scholarly journals Sent to the Corner: xylem vessel anatomy not surface area determines megaphyll hydraulics in Cecropia obtusa Trécul (Urticaceae)

2018 ◽  
Author(s):  
Sébastien Levionnois ◽  
Sabrina Coste ◽  
Eric Nicolini ◽  
Clément Stahl ◽  
Hélène Morel ◽  
...  
Keyword(s):  
Cross Sections ◽  
Specific Conductivity ◽  
Secondary Growth ◽  
Cross Sectional ◽  
Positive Correlation ◽  
Leaf Level ◽  
Leaf Dimensions ◽  
Level Model ◽  
Primary Stem ◽  
Leaf Model

AbstractCorners rule predicts a positive correlation between leaf dimensions and the cross-sectional area of the primary stem. Although this relationship is usually explained by hydraulic and mechanical requirements, these hypotheses have never been tested empirically. However, Corner’s rule is tricky to investigate since rapid secondary growth of the stem prevents a rigorous link being established between a given leaf and the supporting stem. We chose a twig-like leaf model since petiole anatomy is only linked to the attached lamina. We tested the hypothesis that anatomical adjustments to hydraulic requirements related to vessel size enable reduced investment in tissue in the framework of Corner’s rule. We conducted a functional, mechanistic and intraspecific investigation of Cecropia obtusa Trécul, a Neotropical pioneer tree, by integrating morphological, anatomical and theoretical hydraulic traits around the lamina-petiole size relationship. The twig-like structure of the leaf and the strong lamina-petiole correlation of this model tree species made it possible to use the leaf-level model for a rigorous investigation of the functional implications of Corner’s rule. We found a positive correlation between petiole size, lamina size, the ratio of mean vessel area to vessel frequency in the petiole xylem and theoretical specific conductivity in the petiole xylem. Hydraulic function supports Corner’s rule to a lesser extent than previously thought. Variations in vessel dimensions mainly drive xylem hydraulic performances and avoid disproportionate petiole cross-sections to answer to hydraulic requirements associated with lamina size.

Gender determination of caucasoid hair using image analysis

1993 ◽  
Vol 51 ◽  
pp. 216-217
Author(s):  
T.B. Ball ◽  
W.M. Hess
Keyword(s):  
Image Analysis ◽  
Cross Sections ◽  
Scalp Hair ◽  
The Body ◽  
Equivalent Diameter ◽  
Cross Sectional ◽  
Hair Samples ◽  
Length Width ◽  
Morphological Differences

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.

Relationship of Sense of Coherence to Other Psychosocial Indices

2004 ◽  
Vol 20 (4) ◽  
pp. 227-236 ◽  
Author(s):  
Sara Holmberg ◽  
Anders Thelin ◽  
Eva-Lena Stiernström
Keyword(s):  
Social Support ◽  
Psychosocial Factors ◽  
Sense Of Coherence ◽  
Living Conditions ◽  
Strong Negative Correlation ◽  
Cross Sectional ◽  
Positive Correlation ◽  
Work Related ◽  
Job Demand ◽  
The Mean

Summary: The concept of “sense of coherence” (SOC) has been widely recognized since it was first introduced by Antonovsky. The originality and usefulness of the SOC scale and its relation to other psychosocial measures has been the subject of lively debate. The aim of this paper was to test for associations between SOC and work-related psychosocial factors (mainly the Job Demand-Control model), general living conditions, education, and social network factors. Cross-sectional data from a population-based sample of 1782 rural males from nine counties in Sweden were analyzed with a multiple regression technique. The subjects were occupationally active at inclusion and the mean age was 50 years (range 40-60). SOC was assessed with the original 29-item questionnaire. Psychosocial variables and lifestyle factors were assessed using questionnaires and structured interviews. The mean SOC among the subjects was 152.3 (standard deviation, 19.4). A strong negative correlation was found between SOC and job demand, whereas a positive correlation with job control was demonstrated. A positive correlation with general living conditions and with social support was also found. However, there was no correlation to education and occupation. Thus, SOC was shown to be strongly correlated to work-related psychosocial factors and social support, but independent of sociodemographic factors.

Automated 3D measurement of fiber cross section morphology in handsheets

2012 ◽  
Vol 27 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Christian Lorbach ◽  
Ulrich Hirn ◽  
Johannes Kritzinger ◽  
Wolfgang Bauer
Keyword(s):  
Image Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Image Plane ◽  
3D Measurement ◽  
Cross Sectional ◽  
Fiber Cross Section ◽  
Fiber Wall ◽  
Sectional Shape ◽  
Cross Section Geometry

Abstract We present a method for 3D measurement of fiber cross sectional morphology from handsheets. An automated procedure is used to acquire 3D datasets of fiber cross sectional images using an automated microtome and light microscopy. The fiber cross section geometry is extracted using digital image analysis. Simple sample preparation and highly automated image acquisition and image analysis are providing an efficient tool to analyze large samples. It is demonstrated that if fibers are tilted towards the image plane the images of fiber cross sections are always larger than the true fiber cross section geometry. In our analysis the tilting angles of the fibers to the image plane are measured. The resulting fiber cross sectional images are distorted to compensate the error due to fiber tilt, restoring the true fiber cross sectional shape. We use an approximated correction, the paper provides error estimates of the approximation. Measurement results for fiber wall thickness, fiber coarseness and fiber collapse are presented for one hardwood and one softwood pulp.

Can Cytokines be used as an Activation Marker in Rheumatoid Arthritis?

2020 ◽  
Vol 20 ◽  
Author(s):  
Fatih Öner Kaya ◽  
Yeşim Ceylaner ◽  
Belkız Öngen İpek ◽  
Zeynep Güneş Özünal ◽  
Gülbüz Sezgin ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Healthy Volunteers ◽  
Venous Blood ◽  
Cross Sectional Study ◽  
Joint Disease ◽  
Control Group ◽  
Cross Sectional ◽  
Positive Correlation ◽  
Das 28 ◽  
Tnf Α

Aims: The etiopathogenesis of Rheumatoid Arthritis (RA) is not clearly understood. However, the role of the cytokines takes an important part in this mechanism. We aimed to bring a new approach to the concept of 'remission' in patients with RA. Background: RA is a chronic, autoimmune, inflammatory disease that involves small joints in the form of symmetrical polyarthritis and progresses with exacerbations and remissions. Pain, swelling, tenderness and morning stiffness are typical of the joints involved. Although it is approached as a primary joint disease, a wide variety of extra-articular involvements may also occur. It is an interesting pathophysiological process, the exact cause of which is still unknown, with many environmental, genetic and potentially undiscovered possible factors in a chaotic manner. Objective: In this cross-sectional study, sedimentation rate (ESR), C- Reactive protein (CRP), Tumor necrosis factor (TNF)-α, soluble-TNF-α receptor (TNF-R), Interleukin (IL)-1B and IL-10 were measured in three groups which were healthy volunteers, patients with RA in the active period, and patients with RA in remission. Disease activity score-28 (DAS-28) was calculated in active RA and RA in remission. Methods: This study included 20 healthy volunteers, 20 remission patients with RA and 20 active RA patients. Venous blood samples were collected from patients in both healthy and RA groups. Results: RA group consisted 43 (71.6%) female and 17 (28.4%) male. Control group consisted 11 (55%) female and 9 (45%) male. TNF-R was significantly high only in the active group according to the healthy group (p=0.002). IL-10 was significantly high in active RA according to RA in remission (p=0.03). DAS-28 was significantly high in active RA according to RA in remission (p=0.001). In the active RA group, ESR and TNF-R had a positive correlation (r:0.442; p=0.048). In the active RA group, there was also a positive correlation between TNF-R and CRP (r:0.621; p=0,003). Both healthy and active RA group had significant positive correlation between ESR and CRP (r: 0.481; p=0.032 and r: 0,697; p=0,001 respectively). Conclusion: TNF-R can be the main pathophysiological factor and a marker showing activation. TNF-R can be very important in revealing the effect of TNF on the disease and the value of this effect in the treatment and ensuring the follow-up of the disease with CRP instead of ESR in activation.

Korelasi Dukungan Keluarga Dengan Respon Cemas Anak Saat Pemasangan Infus

2018 ◽  
Vol 3 (3) ◽  
pp. 467
Author(s):  
Diah Merdekawati ◽  
Dasuki Dasuki
Keyword(s):  
Coping Strategies ◽  
Family Support ◽  
Sampling Technique ◽  
Correlation Study ◽  
Research Data ◽  
School Age ◽  
Cross Sectional ◽  
Positive Correlation ◽  
Purposive Sampling ◽  
And Coping

<p><em>Pre-school age is particularly vulnerable to the effects of stress and fear during hospitalization. Children under the age of 6 are less able to think about an event as a whole, have not been able to determine behavior that can overcome the fear based on experience ever experienced and coping strategies ever done. The aims of this research to know correlation family support with child anxious response during infusion. This study was a quantitative with correlation study using cross sectional method. There were 51 respondents participated in this research. Data were collected through observation with purposive sampling technique. Then, data were analysed through univariate and bivariate. The result of univariate statistic test revealed that as much as 64.7% had good family support and 56.9% experienced an anxious response during infusion. The result of  bivariate statistic test showed that there was a positive correlation with moderate strength between family support and child's anxious response during infusion. This riset showed that families should provide support when children experience fear, anxiety and pain during infusion.</em></p><p><em><br /></em></p><p>Usia pra sekolah sangat rentan terhadap efek stress dan ketakutan selama rawat inap. Anak- anak dibawah usia 6 tahun kurang mampu berpikir tentang suatu peristiwa secara keseluruhan, belum bisa menentukan perilaku yang dapat mengatasi ketakutan berdasarkan pengalaman yang pernah dialami dan strategi koping yang pernah dilakukan. Tujuan penelitian ini adalah untuk mengetahui korelasi dukungan keluarga dengan respon cemas anak saat pemasangan infus. Penelitian ini merupakan penelitian kuantitatif studi korelatif dengan metode <em>cross secsional</em>. Sebanyak 51 responden terlibat dalam penelitian ini. Pengumpulan data melalui observasi. Pengambilan sampel dilakukan secara <em>purposive sampling. </em>Analisis data dilakukan secara <em>univariat </em>dan<em> bivariat. </em>Dari hasil uji statistik univariat diketahui sebanyak 64,7% memiliki dukungan keluarga baik dan 56,9% mengalami respon cemas saat pemasangan infus. Hasil uji statistik bivariat menunjukkan ada korelasi positif dengan kekuatan sedang antara dukungan keluarga dengan respon cemas anak saat pemasangan infus. Penelitian ini menunjukkan bahwa keluarga sebaiknya memberikan dukungannya pada saat anak mengalami ketakutan, kecemasan dan rasa nyeri pada saat pemasangan infus.</p><p><em><br /></em></p>

scholarly journals Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections

2021 ◽  
Vol 13 (6) ◽  
pp. 3255
Author(s):  
Aizhao Zhou ◽  
Xianwen Huang ◽  
Wei Wang ◽  
Pengming Jiang ◽  
Xinwei Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Heat Resistance ◽  
Cross Sections ◽  
Three Dimensional ◽  
Thermal Response ◽  
Transfer Efficiency ◽  
Cross Sectional ◽  
Heat Transfer Efficiency ◽  
Oval Tube

For reducing the initial GSHP investment, the heat transfer efficiency of the borehole heat exchange (BHE) system can be enhanced to reduce the number or depth of drilling. This paper proposes a novel and simple BHE design by changing the cross-sectional shape of the U-tube to increase the heat transfer efficiency of BHEs. Specifically, in this study, we (1) verified the reliability of the three-dimensional numerical model based on the thermal response test (TRT) and (2) compared the inlet and outlet temperatures of the different U-tubes at 48 h under the premise of constant leg distance and fluid area. Referent to the circular tube, the increases in the heat exchange efficiencies of the curved oval tube, flat oval tube, semicircle tube, and sector tube were 13.0%, 19.1%, 9.4%, and 14.8%, respectively. (3) The heat flux heterogeneity of the tubes on the inlet and outlet sides of the BHE, in decreasing order, is flat oval, semicircle, curved oval, sector, and circle shapes. (4) The temperature heterogeneity of the borehole wall in the BHE in decreasing order is circle, sector, curved oval, flat oval, and semicircle shapes. (5) Under the premise of maximum leg distance, referent to the heat resistance of the tube with a circle shape at 48 h, the heat exchange efficiency of the curved oval, flat oval, semicircle, and sector tubes increased 12.6%, 17.7%, 10.3%, and 7.8%, respectively. (6) We found that the adjustments of the leg distance and the tube shape affect the heat resistance by about 25% and 12%, respectively. (7) The flat-oval-shaped tube at the maximum leg distance was found to be the best tube design for BHEs.

Predictors of influenza vaccination uptake among elderly in Croatia

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
I Miskulin ◽  
A Vcev ◽  
M Matic Licanin ◽  
I Vcev ◽  
I Vukoja ◽  
...  
Keyword(s):  
Influenza Vaccination ◽  
Vaccination Coverage ◽  
Median Number ◽  
Cross Sectional ◽  
Positive Correlation ◽  
Positive Attitudes ◽  
Significant Difference ◽  
Vaccination History ◽  
Study Population ◽  
Effective Public Health

Abstract Background Influenza vaccination (IV) is recommended for elderly but vaccination coverage in this group remains unsatisfactory in Croatia. The aim of this study was to explore IV uptake among elderly from Eastern Croatia and predictors that influence this uptake. Methods This cross-sectional questionnaire study was conducted during 2018/2019 influenza season in convenient sample of older adults aged 65 years or more from Eastern Croatia at the primary health care setting. Results The study sample consisted of 816 subjects (48.0% males and 52.0% females). The median age of all subjects was 73.0 years (interquartile range (IQR) 69.5 - 79.0 years). The overall prevalence of IV uptake was 33.3%. The IV uptake was statistically more frequent among females (P &lt; 0.001) and old-old subgroup (85 years and older) (P &lt; 0.001). There was no statistically significant difference in IV uptake considering marital status of subjects (P &gt; 0.999). The median number of positive attitudes towards IV was 4.0 (IQR 2.0 - 4.0) and the median number of correct answers was 6.0 (IQR 4.0 - 8.0). The study revealed fair positive correlation between attitudes and IV uptake (rho=0.477; P &lt; 0.001) and poor positive correlation between knowledge and IV uptake (rho=0.242; P &lt; 0.001). The study further showed poor positive correlation between presence of comorbidities and IV uptake (rho=0.187; P &lt; 0.001) and moderate positive correlation between previous year vaccination history and IV uptake (rho=0.669; P &lt; 0.001). Conclusions The study showed that observed IV uptake is far below EU target influenza vaccination coverage among elderly of 75%. The study revealed that fairly good predictors of IV uptake in study population were gender, older age group, and previous year vaccination history while attitudes, knowledge and presence of comorbidities were fairly poor predictors. The good predictors of IV uptake among elderly should be taken into account during influenza vaccination popularization strategies development. Key messages Understanding the factors that could improve the acceptance of vaccination is crucial to design effective public health interventions. The structured communication campaigns on influenza and influenza vaccines should be developed and directed specifically to elderly as one of target groups for vaccination.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

Effects of Nano-Nozzles Cross-Sectional Geometry on Fluid Flow: Molecular Dynamic Simulation

2017 ◽  
Vol 34 (5) ◽  
pp. 667-678 ◽  
Author(s):  
H. Nowruzi ◽  
H. Ghassemi
Keyword(s):  
Fluid Flow ◽  
Velocity Profile ◽  
Cross Sections ◽  
Md Simulation ◽  
Flow Behavior ◽  
Water Model ◽  
Physical Parameters ◽  
Cross Sectional ◽  
Behavior Characteristics ◽  
Fanning Friction Factor

AbstractNano-nozzles are an essential part of the nano electromechanical systems (NEMS). Cross-sectional geometry of nano-nozzles has a significant role on the fluid flow inside them. So, main purpose of the present study is related to the effects of different symmetrical cross-sections on the fluid flow behavior inside of nano-nozzles. To this accomplishment, five different cross-sectional geometries (equilateral triangle, square, regular hexagon, elliptical and circular) are investigated by using molecular dynamics (MD) simulation. In addition, TIP4P is used for atomistic water model. In order to evaluate the fluid flow behavior, non-dimensional physical parameters such as Fanning friction factor, velocity profile and density number are analyzed. Obtained results are shown that the flow behavior characteristics appreciably depend on the geometry of nano-nozzle's cross-section. Velocity profile and density number for five different cross sections of nano-nozzle at three various measurement gauges are presented and discussed.

Do changes in light direction affect absorption profiles in leaves?

2010 ◽  
Vol 37 (5) ◽  
pp. 403 ◽  
Author(s):  
Craig R. Brodersen ◽  
Thomas C. Vogelmann
Keyword(s):  
Cross Sections ◽  
Incident Light ◽  
Monochromatic Light ◽  
Diffuse Light ◽  
Spongy Mesophyll ◽  
Light Regimes ◽  
Direct Light ◽  
Direct Measurements ◽  
Leaf Level

Leaf anatomy plays a functional role in propagating light through the leaf; palisade mesophyll has been shown to facilitate the channelling of collimated light deeper into the spongy mesophyll. Direct measurements of the propagation of diffuse light into the leaf, however, are absent. Using chlorophyll fluorescence imaging of leaf cross-sections, we measured light absorption profiles in leaves under direct (collimated), diffuse and low-angle monochromatic light. Low-angle and diffuse light was absorbed closer to the irradiated surface than direct light perpendicular to the surface. The shapes of internal absorption profiles indicated that leaves were influenced by the directional quality of the incident light. In addition, absorption profiles revealed that leaves were not simple light absorbing objects and that cellular anatomy influences the direction of light travelling into the mesophyll. These findings also suggest a mechanism for previously measured differences in leaf level photosynthesis under opposing light regimes.

Sign in / Sign up

Export Citation Format

Share Document