Modeling of urban trees’ effects on reducing human exposure to UV radiation in Seoul,Korea

A mathematical model is constructed for quantifying urban trees’ effects on mitigating the intensity of ultraviolet (UV) radiation on the ground within different land use types across a city. The model is based upon local field data, meteorological data and equations designed to predict the reduced UV fraction due to trees at the ground level. Trees in Seoul, Korea (2010), produced average UV protection factors (UPF) for pedestrians in tree shade at solar noon (May to August) of 8.3 for park and cemetery land uses and 3.0 for commercial and transportation land uses. The highest daily UPF was 11.8 in the park and cemetery land uses, which has the highest percent canopy cover. This UV model is being implemented within the i-Tree modeling system to allow cities across the world to estimate tree effects on UV exposure. Understanding the impacts of urban trees on UV exposure can be used in developing landscape design strategies to help protect urban populations from UV exposure and consequent health impacts.     

Dimensionality-driven insulator-to-metal transition in the bechgaard salts

Optical experiments were conducted on a series of organic linear chain conductors with different values of the interchain single-electron transfer integral tb, which quantifies the degree of anisotropy. Electron-electron interactions together with Umklapp scattering resulted in a correlation gap and an insulating state for small tb. An insulator-to-metal transition was observed when tb exceeded a critical value, on the order of the correlation gap Egap. The absence of a plasma edge on the insulator side of the transition for polarization perpendicular to the chains suggests that the electrons are confined to the chains. The optical features of the metallic state, when contrasted with the magnetic properties, are suggestive of spin-charge separation.     

Site of acid-base relevant ion transfer in the gills of rainbow trout (Oncorhynchus mykiss) exposed to environmental hypercapnia

In order to delineate the contribution of primary vs. secondary circulatory circuits in the gill for acid-base and ionic regulation, the flow and composition of the fluids in the central venous sinus (CVS) and the systemic circuit of rainbow trout were studied by application of a previously developed microcannulation technique during normocapnic and hypercapnic conditions. The average haematocrit (Hct) of blood from dorsal aorta (DA) and sinus venosus (SV) ranged from 20.1 to 26.7%, whereas average Hct in the fluid from the branchial vein (BV), representing drainage from the central venous sinus (CVS), was in the range of 4.2 to 7.0%. Under normocapnic conditions, the largest fraction of cardiac output, 92.9%, was directed through the systemic vascular circuit, whereas the CVS circuit was perfused with 7.1 % of cardiac output. Hypercapnia did not significantly affect the blood flow distribution between the two circuits. The pattern of acid-base regulation in dorsal aortic blood reflected the characteristic response of fish exposed to environmental hypercapnia. Upon initiation of environmental hypercapnia (2% CO₂), plasma P_{CO 2} was elevated in all three flow compartments (CVS, DA, SV), inducing an extracellular respiratory acidosis of about 0.4 pH units. pH and [HCO₃ ^-] values in the DA were consistently lower, than those for both CVS and SV sites throughout the hypercapnic period. During the 8h of exposure plasma bicarbonate concentration was elevated by about 12 mM, complemented by a fall in extracellular [Cl^-] of about 10 mM in all three compartments. The amount of HCO₃ ^- gained at the CVS site during 8h of hypercapnia (3.3 mmol · kg^-1) exceeds the amount accumulated in the extracellular space (2.1 mmol·kg^-1), suggesting the CVS as the main site of ionic acid-base regulation in trout.     

Influence of agricultural traffic and crop management on collembola and microbial biomass in arable soil

Collembola and microbial biomass C were investigated in a field experiment with controlled agricultural traffic and crop rotation over a period of 27 months. The wheel-induced compactive efforts were applied according to management practices within the crop rotation of sugar beet, winter wheat, and winter barley. Increasing wheel traffic produced increasing soil compaction, mainly due to a reduction in surface soil porosity. Increasing soil compaction was accompanied by a decrease in microbial biomass C and the density of collembola. The influence of soil compaction on microbial biomass C was smaller than that of the standing crop. However, for collembola, especially euedaphic species, a reduction in pore space appeared to be of more importance than the effects of a standing crop. Within the crop rotation, microbial biomass C and the density of collembola increased in the order sugar beet, winter wheat, and winter barley.     

Impact of the use of biofertilizers on cotton ( Gossypium hirsutum ) crop under irrigated agro-ecosystem

High nitrogen fixing, phosphate solubilizing, phytohormones producing isolates of Azotobacter, Azospirillum, Acetobacter and Pseudomonas were used as inoculants for cotton. Important cultures were selected on the basis of their effect on root/shoot length and chemotactic behaviour. Selected bioinoculants were earlier tested for their beneficial properties like nitrogen fixation (ARA), ammonia excretion, IAA production etc. These bio-inoculants were further tested for phosphate solubilization property. Various chosen strains were tested with Desi (HD 123) and American (H 1098) cotton under field conditions (as for wheat). Plant height and boll weight were determined at the time of harvesting whereas survival rate of inoculated bacteria was determined after 30, 80 and 130 days respectively. In the year 2000–01, on the basis of boll number and boll weight plant^?1 AVK 51 (36; 76.2?g plant^?1), HT 57 (27; 56.9?g plant^?1), AC18 (33; 61.5?g plant^?1), Ala 27 (36; 61.4?g plant^?1) and Pseudomonas (34; 71.3?g plant^?1) were identified as significant both for American and desi cotton varieties. Highest survival rate was observed with Mac 68 (33.4 × 10⁵) followed by HT54 (31.5 × 10⁵) after 30 days of sowing, which decreased after 80 days and remained constant up to 130 days. This trend was observed with all the cultures. Similar results were observed in 2001–02. 25?kg ha^?1 N saving was observed with A. chroococcum (AVK51) bioinoculant for cotton crop.     

Relation of potato size to after-cooking blackening tendency

An observation made in the laboratory led to a two-year study showing a relationship between after-cooking discoloration and potato size. This relationship, the larger the potato the greater the blackening tendency, was consistent for all potatoes examined in this sudy whether they blackened severely or slightly. These findings may help future researchers correct the conditions that cause blackening.     

Oxygen delivery to the fish eye: blood flow in the pseudobranchial artery of rainbow trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>)

Similar to gas secretion into the swimbladder, some teleosts also exhibit ocular gas secretion to supply their thick and avascular retina with oxygen. The process in the eye, however, is complicated by the fact that the retina is supplied with arterial blood only indirectly through the pseudobranch, a reduced gill arch of still unknown function. Approaches for closer analysis of the physiological implications of this serial blood supply arrangement and the associated process of O₂ release include complete unilateral vascular isolation of eye and/or pseudobranch while maintaining normal blood flow characteristics for undisturbed operation of the counter-current rete mirabile.Blood flow velocity in the afferent pseudobranchial artery (aPA; essentially equal to ophthalmic artery flow) of rainbow trout was measured by application of ultrasonic Doppler techniques. Accurate determination of flow rate in the untouched vessel was facilitated by mounting the Doppler crystal with a custom-made holder on the bone of the jaw and raw signal analysis by Fast Fourier Transformation for improved signal/noise ratio. Normal unilateral aPA blood flow was 746 l min^–1 kg^–1 body weight, (1.6% of cardiac output), the tissue-weight-specific blood flow was 3.6 ml min^–1 g^–1 for pseudobranch and 2.3 ml min^–1 g^–1 for the retina. Only about 28% of the oxygen potentially available with maximal activation of the Root effect is actually consumed in pseudobranch and retina. This generous supply of blood and the implicit safety margin may serve minimization of pH disturbances of retinal tissues, but may also come suitable during unilateral occlusion of supplying arteries for continued oxygen supply to the retinae. During contralateral occlusion, flow through the ipsilateral aPA increased to 136%. According to the normally low O₂ extraction, a minimal flow of 36% through bilateral anastomosis and contralateral ophthalmic artery may maintain complete contralateral oxygen supply.     

A comparison of the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts after calving in cows also given internal teat sealants

AIM: To compare, in cows treated with an internal teat sealant, the effect of short-acting and long-acting cloxacillin-based dry-cow therapy on somatic cell counts (SCC) after calving.

METHODS: Cows from a spring-calving, pasture-based dairy farm in the Manawatu-Whanganui region of New Zealand were randomly allocated to receive either a short-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=291) or a long-acting cloxacillin and ampicillin dry-cow therapy and internal teat sealant (n=288) at the end of lactation. Cows were managed on-farm with routine husbandry procedures through the dry period and following calving. A multivariable logistic regression model was used to determine the association between length of action of dry-cow therapy and the proportion of cows with a SCC >150,000?cells/mL at the first herd test after calving.

RESULTS: Age of cow, mean SCC for the preceding season and interval from calving to the first post-calving herd test were all associated with the proportion of cows with an individual SCC >150,000?cells/mL at the first herd test (p<0.001) Treatment with the short-acting dry-cow therapy was not associated with decreased odds of cows having a SCC >150,000?cells/mL at the first herd test compared with treatment with long-acting dry-cow therapy (OR=0.724; 95% CI=0.40–1.30).

CONCLUSIONS AND CLINICAL RELEVANCE: In this herd, which routinely used internal teat sealants, the use of short-acting cloxacillin-based dry-cow therapy did not result in an increased proportion of cows with elevated SSC post-calving. This was a single farm, single year study but indicates that in this herd, changing from a long-acting to a short-acting antimicrobial may have no impact on the prevalence of subclinical mastitis.