2,608 research outputs found
Modeling Probability of Path Loss for DSDV, OLSR and DYMO above 802.11 and 802.11p
This paper presents path loss model along with framework for probability
distribution function for VANETs. Furthermore, we simulate three routing
protocols Destination Sequenced Distance Vector (DSDV), Optimized Link State
Routing (OLSR) and Dynamic MANET On-demand (DYMO) in NS-2 to evaluate and
compare their performance using two Mac-layer Protocols 802.11 and 802.11p. A
novel approach of this work is modifications in existing parameters to achieve
high efficiency. After extensive simulations, we observe that DSDV out performs
with 802.11p while DYMO gives best performance with 802.11.Comment: IEEE 8th International Conference on Broadband and Wireless
Computing, Communication and Applications (BWCCA'13), Compiegne, Franc
Human Gait Recognition Subject to Different Covariate Factors in a Multi-View Environment
Human gait recognition system identifies individuals based on their biometric traits. A human’s biometric features can be grouped into physiologic or behavioral traits. Biometric traits, such as the face [1], ears [2], iris [3], finger prints, passwords, and tokens, require highly accurate recognition and a well-controlled human interaction to be effective. In contrast, behavioral traits such as voice, signature, and gait do not require any human interaction and can be collected in a hidden and non-invasive mode with a camera system at a low resolution. In comparison with other physiological traits, one of the main advantages of gait analysis is the collection of data from a certain distance. However, gait is less powerful than physiological traits, yet it still has widespread application in surveillance for unfavorable situations. From traditional algorithms to deep learning models, a gait survey provides a detailed history of gait recognition
Contribution of Endogenous Glucocorticoids and Their Intravascular Metabolism by 11β-HSDs to Postangioplasty Neointimal Proliferation in Mice
Exogenous glucocorticoids inhibit neointimal proliferation in animals. We aime to test the hypothesis that endogenous glucocorticoids influence neointimal proliferation; this may be mediated by effects on systemic risk factors or locally in vessels, and modulated either by adrenal secretion or by enzymes expressed in vessels which mediate local inactivation (11β-HSD2 in endothelium) or regeneration (11β-HSD1 in smooth muscle) of glucocorticoids. Femoral artery wire-angioplasty was conducted in C57Bl/6J, Apo-E(−/−), 11β-HSD1(−/−), Apo-E, 11β-HSD1(−/−) (double knockout) and 11β-HSD2(−/−) mice following glucocorticoid administration, adrenalectomy, glucocorticoid or mineralocorticoid receptor antagonism, or selective 11β-HSD1 inhibition. In C57Bl/6J mice, neointimal proliferation was reduced by systemic or local glucocorticoid administration, unaffected by adrenalectomy, reduced by the mineralocorticoid receptor antagonist eplerenone, and increased by the glucocorticoid receptor antagonist RU38486. 11β-HSD2 deletion had no effect on neointimal proliferation, with or without eplerenone. 11β-HSD1 inhibition or deletion had no effect in chow-fed C57Bl/6J mice, but reduced neointimal proliferation in Apo-E(−/−) mice on Western diet. Reductions in neointimal size were accompanied by reduced macrophage and increased collagen content. We conclude that pharmacological administration of glucocorticoid receptor agonists or of mineralocorticoid receptor antagonists may be useful in reducing neointimal proliferation. Endogenous corticosteroids induce beneficial glucocorticoid receptor activation and adverse mineralocorticoid receptor activation. However, manipulation of glucocorticoid metabolism has beneficial effects only in mice with exaggerated systemic risk factors, suggesting effects mediated primarily in liver and adipose rather than intra-vascular glucocorticoid signalling. Reducing glucocorticoid action with 11β-HSD1 inhibitors that are being developed for type 2 diabetes appears not to risk enhanced neointimal proliferation
Effect of various dopant elements on primary graphite growth
Five spheroidal graphite cast irons were investigated, a usual ferritic grade and four pearlitic alloys containing Cu and doped with Sb, Sn and Ti. These alloys were remelted in a graphite crucible, leading to volatilization of the magnesium added for spheroidization and to carbon saturation of the liquid. The alloys were then cooled down and maintained at a temperature above the eutectic temperature. During this step, primary graphite could develop showing various features depending on the doping elements added. The largest effects were that of Ti which greatly reduces graphite nucleation and growth, and that of Sb which leads to rounded agglomerates instead of lamellar graphite. The samples have been investigated with secondary ion mass spectrometry to enlighten distribution of elements in primary graphite. SIMS analysis showed almost even distribution of elements, including Mg and Al (from the inoculant) in the ferritic grade, while uneven distribution was evident in all doped alloys. Investigations are going on to clarify if the uneven distribution is associated with structural defects in the graphite precipitates
Colloidal Single-Layer Photocatalysts for Methanol-Storable Solar Hâ‚‚ Fuel
Molecular surfactants are widely used to control low-dimensional morphologies, including 2D nanomaterials in colloidal chemical synthesis, but it is still highly challenging to accurately control single-layer growth for 2D materials. A scalable stacking-hinderable strategy to not only enable exclusive single-layer growth mode for transition metal dichalcogenides (TMDs) selectively sandwiched by surfactant molecules but also retain sandwiched single-layer TMDs' photoredox activities is developed. The single-layer growth mechanism is well explained by theoretical calculation. Three types of single-layer TMDs, including MoS2 , WS2 , and ReS2 , are successfully synthesized and demonstrated in solar H2 fuel production from hydrogen-stored liquid carrier-methanol. Such H2 fuel production from single-layer MoS2 nanosheets is COx -free and reliably workable under room temperature and normal pressure with the generation rate reaching ≈617 µmole g-1 h-1 and excellent photoredox endurability. This strategy opens up the feasible avenue to develop methanol-storable solar H2 fuel with facile chemical rebonding actualized by 2D single-layer photocatalysts
Heat stress develops with increased total-tract gut permeability, and dietary organic acid and pure botanical supplementation partly restores lactation performance in Holstein dairy cows
To evaluate the effects of heat stress (HS) conditions
and dietary organic acid and pure botanical (OA/PB)
supplementation on gut permeability and milk produc-
tion, we enrolled 46 multiparous Holstein cows [208 ±
4.65 dry matter intake (DMI; mean ± SD), 3.0 ± 0.42
lactation, 122 ± 4.92 d pregnant, and 39.2 ± 0.26 kg
of milk yield] in a study with a completely randomized
design. Cows were assigned to 1 of 4 groups: thermo-
neutral conditions (TN-Con, n = 12), HS conditions
(HS-Con, n = 12), thermoneutral conditions pair-fed
to HS-Con (TN-PF, n = 12), or HS supplemented with
OA/PB [75 mg/kg of body weight (BW); 25% citric
acid, 16.7% sorbic acid, 1.7% thymol, 1.0% vanillin,
and 55.6% triglyceride; HS-OAPB, n = 10]. Supple-
ments were delivered twice daily by top-dress; all cows
not supplemented with OA/PB received an equivalent
amount of the triglyceride used for microencapsulation
of the OA/PB supplement as a top-dress. Cows were
maintained in thermoneutrality [temperature-humidity
index (THI) = 68] during a 7-d acclimation and covari-
ate period. Thereafter, cows remained in thermoneutral
conditions or were moved to HS conditions (THI: diur-
nal change 74 to 82) for 14 d. Cows were milked twice
daily. Clinical assessments and BW were recorded,
blood was sampled, and gastrointestinal permeability
measurements were repeatedly evaluated. The mixed
model included fixed effects of treatment, time, and
their interaction. Rectal and skin temperatures and res-
piration rates were greater in HS-Con and HS-OAPB
relative to TN-Con. Dry matter intake, water intake,
and yields of energy-corrected milk (ECM), protein,
and lactose were lower in HS-Con relative to HS-OAPB.
Nitrogen efficiency was improved in HS-OAPB relative
to HS-Con. Compared with TN-Con and TN-PF, milk
yield and ECM were lower in HS-Con cows. Total-
tract gastrointestinal permeability measured at d 3 of
treatment was greater in HS-Con relative to TN-Con
or TN-PF. Plasma total fatty acid concentrations were
reduced, whereas insulin concentrations were increased
in HS-Con relative to TN-PF. We conclude that expo-
sure to a heat-stress environment increases total-tract
gastrointestinal permeability. This study highlights
important mechanisms that might account for milk
production losses caused by heat stress, independent
of changes in DMI. Our observations also suggest
that dietary supplementation of OA/PB is a means to
partly restore ECM production and improve nitrogen efficiency in dairy cattle experiencing heat stress
A study of size-dependent properties of MoS2 monolayer nanoflakes using density-functional theory
Novel physical phenomena emerge in ultra-small sized nanomaterials. We study the limiting small-size-dependent properties of MoS2 monolayer rhombic nanoflakes using density-functional theory on structures of size up to Mo35S70 (1.74 nm). We investigate the structural and electronic properties as functions of the lateral size of the nanoflakes, finding zigzag is the most stable edge configuration, and that increasing size is accompanied by greater stability. We also investigate passivation of the structures to explore realistic settings, finding increased HOMO-LUMO gaps and energetic stability. Understanding the size-dependent properties will inform efforts to engineer electronic structures at the nano-scale
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