230 research outputs found
Chlorophyll-c from marine algae and its characterization as natural dye for dye-sensitized solar cells.
No full textMarine algae (seaweeds) have a broad range of applications in several productive sectors, from human consumption to pharmacology, cosmetics, agriculture and waste water treatments. Algal biomass are also employed in the field of renewable energies for the production of biogas. Marine algae are indeed a reserve of natural dyes (Chls a, b and c), being therefore potentially suitable in PV technology for their low cost and easy attainability, without potential environmental load in terms of land subtraction. Chlorophyll-c is a photosynthetic pigment, a porfirine molecule, presents only in brown algae. Undaria pinnatifida (known as Wakame) is largely present in Venice Lagoon and for it a disposal strategy is recommended.
In this study, a low cost and eco-friendly extraction protocol was developed to obtain chlorophyll-c from brown alga Undaria pinnatifida, for utilization in dye-sensitized solar cells (DSSCs), along with the characterization of optical absorption and spectroscopy of the dye. Photovoltaic performances of the chlorophyll-based devices were also tested by measuring current-voltage curves as well as the incident photon to current efficiency. Three different solvents were tested, whose polarity was modified with different dilution with water. Better chlorophyll-c was extracted using 60% of acetone, whereas Ritchie algorithms were used to determine chlorophyll concentrations. The UV absorbance spectrum of chlorophyll extract exhibits the characteristic absorption peaks at 630 nm, confirming the presence of chl-c. The DSSC has delivered a short-circuit photocurrent density (Jsc) of 1.739 mA/cm2, open circuit photo-voltage (Voc) of 0.407 V, fill factor (FF) of 0.67, an efficiency (η) of 0.49% and a maximum incident photon-to-current conversion efficiency (IPCEmax) of 16% atthe Soret peak. The data presented here, improving η and IPCEmax , exceed the prior art of our previous study.[1] Obtained data suggest that protocols developed are useful to get an optimum amount of chlorophyll-c and that the DSSC performance indicates the possible use of marine algae in sustainable energy technologies.[1] G. Calogero, I. Citro, G. Di Marco, S. Armeli Minicante, M. Morabito and G. Genovese, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 117 (2014) 702
Bicalutamide monotherapy versus flutamide plus goserelin in prostate cancer: Updated results of a multicentric trial
No full textOBJECTIVES:
To compare the efficacy of bicalutamide monotherapy to maximal androgen blockade in advanced prostatic cancer.
PATIENTS AND METHODS:
Previously untreated patients with histologically proven stage C or D (American Urological Association Staging System) disease were randomly allocated to either bicalutamide (B) or goserelin plus flutamide (G+F). After disease progression, patients treated with B were assigned to castration. The primary endpoint for this trial was overall survival. Prostate cancer-specific survival and progression were included among secondary endpoints.
RESULTS:
In total 108 patients received B and 112 received G+F. At a median follow-up time of 54 months (range 1-89), 151 patients progressed and 113 died. There was no significant difference in the duration of either progression-free or overall survival. Hazards of progression, death and cancer-specific death, corrected by disease stage, tumor grade and baseline PSA level, showed that patients initially assigned to B had a higher risk of progression but a comparable risk of death and cancer-specific death with the exception of patients with G3 tumors who had an increased risk of death).
CONCLUSIONS:
In patients with well or moderately well differentiated tumors, B monotherapy followed by castration may offer the same survival chance as maximal androgen deprivation. In those patients it thus represents a reasonable choice that can avoid the side effects of androgen deprivation for considerable periods of time
ECONOMIC ANALYSIS IN DISPUTES OVER TRADE REMEDY AND RELATED MEASURES IN AGRICULTURE, WITH EXAMPLES FROM RECENT CASES
No full textInternational Relations/Trade,
Photoelectrochemical and spectrophotometric studies on dye-sensitized solar cells (DSCs) and stable modules (DSCMs) based on natural apocarotenoids pigments
No full textThe overwhelming influence of ptarmigan abundance on gyrfalcon reproductive success in the central Yukon, Canada
No full textCompanion studies of Willow Ptarmigan (Lagopus lagopus) and Gyrfalcons (Falco rusticolus) in the central Yukon from 1978 to 1983 allowed us to examine Gyrfalcon reproductive performance at 14 nest sites in relation to ptarmigan abundance and other potential effects, including weather variables, the previous year’s success, nest site characteristics, and Golden Eagle (Aquila chrysaetos) nesting density. Ptarmigan abundance declined six-fold and was mirrored by a significant decline in Gyrfalcon breeding success (breeding failure 58%, clutch desertion 33%). Clutch size showed little variation, although deserted nests held fewer eggs than did successful nests, and there were more four-egg clutches when ptarmigan were most abundant. An average of 2.26 young fledged per nest during abundant ptarmigan years, and 0.l8 when ptarmigan were declining. No other factors were correlated with Gyrfalcon reproductive success. Juvenile ptarmigan density had a compensatory effect: even when ptarmigan breeding numbers dipped, Gyrfalcons bred successfully if the proportion of juvenile ptarmigan was high. Clutch initiation date was a good predictor of Gyrfalcon breeding performance. Early clutches had more eggs (67% with 4 eggs compared to 27% in late nests), were less likely to be deserted (5% vs. 59%), and fledged more young (93% vs. 38%). Two Gyrfalcon pairs, supplemented with food in a poor ptarmigan year, fledged young at a rate and schedule comparable to pairs during a peak ptarmigan year. We discuss interesting observations about Gyrfalcon brood success, as well as Golden Eagle nesting density as a potentially important aspect of the reproductive ecology of Gyrfalcons in this population.Peer reviewedAuthor's reprint from Gyrfalcons and ptarmigan in a changing world
Uso do amostrador de GIBBS na estimação de valores genéticos em dados categóricos simulados.
No full texto objetivon este estudo foi avaliar o efeito de diferentes informaçõesa priori (P), tamanhos de cadeia( C), bum-1n(B ) e thinning( T) sobre os valores genéticos a ditivos diretos e maternos na avaliação de características a tegóricas. Foram simulados rebanhos com 40 touros e 1.200 fêmeas, a casalados aleatoriamente acompanhados por 20 anos, e gerados efeitos a ditivos direto e materno e de ambiente permanentem a terno. Foram g eradas duas repetições de cada combinação P x Cx B x T, os componentes de (co)variãncia e os valores genéticos foram estimados por inferência bayesiana e obtida a correlação de Pearson entre os valores genéticos estimados e os verdadeiros d entro de cada categoria animal. Os valores de herdabilidade direta (h2a)e materna ( h2m) foram subestimados para todas as análises. Houve efeito da interaçãoC x B e C x T para aconvergência da h2a, para a h2m foi encontrado efeito de C. Para todas as categorias houve efeito de C x B x T, não tendo sido encontrado efeito da priori sobre as correlações
Options for Supply Management in Canada with Trade Liberalization
No full textFollowing the Uruguay Round of trade negotiations Canada replaced its import quotas on sensitive products with tariff rate quotas. The over-quota tariffs on those products operating under domestic supply management schemes (dairy and poultry products) ranged from a low of 155 percent on turkey to a high of 299 percent on butter. These tariffs have effectively blocked over quota imports and are likely to continue to prevent imports, under most market conditions, given the likely range of tariff cuts proposed for sensitive products following a successful completion of the Doha Round. However, it’s argued that tariff cuts in the post-Doha Round will severely limit Canada’s ability to restrict imports and it is important to use the next 15 years to better position the supply managed industries to compete at that time. The paper reviews a number of reform options that could be pursued ranging from a full buy-out of current marketing quotas, the introduction of two types of marketing quota, to providing partial compensation of short-term income losses. The advantages and disadvantages of each option are discussed with respect to their costs and impacts on income and asset values.Canada, trade liberalization, supply management, Demand and Price Analysis, International Relations/Trade,
AN ANALYSIS OF A UNITED STATES-CANADA-MEXICO FREE TRADE AGREEMENT
No full textThis is one of two papers commissioned by the International Agricultural Trade Research Consortium on various aspects related to the agricultural sector of a prospective North American Free Trade Agreement. The companion paper to this one has been prepared by a working group chaired by Richard Barichello, University of British Columbia. To minimize duplication with the Barichello paper this paper has given greater attention to the role of Mexico, currency exchange rates, and explicit modeling of the trade relationship.International Relations/Trade,
Bicalutamide monotherapy versus flutamide plus goserelin in prostate cancer: updated results of a multicentric trial.
No full text- …
