor length was 28.7mm ± 1.9mm with an average convergence of 21.0° ± 3.6° to the sagittal plane and an average ascent of 18.7° ± 3.5° in cranial direction. The lowest average vBMD value for the corridor was located in the trabecular bone of the vertebral body (314.8 mgCaHA/ml) whereas the maximum value (689.2 mgCaHA/ml) was measured near the anterior cortical shell of the vertebral body. The average entry point was ~5mm lateral from the medial border of the inferior articular process and ~10mm cranial from its caudal border. Conclusion We established a 3D statistical model of C2 using QCTs. It revealed largely variable surfaces, bone quality and corridor dimensions and allowed the efficient 3D assessment of parameters relevant for screw positioning. There are anatomical conditions that allowed/not allowed for screw positioning. Surgical decision making must rely on both, a thorough anatomical understanding and the given individual situation. Acknowledgments This work was supported by AOSpine TK of the TK System of the AO Foundation, Davos, Switzerland. D. Gehweiler received a research fellowship grant from the AO Research Institute Davos, Davos, Switzerland.

The Anterior Subcallosal Approach to Third Ventricular and Suprasellar Lesions: Anatomical Description and Technical Note

Surgical access to the third ventricle is challenging, given the depth of the operative field and close proximity of vital neural structures that must be traversed. For anterior third ventricular lesions, approach options include anterior transcallosal or transcortical, subfrontal, frontotemporal, or endonasal. The subcallosal approach, a translamina terminalis approach, is unique in that the surgical corridor is just below the corpus callosum, minimizes retraction and preserves corpus callosum integrity. Case examples are provided, and an anatomical study delineating the dimensions of the surgical corridor is performed. Two latex-injected cadaver heads were used to describe the subcallosal corridor. A magnetic resonance imaging scan was obtained and registered with neuronavigation for correlative anatomical illustration. Depth, dimensions, and cross-sectional area were measured for the subcommunicating and supracommunicating corridors. The surgical depth for anterior transcallosal, subcallosal, and subfrontal approaches was 7.5 cm, 7.7 cm, and 7.6 cm respectively. The average corridor dimensions for the subcallosal approach were 14.75 × 6.63 mm compared with 8.88 × 5.38 mm for the subcommunicating corridor. Cross-sectional area of the subcommunicating corridor was 30.62 mm(2) compared with 80.42 mm(2) for supracommunicating. This was easily enlarged to 156.62 mm(2) with gentle retraction. The anterior subcallosal approach is a safe approach for lesions of the third ventricle that avoids splitting the corpus callosum and resecting unnecessary brain and minimizes brain retraction. This corridor is superior to the traditional subfrontal approach in terms of working space and compares favorably to the anterior transcallosal approach without disrupting the corpus callosum.

Delimitación espacial del corredor económico Ensenada-Mexicali

En este artículo se proponen elementos y parámetros cuantitativos y cualitativos para delimitar el corredor económico Ensenada-Mexicali. Además de incluir los efectos relativos a su doble condición de frontera y península y de definir su composición y estructura, se establecen su dimensión y áreas de influencia a partir de un análisis de proximidad, para así obtener una delimitación que va más allá de la región políticoadministrativa, concepción artificial que conlleva problemas para el análisis y la representación. Esta cuestión se supera mediante una alternativa metodológica que favorece el análisis integral desde una perspectiva relacional y organizativa en la que la unidad geográfica definida es útil para impulsar la competitividadregional.

A fast flow control algorithm for real-time emergency evacuation in large indoor areas

Evacuation in an emergency is always an important issue for shopping malls, subway stations and other populous indoor places. The purpose of evacuation is to evacuate people from the danger zone through exits within the shortest possible time. To help evacuation missions to be carried out efficiently and effectively by rescuers, a fast evacuation approach is needed. The proposed fast flow control algorithm in this paper calculates evacuation paths in accordance with the floor plan (which contains detailed locations and dimensions of corridors and exit doors) and the total number of evacuees. The calculation is based on minimum overall evacuation time and an optimal number of evacuees assigned to each evacuation path. An example is presented at the end of the paper to illustrate real-time implementation of the proposed fast flow control algorithm.