Quantifying spatial variability of selected soil trace elements and their scaling relationships using multifractal techniques.

Multifractal techniques were utilized to quantify the spatial variability of selected soil trace elements and their scaling relationships in a 10.24-ha agricultural field in northeast China. 1024 soil samples were collected from the field and available Fe, Mn, Cu and Zn were measured in each sample. Descriptive results showed that Mn deficiencies were widespread throughout the field while Fe and Zn deficiencies tended to occur in patches. By estimating single multifractal spectra, we found that available Fe, Cu and Zn in the study soils exhibited high spatial variability and the existence of anomalies ([α(q)max-α(q)min]≥0.54), whereas available Mn had a relatively uniform distribution ([α(q)max-α(q)min]≈0.10). The joint multifractal spectra revealed that the strong positive relationships (r≥0.86, P<0.001) among available Fe, Cu and Zn were all valid across a wider range of scales and over the full range of data values, whereas available Mn was weakly related to available Fe and Zn (r≥0.18, P<0.01) but not related to available Cu (r = -0.03, P = 0.40). These results show that the variability and singularities of selected soil trace elements as well as their scaling relationships can be characterized by single and joint multifractal parameters. The findings presented in this study could be extended to predict selected soil trace elements at larger regional scales with the aid of geographic information systems

Maize yield response to water supply and fertilizer input in a semi-arid environment of Northeast China.

Maize grain yield varies highly with water availability as well as with fertilization and relevant agricultural management practices. With a 311-A optimized saturation design, field experiments were conducted between 2006 and 2009 to examine the yield response of spring maize (Zhengdan 958, Zea mays L) to irrigation (I), nitrogen fertilization (total nitrogen, urea-46% nitrogen,) and phosphorus fertilization (P2O5, calcium superphosphate-13% P2O5) in a semi-arid area environment of Northeast China. According to our estimated yield function, the results showed that N is the dominant factor in determining maize grain yield followed by I, while P plays a relatively minor role. The strength of interaction effects among I, N and P on maize grain yield follows the sequence N+I >P+I>N+P. Individually, the interaction effects of N+I and N+P on maize grain yield are positive, whereas that of P+I is negative. To achieve maximum grain yield (10506.0 kg · ha(-1)) for spring maize in the study area, the optimum application rates of I, N and P are 930.4 m(3) · ha(-1), 304.9 kg · ha(-1) and 133.2 kg · ha(-1) respectively that leads to a possible economic profit (EP) of 10548.4 CNY · ha(-1) (CNY, Chinese Yuan). Alternately, to obtain the best EP (10827.3 CNY · ha(-1)), the optimum application rates of I, N and P are 682.4 m(3) · ha(-1), 241.0 kg · ha(-1) and 111.7 kg · ha(-1) respectively that produces a potential grain yield of 10289.5 kg · ha(-1)

Dopamine D2 receptor-mediated regulation of partner preferences in female prairie voles (Microtus ochrogaster): a mechanism for pair bonding

This study examined the role of dopamine (DA) in partner preference (PP) formation in female prairie voles (Microtus ochrogaster). The nonspecific DA antagonist haloperidol blocked mating-induced PP, whereas the nonspecific DA agonist apomorphine induced PP without mating. The D2 antagonist eticlopride, but not the Dl antagonist SCH23390, blocked PP, whereas the D2 agonist quinpirole, but not the Dl agonist SKF38393, induced PP without mating. Injections of eticlopride before or immediately after mating, but not 24 hr after mating, impaired PP, indicating that DA&apos;s effects were not due to an interference with mating or sensory recognition. Finally, intracerebroventricular injections of eticlopride diminished PP. Together, these data suggest that mating-induced PP requires activation of D2 receptors and that social experience may activate dopaminergic pathways, with enduring effects on behavior. Recent studies have begun to explore the neural mechanisms underlying complex social behaviors such as pair bonding (Young, Wang, &amp; Insel, 1997). Pair bonds are long-term, selective social attachments that are characteristic of social organization in human and other primate societies. Pair bonds can also be studied in monogamous, nonprimate species. Monogamous mammals, by definition, form long-term, selective attachments. Several recent studies have demonstrated that pair bond formation can be operationally defined and rigorously measured in the laboratory. One of the earliest and most important measures of the pair bond is the formation of a partner preference, a simple test of whether the individual chooses to affiliate with a partner more than a stranger (Carter &amp; Getz, 1993). In a laboratory setting, partner preference formation can serve as a quantifiable indication of pair bonding (Insel, Preston, &amp