Failure Modeling: A Basis for Strength Prediction of Lumber

Failure modeling of knot-containing wood members was investigated as a means to predict member tensile strength. A finite element/fracture mechanics model was developed to model the progressive fracture process observed during failure of wood members. The failure modeling process yields predicted tensile strengths for members that contain knots in the wide face. Predicted strengths compared favorably with tensile strength data measured in initial experimental tests. Predicted strengths are generated from basic engineering computation and are not derived or adjusted by any empirical factors. With further research and verification, the concepts presented hold promise for use in lumber grading and quality assurance

Correlative Light and Electron Microscopy of Platelet Adhesion and Fibrinogen Receptor Expression using Colloidal-Gold Labeling

Differences in the shape change responses of platelets to various polymers may determine the thrombotic potential of these materials. Substrate-dependent variation in the expression and motility of the platelet fibrinogen receptor may underlie these differences due to this ligand\u27s essential role in platelet aggregation. In this study we examine platelet activation on polyetherurethaneureas (PEUUs) presently being evaulated for vascular prosthetic applications. These polymers are prepared as 50-100nm thin films suitable as substrates for consecutive light microscopy, high voltage electron microscopy (HVEM), and SEM. 18nm colloidal gold coupled to fibrinogen permits visualization of that receptor\u27s motility in living cells by video-enhanced light microscopy. Subsequent HVEM and SEM of identified cells provides correlative ultrastructure and surface morphology. The use of these novel support films coupled with the multiple modes of microscopy and colloidal gold labeled ligands permits in depth study of the molecular biology of cell adhesion to materials with varied, and known, surface properties. The motility of the platelet fibrinogen receptor was related to the extent of cytoskeletal reorganization, which, in turn, was influenced by polymer surface energetics. Platelets adherent to more hydrophobic PEUUs had greater receptor mobility and receptor redistribution than platelets adherent to more hydrophilic PEUUs. The most extensive receptor motility and redistribution was observed on Formvar, a non-PEUU with low surface-water energy, suggesting that additional surface properties are of importance in determining platelet spreading and fibrinogen receptor motility

Aperçu sur la fragmentation de la forêt naturelle dans la Réserve Spéciale d’Ambohitantely et ses alentours entre 1949 et 2017, Hautes Terres Centrales

Cette étude vise à caractériser la dynamique de la couverture forestière et la fragmentation de la forêt naturelle de la Réserve Spéciale d’Ambohitantely et les zones périphériques dans un rayon de 10 km de la limite de l’aire protégée entre 1949 et 2017. Au total, cinq images satellitaires pour les années 1989, 1995, 2002, 2010 et 2017, et 59 clichés de photographies aériennes prises en 1949 ont été utilisées. La télédétection et le système d’information géographique ont été utilisés pour la cartographie de l’occupation du sol pour les six périodes d’études, ainsi que pour l’analyse de la dynamique de la couverture forestière et l’estimation de la perte de surface forestière. Six métriques disponibles sur le logiciel FRAGSTATS ont été sélectionnées pour l’analyse de la fragmentation à l’échelle du paysage à savoir, le nombre de parcelles (NP), la densité de parcelles (PD), la variabilité de la taille des parcelles (AREA_SD), l’indice de la dimension fractale (FRAC_MN), l’indice de contiguïté (CONTIG_MN) et l’indice d’agrégation (AI). Après une classification supervisée, les classes d’occupation du sol ont été reclassées en forêt ou non-forêt. La dynamique de la couverture forestière dans la zone étudiée a montré qu’une vaste zone forestière a été convertie en zone non forestière. L’estimation de la perte de forêt indique que le taux annuel dans la réserve varie, et la plus importante estimée à 586,4 ha soit 4,05% par an a été enregistrée entre 1995 et 2002, et la plus faible est de 473,4 ha soit 0,41% par an, entre 1949 et 1989. Les résultats ont montré la diminution du nombre de fragments ainsi que la densité des fragments depuis 1989 à 2017, ce qui indique la disparition de fragments forestiers. En parallèle, la réduction de l’indice de la dimension fractale et de la variabilité de la taille des parcelles révèlent la simplification de la forme des fragments et la faible diversification de la superficie des différents fragments. L’augmentation de l’indice d’agrégation contre la diminution de l’indice de contiguïté confirme l’isolement des fragments.  AbstractThis study aims to characterize the dynamics of forest cover and fragmentation of the natural forest of the Ambohitantely Special Reserve between 1949 and 2017 and within a radius of 10 km of the boundary limit. Five different periods of satellite images were employed, specifically the years 1989, 1995, 2002, 2010, and 2017, as well as aerial photographs taken in 1949. Remote sensing and geographic information systems were used for land cover mapping for the six study periods, as well as for analyzing forest cover dynamics and estimating forest cover loss. Using the software FRAGSTATS, six different metrics were selected for the analysis of forest fragmentation at the landscape level: number of patches (NP), patch density (PD), patch size standard deviation (AREA_SD), mean patch fractal dimension (FRAC_MN), contiguity index (CONTIG_MN), and aggregation index (AI). Following a supervised classification, land cover classes were reclassified as forest or non-forest. The dynamics of forest cover at the site and over the study period indicated that considerable zones of forest were transformed to non-forested areas. The estimate of forest loss indicates that the annual rate in the reserve varies, and the largest estimated at 586.4 ha or 4.05% per year was recorded between 1995 and 2002, and the lowest is 473.4 ha or 0.41% between 1949 and 1989. The results indicate a decrease in the number of fragments as well as the density of fragments from 1989 to 2017 associated with the disappearance of forest. In parallel, the reduction of the mean patch fractal dimension and variability of the patch size denotes the simplification of the fragments’ shapes and the slight diversification of the areas of the different fragments. An increase in the aggregation index as compared to a decrease in the contiguity index confirms the isolation of the fragments

Predation by the grey leaf monkey ( Presbytis hosei ) on the contents of a Bird's nest at Mt. Kinabalu Park, Sabah

An adult male grey leaf monkey ( Presbytis hosei ) was observed in Mt. Kinabalu Park, Sabah, Malaysia, raiding the nest of a grey-throated babbler ( Stachyris nigriceps ). The monkey removed from the nest and ate at least two eggs and perhaps one young hatchling. This incident appears to be the first reported case of any Presbytis spp. consuming animal prey.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/41605/1/10329_2006_Article_BF02381220.pd

The birds of the Egyptian western desert

http://deepblue.lib.umich.edu/bitstream/2027.42/56416/1/MP172.pd

Diversity and longitudinal species turnover of small mammals in the forests of watersheds of western Madagascar

The species diversity of Malagasy small mammals is assessed along three different east-west flowing rivers passing through different forest formations and of different length: Soahany (short river), Manambolo (medium-length river), and the Mangoky (long river). The levels of species replacement (β-diversity) are evaluated along these three different longitudinal gradients. Twenty-two sites were inventoried, six along the Soahany River, five along the Manambolo River, and 11 along the Mangoky River. Thirty-five species of small mammals were documented at these sites, composed of 21 species of endemic Afrosoricida (Tenrecidae); two species of Soricomorpha including one endemic (Suncus madagascariensis) and one introduced (S. murinus); and 12 species of Rodentia including 10 endemics (Nesomyidae) and two introduced species (Rattus rattus and Mus musculus). There was a correlation between species richness and the length of each river basin: Mangoky has the greatest species richness (29 taxa), followed by the Manambolo (11 taxa) and the Soahany (10 taxa). α-diversity augments with increasing habitat complexity and surface area. Humid forest sites in the central highlands near the Zomandao River (the source of the Mangoky) possess high α-diversity. For dry forest sites, those towards the interior in relatively large forested areas have greater α-diversity measures than those of smaller or coastal forest sites. β-diversity augments along the river systems with increasing habitat heterogeneity. The transect along the Soahany River has the highest β-diversity values, indicating higher levels of species turnover than the other two river systemsDans des sites situés le long de trois fleuves de différentes longueurs, coulant d'est en ouest vers le Canal de Mozambique (Soahany [fleuve court], Manambolo [fleuve de longueur moyenne] et Mangoky [fleuve long]), avec différents types des forêts, ont été évalués d'une part la diversité locale des petits mammifères et d'autre part le taux de remplacement des espèces suivant un gradient longitudinal. Vingt-deux sites ont été inventoriés dont six le long du Soahany, cinq pour le Manambolo et 11 le long du Mangoky. Au total 35 espèces de petits mammifères ont été recensées le long de ces transects dont 21 espèces endémiques d'Afrosoricida (Tenrecidae), deux espèces de Soricomorpha dont une endémique (Suncus madagascariensis) et une allogène (S. murinus) et 12 espèces de Rodentia dont 10 endémiques (Nesomyidae) et deux allogènes (Rattus rattus et Mus musculus). Il semblerait que la richesse spécifique varie proportionnellement avec la longueur de chaque transect: Mangoky est le plus riche (29 espèces) suivi de Manambolo (11 espèces) et de Soahany (10 espèces). La diversité α augmente avec le type d'habitat, sa superficie et sa complexité. Les sites des forêts humides situés dans le haut plateau central du côté de la rivière Zomandao (source du Mangoky) possèdent une diversité a élevée. Pour les sites des forêts sèches, ceux situés à l'intérieur des blocs forestiers de larges étendues ont la diversité α la plus élevée. La diversité β augmente avec l'hétérogénéité des habitats le long de chaque transect. Le transect Soahany, le plus court, possède la diversité β la plus élevée, traduisant un taux de remplacement d'espèce plus rapide que ceux des deux autres transects

The GOES-R Series Geostationary Lightning Mapper (GLM)

The Geostationary Operational Environmental Satellite (GOES-R) is the next series to follow the existing GOES system currently operating over the Western Hemisphere. Superior spacecraft and instrument technology will support expanded detection of environmental phenomena, resulting in more timely and accurate forecasts and warnings. Advancements over current GOES capabilities include a new capability for total lightning detection (cloud and cloud-to-ground flashes) from the Geostationary Lightning Mapper (GLM), which will have just completed Critical Design Review and move forward into the construction phase of instrument development. The GLM will operate continuously day and night with near-uniform spatial resolution of 8 km with a product refresh rate of less than 20 sec over the Americas and adjacent oceanic regions. This will aid in forecasting severe storms and tornado activity, and convective weather impacts on aviation safety and efficiency. In parallel with the instrument development (an engineering development unit and 4 flight models), a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 algorithms, cal/val performance monitoring tools, and new applications. Proxy total lightning data from the NASA Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional ground-based lightning networks are being used to develop the pre-launch algorithms, test data sets, and applications, as well as improve our knowledge of thunderstorm initiation and evolution. In this presentation we review the planned implementation of the instrument and suite of operational algorithm

Description and Status of the DC Lightning Mapping Array

The DC Lightning Mapping Array (DC LMA) centered on the Washington, DC metro region has been in operation since 2006. During that time the DC LMA has provided real time data to regional National Weather Service (NSF) Sterling, VA forecast office for operations support and the NOAA Meteorological Development Laboratory (MDL) for new product development and assessment. Data from this network (as well as other from other LMA systems) are now being used to create proxy Geostationary Lightning Mapper (GLM) data sets for GOES-R risk reduction and algorithm development activities. In addition, since spring 2009 data are provided to the Storm Prediction Center in support of Hazardous Weather Testbed and GOES-R Proving Ground activities during the Spring Program. Description, status and plans will be discussed