Mediterranean climate river systems are among the most threatened ecosystems worldwide, due to a long history of anthropogenic impacts and alien invasive species introductions. Many of such rivers ...naturally exhibit a non-perennial flow regime, with distinct seasonal, inter-annual and spatial heterogeneity. The present study seeks to detect diatom community patterns and to understand the processes that cause these structures in an Austral Mediterranean river system among different months and river sections. In general, most environmental variables showed an increasing trend downstream for both months, with the exception of pH, dissolved oxygen, PO₄3− and substrate embeddedness, which decreased downstream. A total of 110 diatom species between the two study months (October – 106 taxa; January – 78 taxa) were identified, dominated by 30 species with at least >2% abundance. Diatom community structure differed significantly across river zones, while no significant differences were observed between the study months. A boosted regression trees model showed that B (43.3%), Cu (20.8%), Fe (3.4%) and water depth (3.2%) were the most significant variables structuring diatoms. Diatom species communities reflected environmental variables (i.e., sediment and water chemistry) in this Mediterranean climate river system, as sediment metals such as B, Cu and Fe were found to be important in structuring diatom communities. Biotic influences from fish communities had little effect on diversity, but shifted diatom community structure. Therefore, the current study highlights how river systems have complex interactions that play an important role in determining diatom species composition.
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•Sediment and water chemistry variables increased downstream in both events.•110 diatom species across the two study events identified.•Significant differences observed in diatom community across river zones and events.•Boron and copper most important variables in structuring diatoms.
In this work, gelatin (G)-polyacrylamide (PAAm)-based interpenetrating polymer network (IPN) hydrogels involving maleic acid (MA) was prepared using by radical polymerization. Full-IPN and semi-IPN ...hydrogels were synthesized by using glutaraldehyde and ethylene glycol dimethacrylate (EGDMA) as a crosslinker. The water absorbency of hydrogels was investigated, and the values increased with MA and G. The chemical structures of full-IPN and semi-IPN hydrogels were tested by Fourier Transform Infrared Spectroscopy (FTIR). Morphological test was done by using Scanning Electron Microscope/ Energy Dispersive X-ray Spectroscopy (SEM/EDX). Thermal properties were examined with Differential scanning calorimeter (DSC) analyzer and Thermogravimetric analysis (TGA). The mechanical analysis was performed with Zwick Universal Testing Machine. Thermal and mechanical stabilities of full-IPN hydrogel was higher than semi-IPN. The efficiency of adsorption parameters (contact time, initial feed concentration, and pH) on Chromium (VI) ion adsorbing property of Full-IPN hydrogel was also determined. Isotherms were explained with the Langmuir or Freundlich equations. According to the results of both isotherms, it can be said that the hydrogel surface was homogeneous, and the adsorption of Chromium (VI) occurred in a monolayer.
Bu çalışmada, jelatin (G) -poliakrilamid (PAAm) bazlı, maleik asit (MA) içeren iç içe geçen polimer ağı (IPN) hidrojelleri, radikal polimerizasyon kullanılarak hazırlanmıştır. Tam-IPN ve yarı-IPN hidrojeller, çapraz bağlayıcı olarak glutaraldehit ve etilen glikol dimetakrilat (EGDMA) kullanılarak sentezlendi. Hidrojellerin su emiciliği incelendi ve değerler MA ve G ile arttı. Tam IPN ve yarı IPN hidrojellerin kimyasal yapıları Fourier Dönüşümü Kızılötesi Spektroskopisi (FTIR) ile test edildi. Taramalı Elektron Mikroskobu/ Enerji Dağılımlı X-ışını Spektroskopisi (SEM/EDX) kullanılarak morfolojik test yapıldı. Termal özellikler Diferansiyel taramalı kalorimetre (DSC) analizörü ve Termogravimetrik analiz (TGA) ile incelenmiştir. Mekanik analiz, Zwick Universal Test Makinesi ile yapıldı. Tam IPN hidrojelin termal ve mekanik stabiliteleri yarı IPN'den daha yüksekti. Tam-IPN hidrojelinin Krom (VI) iyonu adsorbe etme özelliği üzerindeki adsorpsiyon parametrelerinin (temas süresi, başlangıç besleme konsantrasyonu ve pH) etkinliği de belirlendi. İzotermler Langmuir veya Freundlich denklemleriyle açıklandı. Her iki izotermin sonucuna göre, hidrojel yüzeyinin homojen olduğu ve Krom (VI) adsorpsiyonunun bir tek tabakada meydana geldiği söylenebilir.
We study the expressive power and complexity of second-order revised Krom
logic (SO-KROM$^{r}$). On ordered finite structures, we show that its
existential fragment $\Sigma^1_1$-KROM$^r$ equals ...$\Sigma^1_1$-KROM, and
captures NL. On all finite structures, for $k\geq 1$, we show that
$\Sigma^1_{k}$ equals $\Sigma^1_{k+1}$-KROM$^r$ if $k$ is even, and $\Pi^1_{k}$
equals $\Pi^1_{k+1}$-KROM$^r$ if $k$ is odd. The result gives an alternative
logic to capture the polynomial hierarchy. We also introduce an extended
version of second-order Krom logic (SO-EKROM). On ordered finite structures, we
prove that SO-EKROM collapses to $\Pi^{1}_{2}$-EKROM and equals $\Pi^1_1$. Both
SO-EKROM and $\Pi^{1}_{2}$-EKROM capture co-NP on ordered finite structures.
Svrha: Iz postojeće literature poznato je da metalni ioni iz ortodontskih naprava mogu korodirati zbog djelovanja sline i bakterija u usnoj šupljini. Rezultati većine studija upućuju na to da se ...razina nikla i kroma u slini ne povisuje nakon postavljanja ortodontskih naprava. No nema istraživanja o razini titanija, kobalta, bakra i cinka u slini ortodontskih pacijenata. Ispitanici i postupci: Razina nikla (Ni), titanija (Ti), kroma (Cr), kobalta (Co), bakra (Cu) i cinka (Zn) mjerena je u slini četrdeset i dvoje pacijenta s keramičkim metalnim bravicama i isto toliko njih s konvencionalnima i to prije postavljanja ortodontskih naprava s pomoću induktivne spregnute plazme/masene spektrometrije i šest mjeseci poslije toga. U statističkoj analizi korištena su dva testa – Wilcoxonov signed rank i Mann-Whitneyev s razinom značajnosti od 0,05. Rezultati: Rezultati su pokazali da se razina titana u slini povisila šest mjeseci nakon postavljanja ortodontskih naprava. Razina kroma i cinka, pak, značajno se snizila nakon postavljanja ortodonskih naprava. Nije bilo statistički značajne razlike u razini nikla, titanija, kroma, bakra, kobalta i cinka u slini između pacijenata s metalnim i keramičkim ortotontskim
bravicama. Zaključak: Možemo zaključiti da se razina titanija u slini značajno povisila šest mjeseci nakon postavljanja ortodontskih naprava za razliku od razine kroma i cinka koja se značajno snizila šest mjeseci poslije njihova postavljanja, bez obzira na vrstu korištenih bravica.
Distributions of arsenic and metals in surface sediments collected from the coastal and estuarine areas of the northern Bohai and Yellow Seas, China, were investigated. An ecological risk assessment ...of arsenic and metals in the sediments was evaluated by three approaches: the Sediment Quality Guidelines (SQGs) of the United States Environmental Protection Agency (USEPA), the degree of contamination, and two sets of SQGs indices. Sediments from the estuaries of the Wuli and Yalu Rivers contained some of the greatest concentrations of arsenic, cadmium, copper, mercury, lead, and zinc. Median concentrations of cadmium and mean concentrations of lead and zinc were greater than background concentrations determined for the areas. All sediments were considered to be heavily polluted by arsenic, but moderately polluted by chromium, lead, and cadmium. Current concentrations of arsenic and metals are unlikely to be acutely toxic, but chronic exposures would be expected to cause adverse effects on benthic invertebrates at 31.4% of the sites.
This qualitative investigation explores the role of dance in maintaining spiritual identity in the context of popular culture. The focus of the investigation is the Fon Buang Suang dance of Udon ...Thani. Drawing on the documentary review and field data gathered from observations and interviews, this article examines how the use of traditional and contemporary dance elements in Fon Buang Suang reflects a cultural shift toward modernity, while still maintaining spiritual and ritualistic elements. This article argues that this dance, along with other examples of ritualistic dance in the region, serves as important markers of cultural identity and helps to maintain a sense of spiritual continuity in a rapidly changing world. Overall, this investigation contributes to the growing body of research on the role of dance in popular culture and its impact on the preservation of traditional cultural and religious practices.
More on products of Baire spaces Li, Rui; Zsilinszky, László
Topology and its applications,
10/2017, Volume:
230
Journal Article
Peer reviewed
Open access
New results on the Baire product problem are presented. It is shown that an arbitrary product of almost locally ccc Baire spaces is Baire; moreover, the product of a Baire space and a 1st countable ...space which is β-unfavorable in the strong Choquet game is Baire.
In this paper, we report on synthesizing xonotlite, calcium silicate hydrate (CSH), via a hydrothermal reaction using rice husk from the Mekong Delta, Vietnam. The rice husks were burnt at 1000 °C ...for 3 h. Grey rice husk ash was collected, then mixed with Ca(OH)2 at a Ca/Si molar ratio of 1 : 1. This was followed by a hydrothermal reaction at 180 °C for 24 h and 48 h to obtain the xonotlite mineral. Before and after adsorption, 3-mm xonotlite pellets were thoroughly characterized using X-ray diffractometry (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and ultraviolet-visible (UV-VIS) spectroscopy. This material has potential application in chromium(III) removal during a chrome-plating process. The adsorption efficiency of the 3-mm pellet samples reached more than 76 % after 12 h.
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