1,474 research outputs found
Earth, humans, and metals: investigating the role of iron and other metals in the atmospheric, oceanic, and energy systems
Includes bibliographical references.2022 Fall.Metals such as iron and copper have been an integral component of the Earth system since its beginnings and have formed the basis for modern human civilization growth since the Bronze and Iron Ages. Human activities include metals at various levels, from burning coal in power plants and mining ores lead to emissions of particulate and gaseous metallic products into the atmosphere. While suspended in the air, metal oxides such as hematite and magnetite absorb solar radiation, thus warming the atmosphere. After falling into the oceans, metals such as iron and magnesium act as important nutrients for oceanic biota, and thus affect the marine nutrient and carbon cycles. Human activities have increased many-fold since the beginning of the Industrial Era, and as the world moves from fossil fuel to renewable energy to reduce carbon emissions, the demand for metals is also projected to increase many folds. Yet, the past, present, and future impacts of anthropogenic activities on the atmospheric and marine metal cycles, particularly iron, remain poorly understood.In Chapter 2, I estimate the atmospheric radiative and oceanic biological impacts of anthropogenic iron emissions over the Industrial Era. I perform simulations using a mineralogy-based inventory and an Earth System Model and estimate the 1850-to-2010 global mean direct radiative forcing by anthropogenic iron to be +0.02 to +0.10 W/m2. I estimate that the enhanced phytoplankton primary production due to anthropogenic soluble iron deposition over the last 150 years caused carbon dioxide (CO2) sequestration of 0.2-13 ppmv. This sequestered CO2 also led to an 'avoided' CO2 forcing of -0.002 to -0.16 W/m2. While globally small, these impacts can be higher in specific regions; the anthropogenic iron oxide direct radiative forcing is +0.5 W/m2 over areas such as East Asia and India with more coal combustion and metal smelting. Anthropogenic soluble iron sustains >10% of marine net primary productivity in the high-latitude North Pacific Ocean, a region vulnerable to thermal stratification due to climate change. In Chapter 3, I focus on evaluating anthropogenic total iron emissions using observations and models. Performing the model-observation comparison only at sites where the modeled anthropogenic contribution is the highest, I find that the current emission inventory underestimates anthropogenic total iron emissions from North America and Europe by a factor of 3-5. Further isolating anthropogenic sectoral emissions over North America using Positive Matrix Factorization, I find that smelting and coal combustion emissions are overestimated by a factor of 3-10 in the current emission inventory, whereas heavy fuel oil emissions from ships and industrial boilers are underestimated by a factor of 2-5. By comparing modeled concentrations of iron oxides with observations from Japan, I find that the current smelting and coal combustion emissions from East Asia are only slightly overestimated in the inventory, by a factor of 1.2-1.5. Finally, in Chapter 4, I explore the regionality and magnitude of PM2.5 emissions from metal mining and smelting to meet projected global renewable energy demand. I estimate future PM2.5 (particulate matter smaller than 2.5 μm diameter) emissions from mining and smelting to meet the metal demand of renewable energy technologies in two climate pathways to be 0.3-0.6 Tg/yr in the 2020-2050 period, which is projected to contribute 10-30% of total anthropogenic primary PM2.5 combustion emissions in many countries. The concentration of mineral reserves in a few regions means the impacts are also regionally concentrated. Rapid decarbonization could lead to a faster reduction of overall anthropogenic PM2.5 emissions but also could create more unevenness in the distributions of emissions relative to where demand occurs
Atomic fountain of laser-cooled Yb atoms for precision measurements
We demonstrate launching of laser-cooled Yb atoms in a cold atomic fountain.
Atoms in a collimated thermal beam are first cooled and captured in a
magneto-optic trap (MOT) operating on the strongly-allowed transition at 399~nm (blue line). They are then transferred to a MOT
on the weakly-allowed transition at 556~nm (green
line). Cold atoms from the green MOT are launched against gravity at a velocity
of around 2.5~m/s using a pair of green beams. We trap more than atoms
in the blue MOT and transfer up to 70\% into the green MOT. The temperature for
the odd isotope, Yb, is 1~mK in the blue MOT, and reduces by a
factor of 40 in the green MOT.Comment: 6 pages, 7 figure
Highly-cited estimates of the cumulative incidence and recurrence of vulvovaginal candidiasis are inadequately documented.
BACKGROUND: Available literature concerning the epidemiologic or clinical features of vulvovaginal candidiasis commonly reports that: 75% of women will experience an episode of vulvovaginal candidiasis in their lifetimes, 50% of whom will experience at least a second episode, and 5-10% of all women will experience recurrent vulvovaginal candidiasis (≥4 episodes/1 year). In this debate we traced the three commonly cited statistics to their presumed origins. DISCUSSION: It is apparent that these figures were inadequately documented and lacked supporting epidemiologic evidence. Population-based studies are needed to make reliable estimates of the lifetime risk of vulvovaginal candidiasis and the proportion of women who experience recurrent candidiasis. SUMMARY: The extent to which vulvovaginal candidiasis is a source of population-level morbidity remains uncertain
Vamana Karma in Tamaka Shwasa - A Case Study
Tamaka Shwasa is a very common disease in India. The prevalence of the disease is increasing day by day due to genetic susceptibility, Pollution, environmental factor, stressful life, abnormal Food style that all exposes the humans to suffer from Tamaka Shwasa. Ayurveda the science of life describes the management of lifestyle diseases. In the form of proper dietary, its behavioral management i.e., daily regimen and seasonal regimen, seasonal detoxification and rejuvenation therapies In Ayurveda Shodhana (Purification) Shamana (Pacification) and Nidana Parivarjana (avoiding causative factors) are the three folds of fundamental therapeutic management of the disease. Panchakarma is Ayurveda’s prime Shodhana procedures which is basically group of detoxification procedures. In Ayurveda text Tamaka Shwasa is a disease which Is Kapha Vata Dosha predominant and disease of Pranavaha Strotasa. Tamaka Shwasa is clinically much resembled with bronchial asthma. Here Panchakarma procedure is quite effective which is based on situation of patient. In present case study Panchakarma procedure i.e., Vasantik Vamana was given to the patient for management of Tamaka Shwasa
Virechana Karma in Eczema (Kshudra Kushtha) : A Case Study
Panchakarma therapy aims at the elimination of excessive Doshas from the body to maintain the state of health for a longer duration, while the Shamana therapy is for suppression of vitiated Doshas within the body. Virechana is one of the Panchakarma therapy. Virechana is the bio-purification procedure of Ayurveda when Doshas are expelled out from the body through the anal route then it is called Virechana. Normally, after Virechana Karma, patient does not complain of having any untoward like those present after diarrhea due to dehydration. Thus, Virechana Karma is one of the important bio-purificative method which is indicated for complete elimination of Doshas and thus result in eradication of diseases. Patient was treated with Shodhana in the form of Virechana Karma followed by oral medication. The patient reported symptomatic improvement
Delays in reporting of cancer cervix in rural India: sociodemographic and reproductive correlation
Background: Cervical cancer, caused by sexually-acquired infection with human papillomavirus (HPV), continues to be a public health problem worldwide as it claims the lives of more than 270,000 women every year. The majority of cervical cancer deaths (85%) occur in women living in low- and middle-income countries. Assessment of socio-demographic profile and reproductive history gives a better picture of the determinants of cervical carcinoma in low-resource settings.Methods: This hospital-based cross-sectional study was undertaken at a Regional Cancer Institute at Aurangabad, India. Hundred newly diagnosed women with advanced cervical cancer (stage 2B-4B), who were undertaking radiotherapy and/or chemotherapy, were included to assess their socio-demographic, reproductive and clinical profile. The causes for late presentations were also noted.Results: The mean age of women at the time of detection of cervical cancer was 57.35 years (30-82 years). More than 81% of patients were illiterate and belonged to low socioeconomic status. 47% of the study subjects had their first sexual experience before 15 years of age. Nearly 78% women had 5 or more pregnancies, among them, unusual discharge from vagina (39%) followed by bleeding after menopause (28%) and pain in abdomen (13%) were the most common presenting complaints. The average duration of symptoms was (28 days), time interval between the symptoms and biopsy was (3.6 months). Combination of radiotherapy and chemotherapy was the most common modality of treatment. Most common cause of delay in diagnosis was lack of awareness about the symptom of cancer (11%), feeling ashamed (10%), no one paid attention (19%), not diagnosed and referred at periphery and financial causes (23%) were found.Conclusions: Prevention of cervical cancer include delaying the age at initiation of sexual activity to above 18 years, spreading cancer awareness in women and with well-equipped health workers with diagnosis and knowledge of cancer cervix. This can prevent the medical and patient delay in the diagnosis of cancer cervix
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