Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink

Terrestrial ecosystem models commonly represent vegetation in terms of plant functional types (PFTs) and use their vegetation attributes in calculations of the energy and water balance as well as to investigate the terrestrial carbon cycle. Sub-grid scale variability of PFTs in these models is represented using different approaches with the "composite" and "mosaic" approaches being the two end-members. The impact of these two approaches on the global carbon balance has been investigated with the Canadian Terrestrial Ecosystem Model (CTEM v 1.2) coupled to the Canadian Land Surface Scheme (CLASS v 3.6). In the composite (single-tile) approach, the vegetation attributes of different PFTs present in a grid cell are aggregated and used in calculations to determine the resulting physical environmental conditions (soil moisture, soil temperature, etc.) that are common to all PFTs. In the mosaic (multi-tile) approach, energy and water balance calculations are performed separately for each PFT tile and each tile's physical land surface environmental conditions evolve independently. Pre-industrial equilibrium CLASS-CTEM simulations yield global totals of vegetation biomass, net primary productivity, and soil carbon that compare reasonably well with observation-based estimates and differ by less than 5% between the mosaic and composite configurations. However, on a regional scale the two approaches can differ by > 30%, especially in areas with high heterogeneity in land cover. Simulations over the historical period (1959–2005) show different responses to evolving climate and carbon dioxide concentrations from the two approaches. The cumulative global terrestrial carbon sink estimated over the 1959–2005 period (excluding land use change (LUC) effects) differs by around 5% between the two approaches (96.3 and 101.3 Pg, for the mosaic and composite approaches, respectively) and compares well with the observation-based estimate of 82.2 ± 35 Pg C over the same period. Inclusion of LUC causes the estimates of the terrestrial C sink to differ by 15.2 Pg C (16%) with values of 95.1 and 79.9 Pg C for the mosaic and composite approaches, respectively. Spatial differences in simulated vegetation and soil carbon and the manner in which terrestrial carbon balance evolves in response to LUC, in the two approaches, yields a substantially different estimate of the global land carbon sink. These results demonstrate that the spatial representation of vegetation has an important impact on the model response to changing climate, atmospheric CO₂ concentrations, and land cover

The influence of soils on heterotrophic respiration exerts a strong control on net ecosystem productivity in seasonally dry Amazonian forests

Net ecosystem productivity of carbon (NEP) in seasonally dry forests of the Amazon varies greatly between sites with similar precipitation patterns. Correctly modeling the NEP seasonality with terrestrial ecosystem models has proven difficult. Previous modelling studies have mostly advocated for incorporating processes that act to reduce water stress on gross primary productivity (GPP) during the dry season, such as deep soils and roots, plant-mediated hydraulic redistribution of soil moisture, and increased dry season leaf litter generation which reduces leaf age and thus increases photosynthetic capacity. Recent observations, however, indicate that seasonality in heterotrophic respiration also contributes to the observed seasonal cycle of NEP. Here, we use the dynamic vegetation model CLASS-CTEM (Canadian Land Surface Scheme–Canadian Terrestrial Ecosystem Model) – without deep soils or roots, hydraulic redistribution of soil moisture, or increased dry season litter generation – at two Large-Scale Biosphere–Atmosphere Experiment (LBA) sites (Tapajós km 83 and Jarú Reserve). These LBA sites exhibit opposite seasonal NEP cycles despite reasonably similar meteorological conditions. Our simulations are able to reproduce the observed NEP seasonality at both sites. Simulated GPP, heterotrophic respiration, latent and sensible heat fluxes, litter fall rate, soil moisture and temperature, and basic vegetation state are also compared with available observation-based estimates which provide confidence that overall the model behaves realistically at the two sites. Our results indicate that representing the effect of soil moisture on heterotrophic respiration in terms of soil matric potential and constraining heterotrophic respiration when absolute soil matric potential is both low (wetter soils) and high (drier soils), with optimum conditions in between, allows %appropriately representing the influence of soil texture and depth, %through soil moisture, on seasonal patterns of GPP and, especially, % heterotrophic respiration is important to correctly simulate NEP seasonality

Meander Line EBG Based Multiband Antenna for WLAN and WiMAX application

There have been many investigations in the past regarding the design of multi- band antennas. A multiband antenna is the one in which the same antenna can be operated at different frequencies. There have been many approaches towards the design of the multiband antenna like stacked patches, parasitic patches, use of slots, shaping i.e., the use of notches, reactive loading, slot loaded patches etc. The use of slots is an easier approach towards the design of multiband an- tenna as there is a well defined theoretical approach towards the design of the slot antennas. These slots can be cut either in the patch or in the ground plane as needed for the application. Higher gain is an important requirement for an antenna and use of Electromagnetic Band-Gap structures(EBG) is one of the promising technique to achieve this. The present thesis work focuses on the design of multiband antenna as well as novel Electromagnetic Band-Gap structures and their integration for enhance- ment of the gain of the antenna at desired frequencies of operation. The multi- band antenna is designed by cutting slots in the ground plane and the Uniplanar EBG is employed for the gain enhancement. The Fractalized Meander Line EBG based Microstrip Patch Slot Antenna oper- ates in the 6-7 GHz (Extended C-Band) and has a fractional bandwidth of 13% , and it maintains the radiation characteristics in the desired band with gain rang- ing from 5.5 to 7 dB. The Meander Line EBG based Multiband Antenna operates in the WLAN and WiMAX bands at frequencies 2.4, 3.6, 5.2 GHz respectively having gain 3.5 , 4.2 and 6.19 d

Comparison of oral nifedipine and oral labetalol as a single drug therapy for control of blood pressure in preeclampsia

Background: Worldwide hypertension during pregnancy is a common cause of maternal and fetal morbidity and mortality. Effective control of blood pressure is one of the important steps in management of preeclampsia. Few drugs like nifedipine, labetalol, methyldopa, and hydralazine have acceptable high safety profile during pregnancy.Methods: In this study 120 antenatal women with non-severe preeclampsia were compared by giving either nifedipine or labetalol as a single drug therapy for control of blood pressure. Various parameters like control of blood pressure, side effects of drugs, gestational age at the time of delivery, mode of delivery, any complication and perinatal outcome were assessed.Results: In this study authors found that in both group, adequate control of blood pressure was achieved. This study shows slightly higher rate of pre term delivery and LSCS with labetalol and minimal side effects with nifedipine but difference in each group is insignificant.Conclusions: Labetalol and nifedipine both the drugs are equally effective in reducing blood pressure and any of it can safely be used as a first choice of drug for management of hypertension in preeclampsia and it can be decided as per clinician’s experience and familiarity with drug

Reentrant phase transition in charged colloidal suspensions

We report the observation of a novel phase transition in dilute aqueous suspensions of polystyrene particles as a function of ionic impurity concentration C. The suspension phase separates into dense and rare phases only for a restricted range of C which depends on particle concentration n. The dense phase has liquidlike or crystalline order depending on n and C. Free energies of the homogeneous and the phase-separated states are calculated with an effective interparticle potential. The calculated phase diagram is in qualitative agreement with the present experimental results

State-insensitive trapping of Rb atoms: linearly versus circularly polarized lights

We study the cancellation of differential ac Stark shifts in the 5s and 5p states of rubidium atom using the linearly and circularly polarized lights by calculating their dynamic polarizabilities. Matrix elements were calculated using a relativistic coupled-cluster method at the single, double and important valence triple excitations approximation including all possible non-linear correlation terms. Some of the important matrix elements were further optimized using the experimental results available for the lifetimes and static polarizabilities of atomic states. "Magic wavelengths" are determined from the differential Stark shifts and results for the linearly polarized light are compared with the previously available results. Possible scope of facilitating state-insensitive optical trapping schemes using the magic wavelengths for circularly polarized light are discussed. Using the optimized matrix elements, the lifetimes of the 4d and 6s states of this atom are ameliorated.Comment: 13 pages, 13 tables and 4 figure

Congenital granular cell lesion in newborn mandible

Congenital granular cell lesion (CGCL) is a rare non-neoplastic lesion found in newborns also known as Neumann’s tumor. This benign lesion occurs predominantly in females mostly as a single mass. The histogenesis and natural history of the lesion remains obscure. It arises from the mucosa of the gingiva, either from the maxillary or mandibular alveolar ridge. The lesion is more common in the maxillary alveolar ridge than the mandibular.The present report describes a case of congenital granular cell lesion in an eight-day-old female child who was born with a mass on the anterior mandibular alveolar ridge. The mass was protruding from her mouth and compromised feeding. A clinical diagnosis of teratoma was suggested. Histologically, cells of this lesion are identical to granular cell tumor (neuroectodermal type) and show intense diastase-resistant Periodic Acid Schiff positivity. Immunohistochemically, cells are positive for vimentin but negative for S-100 and desmin, thus suggesting that CGCL is possibly derived from primitive gingival mesenchymal cells rather than having schwannian origin.Key words: Congenital epulis, congenital granular cell lesion, immunohistochemistr

Kinetics of Various Chemical Changes During Storage of Processed Cheese

Three batches of processed cheese (PC) were manufactured by the standard procedure and packed aseptically in polystyrene (Sunpet) pet jars with screw cap of about 200 g capacity and stored at 5, 30 and, 45°C. The PC samples were analysed for proximate composition, selected physico-chemical characteristics and sensory attributes at intervals of 7 days for the product stored at 5°C upto 56 days, 3 days for the product stored at 30°C upto 6 days and 24 days at 45°C till the sample became organoleptically unacceptable. The results revealed that 30°C was conducive for mold growth, due to which the product got spoiled after 8 days of storage and hence the studies were terminated at this temperature. An increasing trend was observed in all the chemical parameters except pH with increase in time of storage at all the temperatures. The reaction rate constants for all the chemical parameters, followed a zero order reaction and were higher at higher temperature of storage as compared to lower temperatures. The least square analysis of variance for the chemical parameters had no significant differences between batches, while there was a significant to highly significant difference between storage period and temperature of storage

GLYCOSYLTRANSFERASES OF RAT BRAIN THAT MAKE CEREBROSIDES: SUBSTRATE SPECIFICITY, INHIBITORS, AND ABNORMAL PRODUCTS 1

Brain homogenates from young rats were assayed for their ability to synthesize cerebrosides from radioactive UDP-galactose or UDP-glucose and ceramide. A comparison of galactose transfer with ceramides made from different 2-hydroxy acids showed that the shortest one tested (C 7 ) was by far the best acceptor, while the poorest contained 18 carbon atoms; longer fatty acids were better than CIS. Glucosyltransferase, on the other hand, showed rather little chain length specificity or discrimination against hydroxy acid ceramides. Synthetic compounds analogous in structure to ceramides were tested as inhibitors of the sugar transferases. Some were found to act as sugar acceptors themselves, particularly amides of DL-erythro-1- phenyl-2-amino-1,3-propanediol. Some amides were good inhibitors of glucosyltransferase, particularly decanoyl norephedrine, decanoyl threo-1-phenyl-2-amino-1,3-propanediol and decenoyl phenylalaninol. The secondary amine analogous to the first of these, N -decyl norephedrine, was also very effective. No strong inhibitors of galactosyl transferase were found, although octanoyl D-threo- p -nitrophenyla- minopropanediol showed promise (42% inhibition at 0.3 mM). Octanoyl phenylalaninol was nearly as good an inhibitor; the inhibition appeared only after a lag period. It is suggested that the glucosyltransferase inhibitors might he useful in therapy of Gaucher's disease, by reducing the degradative load normally falling on glucocerebrosidase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65833/1/j.1471-4159.1976.tb06987.x.pd