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Santiago, the capital city of Chile, has seven million inhabitants in an area of 850 km2. This city has a metro network with seven lines extending 140 kilometers and transports approximately 2.6 million people daily. The bus system has undergone significant transformations over the last three decades. The most relevant change having been Transantiago, the public transportation system implemented in 2007 for Santiago, Child, which combines the use of Metro and buses (BRT). Metropolitan Mobility Network (called Red) is the latest version of the public transportation plan. This paper aims to analyze the current subway infrastructure using the continuous approximation method for Santiago, Chile. We previously proposed a macroscopic methodology to identify the needs for an adequate level of service in urban mobility and transportation, and we applied it to Santiago’s Metro network. Our work focuses on functionality and demand distribution. Santiago’s demand varies spatially in volume and extension throughout the city. Using the latest origin-destination survey from 2012, we deduct the critical components in this current network structure. It is worth mentioning that the Metro design bases its network on a ring-radial structure. With our macroscopic model applied to Santiago, Chile, we have detected infrastructure needs in the current transit network. The supply of infrastructure should increase for two reasons: first, to achieve balanced cost levels between users and the agency and second, to reduce subway occupations. The optimal model outcomes for Santiago define the optimal network in which the system requires five rings and ten end-to-end longitudinal lines (20 radial routes), including lower levels of occupation. The obtained results are a good preliminary solution, considering the subway infrastructure supply could be sub-estimated in the public transportation plan. The authors had support from the Barcelona Innovative Transportation (BIT) Research Group. Moreover, the first author's work was supported by Chile's National Agency for Research and Development (ANID) / Becas-Chile Doctoral Scholarship Program No. 72160291. The first author had support from the Project 092112MT of the DICYT of the University of Santiago of Chile (USACH).

Resumen Caso clinico Presentamos el caso de un varon de 45 anos con excavacion coroidea asociada a una membrana neovascular coroidea no incluida en el area de la excavacion. Se describen las caracteristicas clinicas mediante retinografia, angiografia fluoresceinica, tomografia de coherencia optica y angiotomografia. El paciente fue tratado con 3 inyecciones de bevacizumab, consiguiendose la inactivacion de la membrana. Discusion La excavacion focal coroidea puede aparecer asociada a una membrana neovascular situada por fuera de los limites de la excavacion. El estudio mediante diversas modalidades de imagen nos permite una completa descripcion de sus caracteristicas, antes y despues del tratamiento.

Case report The case is presented of 42 year-old woman with no significant medical history, with severe headaches, nausea and vomiting, hearing loss, and alteration of mental status with disorientation and confusion. Ophthalmic examination showed optic disc hyperaemia in right eye, and focal areas of arteriolar occlusion in both eyes. Audiometry demonstrated bilateral neurosensory hypoacusis. Magnetic Resonance Imaging showed multiple small round hyperintense lesions located in the splenium, corpus callosum, basal ganglia, and white matter. Discussion Besides branch retinal arteriolar occlusion, the angiopathy in Susac's syndrome may affect the optic disc vessels.

Resumen Caso clinico Mujer de 42 anos, sin antecedentes de interes que acude con cefalea severa, nauseas, vomitos, perdida de la audicion y alteraciones mentales con desorientacion y confusion. El examen oftalmologico revelo la presencia de hiperemia del disco optico derecho y de areas focales de oclusion arteriolar en ambos ojos. La audiometria puso de manifiesto una hipoacusia bilateral neurosensorial. En la resonancia magnetica cerebral se detectaron multiples lesiones de pequeno tamano hiperintensas localizadas en el esplenio, cuerpo calloso, ganglios basales y sustancia blanca. Discusion Ademas de la oclusion de las arteriolas retinianas, la angiopatia del sindrome de Susac puede afectar a los vasos del disco optico.

Case report The case is presented of a 45 year-old man with a focal choroidal excavation associated with choroidal neovascularisation not included in the area of excavation. Clinical features were analyzed using retinography, fluorescein angiography, optical coherence tomography, and optical coherence tomography angiography. The patient was treated with 3 intravitreal injections of bevacizumab, with a good response. Discussion Focal choroidal excavation can be associated with choroidal neovascularization not included in the area of excavation. Multimodal imaging provides a complete description of clinical features, before and after treatment.

Case report The case is presented of a 42-year-old man with episodes of unilateral uveitis in his right eye. Ophthalmic examination showed a granulomatous anterior uveitis with vitritis. Systemic investigations revealed non-nephrotic proteinuria and microhaematuria. A renal biopsy showed IgA nephropathy. Discussion Uveitis and glomerulonephritis may have common immunological pathogenesis. IgA nephropathy should be a differential diagnosis in patients with uveitis and nephropathy.

Resumen Caso clinico Presentamos el caso de un varon de 42 anos de edad con varios episodios de uveitis unilateral en su ojo derecho. El examen oftalmologico mostro una uveitis anterior granulomatosa con vitritis. El estudio sistemico puso de manifiesto una proteinuria de rango no nefrotico y microhematuria. La biopsia renal revelo una nefropatia IgA. Discusion Las uveitis y las glomerulonefritis podrian tener mecanismos inmunologicos comunes. En el diagnostico diferencial de los pacientes con uveitis y nefropatias deberia incluirse la nefropatia IgA.

Resumen Caso clinico Presentamos el caso de una mujer de 54 anos con una coriorretinopatia serosa central diagnosticada erroneamente de enfermedad de Vogt-Koyanagi-Harada y tratada con corticoides sistemicos. La paciente desarrollo un desprendimiento de retina exudativo bulloso en ambos ojos. Discusion La interrupcion del tratamiento con corticoides junto con el drenaje quirurgico del liquido subretiniano y la aplicacion de terapia fotodinamica consiguio la mejoria anatomica y funcional. El correcto diagnostico de las formas atipicas de la enfermedad podria evitar las complicaciones del uso inadecuado de los corticoides.

Case report A 36 year-old male with a recent HIV diagnosis, presented with loss of vision of his left eye. Ophthalmoscopy revealed a unilateral yellowish placoid lesion in the macula. After fluorescein angiography, optical coherence tomography, optical coherence tomography angiography, syphilis serology, and cerebrospinal fluid results, he was diagnosed with neurosyphilis and syphilitic posterior placoid chorioretinitis. Discussion Acute syphilitic posterior placoid chorioretinitis is a rare ocular manifestation of syphilis. All patients with characteristic clinical and angiographic findings of acute syphilitic posterior placoid chorioretinitis should be tested for a neurosyphilis and human immunodeficiency virus co-infection. Early treatment with intravenous penicillin is usually effective with good visual results.

Case report The case is presented on a 54-year-old woman with a central serous chorioretinopathy, misdiagnosed as Vogt–Koyanagi–Harada disease, and treated with systemic corticosteroids. The patient presented with a bilateral bullous exudative retinal detachment. Discussion Discontinuation of corticosteroid therapy, surgical drainage of subretinal fluid, and photodynamic therapy, led to anatomical and functional improvement. The recognition of an atypical presentation of central serous chorioretinopathy may avoid complications of the inappropriate treatment with corticosteroids.

Clinical case The case is presented of a 16 year-old girl with unilateral congenital retinal macrovessel associated with peripheral telangiectasia and retinal ischaemia. Discussion Congenital retinal macrovessel is a rare finding. To the best of our knowledge this is the first report of this unusual presentation of congenital retinal macrovessel. After 21 months of follow up, visual acuity remained stable, and no complications developed.

Resumen Caso clinico Presentamos el caso de una paciente de 16 anos con un macrovaso retiniano congenito unilateral, con telangiectasias retinianas perifericas asociadas a zonas de isquemia. Discusion Los macrovasos retinianos congenitos constituyen un hallazgo raro, no habiendose descrito casos asociados a telangiectasias retinianas e isquemia periferica. Tras 21 meses de seguimiento, la paciente se mantiene estable, conservando la vision inicial y sin complicaciones adicionales.

Case report The case is presented of a 39 year-old man with a combined hamartoma of the retina and retinal pigment epithelium, who experienced progressive visual loss and worsening of metamorphopsia. The patient underwent vitrectomy and epiretinal component peeling, with improvement in visual acuity, metamorphopsia, and retinal architecture, assessed by optical coherence tomography. Discussion Selected patients with combined hamartomas of the retina and retinal pigment epithelium may benefit from surgical management.

Resumen Caso clinico Presentamos el caso de un paciente varon de 39 anos, con un hamartoma combinado de retina y epitelio pigmentario de retina. El paciente referia disminucion progresiva de la vision y empeoramiento de la metamorfopsia. Se realizo una vitrectomia con pelado de la membrana epirretiniana, consiguiendo una mejoria de la agudeza visual y de la metamorfopsia, asi como de la arquitectura retiniana en la tomografia de coherencia optica. Discusion Algunos pacientes seleccionados con hamartomas combinados de retina y epitelio pigmentario podrian beneficiarse de la realizacion de una vitrectomia.

Case report We present the case of a 55-year-old man with a non-small cell lung adenocarcinoma, who presented with choroidal metastasis. The patient showed a decrease in visual acuity. His evaluation revealed unilateral choroidal metastasis secondary to carcinoma of the lung. The patient received afatinib with complete regression of choroidal metastasis after one year follow-up. Discussion Choroidal metastasis may be the initial sign of lung cancer. This case highlights the importance of a thorough systemic evaluation in patients with choroidal tumors. Afatinib was effective against choroidal metastasis of a lung adenocarcinoma with EFGR mutation.

Case report We present the case of a 69-year-old woman with unilateral retinal vasculitis. Investigations showed asthma, rhinosinusitis, nasal polyposis, peripheral blood eosinophilia, increased sedimentation rate, proteinuria, and antiphospholipid antibodies. Anti-neutrophil cytoplasmic antibodies (ANCA) were negative. Discussion Although her anti-neutrophil cytoplasmatic antibody (ANCA) status was negative, taking into account the other clinical and laboratory features, retinal vasculitis was thought to be an ocular manifestation of Churg–Strauss syndrome. Treatment was started with high-dose corticosteroids and anticoagulant therapy.

Resumen Caso clinico Presentamos el caso de un varon de 55 anos, con un adenocarcinoma no microcitico de pulmon, que comenzo con una metastasis coroidea. El paciente mostraba disminucion de la agudeza visual. El examen revelo una metastasis coroidea unilateral secundaria al tumor. Tras el tratamiento con afatinib, se consiguio la regresion completa. Discusion Las metastasis coroideas pueden ser la primera manifestacion de un cancer de pulmon. De ahi la importancia de una evaluacion completa en pacientes con tumores coroideos. El afatinib se mostro efectivo en el tratamiento de las metastasis coroideas de un carcinoma de pulmon con mutacion EFGR.

Resumen Caso clinico Presentamos el caso clinico de una mujer de 69 anos, con una vasculitis retiniana unilateral. El estudio del caso mostro la presencia de asma, sinusitis con polipos nasales, eosinofilia en sangre periferica, aumento de la velocidad de sedimentacion, proteinuria y anticuerpos antifosfolipidicos. Los anticuerpos antineutrofilos citoplasmaticos fueron negativos. Discusion A pesar de la ausencia de anticuerpos antineutrofilos citoplasmaticos, se considero el diagnostico de un sindrome de Churg-Strauss, dadas las otras manifestaciones clinicas y de laboratorio, iniciandose un tratamiento con altas dosis de corticoides y anticoagulantes.

Resumen Caso clinico Se presenta el caso clinico de un varon de 63 anos con una atrofia macular en el curso de un sindrome de Terson. El paciente mostraba una disminucion de la agudeza visual con adelgazamiento macular observado en la tomografia optica de coherencia. Discusion El paciente presento una atrofia macular probablemente secundaria a una hemorragia en polo posterior, tras sindrome de Terson causado por la rotura de un aneurisma cerebral.

Case report The case is presented on a 63-year-old patient with Terson's syndrome who complained of loss of visual acuity. The optical coherence tomography showed macular atrophy. Discussion The patient developed macular atrophy probably secondary to macular hemorrhage caused by the rupture of a cerebral aneurysm.

Nectar is a solution of mainly three sugars: sucrose, glucose and fructose. Studies have demonstrated that pollinators have preferences according to the sugar composition presented in their diet, and these preferences may be caused by sugar assimilation capacities. However, sugar flavor could also play an important role for sugar preferences of nectar-feeding animals. We evaluated the sugar gustatory thresholds of the broad-billed hummingbird Cynanthus latirostris for sucrose, glucose, fructose and a 1:1 mixture of glucose–fructose. We presented eight C. latirostris to paired feeders containing either a sugar solution or pure water. Additionally, we conducted sugar preference tests at three different concentrations (146, 730 and 1022 mmol L − 1 ), to relate sugar preferences with sugar gustatory thresholds. C. latirostris had different gustatory thresholds for the three different sugars tested. At low sugar concentrations (146 mmol L − 1 ), sugar selection followed the gustatory thresholds. Hummingbird sugar preference patterns can be affected by different mechanisms, both pre- and post-ingestive. At low concentrations gustatory thresholds may play an important role to determine sugar selection. However, at intermediate and high concentrations, sugar assimilation rates, and velocity of food processing generated by osmotic constraints, can be the mechanisms that explain the sugar selection of these animals.