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Sample records for semiarid region northeastern

  1. Potential oilseed crops from the semiarid region of northeastern Brazil.

    PubMed

    Pinho, R S; Oliveira, A F M; Silva, S I

    2009-12-01

    The caatinga semi-arid ecosystem of northeastern Brazil is characterized by a dry, spiny and predominantly deciduous shrub/forest vegetation, and many species there are potential sources of renewable resources for the oleochemical industry. The present research determined the oil content and fatty acid profiles of seeds from eight caatinga species. Seed oils were extracted in a Soxhlet system, and their fatty acid content identified by GC-MS. Oil content varied between 20.2% in Tabebuia impetiginosa (Mart.) Standl. (Bignoniaceae) and 46.4% in Barnebya harleyi (W.R. Anderson & B. Gates) Malpighiaceae. Anemopaegma laeve DC. (Bignoniaceae) had the highest oleic acid content (63.4%), while high levels of linoleic acid were found in Banisteriopsis pubipetala (Juss.) Cuatrec. (42.8%) and B. harleyi (31.9%) (both Malpighiaceae). Palmitic acid was the major fatty acid (50%) in Hippocratea volubilis (L.) (Celastraceae). High levels of linoleic and linolenic acids were found in Croton adamantinus Mull. Arg. (Euphorbiaceae), averaging 44.2% and 45.2% respectively. Gadoleic acid in was the most abundant fatty acid in the oil produced by Serjania lethalis A. St. Hill. (Sapindaceae), averaging 69.6%. B. pubipetala, B. harleyi, C. adamantinus, and H. volubilis were identified as promising species for cultivation.

  2. New species and records of Anacroneuria (Plecoptera: Perlidae) from the northeastern semi-arid region of Brazil.

    PubMed

    Duarte, Tácio; Lecci, Lucas Silveira

    2016-02-11

    The genus Anacroneuria is widely distributed in the Neotropical Region. There are about 80 species listed from Brazil, five of which are recorded from the northeastern semi-arid region of Brazil, an area characterized by irregular and low precipitation. Examination of adult Anacroneuria material from this including areas of Caatinga desert vegetation and Atlantic forest revealed two new species records, A. debilis (Pictet) and A. terere Righi-Cavallaro & Lecci. Additionally, two new species, A. calori n. sp. and A. singela n. sp., are described from this material. These new records and new species reflect a major effort to document the biodiversity of the aquatic insects of the northeastern semi-arid region of Brazil by the Research Program in Semi-arid Biodiversity.

  3. Traditional uses of medicinal animals in the semi-arid region of northeastern Brazil

    PubMed Central

    2012-01-01

    The present work presents an inventory of the traditional medicinal uses of animals in the municipality of Bom Sucesso in Paraíba State (PB) in the semiarid northeastern region of Brazil. Information was obtained through the use of semi-structured interviews with 50 people who use zootherapeutic products. A total of 25 animal species used for medicinal purposes were identified (18 vertebrates and seven invertebrates) distributed among five taxonomic categories; the groups with the largest numbers of citations were: mammals (8 citations), insects (7), and reptiles (5). The most cited animal species were: Tubinambis merianae “teju” lizards (44 citations); Apis mellifera Italian honeybees (318 citations); Gallus gallus chickens (31 citations); Ovis aries sheep (31 citations); Crotalus durissus rattlesnakes (14 citations); Boa constrictor (12 citations); and Bos taurus cattle (12 citations). A significant number of illnesses and conditions treated with animal-based medicines were cited, and the category with the greatest number of citations was “problems affecting the respiratory system”. Our results suggest that the use of zootherapeutics in the region is persistent, and that knowledge about these curative practices is an integral part of the regional culture. As such, studies concerning the uses of zootherapeutics are important windows to understanding human/environmental/cultural interactions and a pathway to conciliating regional cultures with efforts to conserve the native fauna. PMID:23050756

  4. Ehrlichia canis in dogs in a semiarid region of Northeastern Brazil: serology, molecular detection and associated factors.

    PubMed

    Tanikawa, A; Labruna, M B; Costa, A; Aguiar, D M; Justiniano, S V; Mendes, R S; Melo, A L T; Alves, C J; Azevedo, S S

    2013-06-01

    This study investigated infection by Ehrlichia spp. agents by PCR, immunofluorescence assay test (IFAT), and by Giemsa-stained blood smears in 108 dogs from a semiarid region of the state of Paraíba, Northeastern Brazil. Seventy-five (69.4%) of the 108 dogs were found to be seropositive to Ehrlichia canis, while only four dogs (3.7%) were positive in real-time PCR for E. canis. In six dogs (5.6%) E. canis-like morulae were observed in monocytes. Animals that stayed in environment whose floor was dried dirt, and dogs whose owners reported low frequency of cleaning the dog environment had higher (P<0.05) PCR positivity for E. canis. Increasing seropositivity was found in older dogs (P=0.012). This study provides the first molecular detection of E. canis in the semiarid region of Northeastern Brazil.

  5. Students’ attitudes toward and knowledge about snakes in the semiarid region of Northeastern Brazil

    PubMed Central

    2014-01-01

    Background Humans in various cultures have feared snakes, provoking an aversion and persecution that hinders conservation efforts for these reptiles. Such fact suggests that conservation strategies for snakes should consider the interactions and perceptions of the local population towards these animals. The aim of this study was to investigate students' perception of snakes and if attitudes and knowledge may differ according to gender and local residence (urban or rural). Methods Data was collected in the second half of 2012 and consisted of questionnaires applied to 108 students in the Basic Education School in the municipality of Sumé, located in the semiarid region of Northeastern Brazil. Results The male respondents recognized more species than female did. Part of the students affirmed to have a fear of snakes, especially women. Nearly half of respondents (49%) showed negative behaviour towards these animals, reflecting the influence of potential risk and myths associated with snakes, and supported by a limited knowledge about these animals and their ecological and utilitarian role. We find that the rural students recognized significantly more species than the urban students. Conclusions Our results point to the need for educational interventions in order to increase knowledge about the positive aspects associated with snakes, seeking to minimize the influence of myths and beliefs that contribute to a strong aversion to snakes by the locals. Conservation strategies should therefore engage students but also teachers, who are key individuals in the process. PMID:24673877

  6. Animal-Based Remedies as Complementary Medicines in the Semi-Arid Region of Northeastern Brazil

    PubMed Central

    Alves, Rômulo R. N.; Barbosa, José A. A.; Santos, Silene L. D. X.; Souto, Wedson M. S.; Barboza, Raynner R. D.

    2011-01-01

    Animals (and their derived products) are essential ingredients in the preparation of many traditional remedies. Despite its prevalence in traditional medical practices worldwide, research on medicinal animals has often been neglected in comparison to medicinal plant research. This work documents the medicinal animals used by a rural community in the semi-arid region, inserted in Caatinga Biome, where 66 respondents provided information on animal species used as medicine, body parts used to prepare the remedies and illnesses to which the remedies were prescribed. We calculated the informant consensus factor to determine the consensus over which species are effective for particular ailments, as well as the species use value to determine the extent of utilization of each species. We recorded the use of 51 animal species as medicines, whose products were recommended for the treatment of 68 illnesses. The informant consensus in the use of many specific remedies is fairly high, giving an additional validity to this folk medicine. Eight species not previously reported as having medicinal use were recorded. The local medicinal fauna is largely based on wild animals, including some endangered species. Given a high proportion of medicinal animals observed in the study area, it is logical to conclude that any conservation strategy should include access to modern health care. PMID:19729490

  7. Animals to heal animals: ethnoveterinary practices in semiarid region, Northeastern Brazil

    PubMed Central

    2009-01-01

    Background Animal-based remedies constitute an integral part of Traditional Medicine and this is true in Brazil as well both in rural and urban areas of the country. Due to its long history, zootherapy has in fact become an integral part of folk medicine in the country. The use of these natural resources for medical purposes, however, is not restricted to human diseases treatment, being also widely used for the treatment of animal illnesses. Ethnoveterinary is a science that involves the popular practical knowledge used to treat and prevent animal diseases. This study documents ethnoveterinary practices in one local semi-arid region in Northeast Brazil and discusses the findings in the surveyed area. Methods Information was obtained through the use of semi-structured questionnaires. A total of 20 respondents (09 men and 11 women) provided information on animal species and body parts used as medicine, information concerning the illnesses to which the remedies were prescribed were also obtained. Results and conclusion Eleven animal species were used in the treatment of 11 diseases in the surveyed area. The species inventoried comprise 3 taxonomic categories: mammals (05), reptiles (04) and birds (02). The obtained results proves that the use of animals or their derived products as therapeutic resources to the treatment of animal diseases represent a common practice and is culturally important in the studied area. It is evident that the popular knowledge about the ethnoveterinary practices is, frequently, passed through generations. We also noticed that, besides the cultural aspects, the socio-economic context permeates the use of zootherapics, since these practices constitute an alternative to the medicines acquired in veterinarian pharmacies, which have a high cost. PMID:19941663

  8. Ectoparasite Infestations and Canine Infection by Rickettsiae and Ehrlichiae in a Semi-Arid Region of Northeastern Brazil

    PubMed Central

    Araes-Santos, Ana Isabel; Moraes-Filho, Jonas; Peixoto, Renata M.; Spolidorio, Mariana G.; Azevedo, Sérgio S.; Costa, Mateus M.; Labruna, Marcelo B.

    2015-01-01

    Abstract This study investigated the prevalence of Rickettsia spp. and Ehrlichia canis infection in dogs and their ectoparasites from rural and urban areas of two municipalities, Petrolina and Juazeiro, within a semiarid region (Caatinga biome) of northeastern Brazil, by immunofluorescence assay (IFA) and polymerase chain reaction (PCR). Overall, 12.1% (61/504) and 23.0% (116/504) of canine plasma samples had antibodies reactive to Rickettsia spp. and E. canis. E. canis DNA was detected by PCR in 8.3% (42/504) of canine blood samples, whereas no blood sample was positive for Rickettsia spp. The infection by E. canis was determined by PCR in 4.9% (14/285) Rhipicephalus sanguineus sensu lato (s.l.) ticks and by Rickettsia felis in 1.1% (3/285) and 40.6% (74/182) ticks and fleas, respectively. Multivariate regression analyses revealed that canine seropositivity to Rickettsia spp. was associated statistically with the variables “to reside in Petrolina” and “presence of ectoparasites.” Our results indicate that canine infection by E. canis might be endemic in the Caatinga biome as it is in other Brazilian biomes. Although no previous serosurvey for Rickettsia spp. has been conducted on dogs from the Caatinga biome, our values are much lower than the ones reported for rural dogs from other Brazilian biomes. These differences are likely related to the semiarid climate of the aatinga biome, which minimizes the exposure of rural dogs to Amblyomma spp. ticks, the most common vectors of Rickettsia spp. in Brazil. Considering that dogs are excellent sentinels for human exposure to Rickettsia spp., we can infer that the risks of human acquiring tick-borne rickettsiosis in the Caatinga region of the present study are low. The rickettsial infection rates in fleas and ticks were not related to canine seropositivity; i.e., areas with higher Rickettsia infection rates in fleas had the lowest canine seroreactivity to Rickettsia spp. PMID:26565771

  9. Hunting strategies used in the semi-arid region of northeastern Brazil.

    PubMed

    Alves, Rômulo R N; Mendonça, Lívia E T; Confessor, Maine V A; Vieira, Washington L S; Lopez, Luiz C S

    2009-04-22

    Hunting for wild animals is stimulated by the many different human uses of faunal resources, and these animals constitute important subsistence items in local communities in the Caatinga region. In order to gain access to these resources, hunters have developed a series of techniques and strategies that are described in the present work. The principal hunting techniques encountered were: waiting, especially directed towards hunting diurnal birds; calling ("arremedo"), a technique in which the hunters imitate the animal's call to attract it to close range; hunting with dogs, a technique mostly used for capturing mammals; tracking, a technique used by only a few hunters who can recognize and follow animal tracks; and "facheado", in which the hunters go out at night with lanterns to catch birds in their nests. Additionally, many animal species are captured using mechanical traps. The types of traps used by the interviewees were: dead-fall traps ("quixó"), iron-jaw snap traps ("arataca"), wooden cages with bait ("arapuca"), iron-cage traps ("gaiola'), "visgo", multi-compartment bird cages ("alçapão"), buried ground traps with pivoted tops ("fojo"), and nooses and cages for carnivorous. The choice of which technique to use depends on the habits of the species being hunted, indicating that the hunters possess a wide knowledge of the biology of these animals. From a conservation perspective, active hunting techniques (waiting, imitation, hunting with dogs, and "facheado") have the greatest impact on the local fauna. The use of firearm and dogs brought greater efficiency to hunting activities. Additional studies concerning these hunting activities will be useful to contribute to proposals for management plans regulating hunting in the region - with the objective of attaining sustainable use of faunal resources of great importance to the local human communities.

  10. Hunting strategies used in the semi-arid region of northeastern Brazil

    PubMed Central

    Alves, Rômulo RN; Mendonça, Lívia ET; Confessor, Maine VA; Vieira, Washington LS; Lopez, Luiz CS

    2009-01-01

    Hunting for wild animals is stimulated by the many different human uses of faunal resources, and these animals constitute important subsistence items in local communities in the Caatinga region. In order to gain access to these resources, hunters have developed a series of techniques and strategies that are described in the present work. The principal hunting techniques encountered were: waiting, especially directed towards hunting diurnal birds; calling ("arremedo"), a technique in which the hunters imitate the animal's call to attract it to close range; hunting with dogs, a technique mostly used for capturing mammals; tracking, a technique used by only a few hunters who can recognize and follow animal tracks; and "facheado", in which the hunters go out at night with lanterns to catch birds in their nests. Additionally, many animal species are captured using mechanical traps. The types of traps used by the interviewees were: dead-fall traps ("quixó"), iron-jaw snap traps ("arataca"), wooden cages with bait ("arapuca"), iron-cage traps ("gaiola'), "visgo", multi-compartment bird cages ("alçapão"), buried ground traps with pivoted tops ("fojo"), and nooses and cages for carnivorous. The choice of which technique to use depends on the habits of the species being hunted, indicating that the hunters possess a wide knowledge of the biology of these animals. From a conservation perspective, active hunting techniques (waiting, imitation, hunting with dogs, and "facheado") have the greatest impact on the local fauna. The use of firearm and dogs brought greater efficiency to hunting activities. Additional studies concerning these hunting activities will be useful to contribute to proposals for management plans regulating hunting in the region – with the objective of attaining sustainable use of faunal resources of great importance to the local human communities. PMID:19386121

  11. Medicinal plants popularly used in the Xingó region – a semi-arid location in Northeastern Brazil

    PubMed Central

    Almeida, Cecília de Fátima CBR; de Amorim, Elba Lúcia Cavalcanti; de Albuquerque, Ulysses Paulino; Maia, Maria Bernadete S

    2006-01-01

    The aim of this study was to identify plant species among the diverse flora of the caatinga ecosystem that are used therapeutically. Research was undertaken in the municipalities of Piranhas and Delmiro Gouveia, in the Xingó region (state of Alagoas, NE Brazil). In order to identify the medicinal plants used in this region, semi-structured questionnaires were applied. The species cited were collected and sent to the Xingó Herbarium for taxonomic analysis. The relative importance (RI) of each species cited was calculated to verify their cultural importance. The therapeutic indications attributed to the species were classified under 16 body systems. A total of 187 medicinal species were cited, from 64 families and 128 genera. The main indications for medicinal plant use were against common colds, bronchitis, cardiovascular problems, kidney problems, inflammations in general, and as tranquilizers. Approximately 16% (30 plant species) were versatile in relation to their use, with an Relative Importance value over 1, having been indicated for up to nine body systems. The body systems that stood out the most were: the respiratory system, the gastrointestinal system, and infectious diseases. Most cited plant parts used for medicinal purposes were flowers, leaves, and inner stem bark. PMID:16556305

  12. Physical characteristics and discharges of suspended particulate matter at the continent-ocean interface in an estuary located in a semiarid region in northeastern Brazil

    NASA Astrophysics Data System (ADS)

    Dias, Francisco Jose da Silva; Castro, Belmiro Mendes; Lacerda, Luiz Drude; Miranda, Luiz Brunner; Marins, Rozane Valente

    2016-10-01

    This study reports the hydrodynamics of the transport of suspended particulate matter (SPM) in the Jaguaribe River estuary, which receives the runoff from the largest drainage basin in the state of Ceará, Brazil. The estuary is located in the semiarid region of Brazil, where rainfall occurs primarily between January and May and results in water flow rates exceeding 3000 m3s-1. The drainage basin contains more than 4000 dams, which, during the dry season, block most of the flow of freshwater and sediment. The net balance and transport of sediments were calculated for the wet and dry seasons considering a tidal cycle of 13 h at the interfaces between the upper and middle estuary and between the middle and lower estuary. The Jaguaribe River estuary is classified as partially mixed with weak vertical stratification and a tendency toward being well mixed. The SPM transported during the rainy season originates in the drainage basin due to high river inflow, whereas during the dry season, resuspension and hydraulic fills generated by tides causes the accumulation of SPM in the middle estuary, forming a zone of maximum turbidity. The transport of salt in the estuary was predominantly caused by gravity flow and tidal propagation.

  13. Ticks and tick-borne viruses from livestock hosts in arid and semiarid regions of the eastern and northeastern parts of Kenya.

    PubMed

    Lutomiah, Joel; Musila, Lillian; Makio, Albina; Ochieng, Caroline; Koka, Hellen; Chepkorir, Edith; Mutisya, James; Mulwa, Francis; Khamadi, Samoel; Miller, Barry R; Bast, Joshua; Schnabel, David; Wurapa, Eyako K; Sang, Rosemary

    2014-01-01

    Biodiversity and relative abundance of ticks and associated arboviruses in Garissa (northeastern) and Isiolo (eastern) provinces of Kenya were evaluated. Ticks were collected from livestock, identified to species, pooled, and processed for virus isolation. In Garissa, Rhipicephalus pulchellus Gerstacker (57.8%) and Hyalomma truncatum Koch (27.8%) were the most abundant species sampled, whereas R. pulchellus (80.4%) and Amblyomma gemma Donitz (9.6%) were the most abundant in Isiolo. Forty-four virus isolates, comprising Dugbe virus (DUGV; n = 22) and Kupe virus (n = 10; Bunyaviridae: Nirovirus), Dhori virus (DHOV; n = 10; Orthomyxoviridae: Thogotovirus),and Ngari virus (NRIV; n = 2; Bunyaviridae: Orthobunyavirus), were recovered mostly from R. pulchellus sampled in Isiolo. DUGV was mostly recovered from R. pulchellus from sheep and cattle, and DHOV from R. pulchellus from sheep. All Kupe virus isolates were from Isiolo ticks, including R. pulchellus from all the livestock, A. gemma and Amblyomma variegatum F. from cattle, and H. truncatum from goat. NRIV was obtained from R. pulchellus and A. gemma sampled from cattle in Isiolo and Garissa, respectively, while all DHOV and most DUGV (n = 12) were from R. pulchellus sampled from cattle in Garissa. DUGV was also recovered from H. truncatum and Amblyomma hebraeum Koch from cattle and from Rhipicephalus annulatus Say from camel. This surveillance study has demonstrated the circulation of select tick-borne viruses in parts of eastern and northeastern provinces of Kenya, some of which are of public health importance. The isolation of NRIV from ticks is particularly significant because it is usually known to be a mosquito-borne virus affecting humans.

  14. Amanita lippiae: a new species from the semi-arid caatinga region of Brazil.

    PubMed

    Wartchow, Felipe; Tulloss, Rodham E; Cavalcanti, Maria A Q

    2009-01-01

    Amanita lippiae is described as a new species from a semi-arid (caatinga) region of northeastern Brazil. It possesses clampless basidia and elongate to nearly cylindrical inamyloid basidiospores, bears irregular remains of universal veil on the stipe bulb and is a gemmatoid species assignable to Amanita sect. Amanita.

  15. Mimosa tenuiflora as a Cause of Malformations in Ruminants in the Northeastern Brazilian Semiarid Rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Craniofacial anomalies, eye malformations, and permanent flexures of the forelimbs are common malformations seen in ruminants grazing semiarid rangelands of Northeastern Brazil. To investigate the cause of these malformations, we fed 2 suspected plants, Mimosa tenuiflora or Prosopis juliflora, to gr...

  16. Birds and people in semiarid northeastern Brazil: symbolic and medicinal relationships

    PubMed Central

    2013-01-01

    Abstract Background At least 511 species of birds occur in the semiarid region of northeastern Brazil and many of them interact with human populations in a number of different ways, including their use in zootherapeutics and their links with local beliefs. Objective The present work examined these types of birds/human interactions (use in zootherapeutics and their links with local beliefs) in the semiarid region of Rio Grande do Norte State in northeastern Brazil. Methods Information was obtained through semi-structured interviews with 120 local residents. Results A total of 16 wild bird species distributed among 11 families were found to interact directly with humans, with Columbidae being the best represented family. Seven species were identified in the medicinal category, five were related to symbolic aspects, while four species were identified as being related to both categories (medicinal and symbolic). Conclusion The accumulated folk knowledge, beliefs, and practices involving the avifauna in the semiarid region of Brazil, whether symbolic or medicinal, demonstrated the cultural importance of this vertebrate group to local human populations and revealed a belief system intrinsically related to cynegetic practices in the region. Portuguese abstract Introdução No semiárido do Brasil ocorrem 511 espécies de aves, algumas das quais interagem frequentemente com as populações humanas locais de diferentes formas, incluindo o uso como zooterápico e a inserção em crenças. Objetivo Esta pesquisa registrou as aves diretamente associadas a essas formas de interação (o uso como zooterápico e a inserção em crenças) na região semiárida do Estado do Rio Grande do Norte, Nordeste do Brasil. Métodos As informações foram obtidas através de entrevistas semiestruturadas aplicadas a 120 moradores locais. Resultados Foram registradas 16 espécies de aves silvestres distribuídas em 11 famílias, sendo Columbidae a que apresentou o maior número de

  17. Nutritional status of children and adolescents from a town in the semiarid Northeastern Brazil☆

    PubMed Central

    Ramires, Elyssia Karine Nunes Mendonça; de Menezes, Risia Cristina Egito; Oliveira, Juliana Souza; Oliveira, Maria Alice Araújo; Temoteo, Tatiane Leocádio; Longo-Silva, Giovana; Leal, Vanessa Sá; Costa, Emília Chagas; Asakura, Leiko

    2014-01-01

    Objective: To evaluate the nutritional status of schoolchildren, resident in a semiarid region in the Northeastern Brazil. Methods: This is a cross-sectional study, involving 860 children and adolescents aged from 5-19 years-old, enrolled in three public schools in the county. The selection of schools was non-probabilistic type and unintentional. The initial population, which integrated the database, was composed by 1,035 children and teenagers, and 175 students (16.9%) were excluded because of inconsistency in the anthropometric data, resulting in a sample of 860 students. The following outcomes were considered: stunting (malnutrition), overweight and obesity (overweight), being the height/age and body mass index/age (BMI/Age), indices respectively used. Children and adolescents with height <-2 standard deviations and overweight and obese weight z score ≥1 were considered stunted. The statistical analysis was descriptive. Results: The prevalence of stunting and overweight/obesity was 9.1% and 24.0%, respectively. Overweight and stunting were higher in adolescents aged 15 and over, compared to other age groups analyzed. In relation to gender, malnutrition presented itself in a similar way, but overweight was more frequent among females. Conclusions: The results revealed that excess weight, here represented by the sum of overweight and obesity, was more prevalent than stunting (malnutrition), highlighting the urgent need for attention to this problem in order to design interventions capable of contributing to the improvement of schoolchildren nutritional status. PMID:25479850

  18. Physical attributes of Ultisol of Brazil's northeastern semiarid under organic farming of wine grapes.

    PubMed

    Feitosa, Jardenia R; Mendes, Alessandra M S; Olszevski, Nelci; Cunha, Tony J F; Cortez, Jorge W; Giongo, Vanderlise

    2015-03-01

    The purpose of this study was to evaluate the effects of organic farming of wine grapes under physical and chemical characteristics of Ultisol Brazil's northeastern semiarid region. The samples of soil were collected from the row and interrow of the farming and from the fallow area, at the depths of 0.0-0.10, 0.10-0.20, 0.20-0.30 and 0.30-0.60 m. The samples were collected at six and twelve months after the culture implementation to evaluate the state of aggregation, bulk density and total soil porosity, flocculation index and organic matter contents, calcium, magnesium, and sodium. The results were submitted to statistical analysis. The adoption of organic farming contributed to the soil aggregation process. The bulk density and total soil porosity did not differ significantly between the evaluations, but were within the critical limits for sandy soils. The index flocculation did not have a great influence on the aggregates formation, being this process influenced by organic matter. The period of one year was considered short to obtain conclusive results in improving the soil quality by organic farming, since there are difficulties in tropical soils in promoting significant increases in organic matter content in short time.

  19. Necrophagous beetles associated with carcasses in a semi-arid environment in northeastern Brazil: implications for forensic entomology.

    PubMed

    Mayer, Ana C G; Vasconcelos, Simão D

    2013-03-10

    Data on the ecology and bionomics of necrophagous beetles are scarce in tropical countries despite their relevance in forensic investigations. We performed a survey on the diversity and temporal pattern of colonization of beetles on pig carcasses in a fragment of dry forest in northeastern Brazil. We collected 1550 adults of diverse feeding habits from 12 families, of which 96% had necrophagous and/or copro-necrophagous habits and belonged to four families: Dermestidae, Scarabaeidae, Cleridae and Trogidae. Three species, Dermestes maculatus, Necrobia rufipes and Omorgus suberosus are reported for the first time with an expanded geographical distribution that includes the semi-arid region in Brazil. Adult beetles were collected as early as 24h after death. One endemic species, Deltochilum verruciferum, stood out in terms of numerical dominance and temporal occurrence during different stages of decomposition. Its intimate association with carrion emphasizes their potential role in forensic entomology in the region.

  20. Quaternary ecological and geomorphic changes associated with rainfall events in presently semi-arid northeastern Brazil

    NASA Astrophysics Data System (ADS)

    Auler, Augusto S.; Wang, Xianfeng; Edwards, R. Lawrence; Cheng, Hai; Cristalli, Patrícia S.; Smart, Peter L.; Richards, David A.

    2004-10-01

    Several geomorphic features and palaeobiotic remains in now semi-arid northeastern Brazil indicate major palaeoenvironmental changes during past periods of increased rainfall. 230Th mass spectrometric ages of speleothems and travertines have allowed the determination of the timing and duration of wetter than present conditions. The data demonstrate that wet events have occurred throughout much of the Pleistocene, present dry conditions having been established at the end of the Younger Dryas. A markedly different fauna comprising megafaunal elements not adapted to the present low arboreal scrubland caatinga vegetation existed in the area. Palaeobotanical remains embedded in travertine indicate forested vegetation at these wetter intervals, suggesting that the caatinga was then replaced or mixed with a semi-deciduous forest. Due to the abundance of travertine sites containing fossil botanical remains in northeastern Brazil, it is believed that forest expansion occurred over large areas of the now semi-arid zone, showing that the long hypothesised forested links between biodiversity-rich Amazon and Atlantic rainforests may indeed have existed during these moister phases. Copyright

  1. Mimosa tenuiflora as a cause of malformations in ruminants in the northeastern Brazilian semiarid rangelands.

    PubMed

    Pimentel, L A; Correa, F Riet; Gardner, D; Panter, K E; Dantas, A F M; Medeiros, R M T; Mota, R A; Araújo, J A S

    2007-11-01

    Craniofacial anomalies, eye malformations, and permanent flexures of the forelimbs are common malformations seen in ruminants grazing semiarid rangelands of Northeastern Brazil. To investigate the cause of these malformations, we fed 2 suspected plants, Mimosa tenuiflora or Prosopis juliflora, to groups of 4 pregnant goats each. Fresh green M. tenuiflora was collected daily and fed ad libitum to 4 goats in group 1 throughout pregnancy. This treatment group also received a supplemental feed concentrate equivalent to 1% body weight. Four goats in group 2 received a ration with 70% of P. juliflora pods and 30% hay throughout pregnancy. Four control goats were fed supplemental feed concentrate (1% body weight) and hay ad libitum throughout pregnancy. Goats treated with P. juliflora pods and the control goats delivered 9 normal kids. The four goats that were fed M. tenuiflora during pregnancy delivered 4 kids, 3 of which had abnormalities similar to those observed in field cases, including cleft lip, unilateral corneal opacity, ocular bilateral dermoids, buphthalmos with a cloudy brownish appearance of the anterior chamber due to an iridal cyst, and segmental stenosis of the colon. Malformations induced experimentally by M. tenuiflora were similar to those observed in field cases, suggesting that M. tenuiflora is a cause of the field cases observed in the Brazilian semiarid rangelands.

  2. Uses of tree legumes in semi-arid regions

    SciTech Connect

    Felker, P.

    1980-01-01

    Uses of tree legumes in semi-arid and arid regions are reviewed. This review is divided into sections according to the following general use categories: fuels; human food; livestock food; to increase yields of crops grown beneath their canopies;and control of desertification. (MHR)

  3. Ecohydrological control of deep drainage in arid and semiarid regions

    USGS Publications Warehouse

    Seyfried, M.S.; Schwinning, S.; Walvoord, M.A.; Pockman, W. T.; Newman, B.D.; Jackson, R.B.; Phillips, F.M.

    2005-01-01

    The amount and spatial distribution of deep drainage (downward movement of water across the bottom of the root zone) and groundwater recharge affect the quantity and quality of increasingly limited groundwater in arid and semiarid regions. We synthesize research from the fields of ecology and hydrology to address the issue of deep drainage in arid and semiarid regions. We start with a recently developed hydrological model that accurately simulates soil water potential and geochemical profiles measured in thick (>50 m), unconsolidated vadose zones. Model results indicate that, since the climate change that marked the onset of the Holocene period 10 000-15 000 years ago, there has been no deep drainage in vegetated interdrainage areas and that continuous, relatively low (<-1 MPa) soil water potentials have been maintained at depths of 2-3 m. A conceptual model consistent with these results proposes that the native, xeric-shrub-dominated, plant communities that gained dominance during the Holocene generated and maintained these conditions. We present three lines of ecological evidence that support the conceptual model. First, xeric shrubs have sufficiently deep rooting systems with low extraction limits to generate the modeled conditions. Second, the characteristic deep-rooted soil-plant systems store sufficient water to effectively buffer deep soil from climatic fluctuations in these dry environments, allowing stable conditions to persist for long periods of time. And third, adaptations resulting in deep, low-extraction-limit rooting systems confer significant advantages to xeric shrubs in arid and semiarid environments. We then consider conditions in arid and semiarid regions in which the conceptual model may not apply, leading to the expectation that portions of many arid and semiarid watersheds supply some deep drainage. Further ecohydrologic research is required to elucidate critical climatic and edaphic thresholds, evaluate the role of important physiological

  4. Estimate of shallow groundwater recharge in the Hadejia-Nguru Wetlands, semi-arid northeastern Nigeria

    NASA Astrophysics Data System (ADS)

    Goes, B. J. M.

    1999-06-01

    The Hadejia-Nguru Wetlands are annually inundated flood plains in semi-arid northeastern Nigeria. The area has a unique ecosystem that forms a natural barrier against the encroachment of the Sahara desert. Both the rich wetland vegetation and local farmers using shallow tube wells depend on a groundwater mound (with a water table less than 6 m below the surface) that is present in the unconfined aquifer under the flood-plain area. Using well records (1991-97) and a hydrogeologic profile based on piezometers that were monitored for two years, it is shown that recharge through the annually inundated flood plains is the source of the groundwater mound. Maintenance of the groundwater-recharge function of the flood plains depends on wet-season releases from two large upstream dams. On the basis of a water-budget method, the mean (1991-97) wet-season unconfined groundwater recharge in the flood-plain area between Hadejia and Nguru and in the immediate vicinity (1250 km2) is estimated to be 132 mm (range, 73-197 mm). Outflow from the unconfined flood-plain aquifer to the unconfined upland aquifer is approximately 10% of the wet-season flood-plain recharge. The unconfined groundwater outflow from the flood-plain area can provide a significant contribution to the present-day rural water supply in the surrounding uplands, but it does not offer much potential for additional groundwater abstraction. In addition to outflow to the upland aquifer (˜14 mm), the distribution of the annually recharged water volume of the shallow flood-plain aquifer is (1) domestic uses (3 mm), (2) small-scale irrigation (˜15 mm), and (3) evapotranspiration ( 1 100 mm). Along the hydrogeologic profile, the recharge in the upland (i.e., outflow from the unconfined flood-plain aquifer and possibly diffuse rain-fed recharge) is in balance with the water uses (i.e., domestic uses, groundwater outflow, and evapotranspiration). The absence of a seasonal water-level trend in the two piezometers in the

  5. Floristic similarity and dispersal syndromes in a rocky outcrop in semi-arid Northeastern Brazil.

    PubMed

    Costa, Elainne Cristina Silva; Lopes, Sérgio de Faria; Melo, José Iranildo Miranda de

    2015-09-01

    Floristic studies provide valuable information on species richness in a region, and are particularly important if these areas belong to less studied environments, such as rocky outcrops, that may increase our knowledge. An important aspect for species colonization includes the mechanisms of diaspores dispersal in each community; these are essential to understand its structure, dynamics, and the regeneration process, and constitute an important tool for conservation. We developed a floristic survey on a granite-gneiss outcrop with the objective to increase the knowledge on plant diversity, through a floristic similarity analysis and detection of dispersal syndromes of sampled species, in a semi-arid region of Brazil. The fieldwork included collection and observation of the botanical material in loco during a period of 12 months. A total of 161 species belonging to 127 genera and 50 families of angiosperms were recorded. Fabaceae, Asteraceae and Convolvulaceae were the most representative families in number of species. Allophylus quercifolius (Mart.) Radlk. (Capparaceae) and Lafoensia pacari A. St.-Hil. (Lythraceae) represented new records for the State of Paraiba. The autochoric syndrome was the most representative, with 51.5 % of the recorded species; the anemochory was the second most representative syndrome with 26.7 % of the species; and finally the zoochory, representing 22.3 % of the species. The floristic similarity dendrogram showed the formation of three well-defined groups, whose area with the highest value (J = 33.2) is located in a Caatinga region called Cariri Paraibano, while the lowest value observed (J = 5.2), occurred in a settled area in two geomorphological units, a crystalline complex and a plateau region. These results may be due to the varying topographic conditions and edaphic heterogeneity arising from the specific geological formation of the region. These results yet demonstrate that, in rocky outcrops, abiotic syndromes represent an

  6. Chemical Dependency Regional Needs Assessment: Northeastern Minnesota.

    ERIC Educational Resources Information Center

    Stone, Marylee

    The Minnesota Model of Chemical Dependency Treatment, which evolved from a combination of the grassroots Alcoholics Anonymous movement and the State Mental Health Services in the 1960s has made Minnesota an international leader in chemical dependency treatment efforts. Northeastern Minnesota has shared this reputation with the state. In spite of…

  7. Records of Bat Flies (Diptera: Nycteribiidae and Streblidae) in the Semi-Arid Caatinga in the State of Paraíba, Northeastern Brazil.

    PubMed

    Barbier, E; Prado-Neto, J G; Bernard, E

    2016-12-01

    One of the largest gaps in the knowledge of ectoparasitic flies of the families Nycteribiidae and Streblidae in Brazil is the northeastern region, where most states do not have any record. Here, we present the first records of those two bat fly families for the state of Paraíba. We recorded a total of 10 species of five genera parasitizing eight bat species of four families. Trichobius diphyllae Wenzel (Streblidae) was the most abundant species, found parasitizing Diphylla ecaudata (Phyllostomidae), and T. dugesioides dugesioides Wenzel, the second, found on Trachops cirrhosus (Phyllostomidae). Three species were recorded for the first time in northeastern Brazil and seven species are new for the semi-arid Caatinga. We collected T. galei Wenzel and T. pallidus (Curran) on Natalus macrourus (Natalidae) and Furipterus horrens (Furipteridae), respectively, two endangered bat species, and the species-specific relationship with their hosts points out to some degree of vulnerability. In addition, we present information on host-parasite relationship, and data that extend the known geographic distribution of some species.

  8. Regional geologic framework off northeastern United States

    USGS Publications Warehouse

    Schlee, J.; Behrendt, John C.; Grow, J.A.; Robb, James M.; Mattick, R.; Taylor, P.T.; Lawson, B.J.

    1976-01-01

    Six multichannel seismic-reflection profiles taken across the Atlantic continental margin Previous HitoffTop the northeastern United States show an excess of 14 km of presumed Mesozoic and younger sedimentary rocks in the Baltimore Canyon trough and 8 km in the Georges Bank basin. Beneath the continental rise, the sedimentary prism thickness exceeds 7 km south of New Jersey and Maryland, and it is 4.5 km thick south of Georges Bank. Stratigraphically, the continental slope--outer edge of the continental shelf is a transition zone of high-velocity sedimentary rock, probably carbonate, that covers deeply subsided basement. Acoustically, the sedimentary sequence beneath the shelf is divided into three units which are correlated speculatively with the Cenozoic, the Cretaceous, and the Jurassic-Triassic sections. These units thicken offshore, and some have increased seismic velocities farther offshore. The uppermost unit thickens from a fraction of a kilometer to slightly more than a kilometer in a seaward direction, and velocity values range from 1.7 to 2.2 km/sec. The middle unit thickens from a fraction of a kilometer to as much as 5 km (northern Baltimore Canyon trough), and seismic velocity ranges from 2.2 to 5.4 km/sec. The lowest unit thickens to a maximum of 9 km (northern Baltimore Canyon), and velocities span the 3.9 to 5.9-km/sec interval. The spatial separation of magnetic and gravity anomalies on line 2 (New Jersey) suggests that in the Baltimore Canyon region the magnetic-slope anomaly is due to edge effects and that the previously reported free-air and isostatic gravity anomalies over the outer shelf may be due in part to a lateral increase in sediment density (velocity) near the shelf edge. The East Coast magnetic anomaly and the free-air gravity high both coincide over the outer shelf edge on line 1 (Georges Bank) but are offset by 20 km from the ridge on the reflection profile. Because the magnetic-slope-anomaly wavelength is nearly 50 km across, a

  9. Karyotype Patterns of Hypsolebias antenori (Cyprinodontiformes: Rivulidae): An Endangered Killifish of the Semiarid Region of Brazil

    PubMed Central

    do Nascimento, Wallace Silva; Bezerra, Juliana Galvão; Lima-Filho, Paulo Augusto; Yamamoto, Maria Emília; Molina, Wagner Franco

    2014-01-01

    Annual fish which belong to the order Cyprinodontiformes constitute an excellent model for evolutionary studies. their short life cycle, distribution in ecologically dynamic environments, and low agility make them favorable for genetic analyses. The species Hypsolebias antenori (Rivulidae), encountered in seasonal pools located in the semiarid region of Northeastern Brazil, has been the object of surveys with a view to study its ecological and behavioral aspects. This study reports on the karyotype patterns of this species, which represents the first contribution to the cytogenetics of this genus. The karyotype of this species is composed of 2n = 48 chromosomes (6m + 4sm + 36st; NF = 96); the heterochromatic regions are located in centromeric or pericentromeric position and are more pronounced in the nucleolar organizer regions. Two sites Ag-NORs/CMA+/DAPI were identified in the short arms of pairs 2 (metacentric) and 21 (subtelocentric). Unlike the other species of this family which show an evolution modulated by events of centric fusions, H. antenori shows the maintenance of a basal diploid number and the large number of bibrachial elements indicates karyotypic diversification derived by pericentric inversions. Cytogenetic analyzes in this species will provide new taxonomic markers capable of being utilized in conservation issues and systematics. PMID:24693249

  10. Controls on Extreme Droughts and Adaptation Strategies in Semiarid Regions

    NASA Astrophysics Data System (ADS)

    Scanlon, B. R.; Cook, C.; Fernando, D. N.; LeBlanc, M.

    2012-12-01

    Increasing vulnerability to droughts with reduced per capita water storage, particularly in semiarid regions, underscores the need for predictive understanding of drought controls and development of adaptation strategies for water resources management. In this study we evaluate causes of major droughts in southwest and southcentral US (California and Texas) and southeast Australia (Murray Darling Basin). Impacts of climate cycles (ENSO, PDO, AMO, NAO, IOD) and atmospheric circulation on drought initiation and persistence are examined. Effects of drought on surface water reservoir storage, groundwater storage, irrigation, and crop production are compared. Adaptation strategies being evaluated include water transfers among sectors, particularly from irrigated agriculture to other groups, increasing storage using managed aquifer recharge, water reuse, and development of new water sources (e.g. seawater desalination). It is critical to develop a broad portfolio of water sources to increase resilience to future droughts.

  11. The effect of deforestation on the regional temperature in Northeastern China

    NASA Astrophysics Data System (ADS)

    Yu, Lingxue; Zhang, Shuwen; Tang, Junmei; Liu, Tingxiang; Bu, Kun; Yan, Fengqin; Yang, Chaobin; Yang, Jiuchun

    2015-05-01

    Land cover change, as one of the most important driving forces to climate change, has become the research focus of the global environmental change research and global land project. More researchers studied on the global influence of Land-Use and Land-Cover Change and proved that land use change occurred at different temperature zones may produce different climate effects. For example, deforestation in tropical areas would lead to higher temperatures as the decreasing of evapotranspiration caused by the reduction of roughness and the decreasing of drag coefficient and leaf area index while, in boreal areas, similar deforestation would cause lower temperature as the increasing of albedo particularly during winter with the snow cover. However, the impact of deforestation in the temperate regions on the climate still existed uncertainty and the impacts of deforestation at different humidity conditions on climate has not explored yet. From this perspective, this article used Weather Research and Forecasting model to simulate the impact of deforestation on the temperature of Northeastern China. In this study, we designed two scenarios in July and December, respectively: One was simulated without human intervention, and the second one was simulated with the current forest covers. The results showed that the temperature in both summer and winter showed a decreasing trend when the conversion of forest to farmland occurred in northeastern China. In order to further explore the humidity impacts on the temperature, we performed sample analysis on humid, sub-humid, and semi-arid regions. According to the results, the maximum variation of temperature was found in humid areas, especially in December when the temperature decreased around 4-5 °C, while the change in semi-arid and sub-humid areas is relatively small.

  12. Modeling of Water balance in semiarid region of Mexico

    NASA Astrophysics Data System (ADS)

    González-Sosa, E.; Mastachi-Loza, C.; Medina-frutos, C.; Ramos-Salinas, N. M.

    2012-04-01

    Around the world water is becoming scarce, especially in the semiarid regions where there is a high inter-annual variability in the amount and distribution of the rainfall. Studies on this kind of environments would allow us to understand the mechanisms that determine the spatial and temporal distribution of the water balance components. The present study was carried out from October 2005 to October 2008 in three semiarid sites located in the south of the Mexican Plateau: El Carmen in Guanajuato State and Amazcala and Cadereyta in the State of Queretaro. The work aim was to provide a better understanding of the hydrological processes that occur in the semiarid ecosystems, specifically through two objectives (1) to quantify and to model the rainfall interception process (EI) employing an adequate sampling strategy and an evaluation of the models developed by Rutter et al. (1975) and Gash (1979) in two shrubs species: huisache (Acacia farnesisna) and mesquite (Prosopis laevigata) both, in situ and ex situ and (2) to quantify and model the water balance in order to define the distribution of the water and energy balance components in El Carmen and Cadereyta. For this purpose, the SiSPAT (Simple Soil Plant Atamosphere Transfer) model was used based on a parametrisation of the soil, plants and atmosphere components. It was found that EI represented between 20% and 22% of the total rainfall (PG). Gash's model reproduced EI with satisfactory efficiency (E>0.6), wind's speed and maximum intensity have a local effect on EI. It was also found that, using SiSPAT, the water balance components were particularly sensitive to parameters associated with the soil and the leaf area index. The model results showed that during the studied period, the annual evapotranspiration in Cadereyta was less than PG (-10 and -5%) and above PG for El Carmen (10 y 30%). Runoff and percolation at 5m were null. Finally in both sites there was a simulated loss of water stored in the soil. This, was

  13. 40 CFR 81.144 - Northeastern Virginia Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Air Quality Control Regions § 81.144 Northeastern Virginia Intrastate Air Quality Control Region. The Northeastern Virginia Intrastate Air Quality Control Region consists of the territorial area encompassed by the... 40 Protection of Environment 17 2010-07-01 2010-07-01 false Northeastern Virginia Intrastate...

  14. Mexican Fruit Fly Populations in the Semi-Arid Highlands of the Sierra Madre Oriental in Northeastern Mexico.

    PubMed

    Vanoye-Eligio, V; Mora-Olivo, A; Gaona-García, G; Reyes-Zepeda, F; Rocandio-Rodríguez, M

    2017-01-04

    The Mexican fruit fly, Anastrepha ludens Loew (Diptera: Tephritidae), is one of the most important pests of citrus in Mexico. We report the results of an analysis of A. ludens populations that inhabit the semi-arid highlands of the Sierra Madre Oriental in northeastern Mexico. This study aimed to provide information on population fluctuation of A. ludens and how it relates to climate variables, as well as insights into habitat and native parasitoids. Population peaked in the period July-November when ripe fruits of the wild host, Casimiroa pubescens Ramírez, were available. No adults were captured the rest of the year, suggesting that high populations depend on the availability of wild host fruit. No significant relationships between population fluctuation and climatic variables were observed, except for minimum temperature. Fruit samples of citron (Citrus medica L.), pomegranate (Punica granatum L.), and C. pubescens were collected to determine degree of infestation. Infestation levels (pupae/g) ranged between 0.0006 for citron, 0.0047 for pomegranate, and 0.0240 for C. pubescens. A native parasitoid of Tephritidae, Doryctobracon crawfordii (Viereck) (Braconidae), was identified. Parasitism percentage was calculated at 12.5% on C. pubescens fruits. No parasitoids were observed on citron or pomegranate fruit samples. These results contribute to knowledge on behavior of A. ludens native to temperate environments where no commercial hosts are available. Further research on host expansion of this pest in light of scenarios of global climate change is suggested.

  15. [Inventory of reptiles in 2 semi-arid zones from Northeastern of the Peninsula de Araya, Sucre State, Venezuela].

    PubMed

    Pablo Cornejo, E; Antulio Prieto, A

    2001-01-01

    The fauna of reptiles in two localities from Northeastern Peninsula de Araya (Guayacán and El Morahal), Sucre State, Venezuela, was evaluated. Both zones are characterized by a vegetation of thorny tropical mount type, and semiarid climate of scarce precipitations (less than 700 mm). Field trips were made between june 1997 and june 1998. The samples were collected both during day and night, with the aid of conventional accessories. The information was complemented with visual registrations and bibliography revision. A total of 21 species were captured and/or observed, distributed in 10 families belonging to 2 of the 3 orders present in Venezuela. The most important families from the point of view of the diversity of species, were the Gekkonidae (2.00 bits/species) for the lizards and the Colubridae (2.33 bits/species) among the snakes. It was also reported one species of tortoises and three of cinegetic interest, being Cnemidophorus lemniscatus, Ameiva bifrontata y Tropidurus hispidus the only species of constant presence during the study.

  16. Ethno-ornithology and conservation of wild birds in the semi-arid Caatinga of northeastern Brazil.

    PubMed

    Alves, Rômulo Romeu Nóbrega; Leite, Railson Cidennys Lourenço; Souto, Wedson Medeiros Silva; Bezerra, Dandara M M; Loures-Ribeiro, Alan

    2013-02-27

    The utilization of birds as pets has been recognized as one of the principal threats to global avifauna. Most of the information about the use and sale of birds as pets has been limited to areas of high biodiversity and whose impacts of anthropic actions have been widely broadcast internationally, for example for the Amazon Forest and forest remnants of Southeast Asia. The Caatinga predominates in the semi-arid region of Brazil, and is one of the semi-arid biomes with the greatest biological diversity in the world, where 511 species of birds exist. Many of these birds are used as pets, a common practice in the region, which has important conservationist implications but has been little studied. Therefore, the aim of the present study was to detail aspects of the use of birds as pets in a locality in the semi-arid region of Northeast Brazil. Information on the use of avifauna was obtained through interviews and visits to the homes of 78 wild bird keepers. A total of 41 species of birds were recorded, mostly of the families Emberizidae (n = 9 species), Columbidae (n = 7 species), Icteridae (n = 6 species) and Psittacidae (n = 3 species). The birds that were most often recorded were Paroaria dominicana (n = 79 especimens), Sporophila albogularis (n = 67), Aratinga cactorum (n = 49), Sporophila lineola (n = 36), Sicalis flaveola (n = 29) and Sporophila nigricollis (n = 27). The use of wild birds in the area studied, as an example of what occurs in other places in the semi-arid Northeast, demonstrates that such activities persist in the region, in spite of being illegal, and have been happening in clandestine or semi-clandestine manner. No statistically significant correlation were found between socioeconomic factors and keeping birds as pets reflects the cultural importance of this practice of rearing wild birds for pets in the region, which is widespread among the local population, independent of socioeconomic factors. Obviously, human pressure on the avifauna

  17. Ethno-ornithology and conservation of wild birds in the semi-arid Caatinga of northeastern Brazil

    PubMed Central

    2013-01-01

    The utilization of birds as pets has been recognized as one of the principal threats to global avifauna. Most of the information about the use and sale of birds as pets has been limited to areas of high biodiversity and whose impacts of anthropic actions have been widely broadcast internationally, for example for the Amazon Forest and forest remnants of Southeast Asia. The Caatinga predominates in the semi-arid region of Brazil, and is one of the semi-arid biomes with the greatest biological diversity in the world, where 511 species of birds exist. Many of these birds are used as pets, a common practice in the region, which has important conservationist implications but has been little studied. Therefore, the aim of the present study was to detail aspects of the use of birds as pets in a locality in the semi-arid region of Northeast Brazil. Information on the use of avifauna was obtained through interviews and visits to the homes of 78 wild bird keepers. A total of 41 species of birds were recorded, mostly of the families Emberizidae (n = 9 species), Columbidae (n = 7 species), Icteridae (n = 6 species) and Psittacidae (n = 3 species). The birds that were most often recorded were Paroaria dominicana (n = 79 especimens), Sporophila albogularis (n = 67), Aratinga cactorum (n = 49), Sporophila lineola (n = 36), Sicalis flaveola (n = 29) and Sporophila nigricollis (n = 27). The use of wild birds in the area studied, as an example of what occurs in other places in the semi-arid Northeast, demonstrates that such activities persist in the region, in spite of being illegal, and have been happening in clandestine or semi-clandestine manner. No statistically significant correlation were found between socioeconomic factors and keeping birds as pets reflects the cultural importance of this practice of rearing wild birds for pets in the region, which is widespread among the local population, independent of socioeconomic factors. Obviously

  18. Karst characterization in a semi-arid region using gravity, seismic, and resistivity geophysical techniques.

    SciTech Connect

    Barnhart, Kevin Scott

    2013-10-01

    We proposed to customize emerging in situ geophysical monitoring technology to generate time-series data during sporadic rain events in a semi-arid region. Electrodes were to be connected to wireless \

  19. Global synthesis of groundwater recharge in semiarid and arid regions

    USGS Publications Warehouse

    Scanlon, B.R.; Keese, K.E.; Flint, A.L.; Flint, L.E.; Gaye, C.B.; Edmunds, W.M.; Simmers, I.

    2006-01-01

    Global synthesis of the findings from ???140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique is widely used to estimate recharge. Average recharge rates estimated over large areas (40-374000 km2) range from 0.2 to 35 mm year-1, representing 0.1-5% of long-term average annual precipitation. Extreme local variability in recharge, with rates up to ???720 m year-1, results from focussed recharge beneath ephemeral streams and lakes and preferential flow mostly in fractured systems. System response to climate variability and land use/land cover (LU/LC) changes is archived in unsaturated zone tracer profiles and in groundwater level fluctuations. Inter-annual climate variability related to El Nin??o Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Nin??os (1977-1998) relative to periods dominated by La Nin??as (1941-1957). Enhanced recharge related to ENSO is also documented in Argentina. Climate variability at decadal to century scales recorded in chloride profiles in Africa results in recharge rates of 30 mm year-1 during the Sahel drought (1970-1986) to 150 mm year-1 during non-drought periods. Variations in climate at millennial scales in the SW US changed systems from recharge during the Pleistocene glacial period (??? 10 000 years ago) to discharge during the Holocene semiarid period. LU/LC changes such as deforestation in Australia increased recharge up to about 2 orders of magnitude. Changes from natural grassland and shrublands to dryland (rain-fed) agriculture altered systems from discharge (evapotranspiration, ET) to recharge in the SW US. The

  20. Global synthesis of groundwater recharge in semiarid and arid regions

    NASA Astrophysics Data System (ADS)

    Scanlon, Bridget R.; Keese, Kelley E.; Flint, Alan L.; Flint, Lorraine E.; Gaye, Cheikh B.; Edmunds, W. Michael; Simmers, Ian

    2006-10-01

    Global synthesis of the findings from 140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique is widely used to estimate recharge. Average recharge rates estimated over large areas (40-374 000 km2) range from 0.2 to 35 mm year-1, representing 0.1-5% of long-term average annual precipitation. Extreme local variability in recharge, with rates up to 720 m year-1, results from focussed recharge beneath ephemeral streams and lakes and preferential flow mostly in fractured systems. System response to climate variability and land use/land cover (LU/LC) changes is archived in unsaturated zone tracer profiles and in groundwater level fluctuations. Inter-annual climate variability related to El Niño Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Niños (1977-1998) relative to periods dominated by La Niñas (1941-1957). Enhanced recharge related to ENSO is also documented in Argentina. Climate variability at decadal to century scales recorded in chloride profiles in Africa results in recharge rates of 30 mm year-1 during the Sahel drought (1970-1986) to 150 mm year-1 during non-drought periods. Variations in climate at millennial scales in the SW US changed systems from recharge during the Pleistocene glacial period (10 000 years ago) to discharge during the Holocene semiarid period. LU/LC changes such as deforestation in Australia increased recharge up to about 2 orders of magnitude. Changes from natural grassland and shrublands to dryland (rain-fed) agriculture altered systems from discharge (evapotranspiration, ET) to recharge in the SW US. The impact of LU

  1. The relationship between anthropogenic dust and population over global semi-arid regions

    NASA Astrophysics Data System (ADS)

    Guan, Xiaodan; Huang, Jianping; Zhang, Yanting; Xie, Yongkun; Liu, Jingjing

    2016-04-01

    Although anthropogenic dust has received more attention from the climate research community, its dominant role in the production process is still not identified. In this study, we analysed the relationship between anthropogenic dust and population density/change over global semi-arid regions and found that semi-arid regions are major source regions in producing anthropogenic dust. The results showed that the relationship between anthropogenic dust and population is more obvious in cropland than in other land cover types (crop mosaics, grassland, and urbanized regions) and that the production of anthropogenic dust increases as the population density grows to more than 90 persons km-2. Four selected semi-arid regions, namely East China, India, North America, and North Africa, were used to explore the relationship between anthropogenic dust production and regional population. The most significant relationship between anthropogenic dust and population occurred in an Indian semi-arid region that had a greater portion of cropland, and the high peak of anthropogenic dust probability appeared with 220 persons km-2 of population density and 60 persons km-2 of population change. These results suggest that the influence of population on production of anthropogenic dust in semi-arid regions is obvious in cropland regions. However, the impact does not always have a positive contribution to the production of anthropogenic dust, and overly excessive population will suppress the increase of anthropogenic dust. Moreover, radiative and climate effects of increasing anthropogenic dust need more investigation.

  2. Groundwater safe yield in semi-arid regions

    NASA Astrophysics Data System (ADS)

    Portoghese, I.; Giuliano, G.; Vurro, M.

    2003-04-01

    In many places around the world groundwater resources represent the only way to overcome the water scarcity during dry years. Even when water demand relies on well designed interconnected reservoir systems, extended and long-lasting meteorological droughts are likely to take place causing heavy socio-economic losses. In the semi-arid regions of the Mediterranean, the strong inter/intra-annual variability of rainfall together with a water demanding cropping policy has led to a massive groundwater exploitation. The unpredictability of climate variables at the (space-time) management scale and the high non-linearity of hydrological processes controlling the natural recharge make the evaluation of sound groundwater exploitation plans a warning challenge for the years to come. Using a simplified numerical model for the soil water balance calculation (with a distributed approach), able to yield month-by-month estimation of crop water irrigation requirements (dry months), runoff yield and groundwater recharge rates (wet months), we simulated the dynamic interaction which links climate variability, irrigation demands, groundwater withdrawals and natural recharge for a meaningful period. The study area located in Southern Italy (hydrogeological unit of Tavoliere, 4737 Km2, Northern Apulia Region) is almost completely cropped and the irrigation plants are well developed thanks to a valuable system of artificial lake reservoirs. Under the hypothesis of a complete satisfaction of the irrigation demand by the surface water supply in the average hydrologic year, we selected, from the rainfall record, a set of years composed by a period of deficit and a subsequent of surplus with the condition that the cumulative rainfall deficit is at last recovered. The deficit between irrigation requirement and reservoir net yield was considered to be supplied by groundwater withdrawals throughout the modelled period and, therefore, the difference between annual natural recharge and

  3. 40 CFR 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Quality Control Region. 81.79 Section 81.79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.79 Northeastern Oklahoma Intrastate Air Quality Control Region. The Metropolitan Tulsa Intrastate Air Quality Control Region has been renamed the Northeastern Oklahoma...

  4. 40 CFR 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Quality Control Region. 81.79 Section 81.79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.79 Northeastern Oklahoma Intrastate Air Quality Control Region. The Metropolitan Tulsa Intrastate Air Quality Control Region has been renamed the Northeastern Oklahoma...

  5. 40 CFR 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Quality Control Region. 81.79 Section 81.79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.79 Northeastern Oklahoma Intrastate Air Quality Control Region. The Metropolitan Tulsa Intrastate Air Quality Control Region has been renamed the Northeastern Oklahoma...

  6. 40 CFR 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Quality Control Region. 81.79 Section 81.79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.79 Northeastern Oklahoma Intrastate Air Quality Control Region. The Metropolitan Tulsa Intrastate Air Quality Control Region has been renamed the Northeastern Oklahoma...

  7. 40 CFR 81.79 - Northeastern Oklahoma Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Quality Control Region. 81.79 Section 81.79 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Air Quality Control Regions § 81.79 Northeastern Oklahoma Intrastate Air Quality Control Region. The Metropolitan Tulsa Intrastate Air Quality Control Region has been renamed the Northeastern Oklahoma...

  8. 40 CFR 81.240 - Northeastern Plains Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Air Quality Control Regions § 81.240 Northeastern Plains Intrastate Air Quality Control Region. The Northeastern Plains Intrastate Air Quality Control Region (New Mexico) consists of the territorial area... Quality Control Region. 81.240 Section 81.240 Protection of Environment ENVIRONMENTAL PROTECTION...

  9. Vertical and temporal variation in phytoplankton assemblages correlated with environmental conditions in the Mundaú reservoir, semi-arid northeastern Brazil.

    PubMed

    Lira, G A S T; Moura, A N; Vilar, M C P; Cordeiro-Araújo, M K; Bittencourt-Oliveira, M C

    2014-08-01

    The goal of this study was to analyse the vertical structure of the phytoplankton community at the Mundaú reservoir, located in the semi-arid region of northeastern Brazil, and to correlate it to environmental conditions over two distinct seasons, dry and rainy. Samples were collected bimonthly at eight depths in the dry and rainy season for analyses of the physical and chemical variables of the water, as well as density, abundance, dominance, species diversity index and equitability of the community. Analysis of variance (ANOVA-two way) was used to analyse the vertical and seasonal differences, and Canonical Correspondence Analysis (CCA) was used to assess associations between phytoplankton and environmental variables Cylindrospermopsis raciborskii (Woloszynska) Seenaya and Subba Raju was the only dominant species and Geitlerinema amphibium (C. Agardh) Anagnostidis, Merismopedia punctata Meyen and Synedra rumpens Kützing. Others six taxa were abundant in at least one of the samples. Distinct vertical distribution patterns were observed for the abundant taxa between depths and seasons. The cyanobacteria, with the exception of C. raciborskii, showed similar seasonal patterns, with higher densities in the dry season. The CCA showed a strong correlation between the density of the phytoplanktonic species and abiotic variables. The vertical changes in abundant taxa revealed distinct patterns regulated by the variation in the environmental factors that were directly linked to seasonality, with the success of one or more species being dependent on their life strategies and ecological needs. The present study restates the importance of environmental and seasonal factors for phytoplankton composition and distribution in a freshwater tropical reservoir through a vertical gradient.

  10. Prevalence and determinants of child undernutrition and stunting in semiarid region of Brazil

    PubMed Central

    Correia, Luciano Lima; Silva, Anamaria Cavalcante e; Campos, Jocileide Sales; Andrade, Francisca Maria de Oliveira; Machado, Márcia Maria Tavares; Lindsay, Ana Cristina; Leite, Álvaro Jorge Madeiro; Rocha, Hermano Alexandre Lima; da Cunha, Antonio José Ledo Alves

    2014-01-01

    OBJECTIVE To analyze the evolution in the prevalence and determinants of malnutrition in children in the semiarid region of Brazil. METHODS Data were collected from two cross-sectional population-based household surveys that used the same methodology. Clustering sampling was used to collect data from 8,000 families in Ceará, Northeastern Brazil, for the years 1987 and 2007. Acute undernutrition was calculated as weight/age < -2 standard deviation (SD); stunting as height/age < -2 SD; wasting as weight/height < -2 SD. Data on biological and sociodemographic determinants were analyzed using hierarchical multivariate analyses based on a theoretical model. RESULTS A sample of 4,513 and 1,533 children under three years of age, in 1987 and 2007, respectively, were included in the analyses. The prevalence of acute malnutrition was reduced by 60.0%, from 12.6% in 1987 to 4.7% in 2007, while prevalence of stunting was reduced by 50.0%, from 27.0% in 1987 to 13.0% in 2007. Prevalence of wasting changed little in the period. In 1987, socioeconomic and biological characteristics (family income, mother’s education, toilet and tap water availability, children’s medical consultation and hospitalization, age, sex and birth weight) were significantly associated with undernutrition, stunting and wasting. In 2007, the determinants of malnutrition were restricted to biological characteristics (age, sex and birth weight). Only one socioeconomic characteristic, toilet availability, remained associated with stunting. CONCLUSIONS Socioeconomic development, along with health interventions, may have contributed to improvements in children’s nutritional status. Birth weight, especially extremely low weight (< 1,500 g), appears as the most important risk factor for early childhood malnutrition. PMID:24789633

  11. Tropical Warm Semi-Arid Regions Expanding Over Temperate Latitudes In The Projected 21st Century

    NASA Astrophysics Data System (ADS)

    Rajaud, A.; de Noblet, N. I.

    2015-12-01

    Two billion people today live in drylands, where extreme climatic conditions prevail, and natural resources are limited. Drylands are expected to expand under several scenarios of climatic change. However, relevant adaptation strategies need to account for the aridity level: it conditions the equilibrium tree-cover density, ranging from deserts (hyper-arid) to dense savannas (sub-humid). Here we focus on the evolution of climatically defined warm semi-arid areas, where low-tree density covers can be maintained. We study the global repartition of these regions in the future and the bioclimatic shifts involved. We adopted a bioclimatological approach based on the Köppen climate classification. The warm semi-arid class is characterized by mean annual temperatures over 18°C and a rainfall-limitation criterion. A multi-model ensemble of CMIP5 projections for three representative concentration pathways was selected to analyze future conditions. The classification was first applied to the start, middle and end of the 20th and 21st centuries, in order to localize past and future warm semi-arid regions. Then, time-series for the classification were built to characterize trends and variability in the evolution of those regions. According to the CRU datasets, global expansion of the warm semi-arid area has already started (~+13%), following the global warming trend since the 1900s. This will continue according to all projections, most significantly so outside the tropical belt. Under the "business as usual" scenario, the global warm semi-arid area will increase by 30% and expand 12° poleward in the Northern Hemisphere, according to the multi-model mean. Drying drives the conversion from equatorial sub-humid conditions. Beyond 30° of latitude, cold semi-arid conditions become warm semi-arid through warming, and temperate conditions through combined warming and drying processes. Those various transitions may have drastic but also very distinct ecological and sociological

  12. The effect of microphytes on the spectral reflectance of vegetation in semiarid regions

    SciTech Connect

    Karnieli, A.; Shachak, M.; Tsoar, H.; Zaady, E.; Kaufman, Y.; Danin, A.; Porter, W.

    1996-08-01

    The normalized difference vegetation index (NDVI), which is derived from satellite sensor images, is widely used as a measure of vegetation and ecosystem dynamics, change in land use, desertification, and climatic change processes on a regional or global scale. Surprisingly, in semiarid regions, relatively high values of NDVI were measured in landscapes where little, if any, photosynthetic activity of higher plants exists. The authors tested the hypothesis that the high NDVI values may be caused by the photosynthetic activity of microphytes (lower plants), consisting of mosses, lichens, algae, and cyanobacteria, which cover most of the rock and soil surfaces in semiarid regions. They found that the spectral reflectance curves of lower plants can be similar to those of the higher ones and their derived NDVI values can be as high as 0.30 units. The authors conclude that, in semiarid environments, the reflectance of lower plant communities may lead to misinterpretation of the vegetation dynamics and overestimation of ecosystem productivity.

  13. Thin scale ecohydrological data and relations at semi-arid regions: a methodological approach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In semi-arid regions worldwide the vegetation is organized in patches surrounded by bare soil with marked differences in their soil properties that play important roles in runoff and infiltration. Chihuahuan-Sonoran and Patagonian Monte deserts regions show floristic similarity greater than that ex...

  14. Minimal mechanisms for vegetation patterns in semiarid regions

    PubMed Central

    Martínez-García, Ricardo; Calabrese, Justin M.; Hernández-García, Emilio; López, Cristóbal

    2014-01-01

    The minimal ecological requirements for the fomation of regular vegetation patterns in semiarid systems have been recently questioned. Against the general belief that a combination of facilitative and competitive interactions is necessary, recent theoretical studies suggest that, under broad conditions, non-local competition among plants alone may induce patterns. In this paper, we review results along this line, presenting a series of models that yield spatial patterns when finite-range competition is the only driving force. A preliminary derivation of this type of model from a more detailed one that considers water–biomass dynamics is also presented. PMID:25246686

  15. Understanding sources of uncertainty in flash-flood forecasting for semi-arid regions 1913

    Technology Transfer Automated Retrieval System (TEKTRAN)

    About one-third of the earth’s landsurface is located in arid or semi-arid regions, often in areas suffering severely from the negative impacts of desertification and population pressure. Reliable hydrological forecasts across spatial and temporal scales are crucial in order to achieve water securit...

  16. Modeling Soil Organic Carbon in a Semiarid Region of Kazakhstan Using EPIC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inappropriate land use and soil mismanagement produced wide-scale soil and environmental degradation to the short-grass steppe ecosystem in the semiarid region of Kazakhstan. We used the Environmental Policy Integrated Climate (EPIC) model to study long-term impacts of land use changes and soil mana...

  17. Windblown soil crust formation under light rainfall in a semiarid region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many soils in arid and semi-arid regions of the world are affected by crusting, the process of forming a compact layer or thin mantle of consolidated material at the soil surface. Our objective was to evaluate the effect of rainfall quantity on crust formation of five soil types prominent in the Col...

  18. Efficiency of snake sampling methods in the Brazilian semiarid region.

    PubMed

    Mesquita, Paula C M D; Passos, Daniel C; Cechin, Sonia Z

    2013-09-01

    The choice of sampling methods is a crucial step in every field survey in herpetology. In countries where time and financial support are limited, the choice of the methods is critical. The methods used to sample snakes often lack objective criteria, and the traditional methods have apparently been more important when making the choice. Consequently researches using not-standardized methods are frequently found in the literature. We have compared four commonly used methods for sampling snake assemblages in a semiarid area in Brazil. We compared the efficacy of each method based on the cost-benefit regarding the number of individuals and species captured, time, and financial investment. We found that pitfall traps were the less effective method in all aspects that were evaluated and it was not complementary to the other methods in terms of abundance of species and assemblage structure. We conclude that methods can only be considered complementary if they are standardized to the objectives of the study. The use of pitfall traps in short-term surveys of the snake fauna in areas with shrubby vegetation and stony soil is not recommended.

  19. Survey of Ehrlichia canis, Babesia spp. and Hepatozoon spp. in dogs from a semiarid region of Brazil.

    PubMed

    Rotondano, Tereza Emmanuelle de Farias; Almeida, Herta Karyanne Araújo; Krawczak, Felipe da Silva; Santana, Vanessa Lira; Vidal, Ivana Fernandes; Labruna, Marcelo Bahia; de Azevedo, Sérgio Santos; Ade lmeida, Alzira Maria Paiva; de Melo, Marcia Almeida

    2015-01-01

    This study assessed the occurrence of Ehrlichia spp., Babesia spp. and Hepatozoon spp. infections in 100 tick-harboring dogs from a semiarid region of the State of Paraíba, Northeastern Brazil. Blood samples and ticks were collected from the animals, and a questionnaire was submitted to dog owners to obtain general data. Blood samples were used to perform hemogram, direct blood smear and immunological and molecular hemoparasite detection. The 1,151 ticks collected were identified as Rhipicephalus sanguineus; direct smears revealed E. canis-like morulae in the monocytes of 4% (4/100) of the non-vaccinated female dogs, and 34% and 25% of the dogs tested positive for Ehrlichia canis by indirect immunofluorescence assay (IFA) and polymerase chain reaction (PCR), respectively. Blood smear examination revealed Babesia-suggestive merozoites in the erythrocytes of 2% (2/100) of the animals. Babesia vogeli was detected by PCR in ten animals (10%) and was correlated with young age (p = 0.007) and thrombocytopenia (p = 0.01). None of the animals showed Hepatozoon spp. positivity. These results indicate that E. canis is the main tick-borne canine pathogen in the study area and provide the first report of B. vogeli infection in dogs from Paraiba State.

  20. [Effects of environmental factors on litter decomposition in arid and semi-arid regions: A review].

    PubMed

    Wang, Xin-Yuan; Zhao, Xue-Yong; Li, Yu-Lin; Lian, Jie; Qu, Hao; Yue, Xiang-Fei

    2013-11-01

    Litter decomposition is one of the important biochemical processes in arid and semi-arid regions, and a key component of regional nutrient turnover and carbon cycling, which is mainly affected by climate, litter quality, and decomposer community. In order to deeply understand the relationships between litter decomposition and environmental factors in arid and semi-arid regions, this paper summarized the research progress in the effects of abiotic factors (soil temperature, precipitation, and ultraviolet-B radiation) and biotic factors (litter quality, soil microbial and animal composition and community structure) on the litter decomposition in these regions. Among the factors, precipitation and ultraviolet-B radiation are considered to be the main limiting factors of litter decomposition. In arid and semi-arid regions, precipitation can significantly increase the litter decomposition rate in a short term, while the photo-degradation induced by ultraviolet-B radiation, due to the strong and long-term radiation, can increase the decomposition rate of terrestrial litter. Litter quality, soil microbial and animal composition and community structure are mainly affected by the type of ecosystems in a long term. However, the affecting mechanisms of these environmental factors on litter decomposition are still not very clear. It was suggested that the future litter ecological research should be paid more attention to the interaction of environmental factors under climate change, the variations of litter decomposition at different spatial scales, and the establishment of litter decomposition models in relation to the synergistic interactions of multiple factors.

  1. A zoological catalogue of hunted reptiles in the semiarid region of Brazil.

    PubMed

    Nóbrega Alves, Rômulo Romeu; Pereira Filho, Gentil Alves; Silva Vieira, Kleber; Silva Souto, Wedson Medeiros; Mendonça, Lívia Emanuelle Tavares; Montenegro, Paulofernandoguedespereira; Almeida, Waltécio de Oliveira; Silva Vieira, Washington Luiz

    2012-07-30

    The variety of interactions between human cultures and herpetofauna is the subject matter of Ethnoherpetology, a subdivision of Ethnozoology. In the semi-arid region of Brazil, many reptiles interact with human communities because of their utility or because of the risks they represent. These interactions have obvious implications for the conservation of reptiles from this region. In this context, ethnoherpetology studies are crucial because they serve as subsidies for guiding strategies for the handling and conservation of reptiles. This paper presents ethnozoological and taxonomic informations of hunted reptiles in the semiarid region of Brazil and analyse the implications on conservation that are related to the interactions between people and reptiles in this region. Taxonomic keys to identifying recorded reptiles are provided. Records of humans interacting with 38 reptile species that belong to 31 genuses and 16 families have been found. The groups with the largest numbers of recorded species were snakes (18 species), and this group was followed in number by lizards (13), chelonians (4), and crocodilians (3). The reptiles that were recorded may be used for the following purposes: medicinal purposes (24 species), food (13 species), ornamental or decorative purposes (11 species), in magical/religious practices (10 species), and as pets (10 species). Some species (n = 16) may have multiple uses. Furthermore, more than half of the species (n = 19) are commonly killed because they are considered potentially dangerous. Strategies for conserving the reptiles of the Brazilian semi-arid region must reconcile and integrate human and conservation needs.

  2. The Dynamics of a Semi-Arid Region in Response to Climate and Water - Use Policy

    NASA Technical Reports Server (NTRS)

    Mustard, John F.; Hamburg, Steve; Grant, John A.; Manning, Sara J.; Steinwand, Aaron; Howard, Chris

    2000-01-01

    The objectives of this project were to determine the response of semi-arid ecosystems to the combined forcings of climate variability and anthropogenic stress. Arid and semi-arid systems encompass close to 40% of the worlds land surface. The ecology of these regions are principally limited by water, and as the water resources wax and wane, so should the health and vigor of the ecosystems. Water, however, is a necessary and critical resource for humans living in these same regions. Thus for many and and semi-arid regions the natural systems and human systems are in direct competition for a limited resource. Increasing competition through development of and and semi-arid regions, export of water resources, as well as potential persistent changes in weather patterns are likely to lead to fundamental changes in carrying capacity, resilience, and ecology of these regions. A detailed understanding of these systems respond to forcing on a regional and local scale is required in order to better prepare for and manage future changes in the availability of water. In the Owens Valley CA, decadal changes in rainfall and increased use of groundwater resources by Los Angles (which derives 60-70% of its water from this region) have resulted in a large-scale experiment on the impacts of these changes in semi-arid ecosystems. This project works directly with the Inyo County Water Department (local water authority) and the Los Angles Department of Water and Power (regional demand on water resources) to understand changes, their causes, and impacts. Very detailed records have been kept for a number of selected sites in the valley which provide essential ground truth. These results are then scaled up through remote sensed data to regions scale to assess large scale patterns and link them to the fundamental decisions regarding the water resources of this region. A fundamental goal is to understand how resilient the native ecosystems are to large changes in water resources. Are they are

  3. Contribution of Afforestation Practices to Changing Hydrology in Arid and Semi-arid Regions

    NASA Astrophysics Data System (ADS)

    Xie, X.; Meng, S.; Li, J.

    2014-12-01

    Arid and semi-arid regions are generally susceptible to land degeneration due to limited precipitation and high potential evapotranspiration (ET). Afforestation has been assumed to be a feasible strategy to conserve water and to improve ecological environment. For example, the Northern China, as a typical arid and semi-arid region has experienced large-scale and long-term afforestation practices since the early 1980s. The land cover has been altered to some degree as tree planting with increasing greenness. However, the effectiveness of afforestation might not be as expected due to the interference of climate change. In this study, we attempted to quantify the contribution of afforestation practices to the hydrological system in the Northern China. A macro-scale hydrological model, i.e., the Variable Infiltration Capacity (VIC), was employed to simulate ET, soil moisture and runoff for the period 1959 - 2009. Fractional simulation scenarios were designed regarding different conditions of land cover and climate changes. The results indicate that the land cover has minor impact on the variability of hydrological variables at regional scale, comparing with the climate change. Particularly, the decreasing precipitation plays a dominant role in shaping the trends of ET, soil moisture and runoff. The findings have significant implications for the implementation of the afforestation practices and for the management of water resources in arid and semi-arid regions.

  4. Basin-scale solar irradiance estimates in semiarid regions using GOES 7

    SciTech Connect

    Pinker, R.T.; Laszlo, I.; Kustas, W.P.

    1994-05-01

    This paper evaluates the ability of satellite observations from GOES 7 to provide basin-scale surface solar irradiance (SW) estimates in a semiarid region during a period of strong convective activity with highly variable cloud conditions. A physical inference model is used to derive the SW. Information of surface albedo is a prerequisite in all such models. In this study the albedo is first derived from the clear sky radiances as observed from the same satellite. 29 refs., 12 figs, 5 tabs.

  5. Will water scarcity in semiarid regions limit hydraulic fracturing of shale plays?

    NASA Astrophysics Data System (ADS)

    Scanlon, Bridget R.; Reedy, Robert C.; Nicot, Jean Philippe

    2014-12-01

    There is increasing concern about water constraints limiting oil and gas production using hydraulic fracturing (HF) in shale plays, particularly in semiarid regions and during droughts. Here we evaluate HF vulnerability by comparing HF water demand with supply in the semiarid Texas Eagle Ford play, the largest shale oil producer globally. Current HF water demand (18 billion gallons, bgal; 68 billion liters, bL in 2013) equates to ˜16% of total water consumption in the play area. Projected HF water demand of ˜330 bgal with ˜62 000 additional wells over the next 20 years equates to ˜10% of historic groundwater depletion from regional irrigation. Estimated potential freshwater supplies include ˜1000 bgal over 20 yr from recharge and ˜10 000 bgal from aquifer storage, with land-owner lease agreements often stipulating purchase of freshwater. However, pumpage has resulted in excessive drawdown locally with estimated declines of ˜100-200 ft in ˜6% of the western play area since HF began in 2009-2013. Non-freshwater sources include initial flowback water, which is ≤5% of HF water demand, limiting reuse/recycling. Operators report shifting to brackish groundwater with estimated groundwater storage of 80 000 bgal. Comparison with other semiarid plays indicates increasing brackish groundwater and produced water use in the Permian Basin and large surface water inputs from the Missouri River in the Bakken play. The variety of water sources in semiarid regions, with projected HF water demand representing ˜3% of fresh and ˜1% of brackish water storage in the Eagle Ford footprint indicates that, with appropriate management, water availability should not physically limit future shale energy production.

  6. Modeling water scarcity and droughts for policy adaptation to climate change in arid and semiarid regions

    NASA Astrophysics Data System (ADS)

    Kahil, Mohamed Taher; Dinar, Ariel; Albiac, Jose

    2015-03-01

    Growing water extractions combined with emerging demands for environment protection increase competition for scarce water resources worldwide, especially in arid and semiarid regions. In those regions, climate change is projected to exacerbate water scarcity and increase the recurrence and intensity of droughts. These circumstances call for methodologies that can support the design of sustainable water management. This paper presents a hydro-economic model that links a reduced form hydrological component, with economic and environmental components. The model is applied to an arid and semiarid basin in Southeastern Spain to analyze the effects of droughts and to assess alternative adaptation policies. Results indicate that drought events have large impacts on social welfare, with the main adjustments sustained by irrigation and the environment. The water market policy seems to be a suitable option to overcome the negative economic effects of droughts, although the environmental effects may weaken its advantages for society. The environmental water market policy, where water is acquired for the environment, is an appealing policy to reap the private benefits of markets while protecting ecosystems. The current water management approach in Spain, based on stakeholders' cooperation, achieves almost the same economic outcomes and better environmental outcomes compared to a pure water market. These findings call for a reconsideration of the current management in arid and semiarid basins around the world. The paper illustrates the potential of hydro-economic modeling for integrating the multiple dimensions of water resources, becoming a valuable tool in the advancement of sustainable water management policies.

  7. A comparative study of the effects of albedo change on drought in semi-arid regions

    NASA Technical Reports Server (NTRS)

    Charney, J.; Quirk, W. J.; Chow, S.-H.; Kornfield, J.

    1977-01-01

    Numerical simulation studies of the effects of changes in albedo on rainfall involve comparisons of semiarid areas, lying at the boundary between a major desert and an adjacent monsoonal region, with areas of the same size located within the monsoonal region itself. The sensitivity of the rainfall to the ground hydrology was determined by performing the albedo simulations with two different evapotranspiration parameterizations, one giving too high evaporation over land and the other giving negligible evaporation over land. The evaporation rate is, in general, found to have as important an effect as changes in albedo. The mechanism by which an increase of albedo reduces the rainfall during conditions of high evaporation is considered.

  8. Modeling water balance distribution in a natural semiarid region of central Mexico using a SVAT model

    NASA Astrophysics Data System (ADS)

    Mastachi-Loza, C. A.; Braud, I.; Gonzalez-Sosa, E.; Centro de Investigaciones Del Agua de Querétaro

    2010-12-01

    Around the world water is becoming insufficient, especially in the semiarid regions where there is a high inter-annual variability in the amount and distribution of the rainfall. Studies on this kind of environments would allow us to understand the mechanisms that determine the spatial and temporal distribution of the water balance components. The study was carried out from October 2005 to October 2008 in two semiarid sites located in the south of the Mexican Plateau: El Carmen in Guanajuato State and Cadereyta in Queretaro State. The work aim was to provide a better understanding of the hydrological processes that occur in semiarid ecosystems, quantifying and modeling the water balance in order to define the distribution of the water and energy balance components in El Carmen and Cadereyta. For this purpose, the SiSPAT (Simple Soil Plant Atmosphere Transfer) model was used based on a parameterization of the soil, plants and atmosphere components. It was found that, using SiSPAT, the water balance components were particularly sensitive to parameters associated with the soil and the leaf area index. The model results showed that during the studied period, the annual evapotranspiration in Cadereyta was less than PG (-10 and -5%) and above PG for El Carmen (10 y 30%). Runoff and percolation at 5m were null. Finally in both sites there was a simulated loss of water stored in the soil.

  9. A comparison of the relative efficiency of total and cold-extractable stream sediment chemistry in exploration geochemical surveys in a semi-arid climate, Collo area, north-eastern Algeria

    NASA Astrophysics Data System (ADS)

    Bounessah, Mustapha; Atkin, Brian P.

    1994-08-01

    A stream sediment survey was conducted in a semi-arid area in north-eastern Algeria. The survey includes a comparative study between results obtained from total analysis (XRF) and cold-extraction analysis (AAS), and assesses the relative success of the two data sets in delineating known mineralization and bedrock types. Samples were collected from ephemeral streams and water-bearing rivers and a sampling density of 1 sample km -2 has been found to be effective in delineating most of the known mineralization and serpentinite bedrock. Anomalies occur mainly in the ephemeral streams but decay downstream after 1000 m, whereas in rivers values only rarely reach concentration levels above the regional background. Known lead, zinc and copper bearing veins, as well as the serpentinites, were well delineated by both analytical techniques. However, the iron mineralization could only be confirmed by the total analysis data set. In addition, new anomalies, similar to those of the sulphide mineralization, were discovered in the SW of the study area. Finally, it is suggested that the cold-extraction technique may offer an acceptable and cheaper alternative to total analysis for outlining serpentinites (cxCo and cxNi) and base-metal mineralization (cxCu, cxPb and cxZn).

  10. A zoological catalogue of hunted reptiles in the semiarid region of Brazil

    PubMed Central

    2012-01-01

    The variety of interactions between human cultures and herpetofauna is the subject matter of Ethnoherpetology, a subdivision of Ethnozoology. In the semi-arid region of Brazil, many reptiles interact with human communities because of their utility or because of the risks they represent. These interactions have obvious implications for the conservation of reptiles from this region.In this context, ethnoherpetology studies are crucial because they serve as subsidies for guiding strategies for the handling and conservation of reptiles. This paper presents ethnozoological and taxonomic informations of hunted reptiles in the semiarid region of Brazil and analyse the implications on conservation that are related to the interactions between people and reptiles in this region. Taxonomic keys to identifying recorded reptiles are provided. Records of humans interacting with 38 reptile species that belong to 31 genuses and 16 families have been found. The groups with the largest numbers of recorded species were snakes (18 species), and this group was followed in number by lizards (13), chelonians (4), and crocodilians (3). The reptiles that were recorded may be used for the following purposes: medicinal purposes (24 species), food (13 species), ornamental or decorative purposes (11 species), in magical/religious practices (10 species), and as pets (10 species). Some species (n = 16) may have multiple uses. Furthermore, more than half of the species (n = 19) are commonly killed because they are considered potentially dangerous. Strategies for conserving the reptiles of the Brazilian semi-arid region must reconcile and integrate human and conservation needs. PMID:22846258

  11. Semiarid landscapes response to Aeolian processes during Holocene in Baikal Region

    NASA Astrophysics Data System (ADS)

    Dan'ko, Lidia; Opekunova, Marina

    2010-05-01

    Arid and semiarid landscapes play a significant role in global climate, biogeochemical, and hydrological processes. Regional analysis of the past aeolian processes is essential for improve our understanding of how various landscape and ecosystems responded to climate change in the past. Our investigation presents details on sand dunes and on loess-like sediments. The study areas are situated in the northern part of Baikal Region (Eastern Siberia). In its depressions, the so-called Barguzinskaya and Tunkinskaya Valley surrounded mountain ranges local dunefieds and loess-like sediments have developed. Present climate in the study areas is continental, characterized by low precipitation(mean annual 250-450 mm) and wide annual range of temperature. Field investigations indicate that the Holocene deposits of the Barguzinskaya and Tunkinskaya Valley are sealed the pedo-sedimentary interface. The analytical results suggest that one's represents a changeover from intensified soil formation to accelerated aeolian dust accumulation. The original content of calcium carbonate and gypsum at the base of some sections of loess-like sediments indicates the aeolian origin of these sediments. In whole, the soil horizons are a proof for humid phases. The change was forced by climatic aridity. Absolute dating of the organogenic components of soils (14C) indicate the age positions of the arid and humid climate phases. Our results indicate not only 1-4 long-time episodes of aeolian dust accumulation during the Holocene, but shot-time aeolian accumulation episodes, that were specific for Late Holocene. For example, in the Tunkinskaya Valley the Late Holocene soil formation replaced by aeolian deposit at 1700 - 1900, 800 and 200-250 years ago, in the Barguzinskaya Valley - about 3100 - 2900, 2300 and 600 years ago. It can be concluded that a periodical formation of the aeolian deposits in the semiarid landscapes during Holocene can be postulated. Aeolian and loess-like sediments of the

  12. Regional lead dynamics in the Northeastern United States - Local versus regional industrial influences

    NASA Astrophysics Data System (ADS)

    Wreschnig, A. J.; Bain, D. J.; Green, M. B.; Ruffing, C. M.; Adams, L. E.

    2009-12-01

    Elevated concentrations of lead in sediments are a phenomenon that has been primarily examined in the context of leaded gasoline usage and prehistoric smelting. However, regional trends in the Northeastern United States have not been well explained, particularly between the years of 1800 and 1920. Sediment core data from throughout the region were synthesized to characterize regional Pb deposition. There is a consistent increase in sediment Pb concentrations independent of geographic location that begins to occur around 1870. This increase occurs before the advent of leaded gasoline, requiring apportionment to other sources. Previous studies have used smaller scale distributions of Pb sediment concentrations to estimate the contribution of various anthropogenic sources including coal combustion, Pb smelting, and industrial waste. However, the robustness of these estimates when scaled up to an entire region is questionable. To improve understanding at larger scales, local, regional, and national metal production and coal combustion records are compared to sediment core data across the region. It is expected that both Midwestern smelting, undergoing great intensification during this time period, and local production of Pb intensive goods will be strongly correlated with Pb concentrations in sediments. Further, it is expected the large regional increase in coal combustion should influence regional Pb flux less than local metal production.

  13. Assessment of the performance of water harvesting systems in semi-arid regions

    NASA Astrophysics Data System (ADS)

    Lasage, Ralph

    2016-04-01

    Water harvesting is widely practiced and has the potential to improve water availability for domestic and agricultural use in semi-arid regions. New funds are becoming available to stimulate the implementation of water harvesting projects, for meeting the Sustainable Development Goals and to help communities to adapt to climate change. For this, it is important to understand which factors determine the success of water harvesting techniques under different conditions. For this, we review the literature, including information on the crop yield impacts of water harvesting projects in semi-arid Africa and Asia. Results show that large water harvesting structures (> 500 m3) are less expensive than small structures, when taking into account investment costs, storage capacity and lifetimes. We also find that water harvesting improves crop yields significantly, and that the relative impact of water harvesting on crop yields is largest in low rainfall years. We also see that the governance, technical knowledge and initial investment are more demanding for the larger structures than for smaller structures, which may affect their spontaneous adoption and long term sustainability when managed by local communities. To support the selection of appropriate techniques, we present a decision framework based on case specific characteristics. This framework can also be used when reporting and evaluating the performance of water harvesting techniques, which is up to now quite limited in peer reviewed literature. Based on Bouma, J., Hegde, S.E., Lasage, R., (2016). Assessing the returns to water harvesting: A meta-analysis. Agricultural Water Management 163, 100-109. Lasage, R., Verburg P.H., (2015). Evaluation of small scale water harvesting techniques for semi-arid environments. Journal of Arid Environments 118, 48-57.

  14. Future Water Management in the South Platte River Basin: Impacts of Hydraulic Fracturing, Population, Agriculture, and Climate Change in a Semi-Arid Region.

    NASA Astrophysics Data System (ADS)

    Walker, E. L.; Hogue, T. S.; Anderson, A. M.; Read, L.

    2015-12-01

    In semi-arid basins across the world, the gap between water supply and demand is growing due to climate change, population growth, and shifts in agriculture and unconventional energy development. Water conservation efforts among residential and industrial water users, recycling and reuse techniques and innovative regulatory frameworks for water management strive to mitigate this gap, however, the extent of these strategies are often difficult to quantify and not included in modeling water allocations. Decision support systems (DSS) are purposeful for supporting water managers in making informed decisions when competing demands create the need to optimize water allocation between sectors. One region of particular interest is the semi-arid region of the South Platte River basin in northeastern Colorado, where anthropogenic and climatic effects are expected to increase the gap between water supply and demand in the near future. Specifically, water use in the South Platte is impacted by several high-intensity activities, including unconventional energy development, i.e. hydraulic fracturing, and large withdrawals for agriculture; these demands are in addition to a projected population increase of 100% by 2050. The current work describes the development of a DSS for the South Platte River basin, using the Water Evaluation and Planning system software (WEAP) to explore scenarios of how variation in future water use in the energy, agriculture, and municipal sectors will impact water allocation decisions. Detailed data collected on oil and gas water use in the Niobrara shale play will be utilized to predict future sector use. We also employ downscaled climate projections for the region to quantify the potential range of water availability in the basin under each scenario, and observe whether or not, and to what extent, climate may impact management decisions at the basin level.

  15. 40 CFR 81.144 - Northeastern Virginia Intrastate Air Quality Control Region.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR PROGRAMS (CONTINUED) DESIGNATION OF AREAS FOR AIR QUALITY PLANNING PURPOSES Designation of... Northeastern Virginia Intrastate Air Quality Control Region consists of the territorial area encompassed by the boundaries of the following jurisdictions or described area (including the territorial area of...

  16. Development of a Remotely-sensed Soil Heat Flux Parameterization for Natural Landscapes in Semi-arid Regions

    NASA Astrophysics Data System (ADS)

    Kim, J.; Scott, R.; Hogue, T.

    2007-12-01

    Due to the difficulties in directly measuring soil heat flux (G), research on empirical estimation has moved toward use of a strong association between soil heat flux and net radiation (Rnet). The majority of these studies are concentrated on the estimation of soil heat flux from mature agricultural areas in semi-arid regions due to the high demand for irrigation water. However, natural land surfaces, the largest fraction of semi-arid and arid regions, have not been well studied with regards to soil heat flux estimation. Therefore, application of the previously developed empirical equations to natural land surfaces results in large uncertainty in soil heat flux estimates. This study explores development of an empirical relationship that is well-suited for natural landscapes within semi-arid areas in order to provide a more thorough assessment of regional evaporation (i.e. water consumption) in water-limited regions. Particularly, we seek to develop an empirical relationship between soil heat flux and net radiation when observations from the mid-day polar orbiting satellites (i.e. Terra/Aqua) are available. MODIS-derived components such as vegetation indices, albedo and surface temperature are being used to characterize this relationship over a set of flux tower sites in southern Arizona. Evaluation of existing soil heat flux schemes as well as results from validation of a new formulation suitable for use in natural landscapes within semi-arid regions will be presented.

  17. Salinity and freshwater discharge determine rotifer distribution at the Mossoró River Estuary (Semiarid Region of Brazil).

    PubMed

    Medeiros, A M A; Barbosa, J E L; Medeiros, P R; Rocha, R M; Silva, L F

    2010-08-01

    The present study aimed at evaluating differences in rotifer distribution in three estuarine zones in an inverse estuary located in the Semiarid Region of Brazil. Zones were chosen based on their proximity to the ocean and river border as a means of reflecting a horizontal salinity gradient. High freshwater discharge during the rainy season was the major determinant of rotifer composition. On the other hand, due to higher salinity values during the dry season, very low values of species richness and abundance were observed in all zones. Therefore, the study highlights the constraints of salinity and the positive influence of seasonality and river proximity on rotifer species in a semiarid estuarine environment.

  18. Triatoma ryckmani (Hemiptera: Reduviidae) in the epiphyte Tillandsia xerographica (Bromeliaceae) in the semiarid region of Guatemala.

    PubMed

    Marroquín, Ricardo; Monroy, Carlota; Jaenson, Thomas G T

    2004-05-01

    For the first time, the reduviid bug Triatoma ryckmani Zeledón and Ponce (Hemiptera; Reduviidae) was recorded to inhabit the epiphyte Tillandsia xerographica Rohweder (Bromeliaceae) in the semiarid region of Guatemala. These bromeliads grow mainly in drought-resistant trees with rough bark such as Pereskia lychnidiflora (Cactaceae). In our study site, we investigated 30 T. xerographica, and 53 specimens of T. ryckmani were found. Most T. ryckmani (68.5%) were unfed. Ants (Formicidae) were the predominant (92.2%) insect taxon in T. xerographica. Other insects such as Blattidae (3.0%), Reduviidae (T. ryckmani: 2.5%), Blaberidae (2.2%), Gryllidae (0.1%), and Acrididae (0.1%) were recorded in the bromeliads. T. xerographica is illegally commercialized without previous inspection. This may cause accidental introduction of T. ryckmani to houses and to other countries.

  19. Quantifying atmospheric methane emissions from the Haynesville, Fayetteville, and northeastern Marcellus shale gas production regions

    NASA Astrophysics Data System (ADS)

    Peischl, J.; Ryerson, T. B.; Aikin, K. C.; Gouw, J. A.; Gilman, J. B.; Holloway, J. S.; Lerner, B. M.; Nadkarni, R.; Neuman, J. A.; Nowak, J. B.; Trainer, M.; Warneke, C.; Parrish, D. D.

    2015-03-01

    We present measurements of methane (CH4) taken aboard a NOAA WP-3D research aircraft in 2013 over the Haynesville shale region in eastern Texas/northwestern Louisiana, the Fayetteville shale region in Arkansas, and the northeastern Pennsylvania portion of the Marcellus shale region, which accounted for the majority of Marcellus shale gas production that year. We calculate emission rates from the horizontal CH4 flux in the planetary boundary layer downwind of each region after subtracting the CH4 flux entering the region upwind. We find 1 day CH4 emissions of (8.0 ± 2.7) × 107 g/h from the Haynesville region, (3.9 ± 1.8) × 107 g/h from the Fayetteville region, and (1.5 ± 0.6) × 107 g/h from the Marcellus region in northeastern Pennsylvania. Finally, we compare the CH4 emissions to the total volume of natural gas extracted from each region to derive a loss rate from production operations of 1.0-2.1% from the Haynesville region, 1.0-2.8% from the Fayetteville region, and 0.18-0.41% from the Marcellus region in northeastern Pennsylvania. The climate impact of CH4 loss from shale gas production depends upon the total leakage from all production regions. The regions investigated in this work represented over half of the U.S. shale gas production in 2013, and we find generally lower loss rates than those reported in earlier studies of regions that made smaller contributions to total production. Hence, the national average CH4 loss rate from shale gas production may be lower than values extrapolated from the earlier studies.

  20. [Effect of Biochar on Soil Greenhouse Gas Emissions in Semi-arid Region].

    PubMed

    Guo, Yan-liang; Wang, Dan-dan; Zheng, Ji-yong; Zhao, Shi-wei; Zhang, Xing-chang

    2015-09-01

    This study aimed to investigate the effects of biochar addition on the emission of greenhouse gases from farmland soil in semi-arid region. Through an in-situ experiments, the influence of sawdust biochar(J) and locust tree skin biochar (H) at three doses (1%, 3%, and 5% of quality percentage) on C2, CH4 and N2O emissions were studied within the six months in the south of Ningxiaprovince. The results indicated that soil CO2 emission flux was slightly increased with the addition doses for both biochars, and the averaged CO2 emission flux for sawdust and locust tree skin biochar was enhanced by 1. 89% and 3. 34% compared to the control, but the difference between treatments was not statistically significant. The soil CH4 emission was decreased with the increasing of biochar doses, by 1. 17%, 2. 55%, 4. 32% for J1, J3, J5 and 2. 35%, 5. 83%, 7. 32% for H1, H3, H5, respectively. However, the difference was statistically significant only for J5, H3 and H5 treatments (P <0. 05). Across addition doses, there was no apparent effect on soil N2O emission. Our study indicated that the biochar has no significant influence on soil CO2 and N2O emissions within six months in semi-arid region and can significantly influence soil CH4 emissions (P < 0. 05). As for biochar type, the locust tree skin biochar is significantly better than the sawdust biochar in terms of restraining CH4 emission(P = 0. 048).

  1. Remotely-Sensed Regional-Scale Evapotranspiration of a Semi-Arid Great Basin Desert and its Relationship to Geomorphology, Soils, and Vegetation

    NASA Technical Reports Server (NTRS)

    Laymon, C.; Quattrochi, D.; Malek, E.; Hipps, L.; Boettinger, J.; McCurdy, G.

    1997-01-01

    Landsat Thematic Mapper data is used to estimate instantaneous regional-scale surface water and energy fluxes in a semi-arid Great Basin desert of the western United States. Results suggest that it is possible to scale from point measurements of environmental state variables to regional estimates of water and energy exchange. This research characterizes the unifying thread in the classical climate-topography-soil-vegetation relation-the surface water and energy balance-through maps of the partitioning of energy throughout the landscape. The study was conducted in Goshute Valley of northeastern Nevada, which is characteristic of most faulted graben valleys of the Basin and Range Province of the western United States. The valley comprises a central playa and lake plain bordered by alluvial fans emanating from the surrounding mountains. The distribution of evapotranspiration (ET) is lowest in the middle reaches of the fans where the water table is deep and plants are small, resulting in low evaporation and transpiration. Highest ET occurs in the center of the valley, particularly in the playa, where limited to no vegetation occurs, but evaporation is relatively high because of a shallow water table and silty clay soil capable of large capillary movement. Intermediate values of ET are associated with large shrubs and is dominated by transpiration.

  2. Remotely-Sensed Regional-Scale Evapotranspiration of a Semi-Arid Great Basin Desert and its Relationship to Geomorphology, Soils, and Vegetation

    NASA Technical Reports Server (NTRS)

    Laymon, C.; Quattrochi, D.; Malek, E.; Hipps, L.; Boettinger, J.; McCurdy, G.

    1998-01-01

    Landsat thematic mapper data are used to estimate instantaneous regional-scale surface water and energy fluxes in a semi-arid Great Basin desert of the western United States. Results suggest that it is possible to scale from point measurements of environmental state variables to regional estimates of water and energy exchange. This research characterizes the unifying thread in the classical climate-topography-soil-vegetation relation -the surface water and energy balance-through maps of the partitioning of energy throughout the landscape. The study was conducted in Goshute Valley of northeastern Nevada, which is characteristic of most faulted graben valleys of the Basin and Range Province of the western United States. The valley comprises a central playa and lake plain bordered by alluvial fans emanating from the surrounding mountains. The distribution of evapotranspiration (ET) is lowest in the middle reaches of the fans where the water table is deep and plants are small, resulting in low evaporation and transpiration. Highest ET occurs in the center of the valley, particularly in the playa, where limited to no vegetation occurs, but evaporation is relatively high because of a shallow water table and silty clay soil capable of large capillary movement. Intermediate values of ET are associated with large shrubs and is dominated by transpiration.

  3. Calibration of the maximum carboxylation velocity (Vcmax) using data mining techniques and ecophysiological data from the Brazilian semiarid region, for use in Dynamic Global Vegetation Models.

    PubMed

    Rezende, L F C; Arenque-Musa, B C; Moura, M S B; Aidar, S T; Von Randow, C; Menezes, R S C; Ometto, J P B H

    2016-06-01

    The semiarid region of northeastern Brazil, the Caatinga, is extremely important due to its biodiversity and endemism. Measurements of plant physiology are crucial to the calibration of Dynamic Global Vegetation Models (DGVMs) that are currently used to simulate the responses of vegetation in face of global changes. In a field work realized in an area of preserved Caatinga forest located in Petrolina, Pernambuco, measurements of carbon assimilation (in response to light and CO2) were performed on 11 individuals of Poincianella microphylla, a native species that is abundant in this region. These data were used to calibrate the maximum carboxylation velocity (Vcmax) used in the INLAND model. The calibration techniques used were Multiple Linear Regression (MLR), and data mining techniques as the Classification And Regression Tree (CART) and K-MEANS. The results were compared to the UNCALIBRATED model. It was found that simulated Gross Primary Productivity (GPP) reached 72% of observed GPP when using the calibrated Vcmax values, whereas the UNCALIBRATED approach accounted for 42% of observed GPP. Thus, this work shows the benefits of calibrating DGVMs using field ecophysiological measurements, especially in areas where field data is scarce or non-existent, such as in the Caatinga.

  4. Estimation of evapotranspiration for different land covers in a Brazilian semi-arid region: A case study of the Brígida River basin, Brazil

    NASA Astrophysics Data System (ADS)

    Santos, Celso Augusto Guimarães; Silva, Richarde Marques da; Silva, Alexandro Medeiros; Brasil Neto, Reginaldo Moura

    2017-03-01

    In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to compute the surface albedo, vegetation indices (NDVI, SAVI and LAI), surface temperature, soil heat flux and evapotranspiration (ET) over two contrasting years (dry and wet) in the Brígida River basin, a semi-arid region of north-eastern Brazil. The actual ET was computed during satellite overpass and was integrated for 24 h on a pixel-by-pixel basis for the daily ET distribution. Due to the topographic effects, an attempt was also made to incorporate DEM information to estimate the net radiation. The land cover types identified in the watershed are cropland, bare land, dense canopy, grassland, and caatinga vegetation. In order to study the variation among the biophysical parameters and ET, two-way analysis of variance (ANOVA) was used. The ET calculated by SEBAL ranged between 2.46 and 6.87 mm/day for the dry year (1990) and 1.31 and 6.84 mm/day for the wet year (2009) for the river basin. The results showed that a reduction in vegetation cover is evident in the temporal and spatial analysis over the studied periods in the region and that these facts influence the values of the energy balance and ET. The results showed significant differences in the variables of land cover type and year at the probability level of 0.05 for all land cover types.

  5. Water Balance Study on a Semiarid Regional Landscape in South Texas: Effects of Anthropogenic Land Disturbance

    NASA Astrophysics Data System (ADS)

    Camarena, C.; Ren, J.; Jones, K.

    2004-12-01

    While extensive vegetation manipulation has been encouraged by many administrators and extension groups, its effect on the water balance is complex and the hypothesis that removal of woody plants consistently reduces evapotranspiration, increases soil water content, and water yield remains unproven. This project focuses on examination of the effects of various land management practices on the overall water balance for semiarid regional landscapes. The project location is at the Wellhausen Ranch Research Station located near Laredo, TX, consisting of 5,280 acres of shrub landscape dominated by honey mesquite shrub species. This ranch has undergone various land disturbances such as root plowing and cattle overgrazing that have caused damage to the vegetation and natural communities. Five research sites were chosen within the ranch including a control site, a gravel dominated site, a root plowed site, an undisturbed site, and a second research site with different vegetative cover to represent different land use environments. Parameters that are being measured for the water balance study include precipitation, soil moisture, surface runoff, evaporation, and evapotranspiration. Preliminary results show that for the period of January to September of 2004, temperatures in the Wellhausen Ranch range from 29.1 ºF to 106.9 ºF, indicating hot summers and mild winters. 68 rainfall events have occurred, which resulted in 16.24 inches of total precipitation. Patterns were detected in soil moisture profiles reflecting the differences of soil moisture at different depths in the soil. Analysis of variance (ANOVA) indicates significant differences in the soil moisture in the five research sites. In addition, micro-lysimeter results show higher evaporation rates in the gravel dominated and the second research sites. These preliminary results indicate a potentially significant influence of anthropogenic land disturbance on a landscape water balance in the semiarid Nueces River basin.

  6. Determine the optimum spectral reflectance of juniper and pistachio in arid and semi-arid region

    NASA Astrophysics Data System (ADS)

    Fadaei, Hadi; Suzuki, Rikie

    2012-11-01

    Arid and semi-arid areas of northeast Iran cover about 3.4 million ha are populated by two main tree species, the broadleaf Pistacia vera. L (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environmentally important but genetically essential as seed sources for pistachio production in orchards. In this study, we estimated the optimum spectral reflectance of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. In this research spectral reflectance are able to specify of multispectral from Advanced Land Observing Satellite (ALOS) that provided by JAXA. These data included PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, has one band with a wavelength of 0.52-0.77 μm and AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, has four multispectral bands: blue (0.42-0.50 μm), green (0.52-0.60 μm), red (0.61-0.69 μm), and near infrared (0.76-0.89 μm). Total ratio vegetation index (TRVI) of optimum spectral reflectance of juniper and pistachio have been evaluated. The result of TRVI for Pistachio and juniper were (R2= 0.71 and 0.55). I hope this research can provide decision of managers to helping sustainable management for arid and semi-arid regions in Iran.

  7. Understanding uncertainty in distributed flash flood forecasting for semiarid regions 1909

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Semi-arid flash floods pose a significant danger for life and property in the US. One effective way to mitigate flood risk is by implementing a rainfall-runoff model in a real-time forecast and warning system. This study used a physically based, distributed semi-arid rainfall-runoff model driven by ...

  8. Ground swelling and shrinking in a semi-arid region induced by weather and climate changes

    NASA Astrophysics Data System (ADS)

    Dafalla, Muawia

    2013-04-01

    This research study presents a close up view of the engineering behaviour of surface and subsurface soils as associated to weather conditions in a semi-arid region. The expansive clay shale and salty shale soils in the region of Tabuk in Saudi Arabia is linked to serious damage to light structures including buildings, roads and various light structures. The expansive soils expand when moisture increase is introduced and shrink when drying or losing moisture. The scale of damage is highlighted through various examples from the region. The objective of this work is to provide a guide to construction industry on the most appropriate construction times based on the environmental trends and engineering properties of soils in the area. A comprehensive study including testing and survey of the literature data were put together to predict the expansion and shrinkage behaviour of Tabuk near surface soil formation. The swell and compressibility tests were performed for a series of samples. Average compressibility and swell index were obtained. Soil water characteristic information for typical clay is presented. Ten years of environmental and metrological records were gathered and analysed for frequency and intensity of rainfall, humidity and temperature. Periods of significant variations and impact on the soil volume behaviour were grouped and compared over the whole ten years period. The construction on a pre-wetted ground and on entirely dry formation was discussed. The approach followed for selecting appropriate construction times is given. Keywords: swelling; shrinkage; shale; temperature; precipitation and humidity.

  9. Impact of sublimation losses in the mass balance of glaciers in semi-arid mountain regions

    NASA Astrophysics Data System (ADS)

    Ayala, Alvaro; Pellicciotti, Francesca; Burlando, Paolo; MacDonell, Shelley; McPhee, James

    2016-04-01

    Glaciers in semiarid mountain regions may lose an important part of their winter snow accumulation through sublimation processes that are enhanced by the high-elevation, intense radiation and dry atmosphere of these environments. As glaciers in these regions secure freshwater resources to lower valleys during summer and drought periods, it is important to advance in a detailed quantification of their sublimation losses. However, logistical concerns and complex meteorological features make the measuring and modelling of glacier mass balances a difficult task. In this study, we estimated the spring-summer mass balances of Tapado and Juncal Norte glaciers in the semiarid Andes of north-central Chile by running a distributed energy balance model that accounts for melt, refreezing and sublimation from the surface and blowing snow. Meteorological input data were available from on-glacier Automatic Weather Stations (AWS) that were installed during the ablation season of years 2005-06, 2008-09, 2013-14 and 2014-15. Snow pits, ablation stakes and a time-lapse camera that provided surface albedo were also available. Distributed air temperature and wind speed were dynamically downscaled from NASA MERRA reanalysis using the software WINDSIM and validated against the data from the AWSs. The rest of the meteorological variables were distributed using statistical relations with air temperature derived from the AWSs data. Initial snow conditions were estimated using satellite images and distributed manual snow depth measurements. Preliminary results show that total ablation diminishes with elevation and that, during the early ablation season (October-November), melt is the main ablation component below 4500 m with sublimation dominating the ablation above this elevation. Above 4500 m an important fraction of meltwater refreezes during night. As the ablation season advances (December-February), melt extends to higher elevations, refreezing plays a smaller role and sublimation is

  10. Nuclear Hybrid Energy Systems Regional Studies: West Texas & Northeastern Arizona

    SciTech Connect

    Garcia, Humberto E.; Chen, Jun; Kim, Jong Suk; McKellar, Michael George; Deason, Wesley R; Richard B. Vilim; Bragg-Sitton, Shannon M.; Boardman, Richard D.

    2015-04-01

    The primary objective of this study is to conduct a preliminary dynamic analysis of two realistic hybrid energy systems (HES) including a nuclear reactor as the main baseload heat generator (denoted as nuclear HES or nuclear hybrid energy systems [[NHES]) and to assess the local (e.g., HES owners) and system (e.g., the electric grid) benefits attainable by the application of NHES in scenarios with multiple commodity production and high penetration of renewable energy. It is performed for regional cases not generic examples based on available resources, existing infrastructure, and markets within the selected regions. This study also briefly addresses the computational capabilities developed to conduct such analyses, reviews technical gaps, and suggests some research paths forward.

  11. An ecological engineering approach for keeping water from reaching interred wastes in arid or semiarid regions

    SciTech Connect

    Anderson, J.E.

    1997-12-31

    This paper describes application of a soil-plant cover system (SPCS) to preclude water from reaching interred wastes in arid and semiarid regions. Where potential evapotranspiration far exceeds precipitation, water can be kept from reaching buried wastes by (1) providing a sufficiently deep cap of soil to store precipitation that falls while plants are dormant and (2) maintaining plant cover to deplete soil moisture during the growing season, thereby emptying the storage reservoir. Research at the Idaho National Engineering Laboratory (INEL) has shown that 2 m of soil is adequate to store moisture from snowmelt and spring rains. Healthy stands of perennial grasses and shrubs adapted to the INEL climate use all available soil moisture, even during a very wet growing season. However, burrowing by small mammals or ants may affect the performance of a SPCS by increasing infiltration of water. Intrusion barriers of gravel and cobble can be used to restrict burrowing, but emplacement of such barriers affects soil moisture storage and plant rooting depths. A replicated field experiment to investigate the implications of those effects is in progress. Incorporation of an SPCS should be considered in the design of isolation barriers for shallow land burial of hazardous wastes in and regions.

  12. Validation of Comet assay in Oregon-R and Wild type strains of Drosophila melanogaster exposed to a natural radioactive environment in Brazilian semiarid region.

    PubMed

    Verçosa, Cícero Jorge; Moraes Filho, Aroldo Vieira de; Castro, Ícaro Fillipe de Araújo; Santos, Robson Gomes Dos; Cunha, Kenya Silva; Silva, Daniela de Melo E; Garcia, Ana Cristina Lauer; Navoni, Julio Alejandro; Amaral, Viviane Souza do; Rohde, Claudia

    2017-03-21

    Natural radiation of geological origin is a common phenomenon in Brazil, a country where radioactive agents such as uranium may be often found. As an unstable atom, uranium undergoes radioactive decay with the generation of a series of decay by-products, including radon, which may be highly genotoxic and trigger several pathological processes, among which cancer. Because it is a gas, radon may move freely between cracks and gaps in the ground, seeping upwards into the buildings and in the environment. In this study, two Drosophila melanogaster Meigen (Diptera, Drosophilidae) strains called Oregon-R and Wild (collected in a non-radioactive environment) were exposed to atmospheric radiation in the Lajes Pintadas city, in the semiarid zone of northeastern Brazil. After six days of environmental exposure, the organisms presented genetic damage significantly higher than that of the negative control group. The genotoxic effects observed reinforce the findings of other studies carried out in the same region, which warn about the environmental risks related to natural radioactivity occurrence. The results also validate the use of the Comet assay in hemocytes of D. melanogaster as a sensitive test to detect genotoxicity caused by natural radiation, and the use of a recently collected D. melanogaster strain in the environmental of radon.

  13. [Irrigated perimeters as a geopolitical strategy for the development of the semi-arid region and its implications for health, labor and the environment].

    PubMed

    Pontes, Andrezza Graziella Veríssimo; Gadelha, Diego; Freitas, Bernadete Maria Coêlho; Rigotto, Raquel Maria; Ferreira, Marcelo José Monteiro

    2013-11-01

    An analysis was made of irrigated perimeters as a geopolitical strategy for expanding Brazilian agricultural frontiers and the "development" of the northeastern semi-arid region with respect to social determinants in health in rural communities. Research was conducted in the Chapada do Apodi in the states of Ceará and Rio Grande do Norte between 2007 and 2011. Various research techniques and tools were adopted, such as research-action, ethnographic studies, questionnaires and laboratory exams, water contamination analyses, social cartography and focal groups. In the context of agribusiness expansion, it was revealed that public policies of irrigation have had consequences for health, labor and the environment with the implementation of the Jaguaribe-Apodi Irrigated Perimeter in Ceará. The social and environmental conflict and resistance in the phase prior to the installation of the Santa Cruz do Apodi Irrigated Perimeter in Rio Grande do Norte was significant as it had consequences for the health-disease process on rural communities. It is important for the evaluation of public irrigation policies to consider the impacts of the perimeters on the lifestyle, labor, health and the environment of the affected territories.

  14. Assessment of pesticide residues in two arable soils from the semi-arid and subtropical regions of China.

    PubMed

    Wang, Ligang; Zhao, Zhenhua; Jiang, Xin; Wu, Jinshui; Martens, Dieter

    2005-10-01

    The residues of 31 chlorinated hydrocarbons (CHCs), 25 chlorophenols (CPs), 30 organophosphorus (OP) and pyrethroid (PRT) in two arable soils from the semi-arid and subtropical regions of China were assessed. Data obtained indicate that the main compounds of CHC pesticide residues in the semi-arid soil were 4,4'-DDE (25.3 ng/g) and beta-HCH (14.1 ng/g), which totally accounted to about 90% of total CHC residues detected. The total content of CHC residues detected in the subtropical soil was only 3.1 ng/g, of which approximately 50% was beta-HCH. However, the total content of CP residues in both of the soils was about 11 ng/g. In the semi-arid soil, only parathion-methyl amongst the 30 compounds of OP and PRT residues was detected (32.5 ng/g), whilst malathion and parathion-methyl (8.7 and 17.7 ng/g, respectively) detected in the subtropical soil. Based on these results, it was suggested the environmental risk of pesticide residues ranked in an order as CHCs (mainly as 4,4'-DDE, beta-HCH) > OP (parathion-methyl) > CPs for the semi-arid soil, and as OPs (parathion-methyl and malathion) > CPs > CHCs (beta-HCH) for the subtropical soil.

  15. Environmental and socioeconomic benefits and limitations of water harvesting techniques in semiarid regions

    NASA Astrophysics Data System (ADS)

    Díaz-Pereira, Elvira; Asunción Romero-Díaz, María; de Vente, Joris

    2016-04-01

    Under climate change, sustainable management of soil and water resources is increasingly important, especially in rainfed agroecosystems of semiarid environments. Water harvesting refers to a range of techniques for the collection and management of flood or rainwater for domestic and agricultural use and for water retention in natural ecosystems. Water harvesting represents a good example of sustainable management of water resources that contribute to water and food security. However, there are often environmental and socioeconomic constraints for implementation of water harvesting techniques, so each condition asks for a specific solution. Here we aim to highlight the environmental and socioeconomic benefits, requirements and limitations of different water harvesting techniques and to characterize their implications for provisioning, regulating, supporting, and cultural ecosystem services. We reviewed 62 water harvesting techniques for semiarid regions extracted from the WOCAT (World Overview of Conservation Approaches and Technologies) database. We discuss aspects related to: i) human and environmental characteristics, ii) cost-benefit ratio during implementation and maintenance phases, iii) socioeconomic and environmental impacts at local and regional scales, and, iv) impacts on ecosystem services. Our review reveals that water harvesting represents very diverse methods of collecting and managing floodwaters and surface runoff. We grouped techniques as 'floodwater harvesting', 'macro-catchment water harvesting', 'micro-catchment water harvesting', and 'rooftop and courtyard' water harvesting. Almost half of all technologies originates from traditional knowledge. The implementation of water harvesting is generally positive on the short-term, to very positive on the long-term, while its maintenance is very positive at short and long-term. However, perception depends on the type of water harvesting and local conditions. Most relevant socioeconomic benefits from

  16. Aiming towards improved flood forecasting: Identification of an adequate model structure for a semi-arid and data-scarce region

    NASA Astrophysics Data System (ADS)

    Pilz, Tobias; Francke, Till; Bronstert, Axel

    2015-04-01

    A lot of effort has already been put into the development of forecasting systems to warn people of approaching flood events. Such systems, however, are influenced by various sources of uncertainty which constrain the skill of forecasts. The main goal of this study is the identification, quantification and reduction of uncertainties to provide improved early warnings with adequate lead times in a data-scarce region with strong seasonality of the hydrological regime. This includes the setup of hydrological models and post-processing of simulation results by mathematical means such as data assimilation. The focus area is the Jaguaribe watershed in northeastern Brazil. The region is characterized by a seasonal climate with strong inter-annual variation and recurrent droughts. To ensure a secure water supply also during the dry season several thousand small and some large reservoirs have been constructed. On the other hand, floods caused by heavy rain events are an issue as well. This topic, however, so far has hardly been considered by the scientific community and until today no flood forecasting system exists for that region. To identify the most appropriate model structure for the catchment the process-based hydrological model for semi-arid environments WASA was implemented into the eco-hydrological simulation environment ECHSE. The environment consists of a generic part providing data types and simulation methods, and a problem-specific part where the user can implement different model formulations. This provides the possibility to test various process realisations under consistent input and output data structures. The most appropriate model structure can then be determined by statistical means such as Bayesian model averaging. Subsequently, forecast results may be updated by post-processing and/or data assimilation. Furthermore, methods of data fusion can be used to combine measurements of different quality and resolution, such as in-situ and remotely sensed data

  17. Peach response to water deficit in a semi-arid region

    NASA Astrophysics Data System (ADS)

    Paltineanu, C.; Septar, L.; Moale, C.; Nicolae, S.; Nicola, C.

    2013-09-01

    During three years a deficit irrigation experiment was performed on peach response under the semi-arid conditions of south-eastern Romania. Three sprinkler-irrigated treatments were investigated: fully irrigated, deficit irrigation treatment, and non-irrigated control treatment. Soil water content ranged between 60 and 76% of the plant available soil water capacity in fully irrigated, between 40 and 62% in deficit irrigation treatment, and between 30 and 45% in control. There were significant differences in fruit yield between the treatments. Irrigation water use efficiency was maximum in deficit irrigation treatment. Fruit yield correlated significantly with irrigation application. Total dry matter content, total solids content and titrable acidity of fruit were significantly different in the irrigated treatments vs. the control. Significant correlation coefficients were found between some fruit chemical components. For the possible future global warming conditions, when water use becomes increasingly restrictive, deficit irrigation will be a reasonable solution for water conservation in regions with similar soil and climate conditions.

  18. Deforestation impacts on soil organic carbon stocks in the Semiarid Chaco Region, Argentina.

    PubMed

    Villarino, Sebastián Horacio; Studdert, Guillermo Alberto; Baldassini, Pablo; Cendoya, María Gabriela; Ciuffoli, Lucía; Mastrángelo, Matias; Piñeiro, Gervasio

    2017-01-01

    Land use change affects soil organic carbon (SOC) and generates CO2 emissions. Moreover, SOC depletion entails degradation of soil functions that support ecosystem services. Large areas covered by dry forests have been cleared in the Semiarid Chaco Region of Argentina for cropping expansion. However, deforestation impacts on the SOC stock and its distribution in the soil profile have been scarcely reported. We assessed these impacts based on the analysis of field data along a time-since-deforestation-for-cropping chronosequence, and remote sensing indices. Soil organic C was determined up to 100cm depth and physically fractionated into mineral associated organic carbon (MAOC) and particulate organic C (POC). Models describing vertical distribution of SOC were fitted. Total SOC, POC and MAOC stocks decreased markedly with increasing cropping age. Particulate organic C was the most sensitive fraction to cultivation. After 10yr of cropping SOC loss was around 30%, with greater POC loss (near 60%) and smaller MAOC loss (near 15%), at 0-30cm depth. Similar relative SOC losses were observed in deeper soil layers (30-60 and 60-100cm). Deforestation and subsequent cropping also modified SOC vertical distribution. Soil organic C loss was negatively associated with the proportion of maize in the rotation and total crop biomass inputs, but positively associated with the proportion of soybean in the rotation. Without effective land use polices, deforestation and agricultural expansion can lead to rapid soil degradation and reductions in the provision of important ecosystem services.

  19. Antibacterial, Antioxidant, and Anticholinesterase Activities of Plant Seed Extracts from Brazilian Semiarid Region

    PubMed Central

    Farias, Davi Felipe; Souza, Terezinha Maria; Viana, Martônio Ponte; Soares, Bruno Marques; Cunha, Arcelina Pacheco; Vasconcelos, Ilka Maria; Ricardo, Nágila Maria Pontes Silva; Ferreira, Paulo Michel Pinheiro; Melo, Vânia Maria Maciel; Carvalho, Ana Fontenele Urano

    2013-01-01

    The antimicrobial, antioxidant, and anticholinesterase activities of ethanolic seed extracts of twenty-one plant species from Brazilian semiarid region were investigated. The extracts were tested for antimicrobial activity against six bacteria strains and three yeasts. Six extracts presented activity against the Gram (−) organism Salmonella choleraesuis and the Gram (+) organisms Staphylococcus aureus and Bacillus subtilis. The MIC values ranged from 4.96 to 37.32 mg/mL. The Triplaris gardneriana extract presented activity against the three species, with MIC values 18.8, 13.76, and 11.15 mg/mL, respectively. Five extracts presented antioxidant activity, with EC50 values ranging from 69.73 μg/mL (T. gardneriana) to 487.51 μg/mL (Licania rigida). For the anticholinesterase activity, eleven extracts were capable of inhibiting the enzyme activity. From those, T. gardneriana, Parkia platycephala and Connarus detersus presented the best activities, with inhibition values of 76.7, 71.5, and 91.9%, respectively. The extracts that presented antimicrobial activity were tested for hemolytic assay against human A, B, and O blood types and rabbit blood. From those, only the Myracrodruon urundeuva extract presented activity (about 20% of hemolysis at the lowest tested concentration, 1.9 µg/mL). Infrared spectroscopy of six representative extracts attested the presence of tannins, polyphenols, and flavonoids, which was confirmed by a qualitative phytochemical assay. PMID:24386637

  20. Predictability and prediction of summer rainfall in the arid and semi-arid regions of China

    NASA Astrophysics Data System (ADS)

    Xing, Wen; Wang, Bin

    2016-09-01

    Northwest China (NWC) is an arid and semi-arid region where climate variability and environmental changes are sensitive to precipitation. The present study explores sources and limits of predictability of summer precipitation over NWC using the predictable mode analysis (PMA) of percentage of rainfall anomaly data. Two major modes of NWC summer rainfall variability are identified which are tied to Eurasian continental scale precipitation variations. The first mode features wet northern China corresponding to dry central Siberia and wet Mongolia, which is mainly driven by tropical Pacific sea surface temperature anomalies (SSTA). The second mode features wet western China reflecting wet Central Asia and dry Ural-western Siberia, which strongly links to Indian Ocean SSTA. Anomalous land warming over Eurasia also provides important precursors for the two modes. The cross-validated hindcast results demonstrate these modes can be predicted with significant correlation skills, suggesting that they may be considered as predictable modes. The domain averaged temporal correlation coefficient (TCC) skill during 1979 to 2015 using 0-month (1-month) lead models is 0.39 (0.35), which is considerably higher than dynamical models' multi-model ensemble mean skill (-0.02). Maximum potential attainable prediction skills are also estimated and discussed. The result illustrates advantage of PMA in predicting rainfall over dry land areas and large room for dynamical model improvement. However, secular changes of predictors need to be detected continuously in order to make practical useful prediction.

  1. Correlation and causation in tree-ring-based reconstruction of paleohydrology in cold semiarid regions

    NASA Astrophysics Data System (ADS)

    Elshorbagy, Amin; Wagener, Thorsten; Razavi, Saman; Sauchyn, David

    2016-09-01

    This paper discusses ways in which the tree-ring-based reconstruction of paleohydrology can be better understood and better utilized to support water resource management, especially in cold semiarid regions. The relationships between tree growth as represented by tree ring chronologies (TRCs), runoff (Q), precipitation (P), and evapotranspiration (ET) are discussed and analyzed within both statistical and hydrological contexts. Data from the Oldman River Basin (OMRB), Alberta, Canada, are used to demonstrate the relevant issues. Instrumental records of Q and P data were available while actual ET was estimated using a lumped conceptual hydrological model developed in this study. Correlation analysis was conducted to explore the relationships between TRCs and each of Q, P, and ET over the entire historical record (globally) as well as locally in time within the wet and dry subperiods. Global and local correlation strengths and linear relationships appear to be substantially different. This outcome particularly affects tree-ring-based inferences about the hydrology of wet and dry episodes when reconstructions are made using regression models. Important findings include (i) reconstruction of paleo-runoff may not be as credible as paleo-precipitation and paleo-evapotranspiration; (ii) a moving average window of P and ET larger than 1 year might be necessary for reconstruction of these variables; and (iii) the long-term mean of reconstructed P, Q, and ET leads us to conclude that there is uncertainty about the past climate. Finally, we suggest using the topographic index to prejudge side suitability for dendrohydrological analysis.

  2. Annual variation of (7)Be soil inventory in a semiarid region of central Argentina.

    PubMed

    Lohaiza, F; Velasco, H; Juri Ayub, J; Rizzotto, M; Di Gregorio, D E; Huck, H; Valladares, D L

    2014-04-01

    Reliable information on environmental radionuclides atmospheric entrance, and their distribution along the soil profile, is a necessary condition for using these soil and sediment tracers to investigate key environmental processes. To address this need, (7)Be content in rainwater and the wet deposition in a semiarid region at San Luis Province, Argentina, were studied. Following these researches, in the same region, we have assessed the (7)Be content along a soil profile, during 2.5 years from September 2009 to January 2012. As expected, the specific activity values in soil samples in the wet period (November-April) were higher than in the dry period (May-October). During the investigated period (2009 - beginning 2012) and for all sampled points, the maximum value of the (7)Be specific activity (Bq kg(-1)) was measured at the surface level. A typical decreasing exponential function of (7)Be areal activity (Bq m(-2)) with soil mass depth (kg m(-2)) was found and the key distribution parameters were determined for each month. The minimum value of areal activity was 51 Bq m(-2) in August, and the maximum was 438 Bq m(-2) in February. The relaxation mass depth ranges from 2.9 kg m(-2) in March to 1.3 kg m(-2) in August. (7)Be wet deposition can explain in a very significant proportion the (7)Be inventory in soil. During the period of winds in the region (September and October), the (7)Be content in soil was greater than the expected contribution from wet deposition, situation that is compatible with a higher relative contribution of dry deposition at this period of the year.

  3. Regional Cost Estimates for Reclamation Practices on Arid and Semiarid Lands

    SciTech Connect

    W. K. Ostler

    2002-02-01

    The U.S. Army uses the Integrated Training Area Management program for managing training land. One of the major objectives of the Integrated Training Area Management program has been to develop a method for estimating training land carrying capacity in a sustainable manner. The Army Training and Testing Area Carrying Capacity methodology measures training load in terms of Maneuver Impact Miles. One Maneuver Impact Mile is the equivalent impact of an M1A2 tank traveling one mile while participating in an armor battalion field training exercise. The Army Training and Testing Area Carrying Capacity methodology is also designed to predict land maintenance costs in terms of dollars per Maneuver Impact Mile. The overall cost factor is calculated using the historical cost of land maintenance practices and the effectiveness of controlling erosion. Because land maintenance costs and effectiveness are influenced by the characteristics of the land, Army Training and Testing Area Carrying Capacity cost factors must be developed for each ecological region of the country. Costs for land maintenance activities are presented here for the semiarid and arid regions of the United States. Five ecoregions are recognized, and average values for reclamation activities are presented. Because there are many variables that can influence costs, ranges for reclamation activities are also presented. Costs are broken down into six major categories: seedbed preparation, fertilization, seeding, planting, mulching, and supplemental erosion control. Costs for most land reclamation practices and materials varied widely within and between ecological provinces. Although regional cost patterns were evident for some practices, the patterns were not consistent between practices. For the purpose of estimating land reclamation costs for the Army Training and Testing Area Carrying Capacity methodology, it may be desirable to use the ''Combined Average'' of all provinces found in the last row of each table

  4. Holocene semi-arid oak woodlands in the Irano-Anatolian region of Southwest Asia: natural or anthropogenic?

    NASA Astrophysics Data System (ADS)

    Asouti, Eleni; Kabukcu, Ceren

    2014-04-01

    It is commonly accepted that, following the end of the Pleistocene, semi-arid deciduous oak woodlands did not spread in the Irano-Anatolian region of Southwest Asia as quickly as they did in the Levantine Mediterranean littoral, despite the fact that climatic improvement occurred broadly at the same time in both regions. Prehistoric impacts on woodland vegetation (such as woodcutting, burning and clearance for cultivation), the harsh continental climate of inland Southwest Asia and its distance from late Pleistocene arboreal refugia have all been discussed in the literature as likely causes of the delay. In this paper we argue that semi-arid deciduous oak woodlands should not be viewed as part of the “natural” vegetation of the Irano-Anatolian region that has been progressively destroyed by millennia of human activities since the Neolithic. They represent instead one of the earliest anthropogenic vegetation types in Southwest Asia, one that owes its very existence to prehistoric landscape practices other scholars commonly label as “destructive”. Drawing on anthracological, pollen and modern vegetation data from central Anatolia we describe how the post-Pleistocene species-rich and structurally diverse temperate semi-arid savanna grasslands were gradually substituted by low-diversity, even-aged Quercus-dominated parklands and wood pastures in the course of the early Holocene. Economic strategies that encouraged the establishment and spread of deciduous oaks included sheep herding that impacted on grass and forb vegetation, the controlling of competing arboreal vegetation through woodcutting, and woodland management practices such as coppicing, pollarding and shredding that enhanced Quercus vegetative propagation, crown and stem growth. Understanding the origin and evolution of the Irano-Anatolian semi-arid oak woodlands of Southwest Asia is of critical importance for reconstructing the changing ecologies and geographical distributions of the progenitors of

  5. Monitoring small reservoirs in semi-arid region by satellite SAR data

    NASA Astrophysics Data System (ADS)

    Nicolina Papa, Maria; Mitidieri, Francesco; Amitrano, Donato; Ruello, Giuseppe; Di Martino, Gerardo; Iodice, Antonio; Riccio, Daniele

    2016-04-01

    The work presents a novel tool for the monitoring of small reservoirs in semi-arid regions. The pilot project was developed in the Yatenga region, a Sahelian area in northern Burkina Faso. In semi-arid regions, small reservoirs are widely employed for facing seasonal variability in water availability due to the alternation of a rainy (3 months) and a dry (9 months) season. Beside their crucial importance, the small reservoirs are not appropriately monitored, they are often built for the initiative of small local communities and even basic data as their location and capacity are not available. Another major problem is linked to soil erosion due to water and consequent reservoirs' sedimentation that reduces the amount of available water and the life span of reservoirs. This lack of data prevents the implementation of strategies for the optimization of water resources management. It is therefore necessary to improve the data availability through the development of cost-effective monitoring techniques and to adapt the hydrological modeling to the limited available data. In this context the use if satellite data can highly contribute to the achievement of crucial information at low costs, high resolution in time and wide areas. In the present work, we used COSMO-SkyMed Stripmap (3m resolution) and Spotligth (1m resolution) Synthetic Aperture Radar (SAR) data acquired under the aegis of the 2007 Italian Space Agency Announcement of Opportunity and of the HydroCIDOT project. The shorelines of the reservoirs were extracted from the series of SAR images by employing an innovative change-detection framework. A digital elevation model (DEM) of the study area was obtained via standard interferometry processing of images acquired at the end of the dry season, when small reservoirs are completely empty, and information about the surface usually covered by water can be retrieved. The obtained DEM and shorelines were used for bathymetry extraction of reservoirs. For the

  6. Groundwater recharge estimation in semi-arid zone: a study case from the region of Djelfa (Algeria)

    NASA Astrophysics Data System (ADS)

    Ali Rahmani, S. E.; Chibane, Brahim; Boucefiène, Abdelkader

    2016-03-01

    Deficiency of surface water resources in semi-arid area makes the groundwater the most preferred resource to assure population increased needs. In this research we are going to quantify the rate of groundwater recharge using new hybrid model tack in interest the annual rainfall and the average annual temperature and the geological characteristics of the area. This hybrid model was tested and calibrated using a chemical tracer method called Chloride mass balance method (CMB). This hybrid model is a combination between general hydrogeological model and a hydrological model. We have tested this model in an aquifer complex in the region of Djelfa (Algeria). Performance of this model was verified by five criteria [Nash, mean absolute error (MAE), Root mean square error (RMSE), the coefficient of determination and the arithmetic mean error (AME)]. These new approximations facilitate the groundwater management in semi-arid areas; this model is a perfection and amelioration of the model developed by Chibane et al. This model gives a very interesting result, with low uncertainty. A new recharge class diagram was established by our model to get rapidly and quickly the groundwater recharge value for any area in semi-arid region, using temperature and rainfall.

  7. Genesis and Clay Mineralogical Investigation of Highly Calcareous Soils in Semi-Arid Regions of Southern Iran

    NASA Astrophysics Data System (ADS)

    Emadi, Mostafa; Baghernejad, Majid; Memarian, Hamidreza; Saffari, Mahboub; Fathi, Hamed

    This study outlines principal characteristics of soils occurred in the arid and semi-arid regions of Southern Iran. An outstanding characteristic of these soils is a prominent horizon of calcium carbonate accumulation at or near the depths of rainfall penetration. Objectives of this study were to discuss the genesis, morphological and physico-chemical properties of calcic horizons and mineralogy and classification of soils in semi-arid region. Five representative profiles were selected and soil samples were collected to determine the chemical and physical properties. Carbonate accumulation and clay eluviation-illuviation are the dominant processes in these soils. Calcium carbonate in the studied soils varied from continuous coatings with weakly cemented matrix which appears as few to common carbonate nodules (stage II) and to plugged horizon (stage III). Palygorskite, chlorite, illite, smectite and vermiculite minerals were observed in soil samples. Illite and chlorite are largely inherited from parent materials. Inheritance, transformation and neoformation from other minerals are the main pathways for the occurrence of smectite and palygorskite in the studied soils. Presence of kaolinite only in deeper calcic horizons suggested that these horizons developed in a tropical climate that shifted gradually towards semi-arid conditions. The soils of study site were classified as Typic Calcixerepts, Petrocalcic Calcixerepts and Calcic Haploxeralfs, respectively.

  8. Attribution analysis of runoff decline in a semiarid region of the Loess Plateau, China

    NASA Astrophysics Data System (ADS)

    Li, Binquan; Liang, Zhongmin; Zhang, Jianyun; Wang, Guoqing; Zhao, Weimin; Zhang, Hongyue; Wang, Jun; Hu, Yiming

    2016-12-01

    runoff decline. This study enhances our understanding of runoff changes caused by SWC measures and climate variability in the typical semiarid region of Loess Plateau, China.

  9. Chemical and isotopic methods for quantifying ground-water recharge in a regional, semiarid environment

    USGS Publications Warehouse

    Wood, Warren W.; Sanford, Ward E.

    1995-01-01

    The High Plains aquifer underlying the semiarid Southern High Plains of Texas and New Mexico, USA was used to illustrate solute and isotopic methods for evaluating recharge fluxes, runoff, and spatial and temporal distribution of recharge. The chloride mass-balance method can provide, under certain conditions, a time-integrated technique for evaluation of recharge flux to regional aquifers that is independent of physical parameters. Applying this method to the High Plains aquifer of the Southern High Plains suggests that recharge flux is approximately 2% of precipitation, or approximately 11 ± 2 mm/y, consistent with previous estimates based on a variety of physically based measurements. The method is useful because long-term average precipitation and chloride concentrations in rain and ground water have less uncertainty and are generally less expensive to acquire than physically based parameters commonly used in analyzing recharge. Spatial and temporal distribution of recharge was evaluated by use of δ2H, δ18O, and tritium concentrations in both ground water and the unsaturated zone. Analyses suggest that nearly half of the recharge to the Southern High Plains occurs as piston flow through playa basin floors that occupy approximately 6% of the area, and that macropore recharge may be important in the remaining recharge. Tritium and chloride concentrations in the unsaturated zone were used in a new equation developed to quantify runoff. Using this equation and data from a representative basin, runoff was found to be 24 ± 3 mm/y; that is in close agreement with values obtained from water-balance measurements on experimental watersheds in the area. Such geochemical estimates are possible because tritium is used to calculate a recharge flux that is independent of precipitation and runoff, whereas recharge flux based on chloride concentration in the unsaturated zone is dependent upon the amount of runoff. The difference between these two estimates yields the amount

  10. [Progress in spectral characteristics of biological soil crust of arid or semiarid region].

    PubMed

    Fang, Shi-bo; Liu, Hua-jie; Zhang, Xin-shi; Dong, Ming; Liu, Jian-dong

    2008-08-01

    The Biological Soil Crusts (BSC) (also known as organic or microphytic crust) can be formed by different combinations of microphytic communities including mosses, lichens, liverworts, algae, fungi, cyanobacteria (= blue-green algae or Cyanophyta), as well as bacteria. Large areas of sand fields in arid and semi-arid regions are covered by BSC. Remote sensing distinction should be made between physical and biogenical crust formations. It was reviewed the advances of domestic and overseas studies of BSC spectral characteristics, as well as spectral reflectance measurement in situ of our workgruop. When the BSC is wet, it turns green, a notable change in the reflectance curve occurs. The wet BSC's spectral reflectance curve is similar to those of the higher plants and therefore may lead to misinterpretation of the vegetation dynamics and to overestimation of ecosystem productivity. This spectral feature produces a much higher NDVI value for the wet moss BSC than for the dry moss BSC (0.65 vs. 0.30 units, respectively), a higher NDVI value for the wet algae BSC than for the dry algae BSC (0.30 vs. 0.15 units, respectively). The "maximum value composite" (MVC) technique is used to eliminate the effect of clouds and haze from vegetation maps. Misinterpretation of the vegetation dynamics could be more severe due to the MVC technique used to compose the global vegetation maps in the study of vegetation dynamics. But relatively limited research has been conducted to investigate the spectral characteristics of BSC change with different moisture conditions and under different seasons. More research works could be considered in spectral characteristics of BSC. The researches would be useful for detecing and mapping BSC, from remote sensing imagery. It also is to the advantage to employ Vegetation Index wisely.

  11. Comparing approaches for modeling spatially distributed direct recharge in a semi-arid region (Okanagan Basin, Canada)

    NASA Astrophysics Data System (ADS)

    Liggett, Jessica E.; Allen, Diana M.

    2010-03-01

    Spatially distributed recharge is compared at two different scales using three different modeling approaches within the semi-arid Okanagan Basin, British Columbia, Canada. Regional recharge was modeled by mapping results for one-dimensional soil columns from the water-balance code HELP (Hydrologic Evaluation of Landfill Performance, V3.80D). The regional model was then compared to two, independently derived, local-scale models to ensure local trends were captured in the regional model, and to compare modeling methods. Average annual recharge, predicted by the regional model, varied from no recharge to 186 mm/yr. For the north Okanagan (Vernon area), regional estimates were compared to Richards’ equation-based MIKE-SHE (V2007) estimates, which showed a significant difference in average annual recharge: 7 mm/yr (MIKE-SHE) and 109 mm/yr (HELP). In the south Okanagan (Oliver area), regional estimates were compared to high-resolution, local HELP estimates. Similar values of average annual recharge were obtained: 34 mm/yr (local) and 42 mm/yr (regional). A comparison with measured actual evapotranspiration data in the north Okanagan, showed HELP over-predicted recharge compared to MIKE-SHE by under-predicting evapotranspiration during summer months. Thus, the use of HELP in semi-arid areas may be limited if accurate estimates of recharge are needed. However, results may give satisfactory groundwater model calibrations results because of high uncertainty in hydraulic properties.

  12. A comparative study of fire weather indices in a semiarid south-eastern Europe region. Case of study: Murcia (Spain).

    PubMed

    Pérez-Sánchez, Julio; Senent-Aparicio, Javier; Díaz-Palmero, José María; Cabezas-Cerezo, Juan de Dios

    2017-03-11

    Forest fires are an important distortion in forest ecosystems, linked to their development and whose effects proceed beyond the destruction of ecosystems and material properties, especially in semiarid regions. Prevention of forest fires has to lean on indices based on available parameters that quantify fire risk ignition and spreading. The present study was conducted to compare four fire weather indices in a semiarid region of 11,314km(2) located in southern Spain, characterised as being part of the most damaged area by fire in the Iberian Peninsula. The studied period comprises 3033 wildfires in the region during 15years (2000-2014), of which 80% are >100m(2) and 14% >1000m(2), resulting around 40km(2) of burnt area in this period. The indices selected have been Angström Index, Forest Fire Drought Index, Forest Moisture Index and Fire Weather Index. Likewise, four selection methods have been applied to compare the results of the studied indices: Mahalanobis distance, percentile method, ranked percentile method and Relative Operating Characteristic curves (ROC). Angström index gives good results in the coastal areas with higher temperatures, low rainfall and wider range of variations while Fire Weather Index has better results in inland areas with higher rainfall, dense forest mass and fewer changes in meteorological conditions throughout the year. ROC space rejects all the indices except Fire Weather Index with good performance all over the region. ROC analysis ratios can be used to assess the success (or lack thereof) of fire indices; thus, it benefits operational wildfire predictions in semiarid regions similar to that of the case study.

  13. Mapping impervious surfaces using object-oriented classification in a semiarid urban region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mapping the expansion of impervious surfaces in urbanizing areas is important for monitoring and understanding the hydrologic impacts of land development. The most common approach using spectral vegetation indices, however, is difficult in arid and semiarid environments where vegetation is sparse an...

  14. Ecosystem Services and Reallocation Choices: A Framework for Preserving Semi-Arid Regions in the Southwest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation of freshwater systems is a paramount issue in the semi-arid Southwestern U.S. Over time, these systems have been degraded by anthropogenic activities and, more recently, are threatened by climate change. For water reallocation efforts to succeed in preserving these systems, a policy mak...

  15. Commonalities of carbon dioxide exchange in semiarid regions with monsoon and Mediterranean climates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Semiarid ecosystems with monsoon climates receive precipitation during the warm season while Mediterranean systems are characteristically wet in the cool season and dry in the summer. Comparing biosphere-atmosphere carbon exchange across these two climate regimes can yield information about the int...

  16. Greenhouse Gas Emissions in the Brazilian Semiarid Region: Environmental, Climate and Social Constraints

    NASA Astrophysics Data System (ADS)

    Sousa Neto, E. R.; Ometto, J. P.; Aguiar, A. P. D.; Mata, M. V.

    2014-12-01

    Removing a forest to open new agricultural lands, which has been very intensive in countries like Brazil during the last decades, contributes to about 12% of the global anthropogenic emissions. Forest cover removal releases carbon dioxide (CO2) and other greenhouse gases (GEE) like methane (CH4) and nitrous oxide (N2O), as a result of burning trees, followed by gradual decomposition of the forest biomass left on the ground while pasture or crop plantations are being established. In Brazil, the 2nd Brazilian National Communication to the United Nations Framework Convention on Climate Change (UNFCCC) presents the mean annual net CO2 emissions caused by changes in land use (LUC) in each Brazilian biome and the first place in the ranking is occupied by the Amazon Rainforest Biome (860,874 Gg), followed by Savannah (302,715 Gg), Atlantic Forest (79,109 Gg), Caatinga (37,628 Gg), Pantanal (16,172 Gg) and Pampa (-102 Gg) (MCT 2010). Despite these results, the estimates of CO2 emissions caused by LUC in the Brazilian semiarid region (Caatinga) are very limited and scarce, and associated to uncertainties directly related to the estimated biomass in different types of vegetation which are spatially distributed within the biome, as well as the correct representation of the dynamics of the deforestation process itself, and the more accurate mapping use and land cover. Based on such facts, this project is estimating the emissions of the main greenhouse gases (CO2, N2O and CH4) caused by land use changes in an area of Caatinga biome in Pernambuco State through the model INPE-EM. So far, it is known that from decades of 1940 up to 1995, Caatinga biome has contributed with about 3.2 % to total land use change emissions in the country, and recently (1990-2005), the contributions of Caatinga are even higher (over 30%), according to the 2nd Brazilian National Communication (2010). By means means of the model INPE-EM (data still being acquired), we are trying to diminish the

  17. Greenhouse gas emissions in the Brazilian semiarid region: environmental, climate and social constraints

    NASA Astrophysics Data System (ADS)

    Sousa-Neto, Eráclito; Ometto, Jean

    2014-05-01

    The process of removing a forest to open new agricultural lands, which has been very intensive in developing countries like Brazil during the last decades (Lapola et al, 2014), contributes to about 12% of the global anthropogenic emissions (Le Quéré et al., 2009). Forest cover removal releases carbon dioxide (CO2) and other greenhouse gases (GEE) like methane (CH4) and nitrous oxide (N2O), as a result of burning trees, followed by gradual decomposition of the forest biomass left on the ground while pasture or crop plantations are being established (Ramankutty et al., 2007). In Brazil, the 2nd Brazilian National Communication to the United Nations Framework Convention on Climate Change (UNFCCC), presents the mean annual net CO2 emissions caused by changes in land use in each Brazilian biome and the first place in the ranking is occupied by the Amazon Rainforest Biome (860,874 Gg), followed by Savannah (302,715 Gg), Atlantic Forest (79,109 Gg), Caatinga (37,628 Gg), Pantanal (16,172 Gg) and Pampa (-102 Gg) (MCT 2010). Despite these results, the estimates of CO2 emissions caused by land use changes in the Brazilian semiarid region (Caatinga) are very limited and scarce, and associated to uncertainties which are directly related to the estimated biomass in different types of vegetation which are spatially distributed within the biome, as well as the correct representation of the dynamics of the deforestation process itself, and the more accurate mapping use and land cover. Based on such facts, this project is estimating the emissions of the main greenhouse gases (CO2, N2O and CH4) caused by land use changes in an area of Caatinga biome in Pernambuco State through the model INPE-EM. So far, it is known that from decades of 1940 up to 1995, Caatinga biome has contributed with about 3.2 % to total land use change emissions in the country (Leite et al, 2012), and recently (1990-2005), the contributions of Caatinga are even higher (over 30%), according to the 2nd

  18. Quantifying Uncertainty in Distributed Flash Flood Forecasting for a Semiarid Region

    NASA Astrophysics Data System (ADS)

    Samadi, S.; Pourreza Bilondi, M.; Ghahraman, B.; Akhoond-Ali, A. M.

    2015-12-01

    Reliability of semiarid flood forecasting is affected by several factors, including rainfall forcing, the system input-state-output behavior, initial soil moisture conditions and model parameters and structure. This study employed Bayesian frameworks to enable the explicit description and assessment of parameter and predictive uncertainty for convective rainfall-runoff modeling of a semiarid watershed system in Iran. We examined the performance and uncertainty analysis of a mixed conceptual and physical based rainfall-runoff model (AFFDEF) linked with three Markov chain Monte Carlo (MCMC) samplers: the DiffeRential Evolution Adaptive Metropolis (DREAM), the Shuffled Complex Evolution Metropolis (SCEM-UA), and DREAM- ZS, to forecast four potential semiarid convective events with varying rainfall duration (<24 hrs) and amount (>20 mm). Calibration results demonstrated that model predictive uncertainty was heavily dominated by error and bias in the soil water storage capacity which reflect inadequate representation of the upper soil zone processes by hydrological model. Furthermore, parameters associated with infiltration and interception capacity along with contributing area threshold for digital river network were identified the key model parameters and more influential on the modeled flood hydrograph. In addition, parameter inference in the DREAM model showed a consistent behavior with the priori assumption by closely matching the inferred error distribution to the empirical distribution of the model residual, indicating that model parameters are well identified. DREAM result further revealed that the uncertainty associated with rainfall of lower magnitudes was higher than rainfall of higher magnitudes. Uncertainty quantification of semiarid convective events provided significant insights into the mathematical relationship and characteristics of short-term forecast error and may be applicable to other semiarid watershed systems with the similar rainfall

  19. Regional extreme climate events on the northeastern Tibetan Plateau since AD 1450 inferred from tree rings

    NASA Astrophysics Data System (ADS)

    Qin, Chun; Yang, Bao; Bräuning, Achim; Sonechkin, Dmitry M.; Huang, Kai

    2011-02-01

    Qilian juniper ( Juniperus przewalskii Kom.) is a widely distributed tree species growing on south-facing slopes in the northeastern Tibetan Plateau in arid northwestern China. We established a tree-ring width network based on two new chronologies and four previously published chronologies. Correlation and response function analyses demonstrate that precipitation positively influences radial growth. Despite of minor differences in local climate-growth relations, precipitation for the annual window between previous July and current June shows consistent positive correlations with ring width at all study sites. Similar to the so called 'pointer year' approach, 'anomalous' growth years were defined to extract extreme climate events for the period AD 1450-2006. We defined a dryness-wetness grade series with five grades of climate events inferred from anomalous year analysis. During the last 50 years, the frequency of wet events increased and that of drought events decreased noticeably, implying that the probability of occurrence of dry years in the northeastern Tibetan Plateau will further decrease in the future if regional warming continues. Combining our proxy records with a historical dryness-wetness record from eastern China, we mapped dryness-wetness patterns over large parts of China. By analyzing the atmospheric pressure patterns at the 850 hPa level over China for selected extreme event years, we found that the confluence of cold and hot air is a precondition for a flood event in the northeastern Tibetan Plateau. Thus, a counter-clockwise atmospheric circulation centered in south of Lake Baikal only occurs in flood event years.

  20. Different regional climatic drivers of Holocene large wildfires in boreal forests of northeastern America

    NASA Astrophysics Data System (ADS)

    Remy, Cécile C.; Hély, Christelle; Blarquez, Olivier; Magnan, Gabriel; Bergeron, Yves; Lavoie, Martin; Ali, Adam A.

    2017-03-01

    Global warming could increase climatic instability and large wildfire activity in circumboreal regions, potentially impairing both ecosystem functioning and human health. However, links between large wildfire events and climatic and/or meteorological conditions are still poorly understood, partly because few studies have covered a wide range of past climate-fire interactions. We compared palaeofire and simulated climatic data over the last 7000 years to assess causes of large wildfire events in three coniferous boreal forest regions in north-eastern Canada. These regions span an east-west cline, from a hilly region influenced by the Atlantic Ocean currently dominated by Picea mariana and Abies balsamea to a flatter continental region dominated by Picea mariana and Pinus banksiana. The largest wildfires occurred across the entire study zone between 3000 and 1000 cal. BP. In western and central continental regions these events were triggered by increases in both the fire-season length and summer/spring temperatures, while in the eastern region close to the ocean they were likely responses to hydrological (precipitation/evapotranspiration) variability. The impact of climatic drivers on fire size varied spatially across the study zone, confirming that regional climate dynamics could modulate effects of global climate change on wildfire regimes.

  1. [Spatial variability of soil moisture, nutrients, and productivity on slopeland in loessial semiarid region].

    PubMed

    Pan, Chengzhong; Shangguan, Zhouping

    2004-11-01

    For the sustainable development and ecological construction in the loessial semiarid region, it is important to describe the variability of slopeland soil properties and the affecting factors of slopeland productivity. In this study, soil samples were taken from eroded steep slopeland, and leaf area index (LAI) and above-ground biomass (AGB) were measured at the sampling locations. The soil water content (WC) of 2 m depth at 20 cm intervals, and the soil organic matter (OM), total nitrogen (TN), total phosphorus (TP), available nitrogen (AN) and available phosphorus (AP) contents of 0-20 and 20-40 cm soil layers were determined in the laboratory. The results showed that the majority of the properties was normally distributed, and the nutrient contents were higher in 0-20 cm than in 20-40 cm layer, but the variations of soil nutrients were much smaller in 0-20 cm than in 20-40 cm layer. Soil nutrients had a significantly larger variation than soil moisture. Soil nutrient contents in 20-40 cm layer kept increasing from upslope to downslope, while those in 0-20 cm layer varied slightly. Slope topography had more obvious impact on soil organic matter, total nitrogen and available phosphorus than other affecting factors. Soil water and nutrient contents on the shallow gully trough were notably higher than those on the upslope, but above-ground biomass was less than that on the upslope. Though longitudinal slope (35 degrees-45 degrees) was obviously larger than the horizontal one (5 degrees-10 degrees), horizontal slope position had a greater influence on soil nutrients, but much weaker effect on soil moisture than longitudinal direction. There were significant correlations between 0-120 cm soil moisture and 20-40 cm soil nutrients, and among soil nutrients except 0-20 cm soil available phosphorus. Slopeland position had a great impact on soil moisture and nutrients, but soil moisture and/or nutrients had no significant impact on above-ground biomass.

  2. Reconstruction of paleohydrology in semi-arid regions for water resources management: Opportunities and challenges

    NASA Astrophysics Data System (ADS)

    Elshorbagy, Amin; Wagener, Thorsten; Razavi, Saman; Sauchyn, David

    2016-04-01

    Tree-ring based reconstruction of paleohydrology can be a valuable and important means to extend the available hydrological records for several centuries. Such record extension, when properly done, can improve water resources management and planning by making available realistic long records that reflect past short- and long-term hydrometeorological variabilities. This research highlights some of the important, and perhaps unresolved, issues in tree-ring based reconstruction of paleohydrology, especially in semi-arid regions. The relationships between tree growth, as represented by tree-ring chronologies (TRCs), runoff (Q), precipitation (P), and evapotranspiration (ET) are discussed within both statistical and hydrological contexts. The Oldman River Basin (OMRB), Alberta, Canada, is presented as a case study, with TRCs and hydrometeorological data used to demonstrate the relevant issues. Runoff and precipitation data were available through measurements, and actual evapotranspiration was estimated using a lumped conceptual hydrological model developed in this study for the OMRB. Correlation analysis was conducted to explore the relationships between TRCs and each of Q, P, and ET over the entire historical record (globally) as well as locally within the wet and dry subperiods. Global and local correlation strengths and linear relationships appear to be significantly different, particularly affecting tree-ring based inferences about the hydrology and wet and dry episodes from reconstructions made using regression models. This finding is not typically highlighted in the available literature. Reconstruction of paleoQ may also not be as credible as paleoP and paleoET. This is discussed within the context of the watershed storage and release functions. It was also found that a moving average window, of more than one year, of P and ET time series might be necessary for reconstruction of these variables using tree-ring chronologies. This study improves our understanding of

  3. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    PubMed

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating.

  4. Langley method applied in study of aerosol optical depth in the Brazilian semiarid region using 500, 670 and 870 nm bands for sun photometer calibration

    NASA Astrophysics Data System (ADS)

    Cerqueira, J. G.; Fernandez, J. H.; Hoelzemann, J. J.; Leme, N. M. P.; Sousa, C. T.

    2014-10-01

    Due to the high costs of commercial monitoring instruments, a portable sun photometer was developed at INPE/CRN laboratories, operating in four bands, with two bands in the visible spectrum and two in near infrared. The instrument calibration process is performed by applying the classical Langley method. Application of the Langley’s methodology requires a site with high optical stability during the measurements, which is usually found in high altitudes. However, far from being an ideal site, Harrison et al. (1994) report success with applying the Langley method to some data for a site in Boulder, Colorado. Recently, Liu et al. (2011) show that low elevation sites, far away from urban and industrial centers can provide a stable optical depth, similar to high altitudes. In this study we investigated the feasibility of applying the methodology in the semiarid region of northeastern Brazil, far away from pollution areas with low altitudes, for sun photometer calibration. We investigated optical depth stability using two periods of measurements in the year during dry season in austral summer. The first one was in December when the native vegetation naturally dries, losing all its leaves and the second one was in September in the middle of the dry season when the vegetation is still with leaves. The data were distributed during four days in December 2012 and four days in September 2013 totaling eleven half days of collections between mornings and afternoons and by means of fitted line to the data V0 values were found. Despite the high correlation between the collected data and the fitted line, the study showed a variation between the values of V0 greater than allowed for sun photometer calibration. The lowest V0 variation reached in this experiment with values lower than 3% for the bands 500, 670 and 870 nm are displayed in tables. The results indicate that the site needs to be better characterized with studies in more favorable periods, soon after the rainy season.

  5. Burkholderia pseudomallei Antibodies in Individuals Living in Endemic Regions in Northeastern Brazil

    PubMed Central

    Rolim, Dionne Bezerra; Vilar, Dina Cortez F. L.; de Góes Cavalcanti, Luciano Pamplona; Freitas, Liara B. N.; Inglis, Timothy J. J.; Nobre Rodrigues, Jorge Luiz; Nagao-Dias, Aparecida Tiemi

    2011-01-01

    A seroepidemiological investigation was conducted among the population of two municipalities in Northeastern Brazil. Immunoglobulin M (IgM) and IgG antibodies to Burkholderia pseudomallei were positive in 51.27% (161 in 317 samples) and 58.49% (186), respectively. IgM titers were higher in children than in adults. On the contrary, IgG increased progressively with age. We observed a significant association between agricultural occupation and raised IgM titers (P < 0.005) and IgG titers (P < 0.001), and between construction workers and raised IgG titers (P = 0.005). Antibody IgG avidities did not correlate with age. The highest titers of antibodies (1/800) showed the highest antibody avidity indexes (P < 0.01). Most of the serum samples recognized 45-kDa and 200-kDa bands by IgG1 and IgG2 subclasses. Our study showed a high seropositivity among individuals living in endemic regions of the state of Ceará, and highlights the need for further surveillance close to water courses such as dams and rivers in Northeastern Brazil. PMID:21292903

  6. Regional patterns of mercury content in snowpack, sphagnum, and fish in northeastern North America

    SciTech Connect

    Haines, T.; Mower, B.; Perry, R.

    1995-12-31

    High levels of mercury have been found in fish from lakes throughout the northeastern US and eastern Canada, in waters with no known local mercury source. If this mercury originates from anthropogenic emissions to the atmosphere, deposition should be higher near population centers or other point sources. The authors surveyed the mercury content of late-season snowpack, sphagnum moss, and fish at locations from southwestern Connecticut to northern Newfoundland to determine if such a pattern existed. Mercury in snow ranged 1.5 to 20 ng/L, and in sphagnum < 24 to 289 ng/g dry wt. Concentrations were generally highest at southwestern sites and lowest at northeastern sites with some exceptions. The highest concentrations in both media were at locations in Rhode Island and New Hampshire, and may reflect local source emissions. Excluding these sites, the range in concentration from south to north is only a factor of two or three. These values are similar to those reported in other areas and reflect the long atmospheric residence time of gaseous elemental mercury. Mercury concentration in fish ranged 0.1 to 1.0 ug/g wet wt. and showed no regional pattern. Rather, fish mercury concentration was affected by fish species and size, being highest in large predatory species such as smallmouth bass (Micropterus dolomieu), and lowest in small nonpredatory species such as yellow perch (Perca flavescens) and brook trout (Salvelinus fontinalis).

  7. Morphology and Chemical composition of Atmospheric Particles over Semi-Arid region (Jaipur, Rajasthan) of India

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Agnihotri, R.; Yadav, P.; Singh, S.; Tawale, J. S.; Rashmi, R.; Prasad, M.; Arya, B. C.; Mishra, N.

    2012-12-01

    Uncertainties associated with the radiative forcing of atmospheric dust particles is highest, owing to lack of region-specific dust morphology (particle shape, size) and mineralogy (chemical composition) database, needed for modeling their optical properties (Mishra and Tripathi, 2008). To fill this gap for the Indian region, we collected atmospheric particles (with aerodynamic size <5um, PM5 and a few bulk particles; TSP) from seven sites of Jaipur and nearby locales (semi-arid region, in the vicinity of Thar Desert of Rajasthan) at varying altitude, during late winters of ca. 2012. PM5 particles were collected on Teflon filters (for bulk chemical analyses), while pure Tin substrates (~1×1 mm2) were used for investigating individual particle morphology. Using Scanning Electron Microscope equipped with Energy Dispersive X ray (SEM-EDX) facility at NPL, images of individual particles were recorded and the morphological parameters (e.g. Aspect ratio; AR, Circulatory parameter; CIR.) were retrieved following Okada et al. (2001), whereas chemical compositions of individual particles were determined by EDX and bulk samples by X ray fluorescence (XRF). The geometrical size distributions of atmospheric particles were generated for each site. Based on NIST (National Institute of Standard and Technology, USA) morphology database, the site-specific individual particle shapes reveal predominance of "Layered" (calcite and quartz rich), "Angular" structures (quartz rich) and "Flattened" particles over all the sites. Particles were found to be highly non-spherical with irregular shapes (CIR varying from 1 to 0.22 with median value ~0.76; AR varying from 1 to 5.4 with median value ~1.64). Noteworthy to mention, that unit values of AR and CIR represent spherical particles. Chemical analyses of PM5 particles revealed dominance of crustal elements e.g. Si, Al, Fe, Ca, Mg, in general. Particles over Kukas Hill (27.027° N, 75.919° E; ~800 MAGL) showed highest Fe mass fractions (~43

  8. a Proposed New Vegetation Index, the Total Ratio Vegetation Index (trvi), for Arid and Semi-Arid Regions

    NASA Astrophysics Data System (ADS)

    Fadaei, H.; Suzuki, R.; Sakai, T.; Torii, K.

    2012-07-01

    Vegetation indices that provide important key to predict amount vegetation in forest such as percentage vegetation cover, aboveground biomass, and leaf-area index. Arid and semi-arid areas are not exempt of this rule. Arid and semi-arid areas of northeast Iran cover about 3.4 million ha and are populated by two main tree species, the broadleaf Pistacia vera (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environmentally important but also genetically essential as seed sources for pistachio production in orchards. We investigated the relationships between tree density and vegetation indices in the arid and semi-arid regions in the northeast of Iran by analysing Advanced Land Observing Satellite (ALOS) data PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, and has one band with a wavelength of 0.52-0.77 μm (JAXA EORC). AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, and has four multispectral bands: blue (0.42-0.50 μm), green (0.52-0.60 μm), red (0.61-0.69 μm), and near infrared (0.76-0.89 μm) (JAXA EORC). In this study, we estimated various vegetation indices using maximum filtering algorithm (5×5) and examined. This study carried out of juniper forests and natural pistachio stand using Advanced Land Observing Satellite (ALOS) and field inventories. Have been compared linear regression model of vegetation indices and proposed new vegetation index for arid and semi-arid regions. Also, we estimated the densities of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. We present a new vegetation index for arid and semi-arid regions with sparse forest cover, the Total Ratio Vegetation Index (TRVI), and we investigate the relationship of the new index to tree density by analysing data from the

  9. Modeling the Surface Water-Groundwater Interaction in Arid and Semi-Arid Regions Impacted by Agricultural Activities

    NASA Astrophysics Data System (ADS)

    Tian, Y.; Wu, B.; Zheng, Y.

    2013-12-01

    In many semi-arid and arid regions, interaction between surface water and groundwater plays an important role in the eco-hydrological system. The interaction is often complicated by agricultural activities such as surface water diversion, groundwater pumping, and irrigation. In existing surface water-groundwater integrated models, simulation of the interaction is often simplified, which could introduce significant simulation uncertainty under certain circumstance. In this study, GSFLOW, a USGS model coupling PRMS and MODFLOW, was improved to better characterize the surface water-groundwater interaction. The practices of water diversion from rivers, groundwater pumping and irrigation are explicitly simulated. In addition, the original kinematic wave routing method was replaced by a dynamic wave routing method. The improved model was then applied in Zhangye Basin (the midstream part of Heihe River Baisn), China, where the famous 'Silk Road' came through. It is a typical semi-arid region of the western China, with extensive agriculture in its oasis. The model was established and calibrated using the data in 2000-2008. A series of numerical experiments were conducted to evaluate the effect of those improvements. It has been demonstrated that with the improvements, the observed streamflow and groundwater level were better reproduced by the model. The improvements have a significant impact on the simulation of multiple fluxes associated with the interaction, such as groundwater discharge, riverbed seepage, infiltration, etc. Human activities were proved to be key elements of the water cycle in the study area. The study results have important implications to the water resources modeling and management in semi-arid and arid basins.

  10. Satellite observation of aerosol - cloud interactions over semi-arid and arid land regions

    NASA Astrophysics Data System (ADS)

    Klüser, L.; Holzer-Popp, T.

    2012-04-01

    Satellite observations from three different sources are used to study the interactions between aerosol and ice clouds in five semi-arid and arid land regions over Africa and Asia, reaching from the South-African Kalahari to the Taklimakan and Gobi in Mongolia. (1) Six years of Aqua MODIS cloud and aerosol observations (including "Deep Blue" retrievals) which contain a qualitative separation into coarse and fine mode aerosol are analysed. (2) Five years of APOLLO cloud observations and SYNAER aerosol retrievals which allow discriminating between mineral dust and soot dominated cases from AATSR and SCIAMACHY on ENVISAT are exploited. (3) Moreover IASI provides one year of ice cloud and mineral dust observations over land retrieved with a newly developed method based on singular vector decomposition. Cloud top temperature observations are used to asses the state of convection and to statistically re-project observation distributions of cloud properties to background conditions. Then the difference between observation density distributions of background and re-projected aerosol-contaminated samples can be evaluated. By such way of analysis the influence of different cloud development stages, which also manifest in seasonal cycles of cloud properties, can be minimised. The analysis of the various observation density distributions shows that liquid water and ice effective radius is mainly decreased for increased total aerosol content for both aerosol types, biomass burning aerosols and mineral dust, separately. Two different modes of aerosol impacts on cloud optical depth can be shown. Optical depth is mainly increased, directly following the theory of the so-called "Twomey effect". In the West African Sahel a decrease of cloud water path (for both liquid water and ice) under the influence of absorbing aerosols results also in decreased optical depth. As at the same time the cloud fraction does not decrease under aerosol influence, the statistical decrease of mean

  11. Agate mineralization in basaltoids of the northeastern Ladoga region, South Karelia

    NASA Astrophysics Data System (ADS)

    Polekhovsky, Yu. S.; Punin, Yu. O.

    2008-12-01

    In the northeastern Ladoga region, the Riphean agate-bearing volcanic rocks of the Priozersk Formation are composed of basaltic lavas and lava breccias. Agates occur in the upper lava flow and in overlying conglomerate of the Salmi Formation. By their patterns, the agate amygdules correspond to concentrically zoned varieties, while agate veinlets have a vague pattern. Microstructures of agates are diverse, We backspace we including quite peculiar ones. Agates with enveloping zoning (the main structural type) were formed in closed cavities, whereas agate veinlets usually occurred in open connecting fissures and were replaced by calcite at the late stage of mineral formation. The unusual absence of quartzine suggests a low SiO2 concentration in the agate-forming solutions and/or a low pH value.

  12. Strategies for genetic study of hearing loss in the Brazilian northeastern region

    PubMed Central

    Melo, Uirá S; Santos, Silvana; Cavalcanti, Hannalice G; Andrade, Wagner T; Dantas, Vitor G; Rosa, Marine RD; Mingroni-Netto, Regina C

    2014-01-01

    The overall aim of this study was to estimate the contribution of genetic factors to the etiology of hearing loss (HL) in two counties in the Brazilian northeastern region. A cross-sectional study, based on the key informant approach (KI) was conducted in Queimadas and Gado Bravo counties (Paraíba, Northeast Brazil). The sample consisted of 182 patients with HL. Genetic screening of the most frequent mutations associated with HL was performed for all samples. DFNB1 mutations were the most frequently found in both counties. The c.35delG mutation was detected in homozygosis in seven non-syndromic probands in Queimadas (7/76, 9.2%) and only a single homozygote with this mutation was found in Gado Bravo (1/44, 2.3%). We also detected the del(GJB6-D13S1854) mutation in non-syndromic probands from Gado Bravo (2/44, 4.5%). The c.189C>A (p.TyrY63*) mutation in the CLRN1 gene was detected in homozygosis in 21/23 Usher syndrome patients from Gado Bravo and it was not found in Queimadas. Cases with probable genetic etiology contributed approximately to half of HL probands in each county (54.6% in Gado Bravo and 45.7% in Queimadas). We confirm the importance of DFNB1 locus to non-syndromic HL but we show that the frequency of mutations in the northeastern region differs somewhat from those reported in southeastern Brazil and other populations. In addition, the extremely high frequency of individuals with Usher syndrome with c.189C>A variation in CLRN1 indicates the need for a specific screening of this mutation. PMID:24596593

  13. Climate-Vegetation Interactions over Arid and Semi-Arid Regions: A Multi-Scale Causality Analysis

    NASA Astrophysics Data System (ADS)

    Molini, A.; Casagrande, E.

    2014-12-01

    This talk explores the mechanisms underlying global-scale feedbacks of vegetation on climate, with a special focus on arid and transitional (semi-arid) regions and cross-scale interactions. Whether precipitation and temperature are known to be two of the major drivers of ecosystem dynamics, the inference of the forcing of vegetation on climate from observed data still leads to extremely contradictory results. This is mainly due to the intrinsic complex and nonlinear nature of climate-vegetation interactions, which is exerted over a wide range of space, temporal and frequency scales. Beside, traditional statistical tools applied to these feedbacks rely on linear correlation measures that can hardly distinguish the different components of these interactions. We analyze monthly and sub-monthly globally gridded data of precipitation, temperature and NDVI (from both MODIS and AVHRR) by using an ensemble of different directional coupling statistics, and spectral metrics able to resolve cross-scale interactions. Based on the concept of Granger causality, we assess the bi-directional causal influences between precipitation, temperature and NDVI. In particular, we focus on spectral causality measures, in order to infer sub-processes acting across different time and frequency scales. Several examples from arid and semi-arid regions are introduced and examined. During the discussion of the result, we highlight the strength and weakness of the approach, also in the occurrence of nonlinear couplings.

  14. Climate, water management, and land use: Estimating potential potato and corn production in the U.S. northeastern seaboard region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential production capacity of the United States Northeastern Seaboard Region (NESR) was assessed using corn and potato as representative commodities. Geospatial data regarding historical climate, land use, soils, and management were coupled with a weather generator, the crop models SPUDSIM a...

  15. Assessment of desertification risk in semi-arid Mediterranean environments: the case study of Apulia region (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Ladisa, Gaetano; Todorovic, Mladen; Trisorio Liuzzi, Giuliana

    2010-05-01

    This work focuses on the risk assessment of the areas threatened with desertification in the semi-arid Mediterranean environments. The presented approach uses as a reference the ESAs model (Environmental Sensitive Areas to Desertification; Kosmas et al., 1999) which is modified through a set of new indicators which take into account the region-specific environmental characteristics as well as identifiable parameters relevant for planning control measures. These supplementary indicators, comprehending socio-economic and environmental factors, are integrated in the ESAs model and, by using a GIS, applied to Apulia region (Southern Italy). This area represents a typical Mediterranean landscape affected by land degradation and desertification risks. The analyses include the elaboration of the whole set of indices on both the regional and the administrative scales which constitute the principal territorial units for the management of natural resources. The results have demonstrated that the introduction of the new indices has improved substantially the overall evaluation of the desertification risk in the Apulia region. The proposed approach permits not only the identification and refinement of different degrees of sensibility of an area to land degradation, but also the analyses of the factors affecting desertification and their evaluation in terms of spatial and temporal distribution. Moreover, the presented method is conceptually very simple and easy to implement from local to regional and national scale, and can be proposed as a methodology for the definition of priorities in adoption of strategies to mitigate desertification in the semi-arid Mediterranean environments. Key words: desertification risk, sensitivity areas, Apulia region, Mediterranean environment.

  16. Meteorological operational services for civil protection in Veneto region (North-eastern Italy).

    NASA Astrophysics Data System (ADS)

    Barbi, A.; Monai, M.; Zardini, F.

    2009-09-01

    The Meteorological Centre of Teolo (CMT), part of the Regional Agency for Environmental Prevention and Protection of the North-eastern Italian region Veneto (ARPAV), is the operational regional meteorological service. Since April 2009 the Centre is linked to and supplies meteorological monitoring and forecasting to the recently constituted Functional Centre of the regional civil protection (CFD Veneto), which operates in the framework of National Civil Protection. The CFD Veneto supplies a multi-disciplinary, technical-scientific support to civil protection activities, to early warnings of natural hazards, in particular related to hydrogeological, hydraulic, and avalanches risks. The north-eastern part of Italy is known to be one of the rainiest regions in Europe. The region Veneto, due to its topographic configuration which includes Alpine reliefs, plans and a coast exposed to the Adriatic Sea, is conducive to heavy and long-lasting precipitation events. Also, strong thunderstorm activity with high precipitation rates, hail, wind gusts, and even tornadoes are relatively frequent occurrences. In this contribution two recent examples of different types of extreme events are briefly analysed by means of the ARPAV multi-sensor observing system which includes weather radar and a dense surface network. We show some of the impacts of such weather events on the territory, the services provided by CFD Veneto, in terms of meteorological forecasting and nowcasting products, and hydrogeologic/hydraulic hazard bullettins. The analysis highlights the difficulty of an efficient wheather forecast for civil defence purposes in a complex situation as ours, where many types of different events are possible. Especially cases of rapid convective events with their intense and very localized phenomena are a significant challenge. It is well-known that such events can bring remarkable material damages and serious danger for the people. For this reason an effective warning system which

  17. Representing Green Infrastructure Management Techniques in Arid and Semi-arid Regions: Software Implementation and Demonstration using the AGWA/KINEROS2 Watershed Model

    EPA Science Inventory

    Increasing urban development in the arid and semi-arid regions of the southwestern United States has led to greater demand for water from a region of limited water resources which has fundamentally altered the hydrologic response of developed watersheds. Green Infrastructure (GI)...

  18. Green Infrastructure Management Techniques in Arid and Semi-arid Regions: Software Implementation and Demonstration using the AGWA/KINEROS2 Watershed Model

    EPA Science Inventory

    Increasing urban development in the arid and semi-arid regions of the southwestern United States has led to greater demand for water in a region with limited water resources and has fundamentally altered the hydrologic response of developed watersheds. Green Infrastructure (GI) p...

  19. Population structure and reproductive period of two introduced fish species in a Brazilian semiarid region reservoir.

    PubMed

    Sousa, Marla Melise de Oliveira; Lopes, Suzany Iasnaya Moreira; da Costa, Rodrigo Silva; Novaes, José Luís Costa

    2015-09-01

    The Amazonian fish species Plagioscion squamosissimus (Sciaenidae) and Cichla monoculus Cichlidae), have been widely introduced into different reservoirs in Brazil, and have caused many negative mpacts on local fish fauna. The aim of this study was to evaluate the population structure (abundance, length structure, length-weight relationship, sex ratio, and length at first maturity) and the reprodutive period of these wo species in the Santa Cruz Reservoir (built in 2002), located in the Brazilian semiarid region, for their adequate management and local species conservation policies. Specimens were collected quarterly in eight sites from February 2010 to November 2013 using gillnets (12 to 70 mm mesh between adjacent knots). The specimens captured were counted and the following biometric and biological data were analysed: standard length, total weight, and reproductive data, such as, sex, weight and gonadal maturity stage. The species abundances were estimated by CPUE and expressed as the number of individuals per gill net area x gill net exposition time (m2 x h); length frequency histograms were built with intervals of 5 cm. The length-weight parameters were estimated with a linear regression after a logarithmic transformation of the data. With the reproductive data we estimated sex ratio, reproduction period and length at first maturity (L50). We captured a total of 1,071 specimens of P. squamosissimus and 156 specimens of C. monoculus. Both species showed higher abundances in 2010, 0.004306 m2 x h and 0.00022 m2 x h, respectively, but this parameter decreased from 2010 to 2013. Standard length ranged between 6.4 and 46.2 cm for P. squamosissimus (20.025.0 cm was the most frequent class), and 7.0 and 38.7 cm for C. monocidus (10.0-15.0 cm was the most frequent class). The length-weight relationships were described by the following equations: log10Wt = -1.8349+3.0899log10Lp and R2= 0.9795 for P. squamosissimus, and log10 Wt = -1.7944+3.0885log10Lp and Wt = 0

  20. Loxosceles niedeguidonae (Araneae, Sicariidae) a new species of brown spider from Brazilian semi-arid region

    PubMed Central

    Gonçalves-de-Andrade, Rute Maria; Bertani, Rogério; Nagahama, Roberto Hiroaki; Barbosa, Maria Fatima Ribeiro

    2012-01-01

    Abstract A new species of recluse spider, Loxosceles niedeguidonae sp. n., is described from the Parque Nacional Serra da Capivara, State of Piauí, Brazil. This is the first endemic species described from Brazilian semi-arid environment. The species is included in gaucho group of Gertsch (1967) due to its spermathecal shape and is considered close to Loxosceles chapadensis Bertani, Fukushima & Nagahama, 2010 by the unusual long male palpal tibia, a character not common for species of this group. An updated key for Loxosceles species of gaucho group is presented. PMID:22451789

  1. The genus Xestoleberis (Ostracoda: Xestoleberididae) in the Northern, Northeastern and Eastern regions of the Brazilian continental shelf.

    PubMed

    Da Luz, Nathália Carvalho; Coimbra, João Carlos

    2015-06-22

    The analysis of 359 samples from three regions of the Brazilian continental shelf (Northern, Northeastern and Eastern) resulted in the recognition of six species of the genus Xestoleberis. One of these species was already described, X. umbonata Whatley et al. 1998, four species are new and herein described, X. inesae sp. nov., X. amazonica sp. nov., X. subtriangularis sp. nov. and X. virilis sp. nov., and one was maintained in open nomenclature, Xestoleberis sp. The species X. inesae sp. nov. is widely distributed in the study area, occurring in all mentioned regions, while X. amazonica sp. nov. is restricted to the Northern region. Xestoleberis subtriangularis sp. nov., X. virilis sp. nov. and Xestoleberis sp. occur in the Northeastern and Eastern regions. Xestoleberis umbonata was recorded in this study only in the southernmost part of the Eastern region.

  2. Coupled Soil Water and Heat Transport Near the Land Surface in Arid and Semiarid Regions - Multi-Domain Modeling

    NASA Astrophysics Data System (ADS)

    Mohanty, Binayak; Yang, Zhenlei

    2016-04-01

    Understanding and simulating coupled water and heat transfer appropriately in the shallow subsurface is of vital significance for accurate prediction of soil evaporation that would improve the coupling between land surface and atmosphere, which consequently could enhance the reliability of weather as well as climate forecast. The theory of Philip and de Vries (1957), accounting for water vapor diffusion only, was considered physically incomplete and consequently extended and improved by several researchers by explicitly taking water vapor convection, dispersion or air flow into account. It is generally believed that the soil moisture is usually low in the near surface layer under highly transient field conditions, particularly in arid and semiarid regions, and that accurate characterization of water vapor transport is critical when modeling simultaneous water and heat transport in the shallow field soils. The first objective of this study is thus mainly to test existing coupled water and heat transport theories and to develop reasonable and simplified numerical models using field experimental data collected under semi-arid and arid hydro-climatic conditions. In addition, more complex multi-domain models are developed for ubiquitous heterogeneous terrestrial surfaces such as horizontal textural contrasts or structured heterogeneity including macropores (fractures, cracks, root channels, etc.). This would make coupled water and heat transfer models applicable in such non-homogeneous soils more meaningful and enhance the skill of land-atmosphere interaction models at a larger context.

  3. Hierarchical distance-based fuzzy approach to evaluate urban water supply systems in a semi-arid region.

    PubMed

    Yekta, Tahereh Sadeghi; Khazaei, Mohammad; Nabizadeh, Ramin; Mahvi, Amir Hossein; Nasseri, Simin; Yari, Ahmad Reza

    2015-01-01

    Hierarchical distance-based fuzzy multi-criteria group decision making was served as a tool to evaluate the drinking water supply systems of Qom, a semi-arid city located in central part of Iran. A list of aspects consisting of 6 criteria and 35 sub-criteria were evaluated based on a linguistic term set by five decision-makers. Four water supply alternatives including "Public desalinated distribution system", "PET Bottled Drinking Water", "Private desalinated water suppliers" and "Household desalinated water units" were assessed based on criteria and sub-criteria. Data were aggregated and normalized to apply Performance Ratings of Alternatives. Also, the Performance Ratings of Alternatives were aggregated again to achieve the Aggregate Performance Ratings. The weighted distances from ideal solution and anti-ideal solution were calculated after secondary normalization. The proximity of each alternative to the ideal solution was determined as the final step. The alternatives were ranked based on the magnitude of ideal solutions. Results showed that "Public desalinated distribution system" was the most appropriate alternative to supply the drinking needs of Qom population. Also, "PET Bottled Drinking Water" was the second acceptable option. A novel classification of alternatives to satisfy the drinking water requirements was proposed which is applicable for the other cities located in semi-arid regions of Iran. The health issues were considered as independent criterion, distinct from the environmental issues. The constraints of high-tech alternatives were also considered regarding to the level of dependency on overseas.

  4. Regional scaling of soil moisture dynamics on the semiarid grasslands of Mexico through remotely sensed vegetation indices

    NASA Astrophysics Data System (ADS)

    Carrera-Hernandez, J. J.; Mata-Martinez, A.; Huber-Sannwald, E.; Arredondo, T.

    2014-12-01

    Soil moisture dynamics for both native (Bouteloa gracilis) and introduced (Eragrostis curvula) species within the semiarid grasslands in Mexico are analyzed. The semiarid grasslands of Mexico are part of the shortgrass steppe ecosystem, which extends from the North American midwest in the north to Llanos de Ojuelos in the south, where the study site is located. Soil moisture dynamics are measured on two homogeneous fields; one dominated by the native species (Bouteloa gracilis), and another with an introduced species (Eragrostis curvula) at three different depths with high temporal resolution along with standard climatological data. These data are related to measured Leaf Area Index (LAI) and spectra at 16 different wavelengths, both of which, in turn, are related to remotely sensed imagery through different vegetation indices (NDVI, SAVI, EVI and Modified Chlorophyll Absorption Ratio Index (MCARI)) for different sensors (LANDSAT, SPOT, Pleiades) at different growth stages. To date, the MCARI exhibits a larger correlation with LAI for all sensors and growing stages for both grass species (ongoing field work will provide additional data). Regionalization of soil moisture dynamics (i.e. recharge) will be done using a numerical model of the vadose zone that will be linked to the temporal variation of MCARI. Financial support by the Mexico's CONACYT (project CB 158370) and UNAM's PAPIIT program (project IA100613) is acknowledged.

  5. Water from air: An overlooked source of moisture in arid and semiarid regions

    USGS Publications Warehouse

    McHugh, Theresa; Morrissey, Ember M; Reed, Sasha C.; Hungate, Bruce A.; Schwartz, Egbert

    2015-01-01

    Water drives the functioning of Earth’s arid and semiarid lands. Drylands can obtain water from sources other than precipitation, yet little is known about how non-rainfall water inputs influence dryland communities and their activity. In particular, water vapor adsorption – movement of atmospheric water vapor into soil when soil air is drier than the overlying air – likely occurs often in drylands, yet its effects on ecosystem processes are not known. By adding 18O-enriched water vapor to the atmosphere of a closed system, we documented the conversion of water vapor to soil liquid water across a temperature range typical of arid ecosystems. This phenomenon rapidly increased soil moisture and stimulated microbial carbon (C) cycling, and the flux of water vapor to soil had a stronger impact than temperature on microbial activity. In a semiarid grassland, we also observed that non-rainfall water inputs stimulated microbial activity and C cycling. Together these data suggest that, during rain-free periods, atmospheric moisture in drylands may significantly contribute to variation in soil water content, thereby influencing ecosystem processes. The simple physical process of adsorption of water vapor to soil particles, forming liquid water, represents an overlooked but potentially important contributor to C cycling in drylands.

  6. An AFLP estimation of the outcrossing rate of Spondias tuberosa (Anacardiaceae), an endemic species to the Brazilian semiarid region.

    PubMed

    Fernandes Santos, Carlos Antonio; de Souza Gama, Renata Natália Cândido

    2013-06-01

    The umbu tree (Spondias tuberosa) is one of the most important endemic species to the Brazilian tropical semiarid region. The umbu tree has edible fruits with a peculiar flavor that are consumed in natura or in a semi-industrialized form, such as jams, candies and juices. The majority of endemic species to Brazilian semiarid region have not been studied or sampled to form germ-plasm collections, which increases the risk of losing genetic variability of the adapted species to xerophytic conditions. The aim of this study was to estimate outcrossing rates in S. tuberosa using a multilocus mixed model in order to guide genetic resources and breeding programs of this species. DNA samples were extracted from 92 progenies of umbu trees, which were distributed among 12 families. These trees were planted by seed in 1991 in Petrolina, PE, Brazil. The experimental design was a randomized block, with a total of 42 progenies sampled in three regions. The experimental units were composed by five plants and five replications. The outcrossing rate was estimated by the multilocus model, which is available in the MLTR software, and was based on 17 polymorphic AFLP bands obtained from AAA_CTG and AAA_CTC primer combinations. The observed heterozygotes ranged from 0.147 to 0.499, with a maximum frequency estimated for the AAA_CTC 10 amplicon. The multilocus outcrossing estimation (t(m)) was 0.804 +/- 0.072, while the single-locus (t(s)) was 0.841 +/- 0.079, which suggests that S. tuberosa is predominantly an outcrossing species. The difference between t(m) and t(s) was -0.037 +/- 0.029, which indicates that biparental inbreeding was nearly absent. The mean inbreeding coefficient or fixation index (F) among maternal plants was--0.103 +/- 0.045, and the expected F was 0.108, which indicates that there was no excess of heterozygotes in the maternal population. The outcrossing estimates obtained in the present study indicate that S. tuberosa is an open-pollinated species. Biometrical

  7. A Framework Predicting Water Availability in a Rapidly Growing, Semi-Arid Region under Future Climate Change

    NASA Astrophysics Data System (ADS)

    Han, B.; Benner, S. G.; Glenn, N. F.; Lindquist, E.; Dahal, K. R.; Bolte, J.; Vache, K. B.; Flores, A. N.

    2014-12-01

    Climate change can lead to dramatic variations in hydrologic regime, affecting both surface water and groundwater supply. This effect is most significant in populated semi-arid regions where water availability are highly sensitive to climate-induced outcomes. However, predicting water availability at regional scales, while resolving some of the key internal variability and structure in semi-arid regions is difficult due to the highly non-linearity relationship between rainfall and runoff. In this study, we describe the development of a modeling framework to evaluate future water availability that captures elements of the coupled response of the biophysical system to climate change and human systems. The framework is built under the Envision multi-agent simulation tool, characterizing the spatial patterns of water demand in the semi-arid Treasure Valley area of Southwest Idaho - a rapidly developing socio-ecological system where urban growth is displacing agricultural production. The semi-conceptual HBV model, a population growth and allocation model (Target), a vegetation state and transition model (SSTM), and a statistically based fire disturbance model (SpatialAllocator) are integrated to simulate hydrology, population and land use. Six alternative scenarios are composed by combining two climate change scenarios (RCP4.5 and RCP8.5) with three population growth and allocation scenarios (Status Quo, Managed Growth, and Unconstrained Growth). Five-year calibration and validation performances are assessed with Nash-Sutcliffe efficiency. Irrigation activities are simulated using local water rights. Results show that in all scenarios, annual mean stream flow decreases as the projected rainfall increases because the projected warmer climate also enhances water losses to evapotranspiration. Seasonal maximum stream flow tends to occur earlier than in current conditions due to the earlier peak of snow melting. The aridity index and water deficit generally increase in the

  8. Salt tectonism in the Destin dome region, northeastern Gulf of Mexico

    SciTech Connect

    Macrae, G. )

    1991-03-01

    The continental margin of the northeastern Gulf of Mexico consists of a thick sequence of Mesozoic and Cenozoic sediments that have accumulated almost continuously since the Middle Jurassic in a relatively stable, slowly subsiding, tectonic environment. The distribution of Middle Jurassic (Callovian-age ) salt is widespread with an estimated minimum accumulation thickness of 760 m. Salt movement and associated listric normal growth faulting are the most significant tectonic elements affecting the structural development of the overlying sediments. Structural and stratigraphic relationships indicated by seismic reflection data suggest two phases of salt tectonism in the Destin dome region. The earliest record of movement of Middle Jurassic salt is in the Oxfordian-age Smackover interval sediments on the Mississippi-Alabama shelf. The development of expanded Smackover interval sedimentary sections is directly related to the regional basinward dip of the presalt surface and to the growth of salt pillows, or rollers, in response to sediment loading. Syndepositional listric normal growth faults occur on the seaward flanks of these salt structures. Growth of the Destin dome anticline on the Florida shelf reflects a significant late phase of salt movement from Late Cretaceous through early Cenozoic time. Differential sediment loading by thick salt updip onto the Florida shelf, is the interpreted mechanism for growth of the Destin dome anticline. The presalt basement surface appears to be a common detachment surface, or decollement, for salt movement.

  9. Interannual variability of tropical cyclone activity and regional Hadley circulation over the Northeastern Pacific

    NASA Astrophysics Data System (ADS)

    Zhang, Gan; Wang, Zhuo

    2015-04-01

    The interannual variability of the regional Hadley circulation (HC) and tropical cyclone (TC) activity over the Northeastern Pacific (NEP) was investigated. The interannual variability of the HC in the NEP hurricane season is found dominated by a mode (M1EP) regulating the strength and meridional extent of the Intertropical Convergence Zone. M1EP has a more robust correlation with NEP TC activity than the El Niño-Southern Oscillation sea surface temperature indices. The strong correlation is attributed to the impacts of M1EP on environmental conditions. In addition, the leading mode of the Atlantic HC, which has an anticorrelation with M1EP, also strongly impacts NEP TC activity. The findings, together with Zhang and Wang (2013), highlight the role of the HC in controlling the variability of TC activity as well as the interbasin connection between the NEP and the Atlantic. The regional HC is thus recommended as a useful metric to benchmark models in simulating TC activity.

  10. First regional evaluation of nuclear genetic diversity and population structure in northeastern coyotes ( Canis latrans)

    PubMed Central

    Monzón, Javier

    2014-01-01

    Previous genetic studies of eastern coyotes ( Canis latrans) are based on one of two strategies: sampling many individuals using one or very few molecular markers, or sampling very few individuals using many genomic markers. Thus, a regional analysis of genetic diversity and population structure in eastern coyotes using many samples and several molecular markers is lacking. I evaluated genetic diversity and population structure in 385 northeastern coyotes using 16 common single nucleotide polymorphisms (SNPs). A region-wide analysis of population structure revealed three primary genetic populations, but these do not correspond to the same three subdivisions inferred in a previous analysis of mitochondrial DNA sequences. More focused geographic analyses of population structure indicated that ample genetic structure occurs in coyotes from an intermediate contact zone where two range expansion fronts meet. These results demonstrate that genotyping several highly heterozygous SNPs in a large, geographically dense sample is an effective way to detect cryptic population genetic structure. The importance of SNPs in studies of population and wildlife genomics is rapidly increasing; this study adds to the growing body of recent literature that demonstrates the utility of SNPs ascertained from a model organism for evolutionary inference in closely related species. PMID:25075291

  11. First regional evaluation of nuclear genetic diversity and population structure in northeastern coyotes ( Canis latrans).

    PubMed

    Monzón, Javier

    2014-01-01

    Previous genetic studies of eastern coyotes ( Canis latrans) are based on one of two strategies: sampling many individuals using one or very few molecular markers, or sampling very few individuals using many genomic markers. Thus, a regional analysis of genetic diversity and population structure in eastern coyotes using many samples and several molecular markers is lacking. I evaluated genetic diversity and population structure in 385 northeastern coyotes using 16 common single nucleotide polymorphisms (SNPs). A region-wide analysis of population structure revealed three primary genetic populations, but these do not correspond to the same three subdivisions inferred in a previous analysis of mitochondrial DNA sequences. More focused geographic analyses of population structure indicated that ample genetic structure occurs in coyotes from an intermediate contact zone where two range expansion fronts meet. These results demonstrate that genotyping several highly heterozygous SNPs in a large, geographically dense sample is an effective way to detect cryptic population genetic structure. The importance of SNPs in studies of population and wildlife genomics is rapidly increasing; this study adds to the growing body of recent literature that demonstrates the utility of SNPs ascertained from a model organism for evolutionary inference in closely related species.

  12. Carbon dioxide and methane supersaturation in lakes of semi-humid/semi-arid region, Northeastern China

    NASA Astrophysics Data System (ADS)

    Wen, Zhidan; Song, Kaishan; Zhao, Ying; Jin, Xiuliang

    2016-08-01

    Understanding concentrations of carbon dioxide (CO2) and methane (CH4) in lakes is an important part of a comprehensive global carbon budget. We estimated data on the partial pressure of CO2 (pCO2) and CH4 (pCH4) from sampling with 95 lakes in semi-humid/semi-arid region of Northeastern China during ice-free period. Both pCO2 and pCH4 varied greatly among the study sites. p(CO2) values in these lakes ranged from 21.9 to 30,152.3 μatm (n = 403), and 91% of lakes in this survey were supersaturated with CO2. p(CH4) values ranged from 12.6 to 139,630.7 μatm with all sites in this study of CH4 sources to the atmosphere during the ice-free period. The collected urban lakes samples exhibited higher pCO2 and pCH4 than wild lakes samples. Either the mean value of p(CO2) or p(CH4) in saline waters is higher than in fresh waters. Correlation analysis implied that the partial pressure of the GHGs (CO2 and CH4) showed statistically correlations with water environment indicators like pH, dissolved organic carbon (DOC), total nitrogen (TN), total phosphorus (TP), and chlorophyll a (Chla). However, the most of the relationships showed a high degree of scatter, only pH might be used as the predictor of the gas partial pressure based on the result of this study (rpCO2 = -0.437, p < 0.01, n = 382; rpCH4 = -0.265, p < 0.01, n = 400). Furthermore, salinity could be a good predictor for p(CO2) and p(CH4) in 83 freshwater lakes in our study (rpCO2 = 0.365, rpCH4 = 0.323, p < 0.01, n = 348). The mean CO2 flux increased with the decreasing lake area size. The calculated annual areal carbon emission rate is 560.2 g C m-2 from 95 lakes in Northeastern China. We could not extrapolate carbon emission from these lakes to the boreal region or a wider scale because of the change of environmental conditions.

  13. Natural Breeding Places for Phlebotomine Sand Flies (Diptera: Psychodidae) in a Semiarid Region of Bahia State, Brazil

    PubMed Central

    Sangiorgi, Bruno; Miranda, Daniel Neves; Oliveira, Diego Ferreira; Santos, Edivaldo Passos; Gomes, Fernanda Regis; Santos, Edna Oliveira; Barral, Aldina; Miranda, José Carlos

    2012-01-01

    Few microhabitats have been previously identified as natural breeding places for phlebotomine sand flies so far, and little is known about the influence of climate variables in their density. The present study was conducted in a dry region with a semiarid climate, where visceral leishmaniasis occurs in humans and dogs. The occurrence of breeding places in specific microhabitats was investigated in soil samples collected from five houses, which were also the location used for sampling of adults. All the microhabitats sampled by our study were identified as natural breeding places due to the occurrence of immature forms of sand flies. On a weekly basis, the number of adult sand flies captured was positively correlated with the mean temperature from preceding weeks. These results, in addition to promoting an advance in the knowledge of sand flies biology, may furnish a tool for optimizing the control of the sand flies, by indicating the most suitable periods and microhabitats for the application of insecticides. PMID:22529861

  14. Natural breeding places for phlebotomine sand flies (Diptera: psychodidae) in a semiarid region of bahia state, Brazil.

    PubMed

    Sangiorgi, Bruno; Miranda, Daniel Neves; Oliveira, Diego Ferreira; Santos, Edivaldo Passos; Gomes, Fernanda Regis; Santos, Edna Oliveira; Barral, Aldina; Miranda, José Carlos

    2012-01-01

    Few microhabitats have been previously identified as natural breeding places for phlebotomine sand flies so far, and little is known about the influence of climate variables in their density. The present study was conducted in a dry region with a semiarid climate, where visceral leishmaniasis occurs in humans and dogs. The occurrence of breeding places in specific microhabitats was investigated in soil samples collected from five houses, which were also the location used for sampling of adults. All the microhabitats sampled by our study were identified as natural breeding places due to the occurrence of immature forms of sand flies. On a weekly basis, the number of adult sand flies captured was positively correlated with the mean temperature from preceding weeks. These results, in addition to promoting an advance in the knowledge of sand flies biology, may furnish a tool for optimizing the control of the sand flies, by indicating the most suitable periods and microhabitats for the application of insecticides.

  15. Influence of Agricultural Developments on Net Primary Productivity (NPP) in the Semi-arid Region of India: A Study using GloPEM Model

    NASA Astrophysics Data System (ADS)

    Gholkar, M. D.; Goroshi, S.; Singh, R. P.; Parihar, J. S.

    2014-11-01

    The present study aims to assess the effect of agricultural developments on inter-annual variations in the agricultural Net Primary Productivity (NPP) of selected districts of the semi-arid region of India by using GloPEM model. Advancements in farming practices have been contributing to the increase of net primary productivity, which ultimately leads to increase in the agricultural production. The study shows that increase in the gross irrigated area, fertilizer consumption, use of high yielding crop varieties and adoption of agricultural mechanization in terms of tractors and irrigation pumps have contributed significantly in the increase in agricultural NPP in the semi-arid region of India. The agricultural NPP of the semi-arid region of India has shown a very good correlation with the gross irrigated area (R2 = 0.668) and fertilizer use (R2 = 0.701). The anthropogenic factors influencing the agricultural NPP were grouped in 3 major Factor Components (FC) (eigenvalues > 1) as: FC1-nutrients application, FC2-irrigation potential and agricultural mechanization (irrigation pumps and tractors) and irrigated area while FC3-cultivated area and area under high yielding crop varieties. The study showed that most of the semi-arid region of India has a good agricultural production potential which needs to harness by increasing the supply of irrigation water, promoting agricultural mechanization and adoption of integrated nutrient management approach.

  16. Long-term soil microbial community and enzyme activity responses to an integrated cropping-livestock system in a semi-arid region

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water availability is a significant factor limiting agriculture in many semiarid or arid regions of the world. This study is part of a larger project to develop and evaluate integrated crop and livestock systems that reduce dependence on underground water while optimizing cotton (Gossypium hirsutum)...

  17. Assessment of Grazing Effect on Sheep Fescue (Festuca valesiaca)Dominated Steppe Rangelands in the semi-arid Central Anatolian Region of Turkey

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because of increased grazing pressure over the last fifty years, vegetation of the steppe rangelands in the semi-arid Central Anatolian Region of Turkey has been severely degraded. In these pastures, Festuca valesiaca (a sod forming short-grass) and Thymus sipyleus ssp rosulans (a prostrate shrub) a...

  18. Occurrence and availability of ground water in the Athens region, northeastern Georgia

    USGS Publications Warehouse

    Radtke, D.B.; Cressler, C.W.; Perlman, H.A.; Blanchard, H.E.; McFadden, K.W.; Brooks, Rebekah

    1986-01-01

    A study was conducted to assess the occurrence and availability of groundwater in the crystalline rocks of the Piedmont area in northeastern Georgia and to determine whether groundwater is a viable alternative or supplemental source for industrial, public and private supplies. The area is underlain by a variety of metamorphic and igneous rocks. The quantity of water that a rock unit can supply to wells is determined by the number, capacity, and interconnection of the secondary openings. Of an estimated 10,000 successful wells drilled in the Athens Region, 972 wells are reported by drilling contractors to supply from 20 to 300 gal/min. Studies of well sites revealed that high yielding wells can be developed only where the water bearing units have undergone significant increases in secondary permeability. This occurs mainly in association with (1) contact zones between rock units of contrasting character, (2) contact zones within multilayered rock units, (3) fault zones, (4) stress-relief fractures, and (5) shear zones. Groundwater may be a viable alternative or supplemental source for industrial, public, and private supplies in much of the Athens Region. In 1980, groundwater made up 38% (18 million gal/day) of the total water used in the area. Yields of 20 to more than 200 gal/min are obtained from wells throughout most of the region, and the water is generally of good chemical quality and is suitable for drinking and many other uses. Concentrations of dissolved constituents are fairly consistent throughout the area. Except for iron, manganese, and fluoride, dissolved constituents rarely exceed drinking water standards. (Lantz-PTT)

  19. Regional movements of the tiger shark, Galeocerdo cuvier, off Northeastern Brazil: inferences regarding shark attack hazard.

    PubMed

    Hazin, Fábio H V; Afonso, André S; De Castilho, Pedro C; Ferreira, Luciana C; Rocha, Bruno C L M

    2013-09-01

    An abnormally high shark attack rate verified off Recife could be related to migratory behavior of tiger sharks. This situation started after the construction of the Suape port to the south of Recife. A previous study suggested that attacking sharks could be following northward currents and that they were being attracted shoreward by approaching vessels. In this scenario, such northward movement pattern could imply a higher probability of sharks accessing the littoral area of Recife after leaving Suape. Pop-up satellite archival tags were deployed on five tiger sharks caught off Recife to assess their movement patterns off northeastern Brazil. All tags transmitted from northward latitudes after 7-74 days of freedom. The shorter, soak distance between deployment and pop-up locations ranged between 33-209 km and implied minimum average speeds of 0.02-0.98 km.h-1. Both pop-up locations and depth data suggest that tiger shark movements were conducted mostly over the continental shelf. The smaller sharks moved to deeper waters within 24 hours after releasing, but they assumed a shallower (< 50 m) vertical distribution for most of the monitoring period. While presenting the first data on tiger shark movements in the South Atlantic, this study also adds new information for the reasoning of the high shark attack rate verified in this region.

  20. NEAR-INFRARED POLARIZATION SOURCE CATALOG OF THE NORTHEASTERN REGIONS OF THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Kim, Jaeyeong; Pak, Soojong; Jeong, Woong-Seob; Park, Won-Kee; Tamura, Motohide E-mail: jeongws@kasi.re.kr

    2016-01-15

    We present a near-infrared band-merged photometric and polarimetric catalog for the 39′ × 69′ fields in the northeastern part of the Large Magellanic Cloud (LMC), which were observed using SIRPOL, an imaging polarimeter of the InfraRed Survey Facility. This catalog lists 1858 sources brighter than 14 mag in the H band with a polarization signal-to-noise ratio greater than three in the J, H, or K{sub s} bands. Based on the relationship between the extinction and the polarization degree, we argue that the polarization mostly arises from dichroic extinctions caused by local interstellar dust in the LMC. This catalog allows us to map polarization structures to examine the global geometry of the local magnetic field, and to show a statistical analysis of the polarization of each field to understand its polarization properties. In the selected fields with coherent polarization position angles, we estimate magnetic field strengths in the range of 3−25 μG using the Chandrasekhar–Fermi method. This implies the presence of large-scale magnetic fields on a scale of around 100 parsecs. When comparing mid- and far-infrared dust emission maps, we confirmed that the polarization patterns are well aligned with molecular clouds around the star-forming regions.

  1. Spatio-temporal variation in a seed bank of a semi-arid region in northeastern Brazil

    NASA Astrophysics Data System (ADS)

    da Silva, Kleber A.; dos Santos, Danielle M.; dos Santos, Josiene M. F. F.; de Albuquerque, Ulysses P.; Ferraz, Elba M. N.; Araújo, Elcida de L.

    2013-01-01

    This study aimed to evaluate variations in the seed bank within a 3-year temporal series in order to answer the following questions: 1) Does the seed bank's species richness and seed density differ among climatic seasons and between years? 2) Are there differences in the richness and density of seed banks between the litter and mineral soil? 3) Can the seed bank's species richness and seed density be explained by characteristics such as the previous year's precipitation and soil depth (litter or mineral soil)? The samples were collected from litter and mineral soil (0-5 cm), in 210 sub-plots, during the dry and rainy seasons of each year (August 2005 through February 2008). Overall, 79 species were recorded. On average, 1 168, 304 and 302 seeds.m-2 were recorded in the seed bank during years I, II and III, respectively. This study showed that the Caatinga's seed bank is rich in herbaceous species, yet species' density and richness are low in the litter. Furthermore, about 43% of the variation in species richness and density was explained by soil depth (litter and mineral soil) and previous years' rainfall.

  2. An analysis of global climate-vegetation interactions over arid and semi-arid regions via causal statistics

    NASA Astrophysics Data System (ADS)

    Eibedingil, Iyasu; Casagrande, Erik; Molini, Annalisa

    2014-05-01

    Precipitation and Temperature are two of the major drivers of ecosystem dynamics. Their control is the result of complex dynamical interactions, often non-linear, and is exerted over a wide range of space and temporal scales. Rainfall intermittency, as an example, is known to be among the main drivers of plants production, with a consequent influence on carbon and nitrogen cycles. However, a clear understanding of the complete pathway of such a forcing remains still unclear. Traditional time series analysis bases the study of these inter-connections on linear correlation statistics. However, the possible presence of causal dynamical connections, as well as non-linear couplings and non-stationarity can affect the performance of these tools. Additionally, dynamical drivers can act simultaneously over different space and time scales. Given this premise, this talk explores different approaches to the estimation of global causal relationships between two main climatic variables (temperature and precipitation) and vegetation over arid and transitional (semi-arid) regions. By using monthly globally gridded precipitation and temperature data (University of Delaware, NOAA/ESRL/PSD) and remotely sensed normalized difference vegetation index (NDVI, Global Inventory Modeling and Mapping Studies-GIMMS) as a proxy of vegetation dynamics we explore possible direct and conditional causal relationships between climate and vegetation. Pairwise Granger causality (GC) test is applied in order to assess bi-directional causal influences between each couple of variables due to their direct interaction and instantaneous causality deriving from exogenous variables. In addition to this, conditional Granger causality tests were performed on the three variables system. Conditional GC has the ability to resolve whether the interaction between two variables is direct or is mediated by a third variable, and whether the causal influence is simply due to differential time delays in their

  3. Remote sensing-based vegetation indices for monitoring vegetation change in the semi-arid region of Sudan

    NASA Astrophysics Data System (ADS)

    R. A., Majdaldin; Osunmadewa, B. A.; Csaplovics, E.; Aralova, D.

    2016-10-01

    Land degradation, a phenomenon referring to (drought) in arid, semi-arid and dry sub-humid regions as a result of climatic variations and anthropogenic activities most especially in the semi-arid lands of Sudan, where vast majority of the rural population depend solely on agriculture and pasture for their daily livelihood, the ecological pattern had been greatly influenced thereby leading to loss of vegetation cover coupled with climatic variability and replacement of the natural tree composition with invasive mesquite species. The principal aim of this study is to quantitatively examine the vigour of vegetation in Sudan through different vegetation indices. The assessment was done based on indicators such as soil adjusted vegetation index (SAVI). Cloud free multi-spectral remotely sensed data from LANDSAT imagery for the dry season periods of 1984 and 2009 were used in this study. Results of this study shows conversion of vegetation to other land use type. In general, an increase in area covered by vegetation was observed from the NDVI results of 2009 which is a contrast of that of 1984. The results of the vegetation indices for NDVI in 1984 (vegetated area) showed that about 21% was covered by vegetation while 49% of the area were covered with vegetation in 2009. Similar increase in vegetated area were observed from the result of SAVI. The decrease in vegetation observed in 1984 is as a result of extensive drought period which affects vegetation productivity thereby accelerating expansion of bare surfaces and sand accumulation. Although, increase in vegetated area were observed from the result of this study, this increase has a negative impact as the natural vegetation are degraded due to human induced activities which gradually led to the replacement of the natural vegetation with invasive tree species. The results of the study shows that NDVI perform better than by SAVI.

  4. Water Use and Management in Semiarid Regions - A Distributed Modelling Approach in the Verlorenvlei Catchment, South Africa

    NASA Astrophysics Data System (ADS)

    Fleischer, Melanie; Kralisch, Sven; Fink, Manfred; Pfennig, Björn; Butchart-Kuhlmann, Daniel; Meinhardt, Markus; de Clercq, Willem

    2016-04-01

    Hydrological modelling is a useful method to predict water availability and environmental impacts in a range of climate and land use change scenarios. One of the major challenges to accurate predictions using hydrological modelling in semi-arid areas is the high temporal and spatial variability of rainfall events and the associated uncertainty of related process parameters. Limited and often unreliable climate observations can cause additional problems. These particular circumstances are well documented for many catchments in the world, including semi-arid parts of South Africa. An accurate assessment of water quality and quantity is however crucial for sustainable water resource management, which is often difficult under changing environmental conditions such as climate and land use change. This situation can be found in the Verlorenvlei catchment, a part of the Sandveld area located in the Western Cape region of South Africa. Extensive dry periods in combination with an increasing domestic water demand, expanding irrigation agriculture and expected reducing rainfall due to climate change present a challenging setup for water management in this region. The catchment is a highly sensitive area with one of the most important estuary systems in the Western Cape region, containing significant natural wetlands with high biodiversity and numerous endemic species. With very limited surface water resources, most settlements and irrigation systems in the region are mainly dependent on groundwater. As a result of the particular conditions, the use of improved management techniques, such as centre pivot irrigation and contour-bank farming, are necessary. The distributed, process-oriented hydrological modelling system JAMS/J2000 is used and evaluated to assess water availability within the catchment under different climate and land-use change scenarios. The first phase has involved configuring the model to accurately represent the specific natural conditions of the

  5. Monoterpene emissions from Pinus halepensis forests in a semi-arid region (Israel)

    NASA Astrophysics Data System (ADS)

    Seco, R.; Karl, T.; Turnipseed, A. A.; Greenberg, J.; Guenther, A. B.; Llusia, J.; Penuelas, J.; Kim, S.; Dicken, U.; Rotenberg, E.; Rohatyn, S.; Preisler, Y.; Yakir, D.

    2013-12-01

    Atmospheric volatile organic compounds (VOCs) have key environmental and biological roles, and can affect atmospheric chemisty, secondary aerosol formation, and as a consequence also climate. At the same time, global changes in climate arising from human activities can modify the VOC emissions of vegetation in the coming years. Monoterpene emission fluxes were measured during April 2013 at two forests in the semi-arid climate of Israel. Both forests were dominated by the same pine species, Pinus halepensis, but differed in the amount of annual average precipitation received (280 and 800 mm at Yatir and Birya, respectively). Measurements performed included leaf-level sampling as well as canopy-level flux calculations. Leaf level monoterpene emissions were sampled from leaf cuvettes with adsorbent cartridges and later analyzed by GC-MS. Canopy scale fluxes were calculated with the Disjunct Eddy Covariance technique by means of a Quadrupole PTRMS. We report the differences observed between the two forests in terms of photosynthetic activity and monoterpene emissions, aiming to see the effect of the different precipitation regimes at each location.

  6. Use of alternative plant resources by common marmosets (Callithrix jacchus) in the semi-arid caatinga scrub forests of northeastern Brazil.

    PubMed

    Amora, Tacyana Duarte; Beltrão-Mendes, Raone; Ferrari, Stephen F

    2013-04-01

    The common marmoset (Callithrix jacchus) is amply distributed in the Brazilian Northeast, but little is known of its ecology in the semi-arid Caatinga scrublands. The present study provides the first detailed data on the composition of the diet of C. jacchus in Caatinga ecosystems, derived from observations at four sites in the state of Sergipe. While exudate sources were gouged at all four sites in a manner typical of the species, fruit was the principal component of the diet at the main study site during most months, and a number of unusual items were eaten, including leaves, and the reproductive parts of cacti and bromeliads. These plants are rarely recorded in marmoset diets, but are common in caatinga habitats. Leaves were ingested during 5 of the 8 months monitored at the main study site, reaching 39.74% of the diet in 1 month, and appeared to be an alternative fallback food to plant exudates during periods when fruit was scarce. Three species of cactus provided both flowers and fruits, while the terrestrial bromeliad, Encholirium spectabile, provided nectar (30.81% of the diet in November). Approximately half of the plant species (and three families) identified in this study had not been recorded previously in the diet of Callithrix. Overall, the data suggest that, while the marmosets exploit the same types of plant foods in the Caatinga, the resource base is quite distinct from that of the Atlantic Forest. Other differences, such as relatively small groups and large home ranges, may contribute to divergent ecological patterns, which require more systematic investigation. Am. J. Primatol. 75:333-341, 2013. © 2012 Wiley Periodicals, Inc.

  7. Development and Validation of a MODIS-based Actual Evapotranspiration for Ecosystems in Semi-arid Regions

    NASA Astrophysics Data System (ADS)

    Hogue, T. S.; Kim, J.

    2009-12-01

    Although remote sensing shows promise for estimating global or regional evapotranspiration (ET), direct measurement from satellite systems is still challenging due to the numerous variables required for many of the existing ET algorithms and models. However, remote sensing does provide reasonable estimates of the evaporative fraction (EF), which is defined as the ratio of ET to available energy. In the current study, spatially distributed estimates of actual evapotranspiration are pursued through estimation of EF using a simple remote sensing technique based on an Enhanced Vegetation Index (EVI) and diurnal changes in land surface temperature (LST) obtained from the MODIS AQUA platform. Combining the diurnal change in surface temperature with an interpretation of the triangular-shaped space (temperature-EVI) allows for a direct approximation of the evaporative fraction. A mean daytime potential evapotranspiration (PET) is estimated using a previously developed procedure based on the Priestley-Taylor’s equation and MODIS data products. Finally, regional estimates of actual evapotranspiration are made by combining the derived evaporative fraction and the MODIS-based PET estimates. Both estimated PET and actual ET are validated against flux tower observations in southern Arizona for 2004. Initial results show good approximation of ET in riparian zones using the satellite-based algorithms, but more uncertainty is observed in rangeland (upland) areas. Ongoing work includes improvement in the EF/ET estimation and investigating the factors controlling ET in the diverse landscapes in semi-arid regions.

  8. Three-dimensional Mechanical Modeling of the GPS Velocity Field around the Northeastern Tibet and Surrounding Region

    NASA Astrophysics Data System (ADS)

    He, J.; Li, Y.; Teng, C.

    2004-12-01

    The northeastern Tibet and surrounding region is an intense active tectonic area with great potential of strong earthquakes. Active tectonics is featured mainly by left-lateral transpressive deformation along the Qilian Shan and right-lateral transtensional deformation between the Alashan and the Ordos blocks out of the Tibet. This region gives a good example to investigate how the strain rate is partitioning around the plateau edge and how the remainder strain rate of Tibetan deformation is propagating towards the interior of the Eurasia plate with relative to the Indian-Eurasia convergence. In this study, we use three-dimensional mechanical models incorporated the main active faults as Coulomb-type friction zones to simulate the surface velocity field as dense GPS data shown. We simplify the rheological structure of lithosphere as a frictional upper crust underlying with the viscoelastic lower crust with available heat flow. Topographic loading on the model surface and hydrostatic pressure on the model base are added. The models are solved with Adeli finite element code, and modeled velocities are checked using the chi-square merit function with dense GPS data. We test the model with fault friction ranged from 0.4 to 0.01 on different major fault systems. Results show: (1) with a relatively high fault friction ~0.4-0.2, the northeastern Tibet and surrounding region could behave like diffusive deformation, but the modeled velocities and the strain rate seem unable to fit the GPS data and the seismic data, respectively. (2) To best fit the GPS data, a relatively low fault friction ~0.05-0.02 is needed. At this condition, the deformation is localized mainly around the Qilian Shan in northeastern Tibet and between the Alashan and the Ordos blocks out of the Tibet, consistent with the active tectonics and the strong earthquake distribution. (3) Changes of the fault friction out of the Tibet seem to affect the modeled velocity quite small, suggesting that the

  9. A review of groundwater recharge estimation in humid and semi-arid African regions

    NASA Astrophysics Data System (ADS)

    Chung, Il-Moon; Kim, Nam Won

    2016-04-01

    For the review of African recharge estimation, the distinct methods such as the geochemical approach, a method using groundwater level data, the streamflow method, and the water balance methods were first outlined. The major challenge of an African recharge study is the lack of basic data. Thus, this work suggests how to deal with this limitation and from future perspective using recently developed technologies such as RS, GIS, etc. With the rapid growth of information technology, more and more data, in terms of both volume and variety, are expected to be made available on the internet in the near future. RS technology has a great potential to revolutionize the groundwater development and management in the future by providing unique and completely new hydrological and hydrogeological data. However, at present, the RS data should be considered along with the conventional field data. In spite of the weaknesses of water balance methods in semi-arid areas, recently developed water balance methods combined with GIS technology are powerful tools for estimating groundwater re-charge, when spatial-temporal variability of components in water balance is taken into account (Lerner et al., 1990; De Vries and Simmers, 2002; Eilers et al., 2007).When enough data sets are available, integrated surface-groundwater modeling is recommended for more accurate estimation of groundwater recharge and discharge. Acknowledgements This work was supported by a grant(14RDRP-B076275-01-000000) from Infrastructure and transportation technology promotion research Program funded by the Ministry of Land, Infrastructure and Transport of Korean government.

  10. The Influence of Land Use on the Grassland Fire Occurrence in the Northeastern Inner Mongolia Autonomous Region, China

    PubMed Central

    Li, Yiping; Zhao, Jianjun; Guo, Xiaoyi; Zhang, Zhengxiang; Tan, Gang; Yang, Jihong

    2017-01-01

    Grassland, as one of the most important ecosystems on Earth, experiences fires that affect the local ecology, economy and society. Notably, grassland fires occur frequently each year in northeastern China. Fire occurrence is a complex problem with multiple causes, such as natural factors, human activities and land use. This paper investigates the disruptive effects of grassland fire in the northeastern Inner Mongolia Autonomous Region of China. In this study, we relied on thermal anomaly detection from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to identify fire occurrences, and land use data were acquired by Landsat Thematic Mapper/Enhanced Thematic Mapper (TM/ETM). We discussed the relationship between land use and the spatial distribution of grassland fires. The results showed that the impact of land use on grassland fires was significant. Spatially, approximately 80% of grassland fires were clustered within 10 km of cultivated land, and grassland fires generally occurred in areas of intense human activity. The correlation between the spatial distribution of grassland fires and the land use degree in 2000, 2005 and 2010 was high, with R2 values of 0.686, 0.716, 0.633, respectively (p < 0.01). These results highlight the importance of the relationship between land use and grassland fire occurrence in the northeastern Inner Mongolia Autonomous Region. This study provides significance for local fire management and prevention. PMID:28241476

  11. The Influence of Land Use on the Grassland Fire Occurrence in the Northeastern Inner Mongolia Autonomous Region, China.

    PubMed

    Li, Yiping; Zhao, Jianjun; Guo, Xiaoyi; Zhang, Zhengxiang; Tan, Gang; Yang, Jihong

    2017-02-23

    Grassland, as one of the most important ecosystems on Earth, experiences fires that affect the local ecology, economy and society. Notably, grassland fires occur frequently each year in northeastern China. Fire occurrence is a complex problem with multiple causes, such as natural factors, human activities and land use. This paper investigates the disruptive effects of grassland fire in the northeastern Inner Mongolia Autonomous Region of China. In this study, we relied on thermal anomaly detection from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor to identify fire occurrences, and land use data were acquired by Landsat Thematic Mapper/Enhanced Thematic Mapper (TM/ETM). We discussed the relationship between land use and the spatial distribution of grassland fires. The results showed that the impact of land use on grassland fires was significant. Spatially, approximately 80% of grassland fires were clustered within 10 km of cultivated land, and grassland fires generally occurred in areas of intense human activity. The correlation between the spatial distribution of grassland fires and the land use degree in 2000, 2005 and 2010 was high, with R² values of 0.686, 0.716, 0.633, respectively (p < 0.01). These results highlight the importance of the relationship between land use and grassland fire occurrence in the northeastern Inner Mongolia Autonomous Region. This study provides significance for local fire management and prevention.

  12. Region and site specific design guidelines for the northeastern Venezuela development

    SciTech Connect

    Gajardo, E.; Paga, M.; Sully, J.P.

    1996-12-31

    Several site specific studies were performed for the northeastern Venezuelan offshore development in order to determine the environmental parameters for the engineering design. The geotechnical parameters were obtained from the analysis of the soil borings, in situ tests and the high resolution seismic surveys. An evaluation of the seismic hazard was done, based on a detailed neotectonic study, the compilation of historical and instrumental seismological information, and an attenuation relationship developed for the studied area. Seismic response analyses were performed using the seismic parameters and dynamic characteristics obtained form the soil borings and in situ tests of shear waves. The met-ocean design loads of the local conditions were obtained from mathematical modeling based on in situ and regional measurements. This study defines the platforms design conditions based on a probabilistic reliability approach and it has been used, among others, as a basis for the earthquake design guidelines proposed by the International Standards Organization. A sensitivity analysis was performed starting from the uncertainties of all the input parameters, in order to obtain the best estimate average design spectrum and associated coefficient of variability. The specific approach was to maintain the same safety index adopted by API RP2A code, with a bias modification factor that relates the site nominal spectra with the spectral acceleration that would be used in order to satisfy the API requirements. The results of this approach make possible the use of site specific detailed environmental data and the proven standard procedures established on the API RP2 codes, with significant cost reduction in terms of both platform and foundation design. The considerable amount of tectonic, seismological, and geotechnical information was the principal factor allowing the above methodology.

  13. Using online databases for landslide susceptibility assessment: an example from the Veneto Region (northeastern Italy)

    NASA Astrophysics Data System (ADS)

    Floris, M.; Iafelice, M.; Squarzoni, C.; Zorzi, L.; de Agostini, A.; Genevois, R.

    2011-07-01

    In this paper, spatial data available in the Italian portals was used to evaluate the landslide susceptibility of the Euganean Hills Regional Park, located SW of Padua (northeastern Italy). Quality, applicability and possible analysis scales of the online data were investigated. After a brief overview on the WebGIS portals around the world, their contents and tools for natural risk analyses, a susceptibility analysis of the study area was carried out using a simple probabilistic approach that compared landslide distribution and influencing factors. The input factors used in the analysis depended on available data and included landslides, morphometric data (elevation, slope, curvature, profile and plan Curvature) and non-morphometric data (land use, distance to roads and distance to rivers). Great attention was paid to the pre-processing step, in particular the re-classification of continuous data that was performed following objective, geologic and geomorphologic criteria. The results of the study show that the simple probabilistic approach used for the susceptibility evaluation showed quite good accuracy and precision (repeatability). However, heuristic, statistical or deterministic methods could be applied to the online data to improve the prediction. The data available online for the Italian territory allows susceptibility assessment at medium and large scales. Morphometric factors, such as elevation and slope angle, are important because they implicitly include information that is not available, such as lithologic and structural data. The main drawback of the Italian online databases is the lack of information on the frequency of landslides; thus, a complete hazard analysis is not possible. Despite the good results achieved to date, collection and sharing of data on natural risks must be improved in Italy and around the world. The creation of spatial data infrastructure and more WebGIS portals is desirable.

  14. Prediction of soil stability and erosion in semiarid regions using numerical hydrological model (MCAT) and airborne hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Brook, Anna; Wittenberg, Lea

    2015-04-01

    Long-term environmental monitoring is addressed to identify physical and biological changes and progresses taking place in the ecosystem. This basic action of landscape monitoring is an essential part of the systematic long-term surveillance, aiming to evaluate, assess and predict the spatial change and progresses. Indeed, it provides a context for wide range of diverse studies and research frameworks from regional or global scale. Spatial-temporal trends and changes at various scales (massive to less certain) require establishing consistent baseline data over time. One of the spatial cases of landscape monitoring is dedicated to soil formation and pedological progresses. It is previously acknowledged that changes in soil affect the functionality of the environment, so monitoring changes recently become important cause considerable resources in areas such as environmental management, sustainability services, and protecting the environment healthy. Given the above, it can be concluded that monitoring changes in the base for sustainable development. The hydrological response of bare soils and watersheds in semiarid regions to intense rainfall events is known to be complex due to multiply physical and structural impacts and feedbacks. As a result, the comprehensive evaluations of mathematical models including detailed consideration of uncertainties in the modeling of hydrological and environmental systems are of increasing importance. The presented method incorporates means of remote sensing data, hydrological and climate data and implementing dedicated and integrative Monte Carlo Analysis Toolbox (MCAT) model for semiarid region. Complexity of practical models to represent spatial systems requires an extensive understanding of the spatial phenomena, while providing realistic balance of sensitivity and corresponding uncertainty levels. Nowadays a large number of dedicated mathematical models applied to assess environmental hydrological process. Among the most

  15. Structure and dynamics of the phytoplankton community within a maturation pond in a semiarid region.

    PubMed

    Pastich, E A; Gavazza, S; Casé, M C C; Florencio, L; Kato, M T

    2016-02-01

    In northeastern Brazil, stabilization ponds are very suitable for wastewater treatment because of the relative great land availability and environmental conditions (e.g., high temperature) favorable for microorganism optimal development. However, blooms of potentially toxic cyanobacteria may affect the use of these treatment ponds due to resulting effluent poor quality. The objective of this study was to evaluate the dynamics of phytoplankton communities and the occurrence of cyanobacteria in a maturation pond located immediately after a series of two ponds. Temperature, dissolved oxygen, pH, BOD, N, and P were measured during a period of four months when samples were collected from the surface and the bottom of 7 sampling points distributed inside the pond. The phytoplankton of collected samples was also identified and classified using a conventional optical microscopy. Analysis of variance and Tukey test were used to evaluate the results. The three phytoplankton divisions found (Cyanophyta, Chlorophyta, and Euglenophyta) did not change considerably through surface and bottom. However, they changed greatly over the sampled months; great dominance of Cyanophyta was found at April and October, while Chlorophyta dominated the lagoon in September. Low superficial organic loads (between 78 and 109 kg BOD.ha-1.d-1) and N:P ≤ 10 were the determinant factors that favored the predominance of Cyanophyta. The presence of two potentially toxic species of Cyanophyta, Oscillatoria sp. and Microcystis aeruginosa, indicates that caution is required when considering the final destination of treated effluent and suggests a need to assess the risks and benefits associated with the use of the treatment technology.

  16. Exploring the Consequences of Changing Land Surface Phenology on Regional Hydrometeorology in the Eurasian Semi-Arid Grain Belt

    NASA Astrophysics Data System (ADS)

    Capehart, W. J.; Henebry, G. M.; de Beurs, K. M.

    2007-12-01

    Have the changes in land surface phenology following the 1991 collapse of the Soviet Union affected the regional hydrometeorology of the semi-arid grain belt that extends from northern Kazakhstan westward across southern Russia into eastern Ukraine? We modified MM5 running as a regional climate model with the NOAH land surface scheme to accept an updated fractional vegetation cover (FVC) layer every ten days. This new FVC time series was generated from the PAL NDVI dataset using the recent Scaled Vegetation Index algorithm (Jiang et al. 2006 RSE 101:366-378). The seasonal study period ran from March through September. We focused on years before and after the disintegration of the Soviet Union that were selected considering that the North Atlantic Oscillation (NAO) has been shown to affect conditions in at least part of the study area. We present results for 1985 (neutral NAO), 1989 (high NAO), 1996 (low NAO), and 1997 (neutral NAO). We focus on two response fields: monthly total precipitation and monthly specific humidity at 850 hPa. There are substantial spatially coherent differences between predictions from the default MM5 FVC series and the new FVC series as measured by RMSE and bias. Use of the new FVC image time series enables MM5/NOAH to respond to a more realistic representation of the tempo and spatial heterogeneity of land surface phenology.

  17. Reducing Occurrence of Giardia duodenalis in Children Living in Semiarid Regions: Impact of a Large Scale Rainwater Harvesting Initiative

    PubMed Central

    Fonseca, Jacqueline Evangelista; Carneiro, Mariângela; Pena, João Luiz; Colosimo, Enrico A.; da Silva, Nívea Bispo; Costa, André Gabriel F. C. da.; Moreira, Luciano E.; Cairncross, Sandy; Heller, Léo

    2014-01-01

    Background In Brazil, about two million people living in rural semiarid regions were benefited with the construction of rainwater cement cisterns, as an initiative from the program “One Million Cisterns” (P1MC). Nevertheless, few epidemiological studies have been conducted to assess health risks or protection effects associated with consumption of this water source. The aim of this study was to evaluate whether access to rainwater harvesting cisterns is associated with the decrease in the occurrence of Giardia duodenalis infections in children, compared to other children living in households supplied by other water sources. Methodology/Principal Findings A quasi-experimental study with two concurrent cohorts was developed in two rural municipalities of the semiarid region of Brazil. A sample of 664 children, aged between 4 months and 5 years old, was followed up, of which 332 had access to rainwater cisterns (cistern group) and 332 did not, having water supplied from alternative sources (comparison group). In a period of approximately one year (2010) intestinal parasites were investigated in feces three times. The prevalence of G. duodenalis in children from the cistern group ranged from 4.8 to 10.5%, while the prevalence in the comparison group ranged from 7.6 to 16.7%. Multivariate analysis (GEE) showed a higher risk of G. duodenalis infection in children who did not have access to rainwater cisterns, when compared to children who did (OR 1.72; 95% CI 1.14–2.59). The other variables associated with G. duodenalis infection were: number of rooms per house (OR 0.89; 95% CI 0.80–0.99); family income (OR0.48; 95% CI 0.26–0.88); birth order (OR 1.72; 95% CI 1.17–2.51); preterm children (OR 1.70; 95% CI 1.19–2.43); and improper hand hygiene prior to food preparation (OR 4.78; 95% CI 1.95–11.76). Conclusions/Significance Ownership of a rainwater cistern is associated with a lower prevalence of G. duodenalis infection in children after adjustment for

  18. Sensitivity analysis of C- and Ku-band synthetic aperture radar data to soil moisture content in a semiarid region

    NASA Astrophysics Data System (ADS)

    Sano, Edson Eyji

    In this study, the sensitivity of the C-band (5.3 GHz) with a 23sp° incidence angle and the Ku-band (14.85 GHz) with 35sp° ,\\ 55sp° , and 75sp° incidence angles to surface soil moisture content from a semiarid region were evaluated. To obtain an improved soil moisture estimation, a practical technique to reduce the influence of soil roughness and vegetation in the SAR data was developed in a study area located in the Walnut Gulch Experimental Watershed, a representative site of shrub- and grass-dominated rangelands of the southwestern part of the United States. To correct for soil roughness effects, the C-band radar backscattering coefficients sigmasp° from a wet season image were subtracted from sigmasp° derived from a dry season image. The assumption was that, in semiarid regions, the SAR data from the dry season was dependent only on the soil roughness effects. To correct for vegetation effects, an empirical relation between sigmasp° and leaf area index was used, the latter derived from Landsat Thematic Mapper data. The results showed that when both soil roughness and vegetation effects were corrected for, the sensitivity of sigmasp° to soil moisture improved substantially. The sensitivity of sigmasp° to soil moisture was also evaluated in agricultural fields with bare soil and periodic roughness components (planting row and furrow structures). Four types of SAR system configurations were analyzed: C-band with a 23sp° incidence angle and Ku-band with 35sp° ,\\ 55sp° , and 75sp° incidence angles. The test sites were located at the University of Arizona's Maricopa Agricultural Center, south of Phoenix, Arizona. The results showed that the sensitivity of sigmasp° to soil moisture was strongly dependent upon the field conditions. The SAR signal was nearly insensitive to soil moisture for furrowed fields (furrow spacing ˜95 cm; amplitude ˜22 cm), but for fields with planting row structures (row spacing ˜24 cm; amplitude ˜2 cm), the SAR data was

  19. Quantification of methane emissions from natural gas extraction from the Haynesville, Fayetteville, and northeastern Marcellus shale regions

    NASA Astrophysics Data System (ADS)

    Peischl, J.; Ryerson, T. B.; Trainer, M.; De Gouw, J. A.; Warneke, C.; Parrish, D. D.

    2013-12-01

    We present airborne measurements of methane over three regions of natural gas extraction taken aboard a NOAA WP-3D research aircraft in June and July, 2013, as part of the Southeast Nexus (SENEX) field project. The three regions are (1) the Haynesville and (2) Fayetteville shale plays, located in eastern Texas/western Louisiana and western Arkansas, respectively, and (3) a part of the Marcellus shale play located in northeastern Pennsylvania. From these measurements, we derive methane emission rate estimates by calculating the methane advection flux in the planetary boundary layer downwind of the region, minus the methane flux upwind of the region. By attributing the methane emissions to natural gas extraction, we place an upper limit on the natural gas emissions from the region. We then compare this emission to the total volume of natural gas extracted from the region to derive an upper limit on the natural gas leak rate from extraction operations.

  20. Aerosol radiative effects over global arid and semi-arid regions based on MODIS Deep Blue satellite observations

    NASA Astrophysics Data System (ADS)

    Hatzianastassiou, Nikolaos; Papadimas, Christos D.; Gkikas, Antonis; Matsoukas, Christos; Sayer, Andrew M.; Hsu, N. Christina; Vardavas, Ilias

    2014-05-01

    Aerosols are a key parameter for several atmospheric processes related to weather and climate of our planet. Specifically, the aerosol impact on Earth's climate is exerted and quantified through their radiative effects, which are induced by their direct, indirect and semi-direct interactions with radiation, in particular at short wavelengths (solar). It is acknowledged that the uncertainty of present and future climate assessments is mainly associated with aerosols and that a better understanding of their physico-chemical, optical and radiative effects is needed. The contribution of satellites to this aim is important as a complementary tool to climate and radiative transfer models, as well as to surface measurements, since space observations of aerosol properties offer an extended spatial coverage. However, such satellite based aerosol properties and associated model radiation computations have suffered from unavailability over highly reflecting surfaces, namely polar and desert areas. This is also the case for MODIS which, onboard the Terra and Aqua satellites, has been providing high quality aerosol data since 2000 and 2002, respectively. These data, more specifically the aerosol optical depth (AOD) which is the most important optical property used in radiative and climate models, are considered to be of best quality. In order to address this problem, the MODIS Deep Blue (DB) algorithm has been developed which enables the retrieval of AOD above arid and semi-arid areas of the globe, including the major deserts. In the present study we make use of the FORTH detailed spectral radiative transfer model (RTM) with MODIS DB AOD data, supplemented with single scattering albedo (SSA) and asymmetry parameter (AP) aerosol data from the Global Aerosol DataSet (GADS) to estimate the aerosol DREs over the arid and semi-arid regions of the globe. The RTM is run using surface and atmospheric data from the ISCCP-D2 dataset and the NCEP global reanalysis project and computes the

  1. Three-dimensional mechanical modeling of the GPS velocity field around the northeastern Tibetan plateau and surrounding regions

    NASA Astrophysics Data System (ADS)

    He, Jiankun; Lu, Shuangjiang; Wang, Weimin

    2013-01-01

    The northeastern corner of the Tibetan plateau is a complex tectonic region with different fault mechanisms from left-lateral thrusting of the Qilian Shan, left-lateral strike slipping of the Haiyuan fault along the plateau edge, and right-lateral extension across the Alashan and the Ordos out of the northeastern Tibetan plateau. Here, we use 3D finite element models incorporating fault as Coulomb-type friction zone to investigate mechanical relation between crustal rheology and long-term deformation of the main active fault systems. Models are constrained with GPS velocity field and available geological slip rates. Crustal rheology is simplified as an elastobrittle upper part, underlying with viscoelastic crust. We test models with fault frictions (μ) from 0.4 to 0.02 on different fault systems, and mean viscosities (η) of the lower crust from 1019 Pa.s to 1021 Pa.s in the Tibetan plateau and 1021 Pa.s to 1023 Pa.s out of the Tibetan plateau. A common feature from the numerical experiments is that the Haiyuan fault reflects a low fault friction (μ < 0.1-0.08). The predicted low fault friction associated with the mean viscosities of the lower crust of ~ 1019 Pa.s in the Tibetan plateau and ~ 1021 Pa.s out of the Tibetan plateau can fit the geological slip rates well for the active faults. This suggests that slip partitioning around northeastern boundary of the Tibetan plateau is related mechanically to the low fault friction. Numerical experiments also show that after strain rates are absorbed by the main fault systems, the rest are strongly affected by crustal rheology. Finally, even the fault friction decreases to ~ 0.05, the mean viscosities of lower crust attain to 1021 Pa.s and 1023 Pa.s in and out of the Tibetan plateau, the northeastern Tibetan plateau and the Alashan still deforms diffusively, except that the Ordos behaves more like a rigid block.

  2. The influence of agricultural management on soil's CO2 regime in semi-arid and arid regions

    NASA Astrophysics Data System (ADS)

    Eshel, G.; Lifshithz, D.; Sternberg, M.; Ben-Dor, E.; Bonfile, D. J.; Arad, B.; Mingelgrin, U.; Fine, P.; Levy, G. J.

    2008-12-01

    Two of the more important parameters which may help us better evaluate the impact of agricultural practices on the global carbon cycle are the in-situ soil pCO2 profile and the corresponding CO2 fluxes to the atmosphere. In an ongoing study, we monitored the pCO2 to a depth of 5 m in two adjacent irrigated Avocado orchards in the coastal plain of Israel (semi-arid region), and to a depth of 2 m in a semi- arid rain-fed and a arid rain-fed wheat fields in southern Israel. The soil pCO2 profiles and CO2 fluxes measurements were supplemented by measurements of soil moisture and temperature. The results showed differences in the CO2 profiles (both in the depth of the highest concentration and its absolute values) and the CO2 fluxes between the orchards and the wheat fields as well as along the year. In the irrigated Avocado orchards pCO2 values were in the range of 1.5 kPa at a depth of 0.5 m up to 8 kPa at depths of 3-5 m (even though Avocado trees are characterized by shallow roots). Such levels could affect reactions (e.g., enhancement of inorganic carbon dissolution) that may take place in the soil and some of its chemical properties (e.g., pH). As expected, soil pCO2 was affected by soil moisture and temperature, and the distance from the trees. Maximum soil respiration was observed during the summer when the orchards are under irrigation. In the wheat fields pCO2 level ranged from 0.2- 0.6 kPa at a depth of 0.2 m to 0.2-1 kPa at depths of 1-1.5 m (in arid and semiarid respectively). These pCO2 levels were much lower than those obtained in the irrigated orchards and seemed to depend on the wheat growing cycle (high concentration were noted at depth of 1-1.5 m close to the end of grain filling) and precipitation gradient (arid vs. semiarid). Since CO2 fluxes are directly affected by the pCO2 profile and soil moister and temperature the CO2 fluxes from the wheat fields were much lower (0.02- 0.2 ml min-1 m-2) compared to those obtained from the Avocado orchards (2

  3. Restoration of sodic soils involving chemical and biological amendments and phytoremediation by Eucalyptus camaldulensis in a semiarid region.

    PubMed

    Seenivasan, R; Prasath, V; Mohanraj, R

    2015-06-01

    Salt-affected soils in semiarid regions impede the agricultural productivity and degrade the ecosystem health. In South India, several hectares of land are salt-affected, where the evapotranspiration exceeds the annual precipitation. This study is an attempt to ameliorate sodic soils, by an experiment involving chemical treatment (addition of gypsum), organic amendments (decomposed bagasse pith and green manuring with Sesbania rostrata) and phytoremediation by plantation of Eucalyptus camaldulensis. The prime focus is to minimize the use of gypsum and improve the soil health in terms of nutrients, microbial population and enzyme activity in addition to sodicity reclamation. At the end of the third year, a reduction of 10 % in soil pH, 33 % in electrical conductivity and 20 % in exchangeable sodium percentage was achieved compared to the initial values. Three- to fourfold increases in organic carbon content were observed. Significant improvement in the available major and micronutrients of soil, microbial growth and enzyme activity was observed, suggesting phytoremediation by E. camaldulensis as a sustainable option for restoration of similar kind of degraded lands.

  4. Structural variations among monocot emergent and amphibious species from lakes of the semi-arid region of Bahia, Brazil.

    PubMed

    Leite, K R B; França, F; Scatena, V I

    2012-02-01

    Temporary lakes are common in the semi-arid region of the State of Bahia and form water mirrors in the rainy season. In this period, various vegetal species appear having different life forms adapted to the seasonality conditions of the rainfall regime. This work surveyed the adaptive anatomical structures of some emergent and amphibious monocot species occurring in these lakes. We studied the anatomy of roots, rhizomes, leaves and scapes of Cyperus odoratus, Oxycaryum cubense, Pycreus macrostachyos (Cyperaceae) - amphibious species; and of Echinodorus grandiflorus (Alismataceae), Eichhornia paniculata (Pontederiaceae) and Habenaria repens (Orchidaceae) - emergent species. The anatomical features of the dermal, fundamental and vascular systems confirming the tendency of the adaptive convergence of these plants to temporary lacustrine the environment include: single layered epidermal cells with a thin cuticle layer in the aerial organs; the presence of air canals in all the organs; few or no supporting tissues; and less numerous conducting elements and thinner cell walls in the xylem. The reduction of the supporting tissues, the number of stomata, which can even be absent, and the number of conducting elements and the degree of cell wall lignification in the xylem of the emergent species is more accentuated than that of the amphibious species. The pattern of distribution of aerenchyma in the roots of the studied species was considered important to distinguish between amphibious and emergent life forms.

  5. Evaluation of NEXRDA Stage III precipitation data over Sevilleta National Wildlife Refuge: a semiarid region in Central New Mexico

    NASA Astrophysics Data System (ADS)

    Xie, H.; Zhou, X.; Hendrickx, J.; Guan, H.

    2006-05-01

    This study examines NEXRAD Stage III product (hourly, cell size 4 km by 4 km) for its ability in estimating precipitation over Sevilleta National Wildlife Refuge: a semiarid region in Central New Mexico. A GIS-based NEXRAD data processing and visualization method is also presented. A comparison between Stage III and a network of gauge precipitation estimates during 1995 to 2001 indicates that Stage III (1) overestimates the hourly conditional mean precipitation (CM) by 33 percent in monsoon season and 55 percent in non-monsoon season; (2) overestimates the hourly CM for concurrent radar-gauge pairs (non-zero value) by 13 percent in monsoon season and 6 percent in non-monsoon season; (3) overestimates the seasonal precipitation accumulation by 11 to 88 percent in monsoon season and underestimates by 18 to 89 percent in non- monsoon season; and (4) either overestimates annual precipitation accumulation up to 28.2 percent or underestimates it up to 11.9 percent. More caution is suggested in using Stage III data for nonmonsoonal (stratiform) rainfall events (prior to the truncation fixed algorithm deployed in 2002), as the truncation error can be a significant drawback. While overestimates may suppress the truncation caused underestimates in the monsoon seasons.

  6. [Clinical-epidemiological aspects of pityriasis versicolor (PV) in a fishing community of the semiarid region in Falcon State, Venezuela].

    PubMed

    Acosta Quintero, María Eugenia; Cazorla Perfetti, Dalmiro José

    2004-12-01

    Between August 2001 and May 2002, the prevalence and several epidemiological and clinical characteristics of pityriasis versicolor (PV) were studied in 902 individuals aged two months- 60 years, 426 females and 476 males, from a fishery community of Río Seco, a semiarid region in the state of Falcon, north-western Venezuela. The overall prevalence of the disease was 15.52% (140/902). The frequency of infection was higher in females (65.7% vs. 34.3%), children under one year of age and adolescents (27.9% y 32.1%, respectively), and dark skin (67.9%). The most commonly affected anatomical areas were the face (57.9%) and thorax (27.1%). The most important clinical features of the disease were: hypochromic (91.4%), multicentric (73.6%), pruritic (92.9%), fine scaled (80.7%) and irregularly shaped borders (91.4%). On the basis of these results, the possible risk factors on transmission dynamic and maintenance of the disease endemically is discussed.

  7. Appraisal of salinity and fluoride in a semi-arid region of India using statistical and multivariate techniques.

    PubMed

    Mor, Suman; Singh, Surender; Yadav, Poonam; Rani, Versha; Rani, Pushpa; Sheoran, Monika; Singh, Gurmeet; Ravindra, Khaiwal

    2009-12-01

    Various physico-chemical parameters, including fluoride (F(-)), were analyzed to understand the hydro-geochemistry of an aquifer in a semi-arid region of India. Furthermore, the quality of the shallow and deep aquifer (using tube well and hand pumps) was also investigated for their best ecological use including drinking, domestic, agricultural and other activities. Different multivariate techniques were applied to understand the groundwater chemistry of the aquifer. Findings of the correlation matrix were strengthened by the factor analysis, and this shows that salinity is mainly caused by magnesium salts as compared to calcium salts in the aquifer. The problem of salinization seems mainly compounded by the contamination of the shallow aquifers by the recharging water. High factor loading of total alkalinity and bicarbonates indicates that total alkalinity was mainly due to carbonates and bicarbonates of sodium. The concentration of F(-) was found more in the deep aquifer than the shallow aquifer. Further, only a few groundwater samples lie below the permissible limit of F(-), and this indicates a risk of dental caries in the populace of the study area. The present study indicates that regular monitoring of groundwater is an important step to avoid human health risks and to assess its quality for various ecological purposes.

  8. Land-use types and soil chemical properties influence soil microbial communities in the semiarid Loess Plateau region in China.

    PubMed

    Tian, Qin; Taniguchi, Takeshi; Shi, Wei-Yu; Li, Guoqing; Yamanaka, Norikazu; Du, Sheng

    2017-03-28

    Similar land-use types usually have similar soil properties, and, most likely, similar microbial communities. Here, we assessed whether land-use types or soil chemical properties are the primary drivers of soil microbial community composition, and how changes in one part of the ecosystem affect another. We applied Ion Torrent sequencing to the bacterial and fungal communities of five different land-use (vegetation) types in the Loess Plateau of China. We found that the overall trend of soil quality was natural forest > plantation > bare land. Dominant bacterial phyla consisted of Proteobacteria (42.35%), Actinobacteria (15.61%), Acidobacteria (13.32%), Bacteroidetes (8.43%), and Gemmatimonadetes (6.0%). The dominant fungi phyla were Ascomycota (40.39%), Basidiomycota (38.01%), and Zygomycota (16.86%). The results of Canonical Correspondence Analysis (CCA) and Redundancy Analysis (RDA) based on land-use types displayed groups according to the land-use types. Furthermore, the bacterial communities were mainly organized by soil organic carbon (SOC). The fungal communities were mainly related to available phosphorus (P). The results suggested that the changes of land use type generated changes in soil chemical properties, controlling the composition of microbial community in the semiarid Loess Plateau region. The microbial community could be an indicator for soil quality with respect to ecological restoration.

  9. Land-use types and soil chemical properties influence soil microbial communities in the semiarid Loess Plateau region in China

    PubMed Central

    Tian, Qin; Taniguchi, Takeshi; Shi, Wei-Yu; Li, Guoqing; Yamanaka, Norikazu; Du, Sheng

    2017-01-01

    Similar land-use types usually have similar soil properties, and, most likely, similar microbial communities. Here, we assessed whether land-use types or soil chemical properties are the primary drivers of soil microbial community composition, and how changes in one part of the ecosystem affect another. We applied Ion Torrent sequencing to the bacterial and fungal communities of five different land-use (vegetation) types in the Loess Plateau of China. We found that the overall trend of soil quality was natural forest > plantation > bare land. Dominant bacterial phyla consisted of Proteobacteria (42.35%), Actinobacteria (15.61%), Acidobacteria (13.32%), Bacteroidetes (8.43%), and Gemmatimonadetes (6.0%). The dominant fungi phyla were Ascomycota (40.39%), Basidiomycota (38.01%), and Zygomycota (16.86%). The results of Canonical Correspondence Analysis (CCA) and Redundancy Analysis (RDA) based on land-use types displayed groups according to the land-use types. Furthermore, the bacterial communities were mainly organized by soil organic carbon (SOC). The fungal communities were mainly related to available phosphorus (P). The results suggested that the changes of land use type generated changes in soil chemical properties, controlling the composition of microbial community in the semiarid Loess Plateau region. The microbial community could be an indicator for soil quality with respect to ecological restoration. PMID:28349918

  10. Dimethylamine as a major alkyl amine species in particles and cloud water: Observations in semi-arid and coastal regions

    PubMed Central

    Youn, J.-S.; Crosbie, E.; Maudlin, L.C.; Wang, Z.; Sorooshian, A.

    2016-01-01

    Aerosol and cloud water measurements of dimethylamine (DMA), the most abundant amine in this study, were conducted in semi-arid (Tucson, Arizona) and marine (Nucleation in California Experiment, NiCE; central coast of California) areas. In both regions, DMA exhibits a unimodal aerosol mass size distribution with a dominant peak between 0.18 and 0.56 μm. Particulate DMA concentrations increase as a function of marine biogenic emissions, sulfate, BVOC emissions, and aerosol-phase water. Such data supports biogenic sources of DMA, aminium salt formation, and partitioning of DMA to condensed phases. DMA concentrations exhibit positive correlations with various trace elements and most especially vanadium, which warrants additional investigation. Cloud water DMA levels are enhanced significantly during wildfire periods unlike particulate DMA levels, including in droplet residual particles, due to effective dissolution of DMA into cloud water and probably DMA volatilization after drop evaporation. DMA:NH+4 molar ratios peak between 0.18 and 1.0 μm depending on the site and time of year, suggesting that DMA competes better with NH3 in those sizes in terms of reactive uptake by particles. PMID:26807039

  11. Characterization of the deforestation effect in a semi-arid region by the use of satellite images

    NASA Astrophysics Data System (ADS)

    Benhanifia, Khatir; Haddouche, Driss; Smahi, Zakaria; Bensaid, Abdelkrim; Hamimed, Abderrahmane

    2004-02-01

    In Algeria, arid and semi-arid regions occupy over than 95% of whole territory. Forests in the semi arid zone constitutes a front face to the advance of the desert towards northern sides. Like in other regions of the world, deforestation phenomenon have a serious consequences on the fragile ecosystem. Severe continuous drought, fires, pasture, insects as well as the absence of a clear forest politics are so many factors that reduced forest areas in this country. However, the conservation of this patrimony must be a priority of any regional development project. This paper describes an evaluating study of the deforestation impact on forests in the region of Djelfa situated in the Saharian Atlas using multitemporal satellite remote sensing data. In order to establish a forest change map, a methodology based on the comparison between normalized difference vegetation indexes (NDVI) generated from satellite images was adopted. For this purpose, a pair of Landsat and (ETM+) images acquired over the region on April 11th, 1987 and march 24th, 2001 have been used. Until being processed, data used have been geometrically and atmospherically corrected. Then, an (NDVI) have been produced for each date. Resulting from compared (NDVI) image presents the forest change map in the study area. Radiometric values of resulting image have been regrouped into three classes according to change types as follow : Increased radiometry = more active vegetation Decreased radiometry = deterioration in vegetation activity Non changed areas = Non changed Investigations made on the terrain permitted to interpret many causes of detected evolutions. Regressive changes were considerable and demonstrates however, the degradation effect on the vegetation state. Some of regressed radiometry are related to forest fires that affected the region in 1994. Almost of regressive changes are due to a deterioration of vegetation caused by multiple factors. Drought, deceases, pasture and infection are considered

  12. Development of a Semi-Arid, Site-Specific Flash Flood Forecasting System for the Western Region: Results, Insights and Way Forward

    NASA Astrophysics Data System (ADS)

    Yatheendradas, S.; Gupta, H.; Wagener, T.; Unkrich, C.; Goodrich, D.; Schaffner, M.

    2006-12-01

    An increasingly drier and more variable climate trend has significantly increased the incidence of intense (extreme) precipitation events during the 20th century. This has led to a continuous growth of extreme-flood- event losses, despite the widespread problem of water scarcity. In semi-arid regions, the extremely localized and intense summertime convective storm systems cause 'short-fused' flash floods, often result in significant risk to life and property. These arid/semi-arid regions have significant coverage, currently spanning approximately one-third of the earth's surface, and possibly spanning more in the future, for example due to current global warming. The short spatial and temporal extents of flash-floods and the highly complex nature of semi-arid hydrology make the subsequent predictions extremely difficult. Current NWS flash-flood predictions and warnings are based either on usually lumped humid region hydrology models, or on areal rain averages translated to experience-based guidelines. To improve the flash-flood predictive capability to be more `site-specific', an established event-based semi-arid rainfall-runoff model KINEROS2 was modified to allow for the continuous simulation of the basin response driven by high-resolution radar precipitation measurements in an uncertainty framework. The model contains process descriptions required to represent semi-arid and arid regions, including a dynamic infiltration algorithm and the ability to account for channel transmission losses. This forecasting system has been made operational at the Tucson NWS office. This talk focuses on the results from the sophisticated multi-objective distributed model calibration framework developed and used on the operational forecast points which are also burn recovery basins, along with the lessons learned, and the possible future directions.

  13. Spatiotemporal Variability of Mountain Block Recharge in Three Semiarid Watersheds along the U.S.-Mexico Border Region

    NASA Astrophysics Data System (ADS)

    Robles-Morua, A.; Vivoni, E. R.; Mascaro, G.; Dominguez, F.; Rivera-fernandez, E. R.

    2015-12-01

    Groundwater recharge in semiarid mountains of the western U.S. remains a critical component of the regional water balance and has significant repercussions on water resources management, in particular during periods of drought. The bimodal distribution of annual precipitation in the southwest United States and northwest Mexico present a challenge as differential climate impacts during the winter and summer seasons are not currently well understood. In this work, we focus on the predictions of Mountain Block Recharge (MBR) using precipitation forcing from a reanalysis product, regional climate model-based precipitation products and available ground observations. MBR estimates in the Santa Cruz, San Pedro and Sonora River basins (>40,000 km2) are compared along a north to south gradient crossing the U.S.-Mexico border. As a result of the influence of the North American monsoon, the impact of seasonality in each of these systems is evaluated. Simulated precipitation fields under historical (1991-2000) conditions and climate change (2031-2040 and 2070-2080) scenarios are compared at resolutions of 10-km and 35-km as generated from the Weather Research and Forecast (WRF) model using boundary conditions from two general circulation models (MPI-ECHAM and HadCM3). Mountain subbasins to apply a seasonal MBR method were delineated using a threshold in terrain slope that matched official boundaries of known aquifers in these transboundary watersheds. We evaluated the MBR outcomes from the various precipitation products to quantify biases involved in the historical estimates and to inform groundwater management on the uncertainties inherent in future projections. We also inspect the variability of MBR across pluvial and drought periods lasting several years. Seasonal comparisons across a north to south spatial gradient yield a valuable assessment on the impacts of climate change on MBR for important basins in the U.S.-Mexico border region.

  14. Changes in labile soil organic matter fractions following land use change from monocropping to poplar-based agroforestry systems in a semiarid region of Northeast China.

    PubMed

    Mao, Rong; Zeng, De-Hui; Li, Lu-Jun; Hu, Ya-Lin

    2012-11-01

    Labile fractions of soil organic matter (SOM) respond rapidly to land management practices and can be used as a sensitive indicator of changes in SOM. However, there is little information about the effect of agroforestry practices on labile SOM fractions in semiarid regions of China. In order to test the effects of land use change from monocropping to agroforestry systems on labile SOM fractions, we investigated soil microbial biomass C (MBC) and N, particulate organic matter C (POMC) and N (POMN), as well as total organic C (TOC) and total N (TN) in the 0- to 15-cm and the 15- to 30-cm layers in 4-year-old poplar-based agroforestry systems and adjoining monocropping systems with two different soil textures (sandy loam and sandy clay loam) in a semiarid region of Northeast China. Our results showed that poplar-based agroforestry practices affected soil MBC, POMC, and POMN, albeit there was no significant difference in TOC and TN. Agroforestry practices increased MBC, POMC, and POMN in sandy clay loam soils. However, in sandy loam soils, agroforestry practices only increased MBC and even decreased POMC and POMN at the 0- to 15-cm layer. Our results suggest that labile SOM fractions respond sensitively to poplar-based agroforestry practices and can provide early information about the changes in SOM in semiarid regions of Northeast China and highlight that the effects of agroforestry practices on labile SOM fractions vary with soil texture.

  15. Quantifying the reliability of four global datasets for drought monitoring over a semiarid region

    NASA Astrophysics Data System (ADS)

    Katiraie-Boroujerdy, Pari-Sima; Nasrollahi, Nasrin; Hsu, Kuo-lin; Sorooshian, Soroosh

    2016-01-01

    Drought is one of the most relevant natural disasters, especially in arid regions such as Iran. One of the requirements to access reliable drought monitoring is long-term and continuous high-resolution precipitation data. Different climatic and global databases are being developed and made available in real time or near real time by different agencies and centers; however, for this purpose, these databases must be evaluated regionally and in different local climates. In this paper, a near real-time global climate model, a data assimilation system, and two gridded gauge-based datasets over Iran are evaluated. The ground truth data include 50 gauges from the period of 1980 to 2010. Drought analysis was carried out by means of the Standard Precipitation Index (SPI) at 2-, 3-, 6-, and 12-month timescales. Although the results show spatial variations, overall the two gauge-based datasets perform better than the models. In addition, the results are more reliable for the western portion of the Zagros Range and the eastern region of the country. The analysis of the onsets of the 6-month moderate drought with at least 3 months' persistence indicates that all datasets have a better performance over the western portion of the Zagros Range, but display poor performance over the coast of the Caspian Sea. Base on the results of this study, the Modern-Era Retrospective Analysis for Research and Applications (MERRA) dataset is a preferred alternative for drought analysis in the region when gauge-based datasets are not available.

  16. Distinct Leishmania infantum Strains Circulate in Humans and Dogs in the Emilia-Romagna Region, Northeastern Italy.

    PubMed

    Rugna, Gianluca; Carra, Elena; Corpus, Francesco; Calzolari, Mattia; Salvatore, Daniela; Bellini, Romeo; Di Francesco, Antonietta; Franceschini, Erica; Bruno, Antonella; Poglayen, Giovanni; Varani, Stefania; Vitale, Fabrizio; Merialdi, Giuseppe

    2017-03-16

    Human leishmaniasis is an emerging problem in Italy and is on the increase in the Emilia-Romagna region, northeastern part of the country. Nevertheless, studies dealing with the molecular characterization of Leishmania spp. circulating in these areas are limited. In the present work, we explored the genetic polymorphism of Leishmania isolates from 28 cases of canine leishmaniasis and three cases of human visceral leishmaniasis (VL), which occurred in 2013-2014 in the Emilia-Romagna region. The characterization was carried out in comparison with nine human isolates of Leishmania from other VL endemic Italian regions and two reference strains. Nucleic acid from 31 Leishmania-positive phlebotomine sandfly pools, sampled in 2012-2013 in the Emilia-Romagna region, were also evaluated. DNA amplification and sequencing of the ribosomal internal transcribed spacer-1 and of a repetitive nuclear region on chromosome 31 were carried out for genotyping. Two size polymorphic targets were also analyzed by PCR, the cpb E/F-gene and the k26-gene. Altogether, the analysis showed the circulation of different Leishmania infantum genotypes in the Emilia-Romagna region: two genotypes found in dogs from public kennels were similar to VL isolates from other Italian regions, whereas a third genotype was detected in VL cases of the Emilia-Romagna region and in all but one of the sandfly pools. The combined molecular tools applied in this study can constitute a helpful support for parasite tracking (e.g., in outbreak investigations) and for a better understanding of the epidemiological evolution of leishmaniasis in northeastern Italy.

  17. Regional impacts of urbanization on stream channel geometry: A case study in semiarid southern California

    NASA Astrophysics Data System (ADS)

    Taniguchi, Kristine T.; Biggs, Trent W.

    2015-11-01

    Urbanization often increases storm runoff, peak discharges and rates of stream channel erosion. Coastal California has experienced rapid urbanization over the past several decades and has the potential for stream channel degradation. Several counties in California have implemented Hydromodification Management Plans (HMPs) to protect channels from erosion, but few studies have quantified the impact of urbanization on channel geometry in diverse geological settings at the county scale. A synoptic survey of field sites (N = 56) by the California Environmental Data Exchange Network (CEDEN) and additional field surveys (N = 24) were used to develop regional hydraulic geometry curves relating bankfull cross-sectional area (Axs), width (w), mean depth (d), and discharge (Qbf) to watershed area (Aw) in San Diego County. Regional curves were compared for urban and reference sites and to other regional curves developed for southern California. Multiple regression models were used to identify dominant watershed and channel controls on geometry, including Aw, percent impervious cover (I%), mean annual precipitation, underlying geology, longitudinal slope, hydrologic soil group, and channel particle size. For the reference streams, regional curves were statistically significant for w and Axs (p < 0.05). The regional curves for urban channels (I% > 20%) had significantly larger w, d, Axs, and Qbf for a given watershed size. A majority (68%) of the urban channels and 78% of the small urban channels (Aw < 10 km2) were enlarged. Enlargement of channels in small watersheds disrupted the correlation between Aw and bankfull dimensions, and I% was the only significant predictor of channel geometry in urban watersheds. Channel response differed by channel substrate: sand-bedded channels incised and experienced extreme enlargement of up to 115 × the Axs of reference sites, while gravel-bedded channels widened and showed less enlargement (< 7 × reference Axs). Diverse channel responses

  18. Hydrologic cycle and dynamics of aquatic macrophytes in two intermittent rivers of the semi-arid region of Brazil.

    PubMed

    Pedro, F; Maltchik, L; Bianchini, I

    2006-05-01

    The dynamics of aquatic macrophytes in intermittent rivers is generally related to the characteristics of the resistance and resilience of plants to hydrologic disturbances of flood and drought. In the semi-arid region of Brazil, intermittent rivers and streams are affected by disturbances with variable intensity, frequency, and duration throughout their hydrologic cycles. The aim of the present study is to determine the occurrence and variation of biomass of aquatic macrophyte species in two intermittent rivers of distinct hydrologic regimes. Their dynamics were determined with respect to resistance and resilience responses of macrophytes to flood and drought events by estimating the variation of biomass and productivity throughout two hydrologic cycles. Twenty-one visits were undertaken in the rewetting, drying, and drought phases in a permanent puddle in the Avelós stream and two temporary puddles in the Taperoá river, state of Paraíba, Northeast Brazil. The sampling was carried out by using the square method. Floods of different magnitudes occurred during the present study in the river and in the stream. The results showed that floods and droughts are determining factors in the occurrence of macrophytes and in the structure of their aquatic communities. The species richness of the aquatic macrophyte communities was lower in the puddles of the river and stream subject to flood events, when compared to areas where the run-off water is retained. At the beginning of the recolonization process, the intensity of the floods was decisive in the productivity and biomass of the aquatic macrophytes in the Taperoá river and the Avelós stream. In intermediate levels of disturbance, the largest values of productivity and biomass and the shortest time for starting the recolonization process occurred.

  19. Effects of different agricultural managements in soil microbial community structure in a semi-arid Mediterranean region.

    NASA Astrophysics Data System (ADS)

    García-Orenes, Fuensanta; Morugan, Alicia; Mataix-Solera, Jorge; Scow, Kate

    2013-04-01

    Agriculture has been practiced in semi-arid Mediterranean regions for 10.000 years and in many cases these practices have been unsuitable causing land degradation for millennium and an important loss of soil quality. The land management can provide solutions to find the best agricultural practices in order to maintain the soil quality and get a sustainable agriculture model. Microbiological properties are the most sensitive and rapid indicators of soil perturbations and land use managements. The study of microbial community and diversity has an important interest as indicators of changes in soil quality. The main objective of this work was to asses the effect of different agricultural management practices in soil microbial community (evaluated as abundance of phospholipid fatty acids, PLFA). Four different treatments were selected, based on the most commonly practices applied by farmers in the study area, "El Teularet Experimental Station", located at the Enguera Range in the southern part of the Valencia province (eastern Spain). These treatments were: a) ploughing, b) herbicides c) mulch, using the types applied by organic farmers to develop a sustainable agriculture, such as oat straw and d) control that was established as plot where the treatment was abandonment after farming. An adjacent area with the same type of soil, but with natural vegetation was used as a standard or reference high quality soil. Soil samples were taken to evaluate the changes in microbial soil structure, analysing the abundance of PLFA. The results showed a major content of total PLFA in soils treated with oats straw, being these results similar to the content of PLFA in the soil with natural vegetation, also these soils were similar in the distribution of abundance of different PLFA studied. However, the herbicide and tillage treatments showed great differences regarding the soil used as reference (soil under natural vegetation).

  20. High Prevalence and Onward Transmission of Non-Pandemic HIV-1 Subtype B Clades in Northern and Northeastern Brazilian Regions

    PubMed Central

    Divino, Flavia; de Lima Guerra Corado, Andre; Gomes Naveca, Felipe; Stefani, Mariane M. A.; Bello, Gonzalo

    2016-01-01

    The Human immunodeficiency virus type-1 (HIV-1) epidemic in Brazil is mainly driven by the subtype B pandemic lineage (BPANDEMIC), while Caribbean non-pandemic subtype B clades (BCAR) seem to account for a very low fraction of HIV-infections in this country. The molecular characteristics of the HIV-1 subtype B strains disseminated in the Northern and Northeastern Brazilian regions, however, have not been explored so far. In this study, we estimate the prevalence of the HIV-1 BPANDEMIC and BCAR clades across different Brazilian regions and we reconstruct the spatiotemporal dynamics of dissemination of the major Brazilian BCAR clades. A total of 2,682 HIV-1 subtype B pol sequences collected from 21 different Brazilian states from the five country regions between 1998 and 2013 were analyzed. Maximum Likelihood phylogenetic analyses revealed that the BCAR strains reached 16 out 21 Brazilian states here analyzed. The BCAR clades comprise a low fraction (<10%) of subtype B infections in most Brazilian states analyzed, with exception of Roraima (41%), Amazonas (14%) and Maranhão (14%). Bayesian phylogeographic analyses indicate that BCAR strains originally from the Hispaniola and Trinidad and Tobago were introduced at multiple times into different states from all Brazilian regions and a few of those strains, probably introduced into Roraima, Maranhão and São Paulo between the late 1970s and the early 1980s, established secondary outbreaks in the Brazilian population. These results support that the HIV-1 subtype B epidemics in some Brazilian states from the Northern and Northeastern regions display a unique molecular pattern characterized by the high prevalence of BCAR lineages, which probably reflects a strong epidemiological link with the HIV-1 epidemics in the Caribbean region. PMID:27603317

  1. Drainage network extraction of Brazilian semiarid region with potential flood indication areas

    NASA Astrophysics Data System (ADS)

    Rosim, Sergio; de Freitas Oliveira, João. Ricardo; de Oliveira Ortiz, Jussara; Cuellar, Miguel Zanic; Jardim, Alexandre Copertino

    2014-10-01

    This region has the particularity of, at the same time, coexisting with sporadic floods and scarcity of water. This situation requires complex studies involving water resources based on runoff of rain waters and on the courses of the rivers. For the extraction of drainage was carried out by using of the system for hydrological modeling treatment TerraHidro, developed by INPE's Image Processing Division. This system uses the PFS method for extraction of drainage, which has provided good results, enabling the reduction of the time spent on manual editing of drainage errors. TerraHidro has a tool called Height Above the Nearest Drainage (HAND) which gives information on potential flood areas. Elevation data were used in the Aster GDEM with spatial resolution of 30 meters for drainage extraction. A qualitative comparison was performed between drainage extracted by TerraHidro and drainage manually extracted by a specialist.

  2. Violence against Women by Their Intimate Partners in Shahroud in Northeastern Region of Iran

    PubMed Central

    Hajian, Sepideh; Vakilian, Katayon; Najm-abadi, Khadijeh Mirzaii; Hajian, Parastoo; Jalalian, Mehrdad

    2014-01-01

    Background: Violence against women is one of the worst consequences of cultural, political, and socio-economic inequalities between men and women. Intimate Partner Violence (IPV) has been identified as an important cause of morbidity from multiple mental, physical, sexual, and reproductive health outcomes. Nonetheless, the prevalence and related factors of this international problem have not been investigated extensively in some parts of the world. The aims of this research were to determine the prevalence of physical and mental violence perpetrated by men against their intimate partners and to assess the associated factors of partner violence among women in Shahroud in northeastern region of Iran in 2010. Methods: This Cross-Sectional study was conducted in Shahroud, in northeast of Iran in 2010. Cluster sampling was done from primary health service institutions, universities, public schools and governmental organizations throughout the city and six hundred married women completed the study. A structured questionnaire with 34 items was designed in three parts to assess the physically (10 items) and mentally (15 items) violent acts by a current intimate male partner and identify collative behaviors (9 items) of victims. The Logistic regression analysis was applied to determine the net effect of background variables on the IPV occurrence within the past year. Results: About 20% of the participants experienced at least one type of physical violence. Increased risk of physical violence was positively associated with the younger age of the couple (OR=3.08, P< 0.05), lower education (OR=2.28, P<0.01) and having a semi-manual skilled occupation of husband (OR=3.62, P<0.05), husband’s heavy cigarette smoking (OR=2.62, P<0.01), and his drug abuse (OR=2.1, P<0.05). About 85% of the women had experienced mental harassment within the past twelve months. Logistic Regression Analysis found that lower education (OR=3.06, P<0.01) and having semi-manual skilled occupation (OR=3

  3. Carbonaceous aerosol over semi-arid region of western India: Heterogeneity in sources and characteristics

    NASA Astrophysics Data System (ADS)

    Sudheer, A. K.; Aslam, M. Y.; Upadhyay, M.; Rengarajan, R.; Bhushan, R.; Rathore, J. S.; Singh, S. K.; Kumar, S.

    2016-09-01

    Carbonaceous species (elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC)) and water-soluble inorganic species (Na+, NH4+, K+, Ca2 +, Mg2 +, Cl-, NO3-, SO42 -) in PM10 and PM2.5 from Ahmedabad and Jodhpur (urban and semi-urban locations, respectively) in western India were measured during May-September, 2011. Stable isotope composition of carbonaceous aerosol (δ13C of TC) in PM10 samples was also determined. Average EC concentration in PM10 at Ahmedabad was 1 μg m- 3 (range: 0.34 to 3.4 μg m- 3), almost 80% of which remained in PM2.5. Similarly, 70% of EC in PM10 (average: 0.9 μg m- 3) resided in PM2.5 at Jodhpur. Average OC concentration at Ahmedabad was 6.4 μg m- 3 and 52% of this was found in PM2.5. On the contrary, OC concentration at Jodhpur was 40 μg m- 3, 80% of which was found in coarse particles contributing substantially to aerosol mass. δ13C of TC (average: - 27.5‰, range: - 29.6 to - 25.8‰) along with WSOC/EC ratio shows an increasing trend at Jodhpur suggesting the possibility of aging of aerosol, since aging results in enrichment of heavier isotope. OC and WSOC show significant correlations with K+ and not with EC, indicating biogenic origin of OC. Different size distributions are also exhibited by WSOC at the two stations. On the other hand, δ13C exhibits an inverse trend with sea-salt constituents at Ahmedabad, indicating the influence of air masses transported from the western/south-western region on carbonaceous aerosol. These results suggest that a strong heterogeneity exists in the sources of carbonaceous aerosol over this region and potential sources of non-combustion emissions such as bio-aerosol that need further investigation.

  4. Effects of harbor activities on sediment quality in a semi-arid region in Brazil.

    PubMed

    Moreira, Lucas B; Castro, Ítalo B; Hortellani, Marcos A; Sasaki, Silvio T; Taniguchi, Satie; Petti, Mônica A V; Fillmann, Gilberto; Sarkis, Jorge E S; Bícego, Márcia C; Costa-Lotufo, Leticia V; Abessa, Denis M S

    2017-01-01

    Tropical marine environments are rich in biodiversity and the presence of harbor activities in these areas can harm the coastal ecosystems. In this study, we assessed sediment quality of two harbors from a tropical region in Brazil by applying multiple lines-of-evidence approach. This approach included the integration of results on: (1) grain size, organic matter, organic carbon, nitrogen, phosphorus, trace metals, polycyclic aromatic hydrocarbons, linear alkylbenzenes, and tributyltin; (2) acute toxicity of whole sediments and chronic toxicity of liquid phases; and (3) benthic community descriptors. Our results revealed that the main contaminants detected in sediments from Mucuripe and Pecém Harbors were chromium, copper, nitrogen, zinc, and tributyltin. These toxicants arise from typical harbor activities. However, the changes in benthic composition and structure appear to depend on a combination of physical impacts, such as the deposition of fine sediments and the toxic potential of contaminants, especially in Mucuripe. Thus, apart from toxicants physical processes are important in describing risks. This information may assist in management and conservation of marine coastal areas.

  5. Ecological restoration and effect investigation of a river wetland in a semi-arid region, China

    NASA Astrophysics Data System (ADS)

    Xu, S.; Jiang, X.; Liu, Y.; Fu, Y.; Zhao, Q.

    2015-05-01

    River wetlands are heavily impacted by human intervention. The degradation and loss of river wetlands has made the restoration of river ecosystems a top priority. How to rehabilitate rivers and their services has been a research focus. The main goal of it is to restore the river wetland ecosystems with ecological methods. The Gudong River was selected as a study site in Chaoyang city in this study. Based on the analysis of interference factors in the river wetland degradation, a set of restoration techniques were proposed and designed for regional water level control, including submerged dikes, ecological embankments, revegetation and dredging. The restoration engineering has produced good results in water quality, eco-environment, and landscape. Monthly reports of the Daling River show that the water quality of Gudong River was better than Grade III in April 2013 compared with Grade V in May 2012. The economic benefit after restoration construction is 1.71 million RMB per year, about 1.89 times that before. The ratio of economic value, social value and eco-environmental value is 1:4:23.

  6. Root density of cherry trees grafted on prunus mahaleb in a semi-arid region

    NASA Astrophysics Data System (ADS)

    Paltineanu, Cristian; Septar, Leinar; Gavat, Corina; Chitu, Emil; Oprita, Alexandru; Moale, Cristina; Lamureanu, Gheorghe; Vrinceanu, Andrei

    2016-07-01

    Root density was investigated using the trench method in a cherry (Prunus avium grafted on Prunus mahaleb) orchard with clean cultivation in inter-rows and in-row. Trenches of 1 m width and 1.2 m depth were dug up between neighbouring trees. The objectives of the paper were to clarify the spatial distribution of root density of cherry trees under the soil and climate conditions of the region to expand knowledge of optimum planting distance and orchard management for a broad area of chernozems. Some soil physical properties were significantly worsened in inter-rows versus in-row, mainly due to soil compaction, and there were higher root density values in in-row versus inter-rows. Root density decreased more intensely with soil depth than with distance from trees. The pattern of root density suggests that the cherry tree density and fruit yield could be increased. However, other factors concerning orchard management and fruit yield should also be considered. The results obtained have a potential impact to improve irrigation and fertilizer application by various methods, considering the soil depth and distance from trees to wet soil, in accordance with root development.

  7. Insights for empirically modeling evapotranspiration influenced by riparian and upland vegetation in semiarid regions

    USGS Publications Warehouse

    Bunting, Daniel P.; Kurc, Shirley A.; Glenn, Edward P.; Nagler, Pamela L.; Scott, Russell L.

    2014-01-01

    Water resource managers aim to ensure long-term water supplies for increasing human populations. Evapotranspiration (ET) is a key component of the water balance and accurate estimates are important to quantify safe allocations to humans while supporting environmental needs. Scaling up ET measurements from small spatial scales has been problematic due to spatiotemporal variability. Remote sensing products provide spatially distributed data that account for seasonal climate and vegetation variability. We used MODIS products [i.e., Enhanced Vegetation Index (EVI) and nighttime land surface temperatures (LSTn)] to create empirical ET models calibrated using measured ET from three riparian-influenced and two upland, water-limited flux tower sites. Results showed that combining all sites introduced systematic bias, so we developed separate models to estimate riparian and upland ET. While EVI and LSTn were the main drivers for ET in riparian sites, precipitation replaced LSTn as the secondary driver of ET in upland sites. Riparian ET was successfully modeled using an inverse exponential approach (r2 = 0.92) while upland ET was adequately modeled using a multiple linear regression approach (r2 = 0.77). These models can be used in combination to estimate ET at basin scales provided each region is classified and precipitation data is available.

  8. Mashhad Wise Water Forum: a path to sustainable water resources management in a semi-arid region of Iran

    NASA Astrophysics Data System (ADS)

    Tabatabaee, Seyyed Alireza; Neyshaboori, Shahnaz; Basirat, Ali; Tavakoli Aminiyan, Samaneh; Mirbehrooziyan, Ahmad; Sakhdari, Hossein; Shafiei, Mojtaba; Davary, Kamran

    2016-04-01

    Water is key to sustainable development especially in semi-arid regions in which the main source of water provision is groundwater. Water has value from a social, economic and environmental perspective and is required to be managed within a sound, integrated socio-economic and environmental framework. Mashhad, the second big city in Iran, has been faced with rapid growth rates of population and economic activities. The groundwater in Mashhad basin has been overexploited to meet the increasing trend of water demand during the past 20 years. Consequently, the region has faced with water scarcity and water quality problems which originates from inefficient use and poor management. To tackle the water issue on a durable basis, within the economic, ecological, and political constraints (i.e. the integrated water resources management, IWRM concept), a Non-Governmental Organization (NGO), named as Mashhad Wise Water Forum (MWWF), has been established in 2013 that encompasses contribution of experts from academia, industry, and governmental policy-makers. The MWWF considers the UN-Water IWRM spiral conceptual model (which contains four stages: Recognizing and identifying; Conceptualizing; Coordinating and planning; Implementing, Monitoring and Evaluating) by implicating participatory water management (water users' involvement) methods in Mashhad basin. Furthermore, the MWWF has planned to look at all dimensions of water crisis (i.e. physical, economic, policy and institutional) particularly institutional dimension by gathering all stockholders, beneficiaries and experts in different parts of water policy making in Mashhad basin. The MWWF vision for Mashhad basin is achieving to sustainable equilibrium of water resources and consumptions in the basin by the prospect to 2040 year. So far, the MWWF has tried to understand and deal with regional diversity in legal systems as well as conflicts between private interests and public welfare in water allocation and management. At

  9. Temporal and spectral characteristics of aerosol optical depths in a semi-arid region of southern India.

    PubMed

    Kumar, K Raghavendra; Narasimhulu, K; Reddy, R R; Gopal, K Rama; Reddy, L Siva Sankara; Balakrishnaiah, G; Moorthy, K Krishna; Babu, S Suresh

    2009-04-01

    The spectral and temporal variations of aerosol optical depths (AOD) observed over Anantapur (a semi-arid region) located in the Southern part of India are investigated by analyzing the data obtained from a Multiwavelength Solar Radiometer (MWR) during January 2005-December 2006 (a total of 404 clear-sky observations) using the Langley technique. In this paper, we highlighted the studies on monthly, seasonal and spectral variations of aerosol optical depth and their implications. The results showed seasonal variation with higher values during pre-monsoon (March-May) and lower in the monsoon (June-November) season at all wavelengths. The pre-monsoon increase is found to be due to the high wind speed producing larger amounts of wind-driven dust particles. The post-monsoon (December-February) AOD values decrease more at higher wavelengths, indicating a general reduction in the number of bigger particles. Also during the post-monsoon, direction of winds in association with high or low pressure weather systems and the air brings more aerosol content to the region which is surrounded by a number of cement plants, lime kilns, slab polishing and brick making units. The quantity of AOD values in pre-monsoon is higher (low during post-monsoon) for wavelength, such as shortwave infrared (SWIR) or near infrared (NIR), which shows that coarse particles contribute more compare with the sub-micron particles. The composite aerosols near the surface follow suit with the share of the accumulation mode to the total mass concentration decreasing from approximately 70% to 30% from post-monsoon to pre-monsoon. Coarse mode particle loading observed to be high during pre-monsoon and accumulation mode particles observed to be high during post-monsoon. The backward trajectories at three representative altitudes with source point at the observing site indicate a possible transport from the outflow regions into Bay of Bengal, southern peninsular India and Arabian Sea. The temporal variations

  10. Ambient nitrogen dioxide and sulfur dioxide concentrations over a region of natural gas production, Northeastern British Columbia, Canada

    NASA Astrophysics Data System (ADS)

    Islam, S. M. Nazrul; Jackson, Peter L.; Aherne, Julian

    2016-10-01

    The Peace River district of Northeastern British Columbia, Canada is a region of natural gas production that has undergone rapid expansion since 2005. In order to assess air quality implications, Willems badge passive diffusive samplers were deployed for six two-week exposure periods between August and November 2013, at 24 sites across the region to assess the ambient concentration of nitrogen dioxide (NO2) and sulfur dioxide (SO2). The highest concentrations of both species (NO2: 9.1 ppb, SO2: 1.91 ppb) during the whole study period (except the 1st exposure period), were observed in Taylor (Site 14), which is consistent with its location near major industrial sources. Emissions from industrial activities, and their interaction with meteorology and topography, result in variations in atmospheric dispersion that can increase air pollution concentrations in Taylor. However, relatively high concentrations of NO2 were also observed near the center of Chetwynd (site F20), indicating the importance of urban emissions sources in the region as well. Observations of both species from the other study sites document the spatial variability and show relatively high concentrations near Fort St. John and Dawson Creek, where unconventional oil and gas development activities are quite high. Although a few sites in Northeastern British Columbia recorded elevated concentrations of NO2 and SO2 during this investigation, the concentrations over the three-month period were well below provincial annual ambient air quality objectives. Nonetheless, given the limited observations in the region, and the accelerated importance of unconventional oil and gas extraction in meeting energy demands, it is imperative that monitoring networks are established to further assess the potential for elevated ambient concentrations associated with industrial emissions sources in the Peace River region.

  11. Reforestation and landscape reconstruction in gypsum mine area from the semiarid region of NE Brazil

    NASA Astrophysics Data System (ADS)

    Bittar, S. M. B.; Straaten, P. V.; de Araujo Vieura Santos, M. de Fatima; Agra Bezerra da Silva, Y. J.; da Silva, M.; Saraiva de Melo Pinheiro, T.; Gusmao Didier de Moraes, F.; de Aguiar Accioly, A. M.; Alves de Santana, S. R.; dos Santos, H. A.; de Carvalho, D. M.; de Lima Ferreira, G.; de Carvalho Santos, C.

    2012-04-01

    In the Araripe region, Northeast Brazil, exist the world's second largest reserve of gypsum, estimated at over than one billion tons, which accounts for 95% of the Brazilian production and constitutes an important segment of the regional economy. The gypsum deposit occurs in the Lower Cretaceous Santana Formation of the Araripe basin, which is constituted by siltstones, marls, limestones, shales and gypsum layers. The ore extraction is from an open pit, on simple benches with a height of about 15 meters. Activities in mining operations involve stripping, drilling, loading explosives, blast, fragmentation and block loading / transport. Currently, gypsum mining and processing results in major changes in the landscape (pits and wastes heaps sedimentary rocks and soil mixture), deforestation of the "caatinga" ecosystem for use as firewood in small calcinations, dust pollution and changes in hydrology. To promote environmental remediation of this area, a multidisciplinary research has being done with the aim to support reforestation at the wastes heaps. The study involved the following activities: collection and physical, chemical and mineralogical characterization of mine waste materials; a floristic survey around the mines (botanical identification and measuring physical parameters in 16 plots, in order to identify which species are best suited to the conditions of the substrate at the mine site); an experiment (randomized block design) developed in a greenhouse, where seedlings of various native tree species were grown in a "constructed soil" made up of gypsum waste combined with chicken, goat and cattle manure, aimed to select tree species and soil treatment to be used in a waste heap; and an assessment of water quality for irrigation of the reforestation areas. The waste materials consist of large clayey aggregates, which may present physical/chemical properties unfavorable for plant development. The mineralogy of the sand fraction (> 85% quartz, gypsum and

  12. Land Surface Model and Particle Swarm Optimization Algorithm Based on the Model-Optimization Method for Improving Soil Moisture Simulation in a Semi-Arid Region.

    PubMed

    Yang, Qidong; Zuo, Hongchao; Li, Weidong

    2016-01-01

    Improving the capability of land-surface process models to simulate soil moisture assists in better understanding the atmosphere-land interaction. In semi-arid regions, due to limited near-surface observational data and large errors in large-scale parameters obtained by the remote sensing method, there exist uncertainties in land surface parameters, which can cause large offsets between the simulated results of land-surface process models and the observational data for the soil moisture. In this study, observational data from the Semi-Arid Climate Observatory and Laboratory (SACOL) station in the semi-arid loess plateau of China were divided into three datasets: summer, autumn, and summer-autumn. By combing the particle swarm optimization (PSO) algorithm and the land-surface process model SHAW (Simultaneous Heat and Water), the soil and vegetation parameters that are related to the soil moisture but difficult to obtain by observations are optimized using three datasets. On this basis, the SHAW model was run with the optimized parameters to simulate the characteristics of the land-surface process in the semi-arid loess plateau. Simultaneously, the default SHAW model was run with the same atmospheric forcing as a comparison test. Simulation results revealed the following: parameters optimized by the particle swarm optimization algorithm in all simulation tests improved simulations of the soil moisture and latent heat flux; differences between simulated results and observational data are clearly reduced, but simulation tests involving the adoption of optimized parameters cannot simultaneously improve the simulation results for the net radiation, sensible heat flux, and soil temperature. Optimized soil and vegetation parameters based on different datasets have the same order of magnitude but are not identical; soil parameters only vary to a small degree, but the variation range of vegetation parameters is large.

  13. Too Much or Too Little? Eco-hydrology in Arid and Semi-arid Regions

    NASA Astrophysics Data System (ADS)

    Toch, S. L.

    2009-04-01

    Around the world, disastrous effects of floods and droughts are painful evidence of our continuing struggle between human resource demands and the sustainability of our hydrologic ecosystems. Too much or too little rainfall is often deemed the culprit in these water crises, focusing on water "lacks and needs" instead of exploring the diverse mechanisms of the hydrologic functions and processes that sustain us. Applicable to regions around the world, this unified approach focuses on the connections between our human and ecological qualities, with user friendly concepts and how-to guides backed up by real life experiences. From the poorest parts of Africa to Urban France to the wealthiest state in the USA, examples from surface to groundwater to marine environments demonstrate how the links between vulnerable natural areas, and the basins that they support are integral to the availability, adequacy and accessibility of our drinking water. The interactions of watersheds within our diverse communities can link our resource practices with our human needs, serving as a basis for our ecological health and human well-being. Hydrologic ecosystems provide links to geographic and cultural information traversing physical and social boundaries. This international, community-based project demonstrates how our human resource demands can be managed within ecological constraints. An inter-disciplinary process is used that specifically explores the connections between ecological integrity and the preservation of potable supplies. A monitoring strategy is developed that assesses risk to human health from resource use practices, and explores the similarities and interactions between our human needs and those of the ecosystems in which we all must live together. This work is geared as a reference for groups, individuals and agencies concerned with land use and watershed management, a supplement for interdisciplinary high school through University curriculum, for professional

  14. The potential for biomass to mitigate greenhouse gas emissions in the Northeastern US. Northeast Regional Biomass Program

    SciTech Connect

    Bernow, S.S.; Gurney, K.; Prince, G.; Cyr, M.

    1992-04-01

    This study, for the Northeast Regional Biomass Program (NRBP) of the Coalition of Northeast Governors (CONEG), evaluates the potential for local, state and regional biomass policies to contribute to an overall energy/biomass strategy for the reduction of greenhouse gas releases in the Northeastern United States. Biomass is a conditionally renewable resource that can play a dual role: by reducing emissions of greenhouse gases in meeting our energy needs; and by removing carbon from the atmosphere and sequestering it in standing biomass stocks and long-lived products. In this study we examine the contribution of biomass to the energy system in the Northeast and to the region`s net releases of carbon dioxide and methane, and project these releases over three decades, given a continuation of current trends and policies. We then compare this Reference Case with three alternative scenarios, assuming successively more aggressive efforts to reduce greenhouse gas emissions through strategic implementation of energy efficiency and biomass resources. Finally, we identify and examine policy options for expanding the role of biomass in the region`s energy and greenhouse gas mitigation strategies.

  15. Helicobacter pylori infection among Aborigines (the Orang Asli) in the northeastern region of Peninsular Malaysia.

    PubMed

    Rahim, Amry Abdul; Lee, Yeong Yeh; Majid, Noorizan Abd; Choo, Keng Ee; Raj, Sundramoorthy Mahendra; Derakhshan, Mohammad H; Graham, David Y

    2010-11-01

    Whether the exceptionally low prevalence of Helicobacter pylori (HP) infection reported among Malays is also present among aborigines (the Orang Asli) living in northeastern Peninsular Malaysia is unknown. We studied asymptomatic Orang Asli from settlements situated 210 km from the city of Kota Bharu. The HP infection status was confirmed by a validated serology test. Nineteen percent of 480 Orang Asli tested positive for HP infection. The prevalence was 40.6% in the birth cohort of the 1940s and declined steadily in later cohorts to under 10% among 12-30 year olds. This may be related to the phases of relocation from the jungles into resettlement camps and ultimately into designated villages near rivers. The low prevalence pattern after the 1970s was probably partly a result of improvement in sanitation and hygiene practice in these villages but other unidentified factors may also be operating.

  16. Bathymetric terrain model of the Puerto Rico Trench and the northeastern Caribbean region for marine geological investigations

    USGS Publications Warehouse

    Andrews, Brian D.; ten Brink, Uri S.; Danforth, William W.; Chaytor, Jason D.; Granja Bruña, José-Luis; Llanes Estrada, Pilar; Carbó-Gorosabel, Andrés

    2014-01-01

    Records were obtained for 305 wells and 1 spring in northwestern Lee and southeastern Chatham counties, NorMultibeam bathymetric data collected in the Puerto Rico Trench and northeastern Caribbean region are compiled into a seamless bathymetric terrain model for broad-scale geological investigations of the trench system. These data, collected during eight separate surveys between 2002 and 2013 and covering almost 180,000 square kilometers, are published here in large-format map sheet and digital spatial data. This report describes the common multibeam data collection and processing methods used to produce the bathymetric terrain model and corresponding data-source polygon. Details documenting the complete provenance of the data are provided in the metadata in the Data Catalog section.

  17. Seroprevalence and Spatial Distribution of Toxoplasmosis in Sheep and Goats in North-Eastern Region of Pakistan.

    PubMed

    Ahmed, Haroon; Malik, Ayesha; Arshad, Muhammad; Mustafa, Irfan; Khan, Mobushir Riaz; Afzal, Muhammad Sohail; Ali, Shahzad; Mobeen, Muhammad; Simsek, Sami

    2016-08-01

    Toxoplasmosis is a protozoan disease that is caused by Toxoplasma gondii in livestock and humans. Due to its medical and veterinary importance, it is essential to study the seroprevalence of T. gondii infection among humans and animals in various parts of the world. The major objective of this study was to determine the seroprevalence and spatial distribution of toxoplasmosis in small ruminants (sheep and goats) of north-eastern region, Pakistan. A total of 1,000 animals comprising of sheep (n=470) and goats (n=530) were examined for T. gondii infection by using ELISA. An epidemiological data was collected in the form of questionnaire. A surface has been generated by using method of interpolation in Arc GIS with the help of IDW (inverse distance weight). The results showed higher seroprevalence of T. gondii in goats (42.8%) as compared to sheep (26.2%). The seroprevalence was higher in females as compared to males in all examined ruminants. Similarly, there is a wide variation in the seroprevalence of T. gondii in different breeds of sheep and goats showing higher seroprevalence in Teddy (52.8%) and Damani breed (34.5%) of goat and sheep's, respectively. The geographical and spatial distribution of T. gondii shows that it is widely distributed in different parts of the north-eastern region of Pakistan. Our results suggest widespread environmental contamination with T. gondii oocysts. It suggests us that small ruminants could be a potentially important source of T. gondii infection if their infected meat is consumed undercooked.

  18. Seroprevalence and Spatial Distribution of Toxoplasmosis in Sheep and Goats in North-Eastern Region of Pakistan

    PubMed Central

    Ahmed, Haroon; Malik, Ayesha; Arshad, Muhammad; Mustafa, Irfan; Khan, Mobushir Riaz; Afzal, Muhammad Sohail; Ali, Shahzad; Mobeen, Muhammad; Simsek, Sami

    2016-01-01

    Toxoplasmosis is a protozoan disease that is caused by Toxoplasma gondii in livestock and humans. Due to its medical and veterinary importance, it is essential to study the seroprevalence of T. gondii infection among humans and animals in various parts of the world. The major objective of this study was to determine the seroprevalence and spatial distribution of toxoplasmosis in small ruminants (sheep and goats) of north-eastern region, Pakistan. A total of 1,000 animals comprising of sheep (n=470) and goats (n=530) were examined for T. gondii infection by using ELISA. An epidemiological data was collected in the form of questionnaire. A surface has been generated by using method of interpolation in Arc GIS with the help of IDW (inverse distance weight). The results showed higher seroprevalence of T. gondii in goats (42.8%) as compared to sheep (26.2%). The seroprevalence was higher in females as compared to males in all examined ruminants. Similarly, there is a wide variation in the seroprevalence of T. gondii in different breeds of sheep and goats showing higher seroprevalence in Teddy (52.8%) and Damani breed (34.5%) of goat and sheep’s, respectively. The geographical and spatial distribution of T. gondii shows that it is widely distributed in different parts of the north-eastern region of Pakistan. Our results suggest widespread environmental contamination with T. gondii oocysts. It suggests us that small ruminants could be a potentially important source of T. gondii infection if their infected meat is consumed undercooked. PMID:27658595

  19. Development of the Instructional Model of Reading English Strategies for Enhancing Sophomore Students' Learning Achievements in the Institute of Physical Education in the Northeastern Region of Thailand

    ERIC Educational Resources Information Center

    Whankhom, Prawit; Phusawisot, Pilanut; Sayankena, Patcharanon

    2016-01-01

    The aim of this research is to develop and verify the effectiveness of an instructional model of reading English strategies for students of Mahasarakham Institute of Physical Education in the Northeastern region through survey. Classroom action research techniques with the two groups of sample sizes of 34 sophomore physical students as a control…

  20. The Effects of a Parenting Program on Parenting Practices and Student Misconduct in a Low Performing Elementary School in the Northeastern Region of the United States

    ERIC Educational Resources Information Center

    Louissaint, Guirlene

    2013-01-01

    The purpose of this study was to determine the effects of a parent-training program on parenting practices and children's misconduct in a predominately low performing school in the Northeastern region of the United States. The study included 26 parents of children in kindergarten through third grade. The participants were predominately African…

  1. Backarc mafic-ultramafic magmatism in Northeastern Vietnam and its regional tectonic significance

    NASA Astrophysics Data System (ADS)

    Thanh, Ngo Xuan; Hai, Tran Thanh; Hoang, Nguyen; Lan, Vu Quang; Kwon, Sanghoon; Itaya, Tetsumaru; Santosh, M.

    2014-08-01

    The geology of Northern Vietnam offers critical clues on the convergence history between the South China and Indochina blocks. We constrain the tectonic evolution of the South China and Indochina blocks using geochemical, mineral chemical and geochronological data collected from mafic-ultramafic rocks exposed in the Cao Bang area, Northeastern Vietnam. These rocks show significant enrichment in large ionic lithophile elements (LILEs) such as Cs, Rb, Ba, Th, U, and Pb and depletion in high field strength elements (HFSEs) such as Nb, Ta, Zr, and Ti showing [Nb/La]N between 0.28-0.41, [La/Yb]N = 3.94-10.00 and Zr/Y = 2.0-4.4. These geochemical features as well as the petrology and mineral chemistry of the Cao Bang mafic-ultramafic magmas are comparable to those of magmatic complexes formed in a back-arc environment. The basalts yield Rb-Sr whole rock ages of 263 ± 15 Ma, that are consistent with the zircon U-Pb and K-Ar ages reported in previous studies from the same area. The spatial and temporal distribution of the arc magmas within the Indochina block and along the southern margin of the South China block suggest that the Permo-Triassic mafic-ultramafic magmas formed during a tectonic event that is different from the subduction and collision event between the Indochina and South China blocks.

  2. Co-occurrence of arsenic and fluoride in groundwater of semi-arid regions in Latin America: genesis, mobility and remediation.

    PubMed

    Alarcón-Herrera, María Teresa; Bundschuh, Jochen; Nath, Bibhash; Nicolli, Hugo B; Gutierrez, Melida; Reyes-Gomez, Victor M; Nuñez, Daniel; Martín-Dominguez, Ignacio R; Sracek, Ondra

    2013-11-15

    Several million people around the world are currently exposed to excessive amounts of arsenic (As) and fluoride (F) in their drinking water. Although the individual toxic effects of As and F have been analyzed, there are few studies addressing their co-occurrences and water treatment options. Several studies conducted in arid and semi-arid regions of Latin America show that the co-occurrences of As and F in drinking water are linked to the volcaniclastic particles in the loess or alluvium, alkaline pH, and limited recharge. The As and F contamination results from water-rock interactions and may be accelerated by geothermal and mining activities, as well as by aquifer over-exploitation. These types of contamination are particularly pronounced in arid and semi-arid regions, where high As concentrations often show a direct relationship with high F concentrations. Enrichment of F is generally related to fluorite dissolution and it is also associated with high Cl, Br, and V concentrations. The methods of As and F removal, such as chemical precipitation followed by filtration and reverse osmosis, are currently being used at different scales and scenarios in Latin America. Although such technologies are available in Latin America, it is still urgent to develop technologies and methods capable of monitoring and removing both of these contaminants simultaneously from drinking water, with a particular focus towards small-scale rural operations.

  3. A Two-source Energy Balance Model for estimating evapotranspiration over an olive orchard in a semi-arid region of Morocco

    NASA Astrophysics Data System (ADS)

    Ezzahar, Jamal; Chehbouni, Abdelghani; Er-Raki, Salah; Aouade, Ghizlane; Khabba, Said; Merlin, Olivier; Boulet, Gilles; Jarlan, Lionel

    2016-04-01

    In arid and semi-arid regions, about 85% of the available water is used for irrigated agriculture, and therefore a sound and efficient irrigation practice is an important step towards achieving sustainable management of water resources in these regions. In this regard, a better understanding of the water balance is essential for exploring water-saving techniques. One of the most important components of the water balance in semi-arid areas is the evapotranspiration (ET). Therefore, a precise estimation evapotranspiration is of crucial importance for agricultural water management. In this work, a two source energy balance model (TSEB) is used to estimate ET over an irrigated olive orchard located near located near to the Marrakech city (Centre of Morocco). In addition to its simplicity, TSEB does not require a large number of input parameters that are not readily available. Evapotranspiration and micrometeorological parameters were continuously measured during the year 2003 in order to evaluate the performance of TSEB estimates. The comparison between daily estimated and measured evapotranspiration yielded a good agreement although the complexity of the study surface with a correlation coefficient of 0.78 and a root mean square of 61.9wm-².

  4. Use of soil-streamwater relationships to assess regional patterns of acidic deposition effects in the northeastern USA

    USGS Publications Warehouse

    Siemion, Jason; Lawrence, Gregory B.; Murdoch, Peter S.

    2013-01-01

    Declines of acidic deposition levels by as much as 50% since 1990 have led to partial recovery of surface waters in the northeastern USA but continued depletion of soil calcium through this same period suggests a disconnection between soil and surface water chemistry. To investigate the role of soil-surface water interactions in recovery from acidification, the first regional survey to directly relate soil chemistry to stream chemistry during high flow was implemented in a 4144-km2 area of the Catskill region of New York, where acidic deposition levels are among the highest in the East.More than 40% of 95 streams sampled in the southern Catskill Mountains were determined to be acidified and had inorganic monomeric aluminum concentrations that exceeded a threshold that is toxic to aquatic biota. More than 80% likely exceeded this threshold during the highest flows, but less than 10% of more than 100 streams sampled were acidified in the northwestern portion of the region. Median Oa horizon soil base saturation ranged from 50% to 80% at 200 sites across the region, but median base saturation in the upper 10 cm of the B horizon was less than 20% across the region and was only 2% in the southern area. Aluminum is likely to be interfering with root uptake of calcium in the mineral horizon in approximately half the sampled watersheds. Stream chemistry was highly variable over the Catskill region and, therefore, did not always reflect the calcium depletion of the B horizon that our sampling suggested was nearly ubiquitous throughout the region. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  5. Fluvial transport and surface enrichment of arsenic in semi-arid mining regions: examples from the Mojave Desert, California.

    PubMed

    Kim, Christopher S; Stack, David H; Rytuba, James J

    2012-07-01

    As a result of extensive gold and silver mining in the Mojave Desert, southern California, mine wastes and tailings containing highly elevated arsenic (As) concentrations remain exposed at a number of former mining sites. Decades of weathering and erosion have contributed to the mobilization of As-enriched tailings, which now contaminate surrounding communities. Fluvial transport plays an intermittent yet important and relatively undocumented role in the migration and dispersal of As-contaminated mine wastes in semi-arid climates. Assessing the contribution of fluvial systems to tailings mobilization is critical in order to assess the distribution and long-term exposure potential of tailings in a mining-impacted environment. Extensive sampling, chemical analysis, and geospatial mapping of dry streambed (wash) sediments, tailings piles, alluvial fans, and rainwater runoff at multiple mine sites have aided the development of a conceptual model to explain the fluvial migration of mine wastes in semi-arid climates. Intense and episodic precipitation events mobilize mine wastes downstream and downslope as a series of discrete pulses, causing dispersion both down and lateral to washes with exponential decay behavior as distance from the source increases. Accordingly a quantitative model of arsenic concentrations in wash sediments, represented as a series of overlapping exponential power-law decay curves, results in the acceptable reproducibility of observed arsenic concentration patterns. Such a model can be transferable to other abandoned mine lands as a predictive tool for monitoring the fate and transport of arsenic and related contaminants in similar settings. Effective remediation of contaminated mine wastes in a semi-arid environment requires addressing concurrent changes in the amounts of potential tailings released through fluvial processes and the transport capacity of a wash.

  6. Surface water characterization of three rivers in the lead/zinc mining region of northeastern Macedonia.

    PubMed

    Ramani, Sheriban; Dragun, Zrinka; Kapetanović, Damir; Kostov, Vasil; Jordanova, Maja; Erk, Marijana; Hajrulai-Musliu, Zehra

    2014-05-01

    Mine waste is recognized as being one of the most serious threats for freshwater ecosystems, and it still represents one of the greatest environmental concerns in Macedonia. The aim of our investigation was to obtain an in-depth understanding of mining influence on freshwater systems from water contamination to effects on aquatic organisms. In this study, we assessed the impact of active lead (Pb)/zinc (Zn) mines Zletovo and Toranica on the water quality of three rivers in northeastern Macedonia (Bregalnica, Zletovska, and Kriva rivers) based on data collected in spring and autumn of 2012. The Bregalnica River, near Shtip, was characterized mainly by weak contamination with arsenic, barium, iron, molybdenum, titanium, uranium, vanadium, nitrate, and phosphate, as well as critical faecal pollution, which alltogether could be connected to agricultural activities; however, an impact of the mines was not observed. Contrary, both the Zletovska and Kriva rivers showed a clear impact of Pb/Zn mines on water quality. In the Zletovska River, increased concentrations of cadmium (Cd), cobalt, cesium, copper, lithium, manganese (Mn), nickel, rubidium, tin, strontium, thallium, Zn, sulphates, and chlorides were found, especially in autumn (e.g., Cd 2.0 μg L(-1); Mn 2.5 mg L(-1); Zn 1.5 mg L(-1)). In the Kriva River, increased Cd (0.270 μg L(-1)) and Pb (1.85 μg L(-1)) concentrations were found only in spring, possibly due to sediment resuspension during greater water discharge. The selected sampling sites on the Bregalnica, Zletovska, and Kriva rivers were confirmed as being appropriate locations for further studies of mining waste's impact on freshwater ecosystems, the first one as a nonimpacted site and the other two as possible areas of increased exposure of aquatic organisms to metals.

  7. Determination of Source Parameters for Earthquakes in the Northeastern United States and Quebec, Canada by Using Regional Broadband Seismograms

    NASA Astrophysics Data System (ADS)

    Du, W.; Kim, W.; Sykes, L. R.

    2001-05-01

    We studied approximately 20 earthquakes which have occurred in the Northeastern United States and Quebec, southern Canada since 1990. These earthquakes have local magnitude (ML) ranging from 3.5 to 5.2 and are well recorded by broadband seismographic stations in the region. Focal depth and moment tensor of these earthquakes are determined by using waveform inversion technique in which the best fit double-couple mechanism is obtained through a grid search over strike, dip and rake angles. Complete synthetics for three-component displacement signals in the period range 1 to 30 seconds are calculated. In most cases, long period Pnl and surface waves are used to constrain the source parameters. Our results indicate that most of the events show the horizontal compression with near horizontal P axis striking NE-SW. However, three events along the lower St. Lawrence River shows the P axes striking ESE-SE (100-130 degrees) with plunge angles of about 20 degrees. Focal depths of these events range from 2 to 28 km. Four events along the Appalachian Mts. have occurred with 2 to 5 km depths -- Jan. 16, 1994 Reading, Pa sequence, Sep. 25, 1998 Pymatuning, Pa event, Jan. 26, 2001 Ashutabula, Oh earthquake and an event in the Charlevoix seismic zone, Canada (Oct. 28, 1997). Two events have occurred at depth greater than 20 km. These are Quebec City earthquake on Nov. 6, 1997 and Christieville, Quebec event on May 4, 1997. We also observed the apparent discrepancy between the moment magnitude (Mw) and local magnitude (ML). Preliminary results show that for the events studied, Mw tends to be about 0.3 magnitude units smaller than the corresponding ML. However, some events show comparable Mw and ML values, for instance, the 1994 Reading, Pa sequence and Oct. 28, 1997 Charlevoix earthquake. These events have occurred at shallow depths and show low stress drops (less than 100 bars). We believe that this magnitude discrepancy reflects the source characteristics of intraplate events in

  8. Global semi-arid climate change over last 60 years

    NASA Astrophysics Data System (ADS)

    Huang, Jianping; Ji, Mingxia; Xie, Yongkun; Wang, Shanshan; He, Yongli; Ran, Jinjiang

    2016-02-01

    This study analyzes areal changes and regional climate variations in global semi-arid regions over 61 years (1948-2008) and investigates the dynamics of global semi-arid climate change. The results reveal that the largest expansion of drylands has occurred in semi-arid regions since the early 1960s. This expansion of semi-arid regions accounts for more than half of the total dryland expansion. The area of semi-arid regions in the most recent 15 years studied (1990-2004) is 7 % larger than that during the first 15 years (1948-1962) of the study period; this expansion totaled 0.4 × 106 and 1.2 × 106 km2 within the American continents and in the Eastern Hemisphere, respectively. Although semi-arid expansion occurred in both regions, the shifting patterns of the expansion are different. Across the American continents, the newly formed semi-arid regions developed from arid regions, in which the climate became wetter. Conversely, in the continental Eastern Hemisphere, semi-arid regions replaced sub-humid/humid regions, in which the climate became drier. The climate change in drying semi-arid regions over East Asia is primarily dominated by a weakened East Asian summer monsoon, while the wetting of semi-arid regions over North America is primarily controlled by enhanced westerlies.

  9. Potential of Carbon Sequestration as Soil Carbonate in Arid and Semi-arid Region of North China: Impacts of Land Use Change

    NASA Astrophysics Data System (ADS)

    Wang, X.; Wang, J.; Li, X.; Guo, Y.

    2015-12-01

    Soil carbonate (SIC) exceeds organic carbon (SOC) greatly in (semi-)arid lands, thus may be important for carbon sequestration. However, field data for studying SIC dynamics and quantifying SIC accumulation have been lacking. This paper consists of two parts. We first present our recent findings of SIC accumulation in the croplands of north China (Wang et al., 2014; 2015). We then report a meta-analysis of field based SIC data from 745 soil profiles in China. Our recent findings were based on two sets of data: >100 soil samples recently collected from the Yanqi Basin of central Xinjiang and ~200 archived soil samples from four long-term experiment (LTE) sites in the north China. Our study showed that intensive cropping in the arid and semi-arid region leaded to a greater increase in SIC than in SOC; organic amendments enhanced SIC accumulation in the cropland of north China. Our meta-analysis shows that despite a large variation of SIC stock (5-42 kg C m-2), SIC storage in agricultural soils is generally higher relative to non-agricultural soils. We provide assessment how land use change may affect SIC storage in north China.

  10. Application of Dempster-Shafer theory, spatial analysis and remote sensing for groundwater potentiality and nitrate pollution analysis in the semi-arid region of Khuzestan, Iran.

    PubMed

    Rahmati, Omid; Melesse, Assefa M

    2016-10-15

    Effective management and sustainable development of groundwater resources of arid and semi-arid environments require monitoring of groundwater quality and quantity. The aim of this paper is to develop a reasonable methodological framework for producing the suitability map for drinking water through the geographic information system, remote sensing and field surveys of the Andimeshk-Dezful, Khozestan province, Iran as a semi-arid region. This study investigated the delineation of groundwater potential zone based on Dempster-Shafer (DS) theory of evidence and evaluate its applicability for groundwater potentiality mapping. The study also analyzed the spatial distribution of groundwater nitrate concentration; and produced the suitability map for drinking water. The study has been carried out with the following steps: i) creation of maps of groundwater conditioning factors; ii) assessment of groundwater occurrence characteristics; iii) creation of groundwater potentiality map (GPM) and model validation; iv) collection and chemical analysis of water samples; v) assessment of groundwater nitrate pollution; and vi) creation of groundwater potentiality and quality map. The performance of the DS was also evaluated using the receiver operating characteristic (ROC) curve method and pumping test data to ensure its generalization ability, which eventually, the GPM showed 87.76% accuracy. The detailed analysis of groundwater potentiality and quality revealed that the 'non acceptable' areas covers an area of about 1479km(2) (60%). The study will provide significant information for groundwater management and exploitation in areas where groundwater is a major source of water and its exploration is critical to support drinking water need.

  11. A mass collection of Triatoma ryckmani (Hemiptera: Reduviidae) from Stenocereus Eichlamii (Cactaceae) in the semiarid region of Guatemala.

    PubMed

    Marroquín, Ricardo; Bor, Silvia; Monroy, M Carlota

    2004-12-01

    A population of 216 specimens of Stenocereus eichlamii (Cactaceae, Subfamily Cereoideae) was surveyed for Triatoma ryckmani (vector of Chagas disease) in a one hectare plot of semiarid habitat in Guatemala. Out of 44 plants that had dead and dry sections, 24 plants had a total of 103 specimens of T. ryckmani. In comparison with other areas of Guatemala, T ryckmani is well established in the semiarid ecosystem (Infestation index 54.5, density = 2.3 and crowding index 4.3). The insects were mainly found (52.4%) in the dead portions of S. eichlamii 2.0 to 3.2 m above the ground (X2 = 26.0, P < 0.00001), followed by dry cactus sections between 3.2 and 5.0 m (35.9%). They were less frequent 0.2 to 2.0 m above the ground. A considerable proportion (75.7%) had no aparent blood in their digestive systems. To determine the presence of flagellates, 43 of the bugs were dissected, but none were found. This is the first report on T. ryckmani population dynamics in this habitat.

  12. Rainfall interception by Mesquite and Huisache in the semi-arid region of Central México

    NASA Astrophysics Data System (ADS)

    Gonzalez-Sosa, E.; Mastachi-Loza, C. A.; Becerril-Piña, R.; Braud, I.; Gutierrez-Lopez, M. A.

    2010-12-01

    In Mexico there are a few Studies in semiarid environments about the role of vegetation in the regulation of the hydrological processes mainly related to interception loss (EI). Studies on this environments would allow us to understand the mechanisms that determine the spatial and temporal distribution of the water balance components. The study was carried out during the raining seasons of 2006, 2007 and 2008 in three semiarid sites located in the south of the Mexican Plateau: El Carmen in Guanajuato State and Amazcala and Cadereyta in the State of Queretaro. The work aim was to quantify and to model the rainfall interception process employing an adequate sampling strategy and an evaluation of the models developed by Rutter et al. (1975) and Gash (1979) in two shrubs species: huisache (Acacia farnesisna) and mesquite (Prosopis laevigata) both, in situ. A total of 18, 20, and 59 precipitation events (where EI was quantified) were measured for each species in Amazcala, Cadereyta and El Carmen respectively, making a total of 194 EI records. It was found that EI represented between 20% and 22% of the total rainfall (PG), Gash’s model reproduced EI with satisfactory efficiency (E>0.6) and wind’s speed and maximum intensity have a local effect on EI.

  13. Comparison Of Multi-Frequency SAR Land Cover Signatures For Multi-Site Semi-Arid Regions Of Africa

    NASA Astrophysics Data System (ADS)

    Spies, Bernard; Lamb, Alistair; Brown, Sarah, Balzter, Heiko; Fisher, Peter

    2013-12-01

    This study shows the analysis and comparison of different SAR backscatter signatures (σ0 distributions) for distinguishable land cover types over two semi-arid test sites in Africa. The two sites that were chosen are located in Tanzania and Chad, where existing multi- frequency data was available from the different synthetic aperture radar (SAR) archives. Images were grouped into wet and dry season for the Tanzania site, whereas only dry season imagery was available for the Chad site. An IsoData unsupervised classification was applied on all three sets of images to classify seven land cover classes. Random samples were taken from each of the classes, resulting in σ0 distributions for the different classes for each site. These SAR land cover signatures are interpreted and discussed, with further steps identified.

  14. Regional meteorological drivers and long term trends of winter-spring nitrate dynamics across watersheds in northeastern North America

    USGS Publications Warehouse

    Crossman, Jill; Eimers, M Catherine; Casson, Nora J.; Burns, Douglas A.; Campbell, John L; Likens, Gene E; Mitchell, Myron J; Nelson, Sarah J.; Shanley, James B.; Watmough, Shaun A.; Webster, Kara L

    2016-01-01

    This study evaluated the contribution of winter rain-on-snow (ROS) events to annual and seasonal nitrate (N-NO3) export and identified the regional meteorological drivers of inter-annual variability in ROS N-NO3 export (ROS-N) at 9 headwater streams located across Ontario, Canada and the northeastern United States. Although on average only 3.3 % of annual precipitation fell as ROS during winter over the study period, these events contributed a significant proportion of annual and winter N-NO3 export at the majority of sites (average of 12 and 42 %, respectively); with the exception of the most northern catchment, where total winter precipitation was exceptionally low (average 77 mm). In years with a greater magnitude of ROS events, the timing of the peak N-NO3 export period (during spring melt) was redistributed to earlier in the year. Variability in ROS frequency and magnitude amongst sites was high and a generalised linear model demonstrated that this spatial variability could be explained by interactive effects between regional and site-specific drivers. Snowpack coverage was particularly important for explaining the site-specific ROS response. Specifically, ROS events were less common when higher temperatures eliminated snow cover despite increasing the proportion of winter rainfall, whereas ROS event frequency was greater at sites where sufficient snow cover remained. This research suggests that catchment response to changes in N deposition is sensitive to climate change; a vulnerability which appears to vary in intensity throughout the seasonally snow-covered temperate region. Furthermore, the sensitivity of stream N-NO3 export to ROS events and potential shifts (earlier) in the timing of N-NO3 export relative to other nutrients affect downstream nutrient stoichiometry and the community composition of phytoplankton and other algae.

  15. Source and delivery of nutrients to receiving waters in the Northeastern and Mid-Atlantic regions of the United States

    USGS Publications Warehouse

    Moore, Richard B.; Johnston, Criag M.; Smith, Richard A.; Milstead, Bryan

    2011-01-01

    This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake.

  16. Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid-Atlantic Regions of the United States

    USGS Publications Warehouse

    Moore, R.B.; Johnston, C.M.; Smith, R.A.; Milstead, B.

    2011-01-01

    This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake. ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  17. Phase equilibrium modeling, fluid inclusions and origin of charnockites in the Datian region of the northeastern Cathaysia Block, South China

    NASA Astrophysics Data System (ADS)

    Yang, Xiao-Qiang; Li, Zi-Long; Yu, Sheng-Qiang

    2016-08-01

    Charnockites in the Datian region of the northeastern Cathaysia Block, South China have an assemblage of garnet, clinopyroxene, orthopyroxene, plagioclase, anti-perthite, K-feldspar, biotite, quartz and ilmenite. Phase equilibrium modeling indicates that the Datian charnockite was formed at T = 845-855 °C and P = 8.2-8.4 kbar with corresponding water activity lower than 0.50. Fluid inclusions in the Datian charnockite are dominated by N2 and CO2 with minor CH4. The fluids homogenized to liquid at -153.0 to -138.8 °C and 18.3-21.6 °C, respectively, showing a low-density nature. The low-density fluids could be attributed to selective leakage of water due to the affinity of water to melt and decompression-dominated retrograde process. Combined with previous studies, a two-stage formation model is proposed to interpret the petrogenesis of the Datian charnockite, viz emplaced at the Paleoproterozoic and underwent the granulite-facies metamorphism during the Phanerozoic tectonic event.

  18. First ediacaran fauna occurrence in northeastern Brazil (jaibaras basin, ?ediacaran-cambrian): preliminary results and regional correlation.

    PubMed

    Barroso, Francisco R G; Viana, Maria Somália S; de Lima Filho, Mario F; Agostinho, Sonia M O

    2014-09-01

    This study reports the first known occurrence of the Ediacaran fauna in northeastern Brazil (at Pacujá Municipality, northwestern state of Ceará) and presents preliminary interpretations of its significance. Regional correlation indicates that the fossils originated in the Jaibaras Basin and that they may represent a new geological system. The depositional environment can be attributed to a fluviomarine system. Nine Ediacaran species can be identified, including members of pandemic groups (e.g., Charniodiscus arboreus Glaessner, 1959; ?Charniodiscus concentricus Ford, 1958; Cyclomedusa davidi Sprigg, 1947; Ediacaria flindersi Sprigg, 1947; and Medusinites asteroides Sprigg, 1949) and endemic groups (e.g., Kimberella quadrata Glaessner & Wade, 1966; Palaeophragmodictya reticulata Gehling & Rigby, 1996; Parvancorina minchami Glaessner, 1958; and Pectinifrons abyssalis Bamforth, Narbonne, Anderson, 2008). Three ichnogenera are also present: Arenicolites Salter, 1857; Palaeophycus Hall, 1987; and Planolites Nicholson, 1873. The relative age of the deposits is between ?Ediacaran and Cambrian, and the fauna resembles the White Sea Assemblage. The bioturbation presents typical unbranched Ediacaran ichnogenera with little depth in the substrate. This previously unknown occurrence of the Ediacaran fauna reinforces the importance of the state of Ceará to Brazilian and global palaeontology.

  19. Antibacterial activity of carbapenems against clinical isolates of respiratory bacterial pathogens in the northeastern region of Japan in 2007.

    PubMed

    Gomi, Kazunori; Fujimura, Shigeru; Fuse, Katsuhiro; Takane, Hidenari; Nakano, Yoshihisa; Kariya, Yasuko; Kikuchi, Toshiaki; Kurokawa, Iku; Tokue, Yutaka; Watanabe, Akira

    2011-04-01

    As the increasing prevalence of resistant strains of respiratory bacterial pathogens has recently been reported, continuous monitoring of the susceptibility of clinical isolates to antibacterial agents is important. We performed a surveillance study focusing on the susceptibility of major respiratory bacterial pathogens in the northeastern region of Japan to carbapenems and control drugs. A total of 168 bacterial strains isolated from patients with respiratory tract infections in 2007 were collected and the minimum inhibitory concentration (MIC) determined. MIC data were subjected to pharmacokinetic/pharmacodynamic analysis with Monte Carlo simulation to calculate the probability of achieving the target of time above MIC with each carbapenem. All Moraxella catarrhalis, Streptococcus pneumoniae, and methicillin-sensitive Staphylococcus aureus isolates were susceptible to carbapenems. Despite the increasing prevalence of β-lactamase-nonproducing ampicillin-resistant strains, all Haemophilus influenzae isolates were susceptible to meropenem. For Pseudomonas aeruginosa, the susceptibility rates for meropenem and biapenem were 76.7%, and the highest probability of achieving pharmacodynamic target (40% of the time above MIC) was obtained with meropenem 0.5 g three times daily as a 4-h infusion (89.4%), followed by meropenem 0.5 g four times daily as a 1-h infusion (88.4%). Carbapenems have retained their position as key drugs for severe respiratory tract infections.

  20. [A comparative study on water use characteristics and eco-adaptability of Hippophae rhamnoides and Caragana korshinskii in semi-arid loess hilly-gully region].

    PubMed

    Xu, Bingcheng; Shan, Lun

    2004-11-01

    This study compared the seasonal dynamics of soil water content, biomass productivity, and leaf photosynthetic physiology and water potential between about ten years old Hippophae rhamnoides and Caragana korshinskii planted on the hilly slope land of semi-arid loess hilly-gully region. The results showed that there existed dry soil layer in the stands. The seasonal compensation depth of soil water in Hippophae rhamnoides stand was deeper and its water use capability was better than those of C. korshinskii. The yearly productivity of Hippophae rhamnoides was about 2.56 times of C. korshinskii. Hippophae rhamnoides leaf had an increased water use efficiency under improved soil water condition. C. korshinskii had higher photosynthetic and transpiration rates, but its leaf WUE was smaller than Hippophae rhamnoides. These two forests all had drought resistance and tolerance characteristics, but Hippophae rhamnoides was more active than C. korshinskii adapting to drought.

  1. Helminths of the Lizard Salvator merianae (Squamata, Teiidae) in the Caatinga, Northeastern Brazil.

    PubMed

    Teixeira, A A M; Brito, S V; Teles, D A; Ribeiro, S C; Araujo-Filho, J A; Lima, V F; Pereira, A M A; Almeida, W O

    2016-08-29

    The lizard Salvator merianae is a widely distributed species in South America, occurring from southern Amazonia to the eastern Andes and northern Patagonia. Studies on the parasitic fauna of this lizard have revealed that it is a host for helminths in various Brazilian biomes. The present work provides new parasitological data on the gastrointestinal nematodes associated with the lizard S. merianae. Sixteen specimens were analyzed from nine different locations in a semi-arid region in northeastern Brazil. Five species of nematodes were identified. Oswaldofilaria petersi was first recorded as a parasite of the S. merianae, thus increasing the knowledge of the fauna of parasites that infect large Neotropical lizards.

  2. Trends and variations of pH and hardness in a typical semi-arid river in a monsoon climate region during 1985-2009.

    PubMed

    Hao, Shaonan; Li, Xuyong; Jiang, Yan; Zhao, Hongtao; Yang, Lei

    2016-09-01

    The rapid growth of urbanization and industrialization, along with dramatic climate change, has strongly influenced hydrochemical characteristics in recent decades in China and thus could cause the variation of pH and general total hardness of a river. To explore such variations and their potential influencing factors in a river of the monsoon climate region, we analyzed a long-term monitoring dataset of pH, SO4 (2-), NOx, general total hardness (GH), Mg(2+), Ca(2+), and Cl(-) in surface water and groundwater in the Luan River basin from 1985 to 2009. The nonparametric Seasonal Kendall trend test was used to test the long-term trends of pH and GH. Relationship between the affecting factors, pH and GH were discussed. Results showed that pH showed a decreasing trend and that GH had an increasing trend in the long-term. Seasonal variation of pH and GH was mainly due to the typical monsoon climate. Results of correlation analysis showed that the unit area usage amounts of chemical fertilizer, NO3 (-), and SO4 (2-) were negatively correlated with pH in groundwater. In addition, mining activity affected GH spatial variation. Acid deposition, drought, and increasing the use of chemical fertilizers would contribute to the acidification trend, and mining activities would affect the spatial variation of GH. Variations of precipitation and runoff in semi-arid monsoon climate areas had significant influences on the pH and GH. Our findings implied that human activities played a critical role in river acidification in the semi-arid monsoon climate region of northern China.

  3. REGIONAL-SCALE FISH ECOLOGY IN NORTHEASTERN USA LAKES USING A PROBABILITY-BASED SURVEY DESIGN

    EPA Science Inventory

    Historically, most fish ecology has been done at local scales. As these data accumulate, the need to set this knowledge into landscape, regional, and historical context grows. There are important broad-scale issues (e.g., non-point source pollution, biodiversity loss, alien spe...

  4. Nuclear Hybrid Energy Systems - Regional Studies. West Texas and Northeastern Arizona

    SciTech Connect

    Garcia, Humberto E.; Chen, Jun; Kim, Jong S.; McKellar, Michael G.; Deason, Wesley R.; Vilim, Richard B.; Bragg-Sitton, Shannon M.; Boardman, Richard D.

    2015-04-01

    The primary objective of this study is to conduct a preliminary dynamic analysis of two realistic hybrid energy systems (HES) including a nuclear reactor as the main baseload heat generator (denoted as nuclear HES or nuclear hybrid energy systems [NHES]) and to assess the local (e.g., HES owners) and system (e.g., the electric grid) benefits attainable by the application of NHES in scenarios with multiple commodity production and high penetration of renewable energy. It is performed for regional cases - not generic examples - based on available resources, existing infrastructure, and markets within the selected regions. This study also briefly addresses the computational capabilities developed to conduct such analyses, reviews technical gaps, and suggests some research paths forward.

  5. Global semi-arid climate change over last 60 years

    NASA Astrophysics Data System (ADS)

    Ji, Mingxia; Huang, Jianping

    2016-04-01

    This study analyzes areal changes and regional climate variations in global semi-arid regions over 61 years (1948-2008) and investigates the dynamics of global semi- arid climate change. The results reveal that the largest expansion of drylands has occurred in semi-arid regions since the early 1960s. This expansion of semi-arid regions accounts for more than half of the total dryland expansion. The area of semi-arid regions in the most recent 15 years studied (1990-2004) is 7 % larger than that during the first 15 years (1948-1962) of the study period; this expansion totaled 0.4×106 and 1.2×106 km2 within the American continents and in the Eastern Hemisphere, respectively. Although semi-arid expansion occurred in both regions, the shifting patterns of the expansion are different. Across the American continents, the newly formed semi-arid regions developed from arid regions, in which the climate became wetter. Conversely, in the continental Eastern Hemisphere, semi-arid regions replaced sub-humid/humid regions, in which the climate became drier. The climate change in drying semi-arid regions over East Asia is primarily dominated by a weakened East Asian summer monsoon, while the wetting of semi-arid regions over North America is primarily controlled by enhanced westerlies.

  6. Evaluation of hydrological balance and its variability in arid and semi-arid regions of Eurasia from ECMWF 15 year reanalysis

    NASA Astrophysics Data System (ADS)

    Yatagai, Akiyo

    2003-10-01

    Hydrometeorological cycles over arid and semi-arid regions in mid-latitude Eurasia (the Silk Road region) were investigated using meteorological reanalysis data for the period 1979-93, available from the European Centre for Medium-range Weather Forecasts (ECMWF).Results show that seasonal changes of moisture balance in Turkey and central Asia, hereafter referred to as the western region, differ from those in the Taklimakan Desert and Loess Plateau, hereafter referred to as the eastern region. Here, we equate evaporation minus precipitation with the divergence field of the vertically integrated water vapour flux. In the western region, precipitation and positive convergence C of moisture primarily occurs during October-March. In contrast, the eastern region receives precipitation and has its positive C occurring during June-August. As a result, the eastern region has nearly simultaneous seasonal peaks in precipitation P and evapotranspiration E, whereas the western region has minimum P and maximum E in summer.The main annual moisture route for the Silk Road region is from the west to east; however, moisture also comes from the north in July. Over Turkey, moisture arrives from the west and south. In central Asia, however, most of the moisture comes from the west, the convergence peaks in March, and moisture from the south and west is also greater during this month. In the Loess Plateau, moisture enters from the west, the north, and the south, and exits to the east. In July, the peak precipitation and convergence season, all moisture flows are greater for the entire region, and a large influx of moisture from the south occurs during the summer season. The moisture from the south, the monsoonal flow, has a large interannual variability. Copyright

  7. SIR-A imagery in geologic studies of the Sierra Madre Oriental, northeastern Mexico. Part 1 (Regional stratigraphy): The use of morphostratigraphic units in remote sensing mapping

    NASA Technical Reports Server (NTRS)

    Longoria, J. F.; Jimenez, O. H.

    1985-01-01

    SIR-A imaging was used in geological studies of sedimentary terrains in the Sierra Madre Oriental, northeastern Mexico. Geological features such as regional strike and dip, bedding, folding and faulting were readily detected on the image. The recognition of morphostructural units in the imagery, coupled with field verification, enabled geological mapping of the region at the scale of 1:250 000. Structural profiling lead to the elaboration of a morphostructural map allowing the recognition of an echelon folds and field trends which were used to postulate the ectonic setting of the region.

  8. Sequestration of Soil Organic Carbon by Long-Term No-Tillage in a Cool Semi-Arid Region

    NASA Astrophysics Data System (ADS)

    Carr, Patrick M.; Brevik, Eric C.; Horsley, Richard D.; Martin, Glenn B.

    2016-04-01

    Management choices are known to influence soil organic carbon (SOC) amounts and distribution in agricultural soils. No-tillage (NT) has been viewed as a management technique that sequesters SOC, but some recent studies have brought this into question. These studies have indicated that NT concentrates SOC in shallow horizons while depleting SOC at depth rather than increasing SOC throughout the entire soil profile, with no statistical difference between total profile SOC when soils are sampled to depths greater than about 20-30 cm. Therefore, this study was conducted to determine if long-term NT management in a cool semiarid environment showed SOC sequestration as compared to clean-tillage (CT) and reduced-tillage (RT) management when soil depths >30 cm were considered. Soil samples were collected from 0-30, 30-60, and 60-90 cm depth intervals in research plots arranged in a randomized complete block design. No-tillage, RT, and CT treatments had been maintained in these plots at Dickinson, ND, USA for ≥19 yr. Data was analyzed using a mixed model where tillage and soil depth were considered fixed and blocks were considered random effects. SOC levels were higher under NT (64 Mg ha-1) than CT and RT (≤55 Mg ha-1) management in the 0-30 cm depth interval. The same trend was detected in the 30-60 cm depth interval under NT compared with RT, but not when NT was compared with CT. SOC levels were higher under NT (29 Mg ha-1) than under RT (23 Mg ha-1) in the 60-90 cm depth interval. Through the upper 90 cm of the soil profile, SOC levels were significantly higher under NT (127 Mg ha-1) than under CT and RT (≤112 Mg ha-1). The results of this research indicate that NT can increase SOC levels in the 0-90 cm soil depth interval in cool semiarid environments when compared to CT and RT.

  9. Physiography and superficial geology of the copper-nickel study region, northeastern Minnesota

    USGS Publications Warehouse

    Olcott, P.G.; Siegel, D.I.

    1978-01-01

    The surficial geology is largely a result of two southwestward advances of the Rainy Lobe of the Laurentian ice sheet. The Toimi Drumlin Field, the oldest glacial deposit, covers much of the southern part of the region. It is bounded on the north by the Vermilion Moraine Complex, an east-west trending series of terminal and recessional moraines that mark the southerly extent of the second advance of the Rainy Lobe. Thin ground moraine and small outwash deposits occur both within and north of the Vermilion Moraine Complex except in the Embarrass and Dunka River basins where outwash deposits up to 200 feet in thickness fill a deep bedrock valley.

  10. Y-chromosome analysis in Egypt suggests a genetic regional continuity in Northeastern Africa.

    PubMed

    Manni, Franz; Leonardi, Pascal; Barakat, Abdelhamid; Rouba, Hassan; Heyer, Evelyne; Klintschar, Michael; McElreavey, Ken; Quintana-Murci, Lluís

    2002-10-01

    The geographic location of Egypt, at the interface between North Africa, the Middle East, and southern Europe, prompted us to investigate the genetic diversity of this population and its relationship with neighboring populations. To assess the extent to which the modern Egyptian population reflects this intermediate geographic position, ten Unique Event Polymorphisms (UEPs), mapping to the nonrecombining portion of the Y chromosome, have been typed in 164 Y chromosomes from three North African populations. The analysis of these binary markers, which define 11 Y-chromosome lineages, were used to determine the haplogroup frequencies in Egyptians, Moroccan Arabs, and Moroccan Berbers and thereby define the Y-chromosome background in these regions. Pairwise comparisons with a set of 15 different populations from neighboring European, North African, and Middle Eastern populations and geographic analysis showed the absence of any significant genetic barrier in the eastern part of the Mediterranean area, suggesting that genetic variation and gene flow in this area follow the "isolation-by-distance" model. These results are in sharp contrast with the observation of a strong north-south genetic barrier in the western Mediterranean basin, defined by the Gibraltar Strait. Thus, the Y-chromosome gene pool in the modern Egyptian population reflects a mixture of European, Middle Eastern, and African characteristics, highlighting the importance of ancient and recent migration waves, followed by gene flow, in the region.

  11. Detecting and quantifying the extent of desertification and its impact in the semi-arid Sub-Saharan Africa: A case study of the Upper East Region, Ghana

    NASA Astrophysics Data System (ADS)

    Owusu, Alex B.

    The semi-arid Sub-Saharan region of Africa is in a state of permanent instability at a variety of spatio-temporal momentum. Efforts at sustaining and managing this fragile but all-important ecosystem and its processes require collecting, storing and analyzing multispatial and temporal data that are accurate and continuously updated in terms of changes (degradation), types and magnitude of change. Remote sensing techniques based on multispectral satellite-acquired data (AVHRR, Landsat TM and ETM+) have demonstrated an immense potential as a means to detect, quantify, monitor and map these changes. However, much of what satellite sensors can detect and capture, especially in the form of vegetation index (NDVI), do not tell the entire story about land degradation. This research used multispectral remote sensing data from three sensors (AVHRR, Landsat TM, and ETM+ and IKONOS) to detect and quantify the spatio-temporal land degradation (desertification) to validate the local observation and perception of desertification. The study also analyzes data on crop production in search of evidence proving or disproving degradation in the semi-arid sahel-sudan savannah transitional vegetation zone of the UER, Ghana. Multispectral satellite-acquired NDVI, from AVHRR, Landsat TM & ETM+, show that vegetation greenness is on the ascendancy, although there are pockets (localized degradation) signs of severe land degradation; field evidence suggests that the increasing NDVI is caused by vegetation succession where locally adapted horsetail grasses have been displaced by environmentally efficient, short-lived, quick maturing and dense grasses due to excessive burning, rapid population growth and inappropriate development policies. Local people's perceptions, supported by crop production data, suggest extensive land degradation. Other evidence includes food insecurity, diseases, rainfall variability and land extensification to marginal lands. Convergence of evidence suggests that

  12. Determination of unit nutrient loads for different land uses in wet periods through modelling and optimization for a semi-arid region

    NASA Astrophysics Data System (ADS)

    Özcan, Zeynep; Kentel, Elçin; Alp, Emre

    2016-09-01

    Diffuse pollution abatement has been a challenge for decision-makers because of the intermittent nature and difficulty of identifying impacts of non-point sources. Depending on the degree of complexity of the system processes and constraints related to time, budget and human resources, variety of tools are used in diffuse pollution management. Decision-makers prefer to use rough estimates that require limited time and budget, in the preliminary assessment of diffuse pollution. The unit pollution load method which is based on the pollution generation rate per unit area and time for a given land use can aid decision-makers in the preliminary assessment of diffuse pollution. In this study, a deterministic distributed watershed model, SWAT is used together with nonlinear optimization models to estimate unit nutrient pollution loads during wet periods for different land use classes for the semi-arid Lake Mogan watershed that is dominated by agricultural activities. Extensive data sets including in-stream water quality and flowrate measurements, meteorological data, land use/land cover (LULC) map developed using remote sensing algorithms, information about agricultural activities, and soil data are used to calibrate and verify the hydraulic and water quality components of SWAT model. Results show that the unit total nitrogen (TN) and total phosphorus (TP) loads (0.46 kg TN/ha/yr and 0.07 kg TP/ha/yr) generated from the watershed during wet periods are very close to the minimum values of the loads specified in the literature and highly depend on the variations in rainfall. Estimated unit nutrient loads both at watershed scale and for different land use classes can be used to assess diffuse pollution control measures for similar regions with semi-arid conditions and heavy agricultural activity.

  13. Physical and chemical degradation of grassland soils in semi-arid regions: A case from Central Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Yaşar Korkanç, Selma; Korkanç, Mustafa

    2016-12-01

    The aim of this study is to determine some hydro-physical and chemical characteristics of soils on the grassland areas under semi-arid conditions in terms of soil degradation processes. Three sampling plots of 20 × 20 m size were selected from the Emen Plain as Locations-I, II and III basing on the area covered with vegetation and visual soil properties; and total 108 soil samples from 2 points and 3 depth levels (0-20 cm, 20-40 cm, 40-60 cm) of each sampling plot. Soils of the research area are in degradation process in terms of some physical and chemical characteristics. It was observed that soil properties (i.e. bulk density, total porosity, organic matter, pH, electrical conductivity and saturated hydraulic conductivity) in Location-II and Location-III changed negatively in comparison to Location-I almost at all depths. In the Location-III grassland, bulk density, pH, electrical conductivity and Na + values are higher than those in Location-I, whereas the organic matter, total porosity and saturated hydraulic conductivity values are low. Grassland area is vulnerable to erosion. High Exchangeable Sodium Percentage (ESP) values in Locations-II and III indicates the sodicity problem in these areas.

  14. Soil temperature investigations using satellite acquired thermal-infrared data in semi-arid regions. Thesis. Final Report; [Utah

    NASA Technical Reports Server (NTRS)

    Day, R. L.; Petersen, G. W.

    1983-01-01

    Thermal-infrared data from the Heat Capacity Mapping Mission satellite were used to map the spatial distribution of diurnal surface temperatures and to estimate mean annual soil temperatures (MAST) and annual surface temperature amplitudes (AMP) in semi-arid east central Utah. Diurnal data with minimal snow and cloud cover were selected for five dates throughout a yearly period and geometrically co-registered. Rubber-sheet stretching was aided by the WARP program which allowed preview of image transformations. Daytime maximum and nighttime minimum temperatures were averaged to generation average daily temperature (ADT) data set for each of the five dates. Five ADT values for each pixel were used to fit a sine curve describing the theoretical annual surface temperature response as defined by a solution of a one-dimensinal heat flow equation. Linearization of the equation produced estimates of MAST and AMP plus associated confidence statistics. MAST values were grouped into classes and displayed on a color video screen. Diurnal surface temperatures and MAST were primarily correlated with elevation.

  15. Sedum-dominated green-roofs in a semi-arid region increase CO2 concentrations during the dry season.

    PubMed

    Agra, Har'el; Klein, Tamir; Vasl, Amiel; Shalom, Hadar; Kadas, Gyongyver; Blaustein, Leon

    2017-04-15

    Green roofs are expected to absorb and store carbon in plants and soils and thereby reduce the high CO2 concentration levels in big cities. Sedum species, which are succulent perennials, are commonly used in extensive green roofs due to their shallow root system and ability to withstand long water deficiencies. Here we examined CO2 fixation and emission rates for Mediterranean Sedum sediforme on green-roof experimental plots. During late winter to early spring, we monitored CO2 concentrations inside transparent tents placed over 1m(2) plots and followed gas exchange at the leaf level using a portable gas-exchange system. We found high rates of CO2 emission at daytime, which is when CO2 concentration in the city is the highest. Both plot- and leaf-scale measurements showed that these CO2 emissions were not fully compensated by the nighttime uptake. We conclude that although carbon sequestration may only be a secondary benefit of green roofs, for improving this ecosystem service, other plant species than Sedum should also be considered for use in green roofs, especially in Mediterranean and other semi-arid climates.

  16. Do invasive riparian Tamarix alter hydrology of riparian areas of arid and semi-arid regions under climate change scenarios?

    NASA Astrophysics Data System (ADS)

    Bhattarai, M. P.; Acharya, K.; Chen, L.

    2012-12-01

    Competitiveness of riparian invasive species, Tamarix, in arid and semi-arid riparian areas of the southwestern United States under climate change scenario (SRES A2) was investigated. Tamarix has been replacing native vegetation along the riparian corridors of these areas for the past several decades and is thought to alter water balance. Changes in depth to groundwater, soil moisture distribution and flood frequency are critical in survival and growth of a facultative phreatophyte such as Tamarix. In this study, a fully coupled 2d surface flow and 3d subsurface flow hydrologic model, HydroGeoSphere, was used to simulate surface-subsurface hydrology of the lower Virgin River basin (4500 sq. km), located in Nevada, Utah and Arizona. The hydrologic model results, depth to groundwater and soil saturation, were then applied to the species distribution model, Maxent, along with other bioclimatic parameters to asses future Tamarix distribution probability. Simulations were made for the climate scenarios of the end of 21st centry conditions. Depth to groundwater is found to be the most important predictor variable to the Maxent model. Future Tamarix distribution range is not uniform across the basin. It is likely to decrease at lower elevations and increase in some higher elevation areas.

  17. Water-quality characteristics of six small, semiarid watersheds in the Green River coal region of Colorado

    USGS Publications Warehouse

    Turk, John T.; Parker, Randolph S.

    1982-01-01

    Analysis of major and trace constituents in streams flowing through six semiarid watersheds indicates that the stream chemistry is characterized by saturation with respect to common carbonate minerals (calcium, magnesium, iron, manganese, and lead). The solubility of the carbonate minerals may be a major control on the absolute and relative concentrations of calcium, magnesium, bicarbonate, iron, manganese, and lead; however, other mechanisms probably control the concentrations of cadmium and zinc. Statistical analyses indicate that the mean concentrations of the major ions in the two climatic areas studied are significantly (P=0.05) different from one another, with larger mean concentrations in the more arid area. Trace-metal concentrations were similar from one area to another and indistinguishable from site to site (P=0.05) for lead, cadmium, and zinc. Linear regressions of major ion concentration to specific conductance are similar in both areas for sodium, bicarbonate, sulfate, and chloride. Results of the study may be useful in providing a first approximation of stream chemistry in other watersheds with the same geologic setting, determining watersheds with similar geochemical controls, and determining future changes in stream chemistry in the watersheds studied. (USGS)

  18. The use of natural tracers as indicators of soil-water movement in a temperate semi-arid region

    NASA Astrophysics Data System (ADS)

    Allison, G. B.; Hughes, M. W.

    1983-01-01

    In a semi-arid area of southern Australia a change in land use from Eucalyptus scrub to cropping with wheat is shown to have caused considerable change in the mechanism of the movement of soil water and the amount of deep drainage. Chloride concentrations of soil water have been used to show the mean annual amount of deep drainage increases from less than 0.1 to ˜ 3 mm yr. -1 following clearing of the native vegetation. The concentration of environmental tritium in soil water beneath the native vegetation is consistent with the hypothesis that some relatively recent water (post 1960) has penetrated to depths of at least 12m along channels occupied by living roots. Where the native vegetation has been cleared, no water which fell as rain since 1960 was found at depths greater than 2.5 m. 18O and deuterium concentrations suggest that some water movement to the roots of the native vegetation is in the vapour phase.

  19. Access to childbirth care by adolescents and young people in the Northeastern region of Brazil

    PubMed Central

    Furtado, Érida Zoé Lustosa; Gomes, Keila Rejane Oliveira; da Gama, Silvana Granado Nogueira

    2016-01-01

    ABSTRACT OBJECTIVE To identify the factors that interfere with the access of adolescents and young people to childbirth care for in the Northeast region of Brazil. METHODS Cross-sectional study with 3,014 adolescents and young people admitted to the selected maternity wards to give birth in the Northeast region of Brazil. The sample design was probabilistic, in two stages: the first corresponded to the health establishments and the second to women who had recently given birth and their babies. The data was collected by means of interviews and consulting the hospital records, from pre-tested electronic form. Descriptive statistics were used for the univariate analysis, Pearson’s Chi-square test for the bivariate analysis and multiple logistic regressions for the multivariate analysis. Sociodemographic variables, obstetrical history, and birth care were analyzed. RESULTS Half of the adolescents and young people interviewed had not been given guidance on the location that they should go to when in labor, and among those who had, 23.5% did not give birth in the indicated health service. Furthermore, one third (33.3%) had to travel in search of assisted birth, and the majority (66.7%) of the postpartum women came to maternity by their own means. In the bivariate analysis, the variables marital status, paid work, health insurance, number of previous pregnancies, parity, city location, and type of health establishment showed a significant association (p < 0.20) with inadequate access to childbirth care. The multivariate analysis showed that married adolescents and young people (p < 0.015), with no health insurance (p < 0.002) and from the countryside (p < 0.001) were more likely to have inadequate access to childbirth care. CONCLUSIONS Adolescents and young women, married, without health insurance, and from the countryside are more likely to have inadequate access to birth care. The articulation between outpatient care and birth care can improve this access and

  20. Current Epidemiological Assessment of Bancroftian Filariasis in Tanga Region, Northeastern Tanzania

    PubMed Central

    Baraka, Vito; Misinzo, Gerald; Makunde, Williams H.

    2016-01-01

    Background. Tanzania started a countrywide lymphatic filariasis elimination programme in 2000 adopting the mass drug administration (MDA) strategy. The drug used for the programme was the combination of ivermectin and albendazole. However, there is limited information on the current epidemiological trend of the infections, where MDA implementation is ongoing. The present study aimed at assessing the current status of Bancroftian filariasis infection rate and morbidity where MDA has been distributed and administered for over eight rounds. Methodology. The study was a cross-sectional descriptive study involving 272 individuals (>18 years) from endemic communities in Tanga region where MDA has been implemented. Clinical, sociodemographic, and circulating filarial antigen (CFA) test was undertaken using immune chromatographic card test according to the manufacturer's instructions. Results. A total of 472 individuals were screened: 307/472 (65.1%) were males while 165/472 (34.9%) were females. The overall prevalence of CFA was 5.51%, that of hydrocoele was 73.2%, and that of lymphoedema was 16.0%. The prevalence of hydrocoele combined with lymphoedema was 5.5%. Conclusion. Our findings demonstrate a considerable reduction in filarial infection. However, there is clear evidence of ongoing transmission despite the 8 rounds of MDA. It is unlikely that the annual MDA would interrupt filarial transmission; therefore, additional strategies are needed to accelerate lymphatic filariasis control and elimination. PMID:28050171

  1. Hydrology and water quality of the copper-nickel study region, northeastern Minnesota

    USGS Publications Warehouse

    Siegel, Donald I.; Ericson, Donald W.

    1980-01-01

    Data were collected on the hydrology of the Copper-Nickel study region to identify the location and nature of groundwater resources, determine the flow characteristics and general quality of the major streams, and determine the potential effects of mining copper and nickel on the hydrologic stream. Groundwater generally occurs in local flow systems within surficial deposits and in fractures in the upper few hundred feet of bedrock. Yields commonly range from 1 to 5 gallons per minute from wells in surficial materials and bedrock, but can be as much as 1,000 gallons per minute from wells in the sand and gravel aquifer underlying the Embarrass River valley. Groundwater generally is calcium-magnesium bicarbonate types. Over a mineralized zone, groundwater has concentrations of copper and nickel greater than 5 micrograms per liter. The average annual runoff from streams in the study area is about 10 inches. About 60% of the annual runoff occurs during snowmelt in spring. Flood peaks are reduced in streams that have surface storage available in on-channel lakes and wetlands. Specific conductance in streams can exceed 250 micromhos per centimeter at 25 Celsius where mine dewatering supplements natural discharge. Estimated groundwater discharge to projected copper-nickel mines ranges from less than 25 to about 2,000 gallons per minute. The introduction of trace metals from future mining activities to the groundwater system can be reduced if tailings basins and stockpiles are located on material which has low permeability, such as till, peat, or bedrock. (USGS)

  2. [Simulation on the restoration effect of soil moisture in alfalfa (Medicago sativa)-grain rotation system in semi-arid and drought-prone regions of Loess Plateau].

    PubMed

    Wang, Xue-Chun; Li, Jun; Fang, Xin-Yu; Sun, Jian; Tahir, Muhammad Naveed

    2011-01-01

    With the combination of field survey and EPIC modeling, this paper simulated the restoration effect of soil moisture in different alfalfa (Medicago sativa)-grain rotation systems in semi-arid and drought-prone regions of Loess Plateau. In perennial alfalfa field and in grain crop field after alfalfa, the correlation coefficients between the simulated and observed values of soil moisture content in 0-10 m layer were larger than 0.9 (P < 0.01), and their relative root mean square errors were between 0.05 and 0.16, with the relative errors less than 10%. The dynamic changes of the simulated soil moisture contents in different soil layers were consistent with those of the observed values. In the study regions, it was difficult for the restoration of soil moisture in the deep soil layers of alfalfa field. During the cultivation of alfalfa, the soil moisture content in the layers at 8-10 m depth should not be less than 5.7%. Considering the sustainable development of agricultural production, the appropriate cultivation duration of alfalfa should be 4-6 years and no more than 8 years. For the restoration of soil moisture after alfalfa cultivation in the study regions, the rotation system potato (Solanum tuberosum) --> potato --> spring wheat (Triticum aestivum) could be adopted, and alfalfa could be cultivated again after 32-33 years.

  3. Joint meteorological and hydrological drought model: a management tool for proactive water resources planning of semi-arid regions

    NASA Astrophysics Data System (ADS)

    Modaresi Rad, Arash; Ahmadi Ardakani, Samira; Ghahremani, Zahra; Ghahreman, Bijan; Khalili, Davar

    2016-04-01

    Conventionally drought analysis has been limited to single drought category. Utilization of models incorporating multiple drought categories, can relax this limitation. A copula-based model is proposed, which uses meteorological and hydrological drought indices to assess drought events for ultimate management of water resources, at small scales, i.e., sub-watersheds. The study area is a sub basin located at Karkheh watershed (western Iran), utilizing 41-year data of 4 raingauge stations and one hydrometric station located upstream and at the outlet respectively. Prior to drought analysis, time series of precipitation and streamflow records are investigated for possible dependency/significant trend. Considering the semi-arid nature of the study area, boxplots are utilized to graphically capture the rainy months, which used to evaluate the degree of correlation between streamflow and precipitation records via nonparametric correlations and bivariate tail dependence. Time scales of 3- and 12-month are considered, which are used to study vulnerability of early vegetation establishment and long-term ecosystem resilience, respectively. Among four common goodness of fit tests, the Cramér-von-Mises is found preferable for defining copula distribution functions through Akaike & Bayesian information criteria and coefficient of determination. Furthermore the uncertainty associated with different copula models is measured using the concept of entropy. A new bivariate drought modeling approach is proposed through copulas. The proposed index, named standardized precipitation-streamflow index (SPSI) is compared with two separate indices of streamflow drought index (SDI) and standardized precipitation index (SPI). According to results, the SPSI could detect onset of droughts dominated by precipitation as is similarly indicated by SPI index. It also captures discordant case of normal period precipitation with dry period streamflow and vice versa. Finally, combination of severity

  4. Evaluation of Satellite Based Estimates of Surface Albedo with Ground and Aircraft Observations in a Semi-Arid Region

    NASA Astrophysics Data System (ADS)

    Kassabova, T. D.; Pinker, R. T.; Keefer, T.; Goodrich, D.; Huete, A.; Privette, J.

    2002-05-01

    Surface albedo is an important climate parameter needed for applications that deal with the disposition of radiant energy in the atmosphere and at the surface. Global or large-scale observations of surface albedo are not available, and therefore, it is being monitored from space born instruments. There are trade-offs in the capabilities of the different observational systems. Most satellite sensors are narrow-band and of low temporal resolution, while at a wide range of spatial resolutions. In this study we attempt to derive the surface albedo from two operational satellites, namely a geostationary (GOES-8), and a polar orbiter (NOAA-14), and compare the results with ground-based measurements, as well as with aircraft surveys. Models of atmospheric radiative transfer provide the tools for simulating the broadband and the narrow-band radiances at the top of the atmosphere, and for performing atmospheric corrections. Derived will be angularly and seasonally-dependant relationships between narrowband reflectance and broadband albedo, and the methodology will be tested at the semi-arid USDA-ARS Walnut Gulch Experimental Watershed in Arizona, which serves as a validation site for many space missions, such as ADEOS-II and MODLAND. Specifically, the angularly dependent MODTRAN 3.7 model is used for the simulations. The simulations are performed for 10 solar zenith angles, 6 zenith and 8 azimuth angles, using 5 climatological profiles for temperature, water vapor and ozone for each season derived form the TIGR profiles modified by the Forecast System Laboratory (FSL) rawiosonde information. In the simulations, a spectral surface reference albedo model for open shrub-land is used for each season. It is planned to expand the simulations to additional satellite sensors, such as the GLI on ADEOS II, to facilitate comparison from this mission with operational sensors.

  5. Characteristics of positive cloud-to-ground lightning in Da Hinggan Ling forest region at relatively high latitude, northeastern China

    NASA Astrophysics Data System (ADS)

    Qie, Xiushu; Wang, Zhichao; Wang, Dongfang; Liu, Mingyuan

    2013-12-01

    2009 and 2010, a multistation network of fast and slow antennas was installed on the edge of a relatively high latitude forest region in Da Hinggan Ling (50.4°N, 124.1°E) of northeastern China. The documented 185 positive cloud-to-ground (CG) flashes containing 196 return strokes were analyzed in the paper. It was found that 71.89% of the positive CG flashes contained continuing current. The average duration of continuing current was short with an arithmetic mean value of 33.29 ms and a geometric mean value of 16.74 ms; only one continuing current lasted longer than 150 ms, probably because of the small size of the storm cell in this relatively high latitude region. The vast majority (94.59%) of positive CG flashes was characterized by a single stroke, and the average number of stroke per flash is 1.06. The average charge transferred by positive stroke and continuing current, based upon the analysis of five flashes with well-documented simultaneous measurements of more than five stations, was +5.2 C from a height of 6.0 km (above ground) and +10.2 C from a height of 6.4 km, respectively. The charge moment for +CG strokes ranged from +13.7 C km to +55.9 C km, while that for continuing current ranged from +29.0 C km to +96.9 C km, respectively. The preliminary breakdown process in positive CG flashes can be classified into three types, namely type S (same), type D (different), and type C (chaotic) according to the disparities in the initial polarity of bipolar pulses from the return stroke, which account for 62.92%, 23.60%, and 13.48%, respectively. According to the electric field waveforms indicative (or not indicative) of intracloud (IC) discharge, positive CG flashes are classified into four types, i.e., ordinary positive CG flash (63.78%), hybrid +CG-IC flash (21.08%), hybrid IC-+CG flash (5.41%), and hybrid IC-+CG-IC flash (9.73%). About 15.14% of the recorded positive CG flashes were byproduct of IC lightning discharge.

  6. Carbon dioxide emissions from estuaries of northern and northeastern Brazil.

    PubMed

    Noriega, Carlos; Araujo, Moacyr

    2014-08-22

    The carbon dioxide flux through the air-water interface of coastal estuarine systems must be quantified to understand the regional balance of carbon and its transport through adjacent coastal regions. We estimated and calculated the emissions of carbon dioxide (FCO₂) and the partial pressure of CO₂ (pCO₂) values in 28 estuarine environments at a variety of spatial scales in the northern and northeastern regions of Brazil. The results showed a mean FCO₂ (water to air) of 55 ± 45 mmol·m(-2)·d(-1). Additionally, a negative correlation between dissolved oxygen saturation and pCO₂ was observed, indicating a control by biological processes and especially by organic matter degradation. This leads to increased dissolved CO₂ concentration in estuarine waters which results in a pCO₂ that reached 8,638 μatm. Our study suggests that northern and northeastern Brazilian estuaries act as sources of atmospheric CO₂. The range of pCO₂ observed were similar to those found in inner estuaries in other places around the world, with the exception of a few semi-arid estuaries (Köppen climate classification - BSh) in which record low levels of pCO₂ have been detected.

  7. Carbon dioxide emissions from estuaries of northern and northeastern Brazil

    PubMed Central

    Noriega, Carlos; Araujo, Moacyr

    2014-01-01

    The carbon dioxide flux through the air–water interface of coastal estuarine systems must be quantified to understand the regional balance of carbon and its transport through adjacent coastal regions. We estimated and calculated the emissions of carbon dioxide (FCO2) and the partial pressure of CO2 (pCO2) values in 28 estuarine environments at a variety of spatial scales in the northern and northeastern regions of Brazil. The results showed a mean FCO2 (water to air) of 55 ± 45 mmol·m−2·d−1. Additionally, a negative correlation between dissolved oxygen saturation and pCO2 was observed, indicating a control by biological processes and especially by organic matter degradation. This leads to increased dissolved CO2 concentration in estuarine waters which results in a pCO2 that reached 8,638 μatm. Our study suggests that northern and northeastern Brazilian estuaries act as sources of atmospheric CO2. The range of pCO2 observed were similar to those found in inner estuaries in other places around the world, with the exception of a few semi-arid estuaries (Köppen climate classification – BSh) in which record low levels of pCO2 have been detected. PMID:25145418

  8. The effect of vegetation and beaver dams on geomorphic recovery rates of incised streams in the semi-arid regions of the Columbia River basin, USA.

    NASA Astrophysics Data System (ADS)

    Pollock, M.; Beechie, T.; Jordan, C.

    2005-05-01

    Channel incision is a common occurrence in semi-arid regions of the Columbia River basin and throughout the world, where a fragile balance between climate, vegetation and geology makes channels susceptible to changes in hillslope erosion, stream discharge and sediment yield. Incision is defined as a rapid downcutting and lowering of the stream bed such that it reduces the frequency and duration of flooding onto the adjacent floodplain. We are studying the feasibility of restoring incised streams throughout the interior Columbia River basin. We hypothesize that under proper land use management, it is possible for them to aggrade such that they reconnect to their former floodplains within relatively short time frames. Theoretical and empirical evidence suggests that over decadal time scales, changes to land management that excludes grazing and allows riparian vegetation to become established can cause significant fill within the incised valleys. Preliminary modeling suggests that factors most affecting the length of time for an incised valley to completely aggrade and reconnect to its pre-incision floodplain are the depth of the incision, sediment production in the watershed, the amount and type of riparian vegetation, and the extent of beaver dam construction. While most natural resource and fisheries managers are aware of widespread incision throughout the Columbia River basin, the extent of incision within the range of the Pacific salmon is largely undocumented. However, we do know many incised streams that historically supported salmon no longer do so, and that habitat conditions are severely degraded in these incised streams. The historical record shows that numerous salmon-bearing streams in the semi-arid region of the interior Columbia River basin once contained narrow and deep, slowly meandering channels lined with cottonwoods, willows and/or sedges, contained numerous beaver dams, contained abundant and easily accessible off-channel habitat on the floodplain

  9. Topological and geometrical analysis of a low-dimensional chaotic model obtained for the dynamics of cereal crops cycles observed from satellite in semi-arid region

    NASA Astrophysics Data System (ADS)

    Mangiarotti, Sylvain

    2014-05-01

    A low-dimensional chaotic model was recently obtained for the dynamics of cereal crops cycles in semi-arid region [1]. This model was obtained from one single time series of vegetation index measured from space. The global modeling approach [2] was used based on powerful algorithms recently developed for this purpose [3]. The resulting model could be validated by comparing its predictability (a data assimilation scheme was used for this purpose) with a statistical prediction approach based on the search of analogous states in the phase space [4]. The cereal crops model exhibits a weakly dissipative chaos (DKY = 2.68) and a toroidal-like structure. At present, quite few cases of such chaos are known and these are exclusively theoretical. The first case was introduced by Lorenz in 1984 to model the global circulation dynamics [5], which attractor's structure is remained poorly understood. Indeed, one very powerful way to characterize low-dimensional chaos is based on the topological analysis of the attractors' flow [6]. Unfortunately, such approach does not apply to weakly dissipative chaos. In this work, a color tracer method is introduced and used to perform a complete topological analysis of both the Lorenz-84 system and the cereal crops model. The usual stretching and squeezing mechanisms are easily detected in the attractors' structure. A stretching taking place in the globally contracting direction of the flow is also found in both attractors. Such stretching is unexpected and was not reported previously. The analysis also confirms the toroidal type of chaos and allows producing both the skeleton and algebraic descriptions of the two attractors. Their comparison shows that the cereal crops attractor is a new attractor. References [1] Mangiarotti S., Drapreau L., Letellier C., 2014. Two chaotic global models for cereal crops cycles observed from satellite in Northern Morocco. revision submitted. [2] Letellier C., Aguirre L.A., Freitas U.S., 2009. Frequently

  10. Rivers through time: historical changes in the riparian vegetation of the semi-arid, winter rainfall region of South Africa in response to climate and land use.

    PubMed

    Hoffman, M Timm; Rohde, Richard Frederick

    2011-01-01

    This paper examines how the riparian vegetation of perennial and ephemeral rivers systems in the semi-arid, winter rainfall region of South Africa has changed over time. Using an environmental history approach we assess the extent of change in plant cover at 32 sites using repeat photographs that cover a time span of 36-113 years. The results indicate that in the majority of sites there has been a significant increase in cover of riparian vegetation in both the channel beds and adjacent floodplain environments. The most important species to have increased in cover across the region is Acacia karroo. We interpret the findings in the context of historical changes in climate and land use practices. Damage to riparian vegetation caused by mega-herbivores probably ceased sometime during the early 19th century as did scouring events related to large floods that occurred at regular intervals from the 15th to early 20th centuries. Extensive cutting of riparian vegetation for charcoal and firewood has also declined over the last 150 years. Changes in the grazing history as well as increased abstraction and dam building along perennial rivers in the region also account for some of the changes observed in riparian vegetation during the second half of the 20th century. Predictions of climate change related to global warming anticipate increased drought events with the subsequent loss of species and habitats in the study area. The evidence presented here suggests that an awareness of the region's historical ecology should be considered more carefully in the modelling and formulation of future climate change predictions as well as in the understanding of climate change impacts over time frames of decades and centuries.

  11. Net CO2 and water exchanges of trees and grasses in a semi-arid region (Gourma, Mali)

    NASA Astrophysics Data System (ADS)

    Le Dantec, Valérie; Kergoat, Laurent; Timouk, Franck; Hiernaux, Pierre; Mougin, Eric

    2010-05-01

    An improved understanding of plant and soil processes is critical to predict land surface-atmosphere water exchanges, especially in semi-arid environments, where knowledge is still severely lacking. Within the frame of the African Monsoon Multidisciplinary Project (AMMA), eddy covariance and sapflow stations have been installed to document the intensity, the temporal variability and the main drivers of net CO2 fluxes, water fluxes and contribution of the trees to these fluxes in a pastoral Sahelian landscape. Indeed, although the importance of vegetation in the West African monsoon system has long been postulated, extremely few data were available sofar to test and develop land surface models. In particular, data documenting seasonal and inter-annual dynamics of vegetation/atmosphere exchanges did not exist at 15° N in West Africa before AMMA. The site is located in the Gourma, Mali. Vegetation in this area is sparse and mainly composed of annual grasses and forbs, and trees. Vegetation is organized according to soil type and lateral water redistribution, with bare soil with scattered trees on shallow soils and rocky outcrops (35% of the area), annual grasses and scattered trees on sandy soils (65% of the area), and more dense canopies of grasses and trees growing in valley bottoms over clay soil. To quantify tree transpiration in the overall evapotranspiration flux, sapflow measurements, associated to soil moisture measurements, have been conducted on the main tree species (Acacia senegal, A. seyal, A. raddiana, Combretum glutinosum, Balanites aegyptiaca) in a grassland site and in an open forest site, where eddy covariance fluxes measured the total flux. Using this dataset, we have studied the effects of plant diversity on carbon and water fluxes at the foot-print scale and seasonal dynamics of fluxes due to plant phenology and variations of soil water content (SWC). Carbon fluxes were documented as well, over two years. NEE was close to 0 during the dry season

  12. Water and Carbon Fluxes in a Semi-Arid Region Floodplain: Multiple Approaches to Constrain Estimates of Seasonal- and Depth Dependent Fluxes at Rifle, Colorado

    NASA Astrophysics Data System (ADS)

    Tokunaga, T. K.; Wan, J.; Dong, W.; Kim, Y.; Williams, K. H.; Conrad, M. E.; Christensen, J. N.; Bill, M.; Faybishenko, B.; Hobson, C.; Dayvault, R.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    The importance of floodplains as links between watersheds and rivers highlights the need to understand water and carbon fluxes within floodplain profiles, from their surface soil, through the vadose zone and underlying groundwater. Here, we present results of field and laboratory measurements conducted to quantify fluxes at a remediated uranium/vanadium mill tailings site on a floodplain at Rifle, Colorado. This semi-arid site has a vegetated, locally derived fill soil that replaced the original milling-contaminated soil to a depth of about 1.5 m. The fill soil overlies about 4.5 m of native sandy and cobbly alluvium containing the shallow aquifer. The aquifer generally drains into the Colorado River and is underlain by low permeability Wasatch Formation shale. Within this system, key issues being investigated include water and carbon fluxes between the vadose zone and aquifer, and CO2 fluxes through the vadose zone soil out to the atmosphere. Magnitudes of these fluxes are typically low, thus challenging to measure, yet increasingly important to quantify given the expansion of arid and semi-arid regions under changing climate. The results of field investigations demonstrated that the annual water table rise and fall are driven by snowmelt runoff into the Colorado River in late spring to early summer. Tensiometer data indicate that net recharge from the deeper part of the vadose zone into groundwater occurs later in summer, after water table decline. The effectiveness of summer evapotranspiration in limiting groundwater recharge is reflected in water potentials decreasing to as low as -3 MPa within the upper 1.5 m of the vadose zone. Examination of the historical precipitation record further indicates that net recharge only occurs in years with above-average precipitation during winter and spring. These short intervals of net recharge also facilitate C transport into groundwater because of higher organic C concentrations in the vadose zone. Fluxes of CO2 measured

  13. Analysis of the vertical structure and size distribution of dust aerosols over the semi-arid region of the Loess Plateau in China

    NASA Astrophysics Data System (ADS)

    Zhou, B.; Zhang, L.; Cao, X.; Li, X.; Huang, J.; Shi, J.; Bi, J.

    2012-02-01

    Using measurements of dual-wavelength polarisation lidar, particle sizer, and nephelometer from the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL), the properties of dust aerosol extinction coefficient, optical depth, depolarisation ratio, colour ratio, size distribution, and concentration over the semi-arid region of the Loess Plateau in north-western China are analysed in a case study of dust storms from 16-18 March 2010. The results show that dust aerosols are distributed mostly within the lower layer (below 3.0 km), with the dust aerosol extinction coefficient ranging from 0.1 to 1.0 km-1. The average optical depth and depolarisation ratio are near 0.6 and 0.3, respectively, while the colour ratio ranges from 0.8 to 1.0. The mass size distribution of dust aerosols has two peaks at 0.7 μm and 5.0 μm, respectively, while the number size distribution of dust aerosols is log-normal with a maximum near 0.8 μm. Particles in the fine mode (r ≤ 2.5 μm) are predominant in the dust storm. Their number concentration decreases while those of particles in the moderate (2.5 μm < r ≤ 10.0 μm) and coarse (10.0 μm < r ≤ 20.0 μm) modes increase. Based on Mie theory and the number size distribution of the aerosol, the dust aerosol scattering coefficient and its variation with particle size are calculated and analysed. A fairly close correlation is found with that measured by the nephelometer, for which the correlation coefficients are 0.89 and 0.94, respectively, at 520 and 700 nm. It shows a Gaussian distribution of dust aerosol scattering coefficient against effective diameter, with a fitting coefficient of 0.96 and centre diameter of 5.5 μm. The contribution percentages of aerosol within fine, moderate, and coarse modes to dust aerosol scattering coefficient are 20.95%, 62.93%, and 16.12%, respectively, meaning that PM10 is a dominant factor in the dust aerosol scattering properties.

  14. Integrated Surface and Ground Water modeling of a tank cascaded sub basin using physically based model in a semi-arid region

    NASA Astrophysics Data System (ADS)

    Ilampooranan, I.; Muthiah, K.; Athikesavan, R.

    2013-05-01

    Hydrological Modeling of tank (small reservoirs) cascaded sub-basin of a semi-arid region is a complex process. Physically based approach can simulate the various processes in surface, unsaturated and saturated ground water zones of such sub basin in an integrated manner. The objectives of the study are (i) to characterize the study area to replicate the physical conditions of surface and saturated zones (ii) to carryout overland flow routing of a tank cascaded basin using physically based modular approach (iii) To simulate the ground water levels in the unconfined aquifer (iv) to study the surface and groundwater dynamics on incorporation of tank cascades in the integrated model. An integrated, physically based model MIKE 11 & MIKE SHE was applied to study the hydrological processes of a tank cascaded semi-arid basin in which flow through tanks were modeled using MIKE 11 and coupled with MIKE SHE in-order to best represent the surface water dynamics in a distributed manner. Sindapalli Uppodai sub-basin, Southern Tamilnadu, India is chosen as study area. There are 15 tanks connected in series forming a tank cascade. Other tanks and depressions in the sub basin are also considered for the study and their effectiveness were analysed. DEM was obtained from SRTM data. The maps such as drainage network, land use and soil are prepared. Soil sampling was carried out. The time series data of rainfall and climate parameters are given as input. The characterization of unconfined aquifer formation was done by Geo-Resistivity survey. 71 observation and pumping wells are monitored within and periphery of sub basin which are used for calibration of the model. The flow routing over the land is done by MIKE SHE's Overland Flow Module, using the diffusive wave approximation of the Saint Venant equation. The hydrograph of routed runoff from the tank cascaded catchment was obtained. The spatial and temporal variation of hydraulic head of the saturated ground water zone is simulated

  15. Using remote sensing to create indicators of ecosystem variability for a semi-arid savanna watershed in the Kavango-Zambezi region of Southern Africa

    NASA Astrophysics Data System (ADS)

    Pricope, Narcisa Gabriela

    This dissertation addresses changes in land and resource availability occurring as a result of climate, water variability and changes in fire regimes in a semi-arid savanna region in Southern Africa. The research combines geospatial analyses of climatological and hydrologic data and various remotely-sensed datasets to create measures of ecosystem variability and adaptability to natural and anthropogenic changes in sensitive ecosystems. The study area is the Chobe River Basin (CRB), a watershed shared between Botswana and Namibia situated at the heart of one of the world.s largest transfrontier conservation areas, where different land-use management strategies and economic policies affect both the ecosystem and the livelihoods support system differentially. The southern African savanna is a highly variable environment and people have adapted to its harshness through the generations. However, in light of past and ongoing environmental changes, their ability to adapt may become threatened. By mapping and then analyzing the spatial and temporal variability of two important factors, namely flooding and fires, in conjunction with indices of vegetation health and productivity, the findings of this research can ultimately contribute to enhancing our understanding of local adaptation mechanisms to future environmental change. This is the first reconstruction of the spatial and temporal patterns of inundation for the last 25 years in the CRB, a transboundary basin with an unusual hydrologic regime and an important water resource for both human and wildlife populations. In the context of increasing temperatures, decreasing precipitation trends and increasing frequencies and intensities of El Nino episodes in southern Africa (Boko et al., 2007), I also investigated changes in fire incidences and marked shifts in fire seasonality both within and outside of protected areas of central Kavango Zambezi Transfrontier Conservation Area (KAZA TFCA). These changes are likely to have a

  16. On-farm assessment of tillage impact on the vertical distribution of soil organic carbon and structural soil properties in a semiarid region in Tunisia.

    PubMed

    Jemai, Imene; Ben Aissa, Nadhira; Ben Guirat, Saida; Ben-Hammouda, Moncef; Gallali, Tahar

    2012-12-30

    In semiarid areas, low and erratic rainfall, together with the intensive agricultural use of soils, has depleted soil organic carbon and degraded the soil's chemical, biological and physical fertility. To develop efficient soil-management practices for the rapid restoration of severely degraded soils, no-till, mulch-based cropping systems have been adopted. Thus, a study was conducted on a farm to evaluate the effect of a no-tillage system (NT) versus conventional tillage (CT) on the vertical (0-50 cm) distribution of soil organic carbon (SOC), bulk density (BD), total porosity (TP), structural instability (SI), stable aggregates and infiltration coefficient (Ks) in a clay loam soil under rain-fed conditions in a semiarid region of north-western Tunisia. CT consisting of moldboard plowing to a depth of 20 cm was used for continuous wheat production. NT by direct drilling under residue was used for 3 (NT3) and 7 (NT7) years in wheat/fava bean and wheat/sulla crop rotations, respectively. SOC was more significantly increased (p < 0.05) by NT3 and NT7 than by CT at respective depths of 0-10 and 0-20 cm, but a greater increase in the uppermost 10 cm of soil was observed in the NT7 field. NT3 management decreased BD and consequently increased TP at a depth of 0-10 cm. The same trend was observed for the NT7 treatment at a depth of 0-30 cm. Ks was not affected by the NT3 treatment but was improved at a depth of 0-30 cm by the NT7 treatment. Changes in BD, TP and Ks in the NT7 plot were significant only in the first 10 cm of the soil. Both NT3 and NT7 considerably reduced SI (p < 0.1) and enhanced stable aggregates (p < 0.05) across the soil profile. These differences were most pronounced under NT7 at a depth of 0-10 cm. The stratification ratio (SR) of the selected soil properties, except that of SI, showed significant differences between the CT and NT trials, indicating an improvement in soil quality. NT management in the farming systems of north-western Tunisia was

  17. Interspecific variation in vessel size, growth and drought tolerance of broad-leaved trees in semi-arid regions of Kenya.

    PubMed

    Kondoh, Shoko; Yahata, Hisashi; Nakashizuka, Tohru; Kondoh, Michio

    2006-07-01

    In semi-arid regions, trees often wither during the dry season. Withering is sometimes manifest as die-back, whereby whithering results in shoot death, which progresses downward from the uppermost part of the crown. In this study, we measured the relationships between height growth and diameter at breast height, die-back frequency and severity, vessel size and specific hydraulic conductivity of four evergreen (Senna siamea (Lamk) H.S. Irwin & Barneby, Jacaranda mimosifolia D. Don, Azadirachta indica A.H.L. Juss and Acacia gerrardii Benth.) and one deciduous (Melia volkensii Gürke) plantation tree species in Kenya, which has a conspicuous dry season. Die-back occurred readily in some species, but not in others. Senna siamea showed the highest specific hydraulic conductivity and the highest growth rate among the five species and was quite susceptible to die-back. Among species, height growth and specific hydraulic conductivity were positively correlated with vessel size and negatively correlated with die-back frequency, suggesting a trade-off between growth rate and drought tolerance. This implies that an adaptation to rapid growth under humid conditions leads to low drought tolerance. However, the deciduous tree Melia volkensii showed high specific hydraulic conductivity and growth, with no symptoms of die-back, implying that a mechanism associated with the deciduous habit results in drought avoidance by reducing the requirement for water during the dry season.

  18. Pollen types and levels of total phenolic compounds in propolis produced by Apis mellifera L. (Apidae) in an area of the Semiarid Region of Bahia, Brazil.

    PubMed

    Matos, Vanessa R; Alencar, Severino M; Santos, Francisco A R

    2014-03-01

    Twenty-two propolis samples produced by Apis mellifera L. in an area of the Semiarid region the the State of Bahia (Agreste of Alagoinhas), Brazil, were palynologically analyzed and quantified regarding their levels of total phenolic compounds. These samples were processed using the acetolysis technique with the changes suggested for use with propolis. We found 59 pollen types belonging to 19 families and 36 genera. The family Fabaceae was the most representative in this study with nine pollen types, followed by the family Asteraceae with seven types. The types Mikania and Mimosa pudica occurred in all samples analyzed. The types Mimosa pudica and Eucalyptus had frequency of occurrence above 50% in at least one sample. The highest similarity index (c. 72%) occurred between the samples ER1 and ER2, belonging to the municipality of Entre Rios. Samples from the municipality of Inhambupe displayed the highest (36.78±1.52 mg/g EqAG) and lowest (7.68 ± 2.58 mg/g EqAG) levels of total phenolic compounds. Through the Spearman Correlation Coefficient we noticed that there was a negative linear correlation between the types Mimosa pudica (rs = -0.0419) and Eucalyptus (rs = -0.7090) with the profile of the levels of total phenolic compounds of the samples.

  19. Spatial and temporal analysis of the drought vulnerability and risks over eight decades in a semi-arid region (Tensift basin: Morocco)

    NASA Astrophysics Data System (ADS)

    Fniguire, Fatima; Laftouhi, Nour-Eddine; Saidi, Mohamed Elmehdi; Zamrane, Zineb; El Himer, Hicham; Khalil, Nourddine

    2016-08-01

    In the last few decades, drought has become a chronic phenomenon in Morocco. It began at the end of the 1970s and continued to the late 2000s. In the present study, hydrometeorological data sets, Standardized Precipitation Index method, and non-parametric tests were used to recognize the frequency and the severity of drought events during the period between 1929 and 2010. The Standardized Precipitation Index showed significant inter-annual fluctuation and evolution of rainfall amounts representing wet cycles (i.e., before 1975) followed by a long period of drought between 1975 and 2004. The inter-annual variability of rainfall is accompanied by shifts of stationarity in the rainfall series. The statistical test of Pettitt, Bayesian method of Lee and Heghinian, Buishand procedure, and Hubert test revealed shifts around the mid 70s. After this period, a deficit of rainfall (with a maximum value of -30 %) was registered. The probabilities of monthly Standardized Precipitation Index values were normal to below normal during the last 40 years. In fact, the increase of drought risk may be resulted from the increase of frequency and severity of meteorological drought. The proposed Standardized Precipitation Index method and non-parametric tests yielded reasonable and satisfactory results for Morocco. Therefore, this approach could be successfully applied to other semi-arid, dry, sub-humid, or semi-humid regions worldwide, where rainfall series are showing high seasonality and year-to-year variability.

  20. Identification of spatiotemporal patterns of biophysical droughts in semi-arid region - a case study of the Karkheh river basin in Iran

    NASA Astrophysics Data System (ADS)

    Kamali, B.; Abbaspour, K. C.; Lehmann, A.; Wehrli, B.; Yang, H.

    2015-06-01

    This study aims at identifying historical patterns of meteorological, hydrological, and agricultural (inclusively biophysical) droughts in the Karkheh River Basin (KRB), one of the nine benchmark watersheds of the CGIAR Challenge Program on Water and Food. Standardized precipitation index (SPI), standardized runoff index (SRI), and soil moisture deficit index (SMDI) were used to represent the above three types of droughts, respectively. The three drought indices were compared across temporal and spatial dimensions. Variables required for calculating the indices were obtained from the Soil and Water Assessment Tool (SWAT) constructed for the region. The model was calibrated based on monthly runoff and yearly wheat yield using the Sequential Uncertainty Fitting (SUFI-2) algorithm. Five meteorological drought events were identified in the studied period (1980-2004), of which four corresponded with the hydrological droughts with 1-3 month lag. The meteorological droughts corresponded well with the agricultural droughts during dry months (May-August), while the latter lasted for a longer period of time. Analysis of drought patterns showed that southern parts of the catchment were more prone to agricultural drought, while less influenced by hydrological drought. Our analyses highlighted the necessity for monitoring all three aspects of drought for a more effective watershed management. The analysis on different types of droughts in this study provides a framework for assessing their possible impacts under future climate change in semi-arid areas.

  1. Anthelmintic efficacy of pumpkin seed (Cucurbita pepo Linnaeus, 1753) on ostrich gastrointestinal nematodes in a semiarid region of Paraíba State, Brazil.

    PubMed

    Feitosa, Thais Ferreira; Vilela, Vinícius Longo Ribeiro; Athayde, Ana Célia Rodrigues; Braga, Fábio Ribeiro; Dantas, Elaine Silva; Vieira, Vanessa Diniz; de Melo, Lídio Ricardo Bezerra

    2013-01-01

    The aim of this study was to verify the in vivo effectiveness of pumpkin seed (Curcubita pepo Linnaeus, 1753) in naturally infected ostriches in the Cariri zone, semiarid region of Paraíba State, Brazil. Forty-eight ostriches were used, African Black breed, of 14 to 36 months old, naturally infected by gastrointestinal nematodes. These animals were divided into four groups of 12 ostriches. Group 1 consists of animals treated with 0.5 g/kg live weight (l. w.) of pumpkin seed meal; group 2 received 1 g/kg l. w. of pumpkin seed meal; group 3 was treated with Albendazole 5 %, at the dosage of 1 mL/10 kg l. w.; and Group 4 was the control group and do not received treatment. Groups 1 and 2 received the treatment for three consecutive days, orally, at intervals of 7 days, totaling nine administrations. The Albendazole 5 % was administered one time, at the beginning of the experiment, according to the manufacturer's recommendations. The groups treated with pumpkin seed showed a significant decrease in egg counts per gram of feces (EPG), wherein group 2 (1 g/kg l. w.) was the most effective. The control and drug groups showed no reduction in EPG. The results of the present study demonstrate that the administration of pumpkin seed was effective in controlling gastrointestinal helminths in naturally infected ostriches.

  2. Denitrification potential and its correlation to physico-chemical and biological characteristics of saline wetland soils in semi-arid regions.

    PubMed

    Yu, Huibin; Song, Yonghui; Xi, Beidou; Du, Erdeng; He, Xiaosong; Tu, Xiang

    2012-11-01

    Denitrification is an important pathway of NO(3)(-) removal depending on wetland soil characteristics. Most studies on denitrification have been conducted in the freshwater wetlands and coastal marshes, but little information is available on how soil and environmental factors affect denitrification of saline wetlands in semi-arid regions. We conducted a correlative study on denitrification potential in relation to the physico-chemical and biological characteristics. Composite soil samples of different depths were collected from different halophyte communities along a saline-impact gradient around Wuliangsuhai Lake, i.e. Comm. Salicornia europaea (CSE), Comm. Suaeda glauca (CSG), Comm. Kalidium foliatum (CKF) and Comm. Sophora alopecuroides (CSA). The CSA soil profile showed the fastest denitrification kinetics and tended to yield the largest amount of N(2)O, followed by the CKF, CSG and CSE. The mean of potential denitrification rates was the highest across all depths of the CSA soil profile, followed by the CKF, CSG, and CSE. Principal component analysis indicated that exchangeable sodium percentage was a key factor to denitrification potential, apart from organic carbon, nitrate and denitrifying bacteria. The results could have significant implication in integrated assessment and management of salined wetlands for treating nutrient-rich return water from farmland, industrial wastewater and domestic sewage in the diverted trunk drain used for the lakeshore restoration.

  3. The geospatial relationship of geologic strata, geological fractures, and land use attained by a time-series aridity index in a semiarid region.

    PubMed

    Rodríguez-Moreno, Victor M; Kretzschmar, Thomas G; Padilla-Ramírez, J Saúl

    2015-07-01

    In a vast semiarid region of the Baja California Peninsula, remote sensing and GIS techniques were applied to moderate resolution images of Landsat 5 TM to explore the geospatial correlation among the grid aridity index (AI), shapefiles of geologic strata, land use, and geological fractures. A dataset of randomized sample points in a time-series of one hydrologic year along with vector file GIS delineated geologic fractures-including the area between their left/right parallel buffer lines-was used as mask analysis. MANOVA results were significant (p < 0.05) for geologic strata, land use, and basin. Overall results reveal the effects of soil texture on water retention on deeper soil horizons and the rate of vertical motion of rainwater. Despite the fact that geologic fractures underlie a large number of biotic communities, in both latitude and longitude gradients of the peninsula, no statistical significance was observed among the fractures themselves or the areas between their parallel buffer lines. One pulse rainfall event was documented by the AI grid maps enabling a robust vegetative response in early summer to an abnormal amount of rain provided by tropical storm Julio. AI grids appear to be useful for characterizing an ecosystem's dynamism. New options are suggested for this research strategy by expanding the number of datasets and incorporating geographic exclusion areas.

  4. Identifying and managing risk factors for salt-affected soils: a case study in a semi-arid region in China.

    PubMed

    Zhou, De; Xu, Jianchun; Wang, Li; Lin, Zhulu; Liu, Liming

    2015-07-01

    Soil salinization and desalinization are complex processes caused by natural conditions and human-induced risk factors. Conventional salinity risk identification and management methods have limitations in spatial data analysis and often provide an inadequate description of the problem. The objectives of this study were to identify controllable risk factors, to provide response measures, and to design management strategies for salt-affected soils. We proposed to integrate spatial autoregressive (SAR) model, multi-attribute decision making (MADM), and analytic hierarchy process (AHP) for these purposes. Our proposed method was demonstrated through a case study of managing soil salinization in a semi-arid region in China. The results clearly indicated that the SAR model is superior to the OLS model in terms of risk factor identification. These factors include groundwater salinity, paddy area, corn area, aquaculture (i.e., ponds and lakes) area, distance to drainage ditches and irrigation channels, organic fertilizer input, and cropping index, among which the factors related to human land use activities are dominant risk factors that drive the soil salinization processes. We also showed that ecological irrigation and sustainable land use are acceptable strategies for soil salinity management.

  5. How To Assess The Future Tree-Cover Potential For Reforestation Planning In Semi-Arid Regions? An Attempt Using The Vegetation Model ORCHIDEE

    NASA Astrophysics Data System (ADS)

    Rajaud, A.; De Noblet-Ducoudré, N.

    2015-12-01

    More and more reforestation projects are undertaken at local to continental scales to fight desertification, to address development challenges, and to improve local living conditions in tropical semi-arid regions. These regions are very sensitive to climatic changes and the potential for maintaining tree-covers will be altered in the next decades. Therefore, reforestation planning needs predicting the future "climatic tree-cover potential": the optimum tree-fraction sustainable in future climatic states. Global circulation models projections provide possible future climatologies for the 21st century. These can be used at the global scale to force a land-surface model, which in turn simulates the vegetation development under these conditions. The tree cover leading to an optimum development may then be identified. We propose here to run a state-of-the-art model and to assess the span and the relevance of the answers that can be obtained for reforestation planning. The ORCHIDEE vegetation model is chosen here to allow a multi-criteria evaluation of the optimum cover, as it returns surface climate state variables as well as vegetation functioning and biomass products. It is forced with global climate data (WFDEI and CRU) for the 20th century and models projections (CMIP5 outputs) for the 21st century. At the grid-cell resolution of the forcing climate data, tree-covers ranging from 0 to 100% are successively prescribed. A set of indicators is then derived from the model outputs, meant for modulating reforestation strategies according to the regional priorities (e.g. maximize the biomass production or decrease the surface air temperature). The choice of indicators and the relevance of the final answers provided will be collectively assessed by the climate scientists and reforestation project management experts from the KINOME social enterprise (http://en.kinome.fr). Such feedback will point towards the model most urging needs for improvement.

  6. Assessment of aerosol radiative forcing in the North-Eastern region of India using radiative transfer model and regional climate model

    NASA Astrophysics Data System (ADS)

    Pathak, Binita; Bhuyan, Pradip

    Regional characterization of atmospheric aerosols is essential from the viewpoint of reducing the current uncertainties in the understanding of their climate implications at regional and global scale. The north-eastern part of India owing to its unique topography and geography located at sub Himalayan range and the middle of Indian Subcontinent and South-East Asian region as well as with scattered local hilly regions persevere complex aerosol environment. Collocated measurements of parameters corresponding to aerosol optical and physical properties i.e., spectral aerosol optical depths (AODs) by a 10 channel Multi-Wavelength solar Radiometer (MWR), near surface aerosol mass concentration of composite aerosols by a Quartz Crystal Microbalance Impactor (QCM) and Black Carbon (BC) mass concentration by an Aethalometer have been used in the Optical Properties of Aerosols and Clouds (OPAC) model to estimate the optical properties of composite aerosols over Dibrugarh (27.3ºN, 94.6ºE, 111 m amsl) for the short wavelength range. The OPAC outputs are then used as inputs to the Rdiative Transfer model ‘Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART)’, developed by the University of California, Santa Barbara, to derive the shortwave aerosol radiative properties. The aerosol optical depth shows maximum value in pre-monsoon season and minimum in post-monsoon season. Columnar aerosols are bimodal in nature with dominant contribution from fine mode aerosols. Unlike columnar aerosols surface aerosol concentration including black carbon shows maximum value in winter and minimum in monsoon season. The aerosol radiative forcing (ARF) estimated for the period pre-monsoon 2008-winter 2013 shows maximum value in the pre-monsoon season at the surface as well as in the atmosphere corresponding to highest columnar aerosol loading. The surface forcing varies between -37 Wm-2 in Pre-monsoon 2009 and 2011 to -13 Wm-2 in Post-monsoon 2008 while forcing in the Atmosphere

  7. A combined deficit index for regional agricultural drought assessment over semi-arid tract of India using geostationary meteorological satellite data

    NASA Astrophysics Data System (ADS)

    Vyas, Swapnil S.; Bhattacharya, Bimal K.; Nigam, Rahul; Guhathakurta, Pulak; Ghosh, Kripan; Chattopadhyay, N.; Gairola, R. M.

    2015-07-01

    The untimely onset and uneven distribution of south-west monsoon rainfall lead to agricultural drought causing reduction in food-grain production with high vulnerability over semi-arid tract (SAT) of India. A combined deficit index (CDI) has been developed from tri-monthly sum of deficit in antecedent rainfall and deficit in monthly vegetation vigor with a lag period of one month between the two. The formulation of CDI used a core biophysical (e.g., NDVI) and a hydro-meteorological (e.g., rainfall) variables derived using observation from Indian geostationary satellites. The CDI was tested and evaluated in two drought years (2009 and 2012) within a span of five years (2009-2013) over SAT. The index was found to have good correlation (0.49-0.68) with standardized precipitation index (SPI) computed from rain-gauge measurements but showed lower correlation with anomaly in monthly land surface temperature (LST). Significant correlations were found between CDI and reduction in agricultural carbon productivity (0.67-0.83), evapotranspiration (0.64-0.73), agricultural grain yield (0.70-0.85). Inconsistent correlation between CDI and ET reduction was noticed in 2012 in contrast to consistent correlation between CDI and reduction in carbon productivity both in 2009 and 2012. The comparison of CDI-based drought-affected area with those from existing operational approach showed 75% overlapping regions though class-to-class matching was only 40-45%. The results demonstrated that CDI is a potential indicator for assessment of late-season regional agricultural drought based on lag-response between water supply and crop vigor.

  8. Inventories and mobilization of unsaturated zone sulfate, fluoride, and chloride related to land use change in semiarid regions, southwestern United States and Australia

    NASA Astrophysics Data System (ADS)

    Scanlon, Bridget R.; Stonestrom, David A.; Reedy, Robert C.; Leaney, Fred W.; Gates, John; Cresswell, Richard G.

    2009-07-01

    Unsaturated zone salt reservoirs are potentially mobilized by increased groundwater recharge as semiarid lands are cultivated. This study explores the amounts of pore water sulfate and fluoride relative to chloride in unsaturated zone profiles, evaluates their sources, estimates mobilization due to past land use change, and assesses the impacts on groundwater quality. Inventories of water-extractable chloride, sulfate, and fluoride were determined from borehole samples of soils and sediments collected beneath natural ecosystems (N = 4), nonirrigated ("rain-fed") croplands (N = 18), and irrigated croplands (N = 6) in the southwestern United States and in the Murray Basin, Australia. Natural ecosystems contain generally large sulfate inventories (7800-120,000 kg/ha) and lower fluoride inventories (630-3900 kg/ha) relative to chloride inventories (6600-41,000 kg/ha). Order-of-magnitude higher chloride concentrations in precipitation and generally longer accumulation times result in much larger chloride inventories in the Murray Basin than in the southwestern United States. Atmospheric deposition during the current dry interglacial climatic regime accounts for most of the measured sulfate in both U.S. and Australian regions. Fluoride inventories are greater than can be accounted for by atmospheric deposition in most cases, suggesting that fluoride may accumulate across glacial/interglacial climatic cycles. Chemical modeling indicates that fluorite controls fluoride mobility and suggests that water-extractable fluoride may include some fluoride from mineral dissolution. Increased groundwater drainage/recharge following land use change readily mobilized chloride. Sulfate displacement fronts matched or lagged chloride fronts by up to 4 m. In contrast, fluoride mobilization was minimal in all regions. Understanding linkages between salt inventories, increased recharge, and groundwater quality is important for quantifying impacts of anthropogenic activities on groundwater

  9. Inventories and mobilization of unsaturated zone sulfate, fluoride, and chloride related to land use change in semiarid regions, southwestern United States and Australia

    USGS Publications Warehouse

    Scanlon, B.R.; Stonestrom, D.A.; Reedy, R.C.; Leaney, F.W.; Gates, J.; Cresswell, R.G.

    2009-01-01

    Unsaturated zone salt reservoirs are potentially mobilized by increased groundwater recharge as semiarid lands are cultivated. This study explores the amounts of pore water sulfate and fluoride relative to chloride in unsaturated zone profiles, evaluates their sources, estimates mobilization due to past land use change, and assesses the impacts on groundwater quality. Inventories of water-extractable chloride, sulfate, and fluoride were determined from borehole samples of soils and sediments collected beneath natural ecosystems (N = 4), nonirrigated ("rain-fed") croplands (N = 18), and irrigated croplands (N = 6) in the southwestern United States and in the Murray Basin, Australia. Natural ecosystems contain generally large sulfate inventories (7800-120,000 kg/ha) and lower fluoride inventories (630-3900 kg/ha) relative to chloride inventories (6600-41,000 kg/ha). Order-of-magnitude higher chloride concentrations in precipitation and generally longer accumulation times result in much larger chloride inventories in the Murray Basin than in the southwestern United States. Atmospheric deposition during the current dry interglacial climatic regime accounts for most of the measured sulfate in both U.S. and Australian regions. Fluoride inventories are greater than can be accounted for by atmospheric deposition in most cases, suggesting that fluoride may accumulate across glacial/ interglacial climatic cycles. Chemical modeling indicates that fluorite controls fluoride mobility and suggests that water-extractable fluoride may include some fluoride from mineral dissolution. Increased groundwater drainage/recharge following land use change readily mobilized chloride. Sulfate displacement fronts matched or lagged chloride fronts by up to 4 m. In contrast, fluoride mobilization was minimal in all regions. Understanding linkages between salt inventories, increased recharge, and groundwater quality is important for quantifying impacts of anthropogenic activities on groundwater

  10. Draft Genome Sequence of Haloferax sp. Strain ATB1, Isolated from a Semi-Arid Region in the Brazilian Caatinga.

    PubMed

    Castro, Wendel de Oliveira; Torres-Ballesteros, Adriana Maria; Nakayama, Cristina Rossi; Melo, Itamar Soares; Pellizari, Vivian Helena; Silva, Artur; Ramos, Rommel Thiago Jucá

    2014-08-14

    Organisms in the Haloferax genus are extreme halophiles that grow in environments with pH values between 4 and 12, and temperatures between 0°C and 60°C. In the present study, a draft of the first Haloferax sp. strain ATB1 genome isolated from the region of Cariri (in Paraíba State, Brazil) is presented.

  11. A basin-scale approach for assessing water resources in a semiarid environment: San Diego region, California and Mexico

    USGS Publications Warehouse

    Flint, L.E.; Flint, A.L.; Stolp, B.J.; Danskin, W.R.

    2012-01-01

    Many basins throughout the world have sparse hydrologic and geologic data, but have increasing demands for water and a commensurate need for integrated understanding of surface and groundwater resources. This paper demonstrates a methodology for using a distributed parameter water-balance model, gaged surface-water flow, and a reconnaissance-level groundwater flow model to develop a first-order water balance. Flow amounts are rounded to the nearest 5 million cubic meters per year. The San Diego River basin is 1 of 5 major drainage basins that drain to the San Diego coastal plain, the source of public water supply for the San Diego area. The distributed parameter water-balance model (Basin Characterization Model) was run at a monthly timestep for 1940–2009 to determine a median annual total water inflow of 120 million cubic meters per year for the San Diego region. The model was also run specifically for the San Diego River basin for 1982–2009 to provide constraints to model calibration and to evaluate the proportion of inflow that becomes groundwater discharge, resulting in a median annual total water inflow of 50 million cubic meters per year. On the basis of flow records for the San Diego River at Fashion Valley (US Geological Survey gaging station 11023000), when corrected for upper basin reservoir storage and imported water, the total is 30 million cubic meters per year. The difference between these two flow quantities defines the annual groundwater outflow from the San Diego River basin at 20 million cubic meters per year. These three flow components constitute a first-order water budget estimate for the San Diego River basin. The ratio of surface-water outflow and groundwater outflow to total water inflow are 0.6 and 0.4, respectively. Using total water inflow determined using the Basin Characterization Model for the entire San Diego region and the 0.4 partitioning factor, groundwater outflow from the San Diego region, through the coastal plain aquifer to

  12. The status of selected minerals in soil, forage and beef cattle tissues in a semi-arid region of Zimbabwe.

    PubMed

    Ndebele, N; Mtimuni, J P; Mpofu, I D T; Makuza, S; Mumba, P

    2005-07-01

    Five districts in the Matabeleland region, an arid western area of Zimbabwe, were investigated for the status of Ca, P, Na, Cu and Zn in soil, forage and cattle during the wet and dry seasons over a period of one year. The cattle came from the natural grazing lands and were not supplemented at the time of sampling. Some deficiencies in soil Zn and P were found in the districts of Lupane and Bulilimamangwe, respectively. Dry season soil Ca, Cu and P concentrations were significantly higher (p < 0.05) than rainy season values owing to leaching in all five districts. Most forage samples had mineral concentrations below the critical levels known to be adequate for animal requirements. Forage levels of Ca, Na. Cu and Zn significantly increased (p < 0.05) with advancing maturity, while P significantly decreased (p < 0.05) in almost all the districts. Marked deficiencies of minerals were found in cattle tissues and these levels followed the seasonal trend seen in the forage. These results indicate that cattle in Matebeleland are deficient in P, Ca, Cu and Zn and that grazing areas in the region cannot provide adequate levels of the five minerals studied.

  13. Rock outcrops reduce temperature-induced stress for tropical conifer by decoupling regional climate in the semiarid environment

    NASA Astrophysics Data System (ADS)

    Locosselli, Giuliano Maselli; Cardim, Ricardo Henrique; Ceccantini, Gregório

    2016-05-01

    We aimed to understand the effect of rock outcrops on the growth of Podocarpus lambertii within a microrefuge. Our hypothesis holds that the growth and survival of this species depend on the regional climate decoupling provided by rock outcrops. To test this hypothesis, we characterized the microclimate of (1) surrounding vegetation, (2) rock outcrop corridors, and (3) adjacencies. We assessed population structure by collecting data of specimen stem diameter and height. We also assessed differences between vegetation associated or not with outcrops using satellite imaging. For dendrochronological analyses, we sampled 42 individuals. Tree rings of 31 individuals were dated, and climate-growth relationships were tested. Rock outcrops produce a favorable microclimate by reducing average temperature by 4.9 °C and increasing average air humidity by 12 %. They also reduce the variability of atmospheric temperature by 42 % and air humidity by 20 % supporting a vegetation with higher leaf area index. Within this vegetation, specimen height was strongly constrained by the outcrop height. Although temperature and precipitation modulate this species growth, temperature-induced stress is the key limiting growth factor for this population of P. lambertii. We conclude that this species growth and survival depend on the presence of rock outcrops. These topography elements decouple regional climate in a favorable way for this species growth. However, these benefits are restricted to the areas sheltered by rock outcrops. Although this microrefuge supported P. lambertii growth so far, it is unclear whether this protection would be sufficient to withstand the stress of future climate changes.

  14. Rock outcrops reduce temperature-induced stress for tropical conifer by decoupling regional climate in the semiarid environment.

    PubMed

    Locosselli, Giuliano Maselli; Cardim, Ricardo Henrique; Ceccantini, Gregório

    2016-05-01

    We aimed to understand the effect of rock outcrops on the growth of Podocarpus lambertii within a microrefuge. Our hypothesis holds that the growth and survival of this species depend on the regional climate decoupling provided by rock outcrops. To test this hypothesis, we characterized the microclimate of (1) surrounding vegetation, (2) rock outcrop corridors, and (3) adjacencies. We assessed population structure by collecting data of specimen stem diameter and height. We also assessed differences between vegetation associated or not with outcrops using satellite imaging. For dendrochronological analyses, we sampled 42 individuals. Tree rings of 31 individuals were dated, and climate-growth relationships were tested. Rock outcrops produce a favorable microclimate by reducing average temperature by 4.9 °C and increasing average air humidity by 12 %. They also reduce the variability of atmospheric temperature by 42 % and air humidity by 20 % supporting a vegetation with higher leaf area index. Within this vegetation, specimen height was strongly constrained by the outcrop height. Although temperature and precipitation modulate this species growth, temperature-induced stress is the key limiting growth factor for this population of P. lambertii. We conclude that this species growth and survival depend on the presence of rock outcrops. These topography elements decouple regional climate in a favorable way for this species growth. However, these benefits are restricted to the areas sheltered by rock outcrops. Although this microrefuge supported P. lambertii growth so far, it is unclear whether this protection would be sufficient to withstand the stress of future climate changes.

  15. Decadal trend of precipitation and temperature patterns and impacts on snow-related variables in a semiarid region, Sierra Nevada, Spain.

    NASA Astrophysics Data System (ADS)

    José Pérez-Palazón, María; Pimentel, Rafael; Herrero, Javier; José Polo, María

    2016-04-01

    In the current context of global change, mountainous areas constitute singular locations in which these changes can be traced. Early detection of significant shifts of snow state variables in semiarid regions can help assess climate variability impacts and future snow dynamics in northern latitudes. The Sierra Nevada mountain range, in southern Spain, is a representative example of snow areas in Mediterranean-climate regions and both monitoring and modelling efforts have been performed to assess this variability and its significant scales. This work presents a decadal trend analysis throughout the 50-yr period 1960-2010 performed on some snow-related variables over Sierra Nevada, in Spain, which is included in the global climate change observatories network around the world. The study area comprises 4583 km2 distributed throughout the five head basins influenced by these mountains, with altitude values ranging from 140 to 3479 m.a.s.l., just 40 km from the Mediterranean coastline. Meteorological variables obtained from 44 weather stations from the National Meteorological Agency were studied and further used as input to the distributed hydrological model WiMMed (Polo et al., 2010), operational at the study area, to obtain selected snow variables. Decadal trends were obtained, together with their statistical significance, over the following variables, averaged over the whole study area: (1) annual precipitation; (2) annual snowfall; annual (3) mean, (4) maximum and (5) minimum daily temperature; annual (6) mean and (7) maximum daily fraction of snow covered areas; (8) annual number of days with snow cover; (9) mean and (10) maximum daily snow water equivalent; (11) annual number of extreme precipitation events; and (12) mean intensity of the annual extreme precipitation events. These variables were also studied over each of the five regions associated to each basin in the range. Globally decreasing decadal trends were obtained for all the meteorological variables

  16. Evaluation of the effectiveness of Duddingtonia flagrans and Monacrosporium thaumasium in the biological control of gastrointestinal nematodes in female bovines bred in the semiarid region.

    PubMed

    Silva, Manoel Eduardo da; Braga, Fabio Ribeiro; Borges, Luana Alcântara; Oliveira, Jair Mendes de; Lima, Walter dos Santos; Guimarães, Marcos Pezzi; Araújo, Jackson Victor de

    2014-06-01

    Brazil has a herd of 212 million cattle and 171 million hectares of pastures that produce approximately 96 % of Brazilian beef. The Brazilian production system enables animal infection by endoparasites, which are considered one of the main obstacles for the development of this industry and are responsible for considerable economic losses. The control of parasitic diseases is performed via the administration of antiparasitic drugs, but they leave residues of the products in the treated animal, affect non-target organisms and select resistant strains of the parasites. The species D. flagrans and M. thaumasium are promising and sustainable alternatives for controlling gastrointestinal helminths of ruminants and other herbivores. In this study, we evaluated the efficacy of isolates of these species, formulated in a sodium alginate matrix and administered twice a week, to reduce the number of environmental infective larvae of gastrointestinal nematodes that affect prepubescent zebu females. The treated animals presented fewer eggs and a lower number of infective larvae per gram of faeces (p < 0.05). The pastures occupied by treated animals showed a statistically significant reduction (p < 0.05) of the number of L3 and, furthermore, the genera Cooperia sp., Haemonchus sp., and Oesophagostomum sp. were the most prevalent. The average weight of the animals did not differ statistically (p > 0.05) among the treated and control groups. The use of sodium alginate pellets as vehicle for delivery of the fungus mycelia D. flagrans (isolate AC001) and M. thaumasium (isolate NF34A) proved effective in controlling trichostrongylids in prepubescent cows bred in the semi-arid region, with an effective reduction in the number of infective larvae in the pastures.

  17. Development and Application of an Integrated Model for Representing Hydrologic Processes and Irrigation at Residential Scale in Semiarid and Mediterranean Regions

    NASA Astrophysics Data System (ADS)

    Herrera, J. B.; Gironas, J. A.; Bonilla, C. A.; Vera, S.; Reyes, F. R.

    2015-12-01

    Urbanization alters physical and biological processes that take place in natural environments. New impervious areas change the hydrological processes, reducing infiltration and evapotranspiration and increasing direct runoff volumes and flow discharges. To reduce these effects at local scale, sustainable urban drainage systems, low impact development and best management practices have been developed and implemented. These technologies, which typically consider some type of green infrastructure (GI), simulate natural processes of capture, retention and infiltration to control flow discharges from frequent events and preserve the hydrological cycle. Applying these techniques in semiarid regions requires accounting for aspects related to the maintenance of green areas, such as the irrigation needs and the selection of the vegetation. This study develops the Integrated Hydrological Model at Residential Scale, IHMORS, which is a continuous model that simulates the most relevant hydrological processes together with irrigation processes of green areas. In the model contributing areas and drainage control practices are modeled by combining and connecting differents subareas subjected to surface processes (i.e. interception, evapotranspiration, infiltration and surface runoff) and sub-surface processes (percolation, redistribution and subsurface runoff). The model simulates these processes and accounts for the dynamics of the water content in different soil layers. The different components of the model were first tested using laboratory and numerical experiments, and then an application to a case study was carried out. In this application we assess the long-term performance in terms of runoff control and irrigation needs of green gardens with different vegetation, under different climate and irrigation practices. The model identifies significant differences in the performance of the alternatives and provides a good insight for the maintenance needs of GI for runoff control.

  18. Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China.

    PubMed

    Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

    2014-01-01

    Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities.

  19. Combining Hydrology and Mosquito Population Models to Identify the Drivers of Rift Valley Fever Emergence in Semi-Arid Regions of West Africa

    PubMed Central

    Soti, Valérie; Tran, Annelise; Degenne, Pascal; Chevalier, Véronique; Lo Seen, Danny; Thiongane, Yaya; Diallo, Mawlouth; Guégan, Jean-François; Fontenille, Didier

    2012-01-01

    Background Rift Valley fever (RVF) is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV) is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. Methodology/Principal Findings A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes) involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961–2003). We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. Conclusion/Significance Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends the

  20. Alpine vegetation phenology dynamic over 16years and its covariation with climate in a semi-arid region of China.

    PubMed

    Zhou, Jihua; Cai, Wentao; Qin, Yue; Lai, Liming; Guan, Tianyu; Zhang, Xiaolong; Jiang, Lianhe; Du, Hui; Yang, Dawen; Cong, Zhentao; Zheng, Yuanrun

    2016-12-01

    Vegetation phenology is a sensitive indicator of ecosystem response to climate change, and plays an important role in the terrestrial biosphere. Improving our understanding of alpine vegetation phenology dynamics and the correlation with climate and grazing is crucial for high mountains in arid areas subject to climatic warming. Using a time series of SPOT Normalized Difference Vegetation Index (NDVI) data from 1998 to 2013, the start of the growing season (SOS), end of the growing season (EOS), growing season length (GSL), and maximum NDVI (MNDVI) were extracted using a threshold-based method for six vegetation groups in the Heihe River headwaters. Spatial and temporal patterns of SOS, EOS, GSL, MNDVI, and correlations with climatic factors and livestock production were analyzed. The MNDVI increased significantly in 58% of the study region, whereas SOS, EOS, and GSL changed significantly in <5% of the region. The MNDVI in five vegetation groups increased significantly by a range from 0.045 to 0.075. No significant correlation between SOS and EOS was observed in any vegetation group. The SOS and GSL were highly correlated with temperature in May and April-May, whereas MNDVI was correlated with temperature in August and July-August. The EOS of different vegetation groups was correlated with different climatic variables. Maximum and minimum temperature, accumulated temperature, and effective accumulated temperature showed stronger correlations with phenological metrics compared with those of mean temperature, and should receive greater attention in phenology modeling in the future. Meat and milk production were significantly correlated with the MNDVI of scrub, steppe, and meadow. Although the MNDVI increased in recent years, ongoing monitoring for rangeland degradation is recommended.

  1. Data reduction and tying in regional gravity surveys—results from a new gravity base station network and the Bouguer gravity anomaly map for northeastern Mexico

    NASA Astrophysics Data System (ADS)

    Hurtado-Cardador, Manuel; Urrutia-Fucugauchi, Jaime

    2006-12-01

    Since 1947 Petroleos Mexicanos (Pemex) has conducted oil exploration projects using potential field methods. Geophysical exploration companies under contracts with Pemex carried out gravity anomaly surveys that were referred to different floating data. Each survey comprises observations of gravity stations along highways, roads and trails at intervals of about 500 m. At present, 265 separate gravimeter surveys that cover 60% of the Mexican territory (mainly in the oil producing regions of Mexico) are available. This gravity database represents the largest, highest spatial resolution information, and consequently has been used in the geophysical data compilations for the Mexico and North America gravity anomaly maps. Regional integration of gravimeter surveys generates gradients and spurious anomalies in the Bouguer anomaly maps at the boundaries of the connected surveys due to the different gravity base stations utilized. The main objective of this study is to refer all gravimeter surveys from Pemex to a single new first-order gravity base station network, in order to eliminate problems of gradients and spurious anomalies. A second objective is to establish a network of permanent gravity base stations (BGP), referred to a single base from the World Gravity System. Four regional loops of BGP covering eight States of Mexico were established to support the tie of local gravity base stations from each of the gravimeter surveys located in the vicinity of these loops. The third objective is to add the gravity constants, measured and calculated, for each of the 265 gravimeter surveys to their corresponding files in the Pemex and Instituto Mexicano del Petroleo database. The gravity base used as the common datum is the station SILAG 9135-49 (Latin American System of Gravity) located in the National Observatory of Tacubaya in Mexico City. We present the results of the installation of a new gravity base network in northeastern Mexico, reference of the 43 gravimeter surveys

  2. An analytical framework for extracting hydrological information from time series of small reservoirs in a semi-arid region

    NASA Astrophysics Data System (ADS)

    Annor, Frank; van de Giesen, Nick; Bogaard, Thom; Eilander, Dirk

    2013-04-01

    small reservoirs in the Upper East Region of Ghana. Reservoirs without obvious large seepage losses (field survey) were selected. To verify this, stable water isotopic samples are collected from groundwater upstream and downstream from the reservoir. By looking at possible enrichment of downstream groundwater, a good estimate of seepage can be made in addition to estimates on evaporation. We estimated the evaporative losses and compared those with field measurements using eddy correlation measurements. Lastly, we determined the cumulative surface runoff curves for the small reservoirs .We will present this analytical framework for extracting hydrological information from time series of small reservoirs and show the first results for our study region of northern Ghana.

  3. Performance of the Santa Ines breed raised on pasture in semiarid tropical regions and factors that explain trait variation.

    PubMed

    de Farias Jucá, Adriana; Faveri, Juliana Cantos; Melo Filho, Geraldo Magalhães; de Lisboa Ribeiro Filho, Antônio; Azevedo, Hymerson Costa; Muniz, Evandro Neves; Pinto, Luís Fernando Batista

    2014-10-01

    This study aimed to evaluate sex, the number of lambs per birth, and the family effects on production traits in the Santa Ines breed of sheep by estimating the least square means and coefficient of variance for those traits. A total of 484 lambs were evaluated for the following traits: weight at birth, at weaning, and at 240 days of age; weight gain during the pre-weaning and post-weaning periods; height, width, and length of different body regions; and rib eye area and fat thickness between the 12th and 13th ribs. We observed coefficients of variation higher than 10 % for several traits. Generally, males were larger than females (P < 0.05), while lambs from single and double births were larger than lambs from triple births (P < 0.05). Family effect was significant (P < 0.05) for most traits and explained the highest percentage of residual variance. The results showed good development of Santa Ines sheep, especially during the pre-weaning period but no in post-weaning. Our study also showed that there is an effect of sex, birth type, and family, which must be included in any statistical model for the estimation of least square means and residual variance in ANOVA.

  4. The role of economic analysis in groundwater management in semi-arid regions: the case of Nigeria

    NASA Astrophysics Data System (ADS)

    Acharya, Gayatri

    The aim of this paper is to use an economic framework to derive decision making rules for river basin management with a focus on groundwater resources. Using an example from northern Nigeria, the paper provides an example of how decision making for sustainable water resources management may be facilitated by comparing net benefits and costs across a river basin. It is argued that economic tools can be used to assess the value of water resources in different uses, identify and analyze management scenarios, and provide decision rules for the sustainable use and management of surface and ground water resources in the region. L'objet de cet article est l'utilisation d'un cadre économique pour établir des règles de prise de décision pour la gestion d'un bassin versant prenant en compte les ressources en eau souterraine. À partir d'un exemple du Nigéria septentrional, cet article explique comment une prise de décision pour la gestion durable de ressources en eau peut être facilitée en comparant les bénéfices nets et les coûts sur tout le bassin versant. Il est montré que les outils économiques peuvent être utilisés pour établir la valeur des ressources en eau dans les différents usages, pour identifier et analyser des scénarios de gestion et pour fournir des règles de décision pour un usage et une gestion durables des ressources en eaux de surface et souterraines dans la région. El objetivo de este artículo es utilizar un enfoque económico para deducir reglas de toma de decisión en la gestión de cuencas, haciendo énfasis en los recursos subterráneos. Por medio de un ejemplo del Norte de Nigeria, se ilustra cómo la toma de decisiones orientadas a la gestión sustentable de los recursos hídricos puede ser facilitada si se compara los beneficios netos y los costes en toda la cuenca. Se argumenta que las herramientas económicas pueden servir para establecer el valor de los recursos hídricos destinados a usos diferentes, para identificar y

  5. Soil moisture and land use are major determinants of soil microbial community composition and biomass at a regional scale in northeastern China

    NASA Astrophysics Data System (ADS)

    Ma, L.; Guo, C.; Lü, X.; Yuan, S.; Wang, R.

    2015-04-01

    Global environmental factors impact soil microbial communities and further affect organic matter decomposition, nutrient cycling and vegetation dynamic. However, little is known about the relative contributions of climate factors, soil properties, vegetation types, land management practices and spatial structure (which serves as a proxy for underlying effects of temperature and precipitation for spatial variation) on soil microbial community composition and biomass at large spatial scales. Here, we compared soil microbial communities using phospholipid fatty acid method across 7 land use types from 23 locations at a regional scale in northeastern China (850 × 50 km). The results showed that soil moisture and land use changes were most closely related to microbial community composition and biomass at the regional scale, while soil total C content and climate effects were weaker but still significant. Factors such as spatial structure, soil texture, nutrient availability and vegetation types were not important. Higher contributions of gram-positive bacteria were found in wetter soils, whereas higher contributions of gram-negative bacteria and fungi were observed in drier soils. The contributions of gram-negative bacteria and fungi were lower in heavily disturbed soils than historically disturbed and undisturbed soils. The lowest microbial biomass appeared in the wettest and driest soils. In conclusion, dominant climate and soil properties were not the most important drivers governing microbial community composition and biomass because of inclusion of irrigated and managed practices, and thus soil moisture and land use appear to be primary determinants of microbial community composition and biomass at the regional scale in northeastern China.

  6. Geoenvironmental and structural studies for developing new water resources in arid and semi-arid regions using remote sensing and GIS

    NASA Astrophysics Data System (ADS)

    Amer, Reda Mohammed

    2011-12-01

    Water crises are rising with increasing world population and decreasing of freshwater resources. This problem is magnified in the arid and semi-arid regions because surface water resources are very limited and highly unreliable and therefore groundwater is the primary source of water supply in these regions. This study presents an integrated approach for the identification of groundwater occurrences using remote sensing, geological, and geophysical data, and establishing sustainable paths to groundwater management. The Central Eastern Desert (CED) of Egypt was selected as a test site for this study because its climate is arid and there is an urgent need to identify potential areas for groundwater accumulations. Field investigations indicated that the CED has three types of aquifers; shallow alluvial (SA), and fracture zone (FZ) aquifers in the valley depressions, and deep aquifers in the sedimentary succession that range in age from Late Cretaceous to Recent in the marginal extensional sub-basins (ESB) along the Red Sea coast. I developed three models: (1) a Geographic Information System (GIS) model for groundwater potential in the SA and FZ shallow aquifers; (2) a kinematic model for the development of the ESB; and (3) a groundwater budget model for the ESB aquifers. The GIS model is based on the analysis of remote sensing data of the Phased Array L-band Synthetic Aperture Radar, the Landsat Enhanced Thematic Mapper Plus, and the Advanced Spaceborne Thermal Emission and Reflection Radiometer digital elevation model. The model was evaluated and proven successful against the existing shallow water wells, and by geophysical surveys using Ground Penetrating Radar and Geoelectric methods. The kinematic model indicated that the ESB were formed in the orthogonal rifting phase in the late Oligocene that is followed by oblique rifting phase during the early Miocene which resulted to the en-echelon pattern of the inland ESB and nucleation of the rift depression into

  7. Zooplankton assemblages in eutrophic reservoirs of the Brazilian semi-arid.

    PubMed

    Eskinazi-Sant'Anna, E M; Menezes, R; Costa, I S; Araújo, M; Panosso, R; Attayde, J L

    2013-02-01

    Species composition, density, and temporal dynamics of zooplankton were studied in six reservoirs in a semi-arid region in tropical northeastern Brazil (Rio Grande do Norte state). All the reservoirs are highly eutrophic, with high contents of total nitrogen (minimum of 1200 µg.L(-1)) and total phosphorus (minimum of 10 µg.L(-1)), and extremely high algal biomass was registered (surpassing 20 µg Chl a.L(-1)). All the reservoirs showed an enduring condition of high turbidity and phytoplankton assemblages dominated by cyanobacteria. Zooplankton also showed quantitative patterns suggestive of eutrophic conditions, expressed by high densities, mainly in Passagem das Traíras and Sabugi reservoirs. A spatial differentiation in the composition of the zooplankton community was registered. Rotifers (especially Keratella tropica, Brachionus havanensis, and Keratella americana) were the dominant forms in the zooplankton community of Itans, Passagem das Traíras, and Sabugi reservoirs, while calanoid copepods (mainly Notodiaptomus cearensis) dominated in the Armando Ribeiro, Gargalheiras, and Parelhas systems. The existence of novel relationships in zooplankton community composition in eutrophic reservoirs in this tropical semi-arid region must be considered in designating zooplankton indicators of eutrophic conditions.

  8. Complete genome sequence of mandarin decline Citrus tristeza virus of the Northeastern Himalayan hill region of India: comparative analyses determine recombinant.

    PubMed

    Biswas, Kajal K; Tarafdar, Avijit; Sharma, Susheel K

    2012-03-01

    The complete genome sequence of a mandarin (Citrus reticulata) decline CTV isolate, Kpg3, of the Darjeeling hills of the Northeastern Himalayan region of India is reported for the first time. The complete Kpg3 genome has 19253 nt, and its nucleotide sequence identity ranged from 79% with the Florida CTV isolate T36 to 94% with the Israel isolate VT, whereas its identity to B165, the other Indian isolate, was 89%. Phylogenetic analysis indicated that the Kpg3 genome is closely related to isolate VT and distantly to T36 and B165. Recombination analysis indicated that Kpg3 is recombinant and originated through multiple recombination events in which parts of the genome were exchanged between divergent CTV sequences.

  9. Regional stratigraphy and distribution of epigenetic stratabound celestine, fluorite, barite and Pb-Zn deposits in the MVT province of northeastern Mexico

    NASA Astrophysics Data System (ADS)

    González-Sánchez, Francisco; Camprubí, Antoni; González-Partida, Eduardo; Puente-Solís, Rafael; Canet, Carles; Centeno-García, Elena; Atudorei, Viorel

    2009-04-01

    Northeastern Mexico hosts numerous epigenetic stratabound carbonate-hosted low-temperature hydrothermal deposits of celestine, fluorite, barite and zinc-lead, which formed by replacement of Mesozoic evaporites or carbonate rocks. Such deposits can be permissively catalogued as Mississippi Valley-type (MVT) deposits. The deposits studied in the state of Coahuila are associated with granitic and metasedimentary basement highs (horsts) marginal or central to the Mesozoic Sabinas Basin. These horsts controlled the stratigraphy of the Mesozoic basins and subsequently influenced the Laramide structural pattern. The Sabinas Basin consists of ~6,000-m-thick Jurassic to Cretaceous siliciclastic, carbonate and evaporitic series. The MVT deposits are mostly in Barremian and in Aptian-Albian to Cenomanian formations and likely formed from basinal brines that were mobilized during the Laramide orogeny, although earlier diagenetic replacement of evaporite layers (barite and celestine deposits) and lining of paleokarstic cavities in reef carbonates (Zn-Pb deposits) is observed. Fluid inclusion microthermometry and isotopic studies suggest ore formation due to mixing of basinal brines and meteoric water. Homogenization temperatures of fluid inclusions range from 45°C to 210°C; salinities range from 0 to 26 wt.% NaCl equiv., and some inclusions contain hydrocarbons or bitumen. Sulfur isotope data suggest that most of the sulfur in barite and celestine is derived from Barremian to Cenomanian evaporites. Regional geology and a compilation of metallogenic features define the new MVT province of northeastern Mexico, which comprises most of the state of Coahuila and portions of the neighboring states of Nuevo León, Durango and, perhaps extends into Zacatecas and southern Texas. This province exhibits a regional metal zonation, with celestine deposits to the south, fluorite deposits to the north and barite and Zn-Pb deposits mostly in the central part.

  10. Surface energy balance estimates at local and regional scales using optical remote sensing from an aircraft platform and atmospheric data collected over semiarid rangelands

    USGS Publications Warehouse

    Kustas, W.P.; Moran, M.S.; Humes, K.S.; Stannard, D.I.; Pinter, P. J.; Hipps, L.E.; Swiatek, E.; Goodrich, D.C.

    1994-01-01

    Remotely sensed data in the visible, near-infrared, and thermal-infrared wave bands were collected from a low-flying aircraft during the Monsoon '90 field experiment. Monsoon '90 was a multidisciplinary experiment conducted in a semiarid watershed. It had as one of its objectives the quantification of hydrometeorological fluxes during the “monsoon” or wet season. The remote sensing observations along with micrometeprological and atmospheric boundary layer (ABL) data were used to compute the surface energy balance over a range of spatial scales. The procedure involved averaging multiple pixels along transects flown over the meteorological and flux (METFLUX) stations. Average values of the spectral reflectance and thermal-infrared temperatures were computed for pixels of order 10−1 to 101 km in length and were used with atmospheric data for evaluating net radiation (Rn), soil heat flux (G), and sensible (H) and latent (LE) heat fluxes at these same length scales. The model employs a single-layer resistance approach for estimating H that requires wind speed and air temperature in the ABL and a remotely sensed surface temperature. The values of Rn and G are estimated from remote sensing information together with near-surface observations of air temperature, relative humidity, and solar radiation. Finally, LE is solved as the residual term in the surface energy balance equation. Model calculations were compared to measurements from the METFLUX network for three days having different environmental conditions. Average percent differences for the three days between model and the METFLUX estimates of the local fluxes were about 5% for Rn, 20% for G and H, and 15% for LE. Larger differences occurred during partly cloudy conditions because of errors in interpreting the remote sensing data and the higher spatial and temporal variation in the energy fluxes. Minor variations in modeled energy fluxes were observed when the pixel size representing the remote sensing inputs

  11. Evaluating persistence and identifying trends and abrupt changes in monthly and annual rainfalls of a semi-arid region in Western India

    NASA Astrophysics Data System (ADS)

    Machiwal, Deepesh; Jha, Madan Kumar

    2016-01-01

    In this study, 43-year (1965-2007) monthly and annual rainfall time series of ten rainfall stations in a semi-arid region of western India are analyzed by adopting three tests for testing normality and by applying autoregressive technique for exploring persistence. Gradual trends are identified by three tests, and their magnitudes are assessed by the Sen's slope estimator. Also, abrupt changes are detected by using four tests and they are further confirmed by two tests. Box-whisker plots revealed that the rainfalls of June and September are right skewed for all the stations. The annual rainfalls of Bhinder, Dhariawad, and Gogunda stations are found considerably right skewed. The normality tests indicated that the rainfall of July does not deviate from the normal distribution at all the stations. However, the annual rainfall is found non-normal at five stations. The monthly rainfalls of June, July, and August have persistence respectively at three (Mavli, Salumber, and Sarada), two (Kherwara and Sarada), and one (Mavli) stations, whereas the annual rainfall has persistence at Girwa and Mavli stations. Significantly increasing trend is detected at Mavli in the rainfall of July and in the annual rainfall (p value > 0.05), while the negative trend in August rainfall at Dhariawad is found significant (p value > 0.10). This study revealed that the presence of serial correlation does not affect the performance of the Mann-Kendall test. Mean values of trend magnitudes for the rainfalls of June, July, August, and September are 0.3, 0.8, -0.4, and 0.4 mm year-1, respectively, and the overall mean value for the annual rainfall is 0.9 mm year-1. It is found that the standard normal homogeneity test and the Pettitt test are biased towards the end of the series to locate a change point. Conversely, the Bayesian test has a tendency to look for a change point in the beginning of time series. Confirmed abrupt changes in the rainfall time series are found in the year 2003 (Bhinder

  12. Evaluation of the SAFRAN-ISBA-RAPID hydrometeorological chain on a mountainous catchment in a semi-arid region. Case of the Rheraya (Marrakech, Morocco)

    NASA Astrophysics Data System (ADS)

    Szczypta, Camille; Gascoin, Simon; Habets, Florence; Saaidi, Amina; Berjamy, Brahim; Marchane, Ahmed; Boulet, Gilles; Hanich, Lahoucine; Jarlan, Lionel

    2015-04-01

    The water content of snow pack is an important resource for many watershed in semi-arid areas where downstream plains are dominated by irrigated agriculture. As part of the ANR Amethyst, this work is to develop, adapt and evaluate a hydro-meteorological forecasting chain for quantifying streamflows at the outlet of a mountainous watershed (Rheraya wadi, Marrakech region, Morocco), a pilot basin instrumented since 2003 as part of SudMed project. Two sets of atmospheric forcing were used: (1) The first was generated by spatializing meteorological data observed on 6 stations (Asni, Aremdt, Tachedert, Oukaimeden, Imskerbour and Neltner) using the semi-physical module Micromet (Liston and Elder, 2006) on the hydrological period September 2003 - August 2012; (2) the second is provided by the SAFRAN re-analysis, implemented by the Metoffice of Morocco (Casablanca, Morocco), during the period August 2004 - July 2008. These two sets were then used as inputs for the ISBA surface model, within the modeling platform SURFEX. Finally, runoff and drainage simulations derived from ISBA were forced into the hydrological model RAPID to predict streamflows. The flows predictions and the snow covered area (SCA) were compared respectively to the observations available for the 2003-2009 period and to the daily MODIS products of SCA. Despite time unsystematic lags and low biases on flow values, the initial results are encouraging due to topographical and hydro-complexity of the studied area. Despite a slight tendency to underestimate the SCA for the "Micromet" run and to over-estimate for the "Safran" run, SCA is well reproduced with a determination coefficient of r²=0.76 and r²=0.79, respectively. Given the complex topography of the basin, a sensitivity analysis to the size of the grid point (from 8 km to 250 m) was conducted. If the different simulated series of SCA are close from a resolution to another, streamflows simulations are, by contrast, highly sensitive to the resolution

  13. Carbon and oxygen isotope study of the active water-carbonate system in a karstic Mediterranean cave: Implications for paleoclimate research in semiarid regions

    SciTech Connect

    Bar-Matthews, M.; Ayalon, A.; Halicz, L.

    1996-01-01

    In a semiarid climatic zone, such as the Eastern Mediterranean region, annual rainfall variations and fractionation processes in the epikarst zone exert a profound influence on the isotopic compositions of waters seeping into a cave. Consequently, the isotopic compositions of speleothems depositing from cave waters may show complex variations that need to be understood if they are to be exploited for paleoclimate studies. This is confirmed by a four-year study of the active carbonate-water system in the Soreq cave (Israel). The {sigma}{sup 18}O (SMOW) values of cave waters range from -6.3 to - 3.5{per_thousand}. The highest {sigma}{sup 18}O values occur at the end of the dry season in waters dripping from stalactites, and reflect evaporation processes in the epikarst zone, whereas the lowest values occur in rapidly dripping (fast-drip) waters at the peak of the rainy seasons. However, even fast-drip waters are about 1.5{per_thousand} heavier than the rainfall above the cave, which is taken to reflect the mixing of fresh with residual evaporated water in the epikarst zone. {sigma}{sup 13}C (PDB) values of dissolved inorganic carbon (DIC) vary from -15.6 to -5.4{per_thousand}, with fast-drip waters having lower {sigma}{sup 13}C values (mostly-15.6 to -12{per_thousand}) and higher DIC concentrations relative to pool and stalactite-drip water. The los {sigma}{sup 13}C values of fast-drip waters and their supersaturation with respect to calcium carbonate indicates that the seepage waters have dissolved both soil-CO{sub 2} derived from overlying C{sub 3}-type vegetation and marine dolomite host rock. The 10{per_thousand} variation in the {sigma}{sup 13}C values associated with contemporaneous speleothems in order to clarify the effects of degassing from those due to differing vegetation types. 55 refs., 10 figs., 1 tab.

  14. Application of a soil moisture diagnostic equation for estimating root-zone soil moisture in arid and semi-arid regions

    NASA Astrophysics Data System (ADS)

    Pan, Feifei; Nieswiadomy, Michael; Qian, Shuan

    2015-05-01

    Knowledge of soil moisture in the root zone is critical for crop growth estimation and irrigation scheduling. In this study, a soil moisture diagnostic equation is applied to estimate soil moisture at depths of 0-100 cm (because the majority of crop roots are in the top 100 cm of soil) at four USDA Soil Climate Analysis Network (SCAN) sites in arid and semi-arid regions: TX2105 in northwest Texas, NM2015 and NM2108 in east New Mexico, and AZ2026 in southeast Arizona. At each site, a dataset of 5-6 years of records of daily soil moisture, daily mean air temperature, precipitation and downward solar radiation is compiled and processed. Both the sinusoidal wave function of day of year (DOY) and a linear function of the potential evapotranspiration (PET) are used to approximate the soil moisture loss coefficient. The first four years of data are used to derive the soil moisture loss function and the empirical parameters in the soil moisture diagnostic equation. The derived loss function and empirical parameters are then applied to estimate soil moisture in the last fifth or sixth year at each site. Root mean square errors (RMSEs) of the estimated volumetric soil moistures in five different soil columns (i.e., 5 cm, 10 cm, 20 or 30 cm, 50 cm, and 100 cm) are less than 3.2 (%V/V), and the accuracy of the estimated soil moistures using the sinusoidal soil moisture loss function is slightly better than the PET-based loss functions. In addition to the three advantages of this soil moisture diagnostic equation, i.e., (1) non-cumulative errors in the estimated soil moisture, (2) no regular recalibration is required to correct the cumulative errors, and (3) no numerical iteration and initial moisture inputs are needed since only precipitation data are required, this study also demonstrates that the soil moisture diagnostic equation not only can be used to estimate surface soil moisture, but also the entire root-zone soil moisture.

  15. Improving estimates of water resources in a semi-arid region by assimilating GRACE data into the PCR-GLOBWB hydrological model

    NASA Astrophysics Data System (ADS)

    Tangdamrongsub, Natthachet; Steele-Dunne, Susan; Gunter, Brian; Ditmar, Pavel; Sutanudjaja, Edwin; Sun, Yu; Xia, Ting; Wang, Zhongjing

    2016-04-01

    An accurate estimate of water resources is critical for proper management of both agriculture and the local ecology, particularly in semi-arid regions where water is scarce. Imperfections in model physics, uncertainties in model land parameters and meteorological data, and the human impact on land changes often limit the accuracy of hydrological models in estimating water storages. To address this problem, this study investigated the assimilation of Terrestrial Water Storage (TWS) estimates derived from the Gravity Recovery And Climate Experiment (GRACE) data using an Ensemble Kalman Filter (EnKF) approach. The region considered was the Hexi Corridor of Northern China. The hydrological model used for the analysis was PCR-GLOBWB, driven by satellite-based forcing data from April 2002 to December 2010. The performance of the GRACE Data Assimilation (DA) scheme was evaluated in terms of its impact on the TWS as well as on the individual hydrological storage estimates. The capability of GRACE DA to adjust the storage level was apparent not only in the TWS but also in the groundwater component, which had annual amplitude, phase, and long-term trend estimates closer to the GRACE observations. This study also assessed the impact of considering correlated errors in GRACE-based estimates. These were derived based on the error propagation approach using the full error variance-covariance matrices provided as a part of the GRACE data product. The assessment was carried out by comparing the EnKF results after excluding (EnKF 1D) and including (EnKF 3D) error correlations with the in situ groundwater data from 5 well sites, and the in situ streamflow data from two river gauges. Both EnKF 1D and 3D improved groundwater and streamflow estimates compared to the results from the PCR-GLOBWB alone (Ensemble Open Loop, EnOL). Although EnKF 3D was inferior to 1D at some groundwater measurement locations, on average, it showed equal or greater improvement in all metrics. For example

  16. Do the seasonal forests in northeastern Brazil represent a single floristic unit?

    PubMed

    Rodal, M J N; Barbosa, M R V; Thomas, W W

    2008-08-01

    Floristic analyses (Principal Component Analysis and Analysis of Group Indicators) at the genus level were employed to characterize and compare seasonal forest formations in northeastern Brazil. The presence--absence of 248 genera of woody plants occurring in 24 floristic surveys was correlated with geomorphology and climatic variables. The analyses were consistent and point to the existence of two floristic groups of seasonal forests in the region, one more closely related to the Atlantic Coastal Forest (mata atlântica) and the other to the xerophytic formations (caatinga) of the region. The driest seasonal forest group experiences more than 8 dry months per year and/or a total annual rainfall of <1000 mm, and is found on the ancient eroded peaks in the semi-arid core and on the western slopes of the Borborema Plateau.

  17. Pasture plants of the Northeastern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperate humid grazing lands are an important component of the landscape of the northeastern Unites States, as well as of the economy of this region, yet unlike their European counterparts, little is known about their basic ecology. During an eight-year survey of 44 farms across the northeastern Un...

  18. Verification of a European corn borer (Lepidoptera: Crambidae) loss equation in the major corn production region of the northeastern United States.

    PubMed

    Dillehay, B L; Calvin, D D; Roth, G W; Hyde, J A; Kuldau, G A; Kratochvil, R J; Russo, J M; Voight, D G

    2005-02-01

    Field studies in Pennsylvania and Maryland were conducted during 2000, 2001, and 2002 to test the applicability of published yield loss relationships developed in central Pennsylvania for European corn borer, Ostrinia nubilalis (Hübner), management in warmer, longer season corn, Zea mays L., grain production regions of the northeastern United States. Both isoline hybrids and non-Bt lead hybrids were compared against Bacillus thuringiensis (Bt) hybrids to measure effects of the pest on yield. The European corn borer economic analysis model was used to make site-specific predictions of loss per European corn borer larva for comparison with measured yield loss per larva. Although the model did not predict loss per larva at a field level, it did predict loss at a regional level. The model predicted an overall percentage of yield loss per larva of 2.69+/-0.12% over the region, which was similar to the measured yield loss per larva of 2.66+/-0.59% for isoline hybrids and 3.08+/-0.51% for lead hybrids. The model, on average, provided a good prediction of percentage of yield loss per larva within the climatic zones of 1100-1700 degree-days (DD) (base threshold 12.5 degrees C). Our results suggest that the yield loss relationship developed in Central Pennsylvania, when matched to the timing of third instar second generation European corn borer stalk tunneling is adequate for major corn grain production zones of the northeast United States.

  19. Potential of remote sensing data for improving water resources management in semi-arid regions: a case study in Burkina Faso

    NASA Astrophysics Data System (ADS)

    Papa, M. N.; Ciervo, F.; Koussoube, y.; Di Martino, G.; Iodice, A.; Natale, A.; Riccio, D.; Ruello, G.; Zinno, I.

    2012-04-01

    In this work we present the rationale and the first results of a Cosmo-SkyMed AO project devoted to use high resolution synthetic aperture radar data for water resource management in semi-arid regions. A case study was developed in Burkina Faso, one of the poorest countries of the world, where almost 80% of the population lives in rural areas depending from agriculture and livestock. It is characterized by the alternation of a rainy (3 months) and a dry (9 months) season, with extreme climate conditions (drought and floods). The project was approved by the Italian Space Agency, that provided Cosmo SkyMed Stripmap (3m resolution) and Spotligth (1m resolution) SAR images. The study area is in the northern part of Burkina Faso around the village of Bidi. A first study is related on the identification of eroded areas, which are indicative of desertification processes. Eroded soils are no more able to absorb and drain water, so that their humidity and, as a consequence, their dielectric constant and conductivity are almost independent by the precipitation. By comparing SAR images acquired during the rainy and the dry seasons, the eroded soils do not change their reflectivity and they can be identified by change detection techniques. In this work we employ innovative fractal change detection techniques, based on the image spectrum evaluation and the comparison of the fractal dimension. As the precipitations occur only during three months, it is crucial to collect water in the rainy season, by the means of artificial basins, in order to irrigate the fields in the dry season. The construction of little artificial basins is usually carried out under the initiative of small associations of farmers. The location, design and management of the basins sometimes is not rational, for the lack of all the information needed for the design. The best location for the construction of a new artificial basin depends on the total volume of surface water that may be collected in one year

  20. Large-scale and Medium-scale Traveling Ionospheric Disturbances Registered during Magnetic Storms over North-Eastern Region of Russian Federation

    NASA Astrophysics Data System (ADS)

    Ivanova, Vera; Kurkin, Vladimir

    2016-07-01

    Earth's ionosphere is dynamical steadily changed medium. On a level with daily and seasonal variations of ionospheric parameters there are irregular components connected with wave motions in neutral atmosphere. F2 ionosphere region disturbances are developed in global scale during geomagnetic storms and characterized considerable variations in F2-region critical frequencies and heights. High frequency oblique-incidence sounding method allows us to diagnose ionospheric parameters variations in regions poorly equipped with vertical sounding stations. In this work we provide the analysis of large-scale and medium-scale traveling ionospheric disturbances (LS and MS TID's accordingly) registered during experiments from 2006 till 2011 which carried out by means of the monthly duration sets with 5-min intervals over oblique-incidence sounding paths located in the north-eastern region of Russian Federation. For the analysis we have been chosen experimental data obtained during minor and moderate geomagnetic storms. After ionograms processing maximum observed frequencies (MOF) deviations from median values were calculated. Using MOF deviations from medians the analysis of LS TID's appearance cases was carried out. Studied MOF deviations from medians can be caused by cusps on ionograms also. These cusps move with the course of time through the sequences of ionograms along upper rays from region with higher delays to region with lower delays. Such cusps on ionograms are caused by MS TID's. In this work the analysis of MS TID events registration by these cusps on ionograms was carried out. Then the comparison between LS and MS TID's appearance probability was performed. It is shown that registered MOF variations are caused by superposition of wave-like processes of different scales taken place in ionosphere during magnetic storms. This work was supported by the RFBR grants No 14-05-00259-a and No 14-05-00578-a.

  1. Recent structures and tectonic regimes of the stress-strain state of the Earth's crust in the northeastern sector of the Russian Arctic region

    NASA Astrophysics Data System (ADS)

    Imaeva, L. P.; Imaev, V. S.; Mel'nikova, V. I.; Koz'min, B. M.

    2016-11-01

    A comprehensive investigation aimed at determining seismotectonic types of destruction and the stress-strain state of the Earth's crust in the main seismogenerating structures of the Arctic-Asian seismic belt is conducted for the territory of the northeastern sector of the Russian Arctic region. Based on the degree of activity of geodynamical processes, the regional principles for ranking neotectonic structures are elaborated, and neotectonic zoning is carried out based on the substantiated differentiation of the corresponding classes. Within the limits of the Laptev Sea, Kharaulakh, and Lena-Anabar segments, we analyzed I the structural-tectonic position of the most recent structures, II the deep structure parameters, III the parameters of the active fault system, and IV the parameters of the tectonic stress field, as revealed from tectonophysical analysis of Late Cenozoic fault and fold deformations. Based on the seismological data, the mean seismotectonic deformation tensors are calculated to determine, in combination with geological and geophysical data, the orientations of the principal stress axes and to reveal the structural-tectonic regularity for tectonic regimes of the stress-strain state of the Earth's crust in the Arctic sector of the boundary between the Eurasian and North American lithospheric plates.

  2. Sheep gastrointestinal helminthiasis in the Sertão region of Paraíba State, Northeastern Brazil: prevalence and risk factors.

    PubMed

    Vieira, Vanessa Diniz; Vilela, Vinícius Longo Ribeiro; Feitosa, Thais Ferreira; Athayde, Ana Célia Rodrigues; Azevedo, Sérgio Santos; Souto, Diego Vagner de Oliveira; Silveira, Gian Libânio da; Melo, Lídio Ricardo Bezerra de

    2014-01-01

    In this study, we aimed to establish the prevalence and risk factors relating to gastrointestinal helminthiasis, and to characterize the sanitary management practiced among sheep herds in the Sertão region of the state of Paraíba, northeastern Brazil, based on factors that condition the ways of controlling these parasites in these herds. The research was carried out between April and July 2012. We visited 54 farms, where fecal and blood samples were individually collected from 465 animals. On each farm, a questionnaire was applied to gather information on variables relating to potential risk factors. The prevalence of sheep gastrointestinal helminthiasis in the region was 75.9%. At least one animal tested positive for this helminthiasis on 53 (98.1%) of the 54 farms evaluated. The eggs per gram of feces (EPG) analysis showed the following infection burdens: 51.8% with mild infection, 27.1% moderate infection, 9.9% heavy infection and 11.2% fatal infection. Among the sheep farms visited, anthelmintics were used on 81.5% (p <0.05). The most relevant risk factor in this study was the farm area, because it defines the area available for grazing animals. Properties with many animals and little pasture area, which are the most abundant type in the Sertão region of Paraíba, tend to have high prevalence of gastrointestinal helminthiasis, because the animals are more prone to reinfection. The Sertão region of Paraíba presents high prevalence of gastrointestinal helminthiasis among sheep, and the farm area is the most relevant risk factor for the development of these parasites.

  3. [INCIDENCE, PREDISPOSING RISK FACTORS FOR THE DEVELOPMENT AND SPREADING OF ACUTE INTESTINAL INFECTIONS IN THE NORTH-EASTERN REGION OF UKRAINE].

    PubMed

    Malysh, N G; Chemych, N D; Zaritsky, A M

    2016-01-01

    Using data of the branch statistical reporting of the State Sanitary and Epidemiological Service in Sumy region and Sumy Regional State Laboratory of Veterinary Medicine, the incidence rate, modern risk factors for the development and spreading of acute infectious diarrheas were determined in the North-Eastern region of Ukraine. Under the current conditions incidence rate indices of acute intestinal infections and food toxicoinfections are within the range of 159.8-193.6 per 100 thousands. pop. Seasonal and epidemical rises are associated with a species of the agent. In the etiological structure of acute diarrheal infections there are dominated viruses, of food toxicoinfections--Klebsiellae pneumoniae, Staphylococcus aureus and Enterobacter cloacae (p < 0.05). Predictors of the complication of epidemiological situation of Shigella infections are the gain in the detection of bacterially contaminated samples of milk and dairy products (r = 0.75), for food toxicoinfections caused by Klebsiellae pneumoniae and Enterobacter cloacae--pastry with cream and cooking meat products (r = 0.64; r = 0.75). Epizootic situation in the region affects on the salmonellosis incidence rate of the population (r = 0.89). There were revealed correlations between the selection of E. coli bacteria from swabs taken from the enterprises of catering, in child care centers and the levels of incidence rates of salmonellosis, acute intestinal infections of unknown etiology (r = 0.59; r = 0.60). Timely detection and sanitation of Shigella carriers are a powerful instrument to reduce the incidence rate of shigellosis (r = 0.83).

  4. A case for archaeological reconnaissance of the Cabo Catoche-Porvenir region of the northeastern Yucatan Peninsula

    NASA Technical Reports Server (NTRS)

    Duller, Charles E.

    1990-01-01

    Satellite remote sensing technology is a tool with which archaeologists can, with relative ease, survey a region that is otherwise inaccessible. The northeast corner of the Yucatan Peninsula is such an area: it is isolated and sparsely inhabited, with dense forest and extensive swamps. From Cabo Catoche inland to Cancun, this remote corner of the ancient Maya world is virtually unexplored. Recent satellite images disclose evidence of past human activity in this unexplored region and offer a compelling argument for an archaeological reconnaissance.

  5. Climatology of columnar aerosol properties and the influence of synoptic conditions: First-time results from the northeastern region of India

    NASA Astrophysics Data System (ADS)

    Gogoi, Mukunda M.; Krishna Moorthy, K.; Babu, S. Suresh; Bhuyan, Pradip K.

    2009-04-01

    Six years of spectral aerosol optical depths (AODs), from the northeastern part of India (Dibrugarh), are used to evolve a climatology for this region. The results indicate that the seasonal mean AODs at 500 nm go as high as 0.45 ± 0.05 during premonsoon season (March to May), decrease gradually through the monsoon (June to September) to reach the lowest value of 0.19 ± 0.06 during the retreating-monsoon season (October and November), and increase to 0.31 ± 0.04 in winter (December to February). The AOD spectra are generally flatter than those seen typically over continental sites of India (and elsewhere in the neighboring regions) with Ångström exponent α remaining below 1.0 during February through August, indicating a relatively low abundance of fine and accumulation mode aerosols. The columnar size distributions (CSD) retrieved from spectral AODs are, in general, bimodal with primary mode at ˜ 0.1 μm and secondary mode at ˜ 1.0 μm. High mass loading (˜309.5 ± 65.9 mg m-2) and effective radius (˜0.40 ± 0.09 μm) occur during premonsoon and are attributed to significant abundance of coarse (natural) aerosols. Cluster analysis of air mass back trajectories indicate significant transport of mineral dust from the arid regions of west Asia and northwest India across the Indo-Gangetic plains and marine aerosols advected from the Bay of Bengal contributing largely to the coarse mode aerosols during this season. On the other hand, the peculiar topography combined with the local conditions and the widespread rainfall lead to a more pristine environment during retreating-monsoon season with quite low AODs and columnar loading.

  6. Influence of season on birth weight and weaning age of indigenous Balami and imported Sudan Desert sheep in the Sahel region of Northeastern Nigeria

    NASA Astrophysics Data System (ADS)

    Alaku, O.

    1985-06-01

    Data on birth weight and age at weaning for 1,092 (609 indigenous Balami and 483 imported Sudan Desert) sheep born from 1975 to 1979 in a Government farm near Maiduguri were analysed to study the influence of season on birth weight and age at weaning in sheep reared in the sahel region of Northeastern Nigeria. The suitability of the Sudan Desert for replacing or upgrading the indigenous Balami was considered. Season, breed, sex and type of birth significantly (P<0.001) influenced birth weight, age at weaning and the average daily gain from birth to weaning of lambs. Heaviest lambs were born during the rainy season-June August. Birth weight was lowest during the dry hot season. Balami lambs were heavier at birth and were weaned earlier with greater average daily gain than the Sudan Desert (P<0.001). Ram lambs were heavier at birth and had greater daily gain than the ewes (P<0.001). Also single-born lambs were heavier at birth and were weaned earlier (P<0.001) than twins. Twining rate in Balami was almost double that in the Sudanese. Survival tended to be greater in Sudanese than in Balami. Birth, twining and survival rates were highest for the dry cold season-born lambs. The dry cold season seems the best lambing season here. In all, the local Balami proved far superior in almost all traits considered. The use of the Sudan Desert here is definitely not econmically justifiable or rational.

  7. Coxiella burnetii Seroprevalence and Risk Factors in Cattle Farmers and Farm Residents in Three Northeastern Provinces and Inner Mongolia Autonomous Region, China.

    PubMed

    Sun, Wu-Wen; Cong, Wei; Li, Mao-Hui; Wang, Chun-Feng; Shan, Xiao-Feng; Qian, Ai-Dong

    2016-01-01

    Little is known about Coxiella burnetii infection among cattle farmers and farm residents in China. Thus, the present study was conducted to detect the seroprevalence of C. burnetii infection and estimate associated risk factors among cattle farmers and farm residents in China. A cross-sectional study was designed, and sera of 362 people living or working on 106 cattle farms were tested for C. burnetii IgG and IgM antibodies by immunofluorescence assay. Overall C. burnetii seroprevalence was 35.6% (129/362, 95% CI: 30.70-40.57), and 112 participants had experienced a past infection and seventeen (4.7%) had experienced a relatively recent infection. In the final combined multilevel model, the following activities were significantly associated with presence of antibodies against C. burnetii: milking cattle, providing general healthcare to cattle, providing birth assistance, contact dead-born animals, urbanization, and presence of mice and/or rats in the stable. Moreover, presence of disinfection equipment was a significant protective factor. This is the first study addressing the seroprevalence and risk factors of C. burnetii infection in cattle farmers and farm residents in three northeastern provinces and Inner Mongolia Autonomous Region, China.

  8. Source and Delivery of Nutrients to Receiving Waters in the Northeastern and Mid-Atlantic Regions of the United States1

    PubMed Central

    Moore, Richard B; Johnston, Craig M; Smith, Richard A; Milstead, Bryan

    2011-01-01

    Abstract This study investigates nutrient sources and transport to receiving waters, in order to provide spatially detailed information to aid water-resources managers concerned with eutrophication and nutrient management strategies. SPAtially Referenced Regressions On Watershed attributes (SPARROW) nutrient models were developed for the Northeastern and Mid-Atlantic (NE US) regions of the United States to represent source conditions for the year 2002. The model developed to examine the source and delivery of nitrogen to the estuaries of nine large rivers along the NE US Seaboard indicated that agricultural sources contribute the largest percentage (37%) of the total nitrogen load delivered to the estuaries. Point sources account for 28% while atmospheric deposition accounts for 20%. A second SPARROW model was used to examine the sources and delivery of phosphorus to lakes and reservoirs throughout the NE US. The greatest attenuation of phosphorus occurred in lakes that were large relative to the size of their watershed. Model results show that, within the NE US, aquatic decay of nutrients is quite limited on an annual basis and that we especially cannot rely on natural attenuation to remove nutrients within the larger rivers nor within lakes with large watersheds relative to the size of the lake. PMID:22457578

  9. Estimate of the size and demographic structure of the owned dog and cat population living in Veneto region (north-eastern Italy).

    PubMed

    Capello, Katia; Bortolotti, Laura; Lanari, Manuela; Baioni, Elisa; Mutinelli, Franco; Vascellari, Marta

    2015-01-01

    The knowledge of the size and demographic structure of animal populations is a necessary prerequisite for any population-based epidemiological study, especially to ascertain and interpret prevalence data, to implement surveillance plans in controlling zoonotic diseases and, moreover, to provide accurate estimates of tumours incidence data obtained by population-based registries. The main purpose of this study was to provide an accurate estimate of the size and structure of the canine population in Veneto region (north-eastern Italy), using the Lincoln-Petersen version of the capture-recapture methodology. The Regional Canine Demographic Registry (BAC) and a sample survey of households of Veneto Region were the capture and recapture sources, respectively. The secondary purpose was to estimate the size and structure of the feline population in the same region, using the same survey applied for dog population. A sample of 2465 randomly selected households was drawn and submitted to a questionnaire using the CATI technique, in order to obtain information about the ownership of dogs and cats. If the dog was declared to be identified, owner's information was used to recapture the dog in the BAC. The study was conducted in Veneto Region during 2011, when the dog population recorded in the BAC was 605,537. Overall, 616 households declared to possess at least one dog (25%), with a total of 805 dogs and an average per household of 1.3. The capture-recapture analysis showed that 574 dogs (71.3%, 95% CI: 68.04-74.40%) had been recaptured in both sources, providing a dog population estimate of 849,229 (95% CI: 814,747-889,394), 40% higher than that registered in the BAC. Concerning cats, 455 of 2465 (18%, 95% CI: 17-20%) households declared to possess at least one cat at the time of the telephone interview, with a total of 816 cats. The mean number of cats per household was equal to 1.8, providing an estimate of the cat population in Veneto region equal to 663,433 (95% CI: 626

  10. REGIONAL AND STATE VIEWS OF ESTUARINE CONDITION IN NORTHEASTERN UNITED STATE BASED ON 2001 AND 2001 NATIONAL COASTAL ASSESSMENT DATA

    EPA Science Inventory

    The National Coastal Assessment (NCA) is a probability-based survey that permits assessment of estuarine conditions at national, regional, or large-system scales. Additionally, states may use these data to comply with requirements of the Clean Water Act (CWA), which mandates re...

  11. INDICATORS OF ECOLOGICAL STRESS AND THEIR EXTENT IN THE POPULATION OF NORTHEASTERN LAKES: A REGIONAL-SCALE ASSESSMENT

    EPA Science Inventory

    One of the Environmental Monitoring and Assessment Program's first projects was a survey of 345 lakes in the eight states of the Northeast, during summers of 1991-1996. This survey was the first regional-scale attempt to use a probability-based sampling design to collect biolog...

  12. Tephra Correlations of Bentonites Spanning the Cretaceous-Paleogene Boundary in the Hell Creek Region of Northeastern Montana

    NASA Astrophysics Data System (ADS)

    Banaszak, J.; Mulcahy, S. R.; Renne, P. R.; Sprain, C. J.

    2013-12-01

    The Williston Basin arguably contains the richest terrestrial record of faunal, floral, and paleoenvironmental change across the Cretaceous-Paleogene boundary. In the northwestern Williston Basin, the dominantly fluvial Hell Creek (Cretaceous) and Tullock (Paleocene) formations have yielded prolific dinosaur and mammalian fossil records. Unfortunately, discerning trends in both biotic and environmental evolution in this interval is challenging because regional correlations are hampered by rapid lateral facies transitions. A relative chronostratigraphic scheme based on coal beds has been employed for decades but is problematic because assumptions of lateral continuity and time-correlativity are unproven in many cases and demonstrably incorrect in some. Virtually all of the coal beds, however, preserve volcanic ashes that can be used as a chronotratigraphic scheme and for regional correlations. We currently recognize more than 40 distinct ashes in the ~200 m composite thickness of these two formations. The ashes are commonly less than 1 cm thick and as many as nineteen have been found in a single ~1.5 m coal bed. The ashes thus provide a robust basis for high-resolution regional correlations. Original glass shards in the ashes are ubiquitously altered to clays, hence conventional tephrochemical characterization is impossible. Instead we are performing electron microprobe analysis of feldspar and titanite, using major and selected trace elements. Phase compositional data are subjected to principal component analysis (PCA) and combined with geochronological data, two-feldspar thermometry (where applicable), phase presence/absence data, paleomagnetic polarity, and relative stratigraphic position to yield a matrix that allows discrimination of many of these ashes. The resulting chronostratigraphy will enable regional correlations with age resolution better than the ~10 ka best case afforded by 40Ar/39Ar dating. Results thus far clearly show that correlations of

  13. Analysis of clinical symptoms and selected hematological indices in hospitalized children with Ascaris lumbricoides infection from the northeastern region of Poland.

    PubMed

    Wasilewska, Jolanta; Kaczmarski, Maciej G; Sawicka-Zukowska, Małgorzata; Tomaszewska, Barbara; Majewska, Anna; Plewa, Katarzyna; Ołdak, Elzbieta; Debkowska, Katarzyna

    2011-01-01

    Ascariasis is the most common soil-transmitted helminth infection in the world. The objective of this study was to analyze the clinical symptoms and selected hematological indices of ascariasis in hospitalized children from the northeastern region of Poland. Patients in the Pediatric Ward hospitalized in the Regional Hospital in Dabrowa Białostocka in the period of 2005-2007 were included in this retrospective study. The intestinal stage of ascariasis was diagnosed on the basis of positive coprological survey performed using the decantation technique. A total of 938 patients were included in the study, 1801 stool samples were evaluated, and A. lumbricoides-positive tests were obtained from 252 children. Ascaris-positive young children (< or = 3 yrs) accounted for 3.0% of all hospitalized children, Ascaris-positive preschool-aged children (4-7 yrs) accounted for 8.1% and school-aged children (8-18 yrs) for 15.8%. Seasonal patterns were observed in the prevalence of A. lumbricoides (maximum in August-December). There was no relationship between BMI z-score, hemoglobin levels and prevalence of infection with Ascaris lumbricoides. Significant predictors of intestinal stage ascariasis in a multivariate logistic regression model were: abdominal pain as a reason for hospital admission (OR-2.19; 95% CI 1.62-2.95; p < 0.001) and age from 4 to 7 years (OR-2.0; 95% CI 1.41-2.80; p < 0.001). The prevalence rate of ascariasis was not higher in the group of patients with atopic diseases (bronchial asthma, allergic rhinitis, atopic dermatitis) and co-existing ascariasis did not affect the eosinophil counts in the peripheral blood. Ascariasis is still a current pediatric clinical problem characterized by non-specific clinical manifestations, which should be taken into consideration in the differential diagnosis of children's diseases.

  14. Spatial, seasonal trends and transboundary transport of PM2.5 inorganic ions in the Veneto region (Northeastern Italy)

    NASA Astrophysics Data System (ADS)

    Masiol, Mauro; Benetello, Francesca; Harrison, Roy M.; Formenton, Gianni; De Gaspari, Francesco; Pavoni, Bruno

    2015-09-01

    The Veneto region lies in the eastern part of the Po Valley (Italy). This is one of the hotspots in Europe for air quality, where efforts to meet the European standard for PM2.5 according to current and future legislation have been generally unsuccessful. Recent data indicating that ammonium, nitrate and sulphate account for about one third of total PM2.5 mass show that secondary inorganic aerosol (SIA) plays a key role in the exceedence of the standards. A sampling campaign for PM2.5 was carried out simultaneously in six major cities (2012-2013). The water soluble inorganic ions were quantified and data processed to: (1) investigate the seasonal trends and the spatial variations of the ionic component of aerosol; (2) identify chemical characteristics at the regional-scale and (3) assess the potential effects of long-range transport using back-trajectory cluster analysis and concentration-weighted trajectory (CWT) models. Results indicated that PM2.5 and SIA ions have an increasing gradient in concentrations from North (mountain) to South (lowland) and from East (coastal) to West (more continental), whereas K+ and Ca2+ levels are quite uniformly distributed. Similar seasonal trends in PM2.5 and ions are seen across the region. Simultaneous daily changes were observed and interpreted as a consequence of similar emission sources, secondary pollutant generation and accumulation/removal processes. Sulphate and nitrate were not directly related to the concentrations of their precursor gases and were generally largely, but not completely, neutralised by ammonium. The clustering of back-trajectories and CWT demonstrate that the long-range movement of the air masses has a major impact upon PM2.5 and ion concentrations: an area spreading from Eastern to Central Europe was identified as a main potential source for most ions. The valley sites are also heavily influenced by local emissions in slow moving northerly air masses. Finally, two episodes of high nitrate levels were

  15. reservoir operation and hydropower generation schemes for regional scale hydrological models: case study in the northeastern united states

    NASA Astrophysics Data System (ADS)

    Ehsani, N.; Vorosmarty, C. J.; Fekete, B. M.; Rosenzweig, B.

    2013-12-01

    As part of the development of the Northeast Regional Earth System Model (NE-RESM), we are developing an integrated hydrologic modeling framework that incorporates various aspects of the coupled human-hydrologic system, from supply to demand, into a single framework. This framework provides temporally and spatially explicit information on the regional water system under different scenarios of climate, population, and land use/ land cover change. To support these efforts, we have incorporated two new modules into the Water Balance Model (WBM) that simulate reservoir operation and calculate the hydropower production from dams. Dams and reservoirs are key characteristics of the modern hydrologic system, with a particular impact on natural stream flow, sediment flux, thermal characteristics and biogeochemical fluxes of rivers. In the Northeast Region of the United States alone, the National Inventory of Dams (NID) lists over 12000 reservoirs. Depending on site-specific characteristics of the dam, its watershed and its intended purpose, each will have a specific optimum operating rule. Since no comprehensive dataset of these operating rules exists, we have to simulate them. We developed an Artificial Neural Network and used data from 35 dams for calibration. Approximately 60 % of the dataset was dedicated to training process, 20 % to validation and the other 20 % used for testing. If (t) represents current time, we use three sets of inputs; inflow [It , It-1 , It-2], release in previous months [Rt-1 , Rt-2] and month (Mt), to calculate release from reservoir (Rt). We also used a simple continuity equation for reservoirs by considering the maximum (from NID) and minimum reservoir storage to improve the model's performance in extreme wet and dry events. Using results from WBM we show how reservoirs regionally alter discharge in streams of Northeast United States compared to their natural state. We also are assessing the effects of climate change on water availability and

  16. Using online database for landslide susceptibility assessment with an example from the Veneto Region (north-eastern Italy).

    NASA Astrophysics Data System (ADS)

    Floris, Mario; Squarzoni, Cristina; Zorzi, Luca; D'Alpaos, Andrea; Iafelice, Maria

    2010-05-01

    Landslide susceptibility maps describe landslide-prone areas by the spatial correlation between landslides and related factors, derived from different kinds of datasets: geological, geotechnical and geomechanical maps, hydrogeological maps, landslides maps, vector and raster terrain data, real-time inclinometer and pore pressure data. In the last decade, thanks to the increasing use of web-based tools for management, sharing and communication of territorial information, many Web-based Geographical Information Systems (WebGIS) were created by local governments or nations, University and Research Centres. Nowadays there is a strong proliferation of geological WebGIS or GeoBrowser, allowing free download of spatial information. There are global Cartographical Portals that provide a free download of DTM and other vector data related to the whole planet (http://www.webgis.com). At major scale, there are WebGIS regarding entire nation (http://www.agiweb.org), or specific region of a country (http://www.mrt.tas.gov.au), or single municipality (http://sitn.ne.ch/). Moreover, portals managed by local government and academic government (http://turtle.ags.gov.ab.ca/Peace_River/Site/) or by a private agency (http://www.bbt-se.com) are noteworthy. In Italy, the first national projects for the creation of WebGIS and web-based databases begun during the 1980s, and evolved, through years, to the present number of different WebGIS, which have different territorial extensions: national (Italian National Cartographical Portal, http://www.pcn.minambiente.it; E-GEO Project, http://www.egeo.unisi.it), interregional (River Tiber Basin Authority, www.abtevere.it ), and regional (Veneto Region, www.regione.veneto.it). In this way we investigated most of the Italian WebGIS in order to verify their geographic range and the availability and quality of data useful for landslide hazard analyses. We noticed a large variability of the accessing information among the different browsers. In

  17. Predicting ecosystem dynamics at regional scales: an evaluation of a terrestrial biosphere model for the forests of northeastern North America.

    PubMed

    Medvigy, David; Moorcroft, Paul R

    2012-01-19

    Terrestrial biosphere models are important tools for diagnosing both the current state of the terrestrial carbon cycle and forecasting terrestrial ecosystem responses to global change. While there are a number of ongoing assessments of the short-term predictive capabilities of terrestrial biosphere models using flux-tower measurements, to date there have been relatively few assessments of their ability to predict longer term, decadal-scale biomass dynamics. Here, we present the results of a regional-scale evaluation of the Ecosystem Demography version 2 (ED2)-structured terrestrial biosphere model, evaluating the model's predictions against forest inventory measurements for the northeast USA and Quebec from 1985 to 1995. Simulations were conducted using a default parametrization, which used parameter values from the literature, and a constrained model parametrization, which had been developed by constraining the model's predictions against 2 years of measurements from a single site, Harvard Forest (42.5° N, 72.1° W). The analysis shows that the constrained model parametrization offered marked improvements over the default model formulation, capturing large-scale variation in patterns of biomass dynamics despite marked differences in climate forcing, land-use history and species-composition across the region. These results imply that data-constrained parametrizations of structured biosphere models such as ED2 can be successfully used for regional-scale ecosystem prediction and forecasting. We also assess the model's ability to capture sub-grid scale heterogeneity in the dynamics of biomass growth and mortality of different sizes and types of trees, and then discuss the implications of these analyses for further reducing the remaining biases in the model's predictions.

  18. [Border effect and physiological characteristics of broomcorn millet under film mulching on ridge-furrow for harvesting rainwater model in the semi-arid region of Northern Shaanxi, China].

    PubMed

    Qu, Yang; Su, Wang; Li, Cui; Gao, Jin-Feng; Gao, Xiao-Li; Wang, Peng-Ke; Feng, Bai-Li; Chai, Yan

    2014-03-01

    To explore the border effect and physiological characteristic of broomcorn millet growing under different film mulching on ridge-furrow for harvesting rainwater models in the semi-arid region of Northern Shaanxi, China, a three-year field experiment was conducted with four different widths of ridge and furrow, and the bare land flat sowing as the control (NM). The width of ridge and furrow varied as ridge: furrow = 40 cm: 40 cm (P40), 60 cm: 60 cm (P60), 80 cm: 80 cm (P80), and 100 cm:100 cm (P100). The results showed that the wider the width of furrow and ridge was, the stronger the border advantage and the border effect index of the yield were. With the increase in width of furrow and ridge, the yield increasing effect of side rows increased with the maximum of 207.7%, and the yield increasing effect of middle rows decreased with the minimum of 10.3%. P60 reached the highest yield within three years. The yield contribution rate of side rows was higher than that of middle rows (P < 0.05). The chlorophyll contents, Ch1 a/Ch1 b, and photosynthetic rate of side rows were higher than those of middle rows among the different harvesting rainwater models. The wider the width of furrow and ridge was, the stronger the photosynthetic capacity of side rows was, and the weaker the photosynthetic capacity of middle rows was. The optimal type of ridge and furrow was P60 in the semi-arid region of Northern Shaanxi.

  19. Geochemistry of mine tailings and behavior of arsenic at Kombat, northeastern Namibia.

    PubMed

    Sracek, O; Mihaljevič, M; Kříbek, B; Majer, V; Filip, J; Vaněk, A; Penížek, V; Ettler, V; Mapani, B

    2014-08-01

    The mine tailings at Kombat, in semiarid northeastern Namibia, were investigated by the combination of solid-phase analyses, mineralogical methods, leaching tests, and speciation modeling. Dissolution of the most abundant primary sulfides, chalcopyrite and galena, released copper and lead which were adsorbed onto ferric oxyhydroxides or precipitated in the form of malachite, Cu2CO3(OH)2, and cerussite, PbCO3, respectively. Arsenic released from arsenopyrite was incorporated into ferric oxyhydroxides. Based on sequential extraction and (57)Fe Mössbauer spectroscopy, a large amount of ferric iron is present as low solubility hematite and goethite formed rapidly (<10 years) under warm semiarid climatic conditions, and arsenic in these phases is relatively tightly bound. It seems that Cu and especially Pb in carbonate minerals represent a more serious environmental risk. Immobilization of As in hematite has implications for other mining sites in regions with similar climatic conditions because this process results in long-term immobilization of As.

  20. Ionospheric response to geomagnetic disturbances in the north-eastern region of Asia during the minimum of 23rd cycle of solar activity

    NASA Astrophysics Data System (ADS)

    Kurkin, V. I.; Pirog, O. M.; Polekh, N. M.; Mikhalev, A. V.; Poddelsky, I. N.; Stepanov, A. E.

    2008-12-01

    We present the results of studies of the subauroral and mid-latitude ionosphere variations in the north-eastern region of Asia. We used the data from network of vertical and oblique-incidence sounding ionosondes and optical measurements. Long-term experiments on the radio paths Magadan-Irkutsk and Norilsk-Irkutsk were carried out within the period 2005-2007. Vertical sounding stations operated in standard regime. Observation of airglow near Irkutsk was provided by the zenith photometer that measured intensities of 557.7 and 630.0 nm atomic oxygen emissions. The results may be summarized as follows. (1) Large daytime negative disturbances are observed during the main and recovery phases mainly at high latitudes, whereas the positive disturbances observed during the main phase at mid latitudes. The disturbances changed their sign between Yakutsk and Irkutsk. (2) During the main and recovery storm phases the fall of foF2 associated with the equatorward wall of the main ionospheric trough is observed in the afternoon and evening. (3) Fluctuations of the electron density more intensive at mid latitudes during the storm main phase are observed during all considered periods. They are classed as traveling ionospheric disturbances (TID). Such sharp gradients of electron density are responsible for the strong changes in the characteristics of the radio wave propagation, particularity MOF. (4) A large-scale ionospheric disturbance is noted at the meridional chain of ionosonds in December 2006 as the sharp increase of foF2. It appears in the evening in the minimum of Dst at high latitude and propagate to equator. (5) A maximum of 630 nm emission above Irkutsk corresponds to the foF2 increase. (6) The obtained experimental data on the net of vertical and oblique-incidence sounding with high time resolution show that such net is the effective facility to study the conditions of the radio wave propagation and can be used for the diagnostic of the ionosphere.

  1. Fluvial basin history in the northeastern Mediterranean region underlies dispersal and speciation patterns in the genus Dugesia (Platyhelminthes, Tricladida, Dugesiidae).

    PubMed

    Solà, Eduard; Sluys, Ronald; Gritzalis, Konstantinos; Riutort, Marta

    2013-03-01

    In this study we analyzed the phylogenetic relationships of eastern Mediterranean freshwater planarians of the genus Dugesia, estimated divergence times for the various clades, and correlated their phylogeographic patterns with geological and paleoclimatic events, in order to discover which evolutionary processes have shaped the present-day distribution of these animals. Specimens were collected from freshwater courses and lakes in continental and insular Greece. Genetic divergences and phylogenetic relationships were inferred by using the mitochondrial gene subunit I of cytochrome oxidase (COI) and the nuclear ribosomal internal transcribed spacer-1 (ITS-1) from 74 newly collected individuals from Greece. Divergence time estimates were obtained under a Bayesian framework, using the COI sequences. Two alternative geological dates for the isolation of Crete from the mainland were tested as calibration points. A clear phylogeographic pattern was present for Dugesia lineages in the Eastern Mediterranean. Morphological data, combined with information on genetic divergences, revealed that eight out of the nine known species were represented in the samples, while additional new, and still undescribed species were detected. Divergence time analyses suggested that Dugesia species became isolated in Crete after the first geological isolation of the island, and that their present distribution in the Eastern Mediterranean has been shaped mainly by vicariant events but also by dispersal. During the Messinian salinity crisis these freshwater planarians apparently were not able to cross the sea barrier between Crete and the mainland, while they probably did disperse between islands in the Aegean Sea. Their dependence on freshwater to survive suggests the presence of contiguous freshwater bodies in those regions. Our results also suggest a major extinction of freshwater planarians on the Peloponnese at the end of the Pliocene, while about 2Mya ago, when the current Mediterranean

  2. Metal-Induced Production of a Novel Bioadsorbent Exopolysaccharide in a Native Rhodotorula mucilaginosa from the Mexican Northeastern Region.

    PubMed

    Garza-Gonzalez, Maria Teresa; Gonzalez Garza, Maria Teresa; Barboza Perez, Daniel; Vazquez Rodriguez, Augusto; Garcia-Gutierrez, Domingo Ixcoatl; Zarate, Xristo; Cantú Cardenas, Maria Elena; Urraca-Botello, Ludwing Ilytch; Lopez-Chuken, Ulrico Javier; Trevino-Torres, Alberto Ludovico; Cerino-Córdoba, Felipe de Jesus; Medina-Ruiz, Pavel; Villarreal-Chiu, Juan Francisco; Morones-Ramirez, Jose Ruben

    2016-01-01

    There is a current need to develop low-cost strategies to degrade and eliminate industrially used colorants discharged into the environment. Colorants discharged into natural water streams pose various threats, including: toxicity, degradation of aesthetics and inhibiting sunlight penetration into aquatic ecosystems. Dyes and colorants usually have complex aromatic molecular structures, which make them very stable and difficult to degrade and eliminate by conventional water treatment systems. The results in this work demonstrated that heavy metal-resistant Rhodotorula mucilaginosa strain UANL-001L isolated from the northeast region of Mexico produce an exopolysaccharide (EPS), during growth, which has colorant adsorption potential. The EPS produced was purified by precipitation and dialysis and was then physically and chemically characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and chemical elemental analysis. Here, the ability of the purified EPS produced to adsorb methylene blue (MB), which served as a model colorant, is studied. MB adsorption by the EPS is found to follow Langmuir Adsorption Isotherm kinetics at 25°C. Further, by calculating the Langmuir constant the adsorption capabilities of the EPS produced by the Rhodotorula mucilaginosa strain UANL-001L is compared to that of other adsorbents, both, microbially produced and from agroindustrial waste. The total adsorption capacity of the EPS, from the Rhodotorula mucilaginosa strain UANL-001L, was found to be two-fold greater than the best bioadsorbents reported in the literature. Finally, apart from determining which heavy metals stimulated EPS production in the strain, the optimal conditions of pH, heavy metal concentration, and rate of agitation of the growing culture for EPS production, was determined. The EPS reported here has the potential of aiding in the efficient removal of colorants both in water treatment plants and in situ in natural water streams.

  3. Metal-Induced Production of a Novel Bioadsorbent Exopolysaccharide in a Native Rhodotorula mucilaginosa from the Mexican Northeastern Region

    PubMed Central

    Vazquez Rodriguez, Augusto; Garcia-Gutierrez, Domingo Ixcoatl; Zarate, Xristo; Cantú Cardenas, Maria Elena; Urraca-Botello, Ludwing Ilytch; Lopez-Chuken, Ulrico Javier; Trevino-Torres, Alberto Ludovico; Cerino-Córdoba, Felipe de Jesus; Medina-Ruiz, Pavel; Villarreal-Chiu, Juan Francisco; Morones-Ramirez, Jose Ruben

    2016-01-01

    There is a current need to develop low-cost strategies to degrade and eliminate industrially used colorants discharged into the environment. Colorants discharged into natural water streams pose various threats, including: toxicity, degradation of aesthetics and inhibiting sunlight penetration into aquatic ecosystems. Dyes and colorants usually have complex aromatic molecular structures, which make them very stable and difficult to degrade and eliminate by conventional water treatment systems. The results in this work demonstrated that heavy metal-resistant Rhodotorula mucilaginosa strain UANL-001L isolated from the northeast region of Mexico produce an exopolysaccharide (EPS), during growth, which has colorant adsorption potential. The EPS produced was purified by precipitation and dialysis and was then physically and chemically characterized by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and chemical elemental analysis. Here, the ability of the purified EPS produced to adsorb methylene blue (MB), which served as a model colorant, is studied. MB adsorption by the EPS is found to follow Langmuir Adsorption Isotherm kinetics at 25°C. Further, by calculating the Langmuir constant the adsorption capabilities of the EPS produced by the Rhodotorula mucilaginosa strain UANL-001L is compared to that of other adsorbents, both, microbially produced and from agroindustrial waste. The total adsorption capacity of the EPS, from the Rhodotorula mucilaginosa strain UANL-001L, was found to be two-fold greater than the best bioadsorbents reported in the literature. Finally, apart from determining which heavy metals stimulated EPS production in the strain, the optimal conditions of pH, heavy metal concentration, and rate of agitation of the growing culture for EPS production, was determined. The EPS reported here has the potential of aiding in the efficient removal of colorants both in water treatment plants and in situ in natural water streams. PMID

  4. The contribute of DInSAR techniques to landslide hazard evaluation in mountain and hilly regions: a case study from Agno Valley (North-Eastern Italian Alps)

    NASA Astrophysics Data System (ADS)

    De Agostini, A.; Floris, M.; Pasquali, P.; Barbieri, M.; Cantone, A.; Riccardi, P.; Stevan, G.; Genevois, R.

    2012-04-01

    In the last twenty years, Differential Synthetic Aperture Radar Interferometry (DInSAR) techniques have been widely used to investigate geological processes, such as subsidence, earthquakes and landslides, through the evaluation of earth surface displacements caused by these processes. In the study of mass movements, contribution of interferometry can be limited due to the acquisition geometry of RADAR images and the rough morphology of mountain and hilly regions which represent typical landslide-prone areas. In this study, the advanced DInSAR techniques (i.e. Small Baseline Subset and Persistent Scatterers techniques), available in SARscape software, are used. These methods involve the use of multiple acquisitions stacks (large SAR temporal series) allowing improvements and refinements in landslide identification, characterization and hazard evaluation at the basin scale. Potential and limits of above mentioned techniques are outlined and discussed. The study area is the Agno Valley, located in the North-Eastern sector of Italian Alps and included in the Vicenza Province (Veneto Region, Italy). This area and the entire Vicenza Province were hit by an exceptional rainfall event on November 2010 that triggered more than 500 slope instabilities. The main aim of the work is to verify if spatial information available before the rainfall event, including ERS and ENVISAT RADAR data from 1992 to 2010, were able to predict the landslides occurred in the study area, in order to implement an effectiveness forecasting model. In the first step of the work a susceptibility analysis is carried out using landslide dataset from the IFFI project (Inventario Fenomeni Franosi in Italia, Landslide Italian Inventory) and related predisposing factors, which consist of morphometric (elevation, slope, aspect and curvature) and non-morphometric (land use, distance of roads and distance of river) factors available from the Veneto Region spatial database. Then, to test the prediction, the

  5. Influence of groundwater on the degradation of irrigated soils in a semi-arid region, the inner delta of the Niger River, Mali

    NASA Astrophysics Data System (ADS)

    Valenza, A.; Grillot, J. C.; Dazy, J.

    2000-08-01

    The problem of soil degradation through alkalinization/salinization in an irrigated area with a semi-arid climate was examined in the inner delta of the Niger River, Mali, by the study of groundwater hydraulics and hydrochemistry in an area recharged by irrigation water. On the basis of data analysis on various scales, it is concluded that the current extent of the surface saline soils is due to a combination of three factors: (1) the existence of ancient saline soils (solonchaks) resulting from the creation of a broad sabkha west of the former course of the Niger River, now called the Fala of Molodo. These saline crusts were gradually deposited during the eastward tilting of the tectonic block that supports the Niger River; (2) the irrigation processes during the recent reflooding of the Fala of Molodo (river diversion in 1950). These used very poorly mineralized surface water but reintroduced into the alluvial groundwater system - generally of a low permeability (K=10-6 m s-1) - salts derived from the ancient solonchaks; and (3) the redeposition of the dissolved salts on the surface due to the intense evapotranspiration linked to the present Sahelian climate. In this context, only efficient artificial draining of subsurface alluvial groundwater can eliminate most of the highly mineralized flow and thus reduce the current saline deposits.

  6. Capability of a regional climate model to simulate climate variables requested for water balance computation: a case study over northeastern France

    NASA Astrophysics Data System (ADS)

    Boulard, Damien; Castel, Thierry; Camberlin, Pierre; Sergent, Anne-Sophie; Bréda, Nathalie; Badeau, Vincent; Rossi, Aurélien; Pohl, Benjamin

    2016-05-01

    This paper documents the capability of the ARW/WRF regional climate model to regionalize near-surface atmospheric variables at high resolution (8 km) over Burgundy (northeastern France) from daily to interannual timescales. To that purpose, a 20-year continuous simulation (1989-2008) was carried out. The WRF model driven by ERA-Interim reanalyses was compared to in situ observations and a mesoscale atmospheric analyses system (SAFRAN) for five near-surface variables: precipitation, air temperature, wind speed, relative humidity and solar radiation, the last four variables being used for the calculation of potential evapotranspiration (ET0). Results show a significant improvement upon ERA-Interim. This is due to a good skill of the model to reproduce the spatial distribution for all weather variables, in spite of a slight over-estimation of precipitation amounts mostly during the summer convective season, and wind speed during winter. As compared to the Météo-France observations, WRF also improves upon SAFRAN analyses, which partly fail at showing realistic spatial distributions for wind speed, relative humidity and solar radiation—the latter being strongly underestimated. The SAFRAN ET0 is thus highly under-estimated too. WRF ET0 is in better agreement with observations. In order to evaluate WRF's capability to simulate a reliable ET0, the water balance of thirty Douglas-fir stands was computed using a process-based model. Three soil water deficit indexes corresponding to the sum of the daily deviations between the relative extractible water and a critical value of 40 % below which the low soil water content affects tree growth, were calculated using the nearest weather station, SAFRAN analyses weather data, or by merging observation and WRF weather variables. Correlations between Douglas-fir growth and the three estimated soil water deficit indexes show similar results. These results showed through the ET0 estimation and the relation between mean annual SWDI

  7. Evaluating the influence of geo-environmental factors on gully erosion in a semi-arid region of Iran: An integrated framework.

    PubMed

    Rahmati, Omid; Tahmasebipour, Naser; Haghizadeh, Ali; Pourghasemi, Hamid Reza; Feizizadeh, Bakhtiar

    2017-02-01

    Despite the importance of soil erosion in sustainable development goals in arid and semi-arid areas, the study of the geo-environmental conditions and factors influencing gully erosion occurrence is rarely undertaken. As effort to this challenge, the main objective of this study is to apply an integrated approach of Geographic Object-Based Image Analysis (GEOBIA) together with high-spatial resolution imagery (SPOT-5) for detecting gully erosion features at the Kashkan-Poldokhtar watershed, Iran. We also aimed to apply a Conditional Probability (CP) model for establishing the spatial relationship between gullies and the Geo-Environmental Factors (GEFs). The gully erosion inventory map prepared using GEOBIA and field surveying was randomly partitioned into two subsets: (1) part 1 that contains 70% was used in the training phase of the CP model; (2) part 2 is a validation dataset (30%) for validation of the model and to confirm its accuracy. Prediction performances of the GEOBIA and CP model were checked by overall accuracy and Receiver Operating Characteristics (ROC) curve methods, respectively. In addition, the influence of all GEFs on gully erosion was evaluated by performing a sensitivity analysis model. The validation findings illustrated that overall accuracy for GEOBIA approach and the area under the ROC curve for the CP model were 92.4% and 89.9%, respectively. Also, based on sensitivity analysis, soil texture, drainage density, and lithology represent significantly effects on the gully erosion occurrence. This study has shown that the integrated framework can be successfully used for modeling gully erosion occurrence in a data-poor environment.

  8. The cactus effect: an alternative to the lupin effect for increasing ovulation rate in sheep reared in semi-arid regions?

    PubMed

    Rekik, M; Gonzalez-Bulnes, A; Lassoued, N; Ben Salem, H; Tounsi, A; Ben Salem, I

    2012-04-01

    The present study evaluated the effects of supplementation with cactus cladodes on follicular dynamics and ovulatory response of sheep reared in semi-arid areas. A total of 76 ewes were distributed into two equal groups supplemented with either concentrated feed or cactus cladodes. After 30 days of supplementation, no differences were found between feeding regimens on the final live weight (LW; 41.5 ± 0.6 and 42.1 ± 0.7 kg in the Concentrate and Cactus groups respectively) and body condition score (BCS; 1.8 ± 0.3 and 1.8 ± 0.4 for Concentrate and Cactus group respectively). Moreover, no differences were found between the initial and the final values of both LW and BCS; thus, there were no effects of supplementation on any of both parameters. Analysis of follicular population showed that, during the follicular phase induced by ram effect, the number of follicles reaching ovulatory size increased in both groups. However, the number was always higher in Cactus ewes and, at oestrus, Cactus ewes had 1.6 ± 0.2 and Concentrate sheep had 1.2 ± 0.2 large follicles (p < 0.05). Thereafter, ovulation rate was affected by duration of supplementation; being higher in sheep fed with cactus for 6-10 days (1.7 ± 0.1) than in ewes supplied with cactus for more than 11 days (1.3 ± 0.1; p < 0.05), in sheep fed with concentrate for 6-10 days (1.2 ± 0.1; p < 0.01) and even than in individuals subjected to classical flushing with concentrate (1.3 ± 0.1; p < 0.05).

  9. Using multi-component hydrochemical pattern for water balance calculations of intricate water resources in semi-arid regions - a case study in Wadi Al Arab, Jordan.

    NASA Astrophysics Data System (ADS)

    Siebert, Christian; Rödiger, Tino; Geyer, Stefan; Subah, Ali; Guttman, Yossi

    2013-04-01

    Groundwater harvesting in the semi-arid Wadi al Arab, located in the NW most corner of the Kingdom of Jordan, is supposed to be sustainable. However, since implementation of intense well fields, which take water from the Cretaceous A7/B2 aquifer, springs along the wadi course dried out and groundwater table dropped locally tremendous. To overcome the uncertainties in qualitatively and quantitatively characterising that water resource, a multi-component hydrochemical study was carried out within the SMART-project, which was also used to provide reliable boundary conditions to build up a transient numerical flow model. Wadi Al Arab represents a multi-aquifer system, with unknown interactions between the Cenozoic and Cretaceous aquifers. The exact identification and qualitatively characterization of the different groundwater bodies, the definition of their flow regimes and the recharge rate is a necessary step to calculate a reliable water balance and a rational policy of water management. Inter-aquifer flow prevents the benchmark treatment of the groundwater bodies and its detection by classical methods is an almost impossible task. In order to overcome these difficulties, the main known components of the multi-aquifer system were analysed for REY (REE+ Yttrium) abundance, major elements and for stable isotopes of water (δ18O and δD). The different waters in the area were than classified considering these parameters. This enabled identifying their respective replenishment areas and to elucidate the mixing processes controlled by structural features. This study shows that REY patterns are a powerful tool to decipher the lithology of the catchment area and the intricate patterns of flow paths of the aquifer systems. These information allow the correct definition of boundary conditions for a successful hydraulic modelling.

  10. Origin of spinel lamella and/or inclusions in olivine of harzburgite form the Pauza ultramafic rocks from the Kurdistan region, northeastern Iraq

    NASA Astrophysics Data System (ADS)

    Mohammad, Y.; Maekawa, H.; Karim, K.

    2009-04-01

    Exsolution lamellae and octahedral inclusions of chromian spinel occur in olivine of harzburgite of the Pauza ultramafic rocks, Kurdistan region, northeastern Iraq. The lamella is up to 80μm long and up to 50 μm wide. The lamellae and octahedral inclusions of chromian spinel are distributed heterogeneously in the host olivine crystal. They are depleted in Al2O3 relative to the subhedral spinel grains in the matrix and spinel lamella in orthopyroxene. Olivine (Fo92 - 93) with spinel lamellae occurs as fine-grained crystals around orthopyroxene, whereas olivine (Fo90-91) free from spinel is found in matrix. Based on back-scattered images analyses, enrichments of both Cr # and Fe+3 in the chromian spinel lamella in olivine (replacive olivine) relative to that in adjacent orthopyroxene. As well as the compositions of chromian spinel lamellae host olivine are more Mg-rich than the matrix olivine. Furthermore the restriction of olivine with spinel lamellae and octahedral inclusions on around orthopyroxene, and the similarity of spinel lamella orientations in both olivine and adjacent orthopyroxene. This study concludes that the spinel inclusions in olivine are remnant (inherited from former orthopyroxene) spinel exsolution lamella in orthopyroxene, that has been formed in upper mantle conditions ( T = 1200 °C, P = 2.5 GPa ). Replacive olivine are formed by reaction of ascending silica poor melt and orthopyroxene in harzburgite as pressure decrease the solubility of silica-rich phase (orthopyroxene) in the system increase, therefore ascending melt dissolve pyroxene with spinel exsolution lamella and precipitate replacive olivine with spinel inclusions. We can conclude that the olivines with spinel lamella are not necessary to be original and presenting ultrahigh-pressure and/or ultra deep-mantle conditions as previously concluded. It has been formed by melting of orthopyroxene (orthopyroxene with spinel exsolution lamella = olivine with spinel lamellae and octahedral

  11. Trends of temperature and precipitation and their impact on grapewine phenology and production of in a Mediterranean vineyard region of Northeastern Spain

    NASA Astrophysics Data System (ADS)

    Ramos, M. C.; Jones, G. V.; Martínez-Casasnovas, J. A.

    2009-04-01

    The present analysis tries to contribute to the knowledge and impacts of climate change on agriculture, in particular in dryland areas of the Mediterranean NE Spain. The analysis was carried out in the Penedès region, located in Northeastern Spain (Barcelona province). In this area, vineyards have cultivated for centuries and at present represent about 80% of the cultivated area, most of them as rainfed agriculture, without irrigation. In order to analyse climate change impacts on grape development and production, the trends of daily rainfall and temperature were analyzed for the whole year and for the growing season, as well as some bioclimatic indexes (Hugling and Winkler index) using a long data set belonging to Vilafranca del Penedès for the period 1952-2006, and shorter series belonging to the observatories of Sant Sadurní d'Anoia, Sant Martí Sarroca, Els Hostalest de Pierola for the last 12 years (1996-2007). Phenology dates and production for the last 12 years for the main varieties cultivated in the area (Macabeo, Xarello, Parellada and Chardonnay) were analysed in relation to all the climatic analysed parameters. The study revealed warming trends with higher increases in the maximum temperatures (0.04°C/year) than in the minimum temperatures (0.03°C/year), and a significant increase in the number of days with temperatures higher than 30°C (0.43 days/year). Changes were also reproduced during the grape growing season. The increase of temperature has its influence on higher evapotranspiration ratios, which implies less effective water for crop development. Annual rainfall showed high variability from year to year and did not change significantly with time not at annual level either during the growing season. However, the precipitation of the main rainfall periods (spring and autumn) shows opposite trends, decreasing precipitation in spring and increasing in autumn. According to the vine phenological stages a significant decrease of precipitation

  12. Geology of northeastern Montana

    USGS Publications Warehouse

    Collier, Arthur J.

    1919-01-01

    A large region in northeastern Montana has never been thoroughly explored by geologists, owing to the fact that it is a part of the Great Plains and the belief that it is too monotonous and uninteresting to tempt anyone to turn aside from the pronounced geologic features a little farther west, for which Montana is noted. This region includes parts of Sheridan, Valley, Phillips, and Blaine counties. Its investigation was begun by Smith in 1908, when he made a geologic survey of the Fort Peck Indian Reservation. Beekly explored a strip of land along the Montana-North Dakota line from Missouri River to the international boundary, and Bauer examined the townships in which Plentywood and Scobey are situated. Their results are here included with those of the writer, who during the field seasons of 1915 and 1916 was engaged in an investigation of the lignite resources of the remainder of this region, which extends from a line within 12 miles of the Montana-North Dakota boundary westward about 200 miles.

  13. Melioidosis, Northeastern Brazil

    PubMed Central

    Rolim, Dionne Bezerra; Vilar, Dina Cortez Feitosa Lima; Sousa, Anastacio Queiroz; Miralles, Iracema Sampaio; Almeida de Oliveira, Diana Carmen; Harnett, Gerry; O'Reilly, Lyn; Howard, Kay; Sampson, Ian

    2005-01-01

    Melioidosis was first recognized in northeastern Brazil in 2003. Confirmation of additional cases from the 2003 cluster in Ceará, more recent cases in other districts, environmental isolation of Burkholderia pseudomallei, molecular confirmation and typing results, and positive serosurveillance specimens indicate that melioidosis is more widespread in northeastern Brazil than previously thought. PMID:16229782

  14. Discriminating Between Tectonic and Climatic Controls on Early Hominin Paleoenvironments From the Koobi Fora Region, Northeastern Turkana Basin, Kenya: Part II

    NASA Astrophysics Data System (ADS)

    Quinn, R. L.; Lepre, C. J.

    2004-12-01

    Global climate is often elected as a catalyst for environmental change and used to characterize selective pressures acting on Plio-Pleistocene African hominins. Vrba's Habitat Theory (1992) and Pott's Variability Selection (1998) credit mammalian evolutionary pattern and process to global climate regulated by orbital forcing. Feibel (1999: 276) argues the need for a middle ground, tethering the "global-scale climatic phenomena" to "environmental change, habitat shift, and biotic evolution" and offers the basin as a scale for analysis. Feibel suggests that all basins are not created equal, and will respond to climate change with different sensitivities and thresholds. As such, interpretations of climate proxies must account for differences in basin size, climatic regime(s), topography, geology, and water availability when drawing relationships to global phenomena. Here we examine pedogenic carbonate isotopes (d13C, d18O) from the Plio-Pleistocene Koobi Fora Region to elucidate the differential influences of climate, tectonics, and deposition on ecological factors of early hominin evolution in the northeastern Turkana Basin of Kenya. One of the richest Plio-Pleistocene fossil localities in Africa, Koobi Fora has served as a setting for hominin evolution between 4.0 and 1.0 Ma. Numerous paleosols, stratigraphically controlled by tuffaceous marker beds, are preserved in the Plio-Pleistocene sediments of the Koobi Fora Formation. Cerling and others (1988) and Wynn (2000) conducted isotopic studies of pedogenic carbonates from the Plio-Pleistocene Omo Group deposits of the Turkana Basin. With these data Wynn (2004) demonstrates stepwise d13C shifts over the last 4.0 Ma, with marked events at 2.5 and 1.8 Ma, and interprets increased aridity on a basin scale due to comparable records on the east and west side of present Lake Turkana. In this study, we increased the sample size of the current database and conducted widespread sampling of synchronous lateral horizons in the

  15. Replacing fallow with continuous cropping reduces crop water productivity of semiarid wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water supply frequently limits crop yield in semiarid cropping systems; water deficits can restrict yields in drought-affected subhumid regions. In semiarid wheat (Triticum aestivumL.)-based cropping systems, replacing an uncropped fallow period with a crop can increase precipitation use efficiency ...

  16. Assessment of vulnerability in karst aquifers using a quantitative integrated numerical model: catchment characterization and high resolution monitoring - Application to semi-arid regions- Lebanon.

    NASA Astrophysics Data System (ADS)

    Doummar, Joanna; Aoun, Michel; Andari, Fouad

    2016-04-01

    fast infiltration component. A series of laboratory tests were performed to acquire physical values to be used as a benchmark for model parameterization, such as laboratory tests on soils for conductivity at saturation and grain size analysis. Time series used for input or calibration were collected and computed from continuous high resolution monitoring of climatic data, moisture variation in the soil, and discharge at the investigated spring. This similar model approach used on a catchment site in Germany is to be applied and validated on two pilot karst catchments in Lebanon governed by semi-arid climatic conditions. References Doummar J., Sauter M., Geyer T., 2012. Simulation of flow processes in a large scale karst system with an integrated catchment model (Mike She) - Identification of relevant parameters influencing spring discharge. Journal of Hydrology, v. 426-427- p 112-123. Jukić, D., and Denić-Jukić, V., 2009. Groundwater balance estimation in karst by using a conceptual rainfall-runoff model. Journal of Hydrology, v. 373- p 302-315

  17. Neotectonics in northeastern Brazil

    NASA Astrophysics Data System (ADS)

    Bezerra, Francisco Hilario Rego

    The thesis describes neotectonic deformation in the continental intraplate region of northeastern Brazil and explores its links with modern seismicity. The region, which is under E-W-oriented compression and N-S-oriented extension, shows shallow earthquake swarms which last for several years and include 5.0-5.2 mb events. Remote sensing, borehole and geophysical data, in conjunction with field structural information, indicate a continuous faulting process since the Miocene which has reactivated Cretaceous faults and Precambrian shear zones or in places generated new faults which cut across existing structures. Three main sets of faults are recognised across the area: a NE-striking set, a NW-striking set and a N-striking set. The first and the second sets are pervasive and their cross-cutting relationships show that they locally form a conjugate set and display both a strike-slip and a dip-slip component of movement. They have generated troughs filled by as much as 260 m of Cainozoic sediments. Radiocarbon dating shows that some of the faults slipped as recently as 4,041-3,689 cal. yr BP. Although the elevation of coastal deposits is consistent with the predictions of glacioisostatic models for the area, tectonic influence can be detected notably near the Carnaubais fault, where rapid emergence by at least 5 m to the east of Sao Bento occurred 4,080-2,780 cal. yr BP. Secondary ground failure, which includes hydroplastic deformation, liquefaction and landslides, can be seen in Quaternary alluvial sediments and is reported in the historical record. The present data show that the potential for large earthquakes in northeastern Brazil has been underestimated. Empirical relationships using liquefaction and surface rupture point to events of at least Ms=6.8 compared to a maximum mb = 5.2 recorded instrumentally. The finding that NE- and NW-trending faults are favourably orientated for reactivation in relation to the current stress field is of potential value for seismic

  18. [Changes of China agricultural climate resources under the background of climate change. VII. Change characteristics of agricultural climate resources in arid and semi-arid region of Tibet Plateau].

    PubMed

    Xu, Hua-jun; Yang, Xiao-guang; Wang, Wen-feng; Xu, Chao

    2011-07-01

    Based on the 1961-2007 ground observation data from 55 meteorological stations in arid and semi-arid region of Tibetan Plateau, and by using 5-day moving average method and ArcGIS-IDW module, this paper analyzed the spatiotemporal change characteristics and climatic trend rates of agricultural climate resources in the region in 1961-1980 (period I) and 1981-2007 (period II). In 1961-2007, the sunshine duration during the growth season of chimonophilous crops in the study region changed less, while that during the growth season of thermophilic crops increased but with little spatial change. Comparing with those in period I, the average value of accumulated temperature in period II showed an increasing trend, and the area with > or = 1500 degrees C x d during the growth season of thermophilic crops increased by 33.9%. The precipitation decreased gradually from southeast to northwest. During the growth season of chimonophilous crops, the precipitation in the southeast in the two periods reached 800 mm, but the climatic trend in other areas was positive or negative, and the change rate was small. The area with precipitation > or = 400 mm during the growth season of thermophilic crops in period II expanded by 40%, as compared in period I. The reference crop evapotranspiration (ET0) generally increased slightly, and shared the similar spatial distribution pattern with sunshine duration and accumulated temperature. During the growth season of thermophilic crops, the area with ET0 > or = 400 mm in period II expanded by 35.7%, compared with that in period I. In the study period, the heat and precipitation resources during crop growth seasons in Tibet Plateau increased in a certain degree, which was very beneficial to the agriculture-stock production. However, the increase of reference crop evapotranspitation indicated the increase of potential evaporation. Thereby, the researches about the possible effects of climate change on agriculture-stock production should be further

  19. Boron in tree-ring as an indicator of forest disturbances in the Lower Athabasca Oil Sands region, Northeastern Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Bégin, Christian; Savard, Martine M.; Marion, Joëlle; Thiffault, Évelyne; Pinno, Brad

    2016-04-01

    Industrial activities related to oil sands (OS) extraction in northeastern Alberta (Canada) have generated, since 1967, important quantities of NOx and SO2 emissions that can lead to several negative effects on forest ecosystems including the potential for soil acidification. In addition, mining processes, tailing pond treatments and heavy transport (haul roads) in mining areas are considered important sources of air contaminants that have the potential to impair forest health by affecting the nutrient balance and physiology of trees. In this study, we analysed micronutrients (B, Fe, Zn, Na, Cu) and macronutrients (Ca, Mg, Mn, K) in the tree-ring series of jack pine (Pinus banksiana) and spruce (Picea glauca and Picea mariana) trees growing at different distances from the heart of mining operations (two sites for each species). Based on tree-ring records, our aims were to provide a historical perspective on the nutritional status of forest ecosystems and to identify temporal changes in tree-ring chemistry that can be attributed to OS activities. One of the key findings of this research is the direct and immediate response of boron (B) in woody tissues of all studied species to mining operations. During the pre-mining period (prior to 1967) [B] variations in tree-rings of the three species covary with other elements such as Na and Fe and are likely controlled by environmental factors, namely climatic conditions. After 1970, [B] increases and strongly departs from trends of other elements. In jack pine trees (54 km NNE of the centre of industrial operations) the increasing trend is abrupt with mean [B] increasing from 11.7 mg/kg during the pre-industrial period to 14.3 mg/kg during mining period. In spruce trees at the proximal site (14 km NE), [B] increases gradually and nicely reproduces the historical pattern of industrial emissions with mean pre-mining [B] of 29.5 mg/kg increasing to 92.1 mg/kg during the mining period. At the four spruce sites, the increasing

  20. A regional field-based assessment of organic C sequestration and GHG balances in irrigated agriculture in Mediterranean semi-arid land

    NASA Astrophysics Data System (ADS)

    Virto, Inigo; Antón, Rodrigo; Arias, Nerea; Orcaray, Luis; Enrique, Alberto; Bescansa, Paloma

    2016-04-01

    In a context of global change and increasing food demand, agriculture faces the challenge of ensuring food security making a sustainable use of resources, especially arable land and water. This implies in many areas a transition towards agricultural systems with increased and stable productivity and a more efficient use of inputs. The introduction of irrigation is, within this framework, a widespread strategy. However, the C cycle and the net GHG emissions can be significantly affected by irrigation. The net effect of this change needs to be quantified at a regional scale. In the region of Navarra (NE Spain) more than 22,300 ha of rainfed agricultural land have been converted to irrigation in the last years, adding to the previous existing irrigated area of 70,000 ha. In this framework the project Life+ Regadiox (LIFE12 ENV/ES/000426, http://life-regadiox.es/) has the objective of evaluating the net GHG balances and atmospheric CO2 fixation rates of different management strategies in irrigated agriculture in the region. The project involved the identification of areas representative of the different pedocllimatic conditions in the region. This required soil and climate characterizations, and the design of a network of agricultural fields representative of the most common dryland and irrigation managements in these areas. This was done from available public datasets on climate and soil, and from soil pits especially sampled for this study. Two areas were then delimited, mostly based on their degree of aridity. Within each of those areas, fields were selected to allow for comparisons at three levels: (i) dryland vs irrigation, (ii) soil and crop management systems for non-permanent crops, and (iii) soil management strategies for permanent crops (namely olive orchards and vineyards). In a second step, the objective of this work was to quantify net SOC variations and GHG balances corresponding to the different managements identified in the previous step. These

  1. Dengue virus serotype 4, northeastern Peru, 2008.

    PubMed

    Forshey, Brett M; Morrison, Amy C; Cruz, Cristhopher; Rocha, Claudio; Vilcarromero, Stalin; Guevara, Carolina; Camacho, Daria E; Alava, Araceli; Madrid, César; Beingolea, Luis; Suarez, Victor; Comach, Guillermo; Kochel, Tadeusz J

    2009-11-01

    In 2008, dengue virus serotype 4 (DENV-4) emerged in northeastern Peru, causing a large outbreak and displacing DENV-3, which had predominated for the previous 6 years. Phylogenetic analysis of 2008 and 2009 isolates support their inclusion into DENV-4 genotype II, forming a lineage distinct from strains that had previously circulated in the region.

  2. Modeling the distribution of the West Nile and Rift Valley Fever vector Culex pipiens in arid and semi-arid regions of the Middle East and North Africa

    PubMed Central

    2014-01-01

    Background The Middle East North Africa (MENA) region is under continuous threat of the re-emergence of West Nile virus (WNV) and Rift Valley Fever virus (RVF), two pathogens transmitted by the vector species Culex pipiens. Predicting areas at high risk for disease transmission requires an accurate model of vector distribution, however, most Cx. pipiens distribution modeling has been confined to temperate, forested habitats. Modeling species distributions across a heterogeneous landscape structure requires a flexible modeling method to capture variation in mosquito response to predictors as well as occurrence data points taken from a sufficient range of habitat types. Methods We used presence-only data from Egypt and Lebanon to model the population distribution of Cx. pipiens across a portion of the MENA that also encompasses Jordan, Syria, and Israel. Models were created with a set of environmental predictors including bioclimatic data, human population density, hydrological data, and vegetation indices, and built using maximum entropy (Maxent) and boosted regression tree (BRT) methods. Models were created with and without the inclusion of human population density. Results Predictions of Maxent and BRT models were strongly correlated in habitats with high probability of occurrence (Pearson’s r = 0.774, r = 0.734), and more moderately correlated when predicting into regions that exceeded the range of the training data (r = 0.666,r = 0.558). All models agreed in predicting high probability of occupancy around major urban areas, along the banks of the Nile, the valleys of Israel, Lebanon, and Jordan, and southwestern Saudi Arabia. The most powerful predictors of Cx. pipiens habitat were human population density (60.6% Maxent models, 34.9% BRT models) and the seasonality of the enhanced vegetation index (EVI) (44.7% Maxent, 16.3% BRT). Maxent models tended to be dominated by a single predictor. Areas of high probability corresponded with sites of

  3. Application of modified export coefficient method on the load estimation of non-point source nitrogen and phosphorus pollution of soil and water loss in semiarid regions.

    PubMed

    Wu, Lei; Gao, Jian-en; Ma, Xiao-yi; Li, Dan

    2015-07-01

    Chinese Loess Plateau is considered as one of the most serious soil loss regions in the world, its annual sediment output accounts for 90 % of the total sediment loads of the Yellow River, and most of the Loess Plateau has a very typical characteristic of "soil and water flow together", and water flow in this area performs with a high sand content. Serious soil loss results in nitrogen and phosphorus loss of soil. Special processes of water and soil in the Loess Plateau lead to the loss mechanisms of water, sediment, nitrogen, and phosphorus are different from each other, which are greatly different from other areas of China. In this study, the modified export coefficient method considering the rainfall erosivity factor was proposed to simulate and evaluate non-point source (NPS) nitrogen and phosphorus loss load caused by soil and water loss in the Yanhe River basin of the hilly and gully area, Loess Plateau. The results indicate that (1) compared with the traditional export coefficient method, annual differences of NPS total nitrogen (TN) and total phosphorus (TP) load after considering the rainfall erosivity factor are obvious; it is more in line with the general law of NPS pollution formation in a watershed, and it can reflect the annual variability of NPS pollution more accurately. (2) Under the traditional and modified conditions, annual changes of NPS TN and TP load in four counties (districts) took on the similar trends from 1999 to 2008; the load emission intensity not only is closely related to rainfall intensity but also to the regional distribution of land use and other pollution sources. (3) The output structure, source composition, and contribution rate of NPS pollution load under the modified method are basically the same with the traditional method. The average output structure of TN from land use and rural life is about 66.5 and 17.1 %, the TP is about 53.8 and 32.7 %; the maximum source composition of TN (59 %) is farmland; the maximum source

  4. Use and management of mimosa species in the Tehuacán-Cuicatlán Valley, a tropical semi-arid region in Mexico (Fabaceae-Mimosoideae).

    PubMed

    Camargo-Ricalde, S L; Dhillion, S S

    2004-12-01

    We report on the use of 15 Mimosa species within the Tehucán-Cuicatlán Valley, south-central Mexico. Seven of these species are endemic to Mexico, and four species and one variety are endemic to the Valley. We reviewed historical, ethnobotanical and floristic manuscripts, and conducted field studies. Several herbaria were consulted, as well as the BADEPLAM data base. Field work in the Valley has been done from 1994 to date. Most of the Mimosa species occur in the arid tropical scrub and the tropical deciduous forest, which are considered the most endangered vegetation types of the Valley. Our findings show that Mimosa species are used as fodder (45%), fuel (31%), living fences (14%) and construction material (7%). Only one species is used as medicine. Mimosa species are "multipurpose" shrubs/trees of the agrosilvopastoral system of this region.

  5. Hydrologic modeling in semi-arid agricultural region: An integrated approach to study water resources in southern San Joaquin Valley, California

    NASA Astrophysics Data System (ADS)

    Roy, Sagarika

    deficit in the region is 135.66 +/- 11.3 mm and the total annual surplus is 291.47 +/- 24.29 mm. Irrigation should apply when this region undergoes a period of moisture deficit in the months of May to July. From September to October are months of soil water recharge; from November to early February is the period of water surplus due to winter rainfall. It was observed that the growers should apply a depth of approximately 79.37 +/- 11.3 mm to replenish the soil moisture storage over the entire field in the growing season of almond orchards.

  6. Water use and physiology of the riparian tree species Eucalyptus victrix in the semi-arid Pilbara region of Western Australia

    NASA Astrophysics Data System (ADS)

    Pfautsch, S.; Keitel, C.; Adams, M. A.; Turnbull, T.

    2009-04-01

    We examined the water use and physiology of trees growing in a riparian community within the seasonally arid Pilbara region of north-western Australia. This region is arid during the winter months, but monsoonal during summer (November to April). Maximum monthly mean temperatures in summer exceed 40 °C and are c. 25 °C during the winter months. The Millstream study site is located on a section of the Fortescue River system along the base of the Chichester Range c. 100km south of Karratha. This system creates a unique landscape in the Pilbara as it forms several large permanent pools. These pools are maintained by springs from an aquifer beneath the alluvial plain. The groundwater from this aquifer is used as a public water supply for towns in the west Pilbara but industrial development and a growing population will place greater demand on this aquifer. Changes to the local hydrology may have dramatic effects on the local plant community, dominated variously by stands of Eucalyptus victrix (Coolibah) and Eucalyptus camaldulensis (River red gum). This study seeks to understand the dependence of the Millstream riparian ecosystem on the height of the aquifer and to characterise the water use and physiology of Eucalyptus victrix. We used a number of techniques to determine the hydraulic and photosynthetic status of the tree canopy, including isotope, sap flow, water-potential and gas exchange measurements. Initial results from this study show: a) Soil water d18O and d2H is strongly enriched towards the surface, which coincides with a strong increase in salinity. The water source accessed by these trees has been identified by d18O and d2H analysis of xylem water. d18O and d2H were additionally analysed in atmospheric and leaf water pools. b) Sap flow in Coolibah trees shows a unique pattern of sharp early morning rise to a plateau maintained throughout the hottest part of the day, followed by a sharp decline in flow late in the afternoon. c) Leaf water potential

  7. Interannual variability of a precipitation gradient along the semi-arid catchment areas for the metropolitan region of Lima- Peru in relation to atmospheric circulation at the mesoscale

    NASA Astrophysics Data System (ADS)

    Otto, Marco; Seidel, Jochen; Trachte, Katja

    2013-04-01

    The main moisture source for precipitation on the western slopes of the Central Andes is located east of the mountain range known as the Amazon basin. However, the Andean mountains, which reach up to 6000 m a.s.l., strongly influence climatic conditions along the Pacific coastline of South America as a climatic barrier for the low-level tropospheric flow and associated moisture transport from the Amazon basin. Additional, large scale subsidence caused by the South Pacific High inhabits convective rainfall at the Pacific coast where large metropolitan areas such as the Peruvian capital Lima are located. Two contrasts in precipitation can be found while crossing the Andean mountains from West to East. On the Pacific coast, at the location of the metropolitan area of Lima, no more than 10 mm mean annual rainfall occurs. In contrast, up to 1000 mm mean annual rainfall occur only 100 km east of Lima within the upper region (4000 m .a.s.l.) of the Western Cordillera. The transition takes place along the western slopes of the Western Cordillera and is characterised by a strong precipitation gradient. Here, catchment areas are located that provide most of the water resources needed to sustain an urban area of approximately 10 million people. This study investigates the interannual variability of the precipitation gradient between 1998 and 2012. The analysis is based on daily precipitation data of 22 rain gauge station, daily rainfall data of the Tropical Rainfall Mission (TRMM 3B42) at 0.25 degrees and reanalysis data at 36 km spatial resolution at the mesoscale. The reanalysis data was produced using the Weather Research and Forecasting Model. Station data was provided by the Peruvian weather service during the project "Sustainable Water and Wastewater Management in Urban Growth Centres Coping with Climate Change - Concepts for Lima Metropolitana (Peru) (LiWa)", which is financed by the German Federal Ministry of Education and Research (BMBF). We are interested in the

  8. Wild flora of mine tailings: perspectives for use in phytoremediation of potentially toxic elements in a semi-arid region in Mexico.

    PubMed

    Sánchez-López, Ariadna S; Del Carmen A González-Chávez, Ma; Carrillo-González, Rogelio; Vangronsveld, Jaco; Díaz-Garduño, Margarita

    2015-01-01

    The aim of this research was to identify wild plant species applicable for remediation of mine tailings in arid soils. Plants growing on two mine tailings were identified and evaluated for their potential use in phytoremediation based on the concentration of potentially toxic elements (PTEs) in roots and shoots, bioconcentration (BCF) and translocation factors (TF). Total, water-soluble and DTPA-extractable concentrations of Pb, Cd, Zn, Cu, Co and Ni in rhizospheric and bulk soil were determined. Twelve species can grow on mine tailings, accumulate PTEs concentrations above the commonly accepted phytotoxicity levels, and are suitable for establishing a vegetation cover on barren mine tailings in the Zimapan region. Pteridium sp. is suitable for Zn and Cd phytostabilization. Aster gymnocephalus is a potential phytoextractor for Zn, Cd, Pb and Cu; Gnaphalium sp. for Cu and Crotalaria pumila for Zn. The species play different roles according to the specific conditions where they are growing at one site behaving as a PTEs accumulator and at another as a stabilizer. For this reason and due to the lack of a unified approach for calculation and interpretation of bioaccumulation factors, only considering BCF and TF may be not practical in all cases.

  9. Seasonal variation in pans in relation to limno-chemistry, size, hydroperiod, and river connectivity in a semi-arid subtropical region

    NASA Astrophysics Data System (ADS)

    Nhiwatiwa, Tamuka; Dalu, Tatenda

    2017-02-01

    Seasonal pans are hydrologically dynamic, with significant changes in water volume and depth in response to high evaporation, infiltration rates and inundation events. Intra-seasonal and inter-seasonal changes in endorheic and floodplain pans in relation to limnology, size, hydroperiod, and river connectivity were studied over two rainfall seasons across 36 pans at the Save Valley Conservancy. In the study region, floodplain pans were identified as pans that had connectivity with the Save River, while the endorheic pans (large and small) were hydrologically isolated basins. Seasonal trends for physico-chemical variables were initial low and gradual increased for both rainfall seasons. Significant inter-seasonal differences for several physico-chemical variables were observed. No significant differences in physico-chemical variables were observed between large and small endorheic pans, with the except for vegetation cover, which was higher in large pans. Floodplain pans differed from the endorheic systems in pH, conductivity, nutrients and suspended solids. Connectivity was found to be insignificant, as connections between these systems were probably too infrequent. Seasonal pans were uniquely distinguished by their morphometric, physico-chemical and hydrological characteristics. Inevitably, they are vulnerable to climate change with the extent of their resilience currently unknown.

  10. Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

    SciTech Connect

    Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

    1983-05-01

    An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 100{sup 0}C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites.

  11. Hydraulic parameters estimation by using an approach based on vertical electrical soundings (VES) in the semi-arid Khanasser valley region, Syria

    NASA Astrophysics Data System (ADS)

    Asfahani, Jamal

    2016-05-01

    A new alternative approach based on using Vertical electrical sounding (VES) technique is proposed for computing the hydraulic conductivity K of an aquifer. The approach takes only the salinity of the groundwater into consideration. VES measurements in the locations, where available water samples exist, are required in such an approach, in order to calibrate and establish empirical relationships between transverse resistance Dar-Zarrouck TR parameter and modified transverse resistance MTR, and between MTR and transmissivity T. Those relationships are thereafter used to extrapolate the transmissivity even in the VES points where no water samples exist. This approach is tested and practiced in the Khanasser valley, Northern Syria, where the hydraulic conductivity of the Quaternary aquifer is computed. An acceptable agreement is found between the hydraulic conductivity values obtained by the proposed approach and those obtained by the pumping test which range between 0.864 and 8.64 m/day (10-5 and 10-4 m/s). The Quaternary aquifer transmissivity of the Khanasser Valley, has been characterized by using this approach and by adapting the MTR parameter. The transmissivity varies between a minimum of 79 m2/day and a maximum of 814 m2/day, with an average of 283 m2/day and a standard deviation of 145 m2/day. The easy and inexpensive approach proposed in this paper can be applied in other semi arid regions.

  12. Remote sensing for mapping soil moisture and drainage potential in semi-arid regions: Applications to the Campidano plain of Sardinia, Italy.

    PubMed

    Filion, Rébecca; Bernier, Monique; Paniconi, Claudio; Chokmani, Karem; Melis, Massimo; Soddu, Antonino; Talazac, Manon; Lafortune, Francois-Xavier

    2016-02-01

    The aim of this study is to investigate the potential of radar (ENVISAT ASAR and RADARSAT-2) and LANDSAT data to generate reliable soil moisture maps to support water management and agricultural practice in Mediterranean regions, particularly during dry seasons. The study is based on extensive field surveys conducted from 2005 to 2009 in the Campidano plain of Sardinia, Italy. A total of 12 small bare soil fields were sampled for moisture, surface roughness, and texture values. From field scale analysis with ENVISAT ASAR (C-band, VV polarized, descending mode, incidence angle from 15.0° to 31.4°), an empirical model for estimating bare soil moisture was established, with a coefficient of determination (R(2)) of 0.85. LANDSAT TM5 images were also used for soil moisture estimation using the TVX slope (temperature/vegetation index), and in this case the best linear relationship had an R(2) of 0.81. A cross-validation on the two empirical models demonstrated the potential of C-band SAR data for estimation of surface moisture, with and R(2) of 0.76 (bias +0.3% and RMSE 7%) for ENVISAT ASAR and 0.54 (bias +1.3% and RMSE 5%) for LANDSAT TM5. The two models developed at plot level were then applied over the Campidano plain and assessed via multitemporal and spatial analyses, in the latter case against soil permeability data from a pedological map of Sardinia. Encouraging estimated soil moisture (ESM) maps were obtained for the SAR-based model, whereas the LANDSAT-based model would require a better field data set for validation, including ground data collected on vegetated fields. ESM maps showed sensitivity to soil drainage qualities or drainage potential, which could be useful in irrigation management and other agricultural applications.

  13. MISR Images Northeastern Botswana

    NASA Technical Reports Server (NTRS)

    2000-01-01

    MISR images of the Ntwetwe and Sua Pans in northeastern Botswana, acquired on August 18, 2000 (Terra orbit 3553). The left image is a color view from the vertical-viewing (nadir) camera. On the right is a composite of red band imagery in which the 45-degree aft camera data are displayed in blue, 45-degree forward as green, and vertical as red. This combination causes wet areas to appear blue because of the glint-like reflection from water and damp surfaces. Clouds are visible in the upper left corner and right center of each image. The clouds look peculiar in the multi-angle view because geometric parallax resulting from their elevation above the surface causes a misregistration of the individual images making up the composite. This stereoscopic effect provides a way of distinguishing clouds from bright surfaces.

    The images are approximately 250 kilometers across. Ntwetwe and Sua pans are closed interior basins that catch rainwater and surface runoff during the wet season. Seasonal lakes form that may reach several meters in depth. During the dry season the collected waters rapidly evaporate leaving behind dissolved salts that coat the surface and turn it bright ('sua' means salt). The mining town of Sowa is located where the Sua Spit (a finger of grassland extending into the pan) attaches to the shore. Sowa represents headquarters for a JPL contingent carrying out MISR field experiments using the evaporite surface and the grasslands as targets and for Botswana scientists studying migration of groundwaters beneath the pans and surrounding areas. These efforts support the Southern Africa Regional Science Initiative (SAFARI-2000), which is now underway.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

    For more information: http://www-misr.jpl.nasa.gov

  14. Carbon fluxes resulting from land-use changes in the Tamaulipan thornscrub of northeastern Mexico

    PubMed Central

    Návar-Chaidez, Jose de Jesus

    2008-01-01

    Information on carbon stock and flux resulting from land-use changes in subtropical, semi-arid ecosystems are important to understand global carbon flux, yet little data is available. In the Tamaulipan thornscrub forests of northeastern Mexico, biomass components of standing vegetation were estimated from 56 quadrats (200 m2 each). Regional land-use changes and present forest cover, as well as estimates of soil organic carbon from chronosequences, were used to predict carbon stocks and fluxes in this ecosystem. For the period of 1980–1996, the Tamaulipan thornscrub is presenting an annual deforestation rate of 2.27% indicating that approximately 600 km2 of this plant community are lost every year and that 60% of the original Mexican Tamaulipan thornscrub vegetation has been lost since the 1950's. On the other hand, intensive agriculture, including introduced grasslands increased (4,000 km2) from 32 to 42% of the total studied area, largely at the expense of the Tamaulipan thornscrub forests. Land-use changes from Tamaulipan thornscrub forest to agriculture contribute 2.2 Tg to current annual carbon emissions and standing biomass averages 0.24 ± 0.06 Tg, root biomass averages 0.17 ± 0.03 Tg, and soil organic carbon averages 1.80 ± 0.27 Tg. Land-use changes from 1950 to 2000 accounted for Carbon emissions of the order of 180.1 Tg. Projected land-use changes will likely contribute to an additional carbon flux of 98.0 Tg by the year 2100. Practices to conserve sequester, and transfer carbon stocks in semi-arid ecosystems are discussed as a means to reduce carbon flux from deforestation practices. PMID:18826617

  15. Carbon fluxes resulting from land-use changes in the Tamaulipan thornscrub of northeastern Mexico.

    PubMed

    Návar-Chaidez, Jose de Jesus

    2008-09-30

    Information on carbon stock and flux resulting from land-use changes in subtropical, semi-arid ecosystems are important to understand global carbon flux, yet little data is available. In the Tamaulipan thornscrub forests of northeastern Mexico, biomass components of standing vegetation were estimated from 56 quadrats (200 m2 each). Regional land-use changes and present forest cover, as well as estimates of soil organic carbon from chronosequences, were used to predict carbon stocks and fluxes in this ecosystem.For the period of 1980-1996, the Tamaulipan thornscrub is presenting an annual deforestation rate of 2.27% indicating that approximately 600 km2 of this plant community are lost every year and that 60% of the original Mexican Tamaulipan thornscrub vegetation has been lost since the 1950's. On the other hand, intensive agriculture, including introduced grasslands increased (4,000 km2) from 32 to 42% of the total studied area, largely at the expense of the Tamaulipan thornscrub forests. Land-use changes from Tamaulipan thornscrub forest to agriculture contribute 2.2 Tg to current annual carbon emissions and standing biomass averages 0.24 +/- 0.06 Tg, root biomass averages 0.17 +/- 0.03 Tg, and soil organic carbon averages 1.80 +/- 0.27 Tg. Land-use changes from 1950 to 2000 accounted for Carbon emissions of the order of 180.1 Tg. Projected land-use changes will likely contribute to an additional carbon flux of 98.0 Tg by the year 2100. Practices to conserve sequester, and transfer carbon stocks in semi-arid ecosystems are discussed as a means to reduce carbon flux from deforestation practices.

  16. Rainfall events and soil moisture deviations as detected by operational ASCAT soil moisture data: case study in semi-arid regions of Somalia

    NASA Astrophysics Data System (ADS)

    Doubkova, M.; Bartsch, A.; Wagner, W.

    2009-04-01

    Large and widely dispersed populations in Somalia depend on pastoralism and on rainfed and irrigated farming. Droughts and floods that have plagued the country in the course of its history were critical for the herders and farmers and have often initiated long-lasting food crises. Recently, the Somalia Water and Land Information Management (SWALIM) has initiated collaborative activities to identify and quantify the physical causes of drought for better understanding of this phenomenon and better addressing the humanitarian aid in Somalia. The soil moisture was identified as one of the parameter that may improve the drought assessment studies in Somalia. The poor accessibility and long-lasting conflicts in Somalia region caused periods of missing values in the meteorological networks that complicate or disable further weather analyses. In this study, a comparison of operational available spatial soil moisture dataset from active microwave sensor with 50 km spatial resolution - ASCAT scatterometer - with existing in-situ rainfall data is performed. The ASCAT data are processed at the Vienna University of Technology (TU WIEN), and recently became operationally available via EUMETCAST. Together with its predecessor - ERS 1/2 - the ASCAT/ERS scatterometers embrace period of 1992 until recent with existing gap over Somalia (2001-2007). The rainfall data were provided by the SWALIM organization. The focus is brought on the ability of the ASCAT scatterometer to detect first rains in the season that dictate the schedule of agricultural activities from land preparation, crop variety to selection to planting. Further, the ability to detect moisture deviations with coarse resolution soil moisture data is studied. The remote sensing data are especially important for countries like Somalia with the poor field accessibility. The improved understanding of the soil moisture data from active microwave sensor may help in interpolating data from existing in-situ networks both

  17. Epidemiology of Meningococcal Disease in Northeastern Africa

    DTIC Science & Technology

    1987-01-01

    meningococcal meningits in Bamako, Mali: epidemiological features and analysis of vaccine efficacy, Lancet, ii, 315, 1982. 17. Kilpatrickt, MW. E., Maill. 1. A...r LIE) DTIC , . [iE LE CTE ili D PUBLICATION REPORT 1514 33/88 EPIDEMIOLOGY OF MENINGOCOCCAL DISEASE IN NORTHEASTERN AFRICA BY John E. Sippel, and...to the southern regions of the Sudan. Like the disease in the sub-Siaharan region, meningococcal meningitis in the Nile Valley is seaso- nal and most

  18. Eolian dust forcing of river chemistry on the northeastern Tibetan Plateau since 8 Ma

    NASA Astrophysics Data System (ADS)

    Yang, Yibo; Galy, Albert; Fang, Xiaomin; Yang, Rongsheng; Zhang, Weilin; Zan, Jinbo

    2017-04-01

    Eolian dust is one of the most important factors controlling fluvial hydrological evolution in modern arid and semi-arid central Asia. Here, we present the bulk carbonate Ca-Mg-Sr concentrations and Sr isotopic compositions recorded in water soluble salts, carbonate and silicate fractions, as well as the Nd isotopic compositions in the silicate fraction of a Late Miocene (12.2-5.1 Ma) fluvial sequence exhibiting paleosol development, in the Linxia Basin on the northeastern Tibetan Plateau (TP). Bulk carbonate Mg-Sr systematics show a distinct pattern in log-log plots of Mg/Ca versus log Sr/Ca ratios, and clearly higher 87Sr/86Sr ratios since ∼8 Ma. These findings cannot be adequately explained by the mechanism of prior calcite precipitation (PCP) - this latter process results in a positive correlation between the Mg/Ca and Sr/Ca ratios in authigenic calcite, evident in the fixed gradient in their log-log plots and has been isolated as being the major factor controlling carbonate Mg-Sr systematics before 8 Ma. Nor can these findings be explained by other mechanisms related to the catchment's provenance/sedimentation. The dramatic changes in carbonate Sr contents, Sr isotopes, and Sr/Mg ratios since ∼8 Ma may therefore be inferred to have been triggered by significant inputs of eolian dust via the dissolution of dust carbonates and evaporites in the paleowaters where fluvial and paleosol carbonates precipitated. This process of eolian dust input can be reliably illustrated using a binary mixing model corresponding to a series of varying PCP fluxes (identical to processes affecting the area before 8 Ma) combined with a constant eolian influx calculated from the co-variations between Mg/Ca, Sr/Ca and Sr isotopic ratios. Eolian dust also leaves a fingerprint in the carbonate and silicate minerals of bulk sediments, as revealed respectively by their Sr and Nd isotopic compositions. Eolian dust compositions for the ∼8-5 Ma on the northeastern TP can thus be taken to

  19. Conservation status of an endangered annual fish Hypsolebias antenori (Rivulidae) from Northeastern Brazil.

    PubMed

    Nascimento, W S; Yamamoto, M E; Chellappa, N T; Rocha, O; Chellappa, S

    2015-05-01

    This work presents information regarding the biology and state of conservation of an endangered annual fish Hypsolebias antenori. Fish were captured from small seasonal pools located in Northeastern Brazil. The total body length, body mass, sex ratio, first sexual maturity were investigated. The sampled population showed sexual dimorphism. There was a predominance of females (60%) over males (40%) with a sex ratio of 1: 1.4 and males were bigger and heavier than the females. Amplitude of total length of males ranged from 2.6 to 7.1cm (4.1 ± 1.15) and that of females from 2.2 to 5.4 cm (3.6 ± 0.9). Amplitude of body mass of males varied from 0.25 to 7 g (1.3 g ± 1.4) and that of females from 0.12 to 2.1g (0.7 g ± 0.5). The total weight-length equation of males was Wt = 0.0108Lt3.172 with r = 0.9826 and of females was Wt = 0.0122Lt3.0114 with r = 0.9608. Females attained first sexual maturity at 3.2 cm (± 0.25) total length and males at 3.3 cm (± 0.08) total length. All temporary pools surveyed in Northeastern Brazil were in a high degree of degradation, suffering due to anthropogenic action. Reduced rainfall resulting from global climate change prevents the filling up of these pools, thus preventing the completion of the reproductive cycle of annual fishes. One factor hindering development of conservation strategies is limited literature on biology and conservation status of annual fishes. There is a need for conservation measures to protect annual fish populations, especially creation of protected areas in the Brazilian semiarid region.

  20. The carbon balance pivot point of southwestern U.S. semiarid ecosystems: Insights from the 21st century drought

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global-scale studies indicate that semiarid regions strongly regulate the terrestrial carbon sink. However, we lack understanding of how climatic shifts, such as decadal drought, impact carbon sequestration across the wide-range of structural diversity in semiarid ecosystems. Therefore, we used edd...

  1. Marine mammal distribution and abundance in an offshore sub-region of the northeastern Chukchi Sea during the open-water season

    NASA Astrophysics Data System (ADS)

    Aerts, Lisanne A. M.; McFarland, Alexandra E.; Watts, Bridget H.; Lomac-MacNair, Kate S.; Seiser, Pamela E.; Wisdom, Sheyna S.; Kirk, Alex V.; Schudel, Carissa A.

    2013-09-01

    This paper describes the distribution and abundance of marine mammals during the open-water season within and near three offshore oil and gas prospects in the northeastern Chukchi Sea, known as the Klondike, Burger, and Statoil study areas. We collected vessel-based marine mammal data during July-October 2008-2010 along line transects oriented in a north-south direction. Over this period, we surveyed ~18,600 km of on-transect effort in the three study areas. Sightings of cetaceans were rare. The bowhead whale was the primary cetacean species sighted and was mostly observed in October (33 of 35 animals). Pinnipeds were the most abundant marine mammals in the study area, with 980 seals and 367 walruses recorded on transect. Most seals were observed as solitary animals, while walruses were often observed in aggregations. We calculated seal and walrus densities using species-specific detection functions corrected for probability of detection. There was high interannual variability in the abundance of seals and walruses that for some species may be related to interannual differences in ice conditions. Notwithstanding this variation, the distribution data suggest that benthic-feeding bearded seals and walruses generally were more common in the Burger and Statoil study areas, which can be characterized as more benthic-dominated ecosystems. The distribution of ringed/spotted seals did not show any statistically significant differences among the study areas, although a slight preference for the Klondike and Statoil study areas was suggested. Both of these study areas are affected by Bering Sea Water from the Central Channel and have a stronger pelagic component than the Burger study area. Continued sampling of these areas will help establish whether the observed trends in marine mammal distribution and abundance are persistent.

  2. Ungulate exclusion, conifer thinning and mule deer forage in northeastern New Mexico

    USGS Publications Warehouse

    Kramer, David W.; Sorensen, Grant E.; Taylor, Chase A.; Cox, Robert D.; Gipson, Philip S.; Cain, James W.

    2015-01-01

    The southwestern United States has experienced expansion of conifer species (Juniperus spp. and Pinus ponderosa) into areas of semi-arid grassland over the past century. The expansion of conifers can limit palatable forage and reduce grass and forb communities. Conifer species are sometimes thinned through hydraulic mulching or selective cutting. We assessed the effects of these treatments on mule deer (Odocoileus hemionus) habitat in northeastern New Mexico to determine if conifer thinning improved cover of preferred forage species for mule deer in areas with and without ungulates. We measured plant cover and occurrence of preferred forage species in the summers of 2011 and 2012. An ongoing regional drought probably reduced vegetation response, with preferred forage species and herbaceous cover responding to conifer thinning or ungulate exclusion immediately following treatment, but not the following year. In 2011, areas that received thinning treatments had a higher abundance of preferred forage when compared to sites with no treatment. Grass coverage exhibited an immediate response in 2011, with ungulate exclosures containing 8% more coverage than areas without exclosures. The results suggest that conifer thinning and ungulate exclusion may elicit a positive response, however in the presence of drought; the positive effects are only short-term.

  3. Latent heat loss of dairy cows in an equatorial semi-arid environment.

    PubMed

    da Silva, Roberto Gomes; Maia, Alex Sandro Campos; de Macedo Costa, Leonardo Lelis; de Queiroz, João Paulo A Fernandes

    2012-09-01

    The present study aimed to evaluate evaporative heat transfer of dairy cows bred in a hot semi-arid environment. Cutaneous (E(S)) and respiratory (E(R)) evaporation were measured (810 observations) in 177 purebred and crossbred Holstein cows from five herds located in the equatorial semi-arid region, and one herd in the subtropical region of Brazil. Rectal temperature (T(R)), hair coat surface temperature (T(S)) and respiratory rate (F(R)) were also measured. Observations were made in the subtropical region from August to December, and in the semi-arid region from April to July. Measurements were done from 1100 to 1600 hours, after cows remained in a pen exposed to the sun. Environmental variables measured in the same locations as the animals were black globe temperature (T(G)), air temperature (T(A)), wind speed (U), and partial air vapour pressure (P(V)). Data were analysed by mixed models, using the least squares method. Results showed that average E(S) and E(R) were higher in the semi-arid region (117.2 W m(-2) and 44.0 W m(-2), respectively) than in the subtropical region (85.2 W m(-2) and 30.2 W m(-2), respectively). Herds and individual cows were significant effects (P < 0.01) for all traits in the semi-arid region. Body parts did not affect T(S) and E(S) in the subtropical region, but was a significant effect (P < 0.01) in the semi-arid region. The average flank T(S) (42.8°C) was higher than that of the neck and hindquarters (39.8°C and 41.6°C, respectively). Average E(S) was higher in the neck (133.3 W m(-2)) than in the flank (116.2 W m(-2)) and hindquarters (98.6 W m(-2)). Coat colour affected significantly both T(S) and E(S) (P < 0.01). Black coats had higher T(S) and E(S) in the semi-arid region (41.7°C and 117.2 W m(-2), respectively) than white coats (37.2°C and 106.7 W m(-2), respectively). Rectal temperatures were almost the same in both subtropical and semi-arid regions. The results highlight the need for improved management methods specific

  4. Use of the subsurface thermal regime as a groundwater-flow tracer in the semi-arid western Nile Delta, Egypt

    NASA Astrophysics Data System (ADS)

    Salem, Zenhom E.; Bayumy, Dina A.

    2016-06-01

    Temperature profiles from 25 boreholes were used to understand the spatial and vertical groundwater flow systems in the Western Nile Delta region of Egypt, as a case study of a semi-arid region. The study area is located between the Nile River and Wadi El Natrun. The recharge areas, which are located in the northeastern and the northwestern parts of the study area, have low subsurface temperatures. The discharge areas, which are located in the western (Wadi El Natrun) and southern (Moghra aquifer) parts of the study area, have higher subsurface temperatures. In the deeper zones, the effects of faults and the recharge area in the northeastern direction disappear at 80 m below sea level. For that depth, one main recharge and one main discharge area are recognized. The recharge area is located to the north in the Quaternary aquifer, and the discharge area is located to the south in the Miocene aquifer. Two-dimensional groundwater-flow and heat-transport models reveal that the sealing faults are the major factor disturbing the regional subsurface thermal regime in the study area. Besides the main recharge and discharge areas, the low permeability of the faults creates local discharge areas in its up-throw side and local recharge areas in its down-throw side. The estimated average linear groundwater velocity in the recharge area is 0.9 mm/day to the eastern direction and 14 mm/day to the northwest. The average linear groundwater discharge velocities range from 0.4 to 0.9 mm/day in the southern part.

  5. Climate warming threatens semi-arid forests in Inner Asia

    NASA Astrophysics Data System (ADS)

    WU, X.

    2015-12-01

    A line of evidences reveal an increasing tree growth decline and tree mortality mainly attributable to climate warming and the warming-mediated changes in drought and other processes in many parts of world tropical, temperate and boreal forests. However, the growth responses to climate change of the widely distributed semi-arid forests are unclear. Here, we synthetically investigate the tree growth patterns during past decades and its interannual response to climate variations in Inner Asia combining the ground truth field survey and samplings, remote sensing observations and climate data. We identified a pervasive tree growth decline since mid-1990s in semi-arid forests in Inner Asia. The widely observed tree growth decline is dominantly attributable to warming-induced water stress during pre- and early growing season. Tree growth of semi-arid forests in Inner Asia is particularly susceptible to spring warming and has been suffering a prolonged growth limitation in recent decades due to spring warming-mediated water conditions. Additionally, we identified a much slower growth rate in younger trees and a lack of tree regeneration in these semi-arid forests. The widely observed forest growth reduction and lack of tree regeneration over semi-arid forests in Inner Asia could predictably exert great effects on forest structure, regionally/globally biophysical and biochemical processes and the feedbacks between biosphere and atmosphere. Notably, further increases in forest stress and tree mortality could be reasonably expected, especially in context of the increase frequency and severity of high temperature and heat waves and changes in forest disturbances, potentially driving the eventual regional loss of current semi-arid forests. Given the potential risks of climate induced forest dieback, increased management attention to adaptation options for enhancing forest resistance and resilience to projected climate stress can be expected. However, the functionally realistic

  6. The Role of Morphotectonics in Gully Formation: Two Case Studies in Semiarid Areas

    NASA Astrophysics Data System (ADS)

    Quénéhervé, Geraldine; Maerker, Michael; Zakerinejad, Reza

    2016-04-01

    Tectonic activities significantly contribute to the formation of the existing drainage systems and hence, to landscape evolution. In this study we assessed the influence of morphotectonics in two semiarid catchments in the Zagros range in Southwestern Iran and in the Makuyuni/ Lake Manyara area in Northern Tanzania. Soil erosion and severe gullying affect large parts of both study catchments. Earthquake activities and associated uplifting, fracturing and faulting are still active in large parts of the Zagros range. Tectonic processes in the East African Rift System have significantly contributed to the formation of the current drainage systems and landforms. This study focuses on the morphotectonics with an analysis of topography, drainage networks, stream longitudinal profiles and lineaments. A specific objective is to study the effects of morphotectonic processes and their effects on gullying. The TecDEM software identifies knickpoints showing abrupt changes in the river profiles, hence indicates tectonic activity in turn changing the drainage network. An investigation of base level and statistical moments of the hypsometric curves provides evidences for the spatial distribution of gully erosion phenomena. The knickpoints act as local erosion base level, and any changes in the knickpoint location leads to a response of erosional processes in the watershed above the knickpoints. Hence gully systems might indicate morphotectonic activities as one of the triggering factors in gully formation. The results of regional tectonic instability suggest that tectonic processes are a significant factor for the current landscape evolution in the two basins. We illustrate that severe gully erosion is strongly related to these tectonic processes, especially in the Southwest of the Mazayjan catchment (Iran) and in the Northeastern and Northern part of the Makuyuni catchment (Tanzania).

  7. Thyroid abnormality trend over time in northeastern regions of Kazakstan, adjacent to the Semipalatinsk nuclear test site: a case review of pathological findings for 7271 patients.

    PubMed

    Zhumadilov, Z; Gusev, B I; Takada, J; Hoshi, M; Kimura, A; Hayakawa, N; Takeichi, N

    2000-03-01

    From 1949 through 1989 nuclear weapons testing carried out by the former Soviet Union at the Semipalatinsk Nuclear Test Site (SNTS) resulted in local fallout affecting the residents of Semipalatinsk, Ust-Kamenogorsk and Pavlodar regions of Kazakstan. To investigate the possible relationship between radiation exposure and thyroid gland abnormalities, we conducted a case review of pathological findings of 7271 urban and rural patients who underwent surgery from 1966-96. Of the 7271 patients, 761 (10.5%) were men, and 6510 (89.5%) were women. The age of the patients varied from 15 to 90 years. Overall, a diagnosis of adenomatous goiter (most frequently multinodular) was found in 1683 patients (63.4%) of Semipalatinsk region, in 2032 patients (68.6%) of Ust-Kamenogorsk region and in 1142 patients (69.0%) of Pavlodar region. In the period 1982-96, as compared before, there was a noticeable increase in the number of cases of Hashimoto's thyroiditis and thyroid cancer. Among histological forms of thyroid cancer, papillary (48.1%) and follicular (33.1%) predominated in the Semipalatinsk region. In later periods (1987-96), an increased frequency of abnormal cases occurred among patients less than 40 years of age, with the highest proportion among patients below 20 in Semipalatinsk and Ust-Kamenogorsk regions of Kazakstan. Given the positive findings of a significant cancer-period interaction, and a significant trend for the proportion of cancer to increase over time, we recommend more detailed and etiologic studies of thyroid disease among populations exposed to radiation fallout from the SNTS in comparison to non-exposed population.

  8. Mucorales from the semiarid of Pernambuco, Brazil

    PubMed Central

    de Azevedo Santiago, André Luiz Cabral Monteiro; dos Santos, Paulo Jorge Parreira; Maia, Leonor Costa

    2013-01-01

    Nineteen taxa of Mucorales, belonging to Absidia, Apophysomyces, Cunninghamella, Fennellomyces, Lichtheimia, Mucor, Mycotypha, Rhizopus and Syncephalastrum were isolated from 36 composite soil samples in three semiarid areas in the State of Pernambuco (Triunfo, Cabrobó and Belém de São Francisco), Northeast Brazil, which are characterized by Caatinga vegetation. Triunfo is preserved, whereas Cabroró and Belém de São Francisco are experiencing low and severe desertification processes, respectively. Mucorales were isolated in Petri dishes in triplicate from 5 mg samples of soil placed on the surface of wheat germ agar plus chloramphenicol and Cercobin [Dimethyl 4,49-(103 phenylene) bis (3-thioallophanate)] medium. The plates were left on a bench at room temperature (28 ± 2 °C) for 72 h of alternating dark and light periods. Absidia cylindrospora presented the highest amount of CFU/g of soil, followed by L. hyalospora, C. phaeospora and C. echinulata var. echinulata. The latter, and R. microsporus var. microsporus, presented the highest frequencies of occurrence. Soils from Triunfo showed higher diversity of Mucorales than the samples from the other areas, although without differing statistically in relation to species richness. The communities of Mucorales from the degraded areas were more similar, while that from the preserved area was quite different. Most of the identified specimens have been commonly isolated from soil in other Brazilian regions, which indicates that they are not endemic of the semiarid. Eleven taxa are registered for the first time in this ecosystem, while F. heterothallicus is reported for the first time in Brazil. PMID:24159320

  9. Toward Improved Hyperspectral Analysis in Semiarid Systems

    NASA Astrophysics Data System (ADS)

    Glenn, N. F.; Mitchell, J.

    2012-12-01

    Idaho State University's Boise Center Aerospace Laboratory (BCAL) has processed and applied hyperspectral data for a variety of biophysical sciences in semiarid systems over the past 10 years. HyMap hyperspectral data have been used in most of these studies, along with AVIRIS, CASI, and PIKA-II data. Our studies began with the detection of individual weed species, such as leafy spurge, corroborated with extensive field analysis, including spectrometer data. Early contributions to the field of hyperspectral analysis included the use of: time-series datasets and classification threshold methods for target detection, and subpixel analysis for characterizing weed invasions and post-fire vegetation and soil conditions. Subsequent studies optimized subpixel unmixing performance using spectral subsetting and vegetation abundance investigations. More recent studies have extended the application of hyperspectral data from individual plant species detection to identification of biochemical constituents. We demonstrated field and airborne hyperspectral Nitrogen absorption in sagebrush using combinations of data reduction and spectral transformation techniques (i.e., continuum removal, derivative analysis, partial least squares regression). In spite of these and many other successful demonstrations, gaps still exist in effective species level discrimination due to the high complexity of soil and nonlinear mixing in semiarid shrubland. BCAL studies are currently focusing on complimenting narrowband vegetation indices with LiDAR (light detection and ranging, both airborne and ground-based) derivatives to improve vegetation cover predictions. Future combinations of LiDAR and hyperspectral data will involve exploring the full range spectral information and serve as an integral step in scaling shrub biomass estimates from plot to landscape and regional scales.

  10. Integrated well log and 2-D seismic data interpretation to image the subsurface stratigraphy and structure in north-eastern Bornu (Chad) basin

    NASA Astrophysics Data System (ADS)

    Isyaku, Aminu A.; Rust, Derek; Teeuw, Richard; Whitworth, Malcolm

    2016-09-01

    Structural and stratigraphic mapping within the Bornu Basin in north east Nigeria was commonly carried out using traditional field geological methods. However, such traditional approaches remain inadequate in the semi-arid region characterised by topographically flat areas and lack of continuous bedrock outcrops that are mostly concealed beneath sand cover. Previous studies in the north-eastern part of the basin carried out using ditch cuttings from few wells and disconnected seismic data were largely inadequate and the resulting stratigraphic analyses were more often generalised. This paper presents an integrated structural and stratigraphic study of the basin using combined subsurface geophysical datasets. A Combined Log Pattern (CLP) method is a well log analysis, which utilises various well log data including gamma ray, resistivity, bulk density and sonic logs to identify lithology and stratigraphic boundaries of subsurface formations. This method is applied to constrain the subsurface stratigraphy of the north-eastern part of the Bornu Basin bordering the Lake Chad. In addition to qualitative combined well log analysis, the time-depth relationship of the sonic log and seismic data was quantitatively determined by tying a well with an intersecting seismic section to validate the stratigraphic facies horizons identified. Four well log facies and their environments of deposition were characterised from the combined well log analysis of the different log types. It is discovered that the Cretaceous basement structural features controlled the deposition of overlying formations in the basin. Without intact core data, the shallower wells were discovered to have bottomed over subsurface horst features while deeper wells penetrated into the basal facies contained mainly within the grabens. Main subsurface structural lineaments in the area include NW-SE, NE-SW and NNW-SSE trending faults, which mainly formed the horst and graben features. Some stratigraphic formations

  11. Early Triassic geologic history of northeastern Nevada

    SciTech Connect

    Paull, R.K.; Paull, R.A.

    1986-08-01

    Conodont biostratigraphic and lithostratigraphic studies of Lower Triassic rocks in northeastern Elko County, Nevada, and adjacent parts of Idaho and Utah provide new information about regional geologic history. A sequential summary of Early Triassic events in this area follows: (1) rapid transgression of the Griesbachian sea to limiting barriers on the south (Oquirrh-Uinta axis) and west (Humboldt highland.). (2) Although the initial Triassic transgression may have persisted farther south and west than present-day evidence indicates, a period of progradation during the Dienerian limited marine sedimentation to northeastern-most Nevada and adjacent states. (3) In Smithian time, a widespread transgression spilled south and west over the earliest Triassic basin margin. (4) The southward flood is characterized by locally spectacular basal conglomerates followed by shallow marine deposits of the Thaynes Formation. (5) The transgression to the west was facilitated by tectonic removal of the restrictive barrier during the Smithian. This resulted in a slope-basin environment that accumulated a thick sequence of shale and calcareous siltstone with interbeds of turbidite conglomerates, olistostromes, and exotic blocks derived from Permian formations in northern Nevada or adjacent Idaho. (6) During a regional progradation in early Spathian time, marine conditions persisted in northeastern Nevada. (7) A final depositional episode is documented by the progressive westward spread of carbonate rocks of the Thaynes Formation. (8) Withdrawal of Triassic seas from northeast Nevada occurred post-latest Early Triassic, since a carbonate sequence of more than 300 m overlies the youngest dated interval.

  12. Holocene sediment distribution on the inner continental shelf of northeastern South Carolina: implications for the regional sediment budget and long-term shoreline response

    USGS Publications Warehouse

    Denny, Jane F.; Schwab, William C.; Baldwin, Wayne E.; Barnhardt, Walter A.; Gayes, Paul T.; Morton, R.A.; Warner, John C.; Driscoll, Neal W.; Voulgaris, George

    2013-01-01

    High-resolution geophysical and sediment sampling surveys were conducted offshore of the Grand Strand, South Carolina to define the shallow geologic framework of the inner shelf. Results are used to identify and map Holocene sediment deposits, infer sediment transport pathways, and discuss implications for the regional coastal sediment budget. The thickest deposits of Holocene sediment observed on the inner shelf form shoal complexes composed of moderately sorted fine sand, which are primarily located offshore of modern tidal inlets. These shoal deposits contain ~67 M m3 of sediment, approximately 96% of Holocene sediment stored on the inner shelf. Due to the lack of any significant modern fluvial input of sand to the region, the Holocene deposits are likely derived from reworking of relict Pleistocene and older inner-shelf deposits during the Holocene marine transgression. The Holocene sediments are concentrated in the southern part of the study area, due to a combination of ancestral drainage patterns, a regional shift in sediment supply from the northeast to the southwest in the late Pleistocene, and proximity to modern inlet systems. Where sediment is limited, only small, low relief ridges have formed and Pleistocene and older deposits are exposed on the seafloor. The low-relief ridges are likely the result of a thin, mobile veneer of sediment being transported across an irregular, erosional surface formed during the last transgression. Sediment textural trends and seafloor morphology indicate a long-term net transport of sediment to the southwest. This is supported by oceanographic studies that suggest the long-term sediment transport direction is controlled by the frequency and intensity of storms that pass through the region, where low pressure systems yield net along-shore flow to the southwest and a weak onshore component. Current sediment budget estimates for the Grand Strand yield a deficit for the region. Volume calculations of Holocene deposits on the

  13. Buffalo gourd: potential as a fuel resource on semi-arid lands

    SciTech Connect

    Young, P.G.; Morgan, R.P.; Shultz, E.B. Jr.

    1982-01-01

    Buffalo gourd, (Cucurbita foetidissima), is a wild, hot-dry-land plant native to the semi-arid regions of North America. Its triglyceride oil and fermentable starch make it a potential biomass energy source. These products, along with the seed meal and foliage, also offer the potential for cultivation in semi-arid regions of the developing world as a food and feed source. Alternatively, the plant may help to maintain economic vitality in regions such as the Texas High Plains, where declining water supplies threaten present irrigation practices. Technical feasibility, impacts, commercialization requirements, and research needs are discussed.

  14. A Review of the Genus Oecetis (Trichoptera: Leptoceridae) in the Northeastern Region of Brazil with the Description of 5 New Species

    PubMed Central

    Quinteiro, Fabio Batagini; Calor, Adolfo Ricardo

    2015-01-01

    Within Leptoceridae, the genus Oecetis contains about 500 species around the world, including 53 in the Neotropics. In Brazil, there are 15 recorded species of Oecetis. These species were described over several decades by numerous authors with the results that descriptions are not comparable and diagnoses are incomplete. Also, the apparently unbranched M vein, in the forewing, a diagnostic character for Oecetis pointed by McLachlan, is controversial and no consensus has been reached about its homology. Additionally, the only revision for the genus was never published; thus the information and proposed taxa are not available according to the International Code of Zoological Nomenclature. We analyzed specimens collected in the Brazilian Northeast Region and compared these with described species and literature descriptions and Oecetis from other regions. We provide herein the description of five new species, additional characters for diagnosing seven of the species recorded from Brazil, new distributional records, and a dichotomous key to the Brazilian species. Additionally, we contrast the two hypotheses of forewing M vein homology and support the unbranched hypothesis. In this way, we improve the knowledge of the genus in the Neotropics, making the species descriptions comparable in a way that facilitates species identification. PMID:26061538

  15. Diversity, natural history, and geographic distribution of snakes in the Caatinga, Northeastern Brazil.

    PubMed

    Guedes, Thaís B; Nogueira, Cristiano; Marques, Otavio A V

    2014-09-19

    The present study is a synthesis on snake diversity and distribution in the Caatinga region of northeastern Brazil, providing an updated species list and data on natural history and geographic distribution. Our study is based on the careful revision of 7,102 voucher specimens, housed in 17 herpetological collections, complemented by data on taxonomic literature. We recorded a total of 112 snake species in the Caatinga, belonging to nine families: Anomalepididae, Leptotyphlopidae, Typhlopidae, Aniliidae, Boidae, Viperidae, Elapidae, Colubridae, and Dipsadidae. Our list includes at least 13 never recorded species for this region, as well as distribution records for all species known from the Caatinga (including expansion and new records of distribution). The snake assemblage of the Caatinga is complex, sharing species with other continental open areas (38.4%), forested areas (27.7%), and both open and forested areas (32.1%). The richest areas were isolated plateaus, followed by contact areas, semi-arid caatinga, and sandy dunes of the São Franscisco River. We identified 22 Caatinga endemic species with the sandy dunes of São Franscico River showing the highest endemism level (12 species, with six endemic species restricted to the area) followed by semi-arid caatinga, and isolated plateaus (eight endemic species each, and six and three endemic species with restricted distribution to each area, respectively). Most species show relatively restricted ranges in parts of the Caatinga. The snake assemblage in Caatinga includes mainly terrestrial species (38.4%), followed by fossorial/cryptozoic (26.8%), arboreal/semi-arboreal (26.8%), and aquatic/semi-aquatic (7.1%) species. Vertebrates are the most important dietary item (80.4%), with 56.6% of species being generalist consumers of this kind of prey; 24.4% are frog-eaters, 7.8% prey on caecilians/amphisbaenians, 6.7% lizard-eaters, 3.3% mammal-eaters, and 1.1% are fish-eaters. Only 18.7% of the snakes eat invertebrate

  16. Inter-annual variability of air mass and acidified pollutants transboundary exchange in the north-eastern part of the EANET region

    NASA Astrophysics Data System (ADS)

    Gromov, Sergey A.; Trifonova-Yakovleva, Alisa; Gromov, Sergey S.

    2016-04-01

    Anthropogenic emissions, be it exhaust gases or aerosols, stem from multitude of sources and may survive long-range transport within the air masses they were emitted into. So they follow regional and global transport pathways varying under different climatological regimes. Transboundary transfer of pollutants occurs this way and has a significant impact on the ecological situation of the territories neighbouring those of emission sources, as found in a few earlier studies examining the environmental monitoring data [1]. In this study, we employ a relatively facile though robust technique for estimating the transboundary air and concomitant pollutant fluxes using actual or climatological meteorological and air pollution monitoring data. Practically, we assume pollutant transfer being proportional to the horizontal transport of air enclosed in the lower troposphere and to the concentration of the pollutant of interest. The horizontal transport, in turn, is estimated using the mean layer wind direction and strength, or their descriptive statistics at the individual transects of the boundary of interest. The domain of our interest is the segment of Russian continental border in East Asia spanning from 88° E (southern Middle Siberia) to 135° E (Far East at Pacific shore). The data on atmospheric pollutants concentration are available from the Russian monitoring sites of the region-wide Acid Deposition Monitoring Network in East Asia (EANET, http://www.eanet.asia/) Mondy (Baikal area) and Primorskaya (near Vladivostok). The data comprises multi-year continuous measurement of gas-phase and particulate species abundances in air with at least biweekly sampling rate starting from 2000. In the first phase of our study, we used climatological dataset on winds derived from the aerological soundings at Russian stations along the continental border for the 10-year period (1961-1970) by the Research Institute of Hydrometeorological Information - World Data Centre (RIHMI-WDC) [3

  17. A comparison among root soil-conservation effects for nine herbs at the cold region highway in north-eastern China

    NASA Astrophysics Data System (ADS)

    Xu, W.; Wang, X.; Zhang, Y.; Liu, Y.

    2014-12-01

    High soil-conservation herbs are very important for slope vegetation restoration of a highway in serious sandstorm regions. In this study, nine common herbs in northeast China were selected and compared to study soil-conservation effects by using an undisturbed-soil trough scouring method for soil anti-scourability enhancement and hydrostatic collapse method for soil anti-erodibility. Further, principal components analysis was used to identify significant root features that affected soil erosion resistance. Results indicated that different herbs had distinct enhancement effects on soil erosion resistance. Soil anti-scourability enhancement index decreased with increases of soil depth, slope gradient and rainfall amount. Relationship between soil anti-erodibility enhancement index ( S) and immersion time ( t) is a cubic spline in each different herb type ( R 2 ≥ 0.88). Herb root features such as micro-aggregates, organic matter, net leaf weight, thick root length, fine root length and biomass contributed a leading role in soil erosion resistance enhancement effect, and all their common factor variances were more than 0.81. Descending order of soil erosion resistance enhancement effect in soil anti-scourability for nine herbs is Poa pratensis, Medicago sativa, Viola philippica, Rudbeckia hirta, Clematis heracleifolia, Kalimeris indica, Cosmos bipinnata, Hemerocallis fulva and Sedum elatinoides, while the sequence of soil anti-erodibility is M. sativa, S. elatinoides, P. pratensis, R. hirta, H. fulva, V. philippica, C. heracleifolia, C. bipinnata and K. indica. Therefore, we concluded that P. pratensis and M. sativa were the most suitable herbs for resisting soil erosion and recommended to be widely planted for road vegetation recovery in this region.

  18. Pleistocene phylogeography and cryptic diversity of a tiger beetle, Calomera littoralis, in North-Eastern Mediterranean and Pontic regions inferred from mitochondrial COI gene sequences

    PubMed Central

    Rewicz, Tomasz; Płóciennik, Mateusz; Grabowski, Michał

    2016-01-01

    Background. Calomera littoralis is a Palearctic species, widely distributed in Europe; inhabiting predominantly its Atlantic, Mediterranean and Black Sea coastlines. Methods. Its phylogeography on the Balkan Peninsula and on the north-western Black Sea coast was inferred using a 697 bp long portion of the mitochondrial COI gene, amplified from 169 individuals collected on 43 localities. Results. The results revealed two genetically divergent groups/lineages, the southern one inhabiting both the Balkan Peninsula and the Pontic Region and the northern one found exclusively in the Pontic Region. Species delimitation based on DNA barcoding gap suggested an interspecific level of divergence between these groups. Multivariate analysis of eight male and female morphometric traits detected no difference between the groups, implying they may represent cryptic species. The Bayesian time-calibrated reconstruction of phylogeny suggested that the lineages diverged ca. 2.3 Ma, in early Pleistocene. Discussion. The presence of the two genetically divergent groups results most likely from contemporary isolation of the Pontic basin from the Mediterranean that broke the continuous strip of coastal habitats inhabited by C. littoralis. Demographic analyses indicated that both lineages have been in demographic and spatial expansion since ca. 0.15 Ma. It coincides with the terminal stage of MIS-6, i.e., Wartanian/Saalian glaciation, and beginning of MIS-5e, i.e., Eemian interglacial, during which, due to eustatic sea level rise, a wide connection between Mediterranean and the Pontic basin was re-established. This, along with re-appearance of coastal habitats could initiate north-east expansion of the southern lineage and its secondary contact with the northern one. The isolation of the Pontic basin from the Mediterranean during the Weichselian glaciation most likely did not have any effect on their phylogeography. PMID:27547517

  19. Discriminating Between Tectonic and Climatic Controls on Early Hominin Paleoenvironments From the Koobi Fora Region, Northeastern Turkana Basin, Kenya: Part I

    NASA Astrophysics Data System (ADS)

    Lepre, C. J.; Quinn, R. L.

    2004-12-01

    , characterized by uplift in Ethiopia and associated down-warping of the Turkana Basin in Kenya. While the formation of ephemeral-lacustrine and fluvial environments of deposition during the transgressive and highstand systems tract was due to sedimentation rates out-pacing subsidence rates that was associated with the infilling of the stable lake by deltaic environments. Infilling and depletion of accommodation space were primary steps needed to increase the sensitivity of the basin to climate change. Relatively shallow East African sedimentary basins are more sensitive to climate-related changes in evapo-transpiration than relatively deeper basins (e.g. Feibel, 1999). Transgressive and regressive lake margin facies that are associated with the transgressive systems tract suggest that the base level of the ephemeral-lacustrine system periodically oscillated during 2.0 and 1.5 Ma (Feibel, 1994b). The hominin record of Koobi Fora preserves relatively primitive forms between 4.0 and 2.5 Ma and relatively derived forms after about 2.5 Ma (cf. Walker, 2002). Australopithecines are associated with paleoenvironmental change that was forced by linear subsidence rates. The appearance of paranthropines in the region at about 2.5 Ma (cf. Wood, 1991) is associated with an episode of major faulting and paleoenvironmental change that was forced by an exponential decrease in subsidence rates. The appearance of early African Homo erectus in the Koobi Fora Region at 1.8 Ma (e.g. Wood, 1992; Collard and Wood, 1999) coincides with decreased subsidence rates but an increase in the sensitivity of paleoenvironmental organization in the region to climate change.

  20. Drought Analysis in Northeastern Argentine

    NASA Astrophysics Data System (ADS)

    Garcia, N. O.

    2005-12-01

    The objetive of the present work was analyze the occurrence of droughts in the context of the climatic variability, in a wide region of the Argentinean territory that encompass the six provinces of the northeastern (Misiones, Corrientes, Entre Rios, Santa Fe, Chaco and Formosa). In order to define the droughts a decilic analysis of the monthly precipitation records was used, and the temporal and spatial variability were analyzed with Spectral Analysis of the composite dry year (From January of the year of droughts onset until December of the following year), this period contain the complete hydrologic dry-year. It was observed that the occurrence of annual droughts change along the last century, verifying an average of one drought each three years up to 1969 and one drought each five year from 1970. From the point of view of the relative amount of fallen water, it was observed that the extreme dry periods take place in autumn, winter and spring and weak dry period during the summer or to along the complete hydrologic year. The spatial and temporal behavior of the dry periods showed that the composite dry-years are more significant in amplitude and phase than composite LA NIÑA years. So much the rains of summer like the winters droughts accentuate the second harmonic amplitude, that contains information of the amount of fallen water and also represent the annual cycle of the precipitations, while the droughts of summer attenuate it. The harmonic dials in the analyzed region showed that the second spectral component is the most significant, while the first component indicates their relationship with the region EL NIÑO, in the Equatorial Pacific Ocean. The results indicate a regional homogeneous characterization regarding the first harmonic in the north, the same as the area center-eastern, while the southwest and south area has a behavior with characteristic very particular characteristics during the dry events (second harmonic not significant).

  1. Behavioral patterns, parity rate and natural infection analysis in anopheline species involved in the transmission of malaria in the northeastern Brazilian Amazon region.

    PubMed

    Barbosa, Ledayane Mayana Costa; Souto, Raimundo Nonato Picanço; Dos Anjos Ferreira, Ricardo Marcelo; Scarpassa, Vera Margarete

    2016-12-01

    The characterization of behavioral patterns allows a better understanding of the transmission dynamics and the design of more effective malaria vector control strategies. This study analyzed the behavioral patterns of the Anopheles species of the Coração district situated in the northeast of the Brazilian Amazon region. The behavioral patterns of the anopheline species were measured based on the 36 collection sites of this district from December 2010 to November 2011. Collections of four hours for three consecutive nights each month and four 12-h collections, comprising two in the rainy season and two in the dry season, were performed. Furthermore, to infer the anthropophily and zoophily indexes, four additional four-hour collections were performed. The samples were also evaluated for parity rate and natural infectivity for Plasmodium spp. A total of 1689 anophelines were captured, comprising of nine species and two subgenera (Nyssorhynchus - six species, and Anopheles - three species). Anopheles darlingi was the most abundant and widely distributed species in the area, followed by A. braziliensis and A.marajoara. Anopheles darlingi and A. marajoara were the only species present in the four collections of 12-h, but only A. darlingi showed activity throughout night. Anopheles darlingi was the most anthropophilic species (AI=0.40), but the zoophily index was higher (ZI=0.60), revealing an eclectic and opportunistic behavior. Of the six most frequent species, A. nuneztovari s.l. was the most zoophilic species (ZI=1.00). All captured species showed predominance towards biting in outdoor environments. Anopheles darlingi and A. braziliensis showed multimodal biting peaks, whereas A. marajoara revealed a stable pattern, with the biting peak after sunset. Using the PCR technique, no anopheline was found infected with the malaria parasite. Since A. darlingi and A. marajoara are recognized as important vectors in this region, the district of Coração may be considered as

  2. Canola integration into semi-arid wheat cropping systems of the inland Pacific Northwestern USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The inland Pacific Northwestern USA (iPNW) wheat-producing region has a diversity of environments and soils, yet it lacks crop diversity and is one of the few semi-arid wheat-growing regions without significant integration of oilseeds. Four major agroecological zones, primarily characterised by wate...

  3. Freshwater fish's spatial patterns in isolated water springs in North-eastern Mexico.

    PubMed

    Palacio-Núñez, Jorge; Verdú, José R; Numa, Catherine; Jiménez-García, Daniel; Olmos Oropeza, Genaro; Galante, Eduardo

    2010-03-01

    The Media Luna lake-spring was selected as representative of all thermal or no thermal springs in the zone of Valley of Rioverde, a semi-arid vegetation in the North-eastern of Mexico. This system is inhabited by 11 fish species, of which six are native. Four of the native species are endemic to the region and threatened due to touristic pressure and to the introduction of exotic species. The objectives were to determine the characteristics that influence the spatial distribution of the fish species, to analyze their spatial distribution patterns, and to describe the relationships between the different species. The general aim was to establish some basis for the conservation of these fish communities and their habitat. Several sessions were initiated in 1992 through direct observation. Later, between 1998 and 1999 five systematically seasonal sampling sessions were conducted (54 subaquatic transects/session). Finally, the data was updated by sampling in summer 2002 and winter 2006. Through the analysis was performed only for endemics of the region, like Ataeniobius toweri Meek, Cualac tessellatus Miller, Cichlasoma bartoni Bean and C. labridens Pellegrin, in at least one life stage, showed correlation with habitat variables or with other species. For these species, patterns of spatial aggregation and association with other species were observed. These results show a certain degree of specialization of endemic species to some microhabitat characteristics, as well as a significant interaction with other native species which they coexist. In addition, some significant relations between endemic and alien species suggest an antagonist relation. Management actions focused in the touristic use of the spring represent the main threat for these species, followed by an adequate management of exotic species. This study provides basis for future responsible management of these wetlands, where tourism and conservation can be combined.

  4. Isotopic evidence for the dependence of recurrent felsic magmatism on new crust formation: An example from the Georgetown region of Northeastern Australia

    NASA Astrophysics Data System (ADS)

    Black, L. P.; McCulloch, M. T.

    1990-01-01

    material does not necessarily melt and mobilise the preceeding underplate. Often it is a still earlier underplate that is activated. These regions of the lower crust can remain dormant for well over a billion years before they produce widespread magmatism destined for the upper crust.

  5. The Evolution of Total Phenolic Compounds and Antioxidant Activities during Ripening of Grapes (Vitis vinifera L., cv. Tempranillo) Grown in Semiarid Region: Effects of Cluster Thinning and Water Deficit

    PubMed Central

    Garrido, Inmaculada; Uriarte, David; Hernández, Marcos; Llerena, José Luis; Valdés, María Esperanza; Espinosa, Francisco

    2016-01-01

    A study was made of how water status (rainfed vs. irrigated) and crop load (no cluster thinning vs. cluster thinning) can together affect the grapes of Vitis vinifera cv. Tempranillo vines growing in a semiarid zone of Extremadura (Spain). The grapes were monitored at different stages of ripening, measuring the peroxidase (POX) and superoxide dismutase (SOD) antioxidant activities and the phenolic content (flavonoids and phenylpropanoids), together with other parameters. The irrigation regime was adjusted to provide 100% of crop evapotranspiration (ETc). The findings confirmed previous results that both thinning and water deficit advance ripening, while irrigation and high crop load (no thinning) lengthen the growth cycle. The SOD activity remained practically constant throughout ripening in the thinned treatments and was always lower than in the unthinned treatments, an aspect which could have been the cause of the observed greater level of lipid peroxidation in the water deficit, thinned treatment. The nonspecific peroxidase activity was very low, especially in the thinned treatments. The effect of thinning was enhanced when combined with water deficit, inducing increases in phenylpropanoids and, above all, flavonoids at the harvest stage of ripening, while leaving the polyphenol oxidase activity (PPO) unaffected. PMID:27869671

  6. The Evolution of Total Phenolic Compounds and Antioxidant Activities during Ripening of Grapes (Vitis vinifera L., cv. Tempranillo) Grown in Semiarid Region: Effects of Cluster Thinning and Water Deficit.

    PubMed

    Garrido, Inmaculada; Uriarte, David; Hernández, Marcos; Llerena, José Luis; Valdés, María Esperanza; Espinosa, Francisco

    2016-11-17

    A study was made of how water status (rainfed vs. irrigated) and crop load (no cluster thinning vs. cluster thinning) can together affect the grapes of Vitis vinifera cv. Tempranillo vines growing in a semiarid zone of Extremadura (Spain). The grapes were monitored at different stages of ripening, measuring the peroxidase (POX) and superoxide dismutase (SOD) antioxidant activities and the phenolic content (flavonoids and phenylpropanoids), together with other parameters. The irrigation regime was adjusted to provide 100% of crop evapotranspiration (ETc). The findings confirmed previous results that both thinning and water deficit advance ripening, while irrigation and high crop load (no thinning) lengthen the growth cycle. The SOD activity remained practically constant throughout ripening in the thinned treatments and was always lower than in the unthinned treatments, an aspect which could have been the cause of the observed greater level of lipid peroxidation in the water deficit, thinned treatment. The nonspecific peroxidase activity was very low, especially in the thinned treatments. The effect of thinning was enhanced when combined with water deficit, inducing increases in phenylpropanoids and, above all, flavonoids at the harvest stage of ripening, while leaving the polyphenol oxidase activity (PPO) unaffected.

  7. Use of vegetation index and surface temperature to estimate soil moisture in a semi-arid catchment in Brazil with limited monitoring

    NASA Astrophysics Data System (ADS)

    Rebello, V. P. A.; Cunha, T. M.; Rotunno Filho, O. C.; Barbosa, M. C.; Franklin, M. R.; Lakshmi, V.

    2014-12-01

    During the last two decades, there have been numerous studies using remote sensing to study catchment energy and water balance. A well-known example is the combination of surface temperature (Ts) and the normalized difference vegetation index (NDVI), which can provide information on vegetation and moisture conditions at the land surface. Since the soil moisture is a key variable in hydrological modeling, this information is potentially useful in large watersheds and remote areas in developing countries, where little infrastructure and few resources still make continuous in-situ monitoring of environmental variables a difficult task, as well as in semi arid areas, where the lack of water may represent an obstacle to the regional economic and sustainable development. The basic methodology is to calculate soil moisture indexes by the scatter plots of NDVI and Ts and to analyze the Ts/NDVI slope, in order to estimate temporal patterns of soil moisture. We will utilize the standard vegetation index and surface temperature products from MODIS and NOAA - AVHRR, and the results will be compared with soil moisture derived from a hydrological model (Soil Moisture Accounting Procedure). This work will focus on a 18200 km² semi-arid catchment in Northeastern Brazil.

  8. Global climate change, land management, and biosolids application to semiarid grasslands

    SciTech Connect

    Loftin, S.R.

    1995-12-31

    Global climate change combined with improper land management, including over-grazing, can lead to a severe reduction in plant cover and soil productivity. This process is especially common in arid and semiarid regions with sparse vegetation cover. New and innovative methods of land management are needed to restore and maintain these ecosystems in a productive and sustainable state. Research conducted in New Mexico on the Rio Puerco Resource Area and the Sevilleta National Wildlife Refuge has shown that biosolids (municipal sewage sludge) application to semiarid grasslands can increase soil nutrient availability, increase plant cover and productivity, and decrease surface runoff and soil erosion without harming environmental quality.

  9. Impacts of Urbanization on Groundwater Quality and Recharge in a Semi-arid Alluvial Basin

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The management of groundwater resources is paramount in semi-arid regions experiencing urban development. In the southwestern United States, enhancing recharge of urban storm runoff has been identified as a strategy for augmenting groundwater resources. An understanding of how urbanization may impac...

  10. Surface water and shallow groundwater interactions in semiarid agro-ecosystems of western USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface water and groundwater interactions in agro-ecosystems of semiarid regions can translate into multiple hydrological benefits including aquifer recharge, temporary storage, and delayed return flow. Our ongoing research effort aimed to better understand surface water and shallow groundwater int...

  11. A TEN-YEAR WATER BALANCE OF A MOUNTAINOUS SEMI-ARID WATERSHED. (R824784)

    EPA Science Inventory

    Quantifying water balance components, which is particularly challenging in snow-fed, semi-arid regions, is crucial to understanding the basic hydrology of a watershed. In this study, a water balance was computed using 10 years of data collected at the Upper Sheep Creek Water...

  12. A spectral index to monitor the head-emergence of wheat in semi-arid conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Harvesting wheat (Triticium aestivum L.) for forage or leaving it for grain is the main decision uncertainty growers face in semi-arid regions during mid-season. To facilitate decision-making, a decision support system (DSS) has recently been proposed that requires information about crop water and n...

  13. Aggregate Carbon Pools after 13 Years of Integrated Crop-Livestock Management in Semiarid Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Semi-arid regions have the potential to sequester soil organic carbon (SOC) but the magnitude and rate of sequestration is highly management specific. Integrated crop-livestock (ICL) systems that utilize perennial or high-residue no-till annual forage crops as part of the overall agronomic system ma...

  14. Intensifying a semi-arid dryland crop rotation by replacing fallow with pea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing dryland cropping system intensity in the semi-arid central Great Plains by reducing frequency of fallow can add diversity to cropping systems and decrease erosion potential. However elimination of the periodic fallow phase has been shown to reduce yields of subsequent crops in this region...

  15. Using NDVI to measure precipitation in semi-arid landscapes

    USGS Publications Warehouse

    Birtwhistle, Amy N.; Laituri, Melinda; Bledsoe, Brian; Friedman, Jonathan M.

    2016-01-01

    Measuring precipitation in semi-arid landscapes is important for understanding the processes related to rainfall and run-off; however, measuring precipitation accurately can often be challenging especially within remote regions where precipitation instruments are scarce. Typically, rain-gauges are sparsely distributed and research comparing rain-gauge and RADAR precipitation estimates reveal that RADAR data are often misleading, especially for monsoon season convective storms. This study investigates an alternative way to map the spatial and temporal variation of precipitation inputs along ephemeral stream channels using Normalized Difference Vegetation Index (NDVI) derived from Landsat Thematic Mapper imagery. NDVI values from 26 years of pre- and post-monsoon season Landsat imagery were derived across Yuma Proving Ground (YPG), a region covering 3,367 km2 of semiarid landscapes in southwestern Arizona, USA. The change in NDVI from a pre-to post-monsoon season image along ephemeral stream channels explained 73% of the variance in annual monsoonal precipitation totals from a nearby rain-gauge. In addition, large seasonal changes in NDVI along channels were useful in determining when and where flow events have occurred.

  16. Northeastern Summer Electricity Market Alert

    EIA Publications

    2013-01-01

    The National Weather Service declared an excessive-heat warning for much of the Mid-Atlantic and northeastern United States, including major electric markets covering Philadelphia, Boston, Washington, D.C., and New York City. This report highlights the wholesale electricity market activity occurring in response to the higher-than-normal electricity demand caused by the heat wave.

  17. 78 FR 65701 - Notice of Availability of the Nevada and Northeastern California Greater Sage-Grouse Draft Land...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ...] Notice of Availability of the Nevada and Northeastern California Greater Sage-Grouse Draft Land Use Plan... Greater Sage-Grouse Draft Land Use Plan (LUP) Amendments and Draft Environmental Impact Statement (EIS... Northeastern California Sub-region Greater Sage-Grouse Draft LUP Amendments/Draft EIS by any of the...

  18. Quantifying macropore recharge: Examples from a semi-arid area

    USGS Publications Warehouse

    Wood, W.W.; Rainwater, K.A.; Thompson, D.B.

    1997-01-01

    The purpose of this paper is to illustrate the significantly increased resolution of determining macropore recharge by combining physical, chemical, and isotopic methods of analysis. Techniques for quantifying macropore recharge were developed for both small-scale (1 to 10 km2) and regional-scale areas in and semi-arid areas. The Southern High Plains region of Texas and New Mexico was used as a representative field site to test these methods. Macropore recharge in small-scale areas is considered to be the difference between total recharge through floors of topographically dosed basins and interstitial recharge through the same area. On the regional scale, macropore recharge was considered to be the difference between regional average annual recharge and interstitial recharge measured in the unsaturated zone. Stable isotopic composition of ground water and precipitation was used us an independent estimate of macropore recharge on the regional scale. Results of this analysis suggest that in the Southern High Plains recharge flux through macropores is between 60 and 80 percent of the total 11 mm/y. Between 15 and 35 percent of the recharge occurs by interstitial recharge through the basin floors. Approximately 5 percent of the total recharge occurs as either interstitial or matrix recharge between the basin floors, representing approximately 95 percent of the area. The approach is applicable to other arid and semi-arid areas that focus rainfall into depressions or valleys.The purpose of this paper is to illustrate the significantly increased resolution of determining macropore recharge by combining physical, chemical, and isotopic methods of analysis. Techniques for quantifying macropore recharge were developed for both small-scale (1 to 10 km2) and regional-scale areas in arid and semi-arid areas. The Southern High Plains region of Texas and New Mexico was used as a representative field site to test these methods. Macropore recharge in small-scale areas is considered

  19. Preface paper to the Semi-Arid Land-Surface-Atmosphere (SALSA) Program special issue

    USGS Publications Warehouse

    Goodrich, D.C.; Chehbouni, A.; Goff, B.; MacNish, B.; Maddock, T.; Moran, S.; Shuttleworth, W.J.; Williams, D.G.; Watts, C.; Hipps, L.H.; Cooper, D.I.; Schieldge, J.; Kerr, Y.H.; Arias, H.; Kirkland, M.; Carlos, R.; Cayrol, P.; Kepner, W.; Jones, B.; Avissar, R.; Begue, A.; Bonnefond, J.-M.; Boulet, G.; Branan, B.; Brunel, J.P.; Chen, L.C.; Clarke, T.; Davis, M.R.; DeBruin, H.; Dedieu, G.; Elguero, E.; Eichinger, W.E.; Everitt, J.; Garatuza-Payan, J.; Gempko, V.L.; Gupta, H.; Harlow, C.; Hartogensis, O.; Helfert, M.; Holifield, C.; Hymer, D.; Kahle, A.; Keefer, T.; Krishnamoorthy, S.; Lhomme, J.-P.; Lagouarde, J.-P.; Lo, Seen D.; Luquet, D.; Marsett, R.; Monteny, B.; Ni, W.; Nouvellon, Y.; Pinker, R.; Peters, C.; Pool, D.; Qi, J.; Rambal, S.; Rodriguez, J.; Santiago, F.; Sano, E.; Schaeffer, S.M.; Schulte, M.; Scott, R.; Shao, X.; Snyder, K.A.; Sorooshian, S.; Unkrich, C.L.; Whitaker, M.; Yucel, I.

    2000-01-01

    The Semi-Arid Land-Surface-Atmosphere Program (SALSA) is a multi-agency, multi-national research effort that seeks to evaluate the consequences of natural and human-induced environmental change in semi-arid regions. The ultimate goal of SALSA is to advance scientific understanding of the semi-arid portion of the hydrosphere-biosphere interface in order to provide reliable information for environmental decision making. SALSA approaches this goal through a program of long-term, integrated observations, process research, modeling, assessment, and information management that is sustained by cooperation among scientists and information users. In this preface to the SALSA special issue, general program background information and the critical nature of semi-arid regions is presented. A brief description of the Upper San Pedro River Basin, the initial location for focused SALSA research follows. Several overarching research objectives under which much of the interdisciplinary research contained in the special issue was undertaken are discussed. Principal methods, primary research sites and data collection used by numerous investigators during 1997-1999 are then presented. Scientists from about 20 US, five European (four French and one Dutch), and three Mexican agencies and institutions have collaborated closely to make the research leading to this special issue a reality. The SALSA Program has served as a model of interagency cooperation by breaking new ground in the approach to large scale interdisciplinary science with relatively limited resources.

  20. Climatic Variables Do Not Directly Predict Spider Richness and Abundance in Semiarid Caatinga Vegetation, Brazil.

    PubMed

    Carvalho, Leonardo S; Sebastian, Nicholas; Araújo, Helder F P; Dias, Sidclay C; Venticinque, Eduardo; Brescovit, Antonio D; Vasconcellos, Alexandre

    2015-02-01

    Spiders are abundant in tropical ecosystems and exert predatory pressure on a wide variety of invertebrate populations and also serve as prey for many others organisms, being part of complex interrelationships influenced directly and indirectly by a myriad of factors. We examined the influence of biotic (i.e., prey availability) and abiotic (i.e., temperature, precipitation, relative humidity, real evapotranspiration) factors on species richness and abundance during a two-year period in the semiarid Caatinga vegetation in northeastern Brazil. Data were analyzed through partial autocorrelation functions, cross correlations, and a path analysis. A total of 2522 spiders were collected with beating tray, pit-fall traps, and malaise traps, comprising 91 species and 34 families. Spider abundance peaked in the rainy season. Our results suggest that total invertebrate abundance has a direct influence on spider richness and abundance, whereas the effects of precipitation were mainly indirectly related to most spider assemblage parameters. The increase in vegetation cover with the rainy season in the Caatinga provides more breeding and foraging sites for spiders and stimulates their activities. Additionally, rainfall in arid and semiarid ecosystems stimulated the activity and reproduction of many herbivore and detritivore invertebrates dependent on plant biomass and necromass consumption, leading to an increase in spider prey availability.

  1. Soil Moisture Retrieval Using a Two-Dimenional L-Band Synthetic Aperture Radiometer in a Semi-Arid Environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surface soil moisture was retrieved from L-band radiometer data collected in semi-arid regions during the Soil Moisture Experiment in 2004 (SMEX04). The two-dimensional synthetic aperture radiometer (2D-STAR) was flown over regional-scale study sites located in Arizona, USA and Sonora, Mexico. The s...

  2. Microbial Community Structure and Enzyme Activities in Semiarid Agricultural Soils

    NASA Astrophysics Data System (ADS)

    Acosta-Martinez, V. A.; Zobeck, T. M.; Gill, T. E.; Kennedy, A. C.

    2002-12-01

    The effect of agricultural management practices on the microbial community structure and enzyme activities of semiarid soils of different textures in the Southern High Plains of Texas were investigated. The soils (sandy clay loam, fine sandy loam and loam) were under continuous cotton (Gossypium hirsutum L.) or in rotations with peanut (Arachis hypogaea L.), sorghum (Sorghum bicolor L.) or wheat (Triticum aestivum L.), and had different water management (irrigated or dryland) and tillage (conservation or conventional). Microbial community structure was investigated using fatty acid methyl ester (FAME) analysis by gas chromatography and enzyme activities, involved in C, N, P and S cycling of soils, were measured (mg product released per kg soil per h). The activities of b-glucosidase, b-glucosaminidase, alkaline phosphatase, and arylsulfatase were significantly (P<0.05) increased in soils under cotton rotated with sorghum or wheat, and due to conservation tillage in comparison to continuous cotton under conventional tillage. Principal component analysis showed FAME profiles of these soils separated distinctly along PC1 (20 %) and PC2 (13 %) due to their differences in soil texture and management. No significant differences were detected in FAME profiles due to management practices for the same soils in this sampling period. Enzyme activities provide early indications of the benefits in microbial populations and activities and soil organic matter under crop rotations and conservation tillage in comparison to the typical practices in semiarid regions of continuous cotton and conventional tillage.

  3. Quantifying Understory Transpiration in a Semiarid Riparian Area

    NASA Astrophysics Data System (ADS)

    McGuire, R. R.; Scott, R. L.

    2005-12-01

    One of the most challenging components to estimate when determining water budgets in semiarid basins is riparian evapotranspiration (ET). Much research has been conducted upon riparian overstory vegetation in these areas; however understory vegetation water use has been ignored due to measurement difficulties and the belief that its quantity is negligible. To better understand the magnitude of understory water use in a semiarid riparian ecosystem, we measured whole plant transpiration of the dominant understory shrub, seep willow (Baccharis salicifolia), along a perennial reach of the San Pedro River in southeastern Arizona. . Shrub transpiration was monitored using the heat balance sap flow technique and was compared under two environmental conditions: a shrub patch located in a more open environment with decreased overstory canopy cover, and a more closed shrub patch situated more directly underneath a cottonwood (Populus fremontii) forest canopy. Despite the differences in atmospheric forcing, stand-level transpiration at both sites was similar and indicated that transpiration was rarely demand-limited. Growing season transpiration totals for seep willow were much greater than precipitation and of comparable magnitude to the overstory cottonwood transpiration. These results suggest that understory water use can be an important component of a riparian water budget, especially in regions like the western U.S. where evaporative demand is often high.

  4. Bartonella species pathogenic for humans infect pets, free-ranging wild mammals and their ectoparasites in the Caatinga biome, Northeastern Brazil: a serological and molecular study.

    PubMed

    Fontalvo, Mariana Campos; Favacho, Alexsandra Rodrigues de Mendonça; Araujo, Andreina de Carvalho; Santos, Naylla Mayana Dos; Oliveira, Glauber Meneses Barboza de; Aguiar, Daniel Moura; Lemos, Elba Regina Sampaio de; Horta, Mauricio Claudio

    2017-02-27

    This study verified the occurrence of Bartonella spp. in dogs, cats, wild mammals and their ectoparasites in Petrolina and Lagoa Grande Counties, Pernambuco, located in a semi-arid region in Northeastern Brazil. Anti-Bartonella spp. antibodies were detected by indirect immunofluorescence assay (IFA) in 24.8% of dogs (27/109) and in 15% of cats (6/40). Bartonella sp. DNA was identified by PCR performed on DNA extracted from blood and ectoparasites using primers targeting Bartonella sp. gltA and ribC genes in 100% (9/9) of Pulex irritans from Cerdocyon thous, 57.4% (35/61) of P. irritans from dogs, 2.3% (1/43) of Ctenocephalides felis felis from dogs, 53.3% (24/45) of C. felis felis from cats, and 10% (1/10) of Polyplax spp. from Thrichomys apereoides. DNA sequencing identified Bartonella clarridgeiae and Bartonella henselae in C. felis felis from cats, Bartonella rochalimae in P. irritans from dog and C. thous, and Bartonella vinsoni berkhofii in P. irritans from dog.

  5. Out with the garbage: the parasitic strategy of the mantisfly Plega hagenella mass-infesting colonies of the eusocial bee Melipona subnitida in northeastern Brazil

    NASA Astrophysics Data System (ADS)

    Maia-Silva, Camila; Hrncir, Michael; Koedam, Dirk; Machado, Renato Jose Pires; Imperatriz-Fonseca, Vera Lucia

    2013-01-01

    Between April and June of 2012 mantisflies ( Plega hagenella) were found to be extensively parasitizing the nests of two groups of managed colonzies of eusocial stingless bees ( Melipona subnitida) in the semi-arid region of northeastern Brazil. The mantisfly larvae developed inside closed brood cells of the bee comb, where each mantispid larva fed on the bee larva or pupa present in a single brood cell. Mature mantispid larvae pupated inside silken cocoons spun in place within their hosts' brood cells then emerged as pharate adults inside the bee colony. Pharate adults were never attacked and killed by host colony workers. Instead, colony workers picked up the pharates and removed them from the nest unharmed, treating them similar to the way that the general refuse is removed from the nest. Adult mantispids subsequently eclosed from their pupal exuviae outside the nest. Manipulative experiments showed that post-eclosion adult mantispids placed back within active bee colonies were quickly attacked and killed. These observations demonstrate that pharate and post-eclosion adults of P. hagenella are perceived differently by colony workers and that delayed adult eclosion is an important functional element in the parasitic life strategy of P. hagenella, allowing adults to escape without injury from the bee colonies they parasitize.

  6. Ecology and Geography of Plague Transmission Areas in Northeastern Brazil

    PubMed Central

    Giles, John; Peterson, A. Townsend; Almeida, Alzira

    2011-01-01

    Plague in Brazil is poorly known and now rarely seen, so studies of its ecology are difficult. We used ecological niche models of historical (1966-present) records of human plague cases across northeastern Brazil to assess hypotheses regarding environmental correlates of plague occurrences across the region. Results indicate that the apparently focal distribution of plague in northeastern Brazil is indeed discontinuous, and that the causes of the discontinuity are not necessarily only related to elevation—rather, a diversity of environmental dimensions correlate to presence of plague foci in the region. Perhaps most interesting is that suitable areas for plague show marked seasonal variation in photosynthetic mass, with peaks in April and May, suggesting links to particular land cover types. Next steps in this line of research will require more detailed and specific examination of reservoir ecology and natural history. PMID:21245925

  7. Ecology and geography of plague transmission areas in northeastern Brazil.

    PubMed

    Giles, John; Peterson, A Townsend; Almeida, Alzira

    2011-01-04

    Plague in Brazil is poorly known and now rarely seen, so studies of its ecology are difficult. We used ecological niche models of historical (1966-present) records of human plague cases across northeastern Brazil to assess hypotheses regarding environmental correlates of plague occurrences across the region. Results indicate that the apparently focal distribution of plague in northeastern Brazil is indeed discontinuous, and that the causes of the discontinuity are not necessarily only related to elevation-rather, a diversity of environmental dimensions correlate to presence of plague foci in the region. Perhaps most interesting is that suitable areas for plague show marked seasonal variation in photosynthetic mass, with peaks in April and May, suggesting links to particular land cover types. Next steps in this line of research will require more detailed and specific examination of reservoir ecology and natural history.

  8. Hydrodynamic and salinity evolution of groundwaters during artificial recharge within semi-arid coastal aquifers: A case study of El Khairat aquifer system in Enfidha (Tunisian Sahel)

    NASA Astrophysics Data System (ADS)

    Ketata, Mouna; Gueddari, Moncef; Bouhlila, Rachida

    2014-09-01

    In common with most coastal aquifers, the El Khairat aquifer suffers the imbalance between recharge and intense exploitation and the extent of agricultural activity. As it is part of the Tunisian Sahel, the Enfidha region has a semiarid climate with very irregular rainfall which makes the groundwater resources quite fragile. This region has major difficulties in managing its water resources which are in decline, especially since, for the last decades, their renewal by rainwater has no longer been sufficient to re-establish the equilibrium. In such a case, the artificial recharge of aquifers by water from dams is a credible alternative to preserve the water resources against marine intrusion and pronounced fall in the piezometric level. The present investigation, based on available data, is aimed to monitoring the piezometry of the El Khairat aquifer during artificial recharge operations (2002-2005) by water from the dam and to identify the impact of the artificial recharge on groundwater quality. The results of this monitoring have shown that the artificial recharge realized between 2002 and 2005, had for effect an increase of the piezometric level of the phreatic aquifer of +0.4 to +2.63 m, especially in the “Ain Garci” zone. The piezometric level of the deep aquifer has also recorded an important increase reaching +3.82 m. After artificial recharge of the aquifer, the spatial distribution of the salinity shows quite low salinity values (lower than 2 g/l) in the western and north-eastern parts of the aquifer, the zone of artificial recharge, whereas the highest ones are found especially in the coastal zones and at the boundaries of the Sebkha where they exceeded 3 g/l. Moreover, we note a slight salinity reduction toward a central zone of the aquifer. Indeed, the zone characterized by salinity lower than 2 g/l and situated near the recharge site becomes more extensive.

  9. Northeastern Pennsylvania Retrospective Case Study Fact Sheet

    EPA Pesticide Factsheets

    EPA conducted a retrospective case study in northeastern Pennsylvania to investigate reported instances of contaminated drinking water resources in areas where hydraulic fracturing activities occurred

  10. Crustal structure of northeastern California

    NASA Astrophysics Data System (ADS)

    Zucca, John J.; Fuis, Gary S.; Milkereit, Bernd; Mooney, Walter D.; Catchings, Rufus D.

    1986-06-01

    In 1981, the U.S. Geological Survey conducted a seismic refraction survey of northeastern California designed to characterize the structure in four geologic provinces: the Klamath Mountains, Cascade Range, Modoc Plateau, and Basin and Range provinces. The survey consisted of north-south lines in the Klamath Mountains and Modoc Plateau provinces, northwest-southeast lines centered on Mount Shasta and Medicine Lake volcano, and an east-west line linking all the profiles. All lines except the east-west line ranged in length from 125 to 140 km, contained three shot points, and were recorded by 100 instruments. The east-west line was 260 km long, contained six shot points, and was recorded by 200 instruments. The Klamath and Modoc lines yielded the simplest models. The Klamath model is finely layered from the surface to at least 14-km depth, consisting of a series of high-velocity layers (6.1-6.7 km/s), ranging in thickness from 1 to 4 km, with alternating positive and negative velocity gradients. A layer with an unreversed velocity of 7.0 km/s extends from 14 km downward to an unknown depth. The Modoc model, in contrast, is thickly layered and has lower velocity at all depths down to 25 km. The uppermost layer, 4.5 km thick, consists of low-velocity material (2-4.5 km/s). Velocity beneath this layer is much higher (6.2 km/s) and increases slowly with depth. A small velocity step (to 6.4 km/s) is seen at 11 km, and a larger step (to 7.0 km/s) is seen at 25 km depth. Moho is probably 38-45 km deep under the Modoc Plateau, but its depth is unknown under the Klamath Mountains. Models for the Shasta and Medicine Lake lines show special features including low velocity (less than 3.5 km/s) in the edifice of Mount Shasta but high velocity (5.6 km/s) at shallow depth (1-2 km) under the summit of Medicine Lake volcano. The model for the east-west line consists of a western part similar to the Klamath model, an eastern part similar to the Modoc model, and laterally changing

  11. Helminths infection patterns in a lizard (Tropidurus hispidus) population from a semiarid neotropical area: associations between female reproductive allocation and parasite loads.

    PubMed

    Galdino, Conrado A B; Ávila, Robson W; Bezerra, Castiele H; Passos, Daniel C; Melo, Gabriela C; Zanchi-Silva, Djan

    2014-12-01

    This study reports helminth infection patterns of the lizard Tropidurus hispidus from an area of semiarid caatinga in northeastern Brazil (Ceará state). The lizard population was parasitized by 8 helminth species, and the species composition of the component community resembles that found for other Neotropical lizards. The prevalence of parasites was higher for males compared with females, whereas no relation was found between intensity of infection of 2 parasites (Parapharyngodon alvarengai and Physaloptera lutzi) and the lizards body size. For reproductive females, parasite infection intensity was negatively correlated to reproductive investment.

  12. Seroprevalence of Toxoplasma gondii among turkeys on family farms in the state of Northeastern Brazil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of the present study was to investigate the prevalence of antibodies against Toxoplasma gondii in turkeys and chickens on family farms in the semi-arid region of the state of Pernambuco, Brazil. In order to do so, 204 sera samples from turkeys were analyzed using the Modified Agglutination T...

  13. Water balance of two earthen landfill caps in a semi-arid climate

    SciTech Connect

    Khire, M.V.; Benson, C.H.; Bosscher, P.J.

    1997-12-31

    Water balance data are presented that were obtained from two earthen cap test sections located in a semi-arid region. The test sections were constructed on a municipal solid waste landfill in East Wenatchee, Washington, USA. One test section represents a traditional resistive barrier, and is constructed with a compacted silty clay barrier 60 cm thick and a vegetated silty clay surface layer 15 cm thick. The other test section represents a capillary barrier and has a sand layer 75 cm thick overlain by a 15-cm-thick vegetated surface layer of silt. Extensive hydrological and meteorological data have been collected since November 1992. Unsaturated hydraulic properties of soils, hydrologic parameters, and vegetation have been extensively characterized. Results of the study show that capillary barriers can be effective caps in semi-arid and arid regions. They are also cheaper to construct and can perform better than traditional resistive barriers.

  14. Intra-seasonal NDVI change projections in semi-arid Africa

    USGS Publications Warehouse

    Funk, Christopher C.; Brown, Molly E.

    2006-01-01

    Early warning systems (EWS) tend to focus on the identification of slow onset disasters such famine and epidemic disease. Since hazardous environmental conditions often precede disastrous outcomes by many months, effective monitoring via satellite and in situ observations can successfully guide mitigation activities. Accurate short term forecasts of NDVI could increase lead times, making early warning earlier. This paper presents a simple empirical model for making 1 to 4 month NDVI projections. These statistical projections are based on parameterized satellite rainfall estimates (RFE) and relative humidity demand (RHD). A quasi-global, 1 month ahead, 1° study demonstrates reasonable accuracies in many semi-arid regions. In Africa, a 0.1° cross-validated skill assessment quantifies the technique's applicability at 1 to 4 month forecast intervals. These results suggest that useful projections can be made over many semi-arid, food insecure regions of Africa, with plausible extensions to drought prone areas of Asia, Australia and South America.

  15. Monitoring the variations of evapotranspiration due to land use/cover change in a semiarid shrubland

    NASA Astrophysics Data System (ADS)

    Gong, Tingting; Lei, Huimin; Yang, Dawen; Jiao, Yang; Yang, Hanbo

    2017-02-01

    Evapotranspiration (ET) is an important process in the hydrological cycle, and vegetation change is a primary factor that affects ET. In this study, we analyzed the annual and inter-annual characteristics of ET using continuous observation data from eddy covariance (EC) measurement over 4 years (1 July 2011 to 30 June 2015) in a semiarid shrubland of Mu Us Sandy Land, China. The Normalized Difference Vegetation Index (NDVI) was demonstrated as the predominant factor that influences the seasonal variations in ET. Additionally, during the land degradation and vegetation rehabilitation processes, ET and normalized ET both increased due to the integrated effects of the changes in vegetation type, topography, and soil surface characteristics. This study could improve our understanding of the effects of land use/cover change on ET in the fragile ecosystem of semiarid regions and provide a scientific reference for the sustainable management of regional land and water resources.

  16. Geographic Clustering of Leishmaniasis in Northeastern Brazil1

    PubMed Central

    Guimarães, Luiz H.; Machado, Paulo R.L.; Lessa, Marcus; Lessa, Hélio A.; Lago, Ednaldo; Ritt, Guilherme; Góes-Neto, Aristóteles; Schriefer, Ana L.F.; Riley, Lee W.; Carvalho, Edgar M.

    2009-01-01

    To determine whether disease outcomes and clades of Leishmania braziliensis genotypes are associated, we studied geographic clustering of clades and most severe disease outcomes for leishmaniasis during 1999–2003 in Corte de Pedra in northeastern Brazil. Highly significant differences were observed in distribution of mucosal leishmaniasis versus disseminated leishmaniasis (DL) (p<0.0001). Concordance was observed between distribution of these disease forms and clades of L. braziliensis genotypes shown to be associated with these disease forms. We also detected spread of DL over this region and an inverse correlation between frequency of recent DL diagnoses and distance to a previous DL case. These findings indicate that leishmaniasis outcomes are distributed differently within transmission foci and show that DL is rapidly spreading in northeastern Brazil. PMID:19523284

  17. How does the global Moderate Resolution Imaging Spectroradiometer (MODIS) Fraction of Photosynthetically Active Radiation (FPAR) product relate to regionally developed land cover and vegetation products in a semi-arid Australian savanna?

    NASA Astrophysics Data System (ADS)

    Schoettker, Birte; Phinn, Stuart; Schmidt, Michael

    2010-06-01

    Spatio-temporally variable information on total vegetation cover is highly relevant to water quality and land management in river catchments adjacent to the Great Barrier Reef, Australia. A time series of the global Moderate Resolution Imaging Spectroradiometer (MODIS) Fraction of Photosynthetically Active Radiation (FPAR; 2000-2006) and its underlying biome classification (MOD12Q1) were compared to national land cover and regional, remotely sensed products in the dry-tropical Burdekin River. The MOD12Q1 showed reasonable agreement with a classification of major vegetation groups for 94% of the study area. We then compared dry-seasonal, quality controlled MODIS FPAR observations to (i) Landsat-based woody foliage projective cover (wFPC) (2004) and (ii) MODIS bare ground index (BGI) observations (2001-2003). Statistical analysis of the MODIS FPAR revealed a significant sensitivity to Landsat wFPC-based Vegetation Structural Categories (VSC) and VSC-specific temporal variability over the 2004 dry season. The MODIS FPAR relation to 20 coinciding MODIS BGI dry-seasonal observations was significant (ρ < 0.001) for homogeneous areas of low wFPC. Our results show that the global MODIS FPAR can be used to identify VSC, represent VSC-specific variability of PAR absorption, and indicate that the amount, structure, and optical properties of green and non-green vegetation components contribute to the MODIS FPAR signal.

  18. MULTI-SCALE CONTROLS ON AND CONSEQUENCES OF AEOLIAN PROCESSES IN LANDSCAPE CHANGE IN ARID AND SEMI-ARID ENVIRONMENTS

    EPA Science Inventory

    This paper reviews the controls on aeolian processes and their consequences at plant-interspace, patch-landscape, and regional-global scales. Based on this review, we define the requirements for a cross-scale model of wind erosion in structurally complex arid and semiarid ecosyst...

  19. Does the conversion of grasslands to row crop production in semi-arid areas threaten global food supplies?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the world’s semi-arid regions, high crop demands have produced short term economic incentives to convert native grasslands to dryland row crop production, while genetic enhancements and equipment have reduced the risk of crop failure. The objectives of this paper were to discuss: 1) the importanc...

  20. Characteristics of burns conducted under modified prescriptions to mitigate limited fuels in a semi-arid grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In semiarid grasslands of the North American Great Plains, fire has traditionally been viewed as having few management applications, and quantitative measurements of fire behavior in the low fuel loads characteristic of this region are lacking. More recently, land managers have recognized potential...

  1. Patch scale turbulence over dryland and irrigated surfaces in a semi-arid landscape during BEAREX08

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantifying turbulent fluxes of heat and water vapor over heterogeneous surfaces presents unique challenges. For example, in many arid and semi-arid regions, parcels of irrigated cropland are juxtaposed with hot, dry surfaces. Contrasting surface conditions can result in the advection of warm dry ai...

  2. A Survey of Rural Primary School Music Education in Northeastern China

    ERIC Educational Resources Information Center

    Sun, Zuodong; Leung, Bo Wah

    2014-01-01

    China has been instituting national basic education curriculum reforms since 2001. This study provides an updated understanding of present-day, rural primary school music education in Northeastern China's Tonghua region. A total of 126 rural primary music teachers and 674 students from 28 primary schools in the region were surveyed using a…

  3. Simulation of Multiscale Ground-Water Flow in Part of the Northeastern San Joaquin Valley, California

    USGS Publications Warehouse

    Phillips, Steven P.; Green, Christopher T.; Burow, Karen R.; Shelton, Jennifer L.; Rewis, Diane L.

    2007-01-01

    The transport and fate of agricultural chemicals in a variety of environmental settings is being evaluated as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment Program. One of the locations being evaluated is a 2,700-km2 (square kilometer) regional study area in the northeastern San Joaquin Valley surrounding the city of Modesto, an area dominated by irrigated agriculture in a semi-arid climate. Ground water is a key source of water for irrigation and public supply, and exploitation of this resource has altered the natural flow system. The aquifer system is predominantly alluvial, and an unconfined to semiconfined aquifer overlies a confined aquifer in the southwestern part of the study area; these aquifers are separated by the lacustrine Corcoran Clay. A regional-scale 16-layer steady-state model of ground-water flow in the aquifer system in the regional study area was developed to provide boundary conditions for an embedded 110-layer steady-state local-scale model of part of the aquifer system overlying the Corcoran Clay along the Merced River. The purpose of the local-scale model was to develop a better understanding of the aquifer system and to provide a basis for simulation of reactive transport of agricultural chemicals. The heterogeneity of aquifer materials was explicitly incorporated into the regional and local models using information from geologic and drillers? logs of boreholes. Aquifer materials were differentiated in the regional model by the percentage of coarse-grained sediments in a cell, and in the local model by four hydrofacies (sand, silty sand, silt, and clay). The calibrated horizontal hydraulic conductivity values of the coarse-grained materials in the zone above the Corcoran Clay in the regional model and of the sand hydrofacies used in the local model were about equal (30?80 m/d [meter per day]), and the vertical hydraulic conductivity values in the same zone of the regional model (median of 0.012 m/d), which is

  4. Increased Prevalence of Trichinella spp., Northeastern Germany, 2008

    PubMed Central

    Pannwitz, Gunter; Balicka-Ramisz, Aleksandra; Nöckler, Karsten

    2010-01-01

    In 2008, a Trichinella spp. outbreak occurred on a small family-owned pig farm in Mecklenburg–Western Pomerania in northeastern Germany. To obtain epidemiologic information on this outbreak, we determined that after 2005 the prevalence of Trichinella spp. in wild boars has increased in this region of Germany. We discuss the potential role of the raccoon dog in the increase in Trichinella spp. prevalence in the sylvatic cycle in this region. We believe that this increase could pose a threat to pigs kept in back yard conditions, and we provide recommendations to ensure public health safety. PMID:20507743

  5. Aridity Modulates N Availability in Arid and Semiarid Mediterranean Grasslands

    PubMed Central

    Delgado-Baquerizo, Manuel; Maestre, Fernando T.; Gallardo, Antonio; Quero, José L.; Ochoa, Victoria; García-Gómez, Miguel; Escolar, Cristina; García-Palacios, Pablo; Berdugo, Miguel; Valencia, Enrique; Gozalo, Beatriz; Noumi, Zouhaier; Derak, Mchich; Wallens