A monokultúra és a vetésváltás hatásának vizsgálata a kukoricatermesztésben = Examining the effect of crop rotation and monoculture in maize production

A vetésváltásban termesztett kukorica egyértelműen, szignifikánsan több termést ad. Öntözött körülmények között a nem trágyázott parcellákon a vetésváltás termésnövelő hatása 55%-os. Trágyázás nélkül az elmúlt négy év (2003-2006) átlagában az öntözés csökkentette a kukorica termését! Amennyiben az öntözést műtrágyázással kombináljuk a vetésváltás termésnövelő hatása mérséklődik, értéke 8-10% körül alakul. Kedvező víz- és tápanyag-ellátottság esetén némelyik évben teljesen el is tűnik a vetésváltás kedvező hatása. A vetésváltásban kevesebb a talaj könnyen oldható nitrát tartalma, mint a monokultúrában. A trágyázás egyértelműen növeli a talaj nitrát és nitrit tartalmát. Vetésváltásban a nem trágyázott parcellákon alacsony, 5-7 ppm, a 120 N kg/ha parcellákon közel háromszor ennyi, 17-21 ppm a nitrát és nitrit tartalom. Öntözött körülmények között a vetésváltás nem befolyásolja a talaj nitrát-nitrit tartalmát, mert az öntözés nitrogén kilúgzó hatása mindkét kezelésben erősen jelentkezik. Az elvégzett vizsgálatok alapján az öntözött ill. öntözés nélküli körülmények között a talaj humusztartalmát sem a vetésváltás, sem a trágyázás nem befolyásolta szignifikánsan. A vetésváltás termésnövelő hatása egyértelműen a forgatást alkalmazó talajművelés esetén nagyobb. Ebben az esetben megközelíti a 30%-ot. Forgatásnélküli talajművelés esetében ez a hatás 13%-ra mérséklődik. Ezt érdemes figyelembe venni napjaink modern talajművelési rendszereiben, ahol sok esetben a forgatás mellőzik. | The maize produced in a rotation cycle gives expressly and significantly more yield. Under irrigated conditions the yield-increasing impact of the rotation cycle is of 55% on non-fertilised parcels. Under non-fertilised conditions the yield of maize was decreased by irrigation in the average of the last four years. In case we combine irrigation with fertilisation, the yield-increasing impact of rotation cycle is moderating, its value is about 8-10%. Under favourable water- and nutritive supply conditions, the favourable impact of rotation cycle completely disappears in certain years. The soluble nitrate content of the soil is less in rotation cycle than that in monoculture. Fertilisation increases the nitrate and nitrite content of the soil expressly. The nitrate-nitrite content in rotation cycle on non-fertilised parcels is low, about 5-7 ppm, while on parcels fertilised with 120 N kg/ha it is almost three times as much, that is 17-21 ppm. Under irrigated conditions rotation cycle does not affect the nitrate-nitrite content of the soil. The N leaching impact of irrigation is strongly present in both treatments. The yield-increasing impact of the rotation cycle is clearly stronger when the soil is tilled-up. In this case it is almost 30%, while in case of conservation tillage the impact reduces to 13%. This is worth considering in nowadays modern cultivation systems, where tillage is neglected in many cases

Halfspace depth for general measures: The ray basis theorem and its consequences

The halfspace depth is a prominent tool of nonparametric multivariate analysis. The upper level sets of the depth, termed the trimmed regions of a measure, serve as a natural generalization of the quantiles and inter-quantile regions to higher-dimensional spaces. The smallest non-empty trimmed region, coined the halfspace median of a measure, generalizes the median. We focus on the (inverse) ray basis theorem for the halfspace depth, a crucial theoretical result that characterizes the halfspace median by a covering property. First, a novel elementary proof of that statement is provided, under minimal assumptions on the underlying measure. The proof applies not only to the median, but also to other trimmed regions. Motivated by the technical development of the amended ray basis theorem, we specify connections between the trimmed regions, floating bodies, and additional equi-affine convex sets related to the depth. As a consequence, minimal conditions for the strict monotonicity of the depth are obtained. Applications to the computation of the depth and robust estimation are outlined

PREPARATION AND INVESTIGATION OF TRIALKOXY-SILYL DERIVATIVES OF SATURATED CARBOXYLIC ACIDS

A study was carried out on the preparation of triethoxy-silyl derivatives of the allyl esters of several carboxylic acids. This has been achieved by the preparation of the allyl esters of carboxylic acids followed by the addition of triethoxy-silane, HSi(OCH₂ CH₃)₃ on the double bond of the allyl group. The new compounds were characterized by refractivity, density, boiling point, elemental analysis, lR and 1H-NMR spectroscopy methods

Another look at halfspace depth: Flag halfspaces with applications

The halfspace depth is a well studied tool of nonparametric statistics in multivariate spaces, naturally inducing a multivariate generalisation of quantiles. The halfspace depth of a point with respect to a measure is defined as the infimum mass of closed halfspaces that contain the given point. In general, a closed halfspace that attains that infimum does not have to exist. We introduce a flag halfspace - an intermediary between a closed halfspace and its interior. We demonstrate that the halfspace depth can be equivalently formulated also in terms of flag halfspaces, and that there always exists a flag halfspace whose boundary passes through any given point $x$, and has mass exactly equal to the halfspace depth of $x$. Flag halfspaces allow us to derive theoretical results regarding the halfspace depth without the need to differentiate absolutely continuous measures from measures containing atoms, as was frequently done previously. The notion of flag halfspaces is used to state results on the dimensionality of the halfspace median set for random samples. We prove that under mild conditions, the dimension of the sample halfspace median set of $d$-variate data cannot be $d-1$, and that for $d=2$ the sample halfspace median set must be either a two-dimensional convex polygon, or a data point. The latter result guarantees that the computational algorithm for the sample halfspace median form the R package TukeyRegion is exact also in the case when the median set is less-than-full-dimensional in dimension $d=2$

Early-stage entrepreneurial aspirations in efficiency-driven economies

The aim of this article is to identify the influencing factors of early-stage entrepreneurial aspirations in efficiency-driven economies based on Global Entrepreneurship Monitor (GEM) Adult Population Survey (APS) database for the year 2008. Within the entrepreneurial aspirations the innovativeness of entrepreneurial businesses and the job growth expectations were studied.early-stage entrepreneur, entrepreneurial aspirations, Global Entrepreneurship Monitor.

An empirical investigation of the benefit of increasing the temporal resolution of task-evoked fMRI data with multi-band imaging

Objective There is a tendency for reducing TR in MRI experiments with multi-band imaging. We empirically investigate its benefit for the group-level statistical outcome in task-evoked fMRI. Methods Three visual fMRI data sets were collected from 17 healthy adult participants. Multi-band acquisition helped vary the TR (2000/1000/410 ms, respectively). Because these data sets capture different temporal aspects of the haemodynamic response (HRF), we tested several HRF models. We computed a composite descriptive statistic, H, from β’s of each first-level model fit and carried it to the group-level analysis. The number of activated voxels and the t value of the group-level analysis as well as a goodness-of-fit measure were used as surrogate markers of data quality for comparison. Results Increasing the temporal sampling rate did not provide a universal improvement in the group-level statistical outcome. Rather, both the voxel-wise and ROI-averaged group-level results varied widely with anatomical location, choice of HRF and the setting of the TR. Correspondingly, the goodness-of-fit of HRFs became worse with increasing the sampling frequency. Conclusion Rather than universally increasing the temporal sampling rate in cognitive fMRI experiments, these results advocate the performance of a pilot study for the specific ROIs of interest to identify the appropriate temporal sampling rate for the acquisition and the correspondingly suitable HRF for the analysis of the data