Risk Indicators for Tooth Loss Due to Periodontal Disease

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142117/1/jper1910.pd

Oral health knowledge and behavior among male health sciences college students in Kuwait

BACKGROUND: Health auxiliary personnel have an important role in oral health promotion when they graduate and start working in the health care system. This study aims to find out oral health knowledge and oral health behavior of male Health Sciences College students. METHODS: A questionnaire was distributed to all students at the male Health Sciences College in Kuwait (N = 153) during the academic year 2001/2002. The students filled the anonymous questionnaire in the class after the lecture. The response rate was 84% (n = 128). The questions consisted information on the general background, oral health behavior and oral health knowledge. RESULTS: Oral health knowledge seemed to be limited and very few background factors were associated with it. More than half of the students had visited a dentist during the previous 12 months, but only one third of students were brushing twice a day or more often. CONCLUSIONS: It may be concluded that the male Health Sciences College students seemed to have appropriate knowledge on some oral health topics, but limited knowledge on the others. Their toothbrushing practices are still far behind the international recommendation (twice a day) and also the knowledge, why it should be done so frequently also very limited

Physical drivers of chlorophyll and nutrients variability in the Southern-Central Arabian Gulf

The southern-central Arabian Gulf demonstrates a poor understanding of nutrients and chlorophyll dynamics in physical-biogeochemical settings. Here, using data of chlorophyll, nutrients and hydrographic parameters collected in two cruises in summer 2019 and winter 2020, we examined variability in nutrients and chlorophyll concentrations, and the driving mechanisms. Summer thermal stratification enhanced by intrusion of fresher surface water plume from the Arabian Sea developed a hypoxic zone (DO 3) was about 1.4 times the winter concentration (mean = 0.58 mg/m3) (p > 0.05). Photo-protective carotenoids content in summer (0.59 mg/m3) was about 2.7 times their winter concentration. Winter cooling resulted in downwelling of dense water on the shallow coastal banks, which enhanced near bottom oxygen concentrations and swept away nutrient-rich water resulting in lower winter chlorophyll. This research features aspects of the physical and biogeochemical drivers underpinning the dynamics of nutrients and chlorophyll in the central Gulf.Other InformationPublished in: Estuarine, Coastal and Shelf ScienceLicense: http://creativecommons.org/licenses/by/4.0/See article on publisher's website: https://dx.doi.org/10.1016/j.ecss.2023.108260</p

Ocean Acidification and Carbonate System Geochemistry in the Arabian Gulf

Alkalinity (Alk) and (Dissolved Inorganic Carbon) DIC were measured on high resolution seawater samples, collected on November 2018 and May 2019 at seven stations in the Exclusive Economic Zone (EEZ) of Qatar. Calculated surface PCO2 averaged 472 matm in 2018 and 447 matm in 2019. Thus: the Arabian Gulf is degassing CO2 at present and will not take up atmospheric CO2 until 2042. Ocean acidification is not yet an issue in the EEZ of Qatar. The elevated PCO2 values are due to CaCO3 formation. Normalized NAlk and NDIC were calculated to remove the impact of increasing salinity. NAlk and NDIC decrease corresponding to a CaCO3/OrgC removal ratio of 2/1. We calculated the nitrate corrected and salinity normalized tracer, Alk*. Values of Alk* were negative, and the change in Alk* relative to Hormuz (DAlk*) indicated that there has been an average decrease of Alk* of -130 mmol kg-1. This decrease is due to CaCO3 formation but previous studies found no evidence for coccolithophorids. One obvious possibility is that Alk removal is due to CaCO3 formation in coral reefs. However, recent study of the composition of particulate matter found that the average particulate Ca concentration was 3.6%, and was easily acid soluble (Yigiterhan et al, 2018). These results suggest that a significant amount of particulate CaCO3 is present in the water column. One hypothesis is that the particulate Ca comes from carbonate rich atmospheric dust. Using Al as a tracer for dust and the average Ca/Al ratio in Qatari dust can only explain about 3% of the particulate Ca. An alternative hypothesis is that particulate CaCO3 may form in the water column due to abiological CaCO3 formation, as proposed recently for the Red Sea (Wurgaft et al., 2016). Precipitation of CaCO3 may be induced by the large inputs of nucleation sites in the form of atmospheric dust

Excess pCO2 and carbonate system geochemistry in surface seawater of the exclusive economic zone of Qatar (Arabian Gulf)

Dissolved inorganic carbon (DIC) and total alkalinity (TA) were sampled in December 2018 and May 2019 in the Exclusive Economic Zone (EEZ) of Qatar in the Arabian Gulf. pCO2, pH and CO32− were calculated from DIC and TA. TA, DIC and salinity increase in the Gulf due to evaporation after entering through the Strait of Hormuz. Temperature also increases. The pCO2 in surface seawater averaged 458 ± 62 which was higher than the atmospheric value of 412 ppm. Hence, the Gulf was a source of CO2 to the atmosphere. pCO2 in seawater is controlled by TA relative to DIC as well as temperature and salinity. A hypothetical model calculation was used to estimate how much pCO2 could increase in surface seawater due to various processes after entering through the Strait of Hormuz. Increases in T and S, in the absence of biogeochemical processes, would increase pCO2 to 537 μatm, more than enough to explain the high pCO2 observed. CO2 is lost from the Gulf due to gas exchange, decreasing DIC, and reducing pCO2 to 464 μatm, similar to that observed. The impact of biological processes depends on the process: calcification increases pCO2 while net primary production decreases pCO2. Salinity-normalized (to S = 40) total alkalinity (NTA) and dissolved inorganic carbon (NDIC) in surface seawater decrease as waters flow north from Hormuz. The slope suggests that removal of C as CaCO3, organic matter (CH2O) or gas exchange (FCO2) is occurring with a ratio of ΔCaCO3/(ΔCH2O or FCO2) = 1:2.86. The tracer Alk*, defined as the deviation of potential alkalinity (AP) (where AP = TA + 1.26 [NO3]) from conservative potential alkalinity ((ApC), (ApC = S Ap′S′ where A'P and S′ are mean values for the whole surface ocean) has values primarily determined by CaCO3 precipitation and dissolution. Its values in the Gulf ranged from −50 to −310 μmol kg−1 implying CaCO3 precipitation. The average value of ΔAlk*, the difference in Alk* between specific locations in the Qatari EEZ and the surface water entering through the Strait of Hormuz, was −130 μmol kg−1 which corresponded to a calcification of 65 μmol kg−1. Our model calculations indicate that this would increase pCO2 to 577 μatm. Carbonate forming plankton have not been observed in the water column suggesting that calcification occurs in corals, even though they have been severely damaged by past bleaching events. The amount of DIC removed by net primary production is small, consistent with an oligotrophic food web dominated by remineralization. It appears that the role of biological production in the water column for the control of pCO2 is very small. The high observed pCO2 reflects a balance between sources due to the impact of increasing T and S on the carbonate system equilibrium constants and net calcification and sinks due to CO2 loss due to gas exchange and net primary production in surface seawater after it enters the Gulf through the Strait of Hormuz