298 research outputs found
Consecutive patterns in restricted permutations and involutions
It is well-known that the set of involutions of the symmetric
group corresponds bijectively - by the Foata map - to the set
of -permutations that avoid the two vincular patterns
We consider a bijection from the set
to the set of histoires de Laguerre, namely, bicolored Motzkin paths with
labelled steps, and study its properties when restricted to In particular, we show that the set
of permutations that avoids the
consecutive pattern and the classical pattern
corresponds via to the set of Motzkin paths, while its image under
is the set of restricted involutions We exploit these
results to determine the joint distribution of the statistics des and inv over
and over
Moreover, we determine the distribution in these two sets of every
consecutive pattern of length three. To this aim, we use a modified version of
the well-known Goulden-Jacson cluster method.Comment: 24 page
Derivation of Land Surface Temperature from MODIS Data Using the General Split Window Technique
Fast Atmospheric Signature Code (FASCODE), a line-by-line radiative transfer programme, was used to simulate Moderate Resolution Imaging Spectroradiometer (MODIS) data at wavelengths 11.03 and 12.02 mm to ascertain how accurately the land surface temperature (LST) can be inferred, by the split window technique (SWT), for a wide range of atmospheric and terrestrial conditions. The approach starts from the Ulivieri algorithm, originally applied to Advanced Very High Resolution Radiometer (AVHRR) channels 4 and 5. This algorithm proved to be very accurate compared to several others and takes into account the atmospheric effects, in particular the water vapour column (WVC) amount and a non-unitary surface emissivity. Extended simulations allowed the determination of new coefficients of this algorithm appropriate to MODIS bands 31 and 32, using different atmospheric conditions. The algorithm was also improved by removing some of the hypothesis on which its original expression was based. This led to the addition of a new corrective term that took into account the interdependence between water vapour and non-unitary emissivity values and their effects on the retrieved surface temperature. The LST products were validated within 1K with in situ LSTs in 11 cases
Effect of Water Regime, Nitrogen Level, and Biostimulant Application on the Water and Nitrogen Use Efficiency of Wild Rocket [Diplotaxis tenuifolia (L.) DC]
The use of biostimulants in agriculture is an emerging technique that can contribute to improved production and resource use efficiency. This research was carried out in southern Italy to evaluate the biostimulating effects of seaweed extract (SW) and azoxystrobin (AZ) on wild rocket subjected to two water regimes (WRs) and three nitrogen levels (NLs), and grown in pots under unheated greenhouse conditions. The following treatments were compared: (i) two WRs: restoration of 100% (WR100) and 50% (WR50) of crop evapotranspiration; (ii) three NLs: 0 (N0), 75 (N75), or 150 (N150) kg ha−1 of N; and (iii) three biostimulants (BSs): an untreated control (C), and the application of AZ or SW. This paper reports the effects on N uptake (Nup), N use efficiency (NUE), and water use efficiency (WUE). The following indicators of NUE were assessed: apparent recovery efficiency (RE), internal utilization efficiency (IE), partial productivity factor (PFPn) of N supplied, agronomic efficiency (AE), and physiological efficiency (PE). The following indicators of WUE were assessed: photosynthetic WUE (p_WUE), yield WUE (Y_WUE), biomass WUE (B_WUE), and irrigation yield WUE (IY_WUE). The indicators of NUE were affected differently by treatments. RE was 20% higher with SW. IE was higher with AZ. PFPn increased by 10.4 and 8.1% with AZ and SW, respectively. AE increased by 10.9 and 19.9% after applying AZ and SW, respectively. PE rose by 6.7 and 9.3% after applying AZ and SW. AZ and SW improved p_WUE, mainly under water deficit (interaction of WR × BS). With AZ application, Y_WUE, B_WUE, and IY_WUE were higher by 17.8, 13.8, and 19.3%, respectively, while the application of SW resulted in a smaller increase (9.5–7.7 and 9.9%). SW and AZ were shown to be effective through the moderate improvement of wild rocket’s nitrogen and water use efficiency. The two biostimulants were more effective at improving p_WUE in water deficit conditions, proving to be particularly useful for farmers operating with water scarcity. Therefore, they can provide valuable support to farmers by improving the sustainability of resource use
Comparison of Bioactive Substances Content between Commercial and Wild-Type Isolates of Pleurotus eryngii
Mushrooms belonging to Pleurotus genus have been demonstrated to have important
nutritional and medicinal value and their regular intake prevent many diseases, reduce the infection
probability and increase immunity. In order to investigate the bioactive compounds produced
by seven commercial (‘142 F’, ‘142 E’, ‘D+’, ‘V turbo’, ‘V 142’, ‘A 12’, ‘V 160’) and five wild-type
(‘Albino 1107’, ‘Altamura 1603’, ‘Muro Lucano 139’, ‘Conversano 1250’, ‘Albino beige chiaro 1094’)
P. eryngii isolates, the following qualitative analyses were performed: Total polyphenol content,
antioxidant activity (EC50 of ABTS) and antiradical power (ARP) in fresh lyophilized and dry
basidioma, and water content, -glucans and phenolic compounds in fresh samples. Standard
methods were employed for each of the above mentioned aims. Total polyphenol content was diverse
among the P. eryngii isolates. In particular, an elevated polyphenolic content was found in fresh
lyophilized P. eryngii samples of the commercial isolates ‘V 142’ followed by ‘A 12’. The highest
antiradical activity (ARP) was obtained by ‘Muro Lucano 139’ isolate. Wild P. eryngii isolates were
characterized by higher water and -glucans contents compared to the commercial ones, and the
highest values were registered for the ‘Albino beige chiaro 1094’ isolate. In conclusion, the present
study allowed us to identify the commercial and wild-type P. eryngii isolates from the Basilicata
region, with high nutritional and medicinal value based on their bioactive compounds
Germano Sartelli
Libro-catalogo della mostra sugli artisti imolesi che hanno partecipato alle Biennali Internazionali d'arte di Venezia. Capitolo dedicato all'opera dello scultore Germano Sartelli, tra i principali esponenti dell'informale italiano
Effect of base–acid properties of the mixtures of water with methanol on the solution enthalpy of selected cyclic ethers in this mixture at 298.15 K
The enthalpies of solution of cyclic ethers: 1,4-
dioxane, 12-crown-4 and 18-crown-6 in the mixture of
water and methanol have been measured within the whole
mole fraction range at T = 298.15 K. Based on the obtained
data, the effect of base–acid properties of water–
methanol mixtures on the solution enthalpy of cyclic ethers
in these mixtures has been analyzed. The solution enthalpy
of cyclic ethers depends on acid properties of water–
methanol mixtures in the range of high and medium water
contents in the mixture. Based on the analysis performed, it
can be assumed that in the mixtures of high methanol
contents, cyclic ethe
Mission analysis for two potential asteroids threat scenarios: Optimal impact strategies and technology evaluation
The Space Mission Planning Advisory Group SMPAG's mission is to prepare for an international response to a Near Earth Object impact threat through the exchange of information, development of options for collaborative research and mission opportunities, and to conduct Near Earth Object (NEO) impact threat mitigation planning activities. This paper presents the preliminary work performed by the Italian Space Agency Delegation for defining few reference missions for different NEO-threat scenarios and carrying out Phase 0 studies. In this paper two scenarios are identified to study the possible response in case of a real NEO-threat. A direct and resonant impact scenario for an asteroid deflection mission are identified resembling to the asteroid 2010RF12 but with an increased asteroid mass. Then the mission analysis and spacecraft design for the direct impact case is performed and the results discussed
Standardizing Navigation Data: A Status Update
This paper presents the work of the Navigation Working Group of the Consultative Committee for Space Data Systems (CCSDS) on development of standards addressing the transfer of orbit, attitude and tracking data for space objects. Much progress has been made since the initial presentation of the standards in 2004, including the progression of the orbit data standard to an accepted standard, and the near completion of the attitude and tracking data standards. The orbit, attitude and tracking standards attempt to address predominant parameterizations for their respective data, and create a message format that enables communication of the data across space agencies and other entities. The messages detailed in each standard are built upon a keyword = value paradigm, where a fixed list of keywords is provided in the standard where users specify information about their data, and also use keywords to encapsulate their data. The paper presents a primer on the CCSDS standardization process to put in context the state of the message standards, and the parameterizations supported in each standard, then shows examples of these standards for orbit, attitude and tracking data. Finalization of the standards is expected by the end of calendar year 2007
Adaptive thrust vector control during on-orbit servicing
On-orbit servicing missions often include a final propulsive phase where a spacecraft pushes the other one towards a different orbit. Specifically this is the case of the debris grasping mission where the chaser, after capturing the target by means of robotic arms, has to perform a de-orbit operation. The large thrust involved needs a perfect alignment with respect to the center of mass or the system composed by chaser and target, in order to avoid attitude changes. Such accurate alignment is quite difficult to achieve especially when the characteristics of the target are not perfectly known. A procedure is proposed in this paper, allowing a complete estimation of the center of mass position and of the moments of inertia of the system, starting from the data obtained by the gyros mounted on board of the spacecraft. The output is used to design a maneuver for correcting the target and chaser relative position by moving the robotic arms. Numerical simulations show the proficiency and the applicability of the estimation algorithm and of re-alignment maneuver to a selected mission scenario
- …