Un enfoque fisiológico para los procesos oceánicos y los cambios glaciares-interglaciares del CO2 atmosférico

18 pages, 6 figures, 1 table[EN] One possible path for exploring the Earth’s far-from-equilibrium homeostasis is to assume that it results from the organisation of optimal pulsating systems, analogous to that in complex living beings. Under this premise it becomes natural to examine the Earth’s organisation using physiological-like variables. Here we identify some of these main variables for the ocean’s circulatory system: pump rate, stroke volume, carbon and nutrient arterial-venous differences, inorganic nutrients and carbon supply, and metabolic rate. The stroke volume is proportional to the water transported into the thermocline and deep oceans, and the arterial-venous differences occur between recently-upwelled deep waters and very productive high-latitudes waters, with atmospheric CO2 being an indicator of the arterial-venous inorganic carbon difference. The metabolic rate is the internal-energy flux (here expressed as flux of inorganic carbon in the upper ocean) required by the system’s machinery, i.e. community respiration. We propose that the pump rate is set externally by the annual cycle, at one beat per year per hemisphere, and that the autotrophic ocean adjusts its stroke volume and arterial-venous differences to modify the internal-energy demand, triggered by long-period astronomical insolation cycles (external-energy supply). With this perspective we may conceive that the Earth’s interglacial-glacial cycle responds to an internal organisation analogous to that occurring in living beings during an exercise-recovery cycle. We use an idealised double-state metabolic model of the upper ocean (with the inorganic carbon/nutrients supply specified through the overturning rate and the steady-state inorganic carbon/nutrients concentrations) to obtain the temporal evolution of its inorganic carbon concentration, which mimics the glacial-interglacial atmospheric CO2 pattern[ES] Un posible camino para el estudio de la homeóstasis fuera-de-equilibrio de la tierra es suponer que resulta de la organización de sistemas pulsátiles optimizados, análoga a aquélla en seres vivos complejos. Bajo esta premisa parece natural examinar la organización de la tierra utilizando variables de tipo fisiológico. Aquí identificamos algunas de las principales variables del sistema circulatorio oceánico: tasa de bombeo del corazón, volumen de latido, diferencias arteriovenosas de carbono y nutrientes, suministro de carbono y nutrientes inorgánicos, y tasa metabólica. El volumen de latido es proporcional al transporte de agua hacia la termoclina y océano profundo, y las diferencias arterio-venosas ocurren entre las aguas profundas recientemente afloradas y aquellas altamente productivas de altas latitudes, con el CO2 atmosférico siendo un indicador de la diferencia arterio-venosa de carbono inorgánico. La tasa metabólica es el flujo de energía interna (aquí expresado como flujo de carbono inorgánico en el océano superior) requerido por la maquinaria que sostiene el sistema, i.e. respiración total de la comunidad. Se propone que la tasa de latido está impuesta externamente, un latido por año por hemisferio, y que el océano autotrófico ajusta su volumen de latido y las diferencias arteriovenosas a cambios en la demanda de energía interna, inducido por ciclos de insolación astronómica de largo período (suministro de energía externa). Bajo esta perspectiva podemos concebir que el ciclo interglacial-glacial de la tierra responde a una organización interna análoga a la que ocurre en seres vivos durante un ciclo de ejercicio-recuperación. Se utiliza un modelo metabólico idealizado de dos estados para el océano superior (con el suministro de carbono/nutrientes inorgánicos especificado mediante la tasa de recirculación de aguas profundas y las concentraciones de carbono/nutrientes inorgánicos en estado estacionario) para obtener la evolución temporal de su concentración de carbono inorgánico, la cual mimetiza el patrón glacial-interglacial del CO2 atmosféricoThis work was supported by the Spanish government through the CANOA project (CTM2005-00444/MAR)Peer reviewe

Jejunum free flap in hypopharynx reconstruction: Case series

BACKGROUND: Surgical treatment of hypopharyngeal cancers with extension to the retrocricoid region generally requires a circumferential pharyngolaryngectomy followed by a reconstruction of the removed segment of the upper digestive tract. Historically, many techniques have been used in order to achieve a safe and functional reconstruction. Jejunum interposition is generally considered the best reconstructive technique. METHODS: This study examines the details of the surgical technique, the complications, the oncological and the functional results in a series of 29 consecutive patients submitted to circumferential pharyngoesophageal resection for advanced hypopharyngeal cancer followed by reconstruction with a free flap of jejunum. RESULTS: Three of the transplants failed because of venous thrombosis. The overall success rate was 90%. There were no general complications. A good swallowing has been preserved in all our patients. All our patients where a phonatory prosthesis was positioned (20/29) were able to achieve speech following speech therapy and all were satisfied with their own capacity to communicate. CONCLUSIONS: The prognosis of hypopharyngeal tumours (18–40% at 5 years) remains poor, but jejunum autografts are being shown to be an excellent choice for the reconstruction of the cervical hypopharyngo-oesophagus offering the patient fast rehabilitation and a reasonable quality of survival. Our experience confirm that this kind of reconstruction is safe with a good results in improving oncologic controls and restoring a good quality of life

Oncological outcome after free jejunal flap reconstruction for carcinoma of the hypopharynx

It has been a common practice among the oncologist to reduce the dosage of adjuvant radiotherapy for patients after free jejunal flap reconstruction. The current aims to study potential risk of radiation to the visceral flap and the subsequent oncological outcome. Between 1996 and 2010, consecutive patients with carcinoma of the hypopharynx requiring laryngectomy, circumferential pharyngectomy and post-operative irradiation were recruited. Ninety-six patients were recruited. TNM tumor staging at presentation was: stage II (40.6%), stage III (34.4%) and stage IV (25.0%). Median follow-up period after surgery was 68 months. After tumor ablation, reconstruction was performed using free jejunal flap (60.4%), pectoralis major myocutaneous (PM) flap (31.3%) and free anterolateral thigh (ALT) flap (8.3%). All patients underwent adjuvant radiotherapy within 6.4 weeks after surgery. The mean total dose of radiation given to those receiving cutaneous and jejunal flap reconstruction was 62.2 Gy and 54.8 Gy, respectively. There was no secondary ischaemia or necrosis of the flaps after radiotherapy. The 5-year actuarial loco-regional tumor control for the cutaneous flap and jejunal flap group was: stage II (61 vs. 69%, p = 0.9), stage III (36 vs. 46%, p = 0.2) and stage IV (32 vs. 14%, p = 0.04), respectively. Reduction of radiation dosage in free jejunal group adversely affects the oncological control in stage IV hypopharyngeal carcinoma. In such circumstances, tubed cutaneous flaps are the preferred reconstructive option, so that full-dose radiotherapy can be given

Toward community standards and software for whole-cell modeling

Whole-cell (WC) modeling is a promising tool for biological research, bioengineering, and medicine. However, substantial work remains to create accurate, comprehensive models of complex cells. Methods: We organized the 2015 Whole-Cell Modeling Summer School to teach WC modeling and evaluate the need for new WC modeling standards and software by recoding a recently published WC model in SBML. Results: Our analysis revealed several challenges to representing WC models using the current standards. Conclusion: We, therefore, propose several new WC modeling standards, software, and databases. Significance:We anticipate that these new standards and software will enable more comprehensive models

Imidazol-1-ylethylindazole Voltage-Gated Sodium Channel Ligands Are Neuroprotective during Optic Neuritis in a Mouse Model of Multiple Sclerosis

[Image: see text] A series of imidazol-1-ylethylindazole sodium channel ligands were developed and optimized for sodium channel inhibition and in vitro neuroprotective activity. The molecules exhibited displacement of a radiolabeled sodium channel ligand and selectivity for blockade of the inactivated state of cloned neuronal Na(v) channels. Metabolically stable analogue 6 was able to protect retinal ganglion cells during optic neuritis in a mouse model of multiple sclerosis

Towards an interoperable ecosystem of AI and LT platforms : a roadmap for the implementation of different levels of interoperability

With regard to the wider area of AI/LT platform interoperability, we concentrate on two core aspects: (1) cross-platform search and discovery of resources and services; (2) composition of cross-platform service workflows. We devise five different levels (of increasing complexity) of platform interoperability that we suggest to implement in a wider federation of AI/LT platforms. We illustrate the approach using the five emerging AI/LT platforms AI4EU, ELG, Lynx, QURATOR and SPEAKER

How crossover speeds up evolutionary algorithms for the multi-criteria all-pairs-shortest-path problem

Understanding the impact of crossover in evolutionary algorithms is one of the major challenges in the theoretical analysis of these stochastic search algorithms. Recently, it has been shown that crossover provably helps to speed up evolutionary algorithms for the classical allpairs- shortest path (APSP) problem. In this paper, we extend this approach to the NP-hard multi-criteria APSP problem. Based on rigorous runtime analyses, we point out that crossover leads to better worst case bounds than previous known results. This is the first time that rigorous runtime analyses have shown the usefulness of crossover for an NP-hard multi-criteria optimization problem.Frank Neumann and Madeleine Theil