Micro-connectomics: probing the organization of neuronal networks at the cellular scale.

Defining the organizational principles of neuronal networks at the cellular scale, or micro-connectomics, is a key challenge of modern neuroscience. In this Review, we focus on graph theoretical parameters of micro-connectome topology, often informed by economical principles that conceptually originated with Ramón y Cajal's conservation laws. First, we summarize results from studies in intact small organisms and in samples from larger nervous systems. We then evaluate the evidence for an economical trade-off between biological cost and functional value in the organization of neuronal networks. Various results suggest that many aspects of neuronal network organization are indeed the outcome of competition between these two fundamental selection pressures.This work was supported by the National Institute of Health Research (NIHR) Cambridge Biomedical Research Centre.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Nature Publishing Group

Airflow attenuation and bed net utilization: observations from Africa and Asia

<p>Abstract</p> <p>Background/Methods</p> <p>Qualitative studies suggest that bed nets affect the thermal comfort of users. To understand and reduce this discomfort the effect of bed nets on temperature, humidity, and airflow was measured in rural homes in Asia and Africa, as well as in an experimental wind tunnel. Two investigators with architectural training selected 60 houses in The Gambia, Tanzania, Philippines, and Thailand. Data-loggers were used to measure indoor temperatures in hourly intervals over a 12 months period. In a subgroup of 20 houses airflow, temperature and humidity were measured at five-minute intervals for one night from 21.00 to 6.00 hrs inside and outside of bed nets using sensors and omni-directional thermo-anemometers. An investigator set up a bed net with a mesh size of 220 holes per inch² in each study household and slept under the bed net to simulate a realistic environment. The attenuation of airflow caused by bed nets of different mesh sizes was also measured in an experimental wind tunnel.</p> <p>Results</p> <p>The highest indoor temperatures (49.0 C) were measured in The Gambia. During the hottest months of the year the mean temperature at night (9 pm) was between 33.1 C (The Gambia) and 26.2 C (Thailand). The bed net attenuated the airflow from a minimum of 27% (Philippines) to a maximum of 71% (The Gambia). Overall the bed nets reduced airflow compared to un-attenuated airflow from 9 to 4 cm sec^-1 or 52% (p < 0.001). In all sites, no statistically significant difference in temperature or humidity was detected between the inside and outside of the bed net. Wind tunnel experiments with 11 different mesh-sized bed nets showed an overall reduction in airflow of 64% (range 55 - 71%) compared to un-attenuated airflow. As expected, airflow decreased with increasing net mesh size. Nets with a mesh of 136 holes inch^-2 reduced airflow by 55% (mean; range 51 - 73%). A denser net (200 holes inch^-2) attenuated airflow by 59% (mean; range 56 - 74%).</p> <p>Discussion</p> <p>Despite concerted efforts to increase the uptake of this intervention in many areas uptake remains poor. Bed nets reduce airflow, but have no influence on temperature and humidity. The discomfort associated with bed nets is likely to be most intolerable during the hottest and most humid period of the year, which frequently coincides with the peak of malaria vector densities and the force of pathogen transmission.</p> <p>Conclusions</p> <p>These observations suggest thermal discomfort is a factor limiting bed net use and open a range of architectural possibilities to overcome this limitation.</p

Geo-Climatic Indicators to Define Local Potential of Low-Energy Technologies Including Climate Changes

This chapter deals with a geo-climatic approach to low-energy technologies in climate change scenarios. Different key performance indicators (KPI) which are able to predict the geo-climatic potential distribution of bioclimatic solutions in reducing expected energy needs while guaranteeing space comfort in buildings (e.g. wind-driven, controlled natural ventilation for passive cooling of spaces) are described. This approach is further expanded to define the resilience of the above mentioned techniques in absorbing climate change impact on cooling and heating needs. The main objective of the chapter is to describe a methodological approach and introduce the aims of the geo-climatic vision. Three bioclimatic technologies based on low-energy/passive cooling (direct evaporative cooling, earth-to-air heat exchangers, wind-driven ventilation) and one low-energy/passive heating (earth-to-air heat exchangers), are taken as references. The calculation results of the local potential of these technologies based on related KPIs are described for the entire Italian peninsula, assuming both current typical meteorological years and two future climate change scenarios