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Abstract Cereal/legume intercropping is becoming a popular production strategy for higher crop yields and net profits with reduced inputs and environmental impact. However, the effects of different spatial arrangements on the growth, grain yield, nitrogen uptake, and land-use advantage of wheat/soybean relay intercropping are still unclear, particularly under arid irrigated conditions. Therefore, in a three-year field study from 2018 to 2021, soybean was relay intercropped with wheat in different crop configurations (0.9 m, narrow strips; 1.8 m, medium strips; and 2.7 m, wide strips), and the results of intercropping systems were compared with their sole systems. Results revealed that intercrops with wide strips outperformed the narrow and medium strips, when the objective was to obtain higher total leaf area, dry matter, nitrogen uptake, and grain yield on a given land area due to reduced interspecific competition between intercrops. Specifically, at maturity, wide strips increased the dry matter accumulation (37% and 58%) and its distribution in roots (37% and 55%), straw (40% and 61%), and grains (30% and 46%) of wheat and soybean, respectively, compared to narrow strips. This enhanced dry matter in wide strips improved the soybean’s competitive ability (by 17%) but reduced the wheat’s competitive ability (by 12%) compared with narrow strips. Noticeably, all intercropping systems accumulated a significantly higher amount of nitrogen than sole systems, revealing that wheat/soybean relay intercropping requires fewer anthropogenic inputs (nitrogen) and exerts less pressure on the ecosystem than sole systems. Overall, in wide strips, intercropped wheat and soybean achieved 62% and 71% of sole wheat and soybean yield, respectively, which increased the greater total system yield (by 19%), total land equivalent ratio (by 24%), and net profit (by 34%) of wide strips compared to narrow strips. Our study, therefore, implies that the growth parameters, grain yields, nutrient accumulation, and land-use advantage of intercrop species could be improved with the proper spatial arrangement in cereal/legume intercropping systems.

To keep up with technology changes and industry trends, it is essential for Information Systems (IS) programs to maintain up to date curricula. In doing so, IS educators need to determine what the IS core is and implement it in their curriculum. This study performed a descriptive analysis of 2,229 core courses offered by 394 undergraduate IS programs in the United States. The result presents a panoramic snapshot of the IS core in the nation from the perspective of IS core curricula. By mapping those core courses to the most recent IS model curriculum, IS 2010, this study also reports how many IS programs offer each of the seven core courses in IS 2010. Moreover, these core courses were examined from three different perspectives: school type, accreditation, and research orientation.

Recognition of sweet, bitter and umami tastes requires the nonvesicular release from taste bud cells of ATP, which acts as a neurotransmitter to activate afferent neural gustatory pathways (1). However, how ATP is released to fulfil this function is not fully understood. Here we show that calcium homeostasis modulator 1 (CALHM1), a voltage-gated ion channel (2,3), is indispensable for taste-stimuli-evoked ATP release from sweet-, bitter- and umami-sensing taste bud cells. Calhm1 knockout mice have severely impaired perceptions of sweet, bitter and umami compounds, whereas their recognition of sour and salty tastes remains mostly normal. Calhm1 deficiency affects taste perception without interfering with taste cell development or integrity. CALHM1 is expressed specifically in sweet/bitter/umami-sensing type II taste bud cells. Its heterologous expression induces a novel ATP permeability that releases ATP from cells in response to manipulations that activate the CALHM1 ion channel. Knockout of Calhm1 strongly reduces voltage-gated currents in type II cells and taste-evoked ATP release from taste buds without affecting the excitability of taste cells by taste stimuli. Thus, CALHM1 is a voltage-gated ATP-release channel required for sweet, bitter and umami taste perception., Tastes are sensed by dedicated receptor cells in taste buds, which are composed of three anatomically distinct types of cells: types I, II and III. Only type III cells, which [...]

Effects of biochar amendment on plant physiological characteristics and sulfur bioavailability of light sierozem soil is not well-known. In this study, the effects of biochars produced from maize stalks at 300 and 600°C, named as BMS300 and BMS600, on maize physiological characteristics and sulfur bioavailability in the soil were investigated. Biochars were systematically characterized and evaluated, by means of EA, BET, SEM, FTIR and XRD. Through the pot experiments, the amounts of exogenous sulfur were applied as 0, 50, and 100 mgS/kg soil, named as BMS300+L, BMS300+H, BMS600+Land BMS600+H. Application rates of biochars were applied as 0, 7, 14, 21, and 28 gC/kg soil, and named as B0, Bl, B2, B3 and B4 respectively. The results showed that the biochar rates increased significantly (P < 0.05); it also induced the increase in physiological characteristics of maize growth under the 50 mg S/kg sulfur concentration, when the biochar at BMS600+L and the rates were applied to Bl, B2 and B3, the height of maize reached the highest rate as 94, 103 and 111 cm, respectively, whereas the lowest height was observed in B4. The fresh and dry weight of maize increased gradually when the rates of biochar were applied to Bl, B2 and B3, fresh weight reached 235, 263 and 275 g, and dry weight was 64, 75 and 78 g respectively. The soil pH value increased with the increase in amount of biochar, when the biochar was B4, the greater pH value was recorded in BMS600+L & BMS600+H samples and was increased to 8.2 and 8.6% respectively. Two types of soil enzyme activity increased with the increase of biochar, and reached significance (P < 0.05). Total sulfur content in soil showed the highest values in BMS600+L, when the amount of biochar was applied to B2, B3, and B4. The content of sulfur was increased and then decreased to 216.45, 240.17 and 234.46 mg/kg soil. The effects of biochar on development of plant growth, nutrient quality and availability of sulfur, could provide the scientific reference for the biochar application, in addition, to control sulfur fertilizers utilization, high quality and yield of crops in farmland soil. [ABSTRACT FROM AUTHOR]

Copper is an essential trace element that may serve as a signaling molecule in the nervous system. Here we show that extracellular [Cu.sup.2+] is a potent inhibitor of BK and Shaker [K.sup.+] channels. At low micromolar concentrations, [Cu.sup.2+] rapidly and reversibly reduces macrosocopic [K.sup.+] conductance ([G.sub.K]) evoked from mSlo1 BK channels by membrane depolarization. [G.sub.K] is reduced in a dose-dependent manner with an [IC.sub.50] and Hill coefficient of ~2 [micro]M and 1.0, respectively. Saturating 100 [micro]M [Cu.sup.2+] shifts the [G.sub.K]-V relation by +74 mV and reduces [G.sub.Kmax] by 27% without affecting single channel conductance. However, 100 [micro]M [Cu.sup.2+] fails to inhibit [G.sub.K] when applied during membrane depolarization, suggesting that [Cu.sup.2+] interacts poorly with the activated channel. Of other transition metal ions tested, only [Zn.sup.2-] and [Cd.sup.2+] had significant effects at 100 DM with [IC.sub.50]s > 0.5 mM, suggesting the binding site is [Cu.sup.2+] selective. Mutation of external Cys or His residues did not alter [Cu.sup.2+] sensitivity. However, four putative [Cu.sup.2+]-coordinating residues were identified (D133, Q151, D153, and R207) in transmembrane segments S1, $2, and $4 of the mSlo1 voltage sensor, based on the ability of substitutions at these positions to alter [Cu.sup.2+] and/or [Cd.sup.2+] sensitivity. Consistent with the presence of acidic residues in the binding site, [Cu.sup.2+] sensitivity was reduced at low extracellular pH. The three charged positions in S1, $2, and $4 are highly conserved among voltage-gated channels and could play a general role in metal sensitivity. We demonstrate that Shaker, like mSlo1, is much more sensitive to [Cu.sup.2+] than [Zn.sup.2+] and that sensitivity to these metals is altered by mutating the conserved positions in S1 or $4 or reducing pH. Our results suggest that the voltage sensor forms a state- and pH-dependent, metal-selective binding pocket that may be occupied by [Cu.sup.2+] at physiologically relevant concentrations to inhibit activation of BK and other channels.

BK (Slol) potassium channels arc activated by millimolar intracellular [Mg.sup.2+] as well as micromolar [Ca.sup.2+] and membrane depolarization. [Mg.sup.2+] and [Ca.sup.2+] act ill all approximately additive manner m different binding sites to shift t conductance-voltage ([G.sub.K]-V) relation, suggesting that these ligands might work through functionally similar but independent mechanisms. However, we lind that the mechanism of [Mg.sup.2+] action is highly dependent on voltage sensor activation and therefore differs fundamentally from that of [Ca.sup.2+]. Evidence that [Ca.sup.2+] acts independently of voltage sensor activation includes an ability to increase open probability ([P.sub.o]) at extreme negative voltages where voltage sensors are in the resting state; 2 [micro]M [Ca.sup.2+] increases [P.sub.o] more than 15-fold at -120 mV. However 10 mM [Mg.sup.2+] which has an effect on the [G.sub.K]-V relation similar to 2 [micro]M [Ca.sup.2+], has no detectable effect on [P.sub.o] when voltage sensors are in the resting state. Gating currents are only slightly altered by [Mg.sup.2+] when channels are closed, indicating that [Mg.sup.2+] does not act merely to promote voltage sensor activation. Indeed, channel opening is facilitated in a voltage-independent manner by [Mg.sup.2+] in a mutam (R210C) whose voltage sensors are constitutively activated. Thus, 10 mM [Mg.sup.2+] increases [P.sub.o] only when voltage sensors are activated, effectively strengthening the allosteric coupling of voltage sensor activation to channel opening. Increasing [Mg.sup.2+] from 10 to 100 mM, to occupy very low affinity binding sites, has additional effects on gating that more closely resemble those of [Ca.sup.2+]. The effects of [Mg.sup.2+] on steady-state activation and [I.sub.K] kinetics are discussed in terms of an allosteric gating scheme and the state-dependent interactions between [Mg.sup.2+] and voltage sensor that may underlie this mechanism.

Web search engines typically provide search results without considering user interests or context. We propose a personalized search approach that can easily extend a conventional search engine on the client side. Our mapping framework automatically maps a set of known user interests onto a group of categories in the Open Directory Project (ODP) and takes advantage of manually edited data available in ODP for training text classifiers that correspond to, and therefore categorize and personalize search results according to user interests. In two sets of controlled experiments, we compare our personalized categorization system (PCAT) with a list interface system (LIST) that mimics a typical search engine and with a nonpersonalized categorization system (CAT). In both experiments, we analyze system performances on the basis of the type of task and query length. We find that PCAT is preferable to LIST for information gathering types of tasks and for searches with short queries, and PCAT outperforms CAT in both information gathering and finding types of tasks, and for searches associated with free-form queries. From the subjects' answers to a questionnaire, we find that PCAT is perceived as a system that can find relevant Web pages quicker and easier than LIST and CAT. General Terms: Algorithms, Performance Additional Key Words and Phrases: Personalized search, user interest, user interface, World Wide Web, information retrieval, Open Directory DOI = 10.1145/1198296.1198301

The activation of large conductance [Ca.sup.2+]-activated (BK) potassium channels is weakly voltage dependent compared to Shaker and other voltage-gated [K.sup.+] ([K.sub.v]) channels. Yet BK and Kv channels share many conserved charged residues in transmembrane segments S1-S4. We mutated these residues individually in mS1o1 BK channels to determine their role in voltage gating, and characterized the voltage dependence of steady-state activation ([P.sub.o]) and [I.sub.K] kinetics ([tau] ([I.sub.K])) over an extended voltage range in 0-50 [micro]M [[Ca.sub.2+].sub.i]. mS1o1 contains several positively charged arginines in S4, but only one (R213) together with residues in S2 (D153, R167) and S3 (D186) are potentially voltage sensing based on the ability of charge-altering mutations to reduce the maximal voltage dependence of [P.sup.o]. The voltage dependence of [P.sub.o] and [tau]([I.sub.K]) at extreme negative potentials was also reduced, implying that the closed-open conformational change and voltage sensor activation share a common source of gating charge. Although the position of charged residues in the BK and [K.sub.v] channel sequence appears conserved, the distribution of voltage-sensing residues is not. Thus the weak voltage dependence of BK channel activation does not merely reflect a lack of charge but likely differences with respect to [K.sub.v] channels in the position and movement of charged residues within the electric field. Although mutation of most sites in S1-S4 did not reduce gating charge, they often altered the equilibrium constant for voltage sensor activation. In particular, neutralization of R207 or R210 in S4 stabilizes the activated state by 3-7 kcal mol- 1, indicating a strong contribution of non-voltage-sensing residues to channel function, consistent with their participation in state-dependent salt bridge interactions. Mutations in S4 and S3 (R210E, D186A, and E180A) also unexpectedly weakened the allosteric coupling of voltage sensor activation to channel opening. The implications of our findings for BK channel voltage gating and general mechanisms of voltage sensor activation are discussed.

The S4 transmembrane segment is the primary voltage sensor in voltage-dependent ion channels. Its movement in response to changes in membrane potential leads to the opening of the activation gate, which is formed by a separate structural component, the S6 segment. Here we show in voltage-, C[a.sup.2+-], and M[g.sup.2+]-dependent, large conductance [K.sup.+] channels that the S4 segment participates not only in voltage- but also M[g.sup.2+]-dependent activation. Mutations in S4 and the S4-S5 linker alter voltage-dependent activation and have little or no effect on activation by micromolar C[a.sup.2+]. However, a subset of these mutations in the C-terminal half of S4 and in the S4-S5 linker either reduce or abolish the M[g.sup.2+] sensitivity of channel gating. Cysteine residues substituted into positions R210 and R213, marking the boundary between S4 mutations that alter M[g.sup.2+] sensitivity and those that do not, are accessible to a modifying reagent [sodium (2-sulfonatoethyl)methane-thiosulfonate] (MTSES) from the extracellular and intracellular side of the membrane, respectively, at -80 mV. This implies that interactions between Sa, and a cytoplasmic domain may be involved in M[g.sup.2+]-dependent activation. These results indicate that the voltage sensor is critical for M[g.sup.2+]-dependent activation and the coupling between the voltage sensor and channel gate is a converging point for voltage- and M[g.sup.2+]-dependent activation pathways.

Objective: To comprehensively investigate the effects of 25 variants in 15 genes on dental caries susceptibility in a cohort of Chinese children. Methods: A total of 25 variants in 15 genes were genotyped with MassARRAY iPLEX system and analyzed in 265 healthy controls and 254 children affected by dental caries with different dmft scores. The children with dental caries were stratified into "mild group" (scores from 1 to 3), "moderate group" (scores from 4 to 6), and "severe group" (scores from 7 to 14). Results: The association analysis revealed that rs11362 of defensin β1 (DEFB1) was significantly associated with dental caries susceptibility (OR = 2.447, p = 1.165E−04). Furthermore, rs11362 was positively correlated with the severity of dental caries. For another selected variant of DEFB1, rs1799946 was significantly associated with dental caries susceptibility in the severe group (OR = 0.473, p = 3.70E−03) and also significant in the group consisted of moderate and severe subjects (OR = 0.623, p =.033). The results from logistic regression in additive, dominant, and recessive models also exhibited the similar patterns. Conclusion: Out of 25 selected variants, only 2 of DEFB1 gene (rs11362 and rs1799946) were significantly associated with dental caries susceptibility in children. [ABSTRACT FROM AUTHOR]