Orbits Lightwave (United States)

Substance use among university undergraduates has become a growing public health concern, particularly in developing countries. Studies have shown that substance use in Lagos State has reached epidemic proportion with high prevalence among undergraduates. Despite numerous awareness campaigns, substance use remains prevalent among students in higher institutions. There is paucity of data on the comparative prevalence, pattern and knowledge of consequences of substance use among undergraduates. Hence, this study compared the prevalence, patterns and knowledge of consequences of substance use among undergraduates in selected universities in Lagos State, Nigeria. This study adopted cross-sectional research design. The population was 88,241 undergraduates from three universities (one Federal Owned University (FOU), one State Owned University (SOU) and One Privately Owned (PO)) in Lagos State, Nigeria. A sample size of 841 was determined using Cochran formula. A proportionate sampling technique was used to select respondents (FOU = 382, SOU = 294, and PO = 243). A structured and validated questionnaire with Cronbach’s alpha reliability coefficient ranging from 0.78 to 0.91 was used to collect data. The response rate was 80.8.%. Data were analysed using descriptive and inferential (t-test, multiple linear regression) statistics at 0.03% level of significance. Findings showed high prevalence rate of substance use among university students in FOU (60.10%), SOU (61.30%) and PO University (57.40%). The pattern showed that undergraduates of FOU and SOU had higher consumption of the following substances: Energy drink (63.30%, 60.80%), alcohol (50.70%, 53.70%), cigarette (47.01%, 50.01%), and marijuana (40.50%, 43.30), respectively. The undergraduates in FOU had highest knowledge mean score on the consequences of substance use (10.20 ± 4.21), followed by undergraduates of PO university (9.30 ± 4.80) and SOU (6.90 ± 4.80). Furthermore, there was a significant difference in prevalence of substance use across the universities (F = 2.19, p < 0.03). Also, there was a significant difference in knowledge mean score on the consequences of substance use and substance use across the universities (F = 3.29, p < 0.03). A significant association was found between the level of knowledge of consequences of substance use and substance use in SOU (β = 0.14, t(294) = 10.58, p ˂ 0.03), FOU (β = 0.33, t(298) 6.66 p ˂ 0.03) and PO university (β = 0.01, t(243) = 3.46 p ˂ 0.03) among undergraduates in selected universities in Lagos State.

Brackish groundwater (BGW) desalination is promising for producing freshwater, but the disposal of reverse osmosis concentrates (ROCs) poses environmental concerns. One strategy to minimize the volume of ROC is to remove scaling ions─a primary factor limiting water recovery due to membrane scaling─for the additional desalination of the treated ROC in a secondary reverse osmosis (RO) unit. While promising, electrochemical precipitation remains poorly understood in the presence of antiscalants, which are commonly added to the RO feed to inhibit precipitation. This study investigates the effects of antiscalants and their concentrations on a pH-mediated electrochemical process to remove scaling ions in the BGW ROC, using nitrilotris(methylenephosphonic) acid (NTMP) as a model antiscalant. The use of the hydrogen evolution reaction increased the catholyte pH, promoting the precipitation of Ca2+ and Mg2+ and reaching up to a hardness reduction of 93%. The inhibitory effect of NTMP on the formation of CaCO3 is more pronounced at low current densities, altered precipitate morphologies, and increased the energy consumption of precipitation. The inhibitory effect was observed both at the cathode surface and in the bulk solution and was also compared with that in chemical precipitation. These new findings highlight the capability of electrochemical precipitation as a viable method for brine management toward zero liquid discharge.

Up-to techniques' represent enhancements of the coinduction proof method and are widely used on coinductive behavioural relations such as bisimilarity. Abstract formulations of these coinductive techniques exist, using fixed-points or category theory. A proposal has been recently put forward for transporting the enhancements onto the concrete realms of inductive behavioural relations, i.e., relations defined from inductive observables, such as traces or enriched forms of traces. The abstract meaning of such 'inductive enhancements', however, has not been explored. In this paper, we review the theory, and then propose an abstract account of it, using fixed-point theory in complete lattices.

For decades, the airspace volume above today’s commercial traffic at altitudes higher than 60,000 ft - referred to as Higher Airspace (HA) in Europe, Upper Class E in the U.S. or sometimes Near Space - had been largely reserved for specialized military operations, experimental flights, rare exploration missions, and only occasionally interrupted by rocket launches. However, advancements in aerospace technology, a growing demand for expanded air travel, novel airborne capabilities, and a surge of (commercial) rockets launched to sub-orbital and orbital destinations, let to identifying the need to develop concepts for a more closely interfacing and later-on integration between Air Traffic Management (ATM) and Space Traffic Management (STM). Reasons for this are manifold, but they all can be summed up to the fact that methods developed have been done so in different contexts and different times: Procedures to allow crossing of airspace to reach higher altitudes have long lead times that leave little flexibility to adjust launch times to weather conditions or other unforeseen events. Covering against risk from unscheduled failures often requires closing large regions of air space, which does not scale with the number of launches expected over the coming decades. Additionally, every-now-and-then occurring reentries of large objects together with the inherent uncertainties of their predictions lead to closures of airspace that are questionable when considering the probability of casualty causing events, yet understandable when looking at the risk of being responsible if something occurs, without clear procedures and risk description. As an example, the brief closure of Spanish airspace in November 2022 in reaction to a reentering Chinese launcher stage, lead to the delay of more than 300 commercial flights.

(Abstracted from JAMA 2023;330:1991–1999 Worldwide, about 10% of pregnancies are affected by an abnormal rise in maternal blood pressure (BP). Individuals whose BP remains high 6 weeks after birth are more likely to have higher BP 5 to 10 years later.

ABSTRACT Experimental foundation has been established for improving corrosion models for stainless steels exposed to aqueous chloride media with low levels of dissolved oxygen. Accurate repassivation potentials were measured for UNS S31603 and UNS S32305 alloys in chloride electrolytes at room and elevated temperatures using Tsujikawa-Hisamatsu Electrochemical (THE) and Cyclic Potentiodynamic Polarization (CPP) methods. It was observed that the repassivation potential values measured from CPP methods were lower than the ones obtained from THE method for the same environmental conditions. Cyclic polarization scans in aqueous chloride media were conducted at different reverse scan rates resulting in varied repassivation potentials. Medium-term corrosion potentials were measured in chloride media with controlled oxygen levels ranging from 20 – 400 ppb. These results were used as inputs for improving model prediction for repassivation and corrosion potentials. With a flexible definition of the repassivation current density, the previously developed mechanistic repassivation model reproduces the experimental repassivation potentials obtained using THE and CPP methods. Dependence of corrosion potential on dissolved oxygen has been modeled using a mixed-potential model. It has been demonstrated that the effect of agitation (caused by bubbling of oxygen) needs to be accounted for to describe the corrosion potential, especially at low dissolved oxygen where mass transport is important.

Latin Amerika’daki bölgeselleşme girişimlerinden biri olan ve 1991 yılında Brezilya, Arjantin, Uruguay,Paraguay’ın imzaladığı anlaşma ile kurulan, 2012 yılında ise Venezuela’nın dahil olduğu GüneyAmerika Ortak Pazarı MERCOSUR, günümüzde bölgenin en büyük ticari bloğu olarak karşımızaçıkmaktadır. Nihai hedefinin ekonomik entegrasyon olduğu organizasyonun ilk yıllarında belirginbir başarı sağladığı görülse de kurumsallaşmasındaki eksiklikler, ülkelerin egemenliği devretmeyeisteksizlikleri, üyelerin bireysel politikaları ve Latin Amerika’da bulunan çok sayıda bölgesel örgütünvarlığından kaynaklı kapsayıcılığının sınırlı oluşu nedenleriyle bölgeselleşmesi istenilen düzeyeulaşamamıştır. Ekonomik bölgeselleşmenin bir göstergesi olarak bölge içi ticari ilişkilerin incelenmesiMERCOSUR’un son dönemdeki iktisadi entegrasyon düzeyi hakkında fikir vermektedir.Dünya sisteminde ekonomik bölgeselleşmenin temelleri 19.yy’da Avrupa’daki gelişmeleredayandırılmakta, yeni gelişen ticaret ağları ve ülkelerin gümrük birliği çalışmaları modern anlamdailk ekonomik bölgeselleşme girişimlerine örnek olarak değerlendirilebilmektedir. Bu dönemdeLatin Amerika’da daha çok Pan fikirlerin ve korumacılığın etkisiyle fikirsel, kültürel ve güvenliktemelli bölgeselleşme düşünceleri görülürken, ortak pazar kurma ve ticari ilişkilerde artış sağlamahedefleri 20.yy’ın ilk yarısında ortaya çıkmaktadır. Latin Amerika Ekonomik Komisyonu (ECLA)ile 1948 yılında başlayan ekonomik bölgeselleşme çalışmaları, 1990’lar sonrası kurumsallaşarakMERCOSUR halini almış, bölge içi ticaretin ve tüm üretim faktörleri düzeyinde ekonomik serbestliğinarttırılması hedeflenmiştir. 2006-2016 yılları arası veriler incelendiğinde GSYİH bakımından grubungöstergelerinde etkili olan Brezilya ve Arjantin’in kendi ticaret hacimlerini arttırdıkları ancak bunubölge içi değil bölge dışı ticaret partnerleri ile sağladıkları görülmüştür. Dolayısıyla kapasite farklılıklarıve ithalat bağımlılıkları gibi diğer sınırlılıklarıyla beraber Brezilya ve Arjantin’in ticaret tercihlerinin debölgeselleşmenin istenilen seviyeye ulaşamamasının bir nedeni olduğu ileri sürülebilmektedir.Latin Amerika bölgeselleşmesini ekonomik açıdan ele almayı hedefleyen çalışma, Avrupa dışındakibölgeselleşmenin bir örneği olarak MERCOSUR’un ekonomik bölgeselleşmesini değerlendirmektedir.Araştırmanın birinci bölümünde ekonomik bölgeselleşme çalışmaları, uluslararası ilişkilerdekifederalizm, fonksiyonalizm, neofonksiyonalizm ve hükümetler arasıcılık gibi bölgeselleşme teorileri kapsamında incelenecek, bölgeselleşmenin sosyal, güvenlik, normatif ve ekonomik biçimlerininolabileceği ortaya koyulacaktır. Bölümde ekonomik bölgeselleşmenin tercihli ticaret anlaşması, serbestticaret anlaşması, gümrük birliği, ortak pazar ve ekonomik birlik aşamalarına değinilecek, bölgeselleşmeve küreselleşme dalgalarının dünya ticaretine etkisi değerlendirilecektir. İkinci bölümde GüneyAmerika’da bölgeselleşme çalışmaları 19.yy’dan itibaren ele alınacak, MERCOSUR’un tarihsel gelişimiortaya koyulacaktır. Araştırmanın son bölümünde ise MERCOSUR’un ekonomik bölgeselleşmesi,bölge içi ve dışı ticaret hacimleri ve ülkelerin ticari partnerleri açısından değerlendirilecek, LatinAmerika bölgeselleşmesinin fırsatları ve sınırlılıkları analiz edilecektir.