WorldWideScience

Sample records for achieve high foraging

  1. Temporal effects of hunting on foraging behavior of an apex predator: Do bears forego foraging when risk is high?

    Science.gov (United States)

    Hertel, Anne G; Zedrosser, Andreas; Mysterud, Atle; Støen, Ole-Gunnar; Steyaert, Sam M J G; Swenson, Jon E

    2016-12-01

    Avoiding predators most often entails a food cost. For the Scandinavian brown bear (Ursus arctos), the hunting season coincides with the period of hyperphagia. Hunting mortality risk is not uniformly distributed throughout the day, but peaks in the early morning hours. As bears must increase mass for winter survival, they should be sensitive to temporal allocation of antipredator responses to periods of highest risk. We expected bears to reduce foraging activity at the expense of food intake in the morning hours when risk was high, but not in the afternoon, when risk was low. We used fine-scale GPS-derived activity patterns during the 2 weeks before and after the onset of the annual bear hunting season. At locations of probable foraging, we assessed abundance and sugar content, of bilberry (Vaccinium myrtillus), the most important autumn food resource for bears in this area. Bears decreased their foraging activity in the morning hours of the hunting season. Likewise, they foraged less efficiently and on poorer quality berries in the morning. Neither of our foraging measures were affected by hunting in the afternoon foraging bout, indicating that bears did not allocate antipredator behavior to times of comparably lower risk. Bears effectively responded to variation in risk on the scale of hours. This entailed a measurable foraging cost. The additive effect of reduced foraging activity, reduced forage intake, and lower quality food may result in poorer body condition upon den entry and may ultimately reduce reproductive success.

  2. Bust economics: foragers choose high quality habitats in lean times

    Directory of Open Access Journals (Sweden)

    Sonny S. Bleicher

    2016-01-01

    Full Text Available In environments where food resources are spatially variable and temporarily impoverished, consumers that encounter habitat patches with different food density should focus their foraging initially where food density is highest before they move to patches where food density is lower. Increasing missed opportunity costs should drive individuals progressively to patches with lower food density as resources in the initially high food density patches deplete. To test these expectations, we assessed the foraging decisions of two species of dasyurid marsupials (dunnarts: Sminthopsis hirtipes and S. youngsoni during a deep drought, or bust period, in the Simpson Desert of central Australia. Dunnarts were allowed access to three patches containing different food densities using an interview chamber experiment. Both species exhibited clear preference for the high density over the lower food density patches as measured in total harvested resources. Similarly, when measuring the proportion of resources harvested within the patches, we observed a marginal preference for patches with initially high densities. Models analyzing behavioral choices at the population level found no differences in behavior between the two species, but models analyzing choices at the individual level uncovered some variation. We conclude that dunnarts can distinguish between habitat patches with different densities of food and preferentially exploit the most valuable. As our observations were made during bust conditions, experiments should be repeated during boom times to assess the foraging economics of dunnarts when environmental resources are high.

  3. Poor Results for High Achievers

    Science.gov (United States)

    Bui, Sa; Imberman, Scott; Craig, Steven

    2012-01-01

    Three million students in the United States are classified as gifted, yet little is known about the effectiveness of traditional gifted and talented (G&T) programs. In theory, G&T programs might help high-achieving students because they group them with other high achievers and typically offer specially trained teachers and a more advanced…

  4. Multi-objective behavioural mechanisms are adopted by foraging animals to achieve several optimality goals simultaneously.

    Science.gov (United States)

    Wajnberg, Eric

    2012-03-01

    1. Animals foraging for resources are under a variety of selective pressures, and separate optimality models have been developed predicting the optimal reproductive strategies they should adopt. 2. In most cases, the proximate behavioural mechanisms adopted to achieve such optimality goals have been identified. This is the case, for example, for optimal patch time and sex allocation in insect parasitoids. However, behaviours modelled within this framework have mainly been studied separately, even though real animals have to optimize some behaviours simultaneously. 3. For this reason, it would be better if proximate behavioural rules were designed to attain several goals simultaneously. Despite their importance, such multi-objective proximate rules remain to be discovered. 4. Based on experiments on insect parasitoids that simultaneously examine their optimal patch time and sex allocation strategies, it is shown here that animals can adopt multi-objective behavioural mechanisms that appear consistent with the two optimal goals simultaneously. 5. Results of computer simulations demonstrate that these behavioural mechanisms are indeed consistent with optimal reproductive strategies and have thus been most likely selected over the course of the evolutionary time.

  5. Model of high-productive varieties in forage pea

    Directory of Open Access Journals (Sweden)

    Valentin Kosev

    2015-06-01

    Full Text Available A linear equation of regression was used for establishment of the influence of quantitative characteristics on the grain productivity in forage pea and for development of a model for breeding work. The model for pea plant with high productivity was characterized by average height of 60–70 cm, 8–10 formed pods, 30–40 seeds per plant and 160–260 g in regard to 1000-seed weight. The obtained results showed that the greatest effect on grain productivity had the seed number per plant, first pod height and 1000-seed weight. Kristal variety had high ecological plasticity and could be considered as close to an ideal type, suitable for growing under wide range of environments. Pleven 4 and Rezonator were determined as high-productive varieties and with low stability, Kerpo and Pikardi - as low-productive but stable varieties. Druzba was identified as unstable and low-productive variety.

  6. The foraging benefits of being fat in a highly migratory marine mammal.

    Science.gov (United States)

    Adachi, Taiki; Maresh, Jennifer L; Robinson, Patrick W; Peterson, Sarah H; Costa, Daniel P; Naito, Yasuhiko; Watanabe, Yuuki Y; Takahashi, Akinori

    2014-12-22

    Foraging theory predicts that breath-hold divers adjust the time spent foraging at depth relative to the energetic cost of swimming, which varies with buoyancy (body density). However, the buoyancy of diving animals varies as a function of their body condition, and the effects of these changes on swimming costs and foraging behaviour have been poorly examined. A novel animal-borne accelerometer was developed that recorded the number of flipper strokes, which allowed us to monitor the number of strokes per metre swam (hereafter, referred to as strokes-per-metre) by female northern elephant seals over their months-long, oceanic foraging migrations. As negatively buoyant seals increased their fat stores and buoyancy, the strokes-per-metre increased slightly in the buoyancy-aided direction (descending), but decreased significantly in the buoyancy-hindered direction (ascending), with associated changes in swim speed and gliding duration. Overall, the round-trip strokes-per-metre decreased and reached a minimum value when seals achieved neutral buoyancy. Consistent with foraging theory, seals stayed longer at foraging depths when their round-trip strokes-per-metre was less. Therefore, neutrally buoyant divers gained an energetic advantage via reduced swimming costs, which resulted in an increase in time spent foraging at depth, suggesting a foraging benefit of being fat.

  7. Improved forage strategies for high-yielding dairy cows in Vietnam : report of a workshop

    NARCIS (Netherlands)

    Wouters, A.P.; Lee, van der J.

    2013-01-01

    This report presents results of the workshop "Improved forage strategies for high-yielding dairy cows in Vietnam" which was held with Vietnamese stakeholders on January 17-18, 2013 in Ho Chi Minh City as part of the project "Forage and Grass Production for Dairy Development in Vietnam" funded by the

  8. Bat guilds, a concept to classify the highly diverse foraging and echolocation behaviors of microchiropteran bats

    Directory of Open Access Journals (Sweden)

    Annette eDenzinger

    2013-07-01

    Full Text Available Throughout evolution the foraging and echolocation behaviors as well as the motor systems of bats have been adapted to the tasks they have to perform while searching and acquiring food. When bats exploit the same class of environmental resources in a similar way, they perform comparable tasks and thus share similar adaptations independent of their phylogeny. Species with similar adaptations are assigned to guilds or functional groups. Habitat type and foraging mode mainly determine the foraging tasks and thus the adaptations of bats. Therefore we use habitat type and foraging mode to define seven guilds. The habitat types open, edge and narrow space are defined according to the bats’ echolocation behavior in relation to the distance between bat and background or food item and background. Bats foraging in the aerial, trawling, flutter detecting, or active gleaning mode use only echolocation to acquire their food. When foraging in the passive gleaning mode bats do not use echolocation but rely on sensory cues from the food item to find it. Bat communities often comprise large numbers of species with a high diversity in foraging areas, foraging modes, and diets. The assignment of species living under similar constraints into guilds identifies pattern of community structure and helps to understand the factors that underlie the organization of highly diverse bat communities. Bat species from different guilds do not compete for food as they differ in their foraging behavior and in the environmental resources they use. However, sympatric living species belonging to the same guild often exploit the same class of resources. To avoid competition they should differ in their niche dimensions. The fine grain structure of bat communities below the rather coarse classification into guilds is determined by mechanisms that result in niche partitioning.

  9. Mathematics Achievement in High- and Low-Achieving Secondary Schools

    Science.gov (United States)

    Mohammadpour, Ebrahim; Shekarchizadeh, Ahmadreza

    2015-01-01

    This paper identifies the amount of variance in mathematics achievement in high- and low-achieving schools that can be explained by school-level factors, while controlling for student-level factors. The data were obtained from 2679 Iranian eighth graders who participated in the 2007 Trends in International Mathematics and Science Study. Of the…

  10. Ultra-High Foraging Rates of Harbor Porpoises Make Them Vulnerable to Anthropogenic Disturbance

    DEFF Research Database (Denmark)

    Wisniewska, Danuta Maria; Johnson, Mark; Teilmann, Jonas

    2016-01-01

    and anthropogenic disturbance. Yet for most marine species, foraging interactions cannot be observed directly. The high costs of thermoregulation in water requires that small marine mammals have elevated energy intakes compared to similar-sized terrestrial mammals. The combination of high food requirements...

  11. Drought associated poisoning of cattle in South Texas by the high quality forage legume Leucaena leucocephala.

    Science.gov (United States)

    Anderson, R C; Anderson, T J; Nisbet, D J; Kibbe, A S; Elrod, D; Wilkinson, G

    2001-04-01

    Approximately 80 head of yearling cattle grazing on 680 acres exhibited signs of Leucaena leucocephala toxicosis, which was confirmed in 3 animals by detection of 3-hydroxy-4 (IH)-pyridone, the metabolite of the poisonous principle mimosine, in their urine. The animals had grazed leucaena almost exclusively due to lack of alternative forage resulting from drought conditions. Toxicosis from this otherwise high quality forage would likely not have occurred had animals consumed lower amounts of leucaena and could probably have been prevented, as it has been elsewhere, had the animals been colonized with Synergistes jonesii, a beneficial ruminal bacterium capable of degrading the toxic metabolites.

  12. In search of annual legumes to improve forage sorghum yield and nutritive value in the southern high plains

    Science.gov (United States)

    Livestock production is significant in the Southern High Plains of the USA and demand is increasing for greater forage dry matter (DM) yield with increased nutritive value. Forage sorghum (FS)[Sorghum bicolor (L.) Moench] is commonly used, although, it is low in crude protein (CP) and high in fiber....

  13. High precision during food recruitment of experienced (reactivated) foragers in the stingless bee Scaptotrigona mexicana (Apidae, Meliponini)

    Science.gov (United States)

    Sánchez, Daniel; Nieh, James C.; Hénaut, Yann; Cruz, Leopoldo; Vandame, Rémy

    Several studies have examined the existence of recruitment communication mechanisms in stingless bees. However, the spatial accuracy of location-specific recruitment has not been examined. Moreover, the location-specific recruitment of reactivated foragers, i.e., foragers that have previously experienced the same food source at a different location and time, has not been explicitly examined. However, such foragers may also play a significant role in colony foraging, particularly in small colonies. Here we report that reactivated Scaptotrigona mexicana foragers can recruit with high precision to a specific food location. The recruitment precision of reactivated foragers was evaluated by placing control feeders to the left and the right of the training feeder (direction-precision tests) and between the nest and the training feeder and beyond it (distance-precision tests). Reactivated foragers arrived at the correct location with high precision: 98.44% arrived at the training feeder in the direction trials (five-feeder fan-shaped array, accuracy of at least +/-6° of azimuth at 50 m from the nest), and 88.62% arrived at the training feeder in the distance trials (five-feeder linear array, accuracy of at least +/-5 m or +/-10% at 50 m from the nest). Thus, S. mexicana reactivated foragers can find the indicated food source at a specific distance and direction with high precision, higher than that shown by honeybees, Apis mellifera, which do not communicate food location at such close distances to the nest.

  14. High academic achievement in psychotic students.

    Science.gov (United States)

    Defries, Z; Grothe, L

    1978-02-01

    The authors studied 21 schizophrenic and borderline college students who achieved B+ or higher grade averages and underwent psychotherapy while in college. High academic achievement was found to provide relief from feelings of worthlessness and ineffectuality resulting from poor relationships with parents, siblings, and peers. Psychotherapy and the permissive yet supportive college atmosphere reinforced the students' self-esteem.

  15. Foraging behavior of humpback whales: kinematic and respiratory patterns suggest a high cost for a lunge.

    Science.gov (United States)

    Goldbogen, Jeremy A; Calambokidis, John; Croll, Donald A; Harvey, James T; Newton, Kelly M; Oleson, Erin M; Schorr, Greg; Shadwick, Robert E

    2008-12-01

    Lunge feeding in rorqual whales is a drag-based feeding mechanism that is thought to entail a high energetic cost and consequently limit the maximum dive time of these extraordinarily large predators. Although the kinematics of lunge feeding in fin whales supports this hypothesis, it is unclear whether respiratory compensation occurs as a consequence of lunge-feeding activity. We used high-resolution digital tags on foraging humpback whales (Megaptera novaengliae) to determine the number of lunges executed per dive as well as respiratory frequency between dives. Data from two whales are reported, which together performed 58 foraging dives and 451 lunges. During one study, we tracked one tagged whale for approximately 2 h and examined the spatial distribution of prey using a digital echosounder. These data were integrated with the dive profile to reveal that lunges are directed toward the upper boundary of dense krill aggregations. Foraging dives were characterized by a gliding descent, up to 15 lunges at depth, and an ascent powered by steady swimming. Longer dives were required to perform more lunges at depth and these extended apneas were followed by an increase in the number of breaths taken after a dive. Maximum dive durations during foraging were approximately half of those previously reported for singing (i.e. non-feeding) humpback whales. At the highest lunge frequencies (10 to 15 lunges per dive), respiratory rate was at least threefold higher than that of singing humpback whales that underwent a similar degree of apnea. These data suggest that the high energetic cost associated with lunge feeding in blue and fin whales also occurs in intermediate sized rorquals.

  16. Student Perceptions of High-Achieving Classmates

    Science.gov (United States)

    Händel, Marion; Vialle, Wilma; Ziegler, Albert

    2013-01-01

    The reported study investigated students' perceptions of their high-performing classmates in terms of intelligence, social skills, and conscientiousness in different school subjects. The school subjects for study were examined with regard to cognitive, physical, and gender-specific issues. The results show that high academic achievements in…

  17. Foraging segregation and genetic divergence between geographically proximate colonies of a highly mobile seabird

    Science.gov (United States)

    Wiley, Anne E.; Welch, Andreanna J.; Ostrom, P.H.; James, Helen F.; Stricker, C.A.; Fleischer, R.C.; Gandhi, H.; Adams, J.; Ainley, D.G.; Duvall, F.; Holmes, N.; Hu, D.; Judge, S.; Penniman, J.; Swindle, K.A.

    2012-01-01

    Foraging segregation may play an important role in the maintenance of animal diversity, and is a proposed mechanism for promoting genetic divergence within seabird species. However, little information exists regarding its presence among seabird populations. We investigated genetic and foraging divergence between two colonies of endangered Hawaiian petrels (Pterodroma sandwichensis) nesting on the islands of Hawaii and Kauai using the mitochondrial Cytochrome b gene and carbon, nitrogen and hydrogen isotope values (?? 13C, ?? 15N and ??D, respectively) of feathers. Genetic analyses revealed strong differentiation between colonies on Hawaii and Kauai, with ?? ST = 0. 50 (p < 0. 0001). Coalescent-based analyses gave estimates of <1 migration event per 1,000 generations. Hatch-year birds from Kauai had significantly lower ?? 13C and ?? 15N values than those from Hawaii. This is consistent with Kauai birds provisioning chicks with prey derived from near or north of the Hawaiian Islands, and Hawaii birds provisioning young with prey from regions of the equatorial Pacific characterized by elevated ?? 15N values at the food web base. ?? 15N values of Kauai and Hawaii adults differed significantly, indicating additional foraging segregation during molt. Feather ??D varied from -69 to 53???. This variation cannot be related solely to an isotopically homogeneous ocean water source or evaporative water loss. Instead, we propose the involvement of salt gland excretion. Our data demonstrate the presence of foraging segregation between proximately nesting seabird populations, despite high species mobility. This ecological diversity may facilitate population coexistence, and its preservation should be a focus of conservation strategies. ?? 2011 Springer-Verlag (outside the USA).

  18. Shallow food for deep divers: Dynamic foraging behavior of male sperm whales in a high latitude habitat

    DEFF Research Database (Denmark)

    Teloni, Valeria; Johnson, M.P.; Miller, P.J.O.

    2008-01-01

    Groups of female and immature sperm whales live at low latitudes and show a stereotypical diving and foraging behavior with dives lasting about 45 min to depths of between 400 and 1200 m. In comparison, physically mature male sperm whales migrate to high latitudes where little is known about...... their foraging behavior and ecology. Here we use acoustic recording tags to study the diving and acoustic behavior of male sperm whales foraging off northern Norway. Sixty-five hours of tag data provide detailed information about the movements and sound repertoire of four male sperm whales performing 83 dives...... epipelagic prey, is consistent with the hypothesis that male sperm whales may migrate to high latitudes to access a productive, multi-layered foraging habitat....

  19. Achieving High Performance Perovskite Solar Cells

    Science.gov (United States)

    Yang, Yang

    2015-03-01

    Recently, metal halide perovskite based solar cell with the characteristics of rather low raw materials cost, great potential for simple process and scalable production, and extreme high power conversion efficiency (PCE), have been highlighted as one of the most competitive technologies for next generation thin film photovoltaic (PV). In UCLA, we have realized an efficient pathway to achieve high performance pervoskite solar cells, where the findings are beneficial to this unique materials/devices system. Our recent progress lies in perovskite film formation, defect passivation, transport materials design, interface engineering with respect to high performance solar cell, as well as the exploration of its applications beyond photovoltaics. These achievements include: 1) development of vapor assisted solution process (VASP) and moisture assisted solution process, which produces perovskite film with improved conformity, high crystallinity, reduced recombination rate, and the resulting high performance; 2) examination of the defects property of perovskite materials, and demonstration of a self-induced passivation approach to reduce carrier recombination; 3) interface engineering based on design of the carrier transport materials and the electrodes, in combination with high quality perovskite film, which delivers 15 ~ 20% PCEs; 4) a novel integration of bulk heterojunction to perovskite solar cell to achieve better light harvest; 5) fabrication of inverted solar cell device with high efficiency and flexibility and 6) exploration the application of perovskite materials to photodetector. Further development in film, device architecture, and interfaces will lead to continuous improved perovskite solar cells and other organic-inorganic hybrid optoelectronics.

  20. What Characterises High Achieving Students’ Mathematical Reasoning?

    OpenAIRE

    Haavold, Per Øystein

    2011-01-01

    This study investigates high achieving students’ mathematical reasoning when given an unfamiliar trigonometric equation. The findings indicate that the students’ way of thinking is strongly linked with imitative reasoning and only when they received some form of guidance, were they able to display flexible and creative mathematical reasoning.

  1. Low and high achievers in math

    DEFF Research Database (Denmark)

    Overgaard, Steffen; Tonnesen, Pia Beck; Weng, Peter

    2015-01-01

    In this session we will present the results of the preliminary analysis of the qualitative and quantitative data, which can be used to enhance the teaching of low and high mathematics achievers so as to increase their mathematical knowledge and confidence....

  2. Devclopment of the Forage Riees WithHigh Protein Gontent in Hunan

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The meaning of the high protein forage rices Rices may be classified by itsuses as human'sfood.animal's on poultry's feed,or the raw materials of various industries.For ricesused as people's food.its breeding objectives are focused on the varietal characters such as medium amylose content .high rale of head rice.hyaline smoothmilled grains and delicious taste:for those used in making rice meal.beer,gourmet powder,etc.specially on high amylose content:while in wine making,it should be focused on big white belly and white beart,but low protein content in particular.As for the rices used as feed,the most important is its high rate of pre -protein in the brown rice ,leaving its grain appearance out of consideration.Thcrefore,the so called forage rice (FR)sgiykd be a kind of paddy rice with high pre-protein content of brown rice(≥8.25%)and high grain yicld (≥8.25t/ha),to be used as the composition of the animal feed by applying cultivation management oplimized under the suitable growth duration and strong pest resistance.

  3. Early predictors of high school mathematics achievement.

    Science.gov (United States)

    Siegler, Robert S; Duncan, Greg J; Davis-Kean, Pamela E; Duckworth, Kathryn; Claessens, Amy; Engel, Mimi; Susperreguy, Maria Ines; Chen, Meichu

    2012-07-01

    Identifying the types of mathematics content knowledge that are most predictive of students' long-term learning is essential for improving both theories of mathematical development and mathematics education. To identify these types of knowledge, we examined long-term predictors of high school students' knowledge of algebra and overall mathematics achievement. Analyses of large, nationally representative, longitudinal data sets from the United States and the United Kingdom revealed that elementary school students' knowledge of fractions and of division uniquely predicts those students' knowledge of algebra and overall mathematics achievement in high school, 5 or 6 years later, even after statistically controlling for other types of mathematical knowledge, general intellectual ability, working memory, and family income and education. Implications of these findings for understanding and improving mathematics learning are discussed.

  4. Achieving high performance on the Intel Paragon

    Energy Technology Data Exchange (ETDEWEB)

    Greenberg, D.S.; Maccabe, B.; Riesen, R.; Wheat, S.; Womble, D.

    1993-11-01

    When presented with a new supercomputer most users will first ask {open_quotes}How much faster will my applications run?{close_quotes} and then add a fearful {open_quotes}How much effort will it take me to convert to the new machine?{close_quotes} This paper describes some lessons learned at Sandia while asking these questions about the new 1800+ node Intel Paragon. The authors conclude that the operating system is crucial to both achieving high performance and allowing easy conversion from previous parallel implementations to a new machine. Using the Sandia/UNM Operating System (SUNMOS) they were able to port a LU factorization of dense matrices from the nCUBE2 to the Paragon and achieve 92% scaled speed-up on 1024 nodes. Thus on a 44,000 by 44,000 matrix which had required over 10 hours on the previous machine, they completed in less than 1/2 hour at a rate of over 40 GFLOPS. Two keys to achieving such high performance were the small size of SUNMOS (less than 256 kbytes) and the ability to send large messages with very low overhead.

  5. Unfulfilled Potential: High-Achieving Minority Students and the High School Achievement Gap in Math

    Science.gov (United States)

    Kotok, Stephen

    2017-01-01

    This study uses multilevel modeling to examine a subset of the highest performing 9th graders and explores the extent that achievement gaps in math widen for high performing African American and Latino students and their high performing White and Asian peers during high school. Using nationally representative data from the High School Longitudinal…

  6. Bed disturbance via foraging fish increases bedload transport during subsequent high flows and is controlled by fish size and species

    Science.gov (United States)

    Pledger, A. G.; Rice, S. P.; Millett, J.

    2016-01-01

    Benthic foraging by fish can modify the nature and rates of fine sediment accrual and the structure and topography of coarse-grained fluvial substrates, with the potential to alter bed material characteristics, particle entrainment thresholds, and bedload transport fluxes. However, knowledge of what controls the nature, extent, and intensity of benthic foraging and the consequent influence of these controls on geomorphic impact remain rudimentary. An ex-situ experiment utilising Barbel Barbus barbus and Chub Leuciscus cephalus extended previous work by considering the role of fish size and species as controls of sediment disturbance by foraging and the implications for bed material characteristics and bedload transport. In a laboratory flume, changes in bed microtopography and structure were measured when a water-worked bed of 5.6-22.6 mm gravels was exposed to four size classes of Barbel (4-5″, 5-6″, 6-8″, 8-10″ in length) and a single size class of Chub (8-10″). In line with other studies that have investigated animal size as a control of zoogeomorphic agency, increasing the size of Barbel had a significant effect on measured disturbance and transport metrics. Specifically, the area of disturbed substrate, foraging depth, and the fish's impact on microtopographic roughness and imbrication all increased as a function of fish size. In a comparison of the foraging effects of like-sized Barbel and Chub, 8-10″ in length, Barbel foraged a larger area of the test bed and had a greater impact on microtopographic roughness and sediment structure. Relative to water-worked beds that were not foraged, bed conditioning by both species was associated with increased bedload transport during the subsequent application of high flows. However, the bedload flux after foraging by Barbel, which is a specialist benthivore, was 150% higher than that following foraging by Chub, which feed opportunistically from the bed, and the total transported mass of sediment was 98

  7. Using DNA metabarcoding to investigate honey bee foraging reveals limited flower use despite high floral availability.

    Science.gov (United States)

    de Vere, Natasha; Jones, Laura E; Gilmore, Tegan; Moscrop, Jake; Lowe, Abigail; Smith, Dan; Hegarty, Matthew J; Creer, Simon; Ford, Col R

    2017-02-16

    Understanding which flowers honey bees (Apis mellifera) use for forage can help us to provide suitable plants for healthy honey bee colonies. Accordingly, honey DNA metabarcoding provides a valuable tool for investigating pollen and nectar collection. We investigated early season (April and May) floral choice by honey bees provided with a very high diversity of flowering plants within the National Botanic Garden of Wales. There was a close correspondence between the phenology of flowering and the detection of plants within the honey. Within the study area there were 437 genera of plants in flower during April and May, but only 11% of these were used. Thirty-nine plant taxa were recorded from three hives but only ten at greater than 1%. All three colonies used the same core set of native or near-native plants, typically found in hedgerows and woodlands. The major plants were supplemented with a range of horticultural species, with more variation in plant choice between the honey bee colonies. We conclude that during the spring, honey bees need access to native hedgerows and woodlands to provide major plants for foraging. Gardens provide supplementary flowers that may increase the nutritional diversity of the honey bee diet.

  8. Using DNA metabarcoding to investigate honey bee foraging reveals limited flower use despite high floral availability

    Science.gov (United States)

    de Vere, Natasha; Jones, Laura E.; Gilmore, Tegan; Moscrop, Jake; Lowe, Abigail; Smith, Dan; Hegarty, Matthew J.; Creer, Simon; Ford, Col R.

    2017-01-01

    Understanding which flowers honey bees (Apis mellifera) use for forage can help us to provide suitable plants for healthy honey bee colonies. Accordingly, honey DNA metabarcoding provides a valuable tool for investigating pollen and nectar collection. We investigated early season (April and May) floral choice by honey bees provided with a very high diversity of flowering plants within the National Botanic Garden of Wales. There was a close correspondence between the phenology of flowering and the detection of plants within the honey. Within the study area there were 437 genera of plants in flower during April and May, but only 11% of these were used. Thirty-nine plant taxa were recorded from three hives but only ten at greater than 1%. All three colonies used the same core set of native or near-native plants, typically found in hedgerows and woodlands. The major plants were supplemented with a range of horticultural species, with more variation in plant choice between the honey bee colonies. We conclude that during the spring, honey bees need access to native hedgerows and woodlands to provide major plants for foraging. Gardens provide supplementary flowers that may increase the nutritional diversity of the honey bee diet. PMID:28205632

  9. Achieving High Data Throughput in Research Networks

    Institute of Scientific and Technical Information of China (English)

    WarrenMatthews; LesCottrell

    2001-01-01

    After less than a year of operation ,the BaBar experiment at SLAC has collected almost 100 million particle collision events in a database approaching 165TB.Around 20 TB of data has been exported via the Internet to the BaBar regional center at IN2P3 in Lyon,France,and around 40TB of simulated data has been imported from the Lawrence Livermore National Laboratory(LLNL),BaBar Collaborators plan to double data collection each year and export a third of the data to IN2P3.So within a few years the SLAC OC3 (155Mbps) connection will be fully utilized by file transfer to France alone.Upgrades to infrastructure is essential and detailed understanding of performance issues and the requirements for reliable high throughput transfers is critical.In this talk results from active and passive monitoring and direct measurements of throughput will be reviewed.Methods for achieving the ambitious requirements will be discussed.

  10. High Involvement Mothers of High Achieving Children: Potential Theoretical Explanations

    Science.gov (United States)

    Hunsaker, Scott L.

    2013-01-01

    In American society, parents who have high aspirations for the achievements of their children are often viewed by others in a negative light. Various pejoratives such as "pushy parent," "helicopter parent," "stage mother," and "soccer mom" are used in the common vernacular to describe these parents. Multiple…

  11. Achieving high luminosity in the Fermilab Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, S.D.

    1991-05-01

    Fermilab has embarked upon a program, christened Fermilab III, to raise the luminosity in the Tevatron proton-antiproton collider over the next five years by at least a factor of thirty beyond the currently achieved level of 1.6{times}10{sup 30}cm{sup {minus}2}sec{sup {minus}1}. Components of the program include implementation of electrostatic separators, Antiproton Source improvements, installation of cold compressors, doubling the existing linac output energy, and the construction of a new accelerator--the Fermilab Main Injector. Basic limitations in the achievement of higher luminosity in the Tevatron, the strategy developed to achieve the Fermilab III goals, and the evolution of luminosity throughout the period will be discussed. 1 fig., 2 tabs.

  12. Does High School Homework Increase Academic Achievement?

    Science.gov (United States)

    Kalenkoski, Charlene Marie; Pabilonia, Sabrina Wulff

    2017-01-01

    Although previous research has shown that homework improves students' academic achievement, the majority of these studies use data on students' homework time from retrospective questionnaires, which may be less accurate than time-diary data. We use data from the combined Child Development Supplement (CDS) and the Transition to Adulthood Survey…

  13. Factors Implicated in High Mathematics Achievement

    Science.gov (United States)

    Forgasz, Helen J.; Hill, Janelle C.

    2013-01-01

    The most recent Program for International Student Assessment (PISA) (2009) mathematical literacy results provide evidence that in Western English-speaking countries, including Australia, the gender gap in achievement appears to be widening in favour of males. In the study reported in this article, the aim was to explore the effects of gender,…

  14. Psychosocial Keys to African American Achievement? Examining the Relationship between Achievement and Psychosocial Variables in High Achieving African Americans

    Science.gov (United States)

    Dixson, Dante D.; Roberson, Cyrell C. B.; Worrell, Frank C.

    2017-01-01

    Grit, growth mindset, ethnic identity, and other group orientation are four psychosocial variables that have been associated with academic achievement in adolescent populations. In a sample of 105 high achieving African American high school students (cumulative grade point average [GPA] > 3.0), we examined whether these four psychosocial…

  15. High Dynamic Range Color Image Enhancement Using Fuzzy Logic and Bacterial Foraging

    Directory of Open Access Journals (Sweden)

    Om Prakash Verma

    2011-09-01

    Full Text Available High dynamic range images contain both the underexposed and the overexposed regions. The enhancement of the underexposed and the overexposed regions is the main concern of this paper. Two new transformation functions are proposed to modify the fuzzy membership values of under and the overexposed regions of an image respectively.For the overexposed regions, a rectangular hyperbolic function is used while for the underexposed regions, an S-function is applied. The shape and range of these functions can be controlled by the parameters involved, which are optimized using the bacterial foraging optimization algorithm so as to obtain the enhanced image. The hue, saturation, and intensity (HSV color space is employed for the purpose of enhancement, where the hue component is preserved to keep the original color composition intact. This approach is applicable to a degraded image of mixed type. On comparison, the proposed transforms yield better results than the existing transformation functions17 for both the underexposed and the overexposed regions.Defence Science Journal, 2011, 61(5, pp.462-472, DOI:http://dx.doi.org/10.14429/dsj.61.1184

  16. Differences in foraging ecology align with genetically divergent ecotypes of a highly mobile marine top predator.

    Science.gov (United States)

    Jeglinski, Jana W E; Wolf, Jochen B W; Werner, Christiane; Costa, Daniel P; Trillmich, Fritz

    2015-12-01

    Foraging differentiation within a species can contribute to restricted gene flow between ecologically different groups, promoting ecological speciation. Galapagos sea lions (Zalophus wollebaeki) show genetic and morphological divergence between the western and central archipelago, possibly as a result of an ecologically mediated contrast in the marine habitat. We use global positioning system (GPS) data, time-depth recordings (TDR), stable isotope and scat data to compare foraging habitat characteristics, diving behaviour and diet composition of Galapagos sea lions from a western and a central colony. We consider both juvenile and adult life stages to assess the potential role of ontogenetic shifts that can be crucial in shaping foraging behaviour and habitat choice for life. We found differences in foraging habitat use, foraging style and diet composition that aligned with genetic differentiation. These differences were consistent between juvenile and adult sea lions from the same colony, overriding age-specific behavioural differences. Our study contributes to an understanding of the complex interaction of ecological condition, plastic behavioural response and genetic make-up of interconnected populations.

  17. Adverse foraging conditions may impact body mass and survival of a high Arctic seabird

    Science.gov (United States)

    Harding, A.M.A.; Welcker, J.; Steen, H.; Hamer, K.C.; Kitaysky, A.S.; Fort, J.; Talbot, S.L.; Cornick, L.A.; Karnovsky, N.J.; Gabrielsen, G.W.; Gremillet, D.

    2011-01-01

    Tradeoffs between current reproduction and future survival are widely recognized, but may only occur when food is limited: when foraging conditions are favorable, parents may be able to reproduce without compromising their own survival. We investigated these tradeoffs in the little auk (Alle alle), a small seabird with a single-egg clutch. During 2005-2007, we examined the relationship between body mass and survival of birds breeding under contrasting foraging conditions at two Arctic colonies. We used corticosterone levels of breeding adults as a physiological indicator of the foraging conditions they encountered during each reproductive season. We found that when foraging conditions were relatively poor (as reflected in elevated levels of corticosterone), parents ended the reproductive season with low body mass and suffered increased post-breeding mortality. A positive relationship between body mass and post-breeding survival was found in one study year; light birds incurred higher survival costs than heavy birds. The results of this study suggest that reproducing under poor foraging conditions may affect the post-breeding survival of long-lived little auks. They also have important demographic implications because even a small change in adult survival may have a large effect on populations of long-lived species. ?? 2011 Springer-Verlag.

  18. Early Predictors of High School Mathematics Achievement

    Science.gov (United States)

    Siegler, Robert S.; Duncan, Greg J.; Davis-Kean, Pamela E.; Duckworth, Kathryn; Claessens, Amy; Engel, Mimi; Susperreguy, Maria Ines; Meichu, Chen

    2012-01-01

    Identifying the types of mathematics content knowledge that are most predictive of students' long-term learning is essential for improving both theories of mathematical development and mathematics education. To identify these types of knowledge, we examined long-term predictors of high school students' knowledge of algebra and overall mathematics…

  19. Achievement Goals, Learning Strategies and Language Achievement among Peruvian High School Students

    Directory of Open Access Journals (Sweden)

    Lennia Matos

    2007-05-01

    Full Text Available We used an achievement goal framework to study the role of motivation in the academic context of a Peruvian sample of 8th to 10th grade high school students (N = 1505. The purpose of this cross-sectional study was to examine the relationship between students' achievement goals, their use of learning strategies and their academic achievement. Multiple Hierarchical Regressions Analyses identified, as predicted, positive effects of mastery goals, including more use of learning strategies and higher academic achievement, and negative effects of performance avoidance goals, including lower academic achievement. Mixed results were found for pursuing performance approach goals, which predicted a greater use of learning strategies, but were unrelated to academic achievement. The present findings support the external validity of achievement goal theory in a sample of students from a culture that is understudied in the achievement goal literature in particular and the motivational literature in general.

  20. High forage quality helps maintain resilience to gastrointestinal parasites in sheep and goats

    Science.gov (United States)

    Condensed tannins (CT) in browse and forage plants can have positive or negative effects on livestock health and performance, depending on the type and concentration of CT present in the diet. Historically, bloating in ruminants was reduced or eliminated when grazing legumes that contained CT. Con...

  1. Highly productive forage legume stands show no positive biodiversity effect on yield and N2-fixation

    DEFF Research Database (Denmark)

    Dhamala, Nawa Raj; Eriksen, Jørgen; Carlsson, Georg

    2017-01-01

    derived most (around 85%) of their N from atmospheric N fixation (%Ndfa). However, no positive effect of species diversity was found in any of the mixtures. Species composition of the forage legume mixtures affected the amount of N from N fixation by affecting DM production and N accumulation...

  2. Achievement Goals, Learning Strategies and Language Achievement among Peruvian High School Students

    OpenAIRE

    Lennia Matos; Willy Lens; Maarten Vansteenkiste

    2007-01-01

    We used an achievement goal framework to study the role of motivation in the academic context of a Peruvian sample of 8th to 10th grade high school students (N = 1505). The purpose of this cross-sectional study was to examine the relationship between students' achievement goals, their use of learning strategies and their academic achievement. Multiple Hierarchical Regressions Analyses identified, as predicted, positive effects of mastery goals, including more use of learning strategies and hi...

  3. Cooperative Bacterial Foraging Optimization

    Directory of Open Access Journals (Sweden)

    Hanning Chen

    2009-01-01

    Full Text Available Bacterial Foraging Optimization (BFO is a novel optimization algorithm based on the social foraging behavior of E. coli bacteria. This paper presents a variation on the original BFO algorithm, namely, the Cooperative Bacterial Foraging Optimization (CBFO, which significantly improve the original BFO in solving complex optimization problems. This significant improvement is achieved by applying two cooperative approaches to the original BFO, namely, the serial heterogeneous cooperation on the implicit space decomposition level and the serial heterogeneous cooperation on the hybrid space decomposition level. The experiments compare the performance of two CBFO variants with the original BFO, the standard PSO and a real-coded GA on four widely used benchmark functions. The new method shows a marked improvement in performance over the original BFO and appears to be comparable with the PSO and GA.

  4. Adaptive Bacterial Foraging Optimization

    Directory of Open Access Journals (Sweden)

    Hanning Chen

    2011-01-01

    Full Text Available Bacterial Foraging Optimization (BFO is a recently developed nature-inspired optimization algorithm, which is based on the foraging behavior of E. coli bacteria. Up to now, BFO has been applied successfully to some engineering problems due to its simplicity and ease of implementation. However, BFO possesses a poor convergence behavior over complex optimization problems as compared to other nature-inspired optimization techniques. This paper first analyzes how the run-length unit parameter of BFO controls the exploration of the whole search space and the exploitation of the promising areas. Then it presents a variation on the original BFO, called the adaptive bacterial foraging optimization (ABFO, employing the adaptive foraging strategies to improve the performance of the original BFO. This improvement is achieved by enabling the bacterial foraging algorithm to adjust the run-length unit parameter dynamically during algorithm execution in order to balance the exploration/exploitation tradeoff. The experiments compare the performance of two versions of ABFO with the original BFO, the standard particle swarm optimization (PSO and a real-coded genetic algorithm (GA on four widely-used benchmark functions. The proposed ABFO shows a marked improvement in performance over the original BFO and appears to be comparable with the PSO and GA.

  5. Utilization of complete rumen modifier on sheep fed high fibrous forages.

    Directory of Open Access Journals (Sweden)

    Amlius Thalib

    2010-06-01

    Full Text Available A research to improve livestock productivity and lower enteric methane production on ruminant was conducted by manipulation approach on rumen system using a complete rumen modifier (CRM. An in vivo experiment was carried out using twenty four sheep ( mean weight 18 kg which were distributed into 3 treatment groups of feed additive: I. control ( without treatment: K; II: K + CRM-LG; III: K + CRM-EL. Diet given consisted of fermented rice straw (ad libitum + concentrate containing 16 % protein (400 g/head/day, and drinking water was given ad libitum. The experiment was conducted for 14 weeks based on completely randomized design. By the end of the experiment, animals were placed in the metabolism cages for 2 weeks (ie. 1 week for adaptation and 1 week for data collection. Rumen liquid of each treated animal was taken for the measurement of rumen characteristics. Parameter measuremed were: total gas production; gas composition of CO2 and CH4; in vitro DMD; NH3 and VFA contents; pH; bacterial and protozoal counts; consumption/ DMI; in vivo DMD; ADG and FCR. The results showed that productivity of sheep was improved by CRM treatments followed by lowered enteric methane production. The ADG values of CRM treatments (71.4 to 73.5 g were significantly higher (P < 0.05 than that of control (50 g. The improvement of average daily gain was followed by a better feed conversion (P < 0.05 (ie. 10.6 vs. 12.8. The CRM treatments lowered the percentage of CH4 by 24% compared to Control (P < 0.05. The total and composition of VFA of CRM-treated rumen liquor were significantly different (P<0.05 compared to that of rumen liquor of Control (ie. the total VFA: 85.3 vs 73.5 mM and the percentage of acetic acid: 67.8 vs 60.3%. It is concluded that CRM treatment resulted in positive effects on growth of ruminant fed high fibrous forages such as rice straw and could lower enteric methane production.

  6. An evaluation of the accuracy and precision of methane prediction equations for beef cattle fed high-forage and high-grain diets.

    Science.gov (United States)

    Escobar-Bahamondes, P; Oba, M; Beauchemin, K A

    2017-01-01

    The study determined the performance of equations to predict enteric methane (CH4) from beef cattle fed forage- and grain-based diets. Many equations are available to predict CH4 from beef cattle and the predictions vary substantially among equations. The aims were to (1) construct a database of CH4 emissions for beef cattle from published literature, and (2) identify the most precise and accurate extant CH4 prediction models for beef cattle fed diets varying in forage content. The database was comprised of treatment means of CH4 production from in vivo beef studies published from 2000 to 2015. Criteria to include data in the database were as follows: animal description, intakes, diet composition and CH4 production. In all, 54 published equations that predict CH4 production from diet composition were evaluated. Precision and accuracy of the equations were evaluated using the concordance correlation coefficient (r c ), root mean square prediction error (RMSPE), model efficiency and analysis of errors. Equations were ranked using a combined index of the various statistical assessments based on principal component analysis. The final database contained 53 studies and 207 treatment means that were divided into two data sets: diets containing ⩾400 g/kg dry matter (DM) forage (n=116) and diets containing ⩽200 g/kg DM forage (n=42). Diets containing between ⩽400 and ⩾200 g/kg DM forage were not included in the analysis because of their limited numbers (n=6). Outliers, treatment means where feed was fed restrictively and diets with CH4 mitigation additives were omitted (n=43). Using the high-forage dataset the best-fit equations were the International Panel on Climate Change Tier 2 method, 3 equations for steers that considered gross energy intake (GEI) and body weight and an equation that considered dry matter intake and starch:neutral detergent fiber with r c ranging from 0.60 to 0.73 and RMSPE from 35.6 to 45.9 g/day. For the high-grain diets, the 5 best

  7. A review on studies in forage in China

    Institute of Scientific and Technical Information of China (English)

    LONG Wenxing; YANG Xiaobo; QI Meiying

    2007-01-01

    A review is made of the achievements in the collection,conservation,and genetic diversity of forage germplasm resources;methods and goals for forage breeding;and development and utilization of forage in China.The current problems based on the researches in forage are analyzed,and some suggestions are put forward.

  8. The Dynamics of Foraging Ants

    Science.gov (United States)

    Baxter, G. William

    2009-03-01

    We experimentally study the foraging of small black ants, Formicinae lasius flavus, in order to describe their foraging behavior mathematically. Individual ants are allowed to forage on a two-dimensional surface in the absence of any food sources. The position of the ant as a function of time is determined using a high-resolution digital camera. Analysis of the average square displacements of many ants suggests that the foraging strategy is a non-reversing random walk. Moreover, the ants do not retrace their steps to return home but instead continue the random walk until it brings them back near their starting point.

  9. Foraging at the edge of the world: low-altitude, high-speed manoeuvering in barn swallows.

    Science.gov (United States)

    Warrick, Douglas R; Hedrick, Tyson L; Biewener, Andrew A; Crandell, Kristen E; Tobalske, Bret W

    2016-09-26

    While prior studies of swallow manoeuvering have focused on slow-speed flight and obstacle avoidance in still air, swallows survive by foraging at high speeds in windy environments. Recent advances in field-portable, high-speed video systems, coupled with precise anemometry, permit measures of high-speed aerial performance of birds in a natural state. We undertook the present study to test: (i) the manner in which barn swallows (Hirundo rustica) may exploit wind dynamics and ground effect while foraging and (ii) the relative importance of flapping versus gliding for accomplishing high-speed manoeuvers. Using multi-camera videography synchronized with wind-velocity measurements, we tracked coursing manoeuvers in pursuit of prey. Wind speed averaged 1.3-2.0 m s(-1) across the atmospheric boundary layer, exhibiting a shear gradient greater than expected, with instantaneous speeds of 0.02-6.1 m s(-1) While barn swallows tended to flap throughout turns, they exhibited reduced wingbeat frequency, relying on glides and partial bounds during maximal manoeuvers. Further, the birds capitalized on the near-earth wind speed gradient to gain kinetic and potential energy during both flapping and gliding turns; providing evidence that such behaviour is not limited to large, fixed-wing soaring seabirds and that exploitation of wind gradients by small aerial insectivores may be a significant aspect of their aeroecology.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'.

  10. Sound production patterns from humpback whales in a high latitude foraging area

    Science.gov (United States)

    Stimpert, Alison K.; Wiley, David N.; Barton, Kira L.; Johnson, Mark P.; Lammers, Marc O.; Au, Whitlow W. L.

    2005-09-01

    Numerous studies have been conducted on humpback whale song, but substantially fewer have focused on the acoustic properties of non-song sound production (i.e., feeding and social sounds). Non-invasive digital acoustic recording tags (DTAGS) were attached to humpback whales on the western North Atlantics Great South Channel feeding grounds during July 2004. Acoustic records totaling 48.4 data hours from four of these attachments were aurally analyzed for temporal trends in whale signal production. A custom automatic detection function was also used to identify occurrences of specific signals and evaluate their temporal consistency. Patterns in sound usage varied by stage of foraging dive and by time of day. Amount of time with signals present was greater at the bottom of dives than during surface periods, indicating that sounds are probably related to foraging at depth. For the two tags that recorded at night, signals were present during a greater proportion of daylight hours than night hours. These results will be compared with previously published trends describing diel patterns in male humpback whale song chorusing on the breeding grounds. Data from the continuation of this research during the summer of 2005 will also be included.

  11. Mobility and Student Achievement in High Poverty Schools

    Science.gov (United States)

    Dalton, Janet Denise

    2013-01-01

    Student mobility is an issue for high poverty schools in the shadow of increased rigor and accountability for student performance. Whereas mobility is not a sole cause for poor achievement, it is a contributing factor for students in poverty who are already considered to be at risk of low achievement. Student mobility creates a hardship for…

  12. Mobility and Student Achievement in High Poverty Schools

    Science.gov (United States)

    Dalton, Janet Denise

    2013-01-01

    Student mobility is an issue for high poverty schools in the shadow of increased rigor and accountability for student performance. Whereas mobility is not a sole cause for poor achievement, it is a contributing factor for students in poverty who are already considered to be at risk of low achievement. Student mobility creates a hardship for…

  13. The "Renaissance Child": High Achievement and Gender in Late Modernity

    Science.gov (United States)

    Skelton, Christine; Francis, Becky

    2012-01-01

    This paper draws on the concept of the "Renaissance Child" to illustrate the ways in which gender influences the opportunities and possibilities of high-achieving pupils. Using data from a study of 12-13-year high-achieving boys and girls based in schools in England, the paper considers the ways in which a group of popular boys was able to show an…

  14. Associations of Future Expectations, Negative Friends, and Academic Achievement in High-Achieving African American Adolescents

    Science.gov (United States)

    Cunningham, Michael; Corprew, Charles S., III; Becker, Jonathan E.

    2009-01-01

    The relations of future expectations (general and academic) to academic outcomes were examined in a sample of 129 African American high-achieving adolescents (majority female participants, n = 92). This study was interested in the multidimensional nature of future expectations. Results from the study confirm the hypothesis that academic future…

  15. Achievement Motivation Training for Potential High School Dropouts. Achievement Motivation Development Project Working Paper Number 4.

    Science.gov (United States)

    McClelland, David C.

    This pilot project sought to determine if instruction in achievement motivation would help potential dropouts to complete their schooling. Subjects were tenth grade students in a suburban Boston high school. A one-week residential course during winter and spring vacations was taken by one group of six boys and a second group of four. Equated…

  16. Student Achievement for Whom? High-Performing and Still "Playing the Game," the Meaning of School Achievement among High Achieving African American Students

    Science.gov (United States)

    Wiggan, Greg

    2014-01-01

    The preponderance of the research on African American students has generally focused on issues of school failure and underperformance. While the literature on high achieving Black students is sparse, very little is known about these students' school experiences and the meanings that they assign to achievement. Using student-based inquiry…

  17. Achievement goals and perfectionism of high school students

    Directory of Open Access Journals (Sweden)

    Milojević Milica

    2009-01-01

    Full Text Available This research has been investigating one of the most contemporary approaches of achievement motivation - Achievement Goal Theory, which uses the construct of achievement goals. The construct of achievement goals involves three types of achievement goals: mastery goals, performance approach goals and performance avoidance goals. The main goal of the research was to examine correlation between perfectionism and its aspects with particular types of achievement goals. Also, the goal was to investigate the difference concerning gender regarding the achievement goals. The sample consisted of 200 senior year high school participants. The following instruments were used: Multi-dimensional scale of perfectionism (MSP and Test of achievement goals (TCP. The research results indicate that there is significant positive correlation between: perfectionism with performance approach goals and performance avoidance goals, concern over mistakes and parental expectations with performance approach goals and performance avoidance goals, personal standards and organization with mastery goals and performance approach goals, parental criticism and doubts about action with performance avoidance goals. Significant negative correlation was found between parental criticism and mastery goals. The results concerning the second goal indicates the female subjects have higher average scores in mastery goals.

  18. High School Employment and Academic Achievement: A Note for Educators

    Science.gov (United States)

    Keister, Mary; Hall, Joshua

    2010-01-01

    Educators are often in a position to affect student decisions to work during the school term. This study reviews and summarizes the literature on the effect that employment during high school has on academic achievement. The available evidence suggests that part-time jobs for high school students are beneficial as long as the number of hours…

  19. Exploring High-Achieving Students' Images of Mathematicians

    Science.gov (United States)

    Aguilar, Mario Sánchez; Rosas, Alejandro; Zavaleta, Juan Gabriel Molina; Romo-Vázquez, Avenilde

    2016-01-01

    The aim of this study is to describe the images that a group of high-achieving Mexican students hold of mathematicians. For this investigation, we used a research method based on the Draw-A-Scientist Test (DAST) with a sample of 63 Mexican high school students. The group of students' pictorial and written descriptions of mathematicians assisted us…

  20. Productivity and carbon footprint of perennial grass-forage legume intercropping strategies with high or low nitrogen fertilizer input.

    Science.gov (United States)

    Hauggaard-Nielsen, Henrik; Lachouani, Petra; Knudsen, Marie Trydeman; Ambus, Per; Boelt, Birte; Gislum, René

    2016-01-15

    A three-season field experiment was established and repeated twice with spring barley used as cover crop for different perennial grass-legume intercrops followed by a full year pasture cropping and winter wheat after sward incorporation. Two fertilization regimes were applied with plots fertilized with either a high or a low rate of mineral nitrogen (N) fertilizer. Life cycle assessment (LCA) was used to evaluate the carbon footprint (global warming potential) of the grassland management including measured nitrous oxide (N2O) emissions after sward incorporation. Without applying any mineral N fertilizer, the forage legume pure stand, especially red clover, was able to produce about 15 t above ground dry matter ha(-1) year(-1) saving around 325 kg mineral Nfertilizer ha(-1) compared to the cocksfoot and tall fescue grass treatments. The pure stand ryegrass yielded around 3t DM more than red clover in the high fertilizer treatment. Nitrous oxide emissions were highest in the treatments containing legumes. The LCA showed that the low input N systems had markedly lower carbon footprint values than crops from the high N input system with the pure stand legumes without N fertilization having the lowest carbon footprint. Thus, a reduction in N fertilizer application rates in the low input systems offsets increased N2O emissions after forage legume treatments compared to grass plots due to the N fertilizer production-related emissions. When including the subsequent wheat yield in the total aboveground production across the three-season rotation, the pure stand red clover without N application and pure stand ryegrass treatments with the highest N input equalled. The present study illustrate how leguminous biological nitrogen fixation (BNF) represents an important low impact renewable N source without reducing crop yields and thereby farmers earnings.

  1. An Analysis of High School Mathematics Achievement and English Language Arts Achievement as Predictors of Science Achievement

    Science.gov (United States)

    Edwards, Anthony C.

    2012-01-01

    Science assessments require students to read and comprehend questions and to solve mathematical problems. The purpose of this study is to determine whether the following variables can be used to predict science achievement: English language arts achievement, mathematics achievement, socioeconomic status (SES), limited English proficiency (LEP)…

  2. An Analysis of High School Mathematics Achievement and English Language Arts Achievement as Predictors of Science Achievement

    Science.gov (United States)

    Edwards, Anthony C.

    2012-01-01

    Science assessments require students to read and comprehend questions and to solve mathematical problems. The purpose of this study is to determine whether the following variables can be used to predict science achievement: English language arts achievement, mathematics achievement, socioeconomic status (SES), limited English proficiency (LEP)…

  3. Relationship between High School Leadership Team Practices and Student Achievement

    Science.gov (United States)

    McInnis, Timothy M.

    2009-01-01

    This study investigated if a relationship existed between student achievement in 10th grade Missouri Assessment Program mathematics and 11th grade communication arts scores in 2007 and high school leadership team perceptions of the extent to which they demonstrated leadership practices. The secondary purpose was to compare perceptional…

  4. Self-Esteem and Academic Achievement of High School Students

    Science.gov (United States)

    Moradi Sheykhjan, Tohid; Jabari, Kamran; Rajeswari, K.

    2014-01-01

    The primary purpose of this study was to determine the influence of self-esteem on academic achievement among high school students in Miandoab City of Iran. The methodology of the research is descriptive and correlation that descriptive and inferential statistics were used to analyze the data. Statistical Society includes male and female high…

  5. Incremental amounts of ground flaxseed decreases milk production but increases n-3 fatty acids and conjugated linoleic acids in dairy cows fed high-forage diets

    Science.gov (United States)

    The objective of this study was to investigate the effect of incremental amounts of ground flaxseed (GFLAX) on milk yield and fatty acids (FA) profile, ruminal metabolism, and nutrient digestibility in dairy cows fed high-forage diets. Twelve multiparous Jersey cows averaging (mean ± SD) 112 ± 68 da...

  6. Incremental amounts of Ascophyllum nodosum meal do not improve animal performance but increase milk iodine output in early lactation dairy cows fed high-forage diets

    Science.gov (United States)

    The objective of this study was to investigate the effects of incremental amounts of Ascophyllum nodosum meal (ANOD) on milk production, milk composition including fatty acids and I, blood metabolites, and nutrient intake and digestibility in early lactation dairy cows fed high-forage diets. Twelve ...

  7. Growth performance and total tract nutrient digestion for Holstein heifers limit-fed diets high in distillers grains with different forage particle size

    Science.gov (United States)

    This study evaluated dairy heifer growth performance and total tract nutrient digestion when fed diets high in dried distillers grains with solubles (DDGS) with different forage particle size. An 8-wk randomized complete block design study was conducted utilizing twenty-two Holstein heifers (123 ±...

  8. Academic achievement of junior high school students with sleep disorders

    Directory of Open Access Journals (Sweden)

    Fijri Auliyanti

    2015-01-01

    Full Text Available Background Sleep disorders are prevalent in adolescents and may influence their academic achievement. To date, no study has been done in Indonesia on academic achievement in students with sleep disorders and its related factors. Objective To assess for relationships between academic achievement and related factors, including gender, motivation and learning strategies, IQ level, maternal educational level, socioeconomic status, family structure, after-hours education program, presence of TV/computer in the bedroom, sleep duration during school days, as well as bedtime and wakeup time difference in junior high school students with sleep disorders. Methods This cross-sectional study was performed from January to March 2013. Subjects were students from five junior high schools in Jakarta who fulfilled the criteria for sleep disorders based on the Sleep Disturbance Scale for Children questionnaire. Results There were 111 study subjects. The prevalence of sleep disorders was 39.7%, mostly in difficulties initiating and maintaining sleep (70.2%. Below-average academic achievement was seen in 47.6% of subjects. Factors significantly related to below-average academic achievement were after-hours education program (prevalence ratio 5.6; 95%CI 1.36 to 23.18; P = 0.017, average IQ level (prevalence ratio 3.26; 95%CI 1.38 to 7.71; P = 0.007, and male gender (prevalence ratio 2.68; 95%CI 1.06 to 6.78; P = 0.037. Conclusion Among junior high school students with sleep disorders, factors related to below-average academic achievement are after-hours education program (more than 2 types, the average IQ level, and male gender. [Paediatr Indones. 2015;55:50-8.].

  9. Academic achievement of junior high school students with sleep disorders

    Directory of Open Access Journals (Sweden)

    Fijri Auliyanti

    2016-07-01

    Full Text Available Background Sleep disorders are prevalent in adolescents and may influence their academic achievement. To date, no study has been done in Indonesia on academic achievement in students with sleep disorders and its related factors. Objective To assess for relationships between academic achievement and related factors, including gender, motivation and learning strategies, IQ level, maternal educational level, socioeconomic status, family structure, after-hours education program, presence of TV/computer in the bedroom, sleep duration during school days, as well as bedtime and wakeup time difference in junior high school students with sleep disorders. Methods This cross-sectional study was performed from January to March 2013. Subjects were students from five junior high schools in Jakarta who fulfilled the criteria for sleep disorders based on the Sleep Disturbance Scale for Children questionnaire. Results There were 111 study subjects. The prevalence of sleep disorders was 39.7%, mostly in difficulties initiating and maintaining sleep (70.2%. Below-average academic achievement was seen in 47.6% of subjects. Factors significantly related to below-average academic achievement were after-hours education program (prevalence ratio 5.6; 95%CI 1.36 to 23.18; P = 0.017, average IQ level (prevalence ratio 3.26; 95%CI 1.38 to 7.71; P = 0.007, and male gender (prevalence ratio 2.68; 95%CI 1.06 to 6.78; P = 0.037. Conclusion Among junior high school students with sleep disorders, factors related to below-average academic achievement are afterhours education program (more than 2 types, the average IQ level, and male gender.

  10. A SELF PROCESS IMPROVEMENT FOR ACHIEVING HIGH SOFTWARE QUALITY

    Directory of Open Access Journals (Sweden)

    DR. SHASHANK.D.JOSHI

    2011-05-01

    Full Text Available Quality has been one of the most important factors in judging any product. Quality means “a degree or grade of excellence or worth”. Quality is a term that is usually described using adjectives. Quality has several attributes to it, some of which can be quantified using metrics. These attributes such as usability, portability, security, performance, reliability etc have different importance in different projects. Different software quality assurance methods & practices have been used in different software projects to attain the true value. Quality is an attribute which is a distinct feature and it differs with people’s perception. Achieving high software quality involves measurement of software metrics and optimization based on estimated values. As the software systems grow larger, complexity ofdesign and implementation increases, and this in turn is more prone to defects and hence directly affect the quality of the systems. However, in any software project, high quality is always desirable, and many projects have specific quality requirements. Achieving high software quality involves measurement of software metrics and optimization based on estimated values. Developing high quality software is governed by factors such as people, process, technology and cost. This paper attempts to present a novel approach towards achieving high software quality in various kinds of projects under given constraints.

  11. The Construction of Black High-Achiever Identities in a Predominantly White High School

    Science.gov (United States)

    Andrews, Dorinda J. Carter

    2009-01-01

    In this article, I examine how black students construct their racial and achievement self-concepts in a predominantly white high school to enact a black achiever identity. By listening to these students talk about the importance of race and achievement to their lives, I came to understand how racialized the task of achieving was for them even…

  12. Parent Involvement Practices of High-Achieving Elementary Science Students

    Science.gov (United States)

    Waller, Samara Susan

    This study addressed a prevalence of low achievement in science courses in an urban school district in Georgia. National leaders and educators have identified the improvement of science proficiency as critical to the future of American industry. The purpose of this study was to examine parent involvement in this school district and its contribution to the academic achievement of successful science students. Social capital theory guided this study by suggesting that students achieve best when investments are made into their academic and social development. A collective case study qualitative research design was used to interview 9 parent participants at 2 elementary schools whose children scored in the exceeds category on the Science CRCT. The research questions focused on what these parents did at home to support their children's academic achievement. Data were collected using a semi-structured interview protocol and analyzed through the categorical aggregation of transcribed interviews. Key findings revealed that the parents invested time and resources in 3 practices: communicating high expectations, supporting and developing key skills, and communicating with teachers. These findings contribute to social change at both the local and community level by creating a starting point for teachers, principals, and district leaders to reexamine the value of parent input in the educational process, and by providing data to support the revision of current parent involvement policies. Possibilities for further study building upon the findings of this study may focus on student perceptions of their parents' parenting as it relates to their science achievement.

  13. Effects of high-sulfur water and clinoptilolite on health and growth performance of steers fed forage-based diets.

    Science.gov (United States)

    Cammack, K M; Wright, C L; Austin, K J; Johnson, P S; Cockrum, R R; Kessler, K L; Olson, K C

    2010-05-01

    Sulfur-induced polioencephalomalacia (sPEM), a neurological disorder affecting ruminants, is associated with consumption of diets with increased S (high-S). High-S water is commonly found in many western states and is a major source of dietary S for grazing cattle. Consumption of high-S water has been associated with sPEM and decreased performance. Identification of a feed supplement that would counteract the negative effects of high-S water would decrease the incidence of sPEM and prevent performance reductions in regions with problematic water sources. The objectives of this study were to 1) determine the effects of administering high-S drinking water to forage-fed feedlot steers on health and performance, and 2) determine the effectiveness of clinoptilolite, a clay mineral with increased cation-exchange capacity, in negating the effects of high-S drinking water. Yearling steers (n = 96; 318.2 +/- 2.1 kg of BW) were randomly assigned to 1 of 4 treatments for a 77-d trial period: control with low-S water (566 mg of SO(4)/L), high-S water (3,651 mg of SO(4)/L), or high-S water plus clinoptilolite supplemented at 2.5 or 5.0% of the diet DM. Feed and water consumption were measured daily, and all steers were weighed on d -2, -1, 29, 53, 76, and 77. Plasma samples were collected on d 0, 58, and 77, and liver samples on d 0 and 77. There was a greater (P treatment groups. In total, 12 cases of sPEM were confirmed by the presence of cortical lesions in steers consuming high-S water. Daily DMI (P = 0.002) and daily water intake (P = 0.001) were less in high-S water steers than control steers. No differences (P >or= 0.546) in ADG or G:F were observed. Plasma Cu decreased (P = 0.029) to a greater magnitude in high-S water steers than the control steers over the 77-d trial period. Mineral analyses of hepatic tissue from randomly selected healthy steers from each treatment group (n = 10 per treatment) showed an interaction (P treatment for Cu, Se, and Zn concentrations

  14. Achieving High Performance on the i860 Microprocessor

    Science.gov (United States)

    Lee, King; Kutler, Paul (Technical Monitor)

    1998-01-01

    The i860 is a high performance microprocessor used in the Intel Touchstone project. This paper proposes a paradigm for programming the i860 that is modelled on the vector instructions of the Cray computers. Fortran callable assembler subroutines were written that mimic the concurrent vector instructions of the Cray. Cache takes the place of vector registers. Using this paradigm we have achieved twice the performance of compiled code on a traditional solve.

  15. Approach to Achieve High Availability in Critical Infrastructure

    Science.gov (United States)

    2015-09-01

    Regardless, current technology includes RFID tags for systems, and tablets can be implemented to assist in real-time updates. Current Wi-Fi technology can...APPROACH TO ACHIEVE HIGH AVAILABILITY IN CRITICAL INFRASTRUCTURE Yew Kee Hoo Senior Engineer, Defence Science and Technology Agency, Singapore B.E...Between Failure MTTF Mean Time to Repair NAVFAC Naval Facilities Engineering Command xvi O&M Operations and Maintenance RFID Radio Frequency

  16. High-quality forage can replace concentrate when cows enter the deposition phase without negative consequences for milk production

    DEFF Research Database (Denmark)

    Hymøller, Lone; Alstrup, Lene; Larsen, Mette Krogh

    2014-01-01

    -RP), and low CFR (30:70) and low CP (14% of DM; LCFR-LP), where RP met the Danish recommendations. Cows were fed concentrate in an automatic milking unit. After calving, cows were fed HCFR-RP until entering deposition, defined as 11 kg (Jersey) or 15 kg (Holstein) of weight gain from the lowest weight after...... cows were assigned to 4 mixed rations in a 2 × 2 factorial design with 2 concentrate to forage ratios (CFR) and 2 CP levels: high CFR (40:60) and recommended CP [16% of dry matter (DM); HCFR-RP], high CFR (40:60) and low CP (14% of DM; HCFR-LP), low CFR (30:70) and recommended CP (16% of DM; LCFR...... calving. Subsequently, cows either remained on HCFR-RP or changed to one of the other mixed rations. Comparing strategies during wk 9 to 30 of lactation showed higher dry matter intake (DMI) of mixed ration on HCFR compared with LCFR and on RP compared with LP. The DMI of the concentrate was higher...

  17. The Impact of Inclusive STEM High Schools on Student Achievement

    Directory of Open Access Journals (Sweden)

    Jennifer Gnagey

    2016-05-01

    Full Text Available This study is one of the first to estimate the impact of “inclusive“ science, technology, engineering, and mathematics (STEM high schools using student-level data. We use multiple statistical strategies to estimate the effect on student achievement from 2 years of attendance at six such high schools in Ohio. The results indicate that two schools had positive effects on science achievement that appear to come at the expense of achievement in social studies. The other schools had negligible or, often, negative effects across both STEM and, particularly, non-STEM subjects. These results are consistent with studies indicating that inclusive STEM schools typically focus on problem-based, personalized learning rather than science and mathematics content. The analysis also reveals the importance of accounting for students’ prior test scores in science, in addition to math and reading, when estimating models that use only 1 year of prior test score data—something that existing studies fail to do.

  18. Achieving High Reliability with People, Processes, and Technology.

    Science.gov (United States)

    Saunders, Candice L; Brennan, John A

    2017-01-01

    High reliability as a corporate value in healthcare can be achieved by meeting the "Quadruple Aim" of improving population health, reducing per capita costs, enhancing the patient experience, and improving provider wellness. This drive starts with the board of trustees, CEO, and other senior leaders who ingrain high reliability throughout the organization. At WellStar Health System, the board developed an ambitious goal to become a top-decile health system in safety and quality metrics. To achieve this goal, WellStar has embarked on a journey toward high reliability and has committed to Lean management practices consistent with the Institute for Healthcare Improvement's definition of a high-reliability organization (HRO): one that is committed to the prevention of failure, early identification and mitigation of failure, and redesign of processes based on identifiable failures. In the end, a successful HRO can provide safe, effective, patient- and family-centered, timely, efficient, and equitable care through a convergence of people, processes, and technology.

  19. Effects of species-diverse high-alpine forage on in vitro ruminal fermentation when used as donor cow's feed or directly incubated.

    Science.gov (United States)

    Khiaosa-Ard, R; Soliva, C R; Kreuzer, M; Leiber, F

    2012-11-01

    Alpine forages are assumed to have specific effects on ruminal digestion when fed to cattle. These effects were investigated in an experiment from two perspectives, either by using such forages as a substrate for incubation or as feed for a rumen fluid donor cow. In total, six 24-h in vitro batch culture runs were performed. Rumen fluid was collected from a non-lactating donor cow after having grazed pastures at ∼2000 m above sea level for 2, 6 and 10 weeks. These 'alpine runs' were compared with three lowland samplings from before and 2 and 6 weeks after the alpine grazing where a silage-concentrate mix was fed. In each run, nine replicates of four forages each were incubated. These forages differed in type and origin (alpine hay, lowland ryegrass hay, grass-maize silage mix, pure hemicellulose) as well as in the content of nutrients. Concentrations of phenolic compounds in the incubated forages were (g/kg dry matter (DM)): 20 (tannin proportion: 0.47), 8 (0.27), 15 (0.52) and 0 (0), respectively. Crude protein was highest in the silage mix and lowest with hemicellulose, whereas the opposite was the case for fiber. The total phenol contents (g/kg DM) for the high altitude and the lowland diet of the donor cow were 27 (tannins: 0.50 of phenols) and 12 (0.27), respectively. Independent of the origin of the rumen fluid, the incubation with alpine hay decreased (P fermentation gas amount, volatile fatty acid (VFA) production as well as ammonia and methane concentrations in fermentation gas (the latter two being not lower when compared with hemicellulose). Alpine grazing of the cow in turn increased (P feeding. Further, alpine grazing decreased protozoal count (P type incubated and feeding period of the donor cow in protozoal counts, acetate:propionate ratio, fermentation gas production and its content of methane, in vitro organic matter digestibility and metabolizable energy. Although increased phenolic compounds were the most consistent common property of the

  20. Unlocking Emergent Talent: Supporting High Achievement of Low-Income, High Ability Students

    Science.gov (United States)

    Olszewski-Kubilius, Paula; Clarenbach, Jane

    2012-01-01

    This report takes a comprehensive look at achievement for low-income promising learners--past, present, and future. At its core, it challenges the nation to move beyond its near-singular focus of achieving minimum performance for all students, to identifying and developing the talent of all students who are capable of high achievement, including…

  1. Achieving High Resolution Timer Events in Virtualized Environment.

    Science.gov (United States)

    Adamczyk, Blazej; Chydzinski, Andrzej

    2015-01-01

    Virtual Machine Monitors (VMM) have become popular in different application areas. Some applications may require to generate the timer events with high resolution and precision. This however may be challenging due to the complexity of VMMs. In this paper we focus on the timer functionality provided by five different VMMs-Xen, KVM, Qemu, VirtualBox and VMWare. Firstly, we evaluate resolutions and precisions of their timer events. Apparently, provided resolutions and precisions are far too low for some applications (e.g. networking applications with the quality of service). Then, using Xen virtualization we demonstrate the improved timer design that greatly enhances both the resolution and precision of achieved timer events.

  2. Factors affecting forage stand establishment

    Directory of Open Access Journals (Sweden)

    Sulc R.M.

    1998-01-01

    Full Text Available Significant advances have been made in our knowledge of forage seed physiology, technology, and stand establishment practices; however, stand establishment continues to be one of the most common production problems affecting forage crops in the USA. There is a need for research on stand establishment of forage crops under abiotic and biotic stress. Although the forage seed industry produces and markets seed of high quality, new methods of assessing seed vigor are needed and their use should be expanded in the industry to enable matching seed lot performance to specific environmental conditions where performance can be maximized. Seed treatment and seed coating are used in the forage seed industry, and studies have shown they are of benefit in some environments. There is an increase in no-tillage seeding of forage crops, but improvements in the no-tillage planting equipment are needed to make them better suited to small seeds. Other recent developments in seeding techniques include broadcasting seed with dry granular and fluid fertilizers, which improves the efficiency of the seeding operation.

  3. Assessing the Effects of Grassland Management on Forage Production and Environmental Quality to Identify Paths to Ecological Intensification in Mountain Grasslands

    Science.gov (United States)

    Loucougaray, Grégory; Dobremez, Laurent; Gos, Pierre; Pauthenet, Yves; Nettier, Baptiste; Lavorel, Sandra

    2015-11-01

    Ecological intensification in grasslands can be regarded as a process for increasing forage production while maintaining high levels of ecosystem functions and biodiversity. In the mountain Vercors massif, where dairy cattle farming is the main component of agriculture, how to achieve forage autonomy at farm level while sustaining environmental quality for tourism and local dairy products has recently stimulated local debate. As specific management is one of the main drivers of ecosystem functioning, we assessed the response of forage production and environmental quality at grassland scale across a wide range of management practices. We aimed to determine which components of management can be harnessed to better match forage production and environmental quality. We sampled the vegetation of 51 grasslands stratified across 13 grassland types. We assessed each grassland for agronomic and environmental properties, measuring forage production, forage quality, and indices based on the abundance of particular plant species such as timing flexibility, apiarian potential, and aromatic plants. Our results revealed an expected trade-off between forage production and environmental quality, notably by stressing the contrasts between sown and permanent grasslands. However, strong within-type variability in both production and environmental quality as well as in flexibility of timing of use suggests possible ways to improve this trade-off at grassland and farm scales. As achieving forage autonomy relies on increasing both forage production and grassland resilience, our results highlight the critical role of the ratio between sown and permanent grasslands as a major path for ecological intensification in mountain grasslands.

  4. Assessing the Effects of Grassland Management on Forage Production and Environmental Quality to Identify Paths to Ecological Intensification in Mountain Grasslands.

    Science.gov (United States)

    Loucougaray, Grégory; Dobremez, Laurent; Gos, Pierre; Pauthenet, Yves; Nettier, Baptiste; Lavorel, Sandra

    2015-11-01

    Ecological intensification in grasslands can be regarded as a process for increasing forage production while maintaining high levels of ecosystem functions and biodiversity. In the mountain Vercors massif, where dairy cattle farming is the main component of agriculture, how to achieve forage autonomy at farm level while sustaining environmental quality for tourism and local dairy products has recently stimulated local debate. As specific management is one of the main drivers of ecosystem functioning, we assessed the response of forage production and environmental quality at grassland scale across a wide range of management practices. We aimed to determine which components of management can be harnessed to better match forage production and environmental quality. We sampled the vegetation of 51 grasslands stratified across 13 grassland types. We assessed each grassland for agronomic and environmental properties, measuring forage production, forage quality, and indices based on the abundance of particular plant species such as timing flexibility, apiarian potential, and aromatic plants. Our results revealed an expected trade-off between forage production and environmental quality, notably by stressing the contrasts between sown and permanent grasslands. However, strong within-type variability in both production and environmental quality as well as in flexibility of timing of use suggests possible ways to improve this trade-off at grassland and farm scales. As achieving forage autonomy relies on increasing both forage production and grassland resilience, our results highlight the critical role of the ratio between sown and permanent grasslands as a major path for ecological intensification in mountain grasslands.

  5. Dancing bees communicate a foraging preference for rural lands in high-level agri-environment schemes.

    Science.gov (United States)

    Couvillon, Margaret J; Schürch, Roger; Ratnieks, Francis L W

    2014-06-02

    Since 1994, more than €41 billion has been spent in the European Union on agri-environment schemes (AESs), which aim to mitigate the effects of anthropomorphic landscape changes via financial incentives for land managers to encourage environmentally friendly practices [1-6]. Surprisingly, given the substantial price tag and mandatory EU member participation [2], there is either a lack of [1] or mixed [1, 2, 7] evidence-based support for the schemes. One novel source of data to evaluate AESs may be provided by an organism that itself may benefit from them. Honeybees (Apis mellifera), important pollinators for crops and wildflowers [8, 9], are declining in parts of the world from many factors, including loss of available forage from agricultural intensification [10-13]. We analyzed landscape-level honeybee foraging ecology patterns over two years by decoding 5,484 waggle dances from bees located in the center of a mixed, urban-rural 94 km(2) area, including lands under government-funded AESs. The waggle dance, a unique behavior performed by successful foragers, communicates to nestmates the most profitable foraging locations [14-16]. After correcting for distance, dances demonstrate that honeybees possess a significant preference for rural land managed under UK Higher Level AESs and a significant preference against rural land under UK Organic Entry Level AESs. Additionally, the two most visited areas contained a National and Local Nature Reserve, respectively. Our study demonstrates that honeybees, with their great foraging range and sensitive response to forage quality, can be used as bioindicators to monitor large areas and provide information relevant to better environmental management. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Honeybee economics: optimisation of foraging in a variable world.

    Science.gov (United States)

    Stabentheiner, Anton; Kovac, Helmut

    2016-06-20

    In honeybees fast and efficient exploitation of nectar and pollen sources is achieved by persistent endothermy throughout the foraging cycle, which means extremely high energy costs. The need for food promotes maximisation of the intake rate, and the high costs call for energetic optimisation. Experiments on how honeybees resolve this conflict have to consider that foraging takes place in a variable environment concerning microclimate and food quality and availability. Here we report, in simultaneous measurements of energy costs, gains, and intake rate and efficiency, how honeybee foragers manage this challenge in their highly variable environment. If possible, during unlimited sucrose flow, they follow an 'investment-guided' ('time is honey') economic strategy promising increased returns. They maximise net intake rate by investing both own heat production and solar heat to increase body temperature to a level which guarantees a high suction velocity. They switch to an 'economizing' ('save the honey') optimisation of energetic efficiency if the intake rate is restricted by the food source when an increased body temperature would not guarantee a high intake rate. With this flexible and graded change between economic strategies honeybees can do both maximise colony intake rate and optimise foraging efficiency in reaction to environmental variation.

  7. Computer Security: SAHARA - Security As High As Reasonably Achievable

    CERN Multimedia

    Stefan Lueders, Computer Security Team

    2015-01-01

    History has shown us time and again that our computer systems, computing services and control systems have digital security deficiencies. Too often we deploy stop-gap solutions and improvised hacks, or we just accept that it is too late to change things.    In my opinion, this blatantly contradicts the professionalism we show in our daily work. Other priorities and time pressure force us to ignore security or to consider it too late to do anything… but we can do better. Just look at how “safety” is dealt with at CERN! “ALARA” (As Low As Reasonably Achievable) is the objective set by the CERN HSE group when considering our individual radiological exposure. Following this paradigm, and shifting it from CERN safety to CERN computer security, would give us “SAHARA”: “Security As High As Reasonably Achievable”. In other words, all possible computer security measures must be applied, so long as ...

  8. Achieving High Resolution Timer Events in Virtualized Environment.

    Directory of Open Access Journals (Sweden)

    Blazej Adamczyk

    Full Text Available Virtual Machine Monitors (VMM have become popular in different application areas. Some applications may require to generate the timer events with high resolution and precision. This however may be challenging due to the complexity of VMMs. In this paper we focus on the timer functionality provided by five different VMMs-Xen, KVM, Qemu, VirtualBox and VMWare. Firstly, we evaluate resolutions and precisions of their timer events. Apparently, provided resolutions and precisions are far too low for some applications (e.g. networking applications with the quality of service. Then, using Xen virtualization we demonstrate the improved timer design that greatly enhances both the resolution and precision of achieved timer events.

  9. Achieving ultra-high temperatures with a resistive emitter array

    Science.gov (United States)

    Danielson, Tom; Franks, Greg; Holmes, Nicholas; LaVeigne, Joe; Matis, Greg; McHugh, Steve; Norton, Dennis; Vengel, Tony; Lannon, John; Goodwin, Scott

    2016-05-01

    The rapid development of very-large format infrared detector arrays has challenged the IR scene projector community to also develop larger-format infrared emitter arrays to support the testing of systems incorporating these detectors. In addition to larger formats, many scene projector users require much higher simulated temperatures than can be generated with current technology in order to fully evaluate the performance of their systems and associated processing algorithms. Under the Ultra High Temperature (UHT) development program, Santa Barbara Infrared Inc. (SBIR) is developing a new infrared scene projector architecture capable of producing both very large format (>1024 x 1024) resistive emitter arrays and improved emitter pixel technology capable of simulating very high apparent temperatures. During earlier phases of the program, SBIR demonstrated materials with MWIR apparent temperatures in excess of 1400 K. New emitter materials have subsequently been selected to produce pixels that achieve even higher apparent temperatures. Test results from pixels fabricated using the new material set will be presented and discussed. A 'scalable' Read In Integrated Circuit (RIIC) is also being developed under the same UHT program to drive the high temperature pixels. This RIIC will utilize through-silicon via (TSV) and Quilt Packaging (QP) technologies to allow seamless tiling of multiple chips to fabricate very large arrays, and thus overcome the yield limitations inherent in large-scale integrated circuits. Results of design verification testing of the completed RIIC will be presented and discussed.

  10. Bacteria-foraging based-control of high-performance railway level-crossing safety drives fed from photovoltaic array

    Directory of Open Access Journals (Sweden)

    Essamudin A. Ebrahim

    2016-12-01

    Full Text Available In the past ten years, railway level-crossing accidents have noticeably escalated in an indisputably preposterous manner, this devastating snag opened the floodgates for the frustrating death of a numerous number of the third world’s citizens, especially in Egypt. To tackle with this problem, a fully intelligent control system is required, which must be automated without human intervention. So, in this research, a new proposed level-crossing tracking system is designed and introduced. The system comprises a high-performance induction motor (IM fed from photovoltaic (PV array, the boom barrier (gate with its mechanism – as a load – buck–boost converter, inverter, and two smart PI-controllers. The first one is designed to regulate the duty cycle of the converter to its optimum value required to balance between maximum power point tracking (MPPT and keeping dc-link voltage of the inverter at a minimum level needed to maintain the motor internal torque at rated value. The second PI-controller is designed for speed control of indirect field-oriented vector-control (IFO-VC IM. The proposed design problems of MPPT, dc-link voltage and speed controllers are solved as optimization problems by bacteria-foraging optimization (BFO algorithm to search for the optimal PI-parameters. The simulation test results are acquired when using the battery-less PV-array with and without the proposed controllers. Also, results are obtained when applying several prescribed speed trajectories to test the robustness against PV-irradiance fluctuations and motor-dynamic disturbances. From these results, the proposed intelligent controllers are robust compared to classical Ziegler–Nichols (ZN PI-controllers and also when the motor is directly fed from PV generator without converter.

  11. Winter distribution and use of high elevation caves as foraging sites by the endangered Hawaiian hoary bat, Lasiurus cinereus semotus

    Science.gov (United States)

    Bonaccorso, Frank; Montoya-Aiona, Kristina; Pinzari, Corinna A.; Todd, Christopher M.

    2016-01-01

    We examine altitudinal movements involving unusual use of caves by Hawaiian hoary bats, Lasiurus cinereus semotus, during winter and spring in the Mauna Loa Forest Reserve (MLFR), Hawai‘i Island. Acoustic detection of hoary bat vocalizations, were recorded with regularity outside 13 lava tube cave entrances situated between 2,200 to 3,600 m asl from November 2012 to April 2013. Vocalizations were most numerous in November and December with the number of call events and echolocation pulses decreasing through the following months. Bat activity was positively correlated with air temperature and negatively correlated with wind speed. Visual searches found no evidence of hibernacula nor do Hawaiian hoary bats appear to shelter by day in these caves. Nevertheless, bats fly deep into caves as evidenced by numerous carcasses found in cave interiors. The occurrence of feeding buzzes around cave entrances and visual observations of bats flying in acrobatic fashion in cave interiors point to the use of these spaces as foraging sites. Peridroma moth species (Noctuidae), the only abundant nocturnal, flying insect sheltering in large numbers in rock rubble and on cave walls in the MLFR, apparently serve as the principal prey attracting hoary bats during winter to lava tube caves in the upper MLFR. Caves above 3,000 m on Mauna Loa harbor temperatures suitable for Pseudogymnoascus destructansfungi, the causative agent of White-nose Syndrome that is highly lethal to some species of North American cave-dwelling bats. We discuss the potential for White-nose Syndrome to establish and affect Hawaiian hoary bats.

  12. Effects of disodium fumarate on ruminal fermentation and microbial communities in sheep fed on high-forage diets.

    Science.gov (United States)

    Zhou, Y W; McSweeney, C S; Wang, J K; Liu, J X

    2012-05-01

    This study was conducted to investigate effects of disodium fumarate (DF) on fermentation characteristics and microbial populations in the rumen of Hu sheep fed on high-forage diets. Two complementary feeding trials were conducted. In Trial 1, six Hu sheep fitted with ruminal cannulae were randomly allocated to a 2 × 2 cross-over design involving dietary treatments of either 0 or 20 g DF daily. Total DNA was extracted from the fluid- and solid-associated rumen microbes, respectively. Numbers of 16S rDNA gene copies associated with rumen methanogens and bacteria, and 18S rDNA gene copies associated with rumen protozoa and fungi were measured using real-time PCR, and expressed as proportion of total rumen bacteria 16S rDNA. Ruminal pH decreased in the DF group compared with the control (P sheep were fed on basal diet for 2 weeks and continuously for 4 weeks with supplementation of DF at a level of 20 g/day. Ruminal samples were collected every week to analyze fermentation parameters and microbial populations. No effects of DF were observed on pH, acetate and butyrate (P > 0.05). Populations of methanogens and R. flavefaciens decreased in the fluid samples (P clone sequences from cut-out bands appearing in both the 2nd and the 4th week were 94% to 100% similar to Prevotella-like bacteria, and four sequences showed 95% to 98% similarity to Selenomonas dianae. Another 15 sequences were obtained from bands, which appeared in the 4th week only. Thirteen of these 15 sequences showed 95% to 99% similarity to Clostridium sp., and the other two showed 95% and 100% similarity to Ruminococcus sp. In summary, the microorganisms positively responding to DF addition were the cellulolytic bacteria, R. albus, F. succinogenes and B. fibrisolvens as well as proteolytic bacteria, B. fibrisolvens, P. ruminicola and Clostridium sp.

  13. Comparison of the Level of Using Metacognitive Strategies during Study between High Achieving and Low Achieving Prospective Teachers

    Science.gov (United States)

    Doganay, Ahmet; Demir, Ozden

    2011-01-01

    The main purpose of this study is to compare the level of using metacognitive strategies during study between high achieving and low achieving prospective classroom teachers. This study was designed as a mixed method study. Metacognitive Learning Strategies Scale developed by Namlu (2004) was used to measure the use of metacognitive strategies…

  14. Parent Child Relationship Among High and Low Achieving High School Students

    Directory of Open Access Journals (Sweden)

    Dr. Satish Kumar Kalhotra

    2013-12-01

    Full Text Available The present study was carried out to identify Parent Child Relationship Among High and Low Achieving High School Students. A sample of 151 students of IX class students of Govt. school were selected from stratified random sampling. Rao’s (1989 parent-child relationship scale were used to assess the parental relationship The statistical technique like mean, median critical ration was used to find the low and high achiever relationship between father-child & mother child relationship. Lamsal inventory was used to collected the data.The results reveals that High achievers are loved more by their fathers than low ones and are given due importance at home. In constant the mothers equally love both high and low achievers.

  15. Precision-feeding dairy heifers a high rumen-degradable protein diet with different proportions of dietary fiber and forage-to-concentrate ratios.

    Science.gov (United States)

    Lascano, G J; Koch, L E; Heinrichs, A J

    2016-09-01

    The objective of this experiment was to determine the effects of feeding a high-rumen-degradable protein (RDP) diet when dietary fiber content is manipulated within differing forage-to-concentrate ratio (F:C) on nutrient utilization of precision-fed dairy heifers. Six cannulated Holstein heifers (486.98±15.07kg of body weight) were randomly assigned to 2 F:C, low- (45% forage; LF) and high-forage (90% forage; HF) diets and to a fiber proportion sequence [33% grass hay and wheat straw (HS), 67% corn silage (CS; low fiber); 50% HS, 50% CS (medium fiber); and 67% HS, 33% CS (high fiber)] within forage proportion administered according to a split-plot, 3×3 Latin square design (16-d periods). Heifers fed LF had greater apparent total-tract organic matter digestibility coefficients (dC), neutral detergent fiber, and cellulose than those fed LC diets. Substituting CS with HS resulted in a linear reduction in dry matter, organic matter, and cellulose dC. Nitrogen dC was not different between F:C or with increasing proportions of HS in diets, but N retention tended to decrease linearly as HS was increased in the diets. Predicted microbial protein flow to the duodenum decreased linearly with HS addition and protozoa numbers HS interacted linearly, exhibiting a decrease as HS increased for LF, whereas no effects were observed for HF. Blood urea N increased linearly as HS was incorporated. The LF-fed heifers had a greater ruminal volatile fatty acids concentration. We noted a tendency for a greater dry matter, and a significantly higher liquid fraction turnover rate for HF diets. There was a linear numerical increase in the liquid and solid fraction turnover rate as fiber was added to the diets. Rumen fermentation parameters and fractional passages (solid and liquid) rates support the reduction in dC, N retention, and microbial protein synthesis observed as more dietary fiber is added to the rations of dairy heifers precision-fed a constant proportion of rumen

  16. High-Achieving High School Students and Not so High-Achieving College Students: A Look at Lack of Self-Control, Academic Ability, and Performance in College

    Science.gov (United States)

    Honken, Nora B.; Ralston, Patricia A. S.

    2013-01-01

    This study investigated the relationship among lack of self-control, academic ability, and academic performance for a cohort of freshman engineering students who were, with a few exceptions, extremely high achievers in high school. Structural equation modeling analysis led to the conclusion that lack of self-control in high school, as measured by…

  17. Learning Styles and High School Students' Chemistry Achievement

    Science.gov (United States)

    Uzuntiryaki, Esen

    2007-01-01

    The aim of the present study was to investigate the effects of students' learning styles on their chemistry achievement, and whether matching between teaching and learning styles also affects students' chemistry achievement. Two hundred and sixty-five tenth-grade students enrolled in a chemistry course and seven chemistry teachers participated in…

  18. Foraging task specialisation and foraging labour allocation in stingless bees

    NARCIS (Netherlands)

    Hofstede, Frouke Elisabeth

    2006-01-01

    Social bees collect nectar and pollen from flowering plants for energy of the adult bees and for feeding the larvae in the colony. The flowering patterns of plants imply that periods of high food availability are often followed by periods of meagre foraging conditions. Being dependent on such a dyna

  19. Foraging Behavior of Odontomachus bauri on Barro Colorado Island, Panama

    Directory of Open Access Journals (Sweden)

    Birgit Ehmer

    1995-01-01

    Full Text Available Foraging behavior and partitioning of foraging areas of Odonomachus bauri were investigated on Barro Colorado Island in Panama. The activity of the ants did not show any daily pattern; foragers were active day and night. The type of prey captured by O. bauri supports the idea that in higher Odontomachus and Anochetus species, the high speed of mandible closure serves more for generating power than capturing elusive prey. Polydomous nests may enable O. bauri colonies to enlarge their foraging areas.

  20. Forage use to improve environmental sustainability of ruminant production.

    Science.gov (United States)

    Guyader, J; Janzen, H H; Kroebel, R; Beauchemin, K A

    2016-08-01

    "best-management" practices that can be recommended everywhere. Using systems-based approaches such as life cycle analysis, ruminant production can be tuned for local lands to achieve greatest net benefits overall. In many instances, such systems, based on forages, may maintain high output of milk and meat while also furnishing other ecosystem benefits, such as reduced overall greenhouse gas emissions.

  1. The Effect of Music Participation on Mathematical Achievement and Overall Academic Achievement of High School Students

    Science.gov (United States)

    Cox, H. A.; Stephens, L. J.

    2006-01-01

    A study was conducted on high school students, comparing those with some music credits to those with none. No statistically significant difference was found in their mean math grade point averages (GPA) or their mean cumulative GPAs. Students were then separated into two groups based on the number of music credits. Students who had earned at least…

  2. The Effect of Music Participation on Mathematical Achievement and Overall Academic Achievement of High School Students

    Science.gov (United States)

    Cox, H. A.; Stephens, L. J.

    2006-01-01

    A study was conducted on high school students, comparing those with some music credits to those with none. No statistically significant difference was found in their mean math grade point averages (GPA) or their mean cumulative GPAs. Students were then separated into two groups based on the number of music credits. Students who had earned at least…

  3. Academic attainment and the high school science experiences among high-achieving African American males

    Science.gov (United States)

    Trice, Rodney Nathaniel

    This study examines the educational experiences of high achieving African American males. More specifically, it analyzes the influences on their successful navigation through high school science. Through a series of interviews, observations, questionnaires, science portfolios, and review of existing data the researcher attempted to obtain a deeper understanding of high achieving African American males and their limitations to academic attainment and high school science experiences. The investigation is limited to ten high achieving African American male science students at Woodcrest High School. Woodcrest is situated at the cross section of a suburban and rural community located in the southeastern section of the United States. Although this investigation involves African American males, all of whom are successful in school, its findings should not be generalized to this nor any other group of students. The research question that guided this study is: What are the limitations to academic attainment and the high school science experiences of high achieving African American males? The student participants expose how suspension and expulsion, special education placement, academic tracking, science instruction, and teacher expectation influence academic achievement. The role parents play, student self-concept, peer relationships, and student learning styles are also analyzed. The anthology of data rendered three overarching themes: (1) unequal access to education, (2) maintenance of unfair educational structures, and (3) authentic characterizations of African American males. Often the policies and practices set in place by school officials aid in creating hurdles to academic achievement. These policies and practices are often formed without meaningful consideration of the unintended consequences that may affect different student populations, particularly the most vulnerable. The findings from this study expose that high achieving African American males face major

  4. Parenting Style, Perfectionism, and Creativity in High-Ability and High-Achieving Young Adults

    Science.gov (United States)

    Miller, Angie L.; Lambert, Amber D.; Speirs Neumeister, Kristie L.

    2012-01-01

    The current study explores the potential relationships among perceived parenting style, perfectionism, and creativity in a high-ability and high-achieving young adult population. Using data from 323 honors college students at a Midwestern university, bivariate correlations suggested positive relationships between (a) permissive parenting style and…

  5. Parenting Style, Perfectionism, and Creativity in High-Ability and High-Achieving Young Adults

    Science.gov (United States)

    Miller, Angie L.; Lambert, Amber D.; Speirs Neumeister, Kristie L.

    2012-01-01

    The current study explores the potential relationships among perceived parenting style, perfectionism, and creativity in a high-ability and high-achieving young adult population. Using data from 323 honors college students at a Midwestern university, bivariate correlations suggested positive relationships between (a) permissive parenting style and…

  6. Success Despite Socioeconomics: A Case Study of a High-Achieving, High-Poverty School

    Science.gov (United States)

    Tilley, Thomas Brent; Smith, Samuel J.; Claxton, Russell L.

    2012-01-01

    This case study of a high-achieving, high-poverty school describes the school's leadership, culture, and programs that contributed to its success. Data were collected from two surveys (the School Culture Survey and the Vanderbilt Assessment of Leadership in Education), observations at the school site, and interviews with school personnel. The…

  7. Maize forage aptitude: Combining ability of inbred lines and stability of hybrids

    Directory of Open Access Journals (Sweden)

    Luis Máximo Bertoia

    2014-12-01

    Full Text Available Breeding of forage maize should combine improvement achieved for grain with the specific needs of forage hybrids. Production stability is important when maize is used for silage if the planting area is not in the ideal agronomic environment. The objectives of the present research were: (i to quantify environmental and genetic and their interaction effects on maize silage traits; (ii to identify possible heterotic groups for forage aptitude and suggest the formation of potential heterotic patterns, and (iii to identify suitable inbred line combinations for producing hybrids with forage aptitude. Forty-five hybrids derived from diallelic crosses (without reciprocals among ten inbred lines of maize were evaluated in this study. Combined ANOVA over environments showed differences between genotypes (G, environments (E, and their interactions (GEI. Heritability (H2, and genotypic and phenotypic correlations were estimated to evaluate the variation in and relationships between forage traits. Postdictive and predictive AMMI models were fitted to determine the importance of each source of variation, G, E, and GEI, and to select genotypes simultaneously on yield, quality and stability. A predominance of additive effects was found in the evaluated traits. The heterotic pattern Reid-BSSS × Argentine flint was confirmed for ear yield (EY and harvest index (HI. High and broad genetic variation was found for stover and whole plant traits. Some inbred lines had genes with differential breeding aptitude for ear and stover. Stover and ear yield should be the main breeding objectives in maize forage breeding.

  8. Maize forage aptitude: Combining ability of inbred lines and stability of hybrids

    Institute of Scientific and Technical Information of China (English)

    Luis; Máximo; Bertoia; Mónica; Beatriz; Aulicino

    2014-01-01

    Breeding of forage maize should combine improvement achieved for grain with the specific needs of forage hybrids. Production stability is important when maize is used for silage if the planting area is not in the ideal agronomic environment. The objectives of the present research were:(i) to quantify environmental and genetic and their interaction effects on maize silage traits;(ii) to identify possible heterotic groups for forage aptitude and suggest the formation of potential heterotic patterns, and(iii) to identify suitable inbred line combinations for producing hybrids with forage aptitude. Forty-five hybrids derived from diallelic crosses(without reciprocals) among ten inbred lines of maize were evaluated in this study. Combined ANOVA over environments showed differences between genotypes(G), environments(E), and their interactions(GEI). Heritability(H2), and genotypic and phenotypic correlations were estimated to evaluate the variation in and relationships between forage traits. Postdictive and predictive AMMI models were fitted to determine the importance of each source of variation, G, E, and GEI, and to select genotypes simultaneously on yield, quality and stability. A predominance of additive effects was found in the evaluated traits. The heterotic pattern Reid-BSSS × Argentine flint was confirmed for ear yield(EY) and harvest index(HI). High and broad genetic variation was found for stover and whole plant traits. Some inbred lines had genes with differential breeding aptitude for ear and stover. Stover and ear yield should be the main breeding objectives in maize forage breeding.

  9. "Brains before "Beauty"?" High Achieving Girls, School and Gender Identities

    Science.gov (United States)

    Skelton, Christine; Francis, Becky; Read, Barbara

    2010-01-01

    In recent years educational policy on gender and achievement has concentrated on boys' underachievement, frequently comparing it with the academic success of girls. This has encouraged a perception of girls as the "winners" of the educational stakes and assumes that they no longer experience the kinds of gender inequalities identified in…

  10. "Brains before "Beauty"?" High Achieving Girls, School and Gender Identities

    Science.gov (United States)

    Skelton, Christine; Francis, Becky; Read, Barbara

    2010-01-01

    In recent years educational policy on gender and achievement has concentrated on boys' underachievement, frequently comparing it with the academic success of girls. This has encouraged a perception of girls as the "winners" of the educational stakes and assumes that they no longer experience the kinds of gender inequalities identified in earlier…

  11. Dominant Achievement Goals across Tracks in High School

    Science.gov (United States)

    Scheltinga, Peter A. M.; Kuyper, Hans; Timmermans, Anneke C.; van der Werf, Greetje P. C.

    2016-01-01

    The dominant achievement goals (DAGs) of 7,008 students in the third grade of Dutch secondary education (US grade 9) were investigated, based on Elliot & McGregors' 2 × 2 framework (2001), in relation to track-level and motivational variables. We found the mastery-approach goal and the performance-approach goal, generally considered adaptive,…

  12. Utilisation of intensive foraging zones by female Australian fur seals.

    Directory of Open Access Journals (Sweden)

    Andrew J Hoskins

    Full Text Available Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search. For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity 'hot spots' were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a

  13. Utilisation of intensive foraging zones by female Australian fur seals.

    Science.gov (United States)

    Hoskins, Andrew J; Costa, Daniel P; Arnould, John P Y

    2015-01-01

    Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search). For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour) determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity 'hot spots' were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a foraging patch.

  14. Utilisation of Intensive Foraging Zones by Female Australian Fur Seals

    Science.gov (United States)

    Hoskins, Andrew J.; Costa, Daniel P.; Arnould, John P. Y.

    2015-01-01

    Within a heterogeneous environment, animals must efficiently locate and utilise foraging patches. One way animals can achieve this is by increasing residency times in areas where foraging success is highest (area-restricted search). For air-breathing diving predators, increased patch residency times can be achieved by altering both surface movements and diving patterns. The current study aimed to spatially identify the areas where female Australian fur seals allocated the most foraging effort, while simultaneously determining the behavioural changes that occur when they increase their foraging intensity. To achieve this, foraging behaviour was successfully recorded with a FastLoc GPS logger and dive behaviour recorder from 29 individual females provisioning pups. Females travelled an average of 118 ± 50 km from their colony during foraging trips that lasted 7.3 ± 3.4 days. Comparison of two methods for calculating foraging intensity (first-passage time and first-passage time modified to include diving behaviour) determined that, due to extended surface intervals where individuals did not travel, inclusion of diving behaviour into foraging analyses was important for this species. Foraging intensity ‘hot spots’ were found to exist in a mosaic of patches within the Bass Basin, primarily to the south-west of the colony. However, the composition of benthic habitat being targeted remains unclear. When increasing their foraging intensity, individuals tended to perform dives around 148 s or greater, with descent/ascent rates of approximately 1.9 m•s-1 or greater and reduced postdive durations. This suggests individuals were maximising their time within the benthic foraging zone. Furthermore, individuals increased tortuosity and decreased travel speeds while at the surface to maximise their time within a foraging location. These results suggest Australian fur seals will modify both surface movements and diving behaviour to maximise their time within a foraging patch

  15. Achieving Timeliness and High Throughput Metrics in Dissemination Systems

    Directory of Open Access Journals (Sweden)

    MANNE ANUSHA

    2012-09-01

    Full Text Available Existing systems for information dissemination is inadequate and typically results in information gaps. The lack of a clear concise system for information dissemination makes it difficult to determine the most efficient and effective way to pass information especially in the fields of ecommerce and security alerting systems to the appropriate parties. These systems usually require that the desired information be matched between numerous sources and sinks based on established subscriptions. Timeliness and Throughput are performance metrics used for evaluation. And these existing systems fail to achieve a balance between the two. So a much better system termed INFOD (INFOrmation Dissemination was proposed earlier that achieves a balance between performance metrics. We observed that an Integrated Control Loop used by admission control scheme of INFOD employs PL/SQL stored procedures that are huge computation overhead. We propose to replace them with Java stored procedures that can tremendously increase the performance.

  16. Ruminal fermentation of Anti-methanogenic Nitrate- and Nitro-Containing Forages In Vitro

    Directory of Open Access Journals (Sweden)

    Robin C. Anderson

    2016-08-01

    Full Text Available Nitrate, 3-nitro-1-propionic acid (NPA and 3-nitro-1-propanol (NPOH can accumulate in forages and be poisonous to animals if consumed in high enough amounts. These chemicals are also recognized as potent anti-methanogenic compounds, but plants naturally containing these chemicals have been studied little in this regard. Presently, we found that nitrate-, NPA- or NPOH-containing forages effectively decreased methane production, by 35 to 87%, during in vitro fermentation by mixed cultures of ruminal microbes compared to fermentation by cultures incubated similarly with alfalfa. Methane production was further decreased during incubation of mixed cultures also inoculated with Denitrobacterium detoxificans, a ruminal bacterium known to metabolize nitrate, NPA and NPOH. Inhibition of methanogens within the mixed cultures was greatest with the NPA- and NPOH-containing forages. Hydrogen accumulated in all the mixed cultures incubated with forages containing nitrate, NPA or NPOH but was dramatically higher, exceeding 40 µmol hydrogen/mL, in mixed cultures incubated with NPA-containing forage but not inoculated with D. detoxificans. This possibly reflects the inhibition of hydrogenase-catalyzed uptake of hydrogen produced via conversion of 50 µmol added formate per mL to hydrogen. Accumulations of volatile fatty acids revealed compensatory changes in fermentation in mixed cultures incubated with the nitrate-, NPA- and NPOH-containing forages as evidenced by lower accumulations of acetate, and in some cases higher accumulations of butyrate and lower accumulations of ammonia, iso-buytrate and iso-valerate compared to cultures incubated with alfalfa. Results reveal that nitrate, NPA and NPOH that accumulate naturally in forages can be made available within ruminal incubations to inhibit methanogenesis. Further research is warranted to determine if diets can be formulated with nitrate-, NPA- and NPOH-containing forages to achieve efficacious mitigation in

  17. Ruminal Fermentation of Anti-Methanogenic Nitrate- and Nitro-Containing Forages In Vitro

    Science.gov (United States)

    Anderson, Robin C.; Ripley, Laura H.; Bowman, Jan G. P.; Callaway, Todd R.; Genovese, Kenneth J.; Beier, Ross C.; Harvey, Roger B.; Nisbet, David J.

    2016-01-01

    Nitrate, 3-nitro-1-propionic acid (NPA) and 3-nitro-1-propanol (NPOH) can accumulate in forages and be poisonous to animals if consumed in high enough amounts. These chemicals are also recognized as potent anti-methanogenic compounds, but plants naturally containing these chemicals have been studied little in this regard. Presently, we found that nitrate-, NPA-, or NPOH-containing forages effectively decreased methane production, by 35–87%, during in vitro fermentation by mixed cultures of ruminal microbes compared to fermentation by cultures incubated similarly with alfalfa. Methane production was further decreased during the incubation of mixed cultures also inoculated with Denitrobacterium detoxificans, a ruminal bacterium known to metabolize nitrate, NPA, and NPOH. Inhibition of methanogens within the mixed cultures was greatest with the NPA- and NPOH-containing forages. Hydrogen accumulated in all the mixed cultures incubated with forages containing nitrate, NPA or NPOH and was dramatically higher, exceeding 40 μmol hydrogen/mL, in mixed cultures incubated with NPA-containing forage but not inoculated with D. detoxificans. This possibly reflects the inhibition of hydrogenase-catalyzed uptake of hydrogen produced via conversion of 50 μmol added formate per milliliter to hydrogen. Accumulations of volatile fatty acids revealed compensatory changes in fermentation in mixed cultures incubated with the nitrate-, NPA-, and NPOH-containing forages as evidenced by lower accumulations of acetate, and in some cases, higher accumulations of butyrate and lower accumulations of ammonia, iso-buytrate, and iso-valerate compared to cultures incubated with alfalfa. Results reveal that nitrate, NPA, and NPOH that accumulate naturally in forages can be made available within ruminal incubations to inhibit methanogenesis. Further research is warranted to determine if diets can be formulated with nitrate-, NPA-, and NPOH-containing forages to achieve efficacious mitigation

  18. Absence of vancomycin-resistant enterococci among highly ESBL-positive crows (Corvus splendens foraging on hospital waste in Bangladesh

    Directory of Open Access Journals (Sweden)

    Badrul Hasan

    2015-12-01

    Full Text Available Background: Vancomycin-resistant enterococci (VRE have emerged as a growing problem in hospitals; however, domesticated animals, poultry, and wild birds are acting as potential reservoirs. There is a knowledge gap in the Epidemiology of VRE from Bangladesh. Methods: To study the prevalence of VRE and the mechanisms of resistance implicated among wild birds, 238 fecal samples were collected in 2010 from house crows (Corvus splendens foraging on hospital waste in Bangladesh. Fecal samples were screened by analyzing color change in broth and screening for vanA and vanB resistant genes by PCR. Results: Neither vanA nor vanB genes were detected from the fecal samples. The house crow does not seem to constitute a reservoir for VRE. Conclusion: The zero prevalence is an indication that foraging on hospital waste does not constitute a major risk of VRE carriage in house crows and this is the first study to focus on the prevalence of VRE from wild birds in Bangladesh.

  19. The Information Search Process of High-, Middle-, and Low-Achieving High School Seniors.

    Science.gov (United States)

    Kuhlthau, Carol C.

    1989-01-01

    Presents a model of the information search process as a complex series of stages involving thoughts and feelings as well as actions. A study that sought to verify the model using high school seniors from three different achievement levels is described, and the implications for library instruction are discussed. (five references) (CLB)

  20. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  1. Practically Perfect in Every Way: Can Reframing Perfectionism for High-Achieving Undergraduates Impact Academic Resilience?

    Science.gov (United States)

    Dickinson, Mary J.; Dickinson, David A. G.

    2015-01-01

    This study focuses on a pan-disciplinary scheme that targeted high-achieving undergraduate students. Earlier research from the scheme argued that high achievers have discernibly different learning and personal development support needs. One of the most frequent self-reported challenges within this high-achieving group is perfectionism. This…

  2. Modeling ventilation time in forage tower silos.

    Science.gov (United States)

    Bahloul, A; Chavez, M; Reggio, M; Roberge, B; Goyer, N

    2012-10-01

    The fermentation process in forage tower silos produces a significant amount of gases, which can easily reach dangerous concentrations and constitute a hazard for silo operators. To maintain a non-toxic environment, silo ventilation is applied. Literature reviews show that the fermentation gases reach high concentrations in the headspace of a silo and flow down the silo from the chute door to the feed room. In this article, a detailed parametric analysis of forced ventilation scenarios built via numerical simulation was performed. The methodology is based on the solution of the Navier-Stokes equations, coupled with transport equations for the gas concentrations. Validation was achieved by comparing the numerical results with experimental data obtained from a scale model silo using the tracer gas testing method for O2 and CO2 concentrations. Good agreement was found between the experimental and numerical results. The set of numerical simulations made it possible to establish a simple analytical model to predict the minimum time required to ventilate a silo to make it safe to enter. This ventilation time takes into account the headspace above the forage, the airflow rate, and the initial concentrations of O2 and CO2. The final analytical model was validated with available results from the literature.

  3. Academic achievement of junior high school students with sleep disorders

    National Research Council Canada - National Science Library

    Auliyanti, Fijri; Sekartini, Rini; Mangunatmadja, Irawan

    2016-01-01

    ... status, family structure, after-hours education program, presence of TV/computer in the bedroom, sleep duration during school days, as well as bedtime and wakeup time difference in junior high school...

  4. Application of stable isotope analysis to study temporal changes in foraging ecology in a highly endangered amphibian.

    Directory of Open Access Journals (Sweden)

    J Hayley Gillespie

    Full Text Available BACKGROUND: Understanding dietary trends for endangered species may be essential to assessing the effects of ecological disturbances such as habitat modification, species introductions or global climate change. Documenting temporal variation in prey selection may also be crucial for understanding population dynamics. However, the rarity, secretive behaviours and obscure microhabitats of some endangered species can make direct foraging observations difficult or impossible. Furthermore, the lethality or invasiveness of some traditional methods of dietary analysis (e.g. gut contents analysis, gastric lavage makes them inappropriate for such species. Stable isotope analysis facilitates non-lethal, indirect analysis of animal diet that has unrealized potential in the conservation of endangered organisms, particularly amphibians. METHODOLOGY/FINDINGS: I determined proportional contributions of aquatic macroinvertebrate prey to the diet of an endangered aquatic salamander Eurycea sosorum over a two-year period using stable isotope analysis of (13/12C and (15/14N and the Bayesian stable isotope mixing model SIAR. I calculated Strauss' dietary electivity indices by comparing these proportions with changing relative abundance of potential prey species through time. Stable isotope analyses revealed that a previously unknown prey item (soft-bodied planarian flatworms in the genus Dugesia made up the majority of E. sosorum diet. Results also demonstrate that E. sosorum is an opportunistic forager capable of diet switching to include a greater proportion of alternative prey when Dugesia populations decline. There is also evidence of intra-population dietary variation. CONCLUSIONS/SIGNIFICANCE: Effective application of stable isotope analysis can help circumvent two key limitations commonly experienced by researchers of endangered species: the inability to directly observe these species in nature and the invasiveness or lethality of traditional methods of

  5. Environmental conditions and crop density as the limiting factors of forage maize production

    Directory of Open Access Journals (Sweden)

    Dragičević Vesna D.

    2016-01-01

    Full Text Available In rain-fed cropping, defining the best combination of practices could achieve high forage yield and silage quality. The aim of this study was to compare energetic quality of produced silage with productive characteristics of forage maize cultivated on alluvium and hydromorphous black soil in rain-fed conditions at four plant densities (68-74,000 plants ha-1 during the period 2005- 2010. Yield and energy parameters were increased to some extent at higher crop densities indicating that higher densities (74,000 plants ha-1 were potentially better for high forage and DM yields, while lower densities (70,000 plants ha-1 were better for the increase of energy parameters of produced silage. [Projekat Ministarstva nauke Republike Srbije, br. TR-31037

  6. Gender, Student Motivation and Academic Achievement in a Midsized Wisconsin High School

    Science.gov (United States)

    Lutzke, Steven Ronald

    2013-01-01

    This mixed-methods study investigated relationships among gender, academic motivation and achievement in a mid-sized Wisconsin high school. A questionnaire was developed that focused on perceived ability, achievement motives and achievement goals. Interviews with teachers focused on relationships among academic motivation and gender achievement.…

  7. Scavenger: Transparent Development of Efficient Cyber Foraging Applications

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø

    2010-01-01

    Cyber foraging is a pervasive computing technique where small mobile devices offload resource intensive tasks to stronger computing machinery in the vicinity. This paper presents Scavenger-a new cyber foraging system supporting easy development of mobile cyber foraging applications, while still...... delivering efficient, mobile use of remote computing resources through the use of a custom built mobile code execution environment and a new dual-profiling scheduler. One of the main difficulties within cyber foraging is that it is very challenging for application programmers to develop cyber foraging...... enabled applications. An application using cyber foraging is working with mobile, distributed and, possibly, parallel computing; fields within computer science known to be hard for programmers to grasp. In this paper it is shown by example, how a highly distributed, parallel, cyber foraging enabled...

  8. Impact of learning orientation on African American children's attitudes toward high-achieving peers.

    Science.gov (United States)

    Marryshow, Derrick; Hurley, Eric A; Allen, Brenda A; Tyler, Kenneth M; Boykin, A Wade

    2005-01-01

    This study examined Ogbu's widely accepted thesis that African American students reject high academic achievement because they perceive its limited utility in a world where their upward mobility is constrained by racial discrimination. Boykin's psychosocial integrity model contends that Black students value high achievement but that discrepancies between their formative cultural experiences and those imposed in school lead them to reject the modes of achievement available in classrooms. Ninety Black children completed a measure of attitudes toward students who achieve via mainstream or African American cultural values. Participants rejected the mainstream achievers and embraced the African American cultural achievers. Moreover, they expected their teachers to embrace the mainstream achievers and reject those who achieved through high-verve behavior. Results suggest that Boykin's thesis is a needed refinement to Ogbu's ideas. They indicate that Black children may reject not high achievement but some of the mainstream cultural values and behaviors on which success in mainstream classrooms is made contingent.

  9. Achieving Mixtures of Ultra-High Performance Concrete

    Directory of Open Access Journals (Sweden)

    Mircea POPA

    2013-07-01

    Full Text Available Ultra-High Performance Concrete (UHPC is a relatively new concrete. According to [11] UHPC is that concrete which features compressive strength over C100/115 class. Up to this point standards for this type of concrete were not adopted, although its characteristic strength exceeds those specified in [33]. Its main property is high compressive strength. This provides the possibility of reducing the section of elements (beams or columns made of this type of concrete, while the load capacity remains high. The study consists in blending mixtures of UHPC made of varying proportions of materials. The authors have obtained strengths of up to 160 MPa. The materials used are: Portland cement, silica fume, quartz powder, steel fibers, superplasticiser, sand and crushed aggregate for concrete - andesite.

  10. Testing Theories of Learning: Effects on High School Achievement.

    Science.gov (United States)

    Keith, Timothy Z.; Cool, Valerie A.

    Theories of school learning consistently point to variables such as ability, time (e.g., homework), quality of instruction, motivation, and academic coursework as important influences on learning. In this study, path analysis was used to test the direct and indirect effects of these variables on high school learning, with learning measured by both…

  11. Academic Dishonesty among Gifted and High-Achieving Students

    Science.gov (United States)

    Geddes, Kimberly A.

    2011-01-01

    Gifted high school students are essentially absent in the research concerning academic integrity; however, over the past few years, educators of gifted students have noticed an increase in the occurrences of academic dishonesty among students in gifted classrooms (Abilock, 2009). This research may be analyzed to provide some insight into the…

  12. Academic Dishonesty among Gifted and High-Achieving Students

    Science.gov (United States)

    Geddes, Kimberly A.

    2011-01-01

    Gifted high school students are essentially absent in the research concerning academic integrity; however, over the past few years, educators of gifted students have noticed an increase in the occurrences of academic dishonesty among students in gifted classrooms (Abilock, 2009). This research may be analyzed to provide some insight into the…

  13. Learning Disabilities and Achieving High-Quality Education Standards

    Science.gov (United States)

    Gartland, Debi; Strosnider, Roberta

    2017-01-01

    This is an official document of the National Joint Committee on Learning Disabilities (NJCLD), of which Council for Learning Disabilities is a long-standing, active member. With this position paper, NJCLD advocates for the implementation of high-quality education standards (HQES) for students with learning disabilities (LD) and outlines the…

  14. Achieving High Reliability Operations Through Multi-Program Integration

    Energy Technology Data Exchange (ETDEWEB)

    Holly M. Ashley; Ronald K. Farris; Robert E. Richards

    2009-04-01

    Over the last 20 years the Idaho National Laboratory (INL) has adopted a number of operations and safety-related programs which has each periodically taken its turn in the limelight. As new programs have come along there has been natural competition for resources, focus and commitment. In the last few years, the INL has made real progress in integrating all these programs and are starting to realize important synergies. Contributing to this integration are both collaborative individuals and an emerging shared vision and goal of the INL fully maturing in its high reliability operations. This goal is so powerful because the concept of high reliability operations (and the resulting organizations) is a masterful amalgam and orchestrator of the best of all the participating programs (i.e. conduct of operations, behavior based safety, human performance, voluntary protection, quality assurance, and integrated safety management). This paper is a brief recounting of the lessons learned, thus far, at the INL in bringing previously competing programs into harmony under the goal (umbrella) of seeking to perform regularly as a high reliability organization. In addition to a brief diagram-illustrated historical review, the authors will share the INL’s primary successes (things already effectively stopped or started) and the gaps yet to be bridged.

  15. Telescoping Solar Array Concept for Achieving High Packaging Efficiency

    Science.gov (United States)

    Mikulas, Martin; Pappa, Richard; Warren, Jay; Rose, Geoff

    2015-01-01

    Lightweight, high-efficiency solar arrays are required for future deep space missions using high-power Solar Electric Propulsion (SEP). Structural performance metrics for state-of-the art 30-50 kW flexible blanket arrays recently demonstrated in ground tests are approximately 40 kW/cu m packaging efficiency, 150 W/kg specific power, 0.1 Hz deployed stiffness, and 0.2 g deployed strength. Much larger arrays with up to a megawatt or more of power and improved packaging and specific power are of interest to mission planners for minimizing launch and life cycle costs of Mars exploration. A new concept referred to as the Compact Telescoping Array (CTA) with 60 kW/cu m packaging efficiency at 1 MW of power is described herein. Performance metrics as a function of array size and corresponding power level are derived analytically and validated by finite element analysis. Feasible CTA packaging and deployment approaches are also described. The CTA was developed, in part, to serve as a NASA reference solar array concept against which other proposed designs of 50-1000 kW arrays for future high-power SEP missions could be compared.

  16. High Achievement in Mathematics Education in India: A Report from Mumbai

    Science.gov (United States)

    Raman, Manya

    2010-01-01

    This paper reports a study aimed at characterizing the conditions that lead to high achievement in mathematics in India. The study involved eight schools in the greater Mumbai region. The main result of the study is that the notion of high achievement itself is problematic, as reflected in the reports about mathematics achievement within and…

  17. International note: between-domain relations of Chinese high school students' academic achievements.

    Science.gov (United States)

    Yangyang, Liu

    2012-08-01

    The present study examined the between-domain relations of Chinese high school students' academic achievements. In a sample of 1870 Chinese 10th grade students, the results indicated that Chinese high school students' academic achievements were correlated across nine subjects. In line with the previous Western findings, the findings suggested that academic achievement was largely domain-general in nature.

  18. Co-evolution of learning complexity and social foraging strategies.

    Science.gov (United States)

    Arbilly, Michal; Motro, Uzi; Feldman, Marcus W; Lotem, Arnon

    2010-12-21

    Variation in learning abilities within populations suggests that complex learning may not necessarily be more adaptive than simple learning. Yet, the high cost of complex learning cannot fully explain this variation without some understanding of why complex learning is too costly for some individuals but not for others. Here we propose that different social foraging strategies can favor different learning strategies (that learn the environment with high or low resolution), thereby maintaining variable learning abilities within populations. Using a genetic algorithm in an agent-based evolutionary simulation of a social foraging game (the producer-scrounger game) we demonstrate how an association evolves between a strategy based on independent search for food (playing a producer) and a complex (high resolution) learning rule, while a strategy that combines independent search and following others (playing a scrounger) evolves an association with a simple (low resolution) learning rule. The reason for these associations is that for complex learning to have an advantage, a large number of learning steps, normally not achieved by scroungers, are necessary. These results offer a general explanation for persistent variation in cognitive abilities that is based on co-evolution of learning rules and social foraging strategies.

  19. Feeding of wheat bran and sugar beet pulp as sole supplements in high-forage diets emphasizes the potential of dairy cattle for human food supply.

    Science.gov (United States)

    Ertl, P; Zebeli, Q; Zollitsch, W; Knaus, W

    2016-02-01

    Besides the widely discussed negative environmental effects of dairy production, such as greenhouse gas emissions, the feeding of large amounts of potentially human-edible feedstuffs to dairy cows is another important sustainability concern. The aim of this study was therefore to investigate the effects of a complete substitution of common cereal grains and pulses with a mixture of wheat bran and sugar beet pulp in a high-forage diet on cow performance, production efficiency, feed intake, and ruminating behavior, as well as on net food production potential. Thirteen multiparous and 7 primiparous mid-lactation Holstein dairy cows were randomly assigned to 1 of 2 treatments in a change-over design with 7-wk periods. Cows were fed a high-forage diet (grass silage and hay accounted for 75% of the dry matter intake), supplemented with either a cereal grain-based concentrate mixture (CON), or a mixture of wheat bran and dried sugar beet pulp (WBBP). Human-edible inputs were calculated for 2 different scenarios based on minimum and maximum potential recovery rates of human-edible energy and protein from the respective feedstuffs. Dietary starch and neutral detergent fiber contents were 3.0 and 44.1% for WBBP, compared with 10.8 and 38.2% in CON, respectively. Dietary treatment did not affect milk production, milk composition, feed intake, or total chewing activity. However, chewing index expressed in minutes per kilogram of neutral detergent fiber ingested was 12% lower in WBBP compared with CON. In comparison to CON, the human-edible feed conversion efficiencies for energy and protein, defined as human-edible output per human-edible input, were 6.8 and 5.3 times higher, respectively, in WBBP under the maximum scenario. For the maximum scenario, the daily net food production (human-edible output minus human-edible input) increased from 5.4 MJ and 250 g of crude protein per cow in CON to 61.5 MJ and 630 g of crude protein in the WBBP diet. In conclusion, our data suggest

  20. Rectangular Dielectric-loaded Structures for Achieving High Acceleration Gradients

    Science.gov (United States)

    Wang, Changbiao; Yakovlev, V. P.; Marshall, T. C.; LaPointe, M. A.; Hirshfield, J. L.

    2006-11-01

    Rectangular dielectric-loaded structures are described that may sustain higher acceleration gradients than conventional all-metal structures with similar apertures. One structure is a test cavity designed to ascertain the breakdown limits of dielectrics, while a second structure could be the basis for a two-beam accelerator. CVD diamond is an attractive dielectric for a high-gradient structure, since the published DC breakdown limit for CVD diamond is ˜ 2 GV/m, although the limit has never been determined for RF fields. Here we present a design of a diamond-lined test cavity to measure the breakdown limit. The designed cavity operates at 34 GHz, where with 10-MW input power it is expected to produce an ˜800 MV/m field on the diamond surface—provided breakdown is avoided. The two channel rectangular dielectric-loaded waveguide could be a two-beam accelerator structure, in which a drive beam is in one channel and an accelerated beam is in the other. The RF power produced by drive bunches in the drive channel is continuously coupled to the acceleration channel. The ratio of fields in the channels (transformer ratio) for the operating mode can be designed by adjusting the dimensions of the structure. An example of the two-channel structure is described, in which a train of five 3-nC drive bunches excites wake fields in the accelerator channel of up to 1.3 GV/m with a transformer ratio of 10 for the design mode.

  1. Achieving High-Frequency Optical Control of Synaptic Transmission

    Science.gov (United States)

    Jackman, Skyler L.; Beneduce, Brandon M.; Drew, Iain R.

    2014-01-01

    The optogenetic tool channelrhodopsin-2 (ChR2) is widely used to excite neurons to study neural circuits. Previous optogenetic studies of synapses suggest that light-evoked synaptic responses often exhibit artificial synaptic depression, which has been attributed to either the inability of ChR2 to reliably fire presynaptic axons or to ChR2 elevating the probability of release by depolarizing presynaptic boutons. Here, we compare light-evoked and electrically evoked synaptic responses for high-frequency stimulation at three synapses in the mouse brain. At synapses from Purkinje cells to deep cerebellar nuclei neurons (PC→DCN), light- and electrically evoked synaptic currents were remarkably similar for ChR2 expressed transgenically or with adeno-associated virus (AAV) expression vectors. For hippocampal CA3→CA1 synapses, AAV expression vectors of serotype 1, 5, and 8 led to light-evoked synaptic currents that depressed much more than electrically evoked currents, even though ChR2 could fire axons reliably at up to 50 Hz. The disparity between optical and electrical stimulation was eliminated when ChR2 was expressed transgenically or with AAV9. For cerebellar granule cell to stellate cell (grc→SC) synapses, AAV1 also led to artificial synaptic depression and AAV9 provided superior performance. Artificial synaptic depression also occurred when stimulating over presynaptic boutons, rather than axons, at CA3→CA1 synapses, but not at PC→DCN synapses. These findings indicate that ChR2 expression methods and light stimulation techniques influence synaptic responses in a neuron-specific manner. They also identify pitfalls associated with using ChR2 to study synapses and suggest an approach that allows optogenetics to be applied in a manner that helps to avoid potential complications. PMID:24872574

  2. Foraging Experiences with Children

    Science.gov (United States)

    Russell, Helen Ross

    1976-01-01

    Provided are foraging experiences and wild foods information for utilization in the urban school curriculum. Food uses are detailed for roses, dandelions, wild onions, acorns, cattails, violets and mints. (BT)

  3. COMPARATIVE PERSPECTIVES OF STUDY STRATEGIES AMONG HIGH AND LOW ACHIEVERS DISTANCE LEARNING STUDENTS

    Directory of Open Access Journals (Sweden)

    Muhammad Imran YOUSUF

    2009-07-01

    Full Text Available The main aim of this research is to better understand and draw perceptions of low and high achiever distance learners about their study patterns. The study indicates the areas where significant difference is found among low and high achievers of Allama Iqbal Open University, Pakistan through a self developed questionnaire covering their preferred study location, study times, number of hours spent on study, the difficulties affecting their study patterns and the organization of study strategies in comparative perspective. Greater difficulties were being faced by low achievers in their study. Increased difficulties were encountered by low achievers with study material, volume of study, self-motivation and other factors. There was no significant difference between low and high achievers for their study strategies of studying materials without taking notes and reading aloud. Greater low achievers attempted easy portions of their study material first and took notes simultaneously as compared to high achievers.

  4. What Makes High-Achiever Students Hard to Improve Their Speaking Skill?

    OpenAIRE

    Irmawati, Dini Kurnia

    2016-01-01

    Speaking problems do not only happen to low achiever students. High-achiever students with high average score (above 90) also still have speaking problems. This makes the researcher find it important to investigate what factors that make them still get difficulties in speaking. This research is a descriptive study. The subjects include 9 high-achiever students majoring in English Department that have been selected from University of Brawijaya, State University of Malang, and Kanjuruhan Univer...

  5. The Chinese High School Student's Stress in the School and Academic Achievement

    Science.gov (United States)

    Liu, Yangyang; Lu, Zuhong

    2011-01-01

    In a sample of 466 Chinese high school students, we examined the relationships between Chinese high school students' stress in the school and their academic achievements. Regression mixture modelling identified two different classes of the effects of Chinese high school students' stress on their academic achievements. One class contained 87% of…

  6. The Chinese High School Student's Stress in the School and Academic Achievement

    Science.gov (United States)

    Liu, Yangyang; Lu, Zuhong

    2011-01-01

    In a sample of 466 Chinese high school students, we examined the relationships between Chinese high school students' stress in the school and their academic achievements. Regression mixture modelling identified two different classes of the effects of Chinese high school students' stress on their academic achievements. One class contained 87% of…

  7. Fishing amplifies forage fish population collapses.

    Science.gov (United States)

    Essington, Timothy E; Moriarty, Pamela E; Froehlich, Halley E; Hodgson, Emma E; Koehn, Laura E; Oken, Kiva L; Siple, Margaret C; Stawitz, Christine C

    2015-05-26

    Forage fish support the largest fisheries in the world but also play key roles in marine food webs by transferring energy from plankton to upper trophic-level predators, such as large fish, seabirds, and marine mammals. Fishing can, thereby, have far reaching consequences on marine food webs unless safeguards are in place to avoid depleting forage fish to dangerously low levels, where dependent predators are most vulnerable. However, disentangling the contributions of fishing vs. natural processes on population dynamics has been difficult because of the sensitivity of these stocks to environmental conditions. Here, we overcome this difficulty by collating population time series for forage fish populations that account for nearly two-thirds of global catch of forage fish to identify the fingerprint of fisheries on their population dynamics. Forage fish population collapses shared a set of common and unique characteristics: high fishing pressure for several years before collapse, a sharp drop in natural population productivity, and a lagged response to reduce fishing pressure. Lagged response to natural productivity declines can sharply amplify the magnitude of naturally occurring population fluctuations. Finally, we show that the magnitude and frequency of collapses are greater than expected from natural productivity characteristics and therefore, likely attributed to fishing. The durations of collapses, however, were not different from those expected based on natural productivity shifts. A risk-based management scheme that reduces fishing when populations become scarce would protect forage fish and their predators from collapse with little effect on long-term average catches.

  8. Fatty acid profile of meat, diurnal changes in volatile fatty acids, rumen fluid parameters, and growth performance in Korean native (Hanwoo steers fed high- and low-forage diets supplemented with chromium-methionine

    Directory of Open Access Journals (Sweden)

    Bae-Hun Lee

    Full Text Available ABSTRACT The objective of this study was to determine the effects of forage level in diets supplemented with chromium-methionine (Cr-Met on rumen fluid parameters, meat fatty acid composition, and performance of Korean beef (Hanwoo steers. Twenty-three Hanwoo steers were used in this experiment. A completely randomized design and repeated measurements were used to analyze the data set. Beef steers were fed diets containing high (10 head; average body weight (BW = 525.1±27.5; forage:concentrate (F:C = 60:40 (60F and low (13 head; average BW = 531.8±32.4; F:C = 40:60 ratio (40F forage diets supplemented with Cr-Met for 60 d. Dry matter intake, BW, and feed efficiency were not different between the two treatment groups. Fatty acid composition of meat including myristate, stearate, and gamma linoleate was not different between the two groups; however, palmitate, palimtoleate, and linoleate were higher in 60F group than 40F group. Ammonia-N showed a higher trend in 40F group, whereas pH demonstrated higher values in 60F group. Ruminal acetate was higher in 60F group than 40F group and maintained a high trend throughout the sampling time, whereas no differences were found in ruminal propionate, butyrate, and valerate between two groups. A high-forage diet (60% improves meat quality and has no adverse effects on performance of Hanwoo steers.

  9. An Analysis of Java Programming Behaviors, Affect, Perceptions, and Syntax Errors among Low-Achieving, Average, and High-Achieving Novice Programmers

    Science.gov (United States)

    Rodrigo, Ma. Mercedes T.; Andallaza, Thor Collin S.; Castro, Francisco Enrique Vicente G.; Armenta, Marc Lester V.; Dy, Thomas T.; Jadud, Matthew C.

    2013-01-01

    In this article we quantitatively and qualitatively analyze a sample of novice programmer compilation log data, exploring whether (or how) low-achieving, average, and high-achieving students vary in their grasp of these introductory concepts. High-achieving students self-reported having the easiest time learning the introductory programming…

  10. An Analysis of Java Programming Behaviors, Affect, Perceptions, and Syntax Errors among Low-Achieving, Average, and High-Achieving Novice Programmers

    Science.gov (United States)

    Rodrigo, Ma. Mercedes T.; Andallaza, Thor Collin S.; Castro, Francisco Enrique Vicente G.; Armenta, Marc Lester V.; Dy, Thomas T.; Jadud, Matthew C.

    2013-01-01

    In this article we quantitatively and qualitatively analyze a sample of novice programmer compilation log data, exploring whether (or how) low-achieving, average, and high-achieving students vary in their grasp of these introductory concepts. High-achieving students self-reported having the easiest time learning the introductory programming…

  11. Seasonal Changes in Forage Nutrients and Mineral Contents in Water Resources,Forage and Yak Blood

    Institute of Scientific and Technical Information of China (English)

    阎萍

    2005-01-01

    This paper reports results of a study conducted to investigate the concentrations of seven mineral elements in yak blood, forage and water resources around the Qinghai Lake in Qinghai Province in different seasons. Meanwhile, the nutritional compositions of the forage were also surveyed. The results suggest that the mineral elements and the forage nutrients change in a seasonal pattern. In yak blood,the sodium(Na)concentration varies from 0.291 to 0.034 mg/mL,and this is lower than the normal value. In the forage,the ratio calcium(Ca)to phosphorus(P)is 4.06~7.47:1 and potassium(K)to Na 30~27:1. These results indicate that the nutrition of the yak in the area is deficient in Na but high in K. For the withered forage sampled in February,the protein content is only 31.14% of the total protein in the forage growing at puerile stage in June. The severe loss of protein by 68. 9% and decrease of effective nutrients in the wintered forage are considered to be the reasons resulting in the poor condition of yak in winter and spring seasons.

  12. The Effect of the Time Management Art on Academic Achievement among High School Students in Jordan

    Science.gov (United States)

    Al-Zoubi, Maysoon

    2016-01-01

    This study aimed at recognizing the effect of the Time Management Art on academic achievement among high school students in the Hashemite Kingdom of Jordan. The researcher employed the descriptive-analytic research to achieve the purpose of the study where he chose a sample of (2000) high school female and male students as respondents to the…

  13. A Longitudinal Investigation of Project-Based Instruction and Student Achievement in High School Social Studies

    Science.gov (United States)

    Summers, Emily J.; Dickinson, Gail

    2012-01-01

    This longitudinal study focused on how project-based instruction (PBI) influenced secondary social studies students' academic achievement and promoted College and Career Readiness (CCR). We explored and compared student achievement in a PBI high school versus a traditional instruction high school within the same rural school district. While…

  14. A Longitudinal Investigation of Project-Based Instruction and Student Achievement in High School Social Studies

    Science.gov (United States)

    Summers, Emily J.; Dickinson, Gail

    2012-01-01

    This longitudinal study focused on how project-based instruction (PBI) influenced secondary social studies students' academic achievement and promoted College and Career Readiness (CCR). We explored and compared student achievement in a PBI high school versus a traditional instruction high school within the same rural school district. While…

  15. Effects of a Collaborative Science Intervention on High Achieving Students' Learning Anxiety and Attitudes toward Science

    Science.gov (United States)

    Hong, Zuway-R.

    2010-01-01

    This study investigated the effects of a collaborative science intervention on high achieving students' learning anxiety and attitudes toward science. Thirty-seven eighth-grade high achieving students (16 boys and 21 girls) were selected as an experimental group who joined a 20-week collaborative science intervention, which integrated and utilized…

  16. Approaches to achieve high grain yield and high resource use efficiency in rice

    Directory of Open Access Journals (Sweden)

    Jianchang YANG

    2015-06-01

    Full Text Available This article discusses approaches to simultaneously increase grain yield and resource use efficiency in rice. Breeding nitrogen efficient cultivars without sacrificing rice yield potential, improving grain fill in later-flowering inferior spikelets and enhancing harvest index are three important approaches to achieving the dual goal of high grain yield and high resource use efficiency. Deeper root distribution and higher leaf photosynthetic N use efficiency at lower N rates could be used as selection criteria to develop N-efficient cultivars. Enhancing sink activity through increasing sugar-spikelet ratio at the heading time and enhancing the conversion efficiency from sucrose to starch though increasing the ratio of abscisic acid to ethylene in grains during grain fill could effectively improve grain fill in inferior spikelets. Several practices, such as post-anthesis controlled soil drying, an alternate wetting and moderate soil drying regime during the whole growing season, and non-flooded straw mulching cultivation, could substantially increase grain yield and water use efficiency, mainly via enhanced remobilization of stored carbon from vegetative tissues to grains and improved harvest index. Further research is needed to understand synergistic interaction between water and N on crop and soil and the mechanism underlying high resource use efficiency in high-yielding rice.

  17. Adaptive collective foraging in groups with conflicting nutritional needs

    Science.gov (United States)

    Senior, Alistair M.; Lihoreau, Mathieu; Charleston, Michael A.; Buhl, Jerome; Raubenheimer, David; Simpson, Stephen J.

    2016-01-01

    Collective foraging, based on positive feedback and quorum responses, is believed to improve the foraging efficiency of animals. Nutritional models suggest that social information transfer increases the ability of foragers with closely aligned nutritional needs to find nutrients and maintain a balanced diet. However, whether or not collective foraging is adaptive in a heterogeneous group composed of individuals with differing nutritional needs is virtually unexplored. Here we develop an evolutionary agent-based model using concepts of nutritional ecology to address this knowledge gap. Our aim was to evaluate how collective foraging, mediated by social retention on foods, can improve nutrient balancing in individuals with different requirements. The model suggests that in groups where inter-individual nutritional needs are unimodally distributed, high levels of collective foraging yield optimal individual fitness by reducing search times that result from moving between nutritionally imbalanced foods. However, where nutritional needs are highly bimodal (e.g. where the requirements of males and females differ) collective foraging is selected against, leading to group fission. In this case, additional mechanisms such as assortative interactions can coevolve to allow collective foraging by subgroups of individuals with aligned requirements. Our findings indicate that collective foraging is an efficient strategy for nutrient regulation in animals inhabiting complex nutritional environments and exhibiting a range of social forms. PMID:27152206

  18. Adaptive collective foraging in groups with conflicting nutritional needs.

    Science.gov (United States)

    Senior, Alistair M; Lihoreau, Mathieu; Charleston, Michael A; Buhl, Jerome; Raubenheimer, David; Simpson, Stephen J

    2016-04-01

    Collective foraging, based on positive feedback and quorum responses, is believed to improve the foraging efficiency of animals. Nutritional models suggest that social information transfer increases the ability of foragers with closely aligned nutritional needs to find nutrients and maintain a balanced diet. However, whether or not collective foraging is adaptive in a heterogeneous group composed of individuals with differing nutritional needs is virtually unexplored. Here we develop an evolutionary agent-based model using concepts of nutritional ecology to address this knowledge gap. Our aim was to evaluate how collective foraging, mediated by social retention on foods, can improve nutrient balancing in individuals with different requirements. The model suggests that in groups where inter-individual nutritional needs are unimodally distributed, high levels of collective foraging yield optimal individual fitness by reducing search times that result from moving between nutritionally imbalanced foods. However, where nutritional needs are highly bimodal (e.g. where the requirements of males and females differ) collective foraging is selected against, leading to group fission. In this case, additional mechanisms such as assortative interactions can coevolve to allow collective foraging by subgroups of individuals with aligned requirements. Our findings indicate that collective foraging is an efficient strategy for nutrient regulation in animals inhabiting complex nutritional environments and exhibiting a range of social forms.

  19. Redesigning forages with condensed tannins

    Science.gov (United States)

    Maximizing protein content in forages and minimizing protein loss during silage fermentation and rumen digestion are concerns for livestock and dairy producers. Substantial amounts of forage protein undergo proteolysis (breakdown) during the ensiling process and during rumen fermentation, transforme...

  20. Forage fiber effects on particle size reduction, ruminal stratification, and selective retention in heifers fed highly digestible grass/clover silages.

    Science.gov (United States)

    Schulze, A K S; Weisbjerg, M R; Storm, A C; Nørgaard, P

    2014-06-01

    The objective of this study was to investigate the effect of NDF content in highly digestible grass/clover silage on particle size reduction, ruminal stratification, and selective retention in dairy heifers. The reduction in particle size from feed to feces was evaluated and related to feed intake, chewing activity, and apparent digestibility. Four grass/clover harvests (Mixtures of Lolium perenne, Trifolium pratense, and Trifolium repens) were performed from early May to late August at different maturities, at different regrowth stages, and with different clover proportions, resulting in silages with NDF contents of 312, 360, 371, and 446 g/kg DM, respectively, and decreasing NDF digestibility with greater NDF content. Four rumen-fistulated dairy heifers were fed silage at 90% of ad libitum level as the only feed source in a 4 × 4 Latin square design. Silage, ingested feed boluses, medial and ventral ruminal digesta, and feces samples were washed with neutral detergent in nylon bags of 10-μm pore size, freeze dried, and divided into small (1 mm) particles by dry-sieving. Chewing activity, rumen pool size, and apparent digestibility were measured. Intake of NDF increased linearly from 2.3 to 2.8 kg/d with greater NDF content of forages (P = 0.01), but silages were exposed to similar eating time (P = 0.55) and rumination time per kg NDF (P = 0.35). No linear effect of NDF content was found on proportion of LP in ingested feed boluses (P = 0.31), medial rumen digesta (P = 0.95), ventral rumen digesta (P = 0.84), and feces (P = 0.09). Greater proportions of DM (P silages (P > 0.13). The LP proportion was >30% of particles in the ventral and medial rumen, whereas in the feces, the LP proportion was silages, stressing that the retention mechanism of large undigested particles lies elsewhere than with particle entrapment in the rumen mat. In this study, forage particle breakdown, ruminal stratification, and retention of particles in the rumen were not affected by NDF

  1. Achieving high strength and high ductility in magnesium alloy using hard-plate rolling (HPR) process.

    Science.gov (United States)

    Wang, Hui-Yuan; Yu, Zhao-Peng; Zhang, Lei; Liu, Chun-Guo; Zha, Min; Wang, Cheng; Jiang, Qi-Chuan

    2015-11-25

    Magnesium alloys are highly desirable for a wide range of lightweight structural components. However, rolling Mg alloys can be difficult due to their poor plasticity, and the strong texture yielded from rolling often results in poor plate forming ability, which limits their further engineering applications. Here we report a new hard-plate rolling (HPR) route which achieves a large reduction during a single rolling pass. The Mg-9Al-1Zn (AZ91) plates processed by HPR consist of coarse grains of 30-60 μm, exhibiting a typical basal texture, fine grains of 1-5 μm and ultrafine (sub) grains of 200-500 nm, both of the latter two having a weakened texture. More importantly, the HPR was efficient in gaining a simultaneous high strength and uniform ductility, i.e., ~371 MPa and ~23%, respectively. The superior properties should be mainly attributed to the cooperation effect of the multimodal grain structure and weakened texture, where the former facilitates a strong work hardening while the latter promotes the basal slip. The HPR methodology is facile and effective, and can avoid plate cracking that is prone to occur during conventional rolling processes. This strategy is applicable to hard-to-deform materials like Mg alloys, and thus has a promising prospect for industrial application.

  2. Optimal Foraging in Semantic Memory

    Science.gov (United States)

    Hills, Thomas T.; Jones, Michael N.; Todd, Peter M.

    2012-01-01

    Do humans search in memory using dynamic local-to-global search strategies similar to those that animals use to forage between patches in space? If so, do their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging? Results from a number of fields suggest these possibilities, including the shared…

  3. The impact of collective teacher efficacy on student achievement in high school science

    Science.gov (United States)

    Burcham, Mark W.

    This dissertation was designed to examine the impact of collective teacher efficacy on high school science achievement by looking at relationships among collective teacher efficacy, its two constructs, group competence and group task analysis, and high school science achievement scores at four rural high schools in Northwestern North Carolina. The researcher gathered historical test data from the testing coordinator from the school system and then administered the Collective Teacher Efficacy Instrument, developed by Goddard, Hoy, and Woolfolk Hoy (2000), to 24 science teachers from the four high schools. Using this information, the researcher conducted statistical analyses to determine the relationships among collective teacher efficacy, group competence, and group task analysis as compared with the tested science curriculum (physical science, biology, chemistry, and physics). The researcher also examined which construct was the most contributing factor and examined differences in efficacy levels and student achievement levels at each high school. Analysis of the data from this study indicated collective teacher efficacy, as well as its two constructs, group competence and group task analysis, does have a positive impact on student achievement in high school science. Analysis of the data revealed group competence is the major contributing factor for student achievement in biology and group task analysis is the major contributing factor for student achievement in physical science, chemistry, and physics. Further analysis of the data in this study, also revealed that the two high schools with the highest levels of collective teacher efficacy had the highest levels of student achievement.

  4. Habitat-specific foraging strategies in Australasian gannets

    Directory of Open Access Journals (Sweden)

    Melanie R. Wells

    2016-07-01

    Full Text Available Knowledge of top predator foraging adaptability is imperative for predicting their biological response to environmental variability. While seabirds have developed highly specialised techniques to locate prey, little is known about intraspecific variation in foraging strategies with many studies deriving information from uniform oceanic environments. Australasian gannets (Morus serrator typically forage in continental shelf regions on small schooling prey. The present study used GPS and video data loggers to compare habitat-specific foraging strategies at two sites of contrasting oceanographic regimes (deep water near the continental shelf edge, n=23; shallow inshore embayment, n=26, in south-eastern Australia. Individuals from the continental shelf site exhibited pelagic foraging behaviours typical of gannet species, using local enhancement to locate and feed on small schooling fish; in contrast only 50% of the individuals from the inshore site foraged offshore, displaying the typical pelagic foraging strategy. The remainder adopted a strategy of searching sand banks in shallow inshore waters in the absence of conspecifics and other predators for large, single prey items. Furthermore, of the individuals foraging inshore, 93% were male, indicating that the inshore strategy may be sex-specific. Large inter-colony differences in Australasian gannets suggest strong plasticity in foraging behaviours, essential for adapting to environmental change.

  5. Habitat-specific foraging strategies in Australasian gannets.

    Science.gov (United States)

    Wells, Melanie R; Angel, Lauren P; Arnould, John P Y

    2016-07-15

    Knowledge of top predator foraging adaptability is imperative for predicting their biological response to environmental variability. While seabirds have developed highly specialised techniques to locate prey, little is known about intraspecific variation in foraging strategies with many studies deriving information from uniform oceanic environments. Australasian gannets (Morus serrator) typically forage in continental shelf regions on small schooling prey. The present study used GPS and video data loggers to compare habitat-specific foraging strategies at two sites of contrasting oceanographic regimes (deep water near the continental shelf edge, n=23; shallow inshore embayment, n=26), in south-eastern Australia. Individuals from the continental shelf site exhibited pelagic foraging behaviours typical of gannet species, using local enhancement to locate and feed on small schooling fish; in contrast only 50% of the individuals from the inshore site foraged offshore, displaying the typical pelagic foraging strategy. The remainder adopted a strategy of searching sand banks in shallow inshore waters in the absence of conspecifics and other predators for large, single prey items. Furthermore, of the individuals foraging inshore, 93% were male, indicating that the inshore strategy may be sex-specific. Large inter-colony differences in Australasian gannets suggest strong plasticity in foraging behaviours, essential for adapting to environmental change.

  6. Decreased latent inhibition is associated with increased creative achievement in high-functioning individuals.

    Science.gov (United States)

    Carson, Shelley H; Peterson, Jordan B; Higgins, Daniel M

    2003-09-01

    Reductions in latent inhibition (LI), the capacity to screen from conscious awareness stimuli previously experienced as irrelevant, have been generally associated with the tendency towards psychosis. However, "failure" to screen out previously irrelevant stimuli might also hypothetically contribute to original thinking, particularly in combination with high IQ. Meta-analysis of two studies, conducted on youthful high-IQ samples. demonstrated that high lifetime creative achievers had significantly lower LI scores than low creative achievers (r(effect size) = .31, p = .0003, one-tailed). Eminent creative achievers (participants under 21 years who reported unusually high scores in a single domain of creative achievement) were 7 times more likely to have low rather than high LI scores, chi2 (1, N = 25) = 10.69, phi = .47. p = .003.

  7. Instructional, Transformational, and Managerial Leadership and Student Achievement: High School Principals Make a Difference

    Science.gov (United States)

    Valentine, Jerry W.; Prater, Mike

    2011-01-01

    This statewide study examined the relationships between principal managerial, instructional, and transformational leadership and student achievement in public high schools. Differences in student achievement were found when schools were grouped according to principal leadership factors. Principal leadership behaviors promoting instructional and…

  8. Early Reading Skills and Academic Achievement Trajectories of Students Facing Poverty, Homelessness, and High Residential Mobility

    Science.gov (United States)

    Herbers, Janette E.; Cutuli, J. J.; Supkoff, Laura M.; Heistad, David; Chan, Chi-Keung; Hinz, Elizabeth; Masten, Ann S.

    2012-01-01

    This investigation tested the importance of early academic achievement for later achievement trajectories among 18,011 students grouped by level of socioeconomic risk. Students considered to be at highest risk were those who experienced homelessness or high residential mobility (HHM). HHM students were compared with students eligible for free…

  9. Instructional, Transformational, and Managerial Leadership and Student Achievement: High School Principals Make a Difference

    Science.gov (United States)

    Valentine, Jerry W.; Prater, Mike

    2011-01-01

    This statewide study examined the relationships between principal managerial, instructional, and transformational leadership and student achievement in public high schools. Differences in student achievement were found when schools were grouped according to principal leadership factors. Principal leadership behaviors promoting instructional and…

  10. Intergenerational Closure and Academic Achievement in High School: A New Evaluation of Coleman's Conjecture

    Science.gov (United States)

    Morgan, Stephen L.; Todd, Jennifer J.

    2009-01-01

    This article reexamines the conjecture of James S. Coleman that intergenerational social closure promotes student achievement in high schools, analyzing the best national data on academic achievement and social networks: the 2002 and 2004 waves of the Education Longitudinal Study. The results show that within the Catholic school sector, schools…

  11. Achievement Motivation in High School: Contrasting Theoretical Models in the Classroom.

    Science.gov (United States)

    Garcia-Celay, I. Montero; Tapia, J. Alonso

    1992-01-01

    Three models of achievement motivation in the classroom are contrasted. Results with 155 high school students suggest that the model of C. S. Dweck and E. S. Elliott offers a better explanation of the relationships among achievement motivation, attributions, emotional reactions, expectancies, and performance than do the other models. (SLD)

  12. The Effects of Explicit Teaching of Metastrategic Knowledge on Low- And High-Achieving Students

    Science.gov (United States)

    Zohar, Anat; Peled, Bracha

    2008-01-01

    This study assessed the effects of explicit teaching of metastrategic knowledge (MSK) on gains of low-achieving (LA) and high-achieving (HA) 5th grade students (N=41). Gains in reasoning scores of students from the Experimental group (compared to students from the control group) were obtained on the strategic and on the metastrategic level. Gains…

  13. Unforgiving Confucian Culture: A Breeding Ground for High Academic Achievement, Test Anxiety and Self-Doubt?

    Science.gov (United States)

    Stankov, Lazar

    2010-01-01

    This paper reviews findings from several studies that contribute to our understanding of cross-cultural differences in academic achievement, anxiety and self-doubt. The focus is on comparisons between Confucian Asian and European regions. Recent studies indicate that high academic achievement of students from Confucian Asian countries is…

  14. Accelerated Mathematics and High-Ability Students' Math Achievement in Grades Three and Four

    Science.gov (United States)

    Stanley, Ashley M.

    2011-01-01

    The purpose of this study was to explore the relationship between the use of a computer-managed integrated learning system entitled Accelerated Math (AM) as a supplement to traditional mathematics instruction on achievement as measured by TerraNova achievement tests of third and fourth grade high-ability students. Gender, socioeconomic status, and…

  15. Understanding and Reversing Underachievement, Low Achievement, and Achievement Gaps among High-Ability African American Males in Urban School Contexts

    Science.gov (United States)

    Ford, Donna Y.; Moore, James L., III

    2013-01-01

    This article focuses on the achievement gap, with attention devoted to underachievement and low achievement among African American males in urban school contexts. More specifically, the article explains problems and issues facing or confronting these Black male students in urban education settings. A central part of this discussion is grounded in…

  16. Field application of mycorrhizal bio-inoculants affects the mineral uptake of a forage legume (Hedysarum coronarium L.) on a highly calcareous soil.

    Science.gov (United States)

    Labidi, S; Jeddi, F Ben; Tisserant, B; Yousfi, M; Sanaa, M; Dalpé, Y; Sahraoui, A Lounès-Hadj

    2015-05-01

    The efficiency of two mycorrhizal bio-inoculants on the mineral uptake during the growth stages of a Mediterranean forage legume sulla (Hedysarum coronarium L.) was studied in the field on a highly calcareous soil. The first inoculum (Mm) was made up of a mixture of native arbuscular mycorrhizal fungi (AMF) isolated from calcareous soils: Septoglomus constrictum, Funneliformis geosporum, Glomus fuegianum, Rhizophagus irregularis and Glomus sp. The second was a commercial inoculum (Mi) containing one AMF species: R. irregularis. Both mycorrhizal inoculants increased total and arbuscular colonization of sulla roots. Inoculation with Mm showed a positive effect on sulla shoot dry weight (SDW) when compared to Mi and non-inoculated plants (control). Mineral contents (P, Mg, Mn, Fe) were higher in the shoots of sulla plants cultivated on mycorrhiza-inoculated plots compared to non-inoculated ones. This enhancement was observed during the flowering stage for P, Mg and Mn and during the rosette stage for Fe. An increase in P content of 50 % in plants inoculated with Mm compared to non-inoculated ones may be explained by the induction of root alkaline and acid phosphatase activities. Higher efficiency of native AMF species adapted to calcareous soils opens the way towards the development of mycorrhiza bio-fertilizers targeted to improve sustainable fertilization management in such soils.

  17. Impacts of comprehensive reading instruction on diverse outcomes of low- and high-achieving readers.

    Science.gov (United States)

    Guthrie, John T; McRae, Angela; Coddington, Cassandra S; Lutz Klauda, Susan; Wigfield, Allan; Barbosa, Pedro

    2009-01-01

    Low-achieving readers in Grade 5 often lack comprehension strategies, domain knowledge, word recognition skills, fluency, and motivation to read. Students with such multiple reading needs seem likely to benefit from instruction that supports each of these reading processes. The authors tested this expectation experimentally by comparing the effects of Concept-Oriented Reading Instruction (CORI) with traditional instruction (TI) on several outcomes in a 12-week intervention for low achievers and high achievers. Low achievers in the CORI group were afforded explicit instruction, leveled texts, and motivation support. Compared with TI students, CORI students scored higher on posttest measures of word recognition speed, reading comprehension on the Gates-MacGinitie Reading Test, and ecological knowledge. CORI was equally effective for lower achievers and higher achievers. Explicitly supporting multiple aspects of reading simultaneously appeared to benefit diverse learners on a range of reading outcomes.

  18. The essence of reliability estimation during operational life for achieving high system dependability

    NARCIS (Netherlands)

    Khan, M.A.; Kerkhoff, Hans G.

    2013-01-01

    System dependability has become important for critical applications in recent years as technology is moving towards smaller dimensions. Achieving high dependability can be supported by reliability estimations during the operational life. In addition this requires a workflow for regularly monitoring

  19. The essence of reliability estimation during operational life for achieving high system dependability

    NARCIS (Netherlands)

    Khan, Muhammad Aamir; Kerkhoff, Hans G.

    2013-01-01

    System dependability has become important for critical applications in recent years as technology is moving towards smaller dimensions. Achieving high dependability can be supported by reliability estimations during the operational life. In addition this requires a workflow for regularly monitoring

  20. Pronounced Seasonal Changes in the Movement Ecology of a Highly Gregarious Central-Place Forager, the African Straw-Coloured Fruit Bat (Eidolon helvum.

    Directory of Open Access Journals (Sweden)

    Jakob Fahr

    Full Text Available Straw-coloured fruit bats (Eidolon helvum migrate over vast distances across the African continent, probably following seasonal bursts of resource availability. This causes enormous fluctuations in population size, which in turn may influence the bats' impact on local ecosystems. We studied the movement ecology of this central-place forager with state-of-the-art GPS/acceleration loggers and concurrently monitored the seasonal fluctuation of the colony in Accra, Ghana. Habitat use on the landscape scale was assessed with remote sensing data as well as ground-truthing of foraging areas.During the wet season population low (~ 4000 individuals, bats foraged locally (3.5-36.7 km in urban areas with low tree cover. Major food sources during this period were fruits of introduced trees. Foraging distances almost tripled (24.1-87.9 km during the dry season population peak (~ 150,000 individuals, but this was not compensated for by reduced resting periods. Dry season foraging areas were random with regard to urban footprint and tree cover, and food consisted almost exclusively of nectar and pollen of native trees.Our study suggests that straw-coloured fruit bats disperse seeds in the range of hundreds of meters up to dozens of kilometres, and pollinate trees for up to 88 km. Straw-coloured fruit bats forage over much larger distances compared to most other Old World fruit bats, thus providing vital ecosystem services across extensive landscapes. We recommend increased efforts aimed at maintaining E. helvum populations throughout Africa since their keystone role in various ecosystems is likely to increase due to the escalating loss of other seed dispersers as well as continued urbanization and habitat fragmentation.

  1. Breeding Better Forages to Help Feed Man and Preserve and Enhance the Environment

    Science.gov (United States)

    Burton, Glenn W.

    1973-01-01

    Discusses the importance of forages in agriculture, and expresses the need for the same high level of technology that is used in the production of corn, wheat, and rice to be applied to forage production. Describes promising forage species, breeding objectives, and breeding procedures used in research. (JR)

  2. Ant Foraging As an Indicator of Tropical Dry Forest Restoration.

    Science.gov (United States)

    Hernández-Flores, J; Osorio-Beristain, M; Martínez-Garza, C

    2016-08-01

    Variation in foraging behavior may indicate differences in food availability and allow assessment of restoration actions. Ants are prominent bioindicators used in assessing ecological responses to disturbance. However, behavioral data have been poorly incorporated as an index. The foraging performance of red harvester ants was quantified in order to evaluate the success of a restoration ecology experiment in the tropical dry forest of Sierra de Huautla, Morelos, in central Mexico. Foraging performance by granivorous, Pogonomyrmex barbatus, ants was diminished after 6 and 8 years of cattle grazing and wood harvest were excluded as part of a restoration experiment in a highly degraded biome. Despite investing more time in foraging, ant colonies in exclusion plots showed lower foraging success and acquired less seed biomass than colonies in control plots. In line with the predictions of optimal foraging theory, in restored plots where ant foraging performance was poor, ants harvested a higher diversity of seeds. Reduced foraging success and increased harvest of non-preferred foods in exclusion plots were likely due to the growth of herbaceous vegetation, which impedes travel by foragers. Moreover, by 8 years of exclusion, 37% of nests in exclusion plots had disappeared compared to 0% of nests in control plots. Ants' foraging success and behavior were sensitive to changes in habitat quality due to the plant successional process triggered by a restoration intervention. This study spotlights on the utility of animal foraging behavior in the evaluation of habitat restoration programs. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  3. Elevation and forest clearing effects on foraging differ between surface--and subterranean--foraging army ants (Formicidae: Ecitoninae).

    Science.gov (United States)

    Kumar, Anjali; O'Donnell, Sean

    2009-01-01

    1. Forest fragmentation often results in a matrix of open areas mixed with patches of forest. Both biotic and abiotic factors can affect consumer species' ability to utilize the altered habitat, especially for species that range over large areas searching for prey. 2. Army ants (Formicidae: Ecitoninae) are highly mobile top predators in terrestrial Neotropical ecosystems. Army ant foraging behaviour is influenced by forest clearing at lowland sites, and clearing can reduce army ant population persistence. 3. Because high temperatures are implicated in hindering above-ground army ant foraging, we predicted that forest clearing effects on army ant foraging would be reduced at higher (cooler) elevations in montane forest. We also predicted that subterranean foraging, employed by some army ant species, would buffer them from the negative effects of forest clearing. 4. We quantified the foraging rates of above-ground and underground foraging army ants at eight sites along an elevational gradient from 1090 to 1540 m a.s.l. We asked whether these two foraging strategies cause a difference in the ability of army ants to forage in open matrix areas relative to elevationally matched forested habitats, and whether elevation predicts open area vs. forest foraging rate differences. 5. As predicted, army ants that forage above-ground had lower foraging rates in open areas, but the open area vs. forest difference declined with elevation. In contrast, underground foragers were not affected by habitat type, and underground foraging rates increased with elevation. Ground surface temperatures were higher in open areas than forested areas. Temperatures declined with elevation, and temperature differences between open and forested areas decreased with elevation. 6. We conclude that army ants that forage above-ground may be restricted to forested areas due to a thermal tolerance threshold, but that they are released from this limitation at higher elevations. We further suggest that

  4. Energetic optimisation of foraging honeybees: flexible change of strategies in response to environmental challenges.

    Science.gov (United States)

    Stabentheiner, Anton; Kovac, Helmut

    2014-01-01

    Heterothermic insects like honeybees, foraging in a variable environment, face the challenge of keeping their body temperature high to enable immediate flight and to promote fast exploitation of resources. Because of their small size they have to cope with an enormous heat loss and, therefore, high costs of thermoregulation. This calls for energetic optimisation which may be achieved by different strategies. An 'economizing' strategy would be to reduce energetic investment whenever possible, for example by using external heat from the sun for thermoregulation. An 'investment-guided' strategy, by contrast, would be to invest additional heat production or external heat gain to optimize physiological parameters like body temperature which promise increased energetic returns. Here we show how honeybees balance these strategies in response to changes of their local microclimate. In a novel approach of simultaneous measurement of respiration and body temperature foragers displayed a flexible strategy of thermoregulatory and energetic management. While foraging in shade on an artificial flower they did not save energy with increasing ambient temperature as expected but acted according to an 'investment-guided' strategy, keeping the energy turnover at a high level (∼56-69 mW). This increased thorax temperature and speeded up foraging as ambient temperature increased. Solar heat was invested to increase thorax temperature at low ambient temperature ('investment-guided' strategy) but to save energy at high temperature ('economizing' strategy), leading to energy savings per stay of ∼18-76% in sunshine. This flexible economic strategy minimized costs of foraging, and optimized energetic efficiency in response to broad variation of environmental conditions.

  5. Identifying robustness in the regulation of collective foraging of ant colonies using an interaction-based model with backward bifurcation.

    Science.gov (United States)

    Udiani, Oyita; Pinter-Wollman, Noa; Kang, Yun

    2015-02-21

    Collective behaviors in social insect societies often emerge from simple local rules. However, little is known about how these behaviors are dynamically regulated in response to environmental changes. Here, we use a compartmental modeling approach to identify factors that allow harvester ant colonies to regulate collective foraging activity in response to their environment. We propose a set of differential equations describing the dynamics of: (1) available foragers inside the nest, (2) active foragers outside the nest, and (3) successful returning foragers, to understand how colony-specific parameters, such as baseline number of foragers, interactions among foragers, food discovery rates, successful forager return rates, and foraging duration might influence collective foraging dynamics, while maintaining functional robustness to perturbations. Our analysis indicates that the model can undergo a forward (transcritical) bifurcation or a backward bifurcation depending on colony-specific parameters. In the former case, foraging activity persists when the average number of recruits per successful returning forager is larger than one. In the latter case, the backward bifurcation creates a region of bistability in which the size and fate of foraging activity depends on the distribution of the foraging workforce among the model's compartments. We validate the model with experimental data from harvester ants (Pogonomyrmex barbatus) and perform sensitivity analysis. Our model provides insights on how simple, local interactions can achieve an emergent and robust regulatory system of collective foraging activity in ant colonies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. The Relationship between Cognitive and Emotional Intelligence and High School Academic Achievement.

    Science.gov (United States)

    Matešić, Krunoslav

    2015-06-01

    The study investigated the relationship between intelligence, emotional intelligence and academic achievement in high school. The study was conducted within the standardization of two instruments for Croatian samples. A total of 369 high school students from the Republic of Croatia participated in the study. They completed the Naglieri Nonverbal Ability Test (NNAT)--a test of cognitive intelligence and the BarOn Emotional Quotient Inventory: Youth Version (EQ-i:YV). Academic achievement criteria were general school achievement, Croatian language and mathematics. Several regression analyses were conducted on the results. The results show that cognitive intelligence and the adaptability scale to be consistent predictors of academic achievement. Emotional intelligence was not shown to be a significant predictor of school success.

  7. Investigating Optimal Foraging Theory in the Laboratory

    Science.gov (United States)

    Harden, Siegfried; Grilliot, Matthew E.

    2014-01-01

    Optimal foraging theory is a principle that is often presented in the community ecology section of biology textbooks, but also can be demonstrated in the laboratory. We introduce a lab activity that uses an interactive strategy to teach high school and/or college students about this ecological concept. The activity is ideal because it engages…

  8. An Evaluation of the English Achievement Test for Junior High School Graduation 2012

    Institute of Scientific and Technical Information of China (English)

    叶译

    2013-01-01

    This paper evaluates the Achievement Test for Junior High School Graduation in reliability, validity and practicality, which is aimed to help junior English teachers to understand how to identify a useful test and develop their test writing skills as well as improve their teaching. The result suggests that the Achievement Test is a reasonably reliable and valid test though some of the listening items need to be improved. It is the ideal frame of evaluating language learning through language testing.

  9. Social Goals, Social Status, and Problem Behavior among Low-Achieving and High-Achieving Adolescents from Rural Schools

    Science.gov (United States)

    Ludden, Alison Bryant

    2012-01-01

    The current research examines how social goals and perceptions of what is needed for social status at school relate to school misbehavior and substance use among rural adolescents (N = 683). Results indicate that social goals and perceptions of social status have differential links to problem behaviors depending upon adolescents' achievement.…

  10. Evaluation of English Achievement Test: A Comparison between High and Low Achievers amongst Selected Elementary School Students of Pakistan

    Science.gov (United States)

    Haider, Zubair; Latif, Farah; Akhtar, Samina; Mushtaq, Maria

    2012-01-01

    Validity, reliability and item analysis are critical to the process of evaluating the quality of an educational measurement. The present study evaluates the quality of an assessment constructed to measure elementary school student's achievement in English. In this study, the survey model of descriptive research was used as a research method.…

  11. Emotional Intelligence as a Predictor of Leadership of Kuwaiti High and Low Achieving 11th Graders

    Science.gov (United States)

    Alnabhan, Mousa

    2010-01-01

    The current study examined the association between emotional intelligence (EI) and the Leadership components (L) of high school students in the state of Kuwait. The possibility of predicting each leadership component via emotional intelligence components was investigated for high and low achievers. A sample of 11th grade students from Kuwaiti…

  12. The Role of Teachers at University: What Do High Achiever Students Look for?

    Science.gov (United States)

    Monteiro, Silvia; Almeida, Leandro S.; Vasconcelos, Rosa M.

    2012-01-01

    The perceptions of students about their teachers have interested the academic and scientific community, regarding the improvement of the quality of higher education. This paper presents data obtained from interviews conducted with ten high achiever engineering students and focuses on the characteristics of teachers that are highly valued by the…

  13. Study-Orientation of High and Low Academic Achievers at Secondary Level in Pakistan

    Science.gov (United States)

    Sarwar, Muhammad; Bashir, Muhammad; Khan, Muhammad Naemullah; Khan, Muhammad Saeed

    2009-01-01

    The study orientation of low and high academic achievers was compared, measured through a self-developed study orientation scale (SOS) primarily based on 47 items comparing study habits and attitude. Students' marks obtained in the 10th grade Examination determined the measure of academic performance. The analysis revealed that the high achievers…

  14. Mathematics Achievement with Digital Game-Based Learning in High School Algebra 1 Classes

    Science.gov (United States)

    Ferguson, Terri Lynn Kurley

    2014-01-01

    This study examined the impact of digital game-based learning (DGBL) on mathematics achievement in a rural high school setting in North Carolina. A causal comparative research design was used in this study to collect data to determine the effectiveness of DGBL in high school Algebra 1 classes. Data were collected from the North Carolina…

  15. The Effects of Modeling Instruction on High School Physics Academic Achievement

    Science.gov (United States)

    Wright, Tiffanie L.

    2012-01-01

    The purpose of this study was to explore whether Modeling Instruction, compared to traditional lecturing, is an effective instructional method to promote academic achievement in selected high school physics classes at a rural middle Tennessee high school. This study used an "ex post facto," quasi-experimental research methodology. The…

  16. Impact of Principal Leadership on Catholic High School Students' Academic Achievement in Edo State, Nigeria

    Science.gov (United States)

    Imhangbe, Osayamen Samson

    2012-01-01

    Over the years, students of Catholic High/Senior secondary schools in Edo state, Nigeria have maintained a significantly higher level of academic achievement than their counterparts in public schools in the state. This development has not only been a cause of serious concern for parents of students who attend public High/Senior secondary schools…

  17. Disruption of foraging by a dominant invasive species to decrease its competitive ability.

    Science.gov (United States)

    Westermann, Fabian Ludwig; Suckling, David Maxwell; Lester, Philip John

    2014-01-01

    Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z)-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants.

  18. Niche dynamics of shorebirds in Delaware Bay: Foraging behavior, habitat choice and migration timing

    Science.gov (United States)

    Novcic, Ivana

    2016-08-01

    Niche differentiation through resource partitioning is seen as one of the most important mechanisms of diversity maintenance contributing to stable coexistence of different species within communities. In this study, I examined whether four species of migrating shorebirds, dunlins (Calidris alpina), semipalmated sandpipers (Calidris pusilla), least sandpipers (Calidris minutilla) and short-billed dowitchers (Limnodromus griseus), segregate by time of passage, habitat use and foraging behavior at their major stopover in Delaware Bay during spring migration. I tested the prediction that most of the separation between morphologically similar species will be achieved by differential migration timing. Despite the high level of overlap along observed niche dimensions, this study demonstrates a certain level of ecological separation between migrating shorebirds. The results of analyses suggest that differential timing of spring migration might be the most important dimension along which shorebird species segregate while at stopover in Delaware Bay. Besides differences in time of passage, species exhibited differences in habitat use, particularly least sandpipers that foraged in vegetated areas of tidal marshes more frequently than other species, as well as short-billed dowitchers that foraged in deeper water more often than small sandpipers did. Partitioning along foraging techniques was less prominent than segregation along temporal or microhabitat dimensions. Such ranking of niche dimensions emphasizes significance of temporal segregation of migratory species - separation of species by time of passage may reduce the opportunity for interspecific aggressive encounters, which in turn can have positive effects on birds' time and energy budget during stopover period.

  19. Disruption of foraging by a dominant invasive species to decrease its competitive ability.

    Directory of Open Access Journals (Sweden)

    Fabian Ludwig Westermann

    Full Text Available Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants.

  20. Disruption of Foraging by a Dominant Invasive Species to Decrease Its Competitive Ability

    Science.gov (United States)

    Westermann, Fabian Ludwig; Suckling, David Maxwell; Lester, Philip John

    2014-01-01

    Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z)-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants. PMID:24594633

  1. Academic achievement and career choice in science: Perceptions of African American urban high school students

    Science.gov (United States)

    Jones, Sheila Kay

    2007-12-01

    Low test scores in science and fewer career choices in science among African American high school students than their White counterparts has resulted in lower interest during high school and an underrepresentation of African Americans in science and engineering fields. Reasons for this underachievement are not known. This qualitative study used a grounded theory methodology to examine what influence parental involvement, ethnic identity, and early mentoring had on the academic achievement in science and career choice in science of African American urban high school 10th grade students. Using semi-structured open-ended questions in individual interviews and focus groups, twenty participants responded to questions about African American urban high school student achievement in science and their career choice in science. The median age of participants was 15 years; 85% had passed either high school biology or physical science. The findings of the study revealed influences and interactions of selected factors on African American urban high school achievement in science. Sensing potential emerged as the overarching theme with six subthemes; A Taste of Knowledge, Sounds I Hear, Aromatic Barriers, What Others See, The Touch of Others, and The Sixth Sense. These themes correlate to the natural senses of the human body. A disconnect between what science is, their own individual learning and success, and what their participation in science could mean for them and the future of the larger society. Insight into appropriate intervention strategies to improve African American urban high school achievement in science was gained.

  2. High frequency wide-band transformer uses coax to achieve high turn ratio and flat response

    Science.gov (United States)

    De Parry, T.

    1966-01-01

    Center-tap push-pull transformer with toroidal core helically wound with a single coaxial cable creates a high frequency wideband transformer. This transformer has a high-turn ratio, a high coupling coefficient, and a flat broadband response.

  3. Using Large Data to Analyze the Effect of Learning Attitude for Cooperative Learning between the High Achievement Students and the Low Achievement Students

    Science.gov (United States)

    Chia-Ling, Hsu; Ya-Fung, Chang

    2017-01-01

    This study is to investigate the effect of the cooperation learning between the high achievement students and the low achievement students. Nowadays, the influences of the flipped classroom are all over the world in the secondary school education. Therefore, the cooperative learning becomes hot teaching strategies again. However, the learning…

  4. What leadership behaviors were demonstrated by the principal in a high poverty, high achieving elementary school?

    Directory of Open Access Journals (Sweden)

    E. Hayet J. Woods

    2016-12-01

    Full Text Available Examined through the lens of leadership, were the behaviors of a principal as perceived by stakeholders. The following themes emerged: (1 Educating the Whole Child, with the subthemes: (a providing basic needs; (b academic interventions based on achievement data; (c an emphasis on reading; (d extended academic time; and (e relationships; and (2 Synergy of Expectations, with the subthemes: (a consistent student expectations; (b increased staff accountability; and (c community involvement. The researchers found that the principal by demonstrating behaviors as a change agent, a creator of vision, and a provider of necessary support and strategies, rather than adopting numerous programs, the school personnel were able to increase and sustain academic achievement of the students of poverty as well as their peers. Implications for principal practices, along with leadership preparatory programs are significant.

  5. Collective foraging in heterogeneous landscapes

    CERN Document Server

    Bhattacharya, Kunal

    2013-01-01

    Animals foraging alone are hypothesized to optimize the encounter rates with resources through L\\'evy walks. However, the issue of how the interactions between multiple foragers influence their search efficiency is still not completely understood. To address this, we consider a model to study the optimal strategy for a group of foragers searching for targets distributed heterogeneously. In our model foragers move on a square lattice containing immobile but regenerative targets. At any instant a forager is able to detect only those targets that happen to be in the same site. However, we allow the foragers to have information about the state of other foragers. A forager who has not detected any target walks towards the nearest location, where another forager has detected a target, with probability $\\exp{\\left(-\\alpha d\\right)}$, where $d$ is the distance and $\\alpha$ is a parameter. The model reveals that neither overcrowding ($\\alpha\\to 0$) nor independent searching ($\\alpha\\to\\infty$) is beneficial for the gr...

  6. High-Stakes Testing and Student Achievement: Does Accountability Pressure Increase Student Learning?

    Directory of Open Access Journals (Sweden)

    Sharon L. Nichols

    2006-01-01

    Full Text Available This study examined the relationship between high-stakes testing pressure and student achievement across 25 states. Standardized portfolios were created for each study state. Each portfolio contained a range of documents that told the “story” of accountability implementation and impact in that state. Using the “law of comparative judgments,” over 300 graduate-level education students reviewed one pair of portfolios and made independent evaluations as to which of the two states’ portfolios reflected a greater degree of accountability pressure. Participants’ judgments yielded a matrix that was converted into a single rating system that arranged all 25 states on a continuum of accountability “pressure” from high to low. Using this accountability pressure rating we conducted a series of regression and correlation analyses. We found no relationship between earlier pressure and later cohort achievement for math at the fourth- and eighth-grade levels on the National Assessment of Educational Progress tests. Further, no relationship was found between testing pressure and reading achievement on the National Assessment of Education Progress tests at any grade level or for any ethnic student subgroup. Data do suggest, however, that a case could be made for a causal relationship between high-stakes testing pressure and subsequent achievement on the national assessment tests—but only for fourth grade, non-cohort achievement and for some ethnic subgroups. Implications and directions for future studies are discussed.

  7. 2×2 dominant achievement goal profiles in high-level swimmers.

    Science.gov (United States)

    Fernandez-Rio, Javier; Cecchini Estrada, Jose A; Mendez-Giménez, Antonio; Fernández-Garcia, Benjamín; Saavedra, Pablo

    2014-01-01

    The goal of this study was to assess achievement goal dominance, self-determined situational motivation and competence in high-level swimmers before and after three training sessions set at different working intensities (medium, sub-maximal and maximal). Nineteen athletes (males, n=9, 18.00±2.32 years; females, n=10, 16.30±2.01 years, range = 14-18) agreed to participate. They completed a questionnaire that included the Dominant Achievement Goal assessment instrument, the 2×2 Achievement Goals Questionnaire for Sport (AGQ-S), The Situational Motivation Scale (SIMS) and the Competence subscale of the Basic Psychological Needs in Exercise questionnaire (BPNES). Results indicated that participants overwhelmingly showed mastery-approach achievement goal dominance, and it remained stable at the conclusion of the different training sessions under all intensity levels. This profile was positively correlated to self-determined situational motivation and competence. However, swimmers' feelings of competence increased only after the medium intensity level training session. After the completion of the maximal intensity training session, swimmers' self-determined motivation was significantly lower compared to the other two training sessions, which could be caused by a temporary period of burnout. Results indicated that high-level swimmers had a distinct mastery-approach dominant achievement goal profile that was not affected by the workload of the different training sessions. They also showed high levels of self-determined situational motivation and competence. However, heavy workloads should be controlled because they can cause transitory burnout.

  8. The Exploration of the Associations between Locus of Control & High School Students’ Language Achievement

    Directory of Open Access Journals (Sweden)

    Abbas Eslami-Rasekh

    2012-07-01

    Full Text Available The purpose of the study is to determine the relationships between locus of control (LOC orientation and high school students’ language achievement. The popular categorization of internals and externals was taken into account. The participants of this study were 121 high school students in the second, third and pre-university grades in two public high schools of Isfahan, Iran. One of the instruments used in the study was an adopted version of Julian Rotters’ locus of control (1966 which identified internal and external orientations. The participants’ English scores were regarded as the measure of their achievement. Besides, a questionnaire consisting of 29 items was administered to all 121 students. Responses were put into one way and two-way ANOVA, the regression analysis, the independent t-test, chi-square and linear regression analysis to compare the means of two sets of scores. The findings of this study show a significant relationship between locus control and achievement of high school students. The findings can be used by EFL teachers and syllabus designers. Keywords: locus of control; high school students; language achievement; internals; externals

  9. Breeding tropical forages

    Directory of Open Access Journals (Sweden)

    L Jank

    2011-01-01

    Full Text Available Brazil has the largest commercial beef cattle herd and is the main beef exporter in the world. Cultivated pastures arethe basis for the Brazilian beef production, and occupy an area of 101.4 million hectares. However, very few forage cultivars arecommercially available, and the majority of these are of apomictic reproduction, thus genetically homogeneous. Tropical foragebreeding is at its infancy, but much investment and efforts have been applied in the last three decades and some new cultivars havebeen released. In this paper, origin of different species, modes of reproduction, breeding programs and targets are discussed andthe resulting new cultivars released are presented.

  10. Balancing Dreams and Realities: The College Choice Process for High-Achieving Latinas

    Science.gov (United States)

    Hernández, Ebelia

    2015-01-01

    This study's narratives of 17 high-achieving Latinas revealed how their college choice was a constant balancing of individual and family expectations, being "close, but far enough away," and "getting your money's worth." With the use of critical race theory, further analysis revealed the influence of "familismo" on…

  11. Teaching Practices in Grade 5 Mathematics Classrooms with High-Achieving English Learner Students

    Science.gov (United States)

    Merritt, Eileen G.; Palacios, Natalia; Banse, Holland; Rimm-Kaufman, Sara E.; Leis, Micela

    2017-01-01

    Teachers need more clarity about effective teaching practices as they strive to help their low-achieving students understand mathematics. Our study describes the instructional practices used by two teachers who, by value-added metrics, would be considered "highly effective teachers" in classrooms with a majority of students who were…

  12. Filial Piety and Academic Motivation: High-Achieving Students in an International School in South Korea

    Science.gov (United States)

    Tam, Jonathan

    2016-01-01

    This study uses self-determination theory to explore the mechanisms of filial piety in the academic motivation of eight high-achieving secondary school seniors at an international school in South Korea, resulting in several findings. First, the students attributed their parents' values and expectations as a major source of the students'…

  13. Experiencing More Mathematics Anxiety than Expected? Contrasting Trait and State Anxiety in High Achieving Students

    Science.gov (United States)

    Roos, A.-L.; Bieg, M.; Goetz, T.; Frenzel, A. C.; Taxer, J.; Zeidner, M.

    2015-01-01

    This study examined mathematics anxiety among high and low achieving students (N = 237, grades 9 and 10) by contrasting trait (habitual) and state (momentary) assessments of anxiety. Previous studies have found that trait anxiety measures are typically rated higher than state measures. Furthermore, the academic self-concept has been identified to…

  14. Achievement, School Integration, and Self-Efficacy in Single-Sex and Coeducational Parochial High Schools

    Science.gov (United States)

    Micucci, Kara Hanson

    2014-01-01

    A structural model for prior achievement, school integration, and self-efficacy was developed using Tinto's theory of student attrition and Bandura's self-efficacy theory. The model was tested and revised using a sample of 1,452 males and females from single-sex and coeducational parochial high schools. Results indicated that the theoretically…

  15. What Goes into High Educational and Occupational Achievement? Education, Brains, Hard Work, Networks, and Other Factors

    Science.gov (United States)

    Wai, Jonathan; Rindermann, Heiner

    2017-01-01

    There are many factors that go into high educational and occupational achievement, including hard work, motivation, and luck. But how important is talent? Specifically, how likely were global innovators and leaders intellectually talented or gifted when younger? This paper reviews retrospective data on multiple US samples (Total N = 11,745),…

  16. Communication Satisfaction, Organizational Citizenship Behavior and the Relationship to Student Achievement in High Schools

    Science.gov (United States)

    Blanchard, Gayle A.

    2012-01-01

    This study used a correlational design that allowed the researcher to examine the relationship among communication satisfaction, organizational citizenship behaviors (OCB) and student achievement. High school teachers were surveyed from a convenience sample of 12 school districts in Arizona. Established instruments were used to survey teachers'…

  17. Spatial Experiences of High Academic Achievers: Insights from a Developmental Perspective

    Science.gov (United States)

    Weckbacher, Lisa Marie; Okamoto, Yukari

    2012-01-01

    The study explored the relationship between types of spatial experiences and spatial abilities among 13- to 14-year-old high academic achievers. Each participant completed two spatial tasks and a survey assessing favored spatial activities across five categories (computers, toys, sports, music, and art) and three developmental periods (early…

  18. Growing into Equity: Professional Learning and Personalization in High-Achieving Schools

    Science.gov (United States)

    Gleason, Sonia Caus; Gerzon, Nancy

    2013-01-01

    What makes a Title I school high-achieving, and what can we all learn from that experience? Professional learning and leadership that supports personalized instruction makes the difference, as captured in the ground-breaking research of authors Sonia Caus Gleason and Nancy Gerzon. This illuminating book shows how four outstanding schools are…

  19. Social Media Use, Loneliness, and Academic Achievement: A Correlational Study with Urban High School Students

    Science.gov (United States)

    Neto, Roque; Golz, Nancy; Polega, Meaghan

    2015-01-01

    This study explored the association between social media use, loneliness, and academic achievement in high school students and identified the demographic characteristics associated with these three elements. This study also aimed to identify the percentage of variance in loneliness accounted for by social media use and GPA. Participants were 345…

  20. The Effects of Alcohol Use on Academic Achievement in High School

    Science.gov (United States)

    Balsa, Ana I.; Giuliano, Laura M.; French, Michael T.

    2011-01-01

    This paper examines the effects of alcohol use on high school students' quality of learning. We estimate fixed-effects models using data from the National Longitudinal Study of Adolescent Health. Our primary measure of academic achievement is the student's grade point average (GPA) abstracted from official school transcripts. We find that…

  1. Balancing Dreams and Realities: The College Choice Process for High-Achieving Latinas

    Science.gov (United States)

    Hernández, Ebelia

    2015-01-01

    This study's narratives of 17 high-achieving Latinas revealed how their college choice was a constant balancing of individual and family expectations, being "close, but far enough away," and "getting your money's worth." With the use of critical race theory, further analysis revealed the influence of "familismo" on…

  2. One-to-One Computing and Student Achievement in Ohio High Schools

    Science.gov (United States)

    Williams, Nancy L.; Larwin, Karen H.

    2016-01-01

    This study explores the impact of one-to-one computing on student achievement in Ohio high schools as measured by performance on the Ohio Graduation Test (OGT). The sample included 24 treatment schools that were individually paired with a similar control school. An interrupted time series methodology was deployed to examine OGT data over a period…

  3. Communication Satisfaction, Organizational Citizenship Behavior and the Relationship to Student Achievement in High Schools

    Science.gov (United States)

    Blanchard, Gayle A.

    2012-01-01

    This study used a correlational design that allowed the researcher to examine the relationship among communication satisfaction, organizational citizenship behaviors (OCB) and student achievement. High school teachers were surveyed from a convenience sample of 12 school districts in Arizona. Established instruments were used to survey…

  4. Obesity, High-Calorie Food Intake, and Academic Achievement Trends among U.S. School Children

    Science.gov (United States)

    Li, Jian; O'Connell, Ann A.

    2012-01-01

    The authors investigated children's self-reported high-calorie food intake in Grade 5 and its relationship to trends in obesity status and academic achievement over the first 6 years of school. They used 3-level hierarchical linear models in the large-scale database (the Early Childhood Longitudinal Study--Kindergarten Cohort). Findings indicated…

  5. Spatial Experiences of High Academic Achievers: Insights from a Developmental Perspective

    Science.gov (United States)

    Weckbacher, Lisa Marie; Okamoto, Yukari

    2012-01-01

    The study explored the relationship between types of spatial experiences and spatial abilities among 13- to 14-year-old high academic achievers. Each participant completed two spatial tasks and a survey assessing favored spatial activities across five categories (computers, toys, sports, music, and art) and three developmental periods (early…

  6. Effects of Part-Time Work on School Achievement During High School

    Science.gov (United States)

    Singh, Kusum; Chang, Mido; Dika, Sandra

    2007-01-01

    The authors explored the effects of part-time work on school achievement during high school. To estimate the true effects of part-time work on school grades, the authors included family background, students' educational aspirations, and school engagement as controls. Although a substantial literature exists on the relationship of part-time work…

  7. Emotional Intelligence and Academic Achievement of High School Students in Kanyakumari District

    Science.gov (United States)

    Lawrence, A. S. Arul; Deepa, T.

    2013-01-01

    The objective of the study is to find the significant relationship between emotional intelligence and academic achievement of high school students with reference to the background variables. Survey method was employed. Two tools are used in this study namely self-made Trait Emotional Intelligence Questionnaire Short Form (TEIQue SF) and the…

  8. Examining the Predictive Power of Autonomy and Self-Evaluation on High School Students' Language Achievement

    Science.gov (United States)

    Yuksel, Ismail; Toker, Yalcin

    2013-01-01

    This study aims to determine language learners' autonomy, self-evaluation levels and to examine the predictive power of these two variables on language achievement. The study was designed as mixed method design and was conducted with 108 high school students. Data were collected through an autonomy scale, a self-evaluation scale, schools record on…

  9. Perfectionism in High-Ability Students: Relational Precursors and Influences on Achievement Motivation

    Science.gov (United States)

    Speirs Neumeister, Kristie L.; Finch, Holmes

    2006-01-01

    The purpose of the present study was to create and test a model that (a) illustrated variables influencing the development of perfectionism, and (b) demonstrated how different types of perfectionism may influence the achievement goals of high-ability students. Using a multiple groups path analysis, the researchers found that parenting style was…

  10. Effect of Textbook Readability on Student Achievement in High School Chemistry.

    Science.gov (United States)

    Rapp, D. Neil

    2001-01-01

    Notes the readability level of many high school chemistry textbooks is far above students' reading levels. Conducts two separate studies, making every effort to keep the two classes as similar as possible in all aspects except text. Finds strong evidence that changing the chemistry textbook resulted in an increase in student achievement. Suggests…

  11. What Attracts High-Achieving Socioeconomically Disadvantaged Students to the Physical Sciences and Engineering?

    Science.gov (United States)

    Conrad, Sarah; Canetto, Silvia Sara; MacPhee, David; Farro, Samantha

    2009-01-01

    Socioeconomically disadvantaged (SED) students are less likely to major in physical sciences or engineering. To guide recruitment and retention of a diversity of talent, this study examined what attracts high-achieving SED students to these fields. Participants were 50 undergraduates majoring in physical sciences or engineering enrolled in the…

  12. Being Labeled "Nerd": Factors that Influence the Social Acceptance of High-Achieving Students

    Science.gov (United States)

    Rentzsch, Katrin; Schutz, Astrid; Schroder-Abe, Michela

    2011-01-01

    The present investigation addresses the question of whether certain factors can protect high-achieving students at risk for being labeled a nerd against devaluation. In 2 studies, 125 and 317 students from Grade 8 evaluated vignettes describing average students and students who were called "nerds." Results indicate that being modest…

  13. Antecedent and Concurrent Psychosocial Skills That Support High Levels of Achievement within Talent Domains

    Science.gov (United States)

    Olszewski-Kubilius, Paula; Subotnik, Rena F.; Worrell, Frank C.

    2015-01-01

    Motivation and emotional regulation are important for the sustained focused study and practice required for high levels of achievement and creative productivity in adulthood. Using the talent development model proposed by the authors as a framework, the authors discuss several important psychosocial skills based on the psychological research…

  14. Foraging strategy quick response to temperature of Messor barbarus (Hymenoptera: Formicidae) in Mediterranean environments.

    Science.gov (United States)

    Doblas-Miranda, Enrique; Reyes-López, Joaquín

    2008-08-01

    Animals principally forage to try to maximize energy intake per unit of feeding time, developing different foraging strategies. Temperature effects on foraging have been observed in diverse ant species; these effects are limited to the duration of foraging or the number of foragers involved. The harvester ant Messor barbarus L. 1767 has a specialized foraging strategy that consists in the formation of worker trails. Because of the high permeability of their body integument, we presume that the length, shape, and type of foraging trails of M. barbarus must be affected by temperature conditions. From mid-June to mid-August 1999, we tested the effect on these trail characteristics in a Mediterranean forest. We found that thermal stress force ants to use a foraging pattern based on the variation of the workers trail structure. Ants exploit earlier well-known sources using long physical trails, but as temperatures increases throughout the morning, foragers reduce the length of the foraging column gradually, looking for alternative food sources in nonphysical trails. This study shows that animal forage can be highly adaptable and versatile in environments with high daily variations.

  15. The role of teachers at university : what do high achiever students look for?

    OpenAIRE

    Monteiro, Sílvia; Almeida, Leandro S.; Vasconcelos, Rosa

    2012-01-01

    The perceptions of students about their teachers have interested the academic and scientific community, regarding the improvement of the quality of higher education. This paper presents data obtained from interviews conducted with ten high achiever engineering students and focuses on the characteristics of teachers that are highly valued by the participants. Furthermore, the influence of teachers on the development of the students was explored. The data collected describes a set of aspects fr...

  16. High levels of linkage disequilibrium and associations with forage quality at a phenylalanine ammonia-lyase locus in European maize (Zea mays L.) inbreds.

    Science.gov (United States)

    Andersen, Jeppe R; Zein, Imad; Wenzel, Gerhard; Krützfeldt, Birte; Eder, Joachim; Ouzunova, Milena; Lübberstedt, Thomas

    2007-01-01

    Forage quality of maize is influenced by both the content and structure of lignin in the cell wall. Phenylalanine Ammonia-Lyase (PAL) catalyzes the first step in lignin biosynthesis in plants; the deamination of L-phenylalanine to cinnamic acid. Successive enzymatic steps lead to the formation of three monolignols, constituting the complex structure of lignin. We have cloned and sequenced a PAL genomic sequence from 32 maize inbred lines currently employed in forage maize breeding programs in Europe. Low nucleotide diversity and excessive linkage disequilibrium (LD) was identified at this PAL locus, possibly reflecting selective constrains resulting from PAL being the first enzyme in the monolignol, and other, pathways. While the association analysis was affected by extended LD and population structure, several individual polymorphisms were associated with neutral detergent fiber (not considering population structure) and a single polymorphism was associated with in vitro digestibility of organic matter (considering population structure).

  17. Cultivating a Growth Mindset in Students at a High-Achieving High School

    Science.gov (United States)

    Fegley, Alan D.

    2010-01-01

    The purpose of this EPP is to develop a plan for changing the mindset of a large number of Haddonfield Memorial High School (HMHS) students from a fixed mindset to a growth mindset. HMHS is by most conventional measures a high performing school. Typically 100% of the students graduate with 96% of the students attending two or four year colleges…

  18. The Information Search Process of High, Middle, and Low Achieving High School Seniors.

    Science.gov (United States)

    Kuhlthau, Carol C.

    Traditionally, library instruction has been based on the sources in the library and not on the process of seeking information. A new approach to library skills may be needed to enable students to become effective information users. This study investigated the information search process of 140 high school seniors in six high schools. Subjects were…

  19. Cultivating a Growth Mindset in Students at a High-Achieving High School

    Science.gov (United States)

    Fegley, Alan D.

    2010-01-01

    The purpose of this EPP is to develop a plan for changing the mindset of a large number of Haddonfield Memorial High School (HMHS) students from a fixed mindset to a growth mindset. HMHS is by most conventional measures a high performing school. Typically 100% of the students graduate with 96% of the students attending two or four year colleges…

  20. Spatial memory in foraging games.

    Science.gov (United States)

    Kerster, Bryan E; Rhodes, Theo; Kello, Christopher T

    2016-03-01

    Foraging and foraging-like processes are found in spatial navigation, memory, visual search, and many other search functions in human cognition and behavior. Foraging is commonly theorized using either random or correlated movements based on Lévy walks, or a series of decisions to remain or leave proximal areas known as "patches". Neither class of model makes use of spatial memory, but search performance may be enhanced when information about searched and unsearched locations is encoded. A video game was developed to test the role of human spatial memory in a canonical foraging task. Analyses of search trajectories from over 2000 human players yielded evidence that foraging movements were inherently clustered, and that clustering was facilitated by spatial memory cues and influenced by memory for spatial locations of targets found. A simple foraging model is presented in which spatial memory is used to integrate aspects of Lévy-based and patch-based foraging theories to perform a kind of area-restricted search, and thereby enhance performance as search unfolds. Using only two free parameters, the model accounts for a variety of findings that individually support competing theories, but together they argue for the integration of spatial memory into theories of foraging.

  1. Sexual segregation in foraging giraffe

    Science.gov (United States)

    Mramba, Rosemary Peter; Mahenya, Obeid; Siyaya, Annetjie; Mathisen, Karen Marie; Andreassen, Harry Peter; Skarpe, Christina

    2017-02-01

    Sexual segregation in giraffe is known to vary between savannas. In this study, we compared sexual segregation in giraffe in one nutrient-rich savanna, the Serengeti National Park, one nutrient-poor, Mikumi National Park, and one medium rich savanna, Arusha National Park, (from here on referred to just by name) based on effects of sexual size dimorphism and related hypotheses. Data were collected in the wet and dry seasons, by driving road transects and making visual observations of browsing giraffe. Additional data were collected from literature (plant chemistry; mammal communities). There was a noticeable difference in browsing by females and males and in browsing between the three savannas. Females browsed a higher diversity of tree species in Serengeti whereas males browsed a higher diversity in Arusha, while the diversity of species browsed in Mikumi was high and about the same in both sexes. Females selected for high concentrations of nitrogen and low concentrations of tannins and phenolics compared to males in Serengeti but selection in Mikumi was more complex. Males browsed higher in the canopy than females in all sites, but the browsing height was generally higher in Serengeti than Mikumi and Arusha. Season had an effect on the browsing height independent of sex in Mikumi, where giraffes browsed higher in the dry season compared to the wet season. Males spent more time browsing per tree compared to females in all three sites; however, browsing time in Mikumi was also affected by season, where giraffes had longer browsing bouts in the wet season compared to the dry season. We suggest that sexual differences in forage requirement and in foraging interacts with differences in tree chemistry and in competing herbivore communities between nutrient rich and nutrient poor savanna in shaping the sexual segregation.

  2. Psychosocial aspects and management of evaluation in secondary high and low achievement

    Directory of Open Access Journals (Sweden)

    Alicia Rivera Morales

    2017-01-01

    Full Text Available This article describes a segment of a broader study of mixed cut occurs. In this space only part of the qualitative analysis is recovered around the psychosocial aspects that influence the management of the evaluation results from the application of semi-structured interviews and focus groups with 80 senior secondary schools with high and low achievement located in four states of Mexico: Sonora, Durango, Mexico City and Oaxaca. The findings are presented from categories they consider the meaning, beliefs and expectations about evaluation and how these aspects influence the actions of the directors of the schools studied. Polarized cases allow, in their contrasts, identify processes and factors that mark the differences or similarities between them. Thus it was found that school principals low achievement hope to change the attitude of teachers towards the assessment, expect supervisors to monitor teachers and external support (specialists that indicate how to evaluate them. Moreover, the idea that a school with high achievement is an organization that promotes the participation director, has high expectations of students and teachers, its management system and decision-making can achieve the objectives set, and reasserts Assessment proposes actions that seek continuous improvement.

  3. Leaf transcriptome of two highly divergent genotypes of Urochloa humidicola (Poaceae), a tropical polyploid forage grass adapted to acidic soils and temporary flooding areas.

    Science.gov (United States)

    Vigna, Bianca Baccili Zanotto; de Oliveira, Fernanda Ancelmo; de Toledo-Silva, Guilherme; da Silva, Carla Cristina; do Valle, Cacilda Borges; de Souza, Anete Pereira

    2016-11-11

    Urochloa humidicola (Koronivia grass) is a polyploid (6x to 9x) species that is used as forage in the tropics. Facultative apospory apomixis is present in most of the genotypes of this species, although one individual has been described as sexual. Molecular studies have been restricted to molecular marker approaches for genetic diversity estimations and linkage map construction. The objectives of the present study were to describe and compare the leaf transcriptome of two important genotypes that are highly divergent in terms of their phenotypes and reproduction modes: the sexual BH031 and the aposporous apomictic cultivar BRS Tupi. We sequenced the leaf transcriptome of Koronivia grass using an Illumina GAIIx system, which produced 13.09 Gb of data that consisted of 163,575,526 paired-end reads between the two libraries. We de novo-assembled 76,196 transcripts with an average length of 1,152 bp and filtered 35,093 non-redundant unigenes. A similarity search against the non-redundant National Center of Biotechnology Information (NCBI) protein database returned 65 % hits. We annotated 24,133 unigenes in the Phytozome database and 14,082 unigenes in the UniProtKB/Swiss-Prot database, assigned 108,334 gene ontology terms to 17,255 unigenes and identified 5,324 unigenes in 327 known metabolic pathways. Comparisons with other grasses via a reciprocal BLAST search revealed a larger number of orthologous genes for the Panicum species. The unigenes were involved in C4 photosynthesis, lignocellulose biosynthesis and flooding stress responses. A search for functional molecular markers revealed 4,489 microsatellites and 560,298 single nucleotide polymorphisms (SNPs). A quantitative real-time PCR analysis validated the RNA-seq expression analysis and allowed for the identification of transcriptomic differences between the two evaluated genotypes. Moreover, 192 unannotated sequences were classified as containing complete open reading frames, suggesting that the new

  4. Implementation and control of electrolysers to achieve high penetrations of renewable power

    Energy Technology Data Exchange (ETDEWEB)

    Troncoso, E.; Newborough, M. [ITM Power plc, Orkney House, Great Chesterford Court, Great Chesterford, Saffron Walden CB10 1PF (United Kingdom)

    2007-09-15

    The mass deployment of electrolysers, within a power system serving a region of high wind resource, as the enabling mechanism for achieving five key objectives is assessed (that is: a very high installed capacity of wind power plant (WPP); zero wind curtailment during times of low demand; a very high load factor for thermal power plant; an electricity supply of low-carbon intensity; and a hydrogen supply of low-carbon intensity). Three electrolyser implementation cases were simulated for three days characterised mainly by wind availability and emphasis was placed on maximizing the smoothness of the load profile (LF) applied to thermal power plant. If zero-carbon hydrogen is to be produced a daily load factor for thermal power plant of 90% is the upper limit, but load factors of up to 100% are achievable if a carbon intensity of 3kgCO{sub 2}/kgH{sub 2} is permitted. For wind penetrations exceeding approximately 30% of system maximum demand, the electrolyser stock must include implementations close to WPP if curtailment is to be avoided. To achieve very high wind penetrations and very high load factors for thermal power plant requires a large stock of electrolysers - for the system investigated approximately 1.1 MW of electrolyser capacity is required per installed MW of wind power. (author)

  5. Experimental Study of the Dynamics of Foraging Ants

    Science.gov (United States)

    Walker, J. I.; Fetzner, R. P.; Baxter, G. W.

    2006-03-01

    We study the search paths of foraging ants in order to describe their behavior mathematically. Ants have become popular as simple agents in models of artificial life. Here, the ant is presented the problem of finding food when no food cues are present. In this experiment, individual ants (Formicinae lasius flavus) are allowed to forage on a two-dimensional textured surface in the absence of a food source. The position of the ant as a function of time is determined with a high resolution digital camera. The scaling properties of the resulting foraging paths compare favorably with those of certain types of random walk.

  6. Relationship of constructivist learning environment to student attitudes and achievement in high school mathematics and science

    Science.gov (United States)

    Dethlefs, Theresa Marie

    This study investigated the relationship of constructivist learning environment and standards-based teaching practices to student achievement and attitudes (self-efficacy, intrinsic value, and learning strategies) in Algebra and Biology. Further, these relationships were examined as a function of student gender and prior achievement. A purposive sample of 804 high school students enrolled in Biology I, Algebra I, or Advanced Algebra was selected for inclusion in this study. Although the dimensions of constructivist learning environment that contributed to predicting student achievement and attitudes varied by content area and criterion, the results of the present study generally provide strong support for a positive relationship between constructivist learning environment and student attitudes, but little support for a direct relationship to student achievement. Teacher reports of overall constructivist learning environment were not correlated with achievement or attitudes. Observer reports of constructivist learning environment were correlated with student intrinsic value and learning strategies. Student reports of constructivist learning environment were correlated with all three attitude measures. Multiple regression findings showed that neither overall constructivist learning environment nor standards-based teaching practices predicted achievement in any of the content areas. Overall constructivist learning environment and standards-based teaching practices were significant positive predictors of student intrinsic value and learning strategies in all three content areas, after controlling for student and classroom demographic variables. Overall constructivist learning environment and standards-based teaching practices were also significant positive predictors of self-efficacy in Algebra 1. In addition, standards-based teaching practices was a significant positive predictor of student self-efficacy in Biology. No specific dimensions of constructivist learning

  7. Computer-Based Drill and Practice in Arithmetic: Widening the Gap between High- and Low-Achieving Students.

    Science.gov (United States)

    Hativa, Nira

    1988-01-01

    The differential effects of computer-assisted instruction for high-achieving and low-achieving students were examined for seven elementary students of varied background. Higher-achieving students were more able to adjust to the requirements of computer work and to derive benefit from it than were lower-achieving students. Implications for teaching…

  8. Achievement Motivation of the High School Students: A Case Study among Different Communities of Goalpara District of Assam

    Science.gov (United States)

    Sarangi, C.

    2015-01-01

    Achievement motivation is a consistent striving force of an individual to achieve success to a certain standard of excellence in competing situation. In this study an attempt was made to study the effect of achievement motivation on the academic achievement of the high school students of tribal and non tribal communities in relation to their sex…

  9. The impact of including children with intellectual disability in general education classrooms on the academic achievement of their low-, average-, and high-achieving peers.

    Science.gov (United States)

    Sermier Dessemontet, Rachel; Bless, Gérard

    2013-03-01

    This study aimed at assessing the impact of including children with intellectual disability (ID) in general education classrooms with support on the academic achievement of their low-, average-, and high-achieving peers without disability. A quasi-experimental study was conducted with an experimental group of 202 pupils from classrooms with an included child with mild or moderate ID, and a control group of 202 pupils from classrooms with no included children with special educational needs (matched pairs sample). The progress of these 2 groups in their academic achievement was compared over a period of 1 school year. No significant difference was found in the progress of the low-, average-, or high-achieving pupils from classrooms with or without inclusion. The results suggest that including children with ID in primary general education classrooms with support does not have a negative impact on the progress of pupils without disability.

  10. The role of chronotype, gender, test anxiety, and conscientiousness in academic achievement of high school students.

    Science.gov (United States)

    Rahafar, Arash; Maghsudloo, Mahdis; Farhangnia, Sajedeh; Vollmer, Christian; Randler, Christoph

    2016-01-01

    Previous findings have demonstrated that chronotype (morningness/intermediate/eveningness) is correlated with cognitive functions, that is, people show higher mental performance when they do a test at their preferred time of day. Empirical studies found a relationship between morningness and higher learning achievement at school and university. However, only a few of them controlled for other moderating and mediating variables. In this study, we included chronotype, gender, conscientiousness and test anxiety in a structural equation model (SEM) with grade point average (GPA) as academic achievement outcome. Participants were 158 high school students and results revealed that boys and girls differed in GPA and test anxiety significantly, with girls reporting better grades and higher test anxiety. Moreover, there was a positive correlation between conscientiousness and GPA (r = 0.17) and morningness (r = 0.29), respectively, and a negative correlation between conscientiousness and test anxiety (r = -0.22). The SEM demonstrated that gender was the strongest predictor of academic achievement. Lower test anxiety predicted higher GPA in girls but not in boys. Additionally, chronotype as moderator revealed a significant association between gender and GPA for evening types and intermediate types, while intermediate types showed a significant relationship between test anxiety and GPA. Our results suggest that gender is an essential predictor of academic achievement even stronger than low or absent test anxiety. Future studies are needed to explore how gender and chronotype act together in a longitudinal panel design and how chronotype is mediated by conscientiousness in the prediction of academic achievement.

  11. High fat diet promotes achievement of peak bone mass in young rats

    Energy Technology Data Exchange (ETDEWEB)

    Malvi, Parmanand; Piprode, Vikrant; Chaube, Balkrishna; Pote, Satish T. [National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune 411 007 (India); Mittal, Monika; Chattopadhyay, Naibedya [Division of Endocrinology and Center for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Jankipuram Extension, Sitapur Road, Lucknow 226 031 (India); Wani, Mohan R. [National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune 411 007 (India); Bhat, Manoj Kumar, E-mail: manojkbhat@nccs.res.in [National Centre for Cell Science, Savitribai Phule Pune University Campus, Ganeshkhind, Pune 411 007 (India)

    2014-12-05

    Highlights: • High fat diet helps in achieving peak bone mass at younger age. • Shifting from high fat to normal diet normalizes obese parameters. • Bone parameters are sustained even after withdrawal of high fat diet. - Abstract: The relationship between obesity and bone is complex. Epidemiological studies demonstrate positive as well as negative correlation between obesity and bone health. In the present study, we investigated the impact of high fat diet-induced obesity on peak bone mass. After 9 months of feeding young rats with high fat diet, we observed obesity phenotype in rats with increased body weight, fat mass, serum triglycerides and cholesterol. There were significant increases in serum total alkaline phosphatase, bone mineral density and bone mineral content. By micro-computed tomography (μ-CT), we observed a trend of better trabecular bones with respect to their microarchitecture and geometry. This indicated that high fat diet helps in achieving peak bone mass and microstructure at younger age. We subsequently shifted rats from high fat diet to normal diet for 6 months and evaluated bone/obesity parameters. It was observed that after shifting rats from high fat diet to normal diet, fat mass, serum triglycerides and cholesterol were significantly decreased. Interestingly, the gain in bone mineral density, bone mineral content and trabecular bone parameters by HFD was retained even after body weight and obesity were normalized. These results suggest that fat rich diet during growth could accelerate achievement of peak bone mass that is sustainable even after withdrawal of high fat diet.

  12. Personality, foraging and fitness consequences in a long lived seabird.

    Directory of Open Access Journals (Sweden)

    Samantha C Patrick

    Full Text Available While personality differences in animals are defined as consistent behavioural variation between individuals, the widely studied field of foraging specialisation in marine vertebrates has rarely been addressed within this framework. However there is much overlap between the two fields, both aiming to measure the causes and consequences of consistent individual behaviour. Here for the first time we use both a classic measure of personality, the response to a novel object, and an estimate of foraging strategy, derived from GPS data, to examine individual personality differences in black browed albatross and their consequences for fitness. First, we examine the repeatability of personality scores and link these to variation in foraging habitat. Bolder individuals forage nearer the colony, in shallower regions, whereas shyer birds travel further from the colony, and fed in deeper oceanic waters. Interestingly, neither personality score predicted a bird's overlap with fisheries. Second, we show that both personality scores are correlated with fitness consequences, dependent on sex and year quality. Our data suggest that shyer males and bolder females have higher fitness, but the strength of this relationship depends on year quality. Females who forage further from the colony have higher breeding success in poor quality years, whereas males foraging close to the colony always have higher fitness. Together these results highlight the potential importance of personality variation in seabirds and that the fitness consequences of boldness and foraging strategy may be highly sex dependent.

  13. Toward achieving flexible and high sensitivity hexagonal boron nitride neutron detectors

    Science.gov (United States)

    Maity, A.; Grenadier, S. J.; Li, J.; Lin, J. Y.; Jiang, H. X.

    2017-07-01

    Hexagonal boron nitride (h-BN) detectors have demonstrated the highest thermal neutron detection efficiency to date among solid-state neutron detectors at about 51%. We report here the realization of h-BN neutron detectors possessing one order of magnitude enhancement in the detection area but maintaining an equal level of detection efficiency of previous achievement. These 3 mm × 3 mm detectors were fabricated from 50 μm thick freestanding and flexible 10B enriched h-BN (h-10BN) films, grown by metal organic chemical vapor deposition followed by mechanical separation from sapphire substrates. Mobility-lifetime results suggested that holes are the majority carriers in unintentionally doped h-BN. The detectors were tested under thermal neutron irradiation from californium-252 (252Cf) moderated by a high density polyethylene moderator. A thermal neutron detection efficiency of ˜53% was achieved at a bias voltage of 200 V. Conforming to traditional solid-state detectors, the realization of h-BN epilayers with enhanced electrical transport properties is the key to enable scaling up the device sizes. More specifically, the present results revealed that achieving an electrical resistivity of greater than 1014 Ωṡcm and a leakage current density of below 3 × 10-10 A/cm2 is needed to fabricate large area h-BN detectors and provided guidance for achieving high sensitivity solid state neutron detectors based on h-BN.

  14. When high achievers and low achievers work in the same group: the roles of group heterogeneity and processes in project-based learning.

    Science.gov (United States)

    Cheng, Rebecca Wing-yi; Lam, Shui-fong; Chan, Joanne Chung-yan

    2008-06-01

    There has been an ongoing debate about the inconsistent effects of heterogeneous ability grouping on students in small group work such as project-based learning. The present research investigated the roles of group heterogeneity and processes in project-based learning. At the student level, we examined the interaction effect between students' within-group achievement and group processes on their self- and collective efficacy. At the group level, we examined how group heterogeneity was associated with the average self- and collective efficacy reported by the groups. The participants were 1,921 Hong Kong secondary students in 367 project-based learning groups. Student achievement was determined by school examination marks. Group processes, self-efficacy and collective efficacy were measured by a student-report questionnaire. Hierarchical linear modelling was used to analyse the nested data. When individual students in each group were taken as the unit of analysis, results indicated an interaction effect of group processes and students' within-group achievement on the discrepancy between collective- and self-efficacy. When compared with low achievers, high achievers reported lower collective efficacy than self-efficacy when group processes were of low quality. However, both low and high achievers reported higher collective efficacy than self-efficacy when group processes were of high quality. With 367 groups taken as the unit of analysis, the results showed that group heterogeneity, group gender composition and group size were not related to the discrepancy between collective- and self-efficacy reported by the students. Group heterogeneity was not a determinant factor in students' learning efficacy. Instead, the quality of group processes played a pivotal role because both high and low achievers were able to benefit when group processes were of high quality.

  15. Solvent additive to achieve highly ordered nanostructural semicrystalline DPP copolymers: toward a high charge carrier mobility.

    Science.gov (United States)

    An, Tae Kyu; Kang, Il; Yun, Hui-jun; Cha, Hyojung; Hwang, Jihun; Park, Seonuk; Kim, Jiye; Kim, Yu Jin; Chung, Dae Sung; Kwon, Soon-Ki; Kim, Yun-Hi; Park, Chan Eon

    2013-12-23

    A facile spin-coating method in which a small percentage of the solvent additive, 1-chloronaphthalene (CN), is found to increase the drying time during film deposition, is reported. The field-effect mobility of a PDPPDBTE film cast from a chloroform-CN mixed solution is 0.46 cm(2) V(-1) s(-1). The addition of CN to the chloroform solution facilitates the formation of highly crystalline polymer structures.

  16. The tzero electric sports car : how electric vehicles can achieve both high performance and high efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Brooks, A.N.; Gage, T.B. [AC Propulsion, San Dimas, CA (United States)

    2000-07-01

    The development of a high-performance electric sports car by AC Propulsion was described along with a status report on the progress in developing the product-certified version. The development of the tzero car began in 1996. In-use testing and safety certification of prototypes is currently underway. The tzero is powered by a high-performance induction motor operated at 37 per cent higher peak current than allowed in a standard system since periods of peak power are limited to only a few seconds. The car, which can accelerate from 0 to 60 mph in 4.1 seconds, is considered to be one of the most energy-efficient cars on the road. Since the tzero will likely be sold without subsidy and since the market size for the tzero is expected to be small, in the order of 1000 units per year, it will have to be sold at a high enough price to cover the costs of small-volume production. AC Propulsion is hopeful that it may even be the first electric vehicle to be sold at a profit. Its technology and image are expected to present examples for other electric vehicles. The paper also included a comprehensive technical description of the car and its systems, such as the power electronics unit, traction converter, charger, auxiliary power supply, 12V battery, recharge interface, battery pack, battery modules and powertrain control. 4 tabs., 15 figs.

  17. Attention in Urban Foraging

    Directory of Open Access Journals (Sweden)

    Malcolm McCullough

    2013-05-01

    Full Text Available This position paper argues how there has to be much more to smart city learning than just wayshowing, and something better as augmented reality than covering the world with instructions. Attention has become something for many people to know better in an age of information superabundance. Embodied cognition explains how the work-ings of attention are not solely a foreground task, as if attention is something to pay. As digital media appear in ever more formats and contexts, their hybrids with physical form increasing influence how habitual engagement with persistent situations creates learning. Ambient information can just add to the distraction by multitasking, or it can support more favorable processes of shifting among different kinds of information with a particular intent. As one word for this latter process, foraging deserves more consideration in smart city learning

  18. Anaerobic co-digestion of forage radish and dairy manure in complete mix digesters

    Science.gov (United States)

    Farmers are increasingly using forage radish as a winter cover crop to achieve multiple soil and environmental benefits. In this study, pilot-scale mixed digesters were used to quantify methane (CH4) and hydrogen sulfide (H2S) production when using forage radish, a sulfur-rich cover crop, as a co-d...

  19. Colony variation in the collective regulation of foraging by harvester ants

    Science.gov (United States)

    Guetz, Adam; Greene, Michael J.; Holmes, Susan

    2011-01-01

    This study investigates variation in collective behavior in a natural population of colonies of the harvester ant, Pogonomyrmex barbatus. Harvester ant colonies regulate foraging activity to adjust to current food availability; the rate at which inactive foragers leave the nest on the next trip depends on the rate at which successful foragers return with food. This study investigates differences among colonies in foraging activity and how these differences are associated with variation among colonies in the regulation of foraging. Colonies differ in the baseline rate at which patrollers leave the nest, without stimulation from returning ants. This baseline rate predicts a colony's foraging activity, suggesting there is a colony-specific activity level that influences how quickly any ant leaves the nest. When a colony's foraging activity is high, the colony is more likely to regulate foraging. Moreover, colonies differ in the propensity to adjust the rate of outgoing foragers to the rate of forager return. Naturally occurring variation in the regulation of foraging may lead to variation in colony survival and reproductive success. PMID:22479133

  20. Colony variation in the collective regulation of foraging by harvester ants.

    Science.gov (United States)

    Gordon, Deborah M; Guetz, Adam; Greene, Michael J; Holmes, Susan

    2011-03-01

    This study investigates variation in collective behavior in a natural population of colonies of the harvester ant, Pogonomyrmex barbatus. Harvester ant colonies regulate foraging activity to adjust to current food availability; the rate at which inactive foragers leave the nest on the next trip depends on the rate at which successful foragers return with food. This study investigates differences among colonies in foraging activity and how these differences are associated with variation among colonies in the regulation of foraging. Colonies differ in the baseline rate at which patrollers leave the nest, without stimulation from returning ants. This baseline rate predicts a colony's foraging activity, suggesting there is a colony-specific activity level that influences how quickly any ant leaves the nest. When a colony's foraging activity is high, the colony is more likely to regulate foraging. Moreover, colonies differ in the propensity to adjust the rate of outgoing foragers to the rate of forager return. Naturally occurring variation in the regulation of foraging may lead to variation in colony survival and reproductive success.

  1. The high heritability of educational achievement reflects many genetically influenced traits, not just intelligence.

    Science.gov (United States)

    Krapohl, Eva; Rimfeld, Kaili; Shakeshaft, Nicholas G; Trzaskowski, Maciej; McMillan, Andrew; Pingault, Jean-Baptiste; Asbury, Kathryn; Harlaar, Nicole; Kovas, Yulia; Dale, Philip S; Plomin, Robert

    2014-10-21

    Because educational achievement at the end of compulsory schooling represents a major tipping point in life, understanding its causes and correlates is important for individual children, their families, and society. Here we identify the general ingredients of educational achievement using a multivariate design that goes beyond intelligence to consider a wide range of predictors, such as self-efficacy, personality, and behavior problems, to assess their independent and joint contributions to educational achievement. We use a genetically sensitive design to address the question of why educational achievement is so highly heritable. We focus on the results of a United Kingdom-wide examination, the General Certificate of Secondary Education (GCSE), which is administered at the end of compulsory education at age 16. GCSE scores were obtained for 13,306 twins at age 16, whom we also assessed contemporaneously on 83 scales that were condensed to nine broad psychological domains, including intelligence, self-efficacy, personality, well-being, and behavior problems. The mean of GCSE core subjects (English, mathematics, science) is more heritable (62%) than the nine predictor domains (35-58%). Each of the domains correlates significantly with GCSE results, and these correlations are largely mediated genetically. The main finding is that, although intelligence accounts for more of the heritability of GCSE than any other single domain, the other domains collectively account for about as much GCSE heritability as intelligence. Together with intelligence, these domains account for 75% of the heritability of GCSE. We conclude that the high heritability of educational achievement reflects many genetically influenced traits, not just intelligence.

  2. Achieving high performance polymer optoelectronic devices for high efficiency, long lifetime and low fabrication cost

    Science.gov (United States)

    Huang, Jinsong

    This thesis described three types of organic optoelectronic devices: polymer light emitting diodes (PLED), polymer photovoltaic solar cell, and organic photo detector. The research in this work focuses improving their performance including device efficiency, operation lifetime simplifying fabrication process. With further understanding in PLED device physics, we come up new device operation model and improved device architecture design. This new method is closely related to understanding of the science and physics at organic/metal oxide and metal oxide/metal interface. In our new device design, both material and interface are considered in order to confine and balance all injected carriers, which has been demonstrated very be successful in increasing device efficiency. We created two world records in device efficiency: 18 lm/W for white emission fluorescence PLED, 22 lm/W for red emission phosphorescence PLED. Slow solvent drying process has been demonstrated to significantly increase device efficiency in poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C 61-butyric acid methyl ester (PCBM) mixture polymer solar cell. From the mobility study by time of flight, the increase of efficiency can be well correlated to the improved carrier transport property due to P3HT crystallization during slow solvent drying. And it is found that, similar to PLED, balanced carrier mobility is essential in high efficient polymer solar cell. There is also a revolution in our device fabrication method. A unique device fabrication method is presented by an electronic glue based lamination process combined with interface modification as a one-step polymer solar cell fabrication process. It can completely skip the thermal evaporation process, and benefit device lifetime by several merits: no air reactive. The device obtained is metal free, semi-transparent, flexible, self-encapsulated, and comparable efficiency with that by regular method. We found the photomultiplication (PM) phenomenon in C

  3. A SIMPLE WAY OF ACHIEVING A HIGH CELL CONCENTRATION IN RECOMBINANT Escherichia coli CULTIVATION

    Directory of Open Access Journals (Sweden)

    Gombert A.K.

    1997-01-01

    Full Text Available Abstract - A cultivation strategy based on some previous knowledge of the metabolism of Escherichia coli BL21 (DE3 pLysS containing the troponin C gene cloned into plasmid pET was developed and applied through the use of simple fermentation equipment and a feed-forward control strategy in order to achieve a high cell concentration ¾ 92 g l-1 dry cell weight ¾ and a high cell productivity ¾ 3.7 g l-1 h-1.

  4. Achieving Hydrogen Storage Goals through High-Strength Fiber Glass - Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hong [PPG Industries, Inc., Cheswick, PA (United States); Johnson, Kenneth I. [PPG Industries, Inc., Cheswick, PA (United States); Newhouse, Norman L. [PPG Industries, Inc., Cheswick, PA (United States)

    2017-06-05

    Led by PPG and partnered with Hexagon Lincoln and Pacific Northwest National Laboratory (PNNL), the team recently carried out a project “Achieving Hydrogen Storage Goals through High-Strength Fiber Glass”. The project was funded by DOE’s Fuel Cell Technologies office within the Office of Energy Efficiency and Renewable Energy, starting on September 1, 2014 as a two-year project to assess technical and commercial feasibilities of manufacturing low-cost, high-strength glass fibers to replace T700 carbon fibers with a goal of reducing the composite total cost by 50% of the existing, commercial 700 bar hydrogen storage tanks used in personal vehicles.

  5. Biological conversion of forage sorghum biomass to ethanol by steam explosion pretreatment and simultaneous hydrolysis and fermentation at high solid content

    Energy Technology Data Exchange (ETDEWEB)

    Manzanares, Paloma; Ballesteros, Ignacio; Negro, Maria Jose; Oliva, Jose Miguel; Gonzalez, Alberto; Ballesteros, Mercedes [Renewable Energy Department-CIEMAT, Biofuels Unit, Madrid (Spain)

    2012-06-15

    In this work, forage sorghum biomass was studied as feedstock for ethanol production by a biological conversion process comprising the steps of hydrothermal steam explosion pretreatment, enzymatic hydrolysis with commercial enzymes, and fermentation with the yeast Saccharomyces cerevisiae. Steam explosion conditions were optimized using a response surface methodology considering temperature (180-230 C) and time (2-10 min). Sugar recovery in the pretreatment and the enzymatic digestibility of the pretreated solid were used to determine the optimum conditions, i.e., 220 C and 7 min. At these conditions, saccharification efficiency attained 89 % of the theoretical and the recovery of xylose in the prehydrolyzate accounted for 35 % of the amount of xylose present in raw material. Then, a simultaneous hydrolysis and fermentation (SSF) process was tested at laboratory scale on the solid fraction of forage sorghum pretreated at optimum condition, in order to evaluate ethanol production. The effect of the enzyme dose and the supplementation with xylanase enzyme of the cellulolytic enzyme cocktail was studied at increasing solid concentration up to 18 % (w/w) in SSF media. Results show good performance of SSF in all consistencies tested with a significant effect of increasing enzyme load in SSF yield and final ethanol concentration. Xylanase supplementation allows increasing solid concentration up to 18 % (w/w) with good SSF performance and final ethanol content of 55 g/l after 4-5 days. Based on this result, about 190 l of ethanol could be obtained from 1 t of untreated forage sorghum, which means a transformation yield of 85 % of the glucose contained in the feedstock. (orig.)

  6. Forage fiber effects on particle size reduction, ruminal stratification, and selective retention in heifers fed highly digestible grass/clover silages

    DEFF Research Database (Denmark)

    Schulze, A.K.S.; Weisbjerg, Martin Riis; Storm, Adam Christian

    2014-01-01

    , chewing activity, and apparent digestibility. Four grass/clover harvests (Mixtures of Lolium perenne, Trifolium pratense, and Trifolium repens) were performed from early May to late August at different maturities, at different regrowth stages, and with different clover proportions, resulting in silages...... measured. Intake of NDF increased linearly from 2.3 to 2.8 kg/d with greater NDF content of forages (P = 0.01), but silages were exposed to similar eating time (P = 0.55) and rumination time per kg NDF (P = 0.35). No linear effect of NDF content was found on proportion of LP in ingested feed boluses (P = 0...

  7. A Study of Gifted High, Moderate, and Low Achievers in Their Personal Characteristics and Attitudes toward School and Teachers

    Science.gov (United States)

    Abu-Hamour, Bashir; Al-Hmouz, Hanan

    2013-01-01

    This study examines the problem of underachievement among gifted high school students. Low achievers were compared to high and moderate achievers on their motivation, self-regulation, and attitudes toward their school and teachers. Participants were all highly able students from grades 10 and 11 in an academically selective gifted high school in…

  8. The Effect of English Learning Anxiety on Iranian High-School Students’ English Language Achievement

    Directory of Open Access Journals (Sweden)

    Sara Atef-Vahid

    2011-10-01

    Full Text Available The present study explored English language learning anxiety among 38 third-year high school students in English classrooms and its relationship with overall English achievement. Students’ foreign language anxiety was surveyed and analyzed using the Foreign Language Classroom Anxiety Scale (Horwitz, Horwitz, & Cope, 1986 [14] and their English achievement was measured through their final standardized English exam administered by the school. The results showed that although some students felt extremely confident and relaxed, however, one-third of the
    students experienced moderate to high-anxiety levels while learning the English language in class. Correlational analysis revealed that the total FLCAS scores had a significantly moderate negative correlation (r=-.0586, p<.01 with the total final English exams scores of the participants. Anxiety was also analyzed according to the four different variables of anxiety (communication anxiety, test anxiety, fear of negative evaluation, English classroom anxiety which were measured by the FLCAS. The results of the Pearson correlational analysis indicated that English achievement was modestly correlated with all four anxiety variables (p<0.01. Of the four types of anxiety, English Classroom anxiety had the highest correlational value. Finally, possible anxiety provoking factors
    leading to these findings are examined and discussed, and some pedagogical implications are proposed.

  9. Students’ High Achievement on Learning Style Preferences in Chinese Department, Binus University

    Directory of Open Access Journals (Sweden)

    Yetty Go

    2013-11-01

    Full Text Available Every student certainly demonstrates different achievement in her/his Chinese language learning process because every student has her/his own individual way to resolve their problems in learning. In learning process, student’s individual differences exist. These differences lead to different learning speed and learning style of the student. The purpose of this study was to investigate the high achievement students’ learning styles. This study was based on Reid’s learning styles theory and also uses Reid’s Perceptual Learning Style Preference Questionnaire (PLSPQ to investigate student’s learning styles. The main finding of this study is that student’s learning style preference is group style. According to student learning style preferences results, students prefer to learn together with others or in group and learn in a more interactive way.

  10. Academic achievement in the high school years: the changing role of school engagement.

    Science.gov (United States)

    Chase, Paul A; Hilliard, Lacey J; Geldhof, G John; Warren, Daniel J A; Lerner, Richard M

    2014-06-01

    School engagement is an important theoretical and practical cornerstone to the promotion of academic accomplishments. This article used a tripartite-behavioral, emotional, and cognitive-model of school engagement to assess the relationship between school engagement and academic success among high school students, and to determine whether a reciprocal relationship exists between these constructs. Data were derived from 710 youth (69% female) who took part in Waves 6 through 8 (Grades 10 through 12) of the 4-H study of positive youth development. Longitudinal confirmatory factor analyses confirmed the invariance of the tripartite model of school engagement. Results of a structural equation model showed that the components of school engagement and academic achievement were mutually predictive and that these predictions varied from grade to grade. Future possibilities for evaluating the relationship between school engagement and academic achievement, as well as the implications for educational policy and practice, are discussed.

  11. The effects of modeling instruction on high school physics academic achievement

    Science.gov (United States)

    Wright, Tiffanie L.

    The purpose of this study was to explore whether Modeling Instruction, compared to traditional lecturing, is an effective instructional method to promote academic achievement in selected high school physics classes at a rural middle Tennessee high school. This study used an ex post facto , quasi-experimental research methodology. The independent variables in this study were the instructional methods of teaching. The treatment variable was Modeling Instruction and the control variable was traditional lecture instruction. The Treatment Group consisted of participants in Physical World Concepts who received Modeling Instruction. The Control Group consisted of participants in Physical Science who received traditional lecture instruction. The dependent variable was gains scores on the Force Concepts Inventory (FCI). The participants for this study were 133 students each in both the Treatment and Control Groups (n = 266), who attended a public, high school in rural middle Tennessee. The participants were administered the Force Concepts Inventory (FCI) prior to being taught the mechanics of physics. The FCI data were entered into the computer-based Statistical Package for the Social Science (SPSS). Two independent samples t-tests were conducted to answer the research questions. There was a statistically significant difference between the treatment and control groups concerning the instructional method. Modeling Instructional methods were found to be effective in increasing the academic achievement of students in high school physics. There was no statistically significant difference between FCI gains scores for gender. Gender was found to have no effect on the academic achievement of students in high school physics classes. However, even though there was not a statistically significant difference, female students' gains scores were higher than male students' gains scores when Modeling Instructional methods of teaching were used. Based on these findings, it is recommended

  12. Alfalfa (Medicago Sativa L As A Promising Forage In Indonesia

    Directory of Open Access Journals (Sweden)

    Sajimin

    2011-06-01

    Full Text Available Alfalfa (Medicago sativa L or Lucerne is a perennial herbaceous legume with superior forage quality. It is the most important forage crop in the world and it was the first domesticated forage crop. Alfalfa is able to fix nitrogen from the air through a symbiotic relationship with Rhizobium bacteria with N production 7.85 – 10.37 g/m2. Its rooting system can reach 4.5 m that allows it to escape drought. Forage production can reach 15.48 tons of dry matter per ha/year and containing 18.0 – 29.1 % crude protein. Plants can live 3 to 12 years depending on climatic conditions and crop varieties. However, alfalfa is not a tropical plant, thus it has not been widely cultivated in Indonesia. The problem of alfalfa cultivation are high pest attacks and competition with weeds. Therefore, alfalfa cultivation requires attention and good management to obtain optimum yield.

  13. Moving to higher ground: Closing the high school science achievement gap

    Science.gov (United States)

    Mebane, Joyce Graham

    The purpose of this study was to examine the perceptions of West High School constituents (students, parents, teachers, administrators, and guidance counselors) about the readiness and interest of African American students at West High School to take Advanced Placement (AP) and International Baccalaureate (IB) science courses as a strategy for closing the achievement gap. This case study utilized individual interviews and questionnaires for data collection. The participants were selected biology students and their parents, teachers, administrators, and guidance counselors at West High School. The results of the study indicated that just over half the students and teachers, most parents, and all guidance counselors thought African American students were prepared to take AP science courses. Only one of the three administrators thought the students were prepared to take AP science courses. Between one-half and two-thirds of the students, parents, teachers, and administrators thought students were interested in taking an AP science course. Only two of the guidance counselors thought there was interest among the African American students in taking AP science courses. The general consensus among the constituents about the readiness and interest of African American students at West High School to take IB science courses was that it is too early in the process to really make definitive statements. West is a prospective IB school and the program is new and not yet in place. Educators at the West High School community must find reasons to expect each student to succeed. Lower expectations often translate into lower academic demands and less rigor in courses. Lower academic demands and less rigor in courses translate into less than adequate performance by students. When teachers and administrators maintain high expectations, they encourage students to aim high rather than slide by with mediocre effort (Lumsden, 1997). As a result of the study, the following suggestions should

  14. Understanding the mathematics and science achievement and growth trajectories of high ability high school students using hierarchical linear modeling

    Science.gov (United States)

    Belen-Ferrer, Bellasanta

    2009-12-01

    This study used longitudinal data and individual, family, and academic-related matriculation variables to examine trends in initial status and growth trajectories in overall academics, mathematics, and science achievement among 224 high ability high school Asian students. Results indicate that females have an advantage in both initial status and growth rates in overall academics and science. None of the family variables entered in the models were found to be significantly related to overall academics grade point average. All available matriculation variables entered into the models explained less than or at most about half the variance in initial achievement status and growth rate in overall academics and science but not in mathematics. These results strongly imply that other factors, notably family and school and/or classroom-related variables, not measured by the ones used in the models could explain the expected variance in initial status and growth rate of the students especially in Mathematics.

  15. Hmong Parental Involvement and Support: A Comparison Between Families of High and Low Achieving High School Seniors

    Directory of Open Access Journals (Sweden)

    Katherine Green

    2009-01-01

    Full Text Available The Hmong are some of the newest refugees who have settled in the United States with population estimates around 300,000. Unfortunately research has shown many Hmong children are not as successful in their education as their peers. Parental involvement in education has consistently been shown to impact academic success and attendance in higher education programs. Little is known about Hmong parental involvement in their children’s education process. Therefore, this study was done to compare and contrast the general family characteristics, parenting methods, parental involvement philosophies, parental involvement experiences, and parental education expectations in Hmong families of high school seniors classified as either high academic achievers or low achievers. Students were classified into either higher or lower academic achievement groups based on their high school cumulative GPA. Five students were randomly selected for each group and a qualitative research interview method was used to interview the students and both of their parents (n=30. The findings showed the parents of the higher academic achieving students were younger, had higher levels of education, and had better relationships and trust with the students. Parents from both groups did not have any written rules for their children to follow at home, they mainly became involved in their children’s education during the elementary and middle school years, and they did not have any specific preference of an educational level, career, or school for their children after high school. Recommendations for ways Hmong families can be encouraged to participate more in education are made.

  16. Achieving High Performance Distributed System: Using Grid, Cluster and Cloud Computing

    Directory of Open Access Journals (Sweden)

    Sunil Kr Singh

    2015-02-01

    Full Text Available To increase the efficiency of any task, we require a system that would provide high performance along with flexibilities and cost efficiencies for user. Distributed computing, as we are all aware, has become very popular over the past decade. Distributed computing has three major types, namely, cluster, grid and cloud. In order to develop a high performance distributed system, we need to utilize all the above mentioned three types of computing. In this paper, we shall first have an introduction of all the three types of distributed computing. Subsequently examining them we shall explore trends in computing and green sustainable computing to enhance the performance of a distributed system. Finally presenting the future scope, we conclude the paper suggesting a path to achieve a Green high performance distributed system using cluster, grid and cloud computing

  17. Diurnal Leaf Starch Content: An Orphan Trait in Forage Legumes

    Directory of Open Access Journals (Sweden)

    Michael E. Ruckle

    2017-02-01

    Full Text Available Forage legumes have a relatively high biomass yield and crude protein content, but their grazed and harvested biomass lacks the high-energy carbohydrates required to meet the productivity potential of modern livestock breeds. Because of their low carbohydrate content, forage legume diets are typically supplemented with starch rich cereal grains or maize (Zea mays, leading to the disruption of local nutrient cycles. Although plant leaves were first reported to accumulate starch in a diurnal pattern over a century ago, leaf starch content has yet to be exploited as an agronomic trait in forage crops. Forage legumes such as red clover (Trifolium pratense have the genetic potential to accumulate up to one third of their leaf dry mass as starch, but this starch is typically degraded at night to support nighttime growth and respiration. Even when diurnal accumulation is considered with regard to the time the crop is harvested, only limited gains are realized due to environmental effects and post-harvest losses from respiration. Here we present original data for starch metabolism in red clover and place it in the broader context of other forage legumes such as, white clover (T. repens, and alfalfa (Medicago sativa. We review the application of recent advances in molecular breeding, plant biology, and crop phenotyping, to forage legumes to improve and exploit a potentially valuable trait for sustainable ruminant livestock production.

  18. Number Sense-Based Strategies Used by High-Achieving Sixth Grade Students Who Experienced Reform Textbooks

    Science.gov (United States)

    Alsawaie, Othman N.

    2012-01-01

    The purpose of this study was to explore strategies used by high-achieving 6th grade students in the United Arab Emirates (UAE) to solve basic arithmetic problems involving number sense. The sample for the study consisted of 15 high-achieving boys and 15 high-achieving girls in grade 6 from 2 schools in the Emirate of Abu Dhabi, UAE. Data for the…

  19. Subpixel shift with Fourier transform to achieve efficient and high-quality image interpolation

    Science.gov (United States)

    Chen, Qin-Sheng; Weinhous, Martin S.

    1999-05-01

    A new approach to image interpolation is proposed. Different from the conventional scheme, the interpolation of a digital image is achieved with a sub-unity coordinate shift technique. In the approach, the original image is first shifted by sub-unity distances matching the locations where the image values need to be restored. The original and the shifted images are then interspersed together, yielding an interpolated image. High quality sub-unity image shift which is crucial to the approach is accomplished by implementing the shift theorem of Fourier transformation. It is well known that under the Nyquist sampling criterion, the most accurate image interpolation can be achieved with the interpolating function (sinc function). A major drawback is its computation efficiency. The present approach can achieve an interpolation quality as good as that with the sinc function since the sub-unity shift in Fourier domain is equivalent to shifting the sinc function in spatial domain, while the efficiency, thanks to the fast Fourier transform, is very much improved. In comparison to the conventional interpolation techniques such as linear or cubic B-spline interpolation, the interpolation accuracy is significantly enhanced. In order to compensate for the under-sampling effects in the interpolation of 3D medical images owing to a larger inter-slice distance, proper window functions were recommended. The application of the approach to 2- and 3-D CT and MRI images produced satisfactory interpolation results.

  20. Achieving high bit rate logical stochastic resonance in a bistable system by adjusting parameters

    Science.gov (United States)

    Yang, Ding-Xin; Gu, Feng-Shou; Feng, Guo-Jin; Yang, Yong-Min; Ball, Andrew

    2015-11-01

    The phenomenon of logical stochastic resonance (LSR) in a nonlinear bistable system is demonstrated by numerical simulations and experiments. However, the bit rates of the logical signals are relatively low and not suitable for practical applications. First, we examine the responses of the bistable system with fixed parameters to different bit rate logic input signals, showing that an arbitrary high bit rate LSR in a bistable system cannot be achieved. Then, a normalized transform of the LSR bistable system is introduced through a kind of variable substitution. Based on the transform, it is found that LSR for arbitrary high bit rate logic signals in a bistable system can be achieved by adjusting the parameters of the system, setting bias value and amplifying the amplitudes of logic input signals and noise properly. Finally, the desired OR and AND logic outputs to high bit rate logic inputs in a bistable system are obtained by numerical simulations. The study might provide higher feasibility of LSR in practical engineering applications. Project supported by the National Natural Science Foundation of China (Grant No. 51379526).

  1. Challenges to achievement of metal sustainability in our high-tech society.

    Science.gov (United States)

    Izatt, Reed M; Izatt, Steven R; Bruening, Ronald L; Izatt, Neil E; Moyer, Bruce A

    2014-04-21

    Achievement of sustainability in metal life cycles from mining of virgin ore to consumer and industrial devices to end-of-life products requires greatly increased recycling rates and improved processing of metals using conventional and green chemistry technologies. Electronic and other high-tech products containing precious, toxic, and specialty metals usually have short lifetimes and low recycling rates. Products containing these metals generally are incinerated, discarded as waste in landfills, or dismantled in informal recycling using crude and environmentally irresponsible procedures. Low recycling rates of metals coupled with increasing demand for high-tech products containing them necessitate increased mining with attendant environmental, health, energy, water, and carbon-footprint consequences. In this tutorial review, challenges to achieving metal sustainability, including projected use of urban mining, in present high-tech society are presented; health, environmental, and economic incentives for various government, industry, and public stakeholders to improve metal sustainability are discussed; a case for technical improvements, including use of molecular recognition, in selective metal separation technology, especially for metal recovery from dilute feed stocks is given; and global consequences of continuing on the present path are examined.

  2. The C-2000 program : achieving high performance through better technologies and changes in the design process

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-09-01

    In 1993, CANMET Energy Technology Centre of Natural Resources Canada launched a demonstration program for high-performance buildings. The focus of the C-2000 Program for Advanced Commercial Buildings was on energy and environmental performance, but it also included a variety of other parameters. Of the 13 buildings that have been designed, some have been built while others are approaching the construction phase. The Canadian Model National Energy Code for Buildings (MNECB) is the standard used as a performance benchmark. The demonstration program has shown that the likelihood of high performance depends on close teamwork by all members of a building design team with the augmentation of a normal design team with an energy engineer, an environmental specialist and a cost consultant. Other factors which help achiever high performance are the use of clear and comprehensive technical guidelines and the development of short written performance strategies. The commissioning of all major systems during the construction phase also help ensure that the systems are properly installed and perform to design levels. The completed projects have confirmed that a 35 to 50 per cent improvement in energy performance levels can be achieved with only modest increases in design budgets. 7 refs., 7 figs.

  3. Achieving high bit rate logical stochastic resonance in a bistable system by adjusting parameters

    Institute of Scientific and Technical Information of China (English)

    杨定新; 谷丰收; 冯国金; 杨拥民

    2015-01-01

    The phenomenon of logical stochastic resonance (LSR) in a nonlinear bistable system is demonstrated by numerical simulations and experiments. However, the bit rates of the logical signals are relatively low and not suitable for practical applications. First, we examine the responses of the bistable system with fixed parameters to different bit rate logic input signals, showing that an arbitrary high bit rate LSR in a bistable system cannot be achieved. Then, a normalized transform of the LSR bistable system is introduced through a kind of variable substitution. Based on the transform, it is found that LSR for arbitrary high bit rate logic signals in a bistable system can be achieved by adjusting the parameters of the system, setting bias value and amplifying the amplitudes of logic input signals and noise properly. Finally, the desired OR and AND logic outputs to high bit rate logic inputs in a bistable system are obtained by numerical simulations. The study might provide higher feasibility of LSR in practical engineering applications.

  4. Achieving High Performance in AC-Field Driven Organic Light Sources.

    Science.gov (United States)

    Xu, Junwei; Carroll, David L; Smith, Gregory M; Dun, Chaochao; Cui, Yue

    2016-04-11

    Charge balance in organic light emitting structures is essential to simultaneously achieving high brightness and high efficiency. In DC-driven organic light emitting devices (OLEDs), this is relatively straight forward. However, in the newly emerging, capacitive, field-activated AC-driven organic devices, charge balance can be a challenge. In this work we introduce the concept of gating the compensation charge in AC-driven organic devices and demonstrate that this can result in exceptional increases in device performance. To do this we replace the insulator layer in a typical field-activated organic light emitting device with a nanostructured, wide band gap semiconductor layer. This layer acts as a gate between the emitter layer and the voltage contact. Time resolved device characterization shows that, at high-frequencies (over 40 kHz), the semiconductor layer allows for charge accumulation in the forward bias, light generating part of the AC cycle and charge compensation in the negative, quiescent part of the AC cycle. Such gated AC organic devices can achieve a non-output coupled luminance of 25,900 cd/m(2) with power efficiencies that exceed both the insulator-based AC devices and OLEDs using the same emitters. This work clearly demonstrates that by realizing balanced management of charge, AC-driven organic light emitting devices may well be able to rival today's OLEDs in performance.

  5. Salt preferences of honey bee water foragers.

    Science.gov (United States)

    Lau, Pierre W; Nieh, James C

    2016-03-01

    The importance of dietary salt may explain why bees are often observed collecting brackish water, a habit that may expose them to harmful xenobiotics. However, the individual salt preferences of water-collecting bees were not known. We measured the proboscis extension reflex (PER) response of Apis mellifera water foragers to 0-10% w/w solutions of Na, Mg and K, ions that provide essential nutrients. We also tested phosphate, which can deter foraging. Bees exhibited significant preferences, with the most PER responses for 1.5-3% Na and 1.5% Mg. However, K and phosphate were largely aversive and elicited PER responses only for the lowest concentrations, suggesting a way to deter bees from visiting contaminated water. We then analyzed the salt content of water sources that bees collected in urban and semi-urban environments. Bees collected water with a wide range of salt concentrations, but most collected water sources had relatively low salt concentrations, with the exception of seawater and swimming pools, which had >0.6% Na. The high levels of PER responsiveness elicited by 1.5-3% Na may explain why bees are willing to collect such salty water. Interestingly, bees exhibited high individual variation in salt preferences: individual identity accounted for 32% of variation in PER responses. Salt specialization may therefore occur in water foragers.

  6. Cognitive abilities and motivational processes in high school students' science achievement and engagement

    Science.gov (United States)

    Lau, Shun

    The dissertation presents two analytic approaches, a variable-centered and person-centered approach, to investigating holistic patterns of the cognitive, motivational, and affective correlates of science achievement and engagement in a sample of 491 10th and 11th grade high-school students. Building on Snow's (1989) idea of two pathways to achievement outcomes, Study 1 adopted a variable-centered approach to examining how cognitive and motivational factors associated with the performance and commitment pathways, respectively, contributed to the prediction of achievement outcomes in science. Results of hierarchical regression analyses showed that (a) students' cognitive abilities were the strongest predictors of their performance in science as measured by standardized test scores; (b) motivational processes enhanced the predictive validity for science test scores and grades beyond the variance accounted for by ability and demography; (c) motivational processes were the strongest predictors of students' commitment to science in the form of situational engagement and anticipated choices of science-related college majors and careers; and (d) competence beliefs served as a point of contact between the performance and commitment pathways. These results are consistent with Snow's (1989) conjecture that both performance and commitment pathway-related factors are necessary for understanding the full range of person-level inputs to achievement outcomes. Study 2 adopted a person-centered approach to examining holistic organizations of psychological factors within individuals and their relations to science achievement and engagement. Four types of students characterized by unique configurations of cognitive, motivational, and affective attributes were identified in both the male and female subsamples using inverse factor analysis. Type membership was found to distinguish students in various indicators of science achievement and engagement. Two of the four types were also found

  7. Race and Academic Achievement in Racially Diverse High Schools: Opportunity and Stratification.

    Science.gov (United States)

    Muller, Chandra; Riegle-Crumb, Catherine; Schiller, Kathryn S; Wilkinson, Lindsey; Frank, Kenneth A

    2010-04-01

    BACKGROUND/CONTEXT: Brown v Board of Education fundamentally changed our nation's schools, yet we know surprisingly little about how and whether they provide equality of educational opportunity. Although substantial evidence suggests that African American and Latino students who attend these schools face fewer learning opportunities than their White counterparts, until now, it has been impossible to examine this using a representative sample because of lack of data. PURPOSE/OBJECTIVE/RESEARCH QUESTION/FOCUS OF STUDY: This study uses newly available data to investigate whether racially diverse high schools offer equality of educational opportunity to students from different racial and ethnic groups. This is examined by measuring the relative representation of minority students in advanced math classes at the beginning of high school and estimating whether and how this opportunity structure limits the level of achievement attained by African American and Latino students by the end of high school. SETTING: This study uses data from the Adolescent Health and Academic Achievement Study (AHAA) and its partner study, the National Longitudinal Study of Adolescent Health (Add Health), a stratified, nationally representative study of students in U.S. high schools first surveyed in 1994-1995. POPULATION/PARTICIPANTS/SUBJECTS: Two samples of racially diverse high schools were used in the analysis: one with African Americans, Whites, and Asians (26 schools with 3,149 students), and the other with Latinos, Whites, and Asians (22 schools with 2,775 students). RESEARCH DESIGN: Quantitative analyses first assess how high schools vary in the extent to which minority students are underrepresented in advanced sophomore math classes. Hierarchical multilevel modeling is then used to estimate whether racial-ethnic differences in representation in advanced math have an impact on African American and Latino students' achievement by the end of high school, relative to the Whites and Asians

  8. HIGH SCHOOL STUDENTS' COGNITIVE FLEXIBILITY IS PREDICTED BY SELF-EFFICACY AND ACHIEVEMENT

    OpenAIRE

    Binnaz Kiran Esen; H. Duygu Özcan; Mehtap Sezgin

    2017-01-01

    In this research, the prediction cognitive flexibility obtained by general self-efficacy, academic self-efficacy, social self-efficacy, emotional self-efficacy and achievement is examined. This study is executed in 2014- 2015 academic year on 760 high school students who are between ages 15 and 18. Cognitive flexibility Scale is developed by Bilgin (2009b) is used for defining cognitive flexibility, Self-Efficacy Scale is developed by Çelikkaleli, Gündoğdu ve Kıran-Esen (2006) is used for def...

  9. Achieving high mass-throughput of therapeutic proteins through parvovirus retentive filters.

    Science.gov (United States)

    Bolton, Glen R; Basha, Jonida; Lacasse, Daniel P

    2010-01-01

    Parvovirus retentive filters that assure removal of viruses and virus-like particles during the production of therapeutic proteins significantly contribute to total manufacturing costs. Operational approaches that can increase throughput and reduce filtration area would result in a significant cost savings. A combination of methods was used to achieve high throughputs of an antibody or therapeutic protein solution through three parvovirus retentive filters. These methods included evaluation of diatomaceous earth or size-based prefilters, the addition of additives, and the optimization of protein concentration, temperature, buffer composition, and solution pH. An optimum temperature of 35°C was found for maximizing throughput through the Virosart CPV and Viresolve Pro filters. Mass-throughput values of 7.3, 26.4, and 76.2 kg/m(2) were achieved through the Asahi Planova 20N, Virosart CPV, and Viresolve Pro filters, respectively, in 4 h of processing. Mass-throughput values of 73, 137, and 192 kg/m(2) were achieved through a Millipore Viresolve Pro filter in 4.0, 8.8, and 22.1 h of processing, respectively, during a single experiment. However, large-scale parvovirus filtration operations are typically controlled to limit volumetric throughput to below the level achieved during small-scale virus spiking experiments. The virus spike may cause significant filter plugging, limiting throughput. Therefore newer parvovirus filter spiking strategies should be adopted that may lead to more representative viral clearance data and higher utilization of large-scale filter capacity. Copyright © 2010 American Institute of Chemical Engineers (AIChE).

  10. Strategies for achieving a high response rate in a home interview survey

    Directory of Open Access Journals (Sweden)

    Power Kevin

    2009-06-01

    Full Text Available Abstract Background Response rates in surveys have been falling over the last 20 years, leading to the need for novel approaches to enhance recruitment. This study describes strategies used to maximise recruitment to a home interview survey of mothers with young children living in areas of high deprivation. Methods Mothers of two year old children received a letter from their GP inviting them to take part in a survey on diet. Participants were subsequently recruited by a researcher. The researcher first tried to contact potential participants by telephone, to discuss the study and make an appointment to conduct a home interview. Where telephone numbers for women could not be obtained from GP records, web searches of publicly available databases were conducted. After obtaining correct telephone numbers, up to six attempts were made to establish contact by telephone. If this was unsuccessful, a postal request for telephone contact was made. Where no telephone contact was achieved, the researcher sent up to two appointments by post to conduct a home interview. Results Participating GPs invited 372 women to take part in a home based interview study. GP practices provided telephone numbers for 162 women, of which 134 were valid numbers. The researcher identified a further 187 numbers from electronic directories. Further searches of GP records by practice staff yielded another 38 telephone numbers. Thus, telephone numbers were obtained for 99% of potential participants. The recruitment rate from telephone contacts was 77%. Most of the gain was achieved within four calls. For the remaining women, contact by post and home visits resulted in 18 further interviews, corresponding to 35% of the women not recruited by telephone. The final interview rate was 82%. This was possible because personal contact was established with 95% of potential participants. Conclusion This study achieved a high response rate in a hard to reach group. This was mainly achieved

  11. High Titer and Yields Achieved with Novel, Low-Severity Pretreatment Strategy

    Energy Technology Data Exchange (ETDEWEB)

    2016-03-01

    NREL researchers obtained high concentration sugar syrups in enzymatic hydrolysis that are fermentable to ethanol and other advanced biofuels and intermediate products at high yields. The novel DMR process is simpler and bypasses all severe pretreatment methods, thus reducing the environmental impact. The results are unprecedented. Researchers achieved a high concentration of sugars (230g/L of monomeric sugar and 270 g/L total sugar) and this low toxicity, highly fermentable syrup yielded 86 g/L ethanol (> 90 percent conversion). In addition, the lignin streams from this process can readily be converted to jet or renewable diesel blendstocks through a hydrodeoxygenation step. The NREL-developed, low severity DMR process may potentially replace higher severity chemical pretreatments and associated expensive reactors constructed of exotic alloys with a simpler process, using commercial-scale equipment commonly associated with the pulp and paper industry, to produce high concentration, low toxicity sugar streams and highly reactive lignin streams from non-food renewable biomass for biological and catalytic upgrading to advanced biofuels and chemicals. The simpler DMR process with black liquor recycling could reduce environmental and life-cycle impacts, and repurpose shuttered pulp and paper mills to help revitalize rural economies.

  12. Oxidative phenols in forage crops containing polyphenol oxidase enzymes.

    Science.gov (United States)

    Parveen, Ifat; Threadgill, Michael D; Moorby, Jon M; Winters, Ana

    2010-02-10

    Polyphenol oxidases (PPOs) are copper-containing enzymes that catalyze oxidation of endogenous monophenols to ortho-dihydroxyaryl compounds and of ortho-dihydroxyaryl compounds to ortho-quinones. Subsequent nucleophilic addition reactions of phenols, amino acids, and proteins with the electrophilic ortho-quinones form brown-, black-, or red-colored secondary products associated with the undesired discolouration of fruit and vegetables. Several important forage plants also exhibit significant PPO activity, and a link with improved efficiency of ruminant production has been established. In ruminant animals, extensive degradation of forage proteins, following consumption, can result in high rates of excretion of nitrogen, which contributes to point-source and diffuse pollution. Reaction of quinones with forage proteins leads to the formation of protein-phenol complexes that are resistant to proteolytic activity during ensilage and during rumen fermentation. Thus, PPO in red clover (Trifolium pratense) has been shown to improve protein utilization by ruminants. While PPO activity has been demonstrated in a number of forage crops, little work has been carried out to identify substrates of PPO, knowledge of which would be beneficial for characterizing this trait in these forages. In general, a wide range of 1,2-dihydroxyarenes can serve as PPO substrates because these are readily oxidized because of the ortho positioning of the hydroxy groups. Naturally occurring phenols isolated from forage crops with PPO activity are reviewed. A large number of phenols, which may be directly or indirectly oxidized as a consequence of PPO activity, have been identified in several forage grass, legume, cereal, and brassica species; these include hydroxybenzoic acids, hydroxycinnamates, and flavonoids. In conclusion, a number of compounds are known or postulated to enable PPO activity in important PPO-expressing forage crops. Targeting the matching of these compounds with PPO activity

  13. Achieving high mobility ZnO : Al at very high growth rates by dc filtered cathodic arc deposition

    Energy Technology Data Exchange (ETDEWEB)

    Mendelsberg, R J; Lim, S H N; Wallig, J; Anders, A [Lawrence Berkeley National Laboratory, Plasma Applications Group, Berkeley, CA (United States); Zhu, Y K [Harbin Institute of Technology, Harbin (China); Milliron, D J, E-mail: aanders@lbl.gov [Lawrence Berkeley National Laboratory, Molecular Foundry, Berkeley, CA (United States)

    2011-06-15

    Achieving a high growth rate is paramount for making large-area transparent conducting oxide coatings at a low cost. Unfortunately, the quality of thin films grown by most techniques degrades as the growth rate increases. Filtered dc cathodic arc is a lesser known technique which produces a stream of highly ionized plasma, in stark contrast to the neutral atoms produced by standard sputter sources. Ions bring a large amount of potential energy to the growing surface which is in the form of heat, not momentum. By minimizing the distance from cathode to substrate, the high ion flux gives a very high effective growth temperature near the film surface without causing damage from bombardment. The high surface temperature is a direct consequence of the high growth rate and allows for high-quality crystal growth. Using this technique, 500-1300 nm thick and highly transparent ZnO : Al films were grown on glass at rates exceeding 250 nm min{sup -1} while maintaining resistivity below 5 x 10{sup -4} {Omega} cm with electron mobility as high as 60 cm{sup 2} V{sup -1} s{sup -1}. (fast track communication)

  14. A Novel Dual-Electrode Plug to Achieve Intensive Electric Field for High Performance Ignition

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2013-01-01

    Full Text Available A thorough analysis of electric field is carried out so as to verify that a novel dual-electrode plug can build intensive electric field and can improve the main drawbacks of feeble electric field and low ignition efficiency of the traditional plug. With intensive electric field, the proposed novel plug can achieve high performance ignition, resulting in fuel saving and exhaust reduction. Gauss law is applied for electric field analysis to show that intensive electric field can be built by the novel plug. Then, according to Faraday law a lower-voltage ignition feature accomplished by the plug is discussed. Compared with traditional plug, the novel dual-electrode plug has the following advantages. (1 Much higher energy density is built between the plug electrodes, lowering ignition voltage requirement. (2 Electromagnetic interference (EMI problem caused by high ignition voltage is readily resolved. (3 Ignition time delay can be improved. (4 The feature to save fuel consuming is achieved. (5 The exhaust of CO and HC is reduced significantly. Practical measurements are fulfilled to validate the electric field analysis and to demonstrate the features of the proposed dual-electrode plug.

  15. Forage based animal production systems and sustainability, an invited keynote

    Directory of Open Access Journals (Sweden)

    Abdul Shakoor Chaudhry

    2008-07-01

    Full Text Available Forages are essential for the successful operation of animal production systems. This is more relevant to ruminants which are heavily dependant upon forages for their health and production in a cost-effective and sustainable manner. While forages are an economical source of nutrients for animal production, they also help conserve the soil integrity, water supply and air quality. Although the role of these forages for animal production could vary depending upon the regional preferences for the animal and forage species, climate and resources, their importance in the success of ruminant production is acknowledged. However with the increasing global human population and urbanisation, the sustainability of forage based animal production systems is sometimes questioned due to the interrelationship between animal production and the environment. It is therefore vital to examine the suitability of these systems for their place in the future to supply quality food which is safe for human consumption and available at a competitive price to the growing human population. Grassland and forage crops are recognised for their contribution to the environment, recreation and efficiency of meat and milk production,. To maintain sustainability, it is crucial that such farming systems remain profitable and environmentally friendly while producing nutritious foods of high economical value. Thus, it is pertinent to improve the nutritive value of grasses and other forage plants in order to enhance animal production to obtain quality food. It is also vital to develop new forages which are efficiently utilised and wasted less by involving efficient animals. A combination of forage legumes, fresh or conserved grasses, crop residues and other feeds could help develop an animal production system which is economically efficient, beneficial and viable. Also, it is crucial to use efficient animals, improved forage conservation methods, better manure handling, and minimum

  16. The ecological economics of kleptoparasitism: pay-offs from self-foraging versus kleptoparasitism.

    Science.gov (United States)

    Flower, Tom P; Child, Matthew F; Ridley, Amanda R

    2013-01-01

    Animals commonly steal food from other species, termed interspecific kleptoparasitism, but why animals engage in kleptoparasitism compared with alternate foraging tactics, and under what circumstances they do so, is not fully understood. Determining what specific benefits animals gain from kleptoparasitism could provide valuable insight into its evolution. Here, we investigate the benefits of kleptoparasitism for a population of individually recognizable and free-living fork-tailed drongos (Dicrurus adsimilis) in the southern Kalahari Desert. Drongos engaged in two foraging behaviours: self-foraging for small insects or following other species which they kleptoparasitized for larger terrestrial prey that they could not capture themselves. Kleptoparasitism consequently enabled drongos to exploit a new foraging niche. Kleptoparasitism benefitted drongos most in the morning and on colder days because at these times pay-offs from kleptoparasitism remained stable, while those from self-foraging declined. However, drongos engaged in kleptoparasitism less than expected given the overall high (but more variable) pay-offs from this behaviour, suggesting that kleptoparasitism is a risky foraging tactic and may incur additional foraging costs compared with self-foraging. This is the first study to comprehensively investigate the benefits of facultatively engaging in kleptoparasitism, demonstrating that animals may switch to kleptoparasitism to exploit a new foraging niche when pay-offs exceed those from alternate foraging behaviours.

  17. What Makes a Good Program? A Case Study of a School Admitting High Academic Achievers

    Directory of Open Access Journals (Sweden)

    Ching Man Lam

    2008-01-01

    Full Text Available This paper reports the results of a qualitative study that explored the administration and implementation of the Tier 1 Program (Secondary 1 Curriculum of the Project P.A.T.H.S. The case study method was used to explore perceptions of the teachers and the project coordinator of program effectiveness, and to identify various factors for program success. A school admitting high academic achievers was selected, and site visits, as well as individual and focus group interviews, were conducted with the program coordinator, social worker, and course teachers. The results suggested that clear vision and program goals, high quality of curriculum, helpful leadership, positive teacher attitude, and strong administrative support are factors for program success. Analyzing the data enables the researchers to understand the characteristics of a successful program as well as the interplay among factors for producing success.

  18. Evidence for ship noise impacts on humpback whale foraging behaviour.

    Science.gov (United States)

    Blair, Hannah B; Merchant, Nathan D; Friedlaender, Ari S; Wiley, David N; Parks, Susan E

    2016-08-01

    Noise from shipping activity in North Atlantic coastal waters has been steadily increasing and is an area of growing conservation concern, as it has the potential to disrupt the behaviour of marine organisms. This study examines the impacts of ship noise on bottom foraging humpback whales (Megaptera novaeangliae) in the western North Atlantic. Data were collected from 10 foraging whales using non-invasive archival tags that simultaneously recorded underwater movements and the acoustic environment at the whale. Using mixed models, we assess the effects of ship noise on seven parameters of their feeding behaviours. Independent variables included the presence or absence of ship noise and the received level of ship noise at the whale. We found significant effects on foraging, including slower descent rates and fewer side-roll feeding events per dive with increasing ship noise. During 5 of 18 ship passages, dives without side-rolls were observed. These findings indicate that humpback whales on Stellwagen Bank, an area with chronically elevated levels of shipping traffic, significantly change foraging activity when exposed to high levels of ship noise. This measureable reduction in within-dive foraging effort of individual whales could potentially lead to population-level impacts of shipping noise on baleen whale foraging success.

  19. Nutritional Characteristics of Forage Grown in South of Benin

    Directory of Open Access Journals (Sweden)

    Nadia Musco

    2016-01-01

    Full Text Available In order to provide recommendations on the most useful forage species to smallholder farmers, eleven grass and eleven legume forages grown in Abomey-Calavi in Republic of Benin were investigated for nutritive value (i.e. chemical composition and energy content and fermentation characteristics (i.e. gas and volatile fatty acid production, organic matter degradability. The in vitro gas production technique was used, incubating the forages for 120 h under anaerobic condition with buffalo rumen fluid. Compared to legume, tropical grass forages showed lower energy (8.07 vs 10.57 MJ/kg dry matter [DM] and crude protein level (16.10% vs 19.91% DM and higher cell wall content (neutral detergent fiber: 63.8% vs 40.45% DM, respectively. In grass forages, the chemical composition showed a quite high crude protein content; the in vitro degradability was slightly lower than the range of tropical pasture. The woody legumes were richer in protein and energy and lower in structural carbohydrates than herbaceous plants, however, their in vitro results are influenced by the presence of complex compounds (i.e. tannins. Significant correlations were found between chemical composition and in vitro fermentation characteristics. The in vitro gas production method appears to be a suitable technique for the evaluation of the nutritive value of forages in developing countries.

  20. Does greed help a forager survive?

    Science.gov (United States)

    Bhat, U.; Redner, S.; Bénichou, O.

    2017-06-01

    We investigate the role of greed on the lifetime of a random-walking forager on an initially resource-rich lattice. Whenever the forager lands on a food-containing site, all the food there is eaten and the forager can hop S more steps without food before starving. Upon reaching an empty site, the forager comes one time unit closer to starvation. The forager is also greedy—given a choice to move to an empty or to a food-containing site in its local neighborhood, the forager moves preferentially toward food. Surprisingly, the forager lifetime varies nonmonotonically with greed, with different senses of the nonmonotonicity in one and two dimensions. Also unexpectedly, the forager lifetime in one dimension has a huge peak for very negative greed where the forager is food averse.

  1. BIOACCUMULATION OF HEAVY METALS IN FORAGE GRASSES

    Directory of Open Access Journals (Sweden)

    Adam Łukowski

    2017-02-01

    Full Text Available The aim of this study was estimation of bioaccumulation of heavy metals (Pb, Ni, Cu, Zn, Cd in forage grasses from the area of Podlasie Province based on the bioaccumulation factor. In the soil samples the pH, organic carbon content and CEC were determined. Determination of heavy metals contents in plant and soil material was carried out by flame atomic absorption spectrometry. Soils were characterized mainly by acidic reaction, high cation exchange capacity and organic carbon content. The content of heavy metals in studied forage grasses did not exceed the polish regulations related to plant usage for feeding purposes, except the lead content in seven samples. Coefficients of variation for particular heavy metals content in studied forage grasses were as follows: Pb - 37%, Ni - 63%, Cu - 30%, Zn - 34%, Cd - 48%. The highest bioaccumulation factor was found for nickel and grass from the village Remieńkiń (11.54, while the lowest for cadmium and grass from the village Jemieliste (0.04.

  2. Effects of forage type, forage to concentrate ratio, and crushed linseed supplementation on milk fatty acid profile in lactating dairy cows

    NARCIS (Netherlands)

    Sterk, A.R.; Johansson, B.E.O.; Taweel, H.Z.H.; Murphy, M.; Vuuren, van A.M.; Hendriks, W.H.; Dijkstra, J.

    2011-01-01

    The effects of an increasing proportion of crushed linseed (CL) in combination with varying forage type (grass or corn silage) and forage to concentrate ratio (F:C), and their interactions on milk fatty acid (FA) profile of high-producing dairy cows was studied using a 3-factor Box-Behnken design. S

  3. Is Early Ability Grouping Good for High-Achieving Students' Psychosocial Development? Effects of the Transition into Academically Selective Schools

    Science.gov (United States)

    Becker, Michael; Neumann, Marko; Tetzner, Julia; Böse, Susanne; Knoppick, Henrike; Maaz, Kai; Baumert, Jürgen; Lehmann, Rainer

    2014-01-01

    The present study investigates school context effects on psychosocial characteristics (academic self-concept, peer relations, school satisfaction, and school anxiety) of high-achieving and gifted students. Students who did or did not make an early transition from elementary to secondary schools for high-achieving and gifted students in 5th grade…

  4. A Comparison of Strategic Development for Multiplication Problem Solving in Low-, Average-, and High-Achieving Students

    Science.gov (United States)

    Zhang, Dake; Ding, Yi; Barrett, Dave E.; Xin, Yan Ping; Liu, Ru-de

    2014-01-01

    The present study investigated the differences of strategy use between low-, average-, and high-achieving students when solving different multiplication problems. Nineteen high-, 48 average-, and 17 low-achieving students participated in this study. All participants were asked to complete three different multiplication tests and to explain how…

  5. High and Low Reading Comprehension Achievers' Strategic Behaviors and Their Relation to Performance in a Reading Comprehension Situation

    Science.gov (United States)

    Dermitzaki, Irini; Andreou, Georgia; Paraskeva, Violetta

    2008-01-01

    This study aimed at investigating the actual strategic behaviors of high and low achievers in reading comprehension and their relation with respective performance. The participants were 45 individually examined third graders, 20 high and 25 low reading comprehension achievers. Cognitive, metacognitive, and motivational aspects of the participants'…

  6. Development of a 14-inch ID High-Pressure Hybrid Riser for SBOP Drilling Développement d’un riser hybride 14”ID haute pression pour le forage SBOP

    Directory of Open Access Journals (Sweden)

    Persent E.

    2009-11-01

    Full Text Available This paper discusses the development of a 14-inch ID high-pressure hybrid riser (10 000 psi for surface BOP drilling in ultra-deep water (10 000 ft. The high-pressure hybrid riser system is obtained by adapting and combining two existing technologies, previously developed by the IFP for other applications: – the Clip connector, a double breech-block type connector to provide a quick and safe connection for riser joints; – hybrid pipe technology, a steel pipe hoop-wound with tapes of carbon fibers impregnated with polyamide thermoplastic resin. IFP has developed a new 14-inch ID HP Clip connector for the hybrid riser application. The connector is capable of withstanding a 2.8 million pound tension and a 10 000 psi operating pressure. In addition, a 16-inch nominal OD hybrid riser pipe has been designed to replace the steel riser pipe with a thinnerwalled hoop-wound steel pipe. The significant weight savings that can be achieved with the hybrid riser pipe make it possible to design an effective riser architecture to withstand the high pressure and deep water requirements. Pursuant to design studies, a 14-inch ID prototype assembly consisting of two hybrid riser pipe sections with a high-pressure Clip connector was manufactured. A test program, including burst and collapse tests as well as cyclic fatigue testing, was formulated and carried out to qualify the performance of the Clip connector and hybrid riser pipe system. Completion of hybrid pipe additional fatigue testing and realization of a scale-one field testing of the hybrid riser are considered as the next steps of the project. To date, the main test results (burst, collapse, fatigue resistance confirm that the Clip connector and the hybrid pipe technologies are well suited for ultra-deep sea drilling with a surface BOP. However, the fatigue resistance of hybrid riser pipes still needs to be better characterized. Cet article présente le développement d’un riser hybride 14”ID haute

  7. Not choosing nursing: work experience and career choice of high academic achieving school leavers.

    Science.gov (United States)

    Neilson, Gavin R; McNally, James G

    2010-01-01

    Work experience has been a feature of the secondary school curriculum in the United Kingdom for a number of years. Usually requested by the pupil, it aims to provide opportunities for school pupils to enhance their knowledge and understanding of an occupation. The main benefits are claimed to be that it can help pupils develop an insight into the skills and attitudes required for an occupation and an awareness of career opportunities. However the quality and choice of placements are considered to be of great importance in this process and in influencing career choice [Department for Education and Skills (DfES), 2002a. Work Experience: A Guide for Employers. Department for Education and Skills, London]. As university departments of nursing experience a decline in the number of school pupils entering student nurse education programmes, and with the competition for school leavers becoming even greater, it is important to consider whether school pupils have access to appropriate work placements in nursing and what influence their experience has on pursuing nursing as a career choice. This paper is based on interview data from 20 high academic achieving fifth and sixth year school pupils in Scotland, paradigmatic cases from a larger survey sample (n=1062), who had considered nursing as a possible career choice within their career preference cluster, but then later disregarded nursing and decided to pursue medicine or another health care profession. This was partly reported by Neilson and Lauder [Neilson, G.R., Lauder, W., 2008. What do high academic achieving school pupils really think about a career in nursing: analysis of the narrative from paradigmatic case interviews. Nurse Education Today 28(6), 680-690] which examined what high academic achieving school pupils really thought about a career in nursing. However, the data was particularly striking in revealing the poor quality of nursing work experience for the pupils, and also their proposal that there was a need

  8. High school students' perceptions of EFL teacher control orientations and their English academic achievement.

    Science.gov (United States)

    Kiany, Gholam Reza; Shayestefar, Parvaneh

    2011-09-01

    BACKGROUND. Theories distinguish between student-initiated and teacher-initiated regulation of students' learning activities, or between strong, shared, or loose teacher control during the completion of learning tasks. Empirical validations for such distinctions are scarce, however. AIM. The present study aimed at (a) investigating students' perceptions of control behaviours exhibited by their English teachers; and (b) exploring the contribution of different types of teacher control behaviours to students' cognitive outcomes (English Achievement). SAMPLE. The sample comprised 732 English as a Foreign Language (EFL) students studying in three major fields of high school (Mathematics, Natural Science, and Humanities). The participants (16-17 years of age) were selected from third-grade classes of 27 EFL teachers working in 25 high schools of 6 main different geographical regions in the Isfahan province, Iran. METHOD. To obtain a comprehensive picture of different control types exhibited by Iranian EFL teachers, the control subscales of the two existing questionnaires, i.e., the Questionnaire on Instructional Behaviours (QIB), adapted by Den Brok et al. (2004) and the Questionnaire on Lesson Activities (QLA) used by Den Brok (2001) were merged to form the Questionnaire of Teacher Control (QTC). The development of this Persian instrument involved several steps: translation and back translation by the researchers, one expert translator, and two EFL teachers; piloting; and a final administration of the questionnaire to the student sample. With respect to the second aim of the study, data regarding students' performances on the Standardized National English Achievement Tests were gathered from local educational offices and schools. RESULTS AND CONCLUSION. Statistical analyses supported acceptable reliability and validity of the instrument. A main factor structure with three types of teacher control (strong/high, shared/mid, and loose/low) was found to underlie students

  9. Theoretical Study of Monolayer and Double-Layer Waveguide Love Wave Sensors for Achieving High Sensitivity.

    Science.gov (United States)

    Li, Shuangming; Wan, Ying; Fan, Chunhai; Su, Yan

    2017-03-22

    Love wave sensors have been widely used for sensing applications. In this work, we introduce the theoretical analysis of the monolayer and double-layer waveguide Love wave sensors. The velocity, particle displacement and energy distribution of Love waves were analyzed. Using the variations of the energy repartition, the sensitivity coefficients of Love wave sensors were calculated. To achieve a higher sensitivity coefficient, a thin gold layer was added as the second waveguide on top of the silicon dioxide (SiO₂) waveguide-based, 36 degree-rotated, Y-cut, X-propagating lithium tantalate (36° YX LiTaO₃) Love wave sensor. The Love wave velocity was significantly reduced by the added gold layer, and the flow of wave energy into the waveguide layer from the substrate was enhanced. By using the double-layer structure, almost a 72-fold enhancement in the sensitivity coefficient was achieved compared to the monolayer structure. Additionally, the thickness of the SiO₂ layer was also reduced with the application of the gold layer, resulting in easier device fabrication. This study allows for the possibility of designing and realizing robust Love wave sensors with high sensitivity and a low limit of detection.

  10. High school students with asthma: attitudes about school health, absenteeism, and its impact on academic achievement.

    Science.gov (United States)

    Krenitsky-Korn, Susan

    2011-01-01

    Asthma is the most frequent reason for absence from school; it accounts for one-third of all days of missed instruction, placing students at risk for academic failure and social isolation. This study compared high school students with asthma with those without asthma, and examined the relationship of their attitudes toward school health services, absenteeism, academic achievement, and the supposition that school nurse services play an essential part in the academic process. Surveys were completed by all students who participated in the study. Twenty-eight students with asthma reported levels of illness and school nurse support in an additional survey. Data revealed that students with asthma were absent more frequently, scored lower in mathematics, and participated less in school activities than their peers without asthma. Their level of illness did not predict the number of days absent, which was negatively correlated with achievement and positively correlated with students' permissive attitudes toward absenteeism. Findings indicate that school nurse interventions were sources of physical, social, emotional, and academic support.

  11. Conflicts and communication between high-achieving Chinese American adolescents and their parents.

    Science.gov (United States)

    Qin, Desiree Baolian; Chang, Tzu-Fen; Han, Eun-Jin; Chee, Grace

    2012-01-01

    Drawing on in-depth interview data collected on 18 high-achieving Chinese American students, the authors examine domains of acculturation-based conflicts, parent and child internal conflicts, and conflict resolution in their families. Their analyses show that well-established negative communication patterns in educational expectations, divergent attitudes toward other races and country of origin, and cultural and language barriers contributed to parent-child conflicts. Their findings also illustrate important internal conflicts both adolescents and parents had along the cultural tightrope of autonomy and relatedness. Finally, the vertical in-group conflict resolution style that was evidenced in youths' accounts raises questions about cultural differences in constructive versus destructive conflict resolution styles. © 2012 Wiley Periodicals, Inc., A Wiley Company.

  12. Identifying Winter Forage Triticale (X Triticosecale Wittmack) Strains for the Central Great Plains

    Science.gov (United States)

    Triticale (X Triticosecale Wittmack), a human-made crop, is mainly used as a forage crop in the central Great Plains. A successful triticale cultivar should have high forage yield with good quality, and also high grain yield so the seed can be economically produced. Hence, the purpose of this study...

  13. Exploring the Self-efficacy Beliefs among the High Achievers in Writing

    Directory of Open Access Journals (Sweden)

    Ilyana Jalaluddin

    2014-01-01

    Full Text Available Learners form their self-efficacy beliefs by interpreting information primarily from four sources namely performance accomplishments, vicarious experiences, verbal persuasion, and emotional arousal. It is important to recognize the four cognitive nature of self-efficacy because the cognitive appraisal of information from the four sources will influence self-efficacy and it cannot be evaluated based on one source per se (Lane, Jones & Stevens 2002. This article explores the four sources of self-efficacy among the high achievers in writing course. In analysing the finding, Z-scores were derived from each self-efficacy component score based on the aggregate mean and the standard deviation of the class. Findings show high frequency of negative z-value reported for Specific Progress (SPR and Social Feedback (SF. Meanwhile, high frequency of positive z-value is found in the General Progress (GPR and Physiological States (PS components. Based on the finding, pedagogical implications, limitations and directions for further research are presented.

  14. Differences in Personality Characteristics between Groups Having High and Low Mathematical Achievement Gain under Individualized Instruction.

    Science.gov (United States)

    Neufeld, K. Allen

    The problem of this study was to determine the relationship of selected characteristics of pupils to achievement gain in elementary school mathematics classes using the Individualized Mathematics Curriculum Project (IMCP) approach. Analysis o f data was based primarily on pre-achievement and post-achievement scores. The hypothesis that there was…

  15. Achieving a high-reliability organization through implementation of the ARCC model for systemwide sustainability of evidence-based practice.

    Science.gov (United States)

    Melnyk, Bernadette Mazurek

    2012-01-01

    High-reliability health care organizations are those that provide care that is safe and one that minimizes errors while achieving exceptional performance in quality and safety. This article presents major concepts and characteristics of a patient safety culture and a high-reliability health care organization and explains how building a culture of evidence-based practice can assist organizations in achieving high reliability. The ARCC (Advancing Research and Clinical practice through close Collaboration) model for systemwide implementation and sustainability of evidence-based practice is highlighted as a key strategy in achieving high reliability in health care organizations.

  16. Opportunities to enhance performance and efficiency through nutrient synchrony in forage-fed ruminants.

    Science.gov (United States)

    Hersom, M J

    2008-04-01

    Increasingly, the need for optimized nutrient utilization to address increasing production costs and environmental considerations will necessitate opportunities to improve nutrient synchrony. Historically, attempts at synchronizing nutrient supply in ruminants, particularly in cattle consuming high-forage diets, have met with variable results. The success of nutrient synchrony has been measured primarily in ruminants by increases in microbial yield, microbial efficiency, nutrient utilization, and to a lesser extent, animal performance. Successful synchrony of nutrient supply to cattle consuming forage-based diets faces several challenges. From a feed supply aspect, the challenges to nutrient synchrony include accurately measuring forage intake and consumed forage chemical composition. The issue of forage intake and chemical composition is perhaps the most daunting for producers grazing cattle. Indeed, for forage-fed cattle, the availability of forage protein and carbohydrate can be the most asynchronous aspect of the diet. In most grazed forages, digestion rates of the carbohydrate fractions are much slower than that of the corresponding protein fractions. Additionally, the forage-supplement interaction exerts a large impact on the synchrony of nutrients. The supplemental feedstuffs compose the component of the nutrient synchrony scenario that is most often manipulated to influence synchrony. The supplement type (e.g., starch vs. fiber, dry vs. liquid), nutrient profile, and degradation rates are often prime considerations associated with nutrient synchrony on high forage diets. Other considerations that warrant attention include temporal intake patterns of the forage and supplement, increased use and types of coproduct supplements, and an assessment of the success of nutrient synchrony. Synchronization of nutrient utilization by forage-fed ruminants has and will continue to encounter challenges for successful outcomes. Ultimately it is the improvement in animal

  17. Achieving High-Energy-High-Power Density in a Flexible Quasi-Solid-State Sodium Ion Capacitor.

    Science.gov (United States)

    Li, Hongsen; Peng, Lele; Zhu, Yue; Zhang, Xiaogang; Yu, Guihua

    2016-09-14

    Simultaneous integration of high-energy output with high-power delivery is a major challenge for electrochemical energy storage systems, limiting dual fine attributes on a device. We introduce a quasi-solid-state sodium ion capacitor (NIC) based on a battery type urchin-like Na2Ti3O7 anode and a capacitor type peanut shell derived carbon cathode, using a sodium ion conducting gel polymer as electrolyte, achieving high-energy-high-power characteristics in solid state. Energy densities can reach 111.2 Wh kg(-1) at power density of 800 W kg(-1), and 33.2 Wh kg(-1) at power density of 11200 W kg(-1), which are among the best reported state-of-the-art NICs. The designed device also exhibits long-term cycling stability over 3000 cycles with capacity retention ∼86%. Furthermore, we demonstrate the assembly of a highly flexible quasi-solid-state NIC and it shows no obvious capacity loss under different bending conditions.

  18. Root Foraging Performance and Life-History Traits.

    Science.gov (United States)

    Weiser, Martin; Koubek, Tomáš; Herben, Tomáš

    2016-01-01

    Plants use their roots to forage for nutrients in heterogeneous soil environments, but different plant species vastly differ in the intensity of foraging they perform. This diversity suggests the existence of constraints on foraging at the species level. We therefore examined the relationships between the intensity of root foraging and plant body traits across species in order to estimate the degree of coordination between plant body traits and root foraging as a form of plant behavior. We cultivated 37 perennial herbaceous Central European species from open terrestrial habitats in pots with three different spatial gradients of nutrient availability (steep, shallow, and no gradient). We assessed the intensity of foraging as differences in root placement inside pots with and without a spatial gradient of resource supply. For the same set of species, we retrieved data about body traits from available databases: maximum height at maturity, mean area of leaf, specific leaf area, shoot lifespan, ability to self-propagate clonally, maximal lateral spread (in clonal plants only), realized vegetative growth in cultivation, and realized seed regeneration in cultivation. Clonal plants and plants with extensive vegetative growth showed considerably weaker foraging than their non-clonal or slow-growing counterparts. There was no phylogenetic signal in the amount of expressed root foraging intensity. Since clonal plants foraged less than non-clonals and foraging intensity did not seem to be correlated with species phylogeny, we hypothesize that clonal growth itself (i.e., the ability to develop at least partly self-sustaining ramets) may be an answer to soil heterogeneity. Whereas unitary plants use roots as organs specialized for both resource acquisition and transport to overcome spatial heterogeneity in resource supply, clonal plants separate these two functions. Becoming a clonal plant allows higher specialization at the organ level, since a typical clonal plant can be

  19. Seasonal variations in the diet and foraging behaviour of dunlins Calidris alpina in a south European estuary: improved feeding conditions for northward migrants.

    Directory of Open Access Journals (Sweden)

    Ricardo C Martins

    Full Text Available During the annual cycle, migratory waders may face strikingly different feeding conditions as they move between breeding areas and wintering grounds. Thus, it is of crucial importance that they rapidly adjust their behaviour and diet to benefit from peaks of prey abundance, in particular during migration, when they need to accumulate energy at a fast pace. In this study, we compared foraging behaviour and diet of wintering and northward migrating dunlins in the Tagus estuary, Portugal, by video-recording foraging birds and analysing their droppings. We also estimated energy intake rates and analysed variations in prey availability, including those that were active at the sediment surface. Wintering and northward migrating dunlins showed clearly different foraging behaviour and diet. In winter, birds predominantly adopted a tactile foraging technique (probing, mainly used to search for small buried bivalves, with some visual surface pecking to collect gastropods and crop bivalve siphons. Contrastingly, in spring dunlins generally used a visual foraging strategy, mostly to consume worms, but also bivalve siphons and shrimps. From winter to spring, we found a marked increase both in the biomass of invertebrate prey in the sediment and in the surface activity of worms and siphons. The combination of these two factors, together with the availability of shrimps in spring, most likely explains the changes in the diet and foraging behaviour of dunlins. Northward migrating birds took advantage from the improved feeding conditions in spring, achieving 65% higher energy intake rates as compared with wintering birds. Building on these results and on known daily activity budgets for this species, our results suggest that Tagus estuary provides high-quality feeding conditions for birds during their stopovers, enabling high fattening rates. These findings show that this large wetland plays a key role as a stopover site for migratory waders within the East

  20. Seasonal variations in the diet and foraging behaviour of dunlins Calidris alpina in a south European estuary: improved feeding conditions for northward migrants.

    Science.gov (United States)

    Martins, Ricardo C; Catry, Teresa; Santos, Carlos D; Palmeirim, Jorge M; Granadeiro, José P

    2013-01-01

    During the annual cycle, migratory waders may face strikingly different feeding conditions as they move between breeding areas and wintering grounds. Thus, it is of crucial importance that they rapidly adjust their behaviour and diet to benefit from peaks of prey abundance, in particular during migration, when they need to accumulate energy at a fast pace. In this study, we compared foraging behaviour and diet of wintering and northward migrating dunlins in the Tagus estuary, Portugal, by video-recording foraging birds and analysing their droppings. We also estimated energy intake rates and analysed variations in prey availability, including those that were active at the sediment surface. Wintering and northward migrating dunlins showed clearly different foraging behaviour and diet. In winter, birds predominantly adopted a tactile foraging technique (probing), mainly used to search for small buried bivalves, with some visual surface pecking to collect gastropods and crop bivalve siphons. Contrastingly, in spring dunlins generally used a visual foraging strategy, mostly to consume worms, but also bivalve siphons and shrimps. From winter to spring, we found a marked increase both in the biomass of invertebrate prey in the sediment and in the surface activity of worms and siphons. The combination of these two factors, together with the availability of shrimps in spring, most likely explains the changes in the diet and foraging behaviour of dunlins. Northward migrating birds took advantage from the improved feeding conditions in spring, achieving 65% higher energy intake rates as compared with wintering birds. Building on these results and on known daily activity budgets for this species, our results suggest that Tagus estuary provides high-quality feeding conditions for birds during their stopovers, enabling high fattening rates. These findings show that this large wetland plays a key role as a stopover site for migratory waders within the East Atlantic Flyway.

  1. Evaluation of dialyzer jacket structure and hollow-fiber dialysis membranes to achieve high dialysis performance.

    Science.gov (United States)

    Hirano, Ayaka; Yamamoto, Ken-ichiro; Matsuda, Masato; Ogawa, Takehito; Yakushiji, Taiji; Miyasaka, Takehiro; Sakai, Kiyotaka

    2011-02-01

    The objective of this study was to determine the optimum dialyzer jacket structure and hollow-fiber dialysis membrane, both of which are indispensable factors for achieving high dialysis performance, by clarifying the relationship between the dialysis performance and the flow of dialysate and blood in a hollow-fiber dialyzer. We evaluated the clearance, dialysate, and blood flow for four commercially available hollow-fiber dialyzers, namely, the APS-15S, APS-15SA, TS-1.6UL, and CX-1.6U. To evaluate dialysate and blood flow, we measured the residence-time distribution of dialysate and blood flow of these dialyzers by the pulse-response method. We also determined the clearances of urea, creatinine, vitamin B(12), and lysozyme to evaluate the dialysis performance of these dialyzers. While the baffle and taper structures allow effective supply of dialysate into the dialyzer jacket, the hollow-fiber shape, inner diameter, and packing density significantly influence the dialysate flow. In dialyzers with long taper-holding slits, the slit area is a key design parameter for achieving optimum dialysate flow. Similarly, the blood flow is significantly influenced by the structure of the inflowing and outflowing blood ports at the header of a dialyzer, and the shape and inner diameter of the hollow fibers. Hollow fibers with smaller inner diameters cause an increase in blood pressure, which causes blood to enter the hollow fibers more easily. The hollow-fiber shape hardly affects the blood flow. While improved dialysate and blood flow cause higher clearance of low molecular-weight substances, higher membrane area and pure-water permeability accelerate internal filtration, thereby causing an increase in the clearance of large molecular-weight substances. © 2010 The Authors. Therapeutic Apheresis and Dialysis © 2010 International Society for Apheresis.

  2. Achieving Energy Savings with Highly-Controlled Lighting in an Open-Plan Office

    Energy Technology Data Exchange (ETDEWEB)

    Rubinstein, Francis; Enscoe, Abby

    2010-04-19

    An installation in a Federal building tested the effectiveness of a highly-controlled, workstation-specific lighting retrofit. The study took place in an open-office area with 86 cubicles and low levels of daylight. Each cubicle was illuminated by a direct/indirectpendant luminaire with three 32 watt lamps, two dimmable DALI ballasts, and an occupancy sensor. A centralized control system programmed all three lamps to turn on and off according to occupancy on a workstation-by-workstation basis. Field measurements taken over the course of several monthsdemonstrated 40% lighting energy savings compared to a baseline without advanced controls that conforms to GSA's current retrofit standard. A photometric analysis found that the installation provided higher desktop light levels than the baseline, while an occupant survey found that occupants in general preferred the lighting system to thebaseline.Simple payback is fairly high; projects that can achieve lower installation costs and/or higher energy savings and those in which greenhouse gas reduction and occupant satisfaction are significant priorities provide the ideal setting for workstation-specific lighting retrofits.

  3. A high-throughput method for the quantification of proanthocyanidins in forage crops and its application in assessing variation in condensed tannin content in breeding programmes for Lotus corniculatus and Lotus uliginosus.

    Science.gov (United States)

    Marshall, Athole; Bryant, David; Latypova, Galina; Hauck, Barbara; Olyott, Phil; Morris, Phillip; Robbins, Mark

    2008-02-13

    Lotus corniculatus and Lotus uliginosus are agronomically important forage crops used in ruminant livestock production. The condensed tannin (CT) content, dry matter (DM) production, and persistence of these species are key characteristics of interest for future exploitation of these crops. Here we present field data on 19 varieties of L. corniculatus, 2 varieties of L. uliginosus and, additionally, a glasshouse experiment using 6 varieties of L. corniculatus and 2 varieties of L. uliginosus. Current methods for the quantification of condensed tannins in crop species are slow and labor intensive and are generally based upon polymer hydrolysis following the extraction of chlorophyll in a liquid phase. Presented here is a high-throughput protocol for condensed tannin quantification suitable for microtiter plates based upon the precipitation of condensed tannin polymers in complex with bovine serum albumin (BSA) with subsequent hydrolysis of precipates using butan 1-ol/ hydrochloric acid.

  4. Intellectual and non-intellectual determinants of high academic achievement – the contribution of personality traits to the assessment of high performance potential

    Directory of Open Access Journals (Sweden)

    Silvia Schubhart

    2013-09-01

    Full Text Available In this paper a study is presented which tries to explain and predict high academic achievement in children or adolescents on the basis of intellectual and non-intellectual determinants – in this case, performance relevant personality traits as well as the social environment of stimulation. The prognosis of high academic achievement is based on a new diagnostic model, the Viennese Diagnostic Model of High Achievement Potential, which undergoes its first empirical validation here. The results show impressive evidence that performance-relevant personality traits and categories of social environment of stimulation contribute to high academic achievement in children and adolescents of above-average intelligence.

  5. Improving Pervasive Positioning through Three-tier Cyber Foraging

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø; Kjærgaard, Mikkel Baun; Toftkjær, Thomas

    2011-01-01

    Cyber foraging is a pervasive computing technique where small, mobile devices offload resource intensive work to stronger, nearby surrogate computers in order to preserve energy and achieve better performance. The problem with relying only on local resources is, that the availability of such reso......Cyber foraging is a pervasive computing technique where small, mobile devices offload resource intensive work to stronger, nearby surrogate computers in order to preserve energy and achieve better performance. The problem with relying only on local resources is, that the availability...... of such resources may be scarce in many environments. In this paper we therefore argue that a third tier should be added when considering cyber foraging; namely cloud computing. By considering the local device, nearby surrogates, and the cloud when scheduling, the mobile device may be able to continue using remote...... the possible accuracy in many cases. In this paper we describe how a three tier cyber foraging approach can help improve the positioning capabilities of mobile devices. We demonstrate initial results for how such an approach applies to particle filtering-based GSM positioning....

  6. Food limitation of sea lion pups and the decline of forage off central and southern California.

    Science.gov (United States)

    McClatchie, Sam; Field, John; Thompson, Andrew R; Gerrodette, Tim; Lowry, Mark; Fiedler, Paul C; Watson, William; Nieto, Karen M; Vetter, Russell D

    2016-03-01

    California sea lions increased from approximately 50 000 to 340 000 animals in the last 40 years, and their pups are starving and stranding on beaches in southern California, raising questions about the adequacy of their food supply. We investigated whether the declining sea lion pup weight at San Miguel rookery was associated with changes in abundance and quality of sardine, anchovy, rockfish and market squid forage. In the last decade off central California, where breeding female sea lions from San Miguel rookery feed, sardine and anchovy greatly decreased in biomass, whereas market squid and rockfish abundance increased. Pup weights fell as forage food quality declined associated with changes in the relative abundances of forage species. A model explained 67% of the variance in pup weights using forage from central and southern California and 81% of the variance in pup weights using forage from the female sea lion foraging range. A shift from high to poor quality forage for breeding females results in food limitation of the pups, ultimately flooding animal rescue centres with starving sea lion pups. Our study is unusual in using a long-term, fishery-independent dataset to directly address an important consequence of forage decline on the productivity of a large marine predator. Whether forage declines are environmentally driven, are due to a combination of environmental drivers and fishing removals, or are due to density-dependent interactions between forage and sea lions is uncertain. However, declining forage abundance and quality was coherent over a large area (32.5-38° N) for a decade, suggesting that trends in forage are environmentally driven.

  7. Multiple-stage decisions in a marine central-place forager

    Science.gov (United States)

    Friedlaender, Ari S.; Johnston, David W.; Tyson, Reny B.; Kaltenberg, Amanda; Goldbogen, Jeremy A.; Stimpert, Alison K.; Curtice, Corrie; Hazen, Elliott L.; Halpin, Patrick N.; Read, Andrew J.; Nowacek, Douglas P.

    2016-01-01

    Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the central place and depth acts as the distance to prey. Although hypothesized that baleen whales will target the densest prey patches anywhere in the water column, how depth and density interact to influence foraging behaviour is poorly understood. We used multi-sensor archival tags and active acoustics to quantify Antarctic humpback whale foraging behaviour relative to prey. Our analyses reveal multi-stage foraging decisions driven by both krill depth and density. During daylight hours when whales did not feed, krill were found in deep high-density patches. As krill migrated vertically into larger and less dense patches near the surface, whales began to forage. During foraging bouts, we found that feeding rates (number of feeding lunges per hour) were greatest when prey was shallowest, and feeding rates decreased with increasing dive depth. This strategy is consistent with previous models of how air-breathing diving animals optimize foraging efficiency. Thus, humpback whales forage mainly when prey is more broadly distributed and shallower, presumably to minimize diving and searching costs and to increase feeding rates overall and thus foraging efficiency. Using direct measurements of feeding behaviour from animal-borne tags and prey availability from echosounders, our study demonstrates a multi-stage foraging process in a central place forager that we suggest acts to optimize overall efficiency by maximizing net energy gain over time. These data reveal a previously unrecognized level of complexity in predator–prey interactions and underscores the need to simultaneously measure prey distribution in marine central place

  8. Multiple-stage decisions in a marine central-place forager

    Science.gov (United States)

    Friedlaender, Ari S.; Johnston, David W.; Tyson, Reny B.; Kaltenberg, Amanda; Goldbogen, Jeremy A.; Stimpert, Alison K.; Curtice, Corrie; Hazen, Elliott L.; Halpin, Patrick N.; Read, Andrew J.; Nowacek, Douglas P.

    2016-05-01

    Air-breathing marine animals face a complex set of physical challenges associated with diving that affect the decisions of how to optimize feeding. Baleen whales (Mysticeti) have evolved bulk-filter feeding mechanisms to efficiently feed on dense prey patches. Baleen whales are central place foragers where oxygen at the surface represents the central place and depth acts as the distance to prey. Although hypothesized that baleen whales will target the densest prey patches anywhere in the water column, how depth and density interact to influence foraging behaviour is poorly understood. We used multi-sensor archival tags and active acoustics to quantify Antarctic humpback whale foraging behaviour relative to prey. Our analyses reveal multi-stage foraging decisions driven by both krill depth and density. During daylight hours when whales did not feed, krill were found in deep high-density patches. As krill migrated vertically into larger and less dense patches near the surface, whales began to forage. During foraging bouts, we found that feeding rates (number of feeding lunges per hour) were greatest when prey was shallowest, and feeding rates decreased with increasing dive depth. This strategy is consistent with previous models of how air-breathing diving animals optimize foraging efficiency. Thus, humpback whales forage mainly when prey is more broadly distributed and shallower, presumably to minimize diving and searching costs and to increase feeding rates overall and thus foraging efficiency. Using direct measurements of feeding behaviour from animal-borne tags and prey availability from echosounders, our study demonstrates a multi-stage foraging process in a central place forager that we suggest acts to optimize overall efficiency by maximizing net energy gain over time. These data reveal a previously unrecognized level of complexity in predator-prey interactions and underscores the need to simultaneously measure prey distribution in marine central place forager

  9. Qualitative research study of high-achieving females' life experiences impacting success

    Science.gov (United States)

    Butcher, Ann Patrice

    2003-07-01

    This qualitative study investigated the life experiences of five academically gifted female students in math and science in reflection of their elementary learning prior to enrollment at a prestigious science and mathematics high school. The elite high school limits admission to the state of Illinois' top students. The purpose of this study is to unfold the story of five academically gifted females in attendance at the elite high school reflecting on their life experiences in elementary school that contributed to their current academic success. Twelve female students, who at the time of this study were currently in their senior year (12th grade) of high school, were solicited from the top academic groups who are regarded by their teachers as highly successful in class. Students were selected as part of the study based on academic status, survey completion and interest in study, Caucasian and Asian ethnicity, locale of elementary school with preference given to the variety of school demographics---urban, suburban, and rural---further defined the group to the core group of five. All female participants were personally interviewed and communicated via Internet with the researcher. Parents and teachers completing surveys as well met the methodological requirements of triangulation. An emergent theme of paternal influence came from the research. Implications supported in the research drawn from this study to increase achievement of academically gifted females include: (a) proper early identification of learner strengths plays a role; (b) learning with appropriate intellectual peers is more important than learning with their age group; (c) teachers are the greatest force for excellent instruction; (d) effective teaching strategies include cooperative learning, multi-sensory learning, problem-based learning, and hands-on science; (e) rigor in math is important; (f) gender and stereotypes need not be barriers; (g) outside interests and activities are important for self

  10. Longitudinal Outcomes of Start Time Delay on Sleep, Behavior, and Achievement in High School

    Science.gov (United States)

    Thacher, Pamela V.; Onyper, Serge V.

    2016-01-01

    Study Objectives: To establish whether sleep, health, mood, behavior, and academics improved after a 45-minute delay in high school start time, and whether changes persisted longitudinally. Methods: We collected data from school records and student self-report across a number of domains at baseline (May 2012) and at two follow-up time points (November 2012 and May 2013), at a public high school in upstate New York. Students enrolled during academic years (AY) 2011–2012 and 2012–2013 completed the Pittsburgh Sleep Quality Index; the DASS-21; the “Owl-Lark” Scale; the Daytime Sleepiness Index; and a brief self-report of health. Reports from school records regarding attendance, tardiness, disciplinary violations, and academic performance were collected for AY 2010–2011 through 2013–2014. Results: Students delayed but did not extend their sleep period; we found lasting improvements in tardiness and disciplinary violations after the start-time delay, but no changes to other variables. At the first follow-up, students reported 20 minutes longer sleep, driven by later rise times and stable bed times. At the second follow-up, students maintained later rise times but delayed bedtimes, returning total sleep to baseline levels. A delay in rise time, paralleling the delay in the start time that occurred, resulted in less tardiness and decreased disciplinary incidents, but larger improvements to sleep patterns may be necessary to affect health, attendance, sleepiness, and academic performance. Conclusions: Later start times improved tardiness and disciplinary issues at this school district. A delay in start time may be a necessary but not sufficient means to increase sleep time and may depend on preexisting individual differences. Commentary: A commentary on this article appears in this issue on page 267. Citation: Thacher PV, Onyper SV. Longitudinal outcomes of start time delay on sleep, behavior, and achievement in high school. SLEEP 2016;39(2):271–281. PMID

  11. Relationships between high-stakes testing policies and student achievement after controlling for demographic factors in aggregated data.

    Directory of Open Access Journals (Sweden)

    Gregory J. Marchant

    2006-11-01

    Full Text Available With the mandate of No Child Left Behind, high-stakes achievement testing is firmly in place in every state. The few studies that have explored the effectiveness of high-stakes testing using NAEP scores have yielded mixed results. This study considered state demographic characteristics for each NAEP testing period in reading, writing, mathematics, and science from 1992 through 2002, in an effort to examine the relation of high-stakes testing policies to achievement and changes in achievement between testing periods. As expected, demographic characteristics and their changes were related significantly to most achievement outcomes, but high-stakes testing policies demonstrated few relationships with achievement. The few relationships between high-stakes testing and achievement or improvement in reading, writing, or science tended to appear only when demographic data were missing; and the minimal relationships with math achievement were consistent with findings in previous research. Considering the cost and potential unintended negative consequences, high-stakes testing policies seem to provide a questionable means of improving student learning.

  12. (Re)Defining the Narrative: High-Achieving Nontraditional Black Male Undergraduates at a Historically Black College and University

    Science.gov (United States)

    Goings, Ramon B.

    2016-01-01

    Using Harper's anti-deficit achievement framework as a theoretical guide, the purpose of this phenomenological study was to investigate the academic and social experiences of four nontraditional, high-achieving, Black male undergraduates attending one historically Black university. Findings show that the participants were intrinsically motivated…

  13. American High School Students from Different Ethnic Backgrounds: The Role of Parents and the Classroom in Achievement Motivation

    Science.gov (United States)

    Kim, Jung-In

    2015-01-01

    The purpose of this study was to investigate the relationships between ethnically diverse US high school students' (N = 331) perceptions of their parents' or classroom's motivating factors and their achievement motivation in their math class, connecting achievement goal orientation and self-determination theories. Two hypothesized path models were…

  14. Performance Assessment of High and Low Income Families through "Online RAW Achievement Battery Test" of Primary Grade Students

    Science.gov (United States)

    Ahmed, Tamim; Hanif, Maria

    2016-01-01

    This study is intended to investigate student's achievement capability among two families i.e. Low and High income families and designed for primary level learners. A Reading, Arithmetic and Writing (RAW) Achievement test that was developed as a part of another research study (Tamim Ahmed Khan, 2015) was adopted for this study. Both English medium…

  15. American High School Students from Different Ethnic Backgrounds: The Role of Parents and the Classroom in Achievement Motivation

    Science.gov (United States)

    Kim, Jung-In

    2015-01-01

    The purpose of this study was to investigate the relationships between ethnically diverse US high school students' (N = 331) perceptions of their parents' or classroom's motivating factors and their achievement motivation in their math class, connecting achievement goal orientation and self-determination theories. Two hypothesized path models were…

  16. A Multi-Institutional Study of the Relationship between High School Mathematics Achievement and Performance in Introductory College Statistics

    Science.gov (United States)

    Dupuis, Danielle N.; Medhanie, Amanuel; Harwell, Michael; LeBeau, Brandon; Monson, Debra; Post, Thomas R.

    2012-01-01

    In this study we examined the effects of prior mathematics achievement and completion of a commercially developed, National Science Foundation-funded, or University of Chicago School Mathematics Project high school mathematics curriculum on achievement in students' first college statistics course. Specifically, we examined the relationship between…

  17. The Impact of Principal Perception on Student Academic Climate and Achievement in High School: How Does It Measure Up?

    Science.gov (United States)

    Urick, Angela; Bowers, Alex J.

    2014-01-01

    The purpose of this study is to examine the independent direct effects of student and principal perceptions of academic climate on student achievement in high school. To date, few studies have considered the influence of principal perceptions of academic climate on student achievement. In the present study, we test a set of two-level hierarchical…

  18. (Re)Defining the Narrative: High-Achieving Nontraditional Black Male Undergraduates at a Historically Black College and University

    Science.gov (United States)

    Goings, Ramon B.

    2016-01-01

    Using Harper's anti-deficit achievement framework as a theoretical guide, the purpose of this phenomenological study was to investigate the academic and social experiences of four nontraditional, high-achieving, Black male undergraduates attending one historically Black university. Findings show that the participants were intrinsically motivated…

  19. A Multi-Institutional Study of the Relationship between High School Mathematics Achievement and Performance in Introductory College Statistics

    Science.gov (United States)

    Dupuis, Danielle N.; Medhanie, Amanuel; Harwell, Michael; LeBeau, Brandon; Monson, Debra; Post, Thomas R.

    2012-01-01

    In this study we examined the effects of prior mathematics achievement and completion of a commercially developed, National Science Foundation-funded, or University of Chicago School Mathematics Project high school mathematics curriculum on achievement in students' first college statistics course. Specifically, we examined the relationship between…

  20. Diet Overlap and Foraging Activity between Feral Pigs and Native Peccaries in the Pantanal.

    Science.gov (United States)

    Galetti, Mauro; Camargo, Hiléia; Siqueira, Tadeu; Keuroghlian, Alexine; Donatti, Camila I; Jorge, Maria Luisa S P; Pedrosa, Felipe; Kanda, Claudia Z; Ribeiro, Milton C

    2015-01-01

    Inter-specific competition is considered one of the main selective pressures affecting species distribution and coexistence. Different species vary in the way they forage in order to minimize encounters with their competitors and with their predators. However, it is still poorly known whether and how native species change their foraging behavior in the presence of exotic species, particularly in South America. Here we compare diet overlap of fruits and foraging activity period of two sympatric native ungulates (the white-lipped peccary, Tayassu pecari, and the collared peccary, Pecari tajacu) with the invasive feral pig (Sus scrofa) in the Brazilian Pantanal. We found high diet overlap between white-lipped peccaries and feral pigs, but low overlap between collared peccaries and feral pigs. Furthermore, we found that feral pigs may influence the foraging period of both native peccaries, but in different ways. In the absence of feral pigs, collared peccary activity peaks in the early evening, possibly allowing them to avoid white-lipped peccary activity peaks, which occur in the morning. In the presence of feral pigs, collared peccaries forage mostly in early morning, while white-lipped peccaries forage throughout the day. Our results indicate that collared peccaries may avoid foraging at the same time as white-lipped peccaries. However, they forage during the same periods as feral pigs, with whom they have lower diet overlap. Our study highlights how an exotic species may alter interactions between native species by interfering in their foraging periods.

  1. Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals.

    Science.gov (United States)

    Peterson, Sarah H; Ackerman, Joshua T; Costa, Daniel P

    2015-07-07

    Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200-1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ(13)C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation.

  2. Diet Overlap and Foraging Activity between Feral Pigs and Native Peccaries in the Pantanal.

    Directory of Open Access Journals (Sweden)

    Mauro Galetti

    Full Text Available Inter-specific competition is considered one of the main selective pressures affecting species distribution and coexistence. Different species vary in the way they forage in order to minimize encounters with their competitors and with their predators. However, it is still poorly known whether and how native species change their foraging behavior in the presence of exotic species, particularly in South America. Here we compare diet overlap of fruits and foraging activity period of two sympatric native ungulates (the white-lipped peccary, Tayassu pecari, and the collared peccary, Pecari tajacu with the invasive feral pig (Sus scrofa in the Brazilian Pantanal. We found high diet overlap between white-lipped peccaries and feral pigs, but low overlap between collared peccaries and feral pigs. Furthermore, we found that feral pigs may influence the foraging period of both native peccaries, but in different ways. In the absence of feral pigs, collared peccary activity peaks in the early evening, possibly allowing them to avoid white-lipped peccary activity peaks, which occur in the morning. In the presence of feral pigs, collared peccaries forage mostly in early morning, while white-lipped peccaries forage throughout the day. Our results indicate that collared peccaries may avoid foraging at the same time as white-lipped peccaries. However, they forage during the same periods as feral pigs, with whom they have lower diet overlap. Our study highlights how an exotic species may alter interactions between native species by interfering in their foraging periods.

  3. Marine foraging ecology influences mercury bioaccumulation in deep-diving northern elephant seals

    Science.gov (United States)

    Peterson, Sarah H.; Ackerman, Joshua T.; Costa, Daniel P.

    2015-01-01

    Mercury contamination of oceans is prevalent worldwide and methylmercury concentrations in the mesopelagic zone (200–1000 m) are increasing more rapidly than in surface waters. Yet mercury bioaccumulation in mesopelagic predators has been understudied. Northern elephant seals (Mirounga angustirostris) biannually travel thousands of kilometres to forage within coastal and open-ocean regions of the northeast Pacific Ocean. We coupled satellite telemetry, diving behaviour and stable isotopes (carbon and nitrogen) from 77 adult females, and showed that variability among individuals in foraging location, diving depth and δ13C values were correlated with mercury concentrations in blood and muscle. We identified three clusters of foraging strategies, and these resulted in substantially different mercury concentrations: (i) deeper-diving and offshore-foraging seals had the greatest mercury concentrations, (ii) shallower-diving and offshore-foraging seals had intermediate levels, and (iii) coastal and more northerly foraging seals had the lowest mercury concentrations. Additionally, mercury concentrations were lower at the end of the seven-month-long foraging trip (n = 31) than after the two-month- long post-breeding trip (n = 46). Our results indicate that foraging behaviour influences mercury exposure and mesopelagic predators foraging in the northeast Pacific Ocean may be at high risk for mercury bioaccumulation.

  4. A comparison of rural high school students in Germany with rural Tennessee high school students' mathematics and science achievement

    Science.gov (United States)

    Harding, R. Fredrick

    This descriptive study compared the science and mathematics aptitudes and achievement test scores for the final school year students in rural White County and Van Buren County, Tennessee with rural county students in Germany. In accordance with the previous research literature (Stevenson, 2002), German students outperformed U.S. students on The International Trends in Math and Science test (TIMSS). As reform in the U.S. education system has been underway, this study intended to compare German county student final school year performance with White County and Van Buren County (Grade 12) performance in science and mathematics. The entire populations of 176 White and Van Buren Counties senior high final school year students were compared with 120 school final year students from two rural German county high schools. The student responses to identical test and questionnaire items were compared using the t-test statistical analysis. In conclusion after t-test analyses, there was no significant difference (p>.05 level) in student attitudes on the 27 problem achievement and the 35 TIMSS questionnaire items between the sampled population of 120 German students compared with the population of 176 White and Van Buren students. Also, there was no statistically significant difference (p>.05 level) between the German, White, and Van Buren County rural science and math achievement in the TIMSS problem section of the final year test. Based on the research, recommendations to improve U.S. student scores to number one in the world include making changes in teaching methodology in mathematics and science; incorporating pamphlet lessons rather than heavily reliance on textbooks; focusing on problem solving; establishing an online clearinghouse for effective lessons; creating national standards in mathematics and science; matching students' course choices to job aspirations; tracking misbehaving students rather than mainstreaming them into the regular classroom; and designing

  5. Execution Plans for Cyber Foraging

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø

    2008-01-01

    Cyber foraging helps small devices perform heavy tasks by opportunistically discovering and utilising available resources (such as computation, storage, bandwidth, etc.) held by larger, nearby peers. This offloading is done in an ad-hoc manner, as larger machines will not always be within reach. ...

  6. Achieving conservation when opportunity costs are high: optimizing reserve design in Alberta's oil sands region.

    Directory of Open Access Journals (Sweden)

    Richard R Schneider

    Full Text Available Recent studies have shown that conservation gains can be achieved when the spatial distributions of biological benefits and economic costs are incorporated in the conservation planning process. Using Alberta, Canada, as a case study we apply these techniques in the context of coarse-filter reserve design. Because targets for ecosystem representation and other coarse-filter design elements are difficult to define objectively we use a trade-off analysis to systematically explore the relationship between conservation targets and economic opportunity costs. We use the Marxan conservation planning software to generate reserve designs at each level of conservation target to ensure that our quantification of conservation and economic outcomes represents the optimal allocation of resources in each case. Opportunity cost is most affected by the ecological representation target and this relationship is nonlinear. Although petroleum resources are present throughout most of Alberta, and include highly valuable oil sands deposits, our analysis indicates that over 30% of public lands could be protected while maintaining access to more than 97% of the value of the region's resources. Our case study demonstrates that optimal resource allocation can be usefully employed to support strategic decision making in the context of land-use planning, even when conservation targets are not well defined.

  7. Achieving conservation when opportunity costs are high: optimizing reserve design in Alberta's oil sands region.

    Science.gov (United States)

    Schneider, Richard R; Hauer, Grant; Farr, Dan; Adamowicz, W L; Boutin, Stan

    2011-01-01

    Recent studies have shown that conservation gains can be achieved when the spatial distributions of biological benefits and economic costs are incorporated in the conservation planning process. Using Alberta, Canada, as a case study we apply these techniques in the context of coarse-filter reserve design. Because targets for ecosystem representation and other coarse-filter design elements are difficult to define objectively we use a trade-off analysis to systematically explore the relationship between conservation targets and economic opportunity costs. We use the Marxan conservation planning software to generate reserve designs at each level of conservation target to ensure that our quantification of conservation and economic outcomes represents the optimal allocation of resources in each case. Opportunity cost is most affected by the ecological representation target and this relationship is nonlinear. Although petroleum resources are present throughout most of Alberta, and include highly valuable oil sands deposits, our analysis indicates that over 30% of public lands could be protected while maintaining access to more than 97% of the value of the region's resources. Our case study demonstrates that optimal resource allocation can be usefully employed to support strategic decision making in the context of land-use planning, even when conservation targets are not well defined.

  8. Untangling the debate surrounding strategies for achieving sustainable high coverage of insecticide-treated nets.

    Science.gov (United States)

    Stevens, Warren

    2005-01-01

    On the question of how to achieve the goal of long-term high utilisation of insecticide-treated nets (ITNs), most protagonists fall into one of two camps: free distribution or market development. The 'free distribution' camp argue that given the health benefit to be gained and lives saved, not to mention the relative cost effectiveness of ITNs, such an intervention should be provided free and paid for by governments or donors. In addition, they argue that it is unrealistic to ask the poorest of the population, who are often the ones at most risk, to pay for an ITN, and this risks producing greater inequalities in health. The market advocates counter that free distribution compromises sustainability, both in terms of demand and supply. Firstly they argue that, without a price, people will be less inclined to value ITNs. In turn this could mean lower utilisation, and a lower inclination to replace such an asset at the end of its useful life. In addition, on the supply side, without a price there is little chance of a local market developing for ITNs, although this would be the surest way to ensure a sustainable supply. It is hard to argue with either viewpoint, as both have merit. This article considers three major issues in the debate, and attempts to draw policy conclusions.

  9. Fair and Just Culture, Team Behavior, and Leadership Engagement: The Tools to Achieve High Reliability

    Science.gov (United States)

    Frankel, Allan S; Leonard, Michael W; Denham, Charles R

    2006-01-01

    Background Disparate health care provider attitudes about autonomy, teamwork, and administrative operations have added to the complexity of health care delivery and are a central factor in medicine's unacceptably high rate of errors. Other industries have improved their reliability by applying innovative concepts to interpersonal relationships and administrative hierarchical structures (Chandler 1962). In the last 10 years the science of patient safety has become more sophisticated, with practical concepts identified and tested to improve the safety and reliability of care. Objective Three initiatives stand out as worthy regarding interpersonal relationships and the application of provider concerns to shape operational change: The development and implementation of Fair and Just Culture principles, the broad use of Teamwork Training and Communication, and tools like WalkRounds that promote the alignment of leadership and frontline provider perspectives through effective use of adverse event data and provider comments. Methods Fair and Just Culture, Teamwork Training, and WalkRounds are described, and implementation examples provided. The argument is made that they must be systematically and consistently implemented in an integrated fashion. Conclusions There are excellent examples of institutions applying Just Culture principles, Teamwork Training, and Leadership WalkRounds—but to date, they have not been comprehensively instituted in health care organizations in a cohesive and interdependent manner. To achieve reliability, organizations need to begin thinking about the relationship between these efforts and linking them conceptually. PMID:16898986

  10. Relationships of cognitive and metacognitive learning strategies to mathematics achievement in four high-performing East Asian education systems.

    Science.gov (United States)

    Areepattamannil, Shaljan; Caleon, Imelda S

    2013-01-01

    The authors examined the relationships of cognitive (i.e., memorization and elaboration) and metacognitive learning strategies (i.e., control strategies) to mathematics achievement among 15-year-old students in 4 high-performing East Asian education systems: Shanghai-China, Hong Kong-China, Korea, and Singapore. In all 4 East Asian education systems, memorization strategies were negatively associated with mathematics achievement, whereas control strategies were positively associated with mathematics achievement. However, the association between elaboration strategies and mathematics achievement was a mixed bag. In Shanghai-China and Korea, elaboration strategies were not associated with mathematics achievement. In Hong Kong-China and Singapore, on the other hand, elaboration strategies were negatively associated with mathematics achievement. Implications of these findings are briefly discussed.

  11. Longitudinal Analysis of Chinese High School Student's Stress in School and Academic Achievement

    Science.gov (United States)

    Liu, Yangyang; Lu, Zuhong

    2011-01-01

    In previous research, few studies have examined the effects of adolescents' stress in school on the change rates of their academic achievement. In the present study, we seek to examine the longitudinal relationships between adolescents' stress in school and the change rates of their academic achievement. The results indicated that for those whose…

  12. Educational Expectations and Academic Achievement among Middle and High School Students

    Science.gov (United States)

    Bui, Khanh

    2007-01-01

    Using data from the National Education Longitudinal Study (NELS), this report examined the prospective relationships between educational expectations and academic achievement among students (n = 10,262) surveyed and tested in Grades 8, 10, and 12. Cross-lagged analyses indicated that between Grades 8 and 10 the path from achievement to…

  13. Motivational Factors Contributing to Turkish High School Students' Achievement in Gases and Chemical Reactions

    Science.gov (United States)

    Kadioglu, Cansel; Uzuntiryaki, Esen

    2008-01-01

    This study aimed to investigate the contribution of motivational factors to 10th grade students' achievement in gases and chemical reactions in chemistry. Three hundred fifty nine 10th grade students participated in the study. The Gases and Chemical Reactions Achievement Test and the Motivated Strategies for Learning Questionnaire were…

  14. Longitudinal Analysis of Chinese High School Student's Stress in School and Academic Achievement

    Science.gov (United States)

    Liu, Yangyang; Lu, Zuhong

    2011-01-01

    In previous research, few studies have examined the effects of adolescents' stress in school on the change rates of their academic achievement. In the present study, we seek to examine the longitudinal relationships between adolescents' stress in school and the change rates of their academic achievement. The results indicated that for those whose…

  15. Social Adaptation and Its Relationship to Achievement Motivation among High School Students in Jordan

    Science.gov (United States)

    AlZboon, Saleem Odeh

    2013-01-01

    The study amid at exploring and detecting the level of social adaptation and its relationship with the achievement motivation of the secondary school students in Jordan, the study sample consisted of 495 secondary school students in the province of Jerash, and to achieve the objective of this study comes the development of two tools: the first one…

  16. Achieving numerical accuracy and high performance using recursive tile LU factorization with partial pivoting

    KAUST Repository

    Dongarra, Jack

    2013-09-18

    The LU factorization is an important numerical algorithm for solving systems of linear equations in science and engineering and is a characteristic of many dense linear algebra computations. For example, it has become the de facto numerical algorithm implemented within the LINPACK benchmark to rank the most powerful supercomputers in the world, collected by the TOP500 website. Multicore processors continue to present challenges to the development of fast and robust numerical software due to the increasing levels of hardware parallelism and widening gap between core and memory speeds. In this context, the difficulty in developing new algorithms for the scientific community resides in the combination of two goals: achieving high performance while maintaining the accuracy of the numerical algorithm. This paper proposes a new approach for computing the LU factorization in parallel on multicore architectures, which not only improves the overall performance but also sustains the numerical quality of the standard LU factorization algorithm with partial pivoting. While the update of the trailing submatrix is computationally intensive and highly parallel, the inherently problematic portion of the LU factorization is the panel factorization due to its memory-bound characteristic as well as the atomicity of selecting the appropriate pivots. Our approach uses a parallel fine-grained recursive formulation of the panel factorization step and implements the update of the trailing submatrix with the tile algorithm. Based on conflict-free partitioning of the data and lockless synchronization mechanisms, our implementation lets the overall computation flow naturally without contention. The dynamic runtime system called QUARK is then able to schedule tasks with heterogeneous granularities and to transparently introduce algorithmic lookahead. The performance results of our implementation are competitive compared to the currently available software packages and libraries. For example

  17. Foraging Activity Pattern Is Shaped by Water Loss Rates in a Diurnal Desert Rodent.

    Science.gov (United States)

    Levy, Ofir; Dayan, Tamar; Porter, Warren P; Kronfeld-Schor, Noga

    2016-08-01

    Although animals fine-tune their activity to avoid excess heat, we still lack a mechanistic understanding of such behaviors. As the global climate changes, such understanding is particularly important for projecting shifts in the activity patterns of populations and communities. We studied how foraging decisions vary with biotic and abiotic pressures. By tracking the foraging behavior of diurnal desert spiny mice in their natural habitat and estimating the energy and water costs and benefits of foraging, we asked how risk management and thermoregulatory requirements affect foraging decisions. We found that water requirements had the strongest effect on the observed foraging decisions. In their arid environment, mice often lose water while foraging for seeds and cease foraging even at high energetic returns when water loss is high. Mice also foraged more often when energy expenditure was high and for longer times under high seed densities and low predation risks. Gaining insight into both energy and water balance will be crucial to understanding the forces exerted by changing climatic conditions on animal energetics, behavior, and ecology.

  18. EFFECT OF LEARNING WITH ABDUCTIVE-DEDUCTIVE STRATEGY TOWARDS THE ACHIEVEMENT OF REASONING ABILITY OF HIGH SCHOOL STUDENTS

    Directory of Open Access Journals (Sweden)

    Ali Shodikin

    2017-09-01

    Full Text Available The purpose of this study was to investigate the effect of learning with abductive-deductive strategy towards the achievement of mathematical reasoning abilities of high school students. Research carried out an experimental pretest-posttest design and the control group was not randomized in class XI student at one high school in Pati, Central Java, Indonesia. Data analysis was conducted quantitative research based on early mathematical ability categories (KAM and overall. The results showed that the achievement of mathematical reasoning abilities that students acquire learning abductive-deductive strategy better than students who received the expository learning. In more detail of KAM categories, only middle category that show achievement of mathematical reasoning abilities better. While in upper and under categories have the same reasoning abilities achievements. This research is expected teachers can encourage students to do abduction and deduction in the learning achievement of students’ mathematical reasoning abilities.

  19. Anion control as a strategy to achieve high-mobility and high-stability oxide thin-film transistors.

    Science.gov (United States)

    Kim, Hyun-Suk; Jeon, Sang Ho; Park, Joon Seok; Kim, Tae Sang; Son, Kyoung Seok; Seon, Jong-Baek; Seo, Seok-Jun; Kim, Sun-Jae; Lee, Eunha; Chung, Jae Gwan; Lee, Hyungik; Han, Seungwu; Ryu, Myungkwan; Lee, Sang Yoon; Kim, Kinam

    2013-01-01

    Ultra-definition, large-area displays with three-dimensional visual effects represent megatrend in the current/future display industry. On the hardware level, such a "dream" display requires faster pixel switching and higher driving current, which in turn necessitate thin-film transistors (TFTs) with high mobility. Amorphous oxide semiconductors (AOS) such as In-Ga-Zn-O are poised to enable such TFTs, but the trade-off between device performance and stability under illumination critically limits their usability, which is related to the hampered electron-hole recombination caused by the oxygen vacancies. Here we have improved the illumination stability by substituting oxygen with nitrogen in ZnO, which may deactivate oxygen vacancies by raising valence bands above the defect levels. Indeed, the stability under illumination and electrical bias is superior to that of previous AOS-based TFTs. By achieving both mobility and stability, it is highly expected that the present ZnON TFTs will be extensively deployed in next-generation flat-panel displays.

  20. Contact rate modulates foraging efficiency in leaf cutting ants.

    Science.gov (United States)

    Bouchebti, S; Ferrere, S; Vittori, K; Latil, G; Dussutour, A; Fourcassié, V

    2015-12-21

    Lane segregation is rarely observed in animals that move in bidirectional flows. Consequently, these animals generally experience a high rate of head-on collisions during their journeys. Although these collisions have a cost (each collision induces a delay resulting in a decrease of individual speed), they could also have a benefit by promoting information transfer between individuals. Here we explore the impact of head-on collisions in leaf-cutting ants moving on foraging trails by artificially decreasing the rate of head-on collisions between individuals. We show that head-on collisions do not influence the rate of recruitment in these ants but do influence foraging efficiency, i.e. the proportion of ants returning to the nest with a leaf fragment. Surprisingly, both unladen and laden ants returning to the nest participate in the modulation of foraging efficiency: foraging efficiency decreases when the rate of contacts with both nestbound laden or unladen ants decreases. These results suggest that outgoing ants are able to collect information from inbound ants even when these latter do not carry any leaf fragment and that this information can influence their foraging decisions when reaching the end of the trail.

  1. Genotypic Differences of Forage Crop Tolerance to Acid Soils

    Institute of Scientific and Technical Information of China (English)

    YANGYUAI; CHUXIANGYUN; 等

    1998-01-01

    Twenty eight species of forage crops were planted on acid soils derived from Quaternary red clay(pH4.16) and red sandstone(pH4.55) to study genotypic differences of the forage crops in tolerance to acid soils as affected by liming,phosporus and potassium fertilizer application.Eight forage species,Lolium nultiflorum L., Brachiaria decumbens,Digitaria sumtisii,Melinis minutiflora,Paspalum dilatatum,Paspalum wettsteinii,Sataria viridis Beanv and Shcep's Festuca,were highly toleran to acid soils,and grew relatively well in the tested soils without lime application,whereas most of the other 20 tested forage species such as Lolium perenne L., Meadow Festuca and Trifolium praense L. were intolerant to acid soil ,showing retarded growth when the soil pH was below 5.5 and significant increase in dry matter yields by phosphrus fertilizer application at soil pH 6.0 Results showed that large differences in tolerance to acid soils existed among the forage species,and tolerance of the froage species to acid soils might be closely associated with their tolerance to Al and P efficiency.

  2. Closing the Academic Achievement Gap on the California High School Exit Exam (CAHSEE) through Professional Learning Communities (PLC) Characteristics

    Science.gov (United States)

    Buenrostro, Samuel

    2012-01-01

    Purpose: The purpose of this study was to determine the degree of importance that DuFour's nine characteristics of highly effective schools have on closing the academic achievement gap on the California High School Exit Exam, as perceived by high school principals. The study also examined the strategies believed to be most important in developing…

  3. Closing the Academic Achievement Gap on the California High School Exit Exam (CAHSEE) through Professional Learning Communities (PLC) Characteristics

    Science.gov (United States)

    Buenrostro, Samuel

    2012-01-01

    Purpose: The purpose of this study was to determine the degree of importance that DuFour's nine characteristics of highly effective schools have on closing the academic achievement gap on the California High School Exit Exam, as perceived by high school principals. The study also examined the strategies believed to be most important in…

  4. When Michaelis and Menten met Holling: towards a mechanistic theory of plant nutrient foraging behaviour.

    Science.gov (United States)

    McNickle, Gordon G; Brown, Joel S

    2014-10-22

    Plants are adept at assessing and responding to nutrients in soil, and generally proliferate roots into nutrient-rich patches. An analogy between this growth response and animal foraging movement is often drawn, but because of differences between plants and animals it has not always been clear how to directly apply existing foraging theory to plants. Here we suggest one way to unite pre-existing ideas in plant nutrient uptake with foraging theory. First, we show that the Michaelis-Menten equation used by botanists and the Holling disc equation used by zoologists are actually just rearrangements of the same functional response. This mathematical unity permits the translation of existing knowledge about the nutrient uptake physiology of plants into the language of foraging behaviour, and as a result gives botanists direct access to foraging theory. Second, we developed a model of root foraging precision based on the Holling disc equation and the marginal value theorem, and parameterize it from the literature. The model predicts (i) generally plants should invest in higher quality patches compared to lower quality patches, and as patch background-contrast increases; (ii) low encounter rates between roots and nutrients result in high root foraging precision; and (iii) low handling times for nutrients should result in high root foraging precision. The available data qualitatively support these predictions. Third, to parameterize the model above we undertook a review of the literature. From that review we obtained parameter estimates for nitrate and/or ammonium uptake for 45 plant species from 38 studies. We observe that the parameters ranged over six orders of magnitude, there was no trade-off in foraging ability for nitrate versus ammonium: plants that were efficient foragers for one form of nitrogen were efficient foragers for the other, and there was also no phylogenetic signal in the parameter estimates. Published by Oxford University Press on behalf of the Annals

  5. Behavioral suites mediate group-level foraging dynamics in communities of tropical stingless bees.

    Science.gov (United States)

    Lichtenberg, E M; Imperatriz-Fonseca, V L; Nieh, J C

    2010-02-01

    Competition for floral resources is a key force shaping pollinator communities, particularly among social bees. The ability of social bees to recruit nestmates for group foraging is hypothesized to be a major factor in their ability to dominate rich resources such as mass-flowering trees. We tested the role of group foraging in attaining dominance by stingless bees, eusocial tropical pollinators that exhibit high diversity in foraging strategies. We provide the first experimental evidence that meliponine group foraging strategies, large colony sizes and aggressive behavior form a suite of traits that enable colonies to improve dominance of rich resources. Using a diverse assemblage of Brazilian stingless bee species and an array of artificial "flowers" that provided a sucrose reward, we compared species' dominance and visitation under unrestricted foraging conditions and with experimental removal of group-foraging species. Dominance does not vary with individual body size, but rather with foraging group size. Species that recruit larger numbers of nestmates (Scaptotrigona aff. depilis, Trigona hyalinata, Trigona spinipes) dominated both numerically (high local abundance) and behaviorally (controlling feeders). Removal of group-foraging species increased feeding opportunities for solitary foragers (Frieseomelitta varia, Melipona quadrifasciata and Nannotrigona testaceicornis). Trigona hyalinata always dominated under unrestricted conditions. When this species was removed, T. spinipes or S. aff. depilis controlled feeders and limited visitation by solitary-foraging species. Because bee foraging patterns determine plant pollination success, understanding the forces that shape these patterns is crucial to ensuring pollination of both crops and natural areas in the face of current pollinator declines. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00040-009-0055-8) contains supplementary material, which is available to authorized

  6. Forage Polyphenol Oxidase and Ruminant Livestock Nutrition

    Directory of Open Access Journals (Sweden)

    Michael Richard F. Lee

    2014-12-01

    Full Text Available Polyphenol oxidase (PPO is associated with the detrimental effect of browning fruit and vegetables, however interest within PPO containing forage crops has grown since the brownng reaction was associated with reduced nitrogen (N losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage increased the quality of protein, improving N-use efficiency (NUE when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalysing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP. If the protein is an enzyme the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase un-degraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated with entrapment within PBP reducing access to microbial lipases or differences in rumen digestion kinetics of red clover.

  7. Family socioeconomic status, family health, and changes in students' math achievement across high school: A mediational model.

    Science.gov (United States)

    Barr, Ashley Brooke

    2015-09-01

    In response to recent calls to integrate understandings of socioeconomic disparities in health with understandings of socioeconomic disparities in academic achievement, this study tested a mediational model whereby family socioeconomic status predicted gains in academic achievement across high school through its impact on both student and parent health. Data on over 8000 high school students in the U.S. were obtained from wave 1 (2009-2010) and wave 2 (2012) of the High School Longitudinal Study of 2009 (HSLS:09), and structural equation modeling with latent difference scores was used to determine the role of family health problems in mediating the well-established link between family SES and gains in academic achievement. Using both static and dynamic indicators of family SES, support was found for this mediational model. Higher family SES in 9th grade reduced the probability of students and their parents experiencing a serious health problem in high school, thereby promoting growth in academic achievement. In addition, parent and student health problems mediated the effect of changes in family SES across high school on math achievement gains. Results emphasize the importance of considering the dynamic nature of SES and that both student and parent health should be considered in understanding SES-related disparities in academic achievement. This relational process provides new mechanisms for understanding the intergenerational transmission of socioeconomic status and the status attainment process more broadly. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Corn in consortium with forages

    Directory of Open Access Journals (Sweden)

    Cássia Maria de Paula Garcia

    2013-12-01

    Full Text Available The basic premises for sustainable agricultural development with focus on rural producers are reducing the costs of production and aggregation of values through the use crop-livestock system (CLS throughout the year. The CLS is based on the consortium of grain crops, especially corn with tropical forages, mainly of the genus Panicum and Urochloa. The study aimed to evaluate the grain yield of irrigated corn crop intercropped with forage of the genus Panicum and Urochloa. The experiment was conducted at the Fazenda de Ensino, Pesquisa e Extensão – FEPE  of the Faculdade de Engenharia - UNESP, Ilha Solteira in an Oxisol in savannah conditions and in the autumn winter of 2009. The experimental area was irrigated by a center pivot and had a history of no-tillage system for 8 years. The corn hybrid used was simple DKB 390 YG at distances of 0.90 m. The seeds of grasses were sown in 0.34 m spacing in the amount of 5 kg ha-1, they were mixed with fertilizer minutes before sowing  and placed in a compartment fertilizer seeder and fertilizers were mechanically deposited in the soil at a depth of 0.03 m. The experimental design used was a randomized block with four replications and five treatments: Panicum maximum cv. Tanzania sown during the nitrogen fertilization (CTD of the corn; Panicum maximum cv. Mombaça sown during the nitrogen fertilization (CMD of the corn; Urochloa brizantha cv. Xaraés sown during the occasion of nitrogen fertilization (CBD of the corn; Urochloa ruziziensis cv. Comumsown during the nitrogen fertilization (CRD of the corn and single corn (control. The production components of corn: plant population per hectare (PlPo, number of ears per hectare (NE ha-1, number of rows per ear (NRE, number of kernels per row on the cob (NKR, number of grain in the ear (NGE and mass of 100 grains (M100G were not influenced by consortium with forage. Comparing grain yield (GY single corn and maize intercropped with forage of the genus Panicum

  9. Feeding-Related Traits Are Affected by Dosage of the foraging Gene in Drosophila melanogaster.

    Science.gov (United States)

    Allen, Aaron M; Anreiter, Ina; Neville, Megan C; Sokolowski, Marla B

    2017-02-01

    Nutrient acquisition and energy storage are critical parts of achieving metabolic homeostasis. The foraging gene in Drosophila melanogaster has previously been implicated in multiple feeding-related and metabolic traits. Before foraging's functions can be further dissected, we need a precise genetic null mutant to definitively map its amorphic phenotypes. We used homologous recombination to precisely delete foraging, generating the for(0) null allele, and used recombineering to reintegrate a full copy of the gene, generating the {for(BAC)} rescue allele. We show that a total loss of foraging expression in larvae results in reduced larval path length and food intake behavior, while conversely showing an increase in triglyceride levels. Furthermore, varying foraging gene dosage demonstrates a linear dose-response on these phenotypes in relation to foraging gene expression levels. These experiments have unequivocally proven a causal, dose-dependent relationship between the foraging gene and its pleiotropic influence on these feeding-related traits. Our analysis of foraging's transcription start sites, termination sites, and splicing patterns using rapid amplification of cDNA ends (RACE) and full-length cDNA sequencing, revealed four independent promoters, pr1-4, that produce 21 transcripts with nine distinct open reading frames (ORFs). The use of alternative promoters and alternative splicing at the foraging locus creates diversity and flexibility in the regulation of gene expression, and ultimately function. Future studies will exploit these genetic tools to precisely dissect the isoform- and tissue-specific requirements of foraging's functions and shed light on the genetic control of feeding-related traits involved in energy homeostasis. Copyright © 2017 by the Genetics Society of America.

  10. Effects of the juvenile hormone analogue methoprene on rate of behavioural development, foraging performance and navigation in honey bees (Apis mellifera).

    Science.gov (United States)

    Chang, Lun-Hsien; Barron, Andrew B; Cheng, Ken

    2015-06-01

    Worker honey bees change roles as they age as part of a hormonally regulated process of behavioural development that ends with a specialised foraging phase. The rate of behavioural development is highly plastic and responsive to changes in colony condition such that forager losses, disease or nutritional stresses accelerate behavioural development and cause an early onset of foraging in workers. It is not clear to what degree the behavioural development of workers can be accelerated without there being a cost in terms of reduced foraging performance. Here, we compared the foraging performance of bees induced to accelerate their behavioural development by treatment with the juvenile hormone analogue methoprene with that of controls that developed at a normal rate. Methoprene treatment accelerated the onset of both flight and foraging behaviour in workers, but it also reduced foraging span, the total time spent foraging and the number of completed foraging trips. Methoprene treatment did not alter performance in a short-range navigation task, however. These data indicate a limitation to the physiological plasticity of bees, and a trade off between forager performance and the speed at which bees begin foraging. Chronic stressors will be expected to reduce the mean age of the foraging force, and therefore also reduce the efficiency of the foraging force. This interaction may explain why honey bee colonies react to sustained stressors with non-linear population decline.

  11. Academic Achievement Trajectories of Homeless and Highly Mobile Students: Resilience in the Context of Chronic and Acute Risk

    Science.gov (United States)

    Cutuli, J. J.; Desjardins, Christopher David; Herbers, Janette E.; Long, Jeffrey D.; Heistad, David; Chan, Chi-Keung; Hinz, Elizabeth; Masten, Ann S.

    2012-01-01

    Analyses examined academic achievement data across 3rd through 8th grades (N = 26,474), comparing students identified as homeless or highly mobile (HHM) to other students in the federal free meal program (FM), reduced-price meals (RM), or neither (General). Achievement was lower as a function of rising risk status (General > RM > FM > HHM). Achievement gaps appeared stable or widened between HHM students and lower-risk groups. Math and reading achievement were lower and growth in math was slower in years of HHM identification, suggesting acute consequences of residential instability. Nonetheless, 45% of HHM students scored within or above the average range, suggesting academic resilience. Results underscore the need for research on risk and resilience processes among HHM students to address achievement disparities. PMID:23110492

  12. Influence of Strategy of Learning and Achievement Motivation of Learning Achievement Class VIII Students of State Junior High School in District Blitar

    Science.gov (United States)

    Ayundawati, Dyah; Setyosari, Punaji; Susilo, Herawati; Sihkabuden

    2016-01-01

    This study aims for know influence of problem-based learning strategies and achievement motivation on learning achievement. The method used in this research is quantitative method. The instrument used in this study is two fold instruments to measure moderator variable (achievement motivation) and instruments to measure the dependent variable (the…

  13. Foraging decisions in wild versus domestic Mus musculus: What does life in the lab select for?

    Science.gov (United States)

    Troxell-Smith, Sandra M; Tutka, Michal J; Albergo, Jessica M; Balu, Deebika; Brown, Joel S; Leonard, John P

    2016-01-01

    What does domestication select for in terms of foraging and anti-predator behaviors? We applied principles of patch use and foraging theory to test foraging strategies and fear responses of three strains of Mus musculus: wild-caught, control laboratory, and genetically modified strains. Foraging choices were quantified using giving-up densities (GUDs) under three foraging scenarios: (1) patches varying in microhabitat (covered versus open), and initial resource density (low versus high); (2) daily variation in auditory cues (aerial predators and control calls); (3) patches with varying seed aggregations. Overall, both domestic strains harvested significantly more food than wild mice. Each strain revealed a significant preference for foraging under cover compared to the open, and predator calls had no detectable effects on foraging. Both domestic strains biased their harvest toward high quality patches; wild mice did not. In terms of exploiting favorable and avoiding unfavorable distributions of seeds within patches, the lab strain performed best, the wild strain worst, and the mutant strain in between. Our study provides support for hypothesis that domestic animals have more energy-efficient foraging strategies than their wild counterparts, but retain residual fear responses. Furthermore, patch-use studies can reveal the aptitudes and priorities of both domestic and wild animals.

  14. Bumble bee nest abundance, foraging distance, and host-plant reproduction: implications for management and conservation.

    Science.gov (United States)

    Geib, Jennifer C; Strange, James P; Galenj, Candace

    2015-04-01

    Recent reports of global declines in pollinator species imply an urgent need to assess the abundance of native pollinators and density-dependent benefits for linked plants. In this study, we investigated (1) pollinator nest distributions and estimated colony abundances, (2) the relationship between abundances of foraging workers and the number of nests they represent, (3) pollinator foraging ranges, and (4) the relationship between pollinator abundance and plant reproduction. We examined these questions in an alpine ecosystem in the Colorado Rocky Mountains, focusing on four alpine bumble bee species (Bombus balteatus, B. flavifrons, B. bifarius, and B. sylvicola), and two host plants that differ in their degrees of pollinator specialization (Trifolium dasyphyllum and T. parryi). Using microsatellites, we found that estimated colony abundances among Bombus species ranged from ~18 to 78 colonies/0.01 km2. The long-tongued species B. balteatus was most common, especially high above treeline, but the subalpine species B. bifarius was unexpectedly abundant for this elevation range. Nests detected among sampled foragers of each species were correlated with the number of foragers caught. Foraging ranges were smaller than expected for all Bombus species, ranging from 25 to 110 m. Fruit set for the specialized plant, Trifolium parryi, was positively related to the abundance of its Bombus pollinator. In contrast, fruit set for the generalized plant, T. dasyphyllum, was related to abundance of all Bombus species. Because forager abundance was related to nest abundance of each Bombus species and was an equally effective predictor of plant fecundity, forager inventories are probably suitable for assessing the health of outcrossing plant populations. However, nest abundance, rather than forager abundance, better reflects demographic and genetic health in populations of eusocial pollinators such as bumble bees. Development of models incorporating the parameters we have measured

  15. Forage polyphenol oxidase and ruminant livestock nutrition.

    Science.gov (United States)

    Lee, Michael R F

    2014-01-01

    Polyphenol oxidase (PPO) is predominately associated with the detrimental effect of browning fruit and vegetables, however, interest within PPO containing forage crops (crops to be fed to animals) has grown since the browning reaction was associated with reduced nitrogen (N) losses in silo and the rumen. The reduction in protein breakdown in silo of red clover (high PPO forage) increased the quality of protein, improving N-use efficiency [feed N into product N (e.g., Milk): NUE] when fed to ruminants. A further benefit of red clover silage feeding is a significant reduction in lipolysis (cleaving of glycerol-based lipid) in silo and an increase in the deposition of beneficial C18 polyunsaturated fatty acid (PUFA) in animal products, which has also been linked to PPO activity. PPOs protection of plant protein and glycerol based-PUFA in silo is related to the deactivation of plant proteases and lipases. This deactivation occurs through PPO catalyzing the conversion of diphenols to quinones which bind with cellular nucleophiles such as protein reforming a protein-bound phenol (PBP). If the protein is an enzyme (e.g., protease or lipase) the complexing denatures the enzyme. However, PPO is inactive in the anaerobic rumen and therefore any subsequent protection of plant protein and glycerol based-PUFA in the rumen must be as a result of events that occurred to the forage pre-ingestion. Reduced activity of plant proteases and lipases would have little effect on NUE and glycerol based-PUFA in the rumen due to the greater concentration of rumen microbial proteases and lipases. The mechanism for PPOs protection of plant protein in the rumen is a consequence of complexing plant protein, rather than protease deactivation per se. These complexed proteins reduce protein digestibility in the rumen and subsequently increase undegraded dietary protein flow to the small intestine. The mechanism for protecting glycerol-based PUFA has yet to be fully elucidated but may be associated

  16. Differential regulation of the foraging gene associated with task behaviors in harvester ants.

    Science.gov (United States)

    Ingram, Krista K; Kleeman, Lindsay; Peteru, Swetha

    2011-08-10

    The division of labor in social insect colonies involves transitions by workers from one task to another and is critical to the organization and ecological success of colonies. The differential regulation of genetic pathways is likely to be a key mechanism involved in plasticity of social insect task behavior. One of the few pathways implicated in social organization involves the cGMP-activated protein kinase gene, foraging, a gene associated with foraging behavior in social insect species. The association of the foraging gene with behavior is conserved across diverse species, but the observed expression patterns and proposed functions of this gene vary across taxa. We compared the protein sequence of foraging across social insects and explored whether the differential regulation of this gene is associated with task behaviors in the harvester ant, Pogonomyrmex occidentalis. Phylogenetic analysis of the coding region of the foraging gene reveals considerable conservation in protein sequence across insects, particularly among hymenopteran species. The absence of amino acid variation in key active and binding sites suggests that differences in behaviors associated with this gene among species may be the result of changes in gene expression rather than gene divergence. Using real time qPCR analyses with a harvester ant ortholog to foraging (Pofor), we found that the brains of harvester ant foragers have a daily fluctuation in expression of foraging with mRNA levels peaking at midday. In contrast, young workers inside the nest have low levels of Pofor mRNA with no evidence of daily fluctuations in expression. As a result, the association of foraging expression with task behavior within a species changes depending on the time of day the individuals are sampled. The amino acid protein sequence of foraging is highly conserved across social insects. Differences in foraging behaviors associated with this gene among social insect species are likely due to differences in gene

  17. Differential regulation of the foraging gene associated with task behaviors in harvester ants

    Directory of Open Access Journals (Sweden)

    Kleeman Lindsay

    2011-08-01

    Full Text Available Abstract Background The division of labor in social insect colonies involves transitions by workers from one task to another and is critical to the organization and ecological success of colonies. The differential regulation of genetic pathways is likely to be a key mechanism involved in plasticity of social insect task behavior. One of the few pathways implicated in social organization involves the cGMP-activated protein kinase gene, foraging, a gene associated with foraging behavior in social insect species. The association of the foraging gene with behavior is conserved across diverse species, but the observed expression patterns and proposed functions of this gene vary across taxa. We compared the protein sequence of foraging across social insects and explored whether the differential regulation of this gene is associated with task behaviors in the harvester ant, Pogonomyrmex occidentalis. Results Phylogenetic analysis of the coding region of the foraging gene reveals considerable conservation in protein sequence across insects, particularly among hymenopteran species. The absence of amino acid variation in key active and binding sites suggests that differences in behaviors associated with this gene among species may be the result of changes in gene expression rather than gene divergence. Using real time qPCR analyses with a harvester ant ortholog to foraging (Pofor, we found that the brains of harvester ant foragers have a daily fluctuation in expression of foraging with mRNA levels peaking at midday. In contrast, young workers inside the nest have low levels of Pofor mRNA with no evidence of daily fluctuations in expression. As a result, the association of foraging expression with task behavior within a species changes depending on the time of day the individuals are sampled. Conclusions The amino acid protein sequence of foraging is highly conserved across social insects. Differences in foraging behaviors associated with this gene among

  18. Investigate Factor Effecting Of Students’ Achievement on High School Entrance Exam-(SBS Respect to the Different Variables

    Directory of Open Access Journals (Sweden)

    Mustafa METİN

    2013-04-01

    Full Text Available The aim of study is to investigate factor affecting of secondary school students’ achievement on high school entrance exam (SBS respect to the different variables. The study was carried out at fall semester of 2012 with 991 students educating primary schools in Artvin. In this study survey method was used and data gathered with questionnaire consists of 40 items. As a result of study, it was determinate that effects of family, educational facilities, teachers and personal characters on students’ achievement are at high level. There is no different between gender and students achievement (p>0.05, although there are different between grade level, family incomes, graduation types of mother and father and students achievement (p<0.05.

  19. In situ Rumen Degradation Kinetics of High-Protein Forage Crops in Temperate Climates Cinética de Degradación Ruminal in situ en Forrajes de Alto Contenido Proteico en Clima Templado

    Directory of Open Access Journals (Sweden)

    Ximena Valderrama L.

    2011-12-01

    Full Text Available The present study was conducted to evaluate the nutritional value and in situ degradation kinetics of eight high protein forage crops: alfalfa (Medicago sativa L., forage oat (Avena sativa L., mixed pasture, and ryegrass (Lolium multiflorum Lam. pasture in early vegetative stages, two forage lupins (Lupinus albus L. in early bloom stages, sugar beet (Beta vulgaris L. and kale (Brassica napus var. pabularia (DC. Rchb. leaves at root maturity. Dry matter (DM and crude protein (CP degradation kinetics were evaluated by the nylon bag technique through the in situ procedure described by 0rskov and MacDonald (1979 using three ruminally cannulated sheep. Chemical composition of the forage crops showed on average 13.7% DM; 21.4% CP; 31.5% neutral detergent fiber (NDF; 17.7% crude fiber (CF, 80.6% digestibility of organic matter (DOMD and 12.13 MJ kg-1 metabolizable energy (ME. The high total degradability of forage crops reported here (> 87% DM; > 93% CP can be associated with the presence of large quantities of fraction a (> 34% DMa; > 29% CPa and high degradability of fraction b, resulting in low amounts of undegradable fraction (U (7.02% DM and 3.55% CP. Correlations between CPb and DMb degradability (r = 0.79 and CPc and DMc degradation rates (r = 0.78 were high, however differences in c were not explained by differences in CP or NDF contents, nor by the amounts of a or b fractions. Degradation for DM and CP during the first 6 h of incubation was strongly and inversely correlated to b (36 h (r = 0.93 (P El presente estudio se desarrolló con el objetivo de evaluar el valor nutricional y la cinética de degradación in situ de ocho forrajes de alto valor proteico: alfalfa (Medicago sativa L., avena (Avena sativa L., pastos mixtos y pastos de ballica (Lolium multiflorum Lam., en las primeras etapas vegetativas, dos lupinos forrajeros (Lupinus albus L. en etapas inicio de la floración, hojas de remolacha azucarera (Beta vulgaris L. y de col (Brassica

  20. Behavior problems at ages 6 and 11 and high school academic achievement: longitudinal latent variable modeling.

    Science.gov (United States)

    Breslau, Naomi; Breslau, Joshua; Miller, Elizabeth; Raykov, Tenko

    2011-02-28

    Previous studies documented long-run effects of behavior problems at the start of school on academic achievement. However, these studies did not examine whether the observed effects of early behavior problems are explained by more proximate behavior problems, given the tendency of children's behavior problems to persist. Latent variable modeling was applied to estimate the effects of behavior problems at ages 6 and 11 on academic achievement at age 17, using data from a longitudinal study (n=823). Behavior problems at ages 6 and 11, each stage independently of the other, predicted lower math and reading test scores at age 17, controlling for intelligence quotient (IQ), birth weight, maternal characteristics, family and community environment, and taking into account behavior problems at age 17. Behavior problems at the start of school, independent of later behavior problems, exert lingering effects on achievement by impeding the acquisition of cognitive skills that are the foundation for later academic progress.

  1. Markets, voucher subsidies and free nets combine to achieve high bed net coverage in rural Tanzania

    Directory of Open Access Journals (Sweden)

    Gerrets Rene PM

    2008-06-01

    Full Text Available Abstract Background Tanzania has a well-developed network of commercial ITN retailers. In 2004, the government introduced a voucher subsidy for pregnant women and, in mid 2005, helped distribute free nets to under-fives in small number of districts, including Rufiji on the southern coast, during a child health campaign. Contributions of these multiple insecticide-treated net delivery strategies existing at the same time and place to coverage in a poor rural community were assessed. Methods Cross-sectional household survey in 6,331 members of randomly selected 1,752 households of 31 rural villages of Demographic Surveillance System in Rufiji district, Southern Tanzania was conducted in 2006. A questionnaire was administered to every consenting respondent about net use, treatment status and delivery mechanism. Findings Net use was 62.7% overall, 87.2% amongst infants (0 to1 year, 81.8% amongst young children (>1 to 5 years, 54.5% amongst older children (6 to 15 years and 59.6% amongst adults (>15 years. 30.2% of all nets had been treated six months prior to interview. The biggest source of nets used by infants was purchase from the private sector with a voucher subsidy (41.8%. Half of nets used by young children (50.0% and over a third of those used by older children (37.2% were obtained free of charge through the vaccination campaign. The largest source of nets amongst the population overall was commercial purchase (45.1% use and was the primary means for protecting adults (60.2% use. All delivery mechanisms, especially sale of nets at full market price, under-served the poorest but no difference in equity was observed between voucher-subsidized and freely distributed nets. Conclusion All three delivery strategies enabled a poor rural community to achieve net coverage high enough to yield both personal and community level protection for the entire population. Each of them reached their relevant target group and free nets only temporarily

  2. Starvation dynamics of a greedy forager

    Science.gov (United States)

    Bhat, U.; Redner, S.; Bénichou, O.

    2017-07-01

    We investigate the dynamics of a greedy forager that moves by random walking in an environment where each site initially contains one unit of food. Upon encountering a food-containing site, the forager eats all the food there and can subsequently hop an additional S steps without food before starving to death. Upon encountering an empty site, the forager goes hungry and comes one time unit closer to starvation. We investigate the new feature of forager greed; if the forager has a choice between hopping to an empty site or to a food-containing site in its nearest neighborhood, it hops preferentially towards food. If the neighboring sites all contain food or are all empty, the forager hops equiprobably to one of these neighbors. Paradoxically, the lifetime of the forager can depend non-monotonically on greed, and the sense of the non-monotonicity is opposite in one and two dimensions. Even more unexpectedly, the forager lifetime in one dimension is substantially enhanced when the greed is negative; here the forager tends to avoid food in its local neighborhood. We also determine the average amount of food consumed at the instant when the forager starves. We present analytic, heuristic, and numerical results to elucidate these intriguing phenomena.

  3. Foraging currencies, metabolism and behavioural routines.

    Science.gov (United States)

    Houston, Alasdair I; McNamara, John M

    2014-01-01

    A fundamental issue in foraging theory is whether it is possible to find a simple currency that characterizes foraging behaviour. If such a currency exists, then it is tempting to argue that the selective forces that have shaped the evolution of foraging behaviour have been understood. We review previous work on currencies for the foraging behaviour of an animal that maximizes total energy gained. In many circumstances, it is optimal to maximize a suitably modified form of efficiency. We show how energy gain, predation and damage can be combined in a single currency based on reproductive value. We draw attention to the idea that hard work may have an adverse effect on an animal's condition. We develop a model of optimal foraging over a day when a forager's state consists of its energy reserves and its condition. Optimal foraging behaviour in our model depends on energy reserves, condition and time of day. The pattern of optimal behaviour depends strongly on assumptions about the probability that the forager is killed by a predator. If condition is important, no simple currency characterizes foraging behaviour, but behaviour can be understood in terms of the maximization of reproductive value. It may be optimal to adopt a foraging option that results in a rate of energy expenditure that is less than the rate associated with maximizing efficiency.

  4. Geographic profiling and animal foraging.

    Science.gov (United States)

    Le Comber, Steven C; Nicholls, Barry; Rossmo, D Kim; Racey, Paul A

    2006-05-21

    Geographic profiling was originally developed as a statistical tool for use in criminal cases, particularly those involving serial killers and rapists. It is designed to help police forces prioritize lists of suspects by using the location of crime scenes to identify the areas in which the criminal is most likely to live. Two important concepts are the buffer zone (criminals are less likely to commit crimes in the immediate vicinity of their home) and distance decay (criminals commit fewer crimes as the distance from their home increases). In this study, we show how the techniques of geographic profiling may be applied to animal data, using as an example foraging patterns in two sympatric colonies of pipistrelle bats, Pipistrellus pipistrellus and P. pygmaeus, in the northeast of Scotland. We show that if model variables are fitted to known roost locations, these variables may be used as numerical descriptors of foraging patterns. We go on to show that these variables can be used to differentiate patterns of foraging in these two species.

  5. The Effects of College Counseling on High-Achieving, Low-Income Students. NBER Working Paper No. 16359

    Science.gov (United States)

    Avery, Christopher

    2010-01-01

    This paper reports the results of a pilot study, using a randomized controlled trial to provide college counseling to high-achieving students from relatively poor families. We followed 107 high school seniors through the college admissions process in 2006-2007; we selected 52 of these students at random, offering them ten hours of individualized…

  6. The Influence of the Antecedent Variable on the Teachers' Performance through Achievement Motivation in Senior High School

    Science.gov (United States)

    Dewi, Erni R.; Bundu, Patta; Tahmir, Suradi

    2016-01-01

    This study aims at analysing whether the antecedent variable directly affects the performance of the high school teachers or not. In addition, this research strives to find out whether the antecedent variable indirectly affects the teachers' performance through the achievement motivation of the high school teachers. It was a quantitative research…

  7. The Effect of Task-Based Language Teaching on Motivation and Grammatical Achievement of EFL Junior High School Students

    Science.gov (United States)

    NamazianDost, Islam; Bohloulzadeh, Ghassem; Pazhakh, Abdolreza

    2017-01-01

    This research sought to investigate the effect of the effect of task-based language teaching on motivation and grammatical achievement of EFL junior high school students of Ahvaz. To fulfill the objectives of the study a Homogeneity test (Oxford Quick Placement Test) was administered among 100 students at the junior high school and finally 80…

  8. Gender Differences in Korean High School Students' Science Achievements and Attitudes towards Science in Three Different School Settings

    Science.gov (United States)

    Bang, EunJin; Baker, Dale R.

    2013-01-01

    This study analysed the effect of high schools' gender organization on Korean tenth-grade students' science achievements, and their attitudes towards science. The high schools involved included an all-male institution, an all-female institution, and a co-educational institution. Three schools, three principals, three science teachers, and 302…

  9. Wild Bee Community Composition and Foraging Behaviour in Commercial Strawberries

    DEFF Research Database (Denmark)

    Ahrenfeldt, Erica Juel

    -nesting polylectic solitary species that are known to forage in the family Rosaceae, to which strawberry belong, which indicate that the bees sampled are a source of pollination in strawberries (I, II). Furthermore, the high proportion of polylectic bees found in Danish strawberry fields indicate that an adaptation...

  10. Striking Differences: The Impact of Moderate and High Trauma on Reading Achievement

    Science.gov (United States)

    Duplechain, Rosalind; Reigner, Ronald; Packard, Abbot

    2008-01-01

    This study explored the relationship between childhood traumatic exposure, such as violence and loss of a significant other, and reading achievement. With a sample of 163 urban elementary children (grades 2-5), the impact of traumatic events on 3 years of reading scores was examined. Results suggested that violence exposure had an adverse effect…

  11. Young Children Selectively Expect Failure Disclosure to High-Achieving Peers

    Science.gov (United States)

    Hicks, Catherine M.; Liu, David

    2017-01-01

    Children make many decisions about whether and how to disclose their performance to peers, teachers, parents and others. Previous research has found that children's disclosure declines with age and that older children and teenagers preferentially choose a peer audience for performance disclosure based on similar achievement. This research examines…

  12. Unequal Academic Achievement in High School: The Mediating Roles of Concerted Cultivation and Close Friends

    Science.gov (United States)

    Carolan, Brian V.

    2016-01-01

    Building from the classic Wisconsin model of status attainment, this study examines whether a specific style of parenting, concerted cultivation, and a close friend's school-related attitudes and behaviors mediate the relationship between a family's socioeconomic status and their child's academic achievement in the United States. Using a recursive…

  13. When and Why Do Initially High-Achieving Poor Children Fall Behind?

    Science.gov (United States)

    Crawford, Claire; Macmillan, Lindsey; Vignoles, Anna

    2017-01-01

    In this paper, we examine the trajectories of initially higher- and lower-achieving children from lower and higher socio-economic status families from primary school through to university in England for the first time. We also explore what explains these trajectories. This enables us to provide new insights into when and why the performance of…

  14. Analysis of achievable capacity in irregularly-placed high performance mesh nodes

    CSIR Research Space (South Africa)

    Olwal, TO

    2012-09-01

    Full Text Available challenge. This paper derives the achievable capacity limit of such HPNs’ placements. The analytical results show that the network capacity increases with the irregularity of HPNs placements, the number of antennas as well as the multiplicity of radios per...

  15. Mathematically Gifted Students and High Achievement: The Role of Motivation and Classroom Structure

    Science.gov (United States)

    Lüftenegger, Marko; Kollmayer, Marlene; Bergsmann, Evelyn; Jöstl, Gregor; Spiel, Christiane; Schober, Barbara

    2015-01-01

    One of the most intriguing questions for those who study intellectually gifted students is why some of them reach peak performances at school and others don't. Moderator theories of giftedness assume that domain-specific gifts are transformed into achievement in a process influenced by non-cognitive and environmental variables. Thus, the current…

  16. Impacts of Comprehensive Reading Instruction on Diverse Outcomes of Low- and High-Achieving Readers

    Science.gov (United States)

    Guthrie, John T.; McRae, Angela; Coddington, Cassandra S.; Klauda, Susan Lutz; Wigfield, Allan; Barbosa, Pedro

    2009-01-01

    Low-achieving readers in Grade 5 often lack comprehension strategies, domain knowledge, word recognition skills, fluency, and motivation to read. Students with such multiple reading needs seem likely to benefit from instruction that supports each of these reading processes. The authors tested this expectation experimentally by comparing the…

  17. Self-Regulation, Executive Function, Working Memory, and Academic Achievement of Female High School Students

    Science.gov (United States)

    Halloran, Roberta Kathryn

    2011-01-01

    Self-regulation, executive function and working memory are areas of cognitive processing that have been studied extensively. Although many studies have examined the constructs, there is limited empirical support suggesting a formal link between the three cognitive processes and their prediction of academic achievement. Thus, the present study…

  18. The Effect of Community Linguistic Isolation on Language-Minority Student Achievement in High School

    Science.gov (United States)

    Drake, Timothy Arthur

    2014-01-01

    Research on language-minority student outcomes has revealed sizeable and persistent achievement gaps. The reasons for these gaps are often closely linked with other factors related to underperformance, including generational status, race/ethnicity, and socioeconomic status. Using sociocultural second-language acquisition theories and community…

  19. A Qualitative Study of High Student Achievement in a Rural Appalachian Region: Perceptions of Selected Superintendents

    Science.gov (United States)

    Mathis, Regina

    2011-01-01

    This qualitative study was based on grounded theory and used purposive sampling for selecting participants. The sample for this study included 12 of the 16 superintendents in this region. This rural Appalachian region has historically outperformed the remainder of the southeastern state on reading and math achievement tests at the elementary and…

  20. Faculty Sense of Academic Optimism and Its Relationship to Students' Achievement in Well Performing High Schools

    Science.gov (United States)

    Cromartie, Michael Tyrone

    2013-01-01

    The aim of this study was to determine the organizational characteristics and behaviors that contribute to sustaining a culture of academic optimism as a mechanism of student achievement. While there is a developing research base identifying both the individual elements of academic optimism as well as the academic optimism construct itself as…

  1. What's Past Is Prologue: Relations between Early Mathematics Knowledge and High School Achievement

    Science.gov (United States)

    Watts, Tyler W.; Duncan, Greg J.; Siegler, Robert S.; Davis-Kean, Pamela E.

    2014-01-01

    Although previous research has established the association between early-grade mathematics knowledge and later mathematics achievement, few studies have measured mathematical skills prior to school entry, and few have investigated the predictive power of early gains in mathematics ability. The current paper relates mathematical skills measured at…

  2. The Effect of Community Linguistic Isolation on Language-Minority Student Achievement in High School

    Science.gov (United States)

    Drake, Timothy Arthur

    2014-01-01

    Research on language-minority student outcomes has revealed sizeable and persistent achievement gaps. The reasons for these gaps are often closely linked with other factors related to underperformance, including generational status, race/ethnicity, and socioeconomic status. Using sociocultural second-language acquisition theories and community…

  3. Low-Achieving Readers, High Expectations: Image Theatre Encourages Critical Literacy

    Science.gov (United States)

    Rozansky, Carol Lloyd; Aagesen, Colleen

    2010-01-01

    Students in an eighth-grade, urban, low-achieving reading class were introduced to critical literacy through engagement in Image Theatre. Developed by liberatory dramatist Augusto Boal, Image Theatre gives participants the opportunity to examine texts in the triple role of interpreter, artist, and sculptor (i.e., image creator). The researchers…

  4. The Influence of Mathematics Anxiety in Middle and High School Students Math Achievement

    Science.gov (United States)

    Al Mutawah, Masooma Ali

    2015-01-01

    Math anxiety has been the focus of much psychological and educational research in the past few years, there are many international studies showing that mathematics anxiety is an influence on student's achievements in school, but little research has been done about this issue in Bahrain. Bahrain is a country in the Arabian Gulf region, its economic…

  5. “双链型”鲜食玉米-奶牛-沼气-龙虾-牧草循环农业模式的高效配套技术%Highly- efficient Matching Technologies for “Double- chain” Type Circulation Agriculture Model: Fresh Eatable Maize-Milk Cow-Biogas-Lobster-Forage Grass

    Institute of Scientific and Technical Information of China (English)

    张家宏; 王守红; 寇祥明; 金银根; 毕建花

    2011-01-01

    提出了“双链型”鲜食玉米-奶牛-沼气-龙虾-牧草循环农业模式的合理建设方案;集成了鲜食玉米和牧草的种植、奶牛粪及残饲的沼气化利用、克氏原螯虾养殖等高效配套技术;分析了“双链型”鲜食玉米-奶牛-沼气-龙虾-牧草循环农业模式运行的比较效益.%This article put forward a reasonable construction project of "double -chain" type circulation agriculture model: fresh eatable maize-milk cow-biogas-lobstei-forage grass, integrated the highly - efficient matching technologies of planting fresh eatable maize and forage grass, utilizing the dung and remnant forage of milk cow to produce biogas, and rearing Procambarus clarki, and analyzed the comparative effectiveness of the operation of the circulation agriculture model: fresh eatable maize-milk cow-biogas- lobster-forage grass.

  6. The evolution of foraging rate across local and geographic gradients in predation risk and competition.

    Science.gov (United States)

    Urban, Mark C; Richardson, Jonathan L

    2015-07-01

    Multiple theories predict the evolution of foraging rates in response to environmental variation in predation risk, intraspecific competition, time constraints, and temperature. We tested six hypotheses for the evolution of foraging rate in 24 spotted salamander (Ambystoma maculatum) populations from three latitudinally divergent sites using structural equation models derived from theory and applied to our system. We raised salamander larvae in a common-garden experiment and then assayed foraging rate under controlled conditions. Gape-limited predation risk from marbled salamanders solely explained foraging rate variation among populations at the southern site, which was dominated by this form of selection. However, at the middle and northern sites, populations evolved different foraging rates depending on their unique responses to local intraspecific density. The coupling of gape-limited predation risk from marbled salamanders and high intraspecific density at the middle site jointly contributed to selection for rapid foraging rate. At the northernmost site, intraspecific density alone explained 97% of the interpopulation variation in foraging rate. These results suggest that foraging rate has evolved multiple times in response to varying contributions from predation risk and intraspecific competition. Predation risk often varies along environmental gradients, and, thus, organisms might often shift evolutionary responses from minimizing predation risk to maximizing intraspecific competitive performance.

  7. The rewards of restraint in the collective regulation of foraging by harvester ant colonies.

    Science.gov (United States)

    Gordon, Deborah M

    2013-06-06

    Collective behaviour, arising from local interactions, allows groups to respond to changing conditions. Long-term studies have shown that the traits of individual mammals and birds are associated with their reproductive success, but little is known about the evolutionary ecology of collective behaviour in natural populations. An ant colony operates without central control, regulating its activity through a network of local interactions. This work shows that variation among harvester ant (Pogonomyrmex barbatus) colonies in collective response to changing conditions is related to variation in colony lifetime reproductive success in the production of offspring colonies. Desiccation costs are high for harvester ants foraging in the desert. More successful colonies tend to forage less when conditions are dry, and show relatively stable foraging activity when conditions are more humid. Restraint from foraging does not compromise a colony's long-term survival; colonies that fail to forage at all on many days survive as long, over the colony's 20-30-year lifespan, as those that forage more regularly. Sensitivity to conditions in which to reduce foraging activity may be transmissible from parent to offspring colony. These results indicate that natural selection is shaping the collective behaviour that regulates foraging activity, and that the selection pressure, related to climate, may grow stronger if the current drought in their habitat persists.

  8. Information from familiar and related conspecifics affects foraging in a solitary wolf spider.

    Science.gov (United States)

    Hoffman, Catherine R; Sitvarin, Michael I; Rypstra, Ann L

    2016-06-01

    As neighbours become familiar with one another, they can divert attention away from one another and focus on other activities. Since familiarity is a likely mechanism by which animals recognise relatives, both kinship and prior association with conspecifics should allow individuals to increase foraging. We attempted to determine if the interference observed among conspecific foragers could be mitigated by familiarity and/or kinship. Because Pardosa milvina wolf spiders are sensitive to chemotactile cues deposited on substrates by other spiders, we used cues to manipulate the information available to focal spiders. We first verified that animals could use these cues to differentiate relatives and familiar conspecifics. We then documented foraging in the presence of all combinations of related and familiar animal cues. Test spiders were slower foragers, less likely to capture prey, and consumed less of each prey item when on cues from unfamiliar kin, but were faster and more effective foragers on cues from familiar non-kin. Their reactions to familiar kin and unfamiliar non-kin were intermediate. High foraging intensity on familiar cues is consistent with the idea that animals pay less attention to neighbours after some prior association. Lower foraging effort in the presence of cues from relatives may be an attempt to reduce kin competition by shifting attention toward dispersal or to provide increased access to prey for hungry relatives nearby. These findings reveal that information from conspecifics mediates social interactions among individuals and affects foraging in ways that can influence their role in the food web.

  9. Academic buoyancy, student's achievement, and the linking role of control: A cross-lagged analysis of high school students.

    Science.gov (United States)

    Collie, Rebecca J; Martin, Andrew J; Malmberg, Lars-Erik; Hall, James; Ginns, Paul

    2015-03-01

    Previous research has indicated that although academic buoyancy and student's achievement are associated, the relationship is relatively modest. We sought to determine whether another construct might link academic buoyancy and student's achievement. Based on prior theoretical and empirical work, we examined a sense of control as one possible linking mechanism. The study analysed data from 2,971 students attending 21 Australian high schools. We conducted a cross-lagged panel design as a first means of disentangling the relative salience of academic buoyancy, control, and achievement (Phase 1). Based upon these results, we proceeded with follow-up analyses of an ordered process model linking the constructs over time (Phase 2). Findings showed that buoyancy and achievement were associated with control over time, but not with one another (Phase 1). In addition, control appeared to play a role in how buoyancy influenced achievement and that a cyclical process may operate among the three factors over time (Phase 2). The findings suggest that control may play an important role in linking past experiences of academic buoyancy and achievement to subsequent academic buoyancy and achievement. © 2015 The British Psychological Society.

  10. An agent-based model to investigate the roles of attractive and repellent pheromones in ant decision making during foraging.

    Science.gov (United States)

    Robinson, Elva J H; Ratnieks, Francis L W; Holcombe, M

    2008-11-21

    Pharaoh's ants organise their foraging system using three types of trail pheromone. All previous foraging models based on specific ant foraging systems have assumed that only a single attractive pheromone is used. Here we present an agent-based model based on trail choice at a trail bifurcation within the foraging trail network of a Pharaoh's ant colony which includes both attractive (positive) and repellent (negative) trail pheromones. Experiments have previously shown that Pharaoh's ants use both types of pheromone. We investigate how the repellent pheromone affects trail choice and foraging success in our simulated foraging system. We find that both the repellent and attractive pheromones have a role in trail choice, and that the repellent pheromone prevents random fluctuations which could otherwise lead to a positive feedback loop causing the colony to concentrate its foraging on the unrewarding trail. An emergent feature of the model is a high level of variability in the level of repellent pheromone on the unrewarding branch. This is caused by the repellent pheromone exerting negative feedback on its own deposition. We also investigate the dynamic situation where the location of the food is changed after foraging trails are established. We find that the repellent pheromone has a key role in enabling the colony to refocus the foraging effort to the new location. Our results show that having a repellent pheromone is adaptive, as it increases the robustness and flexibility of the colony's overall foraging response.

  11. Season and landscape composition affect pollen foraging distances and habitat use of honey bees.

    Science.gov (United States)

    Danner, Nadja; Molitor, Anna Maria; Schiele, Susanne; Härtel, Stephan; Steffan-Dewenter, Ingolf

    2016-09-01

    Honey bees (Apis mellifera L.) show a large variation in foraging distances and use a broad range of plant species as pollen resources, even in regions with intensive agriculture. However, it is unknown how increasing areas of mass-flowering crops like oilseed rape (Brassica napus; OSR) or a decrease of seminatural habitats (SNH) change the temporal and spatial availability of pollen resources for honey bee colonies, and thus foraging distances and frequency in different habitat types. We studied pollen foraging of honey bee colonies in 16 agricultural landscapes with independent gradients of OSR and SNH area within 2 km and used waggle dances and digital geographic maps with major land cover types to reveal the distance and visited habitat type on a landscape level. Mean pollen foraging distance of 1347 decoded bee dances was 1015 m (± 26 m; SEM). In spring, increasing area of flowering OSR within 2 km reduced mean pollen foraging distances from 1324 m to only 435 m. In summer, increasing cover of SNH areas close to the colonies (within 200 m radius) reduced mean pollen foraging distances from 846 to 469 m. Frequency of pollen foragers per habitat type, measured as the number of dances per hour and hectare, was equally high for SNH, grassland, and OSR fields, but lower for other crops and forests. In landscapes with a small proportion of SNH a significantly higher density of pollen foragers on SNH was observed, indicating that pollen resources in such simple agricultural landscapes are more limited. Overall, we conclude that SNH and mass-flowering crops can reduce foraging distances of honey bee colonies at different scales and seasons with possible benefits for the performance of honey bee colonies. Further, mixed agricultural landscapes with a high proportion of SNH reduce foraging densities of honey bees in SNH and thus possible competition for pollen resources.

  12. Dynamic oceanography determines fine scale foraging behavior of Masked Boobies in the Gulf of Mexico.

    Science.gov (United States)

    Poli, Caroline L; Harrison, Autumn-Lynn; Vallarino, Adriana; Gerard, Patrick D; Jodice, Patrick G R

    2017-01-01

    During breeding, foraging marine birds are under biological, geographic, and temporal constraints. These contraints require foraging birds to efficiently process environmental cues derived from physical habitat features that occur at nested spatial scales. Mesoscale oceanography in particular may change rapidly within and between breeding seasons, and findings from well-studied systems that relate oceanography to seabird foraging may transfer poorly to regions with substantially different oceanographic conditions. Our objective was to examine foraging behavior of a pan-tropical seabird, the Masked Booby (Sula dactylatra), in the understudied Caribbean province, a moderately productive region driven by highly dynamic currents and fronts. We tracked 135 individuals with GPS units during May 2013, November 2013, and December 2014 at a regionally important breeding colony in the southern Gulf of Mexico. We measured foraging behavior using characteristics of foraging trips and used area restricted search as a proxy for foraging events. Among individual attributes, nest stage contributed to differences in foraging behavior whereas sex did not. Birds searched for prey at nested hierarchical scales ranging from 200 m-35 km. Large-scale coastal and shelf-slope fronts shifted position between sampling periods and overlapped geographically with overall foraging locations. At small scales (at the prey patch level), the specific relationship between environmental variables and foraging behavior was highly variable among individuals but general patterns emerged. Sea surface height anomaly and velocity of water were the strongest predictors of area restricted search behavior in random forest models, a finding that is consistent with the characterization of the Gulf of Mexico as an energetic system strongly influenced by currents and eddies. Our data may be combined with tracking efforts in the Caribbean province and across tropical regions to advance understanding of seabird

  13. Paternity Testing, a Poor Man’s Marker Assisted Breeding Strategy to Increase Selection Gains in Outbred Forage Species

    Science.gov (United States)

    Many methods to incorporate molecular markers into breeding programs have been proposed. Most existing marker assisted selection strategies use selection based on molecular marker linkage to achieve selection gains. Such strategies are often prohibitively expensive in forage breeding (Riday, 2007)...

  14. Intelligence, classroom behavior, and academic achievement in children at high and low risk for psychopathology: a structural equation analysis.

    Science.gov (United States)

    Worland, J; Weeks, D G; Janes, C L; Strock, B D

    1984-09-01

    The intelligence, academic achievement, and classroom behavior of 158 children were assessed in a sample that is being followed longitudinally. The sample included children at high risk for mental disorder by virtue of having a parent with a psychiatric diagnosis of schizophrenia or affective disorder, children at moderate risk, and children at low risk. A series of path analyses indicated that in this sample (1) classroom behavior was more likely an affect that a cause of academic achievement, and (2) the influence of parental psychopathology on classroom behavior was mediated by a child's intelligence and academic achievement. We were unable to substantiate an unmediated causal link between parental psychopathology and children's academic achievement or classroom behavior.

  15. Effect of Direct Teaching Method on the Academic Achievement of High and Low Achievers in the Subject of English at the Secondary Level

    Science.gov (United States)

    Hussain, Ishtiaq; Hamdani, Syed Nisar Hussain; Quraishi, Uzma; Zeeshan, Muhammad

    2010-01-01

    The major objective of the study was to determine the role of the direct teaching method in the academic achievement of students in English at the secondary level. To achieve the said objective, the Solomon Four-Design pre-test/post-test equivalent group design was considered to be the most useful design for this study. The pre-test was used to…

  16. Developing Cyber Foraging Applications for Portable Devices

    DEFF Research Database (Denmark)

    Kristensen, Mads Darø; Bouvin, Niels Olof

    2008-01-01

    This paper presents the Locusts cyber foraging framework. Cyber foraging is the opportunistic use of computing resources available in the nearby environment, and using such resources thus fall into the category of distributed computing. Furthermore, for the resources to be used efficiently......, parallel computing techniques must also be employed. Distributed and parallel computing are two concepts that are both notoriously known for being very hard for developers to grasp. Because of this one might think that techniques such as cyber foraging would have a hard time surviving outside of research...... environments. In this paper a framework is presented that has special focus on making cyber foraging accessible for all developers....

  17. Visual Foraging With Fingers and Eye Gaze.

    Science.gov (United States)

    Jóhannesson, Ómar I; Thornton, Ian M; Smith, Irene J; Chetverikov, Andrey; Kristjánsson, Árni

    2016-03-01

    A popular model of the function of selective visual attention involves search where a single target is to be found among distractors. For many scenarios, a more realistic model involves search for multiple targets of various types, since natural tasks typically do not involve a single target. Here we present results from a novel multiple-target foraging paradigm. We compare finger foraging where observers cancel a set of predesignated targets by tapping them, to gaze foraging where observers cancel items by fixating them for 100 ms. During finger foraging, for most observers, there was a large difference between foraging based on a single feature, where observers switch easily between target types, and foraging based on a conjunction of features where observers tended to stick to one target type. The pattern was notably different during gaze foraging where these condition differences were smaller. Two conclusions follow: (a) The fact that a sizeable number of observers (in particular during gaze foraging) had little trouble switching between different target types raises challenges for many prominent theoretical accounts of visual attention and working memory. (b) While caveats must be noted for the comparison of gaze and finger foraging, the results suggest that selection mechanisms for gaze and pointing have different operational constraints.

  18. U.S. Dairy Forage Research Center

    Data.gov (United States)

    Federal Laboratory Consortium — Vision: Leading the world in integrated dairy forage systems research. Mission: Providing dairy industry solutions for food security, environmental sustainability,...

  19. U.S. DAIRY FORAGE RESEARCH CENTER

    Data.gov (United States)

    Federal Laboratory Consortium — Vision: Leading the world in integrated dairy forage systems research. Mission: Providing dairy industry solutions for food security, environmental sustainability,...

  20. Association between scores in high school, aptitude and achievement exams and early performance in health science college

    Directory of Open Access Journals (Sweden)

    Al-Alwan Ibrahim

    2009-01-01

    Full Text Available This retrospective study was carried out to assess the correlation between admi-ssion criteria to health science colleges, namely, final high school grade and Saudi National Apti-tude and Achievement exams, and early academic performance in these colleges. The study inclu-ded 91 male students studying in the two-year pre-professional program at the King Saud bin Abdulaziz University for Health Sciences (KSAU-HS, Riyadh, Saudi Arabia. Records of these students were used to extract relevant information and their academic performance (based on the grade point average achieved at the end of the first semester of the pre-professional program, which were analytically studied. Pearson correlation coefficient was used to assess the associa-tions between the different scores. SPSS statistical program (version 12.0 was used for data ana-lyses. We found a strong correlation between the academic performance and the Achievement Exam, Aptitude Exam and high school final grade, with Pearson Correlation Coefficients of 0.96, 0.93, 0.87, respectively. The Saudi National Achievement Exam showed the most significant correla-tion. Our results indicate that academic performance showed good correlation with the admission criteria used, namely final high school grade, Saudi National Aptitude and Achievement Exams.

  1. Context-dependent expression of the foraging gene in field colonies of ants: the interacting roles of age, environment and task.

    Science.gov (United States)

    Ingram, Krista K; Gordon, Deborah M; Friedman, Daniel A; Greene, Michael; Kahler, John; Peteru, Swetha

    2016-08-31

    Task allocation among social insect workers is an ideal framework for studying the molecular mechanisms underlying behavioural plasticity because workers of similar genotype adopt different behavioural phenotypes. Elegant laboratory studies have pioneered this effort, but field studies involving the genetic regulation of task allocation are rare. Here, we investigate the expression of the foraging gene in harvester ant workers from five age- and task-related groups in a natural population, and we experimentally test how exposure to light affects foraging expression in brood workers and foragers. Results from our field study show that the regulation of the foraging gene in harvester ants occurs at two time scales: levels of foraging mRNA are associated with ontogenetic changes over weeks in worker age, location and task, and there are significant daily oscillations in foraging expression in foragers. The temporal dissection of foraging expression reveals that gene expression changes in foragers occur across a scale of hours and the level of expression is predicted by activity rhythms: foragers have high levels of foraging mRNA during daylight hours when they are most active outside the nests. In the experimental study, we find complex interactions in foraging expression between task behaviour and light exposure. Oscillations occur in foragers following experimental exposure to 13 L : 11 D (LD) conditions, but not in brood workers under similar conditions. No significant differences were seen in foraging expression over time in either task in 24 h dark (DD) conditions. Interestingly, the expression of foraging in both undisturbed field and experimentally treated foragers is also significantly correlated with the expression of the circadian clock gene, cycle Our results provide evidence that the regulation of this gene is context-dependent and associated with both ontogenetic and daily behavioural plasticity in field colonies of harvester ants. Our results underscore

  2. Effect of cattle age, forage level, and corn processing on diet digestibility and feedlot performance.

    Science.gov (United States)

    Gorocica-Buenfil, M A; Loerch, S C

    2005-03-01

    Three experiments were conducted to determine the effects of cattle age and dietary forage level on the utilization of corn fed whole or ground to feedlot cattle. In Exp. 1, 16 steers were used to investigate the effects of cattle age and corn processing on diet digestibility. Two cattle age categories were evaluated (weanling [254 +/- 20 kg BW] and yearling [477 +/- 29 kg BW]; eight steers per group), and corn was fed either ground or whole to each cattle age category. Cattle age and corn processing did not affect (P > 0.10) diet digestibility of DM, OM, starch, CP, NDF or ADF, and no interactions (P > 0.10) between these two factors were detected. In Exp. 2, the effects of forage level and corn processing on feedlot performance and carcass characteristics were evaluated. One hundred eighty steers (310 +/- 40 kg BW) were allotted to 24 pens, and were fed one of the following diets: high-forage (18.2% corn silage) cracked corn (HFCC); high-forage shifting corn (whole corn for the first half of the trial, then cracked corn until harvest; HFSC); high-forage whole corn (HFWC); low-forage (5.2% corn silage) cracked corn (LFCC); low-forage shifting corn (LFSC); and low-forage whole corn (LFWC). For the high-forage diets, steers fed cracked corn had 7% greater DMI than those fed whole corn, whereas for the low-forage diets, grain processing did not affect DMI (interaction; P = 0.02). No interactions (P > 0.10) between forage level and corn processing were found for ADG and G:F. Total trial ADG and G:F, and percentage of carcasses grading USDA Choice, and carcass yield grade were not affected (P > 0.10) by corn processing. Cattle with fewer days on feed grew faster and more efficiently when cracked corn was fed, whereas cattle with longer days on feed had greater ADG and G:F when corn was fed whole (interaction; P 0.10) between forage level and corn processing were detected for starch digestibility. Forage level and corn processing (grinding) did not affect (P > 0

  3. Geographic structure of adelie penguin populations: overlap in colony-specific foraging areas

    Science.gov (United States)

    Ainley, D.G.; Ribic, C.A.; Ballard, G.; Heath, S.; Gaffney, I.; Karl, B.J.; Barton, K.J.; Wilson, P.R.; Webb, S.

    2004-01-01

    the study, when foraging trips of the large colony were very long, parents lost mass, and chick meals were smaller. In light of existing data on prey abundance in neritic waters in Antarctica suggesting that krill are relatively evenly distributed and in high abundance in the Southern Ross Sea, we conclude that penguins depleted or changed the availability of their prey, that the degree of alteration was a function of colony size, and that the large colony affected the location (and perhaps ultimately the size) of foraging areas for the smaller colonies. It appears, therefore, that foraging dynamics play a role in the geographic structuring of colonies in this species. ?? 2004 by the Ecological Society of America.

  4. Effects of habitat composition and landscape structure on worker foraging distances of five bumble bee species.

    Science.gov (United States)

    Redhead, John W; Dreier, Stephanie; Bourke, Andrew F G; Heard, Matthew S; Jordan, William C; Sumner, Seirian; Wang, Jinliang; Carvell, Claire

    2016-04-01

    Bumble bees (Bombus spp.) are important pollinators of both crops and wildflowers. Their contribution to this essential ecosystem service has been threatened over recent decades by changes in land use, which have led to declines in their populations. In order to design effective conservation measures, it is important to understand the effects of variation in landscape composition and structure on the foraging activities of worker bumble bees. This is because the viability of individual colonies is likely to be affected by the trade-off between the energetic costs of foraging over greater distances and the potential gains from access to additional resources. We used field surveys, molecular genetics, and fine resolution remote sensing to estimate the locations of wild bumble bee nests and to infer foraging distances across a 20-km² agricultural landscape in southern England, UK. We investigated five species, including the rare B. ruderatus and ecologically similar but widespread B. hortorum. We compared worker foraging distances between species and examined how variation in landscape composition and structure affected foraging distances at the colony level. Mean worker foraging distances differed significantly between species. Bombus terrestris, B. lapidarius, and B. ruderatus exhibited significantly greater mean foraging distances (551, 536, and 501 m, respectively) than B. hortorum and B. pascuorum (336 and 272 m, respectively). There was wide variation in worker foraging distances between colonies of the same species, which was in turn strongly influenced by the amount and spatial configuration of available foraging habitats. Shorter foraging distances were found for colonies where the local landscape had high coverage and low fragmentation of semi-natural vegetation, including managed agri-environmental field margins. The strength of relationships between different landscape variables and foraging distance varied between species, for example the strongest

  5. The Effect of the Flipped Classroom on Urban High School Students' Motivation and Academic Achievement in a High School Science Course

    Science.gov (United States)

    Dixon, Keshia L.

    2017-01-01

    This study investigated the effect of the flipped classroom on urban high school students' motivation and academic achievement in a high school science course. In this quantitative study, the sample population was comprised of North Star High School 12th grade students enrolled in human anatomy and physiology. A quasi-experimental,…

  6. Short Circuits or Superconductors? Effects of Group Composition on High-Achieving Students' Science Assessment Performance.

    Science.gov (United States)

    Webb, Noreen M.; Nemer, Kariane Mari; Zuniga, Stephen

    2002-01-01

    Studied the effects of group ability composition (homogeneous versus heterogeneous) on group processes and outcomes for high-ability students completing science assessments. Results for 83 high ability students show the quality of group functioning serves as the strongest predictor of high-ability students' performance and explained much of the…

  7. Inquiry-Based Laboratory Activities in Electrochemistry: High School Students' Achievements and Attitudes

    Science.gov (United States)

    Sesen, Burcin Acar; Tarhan, Leman

    2013-01-01

    This study aimed to investigate the effects of inquiry-based laboratory activities on high school students' understanding of electrochemistry and attitudes towards chemistry and laboratory work. The participants were 62 high school students (average age 17 years) in an urban public high school in Turkey. Students were assigned to experimental (N =…

  8. Status report on high temperature fuel cells in Poland – Recent advances and achievements

    DEFF Research Database (Denmark)

    Molenda, J.; Kupecki, J.; Baron, R.

    2017-01-01

    . National efforts are covering wide range of aspects both in the fundamental research and the applied research. The review present the areas of (i) novel materials for SOFC including ZrO2-based electrolytes, CeO2-based electrolytes, Bi2O3 based electrolytes and proton conducting electrolytes, (ii) cathode...... active in the field of solid oxide fuel cells (SOFC) and molten carbonate fuel cell (MCFC) is presented and discussed. The review is oriented towards presenting key achievements in the technology at the scale from microstructure up to a complete power system based on electrochemical fuel oxidation...

  9. IDENTITY AND TEMPORAL PERSPECTIVE OF ADOLESCENTS WITH HIGH ACHIEVEMENTS IN SCHOOL

    Directory of Open Access Journals (Sweden)

    Denitsa Alipieva

    2015-12-01

    Full Text Available The current article is an empirical approach reviewing the theories for the factors for formation of identity and self-conception in the adolescent. Under the theories for internal attribution and temporal perspective the study was conducted with teenagers between 11 and 18 years with different achievements. The aim is to show the relevance between the subjective affective involving and success in academic activity and realistic self-esteem that could enhance the abilities of students to create adequate plans and goals for future and mature self-conception

  10. Contrasting Foraging Patterns: Testing Resource-Concentration and Dilution Effects with Pollinators and Seed Predators

    Directory of Open Access Journals (Sweden)

    Alexandria Wenninger

    2016-06-01

    Full Text Available Resource concentration effects occur when high resource density patches attract and support more foragers than low density patches. In contrast, resource dilution effects can occur if high density patches support fewer consumers. In this study, we examined the foraging rates of pollinators and seed predators on two perennial plant species (Rudbeckia triloba and Verbena stricta as functions of resource density. Specifically, we examined whether resource-dense patches (densities of flower and seeds on individual plants resulted in greater visitation and seed removal rates, respectively. We also examined whether foraging rates were context-dependent by conducting the study in two sites that varied in resource densities. For pollinators, we found negative relationships between the density of flowers per plant and visitation rates, suggesting dilution effects. For seed predators, we found positive relationships consistent with concentration effects. Saturation effects and differences in foraging behaviors might explain the opposite relationships; most of the seed predators were ants (recruitment-based foragers, and pollinators were mostly solitary foragers. We also found that foraging rates were site-dependent, possibly due to site-level differences in resource abundance and consumer densities. These results suggest that these two plant species may benefit from producing as many flowers as possible, given high levels of pollination and low seed predation.

  11. Differences between High and Low Academic Achieving University Students in Learning and Study Strategies: A Further Investigation

    Science.gov (United States)

    Yip, Michael C. W.

    2009-01-01

    Following up on the general framework of the research study of Yip (2007), this article sets out a similar research question, investigating the differences between high and low academic achieving Hong Kong university students based on their different learning and study strategies. In this study, we recruited 100 university students who pursued…

  12. The Perceptions of Principals and Teachers Regarding Mental Health Providers' Impact on Student Achievement in High Poverty Schools

    Science.gov (United States)

    Perry, Teresa

    2012-01-01

    This study examined the perceptions of principals and teachers regarding mental health provider's impact on student achievement and behavior in high poverty schools using descriptive statistics, t-test, and two-way ANOVA. Respondents in this study shared similar views concerning principal and teacher satisfaction and levels of support for the…

  13. Self-Regulated Learning and a Sense of Achievement in MOOCs among High School Science and Technology Students

    Science.gov (United States)

    Cohen, Lizi; Magen-Nagar, Noga

    2016-01-01

    This study, conducted in Israel, examined how learning strategies and motivational orientations contributed to high school students' sense of achievement in a massive open online course. The objective was to integrate an innovative teaching-learning strategy into the educational system that is based on online learning for students in subjects that…

  14. The Effective Practices and Beliefs of School Principals in High Achieving Hispanic Majority Mid-Level Schools

    Science.gov (United States)

    Briseno, Johnny

    2010-01-01

    This qualitative phenomenological research study used narrative inquiry to investigate the effective practices and beliefs of 10 Texas principals in high achieving majority Hispanic mid-level schools. Participant interviews were analyzed using the Creswell (2007) six step method for analyzing phenomenological studies. Findings from this study…

  15. Mathematics: Self-Efficacy, Identity, and Achievement among African American Males from the High School Longitudinal Study

    Science.gov (United States)

    Briggs, Calvin

    2014-01-01

    The purpose of this study was to determine if a relationship existed between mathematics self-efficacy and mathematics identity to mathematics achievement among African American males from High School Longitudinal Study of 2009 (HSLS:09). Subsequently, the extent to which mathematics self-efficacy and mathematics identity accounted for low and…

  16. The Effect of Computer Based Instructional Technique for the Learning of Elementary Level Mathematics among High, Average and Low Achievers

    Science.gov (United States)

    Afzal, Muhammad Tanveer; Gondal, Bashir; Fatima, Nuzhat

    2014-01-01

    The major objective of the study was to elicit the effect of three instructional methods for teaching of mathematics on low, average and high achiever elementary school students. Three methods: traditional instructional method, computer assisted instruction (CAI) and teacher facilitated mathematics learning software were employed for the teaching…

  17. Exploring Differences between Self-Regulated Learning Strategies of High and Low Achievers in Open Distance Learning

    Science.gov (United States)

    Geduld, Bernadette

    2016-01-01

    Open distance students differ in their preparedness for higher education studies. Students who are less self-regulated risk failure and drop out in the challenging milieu of open distance learning. In this study, the differences between the application of self-regulated learning strategies by low and high achievers were explored. A multi-method…

  18. Effective Learning: A Case Study of the Learning Strategies Used by a Gifted High Achiever in Learning Science

    Science.gov (United States)

    Stott, Angela; Hobden, Paul A.

    2016-01-01

    This article describes a case study of a gifted high achiever in learning science. This learner was selected on the assumption that drawing attention to the characteristics of a successful learner may improve learning effectiveness of less successful learners. The first author taught the gifted learner and collected data through participant…

  19. High-School Students' Need for Cognition, Self-Control Capacity, and School Achievement: Testing a Mediation Hypothesis

    Science.gov (United States)

    Bertrams, Alex; Dickhauser, Oliver

    2009-01-01

    In the present article, we examine the hypothesis that high-school students' motivation to engage in cognitive endeavors (i.e., their need for cognition; NFC) is positively related to their dispositional self-control capacity. Furthermore, we test the prediction that the relation between NFC and school achievement is mediated by self-control…

  20. Relationships of Cognitive and Metacognitive Learning Strategies to Mathematics Achievement in Four High-Performing East Asian Education Systems

    Science.gov (United States)

    Areepattamannil, Shaljan; Caleon, Imelda S.

    2013-01-01

    The authors examined the relationships of cognitive (i.e., memorization and elaboration) and metacognitive learning strategies (i.e., control strategies) to mathematics achievement among 15-year-old students in 4 high-performing East Asian education systems: Shanghai-China, Hong Kong-China, Korea, and Singapore. In all 4 East Asian education…

  1. Practice Brief: Assessing Compensatory Strategies and Motivational Factors in High-Achieving Postsecondary Students with Attention Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Schaffer, Gary

    2013-01-01

    Research speculates that high-achieving college students with attention deficit/hyperactivity disorder (ADHD) may demonstrate a set of compensatory strategies and experience areas of difficulty and motivational factors that differ from the general ADHD populace. This Practice Brief used informal surveys with seven undergraduates with ADHD who had…

  2. The Effect of Poverty on the Achievement of Urban African American Male Students Successfully Completing High School

    Science.gov (United States)

    Welch, Amy L.

    2013-01-01

    The purpose of this study was to determine the impact of poverty on the achievement of African American male high school students attending the same large Midwest urban school district. Cumulative grade point average (GPA) at the tenth grade level were compared to the level of poverty provided through census data of African American male tenth…

  3. The Effects of Individual or Group Guidelines on the Calibration Accuracy and Achievement of High School Biology Students

    Science.gov (United States)

    Bol, Linda; Hacker, Douglas J.; Walck, Camilla C.; Nunnery, John A.

    2012-01-01

    A 2 x 2 factorial design was employed in a quasi-experiment to investigate the effects of guidelines in group or individual settings on the calibration accuracy and achievement of 82 high school biology students. Significant main effects indicated that calibration practice with guidelines and practice in group settings increased prediction and…

  4. High-Achieving Black Students, Biculturalism, and Out-of-School STEM Learning Experiences: Exploring Some Unintended Consequences

    Science.gov (United States)

    McGee, Ebony O.

    2013-01-01

    In this article, the author discusses the complex challenges of high-achieving Black students who are successful in becoming immersed in predominately White STEM (science, technology, engineering, and mathematics) spaces and how such immersion can exacerbate their experiences of racial stereotyping and other forms of racial bias. The author…

  5. The Effect of Consistent Structured Reading Instruction on High and Low Literacy Achievement in Young Children Who Are Blind

    Science.gov (United States)

    Emerson, Robert Wall; Sitar, Debbie; Erin, Jane N.; Wormsley, Diane P.; Herlich, Stephanie Leigh

    2009-01-01

    The Alphabetic Braille and Contracted Braille Study found no difference between high and low achievers in the development of literacy skills on such measures as age, etiology of visual impairment, family attitudes and behaviors regarding literacy activities, class size, and time spent with a teacher of students with visual impairments. Some…

  6. Differences in Learning and Study Strategies between High and Low Achieving University Students: A Hong Kong Study

    Science.gov (United States)

    Yip, Michael C. W.

    2007-01-01

    This study aims to investigate the differences between high and low academic achieving Hong Kong University students in terms of learning and study strategies. A total of 180 Hong Kong University students participated in the present study by completing a revised Chinese version of the Learning and Study Strategies Inventory. Results indicated that…

  7. Differences between High and Low Academic Achieving University Students in Learning and Study Strategies: A Further Investigation

    Science.gov (United States)

    Yip, Michael C. W.

    2009-01-01

    Following up on the general framework of the research study of Yip (2007), this article sets out a similar research question, investigating the differences between high and low academic achieving Hong Kong university students based on their different learning and study strategies. In this study, we recruited 100 university students who pursued…

  8. Android worksheet application based on discovery learning on students' achievement for vocational high school: Mechanical behavior of materials topics

    Science.gov (United States)

    Nanto, Dwi; Aini, Anisa Nurul; Mulhayatiah, Diah

    2017-05-01

    This research reports a study of student worksheet based on discovery learning on Mechanical Behavior of Materials topics under Android application (Android worksheet application) for vocational high school. The samples are Architecture class X students of SMKN 4 (a public vocational high school) in Tangerang Selatan City, province of Banten, Indonesia. We made 3 groups based on Intellectual Quotient (IQ). They are average IQ group, middle IQ group and high IQ group. The method of research is used as a quasi-experimental design with nonequivalent control group design. The technique of sampling is purposive sampling. Instruments used in this research are test instruments and non-test instruments. The test instruments are IQ test and test of student's achievement. For the test of student's achievement (pretest and posttest) we provide 25 multiple choice problems. The non-test instruments are questionnaire responses by the students and the teacher. Without IQ categorized, the result showed that there is an effect of Android worksheet application on student's achievement based on cognitive aspects of Revised Bloom's Taxonomy. However, from the IQ groups point of view, only the middle IQ group and the high IQ group showed a significant effect from the Android worksheet application on student's achievement meanwhile for the average IQ group there was no effect.

  9. Interactions between shoal size and conformity in guppy social foraging

    NARCIS (Netherlands)

    Day, R.L.; Macdonald, T.; Brown, C.; Laland, K.N.; Reader, S.M.

    2001-01-01

    Previous experimental studies have established that shoaling fish forage more effectively in large than small groups. We investigated how shoal size affects the foraging efficiency of laboratory populations of the guppy, Poecilia reticulata, exposed to different foraging tasks. Experiment 1

  10. High school students' science academic achievement: The effect of the Lemov positive framing trust-building technique

    Science.gov (United States)

    Gigliette, Linda Marie

    The purpose of this research was to investigate the effect of a trust-building technique called "positive-framing" (Lemov, 2010, p. 204) on the level of student-teacher trust and students' science academic achievement. The existing literature was reviewed under the constructs of trust, types of trust, trust-building strategies, and student academic achievement. The identified problem is a lack of research into the effect of trust from the high school student perspective and the effect of trust on student academic achievement in science. In addition, there is no empirical evidence to support the effectiveness of the "positive-framing" (Lemov, 2010, p. 204) trust-building intervention. The study involved a volunteer, convenience sample of 9th-grade science students at one high school in Northern California (N=240). The study employed a quasi-experimental, pretest, posttest non-equivalent control group design to examine the level of student trust in the teacher, using the "Student trust in faculty scale" (Forsyth, Adams, & Hoy, 2011, p. 180), and the students' academic achievement, according to the Integrated Process Skills Test II (Okey, Wise, & Burns, 1982). The independent variable was the "positive-framing" (Lemov, 2010, p. 204) trust-building intervention; the two dependent variables were the level of student-teacher trust and student academic achievement. The composite data from the "Student trust in faculty scale" and the academic achievement test were evaluated by a multivariate analysis of covariance (MANCOVA). Results of this study indicated that the null hypothesis was accepted. The "positive-framing" (Lemov, 2010, p. 204) trust-building intervention did not have a significant effect on either the student-teacher trust level or academic achievement in science.

  11. Combining enhanced biomass density with reduced lignin level for improved forage quality.

    Science.gov (United States)

    Gallego-Giraldo, Lina; Shadle, Gail; Shen, Hui; Barros-Rios, Jaime; Fresquet Corrales, Sandra; Wang, Huanzhong; Dixon, Richard A

    2016-03-01

    To generate a forage crop with increased biomass density that retains forage quality, we have genetically transformed lines of alfalfa (Medicago sativa L.) expressing antisense constructs targeting two different lignin pathway biosynthetic genes with a construct for down-regulation of a WRKY family transcription factor that acts as a repressor of secondary cell wall formation in pith tissues. Plants with low-level expression of the WRKY dominant repressor construct produced lignified cell walls in pith tissues and exhibited enhanced biomass and biomass density, with an increase in total sugars in the cell wall fraction; however, lines with high expression of the WRKY dominant repressor construct exhibited a very different phenotype, with loss of interfascicular fibres associated with repression of the NST1 transcription factor. This latter phenotype was not observed in transgenic lines in which the WRKY transcription factor was down-regulated by RNA interference. Enhanced and/or ectopic deposition of secondary cell walls was also seen in corn and switchgrass expressing WRKY dominant repressor constructs, with enhanced biomass in corn but reduced biomass in switchgrass. Neutral detergent fibre digestibility was not impacted by WRKY expression in corn. Cell walls from WRKY-DR-expressing alfalfa plants with enhanced secondary cell wall formation exhibited increased sugar release efficiency, and WRKY dominant repressor expression further increased sugar release in alfalfa down-regulated in the COMT, but not the HCT, genes of lignin biosynthesis. These results suggest that significant enhancements in forage biomass and quality can be achieved through engineering WRKY transcription factors in both monocots and dicots. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  12. Importance and condition of forage crops seed production in agriculture of the Republic of Serbia

    Directory of Open Access Journals (Sweden)

    Đokić Dragoslav

    2013-01-01

    Full Text Available For contemporary and economical livestock production, especially cattle and sheep raising, it is necessary to achieve high production of livestock feed while reducing production costs. Improving the production of perennial grasses and legumes creates a good basis for the development of livestock production in different agro-ecological conditions of Serbia. It also establishes a link between farming and animal husbandry, which is of particular importance for the preservation and higher fertility of arable land and the protection of agro-ecosystems. An important factor for the cheaper production of livestock feed is the possibility to provide sufficient quantities of quality seeds at affordable prices. Production of quality seeds of local varieties of perennial legumes is possible to obtain sufficient amounts of good quality forage. Current situation in forage crop seed production of the Republic of Serbia is unsatisfactory because the seed of perennial grasses are mostly imported. Domestic production of alfalfa, red clover and birdsfoot trefoil met domestic needs only in some years. Seed of imported varieties are often not satisfactory because those varieties are not adapted to our local agro-ecological conditions. The present results provide the basis and direction for further researches that may provide solutions to increase seed yields and which will be widely accepted in practice, which will make the production more cost-effective. Institute for forage crops Kruševac is making a significant contribution to the development of technology of seed productions, especially alfalfa, red clover and perennial grasses. Therefore the role of the Institute is very important and necessary link between production, processing and trading seeds of perennial legumes and grasses in Serbia.

  13. Following a foraging fish-finder: diel habitat use of Blainville's beaked whales revealed by echolocation.

    Directory of Open Access Journals (Sweden)

    Patricia Arranz

    Full Text Available Simultaneous high resolution sampling of predator behavior and habitat characteristics is often difficult to achieve despite its importance in understanding the foraging decisions and habitat use of predators. Here we tap into the biosonar system of Blainville's beaked whales, Mesoplodon densirostris, using sound and orientation recording tags to uncover prey-finding cues available to echolocating predators in the deep-sea. Echolocation sounds indicate where whales search and encounter prey, as well as the altitude of whales above the sea-floor and the density of organisms around them, providing a link between foraging activity and the bio-physical environment. Tagged whales (n = 9 hunted exclusively at depth, investing most of their search time either in the lower part of the deep scattering layer (DSL or near the sea-floor with little diel change. At least 43% (420/974 of recorded prey-capture attempts were performed within the benthic boundary layer despite a wide range of dive depths, and many dives included both meso- and bentho-pelagic foraging. Blainville's beaked whales only initiate searching when already deep in the descent and encounter prey suitable for capture within 2 min of the start of echolocation, suggesting that these whales are accessing prey in reliable vertical strata. Moreover, these prey resources are sufficiently dense to feed the animals in what is effectively four hours of hunting per day enabling a strategy in which long dives to exploit numerous deep-prey with low nutritional value require protracted recovery periods (average 1.5 h between dives. This apparent searching efficiency maybe aided by inhabiting steep undersea slopes with access to both the DSL and the sea-floor over small spatial scales. Aggregations of prey in these biotopes are located using biosonar-derived landmarks and represent stable and abundant resources for Blainville's beaked whales in the otherwise food-limited deep-ocean.

  14. Following a foraging fish-finder: diel habitat use of Blainville's beaked whales revealed by echolocation.

    Science.gov (United States)

    Arranz, Patricia; Aguilar de Soto, Natacha; Madsen, Peter T; Brito, Alberto; Bordes, Fernando; Johnson, Mark P

    2011-01-01

    Simultaneous high resolution sampling of predator behavior and habitat characteristics is often difficult to achieve despite its importance in understanding the foraging decisions and habitat use of predators. Here we tap into the biosonar system of Blainville's beaked whales, Mesoplodon densirostris, using sound and orientation recording tags to uncover prey-finding cues available to echolocating predators in the deep-sea. Echolocation sounds indicate where whales search and encounter prey, as well as the altitude of whales above the sea-floor and the density of organisms around them, providing a link between foraging activity and the bio-physical environment. Tagged whales (n = 9) hunted exclusively at depth, investing most of their search time either in the lower part of the deep scattering layer (DSL) or near the sea-floor with little diel change. At least 43% (420/974) of recorded prey-capture attempts were performed within the benthic boundary layer despite a wide range of dive depths, and many dives included both meso- and bentho-pelagic foraging. Blainville's beaked whales only initiate searching when already deep in the descent and encounter prey suitable for capture within 2 min of the start of echolocation, suggesting that these whales are accessing prey in reliable vertical strata. Moreover, these prey resources are sufficiently dense to feed the animals in what is effectively four hours of hunting per day enabling a strategy in which long dives to exploit numerous deep-prey with low nutritional value require protracted recovery periods (average 1.5 h) between dives. This apparent searching efficiency maybe aided by inhabiting steep undersea slopes with access to both the DSL and the sea-floor over small spatial scales. Aggregations of prey in these biotopes are located using biosonar-derived landmarks and represent stable and abundant resources for Blainville's beaked whales in the otherwise food-limited deep-ocean.

  15. A comprehensive approach to decipher biological computation to achieve next generation high-performance exascale computing.

    Energy Technology Data Exchange (ETDEWEB)

    James, Conrad D.; Schiess, Adrian B.; Howell, Jamie; Baca, Michael J.; Partridge, L. Donald; Finnegan, Patrick Sean; Wolfley, Steven L.; Dagel, Daryl James; Spahn, Olga Blum; Harper, Jason C.; Pohl, Kenneth Roy; Mickel, Patrick R.; Lohn, Andrew; Marinella, Matthew

    2013-10-01

    The human brain (volume=1200cm3) consumes 20W and is capable of performing > 10^16 operations/s. Current supercomputer technology has reached 1015 operations/s, yet it requires 1500m^3 and 3MW, giving the brain a 10^12 advantage in operations/s/W/cm^3. Thus, to reach exascale computation, two achievements are required: 1) improved understanding of computation in biological tissue, and 2) a paradigm shift towards neuromorphic computing where hardware circuits mimic properties of neural tissue. To address 1), we will interrogate corticostriatal networks in mouse brain tissue slices, specifically with regard to their frequency filtering capabilities as a function of input stimulus. To address 2), we will instantiate biological computing characteristics such as multi-bit storage into hardware devices with future computational and memory applications. Resistive memory devices will be modeled, designed, and fabricated in the MESA facility in consultation with our internal and external collaborators.

  16. The Effects of Two Scheduling Formats on Student Achievement in a Suburban High School Setting

    Science.gov (United States)

    Jackson, Kenyada Morton

    2013-01-01

    Limited studies have been conducted on the relationship between scheduling formats and academic performance of high school students. At the target high school, students underperform on standardized tests in English language arts (ELA) and math. The purpose of this causal comparative quantitative study was to compare the means of ELA and math test…

  17. Teachers' Awareness of Cultural Diversity and Academic Achievement in Ninth Grade Academies and Senior High Schools

    Science.gov (United States)

    Whipps-Johnson, Jamellah Renee

    2016-01-01

    High school graduation rates are higher than they have ever been in 40 years, but disparities continue to exist for students of color and students from poverty when compared to their counterparts. High school reform efforts like creating small learning communities are promising, but small schools alone do not improve student outcomes.…

  18. Teachers' Awareness of Cultural Diversity and Academic Achievement in Ninth Grade Academies and Senior High Schools

    Science.gov (United States)

    Whipps-Johnson, Jamellah Renee

    2016-01-01

    High school graduation rates are higher than they have ever been in 40 years, but disparities continue to exist for students of color and students from poverty when compared to their counterparts. High school reform efforts like creating small learning communities are promising, but small schools alone do not improve student outcomes.…

  19. The Relationships among Reported Strategy Use, Metacognitive Awareness, and Reading Achievement of High School Students

    Science.gov (United States)

    Hong-Nam, Kay; Leavell, Alexandra G.; Maher, Sheila

    2014-01-01

    The metacognitive awareness and reading strategy use of high school students enrolled in two high schools were investigated. The correlations between reading scores and strategy use were examined as well as the variation in strategy use by self-rated reading proficiency and academic grades. The factor analysis revealed four factors on the…

  20. Effective Leadership Practices of Catholic High School Principals That Support Student Achievement

    Science.gov (United States)

    Valadez, Denise

    2013-01-01

    The purpose of this study was to determine what effective leadership practices are employed by Catholic high school principals to cultivate a culture of academic success and foster Catholic identity. This study addressed and identified the following: 1) the effective leadership skills Catholic high school principals need to embody to be successful…

  1. Inspiring science achievement: a mixed methods examination of the practices and characteristics of successful science programs in diverse high schools

    Science.gov (United States)

    Scogin, Stephen C.; Cavlazoglu, Baki; LeBlanc, Jennifer; Stuessy, Carol L.

    2017-08-01

    While the achievement gap in science exists in the US, research associated with our investigation reveals some high school science programs serving diverse student bodies are successfully closing the gap. Using a mixed methods approach, we identified and investigated ten high schools in a large Southwestern state that fit the definition of "highly successful, highly diverse". By conducting interviews with science liaisons associated with each school and reviewing the literature, we developed a rubric identifying specific characteristics associated with successful science programs. These characteristics and practices included setting high expectations for students, providing extensive teacher support for student learning, and utilizing student-centered pedagogy. We used the rubric to assess the successful high school science programs and compare them to other high school science programs in the state (i.e., less successful and less diverse high school science programs). Highly successful, highly diverse schools were very different in their approach to science education when compared to the other programs. The findings from this study will help schools with diverse students to strengthen hiring practices, enhance teacher support mechanisms, and develop student-focused strategies in the classroom that increase science achievement.

  2. Predator personality and prey behavioural predictability jointly determine foraging performance

    Science.gov (United States)

    Chang, Chia-chen; Teo, Huey Yee; Norma-Rashid, Y.; Li, Daiqin

    2017-01-01

    Predator-prey interactions play important roles in ecological communities. Personality, consistent inter-individual differences in behaviour, of predators, prey or both are known to influence inter-specific interactions. An individual may also behave differently under the same situation and the level of such variability may differ between individuals. Such intra-individual variability (IIV) or predictability may be a trait on which selection can also act. A few studies have revealed the joint effect of personality types of both predators and prey on predator foraging performance. However, how personality type and IIV of both predators and prey jointly influence predator foraging performance remains untested empirically. Here, we addressed this using a specialized spider-eating jumping spider, Portia labiata (Salticidae), as the predator, and a jumping spider, Cosmophasis umbratica, as the prey. We examined personality types and IIVs of both P. labiata and C. umbratica and used their inter- and intra-individual behavioural variation as predictors of foraging performance (i.e., number of attempts to capture prey). Personality type and predictability had a joint effect on predator foraging performance. Aggressive predators performed better in capturing unpredictable (high IIV) prey than predictable (low IIV) prey, while docile predators demonstrated better performance when encountering predictable prey. This study highlights the importance of the joint effect of both predator and prey personality types and IIVs on predator-prey interactions. PMID:28094288

  3. Scrounging by foragers can resolve the paradox of enrichment.

    Science.gov (United States)

    Toyokawa, Wataru

    2017-03-01

    Theoretical models of predator-prey systems predict that sufficient enrichment of prey can generate large amplitude limit cycles, paradoxically causing a high risk of extinction (the paradox of enrichment). Although real ecological communities contain many gregarious species, whose foraging behaviour should be influenced by socially transmitted information, few theoretical studies have examined the possibility that social foraging might resolve this paradox. I considered a predator population in which individuals play the producer-scrounger foraging game in one-prey-one-predator and two-prey-one-predator systems. I analysed the stability of a coexisting equilibrium point in the one-prey system and that of non-equilibrium dynamics in the two-prey system. The results revealed that social foraging could stabilize both systems, and thereby resolve the paradox of enrichment when scrounging behaviour (i.e. kleptoparasitism) is prevalent in predators. This suggests a previously neglected mechanism underlying a powerful effect of group-living animals on the sustainability of ecological communities.

  4. Effects of Visible and Invisible Hyperlinks on Vocabulary Acquisition and Reading Comprehension for High- and Average-Foreign Language Achievers

    Directory of Open Access Journals (Sweden)

    Ofelia R. Nikolova

    2004-12-01

    Full Text Available This study investigated the effects of visible and invisible links for annotated words in a computer module for learning French on the vocabulary acquisition and reading comprehension of two types of students – high – and average-achievers. Two hundred and sixty four second-semester students of French were identified as high- or average-achievers. Each type of students was then randomly assigned to two groups – with visible or invisible hyperlinks. All students were instructed to read a short passage in French (181 words for general comprehension and allowed to consult the annotated words (made visible by bold face for the visible links group as much as they needed. The students took a vocabulary pretest and an immediate and delayed (two weeks vocabulary and reading comprehension posttest. The results of the study showed that average- achievers benefited more from the visible links for vocabulary acquisition and reading comprehension than high-achievers. The results are discussed in light of second language acquisition and gifted-student theories and suggestions for future research are made.

  5. Environmental conditions and intraspecific interference: unexpected effects of turbidity on pike (Esox lucius) foraging

    DEFF Research Database (Denmark)

    Nilsson, P.A.; Jacobsen, Lene; Berg, Søren;

    2009-01-01

    on pike foraging alone or among conspecifics in different levels of water turbidity, we expected high turbidity to decrease the perceived risk of intraspecific interactions among pike, and thereby decrease the strength of interference, as turbidity would decrease the visual contact between individuals...... and act as a refuge from behavioural interactions. The results show that this is not the case, but suggest that interference is induced instead of reduced in high turbidity. Per capita foraging rates do not differ between pike foraging alone or in groups in our clear and moderately turbid treatments......, indicating no effect of interference. As high turbidity enhances prey consumption for pike individuals foraging alone, but does not have this effect for pike in groups, high turbidity induces the relative interference effect. We suggest that future evaluations of the stabilizing effects of interference...

  6. High-Speed Non-Volatile Optical Memory: Achievements and Challenges

    Directory of Open Access Journals (Sweden)

    Vadym Zayets

    2017-01-01

    Full Text Available We have proposed, fabricated, and studied a new design of a high-speed optical non-volatile memory. The recoding mechanism of the proposed memory utilizes a magnetization reversal of a nanomagnet by a spin-polarized photocurrent. It was shown experimentally that the operational speed of this memory may be extremely fast above 1 TBit/s. The challenges to realize both a high-speed recording and a high-speed reading are discussed. The memory is compact, integratable, and compatible with present semiconductor technology. If realized, it will advance data processing and computing technology towards a faster operation speed.

  7. Reduced foraging investment as an adaptation to patchy food sources: A phasic army ant simulation.

    Science.gov (United States)

    Teseo, Serafino; Delloro, Francesco

    2017-09-07

    Colonies of several ant species within the subfamily Dorylinae alternate stereotypical discrete phases of foraging and reproduction. Such phasic cycles are thought to be adaptive because they minimize the amount of foraging and the related costs, and at the same time enhance the colony-level ability to rely on patchily distributed food sources. In order to investigate these hypotheses, we use here a simple computational approach to study the population dynamics of two species of virtual ant colonies that differ quantitatively in their foraging investment. One species, which we refer to as "phasic", forages only half of the time, mirroring the phasic activity of some army ants; the other "non-phasic" species forages instead all the time. We show that, when foraging costs are relatively high, populations of phasic colonies grow on average faster than non-phasic populations, outcompeting them in mixed populations. Interestingly, such tendency becomes more consistent as food becomes more difficult to find but locally abundant. According to our results, reducing the foraging investment, for example by adopting a phasic lifestyle, can result in a reproductive advantage, but only in specific conditions. We thus suggest phasic colony cycles to have emerged together with the doryline specialization in feeding on the brood of other eusocial insects, a resource that is hard to obtain but highly abundant if available. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Foraging behaviour by parasitoids in multiherbivore communities

    NARCIS (Netherlands)

    Rijk, de M.; Dicke, M.; Poelman, E.H.

    2013-01-01

    Parasitoid foraging decisions are often affected by community characteristics such as community diversity and complexity. As part of a complex habitat, the presence of unsuitable hosts may affect foraging behaviour of parasitoids. First, unsuitable herbivores may affect the localization of patches w

  9. Increased carrying capacity with perennial forage kochia

    Science.gov (United States)

    Carrying capacity can be increased on grass-dominated rangeland pastures by including perennial forage kochia (Kochia prostrata) as one of the plant components. The objectives of the study reported here were to compare the differences of traditional winter pastures versus pastures with forage kochi...

  10. Optimal forager against ideal free distributed prey.

    Science.gov (United States)

    Garay, József; Cressman, Ross; Xu, Fei; Varga, Zoltan; Cabello, Tomás

    2015-07-01

    The introduced dispersal-foraging game is a combination of prey habitat selection between two patch types and optimal-foraging approaches. Prey's patch preference and forager behavior determine the prey's survival rate. The forager's energy gain depends on local prey density in both types of exhaustible patches and on leaving time. We introduce two game-solution concepts. The static solution combines the ideal free distribution of the prey with optimal-foraging theory. The dynamical solution is given by a game dynamics describing the behavioral changes of prey and forager. We show (1) that each stable equilibrium dynamical solution is always a static solution, but not conversely; (2) that at an equilibrium dynamical solution, the forager can stabilize prey mixed patch use strategy in cases where ideal free distribution theory predicts that prey will use only one patch type; and (3) that when the equilibrium dynamical solution is unstable at fixed prey density, stable behavior cycles occur where neither forager nor prey keep a fixed behavior.

  11. Utilization of a Buffered Dielectric to Achieve High Field-Effect Carrier Mobility in Graphene Transistors

    OpenAIRE

    Farmer, Damon B.; Chiu, Hsin-Ying; Lin, Yu-Ming; Jenkins, Keith A.; Xia, Fengnian; Avouris, Phaedon

    2009-01-01

    We utilize an organic polymer buffer layer between graphene and conventional gate dielectrics in top-gated graphene transistors. Unlike other insulators, this dielectric stack does not significantly degrade carrier mobility, allowing for high field-effect mobilities to be retained in top-gate operation. This is demonstrated in both two-point and four-point analysis, and in the high-frequency operation of a graphene transistor. Temperature dependence of the carrier mobility suggests that phono...

  12. Advanced phenotyping offers opportunities for improved breeding of forage and turf species

    DEFF Research Database (Denmark)

    Walter, Achim; Studer, Bruno; Kölliker, Roland

    2012-01-01

    Background and Aims Advanced phenotyping, i.e. the application of automated, high-throughput methods to characterize plant architecture and performance, has the potential to accelerate breeding progress but is far from being routinely used in current breeding approaches. In forage and turf...... improvement programmes, in particular, where breeding populations and cultivars are characterized by high genetic diversity and substantial genotype × environment interactions, precise and efficient phenotyping is essential to meet future challenges imposed by climate change, growing demand and declining...... resources. Scope This review highlights recent achievements in the establishment of phenotyping tools and platforms. Some of these tools have originally been established in remote sensing, some in precision agriculture, while others are laboratory-based imaging procedures. They quantify plant colour...

  13. Achieving a 100% Renewable Grid: Operating Electric Power Systems with Extremely High Levels of Variable Renewable Energy

    Energy Technology Data Exchange (ETDEWEB)

    Kroposki, Benjamin; Johnson, Brian; Zhang, Yingchen; Gevorgian, Vahan; Denholm, Paul; Hodge, Bri-Mathias; Hannegan, Bryan

    2017-03-01

    What does it mean to achieve a 100% renewable grid? Several countries already meet or come close to achieving this goal. Iceland, for example, supplies 100% of its electricity needs with either geothermal or hydropower. Other countries that have electric grids with high fractions of renewables based on hydropower include Norway (97%), Costa Rica (93%), Brazil (76%), and Canada (62%). Hydropower plants have been used for decades to create a relatively inexpensive, renewable form of energy, but these systems are limited by natural rainfall and geographic topology. Around the world, most good sites for large hydropower resources have already been developed. So how do other areas achieve 100% renewable grids? Variable renewable energy (VRE), such as wind and solar photovoltaic (PV) systems, will be a major contributor, and with the reduction in costs for these technologies during the last five years, large-scale deployments are happening around the world.

  14. Donde Estan los Estudiantes Puertorriquenos/os Exitosos? [Where Are the Academically Successful Puerto Rican Students?]: Success Factors of High-Achieving Puerto Rican High School Students

    Science.gov (United States)

    Antrop-Gonzalez, Rene; Velez, William; Garrett, Tomas

    2005-01-01

    This article describes the 4 success factors that 10 working class Puerto Rican urban high school students attributed to their high academic achievement. These success factors were (a) the acquisition of social capital through religiosity and participation in school and community-based extracurricular activities, (b) having a strong Puerto Rican…

  15. Time-resolved photoemission apparatus achieving sub-20-meV energy resolution and high stability

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Y., E-mail: ishiday@issp.u-tokyo.ac.jp [ISSP, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581 (Japan); RIKEN SPring-8 Center, Sayo, Sayo, Hyogo 679-5148 (Japan); Togashi, T.; Yamamoto, K. [RIKEN SPring-8 Center, Sayo, Sayo, Hyogo 679-5148 (Japan); Tanaka, M.; Kiss, T.; Otsu, T. [ISSP, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581 (Japan); Kobayashi, Y. [ISSP, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581 (Japan); CREST, Japan Science and Technology Agency, Tokyo 102-0075 (Japan); Shin, S. [ISSP, University of Tokyo, Kashiwa-no-ha, Kashiwa, Chiba 277-8581 (Japan); RIKEN SPring-8 Center, Sayo, Sayo, Hyogo 679-5148 (Japan); CREST, Japan Science and Technology Agency, Tokyo 102-0075 (Japan)

    2014-12-15

    The paper describes a time- and angle-resolved photoemission apparatus consisting of a hemispherical analyzer and a pulsed laser source. We demonstrate 1.48-eV pump and 5.92-eV probe measurements at the ⩾10.5-meV and ⩾240-fs resolutions by use of fairly monochromatic 170-fs pulses delivered from a regeneratively amplified Ti:sapphire laser system operating typically at 250 kHz. The apparatus is capable to resolve the optically filled superconducting peak in the unoccupied states of a cuprate superconductor, Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+δ}. A dataset recorded on Bi(111) surface is also presented. Technical descriptions include the followings: A simple procedure to fine-tune the spatio-temporal overlap of the pump-and-probe beams and their diameters; achieving a long-term stability of the system that enables a normalization-free dataset acquisition; changing the repetition rate by utilizing acoustic optical modulator and frequency-division circuit.

  16. Inclusion in High - Achieving Singapore: Challenges of Building an Inclusive Society in Policy and Practice

    Directory of Open Access Journals (Sweden)

    Zachary Walker

    2016-09-01

    Full Text Available Building an inclusive society in which all people can participate effectively and live together requires understanding inclusive education and its impact on the social order. As countries of different regions face the vast array of challenges unique to their educational systems, it becomes apparent that inclusive societies are intricately tied to social inclusion policy initiatives and developments in education. Governments are becoming increasingly aware of the need to review their educational systems as they attempt to define what an inclusive society is and how to make inclusion truly effective. Singapore is a unique example of a country that has the resources and the vision, but currently lacks an educational system designed to fully include individuals with special needs. Although Singaporean students consistently score near the top in science, math, and reading achievement on international assessments, many students with special needs still receive their education in schools separated from their mainstream peers. In 2004, Prime Minister Lee Hsien Loong discussed a new vision of Singapore becoming an inclusive society that embraces all individuals with special learning needs. In this manuscript, the authors provide a brief history of Singapore and its education system and explore how PM Lee’s vision of an inclusive society has shaped practice and policy in Singapore schools in the last decade. Specific ideas and next steps for creating an inclusive Singapore for individuals with disabilities are discussed.

  17. Universality classes of foraging with resource renewal

    Science.gov (United States)

    Chupeau, M.; Bénichou, O.; Redner, S.

    2016-03-01

    We determine the impact of resource renewal on the lifetime of a forager that depletes its environment and starves if it wanders too long without eating. In the framework of a minimal starving random-walk model with resource renewal, there are three universal classes of behavior as a function of the renewal time. For sufficiently rapid renewal, foragers are immortal, while foragers have a finite lifetime otherwise. In the specific case of one dimension, there is a third regime, for sufficiently slow renewal, in which the lifetime of the forager is independent of the renewal time. We outline an enumeration method to determine the mean lifetime of the forager in the mortal regime.

  18. Foraging in groups affects giving-up densities: solo foragers quit sooner.

    Science.gov (United States)

    Carthey, Alexandra J R; Banks, Peter B

    2015-07-01

    The giving-up density framework is an elegant and widely adopted mathematical approach to measuring animals' foraging decisions at non-replenishing artificial resource patches. Under this framework, an animal should "give up" when the benefits of foraging are outweighed by the costs (e.g., predation risk, energetic, and/or missed opportunity costs). However, animals of many species may forage in groups, and group size is expected to alter perceived predation risk and hence influence quitting decisions. Yet, most giving-up density studies assume either that individuals forage alone or that giving-up densities are not affected by group foraging. For animals that forage both alone and in groups, differences in giving-up densities due to group foraging rather than experimental variables may substantially alter interpretation. However, no research to date has directly investigated how group foraging affects the giving-up density. We used remote-sensing cameras to identify instances of group foraging in two species of Rattus across three giving-up density experiments to determine whether group foraging influences giving-up densities. Both Rattus species have been observed to vary between foraging alone and in groups. In all three experiments, solo foragers left higher giving-up densities on average than did group foragers. This result has important implications for studies using giving-up densities to investigate perceived risk, the energetic costs of searching, handling time, digestion, and missed opportunity costs, particularly if groups of animals are more likely to experience certain experimental treatments. It is critically important that future giving-up density studies consider the effects of group foraging.

  19. Achieving a long-lived high-beta plasma state by energetic beam injection.

    Science.gov (United States)

    Guo, H Y; Binderbauer, M W; Tajima, T; Milroy, R D; Steinhauer, L C; Yang, X; Garate, E G; Gota, H; Korepanov, S; Necas, A; Roche, T; Smirnov, A; Trask, E

    2015-04-23

    Developing a stable plasma state with high-beta (ratio of plasma to magnetic pressures) is of critical importance for an economic magnetic fusion reactor. At the forefront of this endeavour is the field-reversed configuration. Here we demonstrate the kinetic stabilizing effect of fast ions on a disruptive magneto-hydrodynamic instability, known as a tilt mode, which poses a central obstacle to further field-reversed configuration development, by energetic beam injection. This technique, combined with the synergistic effect of active plasma boundary control, enables a fully stable ultra-high-beta (approaching 100%) plasma with a long lifetime.

  20. Achieving highly-enhanced UV photoluminescence and its origin in ZnO nanocrystalline films

    Science.gov (United States)

    Thapa, Dinesh; Huso, Jesse; Morrison, John L.; Corolewski, Caleb D.; McCluskey, Matthew D.; Bergman, Leah

    2016-08-01

    ZnO is an efficient luminescent material in the UV-range ∼3.4 eV with a wide range of applications in optical technologies. Sputtering is a cost-effective and relatively straightforward growth technique for ZnO films; however, most as-grown films are observed to contain intrinsic defects which can significantly diminish the desirable UV-emission. In this research the defect dynamics and optical properties of ZnO sputtered films were studied via post-growth annealing in Ar or O2 ambient, with X-ray diffraction (XRD), imaging, transmission and Urbach analysis, Raman scattering, and photoluminescence (PL). The imaging, XRD, Raman and Urbach analyses indicate significant improvement in crystal morphology and band-edge characteristics upon annealing, which is nearly independent of the annealing environment. The native defects specific to the as-grown films, which were analyzed via PL, are assigned to Zni related centers that luminesce at 2.8 eV. Their presence is attributed to the nature of the sputtering growth technique, which supports Zn-rich growth conditions. After annealing, in either environment the 2.8 eV center diminished accompanied by morphology improvement, and the desirable UV-PL significantly increased. The O2 ambient was found to introduce nominal Oi centers while the Ar ambient was found to be the ideal environment for the enhancement of the UV-light emission: an enhancement of ∼40 times was achieved. The increase in the UV-PL is attributed to the reduction of Zni-related defects, the presence of which in ZnO provides a competing route to the UV emission. Also, the effect of the annealing was to decrease the compressive stress in the films. Finally, the dominant UV-PL at the cold temperature regime is attributed to luminescent centers not associated with the usual excitons of ZnO, but rather to structural defects.

  1. Fearful foragers: honey bees tune colony and individual foraging to multi-predator presence and food quality.

    Directory of Open Access Journals (Sweden)

    Ken Tan

    Full Text Available Fear can have strong ecosystem effects by giving predators a role disproportionate to their actual kill rates. In bees, fear is shown through foragers avoiding dangerous food sites, thereby reducing the fitness of pollinated plants. However, it remains unclear how fear affects pollinators in a complex natural scenario involving multiple predator species and different patch qualities. We studied hornets, Vespa velutina (smaller and V. tropica (bigger preying upon the Asian honey bee, Apis cerana in China. Hornets hunted bees on flowers and were attacked by bee colonies. Bees treated the bigger hornet species (which is 4 fold more massive as more dangerous. It received 4.5 fold more attackers than the smaller hornet species. We tested bee responses to a three-feeder array with different hornet species and varying resource qualities. When all feeders offered 30% sucrose solution (w/w, colony foraging allocation, individual visits, and individual patch residence times were reduced according to the degree of danger. Predator presence reduced foraging visits by 55-79% and residence times by 17-33%. When feeders offered different reward levels (15%, 30%, or 45% sucrose, colony and individual foraging favored higher sugar concentrations. However, when balancing food quality against multiple threats (sweeter food corresponding to higher danger, colonies exhibited greater fear than individuals. Colonies decreased foraging at low and high danger patches. Individuals exhibited less fear and only decreased visits to the high danger patch. Contrasting individual with emergent colony-level effects of fear can thus illuminate how predators shape pollination by social bees.

  2. Fearful foragers: honey bees tune colony and individual foraging to multi-predator presence and food quality.

    Science.gov (United States)

    Tan, Ken; Hu, Zongwen; Chen, Weiwen; Wang, Zhengwei; Wang, Yuchong; Nieh, James C

    2013-01-01

    Fear can have strong ecosystem effects by giving predators a role disproportionate to their actual kill rates. In bees, fear is shown through foragers avoiding dangerous food sites, thereby reducing the fitness of pollinated plants. However, it remains unclear how fear affects pollinators in a complex natural scenario involving multiple predator species and different patch qualities. We studied hornets, Vespa velutina (smaller) and V. tropica (bigger) preying upon the Asian honey bee, Apis cerana in China. Hornets hunted bees on flowers and were attacked by bee colonies. Bees treated the bigger hornet species (which is 4 fold more massive) as more dangerous. It received 4.5 fold more attackers than the smaller hornet species. We tested bee responses to a three-feeder array with different hornet species and varying resource qualities. When all feeders offered 30% sucrose solution (w/w), colony foraging allocation, individual visits, and individual patch residence times were reduced according to the degree of danger. Predator presence reduced foraging visits by 55-79% and residence times by 17-33%. When feeders offered different reward levels (15%, 30%, or 45% sucrose), colony and individual foraging favored higher sugar concentrations. However, when balancing food quality against multiple threats (sweeter food corresponding to higher danger), colonies exhibited greater fear than individuals. Colonies decreased foraging at low and high danger patches. Individuals exhibited less fear and only decreased visits to the high danger patch. Contrasting individual with emergent colony-level effects of fear can thus illuminate how predators shape pollination by social bees.

  3. A simple method for detection of food foraging behavior in the rat: involvement of NMDA and dopamine receptors in the behavior.

    Science.gov (United States)

    Li, F; Cao, W Y; Li, M B; Xu, Y; Zhang, J W; Zhang, J Y; Luo, X G; Dai, R P; Zhou, X F; Li, C Q

    2012-03-15

    Food foraging behavior involves food removing, hoarding, and competitive preying upon other animals. It is also associated with high cognitive functions such as investing effort into decision making, but no established laboratory model is available to detect the behaviors. In the present study, we have developed a novel laboratory rodent model to detect competitive, non-competitive, and no-hurdle foraging conditions that can mimic the corresponding environment in nature. We found that normal rats consistently foraged the food from a food container to the field and spread food into piles in the open field. There was no difference between male and female rats in the amount of foraged food in the competitive, non-competitive, and no-hurdle food foraging tests. The amount of foraged food was consistent each day for five consecutive days with a slight increase in following days. There was no significant difference in the amount of food foraged in the presence or absence of bedding materials. A dramatic decrease of foraged food was found in the rats after administration of haloperidol (dopamine D2 receptor antagonist) in the competitive, non-competitive, and no-hurdle food foraging tests. Treatment with MK-801 (non-competitive N-methy-D-aspartate receptor antagonist) reduced the foraged food in the competitive food foraging test, but did not affect the foraged food in the non-competitive and no-hurdle food foraging tests. Our study provides a simple but consistent analogue of natural food foraging behavior. Our study also suggests that dopaminergic and glutaminergic systems are differentially involved in the food foraging behaviors.

  4. The effects of using diagramming as a representational technique on high school students' achievement in solving math word problems

    Science.gov (United States)

    Banerjee, Banmali

    Methods and procedures for successfully solving math word problems have been, and continue to be a mystery to many U.S. high school students. Previous studies suggest that the contextual and mathematical understanding of a word problem, along with the development of schemas and their related external representations, positively contribute to students' accomplishments when solving word problems. Some studies have examined the effects of diagramming on students' abilities to solve word problems that only involved basic arithmetic operations. Other studies have investigated how instructional models that used technology influenced students' problem solving achievements. Still other studies have used schema-based instruction involving students with learning disabilities. No study has evaluated regular high school students' achievements in solving standard math word problems using a diagramming technique without technological aid. This study evaluated students' achievement in solving math word problems using a diagramming technique. Using a quasi-experimental experimental pretest-posttest research design, quantitative data were collected from 172 grade 11 Hispanic English language learners (ELLS) and African American learners whose first language is English (EFLLs) in 18 classes at an inner city high school in Northern New Jersey. There were 88 control and 84 experimental students. The pretest and posttest of each participating student and samples of the experimental students' class assignments provided the qualitative data for the study. The data from this study exhibited that the diagramming method of solving math word problems significantly improved student achievement in the experimental group (pvocabulary and symbols used in word problems and that both ELLs and EFLLs improved their problem solving success through careful attention to the creation and labeling of diagrams to represent the mathematics involved in standard word problems. Although Learnertype (ELL, EFLL

  5. Migrating Broad-billed Sandpipers achieve high fuelling rates by taking a multi-course meal

    NARCIS (Netherlands)

    Verkuil, Y.I.; Dekinga, A; Koolhaas, A; van der Winden, J; van der Have, T M; Chernichko, I I

    2006-01-01

    In spring, large numbers of migrating Broad-billed Sandpipers make a stop-over in the Sivash, a shallow lagoon system in the Crimea, Ukraine, between the Black Sea and the Sea of Azov. Observed fuelling rates are high and, in just a few weeks, the birds can build up sufficient departure mass to reac

  6. Academic Achievement and Emotional Intelligence: Predicting the Successful Transition from High School to University

    Science.gov (United States)

    Parker, James D. A.; Duffy, Jon M.; Wood, Laura M.; Bond, Barbara J.; Hogan, Marjorie J.

    2005-01-01

    This study examined the impact of emotional intelligence (EI) on the successful transition from high school to university. The short form of the Emotional Quotient Inventory (EQ-i) was completed by 1,426 first-year students attending four different universities within the first week of classes (September). At the end of the academic year (May),…

  7. Misery in Dark Shadows behind the High Achievement Scores in South Korean Schooling: An Ethnographic Study

    Science.gov (United States)

    Kwon, Soonjung; Kristjánsson, Kristján; Walker, David I.

    2017-01-01

    This article explores some of the hidden background behind the highly praised school results in South Korea. An ethnographic case study is used to cast light on how schooling is actually experienced by South Korean students. Two main results are reported from these data. First, evidence is presented of damaging "cultural elements" such…

  8. Recent Achievements in Developing Low Temperature and High Strain Rate Superplastic Materials

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper is to briefly outline our recent activities in developing low temperature or high strain rate superplastic materials, including aircraft-used and general-purpose Al- and Mg-base alloys or composites, as well as Ti3Al base intermetallic alloys. The processing routes applied included the thermomechanical treatment, equal channel angular pressing and other extrusion or forging methods.

  9. A Study of Organizational Justice, Organizational Citizenship Behavior, and Student Achievement in High Schools

    Science.gov (United States)

    Burns, W. R. Travis; DiPaola, Michael F.

    2013-01-01

    Emerging research suggests that teachers' perceptions of fairness with respect to interactions with school administrators, decision-making processes, and decision outcomes can contribute greatly to understanding effective schools. This study of Virginia public high schools used correlational analysis to measure the strength of the relationships…

  10. The Effects of Learning Styles on High School Students' Achievement on a Mathematics Course

    Science.gov (United States)

    Orhun, Nevin

    2013-01-01

    This study examined the relationship between learning styles of students and their success on a mathematics course. In this study, the categorization of high school students' learning style scores was defined. The given method for calculating the learning style scores was developed by the author. The purpose of this study was to raise the success…

  11. Bridging the High School and College Achievement Gap for Hispanics--It All Begins at Home

    Science.gov (United States)

    Cooper, Mary Ann

    2011-01-01

    According to a Pew Hispanic Center study, "Between Two Worlds: How Young Latinos Come of Age in America, Educational Expectations and Attainment," that surveyed Hispanics 16 years old and older, the high school dropout rate among Latino youths is nearly three times higher than that among white youths and nearly double the rate among blacks. Nearly…

  12. Achieving reversibility of ultra-high mechanical stress by hydrogen loading of thin films

    Science.gov (United States)

    Hamm, M.; Burlaka, V.; Wagner, S.; Pundt, A.

    2015-06-01

    Nano-materials are commonly stabilized by supports to maintain their desired shape and size. When these nano-materials take up interstitial atoms, this attachment to the support induces mechanical stresses. These stresses can be high when the support is rigid. High stress in the nano-material is typically released by delamination from the support or by the generation of defects, e.g., dislocations. As high mechanical stress can be beneficial for tuning the nano-materials properties, it is of general interest to deduce how real high mechanical stress can be gained. Here, we show that below a threshold nano-material size, dislocation formation can be completely suppressed and, when delamination is inhibited, even the ultrahigh stress values of the linear elastic limit can be reached. Specifically, for hydrogen solved in epitaxial niobium films on sapphire substrate supports a threshold film thickness of 6 nm was found and mechanical stress of up to (-10 ± 1) GPa was reached. This finding is of basic interest for hydrogen energy applications, as the hydride stability in metals itself is affected by mechanical stress. Thus, tuning of the mechanical stress-state in nano-materials may lead to improved storage properties of nano-sized materials.

  13. A Study of Organizational Justice, Organizational Citizenship Behavior, and Student Achievement in High Schools

    Science.gov (United States)

    Burns, W. R. Travis; DiPaola, Michael F.

    2013-01-01

    Emerging research suggests that teachers' perceptions of fairness with respect to interactions with school administrators, decision-making processes, and decision outcomes can contribute greatly to understanding effective schools. This study of Virginia public high schools used correlational analysis to measure the strength of the relationships…

  14. High-Stakes Choice: Achievement and Accountability in the Nation's Oldest Urban Voucher Program

    Science.gov (United States)

    Witte, John F.; Wolf, Patrick J.; Cowen, Joshua M.; Carlson, Deven E.; Fleming, David J.

    2014-01-01

    This article considers the impact of a high-stakes testing and reporting requirement on students using publicly funded vouchers to attend private schools. We describe how such a policy was implemented during the course of a previously authorized multi-year evaluation of the Milwaukee Parental Choice Program, which provided us with data on voucher…

  15. The Impact of High-Speed Internet Connectivity at Home on Eighth-Grade Student Achievement

    Science.gov (United States)

    Kingston, Kent J.

    2013-01-01

    In the fall of 2008 Westside Community Schools - District 66, in Omaha, Nebraska implemented a one-to-one notebook computer take home model for all eighth-grade students. The purpose of this study was to determine the effect of a required yearlong one-to-one notebook computer program supported by high-speed Internet connectivity at school on (a)…

  16. Overcoming Adversity: High-Achieving African American Youth's Perspectives on Educational Resilience

    Science.gov (United States)

    Williams, Joseph M.; Bryan, Julia

    2013-01-01

    This qualitative multicase research study identified the home, school, and community factors and processes that contributed to the academic success of 8 urban, African American high school graduates from low-income, single-parent families. Ten main themes emerged: school-related parenting practices, personal stories of hardship, positive…

  17. College Enrollment and Completion among Nationally Recognized High-Achieving Hispanic Students

    Science.gov (United States)

    Gurantz, Oded; Hurwitz, Michael; Smith, Jonathan

    2017-01-01

    Hispanic high school graduates have lower college completion rates than academically similar white students. As Hispanic students have been theorized to be more constrained in the college search and selection process, one potential policy lever is to increase the set of colleges to which these students apply and attend. In this paper, we…

  18. A Strategy to Achieve High-Efficiency Organolead Trihalide Perovskite Solar Cells

    Science.gov (United States)

    Andalibi, Shabnam; Rostami, Ali; Darvish, Ghafar; Moravvej-Farshi, Mohammad Kazem

    2016-11-01

    Recent theoretical and experimental reports have shown that organometal lead halide perovskite solar cells have attracted attention as a low-cost photovoltaic technology offering high power conversion efficiency. However, the photovoltaic efficiency of these materials is still limited by poor chemical and structural stability in the case of methylammonium lead triiodide and by large bandgap in the case of methylammonium lead tribromide or trichloride. To obtain high-performance devices, we have investigated the computationally optimal efficiency for these materials using the detailed-balance method and present optimal intermediate-band perovskite solar cells with high open-circuit voltage. We model different halide perovskites using density function theory calculations and study their bandgap and absorption coefficient. Based on calculation results, surprisingly Hg doping in different halide perovskites introduces a narrow partially filled intermediate band in the forbidden bandgap. We investigate electrical and optical properties of MAPb0.97Hg0.03I3, MAPb0.96Hg0.04Br3, and MAPb0.96Hg0.04Cl3 and calculate the high absorption efficiency of the different perovskite structures to create thin films suitable for photovoltaic devices.

  19. Misery in Dark Shadows behind the High Achievement Scores in South Korean Schooling: An Ethnographic Study

    Science.gov (United States)

    Kwon, Soonjung; Kristjánsson, Kristján; Walker, David I.

    2017-01-01

    This article explores some of the hidden background behind the highly praised school results in South Korea. An ethnographic case study is used to cast light on how schooling is actually experienced by South Korean students. Two main results are reported from these data. First, evidence is presented of damaging "cultural elements" such…

  20. The Effects of Learning Styles on High School Students' Achievement on a Mathematics Course

    Science.gov (United States)

    Orhun, Nevin

    2013-01-01

    This study examined the relationship between learning styles of students and their success on a mathematics course. In this study, the categorization of high school students' learning style scores was defined. The given method for calculating the learning style scores was developed by the author. The purpose of this study was to raise the success…