299 research outputs found
Water Footprint Differences of Producing Cultivars of Selected Crops in New Zealand
Water footprint (WF) is a measure of the amount of water used to produce goods and services. It is a very important concept on indicating how much water can be consumed to complete a process of growing or processing a product at a particular location. However, paucity of water footprint information in countries facing increased competition for water resources between industries limits market access and profit optimization. Water footprint differences of producing selected cultivars of potato, oca and pumpkin squash were determined under irrigation and rain-fed regimes. All crop husbandry practices were followed in potato, oca (3.3 plants m−2) and pumpkin squash (2.2 plants m−2). Water footprint was determined as the ratio of volume of evapotranspiration for irrigated and rain-fed crops plus grey water to total yield. The consumptive water use for the rain-fed crop was 75, 65 and 69% of the irrigated oca, potato and pumpkin squash, respectively, with high water consumption in heritage cultivars. The water footprint was low in pumpkin squash and highest in oca, while potato cultivars were intermediate. Irrigation reduced water footprint especially in crops more responsive to irrigation. Farmers should focus on improving the harvest index and irrigation to reduce water footprint
Incorporating the geometry of dispersal and migration to understand spatial patterns of species distributions
Dispersal and migration can be important drivers of species distributions. Because the paths followed by individuals of many species are curvilinear, spatial statistical models based on rectilinear coordinates systems would fail to predict population connectivity or the ecological consequences of migration or species invasions. I propose that we view migration/dispersal as if organisms were moving along curvilinear geometrical objects called smooth manifolds. In that view, the curvilinear pathways become the ‘shortest realised paths’ arising from the necessity to minimise mortality risks and energy costs. One can then define curvilinear coordinate systems on such manifolds. I describe a procedure to incorporate manifolds and define appropriate coordinate systems, with focus on trajectories (1D manifolds), as parts of mechanistic ecological models. I show how a statistical method, known as ‘manifold learning’, enables one to define the manifold and the appropriate coordinate systems needed to calculate population connectivity or study the effects of migrations (e.g. in aquatic invertebrates, fish, insects and birds). This approach may help in the design of networks of protected areas, in studying the consequences of invasion, range expansions, or transfer of parasites/diseases. Overall, a geometrical view to animal movement gives a novel perspective to the understanding of the ecological role of dispersal and migration
Nuclei, Superheavy Nuclei and Hypermatter in a chiral SU(3)-Modell
A model based on chiral SU(3)-symmetry in nonlinear realisation is used for
the investigation of nuclei, superheavy nuclei, hypernuclei and multistrange
nuclear objects (so called MEMOs). The model works very well in the case of
nuclei and hypernuclei with one Lambda-particle and rules out MEMOs. Basic
observables which are known for nuclei and hypernuclei are reproduced
satisfactorily. The model predicts Z=120 and N=172, 184 and 198 as the next
shell closures in the region of superheavy nuclei. The calculations have been
performed in self-consistent relativistic mean field approximation assuming
spherical symmetry. The parameters were adapted to known nuclei.Comment: 19 pages, 11 figure
Bilijarna funkcija u radnika profesionalno izloženih aluminijskoj prašini i dimu
This study investigated billiary secretory function in workers occupationally exposed to aluminium dust and fumes. It included a group of 34 male workers aged (44.1±7.8) years and exposed up to 4.6 mg m-3 of aluminium dust and fumes in workplace air for (21.6±2.5) years, and a group of 30 unexposed control male workers. Serum and urine aluminium levels were measured in both groups before and after chelating treatment with 1 g deferoxamine by intramuscular injection. Billiary function was assessed by measuring gamma-glutamyl transpeptidase, alkaline phosphatase, 5-nucleotidase, cholesterol and its fractions, total and indirect bilirubin, and bile acids. We then analysed the relationship between Al exposure and billiary function. In the exposed group mean serum aluminium was significantly higher [(4.91±3.86) µg L-1] than in controls. The same was true for urine Al before [(1.57±1.93) µg L-1] and after deferoxamine [(11.51±14.97) µg L-1]. Total and indirect bilirubin and alkaline phosphatase were significantly higher in the exposed than in control workers, and they correlated with urine Al after the chelating treatment. Our findings suggest that chronic occupational exposure to aluminium dust and fumes leads to a significant body retention of aluminium. The impaired biliary secretion in the exposed workers manifested itself in subclinical signs of cholestasis.Eksperimentalna istraživanja na životinjama pokazuju da kronična izloženost aluminiju može izazvati smanjen prijenos organskih aniona preko žučnih kanalića, što ima za posljedicu poremećaje sekrecije žuči i kolestazu. Učinci kronične izloženosti aluminiju na bilijarnu funkciju u ljudi do sada nisu istraživani. Procjenjivali smo učinke na bilijarnu funkciju radnika koji su profesionalno izloženi prašini i dimu aluminija. U izloženoj skupini bila su 34 muškarca, životne dobi (44,1±7,8) godina koji su tijekom (21,6±2,5) godina bili izloženi razini do 4,6 mg m-3 prašine i dima aluminija. Kontrolna skupina sastojala se od 30 neizloženih radnika. Vrijednosti aluminija određene su u serumu i mokraći u obje skupine prije i nakon davanja kelatirajućeg spoja (deferoksamin u dozi od 1 g im.). Za procjenu bilijarne funkcije rabljeni su ovi pokazatelji: γ-glutamil transpeptidaza, alkalna fosfataza, 5-nukleozidaza, kolesterol, ukupni i indirektni bilirubin te žučne kiseline. Analizirana je korelacija između izloženosti aluminiju i bilijarne funkcije. Srednja vrijednost Al u serumu izloženih radnika [(4,91±3,86) µg L-1], kao i koncentracije Al u mokraći prije [(1,57±1,93) µg L-1] i nakon primjene kelatirajućeg spoja [(11,5±15,0) µg L-1] bile su statistički značajno više u odnosu na vrijednosti u kontrolnih ispitanika. Vrijednosti ukupnog i indirektnoog bilirubina te alkalne fosfataze bile su statistički značajno više u izloženih radnika i pozitivno su korelirale s ukupnim Al izlučenim mokraćom nakon primjene kelatora. Može se zaključiti da kronična profesionalna izloženost prašini i dimu aluminija dovodi do tjelesnog opterećenja aluminijem i poremećaja bilijarne funkcije, što se odražava supkliničkim znakovima kolestaze
Quantum Size Effect transition in percolating nanocomposite films
We report on unique electronic properties in Fe-SiO2 nanocomposite thin films
in the vicinity of the percolation threshold. The electronic transport is
dominated by quantum corrections to the metallic conduction of the Infinite
Cluster (IC). At low temperature, mesoscopic effects revealed on the
conductivity, Hall effect experiments and low frequency electrical noise
(random telegraph noise and 1/f noise) strongly support the existence of a
temperature-induced Quantum Size Effect (QSE) transition in the metallic
conduction path. Below a critical temperature related to the geometrical
constriction sizes of the IC, the electronic conductivity is mainly governed by
active tunnel conductance across barriers in the metallic network. The high 1/f
noise level and the random telegraph noise are consistently explained by random
potential modulation of the barriers transmittance due to local Coulomb
charges. Our results provide evidence that a lowering of the temperature is
somehow equivalent to a decrease of the metal fraction in the vicinity of the
percolation limit.Comment: 21 pages, 8 figure
Priority for the Worse Off and the Social Cost of Carbon
The social cost of carbon (SCC) is a monetary measure of the harms from carbon emission. Specifically, it is the reduction in current consumption that produces a loss in social welfare equivalent to that caused by the emission of a ton of CO2. The standard approach is to calculate the SCC using a discounted-utilitarian social welfare function (SWF)—one that simply adds up the well-being numbers (utilities) of individuals, as discounted by a weighting factor that decreases with time. The discounted-utilitarian SWF has been criticized both for ignoring the distribution of well-being, and for including an arbitrary preference for earlier generations. Here, we use a prioritarian SWF, with no time-discount factor, to calculate the SCC in the integrated assessment model RICE. Prioritarianism is a well-developed concept in ethics and theoretical welfare economics, but has been, thus far, little used in climate scholarship. The core idea is to give greater weight to well-being changes affecting worse off individuals. We find substantial differences between the discounted-utilitarian and non-discounted prioritarian SCC
Sodium yttrium fluoride based upconversion nano phosphors for biosensing
In the present study, NaYF4-Yb3+/Er3+ having the composition NaYF4-18%Yb3+/2%Er3+ and NaYF4-20%Yb3+/2%Er3+ with and without the addition of PVP (polyvinyl pyrolidone) have been synthesised by a solution method using NaF, yttrium nitrate, ytterbium nitrate and erbium nitrate as precursors. Upconversion spectra of prepared nanomaterial under 980 nm laser excitation have been studied. The variation in upconversion spectra with new born calf serum and myoglobin has been studied. Myoglobin (Mb) may be helpful when used in conjunction with other cardiac markers for rapid determination of acute myocardial ischemia, especially in patients with a typical chest pain or nonspecific ECG changes. The variation of UC fluorescence with addition of Mb indicates the suitability of using NaYF4 based UC nanoparticles in cardiac marker detection. The detailed study is currently under progress
- …