Different Degrees Of Fragmentation Research Articles

A prestressed anchor-grouting reinforcement method based on the novel HFQSME grouting material for deep high-stress fractured rock mass

In order to control the surrounding rock of deep high-stress roadways, a new prestressed anchor-grouting reinforcement method was proposed with an engineering background of the 1780 ventilation roadway of Shiyakou Coal Mine. A high-fluidity quick-setting micro-expansion (HFQSME) grouting material had been developed through superplasticizer, accelerator, and expansion agent. The results showed that the optimal ratio of HFQSME grouting material was superfine Portland cement of 95%, superplasticizer of 0.5%, accelerator agent of 0.5%, expansion agent of 5.0%, and water-binder ratio of 0.4. The fluidity, initial setting time and expansion rate of the grouting material were 47cm, 41minutes and 0.12%, respectively. The grouting reinforcement effect of superfine slurry and HFQSME grouting material on rock mass with different degrees of fragmentation was investigated. The peak strength of rock mass with two degrees of fragmentation reinforced by HFQSME grouting material was 166% and 233% higher than that of superfine slurry. The macro reinforcement effect of HFQSME grouting material on the surrounding rock of deep high-stress roadway was evaluated through industrial testing. The prestressed anchor grouting method was used to improve the original support design scheme, and data monitoring and analysis were conducted on site. Compared with the original supporting scheme, the deformation of the 1780 ventilation was significantly reduced. Therefore, HFQSME grouting material had good adaptability for the surrounding rock of deep high-stress roadways.

Field evidence and indicators of rockfall fragmentation and implications for mobility

Rockfall fragmentation can play an important role in hazard studies and the design of protective measures. However, the current lack of modeling tools that incorporate rock fragmentation mechanics is a limitation to enhancing studies and design. This research investigates the fragmentation patterns of rockfalls and analyzes the resulting distribution of fragment sizes within corresponding rockfall deposits. We focus on small rock fragments, which provide insights into the dynamics of the rockfall event and can be used as input for numerical modeling. We analyzed multiple rockfall events from locations worldwide, each exhibiting different degrees of fragmentation. Using image analysis techniques, we mapped all visible blocks, determined their volumes, and measured the distances they travelled from the initial point of impact. A key finding is the identification of three indicators of fragmentation. First, in cases where fragmentation was largely absent, we observed a trend of increasing block size with distance from the impact point or source area, which aligns with previously published findings. However, for energetic rockfall events characterized by intense fragmentation, we observed that small fragments exhibited longer travel distances compared to larger fragments. This distinction allowed us to differentiate blocks primarily resulting from the disaggregation process from those primarily resulting from dynamic fragmentation, with implications for rockfall mobility. Second, although the size distribution of rockfall deposits exhibits a power-law scaling for volumes larger than a minimum size threshold corresponding to a rollover of the distribution, in some case studies a deviation from power-law scaling is observed, indicating a process of larger block comminution due to fragmentation. Third, we found that rockfalls with fragmentation experience reduced mobility, indicated by higher reach angles, and higher lateral dispersion showing a wider distribution of trajectories. We interpret these findings as being directly related to the energy-consuming nature of fragmentation, which prevents farther deposition of fragmented rock blocks.

A New Paradigm for Assessing Detailed Dynamics of Forest Landscape Fragmentation

There is an urgent need for a thorough assessment of forest landscape fragmentation to inform forest protection and restoration, and reforestation policies. However, there is currently a lack of an effective comprehensive index for forest landscape fragmentation, and detailed knowledge of the forest landscape fragmentation dynamics remains insufficient. Here, taking Putian City of Fujian Province in Southeastern China as a case, we employed a forest fragmentation comprehensive index (FFCI) to capture key features of forest landscape fragmentation, such as patch size, number, and distribution. Then, bivariate spatial autocorrelation analysis was employed to identify the spatial associations between the static forest landscape fragmentation (FFCI) and the dynamic forest landscape fragmentation (ΔFFCI), and the spatial coupling modes among the three individual components of FFCI (mean patch area, MPA; aggregation index, AI; patch density, PD) were identified to explore the detail process of forest landscape fragmentation. Finally, the random forest model was applied to observe the impact factors of forest landscape fragmentation dynamics. The findings showed that forest landscapes with different degrees of fragmentation exhibited more noticeable changes at both ends (i.e., either high or lower-level fragmentation), with the intermediate level remaining consistent from 2000 to 2020. Around 18.3% of forest landscapes experienced a decrease in fragmentation, particularly in the northern part of the study area, while approximately 81.7% of forest landscapes exhibited an increasing trend in fragmentation. The bivariate spatial autocorrelation analysis indicated that the proportion of Low–High-type grids was the highest at 17.3%, followed by the High–High type at 7.0%. We also identified eight forest landscape fragmentation modes, which indicate the most significant forest landscape fragmentation pattern is a decrease in MPA and an increase in PD. Moreover, the anthropogenic factors (e.g., population density and night light intensity) were found to dominate the FFCI dynamics during 2000–2020. This study offers an efficient research paradigm for the dynamics of forest landscape fragmentation. The outcomes are conducive to an in-depth comprehension of the detailed dynamic information of forest landscape fragmentation, and supply a scientific foundation for enhancing the overall ecological service function of the forest.

Diets of white-headed langurs (Trachypithecus leucocephalus) inhabiting limestone forests: The effects of habitat fragmentation and implication for conservation.

Information about wildlife diets is crucial for comprehending how species adapt to varying environments in fragmented habitats and for developing effective conservation strategies. White-headed langurs (Trachypithecus leucocephalus) are exclusively found in fragmented limestone forests in southwestern China. To investigate the effects of habitat fragmentation on langurs' diets, we collected published dietary data and relevant environmental factors spanning from 1996 to 2021 at two regions with different degrees of fragmentation (Banli > Bapen), from 10 studies (three of Banli and seven of Bapen). The results demonstrated that the diets of white-headed langurs were significantly influenced by environmental factors, including habitat fragmentation, annual rainfall, and mean annual temperature. Food item diversity index was significantly and positively affected by the fragmentation index, the higher fragmentation the langurs suffered, the more diverse food items they consumed. Besides, fruit consumption was negatively influenced by annual rainfall and the consumption of other items was influenced by mean annual temperature. Notably, although there are no significant differences in the feeding proportions of food items or food item diversity indices were observed between the Banli and Bapen groups, the Banli groups extensively consumed ground-supported kudzu (Pueraria montana var. lobata), a plant rarely recorded in the dietary preferences of the Bapen groups, implying that the large plants likely lacking in the fragmented limestone forests. Our findings provide evidence of the major impact of habitat fragmentation on the dietary composition of white-headed langurs, highlighting the need of considering the possibility that the habitats of the white-headed langurs have all undergone extreme fragmentation, inferring the conservation efforts should prioritize protecting native vegetation and reducing human disturbance.

Analysis of volatile components in different broken rice by HS‐SPME/GC‐TOFMS

AbstractIn this study, headspace solid‐phase microextraction (HS‐SPME) combined with gas chromatography‐time‐of‐flight mass spectrometry (GC‐TOFMS) was used to detect and analyse the volatile components of five samples with different degrees of fragmentation, combined with cluster analysis, orthogonal partial least squares discrimination analysis (OPLS‐DA) and relative odour activity value (ROAV) analysis. The results showed that 70 volatile components were detected and identified in samples with different degrees of fragmentation. 40 were co‐containing components. Cluster analysis revealed a high degree of similarity between samples B (20 mesh sieve top) and C (40 mesh sieve top), which were grouped into one category. The order of variation in the relative content of volatile components was A (unbroken) > E (120 mesh sieve top) > D (80 mesh sieve top) > B. C; the OPLS‐DA analysis revealed significant differences in the volatile composition of rice samples with different degrees of fragmentation, This variation between samples is mainly due to the relative content of volatile components of 36 projections of variable importance (VIP > 1), such as ethyl butyrate, ethyl phenylacetate, and dimethyl trisulfide. A total of 12 volatile components with ROAV > 1, including ethyl hexanoate, 2‐acetyl‐1‐pyrroline, and E‐2‐nonenal, were found to be the key volatile components in five samples based on their ROAV, the different degrees of crushing had a greater impact on the overall aroma of the rice, and the results can be used as a reference for further rice processors.

Population structure, aggregation, and dispersal of Euterpe edulis Mart. at two sites of interior atlantic forest.

Habitat destruction and fragmentation can change environmental conditions and disrupt mutualistic interactions, leading to impacts on natural populations. Here we checked how plant population structure responds to environmental degradation by quantifying effective seed dispersal and patterns of population distribution for the animal-dispersed palm Euterpe edulis Mart. (Arecaceae). Thus, we assessed E. edulis population structure at two locations with different degrees of fragmentation in the Interior Atlantic Forest (west of the State of Paraná, Brazil), where we registered the density of saplings at increasing distances from adults palms and from large trees in the vicinity (perch-trees). We found differences between locations, with aggregated saplings and highest densities at the most fragmented site, although in this site Immature individuals were almost absent. We also identified patches of saplings under perch-trees canopies, in a way which suggests these individuals originate from dispersal events. In both sites, the abundance of Immature saplings was similar either nearby adult palms or perch-trees, pointing to perch-trees being relevant to E. edulis population dynamics. Thus, while conservation of E. edulis in the Interior Atlantic Forest can benefit from such new data, it is still necessary to check whether our findings are recurring and consistently found elsewhere.

Effects of habitat fragmentation on the recruitment and early post-settlement survival of coral reef fishes

The combined effects of global climate change and local anthropogenic stressors are leading to increasing loss and fragmentation of habitats. On coral reefs, habitat loss has been shown to influence the abundance and composition of associated fish assemblages, yet few studies have considered how habitat fragmentation may influence reef fish populations and assemblages. Herein, we compared survival, growth and recruitment of reef fish among experimental patches composed of six similar sized colonies of finely branching Pocillopora spp. but with different degrees of fragmentation: coral colonies were clumped (unfragmented), divided into two groups (low fragmentation), three groups (moderate fragmentation) or six groups (high fragmentation). Thirty settlement-stage Pomacentrus amboinensis were tagged, released onto each of the experimental patches, and their survival monitored daily for 11 days. Abundance and species richness of all reef fishes that subsequently recruited to the patches were also recorded, and used to analyse recruitment and community composition. There were no detectable differences among fragmentation treatments in the abundance or composition of reef fish assemblages that recruited to the patches, however, fragmentation influenced the survivorship of P. amboinensis. Highest survival of P. amboinensis was recorded on the unfragmented patches (61%.11 days−1) and highly fragmented habitat patches (54%.11 days−1) and lowest survival on low and moderate fragmentation treatments (47% and 48%.11 days−1, respectively). This suggests that there may be multiple competing processes that moderate mortality (e.g., predation) in unfragmented versus highly fragmented habitats, with moderate levels of habitat fragmentation having the greatest influence on the early post-settlement survival of corsal reef fish.

Morphosedimentological features of the sea floor in the outer sector of the Bahia Blanca estuary, Argentina

The purpose of this paper is to analyze the morphology of the Quaternary relict features and bedforms that characterize the outer zone of an extensive mesomareal system, which is part of the Bahía Blanca estuary (Argentina), and to estimate the prevailing hydro-sedimentological conditions on the continental shelf adjacent to the estuary. Surveys with a multibeam bathymetric system, side-scan sonar and a high-resolution seismic system (3.5 kHz) were carried out and bottom sediment samples were collected. In general, the seafloor presents a varied configuration, marked by changes in its physiography. The Quaternary relict features are composed of two terraces (12–14 m and 18–22 m deep), with steeply sloping escarpments, that are oriented approximately parallel to the current coastline. Associated with these terraces, wide abrasion platforms develop with irregular and plateau-like structures up to 4 m high, together with large rocky blocks up to 6 m in diameter. Here, the predominant sediment corresponds to a gravel-sized material composed of quartzite boulders, siltstone fragments of up to 7 cm, and biogenic remains with different degrees of fragmentation. These sedimentological data, together with the bathymetric and seismostratigraphic information, indicate that the terraces and abrasion platforms are ancient shorelines that originated in an environment with high wave energy, corresponding to periods of stabilization of sea level rise during the final stage of the last postglacial transgression (late Pleistocene-Early Holocene). On the other hand, asymmetric dunes of different sizes (0.5 m < height < 5 m, 5 m < wavelength < 200 m), sand ribbons (length > 300 m) and comet marks originated in equilibrium with the present-day hydro-sedimentological conditions. The availability of sandy material mobilized as bedload is the determining factor for the generation of the varied bedforms. Thus, sand ribbons and comet marks are generated especially in the northern sector of the area, with mobile sediment thicknesses ≤ 0.5 m. With larger thicknesses the formation of dunes occurs. Their size and asymmetry show an intense transport of sand as bedload towards the continental shelf, the southern sector of the area being the main route of the sediment that leaves the estuary. This sediment is the supply source of the sandy shoals that are part of the great ebb delta developed on the continental shelf in the external area of the Bahía Blanca estuary.

Insights into the Strain Rate on Microstructure Evolution of Carbide‐Free Bainitic Steel

The microstructural transformation behavior of carbide-free bainitic steel at different strain rates is investigated using a combination of scanning electron microscopy, transmission electron microscopy, and electron backscatter diffraction. The results demonstrate that the stress–strain relationship of the steel exhibits a dependence on the strain rate, with the tensile strength increasing from 1441 MPa at a strain of 0.1 s−1 to 1537 MPa at 500 s−1, with the elongation of the sample increasing from 16.0% to 22.0% under these conditions. The increase in the strain rate raises the degree of local deformation with blocky martensite/retained austenite, exhibiting that different degrees of fragmentation and bainitic ferrite laths are observed to undergo torsional deformation. Through continuous dislocation absorption, the dislocation walls and dislocation tangles gradually develop into low-angle subgrain boundaries, primarily located in regions with high kernel average misorientation values. After deformation at a strain rate of 0.1 s−1, the sample exhibits a Brass texture and demonstrates a combination of both Brass + Goss textures at a strain rate of 500 s−1.

On the question of determining the quantity of energy necessary for the disintegra-tion of rocks to a certain size

An analysis of the existing classical theories of determining the amount of energy re-quired for the disintegration of solid bodies is carried out. The classical energy hypothe-ses of the destruction of Rittinger, Kick-Kirpychev and Bond can be combined by the formula of the so-called generalizing hypothesis , where E1 is the specific energy transmitted per unit volume of the body , which is collapsing. It is necessary to increase the energy of the newly created surface; k - proportionality factor; x - average grain diameter; f(x) is an exponent that depends on the size of the particles. The geo-metric interpretation of the generalizing hypothesis and theoretical and empirical equa-tions of Rittinger, Kick, Kirpychov, Bond, Svensson, Holmes and other authors is shown and it is argued that they complement each other for different degrees of fragmentation. The thermodynamic theory of L. Jingezian and the theory of A. Andreazen are also ana-lyzed. It was concluded that the presented crushing hypotheses are valid for simplified models of destruction based on the geometric similarity of the particles that are de-stroyed and the products of destruction and their physical identity, in the absence of de-fects in the structure of bodies, therefore the need to create a generalized and reliable mathematical model that reveals the main regularities of these processes taking into account the share of internal and especially external friction. The authors, under the guidance of Professor Vasiliev L.M. a new theory of local destruction of rock with symmetric and asymmetric distribution of contact tangential stresses has been developed, which theoretically provides a reduction in the specific en-ergy of destruction by 40-45 times, which makes it possible to search for new ways of controlling the disintegration process with the lowest energy consumption.

Analysis of landscape spatial pattern changes in urban fringe area: a case study of Hunhe Niaodao Area in Shenyang City

The urban fringe is areas where land use changes and develops rapidly, analyzing land use changes and driving forces in urban fringe area is of great significance for landscape pattern and ecological environment construction. This study takes the Hunhe Bird Island area of Shenyang City as the research object, uses Landsat remote sensing images from 2005 to 2019 as the basic data, and uses the land transfer matrix and landscape index method to analyze the overall landscape environment and six land types. Using government policies and statistical data to analyze the driving forces of landscape changes. The research results show that the landscape matrix had changed, the overall landscape structure had changed drastically, the ecological environment was unstable, and human interference factors had increased, and the fragmentation phenomenon had become more and more serious. Each land type has different environmental changes. Except for the relatively stable water environment, other land types have different degrees of fragmentation. The reason is that the driving force of landscape pattern changes mainly comes from the influence of human factors, which is closely related to population, economic development and government policies. Therefore, future development and protection strategies are proposed for each land type in the urban fringe area. For the overall development of urban fringe area, it is advocated to make full use of land resources, strengthen the correct judgment and forecast of urban population and economy, formulate the correct urban boundary strategy for sustainable development, avoid the ecological environment problems faced by excessive land development, and realize the “Rational expansion” of cities.

The longest fragment drives fish beta diversity in fragmented river networks: Implications for river management and conservation

Connectivity plays a crucial role in maintaining the structural and functional attributes of river networks. Therefore, the loss of connectivity (fragmentation) alters the functioning and diversity patterns of the biota at local and regional scales. The global hydropower boom is one of the main drivers of river network fragmentation, with significant effects on the diversity of riverine biota. Analyses of beta diversity of fish assemblages in rivers with different degrees of fragmentation can give new insights into mechanisms that contribute to the responses of these assemblages to fragmentation.Here, fish beta diversity within six river networks of central Chile with different levels of fragmentation was studied to assess the responses of fish assemblages to fragmentation. A hypothesis of a significant effect of fragmentation on the beta diversity of native and non-native fish in riffles and pools was tested. This effect is expected to be modulated by both changes in environmental heterogeneity and direct obstruction of natural dispersal routes.Beta diversity based on variation of assemblage structure and environmental heterogeneity showed significant differences among river networks. Fish beta diversity showed a clear response to fragmentation in recently fragmented rivers. Specifically, the beta diversity of native fishes in pools and non-native fishes in riffles decreased with increase of the ratio between the longest non-fragmented sections of the river network to the total length of the network. These effects of fragmentation on fish assemblages were modulated by the biological features of each species, and open-water species were most severely affected.These results have significant implications for planning of the placement of new barriers in river networks subjected to hydropower boom. Planning of the placement of new barriers should consider the maintenance of long, connected sections within river networks in order to minimise the effects of fragmentation on fish biodiversity.

Habitat fragmentation restricts insect pollinators and pollen quality in a threatened Proteaceae species

•Disruption of pollination services has been investigated in many species; however, fragmentation-induced effects on endemic plants that rely on species-specific invertebrate pollinators are still unclear. While honeybees can forage over long distances, many native bees with small body size are unable to extend their foraging range, making habitat fragmentation the largest threat to such systems.•Here, we defined the pollinator assemblage of our target species, Conospermum undulatum (Proteaceae), among remnant populations characterized by different degrees of fragmentation. We explored the impact of fragmentation on flower visitation in eleven populations of C. undulatum. Lastly, we took advantage of the fragmentation gradient to tease apart the influences of pollen quantity and quality on pollen limitation.•Small populations showed an impoverished pool of weakly effective pollinators. Flower visitation increased from 1.5% to 74.3% with increasing floral display index, while it increased from 1.3% to 5.6% with increasing connectivity levels of populations. We found evidence of pollen quantity limitation across all the populations; however, the overall pollen limitation was greater in small fragments where genetic factors limited the quality of pollen.•Native bees were absent in small isolated remnants. Our study highlights the importance of such pollinators for plants that coevolved with them. The availability of compatible pollen is limited in small remnant populations and native pollinators appeared unable to maintain an adequate inter-population pollen flow in heavily fragmented landscapes. The effects of habitat fragmentation can be exacerbated in small and isolated populations of plants that rely on species-specific pollinators for sexual reproduction.

Stratigraphy and evolution of the Holocene Aljojuca Maar volcano (Serdán-Oriental basin, Eastern Trans-Mexican Volcanic Belt), and implications for hazard assessment

Aljojuca maar is located in the eastern Trans-Mexican Volcanic Belt, within the Serdán-Oriental Basin, which is characterized by Quaternary bimodal monogenetic volcanism. Aljojuca maar has an irregular shape, with an eastern embayment structure that forms an E-W alignment with at least three older scoria cones to the east. The crater walls expose a sequence of pre-maar volcaniclastic deposits, with a lava flow linked to the older scoria cones and a paleosol at its top; the latter indicates that a significant hiatus occurred between the growth of the scoria cones and the eruption of the Aljojuca maar, whose deposits overlie the soil. Strong interactions of the ascending magma with groundwater led to the emplacement of a ~30-m-thick maar sequence. Our detailed stratigraphic study shows that the eruption can be grouped into two main stages, comprising eight stratigraphic units deposited during five eruptive phases. The first stage reflects the development of the main crater (a maar sensu stricto) and is recorded by six stratigraphic units (from A to F). The eruption began with a strombolian pulse, followed by phreatomagmatic activity (unit A), forming dilute pyroclastic density currents. In the second phase, phreatomagmatic explosions prevailed with different degrees of fragmentation, from juvenile and lithic-rich lapilli fallout (unit B), to less diluted pyroclastic density currents (unit C), and a spatially restricted strombolian pulse. The third phase includes a main-vent enlargement event represented by a chaotic and heterolithic breccia (unit D). In the fourth phase, dilute pyroclastic density current deposits (unit E) dominate, with minor chaotic breccias (unit F). The second stage (fifth phase) includes the occurrence of a possibly fissural E-W structure, which formed a scallop in the eastern flank of the maar (eastern embayment structure), breaking the previously formed main crater's eastern flank and producing a 4-m-chaotic breccia (unit G) followed by the occurrence of a dilute pyroclastic density current (unit H), whose energy enabled the current to climb to the closest scoria cone. The migration of the explosive loci toward the eastern flank of the maar reflects a tectonic control by the dominant regional east-trending structural pattern. Several radiocarbon ages support that the eruption of Aljojuca took place between 2.7 ka (age of charcoal fragments under the ejecta ring) and ~2.2 ka (age of the oldest lake sediments in the maar crater). This has important implications for the hazard assessment of volcanism in this area, which had not been considered previously as a potentially active system.

Evaluation of Microbiological Contamination of Black and Green Teas

The study aimed to determine the level of microbial contamination of black and green teas with different degrees of fragmentation. The microbiological analysis we conducted on 18 black and green teas available commercially on the market. Solutions were prepared from the weighed samples and then inoculated on sterile microbial media. Teas in bags proved to be the most polluted among the tested tea groups. Statistical analysis indicated significant differences in mycological contamination between black and green teas of various degrees of fragmentation. Green tea in bags manifested the highest fungal contamination - 9.3×10³ CFU/g, significantly exceeding the other teas. Isolated fungi belonged to <em>Aspergillus</em> sp., <em>Cryptococcus</em> sp., <em>Rhizopus</em> sp., <em>Mucor</em> sp., </em>Penicillium</em> sp. and <em>Cladosporium</em> sp. The lowest number of fungi we observed in the group of green leaf teas -1.7×10² CFU/g. We recorded the most significant amount of Gram-positive bacteria in deciduous black tea - 1.8×10³ CFU/g. The correlation between the degree of tea fragmentation and their microbial contamination has been demonstrated. Potentially pathogenic bacteria isolated from black and green tea can pose a threat to the health of consumers.

Prevalence of Plasmodium parasites in non-human primates and mosquitoes in areas with different degrees of fragmentation in Colombia

BackgroundParasites from the genus Plasmodium, the aetiological agent of malaria in humans, can also infect non-human primates (NHP), increasing the potential risk of zoonotic transmission with its associated global public health concerns. In Colombia, there are no recent studies on Plasmodium spp. infecting free-ranging NHP. Thus, this study aimed to determine the diversity of Plasmodium species circulating in fragmented forests in central Colombia, both in Anopheles mosquitoes and in the four sympatric NHP in the region (Ateles hybridus, Cebus versicolor, Alouatta seniculus and Aotus griseimembra), in order to evaluate the risk of infection to humans associated with the presence of sylvatic hosts and vectors infected with Plasmodium spp.MethodsOverall, there were collected 166 fecal samples and 25 blood samples from NHP, and 442 individuals of Anopheles spp. DNA extraction, nested PCR using mitochondrial (cox3 gene) and ribosomal (18S rDNA) primers, electrophoresis and sequencing were conducted in order to identify Plasmodium spp. from the samples.ResultsPlasmodium falciparum was detected in two fecal samples of Alouatta seniculus, while Plasmodium vivax/simium infected Ateles hybridus, Cebus versicolor and Alouatta seniculus. Co-infections with P. vivax/simium and Plasmodium malariae/brasilianum were found in three individuals. The highest prevalence from blood samples was found for Plasmodium malariae/brasilianum in two Alouatta seniculus while Plasmodium vivax/simium was most prevalent in fecal samples, infecting four individuals of Alouatta seniculus. Seven Anopheles species were identified in the study site: Anopheles (Anopheles) punctimacula, Anopheles (An.) malefactor, Anopheles (Nyssorhynchus) oswaldoi, Anopheles (Nys.) triannulatus, Anopheles (An.) neomaculipalpus, Anopheles (Nys.) braziliensis and Anopheles (Nys.) nuneztovari. Infection with P. vivax/simium was found in An. nuneztovari, An. neomaculipalpus, and An. triannulatus. Furthermore, An. oswaldoi and An. triannulatus were found infected with P. malariae/brasilianum. The effect of fragmentation and distance to the nearest town measured in five forests with different degrees of fragmentation was not statistically significant on the prevalence of Plasmodium in NHP, but forest fragmentation did have an effect on the Minimum Infection Rate (MIR) in Anopheles mosquitoes.ConclusionsThe presence of Plasmodium spp. in NHP and Anopheles spp. in fragmented forests in Colombia has important epidemiological implications in the human–NHP interface and the associated risk of malaria transmission.

Human gender determination based on the measurements of handprints that are devoid of dermatoglyphic features

To prove the possibility of gender determination from handprints without papillary ridge features by means of discriminant analysis of their dimensional characteristics, and to compare discriminant models with the results of visual sex classification and data of other authors. The handprints of 162 adult subjects (68 males and 94 females), were examined using metrics that are usually not measured on the human body, such as the length of the hand without the distal phalanx of the third finger, the length of the hand from the center of the palm, the width of the ulnar part of the palm, the diagonal width of the palm, and the length of the first beam. The table editor Excel 2003 and statistical software package SPSS 14.0 for Windows have been used to carry out the statistical processing of the material. We used a multidimensional discriminant analysis by Fisher's method in a step-by-step version. All the proposed measurements of the handprint meet the reliability requirements (rTEM5%; R>0.950). The accuracy of discriminant functions varies from 80 to 90.6%, which is noticeably higher compared to the visual definition (62.0-68.0%). Verification of the models (6 cases out of 8) proved the possibility of significant improvement of human gender determination when using the calculation method, compared with the visual method. The high data content of the additional planimetric parameters suggests the suitability of the gender determination models at different degrees of fragmentation of handprints. A necessary condition for the measurements on the handprint is the absence of any visible distortion of its proportions. The results of the gender analysis when measuring a handprint are comparable with the data obtained from skeletal material, from the hand itself and from its dermatoglyphic prints. this study may prove useful in determining human gender through measurements of handprints that are devoid of dermatoglyphic features during a forensic investigation.

Investigation of the structure of debris beds formed from fuel rods fragmentation

This paper is a study of debris beds that can form in the core of a nuclear power plant under severe accident conditions. Such beds are formed of fragments of pellets and cladding remnants, as observed in the TMI-2 core. Many important issues are related with the morphology of those debris beds: are they coolable in case of water injection and how does molten corium progress through them if they are not coolable? The answers to those questions depend on the structure of the debris bed: porosity, number and arrangement of particles. In order to obtain relevant information, a numerical simulation of the formation of the debris bed is proposed. It relies on a granular approach of the type called “Contact Dynamics” to simulate the collapse of debris and their accumulation. Two different schemes of fuel pellet fragmentation are considered and simulations for different degrees of fragmentation of the pellets are performed. The results show that the number of axial cracks on fuel pellets strongly influences the final porosity of the debris bed. Porosities vary between 31% (less coolable cases) and 45% (similar to TMI-2 observations), with a most probable configuration around 41%. The specific surface of the bed is also evaluated. In the last part, a simple model is used to estimate the impact of the variation in geometry of the numeric debris beds on their flow properties. We show that the permeability and passability can vary respectively with a range of 30% and 15% depending on the number of fragment per pellet. The other benefits of the approach are finally discussed. Among them, the possibility to print 3D samples from the calculated images of debris beds appears as a promising perspective to perform experiments with realistic debris beds.

Effect of Zn, Mg, Cu, Zr on Microstructure and Properties of Laser Welding Aluminium Alloy

A series of Al-6.3Zn-2.3Mg-2.3Cu-0.15Zr alloys with different reduce of Zn, Mg, Cu and Zr were prepared by ingot-metallurgy processing. The metallurgical structure and mechanical properties were investigated by optical microscope, scanning electron microscopy and other equipment. The results indicated that the ingot’s microstructures of the four alloys contain the phrases of η (MgZn2) and θ (Al2Cu), which mostly distribute at the grain boundaries in a shape of continuous network. After extrusion processing, the grain of laser welding aluminium alloy was elongated along the extrusion direction, therefore forming fibrous structures, and meanwhile the second phase particles with different degrees of fragmentation were arranged along the extrusion direction since the microstructure of extruded bars was inherited by the as-cast structure. Zr could significantly inhibit recrystallization of alloy; the recrystallization of the alloy with lower Zr was more obvious. As the content of Zr reduced, the tensile strength of alloy decreased, but the electrical conductivity and hardness increased. When the content of Cu was lower, the hardness were decreased.

Tephra ring interpretation in light of evolving maar–diatreme concepts: Stracciacappa maar (central Italy)

Maar–diatreme volcanoes in their simplest form are thought to result primarily from discrete, subsurface phreatomagmatic explosions. Tephra ring deposits around maar craters are commonly interpreted in terms of a framework wherein explosions begin at shallow levels and migrate downward, ejecting progressively deeper-seated lithic clasts that contribute to the tephra rings. Additionally, variations in grain size of the deposits are sometimes inferred to record different degrees of fragmentation, which are in turn related to variations in magma–water ratios at the explosion sites. Recent detailed studies of diatremes and of maar tephra rings suggest a different conceptual model wherein explosions can happen at various vertical and lateral locations within a diatreme during its eruptive lifetime, rather than being limited to simple downward migration. Experiments, numerical modeling, and field data indicate that most explosions deeper than about 200–250m will not vent to the surface, but instead contribute to mixing within the diatremes. Arrival of deep-seated lithics at the surface is related to this mixing process. Experiments also indicate that explosion phenomena can result in a range of emplacement mechanisms and grain sizes in tephra rings, even in the absence of variations in explosion mechanisms (fragmentation efficiency). Here we document the tephra ring of Stracciacappa maar (central Italy), and interpret its eruption and emplacement history in terms of evolving conceptual models along with a comparison to more traditional interpretations. Because most elements of both conceptual models are viable, the work points to an important need to develop criteria to distinguish between the various inferred mechanisms.