1,511 research outputs found
Portrait of author Jackson A. Graves, [s.d.]
No full textPhotographic portrait of author Jackson A. Graves, [s.d.]. Graves is shown from his upper torso to his head and is looking to the right. He is wearing a light-colored suit, a light shirt, and a dark tie with a square pattern. He has light-colored hair that is neatly combed and parted at left, a thick light mustache, and light eyebrows. There are large bags beneath his eyes and his ears are very big
Abundance of small individuals influences the effectiveness of processing techniques for deep-sea nematodes
No full textNematodes are the most abundant metazoans of deep-sea benthic communities, but knowledge of their distribution is limited relative to larger organisms. Whilst some aspects of nematode processing techniques, such as extraction, have been extensively studied, other key elements have attracted little attention. We compared the effect of (1) mesh size (63, 45, and 32 μm) on estimates of nematode abundance, biomass, and body size, and (2) microscope magnification (50 and 100×) on estimates of nematode abundance at bathyal sites (250-3100 m water depth) on the Challenger Plateau and Chatham Rise, south-west Pacific Ocean. Variation in the effectiveness of these techniques was assessed in relation to nematode body size and environmental parameters (water depth, sediment organic matter content, %silt/clay, and chloroplastic pigments). The 63-μm mesh retained a relatively low proportion of total nematode abundance (mean ±SD = 55 ±9%), but most of nematode biomass (90 ± 4%). The proportion of nematode abundance retained on the 45-μm mesh in surface (0-1 cm) and subsurface (1-5 cm) sediment was significantly correlated (P < 0.01) with %silt/clay (R² = 0.39) and chloroplastic pigments (R² = 0.29), respectively. Variation in median nematode body weight showed similar trends, but relationships between mean nematode body weight and environmental parameters were either relatively weak (subsurface sediment) or not significant (surface sediment). Using a low magnification led to significantly lower (on average by 43%) nematode abundance estimates relative to high magnification (P < 0.001), and the magnitude of this difference was significantly correlated (P < 0.05) with total nematode abundance (R²p = 0.53) and the number of small (≤ 250 μm length) individuals (R²p = 0.05). Our results suggest that organic matter input and sediment characteristics influence the abundance of small nematodes in bathyal communities. The abundance of small individuals can, in turn, influence abundance estimates obtained using different mesh sizes and microscope magnifications
Simulation and Control of a Pneumatic Muscle Actuator for a Rehabilitation Robot
No full textThe perfomance of a pneumatic muscle actuator, invented by Jim Hennequin and used in a prototype wheelchair-mounted robot ann designed by the first author is reported. Experimental measurements were made of the output torque versus rotary motion and internal pressure. The torque available for a muscle of size 60 mm width by 90 mm length ranges from 1 to 15 Nm. The rotary stiffness of this muscle is 0.081 Nm/deg. A simulation model of the dynamic behaviour of the muscle attached to the robot arm using one-dimensional flow theory was written in ACSL (Advanced Continuous Simulation Language). The resultant simulation gives good agreement to within ± 5% of the experimental values. Control using proportional and a PID controller is shown to be effective
Painted portrait of Father Geronimo Boscana, O.F.M., author of Chinigchinich, [s.d.]
No full textPhotograph of a painted portrait of Father Geronimo Boscana, O.F.M., author of "Chinigchinich", [s.d.]. The friar is at center, is shown from his upper torso to his head and is looking slightly to the right. He is wearing a light-colored hooded robe with the hood pulled halfway up his head. He has some thin white hair but is mostly bald. Chinigchinich was an account of California Indian life, focused on the Indians near San Juan Capistrano
Portrait of James Laughlin, author of "This Is My Blood," [s.d.]
No full textPhotographic portrait of James Laughlin, author of "This Is My Blood," [s.d.]. A elderly man with smiling eyes turns his face toward the camera. He has a slight smile on his face, and a large nose, bushy eyebrows and slicked-back graying hair. He wears a light-colored suit, striped tie, and undergarment.; The book was to be published March 3, 1989 in a limited edition by The Yolla Bolly Press
The skeletal carbonate contribution to mixed terrigenous-carbonate sediments on the temperate northeastern Northland continental shelf, New Zealand
No full textThe northeastern Northland continental shelf (NNCS) includes the coastal, shelf and uppermost slope seafloor out to depths of 210 m and over a distance of 150 km between North Cape and Ngurauru Bay slightly north of Whangarei. The nature of the surficial sediments covering NNCS is poorly known and this study uses archived and recently collected samples to begin to address this situation, with special attention to the nature and distribution of the skeletal carbonate fraction. The sediments are mainly neither carbonate-dominated as occurs in the Three Kings area immediately to the north, nor overwhelmingly terrigenous in nature as typifies more southern shelf sectors. Instead, mixed terrigenous-carbonate deposits prevail in an often patchwork mosaic distribution of facies. Carbonate content is often highest nearshore and in bays and harbours (50-80%), and generally decreases into deeper water (few-50%). The NNCS sediments are almost completely dominated by sand-sized components (60-90%) comprising gravelly sand, sand, muddy sand and gravelly muddy sand textures.
A sedimentary facies model is developed for the NNCS identifying five different facies. Facies 1 is siliciclastic quartzofeldspathic sand with minor bivalve contributions, occurring only in the northern sector. Subfacies 1a (quartz>feldspar) occurs at inner- to mid-shelf depths and is mainly derived from reworked Quaternary Karioitahi Group sand deposits and/or podzolisation and reworking of local soils. Subfacies 1b (feldspar>quartz) occurs in mid- to outer-shelf depths and is derived from the erosion of a combination of the Quaternary sand deposits (Katioitahi Group), Mesozoic basement rocks and Northland volcanic and sedimentary rocks. Facies 2 comprises mixed barnacle-siliciclastic gravel and sand at inner-shelf to uppermost slope depths in the northern sector and includes submarine basaltic and type 1 sedimentary rock fragments derived from Mesozoic basement rocks and the Tangihua Complex of the Northland Allochthon. Facies 3 consists of mixed calcareous red algae and bivalve-siliciclastic gravel and sand at inner- to mid-shelf depths in the southern sector and involves a mix of relict and modern skeletal material and sedimentary rock fragments type 2 sourced from Tertiary deposits. Facies 4 is mixed foraminiferal-siliciclastic sand and mud and occurs only in the very southern sector in two subfacies. Subfacies 4a, a mixed benthic foraminiferal-siliciclastic sand, occurs in mid-shelf depths and comprises plagioclase dominated siliciclastic material sourced from Mesozoic basement rocks. Subfacies 4b, a mixed planktic foraminiferal-siliciclastic sand and mud, occurs in mid- to outer-shelf depths and comprises rock fragments derived from Tertiary deposits which could also be a local source of the reworked planktic foraminifera at these depths. Facies 5 consists of mixed bryozoan-siliciclastic sand at mid-shelf depths and in scattered locations across the NNCS associated with rocky outcrops for bryozoan attachment. Siliciclastic material comprises plagioclase sand sourced from reworking of Mesozoic basement rocks, and sedimentary rock fragments type 2 sourced from Tertiary sediments.
The NNCS sedimentary facies model is compared with other temperate carbonate shelf models and carbonate-rich North Island shelf sectors, including Hauraki Gulf, Three Kings platform, north Kaipara continental margin and Wanganui shelf, which serves to both test and expand scenarios of cool-water carbonate sedimentation established for New Zealand. Overall, the mixed terrigenous-carbonate material on the NNCS comprises an often mosaic facies distribution with the skeletal fraction dominated by bivalve and barnacle fragments and a mixture of relict and modern material. These characteristics reflect several environmental controls, including (a) diversified substrate types (rock, shell, sand, mud); (b) variable supply and dispersal routes of terrigenous material linked to positions of hinterland estuaries/harbours and rocky versus sandy coastlines; (c) scattered and discrete areas of primary carbonate generation (the “carbonate factories”) and the subsequent selective transportation of skeletal grains; (d) local effects of nutrient-rich upwelling; and (e) the variable mix of relict and modern sediment associated with the post-glacial rise of sea level since about 20 ka
Fields of activity significance scientific college students [Campos de significación de la actividad científica en estudiantes universitarios]
No full textThis study has as purpose to show the beliefs, attitudes, knowledge and stereotypes of university students about scientific research. In order to reach it, the author carried out an exercise based on associative questions, individual and group interviews and a multiple choice questionnaire that was proposed to 273 students enrolled at two university centers at Guadalajara University (Universidad de Guadalajara). The information was then analyzed by means of the mixed content technique (open answers) and the statistic program SPSS (multiple choice questionnaire). The results show that most of the interview students have erroneous conceptions about the scientific duty and a very imprecise picture about the scientist and the domain and space in which he/she works. Since those social representations have been built throughout the student's academic life by several media (formal and informal), the author considers that it is essential to analyze them in order to increase the interest about scientific activity amongst the students
Fields of activity significance scientific college students [Campos de significación de la actividad científica en estudiantes universitarios]
No full textThis study has as purpose to show the beliefs, attitudes, knowledge and stereotypes of university students about scientific research. In order to reach it, the author carried out an exercise based on associative questions, individual and group interviews and a multiple choice questionnaire that was proposed to 273 students enrolled at two university centers at Guadalajara University (Universidad de Guadalajara). The information was then analyzed by means of the mixed content technique (open answers) and the statistic program SPSS (multiple choice questionnaire). The results show that most of the interview students have erroneous conceptions about the scientific duty and a very imprecise picture about the scientist and the domain and space in which he/she works. Since those social representations have been built throughout the student's academic life by several media (formal and informal), the author considers that it is essential to analyze them in order to increase the interest about scientific activity amongst the students
Portrait of Helen Fiske Hunt Jackson, author of Ramona, [s.d.]
No full textPhotographic portrait of Helen Fiske Hunt Jackson, author of "Ramona", [s.d.]. Mrs. Jackson is pictured standing, wearing an elaborate dress with a huge bustle, made of what appears to be silk or satin. Her hands are folded across her waist while she looks to the right. She appears to be in her middle-age and wears the large locks of her curly hair pulled back from her face. She can be seen smiling, while a chair supports her dress to the right. Picture file card reads: "An American novelist, poet, and general writer, born at Amherst, mass. October 18, 1831; died at San Francisco, CA, August 12, 1885. She was the daughter of Professor Fiske, of Amherst. He first husband, Capt. E.B. Hunt, died in 1863. In 1870, she published a volume entitled "Verses". Her first prose volume, "Bits of Travel" (1872), was followed by "Bits of Talk About Home Matters" (1873), and "Bits of Travel at Home" (1878). In 1875 she married Mr. W.S. Jackson, of Colorado Springs. Here, she published "A Century of Dishonor", relating to the dealings of the U.S. Government with the Indians. This led to her appointment in 1883 as a special commissioner to examine into the condition and needs of the Mission Indians. After visiting the different tribes, she wrote "Ramona"(1884), a novel relating to the Mission Indians. Mrs. Jackson had previously written two novels in the "no Name" seires: "Mercy Philbric's Chioce" ["Choice"?] (1876) and "Hetty's Strange History"(1877). Besides these works, she published "The Story of Boon", a poem (1879), the training of children(1882), and several books for young people: "Nellie's Silver Mine" (1878), "Mammy Tittleback and her Family" (1881), and "The Hunter Cats of Connorloa" (1884). Since her death have appeared "Glimpses of Three Coasts", "Sonnets and Lyrics", "Zeph", a novel (1886), and "Between Whiles" (1887)"
Insignificant enhancement of export flux in the highly productive subtropical front, east of New Zealand: a high resolution study of particle export fluxes based on Th-234: U-238 disequilibria
No full textWe evaluated the export fluxes of Particulate Organic Carbon (POC) in the Subtropical Frontal zone (STF) of the SW Pacific sector of the Southern Ocean. The site is characterized by enhanced primary productivity, which has been suggested to be stimulated through so-called natural iron fertilization processes where iron-depleted subantarctic water (SAW) mixes with mesotrophic, iron-replete subtropical water (STW). We adopted the small-volume Th-234 method to achieve the highest possible spatial sampling resolution in austral late autumn-early winter, May-June, 2008. Inventories of chlorophyll-a, particulate Th-234 and POC observed in the upper 100 m were all elevated in the mid-salinity water type (34.5 34.8) salinity waters which were of STW origin with low macronutrients. However, Steady-State Th-234 fluxes were similar across the salinity gradient being, 25 +/- 0.78 ((1.5 +/- 0.047) x 10(3)) in the mid-salinity, and 29 +/- 0.53 ((1.8 +/- 0.032) x 10(3)) and 22 +/- 1.1 Bq m(-2) d(-1) ((1.3 +/- 0.066) x 10(3) dpm m(-2) d(-1)) in the high and low salinity waters respectively. Bottle POC/Th ratios at the depth of 100 m were used to convert Th-234 fluxes into POC export fluxes. The derived POC flux did not appear to be enhanced in mid-salinity waters where the primary productivity was inferred to be the highest at the time of sampling, with a flux of 11 +/- 0.45 mmol C m(-2) d(-1), compared to 14 +/- 0.39 mmol C m(-2) d(-1) in high salinity waters and 8.5 +/- 0.66 mmol C m(-2) d(-1) in low salinity waters. This study thus implied that natural iron fertilization does not necessarily lead to an enhancement of POC export in STF regions
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